| #include "cache.h" |
| #include "object.h" |
| #include "delta.h" |
| #include "pack.h" |
| #include "csum-file.h" |
| |
| static const char pack_usage[] = "git-pack-objects [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list"; |
| |
| struct object_entry { |
| unsigned char sha1[20]; |
| unsigned long size; |
| unsigned long offset; |
| unsigned int depth; |
| unsigned int hash; |
| enum object_type type; |
| unsigned long delta_size; |
| struct object_entry *delta; |
| }; |
| |
| static unsigned char object_list_sha1[20]; |
| static int non_empty = 0; |
| static int local = 0; |
| static int incremental = 0; |
| static struct object_entry **sorted_by_sha, **sorted_by_type; |
| static struct object_entry *objects = NULL; |
| static int nr_objects = 0, nr_alloc = 0; |
| static const char *base_name; |
| static unsigned char pack_file_sha1[20]; |
| |
| static void *delta_against(void *buf, unsigned long size, struct object_entry *entry) |
| { |
| unsigned long othersize, delta_size; |
| char type[10]; |
| void *otherbuf = read_sha1_file(entry->delta->sha1, type, &othersize); |
| void *delta_buf; |
| |
| if (!otherbuf) |
| die("unable to read %s", sha1_to_hex(entry->delta->sha1)); |
| delta_buf = diff_delta(otherbuf, othersize, |
| buf, size, &delta_size, 0); |
| if (!delta_buf || delta_size != entry->delta_size) |
| die("delta size changed"); |
| free(buf); |
| free(otherbuf); |
| return delta_buf; |
| } |
| |
| /* |
| * The per-object header is a pretty dense thing, which is |
| * - first byte: low four bits are "size", then three bits of "type", |
| * and the high bit is "size continues". |
| * - each byte afterwards: low seven bits are size continuation, |
| * with the high bit being "size continues" |
| */ |
| static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr) |
| { |
| int n = 1; |
| unsigned char c; |
| |
| if (type < OBJ_COMMIT || type > OBJ_DELTA) |
| die("bad type %d", type); |
| |
| c = (type << 4) | (size & 15); |
| size >>= 4; |
| while (size) { |
| *hdr++ = c | 0x80; |
| c = size & 0x7f; |
| size >>= 7; |
| n++; |
| } |
| *hdr = c; |
| return n; |
| } |
| |
| static unsigned long write_object(struct sha1file *f, struct object_entry *entry) |
| { |
| unsigned long size; |
| char type[10]; |
| void *buf = read_sha1_file(entry->sha1, type, &size); |
| unsigned char header[10]; |
| unsigned hdrlen, datalen; |
| enum object_type obj_type; |
| |
| if (!buf) |
| die("unable to read %s", sha1_to_hex(entry->sha1)); |
| if (size != entry->size) |
| die("object %s size inconsistency (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size); |
| |
| /* |
| * The object header is a byte of 'type' followed by zero or |
| * more bytes of length. For deltas, the 20 bytes of delta sha1 |
| * follows that. |
| */ |
| obj_type = entry->type; |
| if (entry->delta) { |
| buf = delta_against(buf, size, entry); |
| size = entry->delta_size; |
| obj_type = OBJ_DELTA; |
| } |
| hdrlen = encode_header(obj_type, size, header); |
| sha1write(f, header, hdrlen); |
| if (entry->delta) { |
| sha1write(f, entry->delta, 20); |
| hdrlen += 20; |
| } |
| datalen = sha1write_compressed(f, buf, size); |
| free(buf); |
| return hdrlen + datalen; |
| } |
| |
| static unsigned long write_one(struct sha1file *f, |
| struct object_entry *e, |
| unsigned long offset) |
| { |
| if (e->offset) |
| /* offset starts from header size and cannot be zero |
| * if it is written already. |
| */ |
| return offset; |
| e->offset = offset; |
| offset += write_object(f, e); |
| /* if we are delitified, write out its base object. */ |
| if (e->delta) |
| offset = write_one(f, e->delta, offset); |
| return offset; |
| } |
| |
| static void write_pack_file(void) |
| { |
| int i; |
| struct sha1file *f; |
| unsigned long offset; |
| unsigned long mb; |
| struct pack_header hdr; |
| |
| if (!base_name) |
| f = sha1fd(1, "<stdout>"); |
| else |
| f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "pack"); |
| hdr.hdr_signature = htonl(PACK_SIGNATURE); |
| hdr.hdr_version = htonl(PACK_VERSION); |
| hdr.hdr_entries = htonl(nr_objects); |
| sha1write(f, &hdr, sizeof(hdr)); |
| offset = sizeof(hdr); |
| for (i = 0; i < nr_objects; i++) |
| offset = write_one(f, objects + i, offset); |
| |
| sha1close(f, pack_file_sha1, 1); |
| mb = offset >> 20; |
| offset &= 0xfffff; |
| } |
| |
| static void write_index_file(void) |
| { |
| int i; |
| struct sha1file *f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "idx"); |
| struct object_entry **list = sorted_by_sha; |
| struct object_entry **last = list + nr_objects; |
| unsigned int array[256]; |
| |
| /* |
| * 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 object_entry **next = list; |
| while (next < last) { |
| struct object_entry *entry = *next; |
| if (entry->sha1[0] != i) |
| break; |
| next++; |
| } |
| array[i] = htonl(next - sorted_by_sha); |
| list = next; |
| } |
| sha1write(f, array, 256 * sizeof(int)); |
| |
| /* |
| * Write the actual SHA1 entries.. |
| */ |
| list = sorted_by_sha; |
| for (i = 0; i < nr_objects; i++) { |
| struct object_entry *entry = *list++; |
| unsigned int offset = htonl(entry->offset); |
| sha1write(f, &offset, 4); |
| sha1write(f, entry->sha1, 20); |
| } |
| sha1write(f, pack_file_sha1, 20); |
| sha1close(f, NULL, 1); |
| } |
| |
| static int add_object_entry(unsigned char *sha1, unsigned int hash) |
| { |
| unsigned int idx = nr_objects; |
| struct object_entry *entry; |
| |
| if (incremental || local) { |
| struct packed_git *p; |
| |
| for (p = packed_git; p; p = p->next) { |
| struct pack_entry e; |
| |
| if (find_pack_entry_one(sha1, &e, p)) { |
| if (incremental) |
| return 0; |
| if (local && !p->pack_local) |
| return 0; |
| } |
| } |
| } |
| |
| if (idx >= nr_alloc) { |
| unsigned int needed = (idx + 1024) * 3 / 2; |
| objects = xrealloc(objects, needed * sizeof(*entry)); |
| nr_alloc = needed; |
| } |
| entry = objects + idx; |
| memset(entry, 0, sizeof(*entry)); |
| memcpy(entry->sha1, sha1, 20); |
| entry->hash = hash; |
| nr_objects = idx+1; |
| return 1; |
| } |
| |
| static void check_object(struct object_entry *entry) |
| { |
| char type[20]; |
| |
| if (!sha1_object_info(entry->sha1, type, &entry->size)) { |
| if (!strcmp(type, "commit")) { |
| entry->type = OBJ_COMMIT; |
| } else if (!strcmp(type, "tree")) { |
| entry->type = OBJ_TREE; |
| } else if (!strcmp(type, "blob")) { |
| entry->type = OBJ_BLOB; |
| } else if (!strcmp(type, "tag")) { |
| entry->type = OBJ_TAG; |
| } else |
| die("unable to pack object %s of type %s", |
| sha1_to_hex(entry->sha1), type); |
| } |
| else |
| die("unable to get type of object %s", |
| sha1_to_hex(entry->sha1)); |
| } |
| |
| static void get_object_details(void) |
| { |
| int i; |
| struct object_entry *entry = objects; |
| |
| for (i = 0; i < nr_objects; i++) |
| check_object(entry++); |
| } |
| |
| typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *); |
| |
| static entry_sort_t current_sort; |
| |
| static int sort_comparator(const void *_a, const void *_b) |
| { |
| struct object_entry *a = *(struct object_entry **)_a; |
| struct object_entry *b = *(struct object_entry **)_b; |
| return current_sort(a,b); |
| } |
| |
| static struct object_entry **create_sorted_list(entry_sort_t sort) |
| { |
| struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *)); |
| int i; |
| |
| for (i = 0; i < nr_objects; i++) |
| list[i] = objects + i; |
| current_sort = sort; |
| qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator); |
| return list; |
| } |
| |
| static int sha1_sort(const struct object_entry *a, const struct object_entry *b) |
| { |
| return memcmp(a->sha1, b->sha1, 20); |
| } |
| |
| static int type_size_sort(const struct object_entry *a, const struct object_entry *b) |
| { |
| if (a->type < b->type) |
| return -1; |
| if (a->type > b->type) |
| return 1; |
| if (a->hash < b->hash) |
| return -1; |
| if (a->hash > b->hash) |
| return 1; |
| if (a->size < b->size) |
| return -1; |
| if (a->size > b->size) |
| return 1; |
| return a < b ? -1 : (a > b); |
| } |
| |
| struct unpacked { |
| struct object_entry *entry; |
| void *data; |
| }; |
| |
| /* |
| * We search for deltas _backwards_ in a list sorted by type and |
| * by size, so that we see progressively smaller and smaller files. |
| * That's because we prefer deltas to be from the bigger file |
| * to the smaller - deletes are potentially cheaper, but perhaps |
| * more importantly, the bigger file is likely the more recent |
| * one. |
| */ |
| static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_depth) |
| { |
| struct object_entry *cur_entry = cur->entry; |
| struct object_entry *old_entry = old->entry; |
| unsigned long size, oldsize, delta_size, sizediff; |
| long max_size; |
| void *delta_buf; |
| |
| /* Don't bother doing diffs between different types */ |
| if (cur_entry->type != old_entry->type) |
| return -1; |
| |
| size = cur_entry->size; |
| if (size < 50) |
| return -1; |
| oldsize = old_entry->size; |
| sizediff = oldsize > size ? oldsize - size : size - oldsize; |
| if (sizediff > size / 8) |
| return -1; |
| if (old_entry->depth >= max_depth) |
| return 0; |
| |
| /* |
| * NOTE! |
| * |
| * We always delta from the bigger to the smaller, since that's |
| * more space-efficient (deletes don't have to say _what_ they |
| * delete). |
| */ |
| max_size = size / 2 - 20; |
| if (cur_entry->delta) |
| max_size = cur_entry->delta_size-1; |
| if (sizediff >= max_size) |
| return -1; |
| delta_buf = diff_delta(old->data, oldsize, |
| cur->data, size, &delta_size, max_size); |
| if (!delta_buf) |
| return 0; |
| cur_entry->delta = old_entry; |
| cur_entry->delta_size = delta_size; |
| cur_entry->depth = old_entry->depth + 1; |
| free(delta_buf); |
| return 0; |
| } |
| |
| static void find_deltas(struct object_entry **list, int window, int depth) |
| { |
| int i, idx; |
| unsigned int array_size = window * sizeof(struct unpacked); |
| struct unpacked *array = xmalloc(array_size); |
| |
| memset(array, 0, array_size); |
| i = nr_objects; |
| idx = 0; |
| while (--i >= 0) { |
| struct object_entry *entry = list[i]; |
| struct unpacked *n = array + idx; |
| unsigned long size; |
| char type[10]; |
| int j; |
| |
| free(n->data); |
| n->entry = entry; |
| n->data = read_sha1_file(entry->sha1, type, &size); |
| if (size != entry->size) |
| die("object %s inconsistent object length (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size); |
| j = window; |
| while (--j > 0) { |
| unsigned int other_idx = idx + j; |
| struct unpacked *m; |
| if (other_idx >= window) |
| other_idx -= window; |
| m = array + other_idx; |
| if (!m->entry) |
| break; |
| if (try_delta(n, m, depth) < 0) |
| break; |
| } |
| idx++; |
| if (idx >= window) |
| idx = 0; |
| } |
| |
| for (i = 0; i < window; ++i) |
| free(array[i].data); |
| free(array); |
| } |
| |
| static void prepare_pack(int window, int depth) |
| { |
| get_object_details(); |
| |
| fprintf(stderr, "Packing %d objects\n", nr_objects); |
| |
| sorted_by_type = create_sorted_list(type_size_sort); |
| if (window && depth) |
| find_deltas(sorted_by_type, window+1, depth); |
| write_pack_file(); |
| } |
| |
| static int reuse_cached_pack(unsigned char *sha1, int pack_to_stdout) |
| { |
| static const char cache[] = "pack-cache/pack-%s.%s"; |
| char *cached_pack, *cached_idx; |
| int ifd, ofd, ifd_ix = -1; |
| |
| cached_pack = git_path(cache, sha1_to_hex(sha1), "pack"); |
| ifd = open(cached_pack, O_RDONLY); |
| if (ifd < 0) |
| return 0; |
| |
| if (!pack_to_stdout) { |
| cached_idx = git_path(cache, sha1_to_hex(sha1), "idx"); |
| ifd_ix = open(cached_idx, O_RDONLY); |
| if (ifd_ix < 0) { |
| close(ifd); |
| return 0; |
| } |
| } |
| |
| fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects, |
| sha1_to_hex(sha1)); |
| |
| if (pack_to_stdout) { |
| if (copy_fd(ifd, 1)) |
| exit(1); |
| close(ifd); |
| } |
| else { |
| char name[PATH_MAX]; |
| snprintf(name, sizeof(name), |
| "%s-%s.%s", base_name, sha1_to_hex(sha1), "pack"); |
| ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666); |
| if (ofd < 0) |
| die("unable to open %s (%s)", name, strerror(errno)); |
| if (copy_fd(ifd, ofd)) |
| exit(1); |
| close(ifd); |
| |
| snprintf(name, sizeof(name), |
| "%s-%s.%s", base_name, sha1_to_hex(sha1), "idx"); |
| ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666); |
| if (ofd < 0) |
| die("unable to open %s (%s)", name, strerror(errno)); |
| if (copy_fd(ifd_ix, ofd)) |
| exit(1); |
| close(ifd_ix); |
| puts(sha1_to_hex(sha1)); |
| } |
| |
| return 1; |
| } |
| |
| int main(int argc, char **argv) |
| { |
| SHA_CTX ctx; |
| char line[PATH_MAX + 20]; |
| int window = 10, depth = 10, pack_to_stdout = 0; |
| struct object_entry **list; |
| int i; |
| |
| for (i = 1; i < argc; i++) { |
| const char *arg = argv[i]; |
| |
| if (*arg == '-') { |
| if (!strcmp("--non-empty", arg)) { |
| non_empty = 1; |
| continue; |
| } |
| if (!strcmp("--local", arg)) { |
| local = 1; |
| continue; |
| } |
| if (!strcmp("--incremental", arg)) { |
| incremental = 1; |
| continue; |
| } |
| if (!strncmp("--window=", arg, 9)) { |
| char *end; |
| window = strtoul(arg+9, &end, 0); |
| if (!arg[9] || *end) |
| usage(pack_usage); |
| continue; |
| } |
| if (!strncmp("--depth=", arg, 8)) { |
| char *end; |
| depth = strtoul(arg+8, &end, 0); |
| if (!arg[8] || *end) |
| usage(pack_usage); |
| continue; |
| } |
| if (!strcmp("--stdout", arg)) { |
| pack_to_stdout = 1; |
| continue; |
| } |
| usage(pack_usage); |
| } |
| if (base_name) |
| usage(pack_usage); |
| base_name = arg; |
| } |
| |
| if (pack_to_stdout != !base_name) |
| usage(pack_usage); |
| |
| prepare_packed_git(); |
| while (fgets(line, sizeof(line), stdin) != NULL) { |
| unsigned int hash; |
| char *p; |
| unsigned char sha1[20]; |
| |
| if (get_sha1_hex(line, sha1)) |
| die("expected sha1, got garbage:\n %s", line); |
| hash = 0; |
| p = line+40; |
| while (*p) { |
| unsigned char c = *p++; |
| if (isspace(c)) |
| continue; |
| hash = hash * 11 + c; |
| } |
| add_object_entry(sha1, hash); |
| } |
| if (non_empty && !nr_objects) |
| return 0; |
| |
| sorted_by_sha = create_sorted_list(sha1_sort); |
| SHA1_Init(&ctx); |
| list = sorted_by_sha; |
| for (i = 0; i < nr_objects; i++) { |
| struct object_entry *entry = *list++; |
| SHA1_Update(&ctx, entry->sha1, 20); |
| } |
| SHA1_Final(object_list_sha1, &ctx); |
| |
| if (reuse_cached_pack(object_list_sha1, pack_to_stdout)) |
| ; |
| else { |
| prepare_pack(window, depth); |
| if (!pack_to_stdout) { |
| write_index_file(); |
| puts(sha1_to_hex(object_list_sha1)); |
| } |
| } |
| return 0; |
| } |