rev-list: --left/right-only are mutually exclusive
[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 "graph.h"
10 #include "grep.h"
11 #include "reflog-walk.h"
12 #include "patch-ids.h"
13 #include "decorate.h"
14 #include "log-tree.h"
15 #include "string-list.h"
16
17 volatile show_early_output_fn_t show_early_output;
18
19 char *path_name(const struct name_path *path, const char *name)
20 {
21         const struct name_path *p;
22         char *n, *m;
23         int nlen = strlen(name);
24         int len = nlen + 1;
25
26         for (p = path; p; p = p->up) {
27                 if (p->elem_len)
28                         len += p->elem_len + 1;
29         }
30         n = xmalloc(len);
31         m = n + len - (nlen + 1);
32         strcpy(m, name);
33         for (p = path; p; p = p->up) {
34                 if (p->elem_len) {
35                         m -= p->elem_len + 1;
36                         memcpy(m, p->elem, p->elem_len);
37                         m[p->elem_len] = '/';
38                 }
39         }
40         return n;
41 }
42
43 void add_object(struct object *obj,
44                 struct object_array *p,
45                 struct name_path *path,
46                 const char *name)
47 {
48         add_object_array(obj, path_name(path, name), p);
49 }
50
51 static void mark_blob_uninteresting(struct blob *blob)
52 {
53         if (!blob)
54                 return;
55         if (blob->object.flags & UNINTERESTING)
56                 return;
57         blob->object.flags |= UNINTERESTING;
58 }
59
60 void mark_tree_uninteresting(struct tree *tree)
61 {
62         struct tree_desc desc;
63         struct name_entry entry;
64         struct object *obj = &tree->object;
65
66         if (!tree)
67                 return;
68         if (obj->flags & UNINTERESTING)
69                 return;
70         obj->flags |= UNINTERESTING;
71         if (!has_sha1_file(obj->sha1))
72                 return;
73         if (parse_tree(tree) < 0)
74                 die("bad tree %s", sha1_to_hex(obj->sha1));
75
76         init_tree_desc(&desc, tree->buffer, tree->size);
77         while (tree_entry(&desc, &entry)) {
78                 switch (object_type(entry.mode)) {
79                 case OBJ_TREE:
80                         mark_tree_uninteresting(lookup_tree(entry.sha1));
81                         break;
82                 case OBJ_BLOB:
83                         mark_blob_uninteresting(lookup_blob(entry.sha1));
84                         break;
85                 default:
86                         /* Subproject commit - not in this repository */
87                         break;
88                 }
89         }
90
91         /*
92          * We don't care about the tree any more
93          * after it has been marked uninteresting.
94          */
95         free(tree->buffer);
96         tree->buffer = NULL;
97 }
98
99 void mark_parents_uninteresting(struct commit *commit)
100 {
101         struct commit_list *parents = commit->parents;
102
103         while (parents) {
104                 struct commit *commit = parents->item;
105                 if (!(commit->object.flags & UNINTERESTING)) {
106                         commit->object.flags |= UNINTERESTING;
107
108                         /*
109                          * Normally we haven't parsed the parent
110                          * yet, so we won't have a parent of a parent
111                          * here. However, it may turn out that we've
112                          * reached this commit some other way (where it
113                          * wasn't uninteresting), in which case we need
114                          * to mark its parents recursively too..
115                          */
116                         if (commit->parents)
117                                 mark_parents_uninteresting(commit);
118                 }
119
120                 /*
121                  * A missing commit is ok iff its parent is marked
122                  * uninteresting.
123                  *
124                  * We just mark such a thing parsed, so that when
125                  * it is popped next time around, we won't be trying
126                  * to parse it and get an error.
127                  */
128                 if (!has_sha1_file(commit->object.sha1))
129                         commit->object.parsed = 1;
130                 parents = parents->next;
131         }
132 }
133
134 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
135 {
136         if (revs->no_walk && (obj->flags & UNINTERESTING))
137                 revs->no_walk = 0;
138         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
139                 struct strbuf buf = STRBUF_INIT;
140                 int len = interpret_branch_name(name, &buf);
141                 int st;
142
143                 if (0 < len && name[len] && buf.len)
144                         strbuf_addstr(&buf, name + len);
145                 st = add_reflog_for_walk(revs->reflog_info,
146                                          (struct commit *)obj,
147                                          buf.buf[0] ? buf.buf: name);
148                 strbuf_release(&buf);
149                 if (st)
150                         return;
151         }
152         add_object_array_with_mode(obj, name, &revs->pending, mode);
153 }
154
155 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
156 {
157         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
158 }
159
160 void add_head_to_pending(struct rev_info *revs)
161 {
162         unsigned char sha1[20];
163         struct object *obj;
164         if (get_sha1("HEAD", sha1))
165                 return;
166         obj = parse_object(sha1);
167         if (!obj)
168                 return;
169         add_pending_object(revs, obj, "HEAD");
170 }
171
172 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
173 {
174         struct object *object;
175
176         object = parse_object(sha1);
177         if (!object)
178                 die("bad object %s", name);
179         object->flags |= flags;
180         return object;
181 }
182
183 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
184 {
185         unsigned long flags = object->flags;
186
187         /*
188          * Tag object? Look what it points to..
189          */
190         while (object->type == OBJ_TAG) {
191                 struct tag *tag = (struct tag *) object;
192                 if (revs->tag_objects && !(flags & UNINTERESTING))
193                         add_pending_object(revs, object, tag->tag);
194                 if (!tag->tagged)
195                         die("bad tag");
196                 object = parse_object(tag->tagged->sha1);
197                 if (!object) {
198                         if (flags & UNINTERESTING)
199                                 return NULL;
200                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
201                 }
202         }
203
204         /*
205          * Commit object? Just return it, we'll do all the complex
206          * reachability crud.
207          */
208         if (object->type == OBJ_COMMIT) {
209                 struct commit *commit = (struct commit *)object;
210                 if (parse_commit(commit) < 0)
211                         die("unable to parse commit %s", name);
212                 if (flags & UNINTERESTING) {
213                         commit->object.flags |= UNINTERESTING;
214                         mark_parents_uninteresting(commit);
215                         revs->limited = 1;
216                 }
217                 if (revs->show_source && !commit->util)
218                         commit->util = (void *) name;
219                 return commit;
220         }
221
222         /*
223          * Tree object? Either mark it uninteresting, or add it
224          * to the list of objects to look at later..
225          */
226         if (object->type == OBJ_TREE) {
227                 struct tree *tree = (struct tree *)object;
228                 if (!revs->tree_objects)
229                         return NULL;
230                 if (flags & UNINTERESTING) {
231                         mark_tree_uninteresting(tree);
232                         return NULL;
233                 }
234                 add_pending_object(revs, object, "");
235                 return NULL;
236         }
237
238         /*
239          * Blob object? You know the drill by now..
240          */
241         if (object->type == OBJ_BLOB) {
242                 struct blob *blob = (struct blob *)object;
243                 if (!revs->blob_objects)
244                         return NULL;
245                 if (flags & UNINTERESTING) {
246                         mark_blob_uninteresting(blob);
247                         return NULL;
248                 }
249                 add_pending_object(revs, object, "");
250                 return NULL;
251         }
252         die("%s is unknown object", name);
253 }
254
255 static int everybody_uninteresting(struct commit_list *orig)
256 {
257         struct commit_list *list = orig;
258         while (list) {
259                 struct commit *commit = list->item;
260                 list = list->next;
261                 if (commit->object.flags & UNINTERESTING)
262                         continue;
263                 return 0;
264         }
265         return 1;
266 }
267
268 /*
269  * The goal is to get REV_TREE_NEW as the result only if the
270  * diff consists of all '+' (and no other changes), REV_TREE_OLD
271  * if the whole diff is removal of old data, and otherwise
272  * REV_TREE_DIFFERENT (of course if the trees are the same we
273  * want REV_TREE_SAME).
274  * That means that once we get to REV_TREE_DIFFERENT, we do not
275  * have to look any further.
276  */
277 static int tree_difference = REV_TREE_SAME;
278
279 static void file_add_remove(struct diff_options *options,
280                     int addremove, unsigned mode,
281                     const unsigned char *sha1,
282                     const char *fullpath, unsigned dirty_submodule)
283 {
284         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
285
286         tree_difference |= diff;
287         if (tree_difference == REV_TREE_DIFFERENT)
288                 DIFF_OPT_SET(options, HAS_CHANGES);
289 }
290
291 static void file_change(struct diff_options *options,
292                  unsigned old_mode, unsigned new_mode,
293                  const unsigned char *old_sha1,
294                  const unsigned char *new_sha1,
295                  const char *fullpath,
296                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
297 {
298         tree_difference = REV_TREE_DIFFERENT;
299         DIFF_OPT_SET(options, HAS_CHANGES);
300 }
301
302 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
303 {
304         struct tree *t1 = parent->tree;
305         struct tree *t2 = commit->tree;
306
307         if (!t1)
308                 return REV_TREE_NEW;
309         if (!t2)
310                 return REV_TREE_OLD;
311
312         if (revs->simplify_by_decoration) {
313                 /*
314                  * If we are simplifying by decoration, then the commit
315                  * is worth showing if it has a tag pointing at it.
316                  */
317                 if (lookup_decoration(&name_decoration, &commit->object))
318                         return REV_TREE_DIFFERENT;
319                 /*
320                  * A commit that is not pointed by a tag is uninteresting
321                  * if we are not limited by path.  This means that you will
322                  * see the usual "commits that touch the paths" plus any
323                  * tagged commit by specifying both --simplify-by-decoration
324                  * and pathspec.
325                  */
326                 if (!revs->prune_data)
327                         return REV_TREE_SAME;
328         }
329
330         tree_difference = REV_TREE_SAME;
331         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
332         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
333                            &revs->pruning) < 0)
334                 return REV_TREE_DIFFERENT;
335         return tree_difference;
336 }
337
338 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
339 {
340         int retval;
341         void *tree;
342         unsigned long size;
343         struct tree_desc empty, real;
344         struct tree *t1 = commit->tree;
345
346         if (!t1)
347                 return 0;
348
349         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
350         if (!tree)
351                 return 0;
352         init_tree_desc(&real, tree, size);
353         init_tree_desc(&empty, "", 0);
354
355         tree_difference = REV_TREE_SAME;
356         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
357         retval = diff_tree(&empty, &real, "", &revs->pruning);
358         free(tree);
359
360         return retval >= 0 && (tree_difference == REV_TREE_SAME);
361 }
362
363 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
364 {
365         struct commit_list **pp, *parent;
366         int tree_changed = 0, tree_same = 0;
367
368         /*
369          * If we don't do pruning, everything is interesting
370          */
371         if (!revs->prune)
372                 return;
373
374         if (!commit->tree)
375                 return;
376
377         if (!commit->parents) {
378                 if (rev_same_tree_as_empty(revs, commit))
379                         commit->object.flags |= TREESAME;
380                 return;
381         }
382
383         /*
384          * Normal non-merge commit? If we don't want to make the
385          * history dense, we consider it always to be a change..
386          */
387         if (!revs->dense && !commit->parents->next)
388                 return;
389
390         pp = &commit->parents;
391         while ((parent = *pp) != NULL) {
392                 struct commit *p = parent->item;
393
394                 if (parse_commit(p) < 0)
395                         die("cannot simplify commit %s (because of %s)",
396                             sha1_to_hex(commit->object.sha1),
397                             sha1_to_hex(p->object.sha1));
398                 switch (rev_compare_tree(revs, p, commit)) {
399                 case REV_TREE_SAME:
400                         tree_same = 1;
401                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
402                                 /* Even if a merge with an uninteresting
403                                  * side branch brought the entire change
404                                  * we are interested in, we do not want
405                                  * to lose the other branches of this
406                                  * merge, so we just keep going.
407                                  */
408                                 pp = &parent->next;
409                                 continue;
410                         }
411                         parent->next = NULL;
412                         commit->parents = parent;
413                         commit->object.flags |= TREESAME;
414                         return;
415
416                 case REV_TREE_NEW:
417                         if (revs->remove_empty_trees &&
418                             rev_same_tree_as_empty(revs, p)) {
419                                 /* We are adding all the specified
420                                  * paths from this parent, so the
421                                  * history beyond this parent is not
422                                  * interesting.  Remove its parents
423                                  * (they are grandparents for us).
424                                  * IOW, we pretend this parent is a
425                                  * "root" commit.
426                                  */
427                                 if (parse_commit(p) < 0)
428                                         die("cannot simplify commit %s (invalid %s)",
429                                             sha1_to_hex(commit->object.sha1),
430                                             sha1_to_hex(p->object.sha1));
431                                 p->parents = NULL;
432                         }
433                 /* fallthrough */
434                 case REV_TREE_OLD:
435                 case REV_TREE_DIFFERENT:
436                         tree_changed = 1;
437                         pp = &parent->next;
438                         continue;
439                 }
440                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
441         }
442         if (tree_changed && !tree_same)
443                 return;
444         commit->object.flags |= TREESAME;
445 }
446
447 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
448                     struct commit_list *cached_base, struct commit_list **cache)
449 {
450         struct commit_list *new_entry;
451
452         if (cached_base && p->date < cached_base->item->date)
453                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
454         else
455                 new_entry = commit_list_insert_by_date(p, head);
456
457         if (cache && (!*cache || p->date < (*cache)->item->date))
458                 *cache = new_entry;
459 }
460
461 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
462                     struct commit_list **list, struct commit_list **cache_ptr)
463 {
464         struct commit_list *parent = commit->parents;
465         unsigned left_flag;
466         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
467
468         if (commit->object.flags & ADDED)
469                 return 0;
470         commit->object.flags |= ADDED;
471
472         /*
473          * If the commit is uninteresting, don't try to
474          * prune parents - we want the maximal uninteresting
475          * set.
476          *
477          * Normally we haven't parsed the parent
478          * yet, so we won't have a parent of a parent
479          * here. However, it may turn out that we've
480          * reached this commit some other way (where it
481          * wasn't uninteresting), in which case we need
482          * to mark its parents recursively too..
483          */
484         if (commit->object.flags & UNINTERESTING) {
485                 while (parent) {
486                         struct commit *p = parent->item;
487                         parent = parent->next;
488                         if (p)
489                                 p->object.flags |= UNINTERESTING;
490                         if (parse_commit(p) < 0)
491                                 continue;
492                         if (p->parents)
493                                 mark_parents_uninteresting(p);
494                         if (p->object.flags & SEEN)
495                                 continue;
496                         p->object.flags |= SEEN;
497                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
498                 }
499                 return 0;
500         }
501
502         /*
503          * Ok, the commit wasn't uninteresting. Try to
504          * simplify the commit history and find the parent
505          * that has no differences in the path set if one exists.
506          */
507         try_to_simplify_commit(revs, commit);
508
509         if (revs->no_walk)
510                 return 0;
511
512         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
513
514         for (parent = commit->parents; parent; parent = parent->next) {
515                 struct commit *p = parent->item;
516
517                 if (parse_commit(p) < 0)
518                         return -1;
519                 if (revs->show_source && !p->util)
520                         p->util = commit->util;
521                 p->object.flags |= left_flag;
522                 if (!(p->object.flags & SEEN)) {
523                         p->object.flags |= SEEN;
524                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
525                 }
526                 if (revs->first_parent_only)
527                         break;
528         }
529         return 0;
530 }
531
532 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
533 {
534         struct commit_list *p;
535         int left_count = 0, right_count = 0;
536         int left_first;
537         struct patch_ids ids;
538
539         /* First count the commits on the left and on the right */
540         for (p = list; p; p = p->next) {
541                 struct commit *commit = p->item;
542                 unsigned flags = commit->object.flags;
543                 if (flags & BOUNDARY)
544                         ;
545                 else if (flags & SYMMETRIC_LEFT)
546                         left_count++;
547                 else
548                         right_count++;
549         }
550
551         if (!left_count || !right_count)
552                 return;
553
554         left_first = left_count < right_count;
555         init_patch_ids(&ids);
556         if (revs->diffopt.nr_paths) {
557                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
558                 ids.diffopts.paths = revs->diffopt.paths;
559                 ids.diffopts.pathlens = revs->diffopt.pathlens;
560         }
561
562         /* Compute patch-ids for one side */
563         for (p = list; p; p = p->next) {
564                 struct commit *commit = p->item;
565                 unsigned flags = commit->object.flags;
566
567                 if (flags & BOUNDARY)
568                         continue;
569                 /*
570                  * If we have fewer left, left_first is set and we omit
571                  * commits on the right branch in this loop.  If we have
572                  * fewer right, we skip the left ones.
573                  */
574                 if (left_first != !!(flags & SYMMETRIC_LEFT))
575                         continue;
576                 commit->util = add_commit_patch_id(commit, &ids);
577         }
578
579         /* Check the other side */
580         for (p = list; p; p = p->next) {
581                 struct commit *commit = p->item;
582                 struct patch_id *id;
583                 unsigned flags = commit->object.flags;
584
585                 if (flags & BOUNDARY)
586                         continue;
587                 /*
588                  * If we have fewer left, left_first is set and we omit
589                  * commits on the left branch in this loop.
590                  */
591                 if (left_first == !!(flags & SYMMETRIC_LEFT))
592                         continue;
593
594                 /*
595                  * Have we seen the same patch id?
596                  */
597                 id = has_commit_patch_id(commit, &ids);
598                 if (!id)
599                         continue;
600                 id->seen = 1;
601                 commit->object.flags |= SHOWN;
602         }
603
604         /* Now check the original side for seen ones */
605         for (p = list; p; p = p->next) {
606                 struct commit *commit = p->item;
607                 struct patch_id *ent;
608
609                 ent = commit->util;
610                 if (!ent)
611                         continue;
612                 if (ent->seen)
613                         commit->object.flags |= SHOWN;
614                 commit->util = NULL;
615         }
616
617         free_patch_ids(&ids);
618 }
619
620 /* How many extra uninteresting commits we want to see.. */
621 #define SLOP 5
622
623 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
624 {
625         /*
626          * No source list at all? We're definitely done..
627          */
628         if (!src)
629                 return 0;
630
631         /*
632          * Does the destination list contain entries with a date
633          * before the source list? Definitely _not_ done.
634          */
635         if (date < src->item->date)
636                 return SLOP;
637
638         /*
639          * Does the source list still have interesting commits in
640          * it? Definitely not done..
641          */
642         if (!everybody_uninteresting(src))
643                 return SLOP;
644
645         /* Ok, we're closing in.. */
646         return slop-1;
647 }
648
649 /*
650  * "rev-list --ancestry-path A..B" computes commits that are ancestors
651  * of B but not ancestors of A but further limits the result to those
652  * that are descendants of A.  This takes the list of bottom commits and
653  * the result of "A..B" without --ancestry-path, and limits the latter
654  * further to the ones that can reach one of the commits in "bottom".
655  */
656 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
657 {
658         struct commit_list *p;
659         struct commit_list *rlist = NULL;
660         int made_progress;
661
662         /*
663          * Reverse the list so that it will be likely that we would
664          * process parents before children.
665          */
666         for (p = list; p; p = p->next)
667                 commit_list_insert(p->item, &rlist);
668
669         for (p = bottom; p; p = p->next)
670                 p->item->object.flags |= TMP_MARK;
671
672         /*
673          * Mark the ones that can reach bottom commits in "list",
674          * in a bottom-up fashion.
675          */
676         do {
677                 made_progress = 0;
678                 for (p = rlist; p; p = p->next) {
679                         struct commit *c = p->item;
680                         struct commit_list *parents;
681                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
682                                 continue;
683                         for (parents = c->parents;
684                              parents;
685                              parents = parents->next) {
686                                 if (!(parents->item->object.flags & TMP_MARK))
687                                         continue;
688                                 c->object.flags |= TMP_MARK;
689                                 made_progress = 1;
690                                 break;
691                         }
692                 }
693         } while (made_progress);
694
695         /*
696          * NEEDSWORK: decide if we want to remove parents that are
697          * not marked with TMP_MARK from commit->parents for commits
698          * in the resulting list.  We may not want to do that, though.
699          */
700
701         /*
702          * The ones that are not marked with TMP_MARK are uninteresting
703          */
704         for (p = list; p; p = p->next) {
705                 struct commit *c = p->item;
706                 if (c->object.flags & TMP_MARK)
707                         continue;
708                 c->object.flags |= UNINTERESTING;
709         }
710
711         /* We are done with the TMP_MARK */
712         for (p = list; p; p = p->next)
713                 p->item->object.flags &= ~TMP_MARK;
714         for (p = bottom; p; p = p->next)
715                 p->item->object.flags &= ~TMP_MARK;
716         free_commit_list(rlist);
717 }
718
719 /*
720  * Before walking the history, keep the set of "negative" refs the
721  * caller has asked to exclude.
722  *
723  * This is used to compute "rev-list --ancestry-path A..B", as we need
724  * to filter the result of "A..B" further to the ones that can actually
725  * reach A.
726  */
727 static struct commit_list *collect_bottom_commits(struct commit_list *list)
728 {
729         struct commit_list *elem, *bottom = NULL;
730         for (elem = list; elem; elem = elem->next)
731                 if (elem->item->object.flags & UNINTERESTING)
732                         commit_list_insert(elem->item, &bottom);
733         return bottom;
734 }
735
736 /* Assumes either left_only or right_only is set */
737 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
738 {
739         struct commit_list *p;
740
741         for (p = list; p; p = p->next) {
742                 struct commit *commit = p->item;
743
744                 if (revs->right_only) {
745                         if (commit->object.flags & SYMMETRIC_LEFT)
746                                 commit->object.flags |= SHOWN;
747                 } else  /* revs->left_only is set */
748                         if (!(commit->object.flags & SYMMETRIC_LEFT))
749                                 commit->object.flags |= SHOWN;
750         }
751 }
752
753 static int limit_list(struct rev_info *revs)
754 {
755         int slop = SLOP;
756         unsigned long date = ~0ul;
757         struct commit_list *list = revs->commits;
758         struct commit_list *newlist = NULL;
759         struct commit_list **p = &newlist;
760         struct commit_list *bottom = NULL;
761
762         if (revs->ancestry_path) {
763                 bottom = collect_bottom_commits(list);
764                 if (!bottom)
765                         die("--ancestry-path given but there are no bottom commits");
766         }
767
768         while (list) {
769                 struct commit_list *entry = list;
770                 struct commit *commit = list->item;
771                 struct object *obj = &commit->object;
772                 show_early_output_fn_t show;
773
774                 list = list->next;
775                 free(entry);
776
777                 if (revs->max_age != -1 && (commit->date < revs->max_age))
778                         obj->flags |= UNINTERESTING;
779                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
780                         return -1;
781                 if (obj->flags & UNINTERESTING) {
782                         mark_parents_uninteresting(commit);
783                         if (revs->show_all)
784                                 p = &commit_list_insert(commit, p)->next;
785                         slop = still_interesting(list, date, slop);
786                         if (slop)
787                                 continue;
788                         /* If showing all, add the whole pending list to the end */
789                         if (revs->show_all)
790                                 *p = list;
791                         break;
792                 }
793                 if (revs->min_age != -1 && (commit->date > revs->min_age))
794                         continue;
795                 date = commit->date;
796                 p = &commit_list_insert(commit, p)->next;
797
798                 show = show_early_output;
799                 if (!show)
800                         continue;
801
802                 show(revs, newlist);
803                 show_early_output = NULL;
804         }
805         if (revs->cherry_pick)
806                 cherry_pick_list(newlist, revs);
807
808         if (revs->left_only || revs->right_only)
809                 limit_left_right(newlist, revs);
810
811         if (bottom) {
812                 limit_to_ancestry(bottom, newlist);
813                 free_commit_list(bottom);
814         }
815
816         revs->commits = newlist;
817         return 0;
818 }
819
820 struct all_refs_cb {
821         int all_flags;
822         int warned_bad_reflog;
823         struct rev_info *all_revs;
824         const char *name_for_errormsg;
825 };
826
827 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
828 {
829         struct all_refs_cb *cb = cb_data;
830         struct object *object = get_reference(cb->all_revs, path, sha1,
831                                               cb->all_flags);
832         add_pending_object(cb->all_revs, object, path);
833         return 0;
834 }
835
836 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
837         unsigned flags)
838 {
839         cb->all_revs = revs;
840         cb->all_flags = flags;
841 }
842
843 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
844                 int (*for_each)(const char *, each_ref_fn, void *))
845 {
846         struct all_refs_cb cb;
847         init_all_refs_cb(&cb, revs, flags);
848         for_each(submodule, handle_one_ref, &cb);
849 }
850
851 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
852 {
853         struct all_refs_cb *cb = cb_data;
854         if (!is_null_sha1(sha1)) {
855                 struct object *o = parse_object(sha1);
856                 if (o) {
857                         o->flags |= cb->all_flags;
858                         add_pending_object(cb->all_revs, o, "");
859                 }
860                 else if (!cb->warned_bad_reflog) {
861                         warning("reflog of '%s' references pruned commits",
862                                 cb->name_for_errormsg);
863                         cb->warned_bad_reflog = 1;
864                 }
865         }
866 }
867
868 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
869                 const char *email, unsigned long timestamp, int tz,
870                 const char *message, void *cb_data)
871 {
872         handle_one_reflog_commit(osha1, cb_data);
873         handle_one_reflog_commit(nsha1, cb_data);
874         return 0;
875 }
876
877 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
878 {
879         struct all_refs_cb *cb = cb_data;
880         cb->warned_bad_reflog = 0;
881         cb->name_for_errormsg = path;
882         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
883         return 0;
884 }
885
886 static void handle_reflog(struct rev_info *revs, unsigned flags)
887 {
888         struct all_refs_cb cb;
889         cb.all_revs = revs;
890         cb.all_flags = flags;
891         for_each_reflog(handle_one_reflog, &cb);
892 }
893
894 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
895 {
896         unsigned char sha1[20];
897         struct object *it;
898         struct commit *commit;
899         struct commit_list *parents;
900
901         if (*arg == '^') {
902                 flags ^= UNINTERESTING;
903                 arg++;
904         }
905         if (get_sha1(arg, sha1))
906                 return 0;
907         while (1) {
908                 it = get_reference(revs, arg, sha1, 0);
909                 if (it->type != OBJ_TAG)
910                         break;
911                 if (!((struct tag*)it)->tagged)
912                         return 0;
913                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
914         }
915         if (it->type != OBJ_COMMIT)
916                 return 0;
917         commit = (struct commit *)it;
918         for (parents = commit->parents; parents; parents = parents->next) {
919                 it = &parents->item->object;
920                 it->flags |= flags;
921                 add_pending_object(revs, it, arg);
922         }
923         return 1;
924 }
925
926 void init_revisions(struct rev_info *revs, const char *prefix)
927 {
928         memset(revs, 0, sizeof(*revs));
929
930         revs->abbrev = DEFAULT_ABBREV;
931         revs->ignore_merges = 1;
932         revs->simplify_history = 1;
933         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
934         DIFF_OPT_SET(&revs->pruning, QUICK);
935         revs->pruning.add_remove = file_add_remove;
936         revs->pruning.change = file_change;
937         revs->lifo = 1;
938         revs->dense = 1;
939         revs->prefix = prefix;
940         revs->max_age = -1;
941         revs->min_age = -1;
942         revs->skip_count = -1;
943         revs->max_count = -1;
944
945         revs->commit_format = CMIT_FMT_DEFAULT;
946
947         revs->grep_filter.status_only = 1;
948         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
949         revs->grep_filter.header_tail = &(revs->grep_filter.header_list);
950         revs->grep_filter.regflags = REG_NEWLINE;
951
952         diff_setup(&revs->diffopt);
953         if (prefix && !revs->diffopt.prefix) {
954                 revs->diffopt.prefix = prefix;
955                 revs->diffopt.prefix_length = strlen(prefix);
956         }
957 }
958
959 static void add_pending_commit_list(struct rev_info *revs,
960                                     struct commit_list *commit_list,
961                                     unsigned int flags)
962 {
963         while (commit_list) {
964                 struct object *object = &commit_list->item->object;
965                 object->flags |= flags;
966                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
967                 commit_list = commit_list->next;
968         }
969 }
970
971 static void prepare_show_merge(struct rev_info *revs)
972 {
973         struct commit_list *bases;
974         struct commit *head, *other;
975         unsigned char sha1[20];
976         const char **prune = NULL;
977         int i, prune_num = 1; /* counting terminating NULL */
978
979         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
980                 die("--merge without HEAD?");
981         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
982                 die("--merge without MERGE_HEAD?");
983         add_pending_object(revs, &head->object, "HEAD");
984         add_pending_object(revs, &other->object, "MERGE_HEAD");
985         bases = get_merge_bases(head, other, 1);
986         add_pending_commit_list(revs, bases, UNINTERESTING);
987         free_commit_list(bases);
988         head->object.flags |= SYMMETRIC_LEFT;
989
990         if (!active_nr)
991                 read_cache();
992         for (i = 0; i < active_nr; i++) {
993                 struct cache_entry *ce = active_cache[i];
994                 if (!ce_stage(ce))
995                         continue;
996                 if (ce_path_match(ce, revs->prune_data)) {
997                         prune_num++;
998                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
999                         prune[prune_num-2] = ce->name;
1000                         prune[prune_num-1] = NULL;
1001                 }
1002                 while ((i+1 < active_nr) &&
1003                        ce_same_name(ce, active_cache[i+1]))
1004                         i++;
1005         }
1006         revs->prune_data = prune;
1007         revs->limited = 1;
1008 }
1009
1010 int handle_revision_arg(const char *arg, struct rev_info *revs,
1011                         int flags,
1012                         int cant_be_filename)
1013 {
1014         unsigned mode;
1015         char *dotdot;
1016         struct object *object;
1017         unsigned char sha1[20];
1018         int local_flags;
1019
1020         dotdot = strstr(arg, "..");
1021         if (dotdot) {
1022                 unsigned char from_sha1[20];
1023                 const char *next = dotdot + 2;
1024                 const char *this = arg;
1025                 int symmetric = *next == '.';
1026                 unsigned int flags_exclude = flags ^ UNINTERESTING;
1027
1028                 *dotdot = 0;
1029                 next += symmetric;
1030
1031                 if (!*next)
1032                         next = "HEAD";
1033                 if (dotdot == arg)
1034                         this = "HEAD";
1035                 if (!get_sha1(this, from_sha1) &&
1036                     !get_sha1(next, sha1)) {
1037                         struct commit *a, *b;
1038                         struct commit_list *exclude;
1039
1040                         a = lookup_commit_reference(from_sha1);
1041                         b = lookup_commit_reference(sha1);
1042                         if (!a || !b) {
1043                                 die(symmetric ?
1044                                     "Invalid symmetric difference expression %s...%s" :
1045                                     "Invalid revision range %s..%s",
1046                                     arg, next);
1047                         }
1048
1049                         if (!cant_be_filename) {
1050                                 *dotdot = '.';
1051                                 verify_non_filename(revs->prefix, arg);
1052                         }
1053
1054                         if (symmetric) {
1055                                 exclude = get_merge_bases(a, b, 1);
1056                                 add_pending_commit_list(revs, exclude,
1057                                                         flags_exclude);
1058                                 free_commit_list(exclude);
1059                                 a->object.flags |= flags | SYMMETRIC_LEFT;
1060                         } else
1061                                 a->object.flags |= flags_exclude;
1062                         b->object.flags |= flags;
1063                         add_pending_object(revs, &a->object, this);
1064                         add_pending_object(revs, &b->object, next);
1065                         return 0;
1066                 }
1067                 *dotdot = '.';
1068         }
1069         dotdot = strstr(arg, "^@");
1070         if (dotdot && !dotdot[2]) {
1071                 *dotdot = 0;
1072                 if (add_parents_only(revs, arg, flags))
1073                         return 0;
1074                 *dotdot = '^';
1075         }
1076         dotdot = strstr(arg, "^!");
1077         if (dotdot && !dotdot[2]) {
1078                 *dotdot = 0;
1079                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
1080                         *dotdot = '^';
1081         }
1082
1083         local_flags = 0;
1084         if (*arg == '^') {
1085                 local_flags = UNINTERESTING;
1086                 arg++;
1087         }
1088         if (get_sha1_with_mode(arg, sha1, &mode))
1089                 return -1;
1090         if (!cant_be_filename)
1091                 verify_non_filename(revs->prefix, arg);
1092         object = get_reference(revs, arg, sha1, flags ^ local_flags);
1093         add_pending_object_with_mode(revs, object, arg, mode);
1094         return 0;
1095 }
1096
1097 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb, const char ***prune_data)
1098 {
1099         const char **prune = *prune_data;
1100         int prune_nr;
1101         int prune_alloc;
1102
1103         /* count existing ones */
1104         if (!prune)
1105                 prune_nr = 0;
1106         else
1107                 for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1108                         ;
1109         prune_alloc = prune_nr; /* not really, but we do not know */
1110
1111         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
1112                 int len = sb->len;
1113                 if (len && sb->buf[len - 1] == '\n')
1114                         sb->buf[--len] = '\0';
1115                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1116                 prune[prune_nr++] = xstrdup(sb->buf);
1117         }
1118         if (prune) {
1119                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1120                 prune[prune_nr] = NULL;
1121         }
1122         *prune_data = prune;
1123 }
1124
1125 static void read_revisions_from_stdin(struct rev_info *revs, const char ***prune)
1126 {
1127         struct strbuf sb;
1128         int seen_dashdash = 0;
1129
1130         strbuf_init(&sb, 1000);
1131         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1132                 int len = sb.len;
1133                 if (len && sb.buf[len - 1] == '\n')
1134                         sb.buf[--len] = '\0';
1135                 if (!len)
1136                         break;
1137                 if (sb.buf[0] == '-') {
1138                         if (len == 2 && sb.buf[1] == '-') {
1139                                 seen_dashdash = 1;
1140                                 break;
1141                         }
1142                         die("options not supported in --stdin mode");
1143                 }
1144                 if (handle_revision_arg(sb.buf, revs, 0, 1))
1145                         die("bad revision '%s'", sb.buf);
1146         }
1147         if (seen_dashdash)
1148                 read_pathspec_from_stdin(revs, &sb, prune);
1149         strbuf_release(&sb);
1150 }
1151
1152 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1153 {
1154         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1155 }
1156
1157 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1158 {
1159         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1160 }
1161
1162 static void add_message_grep(struct rev_info *revs, const char *pattern)
1163 {
1164         add_grep(revs, pattern, GREP_PATTERN_BODY);
1165 }
1166
1167 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1168                                int *unkc, const char **unkv)
1169 {
1170         const char *arg = argv[0];
1171         const char *optarg;
1172         int argcount;
1173
1174         /* pseudo revision arguments */
1175         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1176             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1177             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1178             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1179             !strcmp(arg, "--bisect"))
1180         {
1181                 unkv[(*unkc)++] = arg;
1182                 return 1;
1183         }
1184
1185         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1186                 revs->max_count = atoi(optarg);
1187                 revs->no_walk = 0;
1188                 return argcount;
1189         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1190                 revs->skip_count = atoi(optarg);
1191                 return argcount;
1192         } else if ((*arg == '-') && isdigit(arg[1])) {
1193         /* accept -<digit>, like traditional "head" */
1194                 revs->max_count = atoi(arg + 1);
1195                 revs->no_walk = 0;
1196         } else if (!strcmp(arg, "-n")) {
1197                 if (argc <= 1)
1198                         return error("-n requires an argument");
1199                 revs->max_count = atoi(argv[1]);
1200                 revs->no_walk = 0;
1201                 return 2;
1202         } else if (!prefixcmp(arg, "-n")) {
1203                 revs->max_count = atoi(arg + 2);
1204                 revs->no_walk = 0;
1205         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1206                 revs->max_age = atoi(optarg);
1207                 return argcount;
1208         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1209                 revs->max_age = approxidate(optarg);
1210                 return argcount;
1211         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1212                 revs->max_age = approxidate(optarg);
1213                 return argcount;
1214         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1215                 revs->min_age = atoi(optarg);
1216                 return argcount;
1217         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1218                 revs->min_age = approxidate(optarg);
1219                 return argcount;
1220         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1221                 revs->min_age = approxidate(optarg);
1222                 return argcount;
1223         } else if (!strcmp(arg, "--first-parent")) {
1224                 revs->first_parent_only = 1;
1225         } else if (!strcmp(arg, "--ancestry-path")) {
1226                 revs->ancestry_path = 1;
1227                 revs->simplify_history = 0;
1228                 revs->limited = 1;
1229         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1230                 init_reflog_walk(&revs->reflog_info);
1231         } else if (!strcmp(arg, "--default")) {
1232                 if (argc <= 1)
1233                         return error("bad --default argument");
1234                 revs->def = argv[1];
1235                 return 2;
1236         } else if (!strcmp(arg, "--merge")) {
1237                 revs->show_merge = 1;
1238         } else if (!strcmp(arg, "--topo-order")) {
1239                 revs->lifo = 1;
1240                 revs->topo_order = 1;
1241         } else if (!strcmp(arg, "--simplify-merges")) {
1242                 revs->simplify_merges = 1;
1243                 revs->rewrite_parents = 1;
1244                 revs->simplify_history = 0;
1245                 revs->limited = 1;
1246         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1247                 revs->simplify_merges = 1;
1248                 revs->rewrite_parents = 1;
1249                 revs->simplify_history = 0;
1250                 revs->simplify_by_decoration = 1;
1251                 revs->limited = 1;
1252                 revs->prune = 1;
1253                 load_ref_decorations(DECORATE_SHORT_REFS);
1254         } else if (!strcmp(arg, "--date-order")) {
1255                 revs->lifo = 0;
1256                 revs->topo_order = 1;
1257         } else if (!prefixcmp(arg, "--early-output")) {
1258                 int count = 100;
1259                 switch (arg[14]) {
1260                 case '=':
1261                         count = atoi(arg+15);
1262                         /* Fallthrough */
1263                 case 0:
1264                         revs->topo_order = 1;
1265                        revs->early_output = count;
1266                 }
1267         } else if (!strcmp(arg, "--parents")) {
1268                 revs->rewrite_parents = 1;
1269                 revs->print_parents = 1;
1270         } else if (!strcmp(arg, "--dense")) {
1271                 revs->dense = 1;
1272         } else if (!strcmp(arg, "--sparse")) {
1273                 revs->dense = 0;
1274         } else if (!strcmp(arg, "--show-all")) {
1275                 revs->show_all = 1;
1276         } else if (!strcmp(arg, "--remove-empty")) {
1277                 revs->remove_empty_trees = 1;
1278         } else if (!strcmp(arg, "--merges")) {
1279                 revs->merges_only = 1;
1280         } else if (!strcmp(arg, "--no-merges")) {
1281                 revs->no_merges = 1;
1282         } else if (!strcmp(arg, "--boundary")) {
1283                 revs->boundary = 1;
1284         } else if (!strcmp(arg, "--left-right")) {
1285                 revs->left_right = 1;
1286         } else if (!strcmp(arg, "--left-only")) {
1287                 if (revs->right_only)
1288                         die("--left-only is incompatible with --right-only");
1289                 revs->left_only = 1;
1290         } else if (!strcmp(arg, "--right-only")) {
1291                 if (revs->left_only)
1292                         die("--right-only is incompatible with --left-only");
1293                 revs->right_only = 1;
1294         } else if (!strcmp(arg, "--count")) {
1295                 revs->count = 1;
1296         } else if (!strcmp(arg, "--cherry-pick")) {
1297                 revs->cherry_pick = 1;
1298                 revs->limited = 1;
1299         } else if (!strcmp(arg, "--objects")) {
1300                 revs->tag_objects = 1;
1301                 revs->tree_objects = 1;
1302                 revs->blob_objects = 1;
1303         } else if (!strcmp(arg, "--objects-edge")) {
1304                 revs->tag_objects = 1;
1305                 revs->tree_objects = 1;
1306                 revs->blob_objects = 1;
1307                 revs->edge_hint = 1;
1308         } else if (!strcmp(arg, "--unpacked")) {
1309                 revs->unpacked = 1;
1310         } else if (!prefixcmp(arg, "--unpacked=")) {
1311                 die("--unpacked=<packfile> no longer supported.");
1312         } else if (!strcmp(arg, "-r")) {
1313                 revs->diff = 1;
1314                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1315         } else if (!strcmp(arg, "-t")) {
1316                 revs->diff = 1;
1317                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1318                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1319         } else if (!strcmp(arg, "-m")) {
1320                 revs->ignore_merges = 0;
1321         } else if (!strcmp(arg, "-c")) {
1322                 revs->diff = 1;
1323                 revs->dense_combined_merges = 0;
1324                 revs->combine_merges = 1;
1325         } else if (!strcmp(arg, "--cc")) {
1326                 revs->diff = 1;
1327                 revs->dense_combined_merges = 1;
1328                 revs->combine_merges = 1;
1329         } else if (!strcmp(arg, "-v")) {
1330                 revs->verbose_header = 1;
1331         } else if (!strcmp(arg, "--pretty")) {
1332                 revs->verbose_header = 1;
1333                 revs->pretty_given = 1;
1334                 get_commit_format(arg+8, revs);
1335         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1336                 /*
1337                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1338                  * not allowed, since the argument is optional.
1339                  */
1340                 revs->verbose_header = 1;
1341                 revs->pretty_given = 1;
1342                 get_commit_format(arg+9, revs);
1343         } else if (!strcmp(arg, "--show-notes")) {
1344                 revs->show_notes = 1;
1345                 revs->show_notes_given = 1;
1346         } else if (!prefixcmp(arg, "--show-notes=")) {
1347                 struct strbuf buf = STRBUF_INIT;
1348                 revs->show_notes = 1;
1349                 revs->show_notes_given = 1;
1350                 if (!revs->notes_opt.extra_notes_refs)
1351                         revs->notes_opt.extra_notes_refs = xcalloc(1, sizeof(struct string_list));
1352                 if (!prefixcmp(arg+13, "refs/"))
1353                         /* happy */;
1354                 else if (!prefixcmp(arg+13, "notes/"))
1355                         strbuf_addstr(&buf, "refs/");
1356                 else
1357                         strbuf_addstr(&buf, "refs/notes/");
1358                 strbuf_addstr(&buf, arg+13);
1359                 string_list_append(revs->notes_opt.extra_notes_refs,
1360                                    strbuf_detach(&buf, NULL));
1361         } else if (!strcmp(arg, "--no-notes")) {
1362                 revs->show_notes = 0;
1363                 revs->show_notes_given = 1;
1364         } else if (!strcmp(arg, "--standard-notes")) {
1365                 revs->show_notes_given = 1;
1366                 revs->notes_opt.suppress_default_notes = 0;
1367         } else if (!strcmp(arg, "--no-standard-notes")) {
1368                 revs->notes_opt.suppress_default_notes = 1;
1369         } else if (!strcmp(arg, "--oneline")) {
1370                 revs->verbose_header = 1;
1371                 get_commit_format("oneline", revs);
1372                 revs->pretty_given = 1;
1373                 revs->abbrev_commit = 1;
1374         } else if (!strcmp(arg, "--graph")) {
1375                 revs->topo_order = 1;
1376                 revs->rewrite_parents = 1;
1377                 revs->graph = graph_init(revs);
1378         } else if (!strcmp(arg, "--root")) {
1379                 revs->show_root_diff = 1;
1380         } else if (!strcmp(arg, "--no-commit-id")) {
1381                 revs->no_commit_id = 1;
1382         } else if (!strcmp(arg, "--always")) {
1383                 revs->always_show_header = 1;
1384         } else if (!strcmp(arg, "--no-abbrev")) {
1385                 revs->abbrev = 0;
1386         } else if (!strcmp(arg, "--abbrev")) {
1387                 revs->abbrev = DEFAULT_ABBREV;
1388         } else if (!prefixcmp(arg, "--abbrev=")) {
1389                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1390                 if (revs->abbrev < MINIMUM_ABBREV)
1391                         revs->abbrev = MINIMUM_ABBREV;
1392                 else if (revs->abbrev > 40)
1393                         revs->abbrev = 40;
1394         } else if (!strcmp(arg, "--abbrev-commit")) {
1395                 revs->abbrev_commit = 1;
1396         } else if (!strcmp(arg, "--full-diff")) {
1397                 revs->diff = 1;
1398                 revs->full_diff = 1;
1399         } else if (!strcmp(arg, "--full-history")) {
1400                 revs->simplify_history = 0;
1401         } else if (!strcmp(arg, "--relative-date")) {
1402                 revs->date_mode = DATE_RELATIVE;
1403                 revs->date_mode_explicit = 1;
1404         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
1405                 revs->date_mode = parse_date_format(optarg);
1406                 revs->date_mode_explicit = 1;
1407                 return argcount;
1408         } else if (!strcmp(arg, "--log-size")) {
1409                 revs->show_log_size = 1;
1410         }
1411         /*
1412          * Grepping the commit log
1413          */
1414         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
1415                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
1416                 return argcount;
1417         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
1418                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
1419                 return argcount;
1420         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
1421                 add_message_grep(revs, optarg);
1422                 return argcount;
1423         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1424                 revs->grep_filter.regflags |= REG_EXTENDED;
1425         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1426                 revs->grep_filter.regflags |= REG_ICASE;
1427         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1428                 revs->grep_filter.fixed = 1;
1429         } else if (!strcmp(arg, "--all-match")) {
1430                 revs->grep_filter.all_match = 1;
1431         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
1432                 if (strcmp(optarg, "none"))
1433                         git_log_output_encoding = xstrdup(optarg);
1434                 else
1435                         git_log_output_encoding = "";
1436                 return argcount;
1437         } else if (!strcmp(arg, "--reverse")) {
1438                 revs->reverse ^= 1;
1439         } else if (!strcmp(arg, "--children")) {
1440                 revs->children.name = "children";
1441                 revs->limited = 1;
1442         } else {
1443                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1444                 if (!opts)
1445                         unkv[(*unkc)++] = arg;
1446                 return opts;
1447         }
1448
1449         return 1;
1450 }
1451
1452 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1453                         const struct option *options,
1454                         const char * const usagestr[])
1455 {
1456         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1457                                     &ctx->cpidx, ctx->out);
1458         if (n <= 0) {
1459                 error("unknown option `%s'", ctx->argv[0]);
1460                 usage_with_options(usagestr, options);
1461         }
1462         ctx->argv += n;
1463         ctx->argc -= n;
1464 }
1465
1466 static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1467 {
1468         return for_each_ref_in_submodule(submodule, "refs/bisect/bad", fn, cb_data);
1469 }
1470
1471 static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1472 {
1473         return for_each_ref_in_submodule(submodule, "refs/bisect/good", fn, cb_data);
1474 }
1475
1476 static void append_prune_data(const char ***prune_data, const char **av)
1477 {
1478         const char **prune = *prune_data;
1479         int prune_nr;
1480         int prune_alloc;
1481
1482         if (!prune) {
1483                 *prune_data = av;
1484                 return;
1485         }
1486
1487         /* count existing ones */
1488         for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1489                 ;
1490         prune_alloc = prune_nr; /* not really, but we do not know */
1491
1492         while (*av) {
1493                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1494                 prune[prune_nr++] = *av;
1495                 av++;
1496         }
1497         if (prune) {
1498                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1499                 prune[prune_nr] = NULL;
1500         }
1501         *prune_data = prune;
1502 }
1503
1504 /*
1505  * Parse revision information, filling in the "rev_info" structure,
1506  * and removing the used arguments from the argument list.
1507  *
1508  * Returns the number of arguments left that weren't recognized
1509  * (which are also moved to the head of the argument list)
1510  */
1511 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
1512 {
1513         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0;
1514         const char **prune_data = NULL;
1515         const char *submodule = NULL;
1516         const char *optarg;
1517         int argcount;
1518
1519         if (opt)
1520                 submodule = opt->submodule;
1521
1522         /* First, search for "--" */
1523         seen_dashdash = 0;
1524         for (i = 1; i < argc; i++) {
1525                 const char *arg = argv[i];
1526                 if (strcmp(arg, "--"))
1527                         continue;
1528                 argv[i] = NULL;
1529                 argc = i;
1530                 if (argv[i + 1])
1531                         prune_data = argv + i + 1;
1532                 seen_dashdash = 1;
1533                 break;
1534         }
1535
1536         /* Second, deal with arguments and options */
1537         flags = 0;
1538         read_from_stdin = 0;
1539         for (left = i = 1; i < argc; i++) {
1540                 const char *arg = argv[i];
1541                 if (*arg == '-') {
1542                         int opts;
1543
1544                         if (!strcmp(arg, "--all")) {
1545                                 handle_refs(submodule, revs, flags, for_each_ref_submodule);
1546                                 handle_refs(submodule, revs, flags, head_ref_submodule);
1547                                 continue;
1548                         }
1549                         if (!strcmp(arg, "--branches")) {
1550                                 handle_refs(submodule, revs, flags, for_each_branch_ref_submodule);
1551                                 continue;
1552                         }
1553                         if (!strcmp(arg, "--bisect")) {
1554                                 handle_refs(submodule, revs, flags, for_each_bad_bisect_ref);
1555                                 handle_refs(submodule, revs, flags ^ UNINTERESTING, for_each_good_bisect_ref);
1556                                 revs->bisect = 1;
1557                                 continue;
1558                         }
1559                         if (!strcmp(arg, "--tags")) {
1560                                 handle_refs(submodule, revs, flags, for_each_tag_ref_submodule);
1561                                 continue;
1562                         }
1563                         if (!strcmp(arg, "--remotes")) {
1564                                 handle_refs(submodule, revs, flags, for_each_remote_ref_submodule);
1565                                 continue;
1566                         }
1567                         if ((argcount = parse_long_opt("glob", argv + i, &optarg))) {
1568                                 struct all_refs_cb cb;
1569                                 i += argcount - 1;
1570                                 init_all_refs_cb(&cb, revs, flags);
1571                                 for_each_glob_ref(handle_one_ref, optarg, &cb);
1572                                 continue;
1573                         }
1574                         if (!prefixcmp(arg, "--branches=")) {
1575                                 struct all_refs_cb cb;
1576                                 init_all_refs_cb(&cb, revs, flags);
1577                                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
1578                                 continue;
1579                         }
1580                         if (!prefixcmp(arg, "--tags=")) {
1581                                 struct all_refs_cb cb;
1582                                 init_all_refs_cb(&cb, revs, flags);
1583                                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
1584                                 continue;
1585                         }
1586                         if (!prefixcmp(arg, "--remotes=")) {
1587                                 struct all_refs_cb cb;
1588                                 init_all_refs_cb(&cb, revs, flags);
1589                                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
1590                                 continue;
1591                         }
1592                         if (!strcmp(arg, "--reflog")) {
1593                                 handle_reflog(revs, flags);
1594                                 continue;
1595                         }
1596                         if (!strcmp(arg, "--not")) {
1597                                 flags ^= UNINTERESTING;
1598                                 continue;
1599                         }
1600                         if (!strcmp(arg, "--no-walk")) {
1601                                 revs->no_walk = 1;
1602                                 continue;
1603                         }
1604                         if (!strcmp(arg, "--do-walk")) {
1605                                 revs->no_walk = 0;
1606                                 continue;
1607                         }
1608                         if (!strcmp(arg, "--stdin")) {
1609                                 if (revs->disable_stdin) {
1610                                         argv[left++] = arg;
1611                                         continue;
1612                                 }
1613                                 if (read_from_stdin++)
1614                                         die("--stdin given twice?");
1615                                 read_revisions_from_stdin(revs, &prune_data);
1616                                 continue;
1617                         }
1618
1619                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1620                         if (opts > 0) {
1621                                 i += opts - 1;
1622                                 continue;
1623                         }
1624                         if (opts < 0)
1625                                 exit(128);
1626                         continue;
1627                 }
1628
1629                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1630                         int j;
1631                         if (seen_dashdash || *arg == '^')
1632                                 die("bad revision '%s'", arg);
1633
1634                         /* If we didn't have a "--":
1635                          * (1) all filenames must exist;
1636                          * (2) all rev-args must not be interpretable
1637                          *     as a valid filename.
1638                          * but the latter we have checked in the main loop.
1639                          */
1640                         for (j = i; j < argc; j++)
1641                                 verify_filename(revs->prefix, argv[j]);
1642
1643                         append_prune_data(&prune_data, argv + i);
1644                         break;
1645                 }
1646                 else
1647                         got_rev_arg = 1;
1648         }
1649
1650         if (prune_data)
1651                 revs->prune_data = get_pathspec(revs->prefix, prune_data);
1652
1653         if (revs->def == NULL)
1654                 revs->def = opt ? opt->def : NULL;
1655         if (opt && opt->tweak)
1656                 opt->tweak(revs, opt);
1657         if (revs->show_merge)
1658                 prepare_show_merge(revs);
1659         if (revs->def && !revs->pending.nr && !got_rev_arg) {
1660                 unsigned char sha1[20];
1661                 struct object *object;
1662                 unsigned mode;
1663                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1664                         die("bad default revision '%s'", revs->def);
1665                 object = get_reference(revs, revs->def, sha1, 0);
1666                 add_pending_object_with_mode(revs, object, revs->def, mode);
1667         }
1668
1669         /* Did the user ask for any diff output? Run the diff! */
1670         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1671                 revs->diff = 1;
1672
1673         /* Pickaxe, diff-filter and rename following need diffs */
1674         if (revs->diffopt.pickaxe ||
1675             revs->diffopt.filter ||
1676             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1677                 revs->diff = 1;
1678
1679         if (revs->topo_order)
1680                 revs->limited = 1;
1681
1682         if (revs->prune_data) {
1683                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1684                 /* Can't prune commits with rename following: the paths change.. */
1685                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1686                         revs->prune = 1;
1687                 if (!revs->full_diff)
1688                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1689         }
1690         if (revs->combine_merges)
1691                 revs->ignore_merges = 0;
1692         revs->diffopt.abbrev = revs->abbrev;
1693         if (diff_setup_done(&revs->diffopt) < 0)
1694                 die("diff_setup_done failed");
1695
1696         compile_grep_patterns(&revs->grep_filter);
1697
1698         if (revs->reverse && revs->reflog_info)
1699                 die("cannot combine --reverse with --walk-reflogs");
1700         if (revs->rewrite_parents && revs->children.name)
1701                 die("cannot combine --parents and --children");
1702
1703         /*
1704          * Limitations on the graph functionality
1705          */
1706         if (revs->reverse && revs->graph)
1707                 die("cannot combine --reverse with --graph");
1708
1709         if (revs->reflog_info && revs->graph)
1710                 die("cannot combine --walk-reflogs with --graph");
1711
1712         return left;
1713 }
1714
1715 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1716 {
1717         struct commit_list *l = xcalloc(1, sizeof(*l));
1718
1719         l->item = child;
1720         l->next = add_decoration(&revs->children, &parent->object, l);
1721 }
1722
1723 static int remove_duplicate_parents(struct commit *commit)
1724 {
1725         struct commit_list **pp, *p;
1726         int surviving_parents;
1727
1728         /* Examine existing parents while marking ones we have seen... */
1729         pp = &commit->parents;
1730         while ((p = *pp) != NULL) {
1731                 struct commit *parent = p->item;
1732                 if (parent->object.flags & TMP_MARK) {
1733                         *pp = p->next;
1734                         continue;
1735                 }
1736                 parent->object.flags |= TMP_MARK;
1737                 pp = &p->next;
1738         }
1739         /* count them while clearing the temporary mark */
1740         surviving_parents = 0;
1741         for (p = commit->parents; p; p = p->next) {
1742                 p->item->object.flags &= ~TMP_MARK;
1743                 surviving_parents++;
1744         }
1745         return surviving_parents;
1746 }
1747
1748 struct merge_simplify_state {
1749         struct commit *simplified;
1750 };
1751
1752 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1753 {
1754         struct merge_simplify_state *st;
1755
1756         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1757         if (!st) {
1758                 st = xcalloc(1, sizeof(*st));
1759                 add_decoration(&revs->merge_simplification, &commit->object, st);
1760         }
1761         return st;
1762 }
1763
1764 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1765 {
1766         struct commit_list *p;
1767         struct merge_simplify_state *st, *pst;
1768         int cnt;
1769
1770         st = locate_simplify_state(revs, commit);
1771
1772         /*
1773          * Have we handled this one?
1774          */
1775         if (st->simplified)
1776                 return tail;
1777
1778         /*
1779          * An UNINTERESTING commit simplifies to itself, so does a
1780          * root commit.  We do not rewrite parents of such commit
1781          * anyway.
1782          */
1783         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1784                 st->simplified = commit;
1785                 return tail;
1786         }
1787
1788         /*
1789          * Do we know what commit all of our parents should be rewritten to?
1790          * Otherwise we are not ready to rewrite this one yet.
1791          */
1792         for (cnt = 0, p = commit->parents; p; p = p->next) {
1793                 pst = locate_simplify_state(revs, p->item);
1794                 if (!pst->simplified) {
1795                         tail = &commit_list_insert(p->item, tail)->next;
1796                         cnt++;
1797                 }
1798         }
1799         if (cnt) {
1800                 tail = &commit_list_insert(commit, tail)->next;
1801                 return tail;
1802         }
1803
1804         /*
1805          * Rewrite our list of parents.
1806          */
1807         for (p = commit->parents; p; p = p->next) {
1808                 pst = locate_simplify_state(revs, p->item);
1809                 p->item = pst->simplified;
1810         }
1811         cnt = remove_duplicate_parents(commit);
1812
1813         /*
1814          * It is possible that we are a merge and one side branch
1815          * does not have any commit that touches the given paths;
1816          * in such a case, the immediate parents will be rewritten
1817          * to different commits.
1818          *
1819          *      o----X          X: the commit we are looking at;
1820          *     /    /           o: a commit that touches the paths;
1821          * ---o----'
1822          *
1823          * Further reduce the parents by removing redundant parents.
1824          */
1825         if (1 < cnt) {
1826                 struct commit_list *h = reduce_heads(commit->parents);
1827                 cnt = commit_list_count(h);
1828                 free_commit_list(commit->parents);
1829                 commit->parents = h;
1830         }
1831
1832         /*
1833          * A commit simplifies to itself if it is a root, if it is
1834          * UNINTERESTING, if it touches the given paths, or if it is a
1835          * merge and its parents simplifies to more than one commits
1836          * (the first two cases are already handled at the beginning of
1837          * this function).
1838          *
1839          * Otherwise, it simplifies to what its sole parent simplifies to.
1840          */
1841         if (!cnt ||
1842             (commit->object.flags & UNINTERESTING) ||
1843             !(commit->object.flags & TREESAME) ||
1844             (1 < cnt))
1845                 st->simplified = commit;
1846         else {
1847                 pst = locate_simplify_state(revs, commit->parents->item);
1848                 st->simplified = pst->simplified;
1849         }
1850         return tail;
1851 }
1852
1853 static void simplify_merges(struct rev_info *revs)
1854 {
1855         struct commit_list *list;
1856         struct commit_list *yet_to_do, **tail;
1857
1858         if (!revs->topo_order)
1859                 sort_in_topological_order(&revs->commits, revs->lifo);
1860         if (!revs->prune)
1861                 return;
1862
1863         /* feed the list reversed */
1864         yet_to_do = NULL;
1865         for (list = revs->commits; list; list = list->next)
1866                 commit_list_insert(list->item, &yet_to_do);
1867         while (yet_to_do) {
1868                 list = yet_to_do;
1869                 yet_to_do = NULL;
1870                 tail = &yet_to_do;
1871                 while (list) {
1872                         struct commit *commit = list->item;
1873                         struct commit_list *next = list->next;
1874                         free(list);
1875                         list = next;
1876                         tail = simplify_one(revs, commit, tail);
1877                 }
1878         }
1879
1880         /* clean up the result, removing the simplified ones */
1881         list = revs->commits;
1882         revs->commits = NULL;
1883         tail = &revs->commits;
1884         while (list) {
1885                 struct commit *commit = list->item;
1886                 struct commit_list *next = list->next;
1887                 struct merge_simplify_state *st;
1888                 free(list);
1889                 list = next;
1890                 st = locate_simplify_state(revs, commit);
1891                 if (st->simplified == commit)
1892                         tail = &commit_list_insert(commit, tail)->next;
1893         }
1894 }
1895
1896 static void set_children(struct rev_info *revs)
1897 {
1898         struct commit_list *l;
1899         for (l = revs->commits; l; l = l->next) {
1900                 struct commit *commit = l->item;
1901                 struct commit_list *p;
1902
1903                 for (p = commit->parents; p; p = p->next)
1904                         add_child(revs, p->item, commit);
1905         }
1906 }
1907
1908 int prepare_revision_walk(struct rev_info *revs)
1909 {
1910         int nr = revs->pending.nr;
1911         struct object_array_entry *e, *list;
1912
1913         e = list = revs->pending.objects;
1914         revs->pending.nr = 0;
1915         revs->pending.alloc = 0;
1916         revs->pending.objects = NULL;
1917         while (--nr >= 0) {
1918                 struct commit *commit = handle_commit(revs, e->item, e->name);
1919                 if (commit) {
1920                         if (!(commit->object.flags & SEEN)) {
1921                                 commit->object.flags |= SEEN;
1922                                 commit_list_insert_by_date(commit, &revs->commits);
1923                         }
1924                 }
1925                 e++;
1926         }
1927         free(list);
1928
1929         if (revs->no_walk)
1930                 return 0;
1931         if (revs->limited)
1932                 if (limit_list(revs) < 0)
1933                         return -1;
1934         if (revs->topo_order)
1935                 sort_in_topological_order(&revs->commits, revs->lifo);
1936         if (revs->simplify_merges)
1937                 simplify_merges(revs);
1938         if (revs->children.name)
1939                 set_children(revs);
1940         return 0;
1941 }
1942
1943 enum rewrite_result {
1944         rewrite_one_ok,
1945         rewrite_one_noparents,
1946         rewrite_one_error
1947 };
1948
1949 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1950 {
1951         struct commit_list *cache = NULL;
1952
1953         for (;;) {
1954                 struct commit *p = *pp;
1955                 if (!revs->limited)
1956                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1957                                 return rewrite_one_error;
1958                 if (p->parents && p->parents->next)
1959                         return rewrite_one_ok;
1960                 if (p->object.flags & UNINTERESTING)
1961                         return rewrite_one_ok;
1962                 if (!(p->object.flags & TREESAME))
1963                         return rewrite_one_ok;
1964                 if (!p->parents)
1965                         return rewrite_one_noparents;
1966                 *pp = p->parents->item;
1967         }
1968 }
1969
1970 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1971 {
1972         struct commit_list **pp = &commit->parents;
1973         while (*pp) {
1974                 struct commit_list *parent = *pp;
1975                 switch (rewrite_one(revs, &parent->item)) {
1976                 case rewrite_one_ok:
1977                         break;
1978                 case rewrite_one_noparents:
1979                         *pp = parent->next;
1980                         continue;
1981                 case rewrite_one_error:
1982                         return -1;
1983                 }
1984                 pp = &parent->next;
1985         }
1986         remove_duplicate_parents(commit);
1987         return 0;
1988 }
1989
1990 static int commit_match(struct commit *commit, struct rev_info *opt)
1991 {
1992         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
1993                 return 1;
1994         return grep_buffer(&opt->grep_filter,
1995                            NULL, /* we say nothing, not even filename */
1996                            commit->buffer, strlen(commit->buffer));
1997 }
1998
1999 static inline int want_ancestry(struct rev_info *revs)
2000 {
2001         return (revs->rewrite_parents || revs->children.name);
2002 }
2003
2004 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
2005 {
2006         if (commit->object.flags & SHOWN)
2007                 return commit_ignore;
2008         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
2009                 return commit_ignore;
2010         if (revs->show_all)
2011                 return commit_show;
2012         if (commit->object.flags & UNINTERESTING)
2013                 return commit_ignore;
2014         if (revs->min_age != -1 && (commit->date > revs->min_age))
2015                 return commit_ignore;
2016         if (revs->no_merges && commit->parents && commit->parents->next)
2017                 return commit_ignore;
2018         if (revs->merges_only && !(commit->parents && commit->parents->next))
2019                 return commit_ignore;
2020         if (!commit_match(commit, revs))
2021                 return commit_ignore;
2022         if (revs->prune && revs->dense) {
2023                 /* Commit without changes? */
2024                 if (commit->object.flags & TREESAME) {
2025                         /* drop merges unless we want parenthood */
2026                         if (!want_ancestry(revs))
2027                                 return commit_ignore;
2028                         /* non-merge - always ignore it */
2029                         if (!commit->parents || !commit->parents->next)
2030                                 return commit_ignore;
2031                 }
2032         }
2033         return commit_show;
2034 }
2035
2036 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
2037 {
2038         enum commit_action action = get_commit_action(revs, commit);
2039
2040         if (action == commit_show &&
2041             !revs->show_all &&
2042             revs->prune && revs->dense && want_ancestry(revs)) {
2043                 if (rewrite_parents(revs, commit) < 0)
2044                         return commit_error;
2045         }
2046         return action;
2047 }
2048
2049 static struct commit *get_revision_1(struct rev_info *revs)
2050 {
2051         if (!revs->commits)
2052                 return NULL;
2053
2054         do {
2055                 struct commit_list *entry = revs->commits;
2056                 struct commit *commit = entry->item;
2057
2058                 revs->commits = entry->next;
2059                 free(entry);
2060
2061                 if (revs->reflog_info) {
2062                         fake_reflog_parent(revs->reflog_info, commit);
2063                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
2064                 }
2065
2066                 /*
2067                  * If we haven't done the list limiting, we need to look at
2068                  * the parents here. We also need to do the date-based limiting
2069                  * that we'd otherwise have done in limit_list().
2070                  */
2071                 if (!revs->limited) {
2072                         if (revs->max_age != -1 &&
2073                             (commit->date < revs->max_age))
2074                                 continue;
2075                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
2076                                 die("Failed to traverse parents of commit %s",
2077                                     sha1_to_hex(commit->object.sha1));
2078                 }
2079
2080                 switch (simplify_commit(revs, commit)) {
2081                 case commit_ignore:
2082                         continue;
2083                 case commit_error:
2084                         die("Failed to simplify parents of commit %s",
2085                             sha1_to_hex(commit->object.sha1));
2086                 default:
2087                         return commit;
2088                 }
2089         } while (revs->commits);
2090         return NULL;
2091 }
2092
2093 static void gc_boundary(struct object_array *array)
2094 {
2095         unsigned nr = array->nr;
2096         unsigned alloc = array->alloc;
2097         struct object_array_entry *objects = array->objects;
2098
2099         if (alloc <= nr) {
2100                 unsigned i, j;
2101                 for (i = j = 0; i < nr; i++) {
2102                         if (objects[i].item->flags & SHOWN)
2103                                 continue;
2104                         if (i != j)
2105                                 objects[j] = objects[i];
2106                         j++;
2107                 }
2108                 for (i = j; i < nr; i++)
2109                         objects[i].item = NULL;
2110                 array->nr = j;
2111         }
2112 }
2113
2114 static void create_boundary_commit_list(struct rev_info *revs)
2115 {
2116         unsigned i;
2117         struct commit *c;
2118         struct object_array *array = &revs->boundary_commits;
2119         struct object_array_entry *objects = array->objects;
2120
2121         /*
2122          * If revs->commits is non-NULL at this point, an error occurred in
2123          * get_revision_1().  Ignore the error and continue printing the
2124          * boundary commits anyway.  (This is what the code has always
2125          * done.)
2126          */
2127         if (revs->commits) {
2128                 free_commit_list(revs->commits);
2129                 revs->commits = NULL;
2130         }
2131
2132         /*
2133          * Put all of the actual boundary commits from revs->boundary_commits
2134          * into revs->commits
2135          */
2136         for (i = 0; i < array->nr; i++) {
2137                 c = (struct commit *)(objects[i].item);
2138                 if (!c)
2139                         continue;
2140                 if (!(c->object.flags & CHILD_SHOWN))
2141                         continue;
2142                 if (c->object.flags & (SHOWN | BOUNDARY))
2143                         continue;
2144                 c->object.flags |= BOUNDARY;
2145                 commit_list_insert(c, &revs->commits);
2146         }
2147
2148         /*
2149          * If revs->topo_order is set, sort the boundary commits
2150          * in topological order
2151          */
2152         sort_in_topological_order(&revs->commits, revs->lifo);
2153 }
2154
2155 static struct commit *get_revision_internal(struct rev_info *revs)
2156 {
2157         struct commit *c = NULL;
2158         struct commit_list *l;
2159
2160         if (revs->boundary == 2) {
2161                 /*
2162                  * All of the normal commits have already been returned,
2163                  * and we are now returning boundary commits.
2164                  * create_boundary_commit_list() has populated
2165                  * revs->commits with the remaining commits to return.
2166                  */
2167                 c = pop_commit(&revs->commits);
2168                 if (c)
2169                         c->object.flags |= SHOWN;
2170                 return c;
2171         }
2172
2173         /*
2174          * Now pick up what they want to give us
2175          */
2176         c = get_revision_1(revs);
2177         if (c) {
2178                 while (0 < revs->skip_count) {
2179                         revs->skip_count--;
2180                         c = get_revision_1(revs);
2181                         if (!c)
2182                                 break;
2183                 }
2184         }
2185
2186         /*
2187          * Check the max_count.
2188          */
2189         switch (revs->max_count) {
2190         case -1:
2191                 break;
2192         case 0:
2193                 c = NULL;
2194                 break;
2195         default:
2196                 revs->max_count--;
2197         }
2198
2199         if (c)
2200                 c->object.flags |= SHOWN;
2201
2202         if (!revs->boundary) {
2203                 return c;
2204         }
2205
2206         if (!c) {
2207                 /*
2208                  * get_revision_1() runs out the commits, and
2209                  * we are done computing the boundaries.
2210                  * switch to boundary commits output mode.
2211                  */
2212                 revs->boundary = 2;
2213
2214                 /*
2215                  * Update revs->commits to contain the list of
2216                  * boundary commits.
2217                  */
2218                 create_boundary_commit_list(revs);
2219
2220                 return get_revision_internal(revs);
2221         }
2222
2223         /*
2224          * boundary commits are the commits that are parents of the
2225          * ones we got from get_revision_1() but they themselves are
2226          * not returned from get_revision_1().  Before returning
2227          * 'c', we need to mark its parents that they could be boundaries.
2228          */
2229
2230         for (l = c->parents; l; l = l->next) {
2231                 struct object *p;
2232                 p = &(l->item->object);
2233                 if (p->flags & (CHILD_SHOWN | SHOWN))
2234                         continue;
2235                 p->flags |= CHILD_SHOWN;
2236                 gc_boundary(&revs->boundary_commits);
2237                 add_object_array(p, NULL, &revs->boundary_commits);
2238         }
2239
2240         return c;
2241 }
2242
2243 struct commit *get_revision(struct rev_info *revs)
2244 {
2245         struct commit *c;
2246         struct commit_list *reversed;
2247
2248         if (revs->reverse) {
2249                 reversed = NULL;
2250                 while ((c = get_revision_internal(revs))) {
2251                         commit_list_insert(c, &reversed);
2252                 }
2253                 revs->commits = reversed;
2254                 revs->reverse = 0;
2255                 revs->reverse_output_stage = 1;
2256         }
2257
2258         if (revs->reverse_output_stage)
2259                 return pop_commit(&revs->commits);
2260
2261         c = get_revision_internal(revs);
2262         if (c && revs->graph)
2263                 graph_update(revs->graph, c);
2264         return c;
2265 }