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 "run-command.h"
  11
  12 static int transfer_unpack_limit = -1;
  13 static int fetch_unpack_limit = -1;
  14 static int unpack_limit = 100;
  15 static struct fetch_pack_args args = {
  16         /* .uploadpack = */ "git-upload-pack",
  17 };
  18
  19 static const char fetch_pack_usage[] =
  20 "git-fetch-pack [--all] [--quiet|-q] [--keep|-k] [--thin] [--upload-pack=<git-upload-pack>] [--depth=<n>] [--no-progress] [-v] [<host>:]<directory> [<refs>...]";
  21
  22 #define COMPLETE        (1U << 0)
  23 #define COMMON          (1U << 1)
  24 #define COMMON_REF      (1U << 2)
  25 #define SEEN            (1U << 3)
  26 #define POPPED          (1U << 4)
  27
  28 /*
  29  * After sending this many "have"s if we do not get any new ACK , we
  30  * give up traversing our history.
  31  */
  32 #define MAX_IN_VAIN 256
  33
  34 static struct commit_list *rev_list;
  35 static int non_common_revs, multi_ack, use_thin_pack, use_sideband;
  36
  37 static void rev_list_push(struct commit *commit, int mark)
  38 {
  39         if (!(commit->object.flags & mark)) {
  40                 commit->object.flags |= mark;
  41
  42                 if (!(commit->object.parsed))
  43                         parse_commit(commit);
  44
  45                 insert_by_date(commit, &rev_list);
  46
  47                 if (!(commit->object.flags & COMMON))
  48                         non_common_revs++;
  49         }
  50 }
  51
  52 static int rev_list_insert_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
  53 {
  54         struct object *o = deref_tag(parse_object(sha1), path, 0);
  55
  56         if (o && o->type == OBJ_COMMIT)
  57                 rev_list_push((struct commit *)o, SEEN);
  58
  59         return 0;
  60 }
  61
  62 /*
  63    This function marks a rev and its ancestors as common.
  64    In some cases, it is desirable to mark only the ancestors (for example
  65    when only the server does not yet know that they are common).
  66 */
  67
  68 static void mark_common(struct commit *commit,
  69                 int ancestors_only, int dont_parse)
  70 {
  71         if (commit != NULL && !(commit->object.flags & COMMON)) {
  72                 struct object *o = (struct object *)commit;
  73
  74                 if (!ancestors_only)
  75                         o->flags |= COMMON;
  76
  77                 if (!(o->flags & SEEN))
  78                         rev_list_push(commit, SEEN);
  79                 else {
  80                         struct commit_list *parents;
  81
  82                         if (!ancestors_only && !(o->flags & POPPED))
  83                                 non_common_revs--;
  84                         if (!o->parsed && !dont_parse)
  85                                 parse_commit(commit);
  86
  87                         for (parents = commit->parents;
  88                                         parents;
  89                                         parents = parents->next)
  90                                 mark_common(parents->item, 0, dont_parse);
  91                 }
  92         }
  93 }
  94
  95 /*
  96   Get the next rev to send, ignoring the common.
  97 */
  98
  99 static const unsigned char* get_rev(void)
 100 {
 101         struct commit *commit = NULL;
 102
 103         while (commit == NULL) {
 104                 unsigned int mark;
 105                 struct commit_list* parents;
 106
 107                 if (rev_list == NULL || non_common_revs == 0)
 108                         return NULL;
 109
 110                 commit = rev_list->item;
 111                 if (!(commit->object.parsed))
 112                         parse_commit(commit);
 113                 commit->object.flags |= POPPED;
 114                 if (!(commit->object.flags & COMMON))
 115                         non_common_revs--;
 116
 117                 parents = commit->parents;
 118
 119                 if (commit->object.flags & COMMON) {
 120                         /* do not send "have", and ignore ancestors */
 121                         commit = NULL;
 122                         mark = COMMON | SEEN;
 123                 } else if (commit->object.flags & COMMON_REF)
 124                         /* send "have", and ignore ancestors */
 125                         mark = COMMON | SEEN;
 126                 else
 127                         /* send "have", also for its ancestors */
 128                         mark = SEEN;
 129
 130                 while (parents) {
 131                         if (!(parents->item->object.flags & SEEN))
 132                                 rev_list_push(parents->item, mark);
 133                         if (mark & COMMON)
 134                                 mark_common(parents->item, 1, 0);
 135                         parents = parents->next;
 136                 }
 137
 138                 rev_list = rev_list->next;
 139         }
 140
 141         return commit->object.sha1;
 142 }
 143
 144 static int find_common(int fd[2], unsigned char *result_sha1,
 145                        struct ref *refs)
 146 {
 147         int fetching;
 148         int count = 0, flushes = 0, retval;
 149         const unsigned char *sha1;
 150         unsigned in_vain = 0;
 151         int got_continue = 0;
 152
 153         for_each_ref(rev_list_insert_ref, NULL);
 154
 155         fetching = 0;
 156         for ( ; refs ; refs = refs->next) {
 157                 unsigned char *remote = refs->old_sha1;
 158                 struct object *o;
 159
 160                 /*
 161                  * If that object is complete (i.e. it is an ancestor of a
 162                  * local ref), we tell them we have it but do not have to
 163                  * tell them about its ancestors, which they already know
 164                  * about.
 165                  *
 166                  * We use lookup_object here because we are only
 167                  * interested in the case we *know* the object is
 168                  * reachable and we have already scanned it.
 169                  */
 170                 if (((o = lookup_object(remote)) != NULL) &&
 171                                 (o->flags & COMPLETE)) {
 172                         continue;
 173                 }
 174
 175                 if (!fetching)
 176                         packet_write(fd[1], "want %s%s%s%s%s%s%s\n",
 177                                      sha1_to_hex(remote),
 178                                      (multi_ack ? " multi_ack" : ""),
 179                                      (use_sideband == 2 ? " side-band-64k" : ""),
 180                                      (use_sideband == 1 ? " side-band" : ""),
 181                                      (use_thin_pack ? " thin-pack" : ""),
 182                                      (args.no_progress ? " no-progress" : ""),
 183                                      " ofs-delta");
 184                 else
 185                         packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
 186                 fetching++;
 187         }
 188         if (is_repository_shallow())
 189                 write_shallow_commits(fd[1], 1);
 190         if (args.depth > 0)
 191                 packet_write(fd[1], "deepen %d", args.depth);
 192         packet_flush(fd[1]);
 193         if (!fetching)
 194                 return 1;
 195
 196         if (args.depth > 0) {
 197                 char line[1024];
 198                 unsigned char sha1[20];
 199                 int len;
 200
 201                 while ((len = packet_read_line(fd[0], line, sizeof(line)))) {
 202                         if (!prefixcmp(line, "shallow ")) {
 203                                 if (get_sha1_hex(line + 8, sha1))
 204                                         die("invalid shallow line: %s", line);
 205                                 register_shallow(sha1);
 206                                 continue;
 207                         }
 208                         if (!prefixcmp(line, "unshallow ")) {
 209                                 if (get_sha1_hex(line + 10, sha1))
 210                                         die("invalid unshallow line: %s", line);
 211                                 if (!lookup_object(sha1))
 212                                         die("object not found: %s", line);
 213                                 /* make sure that it is parsed as shallow */
 214                                 parse_object(sha1);
 215                                 if (unregister_shallow(sha1))
 216                                         die("no shallow found: %s", line);
 217                                 continue;
 218                         }
 219                         die("expected shallow/unshallow, got %s", line);
 220                 }
 221         }
 222
 223         flushes = 0;
 224         retval = -1;
 225         while ((sha1 = get_rev())) {
 226                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
 227                 if (args.verbose)
 228                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 229                 in_vain++;
 230                 if (!(31 & ++count)) {
 231                         int ack;
 232
 233                         packet_flush(fd[1]);
 234                         flushes++;
 235
 236                         /*
 237                          * We keep one window "ahead" of the other side, and
 238                          * will wait for an ACK only on the next one
 239                          */
 240                         if (count == 32)
 241                                 continue;
 242
 243                         do {
 244                                 ack = get_ack(fd[0], result_sha1);
 245                                 if (args.verbose && ack)
 246                                         fprintf(stderr, "got ack %d %s\n", ack,
 247                                                         sha1_to_hex(result_sha1));
 248                                 if (ack == 1) {
 249                                         flushes = 0;
 250                                         multi_ack = 0;
 251                                         retval = 0;
 252                                         goto done;
 253                                 } else if (ack == 2) {
 254                                         struct commit *commit =
 255                                                 lookup_commit(result_sha1);
 256                                         mark_common(commit, 0, 1);
 257                                         retval = 0;
 258                                         in_vain = 0;
 259                                         got_continue = 1;
 260                                 }
 261                         } while (ack);
 262                         flushes--;
 263                         if (got_continue && MAX_IN_VAIN < in_vain) {
 264                                 if (args.verbose)
 265                                         fprintf(stderr, "giving up\n");
 266                                 break; /* give up */
 267                         }
 268                 }
 269         }
 270 done:
 271         packet_write(fd[1], "done\n");
 272         if (args.verbose)
 273                 fprintf(stderr, "done\n");
 274         if (retval != 0) {
 275                 multi_ack = 0;
 276                 flushes++;
 277         }
 278         while (flushes || multi_ack) {
 279                 int ack = get_ack(fd[0], result_sha1);
 280                 if (ack) {
 281                         if (args.verbose)
 282                                 fprintf(stderr, "got ack (%d) %s\n", ack,
 283                                         sha1_to_hex(result_sha1));
 284                         if (ack == 1)
 285                                 return 0;
 286                         multi_ack = 1;
 287                         continue;
 288                 }
 289                 flushes--;
 290         }
 291         return retval;
 292 }
 293
 294 static struct commit_list *complete;
 295
 296 static int mark_complete(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 297 {
 298         struct object *o = parse_object(sha1);
 299
 300         while (o && o->type == OBJ_TAG) {
 301                 struct tag *t = (struct tag *) o;
 302                 if (!t->tagged)
 303                         break; /* broken repository */
 304                 o->flags |= COMPLETE;
 305                 o = parse_object(t->tagged->sha1);
 306         }
 307         if (o && o->type == OBJ_COMMIT) {
 308                 struct commit *commit = (struct commit *)o;
 309                 commit->object.flags |= COMPLETE;
 310                 insert_by_date(commit, &complete);
 311         }
 312         return 0;
 313 }
 314
 315 static void mark_recent_complete_commits(unsigned long cutoff)
 316 {
 317         while (complete && cutoff <= complete->item->date) {
 318                 if (args.verbose)
 319                         fprintf(stderr, "Marking %s as complete\n",
 320                                 sha1_to_hex(complete->item->object.sha1));
 321                 pop_most_recent_commit(&complete, COMPLETE);
 322         }
 323 }
 324
 325 static void filter_refs(struct ref **refs, int nr_match, char **match)
 326 {
 327         struct ref **return_refs;
 328         struct ref *newlist = NULL;
 329         struct ref **newtail = &newlist;
 330         struct ref *ref, *next;
 331         struct ref *fastarray[32];
 332
 333         if (nr_match && !args.fetch_all) {
 334                 if (ARRAY_SIZE(fastarray) < nr_match)
 335                         return_refs = xcalloc(nr_match, sizeof(struct ref *));
 336                 else {
 337                         return_refs = fastarray;
 338                         memset(return_refs, 0, sizeof(struct ref *) * nr_match);
 339                 }
 340         }
 341         else
 342                 return_refs = NULL;
 343
 344         for (ref = *refs; ref; ref = next) {
 345                 next = ref->next;
 346                 if (!memcmp(ref->name, "refs/", 5) &&
 347                     check_ref_format(ref->name + 5))
 348                         ; /* trash */
 349                 else if (args.fetch_all &&
 350                          (!args.depth || prefixcmp(ref->name, "refs/tags/") )) {
 351                         *newtail = ref;
 352                         ref->next = NULL;
 353                         newtail = &ref->next;
 354                         continue;
 355                 }
 356                 else {
 357                         int order = path_match(ref->name, nr_match, match);
 358                         if (order) {
 359                                 return_refs[order-1] = ref;
 360                                 continue; /* we will link it later */
 361                         }
 362                 }
 363                 free(ref);
 364         }
 365
 366         if (!args.fetch_all) {
 367                 int i;
 368                 for (i = 0; i < nr_match; i++) {
 369                         ref = return_refs[i];
 370                         if (ref) {
 371                                 *newtail = ref;
 372                                 ref->next = NULL;
 373                                 newtail = &ref->next;
 374                         }
 375                 }
 376                 if (return_refs != fastarray)
 377                         free(return_refs);
 378         }
 379         *refs = newlist;
 380 }
 381
 382 static int everything_local(struct ref **refs, int nr_match, char **match)
 383 {
 384         struct ref *ref;
 385         int retval;
 386         unsigned long cutoff = 0;
 387
 388         track_object_refs = 0;
 389         save_commit_buffer = 0;
 390
 391         for (ref = *refs; ref; ref = ref->next) {
 392                 struct object *o;
 393
 394                 o = parse_object(ref->old_sha1);
 395                 if (!o)
 396                         continue;
 397
 398                 /* We already have it -- which may mean that we were
 399                  * in sync with the other side at some time after
 400                  * that (it is OK if we guess wrong here).
 401                  */
 402                 if (o->type == OBJ_COMMIT) {
 403                         struct commit *commit = (struct commit *)o;
 404                         if (!cutoff || cutoff < commit->date)
 405                                 cutoff = commit->date;
 406                 }
 407         }
 408
 409         if (!args.depth) {
 410                 for_each_ref(mark_complete, NULL);
 411                 if (cutoff)
 412                         mark_recent_complete_commits(cutoff);
 413         }
 414
 415         /*
 416          * Mark all complete remote refs as common refs.
 417          * Don't mark them common yet; the server has to be told so first.
 418          */
 419         for (ref = *refs; ref; ref = ref->next) {
 420                 struct object *o = deref_tag(lookup_object(ref->old_sha1),
 421                                              NULL, 0);
 422
 423                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 424                         continue;
 425
 426                 if (!(o->flags & SEEN)) {
 427                         rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 428
 429                         mark_common((struct commit *)o, 1, 1);
 430                 }
 431         }
 432
 433         filter_refs(refs, nr_match, match);
 434
 435         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 436                 const unsigned char *remote = ref->old_sha1;
 437                 unsigned char local[20];
 438                 struct object *o;
 439
 440                 o = lookup_object(remote);
 441                 if (!o || !(o->flags & COMPLETE)) {
 442                         retval = 0;
 443                         if (!args.verbose)
 444                                 continue;
 445                         fprintf(stderr,
 446                                 "want %s (%s)\n", sha1_to_hex(remote),
 447                                 ref->name);
 448                         continue;
 449                 }
 450
 451                 hashcpy(ref->new_sha1, local);
 452                 if (!args.verbose)
 453                         continue;
 454                 fprintf(stderr,
 455                         "already have %s (%s)\n", sha1_to_hex(remote),
 456                         ref->name);
 457         }
 458         return retval;
 459 }
 460
 461 static int sideband_demux(int fd, void *data)
 462 {
 463         int *xd = data;
 464
 465         close(xd[1]);
 466         return recv_sideband("fetch-pack", xd[0], fd, 2);
 467 }
 468
 469 static void setup_sideband(int fd[2], int xd[2], struct async *demux)
 470 {
 471         if (!use_sideband) {
 472                 fd[0] = xd[0];
 473                 fd[1] = xd[1];
 474                 return;
 475         }
 476         /* xd[] is talking with upload-pack; subprocess reads from
 477          * xd[0], spits out band#2 to stderr, and feeds us band#1
 478          * through demux->out.
 479          */
 480         demux->proc = sideband_demux;
 481         demux->data = xd;
 482         if (start_async(demux))
 483                 die("fetch-pack: unable to fork off sideband demultiplexer");
 484         close(xd[0]);
 485         fd[0] = demux->out;
 486         fd[1] = xd[1];
 487 }
 488
 489 static int get_pack(int xd[2], char **pack_lockfile)
 490 {
 491         struct async demux;
 492         int fd[2];
 493         const char *argv[20];
 494         char keep_arg[256];
 495         char hdr_arg[256];
 496         const char **av;
 497         int do_keep = args.keep_pack;
 498         struct child_process cmd;
 499
 500         setup_sideband(fd, xd, &demux);
 501
 502         memset(&cmd, 0, sizeof(cmd));
 503         cmd.argv = argv;
 504         av = argv;
 505         *hdr_arg = 0;
 506         if (!args.keep_pack && unpack_limit) {
 507                 struct pack_header header;
 508
 509                 if (read_pack_header(fd[0], &header))
 510                         die("protocol error: bad pack header");
 511                 snprintf(hdr_arg, sizeof(hdr_arg), "--pack_header=%u,%u",
 512                          ntohl(header.hdr_version), ntohl(header.hdr_entries));
 513                 if (ntohl(header.hdr_entries) < unpack_limit)
 514                         do_keep = 0;
 515                 else
 516                         do_keep = 1;
 517         }
 518
 519         if (do_keep) {
 520                 if (pack_lockfile)
 521                         cmd.out = -1;
 522                 *av++ = "index-pack";
 523                 *av++ = "--stdin";
 524                 if (!args.quiet && !args.no_progress)
 525                         *av++ = "-v";
 526                 if (args.use_thin_pack)
 527                         *av++ = "--fix-thin";
 528                 if (args.lock_pack || unpack_limit) {
 529                         int s = sprintf(keep_arg,
 530                                         "--keep=fetch-pack %d on ", getpid());
 531                         if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 532                                 strcpy(keep_arg + s, "localhost");
 533                         *av++ = keep_arg;
 534                 }
 535         }
 536         else {
 537                 *av++ = "unpack-objects";
 538                 if (args.quiet)
 539                         *av++ = "-q";
 540         }
 541         if (*hdr_arg)
 542                 *av++ = hdr_arg;
 543         *av++ = NULL;
 544
 545         cmd.in = fd[0];
 546         cmd.git_cmd = 1;
 547         if (start_command(&cmd))
 548                 die("fetch-pack: unable to fork off %s", argv[0]);
 549         close(fd[1]);
 550         if (do_keep && pack_lockfile)
 551                 *pack_lockfile = index_pack_lockfile(cmd.out);
 552
 553         if (finish_command(&cmd))
 554                 die("%s failed", argv[0]);
 555         if (use_sideband && finish_async(&demux))
 556                 die("error in sideband demultiplexer");
 557         return 0;
 558 }
 559
 560 static struct ref *do_fetch_pack(int fd[2],
 561                 int nr_match,
 562                 char **match,
 563                 char **pack_lockfile)
 564 {
 565         struct ref *ref;
 566         unsigned char sha1[20];
 567
 568         get_remote_heads(fd[0], &ref, 0, NULL, 0);
 569         if (is_repository_shallow() && !server_supports("shallow"))
 570                 die("Server does not support shallow clients");
 571         if (server_supports("multi_ack")) {
 572                 if (args.verbose)
 573                         fprintf(stderr, "Server supports multi_ack\n");
 574                 multi_ack = 1;
 575         }
 576         if (server_supports("side-band-64k")) {
 577                 if (args.verbose)
 578                         fprintf(stderr, "Server supports side-band-64k\n");
 579                 use_sideband = 2;
 580         }
 581         else if (server_supports("side-band")) {
 582                 if (args.verbose)
 583                         fprintf(stderr, "Server supports side-band\n");
 584                 use_sideband = 1;
 585         }
 586         if (!ref) {
 587                 packet_flush(fd[1]);
 588                 die("no matching remote head");
 589         }
 590         if (everything_local(&ref, nr_match, match)) {
 591                 packet_flush(fd[1]);
 592                 goto all_done;
 593         }
 594         if (find_common(fd, sha1, ref) < 0)
 595                 if (!args.keep_pack)
 596                         /* When cloning, it is not unusual to have
 597                          * no common commit.
 598                          */
 599                         fprintf(stderr, "warning: no common commits\n");
 600
 601         if (get_pack(fd, pack_lockfile))
 602                 die("git-fetch-pack: fetch failed.");
 603
 604  all_done:
 605         return ref;
 606 }
 607
 608 static int remove_duplicates(int nr_heads, char **heads)
 609 {
 610         int src, dst;
 611
 612         for (src = dst = 0; src < nr_heads; src++) {
 613                 /* If heads[src] is different from any of
 614                  * heads[0..dst], push it in.
 615                  */
 616                 int i;
 617                 for (i = 0; i < dst; i++) {
 618                         if (!strcmp(heads[i], heads[src]))
 619                                 break;
 620                 }
 621                 if (i < dst)
 622                         continue;
 623                 if (src != dst)
 624                         heads[dst] = heads[src];
 625                 dst++;
 626         }
 627         return dst;
 628 }
 629
 630 static int fetch_pack_config(const char *var, const char *value)
 631 {
 632         if (strcmp(var, "fetch.unpacklimit") == 0) {
 633                 fetch_unpack_limit = git_config_int(var, value);
 634                 return 0;
 635         }
 636
 637         if (strcmp(var, "transfer.unpacklimit") == 0) {
 638                 transfer_unpack_limit = git_config_int(var, value);
 639                 return 0;
 640         }
 641
 642         return git_default_config(var, value);
 643 }
 644
 645 static struct lock_file lock;
 646
 647 static void fetch_pack_setup(void)
 648 {
 649         static int did_setup;
 650         if (did_setup)
 651                 return;
 652         git_config(fetch_pack_config);
 653         if (0 <= transfer_unpack_limit)
 654                 unpack_limit = transfer_unpack_limit;
 655         else if (0 <= fetch_unpack_limit)
 656                 unpack_limit = fetch_unpack_limit;
 657         did_setup = 1;
 658 }
 659
 660 int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 661 {
 662         int i, ret, nr_heads;
 663         struct ref *ref;
 664         char *dest = NULL, **heads;
 665
 666         nr_heads = 0;
 667         heads = NULL;
 668         for (i = 1; i < argc; i++) {
 669                 const char *arg = argv[i];
 670
 671                 if (*arg == '-') {
 672                         if (!prefixcmp(arg, "--upload-pack=")) {
 673                                 args.uploadpack = arg + 14;
 674                                 continue;
 675                         }
 676                         if (!prefixcmp(arg, "--exec=")) {
 677                                 args.uploadpack = arg + 7;
 678                                 continue;
 679                         }
 680                         if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
 681                                 args.quiet = 1;
 682                                 continue;
 683                         }
 684                         if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
 685                                 args.lock_pack = args.keep_pack;
 686                                 args.keep_pack = 1;
 687                                 continue;
 688                         }
 689                         if (!strcmp("--thin", arg)) {
 690                                 args.use_thin_pack = 1;
 691                                 continue;
 692                         }
 693                         if (!strcmp("--all", arg)) {
 694                                 args.fetch_all = 1;
 695                                 continue;
 696                         }
 697                         if (!strcmp("-v", arg)) {
 698                                 args.verbose = 1;
 699                                 continue;
 700                         }
 701                         if (!prefixcmp(arg, "--depth=")) {
 702                                 args.depth = strtol(arg + 8, NULL, 0);
 703                                 continue;
 704                         }
 705                         if (!strcmp("--no-progress", arg)) {
 706                                 args.no_progress = 1;
 707                                 continue;
 708                         }
 709                         usage(fetch_pack_usage);
 710                 }
 711                 dest = (char *)arg;
 712                 heads = (char **)(argv + i + 1);
 713                 nr_heads = argc - i - 1;
 714                 break;
 715         }
 716         if (!dest)
 717                 usage(fetch_pack_usage);
 718
 719         ref = fetch_pack(&args, dest, nr_heads, heads, NULL);
 720         ret = !ref;
 721
 722         while (ref) {
 723                 printf("%s %s\n",
 724                        sha1_to_hex(ref->old_sha1), ref->name);
 725                 ref = ref->next;
 726         }
 727
 728         return ret;
 729 }
 730
 731 struct ref *fetch_pack(struct fetch_pack_args *my_args,
 732                 const char *dest,
 733                 int nr_heads,
 734                 char **heads,
 735                 char **pack_lockfile)
 736 {
 737         int i, ret;
 738         int fd[2];
 739         struct child_process *conn;
 740         struct ref *ref;
 741         struct stat st;
 742
 743         fetch_pack_setup();
 744         memcpy(&args, my_args, sizeof(args));
 745         if (args.depth > 0) {
 746                 if (stat(git_path("shallow"), &st))
 747                         st.st_mtime = 0;
 748         }
 749
 750         conn = git_connect(fd, (char *)dest, args.uploadpack,
 751                           args.verbose ? CONNECT_VERBOSE : 0);
 752         if (heads && nr_heads)
 753                 nr_heads = remove_duplicates(nr_heads, heads);
 754         ref = do_fetch_pack(fd, nr_heads, heads, pack_lockfile);
 755         close(fd[0]);
 756         close(fd[1]);
 757         ret = finish_connect(conn);
 758
 759         if (!ret && nr_heads) {
 760                 /* If the heads to pull were given, we should have
 761                  * consumed all of them by matching the remote.
 762                  * Otherwise, 'git-fetch remote no-such-ref' would
 763                  * silently succeed without issuing an error.
 764                  */
 765                 for (i = 0; i < nr_heads; i++)
 766                         if (heads[i] && heads[i][0]) {
 767                                 error("no such remote ref %s", heads[i]);
 768                                 ret = 1;
 769                         }
 770         }
 771
 772         if (!ret && 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                         close(fd);
 797                         commit_lock_file(&lock);
 798                 }
 799         }
 800
 801         if (ret)
 802                 ref = NULL;
 803
 804         return ref;
 805 }