git.oblomov.eu Git - git/blob - fetch-pack.c

   1 #include "cache.h"
   2 #include "repository.h"
   3 #include "config.h"
   4 #include "lockfile.h"
   5 #include "refs.h"
   6 #include "pkt-line.h"
   7 #include "commit.h"
   8 #include "tag.h"
   9 #include "exec-cmd.h"
  10 #include "pack.h"
  11 #include "sideband.h"
  12 #include "fetch-pack.h"
  13 #include "remote.h"
  14 #include "run-command.h"
  15 #include "connect.h"
  16 #include "transport.h"
  17 #include "version.h"
  18 #include "sha1-array.h"
  19 #include "oidset.h"
  20 #include "packfile.h"
  21 #include "object-store.h"
  22 #include "connected.h"
  23 #include "fetch-negotiator.h"
  24 #include "fsck.h"
  25
  26 static int transfer_unpack_limit = -1;
  27 static int fetch_unpack_limit = -1;
  28 static int unpack_limit = 100;
  29 static int prefer_ofs_delta = 1;
  30 static int no_done;
  31 static int deepen_since_ok;
  32 static int deepen_not_ok;
  33 static int fetch_fsck_objects = -1;
  34 static int transfer_fsck_objects = -1;
  35 static int agent_supported;
  36 static int server_supports_filtering;
  37 static struct lock_file shallow_lock;
  38 static const char *alternate_shallow_file;
  39 static char *negotiation_algorithm;
  40 static struct strbuf fsck_msg_types = STRBUF_INIT;
  41
  42 /* Remember to update object flag allocation in object.h */
  43 #define COMPLETE        (1U << 0)
  44 #define ALTERNATE       (1U << 1)
  45
  46 /*
  47  * After sending this many "have"s if we do not get any new ACK , we
  48  * give up traversing our history.
  49  */
  50 #define MAX_IN_VAIN 256
  51
  52 static int multi_ack, use_sideband;
  53 /* Allow specifying sha1 if it is a ref tip. */
  54 #define ALLOW_TIP_SHA1  01
  55 /* Allow request of a sha1 if it is reachable from a ref (possibly hidden ref). */
  56 #define ALLOW_REACHABLE_SHA1    02
  57 static unsigned int allow_unadvertised_object_request;
  58
  59 __attribute__((format (printf, 2, 3)))
  60 static inline void print_verbose(const struct fetch_pack_args *args,
  61                                  const char *fmt, ...)
  62 {
  63         va_list params;
  64
  65         if (!args->verbose)
  66                 return;
  67
  68         va_start(params, fmt);
  69         vfprintf(stderr, fmt, params);
  70         va_end(params);
  71         fputc('\n', stderr);
  72 }
  73
  74 struct alternate_object_cache {
  75         struct object **items;
  76         size_t nr, alloc;
  77 };
  78
  79 static void cache_one_alternate(const struct object_id *oid,
  80                                 void *vcache)
  81 {
  82         struct alternate_object_cache *cache = vcache;
  83         struct object *obj = parse_object(the_repository, oid);
  84
  85         if (!obj || (obj->flags & ALTERNATE))
  86                 return;
  87
  88         obj->flags |= ALTERNATE;
  89         ALLOC_GROW(cache->items, cache->nr + 1, cache->alloc);
  90         cache->items[cache->nr++] = obj;
  91 }
  92
  93 static void for_each_cached_alternate(struct fetch_negotiator *negotiator,
  94                                       void (*cb)(struct fetch_negotiator *,
  95                                                  struct object *))
  96 {
  97         static int initialized;
  98         static struct alternate_object_cache cache;
  99         size_t i;
 100
 101         if (!initialized) {
 102                 for_each_alternate_ref(cache_one_alternate, &cache);
 103                 initialized = 1;
 104         }
 105
 106         for (i = 0; i < cache.nr; i++)
 107                 cb(negotiator, cache.items[i]);
 108 }
 109
 110 static int rev_list_insert_ref(struct fetch_negotiator *negotiator,
 111                                const char *refname,
 112                                const struct object_id *oid)
 113 {
 114         struct object *o = deref_tag(the_repository,
 115                                      parse_object(the_repository, oid),
 116                                      refname, 0);
 117
 118         if (o && o->type == OBJ_COMMIT)
 119                 negotiator->add_tip(negotiator, (struct commit *)o);
 120
 121         return 0;
 122 }
 123
 124 static int rev_list_insert_ref_oid(const char *refname, const struct object_id *oid,
 125                                    int flag, void *cb_data)
 126 {
 127         return rev_list_insert_ref(cb_data, refname, oid);
 128 }
 129
 130 enum ack_type {
 131         NAK = 0,
 132         ACK,
 133         ACK_continue,
 134         ACK_common,
 135         ACK_ready
 136 };
 137
 138 static void consume_shallow_list(struct fetch_pack_args *args,
 139                                  struct packet_reader *reader)
 140 {
 141         if (args->stateless_rpc && args->deepen) {
 142                 /* If we sent a depth we will get back "duplicate"
 143                  * shallow and unshallow commands every time there
 144                  * is a block of have lines exchanged.
 145                  */
 146                 while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
 147                         if (starts_with(reader->line, "shallow "))
 148                                 continue;
 149                         if (starts_with(reader->line, "unshallow "))
 150                                 continue;
 151                         die(_("git fetch-pack: expected shallow list"));
 152                 }
 153                 if (reader->status != PACKET_READ_FLUSH)
 154                         die(_("git fetch-pack: expected a flush packet after shallow list"));
 155         }
 156 }
 157
 158 static enum ack_type get_ack(struct packet_reader *reader,
 159                              struct object_id *result_oid)
 160 {
 161         int len;
 162         const char *arg;
 163
 164         if (packet_reader_read(reader) != PACKET_READ_NORMAL)
 165                 die(_("git fetch-pack: expected ACK/NAK, got a flush packet"));
 166         len = reader->pktlen;
 167
 168         if (!strcmp(reader->line, "NAK"))
 169                 return NAK;
 170         if (skip_prefix(reader->line, "ACK ", &arg)) {
 171                 if (!get_oid_hex(arg, result_oid)) {
 172                         arg += 40;
 173                         len -= arg - reader->line;
 174                         if (len < 1)
 175                                 return ACK;
 176                         if (strstr(arg, "continue"))
 177                                 return ACK_continue;
 178                         if (strstr(arg, "common"))
 179                                 return ACK_common;
 180                         if (strstr(arg, "ready"))
 181                                 return ACK_ready;
 182                         return ACK;
 183                 }
 184         }
 185         die(_("git fetch-pack: expected ACK/NAK, got '%s'"), reader->line);
 186 }
 187
 188 static void send_request(struct fetch_pack_args *args,
 189                          int fd, struct strbuf *buf)
 190 {
 191         if (args->stateless_rpc) {
 192                 send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
 193                 packet_flush(fd);
 194         } else
 195                 write_or_die(fd, buf->buf, buf->len);
 196 }
 197
 198 static void insert_one_alternate_object(struct fetch_negotiator *negotiator,
 199                                         struct object *obj)
 200 {
 201         rev_list_insert_ref(negotiator, NULL, &obj->oid);
 202 }
 203
 204 #define INITIAL_FLUSH 16
 205 #define PIPESAFE_FLUSH 32
 206 #define LARGE_FLUSH 16384
 207
 208 static int next_flush(int stateless_rpc, int count)
 209 {
 210         if (stateless_rpc) {
 211                 if (count < LARGE_FLUSH)
 212                         count <<= 1;
 213                 else
 214                         count = count * 11 / 10;
 215         } else {
 216                 if (count < PIPESAFE_FLUSH)
 217                         count <<= 1;
 218                 else
 219                         count += PIPESAFE_FLUSH;
 220         }
 221         return count;
 222 }
 223
 224 static void mark_tips(struct fetch_negotiator *negotiator,
 225                       const struct oid_array *negotiation_tips)
 226 {
 227         int i;
 228
 229         if (!negotiation_tips) {
 230                 for_each_ref(rev_list_insert_ref_oid, negotiator);
 231                 return;
 232         }
 233
 234         for (i = 0; i < negotiation_tips->nr; i++)
 235                 rev_list_insert_ref(negotiator, NULL,
 236                                     &negotiation_tips->oid[i]);
 237         return;
 238 }
 239
 240 static int find_common(struct fetch_negotiator *negotiator,
 241                        struct fetch_pack_args *args,
 242                        int fd[2], struct object_id *result_oid,
 243                        struct ref *refs)
 244 {
 245         int fetching;
 246         int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
 247         const struct object_id *oid;
 248         unsigned in_vain = 0;
 249         int got_continue = 0;
 250         int got_ready = 0;
 251         struct strbuf req_buf = STRBUF_INIT;
 252         size_t state_len = 0;
 253         struct packet_reader reader;
 254
 255         if (args->stateless_rpc && multi_ack == 1)
 256                 die(_("--stateless-rpc requires multi_ack_detailed"));
 257
 258         packet_reader_init(&reader, fd[0], NULL, 0,
 259                            PACKET_READ_CHOMP_NEWLINE |
 260                            PACKET_READ_DIE_ON_ERR_PACKET);
 261
 262         if (!args->no_dependents) {
 263                 mark_tips(negotiator, args->negotiation_tips);
 264                 for_each_cached_alternate(negotiator, insert_one_alternate_object);
 265         }
 266
 267         fetching = 0;
 268         for ( ; refs ; refs = refs->next) {
 269                 struct object_id *remote = &refs->old_oid;
 270                 const char *remote_hex;
 271                 struct object *o;
 272
 273                 /*
 274                  * If that object is complete (i.e. it is an ancestor of a
 275                  * local ref), we tell them we have it but do not have to
 276                  * tell them about its ancestors, which they already know
 277                  * about.
 278                  *
 279                  * We use lookup_object here because we are only
 280                  * interested in the case we *know* the object is
 281                  * reachable and we have already scanned it.
 282                  *
 283                  * Do this only if args->no_dependents is false (if it is true,
 284                  * we cannot trust the object flags).
 285                  */
 286                 if (!args->no_dependents &&
 287                     ((o = lookup_object(the_repository, remote->hash)) != NULL) &&
 288                                 (o->flags & COMPLETE)) {
 289                         continue;
 290                 }
 291
 292                 remote_hex = oid_to_hex(remote);
 293                 if (!fetching) {
 294                         struct strbuf c = STRBUF_INIT;
 295                         if (multi_ack == 2)     strbuf_addstr(&c, " multi_ack_detailed");
 296                         if (multi_ack == 1)     strbuf_addstr(&c, " multi_ack");
 297                         if (no_done)            strbuf_addstr(&c, " no-done");
 298                         if (use_sideband == 2)  strbuf_addstr(&c, " side-band-64k");
 299                         if (use_sideband == 1)  strbuf_addstr(&c, " side-band");
 300                         if (args->deepen_relative) strbuf_addstr(&c, " deepen-relative");
 301                         if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
 302                         if (args->no_progress)   strbuf_addstr(&c, " no-progress");
 303                         if (args->include_tag)   strbuf_addstr(&c, " include-tag");
 304                         if (prefer_ofs_delta)   strbuf_addstr(&c, " ofs-delta");
 305                         if (deepen_since_ok)    strbuf_addstr(&c, " deepen-since");
 306                         if (deepen_not_ok)      strbuf_addstr(&c, " deepen-not");
 307                         if (agent_supported)    strbuf_addf(&c, " agent=%s",
 308                                                             git_user_agent_sanitized());
 309                         if (args->filter_options.choice)
 310                                 strbuf_addstr(&c, " filter");
 311                         packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
 312                         strbuf_release(&c);
 313                 } else
 314                         packet_buf_write(&req_buf, "want %s\n", remote_hex);
 315                 fetching++;
 316         }
 317
 318         if (!fetching) {
 319                 strbuf_release(&req_buf);
 320                 packet_flush(fd[1]);
 321                 return 1;
 322         }
 323
 324         if (is_repository_shallow(the_repository))
 325                 write_shallow_commits(&req_buf, 1, NULL);
 326         if (args->depth > 0)
 327                 packet_buf_write(&req_buf, "deepen %d", args->depth);
 328         if (args->deepen_since) {
 329                 timestamp_t max_age = approxidate(args->deepen_since);
 330                 packet_buf_write(&req_buf, "deepen-since %"PRItime, max_age);
 331         }
 332         if (args->deepen_not) {
 333                 int i;
 334                 for (i = 0; i < args->deepen_not->nr; i++) {
 335                         struct string_list_item *s = args->deepen_not->items + i;
 336                         packet_buf_write(&req_buf, "deepen-not %s", s->string);
 337                 }
 338         }
 339         if (server_supports_filtering && args->filter_options.choice)
 340                 packet_buf_write(&req_buf, "filter %s",
 341                                  args->filter_options.filter_spec);
 342         packet_buf_flush(&req_buf);
 343         state_len = req_buf.len;
 344
 345         if (args->deepen) {
 346                 const char *arg;
 347                 struct object_id oid;
 348
 349                 send_request(args, fd[1], &req_buf);
 350                 while (packet_reader_read(&reader) == PACKET_READ_NORMAL) {
 351                         if (skip_prefix(reader.line, "shallow ", &arg)) {
 352                                 if (get_oid_hex(arg, &oid))
 353                                         die(_("invalid shallow line: %s"), reader.line);
 354                                 register_shallow(the_repository, &oid);
 355                                 continue;
 356                         }
 357                         if (skip_prefix(reader.line, "unshallow ", &arg)) {
 358                                 if (get_oid_hex(arg, &oid))
 359                                         die(_("invalid unshallow line: %s"), reader.line);
 360                                 if (!lookup_object(the_repository, oid.hash))
 361                                         die(_("object not found: %s"), reader.line);
 362                                 /* make sure that it is parsed as shallow */
 363                                 if (!parse_object(the_repository, &oid))
 364                                         die(_("error in object: %s"), reader.line);
 365                                 if (unregister_shallow(&oid))
 366                                         die(_("no shallow found: %s"), reader.line);
 367                                 continue;
 368                         }
 369                         die(_("expected shallow/unshallow, got %s"), reader.line);
 370                 }
 371         } else if (!args->stateless_rpc)
 372                 send_request(args, fd[1], &req_buf);
 373
 374         if (!args->stateless_rpc) {
 375                 /* If we aren't using the stateless-rpc interface
 376                  * we don't need to retain the headers.
 377                  */
 378                 strbuf_setlen(&req_buf, 0);
 379                 state_len = 0;
 380         }
 381
 382         flushes = 0;
 383         retval = -1;
 384         if (args->no_dependents)
 385                 goto done;
 386         while ((oid = negotiator->next(negotiator))) {
 387                 packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid));
 388                 print_verbose(args, "have %s", oid_to_hex(oid));
 389                 in_vain++;
 390                 if (flush_at <= ++count) {
 391                         int ack;
 392
 393                         packet_buf_flush(&req_buf);
 394                         send_request(args, fd[1], &req_buf);
 395                         strbuf_setlen(&req_buf, state_len);
 396                         flushes++;
 397                         flush_at = next_flush(args->stateless_rpc, count);
 398
 399                         /*
 400                          * We keep one window "ahead" of the other side, and
 401                          * will wait for an ACK only on the next one
 402                          */
 403                         if (!args->stateless_rpc && count == INITIAL_FLUSH)
 404                                 continue;
 405
 406                         consume_shallow_list(args, &reader);
 407                         do {
 408                                 ack = get_ack(&reader, result_oid);
 409                                 if (ack)
 410                                         print_verbose(args, _("got %s %d %s"), "ack",
 411                                                       ack, oid_to_hex(result_oid));
 412                                 switch (ack) {
 413                                 case ACK:
 414                                         flushes = 0;
 415                                         multi_ack = 0;
 416                                         retval = 0;
 417                                         goto done;
 418                                 case ACK_common:
 419                                 case ACK_ready:
 420                                 case ACK_continue: {
 421                                         struct commit *commit =
 422                                                 lookup_commit(the_repository,
 423                                                               result_oid);
 424                                         int was_common;
 425
 426                                         if (!commit)
 427                                                 die(_("invalid commit %s"), oid_to_hex(result_oid));
 428                                         was_common = negotiator->ack(negotiator, commit);
 429                                         if (args->stateless_rpc
 430                                          && ack == ACK_common
 431                                          && !was_common) {
 432                                                 /* We need to replay the have for this object
 433                                                  * on the next RPC request so the peer knows
 434                                                  * it is in common with us.
 435                                                  */
 436                                                 const char *hex = oid_to_hex(result_oid);
 437                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 438                                                 state_len = req_buf.len;
 439                                                 /*
 440                                                  * Reset in_vain because an ack
 441                                                  * for this commit has not been
 442                                                  * seen.
 443                                                  */
 444                                                 in_vain = 0;
 445                                         } else if (!args->stateless_rpc
 446                                                    || ack != ACK_common)
 447                                                 in_vain = 0;
 448                                         retval = 0;
 449                                         got_continue = 1;
 450                                         if (ack == ACK_ready)
 451                                                 got_ready = 1;
 452                                         break;
 453                                         }
 454                                 }
 455                         } while (ack);
 456                         flushes--;
 457                         if (got_continue && MAX_IN_VAIN < in_vain) {
 458                                 print_verbose(args, _("giving up"));
 459                                 break; /* give up */
 460                         }
 461                         if (got_ready)
 462                                 break;
 463                 }
 464         }
 465 done:
 466         if (!got_ready || !no_done) {
 467                 packet_buf_write(&req_buf, "done\n");
 468                 send_request(args, fd[1], &req_buf);
 469         }
 470         print_verbose(args, _("done"));
 471         if (retval != 0) {
 472                 multi_ack = 0;
 473                 flushes++;
 474         }
 475         strbuf_release(&req_buf);
 476
 477         if (!got_ready || !no_done)
 478                 consume_shallow_list(args, &reader);
 479         while (flushes || multi_ack) {
 480                 int ack = get_ack(&reader, result_oid);
 481                 if (ack) {
 482                         print_verbose(args, _("got %s (%d) %s"), "ack",
 483                                       ack, oid_to_hex(result_oid));
 484                         if (ack == ACK)
 485                                 return 0;
 486                         multi_ack = 1;
 487                         continue;
 488                 }
 489                 flushes--;
 490         }
 491         /* it is no error to fetch into a completely empty repo */
 492         return count ? retval : 0;
 493 }
 494
 495 static struct commit_list *complete;
 496
 497 static int mark_complete(const struct object_id *oid)
 498 {
 499         struct object *o = parse_object(the_repository, oid);
 500
 501         while (o && o->type == OBJ_TAG) {
 502                 struct tag *t = (struct tag *) o;
 503                 if (!t->tagged)
 504                         break; /* broken repository */
 505                 o->flags |= COMPLETE;
 506                 o = parse_object(the_repository, &t->tagged->oid);
 507         }
 508         if (o && o->type == OBJ_COMMIT) {
 509                 struct commit *commit = (struct commit *)o;
 510                 if (!(commit->object.flags & COMPLETE)) {
 511                         commit->object.flags |= COMPLETE;
 512                         commit_list_insert(commit, &complete);
 513                 }
 514         }
 515         return 0;
 516 }
 517
 518 static int mark_complete_oid(const char *refname, const struct object_id *oid,
 519                              int flag, void *cb_data)
 520 {
 521         return mark_complete(oid);
 522 }
 523
 524 static void mark_recent_complete_commits(struct fetch_pack_args *args,
 525                                          timestamp_t cutoff)
 526 {
 527         while (complete && cutoff <= complete->item->date) {
 528                 print_verbose(args, _("Marking %s as complete"),
 529                               oid_to_hex(&complete->item->object.oid));
 530                 pop_most_recent_commit(&complete, COMPLETE);
 531         }
 532 }
 533
 534 static void add_refs_to_oidset(struct oidset *oids, struct ref *refs)
 535 {
 536         for (; refs; refs = refs->next)
 537                 oidset_insert(oids, &refs->old_oid);
 538 }
 539
 540 static int is_unmatched_ref(const struct ref *ref)
 541 {
 542         struct object_id oid;
 543         const char *p;
 544         return  ref->match_status == REF_NOT_MATCHED &&
 545                 !parse_oid_hex(ref->name, &oid, &p) &&
 546                 *p == '\0' &&
 547                 oideq(&oid, &ref->old_oid);
 548 }
 549
 550 static void filter_refs(struct fetch_pack_args *args,
 551                         struct ref **refs,
 552                         struct ref **sought, int nr_sought)
 553 {
 554         struct ref *newlist = NULL;
 555         struct ref **newtail = &newlist;
 556         struct ref *unmatched = NULL;
 557         struct ref *ref, *next;
 558         struct oidset tip_oids = OIDSET_INIT;
 559         int i;
 560         int strict = !(allow_unadvertised_object_request &
 561                        (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1));
 562
 563         i = 0;
 564         for (ref = *refs; ref; ref = next) {
 565                 int keep = 0;
 566                 next = ref->next;
 567
 568                 if (starts_with(ref->name, "refs/") &&
 569                     check_refname_format(ref->name, 0))
 570                         ; /* trash */
 571                 else {
 572                         while (i < nr_sought) {
 573                                 int cmp = strcmp(ref->name, sought[i]->name);
 574                                 if (cmp < 0)
 575                                         break; /* definitely do not have it */
 576                                 else if (cmp == 0) {
 577                                         keep = 1; /* definitely have it */
 578                                         sought[i]->match_status = REF_MATCHED;
 579                                 }
 580                                 i++;
 581                         }
 582
 583                         if (!keep && args->fetch_all &&
 584                             (!args->deepen || !starts_with(ref->name, "refs/tags/")))
 585                                 keep = 1;
 586                 }
 587
 588                 if (keep) {
 589                         *newtail = ref;
 590                         ref->next = NULL;
 591                         newtail = &ref->next;
 592                 } else {
 593                         ref->next = unmatched;
 594                         unmatched = ref;
 595                 }
 596         }
 597
 598         if (strict) {
 599                 for (i = 0; i < nr_sought; i++) {
 600                         ref = sought[i];
 601                         if (!is_unmatched_ref(ref))
 602                                 continue;
 603
 604                         add_refs_to_oidset(&tip_oids, unmatched);
 605                         add_refs_to_oidset(&tip_oids, newlist);
 606                         break;
 607                 }
 608         }
 609
 610         /* Append unmatched requests to the list */
 611         for (i = 0; i < nr_sought; i++) {
 612                 ref = sought[i];
 613                 if (!is_unmatched_ref(ref))
 614                         continue;
 615
 616                 if (!strict || oidset_contains(&tip_oids, &ref->old_oid)) {
 617                         ref->match_status = REF_MATCHED;
 618                         *newtail = copy_ref(ref);
 619                         newtail = &(*newtail)->next;
 620                 } else {
 621                         ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
 622                 }
 623         }
 624
 625         oidset_clear(&tip_oids);
 626         for (ref = unmatched; ref; ref = next) {
 627                 next = ref->next;
 628                 free(ref);
 629         }
 630
 631         *refs = newlist;
 632 }
 633
 634 static void mark_alternate_complete(struct fetch_negotiator *unused,
 635                                     struct object *obj)
 636 {
 637         mark_complete(&obj->oid);
 638 }
 639
 640 struct loose_object_iter {
 641         struct oidset *loose_object_set;
 642         struct ref *refs;
 643 };
 644
 645 /*
 646  *  If the number of refs is not larger than the number of loose objects,
 647  *  this function stops inserting.
 648  */
 649 static int add_loose_objects_to_set(const struct object_id *oid,
 650                                     const char *path,
 651                                     void *data)
 652 {
 653         struct loose_object_iter *iter = data;
 654         oidset_insert(iter->loose_object_set, oid);
 655         if (iter->refs == NULL)
 656                 return 1;
 657
 658         iter->refs = iter->refs->next;
 659         return 0;
 660 }
 661
 662 /*
 663  * Mark recent commits available locally and reachable from a local ref as
 664  * COMPLETE. If args->no_dependents is false, also mark COMPLETE remote refs as
 665  * COMMON_REF (otherwise, we are not planning to participate in negotiation, and
 666  * thus do not need COMMON_REF marks).
 667  *
 668  * The cutoff time for recency is determined by this heuristic: it is the
 669  * earliest commit time of the objects in refs that are commits and that we know
 670  * the commit time of.
 671  */
 672 static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
 673                                          struct fetch_pack_args *args,
 674                                          struct ref **refs)
 675 {
 676         struct ref *ref;
 677         int old_save_commit_buffer = save_commit_buffer;
 678         timestamp_t cutoff = 0;
 679         struct oidset loose_oid_set = OIDSET_INIT;
 680         int use_oidset = 0;
 681         struct loose_object_iter iter = {&loose_oid_set, *refs};
 682
 683         /* Enumerate all loose objects or know refs are not so many. */
 684         use_oidset = !for_each_loose_object(add_loose_objects_to_set,
 685                                             &iter, 0);
 686
 687         save_commit_buffer = 0;
 688
 689         for (ref = *refs; ref; ref = ref->next) {
 690                 struct object *o;
 691                 unsigned int flags = OBJECT_INFO_QUICK;
 692
 693                 if (use_oidset &&
 694                     !oidset_contains(&loose_oid_set, &ref->old_oid)) {
 695                         /*
 696                          * I know this does not exist in the loose form,
 697                          * so check if it exists in a non-loose form.
 698                          */
 699                         flags |= OBJECT_INFO_IGNORE_LOOSE;
 700                 }
 701
 702                 if (!has_object_file_with_flags(&ref->old_oid, flags))
 703                         continue;
 704                 o = parse_object(the_repository, &ref->old_oid);
 705                 if (!o)
 706                         continue;
 707
 708                 /* We already have it -- which may mean that we were
 709                  * in sync with the other side at some time after
 710                  * that (it is OK if we guess wrong here).
 711                  */
 712                 if (o->type == OBJ_COMMIT) {
 713                         struct commit *commit = (struct commit *)o;
 714                         if (!cutoff || cutoff < commit->date)
 715                                 cutoff = commit->date;
 716                 }
 717         }
 718
 719         oidset_clear(&loose_oid_set);
 720
 721         if (!args->deepen) {
 722                 for_each_ref(mark_complete_oid, NULL);
 723                 for_each_cached_alternate(NULL, mark_alternate_complete);
 724                 commit_list_sort_by_date(&complete);
 725                 if (cutoff)
 726                         mark_recent_complete_commits(args, cutoff);
 727         }
 728
 729         /*
 730          * Mark all complete remote refs as common refs.
 731          * Don't mark them common yet; the server has to be told so first.
 732          */
 733         for (ref = *refs; ref; ref = ref->next) {
 734                 struct object *o = deref_tag(the_repository,
 735                                              lookup_object(the_repository,
 736                                              ref->old_oid.hash),
 737                                              NULL, 0);
 738
 739                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 740                         continue;
 741
 742                 negotiator->known_common(negotiator,
 743                                          (struct commit *)o);
 744         }
 745
 746         save_commit_buffer = old_save_commit_buffer;
 747 }
 748
 749 /*
 750  * Returns 1 if every object pointed to by the given remote refs is available
 751  * locally and reachable from a local ref, and 0 otherwise.
 752  */
 753 static int everything_local(struct fetch_pack_args *args,
 754                             struct ref **refs)
 755 {
 756         struct ref *ref;
 757         int retval;
 758
 759         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 760                 const struct object_id *remote = &ref->old_oid;
 761                 struct object *o;
 762
 763                 o = lookup_object(the_repository, remote->hash);
 764                 if (!o || !(o->flags & COMPLETE)) {
 765                         retval = 0;
 766                         print_verbose(args, "want %s (%s)", oid_to_hex(remote),
 767                                       ref->name);
 768                         continue;
 769                 }
 770                 print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
 771                               ref->name);
 772         }
 773
 774         return retval;
 775 }
 776
 777 static int sideband_demux(int in, int out, void *data)
 778 {
 779         int *xd = data;
 780         int ret;
 781
 782         ret = recv_sideband("fetch-pack", xd[0], out);
 783         close(out);
 784         return ret;
 785 }
 786
 787 static int get_pack(struct fetch_pack_args *args,
 788                     int xd[2], char **pack_lockfile)
 789 {
 790         struct async demux;
 791         int do_keep = args->keep_pack;
 792         const char *cmd_name;
 793         struct pack_header header;
 794         int pass_header = 0;
 795         struct child_process cmd = CHILD_PROCESS_INIT;
 796         int ret;
 797
 798         memset(&demux, 0, sizeof(demux));
 799         if (use_sideband) {
 800                 /* xd[] is talking with upload-pack; subprocess reads from
 801                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 802                  * through demux->out.
 803                  */
 804                 demux.proc = sideband_demux;
 805                 demux.data = xd;
 806                 demux.out = -1;
 807                 demux.isolate_sigpipe = 1;
 808                 if (start_async(&demux))
 809                         die(_("fetch-pack: unable to fork off sideband demultiplexer"));
 810         }
 811         else
 812                 demux.out = xd[0];
 813
 814         if (!args->keep_pack && unpack_limit) {
 815
 816                 if (read_pack_header(demux.out, &header))
 817                         die(_("protocol error: bad pack header"));
 818                 pass_header = 1;
 819                 if (ntohl(header.hdr_entries) < unpack_limit)
 820                         do_keep = 0;
 821                 else
 822                         do_keep = 1;
 823         }
 824
 825         if (alternate_shallow_file) {
 826                 argv_array_push(&cmd.args, "--shallow-file");
 827                 argv_array_push(&cmd.args, alternate_shallow_file);
 828         }
 829
 830         if (do_keep || args->from_promisor) {
 831                 if (pack_lockfile)
 832                         cmd.out = -1;
 833                 cmd_name = "index-pack";
 834                 argv_array_push(&cmd.args, cmd_name);
 835                 argv_array_push(&cmd.args, "--stdin");
 836                 if (!args->quiet && !args->no_progress)
 837                         argv_array_push(&cmd.args, "-v");
 838                 if (args->use_thin_pack)
 839                         argv_array_push(&cmd.args, "--fix-thin");
 840                 if (do_keep && (args->lock_pack || unpack_limit)) {
 841                         char hostname[HOST_NAME_MAX + 1];
 842                         if (xgethostname(hostname, sizeof(hostname)))
 843                                 xsnprintf(hostname, sizeof(hostname), "localhost");
 844                         argv_array_pushf(&cmd.args,
 845                                         "--keep=fetch-pack %"PRIuMAX " on %s",
 846                                         (uintmax_t)getpid(), hostname);
 847                 }
 848                 if (args->check_self_contained_and_connected)
 849                         argv_array_push(&cmd.args, "--check-self-contained-and-connected");
 850                 if (args->from_promisor)
 851                         argv_array_push(&cmd.args, "--promisor");
 852         }
 853         else {
 854                 cmd_name = "unpack-objects";
 855                 argv_array_push(&cmd.args, cmd_name);
 856                 if (args->quiet || args->no_progress)
 857                         argv_array_push(&cmd.args, "-q");
 858                 args->check_self_contained_and_connected = 0;
 859         }
 860
 861         if (pass_header)
 862                 argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
 863                                  ntohl(header.hdr_version),
 864                                  ntohl(header.hdr_entries));
 865         if (fetch_fsck_objects >= 0
 866             ? fetch_fsck_objects
 867             : transfer_fsck_objects >= 0
 868             ? transfer_fsck_objects
 869             : 0) {
 870                 if (args->from_promisor)
 871                         /*
 872                          * We cannot use --strict in index-pack because it
 873                          * checks both broken objects and links, but we only
 874                          * want to check for broken objects.
 875                          */
 876                         argv_array_push(&cmd.args, "--fsck-objects");
 877                 else
 878                         argv_array_pushf(&cmd.args, "--strict%s",
 879                                          fsck_msg_types.buf);
 880         }
 881
 882         cmd.in = demux.out;
 883         cmd.git_cmd = 1;
 884         if (start_command(&cmd))
 885                 die(_("fetch-pack: unable to fork off %s"), cmd_name);
 886         if (do_keep && pack_lockfile) {
 887                 *pack_lockfile = index_pack_lockfile(cmd.out);
 888                 close(cmd.out);
 889         }
 890
 891         if (!use_sideband)
 892                 /* Closed by start_command() */
 893                 xd[0] = -1;
 894
 895         ret = finish_command(&cmd);
 896         if (!ret || (args->check_self_contained_and_connected && ret == 1))
 897                 args->self_contained_and_connected =
 898                         args->check_self_contained_and_connected &&
 899                         ret == 0;
 900         else
 901                 die(_("%s failed"), cmd_name);
 902         if (use_sideband && finish_async(&demux))
 903                 die(_("error in sideband demultiplexer"));
 904         return 0;
 905 }
 906
 907 static int cmp_ref_by_name(const void *a_, const void *b_)
 908 {
 909         const struct ref *a = *((const struct ref **)a_);
 910         const struct ref *b = *((const struct ref **)b_);
 911         return strcmp(a->name, b->name);
 912 }
 913
 914 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 915                                  int fd[2],
 916                                  const struct ref *orig_ref,
 917                                  struct ref **sought, int nr_sought,
 918                                  struct shallow_info *si,
 919                                  char **pack_lockfile)
 920 {
 921         struct ref *ref = copy_ref_list(orig_ref);
 922         struct object_id oid;
 923         const char *agent_feature;
 924         int agent_len;
 925         struct fetch_negotiator negotiator;
 926         fetch_negotiator_init(&negotiator, negotiation_algorithm);
 927
 928         sort_ref_list(&ref, ref_compare_name);
 929         QSORT(sought, nr_sought, cmp_ref_by_name);
 930
 931         if ((args->depth > 0 || is_repository_shallow(the_repository)) && !server_supports("shallow"))
 932                 die(_("Server does not support shallow clients"));
 933         if (args->depth > 0 || args->deepen_since || args->deepen_not)
 934                 args->deepen = 1;
 935         if (server_supports("multi_ack_detailed")) {
 936                 print_verbose(args, _("Server supports multi_ack_detailed"));
 937                 multi_ack = 2;
 938                 if (server_supports("no-done")) {
 939                         print_verbose(args, _("Server supports no-done"));
 940                         if (args->stateless_rpc)
 941                                 no_done = 1;
 942                 }
 943         }
 944         else if (server_supports("multi_ack")) {
 945                 print_verbose(args, _("Server supports multi_ack"));
 946                 multi_ack = 1;
 947         }
 948         if (server_supports("side-band-64k")) {
 949                 print_verbose(args, _("Server supports side-band-64k"));
 950                 use_sideband = 2;
 951         }
 952         else if (server_supports("side-band")) {
 953                 print_verbose(args, _("Server supports side-band"));
 954                 use_sideband = 1;
 955         }
 956         if (server_supports("allow-tip-sha1-in-want")) {
 957                 print_verbose(args, _("Server supports allow-tip-sha1-in-want"));
 958                 allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
 959         }
 960         if (server_supports("allow-reachable-sha1-in-want")) {
 961                 print_verbose(args, _("Server supports allow-reachable-sha1-in-want"));
 962                 allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
 963         }
 964         if (!server_supports("thin-pack"))
 965                 args->use_thin_pack = 0;
 966         if (!server_supports("no-progress"))
 967                 args->no_progress = 0;
 968         if (!server_supports("include-tag"))
 969                 args->include_tag = 0;
 970         if (server_supports("ofs-delta"))
 971                 print_verbose(args, _("Server supports ofs-delta"));
 972         else
 973                 prefer_ofs_delta = 0;
 974
 975         if (server_supports("filter")) {
 976                 server_supports_filtering = 1;
 977                 print_verbose(args, _("Server supports filter"));
 978         } else if (args->filter_options.choice) {
 979                 warning("filtering not recognized by server, ignoring");
 980         }
 981
 982         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 983                 agent_supported = 1;
 984                 if (agent_len)
 985                         print_verbose(args, _("Server version is %.*s"),
 986                                       agent_len, agent_feature);
 987         }
 988         if (server_supports("deepen-since"))
 989                 deepen_since_ok = 1;
 990         else if (args->deepen_since)
 991                 die(_("Server does not support --shallow-since"));
 992         if (server_supports("deepen-not"))
 993                 deepen_not_ok = 1;
 994         else if (args->deepen_not)
 995                 die(_("Server does not support --shallow-exclude"));
 996         if (!server_supports("deepen-relative") && args->deepen_relative)
 997                 die(_("Server does not support --deepen"));
 998
 999         if (!args->no_dependents) {
1000                 mark_complete_and_common_ref(&negotiator, args, &ref);
1001                 filter_refs(args, &ref, sought, nr_sought);
1002                 if (everything_local(args, &ref)) {
1003                         packet_flush(fd[1]);
1004                         goto all_done;
1005                 }
1006         } else {
1007                 filter_refs(args, &ref, sought, nr_sought);
1008         }
1009         if (find_common(&negotiator, args, fd, &oid, ref) < 0)
1010                 if (!args->keep_pack)
1011                         /* When cloning, it is not unusual to have
1012                          * no common commit.
1013                          */
1014                         warning(_("no common commits"));
1015
1016         if (args->stateless_rpc)
1017                 packet_flush(fd[1]);
1018         if (args->deepen)
1019                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
1020                                         NULL);
1021         else if (si->nr_ours || si->nr_theirs)
1022                 alternate_shallow_file = setup_temporary_shallow(si->shallow);
1023         else
1024                 alternate_shallow_file = NULL;
1025         if (get_pack(args, fd, pack_lockfile))
1026                 die(_("git fetch-pack: fetch failed."));
1027
1028  all_done:
1029         negotiator.release(&negotiator);
1030         return ref;
1031 }
1032
1033 static void add_shallow_requests(struct strbuf *req_buf,
1034                                  const struct fetch_pack_args *args)
1035 {
1036         if (is_repository_shallow(the_repository))
1037                 write_shallow_commits(req_buf, 1, NULL);
1038         if (args->depth > 0)
1039                 packet_buf_write(req_buf, "deepen %d", args->depth);
1040         if (args->deepen_since) {
1041                 timestamp_t max_age = approxidate(args->deepen_since);
1042                 packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
1043         }
1044         if (args->deepen_not) {
1045                 int i;
1046                 for (i = 0; i < args->deepen_not->nr; i++) {
1047                         struct string_list_item *s = args->deepen_not->items + i;
1048                         packet_buf_write(req_buf, "deepen-not %s", s->string);
1049                 }
1050         }
1051 }
1052
1053 static void add_wants(int no_dependents, const struct ref *wants, struct strbuf *req_buf)
1054 {
1055         int use_ref_in_want = server_supports_feature("fetch", "ref-in-want", 0);
1056
1057         for ( ; wants ; wants = wants->next) {
1058                 const struct object_id *remote = &wants->old_oid;
1059                 struct object *o;
1060
1061                 /*
1062                  * If that object is complete (i.e. it is an ancestor of a
1063                  * local ref), we tell them we have it but do not have to
1064                  * tell them about its ancestors, which they already know
1065                  * about.
1066                  *
1067                  * We use lookup_object here because we are only
1068                  * interested in the case we *know* the object is
1069                  * reachable and we have already scanned it.
1070                  *
1071                  * Do this only if args->no_dependents is false (if it is true,
1072                  * we cannot trust the object flags).
1073                  */
1074                 if (!no_dependents &&
1075                     ((o = lookup_object(the_repository, remote->hash)) != NULL) &&
1076                     (o->flags & COMPLETE)) {
1077                         continue;
1078                 }
1079
1080                 if (!use_ref_in_want || wants->exact_oid)
1081                         packet_buf_write(req_buf, "want %s\n", oid_to_hex(remote));
1082                 else
1083                         packet_buf_write(req_buf, "want-ref %s\n", wants->name);
1084         }
1085 }
1086
1087 static void add_common(struct strbuf *req_buf, struct oidset *common)
1088 {
1089         struct oidset_iter iter;
1090         const struct object_id *oid;
1091         oidset_iter_init(common, &iter);
1092
1093         while ((oid = oidset_iter_next(&iter))) {
1094                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1095         }
1096 }
1097
1098 static int add_haves(struct fetch_negotiator *negotiator,
1099                      struct strbuf *req_buf,
1100                      int *haves_to_send, int *in_vain)
1101 {
1102         int ret = 0;
1103         int haves_added = 0;
1104         const struct object_id *oid;
1105
1106         while ((oid = negotiator->next(negotiator))) {
1107                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1108                 if (++haves_added >= *haves_to_send)
1109                         break;
1110         }
1111
1112         *in_vain += haves_added;
1113         if (!haves_added || *in_vain >= MAX_IN_VAIN) {
1114                 /* Send Done */
1115                 packet_buf_write(req_buf, "done\n");
1116                 ret = 1;
1117         }
1118
1119         /* Increase haves to send on next round */
1120         *haves_to_send = next_flush(1, *haves_to_send);
1121
1122         return ret;
1123 }
1124
1125 static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
1126                               const struct fetch_pack_args *args,
1127                               const struct ref *wants, struct oidset *common,
1128                               int *haves_to_send, int *in_vain)
1129 {
1130         int ret = 0;
1131         struct strbuf req_buf = STRBUF_INIT;
1132
1133         if (server_supports_v2("fetch", 1))
1134                 packet_buf_write(&req_buf, "command=fetch");
1135         if (server_supports_v2("agent", 0))
1136                 packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
1137         if (args->server_options && args->server_options->nr &&
1138             server_supports_v2("server-option", 1)) {
1139                 int i;
1140                 for (i = 0; i < args->server_options->nr; i++)
1141                         packet_write_fmt(fd_out, "server-option=%s",
1142                                          args->server_options->items[i].string);
1143         }
1144
1145         packet_buf_delim(&req_buf);
1146         if (args->use_thin_pack)
1147                 packet_buf_write(&req_buf, "thin-pack");
1148         if (args->no_progress)
1149                 packet_buf_write(&req_buf, "no-progress");
1150         if (args->include_tag)
1151                 packet_buf_write(&req_buf, "include-tag");
1152         if (prefer_ofs_delta)
1153                 packet_buf_write(&req_buf, "ofs-delta");
1154
1155         /* Add shallow-info and deepen request */
1156         if (server_supports_feature("fetch", "shallow", 0))
1157                 add_shallow_requests(&req_buf, args);
1158         else if (is_repository_shallow(the_repository) || args->deepen)
1159                 die(_("Server does not support shallow requests"));
1160
1161         /* Add filter */
1162         if (server_supports_feature("fetch", "filter", 0) &&
1163             args->filter_options.choice) {
1164                 print_verbose(args, _("Server supports filter"));
1165                 packet_buf_write(&req_buf, "filter %s",
1166                                  args->filter_options.filter_spec);
1167         } else if (args->filter_options.choice) {
1168                 warning("filtering not recognized by server, ignoring");
1169         }
1170
1171         /* add wants */
1172         add_wants(args->no_dependents, wants, &req_buf);
1173
1174         if (args->no_dependents) {
1175                 packet_buf_write(&req_buf, "done");
1176                 ret = 1;
1177         } else {
1178                 /* Add all of the common commits we've found in previous rounds */
1179                 add_common(&req_buf, common);
1180
1181                 /* Add initial haves */
1182                 ret = add_haves(negotiator, &req_buf, haves_to_send, in_vain);
1183         }
1184
1185         /* Send request */
1186         packet_buf_flush(&req_buf);
1187         write_or_die(fd_out, req_buf.buf, req_buf.len);
1188
1189         strbuf_release(&req_buf);
1190         return ret;
1191 }
1192
1193 /*
1194  * Processes a section header in a server's response and checks if it matches
1195  * `section`.  If the value of `peek` is 1, the header line will be peeked (and
1196  * not consumed); if 0, the line will be consumed and the function will die if
1197  * the section header doesn't match what was expected.
1198  */
1199 static int process_section_header(struct packet_reader *reader,
1200                                   const char *section, int peek)
1201 {
1202         int ret;
1203
1204         if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
1205                 die(_("error reading section header '%s'"), section);
1206
1207         ret = !strcmp(reader->line, section);
1208
1209         if (!peek) {
1210                 if (!ret)
1211                         die(_("expected '%s', received '%s'"),
1212                             section, reader->line);
1213                 packet_reader_read(reader);
1214         }
1215
1216         return ret;
1217 }
1218
1219 static int process_acks(struct fetch_negotiator *negotiator,
1220                         struct packet_reader *reader,
1221                         struct oidset *common)
1222 {
1223         /* received */
1224         int received_ready = 0;
1225         int received_ack = 0;
1226
1227         process_section_header(reader, "acknowledgments", 0);
1228         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1229                 const char *arg;
1230
1231                 if (!strcmp(reader->line, "NAK"))
1232                         continue;
1233
1234                 if (skip_prefix(reader->line, "ACK ", &arg)) {
1235                         struct object_id oid;
1236                         if (!get_oid_hex(arg, &oid)) {
1237                                 struct commit *commit;
1238                                 oidset_insert(common, &oid);
1239                                 commit = lookup_commit(the_repository, &oid);
1240                                 negotiator->ack(negotiator, commit);
1241                         }
1242                         continue;
1243                 }
1244
1245                 if (!strcmp(reader->line, "ready")) {
1246                         received_ready = 1;
1247                         continue;
1248                 }
1249
1250                 die(_("unexpected acknowledgment line: '%s'"), reader->line);
1251         }
1252
1253         if (reader->status != PACKET_READ_FLUSH &&
1254             reader->status != PACKET_READ_DELIM)
1255                 die(_("error processing acks: %d"), reader->status);
1256
1257         /*
1258          * If an "acknowledgments" section is sent, a packfile is sent if and
1259          * only if "ready" was sent in this section. The other sections
1260          * ("shallow-info" and "wanted-refs") are sent only if a packfile is
1261          * sent. Therefore, a DELIM is expected if "ready" is sent, and a FLUSH
1262          * otherwise.
1263          */
1264         if (received_ready && reader->status != PACKET_READ_DELIM)
1265                 die(_("expected packfile to be sent after 'ready'"));
1266         if (!received_ready && reader->status != PACKET_READ_FLUSH)
1267                 die(_("expected no other sections to be sent after no 'ready'"));
1268
1269         /* return 0 if no common, 1 if there are common, or 2 if ready */
1270         return received_ready ? 2 : (received_ack ? 1 : 0);
1271 }
1272
1273 static void receive_shallow_info(struct fetch_pack_args *args,
1274                                  struct packet_reader *reader)
1275 {
1276         process_section_header(reader, "shallow-info", 0);
1277         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1278                 const char *arg;
1279                 struct object_id oid;
1280
1281                 if (skip_prefix(reader->line, "shallow ", &arg)) {
1282                         if (get_oid_hex(arg, &oid))
1283                                 die(_("invalid shallow line: %s"), reader->line);
1284                         register_shallow(the_repository, &oid);
1285                         continue;
1286                 }
1287                 if (skip_prefix(reader->line, "unshallow ", &arg)) {
1288                         if (get_oid_hex(arg, &oid))
1289                                 die(_("invalid unshallow line: %s"), reader->line);
1290                         if (!lookup_object(the_repository, oid.hash))
1291                                 die(_("object not found: %s"), reader->line);
1292                         /* make sure that it is parsed as shallow */
1293                         if (!parse_object(the_repository, &oid))
1294                                 die(_("error in object: %s"), reader->line);
1295                         if (unregister_shallow(&oid))
1296                                 die(_("no shallow found: %s"), reader->line);
1297                         continue;
1298                 }
1299                 die(_("expected shallow/unshallow, got %s"), reader->line);
1300         }
1301
1302         if (reader->status != PACKET_READ_FLUSH &&
1303             reader->status != PACKET_READ_DELIM)
1304                 die(_("error processing shallow info: %d"), reader->status);
1305
1306         setup_alternate_shallow(&shallow_lock, &alternate_shallow_file, NULL);
1307         args->deepen = 1;
1308 }
1309
1310 static void receive_wanted_refs(struct packet_reader *reader,
1311                                 struct ref **sought, int nr_sought)
1312 {
1313         process_section_header(reader, "wanted-refs", 0);
1314         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1315                 struct object_id oid;
1316                 const char *end;
1317                 int i;
1318
1319                 if (parse_oid_hex(reader->line, &oid, &end) || *end++ != ' ')
1320                         die(_("expected wanted-ref, got '%s'"), reader->line);
1321
1322                 for (i = 0; i < nr_sought; i++) {
1323                         if (!strcmp(end, sought[i]->name)) {
1324                                 oidcpy(&sought[i]->old_oid, &oid);
1325                                 break;
1326                         }
1327                 }
1328
1329                 if (i == nr_sought)
1330                         die(_("unexpected wanted-ref: '%s'"), reader->line);
1331         }
1332
1333         if (reader->status != PACKET_READ_DELIM)
1334                 die(_("error processing wanted refs: %d"), reader->status);
1335 }
1336
1337 enum fetch_state {
1338         FETCH_CHECK_LOCAL = 0,
1339         FETCH_SEND_REQUEST,
1340         FETCH_PROCESS_ACKS,
1341         FETCH_GET_PACK,
1342         FETCH_DONE,
1343 };
1344
1345 static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
1346                                     int fd[2],
1347                                     const struct ref *orig_ref,
1348                                     struct ref **sought, int nr_sought,
1349                                     char **pack_lockfile)
1350 {
1351         struct ref *ref = copy_ref_list(orig_ref);
1352         enum fetch_state state = FETCH_CHECK_LOCAL;
1353         struct oidset common = OIDSET_INIT;
1354         struct packet_reader reader;
1355         int in_vain = 0;
1356         int haves_to_send = INITIAL_FLUSH;
1357         struct fetch_negotiator negotiator;
1358         fetch_negotiator_init(&negotiator, negotiation_algorithm);
1359         packet_reader_init(&reader, fd[0], NULL, 0,
1360                            PACKET_READ_CHOMP_NEWLINE |
1361                            PACKET_READ_DIE_ON_ERR_PACKET);
1362
1363         while (state != FETCH_DONE) {
1364                 switch (state) {
1365                 case FETCH_CHECK_LOCAL:
1366                         sort_ref_list(&ref, ref_compare_name);
1367                         QSORT(sought, nr_sought, cmp_ref_by_name);
1368
1369                         /* v2 supports these by default */
1370                         allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
1371                         use_sideband = 2;
1372                         if (args->depth > 0 || args->deepen_since || args->deepen_not)
1373                                 args->deepen = 1;
1374
1375                         /* Filter 'ref' by 'sought' and those that aren't local */
1376                         if (!args->no_dependents) {
1377                                 mark_complete_and_common_ref(&negotiator, args, &ref);
1378                                 filter_refs(args, &ref, sought, nr_sought);
1379                                 if (everything_local(args, &ref))
1380                                         state = FETCH_DONE;
1381                                 else
1382                                         state = FETCH_SEND_REQUEST;
1383
1384                                 mark_tips(&negotiator, args->negotiation_tips);
1385                                 for_each_cached_alternate(&negotiator,
1386                                                           insert_one_alternate_object);
1387                         } else {
1388                                 filter_refs(args, &ref, sought, nr_sought);
1389                                 state = FETCH_SEND_REQUEST;
1390                         }
1391                         break;
1392                 case FETCH_SEND_REQUEST:
1393                         if (send_fetch_request(&negotiator, fd[1], args, ref,
1394                                                &common,
1395                                                &haves_to_send, &in_vain))
1396                                 state = FETCH_GET_PACK;
1397                         else
1398                                 state = FETCH_PROCESS_ACKS;
1399                         break;
1400                 case FETCH_PROCESS_ACKS:
1401                         /* Process ACKs/NAKs */
1402                         switch (process_acks(&negotiator, &reader, &common)) {
1403                         case 2:
1404                                 state = FETCH_GET_PACK;
1405                                 break;
1406                         case 1:
1407                                 in_vain = 0;
1408                                 /* fallthrough */
1409                         default:
1410                                 state = FETCH_SEND_REQUEST;
1411                                 break;
1412                         }
1413                         break;
1414                 case FETCH_GET_PACK:
1415                         /* Check for shallow-info section */
1416                         if (process_section_header(&reader, "shallow-info", 1))
1417                                 receive_shallow_info(args, &reader);
1418
1419                         if (process_section_header(&reader, "wanted-refs", 1))
1420                                 receive_wanted_refs(&reader, sought, nr_sought);
1421
1422                         /* get the pack */
1423                         process_section_header(&reader, "packfile", 0);
1424                         if (get_pack(args, fd, pack_lockfile))
1425                                 die(_("git fetch-pack: fetch failed."));
1426
1427                         state = FETCH_DONE;
1428                         break;
1429                 case FETCH_DONE:
1430                         continue;
1431                 }
1432         }
1433
1434         negotiator.release(&negotiator);
1435         oidset_clear(&common);
1436         return ref;
1437 }
1438
1439 static int fetch_pack_config_cb(const char *var, const char *value, void *cb)
1440 {
1441         if (strcmp(var, "fetch.fsck.skiplist") == 0) {
1442                 const char *path;
1443
1444                 if (git_config_pathname(&path, var, value))
1445                         return 1;
1446                 strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
1447                         fsck_msg_types.len ? ',' : '=', path);
1448                 free((char *)path);
1449                 return 0;
1450         }
1451
1452         if (skip_prefix(var, "fetch.fsck.", &var)) {
1453                 if (is_valid_msg_type(var, value))
1454                         strbuf_addf(&fsck_msg_types, "%c%s=%s",
1455                                 fsck_msg_types.len ? ',' : '=', var, value);
1456                 else
1457                         warning("Skipping unknown msg id '%s'", var);
1458                 return 0;
1459         }
1460
1461         return git_default_config(var, value, cb);
1462 }
1463
1464 static void fetch_pack_config(void)
1465 {
1466         git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
1467         git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
1468         git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
1469         git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
1470         git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
1471         git_config_get_string("fetch.negotiationalgorithm",
1472                               &negotiation_algorithm);
1473
1474         git_config(fetch_pack_config_cb, NULL);
1475 }
1476
1477 static void fetch_pack_setup(void)
1478 {
1479         static int did_setup;
1480         if (did_setup)
1481                 return;
1482         fetch_pack_config();
1483         if (0 <= transfer_unpack_limit)
1484                 unpack_limit = transfer_unpack_limit;
1485         else if (0 <= fetch_unpack_limit)
1486                 unpack_limit = fetch_unpack_limit;
1487         did_setup = 1;
1488 }
1489
1490 static int remove_duplicates_in_refs(struct ref **ref, int nr)
1491 {
1492         struct string_list names = STRING_LIST_INIT_NODUP;
1493         int src, dst;
1494
1495         for (src = dst = 0; src < nr; src++) {
1496                 struct string_list_item *item;
1497                 item = string_list_insert(&names, ref[src]->name);
1498                 if (item->util)
1499                         continue; /* already have it */
1500                 item->util = ref[src];
1501                 if (src != dst)
1502                         ref[dst] = ref[src];
1503                 dst++;
1504         }
1505         for (src = dst; src < nr; src++)
1506                 ref[src] = NULL;
1507         string_list_clear(&names, 0);
1508         return dst;
1509 }
1510
1511 static void update_shallow(struct fetch_pack_args *args,
1512                            struct ref **sought, int nr_sought,
1513                            struct shallow_info *si)
1514 {
1515         struct oid_array ref = OID_ARRAY_INIT;
1516         int *status;
1517         int i;
1518
1519         if (args->deepen && alternate_shallow_file) {
1520                 if (*alternate_shallow_file == '\0') { /* --unshallow */
1521                         unlink_or_warn(git_path_shallow(the_repository));
1522                         rollback_lock_file(&shallow_lock);
1523                 } else
1524                         commit_lock_file(&shallow_lock);
1525                 return;
1526         }
1527
1528         if (!si->shallow || !si->shallow->nr)
1529                 return;
1530
1531         if (args->cloning) {
1532                 /*
1533                  * remote is shallow, but this is a clone, there are
1534                  * no objects in repo to worry about. Accept any
1535                  * shallow points that exist in the pack (iow in repo
1536                  * after get_pack() and reprepare_packed_git())
1537                  */
1538                 struct oid_array extra = OID_ARRAY_INIT;
1539                 struct object_id *oid = si->shallow->oid;
1540                 for (i = 0; i < si->shallow->nr; i++)
1541                         if (has_object_file(&oid[i]))
1542                                 oid_array_append(&extra, &oid[i]);
1543                 if (extra.nr) {
1544                         setup_alternate_shallow(&shallow_lock,
1545                                                 &alternate_shallow_file,
1546                                                 &extra);
1547                         commit_lock_file(&shallow_lock);
1548                 }
1549                 oid_array_clear(&extra);
1550                 return;
1551         }
1552
1553         if (!si->nr_ours && !si->nr_theirs)
1554                 return;
1555
1556         remove_nonexistent_theirs_shallow(si);
1557         if (!si->nr_ours && !si->nr_theirs)
1558                 return;
1559         for (i = 0; i < nr_sought; i++)
1560                 oid_array_append(&ref, &sought[i]->old_oid);
1561         si->ref = &ref;
1562
1563         if (args->update_shallow) {
1564                 /*
1565                  * remote is also shallow, .git/shallow may be updated
1566                  * so all refs can be accepted. Make sure we only add
1567                  * shallow roots that are actually reachable from new
1568                  * refs.
1569                  */
1570                 struct oid_array extra = OID_ARRAY_INIT;
1571                 struct object_id *oid = si->shallow->oid;
1572                 assign_shallow_commits_to_refs(si, NULL, NULL);
1573                 if (!si->nr_ours && !si->nr_theirs) {
1574                         oid_array_clear(&ref);
1575                         return;
1576                 }
1577                 for (i = 0; i < si->nr_ours; i++)
1578                         oid_array_append(&extra, &oid[si->ours[i]]);
1579                 for (i = 0; i < si->nr_theirs; i++)
1580                         oid_array_append(&extra, &oid[si->theirs[i]]);
1581                 setup_alternate_shallow(&shallow_lock,
1582                                         &alternate_shallow_file,
1583                                         &extra);
1584                 commit_lock_file(&shallow_lock);
1585                 oid_array_clear(&extra);
1586                 oid_array_clear(&ref);
1587                 return;
1588         }
1589
1590         /*
1591          * remote is also shallow, check what ref is safe to update
1592          * without updating .git/shallow
1593          */
1594         status = xcalloc(nr_sought, sizeof(*status));
1595         assign_shallow_commits_to_refs(si, NULL, status);
1596         if (si->nr_ours || si->nr_theirs) {
1597                 for (i = 0; i < nr_sought; i++)
1598                         if (status[i])
1599                                 sought[i]->status = REF_STATUS_REJECT_SHALLOW;
1600         }
1601         free(status);
1602         oid_array_clear(&ref);
1603 }
1604
1605 static int iterate_ref_map(void *cb_data, struct object_id *oid)
1606 {
1607         struct ref **rm = cb_data;
1608         struct ref *ref = *rm;
1609
1610         if (!ref)
1611                 return -1; /* end of the list */
1612         *rm = ref->next;
1613         oidcpy(oid, &ref->old_oid);
1614         return 0;
1615 }
1616
1617 struct ref *fetch_pack(struct fetch_pack_args *args,
1618                        int fd[], struct child_process *conn,
1619                        const struct ref *ref,
1620                        const char *dest,
1621                        struct ref **sought, int nr_sought,
1622                        struct oid_array *shallow,
1623                        char **pack_lockfile,
1624                        enum protocol_version version)
1625 {
1626         struct ref *ref_cpy;
1627         struct shallow_info si;
1628
1629         fetch_pack_setup();
1630         if (nr_sought)
1631                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
1632
1633         if (args->no_dependents && !args->filter_options.choice) {
1634                 /*
1635                  * The protocol does not support requesting that only the
1636                  * wanted objects be sent, so approximate this by setting a
1637                  * "blob:none" filter if no filter is already set. This works
1638                  * for all object types: note that wanted blobs will still be
1639                  * sent because they are directly specified as a "want".
1640                  *
1641                  * NEEDSWORK: Add an option in the protocol to request that
1642                  * only the wanted objects be sent, and implement it.
1643                  */
1644                 parse_list_objects_filter(&args->filter_options, "blob:none");
1645         }
1646
1647         if (version != protocol_v2 && !ref) {
1648                 packet_flush(fd[1]);
1649                 die(_("no matching remote head"));
1650         }
1651         prepare_shallow_info(&si, shallow);
1652         if (version == protocol_v2)
1653                 ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
1654                                            pack_lockfile);
1655         else
1656                 ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
1657                                         &si, pack_lockfile);
1658         reprepare_packed_git(the_repository);
1659
1660         if (!args->cloning && args->deepen) {
1661                 struct check_connected_options opt = CHECK_CONNECTED_INIT;
1662                 struct ref *iterator = ref_cpy;
1663                 opt.shallow_file = alternate_shallow_file;
1664                 if (args->deepen)
1665                         opt.is_deepening_fetch = 1;
1666                 if (check_connected(iterate_ref_map, &iterator, &opt)) {
1667                         error(_("remote did not send all necessary objects"));
1668                         free_refs(ref_cpy);
1669                         ref_cpy = NULL;
1670                         rollback_lock_file(&shallow_lock);
1671                         goto cleanup;
1672                 }
1673                 args->connectivity_checked = 1;
1674         }
1675
1676         update_shallow(args, sought, nr_sought, &si);
1677 cleanup:
1678         clear_shallow_info(&si);
1679         return ref_cpy;
1680 }
1681
1682 int report_unmatched_refs(struct ref **sought, int nr_sought)
1683 {
1684         int i, ret = 0;
1685
1686         for (i = 0; i < nr_sought; i++) {
1687                 if (!sought[i])
1688                         continue;
1689                 switch (sought[i]->match_status) {
1690                 case REF_MATCHED:
1691                         continue;
1692                 case REF_NOT_MATCHED:
1693                         error(_("no such remote ref %s"), sought[i]->name);
1694                         break;
1695                 case REF_UNADVERTISED_NOT_ALLOWED:
1696                         error(_("Server does not allow request for unadvertised object %s"),
1697                               sought[i]->name);
1698                         break;
1699                 }
1700                 ret = 1;
1701         }
1702         return ret;
1703 }