Merge branch 'jn/test-terminal-punt-on-osx-breakage' into maint
[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 static int limit_list(struct rev_info *revs)
737 {
738         int slop = SLOP;
739         unsigned long date = ~0ul;
740         struct commit_list *list = revs->commits;
741         struct commit_list *newlist = NULL;
742         struct commit_list **p = &newlist;
743         struct commit_list *bottom = NULL;
744
745         if (revs->ancestry_path) {
746                 bottom = collect_bottom_commits(list);
747                 if (!bottom)
748                         die("--ancestry-path given but there are no bottom commits");
749         }
750
751         while (list) {
752                 struct commit_list *entry = list;
753                 struct commit *commit = list->item;
754                 struct object *obj = &commit->object;
755                 show_early_output_fn_t show;
756
757                 list = list->next;
758                 free(entry);
759
760                 if (revs->max_age != -1 && (commit->date < revs->max_age))
761                         obj->flags |= UNINTERESTING;
762                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
763                         return -1;
764                 if (obj->flags & UNINTERESTING) {
765                         mark_parents_uninteresting(commit);
766                         if (revs->show_all)
767                                 p = &commit_list_insert(commit, p)->next;
768                         slop = still_interesting(list, date, slop);
769                         if (slop)
770                                 continue;
771                         /* If showing all, add the whole pending list to the end */
772                         if (revs->show_all)
773                                 *p = list;
774                         break;
775                 }
776                 if (revs->min_age != -1 && (commit->date > revs->min_age))
777                         continue;
778                 date = commit->date;
779                 p = &commit_list_insert(commit, p)->next;
780
781                 show = show_early_output;
782                 if (!show)
783                         continue;
784
785                 show(revs, newlist);
786                 show_early_output = NULL;
787         }
788         if (revs->cherry_pick)
789                 cherry_pick_list(newlist, revs);
790
791         if (bottom) {
792                 limit_to_ancestry(bottom, newlist);
793                 free_commit_list(bottom);
794         }
795
796         revs->commits = newlist;
797         return 0;
798 }
799
800 struct all_refs_cb {
801         int all_flags;
802         int warned_bad_reflog;
803         struct rev_info *all_revs;
804         const char *name_for_errormsg;
805 };
806
807 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
808 {
809         struct all_refs_cb *cb = cb_data;
810         struct object *object = get_reference(cb->all_revs, path, sha1,
811                                               cb->all_flags);
812         add_pending_object(cb->all_revs, object, path);
813         return 0;
814 }
815
816 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
817         unsigned flags)
818 {
819         cb->all_revs = revs;
820         cb->all_flags = flags;
821 }
822
823 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
824                 int (*for_each)(const char *, each_ref_fn, void *))
825 {
826         struct all_refs_cb cb;
827         init_all_refs_cb(&cb, revs, flags);
828         for_each(submodule, handle_one_ref, &cb);
829 }
830
831 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
832 {
833         struct all_refs_cb *cb = cb_data;
834         if (!is_null_sha1(sha1)) {
835                 struct object *o = parse_object(sha1);
836                 if (o) {
837                         o->flags |= cb->all_flags;
838                         add_pending_object(cb->all_revs, o, "");
839                 }
840                 else if (!cb->warned_bad_reflog) {
841                         warning("reflog of '%s' references pruned commits",
842                                 cb->name_for_errormsg);
843                         cb->warned_bad_reflog = 1;
844                 }
845         }
846 }
847
848 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
849                 const char *email, unsigned long timestamp, int tz,
850                 const char *message, void *cb_data)
851 {
852         handle_one_reflog_commit(osha1, cb_data);
853         handle_one_reflog_commit(nsha1, cb_data);
854         return 0;
855 }
856
857 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
858 {
859         struct all_refs_cb *cb = cb_data;
860         cb->warned_bad_reflog = 0;
861         cb->name_for_errormsg = path;
862         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
863         return 0;
864 }
865
866 static void handle_reflog(struct rev_info *revs, unsigned flags)
867 {
868         struct all_refs_cb cb;
869         cb.all_revs = revs;
870         cb.all_flags = flags;
871         for_each_reflog(handle_one_reflog, &cb);
872 }
873
874 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
875 {
876         unsigned char sha1[20];
877         struct object *it;
878         struct commit *commit;
879         struct commit_list *parents;
880
881         if (*arg == '^') {
882                 flags ^= UNINTERESTING;
883                 arg++;
884         }
885         if (get_sha1(arg, sha1))
886                 return 0;
887         while (1) {
888                 it = get_reference(revs, arg, sha1, 0);
889                 if (it->type != OBJ_TAG)
890                         break;
891                 if (!((struct tag*)it)->tagged)
892                         return 0;
893                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
894         }
895         if (it->type != OBJ_COMMIT)
896                 return 0;
897         commit = (struct commit *)it;
898         for (parents = commit->parents; parents; parents = parents->next) {
899                 it = &parents->item->object;
900                 it->flags |= flags;
901                 add_pending_object(revs, it, arg);
902         }
903         return 1;
904 }
905
906 void init_revisions(struct rev_info *revs, const char *prefix)
907 {
908         memset(revs, 0, sizeof(*revs));
909
910         revs->abbrev = DEFAULT_ABBREV;
911         revs->ignore_merges = 1;
912         revs->simplify_history = 1;
913         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
914         DIFF_OPT_SET(&revs->pruning, QUICK);
915         revs->pruning.add_remove = file_add_remove;
916         revs->pruning.change = file_change;
917         revs->lifo = 1;
918         revs->dense = 1;
919         revs->prefix = prefix;
920         revs->max_age = -1;
921         revs->min_age = -1;
922         revs->skip_count = -1;
923         revs->max_count = -1;
924
925         revs->commit_format = CMIT_FMT_DEFAULT;
926
927         revs->grep_filter.status_only = 1;
928         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
929         revs->grep_filter.header_tail = &(revs->grep_filter.header_list);
930         revs->grep_filter.regflags = REG_NEWLINE;
931
932         diff_setup(&revs->diffopt);
933         if (prefix && !revs->diffopt.prefix) {
934                 revs->diffopt.prefix = prefix;
935                 revs->diffopt.prefix_length = strlen(prefix);
936         }
937 }
938
939 static void add_pending_commit_list(struct rev_info *revs,
940                                     struct commit_list *commit_list,
941                                     unsigned int flags)
942 {
943         while (commit_list) {
944                 struct object *object = &commit_list->item->object;
945                 object->flags |= flags;
946                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
947                 commit_list = commit_list->next;
948         }
949 }
950
951 static void prepare_show_merge(struct rev_info *revs)
952 {
953         struct commit_list *bases;
954         struct commit *head, *other;
955         unsigned char sha1[20];
956         const char **prune = NULL;
957         int i, prune_num = 1; /* counting terminating NULL */
958
959         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
960                 die("--merge without HEAD?");
961         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
962                 die("--merge without MERGE_HEAD?");
963         add_pending_object(revs, &head->object, "HEAD");
964         add_pending_object(revs, &other->object, "MERGE_HEAD");
965         bases = get_merge_bases(head, other, 1);
966         add_pending_commit_list(revs, bases, UNINTERESTING);
967         free_commit_list(bases);
968         head->object.flags |= SYMMETRIC_LEFT;
969
970         if (!active_nr)
971                 read_cache();
972         for (i = 0; i < active_nr; i++) {
973                 struct cache_entry *ce = active_cache[i];
974                 if (!ce_stage(ce))
975                         continue;
976                 if (ce_path_match(ce, revs->prune_data)) {
977                         prune_num++;
978                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
979                         prune[prune_num-2] = ce->name;
980                         prune[prune_num-1] = NULL;
981                 }
982                 while ((i+1 < active_nr) &&
983                        ce_same_name(ce, active_cache[i+1]))
984                         i++;
985         }
986         revs->prune_data = prune;
987         revs->limited = 1;
988 }
989
990 int handle_revision_arg(const char *arg, struct rev_info *revs,
991                         int flags,
992                         int cant_be_filename)
993 {
994         unsigned mode;
995         char *dotdot;
996         struct object *object;
997         unsigned char sha1[20];
998         int local_flags;
999
1000         dotdot = strstr(arg, "..");
1001         if (dotdot) {
1002                 unsigned char from_sha1[20];
1003                 const char *next = dotdot + 2;
1004                 const char *this = arg;
1005                 int symmetric = *next == '.';
1006                 unsigned int flags_exclude = flags ^ UNINTERESTING;
1007
1008                 *dotdot = 0;
1009                 next += symmetric;
1010
1011                 if (!*next)
1012                         next = "HEAD";
1013                 if (dotdot == arg)
1014                         this = "HEAD";
1015                 if (!get_sha1(this, from_sha1) &&
1016                     !get_sha1(next, sha1)) {
1017                         struct commit *a, *b;
1018                         struct commit_list *exclude;
1019
1020                         a = lookup_commit_reference(from_sha1);
1021                         b = lookup_commit_reference(sha1);
1022                         if (!a || !b) {
1023                                 die(symmetric ?
1024                                     "Invalid symmetric difference expression %s...%s" :
1025                                     "Invalid revision range %s..%s",
1026                                     arg, next);
1027                         }
1028
1029                         if (!cant_be_filename) {
1030                                 *dotdot = '.';
1031                                 verify_non_filename(revs->prefix, arg);
1032                         }
1033
1034                         if (symmetric) {
1035                                 exclude = get_merge_bases(a, b, 1);
1036                                 add_pending_commit_list(revs, exclude,
1037                                                         flags_exclude);
1038                                 free_commit_list(exclude);
1039                                 a->object.flags |= flags | SYMMETRIC_LEFT;
1040                         } else
1041                                 a->object.flags |= flags_exclude;
1042                         b->object.flags |= flags;
1043                         add_pending_object(revs, &a->object, this);
1044                         add_pending_object(revs, &b->object, next);
1045                         return 0;
1046                 }
1047                 *dotdot = '.';
1048         }
1049         dotdot = strstr(arg, "^@");
1050         if (dotdot && !dotdot[2]) {
1051                 *dotdot = 0;
1052                 if (add_parents_only(revs, arg, flags))
1053                         return 0;
1054                 *dotdot = '^';
1055         }
1056         dotdot = strstr(arg, "^!");
1057         if (dotdot && !dotdot[2]) {
1058                 *dotdot = 0;
1059                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
1060                         *dotdot = '^';
1061         }
1062
1063         local_flags = 0;
1064         if (*arg == '^') {
1065                 local_flags = UNINTERESTING;
1066                 arg++;
1067         }
1068         if (get_sha1_with_mode(arg, sha1, &mode))
1069                 return -1;
1070         if (!cant_be_filename)
1071                 verify_non_filename(revs->prefix, arg);
1072         object = get_reference(revs, arg, sha1, flags ^ local_flags);
1073         add_pending_object_with_mode(revs, object, arg, mode);
1074         return 0;
1075 }
1076
1077 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb, const char ***prune_data)
1078 {
1079         const char **prune = *prune_data;
1080         int prune_nr;
1081         int prune_alloc;
1082
1083         /* count existing ones */
1084         if (!prune)
1085                 prune_nr = 0;
1086         else
1087                 for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1088                         ;
1089         prune_alloc = prune_nr; /* not really, but we do not know */
1090
1091         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
1092                 int len = sb->len;
1093                 if (len && sb->buf[len - 1] == '\n')
1094                         sb->buf[--len] = '\0';
1095                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1096                 prune[prune_nr++] = xstrdup(sb->buf);
1097         }
1098         if (prune) {
1099                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1100                 prune[prune_nr] = NULL;
1101         }
1102         *prune_data = prune;
1103 }
1104
1105 static void read_revisions_from_stdin(struct rev_info *revs, const char ***prune)
1106 {
1107         struct strbuf sb;
1108         int seen_dashdash = 0;
1109
1110         strbuf_init(&sb, 1000);
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                 if (!len)
1116                         break;
1117                 if (sb.buf[0] == '-') {
1118                         if (len == 2 && sb.buf[1] == '-') {
1119                                 seen_dashdash = 1;
1120                                 break;
1121                         }
1122                         die("options not supported in --stdin mode");
1123                 }
1124                 if (handle_revision_arg(sb.buf, revs, 0, 1))
1125                         die("bad revision '%s'", sb.buf);
1126         }
1127         if (seen_dashdash)
1128                 read_pathspec_from_stdin(revs, &sb, prune);
1129         strbuf_release(&sb);
1130 }
1131
1132 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1133 {
1134         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1135 }
1136
1137 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1138 {
1139         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1140 }
1141
1142 static void add_message_grep(struct rev_info *revs, const char *pattern)
1143 {
1144         add_grep(revs, pattern, GREP_PATTERN_BODY);
1145 }
1146
1147 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1148                                int *unkc, const char **unkv)
1149 {
1150         const char *arg = argv[0];
1151         const char *optarg;
1152         int argcount;
1153
1154         /* pseudo revision arguments */
1155         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1156             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1157             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1158             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1159             !strcmp(arg, "--bisect"))
1160         {
1161                 unkv[(*unkc)++] = arg;
1162                 return 1;
1163         }
1164
1165         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1166                 revs->max_count = atoi(optarg);
1167                 revs->no_walk = 0;
1168                 return argcount;
1169         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1170                 revs->skip_count = atoi(optarg);
1171                 return argcount;
1172         } else if ((*arg == '-') && isdigit(arg[1])) {
1173         /* accept -<digit>, like traditional "head" */
1174                 revs->max_count = atoi(arg + 1);
1175                 revs->no_walk = 0;
1176         } else if (!strcmp(arg, "-n")) {
1177                 if (argc <= 1)
1178                         return error("-n requires an argument");
1179                 revs->max_count = atoi(argv[1]);
1180                 revs->no_walk = 0;
1181                 return 2;
1182         } else if (!prefixcmp(arg, "-n")) {
1183                 revs->max_count = atoi(arg + 2);
1184                 revs->no_walk = 0;
1185         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1186                 revs->max_age = atoi(optarg);
1187                 return argcount;
1188         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1189                 revs->max_age = approxidate(optarg);
1190                 return argcount;
1191         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1192                 revs->max_age = approxidate(optarg);
1193                 return argcount;
1194         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1195                 revs->min_age = atoi(optarg);
1196                 return argcount;
1197         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1198                 revs->min_age = approxidate(optarg);
1199                 return argcount;
1200         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1201                 revs->min_age = approxidate(optarg);
1202                 return argcount;
1203         } else if (!strcmp(arg, "--first-parent")) {
1204                 revs->first_parent_only = 1;
1205         } else if (!strcmp(arg, "--ancestry-path")) {
1206                 revs->ancestry_path = 1;
1207                 revs->simplify_history = 0;
1208                 revs->limited = 1;
1209         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1210                 init_reflog_walk(&revs->reflog_info);
1211         } else if (!strcmp(arg, "--default")) {
1212                 if (argc <= 1)
1213                         return error("bad --default argument");
1214                 revs->def = argv[1];
1215                 return 2;
1216         } else if (!strcmp(arg, "--merge")) {
1217                 revs->show_merge = 1;
1218         } else if (!strcmp(arg, "--topo-order")) {
1219                 revs->lifo = 1;
1220                 revs->topo_order = 1;
1221         } else if (!strcmp(arg, "--simplify-merges")) {
1222                 revs->simplify_merges = 1;
1223                 revs->rewrite_parents = 1;
1224                 revs->simplify_history = 0;
1225                 revs->limited = 1;
1226         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1227                 revs->simplify_merges = 1;
1228                 revs->rewrite_parents = 1;
1229                 revs->simplify_history = 0;
1230                 revs->simplify_by_decoration = 1;
1231                 revs->limited = 1;
1232                 revs->prune = 1;
1233                 load_ref_decorations(DECORATE_SHORT_REFS);
1234         } else if (!strcmp(arg, "--date-order")) {
1235                 revs->lifo = 0;
1236                 revs->topo_order = 1;
1237         } else if (!prefixcmp(arg, "--early-output")) {
1238                 int count = 100;
1239                 switch (arg[14]) {
1240                 case '=':
1241                         count = atoi(arg+15);
1242                         /* Fallthrough */
1243                 case 0:
1244                         revs->topo_order = 1;
1245                        revs->early_output = count;
1246                 }
1247         } else if (!strcmp(arg, "--parents")) {
1248                 revs->rewrite_parents = 1;
1249                 revs->print_parents = 1;
1250         } else if (!strcmp(arg, "--dense")) {
1251                 revs->dense = 1;
1252         } else if (!strcmp(arg, "--sparse")) {
1253                 revs->dense = 0;
1254         } else if (!strcmp(arg, "--show-all")) {
1255                 revs->show_all = 1;
1256         } else if (!strcmp(arg, "--remove-empty")) {
1257                 revs->remove_empty_trees = 1;
1258         } else if (!strcmp(arg, "--merges")) {
1259                 revs->merges_only = 1;
1260         } else if (!strcmp(arg, "--no-merges")) {
1261                 revs->no_merges = 1;
1262         } else if (!strcmp(arg, "--boundary")) {
1263                 revs->boundary = 1;
1264         } else if (!strcmp(arg, "--left-right")) {
1265                 revs->left_right = 1;
1266         } else if (!strcmp(arg, "--count")) {
1267                 revs->count = 1;
1268         } else if (!strcmp(arg, "--cherry-pick")) {
1269                 revs->cherry_pick = 1;
1270                 revs->limited = 1;
1271         } else if (!strcmp(arg, "--objects")) {
1272                 revs->tag_objects = 1;
1273                 revs->tree_objects = 1;
1274                 revs->blob_objects = 1;
1275         } else if (!strcmp(arg, "--objects-edge")) {
1276                 revs->tag_objects = 1;
1277                 revs->tree_objects = 1;
1278                 revs->blob_objects = 1;
1279                 revs->edge_hint = 1;
1280         } else if (!strcmp(arg, "--unpacked")) {
1281                 revs->unpacked = 1;
1282         } else if (!prefixcmp(arg, "--unpacked=")) {
1283                 die("--unpacked=<packfile> no longer supported.");
1284         } else if (!strcmp(arg, "-r")) {
1285                 revs->diff = 1;
1286                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1287         } else if (!strcmp(arg, "-t")) {
1288                 revs->diff = 1;
1289                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1290                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1291         } else if (!strcmp(arg, "-m")) {
1292                 revs->ignore_merges = 0;
1293         } else if (!strcmp(arg, "-c")) {
1294                 revs->diff = 1;
1295                 revs->dense_combined_merges = 0;
1296                 revs->combine_merges = 1;
1297         } else if (!strcmp(arg, "--cc")) {
1298                 revs->diff = 1;
1299                 revs->dense_combined_merges = 1;
1300                 revs->combine_merges = 1;
1301         } else if (!strcmp(arg, "-v")) {
1302                 revs->verbose_header = 1;
1303         } else if (!strcmp(arg, "--pretty")) {
1304                 revs->verbose_header = 1;
1305                 revs->pretty_given = 1;
1306                 get_commit_format(arg+8, revs);
1307         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1308                 /*
1309                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1310                  * not allowed, since the argument is optional.
1311                  */
1312                 revs->verbose_header = 1;
1313                 revs->pretty_given = 1;
1314                 get_commit_format(arg+9, revs);
1315         } else if (!strcmp(arg, "--show-notes")) {
1316                 revs->show_notes = 1;
1317                 revs->show_notes_given = 1;
1318         } else if (!prefixcmp(arg, "--show-notes=")) {
1319                 struct strbuf buf = STRBUF_INIT;
1320                 revs->show_notes = 1;
1321                 revs->show_notes_given = 1;
1322                 if (!revs->notes_opt.extra_notes_refs)
1323                         revs->notes_opt.extra_notes_refs = xcalloc(1, sizeof(struct string_list));
1324                 if (!prefixcmp(arg+13, "refs/"))
1325                         /* happy */;
1326                 else if (!prefixcmp(arg+13, "notes/"))
1327                         strbuf_addstr(&buf, "refs/");
1328                 else
1329                         strbuf_addstr(&buf, "refs/notes/");
1330                 strbuf_addstr(&buf, arg+13);
1331                 string_list_append(revs->notes_opt.extra_notes_refs,
1332                                    strbuf_detach(&buf, NULL));
1333         } else if (!strcmp(arg, "--no-notes")) {
1334                 revs->show_notes = 0;
1335                 revs->show_notes_given = 1;
1336         } else if (!strcmp(arg, "--standard-notes")) {
1337                 revs->show_notes_given = 1;
1338                 revs->notes_opt.suppress_default_notes = 0;
1339         } else if (!strcmp(arg, "--no-standard-notes")) {
1340                 revs->notes_opt.suppress_default_notes = 1;
1341         } else if (!strcmp(arg, "--oneline")) {
1342                 revs->verbose_header = 1;
1343                 get_commit_format("oneline", revs);
1344                 revs->pretty_given = 1;
1345                 revs->abbrev_commit = 1;
1346         } else if (!strcmp(arg, "--graph")) {
1347                 revs->topo_order = 1;
1348                 revs->rewrite_parents = 1;
1349                 revs->graph = graph_init(revs);
1350         } else if (!strcmp(arg, "--root")) {
1351                 revs->show_root_diff = 1;
1352         } else if (!strcmp(arg, "--no-commit-id")) {
1353                 revs->no_commit_id = 1;
1354         } else if (!strcmp(arg, "--always")) {
1355                 revs->always_show_header = 1;
1356         } else if (!strcmp(arg, "--no-abbrev")) {
1357                 revs->abbrev = 0;
1358         } else if (!strcmp(arg, "--abbrev")) {
1359                 revs->abbrev = DEFAULT_ABBREV;
1360         } else if (!prefixcmp(arg, "--abbrev=")) {
1361                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1362                 if (revs->abbrev < MINIMUM_ABBREV)
1363                         revs->abbrev = MINIMUM_ABBREV;
1364                 else if (revs->abbrev > 40)
1365                         revs->abbrev = 40;
1366         } else if (!strcmp(arg, "--abbrev-commit")) {
1367                 revs->abbrev_commit = 1;
1368         } else if (!strcmp(arg, "--full-diff")) {
1369                 revs->diff = 1;
1370                 revs->full_diff = 1;
1371         } else if (!strcmp(arg, "--full-history")) {
1372                 revs->simplify_history = 0;
1373         } else if (!strcmp(arg, "--relative-date")) {
1374                 revs->date_mode = DATE_RELATIVE;
1375                 revs->date_mode_explicit = 1;
1376         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
1377                 revs->date_mode = parse_date_format(optarg);
1378                 revs->date_mode_explicit = 1;
1379                 return argcount;
1380         } else if (!strcmp(arg, "--log-size")) {
1381                 revs->show_log_size = 1;
1382         }
1383         /*
1384          * Grepping the commit log
1385          */
1386         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
1387                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
1388                 return argcount;
1389         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
1390                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
1391                 return argcount;
1392         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
1393                 add_message_grep(revs, optarg);
1394                 return argcount;
1395         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1396                 revs->grep_filter.regflags |= REG_EXTENDED;
1397         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1398                 revs->grep_filter.regflags |= REG_ICASE;
1399         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1400                 revs->grep_filter.fixed = 1;
1401         } else if (!strcmp(arg, "--all-match")) {
1402                 revs->grep_filter.all_match = 1;
1403         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
1404                 if (strcmp(optarg, "none"))
1405                         git_log_output_encoding = xstrdup(optarg);
1406                 else
1407                         git_log_output_encoding = "";
1408                 return argcount;
1409         } else if (!strcmp(arg, "--reverse")) {
1410                 revs->reverse ^= 1;
1411         } else if (!strcmp(arg, "--children")) {
1412                 revs->children.name = "children";
1413                 revs->limited = 1;
1414         } else {
1415                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1416                 if (!opts)
1417                         unkv[(*unkc)++] = arg;
1418                 return opts;
1419         }
1420
1421         return 1;
1422 }
1423
1424 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1425                         const struct option *options,
1426                         const char * const usagestr[])
1427 {
1428         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1429                                     &ctx->cpidx, ctx->out);
1430         if (n <= 0) {
1431                 error("unknown option `%s'", ctx->argv[0]);
1432                 usage_with_options(usagestr, options);
1433         }
1434         ctx->argv += n;
1435         ctx->argc -= n;
1436 }
1437
1438 static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1439 {
1440         return for_each_ref_in_submodule(submodule, "refs/bisect/bad", fn, cb_data);
1441 }
1442
1443 static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1444 {
1445         return for_each_ref_in_submodule(submodule, "refs/bisect/good", fn, cb_data);
1446 }
1447
1448 static void append_prune_data(const char ***prune_data, const char **av)
1449 {
1450         const char **prune = *prune_data;
1451         int prune_nr;
1452         int prune_alloc;
1453
1454         if (!prune) {
1455                 *prune_data = av;
1456                 return;
1457         }
1458
1459         /* count existing ones */
1460         for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1461                 ;
1462         prune_alloc = prune_nr; /* not really, but we do not know */
1463
1464         while (*av) {
1465                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1466                 prune[prune_nr++] = *av;
1467                 av++;
1468         }
1469         if (prune) {
1470                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1471                 prune[prune_nr] = NULL;
1472         }
1473         *prune_data = prune;
1474 }
1475
1476 /*
1477  * Parse revision information, filling in the "rev_info" structure,
1478  * and removing the used arguments from the argument list.
1479  *
1480  * Returns the number of arguments left that weren't recognized
1481  * (which are also moved to the head of the argument list)
1482  */
1483 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
1484 {
1485         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0;
1486         const char **prune_data = NULL;
1487         const char *submodule = NULL;
1488         const char *optarg;
1489         int argcount;
1490
1491         if (opt)
1492                 submodule = opt->submodule;
1493
1494         /* First, search for "--" */
1495         seen_dashdash = 0;
1496         for (i = 1; i < argc; i++) {
1497                 const char *arg = argv[i];
1498                 if (strcmp(arg, "--"))
1499                         continue;
1500                 argv[i] = NULL;
1501                 argc = i;
1502                 if (argv[i + 1])
1503                         prune_data = argv + i + 1;
1504                 seen_dashdash = 1;
1505                 break;
1506         }
1507
1508         /* Second, deal with arguments and options */
1509         flags = 0;
1510         read_from_stdin = 0;
1511         for (left = i = 1; i < argc; i++) {
1512                 const char *arg = argv[i];
1513                 if (*arg == '-') {
1514                         int opts;
1515
1516                         if (!strcmp(arg, "--all")) {
1517                                 handle_refs(submodule, revs, flags, for_each_ref_submodule);
1518                                 handle_refs(submodule, revs, flags, head_ref_submodule);
1519                                 continue;
1520                         }
1521                         if (!strcmp(arg, "--branches")) {
1522                                 handle_refs(submodule, revs, flags, for_each_branch_ref_submodule);
1523                                 continue;
1524                         }
1525                         if (!strcmp(arg, "--bisect")) {
1526                                 handle_refs(submodule, revs, flags, for_each_bad_bisect_ref);
1527                                 handle_refs(submodule, revs, flags ^ UNINTERESTING, for_each_good_bisect_ref);
1528                                 revs->bisect = 1;
1529                                 continue;
1530                         }
1531                         if (!strcmp(arg, "--tags")) {
1532                                 handle_refs(submodule, revs, flags, for_each_tag_ref_submodule);
1533                                 continue;
1534                         }
1535                         if (!strcmp(arg, "--remotes")) {
1536                                 handle_refs(submodule, revs, flags, for_each_remote_ref_submodule);
1537                                 continue;
1538                         }
1539                         if ((argcount = parse_long_opt("glob", argv + i, &optarg))) {
1540                                 struct all_refs_cb cb;
1541                                 i += argcount - 1;
1542                                 init_all_refs_cb(&cb, revs, flags);
1543                                 for_each_glob_ref(handle_one_ref, optarg, &cb);
1544                                 continue;
1545                         }
1546                         if (!prefixcmp(arg, "--branches=")) {
1547                                 struct all_refs_cb cb;
1548                                 init_all_refs_cb(&cb, revs, flags);
1549                                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
1550                                 continue;
1551                         }
1552                         if (!prefixcmp(arg, "--tags=")) {
1553                                 struct all_refs_cb cb;
1554                                 init_all_refs_cb(&cb, revs, flags);
1555                                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
1556                                 continue;
1557                         }
1558                         if (!prefixcmp(arg, "--remotes=")) {
1559                                 struct all_refs_cb cb;
1560                                 init_all_refs_cb(&cb, revs, flags);
1561                                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
1562                                 continue;
1563                         }
1564                         if (!strcmp(arg, "--reflog")) {
1565                                 handle_reflog(revs, flags);
1566                                 continue;
1567                         }
1568                         if (!strcmp(arg, "--not")) {
1569                                 flags ^= UNINTERESTING;
1570                                 continue;
1571                         }
1572                         if (!strcmp(arg, "--no-walk")) {
1573                                 revs->no_walk = 1;
1574                                 continue;
1575                         }
1576                         if (!strcmp(arg, "--do-walk")) {
1577                                 revs->no_walk = 0;
1578                                 continue;
1579                         }
1580                         if (!strcmp(arg, "--stdin")) {
1581                                 if (revs->disable_stdin) {
1582                                         argv[left++] = arg;
1583                                         continue;
1584                                 }
1585                                 if (read_from_stdin++)
1586                                         die("--stdin given twice?");
1587                                 read_revisions_from_stdin(revs, &prune_data);
1588                                 continue;
1589                         }
1590
1591                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1592                         if (opts > 0) {
1593                                 i += opts - 1;
1594                                 continue;
1595                         }
1596                         if (opts < 0)
1597                                 exit(128);
1598                         continue;
1599                 }
1600
1601                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1602                         int j;
1603                         if (seen_dashdash || *arg == '^')
1604                                 die("bad revision '%s'", arg);
1605
1606                         /* If we didn't have a "--":
1607                          * (1) all filenames must exist;
1608                          * (2) all rev-args must not be interpretable
1609                          *     as a valid filename.
1610                          * but the latter we have checked in the main loop.
1611                          */
1612                         for (j = i; j < argc; j++)
1613                                 verify_filename(revs->prefix, argv[j]);
1614
1615                         append_prune_data(&prune_data, argv + i);
1616                         break;
1617                 }
1618                 else
1619                         got_rev_arg = 1;
1620         }
1621
1622         if (prune_data)
1623                 revs->prune_data = get_pathspec(revs->prefix, prune_data);
1624
1625         if (revs->def == NULL)
1626                 revs->def = opt ? opt->def : NULL;
1627         if (opt && opt->tweak)
1628                 opt->tweak(revs, opt);
1629         if (revs->show_merge)
1630                 prepare_show_merge(revs);
1631         if (revs->def && !revs->pending.nr && !got_rev_arg) {
1632                 unsigned char sha1[20];
1633                 struct object *object;
1634                 unsigned mode;
1635                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1636                         die("bad default revision '%s'", revs->def);
1637                 object = get_reference(revs, revs->def, sha1, 0);
1638                 add_pending_object_with_mode(revs, object, revs->def, mode);
1639         }
1640
1641         /* Did the user ask for any diff output? Run the diff! */
1642         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1643                 revs->diff = 1;
1644
1645         /* Pickaxe, diff-filter and rename following need diffs */
1646         if (revs->diffopt.pickaxe ||
1647             revs->diffopt.filter ||
1648             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1649                 revs->diff = 1;
1650
1651         if (revs->topo_order)
1652                 revs->limited = 1;
1653
1654         if (revs->prune_data) {
1655                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1656                 /* Can't prune commits with rename following: the paths change.. */
1657                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1658                         revs->prune = 1;
1659                 if (!revs->full_diff)
1660                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1661         }
1662         if (revs->combine_merges)
1663                 revs->ignore_merges = 0;
1664         revs->diffopt.abbrev = revs->abbrev;
1665         if (diff_setup_done(&revs->diffopt) < 0)
1666                 die("diff_setup_done failed");
1667
1668         compile_grep_patterns(&revs->grep_filter);
1669
1670         if (revs->reverse && revs->reflog_info)
1671                 die("cannot combine --reverse with --walk-reflogs");
1672         if (revs->rewrite_parents && revs->children.name)
1673                 die("cannot combine --parents and --children");
1674
1675         /*
1676          * Limitations on the graph functionality
1677          */
1678         if (revs->reverse && revs->graph)
1679                 die("cannot combine --reverse with --graph");
1680
1681         if (revs->reflog_info && revs->graph)
1682                 die("cannot combine --walk-reflogs with --graph");
1683
1684         return left;
1685 }
1686
1687 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1688 {
1689         struct commit_list *l = xcalloc(1, sizeof(*l));
1690
1691         l->item = child;
1692         l->next = add_decoration(&revs->children, &parent->object, l);
1693 }
1694
1695 static int remove_duplicate_parents(struct commit *commit)
1696 {
1697         struct commit_list **pp, *p;
1698         int surviving_parents;
1699
1700         /* Examine existing parents while marking ones we have seen... */
1701         pp = &commit->parents;
1702         while ((p = *pp) != NULL) {
1703                 struct commit *parent = p->item;
1704                 if (parent->object.flags & TMP_MARK) {
1705                         *pp = p->next;
1706                         continue;
1707                 }
1708                 parent->object.flags |= TMP_MARK;
1709                 pp = &p->next;
1710         }
1711         /* count them while clearing the temporary mark */
1712         surviving_parents = 0;
1713         for (p = commit->parents; p; p = p->next) {
1714                 p->item->object.flags &= ~TMP_MARK;
1715                 surviving_parents++;
1716         }
1717         return surviving_parents;
1718 }
1719
1720 struct merge_simplify_state {
1721         struct commit *simplified;
1722 };
1723
1724 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1725 {
1726         struct merge_simplify_state *st;
1727
1728         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1729         if (!st) {
1730                 st = xcalloc(1, sizeof(*st));
1731                 add_decoration(&revs->merge_simplification, &commit->object, st);
1732         }
1733         return st;
1734 }
1735
1736 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1737 {
1738         struct commit_list *p;
1739         struct merge_simplify_state *st, *pst;
1740         int cnt;
1741
1742         st = locate_simplify_state(revs, commit);
1743
1744         /*
1745          * Have we handled this one?
1746          */
1747         if (st->simplified)
1748                 return tail;
1749
1750         /*
1751          * An UNINTERESTING commit simplifies to itself, so does a
1752          * root commit.  We do not rewrite parents of such commit
1753          * anyway.
1754          */
1755         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1756                 st->simplified = commit;
1757                 return tail;
1758         }
1759
1760         /*
1761          * Do we know what commit all of our parents should be rewritten to?
1762          * Otherwise we are not ready to rewrite this one yet.
1763          */
1764         for (cnt = 0, p = commit->parents; p; p = p->next) {
1765                 pst = locate_simplify_state(revs, p->item);
1766                 if (!pst->simplified) {
1767                         tail = &commit_list_insert(p->item, tail)->next;
1768                         cnt++;
1769                 }
1770         }
1771         if (cnt) {
1772                 tail = &commit_list_insert(commit, tail)->next;
1773                 return tail;
1774         }
1775
1776         /*
1777          * Rewrite our list of parents.
1778          */
1779         for (p = commit->parents; p; p = p->next) {
1780                 pst = locate_simplify_state(revs, p->item);
1781                 p->item = pst->simplified;
1782         }
1783         cnt = remove_duplicate_parents(commit);
1784
1785         /*
1786          * It is possible that we are a merge and one side branch
1787          * does not have any commit that touches the given paths;
1788          * in such a case, the immediate parents will be rewritten
1789          * to different commits.
1790          *
1791          *      o----X          X: the commit we are looking at;
1792          *     /    /           o: a commit that touches the paths;
1793          * ---o----'
1794          *
1795          * Further reduce the parents by removing redundant parents.
1796          */
1797         if (1 < cnt) {
1798                 struct commit_list *h = reduce_heads(commit->parents);
1799                 cnt = commit_list_count(h);
1800                 free_commit_list(commit->parents);
1801                 commit->parents = h;
1802         }
1803
1804         /*
1805          * A commit simplifies to itself if it is a root, if it is
1806          * UNINTERESTING, if it touches the given paths, or if it is a
1807          * merge and its parents simplifies to more than one commits
1808          * (the first two cases are already handled at the beginning of
1809          * this function).
1810          *
1811          * Otherwise, it simplifies to what its sole parent simplifies to.
1812          */
1813         if (!cnt ||
1814             (commit->object.flags & UNINTERESTING) ||
1815             !(commit->object.flags & TREESAME) ||
1816             (1 < cnt))
1817                 st->simplified = commit;
1818         else {
1819                 pst = locate_simplify_state(revs, commit->parents->item);
1820                 st->simplified = pst->simplified;
1821         }
1822         return tail;
1823 }
1824
1825 static void simplify_merges(struct rev_info *revs)
1826 {
1827         struct commit_list *list;
1828         struct commit_list *yet_to_do, **tail;
1829
1830         if (!revs->topo_order)
1831                 sort_in_topological_order(&revs->commits, revs->lifo);
1832         if (!revs->prune)
1833                 return;
1834
1835         /* feed the list reversed */
1836         yet_to_do = NULL;
1837         for (list = revs->commits; list; list = list->next)
1838                 commit_list_insert(list->item, &yet_to_do);
1839         while (yet_to_do) {
1840                 list = yet_to_do;
1841                 yet_to_do = NULL;
1842                 tail = &yet_to_do;
1843                 while (list) {
1844                         struct commit *commit = list->item;
1845                         struct commit_list *next = list->next;
1846                         free(list);
1847                         list = next;
1848                         tail = simplify_one(revs, commit, tail);
1849                 }
1850         }
1851
1852         /* clean up the result, removing the simplified ones */
1853         list = revs->commits;
1854         revs->commits = NULL;
1855         tail = &revs->commits;
1856         while (list) {
1857                 struct commit *commit = list->item;
1858                 struct commit_list *next = list->next;
1859                 struct merge_simplify_state *st;
1860                 free(list);
1861                 list = next;
1862                 st = locate_simplify_state(revs, commit);
1863                 if (st->simplified == commit)
1864                         tail = &commit_list_insert(commit, tail)->next;
1865         }
1866 }
1867
1868 static void set_children(struct rev_info *revs)
1869 {
1870         struct commit_list *l;
1871         for (l = revs->commits; l; l = l->next) {
1872                 struct commit *commit = l->item;
1873                 struct commit_list *p;
1874
1875                 for (p = commit->parents; p; p = p->next)
1876                         add_child(revs, p->item, commit);
1877         }
1878 }
1879
1880 int prepare_revision_walk(struct rev_info *revs)
1881 {
1882         int nr = revs->pending.nr;
1883         struct object_array_entry *e, *list;
1884
1885         e = list = revs->pending.objects;
1886         revs->pending.nr = 0;
1887         revs->pending.alloc = 0;
1888         revs->pending.objects = NULL;
1889         while (--nr >= 0) {
1890                 struct commit *commit = handle_commit(revs, e->item, e->name);
1891                 if (commit) {
1892                         if (!(commit->object.flags & SEEN)) {
1893                                 commit->object.flags |= SEEN;
1894                                 commit_list_insert_by_date(commit, &revs->commits);
1895                         }
1896                 }
1897                 e++;
1898         }
1899         free(list);
1900
1901         if (revs->no_walk)
1902                 return 0;
1903         if (revs->limited)
1904                 if (limit_list(revs) < 0)
1905                         return -1;
1906         if (revs->topo_order)
1907                 sort_in_topological_order(&revs->commits, revs->lifo);
1908         if (revs->simplify_merges)
1909                 simplify_merges(revs);
1910         if (revs->children.name)
1911                 set_children(revs);
1912         return 0;
1913 }
1914
1915 enum rewrite_result {
1916         rewrite_one_ok,
1917         rewrite_one_noparents,
1918         rewrite_one_error
1919 };
1920
1921 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1922 {
1923         struct commit_list *cache = NULL;
1924
1925         for (;;) {
1926                 struct commit *p = *pp;
1927                 if (!revs->limited)
1928                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1929                                 return rewrite_one_error;
1930                 if (p->parents && p->parents->next)
1931                         return rewrite_one_ok;
1932                 if (p->object.flags & UNINTERESTING)
1933                         return rewrite_one_ok;
1934                 if (!(p->object.flags & TREESAME))
1935                         return rewrite_one_ok;
1936                 if (!p->parents)
1937                         return rewrite_one_noparents;
1938                 *pp = p->parents->item;
1939         }
1940 }
1941
1942 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1943 {
1944         struct commit_list **pp = &commit->parents;
1945         while (*pp) {
1946                 struct commit_list *parent = *pp;
1947                 switch (rewrite_one(revs, &parent->item)) {
1948                 case rewrite_one_ok:
1949                         break;
1950                 case rewrite_one_noparents:
1951                         *pp = parent->next;
1952                         continue;
1953                 case rewrite_one_error:
1954                         return -1;
1955                 }
1956                 pp = &parent->next;
1957         }
1958         remove_duplicate_parents(commit);
1959         return 0;
1960 }
1961
1962 static int commit_match(struct commit *commit, struct rev_info *opt)
1963 {
1964         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
1965                 return 1;
1966         return grep_buffer(&opt->grep_filter,
1967                            NULL, /* we say nothing, not even filename */
1968                            commit->buffer, strlen(commit->buffer));
1969 }
1970
1971 static inline int want_ancestry(struct rev_info *revs)
1972 {
1973         return (revs->rewrite_parents || revs->children.name);
1974 }
1975
1976 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
1977 {
1978         if (commit->object.flags & SHOWN)
1979                 return commit_ignore;
1980         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
1981                 return commit_ignore;
1982         if (revs->show_all)
1983                 return commit_show;
1984         if (commit->object.flags & UNINTERESTING)
1985                 return commit_ignore;
1986         if (revs->min_age != -1 && (commit->date > revs->min_age))
1987                 return commit_ignore;
1988         if (revs->no_merges && commit->parents && commit->parents->next)
1989                 return commit_ignore;
1990         if (revs->merges_only && !(commit->parents && commit->parents->next))
1991                 return commit_ignore;
1992         if (!commit_match(commit, revs))
1993                 return commit_ignore;
1994         if (revs->prune && revs->dense) {
1995                 /* Commit without changes? */
1996                 if (commit->object.flags & TREESAME) {
1997                         /* drop merges unless we want parenthood */
1998                         if (!want_ancestry(revs))
1999                                 return commit_ignore;
2000                         /* non-merge - always ignore it */
2001                         if (!commit->parents || !commit->parents->next)
2002                                 return commit_ignore;
2003                 }
2004         }
2005         return commit_show;
2006 }
2007
2008 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
2009 {
2010         enum commit_action action = get_commit_action(revs, commit);
2011
2012         if (action == commit_show &&
2013             !revs->show_all &&
2014             revs->prune && revs->dense && want_ancestry(revs)) {
2015                 if (rewrite_parents(revs, commit) < 0)
2016                         return commit_error;
2017         }
2018         return action;
2019 }
2020
2021 static struct commit *get_revision_1(struct rev_info *revs)
2022 {
2023         if (!revs->commits)
2024                 return NULL;
2025
2026         do {
2027                 struct commit_list *entry = revs->commits;
2028                 struct commit *commit = entry->item;
2029
2030                 revs->commits = entry->next;
2031                 free(entry);
2032
2033                 if (revs->reflog_info) {
2034                         fake_reflog_parent(revs->reflog_info, commit);
2035                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
2036                 }
2037
2038                 /*
2039                  * If we haven't done the list limiting, we need to look at
2040                  * the parents here. We also need to do the date-based limiting
2041                  * that we'd otherwise have done in limit_list().
2042                  */
2043                 if (!revs->limited) {
2044                         if (revs->max_age != -1 &&
2045                             (commit->date < revs->max_age))
2046                                 continue;
2047                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
2048                                 die("Failed to traverse parents of commit %s",
2049                                     sha1_to_hex(commit->object.sha1));
2050                 }
2051
2052                 switch (simplify_commit(revs, commit)) {
2053                 case commit_ignore:
2054                         continue;
2055                 case commit_error:
2056                         die("Failed to simplify parents of commit %s",
2057                             sha1_to_hex(commit->object.sha1));
2058                 default:
2059                         return commit;
2060                 }
2061         } while (revs->commits);
2062         return NULL;
2063 }
2064
2065 static void gc_boundary(struct object_array *array)
2066 {
2067         unsigned nr = array->nr;
2068         unsigned alloc = array->alloc;
2069         struct object_array_entry *objects = array->objects;
2070
2071         if (alloc <= nr) {
2072                 unsigned i, j;
2073                 for (i = j = 0; i < nr; i++) {
2074                         if (objects[i].item->flags & SHOWN)
2075                                 continue;
2076                         if (i != j)
2077                                 objects[j] = objects[i];
2078                         j++;
2079                 }
2080                 for (i = j; i < nr; i++)
2081                         objects[i].item = NULL;
2082                 array->nr = j;
2083         }
2084 }
2085
2086 static void create_boundary_commit_list(struct rev_info *revs)
2087 {
2088         unsigned i;
2089         struct commit *c;
2090         struct object_array *array = &revs->boundary_commits;
2091         struct object_array_entry *objects = array->objects;
2092
2093         /*
2094          * If revs->commits is non-NULL at this point, an error occurred in
2095          * get_revision_1().  Ignore the error and continue printing the
2096          * boundary commits anyway.  (This is what the code has always
2097          * done.)
2098          */
2099         if (revs->commits) {
2100                 free_commit_list(revs->commits);
2101                 revs->commits = NULL;
2102         }
2103
2104         /*
2105          * Put all of the actual boundary commits from revs->boundary_commits
2106          * into revs->commits
2107          */
2108         for (i = 0; i < array->nr; i++) {
2109                 c = (struct commit *)(objects[i].item);
2110                 if (!c)
2111                         continue;
2112                 if (!(c->object.flags & CHILD_SHOWN))
2113                         continue;
2114                 if (c->object.flags & (SHOWN | BOUNDARY))
2115                         continue;
2116                 c->object.flags |= BOUNDARY;
2117                 commit_list_insert(c, &revs->commits);
2118         }
2119
2120         /*
2121          * If revs->topo_order is set, sort the boundary commits
2122          * in topological order
2123          */
2124         sort_in_topological_order(&revs->commits, revs->lifo);
2125 }
2126
2127 static struct commit *get_revision_internal(struct rev_info *revs)
2128 {
2129         struct commit *c = NULL;
2130         struct commit_list *l;
2131
2132         if (revs->boundary == 2) {
2133                 /*
2134                  * All of the normal commits have already been returned,
2135                  * and we are now returning boundary commits.
2136                  * create_boundary_commit_list() has populated
2137                  * revs->commits with the remaining commits to return.
2138                  */
2139                 c = pop_commit(&revs->commits);
2140                 if (c)
2141                         c->object.flags |= SHOWN;
2142                 return c;
2143         }
2144
2145         /*
2146          * Now pick up what they want to give us
2147          */
2148         c = get_revision_1(revs);
2149         if (c) {
2150                 while (0 < revs->skip_count) {
2151                         revs->skip_count--;
2152                         c = get_revision_1(revs);
2153                         if (!c)
2154                                 break;
2155                 }
2156         }
2157
2158         /*
2159          * Check the max_count.
2160          */
2161         switch (revs->max_count) {
2162         case -1:
2163                 break;
2164         case 0:
2165                 c = NULL;
2166                 break;
2167         default:
2168                 revs->max_count--;
2169         }
2170
2171         if (c)
2172                 c->object.flags |= SHOWN;
2173
2174         if (!revs->boundary) {
2175                 return c;
2176         }
2177
2178         if (!c) {
2179                 /*
2180                  * get_revision_1() runs out the commits, and
2181                  * we are done computing the boundaries.
2182                  * switch to boundary commits output mode.
2183                  */
2184                 revs->boundary = 2;
2185
2186                 /*
2187                  * Update revs->commits to contain the list of
2188                  * boundary commits.
2189                  */
2190                 create_boundary_commit_list(revs);
2191
2192                 return get_revision_internal(revs);
2193         }
2194
2195         /*
2196          * boundary commits are the commits that are parents of the
2197          * ones we got from get_revision_1() but they themselves are
2198          * not returned from get_revision_1().  Before returning
2199          * 'c', we need to mark its parents that they could be boundaries.
2200          */
2201
2202         for (l = c->parents; l; l = l->next) {
2203                 struct object *p;
2204                 p = &(l->item->object);
2205                 if (p->flags & (CHILD_SHOWN | SHOWN))
2206                         continue;
2207                 p->flags |= CHILD_SHOWN;
2208                 gc_boundary(&revs->boundary_commits);
2209                 add_object_array(p, NULL, &revs->boundary_commits);
2210         }
2211
2212         return c;
2213 }
2214
2215 struct commit *get_revision(struct rev_info *revs)
2216 {
2217         struct commit *c;
2218         struct commit_list *reversed;
2219
2220         if (revs->reverse) {
2221                 reversed = NULL;
2222                 while ((c = get_revision_internal(revs))) {
2223                         commit_list_insert(c, &reversed);
2224                 }
2225                 revs->commits = reversed;
2226                 revs->reverse = 0;
2227                 revs->reverse_output_stage = 1;
2228         }
2229
2230         if (revs->reverse_output_stage)
2231                 return pop_commit(&revs->commits);
2232
2233         c = get_revision_internal(revs);
2234         if (c && revs->graph)
2235                 graph_update(revs->graph, c);
2236         return c;
2237 }