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
  18 static const char index_pack_usage[] =
  19 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
  20
  21 struct object_entry {
  22         struct pack_idx_entry idx;
  23         unsigned long size;
  24         unsigned char hdr_size;
  25         signed char type;
  26         signed char real_type;
  27 };
  28
  29 struct object_stat {
  30         unsigned delta_depth;
  31         int base_object_no;
  32 };
  33
  34 struct base_data {
  35         struct base_data *base;
  36         struct base_data *child;
  37         struct object_entry *obj;
  38         void *data;
  39         unsigned long size;
  40         int ref_first, ref_last;
  41         int ofs_first, ofs_last;
  42 };
  43
  44 struct thread_local {
  45         pthread_t thread;
  46         struct base_data *base_cache;
  47         size_t base_cache_used;
  48         int pack_fd;
  49 };
  50
  51 /* Remember to update object flag allocation in object.h */
  52 #define FLAG_LINK (1u<<20)
  53 #define FLAG_CHECKED (1u<<21)
  54
  55 struct ofs_delta_entry {
  56         off_t offset;
  57         int obj_no;
  58 };
  59
  60 struct ref_delta_entry {
  61         struct object_id oid;
  62         int obj_no;
  63 };
  64
  65 static struct object_entry *objects;
  66 static struct object_stat *obj_stat;
  67 static struct ofs_delta_entry *ofs_deltas;
  68 static struct ref_delta_entry *ref_deltas;
  69 static struct thread_local nothread_data;
  70 static int nr_objects;
  71 static int nr_ofs_deltas;
  72 static int nr_ref_deltas;
  73 static int ref_deltas_alloc;
  74 static int nr_resolved_deltas;
  75 static int nr_threads;
  76
  77 static int from_stdin;
  78 static int strict;
  79 static int do_fsck_object;
  80 static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
  81 static int verbose;
  82 static int show_resolving_progress;
  83 static int show_stat;
  84 static int check_self_contained_and_connected;
  85
  86 static struct progress *progress;
  87
  88 /* We always read in 4kB chunks. */
  89 static unsigned char input_buffer[4096];
  90 static unsigned int input_offset, input_len;
  91 static off_t consumed_bytes;
  92 static off_t max_input_size;
  93 static unsigned deepest_delta;
  94 static git_hash_ctx input_ctx;
  95 static uint32_t input_crc32;
  96 static int input_fd, output_fd;
  97 static const char *curr_pack;
  98
  99 static struct thread_local *thread_data;
 100 static int nr_dispatched;
 101 static int threads_active;
 102
 103 static pthread_mutex_t read_mutex;
 104 #define read_lock()             lock_mutex(&read_mutex)
 105 #define read_unlock()           unlock_mutex(&read_mutex)
 106
 107 static pthread_mutex_t counter_mutex;
 108 #define counter_lock()          lock_mutex(&counter_mutex)
 109 #define counter_unlock()        unlock_mutex(&counter_mutex)
 110
 111 static pthread_mutex_t work_mutex;
 112 #define work_lock()             lock_mutex(&work_mutex)
 113 #define work_unlock()           unlock_mutex(&work_mutex)
 114
 115 static pthread_mutex_t deepest_delta_mutex;
 116 #define deepest_delta_lock()    lock_mutex(&deepest_delta_mutex)
 117 #define deepest_delta_unlock()  unlock_mutex(&deepest_delta_mutex)
 118
 119 static pthread_mutex_t type_cas_mutex;
 120 #define type_cas_lock()         lock_mutex(&type_cas_mutex)
 121 #define type_cas_unlock()       unlock_mutex(&type_cas_mutex)
 122
 123 static pthread_key_t key;
 124
 125 static inline void lock_mutex(pthread_mutex_t *mutex)
 126 {
 127         if (threads_active)
 128                 pthread_mutex_lock(mutex);
 129 }
 130
 131 static inline void unlock_mutex(pthread_mutex_t *mutex)
 132 {
 133         if (threads_active)
 134                 pthread_mutex_unlock(mutex);
 135 }
 136
 137 /*
 138  * Mutex and conditional variable can't be statically-initialized on Windows.
 139  */
 140 static void init_thread(void)
 141 {
 142         int i;
 143         init_recursive_mutex(&read_mutex);
 144         pthread_mutex_init(&counter_mutex, NULL);
 145         pthread_mutex_init(&work_mutex, NULL);
 146         pthread_mutex_init(&type_cas_mutex, NULL);
 147         if (show_stat)
 148                 pthread_mutex_init(&deepest_delta_mutex, NULL);
 149         pthread_key_create(&key, NULL);
 150         thread_data = xcalloc(nr_threads, sizeof(*thread_data));
 151         for (i = 0; i < nr_threads; i++) {
 152                 thread_data[i].pack_fd = open(curr_pack, O_RDONLY);
 153                 if (thread_data[i].pack_fd == -1)
 154                         die_errno(_("unable to open %s"), curr_pack);
 155         }
 156
 157         threads_active = 1;
 158 }
 159
 160 static void cleanup_thread(void)
 161 {
 162         int i;
 163         if (!threads_active)
 164                 return;
 165         threads_active = 0;
 166         pthread_mutex_destroy(&read_mutex);
 167         pthread_mutex_destroy(&counter_mutex);
 168         pthread_mutex_destroy(&work_mutex);
 169         pthread_mutex_destroy(&type_cas_mutex);
 170         if (show_stat)
 171                 pthread_mutex_destroy(&deepest_delta_mutex);
 172         for (i = 0; i < nr_threads; i++)
 173                 close(thread_data[i].pack_fd);
 174         pthread_key_delete(key);
 175         free(thread_data);
 176 }
 177
 178 static int mark_link(struct object *obj, int type, void *data, struct fsck_options *options)
 179 {
 180         if (!obj)
 181                 return -1;
 182
 183         if (type != OBJ_ANY && obj->type != type)
 184                 die(_("object type mismatch at %s"), oid_to_hex(&obj->oid));
 185
 186         obj->flags |= FLAG_LINK;
 187         return 0;
 188 }
 189
 190 /* The content of each linked object must have been checked
 191    or it must be already present in the object database */
 192 static unsigned check_object(struct object *obj)
 193 {
 194         if (!obj)
 195                 return 0;
 196
 197         if (!(obj->flags & FLAG_LINK))
 198                 return 0;
 199
 200         if (!(obj->flags & FLAG_CHECKED)) {
 201                 unsigned long size;
 202                 int type = oid_object_info(the_repository, &obj->oid, &size);
 203                 if (type <= 0)
 204                         die(_("did not receive expected object %s"),
 205                               oid_to_hex(&obj->oid));
 206                 if (type != obj->type)
 207                         die(_("object %s: expected type %s, found %s"),
 208                             oid_to_hex(&obj->oid),
 209                             type_name(obj->type), type_name(type));
 210                 obj->flags |= FLAG_CHECKED;
 211                 return 1;
 212         }
 213
 214         return 0;
 215 }
 216
 217 static unsigned check_objects(void)
 218 {
 219         unsigned i, max, foreign_nr = 0;
 220
 221         max = get_max_object_index();
 222         for (i = 0; i < max; i++)
 223                 foreign_nr += check_object(get_indexed_object(i));
 224         return foreign_nr;
 225 }
 226
 227
 228 /* Discard current buffer used content. */
 229 static void flush(void)
 230 {
 231         if (input_offset) {
 232                 if (output_fd >= 0)
 233                         write_or_die(output_fd, input_buffer, input_offset);
 234                 the_hash_algo->update_fn(&input_ctx, input_buffer, input_offset);
 235                 memmove(input_buffer, input_buffer + input_offset, input_len);
 236                 input_offset = 0;
 237         }
 238 }
 239
 240 /*
 241  * Make sure at least "min" bytes are available in the buffer, and
 242  * return the pointer to the buffer.
 243  */
 244 static void *fill(int min)
 245 {
 246         if (min <= input_len)
 247                 return input_buffer + input_offset;
 248         if (min > sizeof(input_buffer))
 249                 die(Q_("cannot fill %d byte",
 250                        "cannot fill %d bytes",
 251                        min),
 252                     min);
 253         flush();
 254         do {
 255                 ssize_t ret = xread(input_fd, input_buffer + input_len,
 256                                 sizeof(input_buffer) - input_len);
 257                 if (ret <= 0) {
 258                         if (!ret)
 259                                 die(_("early EOF"));
 260                         die_errno(_("read error on input"));
 261                 }
 262                 input_len += ret;
 263                 if (from_stdin)
 264                         display_throughput(progress, consumed_bytes + input_len);
 265         } while (input_len < min);
 266         return input_buffer;
 267 }
 268
 269 static void use(int bytes)
 270 {
 271         if (bytes > input_len)
 272                 die(_("used more bytes than were available"));
 273         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 274         input_len -= bytes;
 275         input_offset += bytes;
 276
 277         /* make sure off_t is sufficiently large not to wrap */
 278         if (signed_add_overflows(consumed_bytes, bytes))
 279                 die(_("pack too large for current definition of off_t"));
 280         consumed_bytes += bytes;
 281         if (max_input_size && consumed_bytes > max_input_size)
 282                 die(_("pack exceeds maximum allowed size"));
 283 }
 284
 285 static const char *open_pack_file(const char *pack_name)
 286 {
 287         if (from_stdin) {
 288                 input_fd = 0;
 289                 if (!pack_name) {
 290                         struct strbuf tmp_file = STRBUF_INIT;
 291                         output_fd = odb_mkstemp(&tmp_file,
 292                                                 "pack/tmp_pack_XXXXXX");
 293                         pack_name = strbuf_detach(&tmp_file, NULL);
 294                 } else {
 295                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 296                         if (output_fd < 0)
 297                                 die_errno(_("unable to create '%s'"), pack_name);
 298                 }
 299                 nothread_data.pack_fd = output_fd;
 300         } else {
 301                 input_fd = open(pack_name, O_RDONLY);
 302                 if (input_fd < 0)
 303                         die_errno(_("cannot open packfile '%s'"), pack_name);
 304                 output_fd = -1;
 305                 nothread_data.pack_fd = input_fd;
 306         }
 307         the_hash_algo->init_fn(&input_ctx);
 308         return pack_name;
 309 }
 310
 311 static void parse_pack_header(void)
 312 {
 313         struct pack_header *hdr = fill(sizeof(struct pack_header));
 314
 315         /* Header consistency check */
 316         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 317                 die(_("pack signature mismatch"));
 318         if (!pack_version_ok(hdr->hdr_version))
 319                 die(_("pack version %"PRIu32" unsupported"),
 320                         ntohl(hdr->hdr_version));
 321
 322         nr_objects = ntohl(hdr->hdr_entries);
 323         use(sizeof(struct pack_header));
 324 }
 325
 326 static NORETURN void bad_object(off_t offset, const char *format,
 327                        ...) __attribute__((format (printf, 2, 3)));
 328
 329 static NORETURN void bad_object(off_t offset, const char *format, ...)
 330 {
 331         va_list params;
 332         char buf[1024];
 333
 334         va_start(params, format);
 335         vsnprintf(buf, sizeof(buf), format, params);
 336         va_end(params);
 337         die(_("pack has bad object at offset %"PRIuMAX": %s"),
 338             (uintmax_t)offset, buf);
 339 }
 340
 341 static inline struct thread_local *get_thread_data(void)
 342 {
 343         if (HAVE_THREADS) {
 344                 if (threads_active)
 345                         return pthread_getspecific(key);
 346                 assert(!threads_active &&
 347                        "This should only be reached when all threads are gone");
 348         }
 349         return &nothread_data;
 350 }
 351
 352 static void set_thread_data(struct thread_local *data)
 353 {
 354         if (threads_active)
 355                 pthread_setspecific(key, data);
 356 }
 357
 358 static struct base_data *alloc_base_data(void)
 359 {
 360         struct base_data *base = xcalloc(1, sizeof(struct base_data));
 361         base->ref_last = -1;
 362         base->ofs_last = -1;
 363         return base;
 364 }
 365
 366 static void free_base_data(struct base_data *c)
 367 {
 368         if (c->data) {
 369                 FREE_AND_NULL(c->data);
 370                 get_thread_data()->base_cache_used -= c->size;
 371         }
 372 }
 373
 374 static void prune_base_data(struct base_data *retain)
 375 {
 376         struct base_data *b;
 377         struct thread_local *data = get_thread_data();
 378         for (b = data->base_cache;
 379              data->base_cache_used > delta_base_cache_limit && b;
 380              b = b->child) {
 381                 if (b->data && b != retain)
 382                         free_base_data(b);
 383         }
 384 }
 385
 386 static void link_base_data(struct base_data *base, struct base_data *c)
 387 {
 388         if (base)
 389                 base->child = c;
 390         else
 391                 get_thread_data()->base_cache = c;
 392
 393         c->base = base;
 394         c->child = NULL;
 395         if (c->data)
 396                 get_thread_data()->base_cache_used += c->size;
 397         prune_base_data(c);
 398 }
 399
 400 static void unlink_base_data(struct base_data *c)
 401 {
 402         struct base_data *base = c->base;
 403         if (base)
 404                 base->child = NULL;
 405         else
 406                 get_thread_data()->base_cache = NULL;
 407         free_base_data(c);
 408 }
 409
 410 static int is_delta_type(enum object_type type)
 411 {
 412         return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
 413 }
 414
 415 static void *unpack_entry_data(off_t offset, unsigned long size,
 416                                enum object_type type, struct object_id *oid)
 417 {
 418         static char fixed_buf[8192];
 419         int status;
 420         git_zstream stream;
 421         void *buf;
 422         git_hash_ctx c;
 423         char hdr[32];
 424         int hdrlen;
 425
 426         if (!is_delta_type(type)) {
 427                 hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", type_name(type), size) + 1;
 428                 the_hash_algo->init_fn(&c);
 429                 the_hash_algo->update_fn(&c, hdr, hdrlen);
 430         } else
 431                 oid = NULL;
 432         if (type == OBJ_BLOB && size > big_file_threshold)
 433                 buf = fixed_buf;
 434         else
 435                 buf = xmallocz(size);
 436
 437         memset(&stream, 0, sizeof(stream));
 438         git_inflate_init(&stream);
 439         stream.next_out = buf;
 440         stream.avail_out = buf == fixed_buf ? sizeof(fixed_buf) : size;
 441
 442         do {
 443                 unsigned char *last_out = stream.next_out;
 444                 stream.next_in = fill(1);
 445                 stream.avail_in = input_len;
 446                 status = git_inflate(&stream, 0);
 447                 use(input_len - stream.avail_in);
 448                 if (oid)
 449                         the_hash_algo->update_fn(&c, last_out, stream.next_out - last_out);
 450                 if (buf == fixed_buf) {
 451                         stream.next_out = buf;
 452                         stream.avail_out = sizeof(fixed_buf);
 453                 }
 454         } while (status == Z_OK);
 455         if (stream.total_out != size || status != Z_STREAM_END)
 456                 bad_object(offset, _("inflate returned %d"), status);
 457         git_inflate_end(&stream);
 458         if (oid)
 459                 the_hash_algo->final_fn(oid->hash, &c);
 460         return buf == fixed_buf ? NULL : buf;
 461 }
 462
 463 static void *unpack_raw_entry(struct object_entry *obj,
 464                               off_t *ofs_offset,
 465                               struct object_id *ref_oid,
 466                               struct object_id *oid)
 467 {
 468         unsigned char *p;
 469         unsigned long size, c;
 470         off_t base_offset;
 471         unsigned shift;
 472         void *data;
 473
 474         obj->idx.offset = consumed_bytes;
 475         input_crc32 = crc32(0, NULL, 0);
 476
 477         p = fill(1);
 478         c = *p;
 479         use(1);
 480         obj->type = (c >> 4) & 7;
 481         size = (c & 15);
 482         shift = 4;
 483         while (c & 0x80) {
 484                 p = fill(1);
 485                 c = *p;
 486                 use(1);
 487                 size += (c & 0x7f) << shift;
 488                 shift += 7;
 489         }
 490         obj->size = size;
 491
 492         switch (obj->type) {
 493         case OBJ_REF_DELTA:
 494                 hashcpy(ref_oid->hash, fill(the_hash_algo->rawsz));
 495                 use(the_hash_algo->rawsz);
 496                 break;
 497         case OBJ_OFS_DELTA:
 498                 p = fill(1);
 499                 c = *p;
 500                 use(1);
 501                 base_offset = c & 127;
 502                 while (c & 128) {
 503                         base_offset += 1;
 504                         if (!base_offset || MSB(base_offset, 7))
 505                                 bad_object(obj->idx.offset, _("offset value overflow for delta base object"));
 506                         p = fill(1);
 507                         c = *p;
 508                         use(1);
 509                         base_offset = (base_offset << 7) + (c & 127);
 510                 }
 511                 *ofs_offset = obj->idx.offset - base_offset;
 512                 if (*ofs_offset <= 0 || *ofs_offset >= obj->idx.offset)
 513                         bad_object(obj->idx.offset, _("delta base offset is out of bound"));
 514                 break;
 515         case OBJ_COMMIT:
 516         case OBJ_TREE:
 517         case OBJ_BLOB:
 518         case OBJ_TAG:
 519                 break;
 520         default:
 521                 bad_object(obj->idx.offset, _("unknown object type %d"), obj->type);
 522         }
 523         obj->hdr_size = consumed_bytes - obj->idx.offset;
 524
 525         data = unpack_entry_data(obj->idx.offset, obj->size, obj->type, oid);
 526         obj->idx.crc32 = input_crc32;
 527         return data;
 528 }
 529
 530 static void *unpack_data(struct object_entry *obj,
 531                          int (*consume)(const unsigned char *, unsigned long, void *),
 532                          void *cb_data)
 533 {
 534         off_t from = obj[0].idx.offset + obj[0].hdr_size;
 535         off_t len = obj[1].idx.offset - from;
 536         unsigned char *data, *inbuf;
 537         git_zstream stream;
 538         int status;
 539
 540         data = xmallocz(consume ? 64*1024 : obj->size);
 541         inbuf = xmalloc((len < 64*1024) ? (int)len : 64*1024);
 542
 543         memset(&stream, 0, sizeof(stream));
 544         git_inflate_init(&stream);
 545         stream.next_out = data;
 546         stream.avail_out = consume ? 64*1024 : obj->size;
 547
 548         do {
 549                 ssize_t n = (len < 64*1024) ? (ssize_t)len : 64*1024;
 550                 n = xpread(get_thread_data()->pack_fd, inbuf, n, from);
 551                 if (n < 0)
 552                         die_errno(_("cannot pread pack file"));
 553                 if (!n)
 554                         die(Q_("premature end of pack file, %"PRIuMAX" byte missing",
 555                                "premature end of pack file, %"PRIuMAX" bytes missing",
 556                                (unsigned int)len),
 557                             (uintmax_t)len);
 558                 from += n;
 559                 len -= n;
 560                 stream.next_in = inbuf;
 561                 stream.avail_in = n;
 562                 if (!consume)
 563                         status = git_inflate(&stream, 0);
 564                 else {
 565                         do {
 566                                 status = git_inflate(&stream, 0);
 567                                 if (consume(data, stream.next_out - data, cb_data)) {
 568                                         free(inbuf);
 569                                         free(data);
 570                                         return NULL;
 571                                 }
 572                                 stream.next_out = data;
 573                                 stream.avail_out = 64*1024;
 574                         } while (status == Z_OK && stream.avail_in);
 575                 }
 576         } while (len && status == Z_OK && !stream.avail_in);
 577
 578         /* This has been inflated OK when first encountered, so... */
 579         if (status != Z_STREAM_END || stream.total_out != obj->size)
 580                 die(_("serious inflate inconsistency"));
 581
 582         git_inflate_end(&stream);
 583         free(inbuf);
 584         if (consume) {
 585                 FREE_AND_NULL(data);
 586         }
 587         return data;
 588 }
 589
 590 static void *get_data_from_pack(struct object_entry *obj)
 591 {
 592         return unpack_data(obj, NULL, NULL);
 593 }
 594
 595 static int compare_ofs_delta_bases(off_t offset1, off_t offset2,
 596                                    enum object_type type1,
 597                                    enum object_type type2)
 598 {
 599         int cmp = type1 - type2;
 600         if (cmp)
 601                 return cmp;
 602         return offset1 < offset2 ? -1 :
 603                offset1 > offset2 ?  1 :
 604                0;
 605 }
 606
 607 static int find_ofs_delta(const off_t offset, enum object_type type)
 608 {
 609         int first = 0, last = nr_ofs_deltas;
 610
 611         while (first < last) {
 612                 int next = first + (last - first) / 2;
 613                 struct ofs_delta_entry *delta = &ofs_deltas[next];
 614                 int cmp;
 615
 616                 cmp = compare_ofs_delta_bases(offset, delta->offset,
 617                                               type, objects[delta->obj_no].type);
 618                 if (!cmp)
 619                         return next;
 620                 if (cmp < 0) {
 621                         last = next;
 622                         continue;
 623                 }
 624                 first = next+1;
 625         }
 626         return -first-1;
 627 }
 628
 629 static void find_ofs_delta_children(off_t offset,
 630                                     int *first_index, int *last_index,
 631                                     enum object_type type)
 632 {
 633         int first = find_ofs_delta(offset, type);
 634         int last = first;
 635         int end = nr_ofs_deltas - 1;
 636
 637         if (first < 0) {
 638                 *first_index = 0;
 639                 *last_index = -1;
 640                 return;
 641         }
 642         while (first > 0 && ofs_deltas[first - 1].offset == offset)
 643                 --first;
 644         while (last < end && ofs_deltas[last + 1].offset == offset)
 645                 ++last;
 646         *first_index = first;
 647         *last_index = last;
 648 }
 649
 650 static int compare_ref_delta_bases(const struct object_id *oid1,
 651                                    const struct object_id *oid2,
 652                                    enum object_type type1,
 653                                    enum object_type type2)
 654 {
 655         int cmp = type1 - type2;
 656         if (cmp)
 657                 return cmp;
 658         return oidcmp(oid1, oid2);
 659 }
 660
 661 static int find_ref_delta(const struct object_id *oid, enum object_type type)
 662 {
 663         int first = 0, last = nr_ref_deltas;
 664
 665         while (first < last) {
 666                 int next = first + (last - first) / 2;
 667                 struct ref_delta_entry *delta = &ref_deltas[next];
 668                 int cmp;
 669
 670                 cmp = compare_ref_delta_bases(oid, &delta->oid,
 671                                               type, objects[delta->obj_no].type);
 672                 if (!cmp)
 673                         return next;
 674                 if (cmp < 0) {
 675                         last = next;
 676                         continue;
 677                 }
 678                 first = next+1;
 679         }
 680         return -first-1;
 681 }
 682
 683 static void find_ref_delta_children(const struct object_id *oid,
 684                                     int *first_index, int *last_index,
 685                                     enum object_type type)
 686 {
 687         int first = find_ref_delta(oid, type);
 688         int last = first;
 689         int end = nr_ref_deltas - 1;
 690
 691         if (first < 0) {
 692                 *first_index = 0;
 693                 *last_index = -1;
 694                 return;
 695         }
 696         while (first > 0 && oideq(&ref_deltas[first - 1].oid, oid))
 697                 --first;
 698         while (last < end && oideq(&ref_deltas[last + 1].oid, oid))
 699                 ++last;
 700         *first_index = first;
 701         *last_index = last;
 702 }
 703
 704 struct compare_data {
 705         struct object_entry *entry;
 706         struct git_istream *st;
 707         unsigned char *buf;
 708         unsigned long buf_size;
 709 };
 710
 711 static int compare_objects(const unsigned char *buf, unsigned long size,
 712                            void *cb_data)
 713 {
 714         struct compare_data *data = cb_data;
 715
 716         if (data->buf_size < size) {
 717                 free(data->buf);
 718                 data->buf = xmalloc(size);
 719                 data->buf_size = size;
 720         }
 721
 722         while (size) {
 723                 ssize_t len = read_istream(data->st, data->buf, size);
 724                 if (len == 0)
 725                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 726                             oid_to_hex(&data->entry->idx.oid));
 727                 if (len < 0)
 728                         die(_("unable to read %s"),
 729                             oid_to_hex(&data->entry->idx.oid));
 730                 if (memcmp(buf, data->buf, len))
 731                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 732                             oid_to_hex(&data->entry->idx.oid));
 733                 size -= len;
 734                 buf += len;
 735         }
 736         return 0;
 737 }
 738
 739 static int check_collison(struct object_entry *entry)
 740 {
 741         struct compare_data data;
 742         enum object_type type;
 743         unsigned long size;
 744
 745         if (entry->size <= big_file_threshold || entry->type != OBJ_BLOB)
 746                 return -1;
 747
 748         memset(&data, 0, sizeof(data));
 749         data.entry = entry;
 750         data.st = open_istream(&entry->idx.oid, &type, &size, NULL);
 751         if (!data.st)
 752                 return -1;
 753         if (size != entry->size || type != entry->type)
 754                 die(_("SHA1 COLLISION FOUND WITH %s !"),
 755                     oid_to_hex(&entry->idx.oid));
 756         unpack_data(entry, compare_objects, &data);
 757         close_istream(data.st);
 758         free(data.buf);
 759         return 0;
 760 }
 761
 762 static void sha1_object(const void *data, struct object_entry *obj_entry,
 763                         unsigned long size, enum object_type type,
 764                         const struct object_id *oid)
 765 {
 766         void *new_data = NULL;
 767         int collision_test_needed = 0;
 768
 769         assert(data || obj_entry);
 770
 771         if (startup_info->have_repository) {
 772                 read_lock();
 773                 collision_test_needed =
 774                         has_sha1_file_with_flags(oid->hash, OBJECT_INFO_QUICK);
 775                 read_unlock();
 776         }
 777
 778         if (collision_test_needed && !data) {
 779                 read_lock();
 780                 if (!check_collison(obj_entry))
 781                         collision_test_needed = 0;
 782                 read_unlock();
 783         }
 784         if (collision_test_needed) {
 785                 void *has_data;
 786                 enum object_type has_type;
 787                 unsigned long has_size;
 788                 read_lock();
 789                 has_type = oid_object_info(the_repository, oid, &has_size);
 790                 if (has_type < 0)
 791                         die(_("cannot read existing object info %s"), oid_to_hex(oid));
 792                 if (has_type != type || has_size != size)
 793                         die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
 794                 has_data = read_object_file(oid, &has_type, &has_size);
 795                 read_unlock();
 796                 if (!data)
 797                         data = new_data = get_data_from_pack(obj_entry);
 798                 if (!has_data)
 799                         die(_("cannot read existing object %s"), oid_to_hex(oid));
 800                 if (size != has_size || type != has_type ||
 801                     memcmp(data, has_data, size) != 0)
 802                         die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
 803                 free(has_data);
 804         }
 805
 806         if (strict || do_fsck_object) {
 807                 read_lock();
 808                 if (type == OBJ_BLOB) {
 809                         struct blob *blob = lookup_blob(the_repository, oid);
 810                         if (blob)
 811                                 blob->object.flags |= FLAG_CHECKED;
 812                         else
 813                                 die(_("invalid blob object %s"), oid_to_hex(oid));
 814                         if (do_fsck_object &&
 815                             fsck_object(&blob->object, (void *)data, size, &fsck_options))
 816                                 die(_("fsck error in packed object"));
 817                 } else {
 818                         struct object *obj;
 819                         int eaten;
 820                         void *buf = (void *) data;
 821
 822                         assert(data && "data can only be NULL for large _blobs_");
 823
 824                         /*
 825                          * we do not need to free the memory here, as the
 826                          * buf is deleted by the caller.
 827                          */
 828                         obj = parse_object_buffer(the_repository, oid, type,
 829                                                   size, buf,
 830                                                   &eaten);
 831                         if (!obj)
 832                                 die(_("invalid %s"), type_name(type));
 833                         if (do_fsck_object &&
 834                             fsck_object(obj, buf, size, &fsck_options))
 835                                 die(_("fsck error in packed object"));
 836                         if (strict && fsck_walk(obj, NULL, &fsck_options))
 837                                 die(_("Not all child objects of %s are reachable"), oid_to_hex(&obj->oid));
 838
 839                         if (obj->type == OBJ_TREE) {
 840                                 struct tree *item = (struct tree *) obj;
 841                                 item->buffer = NULL;
 842                                 obj->parsed = 0;
 843                         }
 844                         if (obj->type == OBJ_COMMIT) {
 845                                 struct commit *commit = (struct commit *) obj;
 846                                 if (detach_commit_buffer(commit, NULL) != data)
 847                                         BUG("parse_object_buffer transmogrified our buffer");
 848                         }
 849                         obj->flags |= FLAG_CHECKED;
 850                 }
 851                 read_unlock();
 852         }
 853
 854         free(new_data);
 855 }
 856
 857 /*
 858  * This function is part of find_unresolved_deltas(). There are two
 859  * walkers going in the opposite ways.
 860  *
 861  * The first one in find_unresolved_deltas() traverses down from
 862  * parent node to children, deflating nodes along the way. However,
 863  * memory for deflated nodes is limited by delta_base_cache_limit, so
 864  * at some point parent node's deflated content may be freed.
 865  *
 866  * The second walker is this function, which goes from current node up
 867  * to top parent if necessary to deflate the node. In normal
 868  * situation, its parent node would be already deflated, so it just
 869  * needs to apply delta.
 870  *
 871  * In the worst case scenario, parent node is no longer deflated because
 872  * we're running out of delta_base_cache_limit; we need to re-deflate
 873  * parents, possibly up to the top base.
 874  *
 875  * All deflated objects here are subject to be freed if we exceed
 876  * delta_base_cache_limit, just like in find_unresolved_deltas(), we
 877  * just need to make sure the last node is not freed.
 878  */
 879 static void *get_base_data(struct base_data *c)
 880 {
 881         if (!c->data) {
 882                 struct object_entry *obj = c->obj;
 883                 struct base_data **delta = NULL;
 884                 int delta_nr = 0, delta_alloc = 0;
 885
 886                 while (is_delta_type(c->obj->type) && !c->data) {
 887                         ALLOC_GROW(delta, delta_nr + 1, delta_alloc);
 888                         delta[delta_nr++] = c;
 889                         c = c->base;
 890                 }
 891                 if (!delta_nr) {
 892                         c->data = get_data_from_pack(obj);
 893                         c->size = obj->size;
 894                         get_thread_data()->base_cache_used += c->size;
 895                         prune_base_data(c);
 896                 }
 897                 for (; delta_nr > 0; delta_nr--) {
 898                         void *base, *raw;
 899                         c = delta[delta_nr - 1];
 900                         obj = c->obj;
 901                         base = get_base_data(c->base);
 902                         raw = get_data_from_pack(obj);
 903                         c->data = patch_delta(
 904                                 base, c->base->size,
 905                                 raw, obj->size,
 906                                 &c->size);
 907                         free(raw);
 908                         if (!c->data)
 909                                 bad_object(obj->idx.offset, _("failed to apply delta"));
 910                         get_thread_data()->base_cache_used += c->size;
 911                         prune_base_data(c);
 912                 }
 913                 free(delta);
 914         }
 915         return c->data;
 916 }
 917
 918 static void resolve_delta(struct object_entry *delta_obj,
 919                           struct base_data *base, struct base_data *result)
 920 {
 921         void *base_data, *delta_data;
 922
 923         if (show_stat) {
 924                 int i = delta_obj - objects;
 925                 int j = base->obj - objects;
 926                 obj_stat[i].delta_depth = obj_stat[j].delta_depth + 1;
 927                 deepest_delta_lock();
 928                 if (deepest_delta < obj_stat[i].delta_depth)
 929                         deepest_delta = obj_stat[i].delta_depth;
 930                 deepest_delta_unlock();
 931                 obj_stat[i].base_object_no = j;
 932         }
 933         delta_data = get_data_from_pack(delta_obj);
 934         base_data = get_base_data(base);
 935         result->obj = delta_obj;
 936         result->data = patch_delta(base_data, base->size,
 937                                    delta_data, delta_obj->size, &result->size);
 938         free(delta_data);
 939         if (!result->data)
 940                 bad_object(delta_obj->idx.offset, _("failed to apply delta"));
 941         hash_object_file(result->data, result->size,
 942                          type_name(delta_obj->real_type), &delta_obj->idx.oid);
 943         sha1_object(result->data, NULL, result->size, delta_obj->real_type,
 944                     &delta_obj->idx.oid);
 945         counter_lock();
 946         nr_resolved_deltas++;
 947         counter_unlock();
 948 }
 949
 950 /*
 951  * Standard boolean compare-and-swap: atomically check whether "*type" is
 952  * "want"; if so, swap in "set" and return true. Otherwise, leave it untouched
 953  * and return false.
 954  */
 955 static int compare_and_swap_type(signed char *type,
 956                                  enum object_type want,
 957                                  enum object_type set)
 958 {
 959         enum object_type old;
 960
 961         type_cas_lock();
 962         old = *type;
 963         if (old == want)
 964                 *type = set;
 965         type_cas_unlock();
 966
 967         return old == want;
 968 }
 969
 970 static struct base_data *find_unresolved_deltas_1(struct base_data *base,
 971                                                   struct base_data *prev_base)
 972 {
 973         if (base->ref_last == -1 && base->ofs_last == -1) {
 974                 find_ref_delta_children(&base->obj->idx.oid,
 975                                         &base->ref_first, &base->ref_last,
 976                                         OBJ_REF_DELTA);
 977
 978                 find_ofs_delta_children(base->obj->idx.offset,
 979                                         &base->ofs_first, &base->ofs_last,
 980                                         OBJ_OFS_DELTA);
 981
 982                 if (base->ref_last == -1 && base->ofs_last == -1) {
 983                         free(base->data);
 984                         return NULL;
 985                 }
 986
 987                 link_base_data(prev_base, base);
 988         }
 989
 990         if (base->ref_first <= base->ref_last) {
 991                 struct object_entry *child = objects + ref_deltas[base->ref_first].obj_no;
 992                 struct base_data *result = alloc_base_data();
 993
 994                 if (!compare_and_swap_type(&child->real_type, OBJ_REF_DELTA,
 995                                            base->obj->real_type))
 996                         BUG("child->real_type != OBJ_REF_DELTA");
 997
 998                 resolve_delta(child, base, result);
 999                 if (base->ref_first == base->ref_last && base->ofs_last == -1)
1000                         free_base_data(base);
1001
1002                 base->ref_first++;
1003                 return result;
1004         }
1005
1006         if (base->ofs_first <= base->ofs_last) {
1007                 struct object_entry *child = objects + ofs_deltas[base->ofs_first].obj_no;
1008                 struct base_data *result = alloc_base_data();
1009
1010                 assert(child->real_type == OBJ_OFS_DELTA);
1011                 child->real_type = base->obj->real_type;
1012                 resolve_delta(child, base, result);
1013                 if (base->ofs_first == base->ofs_last)
1014                         free_base_data(base);
1015
1016                 base->ofs_first++;
1017                 return result;
1018         }
1019
1020         unlink_base_data(base);
1021         return NULL;
1022 }
1023
1024 static void find_unresolved_deltas(struct base_data *base)
1025 {
1026         struct base_data *new_base, *prev_base = NULL;
1027         for (;;) {
1028                 new_base = find_unresolved_deltas_1(base, prev_base);
1029
1030                 if (new_base) {
1031                         prev_base = base;
1032                         base = new_base;
1033                 } else {
1034                         free(base);
1035                         base = prev_base;
1036                         if (!base)
1037                                 return;
1038                         prev_base = base->base;
1039                 }
1040         }
1041 }
1042
1043 static int compare_ofs_delta_entry(const void *a, const void *b)
1044 {
1045         const struct ofs_delta_entry *delta_a = a;
1046         const struct ofs_delta_entry *delta_b = b;
1047
1048         return delta_a->offset < delta_b->offset ? -1 :
1049                delta_a->offset > delta_b->offset ?  1 :
1050                0;
1051 }
1052
1053 static int compare_ref_delta_entry(const void *a, const void *b)
1054 {
1055         const struct ref_delta_entry *delta_a = a;
1056         const struct ref_delta_entry *delta_b = b;
1057
1058         return oidcmp(&delta_a->oid, &delta_b->oid);
1059 }
1060
1061 static void resolve_base(struct object_entry *obj)
1062 {
1063         struct base_data *base_obj = alloc_base_data();
1064         base_obj->obj = obj;
1065         base_obj->data = NULL;
1066         find_unresolved_deltas(base_obj);
1067 }
1068
1069 static void *threaded_second_pass(void *data)
1070 {
1071         set_thread_data(data);
1072         for (;;) {
1073                 int i;
1074                 counter_lock();
1075                 display_progress(progress, nr_resolved_deltas);
1076                 counter_unlock();
1077                 work_lock();
1078                 while (nr_dispatched < nr_objects &&
1079                        is_delta_type(objects[nr_dispatched].type))
1080                         nr_dispatched++;
1081                 if (nr_dispatched >= nr_objects) {
1082                         work_unlock();
1083                         break;
1084                 }
1085                 i = nr_dispatched++;
1086                 work_unlock();
1087
1088                 resolve_base(&objects[i]);
1089         }
1090         return NULL;
1091 }
1092
1093 /*
1094  * First pass:
1095  * - find locations of all objects;
1096  * - calculate SHA1 of all non-delta objects;
1097  * - remember base (SHA1 or offset) for all deltas.
1098  */
1099 static void parse_pack_objects(unsigned char *hash)
1100 {
1101         int i, nr_delays = 0;
1102         struct ofs_delta_entry *ofs_delta = ofs_deltas;
1103         struct object_id ref_delta_oid;
1104         struct stat st;
1105
1106         if (verbose)
1107                 progress = start_progress(
1108                                 from_stdin ? _("Receiving objects") : _("Indexing objects"),
1109                                 nr_objects);
1110         for (i = 0; i < nr_objects; i++) {
1111                 struct object_entry *obj = &objects[i];
1112                 void *data = unpack_raw_entry(obj, &ofs_delta->offset,
1113                                               &ref_delta_oid,
1114                                               &obj->idx.oid);
1115                 obj->real_type = obj->type;
1116                 if (obj->type == OBJ_OFS_DELTA) {
1117                         nr_ofs_deltas++;
1118                         ofs_delta->obj_no = i;
1119                         ofs_delta++;
1120                 } else if (obj->type == OBJ_REF_DELTA) {
1121                         ALLOC_GROW(ref_deltas, nr_ref_deltas + 1, ref_deltas_alloc);
1122                         oidcpy(&ref_deltas[nr_ref_deltas].oid, &ref_delta_oid);
1123                         ref_deltas[nr_ref_deltas].obj_no = i;
1124                         nr_ref_deltas++;
1125                 } else if (!data) {
1126                         /* large blobs, check later */
1127                         obj->real_type = OBJ_BAD;
1128                         nr_delays++;
1129                 } else
1130                         sha1_object(data, NULL, obj->size, obj->type,
1131                                     &obj->idx.oid);
1132                 free(data);
1133                 display_progress(progress, i+1);
1134         }
1135         objects[i].idx.offset = consumed_bytes;
1136         stop_progress(&progress);
1137
1138         /* Check pack integrity */
1139         flush();
1140         the_hash_algo->final_fn(hash, &input_ctx);
1141         if (!hasheq(fill(the_hash_algo->rawsz), hash))
1142                 die(_("pack is corrupted (SHA1 mismatch)"));
1143         use(the_hash_algo->rawsz);
1144
1145         /* If input_fd is a file, we should have reached its end now. */
1146         if (fstat(input_fd, &st))
1147                 die_errno(_("cannot fstat packfile"));
1148         if (S_ISREG(st.st_mode) &&
1149                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
1150                 die(_("pack has junk at the end"));
1151
1152         for (i = 0; i < nr_objects; i++) {
1153                 struct object_entry *obj = &objects[i];
1154                 if (obj->real_type != OBJ_BAD)
1155                         continue;
1156                 obj->real_type = obj->type;
1157                 sha1_object(NULL, obj, obj->size, obj->type,
1158                             &obj->idx.oid);
1159                 nr_delays--;
1160         }
1161         if (nr_delays)
1162                 die(_("confusion beyond insanity in parse_pack_objects()"));
1163 }
1164
1165 /*
1166  * Second pass:
1167  * - for all non-delta objects, look if it is used as a base for
1168  *   deltas;
1169  * - if used as a base, uncompress the object and apply all deltas,
1170  *   recursively checking if the resulting object is used as a base
1171  *   for some more deltas.
1172  */
1173 static void resolve_deltas(void)
1174 {
1175         int i;
1176
1177         if (!nr_ofs_deltas && !nr_ref_deltas)
1178                 return;
1179
1180         /* Sort deltas by base SHA1/offset for fast searching */
1181         QSORT(ofs_deltas, nr_ofs_deltas, compare_ofs_delta_entry);
1182         QSORT(ref_deltas, nr_ref_deltas, compare_ref_delta_entry);
1183
1184         if (verbose || show_resolving_progress)
1185                 progress = start_progress(_("Resolving deltas"),
1186                                           nr_ref_deltas + nr_ofs_deltas);
1187
1188         nr_dispatched = 0;
1189         if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) {
1190                 init_thread();
1191                 for (i = 0; i < nr_threads; i++) {
1192                         int ret = pthread_create(&thread_data[i].thread, NULL,
1193                                                  threaded_second_pass, thread_data + i);
1194                         if (ret)
1195                                 die(_("unable to create thread: %s"),
1196                                     strerror(ret));
1197                 }
1198                 for (i = 0; i < nr_threads; i++)
1199                         pthread_join(thread_data[i].thread, NULL);
1200                 cleanup_thread();
1201                 return;
1202         }
1203
1204         for (i = 0; i < nr_objects; i++) {
1205                 struct object_entry *obj = &objects[i];
1206
1207                 if (is_delta_type(obj->type))
1208                         continue;
1209                 resolve_base(obj);
1210                 display_progress(progress, nr_resolved_deltas);
1211         }
1212 }
1213
1214 /*
1215  * Third pass:
1216  * - append objects to convert thin pack to full pack if required
1217  * - write the final pack hash
1218  */
1219 static void fix_unresolved_deltas(struct hashfile *f);
1220 static void conclude_pack(int fix_thin_pack, const char *curr_pack, unsigned char *pack_hash)
1221 {
1222         if (nr_ref_deltas + nr_ofs_deltas == nr_resolved_deltas) {
1223                 stop_progress(&progress);
1224                 /* Flush remaining pack final hash. */
1225                 flush();
1226                 return;
1227         }
1228
1229         if (fix_thin_pack) {
1230                 struct hashfile *f;
1231                 unsigned char read_hash[GIT_MAX_RAWSZ], tail_hash[GIT_MAX_RAWSZ];
1232                 struct strbuf msg = STRBUF_INIT;
1233                 int nr_unresolved = nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas;
1234                 int nr_objects_initial = nr_objects;
1235                 if (nr_unresolved <= 0)
1236                         die(_("confusion beyond insanity"));
1237                 REALLOC_ARRAY(objects, nr_objects + nr_unresolved + 1);
1238                 memset(objects + nr_objects + 1, 0,
1239                        nr_unresolved * sizeof(*objects));
1240                 f = hashfd(output_fd, curr_pack);
1241                 fix_unresolved_deltas(f);
1242                 strbuf_addf(&msg, Q_("completed with %d local object",
1243                                      "completed with %d local objects",
1244                                      nr_objects - nr_objects_initial),
1245                             nr_objects - nr_objects_initial);
1246                 stop_progress_msg(&progress, msg.buf);
1247                 strbuf_release(&msg);
1248                 finalize_hashfile(f, tail_hash, 0);
1249                 hashcpy(read_hash, pack_hash);
1250                 fixup_pack_header_footer(output_fd, pack_hash,
1251                                          curr_pack, nr_objects,
1252                                          read_hash, consumed_bytes-the_hash_algo->rawsz);
1253                 if (!hasheq(read_hash, tail_hash))
1254                         die(_("Unexpected tail checksum for %s "
1255                               "(disk corruption?)"), curr_pack);
1256         }
1257         if (nr_ofs_deltas + nr_ref_deltas != nr_resolved_deltas)
1258                 die(Q_("pack has %d unresolved delta",
1259                        "pack has %d unresolved deltas",
1260                        nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas),
1261                     nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas);
1262 }
1263
1264 static int write_compressed(struct hashfile *f, void *in, unsigned int size)
1265 {
1266         git_zstream stream;
1267         int status;
1268         unsigned char outbuf[4096];
1269
1270         git_deflate_init(&stream, zlib_compression_level);
1271         stream.next_in = in;
1272         stream.avail_in = size;
1273
1274         do {
1275                 stream.next_out = outbuf;
1276                 stream.avail_out = sizeof(outbuf);
1277                 status = git_deflate(&stream, Z_FINISH);
1278                 hashwrite(f, outbuf, sizeof(outbuf) - stream.avail_out);
1279         } while (status == Z_OK);
1280
1281         if (status != Z_STREAM_END)
1282                 die(_("unable to deflate appended object (%d)"), status);
1283         size = stream.total_out;
1284         git_deflate_end(&stream);
1285         return size;
1286 }
1287
1288 static struct object_entry *append_obj_to_pack(struct hashfile *f,
1289                                const unsigned char *sha1, void *buf,
1290                                unsigned long size, enum object_type type)
1291 {
1292         struct object_entry *obj = &objects[nr_objects++];
1293         unsigned char header[10];
1294         unsigned long s = size;
1295         int n = 0;
1296         unsigned char c = (type << 4) | (s & 15);
1297         s >>= 4;
1298         while (s) {
1299                 header[n++] = c | 0x80;
1300                 c = s & 0x7f;
1301                 s >>= 7;
1302         }
1303         header[n++] = c;
1304         crc32_begin(f);
1305         hashwrite(f, header, n);
1306         obj[0].size = size;
1307         obj[0].hdr_size = n;
1308         obj[0].type = type;
1309         obj[0].real_type = type;
1310         obj[1].idx.offset = obj[0].idx.offset + n;
1311         obj[1].idx.offset += write_compressed(f, buf, size);
1312         obj[0].idx.crc32 = crc32_end(f);
1313         hashflush(f);
1314         hashcpy(obj->idx.oid.hash, sha1);
1315         return obj;
1316 }
1317
1318 static int delta_pos_compare(const void *_a, const void *_b)
1319 {
1320         struct ref_delta_entry *a = *(struct ref_delta_entry **)_a;
1321         struct ref_delta_entry *b = *(struct ref_delta_entry **)_b;
1322         return a->obj_no - b->obj_no;
1323 }
1324
1325 static void fix_unresolved_deltas(struct hashfile *f)
1326 {
1327         struct ref_delta_entry **sorted_by_pos;
1328         int i;
1329
1330         /*
1331          * Since many unresolved deltas may well be themselves base objects
1332          * for more unresolved deltas, we really want to include the
1333          * smallest number of base objects that would cover as much delta
1334          * as possible by picking the
1335          * trunc deltas first, allowing for other deltas to resolve without
1336          * additional base objects.  Since most base objects are to be found
1337          * before deltas depending on them, a good heuristic is to start
1338          * resolving deltas in the same order as their position in the pack.
1339          */
1340         ALLOC_ARRAY(sorted_by_pos, nr_ref_deltas);
1341         for (i = 0; i < nr_ref_deltas; i++)
1342                 sorted_by_pos[i] = &ref_deltas[i];
1343         QSORT(sorted_by_pos, nr_ref_deltas, delta_pos_compare);
1344
1345         for (i = 0; i < nr_ref_deltas; i++) {
1346                 struct ref_delta_entry *d = sorted_by_pos[i];
1347                 enum object_type type;
1348                 struct base_data *base_obj = alloc_base_data();
1349
1350                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
1351                         continue;
1352                 base_obj->data = read_object_file(&d->oid, &type,
1353                                                   &base_obj->size);
1354                 if (!base_obj->data)
1355                         continue;
1356
1357                 if (check_object_signature(&d->oid, base_obj->data,
1358                                 base_obj->size, type_name(type)))
1359                         die(_("local object %s is corrupt"), oid_to_hex(&d->oid));
1360                 base_obj->obj = append_obj_to_pack(f, d->oid.hash,
1361                                         base_obj->data, base_obj->size, type);
1362                 find_unresolved_deltas(base_obj);
1363                 display_progress(progress, nr_resolved_deltas);
1364         }
1365         free(sorted_by_pos);
1366 }
1367
1368 static const char *derive_filename(const char *pack_name, const char *suffix,
1369                                    struct strbuf *buf)
1370 {
1371         size_t len;
1372         if (!strip_suffix(pack_name, ".pack", &len))
1373                 die(_("packfile name '%s' does not end with '.pack'"),
1374                     pack_name);
1375         strbuf_add(buf, pack_name, len);
1376         strbuf_addch(buf, '.');
1377         strbuf_addstr(buf, suffix);
1378         return buf->buf;
1379 }
1380
1381 static void write_special_file(const char *suffix, const char *msg,
1382                                const char *pack_name, const unsigned char *hash,
1383                                const char **report)
1384 {
1385         struct strbuf name_buf = STRBUF_INIT;
1386         const char *filename;
1387         int fd;
1388         int msg_len = strlen(msg);
1389
1390         if (pack_name)
1391                 filename = derive_filename(pack_name, suffix, &name_buf);
1392         else
1393                 filename = odb_pack_name(&name_buf, hash, suffix);
1394
1395         fd = odb_pack_keep(filename);
1396         if (fd < 0) {
1397                 if (errno != EEXIST)
1398                         die_errno(_("cannot write %s file '%s'"),
1399                                   suffix, filename);
1400         } else {
1401                 if (msg_len > 0) {
1402                         write_or_die(fd, msg, msg_len);
1403                         write_or_die(fd, "\n", 1);
1404                 }
1405                 if (close(fd) != 0)
1406                         die_errno(_("cannot close written %s file '%s'"),
1407                                   suffix, filename);
1408                 if (report)
1409                         *report = suffix;
1410         }
1411         strbuf_release(&name_buf);
1412 }
1413
1414 static void final(const char *final_pack_name, const char *curr_pack_name,
1415                   const char *final_index_name, const char *curr_index_name,
1416                   const char *keep_msg, const char *promisor_msg,
1417                   unsigned char *hash)
1418 {
1419         const char *report = "pack";
1420         struct strbuf pack_name = STRBUF_INIT;
1421         struct strbuf index_name = STRBUF_INIT;
1422         int err;
1423
1424         if (!from_stdin) {
1425                 close(input_fd);
1426         } else {
1427                 fsync_or_die(output_fd, curr_pack_name);
1428                 err = close(output_fd);
1429                 if (err)
1430                         die_errno(_("error while closing pack file"));
1431         }
1432
1433         if (keep_msg)
1434                 write_special_file("keep", keep_msg, final_pack_name, hash,
1435                                    &report);
1436         if (promisor_msg)
1437                 write_special_file("promisor", promisor_msg, final_pack_name,
1438                                    hash, NULL);
1439
1440         if (final_pack_name != curr_pack_name) {
1441                 if (!final_pack_name)
1442                         final_pack_name = odb_pack_name(&pack_name, hash, "pack");
1443                 if (finalize_object_file(curr_pack_name, final_pack_name))
1444                         die(_("cannot store pack file"));
1445         } else if (from_stdin)
1446                 chmod(final_pack_name, 0444);
1447
1448         if (final_index_name != curr_index_name) {
1449                 if (!final_index_name)
1450                         final_index_name = odb_pack_name(&index_name, hash, "idx");
1451                 if (finalize_object_file(curr_index_name, final_index_name))
1452                         die(_("cannot store index file"));
1453         } else
1454                 chmod(final_index_name, 0444);
1455
1456         if (do_fsck_object) {
1457                 struct packed_git *p;
1458                 p = add_packed_git(final_index_name, strlen(final_index_name), 0);
1459                 if (p)
1460                         install_packed_git(the_repository, p);
1461         }
1462
1463         if (!from_stdin) {
1464                 printf("%s\n", sha1_to_hex(hash));
1465         } else {
1466                 struct strbuf buf = STRBUF_INIT;
1467
1468                 strbuf_addf(&buf, "%s\t%s\n", report, sha1_to_hex(hash));
1469                 write_or_die(1, buf.buf, buf.len);
1470                 strbuf_release(&buf);
1471
1472                 /*
1473                  * Let's just mimic git-unpack-objects here and write
1474                  * the last part of the input buffer to stdout.
1475                  */
1476                 while (input_len) {
1477                         err = xwrite(1, input_buffer + input_offset, input_len);
1478                         if (err <= 0)
1479                                 break;
1480                         input_len -= err;
1481                         input_offset += err;
1482                 }
1483         }
1484
1485         strbuf_release(&index_name);
1486         strbuf_release(&pack_name);
1487 }
1488
1489 static int git_index_pack_config(const char *k, const char *v, void *cb)
1490 {
1491         struct pack_idx_option *opts = cb;
1492
1493         if (!strcmp(k, "pack.indexversion")) {
1494                 opts->version = git_config_int(k, v);
1495                 if (opts->version > 2)
1496                         die(_("bad pack.indexversion=%"PRIu32), opts->version);
1497                 return 0;
1498         }
1499         if (!strcmp(k, "pack.threads")) {
1500                 nr_threads = git_config_int(k, v);
1501                 if (nr_threads < 0)
1502                         die(_("invalid number of threads specified (%d)"),
1503                             nr_threads);
1504                 if (!HAVE_THREADS && nr_threads != 1) {
1505                         warning(_("no threads support, ignoring %s"), k);
1506                         nr_threads = 1;
1507                 }
1508                 return 0;
1509         }
1510         return git_default_config(k, v, cb);
1511 }
1512
1513 static int cmp_uint32(const void *a_, const void *b_)
1514 {
1515         uint32_t a = *((uint32_t *)a_);
1516         uint32_t b = *((uint32_t *)b_);
1517
1518         return (a < b) ? -1 : (a != b);
1519 }
1520
1521 static void read_v2_anomalous_offsets(struct packed_git *p,
1522                                       struct pack_idx_option *opts)
1523 {
1524         const uint32_t *idx1, *idx2;
1525         uint32_t i;
1526         const uint32_t hashwords = the_hash_algo->rawsz / sizeof(uint32_t);
1527
1528         /* The address of the 4-byte offset table */
1529         idx1 = (((const uint32_t *)p->index_data)
1530                 + 2 /* 8-byte header */
1531                 + 256 /* fan out */
1532                 + hashwords * p->num_objects /* object ID table */
1533                 + p->num_objects /* CRC32 table */
1534                 );
1535
1536         /* The address of the 8-byte offset table */
1537         idx2 = idx1 + p->num_objects;
1538
1539         for (i = 0; i < p->num_objects; i++) {
1540                 uint32_t off = ntohl(idx1[i]);
1541                 if (!(off & 0x80000000))
1542                         continue;
1543                 off = off & 0x7fffffff;
1544                 check_pack_index_ptr(p, &idx2[off * 2]);
1545                 if (idx2[off * 2])
1546                         continue;
1547                 /*
1548                  * The real offset is ntohl(idx2[off * 2]) in high 4
1549                  * octets, and ntohl(idx2[off * 2 + 1]) in low 4
1550                  * octets.  But idx2[off * 2] is Zero!!!
1551                  */
1552                 ALLOC_GROW(opts->anomaly, opts->anomaly_nr + 1, opts->anomaly_alloc);
1553                 opts->anomaly[opts->anomaly_nr++] = ntohl(idx2[off * 2 + 1]);
1554         }
1555
1556         QSORT(opts->anomaly, opts->anomaly_nr, cmp_uint32);
1557 }
1558
1559 static void read_idx_option(struct pack_idx_option *opts, const char *pack_name)
1560 {
1561         struct packed_git *p = add_packed_git(pack_name, strlen(pack_name), 1);
1562
1563         if (!p)
1564                 die(_("Cannot open existing pack file '%s'"), pack_name);
1565         if (open_pack_index(p))
1566                 die(_("Cannot open existing pack idx file for '%s'"), pack_name);
1567
1568         /* Read the attributes from the existing idx file */
1569         opts->version = p->index_version;
1570
1571         if (opts->version == 2)
1572                 read_v2_anomalous_offsets(p, opts);
1573
1574         /*
1575          * Get rid of the idx file as we do not need it anymore.
1576          * NEEDSWORK: extract this bit from free_pack_by_name() in
1577          * sha1-file.c, perhaps?  It shouldn't matter very much as we
1578          * know we haven't installed this pack (hence we never have
1579          * read anything from it).
1580          */
1581         close_pack_index(p);
1582         free(p);
1583 }
1584
1585 static void show_pack_info(int stat_only)
1586 {
1587         int i, baseobjects = nr_objects - nr_ref_deltas - nr_ofs_deltas;
1588         unsigned long *chain_histogram = NULL;
1589
1590         if (deepest_delta)
1591                 chain_histogram = xcalloc(deepest_delta, sizeof(unsigned long));
1592
1593         for (i = 0; i < nr_objects; i++) {
1594                 struct object_entry *obj = &objects[i];
1595
1596                 if (is_delta_type(obj->type))
1597                         chain_histogram[obj_stat[i].delta_depth - 1]++;
1598                 if (stat_only)
1599                         continue;
1600                 printf("%s %-6s %lu %lu %"PRIuMAX,
1601                        oid_to_hex(&obj->idx.oid),
1602                        type_name(obj->real_type), obj->size,
1603                        (unsigned long)(obj[1].idx.offset - obj->idx.offset),
1604                        (uintmax_t)obj->idx.offset);
1605                 if (is_delta_type(obj->type)) {
1606                         struct object_entry *bobj = &objects[obj_stat[i].base_object_no];
1607                         printf(" %u %s", obj_stat[i].delta_depth,
1608                                oid_to_hex(&bobj->idx.oid));
1609                 }
1610                 putchar('\n');
1611         }
1612
1613         if (baseobjects)
1614                 printf_ln(Q_("non delta: %d object",
1615                              "non delta: %d objects",
1616                              baseobjects),
1617                           baseobjects);
1618         for (i = 0; i < deepest_delta; i++) {
1619                 if (!chain_histogram[i])
1620                         continue;
1621                 printf_ln(Q_("chain length = %d: %lu object",
1622                              "chain length = %d: %lu objects",
1623                              chain_histogram[i]),
1624                           i + 1,
1625                           chain_histogram[i]);
1626         }
1627 }
1628
1629 int cmd_index_pack(int argc, const char **argv, const char *prefix)
1630 {
1631         int i, fix_thin_pack = 0, verify = 0, stat_only = 0;
1632         const char *curr_index;
1633         const char *index_name = NULL, *pack_name = NULL;
1634         const char *keep_msg = NULL;
1635         const char *promisor_msg = NULL;
1636         struct strbuf index_name_buf = STRBUF_INIT;
1637         struct pack_idx_entry **idx_objects;
1638         struct pack_idx_option opts;
1639         unsigned char pack_hash[GIT_MAX_RAWSZ];
1640         unsigned foreign_nr = 1;        /* zero is a "good" value, assume bad */
1641         int report_end_of_input = 0;
1642
1643         /*
1644          * index-pack never needs to fetch missing objects, since it only
1645          * accesses the repo to do hash collision checks
1646          */
1647         fetch_if_missing = 0;
1648
1649         if (argc == 2 && !strcmp(argv[1], "-h"))
1650                 usage(index_pack_usage);
1651
1652         read_replace_refs = 0;
1653         fsck_options.walk = mark_link;
1654
1655         reset_pack_idx_option(&opts);
1656         git_config(git_index_pack_config, &opts);
1657         if (prefix && chdir(prefix))
1658                 die(_("Cannot come back to cwd"));
1659
1660         for (i = 1; i < argc; i++) {
1661                 const char *arg = argv[i];
1662
1663                 if (*arg == '-') {
1664                         if (!strcmp(arg, "--stdin")) {
1665                                 from_stdin = 1;
1666                         } else if (!strcmp(arg, "--fix-thin")) {
1667                                 fix_thin_pack = 1;
1668                         } else if (skip_to_optional_arg(arg, "--strict", &arg)) {
1669                                 strict = 1;
1670                                 do_fsck_object = 1;
1671                                 fsck_set_msg_types(&fsck_options, arg);
1672                         } else if (!strcmp(arg, "--check-self-contained-and-connected")) {
1673                                 strict = 1;
1674                                 check_self_contained_and_connected = 1;
1675                         } else if (!strcmp(arg, "--fsck-objects")) {
1676                                 do_fsck_object = 1;
1677                         } else if (!strcmp(arg, "--verify")) {
1678                                 verify = 1;
1679                         } else if (!strcmp(arg, "--verify-stat")) {
1680                                 verify = 1;
1681                                 show_stat = 1;
1682                         } else if (!strcmp(arg, "--verify-stat-only")) {
1683                                 verify = 1;
1684                                 show_stat = 1;
1685                                 stat_only = 1;
1686                         } else if (skip_to_optional_arg(arg, "--keep", &keep_msg)) {
1687                                 ; /* nothing to do */
1688                         } else if (skip_to_optional_arg(arg, "--promisor", &promisor_msg)) {
1689                                 ; /* already parsed */
1690                         } else if (starts_with(arg, "--threads=")) {
1691                                 char *end;
1692                                 nr_threads = strtoul(arg+10, &end, 0);
1693                                 if (!arg[10] || *end || nr_threads < 0)
1694                                         usage(index_pack_usage);
1695                                 if (!HAVE_THREADS && nr_threads != 1) {
1696                                         warning(_("no threads support, ignoring %s"), arg);
1697                                         nr_threads = 1;
1698                                 }
1699                         } else if (starts_with(arg, "--pack_header=")) {
1700                                 struct pack_header *hdr;
1701                                 char *c;
1702
1703                                 hdr = (struct pack_header *)input_buffer;
1704                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
1705                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
1706                                 if (*c != ',')
1707                                         die(_("bad %s"), arg);
1708                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
1709                                 if (*c)
1710                                         die(_("bad %s"), arg);
1711                                 input_len = sizeof(*hdr);
1712                         } else if (!strcmp(arg, "-v")) {
1713                                 verbose = 1;
1714                         } else if (!strcmp(arg, "--show-resolving-progress")) {
1715                                 show_resolving_progress = 1;
1716                         } else if (!strcmp(arg, "--report-end-of-input")) {
1717                                 report_end_of_input = 1;
1718                         } else if (!strcmp(arg, "-o")) {
1719                                 if (index_name || (i+1) >= argc)
1720                                         usage(index_pack_usage);
1721                                 index_name = argv[++i];
1722                         } else if (starts_with(arg, "--index-version=")) {
1723                                 char *c;
1724                                 opts.version = strtoul(arg + 16, &c, 10);
1725                                 if (opts.version > 2)
1726                                         die(_("bad %s"), arg);
1727                                 if (*c == ',')
1728                                         opts.off32_limit = strtoul(c+1, &c, 0);
1729                                 if (*c || opts.off32_limit & 0x80000000)
1730                                         die(_("bad %s"), arg);
1731                         } else if (skip_prefix(arg, "--max-input-size=", &arg)) {
1732                                 max_input_size = strtoumax(arg, NULL, 10);
1733                         } else
1734                                 usage(index_pack_usage);
1735                         continue;
1736                 }
1737
1738                 if (pack_name)
1739                         usage(index_pack_usage);
1740                 pack_name = arg;
1741         }
1742
1743         if (!pack_name && !from_stdin)
1744                 usage(index_pack_usage);
1745         if (fix_thin_pack && !from_stdin)
1746                 die(_("--fix-thin cannot be used without --stdin"));
1747         if (from_stdin && !startup_info->have_repository)
1748                 die(_("--stdin requires a git repository"));
1749         if (!index_name && pack_name)
1750                 index_name = derive_filename(pack_name, "idx", &index_name_buf);
1751
1752         if (verify) {
1753                 if (!index_name)
1754                         die(_("--verify with no packfile name given"));
1755                 read_idx_option(&opts, index_name);
1756                 opts.flags |= WRITE_IDX_VERIFY | WRITE_IDX_STRICT;
1757         }
1758         if (strict)
1759                 opts.flags |= WRITE_IDX_STRICT;
1760
1761         if (HAVE_THREADS && !nr_threads) {
1762                 nr_threads = online_cpus();
1763                 /* An experiment showed that more threads does not mean faster */
1764                 if (nr_threads > 3)
1765                         nr_threads = 3;
1766         }
1767
1768         curr_pack = open_pack_file(pack_name);
1769         parse_pack_header();
1770         objects = xcalloc(st_add(nr_objects, 1), sizeof(struct object_entry));
1771         if (show_stat)
1772                 obj_stat = xcalloc(st_add(nr_objects, 1), sizeof(struct object_stat));
1773         ofs_deltas = xcalloc(nr_objects, sizeof(struct ofs_delta_entry));
1774         parse_pack_objects(pack_hash);
1775         if (report_end_of_input)
1776                 write_in_full(2, "\0", 1);
1777         resolve_deltas();
1778         conclude_pack(fix_thin_pack, curr_pack, pack_hash);
1779         free(ofs_deltas);
1780         free(ref_deltas);
1781         if (strict)
1782                 foreign_nr = check_objects();
1783
1784         if (show_stat)
1785                 show_pack_info(stat_only);
1786
1787         ALLOC_ARRAY(idx_objects, nr_objects);
1788         for (i = 0; i < nr_objects; i++)
1789                 idx_objects[i] = &objects[i].idx;
1790         curr_index = write_idx_file(index_name, idx_objects, nr_objects, &opts, pack_hash);
1791         free(idx_objects);
1792
1793         if (!verify)
1794                 final(pack_name, curr_pack,
1795                       index_name, curr_index,
1796                       keep_msg, promisor_msg,
1797                       pack_hash);
1798         else
1799                 close(input_fd);
1800
1801         if (do_fsck_object && fsck_finish(&fsck_options))
1802                 die(_("fsck error in pack objects"));
1803
1804         free(objects);
1805         strbuf_release(&index_name_buf);
1806         if (pack_name == NULL)
1807                 free((void *) curr_pack);
1808         if (index_name == NULL)
1809                 free((void *) curr_index);
1810
1811         /*
1812          * Let the caller know this pack is not self contained
1813          */
1814         if (check_self_contained_and_connected && foreign_nr)
1815                 return 1;
1816
1817         return 0;
1818 }