I broke your bindings

Hey. Apologies in advance -- I broke your bindings.

This is a major commit that includes a long-overdue redesign of the
whole object-database structure. This is expected to be the last major
external API redesign of the library until the first non-alpha release.

Please get your bindings up to date with these changes. They will be
included in the next minor release. Sorry again!

Major features include:

	- Real caching and refcounting on parsed objects
	- Real caching and refcounting on objects read from the ODB
	- Streaming writes & reads from the ODB
	- Single-method writes for all object types
	- The external API is now partially thread-safe

The speed increases are significant in all aspects, specially when
reading an object several times from the ODB (revwalking) and when
writing big objects to the ODB.

Here's a full changelog for the external API:

blob.h
------

	- Remove `git_blob_new`
	- Remove `git_blob_set_rawcontent`
	- Remove `git_blob_set_rawcontent_fromfile`
	- Rename `git_blob_writefile` -> `git_blob_create_fromfile`
	- Change `git_blob_create_fromfile`:
		The `path` argument is now relative to the repository's working dir
	- Add `git_blob_create_frombuffer`

commit.h
--------

	- Remove `git_commit_new`
	- Remove `git_commit_add_parent`
	- Remove `git_commit_set_message`
	- Remove `git_commit_set_committer`
	- Remove `git_commit_set_author`
	- Remove `git_commit_set_tree`

	- Add `git_commit_create`
	- Add `git_commit_create_v`
	- Add `git_commit_create_o`
	- Add `git_commit_create_ov`

tag.h
-----

	- Remove `git_tag_new`
	- Remove `git_tag_set_target`
	- Remove `git_tag_set_name`
	- Remove `git_tag_set_tagger`
	- Remove `git_tag_set_message`

	- Add `git_tag_create`
	- Add `git_tag_create_o`

tree.h
------

	- Change `git_tree_entry_2object`:
		New signature is `(git_object **object_out, git_repository *repo, git_tree_entry *entry)`

	- Remove `git_tree_new`
	- Remove `git_tree_add_entry`
	- Remove `git_tree_remove_entry_byindex`
	- Remove `git_tree_remove_entry_byname`
	- Remove `git_tree_clearentries`
	- Remove `git_tree_entry_set_id`
	- Remove `git_tree_entry_set_name`
	- Remove `git_tree_entry_set_attributes`

object.h
------------

	- Remove `git_object_new
	- Remove `git_object_write`

	- Change `git_object_close`:
		This method is now *mandatory*. Not closing an object causes a
		memory leak.

odb.h
-----

	- Remove type `git_rawobj`
	- Remove `git_rawobj_close`
	- Rename `git_rawobj_hash` -> `git_odb_hash`
	- Change `git_odb_hash`:
		New signature is `(git_oid *id, const void *data, size_t len, git_otype type)`

	- Add type `git_odb_object`
	- Add `git_odb_object_close`

	- Change `git_odb_read`:
		New signature is `(git_odb_object **out, git_odb *db, const git_oid *id)`
	- Change `git_odb_read_header`:
		New signature is `(size_t *len_p, git_otype *type_p, git_odb *db, const git_oid *id)`
	- Remove `git_odb_write`
	- Add `git_odb_open_wstream`
	- Add `git_odb_open_rstream`

odb_backend.h
-------------

	- Change type `git_odb_backend`:
		New internal signatures are as follows

			int (* read)(void **, size_t *, git_otype *, struct git_odb_backend *, const git_oid *)
			int (* read_header)(size_t *, git_otype *, struct git_odb_backend *, const git_oid *)
			int (* writestream)(struct git_odb_stream **, struct git_odb_backend *, size_t, git_otype)
			int (* readstream)( struct git_odb_stream **, struct git_odb_backend *, const git_oid *)

	- Add type `git_odb_stream`
	- Add enum `git_odb_streammode`

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

1 files changed, 85 insertions, 46 deletions

diff --git a/include/git2/odb.h b/include/git2/odb.h
index 0d285897c..8926b446c 100644
--- a/include/git2/odb.h
+++ b/include/git2/odb.h
@@ -28,6 +28,7 @@
 #include "common.h"
 #include "types.h"
 #include "oid.h"
+#include "odb_backend.h"
 
 /**
  * @file git2/odb.h
@@ -100,61 +101,49 @@ GIT_EXTERN(int) git_odb_add_alternate(git_odb *odb, git_odb_backend *backend, in
 
 /**
  * Close an open object database.
+ *
  * @param db database pointer to close.  If NULL no action is taken.
  */
 GIT_EXTERN(void) git_odb_close(git_odb *db);
 
-/** An object read from the database. */
-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;
-
 /**
  * Read an object from the database.
  *
- * If GIT_ENOTFOUND then out->data is set to NULL.
+ * This method queries all avaiable ODB backends
+ * trying to read the given OID.
+ *
+ * The returned object is reference counted and
+ * internally cached, so it should be closed
+ * by the user once it's no longer in use.
  *
- * @param out object descriptor to populate upon reading.
+ * @param out pointer where to store the read object
  * @param db database to search for the object in.
  * @param id identity of the object to read.
  * @return
  * - GIT_SUCCESS if the object was read;
  * - GIT_ENOTFOUND if the object is not in the database.
  */
-GIT_EXTERN(int) git_odb_read(git_rawobj *out, git_odb *db, const git_oid *id);
+GIT_EXTERN(int) git_odb_read(git_odb_object **out, git_odb *db, const git_oid *id);
 
 /**
  * Read the header of an object from the database, without
  * reading its full contents.
  *
- * Only the 'type' and 'len' fields of the git_rawobj structure
- * are filled. The 'data' pointer will always be NULL.
+ * The header includes the length and the type of an object.
  *
- * The raw object pointed by 'out' doesn't need to be manually
- * closed with git_rawobj_close().
+ * Note that most backends do not support reading only the header
+ * of an object, so the whole object will be read and then the
+ * header will be returned.
  *
- * @param out object descriptor to populate upon reading.
+ * @param len_p pointer where to store the length
+ * @param type_p pointer where to store the type
  * @param db database to search for the object in.
  * @param id identity of the object to read.
  * @return
  * - GIT_SUCCESS if the object was read;
  * - GIT_ENOTFOUND if the object is not in the database.
  */
-GIT_EXTERN(int) git_odb_read_header(git_rawobj *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_rawobj *obj);
+GIT_EXTERN(int) git_odb_read_header(size_t *len_p, git_otype *type_p, git_odb *db, const git_oid *id);
 
 /**
  * Determine if the given object can be found in the object database.
@@ -162,39 +151,89 @@ GIT_EXTERN(int) git_odb_write(git_oid *id, git_odb *db, git_rawobj *obj);
  * @param db database to be searched for the given object.
  * @param id the object to search for.
  * @return
- * - true, if the object was found
- * - false, otherwise
+ * - 1, if the object was found
+ * - 0, otherwise
  */
 GIT_EXTERN(int) git_odb_exists(git_odb *db, const git_oid *id);
 
+/**
+ * Open a stream to write an object into the ODB
+ *
+ * The type and final length of the object must be specified
+ * when opening the stream.
+ *
+ * The returned stream will be of type `GIT_STREAM_WRONLY` and
+ * will have the following methods:
+ *	
+ *		- stream->write: write `n` bytes into the stream
+ *		- stream->finalize_write: close the stream and store the object in
+ *			the odb
+ *		- stream->free: free the stream
+ * 
+ * The streaming write won't be effective until `stream->finalize_write`
+ * is called and returns without an error
+ *
+ * The stream must always be free'd or will leak memory.
+ *
+ * @see git_odb_stream
+ *
+ * @param stream pointer where to store the stream
+ * @param db object database where the stream will write
+ * @param size final size of the object that will be written
+ * @para type type of the object that will be written
+ * @return 0 if the stream was created; error code otherwise
+ */
+GIT_EXTERN(int) git_odb_open_wstream(git_odb_stream **stream, git_odb *db, size_t size, git_otype type);
 
-
-
+/**
+ * Open a stream to read an object from the ODB
+ *
+ * Note that most backends do *not* support streaming reads
+ * because they store their objects as compressed/delta'ed blobs.
+ *
+ * It's recommended to use `git_odb_read` instead, which is
+ * assured to work on all backends.
+ *
+ * The returned stream will be of type `GIT_STREAM_RDONLY` and
+ * will have the following methods:
+ *	
+ *		- stream->read: read `n` bytes from the stream
+ *		- stream->free: free the stream
+ *
+ * The stream must always be free'd or will leak memory.
+ *
+ * @see git_odb_stream
+ *
+ * @param stream pointer where to store the stream
+ * @param db object database where the stream will read from
+ * @param oid oid of the object the stream will read from
+ * @return 0 if the stream was created; error code otherwise
+ */
+GIT_EXTERN(int) git_odb_open_rstream(git_odb_stream **stream, git_odb *db, const git_oid *oid);
 
 /**
- * Determine the object-ID (sha1 hash) of the given git_rawobj.
+ * Determine the object-ID (sha1 hash) of a data buffer
  *
- * The input obj must be a valid loose object type and the data
- * pointer must not be NULL, unless the len field is also zero.
+ * The resulting SHA-1 OID will the itentifier for the data
+ * buffer as if the data buffer it were to written to the ODB.
  *
  * @param id the resulting object-ID.
- * @param obj the object whose hash is to be determined.
- * @return
- * - GIT_SUCCESS if the object-ID was correctly determined.
- * - GIT_ERROR if the given object is malformed.
+ * @param data data to hash
+ * @param len size of the data
+ * @param type of the data to hash
+ * @return 0 on success; error code otherwise
  */
-GIT_EXTERN(int) git_rawobj_hash(git_oid *id, git_rawobj *obj);
+GIT_EXTERN(int) git_odb_hash(git_oid *id, const void *data, size_t len, git_otype type);
 
 /**
- * Release all memory used by the obj structure.
- *
- * As a result of this call, obj->data will be set to NULL.
+ * Close an ODB object
  *
- * If obj->data is already NULL, nothing happens.
+ * This method must always be called once a `git_odb_object` is no
+ * longer needed, otherwise memory will leak.
  *
- * @param obj object descriptor to free.
+ * @param object object to close
  */
-GIT_EXTERN(void) git_rawobj_close(git_rawobj *obj);
+GIT_EXTERN(void) git_odb_object_close(git_odb_object *object);
 
 /** @} */
 GIT_END_DECL