git/pack-bitmap.h
Taylor Blau 6d08b9d4ca builtin/repack.c: make largest pack preferred
When repacking into a geometric series and writing a multi-pack bitmap,
it is beneficial to have the largest resulting pack be the preferred
object source in the bitmap's MIDX, since selecting the large packs can
lead to fewer broken delta chains and better compression.

Teach 'git repack' to identify this pack and pass it to the MIDX write
machinery in order to mark it as preferred.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-28 21:20:56 -07:00

106 lines
3.5 KiB
C

#ifndef PACK_BITMAP_H
#define PACK_BITMAP_H
#include "ewah/ewok.h"
#include "khash.h"
#include "pack.h"
#include "pack-objects.h"
#include "string-list.h"
struct commit;
struct repository;
struct rev_info;
struct list_objects_filter_options;
static const char BITMAP_IDX_SIGNATURE[] = {'B', 'I', 'T', 'M'};
struct bitmap_disk_header {
char magic[ARRAY_SIZE(BITMAP_IDX_SIGNATURE)];
uint16_t version;
uint16_t options;
uint32_t entry_count;
unsigned char checksum[GIT_MAX_RAWSZ];
};
#define NEEDS_BITMAP (1u<<22)
enum pack_bitmap_opts {
BITMAP_OPT_FULL_DAG = 1,
BITMAP_OPT_HASH_CACHE = 4,
};
enum pack_bitmap_flags {
BITMAP_FLAG_REUSE = 0x1
};
typedef int (*show_reachable_fn)(
const struct object_id *oid,
enum object_type type,
int flags,
uint32_t hash,
struct packed_git *found_pack,
off_t found_offset);
struct bitmap_index;
struct bitmap_index *prepare_bitmap_git(struct repository *r);
struct bitmap_index *prepare_midx_bitmap_git(struct multi_pack_index *midx);
void count_bitmap_commit_list(struct bitmap_index *, uint32_t *commits,
uint32_t *trees, uint32_t *blobs, uint32_t *tags);
void traverse_bitmap_commit_list(struct bitmap_index *,
struct rev_info *revs,
show_reachable_fn show_reachable);
void test_bitmap_walk(struct rev_info *revs);
int test_bitmap_commits(struct repository *r);
struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs,
struct list_objects_filter_options *filter,
int filter_provided_objects);
uint32_t midx_preferred_pack(struct bitmap_index *bitmap_git);
int reuse_partial_packfile_from_bitmap(struct bitmap_index *,
struct packed_git **packfile,
uint32_t *entries,
struct bitmap **reuse_out);
int rebuild_existing_bitmaps(struct bitmap_index *, struct packing_data *mapping,
kh_oid_map_t *reused_bitmaps, int show_progress);
void free_bitmap_index(struct bitmap_index *);
int bitmap_walk_contains(struct bitmap_index *,
struct bitmap *bitmap, const struct object_id *oid);
/*
* After a traversal has been performed by prepare_bitmap_walk(), this can be
* queried to see if a particular object was reachable from any of the
* objects flagged as UNINTERESTING.
*/
int bitmap_has_oid_in_uninteresting(struct bitmap_index *, const struct object_id *oid);
off_t get_disk_usage_from_bitmap(struct bitmap_index *, struct rev_info *);
void bitmap_writer_show_progress(int show);
void bitmap_writer_set_checksum(unsigned char *sha1);
void bitmap_writer_build_type_index(struct packing_data *to_pack,
struct pack_idx_entry **index,
uint32_t index_nr);
uint32_t *create_bitmap_mapping(struct bitmap_index *bitmap_git,
struct packing_data *mapping);
int rebuild_bitmap(const uint32_t *reposition,
struct ewah_bitmap *source,
struct bitmap *dest);
struct ewah_bitmap *bitmap_for_commit(struct bitmap_index *bitmap_git,
struct commit *commit);
void bitmap_writer_select_commits(struct commit **indexed_commits,
unsigned int indexed_commits_nr, int max_bitmaps);
int bitmap_writer_build(struct packing_data *to_pack);
void bitmap_writer_finish(struct pack_idx_entry **index,
uint32_t index_nr,
const char *filename,
uint16_t options);
char *midx_bitmap_filename(struct multi_pack_index *midx);
char *pack_bitmap_filename(struct packed_git *p);
int bitmap_is_midx(struct bitmap_index *bitmap_git);
const struct string_list *bitmap_preferred_tips(struct repository *r);
int bitmap_is_preferred_refname(struct repository *r, const char *refname);
#endif