git/midx.h

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#ifndef MIDX_H
#define MIDX_H
#include "repository.h"
struct object_id;
struct pack_entry;
struct repository;
#define GIT_TEST_MULTI_PACK_INDEX "GIT_TEST_MULTI_PACK_INDEX"
#define GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP \
"GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP"
struct multi_pack_index {
struct multi_pack_index *next;
const unsigned char *data;
size_t data_len;
pack-revindex: read multi-pack reverse indexes Implement reading for multi-pack reverse indexes, as described in the previous patch. Note that these functions don't yet have any callers, and won't until multi-pack reachability bitmaps are introduced in a later patch series. In the meantime, this patch implements some of the infrastructure necessary to support multi-pack bitmaps. There are three new functions exposed by the revindex API: - load_midx_revindex(): loads the reverse index corresponding to the given multi-pack index. - midx_to_pack_pos() and pack_pos_to_midx(): these convert between the multi-pack index and pseudo-pack order. load_midx_revindex() and pack_pos_to_midx() are both relatively straightforward. load_midx_revindex() needs a few functions to be exposed from the midx API. One to get the checksum of a midx, and another to get the .rev's filename. Similar to recent changes in the packed_git struct, three new fields are added to the multi_pack_index struct: one to keep track of the size, one to keep track of the mmap'd pointer, and another to point past the header and at the reverse index's data. pack_pos_to_midx() simply reads the corresponding entry out of the table. midx_to_pack_pos() is the trickiest, since it needs to find an object's position in the psuedo-pack order, but that order can only be recovered in the .rev file itself. This mapping can be implemented with a binary search, but note that the thing we're binary searching over isn't an array of values, but rather a permuted order of those values. So, when comparing two items, it's helpful to keep in mind the difference. Instead of a traditional binary search, where you are comparing two things directly, here we're comparing a (pack, offset) tuple with an index into the multi-pack index. That index describes another (pack, offset) tuple, and it is _those_ two tuples that are compared. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30 23:04:26 +08:00
const uint32_t *revindex_data;
const uint32_t *revindex_map;
size_t revindex_len;
uint32_t signature;
unsigned char version;
unsigned char hash_len;
unsigned char num_chunks;
uint32_t num_packs;
uint32_t num_objects;
int local;
const unsigned char *chunk_pack_names;
const uint32_t *chunk_oid_fanout;
const unsigned char *chunk_oid_lookup;
const unsigned char *chunk_object_offsets;
const unsigned char *chunk_large_offsets;
const char **pack_names;
struct packed_git **packs;
char object_dir[FLEX_ARRAY];
};
#define MIDX_PROGRESS (1 << 0)
#define MIDX_WRITE_REV_INDEX (1 << 1)
#define MIDX_WRITE_BITMAP (1 << 2)
const unsigned char *get_midx_checksum(struct multi_pack_index *m);
char *get_midx_filename(const char *object_dir);
pack-revindex: read multi-pack reverse indexes Implement reading for multi-pack reverse indexes, as described in the previous patch. Note that these functions don't yet have any callers, and won't until multi-pack reachability bitmaps are introduced in a later patch series. In the meantime, this patch implements some of the infrastructure necessary to support multi-pack bitmaps. There are three new functions exposed by the revindex API: - load_midx_revindex(): loads the reverse index corresponding to the given multi-pack index. - midx_to_pack_pos() and pack_pos_to_midx(): these convert between the multi-pack index and pseudo-pack order. load_midx_revindex() and pack_pos_to_midx() are both relatively straightforward. load_midx_revindex() needs a few functions to be exposed from the midx API. One to get the checksum of a midx, and another to get the .rev's filename. Similar to recent changes in the packed_git struct, three new fields are added to the multi_pack_index struct: one to keep track of the size, one to keep track of the mmap'd pointer, and another to point past the header and at the reverse index's data. pack_pos_to_midx() simply reads the corresponding entry out of the table. midx_to_pack_pos() is the trickiest, since it needs to find an object's position in the psuedo-pack order, but that order can only be recovered in the .rev file itself. This mapping can be implemented with a binary search, but note that the thing we're binary searching over isn't an array of values, but rather a permuted order of those values. So, when comparing two items, it's helpful to keep in mind the difference. Instead of a traditional binary search, where you are comparing two things directly, here we're comparing a (pack, offset) tuple with an index into the multi-pack index. That index describes another (pack, offset) tuple, and it is _those_ two tuples that are compared. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30 23:04:26 +08:00
char *get_midx_rev_filename(struct multi_pack_index *m);
struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local);
int prepare_midx_pack(struct repository *r, struct multi_pack_index *m, uint32_t pack_int_id);
int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result);
off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos);
uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos);
struct object_id *nth_midxed_object_oid(struct object_id *oid,
struct multi_pack_index *m,
uint32_t n);
int fill_midx_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m);
int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name);
int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local);
int write_midx_file(const char *object_dir, const char *preferred_pack_name, unsigned flags);
void clear_midx_file(struct repository *r);
int verify_midx_file(struct repository *r, const char *object_dir, unsigned flags);
int expire_midx_packs(struct repository *r, const char *object_dir, unsigned flags);
int midx_repack(struct repository *r, const char *object_dir, size_t batch_size, unsigned flags);
void close_midx(struct multi_pack_index *m);
#endif