#define MIDX_HASH_LEN 20
#define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + MIDX_HASH_LEN)
+#define MIDX_MAX_CHUNKS 1
+#define MIDX_CHUNK_ALIGNMENT 4
+#define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
+#define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
+
static char *get_midx_filename(const char *object_dir)
{
return xstrfmt("%s/pack/multi-pack-index", object_dir);
void *midx_map = NULL;
uint32_t hash_version;
char *midx_name = get_midx_filename(object_dir);
+ uint32_t i;
fd = git_open(midx_name);
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 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"));
+
return m;
cleanup_fail:
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;
};
static void add_pack_to_midx(const char *full_path, size_t full_path_len,
if (ends_with(file_name, ".idx")) {
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,
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);
+}
+
+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;
+}
+
int write_midx_file(const char *object_dir)
{
- unsigned char num_chunks = 0;
+ 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];
midx_name = get_midx_filename(object_dir);
if (safe_create_leading_directories(midx_name)) {
packs.nr = 0;
packs.alloc_list = 16;
+ packs.alloc_names = 16;
packs.list = NULL;
+ packs.pack_name_concat_len = 0;
ALLOC_ARRAY(packs.list, packs.alloc_list);
+ ALLOC_ARRAY(packs.names, packs.alloc_names);
for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
+ 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);
+
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);
- write_midx_header(f, num_chunks, packs.nr);
+ cur_chunk = 0;
+ num_chunks = 1;
+
+ 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] = 0;
+ chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + packs.pack_name_concat_len;
+
+ 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;
+
+ 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);
close_pack(packs.list[i]);
free(packs.list[i]);
}
+ free(packs.names[i]);
}
free(packs.list);
+ free(packs.names);
return 0;
}