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_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                                      (args.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         return recv_sideband("fetch-pack", xd[0], fd, 2);
 466 }
 467
 468 static int get_pack(int xd[2], char **pack_lockfile)
 469 {
 470         struct async demux;
 471         const char *argv[20];
 472         char keep_arg[256];
 473         char hdr_arg[256];
 474         const char **av;
 475         int do_keep = args.keep_pack;
 476         struct child_process cmd;
 477
 478         memset(&demux, 0, sizeof(demux));
 479         if (use_sideband) {
 480                 /* xd[] is talking with upload-pack; subprocess reads from
 481                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 482                  * through demux->out.
 483                  */
 484                 demux.proc = sideband_demux;
 485                 demux.data = xd;
 486                 if (start_async(&demux))
 487                         die("fetch-pack: unable to fork off sideband"
 488                             " demultiplexer");
 489         }
 490         else
 491                 demux.out = xd[0];
 492
 493         memset(&cmd, 0, sizeof(cmd));
 494         cmd.argv = argv;
 495         av = argv;
 496         *hdr_arg = 0;
 497         if (!args.keep_pack && unpack_limit) {
 498                 struct pack_header header;
 499
 500                 if (read_pack_header(demux.out, &header))
 501                         die("protocol error: bad pack header");
 502                 snprintf(hdr_arg, sizeof(hdr_arg), "--pack_header=%u,%u",
 503                          ntohl(header.hdr_version), ntohl(header.hdr_entries));
 504                 if (ntohl(header.hdr_entries) < unpack_limit)
 505                         do_keep = 0;
 506                 else
 507                         do_keep = 1;
 508         }
 509
 510         if (do_keep) {
 511                 if (pack_lockfile)
 512                         cmd.out = -1;
 513                 *av++ = "index-pack";
 514                 *av++ = "--stdin";
 515                 if (!args.quiet && !args.no_progress)
 516                         *av++ = "-v";
 517                 if (args.use_thin_pack)
 518                         *av++ = "--fix-thin";
 519                 if (args.lock_pack || unpack_limit) {
 520                         int s = sprintf(keep_arg,
 521                                         "--keep=fetch-pack %d on ", getpid());
 522                         if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 523                                 strcpy(keep_arg + s, "localhost");
 524                         *av++ = keep_arg;
 525                 }
 526         }
 527         else {
 528                 *av++ = "unpack-objects";
 529                 if (args.quiet)
 530                         *av++ = "-q";
 531         }
 532         if (*hdr_arg)
 533                 *av++ = hdr_arg;
 534         *av++ = NULL;
 535
 536         cmd.in = demux.out;
 537         cmd.git_cmd = 1;
 538         if (start_command(&cmd))
 539                 die("fetch-pack: unable to fork off %s", argv[0]);
 540         if (do_keep && pack_lockfile)
 541                 *pack_lockfile = index_pack_lockfile(cmd.out);
 542
 543         if (finish_command(&cmd))
 544                 die("%s failed", argv[0]);
 545         if (use_sideband && finish_async(&demux))
 546                 die("error in sideband demultiplexer");
 547         return 0;
 548 }
 549
 550 static struct ref *do_fetch_pack(int fd[2],
 551                 int nr_match,
 552                 char **match,
 553                 char **pack_lockfile)
 554 {
 555         struct ref *ref;
 556         unsigned char sha1[20];
 557
 558         get_remote_heads(fd[0], &ref, 0, NULL, 0);
 559         if (is_repository_shallow() && !server_supports("shallow"))
 560                 die("Server does not support shallow clients");
 561         if (server_supports("multi_ack")) {
 562                 if (args.verbose)
 563                         fprintf(stderr, "Server supports multi_ack\n");
 564                 multi_ack = 1;
 565         }
 566         if (server_supports("side-band-64k")) {
 567                 if (args.verbose)
 568                         fprintf(stderr, "Server supports side-band-64k\n");
 569                 use_sideband = 2;
 570         }
 571         else if (server_supports("side-band")) {
 572                 if (args.verbose)
 573                         fprintf(stderr, "Server supports side-band\n");
 574                 use_sideband = 1;
 575         }
 576         if (!ref) {
 577                 packet_flush(fd[1]);
 578                 die("no matching remote head");
 579         }
 580         if (everything_local(&ref, nr_match, match)) {
 581                 packet_flush(fd[1]);
 582                 goto all_done;
 583         }
 584         if (find_common(fd, sha1, ref) < 0)
 585                 if (!args.keep_pack)
 586                         /* When cloning, it is not unusual to have
 587                          * no common commit.
 588                          */
 589                         fprintf(stderr, "warning: no common commits\n");
 590
 591         if (get_pack(fd, pack_lockfile))
 592                 die("git-fetch-pack: fetch failed.");
 593
 594  all_done:
 595         return ref;
 596 }
 597
 598 static int remove_duplicates(int nr_heads, char **heads)
 599 {
 600         int src, dst;
 601
 602         for (src = dst = 0; src < nr_heads; src++) {
 603                 /* If heads[src] is different from any of
 604                  * heads[0..dst], push it in.
 605                  */
 606                 int i;
 607                 for (i = 0; i < dst; i++) {
 608                         if (!strcmp(heads[i], heads[src]))
 609                                 break;
 610                 }
 611                 if (i < dst)
 612                         continue;
 613                 if (src != dst)
 614                         heads[dst] = heads[src];
 615                 dst++;
 616         }
 617         return dst;
 618 }
 619
 620 static int fetch_pack_config(const char *var, const char *value)
 621 {
 622         if (strcmp(var, "fetch.unpacklimit") == 0) {
 623                 fetch_unpack_limit = git_config_int(var, value);
 624                 return 0;
 625         }
 626
 627         if (strcmp(var, "transfer.unpacklimit") == 0) {
 628                 transfer_unpack_limit = git_config_int(var, value);
 629                 return 0;
 630         }
 631
 632         return git_default_config(var, value);
 633 }
 634
 635 static struct lock_file lock;
 636
 637 static void fetch_pack_setup(void)
 638 {
 639         static int did_setup;
 640         if (did_setup)
 641                 return;
 642         git_config(fetch_pack_config);
 643         if (0 <= transfer_unpack_limit)
 644                 unpack_limit = transfer_unpack_limit;
 645         else if (0 <= fetch_unpack_limit)
 646                 unpack_limit = fetch_unpack_limit;
 647         did_setup = 1;
 648 }
 649
 650 int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 651 {
 652         int i, ret, nr_heads;
 653         struct ref *ref;
 654         char *dest = NULL, **heads;
 655
 656         nr_heads = 0;
 657         heads = NULL;
 658         for (i = 1; i < argc; i++) {
 659                 const char *arg = argv[i];
 660
 661                 if (*arg == '-') {
 662                         if (!prefixcmp(arg, "--upload-pack=")) {
 663                                 args.uploadpack = arg + 14;
 664                                 continue;
 665                         }
 666                         if (!prefixcmp(arg, "--exec=")) {
 667                                 args.uploadpack = arg + 7;
 668                                 continue;
 669                         }
 670                         if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
 671                                 args.quiet = 1;
 672                                 continue;
 673                         }
 674                         if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
 675                                 args.lock_pack = args.keep_pack;
 676                                 args.keep_pack = 1;
 677                                 continue;
 678                         }
 679                         if (!strcmp("--thin", arg)) {
 680                                 args.use_thin_pack = 1;
 681                                 continue;
 682                         }
 683                         if (!strcmp("--all", arg)) {
 684                                 args.fetch_all = 1;
 685                                 continue;
 686                         }
 687                         if (!strcmp("-v", arg)) {
 688                                 args.verbose = 1;
 689                                 continue;
 690                         }
 691                         if (!prefixcmp(arg, "--depth=")) {
 692                                 args.depth = strtol(arg + 8, NULL, 0);
 693                                 continue;
 694                         }
 695                         if (!strcmp("--no-progress", arg)) {
 696                                 args.no_progress = 1;
 697                                 continue;
 698                         }
 699                         usage(fetch_pack_usage);
 700                 }
 701                 dest = (char *)arg;
 702                 heads = (char **)(argv + i + 1);
 703                 nr_heads = argc - i - 1;
 704                 break;
 705         }
 706         if (!dest)
 707                 usage(fetch_pack_usage);
 708
 709         ref = fetch_pack(&args, dest, nr_heads, heads, NULL);
 710         ret = !ref;
 711
 712         while (ref) {
 713                 printf("%s %s\n",
 714                        sha1_to_hex(ref->old_sha1), ref->name);
 715                 ref = ref->next;
 716         }
 717
 718         return ret;
 719 }
 720
 721 struct ref *fetch_pack(struct fetch_pack_args *my_args,
 722                 const char *dest,
 723                 int nr_heads,
 724                 char **heads,
 725                 char **pack_lockfile)
 726 {
 727         int i, ret;
 728         int fd[2];
 729         struct child_process *conn;
 730         struct ref *ref;
 731         struct stat st;
 732
 733         fetch_pack_setup();
 734         memcpy(&args, my_args, sizeof(args));
 735         if (args.depth > 0) {
 736                 if (stat(git_path("shallow"), &st))
 737                         st.st_mtime = 0;
 738         }
 739
 740         conn = git_connect(fd, (char *)dest, args.uploadpack,
 741                           args.verbose ? CONNECT_VERBOSE : 0);
 742         if (heads && nr_heads)
 743                 nr_heads = remove_duplicates(nr_heads, heads);
 744         ref = do_fetch_pack(fd, nr_heads, heads, pack_lockfile);
 745         close(fd[0]);
 746         close(fd[1]);
 747         ret = finish_connect(conn);
 748
 749         if (!ret && nr_heads) {
 750                 /* If the heads to pull were given, we should have
 751                  * consumed all of them by matching the remote.
 752                  * Otherwise, 'git-fetch remote no-such-ref' would
 753                  * silently succeed without issuing an error.
 754                  */
 755                 for (i = 0; i < nr_heads; i++)
 756                         if (heads[i] && heads[i][0]) {
 757                                 error("no such remote ref %s", heads[i]);
 758                                 ret = 1;
 759                         }
 760         }
 761
 762         if (!ret && args.depth > 0) {
 763                 struct cache_time mtime;
 764                 char *shallow = git_path("shallow");
 765                 int fd;
 766
 767                 mtime.sec = st.st_mtime;
 768 #ifdef USE_NSEC
 769                 mtime.usec = st.st_mtim.usec;
 770 #endif
 771                 if (stat(shallow, &st)) {
 772                         if (mtime.sec)
 773                                 die("shallow file was removed during fetch");
 774                 } else if (st.st_mtime != mtime.sec
 775 #ifdef USE_NSEC
 776                                 || st.st_mtim.usec != mtime.usec
 777 #endif
 778                           )
 779                         die("shallow file was changed during fetch");
 780
 781                 fd = hold_lock_file_for_update(&lock, shallow, 1);
 782                 if (!write_shallow_commits(fd, 0)) {
 783                         unlink(shallow);
 784                         rollback_lock_file(&lock);
 785                 } else {
 786                         close(fd);
 787                         commit_lock_file(&lock);
 788                 }
 789         }
 790
 791         if (ret)
 792                 ref = NULL;
 793
 794         return ref;
 795 }