builtin-fetch-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include "commit.h"
   5 #include "tag.h"
   6 #include "exec_cmd.h"
   7 #include "pack.h"
   8 #include "sideband.h"
   9 #include "fetch-pack.h"
  10 #include "remote.h"
  11 #include "run-command.h"
  12
  13 static int transfer_unpack_limit = -1;
  14 static int fetch_unpack_limit = -1;
  15 static int unpack_limit = 100;
  16 static struct fetch_pack_args args = {
  17         /* .uploadpack = */ "git-upload-pack",
  18 };
  19
  20 static const char fetch_pack_usage[] =
  21 "git-fetch-pack [--all] [--quiet|-q] [--keep|-k] [--thin] [--upload-pack=<git-upload-pack>] [--depth=<n>] [--no-progress] [-v] [<host>:]<directory> [<refs>...]";
  22
  23 #define COMPLETE        (1U << 0)
  24 #define COMMON          (1U << 1)
  25 #define COMMON_REF      (1U << 2)
  26 #define SEEN            (1U << 3)
  27 #define POPPED          (1U << 4)
  28
  29 /*
  30  * After sending this many "have"s if we do not get any new ACK , we
  31  * give up traversing our history.
  32  */
  33 #define MAX_IN_VAIN 256
  34
  35 static struct commit_list *rev_list;
  36 static int non_common_revs, multi_ack, use_sideband;
  37
  38 static void rev_list_push(struct commit *commit, int mark)
  39 {
  40         if (!(commit->object.flags & mark)) {
  41                 commit->object.flags |= mark;
  42
  43                 if (!(commit->object.parsed))
  44                         parse_commit(commit);
  45
  46                 insert_by_date(commit, &rev_list);
  47
  48                 if (!(commit->object.flags & COMMON))
  49                         non_common_revs++;
  50         }
  51 }
  52
  53 static int rev_list_insert_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
  54 {
  55         struct object *o = deref_tag(parse_object(sha1), path, 0);
  56
  57         if (o && o->type == OBJ_COMMIT)
  58                 rev_list_push((struct commit *)o, SEEN);
  59
  60         return 0;
  61 }
  62
  63 /*
  64    This function marks a rev and its ancestors as common.
  65    In some cases, it is desirable to mark only the ancestors (for example
  66    when only the server does not yet know that they are common).
  67 */
  68
  69 static void mark_common(struct commit *commit,
  70                 int ancestors_only, int dont_parse)
  71 {
  72         if (commit != NULL && !(commit->object.flags & COMMON)) {
  73                 struct object *o = (struct object *)commit;
  74
  75                 if (!ancestors_only)
  76                         o->flags |= COMMON;
  77
  78                 if (!(o->flags & SEEN))
  79                         rev_list_push(commit, SEEN);
  80                 else {
  81                         struct commit_list *parents;
  82
  83                         if (!ancestors_only && !(o->flags & POPPED))
  84                                 non_common_revs--;
  85                         if (!o->parsed && !dont_parse)
  86                                 parse_commit(commit);
  87
  88                         for (parents = commit->parents;
  89                                         parents;
  90                                         parents = parents->next)
  91                                 mark_common(parents->item, 0, dont_parse);
  92                 }
  93         }
  94 }
  95
  96 /*
  97   Get the next rev to send, ignoring the common.
  98 */
  99
 100 static const unsigned char* get_rev(void)
 101 {
 102         struct commit *commit = NULL;
 103
 104         while (commit == NULL) {
 105                 unsigned int mark;
 106                 struct commit_list* parents;
 107
 108                 if (rev_list == NULL || non_common_revs == 0)
 109                         return NULL;
 110
 111                 commit = rev_list->item;
 112                 if (!(commit->object.parsed))
 113                         parse_commit(commit);
 114                 commit->object.flags |= POPPED;
 115                 if (!(commit->object.flags & COMMON))
 116                         non_common_revs--;
 117
 118                 parents = commit->parents;
 119
 120                 if (commit->object.flags & COMMON) {
 121                         /* do not send "have", and ignore ancestors */
 122                         commit = NULL;
 123                         mark = COMMON | SEEN;
 124                 } else if (commit->object.flags & COMMON_REF)
 125                         /* send "have", and ignore ancestors */
 126                         mark = COMMON | SEEN;
 127                 else
 128                         /* send "have", also for its ancestors */
 129                         mark = SEEN;
 130
 131                 while (parents) {
 132                         if (!(parents->item->object.flags & SEEN))
 133                                 rev_list_push(parents->item, mark);
 134                         if (mark & COMMON)
 135                                 mark_common(parents->item, 1, 0);
 136                         parents = parents->next;
 137                 }
 138
 139                 rev_list = rev_list->next;
 140         }
 141
 142         return commit->object.sha1;
 143 }
 144
 145 static int find_common(int fd[2], unsigned char *result_sha1,
 146                        struct ref *refs)
 147 {
 148         int fetching;
 149         int count = 0, flushes = 0, retval;
 150         const unsigned char *sha1;
 151         unsigned in_vain = 0;
 152         int got_continue = 0;
 153
 154         for_each_ref(rev_list_insert_ref, NULL);
 155
 156         fetching = 0;
 157         for ( ; refs ; refs = refs->next) {
 158                 unsigned char *remote = refs->old_sha1;
 159                 struct object *o;
 160
 161                 /*
 162                  * If that object is complete (i.e. it is an ancestor of a
 163                  * local ref), we tell them we have it but do not have to
 164                  * tell them about its ancestors, which they already know
 165                  * about.
 166                  *
 167                  * We use lookup_object here because we are only
 168                  * interested in the case we *know* the object is
 169                  * reachable and we have already scanned it.
 170                  */
 171                 if (((o = lookup_object(remote)) != NULL) &&
 172                                 (o->flags & COMPLETE)) {
 173                         continue;
 174                 }
 175
 176                 if (!fetching)
 177                         packet_write(fd[1], "want %s%s%s%s%s%s%s\n",
 178                                      sha1_to_hex(remote),
 179                                      (multi_ack ? " multi_ack" : ""),
 180                                      (use_sideband == 2 ? " side-band-64k" : ""),
 181                                      (use_sideband == 1 ? " side-band" : ""),
 182                                      (args.use_thin_pack ? " thin-pack" : ""),
 183                                      (args.no_progress ? " no-progress" : ""),
 184                                      " ofs-delta");
 185                 else
 186                         packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
 187                 fetching++;
 188         }
 189         if (is_repository_shallow())
 190                 write_shallow_commits(fd[1], 1);
 191         if (args.depth > 0)
 192                 packet_write(fd[1], "deepen %d", args.depth);
 193         packet_flush(fd[1]);
 194         if (!fetching)
 195                 return 1;
 196
 197         if (args.depth > 0) {
 198                 char line[1024];
 199                 unsigned char sha1[20];
 200                 int len;
 201
 202                 while ((len = packet_read_line(fd[0], line, sizeof(line)))) {
 203                         if (!prefixcmp(line, "shallow ")) {
 204                                 if (get_sha1_hex(line + 8, sha1))
 205                                         die("invalid shallow line: %s", line);
 206                                 register_shallow(sha1);
 207                                 continue;
 208                         }
 209                         if (!prefixcmp(line, "unshallow ")) {
 210                                 if (get_sha1_hex(line + 10, sha1))
 211                                         die("invalid unshallow line: %s", line);
 212                                 if (!lookup_object(sha1))
 213                                         die("object not found: %s", line);
 214                                 /* make sure that it is parsed as shallow */
 215                                 parse_object(sha1);
 216                                 if (unregister_shallow(sha1))
 217                                         die("no shallow found: %s", line);
 218                                 continue;
 219                         }
 220                         die("expected shallow/unshallow, got %s", line);
 221                 }
 222         }
 223
 224         flushes = 0;
 225         retval = -1;
 226         while ((sha1 = get_rev())) {
 227                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
 228                 if (args.verbose)
 229                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 230                 in_vain++;
 231                 if (!(31 & ++count)) {
 232                         int ack;
 233
 234                         packet_flush(fd[1]);
 235                         flushes++;
 236
 237                         /*
 238                          * We keep one window "ahead" of the other side, and
 239                          * will wait for an ACK only on the next one
 240                          */
 241                         if (count == 32)
 242                                 continue;
 243
 244                         do {
 245                                 ack = get_ack(fd[0], result_sha1);
 246                                 if (args.verbose && ack)
 247                                         fprintf(stderr, "got ack %d %s\n", ack,
 248                                                         sha1_to_hex(result_sha1));
 249                                 if (ack == 1) {
 250                                         flushes = 0;
 251                                         multi_ack = 0;
 252                                         retval = 0;
 253                                         goto done;
 254                                 } else if (ack == 2) {
 255                                         struct commit *commit =
 256                                                 lookup_commit(result_sha1);
 257                                         mark_common(commit, 0, 1);
 258                                         retval = 0;
 259                                         in_vain = 0;
 260                                         got_continue = 1;
 261                                 }
 262                         } while (ack);
 263                         flushes--;
 264                         if (got_continue && MAX_IN_VAIN < in_vain) {
 265                                 if (args.verbose)
 266                                         fprintf(stderr, "giving up\n");
 267                                 break; /* give up */
 268                         }
 269                 }
 270         }
 271 done:
 272         packet_write(fd[1], "done\n");
 273         if (args.verbose)
 274                 fprintf(stderr, "done\n");
 275         if (retval != 0) {
 276                 multi_ack = 0;
 277                 flushes++;
 278         }
 279         while (flushes || multi_ack) {
 280                 int ack = get_ack(fd[0], result_sha1);
 281                 if (ack) {
 282                         if (args.verbose)
 283                                 fprintf(stderr, "got ack (%d) %s\n", ack,
 284                                         sha1_to_hex(result_sha1));
 285                         if (ack == 1)
 286                                 return 0;
 287                         multi_ack = 1;
 288                         continue;
 289                 }
 290                 flushes--;
 291         }
 292         return retval;
 293 }
 294
 295 static struct commit_list *complete;
 296
 297 static int mark_complete(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 298 {
 299         struct object *o = parse_object(sha1);
 300
 301         while (o && o->type == OBJ_TAG) {
 302                 struct tag *t = (struct tag *) o;
 303                 if (!t->tagged)
 304                         break; /* broken repository */
 305                 o->flags |= COMPLETE;
 306                 o = parse_object(t->tagged->sha1);
 307         }
 308         if (o && o->type == OBJ_COMMIT) {
 309                 struct commit *commit = (struct commit *)o;
 310                 commit->object.flags |= COMPLETE;
 311                 insert_by_date(commit, &complete);
 312         }
 313         return 0;
 314 }
 315
 316 static void mark_recent_complete_commits(unsigned long cutoff)
 317 {
 318         while (complete && cutoff <= complete->item->date) {
 319                 if (args.verbose)
 320                         fprintf(stderr, "Marking %s as complete\n",
 321                                 sha1_to_hex(complete->item->object.sha1));
 322                 pop_most_recent_commit(&complete, COMPLETE);
 323         }
 324 }
 325
 326 static void filter_refs(struct ref **refs, int nr_match, char **match)
 327 {
 328         struct ref **return_refs;
 329         struct ref *newlist = NULL;
 330         struct ref **newtail = &newlist;
 331         struct ref *ref, *next;
 332         struct ref *fastarray[32];
 333
 334         if (nr_match && !args.fetch_all) {
 335                 if (ARRAY_SIZE(fastarray) < nr_match)
 336                         return_refs = xcalloc(nr_match, sizeof(struct ref *));
 337                 else {
 338                         return_refs = fastarray;
 339                         memset(return_refs, 0, sizeof(struct ref *) * nr_match);
 340                 }
 341         }
 342         else
 343                 return_refs = NULL;
 344
 345         for (ref = *refs; ref; ref = next) {
 346                 next = ref->next;
 347                 if (!memcmp(ref->name, "refs/", 5) &&
 348                     check_ref_format(ref->name + 5))
 349                         ; /* trash */
 350                 else if (args.fetch_all &&
 351                          (!args.depth || prefixcmp(ref->name, "refs/tags/") )) {
 352                         *newtail = ref;
 353                         ref->next = NULL;
 354                         newtail = &ref->next;
 355                         continue;
 356                 }
 357                 else {
 358                         int order = path_match(ref->name, nr_match, match);
 359                         if (order) {
 360                                 return_refs[order-1] = ref;
 361                                 continue; /* we will link it later */
 362                         }
 363                 }
 364                 free(ref);
 365         }
 366
 367         if (!args.fetch_all) {
 368                 int i;
 369                 for (i = 0; i < nr_match; i++) {
 370                         ref = return_refs[i];
 371                         if (ref) {
 372                                 *newtail = ref;
 373                                 ref->next = NULL;
 374                                 newtail = &ref->next;
 375                         }
 376                 }
 377                 if (return_refs != fastarray)
 378                         free(return_refs);
 379         }
 380         *refs = newlist;
 381 }
 382
 383 static int everything_local(struct ref **refs, int nr_match, char **match)
 384 {
 385         struct ref *ref;
 386         int retval;
 387         unsigned long cutoff = 0;
 388
 389         track_object_refs = 0;
 390         save_commit_buffer = 0;
 391
 392         for (ref = *refs; ref; ref = ref->next) {
 393                 struct object *o;
 394
 395                 o = parse_object(ref->old_sha1);
 396                 if (!o)
 397                         continue;
 398
 399                 /* We already have it -- which may mean that we were
 400                  * in sync with the other side at some time after
 401                  * that (it is OK if we guess wrong here).
 402                  */
 403                 if (o->type == OBJ_COMMIT) {
 404                         struct commit *commit = (struct commit *)o;
 405                         if (!cutoff || cutoff < commit->date)
 406                                 cutoff = commit->date;
 407                 }
 408         }
 409
 410         if (!args.depth) {
 411                 for_each_ref(mark_complete, NULL);
 412                 if (cutoff)
 413                         mark_recent_complete_commits(cutoff);
 414         }
 415
 416         /*
 417          * Mark all complete remote refs as common refs.
 418          * Don't mark them common yet; the server has to be told so first.
 419          */
 420         for (ref = *refs; ref; ref = ref->next) {
 421                 struct object *o = deref_tag(lookup_object(ref->old_sha1),
 422                                              NULL, 0);
 423
 424                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 425                         continue;
 426
 427                 if (!(o->flags & SEEN)) {
 428                         rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 429
 430                         mark_common((struct commit *)o, 1, 1);
 431                 }
 432         }
 433
 434         filter_refs(refs, nr_match, match);
 435
 436         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 437                 const unsigned char *remote = ref->old_sha1;
 438                 unsigned char local[20];
 439                 struct object *o;
 440
 441                 o = lookup_object(remote);
 442                 if (!o || !(o->flags & COMPLETE)) {
 443                         retval = 0;
 444                         if (!args.verbose)
 445                                 continue;
 446                         fprintf(stderr,
 447                                 "want %s (%s)\n", sha1_to_hex(remote),
 448                                 ref->name);
 449                         continue;
 450                 }
 451
 452                 hashcpy(ref->new_sha1, local);
 453                 if (!args.verbose)
 454                         continue;
 455                 fprintf(stderr,
 456                         "already have %s (%s)\n", sha1_to_hex(remote),
 457                         ref->name);
 458         }
 459         return retval;
 460 }
 461
 462 static int sideband_demux(int fd, void *data)
 463 {
 464         int *xd = data;
 465
 466         return recv_sideband("fetch-pack", xd[0], fd, 2);
 467 }
 468
 469 static int get_pack(int xd[2], char **pack_lockfile)
 470 {
 471         struct async demux;
 472         const char *argv[20];
 473         char keep_arg[256];
 474         char hdr_arg[256];
 475         const char **av;
 476         int do_keep = args.keep_pack;
 477         struct child_process cmd;
 478
 479         memset(&demux, 0, sizeof(demux));
 480         if (use_sideband) {
 481                 /* xd[] is talking with upload-pack; subprocess reads from
 482                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 483                  * through demux->out.
 484                  */
 485                 demux.proc = sideband_demux;
 486                 demux.data = xd;
 487                 if (start_async(&demux))
 488                         die("fetch-pack: unable to fork off sideband"
 489                             " demultiplexer");
 490         }
 491         else
 492                 demux.out = xd[0];
 493
 494         memset(&cmd, 0, sizeof(cmd));
 495         cmd.argv = argv;
 496         av = argv;
 497         *hdr_arg = 0;
 498         if (!args.keep_pack && unpack_limit) {
 499                 struct pack_header header;
 500
 501                 if (read_pack_header(demux.out, &header))
 502                         die("protocol error: bad pack header");
 503                 snprintf(hdr_arg, sizeof(hdr_arg), "--pack_header=%u,%u",
 504                          ntohl(header.hdr_version), ntohl(header.hdr_entries));
 505                 if (ntohl(header.hdr_entries) < unpack_limit)
 506                         do_keep = 0;
 507                 else
 508                         do_keep = 1;
 509         }
 510
 511         if (do_keep) {
 512                 if (pack_lockfile)
 513                         cmd.out = -1;
 514                 *av++ = "index-pack";
 515                 *av++ = "--stdin";
 516                 if (!args.quiet && !args.no_progress)
 517                         *av++ = "-v";
 518                 if (args.use_thin_pack)
 519                         *av++ = "--fix-thin";
 520                 if (args.lock_pack || unpack_limit) {
 521                         int s = sprintf(keep_arg,
 522                                         "--keep=fetch-pack %d on ", getpid());
 523                         if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 524                                 strcpy(keep_arg + s, "localhost");
 525                         *av++ = keep_arg;
 526                 }
 527         }
 528         else {
 529                 *av++ = "unpack-objects";
 530                 if (args.quiet)
 531                         *av++ = "-q";
 532         }
 533         if (*hdr_arg)
 534                 *av++ = hdr_arg;
 535         *av++ = NULL;
 536
 537         cmd.in = demux.out;
 538         cmd.git_cmd = 1;
 539         if (start_command(&cmd))
 540                 die("fetch-pack: unable to fork off %s", argv[0]);
 541         if (do_keep && pack_lockfile) {
 542                 *pack_lockfile = index_pack_lockfile(cmd.out);
 543                 close(cmd.out);
 544         }
 545
 546         if (finish_command(&cmd))
 547                 die("%s failed", argv[0]);
 548         if (use_sideband && finish_async(&demux))
 549                 die("error in sideband demultiplexer");
 550         return 0;
 551 }
 552
 553 static struct ref *do_fetch_pack(int fd[2],
 554                 const struct ref *orig_ref,
 555                 int nr_match,
 556                 char **match,
 557                 char **pack_lockfile)
 558 {
 559         struct ref *ref = copy_ref_list(orig_ref);
 560         unsigned char sha1[20];
 561
 562         if (is_repository_shallow() && !server_supports("shallow"))
 563                 die("Server does not support shallow clients");
 564         if (server_supports("multi_ack")) {
 565                 if (args.verbose)
 566                         fprintf(stderr, "Server supports multi_ack\n");
 567                 multi_ack = 1;
 568         }
 569         if (server_supports("side-band-64k")) {
 570                 if (args.verbose)
 571                         fprintf(stderr, "Server supports side-band-64k\n");
 572                 use_sideband = 2;
 573         }
 574         else if (server_supports("side-band")) {
 575                 if (args.verbose)
 576                         fprintf(stderr, "Server supports side-band\n");
 577                 use_sideband = 1;
 578         }
 579         if (everything_local(&ref, nr_match, match)) {
 580                 packet_flush(fd[1]);
 581                 goto all_done;
 582         }
 583         if (find_common(fd, sha1, ref) < 0)
 584                 if (!args.keep_pack)
 585                         /* When cloning, it is not unusual to have
 586                          * no common commit.
 587                          */
 588                         fprintf(stderr, "warning: no common commits\n");
 589
 590         if (get_pack(fd, pack_lockfile))
 591                 die("git-fetch-pack: fetch failed.");
 592
 593  all_done:
 594         return ref;
 595 }
 596
 597 static int remove_duplicates(int nr_heads, char **heads)
 598 {
 599         int src, dst;
 600
 601         for (src = dst = 0; src < nr_heads; src++) {
 602                 /* If heads[src] is different from any of
 603                  * heads[0..dst], push it in.
 604                  */
 605                 int i;
 606                 for (i = 0; i < dst; i++) {
 607                         if (!strcmp(heads[i], heads[src]))
 608                                 break;
 609                 }
 610                 if (i < dst)
 611                         continue;
 612                 if (src != dst)
 613                         heads[dst] = heads[src];
 614                 dst++;
 615         }
 616         return dst;
 617 }
 618
 619 static int fetch_pack_config(const char *var, const char *value)
 620 {
 621         if (strcmp(var, "fetch.unpacklimit") == 0) {
 622                 fetch_unpack_limit = git_config_int(var, value);
 623                 return 0;
 624         }
 625
 626         if (strcmp(var, "transfer.unpacklimit") == 0) {
 627                 transfer_unpack_limit = git_config_int(var, value);
 628                 return 0;
 629         }
 630
 631         return git_default_config(var, value);
 632 }
 633
 634 static struct lock_file lock;
 635
 636 static void fetch_pack_setup(void)
 637 {
 638         static int did_setup;
 639         if (did_setup)
 640                 return;
 641         git_config(fetch_pack_config);
 642         if (0 <= transfer_unpack_limit)
 643                 unpack_limit = transfer_unpack_limit;
 644         else if (0 <= fetch_unpack_limit)
 645                 unpack_limit = fetch_unpack_limit;
 646         did_setup = 1;
 647 }
 648
 649 int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 650 {
 651         int i, ret, nr_heads;
 652         struct ref *ref = NULL;
 653         char *dest = NULL, **heads;
 654         int fd[2];
 655         struct child_process *conn;
 656
 657         nr_heads = 0;
 658         heads = NULL;
 659         for (i = 1; i < argc; i++) {
 660                 const char *arg = argv[i];
 661
 662                 if (*arg == '-') {
 663                         if (!prefixcmp(arg, "--upload-pack=")) {
 664                                 args.uploadpack = arg + 14;
 665                                 continue;
 666                         }
 667                         if (!prefixcmp(arg, "--exec=")) {
 668                                 args.uploadpack = arg + 7;
 669                                 continue;
 670                         }
 671                         if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
 672                                 args.quiet = 1;
 673                                 continue;
 674                         }
 675                         if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
 676                                 args.lock_pack = args.keep_pack;
 677                                 args.keep_pack = 1;
 678                                 continue;
 679                         }
 680                         if (!strcmp("--thin", arg)) {
 681                                 args.use_thin_pack = 1;
 682                                 continue;
 683                         }
 684                         if (!strcmp("--all", arg)) {
 685                                 args.fetch_all = 1;
 686                                 continue;
 687                         }
 688                         if (!strcmp("-v", arg)) {
 689                                 args.verbose = 1;
 690                                 continue;
 691                         }
 692                         if (!prefixcmp(arg, "--depth=")) {
 693                                 args.depth = strtol(arg + 8, NULL, 0);
 694                                 continue;
 695                         }
 696                         if (!strcmp("--no-progress", arg)) {
 697                                 args.no_progress = 1;
 698                                 continue;
 699                         }
 700                         usage(fetch_pack_usage);
 701                 }
 702                 dest = (char *)arg;
 703                 heads = (char **)(argv + i + 1);
 704                 nr_heads = argc - i - 1;
 705                 break;
 706         }
 707         if (!dest)
 708                 usage(fetch_pack_usage);
 709
 710         conn = git_connect(fd, (char *)dest, args.uploadpack,
 711                            args.verbose ? CONNECT_VERBOSE : 0);
 712         if (conn) {
 713                 get_remote_heads(fd[0], &ref, 0, NULL, 0);
 714
 715                 ref = fetch_pack(&args, fd, conn, ref, dest, nr_heads, heads, NULL);
 716                 close(fd[0]);
 717                 close(fd[1]);
 718                 if (finish_connect(conn))
 719                         ref = NULL;
 720         } else {
 721                 ref = NULL;
 722         }
 723         ret = !ref;
 724
 725         if (!ret && nr_heads) {
 726                 /* If the heads to pull were given, we should have
 727                  * consumed all of them by matching the remote.
 728                  * Otherwise, 'git-fetch remote no-such-ref' would
 729                  * silently succeed without issuing an error.
 730                  */
 731                 for (i = 0; i < nr_heads; i++)
 732                         if (heads[i] && heads[i][0]) {
 733                                 error("no such remote ref %s", heads[i]);
 734                                 ret = 1;
 735                         }
 736         }
 737         while (ref) {
 738                 printf("%s %s\n",
 739                        sha1_to_hex(ref->old_sha1), ref->name);
 740                 ref = ref->next;
 741         }
 742
 743         return ret;
 744 }
 745
 746 struct ref *fetch_pack(struct fetch_pack_args *my_args,
 747                        int fd[], struct child_process *conn,
 748                        const struct ref *ref,
 749                 const char *dest,
 750                 int nr_heads,
 751                 char **heads,
 752                 char **pack_lockfile)
 753 {
 754         struct stat st;
 755         struct ref *ref_cpy;
 756
 757         fetch_pack_setup();
 758         memcpy(&args, my_args, sizeof(args));
 759         if (args.depth > 0) {
 760                 if (stat(git_path("shallow"), &st))
 761                         st.st_mtime = 0;
 762         }
 763
 764         if (heads && nr_heads)
 765                 nr_heads = remove_duplicates(nr_heads, heads);
 766         if (!ref) {
 767                 packet_flush(fd[1]);
 768                 die("no matching remote head");
 769         }
 770         ref_cpy = do_fetch_pack(fd, ref, nr_heads, heads, pack_lockfile);
 771
 772         if (args.depth > 0) {
 773                 struct cache_time mtime;
 774                 char *shallow = git_path("shallow");
 775                 int fd;
 776
 777                 mtime.sec = st.st_mtime;
 778 #ifdef USE_NSEC
 779                 mtime.usec = st.st_mtim.usec;
 780 #endif
 781                 if (stat(shallow, &st)) {
 782                         if (mtime.sec)
 783                                 die("shallow file was removed during fetch");
 784                 } else if (st.st_mtime != mtime.sec
 785 #ifdef USE_NSEC
 786                                 || st.st_mtim.usec != mtime.usec
 787 #endif
 788                           )
 789                         die("shallow file was changed during fetch");
 790
 791                 fd = hold_lock_file_for_update(&lock, shallow, 1);
 792                 if (!write_shallow_commits(fd, 0)) {
 793                         unlink(shallow);
 794                         rollback_lock_file(&lock);
 795                 } else {
 796                         commit_lock_file(&lock);
 797                 }
 798         }
 799
 800         return ref_cpy;
 801 }