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 "oid-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 #include "shallow.h"
  26
  27 static int transfer_unpack_limit = -1;
  28 static int fetch_unpack_limit = -1;
  29 static int unpack_limit = 100;
  30 static int prefer_ofs_delta = 1;
  31 static int no_done;
  32 static int deepen_since_ok;
  33 static int deepen_not_ok;
  34 static int fetch_fsck_objects = -1;
  35 static int transfer_fsck_objects = -1;
  36 static int agent_supported;
  37 static int server_supports_filtering;
  38 static struct shallow_lock shallow_lock;
  39 static const char *alternate_shallow_file;
  40 static struct strbuf fsck_msg_types = STRBUF_INIT;
  41
  42 /* Remember to update object flag allocation in object.h */
  43 #define COMPLETE        (1U << 0)
  44 #define ALTERNATE       (1U << 1)
  45
  46 /*
  47  * After sending this many "have"s if we do not get any new ACK , we
  48  * give up traversing our history.
  49  */
  50 #define MAX_IN_VAIN 256
  51
  52 static int multi_ack, use_sideband;
  53 /* Allow specifying sha1 if it is a ref tip. */
  54 #define ALLOW_TIP_SHA1  01
  55 /* Allow request of a sha1 if it is reachable from a ref (possibly hidden ref). */
  56 #define ALLOW_REACHABLE_SHA1    02
  57 static unsigned int allow_unadvertised_object_request;
  58
  59 __attribute__((format (printf, 2, 3)))
  60 static inline void print_verbose(const struct fetch_pack_args *args,
  61                                  const char *fmt, ...)
  62 {
  63         va_list params;
  64
  65         if (!args->verbose)
  66                 return;
  67
  68         va_start(params, fmt);
  69         vfprintf(stderr, fmt, params);
  70         va_end(params);
  71         fputc('\n', stderr);
  72 }
  73
  74 struct alternate_object_cache {
  75         struct object **items;
  76         size_t nr, alloc;
  77 };
  78
  79 static void cache_one_alternate(const struct object_id *oid,
  80                                 void *vcache)
  81 {
  82         struct alternate_object_cache *cache = vcache;
  83         struct object *obj = parse_object(the_repository, oid);
  84
  85         if (!obj || (obj->flags & ALTERNATE))
  86                 return;
  87
  88         obj->flags |= ALTERNATE;
  89         ALLOC_GROW(cache->items, cache->nr + 1, cache->alloc);
  90         cache->items[cache->nr++] = obj;
  91 }
  92
  93 static void for_each_cached_alternate(struct fetch_negotiator *negotiator,
  94                                       void (*cb)(struct fetch_negotiator *,
  95                                                  struct object *))
  96 {
  97         static int initialized;
  98         static struct alternate_object_cache cache;
  99         size_t i;
 100
 101         if (!initialized) {
 102                 for_each_alternate_ref(cache_one_alternate, &cache);
 103                 initialized = 1;
 104         }
 105
 106         for (i = 0; i < cache.nr; i++)
 107                 cb(negotiator, cache.items[i]);
 108 }
 109
 110 static int rev_list_insert_ref(struct fetch_negotiator *negotiator,
 111                                const char *refname,
 112                                const struct object_id *oid)
 113 {
 114         struct object *o = deref_tag(the_repository,
 115                                      parse_object(the_repository, oid),
 116                                      refname, 0);
 117
 118         if (o && o->type == OBJ_COMMIT)
 119                 negotiator->add_tip(negotiator, (struct commit *)o);
 120
 121         return 0;
 122 }
 123
 124 static int rev_list_insert_ref_oid(const char *refname, const struct object_id *oid,
 125                                    int flag, void *cb_data)
 126 {
 127         return rev_list_insert_ref(cb_data, refname, oid);
 128 }
 129
 130 enum ack_type {
 131         NAK = 0,
 132         ACK,
 133         ACK_continue,
 134         ACK_common,
 135         ACK_ready
 136 };
 137
 138 static void consume_shallow_list(struct fetch_pack_args *args,
 139                                  struct packet_reader *reader)
 140 {
 141         if (args->stateless_rpc && args->deepen) {
 142                 /* If we sent a depth we will get back "duplicate"
 143                  * shallow and unshallow commands every time there
 144                  * is a block of have lines exchanged.
 145                  */
 146                 while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 147                         if (starts_with(reader->line, "shallow "))
 148                                 continue;
 149                         if (starts_with(reader->line, "unshallow "))
 150                                 continue;
 151                         die(_("git fetch-pack: expected shallow list"));
 152                 }
 153                 if (reader->status != PACKET_READ_FLUSH)
 154                         die(_("git fetch-pack: expected a flush packet after shallow list"));
 155         }
 156 }
 157
 158 static enum ack_type get_ack(struct packet_reader *reader,
 159                              struct object_id *result_oid)
 160 {
 161         int len;
 162         const char *arg;
 163
 164         if (packet_reader_read(reader) != PACKET_READ_NORMAL)
 165                 die(_("git fetch-pack: expected ACK/NAK, got a flush packet"));
 166         len = reader->pktlen;
 167
 168         if (!strcmp(reader->line, "NAK"))
 169                 return NAK;
 170         if (skip_prefix(reader->line, "ACK ", &arg)) {
 171                 const char *p;
 172                 if (!parse_oid_hex(arg, result_oid, &p)) {
 173                         len -= p - reader->line;
 174                         if (len < 1)
 175                                 return ACK;
 176                         if (strstr(p, "continue"))
 177                                 return ACK_continue;
 178                         if (strstr(p, "common"))
 179                                 return ACK_common;
 180                         if (strstr(p, "ready"))
 181                                 return ACK_ready;
 182                         return ACK;
 183                 }
 184         }
 185         die(_("git fetch-pack: expected ACK/NAK, got '%s'"), reader->line);
 186 }
 187
 188 static void send_request(struct fetch_pack_args *args,
 189                          int fd, struct strbuf *buf)
 190 {
 191         if (args->stateless_rpc) {
 192                 send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 193                 packet_flush(fd);
 194         } else {
 195                 if (write_in_full(fd, buf->buf, buf->len) < 0)
 196                         die_errno(_("unable to write to remote"));
 197         }
 198 }
 199
 200 static void insert_one_alternate_object(struct fetch_negotiator *negotiator,
 201                                         struct object *obj)
 202 {
 203         rev_list_insert_ref(negotiator, NULL, &obj->oid);
 204 }
 205
 206 #define INITIAL_FLUSH 16
 207 #define PIPESAFE_FLUSH 32
 208 #define LARGE_FLUSH 16384
 209
 210 static int next_flush(int stateless_rpc, int count)
 211 {
 212         if (stateless_rpc) {
 213                 if (count < LARGE_FLUSH)
 214                         count <<= 1;
 215                 else
 216                         count = count * 11 / 10;
 217         } else {
 218                 if (count < PIPESAFE_FLUSH)
 219                         count <<= 1;
 220                 else
 221                         count += PIPESAFE_FLUSH;
 222         }
 223         return count;
 224 }
 225
 226 static void mark_tips(struct fetch_negotiator *negotiator,
 227                       const struct oid_array *negotiation_tips)
 228 {
 229         int i;
 230
 231         if (!negotiation_tips) {
 232                 for_each_ref(rev_list_insert_ref_oid, negotiator);
 233                 return;
 234         }
 235
 236         for (i = 0; i < negotiation_tips->nr; i++)
 237                 rev_list_insert_ref(negotiator, NULL,
 238                                     &negotiation_tips->oid[i]);
 239         return;
 240 }
 241
 242 static int find_common(struct fetch_negotiator *negotiator,
 243                        struct fetch_pack_args *args,
 244                        int fd[2], struct object_id *result_oid,
 245                        struct ref *refs)
 246 {
 247         int fetching;
 248         int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 249         const struct object_id *oid;
 250         unsigned in_vain = 0;
 251         int got_continue = 0;
 252         int got_ready = 0;
 253         struct strbuf req_buf = STRBUF_INIT;
 254         size_t state_len = 0;
 255         struct packet_reader reader;
 256
 257         if (args->stateless_rpc && multi_ack == 1)
 258                 die(_("--stateless-rpc requires multi_ack_detailed"));
 259
 260         packet_reader_init(&reader, fd[0], NULL, 0,
 261                            PACKET_READ_CHOMP_NEWLINE |
 262                            PACKET_READ_DIE_ON_ERR_PACKET);
 263
 264         if (!args->no_dependents) {
 265                 mark_tips(negotiator, args->negotiation_tips);
 266                 for_each_cached_alternate(negotiator, insert_one_alternate_object);
 267         }
 268
 269         fetching = 0;
 270         for ( ; refs ; refs = refs->next) {
 271                 struct object_id *remote = &refs->old_oid;
 272                 const char *remote_hex;
 273                 struct object *o;
 274
 275                 /*
 276                  * If that object is complete (i.e. it is an ancestor of a
 277                  * local ref), we tell them we have it but do not have to
 278                  * tell them about its ancestors, which they already know
 279                  * about.
 280                  *
 281                  * We use lookup_object here because we are only
 282                  * interested in the case we *know* the object is
 283                  * reachable and we have already scanned it.
 284                  *
 285                  * Do this only if args->no_dependents is false (if it is true,
 286                  * we cannot trust the object flags).
 287                  */
 288                 if (!args->no_dependents &&
 289                     ((o = lookup_object(the_repository, remote)) != NULL) &&
 290                                 (o->flags & COMPLETE)) {
 291                         continue;
 292                 }
 293
 294                 remote_hex = oid_to_hex(remote);
 295                 if (!fetching) {
 296                         struct strbuf c = STRBUF_INIT;
 297                         if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 298                         if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 299                         if (no_done)            strbuf_addstr(&c, " no-done");
 300                         if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 301                         if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 302                         if (args->deepen_relative) strbuf_addstr(&c, " deepen-relative");
 303                         if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
 304                         if (args->no_progress)   strbuf_addstr(&c, " no-progress");
 305                         if (args->include_tag)   strbuf_addstr(&c, " include-tag");
 306                         if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 307                         if (deepen_since_ok)    strbuf_addstr(&c, " deepen-since");
 308                         if (deepen_not_ok)      strbuf_addstr(&c, " deepen-not");
 309                         if (agent_supported)    strbuf_addf(&c, " agent=%s",
 310                                                             git_user_agent_sanitized());
 311                         if (args->filter_options.choice)
 312                                 strbuf_addstr(&c, " filter");
 313                         packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 314                         strbuf_release(&c);
 315                 } else
 316                         packet_buf_write(&req_buf, "want %s\n", remote_hex);
 317                 fetching++;
 318         }
 319
 320         if (!fetching) {
 321                 strbuf_release(&req_buf);
 322                 packet_flush(fd[1]);
 323                 return 1;
 324         }
 325
 326         if (is_repository_shallow(the_repository))
 327                 write_shallow_commits(&req_buf, 1, NULL);
 328         if (args->depth > 0)
 329                 packet_buf_write(&req_buf, "deepen %d", args->depth);
 330         if (args->deepen_since) {
 331                 timestamp_t max_age = approxidate(args->deepen_since);
 332                 packet_buf_write(&req_buf, "deepen-since %"PRItime, max_age);
 333         }
 334         if (args->deepen_not) {
 335                 int i;
 336                 for (i = 0; i < args->deepen_not->nr; i++) {
 337                         struct string_list_item *s = args->deepen_not->items + i;
 338                         packet_buf_write(&req_buf, "deepen-not %s", s->string);
 339                 }
 340         }
 341         if (server_supports_filtering && args->filter_options.choice) {
 342                 const char *spec =
 343                         expand_list_objects_filter_spec(&args->filter_options);
 344                 packet_buf_write(&req_buf, "filter %s", spec);
 345         }
 346         packet_buf_flush(&req_buf);
 347         state_len = req_buf.len;
 348
 349         if (args->deepen) {
 350                 const char *arg;
 351                 struct object_id oid;
 352
 353                 send_request(args, fd[1], &req_buf);
 354                 while (packet_reader_read(&reader) == PACKET_READ_NORMAL) {
 355                         if (skip_prefix(reader.line, "shallow ", &arg)) {
 356                                 if (get_oid_hex(arg, &oid))
 357                                         die(_("invalid shallow line: %s"), reader.line);
 358                                 register_shallow(the_repository, &oid);
 359                                 continue;
 360                         }
 361                         if (skip_prefix(reader.line, "unshallow ", &arg)) {
 362                                 if (get_oid_hex(arg, &oid))
 363                                         die(_("invalid unshallow line: %s"), reader.line);
 364                                 if (!lookup_object(the_repository, &oid))
 365                                         die(_("object not found: %s"), reader.line);
 366                                 /* make sure that it is parsed as shallow */
 367                                 if (!parse_object(the_repository, &oid))
 368                                         die(_("error in object: %s"), reader.line);
 369                                 if (unregister_shallow(&oid))
 370                                         die(_("no shallow found: %s"), reader.line);
 371                                 continue;
 372                         }
 373                         die(_("expected shallow/unshallow, got %s"), reader.line);
 374                 }
 375         } else if (!args->stateless_rpc)
 376                 send_request(args, fd[1], &req_buf);
 377
 378         if (!args->stateless_rpc) {
 379                 /* If we aren't using the stateless-rpc interface
 380                  * we don't need to retain the headers.
 381                  */
 382                 strbuf_setlen(&req_buf, 0);
 383                 state_len = 0;
 384         }
 385
 386         trace2_region_enter("fetch-pack", "negotiation_v0_v1", the_repository);
 387         flushes = 0;
 388         retval = -1;
 389         if (args->no_dependents)
 390                 goto done;
 391         while ((oid = negotiator->next(negotiator))) {
 392                 packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid));
 393                 print_verbose(args, "have %s", oid_to_hex(oid));
 394                 in_vain++;
 395                 if (flush_at <= ++count) {
 396                         int ack;
 397
 398                         packet_buf_flush(&req_buf);
 399                         send_request(args, fd[1], &req_buf);
 400                         strbuf_setlen(&req_buf, state_len);
 401                         flushes++;
 402                         flush_at = next_flush(args->stateless_rpc, count);
 403
 404                         /*
 405                          * We keep one window "ahead" of the other side, and
 406                          * will wait for an ACK only on the next one
 407                          */
 408                         if (!args->stateless_rpc && count == INITIAL_FLUSH)
 409                                 continue;
 410
 411                         consume_shallow_list(args, &reader);
 412                         do {
 413                                 ack = get_ack(&reader, result_oid);
 414                                 if (ack)
 415                                         print_verbose(args, _("got %s %d %s"), "ack",
 416                                                       ack, oid_to_hex(result_oid));
 417                                 switch (ack) {
 418                                 case ACK:
 419                                         flushes = 0;
 420                                         multi_ack = 0;
 421                                         retval = 0;
 422                                         goto done;
 423                                 case ACK_common:
 424                                 case ACK_ready:
 425                                 case ACK_continue: {
 426                                         struct commit *commit =
 427                                                 lookup_commit(the_repository,
 428                                                               result_oid);
 429                                         int was_common;
 430
 431                                         if (!commit)
 432                                                 die(_("invalid commit %s"), oid_to_hex(result_oid));
 433                                         was_common = negotiator->ack(negotiator, commit);
 434                                         if (args->stateless_rpc
 435                                          && ack == ACK_common
 436                                          && !was_common) {
 437                                                 /* We need to replay the have for this object
 438                                                  * on the next RPC request so the peer knows
 439                                                  * it is in common with us.
 440                                                  */
 441                                                 const char *hex = oid_to_hex(result_oid);
 442                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 443                                                 state_len = req_buf.len;
 444                                                 /*
 445                                                  * Reset in_vain because an ack
 446                                                  * for this commit has not been
 447                                                  * seen.
 448                                                  */
 449                                                 in_vain = 0;
 450                                         } else if (!args->stateless_rpc
 451                                                    || ack != ACK_common)
 452                                                 in_vain = 0;
 453                                         retval = 0;
 454                                         got_continue = 1;
 455                                         if (ack == ACK_ready)
 456                                                 got_ready = 1;
 457                                         break;
 458                                         }
 459                                 }
 460                         } while (ack);
 461                         flushes--;
 462                         if (got_continue && MAX_IN_VAIN < in_vain) {
 463                                 print_verbose(args, _("giving up"));
 464                                 break; /* give up */
 465                         }
 466                         if (got_ready)
 467                                 break;
 468                 }
 469         }
 470 done:
 471         trace2_region_leave("fetch-pack", "negotiation_v0_v1", the_repository);
 472         if (!got_ready || !no_done) {
 473                 packet_buf_write(&req_buf, "done\n");
 474                 send_request(args, fd[1], &req_buf);
 475         }
 476         print_verbose(args, _("done"));
 477         if (retval != 0) {
 478                 multi_ack = 0;
 479                 flushes++;
 480         }
 481         strbuf_release(&req_buf);
 482
 483         if (!got_ready || !no_done)
 484                 consume_shallow_list(args, &reader);
 485         while (flushes || multi_ack) {
 486                 int ack = get_ack(&reader, result_oid);
 487                 if (ack) {
 488                         print_verbose(args, _("got %s (%d) %s"), "ack",
 489                                       ack, oid_to_hex(result_oid));
 490                         if (ack == ACK)
 491                                 return 0;
 492                         multi_ack = 1;
 493                         continue;
 494                 }
 495                 flushes--;
 496         }
 497         /* it is no error to fetch into a completely empty repo */
 498         return count ? retval : 0;
 499 }
 500
 501 static struct commit_list *complete;
 502
 503 static int mark_complete(const struct object_id *oid)
 504 {
 505         struct object *o = parse_object(the_repository, oid);
 506
 507         while (o && o->type == OBJ_TAG) {
 508                 struct tag *t = (struct tag *) o;
 509                 if (!t->tagged)
 510                         break; /* broken repository */
 511                 o->flags |= COMPLETE;
 512                 o = parse_object(the_repository, &t->tagged->oid);
 513         }
 514         if (o && o->type == OBJ_COMMIT) {
 515                 struct commit *commit = (struct commit *)o;
 516                 if (!(commit->object.flags & COMPLETE)) {
 517                         commit->object.flags |= COMPLETE;
 518                         commit_list_insert(commit, &complete);
 519                 }
 520         }
 521         return 0;
 522 }
 523
 524 static int mark_complete_oid(const char *refname, const struct object_id *oid,
 525                              int flag, void *cb_data)
 526 {
 527         return mark_complete(oid);
 528 }
 529
 530 static void mark_recent_complete_commits(struct fetch_pack_args *args,
 531                                          timestamp_t cutoff)
 532 {
 533         while (complete && cutoff <= complete->item->date) {
 534                 print_verbose(args, _("Marking %s as complete"),
 535                               oid_to_hex(&complete->item->object.oid));
 536                 pop_most_recent_commit(&complete, COMPLETE);
 537         }
 538 }
 539
 540 static void add_refs_to_oidset(struct oidset *oids, struct ref *refs)
 541 {
 542         for (; refs; refs = refs->next)
 543                 oidset_insert(oids, &refs->old_oid);
 544 }
 545
 546 static int is_unmatched_ref(const struct ref *ref)
 547 {
 548         struct object_id oid;
 549         const char *p;
 550         return  ref->match_status == REF_NOT_MATCHED &&
 551                 !parse_oid_hex(ref->name, &oid, &p) &&
 552                 *p == '\0' &&
 553                 oideq(&oid, &ref->old_oid);
 554 }
 555
 556 static void filter_refs(struct fetch_pack_args *args,
 557                         struct ref **refs,
 558                         struct ref **sought, int nr_sought)
 559 {
 560         struct ref *newlist = NULL;
 561         struct ref **newtail = &newlist;
 562         struct ref *unmatched = NULL;
 563         struct ref *ref, *next;
 564         struct oidset tip_oids = OIDSET_INIT;
 565         int i;
 566         int strict = !(allow_unadvertised_object_request &
 567                        (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1));
 568
 569         i = 0;
 570         for (ref = *refs; ref; ref = next) {
 571                 int keep = 0;
 572                 next = ref->next;
 573
 574                 if (starts_with(ref->name, "refs/") &&
 575                     check_refname_format(ref->name, 0)) {
 576                         /*
 577                          * trash or a peeled value; do not even add it to
 578                          * unmatched list
 579                          */
 580                         free_one_ref(ref);
 581                         continue;
 582                 } else {
 583                         while (i < nr_sought) {
 584                                 int cmp = strcmp(ref->name, sought[i]->name);
 585                                 if (cmp < 0)
 586                                         break; /* definitely do not have it */
 587                                 else if (cmp == 0) {
 588                                         keep = 1; /* definitely have it */
 589                                         sought[i]->match_status = REF_MATCHED;
 590                                 }
 591                                 i++;
 592                         }
 593
 594                         if (!keep && args->fetch_all &&
 595                             (!args->deepen || !starts_with(ref->name, "refs/tags/")))
 596                                 keep = 1;
 597                 }
 598
 599                 if (keep) {
 600                         *newtail = ref;
 601                         ref->next = NULL;
 602                         newtail = &ref->next;
 603                 } else {
 604                         ref->next = unmatched;
 605                         unmatched = ref;
 606                 }
 607         }
 608
 609         if (strict) {
 610                 for (i = 0; i < nr_sought; i++) {
 611                         ref = sought[i];
 612                         if (!is_unmatched_ref(ref))
 613                                 continue;
 614
 615                         add_refs_to_oidset(&tip_oids, unmatched);
 616                         add_refs_to_oidset(&tip_oids, newlist);
 617                         break;
 618                 }
 619         }
 620
 621         /* Append unmatched requests to the list */
 622         for (i = 0; i < nr_sought; i++) {
 623                 ref = sought[i];
 624                 if (!is_unmatched_ref(ref))
 625                         continue;
 626
 627                 if (!strict || oidset_contains(&tip_oids, &ref->old_oid)) {
 628                         ref->match_status = REF_MATCHED;
 629                         *newtail = copy_ref(ref);
 630                         newtail = &(*newtail)->next;
 631                 } else {
 632                         ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
 633                 }
 634         }
 635
 636         oidset_clear(&tip_oids);
 637         free_refs(unmatched);
 638
 639         *refs = newlist;
 640 }
 641
 642 static void mark_alternate_complete(struct fetch_negotiator *unused,
 643                                     struct object *obj)
 644 {
 645         mark_complete(&obj->oid);
 646 }
 647
 648 struct loose_object_iter {
 649         struct oidset *loose_object_set;
 650         struct ref *refs;
 651 };
 652
 653 /*
 654  * Mark recent commits available locally and reachable from a local ref as
 655  * COMPLETE. If args->no_dependents is false, also mark COMPLETE remote refs as
 656  * COMMON_REF (otherwise, we are not planning to participate in negotiation, and
 657  * thus do not need COMMON_REF marks).
 658  *
 659  * The cutoff time for recency is determined by this heuristic: it is the
 660  * earliest commit time of the objects in refs that are commits and that we know
 661  * the commit time of.
 662  */
 663 static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
 664                                          struct fetch_pack_args *args,
 665                                          struct ref **refs)
 666 {
 667         struct ref *ref;
 668         int old_save_commit_buffer = save_commit_buffer;
 669         timestamp_t cutoff = 0;
 670
 671         save_commit_buffer = 0;
 672
 673         trace2_region_enter("fetch-pack", "parse_remote_refs_and_find_cutoff", NULL);
 674         for (ref = *refs; ref; ref = ref->next) {
 675                 struct object *o;
 676
 677                 if (!has_object_file_with_flags(&ref->old_oid,
 678                                                 OBJECT_INFO_QUICK |
 679                                                         OBJECT_INFO_SKIP_FETCH_OBJECT))
 680                         continue;
 681                 o = parse_object(the_repository, &ref->old_oid);
 682                 if (!o)
 683                         continue;
 684
 685                 /*
 686                  * We already have it -- which may mean that we were
 687                  * in sync with the other side at some time after
 688                  * that (it is OK if we guess wrong here).
 689                  */
 690                 if (o->type == OBJ_COMMIT) {
 691                         struct commit *commit = (struct commit *)o;
 692                         if (!cutoff || cutoff < commit->date)
 693                                 cutoff = commit->date;
 694                 }
 695         }
 696         trace2_region_leave("fetch-pack", "parse_remote_refs_and_find_cutoff", NULL);
 697
 698         /*
 699          * This block marks all local refs as COMPLETE, and then recursively marks all
 700          * parents of those refs as COMPLETE.
 701          */
 702         trace2_region_enter("fetch-pack", "mark_complete_local_refs", NULL);
 703         if (!args->deepen) {
 704                 for_each_ref(mark_complete_oid, NULL);
 705                 for_each_cached_alternate(NULL, mark_alternate_complete);
 706                 commit_list_sort_by_date(&complete);
 707                 if (cutoff)
 708                         mark_recent_complete_commits(args, cutoff);
 709         }
 710         trace2_region_leave("fetch-pack", "mark_complete_local_refs", NULL);
 711
 712         /*
 713          * Mark all complete remote refs as common refs.
 714          * Don't mark them common yet; the server has to be told so first.
 715          */
 716         trace2_region_enter("fetch-pack", "mark_common_remote_refs", NULL);
 717         for (ref = *refs; ref; ref = ref->next) {
 718                 struct object *o = deref_tag(the_repository,
 719                                              lookup_object(the_repository,
 720                                              &ref->old_oid),
 721                                              NULL, 0);
 722
 723                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 724                         continue;
 725
 726                 negotiator->known_common(negotiator,
 727                                          (struct commit *)o);
 728         }
 729         trace2_region_leave("fetch-pack", "mark_common_remote_refs", NULL);
 730
 731         save_commit_buffer = old_save_commit_buffer;
 732 }
 733
 734 /*
 735  * Returns 1 if every object pointed to by the given remote refs is available
 736  * locally and reachable from a local ref, and 0 otherwise.
 737  */
 738 static int everything_local(struct fetch_pack_args *args,
 739                             struct ref **refs)
 740 {
 741         struct ref *ref;
 742         int retval;
 743
 744         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 745                 const struct object_id *remote = &ref->old_oid;
 746                 struct object *o;
 747
 748                 o = lookup_object(the_repository, remote);
 749                 if (!o || !(o->flags & COMPLETE)) {
 750                         retval = 0;
 751                         print_verbose(args, "want %s (%s)", oid_to_hex(remote),
 752                                       ref->name);
 753                         continue;
 754                 }
 755                 print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
 756                               ref->name);
 757         }
 758
 759         return retval;
 760 }
 761
 762 static int sideband_demux(int in, int out, void *data)
 763 {
 764         int *xd = data;
 765         int ret;
 766
 767         ret = recv_sideband("fetch-pack", xd[0], out);
 768         close(out);
 769         return ret;
 770 }
 771
 772 static void write_promisor_file(const char *keep_name,
 773                                 struct ref **sought, int nr_sought)
 774 {
 775         struct strbuf promisor_name = STRBUF_INIT;
 776         int suffix_stripped;
 777         FILE *output;
 778         int i;
 779
 780         strbuf_addstr(&promisor_name, keep_name);
 781         suffix_stripped = strbuf_strip_suffix(&promisor_name, ".keep");
 782         if (!suffix_stripped)
 783                 BUG("name of pack lockfile should end with .keep (was '%s')",
 784                     keep_name);
 785         strbuf_addstr(&promisor_name, ".promisor");
 786
 787         output = xfopen(promisor_name.buf, "w");
 788         for (i = 0; i < nr_sought; i++)
 789                 fprintf(output, "%s %s\n", oid_to_hex(&sought[i]->old_oid),
 790                         sought[i]->name);
 791         fclose(output);
 792
 793         strbuf_release(&promisor_name);
 794 }
 795
 796 static int get_pack(struct fetch_pack_args *args,
 797                     int xd[2], char **pack_lockfile,
 798                     struct ref **sought, int nr_sought)
 799 {
 800         struct async demux;
 801         int do_keep = args->keep_pack;
 802         const char *cmd_name;
 803         struct pack_header header;
 804         int pass_header = 0;
 805         struct child_process cmd = CHILD_PROCESS_INIT;
 806         int ret;
 807
 808         memset(&demux, 0, sizeof(demux));
 809         if (use_sideband) {
 810                 /* xd[] is talking with upload-pack; subprocess reads from
 811                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 812                  * through demux->out.
 813                  */
 814                 demux.proc = sideband_demux;
 815                 demux.data = xd;
 816                 demux.out = -1;
 817                 demux.isolate_sigpipe = 1;
 818                 if (start_async(&demux))
 819                         die(_("fetch-pack: unable to fork off sideband demultiplexer"));
 820         }
 821         else
 822                 demux.out = xd[0];
 823
 824         if (!args->keep_pack && unpack_limit) {
 825
 826                 if (read_pack_header(demux.out, &header))
 827                         die(_("protocol error: bad pack header"));
 828                 pass_header = 1;
 829                 if (ntohl(header.hdr_entries) < unpack_limit)
 830                         do_keep = 0;
 831                 else
 832                         do_keep = 1;
 833         }
 834
 835         if (alternate_shallow_file) {
 836                 argv_array_push(&cmd.args, "--shallow-file");
 837                 argv_array_push(&cmd.args, alternate_shallow_file);
 838         }
 839
 840         if (do_keep || args->from_promisor) {
 841                 if (pack_lockfile)
 842                         cmd.out = -1;
 843                 cmd_name = "index-pack";
 844                 argv_array_push(&cmd.args, cmd_name);
 845                 argv_array_push(&cmd.args, "--stdin");
 846                 if (!args->quiet && !args->no_progress)
 847                         argv_array_push(&cmd.args, "-v");
 848                 if (args->use_thin_pack)
 849                         argv_array_push(&cmd.args, "--fix-thin");
 850                 if (do_keep && (args->lock_pack || unpack_limit)) {
 851                         char hostname[HOST_NAME_MAX + 1];
 852                         if (xgethostname(hostname, sizeof(hostname)))
 853                                 xsnprintf(hostname, sizeof(hostname), "localhost");
 854                         argv_array_pushf(&cmd.args,
 855                                         "--keep=fetch-pack %"PRIuMAX " on %s",
 856                                         (uintmax_t)getpid(), hostname);
 857                 }
 858                 if (args->check_self_contained_and_connected)
 859                         argv_array_push(&cmd.args, "--check-self-contained-and-connected");
 860                 /*
 861                  * If we're obtaining the filename of a lockfile, we'll use
 862                  * that filename to write a .promisor file with more
 863                  * information below. If not, we need index-pack to do it for
 864                  * us.
 865                  */
 866                 if (!(do_keep && pack_lockfile) && args->from_promisor)
 867                         argv_array_push(&cmd.args, "--promisor");
 868         }
 869         else {
 870                 cmd_name = "unpack-objects";
 871                 argv_array_push(&cmd.args, cmd_name);
 872                 if (args->quiet || args->no_progress)
 873                         argv_array_push(&cmd.args, "-q");
 874                 args->check_self_contained_and_connected = 0;
 875         }
 876
 877         if (pass_header)
 878                 argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
 879                                  ntohl(header.hdr_version),
 880                                  ntohl(header.hdr_entries));
 881         if (fetch_fsck_objects >= 0
 882             ? fetch_fsck_objects
 883             : transfer_fsck_objects >= 0
 884             ? transfer_fsck_objects
 885             : 0) {
 886                 if (args->from_promisor)
 887                         /*
 888                          * We cannot use --strict in index-pack because it
 889                          * checks both broken objects and links, but we only
 890                          * want to check for broken objects.
 891                          */
 892                         argv_array_push(&cmd.args, "--fsck-objects");
 893                 else
 894                         argv_array_pushf(&cmd.args, "--strict%s",
 895                                          fsck_msg_types.buf);
 896         }
 897
 898         cmd.in = demux.out;
 899         cmd.git_cmd = 1;
 900         if (start_command(&cmd))
 901                 die(_("fetch-pack: unable to fork off %s"), cmd_name);
 902         if (do_keep && pack_lockfile) {
 903                 *pack_lockfile = index_pack_lockfile(cmd.out);
 904                 close(cmd.out);
 905         }
 906
 907         if (!use_sideband)
 908                 /* Closed by start_command() */
 909                 xd[0] = -1;
 910
 911         ret = finish_command(&cmd);
 912         if (!ret || (args->check_self_contained_and_connected && ret == 1))
 913                 args->self_contained_and_connected =
 914                         args->check_self_contained_and_connected &&
 915                         ret == 0;
 916         else
 917                 die(_("%s failed"), cmd_name);
 918         if (use_sideband && finish_async(&demux))
 919                 die(_("error in sideband demultiplexer"));
 920
 921         /*
 922          * Now that index-pack has succeeded, write the promisor file using the
 923          * obtained .keep filename if necessary
 924          */
 925         if (do_keep && pack_lockfile && args->from_promisor)
 926                 write_promisor_file(*pack_lockfile, sought, nr_sought);
 927
 928         return 0;
 929 }
 930
 931 static int cmp_ref_by_name(const void *a_, const void *b_)
 932 {
 933         const struct ref *a = *((const struct ref **)a_);
 934         const struct ref *b = *((const struct ref **)b_);
 935         return strcmp(a->name, b->name);
 936 }
 937
 938 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 939                                  int fd[2],
 940                                  const struct ref *orig_ref,
 941                                  struct ref **sought, int nr_sought,
 942                                  struct shallow_info *si,
 943                                  char **pack_lockfile)
 944 {
 945         struct repository *r = the_repository;
 946         struct ref *ref = copy_ref_list(orig_ref);
 947         struct object_id oid;
 948         const char *agent_feature;
 949         int agent_len;
 950         struct fetch_negotiator negotiator_alloc;
 951         struct fetch_negotiator *negotiator;
 952
 953         if (args->no_dependents) {
 954                 negotiator = NULL;
 955         } else {
 956                 negotiator = &negotiator_alloc;
 957                 fetch_negotiator_init(r, negotiator);
 958         }
 959
 960         sort_ref_list(&ref, ref_compare_name);
 961         QSORT(sought, nr_sought, cmp_ref_by_name);
 962
 963         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 964                 agent_supported = 1;
 965                 if (agent_len)
 966                         print_verbose(args, _("Server version is %.*s"),
 967                                       agent_len, agent_feature);
 968         }
 969
 970         if (server_supports("shallow"))
 971                 print_verbose(args, _("Server supports %s"), "shallow");
 972         else if (args->depth > 0 || is_repository_shallow(r))
 973                 die(_("Server does not support shallow clients"));
 974         if (args->depth > 0 || args->deepen_since || args->deepen_not)
 975                 args->deepen = 1;
 976         if (server_supports("multi_ack_detailed")) {
 977                 print_verbose(args, _("Server supports %s"), "multi_ack_detailed");
 978                 multi_ack = 2;
 979                 if (server_supports("no-done")) {
 980                         print_verbose(args, _("Server supports %s"), "no-done");
 981                         if (args->stateless_rpc)
 982                                 no_done = 1;
 983                 }
 984         }
 985         else if (server_supports("multi_ack")) {
 986                 print_verbose(args, _("Server supports %s"), "multi_ack");
 987                 multi_ack = 1;
 988         }
 989         if (server_supports("side-band-64k")) {
 990                 print_verbose(args, _("Server supports %s"), "side-band-64k");
 991                 use_sideband = 2;
 992         }
 993         else if (server_supports("side-band")) {
 994                 print_verbose(args, _("Server supports %s"), "side-band");
 995                 use_sideband = 1;
 996         }
 997         if (server_supports("allow-tip-sha1-in-want")) {
 998                 print_verbose(args, _("Server supports %s"), "allow-tip-sha1-in-want");
 999                 allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
1000         }
1001         if (server_supports("allow-reachable-sha1-in-want")) {
1002                 print_verbose(args, _("Server supports %s"), "allow-reachable-sha1-in-want");
1003                 allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
1004         }
1005         if (server_supports("thin-pack"))
1006                 print_verbose(args, _("Server supports %s"), "thin-pack");
1007         else
1008                 args->use_thin_pack = 0;
1009         if (server_supports("no-progress"))
1010                 print_verbose(args, _("Server supports %s"), "no-progress");
1011         else
1012                 args->no_progress = 0;
1013         if (server_supports("include-tag"))
1014                 print_verbose(args, _("Server supports %s"), "include-tag");
1015         else
1016                 args->include_tag = 0;
1017         if (server_supports("ofs-delta"))
1018                 print_verbose(args, _("Server supports %s"), "ofs-delta");
1019         else
1020                 prefer_ofs_delta = 0;
1021
1022         if (server_supports("filter")) {
1023                 server_supports_filtering = 1;
1024                 print_verbose(args, _("Server supports %s"), "filter");
1025         } else if (args->filter_options.choice) {
1026                 warning("filtering not recognized by server, ignoring");
1027         }
1028
1029         if (server_supports("deepen-since")) {
1030                 print_verbose(args, _("Server supports %s"), "deepen-since");
1031                 deepen_since_ok = 1;
1032         } else if (args->deepen_since)
1033                 die(_("Server does not support --shallow-since"));
1034         if (server_supports("deepen-not")) {
1035                 print_verbose(args, _("Server supports %s"), "deepen-not");
1036                 deepen_not_ok = 1;
1037         } else if (args->deepen_not)
1038                 die(_("Server does not support --shallow-exclude"));
1039         if (server_supports("deepen-relative"))
1040                 print_verbose(args, _("Server supports %s"), "deepen-relative");
1041         else if (args->deepen_relative)
1042                 die(_("Server does not support --deepen"));
1043
1044         if (!args->no_dependents) {
1045                 mark_complete_and_common_ref(negotiator, args, &ref);
1046                 filter_refs(args, &ref, sought, nr_sought);
1047                 if (everything_local(args, &ref)) {
1048                         packet_flush(fd[1]);
1049                         goto all_done;
1050                 }
1051         } else {
1052                 filter_refs(args, &ref, sought, nr_sought);
1053         }
1054         if (find_common(negotiator, args, fd, &oid, ref) < 0)
1055                 if (!args->keep_pack)
1056                         /* When cloning, it is not unusual to have
1057                          * no common commit.
1058                          */
1059                         warning(_("no common commits"));
1060
1061         if (args->stateless_rpc)
1062                 packet_flush(fd[1]);
1063         if (args->deepen)
1064                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
1065                                         NULL);
1066         else if (si->nr_ours || si->nr_theirs)
1067                 alternate_shallow_file = setup_temporary_shallow(si->shallow);
1068         else
1069                 alternate_shallow_file = NULL;
1070         if (get_pack(args, fd, pack_lockfile, sought, nr_sought))
1071                 die(_("git fetch-pack: fetch failed."));
1072
1073  all_done:
1074         if (negotiator)
1075                 negotiator->release(negotiator);
1076         return ref;
1077 }
1078
1079 static void add_shallow_requests(struct strbuf *req_buf,
1080                                  const struct fetch_pack_args *args)
1081 {
1082         if (is_repository_shallow(the_repository))
1083                 write_shallow_commits(req_buf, 1, NULL);
1084         if (args->depth > 0)
1085                 packet_buf_write(req_buf, "deepen %d", args->depth);
1086         if (args->deepen_since) {
1087                 timestamp_t max_age = approxidate(args->deepen_since);
1088                 packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
1089         }
1090         if (args->deepen_not) {
1091                 int i;
1092                 for (i = 0; i < args->deepen_not->nr; i++) {
1093                         struct string_list_item *s = args->deepen_not->items + i;
1094                         packet_buf_write(req_buf, "deepen-not %s", s->string);
1095                 }
1096         }
1097         if (args->deepen_relative)
1098                 packet_buf_write(req_buf, "deepen-relative\n");
1099 }
1100
1101 static void add_wants(int no_dependents, const struct ref *wants, struct strbuf *req_buf)
1102 {
1103         int use_ref_in_want = server_supports_feature("fetch", "ref-in-want", 0);
1104
1105         for ( ; wants ; wants = wants->next) {
1106                 const struct object_id *remote = &wants->old_oid;
1107                 struct object *o;
1108
1109                 /*
1110                  * If that object is complete (i.e. it is an ancestor of a
1111                  * local ref), we tell them we have it but do not have to
1112                  * tell them about its ancestors, which they already know
1113                  * about.
1114                  *
1115                  * We use lookup_object here because we are only
1116                  * interested in the case we *know* the object is
1117                  * reachable and we have already scanned it.
1118                  *
1119                  * Do this only if args->no_dependents is false (if it is true,
1120                  * we cannot trust the object flags).
1121                  */
1122                 if (!no_dependents &&
1123                     ((o = lookup_object(the_repository, remote)) != NULL) &&
1124                     (o->flags & COMPLETE)) {
1125                         continue;
1126                 }
1127
1128                 if (!use_ref_in_want || wants->exact_oid)
1129                         packet_buf_write(req_buf, "want %s\n", oid_to_hex(remote));
1130                 else
1131                         packet_buf_write(req_buf, "want-ref %s\n", wants->name);
1132         }
1133 }
1134
1135 static void add_common(struct strbuf *req_buf, struct oidset *common)
1136 {
1137         struct oidset_iter iter;
1138         const struct object_id *oid;
1139         oidset_iter_init(common, &iter);
1140
1141         while ((oid = oidset_iter_next(&iter))) {
1142                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1143         }
1144 }
1145
1146 static int add_haves(struct fetch_negotiator *negotiator,
1147                      int seen_ack,
1148                      struct strbuf *req_buf,
1149                      int *haves_to_send, int *in_vain)
1150 {
1151         int ret = 0;
1152         int haves_added = 0;
1153         const struct object_id *oid;
1154
1155         while ((oid = negotiator->next(negotiator))) {
1156                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1157                 if (++haves_added >= *haves_to_send)
1158                         break;
1159         }
1160
1161         *in_vain += haves_added;
1162         if (!haves_added || (seen_ack && *in_vain >= MAX_IN_VAIN)) {
1163                 /* Send Done */
1164                 packet_buf_write(req_buf, "done\n");
1165                 ret = 1;
1166         }
1167
1168         /* Increase haves to send on next round */
1169         *haves_to_send = next_flush(1, *haves_to_send);
1170
1171         return ret;
1172 }
1173
1174 static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
1175                               struct fetch_pack_args *args,
1176                               const struct ref *wants, struct oidset *common,
1177                               int *haves_to_send, int *in_vain,
1178                               int sideband_all, int seen_ack)
1179 {
1180         int ret = 0;
1181         struct strbuf req_buf = STRBUF_INIT;
1182
1183         if (server_supports_v2("fetch", 1))
1184                 packet_buf_write(&req_buf, "command=fetch");
1185         if (server_supports_v2("agent", 0))
1186                 packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
1187         if (args->server_options && args->server_options->nr &&
1188             server_supports_v2("server-option", 1)) {
1189                 int i;
1190                 for (i = 0; i < args->server_options->nr; i++)
1191                         packet_buf_write(&req_buf, "server-option=%s",
1192                                          args->server_options->items[i].string);
1193         }
1194
1195         packet_buf_delim(&req_buf);
1196         if (args->use_thin_pack)
1197                 packet_buf_write(&req_buf, "thin-pack");
1198         if (args->no_progress)
1199                 packet_buf_write(&req_buf, "no-progress");
1200         if (args->include_tag)
1201                 packet_buf_write(&req_buf, "include-tag");
1202         if (prefer_ofs_delta)
1203                 packet_buf_write(&req_buf, "ofs-delta");
1204         if (sideband_all)
1205                 packet_buf_write(&req_buf, "sideband-all");
1206
1207         /* Add shallow-info and deepen request */
1208         if (server_supports_feature("fetch", "shallow", 0))
1209                 add_shallow_requests(&req_buf, args);
1210         else if (is_repository_shallow(the_repository) || args->deepen)
1211                 die(_("Server does not support shallow requests"));
1212
1213         /* Add filter */
1214         if (server_supports_feature("fetch", "filter", 0) &&
1215             args->filter_options.choice) {
1216                 const char *spec =
1217                         expand_list_objects_filter_spec(&args->filter_options);
1218                 print_verbose(args, _("Server supports filter"));
1219                 packet_buf_write(&req_buf, "filter %s", spec);
1220         } else if (args->filter_options.choice) {
1221                 warning("filtering not recognized by server, ignoring");
1222         }
1223
1224         /* add wants */
1225         add_wants(args->no_dependents, wants, &req_buf);
1226
1227         if (args->no_dependents) {
1228                 packet_buf_write(&req_buf, "done");
1229                 ret = 1;
1230         } else {
1231                 /* Add all of the common commits we've found in previous rounds */
1232                 add_common(&req_buf, common);
1233
1234                 /* Add initial haves */
1235                 ret = add_haves(negotiator, seen_ack, &req_buf,
1236                                 haves_to_send, in_vain);
1237         }
1238
1239         /* Send request */
1240         packet_buf_flush(&req_buf);
1241         if (write_in_full(fd_out, req_buf.buf, req_buf.len) < 0)
1242                 die_errno(_("unable to write request to remote"));
1243
1244         strbuf_release(&req_buf);
1245         return ret;
1246 }
1247
1248 /*
1249  * Processes a section header in a server's response and checks if it matches
1250  * `section`.  If the value of `peek` is 1, the header line will be peeked (and
1251  * not consumed); if 0, the line will be consumed and the function will die if
1252  * the section header doesn't match what was expected.
1253  */
1254 static int process_section_header(struct packet_reader *reader,
1255                                   const char *section, int peek)
1256 {
1257         int ret;
1258
1259         if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
1260                 die(_("error reading section header '%s'"), section);
1261
1262         ret = !strcmp(reader->line, section);
1263
1264         if (!peek) {
1265                 if (!ret)
1266                         die(_("expected '%s', received '%s'"),
1267                             section, reader->line);
1268                 packet_reader_read(reader);
1269         }
1270
1271         return ret;
1272 }
1273
1274 enum common_found {
1275         /*
1276          * No commit was found to be possessed by both the client and the
1277          * server, and "ready" was not received.
1278          */
1279         NO_COMMON_FOUND,
1280
1281         /*
1282          * At least one commit was found to be possessed by both the client and
1283          * the server, and "ready" was not received.
1284          */
1285         COMMON_FOUND,
1286
1287         /*
1288          * "ready" was received, indicating that the server is ready to send
1289          * the packfile without any further negotiation.
1290          */
1291         READY
1292 };
1293
1294 static enum common_found process_acks(struct fetch_negotiator *negotiator,
1295                                       struct packet_reader *reader,
1296                                       struct oidset *common)
1297 {
1298         /* received */
1299         int received_ready = 0;
1300         int received_ack = 0;
1301
1302         process_section_header(reader, "acknowledgments", 0);
1303         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1304                 const char *arg;
1305
1306                 if (!strcmp(reader->line, "NAK"))
1307                         continue;
1308
1309                 if (skip_prefix(reader->line, "ACK ", &arg)) {
1310                         struct object_id oid;
1311                         received_ack = 1;
1312                         if (!get_oid_hex(arg, &oid)) {
1313                                 struct commit *commit;
1314                                 oidset_insert(common, &oid);
1315                                 commit = lookup_commit(the_repository, &oid);
1316                                 if (negotiator)
1317                                         negotiator->ack(negotiator, commit);
1318                         }
1319                         continue;
1320                 }
1321
1322                 if (!strcmp(reader->line, "ready")) {
1323                         received_ready = 1;
1324                         continue;
1325                 }
1326
1327                 die(_("unexpected acknowledgment line: '%s'"), reader->line);
1328         }
1329
1330         if (reader->status != PACKET_READ_FLUSH &&
1331             reader->status != PACKET_READ_DELIM)
1332                 die(_("error processing acks: %d"), reader->status);
1333
1334         /*
1335          * If an "acknowledgments" section is sent, a packfile is sent if and
1336          * only if "ready" was sent in this section. The other sections
1337          * ("shallow-info" and "wanted-refs") are sent only if a packfile is
1338          * sent. Therefore, a DELIM is expected if "ready" is sent, and a FLUSH
1339          * otherwise.
1340          */
1341         if (received_ready && reader->status != PACKET_READ_DELIM)
1342                 die(_("expected packfile to be sent after 'ready'"));
1343         if (!received_ready && reader->status != PACKET_READ_FLUSH)
1344                 die(_("expected no other sections to be sent after no 'ready'"));
1345
1346         return received_ready ? READY :
1347                 (received_ack ? COMMON_FOUND : NO_COMMON_FOUND);
1348 }
1349
1350 static void receive_shallow_info(struct fetch_pack_args *args,
1351                                  struct packet_reader *reader,
1352                                  struct oid_array *shallows,
1353                                  struct shallow_info *si)
1354 {
1355         int unshallow_received = 0;
1356
1357         process_section_header(reader, "shallow-info", 0);
1358         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1359                 const char *arg;
1360                 struct object_id oid;
1361
1362                 if (skip_prefix(reader->line, "shallow ", &arg)) {
1363                         if (get_oid_hex(arg, &oid))
1364                                 die(_("invalid shallow line: %s"), reader->line);
1365                         oid_array_append(shallows, &oid);
1366                         continue;
1367                 }
1368                 if (skip_prefix(reader->line, "unshallow ", &arg)) {
1369                         if (get_oid_hex(arg, &oid))
1370                                 die(_("invalid unshallow line: %s"), reader->line);
1371                         if (!lookup_object(the_repository, &oid))
1372                                 die(_("object not found: %s"), reader->line);
1373                         /* make sure that it is parsed as shallow */
1374                         if (!parse_object(the_repository, &oid))
1375                                 die(_("error in object: %s"), reader->line);
1376                         if (unregister_shallow(&oid))
1377                                 die(_("no shallow found: %s"), reader->line);
1378                         unshallow_received = 1;
1379                         continue;
1380                 }
1381                 die(_("expected shallow/unshallow, got %s"), reader->line);
1382         }
1383
1384         if (reader->status != PACKET_READ_FLUSH &&
1385             reader->status != PACKET_READ_DELIM)
1386                 die(_("error processing shallow info: %d"), reader->status);
1387
1388         if (args->deepen || unshallow_received) {
1389                 /*
1390                  * Treat these as shallow lines caused by our depth settings.
1391                  * In v0, these lines cannot cause refs to be rejected; do the
1392                  * same.
1393                  */
1394                 int i;
1395
1396                 for (i = 0; i < shallows->nr; i++)
1397                         register_shallow(the_repository, &shallows->oid[i]);
1398                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
1399                                         NULL);
1400                 args->deepen = 1;
1401         } else if (shallows->nr) {
1402                 /*
1403                  * Treat these as shallow lines caused by the remote being
1404                  * shallow. In v0, remote refs that reach these objects are
1405                  * rejected (unless --update-shallow is set); do the same.
1406                  */
1407                 prepare_shallow_info(si, shallows);
1408                 if (si->nr_ours || si->nr_theirs)
1409                         alternate_shallow_file =
1410                                 setup_temporary_shallow(si->shallow);
1411                 else
1412                         alternate_shallow_file = NULL;
1413         } else {
1414                 alternate_shallow_file = NULL;
1415         }
1416 }
1417
1418 static int cmp_name_ref(const void *name, const void *ref)
1419 {
1420         return strcmp(name, (*(struct ref **)ref)->name);
1421 }
1422
1423 static void receive_wanted_refs(struct packet_reader *reader,
1424                                 struct ref **sought, int nr_sought)
1425 {
1426         process_section_header(reader, "wanted-refs", 0);
1427         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1428                 struct object_id oid;
1429                 const char *end;
1430                 struct ref **found;
1431
1432                 if (parse_oid_hex(reader->line, &oid, &end) || *end++ != ' ')
1433                         die(_("expected wanted-ref, got '%s'"), reader->line);
1434
1435                 found = bsearch(end, sought, nr_sought, sizeof(*sought),
1436                                 cmp_name_ref);
1437                 if (!found)
1438                         die(_("unexpected wanted-ref: '%s'"), reader->line);
1439                 oidcpy(&(*found)->old_oid, &oid);
1440         }
1441
1442         if (reader->status != PACKET_READ_DELIM)
1443                 die(_("error processing wanted refs: %d"), reader->status);
1444 }
1445
1446 enum fetch_state {
1447         FETCH_CHECK_LOCAL = 0,
1448         FETCH_SEND_REQUEST,
1449         FETCH_PROCESS_ACKS,
1450         FETCH_GET_PACK,
1451         FETCH_DONE,
1452 };
1453
1454 static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
1455                                     int fd[2],
1456                                     const struct ref *orig_ref,
1457                                     struct ref **sought, int nr_sought,
1458                                     struct oid_array *shallows,
1459                                     struct shallow_info *si,
1460                                     char **pack_lockfile)
1461 {
1462         struct repository *r = the_repository;
1463         struct ref *ref = copy_ref_list(orig_ref);
1464         enum fetch_state state = FETCH_CHECK_LOCAL;
1465         struct oidset common = OIDSET_INIT;
1466         struct packet_reader reader;
1467         int in_vain = 0, negotiation_started = 0;
1468         int haves_to_send = INITIAL_FLUSH;
1469         struct fetch_negotiator negotiator_alloc;
1470         struct fetch_negotiator *negotiator;
1471         int seen_ack = 0;
1472
1473         if (args->no_dependents) {
1474                 negotiator = NULL;
1475         } else {
1476                 negotiator = &negotiator_alloc;
1477                 fetch_negotiator_init(r, negotiator);
1478         }
1479
1480         packet_reader_init(&reader, fd[0], NULL, 0,
1481                            PACKET_READ_CHOMP_NEWLINE |
1482                            PACKET_READ_DIE_ON_ERR_PACKET);
1483         if (git_env_bool("GIT_TEST_SIDEBAND_ALL", 1) &&
1484             server_supports_feature("fetch", "sideband-all", 0)) {
1485                 reader.use_sideband = 1;
1486                 reader.me = "fetch-pack";
1487         }
1488
1489         while (state != FETCH_DONE) {
1490                 switch (state) {
1491                 case FETCH_CHECK_LOCAL:
1492                         sort_ref_list(&ref, ref_compare_name);
1493                         QSORT(sought, nr_sought, cmp_ref_by_name);
1494
1495                         /* v2 supports these by default */
1496                         allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
1497                         use_sideband = 2;
1498                         if (args->depth > 0 || args->deepen_since || args->deepen_not)
1499                                 args->deepen = 1;
1500
1501                         /* Filter 'ref' by 'sought' and those that aren't local */
1502                         if (!args->no_dependents) {
1503                                 mark_complete_and_common_ref(negotiator, args, &ref);
1504                                 filter_refs(args, &ref, sought, nr_sought);
1505                                 if (everything_local(args, &ref))
1506                                         state = FETCH_DONE;
1507                                 else
1508                                         state = FETCH_SEND_REQUEST;
1509
1510                                 mark_tips(negotiator, args->negotiation_tips);
1511                                 for_each_cached_alternate(negotiator,
1512                                                           insert_one_alternate_object);
1513                         } else {
1514                                 filter_refs(args, &ref, sought, nr_sought);
1515                                 state = FETCH_SEND_REQUEST;
1516                         }
1517                         break;
1518                 case FETCH_SEND_REQUEST:
1519                         if (!negotiation_started) {
1520                                 negotiation_started = 1;
1521                                 trace2_region_enter("fetch-pack",
1522                                                     "negotiation_v2",
1523                                                     the_repository);
1524                         }
1525                         if (send_fetch_request(negotiator, fd[1], args, ref,
1526                                                &common,
1527                                                &haves_to_send, &in_vain,
1528                                                reader.use_sideband,
1529                                                seen_ack))
1530                                 state = FETCH_GET_PACK;
1531                         else
1532                                 state = FETCH_PROCESS_ACKS;
1533                         break;
1534                 case FETCH_PROCESS_ACKS:
1535                         /* Process ACKs/NAKs */
1536                         switch (process_acks(negotiator, &reader, &common)) {
1537                         case READY:
1538                                 state = FETCH_GET_PACK;
1539                                 break;
1540                         case COMMON_FOUND:
1541                                 in_vain = 0;
1542                                 seen_ack = 1;
1543                                 /* fallthrough */
1544                         case NO_COMMON_FOUND:
1545                                 state = FETCH_SEND_REQUEST;
1546                                 break;
1547                         }
1548                         break;
1549                 case FETCH_GET_PACK:
1550                         trace2_region_leave("fetch-pack",
1551                                             "negotiation_v2",
1552                                             the_repository);
1553                         /* Check for shallow-info section */
1554                         if (process_section_header(&reader, "shallow-info", 1))
1555                                 receive_shallow_info(args, &reader, shallows, si);
1556
1557                         if (process_section_header(&reader, "wanted-refs", 1))
1558                                 receive_wanted_refs(&reader, sought, nr_sought);
1559
1560                         /* get the pack */
1561                         process_section_header(&reader, "packfile", 0);
1562                         if (get_pack(args, fd, pack_lockfile, sought, nr_sought))
1563                                 die(_("git fetch-pack: fetch failed."));
1564
1565                         state = FETCH_DONE;
1566                         break;
1567                 case FETCH_DONE:
1568                         continue;
1569                 }
1570         }
1571
1572         if (negotiator)
1573                 negotiator->release(negotiator);
1574         oidset_clear(&common);
1575         return ref;
1576 }
1577
1578 static int fetch_pack_config_cb(const char *var, const char *value, void *cb)
1579 {
1580         if (strcmp(var, "fetch.fsck.skiplist") == 0) {
1581                 const char *path;
1582
1583                 if (git_config_pathname(&path, var, value))
1584                         return 1;
1585                 strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
1586                         fsck_msg_types.len ? ',' : '=', path);
1587                 free((char *)path);
1588                 return 0;
1589         }
1590
1591         if (skip_prefix(var, "fetch.fsck.", &var)) {
1592                 if (is_valid_msg_type(var, value))
1593                         strbuf_addf(&fsck_msg_types, "%c%s=%s",
1594                                 fsck_msg_types.len ? ',' : '=', var, value);
1595                 else
1596                         warning("Skipping unknown msg id '%s'", var);
1597                 return 0;
1598         }
1599
1600         return git_default_config(var, value, cb);
1601 }
1602
1603 static void fetch_pack_config(void)
1604 {
1605         git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
1606         git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
1607         git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
1608         git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
1609         git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
1610
1611         git_config(fetch_pack_config_cb, NULL);
1612 }
1613
1614 static void fetch_pack_setup(void)
1615 {
1616         static int did_setup;
1617         if (did_setup)
1618                 return;
1619         fetch_pack_config();
1620         if (0 <= transfer_unpack_limit)
1621                 unpack_limit = transfer_unpack_limit;
1622         else if (0 <= fetch_unpack_limit)
1623                 unpack_limit = fetch_unpack_limit;
1624         did_setup = 1;
1625 }
1626
1627 static int remove_duplicates_in_refs(struct ref **ref, int nr)
1628 {
1629         struct string_list names = STRING_LIST_INIT_NODUP;
1630         int src, dst;
1631
1632         for (src = dst = 0; src < nr; src++) {
1633                 struct string_list_item *item;
1634                 item = string_list_insert(&names, ref[src]->name);
1635                 if (item->util)
1636                         continue; /* already have it */
1637                 item->util = ref[src];
1638                 if (src != dst)
1639                         ref[dst] = ref[src];
1640                 dst++;
1641         }
1642         for (src = dst; src < nr; src++)
1643                 ref[src] = NULL;
1644         string_list_clear(&names, 0);
1645         return dst;
1646 }
1647
1648 static void update_shallow(struct fetch_pack_args *args,
1649                            struct ref **sought, int nr_sought,
1650                            struct shallow_info *si)
1651 {
1652         struct oid_array ref = OID_ARRAY_INIT;
1653         int *status;
1654         int i;
1655
1656         if (args->deepen && alternate_shallow_file) {
1657                 if (*alternate_shallow_file == '\0') { /* --unshallow */
1658                         unlink_or_warn(git_path_shallow(the_repository));
1659                         rollback_shallow_file(the_repository, &shallow_lock);
1660                 } else
1661                         commit_shallow_file(the_repository, &shallow_lock);
1662                 alternate_shallow_file = NULL;
1663                 return;
1664         }
1665
1666         if (!si->shallow || !si->shallow->nr)
1667                 return;
1668
1669         if (args->cloning) {
1670                 /*
1671                  * remote is shallow, but this is a clone, there are
1672                  * no objects in repo to worry about. Accept any
1673                  * shallow points that exist in the pack (iow in repo
1674                  * after get_pack() and reprepare_packed_git())
1675                  */
1676                 struct oid_array extra = OID_ARRAY_INIT;
1677                 struct object_id *oid = si->shallow->oid;
1678                 for (i = 0; i < si->shallow->nr; i++)
1679                         if (has_object_file(&oid[i]))
1680                                 oid_array_append(&extra, &oid[i]);
1681                 if (extra.nr) {
1682                         setup_alternate_shallow(&shallow_lock,
1683                                                 &alternate_shallow_file,
1684                                                 &extra);
1685                         commit_shallow_file(the_repository, &shallow_lock);
1686                         alternate_shallow_file = NULL;
1687                 }
1688                 oid_array_clear(&extra);
1689                 return;
1690         }
1691
1692         if (!si->nr_ours && !si->nr_theirs)
1693                 return;
1694
1695         remove_nonexistent_theirs_shallow(si);
1696         if (!si->nr_ours && !si->nr_theirs)
1697                 return;
1698         for (i = 0; i < nr_sought; i++)
1699                 oid_array_append(&ref, &sought[i]->old_oid);
1700         si->ref = &ref;
1701
1702         if (args->update_shallow) {
1703                 /*
1704                  * remote is also shallow, .git/shallow may be updated
1705                  * so all refs can be accepted. Make sure we only add
1706                  * shallow roots that are actually reachable from new
1707                  * refs.
1708                  */
1709                 struct oid_array extra = OID_ARRAY_INIT;
1710                 struct object_id *oid = si->shallow->oid;
1711                 assign_shallow_commits_to_refs(si, NULL, NULL);
1712                 if (!si->nr_ours && !si->nr_theirs) {
1713                         oid_array_clear(&ref);
1714                         return;
1715                 }
1716                 for (i = 0; i < si->nr_ours; i++)
1717                         oid_array_append(&extra, &oid[si->ours[i]]);
1718                 for (i = 0; i < si->nr_theirs; i++)
1719                         oid_array_append(&extra, &oid[si->theirs[i]]);
1720                 setup_alternate_shallow(&shallow_lock,
1721                                         &alternate_shallow_file,
1722                                         &extra);
1723                 commit_shallow_file(the_repository, &shallow_lock);
1724                 oid_array_clear(&extra);
1725                 oid_array_clear(&ref);
1726                 alternate_shallow_file = NULL;
1727                 return;
1728         }
1729
1730         /*
1731          * remote is also shallow, check what ref is safe to update
1732          * without updating .git/shallow
1733          */
1734         status = xcalloc(nr_sought, sizeof(*status));
1735         assign_shallow_commits_to_refs(si, NULL, status);
1736         if (si->nr_ours || si->nr_theirs) {
1737                 for (i = 0; i < nr_sought; i++)
1738                         if (status[i])
1739                                 sought[i]->status = REF_STATUS_REJECT_SHALLOW;
1740         }
1741         free(status);
1742         oid_array_clear(&ref);
1743 }
1744
1745 static int iterate_ref_map(void *cb_data, struct object_id *oid)
1746 {
1747         struct ref **rm = cb_data;
1748         struct ref *ref = *rm;
1749
1750         if (!ref)
1751                 return -1; /* end of the list */
1752         *rm = ref->next;
1753         oidcpy(oid, &ref->old_oid);
1754         return 0;
1755 }
1756
1757 struct ref *fetch_pack(struct fetch_pack_args *args,
1758                        int fd[],
1759                        const struct ref *ref,
1760                        struct ref **sought, int nr_sought,
1761                        struct oid_array *shallow,
1762                        char **pack_lockfile,
1763                        enum protocol_version version)
1764 {
1765         struct ref *ref_cpy;
1766         struct shallow_info si;
1767         struct oid_array shallows_scratch = OID_ARRAY_INIT;
1768
1769         fetch_pack_setup();
1770         if (nr_sought)
1771                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
1772
1773         if (args->no_dependents && !args->filter_options.choice) {
1774                 /*
1775                  * The protocol does not support requesting that only the
1776                  * wanted objects be sent, so approximate this by setting a
1777                  * "blob:none" filter if no filter is already set. This works
1778                  * for all object types: note that wanted blobs will still be
1779                  * sent because they are directly specified as a "want".
1780                  *
1781                  * NEEDSWORK: Add an option in the protocol to request that
1782                  * only the wanted objects be sent, and implement it.
1783                  */
1784                 parse_list_objects_filter(&args->filter_options, "blob:none");
1785         }
1786
1787         if (version != protocol_v2 && !ref) {
1788                 packet_flush(fd[1]);
1789                 die(_("no matching remote head"));
1790         }
1791         if (version == protocol_v2) {
1792                 if (shallow->nr)
1793                         BUG("Protocol V2 does not provide shallows at this point in the fetch");
1794                 memset(&si, 0, sizeof(si));
1795                 ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
1796                                            &shallows_scratch, &si,
1797                                            pack_lockfile);
1798         } else {
1799                 prepare_shallow_info(&si, shallow);
1800                 ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
1801                                         &si, pack_lockfile);
1802         }
1803         reprepare_packed_git(the_repository);
1804
1805         if (!args->cloning && args->deepen) {
1806                 struct check_connected_options opt = CHECK_CONNECTED_INIT;
1807                 struct ref *iterator = ref_cpy;
1808                 opt.shallow_file = alternate_shallow_file;
1809                 if (args->deepen)
1810                         opt.is_deepening_fetch = 1;
1811                 if (check_connected(iterate_ref_map, &iterator, &opt)) {
1812                         error(_("remote did not send all necessary objects"));
1813                         free_refs(ref_cpy);
1814                         ref_cpy = NULL;
1815                         rollback_shallow_file(the_repository, &shallow_lock);
1816                         goto cleanup;
1817                 }
1818                 args->connectivity_checked = 1;
1819         }
1820
1821         update_shallow(args, sought, nr_sought, &si);
1822 cleanup:
1823         clear_shallow_info(&si);
1824         oid_array_clear(&shallows_scratch);
1825         return ref_cpy;
1826 }
1827
1828 int report_unmatched_refs(struct ref **sought, int nr_sought)
1829 {
1830         int i, ret = 0;
1831
1832         for (i = 0; i < nr_sought; i++) {
1833                 if (!sought[i])
1834                         continue;
1835                 switch (sought[i]->match_status) {
1836                 case REF_MATCHED:
1837                         continue;
1838                 case REF_NOT_MATCHED:
1839                         error(_("no such remote ref %s"), sought[i]->name);
1840                         break;
1841                 case REF_UNADVERTISED_NOT_ALLOWED:
1842                         error(_("Server does not allow request for unadvertised object %s"),
1843                               sought[i]->name);
1844                         break;
1845                 }
1846                 ret = 1;
1847         }
1848         return ret;
1849 }