git.oblomov.eu Git - git/blob - builtin/index-pack.c

   1 #include "builtin.h"
   2 #include "config.h"
   3 #include "delta.h"
   4 #include "pack.h"
   5 #include "csum-file.h"
   6 #include "blob.h"
   7 #include "commit.h"
   8 #include "tag.h"
   9 #include "tree.h"
  10 #include "progress.h"
  11 #include "fsck.h"
  12 #include "exec-cmd.h"
  13 #include "streaming.h"
  14 #include "thread-utils.h"
  15 #include "packfile.h"
  16 #include "object-store.h"
  17 #include "promisor-remote.h"
  18
  19 static const char index_pack_usage[] =
  20 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
  21
  22 struct object_entry {
  23         struct pack_idx_entry idx;
  24         unsigned long size;
  25         unsigned char hdr_size;
  26         signed char type;
  27         signed char real_type;
  28 };
  29
  30 struct object_stat {
  31         unsigned delta_depth;
  32         int base_object_no;
  33 };
  34
  35 struct base_data {
  36         /* Initialized by make_base(). */
  37         struct base_data *base;
  38         struct object_entry *obj;
  39         int ref_first, ref_last;
  40         int ofs_first, ofs_last;
  41
  42         /* Not initialized by make_base(). */
  43         void *data;
  44         unsigned long size;
  45 };
  46
  47 struct thread_local {
  48         pthread_t thread;
  49         size_t base_cache_used;
  50         int pack_fd;
  51 };
  52
  53 /* Remember to update object flag allocation in object.h */
  54 #define FLAG_LINK (1u<<20)
  55 #define FLAG_CHECKED (1u<<21)
  56
  57 struct ofs_delta_entry {
  58         off_t offset;
  59         int obj_no;
  60 };
  61
  62 struct ref_delta_entry {
  63         struct object_id oid;
  64         int obj_no;
  65 };
  66
  67 static struct object_entry *objects;
  68 static struct object_stat *obj_stat;
  69 static struct ofs_delta_entry *ofs_deltas;
  70 static struct ref_delta_entry *ref_deltas;
  71 static struct thread_local nothread_data;
  72 static int nr_objects;
  73 static int nr_ofs_deltas;
  74 static int nr_ref_deltas;
  75 static int ref_deltas_alloc;
  76 static int nr_resolved_deltas;
  77 static int nr_threads;
  78
  79 static int from_stdin;
  80 static int strict;
  81 static int do_fsck_object;
  82 static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
  83 static int verbose;
  84 static int show_resolving_progress;
  85 static int show_stat;
  86 static int check_self_contained_and_connected;
  87
  88 static struct progress *progress;
  89
  90 /* We always read in 4kB chunks. */
  91 static unsigned char input_buffer[4096];
  92 static unsigned int input_offset, input_len;
  93 static off_t consumed_bytes;
  94 static off_t max_input_size;
  95 static unsigned deepest_delta;
  96 static git_hash_ctx input_ctx;
  97 static uint32_t input_crc32;
  98 static int input_fd, output_fd;
  99 static const char *curr_pack;
 100
 101 static struct thread_local *thread_data;
 102 static int nr_dispatched;
 103 static int threads_active;
 104
 105 static pthread_mutex_t read_mutex;
 106 #define read_lock()             lock_mutex(&read_mutex)
 107 #define read_unlock()           unlock_mutex(&read_mutex)
 108
 109 static pthread_mutex_t counter_mutex;
 110 #define counter_lock()          lock_mutex(&counter_mutex)
 111 #define counter_unlock()        unlock_mutex(&counter_mutex)
 112
 113 static pthread_mutex_t work_mutex;
 114 #define work_lock()             lock_mutex(&work_mutex)
 115 #define work_unlock()           unlock_mutex(&work_mutex)
 116
 117 static pthread_mutex_t deepest_delta_mutex;
 118 #define deepest_delta_lock()    lock_mutex(&deepest_delta_mutex)
 119 #define deepest_delta_unlock()  unlock_mutex(&deepest_delta_mutex)
 120
 121 static pthread_mutex_t type_cas_mutex;
 122 #define type_cas_lock()         lock_mutex(&type_cas_mutex)
 123 #define type_cas_unlock()       unlock_mutex(&type_cas_mutex)
 124
 125 static pthread_key_t key;
 126
 127 static inline void lock_mutex(pthread_mutex_t *mutex)
 128 {
 129         if (threads_active)
 130                 pthread_mutex_lock(mutex);
 131 }
 132
 133 static inline void unlock_mutex(pthread_mutex_t *mutex)
 134 {
 135         if (threads_active)
 136                 pthread_mutex_unlock(mutex);
 137 }
 138
 139 /*
 140  * Mutex and conditional variable can't be statically-initialized on Windows.
 141  */
 142 static void init_thread(void)
 143 {
 144         int i;
 145         init_recursive_mutex(&read_mutex);
 146         pthread_mutex_init(&counter_mutex, NULL);
 147         pthread_mutex_init(&work_mutex, NULL);
 148         pthread_mutex_init(&type_cas_mutex, NULL);
 149         if (show_stat)
 150                 pthread_mutex_init(&deepest_delta_mutex, NULL);
 151         pthread_key_create(&key, NULL);
 152         thread_data = xcalloc(nr_threads, sizeof(*thread_data));
 153         for (i = 0; i < nr_threads; i++) {
 154                 thread_data[i].pack_fd = open(curr_pack, O_RDONLY);
 155                 if (thread_data[i].pack_fd == -1)
 156                         die_errno(_("unable to open %s"), curr_pack);
 157         }
 158
 159         threads_active = 1;
 160 }
 161
 162 static void cleanup_thread(void)
 163 {
 164         int i;
 165         if (!threads_active)
 166                 return;
 167         threads_active = 0;
 168         pthread_mutex_destroy(&read_mutex);
 169         pthread_mutex_destroy(&counter_mutex);
 170         pthread_mutex_destroy(&work_mutex);
 171         pthread_mutex_destroy(&type_cas_mutex);
 172         if (show_stat)
 173                 pthread_mutex_destroy(&deepest_delta_mutex);
 174         for (i = 0; i < nr_threads; i++)
 175                 close(thread_data[i].pack_fd);
 176         pthread_key_delete(key);
 177         free(thread_data);
 178 }
 179
 180 static int mark_link(struct object *obj, int type, void *data, struct fsck_options *options)
 181 {
 182         if (!obj)
 183                 return -1;
 184
 185         if (type != OBJ_ANY && obj->type != type)
 186                 die(_("object type mismatch at %s"), oid_to_hex(&obj->oid));
 187
 188         obj->flags |= FLAG_LINK;
 189         return 0;
 190 }
 191
 192 /* The content of each linked object must have been checked
 193    or it must be already present in the object database */
 194 static unsigned check_object(struct object *obj)
 195 {
 196         if (!obj)
 197                 return 0;
 198
 199         if (!(obj->flags & FLAG_LINK))
 200                 return 0;
 201
 202         if (!(obj->flags & FLAG_CHECKED)) {
 203                 unsigned long size;
 204                 int type = oid_object_info(the_repository, &obj->oid, &size);
 205                 if (type <= 0)
 206                         die(_("did not receive expected object %s"),
 207                               oid_to_hex(&obj->oid));
 208                 if (type != obj->type)
 209                         die(_("object %s: expected type %s, found %s"),
 210                             oid_to_hex(&obj->oid),
 211                             type_name(obj->type), type_name(type));
 212                 obj->flags |= FLAG_CHECKED;
 213                 return 1;
 214         }
 215
 216         return 0;
 217 }
 218
 219 static unsigned check_objects(void)
 220 {
 221         unsigned i, max, foreign_nr = 0;
 222
 223         max = get_max_object_index();
 224
 225         if (verbose)
 226                 progress = start_delayed_progress(_("Checking objects"), max);
 227
 228         for (i = 0; i < max; i++) {
 229                 foreign_nr += check_object(get_indexed_object(i));
 230                 display_progress(progress, i + 1);
 231         }
 232
 233         stop_progress(&progress);
 234         return foreign_nr;
 235 }
 236
 237
 238 /* Discard current buffer used content. */
 239 static void flush(void)
 240 {
 241         if (input_offset) {
 242                 if (output_fd >= 0)
 243                         write_or_die(output_fd, input_buffer, input_offset);
 244                 the_hash_algo->update_fn(&input_ctx, input_buffer, input_offset);
 245                 memmove(input_buffer, input_buffer + input_offset, input_len);
 246                 input_offset = 0;
 247         }
 248 }
 249
 250 /*
 251  * Make sure at least "min" bytes are available in the buffer, and
 252  * return the pointer to the buffer.
 253  */
 254 static void *fill(int min)
 255 {
 256         if (min <= input_len)
 257                 return input_buffer + input_offset;
 258         if (min > sizeof(input_buffer))
 259                 die(Q_("cannot fill %d byte",
 260                        "cannot fill %d bytes",
 261                        min),
 262                     min);
 263         flush();
 264         do {
 265                 ssize_t ret = xread(input_fd, input_buffer + input_len,
 266                                 sizeof(input_buffer) - input_len);
 267                 if (ret <= 0) {
 268                         if (!ret)
 269                                 die(_("early EOF"));
 270                         die_errno(_("read error on input"));
 271                 }
 272                 input_len += ret;
 273                 if (from_stdin)
 274                         display_throughput(progress, consumed_bytes + input_len);
 275         } while (input_len < min);
 276         return input_buffer;
 277 }
 278
 279 static void use(int bytes)
 280 {
 281         if (bytes > input_len)
 282                 die(_("used more bytes than were available"));
 283         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 284         input_len -= bytes;
 285         input_offset += bytes;
 286
 287         /* make sure off_t is sufficiently large not to wrap */
 288         if (signed_add_overflows(consumed_bytes, bytes))
 289                 die(_("pack too large for current definition of off_t"));
 290         consumed_bytes += bytes;
 291         if (max_input_size && consumed_bytes > max_input_size)
 292                 die(_("pack exceeds maximum allowed size"));
 293 }
 294
 295 static const char *open_pack_file(const char *pack_name)
 296 {
 297         if (from_stdin) {
 298                 input_fd = 0;
 299                 if (!pack_name) {
 300                         struct strbuf tmp_file = STRBUF_INIT;
 301                         output_fd = odb_mkstemp(&tmp_file,
 302                                                 "pack/tmp_pack_XXXXXX");
 303                         pack_name = strbuf_detach(&tmp_file, NULL);
 304                 } else {
 305                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 306                         if (output_fd < 0)
 307                                 die_errno(_("unable to create '%s'"), pack_name);
 308                 }
 309                 nothread_data.pack_fd = output_fd;
 310         } else {
 311                 input_fd = open(pack_name, O_RDONLY);
 312                 if (input_fd < 0)
 313                         die_errno(_("cannot open packfile '%s'"), pack_name);
 314                 output_fd = -1;
 315                 nothread_data.pack_fd = input_fd;
 316         }
 317         the_hash_algo->init_fn(&input_ctx);
 318         return pack_name;
 319 }
 320
 321 static void parse_pack_header(void)
 322 {
 323         struct pack_header *hdr = fill(sizeof(struct pack_header));
 324
 325         /* Header consistency check */
 326         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 327                 die(_("pack signature mismatch"));
 328         if (!pack_version_ok(hdr->hdr_version))
 329                 die(_("pack version %"PRIu32" unsupported"),
 330                         ntohl(hdr->hdr_version));
 331
 332         nr_objects = ntohl(hdr->hdr_entries);
 333         use(sizeof(struct pack_header));
 334 }
 335
 336 static NORETURN void bad_object(off_t offset, const char *format,
 337                        ...) __attribute__((format (printf, 2, 3)));
 338
 339 static NORETURN void bad_object(off_t offset, const char *format, ...)
 340 {
 341         va_list params;
 342         char buf[1024];
 343
 344         va_start(params, format);
 345         vsnprintf(buf, sizeof(buf), format, params);
 346         va_end(params);
 347         die(_("pack has bad object at offset %"PRIuMAX": %s"),
 348             (uintmax_t)offset, buf);
 349 }
 350
 351 static inline struct thread_local *get_thread_data(void)
 352 {
 353         if (HAVE_THREADS) {
 354                 if (threads_active)
 355                         return pthread_getspecific(key);
 356                 assert(!threads_active &&
 357                        "This should only be reached when all threads are gone");
 358         }
 359         return &nothread_data;
 360 }
 361
 362 static void set_thread_data(struct thread_local *data)
 363 {
 364         if (threads_active)
 365                 pthread_setspecific(key, data);
 366 }
 367
 368 static void free_base_data(struct base_data *c)
 369 {
 370         if (c->data) {
 371                 FREE_AND_NULL(c->data);
 372                 get_thread_data()->base_cache_used -= c->size;
 373         }
 374 }
 375
 376 static void prune_base_data(struct base_data *youngest_child)
 377 {
 378         struct base_data *b;
 379         struct thread_local *data = get_thread_data();
 380         struct base_data **ancestry = NULL;
 381         size_t nr = 0, alloc = 0;
 382         ssize_t i;
 383
 384         if (data->base_cache_used <= delta_base_cache_limit)
 385                 return;
 386
 387         /*
 388          * Free all ancestors of youngest_child until we have enough space,
 389          * starting with the oldest. (We cannot free youngest_child itself.)
 390          */
 391         for (b = youngest_child->base; b != NULL; b = b->base) {
 392                 ALLOC_GROW(ancestry, nr + 1, alloc);
 393                 ancestry[nr++] = b;
 394         }
 395         for (i = nr - 1;
 396              i >= 0 && data->base_cache_used > delta_base_cache_limit;
 397              i--) {
 398                 if (ancestry[i]->data)
 399                         free_base_data(ancestry[i]);
 400         }
 401         free(ancestry);
 402 }
 403
 404 static int is_delta_type(enum object_type type)
 405 {
 406         return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
 407 }
 408
 409 static void *unpack_entry_data(off_t offset, unsigned long size,
 410                                enum object_type type, struct object_id *oid)
 411 {
 412         static char fixed_buf[8192];
 413         int status;
 414         git_zstream stream;
 415         void *buf;
 416         git_hash_ctx c;
 417         char hdr[32];
 418         int hdrlen;
 419
 420         if (!is_delta_type(type)) {
 421                 hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX,
 422                                    type_name(type),(uintmax_t)size) + 1;
 423                 the_hash_algo->init_fn(&c);
 424                 the_hash_algo->update_fn(&c, hdr, hdrlen);
 425         } else
 426                 oid = NULL;
 427         if (type == OBJ_BLOB && size > big_file_threshold)
 428                 buf = fixed_buf;
 429         else
 430                 buf = xmallocz(size);
 431
 432         memset(&stream, 0, sizeof(stream));
 433         git_inflate_init(&stream);
 434         stream.next_out = buf;
 435         stream.avail_out = buf == fixed_buf ? sizeof(fixed_buf) : size;
 436
 437         do {
 438                 unsigned char *last_out = stream.next_out;
 439                 stream.next_in = fill(1);
 440                 stream.avail_in = input_len;
 441                 status = git_inflate(&stream, 0);
 442                 use(input_len - stream.avail_in);
 443                 if (oid)
 444                         the_hash_algo->update_fn(&c, last_out, stream.next_out - last_out);
 445                 if (buf == fixed_buf) {
 446                         stream.next_out = buf;
 447                         stream.avail_out = sizeof(fixed_buf);
 448                 }
 449         } while (status == Z_OK);
 450         if (stream.total_out != size || status != Z_STREAM_END)
 451                 bad_object(offset, _("inflate returned %d"), status);
 452         git_inflate_end(&stream);
 453         if (oid)
 454                 the_hash_algo->final_fn(oid->hash, &c);
 455         return buf == fixed_buf ? NULL : buf;
 456 }
 457
 458 static void *unpack_raw_entry(struct object_entry *obj,
 459                               off_t *ofs_offset,
 460                               struct object_id *ref_oid,
 461                               struct object_id *oid)
 462 {
 463         unsigned char *p;
 464         unsigned long size, c;
 465         off_t base_offset;
 466         unsigned shift;
 467         void *data;
 468
 469         obj->idx.offset = consumed_bytes;
 470         input_crc32 = crc32(0, NULL, 0);
 471
 472         p = fill(1);
 473         c = *p;
 474         use(1);
 475         obj->type = (c >> 4) & 7;
 476         size = (c & 15);
 477         shift = 4;
 478         while (c & 0x80) {
 479                 p = fill(1);
 480                 c = *p;
 481                 use(1);
 482                 size += (c & 0x7f) << shift;
 483                 shift += 7;
 484         }
 485         obj->size = size;
 486
 487         switch (obj->type) {
 488         case OBJ_REF_DELTA:
 489                 hashcpy(ref_oid->hash, fill(the_hash_algo->rawsz));
 490                 use(the_hash_algo->rawsz);
 491                 break;
 492         case OBJ_OFS_DELTA:
 493                 p = fill(1);
 494                 c = *p;
 495                 use(1);
 496                 base_offset = c & 127;
 497                 while (c & 128) {
 498                         base_offset += 1;
 499                         if (!base_offset || MSB(base_offset, 7))
 500                                 bad_object(obj->idx.offset, _("offset value overflow for delta base object"));
 501                         p = fill(1);
 502                         c = *p;
 503                         use(1);
 504                         base_offset = (base_offset << 7) + (c & 127);
 505                 }
 506                 *ofs_offset = obj->idx.offset - base_offset;
 507                 if (*ofs_offset <= 0 || *ofs_offset >= obj->idx.offset)
 508                         bad_object(obj->idx.offset, _("delta base offset is out of bound"));
 509                 break;
 510         case OBJ_COMMIT:
 511         case OBJ_TREE:
 512         case OBJ_BLOB:
 513         case OBJ_TAG:
 514                 break;
 515         default:
 516                 bad_object(obj->idx.offset, _("unknown object type %d"), obj->type);
 517         }
 518         obj->hdr_size = consumed_bytes - obj->idx.offset;
 519
 520         data = unpack_entry_data(obj->idx.offset, obj->size, obj->type, oid);
 521         obj->idx.crc32 = input_crc32;
 522         return data;
 523 }
 524
 525 static void *unpack_data(struct object_entry *obj,
 526                          int (*consume)(const unsigned char *, unsigned long, void *),
 527                          void *cb_data)
 528 {
 529         off_t from = obj[0].idx.offset + obj[0].hdr_size;
 530         off_t len = obj[1].idx.offset - from;
 531         unsigned char *data, *inbuf;
 532         git_zstream stream;
 533         int status;
 534
 535         data = xmallocz(consume ? 64*1024 : obj->size);
 536         inbuf = xmalloc((len < 64*1024) ? (int)len : 64*1024);
 537
 538         memset(&stream, 0, sizeof(stream));
 539         git_inflate_init(&stream);
 540         stream.next_out = data;
 541         stream.avail_out = consume ? 64*1024 : obj->size;
 542
 543         do {
 544                 ssize_t n = (len < 64*1024) ? (ssize_t)len : 64*1024;
 545                 n = xpread(get_thread_data()->pack_fd, inbuf, n, from);
 546                 if (n < 0)
 547                         die_errno(_("cannot pread pack file"));
 548                 if (!n)
 549                         die(Q_("premature end of pack file, %"PRIuMAX" byte missing",
 550                                "premature end of pack file, %"PRIuMAX" bytes missing",
 551                                (unsigned int)len),
 552                             (uintmax_t)len);
 553                 from += n;
 554                 len -= n;
 555                 stream.next_in = inbuf;
 556                 stream.avail_in = n;
 557                 if (!consume)
 558                         status = git_inflate(&stream, 0);
 559                 else {
 560                         do {
 561                                 status = git_inflate(&stream, 0);
 562                                 if (consume(data, stream.next_out - data, cb_data)) {
 563                                         free(inbuf);
 564                                         free(data);
 565                                         return NULL;
 566                                 }
 567                                 stream.next_out = data;
 568                                 stream.avail_out = 64*1024;
 569                         } while (status == Z_OK && stream.avail_in);
 570                 }
 571         } while (len && status == Z_OK && !stream.avail_in);
 572
 573         /* This has been inflated OK when first encountered, so... */
 574         if (status != Z_STREAM_END || stream.total_out != obj->size)
 575                 die(_("serious inflate inconsistency"));
 576
 577         git_inflate_end(&stream);
 578         free(inbuf);
 579         if (consume) {
 580                 FREE_AND_NULL(data);
 581         }
 582         return data;
 583 }
 584
 585 static void *get_data_from_pack(struct object_entry *obj)
 586 {
 587         return unpack_data(obj, NULL, NULL);
 588 }
 589
 590 static int compare_ofs_delta_bases(off_t offset1, off_t offset2,
 591                                    enum object_type type1,
 592                                    enum object_type type2)
 593 {
 594         int cmp = type1 - type2;
 595         if (cmp)
 596                 return cmp;
 597         return offset1 < offset2 ? -1 :
 598                offset1 > offset2 ?  1 :
 599                0;
 600 }
 601
 602 static int find_ofs_delta(const off_t offset)
 603 {
 604         int first = 0, last = nr_ofs_deltas;
 605
 606         while (first < last) {
 607                 int next = first + (last - first) / 2;
 608                 struct ofs_delta_entry *delta = &ofs_deltas[next];
 609                 int cmp;
 610
 611                 cmp = compare_ofs_delta_bases(offset, delta->offset,
 612                                               OBJ_OFS_DELTA,
 613                                               objects[delta->obj_no].type);
 614                 if (!cmp)
 615                         return next;
 616                 if (cmp < 0) {
 617                         last = next;
 618                         continue;
 619                 }
 620                 first = next+1;
 621         }
 622         return -first-1;
 623 }
 624
 625 static void find_ofs_delta_children(off_t offset,
 626                                     int *first_index, int *last_index)
 627 {
 628         int first = find_ofs_delta(offset);
 629         int last = first;
 630         int end = nr_ofs_deltas - 1;
 631
 632         if (first < 0) {
 633                 *first_index = 0;
 634                 *last_index = -1;
 635                 return;
 636         }
 637         while (first > 0 && ofs_deltas[first - 1].offset == offset)
 638                 --first;
 639         while (last < end && ofs_deltas[last + 1].offset == offset)
 640                 ++last;
 641         *first_index = first;
 642         *last_index = last;
 643 }
 644
 645 static int compare_ref_delta_bases(const struct object_id *oid1,
 646                                    const struct object_id *oid2,
 647                                    enum object_type type1,
 648                                    enum object_type type2)
 649 {
 650         int cmp = type1 - type2;
 651         if (cmp)
 652                 return cmp;
 653         return oidcmp(oid1, oid2);
 654 }
 655
 656 static int find_ref_delta(const struct object_id *oid)
 657 {
 658         int first = 0, last = nr_ref_deltas;
 659
 660         while (first < last) {
 661                 int next = first + (last - first) / 2;
 662                 struct ref_delta_entry *delta = &ref_deltas[next];
 663                 int cmp;
 664
 665                 cmp = compare_ref_delta_bases(oid, &delta->oid,
 666                                               OBJ_REF_DELTA,
 667                                               objects[delta->obj_no].type);
 668                 if (!cmp)
 669                         return next;
 670                 if (cmp < 0) {
 671                         last = next;
 672                         continue;
 673                 }
 674                 first = next+1;
 675         }
 676         return -first-1;
 677 }
 678
 679 static void find_ref_delta_children(const struct object_id *oid,
 680                                     int *first_index, int *last_index)
 681 {
 682         int first = find_ref_delta(oid);
 683         int last = first;
 684         int end = nr_ref_deltas - 1;
 685
 686         if (first < 0) {
 687                 *first_index = 0;
 688                 *last_index = -1;
 689                 return;
 690         }
 691         while (first > 0 && oideq(&ref_deltas[first - 1].oid, oid))
 692                 --first;
 693         while (last < end && oideq(&ref_deltas[last + 1].oid, oid))
 694                 ++last;
 695         *first_index = first;
 696         *last_index = last;
 697 }
 698
 699 struct compare_data {
 700         struct object_entry *entry;
 701         struct git_istream *st;
 702         unsigned char *buf;
 703         unsigned long buf_size;
 704 };
 705
 706 static int compare_objects(const unsigned char *buf, unsigned long size,
 707                            void *cb_data)
 708 {
 709         struct compare_data *data = cb_data;
 710
 711         if (data->buf_size < size) {
 712                 free(data->buf);
 713                 data->buf = xmalloc(size);
 714                 data->buf_size = size;
 715         }
 716
 717         while (size) {
 718                 ssize_t len = read_istream(data->st, data->buf, size);
 719                 if (len == 0)
 720                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 721                             oid_to_hex(&data->entry->idx.oid));
 722                 if (len < 0)
 723                         die(_("unable to read %s"),
 724                             oid_to_hex(&data->entry->idx.oid));
 725                 if (memcmp(buf, data->buf, len))
 726                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 727                             oid_to_hex(&data->entry->idx.oid));
 728                 size -= len;
 729                 buf += len;
 730         }
 731         return 0;
 732 }
 733
 734 static int check_collison(struct object_entry *entry)
 735 {
 736         struct compare_data data;
 737         enum object_type type;
 738         unsigned long size;
 739
 740         if (entry->size <= big_file_threshold || entry->type != OBJ_BLOB)
 741                 return -1;
 742
 743         memset(&data, 0, sizeof(data));
 744         data.entry = entry;
 745         data.st = open_istream(the_repository, &entry->idx.oid, &type, &size,
 746                                NULL);
 747         if (!data.st)
 748                 return -1;
 749         if (size != entry->size || type != entry->type)
 750                 die(_("SHA1 COLLISION FOUND WITH %s !"),
 751                     oid_to_hex(&entry->idx.oid));
 752         unpack_data(entry, compare_objects, &data);
 753         close_istream(data.st);
 754         free(data.buf);
 755         return 0;
 756 }
 757
 758 static void sha1_object(const void *data, struct object_entry *obj_entry,
 759                         unsigned long size, enum object_type type,
 760                         const struct object_id *oid)
 761 {
 762         void *new_data = NULL;
 763         int collision_test_needed = 0;
 764
 765         assert(data || obj_entry);
 766
 767         if (startup_info->have_repository) {
 768                 read_lock();
 769                 collision_test_needed =
 770                         has_object_file_with_flags(oid, OBJECT_INFO_QUICK);
 771                 read_unlock();
 772         }
 773
 774         if (collision_test_needed && !data) {
 775                 read_lock();
 776                 if (!check_collison(obj_entry))
 777                         collision_test_needed = 0;
 778                 read_unlock();
 779         }
 780         if (collision_test_needed) {
 781                 void *has_data;
 782                 enum object_type has_type;
 783                 unsigned long has_size;
 784                 read_lock();
 785                 has_type = oid_object_info(the_repository, oid, &has_size);
 786                 if (has_type < 0)
 787                         die(_("cannot read existing object info %s"), oid_to_hex(oid));
 788                 if (has_type != type || has_size != size)
 789                         die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
 790                 has_data = read_object_file(oid, &has_type, &has_size);
 791                 read_unlock();
 792                 if (!data)
 793                         data = new_data = get_data_from_pack(obj_entry);
 794                 if (!has_data)
 795                         die(_("cannot read existing object %s"), oid_to_hex(oid));
 796                 if (size != has_size || type != has_type ||
 797                     memcmp(data, has_data, size) != 0)
 798                         die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
 799                 free(has_data);
 800         }
 801
 802         if (strict || do_fsck_object) {
 803                 read_lock();
 804                 if (type == OBJ_BLOB) {
 805                         struct blob *blob = lookup_blob(the_repository, oid);
 806                         if (blob)
 807                                 blob->object.flags |= FLAG_CHECKED;
 808                         else
 809                                 die(_("invalid blob object %s"), oid_to_hex(oid));
 810                         if (do_fsck_object &&
 811                             fsck_object(&blob->object, (void *)data, size, &fsck_options))
 812                                 die(_("fsck error in packed object"));
 813                 } else {
 814                         struct object *obj;
 815                         int eaten;
 816                         void *buf = (void *) data;
 817
 818                         assert(data && "data can only be NULL for large _blobs_");
 819
 820                         /*
 821                          * we do not need to free the memory here, as the
 822                          * buf is deleted by the caller.
 823                          */
 824                         obj = parse_object_buffer(the_repository, oid, type,
 825                                                   size, buf,
 826                                                   &eaten);
 827                         if (!obj)
 828                                 die(_("invalid %s"), type_name(type));
 829                         if (do_fsck_object &&
 830                             fsck_object(obj, buf, size, &fsck_options))
 831                                 die(_("fsck error in packed object"));
 832                         if (strict && fsck_walk(obj, NULL, &fsck_options))
 833                                 die(_("Not all child objects of %s are reachable"), oid_to_hex(&obj->oid));
 834
 835                         if (obj->type == OBJ_TREE) {
 836                                 struct tree *item = (struct tree *) obj;
 837                                 item->buffer = NULL;
 838                                 obj->parsed = 0;
 839                         }
 840                         if (obj->type == OBJ_COMMIT) {
 841                                 struct commit *commit = (struct commit *) obj;
 842                                 if (detach_commit_buffer(commit, NULL) != data)
 843                                         BUG("parse_object_buffer transmogrified our buffer");
 844                         }
 845                         obj->flags |= FLAG_CHECKED;
 846                 }
 847                 read_unlock();
 848         }
 849
 850         free(new_data);
 851 }
 852
 853 /*
 854  * This function is part of find_unresolved_deltas(). There are two
 855  * walkers going in the opposite ways.
 856  *
 857  * The first one in find_unresolved_deltas() traverses down from
 858  * parent node to children, deflating nodes along the way. However,
 859  * memory for deflated nodes is limited by delta_base_cache_limit, so
 860  * at some point parent node's deflated content may be freed.
 861  *
 862  * The second walker is this function, which goes from current node up
 863  * to top parent if necessary to deflate the node. In normal
 864  * situation, its parent node would be already deflated, so it just
 865  * needs to apply delta.
 866  *
 867  * In the worst case scenario, parent node is no longer deflated because
 868  * we're running out of delta_base_cache_limit; we need to re-deflate
 869  * parents, possibly up to the top base.
 870  *
 871  * All deflated objects here are subject to be freed if we exceed
 872  * delta_base_cache_limit, just like in find_unresolved_deltas(), we
 873  * just need to make sure the last node is not freed.
 874  */
 875 static void *get_base_data(struct base_data *c)
 876 {
 877         if (!c->data) {
 878                 struct object_entry *obj = c->obj;
 879                 struct base_data **delta = NULL;
 880                 int delta_nr = 0, delta_alloc = 0;
 881
 882                 while (is_delta_type(c->obj->type) && !c->data) {
 883                         ALLOC_GROW(delta, delta_nr + 1, delta_alloc);
 884                         delta[delta_nr++] = c;
 885                         c = c->base;
 886                 }
 887                 if (!delta_nr) {
 888                         c->data = get_data_from_pack(obj);
 889                         c->size = obj->size;
 890                         get_thread_data()->base_cache_used += c->size;
 891                         prune_base_data(c);
 892                 }
 893                 for (; delta_nr > 0; delta_nr--) {
 894                         void *base, *raw;
 895                         c = delta[delta_nr - 1];
 896                         obj = c->obj;
 897                         base = get_base_data(c->base);
 898                         raw = get_data_from_pack(obj);
 899                         c->data = patch_delta(
 900                                 base, c->base->size,
 901                                 raw, obj->size,
 902                                 &c->size);
 903                         free(raw);
 904                         if (!c->data)
 905                                 bad_object(obj->idx.offset, _("failed to apply delta"));
 906                         get_thread_data()->base_cache_used += c->size;
 907                         prune_base_data(c);
 908                 }
 909                 free(delta);
 910         }
 911         return c->data;
 912 }
 913
 914 static struct base_data *make_base(struct object_entry *obj,
 915                                    struct base_data *parent)
 916 {
 917         struct base_data *base = xcalloc(1, sizeof(struct base_data));
 918         base->base = parent;
 919         base->obj = obj;
 920         find_ref_delta_children(&obj->idx.oid,
 921                                 &base->ref_first, &base->ref_last);
 922         find_ofs_delta_children(obj->idx.offset,
 923                                 &base->ofs_first, &base->ofs_last);
 924         return base;
 925 }
 926
 927 static struct base_data *resolve_delta(struct object_entry *delta_obj,
 928                                        struct base_data *base)
 929 {
 930         void *base_data, *delta_data, *result_data;
 931         struct base_data *result;
 932         unsigned long result_size;
 933
 934         if (show_stat) {
 935                 int i = delta_obj - objects;
 936                 int j = base->obj - objects;
 937                 obj_stat[i].delta_depth = obj_stat[j].delta_depth + 1;
 938                 deepest_delta_lock();
 939                 if (deepest_delta < obj_stat[i].delta_depth)
 940                         deepest_delta = obj_stat[i].delta_depth;
 941                 deepest_delta_unlock();
 942                 obj_stat[i].base_object_no = j;
 943         }
 944         delta_data = get_data_from_pack(delta_obj);
 945         base_data = get_base_data(base);
 946         result_data = patch_delta(base_data, base->size,
 947                                   delta_data, delta_obj->size, &result_size);
 948         free(delta_data);
 949         if (!result_data)
 950                 bad_object(delta_obj->idx.offset, _("failed to apply delta"));
 951         hash_object_file(the_hash_algo, result_data, result_size,
 952                          type_name(delta_obj->real_type), &delta_obj->idx.oid);
 953         sha1_object(result_data, NULL, result_size, delta_obj->real_type,
 954                     &delta_obj->idx.oid);
 955
 956         result = make_base(delta_obj, base);
 957         if (result->ref_last == -1 && result->ofs_last == -1) {
 958                 free(result_data);
 959         } else {
 960                 result->data = result_data;
 961                 result->size = result_size;
 962                 get_thread_data()->base_cache_used += result->size;
 963                 prune_base_data(result);
 964         }
 965
 966         counter_lock();
 967         nr_resolved_deltas++;
 968         counter_unlock();
 969
 970         return result;
 971 }
 972
 973 /*
 974  * Standard boolean compare-and-swap: atomically check whether "*type" is
 975  * "want"; if so, swap in "set" and return true. Otherwise, leave it untouched
 976  * and return false.
 977  */
 978 static int compare_and_swap_type(signed char *type,
 979                                  enum object_type want,
 980                                  enum object_type set)
 981 {
 982         enum object_type old;
 983
 984         type_cas_lock();
 985         old = *type;
 986         if (old == want)
 987                 *type = set;
 988         type_cas_unlock();
 989
 990         return old == want;
 991 }
 992
 993 static struct base_data *find_unresolved_deltas_1(struct base_data *base,
 994                                                   struct base_data *prev_base)
 995 {
 996         if (base->ref_first <= base->ref_last) {
 997                 struct object_entry *child = objects + ref_deltas[base->ref_first].obj_no;
 998                 struct base_data *result;
 999
1000                 if (!compare_and_swap_type(&child->real_type, OBJ_REF_DELTA,
1001                                            base->obj->real_type))
1002                         die("REF_DELTA at offset %"PRIuMAX" already resolved (duplicate base %s?)",
1003                             (uintmax_t)child->idx.offset,
1004                             oid_to_hex(&base->obj->idx.oid));
1005
1006                 result = resolve_delta(child, base);
1007                 if (base->ref_first == base->ref_last && base->ofs_last == -1)
1008                         free_base_data(base);
1009
1010                 base->ref_first++;
1011                 return result;
1012         }
1013
1014         if (base->ofs_first <= base->ofs_last) {
1015                 struct object_entry *child = objects + ofs_deltas[base->ofs_first].obj_no;
1016                 struct base_data *result;
1017
1018                 assert(child->real_type == OBJ_OFS_DELTA);
1019                 child->real_type = base->obj->real_type;
1020                 result = resolve_delta(child, base);
1021                 if (base->ofs_first == base->ofs_last)
1022                         free_base_data(base);
1023
1024                 base->ofs_first++;
1025                 return result;
1026         }
1027
1028         free_base_data(base);
1029         return NULL;
1030 }
1031
1032 static void find_unresolved_deltas(struct base_data *base)
1033 {
1034         struct base_data *new_base, *prev_base = NULL;
1035         for (;;) {
1036                 new_base = find_unresolved_deltas_1(base, prev_base);
1037
1038                 if (new_base) {
1039                         prev_base = base;
1040                         base = new_base;
1041                 } else {
1042                         free(base);
1043                         base = prev_base;
1044                         if (!base)
1045                                 return;
1046                         prev_base = base->base;
1047                 }
1048         }
1049 }
1050
1051 static int compare_ofs_delta_entry(const void *a, const void *b)
1052 {
1053         const struct ofs_delta_entry *delta_a = a;
1054         const struct ofs_delta_entry *delta_b = b;
1055
1056         return delta_a->offset < delta_b->offset ? -1 :
1057                delta_a->offset > delta_b->offset ?  1 :
1058                0;
1059 }
1060
1061 static int compare_ref_delta_entry(const void *a, const void *b)
1062 {
1063         const struct ref_delta_entry *delta_a = a;
1064         const struct ref_delta_entry *delta_b = b;
1065
1066         return oidcmp(&delta_a->oid, &delta_b->oid);
1067 }
1068
1069 static void resolve_base(struct object_entry *obj)
1070 {
1071         struct base_data *base_obj = make_base(obj, NULL);
1072
1073         find_unresolved_deltas(base_obj);
1074 }
1075
1076 static void *threaded_second_pass(void *data)
1077 {
1078         set_thread_data(data);
1079         for (;;) {
1080                 int i;
1081                 counter_lock();
1082                 display_progress(progress, nr_resolved_deltas);
1083                 counter_unlock();
1084                 work_lock();
1085                 while (nr_dispatched < nr_objects &&
1086                        is_delta_type(objects[nr_dispatched].type))
1087                         nr_dispatched++;
1088                 if (nr_dispatched >= nr_objects) {
1089                         work_unlock();
1090                         break;
1091                 }
1092                 i = nr_dispatched++;
1093                 work_unlock();
1094
1095                 resolve_base(&objects[i]);
1096         }
1097         return NULL;
1098 }
1099
1100 /*
1101  * First pass:
1102  * - find locations of all objects;
1103  * - calculate SHA1 of all non-delta objects;
1104  * - remember base (SHA1 or offset) for all deltas.
1105  */
1106 static void parse_pack_objects(unsigned char *hash)
1107 {
1108         int i, nr_delays = 0;
1109         struct ofs_delta_entry *ofs_delta = ofs_deltas;
1110         struct object_id ref_delta_oid;
1111         struct stat st;
1112
1113         if (verbose)
1114                 progress = start_progress(
1115                                 from_stdin ? _("Receiving objects") : _("Indexing objects"),
1116                                 nr_objects);
1117         for (i = 0; i < nr_objects; i++) {
1118                 struct object_entry *obj = &objects[i];
1119                 void *data = unpack_raw_entry(obj, &ofs_delta->offset,
1120                                               &ref_delta_oid,
1121                                               &obj->idx.oid);
1122                 obj->real_type = obj->type;
1123                 if (obj->type == OBJ_OFS_DELTA) {
1124                         nr_ofs_deltas++;
1125                         ofs_delta->obj_no = i;
1126                         ofs_delta++;
1127                 } else if (obj->type == OBJ_REF_DELTA) {
1128                         ALLOC_GROW(ref_deltas, nr_ref_deltas + 1, ref_deltas_alloc);
1129                         oidcpy(&ref_deltas[nr_ref_deltas].oid, &ref_delta_oid);
1130                         ref_deltas[nr_ref_deltas].obj_no = i;
1131                         nr_ref_deltas++;
1132                 } else if (!data) {
1133                         /* large blobs, check later */
1134                         obj->real_type = OBJ_BAD;
1135                         nr_delays++;
1136                 } else
1137                         sha1_object(data, NULL, obj->size, obj->type,
1138                                     &obj->idx.oid);
1139                 free(data);
1140                 display_progress(progress, i+1);
1141         }
1142         objects[i].idx.offset = consumed_bytes;
1143         stop_progress(&progress);
1144
1145         /* Check pack integrity */
1146         flush();
1147         the_hash_algo->final_fn(hash, &input_ctx);
1148         if (!hasheq(fill(the_hash_algo->rawsz), hash))
1149                 die(_("pack is corrupted (SHA1 mismatch)"));
1150         use(the_hash_algo->rawsz);
1151
1152         /* If input_fd is a file, we should have reached its end now. */
1153         if (fstat(input_fd, &st))
1154                 die_errno(_("cannot fstat packfile"));
1155         if (S_ISREG(st.st_mode) &&
1156                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
1157                 die(_("pack has junk at the end"));
1158
1159         for (i = 0; i < nr_objects; i++) {
1160                 struct object_entry *obj = &objects[i];
1161                 if (obj->real_type != OBJ_BAD)
1162                         continue;
1163                 obj->real_type = obj->type;
1164                 sha1_object(NULL, obj, obj->size, obj->type,
1165                             &obj->idx.oid);
1166                 nr_delays--;
1167         }
1168         if (nr_delays)
1169                 die(_("confusion beyond insanity in parse_pack_objects()"));
1170 }
1171
1172 /*
1173  * Second pass:
1174  * - for all non-delta objects, look if it is used as a base for
1175  *   deltas;
1176  * - if used as a base, uncompress the object and apply all deltas,
1177  *   recursively checking if the resulting object is used as a base
1178  *   for some more deltas.
1179  */
1180 static void resolve_deltas(void)
1181 {
1182         int i;
1183
1184         if (!nr_ofs_deltas && !nr_ref_deltas)
1185                 return;
1186
1187         /* Sort deltas by base SHA1/offset for fast searching */
1188         QSORT(ofs_deltas, nr_ofs_deltas, compare_ofs_delta_entry);
1189         QSORT(ref_deltas, nr_ref_deltas, compare_ref_delta_entry);
1190
1191         if (verbose || show_resolving_progress)
1192                 progress = start_progress(_("Resolving deltas"),
1193                                           nr_ref_deltas + nr_ofs_deltas);
1194
1195         nr_dispatched = 0;
1196         if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) {
1197                 init_thread();
1198                 for (i = 0; i < nr_threads; i++) {
1199                         int ret = pthread_create(&thread_data[i].thread, NULL,
1200                                                  threaded_second_pass, thread_data + i);
1201                         if (ret)
1202                                 die(_("unable to create thread: %s"),
1203                                     strerror(ret));
1204                 }
1205                 for (i = 0; i < nr_threads; i++)
1206                         pthread_join(thread_data[i].thread, NULL);
1207                 cleanup_thread();
1208                 return;
1209         }
1210         threaded_second_pass(&nothread_data);
1211 }
1212
1213 /*
1214  * Third pass:
1215  * - append objects to convert thin pack to full pack if required
1216  * - write the final pack hash
1217  */
1218 static void fix_unresolved_deltas(struct hashfile *f);
1219 static void conclude_pack(int fix_thin_pack, const char *curr_pack, unsigned char *pack_hash)
1220 {
1221         if (nr_ref_deltas + nr_ofs_deltas == nr_resolved_deltas) {
1222                 stop_progress(&progress);
1223                 /* Flush remaining pack final hash. */
1224                 flush();
1225                 return;
1226         }
1227
1228         if (fix_thin_pack) {
1229                 struct hashfile *f;
1230                 unsigned char read_hash[GIT_MAX_RAWSZ], tail_hash[GIT_MAX_RAWSZ];
1231                 struct strbuf msg = STRBUF_INIT;
1232                 int nr_unresolved = nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas;
1233                 int nr_objects_initial = nr_objects;
1234                 if (nr_unresolved <= 0)
1235                         die(_("confusion beyond insanity"));
1236                 REALLOC_ARRAY(objects, nr_objects + nr_unresolved + 1);
1237                 memset(objects + nr_objects + 1, 0,
1238                        nr_unresolved * sizeof(*objects));
1239                 f = hashfd(output_fd, curr_pack);
1240                 fix_unresolved_deltas(f);
1241                 strbuf_addf(&msg, Q_("completed with %d local object",
1242                                      "completed with %d local objects",
1243                                      nr_objects - nr_objects_initial),
1244                             nr_objects - nr_objects_initial);
1245                 stop_progress_msg(&progress, msg.buf);
1246                 strbuf_release(&msg);
1247                 finalize_hashfile(f, tail_hash, 0);
1248                 hashcpy(read_hash, pack_hash);
1249                 fixup_pack_header_footer(output_fd, pack_hash,
1250                                          curr_pack, nr_objects,
1251                                          read_hash, consumed_bytes-the_hash_algo->rawsz);
1252                 if (!hasheq(read_hash, tail_hash))
1253                         die(_("Unexpected tail checksum for %s "
1254                               "(disk corruption?)"), curr_pack);
1255         }
1256         if (nr_ofs_deltas + nr_ref_deltas != nr_resolved_deltas)
1257                 die(Q_("pack has %d unresolved delta",
1258                        "pack has %d unresolved deltas",
1259                        nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas),
1260                     nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas);
1261 }
1262
1263 static int write_compressed(struct hashfile *f, void *in, unsigned int size)
1264 {
1265         git_zstream stream;
1266         int status;
1267         unsigned char outbuf[4096];
1268
1269         git_deflate_init(&stream, zlib_compression_level);
1270         stream.next_in = in;
1271         stream.avail_in = size;
1272
1273         do {
1274                 stream.next_out = outbuf;
1275                 stream.avail_out = sizeof(outbuf);
1276                 status = git_deflate(&stream, Z_FINISH);
1277                 hashwrite(f, outbuf, sizeof(outbuf) - stream.avail_out);
1278         } while (status == Z_OK);
1279
1280         if (status != Z_STREAM_END)
1281                 die(_("unable to deflate appended object (%d)"), status);
1282         size = stream.total_out;
1283         git_deflate_end(&stream);
1284         return size;
1285 }
1286
1287 static struct object_entry *append_obj_to_pack(struct hashfile *f,
1288                                const unsigned char *sha1, void *buf,
1289                                unsigned long size, enum object_type type)
1290 {
1291         struct object_entry *obj = &objects[nr_objects++];
1292         unsigned char header[10];
1293         unsigned long s = size;
1294         int n = 0;
1295         unsigned char c = (type << 4) | (s & 15);
1296         s >>= 4;
1297         while (s) {
1298                 header[n++] = c | 0x80;
1299                 c = s & 0x7f;
1300                 s >>= 7;
1301         }
1302         header[n++] = c;
1303         crc32_begin(f);
1304         hashwrite(f, header, n);
1305         obj[0].size = size;
1306         obj[0].hdr_size = n;
1307         obj[0].type = type;
1308         obj[0].real_type = type;
1309         obj[1].idx.offset = obj[0].idx.offset + n;
1310         obj[1].idx.offset += write_compressed(f, buf, size);
1311         obj[0].idx.crc32 = crc32_end(f);
1312         hashflush(f);
1313         hashcpy(obj->idx.oid.hash, sha1);
1314         return obj;
1315 }
1316
1317 static int delta_pos_compare(const void *_a, const void *_b)
1318 {
1319         struct ref_delta_entry *a = *(struct ref_delta_entry **)_a;
1320         struct ref_delta_entry *b = *(struct ref_delta_entry **)_b;
1321         return a->obj_no - b->obj_no;
1322 }
1323
1324 static void fix_unresolved_deltas(struct hashfile *f)
1325 {
1326         struct ref_delta_entry **sorted_by_pos;
1327         int i;
1328
1329         /*
1330          * Since many unresolved deltas may well be themselves base objects
1331          * for more unresolved deltas, we really want to include the
1332          * smallest number of base objects that would cover as much delta
1333          * as possible by picking the
1334          * trunc deltas first, allowing for other deltas to resolve without
1335          * additional base objects.  Since most base objects are to be found
1336          * before deltas depending on them, a good heuristic is to start
1337          * resolving deltas in the same order as their position in the pack.
1338          */
1339         ALLOC_ARRAY(sorted_by_pos, nr_ref_deltas);
1340         for (i = 0; i < nr_ref_deltas; i++)
1341                 sorted_by_pos[i] = &ref_deltas[i];
1342         QSORT(sorted_by_pos, nr_ref_deltas, delta_pos_compare);
1343
1344         if (has_promisor_remote()) {
1345                 /*
1346                  * Prefetch the delta bases.
1347                  */
1348                 struct oid_array to_fetch = OID_ARRAY_INIT;
1349                 for (i = 0; i < nr_ref_deltas; i++) {
1350                         struct ref_delta_entry *d = sorted_by_pos[i];
1351                         if (!oid_object_info_extended(the_repository, &d->oid,
1352                                                       NULL,
1353                                                       OBJECT_INFO_FOR_PREFETCH))
1354                                 continue;
1355                         oid_array_append(&to_fetch, &d->oid);
1356                 }
1357                 promisor_remote_get_direct(the_repository,
1358                                            to_fetch.oid, to_fetch.nr);
1359                 oid_array_clear(&to_fetch);
1360         }
1361
1362         for (i = 0; i < nr_ref_deltas; i++) {
1363                 struct ref_delta_entry *d = sorted_by_pos[i];
1364                 enum object_type type;
1365                 struct base_data *base;
1366                 void *data;
1367                 unsigned long size;
1368                 struct object_entry *obj;
1369
1370                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
1371                         continue;
1372                 data = read_object_file(&d->oid, &type, &size);
1373                 if (!data)
1374                         continue;
1375
1376                 if (check_object_signature(the_repository, &d->oid,
1377                                            data, size,
1378                                            type_name(type)))
1379                         die(_("local object %s is corrupt"), oid_to_hex(&d->oid));
1380                 obj = append_obj_to_pack(f, d->oid.hash, data, size, type);
1381                 base = make_base(obj, NULL);
1382                 base->data = data;
1383                 base->size = size;
1384                 find_unresolved_deltas(base);
1385                 display_progress(progress, nr_resolved_deltas);
1386         }
1387         free(sorted_by_pos);
1388 }
1389
1390 static const char *derive_filename(const char *pack_name, const char *suffix,
1391                                    struct strbuf *buf)
1392 {
1393         size_t len;
1394         if (!strip_suffix(pack_name, ".pack", &len))
1395                 die(_("packfile name '%s' does not end with '.pack'"),
1396                     pack_name);
1397         strbuf_add(buf, pack_name, len);
1398         strbuf_addch(buf, '.');
1399         strbuf_addstr(buf, suffix);
1400         return buf->buf;
1401 }
1402
1403 static void write_special_file(const char *suffix, const char *msg,
1404                                const char *pack_name, const unsigned char *hash,
1405                                const char **report)
1406 {
1407         struct strbuf name_buf = STRBUF_INIT;
1408         const char *filename;
1409         int fd;
1410         int msg_len = strlen(msg);
1411
1412         if (pack_name)
1413                 filename = derive_filename(pack_name, suffix, &name_buf);
1414         else
1415                 filename = odb_pack_name(&name_buf, hash, suffix);
1416
1417         fd = odb_pack_keep(filename);
1418         if (fd < 0) {
1419                 if (errno != EEXIST)
1420                         die_errno(_("cannot write %s file '%s'"),
1421                                   suffix, filename);
1422         } else {
1423                 if (msg_len > 0) {
1424                         write_or_die(fd, msg, msg_len);
1425                         write_or_die(fd, "\n", 1);
1426                 }
1427                 if (close(fd) != 0)
1428                         die_errno(_("cannot close written %s file '%s'"),
1429                                   suffix, filename);
1430                 if (report)
1431                         *report = suffix;
1432         }
1433         strbuf_release(&name_buf);
1434 }
1435
1436 static void final(const char *final_pack_name, const char *curr_pack_name,
1437                   const char *final_index_name, const char *curr_index_name,
1438                   const char *keep_msg, const char *promisor_msg,
1439                   unsigned char *hash)
1440 {
1441         const char *report = "pack";
1442         struct strbuf pack_name = STRBUF_INIT;
1443         struct strbuf index_name = STRBUF_INIT;
1444         int err;
1445
1446         if (!from_stdin) {
1447                 close(input_fd);
1448         } else {
1449                 fsync_or_die(output_fd, curr_pack_name);
1450                 err = close(output_fd);
1451                 if (err)
1452                         die_errno(_("error while closing pack file"));
1453         }
1454
1455         if (keep_msg)
1456                 write_special_file("keep", keep_msg, final_pack_name, hash,
1457                                    &report);
1458         if (promisor_msg)
1459                 write_special_file("promisor", promisor_msg, final_pack_name,
1460                                    hash, NULL);
1461
1462         if (final_pack_name != curr_pack_name) {
1463                 if (!final_pack_name)
1464                         final_pack_name = odb_pack_name(&pack_name, hash, "pack");
1465                 if (finalize_object_file(curr_pack_name, final_pack_name))
1466                         die(_("cannot store pack file"));
1467         } else if (from_stdin)
1468                 chmod(final_pack_name, 0444);
1469
1470         if (final_index_name != curr_index_name) {
1471                 if (!final_index_name)
1472                         final_index_name = odb_pack_name(&index_name, hash, "idx");
1473                 if (finalize_object_file(curr_index_name, final_index_name))
1474                         die(_("cannot store index file"));
1475         } else
1476                 chmod(final_index_name, 0444);
1477
1478         if (do_fsck_object) {
1479                 struct packed_git *p;
1480                 p = add_packed_git(final_index_name, strlen(final_index_name), 0);
1481                 if (p)
1482                         install_packed_git(the_repository, p);
1483         }
1484
1485         if (!from_stdin) {
1486                 printf("%s\n", hash_to_hex(hash));
1487         } else {
1488                 struct strbuf buf = STRBUF_INIT;
1489
1490                 strbuf_addf(&buf, "%s\t%s\n", report, hash_to_hex(hash));
1491                 write_or_die(1, buf.buf, buf.len);
1492                 strbuf_release(&buf);
1493
1494                 /*
1495                  * Let's just mimic git-unpack-objects here and write
1496                  * the last part of the input buffer to stdout.
1497                  */
1498                 while (input_len) {
1499                         err = xwrite(1, input_buffer + input_offset, input_len);
1500                         if (err <= 0)
1501                                 break;
1502                         input_len -= err;
1503                         input_offset += err;
1504                 }
1505         }
1506
1507         strbuf_release(&index_name);
1508         strbuf_release(&pack_name);
1509 }
1510
1511 static int git_index_pack_config(const char *k, const char *v, void *cb)
1512 {
1513         struct pack_idx_option *opts = cb;
1514
1515         if (!strcmp(k, "pack.indexversion")) {
1516                 opts->version = git_config_int(k, v);
1517                 if (opts->version > 2)
1518                         die(_("bad pack.indexversion=%"PRIu32), opts->version);
1519                 return 0;
1520         }
1521         if (!strcmp(k, "pack.threads")) {
1522                 nr_threads = git_config_int(k, v);
1523                 if (nr_threads < 0)
1524                         die(_("invalid number of threads specified (%d)"),
1525                             nr_threads);
1526                 if (!HAVE_THREADS && nr_threads != 1) {
1527                         warning(_("no threads support, ignoring %s"), k);
1528                         nr_threads = 1;
1529                 }
1530                 return 0;
1531         }
1532         return git_default_config(k, v, cb);
1533 }
1534
1535 static int cmp_uint32(const void *a_, const void *b_)
1536 {
1537         uint32_t a = *((uint32_t *)a_);
1538         uint32_t b = *((uint32_t *)b_);
1539
1540         return (a < b) ? -1 : (a != b);
1541 }
1542
1543 static void read_v2_anomalous_offsets(struct packed_git *p,
1544                                       struct pack_idx_option *opts)
1545 {
1546         const uint32_t *idx1, *idx2;
1547         uint32_t i;
1548
1549         /* The address of the 4-byte offset table */
1550         idx1 = (((const uint32_t *)((const uint8_t *)p->index_data + p->crc_offset))
1551                 + p->num_objects /* CRC32 table */
1552                 );
1553
1554         /* The address of the 8-byte offset table */
1555         idx2 = idx1 + p->num_objects;
1556
1557         for (i = 0; i < p->num_objects; i++) {
1558                 uint32_t off = ntohl(idx1[i]);
1559                 if (!(off & 0x80000000))
1560                         continue;
1561                 off = off & 0x7fffffff;
1562                 check_pack_index_ptr(p, &idx2[off * 2]);
1563                 if (idx2[off * 2])
1564                         continue;
1565                 /*
1566                  * The real offset is ntohl(idx2[off * 2]) in high 4
1567                  * octets, and ntohl(idx2[off * 2 + 1]) in low 4
1568                  * octets.  But idx2[off * 2] is Zero!!!
1569                  */
1570                 ALLOC_GROW(opts->anomaly, opts->anomaly_nr + 1, opts->anomaly_alloc);
1571                 opts->anomaly[opts->anomaly_nr++] = ntohl(idx2[off * 2 + 1]);
1572         }
1573
1574         QSORT(opts->anomaly, opts->anomaly_nr, cmp_uint32);
1575 }
1576
1577 static void read_idx_option(struct pack_idx_option *opts, const char *pack_name)
1578 {
1579         struct packed_git *p = add_packed_git(pack_name, strlen(pack_name), 1);
1580
1581         if (!p)
1582                 die(_("Cannot open existing pack file '%s'"), pack_name);
1583         if (open_pack_index(p))
1584                 die(_("Cannot open existing pack idx file for '%s'"), pack_name);
1585
1586         /* Read the attributes from the existing idx file */
1587         opts->version = p->index_version;
1588
1589         if (opts->version == 2)
1590                 read_v2_anomalous_offsets(p, opts);
1591
1592         /*
1593          * Get rid of the idx file as we do not need it anymore.
1594          * NEEDSWORK: extract this bit from free_pack_by_name() in
1595          * sha1-file.c, perhaps?  It shouldn't matter very much as we
1596          * know we haven't installed this pack (hence we never have
1597          * read anything from it).
1598          */
1599         close_pack_index(p);
1600         free(p);
1601 }
1602
1603 static void show_pack_info(int stat_only)
1604 {
1605         int i, baseobjects = nr_objects - nr_ref_deltas - nr_ofs_deltas;
1606         unsigned long *chain_histogram = NULL;
1607
1608         if (deepest_delta)
1609                 chain_histogram = xcalloc(deepest_delta, sizeof(unsigned long));
1610
1611         for (i = 0; i < nr_objects; i++) {
1612                 struct object_entry *obj = &objects[i];
1613
1614                 if (is_delta_type(obj->type))
1615                         chain_histogram[obj_stat[i].delta_depth - 1]++;
1616                 if (stat_only)
1617                         continue;
1618                 printf("%s %-6s %"PRIuMAX" %"PRIuMAX" %"PRIuMAX,
1619                        oid_to_hex(&obj->idx.oid),
1620                        type_name(obj->real_type), (uintmax_t)obj->size,
1621                        (uintmax_t)(obj[1].idx.offset - obj->idx.offset),
1622                        (uintmax_t)obj->idx.offset);
1623                 if (is_delta_type(obj->type)) {
1624                         struct object_entry *bobj = &objects[obj_stat[i].base_object_no];
1625                         printf(" %u %s", obj_stat[i].delta_depth,
1626                                oid_to_hex(&bobj->idx.oid));
1627                 }
1628                 putchar('\n');
1629         }
1630
1631         if (baseobjects)
1632                 printf_ln(Q_("non delta: %d object",
1633                              "non delta: %d objects",
1634                              baseobjects),
1635                           baseobjects);
1636         for (i = 0; i < deepest_delta; i++) {
1637                 if (!chain_histogram[i])
1638                         continue;
1639                 printf_ln(Q_("chain length = %d: %lu object",
1640                              "chain length = %d: %lu objects",
1641                              chain_histogram[i]),
1642                           i + 1,
1643                           chain_histogram[i]);
1644         }
1645 }
1646
1647 int cmd_index_pack(int argc, const char **argv, const char *prefix)
1648 {
1649         int i, fix_thin_pack = 0, verify = 0, stat_only = 0;
1650         const char *curr_index;
1651         const char *index_name = NULL, *pack_name = NULL;
1652         const char *keep_msg = NULL;
1653         const char *promisor_msg = NULL;
1654         struct strbuf index_name_buf = STRBUF_INIT;
1655         struct pack_idx_entry **idx_objects;
1656         struct pack_idx_option opts;
1657         unsigned char pack_hash[GIT_MAX_RAWSZ];
1658         unsigned foreign_nr = 1;        /* zero is a "good" value, assume bad */
1659         int report_end_of_input = 0;
1660         int hash_algo = 0;
1661
1662         /*
1663          * index-pack never needs to fetch missing objects except when
1664          * REF_DELTA bases are missing (which are explicitly handled). It only
1665          * accesses the repo to do hash collision checks and to check which
1666          * REF_DELTA bases need to be fetched.
1667          */
1668         fetch_if_missing = 0;
1669
1670         if (argc == 2 && !strcmp(argv[1], "-h"))
1671                 usage(index_pack_usage);
1672
1673         read_replace_refs = 0;
1674         fsck_options.walk = mark_link;
1675
1676         reset_pack_idx_option(&opts);
1677         git_config(git_index_pack_config, &opts);
1678         if (prefix && chdir(prefix))
1679                 die(_("Cannot come back to cwd"));
1680
1681         for (i = 1; i < argc; i++) {
1682                 const char *arg = argv[i];
1683
1684                 if (*arg == '-') {
1685                         if (!strcmp(arg, "--stdin")) {
1686                                 from_stdin = 1;
1687                         } else if (!strcmp(arg, "--fix-thin")) {
1688                                 fix_thin_pack = 1;
1689                         } else if (skip_to_optional_arg(arg, "--strict", &arg)) {
1690                                 strict = 1;
1691                                 do_fsck_object = 1;
1692                                 fsck_set_msg_types(&fsck_options, arg);
1693                         } else if (!strcmp(arg, "--check-self-contained-and-connected")) {
1694                                 strict = 1;
1695                                 check_self_contained_and_connected = 1;
1696                         } else if (!strcmp(arg, "--fsck-objects")) {
1697                                 do_fsck_object = 1;
1698                         } else if (!strcmp(arg, "--verify")) {
1699                                 verify = 1;
1700                         } else if (!strcmp(arg, "--verify-stat")) {
1701                                 verify = 1;
1702                                 show_stat = 1;
1703                         } else if (!strcmp(arg, "--verify-stat-only")) {
1704                                 verify = 1;
1705                                 show_stat = 1;
1706                                 stat_only = 1;
1707                         } else if (skip_to_optional_arg(arg, "--keep", &keep_msg)) {
1708                                 ; /* nothing to do */
1709                         } else if (skip_to_optional_arg(arg, "--promisor", &promisor_msg)) {
1710                                 ; /* already parsed */
1711                         } else if (starts_with(arg, "--threads=")) {
1712                                 char *end;
1713                                 nr_threads = strtoul(arg+10, &end, 0);
1714                                 if (!arg[10] || *end || nr_threads < 0)
1715                                         usage(index_pack_usage);
1716                                 if (!HAVE_THREADS && nr_threads != 1) {
1717                                         warning(_("no threads support, ignoring %s"), arg);
1718                                         nr_threads = 1;
1719                                 }
1720                         } else if (starts_with(arg, "--pack_header=")) {
1721                                 struct pack_header *hdr;
1722                                 char *c;
1723
1724                                 hdr = (struct pack_header *)input_buffer;
1725                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
1726                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
1727                                 if (*c != ',')
1728                                         die(_("bad %s"), arg);
1729                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
1730                                 if (*c)
1731                                         die(_("bad %s"), arg);
1732                                 input_len = sizeof(*hdr);
1733                         } else if (!strcmp(arg, "-v")) {
1734                                 verbose = 1;
1735                         } else if (!strcmp(arg, "--show-resolving-progress")) {
1736                                 show_resolving_progress = 1;
1737                         } else if (!strcmp(arg, "--report-end-of-input")) {
1738                                 report_end_of_input = 1;
1739                         } else if (!strcmp(arg, "-o")) {
1740                                 if (index_name || (i+1) >= argc)
1741                                         usage(index_pack_usage);
1742                                 index_name = argv[++i];
1743                         } else if (starts_with(arg, "--index-version=")) {
1744                                 char *c;
1745                                 opts.version = strtoul(arg + 16, &c, 10);
1746                                 if (opts.version > 2)
1747                                         die(_("bad %s"), arg);
1748                                 if (*c == ',')
1749                                         opts.off32_limit = strtoul(c+1, &c, 0);
1750                                 if (*c || opts.off32_limit & 0x80000000)
1751                                         die(_("bad %s"), arg);
1752                         } else if (skip_prefix(arg, "--max-input-size=", &arg)) {
1753                                 max_input_size = strtoumax(arg, NULL, 10);
1754                         } else if (skip_prefix(arg, "--object-format=", &arg)) {
1755                                 hash_algo = hash_algo_by_name(arg);
1756                                 if (hash_algo == GIT_HASH_UNKNOWN)
1757                                         die(_("unknown hash algorithm '%s'"), arg);
1758                                 repo_set_hash_algo(the_repository, hash_algo);
1759                         } else
1760                                 usage(index_pack_usage);
1761                         continue;
1762                 }
1763
1764                 if (pack_name)
1765                         usage(index_pack_usage);
1766                 pack_name = arg;
1767         }
1768
1769         if (!pack_name && !from_stdin)
1770                 usage(index_pack_usage);
1771         if (fix_thin_pack && !from_stdin)
1772                 die(_("--fix-thin cannot be used without --stdin"));
1773         if (from_stdin && !startup_info->have_repository)
1774                 die(_("--stdin requires a git repository"));
1775         if (from_stdin && hash_algo)
1776                 die(_("--object-format cannot be used with --stdin"));
1777         if (!index_name && pack_name)
1778                 index_name = derive_filename(pack_name, "idx", &index_name_buf);
1779
1780         if (verify) {
1781                 if (!index_name)
1782                         die(_("--verify with no packfile name given"));
1783                 read_idx_option(&opts, index_name);
1784                 opts.flags |= WRITE_IDX_VERIFY | WRITE_IDX_STRICT;
1785         }
1786         if (strict)
1787                 opts.flags |= WRITE_IDX_STRICT;
1788
1789         if (HAVE_THREADS && !nr_threads) {
1790                 nr_threads = online_cpus();
1791                 /* An experiment showed that more threads does not mean faster */
1792                 if (nr_threads > 3)
1793                         nr_threads = 3;
1794         }
1795
1796         curr_pack = open_pack_file(pack_name);
1797         parse_pack_header();
1798         objects = xcalloc(st_add(nr_objects, 1), sizeof(struct object_entry));
1799         if (show_stat)
1800                 obj_stat = xcalloc(st_add(nr_objects, 1), sizeof(struct object_stat));
1801         ofs_deltas = xcalloc(nr_objects, sizeof(struct ofs_delta_entry));
1802         parse_pack_objects(pack_hash);
1803         if (report_end_of_input)
1804                 write_in_full(2, "\0", 1);
1805         resolve_deltas();
1806         conclude_pack(fix_thin_pack, curr_pack, pack_hash);
1807         free(ofs_deltas);
1808         free(ref_deltas);
1809         if (strict)
1810                 foreign_nr = check_objects();
1811
1812         if (show_stat)
1813                 show_pack_info(stat_only);
1814
1815         ALLOC_ARRAY(idx_objects, nr_objects);
1816         for (i = 0; i < nr_objects; i++)
1817                 idx_objects[i] = &objects[i].idx;
1818         curr_index = write_idx_file(index_name, idx_objects, nr_objects, &opts, pack_hash);
1819         free(idx_objects);
1820
1821         if (!verify)
1822                 final(pack_name, curr_pack,
1823                       index_name, curr_index,
1824                       keep_msg, promisor_msg,
1825                       pack_hash);
1826         else
1827                 close(input_fd);
1828
1829         if (do_fsck_object && fsck_finish(&fsck_options))
1830                 die(_("fsck error in pack objects"));
1831
1832         free(objects);
1833         strbuf_release(&index_name_buf);
1834         if (pack_name == NULL)
1835                 free((void *) curr_pack);
1836         if (index_name == NULL)
1837                 free((void *) curr_index);
1838
1839         /*
1840          * Let the caller know this pack is not self contained
1841          */
1842         if (check_self_contained_and_connected && foreign_nr)
1843                 return 1;
1844
1845         return 0;
1846 }