Andrew's git / gitweb.git / builtin-fetch-pack.c
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builtin-fetch-pack.con commit git-cvsserver runs hooks/post-receive (cdf6328)
   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
  12static int transfer_unpack_limit = -1;
  13static int fetch_unpack_limit = -1;
  14static int unpack_limit = 100;
  15static struct fetch_pack_args args = {
  16        /* .uploadpack = */ "git-upload-pack",
  17};
  18
  19static 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
  34static struct commit_list *rev_list;
  35static int non_common_revs, multi_ack, use_sideband;
  36
  37static 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
  52static 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
  68static 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
  99static 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
 144static 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        }
 270done:
 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
 294static struct commit_list *complete;
 295
 296static 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
 315static 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
 325static 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
 382static 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
 461static 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
 468static 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
 550static 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
 598static 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
 620static 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
 635static struct lock_file lock;
 636
 637static 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
 650int 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
 721struct 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}