mirror of
https://github.com/git/git.git
synced 2024-11-24 02:17:02 +08:00
afb32e8101
Time complexities for pack_pos_to_midx and midx_to_pack_pos are swapped, correct it. Signed-off-by: Kyle Zhao <kylezhao@tencent.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
128 lines
4.3 KiB
C
128 lines
4.3 KiB
C
#ifndef PACK_REVINDEX_H
|
|
#define PACK_REVINDEX_H
|
|
|
|
/**
|
|
* A revindex allows converting efficiently between three properties
|
|
* of an object within a pack:
|
|
*
|
|
* - index position: the numeric position within the list of sorted object ids
|
|
* found in the .idx file
|
|
*
|
|
* - pack position: the numeric position within the list of objects in their
|
|
* order within the actual .pack file (i.e., 0 is the first object in the
|
|
* .pack, 1 is the second, and so on)
|
|
*
|
|
* - offset: the byte offset within the .pack file at which the object contents
|
|
* can be found
|
|
*
|
|
* The revindex can also be used with a multi-pack index (MIDX). In this
|
|
* setting:
|
|
*
|
|
* - index position refers to an object's numeric position within the MIDX
|
|
*
|
|
* - pack position refers to an object's position within a non-existent pack
|
|
* described by the MIDX. The pack structure is described in
|
|
* Documentation/technical/pack-format.txt.
|
|
*
|
|
* It is effectively a concatanation of all packs in the MIDX (ordered by
|
|
* their numeric ID within the MIDX) in their original order within each
|
|
* pack), removing duplicates, and placing the preferred pack (if any)
|
|
* first.
|
|
*/
|
|
|
|
|
|
#define RIDX_SIGNATURE 0x52494458 /* "RIDX" */
|
|
#define RIDX_VERSION 1
|
|
|
|
#define GIT_TEST_WRITE_REV_INDEX "GIT_TEST_WRITE_REV_INDEX"
|
|
#define GIT_TEST_REV_INDEX_DIE_IN_MEMORY "GIT_TEST_REV_INDEX_DIE_IN_MEMORY"
|
|
|
|
struct packed_git;
|
|
struct multi_pack_index;
|
|
|
|
/*
|
|
* load_pack_revindex populates the revindex's internal data-structures for the
|
|
* given pack, returning zero on success and a negative value otherwise.
|
|
*
|
|
* If a '.rev' file is present it is mmap'd, and pointers are assigned into it
|
|
* (instead of using the in-memory variant).
|
|
*/
|
|
int load_pack_revindex(struct packed_git *p);
|
|
|
|
/*
|
|
* load_midx_revindex loads the '.rev' file corresponding to the given
|
|
* multi-pack index by mmap-ing it and assigning pointers in the
|
|
* multi_pack_index to point at it.
|
|
*
|
|
* A negative number is returned on error.
|
|
*/
|
|
int load_midx_revindex(struct multi_pack_index *m);
|
|
|
|
/*
|
|
* Frees resources associated with a multi-pack reverse index.
|
|
*
|
|
* A negative number is returned on error.
|
|
*/
|
|
int close_midx_revindex(struct multi_pack_index *m);
|
|
|
|
/*
|
|
* offset_to_pack_pos converts an object offset to a pack position. This
|
|
* function returns zero on success, and a negative number otherwise. The
|
|
* parameter 'pos' is usable only on success.
|
|
*
|
|
* If the reverse index has not yet been loaded, this function loads it lazily,
|
|
* and returns an negative number if an error was encountered.
|
|
*
|
|
* This function runs in time O(log N) with the number of objects in the pack.
|
|
*/
|
|
int offset_to_pack_pos(struct packed_git *p, off_t ofs, uint32_t *pos);
|
|
|
|
/*
|
|
* pack_pos_to_index converts the given pack-relative position 'pos' by
|
|
* returning an index-relative position.
|
|
*
|
|
* If the reverse index has not yet been loaded, or the position is out of
|
|
* bounds, this function aborts.
|
|
*
|
|
* This function runs in constant time.
|
|
*/
|
|
uint32_t pack_pos_to_index(struct packed_git *p, uint32_t pos);
|
|
|
|
/*
|
|
* pack_pos_to_offset converts the given pack-relative position 'pos' into a
|
|
* pack offset. For a pack with 'N' objects, asking for position 'N' will return
|
|
* the total size (in bytes) of the pack.
|
|
*
|
|
* If the reverse index has not yet been loaded, or the position is out of
|
|
* bounds, this function aborts.
|
|
*
|
|
* This function runs in constant time under both in-memory and on-disk reverse
|
|
* indexes, but an additional step is taken to consult the corresponding .idx
|
|
* file when using the on-disk format.
|
|
*/
|
|
off_t pack_pos_to_offset(struct packed_git *p, uint32_t pos);
|
|
|
|
/*
|
|
* pack_pos_to_midx converts the object at position "pos" within the MIDX
|
|
* pseudo-pack into a MIDX position.
|
|
*
|
|
* If the reverse index has not yet been loaded, or the position is out of
|
|
* bounds, this function aborts.
|
|
*
|
|
* This function runs in constant time.
|
|
*/
|
|
uint32_t pack_pos_to_midx(struct multi_pack_index *m, uint32_t pos);
|
|
|
|
/*
|
|
* midx_to_pack_pos converts from the MIDX-relative position at "at" to the
|
|
* corresponding pack position.
|
|
*
|
|
* If the reverse index has not yet been loaded, or the position is out of
|
|
* bounds, this function aborts.
|
|
*
|
|
* This function runs in time O(log N) with the number of objects in the MIDX.
|
|
*/
|
|
int midx_to_pack_pos(struct multi_pack_index *midx, uint32_t at, uint32_t *pos);
|
|
|
|
#endif
|