Move odb_backend implementors stuff into git2/sys

This moves some of the odb_backend stuff that is related to the
internals of an odb_backend implementation into include/git2/sys.

Some of the stuff related to streaming I left in include/git2
because it seemed like it would be reasonably needed by a normal
user who wanted to stream objects into and out of the ODB.

Also, I added APIs for traversing the list of backends so that
some of the tests would not need to access ODB internals.

Author: arrbee

include/git2/indexer.h

@@ -8,31 +8,11 @@
 #define _INCLUDE_git_indexer_h__
 
 #include "common.h"
+#include "types.h"
 #include "oid.h"
 
 GIT_BEGIN_DECL
 
-/**
- * This is passed as the first argument to the callback to allow the
- * user to see the progress.
- */
-typedef struct git_transfer_progress {
-	unsigned int total_objects;
-	unsigned int indexed_objects;
-	unsigned int received_objects;
-	size_t received_bytes;
-} git_transfer_progress;
-
-
-/**
- * Type for progress callbacks during indexing.  Return a value less than zero
- * to cancel the transfer.
- *
- * @param stats Structure containing information about the state of the transfer
- * @param payload Payload provided by caller
- */
-typedef int (*git_transfer_progress_callback)(const git_transfer_progress *stats, void *payload);
-
 typedef struct git_indexer_stream git_indexer_stream;
 
 /**

include/git2/odb.h

@@ -10,8 +10,6 @@
 #include "common.h"
 #include "types.h"
 #include "oid.h"
-#include "odb_backend.h"
-#include "indexer.h"
 
 /**
  * @file git2/odb.h
@@ -22,6 +20,11 @@
  */
 GIT_BEGIN_DECL
 
+/**
+ * Function type for callbacks from git_odb_foreach.
+ */
+typedef int (*git_odb_foreach_cb)(const git_oid *id, void *payload);
+
 /**
  * Create a new object database with no backends.
  *
@@ -52,42 +55,6 @@ GIT_EXTERN(int) git_odb_new(git_odb **out);
  */
 GIT_EXTERN(int) git_odb_open(git_odb **out, const char *objects_dir);
 
-/**
- * Add a custom backend to an existing Object DB
- *
- * The backends are checked in relative ordering, based on the
- * value of the `priority` parameter.
- *
- * Read <odb_backends.h> for more information.
- *
- * @param odb database to add the backend to
- * @param backend pointer to a git_odb_backend instance
- * @param priority Value for ordering the backends queue
- * @return 0 on success; error code otherwise
- */
-GIT_EXTERN(int) git_odb_add_backend(git_odb *odb, git_odb_backend *backend, int priority);
-
-/**
- * Add a custom backend to an existing Object DB; this
- * backend will work as an alternate.
- *
- * Alternate backends are always checked for objects *after*
- * all the main backends have been exhausted.
- *
- * The backends are checked in relative ordering, based on the
- * value of the `priority` parameter.
- *
- * Writing is disabled on alternate backends.
- *
- * Read <odb_backends.h> for more information.
- *
- * @param odb database to add the backend to
- * @param backend pointer to a git_odb_backend instance
- * @param priority Value for ordering the backends queue
- * @return 0 on success; error code otherwise
- */
-GIT_EXTERN(int) git_odb_add_alternate(git_odb *odb, git_odb_backend *backend, int priority);
-
 /**
  * Add an on-disk alternate to an existing Object DB.
  *
@@ -406,6 +373,60 @@ GIT_EXTERN(size_t) git_odb_object_size(git_odb_object *object);
  */
 GIT_EXTERN(git_otype) git_odb_object_type(git_odb_object *object);
 
+/**
+ * Add a custom backend to an existing Object DB
+ *
+ * The backends are checked in relative ordering, based on the
+ * value of the `priority` parameter.
+ *
+ * Read <odb_backends.h> for more information.
+ *
+ * @param odb database to add the backend to
+ * @param backend pointer to a git_odb_backend instance
+ * @param priority Value for ordering the backends queue
+ * @return 0 on success; error code otherwise
+ */
+GIT_EXTERN(int) git_odb_add_backend(git_odb *odb, git_odb_backend *backend, int priority);
+
+/**
+ * Add a custom backend to an existing Object DB; this
+ * backend will work as an alternate.
+ *
+ * Alternate backends are always checked for objects *after*
+ * all the main backends have been exhausted.
+ *
+ * The backends are checked in relative ordering, based on the
+ * value of the `priority` parameter.
+ *
+ * Writing is disabled on alternate backends.
+ *
+ * Read <odb_backends.h> for more information.
+ *
+ * @param odb database to add the backend to
+ * @param backend pointer to a git_odb_backend instance
+ * @param priority Value for ordering the backends queue
+ * @return 0 on success; error code otherwise
+ */
+GIT_EXTERN(int) git_odb_add_alternate(git_odb *odb, git_odb_backend *backend, int priority);
+
+/**
+ * Get the number of ODB backend objects
+ *
+ * @param odb object database
+ * @return number of backends in the ODB
+ */
+GIT_EXTERN(size_t) git_odb_num_backends(git_odb *odb);
+
+/**
+ * Lookup an ODB backend object by index
+ *
+ * @param out output pointer to ODB backend at pos
+ * @param odb object database
+ * @param pos index into object database backend list
+ * @return 0 on success; GIT_ENOTFOUND if pos is invalid; other errors < 0
+ */
+GIT_EXTERN(int) git_odb_get_backend(git_odb_backend **out, git_odb *odb, size_t pos);
+
 /** @} */
 GIT_END_DECL
 #endif

include/git2/odb_backend.h

@@ -7,106 +7,24 @@
 #ifndef INCLUDE_git_odb_backend_h__
 #define INCLUDE_git_odb_backend_h__
 
-#include "common.h"
-#include "types.h"
-#include "oid.h"
-#include "indexer.h"
+#include "git2/common.h"
+#include "git2/types.h"
 
 /**
  * @file git2/backend.h
  * @brief Git custom backend functions
- * @defgroup git_backend Git custom backend API
+ * @defgroup git_odb Git object database routines
  * @ingroup Git
  * @{
  */
 GIT_BEGIN_DECL
 
-struct git_odb_stream;
-struct git_odb_writepack;
-
-/**
- * Function type for callbacks from git_odb_foreach.
- */
-typedef int (*git_odb_foreach_cb)(const git_oid *id, void *payload);
-
 /**
- * An instance for a custom backend
+ * Constructors for in-box ODB backends.
  */
-struct git_odb_backend {
-	unsigned int version;
-	git_odb *odb;
-
-	/* read and read_prefix each return to libgit2 a buffer which
-	 * will be freed later. The buffer should be allocated using
-	 * the function git_odb_backend_malloc to ensure that it can
-	 * be safely freed later. */
-	int (* read)(
-			void **, size_t *, git_otype *,
-			struct git_odb_backend *,
-			const git_oid *);
-
-	/* To find a unique object given a prefix
-	 * of its oid.
-	 * The oid given must be so that the
-	 * remaining (GIT_OID_HEXSZ - len)*4 bits
-	 * are 0s.
-	 */
-	int (* read_prefix)(
-			git_oid *,
-			void **, size_t *, git_otype *,
-			struct git_odb_backend *,
-			const git_oid *,
-			size_t);
-
-	int (* read_header)(
-			size_t *, git_otype *,
-			struct git_odb_backend *,
-			const git_oid *);
-
-	/* The writer may assume that the object
-	 * has already been hashed and is passed
-	 * in the first parameter.
-	 */
-	int (* write)(
-			git_oid *,
-			struct git_odb_backend *,
-			const void *,
-			size_t,
-			git_otype);
-
-	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 *);
-
-	int (* exists)(
-			struct git_odb_backend *,
-			const git_oid *);
-
-	int (* refresh)(struct git_odb_backend *);
-
-	int (* foreach)(
-			struct git_odb_backend *,
-			git_odb_foreach_cb cb,
-			void *payload);
-
-	int (* writepack)(
-			struct git_odb_writepack **,
-			struct git_odb_backend *,
-			git_transfer_progress_callback progress_cb,
-			void *progress_payload);
-
-	void (* free)(struct git_odb_backend *);
-};
-
-#define GIT_ODB_BACKEND_VERSION 1
-#define GIT_ODB_BACKEND_INIT {GIT_ODB_BACKEND_VERSION}
+GIT_EXTERN(int) git_odb_backend_pack(git_odb_backend **out, const char *objects_dir);
+GIT_EXTERN(int) git_odb_backend_loose(git_odb_backend **out, const char *objects_dir, int compression_level, int do_fsync);
+GIT_EXTERN(int) git_odb_backend_one_pack(git_odb_backend **out, const char *index_file);
 
 /** Streaming mode */
 enum {
@@ -117,33 +35,24 @@ enum {
 
 /** A stream to read/write from a backend */
 struct git_odb_stream {
-	struct git_odb_backend *backend;
+	git_odb_backend *backend;
 	unsigned int mode;
 
-	int (*read)(struct git_odb_stream *stream, char *buffer, size_t len);
-	int (*write)(struct git_odb_stream *stream, const char *buffer, size_t len);
-	int (*finalize_write)(git_oid *oid_p, struct git_odb_stream *stream);
-	void (*free)(struct git_odb_stream *stream);
+	int (*read)(git_odb_stream *stream, char *buffer, size_t len);
+	int (*write)(git_odb_stream *stream, const char *buffer, size_t len);
+	int (*finalize_write)(git_oid *oid_p, git_odb_stream *stream);
+	void (*free)(git_odb_stream *stream);
 };
 
 /** A stream to write a pack file to the ODB */
 struct git_odb_writepack {
-	struct git_odb_backend *backend;
+	git_odb_backend *backend;
 
-	int (*add)(struct git_odb_writepack *writepack, const void *data, size_t size, git_transfer_progress *stats);
-	int (*commit)(struct git_odb_writepack *writepack, git_transfer_progress *stats);
-	void (*free)(struct git_odb_writepack *writepack);
+	int (*add)(git_odb_writepack *writepack, const void *data, size_t size, git_transfer_progress *stats);
+	int (*commit)(git_odb_writepack *writepack, git_transfer_progress *stats);
+	void (*free)(git_odb_writepack *writepack);
 };
 
-GIT_EXTERN(void *) git_odb_backend_malloc(git_odb_backend *backend, size_t len);
-
-/**
- * Constructors for in-box ODB backends.
- */
-GIT_EXTERN(int) git_odb_backend_pack(git_odb_backend **out, const char *objects_dir);
-GIT_EXTERN(int) git_odb_backend_loose(git_odb_backend **out, const char *objects_dir, int compression_level, int do_fsync);
-GIT_EXTERN(int) git_odb_backend_one_pack(git_odb_backend **out, const char *index_file);
-
 GIT_END_DECL
 
 #endif

include/git2/sys/config.h

@@ -4,8 +4,8 @@
  * This file is part of libgit2, distributed under the GNU GPL v2 with
  * a Linking Exception. For full terms see the included COPYING file.
  */
-#ifndef INCLUDE_git_sys_config_h__
-#define INCLUDE_git_sys_config_h__
+#ifndef INCLUDE_sys_git_config_backend_h__
+#define INCLUDE_sys_git_config_backend_h__
 
 #include "git2/common.h"
 #include "git2/types.h"
@@ -14,6 +14,7 @@
 /**
  * @file git2/sys/config.h
  * @brief Git config backend routines
+ * @defgroup git_backend Git custom backend APIs
  * @ingroup Git
  * @{
  */