/*
* 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_sys_git_odb_mempack_h__
#define INCLUDE_sys_git_odb_mempack_h__
#include "git2/common.h"
#include "git2/types.h"
#include "git2/oid.h"
#include "git2/odb.h"
/**
* @file git2/sys/mempack.h
* @brief Custom ODB backend that permits packing objects in-memory
* @defgroup git_backend Git custom backend APIs
* @ingroup Git
* @{
*/
GIT_BEGIN_DECL
/**
* Instantiate a new mempack backend.
*
* The backend must be added to an existing ODB with the highest
* priority.
*
* git_mempack_new(&mempacker);
* git_repository_odb(&odb, repository);
* git_odb_add_backend(odb, mempacker, 999);
*
* Once the backend has been loaded, all writes to the ODB will
* instead be queued in memory, and can be finalized with
* `git_mempack_dump`.
*
* Subsequent reads will also be served from the in-memory store
* to ensure consistency, until the memory store is dumped.
*
* @param out Poiter where to store the ODB backend
* @return 0 on success; error code otherwise
*/
int git_mempack_new(git_odb_backend **out);
/**
* Dump all the queued in-memory writes to a packfile.
*
* The contents of the packfile will be stored in the given buffer.
* It is the caller's responsibility to ensure that the generated
* packfile is available to the repository (e.g. by writing it
* to disk, or doing something crazy like distributing it across
* several copies of the repository over a network).
*
* Once the generated packfile is available to the repository,
* call `git_mempack_reset` to cleanup the memory store.
*
* Calling `git_mempack_reset` before the packfile has been
* written to disk will result in an inconsistent repository
* (the objects in the memory store won't be accessible).
*
* @param pack Buffer where to store the raw packfile
* @param repo The active repository where the backend is loaded
* @param backend The mempack backend
* @return 0 on success; error code otherwise
*/
int git_mempack_dump(git_buf *pack, git_repository *repo, git_odb_backend *backend);
/**
* Reset the memory packer by clearing all the queued objects.
*
* This assumes that `git_mempack_dump` has been called before to
* store all the queued objects into a single packfile.
*
* Alternatively, call `reset` without a previous dump to "undo"
* all the recently written objects, giving transaction-like
* semantics to the Git repository.
*
* @param backend The mempack backend
*/
void git_mempack_reset(git_odb_backend *backend);
GIT_END_DECL
#endif
