vendor/libgit2-sys/libgit2/include/git2/odb.h - toolchain/rustc - Git at Google

 /*
  * 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_h__
 #define INCLUDE_git_odb_h__

 #include "common.h"
 #include "types.h"
 #include "oid.h"
 #include "oidarray.h"
 #include "indexer.h"

 /**
  * @file git2/odb.h
  * @brief Git object database routines
  * @defgroup git_odb Git object database routines
  * @ingroup Git
  * @{
  */
 GIT_BEGIN_DECL

 /**
  * Function type for callbacks from git_odb_foreach.
  */
 typedef int GIT_CALLBACK(git_odb_foreach_cb)(const git_oid *id, void *payload);

 /**
  * Create a new object database with no backends.
  *
  * Before the ODB can be used for read/writing, a custom database
  * backend must be manually added using `git_odb_add_backend()`
  *
  * @param out location to store the database pointer, if opened.
  *			Set to NULL if the open failed.
  * @return 0 or an error code
  */
 GIT_EXTERN(int) git_odb_new(git_odb **out);

 /**
  * Create a new object database and automatically add
  * the two default backends:
  *
  *	- git_odb_backend_loose: read and write loose object files
  *		from disk, assuming `objects_dir` as the Objects folder
  *
  *	- git_odb_backend_pack: read objects from packfiles,
  *		assuming `objects_dir` as the Objects folder which
  *		contains a 'pack/' folder with the corresponding data
  *
  * @param out location to store the database pointer, if opened.
  *			Set to NULL if the open failed.
  * @param objects_dir path of the backends' "objects" directory.
  * @return 0 or an error code
  */
 GIT_EXTERN(int) git_odb_open(git_odb **out, const char *objects_dir);

 /**
  * Add an on-disk alternate to an existing Object DB.
  *
  * Note that the added path must point to an `objects`, not
  * to a full repository, to use it as an alternate store.
  *
  * Alternate backends are always checked for objects *after*
  * all the main backends have been exhausted.
  *
  * Writing is disabled on alternate backends.
  *
  * @param odb database to add the backend to
  * @param path path to the objects folder for the alternate
  * @return 0 on success; error code otherwise
  */
 GIT_EXTERN(int) git_odb_add_disk_alternate(git_odb *odb, const char *path);

 /**
  * Close an open object database.
  *
  * @param db database pointer to close. If NULL no action is taken.
  */
 GIT_EXTERN(void) git_odb_free(git_odb *db);

 /**
  * Read an object from the database.
  *
  * This method queries all available 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 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
  * - 0 if the object was read;
  * - GIT_ENOTFOUND if the object is not in the database.
  */
 GIT_EXTERN(int) git_odb_read(git_odb_object **out, git_odb *db, const git_oid *id);

 /**
  * Read an object from the database, given a prefix
  * of its identifier.
  *
  * This method queries all available ODB backends
  * trying to match the 'len' first hexadecimal
  * characters of the 'short_id'.
  * The remaining (GIT_OID_HEXSZ-len)*4 bits of
  * 'short_id' must be 0s.
  * 'len' must be at least GIT_OID_MINPREFIXLEN,
  * and the prefix must be long enough to identify
  * a unique object in all the backends; the
  * method will fail otherwise.
  *
  * 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 pointer where to store the read object
  * @param db database to search for the object in.
  * @param short_id a prefix of the id of the object to read.
  * @param len the length of the prefix
  * @return
  * - 0 if the object was read;
  * - GIT_ENOTFOUND if the object is not in the database.
  * - GIT_EAMBIGUOUS if the prefix is ambiguous (several objects match the prefix)
  */
 GIT_EXTERN(int) git_odb_read_prefix(git_odb_object **out, git_odb *db, const git_oid *short_id, size_t len);

 /**
  * Read the header of an object from the database, without
  * reading its full contents.
  *
  * The header includes the length and the type of an object.
  *
  * 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 len_out pointer where to store the length
  * @param type_out pointer where to store the type
  * @param db database to search for the object in.
  * @param id identity of the object to read.
  * @return
  * - 0 if the object was read;
  * - GIT_ENOTFOUND if the object is not in the database.
  */
 GIT_EXTERN(int) git_odb_read_header(size_t *len_out, git_object_t *type_out, git_odb *db, const git_oid *id);

 /**
  * Determine if the given object can be found in the object database.
  *
  * @param db database to be searched for the given object.
  * @param id the object to search for.
  * @return
  * - 1, if the object was found
  * - 0, otherwise
  */
 GIT_EXTERN(int) git_odb_exists(git_odb *db, const git_oid *id);

 /**
  * Determine if an object can be found in the object database by an
  * abbreviated object ID.
  *
  * @param out The full OID of the found object if just one is found.
  * @param db The database to be searched for the given object.
  * @param short_id A prefix of the id of the object to read.
  * @param len The length of the prefix.
  * @return 0 if found, GIT_ENOTFOUND if not found, GIT_EAMBIGUOUS if multiple
  *         matches were found, other value < 0 if there was a read error.
  */
 GIT_EXTERN(int) git_odb_exists_prefix(
 	git_oid *out, git_odb *db, const git_oid *short_id, size_t len);

 /**
  * The information about object IDs to query in `git_odb_expand_ids`,
  * which will be populated upon return.
  */
 typedef struct git_odb_expand_id {
 	/** The object ID to expand */
 	git_oid id;

 	/**
 	 * The length of the object ID (in nibbles, or packets of 4 bits; the
 	 * number of hex characters)
 	 * */
 	unsigned short length;

 	/**
 	 * The (optional) type of the object to search for; leave as `0` or set
 	 * to `GIT_OBJECT_ANY` to query for any object matching the ID.
 	 */
 	git_object_t type;
 } git_odb_expand_id;

 /**
  * Determine if one or more objects can be found in the object database
  * by their abbreviated object ID and type.  The given array will be
  * updated in place:  for each abbreviated ID that is unique in the
  * database, and of the given type (if specified), the full object ID,
  * object ID length (`GIT_OID_HEXSZ`) and type will be written back to
  * the array.  For IDs that are not found (or are ambiguous), the
  * array entry will be zeroed.
  *
  * Note that since this function operates on multiple objects, the
  * underlying database will not be asked to be reloaded if an object is
  * not found (which is unlike other object database operations.)
  *
  * @param db The database to be searched for the given objects.
  * @param ids An array of short object IDs to search for
  * @param count The length of the `ids` array
  * @return 0 on success or an error code on failure
  */
 GIT_EXTERN(int) git_odb_expand_ids(
 	git_odb *db,
 	git_odb_expand_id *ids,
 	size_t count);

 /**
  * Refresh the object database to load newly added files.
  *
  * If the object databases have changed on disk while the library
  * is running, this function will force a reload of the underlying
  * indexes.
  *
  * Use this function when you're confident that an external
  * application has tampered with the ODB.
  *
  * NOTE that it is not necessary to call this function at all. The
  * library will automatically attempt to refresh the ODB
  * when a lookup fails, to see if the looked up object exists
  * on disk but hasn't been loaded yet.
  *
  * @param db database to refresh
  * @return 0 on success, error code otherwise
  */
 GIT_EXTERN(int) git_odb_refresh(struct git_odb *db);

 /**
  * List all objects available in the database
  *
  * The callback will be called for each object available in the
  * database. Note that the objects are likely to be returned in the index
  * order, which would make accessing the objects in that order inefficient.
  * Return a non-zero value from the callback to stop looping.
  *
  * @param db database to use
  * @param cb the callback to call for each object
  * @param payload data to pass to the callback
  * @return 0 on success, non-zero callback return value, or error code
  */
 GIT_EXTERN(int) git_odb_foreach(git_odb *db, git_odb_foreach_cb cb, void *payload);

 /**
  * Write an object directly into the ODB
  *
  * This method writes a full object straight into the ODB.
  * For most cases, it is preferred to write objects through a write
  * stream, which is both faster and less memory intensive, specially
  * for big objects.
  *
  * This method is provided for compatibility with custom backends
  * which are not able to support streaming writes
  *
  * @param out pointer to store the OID result of the write
  * @param odb object database where to store the object
  * @param data buffer with the data to store
  * @param len size of the buffer
  * @param type type of the data to store
  * @return 0 or an error code
  */
 GIT_EXTERN(int) git_odb_write(git_oid *out, git_odb *odb, const void *data, size_t len, git_object_t type);

 /**
  * 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 it
  * won't be effective until `git_odb_stream_finalize_write` is called
  * and returns without an error
  *
  * The stream must always be freed when done with `git_odb_stream_free` or
  * will leak memory.
  *
  * @see git_odb_stream
  *
  * @param out 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
  * @param 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 **out, git_odb *db, git_off_t size, git_object_t type);

 /**
  * Write to an odb stream
  *
  * This method will fail if the total number of received bytes exceeds the
  * size declared with `git_odb_open_wstream()`
  *
  * @param stream the stream
  * @param buffer the data to write
  * @param len the buffer's length
  * @return 0 if the write succeeded; error code otherwise
  */
 GIT_EXTERN(int) git_odb_stream_write(git_odb_stream *stream, const char *buffer, size_t len);

 /**
  * Finish writing to an odb stream
  *
  * The object will take its final name and will be available to the
  * odb.
  *
  * This method will fail if the total number of received bytes
  * differs from the size declared with `git_odb_open_wstream()`
  *
  * @param out pointer to store the resulting object's id
  * @param stream the stream
  * @return 0 on success; an error code otherwise
  */
 GIT_EXTERN(int) git_odb_stream_finalize_write(git_oid *out, git_odb_stream *stream);

 /**
  * Read from an odb stream
  *
  * Most backends don't implement streaming reads
  */
 GIT_EXTERN(int) git_odb_stream_read(git_odb_stream *stream, char *buffer, size_t len);

 /**
  * Free an odb stream
  *
  * @param stream the stream to free
  */
 GIT_EXTERN(void) git_odb_stream_free(git_odb_stream *stream);

 /**
  * 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 out pointer where to store the stream
  * @param len pointer where to store the length of the object
  * @param type pointer where to store the type of the object
  * @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 **out,
 	size_t *len,
 	git_object_t *type,
 	git_odb *db,
 	const git_oid *oid);

 /**
  * Open a stream for writing a pack file to the ODB.
  *
  * If the ODB layer understands pack files, then the given
  * packfile will likely be streamed directly to disk (and a
  * corresponding index created).  If the ODB layer does not
  * understand pack files, the objects will be stored in whatever
  * format the ODB layer uses.
  *
  * @see git_odb_writepack
  *
  * @param out pointer to the writepack functions
  * @param db object database where the stream will read from
  * @param progress_cb function to call with progress information.
  * Be aware that this is called inline with network and indexing operations,
  * so performance may be affected.
  * @param progress_payload payload for the progress callback
  */
 GIT_EXTERN(int) git_odb_write_pack(
 	git_odb_writepack **out,
 	git_odb *db,
 	git_indexer_progress_cb progress_cb,
 	void *progress_payload);

 /**
  * Determine the object-ID (sha1 hash) of a data buffer
  *
  * The resulting SHA-1 OID will be the identifier for the data
  * buffer as if the data buffer it were to written to the ODB.
  *
  * @param out the resulting object-ID.
  * @param data data to hash
  * @param len size of the data
  * @param type of the data to hash
  * @return 0 or an error code
  */
 GIT_EXTERN(int) git_odb_hash(git_oid *out, const void *data, size_t len, git_object_t type);

 /**
  * Read a file from disk and fill a git_oid with the object id
  * that the file would have if it were written to the Object
  * Database as an object of the given type (w/o applying filters).
  * Similar functionality to git.git's `git hash-object` without
  * the `-w` flag, however, with the --no-filters flag.
  * If you need filters, see git_repository_hashfile.
  *
  * @param out oid structure the result is written into.
  * @param path file to read and determine object id for
  * @param type the type of the object that will be hashed
  * @return 0 or an error code
  */
 GIT_EXTERN(int) git_odb_hashfile(git_oid *out, const char *path, git_object_t type);

 /**
  * Create a copy of an odb_object
  *
  * The returned copy must be manually freed with `git_odb_object_free`.
  * Note that because of an implementation detail, the returned copy will be
  * the same pointer as `source`: the object is internally refcounted, so the
  * copy still needs to be freed twice.
  *
  * @param dest pointer where to store the copy
  * @param source object to copy
  * @return 0 or an error code
  */
 GIT_EXTERN(int) git_odb_object_dup(git_odb_object **dest, git_odb_object *source);

 /**
  * Close an ODB object
  *
  * This method must always be called once a `git_odb_object` is no
  * longer needed, otherwise memory will leak.
  *
  * @param object object to close
  */
 GIT_EXTERN(void) git_odb_object_free(git_odb_object *object);

 /**
  * Return the OID of an ODB object
  *
  * This is the OID from which the object was read from
  *
  * @param object the object
  * @return a pointer to the OID
  */
 GIT_EXTERN(const git_oid *) git_odb_object_id(git_odb_object *object);

 /**
  * Return the data of an ODB object
  *
  * This is the uncompressed, raw data as read from the ODB,
  * without the leading header.
  *
  * This pointer is owned by the object and shall not be free'd.
  *
  * @param object the object
  * @return a pointer to the data
  */
 GIT_EXTERN(const void *) git_odb_object_data(git_odb_object *object);

 /**
  * Return the size of an ODB object
  *
  * This is the real size of the `data` buffer, not the
  * actual size of the object.
  *
  * @param object the object
  * @return the size
  */
 GIT_EXTERN(size_t) git_odb_object_size(git_odb_object *object);

 /**
  * Return the type of an ODB object
  *
  * @param object the object
  * @return the type
  */
 GIT_EXTERN(git_object_t) 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 <sys/odb_backend.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 <sys/odb_backend.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
	/*
	* 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_h__
	#define INCLUDE_git_odb_h__

	#include "common.h"
	#include "types.h"
	#include "oid.h"
	#include "oidarray.h"
	#include "indexer.h"

	/**
	* @file git2/odb.h
	* @brief Git object database routines
	* @defgroup git_odb Git object database routines
	* @ingroup Git
	* @{
	*/
	GIT_BEGIN_DECL

	/**
	* Function type for callbacks from git_odb_foreach.
	*/
	typedef int GIT_CALLBACK(git_odb_foreach_cb)(const git_oid id, void payload);

	/**
	* Create a new object database with no backends.
	*
	* Before the ODB can be used for read/writing, a custom database
	* backend must be manually added using `git_odb_add_backend()`
	*
	* @param out location to store the database pointer, if opened.
	* Set to NULL if the open failed.
	* @return 0 or an error code
	*/
	GIT_EXTERN(int) git_odb_new(git_odb **out);

	/**
	* Create a new object database and automatically add
	* the two default backends:
	*
	* - git_odb_backend_loose: read and write loose object files
	* from disk, assuming `objects_dir` as the Objects folder
	*
	* - git_odb_backend_pack: read objects from packfiles,
	* assuming `objects_dir` as the Objects folder which
	* contains a 'pack/' folder with the corresponding data
	*
	* @param out location to store the database pointer, if opened.
	* Set to NULL if the open failed.
	* @param objects_dir path of the backends' "objects" directory.
	* @return 0 or an error code
	*/
	GIT_EXTERN(int) git_odb_open(git_odb *out, const char objects_dir);

	/**
	* Add an on-disk alternate to an existing Object DB.
	*
	* Note that the added path must point to an `objects`, not
	* to a full repository, to use it as an alternate store.
	*
	* Alternate backends are always checked for objects after
	* all the main backends have been exhausted.
	*
	* Writing is disabled on alternate backends.
	*
	* @param odb database to add the backend to
	* @param path path to the objects folder for the alternate
	* @return 0 on success; error code otherwise
	*/
	GIT_EXTERN(int) git_odb_add_disk_alternate(git_odb odb, const char path);

	/**
	* Close an open object database.
	*
	* @param db database pointer to close. If NULL no action is taken.
	*/
	GIT_EXTERN(void) git_odb_free(git_odb *db);

	/**
	* Read an object from the database.
	*
	* This method queries all available 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 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
	* - 0 if the object was read;
	* - GIT_ENOTFOUND if the object is not in the database.
	*/
	GIT_EXTERN(int) git_odb_read(git_odb_object *out, git_odb db, const git_oid *id);

	/**
	* Read an object from the database, given a prefix
	* of its identifier.
	*
	* This method queries all available ODB backends
	* trying to match the 'len' first hexadecimal
	* characters of the 'short_id'.
	* The remaining (GIT_OID_HEXSZ-len)*4 bits of
	* 'short_id' must be 0s.
	* 'len' must be at least GIT_OID_MINPREFIXLEN,
	* and the prefix must be long enough to identify
	* a unique object in all the backends; the
	* method will fail otherwise.
	*
	* 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 pointer where to store the read object
	* @param db database to search for the object in.
	* @param short_id a prefix of the id of the object to read.
	* @param len the length of the prefix
	* @return
	* - 0 if the object was read;
	* - GIT_ENOTFOUND if the object is not in the database.
	* - GIT_EAMBIGUOUS if the prefix is ambiguous (several objects match the prefix)
	*/
	GIT_EXTERN(int) git_odb_read_prefix(git_odb_object *out, git_odb db, const git_oid *short_id, size_t len);

	/**
	* Read the header of an object from the database, without
	* reading its full contents.
	*
	* The header includes the length and the type of an object.
	*
	* 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 len_out pointer where to store the length
	* @param type_out pointer where to store the type
	* @param db database to search for the object in.
	* @param id identity of the object to read.
	* @return
	* - 0 if the object was read;
	* - GIT_ENOTFOUND if the object is not in the database.
	*/
	GIT_EXTERN(int) git_odb_read_header(size_t len_out, git_object_t type_out, git_odb db, const git_oid id);

	/**
	* Determine if the given object can be found in the object database.
	*
	* @param db database to be searched for the given object.
	* @param id the object to search for.
	* @return
	* - 1, if the object was found
	* - 0, otherwise
	*/
	GIT_EXTERN(int) git_odb_exists(git_odb db, const git_oid id);

	/**
	* Determine if an object can be found in the object database by an
	* abbreviated object ID.
	*
	* @param out The full OID of the found object if just one is found.
	* @param db The database to be searched for the given object.
	* @param short_id A prefix of the id of the object to read.
	* @param len The length of the prefix.
	* @return 0 if found, GIT_ENOTFOUND if not found, GIT_EAMBIGUOUS if multiple
	* matches were found, other value < 0 if there was a read error.
	*/
	GIT_EXTERN(int) git_odb_exists_prefix(
	git_oid out, git_odb db, const git_oid *short_id, size_t len);

	/**
	* The information about object IDs to query in `git_odb_expand_ids`,
	* which will be populated upon return.
	*/
	typedef struct git_odb_expand_id {
	/** The object ID to expand */
	git_oid id;

	/**
	* The length of the object ID (in nibbles, or packets of 4 bits; the
	* number of hex characters)
	* */
	unsigned short length;

	/**
	* The (optional) type of the object to search for; leave as `0` or set
	* to `GIT_OBJECT_ANY` to query for any object matching the ID.
	*/
	git_object_t type;
	} git_odb_expand_id;

	/**
	* Determine if one or more objects can be found in the object database
	* by their abbreviated object ID and type. The given array will be
	* updated in place: for each abbreviated ID that is unique in the
	* database, and of the given type (if specified), the full object ID,
	* object ID length (`GIT_OID_HEXSZ`) and type will be written back to
	* the array. For IDs that are not found (or are ambiguous), the
	* array entry will be zeroed.
	*
	* Note that since this function operates on multiple objects, the
	* underlying database will not be asked to be reloaded if an object is
	* not found (which is unlike other object database operations.)
	*
	* @param db The database to be searched for the given objects.
	* @param ids An array of short object IDs to search for
	* @param count The length of the `ids` array
	* @return 0 on success or an error code on failure
	*/
	GIT_EXTERN(int) git_odb_expand_ids(
	git_odb *db,
	git_odb_expand_id *ids,
	size_t count);

	/**
	* Refresh the object database to load newly added files.
	*
	* If the object databases have changed on disk while the library
	* is running, this function will force a reload of the underlying
	* indexes.
	*
	* Use this function when you're confident that an external
	* application has tampered with the ODB.
	*
	* NOTE that it is not necessary to call this function at all. The
	* library will automatically attempt to refresh the ODB
	* when a lookup fails, to see if the looked up object exists
	* on disk but hasn't been loaded yet.
	*
	* @param db database to refresh
	* @return 0 on success, error code otherwise
	*/
	GIT_EXTERN(int) git_odb_refresh(struct git_odb *db);

	/**
	* List all objects available in the database
	*
	* The callback will be called for each object available in the
	* database. Note that the objects are likely to be returned in the index
	* order, which would make accessing the objects in that order inefficient.
	* Return a non-zero value from the callback to stop looping.
	*
	* @param db database to use
	* @param cb the callback to call for each object
	* @param payload data to pass to the callback
	* @return 0 on success, non-zero callback return value, or error code
	*/
	GIT_EXTERN(int) git_odb_foreach(git_odb db, git_odb_foreach_cb cb, void payload);

	/**
	* Write an object directly into the ODB
	*
	* This method writes a full object straight into the ODB.
	* For most cases, it is preferred to write objects through a write
	* stream, which is both faster and less memory intensive, specially
	* for big objects.
	*
	* This method is provided for compatibility with custom backends
	* which are not able to support streaming writes
	*
	* @param out pointer to store the OID result of the write
	* @param odb object database where to store the object
	* @param data buffer with the data to store
	* @param len size of the buffer
	* @param type type of the data to store
	* @return 0 or an error code
	*/
	GIT_EXTERN(int) git_odb_write(git_oid out, git_odb odb, const void *data, size_t len, git_object_t type);

	/**
	* 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 it
	* won't be effective until `git_odb_stream_finalize_write` is called
	* and returns without an error
	*
	* The stream must always be freed when done with `git_odb_stream_free` or
	* will leak memory.
	*
	* @see git_odb_stream
	*
	* @param out 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
	* @param 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 *out, git_odb db, git_off_t size, git_object_t type);

	/**
	* Write to an odb stream
	*
	* This method will fail if the total number of received bytes exceeds the
	* size declared with `git_odb_open_wstream()`
	*
	* @param stream the stream
	* @param buffer the data to write
	* @param len the buffer's length
	* @return 0 if the write succeeded; error code otherwise
	*/
	GIT_EXTERN(int) git_odb_stream_write(git_odb_stream stream, const char buffer, size_t len);

	/**
	* Finish writing to an odb stream
	*
	* The object will take its final name and will be available to the
	* odb.
	*
	* This method will fail if the total number of received bytes
	* differs from the size declared with `git_odb_open_wstream()`
	*
	* @param out pointer to store the resulting object's id
	* @param stream the stream
	* @return 0 on success; an error code otherwise
	*/
	GIT_EXTERN(int) git_odb_stream_finalize_write(git_oid out, git_odb_stream stream);

	/**
	* Read from an odb stream
	*
	* Most backends don't implement streaming reads
	*/
	GIT_EXTERN(int) git_odb_stream_read(git_odb_stream stream, char buffer, size_t len);

	/**
	* Free an odb stream
	*
	* @param stream the stream to free
	*/
	GIT_EXTERN(void) git_odb_stream_free(git_odb_stream *stream);

	/**
	* 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 out pointer where to store the stream
	* @param len pointer where to store the length of the object
	* @param type pointer where to store the type of the object
	* @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 **out,
	size_t *len,
	git_object_t *type,
	git_odb *db,
	const git_oid *oid);

	/**
	* Open a stream for writing a pack file to the ODB.
	*
	* If the ODB layer understands pack files, then the given
	* packfile will likely be streamed directly to disk (and a
	* corresponding index created). If the ODB layer does not
	* understand pack files, the objects will be stored in whatever
	* format the ODB layer uses.
	*
	* @see git_odb_writepack
	*
	* @param out pointer to the writepack functions
	* @param db object database where the stream will read from
	* @param progress_cb function to call with progress information.
	* Be aware that this is called inline with network and indexing operations,
	* so performance may be affected.
	* @param progress_payload payload for the progress callback
	*/
	GIT_EXTERN(int) git_odb_write_pack(
	git_odb_writepack **out,
	git_odb *db,
	git_indexer_progress_cb progress_cb,
	void *progress_payload);

	/**
	* Determine the object-ID (sha1 hash) of a data buffer
	*
	* The resulting SHA-1 OID will be the identifier for the data
	* buffer as if the data buffer it were to written to the ODB.
	*
	* @param out the resulting object-ID.
	* @param data data to hash
	* @param len size of the data
	* @param type of the data to hash
	* @return 0 or an error code
	*/
	GIT_EXTERN(int) git_odb_hash(git_oid out, const void data, size_t len, git_object_t type);

	/**
	* Read a file from disk and fill a git_oid with the object id
	* that the file would have if it were written to the Object
	* Database as an object of the given type (w/o applying filters).
	* Similar functionality to git.git's `git hash-object` without
	* the `-w` flag, however, with the --no-filters flag.
	* If you need filters, see git_repository_hashfile.
	*
	* @param out oid structure the result is written into.
	* @param path file to read and determine object id for
	* @param type the type of the object that will be hashed
	* @return 0 or an error code
	*/
	GIT_EXTERN(int) git_odb_hashfile(git_oid out, const char path, git_object_t type);

	/**
	* Create a copy of an odb_object
	*
	* The returned copy must be manually freed with `git_odb_object_free`.
	* Note that because of an implementation detail, the returned copy will be
	* the same pointer as `source`: the object is internally refcounted, so the
	* copy still needs to be freed twice.
	*
	* @param dest pointer where to store the copy
	* @param source object to copy
	* @return 0 or an error code
	*/
	GIT_EXTERN(int) git_odb_object_dup(git_odb_object *dest, git_odb_object source);

	/**
	* Close an ODB object
	*
	* This method must always be called once a `git_odb_object` is no
	* longer needed, otherwise memory will leak.
	*
	* @param object object to close
	*/
	GIT_EXTERN(void) git_odb_object_free(git_odb_object *object);

	/**
	* Return the OID of an ODB object
	*
	* This is the OID from which the object was read from
	*
	* @param object the object
	* @return a pointer to the OID
	*/
	GIT_EXTERN(const git_oid ) git_odb_object_id(git_odb_object object);

	/**
	* Return the data of an ODB object
	*
	* This is the uncompressed, raw data as read from the ODB,
	* without the leading header.
	*
	* This pointer is owned by the object and shall not be free'd.
	*
	* @param object the object
	* @return a pointer to the data
	*/
	GIT_EXTERN(const void ) git_odb_object_data(git_odb_object object);

	/**
	* Return the size of an ODB object
	*
	* This is the real size of the `data` buffer, not the
	* actual size of the object.
	*
	* @param object the object
	* @return the size
	*/
	GIT_EXTERN(size_t) git_odb_object_size(git_odb_object *object);

	/**
	* Return the type of an ODB object
	*
	* @param object the object
	* @return the type
	*/
	GIT_EXTERN(git_object_t) 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 <sys/odb_backend.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 <sys/odb_backend.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