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