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                 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->hash)) != 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                 struct strbuf expanded_filter_spec = STRBUF_INIT;
 343                 expand_list_objects_filter_spec(&args->filter_options,
 344                                                 &expanded_filter_spec);
 345                 packet_buf_write(&req_buf, "filter %s",
 346                                  expanded_filter_spec.buf);
 347                 strbuf_release(&expanded_filter_spec);
 348         }
 349         packet_buf_flush(&req_buf);
 350         state_len = req_buf.len;
 351
 352         if (args->deepen) {
 353                 const char *arg;
 354                 struct object_id oid;
 355
 356                 send_request(args, fd[1], &req_buf);
 357                 while (packet_reader_read(&reader) == PACKET_READ_NORMAL) {
 358                         if (skip_prefix(reader.line, "shallow ", &arg)) {
 359                                 if (get_oid_hex(arg, &oid))
 360                                         die(_("invalid shallow line: %s"), reader.line);
 361                                 register_shallow(the_repository, &oid);
 362                                 continue;
 363                         }
 364                         if (skip_prefix(reader.line, "unshallow ", &arg)) {
 365                                 if (get_oid_hex(arg, &oid))
 366                                         die(_("invalid unshallow line: %s"), reader.line);
 367                                 if (!lookup_object(the_repository, oid.hash))
 368                                         die(_("object not found: %s"), reader.line);
 369                                 /* make sure that it is parsed as shallow */
 370                                 if (!parse_object(the_repository, &oid))
 371                                         die(_("error in object: %s"), reader.line);
 372                                 if (unregister_shallow(&oid))
 373                                         die(_("no shallow found: %s"), reader.line);
 374                                 continue;
 375                         }
 376                         die(_("expected shallow/unshallow, got %s"), reader.line);
 377                 }
 378         } else if (!args->stateless_rpc)
 379                 send_request(args, fd[1], &req_buf);
 380
 381         if (!args->stateless_rpc) {
 382                 /* If we aren't using the stateless-rpc interface
 383                  * we don't need to retain the headers.
 384                  */
 385                 strbuf_setlen(&req_buf, 0);
 386                 state_len = 0;
 387         }
 388
 389         flushes = 0;
 390         retval = -1;
 391         if (args->no_dependents)
 392                 goto done;
 393         while ((oid = negotiator->next(negotiator))) {
 394                 packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid));
 395                 print_verbose(args, "have %s", oid_to_hex(oid));
 396                 in_vain++;
 397                 if (flush_at <= ++count) {
 398                         int ack;
 399
 400                         packet_buf_flush(&req_buf);
 401                         send_request(args, fd[1], &req_buf);
 402                         strbuf_setlen(&req_buf, state_len);
 403                         flushes++;
 404                         flush_at = next_flush(args->stateless_rpc, count);
 405
 406                         /*
 407                          * We keep one window "ahead" of the other side, and
 408                          * will wait for an ACK only on the next one
 409                          */
 410                         if (!args->stateless_rpc && count == INITIAL_FLUSH)
 411                                 continue;
 412
 413                         consume_shallow_list(args, &reader);
 414                         do {
 415                                 ack = get_ack(&reader, result_oid);
 416                                 if (ack)
 417                                         print_verbose(args, _("got %s %d %s"), "ack",
 418                                                       ack, oid_to_hex(result_oid));
 419                                 switch (ack) {
 420                                 case ACK:
 421                                         flushes = 0;
 422                                         multi_ack = 0;
 423                                         retval = 0;
 424                                         goto done;
 425                                 case ACK_common:
 426                                 case ACK_ready:
 427                                 case ACK_continue: {
 428                                         struct commit *commit =
 429                                                 lookup_commit(the_repository,
 430                                                               result_oid);
 431                                         int was_common;
 432
 433                                         if (!commit)
 434                                                 die(_("invalid commit %s"), oid_to_hex(result_oid));
 435                                         was_common = negotiator->ack(negotiator, commit);
 436                                         if (args->stateless_rpc
 437                                          && ack == ACK_common
 438                                          && !was_common) {
 439                                                 /* We need to replay the have for this object
 440                                                  * on the next RPC request so the peer knows
 441                                                  * it is in common with us.
 442                                                  */
 443                                                 const char *hex = oid_to_hex(result_oid);
 444                                                 packet_buf_write(&req_buf, "have %s\n", hex);
 445                                                 state_len = req_buf.len;
 446                                                 /*
 447                                                  * Reset in_vain because an ack
 448                                                  * for this commit has not been
 449                                                  * seen.
 450                                                  */
 451                                                 in_vain = 0;
 452                                         } else if (!args->stateless_rpc
 453                                                    || ack != ACK_common)
 454                                                 in_vain = 0;
 455                                         retval = 0;
 456                                         got_continue = 1;
 457                                         if (ack == ACK_ready)
 458                                                 got_ready = 1;
 459                                         break;
 460                                         }
 461                                 }
 462                         } while (ack);
 463                         flushes--;
 464                         if (got_continue && MAX_IN_VAIN < in_vain) {
 465                                 print_verbose(args, _("giving up"));
 466                                 break; /* give up */
 467                         }
 468                         if (got_ready)
 469                                 break;
 470                 }
 471         }
 472 done:
 473         if (!got_ready || !no_done) {
 474                 packet_buf_write(&req_buf, "done\n");
 475                 send_request(args, fd[1], &req_buf);
 476         }
 477         print_verbose(args, _("done"));
 478         if (retval != 0) {
 479                 multi_ack = 0;
 480                 flushes++;
 481         }
 482         strbuf_release(&req_buf);
 483
 484         if (!got_ready || !no_done)
 485                 consume_shallow_list(args, &reader);
 486         while (flushes || multi_ack) {
 487                 int ack = get_ack(&reader, result_oid);
 488                 if (ack) {
 489                         print_verbose(args, _("got %s (%d) %s"), "ack",
 490                                       ack, oid_to_hex(result_oid));
 491                         if (ack == ACK)
 492                                 return 0;
 493                         multi_ack = 1;
 494                         continue;
 495                 }
 496                 flushes--;
 497         }
 498         /* it is no error to fetch into a completely empty repo */
 499         return count ? retval : 0;
 500 }
 501
 502 static struct commit_list *complete;
 503
 504 static int mark_complete(const struct object_id *oid)
 505 {
 506         struct object *o = parse_object(the_repository, oid);
 507
 508         while (o && o->type == OBJ_TAG) {
 509                 struct tag *t = (struct tag *) o;
 510                 if (!t->tagged)
 511                         break; /* broken repository */
 512                 o->flags |= COMPLETE;
 513                 o = parse_object(the_repository, &t->tagged->oid);
 514         }
 515         if (o && o->type == OBJ_COMMIT) {
 516                 struct commit *commit = (struct commit *)o;
 517                 if (!(commit->object.flags & COMPLETE)) {
 518                         commit->object.flags |= COMPLETE;
 519                         commit_list_insert(commit, &complete);
 520                 }
 521         }
 522         return 0;
 523 }
 524
 525 static int mark_complete_oid(const char *refname, const struct object_id *oid,
 526                              int flag, void *cb_data)
 527 {
 528         return mark_complete(oid);
 529 }
 530
 531 static void mark_recent_complete_commits(struct fetch_pack_args *args,
 532                                          timestamp_t cutoff)
 533 {
 534         while (complete && cutoff <= complete->item->date) {
 535                 print_verbose(args, _("Marking %s as complete"),
 536                               oid_to_hex(&complete->item->object.oid));
 537                 pop_most_recent_commit(&complete, COMPLETE);
 538         }
 539 }
 540
 541 static void add_refs_to_oidset(struct oidset *oids, struct ref *refs)
 542 {
 543         for (; refs; refs = refs->next)
 544                 oidset_insert(oids, &refs->old_oid);
 545 }
 546
 547 static int is_unmatched_ref(const struct ref *ref)
 548 {
 549         struct object_id oid;
 550         const char *p;
 551         return  ref->match_status == REF_NOT_MATCHED &&
 552                 !parse_oid_hex(ref->name, &oid, &p) &&
 553                 *p == '\0' &&
 554                 oideq(&oid, &ref->old_oid);
 555 }
 556
 557 static void filter_refs(struct fetch_pack_args *args,
 558                         struct ref **refs,
 559                         struct ref **sought, int nr_sought)
 560 {
 561         struct ref *newlist = NULL;
 562         struct ref **newtail = &newlist;
 563         struct ref *unmatched = NULL;
 564         struct ref *ref, *next;
 565         struct oidset tip_oids = OIDSET_INIT;
 566         int i;
 567         int strict = !(allow_unadvertised_object_request &
 568                        (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1));
 569
 570         i = 0;
 571         for (ref = *refs; ref; ref = next) {
 572                 int keep = 0;
 573                 next = ref->next;
 574
 575                 if (starts_with(ref->name, "refs/") &&
 576                     check_refname_format(ref->name, 0)) {
 577                         /*
 578                          * trash or a peeled value; do not even add it to
 579                          * unmatched list
 580                          */
 581                         free_one_ref(ref);
 582                         continue;
 583                 } else {
 584                         while (i < nr_sought) {
 585                                 int cmp = strcmp(ref->name, sought[i]->name);
 586                                 if (cmp < 0)
 587                                         break; /* definitely do not have it */
 588                                 else if (cmp == 0) {
 589                                         keep = 1; /* definitely have it */
 590                                         sought[i]->match_status = REF_MATCHED;
 591                                 }
 592                                 i++;
 593                         }
 594
 595                         if (!keep && args->fetch_all &&
 596                             (!args->deepen || !starts_with(ref->name, "refs/tags/")))
 597                                 keep = 1;
 598                 }
 599
 600                 if (keep) {
 601                         *newtail = ref;
 602                         ref->next = NULL;
 603                         newtail = &ref->next;
 604                 } else {
 605                         ref->next = unmatched;
 606                         unmatched = ref;
 607                 }
 608         }
 609
 610         if (strict) {
 611                 for (i = 0; i < nr_sought; i++) {
 612                         ref = sought[i];
 613                         if (!is_unmatched_ref(ref))
 614                                 continue;
 615
 616                         add_refs_to_oidset(&tip_oids, unmatched);
 617                         add_refs_to_oidset(&tip_oids, newlist);
 618                         break;
 619                 }
 620         }
 621
 622         /* Append unmatched requests to the list */
 623         for (i = 0; i < nr_sought; i++) {
 624                 ref = sought[i];
 625                 if (!is_unmatched_ref(ref))
 626                         continue;
 627
 628                 if (!strict || oidset_contains(&tip_oids, &ref->old_oid)) {
 629                         ref->match_status = REF_MATCHED;
 630                         *newtail = copy_ref(ref);
 631                         newtail = &(*newtail)->next;
 632                 } else {
 633                         ref->match_status = REF_UNADVERTISED_NOT_ALLOWED;
 634                 }
 635         }
 636
 637         oidset_clear(&tip_oids);
 638         free_refs(unmatched);
 639
 640         *refs = newlist;
 641 }
 642
 643 static void mark_alternate_complete(struct fetch_negotiator *unused,
 644                                     struct object *obj)
 645 {
 646         mark_complete(&obj->oid);
 647 }
 648
 649 struct loose_object_iter {
 650         struct oidset *loose_object_set;
 651         struct ref *refs;
 652 };
 653
 654 /*
 655  * Mark recent commits available locally and reachable from a local ref as
 656  * COMPLETE. If args->no_dependents is false, also mark COMPLETE remote refs as
 657  * COMMON_REF (otherwise, we are not planning to participate in negotiation, and
 658  * thus do not need COMMON_REF marks).
 659  *
 660  * The cutoff time for recency is determined by this heuristic: it is the
 661  * earliest commit time of the objects in refs that are commits and that we know
 662  * the commit time of.
 663  */
 664 static void mark_complete_and_common_ref(struct fetch_negotiator *negotiator,
 665                                          struct fetch_pack_args *args,
 666                                          struct ref **refs)
 667 {
 668         struct ref *ref;
 669         int old_save_commit_buffer = save_commit_buffer;
 670         timestamp_t cutoff = 0;
 671
 672         save_commit_buffer = 0;
 673
 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                         continue;
 680                 o = parse_object(the_repository, &ref->old_oid);
 681                 if (!o)
 682                         continue;
 683
 684                 /* We already have it -- which may mean that we were
 685                  * in sync with the other side at some time after
 686                  * that (it is OK if we guess wrong here).
 687                  */
 688                 if (o->type == OBJ_COMMIT) {
 689                         struct commit *commit = (struct commit *)o;
 690                         if (!cutoff || cutoff < commit->date)
 691                                 cutoff = commit->date;
 692                 }
 693         }
 694
 695         if (!args->deepen) {
 696                 for_each_ref(mark_complete_oid, NULL);
 697                 for_each_cached_alternate(NULL, mark_alternate_complete);
 698                 commit_list_sort_by_date(&complete);
 699                 if (cutoff)
 700                         mark_recent_complete_commits(args, cutoff);
 701         }
 702
 703         /*
 704          * Mark all complete remote refs as common refs.
 705          * Don't mark them common yet; the server has to be told so first.
 706          */
 707         for (ref = *refs; ref; ref = ref->next) {
 708                 struct object *o = deref_tag(the_repository,
 709                                              lookup_object(the_repository,
 710                                              ref->old_oid.hash),
 711                                              NULL, 0);
 712
 713                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
 714                         continue;
 715
 716                 negotiator->known_common(negotiator,
 717                                          (struct commit *)o);
 718         }
 719
 720         save_commit_buffer = old_save_commit_buffer;
 721 }
 722
 723 /*
 724  * Returns 1 if every object pointed to by the given remote refs is available
 725  * locally and reachable from a local ref, and 0 otherwise.
 726  */
 727 static int everything_local(struct fetch_pack_args *args,
 728                             struct ref **refs)
 729 {
 730         struct ref *ref;
 731         int retval;
 732
 733         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
 734                 const struct object_id *remote = &ref->old_oid;
 735                 struct object *o;
 736
 737                 o = lookup_object(the_repository, remote->hash);
 738                 if (!o || !(o->flags & COMPLETE)) {
 739                         retval = 0;
 740                         print_verbose(args, "want %s (%s)", oid_to_hex(remote),
 741                                       ref->name);
 742                         continue;
 743                 }
 744                 print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
 745                               ref->name);
 746         }
 747
 748         return retval;
 749 }
 750
 751 static int sideband_demux(int in, int out, void *data)
 752 {
 753         int *xd = data;
 754         int ret;
 755
 756         ret = recv_sideband("fetch-pack", xd[0], out);
 757         close(out);
 758         return ret;
 759 }
 760
 761 static int get_pack(struct fetch_pack_args *args,
 762                     int xd[2], char **pack_lockfile)
 763 {
 764         struct async demux;
 765         int do_keep = args->keep_pack;
 766         const char *cmd_name;
 767         struct pack_header header;
 768         int pass_header = 0;
 769         struct child_process cmd = CHILD_PROCESS_INIT;
 770         int ret;
 771
 772         memset(&demux, 0, sizeof(demux));
 773         if (use_sideband) {
 774                 /* xd[] is talking with upload-pack; subprocess reads from
 775                  * xd[0], spits out band#2 to stderr, and feeds us band#1
 776                  * through demux->out.
 777                  */
 778                 demux.proc = sideband_demux;
 779                 demux.data = xd;
 780                 demux.out = -1;
 781                 demux.isolate_sigpipe = 1;
 782                 if (start_async(&demux))
 783                         die(_("fetch-pack: unable to fork off sideband demultiplexer"));
 784         }
 785         else
 786                 demux.out = xd[0];
 787
 788         if (!args->keep_pack && unpack_limit) {
 789
 790                 if (read_pack_header(demux.out, &header))
 791                         die(_("protocol error: bad pack header"));
 792                 pass_header = 1;
 793                 if (ntohl(header.hdr_entries) < unpack_limit)
 794                         do_keep = 0;
 795                 else
 796                         do_keep = 1;
 797         }
 798
 799         if (alternate_shallow_file) {
 800                 argv_array_push(&cmd.args, "--shallow-file");
 801                 argv_array_push(&cmd.args, alternate_shallow_file);
 802         }
 803
 804         if (do_keep || args->from_promisor) {
 805                 if (pack_lockfile)
 806                         cmd.out = -1;
 807                 cmd_name = "index-pack";
 808                 argv_array_push(&cmd.args, cmd_name);
 809                 argv_array_push(&cmd.args, "--stdin");
 810                 if (!args->quiet && !args->no_progress)
 811                         argv_array_push(&cmd.args, "-v");
 812                 if (args->use_thin_pack)
 813                         argv_array_push(&cmd.args, "--fix-thin");
 814                 if (do_keep && (args->lock_pack || unpack_limit)) {
 815                         char hostname[HOST_NAME_MAX + 1];
 816                         if (xgethostname(hostname, sizeof(hostname)))
 817                                 xsnprintf(hostname, sizeof(hostname), "localhost");
 818                         argv_array_pushf(&cmd.args,
 819                                         "--keep=fetch-pack %"PRIuMAX " on %s",
 820                                         (uintmax_t)getpid(), hostname);
 821                 }
 822                 if (args->check_self_contained_and_connected)
 823                         argv_array_push(&cmd.args, "--check-self-contained-and-connected");
 824                 if (args->from_promisor)
 825                         argv_array_push(&cmd.args, "--promisor");
 826         }
 827         else {
 828                 cmd_name = "unpack-objects";
 829                 argv_array_push(&cmd.args, cmd_name);
 830                 if (args->quiet || args->no_progress)
 831                         argv_array_push(&cmd.args, "-q");
 832                 args->check_self_contained_and_connected = 0;
 833         }
 834
 835         if (pass_header)
 836                 argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
 837                                  ntohl(header.hdr_version),
 838                                  ntohl(header.hdr_entries));
 839         if (fetch_fsck_objects >= 0
 840             ? fetch_fsck_objects
 841             : transfer_fsck_objects >= 0
 842             ? transfer_fsck_objects
 843             : 0) {
 844                 if (args->from_promisor)
 845                         /*
 846                          * We cannot use --strict in index-pack because it
 847                          * checks both broken objects and links, but we only
 848                          * want to check for broken objects.
 849                          */
 850                         argv_array_push(&cmd.args, "--fsck-objects");
 851                 else
 852                         argv_array_pushf(&cmd.args, "--strict%s",
 853                                          fsck_msg_types.buf);
 854         }
 855
 856         cmd.in = demux.out;
 857         cmd.git_cmd = 1;
 858         if (start_command(&cmd))
 859                 die(_("fetch-pack: unable to fork off %s"), cmd_name);
 860         if (do_keep && pack_lockfile) {
 861                 *pack_lockfile = index_pack_lockfile(cmd.out);
 862                 close(cmd.out);
 863         }
 864
 865         if (!use_sideband)
 866                 /* Closed by start_command() */
 867                 xd[0] = -1;
 868
 869         ret = finish_command(&cmd);
 870         if (!ret || (args->check_self_contained_and_connected && ret == 1))
 871                 args->self_contained_and_connected =
 872                         args->check_self_contained_and_connected &&
 873                         ret == 0;
 874         else
 875                 die(_("%s failed"), cmd_name);
 876         if (use_sideband && finish_async(&demux))
 877                 die(_("error in sideband demultiplexer"));
 878         return 0;
 879 }
 880
 881 static int cmp_ref_by_name(const void *a_, const void *b_)
 882 {
 883         const struct ref *a = *((const struct ref **)a_);
 884         const struct ref *b = *((const struct ref **)b_);
 885         return strcmp(a->name, b->name);
 886 }
 887
 888 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 889                                  int fd[2],
 890                                  const struct ref *orig_ref,
 891                                  struct ref **sought, int nr_sought,
 892                                  struct shallow_info *si,
 893                                  char **pack_lockfile)
 894 {
 895         struct ref *ref = copy_ref_list(orig_ref);
 896         struct object_id oid;
 897         const char *agent_feature;
 898         int agent_len;
 899         struct fetch_negotiator negotiator;
 900         fetch_negotiator_init(&negotiator, negotiation_algorithm);
 901
 902         sort_ref_list(&ref, ref_compare_name);
 903         QSORT(sought, nr_sought, cmp_ref_by_name);
 904
 905         if ((args->depth > 0 || is_repository_shallow(the_repository)) && !server_supports("shallow"))
 906                 die(_("Server does not support shallow clients"));
 907         if (args->depth > 0 || args->deepen_since || args->deepen_not)
 908                 args->deepen = 1;
 909         if (server_supports("multi_ack_detailed")) {
 910                 print_verbose(args, _("Server supports multi_ack_detailed"));
 911                 multi_ack = 2;
 912                 if (server_supports("no-done")) {
 913                         print_verbose(args, _("Server supports no-done"));
 914                         if (args->stateless_rpc)
 915                                 no_done = 1;
 916                 }
 917         }
 918         else if (server_supports("multi_ack")) {
 919                 print_verbose(args, _("Server supports multi_ack"));
 920                 multi_ack = 1;
 921         }
 922         if (server_supports("side-band-64k")) {
 923                 print_verbose(args, _("Server supports side-band-64k"));
 924                 use_sideband = 2;
 925         }
 926         else if (server_supports("side-band")) {
 927                 print_verbose(args, _("Server supports side-band"));
 928                 use_sideband = 1;
 929         }
 930         if (server_supports("allow-tip-sha1-in-want")) {
 931                 print_verbose(args, _("Server supports allow-tip-sha1-in-want"));
 932                 allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
 933         }
 934         if (server_supports("allow-reachable-sha1-in-want")) {
 935                 print_verbose(args, _("Server supports allow-reachable-sha1-in-want"));
 936                 allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
 937         }
 938         if (!server_supports("thin-pack"))
 939                 args->use_thin_pack = 0;
 940         if (!server_supports("no-progress"))
 941                 args->no_progress = 0;
 942         if (!server_supports("include-tag"))
 943                 args->include_tag = 0;
 944         if (server_supports("ofs-delta"))
 945                 print_verbose(args, _("Server supports ofs-delta"));
 946         else
 947                 prefer_ofs_delta = 0;
 948
 949         if (server_supports("filter")) {
 950                 server_supports_filtering = 1;
 951                 print_verbose(args, _("Server supports filter"));
 952         } else if (args->filter_options.choice) {
 953                 warning("filtering not recognized by server, ignoring");
 954         }
 955
 956         if ((agent_feature = server_feature_value("agent", &agent_len))) {
 957                 agent_supported = 1;
 958                 if (agent_len)
 959                         print_verbose(args, _("Server version is %.*s"),
 960                                       agent_len, agent_feature);
 961         }
 962         if (server_supports("deepen-since"))
 963                 deepen_since_ok = 1;
 964         else if (args->deepen_since)
 965                 die(_("Server does not support --shallow-since"));
 966         if (server_supports("deepen-not"))
 967                 deepen_not_ok = 1;
 968         else if (args->deepen_not)
 969                 die(_("Server does not support --shallow-exclude"));
 970         if (!server_supports("deepen-relative") && args->deepen_relative)
 971                 die(_("Server does not support --deepen"));
 972
 973         if (!args->no_dependents) {
 974                 mark_complete_and_common_ref(&negotiator, args, &ref);
 975                 filter_refs(args, &ref, sought, nr_sought);
 976                 if (everything_local(args, &ref)) {
 977                         packet_flush(fd[1]);
 978                         goto all_done;
 979                 }
 980         } else {
 981                 filter_refs(args, &ref, sought, nr_sought);
 982         }
 983         if (find_common(&negotiator, args, fd, &oid, ref) < 0)
 984                 if (!args->keep_pack)
 985                         /* When cloning, it is not unusual to have
 986                          * no common commit.
 987                          */
 988                         warning(_("no common commits"));
 989
 990         if (args->stateless_rpc)
 991                 packet_flush(fd[1]);
 992         if (args->deepen)
 993                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
 994                                         NULL);
 995         else if (si->nr_ours || si->nr_theirs)
 996                 alternate_shallow_file = setup_temporary_shallow(si->shallow);
 997         else
 998                 alternate_shallow_file = NULL;
 999         if (get_pack(args, fd, pack_lockfile))
1000                 die(_("git fetch-pack: fetch failed."));
1001
1002  all_done:
1003         negotiator.release(&negotiator);
1004         return ref;
1005 }
1006
1007 static void add_shallow_requests(struct strbuf *req_buf,
1008                                  const struct fetch_pack_args *args)
1009 {
1010         if (is_repository_shallow(the_repository))
1011                 write_shallow_commits(req_buf, 1, NULL);
1012         if (args->depth > 0)
1013                 packet_buf_write(req_buf, "deepen %d", args->depth);
1014         if (args->deepen_since) {
1015                 timestamp_t max_age = approxidate(args->deepen_since);
1016                 packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
1017         }
1018         if (args->deepen_not) {
1019                 int i;
1020                 for (i = 0; i < args->deepen_not->nr; i++) {
1021                         struct string_list_item *s = args->deepen_not->items + i;
1022                         packet_buf_write(req_buf, "deepen-not %s", s->string);
1023                 }
1024         }
1025         if (args->deepen_relative)
1026                 packet_buf_write(req_buf, "deepen-relative\n");
1027 }
1028
1029 static void add_wants(int no_dependents, const struct ref *wants, struct strbuf *req_buf)
1030 {
1031         int use_ref_in_want = server_supports_feature("fetch", "ref-in-want", 0);
1032
1033         for ( ; wants ; wants = wants->next) {
1034                 const struct object_id *remote = &wants->old_oid;
1035                 struct object *o;
1036
1037                 /*
1038                  * If that object is complete (i.e. it is an ancestor of a
1039                  * local ref), we tell them we have it but do not have to
1040                  * tell them about its ancestors, which they already know
1041                  * about.
1042                  *
1043                  * We use lookup_object here because we are only
1044                  * interested in the case we *know* the object is
1045                  * reachable and we have already scanned it.
1046                  *
1047                  * Do this only if args->no_dependents is false (if it is true,
1048                  * we cannot trust the object flags).
1049                  */
1050                 if (!no_dependents &&
1051                     ((o = lookup_object(the_repository, remote->hash)) != NULL) &&
1052                     (o->flags & COMPLETE)) {
1053                         continue;
1054                 }
1055
1056                 if (!use_ref_in_want || wants->exact_oid)
1057                         packet_buf_write(req_buf, "want %s\n", oid_to_hex(remote));
1058                 else
1059                         packet_buf_write(req_buf, "want-ref %s\n", wants->name);
1060         }
1061 }
1062
1063 static void add_common(struct strbuf *req_buf, struct oidset *common)
1064 {
1065         struct oidset_iter iter;
1066         const struct object_id *oid;
1067         oidset_iter_init(common, &iter);
1068
1069         while ((oid = oidset_iter_next(&iter))) {
1070                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1071         }
1072 }
1073
1074 static int add_haves(struct fetch_negotiator *negotiator,
1075                      struct strbuf *req_buf,
1076                      int *haves_to_send, int *in_vain)
1077 {
1078         int ret = 0;
1079         int haves_added = 0;
1080         const struct object_id *oid;
1081
1082         while ((oid = negotiator->next(negotiator))) {
1083                 packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
1084                 if (++haves_added >= *haves_to_send)
1085                         break;
1086         }
1087
1088         *in_vain += haves_added;
1089         if (!haves_added || *in_vain >= MAX_IN_VAIN) {
1090                 /* Send Done */
1091                 packet_buf_write(req_buf, "done\n");
1092                 ret = 1;
1093         }
1094
1095         /* Increase haves to send on next round */
1096         *haves_to_send = next_flush(1, *haves_to_send);
1097
1098         return ret;
1099 }
1100
1101 static int send_fetch_request(struct fetch_negotiator *negotiator, int fd_out,
1102                               const struct fetch_pack_args *args,
1103                               const struct ref *wants, struct oidset *common,
1104                               int *haves_to_send, int *in_vain,
1105                               int sideband_all)
1106 {
1107         int ret = 0;
1108         struct strbuf req_buf = STRBUF_INIT;
1109
1110         if (server_supports_v2("fetch", 1))
1111                 packet_buf_write(&req_buf, "command=fetch");
1112         if (server_supports_v2("agent", 0))
1113                 packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
1114         if (args->server_options && args->server_options->nr &&
1115             server_supports_v2("server-option", 1)) {
1116                 int i;
1117                 for (i = 0; i < args->server_options->nr; i++)
1118                         packet_write_fmt(fd_out, "server-option=%s",
1119                                          args->server_options->items[i].string);
1120         }
1121
1122         packet_buf_delim(&req_buf);
1123         if (args->use_thin_pack)
1124                 packet_buf_write(&req_buf, "thin-pack");
1125         if (args->no_progress)
1126                 packet_buf_write(&req_buf, "no-progress");
1127         if (args->include_tag)
1128                 packet_buf_write(&req_buf, "include-tag");
1129         if (prefer_ofs_delta)
1130                 packet_buf_write(&req_buf, "ofs-delta");
1131         if (sideband_all)
1132                 packet_buf_write(&req_buf, "sideband-all");
1133
1134         /* Add shallow-info and deepen request */
1135         if (server_supports_feature("fetch", "shallow", 0))
1136                 add_shallow_requests(&req_buf, args);
1137         else if (is_repository_shallow(the_repository) || args->deepen)
1138                 die(_("Server does not support shallow requests"));
1139
1140         /* Add filter */
1141         if (server_supports_feature("fetch", "filter", 0) &&
1142             args->filter_options.choice) {
1143                 struct strbuf expanded_filter_spec = STRBUF_INIT;
1144                 print_verbose(args, _("Server supports filter"));
1145                 expand_list_objects_filter_spec(&args->filter_options,
1146                                                 &expanded_filter_spec);
1147                 packet_buf_write(&req_buf, "filter %s",
1148                                  expanded_filter_spec.buf);
1149                 strbuf_release(&expanded_filter_spec);
1150         } else if (args->filter_options.choice) {
1151                 warning("filtering not recognized by server, ignoring");
1152         }
1153
1154         /* add wants */
1155         add_wants(args->no_dependents, wants, &req_buf);
1156
1157         if (args->no_dependents) {
1158                 packet_buf_write(&req_buf, "done");
1159                 ret = 1;
1160         } else {
1161                 /* Add all of the common commits we've found in previous rounds */
1162                 add_common(&req_buf, common);
1163
1164                 /* Add initial haves */
1165                 ret = add_haves(negotiator, &req_buf, haves_to_send, in_vain);
1166         }
1167
1168         /* Send request */
1169         packet_buf_flush(&req_buf);
1170         if (write_in_full(fd_out, req_buf.buf, req_buf.len) < 0)
1171                 die_errno(_("unable to write request to remote"));
1172
1173         strbuf_release(&req_buf);
1174         return ret;
1175 }
1176
1177 /*
1178  * Processes a section header in a server's response and checks if it matches
1179  * `section`.  If the value of `peek` is 1, the header line will be peeked (and
1180  * not consumed); if 0, the line will be consumed and the function will die if
1181  * the section header doesn't match what was expected.
1182  */
1183 static int process_section_header(struct packet_reader *reader,
1184                                   const char *section, int peek)
1185 {
1186         int ret;
1187
1188         if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
1189                 die(_("error reading section header '%s'"), section);
1190
1191         ret = !strcmp(reader->line, section);
1192
1193         if (!peek) {
1194                 if (!ret)
1195                         die(_("expected '%s', received '%s'"),
1196                             section, reader->line);
1197                 packet_reader_read(reader);
1198         }
1199
1200         return ret;
1201 }
1202
1203 static int process_acks(struct fetch_negotiator *negotiator,
1204                         struct packet_reader *reader,
1205                         struct oidset *common)
1206 {
1207         /* received */
1208         int received_ready = 0;
1209         int received_ack = 0;
1210
1211         process_section_header(reader, "acknowledgments", 0);
1212         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1213                 const char *arg;
1214
1215                 if (!strcmp(reader->line, "NAK"))
1216                         continue;
1217
1218                 if (skip_prefix(reader->line, "ACK ", &arg)) {
1219                         struct object_id oid;
1220                         if (!get_oid_hex(arg, &oid)) {
1221                                 struct commit *commit;
1222                                 oidset_insert(common, &oid);
1223                                 commit = lookup_commit(the_repository, &oid);
1224                                 negotiator->ack(negotiator, commit);
1225                         }
1226                         continue;
1227                 }
1228
1229                 if (!strcmp(reader->line, "ready")) {
1230                         received_ready = 1;
1231                         continue;
1232                 }
1233
1234                 die(_("unexpected acknowledgment line: '%s'"), reader->line);
1235         }
1236
1237         if (reader->status != PACKET_READ_FLUSH &&
1238             reader->status != PACKET_READ_DELIM)
1239                 die(_("error processing acks: %d"), reader->status);
1240
1241         /*
1242          * If an "acknowledgments" section is sent, a packfile is sent if and
1243          * only if "ready" was sent in this section. The other sections
1244          * ("shallow-info" and "wanted-refs") are sent only if a packfile is
1245          * sent. Therefore, a DELIM is expected if "ready" is sent, and a FLUSH
1246          * otherwise.
1247          */
1248         if (received_ready && reader->status != PACKET_READ_DELIM)
1249                 die(_("expected packfile to be sent after 'ready'"));
1250         if (!received_ready && reader->status != PACKET_READ_FLUSH)
1251                 die(_("expected no other sections to be sent after no 'ready'"));
1252
1253         /* return 0 if no common, 1 if there are common, or 2 if ready */
1254         return received_ready ? 2 : (received_ack ? 1 : 0);
1255 }
1256
1257 static void receive_shallow_info(struct fetch_pack_args *args,
1258                                  struct packet_reader *reader)
1259 {
1260         int line_received = 0;
1261
1262         process_section_header(reader, "shallow-info", 0);
1263         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1264                 const char *arg;
1265                 struct object_id oid;
1266
1267                 if (skip_prefix(reader->line, "shallow ", &arg)) {
1268                         if (get_oid_hex(arg, &oid))
1269                                 die(_("invalid shallow line: %s"), reader->line);
1270                         register_shallow(the_repository, &oid);
1271                         line_received = 1;
1272                         continue;
1273                 }
1274                 if (skip_prefix(reader->line, "unshallow ", &arg)) {
1275                         if (get_oid_hex(arg, &oid))
1276                                 die(_("invalid unshallow line: %s"), reader->line);
1277                         if (!lookup_object(the_repository, oid.hash))
1278                                 die(_("object not found: %s"), reader->line);
1279                         /* make sure that it is parsed as shallow */
1280                         if (!parse_object(the_repository, &oid))
1281                                 die(_("error in object: %s"), reader->line);
1282                         if (unregister_shallow(&oid))
1283                                 die(_("no shallow found: %s"), reader->line);
1284                         line_received = 1;
1285                         continue;
1286                 }
1287                 die(_("expected shallow/unshallow, got %s"), reader->line);
1288         }
1289
1290         if (reader->status != PACKET_READ_FLUSH &&
1291             reader->status != PACKET_READ_DELIM)
1292                 die(_("error processing shallow info: %d"), reader->status);
1293
1294         if (line_received) {
1295                 setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
1296                                         NULL);
1297                 args->deepen = 1;
1298         } else {
1299                 alternate_shallow_file = NULL;
1300         }
1301 }
1302
1303 static void receive_wanted_refs(struct packet_reader *reader,
1304                                 struct ref **sought, int nr_sought)
1305 {
1306         process_section_header(reader, "wanted-refs", 0);
1307         while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
1308                 struct object_id oid;
1309                 const char *end;
1310                 int i;
1311
1312                 if (parse_oid_hex(reader->line, &oid, &end) || *end++ != ' ')
1313                         die(_("expected wanted-ref, got '%s'"), reader->line);
1314
1315                 for (i = 0; i < nr_sought; i++) {
1316                         if (!strcmp(end, sought[i]->name)) {
1317                                 oidcpy(&sought[i]->old_oid, &oid);
1318                                 break;
1319                         }
1320                 }
1321
1322                 if (i == nr_sought)
1323                         die(_("unexpected wanted-ref: '%s'"), reader->line);
1324         }
1325
1326         if (reader->status != PACKET_READ_DELIM)
1327                 die(_("error processing wanted refs: %d"), reader->status);
1328 }
1329
1330 enum fetch_state {
1331         FETCH_CHECK_LOCAL = 0,
1332         FETCH_SEND_REQUEST,
1333         FETCH_PROCESS_ACKS,
1334         FETCH_GET_PACK,
1335         FETCH_DONE,
1336 };
1337
1338 static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
1339                                     int fd[2],
1340                                     const struct ref *orig_ref,
1341                                     struct ref **sought, int nr_sought,
1342                                     char **pack_lockfile)
1343 {
1344         struct ref *ref = copy_ref_list(orig_ref);
1345         enum fetch_state state = FETCH_CHECK_LOCAL;
1346         struct oidset common = OIDSET_INIT;
1347         struct packet_reader reader;
1348         int in_vain = 0;
1349         int haves_to_send = INITIAL_FLUSH;
1350         struct fetch_negotiator negotiator;
1351         fetch_negotiator_init(&negotiator, negotiation_algorithm);
1352         packet_reader_init(&reader, fd[0], NULL, 0,
1353                            PACKET_READ_CHOMP_NEWLINE |
1354                            PACKET_READ_DIE_ON_ERR_PACKET);
1355         if (git_env_bool("GIT_TEST_SIDEBAND_ALL", 1) &&
1356             server_supports_feature("fetch", "sideband-all", 0)) {
1357                 reader.use_sideband = 1;
1358                 reader.me = "fetch-pack";
1359         }
1360
1361         while (state != FETCH_DONE) {
1362                 switch (state) {
1363                 case FETCH_CHECK_LOCAL:
1364                         sort_ref_list(&ref, ref_compare_name);
1365                         QSORT(sought, nr_sought, cmp_ref_by_name);
1366
1367                         /* v2 supports these by default */
1368                         allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
1369                         use_sideband = 2;
1370                         if (args->depth > 0 || args->deepen_since || args->deepen_not)
1371                                 args->deepen = 1;
1372
1373                         /* Filter 'ref' by 'sought' and those that aren't local */
1374                         if (!args->no_dependents) {
1375                                 mark_complete_and_common_ref(&negotiator, args, &ref);
1376                                 filter_refs(args, &ref, sought, nr_sought);
1377                                 if (everything_local(args, &ref))
1378                                         state = FETCH_DONE;
1379                                 else
1380                                         state = FETCH_SEND_REQUEST;
1381
1382                                 mark_tips(&negotiator, args->negotiation_tips);
1383                                 for_each_cached_alternate(&negotiator,
1384                                                           insert_one_alternate_object);
1385                         } else {
1386                                 filter_refs(args, &ref, sought, nr_sought);
1387                                 state = FETCH_SEND_REQUEST;
1388                         }
1389                         break;
1390                 case FETCH_SEND_REQUEST:
1391                         if (send_fetch_request(&negotiator, fd[1], args, ref,
1392                                                &common,
1393                                                &haves_to_send, &in_vain,
1394                                                reader.use_sideband))
1395                                 state = FETCH_GET_PACK;
1396                         else
1397                                 state = FETCH_PROCESS_ACKS;
1398                         break;
1399                 case FETCH_PROCESS_ACKS:
1400                         /* Process ACKs/NAKs */
1401                         switch (process_acks(&negotiator, &reader, &common)) {
1402                         case 2:
1403                                 state = FETCH_GET_PACK;
1404                                 break;
1405                         case 1:
1406                                 in_vain = 0;
1407                                 /* fallthrough */
1408                         default:
1409                                 state = FETCH_SEND_REQUEST;
1410                                 break;
1411                         }
1412                         break;
1413                 case FETCH_GET_PACK:
1414                         /* Check for shallow-info section */
1415                         if (process_section_header(&reader, "shallow-info", 1))
1416                                 receive_shallow_info(args, &reader);
1417
1418                         if (process_section_header(&reader, "wanted-refs", 1))
1419                                 receive_wanted_refs(&reader, sought, nr_sought);
1420
1421                         /* get the pack */
1422                         process_section_header(&reader, "packfile", 0);
1423                         if (get_pack(args, fd, pack_lockfile))
1424                                 die(_("git fetch-pack: fetch failed."));
1425
1426                         state = FETCH_DONE;
1427                         break;
1428                 case FETCH_DONE:
1429                         continue;
1430                 }
1431         }
1432
1433         negotiator.release(&negotiator);
1434         oidset_clear(&common);
1435         return ref;
1436 }
1437
1438 static int fetch_pack_config_cb(const char *var, const char *value, void *cb)
1439 {
1440         if (strcmp(var, "fetch.fsck.skiplist") == 0) {
1441                 const char *path;
1442
1443                 if (git_config_pathname(&path, var, value))
1444                         return 1;
1445                 strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
1446                         fsck_msg_types.len ? ',' : '=', path);
1447                 free((char *)path);
1448                 return 0;
1449         }
1450
1451         if (skip_prefix(var, "fetch.fsck.", &var)) {
1452                 if (is_valid_msg_type(var, value))
1453                         strbuf_addf(&fsck_msg_types, "%c%s=%s",
1454                                 fsck_msg_types.len ? ',' : '=', var, value);
1455                 else
1456                         warning("Skipping unknown msg id '%s'", var);
1457                 return 0;
1458         }
1459
1460         return git_default_config(var, value, cb);
1461 }
1462
1463 static void fetch_pack_config(void)
1464 {
1465         git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
1466         git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
1467         git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
1468         git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
1469         git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
1470         git_config_get_string("fetch.negotiationalgorithm",
1471                               &negotiation_algorithm);
1472
1473         git_config(fetch_pack_config_cb, NULL);
1474 }
1475
1476 static void fetch_pack_setup(void)
1477 {
1478         static int did_setup;
1479         if (did_setup)
1480                 return;
1481         fetch_pack_config();
1482         if (0 <= transfer_unpack_limit)
1483                 unpack_limit = transfer_unpack_limit;
1484         else if (0 <= fetch_unpack_limit)
1485                 unpack_limit = fetch_unpack_limit;
1486         did_setup = 1;
1487 }
1488
1489 static int remove_duplicates_in_refs(struct ref **ref, int nr)
1490 {
1491         struct string_list names = STRING_LIST_INIT_NODUP;
1492         int src, dst;
1493
1494         for (src = dst = 0; src < nr; src++) {
1495                 struct string_list_item *item;
1496                 item = string_list_insert(&names, ref[src]->name);
1497                 if (item->util)
1498                         continue; /* already have it */
1499                 item->util = ref[src];
1500                 if (src != dst)
1501                         ref[dst] = ref[src];
1502                 dst++;
1503         }
1504         for (src = dst; src < nr; src++)
1505                 ref[src] = NULL;
1506         string_list_clear(&names, 0);
1507         return dst;
1508 }
1509
1510 static void update_shallow(struct fetch_pack_args *args,
1511                            struct ref **sought, int nr_sought,
1512                            struct shallow_info *si)
1513 {
1514         struct oid_array ref = OID_ARRAY_INIT;
1515         int *status;
1516         int i;
1517
1518         if (args->deepen && alternate_shallow_file) {
1519                 if (*alternate_shallow_file == '\0') { /* --unshallow */
1520                         unlink_or_warn(git_path_shallow(the_repository));
1521                         rollback_lock_file(&shallow_lock);
1522                 } else
1523                         commit_lock_file(&shallow_lock);
1524                 alternate_shallow_file = NULL;
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                         alternate_shallow_file = NULL;
1549                 }
1550                 oid_array_clear(&extra);
1551                 return;
1552         }
1553
1554         if (!si->nr_ours && !si->nr_theirs)
1555                 return;
1556
1557         remove_nonexistent_theirs_shallow(si);
1558         if (!si->nr_ours && !si->nr_theirs)
1559                 return;
1560         for (i = 0; i < nr_sought; i++)
1561                 oid_array_append(&ref, &sought[i]->old_oid);
1562         si->ref = &ref;
1563
1564         if (args->update_shallow) {
1565                 /*
1566                  * remote is also shallow, .git/shallow may be updated
1567                  * so all refs can be accepted. Make sure we only add
1568                  * shallow roots that are actually reachable from new
1569                  * refs.
1570                  */
1571                 struct oid_array extra = OID_ARRAY_INIT;
1572                 struct object_id *oid = si->shallow->oid;
1573                 assign_shallow_commits_to_refs(si, NULL, NULL);
1574                 if (!si->nr_ours && !si->nr_theirs) {
1575                         oid_array_clear(&ref);
1576                         return;
1577                 }
1578                 for (i = 0; i < si->nr_ours; i++)
1579                         oid_array_append(&extra, &oid[si->ours[i]]);
1580                 for (i = 0; i < si->nr_theirs; i++)
1581                         oid_array_append(&extra, &oid[si->theirs[i]]);
1582                 setup_alternate_shallow(&shallow_lock,
1583                                         &alternate_shallow_file,
1584                                         &extra);
1585                 commit_lock_file(&shallow_lock);
1586                 oid_array_clear(&extra);
1587                 oid_array_clear(&ref);
1588                 alternate_shallow_file = NULL;
1589                 return;
1590         }
1591
1592         /*
1593          * remote is also shallow, check what ref is safe to update
1594          * without updating .git/shallow
1595          */
1596         status = xcalloc(nr_sought, sizeof(*status));
1597         assign_shallow_commits_to_refs(si, NULL, status);
1598         if (si->nr_ours || si->nr_theirs) {
1599                 for (i = 0; i < nr_sought; i++)
1600                         if (status[i])
1601                                 sought[i]->status = REF_STATUS_REJECT_SHALLOW;
1602         }
1603         free(status);
1604         oid_array_clear(&ref);
1605 }
1606
1607 static int iterate_ref_map(void *cb_data, struct object_id *oid)
1608 {
1609         struct ref **rm = cb_data;
1610         struct ref *ref = *rm;
1611
1612         if (!ref)
1613                 return -1; /* end of the list */
1614         *rm = ref->next;
1615         oidcpy(oid, &ref->old_oid);
1616         return 0;
1617 }
1618
1619 struct ref *fetch_pack(struct fetch_pack_args *args,
1620                        int fd[], struct child_process *conn,
1621                        const struct ref *ref,
1622                        const char *dest,
1623                        struct ref **sought, int nr_sought,
1624                        struct oid_array *shallow,
1625                        char **pack_lockfile,
1626                        enum protocol_version version)
1627 {
1628         struct ref *ref_cpy;
1629         struct shallow_info si;
1630
1631         fetch_pack_setup();
1632         if (nr_sought)
1633                 nr_sought = remove_duplicates_in_refs(sought, nr_sought);
1634
1635         if (args->no_dependents && !args->filter_options.choice) {
1636                 /*
1637                  * The protocol does not support requesting that only the
1638                  * wanted objects be sent, so approximate this by setting a
1639                  * "blob:none" filter if no filter is already set. This works
1640                  * for all object types: note that wanted blobs will still be
1641                  * sent because they are directly specified as a "want".
1642                  *
1643                  * NEEDSWORK: Add an option in the protocol to request that
1644                  * only the wanted objects be sent, and implement it.
1645                  */
1646                 parse_list_objects_filter(&args->filter_options, "blob:none");
1647         }
1648
1649         if (version != protocol_v2 && !ref) {
1650                 packet_flush(fd[1]);
1651                 die(_("no matching remote head"));
1652         }
1653         prepare_shallow_info(&si, shallow);
1654         if (version == protocol_v2)
1655                 ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
1656                                            pack_lockfile);
1657         else
1658                 ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
1659                                         &si, pack_lockfile);
1660         reprepare_packed_git(the_repository);
1661
1662         if (!args->cloning && args->deepen) {
1663                 struct check_connected_options opt = CHECK_CONNECTED_INIT;
1664                 struct ref *iterator = ref_cpy;
1665                 opt.shallow_file = alternate_shallow_file;
1666                 if (args->deepen)
1667                         opt.is_deepening_fetch = 1;
1668                 if (check_connected(iterate_ref_map, &iterator, &opt)) {
1669                         error(_("remote did not send all necessary objects"));
1670                         free_refs(ref_cpy);
1671                         ref_cpy = NULL;
1672                         rollback_lock_file(&shallow_lock);
1673                         goto cleanup;
1674                 }
1675                 args->connectivity_checked = 1;
1676         }
1677
1678         update_shallow(args, sought, nr_sought, &si);
1679 cleanup:
1680         clear_shallow_info(&si);
1681         return ref_cpy;
1682 }
1683
1684 int report_unmatched_refs(struct ref **sought, int nr_sought)
1685 {
1686         int i, ret = 0;
1687
1688         for (i = 0; i < nr_sought; i++) {
1689                 if (!sought[i])
1690                         continue;
1691                 switch (sought[i]->match_status) {
1692                 case REF_MATCHED:
1693                         continue;
1694                 case REF_NOT_MATCHED:
1695                         error(_("no such remote ref %s"), sought[i]->name);
1696                         break;
1697                 case REF_UNADVERTISED_NOT_ALLOWED:
1698                         error(_("Server does not allow request for unadvertised object %s"),
1699                               sought[i]->name);
1700                         break;
1701                 }
1702                 ret = 1;
1703         }
1704         return ret;
1705 }