builtin/index-pack.c

   1 #include "builtin.h"
   2 #include "config.h"
   3 #include "delta.h"
   4 #include "pack.h"
   5 #include "csum-file.h"
   6 #include "blob.h"
   7 #include "commit.h"
   8 #include "tag.h"
   9 #include "tree.h"
  10 #include "progress.h"
  11 #include "fsck.h"
  12 #include "exec-cmd.h"
  13 #include "streaming.h"
  14 #include "thread-utils.h"
  15 #include "packfile.h"
  16 #include "object-store.h"
  17 #include "promisor-remote.h"
  18
  19 static const char index_pack_usage[] =
  20 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--[no-]rev-index] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
  21
  22 struct object_entry {
  23         struct pack_idx_entry idx;
  24         unsigned long size;
  25         unsigned char hdr_size;
  26         signed char type;
  27         signed char real_type;
  28 };
  29
  30 struct object_stat {
  31         unsigned delta_depth;
  32         int base_object_no;
  33 };
  34
  35 struct base_data {
  36         /* Initialized by make_base(). */
  37         struct base_data *base;
  38         struct object_entry *obj;
  39         int ref_first, ref_last;
  40         int ofs_first, ofs_last;
  41         /*
  42          * Threads should increment retain_data if they are about to call
  43          * patch_delta() using this struct's data as a base, and decrement this
  44          * when they are done. While retain_data is nonzero, this struct's data
  45          * will not be freed even if the delta base cache limit is exceeded.
  46          */
  47         int retain_data;
  48         /*
  49          * The number of direct children that have not been fully processed
  50          * (entered work_head, entered done_head, left done_head). When this
  51          * number reaches zero, this struct base_data can be freed.
  52          */
  53         int children_remaining;
  54
  55         /* Not initialized by make_base(). */
  56         struct list_head list;
  57         void *data;
  58         unsigned long size;
  59 };
  60
  61 /*
  62  * Stack of struct base_data that have unprocessed children.
  63  * threaded_second_pass() uses this as a source of work (the other being the
  64  * objects array).
  65  *
  66  * Guarded by work_mutex.
  67  */
  68 static LIST_HEAD(work_head);
  69
  70 /*
  71  * Stack of struct base_data that have children, all of whom have been
  72  * processed or are being processed, and at least one child is being processed.
  73  * These struct base_data must be kept around until the last child is
  74  * processed.
  75  *
  76  * Guarded by work_mutex.
  77  */
  78 static LIST_HEAD(done_head);
  79
  80 /*
  81  * All threads share one delta base cache.
  82  *
  83  * base_cache_used is guarded by work_mutex, and base_cache_limit is read-only
  84  * in a thread.
  85  */
  86 static size_t base_cache_used;
  87 static size_t base_cache_limit;
  88
  89 struct thread_local {
  90         pthread_t thread;
  91         int pack_fd;
  92 };
  93
  94 /* Remember to update object flag allocation in object.h */
  95 #define FLAG_LINK (1u<<20)
  96 #define FLAG_CHECKED (1u<<21)
  97
  98 struct ofs_delta_entry {
  99         off_t offset;
 100         int obj_no;
 101 };
 102
 103 struct ref_delta_entry {
 104         struct object_id oid;
 105         int obj_no;
 106 };
 107
 108 static struct object_entry *objects;
 109 static struct object_stat *obj_stat;
 110 static struct ofs_delta_entry *ofs_deltas;
 111 static struct ref_delta_entry *ref_deltas;
 112 static struct thread_local nothread_data;
 113 static int nr_objects;
 114 static int nr_ofs_deltas;
 115 static int nr_ref_deltas;
 116 static int ref_deltas_alloc;
 117 static int nr_resolved_deltas;
 118 static int nr_threads;
 119
 120 static int from_stdin;
 121 static int strict;
 122 static int do_fsck_object;
 123 static struct fsck_options fsck_options = FSCK_OPTIONS_MISSING_GITMODULES;
 124 static int verbose;
 125 static const char *progress_title;
 126 static int show_resolving_progress;
 127 static int show_stat;
 128 static int check_self_contained_and_connected;
 129
 130 static struct progress *progress;
 131
 132 /* We always read in 4kB chunks. */
 133 static unsigned char input_buffer[4096];
 134 static unsigned int input_offset, input_len;
 135 static off_t consumed_bytes;
 136 static off_t max_input_size;
 137 static unsigned deepest_delta;
 138 static git_hash_ctx input_ctx;
 139 static uint32_t input_crc32;
 140 static int input_fd, output_fd;
 141 static const char *curr_pack;
 142
 143 static struct thread_local *thread_data;
 144 static int nr_dispatched;
 145 static int threads_active;
 146
 147 static pthread_mutex_t read_mutex;
 148 #define read_lock()             lock_mutex(&read_mutex)
 149 #define read_unlock()           unlock_mutex(&read_mutex)
 150
 151 static pthread_mutex_t counter_mutex;
 152 #define counter_lock()          lock_mutex(&counter_mutex)
 153 #define counter_unlock()        unlock_mutex(&counter_mutex)
 154
 155 static pthread_mutex_t work_mutex;
 156 #define work_lock()             lock_mutex(&work_mutex)
 157 #define work_unlock()           unlock_mutex(&work_mutex)
 158
 159 static pthread_mutex_t deepest_delta_mutex;
 160 #define deepest_delta_lock()    lock_mutex(&deepest_delta_mutex)
 161 #define deepest_delta_unlock()  unlock_mutex(&deepest_delta_mutex)
 162
 163 static pthread_key_t key;
 164
 165 static inline void lock_mutex(pthread_mutex_t *mutex)
 166 {
 167         if (threads_active)
 168                 pthread_mutex_lock(mutex);
 169 }
 170
 171 static inline void unlock_mutex(pthread_mutex_t *mutex)
 172 {
 173         if (threads_active)
 174                 pthread_mutex_unlock(mutex);
 175 }
 176
 177 /*
 178  * Mutex and conditional variable can't be statically-initialized on Windows.
 179  */
 180 static void init_thread(void)
 181 {
 182         int i;
 183         init_recursive_mutex(&read_mutex);
 184         pthread_mutex_init(&counter_mutex, NULL);
 185         pthread_mutex_init(&work_mutex, NULL);
 186         if (show_stat)
 187                 pthread_mutex_init(&deepest_delta_mutex, NULL);
 188         pthread_key_create(&key, NULL);
 189         CALLOC_ARRAY(thread_data, nr_threads);
 190         for (i = 0; i < nr_threads; i++) {
 191                 thread_data[i].pack_fd = xopen(curr_pack, O_RDONLY);
 192         }
 193
 194         threads_active = 1;
 195 }
 196
 197 static void cleanup_thread(void)
 198 {
 199         int i;
 200         if (!threads_active)
 201                 return;
 202         threads_active = 0;
 203         pthread_mutex_destroy(&read_mutex);
 204         pthread_mutex_destroy(&counter_mutex);
 205         pthread_mutex_destroy(&work_mutex);
 206         if (show_stat)
 207                 pthread_mutex_destroy(&deepest_delta_mutex);
 208         for (i = 0; i < nr_threads; i++)
 209                 close(thread_data[i].pack_fd);
 210         pthread_key_delete(key);
 211         free(thread_data);
 212 }
 213
 214 static int mark_link(struct object *obj, enum object_type type,
 215                      void *data, struct fsck_options *options)
 216 {
 217         if (!obj)
 218                 return -1;
 219
 220         if (type != OBJ_ANY && obj->type != type)
 221                 die(_("object type mismatch at %s"), oid_to_hex(&obj->oid));
 222
 223         obj->flags |= FLAG_LINK;
 224         return 0;
 225 }
 226
 227 /* The content of each linked object must have been checked
 228    or it must be already present in the object database */
 229 static unsigned check_object(struct object *obj)
 230 {
 231         if (!obj)
 232                 return 0;
 233
 234         if (!(obj->flags & FLAG_LINK))
 235                 return 0;
 236
 237         if (!(obj->flags & FLAG_CHECKED)) {
 238                 unsigned long size;
 239                 int type = oid_object_info(the_repository, &obj->oid, &size);
 240                 if (type <= 0)
 241                         die(_("did not receive expected object %s"),
 242                               oid_to_hex(&obj->oid));
 243                 if (type != obj->type)
 244                         die(_("object %s: expected type %s, found %s"),
 245                             oid_to_hex(&obj->oid),
 246                             type_name(obj->type), type_name(type));
 247                 obj->flags |= FLAG_CHECKED;
 248                 return 1;
 249         }
 250
 251         return 0;
 252 }
 253
 254 static unsigned check_objects(void)
 255 {
 256         unsigned i, max, foreign_nr = 0;
 257
 258         max = get_max_object_index();
 259
 260         if (verbose)
 261                 progress = start_delayed_progress(_("Checking objects"), max);
 262
 263         for (i = 0; i < max; i++) {
 264                 foreign_nr += check_object(get_indexed_object(i));
 265                 display_progress(progress, i + 1);
 266         }
 267
 268         stop_progress(&progress);
 269         return foreign_nr;
 270 }
 271
 272
 273 /* Discard current buffer used content. */
 274 static void flush(void)
 275 {
 276         if (input_offset) {
 277                 if (output_fd >= 0)
 278                         write_or_die(output_fd, input_buffer, input_offset);
 279                 the_hash_algo->update_fn(&input_ctx, input_buffer, input_offset);
 280                 memmove(input_buffer, input_buffer + input_offset, input_len);
 281                 input_offset = 0;
 282         }
 283 }
 284
 285 /*
 286  * Make sure at least "min" bytes are available in the buffer, and
 287  * return the pointer to the buffer.
 288  */
 289 static void *fill(int min)
 290 {
 291         if (min <= input_len)
 292                 return input_buffer + input_offset;
 293         if (min > sizeof(input_buffer))
 294                 die(Q_("cannot fill %d byte",
 295                        "cannot fill %d bytes",
 296                        min),
 297                     min);
 298         flush();
 299         do {
 300                 ssize_t ret = xread(input_fd, input_buffer + input_len,
 301                                 sizeof(input_buffer) - input_len);
 302                 if (ret <= 0) {
 303                         if (!ret)
 304                                 die(_("early EOF"));
 305                         die_errno(_("read error on input"));
 306                 }
 307                 input_len += ret;
 308                 if (from_stdin)
 309                         display_throughput(progress, consumed_bytes + input_len);
 310         } while (input_len < min);
 311         return input_buffer;
 312 }
 313
 314 static void use(int bytes)
 315 {
 316         if (bytes > input_len)
 317                 die(_("used more bytes than were available"));
 318         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 319         input_len -= bytes;
 320         input_offset += bytes;
 321
 322         /* make sure off_t is sufficiently large not to wrap */
 323         if (signed_add_overflows(consumed_bytes, bytes))
 324                 die(_("pack too large for current definition of off_t"));
 325         consumed_bytes += bytes;
 326         if (max_input_size && consumed_bytes > max_input_size) {
 327                 struct strbuf size_limit = STRBUF_INIT;
 328                 strbuf_humanise_bytes(&size_limit, max_input_size);
 329                 die(_("pack exceeds maximum allowed size (%s)"),
 330                     size_limit.buf);
 331         }
 332 }
 333
 334 static const char *open_pack_file(const char *pack_name)
 335 {
 336         if (from_stdin) {
 337                 input_fd = 0;
 338                 if (!pack_name) {
 339                         struct strbuf tmp_file = STRBUF_INIT;
 340                         output_fd = odb_mkstemp(&tmp_file,
 341                                                 "pack/tmp_pack_XXXXXX");
 342                         pack_name = strbuf_detach(&tmp_file, NULL);
 343                 } else {
 344                         output_fd = xopen(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 345                 }
 346                 nothread_data.pack_fd = output_fd;
 347         } else {
 348                 input_fd = xopen(pack_name, O_RDONLY);
 349                 output_fd = -1;
 350                 nothread_data.pack_fd = input_fd;
 351         }
 352         the_hash_algo->init_fn(&input_ctx);
 353         return pack_name;
 354 }
 355
 356 static void parse_pack_header(void)
 357 {
 358         struct pack_header *hdr = fill(sizeof(struct pack_header));
 359
 360         /* Header consistency check */
 361         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 362                 die(_("pack signature mismatch"));
 363         if (!pack_version_ok(hdr->hdr_version))
 364                 die(_("pack version %"PRIu32" unsupported"),
 365                         ntohl(hdr->hdr_version));
 366
 367         nr_objects = ntohl(hdr->hdr_entries);
 368         use(sizeof(struct pack_header));
 369 }
 370
 371 __attribute__((format (printf, 2, 3)))
 372 static NORETURN void bad_object(off_t offset, const char *format, ...)
 373 {
 374         va_list params;
 375         char buf[1024];
 376
 377         va_start(params, format);
 378         vsnprintf(buf, sizeof(buf), format, params);
 379         va_end(params);
 380         die(_("pack has bad object at offset %"PRIuMAX": %s"),
 381             (uintmax_t)offset, buf);
 382 }
 383
 384 static inline struct thread_local *get_thread_data(void)
 385 {
 386         if (HAVE_THREADS) {
 387                 if (threads_active)
 388                         return pthread_getspecific(key);
 389                 assert(!threads_active &&
 390                        "This should only be reached when all threads are gone");
 391         }
 392         return &nothread_data;
 393 }
 394
 395 static void set_thread_data(struct thread_local *data)
 396 {
 397         if (threads_active)
 398                 pthread_setspecific(key, data);
 399 }
 400
 401 static void free_base_data(struct base_data *c)
 402 {
 403         if (c->data) {
 404                 FREE_AND_NULL(c->data);
 405                 base_cache_used -= c->size;
 406         }
 407 }
 408
 409 static void prune_base_data(struct base_data *retain)
 410 {
 411         struct list_head *pos;
 412
 413         if (base_cache_used <= base_cache_limit)
 414                 return;
 415
 416         list_for_each_prev(pos, &done_head) {
 417                 struct base_data *b = list_entry(pos, struct base_data, list);
 418                 if (b->retain_data || b == retain)
 419                         continue;
 420                 if (b->data) {
 421                         free_base_data(b);
 422                         if (base_cache_used <= base_cache_limit)
 423                                 return;
 424                 }
 425         }
 426
 427         list_for_each_prev(pos, &work_head) {
 428                 struct base_data *b = list_entry(pos, struct base_data, list);
 429                 if (b->retain_data || b == retain)
 430                         continue;
 431                 if (b->data) {
 432                         free_base_data(b);
 433                         if (base_cache_used <= base_cache_limit)
 434                                 return;
 435                 }
 436         }
 437 }
 438
 439 static int is_delta_type(enum object_type type)
 440 {
 441         return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
 442 }
 443
 444 static void *unpack_entry_data(off_t offset, unsigned long size,
 445                                enum object_type type, struct object_id *oid)
 446 {
 447         static char fixed_buf[8192];
 448         int status;
 449         git_zstream stream;
 450         void *buf;
 451         git_hash_ctx c;
 452         char hdr[32];
 453         int hdrlen;
 454
 455         if (!is_delta_type(type)) {
 456                 hdrlen = format_object_header(hdr, sizeof(hdr), type, size);
 457                 the_hash_algo->init_fn(&c);
 458                 the_hash_algo->update_fn(&c, hdr, hdrlen);
 459         } else
 460                 oid = NULL;
 461         if (type == OBJ_BLOB && size > big_file_threshold)
 462                 buf = fixed_buf;
 463         else
 464                 buf = xmallocz(size);
 465
 466         memset(&stream, 0, sizeof(stream));
 467         git_inflate_init(&stream);
 468         stream.next_out = buf;
 469         stream.avail_out = buf == fixed_buf ? sizeof(fixed_buf) : size;
 470
 471         do {
 472                 unsigned char *last_out = stream.next_out;
 473                 stream.next_in = fill(1);
 474                 stream.avail_in = input_len;
 475                 status = git_inflate(&stream, 0);
 476                 use(input_len - stream.avail_in);
 477                 if (oid)
 478                         the_hash_algo->update_fn(&c, last_out, stream.next_out - last_out);
 479                 if (buf == fixed_buf) {
 480                         stream.next_out = buf;
 481                         stream.avail_out = sizeof(fixed_buf);
 482                 }
 483         } while (status == Z_OK);
 484         if (stream.total_out != size || status != Z_STREAM_END)
 485                 bad_object(offset, _("inflate returned %d"), status);
 486         git_inflate_end(&stream);
 487         if (oid)
 488                 the_hash_algo->final_oid_fn(oid, &c);
 489         return buf == fixed_buf ? NULL : buf;
 490 }
 491
 492 static void *unpack_raw_entry(struct object_entry *obj,
 493                               off_t *ofs_offset,
 494                               struct object_id *ref_oid,
 495                               struct object_id *oid)
 496 {
 497         unsigned char *p;
 498         unsigned long size, c;
 499         off_t base_offset;
 500         unsigned shift;
 501         void *data;
 502
 503         obj->idx.offset = consumed_bytes;
 504         input_crc32 = crc32(0, NULL, 0);
 505
 506         p = fill(1);
 507         c = *p;
 508         use(1);
 509         obj->type = (c >> 4) & 7;
 510         size = (c & 15);
 511         shift = 4;
 512         while (c & 0x80) {
 513                 p = fill(1);
 514                 c = *p;
 515                 use(1);
 516                 size += (c & 0x7f) << shift;
 517                 shift += 7;
 518         }
 519         obj->size = size;
 520
 521         switch (obj->type) {
 522         case OBJ_REF_DELTA:
 523                 oidread(ref_oid, fill(the_hash_algo->rawsz));
 524                 use(the_hash_algo->rawsz);
 525                 break;
 526         case OBJ_OFS_DELTA:
 527                 p = fill(1);
 528                 c = *p;
 529                 use(1);
 530                 base_offset = c & 127;
 531                 while (c & 128) {
 532                         base_offset += 1;
 533                         if (!base_offset || MSB(base_offset, 7))
 534                                 bad_object(obj->idx.offset, _("offset value overflow for delta base object"));
 535                         p = fill(1);
 536                         c = *p;
 537                         use(1);
 538                         base_offset = (base_offset << 7) + (c & 127);
 539                 }
 540                 *ofs_offset = obj->idx.offset - base_offset;
 541                 if (*ofs_offset <= 0 || *ofs_offset >= obj->idx.offset)
 542                         bad_object(obj->idx.offset, _("delta base offset is out of bound"));
 543                 break;
 544         case OBJ_COMMIT:
 545         case OBJ_TREE:
 546         case OBJ_BLOB:
 547         case OBJ_TAG:
 548                 break;
 549         default:
 550                 bad_object(obj->idx.offset, _("unknown object type %d"), obj->type);
 551         }
 552         obj->hdr_size = consumed_bytes - obj->idx.offset;
 553
 554         data = unpack_entry_data(obj->idx.offset, obj->size, obj->type, oid);
 555         obj->idx.crc32 = input_crc32;
 556         return data;
 557 }
 558
 559 static void *unpack_data(struct object_entry *obj,
 560                          int (*consume)(const unsigned char *, unsigned long, void *),
 561                          void *cb_data)
 562 {
 563         off_t from = obj[0].idx.offset + obj[0].hdr_size;
 564         off_t len = obj[1].idx.offset - from;
 565         unsigned char *data, *inbuf;
 566         git_zstream stream;
 567         int status;
 568
 569         data = xmallocz(consume ? 64*1024 : obj->size);
 570         inbuf = xmalloc((len < 64*1024) ? (int)len : 64*1024);
 571
 572         memset(&stream, 0, sizeof(stream));
 573         git_inflate_init(&stream);
 574         stream.next_out = data;
 575         stream.avail_out = consume ? 64*1024 : obj->size;
 576
 577         do {
 578                 ssize_t n = (len < 64*1024) ? (ssize_t)len : 64*1024;
 579                 n = xpread(get_thread_data()->pack_fd, inbuf, n, from);
 580                 if (n < 0)
 581                         die_errno(_("cannot pread pack file"));
 582                 if (!n)
 583                         die(Q_("premature end of pack file, %"PRIuMAX" byte missing",
 584                                "premature end of pack file, %"PRIuMAX" bytes missing",
 585                                len),
 586                             (uintmax_t)len);
 587                 from += n;
 588                 len -= n;
 589                 stream.next_in = inbuf;
 590                 stream.avail_in = n;
 591                 if (!consume)
 592                         status = git_inflate(&stream, 0);
 593                 else {
 594                         do {
 595                                 status = git_inflate(&stream, 0);
 596                                 if (consume(data, stream.next_out - data, cb_data)) {
 597                                         free(inbuf);
 598                                         free(data);
 599                                         return NULL;
 600                                 }
 601                                 stream.next_out = data;
 602                                 stream.avail_out = 64*1024;
 603                         } while (status == Z_OK && stream.avail_in);
 604                 }
 605         } while (len && status == Z_OK && !stream.avail_in);
 606
 607         /* This has been inflated OK when first encountered, so... */
 608         if (status != Z_STREAM_END || stream.total_out != obj->size)
 609                 die(_("serious inflate inconsistency"));
 610
 611         git_inflate_end(&stream);
 612         free(inbuf);
 613         if (consume) {
 614                 FREE_AND_NULL(data);
 615         }
 616         return data;
 617 }
 618
 619 static void *get_data_from_pack(struct object_entry *obj)
 620 {
 621         return unpack_data(obj, NULL, NULL);
 622 }
 623
 624 static int compare_ofs_delta_bases(off_t offset1, off_t offset2,
 625                                    enum object_type type1,
 626                                    enum object_type type2)
 627 {
 628         int cmp = type1 - type2;
 629         if (cmp)
 630                 return cmp;
 631         return offset1 < offset2 ? -1 :
 632                offset1 > offset2 ?  1 :
 633                0;
 634 }
 635
 636 static int find_ofs_delta(const off_t offset)
 637 {
 638         int first = 0, last = nr_ofs_deltas;
 639
 640         while (first < last) {
 641                 int next = first + (last - first) / 2;
 642                 struct ofs_delta_entry *delta = &ofs_deltas[next];
 643                 int cmp;
 644
 645                 cmp = compare_ofs_delta_bases(offset, delta->offset,
 646                                               OBJ_OFS_DELTA,
 647                                               objects[delta->obj_no].type);
 648                 if (!cmp)
 649                         return next;
 650                 if (cmp < 0) {
 651                         last = next;
 652                         continue;
 653                 }
 654                 first = next+1;
 655         }
 656         return -first-1;
 657 }
 658
 659 static void find_ofs_delta_children(off_t offset,
 660                                     int *first_index, int *last_index)
 661 {
 662         int first = find_ofs_delta(offset);
 663         int last = first;
 664         int end = nr_ofs_deltas - 1;
 665
 666         if (first < 0) {
 667                 *first_index = 0;
 668                 *last_index = -1;
 669                 return;
 670         }
 671         while (first > 0 && ofs_deltas[first - 1].offset == offset)
 672                 --first;
 673         while (last < end && ofs_deltas[last + 1].offset == offset)
 674                 ++last;
 675         *first_index = first;
 676         *last_index = last;
 677 }
 678
 679 static int compare_ref_delta_bases(const struct object_id *oid1,
 680                                    const struct object_id *oid2,
 681                                    enum object_type type1,
 682                                    enum object_type type2)
 683 {
 684         int cmp = type1 - type2;
 685         if (cmp)
 686                 return cmp;
 687         return oidcmp(oid1, oid2);
 688 }
 689
 690 static int find_ref_delta(const struct object_id *oid)
 691 {
 692         int first = 0, last = nr_ref_deltas;
 693
 694         while (first < last) {
 695                 int next = first + (last - first) / 2;
 696                 struct ref_delta_entry *delta = &ref_deltas[next];
 697                 int cmp;
 698
 699                 cmp = compare_ref_delta_bases(oid, &delta->oid,
 700                                               OBJ_REF_DELTA,
 701                                               objects[delta->obj_no].type);
 702                 if (!cmp)
 703                         return next;
 704                 if (cmp < 0) {
 705                         last = next;
 706                         continue;
 707                 }
 708                 first = next+1;
 709         }
 710         return -first-1;
 711 }
 712
 713 static void find_ref_delta_children(const struct object_id *oid,
 714                                     int *first_index, int *last_index)
 715 {
 716         int first = find_ref_delta(oid);
 717         int last = first;
 718         int end = nr_ref_deltas - 1;
 719
 720         if (first < 0) {
 721                 *first_index = 0;
 722                 *last_index = -1;
 723                 return;
 724         }
 725         while (first > 0 && oideq(&ref_deltas[first - 1].oid, oid))
 726                 --first;
 727         while (last < end && oideq(&ref_deltas[last + 1].oid, oid))
 728                 ++last;
 729         *first_index = first;
 730         *last_index = last;
 731 }
 732
 733 struct compare_data {
 734         struct object_entry *entry;
 735         struct git_istream *st;
 736         unsigned char *buf;
 737         unsigned long buf_size;
 738 };
 739
 740 static int compare_objects(const unsigned char *buf, unsigned long size,
 741                            void *cb_data)
 742 {
 743         struct compare_data *data = cb_data;
 744
 745         if (data->buf_size < size) {
 746                 free(data->buf);
 747                 data->buf = xmalloc(size);
 748                 data->buf_size = size;
 749         }
 750
 751         while (size) {
 752                 ssize_t len = read_istream(data->st, data->buf, size);
 753                 if (len == 0)
 754                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 755                             oid_to_hex(&data->entry->idx.oid));
 756                 if (len < 0)
 757                         die(_("unable to read %s"),
 758                             oid_to_hex(&data->entry->idx.oid));
 759                 if (memcmp(buf, data->buf, len))
 760                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 761                             oid_to_hex(&data->entry->idx.oid));
 762                 size -= len;
 763                 buf += len;
 764         }
 765         return 0;
 766 }
 767
 768 static int check_collison(struct object_entry *entry)
 769 {
 770         struct compare_data data;
 771         enum object_type type;
 772         unsigned long size;
 773
 774         if (entry->size <= big_file_threshold || entry->type != OBJ_BLOB)
 775                 return -1;
 776
 777         memset(&data, 0, sizeof(data));
 778         data.entry = entry;
 779         data.st = open_istream(the_repository, &entry->idx.oid, &type, &size,
 780                                NULL);
 781         if (!data.st)
 782                 return -1;
 783         if (size != entry->size || type != entry->type)
 784                 die(_("SHA1 COLLISION FOUND WITH %s !"),
 785                     oid_to_hex(&entry->idx.oid));
 786         unpack_data(entry, compare_objects, &data);
 787         close_istream(data.st);
 788         free(data.buf);
 789         return 0;
 790 }
 791
 792 static void sha1_object(const void *data, struct object_entry *obj_entry,
 793                         unsigned long size, enum object_type type,
 794                         const struct object_id *oid)
 795 {
 796         void *new_data = NULL;
 797         int collision_test_needed = 0;
 798
 799         assert(data || obj_entry);
 800
 801         if (startup_info->have_repository) {
 802                 read_lock();
 803                 collision_test_needed =
 804                         has_object_file_with_flags(oid, OBJECT_INFO_QUICK);
 805                 read_unlock();
 806         }
 807
 808         if (collision_test_needed && !data) {
 809                 read_lock();
 810                 if (!check_collison(obj_entry))
 811                         collision_test_needed = 0;
 812                 read_unlock();
 813         }
 814         if (collision_test_needed) {
 815                 void *has_data;
 816                 enum object_type has_type;
 817                 unsigned long has_size;
 818                 read_lock();
 819                 has_type = oid_object_info(the_repository, oid, &has_size);
 820                 if (has_type < 0)
 821                         die(_("cannot read existing object info %s"), oid_to_hex(oid));
 822                 if (has_type != type || has_size != size)
 823                         die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
 824                 has_data = read_object_file(oid, &has_type, &has_size);
 825                 read_unlock();
 826                 if (!data)
 827                         data = new_data = get_data_from_pack(obj_entry);
 828                 if (!has_data)
 829                         die(_("cannot read existing object %s"), oid_to_hex(oid));
 830                 if (size != has_size || type != has_type ||
 831                     memcmp(data, has_data, size) != 0)
 832                         die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
 833                 free(has_data);
 834         }
 835
 836         if (strict || do_fsck_object) {
 837                 read_lock();
 838                 if (type == OBJ_BLOB) {
 839                         struct blob *blob = lookup_blob(the_repository, oid);
 840                         if (blob)
 841                                 blob->object.flags |= FLAG_CHECKED;
 842                         else
 843                                 die(_("invalid blob object %s"), oid_to_hex(oid));
 844                         if (do_fsck_object &&
 845                             fsck_object(&blob->object, (void *)data, size, &fsck_options))
 846                                 die(_("fsck error in packed object"));
 847                 } else {
 848                         struct object *obj;
 849                         int eaten;
 850                         void *buf = (void *) data;
 851
 852                         assert(data && "data can only be NULL for large _blobs_");
 853
 854                         /*
 855                          * we do not need to free the memory here, as the
 856                          * buf is deleted by the caller.
 857                          */
 858                         obj = parse_object_buffer(the_repository, oid, type,
 859                                                   size, buf,
 860                                                   &eaten);
 861                         if (!obj)
 862                                 die(_("invalid %s"), type_name(type));
 863                         if (do_fsck_object &&
 864                             fsck_object(obj, buf, size, &fsck_options))
 865                                 die(_("fsck error in packed object"));
 866                         if (strict && fsck_walk(obj, NULL, &fsck_options))
 867                                 die(_("Not all child objects of %s are reachable"), oid_to_hex(&obj->oid));
 868
 869                         if (obj->type == OBJ_TREE) {
 870                                 struct tree *item = (struct tree *) obj;
 871                                 item->buffer = NULL;
 872                                 obj->parsed = 0;
 873                         }
 874                         if (obj->type == OBJ_COMMIT) {
 875                                 struct commit *commit = (struct commit *) obj;
 876                                 if (detach_commit_buffer(commit, NULL) != data)
 877                                         BUG("parse_object_buffer transmogrified our buffer");
 878                         }
 879                         obj->flags |= FLAG_CHECKED;
 880                 }
 881                 read_unlock();
 882         }
 883
 884         free(new_data);
 885 }
 886
 887 /*
 888  * Ensure that this node has been reconstructed and return its contents.
 889  *
 890  * In the typical and best case, this node would already be reconstructed
 891  * (through the invocation to resolve_delta() in threaded_second_pass()) and it
 892  * would not be pruned. However, if pruning of this node was necessary due to
 893  * reaching delta_base_cache_limit, this function will find the closest
 894  * ancestor with reconstructed data that has not been pruned (or if there is
 895  * none, the ultimate base object), and reconstruct each node in the delta
 896  * chain in order to generate the reconstructed data for this node.
 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                         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                         base_cache_used += c->size;
 930                         prune_base_data(c);
 931                 }
 932                 free(delta);
 933         }
 934         return c->data;
 935 }
 936
 937 static struct base_data *make_base(struct object_entry *obj,
 938                                    struct base_data *parent)
 939 {
 940         struct base_data *base = xcalloc(1, sizeof(struct base_data));
 941         base->base = parent;
 942         base->obj = obj;
 943         find_ref_delta_children(&obj->idx.oid,
 944                                 &base->ref_first, &base->ref_last);
 945         find_ofs_delta_children(obj->idx.offset,
 946                                 &base->ofs_first, &base->ofs_last);
 947         base->children_remaining = base->ref_last - base->ref_first +
 948                 base->ofs_last - base->ofs_first + 2;
 949         return base;
 950 }
 951
 952 static struct base_data *resolve_delta(struct object_entry *delta_obj,
 953                                        struct base_data *base)
 954 {
 955         void *delta_data, *result_data;
 956         struct base_data *result;
 957         unsigned long result_size;
 958
 959         if (show_stat) {
 960                 int i = delta_obj - objects;
 961                 int j = base->obj - objects;
 962                 obj_stat[i].delta_depth = obj_stat[j].delta_depth + 1;
 963                 deepest_delta_lock();
 964                 if (deepest_delta < obj_stat[i].delta_depth)
 965                         deepest_delta = obj_stat[i].delta_depth;
 966                 deepest_delta_unlock();
 967                 obj_stat[i].base_object_no = j;
 968         }
 969         delta_data = get_data_from_pack(delta_obj);
 970         assert(base->data);
 971         result_data = patch_delta(base->data, base->size,
 972                                   delta_data, delta_obj->size, &result_size);
 973         free(delta_data);
 974         if (!result_data)
 975                 bad_object(delta_obj->idx.offset, _("failed to apply delta"));
 976         hash_object_file(the_hash_algo, result_data, result_size,
 977                          delta_obj->real_type, &delta_obj->idx.oid);
 978         sha1_object(result_data, NULL, result_size, delta_obj->real_type,
 979                     &delta_obj->idx.oid);
 980
 981         result = make_base(delta_obj, base);
 982         result->data = result_data;
 983         result->size = result_size;
 984
 985         counter_lock();
 986         nr_resolved_deltas++;
 987         counter_unlock();
 988
 989         return result;
 990 }
 991
 992 static int compare_ofs_delta_entry(const void *a, const void *b)
 993 {
 994         const struct ofs_delta_entry *delta_a = a;
 995         const struct ofs_delta_entry *delta_b = b;
 996
 997         return delta_a->offset < delta_b->offset ? -1 :
 998                delta_a->offset > delta_b->offset ?  1 :
 999                0;
1000 }
1001
1002 static int compare_ref_delta_entry(const void *a, const void *b)
1003 {
1004         const struct ref_delta_entry *delta_a = a;
1005         const struct ref_delta_entry *delta_b = b;
1006
1007         return oidcmp(&delta_a->oid, &delta_b->oid);
1008 }
1009
1010 static void *threaded_second_pass(void *data)
1011 {
1012         if (data)
1013                 set_thread_data(data);
1014         for (;;) {
1015                 struct base_data *parent = NULL;
1016                 struct object_entry *child_obj;
1017                 struct base_data *child;
1018
1019                 counter_lock();
1020                 display_progress(progress, nr_resolved_deltas);
1021                 counter_unlock();
1022
1023                 work_lock();
1024                 if (list_empty(&work_head)) {
1025                         /*
1026                          * Take an object from the object array.
1027                          */
1028                         while (nr_dispatched < nr_objects &&
1029                                is_delta_type(objects[nr_dispatched].type))
1030                                 nr_dispatched++;
1031                         if (nr_dispatched >= nr_objects) {
1032                                 work_unlock();
1033                                 break;
1034                         }
1035                         child_obj = &objects[nr_dispatched++];
1036                 } else {
1037                         /*
1038                          * Peek at the top of the stack, and take a child from
1039                          * it.
1040                          */
1041                         parent = list_first_entry(&work_head, struct base_data,
1042                                                   list);
1043
1044                         if (parent->ref_first <= parent->ref_last) {
1045                                 int offset = ref_deltas[parent->ref_first++].obj_no;
1046                                 child_obj = objects + offset;
1047                                 if (child_obj->real_type != OBJ_REF_DELTA)
1048                                         die("REF_DELTA at offset %"PRIuMAX" already resolved (duplicate base %s?)",
1049                                             (uintmax_t) child_obj->idx.offset,
1050                                             oid_to_hex(&parent->obj->idx.oid));
1051                                 child_obj->real_type = parent->obj->real_type;
1052                         } else {
1053                                 child_obj = objects +
1054                                         ofs_deltas[parent->ofs_first++].obj_no;
1055                                 assert(child_obj->real_type == OBJ_OFS_DELTA);
1056                                 child_obj->real_type = parent->obj->real_type;
1057                         }
1058
1059                         if (parent->ref_first > parent->ref_last &&
1060                             parent->ofs_first > parent->ofs_last) {
1061                                 /*
1062                                  * This parent has run out of children, so move
1063                                  * it to done_head.
1064                                  */
1065                                 list_del(&parent->list);
1066                                 list_add(&parent->list, &done_head);
1067                         }
1068
1069                         /*
1070                          * Ensure that the parent has data, since we will need
1071                          * it later.
1072                          *
1073                          * NEEDSWORK: If parent data needs to be reloaded, this
1074                          * prolongs the time that the current thread spends in
1075                          * the mutex. A mitigating factor is that parent data
1076                          * needs to be reloaded only if the delta base cache
1077                          * limit is exceeded, so in the typical case, this does
1078                          * not happen.
1079                          */
1080                         get_base_data(parent);
1081                         parent->retain_data++;
1082                 }
1083                 work_unlock();
1084
1085                 if (parent) {
1086                         child = resolve_delta(child_obj, parent);
1087                         if (!child->children_remaining)
1088                                 FREE_AND_NULL(child->data);
1089                 } else {
1090                         child = make_base(child_obj, NULL);
1091                         if (child->children_remaining) {
1092                                 /*
1093                                  * Since this child has its own delta children,
1094                                  * we will need this data in the future.
1095                                  * Inflate now so that future iterations will
1096                                  * have access to this object's data while
1097                                  * outside the work mutex.
1098                                  */
1099                                 child->data = get_data_from_pack(child_obj);
1100                                 child->size = child_obj->size;
1101                         }
1102                 }
1103
1104                 work_lock();
1105                 if (parent)
1106                         parent->retain_data--;
1107                 if (child->data) {
1108                         /*
1109                          * This child has its own children, so add it to
1110                          * work_head.
1111                          */
1112                         list_add(&child->list, &work_head);
1113                         base_cache_used += child->size;
1114                         prune_base_data(NULL);
1115                         free_base_data(child);
1116                 } else {
1117                         /*
1118                          * This child does not have its own children. It may be
1119                          * the last descendant of its ancestors; free those
1120                          * that we can.
1121                          */
1122                         struct base_data *p = parent;
1123
1124                         while (p) {
1125                                 struct base_data *next_p;
1126
1127                                 p->children_remaining--;
1128                                 if (p->children_remaining)
1129                                         break;
1130
1131                                 next_p = p->base;
1132                                 free_base_data(p);
1133                                 list_del(&p->list);
1134                                 free(p);
1135
1136                                 p = next_p;
1137                         }
1138                         FREE_AND_NULL(child);
1139                 }
1140                 work_unlock();
1141         }
1142         return NULL;
1143 }
1144
1145 /*
1146  * First pass:
1147  * - find locations of all objects;
1148  * - calculate SHA1 of all non-delta objects;
1149  * - remember base (SHA1 or offset) for all deltas.
1150  */
1151 static void parse_pack_objects(unsigned char *hash)
1152 {
1153         int i, nr_delays = 0;
1154         struct ofs_delta_entry *ofs_delta = ofs_deltas;
1155         struct object_id ref_delta_oid;
1156         struct stat st;
1157
1158         if (verbose)
1159                 progress = start_progress(
1160                                 progress_title ? progress_title :
1161                                 from_stdin ? _("Receiving objects") : _("Indexing objects"),
1162                                 nr_objects);
1163         for (i = 0; i < nr_objects; i++) {
1164                 struct object_entry *obj = &objects[i];
1165                 void *data = unpack_raw_entry(obj, &ofs_delta->offset,
1166                                               &ref_delta_oid,
1167                                               &obj->idx.oid);
1168                 obj->real_type = obj->type;
1169                 if (obj->type == OBJ_OFS_DELTA) {
1170                         nr_ofs_deltas++;
1171                         ofs_delta->obj_no = i;
1172                         ofs_delta++;
1173                 } else if (obj->type == OBJ_REF_DELTA) {
1174                         ALLOC_GROW(ref_deltas, nr_ref_deltas + 1, ref_deltas_alloc);
1175                         oidcpy(&ref_deltas[nr_ref_deltas].oid, &ref_delta_oid);
1176                         ref_deltas[nr_ref_deltas].obj_no = i;
1177                         nr_ref_deltas++;
1178                 } else if (!data) {
1179                         /* large blobs, check later */
1180                         obj->real_type = OBJ_BAD;
1181                         nr_delays++;
1182                 } else
1183                         sha1_object(data, NULL, obj->size, obj->type,
1184                                     &obj->idx.oid);
1185                 free(data);
1186                 display_progress(progress, i+1);
1187         }
1188         objects[i].idx.offset = consumed_bytes;
1189         stop_progress(&progress);
1190
1191         /* Check pack integrity */
1192         flush();
1193         the_hash_algo->final_fn(hash, &input_ctx);
1194         if (!hasheq(fill(the_hash_algo->rawsz), hash))
1195                 die(_("pack is corrupted (SHA1 mismatch)"));
1196         use(the_hash_algo->rawsz);
1197
1198         /* If input_fd is a file, we should have reached its end now. */
1199         if (fstat(input_fd, &st))
1200                 die_errno(_("cannot fstat packfile"));
1201         if (S_ISREG(st.st_mode) &&
1202                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
1203                 die(_("pack has junk at the end"));
1204
1205         for (i = 0; i < nr_objects; i++) {
1206                 struct object_entry *obj = &objects[i];
1207                 if (obj->real_type != OBJ_BAD)
1208                         continue;
1209                 obj->real_type = obj->type;
1210                 sha1_object(NULL, obj, obj->size, obj->type,
1211                             &obj->idx.oid);
1212                 nr_delays--;
1213         }
1214         if (nr_delays)
1215                 die(_("confusion beyond insanity in parse_pack_objects()"));
1216 }
1217
1218 /*
1219  * Second pass:
1220  * - for all non-delta objects, look if it is used as a base for
1221  *   deltas;
1222  * - if used as a base, uncompress the object and apply all deltas,
1223  *   recursively checking if the resulting object is used as a base
1224  *   for some more deltas.
1225  */
1226 static void resolve_deltas(void)
1227 {
1228         int i;
1229
1230         if (!nr_ofs_deltas && !nr_ref_deltas)
1231                 return;
1232
1233         /* Sort deltas by base SHA1/offset for fast searching */
1234         QSORT(ofs_deltas, nr_ofs_deltas, compare_ofs_delta_entry);
1235         QSORT(ref_deltas, nr_ref_deltas, compare_ref_delta_entry);
1236
1237         if (verbose || show_resolving_progress)
1238                 progress = start_progress(_("Resolving deltas"),
1239                                           nr_ref_deltas + nr_ofs_deltas);
1240
1241         nr_dispatched = 0;
1242         base_cache_limit = delta_base_cache_limit * nr_threads;
1243         if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) {
1244                 init_thread();
1245                 for (i = 0; i < nr_threads; i++) {
1246                         int ret = pthread_create(&thread_data[i].thread, NULL,
1247                                                  threaded_second_pass, thread_data + i);
1248                         if (ret)
1249                                 die(_("unable to create thread: %s"),
1250                                     strerror(ret));
1251                 }
1252                 for (i = 0; i < nr_threads; i++)
1253                         pthread_join(thread_data[i].thread, NULL);
1254                 cleanup_thread();
1255                 return;
1256         }
1257         threaded_second_pass(&nothread_data);
1258 }
1259
1260 /*
1261  * Third pass:
1262  * - append objects to convert thin pack to full pack if required
1263  * - write the final pack hash
1264  */
1265 static void fix_unresolved_deltas(struct hashfile *f);
1266 static void conclude_pack(int fix_thin_pack, const char *curr_pack, unsigned char *pack_hash)
1267 {
1268         if (nr_ref_deltas + nr_ofs_deltas == nr_resolved_deltas) {
1269                 stop_progress(&progress);
1270                 /* Flush remaining pack final hash. */
1271                 flush();
1272                 return;
1273         }
1274
1275         if (fix_thin_pack) {
1276                 struct hashfile *f;
1277                 unsigned char read_hash[GIT_MAX_RAWSZ], tail_hash[GIT_MAX_RAWSZ];
1278                 struct strbuf msg = STRBUF_INIT;
1279                 int nr_unresolved = nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas;
1280                 int nr_objects_initial = nr_objects;
1281                 if (nr_unresolved <= 0)
1282                         die(_("confusion beyond insanity"));
1283                 REALLOC_ARRAY(objects, nr_objects + nr_unresolved + 1);
1284                 memset(objects + nr_objects + 1, 0,
1285                        nr_unresolved * sizeof(*objects));
1286                 f = hashfd(output_fd, curr_pack);
1287                 fix_unresolved_deltas(f);
1288                 strbuf_addf(&msg, Q_("completed with %d local object",
1289                                      "completed with %d local objects",
1290                                      nr_objects - nr_objects_initial),
1291                             nr_objects - nr_objects_initial);
1292                 stop_progress_msg(&progress, msg.buf);
1293                 strbuf_release(&msg);
1294                 finalize_hashfile(f, tail_hash, FSYNC_COMPONENT_PACK, 0);
1295                 hashcpy(read_hash, pack_hash);
1296                 fixup_pack_header_footer(output_fd, pack_hash,
1297                                          curr_pack, nr_objects,
1298                                          read_hash, consumed_bytes-the_hash_algo->rawsz);
1299                 if (!hasheq(read_hash, tail_hash))
1300                         die(_("Unexpected tail checksum for %s "
1301                               "(disk corruption?)"), curr_pack);
1302         }
1303         if (nr_ofs_deltas + nr_ref_deltas != nr_resolved_deltas)
1304                 die(Q_("pack has %d unresolved delta",
1305                        "pack has %d unresolved deltas",
1306                        nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas),
1307                     nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas);
1308 }
1309
1310 static int write_compressed(struct hashfile *f, void *in, unsigned int size)
1311 {
1312         git_zstream stream;
1313         int status;
1314         unsigned char outbuf[4096];
1315
1316         git_deflate_init(&stream, zlib_compression_level);
1317         stream.next_in = in;
1318         stream.avail_in = size;
1319
1320         do {
1321                 stream.next_out = outbuf;
1322                 stream.avail_out = sizeof(outbuf);
1323                 status = git_deflate(&stream, Z_FINISH);
1324                 hashwrite(f, outbuf, sizeof(outbuf) - stream.avail_out);
1325         } while (status == Z_OK);
1326
1327         if (status != Z_STREAM_END)
1328                 die(_("unable to deflate appended object (%d)"), status);
1329         size = stream.total_out;
1330         git_deflate_end(&stream);
1331         return size;
1332 }
1333
1334 static struct object_entry *append_obj_to_pack(struct hashfile *f,
1335                                const unsigned char *sha1, void *buf,
1336                                unsigned long size, enum object_type type)
1337 {
1338         struct object_entry *obj = &objects[nr_objects++];
1339         unsigned char header[10];
1340         unsigned long s = size;
1341         int n = 0;
1342         unsigned char c = (type << 4) | (s & 15);
1343         s >>= 4;
1344         while (s) {
1345                 header[n++] = c | 0x80;
1346                 c = s & 0x7f;
1347                 s >>= 7;
1348         }
1349         header[n++] = c;
1350         crc32_begin(f);
1351         hashwrite(f, header, n);
1352         obj[0].size = size;
1353         obj[0].hdr_size = n;
1354         obj[0].type = type;
1355         obj[0].real_type = type;
1356         obj[1].idx.offset = obj[0].idx.offset + n;
1357         obj[1].idx.offset += write_compressed(f, buf, size);
1358         obj[0].idx.crc32 = crc32_end(f);
1359         hashflush(f);
1360         oidread(&obj->idx.oid, sha1);
1361         return obj;
1362 }
1363
1364 static int delta_pos_compare(const void *_a, const void *_b)
1365 {
1366         struct ref_delta_entry *a = *(struct ref_delta_entry **)_a;
1367         struct ref_delta_entry *b = *(struct ref_delta_entry **)_b;
1368         return a->obj_no - b->obj_no;
1369 }
1370
1371 static void fix_unresolved_deltas(struct hashfile *f)
1372 {
1373         struct ref_delta_entry **sorted_by_pos;
1374         int i;
1375
1376         /*
1377          * Since many unresolved deltas may well be themselves base objects
1378          * for more unresolved deltas, we really want to include the
1379          * smallest number of base objects that would cover as much delta
1380          * as possible by picking the
1381          * trunc deltas first, allowing for other deltas to resolve without
1382          * additional base objects.  Since most base objects are to be found
1383          * before deltas depending on them, a good heuristic is to start
1384          * resolving deltas in the same order as their position in the pack.
1385          */
1386         ALLOC_ARRAY(sorted_by_pos, nr_ref_deltas);
1387         for (i = 0; i < nr_ref_deltas; i++)
1388                 sorted_by_pos[i] = &ref_deltas[i];
1389         QSORT(sorted_by_pos, nr_ref_deltas, delta_pos_compare);
1390
1391         if (has_promisor_remote()) {
1392                 /*
1393                  * Prefetch the delta bases.
1394                  */
1395                 struct oid_array to_fetch = OID_ARRAY_INIT;
1396                 for (i = 0; i < nr_ref_deltas; i++) {
1397                         struct ref_delta_entry *d = sorted_by_pos[i];
1398                         if (!oid_object_info_extended(the_repository, &d->oid,
1399                                                       NULL,
1400                                                       OBJECT_INFO_FOR_PREFETCH))
1401                                 continue;
1402                         oid_array_append(&to_fetch, &d->oid);
1403                 }
1404                 promisor_remote_get_direct(the_repository,
1405                                            to_fetch.oid, to_fetch.nr);
1406                 oid_array_clear(&to_fetch);
1407         }
1408
1409         for (i = 0; i < nr_ref_deltas; i++) {
1410                 struct ref_delta_entry *d = sorted_by_pos[i];
1411                 enum object_type type;
1412                 void *data;
1413                 unsigned long size;
1414
1415                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
1416                         continue;
1417                 data = read_object_file(&d->oid, &type, &size);
1418                 if (!data)
1419                         continue;
1420
1421                 if (check_object_signature(the_repository, &d->oid, data, size,
1422                                            type) < 0)
1423                         die(_("local object %s is corrupt"), oid_to_hex(&d->oid));
1424
1425                 /*
1426                  * Add this as an object to the objects array and call
1427                  * threaded_second_pass() (which will pick up the added
1428                  * object).
1429                  */
1430                 append_obj_to_pack(f, d->oid.hash, data, size, type);
1431                 free(data);
1432                 threaded_second_pass(NULL);
1433
1434                 display_progress(progress, nr_resolved_deltas);
1435         }
1436         free(sorted_by_pos);
1437 }
1438
1439 static const char *derive_filename(const char *pack_name, const char *strip,
1440                                    const char *suffix, struct strbuf *buf)
1441 {
1442         size_t len;
1443         if (!strip_suffix(pack_name, strip, &len) || !len ||
1444             pack_name[len - 1] != '.')
1445                 die(_("packfile name '%s' does not end with '.%s'"),
1446                     pack_name, strip);
1447         strbuf_add(buf, pack_name, len);
1448         strbuf_addstr(buf, suffix);
1449         return buf->buf;
1450 }
1451
1452 static void write_special_file(const char *suffix, const char *msg,
1453                                const char *pack_name, const unsigned char *hash,
1454                                const char **report)
1455 {
1456         struct strbuf name_buf = STRBUF_INIT;
1457         const char *filename;
1458         int fd;
1459         int msg_len = strlen(msg);
1460
1461         if (pack_name)
1462                 filename = derive_filename(pack_name, "pack", suffix, &name_buf);
1463         else
1464                 filename = odb_pack_name(&name_buf, hash, suffix);
1465
1466         fd = odb_pack_keep(filename);
1467         if (fd < 0) {
1468                 if (errno != EEXIST)
1469                         die_errno(_("cannot write %s file '%s'"),
1470                                   suffix, filename);
1471         } else {
1472                 if (msg_len > 0) {
1473                         write_or_die(fd, msg, msg_len);
1474                         write_or_die(fd, "\n", 1);
1475                 }
1476                 if (close(fd) != 0)
1477                         die_errno(_("cannot close written %s file '%s'"),
1478                                   suffix, filename);
1479                 if (report)
1480                         *report = suffix;
1481         }
1482         strbuf_release(&name_buf);
1483 }
1484
1485 static void rename_tmp_packfile(const char **final_name,
1486                                 const char *curr_name,
1487                                 struct strbuf *name, unsigned char *hash,
1488                                 const char *ext, int make_read_only_if_same)
1489 {
1490         if (*final_name != curr_name) {
1491                 if (!*final_name)
1492                         *final_name = odb_pack_name(name, hash, ext);
1493                 if (finalize_object_file(curr_name, *final_name))
1494                         die(_("unable to rename temporary '*.%s' file to '%s'"),
1495                             ext, *final_name);
1496         } else if (make_read_only_if_same) {
1497                 chmod(*final_name, 0444);
1498         }
1499 }
1500
1501 static void final(const char *final_pack_name, const char *curr_pack_name,
1502                   const char *final_index_name, const char *curr_index_name,
1503                   const char *final_rev_index_name, const char *curr_rev_index_name,
1504                   const char *keep_msg, const char *promisor_msg,
1505                   unsigned char *hash)
1506 {
1507         const char *report = "pack";
1508         struct strbuf pack_name = STRBUF_INIT;
1509         struct strbuf index_name = STRBUF_INIT;
1510         struct strbuf rev_index_name = STRBUF_INIT;
1511         int err;
1512
1513         if (!from_stdin) {
1514                 close(input_fd);
1515         } else {
1516                 fsync_component_or_die(FSYNC_COMPONENT_PACK, output_fd, curr_pack_name);
1517                 err = close(output_fd);
1518                 if (err)
1519                         die_errno(_("error while closing pack file"));
1520         }
1521
1522         if (keep_msg)
1523                 write_special_file("keep", keep_msg, final_pack_name, hash,
1524                                    &report);
1525         if (promisor_msg)
1526                 write_special_file("promisor", promisor_msg, final_pack_name,
1527                                    hash, NULL);
1528
1529         rename_tmp_packfile(&final_pack_name, curr_pack_name, &pack_name,
1530                             hash, "pack", from_stdin);
1531         if (curr_rev_index_name)
1532                 rename_tmp_packfile(&final_rev_index_name, curr_rev_index_name,
1533                                     &rev_index_name, hash, "rev", 1);
1534         rename_tmp_packfile(&final_index_name, curr_index_name, &index_name,
1535                             hash, "idx", 1);
1536
1537         if (do_fsck_object) {
1538                 struct packed_git *p;
1539                 p = add_packed_git(final_index_name, strlen(final_index_name), 0);
1540                 if (p)
1541                         install_packed_git(the_repository, p);
1542         }
1543
1544         if (!from_stdin) {
1545                 printf("%s\n", hash_to_hex(hash));
1546         } else {
1547                 struct strbuf buf = STRBUF_INIT;
1548
1549                 strbuf_addf(&buf, "%s\t%s\n", report, hash_to_hex(hash));
1550                 write_or_die(1, buf.buf, buf.len);
1551                 strbuf_release(&buf);
1552
1553                 /*
1554                  * Let's just mimic git-unpack-objects here and write
1555                  * the last part of the input buffer to stdout.
1556                  */
1557                 while (input_len) {
1558                         err = xwrite(1, input_buffer + input_offset, input_len);
1559                         if (err <= 0)
1560                                 break;
1561                         input_len -= err;
1562                         input_offset += err;
1563                 }
1564         }
1565
1566         strbuf_release(&rev_index_name);
1567         strbuf_release(&index_name);
1568         strbuf_release(&pack_name);
1569 }
1570
1571 static int git_index_pack_config(const char *k, const char *v, void *cb)
1572 {
1573         struct pack_idx_option *opts = cb;
1574
1575         if (!strcmp(k, "pack.indexversion")) {
1576                 opts->version = git_config_int(k, v);
1577                 if (opts->version > 2)
1578                         die(_("bad pack.indexVersion=%"PRIu32), opts->version);
1579                 return 0;
1580         }
1581         if (!strcmp(k, "pack.threads")) {
1582                 nr_threads = git_config_int(k, v);
1583                 if (nr_threads < 0)
1584                         die(_("invalid number of threads specified (%d)"),
1585                             nr_threads);
1586                 if (!HAVE_THREADS && nr_threads != 1) {
1587                         warning(_("no threads support, ignoring %s"), k);
1588                         nr_threads = 1;
1589                 }
1590                 return 0;
1591         }
1592         if (!strcmp(k, "pack.writereverseindex")) {
1593                 if (git_config_bool(k, v))
1594                         opts->flags |= WRITE_REV;
1595                 else
1596                         opts->flags &= ~WRITE_REV;
1597         }
1598         return git_default_config(k, v, cb);
1599 }
1600
1601 static int cmp_uint32(const void *a_, const void *b_)
1602 {
1603         uint32_t a = *((uint32_t *)a_);
1604         uint32_t b = *((uint32_t *)b_);
1605
1606         return (a < b) ? -1 : (a != b);
1607 }
1608
1609 static void read_v2_anomalous_offsets(struct packed_git *p,
1610                                       struct pack_idx_option *opts)
1611 {
1612         const uint32_t *idx1, *idx2;
1613         uint32_t i;
1614
1615         /* The address of the 4-byte offset table */
1616         idx1 = (((const uint32_t *)((const uint8_t *)p->index_data + p->crc_offset))
1617                 + (size_t)p->num_objects /* CRC32 table */
1618                 );
1619
1620         /* The address of the 8-byte offset table */
1621         idx2 = idx1 + p->num_objects;
1622
1623         for (i = 0; i < p->num_objects; i++) {
1624                 uint32_t off = ntohl(idx1[i]);
1625                 if (!(off & 0x80000000))
1626                         continue;
1627                 off = off & 0x7fffffff;
1628                 check_pack_index_ptr(p, &idx2[off * 2]);
1629                 if (idx2[off * 2])
1630                         continue;
1631                 /*
1632                  * The real offset is ntohl(idx2[off * 2]) in high 4
1633                  * octets, and ntohl(idx2[off * 2 + 1]) in low 4
1634                  * octets.  But idx2[off * 2] is Zero!!!
1635                  */
1636                 ALLOC_GROW(opts->anomaly, opts->anomaly_nr + 1, opts->anomaly_alloc);
1637                 opts->anomaly[opts->anomaly_nr++] = ntohl(idx2[off * 2 + 1]);
1638         }
1639
1640         QSORT(opts->anomaly, opts->anomaly_nr, cmp_uint32);
1641 }
1642
1643 static void read_idx_option(struct pack_idx_option *opts, const char *pack_name)
1644 {
1645         struct packed_git *p = add_packed_git(pack_name, strlen(pack_name), 1);
1646
1647         if (!p)
1648                 die(_("Cannot open existing pack file '%s'"), pack_name);
1649         if (open_pack_index(p))
1650                 die(_("Cannot open existing pack idx file for '%s'"), pack_name);
1651
1652         /* Read the attributes from the existing idx file */
1653         opts->version = p->index_version;
1654
1655         if (opts->version == 2)
1656                 read_v2_anomalous_offsets(p, opts);
1657
1658         /*
1659          * Get rid of the idx file as we do not need it anymore.
1660          * NEEDSWORK: extract this bit from free_pack_by_name() in
1661          * object-file.c, perhaps?  It shouldn't matter very much as we
1662          * know we haven't installed this pack (hence we never have
1663          * read anything from it).
1664          */
1665         close_pack_index(p);
1666         free(p);
1667 }
1668
1669 static void show_pack_info(int stat_only)
1670 {
1671         int i, baseobjects = nr_objects - nr_ref_deltas - nr_ofs_deltas;
1672         unsigned long *chain_histogram = NULL;
1673
1674         if (deepest_delta)
1675                 CALLOC_ARRAY(chain_histogram, deepest_delta);
1676
1677         for (i = 0; i < nr_objects; i++) {
1678                 struct object_entry *obj = &objects[i];
1679
1680                 if (is_delta_type(obj->type))
1681                         chain_histogram[obj_stat[i].delta_depth - 1]++;
1682                 if (stat_only)
1683                         continue;
1684                 printf("%s %-6s %"PRIuMAX" %"PRIuMAX" %"PRIuMAX,
1685                        oid_to_hex(&obj->idx.oid),
1686                        type_name(obj->real_type), (uintmax_t)obj->size,
1687                        (uintmax_t)(obj[1].idx.offset - obj->idx.offset),
1688                        (uintmax_t)obj->idx.offset);
1689                 if (is_delta_type(obj->type)) {
1690                         struct object_entry *bobj = &objects[obj_stat[i].base_object_no];
1691                         printf(" %u %s", obj_stat[i].delta_depth,
1692                                oid_to_hex(&bobj->idx.oid));
1693                 }
1694                 putchar('\n');
1695         }
1696
1697         if (baseobjects)
1698                 printf_ln(Q_("non delta: %d object",
1699                              "non delta: %d objects",
1700                              baseobjects),
1701                           baseobjects);
1702         for (i = 0; i < deepest_delta; i++) {
1703                 if (!chain_histogram[i])
1704                         continue;
1705                 printf_ln(Q_("chain length = %d: %lu object",
1706                              "chain length = %d: %lu objects",
1707                              chain_histogram[i]),
1708                           i + 1,
1709                           chain_histogram[i]);
1710         }
1711         free(chain_histogram);
1712 }
1713
1714 int cmd_index_pack(int argc, const char **argv, const char *prefix)
1715 {
1716         int i, fix_thin_pack = 0, verify = 0, stat_only = 0, rev_index;
1717         const char *curr_index;
1718         const char *curr_rev_index = NULL;
1719         const char *index_name = NULL, *pack_name = NULL, *rev_index_name = NULL;
1720         const char *keep_msg = NULL;
1721         const char *promisor_msg = NULL;
1722         struct strbuf index_name_buf = STRBUF_INIT;
1723         struct strbuf rev_index_name_buf = STRBUF_INIT;
1724         struct pack_idx_entry **idx_objects;
1725         struct pack_idx_option opts;
1726         unsigned char pack_hash[GIT_MAX_RAWSZ];
1727         unsigned foreign_nr = 1;        /* zero is a "good" value, assume bad */
1728         int report_end_of_input = 0;
1729         int hash_algo = 0;
1730
1731         /*
1732          * index-pack never needs to fetch missing objects except when
1733          * REF_DELTA bases are missing (which are explicitly handled). It only
1734          * accesses the repo to do hash collision checks and to check which
1735          * REF_DELTA bases need to be fetched.
1736          */
1737         fetch_if_missing = 0;
1738
1739         if (argc == 2 && !strcmp(argv[1], "-h"))
1740                 usage(index_pack_usage);
1741
1742         read_replace_refs = 0;
1743         fsck_options.walk = mark_link;
1744
1745         reset_pack_idx_option(&opts);
1746         git_config(git_index_pack_config, &opts);
1747         if (prefix && chdir(prefix))
1748                 die(_("Cannot come back to cwd"));
1749
1750         if (git_env_bool(GIT_TEST_WRITE_REV_INDEX, 0))
1751                 rev_index = 1;
1752         else
1753                 rev_index = !!(opts.flags & (WRITE_REV_VERIFY | WRITE_REV));
1754
1755         for (i = 1; i < argc; i++) {
1756                 const char *arg = argv[i];
1757
1758                 if (*arg == '-') {
1759                         if (!strcmp(arg, "--stdin")) {
1760                                 from_stdin = 1;
1761                         } else if (!strcmp(arg, "--fix-thin")) {
1762                                 fix_thin_pack = 1;
1763                         } else if (skip_to_optional_arg(arg, "--strict", &arg)) {
1764                                 strict = 1;
1765                                 do_fsck_object = 1;
1766                                 fsck_set_msg_types(&fsck_options, arg);
1767                         } else if (!strcmp(arg, "--check-self-contained-and-connected")) {
1768                                 strict = 1;
1769                                 check_self_contained_and_connected = 1;
1770                         } else if (!strcmp(arg, "--fsck-objects")) {
1771                                 do_fsck_object = 1;
1772                         } else if (!strcmp(arg, "--verify")) {
1773                                 verify = 1;
1774                         } else if (!strcmp(arg, "--verify-stat")) {
1775                                 verify = 1;
1776                                 show_stat = 1;
1777                         } else if (!strcmp(arg, "--verify-stat-only")) {
1778                                 verify = 1;
1779                                 show_stat = 1;
1780                                 stat_only = 1;
1781                         } else if (skip_to_optional_arg(arg, "--keep", &keep_msg)) {
1782                                 ; /* nothing to do */
1783                         } else if (skip_to_optional_arg(arg, "--promisor", &promisor_msg)) {
1784                                 ; /* already parsed */
1785                         } else if (starts_with(arg, "--threads=")) {
1786                                 char *end;
1787                                 nr_threads = strtoul(arg+10, &end, 0);
1788                                 if (!arg[10] || *end || nr_threads < 0)
1789                                         usage(index_pack_usage);
1790                                 if (!HAVE_THREADS && nr_threads != 1) {
1791                                         warning(_("no threads support, ignoring %s"), arg);
1792                                         nr_threads = 1;
1793                                 }
1794                         } else if (starts_with(arg, "--pack_header=")) {
1795                                 struct pack_header *hdr;
1796                                 char *c;
1797
1798                                 hdr = (struct pack_header *)input_buffer;
1799                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
1800                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
1801                                 if (*c != ',')
1802                                         die(_("bad %s"), arg);
1803                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
1804                                 if (*c)
1805                                         die(_("bad %s"), arg);
1806                                 input_len = sizeof(*hdr);
1807                         } else if (!strcmp(arg, "-v")) {
1808                                 verbose = 1;
1809                         } else if (!strcmp(arg, "--progress-title")) {
1810                                 if (progress_title || (i+1) >= argc)
1811                                         usage(index_pack_usage);
1812                                 progress_title = argv[++i];
1813                         } else if (!strcmp(arg, "--show-resolving-progress")) {
1814                                 show_resolving_progress = 1;
1815                         } else if (!strcmp(arg, "--report-end-of-input")) {
1816                                 report_end_of_input = 1;
1817                         } else if (!strcmp(arg, "-o")) {
1818                                 if (index_name || (i+1) >= argc)
1819                                         usage(index_pack_usage);
1820                                 index_name = argv[++i];
1821                         } else if (starts_with(arg, "--index-version=")) {
1822                                 char *c;
1823                                 opts.version = strtoul(arg + 16, &c, 10);
1824                                 if (opts.version > 2)
1825                                         die(_("bad %s"), arg);
1826                                 if (*c == ',')
1827                                         opts.off32_limit = strtoul(c+1, &c, 0);
1828                                 if (*c || opts.off32_limit & 0x80000000)
1829                                         die(_("bad %s"), arg);
1830                         } else if (skip_prefix(arg, "--max-input-size=", &arg)) {
1831                                 max_input_size = strtoumax(arg, NULL, 10);
1832                         } else if (skip_prefix(arg, "--object-format=", &arg)) {
1833                                 hash_algo = hash_algo_by_name(arg);
1834                                 if (hash_algo == GIT_HASH_UNKNOWN)
1835                                         die(_("unknown hash algorithm '%s'"), arg);
1836                                 repo_set_hash_algo(the_repository, hash_algo);
1837                         } else if (!strcmp(arg, "--rev-index")) {
1838                                 rev_index = 1;
1839                         } else if (!strcmp(arg, "--no-rev-index")) {
1840                                 rev_index = 0;
1841                         } else
1842                                 usage(index_pack_usage);
1843                         continue;
1844                 }
1845
1846                 if (pack_name)
1847                         usage(index_pack_usage);
1848                 pack_name = arg;
1849         }
1850
1851         if (!pack_name && !from_stdin)
1852                 usage(index_pack_usage);
1853         if (fix_thin_pack && !from_stdin)
1854                 die(_("the option '%s' requires '%s'"), "--fix-thin", "--stdin");
1855         if (from_stdin && !startup_info->have_repository)
1856                 die(_("--stdin requires a git repository"));
1857         if (from_stdin && hash_algo)
1858                 die(_("options '%s' and '%s' cannot be used together"), "--object-format", "--stdin");
1859         if (!index_name && pack_name)
1860                 index_name = derive_filename(pack_name, "pack", "idx", &index_name_buf);
1861
1862         opts.flags &= ~(WRITE_REV | WRITE_REV_VERIFY);
1863         if (rev_index) {
1864                 opts.flags |= verify ? WRITE_REV_VERIFY : WRITE_REV;
1865                 if (index_name)
1866                         rev_index_name = derive_filename(index_name,
1867                                                          "idx", "rev",
1868                                                          &rev_index_name_buf);
1869         }
1870
1871         if (verify) {
1872                 if (!index_name)
1873                         die(_("--verify with no packfile name given"));
1874                 read_idx_option(&opts, index_name);
1875                 opts.flags |= WRITE_IDX_VERIFY | WRITE_IDX_STRICT;
1876         }
1877         if (strict)
1878                 opts.flags |= WRITE_IDX_STRICT;
1879
1880         if (HAVE_THREADS && !nr_threads) {
1881                 nr_threads = online_cpus();
1882                 /*
1883                  * Experiments show that going above 20 threads doesn't help,
1884                  * no matter how many cores you have. Below that, we tend to
1885                  * max at half the number of online_cpus(), presumably because
1886                  * half of those are hyperthreads rather than full cores. We'll
1887                  * never reduce the level below "3", though, to match a
1888                  * historical value that nobody complained about.
1889                  */
1890                 if (nr_threads < 4)
1891                         ; /* too few cores to consider capping */
1892                 else if (nr_threads < 6)
1893                         nr_threads = 3; /* historic cap */
1894                 else if (nr_threads < 40)
1895                         nr_threads /= 2;
1896                 else
1897                         nr_threads = 20; /* hard cap */
1898         }
1899
1900         curr_pack = open_pack_file(pack_name);
1901         parse_pack_header();
1902         CALLOC_ARRAY(objects, st_add(nr_objects, 1));
1903         if (show_stat)
1904                 CALLOC_ARRAY(obj_stat, st_add(nr_objects, 1));
1905         CALLOC_ARRAY(ofs_deltas, nr_objects);
1906         parse_pack_objects(pack_hash);
1907         if (report_end_of_input)
1908                 write_in_full(2, "\0", 1);
1909         resolve_deltas();
1910         conclude_pack(fix_thin_pack, curr_pack, pack_hash);
1911         free(ofs_deltas);
1912         free(ref_deltas);
1913         if (strict)
1914                 foreign_nr = check_objects();
1915
1916         if (show_stat)
1917                 show_pack_info(stat_only);
1918
1919         ALLOC_ARRAY(idx_objects, nr_objects);
1920         for (i = 0; i < nr_objects; i++)
1921                 idx_objects[i] = &objects[i].idx;
1922         curr_index = write_idx_file(index_name, idx_objects, nr_objects, &opts, pack_hash);
1923         if (rev_index)
1924                 curr_rev_index = write_rev_file(rev_index_name, idx_objects,
1925                                                 nr_objects, pack_hash,
1926                                                 opts.flags);
1927         free(idx_objects);
1928
1929         if (!verify)
1930                 final(pack_name, curr_pack,
1931                       index_name, curr_index,
1932                       rev_index_name, curr_rev_index,
1933                       keep_msg, promisor_msg,
1934                       pack_hash);
1935         else
1936                 close(input_fd);
1937
1938         if (do_fsck_object && fsck_finish(&fsck_options))
1939                 die(_("fsck error in pack objects"));
1940
1941         free(opts.anomaly);
1942         free(objects);
1943         strbuf_release(&index_name_buf);
1944         strbuf_release(&rev_index_name_buf);
1945         if (!pack_name)
1946                 free((void *) curr_pack);
1947         if (!index_name)
1948                 free((void *) curr_index);
1949         if (!rev_index_name)
1950                 free((void *) curr_rev_index);
1951
1952         /*
1953          * Let the caller know this pack is not self contained
1954          */
1955         if (check_self_contained_and_connected && foreign_nr)
1956                 return 1;
1957
1958         return 0;
1959 }