git/commit-graph.h
Junio C Hamano 7727da99df Merge branch 'ds/ahead-behind'
"git for-each-ref" learns '%(ahead-behind:<base>)' that computes the
distances from a single reference point in the history with bunch
of commits in bulk.

* ds/ahead-behind:
  commit-reach: add tips_reachable_from_bases()
  for-each-ref: add ahead-behind format atom
  commit-reach: implement ahead_behind() logic
  commit-graph: introduce `ensure_generations_valid()`
  commit-graph: return generation from memory
  commit-graph: simplify compute_generation_numbers()
  commit-graph: refactor compute_topological_levels()
  for-each-ref: explicitly test no matches
  for-each-ref: add --stdin option
2023-04-06 13:38:21 -07:00

201 lines
6.4 KiB
C

#ifndef COMMIT_GRAPH_H
#define COMMIT_GRAPH_H
#include "object-store.h"
#include "oidset.h"
#define GIT_TEST_COMMIT_GRAPH "GIT_TEST_COMMIT_GRAPH"
#define GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE "GIT_TEST_COMMIT_GRAPH_DIE_ON_PARSE"
#define GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS "GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS"
/*
* This method is only used to enhance coverage of the commit-graph
* feature in the test suite with the GIT_TEST_COMMIT_GRAPH and
* GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS environment variables. Do not
* call this method oustide of a builtin, and only if you know what
* you are doing!
*/
void git_test_write_commit_graph_or_die(void);
struct commit;
struct bloom_filter_settings;
struct repository;
struct raw_object_store;
struct string_list;
char *get_commit_graph_filename(struct object_directory *odb);
char *get_commit_graph_chain_filename(struct object_directory *odb);
int open_commit_graph(const char *graph_file, int *fd, struct stat *st);
/*
* Given a commit struct, try to fill the commit struct info, including:
* 1. tree object
* 2. date
* 3. parents.
*
* Returns 1 if and only if the commit was found in the packed graph.
*
* See parse_commit_buffer() for the fallback after this call.
*/
int parse_commit_in_graph(struct repository *r, struct commit *item);
/*
* Fills `*pos` with the graph position of `c`, and returns 1 if `c` is
* found in the commit-graph belonging to `r`, or 0 otherwise.
* Initializes the commit-graph belonging to `r` if it hasn't been
* already.
*
* Note: this is a low-level helper that does not alter any slab data
* associated with `c`. Useful in circumstances where the slab data is
* already being modified (e.g., writing the commit-graph itself).
*
* In most cases, callers should use `parse_commit_in_graph()` instead.
*/
int repo_find_commit_pos_in_graph(struct repository *r, struct commit *c,
uint32_t *pos);
/*
* Look up the given commit ID in the commit-graph. This will only return a
* commit if the ID exists both in the graph and in the object database such
* that we don't return commits whose object has been pruned. Otherwise, this
* function returns `NULL`.
*/
struct commit *lookup_commit_in_graph(struct repository *repo, const struct object_id *id);
/*
* It is possible that we loaded commit contents from the commit buffer,
* but we also want to ensure the commit-graph content is correctly
* checked and filled. Fill the graph_pos and generation members of
* the given commit.
*/
void load_commit_graph_info(struct repository *r, struct commit *item);
struct tree *get_commit_tree_in_graph(struct repository *r,
const struct commit *c);
struct commit_graph {
const unsigned char *data;
size_t data_len;
unsigned char hash_len;
unsigned char num_chunks;
uint32_t num_commits;
struct object_id oid;
char *filename;
struct object_directory *odb;
uint32_t num_commits_in_base;
unsigned int read_generation_data;
struct commit_graph *base_graph;
const uint32_t *chunk_oid_fanout;
const unsigned char *chunk_oid_lookup;
const unsigned char *chunk_commit_data;
const unsigned char *chunk_generation_data;
const unsigned char *chunk_generation_data_overflow;
const unsigned char *chunk_extra_edges;
const unsigned char *chunk_base_graphs;
const unsigned char *chunk_bloom_indexes;
const unsigned char *chunk_bloom_data;
struct topo_level_slab *topo_levels;
struct bloom_filter_settings *bloom_filter_settings;
};
struct commit_graph *load_commit_graph_one_fd_st(struct repository *r,
int fd, struct stat *st,
struct object_directory *odb);
struct commit_graph *read_commit_graph_one(struct repository *r,
struct object_directory *odb);
/*
* Callers should initialize the repo_settings with prepare_repo_settings()
* prior to calling parse_commit_graph().
*/
struct commit_graph *parse_commit_graph(struct repo_settings *s,
void *graph_map, size_t graph_size);
/*
* Return 1 if and only if the repository has a commit-graph
* file and generation numbers are computed in that file.
*/
int generation_numbers_enabled(struct repository *r);
/*
* Return 1 if and only if the repository has a commit-graph
* file and generation data chunk has been written for the file.
*/
int corrected_commit_dates_enabled(struct repository *r);
struct bloom_filter_settings *get_bloom_filter_settings(struct repository *r);
enum commit_graph_write_flags {
COMMIT_GRAPH_WRITE_APPEND = (1 << 0),
COMMIT_GRAPH_WRITE_PROGRESS = (1 << 1),
COMMIT_GRAPH_WRITE_SPLIT = (1 << 2),
COMMIT_GRAPH_WRITE_BLOOM_FILTERS = (1 << 3),
COMMIT_GRAPH_NO_WRITE_BLOOM_FILTERS = (1 << 4),
};
enum commit_graph_split_flags {
COMMIT_GRAPH_SPLIT_UNSPECIFIED = 0,
COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED = 1,
COMMIT_GRAPH_SPLIT_REPLACE = 2
};
struct commit_graph_opts {
int size_multiple;
int max_commits;
timestamp_t expire_time;
enum commit_graph_split_flags split_flags;
int max_new_filters;
};
/*
* The write_commit_graph* methods return zero on success
* and a negative value on failure. Note that if the repository
* is not compatible with the commit-graph feature, then the
* methods will return 0 without writing a commit-graph.
*/
int write_commit_graph_reachable(struct object_directory *odb,
enum commit_graph_write_flags flags,
const struct commit_graph_opts *opts);
int write_commit_graph(struct object_directory *odb,
const struct string_list *pack_indexes,
struct oidset *commits,
enum commit_graph_write_flags flags,
const struct commit_graph_opts *opts);
#define COMMIT_GRAPH_VERIFY_SHALLOW (1 << 0)
int verify_commit_graph(struct repository *r, struct commit_graph *g, int flags);
void close_commit_graph(struct raw_object_store *);
void free_commit_graph(struct commit_graph *);
/*
* Disable further use of the commit graph in this process when parsing a
* "struct commit".
*/
void disable_commit_graph(struct repository *r);
struct commit_graph_data {
uint32_t graph_pos;
timestamp_t generation;
};
/*
* Commits should be parsed before accessing generation, graph positions.
*/
timestamp_t commit_graph_generation(const struct commit *);
uint32_t commit_graph_position(const struct commit *);
/*
* After this method, all commits reachable from those in the given
* list will have non-zero, non-infinite generation numbers.
*/
void ensure_generations_valid(struct repository *r,
struct commit **commits, size_t nr);
#endif