Merge branch 'rs/empty-archive'
[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 #include "mailmap.h"
17
18 volatile show_early_output_fn_t show_early_output;
19
20 char *path_name(const struct name_path *path, const char *name)
21 {
22         const struct name_path *p;
23         char *n, *m;
24         int nlen = strlen(name);
25         int len = nlen + 1;
26
27         for (p = path; p; p = p->up) {
28                 if (p->elem_len)
29                         len += p->elem_len + 1;
30         }
31         n = xmalloc(len);
32         m = n + len - (nlen + 1);
33         strcpy(m, name);
34         for (p = path; p; p = p->up) {
35                 if (p->elem_len) {
36                         m -= p->elem_len + 1;
37                         memcpy(m, p->elem, p->elem_len);
38                         m[p->elem_len] = '/';
39                 }
40         }
41         return n;
42 }
43
44 static int show_path_component_truncated(FILE *out, const char *name, int len)
45 {
46         int cnt;
47         for (cnt = 0; cnt < len; cnt++) {
48                 int ch = name[cnt];
49                 if (!ch || ch == '\n')
50                         return -1;
51                 fputc(ch, out);
52         }
53         return len;
54 }
55
56 static int show_path_truncated(FILE *out, const struct name_path *path)
57 {
58         int emitted, ours;
59
60         if (!path)
61                 return 0;
62         emitted = show_path_truncated(out, path->up);
63         if (emitted < 0)
64                 return emitted;
65         if (emitted)
66                 fputc('/', out);
67         ours = show_path_component_truncated(out, path->elem, path->elem_len);
68         if (ours < 0)
69                 return ours;
70         return ours || emitted;
71 }
72
73 void show_object_with_name(FILE *out, struct object *obj, const struct name_path *path, const char *component)
74 {
75         struct name_path leaf;
76         leaf.up = (struct name_path *)path;
77         leaf.elem = component;
78         leaf.elem_len = strlen(component);
79
80         fprintf(out, "%s ", sha1_to_hex(obj->sha1));
81         show_path_truncated(out, &leaf);
82         fputc('\n', out);
83 }
84
85 void add_object(struct object *obj,
86                 struct object_array *p,
87                 struct name_path *path,
88                 const char *name)
89 {
90         add_object_array(obj, path_name(path, name), p);
91 }
92
93 static void mark_blob_uninteresting(struct blob *blob)
94 {
95         if (!blob)
96                 return;
97         if (blob->object.flags & UNINTERESTING)
98                 return;
99         blob->object.flags |= UNINTERESTING;
100 }
101
102 void mark_tree_uninteresting(struct tree *tree)
103 {
104         struct tree_desc desc;
105         struct name_entry entry;
106         struct object *obj = &tree->object;
107
108         if (!tree)
109                 return;
110         if (obj->flags & UNINTERESTING)
111                 return;
112         obj->flags |= UNINTERESTING;
113         if (!has_sha1_file(obj->sha1))
114                 return;
115         if (parse_tree(tree) < 0)
116                 die("bad tree %s", sha1_to_hex(obj->sha1));
117
118         init_tree_desc(&desc, tree->buffer, tree->size);
119         while (tree_entry(&desc, &entry)) {
120                 switch (object_type(entry.mode)) {
121                 case OBJ_TREE:
122                         mark_tree_uninteresting(lookup_tree(entry.sha1));
123                         break;
124                 case OBJ_BLOB:
125                         mark_blob_uninteresting(lookup_blob(entry.sha1));
126                         break;
127                 default:
128                         /* Subproject commit - not in this repository */
129                         break;
130                 }
131         }
132
133         /*
134          * We don't care about the tree any more
135          * after it has been marked uninteresting.
136          */
137         free(tree->buffer);
138         tree->buffer = NULL;
139 }
140
141 void mark_parents_uninteresting(struct commit *commit)
142 {
143         struct commit_list *parents = NULL, *l;
144
145         for (l = commit->parents; l; l = l->next)
146                 commit_list_insert(l->item, &parents);
147
148         while (parents) {
149                 struct commit *commit = parents->item;
150                 l = parents;
151                 parents = parents->next;
152                 free(l);
153
154                 while (commit) {
155                         /*
156                          * A missing commit is ok iff its parent is marked
157                          * uninteresting.
158                          *
159                          * We just mark such a thing parsed, so that when
160                          * it is popped next time around, we won't be trying
161                          * to parse it and get an error.
162                          */
163                         if (!has_sha1_file(commit->object.sha1))
164                                 commit->object.parsed = 1;
165
166                         if (commit->object.flags & UNINTERESTING)
167                                 break;
168
169                         commit->object.flags |= UNINTERESTING;
170
171                         /*
172                          * Normally we haven't parsed the parent
173                          * yet, so we won't have a parent of a parent
174                          * here. However, it may turn out that we've
175                          * reached this commit some other way (where it
176                          * wasn't uninteresting), in which case we need
177                          * to mark its parents recursively too..
178                          */
179                         if (!commit->parents)
180                                 break;
181
182                         for (l = commit->parents->next; l; l = l->next)
183                                 commit_list_insert(l->item, &parents);
184                         commit = commit->parents->item;
185                 }
186         }
187 }
188
189 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
190 {
191         if (!obj)
192                 return;
193         if (revs->no_walk && (obj->flags & UNINTERESTING))
194                 revs->no_walk = 0;
195         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
196                 struct strbuf buf = STRBUF_INIT;
197                 int len = interpret_branch_name(name, &buf);
198                 int st;
199
200                 if (0 < len && name[len] && buf.len)
201                         strbuf_addstr(&buf, name + len);
202                 st = add_reflog_for_walk(revs->reflog_info,
203                                          (struct commit *)obj,
204                                          buf.buf[0] ? buf.buf: name);
205                 strbuf_release(&buf);
206                 if (st)
207                         return;
208         }
209         add_object_array_with_mode(obj, name, &revs->pending, mode);
210 }
211
212 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
213 {
214         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
215 }
216
217 void add_head_to_pending(struct rev_info *revs)
218 {
219         unsigned char sha1[20];
220         struct object *obj;
221         if (get_sha1("HEAD", sha1))
222                 return;
223         obj = parse_object(sha1);
224         if (!obj)
225                 return;
226         add_pending_object(revs, obj, "HEAD");
227 }
228
229 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
230 {
231         struct object *object;
232
233         object = parse_object(sha1);
234         if (!object) {
235                 if (revs->ignore_missing)
236                         return object;
237                 die("bad object %s", name);
238         }
239         object->flags |= flags;
240         return object;
241 }
242
243 void add_pending_sha1(struct rev_info *revs, const char *name,
244                       const unsigned char *sha1, unsigned int flags)
245 {
246         struct object *object = get_reference(revs, name, sha1, flags);
247         add_pending_object(revs, object, name);
248 }
249
250 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
251 {
252         unsigned long flags = object->flags;
253
254         /*
255          * Tag object? Look what it points to..
256          */
257         while (object->type == OBJ_TAG) {
258                 struct tag *tag = (struct tag *) object;
259                 if (revs->tag_objects && !(flags & UNINTERESTING))
260                         add_pending_object(revs, object, tag->tag);
261                 if (!tag->tagged)
262                         die("bad tag");
263                 object = parse_object(tag->tagged->sha1);
264                 if (!object) {
265                         if (flags & UNINTERESTING)
266                                 return NULL;
267                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
268                 }
269         }
270
271         /*
272          * Commit object? Just return it, we'll do all the complex
273          * reachability crud.
274          */
275         if (object->type == OBJ_COMMIT) {
276                 struct commit *commit = (struct commit *)object;
277                 if (parse_commit(commit) < 0)
278                         die("unable to parse commit %s", name);
279                 if (flags & UNINTERESTING) {
280                         commit->object.flags |= UNINTERESTING;
281                         mark_parents_uninteresting(commit);
282                         revs->limited = 1;
283                 }
284                 if (revs->show_source && !commit->util)
285                         commit->util = (void *) name;
286                 return commit;
287         }
288
289         /*
290          * Tree object? Either mark it uninteresting, or add it
291          * to the list of objects to look at later..
292          */
293         if (object->type == OBJ_TREE) {
294                 struct tree *tree = (struct tree *)object;
295                 if (!revs->tree_objects)
296                         return NULL;
297                 if (flags & UNINTERESTING) {
298                         mark_tree_uninteresting(tree);
299                         return NULL;
300                 }
301                 add_pending_object(revs, object, "");
302                 return NULL;
303         }
304
305         /*
306          * Blob object? You know the drill by now..
307          */
308         if (object->type == OBJ_BLOB) {
309                 struct blob *blob = (struct blob *)object;
310                 if (!revs->blob_objects)
311                         return NULL;
312                 if (flags & UNINTERESTING) {
313                         mark_blob_uninteresting(blob);
314                         return NULL;
315                 }
316                 add_pending_object(revs, object, "");
317                 return NULL;
318         }
319         die("%s is unknown object", name);
320 }
321
322 static int everybody_uninteresting(struct commit_list *orig)
323 {
324         struct commit_list *list = orig;
325         while (list) {
326                 struct commit *commit = list->item;
327                 list = list->next;
328                 if (commit->object.flags & UNINTERESTING)
329                         continue;
330                 return 0;
331         }
332         return 1;
333 }
334
335 /*
336  * The goal is to get REV_TREE_NEW as the result only if the
337  * diff consists of all '+' (and no other changes), REV_TREE_OLD
338  * if the whole diff is removal of old data, and otherwise
339  * REV_TREE_DIFFERENT (of course if the trees are the same we
340  * want REV_TREE_SAME).
341  * That means that once we get to REV_TREE_DIFFERENT, we do not
342  * have to look any further.
343  */
344 static int tree_difference = REV_TREE_SAME;
345
346 static void file_add_remove(struct diff_options *options,
347                     int addremove, unsigned mode,
348                     const unsigned char *sha1,
349                     int sha1_valid,
350                     const char *fullpath, unsigned dirty_submodule)
351 {
352         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
353
354         tree_difference |= diff;
355         if (tree_difference == REV_TREE_DIFFERENT)
356                 DIFF_OPT_SET(options, HAS_CHANGES);
357 }
358
359 static void file_change(struct diff_options *options,
360                  unsigned old_mode, unsigned new_mode,
361                  const unsigned char *old_sha1,
362                  const unsigned char *new_sha1,
363                  int old_sha1_valid, int new_sha1_valid,
364                  const char *fullpath,
365                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
366 {
367         tree_difference = REV_TREE_DIFFERENT;
368         DIFF_OPT_SET(options, HAS_CHANGES);
369 }
370
371 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
372 {
373         struct tree *t1 = parent->tree;
374         struct tree *t2 = commit->tree;
375
376         if (!t1)
377                 return REV_TREE_NEW;
378         if (!t2)
379                 return REV_TREE_OLD;
380
381         if (revs->simplify_by_decoration) {
382                 /*
383                  * If we are simplifying by decoration, then the commit
384                  * is worth showing if it has a tag pointing at it.
385                  */
386                 if (lookup_decoration(&name_decoration, &commit->object))
387                         return REV_TREE_DIFFERENT;
388                 /*
389                  * A commit that is not pointed by a tag is uninteresting
390                  * if we are not limited by path.  This means that you will
391                  * see the usual "commits that touch the paths" plus any
392                  * tagged commit by specifying both --simplify-by-decoration
393                  * and pathspec.
394                  */
395                 if (!revs->prune_data.nr)
396                         return REV_TREE_SAME;
397         }
398
399         tree_difference = REV_TREE_SAME;
400         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
401         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
402                            &revs->pruning) < 0)
403                 return REV_TREE_DIFFERENT;
404         return tree_difference;
405 }
406
407 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
408 {
409         int retval;
410         void *tree;
411         unsigned long size;
412         struct tree_desc empty, real;
413         struct tree *t1 = commit->tree;
414
415         if (!t1)
416                 return 0;
417
418         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
419         if (!tree)
420                 return 0;
421         init_tree_desc(&real, tree, size);
422         init_tree_desc(&empty, "", 0);
423
424         tree_difference = REV_TREE_SAME;
425         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
426         retval = diff_tree(&empty, &real, "", &revs->pruning);
427         free(tree);
428
429         return retval >= 0 && (tree_difference == REV_TREE_SAME);
430 }
431
432 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
433 {
434         struct commit_list **pp, *parent;
435         int tree_changed = 0, tree_same = 0, nth_parent = 0;
436
437         /*
438          * If we don't do pruning, everything is interesting
439          */
440         if (!revs->prune)
441                 return;
442
443         if (!commit->tree)
444                 return;
445
446         if (!commit->parents) {
447                 if (rev_same_tree_as_empty(revs, commit))
448                         commit->object.flags |= TREESAME;
449                 return;
450         }
451
452         /*
453          * Normal non-merge commit? If we don't want to make the
454          * history dense, we consider it always to be a change..
455          */
456         if (!revs->dense && !commit->parents->next)
457                 return;
458
459         pp = &commit->parents;
460         while ((parent = *pp) != NULL) {
461                 struct commit *p = parent->item;
462
463                 /*
464                  * Do not compare with later parents when we care only about
465                  * the first parent chain, in order to avoid derailing the
466                  * traversal to follow a side branch that brought everything
467                  * in the path we are limited to by the pathspec.
468                  */
469                 if (revs->first_parent_only && nth_parent++)
470                         break;
471                 if (parse_commit(p) < 0)
472                         die("cannot simplify commit %s (because of %s)",
473                             sha1_to_hex(commit->object.sha1),
474                             sha1_to_hex(p->object.sha1));
475                 switch (rev_compare_tree(revs, p, commit)) {
476                 case REV_TREE_SAME:
477                         tree_same = 1;
478                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
479                                 /* Even if a merge with an uninteresting
480                                  * side branch brought the entire change
481                                  * we are interested in, we do not want
482                                  * to lose the other branches of this
483                                  * merge, so we just keep going.
484                                  */
485                                 pp = &parent->next;
486                                 continue;
487                         }
488                         parent->next = NULL;
489                         commit->parents = parent;
490                         commit->object.flags |= TREESAME;
491                         return;
492
493                 case REV_TREE_NEW:
494                         if (revs->remove_empty_trees &&
495                             rev_same_tree_as_empty(revs, p)) {
496                                 /* We are adding all the specified
497                                  * paths from this parent, so the
498                                  * history beyond this parent is not
499                                  * interesting.  Remove its parents
500                                  * (they are grandparents for us).
501                                  * IOW, we pretend this parent is a
502                                  * "root" commit.
503                                  */
504                                 if (parse_commit(p) < 0)
505                                         die("cannot simplify commit %s (invalid %s)",
506                                             sha1_to_hex(commit->object.sha1),
507                                             sha1_to_hex(p->object.sha1));
508                                 p->parents = NULL;
509                         }
510                 /* fallthrough */
511                 case REV_TREE_OLD:
512                 case REV_TREE_DIFFERENT:
513                         tree_changed = 1;
514                         pp = &parent->next;
515                         continue;
516                 }
517                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
518         }
519         if (tree_changed && !tree_same)
520                 return;
521         commit->object.flags |= TREESAME;
522 }
523
524 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
525                     struct commit_list *cached_base, struct commit_list **cache)
526 {
527         struct commit_list *new_entry;
528
529         if (cached_base && p->date < cached_base->item->date)
530                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
531         else
532                 new_entry = commit_list_insert_by_date(p, head);
533
534         if (cache && (!*cache || p->date < (*cache)->item->date))
535                 *cache = new_entry;
536 }
537
538 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
539                     struct commit_list **list, struct commit_list **cache_ptr)
540 {
541         struct commit_list *parent = commit->parents;
542         unsigned left_flag;
543         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
544
545         if (commit->object.flags & ADDED)
546                 return 0;
547         commit->object.flags |= ADDED;
548
549         /*
550          * If the commit is uninteresting, don't try to
551          * prune parents - we want the maximal uninteresting
552          * set.
553          *
554          * Normally we haven't parsed the parent
555          * yet, so we won't have a parent of a parent
556          * here. However, it may turn out that we've
557          * reached this commit some other way (where it
558          * wasn't uninteresting), in which case we need
559          * to mark its parents recursively too..
560          */
561         if (commit->object.flags & UNINTERESTING) {
562                 while (parent) {
563                         struct commit *p = parent->item;
564                         parent = parent->next;
565                         if (p)
566                                 p->object.flags |= UNINTERESTING;
567                         if (parse_commit(p) < 0)
568                                 continue;
569                         if (p->parents)
570                                 mark_parents_uninteresting(p);
571                         if (p->object.flags & SEEN)
572                                 continue;
573                         p->object.flags |= SEEN;
574                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
575                 }
576                 return 0;
577         }
578
579         /*
580          * Ok, the commit wasn't uninteresting. Try to
581          * simplify the commit history and find the parent
582          * that has no differences in the path set if one exists.
583          */
584         try_to_simplify_commit(revs, commit);
585
586         if (revs->no_walk)
587                 return 0;
588
589         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
590
591         for (parent = commit->parents; parent; parent = parent->next) {
592                 struct commit *p = parent->item;
593
594                 if (parse_commit(p) < 0)
595                         return -1;
596                 if (revs->show_source && !p->util)
597                         p->util = commit->util;
598                 p->object.flags |= left_flag;
599                 if (!(p->object.flags & SEEN)) {
600                         p->object.flags |= SEEN;
601                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
602                 }
603                 if (revs->first_parent_only)
604                         break;
605         }
606         return 0;
607 }
608
609 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
610 {
611         struct commit_list *p;
612         int left_count = 0, right_count = 0;
613         int left_first;
614         struct patch_ids ids;
615         unsigned cherry_flag;
616
617         /* First count the commits on the left and on the right */
618         for (p = list; p; p = p->next) {
619                 struct commit *commit = p->item;
620                 unsigned flags = commit->object.flags;
621                 if (flags & BOUNDARY)
622                         ;
623                 else if (flags & SYMMETRIC_LEFT)
624                         left_count++;
625                 else
626                         right_count++;
627         }
628
629         if (!left_count || !right_count)
630                 return;
631
632         left_first = left_count < right_count;
633         init_patch_ids(&ids);
634         ids.diffopts.pathspec = revs->diffopt.pathspec;
635
636         /* Compute patch-ids for one side */
637         for (p = list; p; p = p->next) {
638                 struct commit *commit = p->item;
639                 unsigned flags = commit->object.flags;
640
641                 if (flags & BOUNDARY)
642                         continue;
643                 /*
644                  * If we have fewer left, left_first is set and we omit
645                  * commits on the right branch in this loop.  If we have
646                  * fewer right, we skip the left ones.
647                  */
648                 if (left_first != !!(flags & SYMMETRIC_LEFT))
649                         continue;
650                 commit->util = add_commit_patch_id(commit, &ids);
651         }
652
653         /* either cherry_mark or cherry_pick are true */
654         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
655
656         /* Check the other side */
657         for (p = list; p; p = p->next) {
658                 struct commit *commit = p->item;
659                 struct patch_id *id;
660                 unsigned flags = commit->object.flags;
661
662                 if (flags & BOUNDARY)
663                         continue;
664                 /*
665                  * If we have fewer left, left_first is set and we omit
666                  * commits on the left branch in this loop.
667                  */
668                 if (left_first == !!(flags & SYMMETRIC_LEFT))
669                         continue;
670
671                 /*
672                  * Have we seen the same patch id?
673                  */
674                 id = has_commit_patch_id(commit, &ids);
675                 if (!id)
676                         continue;
677                 id->seen = 1;
678                 commit->object.flags |= cherry_flag;
679         }
680
681         /* Now check the original side for seen ones */
682         for (p = list; p; p = p->next) {
683                 struct commit *commit = p->item;
684                 struct patch_id *ent;
685
686                 ent = commit->util;
687                 if (!ent)
688                         continue;
689                 if (ent->seen)
690                         commit->object.flags |= cherry_flag;
691                 commit->util = NULL;
692         }
693
694         free_patch_ids(&ids);
695 }
696
697 /* How many extra uninteresting commits we want to see.. */
698 #define SLOP 5
699
700 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
701 {
702         /*
703          * No source list at all? We're definitely done..
704          */
705         if (!src)
706                 return 0;
707
708         /*
709          * Does the destination list contain entries with a date
710          * before the source list? Definitely _not_ done.
711          */
712         if (date <= src->item->date)
713                 return SLOP;
714
715         /*
716          * Does the source list still have interesting commits in
717          * it? Definitely not done..
718          */
719         if (!everybody_uninteresting(src))
720                 return SLOP;
721
722         /* Ok, we're closing in.. */
723         return slop-1;
724 }
725
726 /*
727  * "rev-list --ancestry-path A..B" computes commits that are ancestors
728  * of B but not ancestors of A but further limits the result to those
729  * that are descendants of A.  This takes the list of bottom commits and
730  * the result of "A..B" without --ancestry-path, and limits the latter
731  * further to the ones that can reach one of the commits in "bottom".
732  */
733 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
734 {
735         struct commit_list *p;
736         struct commit_list *rlist = NULL;
737         int made_progress;
738
739         /*
740          * Reverse the list so that it will be likely that we would
741          * process parents before children.
742          */
743         for (p = list; p; p = p->next)
744                 commit_list_insert(p->item, &rlist);
745
746         for (p = bottom; p; p = p->next)
747                 p->item->object.flags |= TMP_MARK;
748
749         /*
750          * Mark the ones that can reach bottom commits in "list",
751          * in a bottom-up fashion.
752          */
753         do {
754                 made_progress = 0;
755                 for (p = rlist; p; p = p->next) {
756                         struct commit *c = p->item;
757                         struct commit_list *parents;
758                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
759                                 continue;
760                         for (parents = c->parents;
761                              parents;
762                              parents = parents->next) {
763                                 if (!(parents->item->object.flags & TMP_MARK))
764                                         continue;
765                                 c->object.flags |= TMP_MARK;
766                                 made_progress = 1;
767                                 break;
768                         }
769                 }
770         } while (made_progress);
771
772         /*
773          * NEEDSWORK: decide if we want to remove parents that are
774          * not marked with TMP_MARK from commit->parents for commits
775          * in the resulting list.  We may not want to do that, though.
776          */
777
778         /*
779          * The ones that are not marked with TMP_MARK are uninteresting
780          */
781         for (p = list; p; p = p->next) {
782                 struct commit *c = p->item;
783                 if (c->object.flags & TMP_MARK)
784                         continue;
785                 c->object.flags |= UNINTERESTING;
786         }
787
788         /* We are done with the TMP_MARK */
789         for (p = list; p; p = p->next)
790                 p->item->object.flags &= ~TMP_MARK;
791         for (p = bottom; p; p = p->next)
792                 p->item->object.flags &= ~TMP_MARK;
793         free_commit_list(rlist);
794 }
795
796 /*
797  * Before walking the history, keep the set of "negative" refs the
798  * caller has asked to exclude.
799  *
800  * This is used to compute "rev-list --ancestry-path A..B", as we need
801  * to filter the result of "A..B" further to the ones that can actually
802  * reach A.
803  */
804 static struct commit_list *collect_bottom_commits(struct rev_info *revs)
805 {
806         struct commit_list *bottom = NULL;
807         int i;
808         for (i = 0; i < revs->cmdline.nr; i++) {
809                 struct rev_cmdline_entry *elem = &revs->cmdline.rev[i];
810                 if ((elem->flags & UNINTERESTING) &&
811                     elem->item->type == OBJ_COMMIT)
812                         commit_list_insert((struct commit *)elem->item, &bottom);
813         }
814         return bottom;
815 }
816
817 /* Assumes either left_only or right_only is set */
818 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
819 {
820         struct commit_list *p;
821
822         for (p = list; p; p = p->next) {
823                 struct commit *commit = p->item;
824
825                 if (revs->right_only) {
826                         if (commit->object.flags & SYMMETRIC_LEFT)
827                                 commit->object.flags |= SHOWN;
828                 } else  /* revs->left_only is set */
829                         if (!(commit->object.flags & SYMMETRIC_LEFT))
830                                 commit->object.flags |= SHOWN;
831         }
832 }
833
834 static int limit_list(struct rev_info *revs)
835 {
836         int slop = SLOP;
837         unsigned long date = ~0ul;
838         struct commit_list *list = revs->commits;
839         struct commit_list *newlist = NULL;
840         struct commit_list **p = &newlist;
841         struct commit_list *bottom = NULL;
842
843         if (revs->ancestry_path) {
844                 bottom = collect_bottom_commits(revs);
845                 if (!bottom)
846                         die("--ancestry-path given but there are no bottom commits");
847         }
848
849         while (list) {
850                 struct commit_list *entry = list;
851                 struct commit *commit = list->item;
852                 struct object *obj = &commit->object;
853                 show_early_output_fn_t show;
854
855                 list = list->next;
856                 free(entry);
857
858                 if (revs->max_age != -1 && (commit->date < revs->max_age))
859                         obj->flags |= UNINTERESTING;
860                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
861                         return -1;
862                 if (obj->flags & UNINTERESTING) {
863                         mark_parents_uninteresting(commit);
864                         if (revs->show_all)
865                                 p = &commit_list_insert(commit, p)->next;
866                         slop = still_interesting(list, date, slop);
867                         if (slop)
868                                 continue;
869                         /* If showing all, add the whole pending list to the end */
870                         if (revs->show_all)
871                                 *p = list;
872                         break;
873                 }
874                 if (revs->min_age != -1 && (commit->date > revs->min_age))
875                         continue;
876                 date = commit->date;
877                 p = &commit_list_insert(commit, p)->next;
878
879                 show = show_early_output;
880                 if (!show)
881                         continue;
882
883                 show(revs, newlist);
884                 show_early_output = NULL;
885         }
886         if (revs->cherry_pick || revs->cherry_mark)
887                 cherry_pick_list(newlist, revs);
888
889         if (revs->left_only || revs->right_only)
890                 limit_left_right(newlist, revs);
891
892         if (bottom) {
893                 limit_to_ancestry(bottom, newlist);
894                 free_commit_list(bottom);
895         }
896
897         revs->commits = newlist;
898         return 0;
899 }
900
901 static void add_rev_cmdline(struct rev_info *revs,
902                             struct object *item,
903                             const char *name,
904                             int whence,
905                             unsigned flags)
906 {
907         struct rev_cmdline_info *info = &revs->cmdline;
908         int nr = info->nr;
909
910         ALLOC_GROW(info->rev, nr + 1, info->alloc);
911         info->rev[nr].item = item;
912         info->rev[nr].name = name;
913         info->rev[nr].whence = whence;
914         info->rev[nr].flags = flags;
915         info->nr++;
916 }
917
918 struct all_refs_cb {
919         int all_flags;
920         int warned_bad_reflog;
921         struct rev_info *all_revs;
922         const char *name_for_errormsg;
923 };
924
925 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
926 {
927         struct all_refs_cb *cb = cb_data;
928         struct object *object = get_reference(cb->all_revs, path, sha1,
929                                               cb->all_flags);
930         add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
931         add_pending_sha1(cb->all_revs, path, sha1, cb->all_flags);
932         return 0;
933 }
934
935 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
936         unsigned flags)
937 {
938         cb->all_revs = revs;
939         cb->all_flags = flags;
940 }
941
942 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
943                 int (*for_each)(const char *, each_ref_fn, void *))
944 {
945         struct all_refs_cb cb;
946         init_all_refs_cb(&cb, revs, flags);
947         for_each(submodule, handle_one_ref, &cb);
948 }
949
950 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
951 {
952         struct all_refs_cb *cb = cb_data;
953         if (!is_null_sha1(sha1)) {
954                 struct object *o = parse_object(sha1);
955                 if (o) {
956                         o->flags |= cb->all_flags;
957                         /* ??? CMDLINEFLAGS ??? */
958                         add_pending_object(cb->all_revs, o, "");
959                 }
960                 else if (!cb->warned_bad_reflog) {
961                         warning("reflog of '%s' references pruned commits",
962                                 cb->name_for_errormsg);
963                         cb->warned_bad_reflog = 1;
964                 }
965         }
966 }
967
968 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
969                 const char *email, unsigned long timestamp, int tz,
970                 const char *message, void *cb_data)
971 {
972         handle_one_reflog_commit(osha1, cb_data);
973         handle_one_reflog_commit(nsha1, cb_data);
974         return 0;
975 }
976
977 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
978 {
979         struct all_refs_cb *cb = cb_data;
980         cb->warned_bad_reflog = 0;
981         cb->name_for_errormsg = path;
982         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
983         return 0;
984 }
985
986 static void handle_reflog(struct rev_info *revs, unsigned flags)
987 {
988         struct all_refs_cb cb;
989         cb.all_revs = revs;
990         cb.all_flags = flags;
991         for_each_reflog(handle_one_reflog, &cb);
992 }
993
994 static int add_parents_only(struct rev_info *revs, const char *arg_, int flags)
995 {
996         unsigned char sha1[20];
997         struct object *it;
998         struct commit *commit;
999         struct commit_list *parents;
1000         const char *arg = arg_;
1001
1002         if (*arg == '^') {
1003                 flags ^= UNINTERESTING;
1004                 arg++;
1005         }
1006         if (get_sha1_committish(arg, sha1))
1007                 return 0;
1008         while (1) {
1009                 it = get_reference(revs, arg, sha1, 0);
1010                 if (!it && revs->ignore_missing)
1011                         return 0;
1012                 if (it->type != OBJ_TAG)
1013                         break;
1014                 if (!((struct tag*)it)->tagged)
1015                         return 0;
1016                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
1017         }
1018         if (it->type != OBJ_COMMIT)
1019                 return 0;
1020         commit = (struct commit *)it;
1021         for (parents = commit->parents; parents; parents = parents->next) {
1022                 it = &parents->item->object;
1023                 it->flags |= flags;
1024                 add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
1025                 add_pending_object(revs, it, arg);
1026         }
1027         return 1;
1028 }
1029
1030 void init_revisions(struct rev_info *revs, const char *prefix)
1031 {
1032         memset(revs, 0, sizeof(*revs));
1033
1034         revs->abbrev = DEFAULT_ABBREV;
1035         revs->ignore_merges = 1;
1036         revs->simplify_history = 1;
1037         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
1038         DIFF_OPT_SET(&revs->pruning, QUICK);
1039         revs->pruning.add_remove = file_add_remove;
1040         revs->pruning.change = file_change;
1041         revs->lifo = 1;
1042         revs->dense = 1;
1043         revs->prefix = prefix;
1044         revs->max_age = -1;
1045         revs->min_age = -1;
1046         revs->skip_count = -1;
1047         revs->max_count = -1;
1048         revs->max_parents = -1;
1049
1050         revs->commit_format = CMIT_FMT_DEFAULT;
1051
1052         init_grep_defaults();
1053         grep_init(&revs->grep_filter, prefix);
1054         revs->grep_filter.status_only = 1;
1055         revs->grep_filter.regflags = REG_NEWLINE;
1056
1057         diff_setup(&revs->diffopt);
1058         if (prefix && !revs->diffopt.prefix) {
1059                 revs->diffopt.prefix = prefix;
1060                 revs->diffopt.prefix_length = strlen(prefix);
1061         }
1062
1063         revs->notes_opt.use_default_notes = -1;
1064 }
1065
1066 static void add_pending_commit_list(struct rev_info *revs,
1067                                     struct commit_list *commit_list,
1068                                     unsigned int flags)
1069 {
1070         while (commit_list) {
1071                 struct object *object = &commit_list->item->object;
1072                 object->flags |= flags;
1073                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
1074                 commit_list = commit_list->next;
1075         }
1076 }
1077
1078 static void prepare_show_merge(struct rev_info *revs)
1079 {
1080         struct commit_list *bases;
1081         struct commit *head, *other;
1082         unsigned char sha1[20];
1083         const char **prune = NULL;
1084         int i, prune_num = 1; /* counting terminating NULL */
1085
1086         if (get_sha1("HEAD", sha1))
1087                 die("--merge without HEAD?");
1088         head = lookup_commit_or_die(sha1, "HEAD");
1089         if (get_sha1("MERGE_HEAD", sha1))
1090                 die("--merge without MERGE_HEAD?");
1091         other = lookup_commit_or_die(sha1, "MERGE_HEAD");
1092         add_pending_object(revs, &head->object, "HEAD");
1093         add_pending_object(revs, &other->object, "MERGE_HEAD");
1094         bases = get_merge_bases(head, other, 1);
1095         add_pending_commit_list(revs, bases, UNINTERESTING);
1096         free_commit_list(bases);
1097         head->object.flags |= SYMMETRIC_LEFT;
1098
1099         if (!active_nr)
1100                 read_cache();
1101         for (i = 0; i < active_nr; i++) {
1102                 struct cache_entry *ce = active_cache[i];
1103                 if (!ce_stage(ce))
1104                         continue;
1105                 if (ce_path_match(ce, &revs->prune_data)) {
1106                         prune_num++;
1107                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
1108                         prune[prune_num-2] = ce->name;
1109                         prune[prune_num-1] = NULL;
1110                 }
1111                 while ((i+1 < active_nr) &&
1112                        ce_same_name(ce, active_cache[i+1]))
1113                         i++;
1114         }
1115         free_pathspec(&revs->prune_data);
1116         init_pathspec(&revs->prune_data, prune);
1117         revs->limited = 1;
1118 }
1119
1120 int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
1121 {
1122         struct object_context oc;
1123         char *dotdot;
1124         struct object *object;
1125         unsigned char sha1[20];
1126         int local_flags;
1127         const char *arg = arg_;
1128         int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
1129         unsigned get_sha1_flags = 0;
1130
1131         dotdot = strstr(arg, "..");
1132         if (dotdot) {
1133                 unsigned char from_sha1[20];
1134                 const char *next = dotdot + 2;
1135                 const char *this = arg;
1136                 int symmetric = *next == '.';
1137                 unsigned int flags_exclude = flags ^ UNINTERESTING;
1138                 static const char head_by_default[] = "HEAD";
1139                 unsigned int a_flags;
1140
1141                 *dotdot = 0;
1142                 next += symmetric;
1143
1144                 if (!*next)
1145                         next = head_by_default;
1146                 if (dotdot == arg)
1147                         this = head_by_default;
1148                 if (this == head_by_default && next == head_by_default &&
1149                     !symmetric) {
1150                         /*
1151                          * Just ".."?  That is not a range but the
1152                          * pathspec for the parent directory.
1153                          */
1154                         if (!cant_be_filename) {
1155                                 *dotdot = '.';
1156                                 return -1;
1157                         }
1158                 }
1159                 if (!get_sha1_committish(this, from_sha1) &&
1160                     !get_sha1_committish(next, sha1)) {
1161                         struct commit *a, *b;
1162                         struct commit_list *exclude;
1163
1164                         a = lookup_commit_reference(from_sha1);
1165                         b = lookup_commit_reference(sha1);
1166                         if (!a || !b) {
1167                                 if (revs->ignore_missing)
1168                                         return 0;
1169                                 die(symmetric ?
1170                                     "Invalid symmetric difference expression %s...%s" :
1171                                     "Invalid revision range %s..%s",
1172                                     arg, next);
1173                         }
1174
1175                         if (!cant_be_filename) {
1176                                 *dotdot = '.';
1177                                 verify_non_filename(revs->prefix, arg);
1178                         }
1179
1180                         if (symmetric) {
1181                                 exclude = get_merge_bases(a, b, 1);
1182                                 add_pending_commit_list(revs, exclude,
1183                                                         flags_exclude);
1184                                 free_commit_list(exclude);
1185                                 a_flags = flags | SYMMETRIC_LEFT;
1186                         } else
1187                                 a_flags = flags_exclude;
1188                         a->object.flags |= a_flags;
1189                         b->object.flags |= flags;
1190                         add_rev_cmdline(revs, &a->object, this,
1191                                         REV_CMD_LEFT, a_flags);
1192                         add_rev_cmdline(revs, &b->object, next,
1193                                         REV_CMD_RIGHT, flags);
1194                         add_pending_object(revs, &a->object, this);
1195                         add_pending_object(revs, &b->object, next);
1196                         return 0;
1197                 }
1198                 *dotdot = '.';
1199         }
1200         dotdot = strstr(arg, "^@");
1201         if (dotdot && !dotdot[2]) {
1202                 *dotdot = 0;
1203                 if (add_parents_only(revs, arg, flags))
1204                         return 0;
1205                 *dotdot = '^';
1206         }
1207         dotdot = strstr(arg, "^!");
1208         if (dotdot && !dotdot[2]) {
1209                 *dotdot = 0;
1210                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
1211                         *dotdot = '^';
1212         }
1213
1214         local_flags = 0;
1215         if (*arg == '^') {
1216                 local_flags = UNINTERESTING;
1217                 arg++;
1218         }
1219
1220         if (revarg_opt & REVARG_COMMITTISH)
1221                 get_sha1_flags = GET_SHA1_COMMITTISH;
1222
1223         if (get_sha1_with_context(arg, get_sha1_flags, sha1, &oc))
1224                 return revs->ignore_missing ? 0 : -1;
1225         if (!cant_be_filename)
1226                 verify_non_filename(revs->prefix, arg);
1227         object = get_reference(revs, arg, sha1, flags ^ local_flags);
1228         add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
1229         add_pending_object_with_mode(revs, object, arg, oc.mode);
1230         return 0;
1231 }
1232
1233 struct cmdline_pathspec {
1234         int alloc;
1235         int nr;
1236         const char **path;
1237 };
1238
1239 static void append_prune_data(struct cmdline_pathspec *prune, const char **av)
1240 {
1241         while (*av) {
1242                 ALLOC_GROW(prune->path, prune->nr+1, prune->alloc);
1243                 prune->path[prune->nr++] = *(av++);
1244         }
1245 }
1246
1247 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
1248                                      struct cmdline_pathspec *prune)
1249 {
1250         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
1251                 int len = sb->len;
1252                 if (len && sb->buf[len - 1] == '\n')
1253                         sb->buf[--len] = '\0';
1254                 ALLOC_GROW(prune->path, prune->nr+1, prune->alloc);
1255                 prune->path[prune->nr++] = xstrdup(sb->buf);
1256         }
1257 }
1258
1259 static void read_revisions_from_stdin(struct rev_info *revs,
1260                                       struct cmdline_pathspec *prune)
1261 {
1262         struct strbuf sb;
1263         int seen_dashdash = 0;
1264
1265         strbuf_init(&sb, 1000);
1266         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1267                 int len = sb.len;
1268                 if (len && sb.buf[len - 1] == '\n')
1269                         sb.buf[--len] = '\0';
1270                 if (!len)
1271                         break;
1272                 if (sb.buf[0] == '-') {
1273                         if (len == 2 && sb.buf[1] == '-') {
1274                                 seen_dashdash = 1;
1275                                 break;
1276                         }
1277                         die("options not supported in --stdin mode");
1278                 }
1279                 if (handle_revision_arg(sb.buf, revs, 0, REVARG_CANNOT_BE_FILENAME))
1280                         die("bad revision '%s'", sb.buf);
1281         }
1282         if (seen_dashdash)
1283                 read_pathspec_from_stdin(revs, &sb, prune);
1284         strbuf_release(&sb);
1285 }
1286
1287 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1288 {
1289         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1290 }
1291
1292 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1293 {
1294         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1295 }
1296
1297 static void add_message_grep(struct rev_info *revs, const char *pattern)
1298 {
1299         add_grep(revs, pattern, GREP_PATTERN_BODY);
1300 }
1301
1302 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1303                                int *unkc, const char **unkv)
1304 {
1305         const char *arg = argv[0];
1306         const char *optarg;
1307         int argcount;
1308
1309         /* pseudo revision arguments */
1310         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1311             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1312             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1313             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1314             !strcmp(arg, "--bisect") || !prefixcmp(arg, "--glob=") ||
1315             !prefixcmp(arg, "--branches=") || !prefixcmp(arg, "--tags=") ||
1316             !prefixcmp(arg, "--remotes=") || !prefixcmp(arg, "--no-walk="))
1317         {
1318                 unkv[(*unkc)++] = arg;
1319                 return 1;
1320         }
1321
1322         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1323                 revs->max_count = atoi(optarg);
1324                 revs->no_walk = 0;
1325                 return argcount;
1326         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1327                 revs->skip_count = atoi(optarg);
1328                 return argcount;
1329         } else if ((*arg == '-') && isdigit(arg[1])) {
1330         /* accept -<digit>, like traditional "head" */
1331                 revs->max_count = atoi(arg + 1);
1332                 revs->no_walk = 0;
1333         } else if (!strcmp(arg, "-n")) {
1334                 if (argc <= 1)
1335                         return error("-n requires an argument");
1336                 revs->max_count = atoi(argv[1]);
1337                 revs->no_walk = 0;
1338                 return 2;
1339         } else if (!prefixcmp(arg, "-n")) {
1340                 revs->max_count = atoi(arg + 2);
1341                 revs->no_walk = 0;
1342         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1343                 revs->max_age = atoi(optarg);
1344                 return argcount;
1345         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1346                 revs->max_age = approxidate(optarg);
1347                 return argcount;
1348         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1349                 revs->max_age = approxidate(optarg);
1350                 return argcount;
1351         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1352                 revs->min_age = atoi(optarg);
1353                 return argcount;
1354         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1355                 revs->min_age = approxidate(optarg);
1356                 return argcount;
1357         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1358                 revs->min_age = approxidate(optarg);
1359                 return argcount;
1360         } else if (!strcmp(arg, "--first-parent")) {
1361                 revs->first_parent_only = 1;
1362         } else if (!strcmp(arg, "--ancestry-path")) {
1363                 revs->ancestry_path = 1;
1364                 revs->simplify_history = 0;
1365                 revs->limited = 1;
1366         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1367                 init_reflog_walk(&revs->reflog_info);
1368         } else if (!strcmp(arg, "--default")) {
1369                 if (argc <= 1)
1370                         return error("bad --default argument");
1371                 revs->def = argv[1];
1372                 return 2;
1373         } else if (!strcmp(arg, "--merge")) {
1374                 revs->show_merge = 1;
1375         } else if (!strcmp(arg, "--topo-order")) {
1376                 revs->lifo = 1;
1377                 revs->topo_order = 1;
1378         } else if (!strcmp(arg, "--simplify-merges")) {
1379                 revs->simplify_merges = 1;
1380                 revs->topo_order = 1;
1381                 revs->rewrite_parents = 1;
1382                 revs->simplify_history = 0;
1383                 revs->limited = 1;
1384         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1385                 revs->simplify_merges = 1;
1386                 revs->topo_order = 1;
1387                 revs->rewrite_parents = 1;
1388                 revs->simplify_history = 0;
1389                 revs->simplify_by_decoration = 1;
1390                 revs->limited = 1;
1391                 revs->prune = 1;
1392                 load_ref_decorations(DECORATE_SHORT_REFS);
1393         } else if (!strcmp(arg, "--date-order")) {
1394                 revs->lifo = 0;
1395                 revs->topo_order = 1;
1396         } else if (!prefixcmp(arg, "--early-output")) {
1397                 int count = 100;
1398                 switch (arg[14]) {
1399                 case '=':
1400                         count = atoi(arg+15);
1401                         /* Fallthrough */
1402                 case 0:
1403                         revs->topo_order = 1;
1404                        revs->early_output = count;
1405                 }
1406         } else if (!strcmp(arg, "--parents")) {
1407                 revs->rewrite_parents = 1;
1408                 revs->print_parents = 1;
1409         } else if (!strcmp(arg, "--dense")) {
1410                 revs->dense = 1;
1411         } else if (!strcmp(arg, "--sparse")) {
1412                 revs->dense = 0;
1413         } else if (!strcmp(arg, "--show-all")) {
1414                 revs->show_all = 1;
1415         } else if (!strcmp(arg, "--remove-empty")) {
1416                 revs->remove_empty_trees = 1;
1417         } else if (!strcmp(arg, "--merges")) {
1418                 revs->min_parents = 2;
1419         } else if (!strcmp(arg, "--no-merges")) {
1420                 revs->max_parents = 1;
1421         } else if (!prefixcmp(arg, "--min-parents=")) {
1422                 revs->min_parents = atoi(arg+14);
1423         } else if (!prefixcmp(arg, "--no-min-parents")) {
1424                 revs->min_parents = 0;
1425         } else if (!prefixcmp(arg, "--max-parents=")) {
1426                 revs->max_parents = atoi(arg+14);
1427         } else if (!prefixcmp(arg, "--no-max-parents")) {
1428                 revs->max_parents = -1;
1429         } else if (!strcmp(arg, "--boundary")) {
1430                 revs->boundary = 1;
1431         } else if (!strcmp(arg, "--left-right")) {
1432                 revs->left_right = 1;
1433         } else if (!strcmp(arg, "--left-only")) {
1434                 if (revs->right_only)
1435                         die("--left-only is incompatible with --right-only"
1436                             " or --cherry");
1437                 revs->left_only = 1;
1438         } else if (!strcmp(arg, "--right-only")) {
1439                 if (revs->left_only)
1440                         die("--right-only is incompatible with --left-only");
1441                 revs->right_only = 1;
1442         } else if (!strcmp(arg, "--cherry")) {
1443                 if (revs->left_only)
1444                         die("--cherry is incompatible with --left-only");
1445                 revs->cherry_mark = 1;
1446                 revs->right_only = 1;
1447                 revs->max_parents = 1;
1448                 revs->limited = 1;
1449         } else if (!strcmp(arg, "--count")) {
1450                 revs->count = 1;
1451         } else if (!strcmp(arg, "--cherry-mark")) {
1452                 if (revs->cherry_pick)
1453                         die("--cherry-mark is incompatible with --cherry-pick");
1454                 revs->cherry_mark = 1;
1455                 revs->limited = 1; /* needs limit_list() */
1456         } else if (!strcmp(arg, "--cherry-pick")) {
1457                 if (revs->cherry_mark)
1458                         die("--cherry-pick is incompatible with --cherry-mark");
1459                 revs->cherry_pick = 1;
1460                 revs->limited = 1;
1461         } else if (!strcmp(arg, "--objects")) {
1462                 revs->tag_objects = 1;
1463                 revs->tree_objects = 1;
1464                 revs->blob_objects = 1;
1465         } else if (!strcmp(arg, "--objects-edge")) {
1466                 revs->tag_objects = 1;
1467                 revs->tree_objects = 1;
1468                 revs->blob_objects = 1;
1469                 revs->edge_hint = 1;
1470         } else if (!strcmp(arg, "--verify-objects")) {
1471                 revs->tag_objects = 1;
1472                 revs->tree_objects = 1;
1473                 revs->blob_objects = 1;
1474                 revs->verify_objects = 1;
1475         } else if (!strcmp(arg, "--unpacked")) {
1476                 revs->unpacked = 1;
1477         } else if (!prefixcmp(arg, "--unpacked=")) {
1478                 die("--unpacked=<packfile> no longer supported.");
1479         } else if (!strcmp(arg, "-r")) {
1480                 revs->diff = 1;
1481                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1482         } else if (!strcmp(arg, "-t")) {
1483                 revs->diff = 1;
1484                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1485                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1486         } else if (!strcmp(arg, "-m")) {
1487                 revs->ignore_merges = 0;
1488         } else if (!strcmp(arg, "-c")) {
1489                 revs->diff = 1;
1490                 revs->dense_combined_merges = 0;
1491                 revs->combine_merges = 1;
1492         } else if (!strcmp(arg, "--cc")) {
1493                 revs->diff = 1;
1494                 revs->dense_combined_merges = 1;
1495                 revs->combine_merges = 1;
1496         } else if (!strcmp(arg, "-v")) {
1497                 revs->verbose_header = 1;
1498         } else if (!strcmp(arg, "--pretty")) {
1499                 revs->verbose_header = 1;
1500                 revs->pretty_given = 1;
1501                 get_commit_format(arg+8, revs);
1502         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1503                 /*
1504                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1505                  * not allowed, since the argument is optional.
1506                  */
1507                 revs->verbose_header = 1;
1508                 revs->pretty_given = 1;
1509                 get_commit_format(arg+9, revs);
1510         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
1511                 revs->show_notes = 1;
1512                 revs->show_notes_given = 1;
1513                 revs->notes_opt.use_default_notes = 1;
1514         } else if (!strcmp(arg, "--show-signature")) {
1515                 revs->show_signature = 1;
1516         } else if (!prefixcmp(arg, "--show-notes=") ||
1517                    !prefixcmp(arg, "--notes=")) {
1518                 struct strbuf buf = STRBUF_INIT;
1519                 revs->show_notes = 1;
1520                 revs->show_notes_given = 1;
1521                 if (!prefixcmp(arg, "--show-notes")) {
1522                         if (revs->notes_opt.use_default_notes < 0)
1523                                 revs->notes_opt.use_default_notes = 1;
1524                         strbuf_addstr(&buf, arg+13);
1525                 }
1526                 else
1527                         strbuf_addstr(&buf, arg+8);
1528                 expand_notes_ref(&buf);
1529                 string_list_append(&revs->notes_opt.extra_notes_refs,
1530                                    strbuf_detach(&buf, NULL));
1531         } else if (!strcmp(arg, "--no-notes")) {
1532                 revs->show_notes = 0;
1533                 revs->show_notes_given = 1;
1534                 revs->notes_opt.use_default_notes = -1;
1535                 /* we have been strdup'ing ourselves, so trick
1536                  * string_list into free()ing strings */
1537                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
1538                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
1539                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
1540         } else if (!strcmp(arg, "--standard-notes")) {
1541                 revs->show_notes_given = 1;
1542                 revs->notes_opt.use_default_notes = 1;
1543         } else if (!strcmp(arg, "--no-standard-notes")) {
1544                 revs->notes_opt.use_default_notes = 0;
1545         } else if (!strcmp(arg, "--oneline")) {
1546                 revs->verbose_header = 1;
1547                 get_commit_format("oneline", revs);
1548                 revs->pretty_given = 1;
1549                 revs->abbrev_commit = 1;
1550         } else if (!strcmp(arg, "--graph")) {
1551                 revs->topo_order = 1;
1552                 revs->rewrite_parents = 1;
1553                 revs->graph = graph_init(revs);
1554         } else if (!strcmp(arg, "--root")) {
1555                 revs->show_root_diff = 1;
1556         } else if (!strcmp(arg, "--no-commit-id")) {
1557                 revs->no_commit_id = 1;
1558         } else if (!strcmp(arg, "--always")) {
1559                 revs->always_show_header = 1;
1560         } else if (!strcmp(arg, "--no-abbrev")) {
1561                 revs->abbrev = 0;
1562         } else if (!strcmp(arg, "--abbrev")) {
1563                 revs->abbrev = DEFAULT_ABBREV;
1564         } else if (!prefixcmp(arg, "--abbrev=")) {
1565                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1566                 if (revs->abbrev < MINIMUM_ABBREV)
1567                         revs->abbrev = MINIMUM_ABBREV;
1568                 else if (revs->abbrev > 40)
1569                         revs->abbrev = 40;
1570         } else if (!strcmp(arg, "--abbrev-commit")) {
1571                 revs->abbrev_commit = 1;
1572                 revs->abbrev_commit_given = 1;
1573         } else if (!strcmp(arg, "--no-abbrev-commit")) {
1574                 revs->abbrev_commit = 0;
1575         } else if (!strcmp(arg, "--full-diff")) {
1576                 revs->diff = 1;
1577                 revs->full_diff = 1;
1578         } else if (!strcmp(arg, "--full-history")) {
1579                 revs->simplify_history = 0;
1580         } else if (!strcmp(arg, "--relative-date")) {
1581                 revs->date_mode = DATE_RELATIVE;
1582                 revs->date_mode_explicit = 1;
1583         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
1584                 revs->date_mode = parse_date_format(optarg);
1585                 revs->date_mode_explicit = 1;
1586                 return argcount;
1587         } else if (!strcmp(arg, "--log-size")) {
1588                 revs->show_log_size = 1;
1589         }
1590         /*
1591          * Grepping the commit log
1592          */
1593         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
1594                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
1595                 return argcount;
1596         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
1597                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
1598                 return argcount;
1599         } else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
1600                 add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
1601                 return argcount;
1602         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
1603                 add_message_grep(revs, optarg);
1604                 return argcount;
1605         } else if (!strcmp(arg, "--grep-debug")) {
1606                 revs->grep_filter.debug = 1;
1607         } else if (!strcmp(arg, "--basic-regexp")) {
1608                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_BRE, &revs->grep_filter);
1609         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1610                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, &revs->grep_filter);
1611         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1612                 revs->grep_filter.regflags |= REG_ICASE;
1613                 DIFF_OPT_SET(&revs->diffopt, PICKAXE_IGNORE_CASE);
1614         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1615                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_FIXED, &revs->grep_filter);
1616         } else if (!strcmp(arg, "--perl-regexp")) {
1617                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_PCRE, &revs->grep_filter);
1618         } else if (!strcmp(arg, "--all-match")) {
1619                 revs->grep_filter.all_match = 1;
1620         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
1621                 if (strcmp(optarg, "none"))
1622                         git_log_output_encoding = xstrdup(optarg);
1623                 else
1624                         git_log_output_encoding = "";
1625                 return argcount;
1626         } else if (!strcmp(arg, "--reverse")) {
1627                 revs->reverse ^= 1;
1628         } else if (!strcmp(arg, "--children")) {
1629                 revs->children.name = "children";
1630                 revs->limited = 1;
1631         } else if (!strcmp(arg, "--ignore-missing")) {
1632                 revs->ignore_missing = 1;
1633         } else {
1634                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1635                 if (!opts)
1636                         unkv[(*unkc)++] = arg;
1637                 return opts;
1638         }
1639
1640         return 1;
1641 }
1642
1643 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1644                         const struct option *options,
1645                         const char * const usagestr[])
1646 {
1647         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1648                                     &ctx->cpidx, ctx->out);
1649         if (n <= 0) {
1650                 error("unknown option `%s'", ctx->argv[0]);
1651                 usage_with_options(usagestr, options);
1652         }
1653         ctx->argv += n;
1654         ctx->argc -= n;
1655 }
1656
1657 static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1658 {
1659         return for_each_ref_in_submodule(submodule, "refs/bisect/bad", fn, cb_data);
1660 }
1661
1662 static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1663 {
1664         return for_each_ref_in_submodule(submodule, "refs/bisect/good", fn, cb_data);
1665 }
1666
1667 static int handle_revision_pseudo_opt(const char *submodule,
1668                                 struct rev_info *revs,
1669                                 int argc, const char **argv, int *flags)
1670 {
1671         const char *arg = argv[0];
1672         const char *optarg;
1673         int argcount;
1674
1675         /*
1676          * NOTE!
1677          *
1678          * Commands like "git shortlog" will not accept the options below
1679          * unless parse_revision_opt queues them (as opposed to erroring
1680          * out).
1681          *
1682          * When implementing your new pseudo-option, remember to
1683          * register it in the list at the top of handle_revision_opt.
1684          */
1685         if (!strcmp(arg, "--all")) {
1686                 handle_refs(submodule, revs, *flags, for_each_ref_submodule);
1687                 handle_refs(submodule, revs, *flags, head_ref_submodule);
1688         } else if (!strcmp(arg, "--branches")) {
1689                 handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule);
1690         } else if (!strcmp(arg, "--bisect")) {
1691                 handle_refs(submodule, revs, *flags, for_each_bad_bisect_ref);
1692                 handle_refs(submodule, revs, *flags ^ UNINTERESTING, for_each_good_bisect_ref);
1693                 revs->bisect = 1;
1694         } else if (!strcmp(arg, "--tags")) {
1695                 handle_refs(submodule, revs, *flags, for_each_tag_ref_submodule);
1696         } else if (!strcmp(arg, "--remotes")) {
1697                 handle_refs(submodule, revs, *flags, for_each_remote_ref_submodule);
1698         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
1699                 struct all_refs_cb cb;
1700                 init_all_refs_cb(&cb, revs, *flags);
1701                 for_each_glob_ref(handle_one_ref, optarg, &cb);
1702                 return argcount;
1703         } else if (!prefixcmp(arg, "--branches=")) {
1704                 struct all_refs_cb cb;
1705                 init_all_refs_cb(&cb, revs, *flags);
1706                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
1707         } else if (!prefixcmp(arg, "--tags=")) {
1708                 struct all_refs_cb cb;
1709                 init_all_refs_cb(&cb, revs, *flags);
1710                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
1711         } else if (!prefixcmp(arg, "--remotes=")) {
1712                 struct all_refs_cb cb;
1713                 init_all_refs_cb(&cb, revs, *flags);
1714                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
1715         } else if (!strcmp(arg, "--reflog")) {
1716                 handle_reflog(revs, *flags);
1717         } else if (!strcmp(arg, "--not")) {
1718                 *flags ^= UNINTERESTING;
1719         } else if (!strcmp(arg, "--no-walk")) {
1720                 revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
1721         } else if (!prefixcmp(arg, "--no-walk=")) {
1722                 /*
1723                  * Detached form ("--no-walk X" as opposed to "--no-walk=X")
1724                  * not allowed, since the argument is optional.
1725                  */
1726                 if (!strcmp(arg + 10, "sorted"))
1727                         revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
1728                 else if (!strcmp(arg + 10, "unsorted"))
1729                         revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
1730                 else
1731                         return error("invalid argument to --no-walk");
1732         } else if (!strcmp(arg, "--do-walk")) {
1733                 revs->no_walk = 0;
1734         } else {
1735                 return 0;
1736         }
1737
1738         return 1;
1739 }
1740
1741 /*
1742  * Parse revision information, filling in the "rev_info" structure,
1743  * and removing the used arguments from the argument list.
1744  *
1745  * Returns the number of arguments left that weren't recognized
1746  * (which are also moved to the head of the argument list)
1747  */
1748 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
1749 {
1750         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0, revarg_opt;
1751         struct cmdline_pathspec prune_data;
1752         const char *submodule = NULL;
1753
1754         memset(&prune_data, 0, sizeof(prune_data));
1755         if (opt)
1756                 submodule = opt->submodule;
1757
1758         /* First, search for "--" */
1759         if (opt && opt->assume_dashdash) {
1760                 seen_dashdash = 1;
1761         } else {
1762                 seen_dashdash = 0;
1763                 for (i = 1; i < argc; i++) {
1764                         const char *arg = argv[i];
1765                         if (strcmp(arg, "--"))
1766                                 continue;
1767                         argv[i] = NULL;
1768                         argc = i;
1769                         if (argv[i + 1])
1770                                 append_prune_data(&prune_data, argv + i + 1);
1771                         seen_dashdash = 1;
1772                         break;
1773                 }
1774         }
1775
1776         /* Second, deal with arguments and options */
1777         flags = 0;
1778         revarg_opt = opt ? opt->revarg_opt : 0;
1779         if (seen_dashdash)
1780                 revarg_opt |= REVARG_CANNOT_BE_FILENAME;
1781         read_from_stdin = 0;
1782         for (left = i = 1; i < argc; i++) {
1783                 const char *arg = argv[i];
1784                 if (*arg == '-') {
1785                         int opts;
1786
1787                         opts = handle_revision_pseudo_opt(submodule,
1788                                                 revs, argc - i, argv + i,
1789                                                 &flags);
1790                         if (opts > 0) {
1791                                 i += opts - 1;
1792                                 continue;
1793                         }
1794
1795                         if (!strcmp(arg, "--stdin")) {
1796                                 if (revs->disable_stdin) {
1797                                         argv[left++] = arg;
1798                                         continue;
1799                                 }
1800                                 if (read_from_stdin++)
1801                                         die("--stdin given twice?");
1802                                 read_revisions_from_stdin(revs, &prune_data);
1803                                 continue;
1804                         }
1805
1806                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1807                         if (opts > 0) {
1808                                 i += opts - 1;
1809                                 continue;
1810                         }
1811                         if (opts < 0)
1812                                 exit(128);
1813                         continue;
1814                 }
1815
1816
1817                 if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
1818                         int j;
1819                         if (seen_dashdash || *arg == '^')
1820                                 die("bad revision '%s'", arg);
1821
1822                         /* If we didn't have a "--":
1823                          * (1) all filenames must exist;
1824                          * (2) all rev-args must not be interpretable
1825                          *     as a valid filename.
1826                          * but the latter we have checked in the main loop.
1827                          */
1828                         for (j = i; j < argc; j++)
1829                                 verify_filename(revs->prefix, argv[j], j == i);
1830
1831                         append_prune_data(&prune_data, argv + i);
1832                         break;
1833                 }
1834                 else
1835                         got_rev_arg = 1;
1836         }
1837
1838         if (prune_data.nr) {
1839                 /*
1840                  * If we need to introduce the magic "a lone ':' means no
1841                  * pathspec whatsoever", here is the place to do so.
1842                  *
1843                  * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
1844                  *      prune_data.nr = 0;
1845                  *      prune_data.alloc = 0;
1846                  *      free(prune_data.path);
1847                  *      prune_data.path = NULL;
1848                  * } else {
1849                  *      terminate prune_data.alloc with NULL and
1850                  *      call init_pathspec() to set revs->prune_data here.
1851                  * }
1852                  */
1853                 ALLOC_GROW(prune_data.path, prune_data.nr+1, prune_data.alloc);
1854                 prune_data.path[prune_data.nr++] = NULL;
1855                 init_pathspec(&revs->prune_data,
1856                               get_pathspec(revs->prefix, prune_data.path));
1857         }
1858
1859         if (revs->def == NULL)
1860                 revs->def = opt ? opt->def : NULL;
1861         if (opt && opt->tweak)
1862                 opt->tweak(revs, opt);
1863         if (revs->show_merge)
1864                 prepare_show_merge(revs);
1865         if (revs->def && !revs->pending.nr && !got_rev_arg) {
1866                 unsigned char sha1[20];
1867                 struct object *object;
1868                 struct object_context oc;
1869                 if (get_sha1_with_context(revs->def, 0, sha1, &oc))
1870                         die("bad default revision '%s'", revs->def);
1871                 object = get_reference(revs, revs->def, sha1, 0);
1872                 add_pending_object_with_mode(revs, object, revs->def, oc.mode);
1873         }
1874
1875         /* Did the user ask for any diff output? Run the diff! */
1876         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1877                 revs->diff = 1;
1878
1879         /* Pickaxe, diff-filter and rename following need diffs */
1880         if (revs->diffopt.pickaxe ||
1881             revs->diffopt.filter ||
1882             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1883                 revs->diff = 1;
1884
1885         if (revs->topo_order)
1886                 revs->limited = 1;
1887
1888         if (revs->prune_data.nr) {
1889                 diff_tree_setup_paths(revs->prune_data.raw, &revs->pruning);
1890                 /* Can't prune commits with rename following: the paths change.. */
1891                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1892                         revs->prune = 1;
1893                 if (!revs->full_diff)
1894                         diff_tree_setup_paths(revs->prune_data.raw, &revs->diffopt);
1895         }
1896         if (revs->combine_merges)
1897                 revs->ignore_merges = 0;
1898         revs->diffopt.abbrev = revs->abbrev;
1899         diff_setup_done(&revs->diffopt);
1900
1901         grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
1902                                  &revs->grep_filter);
1903         compile_grep_patterns(&revs->grep_filter);
1904
1905         if (revs->reverse && revs->reflog_info)
1906                 die("cannot combine --reverse with --walk-reflogs");
1907         if (revs->rewrite_parents && revs->children.name)
1908                 die("cannot combine --parents and --children");
1909
1910         /*
1911          * Limitations on the graph functionality
1912          */
1913         if (revs->reverse && revs->graph)
1914                 die("cannot combine --reverse with --graph");
1915
1916         if (revs->reflog_info && revs->graph)
1917                 die("cannot combine --walk-reflogs with --graph");
1918         if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
1919                 die("cannot use --grep-reflog without --walk-reflogs");
1920
1921         return left;
1922 }
1923
1924 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1925 {
1926         struct commit_list *l = xcalloc(1, sizeof(*l));
1927
1928         l->item = child;
1929         l->next = add_decoration(&revs->children, &parent->object, l);
1930 }
1931
1932 static int remove_duplicate_parents(struct commit *commit)
1933 {
1934         struct commit_list **pp, *p;
1935         int surviving_parents;
1936
1937         /* Examine existing parents while marking ones we have seen... */
1938         pp = &commit->parents;
1939         while ((p = *pp) != NULL) {
1940                 struct commit *parent = p->item;
1941                 if (parent->object.flags & TMP_MARK) {
1942                         *pp = p->next;
1943                         continue;
1944                 }
1945                 parent->object.flags |= TMP_MARK;
1946                 pp = &p->next;
1947         }
1948         /* count them while clearing the temporary mark */
1949         surviving_parents = 0;
1950         for (p = commit->parents; p; p = p->next) {
1951                 p->item->object.flags &= ~TMP_MARK;
1952                 surviving_parents++;
1953         }
1954         return surviving_parents;
1955 }
1956
1957 struct merge_simplify_state {
1958         struct commit *simplified;
1959 };
1960
1961 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1962 {
1963         struct merge_simplify_state *st;
1964
1965         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1966         if (!st) {
1967                 st = xcalloc(1, sizeof(*st));
1968                 add_decoration(&revs->merge_simplification, &commit->object, st);
1969         }
1970         return st;
1971 }
1972
1973 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1974 {
1975         struct commit_list *p;
1976         struct merge_simplify_state *st, *pst;
1977         int cnt;
1978
1979         st = locate_simplify_state(revs, commit);
1980
1981         /*
1982          * Have we handled this one?
1983          */
1984         if (st->simplified)
1985                 return tail;
1986
1987         /*
1988          * An UNINTERESTING commit simplifies to itself, so does a
1989          * root commit.  We do not rewrite parents of such commit
1990          * anyway.
1991          */
1992         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1993                 st->simplified = commit;
1994                 return tail;
1995         }
1996
1997         /*
1998          * Do we know what commit all of our parents that matter
1999          * should be rewritten to?  Otherwise we are not ready to
2000          * rewrite this one yet.
2001          */
2002         for (cnt = 0, p = commit->parents; p; p = p->next) {
2003                 pst = locate_simplify_state(revs, p->item);
2004                 if (!pst->simplified) {
2005                         tail = &commit_list_insert(p->item, tail)->next;
2006                         cnt++;
2007                 }
2008                 if (revs->first_parent_only)
2009                         break;
2010         }
2011         if (cnt) {
2012                 tail = &commit_list_insert(commit, tail)->next;
2013                 return tail;
2014         }
2015
2016         /*
2017          * Rewrite our list of parents.
2018          */
2019         for (p = commit->parents; p; p = p->next) {
2020                 pst = locate_simplify_state(revs, p->item);
2021                 p->item = pst->simplified;
2022                 if (revs->first_parent_only)
2023                         break;
2024         }
2025
2026         if (revs->first_parent_only)
2027                 cnt = 1;
2028         else
2029                 cnt = remove_duplicate_parents(commit);
2030
2031         /*
2032          * It is possible that we are a merge and one side branch
2033          * does not have any commit that touches the given paths;
2034          * in such a case, the immediate parents will be rewritten
2035          * to different commits.
2036          *
2037          *      o----X          X: the commit we are looking at;
2038          *     /    /           o: a commit that touches the paths;
2039          * ---o----'
2040          *
2041          * Further reduce the parents by removing redundant parents.
2042          */
2043         if (1 < cnt) {
2044                 struct commit_list *h = reduce_heads(commit->parents);
2045                 cnt = commit_list_count(h);
2046                 free_commit_list(commit->parents);
2047                 commit->parents = h;
2048         }
2049
2050         /*
2051          * A commit simplifies to itself if it is a root, if it is
2052          * UNINTERESTING, if it touches the given paths, or if it is a
2053          * merge and its parents simplifies to more than one commits
2054          * (the first two cases are already handled at the beginning of
2055          * this function).
2056          *
2057          * Otherwise, it simplifies to what its sole parent simplifies to.
2058          */
2059         if (!cnt ||
2060             (commit->object.flags & UNINTERESTING) ||
2061             !(commit->object.flags & TREESAME) ||
2062             (1 < cnt))
2063                 st->simplified = commit;
2064         else {
2065                 pst = locate_simplify_state(revs, commit->parents->item);
2066                 st->simplified = pst->simplified;
2067         }
2068         return tail;
2069 }
2070
2071 static void simplify_merges(struct rev_info *revs)
2072 {
2073         struct commit_list *list, *next;
2074         struct commit_list *yet_to_do, **tail;
2075         struct commit *commit;
2076
2077         if (!revs->prune)
2078                 return;
2079
2080         /* feed the list reversed */
2081         yet_to_do = NULL;
2082         for (list = revs->commits; list; list = next) {
2083                 commit = list->item;
2084                 next = list->next;
2085                 /*
2086                  * Do not free(list) here yet; the original list
2087                  * is used later in this function.
2088                  */
2089                 commit_list_insert(commit, &yet_to_do);
2090         }
2091         while (yet_to_do) {
2092                 list = yet_to_do;
2093                 yet_to_do = NULL;
2094                 tail = &yet_to_do;
2095                 while (list) {
2096                         commit = list->item;
2097                         next = list->next;
2098                         free(list);
2099                         list = next;
2100                         tail = simplify_one(revs, commit, tail);
2101                 }
2102         }
2103
2104         /* clean up the result, removing the simplified ones */
2105         list = revs->commits;
2106         revs->commits = NULL;
2107         tail = &revs->commits;
2108         while (list) {
2109                 struct merge_simplify_state *st;
2110
2111                 commit = list->item;
2112                 next = list->next;
2113                 free(list);
2114                 list = next;
2115                 st = locate_simplify_state(revs, commit);
2116                 if (st->simplified == commit)
2117                         tail = &commit_list_insert(commit, tail)->next;
2118         }
2119 }
2120
2121 static void set_children(struct rev_info *revs)
2122 {
2123         struct commit_list *l;
2124         for (l = revs->commits; l; l = l->next) {
2125                 struct commit *commit = l->item;
2126                 struct commit_list *p;
2127
2128                 for (p = commit->parents; p; p = p->next)
2129                         add_child(revs, p->item, commit);
2130         }
2131 }
2132
2133 void reset_revision_walk(void)
2134 {
2135         clear_object_flags(SEEN | ADDED | SHOWN);
2136 }
2137
2138 int prepare_revision_walk(struct rev_info *revs)
2139 {
2140         int nr = revs->pending.nr;
2141         struct object_array_entry *e, *list;
2142         struct commit_list **next = &revs->commits;
2143
2144         e = list = revs->pending.objects;
2145         revs->pending.nr = 0;
2146         revs->pending.alloc = 0;
2147         revs->pending.objects = NULL;
2148         while (--nr >= 0) {
2149                 struct commit *commit = handle_commit(revs, e->item, e->name);
2150                 if (commit) {
2151                         if (!(commit->object.flags & SEEN)) {
2152                                 commit->object.flags |= SEEN;
2153                                 next = commit_list_append(commit, next);
2154                         }
2155                 }
2156                 e++;
2157         }
2158         if (!revs->leak_pending)
2159                 free(list);
2160
2161         if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
2162                 commit_list_sort_by_date(&revs->commits);
2163         if (revs->no_walk)
2164                 return 0;
2165         if (revs->limited)
2166                 if (limit_list(revs) < 0)
2167                         return -1;
2168         if (revs->topo_order)
2169                 sort_in_topological_order(&revs->commits, revs->lifo);
2170         if (revs->simplify_merges)
2171                 simplify_merges(revs);
2172         if (revs->children.name)
2173                 set_children(revs);
2174         return 0;
2175 }
2176
2177 enum rewrite_result {
2178         rewrite_one_ok,
2179         rewrite_one_noparents,
2180         rewrite_one_error
2181 };
2182
2183 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
2184 {
2185         struct commit_list *cache = NULL;
2186
2187         for (;;) {
2188                 struct commit *p = *pp;
2189                 if (!revs->limited)
2190                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
2191                                 return rewrite_one_error;
2192                 if (p->parents && p->parents->next)
2193                         return rewrite_one_ok;
2194                 if (p->object.flags & UNINTERESTING)
2195                         return rewrite_one_ok;
2196                 if (!(p->object.flags & TREESAME))
2197                         return rewrite_one_ok;
2198                 if (!p->parents)
2199                         return rewrite_one_noparents;
2200                 *pp = p->parents->item;
2201         }
2202 }
2203
2204 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
2205 {
2206         struct commit_list **pp = &commit->parents;
2207         while (*pp) {
2208                 struct commit_list *parent = *pp;
2209                 switch (rewrite_one(revs, &parent->item)) {
2210                 case rewrite_one_ok:
2211                         break;
2212                 case rewrite_one_noparents:
2213                         *pp = parent->next;
2214                         continue;
2215                 case rewrite_one_error:
2216                         return -1;
2217                 }
2218                 pp = &parent->next;
2219         }
2220         remove_duplicate_parents(commit);
2221         return 0;
2222 }
2223
2224 static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
2225 {
2226         char *person, *endp;
2227         size_t len, namelen, maillen;
2228         const char *name;
2229         const char *mail;
2230         struct ident_split ident;
2231
2232         person = strstr(buf->buf, what);
2233         if (!person)
2234                 return 0;
2235
2236         person += strlen(what);
2237         endp = strchr(person, '\n');
2238         if (!endp)
2239                 return 0;
2240
2241         len = endp - person;
2242
2243         if (split_ident_line(&ident, person, len))
2244                 return 0;
2245
2246         mail = ident.mail_begin;
2247         maillen = ident.mail_end - ident.mail_begin;
2248         name = ident.name_begin;
2249         namelen = ident.name_end - ident.name_begin;
2250
2251         if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
2252                 struct strbuf namemail = STRBUF_INIT;
2253
2254                 strbuf_addf(&namemail, "%.*s <%.*s>",
2255                             (int)namelen, name, (int)maillen, mail);
2256
2257                 strbuf_splice(buf, ident.name_begin - buf->buf,
2258                               ident.mail_end - ident.name_begin + 1,
2259                               namemail.buf, namemail.len);
2260
2261                 strbuf_release(&namemail);
2262
2263                 return 1;
2264         }
2265
2266         return 0;
2267 }
2268
2269 static int commit_match(struct commit *commit, struct rev_info *opt)
2270 {
2271         int retval;
2272         const char *encoding;
2273         char *message;
2274         struct strbuf buf = STRBUF_INIT;
2275
2276         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
2277                 return 1;
2278
2279         /* Prepend "fake" headers as needed */
2280         if (opt->grep_filter.use_reflog_filter) {
2281                 strbuf_addstr(&buf, "reflog ");
2282                 get_reflog_message(&buf, opt->reflog_info);
2283                 strbuf_addch(&buf, '\n');
2284         }
2285
2286         /*
2287          * We grep in the user's output encoding, under the assumption that it
2288          * is the encoding they are most likely to write their grep pattern
2289          * for. In addition, it means we will match the "notes" encoding below,
2290          * so we will not end up with a buffer that has two different encodings
2291          * in it.
2292          */
2293         encoding = get_log_output_encoding();
2294         message = logmsg_reencode(commit, encoding);
2295
2296         /* Copy the commit to temporary if we are using "fake" headers */
2297         if (buf.len)
2298                 strbuf_addstr(&buf, message);
2299
2300         if (opt->grep_filter.header_list && opt->mailmap) {
2301                 if (!buf.len)
2302                         strbuf_addstr(&buf, message);
2303
2304                 commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
2305                 commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
2306         }
2307
2308         /* Append "fake" message parts as needed */
2309         if (opt->show_notes) {
2310                 if (!buf.len)
2311                         strbuf_addstr(&buf, message);
2312                 format_display_notes(commit->object.sha1, &buf, encoding, 1);
2313         }
2314
2315         /* Find either in the original commit message, or in the temporary */
2316         if (buf.len)
2317                 retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
2318         else
2319                 retval = grep_buffer(&opt->grep_filter,
2320                                      message, strlen(message));
2321         strbuf_release(&buf);
2322         logmsg_free(message, commit);
2323         return retval;
2324 }
2325
2326 static inline int want_ancestry(struct rev_info *revs)
2327 {
2328         return (revs->rewrite_parents || revs->children.name);
2329 }
2330
2331 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
2332 {
2333         if (commit->object.flags & SHOWN)
2334                 return commit_ignore;
2335         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
2336                 return commit_ignore;
2337         if (revs->show_all)
2338                 return commit_show;
2339         if (commit->object.flags & UNINTERESTING)
2340                 return commit_ignore;
2341         if (revs->min_age != -1 && (commit->date > revs->min_age))
2342                 return commit_ignore;
2343         if (revs->min_parents || (revs->max_parents >= 0)) {
2344                 int n = 0;
2345                 struct commit_list *p;
2346                 for (p = commit->parents; p; p = p->next)
2347                         n++;
2348                 if ((n < revs->min_parents) ||
2349                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
2350                         return commit_ignore;
2351         }
2352         if (!commit_match(commit, revs))
2353                 return commit_ignore;
2354         if (revs->prune && revs->dense) {
2355                 /* Commit without changes? */
2356                 if (commit->object.flags & TREESAME) {
2357                         /* drop merges unless we want parenthood */
2358                         if (!want_ancestry(revs))
2359                                 return commit_ignore;
2360                         /* non-merge - always ignore it */
2361                         if (!commit->parents || !commit->parents->next)
2362                                 return commit_ignore;
2363                 }
2364         }
2365         return commit_show;
2366 }
2367
2368 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
2369 {
2370         enum commit_action action = get_commit_action(revs, commit);
2371
2372         if (action == commit_show &&
2373             !revs->show_all &&
2374             revs->prune && revs->dense && want_ancestry(revs)) {
2375                 if (rewrite_parents(revs, commit) < 0)
2376                         return commit_error;
2377         }
2378         return action;
2379 }
2380
2381 static struct commit *get_revision_1(struct rev_info *revs)
2382 {
2383         if (!revs->commits)
2384                 return NULL;
2385
2386         do {
2387                 struct commit_list *entry = revs->commits;
2388                 struct commit *commit = entry->item;
2389
2390                 revs->commits = entry->next;
2391                 free(entry);
2392
2393                 if (revs->reflog_info) {
2394                         fake_reflog_parent(revs->reflog_info, commit);
2395                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
2396                 }
2397
2398                 /*
2399                  * If we haven't done the list limiting, we need to look at
2400                  * the parents here. We also need to do the date-based limiting
2401                  * that we'd otherwise have done in limit_list().
2402                  */
2403                 if (!revs->limited) {
2404                         if (revs->max_age != -1 &&
2405                             (commit->date < revs->max_age))
2406                                 continue;
2407                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
2408                                 die("Failed to traverse parents of commit %s",
2409                                     sha1_to_hex(commit->object.sha1));
2410                 }
2411
2412                 switch (simplify_commit(revs, commit)) {
2413                 case commit_ignore:
2414                         continue;
2415                 case commit_error:
2416                         die("Failed to simplify parents of commit %s",
2417                             sha1_to_hex(commit->object.sha1));
2418                 default:
2419                         return commit;
2420                 }
2421         } while (revs->commits);
2422         return NULL;
2423 }
2424
2425 static void gc_boundary(struct object_array *array)
2426 {
2427         unsigned nr = array->nr;
2428         unsigned alloc = array->alloc;
2429         struct object_array_entry *objects = array->objects;
2430
2431         if (alloc <= nr) {
2432                 unsigned i, j;
2433                 for (i = j = 0; i < nr; i++) {
2434                         if (objects[i].item->flags & SHOWN)
2435                                 continue;
2436                         if (i != j)
2437                                 objects[j] = objects[i];
2438                         j++;
2439                 }
2440                 for (i = j; i < nr; i++)
2441                         objects[i].item = NULL;
2442                 array->nr = j;
2443         }
2444 }
2445
2446 static void create_boundary_commit_list(struct rev_info *revs)
2447 {
2448         unsigned i;
2449         struct commit *c;
2450         struct object_array *array = &revs->boundary_commits;
2451         struct object_array_entry *objects = array->objects;
2452
2453         /*
2454          * If revs->commits is non-NULL at this point, an error occurred in
2455          * get_revision_1().  Ignore the error and continue printing the
2456          * boundary commits anyway.  (This is what the code has always
2457          * done.)
2458          */
2459         if (revs->commits) {
2460                 free_commit_list(revs->commits);
2461                 revs->commits = NULL;
2462         }
2463
2464         /*
2465          * Put all of the actual boundary commits from revs->boundary_commits
2466          * into revs->commits
2467          */
2468         for (i = 0; i < array->nr; i++) {
2469                 c = (struct commit *)(objects[i].item);
2470                 if (!c)
2471                         continue;
2472                 if (!(c->object.flags & CHILD_SHOWN))
2473                         continue;
2474                 if (c->object.flags & (SHOWN | BOUNDARY))
2475                         continue;
2476                 c->object.flags |= BOUNDARY;
2477                 commit_list_insert(c, &revs->commits);
2478         }
2479
2480         /*
2481          * If revs->topo_order is set, sort the boundary commits
2482          * in topological order
2483          */
2484         sort_in_topological_order(&revs->commits, revs->lifo);
2485 }
2486
2487 static struct commit *get_revision_internal(struct rev_info *revs)
2488 {
2489         struct commit *c = NULL;
2490         struct commit_list *l;
2491
2492         if (revs->boundary == 2) {
2493                 /*
2494                  * All of the normal commits have already been returned,
2495                  * and we are now returning boundary commits.
2496                  * create_boundary_commit_list() has populated
2497                  * revs->commits with the remaining commits to return.
2498                  */
2499                 c = pop_commit(&revs->commits);
2500                 if (c)
2501                         c->object.flags |= SHOWN;
2502                 return c;
2503         }
2504
2505         /*
2506          * If our max_count counter has reached zero, then we are done. We
2507          * don't simply return NULL because we still might need to show
2508          * boundary commits. But we want to avoid calling get_revision_1, which
2509          * might do a considerable amount of work finding the next commit only
2510          * for us to throw it away.
2511          *
2512          * If it is non-zero, then either we don't have a max_count at all
2513          * (-1), or it is still counting, in which case we decrement.
2514          */
2515         if (revs->max_count) {
2516                 c = get_revision_1(revs);
2517                 if (c) {
2518                         while (0 < revs->skip_count) {
2519                                 revs->skip_count--;
2520                                 c = get_revision_1(revs);
2521                                 if (!c)
2522                                         break;
2523                         }
2524                 }
2525
2526                 if (revs->max_count > 0)
2527                         revs->max_count--;
2528         }
2529
2530         if (c)
2531                 c->object.flags |= SHOWN;
2532
2533         if (!revs->boundary) {
2534                 return c;
2535         }
2536
2537         if (!c) {
2538                 /*
2539                  * get_revision_1() runs out the commits, and
2540                  * we are done computing the boundaries.
2541                  * switch to boundary commits output mode.
2542                  */
2543                 revs->boundary = 2;
2544
2545                 /*
2546                  * Update revs->commits to contain the list of
2547                  * boundary commits.
2548                  */
2549                 create_boundary_commit_list(revs);
2550
2551                 return get_revision_internal(revs);
2552         }
2553
2554         /*
2555          * boundary commits are the commits that are parents of the
2556          * ones we got from get_revision_1() but they themselves are
2557          * not returned from get_revision_1().  Before returning
2558          * 'c', we need to mark its parents that they could be boundaries.
2559          */
2560
2561         for (l = c->parents; l; l = l->next) {
2562                 struct object *p;
2563                 p = &(l->item->object);
2564                 if (p->flags & (CHILD_SHOWN | SHOWN))
2565                         continue;
2566                 p->flags |= CHILD_SHOWN;
2567                 gc_boundary(&revs->boundary_commits);
2568                 add_object_array(p, NULL, &revs->boundary_commits);
2569         }
2570
2571         return c;
2572 }
2573
2574 struct commit *get_revision(struct rev_info *revs)
2575 {
2576         struct commit *c;
2577         struct commit_list *reversed;
2578
2579         if (revs->reverse) {
2580                 reversed = NULL;
2581                 while ((c = get_revision_internal(revs))) {
2582                         commit_list_insert(c, &reversed);
2583                 }
2584                 revs->commits = reversed;
2585                 revs->reverse = 0;
2586                 revs->reverse_output_stage = 1;
2587         }
2588
2589         if (revs->reverse_output_stage)
2590                 return pop_commit(&revs->commits);
2591
2592         c = get_revision_internal(revs);
2593         if (c && revs->graph)
2594                 graph_update(revs->graph, c);
2595         return c;
2596 }
2597
2598 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
2599 {
2600         if (commit->object.flags & BOUNDARY)
2601                 return "-";
2602         else if (commit->object.flags & UNINTERESTING)
2603                 return "^";
2604         else if (commit->object.flags & PATCHSAME)
2605                 return "=";
2606         else if (!revs || revs->left_right) {
2607                 if (commit->object.flags & SYMMETRIC_LEFT)
2608                         return "<";
2609                 else
2610                         return ">";
2611         } else if (revs->graph)
2612                 return "*";
2613         else if (revs->cherry_mark)
2614                 return "+";
2615         return "";
2616 }
2617
2618 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
2619 {
2620         char *mark = get_revision_mark(revs, commit);
2621         if (!strlen(mark))
2622                 return;
2623         fputs(mark, stdout);
2624         putchar(' ');
2625 }