index-pack.c

   1 #include "cache.h"
   2 #include "delta.h"
   3 #include "pack.h"
   4 #include "csum-file.h"
   5 #include "blob.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "tree.h"
   9 #include "progress.h"
  10 #include "fsck.h"
  11
  12 static const char index_pack_usage[] =
  13 "git index-pack [-v] [-o <index-file>] [{ ---keep | --keep=<msg> }] [--strict] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
  14
  15 struct object_entry
  16 {
  17         struct pack_idx_entry idx;
  18         unsigned long size;
  19         unsigned int hdr_size;
  20         enum object_type type;
  21         enum object_type real_type;
  22 };
  23
  24 union delta_base {
  25         unsigned char sha1[20];
  26         off_t offset;
  27 };
  28
  29 struct base_data {
  30         struct base_data *base;
  31         struct base_data *child;
  32         struct object_entry *obj;
  33         void *data;
  34         unsigned long size;
  35 };
  36
  37 /*
  38  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
  39  * to memcmp() only the first 20 bytes.
  40  */
  41 #define UNION_BASE_SZ   20
  42
  43 #define FLAG_LINK (1u<<20)
  44 #define FLAG_CHECKED (1u<<21)
  45
  46 struct delta_entry
  47 {
  48         union delta_base base;
  49         int obj_no;
  50 };
  51
  52 static struct object_entry *objects;
  53 static struct delta_entry *deltas;
  54 static struct base_data *base_cache;
  55 static size_t base_cache_used;
  56 static int nr_objects;
  57 static int nr_deltas;
  58 static int nr_resolved_deltas;
  59
  60 static int from_stdin;
  61 static int strict;
  62 static int verbose;
  63
  64 static struct progress *progress;
  65
  66 /* We always read in 4kB chunks. */
  67 static unsigned char input_buffer[4096];
  68 static unsigned int input_offset, input_len;
  69 static off_t consumed_bytes;
  70 static git_SHA_CTX input_ctx;
  71 static uint32_t input_crc32;
  72 static int input_fd, output_fd, pack_fd;
  73
  74 static int mark_link(struct object *obj, int type, void *data)
  75 {
  76         if (!obj)
  77                 return -1;
  78
  79         if (type != OBJ_ANY && obj->type != type)
  80                 die("object type mismatch at %s", sha1_to_hex(obj->sha1));
  81
  82         obj->flags |= FLAG_LINK;
  83         return 0;
  84 }
  85
  86 /* The content of each linked object must have been checked
  87    or it must be already present in the object database */
  88 static void check_object(struct object *obj)
  89 {
  90         if (!obj)
  91                 return;
  92
  93         if (!(obj->flags & FLAG_LINK))
  94                 return;
  95
  96         if (!(obj->flags & FLAG_CHECKED)) {
  97                 unsigned long size;
  98                 int type = sha1_object_info(obj->sha1, &size);
  99                 if (type != obj->type || type <= 0)
 100                         die("object of unexpected type");
 101                 obj->flags |= FLAG_CHECKED;
 102                 return;
 103         }
 104 }
 105
 106 static void check_objects(void)
 107 {
 108         unsigned i, max;
 109
 110         max = get_max_object_index();
 111         for (i = 0; i < max; i++)
 112                 check_object(get_indexed_object(i));
 113 }
 114
 115
 116 /* Discard current buffer used content. */
 117 static void flush(void)
 118 {
 119         if (input_offset) {
 120                 if (output_fd >= 0)
 121                         write_or_die(output_fd, input_buffer, input_offset);
 122                 git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 123                 memmove(input_buffer, input_buffer + input_offset, input_len);
 124                 input_offset = 0;
 125         }
 126 }
 127
 128 /*
 129  * Make sure at least "min" bytes are available in the buffer, and
 130  * return the pointer to the buffer.
 131  */
 132 static void *fill(int min)
 133 {
 134         if (min <= input_len)
 135                 return input_buffer + input_offset;
 136         if (min > sizeof(input_buffer))
 137                 die("cannot fill %d bytes", min);
 138         flush();
 139         do {
 140                 ssize_t ret = xread(input_fd, input_buffer + input_len,
 141                                 sizeof(input_buffer) - input_len);
 142                 if (ret <= 0) {
 143                         if (!ret)
 144                                 die("early EOF");
 145                         die("read error on input: %s", strerror(errno));
 146                 }
 147                 input_len += ret;
 148                 if (from_stdin)
 149                         display_throughput(progress, consumed_bytes + input_len);
 150         } while (input_len < min);
 151         return input_buffer;
 152 }
 153
 154 static void use(int bytes)
 155 {
 156         if (bytes > input_len)
 157                 die("used more bytes than were available");
 158         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 159         input_len -= bytes;
 160         input_offset += bytes;
 161
 162         /* make sure off_t is sufficiently large not to wrap */
 163         if (consumed_bytes > consumed_bytes + bytes)
 164                 die("pack too large for current definition of off_t");
 165         consumed_bytes += bytes;
 166 }
 167
 168 static char *open_pack_file(char *pack_name)
 169 {
 170         if (from_stdin) {
 171                 input_fd = 0;
 172                 if (!pack_name) {
 173                         static char tmpfile[PATH_MAX];
 174                         snprintf(tmpfile, sizeof(tmpfile),
 175                                  "%s/pack/tmp_pack_XXXXXX", get_object_directory());
 176                         output_fd = xmkstemp(tmpfile);
 177                         pack_name = xstrdup(tmpfile);
 178                 } else
 179                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 180                 if (output_fd < 0)
 181                         die("unable to create %s: %s\n", pack_name, strerror(errno));
 182                 pack_fd = output_fd;
 183         } else {
 184                 input_fd = open(pack_name, O_RDONLY);
 185                 if (input_fd < 0)
 186                         die("cannot open packfile '%s': %s",
 187                             pack_name, strerror(errno));
 188                 output_fd = -1;
 189                 pack_fd = input_fd;
 190         }
 191         git_SHA1_Init(&input_ctx);
 192         return pack_name;
 193 }
 194
 195 static void parse_pack_header(void)
 196 {
 197         struct pack_header *hdr = fill(sizeof(struct pack_header));
 198
 199         /* Header consistency check */
 200         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 201                 die("pack signature mismatch");
 202         if (!pack_version_ok(hdr->hdr_version))
 203                 die("pack version %"PRIu32" unsupported",
 204                         ntohl(hdr->hdr_version));
 205
 206         nr_objects = ntohl(hdr->hdr_entries);
 207         use(sizeof(struct pack_header));
 208 }
 209
 210 static void bad_object(unsigned long offset, const char *format,
 211                        ...) NORETURN __attribute__((format (printf, 2, 3)));
 212
 213 static void bad_object(unsigned long offset, const char *format, ...)
 214 {
 215         va_list params;
 216         char buf[1024];
 217
 218         va_start(params, format);
 219         vsnprintf(buf, sizeof(buf), format, params);
 220         va_end(params);
 221         die("pack has bad object at offset %lu: %s", offset, buf);
 222 }
 223
 224 static void prune_base_data(struct base_data *retain)
 225 {
 226         struct base_data *b = base_cache;
 227         for (b = base_cache;
 228              base_cache_used > delta_base_cache_limit && b;
 229              b = b->child) {
 230                 if (b->data && b != retain) {
 231                         free(b->data);
 232                         b->data = NULL;
 233                         base_cache_used -= b->size;
 234                 }
 235         }
 236 }
 237
 238 static void link_base_data(struct base_data *base, struct base_data *c)
 239 {
 240         if (base)
 241                 base->child = c;
 242         else
 243                 base_cache = c;
 244
 245         c->base = base;
 246         c->child = NULL;
 247         if (c->data)
 248                 base_cache_used += c->size;
 249         prune_base_data(c);
 250 }
 251
 252 static void unlink_base_data(struct base_data *c)
 253 {
 254         struct base_data *base = c->base;
 255         if (base)
 256                 base->child = NULL;
 257         else
 258                 base_cache = NULL;
 259         if (c->data) {
 260                 free(c->data);
 261                 base_cache_used -= c->size;
 262         }
 263 }
 264
 265 static void *unpack_entry_data(unsigned long offset, unsigned long size)
 266 {
 267         z_stream stream;
 268         void *buf = xmalloc(size);
 269
 270         memset(&stream, 0, sizeof(stream));
 271         stream.next_out = buf;
 272         stream.avail_out = size;
 273         stream.next_in = fill(1);
 274         stream.avail_in = input_len;
 275         inflateInit(&stream);
 276
 277         for (;;) {
 278                 int ret = inflate(&stream, 0);
 279                 use(input_len - stream.avail_in);
 280                 if (stream.total_out == size && ret == Z_STREAM_END)
 281                         break;
 282                 if (ret != Z_OK)
 283                         bad_object(offset, "inflate returned %d", ret);
 284                 stream.next_in = fill(1);
 285                 stream.avail_in = input_len;
 286         }
 287         inflateEnd(&stream);
 288         return buf;
 289 }
 290
 291 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
 292 {
 293         unsigned char *p, c;
 294         unsigned long size;
 295         off_t base_offset;
 296         unsigned shift;
 297         void *data;
 298
 299         obj->idx.offset = consumed_bytes;
 300         input_crc32 = crc32(0, Z_NULL, 0);
 301
 302         p = fill(1);
 303         c = *p;
 304         use(1);
 305         obj->type = (c >> 4) & 7;
 306         size = (c & 15);
 307         shift = 4;
 308         while (c & 0x80) {
 309                 p = fill(1);
 310                 c = *p;
 311                 use(1);
 312                 size += (c & 0x7fUL) << shift;
 313                 shift += 7;
 314         }
 315         obj->size = size;
 316
 317         switch (obj->type) {
 318         case OBJ_REF_DELTA:
 319                 hashcpy(delta_base->sha1, fill(20));
 320                 use(20);
 321                 break;
 322         case OBJ_OFS_DELTA:
 323                 memset(delta_base, 0, sizeof(*delta_base));
 324                 p = fill(1);
 325                 c = *p;
 326                 use(1);
 327                 base_offset = c & 127;
 328                 while (c & 128) {
 329                         base_offset += 1;
 330                         if (!base_offset || MSB(base_offset, 7))
 331                                 bad_object(obj->idx.offset, "offset value overflow for delta base object");
 332                         p = fill(1);
 333                         c = *p;
 334                         use(1);
 335                         base_offset = (base_offset << 7) + (c & 127);
 336                 }
 337                 delta_base->offset = obj->idx.offset - base_offset;
 338                 if (delta_base->offset >= obj->idx.offset)
 339                         bad_object(obj->idx.offset, "delta base offset is out of bound");
 340                 break;
 341         case OBJ_COMMIT:
 342         case OBJ_TREE:
 343         case OBJ_BLOB:
 344         case OBJ_TAG:
 345                 break;
 346         default:
 347                 bad_object(obj->idx.offset, "unknown object type %d", obj->type);
 348         }
 349         obj->hdr_size = consumed_bytes - obj->idx.offset;
 350
 351         data = unpack_entry_data(obj->idx.offset, obj->size);
 352         obj->idx.crc32 = input_crc32;
 353         return data;
 354 }
 355
 356 static void *get_data_from_pack(struct object_entry *obj)
 357 {
 358         off_t from = obj[0].idx.offset + obj[0].hdr_size;
 359         unsigned long len = obj[1].idx.offset - from;
 360         unsigned long rdy = 0;
 361         unsigned char *src, *data;
 362         z_stream stream;
 363         int st;
 364
 365         src = xmalloc(len);
 366         data = src;
 367         do {
 368                 ssize_t n = pread(pack_fd, data + rdy, len - rdy, from + rdy);
 369                 if (n < 0)
 370                         die("cannot pread pack file: %s", strerror(errno));
 371                 if (!n)
 372                         die("premature end of pack file, %lu bytes missing",
 373                             len - rdy);
 374                 rdy += n;
 375         } while (rdy < len);
 376         data = xmalloc(obj->size);
 377         memset(&stream, 0, sizeof(stream));
 378         stream.next_out = data;
 379         stream.avail_out = obj->size;
 380         stream.next_in = src;
 381         stream.avail_in = len;
 382         inflateInit(&stream);
 383         while ((st = inflate(&stream, Z_FINISH)) == Z_OK);
 384         inflateEnd(&stream);
 385         if (st != Z_STREAM_END || stream.total_out != obj->size)
 386                 die("serious inflate inconsistency");
 387         free(src);
 388         return data;
 389 }
 390
 391 static int find_delta(const union delta_base *base)
 392 {
 393         int first = 0, last = nr_deltas;
 394
 395         while (first < last) {
 396                 int next = (first + last) / 2;
 397                 struct delta_entry *delta = &deltas[next];
 398                 int cmp;
 399
 400                 cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
 401                 if (!cmp)
 402                         return next;
 403                 if (cmp < 0) {
 404                         last = next;
 405                         continue;
 406                 }
 407                 first = next+1;
 408         }
 409         return -first-1;
 410 }
 411
 412 static int find_delta_children(const union delta_base *base,
 413                                int *first_index, int *last_index)
 414 {
 415         int first = find_delta(base);
 416         int last = first;
 417         int end = nr_deltas - 1;
 418
 419         if (first < 0)
 420                 return -1;
 421         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
 422                 --first;
 423         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
 424                 ++last;
 425         *first_index = first;
 426         *last_index = last;
 427         return 0;
 428 }
 429
 430 static void sha1_object(const void *data, unsigned long size,
 431                         enum object_type type, unsigned char *sha1)
 432 {
 433         hash_sha1_file(data, size, typename(type), sha1);
 434         if (has_sha1_file(sha1)) {
 435                 void *has_data;
 436                 enum object_type has_type;
 437                 unsigned long has_size;
 438                 has_data = read_sha1_file(sha1, &has_type, &has_size);
 439                 if (!has_data)
 440                         die("cannot read existing object %s", sha1_to_hex(sha1));
 441                 if (size != has_size || type != has_type ||
 442                     memcmp(data, has_data, size) != 0)
 443                         die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
 444                 free(has_data);
 445         }
 446         if (strict) {
 447                 if (type == OBJ_BLOB) {
 448                         struct blob *blob = lookup_blob(sha1);
 449                         if (blob)
 450                                 blob->object.flags |= FLAG_CHECKED;
 451                         else
 452                                 die("invalid blob object %s", sha1_to_hex(sha1));
 453                 } else {
 454                         struct object *obj;
 455                         int eaten;
 456                         void *buf = (void *) data;
 457
 458                         /*
 459                          * we do not need to free the memory here, as the
 460                          * buf is deleted by the caller.
 461                          */
 462                         obj = parse_object_buffer(sha1, type, size, buf, &eaten);
 463                         if (!obj)
 464                                 die("invalid %s", typename(type));
 465                         if (fsck_object(obj, 1, fsck_error_function))
 466                                 die("Error in object");
 467                         if (fsck_walk(obj, mark_link, 0))
 468                                 die("Not all child objects of %s are reachable", sha1_to_hex(obj->sha1));
 469
 470                         if (obj->type == OBJ_TREE) {
 471                                 struct tree *item = (struct tree *) obj;
 472                                 item->buffer = NULL;
 473                         }
 474                         if (obj->type == OBJ_COMMIT) {
 475                                 struct commit *commit = (struct commit *) obj;
 476                                 commit->buffer = NULL;
 477                         }
 478                         obj->flags |= FLAG_CHECKED;
 479                 }
 480         }
 481 }
 482
 483 static void *get_base_data(struct base_data *c)
 484 {
 485         if (!c->data) {
 486                 struct object_entry *obj = c->obj;
 487
 488                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 489                         void *base = get_base_data(c->base);
 490                         void *raw = get_data_from_pack(obj);
 491                         c->data = patch_delta(
 492                                 base, c->base->size,
 493                                 raw, obj->size,
 494                                 &c->size);
 495                         free(raw);
 496                         if (!c->data)
 497                                 bad_object(obj->idx.offset, "failed to apply delta");
 498                 } else {
 499                         c->data = get_data_from_pack(obj);
 500                         c->size = obj->size;
 501                 }
 502
 503                 base_cache_used += c->size;
 504                 prune_base_data(c);
 505         }
 506         return c->data;
 507 }
 508
 509 static void resolve_delta(struct object_entry *delta_obj,
 510                           struct base_data *base, struct base_data *result)
 511 {
 512         void *delta_data;
 513         unsigned long delta_size;
 514
 515         delta_obj->real_type = base->obj->type;
 516         delta_data = get_data_from_pack(delta_obj);
 517         delta_size = delta_obj->size;
 518         result->obj = delta_obj;
 519         result->data = patch_delta(get_base_data(base), base->obj->size,
 520                                    delta_data, delta_size, &result->size);
 521         free(delta_data);
 522         if (!result->data)
 523                 bad_object(delta_obj->idx.offset, "failed to apply delta");
 524         sha1_object(result->data, result->size, delta_obj->real_type,
 525                     delta_obj->idx.sha1);
 526         nr_resolved_deltas++;
 527 }
 528
 529 static void find_unresolved_deltas(struct base_data *base,
 530                                    struct base_data *prev_base)
 531 {
 532         int i, ref, ref_first, ref_last, ofs, ofs_first, ofs_last;
 533
 534         /*
 535          * This is a recursive function. Those brackets should help reducing
 536          * stack usage by limiting the scope of the delta_base union.
 537          */
 538         {
 539                 union delta_base base_spec;
 540
 541                 hashcpy(base_spec.sha1, base->obj->idx.sha1);
 542                 ref = !find_delta_children(&base_spec, &ref_first, &ref_last);
 543
 544                 memset(&base_spec, 0, sizeof(base_spec));
 545                 base_spec.offset = base->obj->idx.offset;
 546                 ofs = !find_delta_children(&base_spec, &ofs_first, &ofs_last);
 547         }
 548
 549         if (!ref && !ofs)
 550                 return;
 551
 552         link_base_data(prev_base, base);
 553
 554         if (ref) {
 555                 for (i = ref_first; i <= ref_last; i++) {
 556                         struct object_entry *child = objects + deltas[i].obj_no;
 557                         if (child->real_type == OBJ_REF_DELTA) {
 558                                 struct base_data result;
 559                                 resolve_delta(child, base, &result);
 560                                 find_unresolved_deltas(&result, base);
 561                         }
 562                 }
 563         }
 564
 565         if (ofs) {
 566                 for (i = ofs_first; i <= ofs_last; i++) {
 567                         struct object_entry *child = objects + deltas[i].obj_no;
 568                         if (child->real_type == OBJ_OFS_DELTA) {
 569                                 struct base_data result;
 570                                 resolve_delta(child, base, &result);
 571                                 find_unresolved_deltas(&result, base);
 572                         }
 573                 }
 574         }
 575
 576         unlink_base_data(base);
 577 }
 578
 579 static int compare_delta_entry(const void *a, const void *b)
 580 {
 581         const struct delta_entry *delta_a = a;
 582         const struct delta_entry *delta_b = b;
 583         return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
 584 }
 585
 586 /* Parse all objects and return the pack content SHA1 hash */
 587 static void parse_pack_objects(unsigned char *sha1)
 588 {
 589         int i;
 590         struct delta_entry *delta = deltas;
 591         struct stat st;
 592
 593         /*
 594          * First pass:
 595          * - find locations of all objects;
 596          * - calculate SHA1 of all non-delta objects;
 597          * - remember base (SHA1 or offset) for all deltas.
 598          */
 599         if (verbose)
 600                 progress = start_progress(
 601                                 from_stdin ? "Receiving objects" : "Indexing objects",
 602                                 nr_objects);
 603         for (i = 0; i < nr_objects; i++) {
 604                 struct object_entry *obj = &objects[i];
 605                 void *data = unpack_raw_entry(obj, &delta->base);
 606                 obj->real_type = obj->type;
 607                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 608                         nr_deltas++;
 609                         delta->obj_no = i;
 610                         delta++;
 611                 } else
 612                         sha1_object(data, obj->size, obj->type, obj->idx.sha1);
 613                 free(data);
 614                 display_progress(progress, i+1);
 615         }
 616         objects[i].idx.offset = consumed_bytes;
 617         stop_progress(&progress);
 618
 619         /* Check pack integrity */
 620         flush();
 621         git_SHA1_Final(sha1, &input_ctx);
 622         if (hashcmp(fill(20), sha1))
 623                 die("pack is corrupted (SHA1 mismatch)");
 624         use(20);
 625
 626         /* If input_fd is a file, we should have reached its end now. */
 627         if (fstat(input_fd, &st))
 628                 die("cannot fstat packfile: %s", strerror(errno));
 629         if (S_ISREG(st.st_mode) &&
 630                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
 631                 die("pack has junk at the end");
 632
 633         if (!nr_deltas)
 634                 return;
 635
 636         /* Sort deltas by base SHA1/offset for fast searching */
 637         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
 638               compare_delta_entry);
 639
 640         /*
 641          * Second pass:
 642          * - for all non-delta objects, look if it is used as a base for
 643          *   deltas;
 644          * - if used as a base, uncompress the object and apply all deltas,
 645          *   recursively checking if the resulting object is used as a base
 646          *   for some more deltas.
 647          */
 648         if (verbose)
 649                 progress = start_progress("Resolving deltas", nr_deltas);
 650         for (i = 0; i < nr_objects; i++) {
 651                 struct object_entry *obj = &objects[i];
 652                 struct base_data base_obj;
 653
 654                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
 655                         continue;
 656                 base_obj.obj = obj;
 657                 base_obj.data = NULL;
 658                 find_unresolved_deltas(&base_obj, NULL);
 659                 display_progress(progress, nr_resolved_deltas);
 660         }
 661 }
 662
 663 static int write_compressed(struct sha1file *f, void *in, unsigned int size)
 664 {
 665         z_stream stream;
 666         unsigned long maxsize;
 667         void *out;
 668
 669         memset(&stream, 0, sizeof(stream));
 670         deflateInit(&stream, zlib_compression_level);
 671         maxsize = deflateBound(&stream, size);
 672         out = xmalloc(maxsize);
 673
 674         /* Compress it */
 675         stream.next_in = in;
 676         stream.avail_in = size;
 677         stream.next_out = out;
 678         stream.avail_out = maxsize;
 679         while (deflate(&stream, Z_FINISH) == Z_OK);
 680         deflateEnd(&stream);
 681
 682         size = stream.total_out;
 683         sha1write(f, out, size);
 684         free(out);
 685         return size;
 686 }
 687
 688 static struct object_entry *append_obj_to_pack(struct sha1file *f,
 689                                const unsigned char *sha1, void *buf,
 690                                unsigned long size, enum object_type type)
 691 {
 692         struct object_entry *obj = &objects[nr_objects++];
 693         unsigned char header[10];
 694         unsigned long s = size;
 695         int n = 0;
 696         unsigned char c = (type << 4) | (s & 15);
 697         s >>= 4;
 698         while (s) {
 699                 header[n++] = c | 0x80;
 700                 c = s & 0x7f;
 701                 s >>= 7;
 702         }
 703         header[n++] = c;
 704         crc32_begin(f);
 705         sha1write(f, header, n);
 706         obj[0].size = size;
 707         obj[0].hdr_size = n;
 708         obj[0].type = type;
 709         obj[0].real_type = type;
 710         obj[1].idx.offset = obj[0].idx.offset + n;
 711         obj[1].idx.offset += write_compressed(f, buf, size);
 712         obj[0].idx.crc32 = crc32_end(f);
 713         sha1flush(f);
 714         hashcpy(obj->idx.sha1, sha1);
 715         return obj;
 716 }
 717
 718 static int delta_pos_compare(const void *_a, const void *_b)
 719 {
 720         struct delta_entry *a = *(struct delta_entry **)_a;
 721         struct delta_entry *b = *(struct delta_entry **)_b;
 722         return a->obj_no - b->obj_no;
 723 }
 724
 725 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
 726 {
 727         struct delta_entry **sorted_by_pos;
 728         int i, n = 0;
 729
 730         /*
 731          * Since many unresolved deltas may well be themselves base objects
 732          * for more unresolved deltas, we really want to include the
 733          * smallest number of base objects that would cover as much delta
 734          * as possible by picking the
 735          * trunc deltas first, allowing for other deltas to resolve without
 736          * additional base objects.  Since most base objects are to be found
 737          * before deltas depending on them, a good heuristic is to start
 738          * resolving deltas in the same order as their position in the pack.
 739          */
 740         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
 741         for (i = 0; i < nr_deltas; i++) {
 742                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
 743                         continue;
 744                 sorted_by_pos[n++] = &deltas[i];
 745         }
 746         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
 747
 748         for (i = 0; i < n; i++) {
 749                 struct delta_entry *d = sorted_by_pos[i];
 750                 enum object_type type;
 751                 struct base_data base_obj;
 752
 753                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
 754                         continue;
 755                 base_obj.data = read_sha1_file(d->base.sha1, &type, &base_obj.size);
 756                 if (!base_obj.data)
 757                         continue;
 758
 759                 if (check_sha1_signature(d->base.sha1, base_obj.data,
 760                                 base_obj.size, typename(type)))
 761                         die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
 762                 base_obj.obj = append_obj_to_pack(f, d->base.sha1,
 763                                         base_obj.data, base_obj.size, type);
 764                 find_unresolved_deltas(&base_obj, NULL);
 765                 display_progress(progress, nr_resolved_deltas);
 766         }
 767         free(sorted_by_pos);
 768 }
 769
 770 static void final(const char *final_pack_name, const char *curr_pack_name,
 771                   const char *final_index_name, const char *curr_index_name,
 772                   const char *keep_name, const char *keep_msg,
 773                   unsigned char *sha1)
 774 {
 775         const char *report = "pack";
 776         char name[PATH_MAX];
 777         int err;
 778
 779         if (!from_stdin) {
 780                 close(input_fd);
 781         } else {
 782                 fsync_or_die(output_fd, curr_pack_name);
 783                 err = close(output_fd);
 784                 if (err)
 785                         die("error while closing pack file: %s", strerror(errno));
 786                 chmod(curr_pack_name, 0444);
 787         }
 788
 789         if (keep_msg) {
 790                 int keep_fd, keep_msg_len = strlen(keep_msg);
 791                 if (!keep_name) {
 792                         snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
 793                                  get_object_directory(), sha1_to_hex(sha1));
 794                         keep_name = name;
 795                 }
 796                 keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
 797                 if (keep_fd < 0) {
 798                         if (errno != EEXIST)
 799                                 die("cannot write keep file");
 800                 } else {
 801                         if (keep_msg_len > 0) {
 802                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
 803                                 write_or_die(keep_fd, "\n", 1);
 804                         }
 805                         if (close(keep_fd) != 0)
 806                                 die("cannot write keep file");
 807                         report = "keep";
 808                 }
 809         }
 810
 811         if (final_pack_name != curr_pack_name) {
 812                 if (!final_pack_name) {
 813                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
 814                                  get_object_directory(), sha1_to_hex(sha1));
 815                         final_pack_name = name;
 816                 }
 817                 if (move_temp_to_file(curr_pack_name, final_pack_name))
 818                         die("cannot store pack file");
 819         }
 820
 821         chmod(curr_index_name, 0444);
 822         if (final_index_name != curr_index_name) {
 823                 if (!final_index_name) {
 824                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
 825                                  get_object_directory(), sha1_to_hex(sha1));
 826                         final_index_name = name;
 827                 }
 828                 if (move_temp_to_file(curr_index_name, final_index_name))
 829                         die("cannot store index file");
 830         }
 831
 832         if (!from_stdin) {
 833                 printf("%s\n", sha1_to_hex(sha1));
 834         } else {
 835                 char buf[48];
 836                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
 837                                    report, sha1_to_hex(sha1));
 838                 write_or_die(1, buf, len);
 839
 840                 /*
 841                  * Let's just mimic git-unpack-objects here and write
 842                  * the last part of the input buffer to stdout.
 843                  */
 844                 while (input_len) {
 845                         err = xwrite(1, input_buffer + input_offset, input_len);
 846                         if (err <= 0)
 847                                 break;
 848                         input_len -= err;
 849                         input_offset += err;
 850                 }
 851         }
 852 }
 853
 854 static int git_index_pack_config(const char *k, const char *v, void *cb)
 855 {
 856         if (!strcmp(k, "pack.indexversion")) {
 857                 pack_idx_default_version = git_config_int(k, v);
 858                 if (pack_idx_default_version > 2)
 859                         die("bad pack.indexversion=%"PRIu32,
 860                                 pack_idx_default_version);
 861                 return 0;
 862         }
 863         return git_default_config(k, v, cb);
 864 }
 865
 866 int main(int argc, char **argv)
 867 {
 868         int i, fix_thin_pack = 0;
 869         char *curr_pack, *pack_name = NULL;
 870         char *curr_index, *index_name = NULL;
 871         const char *keep_name = NULL, *keep_msg = NULL;
 872         char *index_name_buf = NULL, *keep_name_buf = NULL;
 873         struct pack_idx_entry **idx_objects;
 874         unsigned char pack_sha1[20];
 875         int nongit = 0;
 876
 877         setup_git_directory_gently(&nongit);
 878         git_config(git_index_pack_config, NULL);
 879
 880         for (i = 1; i < argc; i++) {
 881                 char *arg = argv[i];
 882
 883                 if (*arg == '-') {
 884                         if (!strcmp(arg, "--stdin")) {
 885                                 from_stdin = 1;
 886                         } else if (!strcmp(arg, "--fix-thin")) {
 887                                 fix_thin_pack = 1;
 888                         } else if (!strcmp(arg, "--strict")) {
 889                                 strict = 1;
 890                         } else if (!strcmp(arg, "--keep")) {
 891                                 keep_msg = "";
 892                         } else if (!prefixcmp(arg, "--keep=")) {
 893                                 keep_msg = arg + 7;
 894                         } else if (!prefixcmp(arg, "--pack_header=")) {
 895                                 struct pack_header *hdr;
 896                                 char *c;
 897
 898                                 hdr = (struct pack_header *)input_buffer;
 899                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
 900                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
 901                                 if (*c != ',')
 902                                         die("bad %s", arg);
 903                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
 904                                 if (*c)
 905                                         die("bad %s", arg);
 906                                 input_len = sizeof(*hdr);
 907                         } else if (!strcmp(arg, "-v")) {
 908                                 verbose = 1;
 909                         } else if (!strcmp(arg, "-o")) {
 910                                 if (index_name || (i+1) >= argc)
 911                                         usage(index_pack_usage);
 912                                 index_name = argv[++i];
 913                         } else if (!prefixcmp(arg, "--index-version=")) {
 914                                 char *c;
 915                                 pack_idx_default_version = strtoul(arg + 16, &c, 10);
 916                                 if (pack_idx_default_version > 2)
 917                                         die("bad %s", arg);
 918                                 if (*c == ',')
 919                                         pack_idx_off32_limit = strtoul(c+1, &c, 0);
 920                                 if (*c || pack_idx_off32_limit & 0x80000000)
 921                                         die("bad %s", arg);
 922                         } else
 923                                 usage(index_pack_usage);
 924                         continue;
 925                 }
 926
 927                 if (pack_name)
 928                         usage(index_pack_usage);
 929                 pack_name = arg;
 930         }
 931
 932         if (!pack_name && !from_stdin)
 933                 usage(index_pack_usage);
 934         if (fix_thin_pack && !from_stdin)
 935                 die("--fix-thin cannot be used without --stdin");
 936         if (!index_name && pack_name) {
 937                 int len = strlen(pack_name);
 938                 if (!has_extension(pack_name, ".pack"))
 939                         die("packfile name '%s' does not end with '.pack'",
 940                             pack_name);
 941                 index_name_buf = xmalloc(len);
 942                 memcpy(index_name_buf, pack_name, len - 5);
 943                 strcpy(index_name_buf + len - 5, ".idx");
 944                 index_name = index_name_buf;
 945         }
 946         if (keep_msg && !keep_name && pack_name) {
 947                 int len = strlen(pack_name);
 948                 if (!has_extension(pack_name, ".pack"))
 949                         die("packfile name '%s' does not end with '.pack'",
 950                             pack_name);
 951                 keep_name_buf = xmalloc(len);
 952                 memcpy(keep_name_buf, pack_name, len - 5);
 953                 strcpy(keep_name_buf + len - 5, ".keep");
 954                 keep_name = keep_name_buf;
 955         }
 956
 957         curr_pack = open_pack_file(pack_name);
 958         parse_pack_header();
 959         objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
 960         deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
 961         parse_pack_objects(pack_sha1);
 962         if (nr_deltas == nr_resolved_deltas) {
 963                 stop_progress(&progress);
 964                 /* Flush remaining pack final 20-byte SHA1. */
 965                 flush();
 966         } else {
 967                 if (fix_thin_pack) {
 968                         struct sha1file *f;
 969                         unsigned char read_sha1[20], tail_sha1[20];
 970                         char msg[48];
 971                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
 972                         int nr_objects_initial = nr_objects;
 973                         if (nr_unresolved <= 0)
 974                                 die("confusion beyond insanity");
 975                         objects = xrealloc(objects,
 976                                            (nr_objects + nr_unresolved + 1)
 977                                            * sizeof(*objects));
 978                         f = sha1fd(output_fd, curr_pack);
 979                         fix_unresolved_deltas(f, nr_unresolved);
 980                         sprintf(msg, "completed with %d local objects",
 981                                 nr_objects - nr_objects_initial);
 982                         stop_progress_msg(&progress, msg);
 983                         sha1close(f, tail_sha1, 0);
 984                         hashcpy(read_sha1, pack_sha1);
 985                         fixup_pack_header_footer(output_fd, pack_sha1,
 986                                                  curr_pack, nr_objects,
 987                                                  read_sha1, consumed_bytes-20);
 988                         if (hashcmp(read_sha1, tail_sha1) != 0)
 989                                 die("Unexpected tail checksum for %s "
 990                                     "(disk corruption?)", curr_pack);
 991                 }
 992                 if (nr_deltas != nr_resolved_deltas)
 993                         die("pack has %d unresolved deltas",
 994                             nr_deltas - nr_resolved_deltas);
 995         }
 996         free(deltas);
 997         if (strict)
 998                 check_objects();
 999
1000         idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
1001         for (i = 0; i < nr_objects; i++)
1002                 idx_objects[i] = &objects[i].idx;
1003         curr_index = write_idx_file(index_name, idx_objects, nr_objects, pack_sha1);
1004         free(idx_objects);
1005
1006         final(pack_name, curr_pack,
1007                 index_name, curr_index,
1008                 keep_name, keep_msg,
1009                 pack_sha1);
1010         free(objects);
1011         free(index_name_buf);
1012         free(keep_name_buf);
1013         if (pack_name == NULL)
1014                 free(curr_pack);
1015         if (index_name == NULL)
1016                 free(curr_index);
1017
1018         return 0;
1019 }