fetch-pack.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "pkt-line.h"
   4 #include "commit.h"
   5 #include "tag.h"
   6 #include "exec_cmd.h"
   7 #include "pack.h"
   8 #include "sideband.h"
   9 #include "fetch-pack.h"
  10 #include "remote.h"
  11 #include "run-command.h"
  12 #include "connect.h"
  13 #include "transport.h"
  14 #include "version.h"
  15 #include "prio-queue.h"
  16 #include "sha1-array.h"
  17
  18 static int transfer_unpack_limit = -1;
  19 static int fetch_unpack_limit = -1;
  20 static int unpack_limit = 100;
  21 static int prefer_ofs_delta = 1;
  22 static int no_done;
  23 static int fetch_fsck_objects = -1;
  24 static int transfer_fsck_objects = -1;
  25 static int agent_supported;
  26 static struct lock_file shallow_lock;
  27 static const char *alternate_shallow_file;
  28
  29 /* Remember to update object flag allocation in object.h */
  30 #define COMPLETE        (1U << 0)
  31 #define COMMON          (1U << 1)
  32 #define COMMON_REF      (1U << 2)
  33 #define SEEN            (1U << 3)
  34 #define POPPED          (1U << 4)
  35
  36 static int marked;
  37
  38 /*
  39  * After sending this many "have"s if we do not get any new ACK , we
  40  * give up traversing our history.
  41  */
  42 #define MAX_IN_VAIN 256
  43
  44 static struct prio_queue rev_list = { compare_commits_by_commit_date };
  45 static int non_common_revs, multi_ack, use_sideband, allow_tip_sha1_in_want;
  46
  47 static void rev_list_push(struct commit *commit, int mark)
  48 {
  49         if (!(commit->object.flags & mark)) {
  50                 commit->object.flags |= mark;
  51
  52                 if (parse_commit(commit))
  53                         return;
  54
  55                 prio_queue_put(&rev_list, commit);
  56
  57                 if (!(commit->object.flags & COMMON))
  58                         non_common_revs++;
  59         }
  60 }
  61
  62 static int rev_list_insert_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
  63 {
  64         struct object *o = deref_tag(parse_object(sha1), refname, 0);
  65
  66         if (o && o->type == OBJ_COMMIT)
  67                 rev_list_push((struct commit *)o, SEEN);
  68
  69         return 0;
  70 }
  71
  72 static int clear_marks(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
  73 {
  74         struct object *o = deref_tag(parse_object(sha1), refname, 0);
  75
  76         if (o && o->type == OBJ_COMMIT)
  77                 clear_commit_marks((struct commit *)o,
  78                                    COMMON | COMMON_REF | SEEN | POPPED);
  79         return 0;
  80 }
  81
  82 /*
  83    This function marks a rev and its ancestors as common.
  84    In some cases, it is desirable to mark only the ancestors (for example
  85    when only the server does not yet know that they are common).
  86 */
  87
  88 static void mark_common(struct commit *commit,
  89                 int ancestors_only, int dont_parse)
  90 {
  91         if (commit != NULL && !(commit->object.flags & COMMON)) {
  92                 struct object *o = (struct object *)commit;
  93
  94                 if (!ancestors_only)
  95                         o->flags |= COMMON;
  96
  97                 if (!(o->flags & SEEN))
  98                         rev_list_push(commit, SEEN);
  99                 else {
 100                         struct commit_list *parents;
 101
 102                         if (!ancestors_only && !(o->flags & POPPED))
 103                                 non_common_revs--;
 104                         if (!o->parsed && !dont_parse)
 105                                 if (parse_commit(commit))
 106                                         return;
 107
 108                         for (parents = commit->parents;
 109                                         parents;
 110                                         parents = parents->next)
 111                                 mark_common(parents->item, 0, dont_parse);
 112                 }
 113         }
 114 }
 115
 116 /*
 117   Get the next rev to send, ignoring the common.
 118 */
 119
 120 static const unsigned char *get_rev(void)
 121 {
 122         struct commit *commit = NULL;
 123
 124         while (commit == NULL) {
 125                 unsigned int mark;
 126                 struct commit_list *parents;
 127
 128                 if (rev_list.nr == 0 || non_common_revs == 0)
 129                         return NULL;
 130
 131                 commit = prio_queue_get(&rev_list);
 132                 parse_commit(commit);
 133                 parents = commit->parents;
 134
 135                 commit->object.flags |= POPPED;
 136                 if (!(commit->object.flags & COMMON))
 137                         non_common_revs--;
 138
 139                 if (commit->object.flags & COMMON) {
 140                         /* do not send "have", and ignore ancestors */
 141                         commit = NULL;
 142                         mark = COMMON | SEEN;
 143                 } else if (commit->object.flags & COMMON_REF)
 144                         /* send "have", and ignore ancestors */
 145                         mark = COMMON | SEEN;
 146                 else
 147                         /* send "have", also for its ancestors */
 148                         mark = SEEN;
 149
 150                 while (parents) {
 151                         if (!(parents->item->object.flags & SEEN))
 152                                 rev_list_push(parents->item, mark);
 153                         if (mark & COMMON)
 154                                 mark_common(parents->item, 1, 0);
 155                         parents = parents->next;
 156                 }
 157         }
 158
 159         return commit->object.sha1;
 160 }
 161
 162 enum ack_type {
 163         NAK = 0,
 164         ACK,
 165         ACK_continue,
 166         ACK_common,
 167         ACK_ready
 168 };
 169
 170 static void consume_shallow_list(struct fetch_pack_args *args, int fd)
 171 {
 172         if (args->stateless_rpc && args->depth > 0) {
 173                 /* If we sent a depth we will get back "duplicate"
 174                  * shallow and unshallow commands every time there
 175                  * is a block of have lines exchanged.
 176                  */
 177                 char *line;
 178                 while ((line = packet_read_line(fd, NULL))) {
 179                         if (starts_with(line, "shallow "))
 180                                 continue;
 181                         if (starts_with(line, "unshallow "))
 182                                 continue;
 183                         die("git fetch-pack: expected shallow list");
 184                 }
 185         }
 186 }
 187
 188 static enum ack_type get_ack(int fd, unsigned char *result_sha1)
 189 {
 190         int len;
 191         char *line = packet_read_line(fd, &len);
 192
 193         if (!len)
 194                 die("git fetch-pack: expected ACK/NAK, got EOF");
 195         if (!strcmp(line, "NAK"))
 196                 return NAK;
 197         if (starts_with(line, "ACK ")) {
 198                 if (!get_sha1_hex(line+4, result_sha1)) {
 199                         if (len < 45)
 200                                 return ACK;
 201                         if (strstr(line+45, "continue"))
 202                                 return ACK_continue;
 203                         if (strstr(line+45, "common"))
 204                                 return ACK_common;
 205                         if (strstr(line+45, "ready"))
 206                                 return ACK_ready;
 207                         return ACK;
 208                 }
 209         }
 210         die("git fetch_pack: expected ACK/NAK, got '%s'", line);
 211 }
 212
 213 static void send_request(struct fetch_pack_args *args,
 214                          int fd, struct strbuf *buf)
 215 {
 216         if (args->stateless_rpc) {
 217                 send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 218                 packet_flush(fd);
 219         } else
 220                 write_or_die(fd, buf->buf, buf->len);
 221 }
 222
 223 static void insert_one_alternate_ref(const struct ref *ref, void *unused)
 224 {
 225         rev_list_insert_ref(NULL, ref->old_sha1, 0, NULL);
 226 }
 227
 228 #define INITIAL_FLUSH 16
 229 #define PIPESAFE_FLUSH 32
 230 #define LARGE_FLUSH 1024
 231
 232 static int next_flush(struct fetch_pack_args *args, int count)
 233 {
 234         int flush_limit = args->stateless_rpc ? LARGE_FLUSH : PIPESAFE_FLUSH;
 235
 236         if (count < flush_limit)
 237                 count <<= 1;
 238         else
 239                 count += flush_limit;
 240         return count;
 241 }
 242
 243 static int find_common(struct fetch_pack_args *args,
 244                        int fd[2], unsigned char *result_sha1,
 245                        struct ref *refs)
 246 {
 247         int fetching;
 248         int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 249         const unsigned char *sha1;
 250         unsigned in_vain = 0;
 251         int got_continue = 0;
 252         int got_ready = 0;
 253         struct strbuf req_buf = STRBUF_INIT;
 254         size_t state_len = 0;
 255
 256         if (args->stateless_rpc && multi_ack == 1)
 257                 die("--stateless-rpc requires multi_ack_detailed");
 258         if (marked)
 259                 for_each_ref(clear_marks, NULL);
 260         marked = 1;
 261
 262         for_each_ref(rev_list_insert_ref, NULL);
 263         for_each_alternate_ref(insert_one_alternate_ref, NULL);
 264
 265         fetching = 0;
 266         for ( ; refs ; refs = refs->next) {
 267                 unsigned char *remote = refs->old_sha1;
 268                 const char *remote_hex;
 269                 struct object *o;
 270
 271                 /*
 272                  * If that object is complete (i.e. it is an ancestor of a
 273                  * local ref), we tell them we have it but do not have to
 274                  * tell them about its ancestors, which they already know
 275                  * about.
 276                  *
 277                  * We use lookup_object here because we are only
 278                  * interested in the case we *know* the object is
 279                  * reachable and we have already scanned it.
 280                  */
 281                 if (((o = lookup_object(remote)) != NULL) &&
 282                                 (o->flags & COMPLETE)) {
 283                         continue;
 284                 }
 285
 286                 remote_hex = sha1_to_hex(remote);
 287                 if (!fetching) {
 288                         struct strbuf c = STRBUF_INIT;
 289                         if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 290                         if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 291                         if (no_done)            strbuf_addstr(&c, " no-done");
 292                         if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 293                         if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 294                         if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
 295                         if (args->no_progress)   strbuf_addstr(&c, " no-progress");
 296                         if (args->include_tag)   strbuf_addstr(&c, " include-tag");
 297                         if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 298                         if (agent_supported)    strbuf_addf(&c, " agent=%s",
 299                                                             git_user_agent_sanitized());
 300                         packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 301                         strbuf_release(&c);
 302                 } else
 303                         packet_buf_write(&req_buf, "want %s\n", remote_hex);
 304                 fetching++;
 305         }
 306
 307         if (!fetching) {
 308                 strbuf_release(&req_buf);
 309                 packet_flush(fd[1]);
 310                 return 1;
 311         }
 312
 313         if (is_repository_shallow())
 314                 write_shallow_commits(&req_buf, 1, NULL);
 315         if (args->depth > 0)
 316                 packet_buf_write(&req_buf, "deepen %d", args->depth);
 317         packet_buf_flush(&req_buf);
 318         state_len = req_buf.len;
 319
 320         if (args->depth > 0) {
 321                 char *line;
 322                 unsigned char sha1[20];
 323
 324                 send_request(args, fd[1], &req_buf);
 325                 while ((line = packet_read_line(fd[0], NULL))) {
 326                         if (starts_with(line, "shallow ")) {
 327                                 if (get_sha1_hex(line + 8, sha1))
 328                                         die("invalid shallow line: %s", line);
 329                                 register_shallow(sha1);
 330                                 continue;
 331                         }
 332                         if (starts_with(line, "unshallow ")) {
 333                                 if (get_sha1_hex(line + 10, sha1))
 334                                         die("invalid unshallow line: %s", line);
 335                                 if (!lookup_object(sha1))
 336                                         die("object not found: %s", line);
 337                                 /* make sure that it is parsed as shallow */
 338                                 if (!parse_object(sha1))
 339                                         die("error in object: %s", line);
 340                                 if (unregister_shallow(sha1))
 341                                         die("no shallow found: %s", line);
 342                                 continue;
 343                         }
 344                         die("expected shallow/unshallow, got %s", line);
 345                 }
 346         } else if (!args->stateless_rpc)
 347                 send_request(args, fd[1], &req_buf);
 348
 349         if (!args->stateless_rpc) {
 350                 /* If we aren't using the stateless-rpc interface
 351                  * we don't need to retain the headers.
 352                  */
 353                 strbuf_setlen(&req_buf, 0);
 354                 state_len = 0;
 355         }
 356
 357         flushes = 0;
 358         retval = -1;
 359         while ((sha1 = get_rev())) {
 360                 packet_buf_write(&req_buf, "have %s\n", sha1_to_hex(sha1));
 361                 if (args->verbose)
 362                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
 363                 in_vain++;
 364                 if (flush_at <= ++count) {
 365                         int ack;
 366
 367                         packet_buf_flush(&req_buf);
 368                         send_request(args, fd[1], &req_buf);
 369                         strbuf_setlen(&req_buf, state_len);
 370                         flushes++;
 371                         flush_at = next_flush(args, count);
 372
 373                         /*
 374                          * We keep one window "ahead" of the other side, and
 375                          * will wait for an ACK only on the next one
 376                          */
 377                         if (!args->stateless_rpc && count == INITIAL_FLUSH)
 378                                 continue;
 379
 380                         consume_shallow_list(args, fd[0]);
 381                         do {
 382                                 ack = get_ack(fd[0], result_sha1);
 383                                 if (args->verbose && ack)
 384                                         fprintf(stderr, "got ack %d %s\n", ack,
 385                                                         sha1_to_hex(result_sha1));
 386                                 switch (ack) {
 387                                 case ACK:
 388                                         flushes = 0;
 389                                         multi_ack = 0;
 390                                         retval = 0;
 391                                         goto done;
 392                                 case ACK_common:
 393                                 case ACK_ready:
 394                                 case ACK_continue: {
 395                                         struct commit *commit =
 396                                                 lookup_commit(result_sha1);
 397                                         if (!commit)
 398                                                 die("invalid commit %s", sha1_to_hex(result_sha1));
 399                                         if (args->stateless_rpc
 400                                          && ack == ACK_common
 401                                          && !(commit->object.flags & COMMON)) {
 402                                                 /* We need to replay the have for this object
 403                                                  * on the next RPC request so the peer knows
 404                                                  * it is in common with us.
 405                                                  */
 406                                                 const char *hex = sha1_to_hex(result_sha1);
 407                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 408                                                 state_len = req_buf.len;
 409                                         }
 410                                         mark_common(commit, 0, 1);
 411                                         retval = 0;
 412                                         in_vain = 0;
 413                                         got_continue = 1;
 414                                         if (ack == ACK_ready) {
 415                                                 clear_prio_queue(&rev_list);
 416                                                 got_ready = 1;
 417                                         }
 418                                         break;
 419                                         }
 420                                 }
 421                         } while (ack);
 422                         flushes--;
 423                         if (got_continue && MAX_IN_VAIN < in_vain) {
 424                                 if (args->verbose)
 425                                         fprintf(stderr, "giving up\n");
 426                                 break; /* give up */
 427                         }
 428                 }
 429         }
 430 done:
 431         if (!got_ready || !no_done) {
 432                 packet_buf_write(&req_buf, "done\n");
 433                 send_request(args, fd[1], &req_buf);
 434         }
 435         if (args->verbose)
 436                 fprintf(stderr, "done\n");
 437         if (retval != 0) {
 438                 multi_ack = 0;
 439                 flushes++;
 440         }
 441         strbuf_release(&req_buf);
 442
 443         if (!got_ready || !no_done)
 444                 consume_shallow_list(args, fd[0]);
 445         while (flushes || multi_ack) {
 446                 int ack = get_ack(fd[0], result_sha1);
 447                 if (ack) {
 448                         if (args->verbose)
 449                                 fprintf(stderr, "got ack (%d) %s\n", ack,
 450                                         sha1_to_hex(result_sha1));
 451                         if (ack == ACK)
 452                                 return 0;
 453                         multi_ack = 1;
 454                         continue;
 455                 }
 456                 flushes--;
 457         }
 458         /* it is no error to fetch into a completely empty repo */
 459         return count ? retval : 0;
 460 }
 461
 462 static struct commit_list *complete;
 463
 464 static int mark_complete(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
 465 {
 466         struct object *o = parse_object(sha1);
 467
 468         while (o && o->type == OBJ_TAG) {
 469                 struct tag *t = (struct tag *) o;
 470                 if (!t->tagged)
 471                         break; /* broken repository */
 472                 o->flags |= COMPLETE;
 473                 o = parse_object(t->tagged->sha1);
 474         }
 475         if (o && o->type == OBJ_COMMIT) {
 476                 struct commit *commit = (struct commit *)o;
 477                 if (!(commit->object.flags & COMPLETE)) {
 478                         commit->object.flags |= COMPLETE;
 479                         commit_list_insert(commit, &complete);
 480                 }
 481         }
 482         return 0;
 483 }
 484
 485 static void mark_recent_complete_commits(struct fetch_pack_args *args,
 486                                          unsigned long cutoff)
 487 {
 488         while (complete && cutoff <= complete->item->date) {
 489                 if (args->verbose)
 490                         fprintf(stderr, "Marking %s as complete\n",
 491                                 sha1_to_hex(complete->item->object.sha1));
 492                 pop_most_recent_commit(&complete, COMPLETE);
 493         }
 494 }
 495
 496 static void filter_refs(struct fetch_pack_args *args,
 497                         struct ref **refs,
 498                         struct ref **sought, int nr_sought)
 499 {
 500         struct ref *newlist = NULL;
 501         struct ref **newtail = &newlist;
 502         struct ref *ref, *next;
 503         int i;
 504
 505         i = 0;
 506         for (ref = *refs; ref; ref = next) {
 507                 int keep = 0;
 508                 next = ref->next;
 509
 510                 if (!memcmp(ref->name, "refs/", 5) &&
 511                     check_refname_format(ref->name, 0))
 512                         ; /* trash */
 513                 else {
 514                         while (i < nr_sought) {
 515                                 int cmp = strcmp(ref->name, sought[i]->name);
 516                                 if (cmp < 0)
 517                                         break; /* definitely do not have it */
 518                                 else if (cmp == 0) {
 519                                         keep = 1; /* definitely have it */
 520                                         sought[i]->matched = 1;
 521                                 }
 522                                 i++;
 523                         }
 524                 }
 525
 526                 if (!keep && args->fetch_all &&
 527                     (!args->depth || !starts_with(ref->name, "refs/tags/")))
 528                         keep = 1;
 529
 530                 if (keep) {
 531                         *newtail = ref;
 532                         ref->next = NULL;
 533                         newtail = &ref->next;
 534                 } else {
 535                         free(ref);
 536                 }
 537         }
 538
 539         /* Append unmatched requests to the list */
 540         if (allow_tip_sha1_in_want) {
 541                 for (i = 0; i < nr_sought; i++) {
 542                         ref = sought[i];
 543                         if (ref->matched)
 544                                 continue;
 545                         if (get_sha1_hex(ref->name, ref->old_sha1))
 546                                 continue;
 547
 548                         ref->matched = 1;
 549                         *newtail = ref;
 550                         ref->next = NULL;
 551                         newtail = &ref->next;
 552                 }
 553         }
 554         *refs = newlist;
 555 }
 556
 557 static void mark_alternate_complete(const struct ref *ref, void *unused)
 558 {
 559         mark_complete(NULL, ref->old_sha1, 0, NULL);
 560 }
 561
 562 static int everything_local(struct fetch_pack_args *args,
 563                             struct ref **refs,
 564                             struct ref **sought, int nr_sought)
 565 {
 566         struct ref *ref;
 567         int retval;
 568         unsigned long cutoff = 0;
 569
 570         save_commit_buffer = 0;
 571
 572         for (ref = *refs; ref; ref = ref->next) {
 573                 struct object *o;
 574
 575                 if (!has_sha1_file(ref->old_sha1))
 576                         continue;
 577
 578                 o = parse_object(ref->old_sha1);
 579                 if (!o)
 580                         continue;
 581
 582                 /* We already have it -- which may mean that we were
 583                  * in sync with the other side at some time after
 584                  * that (it is OK if we guess wrong here).
 585                  */
 586                 if (o->type == OBJ_COMMIT) {
 587                         struct commit *commit = (struct commit *)o;
 588                         if (!cutoff || cutoff < commit->date)
 589                                 cutoff = commit->date;
 590                 }
 591         }
 592
 593         if (!args->depth) {
 594                 for_each_ref(mark_complete, NULL);
 595                 for_each_alternate_ref(mark_alternate_complete, NULL);
 596                 commit_list_sort_by_date(&complete);
 597                 if (cutoff)
 598                         mark_recent_complete_commits(args, cutoff);
 599         }
 600
 601         /*
 602          * Mark all complete remote refs as common refs.
 603          * Don't mark them common yet; the server has to be told so first.
 604          */
 605         for (ref = *refs; ref; ref = ref->next) {
 606                 struct object *o = deref_tag(lookup_object(ref->old_sha1),
 607                                              NULL, 0);
 608
 609                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 610                         continue;
 611
 612                 if (!(o->flags & SEEN)) {
 613                         rev_list_push((struct commit *)o, COMMON_REF | SEEN);
 614
 615                         mark_common((struct commit *)o, 1, 1);
 616                 }
 617         }
 618
 619         filter_refs(args, refs, sought, nr_sought);
 620
 621         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 622                 const unsigned char *remote = ref->old_sha1;
 623                 unsigned char local[20];
 624                 struct object *o;
 625
 626                 o = lookup_object(remote);
 627                 if (!o || !(o->flags & COMPLETE)) {
 628                         retval = 0;
 629                         if (!args->verbose)
 630                                 continue;
 631                         fprintf(stderr,
 632                                 "want %s (%s)\n", sha1_to_hex(remote),
 633                                 ref->name);
 634                         continue;
 635                 }
 636
 637                 hashcpy(ref->new_sha1, local);
 638                 if (!args->verbose)
 639                         continue;
 640                 fprintf(stderr,
 641                         "already have %s (%s)\n", sha1_to_hex(remote),
 642                         ref->name);
 643         }
 644         return retval;
 645 }
 646
 647 static int sideband_demux(int in, int out, void *data)
 648 {
 649         int *xd = data;
 650
 651         int ret = recv_sideband("fetch-pack", xd[0], out);
 652         close(out);
 653         return ret;
 654 }
 655
 656 static int get_pack(struct fetch_pack_args *args,
 657                     int xd[2], char **pack_lockfile)
 658 {
 659         struct async demux;
 660         const char *argv[22];
 661         char keep_arg[256];
 662         char hdr_arg[256];
 663         const char **av, *cmd_name;
 664         int do_keep = args->keep_pack;
 665         struct child_process cmd;
 666         int ret;
 667
 668         memset(&demux, 0, sizeof(demux));
 669         if (use_sideband) {
 670                 /* xd[] is talking with upload-pack; subprocess reads from
 671                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 672                  * through demux->out.
 673                  */
 674                 demux.proc = sideband_demux;
 675                 demux.data = xd;
 676                 demux.out = -1;
 677                 if (start_async(&demux))
 678                         die("fetch-pack: unable to fork off sideband"
 679                             " demultiplexer");
 680         }
 681         else
 682                 demux.out = xd[0];
 683
 684         memset(&cmd, 0, sizeof(cmd));
 685         cmd.argv = argv;
 686         av = argv;
 687         *hdr_arg = 0;
 688         if (!args->keep_pack && unpack_limit) {
 689                 struct pack_header header;
 690
 691                 if (read_pack_header(demux.out, &header))
 692                         die("protocol error: bad pack header");
 693                 snprintf(hdr_arg, sizeof(hdr_arg),
 694                          "--pack_header=%"PRIu32",%"PRIu32,
 695                          ntohl(header.hdr_version), ntohl(header.hdr_entries));
 696                 if (ntohl(header.hdr_entries) < unpack_limit)
 697                         do_keep = 0;
 698                 else
 699                         do_keep = 1;
 700         }
 701
 702         if (alternate_shallow_file) {
 703                 *av++ = "--shallow-file";
 704                 *av++ = alternate_shallow_file;
 705         }
 706
 707         if (do_keep) {
 708                 if (pack_lockfile)
 709                         cmd.out = -1;
 710                 *av++ = cmd_name = "index-pack";
 711                 *av++ = "--stdin";
 712                 if (!args->quiet && !args->no_progress)
 713                         *av++ = "-v";
 714                 if (args->use_thin_pack)
 715                         *av++ = "--fix-thin";
 716                 if (args->lock_pack || unpack_limit) {
 717                         int s = sprintf(keep_arg,
 718                                         "--keep=fetch-pack %"PRIuMAX " on ", (uintmax_t) getpid());
 719                         if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
 720                                 strcpy(keep_arg + s, "localhost");
 721                         *av++ = keep_arg;
 722                 }
 723                 if (args->check_self_contained_and_connected)
 724                         *av++ = "--check-self-contained-and-connected";
 725         }
 726         else {
 727                 *av++ = cmd_name = "unpack-objects";
 728                 if (args->quiet || args->no_progress)
 729                         *av++ = "-q";
 730                 args->check_self_contained_and_connected = 0;
 731         }
 732         if (*hdr_arg)
 733                 *av++ = hdr_arg;
 734         if (fetch_fsck_objects >= 0
 735             ? fetch_fsck_objects
 736             : transfer_fsck_objects >= 0
 737             ? transfer_fsck_objects
 738             : 0)
 739                 *av++ = "--strict";
 740         *av++ = NULL;
 741
 742         cmd.in = demux.out;
 743         cmd.git_cmd = 1;
 744         if (start_command(&cmd))
 745                 die("fetch-pack: unable to fork off %s", cmd_name);
 746         if (do_keep && pack_lockfile) {
 747                 *pack_lockfile = index_pack_lockfile(cmd.out);
 748                 close(cmd.out);
 749         }
 750
 751         if (!use_sideband)
 752                 /* Closed by start_command() */
 753                 xd[0] = -1;
 754
 755         ret = finish_command(&cmd);
 756         if (!ret || (args->check_self_contained_and_connected && ret == 1))
 757                 args->self_contained_and_connected =
 758                         args->check_self_contained_and_connected &&
 759                         ret == 0;
 760         else
 761                 die("%s failed", cmd_name);
 762         if (use_sideband && finish_async(&demux))
 763                 die("error in sideband demultiplexer");
 764         return 0;
 765 }
 766
 767 static int cmp_ref_by_name(const void *a_, const void *b_)
 768 {
 769         const struct ref *a = *((const struct ref **)a_);
 770         const struct ref *b = *((const struct ref **)b_);
 771         return strcmp(a->name, b->name);
 772 }
 773
 774 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 775                                  int fd[2],
 776                                  const struct ref *orig_ref,
 777                                  struct ref **sought, int nr_sought,
 778                                  struct shallow_info *si,
 779                                  char **pack_lockfile)
 780 {
 781         struct ref *ref = copy_ref_list(orig_ref);
 782         unsigned char sha1[20];
 783         const char *agent_feature;
 784         int agent_len;
 785
 786         sort_ref_list(&ref, ref_compare_name);
 787         qsort(sought, nr_sought, sizeof(*sought), cmp_ref_by_name);
 788
 789         if (is_repository_shallow() && !server_supports("shallow"))
 790                 die("Server does not support shallow clients");
 791         if (server_supports("multi_ack_detailed")) {
 792                 if (args->verbose)
 793                         fprintf(stderr, "Server supports multi_ack_detailed\n");
 794                 multi_ack = 2;
 795                 if (server_supports("no-done")) {
 796                         if (args->verbose)
 797                                 fprintf(stderr, "Server supports no-done\n");
 798                         if (args->stateless_rpc)
 799                                 no_done = 1;
 800                 }
 801         }
 802         else if (server_supports("multi_ack")) {
 803                 if (args->verbose)
 804                         fprintf(stderr, "Server supports multi_ack\n");
 805                 multi_ack = 1;
 806         }
 807         if (server_supports("side-band-64k")) {
 808                 if (args->verbose)
 809                         fprintf(stderr, "Server supports side-band-64k\n");
 810                 use_sideband = 2;
 811         }
 812         else if (server_supports("side-band")) {
 813                 if (args->verbose)
 814                         fprintf(stderr, "Server supports side-band\n");
 815                 use_sideband = 1;
 816         }
 817         if (server_supports("allow-tip-sha1-in-want")) {
 818                 if (args->verbose)
 819                         fprintf(stderr, "Server supports allow-tip-sha1-in-want\n");
 820                 allow_tip_sha1_in_want = 1;
 821         }
 822         if (!server_supports("thin-pack"))
 823                 args->use_thin_pack = 0;
 824         if (!server_supports("no-progress"))
 825                 args->no_progress = 0;
 826         if (!server_supports("include-tag"))
 827                 args->include_tag = 0;
 828         if (server_supports("ofs-delta")) {
 829                 if (args->verbose)
 830                         fprintf(stderr, "Server supports ofs-delta\n");
 831         } else
 832                 prefer_ofs_delta = 0;
 833
 834         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 835                 agent_supported = 1;
 836                 if (args->verbose && agent_len)
 837                         fprintf(stderr, "Server version is %.*s\n",
 838                                 agent_len, agent_feature);
 839         }
 840
 841         if (everything_local(args, &ref, sought, nr_sought)) {
 842                 packet_flush(fd[1]);
 843                 goto all_done;
 844         }
 845         if (find_common(args, fd, sha1, ref) < 0)
 846                 if (!args->keep_pack)
 847                         /* When cloning, it is not unusual to have
 848                          * no common commit.
 849                          */
 850                         warning("no common commits");
 851
 852         if (args->stateless_rpc)
 853                 packet_flush(fd[1]);
 854         if (args->depth > 0)
 855                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
 856                                         NULL);
 857         else if (si->nr_ours || si->nr_theirs)
 858                 alternate_shallow_file = setup_temporary_shallow(si->shallow);
 859         else
 860                 alternate_shallow_file = NULL;
 861         if (get_pack(args, fd, pack_lockfile))
 862                 die("git fetch-pack: fetch failed.");
 863
 864  all_done:
 865         return ref;
 866 }
 867
 868 static 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
 898 static 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
 911 static 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
 932 static void update_shallow(struct fetch_pack_args *args,
 933                            struct ref **sought, int nr_sought,
 934                            struct shallow_info *si)
 935 {
 936         struct sha1_array ref = SHA1_ARRAY_INIT;
 937         int *status;
 938         int i;
 939
 940         if (args->depth > 0 && alternate_shallow_file) {
 941                 if (*alternate_shallow_file == '\0') { /* --unshallow */
 942                         unlink_or_warn(git_path("shallow"));
 943                         rollback_lock_file(&shallow_lock);
 944                 } else
 945                         commit_lock_file(&shallow_lock);
 946                 return;
 947         }
 948
 949         if (!si->shallow || !si->shallow->nr)
 950                 return;
 951
 952         if (args->cloning) {
 953                 /*
 954                  * remote is shallow, but this is a clone, there are
 955                  * no objects in repo to worry about. Accept any
 956                  * shallow points that exist in the pack (iow in repo
 957                  * after get_pack() and reprepare_packed_git())
 958                  */
 959                 struct sha1_array extra = SHA1_ARRAY_INIT;
 960                 unsigned char (*sha1)[20] = si->shallow->sha1;
 961                 for (i = 0; i < si->shallow->nr; i++)
 962                         if (has_sha1_file(sha1[i]))
 963                                 sha1_array_append(&extra, sha1[i]);
 964                 if (extra.nr) {
 965                         setup_alternate_shallow(&shallow_lock,
 966                                                 &alternate_shallow_file,
 967                                                 &extra);
 968                         commit_lock_file(&shallow_lock);
 969                 }
 970                 sha1_array_clear(&extra);
 971                 return;
 972         }
 973
 974         if (!si->nr_ours && !si->nr_theirs)
 975                 return;
 976
 977         remove_nonexistent_theirs_shallow(si);
 978         if (!si->nr_ours && !si->nr_theirs)
 979                 return;
 980         for (i = 0; i < nr_sought; i++)
 981                 sha1_array_append(&ref, sought[i]->old_sha1);
 982         si->ref = &ref;
 983
 984         if (args->update_shallow) {
 985                 /*
 986                  * remote is also shallow, .git/shallow may be updated
 987                  * so all refs can be accepted. Make sure we only add
 988                  * shallow roots that are actually reachable from new
 989                  * refs.
 990                  */
 991                 struct sha1_array extra = SHA1_ARRAY_INIT;
 992                 unsigned char (*sha1)[20] = si->shallow->sha1;
 993                 assign_shallow_commits_to_refs(si, NULL, NULL);
 994                 if (!si->nr_ours && !si->nr_theirs) {
 995                         sha1_array_clear(&ref);
 996                         return;
 997                 }
 998                 for (i = 0; i < si->nr_ours; i++)
 999                         sha1_array_append(&extra, sha1[si->ours[i]]);
1000                 for (i = 0; i < si->nr_theirs; i++)
1001                         sha1_array_append(&extra, sha1[si->theirs[i]]);
1002                 setup_alternate_shallow(&shallow_lock,
1003                                         &alternate_shallow_file,
1004                                         &extra);
1005                 commit_lock_file(&shallow_lock);
1006                 sha1_array_clear(&extra);
1007                 sha1_array_clear(&ref);
1008                 return;
1009         }
1010
1011         /*
1012          * remote is also shallow, check what ref is safe to update
1013          * without updating .git/shallow
1014          */
1015         status = xcalloc(nr_sought, sizeof(*status));
1016         assign_shallow_commits_to_refs(si, NULL, status);
1017         if (si->nr_ours || si->nr_theirs) {
1018                 for (i = 0; i < nr_sought; i++)
1019                         if (status[i])
1020                                 sought[i]->status = REF_STATUS_REJECT_SHALLOW;
1021         }
1022         free(status);
1023         sha1_array_clear(&ref);
1024 }
1025
1026 struct ref *fetch_pack(struct fetch_pack_args *args,
1027                        int fd[], struct child_process *conn,
1028                        const struct ref *ref,
1029                        const char *dest,
1030                        struct ref **sought, int nr_sought,
1031                        struct sha1_array *shallow,
1032                        char **pack_lockfile)
1033 {
1034         struct ref *ref_cpy;
1035         struct shallow_info si;
1036
1037         fetch_pack_setup();
1038         if (nr_sought)
1039                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
1040
1041         if (!ref) {
1042                 packet_flush(fd[1]);
1043                 die("no matching remote head");
1044         }
1045         prepare_shallow_info(&si, shallow);
1046         ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
1047                                 &si, pack_lockfile);
1048         reprepare_packed_git();
1049         update_shallow(args, sought, nr_sought, &si);
1050         clear_shallow_info(&si);
1051         return ref_cpy;
1052 }