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/*
* 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_commit_graph_h__
#define INCLUDE_commit_graph_h__
#include "common.h"
#include "git2/types.h"
#include "git2/sys/commit_graph.h"
#include "map.h"
#include "vector.h"
#include "oid.h"
#include "hash.h"
/**
* A commit-graph file.
*
* This file contains metadata about commits, particularly the generation
* number for each one. This can help speed up graph operations without
* requiring a full graph traversal.
*
* Support for this feature was added in git 2.19.
*/
typedef struct git_commit_graph_file {
git_map graph_map;
/* The type of object IDs in the commit graph file. */
git_oid_t oid_type;
/* The OID Fanout table. */
const uint32_t *oid_fanout;
/* The total number of commits in the graph. */
uint32_t num_commits;
/* The OID Lookup table. */
unsigned char *oid_lookup;
/*
* The Commit Data table. Each entry contains the OID of the commit followed
* by two 8-byte fields in network byte order:
* - The indices of the first two parents (32 bits each).
* - The generation number (first 30 bits) and commit time in seconds since
* UNIX epoch (34 bits).
*/
const unsigned char *commit_data;
/*
* The Extra Edge List table. Each 4-byte entry is a network byte order index
* of one of the i-th (i > 0) parents of commits in the `commit_data` table,
* when the commit has more than 2 parents.
*/
const unsigned char *extra_edge_list;
/* The number of entries in the Extra Edge List table. Each entry is 4 bytes wide. */
size_t num_extra_edge_list;
/* The trailer of the file. Contains the SHA1-checksum of the whole file. */
unsigned char checksum[GIT_HASH_SHA1_SIZE];
} git_commit_graph_file;
/**
* An entry in the commit-graph file. Provides a subset of the information that
* can be obtained from the commit header.
*/
typedef struct git_commit_graph_entry {
/* The generation number of the commit within the graph */
size_t generation;
/* Time in seconds from UNIX epoch. */
git_time_t commit_time;
/* The number of parents of the commit. */
size_t parent_count;
/*
* The indices of the parent commits within the Commit Data table. The value
* of `GIT_COMMIT_GRAPH_MISSING_PARENT` indicates that no parent is in that
* position.
*/
size_t parent_indices[2];
/* The index within the Extra Edge List of any parent after the first two. */
size_t extra_parents_index;
/* The object ID of the root tree of the commit. */
git_oid tree_oid;
/* The object ID hash of the requested commit. */
git_oid sha1;
} git_commit_graph_entry;
/* A wrapper for git_commit_graph_file to enable lazy loading in the ODB. */
struct git_commit_graph {
/* The path to the commit-graph file. Something like ".git/objects/info/commit-graph". */
git_str filename;
/* The underlying commit-graph file. */
git_commit_graph_file *file;
/* The object ID types in the commit graph. */
git_oid_t oid_type;
/* Whether the commit-graph file was already checked for validity. */
bool checked;
};
/** Create a new commit-graph, optionally opening the underlying file. */
int git_commit_graph_new(
git_commit_graph **cgraph_out,
const char *objects_dir,
bool open_file,
git_oid_t oid_type);
/** Validate the checksum of a commit graph */
int git_commit_graph_validate(git_commit_graph *cgraph);
/** Open and validate a commit-graph file. */
int git_commit_graph_file_open(
git_commit_graph_file **file_out,
const char *path,
git_oid_t oid_type);
/*
* Attempt to get the git_commit_graph's commit-graph file. This object is
* still owned by the git_commit_graph. If the repository does not contain a commit graph,
* it will return GIT_ENOTFOUND.
*
* This function is not thread-safe.
*/
int git_commit_graph_get_file(git_commit_graph_file **file_out, git_commit_graph *cgraph);
/* Marks the commit-graph file as needing a refresh. */
void git_commit_graph_refresh(git_commit_graph *cgraph);
/*
* A writer for `commit-graph` files.
*/
struct git_commit_graph_writer {
/*
* The path of the `objects/info` directory where the `commit-graph` will be
* stored.
*/
git_str objects_info_dir;
/* The object ID type of the commit graph. */
git_oid_t oid_type;
/* The list of packed commits. */
git_vector commits;
};
int git_commit_graph__writer_dump(
git_str *cgraph,
git_commit_graph_writer *w,
git_commit_graph_writer_options *opts);
/*
* Returns whether the git_commit_graph_file needs to be reloaded since the
* contents of the commit-graph file have changed on disk.
*/
bool git_commit_graph_file_needs_refresh(
const git_commit_graph_file *file, const char *path);
int git_commit_graph_entry_find(
git_commit_graph_entry *e,
const git_commit_graph_file *file,
const git_oid *short_oid,
size_t len);
int git_commit_graph_entry_parent(
git_commit_graph_entry *parent,
const git_commit_graph_file *file,
const git_commit_graph_entry *entry,
size_t n);
int git_commit_graph_file_close(git_commit_graph_file *cgraph);
void git_commit_graph_file_free(git_commit_graph_file *cgraph);
/* This is exposed for use in the fuzzers. */
int git_commit_graph_file_parse(
git_commit_graph_file *file,
const unsigned char *data,
size_t size);
#endif
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