Merge branch 'js/default-branch-name'
[git] / commit.c
1 #include "cache.h"
2 #include "tag.h"
3 #include "commit.h"
4 #include "commit-graph.h"
5 #include "repository.h"
6 #include "object-store.h"
7 #include "pkt-line.h"
8 #include "utf8.h"
9 #include "diff.h"
10 #include "revision.h"
11 #include "notes.h"
12 #include "alloc.h"
13 #include "gpg-interface.h"
14 #include "mergesort.h"
15 #include "commit-slab.h"
16 #include "prio-queue.h"
17 #include "sha1-lookup.h"
18 #include "wt-status.h"
19 #include "advice.h"
20 #include "refs.h"
21 #include "commit-reach.h"
22 #include "run-command.h"
23 #include "shallow.h"
24
25 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
26
27 int save_commit_buffer = 1;
28
29 const char *commit_type = "commit";
30
31 struct commit *lookup_commit_reference_gently(struct repository *r,
32                 const struct object_id *oid, int quiet)
33 {
34         struct object *obj = deref_tag(r,
35                                        parse_object(r, oid),
36                                        NULL, 0);
37
38         if (!obj)
39                 return NULL;
40         return object_as_type(obj, OBJ_COMMIT, quiet);
41 }
42
43 struct commit *lookup_commit_reference(struct repository *r, const struct object_id *oid)
44 {
45         return lookup_commit_reference_gently(r, oid, 0);
46 }
47
48 struct commit *lookup_commit_or_die(const struct object_id *oid, const char *ref_name)
49 {
50         struct commit *c = lookup_commit_reference(the_repository, oid);
51         if (!c)
52                 die(_("could not parse %s"), ref_name);
53         if (!oideq(oid, &c->object.oid)) {
54                 warning(_("%s %s is not a commit!"),
55                         ref_name, oid_to_hex(oid));
56         }
57         return c;
58 }
59
60 struct commit *lookup_commit(struct repository *r, const struct object_id *oid)
61 {
62         struct object *obj = lookup_object(r, oid);
63         if (!obj)
64                 return create_object(r, oid, alloc_commit_node(r));
65         return object_as_type(obj, OBJ_COMMIT, 0);
66 }
67
68 struct commit *lookup_commit_reference_by_name(const char *name)
69 {
70         struct object_id oid;
71         struct commit *commit;
72
73         if (get_oid_committish(name, &oid))
74                 return NULL;
75         commit = lookup_commit_reference(the_repository, &oid);
76         if (parse_commit(commit))
77                 return NULL;
78         return commit;
79 }
80
81 static timestamp_t parse_commit_date(const char *buf, const char *tail)
82 {
83         const char *dateptr;
84
85         if (buf + 6 >= tail)
86                 return 0;
87         if (memcmp(buf, "author", 6))
88                 return 0;
89         while (buf < tail && *buf++ != '\n')
90                 /* nada */;
91         if (buf + 9 >= tail)
92                 return 0;
93         if (memcmp(buf, "committer", 9))
94                 return 0;
95         while (buf < tail && *buf++ != '>')
96                 /* nada */;
97         if (buf >= tail)
98                 return 0;
99         dateptr = buf;
100         while (buf < tail && *buf++ != '\n')
101                 /* nada */;
102         if (buf >= tail)
103                 return 0;
104         /* dateptr < buf && buf[-1] == '\n', so parsing will stop at buf-1 */
105         return parse_timestamp(dateptr, NULL, 10);
106 }
107
108 static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
109 {
110         struct commit_graft **commit_graft_table = table;
111         return commit_graft_table[index]->oid.hash;
112 }
113
114 int commit_graft_pos(struct repository *r, const unsigned char *sha1)
115 {
116         return sha1_pos(sha1, r->parsed_objects->grafts,
117                         r->parsed_objects->grafts_nr,
118                         commit_graft_sha1_access);
119 }
120
121 int register_commit_graft(struct repository *r, struct commit_graft *graft,
122                           int ignore_dups)
123 {
124         int pos = commit_graft_pos(r, graft->oid.hash);
125
126         if (0 <= pos) {
127                 if (ignore_dups)
128                         free(graft);
129                 else {
130                         free(r->parsed_objects->grafts[pos]);
131                         r->parsed_objects->grafts[pos] = graft;
132                 }
133                 return 1;
134         }
135         pos = -pos - 1;
136         ALLOC_GROW(r->parsed_objects->grafts,
137                    r->parsed_objects->grafts_nr + 1,
138                    r->parsed_objects->grafts_alloc);
139         r->parsed_objects->grafts_nr++;
140         if (pos < r->parsed_objects->grafts_nr)
141                 memmove(r->parsed_objects->grafts + pos + 1,
142                         r->parsed_objects->grafts + pos,
143                         (r->parsed_objects->grafts_nr - pos - 1) *
144                         sizeof(*r->parsed_objects->grafts));
145         r->parsed_objects->grafts[pos] = graft;
146         return 0;
147 }
148
149 struct commit_graft *read_graft_line(struct strbuf *line)
150 {
151         /* The format is just "Commit Parent1 Parent2 ...\n" */
152         int i, phase;
153         const char *tail = NULL;
154         struct commit_graft *graft = NULL;
155         struct object_id dummy_oid, *oid;
156
157         strbuf_rtrim(line);
158         if (!line->len || line->buf[0] == '#')
159                 return NULL;
160         /*
161          * phase 0 verifies line, counts hashes in line and allocates graft
162          * phase 1 fills graft
163          */
164         for (phase = 0; phase < 2; phase++) {
165                 oid = graft ? &graft->oid : &dummy_oid;
166                 if (parse_oid_hex(line->buf, oid, &tail))
167                         goto bad_graft_data;
168                 for (i = 0; *tail != '\0'; i++) {
169                         oid = graft ? &graft->parent[i] : &dummy_oid;
170                         if (!isspace(*tail++) || parse_oid_hex(tail, oid, &tail))
171                                 goto bad_graft_data;
172                 }
173                 if (!graft) {
174                         graft = xmalloc(st_add(sizeof(*graft),
175                                                st_mult(sizeof(struct object_id), i)));
176                         graft->nr_parent = i;
177                 }
178         }
179         return graft;
180
181 bad_graft_data:
182         error("bad graft data: %s", line->buf);
183         assert(!graft);
184         return NULL;
185 }
186
187 static int read_graft_file(struct repository *r, const char *graft_file)
188 {
189         FILE *fp = fopen_or_warn(graft_file, "r");
190         struct strbuf buf = STRBUF_INIT;
191         if (!fp)
192                 return -1;
193         if (advice_graft_file_deprecated)
194                 advise(_("Support for <GIT_DIR>/info/grafts is deprecated\n"
195                          "and will be removed in a future Git version.\n"
196                          "\n"
197                          "Please use \"git replace --convert-graft-file\"\n"
198                          "to convert the grafts into replace refs.\n"
199                          "\n"
200                          "Turn this message off by running\n"
201                          "\"git config advice.graftFileDeprecated false\""));
202         while (!strbuf_getwholeline(&buf, fp, '\n')) {
203                 /* The format is just "Commit Parent1 Parent2 ...\n" */
204                 struct commit_graft *graft = read_graft_line(&buf);
205                 if (!graft)
206                         continue;
207                 if (register_commit_graft(r, graft, 1))
208                         error("duplicate graft data: %s", buf.buf);
209         }
210         fclose(fp);
211         strbuf_release(&buf);
212         return 0;
213 }
214
215 void prepare_commit_graft(struct repository *r)
216 {
217         char *graft_file;
218
219         if (r->parsed_objects->commit_graft_prepared)
220                 return;
221         if (!startup_info->have_repository)
222                 return;
223
224         graft_file = get_graft_file(r);
225         read_graft_file(r, graft_file);
226         /* make sure shallows are read */
227         is_repository_shallow(r);
228         r->parsed_objects->commit_graft_prepared = 1;
229 }
230
231 struct commit_graft *lookup_commit_graft(struct repository *r, const struct object_id *oid)
232 {
233         int pos;
234         prepare_commit_graft(r);
235         pos = commit_graft_pos(r, oid->hash);
236         if (pos < 0)
237                 return NULL;
238         return r->parsed_objects->grafts[pos];
239 }
240
241 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
242 {
243         int i, ret;
244         for (i = ret = 0; i < the_repository->parsed_objects->grafts_nr && !ret; i++)
245                 ret = fn(the_repository->parsed_objects->grafts[i], cb_data);
246         return ret;
247 }
248
249 struct commit_buffer {
250         void *buffer;
251         unsigned long size;
252 };
253 define_commit_slab(buffer_slab, struct commit_buffer);
254
255 struct buffer_slab *allocate_commit_buffer_slab(void)
256 {
257         struct buffer_slab *bs = xmalloc(sizeof(*bs));
258         init_buffer_slab(bs);
259         return bs;
260 }
261
262 void free_commit_buffer_slab(struct buffer_slab *bs)
263 {
264         clear_buffer_slab(bs);
265         free(bs);
266 }
267
268 void set_commit_buffer(struct repository *r, struct commit *commit, void *buffer, unsigned long size)
269 {
270         struct commit_buffer *v = buffer_slab_at(
271                 r->parsed_objects->buffer_slab, commit);
272         v->buffer = buffer;
273         v->size = size;
274 }
275
276 const void *get_cached_commit_buffer(struct repository *r, const struct commit *commit, unsigned long *sizep)
277 {
278         struct commit_buffer *v = buffer_slab_peek(
279                 r->parsed_objects->buffer_slab, commit);
280         if (!v) {
281                 if (sizep)
282                         *sizep = 0;
283                 return NULL;
284         }
285         if (sizep)
286                 *sizep = v->size;
287         return v->buffer;
288 }
289
290 const void *repo_get_commit_buffer(struct repository *r,
291                                    const struct commit *commit,
292                                    unsigned long *sizep)
293 {
294         const void *ret = get_cached_commit_buffer(r, commit, sizep);
295         if (!ret) {
296                 enum object_type type;
297                 unsigned long size;
298                 ret = repo_read_object_file(r, &commit->object.oid, &type, &size);
299                 if (!ret)
300                         die("cannot read commit object %s",
301                             oid_to_hex(&commit->object.oid));
302                 if (type != OBJ_COMMIT)
303                         die("expected commit for %s, got %s",
304                             oid_to_hex(&commit->object.oid), type_name(type));
305                 if (sizep)
306                         *sizep = size;
307         }
308         return ret;
309 }
310
311 void repo_unuse_commit_buffer(struct repository *r,
312                               const struct commit *commit,
313                               const void *buffer)
314 {
315         struct commit_buffer *v = buffer_slab_peek(
316                 r->parsed_objects->buffer_slab, commit);
317         if (!(v && v->buffer == buffer))
318                 free((void *)buffer);
319 }
320
321 void free_commit_buffer(struct parsed_object_pool *pool, struct commit *commit)
322 {
323         struct commit_buffer *v = buffer_slab_peek(
324                 pool->buffer_slab, commit);
325         if (v) {
326                 FREE_AND_NULL(v->buffer);
327                 v->size = 0;
328         }
329 }
330
331 static inline void set_commit_tree(struct commit *c, struct tree *t)
332 {
333         c->maybe_tree = t;
334 }
335
336 struct tree *repo_get_commit_tree(struct repository *r,
337                                   const struct commit *commit)
338 {
339         if (commit->maybe_tree || !commit->object.parsed)
340                 return commit->maybe_tree;
341
342         if (commit_graph_position(commit) != COMMIT_NOT_FROM_GRAPH)
343                 return get_commit_tree_in_graph(r, commit);
344
345         return NULL;
346 }
347
348 struct object_id *get_commit_tree_oid(const struct commit *commit)
349 {
350         struct tree *tree = get_commit_tree(commit);
351         return tree ? &tree->object.oid : NULL;
352 }
353
354 void release_commit_memory(struct parsed_object_pool *pool, struct commit *c)
355 {
356         set_commit_tree(c, NULL);
357         free_commit_buffer(pool, c);
358         c->index = 0;
359         free_commit_list(c->parents);
360
361         c->object.parsed = 0;
362 }
363
364 const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
365 {
366         struct commit_buffer *v = buffer_slab_peek(
367                 the_repository->parsed_objects->buffer_slab, commit);
368         void *ret;
369
370         if (!v) {
371                 if (sizep)
372                         *sizep = 0;
373                 return NULL;
374         }
375         ret = v->buffer;
376         if (sizep)
377                 *sizep = v->size;
378
379         v->buffer = NULL;
380         v->size = 0;
381         return ret;
382 }
383
384 int parse_commit_buffer(struct repository *r, struct commit *item, const void *buffer, unsigned long size, int check_graph)
385 {
386         const char *tail = buffer;
387         const char *bufptr = buffer;
388         struct object_id parent;
389         struct commit_list **pptr;
390         struct commit_graft *graft;
391         const int tree_entry_len = the_hash_algo->hexsz + 5;
392         const int parent_entry_len = the_hash_algo->hexsz + 7;
393         struct tree *tree;
394
395         if (item->object.parsed)
396                 return 0;
397
398         if (item->parents) {
399                 /*
400                  * Presumably this is leftover from an earlier failed parse;
401                  * clear it out in preparation for us re-parsing (we'll hit the
402                  * same error, but that's good, since it lets our caller know
403                  * the result cannot be trusted.
404                  */
405                 free_commit_list(item->parents);
406                 item->parents = NULL;
407         }
408
409         tail += size;
410         if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
411                         bufptr[tree_entry_len] != '\n')
412                 return error("bogus commit object %s", oid_to_hex(&item->object.oid));
413         if (get_oid_hex(bufptr + 5, &parent) < 0)
414                 return error("bad tree pointer in commit %s",
415                              oid_to_hex(&item->object.oid));
416         tree = lookup_tree(r, &parent);
417         if (!tree)
418                 return error("bad tree pointer %s in commit %s",
419                              oid_to_hex(&parent),
420                              oid_to_hex(&item->object.oid));
421         set_commit_tree(item, tree);
422         bufptr += tree_entry_len + 1; /* "tree " + "hex sha1" + "\n" */
423         pptr = &item->parents;
424
425         graft = lookup_commit_graft(r, &item->object.oid);
426         while (bufptr + parent_entry_len < tail && !memcmp(bufptr, "parent ", 7)) {
427                 struct commit *new_parent;
428
429                 if (tail <= bufptr + parent_entry_len + 1 ||
430                     get_oid_hex(bufptr + 7, &parent) ||
431                     bufptr[parent_entry_len] != '\n')
432                         return error("bad parents in commit %s", oid_to_hex(&item->object.oid));
433                 bufptr += parent_entry_len + 1;
434                 /*
435                  * The clone is shallow if nr_parent < 0, and we must
436                  * not traverse its real parents even when we unhide them.
437                  */
438                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
439                         continue;
440                 new_parent = lookup_commit(r, &parent);
441                 if (!new_parent)
442                         return error("bad parent %s in commit %s",
443                                      oid_to_hex(&parent),
444                                      oid_to_hex(&item->object.oid));
445                 pptr = &commit_list_insert(new_parent, pptr)->next;
446         }
447         if (graft) {
448                 int i;
449                 struct commit *new_parent;
450                 for (i = 0; i < graft->nr_parent; i++) {
451                         new_parent = lookup_commit(r,
452                                                    &graft->parent[i]);
453                         if (!new_parent)
454                                 return error("bad graft parent %s in commit %s",
455                                              oid_to_hex(&graft->parent[i]),
456                                              oid_to_hex(&item->object.oid));
457                         pptr = &commit_list_insert(new_parent, pptr)->next;
458                 }
459         }
460         item->date = parse_commit_date(bufptr, tail);
461
462         if (check_graph)
463                 load_commit_graph_info(r, item);
464
465         item->object.parsed = 1;
466         return 0;
467 }
468
469 int repo_parse_commit_internal(struct repository *r,
470                                struct commit *item,
471                                int quiet_on_missing,
472                                int use_commit_graph)
473 {
474         enum object_type type;
475         void *buffer;
476         unsigned long size;
477         int ret;
478
479         if (!item)
480                 return -1;
481         if (item->object.parsed)
482                 return 0;
483         if (use_commit_graph && parse_commit_in_graph(r, item))
484                 return 0;
485         buffer = repo_read_object_file(r, &item->object.oid, &type, &size);
486         if (!buffer)
487                 return quiet_on_missing ? -1 :
488                         error("Could not read %s",
489                              oid_to_hex(&item->object.oid));
490         if (type != OBJ_COMMIT) {
491                 free(buffer);
492                 return error("Object %s not a commit",
493                              oid_to_hex(&item->object.oid));
494         }
495
496         ret = parse_commit_buffer(r, item, buffer, size, 0);
497         if (save_commit_buffer && !ret) {
498                 set_commit_buffer(r, item, buffer, size);
499                 return 0;
500         }
501         free(buffer);
502         return ret;
503 }
504
505 int repo_parse_commit_gently(struct repository *r,
506                              struct commit *item, int quiet_on_missing)
507 {
508         return repo_parse_commit_internal(r, item, quiet_on_missing, 1);
509 }
510
511 void parse_commit_or_die(struct commit *item)
512 {
513         if (parse_commit(item))
514                 die("unable to parse commit %s",
515                     item ? oid_to_hex(&item->object.oid) : "(null)");
516 }
517
518 int find_commit_subject(const char *commit_buffer, const char **subject)
519 {
520         const char *eol;
521         const char *p = commit_buffer;
522
523         while (*p && (*p != '\n' || p[1] != '\n'))
524                 p++;
525         if (*p) {
526                 p = skip_blank_lines(p + 2);
527                 eol = strchrnul(p, '\n');
528         } else
529                 eol = p;
530
531         *subject = p;
532
533         return eol - p;
534 }
535
536 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
537 {
538         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
539         new_list->item = item;
540         new_list->next = *list_p;
541         *list_p = new_list;
542         return new_list;
543 }
544
545 unsigned commit_list_count(const struct commit_list *l)
546 {
547         unsigned c = 0;
548         for (; l; l = l->next )
549                 c++;
550         return c;
551 }
552
553 struct commit_list *copy_commit_list(struct commit_list *list)
554 {
555         struct commit_list *head = NULL;
556         struct commit_list **pp = &head;
557         while (list) {
558                 pp = commit_list_append(list->item, pp);
559                 list = list->next;
560         }
561         return head;
562 }
563
564 void free_commit_list(struct commit_list *list)
565 {
566         while (list)
567                 pop_commit(&list);
568 }
569
570 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
571 {
572         struct commit_list **pp = list;
573         struct commit_list *p;
574         while ((p = *pp) != NULL) {
575                 if (p->item->date < item->date) {
576                         break;
577                 }
578                 pp = &p->next;
579         }
580         return commit_list_insert(item, pp);
581 }
582
583 static int commit_list_compare_by_date(const void *a, const void *b)
584 {
585         timestamp_t a_date = ((const struct commit_list *)a)->item->date;
586         timestamp_t b_date = ((const struct commit_list *)b)->item->date;
587         if (a_date < b_date)
588                 return 1;
589         if (a_date > b_date)
590                 return -1;
591         return 0;
592 }
593
594 static void *commit_list_get_next(const void *a)
595 {
596         return ((const struct commit_list *)a)->next;
597 }
598
599 static void commit_list_set_next(void *a, void *next)
600 {
601         ((struct commit_list *)a)->next = next;
602 }
603
604 void commit_list_sort_by_date(struct commit_list **list)
605 {
606         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
607                                 commit_list_compare_by_date);
608 }
609
610 struct commit *pop_most_recent_commit(struct commit_list **list,
611                                       unsigned int mark)
612 {
613         struct commit *ret = pop_commit(list);
614         struct commit_list *parents = ret->parents;
615
616         while (parents) {
617                 struct commit *commit = parents->item;
618                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
619                         commit->object.flags |= mark;
620                         commit_list_insert_by_date(commit, list);
621                 }
622                 parents = parents->next;
623         }
624         return ret;
625 }
626
627 static void clear_commit_marks_1(struct commit_list **plist,
628                                  struct commit *commit, unsigned int mark)
629 {
630         while (commit) {
631                 struct commit_list *parents;
632
633                 if (!(mark & commit->object.flags))
634                         return;
635
636                 commit->object.flags &= ~mark;
637
638                 parents = commit->parents;
639                 if (!parents)
640                         return;
641
642                 while ((parents = parents->next))
643                         commit_list_insert(parents->item, plist);
644
645                 commit = commit->parents->item;
646         }
647 }
648
649 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
650 {
651         struct commit_list *list = NULL;
652
653         while (nr--) {
654                 clear_commit_marks_1(&list, *commit, mark);
655                 commit++;
656         }
657         while (list)
658                 clear_commit_marks_1(&list, pop_commit(&list), mark);
659 }
660
661 void clear_commit_marks(struct commit *commit, unsigned int mark)
662 {
663         clear_commit_marks_many(1, &commit, mark);
664 }
665
666 struct commit *pop_commit(struct commit_list **stack)
667 {
668         struct commit_list *top = *stack;
669         struct commit *item = top ? top->item : NULL;
670
671         if (top) {
672                 *stack = top->next;
673                 free(top);
674         }
675         return item;
676 }
677
678 /*
679  * Topological sort support
680  */
681
682 /* count number of children that have not been emitted */
683 define_commit_slab(indegree_slab, int);
684
685 define_commit_slab(author_date_slab, timestamp_t);
686
687 void record_author_date(struct author_date_slab *author_date,
688                         struct commit *commit)
689 {
690         const char *buffer = get_commit_buffer(commit, NULL);
691         struct ident_split ident;
692         const char *ident_line;
693         size_t ident_len;
694         char *date_end;
695         timestamp_t date;
696
697         ident_line = find_commit_header(buffer, "author", &ident_len);
698         if (!ident_line)
699                 goto fail_exit; /* no author line */
700         if (split_ident_line(&ident, ident_line, ident_len) ||
701             !ident.date_begin || !ident.date_end)
702                 goto fail_exit; /* malformed "author" line */
703
704         date = parse_timestamp(ident.date_begin, &date_end, 10);
705         if (date_end != ident.date_end)
706                 goto fail_exit; /* malformed date */
707         *(author_date_slab_at(author_date, commit)) = date;
708
709 fail_exit:
710         unuse_commit_buffer(commit, buffer);
711 }
712
713 int compare_commits_by_author_date(const void *a_, const void *b_,
714                                    void *cb_data)
715 {
716         const struct commit *a = a_, *b = b_;
717         struct author_date_slab *author_date = cb_data;
718         timestamp_t a_date = *(author_date_slab_at(author_date, a));
719         timestamp_t b_date = *(author_date_slab_at(author_date, b));
720
721         /* newer commits with larger date first */
722         if (a_date < b_date)
723                 return 1;
724         else if (a_date > b_date)
725                 return -1;
726         return 0;
727 }
728
729 int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused)
730 {
731         const struct commit *a = a_, *b = b_;
732         const uint32_t generation_a = commit_graph_generation(a),
733                        generation_b = commit_graph_generation(b);
734
735         /* newer commits first */
736         if (generation_a < generation_b)
737                 return 1;
738         else if (generation_a > generation_b)
739                 return -1;
740
741         /* use date as a heuristic when generations are equal */
742         if (a->date < b->date)
743                 return 1;
744         else if (a->date > b->date)
745                 return -1;
746         return 0;
747 }
748
749 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
750 {
751         const struct commit *a = a_, *b = b_;
752         /* newer commits with larger date first */
753         if (a->date < b->date)
754                 return 1;
755         else if (a->date > b->date)
756                 return -1;
757         return 0;
758 }
759
760 /*
761  * Performs an in-place topological sort on the list supplied.
762  */
763 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
764 {
765         struct commit_list *next, *orig = *list;
766         struct commit_list **pptr;
767         struct indegree_slab indegree;
768         struct prio_queue queue;
769         struct commit *commit;
770         struct author_date_slab author_date;
771
772         if (!orig)
773                 return;
774         *list = NULL;
775
776         init_indegree_slab(&indegree);
777         memset(&queue, '\0', sizeof(queue));
778
779         switch (sort_order) {
780         default: /* REV_SORT_IN_GRAPH_ORDER */
781                 queue.compare = NULL;
782                 break;
783         case REV_SORT_BY_COMMIT_DATE:
784                 queue.compare = compare_commits_by_commit_date;
785                 break;
786         case REV_SORT_BY_AUTHOR_DATE:
787                 init_author_date_slab(&author_date);
788                 queue.compare = compare_commits_by_author_date;
789                 queue.cb_data = &author_date;
790                 break;
791         }
792
793         /* Mark them and clear the indegree */
794         for (next = orig; next; next = next->next) {
795                 struct commit *commit = next->item;
796                 *(indegree_slab_at(&indegree, commit)) = 1;
797                 /* also record the author dates, if needed */
798                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
799                         record_author_date(&author_date, commit);
800         }
801
802         /* update the indegree */
803         for (next = orig; next; next = next->next) {
804                 struct commit_list *parents = next->item->parents;
805                 while (parents) {
806                         struct commit *parent = parents->item;
807                         int *pi = indegree_slab_at(&indegree, parent);
808
809                         if (*pi)
810                                 (*pi)++;
811                         parents = parents->next;
812                 }
813         }
814
815         /*
816          * find the tips
817          *
818          * tips are nodes not reachable from any other node in the list
819          *
820          * the tips serve as a starting set for the work queue.
821          */
822         for (next = orig; next; next = next->next) {
823                 struct commit *commit = next->item;
824
825                 if (*(indegree_slab_at(&indegree, commit)) == 1)
826                         prio_queue_put(&queue, commit);
827         }
828
829         /*
830          * This is unfortunate; the initial tips need to be shown
831          * in the order given from the revision traversal machinery.
832          */
833         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
834                 prio_queue_reverse(&queue);
835
836         /* We no longer need the commit list */
837         free_commit_list(orig);
838
839         pptr = list;
840         *list = NULL;
841         while ((commit = prio_queue_get(&queue)) != NULL) {
842                 struct commit_list *parents;
843
844                 for (parents = commit->parents; parents ; parents = parents->next) {
845                         struct commit *parent = parents->item;
846                         int *pi = indegree_slab_at(&indegree, parent);
847
848                         if (!*pi)
849                                 continue;
850
851                         /*
852                          * parents are only enqueued for emission
853                          * when all their children have been emitted thereby
854                          * guaranteeing topological order.
855                          */
856                         if (--(*pi) == 1)
857                                 prio_queue_put(&queue, parent);
858                 }
859                 /*
860                  * all children of commit have already been
861                  * emitted. we can emit it now.
862                  */
863                 *(indegree_slab_at(&indegree, commit)) = 0;
864
865                 pptr = &commit_list_insert(commit, pptr)->next;
866         }
867
868         clear_indegree_slab(&indegree);
869         clear_prio_queue(&queue);
870         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
871                 clear_author_date_slab(&author_date);
872 }
873
874 struct rev_collect {
875         struct commit **commit;
876         int nr;
877         int alloc;
878         unsigned int initial : 1;
879 };
880
881 static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
882 {
883         struct commit *commit;
884
885         if (is_null_oid(oid))
886                 return;
887
888         commit = lookup_commit(the_repository, oid);
889         if (!commit ||
890             (commit->object.flags & TMP_MARK) ||
891             parse_commit(commit))
892                 return;
893
894         ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
895         revs->commit[revs->nr++] = commit;
896         commit->object.flags |= TMP_MARK;
897 }
898
899 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
900                                   const char *ident, timestamp_t timestamp,
901                                   int tz, const char *message, void *cbdata)
902 {
903         struct rev_collect *revs = cbdata;
904
905         if (revs->initial) {
906                 revs->initial = 0;
907                 add_one_commit(ooid, revs);
908         }
909         add_one_commit(noid, revs);
910         return 0;
911 }
912
913 struct commit *get_fork_point(const char *refname, struct commit *commit)
914 {
915         struct object_id oid;
916         struct rev_collect revs;
917         struct commit_list *bases;
918         int i;
919         struct commit *ret = NULL;
920         char *full_refname;
921
922         switch (dwim_ref(refname, strlen(refname), &oid, &full_refname)) {
923         case 0:
924                 die("No such ref: '%s'", refname);
925         case 1:
926                 break; /* good */
927         default:
928                 die("Ambiguous refname: '%s'", refname);
929         }
930
931         memset(&revs, 0, sizeof(revs));
932         revs.initial = 1;
933         for_each_reflog_ent(full_refname, collect_one_reflog_ent, &revs);
934
935         if (!revs.nr)
936                 add_one_commit(&oid, &revs);
937
938         for (i = 0; i < revs.nr; i++)
939                 revs.commit[i]->object.flags &= ~TMP_MARK;
940
941         bases = get_merge_bases_many(commit, revs.nr, revs.commit);
942
943         /*
944          * There should be one and only one merge base, when we found
945          * a common ancestor among reflog entries.
946          */
947         if (!bases || bases->next)
948                 goto cleanup_return;
949
950         /* And the found one must be one of the reflog entries */
951         for (i = 0; i < revs.nr; i++)
952                 if (&bases->item->object == &revs.commit[i]->object)
953                         break; /* found */
954         if (revs.nr <= i)
955                 goto cleanup_return;
956
957         ret = bases->item;
958
959 cleanup_return:
960         free_commit_list(bases);
961         free(full_refname);
962         return ret;
963 }
964
965 /*
966  * Indexed by hash algorithm identifier.
967  */
968 static const char *gpg_sig_headers[] = {
969         NULL,
970         "gpgsig",
971         "gpgsig-sha256",
972 };
973
974 static int do_sign_commit(struct strbuf *buf, const char *keyid)
975 {
976         struct strbuf sig = STRBUF_INIT;
977         int inspos, copypos;
978         const char *eoh;
979         const char *gpg_sig_header = gpg_sig_headers[hash_algo_by_ptr(the_hash_algo)];
980         int gpg_sig_header_len = strlen(gpg_sig_header);
981
982         /* find the end of the header */
983         eoh = strstr(buf->buf, "\n\n");
984         if (!eoh)
985                 inspos = buf->len;
986         else
987                 inspos = eoh - buf->buf + 1;
988
989         if (!keyid || !*keyid)
990                 keyid = get_signing_key();
991         if (sign_buffer(buf, &sig, keyid)) {
992                 strbuf_release(&sig);
993                 return -1;
994         }
995
996         for (copypos = 0; sig.buf[copypos]; ) {
997                 const char *bol = sig.buf + copypos;
998                 const char *eol = strchrnul(bol, '\n');
999                 int len = (eol - bol) + !!*eol;
1000
1001                 if (!copypos) {
1002                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1003                         inspos += gpg_sig_header_len;
1004                 }
1005                 strbuf_insertstr(buf, inspos++, " ");
1006                 strbuf_insert(buf, inspos, bol, len);
1007                 inspos += len;
1008                 copypos += len;
1009         }
1010         strbuf_release(&sig);
1011         return 0;
1012 }
1013
1014 int parse_signed_commit(const struct commit *commit,
1015                         struct strbuf *payload, struct strbuf *signature)
1016 {
1017
1018         unsigned long size;
1019         const char *buffer = get_commit_buffer(commit, &size);
1020         int in_signature, saw_signature = -1;
1021         const char *line, *tail;
1022         const char *gpg_sig_header = gpg_sig_headers[hash_algo_by_ptr(the_hash_algo)];
1023         int gpg_sig_header_len = strlen(gpg_sig_header);
1024
1025         line = buffer;
1026         tail = buffer + size;
1027         in_signature = 0;
1028         saw_signature = 0;
1029         while (line < tail) {
1030                 const char *sig = NULL;
1031                 const char *next = memchr(line, '\n', tail - line);
1032
1033                 next = next ? next + 1 : tail;
1034                 if (in_signature && line[0] == ' ')
1035                         sig = line + 1;
1036                 else if (starts_with(line, gpg_sig_header) &&
1037                          line[gpg_sig_header_len] == ' ')
1038                         sig = line + gpg_sig_header_len + 1;
1039                 if (sig) {
1040                         strbuf_add(signature, sig, next - sig);
1041                         saw_signature = 1;
1042                         in_signature = 1;
1043                 } else {
1044                         if (*line == '\n')
1045                                 /* dump the whole remainder of the buffer */
1046                                 next = tail;
1047                         strbuf_add(payload, line, next - line);
1048                         in_signature = 0;
1049                 }
1050                 line = next;
1051         }
1052         unuse_commit_buffer(commit, buffer);
1053         return saw_signature;
1054 }
1055
1056 int remove_signature(struct strbuf *buf)
1057 {
1058         const char *line = buf->buf;
1059         const char *tail = buf->buf + buf->len;
1060         int in_signature = 0;
1061         const char *sig_start = NULL;
1062         const char *sig_end = NULL;
1063
1064         while (line < tail) {
1065                 const char *next = memchr(line, '\n', tail - line);
1066                 next = next ? next + 1 : tail;
1067
1068                 if (in_signature && line[0] == ' ')
1069                         sig_end = next;
1070                 else if (starts_with(line, "gpgsig")) {
1071                         int i;
1072                         for (i = 1; i < GIT_HASH_NALGOS; i++) {
1073                                 const char *p;
1074                                 if (skip_prefix(line, gpg_sig_headers[i], &p) &&
1075                                     *p == ' ') {
1076                                         sig_start = line;
1077                                         sig_end = next;
1078                                         in_signature = 1;
1079                                 }
1080                         }
1081                 } else {
1082                         if (*line == '\n')
1083                                 /* dump the whole remainder of the buffer */
1084                                 next = tail;
1085                         in_signature = 0;
1086                 }
1087                 line = next;
1088         }
1089
1090         if (sig_start)
1091                 strbuf_remove(buf, sig_start - buf->buf, sig_end - sig_start);
1092
1093         return sig_start != NULL;
1094 }
1095
1096 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1097 {
1098         struct merge_remote_desc *desc;
1099         struct commit_extra_header *mergetag;
1100         char *buf;
1101         unsigned long size, len;
1102         enum object_type type;
1103
1104         desc = merge_remote_util(parent);
1105         if (!desc || !desc->obj)
1106                 return;
1107         buf = read_object_file(&desc->obj->oid, &type, &size);
1108         if (!buf || type != OBJ_TAG)
1109                 goto free_return;
1110         len = parse_signature(buf, size);
1111         if (size == len)
1112                 goto free_return;
1113         /*
1114          * We could verify this signature and either omit the tag when
1115          * it does not validate, but the integrator may not have the
1116          * public key of the signer of the tag he is merging, while a
1117          * later auditor may have it while auditing, so let's not run
1118          * verify-signed-buffer here for now...
1119          *
1120          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1121          *      warn("warning: signed tag unverified.");
1122          */
1123         mergetag = xcalloc(1, sizeof(*mergetag));
1124         mergetag->key = xstrdup("mergetag");
1125         mergetag->value = buf;
1126         mergetag->len = size;
1127
1128         **tail = mergetag;
1129         *tail = &mergetag->next;
1130         return;
1131
1132 free_return:
1133         free(buf);
1134 }
1135
1136 int check_commit_signature(const struct commit *commit, struct signature_check *sigc)
1137 {
1138         struct strbuf payload = STRBUF_INIT;
1139         struct strbuf signature = STRBUF_INIT;
1140         int ret = 1;
1141
1142         sigc->result = 'N';
1143
1144         if (parse_signed_commit(commit, &payload, &signature) <= 0)
1145                 goto out;
1146         ret = check_signature(payload.buf, payload.len, signature.buf,
1147                 signature.len, sigc);
1148
1149  out:
1150         strbuf_release(&payload);
1151         strbuf_release(&signature);
1152
1153         return ret;
1154 }
1155
1156 void verify_merge_signature(struct commit *commit, int verbosity,
1157                             int check_trust)
1158 {
1159         char hex[GIT_MAX_HEXSZ + 1];
1160         struct signature_check signature_check;
1161         int ret;
1162         memset(&signature_check, 0, sizeof(signature_check));
1163
1164         ret = check_commit_signature(commit, &signature_check);
1165
1166         find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
1167         switch (signature_check.result) {
1168         case 'G':
1169                 if (ret || (check_trust && signature_check.trust_level < TRUST_MARGINAL))
1170                         die(_("Commit %s has an untrusted GPG signature, "
1171                               "allegedly by %s."), hex, signature_check.signer);
1172                 break;
1173         case 'B':
1174                 die(_("Commit %s has a bad GPG signature "
1175                       "allegedly by %s."), hex, signature_check.signer);
1176         default: /* 'N' */
1177                 die(_("Commit %s does not have a GPG signature."), hex);
1178         }
1179         if (verbosity >= 0 && signature_check.result == 'G')
1180                 printf(_("Commit %s has a good GPG signature by %s\n"),
1181                        hex, signature_check.signer);
1182
1183         signature_check_clear(&signature_check);
1184 }
1185
1186 void append_merge_tag_headers(struct commit_list *parents,
1187                               struct commit_extra_header ***tail)
1188 {
1189         while (parents) {
1190                 struct commit *parent = parents->item;
1191                 handle_signed_tag(parent, tail);
1192                 parents = parents->next;
1193         }
1194 }
1195
1196 static void add_extra_header(struct strbuf *buffer,
1197                              struct commit_extra_header *extra)
1198 {
1199         strbuf_addstr(buffer, extra->key);
1200         if (extra->len)
1201                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1202         else
1203                 strbuf_addch(buffer, '\n');
1204 }
1205
1206 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1207                                                       const char **exclude)
1208 {
1209         struct commit_extra_header *extra = NULL;
1210         unsigned long size;
1211         const char *buffer = get_commit_buffer(commit, &size);
1212         extra = read_commit_extra_header_lines(buffer, size, exclude);
1213         unuse_commit_buffer(commit, buffer);
1214         return extra;
1215 }
1216
1217 int for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1218 {
1219         struct commit_extra_header *extra, *to_free;
1220         int res = 0;
1221
1222         to_free = read_commit_extra_headers(commit, NULL);
1223         for (extra = to_free; !res && extra; extra = extra->next) {
1224                 if (strcmp(extra->key, "mergetag"))
1225                         continue; /* not a merge tag */
1226                 res = fn(commit, extra, data);
1227         }
1228         free_commit_extra_headers(to_free);
1229         return res;
1230 }
1231
1232 static inline int standard_header_field(const char *field, size_t len)
1233 {
1234         return ((len == 4 && !memcmp(field, "tree", 4)) ||
1235                 (len == 6 && !memcmp(field, "parent", 6)) ||
1236                 (len == 6 && !memcmp(field, "author", 6)) ||
1237                 (len == 9 && !memcmp(field, "committer", 9)) ||
1238                 (len == 8 && !memcmp(field, "encoding", 8)));
1239 }
1240
1241 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1242 {
1243         if (!exclude)
1244                 return 0;
1245
1246         while (*exclude) {
1247                 size_t xlen = strlen(*exclude);
1248                 if (len == xlen && !memcmp(field, *exclude, xlen))
1249                         return 1;
1250                 exclude++;
1251         }
1252         return 0;
1253 }
1254
1255 static struct commit_extra_header *read_commit_extra_header_lines(
1256         const char *buffer, size_t size,
1257         const char **exclude)
1258 {
1259         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1260         const char *line, *next, *eof, *eob;
1261         struct strbuf buf = STRBUF_INIT;
1262
1263         for (line = buffer, eob = line + size;
1264              line < eob && *line != '\n';
1265              line = next) {
1266                 next = memchr(line, '\n', eob - line);
1267                 next = next ? next + 1 : eob;
1268                 if (*line == ' ') {
1269                         /* continuation */
1270                         if (it)
1271                                 strbuf_add(&buf, line + 1, next - (line + 1));
1272                         continue;
1273                 }
1274                 if (it)
1275                         it->value = strbuf_detach(&buf, &it->len);
1276                 strbuf_reset(&buf);
1277                 it = NULL;
1278
1279                 eof = memchr(line, ' ', next - line);
1280                 if (!eof)
1281                         eof = next;
1282                 else if (standard_header_field(line, eof - line) ||
1283                          excluded_header_field(line, eof - line, exclude))
1284                         continue;
1285
1286                 it = xcalloc(1, sizeof(*it));
1287                 it->key = xmemdupz(line, eof-line);
1288                 *tail = it;
1289                 tail = &it->next;
1290                 if (eof + 1 < next)
1291                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1292         }
1293         if (it)
1294                 it->value = strbuf_detach(&buf, &it->len);
1295         return extra;
1296 }
1297
1298 void free_commit_extra_headers(struct commit_extra_header *extra)
1299 {
1300         while (extra) {
1301                 struct commit_extra_header *next = extra->next;
1302                 free(extra->key);
1303                 free(extra->value);
1304                 free(extra);
1305                 extra = next;
1306         }
1307 }
1308
1309 int commit_tree(const char *msg, size_t msg_len, const struct object_id *tree,
1310                 struct commit_list *parents, struct object_id *ret,
1311                 const char *author, const char *sign_commit)
1312 {
1313         struct commit_extra_header *extra = NULL, **tail = &extra;
1314         int result;
1315
1316         append_merge_tag_headers(parents, &tail);
1317         result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1318                                       author, sign_commit, extra);
1319         free_commit_extra_headers(extra);
1320         return result;
1321 }
1322
1323 static int find_invalid_utf8(const char *buf, int len)
1324 {
1325         int offset = 0;
1326         static const unsigned int max_codepoint[] = {
1327                 0x7f, 0x7ff, 0xffff, 0x10ffff
1328         };
1329
1330         while (len) {
1331                 unsigned char c = *buf++;
1332                 int bytes, bad_offset;
1333                 unsigned int codepoint;
1334                 unsigned int min_val, max_val;
1335
1336                 len--;
1337                 offset++;
1338
1339                 /* Simple US-ASCII? No worries. */
1340                 if (c < 0x80)
1341                         continue;
1342
1343                 bad_offset = offset-1;
1344
1345                 /*
1346                  * Count how many more high bits set: that's how
1347                  * many more bytes this sequence should have.
1348                  */
1349                 bytes = 0;
1350                 while (c & 0x40) {
1351                         c <<= 1;
1352                         bytes++;
1353                 }
1354
1355                 /*
1356                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1357                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1358                  */
1359                 if (bytes < 1 || 3 < bytes)
1360                         return bad_offset;
1361
1362                 /* Do we *have* that many bytes? */
1363                 if (len < bytes)
1364                         return bad_offset;
1365
1366                 /*
1367                  * Place the encoded bits at the bottom of the value and compute the
1368                  * valid range.
1369                  */
1370                 codepoint = (c & 0x7f) >> bytes;
1371                 min_val = max_codepoint[bytes-1] + 1;
1372                 max_val = max_codepoint[bytes];
1373
1374                 offset += bytes;
1375                 len -= bytes;
1376
1377                 /* And verify that they are good continuation bytes */
1378                 do {
1379                         codepoint <<= 6;
1380                         codepoint |= *buf & 0x3f;
1381                         if ((*buf++ & 0xc0) != 0x80)
1382                                 return bad_offset;
1383                 } while (--bytes);
1384
1385                 /* Reject codepoints that are out of range for the sequence length. */
1386                 if (codepoint < min_val || codepoint > max_val)
1387                         return bad_offset;
1388                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1389                 if ((codepoint & 0x1ff800) == 0xd800)
1390                         return bad_offset;
1391                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1392                 if ((codepoint & 0xfffe) == 0xfffe)
1393                         return bad_offset;
1394                 /* So are anything in the range U+FDD0..U+FDEF. */
1395                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1396                         return bad_offset;
1397         }
1398         return -1;
1399 }
1400
1401 /*
1402  * This verifies that the buffer is in proper utf8 format.
1403  *
1404  * If it isn't, it assumes any non-utf8 characters are Latin1,
1405  * and does the conversion.
1406  */
1407 static int verify_utf8(struct strbuf *buf)
1408 {
1409         int ok = 1;
1410         long pos = 0;
1411
1412         for (;;) {
1413                 int bad;
1414                 unsigned char c;
1415                 unsigned char replace[2];
1416
1417                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1418                 if (bad < 0)
1419                         return ok;
1420                 pos += bad;
1421                 ok = 0;
1422                 c = buf->buf[pos];
1423                 strbuf_remove(buf, pos, 1);
1424
1425                 /* We know 'c' must be in the range 128-255 */
1426                 replace[0] = 0xc0 + (c >> 6);
1427                 replace[1] = 0x80 + (c & 0x3f);
1428                 strbuf_insert(buf, pos, replace, 2);
1429                 pos += 2;
1430         }
1431 }
1432
1433 static const char commit_utf8_warn[] =
1434 N_("Warning: commit message did not conform to UTF-8.\n"
1435    "You may want to amend it after fixing the message, or set the config\n"
1436    "variable i18n.commitencoding to the encoding your project uses.\n");
1437
1438 int commit_tree_extended(const char *msg, size_t msg_len,
1439                          const struct object_id *tree,
1440                          struct commit_list *parents, struct object_id *ret,
1441                          const char *author, const char *sign_commit,
1442                          struct commit_extra_header *extra)
1443 {
1444         int result;
1445         int encoding_is_utf8;
1446         struct strbuf buffer;
1447
1448         assert_oid_type(tree, OBJ_TREE);
1449
1450         if (memchr(msg, '\0', msg_len))
1451                 return error("a NUL byte in commit log message not allowed.");
1452
1453         /* Not having i18n.commitencoding is the same as having utf-8 */
1454         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1455
1456         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1457         strbuf_addf(&buffer, "tree %s\n", oid_to_hex(tree));
1458
1459         /*
1460          * NOTE! This ordering means that the same exact tree merged with a
1461          * different order of parents will be a _different_ changeset even
1462          * if everything else stays the same.
1463          */
1464         while (parents) {
1465                 struct commit *parent = pop_commit(&parents);
1466                 strbuf_addf(&buffer, "parent %s\n",
1467                             oid_to_hex(&parent->object.oid));
1468         }
1469
1470         /* Person/date information */
1471         if (!author)
1472                 author = git_author_info(IDENT_STRICT);
1473         strbuf_addf(&buffer, "author %s\n", author);
1474         strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1475         if (!encoding_is_utf8)
1476                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1477
1478         while (extra) {
1479                 add_extra_header(&buffer, extra);
1480                 extra = extra->next;
1481         }
1482         strbuf_addch(&buffer, '\n');
1483
1484         /* And add the comment */
1485         strbuf_add(&buffer, msg, msg_len);
1486
1487         /* And check the encoding */
1488         if (encoding_is_utf8 && !verify_utf8(&buffer))
1489                 fprintf(stderr, _(commit_utf8_warn));
1490
1491         if (sign_commit && do_sign_commit(&buffer, sign_commit)) {
1492                 result = -1;
1493                 goto out;
1494         }
1495
1496         result = write_object_file(buffer.buf, buffer.len, commit_type, ret);
1497 out:
1498         strbuf_release(&buffer);
1499         return result;
1500 }
1501
1502 define_commit_slab(merge_desc_slab, struct merge_remote_desc *);
1503 static struct merge_desc_slab merge_desc_slab = COMMIT_SLAB_INIT(1, merge_desc_slab);
1504
1505 struct merge_remote_desc *merge_remote_util(struct commit *commit)
1506 {
1507         return *merge_desc_slab_at(&merge_desc_slab, commit);
1508 }
1509
1510 void set_merge_remote_desc(struct commit *commit,
1511                            const char *name, struct object *obj)
1512 {
1513         struct merge_remote_desc *desc;
1514         FLEX_ALLOC_STR(desc, name, name);
1515         desc->obj = obj;
1516         *merge_desc_slab_at(&merge_desc_slab, commit) = desc;
1517 }
1518
1519 struct commit *get_merge_parent(const char *name)
1520 {
1521         struct object *obj;
1522         struct commit *commit;
1523         struct object_id oid;
1524         if (get_oid(name, &oid))
1525                 return NULL;
1526         obj = parse_object(the_repository, &oid);
1527         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1528         if (commit && !merge_remote_util(commit))
1529                 set_merge_remote_desc(commit, name, obj);
1530         return commit;
1531 }
1532
1533 /*
1534  * Append a commit to the end of the commit_list.
1535  *
1536  * next starts by pointing to the variable that holds the head of an
1537  * empty commit_list, and is updated to point to the "next" field of
1538  * the last item on the list as new commits are appended.
1539  *
1540  * Usage example:
1541  *
1542  *     struct commit_list *list;
1543  *     struct commit_list **next = &list;
1544  *
1545  *     next = commit_list_append(c1, next);
1546  *     next = commit_list_append(c2, next);
1547  *     assert(commit_list_count(list) == 2);
1548  *     return list;
1549  */
1550 struct commit_list **commit_list_append(struct commit *commit,
1551                                         struct commit_list **next)
1552 {
1553         struct commit_list *new_commit = xmalloc(sizeof(struct commit_list));
1554         new_commit->item = commit;
1555         *next = new_commit;
1556         new_commit->next = NULL;
1557         return &new_commit->next;
1558 }
1559
1560 const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
1561 {
1562         int key_len = strlen(key);
1563         const char *line = msg;
1564
1565         while (line) {
1566                 const char *eol = strchrnul(line, '\n');
1567
1568                 if (line == eol)
1569                         return NULL;
1570
1571                 if (eol - line > key_len &&
1572                     !strncmp(line, key, key_len) &&
1573                     line[key_len] == ' ') {
1574                         *out_len = eol - line - key_len - 1;
1575                         return line + key_len + 1;
1576                 }
1577                 line = *eol ? eol + 1 : NULL;
1578         }
1579         return NULL;
1580 }
1581
1582 /*
1583  * Inspect the given string and determine the true "end" of the log message, in
1584  * order to find where to put a new Signed-off-by: line.  Ignored are
1585  * trailing comment lines and blank lines.  To support "git commit -s
1586  * --amend" on an existing commit, we also ignore "Conflicts:".  To
1587  * support "git commit -v", we truncate at cut lines.
1588  *
1589  * Returns the number of bytes from the tail to ignore, to be fed as
1590  * the second parameter to append_signoff().
1591  */
1592 size_t ignore_non_trailer(const char *buf, size_t len)
1593 {
1594         size_t boc = 0;
1595         size_t bol = 0;
1596         int in_old_conflicts_block = 0;
1597         size_t cutoff = wt_status_locate_end(buf, len);
1598
1599         while (bol < cutoff) {
1600                 const char *next_line = memchr(buf + bol, '\n', len - bol);
1601
1602                 if (!next_line)
1603                         next_line = buf + len;
1604                 else
1605                         next_line++;
1606
1607                 if (buf[bol] == comment_line_char || buf[bol] == '\n') {
1608                         /* is this the first of the run of comments? */
1609                         if (!boc)
1610                                 boc = bol;
1611                         /* otherwise, it is just continuing */
1612                 } else if (starts_with(buf + bol, "Conflicts:\n")) {
1613                         in_old_conflicts_block = 1;
1614                         if (!boc)
1615                                 boc = bol;
1616                 } else if (in_old_conflicts_block && buf[bol] == '\t') {
1617                         ; /* a pathname in the conflicts block */
1618                 } else if (boc) {
1619                         /* the previous was not trailing comment */
1620                         boc = 0;
1621                         in_old_conflicts_block = 0;
1622                 }
1623                 bol = next_line - buf;
1624         }
1625         return boc ? len - boc : len - cutoff;
1626 }
1627
1628 int run_commit_hook(int editor_is_used, const char *index_file,
1629                     const char *name, ...)
1630 {
1631         struct argv_array hook_env = ARGV_ARRAY_INIT;
1632         va_list args;
1633         int ret;
1634
1635         argv_array_pushf(&hook_env, "GIT_INDEX_FILE=%s", index_file);
1636
1637         /*
1638          * Let the hook know that no editor will be launched.
1639          */
1640         if (!editor_is_used)
1641                 argv_array_push(&hook_env, "GIT_EDITOR=:");
1642
1643         va_start(args, name);
1644         ret = run_hook_ve(hook_env.argv,name, args);
1645         va_end(args);
1646         argv_array_clear(&hook_env);
1647
1648         return ret;
1649 }