diff options
Diffstat (limited to 'pack-revindex.c')
| -rw-r--r-- | pack-revindex.c | 187 |
1 files changed, 165 insertions, 22 deletions
diff --git a/pack-revindex.c b/pack-revindex.c index ecdde39cf4..83fe4de773 100644 --- a/pack-revindex.c +++ b/pack-revindex.c @@ -2,6 +2,12 @@ #include "pack-revindex.h" #include "object-store.h" #include "packfile.h" +#include "config.h" + +struct revindex_entry { + off_t offset; + unsigned int nr; +}; /* * Pack index for existing packs give us easy access to the offsets into @@ -159,27 +165,151 @@ static void create_pack_revindex(struct packed_git *p) sort_revindex(p->revindex, num_ent, p->pack_size); } -int load_pack_revindex(struct packed_git *p) +static int create_pack_revindex_in_memory(struct packed_git *p) { - if (!p->revindex) { - if (open_pack_index(p)) - return -1; - create_pack_revindex(p); - } + if (git_env_bool(GIT_TEST_REV_INDEX_DIE_IN_MEMORY, 0)) + die("dying as requested by '%s'", + GIT_TEST_REV_INDEX_DIE_IN_MEMORY); + if (open_pack_index(p)) + return -1; + create_pack_revindex(p); return 0; } -int find_revindex_position(struct packed_git *p, off_t ofs) +static char *pack_revindex_filename(struct packed_git *p) +{ + size_t len; + if (!strip_suffix(p->pack_name, ".pack", &len)) + BUG("pack_name does not end in .pack"); + return xstrfmt("%.*s.rev", (int)len, p->pack_name); +} + +#define RIDX_HEADER_SIZE (12) +#define RIDX_MIN_SIZE (RIDX_HEADER_SIZE + (2 * the_hash_algo->rawsz)) + +struct revindex_header { + uint32_t signature; + uint32_t version; + uint32_t hash_id; +}; + +static int load_revindex_from_disk(char *revindex_name, + uint32_t num_objects, + const uint32_t **data_p, size_t *len_p) +{ + int fd, ret = 0; + struct stat st; + void *data = NULL; + size_t revindex_size; + struct revindex_header *hdr; + + fd = git_open(revindex_name); + + if (fd < 0) { + ret = -1; + goto cleanup; + } + if (fstat(fd, &st)) { + ret = error_errno(_("failed to read %s"), revindex_name); + goto cleanup; + } + + revindex_size = xsize_t(st.st_size); + + if (revindex_size < RIDX_MIN_SIZE) { + ret = error(_("reverse-index file %s is too small"), revindex_name); + goto cleanup; + } + + if (revindex_size - RIDX_MIN_SIZE != st_mult(sizeof(uint32_t), num_objects)) { + ret = error(_("reverse-index file %s is corrupt"), revindex_name); + goto cleanup; + } + + data = xmmap(NULL, revindex_size, PROT_READ, MAP_PRIVATE, fd, 0); + hdr = data; + + if (ntohl(hdr->signature) != RIDX_SIGNATURE) { + ret = error(_("reverse-index file %s has unknown signature"), revindex_name); + goto cleanup; + } + if (ntohl(hdr->version) != 1) { + ret = error(_("reverse-index file %s has unsupported version %"PRIu32), + revindex_name, ntohl(hdr->version)); + goto cleanup; + } + if (!(ntohl(hdr->hash_id) == 1 || ntohl(hdr->hash_id) == 2)) { + ret = error(_("reverse-index file %s has unsupported hash id %"PRIu32), + revindex_name, ntohl(hdr->hash_id)); + goto cleanup; + } + +cleanup: + if (ret) { + if (data) + munmap(data, revindex_size); + } else { + *len_p = revindex_size; + *data_p = (const uint32_t *)data; + } + + close(fd); + return ret; +} + +static int load_pack_revindex_from_disk(struct packed_git *p) +{ + char *revindex_name; + int ret; + if (open_pack_index(p)) + return -1; + + revindex_name = pack_revindex_filename(p); + + ret = load_revindex_from_disk(revindex_name, + p->num_objects, + &p->revindex_map, + &p->revindex_size); + if (ret) + goto cleanup; + + p->revindex_data = (const uint32_t *)((const char *)p->revindex_map + RIDX_HEADER_SIZE); + +cleanup: + free(revindex_name); + return ret; +} + +int load_pack_revindex(struct packed_git *p) +{ + if (p->revindex || p->revindex_data) + return 0; + + if (!load_pack_revindex_from_disk(p)) + return 0; + else if (!create_pack_revindex_in_memory(p)) + return 0; + return -1; +} + +int offset_to_pack_pos(struct packed_git *p, off_t ofs, uint32_t *pos) { - int lo = 0; - int hi = p->num_objects + 1; - const struct revindex_entry *revindex = p->revindex; + unsigned lo, hi; + + if (load_pack_revindex(p) < 0) + return -1; + + lo = 0; + hi = p->num_objects + 1; do { const unsigned mi = lo + (hi - lo) / 2; - if (revindex[mi].offset == ofs) { - return mi; - } else if (ofs < revindex[mi].offset) + off_t got = pack_pos_to_offset(p, mi); + + if (got == ofs) { + *pos = mi; + return 0; + } else if (ofs < got) hi = mi; else lo = mi + 1; @@ -189,17 +319,30 @@ int find_revindex_position(struct packed_git *p, off_t ofs) return -1; } -struct revindex_entry *find_pack_revindex(struct packed_git *p, off_t ofs) +uint32_t pack_pos_to_index(struct packed_git *p, uint32_t pos) { - int pos; + if (!(p->revindex || p->revindex_data)) + BUG("pack_pos_to_index: reverse index not yet loaded"); + if (p->num_objects <= pos) + BUG("pack_pos_to_index: out-of-bounds object at %"PRIu32, pos); - if (load_pack_revindex(p)) - return NULL; - - pos = find_revindex_position(p, ofs); + if (p->revindex) + return p->revindex[pos].nr; + else + return get_be32(p->revindex_data + pos); +} - if (pos < 0) - return NULL; +off_t pack_pos_to_offset(struct packed_git *p, uint32_t pos) +{ + if (!(p->revindex || p->revindex_data)) + BUG("pack_pos_to_index: reverse index not yet loaded"); + if (p->num_objects < pos) + BUG("pack_pos_to_offset: out-of-bounds object at %"PRIu32, pos); - return p->revindex + pos; + if (p->revindex) + return p->revindex[pos].offset; + else if (pos == p->num_objects) + return p->pack_size - the_hash_algo->rawsz; + else + return nth_packed_object_offset(p, pack_pos_to_index(p, pos)); } |