builtin/index-pack.c

   1 #include "builtin.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 #include "exec_cmd.h"
  12 #include "thread-utils.h"
  13
  14 static const char index_pack_usage[] =
  15 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
  16
  17 struct object_entry {
  18         struct pack_idx_entry idx;
  19         unsigned long size;
  20         unsigned int hdr_size;
  21         enum object_type type;
  22         enum object_type real_type;
  23         unsigned delta_depth;
  24         int base_object_no;
  25 };
  26
  27 union delta_base {
  28         unsigned char sha1[20];
  29         off_t offset;
  30 };
  31
  32 struct base_data {
  33         struct base_data *base;
  34         struct base_data *child;
  35         struct object_entry *obj;
  36         void *data;
  37         unsigned long size;
  38         int ref_first, ref_last;
  39         int ofs_first, ofs_last;
  40 };
  41
  42 #if !defined(NO_PTHREADS) && defined(NO_PREAD)
  43 /* NO_PREAD uses compat/pread.c, which is not thread-safe. Disable threading. */
  44 #define NO_PTHREADS
  45 #endif
  46
  47 struct thread_local {
  48 #ifndef NO_PTHREADS
  49         pthread_t thread;
  50 #endif
  51         struct base_data *base_cache;
  52         size_t base_cache_used;
  53 };
  54
  55 /*
  56  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
  57  * to memcmp() only the first 20 bytes.
  58  */
  59 #define UNION_BASE_SZ   20
  60
  61 #define FLAG_LINK (1u<<20)
  62 #define FLAG_CHECKED (1u<<21)
  63
  64 struct delta_entry {
  65         union delta_base base;
  66         int obj_no;
  67 };
  68
  69 static struct object_entry *objects;
  70 static struct delta_entry *deltas;
  71 static struct thread_local nothread_data;
  72 static int nr_objects;
  73 static int nr_deltas;
  74 static int nr_resolved_deltas;
  75 static int nr_threads;
  76
  77 static int from_stdin;
  78 static int strict;
  79 static int verbose;
  80
  81 static struct progress *progress;
  82
  83 /* We always read in 4kB chunks. */
  84 static unsigned char input_buffer[4096];
  85 static unsigned int input_offset, input_len;
  86 static off_t consumed_bytes;
  87 static unsigned deepest_delta;
  88 static git_SHA_CTX input_ctx;
  89 static uint32_t input_crc32;
  90 static int input_fd, output_fd, pack_fd;
  91
  92 #ifndef NO_PTHREADS
  93
  94 static struct thread_local *thread_data;
  95 static int nr_dispatched;
  96 static int threads_active;
  97
  98 static pthread_mutex_t read_mutex;
  99 #define read_lock()             lock_mutex(&read_mutex)
 100 #define read_unlock()           unlock_mutex(&read_mutex)
 101
 102 static pthread_mutex_t counter_mutex;
 103 #define counter_lock()          lock_mutex(&counter_mutex)
 104 #define counter_unlock()        unlock_mutex(&counter_mutex)
 105
 106 static pthread_mutex_t work_mutex;
 107 #define work_lock()             lock_mutex(&work_mutex)
 108 #define work_unlock()           unlock_mutex(&work_mutex)
 109
 110 static pthread_key_t key;
 111
 112 static inline void lock_mutex(pthread_mutex_t *mutex)
 113 {
 114         if (threads_active)
 115                 pthread_mutex_lock(mutex);
 116 }
 117
 118 static inline void unlock_mutex(pthread_mutex_t *mutex)
 119 {
 120         if (threads_active)
 121                 pthread_mutex_unlock(mutex);
 122 }
 123
 124 /*
 125  * Mutex and conditional variable can't be statically-initialized on Windows.
 126  */
 127 static void init_thread(void)
 128 {
 129         init_recursive_mutex(&read_mutex);
 130         pthread_mutex_init(&counter_mutex, NULL);
 131         pthread_mutex_init(&work_mutex, NULL);
 132         pthread_key_create(&key, NULL);
 133         thread_data = xcalloc(nr_threads, sizeof(*thread_data));
 134         threads_active = 1;
 135 }
 136
 137 static void cleanup_thread(void)
 138 {
 139         if (!threads_active)
 140                 return;
 141         threads_active = 0;
 142         pthread_mutex_destroy(&read_mutex);
 143         pthread_mutex_destroy(&counter_mutex);
 144         pthread_mutex_destroy(&work_mutex);
 145         pthread_key_delete(key);
 146         free(thread_data);
 147 }
 148
 149 #else
 150
 151 #define read_lock()
 152 #define read_unlock()
 153
 154 #define counter_lock()
 155 #define counter_unlock()
 156
 157 #define work_lock()
 158 #define work_unlock()
 159
 160 #endif
 161
 162
 163 static int mark_link(struct object *obj, int type, void *data)
 164 {
 165         if (!obj)
 166                 return -1;
 167
 168         if (type != OBJ_ANY && obj->type != type)
 169                 die(_("object type mismatch at %s"), sha1_to_hex(obj->sha1));
 170
 171         obj->flags |= FLAG_LINK;
 172         return 0;
 173 }
 174
 175 /* The content of each linked object must have been checked
 176    or it must be already present in the object database */
 177 static void check_object(struct object *obj)
 178 {
 179         if (!obj)
 180                 return;
 181
 182         if (!(obj->flags & FLAG_LINK))
 183                 return;
 184
 185         if (!(obj->flags & FLAG_CHECKED)) {
 186                 unsigned long size;
 187                 int type = sha1_object_info(obj->sha1, &size);
 188                 if (type != obj->type || type <= 0)
 189                         die(_("object of unexpected type"));
 190                 obj->flags |= FLAG_CHECKED;
 191                 return;
 192         }
 193 }
 194
 195 static void check_objects(void)
 196 {
 197         unsigned i, max;
 198
 199         max = get_max_object_index();
 200         for (i = 0; i < max; i++)
 201                 check_object(get_indexed_object(i));
 202 }
 203
 204
 205 /* Discard current buffer used content. */
 206 static void flush(void)
 207 {
 208         if (input_offset) {
 209                 if (output_fd >= 0)
 210                         write_or_die(output_fd, input_buffer, input_offset);
 211                 git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 212                 memmove(input_buffer, input_buffer + input_offset, input_len);
 213                 input_offset = 0;
 214         }
 215 }
 216
 217 /*
 218  * Make sure at least "min" bytes are available in the buffer, and
 219  * return the pointer to the buffer.
 220  */
 221 static void *fill(int min)
 222 {
 223         if (min <= input_len)
 224                 return input_buffer + input_offset;
 225         if (min > sizeof(input_buffer))
 226                 die(Q_("cannot fill %d byte",
 227                        "cannot fill %d bytes",
 228                        min),
 229                     min);
 230         flush();
 231         do {
 232                 ssize_t ret = xread(input_fd, input_buffer + input_len,
 233                                 sizeof(input_buffer) - input_len);
 234                 if (ret <= 0) {
 235                         if (!ret)
 236                                 die(_("early EOF"));
 237                         die_errno(_("read error on input"));
 238                 }
 239                 input_len += ret;
 240                 if (from_stdin)
 241                         display_throughput(progress, consumed_bytes + input_len);
 242         } while (input_len < min);
 243         return input_buffer;
 244 }
 245
 246 static void use(int bytes)
 247 {
 248         if (bytes > input_len)
 249                 die(_("used more bytes than were available"));
 250         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 251         input_len -= bytes;
 252         input_offset += bytes;
 253
 254         /* make sure off_t is sufficiently large not to wrap */
 255         if (signed_add_overflows(consumed_bytes, bytes))
 256                 die(_("pack too large for current definition of off_t"));
 257         consumed_bytes += bytes;
 258 }
 259
 260 static const char *open_pack_file(const char *pack_name)
 261 {
 262         if (from_stdin) {
 263                 input_fd = 0;
 264                 if (!pack_name) {
 265                         static char tmp_file[PATH_MAX];
 266                         output_fd = odb_mkstemp(tmp_file, sizeof(tmp_file),
 267                                                 "pack/tmp_pack_XXXXXX");
 268                         pack_name = xstrdup(tmp_file);
 269                 } else
 270                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 271                 if (output_fd < 0)
 272                         die_errno(_("unable to create '%s'"), pack_name);
 273                 pack_fd = output_fd;
 274         } else {
 275                 input_fd = open(pack_name, O_RDONLY);
 276                 if (input_fd < 0)
 277                         die_errno(_("cannot open packfile '%s'"), pack_name);
 278                 output_fd = -1;
 279                 pack_fd = input_fd;
 280         }
 281         git_SHA1_Init(&input_ctx);
 282         return pack_name;
 283 }
 284
 285 static void parse_pack_header(void)
 286 {
 287         struct pack_header *hdr = fill(sizeof(struct pack_header));
 288
 289         /* Header consistency check */
 290         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 291                 die(_("pack signature mismatch"));
 292         if (!pack_version_ok(hdr->hdr_version))
 293                 die("pack version %"PRIu32" unsupported",
 294                         ntohl(hdr->hdr_version));
 295
 296         nr_objects = ntohl(hdr->hdr_entries);
 297         use(sizeof(struct pack_header));
 298 }
 299
 300 static NORETURN void bad_object(unsigned long offset, const char *format,
 301                        ...) __attribute__((format (printf, 2, 3)));
 302
 303 static NORETURN void bad_object(unsigned long offset, const char *format, ...)
 304 {
 305         va_list params;
 306         char buf[1024];
 307
 308         va_start(params, format);
 309         vsnprintf(buf, sizeof(buf), format, params);
 310         va_end(params);
 311         die(_("pack has bad object at offset %lu: %s"), offset, buf);
 312 }
 313
 314 static inline struct thread_local *get_thread_data(void)
 315 {
 316 #ifndef NO_PTHREADS
 317         if (threads_active)
 318                 return pthread_getspecific(key);
 319         assert(!threads_active &&
 320                "This should only be reached when all threads are gone");
 321 #endif
 322         return &nothread_data;
 323 }
 324
 325 #ifndef NO_PTHREADS
 326 static void set_thread_data(struct thread_local *data)
 327 {
 328         if (threads_active)
 329                 pthread_setspecific(key, data);
 330 }
 331 #endif
 332
 333 static struct base_data *alloc_base_data(void)
 334 {
 335         struct base_data *base = xmalloc(sizeof(struct base_data));
 336         memset(base, 0, sizeof(*base));
 337         base->ref_last = -1;
 338         base->ofs_last = -1;
 339         return base;
 340 }
 341
 342 static void free_base_data(struct base_data *c)
 343 {
 344         if (c->data) {
 345                 free(c->data);
 346                 c->data = NULL;
 347                 get_thread_data()->base_cache_used -= c->size;
 348         }
 349 }
 350
 351 static void prune_base_data(struct base_data *retain)
 352 {
 353         struct base_data *b;
 354         struct thread_local *data = get_thread_data();
 355         for (b = data->base_cache;
 356              data->base_cache_used > delta_base_cache_limit && b;
 357              b = b->child) {
 358                 if (b->data && b != retain)
 359                         free_base_data(b);
 360         }
 361 }
 362
 363 static void link_base_data(struct base_data *base, struct base_data *c)
 364 {
 365         if (base)
 366                 base->child = c;
 367         else
 368                 get_thread_data()->base_cache = c;
 369
 370         c->base = base;
 371         c->child = NULL;
 372         if (c->data)
 373                 get_thread_data()->base_cache_used += c->size;
 374         prune_base_data(c);
 375 }
 376
 377 static void unlink_base_data(struct base_data *c)
 378 {
 379         struct base_data *base = c->base;
 380         if (base)
 381                 base->child = NULL;
 382         else
 383                 get_thread_data()->base_cache = NULL;
 384         free_base_data(c);
 385 }
 386
 387 static void *unpack_entry_data(unsigned long offset, unsigned long size)
 388 {
 389         int status;
 390         git_zstream stream;
 391         void *buf = xmalloc(size);
 392
 393         memset(&stream, 0, sizeof(stream));
 394         git_inflate_init(&stream);
 395         stream.next_out = buf;
 396         stream.avail_out = size;
 397
 398         do {
 399                 stream.next_in = fill(1);
 400                 stream.avail_in = input_len;
 401                 status = git_inflate(&stream, 0);
 402                 use(input_len - stream.avail_in);
 403         } while (status == Z_OK);
 404         if (stream.total_out != size || status != Z_STREAM_END)
 405                 bad_object(offset, _("inflate returned %d"), status);
 406         git_inflate_end(&stream);
 407         return buf;
 408 }
 409
 410 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
 411 {
 412         unsigned char *p;
 413         unsigned long size, c;
 414         off_t base_offset;
 415         unsigned shift;
 416         void *data;
 417
 418         obj->idx.offset = consumed_bytes;
 419         input_crc32 = crc32(0, NULL, 0);
 420
 421         p = fill(1);
 422         c = *p;
 423         use(1);
 424         obj->type = (c >> 4) & 7;
 425         size = (c & 15);
 426         shift = 4;
 427         while (c & 0x80) {
 428                 p = fill(1);
 429                 c = *p;
 430                 use(1);
 431                 size += (c & 0x7f) << shift;
 432                 shift += 7;
 433         }
 434         obj->size = size;
 435
 436         switch (obj->type) {
 437         case OBJ_REF_DELTA:
 438                 hashcpy(delta_base->sha1, fill(20));
 439                 use(20);
 440                 break;
 441         case OBJ_OFS_DELTA:
 442                 memset(delta_base, 0, sizeof(*delta_base));
 443                 p = fill(1);
 444                 c = *p;
 445                 use(1);
 446                 base_offset = c & 127;
 447                 while (c & 128) {
 448                         base_offset += 1;
 449                         if (!base_offset || MSB(base_offset, 7))
 450                                 bad_object(obj->idx.offset, _("offset value overflow for delta base object"));
 451                         p = fill(1);
 452                         c = *p;
 453                         use(1);
 454                         base_offset = (base_offset << 7) + (c & 127);
 455                 }
 456                 delta_base->offset = obj->idx.offset - base_offset;
 457                 if (delta_base->offset <= 0 || delta_base->offset >= obj->idx.offset)
 458                         bad_object(obj->idx.offset, _("delta base offset is out of bound"));
 459                 break;
 460         case OBJ_COMMIT:
 461         case OBJ_TREE:
 462         case OBJ_BLOB:
 463         case OBJ_TAG:
 464                 break;
 465         default:
 466                 bad_object(obj->idx.offset, _("unknown object type %d"), obj->type);
 467         }
 468         obj->hdr_size = consumed_bytes - obj->idx.offset;
 469
 470         data = unpack_entry_data(obj->idx.offset, obj->size);
 471         obj->idx.crc32 = input_crc32;
 472         return data;
 473 }
 474
 475 static void *get_data_from_pack(struct object_entry *obj)
 476 {
 477         off_t from = obj[0].idx.offset + obj[0].hdr_size;
 478         unsigned long len = obj[1].idx.offset - from;
 479         unsigned char *data, *inbuf;
 480         git_zstream stream;
 481         int status;
 482
 483         data = xmalloc(obj->size);
 484         inbuf = xmalloc((len < 64*1024) ? len : 64*1024);
 485
 486         memset(&stream, 0, sizeof(stream));
 487         git_inflate_init(&stream);
 488         stream.next_out = data;
 489         stream.avail_out = obj->size;
 490
 491         do {
 492                 ssize_t n = (len < 64*1024) ? len : 64*1024;
 493                 n = pread(pack_fd, inbuf, n, from);
 494                 if (n < 0)
 495                         die_errno(_("cannot pread pack file"));
 496                 if (!n)
 497                         die(Q_("premature end of pack file, %lu byte missing",
 498                                "premature end of pack file, %lu bytes missing",
 499                                len),
 500                             len);
 501                 from += n;
 502                 len -= n;
 503                 stream.next_in = inbuf;
 504                 stream.avail_in = n;
 505                 status = git_inflate(&stream, 0);
 506         } while (len && status == Z_OK && !stream.avail_in);
 507
 508         /* This has been inflated OK when first encountered, so... */
 509         if (status != Z_STREAM_END || stream.total_out != obj->size)
 510                 die(_("serious inflate inconsistency"));
 511
 512         git_inflate_end(&stream);
 513         free(inbuf);
 514         return data;
 515 }
 516
 517 static int compare_delta_bases(const union delta_base *base1,
 518                                const union delta_base *base2,
 519                                enum object_type type1,
 520                                enum object_type type2)
 521 {
 522         int cmp = type1 - type2;
 523         if (cmp)
 524                 return cmp;
 525         return memcmp(base1, base2, UNION_BASE_SZ);
 526 }
 527
 528 static int find_delta(const union delta_base *base, enum object_type type)
 529 {
 530         int first = 0, last = nr_deltas;
 531
 532         while (first < last) {
 533                 int next = (first + last) / 2;
 534                 struct delta_entry *delta = &deltas[next];
 535                 int cmp;
 536
 537                 cmp = compare_delta_bases(base, &delta->base,
 538                                           type, objects[delta->obj_no].type);
 539                 if (!cmp)
 540                         return next;
 541                 if (cmp < 0) {
 542                         last = next;
 543                         continue;
 544                 }
 545                 first = next+1;
 546         }
 547         return -first-1;
 548 }
 549
 550 static void find_delta_children(const union delta_base *base,
 551                                 int *first_index, int *last_index,
 552                                 enum object_type type)
 553 {
 554         int first = find_delta(base, type);
 555         int last = first;
 556         int end = nr_deltas - 1;
 557
 558         if (first < 0) {
 559                 *first_index = 0;
 560                 *last_index = -1;
 561                 return;
 562         }
 563         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
 564                 --first;
 565         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
 566                 ++last;
 567         *first_index = first;
 568         *last_index = last;
 569 }
 570
 571 static void sha1_object(const void *data, unsigned long size,
 572                         enum object_type type, unsigned char *sha1)
 573 {
 574         hash_sha1_file(data, size, typename(type), sha1);
 575         read_lock();
 576         if (has_sha1_file(sha1)) {
 577                 void *has_data;
 578                 enum object_type has_type;
 579                 unsigned long has_size;
 580                 has_data = read_sha1_file(sha1, &has_type, &has_size);
 581                 read_unlock();
 582                 if (!has_data)
 583                         die(_("cannot read existing object %s"), sha1_to_hex(sha1));
 584                 if (size != has_size || type != has_type ||
 585                     memcmp(data, has_data, size) != 0)
 586                         die(_("SHA1 COLLISION FOUND WITH %s !"), sha1_to_hex(sha1));
 587                 free(has_data);
 588         } else
 589                 read_unlock();
 590
 591         if (strict) {
 592                 read_lock();
 593                 if (type == OBJ_BLOB) {
 594                         struct blob *blob = lookup_blob(sha1);
 595                         if (blob)
 596                                 blob->object.flags |= FLAG_CHECKED;
 597                         else
 598                                 die(_("invalid blob object %s"), sha1_to_hex(sha1));
 599                 } else {
 600                         struct object *obj;
 601                         int eaten;
 602                         void *buf = (void *) data;
 603
 604                         /*
 605                          * we do not need to free the memory here, as the
 606                          * buf is deleted by the caller.
 607                          */
 608                         obj = parse_object_buffer(sha1, type, size, buf, &eaten);
 609                         if (!obj)
 610                                 die(_("invalid %s"), typename(type));
 611                         if (fsck_object(obj, 1, fsck_error_function))
 612                                 die(_("Error in object"));
 613                         if (fsck_walk(obj, mark_link, NULL))
 614                                 die(_("Not all child objects of %s are reachable"), sha1_to_hex(obj->sha1));
 615
 616                         if (obj->type == OBJ_TREE) {
 617                                 struct tree *item = (struct tree *) obj;
 618                                 item->buffer = NULL;
 619                         }
 620                         if (obj->type == OBJ_COMMIT) {
 621                                 struct commit *commit = (struct commit *) obj;
 622                                 commit->buffer = NULL;
 623                         }
 624                         obj->flags |= FLAG_CHECKED;
 625                 }
 626                 read_unlock();
 627         }
 628 }
 629
 630 static int is_delta_type(enum object_type type)
 631 {
 632         return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
 633 }
 634
 635 /*
 636  * This function is part of find_unresolved_deltas(). There are two
 637  * walkers going in the opposite ways.
 638  *
 639  * The first one in find_unresolved_deltas() traverses down from
 640  * parent node to children, deflating nodes along the way. However,
 641  * memory for deflated nodes is limited by delta_base_cache_limit, so
 642  * at some point parent node's deflated content may be freed.
 643  *
 644  * The second walker is this function, which goes from current node up
 645  * to top parent if necessary to deflate the node. In normal
 646  * situation, its parent node would be already deflated, so it just
 647  * needs to apply delta.
 648  *
 649  * In the worst case scenario, parent node is no longer deflated because
 650  * we're running out of delta_base_cache_limit; we need to re-deflate
 651  * parents, possibly up to the top base.
 652  *
 653  * All deflated objects here are subject to be freed if we exceed
 654  * delta_base_cache_limit, just like in find_unresolved_deltas(), we
 655  * just need to make sure the last node is not freed.
 656  */
 657 static void *get_base_data(struct base_data *c)
 658 {
 659         if (!c->data) {
 660                 struct object_entry *obj = c->obj;
 661                 struct base_data **delta = NULL;
 662                 int delta_nr = 0, delta_alloc = 0;
 663
 664                 while (is_delta_type(c->obj->type) && !c->data) {
 665                         ALLOC_GROW(delta, delta_nr + 1, delta_alloc);
 666                         delta[delta_nr++] = c;
 667                         c = c->base;
 668                 }
 669                 if (!delta_nr) {
 670                         c->data = get_data_from_pack(obj);
 671                         c->size = obj->size;
 672                         get_thread_data()->base_cache_used += c->size;
 673                         prune_base_data(c);
 674                 }
 675                 for (; delta_nr > 0; delta_nr--) {
 676                         void *base, *raw;
 677                         c = delta[delta_nr - 1];
 678                         obj = c->obj;
 679                         base = get_base_data(c->base);
 680                         raw = get_data_from_pack(obj);
 681                         c->data = patch_delta(
 682                                 base, c->base->size,
 683                                 raw, obj->size,
 684                                 &c->size);
 685                         free(raw);
 686                         if (!c->data)
 687                                 bad_object(obj->idx.offset, _("failed to apply delta"));
 688                         get_thread_data()->base_cache_used += c->size;
 689                         prune_base_data(c);
 690                 }
 691                 free(delta);
 692         }
 693         return c->data;
 694 }
 695
 696 static void resolve_delta(struct object_entry *delta_obj,
 697                           struct base_data *base, struct base_data *result)
 698 {
 699         void *base_data, *delta_data;
 700
 701         delta_obj->real_type = base->obj->real_type;
 702         delta_obj->delta_depth = base->obj->delta_depth + 1;
 703         if (deepest_delta < delta_obj->delta_depth)
 704                 deepest_delta = delta_obj->delta_depth;
 705         delta_obj->base_object_no = base->obj - objects;
 706         delta_data = get_data_from_pack(delta_obj);
 707         base_data = get_base_data(base);
 708         result->obj = delta_obj;
 709         result->data = patch_delta(base_data, base->size,
 710                                    delta_data, delta_obj->size, &result->size);
 711         free(delta_data);
 712         if (!result->data)
 713                 bad_object(delta_obj->idx.offset, _("failed to apply delta"));
 714         sha1_object(result->data, result->size, delta_obj->real_type,
 715                     delta_obj->idx.sha1);
 716         counter_lock();
 717         nr_resolved_deltas++;
 718         counter_unlock();
 719 }
 720
 721 static struct base_data *find_unresolved_deltas_1(struct base_data *base,
 722                                                   struct base_data *prev_base)
 723 {
 724         if (base->ref_last == -1 && base->ofs_last == -1) {
 725                 union delta_base base_spec;
 726
 727                 hashcpy(base_spec.sha1, base->obj->idx.sha1);
 728                 find_delta_children(&base_spec,
 729                                     &base->ref_first, &base->ref_last, OBJ_REF_DELTA);
 730
 731                 memset(&base_spec, 0, sizeof(base_spec));
 732                 base_spec.offset = base->obj->idx.offset;
 733                 find_delta_children(&base_spec,
 734                                     &base->ofs_first, &base->ofs_last, OBJ_OFS_DELTA);
 735
 736                 if (base->ref_last == -1 && base->ofs_last == -1) {
 737                         free(base->data);
 738                         return NULL;
 739                 }
 740
 741                 link_base_data(prev_base, base);
 742         }
 743
 744         if (base->ref_first <= base->ref_last) {
 745                 struct object_entry *child = objects + deltas[base->ref_first].obj_no;
 746                 struct base_data *result = alloc_base_data();
 747
 748                 assert(child->real_type == OBJ_REF_DELTA);
 749                 resolve_delta(child, base, result);
 750                 if (base->ref_first == base->ref_last && base->ofs_last == -1)
 751                         free_base_data(base);
 752
 753                 base->ref_first++;
 754                 return result;
 755         }
 756
 757         if (base->ofs_first <= base->ofs_last) {
 758                 struct object_entry *child = objects + deltas[base->ofs_first].obj_no;
 759                 struct base_data *result = alloc_base_data();
 760
 761                 assert(child->real_type == OBJ_OFS_DELTA);
 762                 resolve_delta(child, base, result);
 763                 if (base->ofs_first == base->ofs_last)
 764                         free_base_data(base);
 765
 766                 base->ofs_first++;
 767                 return result;
 768         }
 769
 770         unlink_base_data(base);
 771         return NULL;
 772 }
 773
 774 static void find_unresolved_deltas(struct base_data *base)
 775 {
 776         struct base_data *new_base, *prev_base = NULL;
 777         for (;;) {
 778                 new_base = find_unresolved_deltas_1(base, prev_base);
 779
 780                 if (new_base) {
 781                         prev_base = base;
 782                         base = new_base;
 783                 } else {
 784                         free(base);
 785                         base = prev_base;
 786                         if (!base)
 787                                 return;
 788                         prev_base = base->base;
 789                 }
 790         }
 791 }
 792
 793 static int compare_delta_entry(const void *a, const void *b)
 794 {
 795         const struct delta_entry *delta_a = a;
 796         const struct delta_entry *delta_b = b;
 797
 798         /* group by type (ref vs ofs) and then by value (sha-1 or offset) */
 799         return compare_delta_bases(&delta_a->base, &delta_b->base,
 800                                    objects[delta_a->obj_no].type,
 801                                    objects[delta_b->obj_no].type);
 802 }
 803
 804 static void resolve_base(struct object_entry *obj)
 805 {
 806         struct base_data *base_obj = alloc_base_data();
 807         base_obj->obj = obj;
 808         base_obj->data = NULL;
 809         find_unresolved_deltas(base_obj);
 810 }
 811
 812 #ifndef NO_PTHREADS
 813 static void *threaded_second_pass(void *data)
 814 {
 815         set_thread_data(data);
 816         for (;;) {
 817                 int i;
 818                 work_lock();
 819                 display_progress(progress, nr_resolved_deltas);
 820                 while (nr_dispatched < nr_objects &&
 821                        is_delta_type(objects[nr_dispatched].type))
 822                         nr_dispatched++;
 823                 if (nr_dispatched >= nr_objects) {
 824                         work_unlock();
 825                         break;
 826                 }
 827                 i = nr_dispatched++;
 828                 work_unlock();
 829
 830                 resolve_base(&objects[i]);
 831         }
 832         return NULL;
 833 }
 834 #endif
 835
 836 /*
 837  * First pass:
 838  * - find locations of all objects;
 839  * - calculate SHA1 of all non-delta objects;
 840  * - remember base (SHA1 or offset) for all deltas.
 841  */
 842 static void parse_pack_objects(unsigned char *sha1)
 843 {
 844         int i;
 845         struct delta_entry *delta = deltas;
 846         struct stat st;
 847
 848         if (verbose)
 849                 progress = start_progress(
 850                                 from_stdin ? _("Receiving objects") : _("Indexing objects"),
 851                                 nr_objects);
 852         for (i = 0; i < nr_objects; i++) {
 853                 struct object_entry *obj = &objects[i];
 854                 void *data = unpack_raw_entry(obj, &delta->base);
 855                 obj->real_type = obj->type;
 856                 if (is_delta_type(obj->type)) {
 857                         nr_deltas++;
 858                         delta->obj_no = i;
 859                         delta++;
 860                 } else
 861                         sha1_object(data, obj->size, obj->type, obj->idx.sha1);
 862                 free(data);
 863                 display_progress(progress, i+1);
 864         }
 865         objects[i].idx.offset = consumed_bytes;
 866         stop_progress(&progress);
 867
 868         /* Check pack integrity */
 869         flush();
 870         git_SHA1_Final(sha1, &input_ctx);
 871         if (hashcmp(fill(20), sha1))
 872                 die(_("pack is corrupted (SHA1 mismatch)"));
 873         use(20);
 874
 875         /* If input_fd is a file, we should have reached its end now. */
 876         if (fstat(input_fd, &st))
 877                 die_errno(_("cannot fstat packfile"));
 878         if (S_ISREG(st.st_mode) &&
 879                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
 880                 die(_("pack has junk at the end"));
 881 }
 882
 883 /*
 884  * Second pass:
 885  * - for all non-delta objects, look if it is used as a base for
 886  *   deltas;
 887  * - if used as a base, uncompress the object and apply all deltas,
 888  *   recursively checking if the resulting object is used as a base
 889  *   for some more deltas.
 890  */
 891 static void resolve_deltas(void)
 892 {
 893         int i;
 894
 895         if (!nr_deltas)
 896                 return;
 897
 898         /* Sort deltas by base SHA1/offset for fast searching */
 899         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
 900               compare_delta_entry);
 901
 902         if (verbose)
 903                 progress = start_progress(_("Resolving deltas"), nr_deltas);
 904
 905 #ifndef NO_PTHREADS
 906         nr_dispatched = 0;
 907         if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) {
 908                 init_thread();
 909                 for (i = 0; i < nr_threads; i++) {
 910                         int ret = pthread_create(&thread_data[i].thread, NULL,
 911                                                  threaded_second_pass, thread_data + i);
 912                         if (ret)
 913                                 die("unable to create thread: %s", strerror(ret));
 914                 }
 915                 for (i = 0; i < nr_threads; i++)
 916                         pthread_join(thread_data[i].thread, NULL);
 917                 cleanup_thread();
 918                 return;
 919         }
 920 #endif
 921
 922         for (i = 0; i < nr_objects; i++) {
 923                 struct object_entry *obj = &objects[i];
 924
 925                 if (is_delta_type(obj->type))
 926                         continue;
 927                 resolve_base(obj);
 928                 display_progress(progress, nr_resolved_deltas);
 929         }
 930 }
 931
 932 /*
 933  * Third pass:
 934  * - append objects to convert thin pack to full pack if required
 935  * - write the final 20-byte SHA-1
 936  */
 937 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved);
 938 static void conclude_pack(int fix_thin_pack, const char *curr_pack, unsigned char *pack_sha1)
 939 {
 940         if (nr_deltas == nr_resolved_deltas) {
 941                 stop_progress(&progress);
 942                 /* Flush remaining pack final 20-byte SHA1. */
 943                 flush();
 944                 return;
 945         }
 946
 947         if (fix_thin_pack) {
 948                 struct sha1file *f;
 949                 unsigned char read_sha1[20], tail_sha1[20];
 950                 char msg[48];
 951                 int nr_unresolved = nr_deltas - nr_resolved_deltas;
 952                 int nr_objects_initial = nr_objects;
 953                 if (nr_unresolved <= 0)
 954                         die(_("confusion beyond insanity"));
 955                 objects = xrealloc(objects,
 956                                    (nr_objects + nr_unresolved + 1)
 957                                    * sizeof(*objects));
 958                 f = sha1fd(output_fd, curr_pack);
 959                 fix_unresolved_deltas(f, nr_unresolved);
 960                 sprintf(msg, "completed with %d local objects",
 961                         nr_objects - nr_objects_initial);
 962                 stop_progress_msg(&progress, msg);
 963                 sha1close(f, tail_sha1, 0);
 964                 hashcpy(read_sha1, pack_sha1);
 965                 fixup_pack_header_footer(output_fd, pack_sha1,
 966                                          curr_pack, nr_objects,
 967                                          read_sha1, consumed_bytes-20);
 968                 if (hashcmp(read_sha1, tail_sha1) != 0)
 969                         die("Unexpected tail checksum for %s "
 970                             "(disk corruption?)", curr_pack);
 971         }
 972         if (nr_deltas != nr_resolved_deltas)
 973                 die(Q_("pack has %d unresolved delta",
 974                        "pack has %d unresolved deltas",
 975                        nr_deltas - nr_resolved_deltas),
 976                     nr_deltas - nr_resolved_deltas);
 977 }
 978
 979 static int write_compressed(struct sha1file *f, void *in, unsigned int size)
 980 {
 981         git_zstream stream;
 982         int status;
 983         unsigned char outbuf[4096];
 984
 985         memset(&stream, 0, sizeof(stream));
 986         git_deflate_init(&stream, zlib_compression_level);
 987         stream.next_in = in;
 988         stream.avail_in = size;
 989
 990         do {
 991                 stream.next_out = outbuf;
 992                 stream.avail_out = sizeof(outbuf);
 993                 status = git_deflate(&stream, Z_FINISH);
 994                 sha1write(f, outbuf, sizeof(outbuf) - stream.avail_out);
 995         } while (status == Z_OK);
 996
 997         if (status != Z_STREAM_END)
 998                 die(_("unable to deflate appended object (%d)"), status);
 999         size = stream.total_out;
1000         git_deflate_end(&stream);
1001         return size;
1002 }
1003
1004 static struct object_entry *append_obj_to_pack(struct sha1file *f,
1005                                const unsigned char *sha1, void *buf,
1006                                unsigned long size, enum object_type type)
1007 {
1008         struct object_entry *obj = &objects[nr_objects++];
1009         unsigned char header[10];
1010         unsigned long s = size;
1011         int n = 0;
1012         unsigned char c = (type << 4) | (s & 15);
1013         s >>= 4;
1014         while (s) {
1015                 header[n++] = c | 0x80;
1016                 c = s & 0x7f;
1017                 s >>= 7;
1018         }
1019         header[n++] = c;
1020         crc32_begin(f);
1021         sha1write(f, header, n);
1022         obj[0].size = size;
1023         obj[0].hdr_size = n;
1024         obj[0].type = type;
1025         obj[0].real_type = type;
1026         obj[1].idx.offset = obj[0].idx.offset + n;
1027         obj[1].idx.offset += write_compressed(f, buf, size);
1028         obj[0].idx.crc32 = crc32_end(f);
1029         sha1flush(f);
1030         hashcpy(obj->idx.sha1, sha1);
1031         return obj;
1032 }
1033
1034 static int delta_pos_compare(const void *_a, const void *_b)
1035 {
1036         struct delta_entry *a = *(struct delta_entry **)_a;
1037         struct delta_entry *b = *(struct delta_entry **)_b;
1038         return a->obj_no - b->obj_no;
1039 }
1040
1041 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
1042 {
1043         struct delta_entry **sorted_by_pos;
1044         int i, n = 0;
1045
1046         /*
1047          * Since many unresolved deltas may well be themselves base objects
1048          * for more unresolved deltas, we really want to include the
1049          * smallest number of base objects that would cover as much delta
1050          * as possible by picking the
1051          * trunc deltas first, allowing for other deltas to resolve without
1052          * additional base objects.  Since most base objects are to be found
1053          * before deltas depending on them, a good heuristic is to start
1054          * resolving deltas in the same order as their position in the pack.
1055          */
1056         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
1057         for (i = 0; i < nr_deltas; i++) {
1058                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
1059                         continue;
1060                 sorted_by_pos[n++] = &deltas[i];
1061         }
1062         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
1063
1064         for (i = 0; i < n; i++) {
1065                 struct delta_entry *d = sorted_by_pos[i];
1066                 enum object_type type;
1067                 struct base_data *base_obj = alloc_base_data();
1068
1069                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
1070                         continue;
1071                 base_obj->data = read_sha1_file(d->base.sha1, &type, &base_obj->size);
1072                 if (!base_obj->data)
1073                         continue;
1074
1075                 if (check_sha1_signature(d->base.sha1, base_obj->data,
1076                                 base_obj->size, typename(type)))
1077                         die(_("local object %s is corrupt"), sha1_to_hex(d->base.sha1));
1078                 base_obj->obj = append_obj_to_pack(f, d->base.sha1,
1079                                         base_obj->data, base_obj->size, type);
1080                 find_unresolved_deltas(base_obj);
1081                 display_progress(progress, nr_resolved_deltas);
1082         }
1083         free(sorted_by_pos);
1084 }
1085
1086 static void final(const char *final_pack_name, const char *curr_pack_name,
1087                   const char *final_index_name, const char *curr_index_name,
1088                   const char *keep_name, const char *keep_msg,
1089                   unsigned char *sha1)
1090 {
1091         const char *report = "pack";
1092         char name[PATH_MAX];
1093         int err;
1094
1095         if (!from_stdin) {
1096                 close(input_fd);
1097         } else {
1098                 fsync_or_die(output_fd, curr_pack_name);
1099                 err = close(output_fd);
1100                 if (err)
1101                         die_errno(_("error while closing pack file"));
1102         }
1103
1104         if (keep_msg) {
1105                 int keep_fd, keep_msg_len = strlen(keep_msg);
1106
1107                 if (!keep_name)
1108                         keep_fd = odb_pack_keep(name, sizeof(name), sha1);
1109                 else
1110                         keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
1111
1112                 if (keep_fd < 0) {
1113                         if (errno != EEXIST)
1114                                 die_errno(_("cannot write keep file '%s'"),
1115                                           keep_name);
1116                 } else {
1117                         if (keep_msg_len > 0) {
1118                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
1119                                 write_or_die(keep_fd, "\n", 1);
1120                         }
1121                         if (close(keep_fd) != 0)
1122                                 die_errno(_("cannot close written keep file '%s'"),
1123                                     keep_name);
1124                         report = "keep";
1125                 }
1126         }
1127
1128         if (final_pack_name != curr_pack_name) {
1129                 if (!final_pack_name) {
1130                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
1131                                  get_object_directory(), sha1_to_hex(sha1));
1132                         final_pack_name = name;
1133                 }
1134                 if (move_temp_to_file(curr_pack_name, final_pack_name))
1135                         die(_("cannot store pack file"));
1136         } else if (from_stdin)
1137                 chmod(final_pack_name, 0444);
1138
1139         if (final_index_name != curr_index_name) {
1140                 if (!final_index_name) {
1141                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
1142                                  get_object_directory(), sha1_to_hex(sha1));
1143                         final_index_name = name;
1144                 }
1145                 if (move_temp_to_file(curr_index_name, final_index_name))
1146                         die(_("cannot store index file"));
1147         } else
1148                 chmod(final_index_name, 0444);
1149
1150         if (!from_stdin) {
1151                 printf("%s\n", sha1_to_hex(sha1));
1152         } else {
1153                 char buf[48];
1154                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
1155                                    report, sha1_to_hex(sha1));
1156                 write_or_die(1, buf, len);
1157
1158                 /*
1159                  * Let's just mimic git-unpack-objects here and write
1160                  * the last part of the input buffer to stdout.
1161                  */
1162                 while (input_len) {
1163                         err = xwrite(1, input_buffer + input_offset, input_len);
1164                         if (err <= 0)
1165                                 break;
1166                         input_len -= err;
1167                         input_offset += err;
1168                 }
1169         }
1170 }
1171
1172 static int git_index_pack_config(const char *k, const char *v, void *cb)
1173 {
1174         struct pack_idx_option *opts = cb;
1175
1176         if (!strcmp(k, "pack.indexversion")) {
1177                 opts->version = git_config_int(k, v);
1178                 if (opts->version > 2)
1179                         die("bad pack.indexversion=%"PRIu32, opts->version);
1180                 return 0;
1181         }
1182         if (!strcmp(k, "pack.threads")) {
1183                 nr_threads = git_config_int(k, v);
1184                 if (nr_threads < 0)
1185                         die("invalid number of threads specified (%d)",
1186                             nr_threads);
1187 #ifdef NO_PTHREADS
1188                 if (nr_threads != 1)
1189                         warning("no threads support, ignoring %s", k);
1190                 nr_threads = 1;
1191 #endif
1192                 return 0;
1193         }
1194         return git_default_config(k, v, cb);
1195 }
1196
1197 static int cmp_uint32(const void *a_, const void *b_)
1198 {
1199         uint32_t a = *((uint32_t *)a_);
1200         uint32_t b = *((uint32_t *)b_);
1201
1202         return (a < b) ? -1 : (a != b);
1203 }
1204
1205 static void read_v2_anomalous_offsets(struct packed_git *p,
1206                                       struct pack_idx_option *opts)
1207 {
1208         const uint32_t *idx1, *idx2;
1209         uint32_t i;
1210
1211         /* The address of the 4-byte offset table */
1212         idx1 = (((const uint32_t *)p->index_data)
1213                 + 2 /* 8-byte header */
1214                 + 256 /* fan out */
1215                 + 5 * p->num_objects /* 20-byte SHA-1 table */
1216                 + p->num_objects /* CRC32 table */
1217                 );
1218
1219         /* The address of the 8-byte offset table */
1220         idx2 = idx1 + p->num_objects;
1221
1222         for (i = 0; i < p->num_objects; i++) {
1223                 uint32_t off = ntohl(idx1[i]);
1224                 if (!(off & 0x80000000))
1225                         continue;
1226                 off = off & 0x7fffffff;
1227                 if (idx2[off * 2])
1228                         continue;
1229                 /*
1230                  * The real offset is ntohl(idx2[off * 2]) in high 4
1231                  * octets, and ntohl(idx2[off * 2 + 1]) in low 4
1232                  * octets.  But idx2[off * 2] is Zero!!!
1233                  */
1234                 ALLOC_GROW(opts->anomaly, opts->anomaly_nr + 1, opts->anomaly_alloc);
1235                 opts->anomaly[opts->anomaly_nr++] = ntohl(idx2[off * 2 + 1]);
1236         }
1237
1238         if (1 < opts->anomaly_nr)
1239                 qsort(opts->anomaly, opts->anomaly_nr, sizeof(uint32_t), cmp_uint32);
1240 }
1241
1242 static void read_idx_option(struct pack_idx_option *opts, const char *pack_name)
1243 {
1244         struct packed_git *p = add_packed_git(pack_name, strlen(pack_name), 1);
1245
1246         if (!p)
1247                 die(_("Cannot open existing pack file '%s'"), pack_name);
1248         if (open_pack_index(p))
1249                 die(_("Cannot open existing pack idx file for '%s'"), pack_name);
1250
1251         /* Read the attributes from the existing idx file */
1252         opts->version = p->index_version;
1253
1254         if (opts->version == 2)
1255                 read_v2_anomalous_offsets(p, opts);
1256
1257         /*
1258          * Get rid of the idx file as we do not need it anymore.
1259          * NEEDSWORK: extract this bit from free_pack_by_name() in
1260          * sha1_file.c, perhaps?  It shouldn't matter very much as we
1261          * know we haven't installed this pack (hence we never have
1262          * read anything from it).
1263          */
1264         close_pack_index(p);
1265         free(p);
1266 }
1267
1268 static void show_pack_info(int stat_only)
1269 {
1270         int i, baseobjects = nr_objects - nr_deltas;
1271         unsigned long *chain_histogram = NULL;
1272
1273         if (deepest_delta)
1274                 chain_histogram = xcalloc(deepest_delta, sizeof(unsigned long));
1275
1276         for (i = 0; i < nr_objects; i++) {
1277                 struct object_entry *obj = &objects[i];
1278
1279                 if (is_delta_type(obj->type))
1280                         chain_histogram[obj->delta_depth - 1]++;
1281                 if (stat_only)
1282                         continue;
1283                 printf("%s %-6s %lu %lu %"PRIuMAX,
1284                        sha1_to_hex(obj->idx.sha1),
1285                        typename(obj->real_type), obj->size,
1286                        (unsigned long)(obj[1].idx.offset - obj->idx.offset),
1287                        (uintmax_t)obj->idx.offset);
1288                 if (is_delta_type(obj->type)) {
1289                         struct object_entry *bobj = &objects[obj->base_object_no];
1290                         printf(" %u %s", obj->delta_depth, sha1_to_hex(bobj->idx.sha1));
1291                 }
1292                 putchar('\n');
1293         }
1294
1295         if (baseobjects)
1296                 printf_ln(Q_("non delta: %d object",
1297                              "non delta: %d objects",
1298                              baseobjects),
1299                           baseobjects);
1300         for (i = 0; i < deepest_delta; i++) {
1301                 if (!chain_histogram[i])
1302                         continue;
1303                 printf_ln(Q_("chain length = %d: %lu object",
1304                              "chain length = %d: %lu objects",
1305                              chain_histogram[i]),
1306                           i + 1,
1307                           chain_histogram[i]);
1308         }
1309 }
1310
1311 int cmd_index_pack(int argc, const char **argv, const char *prefix)
1312 {
1313         int i, fix_thin_pack = 0, verify = 0, stat_only = 0, stat = 0;
1314         const char *curr_pack, *curr_index;
1315         const char *index_name = NULL, *pack_name = NULL;
1316         const char *keep_name = NULL, *keep_msg = NULL;
1317         char *index_name_buf = NULL, *keep_name_buf = NULL;
1318         struct pack_idx_entry **idx_objects;
1319         struct pack_idx_option opts;
1320         unsigned char pack_sha1[20];
1321
1322         if (argc == 2 && !strcmp(argv[1], "-h"))
1323                 usage(index_pack_usage);
1324
1325         read_replace_refs = 0;
1326
1327         reset_pack_idx_option(&opts);
1328         git_config(git_index_pack_config, &opts);
1329         if (prefix && chdir(prefix))
1330                 die(_("Cannot come back to cwd"));
1331
1332         for (i = 1; i < argc; i++) {
1333                 const char *arg = argv[i];
1334
1335                 if (*arg == '-') {
1336                         if (!strcmp(arg, "--stdin")) {
1337                                 from_stdin = 1;
1338                         } else if (!strcmp(arg, "--fix-thin")) {
1339                                 fix_thin_pack = 1;
1340                         } else if (!strcmp(arg, "--strict")) {
1341                                 strict = 1;
1342                         } else if (!strcmp(arg, "--verify")) {
1343                                 verify = 1;
1344                         } else if (!strcmp(arg, "--verify-stat")) {
1345                                 verify = 1;
1346                                 stat = 1;
1347                         } else if (!strcmp(arg, "--verify-stat-only")) {
1348                                 verify = 1;
1349                                 stat = 1;
1350                                 stat_only = 1;
1351                         } else if (!strcmp(arg, "--keep")) {
1352                                 keep_msg = "";
1353                         } else if (!prefixcmp(arg, "--keep=")) {
1354                                 keep_msg = arg + 7;
1355                         } else if (!prefixcmp(arg, "--threads=")) {
1356                                 char *end;
1357                                 nr_threads = strtoul(arg+10, &end, 0);
1358                                 if (!arg[10] || *end || nr_threads < 0)
1359                                         usage(index_pack_usage);
1360 #ifdef NO_PTHREADS
1361                                 if (nr_threads != 1)
1362                                         warning("no threads support, "
1363                                                 "ignoring %s", arg);
1364                                 nr_threads = 1;
1365 #endif
1366                         } else if (!prefixcmp(arg, "--pack_header=")) {
1367                                 struct pack_header *hdr;
1368                                 char *c;
1369
1370                                 hdr = (struct pack_header *)input_buffer;
1371                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
1372                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
1373                                 if (*c != ',')
1374                                         die(_("bad %s"), arg);
1375                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
1376                                 if (*c)
1377                                         die(_("bad %s"), arg);
1378                                 input_len = sizeof(*hdr);
1379                         } else if (!strcmp(arg, "-v")) {
1380                                 verbose = 1;
1381                         } else if (!strcmp(arg, "-o")) {
1382                                 if (index_name || (i+1) >= argc)
1383                                         usage(index_pack_usage);
1384                                 index_name = argv[++i];
1385                         } else if (!prefixcmp(arg, "--index-version=")) {
1386                                 char *c;
1387                                 opts.version = strtoul(arg + 16, &c, 10);
1388                                 if (opts.version > 2)
1389                                         die(_("bad %s"), arg);
1390                                 if (*c == ',')
1391                                         opts.off32_limit = strtoul(c+1, &c, 0);
1392                                 if (*c || opts.off32_limit & 0x80000000)
1393                                         die(_("bad %s"), arg);
1394                         } else
1395                                 usage(index_pack_usage);
1396                         continue;
1397                 }
1398
1399                 if (pack_name)
1400                         usage(index_pack_usage);
1401                 pack_name = arg;
1402         }
1403
1404         if (!pack_name && !from_stdin)
1405                 usage(index_pack_usage);
1406         if (fix_thin_pack && !from_stdin)
1407                 die(_("--fix-thin cannot be used without --stdin"));
1408         if (!index_name && pack_name) {
1409                 int len = strlen(pack_name);
1410                 if (!has_extension(pack_name, ".pack"))
1411                         die(_("packfile name '%s' does not end with '.pack'"),
1412                             pack_name);
1413                 index_name_buf = xmalloc(len);
1414                 memcpy(index_name_buf, pack_name, len - 5);
1415                 strcpy(index_name_buf + len - 5, ".idx");
1416                 index_name = index_name_buf;
1417         }
1418         if (keep_msg && !keep_name && pack_name) {
1419                 int len = strlen(pack_name);
1420                 if (!has_extension(pack_name, ".pack"))
1421                         die(_("packfile name '%s' does not end with '.pack'"),
1422                             pack_name);
1423                 keep_name_buf = xmalloc(len);
1424                 memcpy(keep_name_buf, pack_name, len - 5);
1425                 strcpy(keep_name_buf + len - 5, ".keep");
1426                 keep_name = keep_name_buf;
1427         }
1428         if (verify) {
1429                 if (!index_name)
1430                         die(_("--verify with no packfile name given"));
1431                 read_idx_option(&opts, index_name);
1432                 opts.flags |= WRITE_IDX_VERIFY | WRITE_IDX_STRICT;
1433         }
1434         if (strict)
1435                 opts.flags |= WRITE_IDX_STRICT;
1436
1437 #ifndef NO_PTHREADS
1438         if (!nr_threads) {
1439                 nr_threads = online_cpus();
1440                 /* An experiment showed that more threads does not mean faster */
1441                 if (nr_threads > 3)
1442                         nr_threads = 3;
1443         }
1444 #endif
1445
1446         curr_pack = open_pack_file(pack_name);
1447         parse_pack_header();
1448         objects = xcalloc(nr_objects + 1, sizeof(struct object_entry));
1449         deltas = xcalloc(nr_objects, sizeof(struct delta_entry));
1450         parse_pack_objects(pack_sha1);
1451         resolve_deltas();
1452         conclude_pack(fix_thin_pack, curr_pack, pack_sha1);
1453         free(deltas);
1454         if (strict)
1455                 check_objects();
1456
1457         if (stat)
1458                 show_pack_info(stat_only);
1459
1460         idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
1461         for (i = 0; i < nr_objects; i++)
1462                 idx_objects[i] = &objects[i].idx;
1463         curr_index = write_idx_file(index_name, idx_objects, nr_objects, &opts, pack_sha1);
1464         free(idx_objects);
1465
1466         if (!verify)
1467                 final(pack_name, curr_pack,
1468                       index_name, curr_index,
1469                       keep_name, keep_msg,
1470                       pack_sha1);
1471         else
1472                 close(input_fd);
1473         free(objects);
1474         free(index_name_buf);
1475         free(keep_name_buf);
1476         if (pack_name == NULL)
1477                 free((void *) curr_pack);
1478         if (index_name == NULL)
1479                 free((void *) curr_index);
1480
1481         return 0;
1482 }