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