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                 write_or_die(fd, buf->buf, buf->len);
 196 }
 197
 198 static void insert_one_alternate_object(struct fetch_negotiator *negotiator,
 199                                         struct object *obj)
 200 {
 201         rev_list_insert_ref(negotiator, NULL, &obj->oid);
 202 }
 203
 204 #define INITIAL_FLUSH 16
 205 #define PIPESAFE_FLUSH 32
 206 #define LARGE_FLUSH 16384
 207
 208 static int next_flush(int stateless_rpc, int count)
 209 {
 210         if (stateless_rpc) {
 211                 if (count < LARGE_FLUSH)
 212                         count <<= 1;
 213                 else
 214                         count = count * 11 / 10;
 215         } else {
 216                 if (count < PIPESAFE_FLUSH)
 217                         count <<= 1;
 218                 else
 219                         count += PIPESAFE_FLUSH;
 220         }
 221         return count;
 222 }
 223
 224 static void mark_tips(struct fetch_negotiator *negotiator,
 225                       const struct oid_array *negotiation_tips)
 226 {
 227         int i;
 228
 229         if (!negotiation_tips) {
 230                 for_each_ref(rev_list_insert_ref_oid, negotiator);
 231                 return;
 232         }
 233
 234         for (i = 0; i < negotiation_tips->nr; i++)
 235                 rev_list_insert_ref(negotiator, NULL,
 236                                     &negotiation_tips->oid[i]);
 237         return;
 238 }
 239
 240 static int find_common(struct fetch_negotiator *negotiator,
 241                        struct fetch_pack_args *args,
 242                        int fd[2], struct object_id *result_oid,
 243                        struct ref *refs)
 244 {
 245         int fetching;
 246         int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 247         const struct object_id *oid;
 248         unsigned in_vain = 0;
 249         int got_continue = 0;
 250         int got_ready = 0;
 251         struct strbuf req_buf = STRBUF_INIT;
 252         size_t state_len = 0;
 253         struct packet_reader reader;
 254
 255         if (args->stateless_rpc && multi_ack == 1)
 256                 die(_("--stateless-rpc requires multi_ack_detailed"));
 257
 258         packet_reader_init(&reader, fd[0], NULL, 0,
 259                            PACKET_READ_CHOMP_NEWLINE |
 260                            PACKET_READ_DIE_ON_ERR_PACKET);
 261
 262         if (!args->no_dependents) {
 263                 mark_tips(negotiator, args->negotiation_tips);
 264                 for_each_cached_alternate(negotiator, insert_one_alternate_object);
 265         }
 266
 267         fetching = 0;
 268         for ( ; refs ; refs = refs->next) {
 269                 struct object_id *remote = &refs->old_oid;
 270                 const char *remote_hex;
 271                 struct object *o;
 272
 273                 /*
 274                  * If that object is complete (i.e. it is an ancestor of a
 275                  * local ref), we tell them we have it but do not have to
 276                  * tell them about its ancestors, which they already know
 277                  * about.
 278                  *
 279                  * We use lookup_object here because we are only
 280                  * interested in the case we *know* the object is
 281                  * reachable and we have already scanned it.
 282                  *
 283                  * Do this only if args->no_dependents is false (if it is true,
 284                  * we cannot trust the object flags).
 285                  */
 286                 if (!args->no_dependents &&
 287                     ((o = lookup_object(the_repository, remote->hash)) != NULL) &&
 288                                 (o->flags & COMPLETE)) {
 289                         continue;
 290                 }
 291
 292                 remote_hex = oid_to_hex(remote);
 293                 if (!fetching) {
 294                         struct strbuf c = STRBUF_INIT;
 295                         if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 296                         if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 297                         if (no_done)            strbuf_addstr(&c, " no-done");
 298                         if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 299                         if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 300                         if (args->deepen_relative) strbuf_addstr(&c, " deepen-relative");
 301                         if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
 302                         if (args->no_progress)   strbuf_addstr(&c, " no-progress");
 303                         if (args->include_tag)   strbuf_addstr(&c, " include-tag");
 304                         if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 305                         if (deepen_since_ok)    strbuf_addstr(&c, " deepen-since");
 306                         if (deepen_not_ok)      strbuf_addstr(&c, " deepen-not");
 307                         if (agent_supported)    strbuf_addf(&c, " agent=%s",
 308                                                             git_user_agent_sanitized());
 309                         if (args->filter_options.choice)
 310                                 strbuf_addstr(&c, " filter");
 311                         packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 312                         strbuf_release(&c);
 313                 } else
 314                         packet_buf_write(&req_buf, "want %s\n", remote_hex);
 315                 fetching++;
 316         }
 317
 318         if (!fetching) {
 319                 strbuf_release(&req_buf);
 320                 packet_flush(fd[1]);
 321                 return 1;
 322         }
 323
 324         if (is_repository_shallow(the_repository))
 325                 write_shallow_commits(&req_buf, 1, NULL);
 326         if (args->depth > 0)
 327                 packet_buf_write(&req_buf, "deepen %d", args->depth);
 328         if (args->deepen_since) {
 329                 timestamp_t max_age = approxidate(args->deepen_since);
 330                 packet_buf_write(&req_buf, "deepen-since %"PRItime, max_age);
 331         }
 332         if (args->deepen_not) {
 333                 int i;
 334                 for (i = 0; i < args->deepen_not->nr; i++) {
 335                         struct string_list_item *s = args->deepen_not->items + i;
 336                         packet_buf_write(&req_buf, "deepen-not %s", s->string);
 337                 }
 338         }
 339         if (server_supports_filtering && args->filter_options.choice) {
 340                 struct strbuf expanded_filter_spec = STRBUF_INIT;
 341                 expand_list_objects_filter_spec(&args->filter_options,
 342                                                 &expanded_filter_spec);
 343                 packet_buf_write(&req_buf, "filter %s",
 344                                  expanded_filter_spec.buf);
 345                 strbuf_release(&expanded_filter_spec);
 346         }
 347         packet_buf_flush(&req_buf);
 348         state_len = req_buf.len;
 349
 350         if (args->deepen) {
 351                 const char *arg;
 352                 struct object_id oid;
 353
 354                 send_request(args, fd[1], &req_buf);
 355                 while (packet_reader_read(&reader) == PACKET_READ_NORMAL) {
 356                         if (skip_prefix(reader.line, "shallow ", &arg)) {
 357                                 if (get_oid_hex(arg, &oid))
 358                                         die(_("invalid shallow line: %s"), reader.line);
 359                                 register_shallow(the_repository, &oid);
 360                                 continue;
 361                         }
 362                         if (skip_prefix(reader.line, "unshallow ", &arg)) {
 363                                 if (get_oid_hex(arg, &oid))
 364                                         die(_("invalid unshallow line: %s"), reader.line);
 365                                 if (!lookup_object(the_repository, oid.hash))
 366                                         die(_("object not found: %s"), reader.line);
 367                                 /* make sure that it is parsed as shallow */
 368                                 if (!parse_object(the_repository, &oid))
 369                                         die(_("error in object: %s"), reader.line);
 370                                 if (unregister_shallow(&oid))
 371                                         die(_("no shallow found: %s"), reader.line);
 372                                 continue;
 373                         }
 374                         die(_("expected shallow/unshallow, got %s"), reader.line);
 375                 }
 376         } else if (!args->stateless_rpc)
 377                 send_request(args, fd[1], &req_buf);
 378
 379         if (!args->stateless_rpc) {
 380                 /* If we aren't using the stateless-rpc interface
 381                  * we don't need to retain the headers.
 382                  */
 383                 strbuf_setlen(&req_buf, 0);
 384                 state_len = 0;
 385         }
 386
 387         flushes = 0;
 388         retval = -1;
 389         if (args->no_dependents)
 390                 goto done;
 391         while ((oid = negotiator->next(negotiator))) {
 392                 packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid));
 393                 print_verbose(args, "have %s", oid_to_hex(oid));
 394                 in_vain++;
 395                 if (flush_at <= ++count) {
 396                         int ack;
 397
 398                         packet_buf_flush(&req_buf);
 399                         send_request(args, fd[1], &req_buf);
 400                         strbuf_setlen(&req_buf, state_len);
 401                         flushes++;
 402                         flush_at = next_flush(args->stateless_rpc, count);
 403
 404                         /*
 405                          * We keep one window "ahead" of the other side, and
 406                          * will wait for an ACK only on the next one
 407                          */
 408                         if (!args->stateless_rpc && count == INITIAL_FLUSH)
 409                                 continue;
 410
 411                         consume_shallow_list(args, &reader);
 412                         do {
 413                                 ack = get_ack(&reader, result_oid);
 414                                 if (ack)
 415                                         print_verbose(args, _("got %s %d %s"), "ack",
 416                                                       ack, oid_to_hex(result_oid));
 417                                 switch (ack) {
 418                                 case ACK:
 419                                         flushes = 0;
 420                                         multi_ack = 0;
 421                                         retval = 0;
 422                                         goto done;
 423                                 case ACK_common:
 424                                 case ACK_ready:
 425                                 case ACK_continue: {
 426                                         struct commit *commit =
 427                                                 lookup_commit(the_repository,
 428                                                               result_oid);
 429                                         int was_common;
 430
 431                                         if (!commit)
 432                                                 die(_("invalid commit %s"), oid_to_hex(result_oid));
 433                                         was_common = negotiator->ack(negotiator, commit);
 434                                         if (args->stateless_rpc
 435                                          && ack == ACK_common
 436                                          && !was_common) {
 437                                                 /* We need to replay the have for this object
 438                                                  * on the next RPC request so the peer knows
 439                                                  * it is in common with us.
 440                                                  */
 441                                                 const char *hex = oid_to_hex(result_oid);
 442                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 443                                                 state_len = req_buf.len;
 444                                                 /*
 445                                                  * Reset in_vain because an ack
 446                                                  * for this commit has not been
 447                                                  * seen.
 448                                                  */
 449                                                 in_vain = 0;
 450                                         } else if (!args->stateless_rpc
 451                                                    || ack != ACK_common)
 452                                                 in_vain = 0;
 453                                         retval = 0;
 454                                         got_continue = 1;
 455                                         if (ack == ACK_ready)
 456                                                 got_ready = 1;
 457                                         break;
 458                                         }
 459                                 }
 460                         } while (ack);
 461                         flushes--;
 462                         if (got_continue && MAX_IN_VAIN < in_vain) {
 463                                 print_verbose(args, _("giving up"));
 464                                 break; /* give up */
 465                         }
 466                         if (got_ready)
 467                                 break;
 468                 }
 469         }
 470 done:
 471         if (!got_ready || !no_done) {
 472                 packet_buf_write(&req_buf, "done\n");
 473                 send_request(args, fd[1], &req_buf);
 474         }
 475         print_verbose(args, _("done"));
 476         if (retval != 0) {
 477                 multi_ack = 0;
 478                 flushes++;
 479         }
 480         strbuf_release(&req_buf);
 481
 482         if (!got_ready || !no_done)
 483                 consume_shallow_list(args, &reader);
 484         while (flushes || multi_ack) {
 485                 int ack = get_ack(&reader, result_oid);
 486                 if (ack) {
 487                         print_verbose(args, _("got %s (%d) %s"), "ack",
 488                                       ack, oid_to_hex(result_oid));
 489                         if (ack == ACK)
 490                                 return 0;
 491                         multi_ack = 1;
 492                         continue;
 493                 }
 494                 flushes--;
 495         }
 496         /* it is no error to fetch into a completely empty repo */
 497         return count ? retval : 0;
 498 }
 499
 500 static struct commit_list *complete;
 501
 502 static int mark_complete(const struct object_id *oid)
 503 {
 504         struct object *o = parse_object(the_repository, oid);
 505
 506         while (o && o->type == OBJ_TAG) {
 507                 struct tag *t = (struct tag *) o;
 508                 if (!t->tagged)
 509                         break; /* broken repository */
 510                 o->flags |= COMPLETE;
 511                 o = parse_object(the_repository, &t->tagged->oid);
 512         }
 513         if (o && o->type == OBJ_COMMIT) {
 514                 struct commit *commit = (struct commit *)o;
 515                 if (!(commit->object.flags & COMPLETE)) {
 516                         commit->object.flags |= COMPLETE;
 517                         commit_list_insert(commit, &complete);
 518                 }
 519         }
 520         return 0;
 521 }
 522
 523 static int mark_complete_oid(const char *refname, const struct object_id *oid,
 524                              int flag, void *cb_data)
 525 {
 526         return mark_complete(oid);
 527 }
 528
 529 static void mark_recent_complete_commits(struct fetch_pack_args *args,
 530                                          timestamp_t cutoff)
 531 {
 532         while (complete && cutoff <= complete->item->date) {
 533                 print_verbose(args, _("Marking %s as complete"),
 534                               oid_to_hex(&complete->item->object.oid));
 535                 pop_most_recent_commit(&complete, COMPLETE);
 536         }
 537 }
 538
 539 static void add_refs_to_oidset(struct oidset *oids, struct ref *refs)
 540 {
 541         for (; refs; refs = refs->next)
 542                 oidset_insert(oids, &refs->old_oid);
 543 }
 544
 545 static int is_unmatched_ref(const struct ref *ref)
 546 {
 547         struct object_id oid;
 548         const char *p;
 549         return  ref->match_status == REF_NOT_MATCHED &&
 550                 !parse_oid_hex(ref->name, &oid, &p) &&
 551                 *p == '\0' &&
 552                 oideq(&oid, &ref->old_oid);
 553 }
 554
 555 static void filter_refs(struct fetch_pack_args *args,
 556                         struct ref **refs,
 557                         struct ref **sought, int nr_sought)
 558 {
 559         struct ref *newlist = NULL;
 560         struct ref **newtail = &newlist;
 561         struct ref *unmatched = NULL;
 562         struct ref *ref, *next;
 563         struct oidset tip_oids = OIDSET_INIT;
 564         int i;
 565         int strict = !(allow_unadvertised_object_request &
 566                        (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1));
 567
 568         i = 0;
 569         for (ref = *refs; ref; ref = next) {
 570                 int keep = 0;
 571                 next = ref->next;
 572
 573                 if (starts_with(ref->name, "refs/") &&
 574                     check_refname_format(ref->name, 0))
 575                         ; /* trash */
 576                 else {
 577                         while (i < nr_sought) {
 578                                 int cmp = strcmp(ref->name, sought[i]->name);
 579                                 if (cmp < 0)
 580                                         break; /* definitely do not have it */
 581                                 else if (cmp == 0) {
 582                                         keep = 1; /* definitely have it */
 583                                         sought[i]->match_status = REF_MATCHED;
 584                                 }
 585                                 i++;
 586                         }
 587
 588                         if (!keep && args->fetch_all &&
 589                             (!args->deepen || !starts_with(ref->name, "refs/tags/")))
 590                                 keep = 1;
 591                 }
 592
 593                 if (keep) {
 594                         *newtail = ref;
 595                         ref->next = NULL;
 596                         newtail = &ref->next;
 597                 } else {
 598                         ref->next = unmatched;
 599                         unmatched = ref;
 600                 }
 601         }
 602
 603         if (strict) {
 604                 for (i = 0; i < nr_sought; i++) {
 605                         ref = sought[i];
 606                         if (!is_unmatched_ref(ref))
 607                                 continue;
 608
 609                         add_refs_to_oidset(&tip_oids, unmatched);
 610                         add_refs_to_oidset(&tip_oids, newlist);
 611                         break;
 612                 }
 613         }
 614
 615         /* Append unmatched requests to the list */
 616         for (i = 0; i < nr_sought; i++) {
 617                 ref = sought[i];
 618                 if (!is_unmatched_ref(ref))
 619                         continue;
 620
 621                 if (!strict || oidset_contains(&tip_oids, &ref->old_oid)) {
 622                         ref->match_status = REF_MATCHED;
 623                         *newtail = copy_ref(ref);
 624                         newtail = &(*newtail)->next;
 625                 } else {
 626                         ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
 627                 }
 628         }
 629
 630         oidset_clear(&tip_oids);
 631         for (ref = unmatched; ref; ref = next) {
 632                 next = ref->next;
 633                 free(ref);
 634         }
 635
 636         *refs = newlist;
 637 }
 638
 639 static void mark_alternate_complete(struct fetch_negotiator *unused,
 640                                     struct object *obj)
 641 {
 642         mark_complete(&obj->oid);
 643 }
 644
 645 struct loose_object_iter {
 646         struct oidset *loose_object_set;
 647         struct ref *refs;
 648 };
 649
 650 /*
 651  * Mark recent commits available locally and reachable from a local ref as
 652  * COMPLETE. If args->no_dependents is false, also mark COMPLETE remote refs as
 653  * COMMON_REF (otherwise, we are not planning to participate in negotiation, and
 654  * thus do not need COMMON_REF marks).
 655  *
 656  * The cutoff time for recency is determined by this heuristic: it is the
 657  * earliest commit time of the objects in refs that are commits and that we know
 658  * the commit time of.
 659  */
 660 static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
 661                                          struct fetch_pack_args *args,
 662                                          struct ref **refs)
 663 {
 664         struct ref *ref;
 665         int old_save_commit_buffer = save_commit_buffer;
 666         timestamp_t cutoff = 0;
 667
 668         save_commit_buffer = 0;
 669
 670         for (ref = *refs; ref; ref = ref->next) {
 671                 struct object *o;
 672
 673                 if (!has_object_file_with_flags(&ref->old_oid,
 674                                                 OBJECT_INFO_QUICK))
 675                         continue;
 676                 o = parse_object(the_repository, &ref->old_oid);
 677                 if (!o)
 678                         continue;
 679
 680                 /* We already have it -- which may mean that we were
 681                  * in sync with the other side at some time after
 682                  * that (it is OK if we guess wrong here).
 683                  */
 684                 if (o->type == OBJ_COMMIT) {
 685                         struct commit *commit = (struct commit *)o;
 686                         if (!cutoff || cutoff < commit->date)
 687                                 cutoff = commit->date;
 688                 }
 689         }
 690
 691         if (!args->deepen) {
 692                 for_each_ref(mark_complete_oid, NULL);
 693                 for_each_cached_alternate(NULL, mark_alternate_complete);
 694                 commit_list_sort_by_date(&complete);
 695                 if (cutoff)
 696                         mark_recent_complete_commits(args, cutoff);
 697         }
 698
 699         /*
 700          * Mark all complete remote refs as common refs.
 701          * Don't mark them common yet; the server has to be told so first.
 702          */
 703         for (ref = *refs; ref; ref = ref->next) {
 704                 struct object *o = deref_tag(the_repository,
 705                                              lookup_object(the_repository,
 706                                              ref->old_oid.hash),
 707                                              NULL, 0);
 708
 709                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 710                         continue;
 711
 712                 negotiator->known_common(negotiator,
 713                                          (struct commit *)o);
 714         }
 715
 716         save_commit_buffer = old_save_commit_buffer;
 717 }
 718
 719 /*
 720  * Returns 1 if every object pointed to by the given remote refs is available
 721  * locally and reachable from a local ref, and 0 otherwise.
 722  */
 723 static int everything_local(struct fetch_pack_args *args,
 724                             struct ref **refs)
 725 {
 726         struct ref *ref;
 727         int retval;
 728
 729         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 730                 const struct object_id *remote = &ref->old_oid;
 731                 struct object *o;
 732
 733                 o = lookup_object(the_repository, remote->hash);
 734                 if (!o || !(o->flags & COMPLETE)) {
 735                         retval = 0;
 736                         print_verbose(args, "want %s (%s)", oid_to_hex(remote),
 737                                       ref->name);
 738                         continue;
 739                 }
 740                 print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
 741                               ref->name);
 742         }
 743
 744         return retval;
 745 }
 746
 747 static int sideband_demux(int in, int out, void *data)
 748 {
 749         int *xd = data;
 750         int ret;
 751
 752         ret = recv_sideband("fetch-pack", xd[0], out);
 753         close(out);
 754         return ret;
 755 }
 756
 757 static int get_pack(struct fetch_pack_args *args,
 758                     int xd[2], char **pack_lockfile)
 759 {
 760         struct async demux;
 761         int do_keep = args->keep_pack;
 762         const char *cmd_name;
 763         struct pack_header header;
 764         int pass_header = 0;
 765         struct child_process cmd = CHILD_PROCESS_INIT;
 766         int ret;
 767
 768         memset(&demux, 0, sizeof(demux));
 769         if (use_sideband) {
 770                 /* xd[] is talking with upload-pack; subprocess reads from
 771                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 772                  * through demux->out.
 773                  */
 774                 demux.proc = sideband_demux;
 775                 demux.data = xd;
 776                 demux.out = -1;
 777                 demux.isolate_sigpipe = 1;
 778                 if (start_async(&demux))
 779                         die(_("fetch-pack: unable to fork off sideband demultiplexer"));
 780         }
 781         else
 782                 demux.out = xd[0];
 783
 784         if (!args->keep_pack && unpack_limit) {
 785
 786                 if (read_pack_header(demux.out, &header))
 787                         die(_("protocol error: bad pack header"));
 788                 pass_header = 1;
 789                 if (ntohl(header.hdr_entries) < unpack_limit)
 790                         do_keep = 0;
 791                 else
 792                         do_keep = 1;
 793         }
 794
 795         if (alternate_shallow_file) {
 796                 argv_array_push(&cmd.args, "--shallow-file");
 797                 argv_array_push(&cmd.args, alternate_shallow_file);
 798         }
 799
 800         if (do_keep || args->from_promisor) {
 801                 if (pack_lockfile)
 802                         cmd.out = -1;
 803                 cmd_name = "index-pack";
 804                 argv_array_push(&cmd.args, cmd_name);
 805                 argv_array_push(&cmd.args, "--stdin");
 806                 if (!args->quiet && !args->no_progress)
 807                         argv_array_push(&cmd.args, "-v");
 808                 if (args->use_thin_pack)
 809                         argv_array_push(&cmd.args, "--fix-thin");
 810                 if (do_keep && (args->lock_pack || unpack_limit)) {
 811                         char hostname[HOST_NAME_MAX + 1];
 812                         if (xgethostname(hostname, sizeof(hostname)))
 813                                 xsnprintf(hostname, sizeof(hostname), "localhost");
 814                         argv_array_pushf(&cmd.args,
 815                                         "--keep=fetch-pack %"PRIuMAX " on %s",
 816                                         (uintmax_t)getpid(), hostname);
 817                 }
 818                 if (args->check_self_contained_and_connected)
 819                         argv_array_push(&cmd.args, "--check-self-contained-and-connected");
 820                 if (args->from_promisor)
 821                         argv_array_push(&cmd.args, "--promisor");
 822         }
 823         else {
 824                 cmd_name = "unpack-objects";
 825                 argv_array_push(&cmd.args, cmd_name);
 826                 if (args->quiet || args->no_progress)
 827                         argv_array_push(&cmd.args, "-q");
 828                 args->check_self_contained_and_connected = 0;
 829         }
 830
 831         if (pass_header)
 832                 argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
 833                                  ntohl(header.hdr_version),
 834                                  ntohl(header.hdr_entries));
 835         if (fetch_fsck_objects >= 0
 836             ? fetch_fsck_objects
 837             : transfer_fsck_objects >= 0
 838             ? transfer_fsck_objects
 839             : 0) {
 840                 if (args->from_promisor)
 841                         /*
 842                          * We cannot use --strict in index-pack because it
 843                          * checks both broken objects and links, but we only
 844                          * want to check for broken objects.
 845                          */
 846                         argv_array_push(&cmd.args, "--fsck-objects");
 847                 else
 848                         argv_array_pushf(&cmd.args, "--strict%s",
 849                                          fsck_msg_types.buf);
 850         }
 851
 852         cmd.in = demux.out;
 853         cmd.git_cmd = 1;
 854         if (start_command(&cmd))
 855                 die(_("fetch-pack: unable to fork off %s"), cmd_name);
 856         if (do_keep && pack_lockfile) {
 857                 *pack_lockfile = index_pack_lockfile(cmd.out);
 858                 close(cmd.out);
 859         }
 860
 861         if (!use_sideband)
 862                 /* Closed by start_command() */
 863                 xd[0] = -1;
 864
 865         ret = finish_command(&cmd);
 866         if (!ret || (args->check_self_contained_and_connected && ret == 1))
 867                 args->self_contained_and_connected =
 868                         args->check_self_contained_and_connected &&
 869                         ret == 0;
 870         else
 871                 die(_("%s failed"), cmd_name);
 872         if (use_sideband && finish_async(&demux))
 873                 die(_("error in sideband demultiplexer"));
 874         return 0;
 875 }
 876
 877 static int cmp_ref_by_name(const void *a_, const void *b_)
 878 {
 879         const struct ref *a = *((const struct ref **)a_);
 880         const struct ref *b = *((const struct ref **)b_);
 881         return strcmp(a->name, b->name);
 882 }
 883
 884 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 885                                  int fd[2],
 886                                  const struct ref *orig_ref,
 887                                  struct ref **sought, int nr_sought,
 888                                  struct shallow_info *si,
 889                                  char **pack_lockfile)
 890 {
 891         struct ref *ref = copy_ref_list(orig_ref);
 892         struct object_id oid;
 893         const char *agent_feature;
 894         int agent_len;
 895         struct fetch_negotiator negotiator;
 896         fetch_negotiator_init(&negotiator, negotiation_algorithm);
 897
 898         sort_ref_list(&ref, ref_compare_name);
 899         QSORT(sought, nr_sought, cmp_ref_by_name);
 900
 901         if ((args->depth > 0 || is_repository_shallow(the_repository)) && !server_supports("shallow"))
 902                 die(_("Server does not support shallow clients"));
 903         if (args->depth > 0 || args->deepen_since || args->deepen_not)
 904                 args->deepen = 1;
 905         if (server_supports("multi_ack_detailed")) {
 906                 print_verbose(args, _("Server supports multi_ack_detailed"));
 907                 multi_ack = 2;
 908                 if (server_supports("no-done")) {
 909                         print_verbose(args, _("Server supports no-done"));
 910                         if (args->stateless_rpc)
 911                                 no_done = 1;
 912                 }
 913         }
 914         else if (server_supports("multi_ack")) {
 915                 print_verbose(args, _("Server supports multi_ack"));
 916                 multi_ack = 1;
 917         }
 918         if (server_supports("side-band-64k")) {
 919                 print_verbose(args, _("Server supports side-band-64k"));
 920                 use_sideband = 2;
 921         }
 922         else if (server_supports("side-band")) {
 923                 print_verbose(args, _("Server supports side-band"));
 924                 use_sideband = 1;
 925         }
 926         if (server_supports("allow-tip-sha1-in-want")) {
 927                 print_verbose(args, _("Server supports allow-tip-sha1-in-want"));
 928                 allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
 929         }
 930         if (server_supports("allow-reachable-sha1-in-want")) {
 931                 print_verbose(args, _("Server supports allow-reachable-sha1-in-want"));
 932                 allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
 933         }
 934         if (!server_supports("thin-pack"))
 935                 args->use_thin_pack = 0;
 936         if (!server_supports("no-progress"))
 937                 args->no_progress = 0;
 938         if (!server_supports("include-tag"))
 939                 args->include_tag = 0;
 940         if (server_supports("ofs-delta"))
 941                 print_verbose(args, _("Server supports ofs-delta"));
 942         else
 943                 prefer_ofs_delta = 0;
 944
 945         if (server_supports("filter")) {
 946                 server_supports_filtering = 1;
 947                 print_verbose(args, _("Server supports filter"));
 948         } else if (args->filter_options.choice) {
 949                 warning("filtering not recognized by server, ignoring");
 950         }
 951
 952         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 953                 agent_supported = 1;
 954                 if (agent_len)
 955                         print_verbose(args, _("Server version is %.*s"),
 956                                       agent_len, agent_feature);
 957         }
 958         if (server_supports("deepen-since"))
 959                 deepen_since_ok = 1;
 960         else if (args->deepen_since)
 961                 die(_("Server does not support --shallow-since"));
 962         if (server_supports("deepen-not"))
 963                 deepen_not_ok = 1;
 964         else if (args->deepen_not)
 965                 die(_("Server does not support --shallow-exclude"));
 966         if (!server_supports("deepen-relative") && args->deepen_relative)
 967                 die(_("Server does not support --deepen"));
 968
 969         if (!args->no_dependents) {
 970                 mark_complete_and_common_ref(&negotiator, args, &ref);
 971                 filter_refs(args, &ref, sought, nr_sought);
 972                 if (everything_local(args, &ref)) {
 973                         packet_flush(fd[1]);
 974                         goto all_done;
 975                 }
 976         } else {
 977                 filter_refs(args, &ref, sought, nr_sought);
 978         }
 979         if (find_common(&negotiator, args, fd, &oid, ref) < 0)
 980                 if (!args->keep_pack)
 981                         /* When cloning, it is not unusual to have
 982                          * no common commit.
 983                          */
 984                         warning(_("no common commits"));
 985
 986         if (args->stateless_rpc)
 987                 packet_flush(fd[1]);
 988         if (args->deepen)
 989                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
 990                                         NULL);
 991         else if (si->nr_ours || si->nr_theirs)
 992                 alternate_shallow_file = setup_temporary_shallow(si->shallow);
 993         else
 994                 alternate_shallow_file = NULL;
 995         if (get_pack(args, fd, pack_lockfile))
 996                 die(_("git fetch-pack: fetch failed."));
 997
 998  all_done:
 999         negotiator.release(&negotiator);
1000         return ref;
1001 }
1002
1003 static void add_shallow_requests(struct strbuf *req_buf,
1004                                  const struct fetch_pack_args *args)
1005 {
1006         if (is_repository_shallow(the_repository))
1007                 write_shallow_commits(req_buf, 1, NULL);
1008         if (args->depth > 0)
1009                 packet_buf_write(req_buf, "deepen %d", args->depth);
1010         if (args->deepen_since) {
1011                 timestamp_t max_age = approxidate(args->deepen_since);
1012                 packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
1013         }
1014         if (args->deepen_not) {
1015                 int i;
1016                 for (i = 0; i < args->deepen_not->nr; i++) {
1017                         struct string_list_item *s = args->deepen_not->items + i;
1018                         packet_buf_write(req_buf, "deepen-not %s", s->string);
1019                 }
1020         }
1021         if (args->deepen_relative)
1022                 packet_buf_write(req_buf, "deepen-relative\n");
1023 }
1024
1025 static void add_wants(int no_dependents, const struct ref *wants, struct strbuf *req_buf)
1026 {
1027         int use_ref_in_want = server_supports_feature("fetch", "ref-in-want", 0);
1028
1029         for ( ; wants ; wants = wants->next) {
1030                 const struct object_id *remote = &wants->old_oid;
1031                 struct object *o;
1032
1033                 /*
1034                  * If that object is complete (i.e. it is an ancestor of a
1035                  * local ref), we tell them we have it but do not have to
1036                  * tell them about its ancestors, which they already know
1037                  * about.
1038                  *
1039                  * We use lookup_object here because we are only
1040                  * interested in the case we *know* the object is
1041                  * reachable and we have already scanned it.
1042                  *
1043                  * Do this only if args->no_dependents is false (if it is true,
1044                  * we cannot trust the object flags).
1045                  */
1046                 if (!no_dependents &&
1047                     ((o = lookup_object(the_repository, remote->hash)) != NULL) &&
1048                     (o->flags & COMPLETE)) {
1049                         continue;
1050                 }
1051
1052                 if (!use_ref_in_want || wants->exact_oid)
1053                         packet_buf_write(req_buf, "want %s\n", oid_to_hex(remote));
1054                 else
1055                         packet_buf_write(req_buf, "want-ref %s\n", wants->name);
1056         }
1057 }
1058
1059 static void add_common(struct strbuf *req_buf, struct oidset *common)
1060 {
1061         struct oidset_iter iter;
1062         const struct object_id *oid;
1063         oidset_iter_init(common, &iter);
1064
1065         while ((oid = oidset_iter_next(&iter))) {
1066                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1067         }
1068 }
1069
1070 static int add_haves(struct fetch_negotiator *negotiator,
1071                      struct strbuf *req_buf,
1072                      int *haves_to_send, int *in_vain)
1073 {
1074         int ret = 0;
1075         int haves_added = 0;
1076         const struct object_id *oid;
1077
1078         while ((oid = negotiator->next(negotiator))) {
1079                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1080                 if (++haves_added >= *haves_to_send)
1081                         break;
1082         }
1083
1084         *in_vain += haves_added;
1085         if (!haves_added || *in_vain >= MAX_IN_VAIN) {
1086                 /* Send Done */
1087                 packet_buf_write(req_buf, "done\n");
1088                 ret = 1;
1089         }
1090
1091         /* Increase haves to send on next round */
1092         *haves_to_send = next_flush(1, *haves_to_send);
1093
1094         return ret;
1095 }
1096
1097 static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
1098                               const struct fetch_pack_args *args,
1099                               const struct ref *wants, struct oidset *common,
1100                               int *haves_to_send, int *in_vain,
1101                               int sideband_all)
1102 {
1103         int ret = 0;
1104         struct strbuf req_buf = STRBUF_INIT;
1105
1106         if (server_supports_v2("fetch", 1))
1107                 packet_buf_write(&req_buf, "command=fetch");
1108         if (server_supports_v2("agent", 0))
1109                 packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
1110         if (args->server_options && args->server_options->nr &&
1111             server_supports_v2("server-option", 1)) {
1112                 int i;
1113                 for (i = 0; i < args->server_options->nr; i++)
1114                         packet_write_fmt(fd_out, "server-option=%s",
1115                                          args->server_options->items[i].string);
1116         }
1117
1118         packet_buf_delim(&req_buf);
1119         if (args->use_thin_pack)
1120                 packet_buf_write(&req_buf, "thin-pack");
1121         if (args->no_progress)
1122                 packet_buf_write(&req_buf, "no-progress");
1123         if (args->include_tag)
1124                 packet_buf_write(&req_buf, "include-tag");
1125         if (prefer_ofs_delta)
1126                 packet_buf_write(&req_buf, "ofs-delta");
1127         if (sideband_all)
1128                 packet_buf_write(&req_buf, "sideband-all");
1129
1130         /* Add shallow-info and deepen request */
1131         if (server_supports_feature("fetch", "shallow", 0))
1132                 add_shallow_requests(&req_buf, args);
1133         else if (is_repository_shallow(the_repository) || args->deepen)
1134                 die(_("Server does not support shallow requests"));
1135
1136         /* Add filter */
1137         if (server_supports_feature("fetch", "filter", 0) &&
1138             args->filter_options.choice) {
1139                 struct strbuf expanded_filter_spec = STRBUF_INIT;
1140                 print_verbose(args, _("Server supports filter"));
1141                 expand_list_objects_filter_spec(&args->filter_options,
1142                                                 &expanded_filter_spec);
1143                 packet_buf_write(&req_buf, "filter %s",
1144                                  expanded_filter_spec.buf);
1145                 strbuf_release(&expanded_filter_spec);
1146         } else if (args->filter_options.choice) {
1147                 warning("filtering not recognized by server, ignoring");
1148         }
1149
1150         /* add wants */
1151         add_wants(args->no_dependents, wants, &req_buf);
1152
1153         if (args->no_dependents) {
1154                 packet_buf_write(&req_buf, "done");
1155                 ret = 1;
1156         } else {
1157                 /* Add all of the common commits we've found in previous rounds */
1158                 add_common(&req_buf, common);
1159
1160                 /* Add initial haves */
1161                 ret = add_haves(negotiator, &req_buf, haves_to_send, in_vain);
1162         }
1163
1164         /* Send request */
1165         packet_buf_flush(&req_buf);
1166         write_or_die(fd_out, req_buf.buf, req_buf.len);
1167
1168         strbuf_release(&req_buf);
1169         return ret;
1170 }
1171
1172 /*
1173  * Processes a section header in a server's response and checks if it matches
1174  * `section`.  If the value of `peek` is 1, the header line will be peeked (and
1175  * not consumed); if 0, the line will be consumed and the function will die if
1176  * the section header doesn't match what was expected.
1177  */
1178 static int process_section_header(struct packet_reader *reader,
1179                                   const char *section, int peek)
1180 {
1181         int ret;
1182
1183         if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
1184                 die(_("error reading section header '%s'"), section);
1185
1186         ret = !strcmp(reader->line, section);
1187
1188         if (!peek) {
1189                 if (!ret)
1190                         die(_("expected '%s', received '%s'"),
1191                             section, reader->line);
1192                 packet_reader_read(reader);
1193         }
1194
1195         return ret;
1196 }
1197
1198 static int process_acks(struct fetch_negotiator *negotiator,
1199                         struct packet_reader *reader,
1200                         struct oidset *common)
1201 {
1202         /* received */
1203         int received_ready = 0;
1204         int received_ack = 0;
1205
1206         process_section_header(reader, "acknowledgments", 0);
1207         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1208                 const char *arg;
1209
1210                 if (!strcmp(reader->line, "NAK"))
1211                         continue;
1212
1213                 if (skip_prefix(reader->line, "ACK ", &arg)) {
1214                         struct object_id oid;
1215                         if (!get_oid_hex(arg, &oid)) {
1216                                 struct commit *commit;
1217                                 oidset_insert(common, &oid);
1218                                 commit = lookup_commit(the_repository, &oid);
1219                                 negotiator->ack(negotiator, commit);
1220                         }
1221                         continue;
1222                 }
1223
1224                 if (!strcmp(reader->line, "ready")) {
1225                         received_ready = 1;
1226                         continue;
1227                 }
1228
1229                 die(_("unexpected acknowledgment line: '%s'"), reader->line);
1230         }
1231
1232         if (reader->status != PACKET_READ_FLUSH &&
1233             reader->status != PACKET_READ_DELIM)
1234                 die(_("error processing acks: %d"), reader->status);
1235
1236         /*
1237          * If an "acknowledgments" section is sent, a packfile is sent if and
1238          * only if "ready" was sent in this section. The other sections
1239          * ("shallow-info" and "wanted-refs") are sent only if a packfile is
1240          * sent. Therefore, a DELIM is expected if "ready" is sent, and a FLUSH
1241          * otherwise.
1242          */
1243         if (received_ready && reader->status != PACKET_READ_DELIM)
1244                 die(_("expected packfile to be sent after 'ready'"));
1245         if (!received_ready && reader->status != PACKET_READ_FLUSH)
1246                 die(_("expected no other sections to be sent after no 'ready'"));
1247
1248         /* return 0 if no common, 1 if there are common, or 2 if ready */
1249         return received_ready ? 2 : (received_ack ? 1 : 0);
1250 }
1251
1252 static void receive_shallow_info(struct fetch_pack_args *args,
1253                                  struct packet_reader *reader)
1254 {
1255         int line_received = 0;
1256
1257         process_section_header(reader, "shallow-info", 0);
1258         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1259                 const char *arg;
1260                 struct object_id oid;
1261
1262                 if (skip_prefix(reader->line, "shallow ", &arg)) {
1263                         if (get_oid_hex(arg, &oid))
1264                                 die(_("invalid shallow line: %s"), reader->line);
1265                         register_shallow(the_repository, &oid);
1266                         line_received = 1;
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                         line_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 (line_received) {
1290                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
1291                                         NULL);
1292                 args->deepen = 1;
1293         } else {
1294                 alternate_shallow_file = NULL;
1295         }
1296 }
1297
1298 static int cmp_name_ref(const void *name, const void *ref)
1299 {
1300         return strcmp(name, (*(struct ref **)ref)->name);
1301 }
1302
1303 static void receive_wanted_refs(struct packet_reader *reader,
1304                                 struct ref **sought, int nr_sought)
1305 {
1306         process_section_header(reader, "wanted-refs", 0);
1307         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1308                 struct object_id oid;
1309                 const char *end;
1310                 struct ref **found;
1311
1312                 if (parse_oid_hex(reader->line, &oid, &end) || *end++ != ' ')
1313                         die(_("expected wanted-ref, got '%s'"), reader->line);
1314
1315                 found = bsearch(end, sought, nr_sought, sizeof(*sought),
1316                                 cmp_name_ref);
1317                 if (!found)
1318                         die(_("unexpected wanted-ref: '%s'"), reader->line);
1319                 oidcpy(&(*found)->old_oid, &oid);
1320         }
1321
1322         if (reader->status != PACKET_READ_DELIM)
1323                 die(_("error processing wanted refs: %d"), reader->status);
1324 }
1325
1326 enum fetch_state {
1327         FETCH_CHECK_LOCAL = 0,
1328         FETCH_SEND_REQUEST,
1329         FETCH_PROCESS_ACKS,
1330         FETCH_GET_PACK,
1331         FETCH_DONE,
1332 };
1333
1334 static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
1335                                     int fd[2],
1336                                     const struct ref *orig_ref,
1337                                     struct ref **sought, int nr_sought,
1338                                     char **pack_lockfile)
1339 {
1340         struct ref *ref = copy_ref_list(orig_ref);
1341         enum fetch_state state = FETCH_CHECK_LOCAL;
1342         struct oidset common = OIDSET_INIT;
1343         struct packet_reader reader;
1344         int in_vain = 0;
1345         int haves_to_send = INITIAL_FLUSH;
1346         struct fetch_negotiator negotiator;
1347         fetch_negotiator_init(&negotiator, negotiation_algorithm);
1348         packet_reader_init(&reader, fd[0], NULL, 0,
1349                            PACKET_READ_CHOMP_NEWLINE |
1350                            PACKET_READ_DIE_ON_ERR_PACKET);
1351         if (git_env_bool("GIT_TEST_SIDEBAND_ALL", 1) &&
1352             server_supports_feature("fetch", "sideband-all", 0)) {
1353                 reader.use_sideband = 1;
1354                 reader.me = "fetch-pack";
1355         }
1356
1357         while (state != FETCH_DONE) {
1358                 switch (state) {
1359                 case FETCH_CHECK_LOCAL:
1360                         sort_ref_list(&ref, ref_compare_name);
1361                         QSORT(sought, nr_sought, cmp_ref_by_name);
1362
1363                         /* v2 supports these by default */
1364                         allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
1365                         use_sideband = 2;
1366                         if (args->depth > 0 || args->deepen_since || args->deepen_not)
1367                                 args->deepen = 1;
1368
1369                         /* Filter 'ref' by 'sought' and those that aren't local */
1370                         if (!args->no_dependents) {
1371                                 mark_complete_and_common_ref(&negotiator, args, &ref);
1372                                 filter_refs(args, &ref, sought, nr_sought);
1373                                 if (everything_local(args, &ref))
1374                                         state = FETCH_DONE;
1375                                 else
1376                                         state = FETCH_SEND_REQUEST;
1377
1378                                 mark_tips(&negotiator, args->negotiation_tips);
1379                                 for_each_cached_alternate(&negotiator,
1380                                                           insert_one_alternate_object);
1381                         } else {
1382                                 filter_refs(args, &ref, sought, nr_sought);
1383                                 state = FETCH_SEND_REQUEST;
1384                         }
1385                         break;
1386                 case FETCH_SEND_REQUEST:
1387                         if (send_fetch_request(&negotiator, fd[1], args, ref,
1388                                                &common,
1389                                                &haves_to_send, &in_vain,
1390                                                reader.use_sideband))
1391                                 state = FETCH_GET_PACK;
1392                         else
1393                                 state = FETCH_PROCESS_ACKS;
1394                         break;
1395                 case FETCH_PROCESS_ACKS:
1396                         /* Process ACKs/NAKs */
1397                         switch (process_acks(&negotiator, &reader, &common)) {
1398                         case 2:
1399                                 state = FETCH_GET_PACK;
1400                                 break;
1401                         case 1:
1402                                 in_vain = 0;
1403                                 /* fallthrough */
1404                         default:
1405                                 state = FETCH_SEND_REQUEST;
1406                                 break;
1407                         }
1408                         break;
1409                 case FETCH_GET_PACK:
1410                         /* Check for shallow-info section */
1411                         if (process_section_header(&reader, "shallow-info", 1))
1412                                 receive_shallow_info(args, &reader);
1413
1414                         if (process_section_header(&reader, "wanted-refs", 1))
1415                                 receive_wanted_refs(&reader, sought, nr_sought);
1416
1417                         /* get the pack */
1418                         process_section_header(&reader, "packfile", 0);
1419                         if (get_pack(args, fd, pack_lockfile))
1420                                 die(_("git fetch-pack: fetch failed."));
1421
1422                         state = FETCH_DONE;
1423                         break;
1424                 case FETCH_DONE:
1425                         continue;
1426                 }
1427         }
1428
1429         negotiator.release(&negotiator);
1430         oidset_clear(&common);
1431         return ref;
1432 }
1433
1434 static int fetch_pack_config_cb(const char *var, const char *value, void *cb)
1435 {
1436         if (strcmp(var, "fetch.fsck.skiplist") == 0) {
1437                 const char *path;
1438
1439                 if (git_config_pathname(&path, var, value))
1440                         return 1;
1441                 strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
1442                         fsck_msg_types.len ? ',' : '=', path);
1443                 free((char *)path);
1444                 return 0;
1445         }
1446
1447         if (skip_prefix(var, "fetch.fsck.", &var)) {
1448                 if (is_valid_msg_type(var, value))
1449                         strbuf_addf(&fsck_msg_types, "%c%s=%s",
1450                                 fsck_msg_types.len ? ',' : '=', var, value);
1451                 else
1452                         warning("Skipping unknown msg id '%s'", var);
1453                 return 0;
1454         }
1455
1456         return git_default_config(var, value, cb);
1457 }
1458
1459 static void fetch_pack_config(void)
1460 {
1461         git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
1462         git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
1463         git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
1464         git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
1465         git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
1466         git_config_get_string("fetch.negotiationalgorithm",
1467                               &negotiation_algorithm);
1468
1469         git_config(fetch_pack_config_cb, NULL);
1470 }
1471
1472 static void fetch_pack_setup(void)
1473 {
1474         static int did_setup;
1475         if (did_setup)
1476                 return;
1477         fetch_pack_config();
1478         if (0 <= transfer_unpack_limit)
1479                 unpack_limit = transfer_unpack_limit;
1480         else if (0 <= fetch_unpack_limit)
1481                 unpack_limit = fetch_unpack_limit;
1482         did_setup = 1;
1483 }
1484
1485 static int remove_duplicates_in_refs(struct ref **ref, int nr)
1486 {
1487         struct string_list names = STRING_LIST_INIT_NODUP;
1488         int src, dst;
1489
1490         for (src = dst = 0; src < nr; src++) {
1491                 struct string_list_item *item;
1492                 item = string_list_insert(&names, ref[src]->name);
1493                 if (item->util)
1494                         continue; /* already have it */
1495                 item->util = ref[src];
1496                 if (src != dst)
1497                         ref[dst] = ref[src];
1498                 dst++;
1499         }
1500         for (src = dst; src < nr; src++)
1501                 ref[src] = NULL;
1502         string_list_clear(&names, 0);
1503         return dst;
1504 }
1505
1506 static void update_shallow(struct fetch_pack_args *args,
1507                            struct ref **sought, int nr_sought,
1508                            struct shallow_info *si)
1509 {
1510         struct oid_array ref = OID_ARRAY_INIT;
1511         int *status;
1512         int i;
1513
1514         if (args->deepen && alternate_shallow_file) {
1515                 if (*alternate_shallow_file == '\0') { /* --unshallow */
1516                         unlink_or_warn(git_path_shallow(the_repository));
1517                         rollback_lock_file(&shallow_lock);
1518                 } else
1519                         commit_lock_file(&shallow_lock);
1520                 alternate_shallow_file = NULL;
1521                 return;
1522         }
1523
1524         if (!si->shallow || !si->shallow->nr)
1525                 return;
1526
1527         if (args->cloning) {
1528                 /*
1529                  * remote is shallow, but this is a clone, there are
1530                  * no objects in repo to worry about. Accept any
1531                  * shallow points that exist in the pack (iow in repo
1532                  * after get_pack() and reprepare_packed_git())
1533                  */
1534                 struct oid_array extra = OID_ARRAY_INIT;
1535                 struct object_id *oid = si->shallow->oid;
1536                 for (i = 0; i < si->shallow->nr; i++)
1537                         if (has_object_file(&oid[i]))
1538                                 oid_array_append(&extra, &oid[i]);
1539                 if (extra.nr) {
1540                         setup_alternate_shallow(&shallow_lock,
1541                                                 &alternate_shallow_file,
1542                                                 &extra);
1543                         commit_lock_file(&shallow_lock);
1544                         alternate_shallow_file = NULL;
1545                 }
1546                 oid_array_clear(&extra);
1547                 return;
1548         }
1549
1550         if (!si->nr_ours && !si->nr_theirs)
1551                 return;
1552
1553         remove_nonexistent_theirs_shallow(si);
1554         if (!si->nr_ours && !si->nr_theirs)
1555                 return;
1556         for (i = 0; i < nr_sought; i++)
1557                 oid_array_append(&ref, &sought[i]->old_oid);
1558         si->ref = &ref;
1559
1560         if (args->update_shallow) {
1561                 /*
1562                  * remote is also shallow, .git/shallow may be updated
1563                  * so all refs can be accepted. Make sure we only add
1564                  * shallow roots that are actually reachable from new
1565                  * refs.
1566                  */
1567                 struct oid_array extra = OID_ARRAY_INIT;
1568                 struct object_id *oid = si->shallow->oid;
1569                 assign_shallow_commits_to_refs(si, NULL, NULL);
1570                 if (!si->nr_ours && !si->nr_theirs) {
1571                         oid_array_clear(&ref);
1572                         return;
1573                 }
1574                 for (i = 0; i < si->nr_ours; i++)
1575                         oid_array_append(&extra, &oid[si->ours[i]]);
1576                 for (i = 0; i < si->nr_theirs; i++)
1577                         oid_array_append(&extra, &oid[si->theirs[i]]);
1578                 setup_alternate_shallow(&shallow_lock,
1579                                         &alternate_shallow_file,
1580                                         &extra);
1581                 commit_lock_file(&shallow_lock);
1582                 oid_array_clear(&extra);
1583                 oid_array_clear(&ref);
1584                 alternate_shallow_file = NULL;
1585                 return;
1586         }
1587
1588         /*
1589          * remote is also shallow, check what ref is safe to update
1590          * without updating .git/shallow
1591          */
1592         status = xcalloc(nr_sought, sizeof(*status));
1593         assign_shallow_commits_to_refs(si, NULL, status);
1594         if (si->nr_ours || si->nr_theirs) {
1595                 for (i = 0; i < nr_sought; i++)
1596                         if (status[i])
1597                                 sought[i]->status = REF_STATUS_REJECT_SHALLOW;
1598         }
1599         free(status);
1600         oid_array_clear(&ref);
1601 }
1602
1603 static int iterate_ref_map(void *cb_data, struct object_id *oid)
1604 {
1605         struct ref **rm = cb_data;
1606         struct ref *ref = *rm;
1607
1608         if (!ref)
1609                 return -1; /* end of the list */
1610         *rm = ref->next;
1611         oidcpy(oid, &ref->old_oid);
1612         return 0;
1613 }
1614
1615 struct ref *fetch_pack(struct fetch_pack_args *args,
1616                        int fd[], struct child_process *conn,
1617                        const struct ref *ref,
1618                        const char *dest,
1619                        struct ref **sought, int nr_sought,
1620                        struct oid_array *shallow,
1621                        char **pack_lockfile,
1622                        enum protocol_version version)
1623 {
1624         struct ref *ref_cpy;
1625         struct shallow_info si;
1626
1627         fetch_pack_setup();
1628         if (nr_sought)
1629                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
1630
1631         if (args->no_dependents && !args->filter_options.choice) {
1632                 /*
1633                  * The protocol does not support requesting that only the
1634                  * wanted objects be sent, so approximate this by setting a
1635                  * "blob:none" filter if no filter is already set. This works
1636                  * for all object types: note that wanted blobs will still be
1637                  * sent because they are directly specified as a "want".
1638                  *
1639                  * NEEDSWORK: Add an option in the protocol to request that
1640                  * only the wanted objects be sent, and implement it.
1641                  */
1642                 parse_list_objects_filter(&args->filter_options, "blob:none");
1643         }
1644
1645         if (version != protocol_v2 && !ref) {
1646                 packet_flush(fd[1]);
1647                 die(_("no matching remote head"));
1648         }
1649         prepare_shallow_info(&si, shallow);
1650         if (version == protocol_v2)
1651                 ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
1652                                            pack_lockfile);
1653         else
1654                 ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
1655                                         &si, pack_lockfile);
1656         reprepare_packed_git(the_repository);
1657
1658         if (!args->cloning && args->deepen) {
1659                 struct check_connected_options opt = CHECK_CONNECTED_INIT;
1660                 struct ref *iterator = ref_cpy;
1661                 opt.shallow_file = alternate_shallow_file;
1662                 if (args->deepen)
1663                         opt.is_deepening_fetch = 1;
1664                 if (check_connected(iterate_ref_map, &iterator, &opt)) {
1665                         error(_("remote did not send all necessary objects"));
1666                         free_refs(ref_cpy);
1667                         ref_cpy = NULL;
1668                         rollback_lock_file(&shallow_lock);
1669                         goto cleanup;
1670                 }
1671                 args->connectivity_checked = 1;
1672         }
1673
1674         update_shallow(args, sought, nr_sought, &si);
1675 cleanup:
1676         clear_shallow_info(&si);
1677         return ref_cpy;
1678 }
1679
1680 int report_unmatched_refs(struct ref **sought, int nr_sought)
1681 {
1682         int i, ret = 0;
1683
1684         for (i = 0; i < nr_sought; i++) {
1685                 if (!sought[i])
1686                         continue;
1687                 switch (sought[i]->match_status) {
1688                 case REF_MATCHED:
1689                         continue;
1690                 case REF_NOT_MATCHED:
1691                         error(_("no such remote ref %s"), sought[i]->name);
1692                         break;
1693                 case REF_UNADVERTISED_NOT_ALLOWED:
1694                         error(_("Server does not allow request for unadvertised object %s"),
1695                               sought[i]->name);
1696                         break;
1697                 }
1698                 ret = 1;
1699         }
1700         return ret;
1701 }