Redesigned the walking/object lookup interface

The old 'git_revpool' object has been removed and
split into two distinct objects with separate
functionality, in order to have separate methods for
object management and object walking.

*	A new object 'git_repository' does the high-level
	management of a repository's objects (commits, trees,
	tags, etc) on top of a 'git_odb'.

	Eventually, it will also manage other repository
	attributes (e.g. tag resolution, references, etc).

	See: src/git/repository.h

*	A new external method
		'git_repository_lookup(repo, oid, type)'
	has been added to the 'git_repository' API.

	All object lookups (git_XXX_lookup()) are now
	wrappers to this method, and duplicated code
	has been removed. The method does automatic type
	checking and returns a generic 'git_revpool_object'
	that can be cast to any specific object.

	See: src/git/repository.h

*	The external methods for object parsing of repository
	objects (git_XXX_parse()) have been removed.

	Loading objects from the repository is now managed
	through the 'lookup' functions. These objects are
	loaded with minimal information, and the relevant
	parsing is done automatically when the user requests
	any of the parsed attributes through accessor methods.

	An attribute has been added to 'git_repository' in
	order to force the parsing of all the repository objects
	immediately after lookup.

	See: src/git/commit.h
	See: src/git/tag.h
	See: src/git/tree.h

*	The previous walking functionality of the revpool
	is now found in 'git_revwalk', which does the actual
	revision walking on a repository; the attributes
	when walking through commits in a database have been
	decoupled from the actual commit objects.
	This increases performance when accessing commits
	during the walk and allows to have several
	'git_revwalk' instances working at the same time on
	top of the same repository, without having to load
	commits in memory several times.

	See: src/git/revwalk.h

*	The old 'git_revpool_table' has been renamed to
	'git_hashtable' and now works as a generic hashtable
	with support for any kind of object and custom hash
	functions.

	See: src/hashtable.h

*	All the relevant unit tests have been updated, renamed
	and grouped accordingly.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

7 files changed, 117 insertions, 88 deletions

diff --git a/src/git/commit.h b/src/git/commit.h
index 89f0929c9..56243c5be 100644
--- a/src/git/commit.h
+++ b/src/git/commit.h
@@ -4,6 +4,7 @@
 #include "common.h"
 #include "oid.h"
 #include "tree.h"
+#include "repository.h"
 
 /**
  * @file git/commit.h
@@ -18,31 +19,16 @@ GIT_BEGIN_DECL
 typedef struct git_commit git_commit;
 
 /**
- * Locate a reference to a commit without loading it.
+ * Lookup a commit object from a repository.
  * The generated commit object is owned by the revision
- * pool and shall not be freed by the user.
+ * repo and shall not be freed by the user.
  *
- * @param pool the pool to use when locating the commit.
+ * @param repo the repo to use when locating the commit.
  * @param id identity of the commit to locate.  If the object is
  *        an annotated tag it will be peeled back to the commit.
  * @return the commit; NULL if the commit could not be created
  */
-GIT_EXTERN(git_commit *) git_commit_lookup(git_revpool *pool, const git_oid *id);
-
-/**
- * Locate a reference to a commit, and try to load and parse it it from
- * the commit cache or the object database.
- * The generated commit object is owned by the revision
- * pool and shall not be freed by the user.
- *
- * @param pool the pool to use when parsing/caching the commit.
- * @param id identity of the commit to locate.  If the object is
- *        an annotated tag it will be peeled back to the commit.
- * @return the commit; NULL if the commit does not exist in the
- *         pool's git_odb, or if the commit is present but is
- *         too malformed to be parsed successfully.
- */
-GIT_EXTERN(git_commit *) git_commit_parse(git_revpool *pool, const git_oid *id);
+GIT_EXTERN(git_commit *) git_commit_lookup(git_repository *repo, const git_oid *id);
 
 /**
  * Get the id of a commit.
diff --git a/src/git/common.h b/src/git/common.h
index 09972aade..b43f4ee01 100644
--- a/src/git/common.h
+++ b/src/git/common.h
@@ -85,8 +85,14 @@
 
 GIT_BEGIN_DECL
 
-/** A revision traversal pool. */
-typedef struct git_revpool git_revpool;
+/** 
+ * Representation of an existing git repository,
+ * including all its object contents 
+ */
+typedef struct git_repository git_repository;
+
+/* Representation of a generic object in a repository */
+typedef struct git_repository_object git_repository_object;
 
 /** Parsed representation of a person */
 typedef struct git_person {
diff --git a/src/git/odb.h b/src/git/odb.h
index 58b932645..5d105ba70 100644
--- a/src/git/odb.h
+++ b/src/git/odb.h
@@ -35,6 +35,7 @@ GIT_EXTERN(void) git_odb_close(git_odb *db);
 
 /** Basic type (loose or packed) of any Git object. */
 typedef enum {
+	GIT_OBJ_ANY = -2,		/**< Object can be any of the following */
 	GIT_OBJ_BAD = -1,       /**< Object is invalid. */
 	GIT_OBJ__EXT1 = 0,      /**< Reserved for future use. */
 	GIT_OBJ_COMMIT = 1,     /**< A commit object. */
diff --git a/src/git/repository.h b/src/git/repository.h
new file mode 100644
index 000000000..3b6981d50
--- /dev/null
+++ b/src/git/repository.h
@@ -0,0 +1,60 @@
+#ifndef INCLUDE_git_repository_h__
+#define INCLUDE_git_repository_h__
+
+#include "common.h"
+#include "odb.h"
+#include "commit.h"
+
+/**
+ * @file git/repository.h
+ * @brief Git revision object management routines
+ * @defgroup git_repository Git revision object management routines
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * Allocate a new repository object.
+ *
+ * TODO: specify the repository's path instead
+ * of its object database
+ *
+ * @param odb an existing object database to back the repo
+ * @return the new repository handle; NULL on error 
+ */
+GIT_EXTERN(git_repository *) git_repository_alloc(git_odb *odb);
+
+
+/**
+ * Lookup a reference to one of the objects in the repostory.
+ * 
+ * The generated reference is owned by the repository and
+ * should not be freed by the user.
+ * The generated reference should be cast back to the
+ * expected type; e.g.
+ *
+ *	git_commit *c = (git_commit *)
+ *		git_repository_lookup(repo, id, GIT_OBJ_COMMIT);
+ *
+ * The 'type' parameter must match the type of the object
+ * in the odb; the method will fail otherwise.
+ * The special value 'GIT_OBJ_ANY' may be passed to let
+ * the method guess the object's type.
+ *
+ * @param repo the repository to look up the object
+ * @param id the unique identifier for the object
+ * @param type the type of the object
+ * @return a reference to the object
+ */
+GIT_EXTERN(git_repository_object *) git_repository_lookup(git_repository *repo, const git_oid *id, git_otype type);
+
+/**
+ * Free a previously allocated repository
+ * @param repo repository handle to close. If NULL nothing occurs.
+ */
+GIT_EXTERN(void) git_repository_free(git_repository *repo);
+
+/** @} */
+GIT_END_DECL
+#endif
diff --git a/src/git/revwalk.h b/src/git/revwalk.h
index 7aa92d44a..842503dea 100644
--- a/src/git/revwalk.h
+++ b/src/git/revwalk.h
@@ -15,87 +15,87 @@
 GIT_BEGIN_DECL
 
 /**
- * Sort the revpool contents in no particular ordering;
+ * Sort the repository contents in no particular ordering;
  * this sorting is arbritary, implementation-specific
  * and subject to change at any time.
- * This is the default sorting for new revision pools.
+ * This is the default sorting for new walkers.
  */
-#define GIT_RPSORT_NONE         (0)
+#define GIT_SORT_NONE         (0)
 
 /**
- * Sort the revpool contents in topological order
+ * Sort the repository contents in topological order
  * (parents before children); this sorting mode
  * can be combined with time sorting.
  */
-#define GIT_RPSORT_TOPOLOGICAL  (1 << 0)
+#define GIT_SORT_TOPOLOGICAL  (1 << 0)
 
 /**
- * Sort the revpool contents by commit time;
+ * Sort the repository contents by commit time;
  * this sorting mode can be combined with
  * topological sorting.
  */
-#define GIT_RPSORT_TIME         (1 << 1)
+#define GIT_SORT_TIME         (1 << 1)
 
 /**
- * Iterate through the revpool contents in reverse
+ * Iterate through the repository contents in reverse
  * order; this sorting mode can be combined with
  * any of the above.
  */
-#define GIT_RPSORT_REVERSE      (1 << 2)
+#define GIT_SORT_REVERSE      (1 << 2)
+
+typedef struct git_revwalk git_revwalk;
 
 /**
- * Allocate a new revision traversal pool.
- *
- * The configuration is copied during allocation.  Changes
- * to the configuration after allocation do not affect the pool
- * returned by this function.  Callers may safely free the
- * passed configuration after the function completes.
+ * Allocate a new revision walker to iterate through a repo.
  *
- * @param db the database objects are read from.
- * @return the new traversal handle; NULL if memory is exhausted.
+ * @param repo the repo to walk through
+ * @return the new walker handle; NULL if memory is exhausted.
  */
-GIT_EXTERN(git_revpool *) gitrp_alloc(git_odb *db);
+GIT_EXTERN(git_revwalk *) git_revwalk_alloc(git_repository *repo);
 
 /**
- * Reset the traversal machinary for reuse.
- * @param pool traversal handle to reset.
+ * Reset the walking machinary for reuse.
+ * @param walker handle to reset.
  */
-GIT_EXTERN(void) gitrp_reset(git_revpool *pool);
+GIT_EXTERN(void) git_revwalk_reset(git_revwalk *walker);
 
 /**
- * Mark an object to start traversal from.
- * @param pool the pool being used for the traversal.
+ * Mark a commit to start traversal from.
+ * The commit object must belong to the repo which is being walked through.
+ *
+ * @param walker the walker being used for the traversal.
  * @param commit the commit to start from.
  */
-GIT_EXTERN(int) gitrp_push(git_revpool *pool, git_commit *commit);
+GIT_EXTERN(int) git_revwalk_push(git_revwalk *walk, git_commit *commit);
 
 /**
  * Mark a commit (and its ancestors) uninteresting for the output.
- * @param pool the pool being used for the traversal.
+ * @param walker the walker being used for the traversal.
  * @param commit the commit that will be ignored during the traversal
  */
-GIT_EXTERN(int) gitrp_hide(git_revpool *pool, git_commit *commit);
+GIT_EXTERN(int) git_revwalk_hide(git_revwalk *walk, git_commit *commit);
 
 /**
  * Get the next commit from the revision traversal.
- * @param pool the pool to pop the commit from.
+ * @param walk the walker to pop the commit from.
  * @return next commit; NULL if there is no more output.
  */
-GIT_EXTERN(git_commit *) gitrp_next(git_revpool *pool);
+GIT_EXTERN(git_commit *) git_revwalk_next(git_revwalk *walk);
 
 /**
  * Change the sorting mode when iterating through the
- * revision pool's contents.
- * @param pool the pool being used for the traversal.
+ * repository's contents.
+ * Changing the sorting mode resets the walker.
+ * @param walk the walker being used for the traversal.
  * @param sort_mode combination of GIT_RPSORT_XXX flags
  */
-GIT_EXTERN(void) gitrp_sorting(git_revpool *pool, unsigned int sort_mode);
+GIT_EXTERN(void) git_revwalk_sorting(git_revwalk *walk, unsigned int sort_mode);
 
 /**
  * Free a revwalk previously allocated.
- * @param pool traversal handle to close.  If NULL nothing occurs.
+ * @param walk traversal handle to close.  If NULL nothing occurs.
  */
-GIT_EXTERN(void) gitrp_free(git_revpool *pool);
+GIT_EXTERN(void) git_revwalk_free(git_revwalk *walk);
 
 /** @} */
 GIT_END_DECL
diff --git a/src/git/tag.h b/src/git/tag.h
index 509d2f047..d94083b11 100644
--- a/src/git/tag.h
+++ b/src/git/tag.h
@@ -4,6 +4,7 @@
 #include "common.h"
 #include "oid.h"
 #include "tree.h"
+#include "repository.h"
 
 /**
  * @file git/tag.h
@@ -18,29 +19,15 @@ GIT_BEGIN_DECL
 typedef struct git_tag git_tag;
 
 /**
- * Locate a reference to a tag without loading it.
+ * Lookup a tag object from the repository.
  * The generated tag object is owned by the revision
- * pool and shall not be freed by the user.
+ * repo and shall not be freed by the user.
  *
- * @param pool the pool to use when locating the tag.
+ * @param repo the repo to use when locating the tag.
  * @param id identity of the tag to locate.
  * @return the tag; NULL if the tag could not be created
  */
-GIT_EXTERN(git_tag *) git_tag_lookup(git_revpool *pool, const git_oid *id);
-
-/**
- * Locate a reference to a tag, and try to load and parse it it from
- * the object cache or the object database.
- * The generated tag object is owned by the revision
- * pool and shall not be freed by the user.
- *
- * @param pool the pool to use when parsing/caching the tag.
- * @param id identity of the tag to locate.  
- * @return the tag; NULL if the tag does not exist in the
- *         pool's git_odb, or if the tag is present but is
- *         too malformed to be parsed successfully.
- */
-GIT_EXTERN(git_tag *) git_tag_parse(git_revpool *pool, const git_oid *id);
+GIT_EXTERN(git_tag *) git_tag_lookup(git_repository *repo, const git_oid *id);
 
 /**
  * Get the id of a tag.
diff --git a/src/git/tree.h b/src/git/tree.h
index 9a4973ba6..95b233009 100644
--- a/src/git/tree.h
+++ b/src/git/tree.h
@@ -3,6 +3,7 @@
 
 #include "common.h"
 #include "oid.h"
+#include "repository.h"
 
 /**
  * @file git/tree.h
@@ -17,27 +18,15 @@ GIT_BEGIN_DECL
 typedef struct git_tree git_tree;
 
 /**
- * Locate a reference to a tree without loading it.
+ * Lookup a tree object from the repository.
  * The generated tree object is owned by the revision
- * pool and shall not be freed by the user.
+ * repo and shall not be freed by the user.
  *
- * @param pool the pool to use when locating the tree.
+ * @param repo the repo to use when locating the tree.
  * @param id identity of the tree to locate.
  * @return the tree; NULL if the tree could not be created
  */
-GIT_EXTERN(git_tree *) git_tree_lookup(git_revpool *pool, const git_oid *id);
-
-/**
- * Locate a reference to a tree object and parse its
- * contents.
- * The generated tree object is owned by the revision
- * pool and shall not be freed by the user.
- *
- * @param pool the pool to use when locating the tree.
- * @param id identity of the tree to locate.
- * @return the tree; NULL if the tree could not be created
- */
-GIT_EXTERN(git_tree *) git_tree_parse(git_revpool *pool, const git_oid *id);
+GIT_EXTERN(git_tree *) git_tree_lookup(git_repository *repo, const git_oid *id);
 
 /**
  * Get the id of a tree.