* 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__
* @brief Git object database routines
* @defgroup git_odb Git object database routines
* 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.
* - 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
* 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
* '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
* - 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.
* - 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.
* - 1, if the object was found
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
* @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 */
* The length of the object ID (in nibbles, or packets of 4 bits; the
* number of hex characters)
* 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.
* 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(
* 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
* 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
* 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
* @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_object_size_t size, git_object_t type);
* 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
* 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);
* @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.
* @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(
* 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.
* @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_indexer_progress_cb progress_cb,
* 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);
* 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
GIT_EXTERN(size_t) git_odb_object_size(git_odb_object *object);
* Return the type of an ODB object
* @param object the object
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.
It is recommended that you Edit text format, this type of Fix handles quite a lot in one request
