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 struct strbuf fsck_msg_types = STRBUF_INIT;
  40
  41 /* Remember to update object flag allocation in object.h */
  42 #define COMPLETE        (1U << 0)
  43 #define ALTERNATE       (1U << 1)
  44
  45 /*
  46  * After sending this many "have"s if we do not get any new ACK , we
  47  * give up traversing our history.
  48  */
  49 #define MAX_IN_VAIN 256
  50
  51 static int multi_ack, use_sideband;
  52 /* Allow specifying sha1 if it is a ref tip. */
  53 #define ALLOW_TIP_SHA1  01
  54 /* Allow request of a sha1 if it is reachable from a ref (possibly hidden ref). */
  55 #define ALLOW_REACHABLE_SHA1    02
  56 static unsigned int allow_unadvertised_object_request;
  57
  58 __attribute__((format (printf, 2, 3)))
  59 static inline void print_verbose(const struct fetch_pack_args *args,
  60                                  const char *fmt, ...)
  61 {
  62         va_list params;
  63
  64         if (!args->verbose)
  65                 return;
  66
  67         va_start(params, fmt);
  68         vfprintf(stderr, fmt, params);
  69         va_end(params);
  70         fputc('\n', stderr);
  71 }
  72
  73 struct alternate_object_cache {
  74         struct object **items;
  75         size_t nr, alloc;
  76 };
  77
  78 static void cache_one_alternate(const struct object_id *oid,
  79                                 void *vcache)
  80 {
  81         struct alternate_object_cache *cache = vcache;
  82         struct object *obj = parse_object(the_repository, oid);
  83
  84         if (!obj || (obj->flags & ALTERNATE))
  85                 return;
  86
  87         obj->flags |= ALTERNATE;
  88         ALLOC_GROW(cache->items, cache->nr + 1, cache->alloc);
  89         cache->items[cache->nr++] = obj;
  90 }
  91
  92 static void for_each_cached_alternate(struct fetch_negotiator *negotiator,
  93                                       void (*cb)(struct fetch_negotiator *,
  94                                                  struct object *))
  95 {
  96         static int initialized;
  97         static struct alternate_object_cache cache;
  98         size_t i;
  99
 100         if (!initialized) {
 101                 for_each_alternate_ref(cache_one_alternate, &cache);
 102                 initialized = 1;
 103         }
 104
 105         for (i = 0; i < cache.nr; i++)
 106                 cb(negotiator, cache.items[i]);
 107 }
 108
 109 static int rev_list_insert_ref(struct fetch_negotiator *negotiator,
 110                                const char *refname,
 111                                const struct object_id *oid)
 112 {
 113         struct object *o = deref_tag(the_repository,
 114                                      parse_object(the_repository, oid),
 115                                      refname, 0);
 116
 117         if (o && o->type == OBJ_COMMIT)
 118                 negotiator->add_tip(negotiator, (struct commit *)o);
 119
 120         return 0;
 121 }
 122
 123 static int rev_list_insert_ref_oid(const char *refname, const struct object_id *oid,
 124                                    int flag, void *cb_data)
 125 {
 126         return rev_list_insert_ref(cb_data, refname, oid);
 127 }
 128
 129 enum ack_type {
 130         NAK = 0,
 131         ACK,
 132         ACK_continue,
 133         ACK_common,
 134         ACK_ready
 135 };
 136
 137 static void consume_shallow_list(struct fetch_pack_args *args,
 138                                  struct packet_reader *reader)
 139 {
 140         if (args->stateless_rpc && args->deepen) {
 141                 /* If we sent a depth we will get back "duplicate"
 142                  * shallow and unshallow commands every time there
 143                  * is a block of have lines exchanged.
 144                  */
 145                 while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 146                         if (starts_with(reader->line, "shallow "))
 147                                 continue;
 148                         if (starts_with(reader->line, "unshallow "))
 149                                 continue;
 150                         die(_("git fetch-pack: expected shallow list"));
 151                 }
 152                 if (reader->status != PACKET_READ_FLUSH)
 153                         die(_("git fetch-pack: expected a flush packet after shallow list"));
 154         }
 155 }
 156
 157 static enum ack_type get_ack(struct packet_reader *reader,
 158                              struct object_id *result_oid)
 159 {
 160         int len;
 161         const char *arg;
 162
 163         if (packet_reader_read(reader) != PACKET_READ_NORMAL)
 164                 die(_("git fetch-pack: expected ACK/NAK, got a flush packet"));
 165         len = reader->pktlen;
 166
 167         if (!strcmp(reader->line, "NAK"))
 168                 return NAK;
 169         if (skip_prefix(reader->line, "ACK ", &arg)) {
 170                 const char *p;
 171                 if (!parse_oid_hex(arg, result_oid, &p)) {
 172                         len -= p - reader->line;
 173                         if (len < 1)
 174                                 return ACK;
 175                         if (strstr(p, "continue"))
 176                                 return ACK_continue;
 177                         if (strstr(p, "common"))
 178                                 return ACK_common;
 179                         if (strstr(p, "ready"))
 180                                 return ACK_ready;
 181                         return ACK;
 182                 }
 183         }
 184         die(_("git fetch-pack: expected ACK/NAK, got '%s'"), reader->line);
 185 }
 186
 187 static void send_request(struct fetch_pack_args *args,
 188                          int fd, struct strbuf *buf)
 189 {
 190         if (args->stateless_rpc) {
 191                 send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 192                 packet_flush(fd);
 193         } else {
 194                 if (write_in_full(fd, buf->buf, buf->len) < 0)
 195                         die_errno(_("unable to write to remote"));
 196         }
 197 }
 198
 199 static void insert_one_alternate_object(struct fetch_negotiator *negotiator,
 200                                         struct object *obj)
 201 {
 202         rev_list_insert_ref(negotiator, NULL, &obj->oid);
 203 }
 204
 205 #define INITIAL_FLUSH 16
 206 #define PIPESAFE_FLUSH 32
 207 #define LARGE_FLUSH 16384
 208
 209 static int next_flush(int stateless_rpc, int count)
 210 {
 211         if (stateless_rpc) {
 212                 if (count < LARGE_FLUSH)
 213                         count <<= 1;
 214                 else
 215                         count = count * 11 / 10;
 216         } else {
 217                 if (count < PIPESAFE_FLUSH)
 218                         count <<= 1;
 219                 else
 220                         count += PIPESAFE_FLUSH;
 221         }
 222         return count;
 223 }
 224
 225 static void mark_tips(struct fetch_negotiator *negotiator,
 226                       const struct oid_array *negotiation_tips)
 227 {
 228         int i;
 229
 230         if (!negotiation_tips) {
 231                 for_each_ref(rev_list_insert_ref_oid, negotiator);
 232                 return;
 233         }
 234
 235         for (i = 0; i < negotiation_tips->nr; i++)
 236                 rev_list_insert_ref(negotiator, NULL,
 237                                     &negotiation_tips->oid[i]);
 238         return;
 239 }
 240
 241 static int find_common(struct fetch_negotiator *negotiator,
 242                        struct fetch_pack_args *args,
 243                        int fd[2], struct object_id *result_oid,
 244                        struct ref *refs)
 245 {
 246         int fetching;
 247         int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 248         const struct object_id *oid;
 249         unsigned in_vain = 0;
 250         int got_continue = 0;
 251         int got_ready = 0;
 252         struct strbuf req_buf = STRBUF_INIT;
 253         size_t state_len = 0;
 254         struct packet_reader reader;
 255
 256         if (args->stateless_rpc && multi_ack == 1)
 257                 die(_("--stateless-rpc requires multi_ack_detailed"));
 258
 259         packet_reader_init(&reader, fd[0], NULL, 0,
 260                            PACKET_READ_CHOMP_NEWLINE |
 261                            PACKET_READ_DIE_ON_ERR_PACKET);
 262
 263         if (!args->no_dependents) {
 264                 mark_tips(negotiator, args->negotiation_tips);
 265                 for_each_cached_alternate(negotiator, insert_one_alternate_object);
 266         }
 267
 268         fetching = 0;
 269         for ( ; refs ; refs = refs->next) {
 270                 struct object_id *remote = &refs->old_oid;
 271                 const char *remote_hex;
 272                 struct object *o;
 273
 274                 /*
 275                  * If that object is complete (i.e. it is an ancestor of a
 276                  * local ref), we tell them we have it but do not have to
 277                  * tell them about its ancestors, which they already know
 278                  * about.
 279                  *
 280                  * We use lookup_object here because we are only
 281                  * interested in the case we *know* the object is
 282                  * reachable and we have already scanned it.
 283                  *
 284                  * Do this only if args->no_dependents is false (if it is true,
 285                  * we cannot trust the object flags).
 286                  */
 287                 if (!args->no_dependents &&
 288                     ((o = lookup_object(the_repository, remote)) != NULL) &&
 289                                 (o->flags & COMPLETE)) {
 290                         continue;
 291                 }
 292
 293                 remote_hex = oid_to_hex(remote);
 294                 if (!fetching) {
 295                         struct strbuf c = STRBUF_INIT;
 296                         if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 297                         if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 298                         if (no_done)            strbuf_addstr(&c, " no-done");
 299                         if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 300                         if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 301                         if (args->deepen_relative) strbuf_addstr(&c, " deepen-relative");
 302                         if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
 303                         if (args->no_progress)   strbuf_addstr(&c, " no-progress");
 304                         if (args->include_tag)   strbuf_addstr(&c, " include-tag");
 305                         if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 306                         if (deepen_since_ok)    strbuf_addstr(&c, " deepen-since");
 307                         if (deepen_not_ok)      strbuf_addstr(&c, " deepen-not");
 308                         if (agent_supported)    strbuf_addf(&c, " agent=%s",
 309                                                             git_user_agent_sanitized());
 310                         if (args->filter_options.choice)
 311                                 strbuf_addstr(&c, " filter");
 312                         packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 313                         strbuf_release(&c);
 314                 } else
 315                         packet_buf_write(&req_buf, "want %s\n", remote_hex);
 316                 fetching++;
 317         }
 318
 319         if (!fetching) {
 320                 strbuf_release(&req_buf);
 321                 packet_flush(fd[1]);
 322                 return 1;
 323         }
 324
 325         if (is_repository_shallow(the_repository))
 326                 write_shallow_commits(&req_buf, 1, NULL);
 327         if (args->depth > 0)
 328                 packet_buf_write(&req_buf, "deepen %d", args->depth);
 329         if (args->deepen_since) {
 330                 timestamp_t max_age = approxidate(args->deepen_since);
 331                 packet_buf_write(&req_buf, "deepen-since %"PRItime, max_age);
 332         }
 333         if (args->deepen_not) {
 334                 int i;
 335                 for (i = 0; i < args->deepen_not->nr; i++) {
 336                         struct string_list_item *s = args->deepen_not->items + i;
 337                         packet_buf_write(&req_buf, "deepen-not %s", s->string);
 338                 }
 339         }
 340         if (server_supports_filtering && args->filter_options.choice) {
 341                 const char *spec =
 342                         expand_list_objects_filter_spec(&args->filter_options);
 343                 packet_buf_write(&req_buf, "filter %s", spec);
 344         }
 345         packet_buf_flush(&req_buf);
 346         state_len = req_buf.len;
 347
 348         if (args->deepen) {
 349                 const char *arg;
 350                 struct object_id oid;
 351
 352                 send_request(args, fd[1], &req_buf);
 353                 while (packet_reader_read(&reader) == PACKET_READ_NORMAL) {
 354                         if (skip_prefix(reader.line, "shallow ", &arg)) {
 355                                 if (get_oid_hex(arg, &oid))
 356                                         die(_("invalid shallow line: %s"), reader.line);
 357                                 register_shallow(the_repository, &oid);
 358                                 continue;
 359                         }
 360                         if (skip_prefix(reader.line, "unshallow ", &arg)) {
 361                                 if (get_oid_hex(arg, &oid))
 362                                         die(_("invalid unshallow line: %s"), reader.line);
 363                                 if (!lookup_object(the_repository, &oid))
 364                                         die(_("object not found: %s"), reader.line);
 365                                 /* make sure that it is parsed as shallow */
 366                                 if (!parse_object(the_repository, &oid))
 367                                         die(_("error in object: %s"), reader.line);
 368                                 if (unregister_shallow(&oid))
 369                                         die(_("no shallow found: %s"), reader.line);
 370                                 continue;
 371                         }
 372                         die(_("expected shallow/unshallow, got %s"), reader.line);
 373                 }
 374         } else if (!args->stateless_rpc)
 375                 send_request(args, fd[1], &req_buf);
 376
 377         if (!args->stateless_rpc) {
 378                 /* If we aren't using the stateless-rpc interface
 379                  * we don't need to retain the headers.
 380                  */
 381                 strbuf_setlen(&req_buf, 0);
 382                 state_len = 0;
 383         }
 384
 385         trace2_region_enter("fetch-pack", "negotiation_v0_v1", the_repository);
 386         flushes = 0;
 387         retval = -1;
 388         if (args->no_dependents)
 389                 goto done;
 390         while ((oid = negotiator->next(negotiator))) {
 391                 packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid));
 392                 print_verbose(args, "have %s", oid_to_hex(oid));
 393                 in_vain++;
 394                 if (flush_at <= ++count) {
 395                         int ack;
 396
 397                         packet_buf_flush(&req_buf);
 398                         send_request(args, fd[1], &req_buf);
 399                         strbuf_setlen(&req_buf, state_len);
 400                         flushes++;
 401                         flush_at = next_flush(args->stateless_rpc, count);
 402
 403                         /*
 404                          * We keep one window "ahead" of the other side, and
 405                          * will wait for an ACK only on the next one
 406                          */
 407                         if (!args->stateless_rpc && count == INITIAL_FLUSH)
 408                                 continue;
 409
 410                         consume_shallow_list(args, &reader);
 411                         do {
 412                                 ack = get_ack(&reader, result_oid);
 413                                 if (ack)
 414                                         print_verbose(args, _("got %s %d %s"), "ack",
 415                                                       ack, oid_to_hex(result_oid));
 416                                 switch (ack) {
 417                                 case ACK:
 418                                         flushes = 0;
 419                                         multi_ack = 0;
 420                                         retval = 0;
 421                                         goto done;
 422                                 case ACK_common:
 423                                 case ACK_ready:
 424                                 case ACK_continue: {
 425                                         struct commit *commit =
 426                                                 lookup_commit(the_repository,
 427                                                               result_oid);
 428                                         int was_common;
 429
 430                                         if (!commit)
 431                                                 die(_("invalid commit %s"), oid_to_hex(result_oid));
 432                                         was_common = negotiator->ack(negotiator, commit);
 433                                         if (args->stateless_rpc
 434                                          && ack == ACK_common
 435                                          && !was_common) {
 436                                                 /* We need to replay the have for this object
 437                                                  * on the next RPC request so the peer knows
 438                                                  * it is in common with us.
 439                                                  */
 440                                                 const char *hex = oid_to_hex(result_oid);
 441                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 442                                                 state_len = req_buf.len;
 443                                                 /*
 444                                                  * Reset in_vain because an ack
 445                                                  * for this commit has not been
 446                                                  * seen.
 447                                                  */
 448                                                 in_vain = 0;
 449                                         } else if (!args->stateless_rpc
 450                                                    || ack != ACK_common)
 451                                                 in_vain = 0;
 452                                         retval = 0;
 453                                         got_continue = 1;
 454                                         if (ack == ACK_ready)
 455                                                 got_ready = 1;
 456                                         break;
 457                                         }
 458                                 }
 459                         } while (ack);
 460                         flushes--;
 461                         if (got_continue && MAX_IN_VAIN < in_vain) {
 462                                 print_verbose(args, _("giving up"));
 463                                 break; /* give up */
 464                         }
 465                         if (got_ready)
 466                                 break;
 467                 }
 468         }
 469 done:
 470         trace2_region_leave("fetch-pack", "negotiation_v0_v1", the_repository);
 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                         /*
 576                          * trash or a peeled value; do not even add it to
 577                          * unmatched list
 578                          */
 579                         free_one_ref(ref);
 580                         continue;
 581                 } else {
 582                         while (i < nr_sought) {
 583                                 int cmp = strcmp(ref->name, sought[i]->name);
 584                                 if (cmp < 0)
 585                                         break; /* definitely do not have it */
 586                                 else if (cmp == 0) {
 587                                         keep = 1; /* definitely have it */
 588                                         sought[i]->match_status = REF_MATCHED;
 589                                 }
 590                                 i++;
 591                         }
 592
 593                         if (!keep && args->fetch_all &&
 594                             (!args->deepen || !starts_with(ref->name, "refs/tags/")))
 595                                 keep = 1;
 596                 }
 597
 598                 if (keep) {
 599                         *newtail = ref;
 600                         ref->next = NULL;
 601                         newtail = &ref->next;
 602                 } else {
 603                         ref->next = unmatched;
 604                         unmatched = ref;
 605                 }
 606         }
 607
 608         if (strict) {
 609                 for (i = 0; i < nr_sought; i++) {
 610                         ref = sought[i];
 611                         if (!is_unmatched_ref(ref))
 612                                 continue;
 613
 614                         add_refs_to_oidset(&tip_oids, unmatched);
 615                         add_refs_to_oidset(&tip_oids, newlist);
 616                         break;
 617                 }
 618         }
 619
 620         /* Append unmatched requests to the list */
 621         for (i = 0; i < nr_sought; i++) {
 622                 ref = sought[i];
 623                 if (!is_unmatched_ref(ref))
 624                         continue;
 625
 626                 if (!strict || oidset_contains(&tip_oids, &ref->old_oid)) {
 627                         ref->match_status = REF_MATCHED;
 628                         *newtail = copy_ref(ref);
 629                         newtail = &(*newtail)->next;
 630                 } else {
 631                         ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
 632                 }
 633         }
 634
 635         oidset_clear(&tip_oids);
 636         free_refs(unmatched);
 637
 638         *refs = newlist;
 639 }
 640
 641 static void mark_alternate_complete(struct fetch_negotiator *unused,
 642                                     struct object *obj)
 643 {
 644         mark_complete(&obj->oid);
 645 }
 646
 647 struct loose_object_iter {
 648         struct oidset *loose_object_set;
 649         struct ref *refs;
 650 };
 651
 652 /*
 653  * Mark recent commits available locally and reachable from a local ref as
 654  * COMPLETE. If args->no_dependents is false, also mark COMPLETE remote refs as
 655  * COMMON_REF (otherwise, we are not planning to participate in negotiation, and
 656  * thus do not need COMMON_REF marks).
 657  *
 658  * The cutoff time for recency is determined by this heuristic: it is the
 659  * earliest commit time of the objects in refs that are commits and that we know
 660  * the commit time of.
 661  */
 662 static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
 663                                          struct fetch_pack_args *args,
 664                                          struct ref **refs)
 665 {
 666         struct ref *ref;
 667         int old_save_commit_buffer = save_commit_buffer;
 668         timestamp_t cutoff = 0;
 669
 670         save_commit_buffer = 0;
 671
 672         for (ref = *refs; ref; ref = ref->next) {
 673                 struct object *o;
 674
 675                 if (!has_object_file_with_flags(&ref->old_oid,
 676                                                 OBJECT_INFO_QUICK |
 677                                                         OBJECT_INFO_SKIP_FETCH_OBJECT))
 678                         continue;
 679                 o = parse_object(the_repository, &ref->old_oid);
 680                 if (!o)
 681                         continue;
 682
 683                 /* We already have it -- which may mean that we were
 684                  * in sync with the other side at some time after
 685                  * that (it is OK if we guess wrong here).
 686                  */
 687                 if (o->type == OBJ_COMMIT) {
 688                         struct commit *commit = (struct commit *)o;
 689                         if (!cutoff || cutoff < commit->date)
 690                                 cutoff = commit->date;
 691                 }
 692         }
 693
 694         if (!args->deepen) {
 695                 for_each_ref(mark_complete_oid, NULL);
 696                 for_each_cached_alternate(NULL, mark_alternate_complete);
 697                 commit_list_sort_by_date(&complete);
 698                 if (cutoff)
 699                         mark_recent_complete_commits(args, cutoff);
 700         }
 701
 702         /*
 703          * Mark all complete remote refs as common refs.
 704          * Don't mark them common yet; the server has to be told so first.
 705          */
 706         for (ref = *refs; ref; ref = ref->next) {
 707                 struct object *o = deref_tag(the_repository,
 708                                              lookup_object(the_repository,
 709                                              &ref->old_oid),
 710                                              NULL, 0);
 711
 712                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 713                         continue;
 714
 715                 negotiator->known_common(negotiator,
 716                                          (struct commit *)o);
 717         }
 718
 719         save_commit_buffer = old_save_commit_buffer;
 720 }
 721
 722 /*
 723  * Returns 1 if every object pointed to by the given remote refs is available
 724  * locally and reachable from a local ref, and 0 otherwise.
 725  */
 726 static int everything_local(struct fetch_pack_args *args,
 727                             struct ref **refs)
 728 {
 729         struct ref *ref;
 730         int retval;
 731
 732         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 733                 const struct object_id *remote = &ref->old_oid;
 734                 struct object *o;
 735
 736                 o = lookup_object(the_repository, remote);
 737                 if (!o || !(o->flags & COMPLETE)) {
 738                         retval = 0;
 739                         print_verbose(args, "want %s (%s)", oid_to_hex(remote),
 740                                       ref->name);
 741                         continue;
 742                 }
 743                 print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
 744                               ref->name);
 745         }
 746
 747         return retval;
 748 }
 749
 750 static int sideband_demux(int in, int out, void *data)
 751 {
 752         int *xd = data;
 753         int ret;
 754
 755         ret = recv_sideband("fetch-pack", xd[0], out);
 756         close(out);
 757         return ret;
 758 }
 759
 760 static void write_promisor_file(const char *keep_name,
 761                                 struct ref **sought, int nr_sought)
 762 {
 763         struct strbuf promisor_name = STRBUF_INIT;
 764         int suffix_stripped;
 765         FILE *output;
 766         int i;
 767
 768         strbuf_addstr(&promisor_name, keep_name);
 769         suffix_stripped = strbuf_strip_suffix(&promisor_name, ".keep");
 770         if (!suffix_stripped)
 771                 BUG("name of pack lockfile should end with .keep (was '%s')",
 772                     keep_name);
 773         strbuf_addstr(&promisor_name, ".promisor");
 774
 775         output = xfopen(promisor_name.buf, "w");
 776         for (i = 0; i < nr_sought; i++)
 777                 fprintf(output, "%s %s\n", oid_to_hex(&sought[i]->old_oid),
 778                         sought[i]->name);
 779         fclose(output);
 780
 781         strbuf_release(&promisor_name);
 782 }
 783
 784 static int get_pack(struct fetch_pack_args *args,
 785                     int xd[2], char **pack_lockfile,
 786                     struct ref **sought, int nr_sought)
 787 {
 788         struct async demux;
 789         int do_keep = args->keep_pack;
 790         const char *cmd_name;
 791         struct pack_header header;
 792         int pass_header = 0;
 793         struct child_process cmd = CHILD_PROCESS_INIT;
 794         int ret;
 795
 796         memset(&demux, 0, sizeof(demux));
 797         if (use_sideband) {
 798                 /* xd[] is talking with upload-pack; subprocess reads from
 799                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 800                  * through demux->out.
 801                  */
 802                 demux.proc = sideband_demux;
 803                 demux.data = xd;
 804                 demux.out = -1;
 805                 demux.isolate_sigpipe = 1;
 806                 if (start_async(&demux))
 807                         die(_("fetch-pack: unable to fork off sideband demultiplexer"));
 808         }
 809         else
 810                 demux.out = xd[0];
 811
 812         if (!args->keep_pack && unpack_limit) {
 813
 814                 if (read_pack_header(demux.out, &header))
 815                         die(_("protocol error: bad pack header"));
 816                 pass_header = 1;
 817                 if (ntohl(header.hdr_entries) < unpack_limit)
 818                         do_keep = 0;
 819                 else
 820                         do_keep = 1;
 821         }
 822
 823         if (alternate_shallow_file) {
 824                 argv_array_push(&cmd.args, "--shallow-file");
 825                 argv_array_push(&cmd.args, alternate_shallow_file);
 826         }
 827
 828         if (do_keep || args->from_promisor) {
 829                 if (pack_lockfile)
 830                         cmd.out = -1;
 831                 cmd_name = "index-pack";
 832                 argv_array_push(&cmd.args, cmd_name);
 833                 argv_array_push(&cmd.args, "--stdin");
 834                 if (!args->quiet && !args->no_progress)
 835                         argv_array_push(&cmd.args, "-v");
 836                 if (args->use_thin_pack)
 837                         argv_array_push(&cmd.args, "--fix-thin");
 838                 if (do_keep && (args->lock_pack || unpack_limit)) {
 839                         char hostname[HOST_NAME_MAX + 1];
 840                         if (xgethostname(hostname, sizeof(hostname)))
 841                                 xsnprintf(hostname, sizeof(hostname), "localhost");
 842                         argv_array_pushf(&cmd.args,
 843                                         "--keep=fetch-pack %"PRIuMAX " on %s",
 844                                         (uintmax_t)getpid(), hostname);
 845                 }
 846                 if (args->check_self_contained_and_connected)
 847                         argv_array_push(&cmd.args, "--check-self-contained-and-connected");
 848                 /*
 849                  * If we're obtaining the filename of a lockfile, we'll use
 850                  * that filename to write a .promisor file with more
 851                  * information below. If not, we need index-pack to do it for
 852                  * us.
 853                  */
 854                 if (!(do_keep && pack_lockfile) && args->from_promisor)
 855                         argv_array_push(&cmd.args, "--promisor");
 856         }
 857         else {
 858                 cmd_name = "unpack-objects";
 859                 argv_array_push(&cmd.args, cmd_name);
 860                 if (args->quiet || args->no_progress)
 861                         argv_array_push(&cmd.args, "-q");
 862                 args->check_self_contained_and_connected = 0;
 863         }
 864
 865         if (pass_header)
 866                 argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
 867                                  ntohl(header.hdr_version),
 868                                  ntohl(header.hdr_entries));
 869         if (fetch_fsck_objects >= 0
 870             ? fetch_fsck_objects
 871             : transfer_fsck_objects >= 0
 872             ? transfer_fsck_objects
 873             : 0) {
 874                 if (args->from_promisor)
 875                         /*
 876                          * We cannot use --strict in index-pack because it
 877                          * checks both broken objects and links, but we only
 878                          * want to check for broken objects.
 879                          */
 880                         argv_array_push(&cmd.args, "--fsck-objects");
 881                 else
 882                         argv_array_pushf(&cmd.args, "--strict%s",
 883                                          fsck_msg_types.buf);
 884         }
 885
 886         cmd.in = demux.out;
 887         cmd.git_cmd = 1;
 888         if (start_command(&cmd))
 889                 die(_("fetch-pack: unable to fork off %s"), cmd_name);
 890         if (do_keep && pack_lockfile) {
 891                 *pack_lockfile = index_pack_lockfile(cmd.out);
 892                 close(cmd.out);
 893         }
 894
 895         if (!use_sideband)
 896                 /* Closed by start_command() */
 897                 xd[0] = -1;
 898
 899         ret = finish_command(&cmd);
 900         if (!ret || (args->check_self_contained_and_connected && ret == 1))
 901                 args->self_contained_and_connected =
 902                         args->check_self_contained_and_connected &&
 903                         ret == 0;
 904         else
 905                 die(_("%s failed"), cmd_name);
 906         if (use_sideband && finish_async(&demux))
 907                 die(_("error in sideband demultiplexer"));
 908
 909         /*
 910          * Now that index-pack has succeeded, write the promisor file using the
 911          * obtained .keep filename if necessary
 912          */
 913         if (do_keep && pack_lockfile && args->from_promisor)
 914                 write_promisor_file(*pack_lockfile, sought, nr_sought);
 915
 916         return 0;
 917 }
 918
 919 static int cmp_ref_by_name(const void *a_, const void *b_)
 920 {
 921         const struct ref *a = *((const struct ref **)a_);
 922         const struct ref *b = *((const struct ref **)b_);
 923         return strcmp(a->name, b->name);
 924 }
 925
 926 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 927                                  int fd[2],
 928                                  const struct ref *orig_ref,
 929                                  struct ref **sought, int nr_sought,
 930                                  struct shallow_info *si,
 931                                  char **pack_lockfile)
 932 {
 933         struct repository *r = the_repository;
 934         struct ref *ref = copy_ref_list(orig_ref);
 935         struct object_id oid;
 936         const char *agent_feature;
 937         int agent_len;
 938         struct fetch_negotiator negotiator_alloc;
 939         struct fetch_negotiator *negotiator;
 940
 941         if (args->no_dependents) {
 942                 negotiator = NULL;
 943         } else {
 944                 negotiator = &negotiator_alloc;
 945                 fetch_negotiator_init(r, negotiator);
 946         }
 947
 948         sort_ref_list(&ref, ref_compare_name);
 949         QSORT(sought, nr_sought, cmp_ref_by_name);
 950
 951         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 952                 agent_supported = 1;
 953                 if (agent_len)
 954                         print_verbose(args, _("Server version is %.*s"),
 955                                       agent_len, agent_feature);
 956         }
 957
 958         if (server_supports("shallow"))
 959                 print_verbose(args, _("Server supports %s"), "shallow");
 960         else if (args->depth > 0 || is_repository_shallow(r))
 961                 die(_("Server does not support shallow clients"));
 962         if (args->depth > 0 || args->deepen_since || args->deepen_not)
 963                 args->deepen = 1;
 964         if (server_supports("multi_ack_detailed")) {
 965                 print_verbose(args, _("Server supports %s"), "multi_ack_detailed");
 966                 multi_ack = 2;
 967                 if (server_supports("no-done")) {
 968                         print_verbose(args, _("Server supports %s"), "no-done");
 969                         if (args->stateless_rpc)
 970                                 no_done = 1;
 971                 }
 972         }
 973         else if (server_supports("multi_ack")) {
 974                 print_verbose(args, _("Server supports %s"), "multi_ack");
 975                 multi_ack = 1;
 976         }
 977         if (server_supports("side-band-64k")) {
 978                 print_verbose(args, _("Server supports %s"), "side-band-64k");
 979                 use_sideband = 2;
 980         }
 981         else if (server_supports("side-band")) {
 982                 print_verbose(args, _("Server supports %s"), "side-band");
 983                 use_sideband = 1;
 984         }
 985         if (server_supports("allow-tip-sha1-in-want")) {
 986                 print_verbose(args, _("Server supports %s"), "allow-tip-sha1-in-want");
 987                 allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
 988         }
 989         if (server_supports("allow-reachable-sha1-in-want")) {
 990                 print_verbose(args, _("Server supports %s"), "allow-reachable-sha1-in-want");
 991                 allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
 992         }
 993         if (server_supports("thin-pack"))
 994                 print_verbose(args, _("Server supports %s"), "thin-pack");
 995         else
 996                 args->use_thin_pack = 0;
 997         if (server_supports("no-progress"))
 998                 print_verbose(args, _("Server supports %s"), "no-progress");
 999         else
1000                 args->no_progress = 0;
1001         if (server_supports("include-tag"))
1002                 print_verbose(args, _("Server supports %s"), "include-tag");
1003         else
1004                 args->include_tag = 0;
1005         if (server_supports("ofs-delta"))
1006                 print_verbose(args, _("Server supports %s"), "ofs-delta");
1007         else
1008                 prefer_ofs_delta = 0;
1009
1010         if (server_supports("filter")) {
1011                 server_supports_filtering = 1;
1012                 print_verbose(args, _("Server supports %s"), "filter");
1013         } else if (args->filter_options.choice) {
1014                 warning("filtering not recognized by server, ignoring");
1015         }
1016
1017         if (server_supports("deepen-since")) {
1018                 print_verbose(args, _("Server supports %s"), "deepen-since");
1019                 deepen_since_ok = 1;
1020         } else if (args->deepen_since)
1021                 die(_("Server does not support --shallow-since"));
1022         if (server_supports("deepen-not")) {
1023                 print_verbose(args, _("Server supports %s"), "deepen-not");
1024                 deepen_not_ok = 1;
1025         } else if (args->deepen_not)
1026                 die(_("Server does not support --shallow-exclude"));
1027         if (server_supports("deepen-relative"))
1028                 print_verbose(args, _("Server supports %s"), "deepen-relative");
1029         else if (args->deepen_relative)
1030                 die(_("Server does not support --deepen"));
1031
1032         if (!args->no_dependents) {
1033                 mark_complete_and_common_ref(negotiator, args, &ref);
1034                 filter_refs(args, &ref, sought, nr_sought);
1035                 if (everything_local(args, &ref)) {
1036                         packet_flush(fd[1]);
1037                         goto all_done;
1038                 }
1039         } else {
1040                 filter_refs(args, &ref, sought, nr_sought);
1041         }
1042         if (find_common(negotiator, args, fd, &oid, ref) < 0)
1043                 if (!args->keep_pack)
1044                         /* When cloning, it is not unusual to have
1045                          * no common commit.
1046                          */
1047                         warning(_("no common commits"));
1048
1049         if (args->stateless_rpc)
1050                 packet_flush(fd[1]);
1051         if (args->deepen)
1052                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
1053                                         NULL);
1054         else if (si->nr_ours || si->nr_theirs)
1055                 alternate_shallow_file = setup_temporary_shallow(si->shallow);
1056         else
1057                 alternate_shallow_file = NULL;
1058         if (get_pack(args, fd, pack_lockfile, sought, nr_sought))
1059                 die(_("git fetch-pack: fetch failed."));
1060
1061  all_done:
1062         if (negotiator)
1063                 negotiator->release(negotiator);
1064         return ref;
1065 }
1066
1067 static void add_shallow_requests(struct strbuf *req_buf,
1068                                  const struct fetch_pack_args *args)
1069 {
1070         if (is_repository_shallow(the_repository))
1071                 write_shallow_commits(req_buf, 1, NULL);
1072         if (args->depth > 0)
1073                 packet_buf_write(req_buf, "deepen %d", args->depth);
1074         if (args->deepen_since) {
1075                 timestamp_t max_age = approxidate(args->deepen_since);
1076                 packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
1077         }
1078         if (args->deepen_not) {
1079                 int i;
1080                 for (i = 0; i < args->deepen_not->nr; i++) {
1081                         struct string_list_item *s = args->deepen_not->items + i;
1082                         packet_buf_write(req_buf, "deepen-not %s", s->string);
1083                 }
1084         }
1085         if (args->deepen_relative)
1086                 packet_buf_write(req_buf, "deepen-relative\n");
1087 }
1088
1089 static void add_wants(int no_dependents, const struct ref *wants, struct strbuf *req_buf)
1090 {
1091         int use_ref_in_want = server_supports_feature("fetch", "ref-in-want", 0);
1092
1093         for ( ; wants ; wants = wants->next) {
1094                 const struct object_id *remote = &wants->old_oid;
1095                 struct object *o;
1096
1097                 /*
1098                  * If that object is complete (i.e. it is an ancestor of a
1099                  * local ref), we tell them we have it but do not have to
1100                  * tell them about its ancestors, which they already know
1101                  * about.
1102                  *
1103                  * We use lookup_object here because we are only
1104                  * interested in the case we *know* the object is
1105                  * reachable and we have already scanned it.
1106                  *
1107                  * Do this only if args->no_dependents is false (if it is true,
1108                  * we cannot trust the object flags).
1109                  */
1110                 if (!no_dependents &&
1111                     ((o = lookup_object(the_repository, remote)) != NULL) &&
1112                     (o->flags & COMPLETE)) {
1113                         continue;
1114                 }
1115
1116                 if (!use_ref_in_want || wants->exact_oid)
1117                         packet_buf_write(req_buf, "want %s\n", oid_to_hex(remote));
1118                 else
1119                         packet_buf_write(req_buf, "want-ref %s\n", wants->name);
1120         }
1121 }
1122
1123 static void add_common(struct strbuf *req_buf, struct oidset *common)
1124 {
1125         struct oidset_iter iter;
1126         const struct object_id *oid;
1127         oidset_iter_init(common, &iter);
1128
1129         while ((oid = oidset_iter_next(&iter))) {
1130                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1131         }
1132 }
1133
1134 static int add_haves(struct fetch_negotiator *negotiator,
1135                      struct strbuf *req_buf,
1136                      int *haves_to_send, int *in_vain)
1137 {
1138         int ret = 0;
1139         int haves_added = 0;
1140         const struct object_id *oid;
1141
1142         while ((oid = negotiator->next(negotiator))) {
1143                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1144                 if (++haves_added >= *haves_to_send)
1145                         break;
1146         }
1147
1148         *in_vain += haves_added;
1149         if (!haves_added || *in_vain >= MAX_IN_VAIN) {
1150                 /* Send Done */
1151                 packet_buf_write(req_buf, "done\n");
1152                 ret = 1;
1153         }
1154
1155         /* Increase haves to send on next round */
1156         *haves_to_send = next_flush(1, *haves_to_send);
1157
1158         return ret;
1159 }
1160
1161 static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
1162                               struct fetch_pack_args *args,
1163                               const struct ref *wants, struct oidset *common,
1164                               int *haves_to_send, int *in_vain,
1165                               int sideband_all)
1166 {
1167         int ret = 0;
1168         struct strbuf req_buf = STRBUF_INIT;
1169
1170         if (server_supports_v2("fetch", 1))
1171                 packet_buf_write(&req_buf, "command=fetch");
1172         if (server_supports_v2("agent", 0))
1173                 packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
1174         if (args->server_options && args->server_options->nr &&
1175             server_supports_v2("server-option", 1)) {
1176                 int i;
1177                 for (i = 0; i < args->server_options->nr; i++)
1178                         packet_buf_write(&req_buf, "server-option=%s",
1179                                          args->server_options->items[i].string);
1180         }
1181
1182         packet_buf_delim(&req_buf);
1183         if (args->use_thin_pack)
1184                 packet_buf_write(&req_buf, "thin-pack");
1185         if (args->no_progress)
1186                 packet_buf_write(&req_buf, "no-progress");
1187         if (args->include_tag)
1188                 packet_buf_write(&req_buf, "include-tag");
1189         if (prefer_ofs_delta)
1190                 packet_buf_write(&req_buf, "ofs-delta");
1191         if (sideband_all)
1192                 packet_buf_write(&req_buf, "sideband-all");
1193
1194         /* Add shallow-info and deepen request */
1195         if (server_supports_feature("fetch", "shallow", 0))
1196                 add_shallow_requests(&req_buf, args);
1197         else if (is_repository_shallow(the_repository) || args->deepen)
1198                 die(_("Server does not support shallow requests"));
1199
1200         /* Add filter */
1201         if (server_supports_feature("fetch", "filter", 0) &&
1202             args->filter_options.choice) {
1203                 const char *spec =
1204                         expand_list_objects_filter_spec(&args->filter_options);
1205                 print_verbose(args, _("Server supports filter"));
1206                 packet_buf_write(&req_buf, "filter %s", spec);
1207         } else if (args->filter_options.choice) {
1208                 warning("filtering not recognized by server, ignoring");
1209         }
1210
1211         /* add wants */
1212         add_wants(args->no_dependents, wants, &req_buf);
1213
1214         if (args->no_dependents) {
1215                 packet_buf_write(&req_buf, "done");
1216                 ret = 1;
1217         } else {
1218                 /* Add all of the common commits we've found in previous rounds */
1219                 add_common(&req_buf, common);
1220
1221                 /* Add initial haves */
1222                 ret = add_haves(negotiator, &req_buf, haves_to_send, in_vain);
1223         }
1224
1225         /* Send request */
1226         packet_buf_flush(&req_buf);
1227         if (write_in_full(fd_out, req_buf.buf, req_buf.len) < 0)
1228                 die_errno(_("unable to write request to remote"));
1229
1230         strbuf_release(&req_buf);
1231         return ret;
1232 }
1233
1234 /*
1235  * Processes a section header in a server's response and checks if it matches
1236  * `section`.  If the value of `peek` is 1, the header line will be peeked (and
1237  * not consumed); if 0, the line will be consumed and the function will die if
1238  * the section header doesn't match what was expected.
1239  */
1240 static int process_section_header(struct packet_reader *reader,
1241                                   const char *section, int peek)
1242 {
1243         int ret;
1244
1245         if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
1246                 die(_("error reading section header '%s'"), section);
1247
1248         ret = !strcmp(reader->line, section);
1249
1250         if (!peek) {
1251                 if (!ret)
1252                         die(_("expected '%s', received '%s'"),
1253                             section, reader->line);
1254                 packet_reader_read(reader);
1255         }
1256
1257         return ret;
1258 }
1259
1260 static int process_acks(struct fetch_negotiator *negotiator,
1261                         struct packet_reader *reader,
1262                         struct oidset *common)
1263 {
1264         /* received */
1265         int received_ready = 0;
1266         int received_ack = 0;
1267
1268         process_section_header(reader, "acknowledgments", 0);
1269         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1270                 const char *arg;
1271
1272                 if (!strcmp(reader->line, "NAK"))
1273                         continue;
1274
1275                 if (skip_prefix(reader->line, "ACK ", &arg)) {
1276                         struct object_id oid;
1277                         if (!get_oid_hex(arg, &oid)) {
1278                                 struct commit *commit;
1279                                 oidset_insert(common, &oid);
1280                                 commit = lookup_commit(the_repository, &oid);
1281                                 if (negotiator)
1282                                         negotiator->ack(negotiator, commit);
1283                         }
1284                         continue;
1285                 }
1286
1287                 if (!strcmp(reader->line, "ready")) {
1288                         received_ready = 1;
1289                         continue;
1290                 }
1291
1292                 die(_("unexpected acknowledgment line: '%s'"), reader->line);
1293         }
1294
1295         if (reader->status != PACKET_READ_FLUSH &&
1296             reader->status != PACKET_READ_DELIM)
1297                 die(_("error processing acks: %d"), reader->status);
1298
1299         /*
1300          * If an "acknowledgments" section is sent, a packfile is sent if and
1301          * only if "ready" was sent in this section. The other sections
1302          * ("shallow-info" and "wanted-refs") are sent only if a packfile is
1303          * sent. Therefore, a DELIM is expected if "ready" is sent, and a FLUSH
1304          * otherwise.
1305          */
1306         if (received_ready && reader->status != PACKET_READ_DELIM)
1307                 die(_("expected packfile to be sent after 'ready'"));
1308         if (!received_ready && reader->status != PACKET_READ_FLUSH)
1309                 die(_("expected no other sections to be sent after no 'ready'"));
1310
1311         /* return 0 if no common, 1 if there are common, or 2 if ready */
1312         return received_ready ? 2 : (received_ack ? 1 : 0);
1313 }
1314
1315 static void receive_shallow_info(struct fetch_pack_args *args,
1316                                  struct packet_reader *reader,
1317                                  struct oid_array *shallows,
1318                                  struct shallow_info *si)
1319 {
1320         int unshallow_received = 0;
1321
1322         process_section_header(reader, "shallow-info", 0);
1323         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1324                 const char *arg;
1325                 struct object_id oid;
1326
1327                 if (skip_prefix(reader->line, "shallow ", &arg)) {
1328                         if (get_oid_hex(arg, &oid))
1329                                 die(_("invalid shallow line: %s"), reader->line);
1330                         oid_array_append(shallows, &oid);
1331                         continue;
1332                 }
1333                 if (skip_prefix(reader->line, "unshallow ", &arg)) {
1334                         if (get_oid_hex(arg, &oid))
1335                                 die(_("invalid unshallow line: %s"), reader->line);
1336                         if (!lookup_object(the_repository, &oid))
1337                                 die(_("object not found: %s"), reader->line);
1338                         /* make sure that it is parsed as shallow */
1339                         if (!parse_object(the_repository, &oid))
1340                                 die(_("error in object: %s"), reader->line);
1341                         if (unregister_shallow(&oid))
1342                                 die(_("no shallow found: %s"), reader->line);
1343                         unshallow_received = 1;
1344                         continue;
1345                 }
1346                 die(_("expected shallow/unshallow, got %s"), reader->line);
1347         }
1348
1349         if (reader->status != PACKET_READ_FLUSH &&
1350             reader->status != PACKET_READ_DELIM)
1351                 die(_("error processing shallow info: %d"), reader->status);
1352
1353         if (args->deepen || unshallow_received) {
1354                 /*
1355                  * Treat these as shallow lines caused by our depth settings.
1356                  * In v0, these lines cannot cause refs to be rejected; do the
1357                  * same.
1358                  */
1359                 int i;
1360
1361                 for (i = 0; i < shallows->nr; i++)
1362                         register_shallow(the_repository, &shallows->oid[i]);
1363                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
1364                                         NULL);
1365                 args->deepen = 1;
1366         } else if (shallows->nr) {
1367                 /*
1368                  * Treat these as shallow lines caused by the remote being
1369                  * shallow. In v0, remote refs that reach these objects are
1370                  * rejected (unless --update-shallow is set); do the same.
1371                  */
1372                 prepare_shallow_info(si, shallows);
1373                 if (si->nr_ours || si->nr_theirs)
1374                         alternate_shallow_file =
1375                                 setup_temporary_shallow(si->shallow);
1376                 else
1377                         alternate_shallow_file = NULL;
1378         } else {
1379                 alternate_shallow_file = NULL;
1380         }
1381 }
1382
1383 static int cmp_name_ref(const void *name, const void *ref)
1384 {
1385         return strcmp(name, (*(struct ref **)ref)->name);
1386 }
1387
1388 static void receive_wanted_refs(struct packet_reader *reader,
1389                                 struct ref **sought, int nr_sought)
1390 {
1391         process_section_header(reader, "wanted-refs", 0);
1392         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1393                 struct object_id oid;
1394                 const char *end;
1395                 struct ref **found;
1396
1397                 if (parse_oid_hex(reader->line, &oid, &end) || *end++ != ' ')
1398                         die(_("expected wanted-ref, got '%s'"), reader->line);
1399
1400                 found = bsearch(end, sought, nr_sought, sizeof(*sought),
1401                                 cmp_name_ref);
1402                 if (!found)
1403                         die(_("unexpected wanted-ref: '%s'"), reader->line);
1404                 oidcpy(&(*found)->old_oid, &oid);
1405         }
1406
1407         if (reader->status != PACKET_READ_DELIM)
1408                 die(_("error processing wanted refs: %d"), reader->status);
1409 }
1410
1411 enum fetch_state {
1412         FETCH_CHECK_LOCAL = 0,
1413         FETCH_SEND_REQUEST,
1414         FETCH_PROCESS_ACKS,
1415         FETCH_GET_PACK,
1416         FETCH_DONE,
1417 };
1418
1419 static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
1420                                     int fd[2],
1421                                     const struct ref *orig_ref,
1422                                     struct ref **sought, int nr_sought,
1423                                     struct oid_array *shallows,
1424                                     struct shallow_info *si,
1425                                     char **pack_lockfile)
1426 {
1427         struct repository *r = the_repository;
1428         struct ref *ref = copy_ref_list(orig_ref);
1429         enum fetch_state state = FETCH_CHECK_LOCAL;
1430         struct oidset common = OIDSET_INIT;
1431         struct packet_reader reader;
1432         int in_vain = 0, negotiation_started = 0;
1433         int haves_to_send = INITIAL_FLUSH;
1434         struct fetch_negotiator negotiator_alloc;
1435         struct fetch_negotiator *negotiator;
1436
1437         if (args->no_dependents) {
1438                 negotiator = NULL;
1439         } else {
1440                 negotiator = &negotiator_alloc;
1441                 fetch_negotiator_init(r, negotiator);
1442         }
1443
1444         packet_reader_init(&reader, fd[0], NULL, 0,
1445                            PACKET_READ_CHOMP_NEWLINE |
1446                            PACKET_READ_DIE_ON_ERR_PACKET);
1447         if (git_env_bool("GIT_TEST_SIDEBAND_ALL", 1) &&
1448             server_supports_feature("fetch", "sideband-all", 0)) {
1449                 reader.use_sideband = 1;
1450                 reader.me = "fetch-pack";
1451         }
1452
1453         while (state != FETCH_DONE) {
1454                 switch (state) {
1455                 case FETCH_CHECK_LOCAL:
1456                         sort_ref_list(&ref, ref_compare_name);
1457                         QSORT(sought, nr_sought, cmp_ref_by_name);
1458
1459                         /* v2 supports these by default */
1460                         allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
1461                         use_sideband = 2;
1462                         if (args->depth > 0 || args->deepen_since || args->deepen_not)
1463                                 args->deepen = 1;
1464
1465                         /* Filter 'ref' by 'sought' and those that aren't local */
1466                         if (!args->no_dependents) {
1467                                 mark_complete_and_common_ref(negotiator, args, &ref);
1468                                 filter_refs(args, &ref, sought, nr_sought);
1469                                 if (everything_local(args, &ref))
1470                                         state = FETCH_DONE;
1471                                 else
1472                                         state = FETCH_SEND_REQUEST;
1473
1474                                 mark_tips(negotiator, args->negotiation_tips);
1475                                 for_each_cached_alternate(negotiator,
1476                                                           insert_one_alternate_object);
1477                         } else {
1478                                 filter_refs(args, &ref, sought, nr_sought);
1479                                 state = FETCH_SEND_REQUEST;
1480                         }
1481                         break;
1482                 case FETCH_SEND_REQUEST:
1483                         if (!negotiation_started) {
1484                                 negotiation_started = 1;
1485                                 trace2_region_enter("fetch-pack",
1486                                                     "negotiation_v2",
1487                                                     the_repository);
1488                         }
1489                         if (send_fetch_request(negotiator, fd[1], args, ref,
1490                                                &common,
1491                                                &haves_to_send, &in_vain,
1492                                                reader.use_sideband))
1493                                 state = FETCH_GET_PACK;
1494                         else
1495                                 state = FETCH_PROCESS_ACKS;
1496                         break;
1497                 case FETCH_PROCESS_ACKS:
1498                         /* Process ACKs/NAKs */
1499                         switch (process_acks(negotiator, &reader, &common)) {
1500                         case 2:
1501                                 state = FETCH_GET_PACK;
1502                                 break;
1503                         case 1:
1504                                 in_vain = 0;
1505                                 /* fallthrough */
1506                         default:
1507                                 state = FETCH_SEND_REQUEST;
1508                                 break;
1509                         }
1510                         break;
1511                 case FETCH_GET_PACK:
1512                         trace2_region_leave("fetch-pack",
1513                                             "negotiation_v2",
1514                                             the_repository);
1515                         /* Check for shallow-info section */
1516                         if (process_section_header(&reader, "shallow-info", 1))
1517                                 receive_shallow_info(args, &reader, shallows, si);
1518
1519                         if (process_section_header(&reader, "wanted-refs", 1))
1520                                 receive_wanted_refs(&reader, sought, nr_sought);
1521
1522                         /* get the pack */
1523                         process_section_header(&reader, "packfile", 0);
1524                         if (get_pack(args, fd, pack_lockfile, sought, nr_sought))
1525                                 die(_("git fetch-pack: fetch failed."));
1526
1527                         state = FETCH_DONE;
1528                         break;
1529                 case FETCH_DONE:
1530                         continue;
1531                 }
1532         }
1533
1534         if (negotiator)
1535                 negotiator->release(negotiator);
1536         oidset_clear(&common);
1537         return ref;
1538 }
1539
1540 static int fetch_pack_config_cb(const char *var, const char *value, void *cb)
1541 {
1542         if (strcmp(var, "fetch.fsck.skiplist") == 0) {
1543                 const char *path;
1544
1545                 if (git_config_pathname(&path, var, value))
1546                         return 1;
1547                 strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
1548                         fsck_msg_types.len ? ',' : '=', path);
1549                 free((char *)path);
1550                 return 0;
1551         }
1552
1553         if (skip_prefix(var, "fetch.fsck.", &var)) {
1554                 if (is_valid_msg_type(var, value))
1555                         strbuf_addf(&fsck_msg_types, "%c%s=%s",
1556                                 fsck_msg_types.len ? ',' : '=', var, value);
1557                 else
1558                         warning("Skipping unknown msg id '%s'", var);
1559                 return 0;
1560         }
1561
1562         return git_default_config(var, value, cb);
1563 }
1564
1565 static void fetch_pack_config(void)
1566 {
1567         git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
1568         git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
1569         git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
1570         git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
1571         git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
1572
1573         git_config(fetch_pack_config_cb, NULL);
1574 }
1575
1576 static void fetch_pack_setup(void)
1577 {
1578         static int did_setup;
1579         if (did_setup)
1580                 return;
1581         fetch_pack_config();
1582         if (0 <= transfer_unpack_limit)
1583                 unpack_limit = transfer_unpack_limit;
1584         else if (0 <= fetch_unpack_limit)
1585                 unpack_limit = fetch_unpack_limit;
1586         did_setup = 1;
1587 }
1588
1589 static int remove_duplicates_in_refs(struct ref **ref, int nr)
1590 {
1591         struct string_list names = STRING_LIST_INIT_NODUP;
1592         int src, dst;
1593
1594         for (src = dst = 0; src < nr; src++) {
1595                 struct string_list_item *item;
1596                 item = string_list_insert(&names, ref[src]->name);
1597                 if (item->util)
1598                         continue; /* already have it */
1599                 item->util = ref[src];
1600                 if (src != dst)
1601                         ref[dst] = ref[src];
1602                 dst++;
1603         }
1604         for (src = dst; src < nr; src++)
1605                 ref[src] = NULL;
1606         string_list_clear(&names, 0);
1607         return dst;
1608 }
1609
1610 static void update_shallow(struct fetch_pack_args *args,
1611                            struct ref **sought, int nr_sought,
1612                            struct shallow_info *si)
1613 {
1614         struct oid_array ref = OID_ARRAY_INIT;
1615         int *status;
1616         int i;
1617
1618         if (args->deepen && alternate_shallow_file) {
1619                 if (*alternate_shallow_file == '\0') { /* --unshallow */
1620                         unlink_or_warn(git_path_shallow(the_repository));
1621                         rollback_lock_file(&shallow_lock);
1622                 } else
1623                         commit_lock_file(&shallow_lock);
1624                 alternate_shallow_file = NULL;
1625                 return;
1626         }
1627
1628         if (!si->shallow || !si->shallow->nr)
1629                 return;
1630
1631         if (args->cloning) {
1632                 /*
1633                  * remote is shallow, but this is a clone, there are
1634                  * no objects in repo to worry about. Accept any
1635                  * shallow points that exist in the pack (iow in repo
1636                  * after get_pack() and reprepare_packed_git())
1637                  */
1638                 struct oid_array extra = OID_ARRAY_INIT;
1639                 struct object_id *oid = si->shallow->oid;
1640                 for (i = 0; i < si->shallow->nr; i++)
1641                         if (has_object_file(&oid[i]))
1642                                 oid_array_append(&extra, &oid[i]);
1643                 if (extra.nr) {
1644                         setup_alternate_shallow(&shallow_lock,
1645                                                 &alternate_shallow_file,
1646                                                 &extra);
1647                         commit_lock_file(&shallow_lock);
1648                         alternate_shallow_file = NULL;
1649                 }
1650                 oid_array_clear(&extra);
1651                 return;
1652         }
1653
1654         if (!si->nr_ours && !si->nr_theirs)
1655                 return;
1656
1657         remove_nonexistent_theirs_shallow(si);
1658         if (!si->nr_ours && !si->nr_theirs)
1659                 return;
1660         for (i = 0; i < nr_sought; i++)
1661                 oid_array_append(&ref, &sought[i]->old_oid);
1662         si->ref = &ref;
1663
1664         if (args->update_shallow) {
1665                 /*
1666                  * remote is also shallow, .git/shallow may be updated
1667                  * so all refs can be accepted. Make sure we only add
1668                  * shallow roots that are actually reachable from new
1669                  * refs.
1670                  */
1671                 struct oid_array extra = OID_ARRAY_INIT;
1672                 struct object_id *oid = si->shallow->oid;
1673                 assign_shallow_commits_to_refs(si, NULL, NULL);
1674                 if (!si->nr_ours && !si->nr_theirs) {
1675                         oid_array_clear(&ref);
1676                         return;
1677                 }
1678                 for (i = 0; i < si->nr_ours; i++)
1679                         oid_array_append(&extra, &oid[si->ours[i]]);
1680                 for (i = 0; i < si->nr_theirs; i++)
1681                         oid_array_append(&extra, &oid[si->theirs[i]]);
1682                 setup_alternate_shallow(&shallow_lock,
1683                                         &alternate_shallow_file,
1684                                         &extra);
1685                 commit_lock_file(&shallow_lock);
1686                 oid_array_clear(&extra);
1687                 oid_array_clear(&ref);
1688                 alternate_shallow_file = NULL;
1689                 return;
1690         }
1691
1692         /*
1693          * remote is also shallow, check what ref is safe to update
1694          * without updating .git/shallow
1695          */
1696         status = xcalloc(nr_sought, sizeof(*status));
1697         assign_shallow_commits_to_refs(si, NULL, status);
1698         if (si->nr_ours || si->nr_theirs) {
1699                 for (i = 0; i < nr_sought; i++)
1700                         if (status[i])
1701                                 sought[i]->status = REF_STATUS_REJECT_SHALLOW;
1702         }
1703         free(status);
1704         oid_array_clear(&ref);
1705 }
1706
1707 static int iterate_ref_map(void *cb_data, struct object_id *oid)
1708 {
1709         struct ref **rm = cb_data;
1710         struct ref *ref = *rm;
1711
1712         if (!ref)
1713                 return -1; /* end of the list */
1714         *rm = ref->next;
1715         oidcpy(oid, &ref->old_oid);
1716         return 0;
1717 }
1718
1719 struct ref *fetch_pack(struct fetch_pack_args *args,
1720                        int fd[],
1721                        const struct ref *ref,
1722                        struct ref **sought, int nr_sought,
1723                        struct oid_array *shallow,
1724                        char **pack_lockfile,
1725                        enum protocol_version version)
1726 {
1727         struct ref *ref_cpy;
1728         struct shallow_info si;
1729         struct oid_array shallows_scratch = OID_ARRAY_INIT;
1730
1731         fetch_pack_setup();
1732         if (nr_sought)
1733                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
1734
1735         if (args->no_dependents && !args->filter_options.choice) {
1736                 /*
1737                  * The protocol does not support requesting that only the
1738                  * wanted objects be sent, so approximate this by setting a
1739                  * "blob:none" filter if no filter is already set. This works
1740                  * for all object types: note that wanted blobs will still be
1741                  * sent because they are directly specified as a "want".
1742                  *
1743                  * NEEDSWORK: Add an option in the protocol to request that
1744                  * only the wanted objects be sent, and implement it.
1745                  */
1746                 parse_list_objects_filter(&args->filter_options, "blob:none");
1747         }
1748
1749         if (version != protocol_v2 && !ref) {
1750                 packet_flush(fd[1]);
1751                 die(_("no matching remote head"));
1752         }
1753         if (version == protocol_v2) {
1754                 if (shallow->nr)
1755                         BUG("Protocol V2 does not provide shallows at this point in the fetch");
1756                 memset(&si, 0, sizeof(si));
1757                 ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
1758                                            &shallows_scratch, &si,
1759                                            pack_lockfile);
1760         } else {
1761                 prepare_shallow_info(&si, shallow);
1762                 ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
1763                                         &si, pack_lockfile);
1764         }
1765         reprepare_packed_git(the_repository);
1766
1767         if (!args->cloning && args->deepen) {
1768                 struct check_connected_options opt = CHECK_CONNECTED_INIT;
1769                 struct ref *iterator = ref_cpy;
1770                 opt.shallow_file = alternate_shallow_file;
1771                 if (args->deepen)
1772                         opt.is_deepening_fetch = 1;
1773                 if (check_connected(iterate_ref_map, &iterator, &opt)) {
1774                         error(_("remote did not send all necessary objects"));
1775                         free_refs(ref_cpy);
1776                         ref_cpy = NULL;
1777                         rollback_lock_file(&shallow_lock);
1778                         goto cleanup;
1779                 }
1780                 args->connectivity_checked = 1;
1781         }
1782
1783         update_shallow(args, sought, nr_sought, &si);
1784 cleanup:
1785         clear_shallow_info(&si);
1786         oid_array_clear(&shallows_scratch);
1787         return ref_cpy;
1788 }
1789
1790 int report_unmatched_refs(struct ref **sought, int nr_sought)
1791 {
1792         int i, ret = 0;
1793
1794         for (i = 0; i < nr_sought; i++) {
1795                 if (!sought[i])
1796                         continue;
1797                 switch (sought[i]->match_status) {
1798                 case REF_MATCHED:
1799                         continue;
1800                 case REF_NOT_MATCHED:
1801                         error(_("no such remote ref %s"), sought[i]->name);
1802                         break;
1803                 case REF_UNADVERTISED_NOT_ALLOWED:
1804                         error(_("Server does not allow request for unadvertised object %s"),
1805                               sought[i]->name);
1806                         break;
1807                 }
1808                 ret = 1;
1809         }
1810         return ret;
1811 }