git/pack-bitmap.h
Taylor Blau 83296d20e8 pack-bitmap: return multiple packs via reuse_partial_packfile_from_bitmap()
Further prepare for enabling verbatim pack-reuse over multiple packfiles
by changing the signature of reuse_partial_packfile_from_bitmap() to
populate an array of `struct bitmapped_pack *`'s instead of a pointer to
a single packfile.

Since the array we're filling out is sized dynamically[^1], add an
additional `size_t *` parameter which will hold the number of reusable
packs (equal to the number of elements in the array).

Note that since we still have not implemented true multi-pack reuse,
these changes aren't propagated out to the rest of the caller in
builtin/pack-objects.c.

In the interim state, we expect that the array has a single element, and
we use that element to fill out the static `reuse_packfile` variable
(which is a bog-standard `struct packed_git *`). Future commits will
continue to push this change further out through the pack-objects code.

[^1]: That is, even though we know the number of packs which are
  candidates for pack-reuse, we do not know how many of those
  candidates we can actually reuse.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-12-14 14:38:08 -08:00

129 lines
4 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;
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)
/*
* The width in bytes of a single triplet in the lookup table
* extension:
* (commit_pos, offset, xor_row)
*
* whose fields ar 32-, 64-, 32- bits wide, respectively.
*/
#define BITMAP_LOOKUP_TABLE_TRIPLET_WIDTH (16)
enum pack_bitmap_opts {
BITMAP_OPT_FULL_DAG = 0x1,
BITMAP_OPT_HASH_CACHE = 0x4,
BITMAP_OPT_LOOKUP_TABLE = 0x10,
};
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 bitmapped_pack {
struct packed_git *p;
uint32_t bitmap_pos;
uint32_t bitmap_nr;
uint32_t pack_int_id; /* MIDX only */
};
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);
int test_bitmap_hashes(struct repository *r);
#define GIT_TEST_PACK_USE_BITMAP_BOUNDARY_TRAVERSAL \
"GIT_TEST_PACK_USE_BITMAP_BOUNDARY_TRAVERSAL"
struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs,
int filter_provided_objects);
uint32_t midx_preferred_pack(struct bitmap_index *bitmap_git);
void reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
struct bitmapped_pack **packs_out,
size_t *packs_nr_out,
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(const 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);
int verify_bitmap_files(struct repository *r);
#endif