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

   1 #include "builtin.h"
   2 #include "delta.h"
   3 #include "pack.h"
   4 #include "csum-file.h"
   5 #include "blob.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "tree.h"
   9 #include "progress.h"
  10 #include "fsck.h"
  11 #include "exec_cmd.h"
  12 #include "streaming.h"
  13 #include "thread-utils.h"
  14
  15 static const char index_pack_usage[] =
  16 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
  17
  18 struct object_entry {
  19         struct pack_idx_entry idx;
  20         unsigned long size;
  21         unsigned char hdr_size;
  22         signed char type;
  23         signed char real_type;
  24 };
  25
  26 struct object_stat {
  27         unsigned delta_depth;
  28         int base_object_no;
  29 };
  30
  31 struct base_data {
  32         struct base_data *base;
  33         struct base_data *child;
  34         struct object_entry *obj;
  35         void *data;
  36         unsigned long size;
  37         int ref_first, ref_last;
  38         int ofs_first, ofs_last;
  39 };
  40
  41 struct thread_local {
  42 #ifndef NO_PTHREADS
  43         pthread_t thread;
  44 #endif
  45         struct base_data *base_cache;
  46         size_t base_cache_used;
  47         int pack_fd;
  48 };
  49
  50 #define FLAG_LINK (1u<<20)
  51 #define FLAG_CHECKED (1u<<21)
  52
  53 struct ofs_delta_entry {
  54         off_t offset;
  55         int obj_no;
  56 };
  57
  58 struct ref_delta_entry {
  59         unsigned char sha1[20];
  60         int obj_no;
  61 };
  62
  63 static struct object_entry *objects;
  64 static struct object_stat *obj_stat;
  65 static struct ofs_delta_entry *ofs_deltas;
  66 static struct ref_delta_entry *ref_deltas;
  67 static struct thread_local nothread_data;
  68 static int nr_objects;
  69 static int nr_ofs_deltas;
  70 static int nr_ref_deltas;
  71 static int ref_deltas_alloc;
  72 static int nr_resolved_deltas;
  73 static int nr_threads;
  74
  75 static int from_stdin;
  76 static int strict;
  77 static int do_fsck_object;
  78 static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
  79 static int verbose;
  80 static int show_resolving_progress;
  81 static int show_stat;
  82 static int check_self_contained_and_connected;
  83
  84 static struct progress *progress;
  85
  86 /* We always read in 4kB chunks. */
  87 static unsigned char input_buffer[4096];
  88 static unsigned int input_offset, input_len;
  89 static off_t consumed_bytes;
  90 static off_t max_input_size;
  91 static unsigned deepest_delta;
  92 static git_SHA_CTX input_ctx;
  93 static uint32_t input_crc32;
  94 static int input_fd, output_fd;
  95 static const char *curr_pack;
  96
  97 #ifndef NO_PTHREADS
  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 #else
 179
 180 #define read_lock()
 181 #define read_unlock()
 182
 183 #define counter_lock()
 184 #define counter_unlock()
 185
 186 #define work_lock()
 187 #define work_unlock()
 188
 189 #define deepest_delta_lock()
 190 #define deepest_delta_unlock()
 191
 192 #define type_cas_lock()
 193 #define type_cas_unlock()
 194
 195 #endif
 196
 197
 198 static int mark_link(struct object *obj, int type, void *data, struct fsck_options *options)
 199 {
 200         if (!obj)
 201                 return -1;
 202
 203         if (type != OBJ_ANY && obj->type != type)
 204                 die(_("object type mismatch at %s"), oid_to_hex(&obj->oid));
 205
 206         obj->flags |= FLAG_LINK;
 207         return 0;
 208 }
 209
 210 /* The content of each linked object must have been checked
 211    or it must be already present in the object database */
 212 static unsigned check_object(struct object *obj)
 213 {
 214         if (!obj)
 215                 return 0;
 216
 217         if (!(obj->flags & FLAG_LINK))
 218                 return 0;
 219
 220         if (!(obj->flags & FLAG_CHECKED)) {
 221                 unsigned long size;
 222                 int type = sha1_object_info(obj->oid.hash, &size);
 223                 if (type <= 0)
 224                         die(_("did not receive expected object %s"),
 225                               oid_to_hex(&obj->oid));
 226                 if (type != obj->type)
 227                         die(_("object %s: expected type %s, found %s"),
 228                             oid_to_hex(&obj->oid),
 229                             typename(obj->type), typename(type));
 230                 obj->flags |= FLAG_CHECKED;
 231                 return 1;
 232         }
 233
 234         return 0;
 235 }
 236
 237 static unsigned check_objects(void)
 238 {
 239         unsigned i, max, foreign_nr = 0;
 240
 241         max = get_max_object_index();
 242         for (i = 0; i < max; i++)
 243                 foreign_nr += check_object(get_indexed_object(i));
 244         return foreign_nr;
 245 }
 246
 247
 248 /* Discard current buffer used content. */
 249 static void flush(void)
 250 {
 251         if (input_offset) {
 252                 if (output_fd >= 0)
 253                         write_or_die(output_fd, input_buffer, input_offset);
 254                 git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 255                 memmove(input_buffer, input_buffer + input_offset, input_len);
 256                 input_offset = 0;
 257         }
 258 }
 259
 260 /*
 261  * Make sure at least "min" bytes are available in the buffer, and
 262  * return the pointer to the buffer.
 263  */
 264 static void *fill(int min)
 265 {
 266         if (min <= input_len)
 267                 return input_buffer + input_offset;
 268         if (min > sizeof(input_buffer))
 269                 die(Q_("cannot fill %d byte",
 270                        "cannot fill %d bytes",
 271                        min),
 272                     min);
 273         flush();
 274         do {
 275                 ssize_t ret = xread(input_fd, input_buffer + input_len,
 276                                 sizeof(input_buffer) - input_len);
 277                 if (ret <= 0) {
 278                         if (!ret)
 279                                 die(_("early EOF"));
 280                         die_errno(_("read error on input"));
 281                 }
 282                 input_len += ret;
 283                 if (from_stdin)
 284                         display_throughput(progress, consumed_bytes + input_len);
 285         } while (input_len < min);
 286         return input_buffer;
 287 }
 288
 289 static void use(int bytes)
 290 {
 291         if (bytes > input_len)
 292                 die(_("used more bytes than were available"));
 293         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 294         input_len -= bytes;
 295         input_offset += bytes;
 296
 297         /* make sure off_t is sufficiently large not to wrap */
 298         if (signed_add_overflows(consumed_bytes, bytes))
 299                 die(_("pack too large for current definition of off_t"));
 300         consumed_bytes += bytes;
 301         if (max_input_size && consumed_bytes > max_input_size)
 302                 die(_("pack exceeds maximum allowed size"));
 303 }
 304
 305 static const char *open_pack_file(const char *pack_name)
 306 {
 307         if (from_stdin) {
 308                 input_fd = 0;
 309                 if (!pack_name) {
 310                         struct strbuf tmp_file = STRBUF_INIT;
 311                         output_fd = odb_mkstemp(&tmp_file,
 312                                                 "pack/tmp_pack_XXXXXX");
 313                         pack_name = strbuf_detach(&tmp_file, NULL);
 314                 } else {
 315                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 316                         if (output_fd < 0)
 317                                 die_errno(_("unable to create '%s'"), pack_name);
 318                 }
 319                 nothread_data.pack_fd = output_fd;
 320         } else {
 321                 input_fd = open(pack_name, O_RDONLY);
 322                 if (input_fd < 0)
 323                         die_errno(_("cannot open packfile '%s'"), pack_name);
 324                 output_fd = -1;
 325                 nothread_data.pack_fd = input_fd;
 326         }
 327         git_SHA1_Init(&input_ctx);
 328         return pack_name;
 329 }
 330
 331 static void parse_pack_header(void)
 332 {
 333         struct pack_header *hdr = fill(sizeof(struct pack_header));
 334
 335         /* Header consistency check */
 336         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 337                 die(_("pack signature mismatch"));
 338         if (!pack_version_ok(hdr->hdr_version))
 339                 die(_("pack version %"PRIu32" unsupported"),
 340                         ntohl(hdr->hdr_version));
 341
 342         nr_objects = ntohl(hdr->hdr_entries);
 343         use(sizeof(struct pack_header));
 344 }
 345
 346 static NORETURN void bad_object(off_t offset, const char *format,
 347                        ...) __attribute__((format (printf, 2, 3)));
 348
 349 static NORETURN void bad_object(off_t offset, const char *format, ...)
 350 {
 351         va_list params;
 352         char buf[1024];
 353
 354         va_start(params, format);
 355         vsnprintf(buf, sizeof(buf), format, params);
 356         va_end(params);
 357         die(_("pack has bad object at offset %"PRIuMAX": %s"),
 358             (uintmax_t)offset, buf);
 359 }
 360
 361 static inline struct thread_local *get_thread_data(void)
 362 {
 363 #ifndef NO_PTHREADS
 364         if (threads_active)
 365                 return pthread_getspecific(key);
 366         assert(!threads_active &&
 367                "This should only be reached when all threads are gone");
 368 #endif
 369         return &nothread_data;
 370 }
 371
 372 #ifndef NO_PTHREADS
 373 static void set_thread_data(struct thread_local *data)
 374 {
 375         if (threads_active)
 376                 pthread_setspecific(key, data);
 377 }
 378 #endif
 379
 380 static struct base_data *alloc_base_data(void)
 381 {
 382         struct base_data *base = xcalloc(1, sizeof(struct base_data));
 383         base->ref_last = -1;
 384         base->ofs_last = -1;
 385         return base;
 386 }
 387
 388 static void free_base_data(struct base_data *c)
 389 {
 390         if (c->data) {
 391                 free(c->data);
 392                 c->data = NULL;
 393                 get_thread_data()->base_cache_used -= c->size;
 394         }
 395 }
 396
 397 static void prune_base_data(struct base_data *retain)
 398 {
 399         struct base_data *b;
 400         struct thread_local *data = get_thread_data();
 401         for (b = data->base_cache;
 402              data->base_cache_used > delta_base_cache_limit && b;
 403              b = b->child) {
 404                 if (b->data && b != retain)
 405                         free_base_data(b);
 406         }
 407 }
 408
 409 static void link_base_data(struct base_data *base, struct base_data *c)
 410 {
 411         if (base)
 412                 base->child = c;
 413         else
 414                 get_thread_data()->base_cache = c;
 415
 416         c->base = base;
 417         c->child = NULL;
 418         if (c->data)
 419                 get_thread_data()->base_cache_used += c->size;
 420         prune_base_data(c);
 421 }
 422
 423 static void unlink_base_data(struct base_data *c)
 424 {
 425         struct base_data *base = c->base;
 426         if (base)
 427                 base->child = NULL;
 428         else
 429                 get_thread_data()->base_cache = NULL;
 430         free_base_data(c);
 431 }
 432
 433 static int is_delta_type(enum object_type type)
 434 {
 435         return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
 436 }
 437
 438 static void *unpack_entry_data(off_t offset, unsigned long size,
 439                                enum object_type type, unsigned char *sha1)
 440 {
 441         static char fixed_buf[8192];
 442         int status;
 443         git_zstream stream;
 444         void *buf;
 445         git_SHA_CTX c;
 446         char hdr[32];
 447         int hdrlen;
 448
 449         if (!is_delta_type(type)) {
 450                 hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), size) + 1;
 451                 git_SHA1_Init(&c);
 452                 git_SHA1_Update(&c, hdr, hdrlen);
 453         } else
 454                 sha1 = NULL;
 455         if (type == OBJ_BLOB && size > big_file_threshold)
 456                 buf = fixed_buf;
 457         else
 458                 buf = xmallocz(size);
 459
 460         memset(&stream, 0, sizeof(stream));
 461         git_inflate_init(&stream);
 462         stream.next_out = buf;
 463         stream.avail_out = buf == fixed_buf ? sizeof(fixed_buf) : size;
 464
 465         do {
 466                 unsigned char *last_out = stream.next_out;
 467                 stream.next_in = fill(1);
 468                 stream.avail_in = input_len;
 469                 status = git_inflate(&stream, 0);
 470                 use(input_len - stream.avail_in);
 471                 if (sha1)
 472                         git_SHA1_Update(&c, last_out, stream.next_out - last_out);
 473                 if (buf == fixed_buf) {
 474                         stream.next_out = buf;
 475                         stream.avail_out = sizeof(fixed_buf);
 476                 }
 477         } while (status == Z_OK);
 478         if (stream.total_out != size || status != Z_STREAM_END)
 479                 bad_object(offset, _("inflate returned %d"), status);
 480         git_inflate_end(&stream);
 481         if (sha1)
 482                 git_SHA1_Final(sha1, &c);
 483         return buf == fixed_buf ? NULL : buf;
 484 }
 485
 486 static void *unpack_raw_entry(struct object_entry *obj,
 487                               off_t *ofs_offset,
 488                               unsigned char *ref_sha1,
 489                               unsigned char *sha1)
 490 {
 491         unsigned char *p;
 492         unsigned long size, c;
 493         off_t base_offset;
 494         unsigned shift;
 495         void *data;
 496
 497         obj->idx.offset = consumed_bytes;
 498         input_crc32 = crc32(0, NULL, 0);
 499
 500         p = fill(1);
 501         c = *p;
 502         use(1);
 503         obj->type = (c >> 4) & 7;
 504         size = (c & 15);
 505         shift = 4;
 506         while (c & 0x80) {
 507                 p = fill(1);
 508                 c = *p;
 509                 use(1);
 510                 size += (c & 0x7f) << shift;
 511                 shift += 7;
 512         }
 513         obj->size = size;
 514
 515         switch (obj->type) {
 516         case OBJ_REF_DELTA:
 517                 hashcpy(ref_sha1, fill(20));
 518                 use(20);
 519                 break;
 520         case OBJ_OFS_DELTA:
 521                 p = fill(1);
 522                 c = *p;
 523                 use(1);
 524                 base_offset = c & 127;
 525                 while (c & 128) {
 526                         base_offset += 1;
 527                         if (!base_offset || MSB(base_offset, 7))
 528                                 bad_object(obj->idx.offset, _("offset value overflow for delta base object"));
 529                         p = fill(1);
 530                         c = *p;
 531                         use(1);
 532                         base_offset = (base_offset << 7) + (c & 127);
 533                 }
 534                 *ofs_offset = obj->idx.offset - base_offset;
 535                 if (*ofs_offset <= 0 || *ofs_offset >= obj->idx.offset)
 536                         bad_object(obj->idx.offset, _("delta base offset is out of bound"));
 537                 break;
 538         case OBJ_COMMIT:
 539         case OBJ_TREE:
 540         case OBJ_BLOB:
 541         case OBJ_TAG:
 542                 break;
 543         default:
 544                 bad_object(obj->idx.offset, _("unknown object type %d"), obj->type);
 545         }
 546         obj->hdr_size = consumed_bytes - obj->idx.offset;
 547
 548         data = unpack_entry_data(obj->idx.offset, obj->size, obj->type, sha1);
 549         obj->idx.crc32 = input_crc32;
 550         return data;
 551 }
 552
 553 static void *unpack_data(struct object_entry *obj,
 554                          int (*consume)(const unsigned char *, unsigned long, void *),
 555                          void *cb_data)
 556 {
 557         off_t from = obj[0].idx.offset + obj[0].hdr_size;
 558         off_t len = obj[1].idx.offset - from;
 559         unsigned char *data, *inbuf;
 560         git_zstream stream;
 561         int status;
 562
 563         data = xmallocz(consume ? 64*1024 : obj->size);
 564         inbuf = xmalloc((len < 64*1024) ? (int)len : 64*1024);
 565
 566         memset(&stream, 0, sizeof(stream));
 567         git_inflate_init(&stream);
 568         stream.next_out = data;
 569         stream.avail_out = consume ? 64*1024 : obj->size;
 570
 571         do {
 572                 ssize_t n = (len < 64*1024) ? (ssize_t)len : 64*1024;
 573                 n = xpread(get_thread_data()->pack_fd, inbuf, n, from);
 574                 if (n < 0)
 575                         die_errno(_("cannot pread pack file"));
 576                 if (!n)
 577                         die(Q_("premature end of pack file, %"PRIuMAX" byte missing",
 578                                "premature end of pack file, %"PRIuMAX" bytes missing",
 579                                (unsigned int)len),
 580                             (uintmax_t)len);
 581                 from += n;
 582                 len -= n;
 583                 stream.next_in = inbuf;
 584                 stream.avail_in = n;
 585                 if (!consume)
 586                         status = git_inflate(&stream, 0);
 587                 else {
 588                         do {
 589                                 status = git_inflate(&stream, 0);
 590                                 if (consume(data, stream.next_out - data, cb_data)) {
 591                                         free(inbuf);
 592                                         free(data);
 593                                         return NULL;
 594                                 }
 595                                 stream.next_out = data;
 596                                 stream.avail_out = 64*1024;
 597                         } while (status == Z_OK && stream.avail_in);
 598                 }
 599         } while (len && status == Z_OK && !stream.avail_in);
 600
 601         /* This has been inflated OK when first encountered, so... */
 602         if (status != Z_STREAM_END || stream.total_out != obj->size)
 603                 die(_("serious inflate inconsistency"));
 604
 605         git_inflate_end(&stream);
 606         free(inbuf);
 607         if (consume) {
 608                 free(data);
 609                 data = NULL;
 610         }
 611         return data;
 612 }
 613
 614 static void *get_data_from_pack(struct object_entry *obj)
 615 {
 616         return unpack_data(obj, NULL, NULL);
 617 }
 618
 619 static int compare_ofs_delta_bases(off_t offset1, off_t offset2,
 620                                    enum object_type type1,
 621                                    enum object_type type2)
 622 {
 623         int cmp = type1 - type2;
 624         if (cmp)
 625                 return cmp;
 626         return offset1 < offset2 ? -1 :
 627                offset1 > offset2 ?  1 :
 628                0;
 629 }
 630
 631 static int find_ofs_delta(const off_t offset, enum object_type type)
 632 {
 633         int first = 0, last = nr_ofs_deltas;
 634
 635         while (first < last) {
 636                 int next = (first + last) / 2;
 637                 struct ofs_delta_entry *delta = &ofs_deltas[next];
 638                 int cmp;
 639
 640                 cmp = compare_ofs_delta_bases(offset, delta->offset,
 641                                               type, objects[delta->obj_no].type);
 642                 if (!cmp)
 643                         return next;
 644                 if (cmp < 0) {
 645                         last = next;
 646                         continue;
 647                 }
 648                 first = next+1;
 649         }
 650         return -first-1;
 651 }
 652
 653 static void find_ofs_delta_children(off_t offset,
 654                                     int *first_index, int *last_index,
 655                                     enum object_type type)
 656 {
 657         int first = find_ofs_delta(offset, type);
 658         int last = first;
 659         int end = nr_ofs_deltas - 1;
 660
 661         if (first < 0) {
 662                 *first_index = 0;
 663                 *last_index = -1;
 664                 return;
 665         }
 666         while (first > 0 && ofs_deltas[first - 1].offset == offset)
 667                 --first;
 668         while (last < end && ofs_deltas[last + 1].offset == offset)
 669                 ++last;
 670         *first_index = first;
 671         *last_index = last;
 672 }
 673
 674 static int compare_ref_delta_bases(const unsigned char *sha1,
 675                                    const unsigned char *sha2,
 676                                    enum object_type type1,
 677                                    enum object_type type2)
 678 {
 679         int cmp = type1 - type2;
 680         if (cmp)
 681                 return cmp;
 682         return hashcmp(sha1, sha2);
 683 }
 684
 685 static int find_ref_delta(const unsigned char *sha1, enum object_type type)
 686 {
 687         int first = 0, last = nr_ref_deltas;
 688
 689         while (first < last) {
 690                 int next = (first + last) / 2;
 691                 struct ref_delta_entry *delta = &ref_deltas[next];
 692                 int cmp;
 693
 694                 cmp = compare_ref_delta_bases(sha1, delta->sha1,
 695                                               type, objects[delta->obj_no].type);
 696                 if (!cmp)
 697                         return next;
 698                 if (cmp < 0) {
 699                         last = next;
 700                         continue;
 701                 }
 702                 first = next+1;
 703         }
 704         return -first-1;
 705 }
 706
 707 static void find_ref_delta_children(const unsigned char *sha1,
 708                                     int *first_index, int *last_index,
 709                                     enum object_type type)
 710 {
 711         int first = find_ref_delta(sha1, type);
 712         int last = first;
 713         int end = nr_ref_deltas - 1;
 714
 715         if (first < 0) {
 716                 *first_index = 0;
 717                 *last_index = -1;
 718                 return;
 719         }
 720         while (first > 0 && !hashcmp(ref_deltas[first - 1].sha1, sha1))
 721                 --first;
 722         while (last < end && !hashcmp(ref_deltas[last + 1].sha1, sha1))
 723                 ++last;
 724         *first_index = first;
 725         *last_index = last;
 726 }
 727
 728 struct compare_data {
 729         struct object_entry *entry;
 730         struct git_istream *st;
 731         unsigned char *buf;
 732         unsigned long buf_size;
 733 };
 734
 735 static int compare_objects(const unsigned char *buf, unsigned long size,
 736                            void *cb_data)
 737 {
 738         struct compare_data *data = cb_data;
 739
 740         if (data->buf_size < size) {
 741                 free(data->buf);
 742                 data->buf = xmalloc(size);
 743                 data->buf_size = size;
 744         }
 745
 746         while (size) {
 747                 ssize_t len = read_istream(data->st, data->buf, size);
 748                 if (len == 0)
 749                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 750                             sha1_to_hex(data->entry->idx.sha1));
 751                 if (len < 0)
 752                         die(_("unable to read %s"),
 753                             sha1_to_hex(data->entry->idx.sha1));
 754                 if (memcmp(buf, data->buf, len))
 755                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 756                             sha1_to_hex(data->entry->idx.sha1));
 757                 size -= len;
 758                 buf += len;
 759         }
 760         return 0;
 761 }
 762
 763 static int check_collison(struct object_entry *entry)
 764 {
 765         struct compare_data data;
 766         enum object_type type;
 767         unsigned long size;
 768
 769         if (entry->size <= big_file_threshold || entry->type != OBJ_BLOB)
 770                 return -1;
 771
 772         memset(&data, 0, sizeof(data));
 773         data.entry = entry;
 774         data.st = open_istream(entry->idx.sha1, &type, &size, NULL);
 775         if (!data.st)
 776                 return -1;
 777         if (size != entry->size || type != entry->type)
 778                 die(_("SHA1 COLLISION FOUND WITH %s !"),
 779                     sha1_to_hex(entry->idx.sha1));
 780         unpack_data(entry, compare_objects, &data);
 781         close_istream(data.st);
 782         free(data.buf);
 783         return 0;
 784 }
 785
 786 static void sha1_object(const void *data, struct object_entry *obj_entry,
 787                         unsigned long size, enum object_type type,
 788                         const unsigned char *sha1)
 789 {
 790         void *new_data = NULL;
 791         int collision_test_needed = 0;
 792
 793         assert(data || obj_entry);
 794
 795         if (startup_info->have_repository) {
 796                 read_lock();
 797                 collision_test_needed = has_sha1_file_with_flags(sha1, HAS_SHA1_QUICK);
 798                 read_unlock();
 799         }
 800
 801         if (collision_test_needed && !data) {
 802                 read_lock();
 803                 if (!check_collison(obj_entry))
 804                         collision_test_needed = 0;
 805                 read_unlock();
 806         }
 807         if (collision_test_needed) {
 808                 void *has_data;
 809                 enum object_type has_type;
 810                 unsigned long has_size;
 811                 read_lock();
 812                 has_type = sha1_object_info(sha1, &has_size);
 813                 if (has_type < 0)
 814                         die(_("cannot read existing object info %s"), sha1_to_hex(sha1));
 815                 if (has_type != type || has_size != size)
 816                         die(_("SHA1 COLLISION FOUND WITH %s !"), sha1_to_hex(sha1));
 817                 has_data = read_sha1_file(sha1, &has_type, &has_size);
 818                 read_unlock();
 819                 if (!data)
 820                         data = new_data = get_data_from_pack(obj_entry);
 821                 if (!has_data)
 822                         die(_("cannot read existing object %s"), sha1_to_hex(sha1));
 823                 if (size != has_size || type != has_type ||
 824                     memcmp(data, has_data, size) != 0)
 825                         die(_("SHA1 COLLISION FOUND WITH %s !"), sha1_to_hex(sha1));
 826                 free(has_data);
 827         }
 828
 829         if (strict) {
 830                 read_lock();
 831                 if (type == OBJ_BLOB) {
 832                         struct blob *blob = lookup_blob(sha1);
 833                         if (blob)
 834                                 blob->object.flags |= FLAG_CHECKED;
 835                         else
 836                                 die(_("invalid blob object %s"), sha1_to_hex(sha1));
 837                 } else {
 838                         struct object *obj;
 839                         int eaten;
 840                         void *buf = (void *) data;
 841
 842                         assert(data && "data can only be NULL for large _blobs_");
 843
 844                         /*
 845                          * we do not need to free the memory here, as the
 846                          * buf is deleted by the caller.
 847                          */
 848                         obj = parse_object_buffer(sha1, type, size, buf, &eaten);
 849                         if (!obj)
 850                                 die(_("invalid %s"), typename(type));
 851                         if (do_fsck_object &&
 852                             fsck_object(obj, buf, size, &fsck_options))
 853                                 die(_("Error in object"));
 854                         if (fsck_walk(obj, NULL, &fsck_options))
 855                                 die(_("Not all child objects of %s are reachable"), oid_to_hex(&obj->oid));
 856
 857                         if (obj->type == OBJ_TREE) {
 858                                 struct tree *item = (struct tree *) obj;
 859                                 item->buffer = NULL;
 860                                 obj->parsed = 0;
 861                         }
 862                         if (obj->type == OBJ_COMMIT) {
 863                                 struct commit *commit = (struct commit *) obj;
 864                                 if (detach_commit_buffer(commit, NULL) != data)
 865                                         die("BUG: parse_object_buffer transmogrified our buffer");
 866                         }
 867                         obj->flags |= FLAG_CHECKED;
 868                 }
 869                 read_unlock();
 870         }
 871
 872         free(new_data);
 873 }
 874
 875 /*
 876  * This function is part of find_unresolved_deltas(). There are two
 877  * walkers going in the opposite ways.
 878  *
 879  * The first one in find_unresolved_deltas() traverses down from
 880  * parent node to children, deflating nodes along the way. However,
 881  * memory for deflated nodes is limited by delta_base_cache_limit, so
 882  * at some point parent node's deflated content may be freed.
 883  *
 884  * The second walker is this function, which goes from current node up
 885  * to top parent if necessary to deflate the node. In normal
 886  * situation, its parent node would be already deflated, so it just
 887  * needs to apply delta.
 888  *
 889  * In the worst case scenario, parent node is no longer deflated because
 890  * we're running out of delta_base_cache_limit; we need to re-deflate
 891  * parents, possibly up to the top base.
 892  *
 893  * All deflated objects here are subject to be freed if we exceed
 894  * delta_base_cache_limit, just like in find_unresolved_deltas(), we
 895  * just need to make sure the last node is not freed.
 896  */
 897 static void *get_base_data(struct base_data *c)
 898 {
 899         if (!c->data) {
 900                 struct object_entry *obj = c->obj;
 901                 struct base_data **delta = NULL;
 902                 int delta_nr = 0, delta_alloc = 0;
 903
 904                 while (is_delta_type(c->obj->type) && !c->data) {
 905                         ALLOC_GROW(delta, delta_nr + 1, delta_alloc);
 906                         delta[delta_nr++] = c;
 907                         c = c->base;
 908                 }
 909                 if (!delta_nr) {
 910                         c->data = get_data_from_pack(obj);
 911                         c->size = obj->size;
 912                         get_thread_data()->base_cache_used += c->size;
 913                         prune_base_data(c);
 914                 }
 915                 for (; delta_nr > 0; delta_nr--) {
 916                         void *base, *raw;
 917                         c = delta[delta_nr - 1];
 918                         obj = c->obj;
 919                         base = get_base_data(c->base);
 920                         raw = get_data_from_pack(obj);
 921                         c->data = patch_delta(
 922                                 base, c->base->size,
 923                                 raw, obj->size,
 924                                 &c->size);
 925                         free(raw);
 926                         if (!c->data)
 927                                 bad_object(obj->idx.offset, _("failed to apply delta"));
 928                         get_thread_data()->base_cache_used += c->size;
 929                         prune_base_data(c);
 930                 }
 931                 free(delta);
 932         }
 933         return c->data;
 934 }
 935
 936 static void resolve_delta(struct object_entry *delta_obj,
 937                           struct base_data *base, struct base_data *result)
 938 {
 939         void *base_data, *delta_data;
 940
 941         if (show_stat) {
 942                 int i = delta_obj - objects;
 943                 int j = base->obj - objects;
 944                 obj_stat[i].delta_depth = obj_stat[j].delta_depth + 1;
 945                 deepest_delta_lock();
 946                 if (deepest_delta < obj_stat[i].delta_depth)
 947                         deepest_delta = obj_stat[i].delta_depth;
 948                 deepest_delta_unlock();
 949                 obj_stat[i].base_object_no = j;
 950         }
 951         delta_data = get_data_from_pack(delta_obj);
 952         base_data = get_base_data(base);
 953         result->obj = delta_obj;
 954         result->data = patch_delta(base_data, base->size,
 955                                    delta_data, delta_obj->size, &result->size);
 956         free(delta_data);
 957         if (!result->data)
 958                 bad_object(delta_obj->idx.offset, _("failed to apply delta"));
 959         hash_sha1_file(result->data, result->size,
 960                        typename(delta_obj->real_type), delta_obj->idx.sha1);
 961         sha1_object(result->data, NULL, result->size, delta_obj->real_type,
 962                     delta_obj->idx.sha1);
 963         counter_lock();
 964         nr_resolved_deltas++;
 965         counter_unlock();
 966 }
 967
 968 /*
 969  * Standard boolean compare-and-swap: atomically check whether "*type" is
 970  * "want"; if so, swap in "set" and return true. Otherwise, leave it untouched
 971  * and return false.
 972  */
 973 static int compare_and_swap_type(signed char *type,
 974                                  enum object_type want,
 975                                  enum object_type set)
 976 {
 977         enum object_type old;
 978
 979         type_cas_lock();
 980         old = *type;
 981         if (old == want)
 982                 *type = set;
 983         type_cas_unlock();
 984
 985         return old == want;
 986 }
 987
 988 static struct base_data *find_unresolved_deltas_1(struct base_data *base,
 989                                                   struct base_data *prev_base)
 990 {
 991         if (base->ref_last == -1 && base->ofs_last == -1) {
 992                 find_ref_delta_children(base->obj->idx.sha1,
 993                                         &base->ref_first, &base->ref_last,
 994                                         OBJ_REF_DELTA);
 995
 996                 find_ofs_delta_children(base->obj->idx.offset,
 997                                         &base->ofs_first, &base->ofs_last,
 998                                         OBJ_OFS_DELTA);
 999
1000                 if (base->ref_last == -1 && base->ofs_last == -1) {
1001                         free(base->data);
1002                         return NULL;
1003                 }
1004
1005                 link_base_data(prev_base, base);
1006         }
1007
1008         if (base->ref_first <= base->ref_last) {
1009                 struct object_entry *child = objects + ref_deltas[base->ref_first].obj_no;
1010                 struct base_data *result = alloc_base_data();
1011
1012                 if (!compare_and_swap_type(&child->real_type, OBJ_REF_DELTA,
1013                                            base->obj->real_type))
1014                         die("BUG: child->real_type != OBJ_REF_DELTA");
1015
1016                 resolve_delta(child, base, result);
1017                 if (base->ref_first == base->ref_last && base->ofs_last == -1)
1018                         free_base_data(base);
1019
1020                 base->ref_first++;
1021                 return result;
1022         }
1023
1024         if (base->ofs_first <= base->ofs_last) {
1025                 struct object_entry *child = objects + ofs_deltas[base->ofs_first].obj_no;
1026                 struct base_data *result = alloc_base_data();
1027
1028                 assert(child->real_type == OBJ_OFS_DELTA);
1029                 child->real_type = base->obj->real_type;
1030                 resolve_delta(child, base, result);
1031                 if (base->ofs_first == base->ofs_last)
1032                         free_base_data(base);
1033
1034                 base->ofs_first++;
1035                 return result;
1036         }
1037
1038         unlink_base_data(base);
1039         return NULL;
1040 }
1041
1042 static void find_unresolved_deltas(struct base_data *base)
1043 {
1044         struct base_data *new_base, *prev_base = NULL;
1045         for (;;) {
1046                 new_base = find_unresolved_deltas_1(base, prev_base);
1047
1048                 if (new_base) {
1049                         prev_base = base;
1050                         base = new_base;
1051                 } else {
1052                         free(base);
1053                         base = prev_base;
1054                         if (!base)
1055                                 return;
1056                         prev_base = base->base;
1057                 }
1058         }
1059 }
1060
1061 static int compare_ofs_delta_entry(const void *a, const void *b)
1062 {
1063         const struct ofs_delta_entry *delta_a = a;
1064         const struct ofs_delta_entry *delta_b = b;
1065
1066         return delta_a->offset < delta_b->offset ? -1 :
1067                delta_a->offset > delta_b->offset ?  1 :
1068                0;
1069 }
1070
1071 static int compare_ref_delta_entry(const void *a, const void *b)
1072 {
1073         const struct ref_delta_entry *delta_a = a;
1074         const struct ref_delta_entry *delta_b = b;
1075
1076         return hashcmp(delta_a->sha1, delta_b->sha1);
1077 }
1078
1079 static void resolve_base(struct object_entry *obj)
1080 {
1081         struct base_data *base_obj = alloc_base_data();
1082         base_obj->obj = obj;
1083         base_obj->data = NULL;
1084         find_unresolved_deltas(base_obj);
1085 }
1086
1087 #ifndef NO_PTHREADS
1088 static void *threaded_second_pass(void *data)
1089 {
1090         set_thread_data(data);
1091         for (;;) {
1092                 int i;
1093                 counter_lock();
1094                 display_progress(progress, nr_resolved_deltas);
1095                 counter_unlock();
1096                 work_lock();
1097                 while (nr_dispatched < nr_objects &&
1098                        is_delta_type(objects[nr_dispatched].type))
1099                         nr_dispatched++;
1100                 if (nr_dispatched >= nr_objects) {
1101                         work_unlock();
1102                         break;
1103                 }
1104                 i = nr_dispatched++;
1105                 work_unlock();
1106
1107                 resolve_base(&objects[i]);
1108         }
1109         return NULL;
1110 }
1111 #endif
1112
1113 /*
1114  * First pass:
1115  * - find locations of all objects;
1116  * - calculate SHA1 of all non-delta objects;
1117  * - remember base (SHA1 or offset) for all deltas.
1118  */
1119 static void parse_pack_objects(unsigned char *sha1)
1120 {
1121         int i, nr_delays = 0;
1122         struct ofs_delta_entry *ofs_delta = ofs_deltas;
1123         unsigned char ref_delta_sha1[20];
1124         struct stat st;
1125
1126         if (verbose)
1127                 progress = start_progress(
1128                                 from_stdin ? _("Receiving objects") : _("Indexing objects"),
1129                                 nr_objects);
1130         for (i = 0; i < nr_objects; i++) {
1131                 struct object_entry *obj = &objects[i];
1132                 void *data = unpack_raw_entry(obj, &ofs_delta->offset,
1133                                               ref_delta_sha1, obj->idx.sha1);
1134                 obj->real_type = obj->type;
1135                 if (obj->type == OBJ_OFS_DELTA) {
1136                         nr_ofs_deltas++;
1137                         ofs_delta->obj_no = i;
1138                         ofs_delta++;
1139                 } else if (obj->type == OBJ_REF_DELTA) {
1140                         ALLOC_GROW(ref_deltas, nr_ref_deltas + 1, ref_deltas_alloc);
1141                         hashcpy(ref_deltas[nr_ref_deltas].sha1, ref_delta_sha1);
1142                         ref_deltas[nr_ref_deltas].obj_no = i;
1143                         nr_ref_deltas++;
1144                 } else if (!data) {
1145                         /* large blobs, check later */
1146                         obj->real_type = OBJ_BAD;
1147                         nr_delays++;
1148                 } else
1149                         sha1_object(data, NULL, obj->size, obj->type, obj->idx.sha1);
1150                 free(data);
1151                 display_progress(progress, i+1);
1152         }
1153         objects[i].idx.offset = consumed_bytes;
1154         stop_progress(&progress);
1155
1156         /* Check pack integrity */
1157         flush();
1158         git_SHA1_Final(sha1, &input_ctx);
1159         if (hashcmp(fill(20), sha1))
1160                 die(_("pack is corrupted (SHA1 mismatch)"));
1161         use(20);
1162
1163         /* If input_fd is a file, we should have reached its end now. */
1164         if (fstat(input_fd, &st))
1165                 die_errno(_("cannot fstat packfile"));
1166         if (S_ISREG(st.st_mode) &&
1167                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
1168                 die(_("pack has junk at the end"));
1169
1170         for (i = 0; i < nr_objects; i++) {
1171                 struct object_entry *obj = &objects[i];
1172                 if (obj->real_type != OBJ_BAD)
1173                         continue;
1174                 obj->real_type = obj->type;
1175                 sha1_object(NULL, obj, obj->size, obj->type, obj->idx.sha1);
1176                 nr_delays--;
1177         }
1178         if (nr_delays)
1179                 die(_("confusion beyond insanity in parse_pack_objects()"));
1180 }
1181
1182 /*
1183  * Second pass:
1184  * - for all non-delta objects, look if it is used as a base for
1185  *   deltas;
1186  * - if used as a base, uncompress the object and apply all deltas,
1187  *   recursively checking if the resulting object is used as a base
1188  *   for some more deltas.
1189  */
1190 static void resolve_deltas(void)
1191 {
1192         int i;
1193
1194         if (!nr_ofs_deltas && !nr_ref_deltas)
1195                 return;
1196
1197         /* Sort deltas by base SHA1/offset for fast searching */
1198         QSORT(ofs_deltas, nr_ofs_deltas, compare_ofs_delta_entry);
1199         QSORT(ref_deltas, nr_ref_deltas, compare_ref_delta_entry);
1200
1201         if (verbose || show_resolving_progress)
1202                 progress = start_progress(_("Resolving deltas"),
1203                                           nr_ref_deltas + nr_ofs_deltas);
1204
1205 #ifndef NO_PTHREADS
1206         nr_dispatched = 0;
1207         if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) {
1208                 init_thread();
1209                 for (i = 0; i < nr_threads; i++) {
1210                         int ret = pthread_create(&thread_data[i].thread, NULL,
1211                                                  threaded_second_pass, thread_data + i);
1212                         if (ret)
1213                                 die(_("unable to create thread: %s"),
1214                                     strerror(ret));
1215                 }
1216                 for (i = 0; i < nr_threads; i++)
1217                         pthread_join(thread_data[i].thread, NULL);
1218                 cleanup_thread();
1219                 return;
1220         }
1221 #endif
1222
1223         for (i = 0; i < nr_objects; i++) {
1224                 struct object_entry *obj = &objects[i];
1225
1226                 if (is_delta_type(obj->type))
1227                         continue;
1228                 resolve_base(obj);
1229                 display_progress(progress, nr_resolved_deltas);
1230         }
1231 }
1232
1233 /*
1234  * Third pass:
1235  * - append objects to convert thin pack to full pack if required
1236  * - write the final 20-byte SHA-1
1237  */
1238 static void fix_unresolved_deltas(struct sha1file *f);
1239 static void conclude_pack(int fix_thin_pack, const char *curr_pack, unsigned char *pack_sha1)
1240 {
1241         if (nr_ref_deltas + nr_ofs_deltas == nr_resolved_deltas) {
1242                 stop_progress(&progress);
1243                 /* Flush remaining pack final 20-byte SHA1. */
1244                 flush();
1245                 return;
1246         }
1247
1248         if (fix_thin_pack) {
1249                 struct sha1file *f;
1250                 unsigned char read_sha1[20], tail_sha1[20];
1251                 struct strbuf msg = STRBUF_INIT;
1252                 int nr_unresolved = nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas;
1253                 int nr_objects_initial = nr_objects;
1254                 if (nr_unresolved <= 0)
1255                         die(_("confusion beyond insanity"));
1256                 REALLOC_ARRAY(objects, nr_objects + nr_unresolved + 1);
1257                 memset(objects + nr_objects + 1, 0,
1258                        nr_unresolved * sizeof(*objects));
1259                 f = sha1fd(output_fd, curr_pack);
1260                 fix_unresolved_deltas(f);
1261                 strbuf_addf(&msg, Q_("completed with %d local object",
1262                                      "completed with %d local objects",
1263                                      nr_objects - nr_objects_initial),
1264                             nr_objects - nr_objects_initial);
1265                 stop_progress_msg(&progress, msg.buf);
1266                 strbuf_release(&msg);
1267                 sha1close(f, tail_sha1, 0);
1268                 hashcpy(read_sha1, pack_sha1);
1269                 fixup_pack_header_footer(output_fd, pack_sha1,
1270                                          curr_pack, nr_objects,
1271                                          read_sha1, consumed_bytes-20);
1272                 if (hashcmp(read_sha1, tail_sha1) != 0)
1273                         die(_("Unexpected tail checksum for %s "
1274                               "(disk corruption?)"), curr_pack);
1275         }
1276         if (nr_ofs_deltas + nr_ref_deltas != nr_resolved_deltas)
1277                 die(Q_("pack has %d unresolved delta",
1278                        "pack has %d unresolved deltas",
1279                        nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas),
1280                     nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas);
1281 }
1282
1283 static int write_compressed(struct sha1file *f, void *in, unsigned int size)
1284 {
1285         git_zstream stream;
1286         int status;
1287         unsigned char outbuf[4096];
1288
1289         git_deflate_init(&stream, zlib_compression_level);
1290         stream.next_in = in;
1291         stream.avail_in = size;
1292
1293         do {
1294                 stream.next_out = outbuf;
1295                 stream.avail_out = sizeof(outbuf);
1296                 status = git_deflate(&stream, Z_FINISH);
1297                 sha1write(f, outbuf, sizeof(outbuf) - stream.avail_out);
1298         } while (status == Z_OK);
1299
1300         if (status != Z_STREAM_END)
1301                 die(_("unable to deflate appended object (%d)"), status);
1302         size = stream.total_out;
1303         git_deflate_end(&stream);
1304         return size;
1305 }
1306
1307 static struct object_entry *append_obj_to_pack(struct sha1file *f,
1308                                const unsigned char *sha1, void *buf,
1309                                unsigned long size, enum object_type type)
1310 {
1311         struct object_entry *obj = &objects[nr_objects++];
1312         unsigned char header[10];
1313         unsigned long s = size;
1314         int n = 0;
1315         unsigned char c = (type << 4) | (s & 15);
1316         s >>= 4;
1317         while (s) {
1318                 header[n++] = c | 0x80;
1319                 c = s & 0x7f;
1320                 s >>= 7;
1321         }
1322         header[n++] = c;
1323         crc32_begin(f);
1324         sha1write(f, header, n);
1325         obj[0].size = size;
1326         obj[0].hdr_size = n;
1327         obj[0].type = type;
1328         obj[0].real_type = type;
1329         obj[1].idx.offset = obj[0].idx.offset + n;
1330         obj[1].idx.offset += write_compressed(f, buf, size);
1331         obj[0].idx.crc32 = crc32_end(f);
1332         sha1flush(f);
1333         hashcpy(obj->idx.sha1, sha1);
1334         return obj;
1335 }
1336
1337 static int delta_pos_compare(const void *_a, const void *_b)
1338 {
1339         struct ref_delta_entry *a = *(struct ref_delta_entry **)_a;
1340         struct ref_delta_entry *b = *(struct ref_delta_entry **)_b;
1341         return a->obj_no - b->obj_no;
1342 }
1343
1344 static void fix_unresolved_deltas(struct sha1file *f)
1345 {
1346         struct ref_delta_entry **sorted_by_pos;
1347         int i;
1348
1349         /*
1350          * Since many unresolved deltas may well be themselves base objects
1351          * for more unresolved deltas, we really want to include the
1352          * smallest number of base objects that would cover as much delta
1353          * as possible by picking the
1354          * trunc deltas first, allowing for other deltas to resolve without
1355          * additional base objects.  Since most base objects are to be found
1356          * before deltas depending on them, a good heuristic is to start
1357          * resolving deltas in the same order as their position in the pack.
1358          */
1359         ALLOC_ARRAY(sorted_by_pos, nr_ref_deltas);
1360         for (i = 0; i < nr_ref_deltas; i++)
1361                 sorted_by_pos[i] = &ref_deltas[i];
1362         QSORT(sorted_by_pos, nr_ref_deltas, delta_pos_compare);
1363
1364         for (i = 0; i < nr_ref_deltas; i++) {
1365                 struct ref_delta_entry *d = sorted_by_pos[i];
1366                 enum object_type type;
1367                 struct base_data *base_obj = alloc_base_data();
1368
1369                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
1370                         continue;
1371                 base_obj->data = read_sha1_file(d->sha1, &type, &base_obj->size);
1372                 if (!base_obj->data)
1373                         continue;
1374
1375                 if (check_sha1_signature(d->sha1, base_obj->data,
1376                                 base_obj->size, typename(type)))
1377                         die(_("local object %s is corrupt"), sha1_to_hex(d->sha1));
1378                 base_obj->obj = append_obj_to_pack(f, d->sha1,
1379                                         base_obj->data, base_obj->size, type);
1380                 find_unresolved_deltas(base_obj);
1381                 display_progress(progress, nr_resolved_deltas);
1382         }
1383         free(sorted_by_pos);
1384 }
1385
1386 static void final(const char *final_pack_name, const char *curr_pack_name,
1387                   const char *final_index_name, const char *curr_index_name,
1388                   const char *keep_name, const char *keep_msg,
1389                   unsigned char *sha1)
1390 {
1391         const char *report = "pack";
1392         struct strbuf pack_name = STRBUF_INIT;
1393         struct strbuf index_name = STRBUF_INIT;
1394         struct strbuf keep_name_buf = STRBUF_INIT;
1395         int err;
1396
1397         if (!from_stdin) {
1398                 close(input_fd);
1399         } else {
1400                 fsync_or_die(output_fd, curr_pack_name);
1401                 err = close(output_fd);
1402                 if (err)
1403                         die_errno(_("error while closing pack file"));
1404         }
1405
1406         if (keep_msg) {
1407                 int keep_fd, keep_msg_len = strlen(keep_msg);
1408
1409                 if (!keep_name)
1410                         keep_name = odb_pack_name(&keep_name_buf, sha1, "keep");
1411
1412                 keep_fd = odb_pack_keep(keep_name);
1413                 if (keep_fd < 0) {
1414                         if (errno != EEXIST)
1415                                 die_errno(_("cannot write keep file '%s'"),
1416                                           keep_name);
1417                 } else {
1418                         if (keep_msg_len > 0) {
1419                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
1420                                 write_or_die(keep_fd, "\n", 1);
1421                         }
1422                         if (close(keep_fd) != 0)
1423                                 die_errno(_("cannot close written keep file '%s'"),
1424                                           keep_name);
1425                         report = "keep";
1426                 }
1427         }
1428
1429         if (final_pack_name != curr_pack_name) {
1430                 if (!final_pack_name)
1431                         final_pack_name = odb_pack_name(&pack_name, sha1, "pack");
1432                 if (finalize_object_file(curr_pack_name, final_pack_name))
1433                         die(_("cannot store pack file"));
1434         } else if (from_stdin)
1435                 chmod(final_pack_name, 0444);
1436
1437         if (final_index_name != curr_index_name) {
1438                 if (!final_index_name)
1439                         final_index_name = odb_pack_name(&index_name, sha1, "idx");
1440                 if (finalize_object_file(curr_index_name, final_index_name))
1441                         die(_("cannot store index file"));
1442         } else
1443                 chmod(final_index_name, 0444);
1444
1445         if (!from_stdin) {
1446                 printf("%s\n", sha1_to_hex(sha1));
1447         } else {
1448                 struct strbuf buf = STRBUF_INIT;
1449
1450                 strbuf_addf(&buf, "%s\t%s\n", report, sha1_to_hex(sha1));
1451                 write_or_die(1, buf.buf, buf.len);
1452                 strbuf_release(&buf);
1453
1454                 /*
1455                  * Let's just mimic git-unpack-objects here and write
1456                  * the last part of the input buffer to stdout.
1457                  */
1458                 while (input_len) {
1459                         err = xwrite(1, input_buffer + input_offset, input_len);
1460                         if (err <= 0)
1461                                 break;
1462                         input_len -= err;
1463                         input_offset += err;
1464                 }
1465         }
1466
1467         strbuf_release(&index_name);
1468         strbuf_release(&pack_name);
1469         strbuf_release(&keep_name_buf);
1470 }
1471
1472 static int git_index_pack_config(const char *k, const char *v, void *cb)
1473 {
1474         struct pack_idx_option *opts = cb;
1475
1476         if (!strcmp(k, "pack.indexversion")) {
1477                 opts->version = git_config_int(k, v);
1478                 if (opts->version > 2)
1479                         die(_("bad pack.indexversion=%"PRIu32), opts->version);
1480                 return 0;
1481         }
1482         if (!strcmp(k, "pack.threads")) {
1483                 nr_threads = git_config_int(k, v);
1484                 if (nr_threads < 0)
1485                         die(_("invalid number of threads specified (%d)"),
1486                             nr_threads);
1487 #ifdef NO_PTHREADS
1488                 if (nr_threads != 1)
1489                         warning(_("no threads support, ignoring %s"), k);
1490                 nr_threads = 1;
1491 #endif
1492                 return 0;
1493         }
1494         return git_default_config(k, v, cb);
1495 }
1496
1497 static int cmp_uint32(const void *a_, const void *b_)
1498 {
1499         uint32_t a = *((uint32_t *)a_);
1500         uint32_t b = *((uint32_t *)b_);
1501
1502         return (a < b) ? -1 : (a != b);
1503 }
1504
1505 static void read_v2_anomalous_offsets(struct packed_git *p,
1506                                       struct pack_idx_option *opts)
1507 {
1508         const uint32_t *idx1, *idx2;
1509         uint32_t i;
1510
1511         /* The address of the 4-byte offset table */
1512         idx1 = (((const uint32_t *)p->index_data)
1513                 + 2 /* 8-byte header */
1514                 + 256 /* fan out */
1515                 + 5 * p->num_objects /* 20-byte SHA-1 table */
1516                 + p->num_objects /* CRC32 table */
1517                 );
1518
1519         /* The address of the 8-byte offset table */
1520         idx2 = idx1 + p->num_objects;
1521
1522         for (i = 0; i < p->num_objects; i++) {
1523                 uint32_t off = ntohl(idx1[i]);
1524                 if (!(off & 0x80000000))
1525                         continue;
1526                 off = off & 0x7fffffff;
1527                 check_pack_index_ptr(p, &idx2[off * 2]);
1528                 if (idx2[off * 2])
1529                         continue;
1530                 /*
1531                  * The real offset is ntohl(idx2[off * 2]) in high 4
1532                  * octets, and ntohl(idx2[off * 2 + 1]) in low 4
1533                  * octets.  But idx2[off * 2] is Zero!!!
1534                  */
1535                 ALLOC_GROW(opts->anomaly, opts->anomaly_nr + 1, opts->anomaly_alloc);
1536                 opts->anomaly[opts->anomaly_nr++] = ntohl(idx2[off * 2 + 1]);
1537         }
1538
1539         QSORT(opts->anomaly, opts->anomaly_nr, cmp_uint32);
1540 }
1541
1542 static void read_idx_option(struct pack_idx_option *opts, const char *pack_name)
1543 {
1544         struct packed_git *p = add_packed_git(pack_name, strlen(pack_name), 1);
1545
1546         if (!p)
1547                 die(_("Cannot open existing pack file '%s'"), pack_name);
1548         if (open_pack_index(p))
1549                 die(_("Cannot open existing pack idx file for '%s'"), pack_name);
1550
1551         /* Read the attributes from the existing idx file */
1552         opts->version = p->index_version;
1553
1554         if (opts->version == 2)
1555                 read_v2_anomalous_offsets(p, opts);
1556
1557         /*
1558          * Get rid of the idx file as we do not need it anymore.
1559          * NEEDSWORK: extract this bit from free_pack_by_name() in
1560          * sha1_file.c, perhaps?  It shouldn't matter very much as we
1561          * know we haven't installed this pack (hence we never have
1562          * read anything from it).
1563          */
1564         close_pack_index(p);
1565         free(p);
1566 }
1567
1568 static void show_pack_info(int stat_only)
1569 {
1570         int i, baseobjects = nr_objects - nr_ref_deltas - nr_ofs_deltas;
1571         unsigned long *chain_histogram = NULL;
1572
1573         if (deepest_delta)
1574                 chain_histogram = xcalloc(deepest_delta, sizeof(unsigned long));
1575
1576         for (i = 0; i < nr_objects; i++) {
1577                 struct object_entry *obj = &objects[i];
1578
1579                 if (is_delta_type(obj->type))
1580                         chain_histogram[obj_stat[i].delta_depth - 1]++;
1581                 if (stat_only)
1582                         continue;
1583                 printf("%s %-6s %lu %lu %"PRIuMAX,
1584                        sha1_to_hex(obj->idx.sha1),
1585                        typename(obj->real_type), obj->size,
1586                        (unsigned long)(obj[1].idx.offset - obj->idx.offset),
1587                        (uintmax_t)obj->idx.offset);
1588                 if (is_delta_type(obj->type)) {
1589                         struct object_entry *bobj = &objects[obj_stat[i].base_object_no];
1590                         printf(" %u %s", obj_stat[i].delta_depth, sha1_to_hex(bobj->idx.sha1));
1591                 }
1592                 putchar('\n');
1593         }
1594
1595         if (baseobjects)
1596                 printf_ln(Q_("non delta: %d object",
1597                              "non delta: %d objects",
1598                              baseobjects),
1599                           baseobjects);
1600         for (i = 0; i < deepest_delta; i++) {
1601                 if (!chain_histogram[i])
1602                         continue;
1603                 printf_ln(Q_("chain length = %d: %lu object",
1604                              "chain length = %d: %lu objects",
1605                              chain_histogram[i]),
1606                           i + 1,
1607                           chain_histogram[i]);
1608         }
1609 }
1610
1611 static const char *derive_filename(const char *pack_name, const char *suffix,
1612                                    struct strbuf *buf)
1613 {
1614         size_t len;
1615         if (!strip_suffix(pack_name, ".pack", &len))
1616                 die(_("packfile name '%s' does not end with '.pack'"),
1617                     pack_name);
1618         strbuf_add(buf, pack_name, len);
1619         strbuf_addstr(buf, suffix);
1620         return buf->buf;
1621 }
1622
1623 int cmd_index_pack(int argc, const char **argv, const char *prefix)
1624 {
1625         int i, fix_thin_pack = 0, verify = 0, stat_only = 0;
1626         const char *curr_index;
1627         const char *index_name = NULL, *pack_name = NULL;
1628         const char *keep_name = NULL, *keep_msg = NULL;
1629         struct strbuf index_name_buf = STRBUF_INIT,
1630                       keep_name_buf = STRBUF_INIT;
1631         struct pack_idx_entry **idx_objects;
1632         struct pack_idx_option opts;
1633         unsigned char pack_sha1[20];
1634         unsigned foreign_nr = 1;        /* zero is a "good" value, assume bad */
1635         int report_end_of_input = 0;
1636
1637         if (argc == 2 && !strcmp(argv[1], "-h"))
1638                 usage(index_pack_usage);
1639
1640         check_replace_refs = 0;
1641         fsck_options.walk = mark_link;
1642
1643         reset_pack_idx_option(&opts);
1644         git_config(git_index_pack_config, &opts);
1645         if (prefix && chdir(prefix))
1646                 die(_("Cannot come back to cwd"));
1647
1648         for (i = 1; i < argc; i++) {
1649                 const char *arg = argv[i];
1650
1651                 if (*arg == '-') {
1652                         if (!strcmp(arg, "--stdin")) {
1653                                 from_stdin = 1;
1654                         } else if (!strcmp(arg, "--fix-thin")) {
1655                                 fix_thin_pack = 1;
1656                         } else if (!strcmp(arg, "--strict")) {
1657                                 strict = 1;
1658                                 do_fsck_object = 1;
1659                         } else if (skip_prefix(arg, "--strict=", &arg)) {
1660                                 strict = 1;
1661                                 do_fsck_object = 1;
1662                                 fsck_set_msg_types(&fsck_options, arg);
1663                         } else if (!strcmp(arg, "--check-self-contained-and-connected")) {
1664                                 strict = 1;
1665                                 check_self_contained_and_connected = 1;
1666                         } else if (!strcmp(arg, "--verify")) {
1667                                 verify = 1;
1668                         } else if (!strcmp(arg, "--verify-stat")) {
1669                                 verify = 1;
1670                                 show_stat = 1;
1671                         } else if (!strcmp(arg, "--verify-stat-only")) {
1672                                 verify = 1;
1673                                 show_stat = 1;
1674                                 stat_only = 1;
1675                         } else if (!strcmp(arg, "--keep")) {
1676                                 keep_msg = "";
1677                         } else if (starts_with(arg, "--keep=")) {
1678                                 keep_msg = arg + 7;
1679                         } else if (starts_with(arg, "--threads=")) {
1680                                 char *end;
1681                                 nr_threads = strtoul(arg+10, &end, 0);
1682                                 if (!arg[10] || *end || nr_threads < 0)
1683                                         usage(index_pack_usage);
1684 #ifdef NO_PTHREADS
1685                                 if (nr_threads != 1)
1686                                         warning(_("no threads support, "
1687                                                   "ignoring %s"), arg);
1688                                 nr_threads = 1;
1689 #endif
1690                         } else if (starts_with(arg, "--pack_header=")) {
1691                                 struct pack_header *hdr;
1692                                 char *c;
1693
1694                                 hdr = (struct pack_header *)input_buffer;
1695                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
1696                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
1697                                 if (*c != ',')
1698                                         die(_("bad %s"), arg);
1699                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
1700                                 if (*c)
1701                                         die(_("bad %s"), arg);
1702                                 input_len = sizeof(*hdr);
1703                         } else if (!strcmp(arg, "-v")) {
1704                                 verbose = 1;
1705                         } else if (!strcmp(arg, "--show-resolving-progress")) {
1706                                 show_resolving_progress = 1;
1707                         } else if (!strcmp(arg, "--report-end-of-input")) {
1708                                 report_end_of_input = 1;
1709                         } else if (!strcmp(arg, "-o")) {
1710                                 if (index_name || (i+1) >= argc)
1711                                         usage(index_pack_usage);
1712                                 index_name = argv[++i];
1713                         } else if (starts_with(arg, "--index-version=")) {
1714                                 char *c;
1715                                 opts.version = strtoul(arg + 16, &c, 10);
1716                                 if (opts.version > 2)
1717                                         die(_("bad %s"), arg);
1718                                 if (*c == ',')
1719                                         opts.off32_limit = strtoul(c+1, &c, 0);
1720                                 if (*c || opts.off32_limit & 0x80000000)
1721                                         die(_("bad %s"), arg);
1722                         } else if (skip_prefix(arg, "--max-input-size=", &arg)) {
1723                                 max_input_size = strtoumax(arg, NULL, 10);
1724                         } else
1725                                 usage(index_pack_usage);
1726                         continue;
1727                 }
1728
1729                 if (pack_name)
1730                         usage(index_pack_usage);
1731                 pack_name = arg;
1732         }
1733
1734         if (!pack_name && !from_stdin)
1735                 usage(index_pack_usage);
1736         if (fix_thin_pack && !from_stdin)
1737                 die(_("--fix-thin cannot be used without --stdin"));
1738         if (from_stdin && !startup_info->have_repository)
1739                 die(_("--stdin requires a git repository"));
1740         if (!index_name && pack_name)
1741                 index_name = derive_filename(pack_name, ".idx", &index_name_buf);
1742         if (keep_msg && !keep_name && pack_name)
1743                 keep_name = derive_filename(pack_name, ".keep", &keep_name_buf);
1744
1745         if (verify) {
1746                 if (!index_name)
1747                         die(_("--verify with no packfile name given"));
1748                 read_idx_option(&opts, index_name);
1749                 opts.flags |= WRITE_IDX_VERIFY | WRITE_IDX_STRICT;
1750         }
1751         if (strict)
1752                 opts.flags |= WRITE_IDX_STRICT;
1753
1754 #ifndef NO_PTHREADS
1755         if (!nr_threads) {
1756                 nr_threads = online_cpus();
1757                 /* An experiment showed that more threads does not mean faster */
1758                 if (nr_threads > 3)
1759                         nr_threads = 3;
1760         }
1761 #endif
1762
1763         curr_pack = open_pack_file(pack_name);
1764         parse_pack_header();
1765         objects = xcalloc(st_add(nr_objects, 1), sizeof(struct object_entry));
1766         if (show_stat)
1767                 obj_stat = xcalloc(st_add(nr_objects, 1), sizeof(struct object_stat));
1768         ofs_deltas = xcalloc(nr_objects, sizeof(struct ofs_delta_entry));
1769         parse_pack_objects(pack_sha1);
1770         if (report_end_of_input)
1771                 write_in_full(2, "\0", 1);
1772         resolve_deltas();
1773         conclude_pack(fix_thin_pack, curr_pack, pack_sha1);
1774         free(ofs_deltas);
1775         free(ref_deltas);
1776         if (strict)
1777                 foreign_nr = check_objects();
1778
1779         if (show_stat)
1780                 show_pack_info(stat_only);
1781
1782         ALLOC_ARRAY(idx_objects, nr_objects);
1783         for (i = 0; i < nr_objects; i++)
1784                 idx_objects[i] = &objects[i].idx;
1785         curr_index = write_idx_file(index_name, idx_objects, nr_objects, &opts, pack_sha1);
1786         free(idx_objects);
1787
1788         if (!verify)
1789                 final(pack_name, curr_pack,
1790                       index_name, curr_index,
1791                       keep_name, keep_msg,
1792                       pack_sha1);
1793         else
1794                 close(input_fd);
1795         free(objects);
1796         strbuf_release(&index_name_buf);
1797         strbuf_release(&keep_name_buf);
1798         if (pack_name == NULL)
1799                 free((void *) curr_pack);
1800         if (index_name == NULL)
1801                 free((void *) curr_index);
1802
1803         /*
1804          * Let the caller know this pack is not self contained
1805          */
1806         if (check_self_contained_and_connected && foreign_nr)
1807                 return 1;
1808
1809         return 0;
1810 }