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         trace2_region_enter("fetch-pack", "parse_remote_refs_and_find_cutoff", NULL);
 673         for (ref = *refs; ref; ref = ref->next) {
 674                 struct object *o;
 675
 676                 if (!has_object_file_with_flags(&ref->old_oid,
 677                                                 OBJECT_INFO_QUICK |
 678                                                         OBJECT_INFO_SKIP_FETCH_OBJECT))
 679                         continue;
 680                 o = parse_object(the_repository, &ref->old_oid);
 681                 if (!o)
 682                         continue;
 683
 684                 /*
 685                  * We already have it -- which may mean that we were
 686                  * in sync with the other side at some time after
 687                  * that (it is OK if we guess wrong here).
 688                  */
 689                 if (o->type == OBJ_COMMIT) {
 690                         struct commit *commit = (struct commit *)o;
 691                         if (!cutoff || cutoff < commit->date)
 692                                 cutoff = commit->date;
 693                 }
 694         }
 695         trace2_region_leave("fetch-pack", "parse_remote_refs_and_find_cutoff", NULL);
 696
 697         /*
 698          * This block marks all local refs as COMPLETE, and then recursively marks all
 699          * parents of those refs as COMPLETE.
 700          */
 701         trace2_region_enter("fetch-pack", "mark_complete_local_refs", NULL);
 702         if (!args->deepen) {
 703                 for_each_ref(mark_complete_oid, NULL);
 704                 for_each_cached_alternate(NULL, mark_alternate_complete);
 705                 commit_list_sort_by_date(&complete);
 706                 if (cutoff)
 707                         mark_recent_complete_commits(args, cutoff);
 708         }
 709         trace2_region_leave("fetch-pack", "mark_complete_local_refs", NULL);
 710
 711         /*
 712          * Mark all complete remote refs as common refs.
 713          * Don't mark them common yet; the server has to be told so first.
 714          */
 715         trace2_region_enter("fetch-pack", "mark_common_remote_refs", NULL);
 716         for (ref = *refs; ref; ref = ref->next) {
 717                 struct object *o = deref_tag(the_repository,
 718                                              lookup_object(the_repository,
 719                                              &ref->old_oid),
 720                                              NULL, 0);
 721
 722                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 723                         continue;
 724
 725                 negotiator->known_common(negotiator,
 726                                          (struct commit *)o);
 727         }
 728         trace2_region_leave("fetch-pack", "mark_common_remote_refs", NULL);
 729
 730         save_commit_buffer = old_save_commit_buffer;
 731 }
 732
 733 /*
 734  * Returns 1 if every object pointed to by the given remote refs is available
 735  * locally and reachable from a local ref, and 0 otherwise.
 736  */
 737 static int everything_local(struct fetch_pack_args *args,
 738                             struct ref **refs)
 739 {
 740         struct ref *ref;
 741         int retval;
 742
 743         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 744                 const struct object_id *remote = &ref->old_oid;
 745                 struct object *o;
 746
 747                 o = lookup_object(the_repository, remote);
 748                 if (!o || !(o->flags & COMPLETE)) {
 749                         retval = 0;
 750                         print_verbose(args, "want %s (%s)", oid_to_hex(remote),
 751                                       ref->name);
 752                         continue;
 753                 }
 754                 print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
 755                               ref->name);
 756         }
 757
 758         return retval;
 759 }
 760
 761 static int sideband_demux(int in, int out, void *data)
 762 {
 763         int *xd = data;
 764         int ret;
 765
 766         ret = recv_sideband("fetch-pack", xd[0], out);
 767         close(out);
 768         return ret;
 769 }
 770
 771 static void write_promisor_file(const char *keep_name,
 772                                 struct ref **sought, int nr_sought)
 773 {
 774         struct strbuf promisor_name = STRBUF_INIT;
 775         int suffix_stripped;
 776         FILE *output;
 777         int i;
 778
 779         strbuf_addstr(&promisor_name, keep_name);
 780         suffix_stripped = strbuf_strip_suffix(&promisor_name, ".keep");
 781         if (!suffix_stripped)
 782                 BUG("name of pack lockfile should end with .keep (was '%s')",
 783                     keep_name);
 784         strbuf_addstr(&promisor_name, ".promisor");
 785
 786         output = xfopen(promisor_name.buf, "w");
 787         for (i = 0; i < nr_sought; i++)
 788                 fprintf(output, "%s %s\n", oid_to_hex(&sought[i]->old_oid),
 789                         sought[i]->name);
 790         fclose(output);
 791
 792         strbuf_release(&promisor_name);
 793 }
 794
 795 static int get_pack(struct fetch_pack_args *args,
 796                     int xd[2], char **pack_lockfile,
 797                     struct ref **sought, int nr_sought)
 798 {
 799         struct async demux;
 800         int do_keep = args->keep_pack;
 801         const char *cmd_name;
 802         struct pack_header header;
 803         int pass_header = 0;
 804         struct child_process cmd = CHILD_PROCESS_INIT;
 805         int ret;
 806
 807         memset(&demux, 0, sizeof(demux));
 808         if (use_sideband) {
 809                 /* xd[] is talking with upload-pack; subprocess reads from
 810                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 811                  * through demux->out.
 812                  */
 813                 demux.proc = sideband_demux;
 814                 demux.data = xd;
 815                 demux.out = -1;
 816                 demux.isolate_sigpipe = 1;
 817                 if (start_async(&demux))
 818                         die(_("fetch-pack: unable to fork off sideband demultiplexer"));
 819         }
 820         else
 821                 demux.out = xd[0];
 822
 823         if (!args->keep_pack && unpack_limit) {
 824
 825                 if (read_pack_header(demux.out, &header))
 826                         die(_("protocol error: bad pack header"));
 827                 pass_header = 1;
 828                 if (ntohl(header.hdr_entries) < unpack_limit)
 829                         do_keep = 0;
 830                 else
 831                         do_keep = 1;
 832         }
 833
 834         if (alternate_shallow_file) {
 835                 argv_array_push(&cmd.args, "--shallow-file");
 836                 argv_array_push(&cmd.args, alternate_shallow_file);
 837         }
 838
 839         if (do_keep || args->from_promisor) {
 840                 if (pack_lockfile)
 841                         cmd.out = -1;
 842                 cmd_name = "index-pack";
 843                 argv_array_push(&cmd.args, cmd_name);
 844                 argv_array_push(&cmd.args, "--stdin");
 845                 if (!args->quiet && !args->no_progress)
 846                         argv_array_push(&cmd.args, "-v");
 847                 if (args->use_thin_pack)
 848                         argv_array_push(&cmd.args, "--fix-thin");
 849                 if (do_keep && (args->lock_pack || unpack_limit)) {
 850                         char hostname[HOST_NAME_MAX + 1];
 851                         if (xgethostname(hostname, sizeof(hostname)))
 852                                 xsnprintf(hostname, sizeof(hostname), "localhost");
 853                         argv_array_pushf(&cmd.args,
 854                                         "--keep=fetch-pack %"PRIuMAX " on %s",
 855                                         (uintmax_t)getpid(), hostname);
 856                 }
 857                 if (args->check_self_contained_and_connected)
 858                         argv_array_push(&cmd.args, "--check-self-contained-and-connected");
 859                 /*
 860                  * If we're obtaining the filename of a lockfile, we'll use
 861                  * that filename to write a .promisor file with more
 862                  * information below. If not, we need index-pack to do it for
 863                  * us.
 864                  */
 865                 if (!(do_keep && pack_lockfile) && args->from_promisor)
 866                         argv_array_push(&cmd.args, "--promisor");
 867         }
 868         else {
 869                 cmd_name = "unpack-objects";
 870                 argv_array_push(&cmd.args, cmd_name);
 871                 if (args->quiet || args->no_progress)
 872                         argv_array_push(&cmd.args, "-q");
 873                 args->check_self_contained_and_connected = 0;
 874         }
 875
 876         if (pass_header)
 877                 argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
 878                                  ntohl(header.hdr_version),
 879                                  ntohl(header.hdr_entries));
 880         if (fetch_fsck_objects >= 0
 881             ? fetch_fsck_objects
 882             : transfer_fsck_objects >= 0
 883             ? transfer_fsck_objects
 884             : 0) {
 885                 if (args->from_promisor)
 886                         /*
 887                          * We cannot use --strict in index-pack because it
 888                          * checks both broken objects and links, but we only
 889                          * want to check for broken objects.
 890                          */
 891                         argv_array_push(&cmd.args, "--fsck-objects");
 892                 else
 893                         argv_array_pushf(&cmd.args, "--strict%s",
 894                                          fsck_msg_types.buf);
 895         }
 896
 897         cmd.in = demux.out;
 898         cmd.git_cmd = 1;
 899         if (start_command(&cmd))
 900                 die(_("fetch-pack: unable to fork off %s"), cmd_name);
 901         if (do_keep && pack_lockfile) {
 902                 *pack_lockfile = index_pack_lockfile(cmd.out);
 903                 close(cmd.out);
 904         }
 905
 906         if (!use_sideband)
 907                 /* Closed by start_command() */
 908                 xd[0] = -1;
 909
 910         ret = finish_command(&cmd);
 911         if (!ret || (args->check_self_contained_and_connected && ret == 1))
 912                 args->self_contained_and_connected =
 913                         args->check_self_contained_and_connected &&
 914                         ret == 0;
 915         else
 916                 die(_("%s failed"), cmd_name);
 917         if (use_sideband && finish_async(&demux))
 918                 die(_("error in sideband demultiplexer"));
 919
 920         /*
 921          * Now that index-pack has succeeded, write the promisor file using the
 922          * obtained .keep filename if necessary
 923          */
 924         if (do_keep && pack_lockfile && args->from_promisor)
 925                 write_promisor_file(*pack_lockfile, sought, nr_sought);
 926
 927         return 0;
 928 }
 929
 930 static int cmp_ref_by_name(const void *a_, const void *b_)
 931 {
 932         const struct ref *a = *((const struct ref **)a_);
 933         const struct ref *b = *((const struct ref **)b_);
 934         return strcmp(a->name, b->name);
 935 }
 936
 937 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 938                                  int fd[2],
 939                                  const struct ref *orig_ref,
 940                                  struct ref **sought, int nr_sought,
 941                                  struct shallow_info *si,
 942                                  char **pack_lockfile)
 943 {
 944         struct repository *r = the_repository;
 945         struct ref *ref = copy_ref_list(orig_ref);
 946         struct object_id oid;
 947         const char *agent_feature;
 948         int agent_len;
 949         struct fetch_negotiator negotiator_alloc;
 950         struct fetch_negotiator *negotiator;
 951
 952         if (args->no_dependents) {
 953                 negotiator = NULL;
 954         } else {
 955                 negotiator = &negotiator_alloc;
 956                 fetch_negotiator_init(r, negotiator);
 957         }
 958
 959         sort_ref_list(&ref, ref_compare_name);
 960         QSORT(sought, nr_sought, cmp_ref_by_name);
 961
 962         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 963                 agent_supported = 1;
 964                 if (agent_len)
 965                         print_verbose(args, _("Server version is %.*s"),
 966                                       agent_len, agent_feature);
 967         }
 968
 969         if (server_supports("shallow"))
 970                 print_verbose(args, _("Server supports %s"), "shallow");
 971         else if (args->depth > 0 || is_repository_shallow(r))
 972                 die(_("Server does not support shallow clients"));
 973         if (args->depth > 0 || args->deepen_since || args->deepen_not)
 974                 args->deepen = 1;
 975         if (server_supports("multi_ack_detailed")) {
 976                 print_verbose(args, _("Server supports %s"), "multi_ack_detailed");
 977                 multi_ack = 2;
 978                 if (server_supports("no-done")) {
 979                         print_verbose(args, _("Server supports %s"), "no-done");
 980                         if (args->stateless_rpc)
 981                                 no_done = 1;
 982                 }
 983         }
 984         else if (server_supports("multi_ack")) {
 985                 print_verbose(args, _("Server supports %s"), "multi_ack");
 986                 multi_ack = 1;
 987         }
 988         if (server_supports("side-band-64k")) {
 989                 print_verbose(args, _("Server supports %s"), "side-band-64k");
 990                 use_sideband = 2;
 991         }
 992         else if (server_supports("side-band")) {
 993                 print_verbose(args, _("Server supports %s"), "side-band");
 994                 use_sideband = 1;
 995         }
 996         if (server_supports("allow-tip-sha1-in-want")) {
 997                 print_verbose(args, _("Server supports %s"), "allow-tip-sha1-in-want");
 998                 allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
 999         }
1000         if (server_supports("allow-reachable-sha1-in-want")) {
1001                 print_verbose(args, _("Server supports %s"), "allow-reachable-sha1-in-want");
1002                 allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
1003         }
1004         if (server_supports("thin-pack"))
1005                 print_verbose(args, _("Server supports %s"), "thin-pack");
1006         else
1007                 args->use_thin_pack = 0;
1008         if (server_supports("no-progress"))
1009                 print_verbose(args, _("Server supports %s"), "no-progress");
1010         else
1011                 args->no_progress = 0;
1012         if (server_supports("include-tag"))
1013                 print_verbose(args, _("Server supports %s"), "include-tag");
1014         else
1015                 args->include_tag = 0;
1016         if (server_supports("ofs-delta"))
1017                 print_verbose(args, _("Server supports %s"), "ofs-delta");
1018         else
1019                 prefer_ofs_delta = 0;
1020
1021         if (server_supports("filter")) {
1022                 server_supports_filtering = 1;
1023                 print_verbose(args, _("Server supports %s"), "filter");
1024         } else if (args->filter_options.choice) {
1025                 warning("filtering not recognized by server, ignoring");
1026         }
1027
1028         if (server_supports("deepen-since")) {
1029                 print_verbose(args, _("Server supports %s"), "deepen-since");
1030                 deepen_since_ok = 1;
1031         } else if (args->deepen_since)
1032                 die(_("Server does not support --shallow-since"));
1033         if (server_supports("deepen-not")) {
1034                 print_verbose(args, _("Server supports %s"), "deepen-not");
1035                 deepen_not_ok = 1;
1036         } else if (args->deepen_not)
1037                 die(_("Server does not support --shallow-exclude"));
1038         if (server_supports("deepen-relative"))
1039                 print_verbose(args, _("Server supports %s"), "deepen-relative");
1040         else if (args->deepen_relative)
1041                 die(_("Server does not support --deepen"));
1042
1043         if (!args->no_dependents) {
1044                 mark_complete_and_common_ref(negotiator, args, &ref);
1045                 filter_refs(args, &ref, sought, nr_sought);
1046                 if (everything_local(args, &ref)) {
1047                         packet_flush(fd[1]);
1048                         goto all_done;
1049                 }
1050         } else {
1051                 filter_refs(args, &ref, sought, nr_sought);
1052         }
1053         if (find_common(negotiator, args, fd, &oid, ref) < 0)
1054                 if (!args->keep_pack)
1055                         /* When cloning, it is not unusual to have
1056                          * no common commit.
1057                          */
1058                         warning(_("no common commits"));
1059
1060         if (args->stateless_rpc)
1061                 packet_flush(fd[1]);
1062         if (args->deepen)
1063                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
1064                                         NULL);
1065         else if (si->nr_ours || si->nr_theirs)
1066                 alternate_shallow_file = setup_temporary_shallow(si->shallow);
1067         else
1068                 alternate_shallow_file = NULL;
1069         if (get_pack(args, fd, pack_lockfile, sought, nr_sought))
1070                 die(_("git fetch-pack: fetch failed."));
1071
1072  all_done:
1073         if (negotiator)
1074                 negotiator->release(negotiator);
1075         return ref;
1076 }
1077
1078 static void add_shallow_requests(struct strbuf *req_buf,
1079                                  const struct fetch_pack_args *args)
1080 {
1081         if (is_repository_shallow(the_repository))
1082                 write_shallow_commits(req_buf, 1, NULL);
1083         if (args->depth > 0)
1084                 packet_buf_write(req_buf, "deepen %d", args->depth);
1085         if (args->deepen_since) {
1086                 timestamp_t max_age = approxidate(args->deepen_since);
1087                 packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
1088         }
1089         if (args->deepen_not) {
1090                 int i;
1091                 for (i = 0; i < args->deepen_not->nr; i++) {
1092                         struct string_list_item *s = args->deepen_not->items + i;
1093                         packet_buf_write(req_buf, "deepen-not %s", s->string);
1094                 }
1095         }
1096         if (args->deepen_relative)
1097                 packet_buf_write(req_buf, "deepen-relative\n");
1098 }
1099
1100 static void add_wants(int no_dependents, const struct ref *wants, struct strbuf *req_buf)
1101 {
1102         int use_ref_in_want = server_supports_feature("fetch", "ref-in-want", 0);
1103
1104         for ( ; wants ; wants = wants->next) {
1105                 const struct object_id *remote = &wants->old_oid;
1106                 struct object *o;
1107
1108                 /*
1109                  * If that object is complete (i.e. it is an ancestor of a
1110                  * local ref), we tell them we have it but do not have to
1111                  * tell them about its ancestors, which they already know
1112                  * about.
1113                  *
1114                  * We use lookup_object here because we are only
1115                  * interested in the case we *know* the object is
1116                  * reachable and we have already scanned it.
1117                  *
1118                  * Do this only if args->no_dependents is false (if it is true,
1119                  * we cannot trust the object flags).
1120                  */
1121                 if (!no_dependents &&
1122                     ((o = lookup_object(the_repository, remote)) != NULL) &&
1123                     (o->flags & COMPLETE)) {
1124                         continue;
1125                 }
1126
1127                 if (!use_ref_in_want || wants->exact_oid)
1128                         packet_buf_write(req_buf, "want %s\n", oid_to_hex(remote));
1129                 else
1130                         packet_buf_write(req_buf, "want-ref %s\n", wants->name);
1131         }
1132 }
1133
1134 static void add_common(struct strbuf *req_buf, struct oidset *common)
1135 {
1136         struct oidset_iter iter;
1137         const struct object_id *oid;
1138         oidset_iter_init(common, &iter);
1139
1140         while ((oid = oidset_iter_next(&iter))) {
1141                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1142         }
1143 }
1144
1145 static int add_haves(struct fetch_negotiator *negotiator,
1146                      struct strbuf *req_buf,
1147                      int *haves_to_send, int *in_vain)
1148 {
1149         int ret = 0;
1150         int haves_added = 0;
1151         const struct object_id *oid;
1152
1153         while ((oid = negotiator->next(negotiator))) {
1154                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1155                 if (++haves_added >= *haves_to_send)
1156                         break;
1157         }
1158
1159         *in_vain += haves_added;
1160         if (!haves_added || *in_vain >= MAX_IN_VAIN) {
1161                 /* Send Done */
1162                 packet_buf_write(req_buf, "done\n");
1163                 ret = 1;
1164         }
1165
1166         /* Increase haves to send on next round */
1167         *haves_to_send = next_flush(1, *haves_to_send);
1168
1169         return ret;
1170 }
1171
1172 static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
1173                               struct fetch_pack_args *args,
1174                               const struct ref *wants, struct oidset *common,
1175                               int *haves_to_send, int *in_vain,
1176                               int sideband_all)
1177 {
1178         int ret = 0;
1179         struct strbuf req_buf = STRBUF_INIT;
1180
1181         if (server_supports_v2("fetch", 1))
1182                 packet_buf_write(&req_buf, "command=fetch");
1183         if (server_supports_v2("agent", 0))
1184                 packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
1185         if (args->server_options && args->server_options->nr &&
1186             server_supports_v2("server-option", 1)) {
1187                 int i;
1188                 for (i = 0; i < args->server_options->nr; i++)
1189                         packet_buf_write(&req_buf, "server-option=%s",
1190                                          args->server_options->items[i].string);
1191         }
1192
1193         packet_buf_delim(&req_buf);
1194         if (args->use_thin_pack)
1195                 packet_buf_write(&req_buf, "thin-pack");
1196         if (args->no_progress)
1197                 packet_buf_write(&req_buf, "no-progress");
1198         if (args->include_tag)
1199                 packet_buf_write(&req_buf, "include-tag");
1200         if (prefer_ofs_delta)
1201                 packet_buf_write(&req_buf, "ofs-delta");
1202         if (sideband_all)
1203                 packet_buf_write(&req_buf, "sideband-all");
1204
1205         /* Add shallow-info and deepen request */
1206         if (server_supports_feature("fetch", "shallow", 0))
1207                 add_shallow_requests(&req_buf, args);
1208         else if (is_repository_shallow(the_repository) || args->deepen)
1209                 die(_("Server does not support shallow requests"));
1210
1211         /* Add filter */
1212         if (server_supports_feature("fetch", "filter", 0) &&
1213             args->filter_options.choice) {
1214                 const char *spec =
1215                         expand_list_objects_filter_spec(&args->filter_options);
1216                 print_verbose(args, _("Server supports filter"));
1217                 packet_buf_write(&req_buf, "filter %s", spec);
1218         } else if (args->filter_options.choice) {
1219                 warning("filtering not recognized by server, ignoring");
1220         }
1221
1222         /* add wants */
1223         add_wants(args->no_dependents, wants, &req_buf);
1224
1225         if (args->no_dependents) {
1226                 packet_buf_write(&req_buf, "done");
1227                 ret = 1;
1228         } else {
1229                 /* Add all of the common commits we've found in previous rounds */
1230                 add_common(&req_buf, common);
1231
1232                 /* Add initial haves */
1233                 ret = add_haves(negotiator, &req_buf, haves_to_send, in_vain);
1234         }
1235
1236         /* Send request */
1237         packet_buf_flush(&req_buf);
1238         if (write_in_full(fd_out, req_buf.buf, req_buf.len) < 0)
1239                 die_errno(_("unable to write request to remote"));
1240
1241         strbuf_release(&req_buf);
1242         return ret;
1243 }
1244
1245 /*
1246  * Processes a section header in a server's response and checks if it matches
1247  * `section`.  If the value of `peek` is 1, the header line will be peeked (and
1248  * not consumed); if 0, the line will be consumed and the function will die if
1249  * the section header doesn't match what was expected.
1250  */
1251 static int process_section_header(struct packet_reader *reader,
1252                                   const char *section, int peek)
1253 {
1254         int ret;
1255
1256         if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
1257                 die(_("error reading section header '%s'"), section);
1258
1259         ret = !strcmp(reader->line, section);
1260
1261         if (!peek) {
1262                 if (!ret)
1263                         die(_("expected '%s', received '%s'"),
1264                             section, reader->line);
1265                 packet_reader_read(reader);
1266         }
1267
1268         return ret;
1269 }
1270
1271 static int process_acks(struct fetch_negotiator *negotiator,
1272                         struct packet_reader *reader,
1273                         struct oidset *common)
1274 {
1275         /* received */
1276         int received_ready = 0;
1277         int received_ack = 0;
1278
1279         process_section_header(reader, "acknowledgments", 0);
1280         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1281                 const char *arg;
1282
1283                 if (!strcmp(reader->line, "NAK"))
1284                         continue;
1285
1286                 if (skip_prefix(reader->line, "ACK ", &arg)) {
1287                         struct object_id oid;
1288                         if (!get_oid_hex(arg, &oid)) {
1289                                 struct commit *commit;
1290                                 oidset_insert(common, &oid);
1291                                 commit = lookup_commit(the_repository, &oid);
1292                                 if (negotiator)
1293                                         negotiator->ack(negotiator, commit);
1294                         }
1295                         continue;
1296                 }
1297
1298                 if (!strcmp(reader->line, "ready")) {
1299                         received_ready = 1;
1300                         continue;
1301                 }
1302
1303                 die(_("unexpected acknowledgment line: '%s'"), reader->line);
1304         }
1305
1306         if (reader->status != PACKET_READ_FLUSH &&
1307             reader->status != PACKET_READ_DELIM)
1308                 die(_("error processing acks: %d"), reader->status);
1309
1310         /*
1311          * If an "acknowledgments" section is sent, a packfile is sent if and
1312          * only if "ready" was sent in this section. The other sections
1313          * ("shallow-info" and "wanted-refs") are sent only if a packfile is
1314          * sent. Therefore, a DELIM is expected if "ready" is sent, and a FLUSH
1315          * otherwise.
1316          */
1317         if (received_ready && reader->status != PACKET_READ_DELIM)
1318                 die(_("expected packfile to be sent after 'ready'"));
1319         if (!received_ready && reader->status != PACKET_READ_FLUSH)
1320                 die(_("expected no other sections to be sent after no 'ready'"));
1321
1322         /* return 0 if no common, 1 if there are common, or 2 if ready */
1323         return received_ready ? 2 : (received_ack ? 1 : 0);
1324 }
1325
1326 static void receive_shallow_info(struct fetch_pack_args *args,
1327                                  struct packet_reader *reader,
1328                                  struct oid_array *shallows,
1329                                  struct shallow_info *si)
1330 {
1331         int unshallow_received = 0;
1332
1333         process_section_header(reader, "shallow-info", 0);
1334         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1335                 const char *arg;
1336                 struct object_id oid;
1337
1338                 if (skip_prefix(reader->line, "shallow ", &arg)) {
1339                         if (get_oid_hex(arg, &oid))
1340                                 die(_("invalid shallow line: %s"), reader->line);
1341                         oid_array_append(shallows, &oid);
1342                         continue;
1343                 }
1344                 if (skip_prefix(reader->line, "unshallow ", &arg)) {
1345                         if (get_oid_hex(arg, &oid))
1346                                 die(_("invalid unshallow line: %s"), reader->line);
1347                         if (!lookup_object(the_repository, &oid))
1348                                 die(_("object not found: %s"), reader->line);
1349                         /* make sure that it is parsed as shallow */
1350                         if (!parse_object(the_repository, &oid))
1351                                 die(_("error in object: %s"), reader->line);
1352                         if (unregister_shallow(&oid))
1353                                 die(_("no shallow found: %s"), reader->line);
1354                         unshallow_received = 1;
1355                         continue;
1356                 }
1357                 die(_("expected shallow/unshallow, got %s"), reader->line);
1358         }
1359
1360         if (reader->status != PACKET_READ_FLUSH &&
1361             reader->status != PACKET_READ_DELIM)
1362                 die(_("error processing shallow info: %d"), reader->status);
1363
1364         if (args->deepen || unshallow_received) {
1365                 /*
1366                  * Treat these as shallow lines caused by our depth settings.
1367                  * In v0, these lines cannot cause refs to be rejected; do the
1368                  * same.
1369                  */
1370                 int i;
1371
1372                 for (i = 0; i < shallows->nr; i++)
1373                         register_shallow(the_repository, &shallows->oid[i]);
1374                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
1375                                         NULL);
1376                 args->deepen = 1;
1377         } else if (shallows->nr) {
1378                 /*
1379                  * Treat these as shallow lines caused by the remote being
1380                  * shallow. In v0, remote refs that reach these objects are
1381                  * rejected (unless --update-shallow is set); do the same.
1382                  */
1383                 prepare_shallow_info(si, shallows);
1384                 if (si->nr_ours || si->nr_theirs)
1385                         alternate_shallow_file =
1386                                 setup_temporary_shallow(si->shallow);
1387                 else
1388                         alternate_shallow_file = NULL;
1389         } else {
1390                 alternate_shallow_file = NULL;
1391         }
1392 }
1393
1394 static int cmp_name_ref(const void *name, const void *ref)
1395 {
1396         return strcmp(name, (*(struct ref **)ref)->name);
1397 }
1398
1399 static void receive_wanted_refs(struct packet_reader *reader,
1400                                 struct ref **sought, int nr_sought)
1401 {
1402         process_section_header(reader, "wanted-refs", 0);
1403         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1404                 struct object_id oid;
1405                 const char *end;
1406                 struct ref **found;
1407
1408                 if (parse_oid_hex(reader->line, &oid, &end) || *end++ != ' ')
1409                         die(_("expected wanted-ref, got '%s'"), reader->line);
1410
1411                 found = bsearch(end, sought, nr_sought, sizeof(*sought),
1412                                 cmp_name_ref);
1413                 if (!found)
1414                         die(_("unexpected wanted-ref: '%s'"), reader->line);
1415                 oidcpy(&(*found)->old_oid, &oid);
1416         }
1417
1418         if (reader->status != PACKET_READ_DELIM)
1419                 die(_("error processing wanted refs: %d"), reader->status);
1420 }
1421
1422 enum fetch_state {
1423         FETCH_CHECK_LOCAL = 0,
1424         FETCH_SEND_REQUEST,
1425         FETCH_PROCESS_ACKS,
1426         FETCH_GET_PACK,
1427         FETCH_DONE,
1428 };
1429
1430 static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
1431                                     int fd[2],
1432                                     const struct ref *orig_ref,
1433                                     struct ref **sought, int nr_sought,
1434                                     struct oid_array *shallows,
1435                                     struct shallow_info *si,
1436                                     char **pack_lockfile)
1437 {
1438         struct repository *r = the_repository;
1439         struct ref *ref = copy_ref_list(orig_ref);
1440         enum fetch_state state = FETCH_CHECK_LOCAL;
1441         struct oidset common = OIDSET_INIT;
1442         struct packet_reader reader;
1443         int in_vain = 0, negotiation_started = 0;
1444         int haves_to_send = INITIAL_FLUSH;
1445         struct fetch_negotiator negotiator_alloc;
1446         struct fetch_negotiator *negotiator;
1447
1448         if (args->no_dependents) {
1449                 negotiator = NULL;
1450         } else {
1451                 negotiator = &negotiator_alloc;
1452                 fetch_negotiator_init(r, negotiator);
1453         }
1454
1455         packet_reader_init(&reader, fd[0], NULL, 0,
1456                            PACKET_READ_CHOMP_NEWLINE |
1457                            PACKET_READ_DIE_ON_ERR_PACKET);
1458         if (git_env_bool("GIT_TEST_SIDEBAND_ALL", 1) &&
1459             server_supports_feature("fetch", "sideband-all", 0)) {
1460                 reader.use_sideband = 1;
1461                 reader.me = "fetch-pack";
1462         }
1463
1464         while (state != FETCH_DONE) {
1465                 switch (state) {
1466                 case FETCH_CHECK_LOCAL:
1467                         sort_ref_list(&ref, ref_compare_name);
1468                         QSORT(sought, nr_sought, cmp_ref_by_name);
1469
1470                         /* v2 supports these by default */
1471                         allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
1472                         use_sideband = 2;
1473                         if (args->depth > 0 || args->deepen_since || args->deepen_not)
1474                                 args->deepen = 1;
1475
1476                         /* Filter 'ref' by 'sought' and those that aren't local */
1477                         if (!args->no_dependents) {
1478                                 mark_complete_and_common_ref(negotiator, args, &ref);
1479                                 filter_refs(args, &ref, sought, nr_sought);
1480                                 if (everything_local(args, &ref))
1481                                         state = FETCH_DONE;
1482                                 else
1483                                         state = FETCH_SEND_REQUEST;
1484
1485                                 mark_tips(negotiator, args->negotiation_tips);
1486                                 for_each_cached_alternate(negotiator,
1487                                                           insert_one_alternate_object);
1488                         } else {
1489                                 filter_refs(args, &ref, sought, nr_sought);
1490                                 state = FETCH_SEND_REQUEST;
1491                         }
1492                         break;
1493                 case FETCH_SEND_REQUEST:
1494                         if (!negotiation_started) {
1495                                 negotiation_started = 1;
1496                                 trace2_region_enter("fetch-pack",
1497                                                     "negotiation_v2",
1498                                                     the_repository);
1499                         }
1500                         if (send_fetch_request(negotiator, fd[1], args, ref,
1501                                                &common,
1502                                                &haves_to_send, &in_vain,
1503                                                reader.use_sideband))
1504                                 state = FETCH_GET_PACK;
1505                         else
1506                                 state = FETCH_PROCESS_ACKS;
1507                         break;
1508                 case FETCH_PROCESS_ACKS:
1509                         /* Process ACKs/NAKs */
1510                         switch (process_acks(negotiator, &reader, &common)) {
1511                         case 2:
1512                                 state = FETCH_GET_PACK;
1513                                 break;
1514                         case 1:
1515                                 in_vain = 0;
1516                                 /* fallthrough */
1517                         default:
1518                                 state = FETCH_SEND_REQUEST;
1519                                 break;
1520                         }
1521                         break;
1522                 case FETCH_GET_PACK:
1523                         trace2_region_leave("fetch-pack",
1524                                             "negotiation_v2",
1525                                             the_repository);
1526                         /* Check for shallow-info section */
1527                         if (process_section_header(&reader, "shallow-info", 1))
1528                                 receive_shallow_info(args, &reader, shallows, si);
1529
1530                         if (process_section_header(&reader, "wanted-refs", 1))
1531                                 receive_wanted_refs(&reader, sought, nr_sought);
1532
1533                         /* get the pack */
1534                         process_section_header(&reader, "packfile", 0);
1535                         if (get_pack(args, fd, pack_lockfile, sought, nr_sought))
1536                                 die(_("git fetch-pack: fetch failed."));
1537
1538                         state = FETCH_DONE;
1539                         break;
1540                 case FETCH_DONE:
1541                         continue;
1542                 }
1543         }
1544
1545         if (negotiator)
1546                 negotiator->release(negotiator);
1547         oidset_clear(&common);
1548         return ref;
1549 }
1550
1551 static int fetch_pack_config_cb(const char *var, const char *value, void *cb)
1552 {
1553         if (strcmp(var, "fetch.fsck.skiplist") == 0) {
1554                 const char *path;
1555
1556                 if (git_config_pathname(&path, var, value))
1557                         return 1;
1558                 strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
1559                         fsck_msg_types.len ? ',' : '=', path);
1560                 free((char *)path);
1561                 return 0;
1562         }
1563
1564         if (skip_prefix(var, "fetch.fsck.", &var)) {
1565                 if (is_valid_msg_type(var, value))
1566                         strbuf_addf(&fsck_msg_types, "%c%s=%s",
1567                                 fsck_msg_types.len ? ',' : '=', var, value);
1568                 else
1569                         warning("Skipping unknown msg id '%s'", var);
1570                 return 0;
1571         }
1572
1573         return git_default_config(var, value, cb);
1574 }
1575
1576 static void fetch_pack_config(void)
1577 {
1578         git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
1579         git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
1580         git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
1581         git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
1582         git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
1583
1584         git_config(fetch_pack_config_cb, NULL);
1585 }
1586
1587 static void fetch_pack_setup(void)
1588 {
1589         static int did_setup;
1590         if (did_setup)
1591                 return;
1592         fetch_pack_config();
1593         if (0 <= transfer_unpack_limit)
1594                 unpack_limit = transfer_unpack_limit;
1595         else if (0 <= fetch_unpack_limit)
1596                 unpack_limit = fetch_unpack_limit;
1597         did_setup = 1;
1598 }
1599
1600 static int remove_duplicates_in_refs(struct ref **ref, int nr)
1601 {
1602         struct string_list names = STRING_LIST_INIT_NODUP;
1603         int src, dst;
1604
1605         for (src = dst = 0; src < nr; src++) {
1606                 struct string_list_item *item;
1607                 item = string_list_insert(&names, ref[src]->name);
1608                 if (item->util)
1609                         continue; /* already have it */
1610                 item->util = ref[src];
1611                 if (src != dst)
1612                         ref[dst] = ref[src];
1613                 dst++;
1614         }
1615         for (src = dst; src < nr; src++)
1616                 ref[src] = NULL;
1617         string_list_clear(&names, 0);
1618         return dst;
1619 }
1620
1621 static void update_shallow(struct fetch_pack_args *args,
1622                            struct ref **sought, int nr_sought,
1623                            struct shallow_info *si)
1624 {
1625         struct oid_array ref = OID_ARRAY_INIT;
1626         int *status;
1627         int i;
1628
1629         if (args->deepen && alternate_shallow_file) {
1630                 if (*alternate_shallow_file == '\0') { /* --unshallow */
1631                         unlink_or_warn(git_path_shallow(the_repository));
1632                         rollback_lock_file(&shallow_lock);
1633                 } else
1634                         commit_lock_file(&shallow_lock);
1635                 alternate_shallow_file = NULL;
1636                 return;
1637         }
1638
1639         if (!si->shallow || !si->shallow->nr)
1640                 return;
1641
1642         if (args->cloning) {
1643                 /*
1644                  * remote is shallow, but this is a clone, there are
1645                  * no objects in repo to worry about. Accept any
1646                  * shallow points that exist in the pack (iow in repo
1647                  * after get_pack() and reprepare_packed_git())
1648                  */
1649                 struct oid_array extra = OID_ARRAY_INIT;
1650                 struct object_id *oid = si->shallow->oid;
1651                 for (i = 0; i < si->shallow->nr; i++)
1652                         if (has_object_file(&oid[i]))
1653                                 oid_array_append(&extra, &oid[i]);
1654                 if (extra.nr) {
1655                         setup_alternate_shallow(&shallow_lock,
1656                                                 &alternate_shallow_file,
1657                                                 &extra);
1658                         commit_lock_file(&shallow_lock);
1659                         alternate_shallow_file = NULL;
1660                 }
1661                 oid_array_clear(&extra);
1662                 return;
1663         }
1664
1665         if (!si->nr_ours && !si->nr_theirs)
1666                 return;
1667
1668         remove_nonexistent_theirs_shallow(si);
1669         if (!si->nr_ours && !si->nr_theirs)
1670                 return;
1671         for (i = 0; i < nr_sought; i++)
1672                 oid_array_append(&ref, &sought[i]->old_oid);
1673         si->ref = &ref;
1674
1675         if (args->update_shallow) {
1676                 /*
1677                  * remote is also shallow, .git/shallow may be updated
1678                  * so all refs can be accepted. Make sure we only add
1679                  * shallow roots that are actually reachable from new
1680                  * refs.
1681                  */
1682                 struct oid_array extra = OID_ARRAY_INIT;
1683                 struct object_id *oid = si->shallow->oid;
1684                 assign_shallow_commits_to_refs(si, NULL, NULL);
1685                 if (!si->nr_ours && !si->nr_theirs) {
1686                         oid_array_clear(&ref);
1687                         return;
1688                 }
1689                 for (i = 0; i < si->nr_ours; i++)
1690                         oid_array_append(&extra, &oid[si->ours[i]]);
1691                 for (i = 0; i < si->nr_theirs; i++)
1692                         oid_array_append(&extra, &oid[si->theirs[i]]);
1693                 setup_alternate_shallow(&shallow_lock,
1694                                         &alternate_shallow_file,
1695                                         &extra);
1696                 commit_lock_file(&shallow_lock);
1697                 oid_array_clear(&extra);
1698                 oid_array_clear(&ref);
1699                 alternate_shallow_file = NULL;
1700                 return;
1701         }
1702
1703         /*
1704          * remote is also shallow, check what ref is safe to update
1705          * without updating .git/shallow
1706          */
1707         status = xcalloc(nr_sought, sizeof(*status));
1708         assign_shallow_commits_to_refs(si, NULL, status);
1709         if (si->nr_ours || si->nr_theirs) {
1710                 for (i = 0; i < nr_sought; i++)
1711                         if (status[i])
1712                                 sought[i]->status = REF_STATUS_REJECT_SHALLOW;
1713         }
1714         free(status);
1715         oid_array_clear(&ref);
1716 }
1717
1718 static int iterate_ref_map(void *cb_data, struct object_id *oid)
1719 {
1720         struct ref **rm = cb_data;
1721         struct ref *ref = *rm;
1722
1723         if (!ref)
1724                 return -1; /* end of the list */
1725         *rm = ref->next;
1726         oidcpy(oid, &ref->old_oid);
1727         return 0;
1728 }
1729
1730 struct ref *fetch_pack(struct fetch_pack_args *args,
1731                        int fd[],
1732                        const struct ref *ref,
1733                        struct ref **sought, int nr_sought,
1734                        struct oid_array *shallow,
1735                        char **pack_lockfile,
1736                        enum protocol_version version)
1737 {
1738         struct ref *ref_cpy;
1739         struct shallow_info si;
1740         struct oid_array shallows_scratch = OID_ARRAY_INIT;
1741
1742         fetch_pack_setup();
1743         if (nr_sought)
1744                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
1745
1746         if (args->no_dependents && !args->filter_options.choice) {
1747                 /*
1748                  * The protocol does not support requesting that only the
1749                  * wanted objects be sent, so approximate this by setting a
1750                  * "blob:none" filter if no filter is already set. This works
1751                  * for all object types: note that wanted blobs will still be
1752                  * sent because they are directly specified as a "want".
1753                  *
1754                  * NEEDSWORK: Add an option in the protocol to request that
1755                  * only the wanted objects be sent, and implement it.
1756                  */
1757                 parse_list_objects_filter(&args->filter_options, "blob:none");
1758         }
1759
1760         if (version != protocol_v2 && !ref) {
1761                 packet_flush(fd[1]);
1762                 die(_("no matching remote head"));
1763         }
1764         if (version == protocol_v2) {
1765                 if (shallow->nr)
1766                         BUG("Protocol V2 does not provide shallows at this point in the fetch");
1767                 memset(&si, 0, sizeof(si));
1768                 ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
1769                                            &shallows_scratch, &si,
1770                                            pack_lockfile);
1771         } else {
1772                 prepare_shallow_info(&si, shallow);
1773                 ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
1774                                         &si, pack_lockfile);
1775         }
1776         reprepare_packed_git(the_repository);
1777
1778         if (!args->cloning && args->deepen) {
1779                 struct check_connected_options opt = CHECK_CONNECTED_INIT;
1780                 struct ref *iterator = ref_cpy;
1781                 opt.shallow_file = alternate_shallow_file;
1782                 if (args->deepen)
1783                         opt.is_deepening_fetch = 1;
1784                 if (check_connected(iterate_ref_map, &iterator, &opt)) {
1785                         error(_("remote did not send all necessary objects"));
1786                         free_refs(ref_cpy);
1787                         ref_cpy = NULL;
1788                         rollback_lock_file(&shallow_lock);
1789                         goto cleanup;
1790                 }
1791                 args->connectivity_checked = 1;
1792         }
1793
1794         update_shallow(args, sought, nr_sought, &si);
1795 cleanup:
1796         clear_shallow_info(&si);
1797         oid_array_clear(&shallows_scratch);
1798         return ref_cpy;
1799 }
1800
1801 int report_unmatched_refs(struct ref **sought, int nr_sought)
1802 {
1803         int i, ret = 0;
1804
1805         for (i = 0; i < nr_sought; i++) {
1806                 if (!sought[i])
1807                         continue;
1808                 switch (sought[i]->match_status) {
1809                 case REF_MATCHED:
1810                         continue;
1811                 case REF_NOT_MATCHED:
1812                         error(_("no such remote ref %s"), sought[i]->name);
1813                         break;
1814                 case REF_UNADVERTISED_NOT_ALLOWED:
1815                         error(_("Server does not allow request for unadvertised object %s"),
1816                               sought[i]->name);
1817                         break;
1818                 }
1819                 ret = 1;
1820         }
1821         return ret;
1822 }