diff options
Diffstat (limited to 'midx.c')
| -rw-r--r-- | midx.c | 930 |
1 files changed, 930 insertions, 0 deletions
@@ -0,0 +1,930 @@ +#include "cache.h" +#include "config.h" +#include "csum-file.h" +#include "dir.h" +#include "lockfile.h" +#include "packfile.h" +#include "object-store.h" +#include "sha1-lookup.h" +#include "midx.h" + +#define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */ +#define MIDX_VERSION 1 +#define MIDX_BYTE_FILE_VERSION 4 +#define MIDX_BYTE_HASH_VERSION 5 +#define MIDX_BYTE_NUM_CHUNKS 6 +#define MIDX_BYTE_NUM_PACKS 8 +#define MIDX_HASH_VERSION 1 +#define MIDX_HEADER_SIZE 12 +#define MIDX_HASH_LEN 20 +#define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + MIDX_HASH_LEN) + +#define MIDX_MAX_CHUNKS 5 +#define MIDX_CHUNK_ALIGNMENT 4 +#define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */ +#define MIDX_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */ +#define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */ +#define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */ +#define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */ +#define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t)) +#define MIDX_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256) +#define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t)) +#define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t)) +#define MIDX_LARGE_OFFSET_NEEDED 0x80000000 + +static char *get_midx_filename(const char *object_dir) +{ + return xstrfmt("%s/pack/multi-pack-index", object_dir); +} + +struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local) +{ + struct multi_pack_index *m = NULL; + int fd; + struct stat st; + size_t midx_size; + void *midx_map = NULL; + uint32_t hash_version; + char *midx_name = get_midx_filename(object_dir); + uint32_t i; + const char *cur_pack_name; + + fd = git_open(midx_name); + + if (fd < 0) + goto cleanup_fail; + if (fstat(fd, &st)) { + error_errno(_("failed to read %s"), midx_name); + goto cleanup_fail; + } + + midx_size = xsize_t(st.st_size); + + if (midx_size < MIDX_MIN_SIZE) { + error(_("multi-pack-index file %s is too small"), midx_name); + goto cleanup_fail; + } + + FREE_AND_NULL(midx_name); + + midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0); + + FLEX_ALLOC_MEM(m, object_dir, object_dir, strlen(object_dir)); + m->fd = fd; + m->data = midx_map; + m->data_len = midx_size; + m->local = local; + + m->signature = get_be32(m->data); + if (m->signature != MIDX_SIGNATURE) { + error(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"), + m->signature, MIDX_SIGNATURE); + goto cleanup_fail; + } + + m->version = m->data[MIDX_BYTE_FILE_VERSION]; + if (m->version != MIDX_VERSION) { + error(_("multi-pack-index version %d not recognized"), + m->version); + goto cleanup_fail; + } + + hash_version = m->data[MIDX_BYTE_HASH_VERSION]; + if (hash_version != MIDX_HASH_VERSION) { + error(_("hash version %u does not match"), hash_version); + goto cleanup_fail; + } + m->hash_len = MIDX_HASH_LEN; + + m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS]; + + m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS); + + for (i = 0; i < m->num_chunks; i++) { + uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE + + MIDX_CHUNKLOOKUP_WIDTH * i); + uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 + + MIDX_CHUNKLOOKUP_WIDTH * i); + + switch (chunk_id) { + case MIDX_CHUNKID_PACKNAMES: + m->chunk_pack_names = m->data + chunk_offset; + break; + + case MIDX_CHUNKID_OIDFANOUT: + m->chunk_oid_fanout = (uint32_t *)(m->data + chunk_offset); + break; + + case MIDX_CHUNKID_OIDLOOKUP: + m->chunk_oid_lookup = m->data + chunk_offset; + break; + + case MIDX_CHUNKID_OBJECTOFFSETS: + m->chunk_object_offsets = m->data + chunk_offset; + break; + + case MIDX_CHUNKID_LARGEOFFSETS: + m->chunk_large_offsets = m->data + chunk_offset; + break; + + case 0: + die(_("terminating multi-pack-index chunk id appears earlier than expected")); + break; + + default: + /* + * Do nothing on unrecognized chunks, allowing future + * extensions to add optional chunks. + */ + break; + } + } + + if (!m->chunk_pack_names) + die(_("multi-pack-index missing required pack-name chunk")); + if (!m->chunk_oid_fanout) + die(_("multi-pack-index missing required OID fanout chunk")); + if (!m->chunk_oid_lookup) + die(_("multi-pack-index missing required OID lookup chunk")); + if (!m->chunk_object_offsets) + die(_("multi-pack-index missing required object offsets chunk")); + + m->num_objects = ntohl(m->chunk_oid_fanout[255]); + + m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names)); + m->packs = xcalloc(m->num_packs, sizeof(*m->packs)); + + cur_pack_name = (const char *)m->chunk_pack_names; + for (i = 0; i < m->num_packs; i++) { + m->pack_names[i] = cur_pack_name; + + cur_pack_name += strlen(cur_pack_name) + 1; + + if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0) { + error(_("multi-pack-index pack names out of order: '%s' before '%s'"), + m->pack_names[i - 1], + m->pack_names[i]); + goto cleanup_fail; + } + } + + return m; + +cleanup_fail: + free(m); + free(midx_name); + if (midx_map) + munmap(midx_map, midx_size); + if (0 <= fd) + close(fd); + return NULL; +} + +static void close_midx(struct multi_pack_index *m) +{ + uint32_t i; + munmap((unsigned char *)m->data, m->data_len); + close(m->fd); + m->fd = -1; + + for (i = 0; i < m->num_packs; i++) { + if (m->packs[i]) { + close_pack(m->packs[i]); + free(m->packs); + } + } + FREE_AND_NULL(m->packs); + FREE_AND_NULL(m->pack_names); +} + +int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id) +{ + struct strbuf pack_name = STRBUF_INIT; + + if (pack_int_id >= m->num_packs) + BUG("bad pack-int-id"); + + if (m->packs[pack_int_id]) + return 0; + + strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir, + m->pack_names[pack_int_id]); + + m->packs[pack_int_id] = add_packed_git(pack_name.buf, pack_name.len, m->local); + strbuf_release(&pack_name); + return !m->packs[pack_int_id]; +} + +int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result) +{ + return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup, + MIDX_HASH_LEN, result); +} + +struct object_id *nth_midxed_object_oid(struct object_id *oid, + struct multi_pack_index *m, + uint32_t n) +{ + if (n >= m->num_objects) + return NULL; + + hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n); + return oid; +} + +static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos) +{ + const unsigned char *offset_data; + uint32_t offset32; + + offset_data = m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH; + offset32 = get_be32(offset_data + sizeof(uint32_t)); + + if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) { + if (sizeof(offset32) < sizeof(uint64_t)) + die(_("multi-pack-index stores a 64-bit offset, but off_t is too small")); + + offset32 ^= MIDX_LARGE_OFFSET_NEEDED; + return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32); + } + + return offset32; +} + +static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos) +{ + return get_be32(m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH); +} + +static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *e, uint32_t pos) +{ + uint32_t pack_int_id; + struct packed_git *p; + + if (pos >= m->num_objects) + return 0; + + pack_int_id = nth_midxed_pack_int_id(m, pos); + + if (prepare_midx_pack(m, pack_int_id)) + die(_("error preparing packfile from multi-pack-index")); + p = m->packs[pack_int_id]; + + /* + * We are about to tell the caller where they can locate the + * requested object. We better make sure the packfile is + * still here and can be accessed before supplying that + * answer, as it may have been deleted since the MIDX was + * loaded! + */ + if (!is_pack_valid(p)) + return 0; + + if (p->num_bad_objects) { + uint32_t i; + struct object_id oid; + nth_midxed_object_oid(&oid, m, pos); + for (i = 0; i < p->num_bad_objects; i++) + if (!hashcmp(oid.hash, + p->bad_object_sha1 + the_hash_algo->rawsz * i)) + return 0; + } + + e->offset = nth_midxed_offset(m, pos); + e->p = p; + + return 1; +} + +int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m) +{ + uint32_t pos; + + if (!bsearch_midx(oid, m, &pos)) + return 0; + + return nth_midxed_pack_entry(m, e, pos); +} + +int midx_contains_pack(struct multi_pack_index *m, const char *idx_name) +{ + uint32_t first = 0, last = m->num_packs; + + while (first < last) { + uint32_t mid = first + (last - first) / 2; + const char *current; + int cmp; + + current = m->pack_names[mid]; + cmp = strcmp(idx_name, current); + if (!cmp) + return 1; + if (cmp > 0) { + first = mid + 1; + continue; + } + last = mid; + } + + return 0; +} + +int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local) +{ + struct multi_pack_index *m; + struct multi_pack_index *m_search; + int config_value; + + if (repo_config_get_bool(r, "core.multipackindex", &config_value) || + !config_value) + return 0; + + for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next) + if (!strcmp(object_dir, m_search->object_dir)) + return 1; + + m = load_multi_pack_index(object_dir, local); + + if (m) { + m->next = r->objects->multi_pack_index; + r->objects->multi_pack_index = m; + return 1; + } + + return 0; +} + +static size_t write_midx_header(struct hashfile *f, + unsigned char num_chunks, + uint32_t num_packs) +{ + unsigned char byte_values[4]; + + hashwrite_be32(f, MIDX_SIGNATURE); + byte_values[0] = MIDX_VERSION; + byte_values[1] = MIDX_HASH_VERSION; + byte_values[2] = num_chunks; + byte_values[3] = 0; /* unused */ + hashwrite(f, byte_values, sizeof(byte_values)); + hashwrite_be32(f, num_packs); + + return MIDX_HEADER_SIZE; +} + +struct pack_list { + struct packed_git **list; + char **names; + uint32_t nr; + uint32_t alloc_list; + uint32_t alloc_names; + size_t pack_name_concat_len; + struct multi_pack_index *m; +}; + +static void add_pack_to_midx(const char *full_path, size_t full_path_len, + const char *file_name, void *data) +{ + struct pack_list *packs = (struct pack_list *)data; + + if (ends_with(file_name, ".idx")) { + if (packs->m && midx_contains_pack(packs->m, file_name)) + return; + + ALLOC_GROW(packs->list, packs->nr + 1, packs->alloc_list); + ALLOC_GROW(packs->names, packs->nr + 1, packs->alloc_names); + + packs->list[packs->nr] = add_packed_git(full_path, + full_path_len, + 0); + + if (!packs->list[packs->nr]) { + warning(_("failed to add packfile '%s'"), + full_path); + return; + } + + if (open_pack_index(packs->list[packs->nr])) { + warning(_("failed to open pack-index '%s'"), + full_path); + close_pack(packs->list[packs->nr]); + FREE_AND_NULL(packs->list[packs->nr]); + return; + } + + packs->names[packs->nr] = xstrdup(file_name); + packs->pack_name_concat_len += strlen(file_name) + 1; + packs->nr++; + } +} + +struct pack_pair { + uint32_t pack_int_id; + char *pack_name; +}; + +static int pack_pair_compare(const void *_a, const void *_b) +{ + struct pack_pair *a = (struct pack_pair *)_a; + struct pack_pair *b = (struct pack_pair *)_b; + return strcmp(a->pack_name, b->pack_name); +} + +static void sort_packs_by_name(char **pack_names, uint32_t nr_packs, uint32_t *perm) +{ + uint32_t i; + struct pack_pair *pairs; + + ALLOC_ARRAY(pairs, nr_packs); + + for (i = 0; i < nr_packs; i++) { + pairs[i].pack_int_id = i; + pairs[i].pack_name = pack_names[i]; + } + + QSORT(pairs, nr_packs, pack_pair_compare); + + for (i = 0; i < nr_packs; i++) { + pack_names[i] = pairs[i].pack_name; + perm[pairs[i].pack_int_id] = i; + } + + free(pairs); +} + +struct pack_midx_entry { + struct object_id oid; + uint32_t pack_int_id; + time_t pack_mtime; + uint64_t offset; +}; + +static int midx_oid_compare(const void *_a, const void *_b) +{ + const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a; + const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b; + int cmp = oidcmp(&a->oid, &b->oid); + + if (cmp) + return cmp; + + if (a->pack_mtime > b->pack_mtime) + return -1; + else if (a->pack_mtime < b->pack_mtime) + return 1; + + return a->pack_int_id - b->pack_int_id; +} + +static int nth_midxed_pack_midx_entry(struct multi_pack_index *m, + uint32_t *pack_perm, + struct pack_midx_entry *e, + uint32_t pos) +{ + if (pos >= m->num_objects) + return 1; + + nth_midxed_object_oid(&e->oid, m, pos); + e->pack_int_id = pack_perm[nth_midxed_pack_int_id(m, pos)]; + e->offset = nth_midxed_offset(m, pos); + + /* consider objects in midx to be from "old" packs */ + e->pack_mtime = 0; + return 0; +} + +static void fill_pack_entry(uint32_t pack_int_id, + struct packed_git *p, + uint32_t cur_object, + struct pack_midx_entry *entry) +{ + if (!nth_packed_object_oid(&entry->oid, p, cur_object)) + die(_("failed to locate object %d in packfile"), cur_object); + + entry->pack_int_id = pack_int_id; + entry->pack_mtime = p->mtime; + + entry->offset = nth_packed_object_offset(p, cur_object); +} + +/* + * It is possible to artificially get into a state where there are many + * duplicate copies of objects. That can create high memory pressure if + * we are to create a list of all objects before de-duplication. To reduce + * this memory pressure without a significant performance drop, automatically + * group objects by the first byte of their object id. Use the IDX fanout + * tables to group the data, copy to a local array, then sort. + * + * Copy only the de-duplicated entries (selected by most-recent modified time + * of a packfile containing the object). + */ +static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m, + struct packed_git **p, + uint32_t *perm, + uint32_t nr_packs, + uint32_t *nr_objects) +{ + uint32_t cur_fanout, cur_pack, cur_object; + uint32_t alloc_fanout, alloc_objects, total_objects = 0; + struct pack_midx_entry *entries_by_fanout = NULL; + struct pack_midx_entry *deduplicated_entries = NULL; + uint32_t start_pack = m ? m->num_packs : 0; + + for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) + total_objects += p[cur_pack]->num_objects; + + /* + * As we de-duplicate by fanout value, we expect the fanout + * slices to be evenly distributed, with some noise. Hence, + * allocate slightly more than one 256th. + */ + alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16; + + ALLOC_ARRAY(entries_by_fanout, alloc_fanout); + ALLOC_ARRAY(deduplicated_entries, alloc_objects); + *nr_objects = 0; + + for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) { + uint32_t nr_fanout = 0; + + if (m) { + uint32_t start = 0, end; + + if (cur_fanout) + start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]); + end = ntohl(m->chunk_oid_fanout[cur_fanout]); + + for (cur_object = start; cur_object < end; cur_object++) { + ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout); + nth_midxed_pack_midx_entry(m, perm, + &entries_by_fanout[nr_fanout], + cur_object); + nr_fanout++; + } + } + + for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) { + uint32_t start = 0, end; + + if (cur_fanout) + start = get_pack_fanout(p[cur_pack], cur_fanout - 1); + end = get_pack_fanout(p[cur_pack], cur_fanout); + + for (cur_object = start; cur_object < end; cur_object++) { + ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout); + fill_pack_entry(perm[cur_pack], p[cur_pack], cur_object, &entries_by_fanout[nr_fanout]); + nr_fanout++; + } + } + + QSORT(entries_by_fanout, nr_fanout, midx_oid_compare); + + /* + * The batch is now sorted by OID and then mtime (descending). + * Take only the first duplicate. + */ + for (cur_object = 0; cur_object < nr_fanout; cur_object++) { + if (cur_object && !oidcmp(&entries_by_fanout[cur_object - 1].oid, + &entries_by_fanout[cur_object].oid)) + continue; + + ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects); + memcpy(&deduplicated_entries[*nr_objects], + &entries_by_fanout[cur_object], + sizeof(struct pack_midx_entry)); + (*nr_objects)++; + } + } + + free(entries_by_fanout); + return deduplicated_entries; +} + +static size_t write_midx_pack_names(struct hashfile *f, + char **pack_names, + uint32_t num_packs) +{ + uint32_t i; + unsigned char padding[MIDX_CHUNK_ALIGNMENT]; + size_t written = 0; + + for (i = 0; i < num_packs; i++) { + size_t writelen = strlen(pack_names[i]) + 1; + + if (i && strcmp(pack_names[i], pack_names[i - 1]) <= 0) + BUG("incorrect pack-file order: %s before %s", + pack_names[i - 1], + pack_names[i]); + + hashwrite(f, pack_names[i], writelen); + written += writelen; + } + + /* add padding to be aligned */ + i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT); + if (i < MIDX_CHUNK_ALIGNMENT) { + memset(padding, 0, sizeof(padding)); + hashwrite(f, padding, i); + written += i; + } + + return written; +} + +static size_t write_midx_oid_fanout(struct hashfile *f, + struct pack_midx_entry *objects, + uint32_t nr_objects) +{ + struct pack_midx_entry *list = objects; + struct pack_midx_entry *last = objects + nr_objects; + uint32_t count = 0; + uint32_t i; + + /* + * Write the first-level table (the list is sorted, + * but we use a 256-entry lookup to be able to avoid + * having to do eight extra binary search iterations). + */ + for (i = 0; i < 256; i++) { + struct pack_midx_entry *next = list; + + while (next < last && next->oid.hash[0] == i) { + count++; + next++; + } + + hashwrite_be32(f, count); + list = next; + } + + return MIDX_CHUNK_FANOUT_SIZE; +} + +static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len, + struct pack_midx_entry *objects, + uint32_t nr_objects) +{ + struct pack_midx_entry *list = objects; + uint32_t i; + size_t written = 0; + + for (i = 0; i < nr_objects; i++) { + struct pack_midx_entry *obj = list++; + + if (i < nr_objects - 1) { + struct pack_midx_entry *next = list; + if (oidcmp(&obj->oid, &next->oid) >= 0) + BUG("OIDs not in order: %s >= %s", + oid_to_hex(&obj->oid), + oid_to_hex(&next->oid)); + } + + hashwrite(f, obj->oid.hash, (int)hash_len); + written += hash_len; + } + + return written; +} + +static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed, + struct pack_midx_entry *objects, uint32_t nr_objects) +{ + struct pack_midx_entry *list = objects; + uint32_t i, nr_large_offset = 0; + size_t written = 0; + + for (i = 0; i < nr_objects; i++) { + struct pack_midx_entry *obj = list++; + + hashwrite_be32(f, obj->pack_int_id); + + if (large_offset_needed && obj->offset >> 31) + hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++); + else if (!large_offset_needed && obj->offset >> 32) + BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!", + oid_to_hex(&obj->oid), + obj->offset); + else + hashwrite_be32(f, (uint32_t)obj->offset); + + written += MIDX_CHUNK_OFFSET_WIDTH; + } + + return written; +} + +static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset, + struct pack_midx_entry *objects, uint32_t nr_objects) +{ + struct pack_midx_entry *list = objects; + size_t written = 0; + + while (nr_large_offset) { + struct pack_midx_entry *obj = list++; + uint64_t offset = obj->offset; + + if (!(offset >> 31)) + continue; + + hashwrite_be32(f, offset >> 32); + hashwrite_be32(f, offset & 0xffffffffUL); + written += 2 * sizeof(uint32_t); + + nr_large_offset--; + } + + return written; +} + +int write_midx_file(const char *object_dir) +{ + unsigned char cur_chunk, num_chunks = 0; + char *midx_name; + uint32_t i; + struct hashfile *f = NULL; + struct lock_file lk; + struct pack_list packs; + uint32_t *pack_perm = NULL; + uint64_t written = 0; + uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1]; + uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1]; + uint32_t nr_entries, num_large_offsets = 0; + struct pack_midx_entry *entries = NULL; + int large_offsets_needed = 0; + + midx_name = get_midx_filename(object_dir); + if (safe_create_leading_directories(midx_name)) { + UNLEAK(midx_name); + die_errno(_("unable to create leading directories of %s"), + midx_name); + } + + packs.m = load_multi_pack_index(object_dir, 1); + + packs.nr = 0; + packs.alloc_list = packs.m ? packs.m->num_packs : 16; + packs.alloc_names = packs.alloc_list; + packs.list = NULL; + packs.names = NULL; + packs.pack_name_concat_len = 0; + ALLOC_ARRAY(packs.list, packs.alloc_list); + ALLOC_ARRAY(packs.names, packs.alloc_names); + + if (packs.m) { + for (i = 0; i < packs.m->num_packs; i++) { + ALLOC_GROW(packs.list, packs.nr + 1, packs.alloc_list); + ALLOC_GROW(packs.names, packs.nr + 1, packs.alloc_names); + + packs.list[packs.nr] = NULL; + packs.names[packs.nr] = xstrdup(packs.m->pack_names[i]); + packs.pack_name_concat_len += strlen(packs.names[packs.nr]) + 1; + packs.nr++; + } + } + + for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs); + + if (packs.m && packs.nr == packs.m->num_packs) + goto cleanup; + + if (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT) + packs.pack_name_concat_len += MIDX_CHUNK_ALIGNMENT - + (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT); + + ALLOC_ARRAY(pack_perm, packs.nr); + sort_packs_by_name(packs.names, packs.nr, pack_perm); + + entries = get_sorted_entries(packs.m, packs.list, pack_perm, packs.nr, &nr_entries); + + for (i = 0; i < nr_entries; i++) { + if (entries[i].offset > 0x7fffffff) + num_large_offsets++; + if (entries[i].offset > 0xffffffff) + large_offsets_needed = 1; + } + + hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR); + f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf); + FREE_AND_NULL(midx_name); + + if (packs.m) + close_midx(packs.m); + + cur_chunk = 0; + num_chunks = large_offsets_needed ? 5 : 4; + + written = write_midx_header(f, num_chunks, packs.nr); + + chunk_ids[cur_chunk] = MIDX_CHUNKID_PACKNAMES; + chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH; + + cur_chunk++; + chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDFANOUT; + chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + packs.pack_name_concat_len; + + cur_chunk++; + chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP; + chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + MIDX_CHUNK_FANOUT_SIZE; + + cur_chunk++; + chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS; + chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_HASH_LEN; + + cur_chunk++; + chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH; + if (large_offsets_needed) { + chunk_ids[cur_chunk] = MIDX_CHUNKID_LARGEOFFSETS; + + cur_chunk++; + chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + + num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH; + } + + chunk_ids[cur_chunk] = 0; + + for (i = 0; i <= num_chunks; i++) { + if (i && chunk_offsets[i] < chunk_offsets[i - 1]) + BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64, + chunk_offsets[i - 1], + chunk_offsets[i]); + + if (chunk_offsets[i] % MIDX_CHUNK_ALIGNMENT) + BUG("chunk offset %"PRIu64" is not properly aligned", + chunk_offsets[i]); + + hashwrite_be32(f, chunk_ids[i]); + hashwrite_be32(f, chunk_offsets[i] >> 32); + hashwrite_be32(f, chunk_offsets[i]); + + written += MIDX_CHUNKLOOKUP_WIDTH; + } + + for (i = 0; i < num_chunks; i++) { + if (written != chunk_offsets[i]) + BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32, + chunk_offsets[i], + written, + chunk_ids[i]); + + switch (chunk_ids[i]) { + case MIDX_CHUNKID_PACKNAMES: + written += write_midx_pack_names(f, packs.names, packs.nr); + break; + + case MIDX_CHUNKID_OIDFANOUT: + written += write_midx_oid_fanout(f, entries, nr_entries); + break; + + case MIDX_CHUNKID_OIDLOOKUP: + written += write_midx_oid_lookup(f, MIDX_HASH_LEN, entries, nr_entries); + break; + + case MIDX_CHUNKID_OBJECTOFFSETS: + written += write_midx_object_offsets(f, large_offsets_needed, entries, nr_entries); + break; + + case MIDX_CHUNKID_LARGEOFFSETS: + written += write_midx_large_offsets(f, num_large_offsets, entries, nr_entries); + break; + + default: + BUG("trying to write unknown chunk id %"PRIx32, + chunk_ids[i]); + } + } + + if (written != chunk_offsets[num_chunks]) + BUG("incorrect final offset %"PRIu64" != %"PRIu64, + written, + chunk_offsets[num_chunks]); + + finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM); + commit_lock_file(&lk); + +cleanup: + for (i = 0; i < packs.nr; i++) { + if (packs.list[i]) { + close_pack(packs.list[i]); + free(packs.list[i]); + } + free(packs.names[i]); + } + + free(packs.list); + free(packs.names); + free(entries); + free(pack_perm); + free(midx_name); + return 0; +} + +void clear_midx_file(const char *object_dir) +{ + char *midx = get_midx_filename(object_dir); + + if (remove_path(midx)) { + UNLEAK(midx); + die(_("failed to clear multi-pack-index at %s"), midx); + } + + free(midx); +} |