Implement git_odb_write()

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Andreas Ericsson <ae@op5.se>

4 files changed, 734 insertions, 4 deletions

diff --git a/src/git/odb.h b/src/git/odb.h
index 8a8cd3e5f..58b932645 100644
--- a/src/git/odb.h
+++ b/src/git/odb.h
@@ -96,6 +96,18 @@ GIT_EXTERN(int) git_odb__read_packed(git_obj *out, git_odb *db, const git_oid *i
 GIT_EXTERN(int) git_odb__read_loose(git_obj *out, git_odb *db, const git_oid *id);
 
 /**
+ * Write an object to the database.
+ *
+ * @param id identity of the object written.
+ * @param db database to which the object should be written.
+ * @param obj object descriptor for the object to write.
+ * @return
+ * - GIT_SUCCESS if the object was written;
+ * - GIT_ERROR otherwise.
+ */
+GIT_EXTERN(int) git_odb_write(git_oid *id, git_odb *db, git_obj *obj);
+
+/**
  * Release all memory used by the obj structure.
  *
  * As a result of this call, obj->data will be set to NULL.
diff --git a/src/odb.c b/src/odb.c
index 6b7d1f799..5f10ae02d 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -85,6 +85,11 @@ struct git_odb {
 	/** Alternate databases to search. */
 	git_odb **alternates;
 	size_t n_alternates;
+
+	/** loose object zlib compression level. */
+	int object_zlib_level;
+	/** loose object file fsync flag. */
+	int fsync_object_files;
 };
 
 typedef struct {  /* object header data */
@@ -158,13 +163,12 @@ static int format_object_header(char *hdr, size_t n, git_obj *obj)
 	return len+1;
 }
 
-int git_obj_hash(git_oid *id, git_obj *obj)
+static int hash_obj(git_oid *id, char *hdr, size_t n, int *len, git_obj *obj)
 {
 	git_buf_vec vec[2];
-	char hdr[64];
 	int  hdrlen;
 
-	assert(id && obj);
+	assert(id && hdr && len && obj);
 
 	if (!git_obj__loose_object_type(obj->type))
 		return GIT_ERROR;
@@ -172,9 +176,11 @@ int git_obj_hash(git_oid *id, git_obj *obj)
 	if (!obj->data && obj->len != 0)
 		return GIT_ERROR;
 
-	if ((hdrlen = format_object_header(hdr, sizeof(hdr), obj)) < 0)
+	if ((hdrlen = format_object_header(hdr, n, obj)) < 0)
 		return GIT_ERROR;
 
+	*len = hdrlen;
+
 	vec[0].data = hdr;
 	vec[0].len  = hdrlen;
 	vec[1].data = obj->data;
@@ -185,6 +191,16 @@ int git_obj_hash(git_oid *id, git_obj *obj)
 	return GIT_SUCCESS;
 }
 
+int git_obj_hash(git_oid *id, git_obj *obj)
+{
+	char hdr[64];
+	int  hdrlen;
+
+	assert(id && obj);
+
+	return hash_obj(id, hdr, sizeof(hdr), &hdrlen, obj);
+}
+
 static size_t object_file_name(char *name, size_t n, char *dir, const git_oid *id)
 {
 	size_t len = strlen(dir);
@@ -483,6 +499,125 @@ static int inflate_disk_obj(git_obj *out, gitfo_buf *obj)
 	return GIT_SUCCESS;
 }
 
+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);
+	size_t dirlen;
+
+	if ((dirlen = git__dirname(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 int deflate_buf(z_stream *s, void *in, size_t len, int flush)
+{
+	int status = Z_OK;
+
+	set_stream_input(s, in, len);
+	while (status == Z_OK) {
+		status = deflate(s, flush);
+		if (s->avail_in == 0)
+			break;
+	}
+	return status;
+}
+
+static int deflate_obj(gitfo_buf *buf, char *hdr, int hdrlen, git_obj *obj, int level)
+{
+	z_stream zs;
+	int status;
+	size_t size;
+
+	assert(buf && !buf->data && hdr && obj);
+	assert(level == Z_DEFAULT_COMPRESSION || (level >= 0 && level <= 9));
+
+	buf->data = NULL;
+	buf->len  = 0;
+	init_stream(&zs, NULL, 0);
+
+	if (deflateInit(&zs, level) < Z_OK)
+		return GIT_ERROR;
+
+	size = deflateBound(&zs, hdrlen + obj->len);
+
+	if ((buf->data = git__malloc(size)) == NULL) {
+		deflateEnd(&zs);
+		return GIT_ERROR;
+	}
+
+	set_stream_output(&zs, buf->data, size);
+
+	/* compress the header */
+	status = deflate_buf(&zs, hdr, hdrlen, Z_NO_FLUSH);
+
+	/* if header compressed OK, compress the object */
+	if (status == Z_OK)
+		status = deflate_buf(&zs, obj->data, obj->len, Z_FINISH);
+
+	if (status != Z_STREAM_END) {
+		deflateEnd(&zs);
+		free(buf->data);
+		buf->data = NULL;
+		return GIT_ERROR;
+	}
+
+	buf->len = zs.total_out;
+	deflateEnd(&zs);
+
+	return GIT_SUCCESS;
+}
+
+static int write_obj(gitfo_buf *buf, git_oid *id, git_odb *db)
+{
+	char file[GIT_PATH_MAX];
+	char temp[GIT_PATH_MAX];
+	git_file fd;
+
+	if (object_file_name(file, sizeof(file), db->objects_dir, id))
+		return GIT_ERROR;
+
+	if (make_temp_file(&fd, temp, sizeof(temp), file) < 0)
+		return GIT_ERROR;
+
+	if (gitfo_write(fd, buf->data, buf->len) < 0) {
+		gitfo_close(fd);
+		gitfo_unlink(temp);
+		return GIT_ERROR;
+	}
+
+	if (db->fsync_object_files)
+		gitfo_fsync(fd);
+	gitfo_close(fd);
+	gitfo_chmod(temp, 0444);
+
+	if (gitfo_move_file(temp, file) < 0) {
+		gitfo_unlink(temp);
+		return GIT_ERROR;
+	}
+
+	return GIT_SUCCESS;
+}
+
 static int open_alternates(git_odb *db)
 {
 	unsigned n = 0;
@@ -891,6 +1026,9 @@ int git_odb_open(git_odb **out, const char *objects_dir)
 
 	gitlck_init(&db->lock);
 
+	db->object_zlib_level = Z_BEST_SPEED;
+	db->fsync_object_files = 0;
+
 	*out = db;
 	return GIT_SUCCESS;
 }
@@ -1004,3 +1142,30 @@ int git_odb__read_packed(git_obj *out, git_odb *db, const git_oid *id)
 	return GIT_ENOTFOUND;
 }
 
+int git_odb_write(git_oid *id, git_odb *db, git_obj *obj)
+{
+	char hdr[64];
+	int  hdrlen;
+	gitfo_buf buf = GITFO_BUF_INIT;
+
+	assert(id && db && obj);
+
+	if (hash_obj(id, hdr, sizeof(hdr), &hdrlen, obj) < 0)
+		return GIT_ERROR;
+
+	if (git_odb_exists(db, id))
+		return GIT_SUCCESS;
+
+	if (deflate_obj(&buf, hdr, hdrlen, obj, db->object_zlib_level) < 0)
+		return GIT_ERROR;
+
+	if (write_obj(&buf, id, db) < 0) {
+		gitfo_free_buf(&buf);
+		return GIT_ERROR;
+	}
+
+	gitfo_free_buf(&buf);
+
+	return GIT_SUCCESS;
+}
+
diff --git a/tests/NAMING b/tests/NAMING
index c1052be27..73bb602a7 100644
--- a/tests/NAMING
+++ b/tests/NAMING
@@ -18,3 +18,5 @@ Categories
       addressable store.
 
 02__: Basic object read access.
+
+03__: Basic object writing.
diff --git a/tests/t0301-write.c b/tests/t0301-write.c
new file mode 100644
index 000000000..f161ce12c
--- /dev/null
+++ b/tests/t0301-write.c
@@ -0,0 +1,551 @@
+
+#include "test_lib.h"
+#include <git/odb.h>
+#include "fileops.h"
+
+static char *odb_dir = "test-objects";
+
+typedef struct object_data {
+    char *id;     /* object id (sha1)                          */
+    char *dir;    /* object store (fan-out) directory name     */
+    char *file;   /* object store filename                     */
+} object_data;
+
+static object_data commit = {
+    "3d7f8a6af076c8c3f20071a8935cdbe8228594d1",
+    "test-objects/3d",
+    "test-objects/3d/7f8a6af076c8c3f20071a8935cdbe8228594d1",
+};
+
+static unsigned char commit_data[] = {
+    0x74, 0x72, 0x65, 0x65, 0x20, 0x64, 0x66, 0x66,
+    0x32, 0x64, 0x61, 0x39, 0x30, 0x62, 0x32, 0x35,
+    0x34, 0x65, 0x31, 0x62, 0x65, 0x62, 0x38, 0x38,
+    0x39, 0x64, 0x31, 0x66, 0x31, 0x66, 0x31, 0x32,
+    0x38, 0x38, 0x62, 0x65, 0x31, 0x38, 0x30, 0x33,
+    0x37, 0x38, 0x32, 0x64, 0x66, 0x0a, 0x61, 0x75,
+    0x74, 0x68, 0x6f, 0x72, 0x20, 0x41, 0x20, 0x55,
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+    0x75, 0x74, 0x68, 0x6f, 0x72, 0x40, 0x65, 0x78,
+    0x61, 0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f,
+    0x6d, 0x3e, 0x20, 0x31, 0x32, 0x32, 0x37, 0x38,
+    0x31, 0x34, 0x32, 0x39, 0x37, 0x20, 0x2b, 0x30,
+    0x30, 0x30, 0x30, 0x0a, 0x63, 0x6f, 0x6d, 0x6d,
+    0x69, 0x74, 0x74, 0x65, 0x72, 0x20, 0x43, 0x20,
+    0x4f, 0x20, 0x4d, 0x69, 0x74, 0x74, 0x65, 0x72,
+    0x20, 0x3c, 0x63, 0x6f, 0x6d, 0x6d, 0x69, 0x74,
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+    0x20, 0x31, 0x32, 0x32, 0x37, 0x38, 0x31, 0x34,
+    0x32, 0x39, 0x37, 0x20, 0x2b, 0x30, 0x30, 0x30,
+    0x30, 0x0a, 0x0a, 0x41, 0x20, 0x6f, 0x6e, 0x65,
+    0x2d, 0x6c, 0x69, 0x6e, 0x65, 0x20, 0x63, 0x6f,
+    0x6d, 0x6d, 0x69, 0x74, 0x20, 0x73, 0x75, 0x6d,
+    0x6d, 0x61, 0x72, 0x79, 0x0a, 0x0a, 0x54, 0x68,
+    0x65, 0x20, 0x62, 0x6f, 0x64, 0x79, 0x20, 0x6f,
+    0x66, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6f,
+    0x6d, 0x6d, 0x69, 0x74, 0x20, 0x6d, 0x65, 0x73,
+    0x73, 0x61, 0x67, 0x65, 0x2c, 0x20, 0x63, 0x6f,
+    0x6e, 0x74, 0x61, 0x69, 0x6e, 0x69, 0x6e, 0x67,
+    0x20, 0x66, 0x75, 0x72, 0x74, 0x68, 0x65, 0x72,
+    0x20, 0x65, 0x78, 0x70, 0x6c, 0x61, 0x6e, 0x61,
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+    0x74, 0x68, 0x65, 0x20, 0x70, 0x75, 0x72, 0x70,
+    0x6f, 0x73, 0x65, 0x20, 0x6f, 0x66, 0x20, 0x74,
+    0x68, 0x65, 0x20, 0x63, 0x68, 0x61, 0x6e, 0x67,
+    0x65, 0x73, 0x20, 0x69, 0x6e, 0x74, 0x72, 0x6f,
+    0x64, 0x75, 0x63, 0x65, 0x64, 0x20, 0x62, 0x79,
+    0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6f, 0x6d,
+    0x6d, 0x69, 0x74, 0x2e, 0x0a, 0x0a, 0x53, 0x69,
+    0x67, 0x6e, 0x65, 0x64, 0x2d, 0x6f, 0x66, 0x2d,
+    0x62, 0x79, 0x3a, 0x20, 0x41, 0x20, 0x55, 0x20,
+    0x54, 0x68, 0x6f, 0x72, 0x20, 0x3c, 0x61, 0x75,
+    0x74, 0x68, 0x6f, 0x72, 0x40, 0x65, 0x78, 0x61,
+    0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f, 0x6d,
+    0x3e, 0x0a,
+};
+
+static git_obj commit_obj = {
+	commit_data,
+	sizeof(commit_data),
+	GIT_OBJ_COMMIT
+};
+
+static object_data tree = {
+    "dff2da90b254e1beb889d1f1f1288be1803782df",
+    "test-objects/df",
+    "test-objects/df/f2da90b254e1beb889d1f1f1288be1803782df",
+};
+
+static unsigned char tree_data[] = {
+    0x31, 0x30, 0x30, 0x36, 0x34, 0x34, 0x20, 0x6f,
+    0x6e, 0x65, 0x00, 0x8b, 0x13, 0x78, 0x91, 0x79,
+    0x1f, 0xe9, 0x69, 0x27, 0xad, 0x78, 0xe6, 0x4b,
+    0x0a, 0xad, 0x7b, 0xde, 0xd0, 0x8b, 0xdc, 0x31,
+    0x30, 0x30, 0x36, 0x34, 0x34, 0x20, 0x73, 0x6f,
+    0x6d, 0x65, 0x00, 0xfd, 0x84, 0x30, 0xbc, 0x86,
+    0x4c, 0xfc, 0xd5, 0xf1, 0x0e, 0x55, 0x90, 0xf8,
+    0xa4, 0x47, 0xe0, 0x1b, 0x94, 0x2b, 0xfe, 0x31,
+    0x30, 0x30, 0x36, 0x34, 0x34, 0x20, 0x74, 0x77,
+    0x6f, 0x00, 0x78, 0x98, 0x19, 0x22, 0x61, 0x3b,
+    0x2a, 0xfb, 0x60, 0x25, 0x04, 0x2f, 0xf6, 0xbd,
+    0x87, 0x8a, 0xc1, 0x99, 0x4e, 0x85, 0x31, 0x30,
+    0x30, 0x36, 0x34, 0x34, 0x20, 0x7a, 0x65, 0x72,
+    0x6f, 0x00, 0xe6, 0x9d, 0xe2, 0x9b, 0xb2, 0xd1,
+    0xd6, 0x43, 0x4b, 0x8b, 0x29, 0xae, 0x77, 0x5a,
+    0xd8, 0xc2, 0xe4, 0x8c, 0x53, 0x91,
+};
+
+static git_obj tree_obj = {
+	tree_data,
+	sizeof(tree_data),
+	GIT_OBJ_TREE
+};
+
+static object_data tag = {
+    "09d373e1dfdc16b129ceec6dd649739911541e05",
+    "test-objects/09",
+    "test-objects/09/d373e1dfdc16b129ceec6dd649739911541e05",
+};
+
+static unsigned char tag_data[] = {
+    0x6f, 0x62, 0x6a, 0x65, 0x63, 0x74, 0x20, 0x33,
+    0x64, 0x37, 0x66, 0x38, 0x61, 0x36, 0x61, 0x66,
+    0x30, 0x37, 0x36, 0x63, 0x38, 0x63, 0x33, 0x66,
+    0x32, 0x30, 0x30, 0x37, 0x31, 0x61, 0x38, 0x39,
+    0x33, 0x35, 0x63, 0x64, 0x62, 0x65, 0x38, 0x32,
+    0x32, 0x38, 0x35, 0x39, 0x34, 0x64, 0x31, 0x0a,
+    0x74, 0x79, 0x70, 0x65, 0x20, 0x63, 0x6f, 0x6d,
+    0x6d, 0x69, 0x74, 0x0a, 0x74, 0x61, 0x67, 0x20,
+    0x76, 0x30, 0x2e, 0x30, 0x2e, 0x31, 0x0a, 0x74,
+    0x61, 0x67, 0x67, 0x65, 0x72, 0x20, 0x43, 0x20,
+    0x4f, 0x20, 0x4d, 0x69, 0x74, 0x74, 0x65, 0x72,
+    0x20, 0x3c, 0x63, 0x6f, 0x6d, 0x6d, 0x69, 0x74,
+    0x74, 0x65, 0x72, 0x40, 0x65, 0x78, 0x61, 0x6d,
+    0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f, 0x6d, 0x3e,
+    0x20, 0x31, 0x32, 0x32, 0x37, 0x38, 0x31, 0x34,
+    0x32, 0x39, 0x37, 0x20, 0x2b, 0x30, 0x30, 0x30,
+    0x30, 0x0a, 0x0a, 0x54, 0x68, 0x69, 0x73, 0x20,
+    0x69, 0x73, 0x20, 0x74, 0x68, 0x65, 0x20, 0x74,
+    0x61, 0x67, 0x20, 0x6f, 0x62, 0x6a, 0x65, 0x63,
+    0x74, 0x20, 0x66, 0x6f, 0x72, 0x20, 0x72, 0x65,
+    0x6c, 0x65, 0x61, 0x73, 0x65, 0x20, 0x76, 0x30,
+    0x2e, 0x30, 0x2e, 0x31, 0x0a,
+};
+
+static git_obj tag_obj = {
+	tag_data,
+	sizeof(tag_data),
+	GIT_OBJ_TAG
+};
+
+static object_data zero = {
+    "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391",
+    "test-objects/e6",
+    "test-objects/e6/9de29bb2d1d6434b8b29ae775ad8c2e48c5391",
+};
+
+static unsigned char zero_data[] = {
+    0x00  /* dummy data */
+};
+
+static git_obj zero_obj = {
+	zero_data,
+	0,
+	GIT_OBJ_BLOB
+};
+
+static object_data one = {
+    "8b137891791fe96927ad78e64b0aad7bded08bdc",
+    "test-objects/8b",
+    "test-objects/8b/137891791fe96927ad78e64b0aad7bded08bdc",
+};
+
+static unsigned char one_data[] = {
+    0x0a,
+};
+
+static git_obj one_obj = {
+	one_data,
+	sizeof(one_data),
+	GIT_OBJ_BLOB
+};
+
+static object_data two = {
+    "78981922613b2afb6025042ff6bd878ac1994e85",
+    "test-objects/78",
+    "test-objects/78/981922613b2afb6025042ff6bd878ac1994e85",
+};
+
+static unsigned char two_data[] = {
+    0x61, 0x0a,
+};
+
+static git_obj two_obj = {
+	two_data,
+	sizeof(two_data),
+	GIT_OBJ_BLOB
+};
+
+static object_data some = {
+    "fd8430bc864cfcd5f10e5590f8a447e01b942bfe",
+    "test-objects/fd",
+    "test-objects/fd/8430bc864cfcd5f10e5590f8a447e01b942bfe",
+};
+
+static unsigned char some_data[] = {
+    0x2f, 0x2a, 0x0a, 0x20, 0x2a, 0x20, 0x54, 0x68,
+    0x69, 0x73, 0x20, 0x66, 0x69, 0x6c, 0x65, 0x20,
+    0x69, 0x73, 0x20, 0x66, 0x72, 0x65, 0x65, 0x20,
+    0x73, 0x6f, 0x66, 0x74, 0x77, 0x61, 0x72, 0x65,
+    0x3b, 0x20, 0x79, 0x6f, 0x75, 0x20, 0x63, 0x61,
+    0x6e, 0x20, 0x72, 0x65, 0x64, 0x69, 0x73, 0x74,
+    0x72, 0x69, 0x62, 0x75, 0x74, 0x65, 0x20, 0x69,
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+    0x20, 0x6d, 0x6f, 0x64, 0x69, 0x66, 0x79, 0x0a,
+    0x20, 0x2a, 0x20, 0x69, 0x74, 0x20, 0x75, 0x6e,
+    0x64, 0x65, 0x72, 0x20, 0x74, 0x68, 0x65, 0x20,
+    0x74, 0x65, 0x72, 0x6d, 0x73, 0x20, 0x6f, 0x66,
+    0x20, 0x74, 0x68, 0x65, 0x20, 0x47, 0x4e, 0x55,
+    0x20, 0x47, 0x65, 0x6e, 0x65, 0x72, 0x61, 0x6c,
+    0x20, 0x50, 0x75, 0x62, 0x6c, 0x69, 0x63, 0x20,
+    0x4c, 0x69, 0x63, 0x65, 0x6e, 0x73, 0x65, 0x2c,
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+    0x55, 0x53, 0x41, 0x2e, 0x0a, 0x20, 0x2a, 0x2f,
+    0x0a,
+};
+
+static git_obj some_obj = {
+	some_data,
+	sizeof(some_data),
+	GIT_OBJ_BLOB
+};
+
+static int make_odb_dir(void)
+{
+    if (gitfo_mkdir(odb_dir, 0755) < 0) {
+        if (errno == EEXIST) {
+            fprintf(stderr, "odb directory \"%s\" already exists!\n", odb_dir);
+            return -1;
+        }
+        fprintf(stderr, "can't make odb directory \"%s\"\n", odb_dir);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int remove_object_files(object_data *d)
+{
+    if (gitfo_unlink(d->file) < 0) {
+        fprintf(stderr, "can't delete object file \"%s\"\n", d->file);
+        return -1;
+    }
+    if ((gitfo_rmdir(d->dir) < 0) && (errno != ENOTEMPTY)) {
+        fprintf(stderr, "can't remove object directory \"%s\"\n", d->dir);
+        return -1;
+    }
+
+    if (gitfo_rmdir(odb_dir) < 0) {
+        fprintf(stderr, "can't remove odb directory \"%s\"\n", odb_dir);
+        return -1;
+    }
+
+    return 0;
+}
+
+static int check_object_files(object_data *d)
+{
+    if (gitfo_exists(d->dir) < 0)
+	    return -1;
+    if (gitfo_exists(d->file) < 0)
+	    return -1;
+    return 0;
+}
+
+static int cmp_objects(git_obj *o1, git_obj *o2)
+{
+    if (o1->type != o2->type)
+        return -1;
+    if (o1->len != o2->len)
+        return -1;
+    if ((o1->len > 0) && (memcmp(o1->data, o2->data, o1->len) != 0))
+        return -1;
+    return 0;
+}
+
+BEGIN_TEST(write_commit)
+    git_odb *db;
+    git_oid id1, id2;
+    git_obj obj;
+
+    must_pass(make_odb_dir());
+    must_pass(git_odb_open(&db, odb_dir));
+    must_pass(git_oid_mkstr(&id1, commit.id));
+
+    must_pass(git_odb_write(&id2, db, &commit_obj));
+    must_be_true(git_oid_cmp(&id1, &id2) == 0);
+    must_pass(check_object_files(&commit));
+
+    must_pass(git_odb__read_loose(&obj, db, &id1));
+    must_pass(cmp_objects(&obj, &commit_obj));
+
+    git_obj_close(&obj);
+    git_odb_close(db);
+    must_pass(remove_object_files(&commit));
+END_TEST
+
+BEGIN_TEST(write_tree)
+    git_odb *db;
+    git_oid id1, id2;
+    git_obj obj;
+
+    must_pass(make_odb_dir());
+    must_pass(git_odb_open(&db, odb_dir));
+    must_pass(git_oid_mkstr(&id1, tree.id));
+
+    must_pass(git_odb_write(&id2, db, &tree_obj));
+    must_be_true(git_oid_cmp(&id1, &id2) == 0);
+    must_pass(check_object_files(&tree));
+
+    must_pass(git_odb__read_loose(&obj, db, &id1));
+    must_pass(cmp_objects(&obj, &tree_obj));
+
+    git_obj_close(&obj);
+    git_odb_close(db);
+    must_pass(remove_object_files(&tree));
+END_TEST
+
+BEGIN_TEST(write_tag)
+    git_odb *db;
+    git_oid id1, id2;
+    git_obj obj;
+
+    must_pass(make_odb_dir());
+    must_pass(git_odb_open(&db, odb_dir));
+    must_pass(git_oid_mkstr(&id1, tag.id));
+
+    must_pass(git_odb_write(&id2, db, &tag_obj));
+    must_be_true(git_oid_cmp(&id1, &id2) == 0);
+    must_pass(check_object_files(&tag));
+
+    must_pass(git_odb__read_loose(&obj, db, &id1));
+    must_pass(cmp_objects(&obj, &tag_obj));
+
+    git_obj_close(&obj);
+    git_odb_close(db);
+    must_pass(remove_object_files(&tag));
+END_TEST
+
+BEGIN_TEST(write_zero)
+    git_odb *db;
+    git_oid id1, id2;
+    git_obj obj;
+
+    must_pass(make_odb_dir());
+    must_pass(git_odb_open(&db, odb_dir));
+    must_pass(git_oid_mkstr(&id1, zero.id));
+
+    must_pass(git_odb_write(&id2, db, &zero_obj));
+    must_be_true(git_oid_cmp(&id1, &id2) == 0);
+    must_pass(check_object_files(&zero));
+
+    must_pass(git_odb__read_loose(&obj, db, &id1));
+    must_pass(cmp_objects(&obj, &zero_obj));
+
+    git_obj_close(&obj);
+    git_odb_close(db);
+    must_pass(remove_object_files(&zero));
+END_TEST
+
+BEGIN_TEST(write_one)
+    git_odb *db;
+    git_oid id1, id2;
+    git_obj obj;
+
+    must_pass(make_odb_dir());
+    must_pass(git_odb_open(&db, odb_dir));
+    must_pass(git_oid_mkstr(&id1, one.id));
+
+    must_pass(git_odb_write(&id2, db, &one_obj));
+    must_be_true(git_oid_cmp(&id1, &id2) == 0);
+    must_pass(check_object_files(&one));
+
+    must_pass(git_odb__read_loose(&obj, db, &id1));
+    must_pass(cmp_objects(&obj, &one_obj));
+
+    git_obj_close(&obj);
+    git_odb_close(db);
+    must_pass(remove_object_files(&one));
+END_TEST
+
+BEGIN_TEST(write_two)
+    git_odb *db;
+    git_oid id1, id2;
+    git_obj obj;
+
+    must_pass(make_odb_dir());
+    must_pass(git_odb_open(&db, odb_dir));
+    must_pass(git_oid_mkstr(&id1, two.id));
+
+    must_pass(git_odb_write(&id2, db, &two_obj));
+    must_be_true(git_oid_cmp(&id1, &id2) == 0);
+    must_pass(check_object_files(&two));
+
+    must_pass(git_odb__read_loose(&obj, db, &id1));
+    must_pass(cmp_objects(&obj, &two_obj));
+
+    git_obj_close(&obj);
+    git_odb_close(db);
+    must_pass(remove_object_files(&two));
+END_TEST
+
+BEGIN_TEST(write_some)
+    git_odb *db;
+    git_oid id1, id2;
+    git_obj obj;
+
+    must_pass(make_odb_dir());
+    must_pass(git_odb_open(&db, odb_dir));
+    must_pass(git_oid_mkstr(&id1, some.id));
+
+    must_pass(git_odb_write(&id2, db, &some_obj));
+    must_be_true(git_oid_cmp(&id1, &id2) == 0);
+    must_pass(check_object_files(&some));
+
+    must_pass(git_odb__read_loose(&obj, db, &id1));
+    must_pass(cmp_objects(&obj, &some_obj));
+
+    git_obj_close(&obj);
+    git_odb_close(db);
+    must_pass(remove_object_files(&some));
+END_TEST
+