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