Andrew's git / gitweb.git / fetch-pack.c
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fetch-pack.con commit t6111: allow checking the parents as well (e16f434)
   1#include "cache.h"
   2#include "refs.h"
   3#include "pkt-line.h"
   4#include "commit.h"
   5#include "tag.h"
   6#include "exec_cmd.h"
   7#include "pack.h"
   8#include "sideband.h"
   9#include "fetch-pack.h"
  10#include "remote.h"
  11#include "run-command.h"
  12#include "transport.h"
  13#include "version.h"
  14
  15static int transfer_unpack_limit = -1;
  16static int fetch_unpack_limit = -1;
  17static int unpack_limit = 100;
  18static int prefer_ofs_delta = 1;
  19static int no_done;
  20static int fetch_fsck_objects = -1;
  21static int transfer_fsck_objects = -1;
  22static int agent_supported;
  23
  24#define COMPLETE        (1U << 0)
  25#define COMMON          (1U << 1)
  26#define COMMON_REF      (1U << 2)
  27#define SEEN            (1U << 3)
  28#define POPPED          (1U << 4)
  29
  30static int marked;
  31
  32/*
  33 * After sending this many "have"s if we do not get any new ACK , we
  34 * give up traversing our history.
  35 */
  36#define MAX_IN_VAIN 256
  37
  38static struct commit_list *rev_list;
  39static int non_common_revs, multi_ack, use_sideband, allow_tip_sha1_in_want;
  40
  41static void rev_list_push(struct commit *commit, int mark)
  42{
  43        if (!(commit->object.flags & mark)) {
  44                commit->object.flags |= mark;
  45
  46                if (!(commit->object.parsed))
  47                        if (parse_commit(commit))
  48                                return;
  49
  50                commit_list_insert_by_date(commit, &rev_list);
  51
  52                if (!(commit->object.flags & COMMON))
  53                        non_common_revs++;
  54        }
  55}
  56
  57static int rev_list_insert_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
  58{
  59        struct object *o = deref_tag(parse_object(sha1), refname, 0);
  60
  61        if (o && o->type == OBJ_COMMIT)
  62                rev_list_push((struct commit *)o, SEEN);
  63
  64        return 0;
  65}
  66
  67static int clear_marks(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
  68{
  69        struct object *o = deref_tag(parse_object(sha1), refname, 0);
  70
  71        if (o && o->type == OBJ_COMMIT)
  72                clear_commit_marks((struct commit *)o,
  73                                   COMMON | COMMON_REF | SEEN | POPPED);
  74        return 0;
  75}
  76
  77/*
  78   This function marks a rev and its ancestors as common.
  79   In some cases, it is desirable to mark only the ancestors (for example
  80   when only the server does not yet know that they are common).
  81*/
  82
  83static void mark_common(struct commit *commit,
  84                int ancestors_only, int dont_parse)
  85{
  86        if (commit != NULL && !(commit->object.flags & COMMON)) {
  87                struct object *o = (struct object *)commit;
  88
  89                if (!ancestors_only)
  90                        o->flags |= COMMON;
  91
  92                if (!(o->flags & SEEN))
  93                        rev_list_push(commit, SEEN);
  94                else {
  95                        struct commit_list *parents;
  96
  97                        if (!ancestors_only && !(o->flags & POPPED))
  98                                non_common_revs--;
  99                        if (!o->parsed && !dont_parse)
 100                                if (parse_commit(commit))
 101                                        return;
 102
 103                        for (parents = commit->parents;
 104                                        parents;
 105                                        parents = parents->next)
 106                                mark_common(parents->item, 0, dont_parse);
 107                }
 108        }
 109}
 110
 111/*
 112  Get the next rev to send, ignoring the common.
 113*/
 114
 115static const unsigned char *get_rev(void)
 116{
 117        struct commit *commit = NULL;
 118
 119        while (commit == NULL) {
 120                unsigned int mark;
 121                struct commit_list *parents;
 122
 123                if (rev_list == NULL || non_common_revs == 0)
 124                        return NULL;
 125
 126                commit = rev_list->item;
 127                if (!commit->object.parsed)
 128                        parse_commit(commit);
 129                parents = commit->parents;
 130
 131                commit->object.flags |= POPPED;
 132                if (!(commit->object.flags & COMMON))
 133                        non_common_revs--;
 134
 135                if (commit->object.flags & COMMON) {
 136                        /* do not send "have", and ignore ancestors */
 137                        commit = NULL;
 138                        mark = COMMON | SEEN;
 139                } else if (commit->object.flags & COMMON_REF)
 140                        /* send "have", and ignore ancestors */
 141                        mark = COMMON | SEEN;
 142                else
 143                        /* send "have", also for its ancestors */
 144                        mark = SEEN;
 145
 146                while (parents) {
 147                        if (!(parents->item->object.flags & SEEN))
 148                                rev_list_push(parents->item, mark);
 149                        if (mark & COMMON)
 150                                mark_common(parents->item, 1, 0);
 151                        parents = parents->next;
 152                }
 153
 154                rev_list = rev_list->next;
 155        }
 156
 157        return commit->object.sha1;
 158}
 159
 160enum ack_type {
 161        NAK = 0,
 162        ACK,
 163        ACK_continue,
 164        ACK_common,
 165        ACK_ready
 166};
 167
 168static void consume_shallow_list(struct fetch_pack_args *args, int fd)
 169{
 170        if (args->stateless_rpc && args->depth > 0) {
 171                /* If we sent a depth we will get back "duplicate"
 172                 * shallow and unshallow commands every time there
 173                 * is a block of have lines exchanged.
 174                 */
 175                char *line;
 176                while ((line = packet_read_line(fd, NULL))) {
 177                        if (!prefixcmp(line, "shallow "))
 178                                continue;
 179                        if (!prefixcmp(line, "unshallow "))
 180                                continue;
 181                        die("git fetch-pack: expected shallow list");
 182                }
 183        }
 184}
 185
 186struct write_shallow_data {
 187        struct strbuf *out;
 188        int use_pack_protocol;
 189        int count;
 190};
 191
 192static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
 193{
 194        struct write_shallow_data *data = cb_data;
 195        const char *hex = sha1_to_hex(graft->sha1);
 196        data->count++;
 197        if (data->use_pack_protocol)
 198                packet_buf_write(data->out, "shallow %s", hex);
 199        else {
 200                strbuf_addstr(data->out, hex);
 201                strbuf_addch(data->out, '\n');
 202        }
 203        return 0;
 204}
 205
 206static int write_shallow_commits(struct strbuf *out, int use_pack_protocol)
 207{
 208        struct write_shallow_data data;
 209        data.out = out;
 210        data.use_pack_protocol = use_pack_protocol;
 211        data.count = 0;
 212        for_each_commit_graft(write_one_shallow, &data);
 213        return data.count;
 214}
 215
 216static enum ack_type get_ack(int fd, unsigned char *result_sha1)
 217{
 218        int len;
 219        char *line = packet_read_line(fd, &len);
 220
 221        if (!len)
 222                die("git fetch-pack: expected ACK/NAK, got EOF");
 223        if (!strcmp(line, "NAK"))
 224                return NAK;
 225        if (!prefixcmp(line, "ACK ")) {
 226                if (!get_sha1_hex(line+4, result_sha1)) {
 227                        if (len < 45)
 228                                return ACK;
 229                        if (strstr(line+45, "continue"))
 230                                return ACK_continue;
 231                        if (strstr(line+45, "common"))
 232                                return ACK_common;
 233                        if (strstr(line+45, "ready"))
 234                                return ACK_ready;
 235                        return ACK;
 236                }
 237        }
 238        die("git fetch_pack: expected ACK/NAK, got '%s'", line);
 239}
 240
 241static void send_request(struct fetch_pack_args *args,
 242                         int fd, struct strbuf *buf)
 243{
 244        if (args->stateless_rpc) {
 245                send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 246                packet_flush(fd);
 247        } else
 248                write_or_die(fd, buf->buf, buf->len);
 249}
 250
 251static void insert_one_alternate_ref(const struct ref *ref, void *unused)
 252{
 253        rev_list_insert_ref(NULL, ref->old_sha1, 0, NULL);
 254}
 255
 256#define INITIAL_FLUSH 16
 257#define PIPESAFE_FLUSH 32
 258#define LARGE_FLUSH 1024
 259
 260static int next_flush(struct fetch_pack_args *args, int count)
 261{
 262        int flush_limit = args->stateless_rpc ? LARGE_FLUSH : PIPESAFE_FLUSH;
 263
 264        if (count < flush_limit)
 265                count <<= 1;
 266        else
 267                count += flush_limit;
 268        return count;
 269}
 270
 271static int find_common(struct fetch_pack_args *args,
 272                       int fd[2], unsigned char *result_sha1,
 273                       struct ref *refs)
 274{
 275        int fetching;
 276        int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 277        const unsigned char *sha1;
 278        unsigned in_vain = 0;
 279        int got_continue = 0;
 280        int got_ready = 0;
 281        struct strbuf req_buf = STRBUF_INIT;
 282        size_t state_len = 0;
 283
 284        if (args->stateless_rpc && multi_ack == 1)
 285                die("--stateless-rpc requires multi_ack_detailed");
 286        if (marked)
 287                for_each_ref(clear_marks, NULL);
 288        marked = 1;
 289
 290        for_each_ref(rev_list_insert_ref, NULL);
 291        for_each_alternate_ref(insert_one_alternate_ref, NULL);
 292
 293        fetching = 0;
 294        for ( ; refs ; refs = refs->next) {
 295                unsigned char *remote = refs->old_sha1;
 296                const char *remote_hex;
 297                struct object *o;
 298
 299                /*
 300                 * If that object is complete (i.e. it is an ancestor of a
 301                 * local ref), we tell them we have it but do not have to
 302                 * tell them about its ancestors, which they already know
 303                 * about.
 304                 *
 305                 * We use lookup_object here because we are only
 306                 * interested in the case we *know* the object is
 307                 * reachable and we have already scanned it.
 308                 */
 309                if (((o = lookup_object(remote)) != NULL) &&
 310                                (o->flags & COMPLETE)) {
 311                        continue;
 312                }
 313
 314                remote_hex = sha1_to_hex(remote);
 315                if (!fetching) {
 316                        struct strbuf c = STRBUF_INIT;
 317                        if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 318                        if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 319                        if (no_done)            strbuf_addstr(&c, " no-done");
 320                        if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 321                        if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 322                        if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
 323                        if (args->no_progress)   strbuf_addstr(&c, " no-progress");
 324                        if (args->include_tag)   strbuf_addstr(&c, " include-tag");
 325                        if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 326                        if (agent_supported)    strbuf_addf(&c, " agent=%s",
 327                                                            git_user_agent_sanitized());
 328                        packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 329                        strbuf_release(&c);
 330                } else
 331                        packet_buf_write(&req_buf, "want %s\n", remote_hex);
 332                fetching++;
 333        }
 334
 335        if (!fetching) {
 336                strbuf_release(&req_buf);
 337                packet_flush(fd[1]);
 338                return 1;
 339        }
 340
 341        if (is_repository_shallow())
 342                write_shallow_commits(&req_buf, 1);
 343        if (args->depth > 0)
 344                packet_buf_write(&req_buf, "deepen %d", args->depth);
 345        packet_buf_flush(&req_buf);
 346        state_len = req_buf.len;
 347
 348        if (args->depth > 0) {
 349                char *line;
 350                unsigned char sha1[20];
 351
 352                send_request(args, fd[1], &req_buf);
 353                while ((line = packet_read_line(fd[0], NULL))) {
 354                        if (!prefixcmp(line, "shallow ")) {
 355                                if (get_sha1_hex(line + 8, sha1))
 356                                        die("invalid shallow line: %s", line);
 357                                register_shallow(sha1);
 358                                continue;
 359                        }
 360                        if (!prefixcmp(line, "unshallow ")) {
 361                                if (get_sha1_hex(line + 10, sha1))
 362                                        die("invalid unshallow line: %s", line);
 363                                if (!lookup_object(sha1))
 364                                        die("object not found: %s", line);
 365                                /* make sure that it is parsed as shallow */
 366                                if (!parse_object(sha1))
 367                                        die("error in object: %s", line);
 368                                if (unregister_shallow(sha1))
 369                                        die("no shallow found: %s", line);
 370                                continue;
 371                        }
 372                        die("expected shallow/unshallow, got %s", line);
 373                }
 374        } else if (!args->stateless_rpc)
 375                send_request(args, fd[1], &req_buf);
 376
 377        if (!args->stateless_rpc) {
 378                /* If we aren't using the stateless-rpc interface
 379                 * we don't need to retain the headers.
 380                 */
 381                strbuf_setlen(&req_buf, 0);
 382                state_len = 0;
 383        }
 384
 385        flushes = 0;
 386        retval = -1;
 387        while ((sha1 = get_rev())) {
 388                packet_buf_write(&req_buf, "have %s\n", sha1_to_hex(sha1));
 389                if (args->verbose)
 390                        fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 391                in_vain++;
 392                if (flush_at <= ++count) {
 393                        int ack;
 394
 395                        packet_buf_flush(&req_buf);
 396                        send_request(args, fd[1], &req_buf);
 397                        strbuf_setlen(&req_buf, state_len);
 398                        flushes++;
 399                        flush_at = next_flush(args, count);
 400
 401                        /*
 402                         * We keep one window "ahead" of the other side, and
 403                         * will wait for an ACK only on the next one
 404                         */
 405                        if (!args->stateless_rpc && count == INITIAL_FLUSH)
 406                                continue;
 407
 408                        consume_shallow_list(args, fd[0]);
 409                        do {
 410                                ack = get_ack(fd[0], result_sha1);
 411                                if (args->verbose && ack)
 412                                        fprintf(stderr, "got ack %d %s\n", ack,
 413                                                        sha1_to_hex(result_sha1));
 414                                switch (ack) {
 415                                case ACK:
 416                                        flushes = 0;
 417                                        multi_ack = 0;
 418                                        retval = 0;
 419                                        goto done;
 420                                case ACK_common:
 421                                case ACK_ready:
 422                                case ACK_continue: {
 423                                        struct commit *commit =
 424                                                lookup_commit(result_sha1);
 425                                        if (!commit)
 426                                                die("invalid commit %s", sha1_to_hex(result_sha1));
 427                                        if (args->stateless_rpc
 428                                         && ack == ACK_common
 429                                         && !(commit->object.flags & COMMON)) {
 430                                                /* We need to replay the have for this object
 431                                                 * on the next RPC request so the peer knows
 432                                                 * it is in common with us.
 433                                                 */
 434                                                const char *hex = sha1_to_hex(result_sha1);
 435                                                packet_buf_write(&req_buf, "have %s\n", hex);
 436                                                state_len = req_buf.len;
 437                                        }
 438                                        mark_common(commit, 0, 1);
 439                                        retval = 0;
 440                                        in_vain = 0;
 441                                        got_continue = 1;
 442                                        if (ack == ACK_ready) {
 443                                                rev_list = NULL;
 444                                                got_ready = 1;
 445                                        }
 446                                        break;
 447                                        }
 448                                }
 449                        } while (ack);
 450                        flushes--;
 451                        if (got_continue && MAX_IN_VAIN < in_vain) {
 452                                if (args->verbose)
 453                                        fprintf(stderr, "giving up\n");
 454                                break; /* give up */
 455                        }
 456                }
 457        }
 458done:
 459        if (!got_ready || !no_done) {
 460                packet_buf_write(&req_buf, "done\n");
 461                send_request(args, fd[1], &req_buf);
 462        }
 463        if (args->verbose)
 464                fprintf(stderr, "done\n");
 465        if (retval != 0) {
 466                multi_ack = 0;
 467                flushes++;
 468        }
 469        strbuf_release(&req_buf);
 470
 471        consume_shallow_list(args, fd[0]);
 472        while (flushes || multi_ack) {
 473                int ack = get_ack(fd[0], result_sha1);
 474                if (ack) {
 475                        if (args->verbose)
 476                                fprintf(stderr, "got ack (%d) %s\n", ack,
 477                                        sha1_to_hex(result_sha1));
 478                        if (ack == ACK)
 479                                return 0;
 480                        multi_ack = 1;
 481                        continue;
 482                }
 483                flushes--;
 484        }
 485        /* it is no error to fetch into a completely empty repo */
 486        return count ? retval : 0;
 487}
 488
 489static struct commit_list *complete;
 490
 491static int mark_complete(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 492{
 493        struct object *o = parse_object(sha1);
 494
 495        while (o && o->type == OBJ_TAG) {
 496                struct tag *t = (struct tag *) o;
 497                if (!t->tagged)
 498                        break; /* broken repository */
 499                o->flags |= COMPLETE;
 500                o = parse_object(t->tagged->sha1);
 501        }
 502        if (o && o->type == OBJ_COMMIT) {
 503                struct commit *commit = (struct commit *)o;
 504                if (!(commit->object.flags & COMPLETE)) {
 505                        commit->object.flags |= COMPLETE;
 506                        commit_list_insert_by_date(commit, &complete);
 507                }
 508        }
 509        return 0;
 510}
 511
 512static void mark_recent_complete_commits(struct fetch_pack_args *args,
 513                                         unsigned long cutoff)
 514{
 515        while (complete && cutoff <= complete->item->date) {
 516                if (args->verbose)
 517                        fprintf(stderr, "Marking %s as complete\n",
 518                                sha1_to_hex(complete->item->object.sha1));
 519                pop_most_recent_commit(&complete, COMPLETE);
 520        }
 521}
 522
 523static void filter_refs(struct fetch_pack_args *args,
 524                        struct ref **refs,
 525                        struct ref **sought, int nr_sought)
 526{
 527        struct ref *newlist = NULL;
 528        struct ref **newtail = &newlist;
 529        struct ref *ref, *next;
 530        int i;
 531
 532        i = 0;
 533        for (ref = *refs; ref; ref = next) {
 534                int keep = 0;
 535                next = ref->next;
 536
 537                if (!memcmp(ref->name, "refs/", 5) &&
 538                    check_refname_format(ref->name + 5, 0))
 539                        ; /* trash */
 540                else {
 541                        while (i < nr_sought) {
 542                                int cmp = strcmp(ref->name, sought[i]->name);
 543                                if (cmp < 0)
 544                                        break; /* definitely do not have it */
 545                                else if (cmp == 0) {
 546                                        keep = 1; /* definitely have it */
 547                                        sought[i]->matched = 1;
 548                                }
 549                                i++;
 550                        }
 551                }
 552
 553                if (!keep && args->fetch_all &&
 554                    (!args->depth || prefixcmp(ref->name, "refs/tags/")))
 555                        keep = 1;
 556
 557                if (keep) {
 558                        *newtail = ref;
 559                        ref->next = NULL;
 560                        newtail = &ref->next;
 561                } else {
 562                        free(ref);
 563                }
 564        }
 565
 566        /* Append unmatched requests to the list */
 567        if (allow_tip_sha1_in_want) {
 568                for (i = 0; i < nr_sought; i++) {
 569                        ref = sought[i];
 570                        if (ref->matched)
 571                                continue;
 572                        if (get_sha1_hex(ref->name, ref->old_sha1))
 573                                continue;
 574
 575                        ref->matched = 1;
 576                        *newtail = ref;
 577                        ref->next = NULL;
 578                        newtail = &ref->next;
 579                }
 580        }
 581        *refs = newlist;
 582}
 583
 584static void mark_alternate_complete(const struct ref *ref, void *unused)
 585{
 586        mark_complete(NULL, ref->old_sha1, 0, NULL);
 587}
 588
 589static int everything_local(struct fetch_pack_args *args,
 590                            struct ref **refs,
 591                            struct ref **sought, int nr_sought)
 592{
 593        struct ref *ref;
 594        int retval;
 595        unsigned long cutoff = 0;
 596
 597        save_commit_buffer = 0;
 598
 599        for (ref = *refs; ref; ref = ref->next) {
 600                struct object *o;
 601
 602                if (!has_sha1_file(ref->old_sha1))
 603                        continue;
 604
 605                o = parse_object(ref->old_sha1);
 606                if (!o)
 607                        continue;
 608
 609                /* We already have it -- which may mean that we were
 610                 * in sync with the other side at some time after
 611                 * that (it is OK if we guess wrong here).
 612                 */
 613                if (o->type == OBJ_COMMIT) {
 614                        struct commit *commit = (struct commit *)o;
 615                        if (!cutoff || cutoff < commit->date)
 616                                cutoff = commit->date;
 617                }
 618        }
 619
 620        if (!args->depth) {
 621                for_each_ref(mark_complete, NULL);
 622                for_each_alternate_ref(mark_alternate_complete, NULL);
 623                if (cutoff)
 624                        mark_recent_complete_commits(args, cutoff);
 625        }
 626
 627        /*
 628         * Mark all complete remote refs as common refs.
 629         * Don't mark them common yet; the server has to be told so first.
 630         */
 631        for (ref = *refs; ref; ref = ref->next) {
 632                struct object *o = deref_tag(lookup_object(ref->old_sha1),
 633                                             NULL, 0);
 634
 635                if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 636                        continue;
 637
 638                if (!(o->flags & SEEN)) {
 639                        rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 640
 641                        mark_common((struct commit *)o, 1, 1);
 642                }
 643        }
 644
 645        filter_refs(args, refs, sought, nr_sought);
 646
 647        for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 648                const unsigned char *remote = ref->old_sha1;
 649                unsigned char local[20];
 650                struct object *o;
 651
 652                o = lookup_object(remote);
 653                if (!o || !(o->flags & COMPLETE)) {
 654                        retval = 0;
 655                        if (!args->verbose)
 656                                continue;
 657                        fprintf(stderr,
 658                                "want %s (%s)\n", sha1_to_hex(remote),
 659                                ref->name);
 660                        continue;
 661                }
 662
 663                hashcpy(ref->new_sha1, local);
 664                if (!args->verbose)
 665                        continue;
 666                fprintf(stderr,
 667                        "already have %s (%s)\n", sha1_to_hex(remote),
 668                        ref->name);
 669        }
 670        return retval;
 671}
 672
 673static int sideband_demux(int in, int out, void *data)
 674{
 675        int *xd = data;
 676
 677        int ret = recv_sideband("fetch-pack", xd[0], out);
 678        close(out);
 679        return ret;
 680}
 681
 682static int get_pack(struct fetch_pack_args *args,
 683                    int xd[2], char **pack_lockfile)
 684{
 685        struct async demux;
 686        const char *argv[20];
 687        char keep_arg[256];
 688        char hdr_arg[256];
 689        const char **av;
 690        int do_keep = args->keep_pack;
 691        struct child_process cmd;
 692
 693        memset(&demux, 0, sizeof(demux));
 694        if (use_sideband) {
 695                /* xd[] is talking with upload-pack; subprocess reads from
 696                 * xd[0], spits out band#2 to stderr, and feeds us band#1
 697                 * through demux->out.
 698                 */
 699                demux.proc = sideband_demux;
 700                demux.data = xd;
 701                demux.out = -1;
 702                if (start_async(&demux))
 703                        die("fetch-pack: unable to fork off sideband"
 704                            " demultiplexer");
 705        }
 706        else
 707                demux.out = xd[0];
 708
 709        memset(&cmd, 0, sizeof(cmd));
 710        cmd.argv = argv;
 711        av = argv;
 712        *hdr_arg = 0;
 713        if (!args->keep_pack && unpack_limit) {
 714                struct pack_header header;
 715
 716                if (read_pack_header(demux.out, &header))
 717                        die("protocol error: bad pack header");
 718                snprintf(hdr_arg, sizeof(hdr_arg),
 719                         "--pack_header=%"PRIu32",%"PRIu32,
 720                         ntohl(header.hdr_version), ntohl(header.hdr_entries));
 721                if (ntohl(header.hdr_entries) < unpack_limit)
 722                        do_keep = 0;
 723                else
 724                        do_keep = 1;
 725        }
 726
 727        if (do_keep) {
 728                if (pack_lockfile)
 729                        cmd.out = -1;
 730                *av++ = "index-pack";
 731                *av++ = "--stdin";
 732                if (!args->quiet && !args->no_progress)
 733                        *av++ = "-v";
 734                if (args->use_thin_pack)
 735                        *av++ = "--fix-thin";
 736                if (args->lock_pack || unpack_limit) {
 737                        int s = sprintf(keep_arg,
 738                                        "--keep=fetch-pack %"PRIuMAX " on ", (uintmax_t) getpid());
 739                        if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 740                                strcpy(keep_arg + s, "localhost");
 741                        *av++ = keep_arg;
 742                }
 743        }
 744        else {
 745                *av++ = "unpack-objects";
 746                if (args->quiet || args->no_progress)
 747                        *av++ = "-q";
 748        }
 749        if (*hdr_arg)
 750                *av++ = hdr_arg;
 751        if (fetch_fsck_objects >= 0
 752            ? fetch_fsck_objects
 753            : transfer_fsck_objects >= 0
 754            ? transfer_fsck_objects
 755            : 0)
 756                *av++ = "--strict";
 757        *av++ = NULL;
 758
 759        cmd.in = demux.out;
 760        cmd.git_cmd = 1;
 761        if (start_command(&cmd))
 762                die("fetch-pack: unable to fork off %s", argv[0]);
 763        if (do_keep && pack_lockfile) {
 764                *pack_lockfile = index_pack_lockfile(cmd.out);
 765                close(cmd.out);
 766        }
 767
 768        if (finish_command(&cmd))
 769                die("%s failed", argv[0]);
 770        if (use_sideband && finish_async(&demux))
 771                die("error in sideband demultiplexer");
 772        return 0;
 773}
 774
 775static int cmp_ref_by_name(const void *a_, const void *b_)
 776{
 777        const struct ref *a = *((const struct ref **)a_);
 778        const struct ref *b = *((const struct ref **)b_);
 779        return strcmp(a->name, b->name);
 780}
 781
 782static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 783                                 int fd[2],
 784                                 const struct ref *orig_ref,
 785                                 struct ref **sought, int nr_sought,
 786                                 char **pack_lockfile)
 787{
 788        struct ref *ref = copy_ref_list(orig_ref);
 789        unsigned char sha1[20];
 790        const char *agent_feature;
 791        int agent_len;
 792
 793        sort_ref_list(&ref, ref_compare_name);
 794        qsort(sought, nr_sought, sizeof(*sought), cmp_ref_by_name);
 795
 796        if (is_repository_shallow() && !server_supports("shallow"))
 797                die("Server does not support shallow clients");
 798        if (server_supports("multi_ack_detailed")) {
 799                if (args->verbose)
 800                        fprintf(stderr, "Server supports multi_ack_detailed\n");
 801                multi_ack = 2;
 802                if (server_supports("no-done")) {
 803                        if (args->verbose)
 804                                fprintf(stderr, "Server supports no-done\n");
 805                        if (args->stateless_rpc)
 806                                no_done = 1;
 807                }
 808        }
 809        else if (server_supports("multi_ack")) {
 810                if (args->verbose)
 811                        fprintf(stderr, "Server supports multi_ack\n");
 812                multi_ack = 1;
 813        }
 814        if (server_supports("side-band-64k")) {
 815                if (args->verbose)
 816                        fprintf(stderr, "Server supports side-band-64k\n");
 817                use_sideband = 2;
 818        }
 819        else if (server_supports("side-band")) {
 820                if (args->verbose)
 821                        fprintf(stderr, "Server supports side-band\n");
 822                use_sideband = 1;
 823        }
 824        if (server_supports("allow-tip-sha1-in-want")) {
 825                if (args->verbose)
 826                        fprintf(stderr, "Server supports allow-tip-sha1-in-want\n");
 827                allow_tip_sha1_in_want = 1;
 828        }
 829        if (!server_supports("thin-pack"))
 830                args->use_thin_pack = 0;
 831        if (!server_supports("no-progress"))
 832                args->no_progress = 0;
 833        if (!server_supports("include-tag"))
 834                args->include_tag = 0;
 835        if (server_supports("ofs-delta")) {
 836                if (args->verbose)
 837                        fprintf(stderr, "Server supports ofs-delta\n");
 838        } else
 839                prefer_ofs_delta = 0;
 840
 841        if ((agent_feature = server_feature_value("agent", &agent_len))) {
 842                agent_supported = 1;
 843                if (args->verbose && agent_len)
 844                        fprintf(stderr, "Server version is %.*s\n",
 845                                agent_len, agent_feature);
 846        }
 847
 848        if (everything_local(args, &ref, sought, nr_sought)) {
 849                packet_flush(fd[1]);
 850                goto all_done;
 851        }
 852        if (find_common(args, fd, sha1, ref) < 0)
 853                if (!args->keep_pack)
 854                        /* When cloning, it is not unusual to have
 855                         * no common commit.
 856                         */
 857                        warning("no common commits");
 858
 859        if (args->stateless_rpc)
 860                packet_flush(fd[1]);
 861        if (get_pack(args, fd, pack_lockfile))
 862                die("git fetch-pack: fetch failed.");
 863
 864 all_done:
 865        return ref;
 866}
 867
 868static int fetch_pack_config(const char *var, const char *value, void *cb)
 869{
 870        if (strcmp(var, "fetch.unpacklimit") == 0) {
 871                fetch_unpack_limit = git_config_int(var, value);
 872                return 0;
 873        }
 874
 875        if (strcmp(var, "transfer.unpacklimit") == 0) {
 876                transfer_unpack_limit = git_config_int(var, value);
 877                return 0;
 878        }
 879
 880        if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
 881                prefer_ofs_delta = git_config_bool(var, value);
 882                return 0;
 883        }
 884
 885        if (!strcmp(var, "fetch.fsckobjects")) {
 886                fetch_fsck_objects = git_config_bool(var, value);
 887                return 0;
 888        }
 889
 890        if (!strcmp(var, "transfer.fsckobjects")) {
 891                transfer_fsck_objects = git_config_bool(var, value);
 892                return 0;
 893        }
 894
 895        return git_default_config(var, value, cb);
 896}
 897
 898static void fetch_pack_setup(void)
 899{
 900        static int did_setup;
 901        if (did_setup)
 902                return;
 903        git_config(fetch_pack_config, NULL);
 904        if (0 <= transfer_unpack_limit)
 905                unpack_limit = transfer_unpack_limit;
 906        else if (0 <= fetch_unpack_limit)
 907                unpack_limit = fetch_unpack_limit;
 908        did_setup = 1;
 909}
 910
 911static int remove_duplicates_in_refs(struct ref **ref, int nr)
 912{
 913        struct string_list names = STRING_LIST_INIT_NODUP;
 914        int src, dst;
 915
 916        for (src = dst = 0; src < nr; src++) {
 917                struct string_list_item *item;
 918                item = string_list_insert(&names, ref[src]->name);
 919                if (item->util)
 920                        continue; /* already have it */
 921                item->util = ref[src];
 922                if (src != dst)
 923                        ref[dst] = ref[src];
 924                dst++;
 925        }
 926        for (src = dst; src < nr; src++)
 927                ref[src] = NULL;
 928        string_list_clear(&names, 0);
 929        return dst;
 930}
 931
 932struct ref *fetch_pack(struct fetch_pack_args *args,
 933                       int fd[], struct child_process *conn,
 934                       const struct ref *ref,
 935                       const char *dest,
 936                       struct ref **sought, int nr_sought,
 937                       char **pack_lockfile)
 938{
 939        struct stat st;
 940        struct ref *ref_cpy;
 941
 942        fetch_pack_setup();
 943        if (args->depth > 0) {
 944                if (stat(git_path("shallow"), &st))
 945                        st.st_mtime = 0;
 946        }
 947
 948        if (nr_sought)
 949                nr_sought = remove_duplicates_in_refs(sought, nr_sought);
 950
 951        if (!ref) {
 952                packet_flush(fd[1]);
 953                die("no matching remote head");
 954        }
 955        ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought, pack_lockfile);
 956
 957        if (args->depth > 0) {
 958                static struct lock_file lock;
 959                struct cache_time mtime;
 960                struct strbuf sb = STRBUF_INIT;
 961                char *shallow = git_path("shallow");
 962                int fd;
 963
 964                mtime.sec = st.st_mtime;
 965                mtime.nsec = ST_MTIME_NSEC(st);
 966                if (stat(shallow, &st)) {
 967                        if (mtime.sec)
 968                                die("shallow file was removed during fetch");
 969                } else if (st.st_mtime != mtime.sec
 970#ifdef USE_NSEC
 971                                || ST_MTIME_NSEC(st) != mtime.nsec
 972#endif
 973                          )
 974                        die("shallow file was changed during fetch");
 975
 976                fd = hold_lock_file_for_update(&lock, shallow,
 977                                               LOCK_DIE_ON_ERROR);
 978                if (!write_shallow_commits(&sb, 0)
 979                 || write_in_full(fd, sb.buf, sb.len) != sb.len) {
 980                        unlink_or_warn(shallow);
 981                        rollback_lock_file(&lock);
 982                } else {
 983                        commit_lock_file(&lock);
 984                }
 985                strbuf_release(&sb);
 986        }
 987
 988        reprepare_packed_git();
 989        return ref_cpy;
 990}