Merge upstream/development

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

41 files changed, 3729 insertions, 2787 deletions

diff --git a/src/backends/sqlite.c b/src/backends/sqlite.c
index b4c941a59..a4c6d4825 100644
--- a/src/backends/sqlite.c
+++ b/src/backends/sqlite.c
@@ -44,21 +44,20 @@ typedef struct {
 	sqlite3_stmt *st_read_header;
 } sqlite_backend;
 
-int sqlite_backend__read_header(git_rawobj *obj, git_odb_backend *_backend, const git_oid *oid)
+int sqlite_backend__read_header(size_t *len_p, git_otype *type_p, git_odb_backend *_backend, const git_oid *oid)
 {
 	sqlite_backend *backend;
 	int error;
 
-	assert(obj && _backend && oid);
+	assert(len_p && type_p && _backend && oid);
 
 	backend = (sqlite_backend *)_backend;
 	error = GIT_ERROR;
-	obj->data = NULL;
 
 	if (sqlite3_bind_text(backend->st_read_header, 1, (char *)oid->id, 20, SQLITE_TRANSIENT) == SQLITE_OK) {
 		if (sqlite3_step(backend->st_read_header) == SQLITE_ROW) {
-			obj->type = sqlite3_column_int(backend->st_read_header, 0);
-			obj->len = sqlite3_column_int(backend->st_read_header, 1);
+			*type_p = (git_otype)sqlite3_column_int(backend->st_read_header, 0);
+			*len_p = (size_t)sqlite3_column_int(backend->st_read_header, 1);
 			assert(sqlite3_step(backend->st_read_header) == SQLITE_DONE);
 			error = GIT_SUCCESS;
 		} else {
@@ -71,26 +70,26 @@ int sqlite_backend__read_header(git_rawobj *obj, git_odb_backend *_backend, cons
 }
 
 
-int sqlite_backend__read(git_rawobj *obj, git_odb_backend *_backend, const git_oid *oid)
+int sqlite_backend__read(void **data_p, size_t *len_p, git_otype *type_p, git_odb_backend *_backend, const git_oid *oid)
 {
 	sqlite_backend *backend;
 	int error;
 
-	assert(obj && _backend && oid);
+	assert(data_p && len_p && type_p && _backend && oid);
 
 	backend = (sqlite_backend *)_backend;
 	error = GIT_ERROR;
 
 	if (sqlite3_bind_text(backend->st_read, 1, (char *)oid->id, 20, SQLITE_TRANSIENT) == SQLITE_OK) {
 		if (sqlite3_step(backend->st_read) == SQLITE_ROW) {
-			obj->type = sqlite3_column_int(backend->st_read, 0);
-			obj->len = sqlite3_column_int(backend->st_read, 1);
-			obj->data = git__malloc(obj->len);
+			*type_p = (git_otype)sqlite3_column_int(backend->st_read, 0);
+			*len_p = (size_t)sqlite3_column_int(backend->st_read, 1);
+			*data_p = git__malloc(*len_p);
 
-			if (obj->data == NULL) {
+			if (*data_p == NULL) {
 				error = GIT_ENOMEM;
 			} else {
-				memcpy(obj->data, sqlite3_column_blob(backend->st_read, 2), obj->len);
+				memcpy(*data_p, sqlite3_column_blob(backend->st_read, 2), *len_p);
 				error = GIT_SUCCESS;
 			}
 
@@ -126,27 +125,24 @@ int sqlite_backend__exists(git_odb_backend *_backend, const git_oid *oid)
 }
 
 
-int sqlite_backend__write(git_oid *id, git_odb_backend *_backend, git_rawobj *obj)
+int sqlite_backend__write(git_oid *id, git_odb_backend *_backend, const void *data, size_t len, git_otype type)
 {
-	char hdr[64];
-	int  hdrlen;
-
 	int error;
 	sqlite_backend *backend;
 
-	assert(id && _backend && obj);
+	assert(id && _backend && data);
 
 	backend = (sqlite_backend *)_backend;
 
-	if ((error = git_odb__hash_obj(id, hdr, sizeof(hdr), &hdrlen, obj)) < 0)
+	if ((error = git_odb_hash(id, data, len, type)) < 0)
 		return error;
 
 	error = SQLITE_ERROR;
 
 	if (sqlite3_bind_text(backend->st_write, 1, (char *)id->id, 20, SQLITE_TRANSIENT) == SQLITE_OK &&
-		sqlite3_bind_int(backend->st_write, 2, (int)obj->type) == SQLITE_OK &&
-		sqlite3_bind_int(backend->st_write, 3, obj->len) == SQLITE_OK &&
-		sqlite3_bind_blob(backend->st_write, 4, obj->data, obj->len, SQLITE_TRANSIENT) == SQLITE_OK) {
+		sqlite3_bind_int(backend->st_write, 2, (int)type) == SQLITE_OK &&
+		sqlite3_bind_int(backend->st_write, 3, len) == SQLITE_OK &&
+		sqlite3_bind_blob(backend->st_write, 4, data, len, SQLITE_TRANSIENT) == SQLITE_OK) {
 		error = sqlite3_step(backend->st_write);
 	}
 
@@ -272,4 +268,13 @@ cleanup:
 	return GIT_ERROR;
 }
 
+#else
+
+int git_odb_backend_sqlite(git_odb_backend **GIT_UNUSED(backend_out), const char *GIT_UNUSED(sqlite_db))
+{
+	GIT_UNUSED_ARG(backend_out);
+	GIT_UNUSED_ARG(sqlite_db);
+	return GIT_ENOTIMPLEMENTED;
+}
+
 #endif /* HAVE_SQLITE3 */
diff --git a/src/blob.c b/src/blob.c
index f157f4787..bc0a08a8a 100644
--- a/src/blob.c
+++ b/src/blob.c
@@ -33,106 +33,89 @@
 const void *git_blob_rawcontent(git_blob *blob)
 {
 	assert(blob);
-	
-	if (blob->content.data != NULL)
-		return blob->content.data;
-
-	if (blob->object.in_memory)
-		return NULL;
-
-	if (!blob->object.source.open && git_object__source_open((git_object *)blob) < GIT_SUCCESS)
-		return NULL;
-
-	return blob->object.source.raw.data;
+	return blob->odb_object->raw.data;
 }
 
 int git_blob_rawsize(git_blob *blob)
 {
 	assert(blob);
-
-	if (blob->content.data != NULL)
-		return blob->content.len;
-
-	return blob->object.source.raw.len;
+	return blob->odb_object->raw.len;
 }
 
 void git_blob__free(git_blob *blob)
 {
-	gitfo_free_buf(&blob->content);
+	git_odb_object_close(blob->odb_object);
 	free(blob);
 }
 
-int git_blob__parse(git_blob *blob)
+int git_blob__parse(git_blob *blob, git_odb_object *odb_obj)
 {
 	assert(blob);
+	git_cached_obj_incref((git_cached_obj *)odb_obj);
+	blob->odb_object = odb_obj;
 	return GIT_SUCCESS;
 }
 
-int git_blob__writeback(git_blob *blob, git_odb_source *src)
-{
-	assert(blob->object.modified);
-
-	if (blob->content.data == NULL)
-		return GIT_EMISSINGOBJDATA;
-
-	return git__source_write(src, blob->content.data, blob->content.len);
-}
-
-int git_blob_set_rawcontent(git_blob *blob, const void *buffer, size_t len)
+int git_blob_create_frombuffer(git_oid *oid, git_repository *repo, const void *buffer, size_t len)
 {
-	assert(blob && buffer);
-
-	blob->object.modified = 1;
-
-	git_object__source_close((git_object *)blob);
-
-	if (blob->content.data != NULL)
-		gitfo_free_buf(&blob->content);
+	int error;
+	git_odb_stream *stream;
 
-	blob->content.data = git__malloc(len);
-	blob->content.len = len;
+	if ((error = git_odb_open_wstream(&stream, repo->db, len, GIT_OBJ_BLOB)) < GIT_SUCCESS)
+		return error;
 
-	if (blob->content.data == NULL)
-		return GIT_ENOMEM;
+	stream->write(stream, buffer, len);
 
-	memcpy(blob->content.data, buffer, len);
+	error = stream->finalize_write(oid, stream);
+	stream->free(stream);
 
-	return GIT_SUCCESS;
+	return error;
 }
 
-int git_blob_set_rawcontent_fromfile(git_blob *blob, const char *filename)
+int git_blob_create_fromfile(git_oid *oid, git_repository *repo, const char *path)
 {
-	assert(blob && filename);
-	blob->object.modified = 1;
+	int error, fd;
+	char full_path[GIT_PATH_MAX];
+	char buffer[2048];
+	git_off_t size;
+	git_odb_stream *stream;
 
-	if (blob->content.data != NULL)
-		gitfo_free_buf(&blob->content);
-
-	return gitfo_read_file(&blob->content, filename);
-}
+	if (repo->path_workdir == NULL)
+		return GIT_ENOTFOUND;
 
-int git_blob_writefile(git_oid *written_id, git_repository *repo, const char *path)
-{
-	int error;
-	git_blob *blob;
+	git__joinpath(full_path, repo->path_workdir, path);
 
-	if (gitfo_exists(path) < 0)
+	if ((fd = gitfo_open(full_path, O_RDONLY)) < 0)
 		return GIT_ENOTFOUND;
 
-	if ((error = git_blob_new(&blob, repo)) < GIT_SUCCESS)
-		return error;
+	if ((size = gitfo_size(fd)) < 0 || !git__is_sizet(size)) {
+		gitfo_close(fd);
+		return GIT_EOSERR;
+	}
 
-	if ((error = git_blob_set_rawcontent_fromfile(blob, path)) < GIT_SUCCESS)
+	if ((error = git_odb_open_wstream(&stream, repo->db, (size_t)size, GIT_OBJ_BLOB)) < GIT_SUCCESS) {
+		gitfo_close(fd);
 		return error;
+	}
 
-	if ((error = git_object_write((git_object *)blob)) < GIT_SUCCESS)
-		return error;
+	while (size > 0) {
+		ssize_t read_len;
 
-	git_oid_cpy(written_id, git_object_id((git_object *)blob));
+		read_len = read(fd, buffer, sizeof(buffer));
 
-	/* FIXME: maybe we don't want to free this already?
-	 * the user may want to access it again */
-	GIT_OBJECT_DECREF(repo, blob);
-	return GIT_SUCCESS;
+		if (read_len < 0) {
+			gitfo_close(fd);
+			stream->free(stream);
+			return GIT_EOSERR;
+		}
+
+		stream->write(stream, buffer, read_len);
+		size -= read_len;
+	}
+
+	error = stream->finalize_write(oid, stream);
+	stream->free(stream);
+
+	return error;
 }
 
diff --git a/src/blob.h b/src/blob.h
index febc296fe..4300d7e54 100644
--- a/src/blob.h
+++ b/src/blob.h
@@ -3,15 +3,15 @@
 
 #include "git2/blob.h"
 #include "repository.h"
+#include "odb.h"
 #include "fileops.h"
 
 struct git_blob {
 	git_object object;
-	gitfo_buf content;
+	git_odb_object *odb_object;
 };
 
 void git_blob__free(git_blob *blob);
-int git_blob__parse(git_blob *blob);
-int git_blob__writeback(git_blob *blob, git_odb_source *src);
+int git_blob__parse(git_blob *blob, git_odb_object *obj);
 
 #endif
diff --git a/src/cache.c b/src/cache.c
new file mode 100644
index 000000000..fd42e2c5b
--- /dev/null
+++ b/src/cache.c
@@ -0,0 +1,161 @@
+/*
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * In addition to the permissions in the GNU General Public License,
+ * the authors give you unlimited permission to link the compiled
+ * version of this file into combinations with other programs,
+ * and to distribute those combinations without any restriction
+ * coming from the use of this file.  (The General Public License
+ * restrictions do apply in other respects; for example, they cover
+ * modification of the file, and distribution when not linked into
+ * a combined executable.)
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "common.h"
+#include "repository.h"
+#include "commit.h"
+#include "thread-utils.h"
+#include "cache.h"
+
+#define GIT_CACHE_OPENADR 3
+
+
+void git_cache_init(git_cache *cache, size_t size, git_cached_obj_freeptr free_ptr)
+{
+	size_t i;
+
+	if (size < 8)
+		size = 8;
+
+	/* round up size to closest power of 2 */
+	size--;
+	size |= size >> 1;
+	size |= size >> 2;
+	size |= size >> 4;
+	size |= size >> 8;
+	size |= size >> 16;
+
+	cache->size_mask = size;
+	cache->lru_count = 0;
+	cache->free_obj = free_ptr;
+
+	cache->nodes = git__malloc((size + 1) * sizeof(cache_node));
+
+	for (i = 0; i < (size + 1); ++i) {
+		git_mutex_init(&cache->nodes[i].lock);
+		cache->nodes[i].ptr = NULL;
+		cache->nodes[i].lru = 0;
+	}
+}
+
+void git_cache_free(git_cache *cache)
+{
+	size_t i;
+
+	for (i = 0; i < (cache->size_mask + 1); ++i) {
+		if (cache->nodes[i].ptr)
+			git_cached_obj_decref(cache->nodes[i].ptr, cache->free_obj);
+
+		git_mutex_free(&cache->nodes[i].lock);
+	}
+
+	free(cache->nodes);
+}
+
+void *git_cache_get(git_cache *cache, const git_oid *oid)
+{
+	const uint32_t *hash;
+	size_t i, pos, found = 0;
+	cache_node *node = NULL;
+
+	hash = (const uint32_t *)oid->id;
+
+	for (i = 0; !found && i < GIT_CACHE_OPENADR; ++i) {
+		pos = hash[i] & cache->size_mask;
+		node = &cache->nodes[pos];
+
+		git_mutex_lock(&node->lock);
+		{
+			if (node->ptr && git_cached_obj_compare(node->ptr, oid) == 0) {
+				git_cached_obj_incref(node->ptr);
+				node->lru = ++cache->lru_count;
+				found = 1;
+			}
+		}
+		git_mutex_unlock(&node->lock);
+	}
+
+
+	return found ? node->ptr : NULL;
+}
+
+void *git_cache_try_store(git_cache *cache, void *entry)
+{
+	cache_node *nodes[GIT_CACHE_OPENADR], *lru_node;
+	const uint32_t *hash;
+	const git_oid *oid;
+	size_t i;
+
+	oid = &((git_cached_obj*)entry)->oid;
+	hash = (const uint32_t *)oid->id;
+
+	/* increase the refcount on this object, because
+	 * the cache now owns it */
+	git_cached_obj_incref(entry);
+
+	for (i = 0; i < GIT_CACHE_OPENADR; ++i) {
+		size_t pos = hash[i] & cache->size_mask;
+
+		nodes[i] = &cache->nodes[pos];
+		git_mutex_lock(&nodes[i]->lock);
+	}
+
+	lru_node = nodes[0];
+
+	for (i = 0; i < GIT_CACHE_OPENADR; ++i) {
+
+		if (nodes[i]->ptr == NULL) {
+			nodes[i]->ptr = entry;
+			nodes[i]->lru = ++cache->lru_count;
+			break;
+		} else if (git_cached_obj_compare(nodes[i]->ptr, oid) == 0) {
+			git_cached_obj_decref(entry, cache->free_obj);
+			entry = nodes[i]->ptr;
+			nodes[i]->lru = ++cache->lru_count;
+			break;
+		}
+
+		if (nodes[i]->lru < lru_node->lru)
+			lru_node = nodes[i];
+	}
+
+	if (i == GIT_CACHE_OPENADR) {
+		void *old_entry = lru_node->ptr;
+		assert(old_entry);
+
+		git_cached_obj_decref(old_entry, cache->free_obj);
+		lru_node->ptr = entry;
+		lru_node->lru = ++cache->lru_count;
+	}
+
+	/* increase the refcount again, because we are
+	 * returning it to the user */
+	git_cached_obj_incref(entry);
+
+	for (i = 0; i < GIT_CACHE_OPENADR; ++i)
+		git_mutex_unlock(&nodes[i]->lock);
+
+	return entry;
+}
diff --git a/src/cache.h b/src/cache.h
new file mode 100644
index 000000000..975aaff7e
--- /dev/null
+++ b/src/cache.h
@@ -0,0 +1,59 @@
+#ifndef INCLUDE_cache_h__
+#define INCLUDE_cache_h__
+
+#include "git2/common.h"
+#include "git2/oid.h"
+#include "git2/odb.h"
+
+#include "thread-utils.h"
+
+#define GIT_DEFAULT_CACHE_SIZE 128
+
+typedef void (*git_cached_obj_freeptr)(void *);
+
+typedef struct {
+	git_oid oid;
+	git_atomic refcount;
+} git_cached_obj;
+
+typedef struct {
+	git_cached_obj *ptr;
+	git_mutex lock;
+	unsigned int lru;
+} cache_node;
+
+typedef struct {
+	cache_node *nodes;
+
+	unsigned int lru_count;
+	size_t size_mask;
+	git_cached_obj_freeptr free_obj;
+} git_cache;
+
+
+void git_cache_init(git_cache *cache, size_t size, git_cached_obj_freeptr free_ptr);
+void git_cache_free(git_cache *cache);
+
+void *git_cache_try_store(git_cache *cache, void *entry);
+void *git_cache_get(git_cache *cache, const git_oid *oid);
+
+
+GIT_INLINE(int) git_cached_obj_compare(git_cached_obj *obj, const git_oid *oid)
+{
+	return git_oid_cmp(&obj->oid, oid);
+}
+
+GIT_INLINE(void) git_cached_obj_incref(git_cached_obj *obj)
+{
+	git_atomic_inc(&obj->refcount);
+}
+
+GIT_INLINE(void) git_cached_obj_decref(git_cached_obj *obj, git_cached_obj_freeptr free_obj)
+{
+	if (git_atomic_dec(&obj->refcount) == 0)
+		free_obj(obj);
+}
+
+
+
+#endif
diff --git a/src/commit.c b/src/commit.c
index 974999a4a..03b111da5 100644
--- a/src/commit.c
+++ b/src/commit.c
@@ -29,10 +29,12 @@
 #include "git2/signature.h"
 
 #include "common.h"
+#include "odb.h"
 #include "commit.h"
-#include "revwalk.h"
 #include "signature.h"
 
+#include <stdarg.h>
+
 #define COMMIT_BASIC_PARSE 0x0
 #define COMMIT_FULL_PARSE 0x1
 
@@ -46,24 +48,22 @@ static void clear_parents(git_commit *commit)
 {
 	unsigned int i;
 
-	for (i = 0; i < commit->parents.length; ++i) {
-		git_commit *parent = git_vector_get(&commit->parents, i);
-		GIT_OBJECT_DECREF(commit->object.repo, parent);
+	for (i = 0; i < commit->parent_oids.length; ++i) {
+		git_oid *parent = git_vector_get(&commit->parent_oids, i);
+		free(parent);
 	}
 
-	git_vector_clear(&commit->parents);
+	git_vector_clear(&commit->parent_oids);
 }
 
 void git_commit__free(git_commit *commit)
 {
 	clear_parents(commit);
-	git_vector_free(&commit->parents);
+	git_vector_free(&commit->parent_oids);
 
 	git_signature_free(commit->author);
 	git_signature_free(commit->committer);
 
-	GIT_OBJECT_DECREF(commit->object.repo, commit->tree);
-
 	free(commit->message);
 	free(commit->message_short);
 	free(commit);
@@ -74,100 +74,199 @@ const git_oid *git_commit_id(git_commit *c)
 	return git_object_id((git_object *)c);
 }
 
-int git_commit__writeback(git_commit *commit, git_odb_source *src)
+
+int git_commit_create_v(
+		git_oid *oid,
+		git_repository *repo,
+		const char *update_ref,
+		const git_signature *author,
+		const git_signature *committer,
+		const char *message,
+		const git_oid *tree_oid,
+		int parent_count,
+		...)
 {
-	unsigned int i;
+	va_list ap;
+	int i, error;
+	const git_oid **oids;
 
-	if (commit->tree == NULL)
-		return GIT_EMISSINGOBJDATA;
+	oids = git__malloc(parent_count * sizeof(git_oid *));
 
-	git__write_oid(src, "tree", git_tree_id(commit->tree));
+	va_start(ap, parent_count);
+	for (i = 0; i < parent_count; ++i)
+		oids[i] = va_arg(ap, const git_oid *);
+	va_end(ap);
 
-	for (i = 0; i < commit->parents.length; ++i) {
-		git_commit *parent;
+	error = git_commit_create(
+		oid, repo, update_ref, author, committer, message,
+		tree_oid, parent_count, oids);
 
-		parent = git_vector_get(&commit->parents, i);
-		git__write_oid(src, "parent", git_commit_id(parent));
-	}
+	free((void *)oids);
+	return error;
+}
 
-	if (commit->author == NULL)
-		return GIT_EMISSINGOBJDATA;
+int git_commit_create_ov(
+		git_oid *oid,
+		git_repository *repo,
+		const char *update_ref,
+		const git_signature *author,
+		const git_signature *committer,
+		const char *message,
+		const git_tree *tree,
+		int parent_count,
+		...)
+{
+	va_list ap;
+	int i, error;
+	const git_oid **oids;
 
-	git_signature__write(src, "author", commit->author);
+	oids = git__malloc(parent_count * sizeof(git_oid *));
 
-	if (commit->committer == NULL)
-		return GIT_EMISSINGOBJDATA;
+	va_start(ap, parent_count);
+	for (i = 0; i < parent_count; ++i)
+		oids[i] = git_object_id(va_arg(ap, const git_object *));
+	va_end(ap);
 
-	git_signature__write(src, "committer", commit->committer);
+	error = git_commit_create(
+		oid, repo, update_ref, author, committer, message,
+		git_object_id((git_object *)tree),
+		parent_count, oids);
 
-	if (commit->message != NULL) {
-		git__source_write(src, "\n", 1);
-		git__source_write(src, commit->message, strlen(commit->message));
-        }
+	free((void *)oids);
+	return error;
+}
 
-	/* Mark the commit as having all attributes */
-	commit->full_parse = 1;
+int git_commit_create_o(
+		git_oid *oid,
+		git_repository *repo,
+		const char *update_ref,
+		const git_signature *author,
+		const git_signature *committer,
+		const char *message,
+		const git_tree *tree,
+		int parent_count,
+		const git_commit *parents[])
+{
+	int i, error;
+	const git_oid **oids;
 
-	return GIT_SUCCESS;
+	oids = git__malloc(parent_count * sizeof(git_oid *));
+
+	for (i = 0; i < parent_count; ++i)
+		oids[i] = git_object_id((git_object *)parents[i]);
+
+	error = git_commit_create(
+		oid, repo, update_ref, author, committer, message,
+		git_object_id((git_object *)tree),
+		parent_count, oids);
+	
+	free((void *)oids);
+	return error;
 }
 
-int commit_parse_buffer(git_commit *commit, void *data, size_t len, unsigned int parse_flags)
+int git_commit_create(
+		git_oid *oid,
+		git_repository *repo,
+		const char *update_ref,
+		const git_signature *author,
+		const git_signature *committer,
+		const char *message,
+		const git_oid *tree_oid,
+		int parent_count,
+		const git_oid *parents[])
 {
-	char *buffer = (char *)data;
-	const char *buffer_end = (char *)data + len;
+	size_t final_size = 0;
+	int message_length, author_length, committer_length;
 
-	git_oid oid;
-	int error;
+	char *author_str, *committer_str;
 
-	/* first parse; the vector hasn't been initialized yet */
-	if (commit->parents.contents == NULL) {
-		git_vector_init(&commit->parents, 4, NULL);
-	}
+	int error, i;
+	git_odb_stream *stream;
 
-	clear_parents(commit);
+	message_length = strlen(message);
+	author_length = git_signature__write(&author_str, "author", author);
+	committer_length = git_signature__write(&committer_str, "committer", committer);
 
+	if (author_length < 0 || committer_length < 0)
+		return GIT_ENOMEM;
 
-	if ((error = git__parse_oid(&oid, &buffer, buffer_end, "tree ")) < GIT_SUCCESS)
-		return error;
+	final_size += GIT_OID_LINE_LENGTH("tree");
+	final_size += GIT_OID_LINE_LENGTH("parent") * parent_count;
+	final_size += author_length;
+	final_size += committer_length;
+	final_size += 1 + message_length;
 
-	GIT_OBJECT_DECREF(commit->object.repo, commit->tree);
-	if ((error = git_object_lookup((git_object **)&commit->tree, commit->object.repo, &oid, GIT_OBJ_TREE)) < GIT_SUCCESS)
+	if ((error = git_odb_open_wstream(&stream, repo->db, final_size, GIT_OBJ_COMMIT)) < GIT_SUCCESS)
 		return error;
 
-	/*
-	 * TODO: commit grafts!
-	 */
+	git__write_oid(stream, "tree", tree_oid);
+
+	for (i = 0; i < parent_count; ++i)
+		git__write_oid(stream, "parent", parents[i]);
+
+	stream->write(stream, author_str, author_length);
+	free(author_str);
+
+	stream->write(stream, committer_str, committer_length);
+	free(committer_str);
 
-	while (git__parse_oid(&oid, &buffer, buffer_end, "parent ") == GIT_SUCCESS) {
-		git_commit *parent;
 
-		if ((error = git_object_lookup((git_object **)&parent, commit->object.repo, &oid, GIT_OBJ_COMMIT)) < GIT_SUCCESS)
+	stream->write(stream, "\n", 1);
+	stream->write(stream, message, message_length);
+
+	error = stream->finalize_write(oid, stream);
+	stream->free(stream);
+
+	if (error == GIT_SUCCESS && update_ref != NULL) {
+		git_reference *head;
+
+		error = git_reference_lookup(&head, repo, update_ref);
+		if (error < GIT_SUCCESS)
 			return error;
 
-		if (git_vector_insert(&commit->parents, parent) < GIT_SUCCESS)
-			return GIT_ENOMEM;
+		if (git_reference_type(head) == GIT_REF_SYMBOLIC) {
+			if ((error = git_reference_resolve(&head, head)) < GIT_SUCCESS)
+				return error;
+		}
+
+		error = git_reference_set_oid(head, oid);
 	}
 
+	return error;
+}
 
-	if (parse_flags & COMMIT_FULL_PARSE) {
-		if (commit->author)
-			git_signature_free(commit->author);
+int commit_parse_buffer(git_commit *commit, void *data, size_t len)
+{
+	char *buffer = (char *)data;
+	const char *buffer_end = (char *)data + len;
 
-		commit->author = git__malloc(sizeof(git_signature));
-		if ((error = git_signature__parse(commit->author, &buffer, buffer_end, "author ")) < GIT_SUCCESS)
-			return error;
+	git_oid parent_oid;
+	int error;
 
-	} else {
-		if ((buffer = memchr(buffer, '\n', buffer_end - buffer)) == NULL)
-			return GIT_EOBJCORRUPTED;
+	git_vector_init(&commit->parent_oids, 4, NULL);
 
-		buffer++;
+	if ((error = git__parse_oid(&commit->tree_oid, &buffer, buffer_end, "tree ")) < GIT_SUCCESS)
+		return error;
+
+	/*
+	 * TODO: commit grafts!
+	 */
+
+	while (git__parse_oid(&parent_oid, &buffer, buffer_end, "parent ") == GIT_SUCCESS) {
+		git_oid *new_oid;
+
+		new_oid = git__malloc(sizeof(git_oid));
+		git_oid_cpy(new_oid, &parent_oid);
+
+		if (git_vector_insert(&commit->parent_oids, new_oid) < GIT_SUCCESS)
+			return GIT_ENOMEM;
 	}
 
-	/* Always parse the committer; we need the commit time */
-	if (commit->committer)
-		git_signature_free(commit->committer);
+	commit->author = git__malloc(sizeof(git_signature));
+	if ((error = git_signature__parse(commit->author, &buffer, buffer_end, "author ")) < GIT_SUCCESS)
+		return error;
 
+	/* Always parse the committer; we need the commit time */
 	commit->committer = git__malloc(sizeof(git_signature));
 	if ((error = git_signature__parse(commit->committer, &buffer, buffer_end, "committer ")) < GIT_SUCCESS)
 		return error;
@@ -176,7 +275,7 @@ int commit_parse_buffer(git_commit *commit, void *data, size_t len, unsigned int
 	while (buffer <= buffer_end && *buffer == '\n')
 		buffer++;
 
-	if (parse_flags & COMMIT_FULL_PARSE && buffer < buffer_end) {
+	if (buffer < buffer_end) {
 		const char *line_end;
 		size_t message_len = buffer_end - buffer;
 
@@ -199,160 +298,44 @@ int commit_parse_buffer(git_commit *commit, void *data, size_t len, unsigned int
 	return GIT_SUCCESS;
 }
 
-int git_commit__parse(git_commit *commit)
+int git_commit__parse(git_commit *commit, git_odb_object *obj)
 {
-	assert(commit && commit->object.source.open);
-	return commit_parse_buffer(commit,
-			commit->object.source.raw.data, commit->object.source.raw.len, COMMIT_BASIC_PARSE);
-}
-
-int git_commit__parse_full(git_commit *commit)
-{
-	int error;
-
-	if (commit->full_parse)
-		return GIT_SUCCESS;
-
-	if ((error = git_object__source_open((git_object *)commit)) < GIT_SUCCESS)
-		return error;
-
-	error = commit_parse_buffer(commit,
-			commit->object.source.raw.data, commit->object.source.raw.len, COMMIT_FULL_PARSE);
-
-	git_object__source_close((git_object *)commit);
-
-	commit->full_parse = 1;
-	return error;
+	assert(commit);
+	return commit_parse_buffer(commit, obj->raw.data, obj->raw.len);
 }
 
-
-
-#define GIT_COMMIT_GETTER(_rvalue, _name) \
-	const _rvalue git_commit_##_name(git_commit *commit) \
+#define GIT_COMMIT_GETTER(_rvalue, _name, _return) \
+	_rvalue git_commit_##_name(git_commit *commit) \
 	{\
 		assert(commit); \
-		if (commit->_name) \
-			return commit->_name; \
-		if (!commit->object.in_memory) \
-			git_commit__parse_full(commit); \
-		return commit->_name; \
+		return _return; \
 	}
 
-#define CHECK_FULL_PARSE() \
-	if (!commit->object.in_memory && !commit->full_parse)\
-		git_commit__parse_full(commit); 
+GIT_COMMIT_GETTER(const git_signature *, author, commit->author)
+GIT_COMMIT_GETTER(const git_signature *, committer, commit->committer)
+GIT_COMMIT_GETTER(const char *, message, commit->message)
+GIT_COMMIT_GETTER(const char *, message_short, commit->message_short)
+GIT_COMMIT_GETTER(git_time_t, time, commit->committer->when.time)
+GIT_COMMIT_GETTER(int, time_offset, commit->committer->when.offset)
+GIT_COMMIT_GETTER(unsigned int, parentcount, commit->parent_oids.length)
 
-const git_tree *git_commit_tree(git_commit *commit)
-{
-	assert(commit);
 
-	if (!commit->object.in_memory && commit->tree == NULL)
-		git_commit__parse_full(commit);
-
-	GIT_OBJECT_INCREF(commit->object.repo, commit->tree);
-	return commit->tree;
-}
-
-GIT_COMMIT_GETTER(git_signature *, author)
-GIT_COMMIT_GETTER(git_signature *, committer)
-GIT_COMMIT_GETTER(char *, message)
-GIT_COMMIT_GETTER(char *, message_short)
-
-time_t git_commit_time(git_commit *commit)
-{
-	assert(commit && commit->committer);
-	return commit->committer->when.time;
-}
-
-int git_commit_time_offset(git_commit *commit)
-{
-	assert(commit && commit->committer);
-	return commit->committer->when.offset;
-}
-
-unsigned int git_commit_parentcount(git_commit *commit)
+int git_commit_tree(git_tree **tree_out, git_commit *commit)
 {
 	assert(commit);
-	return commit->parents.length;
+	return git_tree_lookup(tree_out, commit->object.repo, &commit->tree_oid);
 }
 
-git_commit *git_commit_parent(git_commit *commit, unsigned int n)
+int git_commit_parent(git_commit **parent, git_commit *commit, unsigned int n)
 {
-	git_commit *parent;
-
+	git_oid *parent_oid;
 	assert(commit);
 
-	parent = git_vector_get(&commit->parents, n);
-	GIT_OBJECT_INCREF(commit->object.repo, parent);
-	return parent;
-}
-
-void git_commit_set_tree(git_commit *commit, git_tree *tree)
-{
-	assert(commit && tree);
-	commit->object.modified = 1;
-	CHECK_FULL_PARSE();
-
-	GIT_OBJECT_DECREF(commit->object.repo, commit->tree);
-	GIT_OBJECT_INCREF(commit->object.repo, tree);
-	commit->tree = tree;
-}
-
-void git_commit_set_author(git_commit *commit, const git_signature *author_sig)
-{
-	assert(commit && author_sig);
-	commit->object.modified = 1;
-	CHECK_FULL_PARSE();
-
-	git_signature_free(commit->author);
-	commit->author = git_signature_dup(author_sig);
-}
-
-void git_commit_set_committer(git_commit *commit, const git_signature *committer_sig)
-{
-	assert(commit && committer_sig);
-	commit->object.modified = 1;
-	CHECK_FULL_PARSE();
-
-	git_signature_free(commit->committer);
-	commit->committer = git_signature_dup(committer_sig);
-}
-
-void git_commit_set_message(git_commit *commit, const char *message)
-{
-	const char *line_end;
-	size_t message_len;
-
-	commit->object.modified = 1;
-	CHECK_FULL_PARSE();
-
-	if (commit->message)
-		free(commit->message);
-
-	if (commit->message_short)
-		free(commit->message_short);
+	parent_oid = git_vector_get(&commit->parent_oids, n);
+	if (parent_oid == NULL)
+		return GIT_ENOTFOUND;
 
-	commit->message = git__strdup(message);
-
-	/* Short message */
-	if((line_end = strchr(message, '\n')) == NULL) {
-		commit->message_short = git__strdup(message);
-		return;
-	}
-
-	message_len = line_end - message;
-
-	commit->message_short = git__malloc(message_len + 1);
-	memcpy(commit->message_short, message, message_len);
-	commit->message_short[message_len] = 0;
+	return git_commit_lookup(parent, commit->object.repo, parent_oid);
 }
 
-int git_commit_add_parent(git_commit *commit, git_commit *new_parent)
-{
-	assert(commit && new_parent);
 
-	CHECK_FULL_PARSE();
-	commit->object.modified = 1;
-	GIT_OBJECT_INCREF(commit->object.repo, new_parent);
-	return git_vector_insert(&commit->parents, new_parent);
-}
diff --git a/src/commit.h b/src/commit.h
index b53ee9b23..3d15c5044 100644
--- a/src/commit.h
+++ b/src/commit.h
@@ -11,22 +11,17 @@
 struct git_commit {
 	git_object object;
 
-	git_vector parents;
+	git_vector parent_oids;
+	git_oid tree_oid;
 
-	git_tree *tree;
 	git_signature *author;
 	git_signature *committer;
 
 	char *message;
 	char *message_short;
-
-	unsigned full_parse:1;
 };
 
 void git_commit__free(git_commit *c);
-int git_commit__parse(git_commit *commit);
-int git_commit__parse_full(git_commit *commit);
-
-int git_commit__writeback(git_commit *commit, git_odb_source *src);
+int git_commit__parse(git_commit *commit, git_odb_object *obj);
 
 #endif
diff --git a/src/common.h b/src/common.h
index 1ca00471b..5ad878e26 100644
--- a/src/common.h
+++ b/src/common.h
@@ -11,9 +11,6 @@
 #include "git2/thread-utils.h"
 #include "cc-compat.h"
 
-#ifdef GIT_HAS_PTHREAD
-# include <pthread.h>
-#endif
 #ifdef GIT_HAVE_INTTYPES_H
 # include <inttypes.h>
 #endif
@@ -34,16 +31,21 @@
 # include <windows.h>
 # include "msvc-compat.h"
 # include "mingw-compat.h"
+# ifdef GIT_THREADS
+#  include "win32/pthread.h"
+#endif
 
 # define snprintf _snprintf
 
 typedef SSIZE_T ssize_t;
 
 #else
-
 # include <unistd.h>
 # include <arpa/inet.h>
 
+# ifdef GIT_THREADS
+#  include <pthread.h>
+# endif
 #endif
 
 #include "git2/common.h"
diff --git a/src/delta-apply.h b/src/delta-apply.h
index 642442de0..36c5cc60d 100644
--- a/src/delta-apply.h
+++ b/src/delta-apply.h
@@ -1,6 +1,8 @@
 #ifndef INCLUDE_delta_apply_h__
 #define INCLUDE_delta_apply_h__
 
+#include "odb.h"
+
 /**
  * Apply a git binary delta to recover the original content.
  *
diff --git a/src/errors.c b/src/errors.c
index 1dc54f945..5e59f8205 100644
--- a/src/errors.c
+++ b/src/errors.c
@@ -27,7 +27,9 @@ static struct {
 	{GIT_EPACKEDREFSCORRUPTED, "The pack-refs file is either corrupted of its format is not currently supported"},
 	{GIT_EINVALIDPATH, "The path is invalid" },
 	{GIT_EREVWALKOVER, "The revision walker is empty; there are no more commits left to iterate"},
-	{GIT_EINVALIDREFSTATE, "The state of the reference is not valid"}
+	{GIT_EINVALIDREFSTATE, "The state of the reference is not valid"},
+	{GIT_ENOTIMPLEMENTED, "This feature has not been implemented yet"},
+	{GIT_EEXISTS, "A reference with this name already exists"}
 };
 
 const char *git_strerror(int num)
diff --git a/src/filebuf.c b/src/filebuf.c
index 4fc4f1486..dff9373f6 100644
--- a/src/filebuf.c
+++ b/src/filebuf.c
@@ -77,44 +77,81 @@ void git_filebuf_cleanup(git_filebuf *file)
 	if (file->fd >= 0)
 		gitfo_close(file->fd);
 
-	if (gitfo_exists(file->path_lock) == GIT_SUCCESS)
+	if (file->path_lock && gitfo_exists(file->path_lock) == GIT_SUCCESS)
 		gitfo_unlink(file->path_lock);
 
 	if (file->digest)
 		git_hash_free_ctx(file->digest);
 
 	free(file->buffer);
+	free(file->z_buf);
 
-#ifdef GIT_FILEBUF_THREADS
-	free(file->buffer_back);
-#endif
+	deflateEnd(&file->zs);
 
 	free(file->path_original);
 	free(file->path_lock);
 }
 
-static int flush_buffer(git_filebuf *file)
+GIT_INLINE(int) flush_buffer(git_filebuf *file)
 {
-	int result = GIT_SUCCESS;
+	int result = file->write(file, file->buffer, file->buf_pos);
+	file->buf_pos = 0;
+	return result;
+}
 
-	if (file->buf_pos > 0) {
-		result = gitfo_write(file->fd, file->buffer, file->buf_pos);
-		if (file->digest)
-			git_hash_update(file->digest, file->buffer, file->buf_pos);
+static int write_normal(git_filebuf *file, const void *source, size_t len)
+{
+	int result = 0;
 
-		file->buf_pos = 0;
+	if (len > 0) {
+		result = gitfo_write(file->fd, (void *)source, len);
+		if (file->digest)
+			git_hash_update(file->digest, source, len);
 	}
 
 	return result;
 }
 
+static int write_deflate(git_filebuf *file, const void *source, size_t len)
+{
+	int result = Z_OK;
+	z_stream *zs = &file->zs;
+
+	if (len > 0 || file->flush_mode == Z_FINISH) {
+		zs->next_in = (void *)source;
+		zs->avail_in = len;
+
+		do {
+			int have;
+
+			zs->next_out = file->z_buf;
+			zs->avail_out = file->buf_size;
+
+            result = deflate(zs, file->flush_mode);
+            assert(result != Z_STREAM_ERROR);
+
+            have = file->buf_size - zs->avail_out;
+
+			if (gitfo_write(file->fd, file->z_buf, have) < GIT_SUCCESS)
+				return GIT_EOSERR;
+
+        } while (zs->avail_out == 0);
+
+		assert(zs->avail_in == 0);
+
+		if (file->digest)
+			git_hash_update(file->digest, source, len);
+	}
+
+	return GIT_SUCCESS;
+}
+
 int git_filebuf_open(git_filebuf *file, const char *path, int flags)
 {
 	int error;
 	size_t path_len;
 
-	if (file == NULL || path == NULL)
-		return GIT_ERROR;
+	assert(file && path);
 
 	memset(file, 0x0, sizeof(git_filebuf));
 
@@ -122,46 +159,87 @@ int git_filebuf_open(git_filebuf *file, const char *path, int flags)
 	file->buf_pos = 0;
 	file->fd = -1;
 
-	path_len = strlen(path);
-
-	file->path_original = git__strdup(path);
-	if (file->path_original == NULL) {
+	/* Allocate the main cache buffer */
+	file->buffer = git__malloc(file->buf_size);
+	if (file->buffer == NULL){
 		error = GIT_ENOMEM;
 		goto cleanup;
 	}
 
-	file->path_lock = git__malloc(path_len + GIT_FILELOCK_EXTLENGTH);
-	if (file->path_lock == NULL) {
-		error = GIT_ENOMEM;
-		goto cleanup;
+	/* If we are hashing on-write, allocate a new hash context */
+	if (flags & GIT_FILEBUF_HASH_CONTENTS) {
+		if ((file->digest = git_hash_new_ctx()) == NULL) {
+			error = GIT_ENOMEM;
+			goto cleanup;
+		}
 	}
 
-	memcpy(file->path_lock, file->path_original, path_len);
-	memcpy(file->path_lock + path_len, GIT_FILELOCK_EXTENSION, GIT_FILELOCK_EXTLENGTH);
+	/* If we are deflating on-write, */
+	if (flags & GIT_FILEBUF_DEFLATE_CONTENTS) {
 
-	file->buffer = git__malloc(file->buf_size);
-	if (file->buffer == NULL){
-		error = GIT_ENOMEM;
-		goto cleanup;
-	}
+		/* Initialize the ZLib stream */
+		if (deflateInit(&file->zs, Z_DEFAULT_COMPRESSION) != Z_OK) {
+			error = GIT_EZLIB;
+			goto cleanup;
+		}
 
-#ifdef GIT_FILEBUF_THREADS
-	file->buffer_back = git__malloc(file->buf_size);
-	if (file->buffer_back == NULL){
-		error = GIT_ENOMEM;
-		goto cleanup;
+		/* Allocate the Zlib cache buffer */
+		file->z_buf = git__malloc(file->buf_size);
+		if (file->z_buf == NULL){
+			error = GIT_ENOMEM;
+			goto cleanup;
+		}
+
+		/* Never flush */
+		file->flush_mode = Z_NO_FLUSH;
+		file->write = &write_deflate;
+	} else {
+		file->write = &write_normal;
 	}
-#endif
 
-	if (flags & GIT_FILEBUF_HASH_CONTENTS) {
-		if ((file->digest = git_hash_new_ctx()) == NULL) {
+	/* If we are writing to a temp file */
+	if (flags & GIT_FILEBUF_TEMPORARY) {
+		char tmp_path[GIT_PATH_MAX];
+
+		/* Open the file as temporary for locking */
+		file->fd = gitfo_mktemp(tmp_path, path); 
+		if (file->fd < 0) {
+			error = GIT_EOSERR;
+			goto cleanup;
+		}
+
+		/* No original path */
+		file->path_original = NULL;
+		file->path_lock = git__strdup(tmp_path);
+
+		if (file->path_lock == NULL) {
 			error = GIT_ENOMEM;
 			goto cleanup;
 		}
-	}
+	} else {
+		path_len = strlen(path);
 
-	if ((error = lock_file(file, flags)) < GIT_SUCCESS)
-		goto cleanup;
+		/* Save the original path of the file */
+		file->path_original = git__strdup(path);
+		if (file->path_original == NULL) {
+			error = GIT_ENOMEM;
+			goto cleanup;
+		}
+
+		/* create the locking path by appending ".lock" to the original */
+		file->path_lock = git__malloc(path_len + GIT_FILELOCK_EXTLENGTH);
+		if (file->path_lock == NULL) {
+			error = GIT_ENOMEM;
+			goto cleanup;
+		}
+
+		memcpy(file->path_lock, file->path_original, path_len);
+		memcpy(file->path_lock + path_len, GIT_FILELOCK_EXTENSION, GIT_FILELOCK_EXTLENGTH);
+
+		/* open the file for locking */
+		if ((error = lock_file(file, flags)) < GIT_SUCCESS)
+			goto cleanup;
+	}
 
 	return GIT_SUCCESS;
 
@@ -187,10 +265,25 @@ int git_filebuf_hash(git_oid *oid, git_filebuf *file)
 	return GIT_SUCCESS;
 }
 
+int git_filebuf_commit_at(git_filebuf *file, const char *path)
+{
+	free(file->path_original);
+	file->path_original = git__strdup(path);
+	if (file->path_original == NULL)
+		return GIT_ENOMEM;
+
+	return git_filebuf_commit(file);
+}
+
 int git_filebuf_commit(git_filebuf *file)
 {
 	int error;
 
+	/* tmp file cannot be commited */
+	if (file->path_original == NULL)
+		return GIT_EOSERR;
+
+	file->flush_mode = Z_FINISH;
 	if ((error = flush_buffer(file)) < GIT_SUCCESS)
 		goto cleanup;
 
@@ -204,16 +297,16 @@ cleanup:
 	return error;
 }
 
-GIT_INLINE(void) add_to_cache(git_filebuf *file, void *buf, size_t len)
+GIT_INLINE(void) add_to_cache(git_filebuf *file, const void *buf, size_t len)
 {
 	memcpy(file->buffer + file->buf_pos, buf, len);
 	file->buf_pos += len;
 }
 
-int git_filebuf_write(git_filebuf *file, void *buff, size_t len)
+int git_filebuf_write(git_filebuf *file, const void *buff, size_t len)
 {
 	int error;
-	unsigned char *buf = buff;
+	const unsigned char *buf = buff;
 
 	for (;;) {
 		size_t space_left = file->buf_size - file->buf_pos;
@@ -237,9 +330,9 @@ int git_filebuf_write(git_filebuf *file, void *buff, size_t len)
 
 		/* write too-large chunks immediately */
 		if (len > file->buf_size) {
-			error = gitfo_write(file->fd, buf, len);
-			if (file->digest)
-				git_hash_update(file->digest, buf, len);
+			error = file->write(file, buf, len);
+			if (error < GIT_SUCCESS)
+				return error;
 		}
 	}
 }
diff --git a/src/filebuf.h b/src/filebuf.h
index 9db615fbd..37cb36784 100644
--- a/src/filebuf.h
+++ b/src/filebuf.h
@@ -3,14 +3,17 @@
 
 #include "fileops.h"
 #include "hash.h"
+#include "git2/zlib.h"
 
 #ifdef GIT_THREADS
 #	define GIT_FILEBUF_THREADS
 #endif
 
-#define GIT_FILEBUF_HASH_CONTENTS 0x1
-#define GIT_FILEBUF_APPEND 0x2
-#define GIT_FILEBUF_FORCE 0x4
+#define GIT_FILEBUF_HASH_CONTENTS		(1 << 0)
+#define GIT_FILEBUF_APPEND				(1 << 2)
+#define GIT_FILEBUF_FORCE				(1 << 3)
+#define GIT_FILEBUF_TEMPORARY			(1 << 4)
+#define GIT_FILEBUF_DEFLATE_CONTENTS	(1 << 5)
 
 #define GIT_FILELOCK_EXTENSION ".lock\0"
 #define GIT_FILELOCK_EXTLENGTH 6
@@ -19,12 +22,16 @@ struct git_filebuf {
 	char *path_original;
 	char *path_lock;
 
+	int (*write)(struct git_filebuf *file,
+			const void *source, size_t len);
+
 	git_hash_ctx *digest;
 
 	unsigned char *buffer;
-#ifdef GIT_FILEBUF_THREADS
-	unsigned char *buffer_back;
-#endif
+	unsigned char *z_buf;
+
+	z_stream zs;
+	int flush_mode;
 
 	size_t buf_size, buf_pos;
 	git_file fd;
@@ -32,12 +39,13 @@ struct git_filebuf {
 
 typedef struct git_filebuf git_filebuf;
 
-int git_filebuf_write(git_filebuf *lock, void *buff, size_t len);
+int git_filebuf_write(git_filebuf *lock, const void *buff, size_t len);
 int git_filebuf_reserve(git_filebuf *file, void **buff, size_t len);
 int git_filebuf_printf(git_filebuf *file, const char *format, ...);
 
 int git_filebuf_open(git_filebuf *lock, const char *path, int flags);
 int git_filebuf_commit(git_filebuf *lock);
+int git_filebuf_commit_at(git_filebuf *lock, const char *path);
 void git_filebuf_cleanup(git_filebuf *lock);
 int git_filebuf_hash(git_oid *oid, git_filebuf *file);
 
diff --git a/src/fileops.c b/src/fileops.c
index 76e689e8a..5dd4a3806 100644
--- a/src/fileops.c
+++ b/src/fileops.c
@@ -2,13 +2,13 @@
 #include "fileops.h"
 #include <ctype.h>
 
-static int force_path(const char *to)
+int gitfo_mkdir_2file(const char *file_path)
 {
 	const int mode = 0755; /* or 0777 ? */
 	int error = GIT_SUCCESS;
 	char target_folder_path[GIT_PATH_MAX];
 
-	error = git__dirname_r(target_folder_path, sizeof(target_folder_path), to);
+	error = git__dirname_r(target_folder_path, sizeof(target_folder_path), file_path);
 	if (error < GIT_SUCCESS)
 		return error;
 
@@ -25,6 +25,27 @@ static int force_path(const char *to)
 	return GIT_SUCCESS;
 }
 
+int gitfo_mktemp(char *path_out, const char *filename)
+{
+	int fd;
+
+	strcpy(path_out, filename);
+	strcat(path_out, "_git2_XXXXXX");
+
+#if defined(_MSC_VER)
+	/* FIXME: there may be race conditions when multi-threading
+	 * with the library */
+	if (_mktemp_s(path_out, GIT_PATH_MAX) != 0)
+		return GIT_EOSERR;
+
+	fd = gitfo_creat(path_out, 0744);
+#else
+	fd = mkstemp(path_out);
+#endif
+
+	return fd >= 0 ? fd : GIT_EOSERR;
+}
+
 int gitfo_open(const char *path, int flags)
 {
 	int fd = open(path, flags | O_BINARY);
@@ -39,7 +60,7 @@ int gitfo_creat(const char *path, int mode)
 
 int gitfo_creat_force(const char *path, int mode)
 {
-	if (force_path(path) < GIT_SUCCESS)
+	if (gitfo_mkdir_2file(path) < GIT_SUCCESS)
 		return GIT_EOSERR;
 
 	return gitfo_creat(path, mode);
@@ -117,6 +138,7 @@ int gitfo_isdir(const char *path)
 
 int gitfo_exists(const char *path)
 {
+	assert(path);
 	return access(path, F_OK);
 }
 
@@ -181,7 +203,7 @@ int gitfo_mv(const char *from, const char *to)
 	 * file exists, the `rename` call fails. This is as
 	 * close as it gets with the Win32 API.
 	 */
-	return MoveFileEx(from, to, MOVEFILE_REPLACE_EXISTING) ? GIT_SUCCESS : GIT_EOSERR;
+	return MoveFileEx(from, to, MOVEFILE_REPLACE_EXISTING | MOVEFILE_COPY_ALLOWED) ? GIT_SUCCESS : GIT_EOSERR;
 #else
 	/* Don't even try this on Win32 */
 	if (!link(from, to)) {
@@ -198,7 +220,7 @@ int gitfo_mv(const char *from, const char *to)
 
 int gitfo_mv_force(const char *from, const char *to)
 {
-	if (force_path(to) < GIT_SUCCESS)
+	if (gitfo_mkdir_2file(to) < GIT_SUCCESS)
 		return GIT_EOSERR;
 
 	return gitfo_mv(from, to);
@@ -361,22 +383,29 @@ int gitfo_dirent(
 	return GIT_SUCCESS;
 }
 
-#ifdef GIT_WIN32
 
-static int is_windows_rooted_path(const char *path)
+int retrieve_path_root_offset(const char *path)
 {
+	int offset = 0;
+
+#ifdef GIT_WIN32
+
 	/* Does the root of the path look like a windows drive ? */
 	if (isalpha(path[0]) && (path[1] == ':'))
-		return GIT_SUCCESS;
+		offset += 2;
+
+#endif
+
+	if (*(path + offset) == '/')
+		return offset;
 
 	return GIT_ERROR;
 }
 
-#endif
 
 int gitfo_mkdir_recurs(const char *path, int mode)
 {
-	int error;
+	int error, root_path_offset;
 	char *pp, *sp;
     char *path_copy = git__strdup(path);
 
@@ -386,12 +415,9 @@ int gitfo_mkdir_recurs(const char *path, int mode)
 	error = GIT_SUCCESS;
 	pp = path_copy;
 
-#ifdef GIT_WIN32
-
-	if (!is_windows_rooted_path(pp))
-		pp += 2; /* Skip the drive name (eg. C: or D:) */
-
-#endif
+	root_path_offset = retrieve_path_root_offset(pp);
+	if (root_path_offset > 0)
+		pp += root_path_offset; /* On Windows, will skip the drive name (eg. C: or D:) */
 
     while (error == GIT_SUCCESS && (sp = strchr(pp, '/')) != 0) {
 		if (sp != pp && gitfo_isdir(path_copy) < GIT_SUCCESS) {
@@ -417,8 +443,12 @@ int gitfo_mkdir_recurs(const char *path, int mode)
 
 static int retrieve_previous_path_component_start(const char *path)
 {
-	int offset, len, start = 0;
-	
+	int offset, len, root_offset, start = 0;
+
+	root_offset = retrieve_path_root_offset(path);
+	if (root_offset > -1)
+		start += root_offset;
+
 	len = strlen(path);
 	offset = len - 1;
 
@@ -430,7 +460,7 @@ static int retrieve_previous_path_component_start(const char *path)
 	if (path[offset] == '/')
 		offset--;
 
-	if (offset < 0)
+	if (offset < root_offset)
 		return GIT_ERROR;
 
 	while (offset > start && path[offset-1] != '/') {
@@ -440,15 +470,25 @@ static int retrieve_previous_path_component_start(const char *path)
 	return offset;
 }
 
-int gitfo_prettify_dir_path(char *buffer_out, const char *path)
+int gitfo_prettify_dir_path(char *buffer_out, size_t size, const char *path)
 {
-	int len = 0, segment_len, only_dots;
+	int len = 0, segment_len, only_dots, root_path_offset, error = GIT_SUCCESS;
 	char *current;
 	const char *buffer_out_start, *buffer_end;
 
-	buffer_out_start = buffer_out;
 	current = (char *)path;
 	buffer_end = path + strlen(path);
+	buffer_out_start = buffer_out;
+
+	root_path_offset = retrieve_path_root_offset(path);
+	if (root_path_offset < 0) {
+		error = gitfo_getcwd(buffer_out, size);
+		if (error < GIT_SUCCESS)
+			return error;
+
+		len = strlen(buffer_out);
+		buffer_out += len;
+	}
 
 	while (current < buffer_end) {
 		/* Prevent multiple slashes from being added to the output */
@@ -461,7 +501,7 @@ int gitfo_prettify_dir_path(char *buffer_out, const char *path)
 		segment_len = 0;
 
 		/* Copy path segment to the output */
-		while (current < buffer_end && *current !='/')
+		while (current < buffer_end && *current != '/')
 		{
 			only_dots &= (*current == '.');
 			*buffer_out++ = *current++;
@@ -486,7 +526,9 @@ int gitfo_prettify_dir_path(char *buffer_out, const char *path)
 
 			*buffer_out ='\0';
 			len = retrieve_previous_path_component_start(buffer_out_start);
-			if (len < GIT_SUCCESS)
+
+			/* Are we escaping out of the root dir? */
+			if (len < 0)
 				return GIT_EINVALIDPATH;
 
 			buffer_out = (char *)buffer_out_start + len;
@@ -494,7 +536,7 @@ int gitfo_prettify_dir_path(char *buffer_out, const char *path)
 		}
 
 		/* Guard against potential multiple dot path traversal (cf http://cwe.mitre.org/data/definitions/33.html) */
-		if (only_dots &&segment_len > 0)
+		if (only_dots && segment_len > 0)
 			return GIT_EINVALIDPATH;
 
 		*buffer_out++ = '/';
@@ -506,20 +548,24 @@ int gitfo_prettify_dir_path(char *buffer_out, const char *path)
 	return GIT_SUCCESS;
 }
 
-int gitfo_prettify_file_path(char *buffer_out, const char *path)
+int gitfo_prettify_file_path(char *buffer_out, size_t size, const char *path)
 {
 	int error, path_len, i;
 	const char* pattern = "/..";
 
 	path_len = strlen(path);
 
+	/* Let's make sure the filename isn't empty nor a dot */
+	if (path_len == 0 || (path_len == 1 && *path == '.'))
+		return GIT_EINVALIDPATH;
+
 	/* Let's make sure the filename doesn't end with "/", "/." or "/.." */
 	for (i = 1; path_len > i && i < 4; i++) {
 		if (!strncmp(path + path_len - i, pattern, i))
 			return GIT_EINVALIDPATH;
 	}
 
-	error =  gitfo_prettify_dir_path(buffer_out, path);
+	error =  gitfo_prettify_dir_path(buffer_out, size, path);
 	if (error < GIT_SUCCESS)
 		return error;
 
@@ -551,3 +597,34 @@ int gitfo_cmp_path(const char *name1, int len1, int isdir1,
 	return 0;
 }
 
+static void posixify_path(char *path)
+{
+	while (*path) {
+		if (*path == '\\')
+			*path = '/';
+
+		path++;
+	}
+}
+
+int gitfo_getcwd(char *buffer_out, size_t size)
+{
+	char *cwd_buffer;
+
+	assert(buffer_out && size > 0);
+
+#ifdef GIT_WIN32
+	cwd_buffer = _getcwd(buffer_out, size);
+#else
+	cwd_buffer = getcwd(buffer_out, size); //TODO: Fixme. Ensure the required headers are correctly included
+#endif
+
+	if (cwd_buffer == NULL)
+		return GIT_EOSERR;
+
+	posixify_path(buffer_out);
+
+	git__joinpath(buffer_out, buffer_out, "");	//Ensure the path ends with a trailing slash
+
+	return GIT_SUCCESS;
+}
diff --git a/src/fileops.h b/src/fileops.h
index 5aa302b54..6e0fd9d14 100644
--- a/src/fileops.h
+++ b/src/fileops.h
@@ -58,8 +58,10 @@ extern int gitfo_exists(const char *path);
 extern int gitfo_open(const char *path, int flags);
 extern int gitfo_creat(const char *path, int mode);
 extern int gitfo_creat_force(const char *path, int mode);
+extern int gitfo_mktemp(char *path_out, const char *filename);
 extern int gitfo_isdir(const char *path);
 extern int gitfo_mkdir_recurs(const char *path, int mode);
+extern int gitfo_mkdir_2file(const char *path);
 #define gitfo_close(fd) close(fd)
 
 extern int gitfo_read(git_file fd, void *buf, size_t cnt);
@@ -142,6 +144,8 @@ extern int gitfo_close_cached(gitfo_cache *ioc);
 extern int gitfo_cmp_path(const char *name1, int len1, int isdir1,
 		const char *name2, int len2, int isdir2);
 
+extern int gitfo_getcwd(char *buffer_out, size_t size);
+
 /**
  * Clean up a provided absolute or relative directory path.
  * 
@@ -159,12 +163,13 @@ extern int gitfo_cmp_path(const char *name1, int len1, int isdir1,
  * the file system perspective.
  *
  * @param buffer_out buffer to populate with the normalized path.
+ * @param size buffer size.
  * @param path directory path to clean up.
  * @return
  * - GIT_SUCCESS on success;
  * - GIT_ERROR when the input path is invalid or escapes the current directory.
  */
-GIT_EXTERN(int) gitfo_prettify_dir_path(char *buffer_out, const char *path);
+int gitfo_prettify_dir_path(char *buffer_out, size_t size, const char *path);
 
 /**
  * Clean up a provided absolute or relative file path.
@@ -181,11 +186,13 @@ GIT_EXTERN(int) gitfo_prettify_dir_path(char *buffer_out, const char *path);
  * the file system perspective.
  *
  * @param buffer_out buffer to populate with the normalized path.
+ * @param size buffer size.
  * @param path file path to clean up.
  * @return
  * - GIT_SUCCESS on success;
  * - GIT_ERROR when the input path is invalid or escapes the current directory.
  */
-GIT_EXTERN(int) gitfo_prettify_file_path(char *buffer_out, const char *path);
+int gitfo_prettify_file_path(char *buffer_out, size_t size, const char *path);
 
+int retrieve_path_root_offset(const char *path);
 #endif /* INCLUDE_fileops_h__ */
diff --git a/src/hashtable.c b/src/hashtable.c
index c36d8a8e6..ee6d3a461 100644
--- a/src/hashtable.c
+++ b/src/hashtable.c
@@ -184,6 +184,8 @@ int git_hashtable_insert2(git_hashtable *self, const void *key, void *value, voi
 	int hash_id;
 	git_hashtable_node *node;
 
+	assert(self && self->nodes);
+
 	*old_value = NULL;
 
 	for (hash_id = 0; hash_id < GIT_HASHTABLE_HASHES; ++hash_id) {
@@ -218,6 +220,8 @@ void *git_hashtable_lookup(git_hashtable *self, const void *key)
 	int hash_id;
 	git_hashtable_node *node;
 
+	assert(self && self->nodes);
+
 	for (hash_id = 0; hash_id < GIT_HASHTABLE_HASHES; ++hash_id) {
 		node = node_with_hash(self, key, hash_id);
 		if (node->key && self->key_equal(key, node->key) == 0)
@@ -232,6 +236,8 @@ int git_hashtable_remove(git_hashtable *self, const void *key)
 	int hash_id;
 	git_hashtable_node *node;
 
+	assert(self && self->nodes);
+
 	for (hash_id = 0; hash_id < GIT_HASHTABLE_HASHES; ++hash_id) {
 		node = node_with_hash(self, key, hash_id);
 		if (node->key && self->key_equal(key, node->key) == 0) {
diff --git a/src/index.c b/src/index.c
index 95e56b7d5..6a31dd5cb 100644
--- a/src/index.c
+++ b/src/index.c
@@ -74,7 +74,7 @@ struct entry_short {
 	uint32_t file_size;
 	git_oid oid;
 	uint16_t flags;
-	char path[1]; /* arbritrary length */
+	char path[1]; /* arbitrary length */
 };
 
 struct entry_long {
@@ -89,7 +89,7 @@ struct entry_long {
 	git_oid oid;
 	uint16_t flags;
 	uint16_t flags_extended;
-	char path[1]; /* arbritrary length */
+	char path[1]; /* arbitrary length */
 };
 
 /* local declarations */
@@ -148,7 +148,7 @@ static int index_initialize(git_index **index_out, git_repository *owner, const
 		index->on_disk = 1;
 
 	*index_out = index;
-	return GIT_SUCCESS;
+	return git_index_read(index);
 }
 
 int git_index_open_bare(git_index **index_out, const char *index_path)
@@ -312,8 +312,8 @@ int git_index_add(git_index *index, const char *rel_path, int stage)
 
 	memset(&entry, 0x0, sizeof(git_index_entry));
 
-	entry.ctime.seconds = st.st_ctime;
-	entry.mtime.seconds = st.st_mtime;
+	entry.ctime.seconds = (git_time_t)st.st_ctime;
+	entry.mtime.seconds = (git_time_t)st.st_mtime;
 	/* entry.mtime.nanoseconds = st.st_mtimensec; */
 	/* entry.ctime.nanoseconds = st.st_ctimensec; */
 	entry.dev= st.st_rdev;
@@ -324,7 +324,7 @@ int git_index_add(git_index *index, const char *rel_path, int stage)
 	entry.file_size = st.st_size;
 
 	/* write the blob to disk and get the oid */
-	if ((error = git_blob_writefile(&entry.oid, index->repository, full_path)) < GIT_SUCCESS)
+	if ((error = git_blob_create_fromfile(&entry.oid, index->repository, rel_path)) < GIT_SUCCESS)
 		return error;
 
 	entry.flags |= (stage << GIT_IDXENTRY_STAGESHIFT);
@@ -491,10 +491,10 @@ static size_t read_entry(git_index_entry *dest, const void *buffer, size_t buffe
 
 	source = (const struct entry_short *)(buffer);
 
-	dest->ctime.seconds = (time_t)ntohl(source->ctime.seconds);
-	dest->ctime.nanoseconds = (time_t)ntohl(source->ctime.nanoseconds);
-	dest->mtime.seconds = (time_t)ntohl(source->mtime.seconds);
-	dest->mtime.nanoseconds = (time_t)ntohl(source->mtime.nanoseconds);
+	dest->ctime.seconds = (git_time_t)ntohl(source->ctime.seconds);
+	dest->ctime.nanoseconds = ntohl(source->ctime.nanoseconds);
+	dest->mtime.seconds = (git_time_t)ntohl(source->mtime.seconds);
+	dest->mtime.nanoseconds = ntohl(source->mtime.nanoseconds);
 	dest->dev = ntohl(source->dev);
 	dest->ino = ntohl(source->ino);
 	dest->mode = ntohl(source->mode);
diff --git a/src/object.c b/src/object.c
index 7891893a0..0572663eb 100644
--- a/src/object.c
+++ b/src/object.c
@@ -66,153 +66,6 @@ static struct {
 	{ "REF_DELTA", 0, 0	}
 };
 
-/*
- * Object source methods
- *
- * Abstract buffer methods that allow the writeback system
- * to prepare the contents of any git file in-memory before
- * writing them to disk.
- */
-static int source_resize(git_odb_source *src)
-{
-	size_t write_offset, new_size;
-	void *new_data;
-
-	write_offset = (size_t)((char *)src->write_ptr - (char *)src->raw.data);
-
-	new_size = src->raw.len * 2;
-	if ((new_data = git__malloc(new_size)) == NULL)
-		return GIT_ENOMEM;
-
-	memcpy(new_data, src->raw.data, src->written_bytes);
-	free(src->raw.data);
-
-	src->raw.data = new_data;
-	src->raw.len = new_size;
-	src->write_ptr = (char *)new_data + write_offset;
-
-	return GIT_SUCCESS;
-}
-
-int git__source_printf(git_odb_source *source, const char *format, ...)
-{
-	va_list arglist;
-	int len;
-
-	assert(source->open && source->write_ptr);
-
-	va_start(arglist, format);
-
-	len = vsnprintf(source->write_ptr, source->raw.len - source->written_bytes, format, arglist);
-
-	while (source->written_bytes + len >= source->raw.len) {
-		if (source_resize(source) < GIT_SUCCESS)
-			return GIT_ENOMEM;
-
-		len = vsnprintf(source->write_ptr, source->raw.len - source->written_bytes, format, arglist);
-	}
-
-	source->write_ptr = (char *)source->write_ptr + len;
-	source->written_bytes += len;
-
-	return GIT_SUCCESS;
-}
-
-int git__source_write(git_odb_source *source, const void *bytes, size_t len)
-{
-	assert(source);
-
-	assert(source->open && source->write_ptr);
-
-	while (source->written_bytes + len >= source->raw.len) {
-		if (source_resize(source) < GIT_SUCCESS)
-			return GIT_ENOMEM;
-	}
-
-	memcpy(source->write_ptr, bytes, len);
-	source->write_ptr = (char *)source->write_ptr + len;
-	source->written_bytes += len;
-
-	return GIT_SUCCESS;
-}
-
-static void prepare_write(git_object *object)
-{
-	if (object->source.write_ptr != NULL || object->source.open)
-		git_object__source_close(object);
-
-	/* TODO: proper size calculation */
-	object->source.raw.data = git__malloc(OBJECT_BASE_SIZE);
-	object->source.raw.len = OBJECT_BASE_SIZE;
-
-	object->source.write_ptr = object->source.raw.data;
-	object->source.written_bytes = 0;
-
-	object->source.open = 1;
-}
-
-static int write_back(git_object *object)
-{
-	int error;
-	git_oid new_id;
-
-	assert(object);
-
-	assert(object->source.open);
-	assert(object->modified);
-
-	object->source.raw.len = object->source.written_bytes;
-
-	if ((error = git_odb_write(&new_id, object->repo->db, &object->source.raw)) < GIT_SUCCESS)
-		return error;
-
-	if (object->in_memory) {
-		int idx = git_vector_search(&object->repo->memory_objects, object);
-		git_vector_remove(&object->repo->memory_objects, idx);
-	} else {
-		git_hashtable_remove(object->repo->objects, &object->id);
-	}
-
-	git_oid_cpy(&object->id, &new_id);
-	git_hashtable_insert(object->repo->objects, &object->id, object);
-
-	object->source.write_ptr = NULL;
-	object->source.written_bytes = 0;
-
-	object->modified = 0;
-	object->in_memory = 0;
-
-	git_object__source_close(object);
-	return GIT_SUCCESS;
-}
-
-int git_object__source_open(git_object *object)
-{
-	int error;
-
-	assert(object && !object->in_memory);
-
-	if (object->source.open)
-		git_object__source_close(object);
-
-	error = git_odb_read(&object->source.raw, object->repo->db, &object->id);
-	if (error < GIT_SUCCESS)
-		return error;
-
-	object->source.open = 1;
-	return GIT_SUCCESS;
-}
-
-void git_object__source_close(git_object *object)
-{
-	assert(object);
-
-	if (object->source.open) {
-		git_rawobj_close(&object->source.raw);
-		object->source.open = 0;
-	}
-}
-
 static int create_object(git_object **object_out, git_otype type)
 {
 	git_object *object = NULL;
@@ -225,43 +78,19 @@ static int create_object(git_object **object_out, git_otype type)
 	case GIT_OBJ_COMMIT:
 	case GIT_OBJ_TAG:
 	case GIT_OBJ_BLOB:
+	case GIT_OBJ_TREE:
 		object = git__malloc(git_object__size(type));
 		if (object == NULL)
 			return GIT_ENOMEM;
 		memset(object, 0x0, git_object__size(type));
 		break;
-		
-	case GIT_OBJ_TREE:
-		object = (git_object *)git_tree__new();
-		if (object == NULL)
-			return GIT_ENOMEM;
-		break;
 
 	default:
 		return GIT_EINVALIDTYPE;
 	}
 
-	*object_out = object;
-	return GIT_SUCCESS;
-}
-
-int git_object_new(git_object **object_out, git_repository *repo, git_otype type)
-{
-	git_object *object = NULL;
-	int error;
-
-	assert(object_out && repo);
-
-	if ((error = create_object(&object, type)) < GIT_SUCCESS)
-		return error;
-
-	object->repo = repo;
-	object->in_memory = 1;
-	object->modified = 1;
-
-	object->source.raw.type = type;
+	object->type = type;
 
-	object->refcount++;
 	*object_out = object;
 	return GIT_SUCCESS;
 }
@@ -269,122 +98,77 @@ int git_object_new(git_object **object_out, git_repository *repo, git_otype type
 int git_object_lookup(git_object **object_out, git_repository *repo, const git_oid *id, git_otype type)
 {
 	git_object *object = NULL;
-	git_rawobj obj_file;
+	git_odb_object *odb_obj;
 	int error = GIT_SUCCESS;
 
 	assert(repo && object_out && id);
 
-	object = git_hashtable_lookup(repo->objects, id);
+	object = git_cache_get(&repo->objects, id);
 	if (object != NULL) {
+		if (type != GIT_OBJ_ANY && type != object->type)
+			return GIT_EINVALIDTYPE;
+
 		*object_out = object;
-		GIT_OBJECT_INCREF(repo, object);
 		return GIT_SUCCESS;
 	}
 
-	error = git_odb_read(&obj_file, repo->db, id);
+	error = git_odb_read(&odb_obj, repo->db, id);
 	if (error < GIT_SUCCESS)
 		return error;
 
-	if (type != GIT_OBJ_ANY && type != obj_file.type) {
-		git_rawobj_close(&obj_file);
+	if (type != GIT_OBJ_ANY && type != odb_obj->raw.type) {
+		git_odb_object_close(odb_obj);
 		return GIT_EINVALIDTYPE;
 	}
 
-	type = obj_file.type;
+	type = odb_obj->raw.type;
 
 	if ((error = create_object(&object, type)) < GIT_SUCCESS)
 		return error;
 
 	/* Initialize parent object */
-	git_oid_cpy(&object->id, id);
+	git_oid_cpy(&object->cached.oid, id);
 	object->repo = repo;
-	memcpy(&object->source.raw, &obj_file, sizeof(git_rawobj));
-	object->source.open = 1;
 
 	switch (type) {
 	case GIT_OBJ_COMMIT:
-		error = git_commit__parse((git_commit *)object);
+		error = git_commit__parse((git_commit *)object, odb_obj);
 		break;
 
 	case GIT_OBJ_TREE:
-		error = git_tree__parse((git_tree *)object);
+		error = git_tree__parse((git_tree *)object, odb_obj);
 		break;
 
 	case GIT_OBJ_TAG:
-		error = git_tag__parse((git_tag *)object);
+		error = git_tag__parse((git_tag *)object, odb_obj);
 		break;
 
 	case GIT_OBJ_BLOB:
-		error = git_blob__parse((git_blob *)object);
+		error = git_blob__parse((git_blob *)object, odb_obj);
 		break;
 
 	default:
 		break;
 	}
 
+	git_odb_object_close(odb_obj);
+
 	if (error < GIT_SUCCESS) {
 		git_object__free(object);
 		return error;
 	}
 
-	git_object__source_close(object);
-	git_hashtable_insert(repo->objects, &object->id, object);
-
-	GIT_OBJECT_INCREF(repo, object);
-	*object_out = object;
+	*object_out = git_cache_try_store(&repo->objects, object);
 	return GIT_SUCCESS;
 }
 
-int git_object_write(git_object *object)
+void git_object__free(void *_obj)
 {
-	int error;
-	git_odb_source *source;
-
-	assert(object);
+	git_object *object = (git_object *)_obj;
 
-	if (object->modified == 0)
-		return GIT_SUCCESS;
-
-	prepare_write(object);
-	source = &object->source;
-
-	switch (source->raw.type) {
-	case GIT_OBJ_COMMIT:
-		error = git_commit__writeback((git_commit *)object, source);
-		break;
-
-	case GIT_OBJ_TREE:
-		error = git_tree__writeback((git_tree *)object, source);
-		break;
-
-	case GIT_OBJ_TAG:
-		error = git_tag__writeback((git_tag *)object, source);
-		break;
-
-	case GIT_OBJ_BLOB:
-		error = git_blob__writeback((git_blob *)object, source);
-		break;
-
-	default:
-		error = GIT_ERROR;
-		break;
-	}
-
-	if (error < GIT_SUCCESS) {
-		git_object__source_close(object);
-		return error;
-	}
-
-	return write_back(object);
-}
-
-void git_object__free(git_object *object)
-{
 	assert(object);
 
-	git_object__source_close(object);
-
-	switch (object->source.raw.type) {
+	switch (object->type) {
 	case GIT_OBJ_COMMIT:
 		git_commit__free((git_commit *)object);
 		break;
@@ -412,34 +196,19 @@ void git_object_close(git_object *object)
 	if (object == NULL)
 		return;
 
-	if (--object->refcount <= 0) {
-		if (object->repo != NULL) {
-			if (object->in_memory) {
-				int idx = git_vector_search(&object->repo->memory_objects, object);
-				git_vector_remove(&object->repo->memory_objects, idx);
-			} else {
-				git_hashtable_remove(object->repo->objects, &object->id);
-			}
-		}
-
-		git_object__free(object);
-	}
+	git_cached_obj_decref((git_cached_obj *)object, git_object__free);
 }
 
 const git_oid *git_object_id(const git_object *obj)
 {
 	assert(obj);
-
-	if (obj->in_memory)
-		return NULL;
-
-	return &obj->id;
+	return &obj->cached.oid;
 }
 
 git_otype git_object_type(const git_object *obj)
 {
 	assert(obj);
-	return obj->source.raw.type;
+	return obj->type;
 }
 
 git_repository *git_object_owner(const git_object *obj)
diff --git a/src/odb.c b/src/odb.c
index 2013ac24c..33d5468d9 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -87,54 +87,67 @@ int git_odb__hash_obj(git_oid *id, char *hdr, size_t n, int *len, git_rawobj *ob
 	return GIT_SUCCESS;
 }
 
-void git_rawobj_close(git_rawobj *obj)
-{
-	free(obj->data);
-	obj->data = NULL;
-}
 
-int git_rawobj_hash(git_oid *id, git_rawobj *obj)
+static git_odb_object *new_odb_object(const git_oid *oid, git_rawobj *source)
 {
-	char hdr[64];
-	int  hdrlen;
+	git_odb_object *object = git__malloc(sizeof(git_odb_object));
+	memset(object, 0x0, sizeof(git_odb_object));
 
-	assert(id && obj);
+	git_oid_cpy(&object->cached.oid, oid);
+	memcpy(&object->raw, source, sizeof(git_rawobj));
 
-	return git_odb__hash_obj(id, hdr, sizeof(hdr), &hdrlen, obj);
+	return object;
 }
 
-int git_odb__inflate_buffer(void *in, size_t inlen, void *out, size_t outlen)
+static void free_odb_object(void *o)
 {
-	z_stream zs;
-	int status = Z_OK;
-
-	memset(&zs, 0x0, sizeof(zs));
+	git_odb_object *object = (git_odb_object *)o;
 
-	zs.next_out  = out;
-	zs.avail_out = outlen;
-
-	zs.next_in  = in;
-	zs.avail_in = inlen;
-
-	if (inflateInit(&zs) < Z_OK)
-		return GIT_ERROR;
+	if (object != NULL) {
+		free(object->raw.data);
+		free(object);
+	}
+}
 
-	while (status == Z_OK)
-		status = inflate(&zs, Z_FINISH);
+const git_oid *git_odb_object_id(git_odb_object *object)
+{
+	return &object->cached.oid;
+}
 
-	inflateEnd(&zs);
+const void *git_odb_object_data(git_odb_object *object)
+{
+	return object->raw.data;
+}
 
-	if ((status != Z_STREAM_END) /*|| (zs.avail_in != 0) */)
-		return GIT_ERROR;
+size_t git_odb_object_size(git_odb_object *object)
+{
+	return object->raw.len;
+}
 
-	if (zs.total_out != outlen)
-		return GIT_ERROR;
+git_otype git_odb_object_type(git_odb_object *object)
+{
+	return object->raw.type;
+}
 
-	return GIT_SUCCESS;
+void git_odb_object_close(git_odb_object *object)
+{
+	git_cached_obj_decref((git_cached_obj *)object, &free_odb_object);
 }
 
+int git_odb_hash(git_oid *id, const void *data, size_t len, git_otype type)
+{
+	char hdr[64];
+	int  hdrlen;
+	git_rawobj raw;
+
+	assert(id);
 
+	raw.data = (void *)data;
+	raw.len = len;
+	raw.type = type;
 
+	return git_odb__hash_obj(id, hdr, sizeof(hdr), &hdrlen, &raw);
+}
 
 
 /***********************************************************
@@ -162,6 +175,8 @@ int git_odb_new(git_odb **out)
 	if (!db)
 		return GIT_ENOMEM;
 
+	git_cache_init(&db->cache, GIT_DEFAULT_CACHE_SIZE, &free_odb_object);
+
 	if (git_vector_init(&db->backends, 4, backend_sort_cmp) < 0) {
 		free(db);
 		return GIT_ENOMEM;
@@ -306,16 +321,23 @@ void git_odb_close(git_odb *db)
 	}
 
 	git_vector_free(&db->backends);
+	git_cache_free(&db->cache);
 	free(db);
 }
 
 int git_odb_exists(git_odb *db, const git_oid *id)
 {
+	git_odb_object *object;
 	unsigned int i;
 	int found = 0;
 
 	assert(db && id);
 
+	if ((object = git_cache_get(&db->cache, id)) != NULL) {
+		git_odb_object_close(object);
+		return 1;
+	}
+
 	for (i = 0; i < db->backends.length && !found; ++i) {
 		backend_internal *internal = git_vector_get(&db->backends, i);
 		git_odb_backend *b = internal->backend;
@@ -327,19 +349,27 @@ int git_odb_exists(git_odb *db, const git_oid *id)
 	return found;
 }
 
-int git_odb_read_header(git_rawobj *out, git_odb *db, const git_oid *id)
+int git_odb_read_header(size_t *len_p, git_otype *type_p, git_odb *db, const git_oid *id)
 {
 	unsigned int i;
 	int error = GIT_ENOTFOUND;
+	git_odb_object *object;
 
-	assert(out && db && id);
+	assert(db && id);
+
+	if ((object = git_cache_get(&db->cache, id)) != NULL) {
+		*len_p = object->raw.len;
+		*type_p = object->raw.type;
+		git_odb_object_close(object);
+		return GIT_SUCCESS;
+	}
 
 	for (i = 0; i < db->backends.length && error < 0; ++i) {
 		backend_internal *internal = git_vector_get(&db->backends, i);
 		git_odb_backend *b = internal->backend;
 
 		if (b->read_header != NULL)
-			error = b->read_header(out, b, id);
+			error = b->read_header(len_p, type_p, b, id);
 	}
 
 	/*
@@ -347,37 +377,50 @@ int git_odb_read_header(git_rawobj *out, git_odb *db, const git_oid *id)
 	 * try reading the whole object and freeing the contents
 	 */
 	if (error < 0) {
-		error = git_odb_read(out, db, id);
-		git_rawobj_close(out);
+		if ((error = git_odb_read(&object, db, id)) < GIT_SUCCESS)
+			return error;
+
+		*len_p = object->raw.len;
+		*type_p = object->raw.len;
+		git_odb_object_close(object);
 	}
 
-	return error;
+	return GIT_SUCCESS;
 }
 
-int git_odb_read(git_rawobj *out, git_odb *db, const git_oid *id)
+int git_odb_read(git_odb_object **out, git_odb *db, const git_oid *id)
 {
 	unsigned int i;
 	int error = GIT_ENOTFOUND;
+	git_rawobj raw;
 
 	assert(out && db && id);
 
+	*out = git_cache_get(&db->cache, id);
+	if (*out != NULL)
+		return GIT_SUCCESS;
+
 	for (i = 0; i < db->backends.length && error < 0; ++i) {
 		backend_internal *internal = git_vector_get(&db->backends, i);
 		git_odb_backend *b = internal->backend;
 
 		if (b->read != NULL)
-			error = b->read(out, b, id);
+			error = b->read(&raw.data, &raw.len, &raw.type, b, id);
+	}
+
+	if (error == GIT_SUCCESS) {
+		*out = git_cache_try_store(&db->cache, new_odb_object(id, &raw));
 	}
 
 	return error;
 }
 
-int git_odb_write(git_oid *id, git_odb *db, git_rawobj *obj)
+int git_odb_write(git_oid *oid, git_odb *db, const void *data, size_t len, git_otype type)
 {
 	unsigned int i;
 	int error = GIT_ERROR;
 
-	assert(obj && db && id);
+	assert(oid && db);
 
 	for (i = 0; i < db->backends.length && error < 0; ++i) {
 		backend_internal *internal = git_vector_get(&db->backends, i);
@@ -388,7 +431,60 @@ int git_odb_write(git_oid *id, git_odb *db, git_rawobj *obj)
 			continue;
 
 		if (b->write != NULL)
-			error = b->write(id, b, obj);
+			error = b->write(oid, b, data, len, type);
+	}
+
+	/* if no backends were able to write the object directly, we try a streaming
+	 * write to the backends; just write the whole object into the stream in one
+	 * push */
+	if (error < GIT_SUCCESS) {
+		git_odb_stream *stream;
+
+		if ((error = git_odb_open_wstream(&stream, db, len, type)) == GIT_SUCCESS) {
+			stream->write(stream, data, len);
+			error = stream->finalize_write(oid, stream);
+			stream->free(stream);
+		}
+	}
+
+	return error;
+}
+
+int git_odb_open_wstream(git_odb_stream **stream, git_odb *db, size_t size, git_otype type)
+{
+	unsigned int i;
+	int error = GIT_ERROR;
+
+	assert(stream && db);
+
+	for (i = 0; i < db->backends.length && error < 0; ++i) {
+		backend_internal *internal = git_vector_get(&db->backends, i);
+		git_odb_backend *b = internal->backend;
+
+		/* we don't write in alternates! */
+		if (internal->is_alternate)
+			continue;
+
+		if (b->writestream != NULL)
+			error = b->writestream(stream, b, size, type);
+	}
+
+	return error;
+}
+
+int git_odb_open_rstream(git_odb_stream **stream, git_odb *db, const git_oid *oid) 
+{
+	unsigned int i;
+	int error = GIT_ERROR;
+
+	assert(stream && db);
+
+	for (i = 0; i < db->backends.length && error < 0; ++i) {
+		backend_internal *internal = git_vector_get(&db->backends, i);
+		git_odb_backend *b = internal->backend;
+
+		if (b->readstream != NULL)
+			error = b->readstream(stream, b, oid);
 	}
 
 	return error;
diff --git a/src/odb.h b/src/odb.h
index c3d0a17ab..f3685834e 100644
--- a/src/odb.h
+++ b/src/odb.h
@@ -3,15 +3,31 @@
 
 #include "git2/odb.h"
 #include "git2/oid.h"
+#include "git2/types.h"
 
 #include "vector.h"
+#include "cache.h"
 
+/* DO NOT EXPORT */
+typedef struct {
+	void *data;          /**< Raw, decompressed object data. */
+	size_t len;          /**< Total number of bytes in data. */
+	git_otype type;      /**< Type of this object. */
+} git_rawobj;
+
+/* EXPORT */
+struct git_odb_object {
+	git_cached_obj cached;
+	git_rawobj raw;
+};
+
+/* EXPORT */
 struct git_odb {
 	void *_internal;
 	git_vector backends;
+	git_cache cache;
 };
 
 int git_odb__hash_obj(git_oid *id, char *hdr, size_t n, int *len, git_rawobj *obj);
-int git_odb__inflate_buffer(void *in, size_t inlen, void *out, size_t outlen);
 
 #endif
diff --git a/src/odb_loose.c b/src/odb_loose.c
index 4e2d9a639..8ee01cd2c 100644
--- a/src/odb_loose.c
+++ b/src/odb_loose.c
@@ -30,14 +30,22 @@
 #include "hash.h"
 #include "odb.h"
 #include "delta-apply.h"
+#include "filebuf.h"
 
 #include "git2/odb_backend.h"
+#include "git2/types.h"
 
 typedef struct {  /* object header data */
 	git_otype type;  /* object type */
 	size_t    size;  /* object size */
 } obj_hdr;
 
+typedef struct {
+	git_odb_stream stream;
+	git_filebuf fbuf;
+	int finished;
+} loose_writestream;
+
 typedef struct loose_backend {
 	git_odb_backend parent;
 
@@ -53,38 +61,6 @@ typedef struct loose_backend {
  *
  ***********************************************************/
 
-static int make_temp_file(git_file *fd, char *tmp, size_t n, char *file)
-{
-	char *template = "/tmp_obj_XXXXXX";
-	size_t tmplen = strlen(template);
-	int dirlen;
-
-	if ((dirlen = git__dirname_r(tmp, n, file)) < 0)
-		return GIT_ERROR;
-
-	if ((dirlen + tmplen) >= n)
-		return GIT_ERROR;
-
-	strcpy(tmp + dirlen, (dirlen) ? template : template + 1);
-
-	*fd = gitfo_mkstemp(tmp);
-	if (*fd < 0 && dirlen) {
-		/* create directory if it doesn't exist */
-		tmp[dirlen] = '\0';
-		if ((gitfo_exists(tmp) < 0) && gitfo_mkdir(tmp, 0755))
-			return GIT_ERROR;
-		/* try again */
-		strcpy(tmp + dirlen, template);
-		*fd = gitfo_mkstemp(tmp);
-	}
-	if (*fd < 0)
-		return GIT_ERROR;
-
-	return GIT_SUCCESS;
-}
-
-
-
 static size_t object_file_name(char *name, size_t n, char *dir, const git_oid *id)
 {
 	size_t len = strlen(dir);
@@ -236,72 +212,44 @@ static int finish_inflate(z_stream *s)
 	return GIT_SUCCESS;
 }
 
-static int deflate_buf(z_stream *s, void *in, size_t len, int flush)
+static int is_zlib_compressed_data(unsigned char *data)
 {
-	int status = Z_OK;
+	unsigned int w;
 
-	set_stream_input(s, in, len);
-	while (status == Z_OK) {
-		status = deflate(s, flush);
-		if (s->avail_in == 0)
-			break;
-	}
-	return status;
+	w = ((unsigned int)(data[0]) << 8) + data[1];
+	return data[0] == 0x78 && !(w % 31);
 }
 
-static int deflate_obj(gitfo_buf *buf, char *hdr, int hdrlen, git_rawobj *obj, int level)
+static int inflate_buffer(void *in, size_t inlen, void *out, size_t outlen)
 {
 	z_stream zs;
-	int status;
-	size_t size;
-
-	assert(buf && !buf->data && hdr && obj);
-	assert(level == Z_DEFAULT_COMPRESSION || (level >= 0 && level <= 9));
+	int status = Z_OK;
 
-	buf->data = NULL;
-	buf->len  = 0;
-	init_stream(&zs, NULL, 0);
+	memset(&zs, 0x0, sizeof(zs));
 
-	if (deflateInit(&zs, level) < Z_OK)
-		return GIT_ERROR;
+	zs.next_out  = out;
+	zs.avail_out = outlen;
 
-	size = deflateBound(&zs, hdrlen + obj->len);
+	zs.next_in  = in;
+	zs.avail_in = inlen;
 
-	if ((buf->data = git__malloc(size)) == NULL) {
-		deflateEnd(&zs);
+	if (inflateInit(&zs) < Z_OK)
 		return GIT_ERROR;
-	}
 
-	set_stream_output(&zs, buf->data, size);
-
-	/* compress the header */
-	status = deflate_buf(&zs, hdr, hdrlen, Z_NO_FLUSH);
+	while (status == Z_OK)
+		status = inflate(&zs, Z_FINISH);
 
-	/* if header compressed OK, compress the object */
-	if (status == Z_OK)
-		status = deflate_buf(&zs, obj->data, obj->len, Z_FINISH);
+	inflateEnd(&zs);
 
-	if (status != Z_STREAM_END) {
-		deflateEnd(&zs);
-		free(buf->data);
-		buf->data = NULL;
+	if ((status != Z_STREAM_END) /*|| (zs.avail_in != 0) */)
 		return GIT_ERROR;
-	}
 
-	buf->len = zs.total_out;
-	deflateEnd(&zs);
+	if (zs.total_out != outlen)
+		return GIT_ERROR;
 
 	return GIT_SUCCESS;
 }
 
-static int is_zlib_compressed_data(unsigned char *data)
-{
-	unsigned int w;
-
-	w = ((unsigned int)(data[0]) << 8) + data[1];
-	return data[0] == 0x78 && !(w % 31);
-}
-
 static void *inflate_tail(z_stream *s, void *hb, size_t used, obj_hdr *hdr)
 {
 	unsigned char *buf, *head = hb;
@@ -371,7 +319,7 @@ static int inflate_packlike_loose_disk_obj(git_rawobj *out, gitfo_buf *obj)
 
 	in  = ((unsigned char *)obj->data) + used;
 	len = obj->len - used;
-	if (git_odb__inflate_buffer(in, len, buf, hdr.size)) {
+	if (inflate_buffer(in, len, buf, hdr.size)) {
 		free(buf);
 		return GIT_ERROR;
 	}
@@ -505,37 +453,6 @@ cleanup:
 	return error;
 }
 
-static int write_obj(gitfo_buf *buf, git_oid *id, loose_backend *backend)
-{
-	char file[GIT_PATH_MAX];
-	char temp[GIT_PATH_MAX];
-	git_file fd;
-
-	if (object_file_name(file, sizeof(file), backend->objects_dir, id))
-		return GIT_EOSERR;
-
-	if (make_temp_file(&fd, temp, sizeof(temp), file) < 0)
-		return GIT_EOSERR;
-
-	if (gitfo_write(fd, buf->data, buf->len) < 0) {
-		gitfo_close(fd);
-		gitfo_unlink(temp);
-		return GIT_EOSERR;
-	}
-
-	if (backend->fsync_object_files)
-		gitfo_fsync(fd);
-	gitfo_close(fd);
-	gitfo_chmod(temp, 0444);
-
-	if (gitfo_mv(temp, file) < 0) {
-		gitfo_unlink(temp);
-		return GIT_EOSERR;
-	}
-
-	return GIT_SUCCESS;
-}
-
 static int locate_object(char *object_location, loose_backend *backend, const git_oid *oid)
 {
 	object_file_name(object_location, GIT_PATH_MAX, backend->objects_dir, oid);
@@ -558,29 +475,44 @@ static int locate_object(char *object_location, loose_backend *backend, const gi
  *
  ***********************************************************/
 
-int loose_backend__read_header(git_rawobj *obj, git_odb_backend *backend, const git_oid *oid)
+int loose_backend__read_header(size_t *len_p, git_otype *type_p, git_odb_backend *backend, const git_oid *oid)
 {
 	char object_path[GIT_PATH_MAX];
+	git_rawobj raw;
+	int error;
 
-	assert(obj && backend && oid);
+	assert(backend && oid);
 
 	if (locate_object(object_path, (loose_backend *)backend, oid) < 0)
 		return GIT_ENOTFOUND;
 
-	return read_header_loose(obj, object_path);
-}
+	if ((error = read_header_loose(&raw, object_path)) < GIT_SUCCESS)
+		return error;
 
+	*len_p = raw.len;
+	*type_p = raw.type;
+	return GIT_SUCCESS;
+}
 
-int loose_backend__read(git_rawobj *obj, git_odb_backend *backend, const git_oid *oid)
+int loose_backend__read(void **buffer_p, size_t *len_p, git_otype *type_p, git_odb_backend *backend, const git_oid *oid)
 {
 	char object_path[GIT_PATH_MAX];
+	git_rawobj raw;
+	int error;
 
-	assert(obj && backend && oid);
+	assert(backend && oid);
 
 	if (locate_object(object_path, (loose_backend *)backend, oid) < 0)
 		return GIT_ENOTFOUND;
 
-	return read_loose(obj, object_path);
+	if ((error = read_loose(&raw, object_path)) < GIT_SUCCESS)
+		return error;
+
+	*buffer_p = raw.data;
+	*len_p = raw.len;
+	*type_p = raw.type;
+
+	return GIT_SUCCESS;
 }
 
 int loose_backend__exists(git_odb_backend *backend, const git_oid *oid)
@@ -592,32 +524,106 @@ int loose_backend__exists(git_odb_backend *backend, const git_oid *oid)
 	return locate_object(object_path, (loose_backend *)backend, oid) == GIT_SUCCESS;
 }
 
+int loose_backend__stream_fwrite(git_oid *oid, git_odb_stream *_stream)
+{
+	loose_writestream *stream = (loose_writestream *)_stream;
+	loose_backend *backend = (loose_backend *)_stream->backend;
+
+	int error;
+	char final_path[GIT_PATH_MAX];
+
+	if ((error = git_filebuf_hash(oid, &stream->fbuf)) < GIT_SUCCESS)
+		return error;
+
+	if (object_file_name(final_path, sizeof(final_path), backend->objects_dir, oid))
+		return GIT_ENOMEM;
+
+	if ((error = gitfo_mkdir_2file(final_path)) < GIT_SUCCESS)
+		return error;
+
+	stream->finished = 1;
+	return git_filebuf_commit_at(&stream->fbuf, final_path);
+}
+
+int loose_backend__stream_write(git_odb_stream *_stream, const char *data, size_t len)
+{
+	loose_writestream *stream = (loose_writestream *)_stream;
+	return git_filebuf_write(&stream->fbuf, data, len);
+}
 
-int loose_backend__write(git_oid *id, git_odb_backend *_backend, git_rawobj *obj)
+void loose_backend__stream_free(git_odb_stream *_stream)
 {
-	char hdr[64];
+	loose_writestream *stream = (loose_writestream *)_stream;
+
+	if (!stream->finished)
+		git_filebuf_cleanup(&stream->fbuf);
+
+	free(stream);
+}
+
+static int format_object_header(char *hdr, size_t n, size_t obj_len, git_otype obj_type)
+{
+	const char *type_str = git_object_type2string(obj_type);
+	int len = snprintf(hdr, n, "%s %"PRIuZ, type_str, obj_len);
+
+	assert(len > 0);             /* otherwise snprintf() is broken  */
+	assert(((size_t) len) < n);  /* otherwise the caller is broken! */
+
+	if (len < 0 || ((size_t) len) >= n)
+		return GIT_ERROR;
+	return len+1;
+}
+
+int loose_backend__stream(git_odb_stream **stream_out, git_odb_backend *_backend, size_t length, git_otype type)
+{
+	loose_backend *backend;
+	loose_writestream *stream;
+
+	char hdr[64], tmp_path[GIT_PATH_MAX];
 	int  hdrlen;
-	gitfo_buf buf = GITFO_BUF_INIT;
 	int error;
-	loose_backend *backend;
 
-	assert(id && _backend && obj);
+	assert(_backend);
 
 	backend = (loose_backend *)_backend;
+	*stream_out = NULL;
 
-	if ((error = git_odb__hash_obj(id, hdr, sizeof(hdr), &hdrlen, obj)) < 0)
-		return error;
+	hdrlen = format_object_header(hdr, sizeof(hdr), length, type);
+	if (hdrlen < GIT_SUCCESS)
+		return GIT_EOBJCORRUPTED;
+
+	stream = git__calloc(1, sizeof(loose_writestream));
+	if (stream == NULL)
+		return GIT_ENOMEM;
+
+	stream->stream.backend = _backend;
+	stream->stream.read = NULL; /* read only */
+	stream->stream.write = &loose_backend__stream_write;
+	stream->stream.finalize_write = &loose_backend__stream_fwrite;
+	stream->stream.free = &loose_backend__stream_free;
+	stream->stream.mode = GIT_STREAM_WRONLY;
 
-	if (git_odb_exists(_backend->odb, id))
-		return GIT_SUCCESS;
+	git__joinpath(tmp_path, backend->objects_dir, "tmp_object");
 
-	if ((error = deflate_obj(&buf, hdr, hdrlen, obj, backend->object_zlib_level)) < 0)
+	error = git_filebuf_open(&stream->fbuf, tmp_path,
+		GIT_FILEBUF_HASH_CONTENTS |
+		GIT_FILEBUF_DEFLATE_CONTENTS |
+		GIT_FILEBUF_TEMPORARY);
+
+	if (error < GIT_SUCCESS) {
+		free(stream);
 		return error;
+	}
 
-	error = write_obj(&buf, id, backend);
+	error = stream->stream.write((git_odb_stream *)stream, hdr, hdrlen);
+	if (error < GIT_SUCCESS) {
+		git_filebuf_cleanup(&stream->fbuf);
+		free(stream);
+		return error;
+	}
 
-	gitfo_free_buf(&buf);
-	return error;
+	*stream_out = (git_odb_stream *)stream;
+	return GIT_SUCCESS;
 }
 
 void loose_backend__free(git_odb_backend *_backend)
@@ -649,7 +655,7 @@ int git_odb_backend_loose(git_odb_backend **backend_out, const char *objects_dir
 
 	backend->parent.read = &loose_backend__read;
 	backend->parent.read_header = &loose_backend__read_header;
-	backend->parent.write = &loose_backend__write;
+	backend->parent.writestream = &loose_backend__stream;
 	backend->parent.exists = &loose_backend__exists;
 	backend->parent.free = &loose_backend__free;
 
diff --git a/src/odb_pack.c b/src/odb_pack.c
index 664b00139..8c527bcf3 100644
--- a/src/odb_pack.c
+++ b/src/odb_pack.c
@@ -33,503 +33,625 @@
 
 #include "git2/odb_backend.h"
 
-/** First 4 bytes of a pack-*.idx file header.
- *
- * Note this header exists only in idx v2 and later.  The idx v1
- * file format does not have a magic sequence at the front, and
- * must be detected by the first four bytes *not* being this value
- * and the first 8 bytes matching the following expression:
+#define DEFAULT_WINDOW_SIZE \
+	(sizeof(void*) >= 8 \
+		?  1 * 1024 * 1024 * 1024 \
+		: 32 * 1024 * 1024)
+
+#define DEFAULT_MAPPED_LIMIT \
+	((1024L * 1024L) * (sizeof(void*) >= 8 ? 8192 : 256))
+
+#define PACK_SIGNATURE 0x5041434b	/* "PACK" */
+#define PACK_VERSION 2
+#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
+struct pack_header {
+	uint32_t hdr_signature;
+	uint32_t hdr_version;
+	uint32_t hdr_entries;
+};
+
+/*
+ * The first four bytes of index formats later than version 1 should
+ * start with this signature, as all older git binaries would find this
+ * value illegal and abort reading the file.
  *
- *   uint32_t *fanout = ... the file data at offset 0 ...
- *   ntohl(fanout[0]) < ntohl(fanout[1])
+ * This is the case because the number of objects in a packfile
+ * cannot exceed 1,431,660,000 as every object would need at least
+ * 3 bytes of data and the overall packfile cannot exceed 4 GiB with
+ * version 1 of the index file due to the offsets limited to 32 bits.
+ * Clearly the signature exceeds this maximum.
  *
- * The value chosen here for PACK_TOC is such that the above
- * cannot be true for an idx v1 file.
+ * Very old git binaries will also compare the first 4 bytes to the
+ * next 4 bytes in the index and abort with a "non-monotonic index"
+ * error if the second 4 byte word is smaller than the first 4
+ * byte word.  This would be true in the proposed future index
+ * format as idx_signature would be greater than idx_version.
  */
-#define PACK_TOC 0xff744f63 /* -1tOc */
+#define PACK_IDX_SIGNATURE 0xff744f63	/* "\377tOc" */
 
-/** First 4 bytes of a pack-*.pack file header. */
-#define PACK_SIG 0x5041434b /* PACK */
+struct pack_idx_header {
+	uint32_t idx_signature;
+	uint32_t idx_version;
+};
 
-#define GIT_PACK_NAME_MAX (5 + 40 + 1)
+struct pack_window {
+	struct pack_window *next;
+	git_map window_map;
+	off_t offset;
+	unsigned int last_used;
+	unsigned int inuse_cnt;
+};
 
-struct pack_backend;
+struct pack_file {
+	struct pack_window *windows;
+	off_t pack_size;
 
-typedef struct {
-	uint32_t      n;
-	unsigned char *oid;
-	git_off_t     offset;
-	git_off_t     size;
-} index_entry;
+	git_map index_map;
 
-typedef struct { /* '.pack' file header */
-	uint32_t sig; /* PACK_SIG */
-	uint32_t ver; /* pack version */
-	uint32_t cnt; /* object count */
-} pack_hdr;
+	uint32_t num_objects;
+	uint32_t num_bad_objects;
+	git_oid *bad_object_sha1; /* array of git_oid */
 
-typedef struct git_pack {
-	struct pack_backend *backend;
-	git_lck lock;
-
-	/** Functions to access idx_map. */
-	int (*idx_search)(
-		uint32_t *,
-		struct git_pack *,
-		const git_oid *);
-	int (*idx_search_offset)(
-		uint32_t *,
-		struct git_pack *,
-		git_off_t);
-	int (*idx_get)(
-		index_entry *,
-		struct git_pack *,
-		uint32_t n);
-
-	/** The .idx file, mapped into memory. */
-	git_file idx_fd;
-	git_map idx_map;
-	uint32_t *im_fanout;
-	unsigned char *im_oid;
-	uint32_t *im_crc;
-	uint32_t *im_offset32;
-	uint32_t *im_offset64;
-	uint32_t *im_off_idx;
-	uint32_t *im_off_next;
-
-	/** Number of objects in this pack. */
-	uint32_t obj_cnt;
-
-	/** File descriptor for the .pack file. */
-	git_file pack_fd;
-
-	/** Memory map of the pack's contents */
-	git_map pack_map;
-
-	/** The size of the .pack file. */
-	git_off_t pack_size;
-
-	/** The mtime of the .pack file. */
-	time_t pack_mtime;
-
-	/** Number of git_packlist we appear in. */
-	unsigned int refcnt;
-
-	/** Number of active users of the idx_map data. */
-	unsigned int idxcnt;
-	unsigned
-		invalid:1 /* the pack is unable to be read by libgit2 */
-		;
-
-	/** Name of the pack file(s), without extension ("pack-abc"). */
-	char pack_name[GIT_PACK_NAME_MAX];
-} git_pack;
-
-typedef struct {
-	size_t n_packs;
-	unsigned int refcnt;
-	git_pack *packs[GIT_FLEX_ARRAY];
-} git_packlist;
-
-typedef struct pack_backend {
-	git_odb_backend parent;
+	int index_version;
+	git_time_t mtime;
+	int pack_fd;
+	unsigned pack_local:1, pack_keep:1;
+	git_oid sha1;
 
-	git_lck lock;
-	char *objects_dir;
-	git_packlist *packlist;
-} pack_backend;
+	/* something like ".git/objects/pack/xxxxx.pack" */
+	char pack_name[GIT_FLEX_ARRAY]; /* more */
+};
 
+struct pack_entry {
+	off_t offset;
+	git_oid sha1;
+	struct pack_file *p;
+};
 
-typedef struct pack_location {
-	git_pack *ptr;
-	uint32_t n;
-} pack_location;
+struct pack__dirent {
+	struct pack_backend *backend;
+	int is_pack_local;
+};
 
-static int pack_stat(git_pack *p);
-static int pack_openidx(git_pack *p);
-static void pack_decidx(git_pack *p);
-static int read_pack_hdr(pack_hdr *out, git_file fd);
-static int check_pack_hdr(git_pack *p);
-static int check_pack_sha1(git_pack *p);
-static int open_pack(git_pack *p);
+struct pack_backend {
+	git_odb_backend parent;
+	git_vector packs;
+	struct pack_file *last_found;
 
+	size_t window_size; /* needs default value */
 
-static int pack_openidx_map(git_pack *p);
-static int pack_openidx_v1(git_pack *p);
-static int pack_openidx_v2(git_pack *p);
+	size_t mapped_limit; /* needs default value */
+	size_t peak_mapped;
+	size_t mapped;
 
+	size_t used_ctr;
 
-GIT_INLINE(uint32_t) decode32(void *b)
-{
-	return ntohl(*((uint32_t *)b));
-}
+	unsigned int peak_open_windows;
+	unsigned int open_windows;
 
-GIT_INLINE(uint64_t) decode64(void *b)
-{
-	uint32_t *p = b;
-	return (((uint64_t)ntohl(p[0])) << 32) | ntohl(p[1]);
-}
+	unsigned int mmap_calls;
+};
+
+/**
+ * The wonderful tale of a Packed Object lookup query
+ * ===================================================
+ *   A riveting and epic story of epicness and ASCII
+ *          art, presented by yours truly,
+ *               Sir Vicent of Marti
+ *
+ *
+ *	Chapter 1: Once upon a time...
+ *	Initialization of the Pack Backend
+ *	--------------------------------------------------
+ *
+ *	# git_odb_backend_pack
+ *	| Creates the pack backend structure, initializes the
+ *	| callback pointers to our default read() and exist() methods,
+ *	| and tries to preload all the known packfiles in the ODB.
+ *  |
+ *	|-# packfile_load_all
+ *	  | Tries to find the `pack` folder, if it exists. ODBs without
+ *	  | a pack folder are ignored altogether. If there's a `pack` folder
+ *	  | we run a `dirent` callback through every file in the pack folder
+ *	  | to find our packfiles. The packfiles are then sorted according
+ *	  | to a sorting callback.
+ * 	  |
+ *	  |-# packfile_load__cb
+ *	  | | This callback is called from `dirent` with every single file
+ *	  | | inside the pack folder. We find the packs by actually locating
+ *	  | | their index (ends in ".idx"). From that index, we verify that
+ *	  | | the corresponding packfile exists and is valid, and if so, we
+ *    | | add it to the pack list.
+ *	  | |
+ *	  | |-# packfile_check
+ *	  |     Make sure that there's a packfile to back this index, and store
+ *	  |     some very basic information regarding the packfile itself,
+ *	  |     such as the full path, the size, and the modification time.
+ *	  |     We don't actually open the packfile to check for internal consistency.
+ *    |
+ *    |-# packfile_sort__cb
+ *        Sort all the preloaded packs according to some specific criteria:
+ *        we prioritize the "newer" packs because it's more likely they
+ *        contain the objects we are looking for, and we prioritize local
+ *        packs over remote ones.
+ *
+ *
+ *
+ *	Chapter 2: To be, or not to be...
+ *	A standard packed `exist` query for an OID
+ *	--------------------------------------------------
+ *
+ *  # pack_backend__exists
+ *  | Check if the given SHA1 oid exists in any of the packs
+ *  | that have been loaded for our ODB.
+ *  |
+ *  |-# pack_entry_find
+ *    | Iterate through all the packs that have been preloaded
+ *    | (starting by the pack where the latest object was found)
+ *    | to try to find the OID in one of them.
+ *    |
+ *    |-# pack_entry_find1
+ *      | Check the index of an individual pack to see if the SHA1
+ *      | OID can be found. If we can find the offset to that SHA1
+ *      | inside of the index, that means the object is contained
+ *      | inside of the packfile and we can stop searching.
+ *      | Before returning, we verify that the packfile behing the
+ *      | index we are searching still exists on disk.
+ *      |
+ *      |-# pack_entry_find_offset
+ *      | | Mmap the actual index file to disk if it hasn't been opened
+ *      | | yet, and run a binary search through it to find the OID.
+ *      | | See <http://book.git-scm.com/7_the_packfile.html> for specifics
+ *      | | on the Packfile Index format and how do we find entries in it.
+ *      | |
+ *      | |-# pack_index_open
+ *      |   | Guess the name of the index based on the full path to the
+ *      |   | packfile, open it and verify its contents. Only if the index
+ *      |   | has not been opened already.
+ *      |   |
+ *      |   |-# pack_index_check
+ *      |       Mmap the index file and do a quick run through the header
+ *      |       to guess the index version (right now we support v1 and v2),
+ *      |       and to verify that the size of the index makes sense.
+ *      |
+ *      |-# packfile_open
+ *          See `packfile_open` in Chapter 3
+ *
+ *
+ *
+ *	Chapter 3: The neverending story...
+ *	A standard packed `lookup` query for an OID
+ *	--------------------------------------------------
+ *	TODO
+ *
+ */
 
 
 
+ 
 /***********************************************************
  *
- * PACKFILE FUNCTIONS
- *
- * Locate, open and access the contents of a packfile
+ * FORWARD DECLARATIONS
  *
  ***********************************************************/
 
-static int pack_stat(git_pack *p)
-{
-	char pb[GIT_PATH_MAX];
-	struct stat sb;
+static void pack_window_free_all(struct pack_backend *backend, struct pack_file *p);
+static int pack_window_contains(struct pack_window *win, off_t offset);
 
-	if (git__fmt(pb, sizeof(pb), "%s/pack/%s.pack",
-			p->backend->objects_dir,
-			p->pack_name) < 0)
-		return GIT_ERROR;
+static void pack_window_scan_lru(struct pack_file *p, struct pack_file **lru_p,
+		struct pack_window **lru_w, struct pack_window **lru_l);
 
-	if (gitfo_stat(pb, &sb) || !S_ISREG(sb.st_mode))
-		return GIT_ERROR;
+static int pack_window_close_lru( struct pack_backend *backend,
+		struct pack_file *current, git_file keep_fd);
 
-	if (sb.st_size < (3 * 4 + GIT_OID_RAWSZ))
-		return GIT_ERROR;
+static void pack_window_close(struct pack_window **w_cursor);
 
-	p->pack_size = sb.st_size;
-	p->pack_mtime = sb.st_mtime;
+static unsigned char *pack_window_open( struct pack_backend *backend,
+		struct pack_file *p, struct pack_window **w_cursor, off_t offset,
+		unsigned int *left);
 
-	return GIT_SUCCESS;
-}
+static int packfile_sort__cb(const void *a_, const void *b_);
 
-static int pack_openidx(git_pack *p)
-{
-	gitlck_lock(&p->lock);
+static void pack_index_free(struct pack_file *p);
 
-	if (p->invalid) {
-		gitlck_unlock(&p->lock);
-		return GIT_ERROR;
-	}
+static int pack_index_check(const char *path,  struct pack_file *p);
+static int pack_index_open(struct pack_file *p);
 
-	if (++p->idxcnt == 1 && !p->idx_search) {
-		int status, version;
-		uint32_t *data;
+static struct pack_file *packfile_alloc(int extra);
+static int packfile_open(struct pack_file *p);
+static int packfile_check(struct pack_file **pack_out, const char *path, int local);
+static int packfile_load__cb(void *_data, char *path);
+static int packfile_load_all(struct pack_backend *backend, const char *odb_path, int local);
 
-		if (pack_stat(p) || pack_openidx_map(p)) {
-			p->invalid = 1;
-			p->idxcnt--;
-			gitlck_unlock(&p->lock);
-			return GIT_ERROR;
-		}
-		data = p->idx_map.data;
-		status = GIT_SUCCESS;
-		version = 1;
+static off_t nth_packed_object_offset(const struct pack_file *p, uint32_t n);
 
-		if (decode32(&data[0]) == PACK_TOC)
-			version = decode32(&data[1]);
-
-		switch (version) {
-		case 1:
-			status = pack_openidx_v1(p);
-			break;
-		case 2:
-			status = pack_openidx_v2(p);
-			break;
-		default:
-			status = GIT_ERROR;
-		}
+static int pack_entry_find_offset(off_t *offset_out,
+		struct pack_file *p, const git_oid *oid);
 
-		if (status != GIT_SUCCESS) {
-			gitfo_free_map(&p->idx_map);
-			p->invalid = 1;
-			p->idxcnt--;
-			gitlck_unlock(&p->lock);
-			return status;
-		}
-	}
+static int pack_entry_find1(struct pack_entry *e,
+		struct pack_file *p, const git_oid *oid);
 
-	gitlck_unlock(&p->lock);
-	return GIT_SUCCESS;
-}
+static int pack_entry_find(struct pack_entry *e,
+		struct pack_backend *backend, const git_oid *oid);
 
-static void pack_decidx(git_pack *p)
-{
-	gitlck_lock(&p->lock);
-	p->idxcnt--;
-	gitlck_unlock(&p->lock);
-}
+static off_t get_delta_base(struct pack_backend *backend,
+		struct pack_file *p, struct pack_window **w_curs,
+		off_t *curpos, git_otype type,
+		off_t delta_obj_offset);
 
-static int read_pack_hdr(pack_hdr *out, git_file fd)
-{
-	pack_hdr hdr;
+static unsigned long packfile_unpack_header1(
+		size_t *sizep,
+		git_otype *type, 
+		const unsigned char *buf,
+		unsigned long len);
 
-	if (gitfo_read(fd, &hdr, sizeof(hdr)))
-		return GIT_ERROR;
+static int packfile_unpack_header(
+		size_t *size_p,
+		git_otype *type_p,
+		struct pack_backend *backend,
+		struct pack_file *p,
+		struct pack_window **w_curs,
+		off_t *curpos);
 
-	out->sig = decode32(&hdr.sig);
-	out->ver = decode32(&hdr.ver);
-	out->cnt = decode32(&hdr.cnt);
+static int packfile_unpack_compressed(
+		git_rawobj *obj,
+		struct pack_backend *backend,
+		struct pack_file *p,
+		struct pack_window **w_curs,
+		off_t curpos,
+		size_t size,
+		git_otype type);
 
-	return GIT_SUCCESS;
-}
+static int packfile_unpack_delta(
+		git_rawobj *obj,
+		struct pack_backend *backend,
+		struct pack_file *p,
+		struct pack_window **w_curs,
+		off_t curpos,
+		size_t delta_size,
+		git_otype delta_type,
+		off_t obj_offset);
+
+static int packfile_unpack(git_rawobj *obj, struct pack_backend *backend,
+		struct pack_file *p, off_t obj_offset);
+
+
+
+
+
+/***********************************************************
+ *
+ * PACK WINDOW MANAGEMENT
+ *
+ ***********************************************************/
 
-static int check_pack_hdr(git_pack *p)
+void pack_window_free_all(struct pack_backend *backend, struct pack_file *p)
 {
-	pack_hdr hdr;
+	while (p->windows) {
+		struct pack_window *w = p->windows;
+		assert(w->inuse_cnt == 0);
 
-	if (read_pack_hdr(&hdr, p->pack_fd))
-		return GIT_ERROR;
+		backend->mapped -= w->window_map.len;
+		backend->open_windows--;
 
-	if (hdr.sig != PACK_SIG
-		|| (hdr.ver != 2 && hdr.ver != 3)
-		|| hdr.cnt != p->obj_cnt)
-		return GIT_ERROR;
+		gitfo_free_map(&w->window_map);
 
-	return GIT_SUCCESS;
+		p->windows = w->next;
+		free(w);
+	}
 }
 
-static int check_pack_sha1(git_pack *p)
+GIT_INLINE(int) pack_window_contains(struct pack_window *win, off_t offset)
 {
-	unsigned char *data = p->idx_map.data;
-	git_off_t pack_sha1_off = p->pack_size - GIT_OID_RAWSZ;
-	size_t idx_pack_sha1_off = p->idx_map.len - 2 * GIT_OID_RAWSZ;
-	git_oid pack_id, idx_pack_id;
+	/* We must promise at least 20 bytes (one hash) after the
+	 * offset is available from this window, otherwise the offset
+	 * is not actually in this window and a different window (which
+	 * has that one hash excess) must be used.  This is to support
+	 * the object header and delta base parsing routines below.
+	 */
+	off_t win_off = win->offset;
+	return win_off <= offset
+		&& (offset + 20) <= (off_t)(win_off + win->window_map.len);
+}
 
-	if (gitfo_lseek(p->pack_fd, pack_sha1_off, SEEK_SET) == -1)
-		return GIT_ERROR;
+static void pack_window_scan_lru(
+	struct pack_file *p,
+	struct pack_file **lru_p,
+	struct pack_window **lru_w,
+	struct pack_window **lru_l)
+{
+	struct pack_window *w, *w_l;
+
+	for (w_l = NULL, w = p->windows; w; w = w->next) {
+		if (!w->inuse_cnt) {
+			if (!*lru_w || w->last_used < (*lru_w)->last_used) {
+				*lru_p = p;
+				*lru_w = w;
+				*lru_l = w_l;
+			}
+		}
+		w_l = w;
+	}
+}
 
-	if (gitfo_read(p->pack_fd, pack_id.id, sizeof(pack_id.id)))
-		return GIT_ERROR;
+static int pack_window_close_lru(
+		struct pack_backend *backend,
+		struct pack_file *current,
+		git_file keep_fd)
+{
+	struct pack_file *lru_p = NULL;
+	struct pack_window *lru_w = NULL, *lru_l = NULL;
+	size_t i;
+
+	if (current)
+		pack_window_scan_lru(current, &lru_p, &lru_w, &lru_l);
+
+	for (i = 0; i < backend->packs.length; ++i)
+		pack_window_scan_lru(git_vector_get(&backend->packs, i), &lru_p, &lru_w, &lru_l);
+
+	if (lru_p) {
+		backend->mapped -= lru_w->window_map.len;
+		gitfo_free_map(&lru_w->window_map);
+
+		if (lru_l)
+			lru_l->next = lru_w->next;
+		else {
+			lru_p->windows = lru_w->next;
+			if (!lru_p->windows && lru_p->pack_fd != keep_fd) {
+				gitfo_close(lru_p->pack_fd);
+				lru_p->pack_fd = -1;
+			}
+		}
 
-	git_oid_mkraw(&idx_pack_id, data + idx_pack_sha1_off);
+		free(lru_w);
+		backend->open_windows--;
+		return GIT_SUCCESS;
+	}
 
-	if (git_oid_cmp(&pack_id, &idx_pack_id))
-		return GIT_ERROR;
+	return GIT_ERROR;
+}
 
-	return GIT_SUCCESS;
+static void pack_window_close(struct pack_window **w_cursor)
+{
+	struct pack_window *w = *w_cursor;
+	if (w) {
+		w->inuse_cnt--;
+		*w_cursor = NULL;
+	}
 }
 
-static int open_pack(git_pack *p)
+static unsigned char *pack_window_open(
+		struct pack_backend *backend,
+		struct pack_file *p,
+		struct pack_window **w_cursor,
+		off_t offset,
+		unsigned int *left)
 {
-	char pb[GIT_PATH_MAX];
-	struct stat sb;
+	struct pack_window *win = *w_cursor;
 
-	if (p->pack_fd != -1)
-		return GIT_SUCCESS;
+	if (p->pack_fd == -1 && packfile_open(p) < GIT_SUCCESS)
+		return NULL;
 
-	if (git__fmt(pb, sizeof(pb), "%s/pack/%s.pack",
-			p->backend->objects_dir,
-			p->pack_name) < 0)
-		return GIT_ERROR;
+	/* Since packfiles end in a hash of their content and it's
+	 * pointless to ask for an offset into the middle of that
+	 * hash, and the pack_window_contains function above wouldn't match
+	 * don't allow an offset too close to the end of the file.
+	 */
+	if (offset > (p->pack_size - 20))
+		return NULL;
 
-	if (pack_openidx(p))
-		return GIT_ERROR;
+	if (!win || !pack_window_contains(win, offset)) {
 
-	if ((p->pack_fd = gitfo_open(pb, O_RDONLY)) < 0)
-		goto error_cleanup;
+		if (win)
+			win->inuse_cnt--;
 
-	if (gitfo_fstat(p->pack_fd, &sb)
-		|| !S_ISREG(sb.st_mode) || p->pack_size != sb.st_size
-		|| check_pack_hdr(p) || check_pack_sha1(p))
-		goto error_cleanup;
+		for (win = p->windows; win; win = win->next) {
+			if (pack_window_contains(win, offset))
+				break;
+		}
 
-	if (!git__is_sizet(p->pack_size) ||
-		gitfo_map_ro(&p->pack_map, p->pack_fd, 0, (size_t)p->pack_size) < 0)
-		goto error_cleanup;
+		if (!win) {
+			size_t window_align = backend->window_size / 2;
+			size_t len;
 
-	pack_decidx(p);
-	return GIT_SUCCESS;
+			win = git__calloc(1, sizeof(*win));
+			win->offset = (offset / window_align) * window_align;
 
-error_cleanup:
-	gitfo_close(p->pack_fd);
-	p->pack_fd = -1;
-	pack_decidx(p);
-	return GIT_ERROR;
-}
+			len = (size_t)(p->pack_size - win->offset);
+			if (len > backend->window_size)
+				len = backend->window_size;
 
-static void pack_dec(git_pack *p)
-{
-	int need_free;
-
-	gitlck_lock(&p->lock);
-	need_free = !--p->refcnt;
-	gitlck_unlock(&p->lock);
-
-	if (need_free) {
-		if (p->idx_search) {
-			gitfo_free_map(&p->idx_map);
-			gitfo_close(p->idx_fd);
-			free(p->im_fanout);
-			free(p->im_off_idx);
-			free(p->im_off_next);
-			if (p->pack_fd != -1) {
-				gitfo_close(p->pack_fd);
-				gitfo_free_map(&p->pack_map);
-			}
+			backend->mapped += len;
+
+			while (backend->mapped_limit < backend->mapped &&
+				pack_window_close_lru(backend, p, p->pack_fd) == GIT_SUCCESS) {}
+
+			if (gitfo_map_ro(&win->window_map, p->pack_fd,
+					win->offset, len) < GIT_SUCCESS)
+				return NULL;
+
+			backend->mmap_calls++;
+			backend->open_windows++;
+
+			if (backend->mapped > backend->peak_mapped)
+				backend->peak_mapped = backend->mapped;
+
+			if (backend->open_windows > backend->peak_open_windows)
+				backend->peak_open_windows = backend->open_windows;
+
+			win->next = p->windows;
+			p->windows = win;
 		}
+	}
 
-		gitlck_free(&p->lock);
-		free(p);
+	if (win != *w_cursor) {
+		win->last_used = backend->used_ctr++;
+		win->inuse_cnt++;
+		*w_cursor = win;
 	}
+
+	offset -= win->offset;
+	assert(git__is_sizet(offset));
+
+	if (left)
+		*left = win->window_map.len - (size_t)offset;
+
+	return (unsigned char *)win->window_map.data + offset;
 }
 
-static void packlist_dec(pack_backend *backend, git_packlist *pl)
-{
-	int need_free;
 
-	assert(backend && pl);
 
-	gitlck_lock(&backend->lock);
-	need_free = !--pl->refcnt;
-	gitlck_unlock(&backend->lock);
 
-	if (need_free) {
-		size_t j;
-		for (j = 0; j < pl->n_packs; j++)
-			pack_dec(pl->packs[j]);
-		free(pl);
+
+
+
+/***********************************************************
+ *
+ * PACK INDEX METHODS
+ *
+ ***********************************************************/
+
+static void pack_index_free(struct pack_file *p)
+{
+	if (p->index_map.data) {
+		gitfo_free_map(&p->index_map);
+		p->index_map.data = NULL;
 	}
 }
 
-static git_pack *alloc_pack(const char *pack_name)
+static int pack_index_check(const char *path,  struct pack_file *p)
 {
-	git_pack *p = git__calloc(1, sizeof(*p));
-	if (!p)
-		return NULL;
+	struct pack_idx_header *hdr;
+	uint32_t version, nr, i, *index;
 
-	gitlck_init(&p->lock);
-	strcpy(p->pack_name, pack_name);
-	p->refcnt = 1;
-	p->pack_fd = -1;
-	return p;
-}
+	void *idx_map;
+	size_t idx_size;
 
-struct scanned_pack {
-	struct scanned_pack *next;
-	git_pack *pack;
-};
+	struct stat st;
 
-static int scan_one_pack(void *state, char *name)
-{
-	struct scanned_pack **ret = state, *r;
-	char *s = strrchr(name, '/'), *d;
+	/* TODO: properly open the file without access time */
+	git_file fd = gitfo_open(path, O_RDONLY /*| O_NOATIME */);
 
-	if (git__prefixcmp(s + 1, "pack-")
-	 || git__suffixcmp(s, ".pack")
-	 || strlen(s + 1) != GIT_PACK_NAME_MAX + 4)
-		return 0;
-
-	d = strrchr(s + 1, '.');
-	strcpy(d + 1, "idx");    /* "pack-abc.pack" -> "pack-abc.idx" */
-	if (gitfo_exists(name))
-		return 0;
+	int error;
 
-	if ((r = git__malloc(sizeof(*r))) == NULL)
-		return GIT_ERROR;
+	if (fd < 0)
+		return GIT_EOSERR;
 
-	*d = '\0';               /* "pack-abc.pack" -_> "pack-abc" */
-	if ((r->pack = alloc_pack(s + 1)) == NULL) {
-		free(r);
-		return GIT_ERROR;
+	if (gitfo_fstat(fd, &st) < GIT_SUCCESS) {
+		gitfo_close(fd);
+		return GIT_EOSERR;
 	}
 
-	r->next = *ret;
-	*ret = r;
-	return 0;
-}
+	if (!git__is_sizet(st.st_size))
+		return GIT_ENOMEM;
 
-static git_packlist *scan_packs(pack_backend *backend)
-{
-	char pb[GIT_PATH_MAX];
-	struct scanned_pack *state = NULL, *c;
-	size_t cnt;
-	git_packlist *new_list;
+	idx_size = (size_t)st.st_size;
 
-	if (git__fmt(pb, sizeof(pb), "%s/pack", backend->objects_dir) < 0)
-		return NULL;
-	gitfo_dirent(pb, sizeof(pb), scan_one_pack, &state);
-
-	/* TODO - merge old entries into the new array */
-	for (cnt = 0, c = state; c; c = c->next)
-		cnt++;
-	new_list = git__malloc(sizeof(*new_list)
-		+ (sizeof(new_list->packs[0]) * cnt));
-	if (!new_list)
-		goto fail;
-
-	for (cnt = 0, c = state; c; ) {
-		struct scanned_pack *n = c->next;
-		c->pack->backend = backend;
-		new_list->packs[cnt++] = c->pack;
-		free(c);
-		c = n;
-	}
-	new_list->n_packs = cnt;
-	new_list->refcnt = 2;
-	backend->packlist = new_list;
-	return new_list;
-
-fail:
-	while (state) {
-		struct scanned_pack *n = state->next;
-		pack_dec(state->pack);
-		free(state);
-		state = n;
+	if (idx_size < 4 * 256 + 20 + 20) {
+		gitfo_close(fd);
+		return GIT_EOBJCORRUPTED;
 	}
-	return NULL;
-}
 
-static git_packlist *packlist_get(pack_backend *backend)
-{
-	git_packlist *pl;
-
-	gitlck_lock(&backend->lock);
-	if ((pl = backend->packlist) != NULL)
-		pl->refcnt++;
-	else
-		pl = scan_packs(backend);
-	gitlck_unlock(&backend->lock);
-	return pl;
-}
+	error = gitfo_map_ro(&p->index_map, fd, 0, idx_size);
+	gitfo_close(fd);
 
-static int locate_packfile(pack_location *location, pack_backend *backend, const git_oid *id)
-{
-	git_packlist *pl = packlist_get(backend);
-	size_t j;
+	if (error < GIT_SUCCESS)
+		return error;
 
-	if (!pl)
-		return GIT_ENOTFOUND;
+	hdr = idx_map = p->index_map.data;
 
-	for (j = 0; j < pl->n_packs; j++) {
+	if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
+		version = ntohl(hdr->idx_version);
 
-		git_pack *pack = pl->packs[j];
-		uint32_t pos;
-		int res;
+		if (version < 2 || version > 2) {
+			gitfo_free_map(&p->index_map);
+			return GIT_EOBJCORRUPTED; /* unsupported index version */
+		}
 
-		if (pack_openidx(pack))
-			continue;
+	} else
+		version = 1;
 
-		res = pack->idx_search(&pos, pack, id);
-		pack_decidx(pack);
+	nr = 0;
+	index = idx_map;
 
-		if (!res) {
-			packlist_dec(backend, pl);
+	if (version > 1)
+		index += 2;  /* skip index header */
 
-			location->ptr = pack;
-			location->n = pos;
+	for (i = 0; i < 256; i++) {
+		uint32_t n = ntohl(index[i]);
+		if (n < nr) {
+			gitfo_free_map(&p->index_map);
+			return GIT_EOBJCORRUPTED; /* non-monotonic index */
+		}
+		nr = n;
+	}
 
-			return GIT_SUCCESS;
+	if (version == 1) {
+		/*
+		 * Total size:
+		 *  - 256 index entries 4 bytes each
+		 *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
+		 *  - 20-byte SHA1 of the packfile
+		 *  - 20-byte SHA1 file checksum
+		 */
+		if (idx_size != 4*256 + nr * 24 + 20 + 20) {
+			gitfo_free_map(&p->index_map);
+			return GIT_EOBJCORRUPTED;
+		}
+	} else if (version == 2) {
+		/*
+		 * Minimum size:
+		 *  - 8 bytes of header
+		 *  - 256 index entries 4 bytes each
+		 *  - 20-byte sha1 entry * nr
+		 *  - 4-byte crc entry * nr
+		 *  - 4-byte offset entry * nr
+		 *  - 20-byte SHA1 of the packfile
+		 *  - 20-byte SHA1 file checksum
+		 * And after the 4-byte offset table might be a
+		 * variable sized table containing 8-byte entries
+		 * for offsets larger than 2^31.
+		 */
+		unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
+		unsigned long max_size = min_size;
+
+		if (nr)
+			max_size += (nr - 1)*8;
+
+		if (idx_size < min_size || idx_size > max_size) {
+			gitfo_free_map(&p->index_map);
+			return GIT_EOBJCORRUPTED;
 		}
 
+		/* Make sure that off_t is big enough to access the whole pack...
+		 * Is this an issue in libgit2? It shouldn't. */
+		if (idx_size != min_size && (sizeof(off_t) <= 4)) {
+			gitfo_free_map(&p->index_map);
+			return GIT_EOSERR;
+		}
 	}
 
-	packlist_dec(backend, pl);
-	return GIT_ENOTFOUND;
+	p->index_version = version;
+	p->num_objects = nr;
+	return GIT_SUCCESS;
 }
 
+static int pack_index_open(struct pack_file *p)
+{
+	char *idx_name;
+	int error;
+
+	if (p->index_map.data)
+		return GIT_SUCCESS;
 
+	idx_name = git__strdup(p->pack_name);
+	strcpy(idx_name + strlen(idx_name) - STRLEN(".pack"), ".idx");
 
+	error = pack_index_check(idx_name, p);
+	free(idx_name);
 
+	return error;
+}
 
 
 
@@ -541,350 +663,225 @@ static int locate_packfile(pack_location *location, pack_backend *backend, const
 
 /***********************************************************
  *
- * PACKFILE INDEX FUNCTIONS
- *
- * Get index formation for packfile indexes v1 and v2
+ * PACKFILE METHODS
  *
  ***********************************************************/
 
-static int pack_openidx_map(git_pack *p)
+static int packfile_sort__cb(const void *a_, const void *b_)
 {
-	char pb[GIT_PATH_MAX];
-	git_off_t len;
-
-	if (git__fmt(pb, sizeof(pb), "%s/pack/%s.idx",
-			p->backend->objects_dir,
-			p->pack_name) < 0)
-		return GIT_ERROR;
-
-	if ((p->idx_fd = gitfo_open(pb, O_RDONLY)) < 0)
-		return GIT_ERROR;
-
-	if ((len = gitfo_size(p->idx_fd)) < 0
-		|| !git__is_sizet(len)
-		|| gitfo_map_ro(&p->idx_map, p->idx_fd, 0, (size_t)len)) {
-		gitfo_close(p->idx_fd);
-		return GIT_ERROR;
-	}
+	struct pack_file *a = *((struct pack_file **)a_);
+	struct pack_file *b = *((struct pack_file **)b_);
+	int st;
 
-	return GIT_SUCCESS;
+	/*
+	 * Local packs tend to contain objects specific to our
+	 * variant of the project than remote ones.  In addition,
+	 * remote ones could be on a network mounted filesystem.
+	 * Favor local ones for these reasons.
+	 */
+	st = a->pack_local - b->pack_local;
+	if (st)
+		return -st;
+
+	/*
+	 * Younger packs tend to contain more recent objects,
+	 * and more recent objects tend to get accessed more
+	 * often.
+	 */
+	if (a->mtime < b->mtime)
+		return 1;
+	else if (a->mtime == b->mtime)
+		return 0;
+
+	return -1;
 }
 
-typedef struct {
-	git_off_t offset;
-	uint32_t n;
-} offset_idx_info;
+static struct pack_file *packfile_alloc(int extra)
+{
+	struct pack_file *p = git__malloc(sizeof(*p) + extra);
+	memset(p, 0, sizeof(*p));
+	p->pack_fd = -1;
+	return p;
+}
 
-static int cmp_offset_idx_info(const void *lhs, const void *rhs)
+
+static void packfile_free(struct pack_backend *backend, struct pack_file *p)
 {
-	const offset_idx_info *a = lhs;
-	const offset_idx_info *b = rhs;
-	return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
+	assert(p);
+
+	/* clear_delta_base_cache(); */
+	pack_window_free_all(backend, p);
+
+	if (p->pack_fd != -1)
+		gitfo_close(p->pack_fd);
+
+	pack_index_free(p);
+
+	free(p->bad_object_sha1);
+	free(p);
 }
 
-static int make_offset_index(git_pack *p, offset_idx_info *data)
+static int packfile_open(struct pack_file *p)
 {
-	git_off_t min_off = 3 * 4, max_off = p->pack_size - GIT_OID_RAWSZ;
-	uint32_t *idx, *next;
-	uint32_t j;
+	struct stat st;
+	struct pack_header hdr;
+	git_oid sha1;
+	unsigned char *idx_sha1;
 
-	qsort(data, p->obj_cnt, sizeof(*data), cmp_offset_idx_info);
+	if (!p->index_map.data && pack_index_open(p) < GIT_SUCCESS)
+		return GIT_ENOTFOUND;
 
-	if (data[0].offset < min_off || data[p->obj_cnt].offset > max_off)
-		return GIT_ERROR;
+	/* TODO: open with noatime */
+	p->pack_fd = gitfo_open(p->pack_name, O_RDONLY);
+	if (p->pack_fd < 0 || gitfo_fstat(p->pack_fd, &st) < GIT_SUCCESS)
+		return GIT_EOSERR;
+
+	/* If we created the struct before we had the pack we lack size. */
+	if (!p->pack_size) {
+		if (!S_ISREG(st.st_mode))
+			goto cleanup;
+		p->pack_size = (off_t)st.st_size;
+	} else if (p->pack_size != st.st_size)
+		goto cleanup;
 
-	if ((idx = git__malloc(sizeof(*idx) * (p->obj_cnt+1))) == NULL)
-		return GIT_ERROR;
-	if ((next = git__malloc(sizeof(*next) * p->obj_cnt)) == NULL) {
-		free(idx);
-		return GIT_ERROR;
-	}
+#if 0
+	/* We leave these file descriptors open with sliding mmap;
+	 * there is no point keeping them open across exec(), though.
+	 */
+	fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
+	if (fd_flag < 0)
+		return error("cannot determine file descriptor flags");
 
-	for (j = 0; j < p->obj_cnt+1; j++)
-		idx[j] = data[j].n;
+	fd_flag |= FD_CLOEXEC;
+	if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
+		return GIT_EOSERR;
+#endif
 
-	for (j = 0; j < p->obj_cnt; j++) {
-		assert(idx[j]   < p->obj_cnt);
-		assert(idx[j+1] < p->obj_cnt+1);
+	/* Verify we recognize this pack file format. */
+	if (gitfo_read(p->pack_fd, &hdr, sizeof(hdr)) < GIT_SUCCESS)
+		goto cleanup;
 
-		next[idx[j]] = idx[j+1];
-	}
+	if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
+		goto cleanup;
 
-	p->im_off_idx = idx;
-	p->im_off_next = next;
-	return GIT_SUCCESS;
-}
+	if (!pack_version_ok(hdr.hdr_version))
+		goto cleanup;
 
-static int idxv1_search(uint32_t *out, git_pack *p, const git_oid *id)
-{
-	unsigned char *data = p->im_oid;
-	uint32_t lo = id->id[0] ? p->im_fanout[id->id[0] - 1] : 0;
-	uint32_t hi = p->im_fanout[id->id[0]];
+	/* Verify the pack matches its index. */
+	if (p->num_objects != ntohl(hdr.hdr_entries))
+		goto cleanup;
 
-	do {
-		uint32_t mid = (lo + hi) >> 1;
-		uint32_t pos = 24 * mid;
-		int cmp = memcmp(id->id, data + pos + 4, 20);
-		if (cmp < 0)
-			hi = mid;
-		else if (!cmp) {
-			*out = mid;
-			return GIT_SUCCESS;
-		} else
-			lo = mid + 1;
-	} while (lo < hi);
-	return GIT_ENOTFOUND;
-}
+	if (gitfo_lseek(p->pack_fd, p->pack_size - GIT_OID_RAWSZ, SEEK_SET) == -1)
+		goto cleanup;
 
-static int idxv1_search_offset(uint32_t *out, git_pack *p, git_off_t offset)
-{
-	if (offset > 0 && offset < (p->pack_size - GIT_OID_RAWSZ)) {
-		uint32_t lo = 0, hi = p->obj_cnt+1;
-		unsigned char *data = p->im_oid;
-		uint32_t *idx = p->im_off_idx;
-		do {
-			uint32_t mid = (lo + hi) >> 1;
-			uint32_t n = idx[mid];
-			uint32_t pos = n * (GIT_OID_RAWSZ + 4);
-			git_off_t here = decode32(data + pos);
-			if (offset < here)
-				hi = mid;
-			else if (offset == here) {
-				*out = n;
-				return GIT_SUCCESS;
-			} else
-				lo = mid + 1;
-		} while (lo < hi);
-	}
-	return GIT_ENOTFOUND;
-}
+	if (gitfo_read(p->pack_fd, sha1.id, GIT_OID_RAWSZ) < GIT_SUCCESS)
+		goto cleanup;
 
-static int idxv1_get(index_entry *e, git_pack *p, uint32_t n)
-{
-	unsigned char *data = p->im_oid;
-	uint32_t *next = p->im_off_next;
-
-	if (n < p->obj_cnt) {
-		uint32_t pos = n * (GIT_OID_RAWSZ + 4);
-		git_off_t next_off = p->pack_size - GIT_OID_RAWSZ;
-		e->n = n;
-		e->oid = data + pos + 4;
-		e->offset = decode32(data + pos);
-		if (next[n] < p->obj_cnt) {
-			pos = next[n] * (GIT_OID_RAWSZ + 4);
-			next_off = decode32(data + pos);
-		}
-		e->size = next_off - e->offset;
-		return GIT_SUCCESS;
-	}
-	return GIT_ENOTFOUND;
+	idx_sha1 = ((unsigned char *)p->index_map.data) + p->index_map.len - 40;
+
+	if (git_oid_cmp(&sha1, (git_oid *)idx_sha1) != 0)
+		goto cleanup;
+
+	return GIT_SUCCESS;	
+
+cleanup:
+	gitfo_close(p->pack_fd);
+	p->pack_fd = -1;
+	return GIT_EPACKCORRUPTED;
 }
 
-static int pack_openidx_v1(git_pack *p)
+static int packfile_check(struct pack_file **pack_out, const char *path, int local)
 {
-	uint32_t *src_fanout = p->idx_map.data;
-	uint32_t *im_fanout;
-	offset_idx_info *info;
-	size_t expsz;
-	uint32_t j;
-
-
-	if ((im_fanout = git__malloc(sizeof(*im_fanout) * 256)) == NULL)
-		return GIT_ERROR;
-
-	im_fanout[0] = decode32(&src_fanout[0]);
-	for (j = 1; j < 256; j++) {
-		im_fanout[j] = decode32(&src_fanout[j]);
-		if (im_fanout[j] < im_fanout[j - 1]) {
-			free(im_fanout);
-			return GIT_ERROR;
-		}
-	}
-	p->obj_cnt = im_fanout[255];
+	struct stat st;
+	struct pack_file *p;
+	size_t path_len;
+
+	*pack_out = NULL;
+	path_len = strlen(path);
+	p = packfile_alloc(path_len + 2);
 
-	expsz = 4 * 256 + 24 * p->obj_cnt + 2 * 20;
-	if (expsz != p->idx_map.len) {
-		free(im_fanout);
-		return GIT_ERROR;
+	/*
+	 * Make sure a corresponding .pack file exists and that
+	 * the index looks sane.
+	 */
+	path_len -= STRLEN(".idx");
+	if (path_len < 1) {
+		free(p);
+		return GIT_ENOTFOUND;
 	}
 
-	p->idx_search = idxv1_search;
-	p->idx_search_offset = idxv1_search_offset;
-	p->idx_get = idxv1_get;
-	p->im_fanout = im_fanout;
-	p->im_oid = (unsigned char *)(src_fanout + 256);
+	memcpy(p->pack_name, path, path_len);
 
-	if ((info = git__malloc(sizeof(*info) * (p->obj_cnt+1))) == NULL) {
-		free(im_fanout);
-		return GIT_ERROR;
-	}
+	strcpy(p->pack_name + path_len, ".keep");
+	if (gitfo_exists(p->pack_name) == GIT_SUCCESS)
+		p->pack_keep = 1;
 
-	for (j = 0; j < p->obj_cnt; j++) {
-		uint32_t pos = j * (GIT_OID_RAWSZ + 4);
-		info[j].offset = decode32(p->im_oid + pos);
-		info[j].n = j;
+	strcpy(p->pack_name + path_len, ".pack");
+	if (gitfo_stat(p->pack_name, &st) < GIT_SUCCESS || !S_ISREG(st.st_mode)) {
+		free(p);
+		return GIT_ENOTFOUND;
 	}
-	info[p->obj_cnt].offset = p->pack_size - GIT_OID_RAWSZ;
-	info[p->obj_cnt].n = p->obj_cnt;
 
-	if (make_offset_index(p, info)) {
-		free(im_fanout);
-		free(info);
-		return GIT_ERROR;
-	}
-	free(info);
+	/* ok, it looks sane as far as we can check without
+	 * actually mapping the pack file.
+	 */
+	p->pack_size = (off_t)st.st_size;
+	p->pack_local = local;
+	p->mtime = (git_time_t)st.st_mtime;
 
+	/* see if we can parse the sha1 oid in the packfile name */
+	if (path_len < 40 ||
+		git_oid_mkstr(&p->sha1, path + path_len - GIT_OID_HEXSZ) < GIT_SUCCESS)
+		memset(&p->sha1, 0x0, GIT_OID_RAWSZ);
+
+	*pack_out = p;
 	return GIT_SUCCESS;
 }
 
-static int idxv2_search(uint32_t *out, git_pack *p, const git_oid *id)
+static int packfile_load__cb(void *_data, char *path)
 {
-	unsigned char *data = p->im_oid;
-	uint32_t lo = id->id[0] ? p->im_fanout[id->id[0] - 1] : 0;
-	uint32_t hi = p->im_fanout[id->id[0]];
+	struct pack__dirent *data = (struct pack__dirent *)_data;
+	struct pack_file *pack;
+	int error;
 
-	do {
-		uint32_t mid = (lo + hi) >> 1;
-		uint32_t pos = 20 * mid;
-		int cmp = memcmp(id->id, data + pos, 20);
-		if (cmp < 0)
-			hi = mid;
-		else if (!cmp) {
-			*out = mid;
-			return GIT_SUCCESS;
-		} else
-			lo = mid + 1;
-	} while (lo < hi);
-	return GIT_ENOTFOUND;
-}
+	if (git__suffixcmp(path, ".idx") != 0)
+		return GIT_SUCCESS; /* not an index */
 
-static int idxv2_search_offset(uint32_t *out, git_pack *p, git_off_t offset)
-{
-	if (offset > 0 && offset < (p->pack_size - GIT_OID_RAWSZ)) {
-		uint32_t lo = 0, hi = p->obj_cnt+1;
-		uint32_t *idx = p->im_off_idx;
-		do {
-			uint32_t mid = (lo + hi) >> 1;
-			uint32_t n = idx[mid];
-			uint32_t o32 = decode32(p->im_offset32 + n);
-			git_off_t here = o32;
-
-			if (o32 & 0x80000000) {
-				uint32_t o64_idx = (o32 & ~0x80000000);
-				here = decode64(p->im_offset64 + 2*o64_idx);
-			}
+	/* FIXME: git.git checks for duplicate packs.
+	 * But that makes no fucking sense. Our dirent is not
+	 * going to generate dupicate entries */
 
-			if (offset < here)
-				hi = mid;
-			else if (offset == here) {
-				*out = n;
-				return GIT_SUCCESS;
-			} else
-				lo = mid + 1;
-		} while (lo < hi);
-	}
-	return GIT_ENOTFOUND;
-}
+	error = packfile_check(&pack, path, data->is_pack_local);
+	if (error < GIT_SUCCESS)
+		return error;
 
-static int idxv2_get(index_entry *e, git_pack *p, uint32_t n)
-{
-	unsigned char *data = p->im_oid;
-	uint32_t *next = p->im_off_next;
-
-	if (n < p->obj_cnt) {
-		uint32_t o32 = decode32(p->im_offset32 + n);
-		git_off_t next_off = p->pack_size - GIT_OID_RAWSZ;
-		e->n = n;
-		e->oid = data + n * GIT_OID_RAWSZ;
-		e->offset = o32;
-		if (o32 & 0x80000000) {
-			uint32_t o64_idx = (o32 & ~0x80000000);
-			e->offset = decode64(p->im_offset64 + 2*o64_idx);
-		}
-		if (next[n] < p->obj_cnt) {
-			o32 = decode32(p->im_offset32 + next[n]);
-			next_off = o32;
-			if (o32 & 0x80000000) {
-				uint32_t o64_idx = (o32 & ~0x80000000);
-				next_off = decode64(p->im_offset64 + 2*o64_idx);
-			}
-		}
-		e->size = next_off - e->offset;
-		return GIT_SUCCESS;
+	if (git_vector_insert(&data->backend->packs, pack) < GIT_SUCCESS) {
+		free(pack);
+		return GIT_ENOMEM;
 	}
-	return GIT_ENOTFOUND;
+
+	return GIT_SUCCESS;
 }
 
-static int pack_openidx_v2(git_pack *p)
+static int packfile_load_all(struct pack_backend *backend, const char *odb_path, int local)
 {
-	unsigned char *data = p->idx_map.data;
-	uint32_t *src_fanout = (uint32_t *)(data + 8);
-	uint32_t *im_fanout;
-	offset_idx_info *info;
-	size_t sz, o64_sz, o64_len;
-	uint32_t j;
-
-	if ((im_fanout = git__malloc(sizeof(*im_fanout) * 256)) == NULL)
-		return GIT_ERROR;
-
-	im_fanout[0] = decode32(&src_fanout[0]);
-	for (j = 1; j < 256; j++) {
-		im_fanout[j] = decode32(&src_fanout[j]);
-		if (im_fanout[j] < im_fanout[j - 1]) {
-			free(im_fanout);
-			return GIT_ERROR;
-		}
-	}
-	p->obj_cnt = im_fanout[255];
+	int error;
+	char path[GIT_PATH_MAX];
+	struct pack__dirent data;
 
-	/* minimum size of .idx file (with empty 64-bit offsets table): */
-	sz = 4 + 4 + 256 * 4 + p->obj_cnt * (20 + 4 + 4) + 2 * 20;
-	if (p->idx_map.len < sz) {
-		free(im_fanout);
-		return GIT_ERROR;
-	}
+	data.backend = backend;
+	data.is_pack_local = local;
 
-	p->idx_search = idxv2_search;
-	p->idx_search_offset = idxv2_search_offset;
-	p->idx_get = idxv2_get;
-	p->im_fanout = im_fanout;
-	p->im_oid = (unsigned char *)(src_fanout + 256);
-	p->im_crc = (uint32_t *)(p->im_oid + 20 * p->obj_cnt);
-	p->im_offset32 = p->im_crc + p->obj_cnt;
-	p->im_offset64 = p->im_offset32 + p->obj_cnt;
-
-	if ((info = git__malloc(sizeof(*info) * (p->obj_cnt+1))) == NULL) {
-		free(im_fanout);
-		return GIT_ERROR;
-	}
+	git__joinpath(path, odb_path, "pack");
+	if (gitfo_isdir(path) < GIT_SUCCESS)
+		return GIT_SUCCESS;
 
-	/* check 64-bit offset table index values are within bounds */
-	o64_sz = p->idx_map.len - sz;
-	o64_len = o64_sz / 8;
-	for (j = 0; j < p->obj_cnt; j++) {
-		uint32_t o32 = decode32(p->im_offset32 + j);
-		git_off_t offset = o32;
-		if (o32 & 0x80000000) {
-			uint32_t o64_idx = (o32 & ~0x80000000);
-			if (o64_idx >= o64_len) {
-				free(im_fanout);
-				free(info);
-				return GIT_ERROR;
-			}
-			offset = decode64(p->im_offset64 + 2*o64_idx);
-		}
-		info[j].offset = offset;
-		info[j].n = j;
-	}
-	info[p->obj_cnt].offset = p->pack_size - GIT_OID_RAWSZ;
-	info[p->obj_cnt].n = p->obj_cnt;
+	error = gitfo_dirent(path, GIT_PATH_MAX, packfile_load__cb, (void *)&data);
+	if (error < GIT_SUCCESS)
+		return error;
 
-	if (make_offset_index(p, info)) {
-		free(im_fanout);
-		free(info);
-		return GIT_ERROR;
-	}
-	free(info);
+	git_vector_sort(&backend->packs);
+	backend->last_found = git_vector_get(&backend->packs, 0);
 
 	return GIT_SUCCESS;
 }
@@ -898,221 +895,421 @@ static int pack_openidx_v2(git_pack *p)
 
 /***********************************************************
  *
- * PACKFILE READING FUNCTIONS
- *
- * Read the contents of a packfile
+ * PACKFILE ENTRY SEARCH INTERNALS
  *
  ***********************************************************/
 
+static off_t nth_packed_object_offset(const struct pack_file *p, uint32_t n)
+{
+	const unsigned char *index = p->index_map.data;
+	index += 4 * 256;
+	if (p->index_version == 1) {
+		return ntohl(*((uint32_t *)(index + 24 * n)));
+	} else {
+		uint32_t off;
+		index += 8 + p->num_objects * (20 + 4);
+		off = ntohl(*((uint32_t *)(index + 4 * n)));
+		if (!(off & 0x80000000))
+			return off;
+		index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
+		return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
+				   ntohl(*((uint32_t *)(index + 4)));
+	}
+}
 
-static int unpack_object(git_rawobj *out, git_pack *p, index_entry *e);
-
-static int unpack_object_delta(git_rawobj *out, git_pack *p,
-		index_entry *base_entry,
-		uint8_t *delta_buffer,
-		size_t delta_deflated_size,
-		size_t delta_inflated_size)
+static int pack_entry_find_offset(
+		off_t *offset_out,
+		struct pack_file *p,
+		const git_oid *oid)
 {
-	int res = 0;
-	uint8_t *delta = NULL;
-	git_rawobj base_obj;
+	const uint32_t *level1_ofs = p->index_map.data;
+	const unsigned char *index = p->index_map.data;
+	unsigned hi, lo, stride;
 
-	base_obj.data = NULL;
-	base_obj.type = GIT_OBJ_BAD;
-	base_obj.len = 0;
+	*offset_out = 0;
 
-	if ((res = unpack_object(&base_obj, p, base_entry)) < 0)
-		goto cleanup;
+	if (index == NULL) {
+		int error;
 
-	delta = git__malloc(delta_inflated_size + 1);
+		if ((error = pack_index_open(p)) < GIT_SUCCESS)
+			return error;
 
-	if ((res = git_odb__inflate_buffer(delta_buffer, delta_deflated_size,
-			delta, delta_inflated_size)) < 0)
-		goto cleanup;
+		assert(p->index_map.data);
 
-	res = git__delta_apply(out, base_obj.data, base_obj.len, delta, delta_inflated_size);
+		index = p->index_map.data;
+		level1_ofs = p->index_map.data;
+	}
 
-	out->type = base_obj.type;
+	if (p->index_version > 1) {
+		level1_ofs += 2;
+		index += 8;
+	}
 
-cleanup:
-	free(delta);
-	git_rawobj_close(&base_obj);
-	return res;
-}
+	index += 4 * 256;
+	hi = ntohl(level1_ofs[(int)oid->id[0]]);
+	lo = ((oid->id[0] == 0x0) ? 0 : ntohl(level1_ofs[(int)oid->id[0] - 1]));
 
-static int unpack_object(git_rawobj *out, git_pack *p, index_entry *e)
-{
-	git_otype object_type;
-	size_t inflated_size, deflated_size, shift;
-	uint8_t *buffer, byte;
+	if (p->index_version > 1) {
+		stride = 20;
+	} else {
+		stride = 24;
+		index += 4;
+	}
 
-	assert(out && p && e && git__is_sizet(e->size));
+#ifdef INDEX_DEBUG_LOOKUP
+	printf("%02x%02x%02x... lo %u hi %u nr %d\n",
+		oid->id[0], oid->id[1], oid->id[2], lo, hi, p->num_objects);
+#endif
 
-	if (open_pack(p))
-		return GIT_ERROR;
+#ifdef GIT2_INDEX_LOOKUP /* TODO: use the advanced lookup method from git.git */
 
-	buffer = (uint8_t *)p->pack_map.data + e->offset;
-	deflated_size = (size_t)e->size;
+	int pos = sha1_entry_pos(index, stride, 0, lo, hi, p->num_objects, oid);
+	if (pos < 0)
+		return GIT_ENOTFOUND;
 
-	if (deflated_size == 0)
-		deflated_size = (size_t)(p->pack_size - e->offset);
+	*offset_out = nth_packed_object_offset(p, pos);
+	return GIT_SUCCESS;
 
-	byte = *buffer++ & 0xFF;
-	deflated_size--;
-	object_type = (byte >> 4) & 0x7;
-	inflated_size = byte & 0xF;
-	shift = 4;
+#else /* use an old and boring binary search */
 
-	while (byte & 0x80) {
-		byte = *buffer++ & 0xFF;
-		deflated_size--;
-		inflated_size += (byte & 0x7F) << shift;
-		shift += 7;
-	}
+	do {
+		unsigned mi = (lo + hi) / 2;
+		int cmp = memcmp(index + mi * stride, oid->id, GIT_OID_RAWSZ);
+
+		if (!cmp) {
+			*offset_out = nth_packed_object_offset(p, mi);
+			return GIT_SUCCESS;
+		}
 
-	switch (object_type) {
-		case GIT_OBJ_COMMIT:
-		case GIT_OBJ_TREE:
-		case GIT_OBJ_BLOB:
-		case GIT_OBJ_TAG: {
+		if (cmp > 0)
+			hi = mi;
+		else
+			lo = mi+1;
 
-			/* Handle a normal zlib stream */
-			out->len = inflated_size;
-			out->type = object_type;
-			out->data = git__malloc(inflated_size + 1);
+	} while (lo < hi);
+
+	return GIT_ENOTFOUND;
+#endif
+}
+
+static int pack_entry_find1(
+		struct pack_entry *e,
+		struct pack_file *p,
+		const git_oid *oid)
+{
+	off_t offset;
 
-			if (git_odb__inflate_buffer(buffer, deflated_size, out->data, out->len) < 0) {
-				free(out->data);
-				out->data = NULL;
+	assert(p);
+
+	if (p->num_bad_objects) {
+		unsigned i;
+		for (i = 0; i < p->num_bad_objects; i++)
+			if (git_oid_cmp(oid, &p->bad_object_sha1[i]) == 0)
 				return GIT_ERROR;
-			}
+	}
 
-			return GIT_SUCCESS;
-		}
+	if (pack_entry_find_offset(&offset, p, oid) < GIT_SUCCESS)
+		return GIT_ENOTFOUND;
+	
+	/* we found an entry in the index;
+	 * make sure the packfile backing the index 
+	 * still exists on disk */
+	if (p->pack_fd == -1 && packfile_open(p) < GIT_SUCCESS)
+		return GIT_EOSERR;
 
-		case GIT_OBJ_OFS_DELTA: {
+	e->offset = offset;
+	e->p = p;
 
-			git_off_t delta_offset;
-			index_entry entry;
+	git_oid_cpy(&e->sha1, oid);
+	return GIT_SUCCESS;
+}
 
-			byte = *buffer++ & 0xFF;
-			delta_offset = byte & 0x7F;
+static int pack_entry_find(struct pack_entry *e, struct pack_backend *backend, const git_oid *oid)
+{
+	size_t i;
 
-			while (byte & 0x80) {
-				delta_offset += 1;
-				byte = *buffer++ & 0xFF;
-				delta_offset <<= 7;
-				delta_offset += (byte & 0x7F);
-			}
+	if (backend->last_found &&
+		pack_entry_find1(e, backend->last_found, oid) == GIT_SUCCESS)
+		return GIT_SUCCESS;
 
-			entry.n = 0;
-			entry.oid = NULL;
-			entry.offset = e->offset - delta_offset;
-			entry.size = 0;
+	for (i = 0; i < backend->packs.length; ++i) {
+		struct pack_file *p;
 
-			if (unpack_object_delta(out, p, &entry,
-					buffer, deflated_size, inflated_size) < 0)
-				return GIT_ERROR;
+		p = git_vector_get(&backend->packs, i);
+		if (p == backend->last_found)
+			continue;
 
+		if (pack_entry_find1(e, p, oid) == GIT_SUCCESS) {
+			backend->last_found = p;
 			return GIT_SUCCESS;
 		}
+	}
+
+	return GIT_ENOTFOUND;
+}
 
-		case GIT_OBJ_REF_DELTA: {
 
-			git_oid base_id;
-			uint32_t n;
-			index_entry entry;
-			int res = GIT_ERROR;
 
-			git_oid_mkraw(&base_id, buffer);
 
-			if (!p->idx_search(&n, p, &base_id) &&
-				!p->idx_get(&entry, p, n)) {
 
-				res = unpack_object_delta(out, p, &entry,
-					buffer + GIT_OID_RAWSZ, deflated_size, inflated_size);
-			}
 
-			return res;
-		}
 
-		default:
-			return GIT_EOBJCORRUPTED;
-	}
-}
 
-static int read_packed(git_rawobj *out, const pack_location *loc)
-{
-	index_entry e;
-	int res;
 
-	assert(out && loc);
 
-	if (pack_openidx(loc->ptr) < 0)
-		return GIT_EPACKCORRUPTED;
 
-	res = loc->ptr->idx_get(&e, loc->ptr, loc->n);
 
-	if (!res)
-		res = unpack_object(out, loc->ptr, &e);
+/***********************************************************
+ *
+ * PACKFILE ENTRY UNPACK INTERNALS
+ *
+ ***********************************************************/
+
+static unsigned long packfile_unpack_header1(
+		size_t *sizep,
+		git_otype *type, 
+		const unsigned char *buf,
+		unsigned long len)
+{
+	unsigned shift;
+	unsigned long size, c;
+	unsigned long used = 0;
+
+	c = buf[used++];
+	*type = (c >> 4) & 7;
+	size = c & 15;
+	shift = 4;
+	while (c & 0x80) {
+		if (len <= used || bitsizeof(long) <= shift)
+			return 0;
 
-	pack_decidx(loc->ptr);
+		c = buf[used++];
+		size += (c & 0x7f) << shift;
+		shift += 7;
+	}
 
-	return res;
+	*sizep = (size_t)size;
+	return used;
 }
 
-static int read_header_packed(git_rawobj *out, const pack_location *loc)
+static int packfile_unpack_header(
+		size_t *size_p,
+		git_otype *type_p,
+		struct pack_backend *backend,
+		struct pack_file *p,
+		struct pack_window **w_curs,
+		off_t *curpos)
 {
-	git_pack *pack;
-	index_entry e;
-	int error = GIT_SUCCESS, shift;
-	uint8_t *buffer, byte;
+	unsigned char *base;
+	unsigned int left;
+	unsigned long used;
+
+	/* pack_window_open() assures us we have [base, base + 20) available
+	 * as a range that we can look at at.  (Its actually the hash
+	 * size that is assured.)  With our object header encoding
+	 * the maximum deflated object size is 2^137, which is just
+	 * insane, so we know won't exceed what we have been given.
+	 */
+	base = pack_window_open(backend, p, w_curs, *curpos, &left);
+	if (base == NULL)
+		return GIT_ENOMEM;
 
-	assert(out && loc);
+	used = packfile_unpack_header1(size_p, type_p, base, left);
 
-	pack = loc->ptr;
+	if (used == 0)
+		return GIT_EOBJCORRUPTED;
 
-	if (pack_openidx(pack))
-		return GIT_EPACKCORRUPTED;
+	*curpos += used;
+	return GIT_SUCCESS;
+}
 
-	if (pack->idx_get(&e, pack, loc->n) < 0 ||
-		open_pack(pack) < 0) {
-		error = GIT_ENOTFOUND;
-		goto cleanup;
+static int packfile_unpack_compressed(
+		git_rawobj *obj,
+		struct pack_backend *backend,
+		struct pack_file *p,
+		struct pack_window **w_curs,
+		off_t curpos,
+		size_t size,
+		git_otype type)
+{
+	int st;
+	z_stream stream;
+	unsigned char *buffer, *in;
+
+	buffer = git__malloc(size);
+
+	memset(&stream, 0, sizeof(stream));
+	stream.next_out = buffer;
+	stream.avail_out = size + 1;
+
+	st = inflateInit(&stream);
+	if (st != Z_OK) {
+		free(buffer);
+		return GIT_EZLIB;
 	}
 
-	buffer = (uint8_t *)pack->pack_map.data + e.offset;
+	do {
+		in = pack_window_open(backend, p, w_curs, curpos, &stream.avail_in);
+		stream.next_in = in;
+		st = inflate(&stream, Z_FINISH);
 
-	byte = *buffer++ & 0xFF;
-	out->type = (byte >> 4) & 0x7;
-	out->len = byte & 0xF;
-	shift = 4;
+		if (!stream.avail_out)
+			break; /* the payload is larger than it should be */
 
-	while (byte & 0x80) {
-		byte = *buffer++ & 0xFF;
-		out->len += (byte & 0x7F) << shift;
-		shift += 7;
+		curpos += stream.next_in - in;
+	} while (st == Z_OK || st == Z_BUF_ERROR);
+
+	inflateEnd(&stream);
+
+	if ((st != Z_STREAM_END) || stream.total_out != size) {
+		free(buffer);
+		return GIT_EZLIB;
 	}
 
-	/*
-	 * FIXME: if the object is not packed as a whole,
-	 * we need to do a full load and apply the deltas before
-	 * being able to read the header.
-	 *
-	 * I don't think there are any workarounds for this.'
+	obj->type = type;
+	obj->len = size;
+	obj->data = buffer;
+	return GIT_SUCCESS;
+}
+
+static off_t get_delta_base(
+		struct pack_backend *backend,
+		struct pack_file *p,
+		struct pack_window **w_curs,
+		off_t *curpos,
+		git_otype type,
+		off_t delta_obj_offset)
+{
+	unsigned char *base_info = pack_window_open(backend, p, w_curs, *curpos, NULL);
+	off_t base_offset;
+
+	/* pack_window_open() assured us we have [base_info, base_info + 20)
+	 * as a range that we can look at without walking off the
+	 * end of the mapped window.  Its actually the hash size
+	 * that is assured.  An OFS_DELTA longer than the hash size
+	 * is stupid, as then a REF_DELTA would be smaller to store.
 	 */
+	if (type == GIT_OBJ_OFS_DELTA) {
+		unsigned used = 0;
+		unsigned char c = base_info[used++];
+		base_offset = c & 127;
+		while (c & 128) {
+			base_offset += 1;
+			if (!base_offset || MSB(base_offset, 7))
+				return 0;  /* overflow */
+			c = base_info[used++];
+			base_offset = (base_offset << 7) + (c & 127);
+		}
+		base_offset = delta_obj_offset - base_offset;
+		if (base_offset <= 0 || base_offset >= delta_obj_offset)
+			return 0;  /* out of bound */
+		*curpos += used;
+	} else if (type == GIT_OBJ_REF_DELTA) {
+		/* The base entry _must_ be in the same pack */
+		if (pack_entry_find_offset(&base_offset, p, (git_oid *)base_info) < GIT_SUCCESS)
+			return GIT_EPACKCORRUPTED;
+		*curpos += 20;
+	} else
+		return 0;
+
+	return base_offset;
+}
 
-	if (out->type == GIT_OBJ_OFS_DELTA || out->type == GIT_OBJ_REF_DELTA) {
-		error = unpack_object(out, pack, &e);
-		git_rawobj_close(out);
+static int packfile_unpack_delta(
+		git_rawobj *obj,
+		struct pack_backend *backend,
+		struct pack_file *p,
+		struct pack_window **w_curs,
+		off_t curpos,
+		size_t delta_size,
+		git_otype delta_type,
+		off_t obj_offset)
+{
+	off_t base_offset;
+	git_rawobj base, delta;
+	int error;
+
+	base_offset = get_delta_base(backend, p, w_curs, &curpos, delta_type, obj_offset);
+	if (base_offset == 0)
+		return GIT_EOBJCORRUPTED;
+
+	pack_window_close(w_curs);
+	error = packfile_unpack(&base, backend, p, base_offset);
+
+	/* TODO: git.git tries to load the base from other packfiles
+	 * or loose objects */
+	if (error < GIT_SUCCESS)
+		return error;
+
+	error = packfile_unpack_compressed(&delta, backend, p, w_curs, curpos, delta_size, delta_type);
+	if (error < GIT_SUCCESS) {
+		free(base.data);
+		return error;
 	}
 
-cleanup:
-	pack_decidx(loc->ptr);
+	obj->type = base.type;
+	error = git__delta_apply(obj,
+			base.data, base.len,
+			delta.data, delta.len);
+
+	free(base.data);
+	free(delta.data);
+
+	/* TODO: we might want to cache this shit. eventually */
+	//add_delta_base_cache(p, base_offset, base, base_size, *type);
 	return error;
 }
 
+static int packfile_unpack(
+		git_rawobj *obj,
+		struct pack_backend *backend,
+		struct pack_file *p,
+		off_t obj_offset)
+{
+	struct pack_window *w_curs = NULL;
+	off_t curpos = obj_offset;
+	int error;
+
+	size_t size;
+	git_otype type;
+
+	/* 
+	 * TODO: optionally check the CRC on the packfile
+	 */
 
+	obj->data = NULL;
+	obj->len = 0;
+	obj->type = GIT_OBJ_BAD;
+
+	error = packfile_unpack_header(&size, &type, backend, p, &w_curs, &curpos);
+	if (error < GIT_SUCCESS)
+		return error;
+
+	switch (type) {
+	case GIT_OBJ_OFS_DELTA:
+	case GIT_OBJ_REF_DELTA:
+		error = packfile_unpack_delta(
+				obj, backend, p, &w_curs, curpos,
+				size, type, obj_offset);
+		break;
+
+	case GIT_OBJ_COMMIT:
+	case GIT_OBJ_TREE:
+	case GIT_OBJ_BLOB:
+	case GIT_OBJ_TAG:
+		error = packfile_unpack_compressed(
+				obj, backend, p, &w_curs, curpos,
+				size, type);
+		break;
+
+	default:
+		error = GIT_EOBJCORRUPTED;
+		break;
+	}
+
+	pack_window_close(&w_curs);
+	return error;
+}
 
 
 
@@ -1126,80 +1323,88 @@ cleanup:
  *
  ***********************************************************/
 
+/*
 int pack_backend__read_header(git_rawobj *obj, git_odb_backend *backend, const git_oid *oid)
 {
 	pack_location location;
 
 	assert(obj && backend && oid);
 
-	if (locate_packfile(&location, (pack_backend *)backend, oid) < 0)
+	if (locate_packfile(&location, (struct pack_backend *)backend, oid) < 0)
 		return GIT_ENOTFOUND;
 
 	return read_header_packed(obj, &location);
 }
+*/
 
-int pack_backend__read(git_rawobj *obj, git_odb_backend *backend, const git_oid *oid)
+int pack_backend__read(void **buffer_p, size_t *len_p, git_otype *type_p, git_odb_backend *backend, const git_oid *oid)
 {
-	pack_location location;
+	struct pack_entry e;
+	git_rawobj raw;
+	int error;
 
-	assert(obj && backend && oid);
+	if ((error = pack_entry_find(&e, (struct pack_backend *)backend, oid)) < GIT_SUCCESS)
+		return error;
 
-	if (locate_packfile(&location, (pack_backend *)backend, oid) < 0)
-		return GIT_ENOTFOUND;
+	if ((error = packfile_unpack(&raw, (struct pack_backend *)backend, e.p, e.offset)) < GIT_SUCCESS)
+		return error;
 
-	return read_packed(obj, &location);
+	*buffer_p = raw.data;
+	*len_p = raw.len;
+	*type_p = raw.type;
+
+	return GIT_SUCCESS;
 }
 
 int pack_backend__exists(git_odb_backend *backend, const git_oid *oid)
 {
-	pack_location location;
-	assert(backend && oid);
-	return locate_packfile(&location, (pack_backend *)backend, oid) == GIT_SUCCESS;
+	struct pack_entry e;
+	return pack_entry_find(&e, (struct pack_backend *)backend, oid) == GIT_SUCCESS;
 }
 
 void pack_backend__free(git_odb_backend *_backend)
 {
-	pack_backend *backend;
-	git_packlist *pl;
+	struct pack_backend *backend;
+	size_t i;
 
 	assert(_backend);
 
-	backend = (pack_backend *)_backend;
-
-	gitlck_lock(&backend->lock);
-
-	pl = backend->packlist;
-	backend->packlist = NULL;
+	backend = (struct pack_backend *)_backend;
 
-	gitlck_unlock(&backend->lock);
-	if (pl)
-		packlist_dec(backend, pl);
-
-	gitlck_free(&backend->lock);
+	for (i = 0; i < backend->packs.length; ++i) {
+		struct pack_file *p = git_vector_get(&backend->packs, i);
+		packfile_free(backend, p);
+	}
 
-	free(backend->objects_dir);
+	git_vector_free(&backend->packs);
 	free(backend);
 }
 
 int git_odb_backend_pack(git_odb_backend **backend_out, const char *objects_dir)
 {
-	pack_backend *backend;
+	int error;
+	struct pack_backend *backend;
 
-	backend = git__calloc(1, sizeof(pack_backend));
+	backend = git__calloc(1, sizeof(struct pack_backend));
 	if (backend == NULL)
 		return GIT_ENOMEM;
 
-	backend->objects_dir = git__strdup(objects_dir);
-	if (backend->objects_dir == NULL) {
+	if (git_vector_init(&backend->packs, 8, packfile_sort__cb) < GIT_SUCCESS) {
 		free(backend);
 		return GIT_ENOMEM;
 	}
 
-	gitlck_init(&backend->lock);
+	backend->window_size = DEFAULT_WINDOW_SIZE;
+	backend->mapped_limit = DEFAULT_MAPPED_LIMIT;
+
+	error = packfile_load_all(backend, objects_dir, 1);
+	if (error < GIT_SUCCESS) {
+		pack_backend__free((git_odb_backend *)backend);
+		return error;
+	}
 
 	backend->parent.read = &pack_backend__read;
-	backend->parent.read_header = &pack_backend__read_header;
-	backend->parent.write = NULL;
+	backend->parent.read_header = NULL;
 	backend->parent.exists = &pack_backend__exists;
 	backend->parent.free = &pack_backend__free;
 
diff --git a/src/oid.c b/src/oid.c
index 81b7d6005..eb167a685 100644
--- a/src/oid.c
+++ b/src/oid.c
@@ -143,14 +143,18 @@ int git__parse_oid(git_oid *oid, char **buffer_out,
 	return GIT_SUCCESS;
 }
 
-int git__write_oid(git_odb_source *src, const char *header, const git_oid *oid)
+int git__write_oid(git_odb_stream *stream, const char *header, const git_oid *oid)
 {
-	char hex_oid[41];
+	char hex_oid[42];
 
-	git_oid_fmt(hex_oid, oid);
-	hex_oid[40] = 0;
+	git_oid_fmt(hex_oid + 1, oid);
 
-	return git__source_printf(src, "%s %s\n", header, hex_oid);
+	hex_oid[0] = ' ';
+	hex_oid[41] = '\n';
+
+	stream->write(stream, header, strlen(header));
+	stream->write(stream, hex_oid, 42);
+	return GIT_SUCCESS;
 }
 
 void git_oid_mkraw(git_oid *out, const unsigned char *raw)
diff --git a/src/pqueue.c b/src/pqueue.c
new file mode 100644
index 000000000..6307175e3
--- /dev/null
+++ b/src/pqueue.c
@@ -0,0 +1,157 @@
+/*
+ *	BORING COPYRIGHT NOTICE:
+ *
+ *	This file is a heavily modified version of the priority queue found
+ *	in the Apache project and the libpqueue library.
+ *
+ *		https://github.com/vy/libpqueue
+ *
+ *	These are the original authors:
+ *
+ *		Copyright 2010 Volkan Yazıcı <volkan.yazici@gmail.com>
+ *		Copyright 2006-2010 The Apache Software Foundation
+ *
+ *  This file is licensed under the Apache 2.0 license, which 
+ *  supposedly makes it compatible with the GPLv2 that libgit2 uses.
+ *
+ *  Check the Apache license at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  So much licensing trouble for a binary heap. Oh well.
+ */
+
+#include "common.h"
+#include "pqueue.h"
+
+#define left(i)   ((i) << 1)
+#define right(i)  (((i) << 1) + 1)
+#define parent(i) ((i) >> 1)
+
+int git_pqueue_init(git_pqueue *q, size_t n, git_pqueue_cmp cmppri)
+{
+	assert(q);
+
+    /* Need to allocate n+1 elements since element 0 isn't used. */
+    if ((q->d = malloc((n + 1) * sizeof(void *))) == NULL)
+		return GIT_ENOMEM;
+
+    q->size = 1;
+    q->avail = q->step = (n + 1);  /* see comment above about n+1 */
+    q->cmppri = cmppri;
+
+    return GIT_SUCCESS;
+}
+
+
+void git_pqueue_free(git_pqueue *q)
+{
+    free(q->d);
+	q->d = NULL;
+}
+
+void git_pqueue_clear(git_pqueue *q)
+{
+	q->size = 1;
+}
+
+size_t git_pqueue_size(git_pqueue *q)
+{
+    /* queue element 0 exists but doesn't count since it isn't used. */
+    return (q->size - 1);
+}
+
+
+static void bubble_up(git_pqueue *q, size_t i)
+{
+    size_t parent_node;
+    void *moving_node = q->d[i];
+
+    for (parent_node = parent(i);
+         ((i > 1) && q->cmppri(q->d[parent_node], moving_node));
+         i = parent_node, parent_node = parent(i)) {
+        q->d[i] = q->d[parent_node];
+    }
+
+    q->d[i] = moving_node;
+}
+
+
+static size_t maxchild(git_pqueue *q, size_t i)
+{
+    size_t child_node = left(i);
+
+    if (child_node >= q->size)
+        return 0;
+
+    if ((child_node + 1) < q->size &&
+        q->cmppri(q->d[child_node], q->d[child_node + 1]))
+        child_node++; /* use right child instead of left */
+
+    return child_node;
+}
+
+
+static void percolate_down(git_pqueue *q, size_t i)
+{
+    size_t child_node;
+    void *moving_node = q->d[i];
+
+    while ((child_node = maxchild(q, i)) != 0 &&
+           q->cmppri(moving_node, q->d[child_node])) {
+        q->d[i] = q->d[child_node];
+        i = child_node;
+    }
+
+    q->d[i] = moving_node;
+}
+
+
+int git_pqueue_insert(git_pqueue *q, void *d)
+{
+    void *tmp;
+    size_t i;
+    size_t newsize;
+
+    if (!q) return 1;
+
+    /* allocate more memory if necessary */
+    if (q->size >= q->avail) {
+        newsize = q->size + q->step;
+        if ((tmp = realloc(q->d, sizeof(void *) * newsize)) == NULL)
+            return GIT_ENOMEM;
+
+        q->d = tmp;
+        q->avail = newsize;
+    }
+
+    /* insert item */
+    i = q->size++;
+    q->d[i] = d;
+    bubble_up(q, i);
+
+    return GIT_SUCCESS;
+}
+
+
+void *git_pqueue_pop(git_pqueue *q)
+{
+    void *head;
+
+    if (!q || q->size == 1)
+        return NULL;
+
+    head = q->d[1];
+    q->d[1] = q->d[--q->size];
+    percolate_down(q, 1);
+
+    return head;
+}
+
+
+void *git_pqueue_peek(git_pqueue *q)
+{
+    if (!q || q->size == 1)
+        return NULL;
+    return q->d[1];
+}
diff --git a/src/pqueue.h b/src/pqueue.h
new file mode 100644
index 000000000..7a1394803
--- /dev/null
+++ b/src/pqueue.h
@@ -0,0 +1,97 @@
+/*
+ *	BORING COPYRIGHT NOTICE:
+ *
+ *	This file is a heavily modified version of the priority queue found
+ *	in the Apache project and the libpqueue library.
+ *
+ *		https://github.com/vy/libpqueue
+ *
+ *	These are the original authors:
+ *
+ *		Copyright 2010 Volkan Yazıcı <volkan.yazici@gmail.com>
+ *		Copyright 2006-2010 The Apache Software Foundation
+ *
+ *  This file is licensed under the Apache 2.0 license, which 
+ *  supposedly makes it compatible with the GPLv2 that libgit2 uses.
+ *
+ *  Check the Apache license at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  So much licensing trouble for a binary heap. Oh well.
+ */
+
+#ifndef INCLUDE_pqueue_h__
+#define INCLUDE_pqueue_h__
+
+/** callback functions to get/set/compare the priority of an element */
+typedef int (*git_pqueue_cmp)(void *a, void *b);
+
+/** the priority queue handle */
+typedef struct {
+    size_t size, avail, step;
+    git_pqueue_cmp cmppri;
+    void **d;
+} git_pqueue;
+
+
+/**
+ * initialize the queue
+ *
+ * @param n the initial estimate of the number of queue items for which memory
+ *          should be preallocated
+ * @param cmppri the callback function to compare two nodes of the queue
+ *
+ * @Return the handle or NULL for insufficent memory
+ */
+int git_pqueue_init(git_pqueue *q, size_t n, git_pqueue_cmp cmppri);
+
+
+/**
+ * free all memory used by the queue
+ * @param q the queue
+ */
+void git_pqueue_free(git_pqueue *q);
+
+/**
+ * clear all the elements in the queue
+ * @param q the queue
+ */
+void git_pqueue_clear(git_pqueue *q);
+
+/**
+ * return the size of the queue.
+ * @param q the queue
+ */
+size_t git_pqueue_size(git_pqueue *q);
+
+
+/**
+ * insert an item into the queue.
+ * @param q the queue
+ * @param d the item
+ * @return 0 on success
+ */
+int git_pqueue_insert(git_pqueue *q, void *d);
+
+
+/**
+ * pop the highest-ranking item from the queue.
+ * @param p the queue
+ * @param d where to copy the entry to
+ * @return NULL on error, otherwise the entry
+ */
+void *git_pqueue_pop(git_pqueue *q);
+
+
+/**
+ * access highest-ranking item without removing it.
+ * @param q the queue
+ * @param d the entry
+ * @return NULL on error, otherwise the entry
+ */
+void *git_pqueue_peek(git_pqueue *q);
+
+#endif /* PQUEUE_H */
+/** @} */
+
diff --git a/src/refs.c b/src/refs.c
index 2fc383e22..9661988cc 100644
--- a/src/refs.c
+++ b/src/refs.c
@@ -59,16 +59,16 @@ static uint32_t reftable_hash(const void *key, int hash_id)
 
 static void reference_free(git_reference *reference);
 static int reference_create(git_reference **ref_out, git_repository *repo, const char *name, git_rtype type);
+static int reference_read(gitfo_buf *file_content, time_t *mtime, const char *repo_path, const char *ref_name);
 
 /* loose refs */
 static int loose_parse_symbolic(git_reference *ref, gitfo_buf *file_content);
 static int loose_parse_oid(git_reference *ref, gitfo_buf *file_content);
-static int loose_read(gitfo_buf *file_content, const char *name, const char *repo_path);
-static int loose_lookup( git_reference **ref_out, git_repository *repo, const char *name, int skip_symbolic);
+static int loose_lookup(git_reference **ref_out, git_repository *repo, const char *name, int skip_symbolic);
 static int loose_write(git_reference *ref);
+static int loose_update(git_reference *ref);
 
 /* packed refs */
-static int packed_readpack(gitfo_buf *packfile, const char *repo_path);
 static int packed_parse_peel(reference_oid *tag_ref, const char **buffer_out, const char *buffer_end);
 static int packed_parse_oid(reference_oid **ref_out, git_repository *repo, const char **buffer_out, const char *buffer_end);
 static int packed_load(git_repository *repo);
@@ -79,6 +79,11 @@ static int packed_remove_loose(git_repository *repo, git_vector *packing_list);
 static int packed_sort(const void *a, const void *b);
 static int packed_write(git_repository *repo);
 
+/* internal helpers */
+static int reference_create_symbolic(git_reference **ref_out, git_repository *repo, const char *name, const char *target, int force);
+static int reference_create_oid(git_reference **ref_out, git_repository *repo, const char *name, const git_oid *id, int force);
+static int reference_rename(git_reference *ref, const char *new_name, int force);
+
 /* name normalization */
 static int check_valid_ref_char(char ch);
 static int normalize_name(char *buffer_out, const char *name, int is_oid_ref);
@@ -146,12 +151,73 @@ cleanup:
 	return error;
 }
 
+static int reference_read(gitfo_buf *file_content, time_t *mtime, const char *repo_path, const char *ref_name)
+{
+	struct stat st;
+	char path[GIT_PATH_MAX];
+
+	/* Determine the full path of the file */
+	git__joinpath(path, repo_path, ref_name);
+
+	if (gitfo_stat(path, &st) < 0)
+		return GIT_ENOTFOUND;
+
+	if (S_ISDIR(st.st_mode))
+		return GIT_EOBJCORRUPTED;
+
+	if (mtime)
+		*mtime = st.st_mtime;
+
+	if (file_content)
+		return gitfo_read_file(file_content, path);
+
+	return GIT_SUCCESS;
+}
+
 
 
 
 /*****************************************
  * Internal methods - Loose references
  *****************************************/
+static int loose_update(git_reference *ref)
+{
+	int error;
+	time_t ref_time;
+	gitfo_buf ref_file = GITFO_BUF_INIT;
+
+	if (ref->type & GIT_REF_PACKED)
+		return packed_load(ref->owner);
+
+	error = reference_read(NULL, &ref_time, ref->owner->path_repository, ref->name);
+	if (error < GIT_SUCCESS)
+		goto cleanup;
+
+	if (ref_time == ref->mtime)
+		return GIT_SUCCESS;
+
+	error = reference_read(&ref_file, &ref->mtime, ref->owner->path_repository, ref->name);
+	if (error < GIT_SUCCESS)
+		goto cleanup;
+
+	if (ref->type == GIT_REF_SYMBOLIC)
+		error = loose_parse_symbolic(ref, &ref_file);
+	else if (ref->type == GIT_REF_OID)
+		error = loose_parse_oid(ref, &ref_file);
+	else
+		error = GIT_EINVALIDREFSTATE;
+
+	gitfo_free_buf(&ref_file);
+
+cleanup:
+	if (error != GIT_SUCCESS) {
+		reference_free(ref);
+		git_hashtable_remove(ref->owner->references.loose_cache, ref->name);
+	}
+
+	return error;
+}
+
 static int loose_parse_symbolic(git_reference *ref, gitfo_buf *file_content)
 {
 	const unsigned int header_len = strlen(GIT_SYMREF);
@@ -172,6 +238,7 @@ static int loose_parse_symbolic(git_reference *ref, gitfo_buf *file_content)
 
 	refname_start += header_len;
 
+	free(ref_sym->target);
 	ref_sym->target = git__strdup(refname_start);
 	if (ref_sym->target == NULL)
 		return GIT_ENOMEM;
@@ -213,26 +280,23 @@ static int loose_parse_oid(git_reference *ref, gitfo_buf *file_content)
 	return GIT_SUCCESS;
 }
 
-static int loose_read(gitfo_buf *file_content, const char *name, const char *repo_path)
-{
-	int error = GIT_SUCCESS;
-	char ref_path[GIT_PATH_MAX];
-
-	/* Determine the full path of the ref */
-	git__joinpath(ref_path, repo_path, name);
 
-	/* Does it even exist ? */
-	if (gitfo_exists(ref_path) < GIT_SUCCESS)
-		return GIT_ENOTFOUND;
+static git_rtype loose_guess_rtype(const char *full_path)
+{
+	gitfo_buf ref_file = GITFO_BUF_INIT;
+	git_rtype type;
 
-	/* A ref can not be a directory */
-	if (!gitfo_isdir(ref_path))
-		return GIT_ENOTFOUND;
+	type = GIT_REF_INVALID;
 
-	if (file_content != NULL)
-		error = gitfo_read_file(file_content, ref_path);
+	if (gitfo_read_file(&ref_file, full_path) == GIT_SUCCESS) {
+		if (git__prefixcmp((const char *)(ref_file.data), GIT_SYMREF) == 0)
+			type = GIT_REF_SYMBOLIC;
+		else
+			type = GIT_REF_OID;
+	}
 
-	return error;
+	gitfo_free_buf(&ref_file);
+	return type;
 }
 
 static int loose_lookup(
@@ -244,10 +308,11 @@ static int loose_lookup(
 	int error = GIT_SUCCESS;
 	gitfo_buf ref_file = GITFO_BUF_INIT;
 	git_reference *ref = NULL;
+	time_t ref_time;
 
 	*ref_out = NULL;
 
-	error = loose_read(&ref_file, name, repo->path_repository);
+	error = reference_read(&ref_file, &ref_time, repo->path_repository, name);
 	if (error < GIT_SUCCESS)
 		goto cleanup;
 
@@ -271,7 +336,9 @@ static int loose_lookup(
 	if (error < GIT_SUCCESS)
 		goto cleanup;
 
+	ref->mtime = ref_time;
 	*ref_out = ref;
+	gitfo_free_buf(&ref_file);
 	return GIT_SUCCESS;
 
 cleanup:
@@ -286,6 +353,7 @@ static int loose_write(git_reference *ref)
 	char ref_path[GIT_PATH_MAX];
 	int error, contents_size;
 	char *ref_contents = NULL;
+	struct stat st;
 
 	assert((ref->type & GIT_REF_PACKED) == 0);
 
@@ -331,6 +399,9 @@ static int loose_write(git_reference *ref)
 
 	error = git_filebuf_commit(&file);
 
+	if (gitfo_stat(ref_path, &st) == GIT_SUCCESS)
+		ref->mtime = st.st_mtime;
+
 	free(ref_contents);
 	return error;
 
@@ -348,19 +419,6 @@ unlock:
 /*****************************************
  * Internal methods - Packed references
  *****************************************/
-static int packed_readpack(gitfo_buf *packfile, const char *repo_path)
-{
-	char ref_path[GIT_PATH_MAX];
-
-	/* Determine the full path of the file */
-	git__joinpath(ref_path, repo_path, GIT_PACKEDREFS_FILE);
-
-	/* Does it even exist ? */
-	if (gitfo_exists(ref_path) < GIT_SUCCESS)
-		return GIT_ENOTFOUND;
-
-	return gitfo_read_file(packfile, ref_path);
-}
 
 static int packed_parse_peel(
 		reference_oid *tag_ref,
@@ -465,19 +523,40 @@ static int packed_load(git_repository *repo)
 	git_refcache *ref_cache = &repo->references;
 
 	/* already loaded */
-	if (repo->references.packfile != NULL)
-		return GIT_SUCCESS;
+	if (repo->references.packfile != NULL) {
+		time_t packed_time;
 
-	repo->references.packfile = git_hashtable_alloc(
-		default_table_size, 
-		reftable_hash,
-		(git_hash_keyeq_ptr)strcmp);
+		/* check if we can read the time of the index;
+		 * if we can read it and it matches the time of the
+		 * index we had previously loaded, we don't need to do
+		 * anything else.
+		 *
+		 * if we cannot load the time (e.g. the packfile
+		 * has disappeared) or the time is different, we
+		 * have to reload the packfile */
 
-	if (repo->references.packfile == NULL)
-		return GIT_ENOMEM;
+		if (!reference_read(NULL, &packed_time, repo->path_repository, GIT_PACKEDREFS_FILE) &&
+			packed_time == ref_cache->packfile_time)
+			return GIT_SUCCESS;
+
+		git_hashtable_clear(repo->references.packfile);
+	} else {
+		ref_cache->packfile = git_hashtable_alloc(
+			default_table_size, 
+			reftable_hash,
+			(git_hash_keyeq_ptr)strcmp);
+
+		if (ref_cache->packfile == NULL)
+			return GIT_ENOMEM;
+	}
 
-	/* read the packfile from disk */
-	error = packed_readpack(&packfile, repo->path_repository);
+	/* read the packfile from disk;
+	 * store its modification time to check for future reloads */
+	error = reference_read(
+			&packfile,
+			&ref_cache->packfile_time,
+			repo->path_repository,
+			GIT_PACKEDREFS_FILE);
 
 	/* there is no packfile on disk; that's ok */
 	if (error == GIT_ENOTFOUND)
@@ -489,22 +568,14 @@ static int packed_load(git_repository *repo)
 	buffer_start = (const char *)packfile.data;
 	buffer_end = (const char *)(buffer_start) + packfile.len;
 
-	/* Does the header look like valid? */
-	if (git__prefixcmp((const char *)(buffer_start), GIT_PACKEDREFS_HEADER)) {
-		error = GIT_EPACKEDREFSCORRUPTED;
-		goto cleanup;
-	}
-
-	/* Let's skip the header */
-	buffer_start += strlen(GIT_PACKEDREFS_HEADER);
-
-	if (*buffer_start == '\r')
+	while (buffer_start < buffer_end && buffer_start[0] == '#') {
+		buffer_start = strchr(buffer_start, '\n');
+		if (buffer_start == NULL) {
+			error = GIT_EPACKEDREFSCORRUPTED;
+			goto cleanup;
+		}
 		buffer_start++;
-
-	if (*buffer_start != '\n')
-		return GIT_EPACKEDREFSCORRUPTED;
-
-	buffer_start++;
+	}
 
 	while (buffer_start < buffer_end) {
 		reference_oid *ref = NULL;
@@ -526,11 +597,49 @@ static int packed_load(git_repository *repo)
 		}
 	}
 
+	gitfo_free_buf(&packfile);
+	return GIT_SUCCESS;
+
 cleanup:
+	git_hashtable_free(ref_cache->packfile);
+	ref_cache->packfile = NULL;
 	gitfo_free_buf(&packfile);
 	return error;
 }
 
+
+
+
+struct dirent_list_data {
+	git_repository *repo;
+	size_t repo_path_len;
+	unsigned int list_flags;
+
+	int (*callback)(const char *, void *);
+	void *callback_payload;
+};
+
+static int _dirent_loose_listall(void *_data, char *full_path)
+{
+	struct dirent_list_data *data = (struct dirent_list_data *)_data;
+	char *file_path = full_path + data->repo_path_len;
+
+	if (gitfo_isdir(full_path) == GIT_SUCCESS)
+		return gitfo_dirent(full_path, GIT_PATH_MAX, _dirent_loose_listall, _data);
+
+	/* do not add twice a reference that exists already in the packfile */
+	if ((data->list_flags & GIT_REF_PACKED) != 0 &&
+		git_hashtable_lookup(data->repo->references.packfile, file_path) != NULL)
+		return GIT_SUCCESS;
+
+	if (data->list_flags != GIT_REF_LISTALL) {
+		if ((data->list_flags & loose_guess_rtype(full_path)) == 0)
+			return GIT_SUCCESS; /* we are filtering out this reference */
+	}
+
+	return data->callback(file_path, data->callback_payload);
+}
+
 static int _dirent_loose_load(void *data, char *full_path)
 {
 	git_repository *repository = (git_repository *)data;
@@ -638,7 +747,6 @@ static int packed_write_ref(reference_oid *ref, git_filebuf *file)
 static int packed_find_peel(reference_oid *ref)
 {
 	git_tag *tag;
-	const git_object *peeled_target;
 	int error;
 
 	if (ref->ref.type & GIT_REF_HAS_PEEL)
@@ -663,11 +771,7 @@ static int packed_find_peel(reference_oid *ref)
 	/*
 	 * Find the object pointed at by this tag
 	 */
-	peeled_target = git_tag_target(tag);
-	if (peeled_target == NULL)
-		return GIT_EOBJCORRUPTED;
-
-	git_oid_cpy(&ref->peel_target, git_object_id(peeled_target));
+	git_oid_cpy(&ref->peel_target, git_tag_target_oid(tag));
 	ref->ref.type |= GIT_REF_HAS_PEEL;
 
 	/* 
@@ -772,7 +876,9 @@ static int packed_write(git_repository *repo)
 	if ((error = git_filebuf_open(&pack_file, pack_file_path, 0)) < GIT_SUCCESS)
 		return error;
 
-	/* Packfiles have a header! */
+	/* Packfiles have a header... apparently
+	 * This is in fact not required, but we might as well print it
+	 * just for kicks */
 	if ((error = git_filebuf_printf(&pack_file, "%s\n", GIT_PACKEDREFS_HEADER)) < GIT_SUCCESS)
 		return error;
 
@@ -798,8 +904,14 @@ cleanup:
 
 		/* when and only when the packfile has been properly written,
 		 * we can go ahead and remove the loose refs */
-		if (error == GIT_SUCCESS)
+		if (error == GIT_SUCCESS) {
+			struct stat st;
+
 			error = packed_remove_loose(repo, &packing_list);
+
+			if (gitfo_stat(pack_file_path, &st) == GIT_SUCCESS)
+				repo->references.packfile_time = st.st_mtime;
+		}
 	}
 	else git_filebuf_cleanup(&pack_file);
 
@@ -808,8 +920,240 @@ cleanup:
 	return error;
 }
 
+/*****************************************
+ * Internal methods - reference creation
+ *****************************************/
+
+static int reference_create_symbolic(git_reference **ref_out, git_repository *repo, const char *name, const char *target, int force)
+{
+	char normalized[MAX_GITDIR_TREE_STRUCTURE_PATH_LENGTH];
+	int error = GIT_SUCCESS, updated = 0;
+	git_reference *ref = NULL, *old_ref = NULL;
+
+	if (git_reference_lookup(&ref, repo, name) == GIT_SUCCESS && !force)
+		return GIT_EEXISTS;
+
+	/*
+	 * If they old ref was of the same type, then we can just update
+	 * it (once we've checked that the target is valid). Otherwise we
+	 * need a new reference because we can't make a symbolic ref out
+	 * of an oid one.
+	 * If if didn't exist, then we need to create a new one anyway.
+     */
+	if (ref && ref->type & GIT_REF_SYMBOLIC){
+		updated = 1;
+	} else {
+		ref = NULL;
+		error = reference_create(&ref, repo, name, GIT_REF_SYMBOLIC);
+		if (error < GIT_SUCCESS)
+			goto cleanup;
+	}
+
+	/* The target can aither be the name of an object id reference or the name of another symbolic reference */
+	error = normalize_name(normalized, target, 0);
+	if (error < GIT_SUCCESS)
+		goto cleanup;
+
+	/* set the target; this will write the reference on disk */
+	error = git_reference_set_target(ref, normalized);
+	if (error < GIT_SUCCESS)
+		goto cleanup;
+
+	/*
+	 * If we didn't update the ref, then we need to insert or replace
+	 * it in the loose cache. If we replaced a ref, free it.
+	 */
+	if (!updated){
+		error = git_hashtable_insert2(repo->references.loose_cache, ref->name, ref, (void **) &old_ref);
+		if (error < GIT_SUCCESS)
+			goto cleanup;
+
+		if(old_ref)
+			reference_free(old_ref);
+	}
+
+	*ref_out = ref;
+
+	return error;
+
+cleanup:
+	reference_free(ref);
+	return error;
+}
+
+static int reference_create_oid(git_reference **ref_out, git_repository *repo, const char *name, const git_oid *id, int force)
+{
+	int error = GIT_SUCCESS, updated = 0;
+	git_reference *ref = NULL, *old_ref = NULL;
+
+	if(git_reference_lookup(&ref, repo, name) == GIT_SUCCESS && !force)
+		return GIT_EEXISTS;
+
+	/*
+	 * If they old ref was of the same type, then we can just update
+	 * it (once we've checked that the target is valid). Otherwise we
+	 * need a new reference because we can't make a symbolic ref out
+	 * of an oid one.
+	 * If if didn't exist, then we need to create a new one anyway.
+     */
+	if (ref && ref-> type & GIT_REF_OID){
+		updated = 1;
+	} else {
+		ref = NULL;
+		error = reference_create(&ref, repo, name, GIT_REF_OID);
+		if (error < GIT_SUCCESS)
+			goto cleanup;
+	}
+
+	/* set the oid; this will write the reference on disk */
+	error = git_reference_set_oid(ref, id);
+	if (error < GIT_SUCCESS)
+		goto cleanup;
+
+	if(!updated){
+		error = git_hashtable_insert2(repo->references.loose_cache, ref->name, ref, (void **) &old_ref);
+		if (error < GIT_SUCCESS)
+			goto cleanup;
+
+		if(old_ref)
+			reference_free(old_ref);
+	}
+
+	*ref_out = ref;
+
+	return error;
+
+cleanup:
+	reference_free(ref);
+	return error;
+}
+
+/*
+ * Rename a reference
+ *
+ * If the reference is packed, we need to rewrite the
+ * packfile to remove the reference from it and create
+ * the reference back as a loose one.
+ *
+ * If the reference is loose, we just rename it on
+ * the filesystem.
+ *
+ * We also need to re-insert the reference on its corresponding
+ * in-memory cache, since the caches are indexed by refname.
+ */
+static int reference_rename(git_reference *ref, const char *new_name, int force)
+{
+	int error;
+	char *old_name;
+	char old_path[GIT_PATH_MAX], new_path[GIT_PATH_MAX], normalized_name[MAX_GITDIR_TREE_STRUCTURE_PATH_LENGTH];
+	git_reference *looked_up_ref, *old_ref = NULL;
+
+	assert(ref);
+
+	/* Ensure the name is valid */
+	error = normalize_name(normalized_name, new_name, ref->type & GIT_REF_OID);
+	if (error < GIT_SUCCESS)
+		return error;
+
+	/* Ensure we're not going to overwrite an existing reference
+	   unless the user has allowed us */
+	error = git_reference_lookup(&looked_up_ref, ref->owner, new_name);
+	if (error == GIT_SUCCESS && !force)
+		return GIT_EEXISTS;
+
+	if (error < GIT_SUCCESS &&
+	    error != GIT_ENOTFOUND)
+		return error;
+
+
+	old_name = ref->name;
+	ref->name = git__strdup(new_name);
+
+	if (ref->name == NULL) {
+		ref->name = old_name;
+		return GIT_ENOMEM;
+	}
+
+	if (ref->type & GIT_REF_PACKED) {
+		/* write the packfile to disk; note
+		 * that the state of the in-memory cache is not
+		 * consistent, because the reference is indexed
+		 * by its old name but it already has the new one.
+		 * This doesn't affect writing, though, and allows
+		 * us to rollback if writing fails
+		 */
+
+		ref->type &= ~GIT_REF_PACKED;
+
+		/* Create the loose ref under its new name */
+		error = loose_write(ref);
+		if (error < GIT_SUCCESS) {
+			ref->type |= GIT_REF_PACKED;
+			goto cleanup;
+		}
+
+		/* Remove from the packfile cache in order to avoid packing it back
+		 * Note : we do not rely on git_reference_delete() because this would
+		 * invalidate the reference.
+		 */
+		git_hashtable_remove(ref->owner->references.packfile, old_name);
+
+		/* Recreate the packed-refs file without the reference */
+		error = packed_write(ref->owner);
+		if (error < GIT_SUCCESS)
+			goto rename_loose_to_old_name;
+
+	} else {
+		git__joinpath(old_path, ref->owner->path_repository, old_name);
+		git__joinpath(new_path, ref->owner->path_repository, ref->name);
+
+		error = gitfo_mv_force(old_path, new_path);
+		if (error < GIT_SUCCESS)
+			goto cleanup;
+
+		/* Once succesfully renamed, remove from the cache the reference known by its old name*/
+		git_hashtable_remove(ref->owner->references.loose_cache, old_name);
+	}
+
+	/* Store the renamed reference into the loose ref cache */
+	error = git_hashtable_insert2(ref->owner->references.loose_cache, ref->name, ref, (void **) &old_ref);
+
+	/* If we force-replaced, we need to free the old reference */
+	if(old_ref)
+		reference_free(old_ref);
+
+	free(old_name);
+	return error;
+
+cleanup:
+	/* restore the old name if this failed */
+	free(ref->name);
+	ref->name = old_name;
+	return error;
+
+rename_loose_to_old_name:
+	/* If we hit this point. Something *bad* happened! Think "Ghostbusters
+	 * crossing the streams" definition of bad.
+	 * Either the packed-refs has been correctly generated and something else
+	 * has gone wrong, or the writing of the new packed-refs has failed, and
+	 * we're stuck with the old one. As a loose ref always takes priority over
+	 * a packed ref, we'll eventually try and rename the generated loose ref to
+	 * its former name. It even that fails, well... we might have lost the reference
+	 * for good. :-/
+	*/
+
+	git__joinpath(old_path, ref->owner->path_repository, ref->name);
+	git__joinpath(new_path, ref->owner->path_repository, old_name);
+
+	/* No error checking. We'll return the initial error */
+	gitfo_mv_force(old_path, new_path);
 
+	/* restore the old name */
+	free(ref->name);
+	ref->name = old_name;
 
+	return error;
+}
 
 /*****************************************
  * External Library API
@@ -834,7 +1178,7 @@ int git_reference_lookup(git_reference **ref_out, git_repository *repo, const ch
 	/* First, check has been previously loaded and cached */
 	*ref_out = git_hashtable_lookup(repo->references.loose_cache, normalized_name);
 	if (*ref_out != NULL)
-		return GIT_SUCCESS;
+		return loose_update(*ref_out);
 
 	/* Then check if there is a loose file for that reference.*/
 	error = loose_lookup(ref_out, repo, normalized_name, 0);
@@ -852,12 +1196,10 @@ int git_reference_lookup(git_reference **ref_out, git_repository *repo, const ch
 	 * If we cannot find a loose reference, we look into the packfile
 	 * Load the packfile first if it hasn't been loaded 
 	 */
-	if (!repo->references.packfile) {
-		/* load all the packed references */
-		error = packed_load(repo);
-		if (error < GIT_SUCCESS)
-			return error;
-	}
+	/* load all the packed references */
+	error = packed_load(repo);
+	if (error < GIT_SUCCESS)
+		return error;
 
 	/* Look up on the packfile */
 	*ref_out = git_hashtable_lookup(repo->references.packfile, normalized_name);
@@ -870,64 +1212,23 @@ int git_reference_lookup(git_reference **ref_out, git_repository *repo, const ch
 
 int git_reference_create_symbolic(git_reference **ref_out, git_repository *repo, const char *name, const char *target)
 {
-	char normalized[MAX_GITDIR_TREE_STRUCTURE_PATH_LENGTH];
-	int error = GIT_SUCCESS;
-	git_reference *ref = NULL;
-
-	error = reference_create(&ref, repo, name, GIT_REF_SYMBOLIC);
-	if (error < GIT_SUCCESS)
-		goto cleanup;
-
-	/* The target can aither be the name of an object id reference or the name of another symbolic reference */
-	error = normalize_name(normalized, target, 0);
-	if (error < GIT_SUCCESS)
-		goto cleanup;
-
-	/* set the target; this will write the reference on disk */
-	error = git_reference_set_target(ref, normalized);
-	if (error < GIT_SUCCESS)
-		goto cleanup;
-
-	error = git_hashtable_insert(repo->references.loose_cache, ref->name, ref);
-	if (error < GIT_SUCCESS)
-		goto cleanup;
-
-	*ref_out = ref;
-
-	return error;
+	return reference_create_symbolic(ref_out, repo, name, target, 0);
+}
 
-cleanup:
-	reference_free(ref);
-	return error;
+int git_reference_create_symbolic_f(git_reference **ref_out, git_repository *repo, const char *name, const char *target)
+{
+	return reference_create_symbolic(ref_out, repo, name, target, 1);
 }
 
 int git_reference_create_oid(git_reference **ref_out, git_repository *repo, const char *name, const git_oid *id)
 {
-	int error = GIT_SUCCESS;
-	git_reference *ref = NULL;
-
-	error = reference_create(&ref, repo, name, GIT_REF_OID);
-	if (error < GIT_SUCCESS)
-		goto cleanup;
-
-	/* set the oid; this will write the reference on disk */
-	error = git_reference_set_oid(ref, id);
-	if (error < GIT_SUCCESS)
-		goto cleanup;
-
-	error = git_hashtable_insert(repo->references.loose_cache, ref->name, ref);
-	if (error < GIT_SUCCESS)
-		goto cleanup;
-
-	*ref_out = ref;
-
-	return error;
-
-cleanup:
-	reference_free(ref);
-	return error;
+	return reference_create_oid(ref_out, repo, name, id, 0);
 }
 
+int git_reference_create_oid_f(git_reference **ref_out, git_repository *repo, const char *name, const git_oid *id)
+{
+	return reference_create_oid(ref_out, repo, name, id, 1);
+}
 
 /**
  * Getters
@@ -964,6 +1265,9 @@ const git_oid *git_reference_oid(git_reference *ref)
 	if ((ref->type & GIT_REF_OID) == 0)
 		return NULL;
 
+	if (loose_update(ref) < GIT_SUCCESS)
+		return NULL;
+
 	return &((reference_oid *)ref)->oid;
 }
 
@@ -974,6 +1278,9 @@ const char *git_reference_target(git_reference *ref)
 	if ((ref->type & GIT_REF_SYMBOLIC) == 0)
 		return NULL;
 
+	if (loose_update(ref) < GIT_SUCCESS)
+		return NULL;
+
 	return ((reference_symbolic *)ref)->target;
 }
 
@@ -1012,6 +1319,13 @@ int git_reference_set_oid(git_reference *ref, const git_oid *id)
 
 	ref_oid = (reference_oid *)ref;
 
+	assert(ref->owner);
+
+	/* Don't let the user create references to OIDs that
+	 * don't exist in the ODB */
+	if (!git_odb_exists(git_repository_database(ref->owner), id))
+		return GIT_ENOTFOUND;
+
 	/* duplicate the reference;
 	 * this copy will stay on the packfile cache */
 	if (ref->type & GIT_REF_PACKED) {
@@ -1129,125 +1443,14 @@ cleanup:
 	return error;
 }
 
-/*
- * Rename a reference
- *
- * If the reference is packed, we need to rewrite the
- * packfile to remove the reference from it and create
- * the reference back as a loose one.
- *
- * If the reference is loose, we just rename it on
- * the filesystem.
- *
- * We also need to re-insert the reference on its corresponding
- * in-memory cache, since the caches are indexed by refname.
- */
 int git_reference_rename(git_reference *ref, const char *new_name)
 {
-	int error;
-	char *old_name;
-	char old_path[GIT_PATH_MAX], new_path[GIT_PATH_MAX], normalized_name[MAX_GITDIR_TREE_STRUCTURE_PATH_LENGTH];
-	git_reference *looked_up_ref;
-
-	assert(ref);
-
-	/* Ensure the name is valid */
-	error = normalize_name(normalized_name, new_name, ref->type & GIT_REF_OID);
-	if (error < GIT_SUCCESS)
-		return error;
-
-	/* Ensure we're not going to overwrite an existing reference */
-	error = git_reference_lookup(&looked_up_ref, ref->owner, new_name);
-	if (error == GIT_SUCCESS)
-		return GIT_EINVALIDREFNAME;
-
-	if (error != GIT_ENOTFOUND)
-		return error;
-
-
-	old_name = ref->name;
-	ref->name = git__strdup(new_name);
-
-	if (ref->name == NULL) {
-		ref->name = old_name;
-		return GIT_ENOMEM;
-	}
-
-	if (ref->type & GIT_REF_PACKED) {
-		/* write the packfile to disk; note
-		 * that the state of the in-memory cache is not
-		 * consistent, because the reference is indexed
-		 * by its old name but it already has the new one.
-		 * This doesn't affect writing, though, and allows
-		 * us to rollback if writing fails
-		 */
-
-		ref->type &= ~GIT_REF_PACKED;
-
-		/* Create the loose ref under its new name */
-		error = loose_write(ref);
-		if (error < GIT_SUCCESS) {
-			ref->type |= GIT_REF_PACKED;
-			goto cleanup;
-		}
-
-		/* Remove from the packfile cache in order to avoid packing it back
-		 * Note : we do not rely on git_reference_delete() because this would
-		 * invalidate the reference.
-		 */
-		git_hashtable_remove(ref->owner->references.packfile, old_name);
-
-		/* Recreate the packed-refs file without the reference */
-		error = packed_write(ref->owner);
-		if (error < GIT_SUCCESS)
-			goto rename_loose_to_old_name;
-
-	} else {
-		git__joinpath(old_path, ref->owner->path_repository, old_name);
-		git__joinpath(new_path, ref->owner->path_repository, ref->name);
-
-		error = gitfo_mv_force(old_path, new_path);
-		if (error < GIT_SUCCESS)
-			goto cleanup;
-
-		/* Once succesfully renamed, remove from the cache the reference known by its old name*/
-		git_hashtable_remove(ref->owner->references.loose_cache, old_name);
-	}
-
-	/* Store the renamed reference into the loose ref cache */
-	error = git_hashtable_insert(ref->owner->references.loose_cache, ref->name, ref);
-
-	free(old_name);
-	return error;
-
-cleanup:
-	/* restore the old name if this failed */
-	free(ref->name);
-	ref->name = old_name;
-	return error;
-
-rename_loose_to_old_name:
-	/* If we hit this point. Something *bad* happened! Think "Ghostbusters
-	 * crossing the streams" definition of bad.
-	 * Either the packed-refs has been correctly generated and something else
-	 * has gone wrong, or the writing of the new packed-refs has failed, and
-	 * we're stuck with the old one. As a loose ref always takes priority over
-	 * a packed ref, we'll eventually try and rename the generated loose ref to
-	 * its former name. It even that fails, well... we might have lost the reference
-	 * for good. :-/
-	*/
-
-	git__joinpath(old_path, ref->owner->path_repository, ref->name);
-	git__joinpath(new_path, ref->owner->path_repository, old_name);
-
-	/* No error checking. We'll return the initial error */
-	gitfo_mv_force(old_path, new_path);
-
-	/* restore the old name */
-	free(ref->name);
-	ref->name = old_name;
+	return reference_rename(ref, new_name, 0);
+}
 
-	return error;
+int git_reference_rename_f(git_reference *ref, const char *new_name)
+{
+	return reference_rename(ref, new_name, 1);
 }
 
 int git_reference_resolve(git_reference **resolved_ref, git_reference *ref)
@@ -1257,6 +1460,9 @@ int git_reference_resolve(git_reference **resolved_ref, git_reference *ref)
 
 	assert(resolved_ref && ref);
 	*resolved_ref = NULL;
+
+	if ((error = loose_update(ref)) < GIT_SUCCESS)
+		return error;
 	
 	repo = ref->owner;
 
@@ -1292,6 +1498,69 @@ int git_reference_packall(git_repository *repo)
 	return packed_write(repo);
 }
 
+int git_reference_listcb(git_repository *repo, unsigned int list_flags, int (*callback)(const char *, void *), void *payload)
+{
+	int error;
+	struct dirent_list_data data;
+	char refs_path[GIT_PATH_MAX];
+
+	/* list all the packed references first */
+	if (list_flags & GIT_REF_PACKED) {
+		const char *ref_name;
+		void *_unused;
+
+		if ((error = packed_load(repo)) < GIT_SUCCESS)
+			return error;
+
+		GIT_HASHTABLE_FOREACH(repo->references.packfile, ref_name, _unused,
+			if ((error = callback(ref_name, payload)) < GIT_SUCCESS)
+				return error;
+		);
+	}
+
+	/* now list the loose references, trying not to
+	 * duplicate the ref names already in the packed-refs file */
+
+	data.repo_path_len = strlen(repo->path_repository);
+	data.list_flags = list_flags;
+	data.repo = repo;
+	data.callback = callback;
+	data.callback_payload = payload;
+
+
+	git__joinpath(refs_path, repo->path_repository, GIT_REFS_DIR);
+	return gitfo_dirent(refs_path, GIT_PATH_MAX, _dirent_loose_listall, &data);
+}
+
+int cb__reflist_add(const char *ref, void *data)
+{
+	return git_vector_insert((git_vector *)data, git__strdup(ref));
+}
+
+int git_reference_listall(git_strarray *array, git_repository *repo, unsigned int list_flags)
+{
+	int error;
+	git_vector ref_list;
+
+	assert(array && repo);
+
+	array->strings = NULL;
+	array->count = 0;
+
+	if (git_vector_init(&ref_list, 8, NULL) < GIT_SUCCESS)
+		return GIT_ENOMEM;
+
+	error = git_reference_listcb(repo, list_flags, &cb__reflist_add, (void *)&ref_list);
+
+	if (error < GIT_SUCCESS) {
+		git_vector_free(&ref_list);
+		return error;
+	}
+
+	array->strings = (char **)ref_list.contents;
+	array->count = ref_list.length;
+	return GIT_SUCCESS;
+}
 
 
 
@@ -1411,8 +1680,9 @@ static int normalize_name(char *buffer_out, const char *name, int is_oid_ref)
 		*buffer_out++ = *current++;
 	}
 
-	/* Object id refname have to contain at least one slash */
-	if (is_oid_ref && !contains_a_slash)
+	/* Object id refname have to contain at least one slash, except
+	 * for HEAD in a detached state */
+	if (is_oid_ref && !contains_a_slash && strcmp(name, GIT_HEAD_FILE))
 				return GIT_EINVALIDREFNAME;
 
 	/* A refname can not end with ".lock" */
@@ -1421,9 +1691,13 @@ static int normalize_name(char *buffer_out, const char *name, int is_oid_ref)
 
 	*buffer_out = '\0';
 
-	/* For object id references, name has to start with refs/(heads|tags|remotes) */
-	if (is_oid_ref && !(!git__prefixcmp(buffer_out_start, GIT_REFS_HEADS_DIR) ||
-			!git__prefixcmp(buffer_out_start, GIT_REFS_TAGS_DIR) || !git__prefixcmp(buffer_out_start, GIT_REFS_REMOTES_DIR)))
+	/*
+	 * For object id references, name has to start with refs/. Again,
+	 * we need to allow HEAD to be in a detached state.
+	 */
+	if (is_oid_ref &&
+		!(git__prefixcmp(buffer_out_start, GIT_REFS_DIR) ||
+		  strcmp(buffer_out_start, GIT_HEAD_FILE)))
 		return GIT_EINVALIDREFNAME;
 
 	return error;
diff --git a/src/refs.h b/src/refs.h
index a542ac0f2..bebb1b97d 100644
--- a/src/refs.h
+++ b/src/refs.h
@@ -23,11 +23,13 @@ struct git_reference {
 	git_repository *owner;
 	char *name;
 	unsigned int type;
+	time_t mtime;
 };
 
 typedef struct {
 	git_hashtable *packfile;
 	git_hashtable *loose_cache;
+	time_t packfile_time;
 } git_refcache;
 
 
diff --git a/src/repository.c b/src/repository.c
index f2cb985af..91b95a881 100644
--- a/src/repository.c
+++ b/src/repository.c
@@ -40,30 +40,12 @@
 
 #define GIT_BRANCH_MASTER "master"
 
-static const int OBJECT_TABLE_SIZE = 32;
-
 typedef struct {
 	char *path_repository;
 	unsigned is_bare:1, has_been_reinit:1;
 } repo_init;
 
 /*
- * Hash table methods
- *
- * Callbacks for the ODB cache, implemented
- * as a hash table
- */
-uint32_t object_table_hash(const void *key, int hash_id)
-{
-	uint32_t r;
-	git_oid *id;
-
-	id = (git_oid *)key;
-	memcpy(&r, id->id + (hash_id * sizeof(uint32_t)), sizeof(r));
-	return r;
-}
-
-/*
  * Git repository open methods
  *
  * Open a repository object from its path
@@ -84,7 +66,7 @@ static int assign_repository_dirs(
 	if (git_dir == NULL)
 		return GIT_ENOTFOUND;
 
-	error = gitfo_prettify_dir_path(path_aux, git_dir);
+	error = gitfo_prettify_dir_path(path_aux, sizeof(path_aux), git_dir);
 	if (error < GIT_SUCCESS)
 		return error;
 
@@ -99,7 +81,7 @@ static int assign_repository_dirs(
 	if (git_object_directory == NULL)
 		git__joinpath(path_aux, repo->path_repository, GIT_OBJECTS_DIR);
 	else {
-		error = gitfo_prettify_dir_path(path_aux, git_object_directory);
+		error = gitfo_prettify_dir_path(path_aux, sizeof(path_aux), git_object_directory);
 		if (error < GIT_SUCCESS)
 			return error;
 	}
@@ -113,7 +95,7 @@ static int assign_repository_dirs(
 	if (git_work_tree == NULL)
 		repo->is_bare = 1;
 	else {
-		error = gitfo_prettify_dir_path(path_aux, git_work_tree);
+		error = gitfo_prettify_dir_path(path_aux, sizeof(path_aux), git_work_tree);
 		if (error < GIT_SUCCESS)
 			return error;
 
@@ -126,7 +108,7 @@ static int assign_repository_dirs(
 		if (git_index_file == NULL)
 			git__joinpath(path_aux, repo->path_repository, GIT_INDEX_FILE);
 		else {
-			error = gitfo_prettify_file_path(path_aux, git_index_file);
+			error = gitfo_prettify_file_path(path_aux, sizeof(path_aux), git_index_file);
 			if (error < GIT_SUCCESS)
 				return error;
 		}
@@ -186,30 +168,13 @@ static git_repository *repository_alloc()
 
 	memset(repo, 0x0, sizeof(git_repository));
 
-	repo->objects = git_hashtable_alloc(
-			OBJECT_TABLE_SIZE, 
-			object_table_hash,
-			(git_hash_keyeq_ptr)git_oid_cmp);
-
-	if (repo->objects == NULL) { 
-		free(repo);
-		return NULL;
-	}
+	git_cache_init(&repo->objects, GIT_DEFAULT_CACHE_SIZE, &git_object__free);
 
 	if (git_repository__refcache_init(&repo->references) < GIT_SUCCESS) {
-		git_hashtable_free(repo->objects);
 		free(repo);
 		return NULL;
 	}
 
-	if (git_vector_init(&repo->memory_objects, 16, NULL) < GIT_SUCCESS) {
-		git_hashtable_free(repo->objects);
-		git_repository__refcache_free(&repo->references);
-		free(repo);
-		return NULL;
-	}
-
-	repo->gc_enabled = 1;
 	return repo;
 }
 
@@ -331,20 +296,19 @@ cleanup:
 	return error;
 }
 
-static void repository_free(git_repository *repo)
+void git_repository_free(git_repository *repo)
 {
-	assert(repo);
+	if (repo == NULL)
+		return;
+
+	git_cache_free(&repo->objects);
+	git_repository__refcache_free(&repo->references);
 
 	free(repo->path_workdir);
 	free(repo->path_index);
 	free(repo->path_repository);
 	free(repo->path_odb);
 
-	git_hashtable_free(repo->objects);
-	git_vector_free(&repo->memory_objects);
-
-	git_repository__refcache_free(&repo->references);
-
 	if (repo->db != NULL)
 		git_odb_close(repo->db);
 
@@ -354,53 +318,6 @@ static void repository_free(git_repository *repo)
 	free(repo);
 }
 
-void git_repository_free__no_gc(git_repository *repo)
-{
-	git_object *object;
-	const void *_unused;
-	unsigned int i;
-
-	if (repo == NULL)
-		return;
-
-	GIT_HASHTABLE_FOREACH(repo->objects, _unused, object,
-		object->repo = NULL;
-		object->refcount = 0;
-	);
-
-	for (i = 0; i < repo->memory_objects.length; ++i) {
-		object = git_vector_get(&repo->memory_objects, i);
-		object->repo = NULL;
-		object->refcount = 0;
-	}
-
-	repository_free(repo);
-}
-
-void git_repository_free(git_repository *repo)
-{
-	git_object *object;
-	const void *_unused;
-	unsigned int i;
-
-	if (repo == NULL)
-		return;
-
-	repo->gc_enabled = 0;
-
-	/* force free all the objects */
-	GIT_HASHTABLE_FOREACH(repo->objects, _unused, object,
-		git_object__free(object);
-	);
-
-	for (i = 0; i < repo->memory_objects.length; ++i) {
-		object = git_vector_get(&repo->memory_objects, i);
-		git_object__free(object);
-	}
-
-	repository_free(repo);
-}
-
 int git_repository_index(git_index **index_out, git_repository *repo)
 {
 	int error;
@@ -486,7 +403,7 @@ static int repo_init_find_dir(repo_init *results, const char* path)
 	char temp_path[GIT_PATH_MAX];
 	int error = GIT_SUCCESS;
 
-	error = gitfo_prettify_dir_path(temp_path, path);
+	error = gitfo_prettify_dir_path(temp_path, sizeof(temp_path), path);
 	if (error < GIT_SUCCESS)
 		return error;
 
diff --git a/src/repository.h b/src/repository.h
index 5318ed45c..fef1c7da0 100644
--- a/src/repository.h
+++ b/src/repository.h
@@ -9,6 +9,7 @@
 
 #include "hashtable.h"
 #include "index.h"
+#include "cache.h"
 #include "refs.h"
 
 #define DOT_GIT ".git"
@@ -16,28 +17,17 @@
 #define GIT_OBJECTS_DIR "objects/"
 #define GIT_INDEX_FILE "index"
 
-typedef struct {
-	git_rawobj raw;
-	void *write_ptr;
-	size_t written_bytes;
-	int open:1;
-} git_odb_source;
-
 struct git_object {
-	git_oid id;
+	git_cached_obj cached;
 	git_repository *repo;
-	git_odb_source source;
-	unsigned short refcount;
-	unsigned char in_memory, modified;
+	git_otype type;
 };
 
 struct git_repository {
 	git_odb *db;
 	git_index *index;
 
-	git_hashtable *objects;
-	git_vector memory_objects;
-
+	git_cache objects;
 	git_refcache references;
 
 	char *path_repository;
@@ -45,35 +35,15 @@ struct git_repository {
 	char *path_odb;
 	char *path_workdir;
 
-	unsigned is_bare:1, gc_enabled:1;
+	unsigned is_bare:1;
+	unsigned int lru_counter;
 };
 
-int git_object__source_open(git_object *object);
-void git_object__source_close(git_object *object);
-
 /* fully free the object; internal method, do not
  * export */
-void git_object__free(git_object *object);
-
-int git__source_printf(git_odb_source *source, const char *format, ...);
-int git__source_write(git_odb_source *source, const void *bytes, size_t len);
+void git_object__free(void *object);
 
 int git__parse_oid(git_oid *oid, char **buffer_out, const char *buffer_end, const char *header);
-int git__write_oid(git_odb_source *src, const char *header, const git_oid *oid);
-
-#define GIT_OBJECT_INCREF(repo, ob) git_object__incref((repo), (git_object *)(ob))
-#define GIT_OBJECT_DECREF(repo, ob) git_object__decref((repo), (git_object *)(ob)) 
-
-GIT_INLINE(void) git_object__incref(git_repository *repo, struct git_object *object)
-{
-	if (repo && repo->gc_enabled && object)
-		object->refcount++;
-}
-
-GIT_INLINE(void) git_object__decref(git_repository *repo, struct git_object *object)
-{
-	if (repo && repo->gc_enabled && object)
-		git_object_close(object);
-}
+int git__write_oid(git_odb_stream *src, const char *header, const git_oid *oid);
 
 #endif
diff --git a/src/revwalk.c b/src/revwalk.c
index a1cd0ebb7..73bb060f5 100644
--- a/src/revwalk.c
+++ b/src/revwalk.c
@@ -25,437 +25,553 @@
 
 #include "common.h"
 #include "commit.h"
-#include "revwalk.h"
+#include "odb.h"
 #include "hashtable.h"
+#include "pqueue.h"
 
-uint32_t git_revwalk__commit_hash(const void *key, int hash_id)
-{
-	uint32_t r;
-	git_commit *commit;
+#include "git2/revwalk.h"
 
-	commit = (git_commit *)key;
-	memcpy(&r, commit->object.id.id + (hash_id * sizeof(uint32_t)), sizeof(r));
-	return r;
-}
+typedef struct commit_object {
+	git_oid oid;
+	uint32_t time;
+	unsigned int seen:1,
+			 uninteresting:1,
+			 topo_delay:1,
+			 parsed:1;
+
+	unsigned short in_degree;
+	unsigned short out_degree;
+
+	struct commit_object **parents;
+} commit_object;
+
+typedef struct commit_list {
+	commit_object *item;
+	struct commit_list *next;
+} commit_list;
 
-int git_revwalk__commit_keycmp(const void *key_a, const void *key_b)
+struct git_revwalk {
+	git_repository *repo;
+
+	git_hashtable *commits;
+
+	commit_list *iterator_topo;
+	commit_list *iterator_rand;
+	commit_list *iterator_reverse;
+	git_pqueue iterator_time;
+
+	int (*get_next)(commit_object **, git_revwalk *);
+	int (*enqueue)(git_revwalk *, commit_object *);
+
+	git_vector memory_alloc;
+	size_t chunk_size;
+
+	unsigned walking:1;
+	unsigned int sorting;
+};
+
+commit_list *commit_list_insert(commit_object *item, commit_list **list_p)
 {
-	git_commit *a = (git_commit *)key_a;
-	git_commit *b = (git_commit *)key_b;
-	return git_oid_cmp(&a->object.id, &b->object.id);
+	commit_list *new_list = git__malloc(sizeof(commit_list));
+	new_list->item = item;
+	new_list->next = *list_p;
+	*list_p = new_list;
+	return new_list;
 }
 
-int git_revwalk_new(git_revwalk **revwalk_out, git_repository *repo)
+void commit_list_free(commit_list **list_p)
 {
-	git_revwalk *walk;
+	commit_list *list = *list_p;
 
-	walk = git__malloc(sizeof(git_revwalk));
-	if (walk == NULL)
-		return GIT_ENOMEM;
+	while (list) {
+		commit_list *temp = list;
+		list = temp->next;
+		free(temp);
+	}
 
-	memset(walk, 0x0, sizeof(git_revwalk));
+	*list_p = NULL;
+}
 
-	walk->commits = git_hashtable_alloc(64,
-			git_revwalk__commit_hash,
-			git_revwalk__commit_keycmp);
+commit_object *commit_list_pop(commit_list **stack)
+{
+	commit_list *top = *stack;
+	commit_object *item = top ? top->item : NULL;
 
-	if (walk->commits == NULL) {
-		free(walk);
-		return GIT_ENOMEM;
+	if (top) {
+		*stack = top->next;
+		free(top);
 	}
+	return item;
+}
 
-	walk->repo = repo;
+static int commit_time_cmp(void *a, void *b)
+{
+	commit_object *commit_a = (commit_object *)a;
+	commit_object *commit_b = (commit_object *)b;
 
-	*revwalk_out = walk;
-	return GIT_SUCCESS;
+	return (commit_a->time < commit_b->time);
 }
 
-void git_revwalk_free(git_revwalk *walk)
+static uint32_t object_table_hash(const void *key, int hash_id)
 {
-	if (walk == NULL)
-		return;
+	uint32_t r;
+	git_oid *id;
 
-	git_revwalk_reset(walk);
-	git_hashtable_free(walk->commits);
-	free(walk);
+	id = (git_oid *)key;
+	memcpy(&r, id->id + (hash_id * sizeof(uint32_t)), sizeof(r));
+	return r;
 }
 
-git_repository *git_revwalk_repository(git_revwalk *walk)
+#define COMMITS_PER_CHUNK 128
+#define CHUNK_STEP 64
+#define PARENTS_PER_COMMIT ((CHUNK_STEP - sizeof(commit_object)) / sizeof(commit_object *))
+
+static int alloc_chunk(git_revwalk *walk)
 {
-	assert(walk);
-	return walk->repo;
+	void *chunk;
+
+	chunk = git__calloc(COMMITS_PER_CHUNK, CHUNK_STEP);
+	if (chunk == NULL)
+		return GIT_ENOMEM;
+
+	walk->chunk_size = 0;
+	return git_vector_insert(&walk->memory_alloc, chunk);
 }
 
-int git_revwalk_sorting(git_revwalk *walk, unsigned int sort_mode)
+static commit_object *alloc_commit(git_revwalk *walk)
 {
-	assert(walk);
+	unsigned char *chunk;
 
-	if (walk->walking)
-		return GIT_EBUSY;
+	if (walk->chunk_size == COMMITS_PER_CHUNK)
+		alloc_chunk(walk);
 
-	walk->sorting = sort_mode;
-	git_revwalk_reset(walk);
-	return GIT_SUCCESS;
+	chunk = git_vector_get(&walk->memory_alloc, walk->memory_alloc.length - 1);
+	chunk += (walk->chunk_size * CHUNK_STEP);
+	walk->chunk_size++;
+
+	return (commit_object *)chunk;
 }
 
-static git_revwalk_commit *commit_to_walkcommit(git_revwalk *walk, git_commit *commit_object)
+static commit_object **alloc_parents(commit_object *commit, size_t n_parents)
 {
-	git_revwalk_commit *commit;
+	if (n_parents <= PARENTS_PER_COMMIT)
+		return (commit_object **)((unsigned char *)commit + sizeof(commit_object));
 
-	commit = (git_revwalk_commit *)git_hashtable_lookup(walk->commits, commit_object);
+	return git__malloc(n_parents * sizeof(commit_object *));
+}
 
-	if (commit != NULL)
+
+static commit_object *commit_lookup(git_revwalk *walk, const git_oid *oid)
+{
+	commit_object *commit;
+
+	if ((commit = git_hashtable_lookup(walk->commits, oid)) != NULL)
 		return commit;
 
-	commit = git__malloc(sizeof(git_revwalk_commit));
+	commit = alloc_commit(walk);
 	if (commit == NULL)
 		return NULL;
 
-	memset(commit, 0x0, sizeof(git_revwalk_commit));
-
-	commit->commit_object = commit_object;
-	GIT_OBJECT_INCREF(walk->repo, commit_object);
+	git_oid_cpy(&commit->oid, oid);
 
-	git_hashtable_insert(walk->commits, commit_object, commit);
+	if (git_hashtable_insert(walk->commits, &commit->oid, commit) < GIT_SUCCESS) {
+		free(commit);
+		return NULL;
+	}
 
 	return commit;
 }
 
-static git_revwalk_commit *insert_commit(git_revwalk *walk, git_commit *commit_object)
+static int commit_quick_parse(git_revwalk *walk, commit_object *commit, git_rawobj *raw)
 {
-	git_revwalk_commit *commit;
-	unsigned int i;
+	const int parent_len = STRLEN("parent ") + GIT_OID_HEXSZ + 1;
 
-	assert(walk && commit_object);
+	unsigned char *buffer = raw->data;
+	unsigned char *buffer_end = buffer + raw->len;
+	unsigned char *parents_start;
 
-	if (commit_object->object.repo != walk->repo || walk->walking)
-		return NULL;
+	int i, parents = 0;
 
-	commit = commit_to_walkcommit(walk, commit_object);
-	if (commit == NULL)
-		return NULL;
+	buffer += STRLEN("tree ") + GIT_OID_HEXSZ + 1;
 
-	if (commit->seen)
-		return commit;
+	parents_start = buffer;
+	while (buffer + parent_len < buffer_end && memcmp(buffer, "parent ", STRLEN("parent ")) == 0) {
+		parents++;
+		buffer += parent_len;
+	}
 
-	commit->seen = 1;
+	commit->parents = alloc_parents(commit, parents);
+	if (commit->parents == NULL)
+		return GIT_ENOMEM;
 
-	for (i = 0; i < commit->commit_object->parents.length; ++i) {
-		git_commit *parent_object;
-		git_revwalk_commit *parent;
+	buffer = parents_start;
+	for (i = 0; i < parents; ++i) {
+		git_oid oid;
 
-		parent_object = git_vector_get(&commit->commit_object->parents, i);
+		if (git_oid_mkstr(&oid, (char *)buffer + STRLEN("parent ")) < GIT_SUCCESS)
+			return GIT_EOBJCORRUPTED;
 
-		if ((parent = commit_to_walkcommit(walk, parent_object)) == NULL)
-			return NULL;
+		commit->parents[i] = commit_lookup(walk, &oid);
+		if (commit->parents[i] == NULL)
+			return GIT_ENOMEM;
 
-		parent = insert_commit(walk, parent_object);
-		if (parent == NULL)
-			return NULL;
+		buffer += parent_len;
+	}
 
-		parent->in_degree++;
+	commit->out_degree = (unsigned short)parents;
 
-		git_revwalk_list_push_back(&commit->parents, parent);
-	}
+	if ((buffer = memchr(buffer, '\n', buffer_end - buffer)) == NULL)
+		return GIT_EOBJCORRUPTED;
 
-	if (git_revwalk_list_push_back(&walk->iterator, commit))
-		return NULL;
+	buffer = memchr(buffer, '>', buffer_end - buffer);
+	if (buffer == NULL)
+		return GIT_EOBJCORRUPTED;
 
-	return commit;
+	commit->time = strtol((char *)buffer + 2, NULL, 10);
+	if (commit->time == 0)
+		return GIT_EOBJCORRUPTED;
+
+	commit->parsed = 1;
+	return GIT_SUCCESS;
 }
 
-int git_revwalk_push(git_revwalk *walk, git_commit *commit)
+static int commit_parse(git_revwalk *walk, commit_object *commit)
 {
-	assert(walk && commit);
-	return insert_commit(walk, commit) ? GIT_SUCCESS : GIT_ENOMEM;
+	git_odb_object *obj;
+	int error;
+
+	if (commit->parsed)
+		return GIT_SUCCESS;
+
+	if ((error = git_odb_read(&obj, walk->repo->db, &commit->oid)) < GIT_SUCCESS)
+		return error;
+
+	if (obj->raw.type != GIT_OBJ_COMMIT) {
+		git_odb_object_close(obj);
+		return GIT_EOBJTYPE;
+	}
+
+	error = commit_quick_parse(walk, commit, &obj->raw);
+	git_odb_object_close(obj);
+	return error;
 }
 
-static void mark_uninteresting(git_revwalk_commit *commit)
+static void mark_uninteresting(commit_object *commit)
 {
-	git_revwalk_listnode *parent;
-
+	unsigned short i;
 	assert(commit);
 
 	commit->uninteresting = 1;
-	parent = commit->parents.head;
 
-	while (parent) {
-		mark_uninteresting(parent->walk_commit);
-		parent = parent->next;
-	}
+	for (i = 0; i < commit->out_degree; ++i)
+		if (!commit->parents[i]->uninteresting)
+			mark_uninteresting(commit->parents[i]);
 }
 
-int git_revwalk_hide(git_revwalk *walk, git_commit *commit)
+static int process_commit(git_revwalk *walk, commit_object *commit)
 {
-	git_revwalk_commit *hide;
+	int error;
 
-	assert(walk && commit);
-	
-	hide = insert_commit(walk, commit);
-	if (hide == NULL)
-		return GIT_ENOMEM;
+	if (commit->seen)
+		return GIT_SUCCESS;
 
-	mark_uninteresting(hide);
-	return GIT_SUCCESS;
+	commit->seen = 1;
+
+	if ((error = commit_parse(walk, commit)) < GIT_SUCCESS)
+			return error;
+
+	if (commit->uninteresting)
+		mark_uninteresting(commit);
+
+	return walk->enqueue(walk, commit);
 }
 
+static int process_commit_parents(git_revwalk *walk, commit_object *commit)
+{
+	unsigned short i;
+	int error = GIT_SUCCESS;
+
+	for (i = 0; i < commit->out_degree && error == GIT_SUCCESS; ++i) {
+		error = process_commit(walk, commit->parents[i]);
+	}
+
+	return error;
+}
 
-static void prepare_walk(git_revwalk *walk)
+static int push_commit(git_revwalk *walk, const git_oid *oid, int uninteresting)
 {
-	if (walk->sorting & GIT_SORT_TIME)
-		git_revwalk_list_timesort(&walk->iterator);
+	commit_object *commit;
 
-	if (walk->sorting & GIT_SORT_TOPOLOGICAL)
-		git_revwalk_list_toposort(&walk->iterator);
+	commit = commit_lookup(walk, oid);
+	if (commit == NULL)
+		return GIT_ENOTFOUND;
 
-	if (walk->sorting & GIT_SORT_REVERSE)
-		walk->next = &git_revwalk_list_pop_back;
-	else
-		walk->next = &git_revwalk_list_pop_front;
+	commit->uninteresting = uninteresting;
 
-	walk->walking = 1;
+	return process_commit(walk, commit);
 }
 
-int git_revwalk_next(git_commit **commit, git_revwalk *walk)
+int git_revwalk_push(git_revwalk *walk, const git_oid *oid)
 {
-	git_revwalk_commit *next;
+	assert(walk && oid);
+	return push_commit(walk, oid, 0);
+}
 
-	assert(walk && commit);
+int git_revwalk_hide(git_revwalk *walk, const git_oid *oid)
+{
+	assert(walk && oid);
+	return push_commit(walk, oid, 1);
+}
+
+static int revwalk_enqueue_timesort(git_revwalk *walk, commit_object *commit)
+{
+	return git_pqueue_insert(&walk->iterator_time, commit);
+}
+
+static int revwalk_enqueue_unsorted(git_revwalk *walk, commit_object *commit)
+{
+	return commit_list_insert(commit, &walk->iterator_rand) ? GIT_SUCCESS : GIT_ENOMEM;
+}
 
-	if (!walk->walking)
-		prepare_walk(walk);
+static int revwalk_next_timesort(commit_object **object_out, git_revwalk *walk)
+{
+	int error;
+	commit_object *next;
 
-	*commit = NULL;
+	while ((next = git_pqueue_pop(&walk->iterator_time)) != NULL) {
+		if ((error = process_commit_parents(walk, next)) < GIT_SUCCESS)
+			return error;
 
-	while ((next = walk->next(&walk->iterator)) != NULL) {
 		if (!next->uninteresting) {
-			*commit = next->commit_object;
-			GIT_OBJECT_INCREF(walk->repo, *commit);
+			*object_out = next;
 			return GIT_SUCCESS;
 		}
 	}
 
-	/* No commits left to iterate */
-	git_revwalk_reset(walk);
 	return GIT_EREVWALKOVER;
 }
 
-void git_revwalk_reset(git_revwalk *walk)
+static int revwalk_next_unsorted(commit_object **object_out, git_revwalk *walk)
 {
-	const void *_unused;
-	git_revwalk_commit *commit;
+	int error;
+	commit_object *next;
 
-	assert(walk);
+	while ((next = commit_list_pop(&walk->iterator_rand)) != NULL) {
+		if ((error = process_commit_parents(walk, next)) < GIT_SUCCESS)
+			return error;
 
-	GIT_HASHTABLE_FOREACH(walk->commits, _unused, commit, {
-		GIT_OBJECT_DECREF(walk->repo, commit->commit_object);
-		git_revwalk_list_clear(&commit->parents);
-		free(commit);
-	});
+		if (!next->uninteresting) {
+			*object_out = next;
+			return GIT_SUCCESS;
+		}
+	}
 
-	git_hashtable_clear(walk->commits);
-	git_revwalk_list_clear(&walk->iterator);
-	walk->walking = 0;
+	return GIT_EREVWALKOVER;
 }
 
-
-
-
-
-
-int git_revwalk_list_push_back(git_revwalk_list *list, git_revwalk_commit *commit)
+static int revwalk_next_toposort(commit_object **object_out, git_revwalk *walk)
 {
-	git_revwalk_listnode *node = NULL;
+	commit_object *next;
+	unsigned short i;
 
-	node = git__malloc(sizeof(git_revwalk_listnode));
+	for (;;) {
+		next = commit_list_pop(&walk->iterator_topo);
+		if (next == NULL)
+			return GIT_EREVWALKOVER;
 
-	if (node == NULL)
-		return GIT_ENOMEM;
+		if (next->in_degree > 0) {
+			next->topo_delay = 1;
+			continue;
+		}
 
-	node->walk_commit = commit;
-	node->next = NULL;
-	node->prev = list->tail;
+		for (i = 0; i < next->out_degree; ++i) {
+			commit_object *parent = next->parents[i];
 
-	if (list->tail == NULL) {
-		list->head = list->tail = node;
-	} else {
-		list->tail->next = node;
-		list->tail = node;
+			if (--parent->in_degree == 0 && parent->topo_delay) {
+				parent->topo_delay = 0;
+				commit_list_insert(parent, &walk->iterator_topo);
+			}
+		}
+
+		*object_out = next;
+		return GIT_SUCCESS;
 	}
+}
 
-	list->size++;
-	return 0;
+static int revwalk_next_reverse(commit_object **object_out, git_revwalk *walk)
+{
+	*object_out = commit_list_pop(&walk->iterator_reverse);
+	return *object_out ? GIT_SUCCESS : GIT_EREVWALKOVER;
 }
 
-int git_revwalk_list_push_front(git_revwalk_list *list, git_revwalk_commit *commit)
+
+static int prepare_walk(git_revwalk *walk)
 {
-	git_revwalk_listnode *node = NULL;
+	int error;
+	commit_object *next;
 
-	node = git__malloc(sizeof(git_revwalk_listnode));
+	if (walk->sorting & GIT_SORT_TOPOLOGICAL) {
+		unsigned short i;
 
-	if (node == NULL)
-		return GIT_ENOMEM;
+		while ((error = walk->get_next(&next, walk)) == GIT_SUCCESS) {
+			for (i = 0; i < next->out_degree; ++i) {
+				commit_object *parent = next->parents[i];
+				parent->in_degree++;
+			}
 
-	node->walk_commit = commit;
-	node->next = list->head;
-	node->prev = NULL;
+			commit_list_insert(next, &walk->iterator_topo);
+		}
 
-	if (list->head == NULL) {
-		list->head = list->tail = node;
-	} else {
-		list->head->prev = node;
-		list->head = node;
+		if (error != GIT_EREVWALKOVER)
+			return error;
+
+		walk->get_next = &revwalk_next_toposort;
 	}
 
-	list->size++;
-	return 0;
-}
+	if (walk->sorting & GIT_SORT_REVERSE) {
 
+		while ((error = walk->get_next(&next, walk)) == GIT_SUCCESS)
+			commit_list_insert(next, &walk->iterator_reverse);
 
-git_revwalk_commit *git_revwalk_list_pop_back(git_revwalk_list *list)
-{
-	git_revwalk_listnode *node;
-	git_revwalk_commit *commit;
+		if (error != GIT_EREVWALKOVER)
+			return error;
 
-	if (list->tail == NULL)
-		return NULL;
+		walk->get_next = &revwalk_next_reverse;
+	}
+
+	walk->walking = 1;
+	return GIT_SUCCESS;
+}
 
-	node = list->tail;
-	list->tail = list->tail->prev;
-	if (list->tail == NULL)
-		list->head = NULL;
-	else
-		list->tail->next = NULL;
 
-	commit = node->walk_commit;
-	free(node);
 
-	list->size--;
 
-	return commit;
-}
 
-git_revwalk_commit *git_revwalk_list_pop_front(git_revwalk_list *list)
+int git_revwalk_new(git_revwalk **revwalk_out, git_repository *repo)
 {
-	git_revwalk_listnode *node;
-	git_revwalk_commit *commit;
+	git_revwalk *walk;
 
-	if (list->head == NULL)
-		return NULL;
+	walk = git__malloc(sizeof(git_revwalk));
+	if (walk == NULL)
+		return GIT_ENOMEM;
 
-	node = list->head;
-	list->head = list->head->next;
-	if (list->head == NULL)
-		list->tail = NULL;
-	else
-		list->head->prev = NULL;
+	memset(walk, 0x0, sizeof(git_revwalk));
 
-	commit = node->walk_commit;
-	free(node);
+	walk->commits = git_hashtable_alloc(64,
+			object_table_hash,
+			(git_hash_keyeq_ptr)git_oid_cmp);
 
-	list->size--;
+	if (walk->commits == NULL) {
+		free(walk);
+		return GIT_ENOMEM;
+	}
 
-	return commit;
-}
+	git_pqueue_init(&walk->iterator_time, 8, commit_time_cmp);
+	git_vector_init(&walk->memory_alloc, 8, NULL);
+	alloc_chunk(walk);
 
-void git_revwalk_list_clear(git_revwalk_list *list)
-{
-	git_revwalk_listnode *node, *next_node;
+	walk->get_next = &revwalk_next_unsorted;
+	walk->enqueue = &revwalk_enqueue_unsorted;
 
-	node = list->head;
-	while (node) {
-		next_node = node->next;
-		free(node);
-		node = next_node;
-	}
+	walk->repo = repo;
 
-	list->head = list->tail = NULL;
-	list->size = 0;
+	*revwalk_out = walk;
+	return GIT_SUCCESS;
 }
 
-void git_revwalk_list_timesort(git_revwalk_list *list)
+void git_revwalk_free(git_revwalk *walk)
 {
-	git_revwalk_listnode *p, *q, *e;
-	int in_size, p_size, q_size, merge_count, i;
+	unsigned int i;
+	const void *_unused;
+	commit_object *commit;
 
-	if (list->head == NULL)
+	if (walk == NULL)
 		return;
 
-	in_size = 1;
-
-	do {
-		p = list->head;
-		list->tail = NULL;
-		merge_count = 0;
-
-		while (p != NULL) {
-			merge_count++;
-			q = p;
-			p_size = 0;
-			q_size = in_size;
-
-			for (i = 0; i < in_size && q; ++i, q = q->next)
-				p_size++;
+	git_revwalk_reset(walk);
 
-			while (p_size > 0 || (q_size > 0 && q)) {
+	/* if the parent has more than PARENTS_PER_COMMIT parents,
+	 * we had to allocate a separate array for those parents.
+	 * make sure it's being free'd */
+	GIT_HASHTABLE_FOREACH(walk->commits, _unused, commit, {
+		if (commit->out_degree > PARENTS_PER_COMMIT)
+			free(commit->parents);
+	});
 
-				if (p_size == 0)
-					e = q, q = q->next, q_size--;
+	git_hashtable_free(walk->commits);
+	git_pqueue_free(&walk->iterator_time);
 
-				else if (q_size == 0 || q == NULL ||
-						p->walk_commit->commit_object->committer->when.time >= 
-						q->walk_commit->commit_object->committer->when.time)
-					e = p, p = p->next, p_size--;
+	for (i = 0; i < walk->memory_alloc.length; ++i)
+		free(git_vector_get(&walk->memory_alloc, i));
 
-				else
-					e = q, q = q->next, q_size--;
+	git_vector_free(&walk->memory_alloc);
+	free(walk);
+}
 
-				if (list->tail != NULL)
-					list->tail->next = e;
-				else
-					list->head = e;
+git_repository *git_revwalk_repository(git_revwalk *walk)
+{
+	assert(walk);
+	return walk->repo;
+}
 
-				e->prev = list->tail;
-				list->tail = e;
-			}
+void git_revwalk_sorting(git_revwalk *walk, unsigned int sort_mode)
+{
+	assert(walk);
 
-			p = q;
-		}
+	if (walk->walking)
+		git_revwalk_reset(walk);
 
-		list->tail->next = NULL;
-		in_size *= 2;
+	walk->sorting = sort_mode;
 
-	} while (merge_count > 1);
+	if (walk->sorting & GIT_SORT_TIME) {
+		walk->get_next = &revwalk_next_timesort;
+		walk->enqueue = &revwalk_enqueue_timesort;
+	} else {
+		walk->get_next = &revwalk_next_unsorted;
+		walk->enqueue = &revwalk_enqueue_unsorted;
+	}
 }
 
-void git_revwalk_list_toposort(git_revwalk_list *list)
+int git_revwalk_next(git_oid *oid, git_revwalk *walk)
 {
-	git_revwalk_commit *commit;
-	git_revwalk_list topo;
-	memset(&topo, 0x0, sizeof(git_revwalk_list));
+	int error;
+	commit_object *next;
 
-	while ((commit = git_revwalk_list_pop_back(list)) != NULL) {
-		git_revwalk_listnode *p;
+	assert(walk && oid);
 
-		if (commit->in_degree > 0) {
-			commit->topo_delay = 1;
-			continue;
-		}
+	if (!walk->walking) {
+		if ((error = prepare_walk(walk)) < GIT_SUCCESS)
+			return error;
+	}
 
-		for (p = commit->parents.head; p != NULL; p = p->next) {
-			p->walk_commit->in_degree--;
+	error = walk->get_next(&next, walk);
+	if (error < GIT_SUCCESS) {
+		if (error == GIT_EREVWALKOVER)
+			git_revwalk_reset(walk);
+		return error;
+	}
 
-			if (p->walk_commit->in_degree == 0 && p->walk_commit->topo_delay) {
-				p->walk_commit->topo_delay = 0;
-				git_revwalk_list_push_back(list, p->walk_commit);
-			}
-		}
+	git_oid_cpy(oid, &next->oid);
+	return GIT_SUCCESS;
+}
 
-		git_revwalk_list_push_back(&topo, commit);
-	}
+void git_revwalk_reset(git_revwalk *walk)
+{
+	const void *_unused;
+	commit_object *commit;
+
+	assert(walk);
+
+	GIT_HASHTABLE_FOREACH(walk->commits, _unused, commit,
+		commit->seen = 0;
+		commit->in_degree = 0;
+		commit->topo_delay = 0;
+	);
 
-	list->head = topo.head;
-	list->tail = topo.tail;
-	list->size = topo.size;
+	git_pqueue_clear(&walk->iterator_time);
+	commit_list_free(&walk->iterator_topo);
+	commit_list_free(&walk->iterator_rand);
+	commit_list_free(&walk->iterator_reverse);
+	walk->walking = 0;
 }
 
diff --git a/src/revwalk.h b/src/revwalk.h
deleted file mode 100644
index 7b69ccd63..000000000
--- a/src/revwalk.h
+++ /dev/null
@@ -1,67 +0,0 @@
-#ifndef INCLUDE_revwalk_h__
-#define INCLUDE_revwalk_h__
-
-#include "git2/common.h"
-#include "git2/revwalk.h"
-
-#include "commit.h"
-#include "repository.h"
-#include "hashtable.h"
-
-struct git_revwalk_commit;
-
-typedef struct git_revwalk_listnode {
-	struct git_revwalk_commit *walk_commit;
-	struct git_revwalk_listnode *next;
-	struct git_revwalk_listnode *prev;
-} git_revwalk_listnode;
-
-typedef struct git_revwalk_list {
-	struct git_revwalk_listnode *head;
-	struct git_revwalk_listnode *tail;
-	size_t size;
-} git_revwalk_list;
-
-
-struct git_revwalk_commit {
-
-	git_commit *commit_object;
-	git_revwalk_list parents;
-
-	unsigned short in_degree;
-	unsigned seen:1,
-			 uninteresting:1,
-			 topo_delay:1,
-			 flags:25;
-};
-
-typedef struct git_revwalk_commit git_revwalk_commit;
-
-struct git_revwalk {
-	git_repository *repo;
-
-	git_hashtable *commits;
-	git_revwalk_list iterator;
-
-	git_revwalk_commit *(*next)(git_revwalk_list *);
-
-	unsigned walking:1;
-	unsigned int sorting;
-};
-
-
-void git_revwalk__prepare_walk(git_revwalk *walk);
-int git_revwalk__enroot(git_revwalk *walk, git_commit *commit);
-
-int git_revwalk_list_push_back(git_revwalk_list *list, git_revwalk_commit *commit);
-int git_revwalk_list_push_front(git_revwalk_list *list, git_revwalk_commit *obj);
-
-git_revwalk_commit *git_revwalk_list_pop_back(git_revwalk_list *list);
-git_revwalk_commit *git_revwalk_list_pop_front(git_revwalk_list *list);
-
-void git_revwalk_list_clear(git_revwalk_list *list);
-
-void git_revwalk_list_timesort(git_revwalk_list *list);
-void git_revwalk_list_toposort(git_revwalk_list *list);
-
-#endif /* INCLUDE_revwalk_h__ */
diff --git a/src/signature.c b/src/signature.c
index 5c9f15973..412637600 100644
--- a/src/signature.c
+++ b/src/signature.c
@@ -38,7 +38,7 @@ void git_signature_free(git_signature *sig)
 	free(sig);
 }
 
-git_signature *git_signature_new(const char *name, const char *email, time_t time, int offset)
+git_signature *git_signature_new(const char *name, const char *email, git_time_t time, int offset)
 {
 	git_signature *p = NULL;
 
@@ -46,13 +46,7 @@ git_signature *git_signature_new(const char *name, const char *email, time_t tim
 		goto cleanup;
 
 	p->name = git__strdup(name);
-	if (p->name == NULL)
-		goto cleanup;
-
 	p->email = git__strdup(email);
-	if (p->email == NULL)
-		goto cleanup;
-
 	p->when.time = time;
 	p->when.offset = offset;
 
@@ -179,10 +173,12 @@ int git_signature__parse(git_signature *sig, char **buffer_out,
 	return GIT_SUCCESS;
 }
 
-int git_signature__write(git_odb_source *src, const char *header, const git_signature *sig)
+int git_signature__write(char **signature, const char *header, const git_signature *sig)
 {
-	char sign;
 	int offset, hours, mins;
+	char sig_buffer[2048];
+	int sig_buffer_len;
+	char sign;
 
 	offset = sig->when.offset;
 	sign = (sig->when.offset < 0) ? '-' : '+';
@@ -193,7 +189,16 @@ int git_signature__write(git_odb_source *src, const char *header, const git_sign
 	hours = offset / 60;
 	mins = offset % 60;
 
-	return git__source_printf(src, "%s %s <%s> %u %c%02d%02d\n", header, sig->name, sig->email, (unsigned)sig->when.time, sign, hours, mins);
+	sig_buffer_len = snprintf(sig_buffer, sizeof(sig_buffer),
+			"%s %s <%s> %u %c%02d%02d\n",
+			header, sig->name, sig->email,
+			(unsigned)sig->when.time, sign, hours, mins);
+
+	if (sig_buffer_len < 0 || (size_t)sig_buffer_len > sizeof(sig_buffer))
+		return GIT_ENOMEM;
+
+	*signature = git__strdup(sig_buffer);
+	return sig_buffer_len;
 }
 
 
diff --git a/src/signature.h b/src/signature.h
index ee212c2dc..3534cb21f 100644
--- a/src/signature.h
+++ b/src/signature.h
@@ -7,6 +7,6 @@
 #include <time.h>
 
 int git_signature__parse(git_signature *sig, char **buffer_out, const char *buffer_end, const char *header);
-int git_signature__write(git_odb_source *src, const char *header, const git_signature *sig);
+int git_signature__write(char **signature, const char *header, const git_signature *sig);
 
 #endif
diff --git a/src/tag.c b/src/tag.c
index 1ac2067c2..7baababbf 100644
--- a/src/tag.c
+++ b/src/tag.c
@@ -27,7 +27,6 @@
 #include "commit.h"
 #include "tag.h"
 #include "signature.h"
-#include "revwalk.h"
 #include "git2/object.h"
 #include "git2/repository.h"
 #include "git2/signature.h"
@@ -35,7 +34,6 @@
 void git_tag__free(git_tag *tag)
 {
 	git_signature_free(tag->tagger);
-	GIT_OBJECT_DECREF(tag->object.repo, tag->target);
 	free(tag->message);
 	free(tag->tag_name);
 	free(tag);
@@ -46,23 +44,16 @@ const git_oid *git_tag_id(git_tag *c)
 	return git_object_id((git_object *)c);
 }
 
-const git_object *git_tag_target(git_tag *t)
+int git_tag_target(git_object **target, git_tag *t)
 {
 	assert(t);
-	GIT_OBJECT_INCREF(t->object.repo, t->target);
-	return t->target;
+	return git_object_lookup(target, t->object.repo, &t->target, t->type);
 }
 
-void git_tag_set_target(git_tag *tag, git_object *target)
+const git_oid *git_tag_target_oid(git_tag *t)
 {
-	assert(tag && target);
-
-	GIT_OBJECT_DECREF(tag->object.repo, tag->target);
-	GIT_OBJECT_INCREF(tag->object.repo, target);
-
-	tag->object.modified = 1;
-	tag->target = target;
-	tag->type = git_object_type(target);
+	assert(t);
+	return &t->target;
 }
 
 git_otype git_tag_type(git_tag *t)
@@ -77,63 +68,28 @@ const char *git_tag_name(git_tag *t)
 	return t->tag_name;
 }
 
-void git_tag_set_name(git_tag *tag, const char *name)
-{
-	assert(tag && name);
-
-	/* TODO: sanity check? no newlines in message */
-	tag->object.modified = 1;
-
-	if (tag->tag_name)
-		free(tag->tag_name);
-
-	tag->tag_name = git__strdup(name);
-}
-
 const git_signature *git_tag_tagger(git_tag *t)
 {
 	return t->tagger;
 }
 
-void git_tag_set_tagger(git_tag *tag, const git_signature *tagger_sig)
-{
-	assert(tag && tagger_sig);
-	tag->object.modified = 1;
-
-	git_signature_free(tag->tagger);
-	tag->tagger = git_signature_dup(tagger_sig);
-}
-
 const char *git_tag_message(git_tag *t)
 {
 	assert(t);
 	return t->message;
 }
 
-void git_tag_set_message(git_tag *tag, const char *message)
-{
-	assert(tag && message);
-
-	tag->object.modified = 1;
-
-	if (tag->message)
-		free(tag->message);
-
-	tag->message = git__strdup(message);
-}
-
 static int parse_tag_buffer(git_tag *tag, char *buffer, const char *buffer_end)
 {
 	static const char *tag_types[] = {
 		NULL, "commit\n", "tree\n", "blob\n", "tag\n"
 	};
 
-	git_oid target_oid;
 	unsigned int i, text_len;
 	char *search;
 	int error;
 
-	if ((error = git__parse_oid(&target_oid, &buffer, buffer_end, "object ")) < 0)
+	if ((error = git__parse_oid(&tag->target, &buffer, buffer_end, "object ")) < 0)
 		return error;
 
 	if (buffer + 5 >= buffer_end)
@@ -161,11 +117,6 @@ static int parse_tag_buffer(git_tag *tag, char *buffer, const char *buffer_end)
 	if (tag->type == GIT_OBJ_BAD)
 		return GIT_EOBJCORRUPTED;
 
-	git_object_close(tag->target);
-	error = git_object_lookup(&tag->target, tag->object.repo, &target_oid, tag->type);
-	if (error < 0)
-		return error;
-
 	if (buffer + 4 >= buffer_end)
 		return GIT_EOBJCORRUPTED;
 
@@ -188,9 +139,6 @@ static int parse_tag_buffer(git_tag *tag, char *buffer, const char *buffer_end)
 
 	buffer = search + 1;
 
-	if (tag->tagger != NULL)
-		git_signature_free(tag->tagger);
-
 	tag->tagger = git__malloc(sizeof(git_signature));
 
 	if ((error = git_signature__parse(tag->tagger, &buffer, buffer_end, "tagger ")) != 0)
@@ -198,9 +146,6 @@ static int parse_tag_buffer(git_tag *tag, char *buffer, const char *buffer_end)
 
 	text_len = buffer_end - ++buffer;
 
-	if (tag->message != NULL)
-		free(tag->message);
-
 	tag->message = git__malloc(text_len + 1);
 	memcpy(tag->message, buffer, text_len);
 	tag->message[text_len] = '\0';
@@ -208,26 +153,90 @@ static int parse_tag_buffer(git_tag *tag, char *buffer, const char *buffer_end)
 	return GIT_SUCCESS;
 }
 
-int git_tag__writeback(git_tag *tag, git_odb_source *src)
+int git_tag_create_o(
+		git_oid *oid,
+		git_repository *repo,
+		const char *tag_name,
+		const git_object *target,
+		const git_signature *tagger,
+		const char *message)
 {
-	if (tag->target == NULL || tag->tag_name == NULL || tag->tagger == NULL)
-		return GIT_EMISSINGOBJDATA;
+	return git_tag_create(
+		oid, repo, tag_name, 
+		git_object_id(target),
+		git_object_type(target),
+		tagger, message);
+}
 
-	git__write_oid(src, "object", git_object_id(tag->target));
-	git__source_printf(src, "type %s\n", git_object_type2string(tag->type));
-	git__source_printf(src, "tag %s\n", tag->tag_name);
-	git_signature__write(src, "tagger", tag->tagger);
+int git_tag_create(
+		git_oid *oid,
+		git_repository *repo,
+		const char *tag_name,
+		const git_oid *target,
+		git_otype target_type,
+		const git_signature *tagger,
+		const char *message)
+{
+	size_t final_size = 0;
+	git_odb_stream *stream;
 
-	if (tag->message != NULL)
-		git__source_printf(src, "\n%s", tag->message);
+	const char *type_str;
+	char *tagger_str;
 
-	return GIT_SUCCESS;
+	int type_str_len, tag_name_len, tagger_str_len, message_len;
+	int error;
+
+
+	type_str = git_object_type2string(target_type);
+
+	tagger_str_len = git_signature__write(&tagger_str, "tagger", tagger);
+
+	type_str_len = strlen(type_str);
+	tag_name_len = strlen(tag_name);
+	message_len = strlen(message);
+
+	final_size += GIT_OID_LINE_LENGTH("object");
+	final_size += STRLEN("type ") + type_str_len + 1;
+	final_size += STRLEN("tag ") + tag_name_len + 1;
+	final_size += tagger_str_len;
+	final_size += 1 + message_len;
+
+	if ((error = git_odb_open_wstream(&stream, repo->db, final_size, GIT_OBJ_TAG)) < GIT_SUCCESS)
+		return error;
+
+	git__write_oid(stream, "object", target);
+
+	stream->write(stream, "type ", STRLEN("type "));
+	stream->write(stream, type_str, type_str_len);
+
+	stream->write(stream, "\ntag ", STRLEN("\ntag "));
+	stream->write(stream, tag_name, tag_name_len);
+	stream->write(stream, "\n", 1);
+
+	stream->write(stream, tagger_str, tagger_str_len);
+	free(tagger_str);
+
+	stream->write(stream, "\n", 1);
+	stream->write(stream, message, message_len);
+
+
+	error = stream->finalize_write(oid, stream);
+	stream->free(stream);
+
+	if (error == GIT_SUCCESS) {
+		char ref_name[512];
+		git_reference *new_ref;
+		git__joinpath(ref_name, GIT_REFS_TAGS_DIR, tag_name);
+		error = git_reference_create_oid(&new_ref, repo, ref_name, oid);
+	}
+
+	return error;
 }
 
 
-int git_tag__parse(git_tag *tag)
+int git_tag__parse(git_tag *tag, git_odb_object *obj)
 {
-	assert(tag && tag->object.source.open);
-	return parse_tag_buffer(tag, tag->object.source.raw.data, (char *)tag->object.source.raw.data + tag->object.source.raw.len);
+	assert(tag);
+	return parse_tag_buffer(tag, obj->raw.data, (char *)obj->raw.data + obj->raw.len);
 }
 
diff --git a/src/tag.h b/src/tag.h
index 624fcc654..eddf8fa3a 100644
--- a/src/tag.h
+++ b/src/tag.h
@@ -3,19 +3,20 @@
 
 #include "git2/tag.h"
 #include "repository.h"
+#include "odb.h"
 
 struct git_tag {
 	git_object object;
 
-	git_object *target;
+	git_oid target;
 	git_otype type;
+
 	char *tag_name;
 	git_signature *tagger;
 	char *message;
 };
 
 void git_tag__free(git_tag *tag);
-int git_tag__parse(git_tag *tag);
-int git_tag__writeback(git_tag *tag, git_odb_source *src);
+int git_tag__parse(git_tag *tag, git_odb_object *obj);
 
 #endif
diff --git a/src/thread-utils.h b/src/thread-utils.h
index 0029e4bc1..20d6022ea 100644
--- a/src/thread-utils.h
+++ b/src/thread-utils.h
@@ -1,107 +1,100 @@
 #ifndef INCLUDE_thread_utils_h__
 #define INCLUDE_thread_utils_h__
 
-#if defined(GIT_HAS_PTHREAD)
-	typedef pthread_t git_thread;
-#	define git_thread_create(thread, attr, start_routine, arg) pthread_create(thread, attr, start_routine, arg)
-#	define git_thread_kill(thread) pthread_cancel(thread)
-#	define git_thread_exit(status)	pthread_exit(status)
-#	define git_thread_join(id, status) pthread_join(id, status)
-
-	/* Pthreads Mutex */
-	typedef pthread_mutex_t git_lck;
-#	define GITLCK_INIT      PTHREAD_MUTEX_INITIALIZER
-#	define gitlck_init(a)   pthread_mutex_init(a, NULL)
-#	define gitlck_lock(a)   pthread_mutex_lock(a)
-#	define gitlck_unlock(a) pthread_mutex_unlock(a)
-#	define gitlck_free(a)   pthread_mutex_destroy(a)
-
-	/* Pthreads condition vars */
-	typedef pthread_cond_t git_cnd;
-#	define GITCND_INIT			PTHREAD_COND_INITIALIZER
-#	define gitcnd_init(c, a)	pthread_cond_init(c, a)
-#	define gitcnd_free(c)		pthread_cond_destroy(c)
-#	define gitcnd_wait(c, l)	pthread_cond_wait(c, l)
-#	define gitcnd_signal(c)		pthread_cond_signal(c)
-#	define gitcnd_broadcast(c)	pthread_cond_broadcast(c)
-
-#	if defined(GIT_HAS_ASM_ATOMIC)
-#		include <asm/atomic.h>
-		typedef atomic_t git_refcnt;
-#		define gitrc_init(a, v) atomic_set(a, v)
-#		define gitrc_inc(a)		atomic_inc_return(a)
-#		define gitrc_dec(a)		atomic_dec_and_test(a)
-#		define gitrc_free(a)	(void)0
-#	elif defined(GIT_WIN32)
-		typedef long git_refcnt;
-#		define gitrc_init(a, v)	(*a = v)
-#		define gitrc_inc(a)		(InterlockedIncrement(a))
-#		define gitrc_dec(a)		(!InterlockedDecrement(a))
-#		define gitrc_free(a)	(void)0
-#	else
-		typedef struct { git_lck lock; int counter; } git_refcnt;
-
-		/** Initialize to 0.  No memory barrier is issued. */
-		GIT_INLINE(void) gitrc_init(git_refcnt *p, int value)
-		{
-			gitlck_init(&p->lock);
-			p->counter = value;
-		}
-
-		/**
-		 * Increment.
-		 *
-		 * Atomically increments @p by 1.  A memory barrier is also
-		 * issued before and after the operation.
-		 *
-		 * @param p pointer of type git_refcnt
-		 */
-		GIT_INLINE(void) gitrc_inc(git_refcnt *p)
-		{
-			gitlck_lock(&p->lock);
-			p->counter++;
-			gitlck_unlock(&p->lock);
-		}
-
-		/**
-		 * Decrement and test.
-		 *
-		 * Atomically decrements @p by 1 and returns true if the
-		 * result is 0, or false for all other cases.  A memory
-		 * barrier is also issued before and after the operation.
-		 *
-		 * @param p pointer of type git_refcnt
-		 */
-		GIT_INLINE(int) gitrc_dec(git_refcnt *p)
-		{
-			int c;
-			gitlck_lock(&p->lock);
-			c = --p->counter;
-			gitlck_unlock(&p->lock);
-			return !c;
-		}
-
-		/** Free any resources associated with the counter. */
-#		define gitrc_free(p) gitlck_free(&(p)->lock)
-#	endif
-
-#elif defined(GIT_THREADS)
-#	error GIT_THREADS but no git_lck implementation
 
+
+/* Common operations even if threading has been disabled */
+typedef struct {
+#if defined(_MSC_VER)
+	volatile long val;
 #else
-	/* no threads support */
-	typedef struct { int dummy; } git_lck;
-#	define GIT_MUTEX_INIT   {}
-#	define gitlck_init(a)   (void)0
-#	define gitlck_lock(a)   (void)0
-#	define gitlck_unlock(a) (void)0
-#	define gitlck_free(a)   (void)0
-
-	typedef struct { int counter; } git_refcnt;
-#	define gitrc_init(a,v) ((a)->counter = v)
-#	define gitrc_inc(a)    ((a)->counter++)
-#	define gitrc_dec(a)    (--(a)->counter == 0)
-#	define gitrc_free(a)   (void)0
+	volatile int val;
+#endif
+} git_atomic;
+
+GIT_INLINE(void) git_atomic_set(git_atomic *a, int val)
+{
+	a->val = val;
+}
+
+#ifdef GIT_THREADS
+
+#define git_thread pthread_t
+#define git_thread_create(thread, attr, start_routine, arg) pthread_create(thread, attr, start_routine, arg)
+#define git_thread_kill(thread) pthread_cancel(thread)
+#define git_thread_exit(status)	pthread_exit(status)
+#define git_thread_join(id, status) pthread_join(id, status)
+
+/* Pthreads Mutex */
+#define git_mutex pthread_mutex_t
+#define git_mutex_init(a)   pthread_mutex_init(a, NULL)
+#define git_mutex_lock(a)   pthread_mutex_lock(a)
+#define git_mutex_unlock(a) pthread_mutex_unlock(a)
+#define git_mutex_free(a)   pthread_mutex_destroy(a)
+
+/* Pthreads condition vars -- disabled by now */
+#define git_cond unsigned int //pthread_cond_t
+#define git_cond_init(c, a)	(void)0		//pthread_cond_init(c, a)
+#define git_cond_free(c) (void)0		//pthread_cond_destroy(c)
+#define git_cond_wait(c, l)	(void)0		//pthread_cond_wait(c, l)
+#define git_cond_signal(c)	(void)0		//pthread_cond_signal(c)
+#define git_cond_broadcast(c) (void)0	//pthread_cond_broadcast(c)
+
+GIT_INLINE(int) git_atomic_inc(git_atomic *a)
+{
+#ifdef __GNUC__
+	return __sync_add_and_fetch(&a->val, 1);
+#elif defined(_MSC_VER)
+	return InterlockedIncrement(&a->val);
+#else
+#	error "Unsupported architecture for atomic operations"
+#endif
+}
+
+GIT_INLINE(int) git_atomic_dec(git_atomic *a)
+{
+#ifdef __GNUC__
+	return __sync_sub_and_fetch(&a->val, 1);
+#elif defined(_MSC_VER)
+	return InterlockedDecrement(&a->val);
+#else
+#	error "Unsupported architecture for atomic operations"
+#endif
+}
+
+#else
+
+#define git_thread unsigned int
+#define git_thread_create(thread, attr, start_routine, arg) (void)0
+#define git_thread_kill(thread) (void)0
+#define git_thread_exit(status) (void)0
+#define git_thread_join(id, status) (void)0
+
+/* Pthreads Mutex */
+#define git_mutex unsigned int
+#define git_mutex_init(a) (void)0
+#define git_mutex_lock(a) (void)0
+#define git_mutex_unlock(a) (void)0
+#define git_mutex_free(a) (void)0
+
+/* Pthreads condition vars */
+#define git_cond unsigned int
+#define git_cond_init(c, a)	(void)0
+#define git_cond_free(c) (void)0
+#define git_cond_wait(c, l)	(void)0
+#define git_cond_signal(c) (void)0
+#define git_cond_broadcast(c) (void)0
+
+GIT_INLINE(int) git_atomic_inc(git_atomic *a)
+{
+	return ++a->val;
+}
+
+GIT_INLINE(int) git_atomic_dec(git_atomic *a)
+{
+	return --a->val;
+}
+
 #endif
 
 extern int git_online_cpus(void);
diff --git a/src/tree.c b/src/tree.c
index 702cccbce..31b286e69 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -25,7 +25,6 @@
 
 #include "common.h"
 #include "commit.h"
-#include "revwalk.h"
 #include "tree.h"
 #include "git2/repository.h"
 #include "git2/object.h"
@@ -42,9 +41,11 @@ int entry_search_cmp(const void *key, const void *array_member)
 	return strcmp(filename, entry->filename);
 }
 
+#if 0
 static int valid_attributes(const int attributes) {
 	return attributes >= 0 && attributes <= MAX_FILEMODE; 
 }
+#endif
 
 int entry_sort_cmp(const void *a, const void *b)
 {
@@ -57,13 +58,10 @@ int entry_sort_cmp(const void *a, const void *b)
                                   entry_b->attr & 040000);
 }
 
-void git_tree_clear_entries(git_tree *tree)
+void git_tree__free(git_tree *tree)
 {
 	unsigned int i;
 
-	if (tree == NULL)
-		return;
-
 	for (i = 0; i < tree->entries.length; ++i) {
 		git_tree_entry *e;
 		e = git_vector_get(&tree->entries, i);
@@ -72,32 +70,6 @@ void git_tree_clear_entries(git_tree *tree)
 		free(e);
 	}
 
-	git_vector_clear(&tree->entries);
-	tree->object.modified = 1;
-}
-
-
-git_tree *git_tree__new(void)
-{
-	git_tree *tree;
-
-	tree = git__malloc(sizeof(struct git_tree));
-	if (tree == NULL)
-		return NULL;
-
-	memset(tree, 0x0, sizeof(struct git_tree));
-
-	if (git_vector_init(&tree->entries, DEFAULT_TREE_SIZE, entry_sort_cmp) < GIT_SUCCESS) {
-		free(tree);
-		return NULL;
-	}
-
-	return tree;
-}
-
-void git_tree__free(git_tree *tree)
-{
-	git_tree_clear_entries(tree);
 	git_vector_free(&tree->entries);
 	free(tree);
 }
@@ -107,37 +79,6 @@ const git_oid *git_tree_id(git_tree *c)
 	return git_object_id((git_object *)c);
 }
 
-int git_tree_entry_set_attributes(git_tree_entry *entry, unsigned int attr)
-{
-	assert(entry && entry->owner);
-	
-	if (!valid_attributes(attr)) {
-		return GIT_ERROR;
-	}
-
-	entry->attr = attr;
-	entry->owner->object.modified = 1;
-	return GIT_SUCCESS;
-}
-
-void git_tree_entry_set_name(git_tree_entry *entry, const char *name)
-{
-	assert(entry && entry->owner);
-
-	free(entry->filename);
-	entry->filename = git__strdup(name);
-	git_vector_sort(&entry->owner->entries);
-	entry->owner->object.modified = 1;
-}
-
-void git_tree_entry_set_id(git_tree_entry *entry, const git_oid *oid)
-{
-	assert(entry && entry->owner);
-
-	git_oid_cpy(&entry->oid, oid);
-	entry->owner->object.modified = 1;
-}
-
 unsigned int git_tree_entry_attributes(git_tree_entry *entry)
 {
 	return entry->attr;
@@ -155,15 +96,10 @@ const git_oid *git_tree_entry_id(git_tree_entry *entry)
 	return &entry->oid;
 }
 
-int git_tree_entry_2object(git_object **object_out, git_tree_entry *entry)
+int git_tree_entry_2object(git_object **object_out, git_repository *repo, git_tree_entry *entry)
 {
 	assert(entry && object_out);
-	return git_object_lookup(object_out, entry->owner->object.repo, &entry->oid, GIT_OBJ_ANY);
-}
-
-static void sort_entries(git_tree *tree)
-{
-	git_vector_sort(&tree->entries);
+	return git_object_lookup(object_out, repo, &entry->oid, GIT_OBJ_ANY);
 }
 
 git_tree_entry *git_tree_entry_byname(git_tree *tree, const char *filename)
@@ -172,8 +108,6 @@ git_tree_entry *git_tree_entry_byname(git_tree *tree, const char *filename)
 
 	assert(tree && filename);
 
-	sort_entries(tree);
-
 	idx = git_vector_bsearch2(&tree->entries, entry_search_cmp, filename);
 	if (idx == GIT_ENOTFOUND)
 		return NULL;
@@ -184,9 +118,6 @@ git_tree_entry *git_tree_entry_byname(git_tree *tree, const char *filename)
 git_tree_entry *git_tree_entry_byindex(git_tree *tree, int idx)
 {
 	assert(tree);
-
-	sort_entries(tree);
-
 	return git_vector_get(&tree->entries, (unsigned int)idx);
 }
 
@@ -196,107 +127,12 @@ size_t git_tree_entrycount(git_tree *tree)
 	return tree->entries.length;
 }
 
-int git_tree_add_entry(git_tree_entry **entry_out, git_tree *tree, const git_oid *id, const char *filename, int attributes)
-{
-	git_tree_entry *entry;
-
-	assert(tree && id && filename);
-	if (!valid_attributes(attributes)) {
-	  return GIT_ERROR;
-	}
-
-	if ((entry = git__malloc(sizeof(git_tree_entry))) == NULL)
-		return GIT_ENOMEM;
-
-	memset(entry, 0x0, sizeof(git_tree_entry));
-
-	entry->filename = git__strdup(filename);
-	git_oid_cpy(&entry->oid, id);
-	entry->attr = attributes;
-	entry->owner = tree;
-
-	if (git_vector_insert(&tree->entries, entry) < 0)
-		return GIT_ENOMEM;
-
-	if (entry_out != NULL)
-		*entry_out = entry;
-
-	tree->object.modified = 1;
-	return GIT_SUCCESS;
-}
-
-int git_tree_remove_entry_byindex(git_tree *tree, int idx)
-{
-	git_tree_entry *remove_ptr;
-
-	assert(tree);
-
-	sort_entries(tree);
-
-	remove_ptr = git_vector_get(&tree->entries, (unsigned int)idx);
-	if (remove_ptr == NULL)
-		return GIT_ENOTFOUND;
-
-	free(remove_ptr->filename);
-	free(remove_ptr);
-
-	tree->object.modified = 1;
-
-	return git_vector_remove(&tree->entries, (unsigned int)idx);
-}
-
-int git_tree_remove_entry_byname(git_tree *tree, const char *filename)
-{
-	int idx;
-
-	assert(tree && filename);
-
-	sort_entries(tree);
-
-	idx = git_vector_bsearch2(&tree->entries, entry_search_cmp, filename);
-	if (idx == GIT_ENOTFOUND)
-		return GIT_ENOTFOUND;
-
-	return git_tree_remove_entry_byindex(tree, idx);
-}
-
-int git_tree__writeback(git_tree *tree, git_odb_source *src)
-{
-	size_t i;
-	char filemode[MAX_FILEMODE_BYTES + 1 + 1];
-
-	assert(tree && src);
-
-	if (tree->entries.length == 0)
-		return GIT_EMISSINGOBJDATA;
-
-	sort_entries(tree);
-
-	for (i = 0; i < tree->entries.length; ++i) {
-		git_tree_entry *entry;
-
-		entry = git_vector_get(&tree->entries, i);
-	
-		snprintf(filemode, sizeof(filemode), "%o ", entry->attr);
-		  
-		git__source_write(src, filemode, strlen(filemode));
-		git__source_write(src, entry->filename, strlen(entry->filename) + 1);
-		git__source_write(src, entry->oid.id, GIT_OID_RAWSZ);
-	} 
-
-	return GIT_SUCCESS;
-}
-
-
 static int tree_parse_buffer(git_tree *tree, char *buffer, char *buffer_end)
 {
-	static const size_t avg_entry_size = 40;
-	unsigned int expected_size;
 	int error = GIT_SUCCESS;
 
-	expected_size = (tree->object.source.raw.len / avg_entry_size) + 1;
-
-	git_tree_clear_entries(tree);
+	if (git_vector_init(&tree->entries, DEFAULT_TREE_SIZE, entry_sort_cmp) < GIT_SUCCESS)
+		return GIT_ENOMEM;
 
 	while (buffer < buffer_end) {
 		git_tree_entry *entry;
@@ -310,7 +146,6 @@ static int tree_parse_buffer(git_tree *tree, char *buffer, char *buffer_end)
 		if (git_vector_insert(&tree->entries, entry) < GIT_SUCCESS)
 			return GIT_ENOMEM;
 
-		entry->owner = tree;
 		entry->attr = strtol(buffer, &buffer, 8);
 
 		if (*buffer++ != ' ') {
@@ -337,16 +172,9 @@ static int tree_parse_buffer(git_tree *tree, char *buffer, char *buffer_end)
 	return error;
 }
 
-int git_tree__parse(git_tree *tree)
+int git_tree__parse(git_tree *tree, git_odb_object *obj)
 {
-	char *buffer, *buffer_end;
-
-	assert(tree && tree->object.source.open);
-	assert(!tree->object.in_memory);
-
-	buffer = tree->object.source.raw.data;
-	buffer_end = buffer + tree->object.source.raw.len;
-
-	return tree_parse_buffer(tree, buffer, buffer_end);
+	assert(tree);
+	return tree_parse_buffer(tree, (char *)obj->raw.data, (char *)obj->raw.data + obj->raw.len);
 }
 
diff --git a/src/tree.h b/src/tree.h
index 78500c471..b4e910a9f 100644
--- a/src/tree.h
+++ b/src/tree.h
@@ -3,14 +3,13 @@
 
 #include "git2/tree.h"
 #include "repository.h"
+#include "odb.h"
 #include "vector.h"
 
 struct git_tree_entry {
 	unsigned int attr;
 	char *filename;
 	git_oid oid;
-
-	git_tree *owner;
 };
 
 struct git_tree {
@@ -19,8 +18,6 @@ struct git_tree {
 };
 
 void git_tree__free(git_tree *tree);
-git_tree *git_tree__new(void);
-int git_tree__parse(git_tree *tree);
-int git_tree__writeback(git_tree *tree, git_odb_source *src);
+int git_tree__parse(git_tree *tree, git_odb_object *obj);
 
 #endif
diff --git a/src/util.c b/src/util.c
index c9a8e5fe9..995daf314 100644
--- a/src/util.c
+++ b/src/util.c
@@ -3,6 +3,15 @@
 #include <stdarg.h>
 #include <stdio.h>
 
+void git_strarray_free(git_strarray *array)
+{
+	size_t i;
+	for (i = 0; i < array->count; ++i)
+		free(array->strings[i]);
+
+	free(array->strings);
+}
+
 int git__fmt(char *buf, size_t buf_sz, const char *fmt, ...)
 {
 	va_list va;
@@ -214,6 +223,9 @@ void git__joinpath_n(char *buffer_out, int count, ...)
 		int len;
 
 		path = va_arg(ap, const char *);
+
+		assert((i == 0) || path != buffer_start);
+
 		if (i > 0 && *path == '/' && buffer_out > buffer_start && buffer_out[-1] == '/')
 			path++;
 
diff --git a/src/util.h b/src/util.h
index d5320e15b..653b34d02 100644
--- a/src/util.h
+++ b/src/util.h
@@ -2,6 +2,8 @@
 #define INCLUDE_util_h__
 
 #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
+#define bitsizeof(x)  (CHAR_BIT * sizeof(x))
+#define MSB(x, bits) ((x) & (~0ULL << (bitsizeof(x) - (bits))))
 
 /* 
  * Don't wrap malloc/calloc.
@@ -93,6 +95,10 @@ GIT_INLINE(int) git__is_sizet(git_off_t p)
 extern char *git__strtok(char *output, char *src, char *delimit);
 extern char *git__strtok_keep(char *output, char *src, char *delimit);
 
+#define STRLEN(str) (sizeof(str) - 1)
+
+#define GIT_OID_LINE_LENGTH(header) (STRLEN(header) + 1 + GIT_OID_HEXSZ + 1)
+
 /*
  * Realloc the buffer pointed at by variable 'x' so that it can hold
  * at least 'nr' entries; the number of entries currently allocated
diff --git a/src/win32/pthread.c b/src/win32/pthread.c
new file mode 100644
index 000000000..f47364a76
--- /dev/null
+++ b/src/win32/pthread.c
@@ -0,0 +1,86 @@
+/*
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * In addition to the permissions in the GNU General Public License,
+ * the authors give you unlimited permission to link the compiled
+ * version of this file into combinations with other programs,
+ * and to distribute those combinations without any restriction
+ * coming from the use of this file.  (The General Public License
+ * restrictions do apply in other respects; for example, they cover
+ * modification of the file, and distribution when not linked into
+ * a combined executable.)
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ *  Original code by Ramiro Polla (Public Domain)
+ */
+
+#include "pthread.h"
+
+int pthread_create(pthread_t *GIT_RESTRICT thread,
+                   const pthread_attr_t *GIT_RESTRICT GIT_UNUSED(attr),
+                   void *(*start_routine)(void*), void *GIT_RESTRICT arg)
+{
+	GIT_UNUSED_ARG(attr);
+	*thread = (pthread_t) CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)start_routine, arg, 0, NULL);
+	return *thread ? GIT_SUCCESS : GIT_EOSERR;
+}
+
+int pthread_join(pthread_t thread, void **value_ptr)
+{
+    int ret;
+    ret = WaitForSingleObject(thread, INFINITE);
+    if (ret && value_ptr)
+        GetExitCodeThread(thread, (void*) value_ptr);
+    return -(!!ret);
+}
+
+int pthread_mutex_init(pthread_mutex_t *GIT_RESTRICT mutex,
+                       const pthread_mutexattr_t *GIT_RESTRICT GIT_UNUSED(mutexattr))
+{
+	GIT_UNUSED_ARG(mutexattr);
+    InitializeCriticalSection(mutex);
+    return 0;
+}
+
+int pthread_mutex_destroy(pthread_mutex_t *mutex)
+{
+    int ret;
+    ret = CloseHandle(mutex);
+    return -(!ret);
+}
+
+int pthread_mutex_lock(pthread_mutex_t *mutex)
+{
+    EnterCriticalSection(mutex);
+    return 0;
+}
+
+int pthread_mutex_unlock(pthread_mutex_t *mutex)
+{
+    LeaveCriticalSection(mutex);
+    return 0;
+}
+
+int pthread_num_processors_np(void)
+{
+    DWORD_PTR p, s;
+    int n = 0;
+
+    if (GetProcessAffinityMask(GetCurrentProcess(), &p, &s))
+        for (; p; p >>= 1)
+            n += p&1;
+
+    return n ? n : 1;
+}
+
diff --git a/src/win32/pthread.h b/src/win32/pthread.h
new file mode 100644
index 000000000..10949f1eb
--- /dev/null
+++ b/src/win32/pthread.h
@@ -0,0 +1,60 @@
+/*
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2,
+ * as published by the Free Software Foundation.
+ *
+ * In addition to the permissions in the GNU General Public License,
+ * the authors give you unlimited permission to link the compiled
+ * version of this file into combinations with other programs,
+ * and to distribute those combinations without any restriction
+ * coming from the use of this file.  (The General Public License
+ * restrictions do apply in other respects; for example, they cover
+ * modification of the file, and distribution when not linked into
+ * a combined executable.)
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ *  Original code by Ramiro Polla (Public Domain)
+ */
+
+#ifndef GIT_PTHREAD_H
+#define GIT_PTHREAD_H
+
+#include "../common.h"
+
+#if defined (_MSC_VER)
+#	define GIT_RESTRICT __restrict
+#else
+#	define GIT_RESTRICT __restrict__
+#endif
+
+typedef int pthread_mutexattr_t;
+typedef int pthread_condattr_t;
+typedef int pthread_attr_t;
+typedef CRITICAL_SECTION pthread_mutex_t;
+typedef HANDLE pthread_t;
+
+#define PTHREAD_MUTEX_INITIALIZER {(void*)-1};
+
+int pthread_create(pthread_t *GIT_RESTRICT,
+                   const pthread_attr_t *GIT_RESTRICT,
+                   void *(*start_routine)(void*), void *__restrict);
+
+int pthread_join(pthread_t, void **);
+
+int pthread_mutex_init(pthread_mutex_t *GIT_RESTRICT, const pthread_mutexattr_t *GIT_RESTRICT);
+int pthread_mutex_destroy(pthread_mutex_t *);
+int pthread_mutex_lock(pthread_mutex_t *);
+int pthread_mutex_unlock(pthread_mutex_t *);
+
+int pthread_num_processors_np(void);
+
+#endif