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