git.oblomov.eu Git - git/blob - fetch-pack.c

   1 #include "cache.h"
   2 #include "repository.h"
   3 #include "config.h"
   4 #include "lockfile.h"
   5 #include "refs.h"
   6 #include "pkt-line.h"
   7 #include "commit.h"
   8 #include "tag.h"
   9 #include "exec-cmd.h"
  10 #include "pack.h"
  11 #include "sideband.h"
  12 #include "fetch-pack.h"
  13 #include "remote.h"
  14 #include "run-command.h"
  15 #include "connect.h"
  16 #include "transport.h"
  17 #include "version.h"
  18 #include "sha1-array.h"
  19 #include "oidset.h"
  20 #include "packfile.h"
  21 #include "object-store.h"
  22 #include "connected.h"
  23 #include "fetch-negotiator.h"
  24 #include "fsck.h"
  25
  26 static int transfer_unpack_limit = -1;
  27 static int fetch_unpack_limit = -1;
  28 static int unpack_limit = 100;
  29 static int prefer_ofs_delta = 1;
  30 static int no_done;
  31 static int deepen_since_ok;
  32 static int deepen_not_ok;
  33 static int fetch_fsck_objects = -1;
  34 static int transfer_fsck_objects = -1;
  35 static int agent_supported;
  36 static int server_supports_filtering;
  37 static struct lock_file shallow_lock;
  38 static const char *alternate_shallow_file;
  39 static char *negotiation_algorithm;
  40 static struct strbuf fsck_msg_types = STRBUF_INIT;
  41
  42 /* Remember to update object flag allocation in object.h */
  43 #define COMPLETE        (1U << 0)
  44 #define ALTERNATE       (1U << 1)
  45
  46 /*
  47  * After sending this many "have"s if we do not get any new ACK , we
  48  * give up traversing our history.
  49  */
  50 #define MAX_IN_VAIN 256
  51
  52 static int multi_ack, use_sideband;
  53 /* Allow specifying sha1 if it is a ref tip. */
  54 #define ALLOW_TIP_SHA1  01
  55 /* Allow request of a sha1 if it is reachable from a ref (possibly hidden ref). */
  56 #define ALLOW_REACHABLE_SHA1    02
  57 static unsigned int allow_unadvertised_object_request;
  58
  59 __attribute__((format (printf, 2, 3)))
  60 static inline void print_verbose(const struct fetch_pack_args *args,
  61                                  const char *fmt, ...)
  62 {
  63         va_list params;
  64
  65         if (!args->verbose)
  66                 return;
  67
  68         va_start(params, fmt);
  69         vfprintf(stderr, fmt, params);
  70         va_end(params);
  71         fputc('\n', stderr);
  72 }
  73
  74 struct alternate_object_cache {
  75         struct object **items;
  76         size_t nr, alloc;
  77 };
  78
  79 static void cache_one_alternate(const struct object_id *oid,
  80                                 void *vcache)
  81 {
  82         struct alternate_object_cache *cache = vcache;
  83         struct object *obj = parse_object(the_repository, oid);
  84
  85         if (!obj || (obj->flags & ALTERNATE))
  86                 return;
  87
  88         obj->flags |= ALTERNATE;
  89         ALLOC_GROW(cache->items, cache->nr + 1, cache->alloc);
  90         cache->items[cache->nr++] = obj;
  91 }
  92
  93 static void for_each_cached_alternate(struct fetch_negotiator *negotiator,
  94                                       void (*cb)(struct fetch_negotiator *,
  95                                                  struct object *))
  96 {
  97         static int initialized;
  98         static struct alternate_object_cache cache;
  99         size_t i;
 100
 101         if (!initialized) {
 102                 for_each_alternate_ref(cache_one_alternate, &cache);
 103                 initialized = 1;
 104         }
 105
 106         for (i = 0; i < cache.nr; i++)
 107                 cb(negotiator, cache.items[i]);
 108 }
 109
 110 static int rev_list_insert_ref(struct fetch_negotiator *negotiator,
 111                                const char *refname,
 112                                const struct object_id *oid)
 113 {
 114         struct object *o = deref_tag(the_repository,
 115                                      parse_object(the_repository, oid),
 116                                      refname, 0);
 117
 118         if (o && o->type == OBJ_COMMIT)
 119                 negotiator->add_tip(negotiator, (struct commit *)o);
 120
 121         return 0;
 122 }
 123
 124 static int rev_list_insert_ref_oid(const char *refname, const struct object_id *oid,
 125                                    int flag, void *cb_data)
 126 {
 127         return rev_list_insert_ref(cb_data, refname, oid);
 128 }
 129
 130 enum ack_type {
 131         NAK = 0,
 132         ACK,
 133         ACK_continue,
 134         ACK_common,
 135         ACK_ready
 136 };
 137
 138 static void consume_shallow_list(struct fetch_pack_args *args,
 139                                  struct packet_reader *reader)
 140 {
 141         if (args->stateless_rpc && args->deepen) {
 142                 /* If we sent a depth we will get back "duplicate"
 143                  * shallow and unshallow commands every time there
 144                  * is a block of have lines exchanged.
 145                  */
 146                 while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 147                         if (starts_with(reader->line, "shallow "))
 148                                 continue;
 149                         if (starts_with(reader->line, "unshallow "))
 150                                 continue;
 151                         die(_("git fetch-pack: expected shallow list"));
 152                 }
 153                 if (reader->status != PACKET_READ_FLUSH)
 154                         die(_("git fetch-pack: expected a flush packet after shallow list"));
 155         }
 156 }
 157
 158 static enum ack_type get_ack(struct packet_reader *reader,
 159                              struct object_id *result_oid)
 160 {
 161         int len;
 162         const char *arg;
 163
 164         if (packet_reader_read(reader) != PACKET_READ_NORMAL)
 165                 die(_("git fetch-pack: expected ACK/NAK, got a flush packet"));
 166         len = reader->pktlen;
 167
 168         if (!strcmp(reader->line, "NAK"))
 169                 return NAK;
 170         if (skip_prefix(reader->line, "ACK ", &arg)) {
 171                 if (!get_oid_hex(arg, result_oid)) {
 172                         arg += 40;
 173                         len -= arg - reader->line;
 174                         if (len < 1)
 175                                 return ACK;
 176                         if (strstr(arg, "continue"))
 177                                 return ACK_continue;
 178                         if (strstr(arg, "common"))
 179                                 return ACK_common;
 180                         if (strstr(arg, "ready"))
 181                                 return ACK_ready;
 182                         return ACK;
 183                 }
 184         }
 185         die(_("git fetch-pack: expected ACK/NAK, got '%s'"), reader->line);
 186 }
 187
 188 static void send_request(struct fetch_pack_args *args,
 189                          int fd, struct strbuf *buf)
 190 {
 191         if (args->stateless_rpc) {
 192                 send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 193                 packet_flush(fd);
 194         } else {
 195                 if (write_in_full(fd, buf->buf, buf->len) < 0)
 196                         die_errno(_("unable to write to remote"));
 197         }
 198 }
 199
 200 static void insert_one_alternate_object(struct fetch_negotiator *negotiator,
 201                                         struct object *obj)
 202 {
 203         rev_list_insert_ref(negotiator, NULL, &obj->oid);
 204 }
 205
 206 #define INITIAL_FLUSH 16
 207 #define PIPESAFE_FLUSH 32
 208 #define LARGE_FLUSH 16384
 209
 210 static int next_flush(int stateless_rpc, int count)
 211 {
 212         if (stateless_rpc) {
 213                 if (count < LARGE_FLUSH)
 214                         count <<= 1;
 215                 else
 216                         count = count * 11 / 10;
 217         } else {
 218                 if (count < PIPESAFE_FLUSH)
 219                         count <<= 1;
 220                 else
 221                         count += PIPESAFE_FLUSH;
 222         }
 223         return count;
 224 }
 225
 226 static void mark_tips(struct fetch_negotiator *negotiator,
 227                       const struct oid_array *negotiation_tips)
 228 {
 229         int i;
 230
 231         if (!negotiation_tips) {
 232                 for_each_ref(rev_list_insert_ref_oid, negotiator);
 233                 return;
 234         }
 235
 236         for (i = 0; i < negotiation_tips->nr; i++)
 237                 rev_list_insert_ref(negotiator, NULL,
 238                                     &negotiation_tips->oid[i]);
 239         return;
 240 }
 241
 242 static int find_common(struct fetch_negotiator *negotiator,
 243                        struct fetch_pack_args *args,
 244                        int fd[2], struct object_id *result_oid,
 245                        struct ref *refs)
 246 {
 247         int fetching;
 248         int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 249         const struct object_id *oid;
 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         struct packet_reader reader;
 256
 257         if (args->stateless_rpc && multi_ack == 1)
 258                 die(_("--stateless-rpc requires multi_ack_detailed"));
 259
 260         packet_reader_init(&reader, fd[0], NULL, 0,
 261                            PACKET_READ_CHOMP_NEWLINE |
 262                            PACKET_READ_DIE_ON_ERR_PACKET);
 263
 264         if (!args->no_dependents) {
 265                 mark_tips(negotiator, args->negotiation_tips);
 266                 for_each_cached_alternate(negotiator, insert_one_alternate_object);
 267         }
 268
 269         fetching = 0;
 270         for ( ; refs ; refs = refs->next) {
 271                 struct object_id *remote = &refs->old_oid;
 272                 const char *remote_hex;
 273                 struct object *o;
 274
 275                 /*
 276                  * If that object is complete (i.e. it is an ancestor of a
 277                  * local ref), we tell them we have it but do not have to
 278                  * tell them about its ancestors, which they already know
 279                  * about.
 280                  *
 281                  * We use lookup_object here because we are only
 282                  * interested in the case we *know* the object is
 283                  * reachable and we have already scanned it.
 284                  *
 285                  * Do this only if args->no_dependents is false (if it is true,
 286                  * we cannot trust the object flags).
 287                  */
 288                 if (!args->no_dependents &&
 289                     ((o = lookup_object(the_repository, remote->hash)) != NULL) &&
 290                                 (o->flags & COMPLETE)) {
 291                         continue;
 292                 }
 293
 294                 remote_hex = oid_to_hex(remote);
 295                 if (!fetching) {
 296                         struct strbuf c = STRBUF_INIT;
 297                         if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 298                         if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 299                         if (no_done)            strbuf_addstr(&c, " no-done");
 300                         if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 301                         if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 302                         if (args->deepen_relative) strbuf_addstr(&c, " deepen-relative");
 303                         if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
 304                         if (args->no_progress)   strbuf_addstr(&c, " no-progress");
 305                         if (args->include_tag)   strbuf_addstr(&c, " include-tag");
 306                         if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 307                         if (deepen_since_ok)    strbuf_addstr(&c, " deepen-since");
 308                         if (deepen_not_ok)      strbuf_addstr(&c, " deepen-not");
 309                         if (agent_supported)    strbuf_addf(&c, " agent=%s",
 310                                                             git_user_agent_sanitized());
 311                         if (args->filter_options.choice)
 312                                 strbuf_addstr(&c, " filter");
 313                         packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 314                         strbuf_release(&c);
 315                 } else
 316                         packet_buf_write(&req_buf, "want %s\n", remote_hex);
 317                 fetching++;
 318         }
 319
 320         if (!fetching) {
 321                 strbuf_release(&req_buf);
 322                 packet_flush(fd[1]);
 323                 return 1;
 324         }
 325
 326         if (is_repository_shallow(the_repository))
 327                 write_shallow_commits(&req_buf, 1, NULL);
 328         if (args->depth > 0)
 329                 packet_buf_write(&req_buf, "deepen %d", args->depth);
 330         if (args->deepen_since) {
 331                 timestamp_t max_age = approxidate(args->deepen_since);
 332                 packet_buf_write(&req_buf, "deepen-since %"PRItime, max_age);
 333         }
 334         if (args->deepen_not) {
 335                 int i;
 336                 for (i = 0; i < args->deepen_not->nr; i++) {
 337                         struct string_list_item *s = args->deepen_not->items + i;
 338                         packet_buf_write(&req_buf, "deepen-not %s", s->string);
 339                 }
 340         }
 341         if (server_supports_filtering && args->filter_options.choice) {
 342                 const char *spec =
 343                         expand_list_objects_filter_spec(&args->filter_options);
 344                 packet_buf_write(&req_buf, "filter %s", spec);
 345         }
 346         packet_buf_flush(&req_buf);
 347         state_len = req_buf.len;
 348
 349         if (args->deepen) {
 350                 const char *arg;
 351                 struct object_id oid;
 352
 353                 send_request(args, fd[1], &req_buf);
 354                 while (packet_reader_read(&reader) == PACKET_READ_NORMAL) {
 355                         if (skip_prefix(reader.line, "shallow ", &arg)) {
 356                                 if (get_oid_hex(arg, &oid))
 357                                         die(_("invalid shallow line: %s"), reader.line);
 358                                 register_shallow(the_repository, &oid);
 359                                 continue;
 360                         }
 361                         if (skip_prefix(reader.line, "unshallow ", &arg)) {
 362                                 if (get_oid_hex(arg, &oid))
 363                                         die(_("invalid unshallow line: %s"), reader.line);
 364                                 if (!lookup_object(the_repository, oid.hash))
 365                                         die(_("object not found: %s"), reader.line);
 366                                 /* make sure that it is parsed as shallow */
 367                                 if (!parse_object(the_repository, &oid))
 368                                         die(_("error in object: %s"), reader.line);
 369                                 if (unregister_shallow(&oid))
 370                                         die(_("no shallow found: %s"), reader.line);
 371                                 continue;
 372                         }
 373                         die(_("expected shallow/unshallow, got %s"), reader.line);
 374                 }
 375         } else if (!args->stateless_rpc)
 376                 send_request(args, fd[1], &req_buf);
 377
 378         if (!args->stateless_rpc) {
 379                 /* If we aren't using the stateless-rpc interface
 380                  * we don't need to retain the headers.
 381                  */
 382                 strbuf_setlen(&req_buf, 0);
 383                 state_len = 0;
 384         }
 385
 386         flushes = 0;
 387         retval = -1;
 388         if (args->no_dependents)
 389                 goto done;
 390         while ((oid = negotiator->next(negotiator))) {
 391                 packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid));
 392                 print_verbose(args, "have %s", oid_to_hex(oid));
 393                 in_vain++;
 394                 if (flush_at <= ++count) {
 395                         int ack;
 396
 397                         packet_buf_flush(&req_buf);
 398                         send_request(args, fd[1], &req_buf);
 399                         strbuf_setlen(&req_buf, state_len);
 400                         flushes++;
 401                         flush_at = next_flush(args->stateless_rpc, count);
 402
 403                         /*
 404                          * We keep one window "ahead" of the other side, and
 405                          * will wait for an ACK only on the next one
 406                          */
 407                         if (!args->stateless_rpc && count == INITIAL_FLUSH)
 408                                 continue;
 409
 410                         consume_shallow_list(args, &reader);
 411                         do {
 412                                 ack = get_ack(&reader, result_oid);
 413                                 if (ack)
 414                                         print_verbose(args, _("got %s %d %s"), "ack",
 415                                                       ack, oid_to_hex(result_oid));
 416                                 switch (ack) {
 417                                 case ACK:
 418                                         flushes = 0;
 419                                         multi_ack = 0;
 420                                         retval = 0;
 421                                         goto done;
 422                                 case ACK_common:
 423                                 case ACK_ready:
 424                                 case ACK_continue: {
 425                                         struct commit *commit =
 426                                                 lookup_commit(the_repository,
 427                                                               result_oid);
 428                                         int was_common;
 429
 430                                         if (!commit)
 431                                                 die(_("invalid commit %s"), oid_to_hex(result_oid));
 432                                         was_common = negotiator->ack(negotiator, commit);
 433                                         if (args->stateless_rpc
 434                                          && ack == ACK_common
 435                                          && !was_common) {
 436                                                 /* We need to replay the have for this object
 437                                                  * on the next RPC request so the peer knows
 438                                                  * it is in common with us.
 439                                                  */
 440                                                 const char *hex = oid_to_hex(result_oid);
 441                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 442                                                 state_len = req_buf.len;
 443                                                 /*
 444                                                  * Reset in_vain because an ack
 445                                                  * for this commit has not been
 446                                                  * seen.
 447                                                  */
 448                                                 in_vain = 0;
 449                                         } else if (!args->stateless_rpc
 450                                                    || ack != ACK_common)
 451                                                 in_vain = 0;
 452                                         retval = 0;
 453                                         got_continue = 1;
 454                                         if (ack == ACK_ready)
 455                                                 got_ready = 1;
 456                                         break;
 457                                         }
 458                                 }
 459                         } while (ack);
 460                         flushes--;
 461                         if (got_continue && MAX_IN_VAIN < in_vain) {
 462                                 print_verbose(args, _("giving up"));
 463                                 break; /* give up */
 464                         }
 465                         if (got_ready)
 466                                 break;
 467                 }
 468         }
 469 done:
 470         if (!got_ready || !no_done) {
 471                 packet_buf_write(&req_buf, "done\n");
 472                 send_request(args, fd[1], &req_buf);
 473         }
 474         print_verbose(args, _("done"));
 475         if (retval != 0) {
 476                 multi_ack = 0;
 477                 flushes++;
 478         }
 479         strbuf_release(&req_buf);
 480
 481         if (!got_ready || !no_done)
 482                 consume_shallow_list(args, &reader);
 483         while (flushes || multi_ack) {
 484                 int ack = get_ack(&reader, result_oid);
 485                 if (ack) {
 486                         print_verbose(args, _("got %s (%d) %s"), "ack",
 487                                       ack, oid_to_hex(result_oid));
 488                         if (ack == ACK)
 489                                 return 0;
 490                         multi_ack = 1;
 491                         continue;
 492                 }
 493                 flushes--;
 494         }
 495         /* it is no error to fetch into a completely empty repo */
 496         return count ? retval : 0;
 497 }
 498
 499 static struct commit_list *complete;
 500
 501 static int mark_complete(const struct object_id *oid)
 502 {
 503         struct object *o = parse_object(the_repository, oid);
 504
 505         while (o && o->type == OBJ_TAG) {
 506                 struct tag *t = (struct tag *) o;
 507                 if (!t->tagged)
 508                         break; /* broken repository */
 509                 o->flags |= COMPLETE;
 510                 o = parse_object(the_repository, &t->tagged->oid);
 511         }
 512         if (o && o->type == OBJ_COMMIT) {
 513                 struct commit *commit = (struct commit *)o;
 514                 if (!(commit->object.flags & COMPLETE)) {
 515                         commit->object.flags |= COMPLETE;
 516                         commit_list_insert(commit, &complete);
 517                 }
 518         }
 519         return 0;
 520 }
 521
 522 static int mark_complete_oid(const char *refname, const struct object_id *oid,
 523                              int flag, void *cb_data)
 524 {
 525         return mark_complete(oid);
 526 }
 527
 528 static void mark_recent_complete_commits(struct fetch_pack_args *args,
 529                                          timestamp_t cutoff)
 530 {
 531         while (complete && cutoff <= complete->item->date) {
 532                 print_verbose(args, _("Marking %s as complete"),
 533                               oid_to_hex(&complete->item->object.oid));
 534                 pop_most_recent_commit(&complete, COMPLETE);
 535         }
 536 }
 537
 538 static void add_refs_to_oidset(struct oidset *oids, struct ref *refs)
 539 {
 540         for (; refs; refs = refs->next)
 541                 oidset_insert(oids, &refs->old_oid);
 542 }
 543
 544 static int is_unmatched_ref(const struct ref *ref)
 545 {
 546         struct object_id oid;
 547         const char *p;
 548         return  ref->match_status == REF_NOT_MATCHED &&
 549                 !parse_oid_hex(ref->name, &oid, &p) &&
 550                 *p == '\0' &&
 551                 oideq(&oid, &ref->old_oid);
 552 }
 553
 554 static void filter_refs(struct fetch_pack_args *args,
 555                         struct ref **refs,
 556                         struct ref **sought, int nr_sought)
 557 {
 558         struct ref *newlist = NULL;
 559         struct ref **newtail = &newlist;
 560         struct ref *unmatched = NULL;
 561         struct ref *ref, *next;
 562         struct oidset tip_oids = OIDSET_INIT;
 563         int i;
 564         int strict = !(allow_unadvertised_object_request &
 565                        (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1));
 566
 567         i = 0;
 568         for (ref = *refs; ref; ref = next) {
 569                 int keep = 0;
 570                 next = ref->next;
 571
 572                 if (starts_with(ref->name, "refs/") &&
 573                     check_refname_format(ref->name, 0)) {
 574                         /*
 575                          * trash or a peeled value; do not even add it to
 576                          * unmatched list
 577                          */
 578                         free_one_ref(ref);
 579                         continue;
 580                 } else {
 581                         while (i < nr_sought) {
 582                                 int cmp = strcmp(ref->name, sought[i]->name);
 583                                 if (cmp < 0)
 584                                         break; /* definitely do not have it */
 585                                 else if (cmp == 0) {
 586                                         keep = 1; /* definitely have it */
 587                                         sought[i]->match_status = REF_MATCHED;
 588                                 }
 589                                 i++;
 590                         }
 591
 592                         if (!keep && args->fetch_all &&
 593                             (!args->deepen || !starts_with(ref->name, "refs/tags/")))
 594                                 keep = 1;
 595                 }
 596
 597                 if (keep) {
 598                         *newtail = ref;
 599                         ref->next = NULL;
 600                         newtail = &ref->next;
 601                 } else {
 602                         ref->next = unmatched;
 603                         unmatched = ref;
 604                 }
 605         }
 606
 607         if (strict) {
 608                 for (i = 0; i < nr_sought; i++) {
 609                         ref = sought[i];
 610                         if (!is_unmatched_ref(ref))
 611                                 continue;
 612
 613                         add_refs_to_oidset(&tip_oids, unmatched);
 614                         add_refs_to_oidset(&tip_oids, newlist);
 615                         break;
 616                 }
 617         }
 618
 619         /* Append unmatched requests to the list */
 620         for (i = 0; i < nr_sought; i++) {
 621                 ref = sought[i];
 622                 if (!is_unmatched_ref(ref))
 623                         continue;
 624
 625                 if (!strict || oidset_contains(&tip_oids, &ref->old_oid)) {
 626                         ref->match_status = REF_MATCHED;
 627                         *newtail = copy_ref(ref);
 628                         newtail = &(*newtail)->next;
 629                 } else {
 630                         ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
 631                 }
 632         }
 633
 634         oidset_clear(&tip_oids);
 635         free_refs(unmatched);
 636
 637         *refs = newlist;
 638 }
 639
 640 static void mark_alternate_complete(struct fetch_negotiator *unused,
 641                                     struct object *obj)
 642 {
 643         mark_complete(&obj->oid);
 644 }
 645
 646 struct loose_object_iter {
 647         struct oidset *loose_object_set;
 648         struct ref *refs;
 649 };
 650
 651 /*
 652  * Mark recent commits available locally and reachable from a local ref as
 653  * COMPLETE. If args->no_dependents is false, also mark COMPLETE remote refs as
 654  * COMMON_REF (otherwise, we are not planning to participate in negotiation, and
 655  * thus do not need COMMON_REF marks).
 656  *
 657  * The cutoff time for recency is determined by this heuristic: it is the
 658  * earliest commit time of the objects in refs that are commits and that we know
 659  * the commit time of.
 660  */
 661 static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
 662                                          struct fetch_pack_args *args,
 663                                          struct ref **refs)
 664 {
 665         struct ref *ref;
 666         int old_save_commit_buffer = save_commit_buffer;
 667         timestamp_t cutoff = 0;
 668
 669         save_commit_buffer = 0;
 670
 671         for (ref = *refs; ref; ref = ref->next) {
 672                 struct object *o;
 673
 674                 if (!has_object_file_with_flags(&ref->old_oid,
 675                                                 OBJECT_INFO_QUICK))
 676                         continue;
 677                 o = parse_object(the_repository, &ref->old_oid);
 678                 if (!o)
 679                         continue;
 680
 681                 /* We already have it -- which may mean that we were
 682                  * in sync with the other side at some time after
 683                  * that (it is OK if we guess wrong here).
 684                  */
 685                 if (o->type == OBJ_COMMIT) {
 686                         struct commit *commit = (struct commit *)o;
 687                         if (!cutoff || cutoff < commit->date)
 688                                 cutoff = commit->date;
 689                 }
 690         }
 691
 692         if (!args->deepen) {
 693                 for_each_ref(mark_complete_oid, NULL);
 694                 for_each_cached_alternate(NULL, mark_alternate_complete);
 695                 commit_list_sort_by_date(&complete);
 696                 if (cutoff)
 697                         mark_recent_complete_commits(args, cutoff);
 698         }
 699
 700         /*
 701          * Mark all complete remote refs as common refs.
 702          * Don't mark them common yet; the server has to be told so first.
 703          */
 704         for (ref = *refs; ref; ref = ref->next) {
 705                 struct object *o = deref_tag(the_repository,
 706                                              lookup_object(the_repository,
 707                                              ref->old_oid.hash),
 708                                              NULL, 0);
 709
 710                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 711                         continue;
 712
 713                 negotiator->known_common(negotiator,
 714                                          (struct commit *)o);
 715         }
 716
 717         save_commit_buffer = old_save_commit_buffer;
 718 }
 719
 720 /*
 721  * Returns 1 if every object pointed to by the given remote refs is available
 722  * locally and reachable from a local ref, and 0 otherwise.
 723  */
 724 static int everything_local(struct fetch_pack_args *args,
 725                             struct ref **refs)
 726 {
 727         struct ref *ref;
 728         int retval;
 729
 730         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 731                 const struct object_id *remote = &ref->old_oid;
 732                 struct object *o;
 733
 734                 o = lookup_object(the_repository, remote->hash);
 735                 if (!o || !(o->flags & COMPLETE)) {
 736                         retval = 0;
 737                         print_verbose(args, "want %s (%s)", oid_to_hex(remote),
 738                                       ref->name);
 739                         continue;
 740                 }
 741                 print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
 742                               ref->name);
 743         }
 744
 745         return retval;
 746 }
 747
 748 static int sideband_demux(int in, int out, void *data)
 749 {
 750         int *xd = data;
 751         int ret;
 752
 753         ret = recv_sideband("fetch-pack", xd[0], out);
 754         close(out);
 755         return ret;
 756 }
 757
 758 static int get_pack(struct fetch_pack_args *args,
 759                     int xd[2], char **pack_lockfile)
 760 {
 761         struct async demux;
 762         int do_keep = args->keep_pack;
 763         const char *cmd_name;
 764         struct pack_header header;
 765         int pass_header = 0;
 766         struct child_process cmd = CHILD_PROCESS_INIT;
 767         int ret;
 768
 769         memset(&demux, 0, sizeof(demux));
 770         if (use_sideband) {
 771                 /* xd[] is talking with upload-pack; subprocess reads from
 772                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 773                  * through demux->out.
 774                  */
 775                 demux.proc = sideband_demux;
 776                 demux.data = xd;
 777                 demux.out = -1;
 778                 demux.isolate_sigpipe = 1;
 779                 if (start_async(&demux))
 780                         die(_("fetch-pack: unable to fork off sideband demultiplexer"));
 781         }
 782         else
 783                 demux.out = xd[0];
 784
 785         if (!args->keep_pack && unpack_limit) {
 786
 787                 if (read_pack_header(demux.out, &header))
 788                         die(_("protocol error: bad pack header"));
 789                 pass_header = 1;
 790                 if (ntohl(header.hdr_entries) < unpack_limit)
 791                         do_keep = 0;
 792                 else
 793                         do_keep = 1;
 794         }
 795
 796         if (alternate_shallow_file) {
 797                 argv_array_push(&cmd.args, "--shallow-file");
 798                 argv_array_push(&cmd.args, alternate_shallow_file);
 799         }
 800
 801         if (do_keep || args->from_promisor) {
 802                 if (pack_lockfile)
 803                         cmd.out = -1;
 804                 cmd_name = "index-pack";
 805                 argv_array_push(&cmd.args, cmd_name);
 806                 argv_array_push(&cmd.args, "--stdin");
 807                 if (!args->quiet && !args->no_progress)
 808                         argv_array_push(&cmd.args, "-v");
 809                 if (args->use_thin_pack)
 810                         argv_array_push(&cmd.args, "--fix-thin");
 811                 if (do_keep && (args->lock_pack || unpack_limit)) {
 812                         char hostname[HOST_NAME_MAX + 1];
 813                         if (xgethostname(hostname, sizeof(hostname)))
 814                                 xsnprintf(hostname, sizeof(hostname), "localhost");
 815                         argv_array_pushf(&cmd.args,
 816                                         "--keep=fetch-pack %"PRIuMAX " on %s",
 817                                         (uintmax_t)getpid(), hostname);
 818                 }
 819                 if (args->check_self_contained_and_connected)
 820                         argv_array_push(&cmd.args, "--check-self-contained-and-connected");
 821                 if (args->from_promisor)
 822                         argv_array_push(&cmd.args, "--promisor");
 823         }
 824         else {
 825                 cmd_name = "unpack-objects";
 826                 argv_array_push(&cmd.args, cmd_name);
 827                 if (args->quiet || args->no_progress)
 828                         argv_array_push(&cmd.args, "-q");
 829                 args->check_self_contained_and_connected = 0;
 830         }
 831
 832         if (pass_header)
 833                 argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
 834                                  ntohl(header.hdr_version),
 835                                  ntohl(header.hdr_entries));
 836         if (fetch_fsck_objects >= 0
 837             ? fetch_fsck_objects
 838             : transfer_fsck_objects >= 0
 839             ? transfer_fsck_objects
 840             : 0) {
 841                 if (args->from_promisor)
 842                         /*
 843                          * We cannot use --strict in index-pack because it
 844                          * checks both broken objects and links, but we only
 845                          * want to check for broken objects.
 846                          */
 847                         argv_array_push(&cmd.args, "--fsck-objects");
 848                 else
 849                         argv_array_pushf(&cmd.args, "--strict%s",
 850                                          fsck_msg_types.buf);
 851         }
 852
 853         cmd.in = demux.out;
 854         cmd.git_cmd = 1;
 855         if (start_command(&cmd))
 856                 die(_("fetch-pack: unable to fork off %s"), cmd_name);
 857         if (do_keep && pack_lockfile) {
 858                 *pack_lockfile = index_pack_lockfile(cmd.out);
 859                 close(cmd.out);
 860         }
 861
 862         if (!use_sideband)
 863                 /* Closed by start_command() */
 864                 xd[0] = -1;
 865
 866         ret = finish_command(&cmd);
 867         if (!ret || (args->check_self_contained_and_connected && ret == 1))
 868                 args->self_contained_and_connected =
 869                         args->check_self_contained_and_connected &&
 870                         ret == 0;
 871         else
 872                 die(_("%s failed"), cmd_name);
 873         if (use_sideband && finish_async(&demux))
 874                 die(_("error in sideband demultiplexer"));
 875         return 0;
 876 }
 877
 878 static int cmp_ref_by_name(const void *a_, const void *b_)
 879 {
 880         const struct ref *a = *((const struct ref **)a_);
 881         const struct ref *b = *((const struct ref **)b_);
 882         return strcmp(a->name, b->name);
 883 }
 884
 885 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 886                                  int fd[2],
 887                                  const struct ref *orig_ref,
 888                                  struct ref **sought, int nr_sought,
 889                                  struct shallow_info *si,
 890                                  char **pack_lockfile)
 891 {
 892         struct ref *ref = copy_ref_list(orig_ref);
 893         struct object_id oid;
 894         const char *agent_feature;
 895         int agent_len;
 896         struct fetch_negotiator negotiator;
 897         fetch_negotiator_init(&negotiator, negotiation_algorithm);
 898
 899         sort_ref_list(&ref, ref_compare_name);
 900         QSORT(sought, nr_sought, cmp_ref_by_name);
 901
 902         if ((args->depth > 0 || is_repository_shallow(the_repository)) && !server_supports("shallow"))
 903                 die(_("Server does not support shallow clients"));
 904         if (args->depth > 0 || args->deepen_since || args->deepen_not)
 905                 args->deepen = 1;
 906         if (server_supports("multi_ack_detailed")) {
 907                 print_verbose(args, _("Server supports multi_ack_detailed"));
 908                 multi_ack = 2;
 909                 if (server_supports("no-done")) {
 910                         print_verbose(args, _("Server supports no-done"));
 911                         if (args->stateless_rpc)
 912                                 no_done = 1;
 913                 }
 914         }
 915         else if (server_supports("multi_ack")) {
 916                 print_verbose(args, _("Server supports multi_ack"));
 917                 multi_ack = 1;
 918         }
 919         if (server_supports("side-band-64k")) {
 920                 print_verbose(args, _("Server supports side-band-64k"));
 921                 use_sideband = 2;
 922         }
 923         else if (server_supports("side-band")) {
 924                 print_verbose(args, _("Server supports side-band"));
 925                 use_sideband = 1;
 926         }
 927         if (server_supports("allow-tip-sha1-in-want")) {
 928                 print_verbose(args, _("Server supports allow-tip-sha1-in-want"));
 929                 allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
 930         }
 931         if (server_supports("allow-reachable-sha1-in-want")) {
 932                 print_verbose(args, _("Server supports allow-reachable-sha1-in-want"));
 933                 allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
 934         }
 935         if (!server_supports("thin-pack"))
 936                 args->use_thin_pack = 0;
 937         if (!server_supports("no-progress"))
 938                 args->no_progress = 0;
 939         if (!server_supports("include-tag"))
 940                 args->include_tag = 0;
 941         if (server_supports("ofs-delta"))
 942                 print_verbose(args, _("Server supports ofs-delta"));
 943         else
 944                 prefer_ofs_delta = 0;
 945
 946         if (server_supports("filter")) {
 947                 server_supports_filtering = 1;
 948                 print_verbose(args, _("Server supports filter"));
 949         } else if (args->filter_options.choice) {
 950                 warning("filtering not recognized by server, ignoring");
 951         }
 952
 953         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 954                 agent_supported = 1;
 955                 if (agent_len)
 956                         print_verbose(args, _("Server version is %.*s"),
 957                                       agent_len, agent_feature);
 958         }
 959         if (server_supports("deepen-since"))
 960                 deepen_since_ok = 1;
 961         else if (args->deepen_since)
 962                 die(_("Server does not support --shallow-since"));
 963         if (server_supports("deepen-not"))
 964                 deepen_not_ok = 1;
 965         else if (args->deepen_not)
 966                 die(_("Server does not support --shallow-exclude"));
 967         if (!server_supports("deepen-relative") && args->deepen_relative)
 968                 die(_("Server does not support --deepen"));
 969
 970         if (!args->no_dependents) {
 971                 mark_complete_and_common_ref(&negotiator, args, &ref);
 972                 filter_refs(args, &ref, sought, nr_sought);
 973                 if (everything_local(args, &ref)) {
 974                         packet_flush(fd[1]);
 975                         goto all_done;
 976                 }
 977         } else {
 978                 filter_refs(args, &ref, sought, nr_sought);
 979         }
 980         if (find_common(&negotiator, args, fd, &oid, ref) < 0)
 981                 if (!args->keep_pack)
 982                         /* When cloning, it is not unusual to have
 983                          * no common commit.
 984                          */
 985                         warning(_("no common commits"));
 986
 987         if (args->stateless_rpc)
 988                 packet_flush(fd[1]);
 989         if (args->deepen)
 990                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
 991                                         NULL);
 992         else if (si->nr_ours || si->nr_theirs)
 993                 alternate_shallow_file = setup_temporary_shallow(si->shallow);
 994         else
 995                 alternate_shallow_file = NULL;
 996         if (get_pack(args, fd, pack_lockfile))
 997                 die(_("git fetch-pack: fetch failed."));
 998
 999  all_done:
1000         negotiator.release(&negotiator);
1001         return ref;
1002 }
1003
1004 static void add_shallow_requests(struct strbuf *req_buf,
1005                                  const struct fetch_pack_args *args)
1006 {
1007         if (is_repository_shallow(the_repository))
1008                 write_shallow_commits(req_buf, 1, NULL);
1009         if (args->depth > 0)
1010                 packet_buf_write(req_buf, "deepen %d", args->depth);
1011         if (args->deepen_since) {
1012                 timestamp_t max_age = approxidate(args->deepen_since);
1013                 packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
1014         }
1015         if (args->deepen_not) {
1016                 int i;
1017                 for (i = 0; i < args->deepen_not->nr; i++) {
1018                         struct string_list_item *s = args->deepen_not->items + i;
1019                         packet_buf_write(req_buf, "deepen-not %s", s->string);
1020                 }
1021         }
1022         if (args->deepen_relative)
1023                 packet_buf_write(req_buf, "deepen-relative\n");
1024 }
1025
1026 static void add_wants(int no_dependents, const struct ref *wants, struct strbuf *req_buf)
1027 {
1028         int use_ref_in_want = server_supports_feature("fetch", "ref-in-want", 0);
1029
1030         for ( ; wants ; wants = wants->next) {
1031                 const struct object_id *remote = &wants->old_oid;
1032                 struct object *o;
1033
1034                 /*
1035                  * If that object is complete (i.e. it is an ancestor of a
1036                  * local ref), we tell them we have it but do not have to
1037                  * tell them about its ancestors, which they already know
1038                  * about.
1039                  *
1040                  * We use lookup_object here because we are only
1041                  * interested in the case we *know* the object is
1042                  * reachable and we have already scanned it.
1043                  *
1044                  * Do this only if args->no_dependents is false (if it is true,
1045                  * we cannot trust the object flags).
1046                  */
1047                 if (!no_dependents &&
1048                     ((o = lookup_object(the_repository, remote->hash)) != NULL) &&
1049                     (o->flags & COMPLETE)) {
1050                         continue;
1051                 }
1052
1053                 if (!use_ref_in_want || wants->exact_oid)
1054                         packet_buf_write(req_buf, "want %s\n", oid_to_hex(remote));
1055                 else
1056                         packet_buf_write(req_buf, "want-ref %s\n", wants->name);
1057         }
1058 }
1059
1060 static void add_common(struct strbuf *req_buf, struct oidset *common)
1061 {
1062         struct oidset_iter iter;
1063         const struct object_id *oid;
1064         oidset_iter_init(common, &iter);
1065
1066         while ((oid = oidset_iter_next(&iter))) {
1067                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1068         }
1069 }
1070
1071 static int add_haves(struct fetch_negotiator *negotiator,
1072                      struct strbuf *req_buf,
1073                      int *haves_to_send, int *in_vain)
1074 {
1075         int ret = 0;
1076         int haves_added = 0;
1077         const struct object_id *oid;
1078
1079         while ((oid = negotiator->next(negotiator))) {
1080                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1081                 if (++haves_added >= *haves_to_send)
1082                         break;
1083         }
1084
1085         *in_vain += haves_added;
1086         if (!haves_added || *in_vain >= MAX_IN_VAIN) {
1087                 /* Send Done */
1088                 packet_buf_write(req_buf, "done\n");
1089                 ret = 1;
1090         }
1091
1092         /* Increase haves to send on next round */
1093         *haves_to_send = next_flush(1, *haves_to_send);
1094
1095         return ret;
1096 }
1097
1098 static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
1099                               struct fetch_pack_args *args,
1100                               const struct ref *wants, struct oidset *common,
1101                               int *haves_to_send, int *in_vain,
1102                               int sideband_all)
1103 {
1104         int ret = 0;
1105         struct strbuf req_buf = STRBUF_INIT;
1106
1107         if (server_supports_v2("fetch", 1))
1108                 packet_buf_write(&req_buf, "command=fetch");
1109         if (server_supports_v2("agent", 0))
1110                 packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
1111         if (args->server_options && args->server_options->nr &&
1112             server_supports_v2("server-option", 1)) {
1113                 int i;
1114                 for (i = 0; i < args->server_options->nr; i++)
1115                         packet_buf_write(&req_buf, "server-option=%s",
1116                                          args->server_options->items[i].string);
1117         }
1118
1119         packet_buf_delim(&req_buf);
1120         if (args->use_thin_pack)
1121                 packet_buf_write(&req_buf, "thin-pack");
1122         if (args->no_progress)
1123                 packet_buf_write(&req_buf, "no-progress");
1124         if (args->include_tag)
1125                 packet_buf_write(&req_buf, "include-tag");
1126         if (prefer_ofs_delta)
1127                 packet_buf_write(&req_buf, "ofs-delta");
1128         if (sideband_all)
1129                 packet_buf_write(&req_buf, "sideband-all");
1130
1131         /* Add shallow-info and deepen request */
1132         if (server_supports_feature("fetch", "shallow", 0))
1133                 add_shallow_requests(&req_buf, args);
1134         else if (is_repository_shallow(the_repository) || args->deepen)
1135                 die(_("Server does not support shallow requests"));
1136
1137         /* Add filter */
1138         if (server_supports_feature("fetch", "filter", 0) &&
1139             args->filter_options.choice) {
1140                 const char *spec =
1141                         expand_list_objects_filter_spec(&args->filter_options);
1142                 print_verbose(args, _("Server supports filter"));
1143                 packet_buf_write(&req_buf, "filter %s", spec);
1144         } else if (args->filter_options.choice) {
1145                 warning("filtering not recognized by server, ignoring");
1146         }
1147
1148         /* add wants */
1149         add_wants(args->no_dependents, wants, &req_buf);
1150
1151         if (args->no_dependents) {
1152                 packet_buf_write(&req_buf, "done");
1153                 ret = 1;
1154         } else {
1155                 /* Add all of the common commits we've found in previous rounds */
1156                 add_common(&req_buf, common);
1157
1158                 /* Add initial haves */
1159                 ret = add_haves(negotiator, &req_buf, haves_to_send, in_vain);
1160         }
1161
1162         /* Send request */
1163         packet_buf_flush(&req_buf);
1164         if (write_in_full(fd_out, req_buf.buf, req_buf.len) < 0)
1165                 die_errno(_("unable to write request to remote"));
1166
1167         strbuf_release(&req_buf);
1168         return ret;
1169 }
1170
1171 /*
1172  * Processes a section header in a server's response and checks if it matches
1173  * `section`.  If the value of `peek` is 1, the header line will be peeked (and
1174  * not consumed); if 0, the line will be consumed and the function will die if
1175  * the section header doesn't match what was expected.
1176  */
1177 static int process_section_header(struct packet_reader *reader,
1178                                   const char *section, int peek)
1179 {
1180         int ret;
1181
1182         if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
1183                 die(_("error reading section header '%s'"), section);
1184
1185         ret = !strcmp(reader->line, section);
1186
1187         if (!peek) {
1188                 if (!ret)
1189                         die(_("expected '%s', received '%s'"),
1190                             section, reader->line);
1191                 packet_reader_read(reader);
1192         }
1193
1194         return ret;
1195 }
1196
1197 static int process_acks(struct fetch_negotiator *negotiator,
1198                         struct packet_reader *reader,
1199                         struct oidset *common)
1200 {
1201         /* received */
1202         int received_ready = 0;
1203         int received_ack = 0;
1204
1205         process_section_header(reader, "acknowledgments", 0);
1206         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1207                 const char *arg;
1208
1209                 if (!strcmp(reader->line, "NAK"))
1210                         continue;
1211
1212                 if (skip_prefix(reader->line, "ACK ", &arg)) {
1213                         struct object_id oid;
1214                         if (!get_oid_hex(arg, &oid)) {
1215                                 struct commit *commit;
1216                                 oidset_insert(common, &oid);
1217                                 commit = lookup_commit(the_repository, &oid);
1218                                 negotiator->ack(negotiator, commit);
1219                         }
1220                         continue;
1221                 }
1222
1223                 if (!strcmp(reader->line, "ready")) {
1224                         received_ready = 1;
1225                         continue;
1226                 }
1227
1228                 die(_("unexpected acknowledgment line: '%s'"), reader->line);
1229         }
1230
1231         if (reader->status != PACKET_READ_FLUSH &&
1232             reader->status != PACKET_READ_DELIM)
1233                 die(_("error processing acks: %d"), reader->status);
1234
1235         /*
1236          * If an "acknowledgments" section is sent, a packfile is sent if and
1237          * only if "ready" was sent in this section. The other sections
1238          * ("shallow-info" and "wanted-refs") are sent only if a packfile is
1239          * sent. Therefore, a DELIM is expected if "ready" is sent, and a FLUSH
1240          * otherwise.
1241          */
1242         if (received_ready && reader->status != PACKET_READ_DELIM)
1243                 die(_("expected packfile to be sent after 'ready'"));
1244         if (!received_ready && reader->status != PACKET_READ_FLUSH)
1245                 die(_("expected no other sections to be sent after no 'ready'"));
1246
1247         /* return 0 if no common, 1 if there are common, or 2 if ready */
1248         return received_ready ? 2 : (received_ack ? 1 : 0);
1249 }
1250
1251 static void receive_shallow_info(struct fetch_pack_args *args,
1252                                  struct packet_reader *reader,
1253                                  struct oid_array *shallows,
1254                                  struct shallow_info *si)
1255 {
1256         int unshallow_received = 0;
1257
1258         process_section_header(reader, "shallow-info", 0);
1259         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1260                 const char *arg;
1261                 struct object_id oid;
1262
1263                 if (skip_prefix(reader->line, "shallow ", &arg)) {
1264                         if (get_oid_hex(arg, &oid))
1265                                 die(_("invalid shallow line: %s"), reader->line);
1266                         oid_array_append(shallows, &oid);
1267                         continue;
1268                 }
1269                 if (skip_prefix(reader->line, "unshallow ", &arg)) {
1270                         if (get_oid_hex(arg, &oid))
1271                                 die(_("invalid unshallow line: %s"), reader->line);
1272                         if (!lookup_object(the_repository, oid.hash))
1273                                 die(_("object not found: %s"), reader->line);
1274                         /* make sure that it is parsed as shallow */
1275                         if (!parse_object(the_repository, &oid))
1276                                 die(_("error in object: %s"), reader->line);
1277                         if (unregister_shallow(&oid))
1278                                 die(_("no shallow found: %s"), reader->line);
1279                         unshallow_received = 1;
1280                         continue;
1281                 }
1282                 die(_("expected shallow/unshallow, got %s"), reader->line);
1283         }
1284
1285         if (reader->status != PACKET_READ_FLUSH &&
1286             reader->status != PACKET_READ_DELIM)
1287                 die(_("error processing shallow info: %d"), reader->status);
1288
1289         if (args->deepen || unshallow_received) {
1290                 /*
1291                  * Treat these as shallow lines caused by our depth settings.
1292                  * In v0, these lines cannot cause refs to be rejected; do the
1293                  * same.
1294                  */
1295                 int i;
1296
1297                 for (i = 0; i < shallows->nr; i++)
1298                         register_shallow(the_repository, &shallows->oid[i]);
1299                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
1300                                         NULL);
1301                 args->deepen = 1;
1302         } else if (shallows->nr) {
1303                 /*
1304                  * Treat these as shallow lines caused by the remote being
1305                  * shallow. In v0, remote refs that reach these objects are
1306                  * rejected (unless --update-shallow is set); do the same.
1307                  */
1308                 prepare_shallow_info(si, shallows);
1309                 if (si->nr_ours || si->nr_theirs)
1310                         alternate_shallow_file =
1311                                 setup_temporary_shallow(si->shallow);
1312                 else
1313                         alternate_shallow_file = NULL;
1314         } else {
1315                 alternate_shallow_file = NULL;
1316         }
1317 }
1318
1319 static int cmp_name_ref(const void *name, const void *ref)
1320 {
1321         return strcmp(name, (*(struct ref **)ref)->name);
1322 }
1323
1324 static void receive_wanted_refs(struct packet_reader *reader,
1325                                 struct ref **sought, int nr_sought)
1326 {
1327         process_section_header(reader, "wanted-refs", 0);
1328         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1329                 struct object_id oid;
1330                 const char *end;
1331                 struct ref **found;
1332
1333                 if (parse_oid_hex(reader->line, &oid, &end) || *end++ != ' ')
1334                         die(_("expected wanted-ref, got '%s'"), reader->line);
1335
1336                 found = bsearch(end, sought, nr_sought, sizeof(*sought),
1337                                 cmp_name_ref);
1338                 if (!found)
1339                         die(_("unexpected wanted-ref: '%s'"), reader->line);
1340                 oidcpy(&(*found)->old_oid, &oid);
1341         }
1342
1343         if (reader->status != PACKET_READ_DELIM)
1344                 die(_("error processing wanted refs: %d"), reader->status);
1345 }
1346
1347 enum fetch_state {
1348         FETCH_CHECK_LOCAL = 0,
1349         FETCH_SEND_REQUEST,
1350         FETCH_PROCESS_ACKS,
1351         FETCH_GET_PACK,
1352         FETCH_DONE,
1353 };
1354
1355 static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
1356                                     int fd[2],
1357                                     const struct ref *orig_ref,
1358                                     struct ref **sought, int nr_sought,
1359                                     struct oid_array *shallows,
1360                                     struct shallow_info *si,
1361                                     char **pack_lockfile)
1362 {
1363         struct ref *ref = copy_ref_list(orig_ref);
1364         enum fetch_state state = FETCH_CHECK_LOCAL;
1365         struct oidset common = OIDSET_INIT;
1366         struct packet_reader reader;
1367         int in_vain = 0;
1368         int haves_to_send = INITIAL_FLUSH;
1369         struct fetch_negotiator negotiator;
1370         fetch_negotiator_init(&negotiator, negotiation_algorithm);
1371         packet_reader_init(&reader, fd[0], NULL, 0,
1372                            PACKET_READ_CHOMP_NEWLINE |
1373                            PACKET_READ_DIE_ON_ERR_PACKET);
1374         if (git_env_bool("GIT_TEST_SIDEBAND_ALL", 1) &&
1375             server_supports_feature("fetch", "sideband-all", 0)) {
1376                 reader.use_sideband = 1;
1377                 reader.me = "fetch-pack";
1378         }
1379
1380         while (state != FETCH_DONE) {
1381                 switch (state) {
1382                 case FETCH_CHECK_LOCAL:
1383                         sort_ref_list(&ref, ref_compare_name);
1384                         QSORT(sought, nr_sought, cmp_ref_by_name);
1385
1386                         /* v2 supports these by default */
1387                         allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
1388                         use_sideband = 2;
1389                         if (args->depth > 0 || args->deepen_since || args->deepen_not)
1390                                 args->deepen = 1;
1391
1392                         /* Filter 'ref' by 'sought' and those that aren't local */
1393                         if (!args->no_dependents) {
1394                                 mark_complete_and_common_ref(&negotiator, args, &ref);
1395                                 filter_refs(args, &ref, sought, nr_sought);
1396                                 if (everything_local(args, &ref))
1397                                         state = FETCH_DONE;
1398                                 else
1399                                         state = FETCH_SEND_REQUEST;
1400
1401                                 mark_tips(&negotiator, args->negotiation_tips);
1402                                 for_each_cached_alternate(&negotiator,
1403                                                           insert_one_alternate_object);
1404                         } else {
1405                                 filter_refs(args, &ref, sought, nr_sought);
1406                                 state = FETCH_SEND_REQUEST;
1407                         }
1408                         break;
1409                 case FETCH_SEND_REQUEST:
1410                         if (send_fetch_request(&negotiator, fd[1], args, ref,
1411                                                &common,
1412                                                &haves_to_send, &in_vain,
1413                                                reader.use_sideband))
1414                                 state = FETCH_GET_PACK;
1415                         else
1416                                 state = FETCH_PROCESS_ACKS;
1417                         break;
1418                 case FETCH_PROCESS_ACKS:
1419                         /* Process ACKs/NAKs */
1420                         switch (process_acks(&negotiator, &reader, &common)) {
1421                         case 2:
1422                                 state = FETCH_GET_PACK;
1423                                 break;
1424                         case 1:
1425                                 in_vain = 0;
1426                                 /* fallthrough */
1427                         default:
1428                                 state = FETCH_SEND_REQUEST;
1429                                 break;
1430                         }
1431                         break;
1432                 case FETCH_GET_PACK:
1433                         /* Check for shallow-info section */
1434                         if (process_section_header(&reader, "shallow-info", 1))
1435                                 receive_shallow_info(args, &reader, shallows, si);
1436
1437                         if (process_section_header(&reader, "wanted-refs", 1))
1438                                 receive_wanted_refs(&reader, sought, nr_sought);
1439
1440                         /* get the pack */
1441                         process_section_header(&reader, "packfile", 0);
1442                         if (get_pack(args, fd, pack_lockfile))
1443                                 die(_("git fetch-pack: fetch failed."));
1444
1445                         state = FETCH_DONE;
1446                         break;
1447                 case FETCH_DONE:
1448                         continue;
1449                 }
1450         }
1451
1452         negotiator.release(&negotiator);
1453         oidset_clear(&common);
1454         return ref;
1455 }
1456
1457 static int fetch_pack_config_cb(const char *var, const char *value, void *cb)
1458 {
1459         if (strcmp(var, "fetch.fsck.skiplist") == 0) {
1460                 const char *path;
1461
1462                 if (git_config_pathname(&path, var, value))
1463                         return 1;
1464                 strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
1465                         fsck_msg_types.len ? ',' : '=', path);
1466                 free((char *)path);
1467                 return 0;
1468         }
1469
1470         if (skip_prefix(var, "fetch.fsck.", &var)) {
1471                 if (is_valid_msg_type(var, value))
1472                         strbuf_addf(&fsck_msg_types, "%c%s=%s",
1473                                 fsck_msg_types.len ? ',' : '=', var, value);
1474                 else
1475                         warning("Skipping unknown msg id '%s'", var);
1476                 return 0;
1477         }
1478
1479         return git_default_config(var, value, cb);
1480 }
1481
1482 static void fetch_pack_config(void)
1483 {
1484         git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
1485         git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
1486         git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
1487         git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
1488         git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
1489         git_config_get_string("fetch.negotiationalgorithm",
1490                               &negotiation_algorithm);
1491
1492         git_config(fetch_pack_config_cb, NULL);
1493 }
1494
1495 static void fetch_pack_setup(void)
1496 {
1497         static int did_setup;
1498         if (did_setup)
1499                 return;
1500         fetch_pack_config();
1501         if (0 <= transfer_unpack_limit)
1502                 unpack_limit = transfer_unpack_limit;
1503         else if (0 <= fetch_unpack_limit)
1504                 unpack_limit = fetch_unpack_limit;
1505         did_setup = 1;
1506 }
1507
1508 static int remove_duplicates_in_refs(struct ref **ref, int nr)
1509 {
1510         struct string_list names = STRING_LIST_INIT_NODUP;
1511         int src, dst;
1512
1513         for (src = dst = 0; src < nr; src++) {
1514                 struct string_list_item *item;
1515                 item = string_list_insert(&names, ref[src]->name);
1516                 if (item->util)
1517                         continue; /* already have it */
1518                 item->util = ref[src];
1519                 if (src != dst)
1520                         ref[dst] = ref[src];
1521                 dst++;
1522         }
1523         for (src = dst; src < nr; src++)
1524                 ref[src] = NULL;
1525         string_list_clear(&names, 0);
1526         return dst;
1527 }
1528
1529 static void update_shallow(struct fetch_pack_args *args,
1530                            struct ref **sought, int nr_sought,
1531                            struct shallow_info *si)
1532 {
1533         struct oid_array ref = OID_ARRAY_INIT;
1534         int *status;
1535         int i;
1536
1537         if (args->deepen && alternate_shallow_file) {
1538                 if (*alternate_shallow_file == '\0') { /* --unshallow */
1539                         unlink_or_warn(git_path_shallow(the_repository));
1540                         rollback_lock_file(&shallow_lock);
1541                 } else
1542                         commit_lock_file(&shallow_lock);
1543                 alternate_shallow_file = NULL;
1544                 return;
1545         }
1546
1547         if (!si->shallow || !si->shallow->nr)
1548                 return;
1549
1550         if (args->cloning) {
1551                 /*
1552                  * remote is shallow, but this is a clone, there are
1553                  * no objects in repo to worry about. Accept any
1554                  * shallow points that exist in the pack (iow in repo
1555                  * after get_pack() and reprepare_packed_git())
1556                  */
1557                 struct oid_array extra = OID_ARRAY_INIT;
1558                 struct object_id *oid = si->shallow->oid;
1559                 for (i = 0; i < si->shallow->nr; i++)
1560                         if (has_object_file(&oid[i]))
1561                                 oid_array_append(&extra, &oid[i]);
1562                 if (extra.nr) {
1563                         setup_alternate_shallow(&shallow_lock,
1564                                                 &alternate_shallow_file,
1565                                                 &extra);
1566                         commit_lock_file(&shallow_lock);
1567                         alternate_shallow_file = NULL;
1568                 }
1569                 oid_array_clear(&extra);
1570                 return;
1571         }
1572
1573         if (!si->nr_ours && !si->nr_theirs)
1574                 return;
1575
1576         remove_nonexistent_theirs_shallow(si);
1577         if (!si->nr_ours && !si->nr_theirs)
1578                 return;
1579         for (i = 0; i < nr_sought; i++)
1580                 oid_array_append(&ref, &sought[i]->old_oid);
1581         si->ref = &ref;
1582
1583         if (args->update_shallow) {
1584                 /*
1585                  * remote is also shallow, .git/shallow may be updated
1586                  * so all refs can be accepted. Make sure we only add
1587                  * shallow roots that are actually reachable from new
1588                  * refs.
1589                  */
1590                 struct oid_array extra = OID_ARRAY_INIT;
1591                 struct object_id *oid = si->shallow->oid;
1592                 assign_shallow_commits_to_refs(si, NULL, NULL);
1593                 if (!si->nr_ours && !si->nr_theirs) {
1594                         oid_array_clear(&ref);
1595                         return;
1596                 }
1597                 for (i = 0; i < si->nr_ours; i++)
1598                         oid_array_append(&extra, &oid[si->ours[i]]);
1599                 for (i = 0; i < si->nr_theirs; i++)
1600                         oid_array_append(&extra, &oid[si->theirs[i]]);
1601                 setup_alternate_shallow(&shallow_lock,
1602                                         &alternate_shallow_file,
1603                                         &extra);
1604                 commit_lock_file(&shallow_lock);
1605                 oid_array_clear(&extra);
1606                 oid_array_clear(&ref);
1607                 alternate_shallow_file = NULL;
1608                 return;
1609         }
1610
1611         /*
1612          * remote is also shallow, check what ref is safe to update
1613          * without updating .git/shallow
1614          */
1615         status = xcalloc(nr_sought, sizeof(*status));
1616         assign_shallow_commits_to_refs(si, NULL, status);
1617         if (si->nr_ours || si->nr_theirs) {
1618                 for (i = 0; i < nr_sought; i++)
1619                         if (status[i])
1620                                 sought[i]->status = REF_STATUS_REJECT_SHALLOW;
1621         }
1622         free(status);
1623         oid_array_clear(&ref);
1624 }
1625
1626 static int iterate_ref_map(void *cb_data, struct object_id *oid)
1627 {
1628         struct ref **rm = cb_data;
1629         struct ref *ref = *rm;
1630
1631         if (!ref)
1632                 return -1; /* end of the list */
1633         *rm = ref->next;
1634         oidcpy(oid, &ref->old_oid);
1635         return 0;
1636 }
1637
1638 struct ref *fetch_pack(struct fetch_pack_args *args,
1639                        int fd[],
1640                        const struct ref *ref,
1641                        struct ref **sought, int nr_sought,
1642                        struct oid_array *shallow,
1643                        char **pack_lockfile,
1644                        enum protocol_version version)
1645 {
1646         struct ref *ref_cpy;
1647         struct shallow_info si;
1648         struct oid_array shallows_scratch = OID_ARRAY_INIT;
1649
1650         fetch_pack_setup();
1651         if (nr_sought)
1652                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
1653
1654         if (args->no_dependents && !args->filter_options.choice) {
1655                 /*
1656                  * The protocol does not support requesting that only the
1657                  * wanted objects be sent, so approximate this by setting a
1658                  * "blob:none" filter if no filter is already set. This works
1659                  * for all object types: note that wanted blobs will still be
1660                  * sent because they are directly specified as a "want".
1661                  *
1662                  * NEEDSWORK: Add an option in the protocol to request that
1663                  * only the wanted objects be sent, and implement it.
1664                  */
1665                 parse_list_objects_filter(&args->filter_options, "blob:none");
1666         }
1667
1668         if (version != protocol_v2 && !ref) {
1669                 packet_flush(fd[1]);
1670                 die(_("no matching remote head"));
1671         }
1672         if (version == protocol_v2) {
1673                 if (shallow->nr)
1674                         BUG("Protocol V2 does not provide shallows at this point in the fetch");
1675                 memset(&si, 0, sizeof(si));
1676                 ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
1677                                            &shallows_scratch, &si,
1678                                            pack_lockfile);
1679         } else {
1680                 prepare_shallow_info(&si, shallow);
1681                 ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
1682                                         &si, pack_lockfile);
1683         }
1684         reprepare_packed_git(the_repository);
1685
1686         if (!args->cloning && args->deepen) {
1687                 struct check_connected_options opt = CHECK_CONNECTED_INIT;
1688                 struct ref *iterator = ref_cpy;
1689                 opt.shallow_file = alternate_shallow_file;
1690                 if (args->deepen)
1691                         opt.is_deepening_fetch = 1;
1692                 if (check_connected(iterate_ref_map, &iterator, &opt)) {
1693                         error(_("remote did not send all necessary objects"));
1694                         free_refs(ref_cpy);
1695                         ref_cpy = NULL;
1696                         rollback_lock_file(&shallow_lock);
1697                         goto cleanup;
1698                 }
1699                 args->connectivity_checked = 1;
1700         }
1701
1702         update_shallow(args, sought, nr_sought, &si);
1703 cleanup:
1704         clear_shallow_info(&si);
1705         oid_array_clear(&shallows_scratch);
1706         return ref_cpy;
1707 }
1708
1709 int report_unmatched_refs(struct ref **sought, int nr_sought)
1710 {
1711         int i, ret = 0;
1712
1713         for (i = 0; i < nr_sought; i++) {
1714                 if (!sought[i])
1715                         continue;
1716                 switch (sought[i]->match_status) {
1717                 case REF_MATCHED:
1718                         continue;
1719                 case REF_NOT_MATCHED:
1720                         error(_("no such remote ref %s"), sought[i]->name);
1721                         break;
1722                 case REF_UNADVERTISED_NOT_ALLOWED:
1723                         error(_("Server does not allow request for unadvertised object %s"),
1724                               sought[i]->name);
1725                         break;
1726                 }
1727                 ret = 1;
1728         }
1729         return ret;
1730 }