/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* 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_odb_backend_h__
#define INCLUDE_git_odb_backend_h__
#include "git2/common.h"
#include "git2/types.h"
/**
* @file git2/backend.h
* @brief Git custom backend functions
* @defgroup git_odb Git object database routines
* @ingroup Git
* @{
*/
GIT_BEGIN_DECL
/*
* Constructors for in-box ODB backends.
*/
/**
* Create a backend for the packfiles.
*
* @param out location to store the odb backend pointer
* @param objects_dir the Git repository's objects directory
*
* @return 0 or an error code
*/
GIT_EXTERN(int) git_odb_backend_pack(git_odb_backend **out, const char *objects_dir);
/**
* Create a backend for loose objects
*
* @param out location to store the odb backend pointer
* @param objects_dir the Git repository's objects directory
* @param compression_level zlib compression level to use
* @param do_fsync whether to do an fsync() after writing (currently ignored)
*
* @return 0 or an error code
*/
GIT_EXTERN(int) git_odb_backend_loose(git_odb_backend **out, const char *objects_dir, int compression_level, int do_fsync);
/**
* Create a backend out of a single packfile
*
* This can be useful for inspecting the contents of a single
* packfile.
*
* @param out location to store the odb backend pointer
* @param index_file path to the packfile's .idx file
*
* @return 0 or an error code
*/
GIT_EXTERN(int) git_odb_backend_one_pack(git_odb_backend **out, const char *index_file);
/** Streaming mode */
typedef enum {
GIT_STREAM_RDONLY = (1 << 1),
GIT_STREAM_WRONLY = (1 << 2),
GIT_STREAM_RW = (GIT_STREAM_RDONLY | GIT_STREAM_WRONLY),
} git_odb_stream_t;
/**
* A stream to read/write from a backend.
*
* This represents a stream of data being written to or read from a
* backend. When writing, the frontend functions take care of
* calculating the object's id and all `finalize_write` needs to do is
* store the object with the id it is passed.
*/
struct git_odb_stream {
git_odb_backend *backend;
unsigned int mode;
void *hash_ctx;
size_t declared_size;
size_t received_bytes;
/**
* Write at most `len` bytes into `buffer` and advance the stream.
*/
int (*read)(git_odb_stream *stream, char *buffer, size_t len);
/**
* Write `len` bytes from `buffer` into the stream.
*/
int (*write)(git_odb_stream *stream, const char *buffer, size_t len);
/**
* Store the contents of the stream as an object with the id
* specified in `oid`.
*
* This method might not be invoked if:
* - an error occurs earlier with the `write` callback,
* - the object referred to by `oid` already exists in any backend, or
* - the final number of received bytes differs from the size declared
* with `git_odb_open_wstream()`
*/
int (*finalize_write)(git_odb_stream *stream, const git_oid *oid);
/**
* Free the stream's memory.
*
* This method might be called without a call to `finalize_write` if
* an error occurs or if the object is already present in the ODB.
*/
void (*free)(git_odb_stream *stream);
};
/** A stream to write a pack file to the ODB */
struct git_odb_writepack {
git_odb_backend *backend;
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_END_DECL
#endif
