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                 die(_("pack exceeds maximum allowed size"));
 328 }
 329
 330 static const char *open_pack_file(const char *pack_name)
 331 {
 332         if (from_stdin) {
 333                 input_fd = 0;
 334                 if (!pack_name) {
 335                         struct strbuf tmp_file = STRBUF_INIT;
 336                         output_fd = odb_mkstemp(&tmp_file,
 337                                                 "pack/tmp_pack_XXXXXX");
 338                         pack_name = strbuf_detach(&tmp_file, NULL);
 339                 } else {
 340                         output_fd = xopen(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 341                 }
 342                 nothread_data.pack_fd = output_fd;
 343         } else {
 344                 input_fd = xopen(pack_name, O_RDONLY);
 345                 output_fd = -1;
 346                 nothread_data.pack_fd = input_fd;
 347         }
 348         the_hash_algo->init_fn(&input_ctx);
 349         return pack_name;
 350 }
 351
 352 static void parse_pack_header(void)
 353 {
 354         struct pack_header *hdr = fill(sizeof(struct pack_header));
 355
 356         /* Header consistency check */
 357         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 358                 die(_("pack signature mismatch"));
 359         if (!pack_version_ok(hdr->hdr_version))
 360                 die(_("pack version %"PRIu32" unsupported"),
 361                         ntohl(hdr->hdr_version));
 362
 363         nr_objects = ntohl(hdr->hdr_entries);
 364         use(sizeof(struct pack_header));
 365 }
 366
 367 __attribute__((format (printf, 2, 3)))
 368 static NORETURN void bad_object(off_t offset, const char *format, ...)
 369 {
 370         va_list params;
 371         char buf[1024];
 372
 373         va_start(params, format);
 374         vsnprintf(buf, sizeof(buf), format, params);
 375         va_end(params);
 376         die(_("pack has bad object at offset %"PRIuMAX": %s"),
 377             (uintmax_t)offset, buf);
 378 }
 379
 380 static inline struct thread_local *get_thread_data(void)
 381 {
 382         if (HAVE_THREADS) {
 383                 if (threads_active)
 384                         return pthread_getspecific(key);
 385                 assert(!threads_active &&
 386                        "This should only be reached when all threads are gone");
 387         }
 388         return &nothread_data;
 389 }
 390
 391 static void set_thread_data(struct thread_local *data)
 392 {
 393         if (threads_active)
 394                 pthread_setspecific(key, data);
 395 }
 396
 397 static void free_base_data(struct base_data *c)
 398 {
 399         if (c->data) {
 400                 FREE_AND_NULL(c->data);
 401                 base_cache_used -= c->size;
 402         }
 403 }
 404
 405 static void prune_base_data(struct base_data *retain)
 406 {
 407         struct list_head *pos;
 408
 409         if (base_cache_used <= base_cache_limit)
 410                 return;
 411
 412         list_for_each_prev(pos, &done_head) {
 413                 struct base_data *b = list_entry(pos, struct base_data, list);
 414                 if (b->retain_data || b == retain)
 415                         continue;
 416                 if (b->data) {
 417                         free_base_data(b);
 418                         if (base_cache_used <= base_cache_limit)
 419                                 return;
 420                 }
 421         }
 422
 423         list_for_each_prev(pos, &work_head) {
 424                 struct base_data *b = list_entry(pos, struct base_data, list);
 425                 if (b->retain_data || b == retain)
 426                         continue;
 427                 if (b->data) {
 428                         free_base_data(b);
 429                         if (base_cache_used <= base_cache_limit)
 430                                 return;
 431                 }
 432         }
 433 }
 434
 435 static int is_delta_type(enum object_type type)
 436 {
 437         return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
 438 }
 439
 440 static void *unpack_entry_data(off_t offset, unsigned long size,
 441                                enum object_type type, struct object_id *oid)
 442 {
 443         static char fixed_buf[8192];
 444         int status;
 445         git_zstream stream;
 446         void *buf;
 447         git_hash_ctx c;
 448         char hdr[32];
 449         int hdrlen;
 450
 451         if (!is_delta_type(type)) {
 452                 hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX,
 453                                    type_name(type),(uintmax_t)size) + 1;
 454                 the_hash_algo->init_fn(&c);
 455                 the_hash_algo->update_fn(&c, hdr, hdrlen);
 456         } else
 457                 oid = NULL;
 458         if (type == OBJ_BLOB && size > big_file_threshold)
 459                 buf = fixed_buf;
 460         else
 461                 buf = xmallocz(size);
 462
 463         memset(&stream, 0, sizeof(stream));
 464         git_inflate_init(&stream);
 465         stream.next_out = buf;
 466         stream.avail_out = buf == fixed_buf ? sizeof(fixed_buf) : size;
 467
 468         do {
 469                 unsigned char *last_out = stream.next_out;
 470                 stream.next_in = fill(1);
 471                 stream.avail_in = input_len;
 472                 status = git_inflate(&stream, 0);
 473                 use(input_len - stream.avail_in);
 474                 if (oid)
 475                         the_hash_algo->update_fn(&c, last_out, stream.next_out - last_out);
 476                 if (buf == fixed_buf) {
 477                         stream.next_out = buf;
 478                         stream.avail_out = sizeof(fixed_buf);
 479                 }
 480         } while (status == Z_OK);
 481         if (stream.total_out != size || status != Z_STREAM_END)
 482                 bad_object(offset, _("inflate returned %d"), status);
 483         git_inflate_end(&stream);
 484         if (oid)
 485                 the_hash_algo->final_oid_fn(oid, &c);
 486         return buf == fixed_buf ? NULL : buf;
 487 }
 488
 489 static void *unpack_raw_entry(struct object_entry *obj,
 490                               off_t *ofs_offset,
 491                               struct object_id *ref_oid,
 492                               struct object_id *oid)
 493 {
 494         unsigned char *p;
 495         unsigned long size, c;
 496         off_t base_offset;
 497         unsigned shift;
 498         void *data;
 499
 500         obj->idx.offset = consumed_bytes;
 501         input_crc32 = crc32(0, NULL, 0);
 502
 503         p = fill(1);
 504         c = *p;
 505         use(1);
 506         obj->type = (c >> 4) & 7;
 507         size = (c & 15);
 508         shift = 4;
 509         while (c & 0x80) {
 510                 p = fill(1);
 511                 c = *p;
 512                 use(1);
 513                 size += (c & 0x7f) << shift;
 514                 shift += 7;
 515         }
 516         obj->size = size;
 517
 518         switch (obj->type) {
 519         case OBJ_REF_DELTA:
 520                 oidread(ref_oid, fill(the_hash_algo->rawsz));
 521                 use(the_hash_algo->rawsz);
 522                 break;
 523         case OBJ_OFS_DELTA:
 524                 p = fill(1);
 525                 c = *p;
 526                 use(1);
 527                 base_offset = c & 127;
 528                 while (c & 128) {
 529                         base_offset += 1;
 530                         if (!base_offset || MSB(base_offset, 7))
 531                                 bad_object(obj->idx.offset, _("offset value overflow for delta base object"));
 532                         p = fill(1);
 533                         c = *p;
 534                         use(1);
 535                         base_offset = (base_offset << 7) + (c & 127);
 536                 }
 537                 *ofs_offset = obj->idx.offset - base_offset;
 538                 if (*ofs_offset <= 0 || *ofs_offset >= obj->idx.offset)
 539                         bad_object(obj->idx.offset, _("delta base offset is out of bound"));
 540                 break;
 541         case OBJ_COMMIT:
 542         case OBJ_TREE:
 543         case OBJ_BLOB:
 544         case OBJ_TAG:
 545                 break;
 546         default:
 547                 bad_object(obj->idx.offset, _("unknown object type %d"), obj->type);
 548         }
 549         obj->hdr_size = consumed_bytes - obj->idx.offset;
 550
 551         data = unpack_entry_data(obj->idx.offset, obj->size, obj->type, oid);
 552         obj->idx.crc32 = input_crc32;
 553         return data;
 554 }
 555
 556 static void *unpack_data(struct object_entry *obj,
 557                          int (*consume)(const unsigned char *, unsigned long, void *),
 558                          void *cb_data)
 559 {
 560         off_t from = obj[0].idx.offset + obj[0].hdr_size;
 561         off_t len = obj[1].idx.offset - from;
 562         unsigned char *data, *inbuf;
 563         git_zstream stream;
 564         int status;
 565
 566         data = xmallocz(consume ? 64*1024 : obj->size);
 567         inbuf = xmalloc((len < 64*1024) ? (int)len : 64*1024);
 568
 569         memset(&stream, 0, sizeof(stream));
 570         git_inflate_init(&stream);
 571         stream.next_out = data;
 572         stream.avail_out = consume ? 64*1024 : obj->size;
 573
 574         do {
 575                 ssize_t n = (len < 64*1024) ? (ssize_t)len : 64*1024;
 576                 n = xpread(get_thread_data()->pack_fd, inbuf, n, from);
 577                 if (n < 0)
 578                         die_errno(_("cannot pread pack file"));
 579                 if (!n)
 580                         die(Q_("premature end of pack file, %"PRIuMAX" byte missing",
 581                                "premature end of pack file, %"PRIuMAX" bytes missing",
 582                                (unsigned int)len),
 583                             (uintmax_t)len);
 584                 from += n;
 585                 len -= n;
 586                 stream.next_in = inbuf;
 587                 stream.avail_in = n;
 588                 if (!consume)
 589                         status = git_inflate(&stream, 0);
 590                 else {
 591                         do {
 592                                 status = git_inflate(&stream, 0);
 593                                 if (consume(data, stream.next_out - data, cb_data)) {
 594                                         free(inbuf);
 595                                         free(data);
 596                                         return NULL;
 597                                 }
 598                                 stream.next_out = data;
 599                                 stream.avail_out = 64*1024;
 600                         } while (status == Z_OK && stream.avail_in);
 601                 }
 602         } while (len && status == Z_OK && !stream.avail_in);
 603
 604         /* This has been inflated OK when first encountered, so... */
 605         if (status != Z_STREAM_END || stream.total_out != obj->size)
 606                 die(_("serious inflate inconsistency"));
 607
 608         git_inflate_end(&stream);
 609         free(inbuf);
 610         if (consume) {
 611                 FREE_AND_NULL(data);
 612         }
 613         return data;
 614 }
 615
 616 static void *get_data_from_pack(struct object_entry *obj)
 617 {
 618         return unpack_data(obj, NULL, NULL);
 619 }
 620
 621 static int compare_ofs_delta_bases(off_t offset1, off_t offset2,
 622                                    enum object_type type1,
 623                                    enum object_type type2)
 624 {
 625         int cmp = type1 - type2;
 626         if (cmp)
 627                 return cmp;
 628         return offset1 < offset2 ? -1 :
 629                offset1 > offset2 ?  1 :
 630                0;
 631 }
 632
 633 static int find_ofs_delta(const off_t offset)
 634 {
 635         int first = 0, last = nr_ofs_deltas;
 636
 637         while (first < last) {
 638                 int next = first + (last - first) / 2;
 639                 struct ofs_delta_entry *delta = &ofs_deltas[next];
 640                 int cmp;
 641
 642                 cmp = compare_ofs_delta_bases(offset, delta->offset,
 643                                               OBJ_OFS_DELTA,
 644                                               objects[delta->obj_no].type);
 645                 if (!cmp)
 646                         return next;
 647                 if (cmp < 0) {
 648                         last = next;
 649                         continue;
 650                 }
 651                 first = next+1;
 652         }
 653         return -first-1;
 654 }
 655
 656 static void find_ofs_delta_children(off_t offset,
 657                                     int *first_index, int *last_index)
 658 {
 659         int first = find_ofs_delta(offset);
 660         int last = first;
 661         int end = nr_ofs_deltas - 1;
 662
 663         if (first < 0) {
 664                 *first_index = 0;
 665                 *last_index = -1;
 666                 return;
 667         }
 668         while (first > 0 && ofs_deltas[first - 1].offset == offset)
 669                 --first;
 670         while (last < end && ofs_deltas[last + 1].offset == offset)
 671                 ++last;
 672         *first_index = first;
 673         *last_index = last;
 674 }
 675
 676 static int compare_ref_delta_bases(const struct object_id *oid1,
 677                                    const struct object_id *oid2,
 678                                    enum object_type type1,
 679                                    enum object_type type2)
 680 {
 681         int cmp = type1 - type2;
 682         if (cmp)
 683                 return cmp;
 684         return oidcmp(oid1, oid2);
 685 }
 686
 687 static int find_ref_delta(const struct object_id *oid)
 688 {
 689         int first = 0, last = nr_ref_deltas;
 690
 691         while (first < last) {
 692                 int next = first + (last - first) / 2;
 693                 struct ref_delta_entry *delta = &ref_deltas[next];
 694                 int cmp;
 695
 696                 cmp = compare_ref_delta_bases(oid, &delta->oid,
 697                                               OBJ_REF_DELTA,
 698                                               objects[delta->obj_no].type);
 699                 if (!cmp)
 700                         return next;
 701                 if (cmp < 0) {
 702                         last = next;
 703                         continue;
 704                 }
 705                 first = next+1;
 706         }
 707         return -first-1;
 708 }
 709
 710 static void find_ref_delta_children(const struct object_id *oid,
 711                                     int *first_index, int *last_index)
 712 {
 713         int first = find_ref_delta(oid);
 714         int last = first;
 715         int end = nr_ref_deltas - 1;
 716
 717         if (first < 0) {
 718                 *first_index = 0;
 719                 *last_index = -1;
 720                 return;
 721         }
 722         while (first > 0 && oideq(&ref_deltas[first - 1].oid, oid))
 723                 --first;
 724         while (last < end && oideq(&ref_deltas[last + 1].oid, oid))
 725                 ++last;
 726         *first_index = first;
 727         *last_index = last;
 728 }
 729
 730 struct compare_data {
 731         struct object_entry *entry;
 732         struct git_istream *st;
 733         unsigned char *buf;
 734         unsigned long buf_size;
 735 };
 736
 737 static int compare_objects(const unsigned char *buf, unsigned long size,
 738                            void *cb_data)
 739 {
 740         struct compare_data *data = cb_data;
 741
 742         if (data->buf_size < size) {
 743                 free(data->buf);
 744                 data->buf = xmalloc(size);
 745                 data->buf_size = size;
 746         }
 747
 748         while (size) {
 749                 ssize_t len = read_istream(data->st, data->buf, size);
 750                 if (len == 0)
 751                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 752                             oid_to_hex(&data->entry->idx.oid));
 753                 if (len < 0)
 754                         die(_("unable to read %s"),
 755                             oid_to_hex(&data->entry->idx.oid));
 756                 if (memcmp(buf, data->buf, len))
 757                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 758                             oid_to_hex(&data->entry->idx.oid));
 759                 size -= len;
 760                 buf += len;
 761         }
 762         return 0;
 763 }
 764
 765 static int check_collison(struct object_entry *entry)
 766 {
 767         struct compare_data data;
 768         enum object_type type;
 769         unsigned long size;
 770
 771         if (entry->size <= big_file_threshold || entry->type != OBJ_BLOB)
 772                 return -1;
 773
 774         memset(&data, 0, sizeof(data));
 775         data.entry = entry;
 776         data.st = open_istream(the_repository, &entry->idx.oid, &type, &size,
 777                                NULL);
 778         if (!data.st)
 779                 return -1;
 780         if (size != entry->size || type != entry->type)
 781                 die(_("SHA1 COLLISION FOUND WITH %s !"),
 782                     oid_to_hex(&entry->idx.oid));
 783         unpack_data(entry, compare_objects, &data);
 784         close_istream(data.st);
 785         free(data.buf);
 786         return 0;
 787 }
 788
 789 static void sha1_object(const void *data, struct object_entry *obj_entry,
 790                         unsigned long size, enum object_type type,
 791                         const struct object_id *oid)
 792 {
 793         void *new_data = NULL;
 794         int collision_test_needed = 0;
 795
 796         assert(data || obj_entry);
 797
 798         if (startup_info->have_repository) {
 799                 read_lock();
 800                 collision_test_needed =
 801                         has_object_file_with_flags(oid, OBJECT_INFO_QUICK);
 802                 read_unlock();
 803         }
 804
 805         if (collision_test_needed && !data) {
 806                 read_lock();
 807                 if (!check_collison(obj_entry))
 808                         collision_test_needed = 0;
 809                 read_unlock();
 810         }
 811         if (collision_test_needed) {
 812                 void *has_data;
 813                 enum object_type has_type;
 814                 unsigned long has_size;
 815                 read_lock();
 816                 has_type = oid_object_info(the_repository, oid, &has_size);
 817                 if (has_type < 0)
 818                         die(_("cannot read existing object info %s"), oid_to_hex(oid));
 819                 if (has_type != type || has_size != size)
 820                         die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
 821                 has_data = read_object_file(oid, &has_type, &has_size);
 822                 read_unlock();
 823                 if (!data)
 824                         data = new_data = get_data_from_pack(obj_entry);
 825                 if (!has_data)
 826                         die(_("cannot read existing object %s"), oid_to_hex(oid));
 827                 if (size != has_size || type != has_type ||
 828                     memcmp(data, has_data, size) != 0)
 829                         die(_("SHA1 COLLISION FOUND WITH %s !"), oid_to_hex(oid));
 830                 free(has_data);
 831         }
 832
 833         if (strict || do_fsck_object) {
 834                 read_lock();
 835                 if (type == OBJ_BLOB) {
 836                         struct blob *blob = lookup_blob(the_repository, oid);
 837                         if (blob)
 838                                 blob->object.flags |= FLAG_CHECKED;
 839                         else
 840                                 die(_("invalid blob object %s"), oid_to_hex(oid));
 841                         if (do_fsck_object &&
 842                             fsck_object(&blob->object, (void *)data, size, &fsck_options))
 843                                 die(_("fsck error in packed object"));
 844                 } else {
 845                         struct object *obj;
 846                         int eaten;
 847                         void *buf = (void *) data;
 848
 849                         assert(data && "data can only be NULL for large _blobs_");
 850
 851                         /*
 852                          * we do not need to free the memory here, as the
 853                          * buf is deleted by the caller.
 854                          */
 855                         obj = parse_object_buffer(the_repository, oid, type,
 856                                                   size, buf,
 857                                                   &eaten);
 858                         if (!obj)
 859                                 die(_("invalid %s"), type_name(type));
 860                         if (do_fsck_object &&
 861                             fsck_object(obj, buf, size, &fsck_options))
 862                                 die(_("fsck error in packed object"));
 863                         if (strict && fsck_walk(obj, NULL, &fsck_options))
 864                                 die(_("Not all child objects of %s are reachable"), oid_to_hex(&obj->oid));
 865
 866                         if (obj->type == OBJ_TREE) {
 867                                 struct tree *item = (struct tree *) obj;
 868                                 item->buffer = NULL;
 869                                 obj->parsed = 0;
 870                         }
 871                         if (obj->type == OBJ_COMMIT) {
 872                                 struct commit *commit = (struct commit *) obj;
 873                                 if (detach_commit_buffer(commit, NULL) != data)
 874                                         BUG("parse_object_buffer transmogrified our buffer");
 875                         }
 876                         obj->flags |= FLAG_CHECKED;
 877                 }
 878                 read_unlock();
 879         }
 880
 881         free(new_data);
 882 }
 883
 884 /*
 885  * Ensure that this node has been reconstructed and return its contents.
 886  *
 887  * In the typical and best case, this node would already be reconstructed
 888  * (through the invocation to resolve_delta() in threaded_second_pass()) and it
 889  * would not be pruned. However, if pruning of this node was necessary due to
 890  * reaching delta_base_cache_limit, this function will find the closest
 891  * ancestor with reconstructed data that has not been pruned (or if there is
 892  * none, the ultimate base object), and reconstruct each node in the delta
 893  * chain in order to generate the reconstructed data for this node.
 894  */
 895 static void *get_base_data(struct base_data *c)
 896 {
 897         if (!c->data) {
 898                 struct object_entry *obj = c->obj;
 899                 struct base_data **delta = NULL;
 900                 int delta_nr = 0, delta_alloc = 0;
 901
 902                 while (is_delta_type(c->obj->type) && !c->data) {
 903                         ALLOC_GROW(delta, delta_nr + 1, delta_alloc);
 904                         delta[delta_nr++] = c;
 905                         c = c->base;
 906                 }
 907                 if (!delta_nr) {
 908                         c->data = get_data_from_pack(obj);
 909                         c->size = obj->size;
 910                         base_cache_used += c->size;
 911                         prune_base_data(c);
 912                 }
 913                 for (; delta_nr > 0; delta_nr--) {
 914                         void *base, *raw;
 915                         c = delta[delta_nr - 1];
 916                         obj = c->obj;
 917                         base = get_base_data(c->base);
 918                         raw = get_data_from_pack(obj);
 919                         c->data = patch_delta(
 920                                 base, c->base->size,
 921                                 raw, obj->size,
 922                                 &c->size);
 923                         free(raw);
 924                         if (!c->data)
 925                                 bad_object(obj->idx.offset, _("failed to apply delta"));
 926                         base_cache_used += c->size;
 927                         prune_base_data(c);
 928                 }
 929                 free(delta);
 930         }
 931         return c->data;
 932 }
 933
 934 static struct base_data *make_base(struct object_entry *obj,
 935                                    struct base_data *parent)
 936 {
 937         struct base_data *base = xcalloc(1, sizeof(struct base_data));
 938         base->base = parent;
 939         base->obj = obj;
 940         find_ref_delta_children(&obj->idx.oid,
 941                                 &base->ref_first, &base->ref_last);
 942         find_ofs_delta_children(obj->idx.offset,
 943                                 &base->ofs_first, &base->ofs_last);
 944         base->children_remaining = base->ref_last - base->ref_first +
 945                 base->ofs_last - base->ofs_first + 2;
 946         return base;
 947 }
 948
 949 static struct base_data *resolve_delta(struct object_entry *delta_obj,
 950                                        struct base_data *base)
 951 {
 952         void *delta_data, *result_data;
 953         struct base_data *result;
 954         unsigned long result_size;
 955
 956         if (show_stat) {
 957                 int i = delta_obj - objects;
 958                 int j = base->obj - objects;
 959                 obj_stat[i].delta_depth = obj_stat[j].delta_depth + 1;
 960                 deepest_delta_lock();
 961                 if (deepest_delta < obj_stat[i].delta_depth)
 962                         deepest_delta = obj_stat[i].delta_depth;
 963                 deepest_delta_unlock();
 964                 obj_stat[i].base_object_no = j;
 965         }
 966         delta_data = get_data_from_pack(delta_obj);
 967         assert(base->data);
 968         result_data = patch_delta(base->data, base->size,
 969                                   delta_data, delta_obj->size, &result_size);
 970         free(delta_data);
 971         if (!result_data)
 972                 bad_object(delta_obj->idx.offset, _("failed to apply delta"));
 973         hash_object_file(the_hash_algo, result_data, result_size,
 974                          type_name(delta_obj->real_type), &delta_obj->idx.oid);
 975         sha1_object(result_data, NULL, result_size, delta_obj->real_type,
 976                     &delta_obj->idx.oid);
 977
 978         result = make_base(delta_obj, base);
 979         result->data = result_data;
 980         result->size = result_size;
 981
 982         counter_lock();
 983         nr_resolved_deltas++;
 984         counter_unlock();
 985
 986         return result;
 987 }
 988
 989 static int compare_ofs_delta_entry(const void *a, const void *b)
 990 {
 991         const struct ofs_delta_entry *delta_a = a;
 992         const struct ofs_delta_entry *delta_b = b;
 993
 994         return delta_a->offset < delta_b->offset ? -1 :
 995                delta_a->offset > delta_b->offset ?  1 :
 996                0;
 997 }
 998
 999 static int compare_ref_delta_entry(const void *a, const void *b)
1000 {
1001         const struct ref_delta_entry *delta_a = a;
1002         const struct ref_delta_entry *delta_b = b;
1003
1004         return oidcmp(&delta_a->oid, &delta_b->oid);
1005 }
1006
1007 static void *threaded_second_pass(void *data)
1008 {
1009         if (data)
1010                 set_thread_data(data);
1011         for (;;) {
1012                 struct base_data *parent = NULL;
1013                 struct object_entry *child_obj;
1014                 struct base_data *child;
1015
1016                 counter_lock();
1017                 display_progress(progress, nr_resolved_deltas);
1018                 counter_unlock();
1019
1020                 work_lock();
1021                 if (list_empty(&work_head)) {
1022                         /*
1023                          * Take an object from the object array.
1024                          */
1025                         while (nr_dispatched < nr_objects &&
1026                                is_delta_type(objects[nr_dispatched].type))
1027                                 nr_dispatched++;
1028                         if (nr_dispatched >= nr_objects) {
1029                                 work_unlock();
1030                                 break;
1031                         }
1032                         child_obj = &objects[nr_dispatched++];
1033                 } else {
1034                         /*
1035                          * Peek at the top of the stack, and take a child from
1036                          * it.
1037                          */
1038                         parent = list_first_entry(&work_head, struct base_data,
1039                                                   list);
1040
1041                         if (parent->ref_first <= parent->ref_last) {
1042                                 int offset = ref_deltas[parent->ref_first++].obj_no;
1043                                 child_obj = objects + offset;
1044                                 if (child_obj->real_type != OBJ_REF_DELTA)
1045                                         die("REF_DELTA at offset %"PRIuMAX" already resolved (duplicate base %s?)",
1046                                             (uintmax_t) child_obj->idx.offset,
1047                                             oid_to_hex(&parent->obj->idx.oid));
1048                                 child_obj->real_type = parent->obj->real_type;
1049                         } else {
1050                                 child_obj = objects +
1051                                         ofs_deltas[parent->ofs_first++].obj_no;
1052                                 assert(child_obj->real_type == OBJ_OFS_DELTA);
1053                                 child_obj->real_type = parent->obj->real_type;
1054                         }
1055
1056                         if (parent->ref_first > parent->ref_last &&
1057                             parent->ofs_first > parent->ofs_last) {
1058                                 /*
1059                                  * This parent has run out of children, so move
1060                                  * it to done_head.
1061                                  */
1062                                 list_del(&parent->list);
1063                                 list_add(&parent->list, &done_head);
1064                         }
1065
1066                         /*
1067                          * Ensure that the parent has data, since we will need
1068                          * it later.
1069                          *
1070                          * NEEDSWORK: If parent data needs to be reloaded, this
1071                          * prolongs the time that the current thread spends in
1072                          * the mutex. A mitigating factor is that parent data
1073                          * needs to be reloaded only if the delta base cache
1074                          * limit is exceeded, so in the typical case, this does
1075                          * not happen.
1076                          */
1077                         get_base_data(parent);
1078                         parent->retain_data++;
1079                 }
1080                 work_unlock();
1081
1082                 if (parent) {
1083                         child = resolve_delta(child_obj, parent);
1084                         if (!child->children_remaining)
1085                                 FREE_AND_NULL(child->data);
1086                 } else {
1087                         child = make_base(child_obj, NULL);
1088                         if (child->children_remaining) {
1089                                 /*
1090                                  * Since this child has its own delta children,
1091                                  * we will need this data in the future.
1092                                  * Inflate now so that future iterations will
1093                                  * have access to this object's data while
1094                                  * outside the work mutex.
1095                                  */
1096                                 child->data = get_data_from_pack(child_obj);
1097                                 child->size = child_obj->size;
1098                         }
1099                 }
1100
1101                 work_lock();
1102                 if (parent)
1103                         parent->retain_data--;
1104                 if (child->data) {
1105                         /*
1106                          * This child has its own children, so add it to
1107                          * work_head.
1108                          */
1109                         list_add(&child->list, &work_head);
1110                         base_cache_used += child->size;
1111                         prune_base_data(NULL);
1112                 } else {
1113                         /*
1114                          * This child does not have its own children. It may be
1115                          * the last descendant of its ancestors; free those
1116                          * that we can.
1117                          */
1118                         struct base_data *p = parent;
1119
1120                         while (p) {
1121                                 struct base_data *next_p;
1122
1123                                 p->children_remaining--;
1124                                 if (p->children_remaining)
1125                                         break;
1126
1127                                 next_p = p->base;
1128                                 free_base_data(p);
1129                                 list_del(&p->list);
1130                                 free(p);
1131
1132                                 p = next_p;
1133                         }
1134                 }
1135                 work_unlock();
1136         }
1137         return NULL;
1138 }
1139
1140 /*
1141  * First pass:
1142  * - find locations of all objects;
1143  * - calculate SHA1 of all non-delta objects;
1144  * - remember base (SHA1 or offset) for all deltas.
1145  */
1146 static void parse_pack_objects(unsigned char *hash)
1147 {
1148         int i, nr_delays = 0;
1149         struct ofs_delta_entry *ofs_delta = ofs_deltas;
1150         struct object_id ref_delta_oid;
1151         struct stat st;
1152
1153         if (verbose)
1154                 progress = start_progress(
1155                                 progress_title ? progress_title :
1156                                 from_stdin ? _("Receiving objects") : _("Indexing objects"),
1157                                 nr_objects);
1158         for (i = 0; i < nr_objects; i++) {
1159                 struct object_entry *obj = &objects[i];
1160                 void *data = unpack_raw_entry(obj, &ofs_delta->offset,
1161                                               &ref_delta_oid,
1162                                               &obj->idx.oid);
1163                 obj->real_type = obj->type;
1164                 if (obj->type == OBJ_OFS_DELTA) {
1165                         nr_ofs_deltas++;
1166                         ofs_delta->obj_no = i;
1167                         ofs_delta++;
1168                 } else if (obj->type == OBJ_REF_DELTA) {
1169                         ALLOC_GROW(ref_deltas, nr_ref_deltas + 1, ref_deltas_alloc);
1170                         oidcpy(&ref_deltas[nr_ref_deltas].oid, &ref_delta_oid);
1171                         ref_deltas[nr_ref_deltas].obj_no = i;
1172                         nr_ref_deltas++;
1173                 } else if (!data) {
1174                         /* large blobs, check later */
1175                         obj->real_type = OBJ_BAD;
1176                         nr_delays++;
1177                 } else
1178                         sha1_object(data, NULL, obj->size, obj->type,
1179                                     &obj->idx.oid);
1180                 free(data);
1181                 display_progress(progress, i+1);
1182         }
1183         objects[i].idx.offset = consumed_bytes;
1184         stop_progress(&progress);
1185
1186         /* Check pack integrity */
1187         flush();
1188         the_hash_algo->final_fn(hash, &input_ctx);
1189         if (!hasheq(fill(the_hash_algo->rawsz), hash))
1190                 die(_("pack is corrupted (SHA1 mismatch)"));
1191         use(the_hash_algo->rawsz);
1192
1193         /* If input_fd is a file, we should have reached its end now. */
1194         if (fstat(input_fd, &st))
1195                 die_errno(_("cannot fstat packfile"));
1196         if (S_ISREG(st.st_mode) &&
1197                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
1198                 die(_("pack has junk at the end"));
1199
1200         for (i = 0; i < nr_objects; i++) {
1201                 struct object_entry *obj = &objects[i];
1202                 if (obj->real_type != OBJ_BAD)
1203                         continue;
1204                 obj->real_type = obj->type;
1205                 sha1_object(NULL, obj, obj->size, obj->type,
1206                             &obj->idx.oid);
1207                 nr_delays--;
1208         }
1209         if (nr_delays)
1210                 die(_("confusion beyond insanity in parse_pack_objects()"));
1211 }
1212
1213 /*
1214  * Second pass:
1215  * - for all non-delta objects, look if it is used as a base for
1216  *   deltas;
1217  * - if used as a base, uncompress the object and apply all deltas,
1218  *   recursively checking if the resulting object is used as a base
1219  *   for some more deltas.
1220  */
1221 static void resolve_deltas(void)
1222 {
1223         int i;
1224
1225         if (!nr_ofs_deltas && !nr_ref_deltas)
1226                 return;
1227
1228         /* Sort deltas by base SHA1/offset for fast searching */
1229         QSORT(ofs_deltas, nr_ofs_deltas, compare_ofs_delta_entry);
1230         QSORT(ref_deltas, nr_ref_deltas, compare_ref_delta_entry);
1231
1232         if (verbose || show_resolving_progress)
1233                 progress = start_progress(_("Resolving deltas"),
1234                                           nr_ref_deltas + nr_ofs_deltas);
1235
1236         nr_dispatched = 0;
1237         base_cache_limit = delta_base_cache_limit * nr_threads;
1238         if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) {
1239                 init_thread();
1240                 for (i = 0; i < nr_threads; i++) {
1241                         int ret = pthread_create(&thread_data[i].thread, NULL,
1242                                                  threaded_second_pass, thread_data + i);
1243                         if (ret)
1244                                 die(_("unable to create thread: %s"),
1245                                     strerror(ret));
1246                 }
1247                 for (i = 0; i < nr_threads; i++)
1248                         pthread_join(thread_data[i].thread, NULL);
1249                 cleanup_thread();
1250                 return;
1251         }
1252         threaded_second_pass(&nothread_data);
1253 }
1254
1255 /*
1256  * Third pass:
1257  * - append objects to convert thin pack to full pack if required
1258  * - write the final pack hash
1259  */
1260 static void fix_unresolved_deltas(struct hashfile *f);
1261 static void conclude_pack(int fix_thin_pack, const char *curr_pack, unsigned char *pack_hash)
1262 {
1263         if (nr_ref_deltas + nr_ofs_deltas == nr_resolved_deltas) {
1264                 stop_progress(&progress);
1265                 /* Flush remaining pack final hash. */
1266                 flush();
1267                 return;
1268         }
1269
1270         if (fix_thin_pack) {
1271                 struct hashfile *f;
1272                 unsigned char read_hash[GIT_MAX_RAWSZ], tail_hash[GIT_MAX_RAWSZ];
1273                 struct strbuf msg = STRBUF_INIT;
1274                 int nr_unresolved = nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas;
1275                 int nr_objects_initial = nr_objects;
1276                 if (nr_unresolved <= 0)
1277                         die(_("confusion beyond insanity"));
1278                 REALLOC_ARRAY(objects, nr_objects + nr_unresolved + 1);
1279                 memset(objects + nr_objects + 1, 0,
1280                        nr_unresolved * sizeof(*objects));
1281                 f = hashfd(output_fd, curr_pack);
1282                 fix_unresolved_deltas(f);
1283                 strbuf_addf(&msg, Q_("completed with %d local object",
1284                                      "completed with %d local objects",
1285                                      nr_objects - nr_objects_initial),
1286                             nr_objects - nr_objects_initial);
1287                 stop_progress_msg(&progress, msg.buf);
1288                 strbuf_release(&msg);
1289                 finalize_hashfile(f, tail_hash, 0);
1290                 hashcpy(read_hash, pack_hash);
1291                 fixup_pack_header_footer(output_fd, pack_hash,
1292                                          curr_pack, nr_objects,
1293                                          read_hash, consumed_bytes-the_hash_algo->rawsz);
1294                 if (!hasheq(read_hash, tail_hash))
1295                         die(_("Unexpected tail checksum for %s "
1296                               "(disk corruption?)"), curr_pack);
1297         }
1298         if (nr_ofs_deltas + nr_ref_deltas != nr_resolved_deltas)
1299                 die(Q_("pack has %d unresolved delta",
1300                        "pack has %d unresolved deltas",
1301                        nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas),
1302                     nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas);
1303 }
1304
1305 static int write_compressed(struct hashfile *f, void *in, unsigned int size)
1306 {
1307         git_zstream stream;
1308         int status;
1309         unsigned char outbuf[4096];
1310
1311         git_deflate_init(&stream, zlib_compression_level);
1312         stream.next_in = in;
1313         stream.avail_in = size;
1314
1315         do {
1316                 stream.next_out = outbuf;
1317                 stream.avail_out = sizeof(outbuf);
1318                 status = git_deflate(&stream, Z_FINISH);
1319                 hashwrite(f, outbuf, sizeof(outbuf) - stream.avail_out);
1320         } while (status == Z_OK);
1321
1322         if (status != Z_STREAM_END)
1323                 die(_("unable to deflate appended object (%d)"), status);
1324         size = stream.total_out;
1325         git_deflate_end(&stream);
1326         return size;
1327 }
1328
1329 static struct object_entry *append_obj_to_pack(struct hashfile *f,
1330                                const unsigned char *sha1, void *buf,
1331                                unsigned long size, enum object_type type)
1332 {
1333         struct object_entry *obj = &objects[nr_objects++];
1334         unsigned char header[10];
1335         unsigned long s = size;
1336         int n = 0;
1337         unsigned char c = (type << 4) | (s & 15);
1338         s >>= 4;
1339         while (s) {
1340                 header[n++] = c | 0x80;
1341                 c = s & 0x7f;
1342                 s >>= 7;
1343         }
1344         header[n++] = c;
1345         crc32_begin(f);
1346         hashwrite(f, header, n);
1347         obj[0].size = size;
1348         obj[0].hdr_size = n;
1349         obj[0].type = type;
1350         obj[0].real_type = type;
1351         obj[1].idx.offset = obj[0].idx.offset + n;
1352         obj[1].idx.offset += write_compressed(f, buf, size);
1353         obj[0].idx.crc32 = crc32_end(f);
1354         hashflush(f);
1355         oidread(&obj->idx.oid, sha1);
1356         return obj;
1357 }
1358
1359 static int delta_pos_compare(const void *_a, const void *_b)
1360 {
1361         struct ref_delta_entry *a = *(struct ref_delta_entry **)_a;
1362         struct ref_delta_entry *b = *(struct ref_delta_entry **)_b;
1363         return a->obj_no - b->obj_no;
1364 }
1365
1366 static void fix_unresolved_deltas(struct hashfile *f)
1367 {
1368         struct ref_delta_entry **sorted_by_pos;
1369         int i;
1370
1371         /*
1372          * Since many unresolved deltas may well be themselves base objects
1373          * for more unresolved deltas, we really want to include the
1374          * smallest number of base objects that would cover as much delta
1375          * as possible by picking the
1376          * trunc deltas first, allowing for other deltas to resolve without
1377          * additional base objects.  Since most base objects are to be found
1378          * before deltas depending on them, a good heuristic is to start
1379          * resolving deltas in the same order as their position in the pack.
1380          */
1381         ALLOC_ARRAY(sorted_by_pos, nr_ref_deltas);
1382         for (i = 0; i < nr_ref_deltas; i++)
1383                 sorted_by_pos[i] = &ref_deltas[i];
1384         QSORT(sorted_by_pos, nr_ref_deltas, delta_pos_compare);
1385
1386         if (has_promisor_remote()) {
1387                 /*
1388                  * Prefetch the delta bases.
1389                  */
1390                 struct oid_array to_fetch = OID_ARRAY_INIT;
1391                 for (i = 0; i < nr_ref_deltas; i++) {
1392                         struct ref_delta_entry *d = sorted_by_pos[i];
1393                         if (!oid_object_info_extended(the_repository, &d->oid,
1394                                                       NULL,
1395                                                       OBJECT_INFO_FOR_PREFETCH))
1396                                 continue;
1397                         oid_array_append(&to_fetch, &d->oid);
1398                 }
1399                 promisor_remote_get_direct(the_repository,
1400                                            to_fetch.oid, to_fetch.nr);
1401                 oid_array_clear(&to_fetch);
1402         }
1403
1404         for (i = 0; i < nr_ref_deltas; i++) {
1405                 struct ref_delta_entry *d = sorted_by_pos[i];
1406                 enum object_type type;
1407                 void *data;
1408                 unsigned long size;
1409
1410                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
1411                         continue;
1412                 data = read_object_file(&d->oid, &type, &size);
1413                 if (!data)
1414                         continue;
1415
1416                 if (check_object_signature(the_repository, &d->oid,
1417                                            data, size,
1418                                            type_name(type), NULL))
1419                         die(_("local object %s is corrupt"), oid_to_hex(&d->oid));
1420
1421                 /*
1422                  * Add this as an object to the objects array and call
1423                  * threaded_second_pass() (which will pick up the added
1424                  * object).
1425                  */
1426                 append_obj_to_pack(f, d->oid.hash, data, size, type);
1427                 threaded_second_pass(NULL);
1428
1429                 display_progress(progress, nr_resolved_deltas);
1430         }
1431         free(sorted_by_pos);
1432 }
1433
1434 static const char *derive_filename(const char *pack_name, const char *strip,
1435                                    const char *suffix, struct strbuf *buf)
1436 {
1437         size_t len;
1438         if (!strip_suffix(pack_name, strip, &len) || !len ||
1439             pack_name[len - 1] != '.')
1440                 die(_("packfile name '%s' does not end with '.%s'"),
1441                     pack_name, strip);
1442         strbuf_add(buf, pack_name, len);
1443         strbuf_addstr(buf, suffix);
1444         return buf->buf;
1445 }
1446
1447 static void write_special_file(const char *suffix, const char *msg,
1448                                const char *pack_name, const unsigned char *hash,
1449                                const char **report)
1450 {
1451         struct strbuf name_buf = STRBUF_INIT;
1452         const char *filename;
1453         int fd;
1454         int msg_len = strlen(msg);
1455
1456         if (pack_name)
1457                 filename = derive_filename(pack_name, "pack", suffix, &name_buf);
1458         else
1459                 filename = odb_pack_name(&name_buf, hash, suffix);
1460
1461         fd = odb_pack_keep(filename);
1462         if (fd < 0) {
1463                 if (errno != EEXIST)
1464                         die_errno(_("cannot write %s file '%s'"),
1465                                   suffix, filename);
1466         } else {
1467                 if (msg_len > 0) {
1468                         write_or_die(fd, msg, msg_len);
1469                         write_or_die(fd, "\n", 1);
1470                 }
1471                 if (close(fd) != 0)
1472                         die_errno(_("cannot close written %s file '%s'"),
1473                                   suffix, filename);
1474                 if (report)
1475                         *report = suffix;
1476         }
1477         strbuf_release(&name_buf);
1478 }
1479
1480 static void rename_tmp_packfile(const char **final_name,
1481                                 const char *curr_name,
1482                                 struct strbuf *name, unsigned char *hash,
1483                                 const char *ext, int make_read_only_if_same)
1484 {
1485         if (*final_name != curr_name) {
1486                 if (!*final_name)
1487                         *final_name = odb_pack_name(name, hash, ext);
1488                 if (finalize_object_file(curr_name, *final_name))
1489                         die(_("unable to rename temporary '*.%s' file to '%s'"),
1490                             ext, *final_name);
1491         } else if (make_read_only_if_same) {
1492                 chmod(*final_name, 0444);
1493         }
1494 }
1495
1496 static void final(const char *final_pack_name, const char *curr_pack_name,
1497                   const char *final_index_name, const char *curr_index_name,
1498                   const char *final_rev_index_name, const char *curr_rev_index_name,
1499                   const char *keep_msg, const char *promisor_msg,
1500                   unsigned char *hash)
1501 {
1502         const char *report = "pack";
1503         struct strbuf pack_name = STRBUF_INIT;
1504         struct strbuf index_name = STRBUF_INIT;
1505         struct strbuf rev_index_name = STRBUF_INIT;
1506         int err;
1507
1508         if (!from_stdin) {
1509                 close(input_fd);
1510         } else {
1511                 fsync_or_die(output_fd, curr_pack_name);
1512                 err = close(output_fd);
1513                 if (err)
1514                         die_errno(_("error while closing pack file"));
1515         }
1516
1517         if (keep_msg)
1518                 write_special_file("keep", keep_msg, final_pack_name, hash,
1519                                    &report);
1520         if (promisor_msg)
1521                 write_special_file("promisor", promisor_msg, final_pack_name,
1522                                    hash, NULL);
1523
1524         rename_tmp_packfile(&final_pack_name, curr_pack_name, &pack_name,
1525                             hash, "pack", from_stdin);
1526         if (curr_rev_index_name)
1527                 rename_tmp_packfile(&final_rev_index_name, curr_rev_index_name,
1528                                     &rev_index_name, hash, "rev", 1);
1529         rename_tmp_packfile(&final_index_name, curr_index_name, &index_name,
1530                             hash, "idx", 1);
1531
1532         if (do_fsck_object) {
1533                 struct packed_git *p;
1534                 p = add_packed_git(final_index_name, strlen(final_index_name), 0);
1535                 if (p)
1536                         install_packed_git(the_repository, p);
1537         }
1538
1539         if (!from_stdin) {
1540                 printf("%s\n", hash_to_hex(hash));
1541         } else {
1542                 struct strbuf buf = STRBUF_INIT;
1543
1544                 strbuf_addf(&buf, "%s\t%s\n", report, hash_to_hex(hash));
1545                 write_or_die(1, buf.buf, buf.len);
1546                 strbuf_release(&buf);
1547
1548                 /*
1549                  * Let's just mimic git-unpack-objects here and write
1550                  * the last part of the input buffer to stdout.
1551                  */
1552                 while (input_len) {
1553                         err = xwrite(1, input_buffer + input_offset, input_len);
1554                         if (err <= 0)
1555                                 break;
1556                         input_len -= err;
1557                         input_offset += err;
1558                 }
1559         }
1560
1561         strbuf_release(&rev_index_name);
1562         strbuf_release(&index_name);
1563         strbuf_release(&pack_name);
1564 }
1565
1566 static int git_index_pack_config(const char *k, const char *v, void *cb)
1567 {
1568         struct pack_idx_option *opts = cb;
1569
1570         if (!strcmp(k, "pack.indexversion")) {
1571                 opts->version = git_config_int(k, v);
1572                 if (opts->version > 2)
1573                         die(_("bad pack.indexversion=%"PRIu32), opts->version);
1574                 return 0;
1575         }
1576         if (!strcmp(k, "pack.threads")) {
1577                 nr_threads = git_config_int(k, v);
1578                 if (nr_threads < 0)
1579                         die(_("invalid number of threads specified (%d)"),
1580                             nr_threads);
1581                 if (!HAVE_THREADS && nr_threads != 1) {
1582                         warning(_("no threads support, ignoring %s"), k);
1583                         nr_threads = 1;
1584                 }
1585                 return 0;
1586         }
1587         if (!strcmp(k, "pack.writereverseindex")) {
1588                 if (git_config_bool(k, v))
1589                         opts->flags |= WRITE_REV;
1590                 else
1591                         opts->flags &= ~WRITE_REV;
1592         }
1593         return git_default_config(k, v, cb);
1594 }
1595
1596 static int cmp_uint32(const void *a_, const void *b_)
1597 {
1598         uint32_t a = *((uint32_t *)a_);
1599         uint32_t b = *((uint32_t *)b_);
1600
1601         return (a < b) ? -1 : (a != b);
1602 }
1603
1604 static void read_v2_anomalous_offsets(struct packed_git *p,
1605                                       struct pack_idx_option *opts)
1606 {
1607         const uint32_t *idx1, *idx2;
1608         uint32_t i;
1609
1610         /* The address of the 4-byte offset table */
1611         idx1 = (((const uint32_t *)((const uint8_t *)p->index_data + p->crc_offset))
1612                 + (size_t)p->num_objects /* CRC32 table */
1613                 );
1614
1615         /* The address of the 8-byte offset table */
1616         idx2 = idx1 + p->num_objects;
1617
1618         for (i = 0; i < p->num_objects; i++) {
1619                 uint32_t off = ntohl(idx1[i]);
1620                 if (!(off & 0x80000000))
1621                         continue;
1622                 off = off & 0x7fffffff;
1623                 check_pack_index_ptr(p, &idx2[off * 2]);
1624                 if (idx2[off * 2])
1625                         continue;
1626                 /*
1627                  * The real offset is ntohl(idx2[off * 2]) in high 4
1628                  * octets, and ntohl(idx2[off * 2 + 1]) in low 4
1629                  * octets.  But idx2[off * 2] is Zero!!!
1630                  */
1631                 ALLOC_GROW(opts->anomaly, opts->anomaly_nr + 1, opts->anomaly_alloc);
1632                 opts->anomaly[opts->anomaly_nr++] = ntohl(idx2[off * 2 + 1]);
1633         }
1634
1635         QSORT(opts->anomaly, opts->anomaly_nr, cmp_uint32);
1636 }
1637
1638 static void read_idx_option(struct pack_idx_option *opts, const char *pack_name)
1639 {
1640         struct packed_git *p = add_packed_git(pack_name, strlen(pack_name), 1);
1641
1642         if (!p)
1643                 die(_("Cannot open existing pack file '%s'"), pack_name);
1644         if (open_pack_index(p))
1645                 die(_("Cannot open existing pack idx file for '%s'"), pack_name);
1646
1647         /* Read the attributes from the existing idx file */
1648         opts->version = p->index_version;
1649
1650         if (opts->version == 2)
1651                 read_v2_anomalous_offsets(p, opts);
1652
1653         /*
1654          * Get rid of the idx file as we do not need it anymore.
1655          * NEEDSWORK: extract this bit from free_pack_by_name() in
1656          * object-file.c, perhaps?  It shouldn't matter very much as we
1657          * know we haven't installed this pack (hence we never have
1658          * read anything from it).
1659          */
1660         close_pack_index(p);
1661         free(p);
1662 }
1663
1664 static void show_pack_info(int stat_only)
1665 {
1666         int i, baseobjects = nr_objects - nr_ref_deltas - nr_ofs_deltas;
1667         unsigned long *chain_histogram = NULL;
1668
1669         if (deepest_delta)
1670                 CALLOC_ARRAY(chain_histogram, deepest_delta);
1671
1672         for (i = 0; i < nr_objects; i++) {
1673                 struct object_entry *obj = &objects[i];
1674
1675                 if (is_delta_type(obj->type))
1676                         chain_histogram[obj_stat[i].delta_depth - 1]++;
1677                 if (stat_only)
1678                         continue;
1679                 printf("%s %-6s %"PRIuMAX" %"PRIuMAX" %"PRIuMAX,
1680                        oid_to_hex(&obj->idx.oid),
1681                        type_name(obj->real_type), (uintmax_t)obj->size,
1682                        (uintmax_t)(obj[1].idx.offset - obj->idx.offset),
1683                        (uintmax_t)obj->idx.offset);
1684                 if (is_delta_type(obj->type)) {
1685                         struct object_entry *bobj = &objects[obj_stat[i].base_object_no];
1686                         printf(" %u %s", obj_stat[i].delta_depth,
1687                                oid_to_hex(&bobj->idx.oid));
1688                 }
1689                 putchar('\n');
1690         }
1691
1692         if (baseobjects)
1693                 printf_ln(Q_("non delta: %d object",
1694                              "non delta: %d objects",
1695                              baseobjects),
1696                           baseobjects);
1697         for (i = 0; i < deepest_delta; i++) {
1698                 if (!chain_histogram[i])
1699                         continue;
1700                 printf_ln(Q_("chain length = %d: %lu object",
1701                              "chain length = %d: %lu objects",
1702                              chain_histogram[i]),
1703                           i + 1,
1704                           chain_histogram[i]);
1705         }
1706 }
1707
1708 int cmd_index_pack(int argc, const char **argv, const char *prefix)
1709 {
1710         int i, fix_thin_pack = 0, verify = 0, stat_only = 0, rev_index;
1711         const char *curr_index;
1712         const char *curr_rev_index = NULL;
1713         const char *index_name = NULL, *pack_name = NULL, *rev_index_name = NULL;
1714         const char *keep_msg = NULL;
1715         const char *promisor_msg = NULL;
1716         struct strbuf index_name_buf = STRBUF_INIT;
1717         struct strbuf rev_index_name_buf = STRBUF_INIT;
1718         struct pack_idx_entry **idx_objects;
1719         struct pack_idx_option opts;
1720         unsigned char pack_hash[GIT_MAX_RAWSZ];
1721         unsigned foreign_nr = 1;        /* zero is a "good" value, assume bad */
1722         int report_end_of_input = 0;
1723         int hash_algo = 0;
1724
1725         /*
1726          * index-pack never needs to fetch missing objects except when
1727          * REF_DELTA bases are missing (which are explicitly handled). It only
1728          * accesses the repo to do hash collision checks and to check which
1729          * REF_DELTA bases need to be fetched.
1730          */
1731         fetch_if_missing = 0;
1732
1733         if (argc == 2 && !strcmp(argv[1], "-h"))
1734                 usage(index_pack_usage);
1735
1736         read_replace_refs = 0;
1737         fsck_options.walk = mark_link;
1738
1739         reset_pack_idx_option(&opts);
1740         git_config(git_index_pack_config, &opts);
1741         if (prefix && chdir(prefix))
1742                 die(_("Cannot come back to cwd"));
1743
1744         if (git_env_bool(GIT_TEST_WRITE_REV_INDEX, 0))
1745                 rev_index = 1;
1746         else
1747                 rev_index = !!(opts.flags & (WRITE_REV_VERIFY | WRITE_REV));
1748
1749         for (i = 1; i < argc; i++) {
1750                 const char *arg = argv[i];
1751
1752                 if (*arg == '-') {
1753                         if (!strcmp(arg, "--stdin")) {
1754                                 from_stdin = 1;
1755                         } else if (!strcmp(arg, "--fix-thin")) {
1756                                 fix_thin_pack = 1;
1757                         } else if (skip_to_optional_arg(arg, "--strict", &arg)) {
1758                                 strict = 1;
1759                                 do_fsck_object = 1;
1760                                 fsck_set_msg_types(&fsck_options, arg);
1761                         } else if (!strcmp(arg, "--check-self-contained-and-connected")) {
1762                                 strict = 1;
1763                                 check_self_contained_and_connected = 1;
1764                         } else if (!strcmp(arg, "--fsck-objects")) {
1765                                 do_fsck_object = 1;
1766                         } else if (!strcmp(arg, "--verify")) {
1767                                 verify = 1;
1768                         } else if (!strcmp(arg, "--verify-stat")) {
1769                                 verify = 1;
1770                                 show_stat = 1;
1771                         } else if (!strcmp(arg, "--verify-stat-only")) {
1772                                 verify = 1;
1773                                 show_stat = 1;
1774                                 stat_only = 1;
1775                         } else if (skip_to_optional_arg(arg, "--keep", &keep_msg)) {
1776                                 ; /* nothing to do */
1777                         } else if (skip_to_optional_arg(arg, "--promisor", &promisor_msg)) {
1778                                 ; /* already parsed */
1779                         } else if (starts_with(arg, "--threads=")) {
1780                                 char *end;
1781                                 nr_threads = strtoul(arg+10, &end, 0);
1782                                 if (!arg[10] || *end || nr_threads < 0)
1783                                         usage(index_pack_usage);
1784                                 if (!HAVE_THREADS && nr_threads != 1) {
1785                                         warning(_("no threads support, ignoring %s"), arg);
1786                                         nr_threads = 1;
1787                                 }
1788                         } else if (starts_with(arg, "--pack_header=")) {
1789                                 struct pack_header *hdr;
1790                                 char *c;
1791
1792                                 hdr = (struct pack_header *)input_buffer;
1793                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
1794                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
1795                                 if (*c != ',')
1796                                         die(_("bad %s"), arg);
1797                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
1798                                 if (*c)
1799                                         die(_("bad %s"), arg);
1800                                 input_len = sizeof(*hdr);
1801                         } else if (!strcmp(arg, "-v")) {
1802                                 verbose = 1;
1803                         } else if (!strcmp(arg, "--progress-title")) {
1804                                 if (progress_title || (i+1) >= argc)
1805                                         usage(index_pack_usage);
1806                                 progress_title = argv[++i];
1807                         } else if (!strcmp(arg, "--show-resolving-progress")) {
1808                                 show_resolving_progress = 1;
1809                         } else if (!strcmp(arg, "--report-end-of-input")) {
1810                                 report_end_of_input = 1;
1811                         } else if (!strcmp(arg, "-o")) {
1812                                 if (index_name || (i+1) >= argc)
1813                                         usage(index_pack_usage);
1814                                 index_name = argv[++i];
1815                         } else if (starts_with(arg, "--index-version=")) {
1816                                 char *c;
1817                                 opts.version = strtoul(arg + 16, &c, 10);
1818                                 if (opts.version > 2)
1819                                         die(_("bad %s"), arg);
1820                                 if (*c == ',')
1821                                         opts.off32_limit = strtoul(c+1, &c, 0);
1822                                 if (*c || opts.off32_limit & 0x80000000)
1823                                         die(_("bad %s"), arg);
1824                         } else if (skip_prefix(arg, "--max-input-size=", &arg)) {
1825                                 max_input_size = strtoumax(arg, NULL, 10);
1826                         } else if (skip_prefix(arg, "--object-format=", &arg)) {
1827                                 hash_algo = hash_algo_by_name(arg);
1828                                 if (hash_algo == GIT_HASH_UNKNOWN)
1829                                         die(_("unknown hash algorithm '%s'"), arg);
1830                                 repo_set_hash_algo(the_repository, hash_algo);
1831                         } else if (!strcmp(arg, "--rev-index")) {
1832                                 rev_index = 1;
1833                         } else if (!strcmp(arg, "--no-rev-index")) {
1834                                 rev_index = 0;
1835                         } else
1836                                 usage(index_pack_usage);
1837                         continue;
1838                 }
1839
1840                 if (pack_name)
1841                         usage(index_pack_usage);
1842                 pack_name = arg;
1843         }
1844
1845         if (!pack_name && !from_stdin)
1846                 usage(index_pack_usage);
1847         if (fix_thin_pack && !from_stdin)
1848                 die(_("the option '%s' requires '%s'"), "--fix-thin", "--stdin");
1849         if (from_stdin && !startup_info->have_repository)
1850                 die(_("--stdin requires a git repository"));
1851         if (from_stdin && hash_algo)
1852                 die(_("options '%s' and '%s' cannot be used together"), "--object-format", "--stdin");
1853         if (!index_name && pack_name)
1854                 index_name = derive_filename(pack_name, "pack", "idx", &index_name_buf);
1855
1856         opts.flags &= ~(WRITE_REV | WRITE_REV_VERIFY);
1857         if (rev_index) {
1858                 opts.flags |= verify ? WRITE_REV_VERIFY : WRITE_REV;
1859                 if (index_name)
1860                         rev_index_name = derive_filename(index_name,
1861                                                          "idx", "rev",
1862                                                          &rev_index_name_buf);
1863         }
1864
1865         if (verify) {
1866                 if (!index_name)
1867                         die(_("--verify with no packfile name given"));
1868                 read_idx_option(&opts, index_name);
1869                 opts.flags |= WRITE_IDX_VERIFY | WRITE_IDX_STRICT;
1870         }
1871         if (strict)
1872                 opts.flags |= WRITE_IDX_STRICT;
1873
1874         if (HAVE_THREADS && !nr_threads) {
1875                 nr_threads = online_cpus();
1876                 /*
1877                  * Experiments show that going above 20 threads doesn't help,
1878                  * no matter how many cores you have. Below that, we tend to
1879                  * max at half the number of online_cpus(), presumably because
1880                  * half of those are hyperthreads rather than full cores. We'll
1881                  * never reduce the level below "3", though, to match a
1882                  * historical value that nobody complained about.
1883                  */
1884                 if (nr_threads < 4)
1885                         ; /* too few cores to consider capping */
1886                 else if (nr_threads < 6)
1887                         nr_threads = 3; /* historic cap */
1888                 else if (nr_threads < 40)
1889                         nr_threads /= 2;
1890                 else
1891                         nr_threads = 20; /* hard cap */
1892         }
1893
1894         curr_pack = open_pack_file(pack_name);
1895         parse_pack_header();
1896         CALLOC_ARRAY(objects, st_add(nr_objects, 1));
1897         if (show_stat)
1898                 CALLOC_ARRAY(obj_stat, st_add(nr_objects, 1));
1899         CALLOC_ARRAY(ofs_deltas, nr_objects);
1900         parse_pack_objects(pack_hash);
1901         if (report_end_of_input)
1902                 write_in_full(2, "\0", 1);
1903         resolve_deltas();
1904         conclude_pack(fix_thin_pack, curr_pack, pack_hash);
1905         free(ofs_deltas);
1906         free(ref_deltas);
1907         if (strict)
1908                 foreign_nr = check_objects();
1909
1910         if (show_stat)
1911                 show_pack_info(stat_only);
1912
1913         ALLOC_ARRAY(idx_objects, nr_objects);
1914         for (i = 0; i < nr_objects; i++)
1915                 idx_objects[i] = &objects[i].idx;
1916         curr_index = write_idx_file(index_name, idx_objects, nr_objects, &opts, pack_hash);
1917         if (rev_index)
1918                 curr_rev_index = write_rev_file(rev_index_name, idx_objects,
1919                                                 nr_objects, pack_hash,
1920                                                 opts.flags);
1921         free(idx_objects);
1922
1923         if (!verify)
1924                 final(pack_name, curr_pack,
1925                       index_name, curr_index,
1926                       rev_index_name, curr_rev_index,
1927                       keep_msg, promisor_msg,
1928                       pack_hash);
1929         else
1930                 close(input_fd);
1931
1932         if (do_fsck_object && fsck_finish(&fsck_options))
1933                 die(_("fsck error in pack objects"));
1934
1935         free(objects);
1936         strbuf_release(&index_name_buf);
1937         strbuf_release(&rev_index_name_buf);
1938         if (pack_name == NULL)
1939                 free((void *) curr_pack);
1940         if (index_name == NULL)
1941                 free((void *) curr_index);
1942         if (rev_index_name == NULL)
1943                 free((void *) curr_rev_index);
1944
1945         /*
1946          * Let the caller know this pack is not self contained
1947          */
1948         if (check_self_contained_and_connected && foreign_nr)
1949                 return 1;
1950
1951         return 0;
1952 }