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
  16 static const char index_pack_usage[] =
  17 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
  18
  19 struct object_entry {
  20         struct pack_idx_entry idx;
  21         unsigned long size;
  22         unsigned char hdr_size;
  23         signed char type;
  24         signed char real_type;
  25 };
  26
  27 struct object_stat {
  28         unsigned delta_depth;
  29         int base_object_no;
  30 };
  31
  32 struct base_data {
  33         struct base_data *base;
  34         struct base_data *child;
  35         struct object_entry *obj;
  36         void *data;
  37         unsigned long size;
  38         int ref_first, ref_last;
  39         int ofs_first, ofs_last;
  40 };
  41
  42 struct thread_local {
  43 #ifndef NO_PTHREADS
  44         pthread_t thread;
  45 #endif
  46         struct base_data *base_cache;
  47         size_t base_cache_used;
  48         int pack_fd;
  49 };
  50
  51 #define FLAG_LINK (1u<<20)
  52 #define FLAG_CHECKED (1u<<21)
  53
  54 struct ofs_delta_entry {
  55         off_t offset;
  56         int obj_no;
  57 };
  58
  59 struct ref_delta_entry {
  60         unsigned char sha1[20];
  61         int obj_no;
  62 };
  63
  64 static struct object_entry *objects;
  65 static struct object_stat *obj_stat;
  66 static struct ofs_delta_entry *ofs_deltas;
  67 static struct ref_delta_entry *ref_deltas;
  68 static struct thread_local nothread_data;
  69 static int nr_objects;
  70 static int nr_ofs_deltas;
  71 static int nr_ref_deltas;
  72 static int ref_deltas_alloc;
  73 static int nr_resolved_deltas;
  74 static int nr_threads;
  75
  76 static int from_stdin;
  77 static int strict;
  78 static int do_fsck_object;
  79 static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
  80 static int verbose;
  81 static int show_resolving_progress;
  82 static int show_stat;
  83 static int check_self_contained_and_connected;
  84
  85 static struct progress *progress;
  86
  87 /* We always read in 4kB chunks. */
  88 static unsigned char input_buffer[4096];
  89 static unsigned int input_offset, input_len;
  90 static off_t consumed_bytes;
  91 static off_t max_input_size;
  92 static unsigned deepest_delta;
  93 static git_SHA_CTX input_ctx;
  94 static uint32_t input_crc32;
  95 static int input_fd, output_fd;
  96 static const char *curr_pack;
  97
  98 #ifndef NO_PTHREADS
  99
 100 static struct thread_local *thread_data;
 101 static int nr_dispatched;
 102 static int threads_active;
 103
 104 static pthread_mutex_t read_mutex;
 105 #define read_lock()             lock_mutex(&read_mutex)
 106 #define read_unlock()           unlock_mutex(&read_mutex)
 107
 108 static pthread_mutex_t counter_mutex;
 109 #define counter_lock()          lock_mutex(&counter_mutex)
 110 #define counter_unlock()        unlock_mutex(&counter_mutex)
 111
 112 static pthread_mutex_t work_mutex;
 113 #define work_lock()             lock_mutex(&work_mutex)
 114 #define work_unlock()           unlock_mutex(&work_mutex)
 115
 116 static pthread_mutex_t deepest_delta_mutex;
 117 #define deepest_delta_lock()    lock_mutex(&deepest_delta_mutex)
 118 #define deepest_delta_unlock()  unlock_mutex(&deepest_delta_mutex)
 119
 120 static pthread_mutex_t type_cas_mutex;
 121 #define type_cas_lock()         lock_mutex(&type_cas_mutex)
 122 #define type_cas_unlock()       unlock_mutex(&type_cas_mutex)
 123
 124 static pthread_key_t key;
 125
 126 static inline void lock_mutex(pthread_mutex_t *mutex)
 127 {
 128         if (threads_active)
 129                 pthread_mutex_lock(mutex);
 130 }
 131
 132 static inline void unlock_mutex(pthread_mutex_t *mutex)
 133 {
 134         if (threads_active)
 135                 pthread_mutex_unlock(mutex);
 136 }
 137
 138 /*
 139  * Mutex and conditional variable can't be statically-initialized on Windows.
 140  */
 141 static void init_thread(void)
 142 {
 143         int i;
 144         init_recursive_mutex(&read_mutex);
 145         pthread_mutex_init(&counter_mutex, NULL);
 146         pthread_mutex_init(&work_mutex, NULL);
 147         pthread_mutex_init(&type_cas_mutex, NULL);
 148         if (show_stat)
 149                 pthread_mutex_init(&deepest_delta_mutex, NULL);
 150         pthread_key_create(&key, NULL);
 151         thread_data = xcalloc(nr_threads, sizeof(*thread_data));
 152         for (i = 0; i < nr_threads; i++) {
 153                 thread_data[i].pack_fd = open(curr_pack, O_RDONLY);
 154                 if (thread_data[i].pack_fd == -1)
 155                         die_errno(_("unable to open %s"), curr_pack);
 156         }
 157
 158         threads_active = 1;
 159 }
 160
 161 static void cleanup_thread(void)
 162 {
 163         int i;
 164         if (!threads_active)
 165                 return;
 166         threads_active = 0;
 167         pthread_mutex_destroy(&read_mutex);
 168         pthread_mutex_destroy(&counter_mutex);
 169         pthread_mutex_destroy(&work_mutex);
 170         pthread_mutex_destroy(&type_cas_mutex);
 171         if (show_stat)
 172                 pthread_mutex_destroy(&deepest_delta_mutex);
 173         for (i = 0; i < nr_threads; i++)
 174                 close(thread_data[i].pack_fd);
 175         pthread_key_delete(key);
 176         free(thread_data);
 177 }
 178
 179 #else
 180
 181 #define read_lock()
 182 #define read_unlock()
 183
 184 #define counter_lock()
 185 #define counter_unlock()
 186
 187 #define work_lock()
 188 #define work_unlock()
 189
 190 #define deepest_delta_lock()
 191 #define deepest_delta_unlock()
 192
 193 #define type_cas_lock()
 194 #define type_cas_unlock()
 195
 196 #endif
 197
 198
 199 static int mark_link(struct object *obj, int type, void *data, struct fsck_options *options)
 200 {
 201         if (!obj)
 202                 return -1;
 203
 204         if (type != OBJ_ANY && obj->type != type)
 205                 die(_("object type mismatch at %s"), oid_to_hex(&obj->oid));
 206
 207         obj->flags |= FLAG_LINK;
 208         return 0;
 209 }
 210
 211 /* The content of each linked object must have been checked
 212    or it must be already present in the object database */
 213 static unsigned check_object(struct object *obj)
 214 {
 215         if (!obj)
 216                 return 0;
 217
 218         if (!(obj->flags & FLAG_LINK))
 219                 return 0;
 220
 221         if (!(obj->flags & FLAG_CHECKED)) {
 222                 unsigned long size;
 223                 int type = sha1_object_info(obj->oid.hash, &size);
 224                 if (type <= 0)
 225                         die(_("did not receive expected object %s"),
 226                               oid_to_hex(&obj->oid));
 227                 if (type != obj->type)
 228                         die(_("object %s: expected type %s, found %s"),
 229                             oid_to_hex(&obj->oid),
 230                             typename(obj->type), typename(type));
 231                 obj->flags |= FLAG_CHECKED;
 232                 return 1;
 233         }
 234
 235         return 0;
 236 }
 237
 238 static unsigned check_objects(void)
 239 {
 240         unsigned i, max, foreign_nr = 0;
 241
 242         max = get_max_object_index();
 243         for (i = 0; i < max; i++)
 244                 foreign_nr += check_object(get_indexed_object(i));
 245         return foreign_nr;
 246 }
 247
 248
 249 /* Discard current buffer used content. */
 250 static void flush(void)
 251 {
 252         if (input_offset) {
 253                 if (output_fd >= 0)
 254                         write_or_die(output_fd, input_buffer, input_offset);
 255                 git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 256                 memmove(input_buffer, input_buffer + input_offset, input_len);
 257                 input_offset = 0;
 258         }
 259 }
 260
 261 /*
 262  * Make sure at least "min" bytes are available in the buffer, and
 263  * return the pointer to the buffer.
 264  */
 265 static void *fill(int min)
 266 {
 267         if (min <= input_len)
 268                 return input_buffer + input_offset;
 269         if (min > sizeof(input_buffer))
 270                 die(Q_("cannot fill %d byte",
 271                        "cannot fill %d bytes",
 272                        min),
 273                     min);
 274         flush();
 275         do {
 276                 ssize_t ret = xread(input_fd, input_buffer + input_len,
 277                                 sizeof(input_buffer) - input_len);
 278                 if (ret <= 0) {
 279                         if (!ret)
 280                                 die(_("early EOF"));
 281                         die_errno(_("read error on input"));
 282                 }
 283                 input_len += ret;
 284                 if (from_stdin)
 285                         display_throughput(progress, consumed_bytes + input_len);
 286         } while (input_len < min);
 287         return input_buffer;
 288 }
 289
 290 static void use(int bytes)
 291 {
 292         if (bytes > input_len)
 293                 die(_("used more bytes than were available"));
 294         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 295         input_len -= bytes;
 296         input_offset += bytes;
 297
 298         /* make sure off_t is sufficiently large not to wrap */
 299         if (signed_add_overflows(consumed_bytes, bytes))
 300                 die(_("pack too large for current definition of off_t"));
 301         consumed_bytes += bytes;
 302         if (max_input_size && consumed_bytes > max_input_size)
 303                 die(_("pack exceeds maximum allowed size"));
 304 }
 305
 306 static const char *open_pack_file(const char *pack_name)
 307 {
 308         if (from_stdin) {
 309                 input_fd = 0;
 310                 if (!pack_name) {
 311                         struct strbuf tmp_file = STRBUF_INIT;
 312                         output_fd = odb_mkstemp(&tmp_file,
 313                                                 "pack/tmp_pack_XXXXXX");
 314                         pack_name = strbuf_detach(&tmp_file, NULL);
 315                 } else {
 316                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 317                         if (output_fd < 0)
 318                                 die_errno(_("unable to create '%s'"), pack_name);
 319                 }
 320                 nothread_data.pack_fd = output_fd;
 321         } else {
 322                 input_fd = open(pack_name, O_RDONLY);
 323                 if (input_fd < 0)
 324                         die_errno(_("cannot open packfile '%s'"), pack_name);
 325                 output_fd = -1;
 326                 nothread_data.pack_fd = input_fd;
 327         }
 328         git_SHA1_Init(&input_ctx);
 329         return pack_name;
 330 }
 331
 332 static void parse_pack_header(void)
 333 {
 334         struct pack_header *hdr = fill(sizeof(struct pack_header));
 335
 336         /* Header consistency check */
 337         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 338                 die(_("pack signature mismatch"));
 339         if (!pack_version_ok(hdr->hdr_version))
 340                 die(_("pack version %"PRIu32" unsupported"),
 341                         ntohl(hdr->hdr_version));
 342
 343         nr_objects = ntohl(hdr->hdr_entries);
 344         use(sizeof(struct pack_header));
 345 }
 346
 347 static NORETURN void bad_object(off_t offset, const char *format,
 348                        ...) __attribute__((format (printf, 2, 3)));
 349
 350 static NORETURN void bad_object(off_t offset, const char *format, ...)
 351 {
 352         va_list params;
 353         char buf[1024];
 354
 355         va_start(params, format);
 356         vsnprintf(buf, sizeof(buf), format, params);
 357         va_end(params);
 358         die(_("pack has bad object at offset %"PRIuMAX": %s"),
 359             (uintmax_t)offset, buf);
 360 }
 361
 362 static inline struct thread_local *get_thread_data(void)
 363 {
 364 #ifndef NO_PTHREADS
 365         if (threads_active)
 366                 return pthread_getspecific(key);
 367         assert(!threads_active &&
 368                "This should only be reached when all threads are gone");
 369 #endif
 370         return &nothread_data;
 371 }
 372
 373 #ifndef NO_PTHREADS
 374 static void set_thread_data(struct thread_local *data)
 375 {
 376         if (threads_active)
 377                 pthread_setspecific(key, data);
 378 }
 379 #endif
 380
 381 static struct base_data *alloc_base_data(void)
 382 {
 383         struct base_data *base = xcalloc(1, sizeof(struct base_data));
 384         base->ref_last = -1;
 385         base->ofs_last = -1;
 386         return base;
 387 }
 388
 389 static void free_base_data(struct base_data *c)
 390 {
 391         if (c->data) {
 392                 FREE_AND_NULL(c->data);
 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_AND_NULL(data);
 609         }
 610         return data;
 611 }
 612
 613 static void *get_data_from_pack(struct object_entry *obj)
 614 {
 615         return unpack_data(obj, NULL, NULL);
 616 }
 617
 618 static int compare_ofs_delta_bases(off_t offset1, off_t offset2,
 619                                    enum object_type type1,
 620                                    enum object_type type2)
 621 {
 622         int cmp = type1 - type2;
 623         if (cmp)
 624                 return cmp;
 625         return offset1 < offset2 ? -1 :
 626                offset1 > offset2 ?  1 :
 627                0;
 628 }
 629
 630 static int find_ofs_delta(const off_t offset, enum object_type type)
 631 {
 632         int first = 0, last = nr_ofs_deltas;
 633
 634         while (first < last) {
 635                 int next = (first + last) / 2;
 636                 struct ofs_delta_entry *delta = &ofs_deltas[next];
 637                 int cmp;
 638
 639                 cmp = compare_ofs_delta_bases(offset, delta->offset,
 640                                               type, objects[delta->obj_no].type);
 641                 if (!cmp)
 642                         return next;
 643                 if (cmp < 0) {
 644                         last = next;
 645                         continue;
 646                 }
 647                 first = next+1;
 648         }
 649         return -first-1;
 650 }
 651
 652 static void find_ofs_delta_children(off_t offset,
 653                                     int *first_index, int *last_index,
 654                                     enum object_type type)
 655 {
 656         int first = find_ofs_delta(offset, type);
 657         int last = first;
 658         int end = nr_ofs_deltas - 1;
 659
 660         if (first < 0) {
 661                 *first_index = 0;
 662                 *last_index = -1;
 663                 return;
 664         }
 665         while (first > 0 && ofs_deltas[first - 1].offset == offset)
 666                 --first;
 667         while (last < end && ofs_deltas[last + 1].offset == offset)
 668                 ++last;
 669         *first_index = first;
 670         *last_index = last;
 671 }
 672
 673 static int compare_ref_delta_bases(const unsigned char *sha1,
 674                                    const unsigned char *sha2,
 675                                    enum object_type type1,
 676                                    enum object_type type2)
 677 {
 678         int cmp = type1 - type2;
 679         if (cmp)
 680                 return cmp;
 681         return hashcmp(sha1, sha2);
 682 }
 683
 684 static int find_ref_delta(const unsigned char *sha1, enum object_type type)
 685 {
 686         int first = 0, last = nr_ref_deltas;
 687
 688         while (first < last) {
 689                 int next = (first + last) / 2;
 690                 struct ref_delta_entry *delta = &ref_deltas[next];
 691                 int cmp;
 692
 693                 cmp = compare_ref_delta_bases(sha1, delta->sha1,
 694                                               type, objects[delta->obj_no].type);
 695                 if (!cmp)
 696                         return next;
 697                 if (cmp < 0) {
 698                         last = next;
 699                         continue;
 700                 }
 701                 first = next+1;
 702         }
 703         return -first-1;
 704 }
 705
 706 static void find_ref_delta_children(const unsigned char *sha1,
 707                                     int *first_index, int *last_index,
 708                                     enum object_type type)
 709 {
 710         int first = find_ref_delta(sha1, type);
 711         int last = first;
 712         int end = nr_ref_deltas - 1;
 713
 714         if (first < 0) {
 715                 *first_index = 0;
 716                 *last_index = -1;
 717                 return;
 718         }
 719         while (first > 0 && !hashcmp(ref_deltas[first - 1].sha1, sha1))
 720                 --first;
 721         while (last < end && !hashcmp(ref_deltas[last + 1].sha1, sha1))
 722                 ++last;
 723         *first_index = first;
 724         *last_index = last;
 725 }
 726
 727 struct compare_data {
 728         struct object_entry *entry;
 729         struct git_istream *st;
 730         unsigned char *buf;
 731         unsigned long buf_size;
 732 };
 733
 734 static int compare_objects(const unsigned char *buf, unsigned long size,
 735                            void *cb_data)
 736 {
 737         struct compare_data *data = cb_data;
 738
 739         if (data->buf_size < size) {
 740                 free(data->buf);
 741                 data->buf = xmalloc(size);
 742                 data->buf_size = size;
 743         }
 744
 745         while (size) {
 746                 ssize_t len = read_istream(data->st, data->buf, size);
 747                 if (len == 0)
 748                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 749                             oid_to_hex(&data->entry->idx.oid));
 750                 if (len < 0)
 751                         die(_("unable to read %s"),
 752                             oid_to_hex(&data->entry->idx.oid));
 753                 if (memcmp(buf, data->buf, len))
 754                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 755                             oid_to_hex(&data->entry->idx.oid));
 756                 size -= len;
 757                 buf += len;
 758         }
 759         return 0;
 760 }
 761
 762 static int check_collison(struct object_entry *entry)
 763 {
 764         struct compare_data data;
 765         enum object_type type;
 766         unsigned long size;
 767
 768         if (entry->size <= big_file_threshold || entry->type != OBJ_BLOB)
 769                 return -1;
 770
 771         memset(&data, 0, sizeof(data));
 772         data.entry = entry;
 773         data.st = open_istream(entry->idx.oid.hash, &type, &size, NULL);
 774         if (!data.st)
 775                 return -1;
 776         if (size != entry->size || type != entry->type)
 777                 die(_("SHA1 COLLISION FOUND WITH %s !"),
 778                     oid_to_hex(&entry->idx.oid));
 779         unpack_data(entry, compare_objects, &data);
 780         close_istream(data.st);
 781         free(data.buf);
 782         return 0;
 783 }
 784
 785 static void sha1_object(const void *data, struct object_entry *obj_entry,
 786                         unsigned long size, enum object_type type,
 787                         const struct object_id *oid)
 788 {
 789         void *new_data = NULL;
 790         int collision_test_needed = 0;
 791
 792         assert(data || obj_entry);
 793
 794         if (startup_info->have_repository) {
 795                 read_lock();
 796                 collision_test_needed =
 797                         has_sha1_file_with_flags(oid->hash, OBJECT_INFO_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(oid->hash, &has_size);
 813                 if (has_type < 0)
 814                         die(_("cannot read existing object info %s"), oid_to_hex(oid));
 815                 if (has_type != type || has_size != size)
 816                         die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
 817                 has_data = read_sha1_file(oid->hash, &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"), oid_to_hex(oid));
 823                 if (size != has_size || type != has_type ||
 824                     memcmp(data, has_data, size) != 0)
 825                         die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
 826                 free(has_data);
 827         }
 828
 829         if (strict) {
 830                 read_lock();
 831                 if (type == OBJ_BLOB) {
 832                         struct blob *blob = lookup_blob(oid);
 833                         if (blob)
 834                                 blob->object.flags |= FLAG_CHECKED;
 835                         else
 836                                 die(_("invalid blob object %s"), oid_to_hex(oid));
 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(oid, type, size, buf,
 849                                                   &eaten);
 850                         if (!obj)
 851                                 die(_("invalid %s"), typename(type));
 852                         if (do_fsck_object &&
 853                             fsck_object(obj, buf, size, &fsck_options))
 854                                 die(_("Error in object"));
 855                         if (fsck_walk(obj, NULL, &fsck_options))
 856                                 die(_("Not all child objects of %s are reachable"), oid_to_hex(&obj->oid));
 857
 858                         if (obj->type == OBJ_TREE) {
 859                                 struct tree *item = (struct tree *) obj;
 860                                 item->buffer = NULL;
 861                                 obj->parsed = 0;
 862                         }
 863                         if (obj->type == OBJ_COMMIT) {
 864                                 struct commit *commit = (struct commit *) obj;
 865                                 if (detach_commit_buffer(commit, NULL) != data)
 866                                         die("BUG: parse_object_buffer transmogrified our buffer");
 867                         }
 868                         obj->flags |= FLAG_CHECKED;
 869                 }
 870                 read_unlock();
 871         }
 872
 873         free(new_data);
 874 }
 875
 876 /*
 877  * This function is part of find_unresolved_deltas(). There are two
 878  * walkers going in the opposite ways.
 879  *
 880  * The first one in find_unresolved_deltas() traverses down from
 881  * parent node to children, deflating nodes along the way. However,
 882  * memory for deflated nodes is limited by delta_base_cache_limit, so
 883  * at some point parent node's deflated content may be freed.
 884  *
 885  * The second walker is this function, which goes from current node up
 886  * to top parent if necessary to deflate the node. In normal
 887  * situation, its parent node would be already deflated, so it just
 888  * needs to apply delta.
 889  *
 890  * In the worst case scenario, parent node is no longer deflated because
 891  * we're running out of delta_base_cache_limit; we need to re-deflate
 892  * parents, possibly up to the top base.
 893  *
 894  * All deflated objects here are subject to be freed if we exceed
 895  * delta_base_cache_limit, just like in find_unresolved_deltas(), we
 896  * just need to make sure the last node is not freed.
 897  */
 898 static void *get_base_data(struct base_data *c)
 899 {
 900         if (!c->data) {
 901                 struct object_entry *obj = c->obj;
 902                 struct base_data **delta = NULL;
 903                 int delta_nr = 0, delta_alloc = 0;
 904
 905                 while (is_delta_type(c->obj->type) && !c->data) {
 906                         ALLOC_GROW(delta, delta_nr + 1, delta_alloc);
 907                         delta[delta_nr++] = c;
 908                         c = c->base;
 909                 }
 910                 if (!delta_nr) {
 911                         c->data = get_data_from_pack(obj);
 912                         c->size = obj->size;
 913                         get_thread_data()->base_cache_used += c->size;
 914                         prune_base_data(c);
 915                 }
 916                 for (; delta_nr > 0; delta_nr--) {
 917                         void *base, *raw;
 918                         c = delta[delta_nr - 1];
 919                         obj = c->obj;
 920                         base = get_base_data(c->base);
 921                         raw = get_data_from_pack(obj);
 922                         c->data = patch_delta(
 923                                 base, c->base->size,
 924                                 raw, obj->size,
 925                                 &c->size);
 926                         free(raw);
 927                         if (!c->data)
 928                                 bad_object(obj->idx.offset, _("failed to apply delta"));
 929                         get_thread_data()->base_cache_used += c->size;
 930                         prune_base_data(c);
 931                 }
 932                 free(delta);
 933         }
 934         return c->data;
 935 }
 936
 937 static void resolve_delta(struct object_entry *delta_obj,
 938                           struct base_data *base, struct base_data *result)
 939 {
 940         void *base_data, *delta_data;
 941
 942         if (show_stat) {
 943                 int i = delta_obj - objects;
 944                 int j = base->obj - objects;
 945                 obj_stat[i].delta_depth = obj_stat[j].delta_depth + 1;
 946                 deepest_delta_lock();
 947                 if (deepest_delta < obj_stat[i].delta_depth)
 948                         deepest_delta = obj_stat[i].delta_depth;
 949                 deepest_delta_unlock();
 950                 obj_stat[i].base_object_no = j;
 951         }
 952         delta_data = get_data_from_pack(delta_obj);
 953         base_data = get_base_data(base);
 954         result->obj = delta_obj;
 955         result->data = patch_delta(base_data, base->size,
 956                                    delta_data, delta_obj->size, &result->size);
 957         free(delta_data);
 958         if (!result->data)
 959                 bad_object(delta_obj->idx.offset, _("failed to apply delta"));
 960         hash_sha1_file(result->data, result->size,
 961                        typename(delta_obj->real_type),
 962                        delta_obj->idx.oid.hash);
 963         sha1_object(result->data, NULL, result->size, delta_obj->real_type,
 964                     &delta_obj->idx.oid);
 965         counter_lock();
 966         nr_resolved_deltas++;
 967         counter_unlock();
 968 }
 969
 970 /*
 971  * Standard boolean compare-and-swap: atomically check whether "*type" is
 972  * "want"; if so, swap in "set" and return true. Otherwise, leave it untouched
 973  * and return false.
 974  */
 975 static int compare_and_swap_type(signed char *type,
 976                                  enum object_type want,
 977                                  enum object_type set)
 978 {
 979         enum object_type old;
 980
 981         type_cas_lock();
 982         old = *type;
 983         if (old == want)
 984                 *type = set;
 985         type_cas_unlock();
 986
 987         return old == want;
 988 }
 989
 990 static struct base_data *find_unresolved_deltas_1(struct base_data *base,
 991                                                   struct base_data *prev_base)
 992 {
 993         if (base->ref_last == -1 && base->ofs_last == -1) {
 994                 find_ref_delta_children(base->obj->idx.oid.hash,
 995                                         &base->ref_first, &base->ref_last,
 996                                         OBJ_REF_DELTA);
 997
 998                 find_ofs_delta_children(base->obj->idx.offset,
 999                                         &base->ofs_first, &base->ofs_last,
1000                                         OBJ_OFS_DELTA);
1001
1002                 if (base->ref_last == -1 && base->ofs_last == -1) {
1003                         free(base->data);
1004                         return NULL;
1005                 }
1006
1007                 link_base_data(prev_base, base);
1008         }
1009
1010         if (base->ref_first <= base->ref_last) {
1011                 struct object_entry *child = objects + ref_deltas[base->ref_first].obj_no;
1012                 struct base_data *result = alloc_base_data();
1013
1014                 if (!compare_and_swap_type(&child->real_type, OBJ_REF_DELTA,
1015                                            base->obj->real_type))
1016                         die("BUG: child->real_type != OBJ_REF_DELTA");
1017
1018                 resolve_delta(child, base, result);
1019                 if (base->ref_first == base->ref_last && base->ofs_last == -1)
1020                         free_base_data(base);
1021
1022                 base->ref_first++;
1023                 return result;
1024         }
1025
1026         if (base->ofs_first <= base->ofs_last) {
1027                 struct object_entry *child = objects + ofs_deltas[base->ofs_first].obj_no;
1028                 struct base_data *result = alloc_base_data();
1029
1030                 assert(child->real_type == OBJ_OFS_DELTA);
1031                 child->real_type = base->obj->real_type;
1032                 resolve_delta(child, base, result);
1033                 if (base->ofs_first == base->ofs_last)
1034                         free_base_data(base);
1035
1036                 base->ofs_first++;
1037                 return result;
1038         }
1039
1040         unlink_base_data(base);
1041         return NULL;
1042 }
1043
1044 static void find_unresolved_deltas(struct base_data *base)
1045 {
1046         struct base_data *new_base, *prev_base = NULL;
1047         for (;;) {
1048                 new_base = find_unresolved_deltas_1(base, prev_base);
1049
1050                 if (new_base) {
1051                         prev_base = base;
1052                         base = new_base;
1053                 } else {
1054                         free(base);
1055                         base = prev_base;
1056                         if (!base)
1057                                 return;
1058                         prev_base = base->base;
1059                 }
1060         }
1061 }
1062
1063 static int compare_ofs_delta_entry(const void *a, const void *b)
1064 {
1065         const struct ofs_delta_entry *delta_a = a;
1066         const struct ofs_delta_entry *delta_b = b;
1067
1068         return delta_a->offset < delta_b->offset ? -1 :
1069                delta_a->offset > delta_b->offset ?  1 :
1070                0;
1071 }
1072
1073 static int compare_ref_delta_entry(const void *a, const void *b)
1074 {
1075         const struct ref_delta_entry *delta_a = a;
1076         const struct ref_delta_entry *delta_b = b;
1077
1078         return hashcmp(delta_a->sha1, delta_b->sha1);
1079 }
1080
1081 static void resolve_base(struct object_entry *obj)
1082 {
1083         struct base_data *base_obj = alloc_base_data();
1084         base_obj->obj = obj;
1085         base_obj->data = NULL;
1086         find_unresolved_deltas(base_obj);
1087 }
1088
1089 #ifndef NO_PTHREADS
1090 static void *threaded_second_pass(void *data)
1091 {
1092         set_thread_data(data);
1093         for (;;) {
1094                 int i;
1095                 counter_lock();
1096                 display_progress(progress, nr_resolved_deltas);
1097                 counter_unlock();
1098                 work_lock();
1099                 while (nr_dispatched < nr_objects &&
1100                        is_delta_type(objects[nr_dispatched].type))
1101                         nr_dispatched++;
1102                 if (nr_dispatched >= nr_objects) {
1103                         work_unlock();
1104                         break;
1105                 }
1106                 i = nr_dispatched++;
1107                 work_unlock();
1108
1109                 resolve_base(&objects[i]);
1110         }
1111         return NULL;
1112 }
1113 #endif
1114
1115 /*
1116  * First pass:
1117  * - find locations of all objects;
1118  * - calculate SHA1 of all non-delta objects;
1119  * - remember base (SHA1 or offset) for all deltas.
1120  */
1121 static void parse_pack_objects(unsigned char *sha1)
1122 {
1123         int i, nr_delays = 0;
1124         struct ofs_delta_entry *ofs_delta = ofs_deltas;
1125         unsigned char ref_delta_sha1[20];
1126         struct stat st;
1127
1128         if (verbose)
1129                 progress = start_progress(
1130                                 from_stdin ? _("Receiving objects") : _("Indexing objects"),
1131                                 nr_objects);
1132         for (i = 0; i < nr_objects; i++) {
1133                 struct object_entry *obj = &objects[i];
1134                 void *data = unpack_raw_entry(obj, &ofs_delta->offset,
1135                                               ref_delta_sha1,
1136                                               obj->idx.oid.hash);
1137                 obj->real_type = obj->type;
1138                 if (obj->type == OBJ_OFS_DELTA) {
1139                         nr_ofs_deltas++;
1140                         ofs_delta->obj_no = i;
1141                         ofs_delta++;
1142                 } else if (obj->type == OBJ_REF_DELTA) {
1143                         ALLOC_GROW(ref_deltas, nr_ref_deltas + 1, ref_deltas_alloc);
1144                         hashcpy(ref_deltas[nr_ref_deltas].sha1, ref_delta_sha1);
1145                         ref_deltas[nr_ref_deltas].obj_no = i;
1146                         nr_ref_deltas++;
1147                 } else if (!data) {
1148                         /* large blobs, check later */
1149                         obj->real_type = OBJ_BAD;
1150                         nr_delays++;
1151                 } else
1152                         sha1_object(data, NULL, obj->size, obj->type,
1153                                     &obj->idx.oid);
1154                 free(data);
1155                 display_progress(progress, i+1);
1156         }
1157         objects[i].idx.offset = consumed_bytes;
1158         stop_progress(&progress);
1159
1160         /* Check pack integrity */
1161         flush();
1162         git_SHA1_Final(sha1, &input_ctx);
1163         if (hashcmp(fill(20), sha1))
1164                 die(_("pack is corrupted (SHA1 mismatch)"));
1165         use(20);
1166
1167         /* If input_fd is a file, we should have reached its end now. */
1168         if (fstat(input_fd, &st))
1169                 die_errno(_("cannot fstat packfile"));
1170         if (S_ISREG(st.st_mode) &&
1171                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
1172                 die(_("pack has junk at the end"));
1173
1174         for (i = 0; i < nr_objects; i++) {
1175                 struct object_entry *obj = &objects[i];
1176                 if (obj->real_type != OBJ_BAD)
1177                         continue;
1178                 obj->real_type = obj->type;
1179                 sha1_object(NULL, obj, obj->size, obj->type,
1180                             &obj->idx.oid);
1181                 nr_delays--;
1182         }
1183         if (nr_delays)
1184                 die(_("confusion beyond insanity in parse_pack_objects()"));
1185 }
1186
1187 /*
1188  * Second pass:
1189  * - for all non-delta objects, look if it is used as a base for
1190  *   deltas;
1191  * - if used as a base, uncompress the object and apply all deltas,
1192  *   recursively checking if the resulting object is used as a base
1193  *   for some more deltas.
1194  */
1195 static void resolve_deltas(void)
1196 {
1197         int i;
1198
1199         if (!nr_ofs_deltas && !nr_ref_deltas)
1200                 return;
1201
1202         /* Sort deltas by base SHA1/offset for fast searching */
1203         QSORT(ofs_deltas, nr_ofs_deltas, compare_ofs_delta_entry);
1204         QSORT(ref_deltas, nr_ref_deltas, compare_ref_delta_entry);
1205
1206         if (verbose || show_resolving_progress)
1207                 progress = start_progress(_("Resolving deltas"),
1208                                           nr_ref_deltas + nr_ofs_deltas);
1209
1210 #ifndef NO_PTHREADS
1211         nr_dispatched = 0;
1212         if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) {
1213                 init_thread();
1214                 for (i = 0; i < nr_threads; i++) {
1215                         int ret = pthread_create(&thread_data[i].thread, NULL,
1216                                                  threaded_second_pass, thread_data + i);
1217                         if (ret)
1218                                 die(_("unable to create thread: %s"),
1219                                     strerror(ret));
1220                 }
1221                 for (i = 0; i < nr_threads; i++)
1222                         pthread_join(thread_data[i].thread, NULL);
1223                 cleanup_thread();
1224                 return;
1225         }
1226 #endif
1227
1228         for (i = 0; i < nr_objects; i++) {
1229                 struct object_entry *obj = &objects[i];
1230
1231                 if (is_delta_type(obj->type))
1232                         continue;
1233                 resolve_base(obj);
1234                 display_progress(progress, nr_resolved_deltas);
1235         }
1236 }
1237
1238 /*
1239  * Third pass:
1240  * - append objects to convert thin pack to full pack if required
1241  * - write the final 20-byte SHA-1
1242  */
1243 static void fix_unresolved_deltas(struct sha1file *f);
1244 static void conclude_pack(int fix_thin_pack, const char *curr_pack, unsigned char *pack_sha1)
1245 {
1246         if (nr_ref_deltas + nr_ofs_deltas == nr_resolved_deltas) {
1247                 stop_progress(&progress);
1248                 /* Flush remaining pack final 20-byte SHA1. */
1249                 flush();
1250                 return;
1251         }
1252
1253         if (fix_thin_pack) {
1254                 struct sha1file *f;
1255                 unsigned char read_sha1[20], tail_sha1[20];
1256                 struct strbuf msg = STRBUF_INIT;
1257                 int nr_unresolved = nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas;
1258                 int nr_objects_initial = nr_objects;
1259                 if (nr_unresolved <= 0)
1260                         die(_("confusion beyond insanity"));
1261                 REALLOC_ARRAY(objects, nr_objects + nr_unresolved + 1);
1262                 memset(objects + nr_objects + 1, 0,
1263                        nr_unresolved * sizeof(*objects));
1264                 f = sha1fd(output_fd, curr_pack);
1265                 fix_unresolved_deltas(f);
1266                 strbuf_addf(&msg, Q_("completed with %d local object",
1267                                      "completed with %d local objects",
1268                                      nr_objects - nr_objects_initial),
1269                             nr_objects - nr_objects_initial);
1270                 stop_progress_msg(&progress, msg.buf);
1271                 strbuf_release(&msg);
1272                 sha1close(f, tail_sha1, 0);
1273                 hashcpy(read_sha1, pack_sha1);
1274                 fixup_pack_header_footer(output_fd, pack_sha1,
1275                                          curr_pack, nr_objects,
1276                                          read_sha1, consumed_bytes-20);
1277                 if (hashcmp(read_sha1, tail_sha1) != 0)
1278                         die(_("Unexpected tail checksum for %s "
1279                               "(disk corruption?)"), curr_pack);
1280         }
1281         if (nr_ofs_deltas + nr_ref_deltas != nr_resolved_deltas)
1282                 die(Q_("pack has %d unresolved delta",
1283                        "pack has %d unresolved deltas",
1284                        nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas),
1285                     nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas);
1286 }
1287
1288 static int write_compressed(struct sha1file *f, void *in, unsigned int size)
1289 {
1290         git_zstream stream;
1291         int status;
1292         unsigned char outbuf[4096];
1293
1294         git_deflate_init(&stream, zlib_compression_level);
1295         stream.next_in = in;
1296         stream.avail_in = size;
1297
1298         do {
1299                 stream.next_out = outbuf;
1300                 stream.avail_out = sizeof(outbuf);
1301                 status = git_deflate(&stream, Z_FINISH);
1302                 sha1write(f, outbuf, sizeof(outbuf) - stream.avail_out);
1303         } while (status == Z_OK);
1304
1305         if (status != Z_STREAM_END)
1306                 die(_("unable to deflate appended object (%d)"), status);
1307         size = stream.total_out;
1308         git_deflate_end(&stream);
1309         return size;
1310 }
1311
1312 static struct object_entry *append_obj_to_pack(struct sha1file *f,
1313                                const unsigned char *sha1, void *buf,
1314                                unsigned long size, enum object_type type)
1315 {
1316         struct object_entry *obj = &objects[nr_objects++];
1317         unsigned char header[10];
1318         unsigned long s = size;
1319         int n = 0;
1320         unsigned char c = (type << 4) | (s & 15);
1321         s >>= 4;
1322         while (s) {
1323                 header[n++] = c | 0x80;
1324                 c = s & 0x7f;
1325                 s >>= 7;
1326         }
1327         header[n++] = c;
1328         crc32_begin(f);
1329         sha1write(f, header, n);
1330         obj[0].size = size;
1331         obj[0].hdr_size = n;
1332         obj[0].type = type;
1333         obj[0].real_type = type;
1334         obj[1].idx.offset = obj[0].idx.offset + n;
1335         obj[1].idx.offset += write_compressed(f, buf, size);
1336         obj[0].idx.crc32 = crc32_end(f);
1337         sha1flush(f);
1338         hashcpy(obj->idx.oid.hash, sha1);
1339         return obj;
1340 }
1341
1342 static int delta_pos_compare(const void *_a, const void *_b)
1343 {
1344         struct ref_delta_entry *a = *(struct ref_delta_entry **)_a;
1345         struct ref_delta_entry *b = *(struct ref_delta_entry **)_b;
1346         return a->obj_no - b->obj_no;
1347 }
1348
1349 static void fix_unresolved_deltas(struct sha1file *f)
1350 {
1351         struct ref_delta_entry **sorted_by_pos;
1352         int i;
1353
1354         /*
1355          * Since many unresolved deltas may well be themselves base objects
1356          * for more unresolved deltas, we really want to include the
1357          * smallest number of base objects that would cover as much delta
1358          * as possible by picking the
1359          * trunc deltas first, allowing for other deltas to resolve without
1360          * additional base objects.  Since most base objects are to be found
1361          * before deltas depending on them, a good heuristic is to start
1362          * resolving deltas in the same order as their position in the pack.
1363          */
1364         ALLOC_ARRAY(sorted_by_pos, nr_ref_deltas);
1365         for (i = 0; i < nr_ref_deltas; i++)
1366                 sorted_by_pos[i] = &ref_deltas[i];
1367         QSORT(sorted_by_pos, nr_ref_deltas, delta_pos_compare);
1368
1369         for (i = 0; i < nr_ref_deltas; i++) {
1370                 struct ref_delta_entry *d = sorted_by_pos[i];
1371                 enum object_type type;
1372                 struct base_data *base_obj = alloc_base_data();
1373
1374                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
1375                         continue;
1376                 base_obj->data = read_sha1_file(d->sha1, &type, &base_obj->size);
1377                 if (!base_obj->data)
1378                         continue;
1379
1380                 if (check_sha1_signature(d->sha1, base_obj->data,
1381                                 base_obj->size, typename(type)))
1382                         die(_("local object %s is corrupt"), sha1_to_hex(d->sha1));
1383                 base_obj->obj = append_obj_to_pack(f, d->sha1,
1384                                         base_obj->data, base_obj->size, type);
1385                 find_unresolved_deltas(base_obj);
1386                 display_progress(progress, nr_resolved_deltas);
1387         }
1388         free(sorted_by_pos);
1389 }
1390
1391 static void final(const char *final_pack_name, const char *curr_pack_name,
1392                   const char *final_index_name, const char *curr_index_name,
1393                   const char *keep_name, const char *keep_msg,
1394                   unsigned char *sha1)
1395 {
1396         const char *report = "pack";
1397         struct strbuf pack_name = STRBUF_INIT;
1398         struct strbuf index_name = STRBUF_INIT;
1399         struct strbuf keep_name_buf = STRBUF_INIT;
1400         int err;
1401
1402         if (!from_stdin) {
1403                 close(input_fd);
1404         } else {
1405                 fsync_or_die(output_fd, curr_pack_name);
1406                 err = close(output_fd);
1407                 if (err)
1408                         die_errno(_("error while closing pack file"));
1409         }
1410
1411         if (keep_msg) {
1412                 int keep_fd, keep_msg_len = strlen(keep_msg);
1413
1414                 if (!keep_name)
1415                         keep_name = odb_pack_name(&keep_name_buf, sha1, "keep");
1416
1417                 keep_fd = odb_pack_keep(keep_name);
1418                 if (keep_fd < 0) {
1419                         if (errno != EEXIST)
1420                                 die_errno(_("cannot write keep file '%s'"),
1421                                           keep_name);
1422                 } else {
1423                         if (keep_msg_len > 0) {
1424                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
1425                                 write_or_die(keep_fd, "\n", 1);
1426                         }
1427                         if (close(keep_fd) != 0)
1428                                 die_errno(_("cannot close written keep file '%s'"),
1429                                           keep_name);
1430                         report = "keep";
1431                 }
1432         }
1433
1434         if (final_pack_name != curr_pack_name) {
1435                 if (!final_pack_name)
1436                         final_pack_name = odb_pack_name(&pack_name, sha1, "pack");
1437                 if (finalize_object_file(curr_pack_name, final_pack_name))
1438                         die(_("cannot store pack file"));
1439         } else if (from_stdin)
1440                 chmod(final_pack_name, 0444);
1441
1442         if (final_index_name != curr_index_name) {
1443                 if (!final_index_name)
1444                         final_index_name = odb_pack_name(&index_name, sha1, "idx");
1445                 if (finalize_object_file(curr_index_name, final_index_name))
1446                         die(_("cannot store index file"));
1447         } else
1448                 chmod(final_index_name, 0444);
1449
1450         if (!from_stdin) {
1451                 printf("%s\n", sha1_to_hex(sha1));
1452         } else {
1453                 struct strbuf buf = STRBUF_INIT;
1454
1455                 strbuf_addf(&buf, "%s\t%s\n", report, sha1_to_hex(sha1));
1456                 write_or_die(1, buf.buf, buf.len);
1457                 strbuf_release(&buf);
1458
1459                 /*
1460                  * Let's just mimic git-unpack-objects here and write
1461                  * the last part of the input buffer to stdout.
1462                  */
1463                 while (input_len) {
1464                         err = xwrite(1, input_buffer + input_offset, input_len);
1465                         if (err <= 0)
1466                                 break;
1467                         input_len -= err;
1468                         input_offset += err;
1469                 }
1470         }
1471
1472         strbuf_release(&index_name);
1473         strbuf_release(&pack_name);
1474         strbuf_release(&keep_name_buf);
1475 }
1476
1477 static int git_index_pack_config(const char *k, const char *v, void *cb)
1478 {
1479         struct pack_idx_option *opts = cb;
1480
1481         if (!strcmp(k, "pack.indexversion")) {
1482                 opts->version = git_config_int(k, v);
1483                 if (opts->version > 2)
1484                         die(_("bad pack.indexversion=%"PRIu32), opts->version);
1485                 return 0;
1486         }
1487         if (!strcmp(k, "pack.threads")) {
1488                 nr_threads = git_config_int(k, v);
1489                 if (nr_threads < 0)
1490                         die(_("invalid number of threads specified (%d)"),
1491                             nr_threads);
1492 #ifdef NO_PTHREADS
1493                 if (nr_threads != 1)
1494                         warning(_("no threads support, ignoring %s"), k);
1495                 nr_threads = 1;
1496 #endif
1497                 return 0;
1498         }
1499         return git_default_config(k, v, cb);
1500 }
1501
1502 static int cmp_uint32(const void *a_, const void *b_)
1503 {
1504         uint32_t a = *((uint32_t *)a_);
1505         uint32_t b = *((uint32_t *)b_);
1506
1507         return (a < b) ? -1 : (a != b);
1508 }
1509
1510 static void read_v2_anomalous_offsets(struct packed_git *p,
1511                                       struct pack_idx_option *opts)
1512 {
1513         const uint32_t *idx1, *idx2;
1514         uint32_t i;
1515
1516         /* The address of the 4-byte offset table */
1517         idx1 = (((const uint32_t *)p->index_data)
1518                 + 2 /* 8-byte header */
1519                 + 256 /* fan out */
1520                 + 5 * p->num_objects /* 20-byte SHA-1 table */
1521                 + p->num_objects /* CRC32 table */
1522                 );
1523
1524         /* The address of the 8-byte offset table */
1525         idx2 = idx1 + p->num_objects;
1526
1527         for (i = 0; i < p->num_objects; i++) {
1528                 uint32_t off = ntohl(idx1[i]);
1529                 if (!(off & 0x80000000))
1530                         continue;
1531                 off = off & 0x7fffffff;
1532                 check_pack_index_ptr(p, &idx2[off * 2]);
1533                 if (idx2[off * 2])
1534                         continue;
1535                 /*
1536                  * The real offset is ntohl(idx2[off * 2]) in high 4
1537                  * octets, and ntohl(idx2[off * 2 + 1]) in low 4
1538                  * octets.  But idx2[off * 2] is Zero!!!
1539                  */
1540                 ALLOC_GROW(opts->anomaly, opts->anomaly_nr + 1, opts->anomaly_alloc);
1541                 opts->anomaly[opts->anomaly_nr++] = ntohl(idx2[off * 2 + 1]);
1542         }
1543
1544         QSORT(opts->anomaly, opts->anomaly_nr, cmp_uint32);
1545 }
1546
1547 static void read_idx_option(struct pack_idx_option *opts, const char *pack_name)
1548 {
1549         struct packed_git *p = add_packed_git(pack_name, strlen(pack_name), 1);
1550
1551         if (!p)
1552                 die(_("Cannot open existing pack file '%s'"), pack_name);
1553         if (open_pack_index(p))
1554                 die(_("Cannot open existing pack idx file for '%s'"), pack_name);
1555
1556         /* Read the attributes from the existing idx file */
1557         opts->version = p->index_version;
1558
1559         if (opts->version == 2)
1560                 read_v2_anomalous_offsets(p, opts);
1561
1562         /*
1563          * Get rid of the idx file as we do not need it anymore.
1564          * NEEDSWORK: extract this bit from free_pack_by_name() in
1565          * sha1_file.c, perhaps?  It shouldn't matter very much as we
1566          * know we haven't installed this pack (hence we never have
1567          * read anything from it).
1568          */
1569         close_pack_index(p);
1570         free(p);
1571 }
1572
1573 static void show_pack_info(int stat_only)
1574 {
1575         int i, baseobjects = nr_objects - nr_ref_deltas - nr_ofs_deltas;
1576         unsigned long *chain_histogram = NULL;
1577
1578         if (deepest_delta)
1579                 chain_histogram = xcalloc(deepest_delta, sizeof(unsigned long));
1580
1581         for (i = 0; i < nr_objects; i++) {
1582                 struct object_entry *obj = &objects[i];
1583
1584                 if (is_delta_type(obj->type))
1585                         chain_histogram[obj_stat[i].delta_depth - 1]++;
1586                 if (stat_only)
1587                         continue;
1588                 printf("%s %-6s %lu %lu %"PRIuMAX,
1589                        oid_to_hex(&obj->idx.oid),
1590                        typename(obj->real_type), obj->size,
1591                        (unsigned long)(obj[1].idx.offset - obj->idx.offset),
1592                        (uintmax_t)obj->idx.offset);
1593                 if (is_delta_type(obj->type)) {
1594                         struct object_entry *bobj = &objects[obj_stat[i].base_object_no];
1595                         printf(" %u %s", obj_stat[i].delta_depth,
1596                                oid_to_hex(&bobj->idx.oid));
1597                 }
1598                 putchar('\n');
1599         }
1600
1601         if (baseobjects)
1602                 printf_ln(Q_("non delta: %d object",
1603                              "non delta: %d objects",
1604                              baseobjects),
1605                           baseobjects);
1606         for (i = 0; i < deepest_delta; i++) {
1607                 if (!chain_histogram[i])
1608                         continue;
1609                 printf_ln(Q_("chain length = %d: %lu object",
1610                              "chain length = %d: %lu objects",
1611                              chain_histogram[i]),
1612                           i + 1,
1613                           chain_histogram[i]);
1614         }
1615 }
1616
1617 static const char *derive_filename(const char *pack_name, const char *suffix,
1618                                    struct strbuf *buf)
1619 {
1620         size_t len;
1621         if (!strip_suffix(pack_name, ".pack", &len))
1622                 die(_("packfile name '%s' does not end with '.pack'"),
1623                     pack_name);
1624         strbuf_add(buf, pack_name, len);
1625         strbuf_addstr(buf, suffix);
1626         return buf->buf;
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_name = NULL, *keep_msg = NULL;
1635         struct strbuf index_name_buf = STRBUF_INIT,
1636                       keep_name_buf = STRBUF_INIT;
1637         struct pack_idx_entry **idx_objects;
1638         struct pack_idx_option opts;
1639         unsigned char pack_sha1[20];
1640         unsigned foreign_nr = 1;        /* zero is a "good" value, assume bad */
1641         int report_end_of_input = 0;
1642
1643         if (argc == 2 && !strcmp(argv[1], "-h"))
1644                 usage(index_pack_usage);
1645
1646         check_replace_refs = 0;
1647         fsck_options.walk = mark_link;
1648
1649         reset_pack_idx_option(&opts);
1650         git_config(git_index_pack_config, &opts);
1651         if (prefix && chdir(prefix))
1652                 die(_("Cannot come back to cwd"));
1653
1654         for (i = 1; i < argc; i++) {
1655                 const char *arg = argv[i];
1656
1657                 if (*arg == '-') {
1658                         if (!strcmp(arg, "--stdin")) {
1659                                 from_stdin = 1;
1660                         } else if (!strcmp(arg, "--fix-thin")) {
1661                                 fix_thin_pack = 1;
1662                         } else if (!strcmp(arg, "--strict")) {
1663                                 strict = 1;
1664                                 do_fsck_object = 1;
1665                         } else if (skip_prefix(arg, "--strict=", &arg)) {
1666                                 strict = 1;
1667                                 do_fsck_object = 1;
1668                                 fsck_set_msg_types(&fsck_options, arg);
1669                         } else if (!strcmp(arg, "--check-self-contained-and-connected")) {
1670                                 strict = 1;
1671                                 check_self_contained_and_connected = 1;
1672                         } else if (!strcmp(arg, "--verify")) {
1673                                 verify = 1;
1674                         } else if (!strcmp(arg, "--verify-stat")) {
1675                                 verify = 1;
1676                                 show_stat = 1;
1677                         } else if (!strcmp(arg, "--verify-stat-only")) {
1678                                 verify = 1;
1679                                 show_stat = 1;
1680                                 stat_only = 1;
1681                         } else if (!strcmp(arg, "--keep")) {
1682                                 keep_msg = "";
1683                         } else if (starts_with(arg, "--keep=")) {
1684                                 keep_msg = arg + 7;
1685                         } else if (starts_with(arg, "--threads=")) {
1686                                 char *end;
1687                                 nr_threads = strtoul(arg+10, &end, 0);
1688                                 if (!arg[10] || *end || nr_threads < 0)
1689                                         usage(index_pack_usage);
1690 #ifdef NO_PTHREADS
1691                                 if (nr_threads != 1)
1692                                         warning(_("no threads support, "
1693                                                   "ignoring %s"), arg);
1694                                 nr_threads = 1;
1695 #endif
1696                         } else if (starts_with(arg, "--pack_header=")) {
1697                                 struct pack_header *hdr;
1698                                 char *c;
1699
1700                                 hdr = (struct pack_header *)input_buffer;
1701                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
1702                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
1703                                 if (*c != ',')
1704                                         die(_("bad %s"), arg);
1705                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
1706                                 if (*c)
1707                                         die(_("bad %s"), arg);
1708                                 input_len = sizeof(*hdr);
1709                         } else if (!strcmp(arg, "-v")) {
1710                                 verbose = 1;
1711                         } else if (!strcmp(arg, "--show-resolving-progress")) {
1712                                 show_resolving_progress = 1;
1713                         } else if (!strcmp(arg, "--report-end-of-input")) {
1714                                 report_end_of_input = 1;
1715                         } else if (!strcmp(arg, "-o")) {
1716                                 if (index_name || (i+1) >= argc)
1717                                         usage(index_pack_usage);
1718                                 index_name = argv[++i];
1719                         } else if (starts_with(arg, "--index-version=")) {
1720                                 char *c;
1721                                 opts.version = strtoul(arg + 16, &c, 10);
1722                                 if (opts.version > 2)
1723                                         die(_("bad %s"), arg);
1724                                 if (*c == ',')
1725                                         opts.off32_limit = strtoul(c+1, &c, 0);
1726                                 if (*c || opts.off32_limit & 0x80000000)
1727                                         die(_("bad %s"), arg);
1728                         } else if (skip_prefix(arg, "--max-input-size=", &arg)) {
1729                                 max_input_size = strtoumax(arg, NULL, 10);
1730                         } else
1731                                 usage(index_pack_usage);
1732                         continue;
1733                 }
1734
1735                 if (pack_name)
1736                         usage(index_pack_usage);
1737                 pack_name = arg;
1738         }
1739
1740         if (!pack_name && !from_stdin)
1741                 usage(index_pack_usage);
1742         if (fix_thin_pack && !from_stdin)
1743                 die(_("--fix-thin cannot be used without --stdin"));
1744         if (from_stdin && !startup_info->have_repository)
1745                 die(_("--stdin requires a git repository"));
1746         if (!index_name && pack_name)
1747                 index_name = derive_filename(pack_name, ".idx", &index_name_buf);
1748         if (keep_msg && !keep_name && pack_name)
1749                 keep_name = derive_filename(pack_name, ".keep", &keep_name_buf);
1750
1751         if (verify) {
1752                 if (!index_name)
1753                         die(_("--verify with no packfile name given"));
1754                 read_idx_option(&opts, index_name);
1755                 opts.flags |= WRITE_IDX_VERIFY | WRITE_IDX_STRICT;
1756         }
1757         if (strict)
1758                 opts.flags |= WRITE_IDX_STRICT;
1759
1760 #ifndef NO_PTHREADS
1761         if (!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 #endif
1768
1769         curr_pack = open_pack_file(pack_name);
1770         parse_pack_header();
1771         objects = xcalloc(st_add(nr_objects, 1), sizeof(struct object_entry));
1772         if (show_stat)
1773                 obj_stat = xcalloc(st_add(nr_objects, 1), sizeof(struct object_stat));
1774         ofs_deltas = xcalloc(nr_objects, sizeof(struct ofs_delta_entry));
1775         parse_pack_objects(pack_sha1);
1776         if (report_end_of_input)
1777                 write_in_full(2, "\0", 1);
1778         resolve_deltas();
1779         conclude_pack(fix_thin_pack, curr_pack, pack_sha1);
1780         free(ofs_deltas);
1781         free(ref_deltas);
1782         if (strict)
1783                 foreign_nr = check_objects();
1784
1785         if (show_stat)
1786                 show_pack_info(stat_only);
1787
1788         ALLOC_ARRAY(idx_objects, nr_objects);
1789         for (i = 0; i < nr_objects; i++)
1790                 idx_objects[i] = &objects[i].idx;
1791         curr_index = write_idx_file(index_name, idx_objects, nr_objects, &opts, pack_sha1);
1792         free(idx_objects);
1793
1794         if (!verify)
1795                 final(pack_name, curr_pack,
1796                       index_name, curr_index,
1797                       keep_name, keep_msg,
1798                       pack_sha1);
1799         else
1800                 close(input_fd);
1801         free(objects);
1802         strbuf_release(&index_name_buf);
1803         strbuf_release(&keep_name_buf);
1804         if (pack_name == NULL)
1805                 free((void *) curr_pack);
1806         if (index_name == NULL)
1807                 free((void *) curr_index);
1808
1809         /*
1810          * Let the caller know this pack is not self contained
1811          */
1812         if (check_self_contained_and_connected && foreign_nr)
1813                 return 1;
1814
1815         return 0;
1816 }