Merge branch 'js/maint-http-push'
[git] / revision.c
1 #include "cache.h"
2 #include "tag.h"
3 #include "blob.h"
4 #include "tree.h"
5 #include "commit.h"
6 #include "diff.h"
7 #include "refs.h"
8 #include "revision.h"
9 #include "grep.h"
10 #include "reflog-walk.h"
11 #include "patch-ids.h"
12
13 volatile show_early_output_fn_t show_early_output;
14
15 static char *path_name(struct name_path *path, const char *name)
16 {
17         struct name_path *p;
18         char *n, *m;
19         int nlen = strlen(name);
20         int len = nlen + 1;
21
22         for (p = path; p; p = p->up) {
23                 if (p->elem_len)
24                         len += p->elem_len + 1;
25         }
26         n = xmalloc(len);
27         m = n + len - (nlen + 1);
28         strcpy(m, name);
29         for (p = path; p; p = p->up) {
30                 if (p->elem_len) {
31                         m -= p->elem_len + 1;
32                         memcpy(m, p->elem, p->elem_len);
33                         m[p->elem_len] = '/';
34                 }
35         }
36         return n;
37 }
38
39 void add_object(struct object *obj,
40                 struct object_array *p,
41                 struct name_path *path,
42                 const char *name)
43 {
44         add_object_array(obj, path_name(path, name), p);
45 }
46
47 static void mark_blob_uninteresting(struct blob *blob)
48 {
49         if (!blob)
50                 return;
51         if (blob->object.flags & UNINTERESTING)
52                 return;
53         blob->object.flags |= UNINTERESTING;
54 }
55
56 void mark_tree_uninteresting(struct tree *tree)
57 {
58         struct tree_desc desc;
59         struct name_entry entry;
60         struct object *obj = &tree->object;
61
62         if (!tree)
63                 return;
64         if (obj->flags & UNINTERESTING)
65                 return;
66         obj->flags |= UNINTERESTING;
67         if (!has_sha1_file(obj->sha1))
68                 return;
69         if (parse_tree(tree) < 0)
70                 die("bad tree %s", sha1_to_hex(obj->sha1));
71
72         init_tree_desc(&desc, tree->buffer, tree->size);
73         while (tree_entry(&desc, &entry)) {
74                 switch (object_type(entry.mode)) {
75                 case OBJ_TREE:
76                         mark_tree_uninteresting(lookup_tree(entry.sha1));
77                         break;
78                 case OBJ_BLOB:
79                         mark_blob_uninteresting(lookup_blob(entry.sha1));
80                         break;
81                 default:
82                         /* Subproject commit - not in this repository */
83                         break;
84                 }
85         }
86
87         /*
88          * We don't care about the tree any more
89          * after it has been marked uninteresting.
90          */
91         free(tree->buffer);
92         tree->buffer = NULL;
93 }
94
95 void mark_parents_uninteresting(struct commit *commit)
96 {
97         struct commit_list *parents = commit->parents;
98
99         while (parents) {
100                 struct commit *commit = parents->item;
101                 if (!(commit->object.flags & UNINTERESTING)) {
102                         commit->object.flags |= UNINTERESTING;
103
104                         /*
105                          * Normally we haven't parsed the parent
106                          * yet, so we won't have a parent of a parent
107                          * here. However, it may turn out that we've
108                          * reached this commit some other way (where it
109                          * wasn't uninteresting), in which case we need
110                          * to mark its parents recursively too..
111                          */
112                         if (commit->parents)
113                                 mark_parents_uninteresting(commit);
114                 }
115
116                 /*
117                  * A missing commit is ok iff its parent is marked
118                  * uninteresting.
119                  *
120                  * We just mark such a thing parsed, so that when
121                  * it is popped next time around, we won't be trying
122                  * to parse it and get an error.
123                  */
124                 if (!has_sha1_file(commit->object.sha1))
125                         commit->object.parsed = 1;
126                 parents = parents->next;
127         }
128 }
129
130 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
131 {
132         if (revs->no_walk && (obj->flags & UNINTERESTING))
133                 die("object ranges do not make sense when not walking revisions");
134         if (revs->reflog_info && obj->type == OBJ_COMMIT &&
135                         add_reflog_for_walk(revs->reflog_info,
136                                 (struct commit *)obj, name))
137                 return;
138         add_object_array_with_mode(obj, name, &revs->pending, mode);
139 }
140
141 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
142 {
143         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
144 }
145
146 void add_head_to_pending(struct rev_info *revs)
147 {
148         unsigned char sha1[20];
149         struct object *obj;
150         if (get_sha1("HEAD", sha1))
151                 return;
152         obj = parse_object(sha1);
153         if (!obj)
154                 return;
155         add_pending_object(revs, obj, "HEAD");
156 }
157
158 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
159 {
160         struct object *object;
161
162         object = parse_object(sha1);
163         if (!object)
164                 die("bad object %s", name);
165         object->flags |= flags;
166         return object;
167 }
168
169 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
170 {
171         unsigned long flags = object->flags;
172
173         /*
174          * Tag object? Look what it points to..
175          */
176         while (object->type == OBJ_TAG) {
177                 struct tag *tag = (struct tag *) object;
178                 if (revs->tag_objects && !(flags & UNINTERESTING))
179                         add_pending_object(revs, object, tag->tag);
180                 if (!tag->tagged)
181                         die("bad tag");
182                 object = parse_object(tag->tagged->sha1);
183                 if (!object)
184                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
185         }
186
187         /*
188          * Commit object? Just return it, we'll do all the complex
189          * reachability crud.
190          */
191         if (object->type == OBJ_COMMIT) {
192                 struct commit *commit = (struct commit *)object;
193                 if (parse_commit(commit) < 0)
194                         die("unable to parse commit %s", name);
195                 if (flags & UNINTERESTING) {
196                         commit->object.flags |= UNINTERESTING;
197                         mark_parents_uninteresting(commit);
198                         revs->limited = 1;
199                 }
200                 return commit;
201         }
202
203         /*
204          * Tree object? Either mark it uniniteresting, or add it
205          * to the list of objects to look at later..
206          */
207         if (object->type == OBJ_TREE) {
208                 struct tree *tree = (struct tree *)object;
209                 if (!revs->tree_objects)
210                         return NULL;
211                 if (flags & UNINTERESTING) {
212                         mark_tree_uninteresting(tree);
213                         return NULL;
214                 }
215                 add_pending_object(revs, object, "");
216                 return NULL;
217         }
218
219         /*
220          * Blob object? You know the drill by now..
221          */
222         if (object->type == OBJ_BLOB) {
223                 struct blob *blob = (struct blob *)object;
224                 if (!revs->blob_objects)
225                         return NULL;
226                 if (flags & UNINTERESTING) {
227                         mark_blob_uninteresting(blob);
228                         return NULL;
229                 }
230                 add_pending_object(revs, object, "");
231                 return NULL;
232         }
233         die("%s is unknown object", name);
234 }
235
236 static int everybody_uninteresting(struct commit_list *orig)
237 {
238         struct commit_list *list = orig;
239         while (list) {
240                 struct commit *commit = list->item;
241                 list = list->next;
242                 if (commit->object.flags & UNINTERESTING)
243                         continue;
244                 return 0;
245         }
246         return 1;
247 }
248
249 /*
250  * The goal is to get REV_TREE_NEW as the result only if the
251  * diff consists of all '+' (and no other changes), and
252  * REV_TREE_DIFFERENT otherwise (of course if the trees are
253  * the same we want REV_TREE_SAME).  That means that once we
254  * get to REV_TREE_DIFFERENT, we do not have to look any further.
255  */
256 static int tree_difference = REV_TREE_SAME;
257
258 static void file_add_remove(struct diff_options *options,
259                     int addremove, unsigned mode,
260                     const unsigned char *sha1,
261                     const char *base, const char *path)
262 {
263         int diff = REV_TREE_DIFFERENT;
264
265         /*
266          * Is it an add of a new file? It means that the old tree
267          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
268          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
269          * (and if it already was "REV_TREE_NEW", we'll keep it
270          * "REV_TREE_NEW" of course).
271          */
272         if (addremove == '+') {
273                 diff = tree_difference;
274                 if (diff != REV_TREE_SAME)
275                         return;
276                 diff = REV_TREE_NEW;
277         }
278         tree_difference = diff;
279         if (tree_difference == REV_TREE_DIFFERENT)
280                 DIFF_OPT_SET(options, HAS_CHANGES);
281 }
282
283 static void file_change(struct diff_options *options,
284                  unsigned old_mode, unsigned new_mode,
285                  const unsigned char *old_sha1,
286                  const unsigned char *new_sha1,
287                  const char *base, const char *path)
288 {
289         tree_difference = REV_TREE_DIFFERENT;
290         DIFF_OPT_SET(options, HAS_CHANGES);
291 }
292
293 static int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
294 {
295         if (!t1)
296                 return REV_TREE_NEW;
297         if (!t2)
298                 return REV_TREE_DIFFERENT;
299         tree_difference = REV_TREE_SAME;
300         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
301         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
302                            &revs->pruning) < 0)
303                 return REV_TREE_DIFFERENT;
304         return tree_difference;
305 }
306
307 static int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
308 {
309         int retval;
310         void *tree;
311         unsigned long size;
312         struct tree_desc empty, real;
313
314         if (!t1)
315                 return 0;
316
317         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
318         if (!tree)
319                 return 0;
320         init_tree_desc(&real, tree, size);
321         init_tree_desc(&empty, "", 0);
322
323         tree_difference = REV_TREE_SAME;
324         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
325         retval = diff_tree(&empty, &real, "", &revs->pruning);
326         free(tree);
327
328         return retval >= 0 && (tree_difference == REV_TREE_SAME);
329 }
330
331 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
332 {
333         struct commit_list **pp, *parent;
334         int tree_changed = 0, tree_same = 0;
335
336         /*
337          * If we don't do pruning, everything is interesting
338          */
339         if (!revs->prune)
340                 return;
341
342         if (!commit->tree)
343                 return;
344
345         if (!commit->parents) {
346                 if (rev_same_tree_as_empty(revs, commit->tree))
347                         commit->object.flags |= TREESAME;
348                 return;
349         }
350
351         /*
352          * Normal non-merge commit? If we don't want to make the
353          * history dense, we consider it always to be a change..
354          */
355         if (!revs->dense && !commit->parents->next)
356                 return;
357
358         pp = &commit->parents;
359         while ((parent = *pp) != NULL) {
360                 struct commit *p = parent->item;
361
362                 if (parse_commit(p) < 0)
363                         die("cannot simplify commit %s (because of %s)",
364                             sha1_to_hex(commit->object.sha1),
365                             sha1_to_hex(p->object.sha1));
366                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
367                 case REV_TREE_SAME:
368                         tree_same = 1;
369                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
370                                 /* Even if a merge with an uninteresting
371                                  * side branch brought the entire change
372                                  * we are interested in, we do not want
373                                  * to lose the other branches of this
374                                  * merge, so we just keep going.
375                                  */
376                                 pp = &parent->next;
377                                 continue;
378                         }
379                         parent->next = NULL;
380                         commit->parents = parent;
381                         commit->object.flags |= TREESAME;
382                         return;
383
384                 case REV_TREE_NEW:
385                         if (revs->remove_empty_trees &&
386                             rev_same_tree_as_empty(revs, p->tree)) {
387                                 /* We are adding all the specified
388                                  * paths from this parent, so the
389                                  * history beyond this parent is not
390                                  * interesting.  Remove its parents
391                                  * (they are grandparents for us).
392                                  * IOW, we pretend this parent is a
393                                  * "root" commit.
394                                  */
395                                 if (parse_commit(p) < 0)
396                                         die("cannot simplify commit %s (invalid %s)",
397                                             sha1_to_hex(commit->object.sha1),
398                                             sha1_to_hex(p->object.sha1));
399                                 p->parents = NULL;
400                         }
401                 /* fallthrough */
402                 case REV_TREE_DIFFERENT:
403                         tree_changed = 1;
404                         pp = &parent->next;
405                         continue;
406                 }
407                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
408         }
409         if (tree_changed && !tree_same)
410                 return;
411         commit->object.flags |= TREESAME;
412 }
413
414 static int add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
415 {
416         struct commit_list *parent = commit->parents;
417         unsigned left_flag;
418         int add, rest;
419
420         if (commit->object.flags & ADDED)
421                 return 0;
422         commit->object.flags |= ADDED;
423
424         /*
425          * If the commit is uninteresting, don't try to
426          * prune parents - we want the maximal uninteresting
427          * set.
428          *
429          * Normally we haven't parsed the parent
430          * yet, so we won't have a parent of a parent
431          * here. However, it may turn out that we've
432          * reached this commit some other way (where it
433          * wasn't uninteresting), in which case we need
434          * to mark its parents recursively too..
435          */
436         if (commit->object.flags & UNINTERESTING) {
437                 while (parent) {
438                         struct commit *p = parent->item;
439                         parent = parent->next;
440                         if (parse_commit(p) < 0)
441                                 return -1;
442                         p->object.flags |= UNINTERESTING;
443                         if (p->parents)
444                                 mark_parents_uninteresting(p);
445                         if (p->object.flags & SEEN)
446                                 continue;
447                         p->object.flags |= SEEN;
448                         insert_by_date(p, list);
449                 }
450                 return 0;
451         }
452
453         /*
454          * Ok, the commit wasn't uninteresting. Try to
455          * simplify the commit history and find the parent
456          * that has no differences in the path set if one exists.
457          */
458         try_to_simplify_commit(revs, commit);
459
460         if (revs->no_walk)
461                 return 0;
462
463         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
464
465         rest = !revs->first_parent_only;
466         for (parent = commit->parents, add = 1; parent; add = rest) {
467                 struct commit *p = parent->item;
468
469                 parent = parent->next;
470                 if (parse_commit(p) < 0)
471                         return -1;
472                 p->object.flags |= left_flag;
473                 if (p->object.flags & SEEN)
474                         continue;
475                 p->object.flags |= SEEN;
476                 if (add)
477                         insert_by_date(p, list);
478         }
479         return 0;
480 }
481
482 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
483 {
484         struct commit_list *p;
485         int left_count = 0, right_count = 0;
486         int left_first;
487         struct patch_ids ids;
488
489         /* First count the commits on the left and on the right */
490         for (p = list; p; p = p->next) {
491                 struct commit *commit = p->item;
492                 unsigned flags = commit->object.flags;
493                 if (flags & BOUNDARY)
494                         ;
495                 else if (flags & SYMMETRIC_LEFT)
496                         left_count++;
497                 else
498                         right_count++;
499         }
500
501         left_first = left_count < right_count;
502         init_patch_ids(&ids);
503         if (revs->diffopt.nr_paths) {
504                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
505                 ids.diffopts.paths = revs->diffopt.paths;
506                 ids.diffopts.pathlens = revs->diffopt.pathlens;
507         }
508
509         /* Compute patch-ids for one side */
510         for (p = list; p; p = p->next) {
511                 struct commit *commit = p->item;
512                 unsigned flags = commit->object.flags;
513
514                 if (flags & BOUNDARY)
515                         continue;
516                 /*
517                  * If we have fewer left, left_first is set and we omit
518                  * commits on the right branch in this loop.  If we have
519                  * fewer right, we skip the left ones.
520                  */
521                 if (left_first != !!(flags & SYMMETRIC_LEFT))
522                         continue;
523                 commit->util = add_commit_patch_id(commit, &ids);
524         }
525
526         /* Check the other side */
527         for (p = list; p; p = p->next) {
528                 struct commit *commit = p->item;
529                 struct patch_id *id;
530                 unsigned flags = commit->object.flags;
531
532                 if (flags & BOUNDARY)
533                         continue;
534                 /*
535                  * If we have fewer left, left_first is set and we omit
536                  * commits on the left branch in this loop.
537                  */
538                 if (left_first == !!(flags & SYMMETRIC_LEFT))
539                         continue;
540
541                 /*
542                  * Have we seen the same patch id?
543                  */
544                 id = has_commit_patch_id(commit, &ids);
545                 if (!id)
546                         continue;
547                 id->seen = 1;
548                 commit->object.flags |= SHOWN;
549         }
550
551         /* Now check the original side for seen ones */
552         for (p = list; p; p = p->next) {
553                 struct commit *commit = p->item;
554                 struct patch_id *ent;
555
556                 ent = commit->util;
557                 if (!ent)
558                         continue;
559                 if (ent->seen)
560                         commit->object.flags |= SHOWN;
561                 commit->util = NULL;
562         }
563
564         free_patch_ids(&ids);
565 }
566
567 static void add_to_list(struct commit_list **p, struct commit *commit, struct commit_list *n)
568 {
569         p = &commit_list_insert(commit, p)->next;
570         *p = n;
571 }
572
573 static int limit_list(struct rev_info *revs)
574 {
575         struct commit_list *list = revs->commits;
576         struct commit_list *newlist = NULL;
577         struct commit_list **p = &newlist;
578
579         while (list) {
580                 struct commit_list *entry = list;
581                 struct commit *commit = list->item;
582                 struct object *obj = &commit->object;
583                 show_early_output_fn_t show;
584
585                 list = list->next;
586                 free(entry);
587
588                 if (revs->max_age != -1 && (commit->date < revs->max_age))
589                         obj->flags |= UNINTERESTING;
590                 if (add_parents_to_list(revs, commit, &list) < 0)
591                         return -1;
592                 if (obj->flags & UNINTERESTING) {
593                         mark_parents_uninteresting(commit);
594                         if (everybody_uninteresting(list)) {
595                                 if (revs->show_all)
596                                         add_to_list(p, commit, list);
597                                 break;
598                         }
599                         if (!revs->show_all)
600                                 continue;
601                 }
602                 if (revs->min_age != -1 && (commit->date > revs->min_age))
603                         continue;
604                 p = &commit_list_insert(commit, p)->next;
605
606                 show = show_early_output;
607                 if (!show)
608                         continue;
609
610                 show(revs, newlist);
611                 show_early_output = NULL;
612         }
613         if (revs->cherry_pick)
614                 cherry_pick_list(newlist, revs);
615
616         revs->commits = newlist;
617         return 0;
618 }
619
620 struct all_refs_cb {
621         int all_flags;
622         int warned_bad_reflog;
623         struct rev_info *all_revs;
624         const char *name_for_errormsg;
625 };
626
627 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
628 {
629         struct all_refs_cb *cb = cb_data;
630         struct object *object = get_reference(cb->all_revs, path, sha1,
631                                               cb->all_flags);
632         add_pending_object(cb->all_revs, object, path);
633         return 0;
634 }
635
636 static void handle_all(struct rev_info *revs, unsigned flags)
637 {
638         struct all_refs_cb cb;
639         cb.all_revs = revs;
640         cb.all_flags = flags;
641         for_each_ref(handle_one_ref, &cb);
642 }
643
644 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
645 {
646         struct all_refs_cb *cb = cb_data;
647         if (!is_null_sha1(sha1)) {
648                 struct object *o = parse_object(sha1);
649                 if (o) {
650                         o->flags |= cb->all_flags;
651                         add_pending_object(cb->all_revs, o, "");
652                 }
653                 else if (!cb->warned_bad_reflog) {
654                         warning("reflog of '%s' references pruned commits",
655                                 cb->name_for_errormsg);
656                         cb->warned_bad_reflog = 1;
657                 }
658         }
659 }
660
661 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
662                 const char *email, unsigned long timestamp, int tz,
663                 const char *message, void *cb_data)
664 {
665         handle_one_reflog_commit(osha1, cb_data);
666         handle_one_reflog_commit(nsha1, cb_data);
667         return 0;
668 }
669
670 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
671 {
672         struct all_refs_cb *cb = cb_data;
673         cb->warned_bad_reflog = 0;
674         cb->name_for_errormsg = path;
675         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
676         return 0;
677 }
678
679 static void handle_reflog(struct rev_info *revs, unsigned flags)
680 {
681         struct all_refs_cb cb;
682         cb.all_revs = revs;
683         cb.all_flags = flags;
684         for_each_reflog(handle_one_reflog, &cb);
685 }
686
687 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
688 {
689         unsigned char sha1[20];
690         struct object *it;
691         struct commit *commit;
692         struct commit_list *parents;
693
694         if (*arg == '^') {
695                 flags ^= UNINTERESTING;
696                 arg++;
697         }
698         if (get_sha1(arg, sha1))
699                 return 0;
700         while (1) {
701                 it = get_reference(revs, arg, sha1, 0);
702                 if (it->type != OBJ_TAG)
703                         break;
704                 if (!((struct tag*)it)->tagged)
705                         return 0;
706                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
707         }
708         if (it->type != OBJ_COMMIT)
709                 return 0;
710         commit = (struct commit *)it;
711         for (parents = commit->parents; parents; parents = parents->next) {
712                 it = &parents->item->object;
713                 it->flags |= flags;
714                 add_pending_object(revs, it, arg);
715         }
716         return 1;
717 }
718
719 void init_revisions(struct rev_info *revs, const char *prefix)
720 {
721         memset(revs, 0, sizeof(*revs));
722
723         revs->abbrev = DEFAULT_ABBREV;
724         revs->ignore_merges = 1;
725         revs->simplify_history = 1;
726         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
727         DIFF_OPT_SET(&revs->pruning, QUIET);
728         revs->pruning.add_remove = file_add_remove;
729         revs->pruning.change = file_change;
730         revs->lifo = 1;
731         revs->dense = 1;
732         revs->prefix = prefix;
733         revs->max_age = -1;
734         revs->min_age = -1;
735         revs->skip_count = -1;
736         revs->max_count = -1;
737
738         revs->commit_format = CMIT_FMT_DEFAULT;
739
740         diff_setup(&revs->diffopt);
741 }
742
743 static void add_pending_commit_list(struct rev_info *revs,
744                                     struct commit_list *commit_list,
745                                     unsigned int flags)
746 {
747         while (commit_list) {
748                 struct object *object = &commit_list->item->object;
749                 object->flags |= flags;
750                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
751                 commit_list = commit_list->next;
752         }
753 }
754
755 static void prepare_show_merge(struct rev_info *revs)
756 {
757         struct commit_list *bases;
758         struct commit *head, *other;
759         unsigned char sha1[20];
760         const char **prune = NULL;
761         int i, prune_num = 1; /* counting terminating NULL */
762
763         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
764                 die("--merge without HEAD?");
765         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
766                 die("--merge without MERGE_HEAD?");
767         add_pending_object(revs, &head->object, "HEAD");
768         add_pending_object(revs, &other->object, "MERGE_HEAD");
769         bases = get_merge_bases(head, other, 1);
770         while (bases) {
771                 struct commit *it = bases->item;
772                 struct commit_list *n = bases->next;
773                 free(bases);
774                 bases = n;
775                 it->object.flags |= UNINTERESTING;
776                 add_pending_object(revs, &it->object, "(merge-base)");
777         }
778
779         if (!active_nr)
780                 read_cache();
781         for (i = 0; i < active_nr; i++) {
782                 struct cache_entry *ce = active_cache[i];
783                 if (!ce_stage(ce))
784                         continue;
785                 if (ce_path_match(ce, revs->prune_data)) {
786                         prune_num++;
787                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
788                         prune[prune_num-2] = ce->name;
789                         prune[prune_num-1] = NULL;
790                 }
791                 while ((i+1 < active_nr) &&
792                        ce_same_name(ce, active_cache[i+1]))
793                         i++;
794         }
795         revs->prune_data = prune;
796 }
797
798 int handle_revision_arg(const char *arg, struct rev_info *revs,
799                         int flags,
800                         int cant_be_filename)
801 {
802         unsigned mode;
803         char *dotdot;
804         struct object *object;
805         unsigned char sha1[20];
806         int local_flags;
807
808         dotdot = strstr(arg, "..");
809         if (dotdot) {
810                 unsigned char from_sha1[20];
811                 const char *next = dotdot + 2;
812                 const char *this = arg;
813                 int symmetric = *next == '.';
814                 unsigned int flags_exclude = flags ^ UNINTERESTING;
815
816                 *dotdot = 0;
817                 next += symmetric;
818
819                 if (!*next)
820                         next = "HEAD";
821                 if (dotdot == arg)
822                         this = "HEAD";
823                 if (!get_sha1(this, from_sha1) &&
824                     !get_sha1(next, sha1)) {
825                         struct commit *a, *b;
826                         struct commit_list *exclude;
827
828                         a = lookup_commit_reference(from_sha1);
829                         b = lookup_commit_reference(sha1);
830                         if (!a || !b) {
831                                 die(symmetric ?
832                                     "Invalid symmetric difference expression %s...%s" :
833                                     "Invalid revision range %s..%s",
834                                     arg, next);
835                         }
836
837                         if (!cant_be_filename) {
838                                 *dotdot = '.';
839                                 verify_non_filename(revs->prefix, arg);
840                         }
841
842                         if (symmetric) {
843                                 exclude = get_merge_bases(a, b, 1);
844                                 add_pending_commit_list(revs, exclude,
845                                                         flags_exclude);
846                                 free_commit_list(exclude);
847                                 a->object.flags |= flags | SYMMETRIC_LEFT;
848                         } else
849                                 a->object.flags |= flags_exclude;
850                         b->object.flags |= flags;
851                         add_pending_object(revs, &a->object, this);
852                         add_pending_object(revs, &b->object, next);
853                         return 0;
854                 }
855                 *dotdot = '.';
856         }
857         dotdot = strstr(arg, "^@");
858         if (dotdot && !dotdot[2]) {
859                 *dotdot = 0;
860                 if (add_parents_only(revs, arg, flags))
861                         return 0;
862                 *dotdot = '^';
863         }
864         dotdot = strstr(arg, "^!");
865         if (dotdot && !dotdot[2]) {
866                 *dotdot = 0;
867                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
868                         *dotdot = '^';
869         }
870
871         local_flags = 0;
872         if (*arg == '^') {
873                 local_flags = UNINTERESTING;
874                 arg++;
875         }
876         if (get_sha1_with_mode(arg, sha1, &mode))
877                 return -1;
878         if (!cant_be_filename)
879                 verify_non_filename(revs->prefix, arg);
880         object = get_reference(revs, arg, sha1, flags ^ local_flags);
881         add_pending_object_with_mode(revs, object, arg, mode);
882         return 0;
883 }
884
885 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
886 {
887         if (!revs->grep_filter) {
888                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
889                 opt->status_only = 1;
890                 opt->pattern_tail = &(opt->pattern_list);
891                 opt->regflags = REG_NEWLINE;
892                 revs->grep_filter = opt;
893         }
894         append_grep_pattern(revs->grep_filter, ptn,
895                             "command line", 0, what);
896 }
897
898 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
899 {
900         char *pat;
901         const char *prefix;
902         int patlen, fldlen;
903
904         fldlen = strlen(field);
905         patlen = strlen(pattern);
906         pat = xmalloc(patlen + fldlen + 10);
907         prefix = ".*";
908         if (*pattern == '^') {
909                 prefix = "";
910                 pattern++;
911         }
912         sprintf(pat, "^%s %s%s", field, prefix, pattern);
913         add_grep(revs, pat, GREP_PATTERN_HEAD);
914 }
915
916 static void add_message_grep(struct rev_info *revs, const char *pattern)
917 {
918         add_grep(revs, pattern, GREP_PATTERN_BODY);
919 }
920
921 static void add_ignore_packed(struct rev_info *revs, const char *name)
922 {
923         int num = ++revs->num_ignore_packed;
924
925         revs->ignore_packed = xrealloc(revs->ignore_packed,
926                                        sizeof(const char **) * (num + 1));
927         revs->ignore_packed[num-1] = name;
928         revs->ignore_packed[num] = NULL;
929 }
930
931 /*
932  * Parse revision information, filling in the "rev_info" structure,
933  * and removing the used arguments from the argument list.
934  *
935  * Returns the number of arguments left that weren't recognized
936  * (which are also moved to the head of the argument list)
937  */
938 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
939 {
940         int i, flags, seen_dashdash, show_merge;
941         const char **unrecognized = argv + 1;
942         int left = 1;
943         int all_match = 0;
944         int regflags = 0;
945
946         /* First, search for "--" */
947         seen_dashdash = 0;
948         for (i = 1; i < argc; i++) {
949                 const char *arg = argv[i];
950                 if (strcmp(arg, "--"))
951                         continue;
952                 argv[i] = NULL;
953                 argc = i;
954                 if (argv[i + 1])
955                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
956                 seen_dashdash = 1;
957                 break;
958         }
959
960         flags = show_merge = 0;
961         for (i = 1; i < argc; i++) {
962                 const char *arg = argv[i];
963                 if (*arg == '-') {
964                         int opts;
965                         if (!prefixcmp(arg, "--max-count=")) {
966                                 revs->max_count = atoi(arg + 12);
967                                 continue;
968                         }
969                         if (!prefixcmp(arg, "--skip=")) {
970                                 revs->skip_count = atoi(arg + 7);
971                                 continue;
972                         }
973                         /* accept -<digit>, like traditional "head" */
974                         if ((*arg == '-') && isdigit(arg[1])) {
975                                 revs->max_count = atoi(arg + 1);
976                                 continue;
977                         }
978                         if (!strcmp(arg, "-n")) {
979                                 if (argc <= i + 1)
980                                         die("-n requires an argument");
981                                 revs->max_count = atoi(argv[++i]);
982                                 continue;
983                         }
984                         if (!prefixcmp(arg, "-n")) {
985                                 revs->max_count = atoi(arg + 2);
986                                 continue;
987                         }
988                         if (!prefixcmp(arg, "--max-age=")) {
989                                 revs->max_age = atoi(arg + 10);
990                                 continue;
991                         }
992                         if (!prefixcmp(arg, "--since=")) {
993                                 revs->max_age = approxidate(arg + 8);
994                                 continue;
995                         }
996                         if (!prefixcmp(arg, "--after=")) {
997                                 revs->max_age = approxidate(arg + 8);
998                                 continue;
999                         }
1000                         if (!prefixcmp(arg, "--min-age=")) {
1001                                 revs->min_age = atoi(arg + 10);
1002                                 continue;
1003                         }
1004                         if (!prefixcmp(arg, "--before=")) {
1005                                 revs->min_age = approxidate(arg + 9);
1006                                 continue;
1007                         }
1008                         if (!prefixcmp(arg, "--until=")) {
1009                                 revs->min_age = approxidate(arg + 8);
1010                                 continue;
1011                         }
1012                         if (!strcmp(arg, "--all")) {
1013                                 handle_all(revs, flags);
1014                                 continue;
1015                         }
1016                         if (!strcmp(arg, "--first-parent")) {
1017                                 revs->first_parent_only = 1;
1018                                 continue;
1019                         }
1020                         if (!strcmp(arg, "--reflog")) {
1021                                 handle_reflog(revs, flags);
1022                                 continue;
1023                         }
1024                         if (!strcmp(arg, "-g") ||
1025                                         !strcmp(arg, "--walk-reflogs")) {
1026                                 init_reflog_walk(&revs->reflog_info);
1027                                 continue;
1028                         }
1029                         if (!strcmp(arg, "--not")) {
1030                                 flags ^= UNINTERESTING;
1031                                 continue;
1032                         }
1033                         if (!strcmp(arg, "--default")) {
1034                                 if (++i >= argc)
1035                                         die("bad --default argument");
1036                                 def = argv[i];
1037                                 continue;
1038                         }
1039                         if (!strcmp(arg, "--merge")) {
1040                                 show_merge = 1;
1041                                 continue;
1042                         }
1043                         if (!strcmp(arg, "--topo-order")) {
1044                                 revs->topo_order = 1;
1045                                 continue;
1046                         }
1047                         if (!strcmp(arg, "--date-order")) {
1048                                 revs->lifo = 0;
1049                                 revs->topo_order = 1;
1050                                 continue;
1051                         }
1052                         if (!prefixcmp(arg, "--early-output")) {
1053                                 int count = 100;
1054                                 switch (arg[14]) {
1055                                 case '=':
1056                                         count = atoi(arg+15);
1057                                         /* Fallthrough */
1058                                 case 0:
1059                                         revs->topo_order = 1;
1060                                         revs->early_output = count;
1061                                         continue;
1062                                 }
1063                         }
1064                         if (!strcmp(arg, "--parents")) {
1065                                 revs->parents = 1;
1066                                 continue;
1067                         }
1068                         if (!strcmp(arg, "--dense")) {
1069                                 revs->dense = 1;
1070                                 continue;
1071                         }
1072                         if (!strcmp(arg, "--sparse")) {
1073                                 revs->dense = 0;
1074                                 continue;
1075                         }
1076                         if (!strcmp(arg, "--show-all")) {
1077                                 revs->show_all = 1;
1078                                 continue;
1079                         }
1080                         if (!strcmp(arg, "--remove-empty")) {
1081                                 revs->remove_empty_trees = 1;
1082                                 continue;
1083                         }
1084                         if (!strcmp(arg, "--no-merges")) {
1085                                 revs->no_merges = 1;
1086                                 continue;
1087                         }
1088                         if (!strcmp(arg, "--boundary")) {
1089                                 revs->boundary = 1;
1090                                 continue;
1091                         }
1092                         if (!strcmp(arg, "--left-right")) {
1093                                 revs->left_right = 1;
1094                                 continue;
1095                         }
1096                         if (!strcmp(arg, "--cherry-pick")) {
1097                                 revs->cherry_pick = 1;
1098                                 revs->limited = 1;
1099                                 continue;
1100                         }
1101                         if (!strcmp(arg, "--objects")) {
1102                                 revs->tag_objects = 1;
1103                                 revs->tree_objects = 1;
1104                                 revs->blob_objects = 1;
1105                                 continue;
1106                         }
1107                         if (!strcmp(arg, "--objects-edge")) {
1108                                 revs->tag_objects = 1;
1109                                 revs->tree_objects = 1;
1110                                 revs->blob_objects = 1;
1111                                 revs->edge_hint = 1;
1112                                 continue;
1113                         }
1114                         if (!strcmp(arg, "--unpacked")) {
1115                                 revs->unpacked = 1;
1116                                 free(revs->ignore_packed);
1117                                 revs->ignore_packed = NULL;
1118                                 revs->num_ignore_packed = 0;
1119                                 continue;
1120                         }
1121                         if (!prefixcmp(arg, "--unpacked=")) {
1122                                 revs->unpacked = 1;
1123                                 add_ignore_packed(revs, arg+11);
1124                                 continue;
1125                         }
1126                         if (!strcmp(arg, "-r")) {
1127                                 revs->diff = 1;
1128                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1129                                 continue;
1130                         }
1131                         if (!strcmp(arg, "-t")) {
1132                                 revs->diff = 1;
1133                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1134                                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1135                                 continue;
1136                         }
1137                         if (!strcmp(arg, "-m")) {
1138                                 revs->ignore_merges = 0;
1139                                 continue;
1140                         }
1141                         if (!strcmp(arg, "-c")) {
1142                                 revs->diff = 1;
1143                                 revs->dense_combined_merges = 0;
1144                                 revs->combine_merges = 1;
1145                                 continue;
1146                         }
1147                         if (!strcmp(arg, "--cc")) {
1148                                 revs->diff = 1;
1149                                 revs->dense_combined_merges = 1;
1150                                 revs->combine_merges = 1;
1151                                 continue;
1152                         }
1153                         if (!strcmp(arg, "-v")) {
1154                                 revs->verbose_header = 1;
1155                                 continue;
1156                         }
1157                         if (!prefixcmp(arg, "--pretty")) {
1158                                 revs->verbose_header = 1;
1159                                 revs->commit_format = get_commit_format(arg+8);
1160                                 continue;
1161                         }
1162                         if (!strcmp(arg, "--root")) {
1163                                 revs->show_root_diff = 1;
1164                                 continue;
1165                         }
1166                         if (!strcmp(arg, "--no-commit-id")) {
1167                                 revs->no_commit_id = 1;
1168                                 continue;
1169                         }
1170                         if (!strcmp(arg, "--always")) {
1171                                 revs->always_show_header = 1;
1172                                 continue;
1173                         }
1174                         if (!strcmp(arg, "--no-abbrev")) {
1175                                 revs->abbrev = 0;
1176                                 continue;
1177                         }
1178                         if (!strcmp(arg, "--abbrev")) {
1179                                 revs->abbrev = DEFAULT_ABBREV;
1180                                 continue;
1181                         }
1182                         if (!prefixcmp(arg, "--abbrev=")) {
1183                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1184                                 if (revs->abbrev < MINIMUM_ABBREV)
1185                                         revs->abbrev = MINIMUM_ABBREV;
1186                                 else if (revs->abbrev > 40)
1187                                         revs->abbrev = 40;
1188                                 continue;
1189                         }
1190                         if (!strcmp(arg, "--abbrev-commit")) {
1191                                 revs->abbrev_commit = 1;
1192                                 continue;
1193                         }
1194                         if (!strcmp(arg, "--full-diff")) {
1195                                 revs->diff = 1;
1196                                 revs->full_diff = 1;
1197                                 continue;
1198                         }
1199                         if (!strcmp(arg, "--full-history")) {
1200                                 revs->simplify_history = 0;
1201                                 continue;
1202                         }
1203                         if (!strcmp(arg, "--relative-date")) {
1204                                 revs->date_mode = DATE_RELATIVE;
1205                                 continue;
1206                         }
1207                         if (!strncmp(arg, "--date=", 7)) {
1208                                 revs->date_mode = parse_date_format(arg + 7);
1209                                 continue;
1210                         }
1211                         if (!strcmp(arg, "--log-size")) {
1212                                 revs->show_log_size = 1;
1213                                 continue;
1214                         }
1215
1216                         /*
1217                          * Grepping the commit log
1218                          */
1219                         if (!prefixcmp(arg, "--author=")) {
1220                                 add_header_grep(revs, "author", arg+9);
1221                                 continue;
1222                         }
1223                         if (!prefixcmp(arg, "--committer=")) {
1224                                 add_header_grep(revs, "committer", arg+12);
1225                                 continue;
1226                         }
1227                         if (!prefixcmp(arg, "--grep=")) {
1228                                 add_message_grep(revs, arg+7);
1229                                 continue;
1230                         }
1231                         if (!strcmp(arg, "--extended-regexp") ||
1232                             !strcmp(arg, "-E")) {
1233                                 regflags |= REG_EXTENDED;
1234                                 continue;
1235                         }
1236                         if (!strcmp(arg, "--regexp-ignore-case") ||
1237                             !strcmp(arg, "-i")) {
1238                                 regflags |= REG_ICASE;
1239                                 continue;
1240                         }
1241                         if (!strcmp(arg, "--all-match")) {
1242                                 all_match = 1;
1243                                 continue;
1244                         }
1245                         if (!prefixcmp(arg, "--encoding=")) {
1246                                 arg += 11;
1247                                 if (strcmp(arg, "none"))
1248                                         git_log_output_encoding = xstrdup(arg);
1249                                 else
1250                                         git_log_output_encoding = "";
1251                                 continue;
1252                         }
1253                         if (!strcmp(arg, "--reverse")) {
1254                                 revs->reverse ^= 1;
1255                                 continue;
1256                         }
1257                         if (!strcmp(arg, "--no-walk")) {
1258                                 revs->no_walk = 1;
1259                                 continue;
1260                         }
1261                         if (!strcmp(arg, "--do-walk")) {
1262                                 revs->no_walk = 0;
1263                                 continue;
1264                         }
1265
1266                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
1267                         if (opts > 0) {
1268                                 i += opts - 1;
1269                                 continue;
1270                         }
1271                         *unrecognized++ = arg;
1272                         left++;
1273                         continue;
1274                 }
1275
1276                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1277                         int j;
1278                         if (seen_dashdash || *arg == '^')
1279                                 die("bad revision '%s'", arg);
1280
1281                         /* If we didn't have a "--":
1282                          * (1) all filenames must exist;
1283                          * (2) all rev-args must not be interpretable
1284                          *     as a valid filename.
1285                          * but the latter we have checked in the main loop.
1286                          */
1287                         for (j = i; j < argc; j++)
1288                                 verify_filename(revs->prefix, argv[j]);
1289
1290                         revs->prune_data = get_pathspec(revs->prefix,
1291                                                         argv + i);
1292                         break;
1293                 }
1294         }
1295
1296         if (revs->grep_filter)
1297                 revs->grep_filter->regflags |= regflags;
1298
1299         if (show_merge)
1300                 prepare_show_merge(revs);
1301         if (def && !revs->pending.nr) {
1302                 unsigned char sha1[20];
1303                 struct object *object;
1304                 unsigned mode;
1305                 if (get_sha1_with_mode(def, sha1, &mode))
1306                         die("bad default revision '%s'", def);
1307                 object = get_reference(revs, def, sha1, 0);
1308                 add_pending_object_with_mode(revs, object, def, mode);
1309         }
1310
1311         /* Did the user ask for any diff output? Run the diff! */
1312         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1313                 revs->diff = 1;
1314
1315         /* Pickaxe, diff-filter and rename following need diffs */
1316         if (revs->diffopt.pickaxe ||
1317             revs->diffopt.filter ||
1318             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1319                 revs->diff = 1;
1320
1321         if (revs->topo_order)
1322                 revs->limited = 1;
1323
1324         if (revs->prune_data) {
1325                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1326                 /* Can't prune commits with rename following: the paths change.. */
1327                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1328                         revs->prune = 1;
1329                 if (!revs->full_diff)
1330                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1331         }
1332         if (revs->combine_merges) {
1333                 revs->ignore_merges = 0;
1334                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1335                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1336         }
1337         revs->diffopt.abbrev = revs->abbrev;
1338         if (diff_setup_done(&revs->diffopt) < 0)
1339                 die("diff_setup_done failed");
1340
1341         if (revs->grep_filter) {
1342                 revs->grep_filter->all_match = all_match;
1343                 compile_grep_patterns(revs->grep_filter);
1344         }
1345
1346         if (revs->reverse && revs->reflog_info)
1347                 die("cannot combine --reverse with --walk-reflogs");
1348
1349         return left;
1350 }
1351
1352 int prepare_revision_walk(struct rev_info *revs)
1353 {
1354         int nr = revs->pending.nr;
1355         struct object_array_entry *e, *list;
1356
1357         e = list = revs->pending.objects;
1358         revs->pending.nr = 0;
1359         revs->pending.alloc = 0;
1360         revs->pending.objects = NULL;
1361         while (--nr >= 0) {
1362                 struct commit *commit = handle_commit(revs, e->item, e->name);
1363                 if (commit) {
1364                         if (!(commit->object.flags & SEEN)) {
1365                                 commit->object.flags |= SEEN;
1366                                 insert_by_date(commit, &revs->commits);
1367                         }
1368                 }
1369                 e++;
1370         }
1371         free(list);
1372
1373         if (revs->no_walk)
1374                 return 0;
1375         if (revs->limited)
1376                 if (limit_list(revs) < 0)
1377                         return -1;
1378         if (revs->topo_order)
1379                 sort_in_topological_order(&revs->commits, revs->lifo);
1380         return 0;
1381 }
1382
1383 enum rewrite_result {
1384         rewrite_one_ok,
1385         rewrite_one_noparents,
1386         rewrite_one_error,
1387 };
1388
1389 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1390 {
1391         for (;;) {
1392                 struct commit *p = *pp;
1393                 if (!revs->limited)
1394                         if (add_parents_to_list(revs, p, &revs->commits) < 0)
1395                                 return rewrite_one_error;
1396                 if (p->parents && p->parents->next)
1397                         return rewrite_one_ok;
1398                 if (p->object.flags & UNINTERESTING)
1399                         return rewrite_one_ok;
1400                 if (!(p->object.flags & TREESAME))
1401                         return rewrite_one_ok;
1402                 if (!p->parents)
1403                         return rewrite_one_noparents;
1404                 *pp = p->parents->item;
1405         }
1406 }
1407
1408 static void remove_duplicate_parents(struct commit *commit)
1409 {
1410         struct commit_list **pp, *p;
1411
1412         /* Examine existing parents while marking ones we have seen... */
1413         pp = &commit->parents;
1414         while ((p = *pp) != NULL) {
1415                 struct commit *parent = p->item;
1416                 if (parent->object.flags & TMP_MARK) {
1417                         *pp = p->next;
1418                         continue;
1419                 }
1420                 parent->object.flags |= TMP_MARK;
1421                 pp = &p->next;
1422         }
1423         /* ... and clear the temporary mark */
1424         for (p = commit->parents; p; p = p->next)
1425                 p->item->object.flags &= ~TMP_MARK;
1426 }
1427
1428 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1429 {
1430         struct commit_list **pp = &commit->parents;
1431         while (*pp) {
1432                 struct commit_list *parent = *pp;
1433                 switch (rewrite_one(revs, &parent->item)) {
1434                 case rewrite_one_ok:
1435                         break;
1436                 case rewrite_one_noparents:
1437                         *pp = parent->next;
1438                         continue;
1439                 case rewrite_one_error:
1440                         return -1;
1441                 }
1442                 pp = &parent->next;
1443         }
1444         remove_duplicate_parents(commit);
1445         return 0;
1446 }
1447
1448 static int commit_match(struct commit *commit, struct rev_info *opt)
1449 {
1450         if (!opt->grep_filter)
1451                 return 1;
1452         return grep_buffer(opt->grep_filter,
1453                            NULL, /* we say nothing, not even filename */
1454                            commit->buffer, strlen(commit->buffer));
1455 }
1456
1457 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1458 {
1459         if (commit->object.flags & SHOWN)
1460                 return commit_ignore;
1461         if (revs->unpacked && has_sha1_pack(commit->object.sha1, revs->ignore_packed))
1462                 return commit_ignore;
1463         if (revs->show_all)
1464                 return commit_show;
1465         if (commit->object.flags & UNINTERESTING)
1466                 return commit_ignore;
1467         if (revs->min_age != -1 && (commit->date > revs->min_age))
1468                 return commit_ignore;
1469         if (revs->no_merges && commit->parents && commit->parents->next)
1470                 return commit_ignore;
1471         if (!commit_match(commit, revs))
1472                 return commit_ignore;
1473         if (revs->prune && revs->dense) {
1474                 /* Commit without changes? */
1475                 if (commit->object.flags & TREESAME) {
1476                         /* drop merges unless we want parenthood */
1477                         if (!revs->parents)
1478                                 return commit_ignore;
1479                         /* non-merge - always ignore it */
1480                         if (!commit->parents || !commit->parents->next)
1481                                 return commit_ignore;
1482                 }
1483                 if (revs->parents && rewrite_parents(revs, commit) < 0)
1484                         return commit_error;
1485         }
1486         return commit_show;
1487 }
1488
1489 static struct commit *get_revision_1(struct rev_info *revs)
1490 {
1491         if (!revs->commits)
1492                 return NULL;
1493
1494         do {
1495                 struct commit_list *entry = revs->commits;
1496                 struct commit *commit = entry->item;
1497
1498                 revs->commits = entry->next;
1499                 free(entry);
1500
1501                 if (revs->reflog_info)
1502                         fake_reflog_parent(revs->reflog_info, commit);
1503
1504                 /*
1505                  * If we haven't done the list limiting, we need to look at
1506                  * the parents here. We also need to do the date-based limiting
1507                  * that we'd otherwise have done in limit_list().
1508                  */
1509                 if (!revs->limited) {
1510                         if (revs->max_age != -1 &&
1511                             (commit->date < revs->max_age))
1512                                 continue;
1513                         if (add_parents_to_list(revs, commit, &revs->commits) < 0)
1514                                 return NULL;
1515                 }
1516
1517                 switch (simplify_commit(revs, commit)) {
1518                 case commit_ignore:
1519                         continue;
1520                 case commit_error:
1521                         return NULL;
1522                 default:
1523                         return commit;
1524                 }
1525         } while (revs->commits);
1526         return NULL;
1527 }
1528
1529 static void gc_boundary(struct object_array *array)
1530 {
1531         unsigned nr = array->nr;
1532         unsigned alloc = array->alloc;
1533         struct object_array_entry *objects = array->objects;
1534
1535         if (alloc <= nr) {
1536                 unsigned i, j;
1537                 for (i = j = 0; i < nr; i++) {
1538                         if (objects[i].item->flags & SHOWN)
1539                                 continue;
1540                         if (i != j)
1541                                 objects[j] = objects[i];
1542                         j++;
1543                 }
1544                 for (i = j; i < nr; i++)
1545                         objects[i].item = NULL;
1546                 array->nr = j;
1547         }
1548 }
1549
1550 struct commit *get_revision(struct rev_info *revs)
1551 {
1552         struct commit *c = NULL;
1553         struct commit_list *l;
1554
1555         if (revs->boundary == 2) {
1556                 unsigned i;
1557                 struct object_array *array = &revs->boundary_commits;
1558                 struct object_array_entry *objects = array->objects;
1559                 for (i = 0; i < array->nr; i++) {
1560                         c = (struct commit *)(objects[i].item);
1561                         if (!c)
1562                                 continue;
1563                         if (!(c->object.flags & CHILD_SHOWN))
1564                                 continue;
1565                         if (!(c->object.flags & SHOWN))
1566                                 break;
1567                 }
1568                 if (array->nr <= i)
1569                         return NULL;
1570
1571                 c->object.flags |= SHOWN | BOUNDARY;
1572                 return c;
1573         }
1574
1575         if (revs->reverse) {
1576                 int limit = -1;
1577
1578                 if (0 <= revs->max_count) {
1579                         limit = revs->max_count;
1580                         if (0 < revs->skip_count)
1581                                 limit += revs->skip_count;
1582                 }
1583                 l = NULL;
1584                 while ((c = get_revision_1(revs))) {
1585                         commit_list_insert(c, &l);
1586                         if ((0 < limit) && !--limit)
1587                                 break;
1588                 }
1589                 revs->commits = l;
1590                 revs->reverse = 0;
1591                 revs->max_count = -1;
1592                 c = NULL;
1593         }
1594
1595         /*
1596          * Now pick up what they want to give us
1597          */
1598         c = get_revision_1(revs);
1599         if (c) {
1600                 while (0 < revs->skip_count) {
1601                         revs->skip_count--;
1602                         c = get_revision_1(revs);
1603                         if (!c)
1604                                 break;
1605                 }
1606         }
1607
1608         /*
1609          * Check the max_count.
1610          */
1611         switch (revs->max_count) {
1612         case -1:
1613                 break;
1614         case 0:
1615                 c = NULL;
1616                 break;
1617         default:
1618                 revs->max_count--;
1619         }
1620
1621         if (c)
1622                 c->object.flags |= SHOWN;
1623
1624         if (!revs->boundary) {
1625                 return c;
1626         }
1627
1628         if (!c) {
1629                 /*
1630                  * get_revision_1() runs out the commits, and
1631                  * we are done computing the boundaries.
1632                  * switch to boundary commits output mode.
1633                  */
1634                 revs->boundary = 2;
1635                 return get_revision(revs);
1636         }
1637
1638         /*
1639          * boundary commits are the commits that are parents of the
1640          * ones we got from get_revision_1() but they themselves are
1641          * not returned from get_revision_1().  Before returning
1642          * 'c', we need to mark its parents that they could be boundaries.
1643          */
1644
1645         for (l = c->parents; l; l = l->next) {
1646                 struct object *p;
1647                 p = &(l->item->object);
1648                 if (p->flags & (CHILD_SHOWN | SHOWN))
1649                         continue;
1650                 p->flags |= CHILD_SHOWN;
1651                 gc_boundary(&revs->boundary_commits);
1652                 add_object_array(p, NULL, &revs->boundary_commits);
1653         }
1654
1655         return c;
1656 }