libgit2/include/git2/blob.h

/*
 * Copyright (C) 2009-2012 the libgit2 contributors
 *
 * 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_blob_h__
#define INCLUDE_git_blob_h__

#include "common.h"
#include "types.h"
#include "oid.h"
#include "object.h"

/**
 * @file git2/blob.h
 * @brief Git blob load and write routines
 * @defgroup git_blob Git blob load and write routines
 * @ingroup Git
 * @{
 */
GIT_BEGIN_DECL

/**
 * Lookup a blob object from a repository.
 *
 * @param blob pointer to the looked up blob
 * @param repo the repo to use when locating the blob.
 * @param id identity of the blob to locate.
 * @return 0 or an error code
 */
GIT_INLINE(int) git_blob_lookup(git_blob **blob, git_repository *repo, const git_oid *id)
{
	return git_object_lookup((git_object **)blob, repo, id, GIT_OBJ_BLOB);
}

/**
 * Lookup a blob object from a repository,
 * given a prefix of its identifier (short id).
 *
 * @see git_object_lookup_prefix
 *
 * @param blob pointer to the looked up blob
 * @param repo the repo to use when locating the blob.
 * @param id identity of the blob to locate.
 * @param len the length of the short identifier
 * @return 0 or an error code
 */
GIT_INLINE(int) git_blob_lookup_prefix(git_blob **blob, git_repository *repo, const git_oid *id, size_t len)
{
	return git_object_lookup_prefix((git_object **)blob, repo, id, len, GIT_OBJ_BLOB);
}

/**
 * Close an open blob
 *
 * This is a wrapper around git_object_free()
 *
 * IMPORTANT:
 * It *is* necessary to call this method when you stop
 * using a blob. Failure to do so will cause a memory leak.
 *
 * @param blob the blob to close
 */

GIT_INLINE(void) git_blob_free(git_blob *blob)
{
	git_object_free((git_object *) blob);
}

/**
 * Get the id of a blob.
 *
 * @param blob a previously loaded blob.
 * @return SHA1 hash for this blob.
 */
GIT_INLINE(const git_oid *) git_blob_id(const git_blob *blob)
{
	return git_object_id((const git_object *)blob);
}


/**
 * Get a read-only buffer with the raw content of a blob.
 *
 * A pointer to the raw content of a blob is returned;
 * this pointer is owned internally by the object and shall
 * not be free'd. The pointer may be invalidated at a later
 * time.
 *
 * @param blob pointer to the blob
 * @return the pointer; NULL if the blob has no contents
 */
GIT_EXTERN(const void *) git_blob_rawcontent(git_blob *blob);

/**
 * Get the size in bytes of the contents of a blob
 *
 * @param blob pointer to the blob
 * @return size on bytes
 */
GIT_EXTERN(git_off_t) git_blob_rawsize(git_blob *blob);

/**
 * Read a file from the working folder of a repository
 * and write it to the Object Database as a loose blob
 *
 * @param id return the id of the written blob
 * @param repo repository where the blob will be written.
 *	this repository cannot be bare
 * @param relative_path file from which the blob will be created,
 *	relative to the repository's working dir
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_blob_create_fromworkdir(git_oid *id, git_repository *repo, const char *relative_path);

/**
 * Read a file from the filesystem and write its content
 * to the Object Database as a loose blob
 *
 * @param id return the id of the written blob
 * @param repo repository where the blob will be written.
 *	this repository can be bare or not
 * @param path file from which the blob will be created
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_blob_create_fromdisk(git_oid *id, git_repository *repo, const char *path);


typedef int (*git_blob_chunk_cb)(char *content, size_t max_length, void *payload);

/**
 * Write a loose blob to the Object Database from a
 * provider of chunks of data.
 *
 * Provided the `hintpath` parameter is filled, its value
 * will help to determine what git filters should be applied
 * to the object before it can be placed to the object database.
 *
 *
 * The implementation of the callback has to respect the
 * following rules:
 *
 *  - `content` will have to be filled by the consumer. The maximum number
 * of bytes that the buffer can accept per call is defined by the
 * `max_length` parameter. Allocation and freeing of the buffer will be taken
 * care of by the function.
 *
 *  - The callback is expected to return the number of bytes
 * that `content` have been filled with.
 *
 *  - When there is no more data to stream, the callback should
 * return 0. This will prevent it from being invoked anymore.
 *
 *  - When an error occurs, the callback should return -1.
 *
 *
 * @param id Return the id of the written blob
 *
 * @param repo repository where the blob will be written.
 * This repository can be bare or not.
 *
 * @param hintpath if not NULL, will help selecting the filters
 * to apply onto the content of the blob to be created.
 *
 * @return GIT_SUCCESS or an error code
 */
GIT_EXTERN(int) git_blob_create_fromchunks(
	git_oid *id,
	git_repository *repo,
	const char *hintpath,
	git_blob_chunk_cb callback,
	void *payload);

/**
 * Write an in-memory buffer to the ODB as a blob
 *
 * @param oid return the oid of the written blob
 * @param repo repository where to blob will be written
 * @param buffer data to be written into the blob
 * @param len length of the data
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_blob_create_frombuffer(git_oid *oid, git_repository *repo, const void *buffer, size_t len);

/** @} */
GIT_END_DECL
#endif