merge --stat: use the full terminal width
[git] / revision.c
1 #include "cache.h"
2 #include "tag.h"
3 #include "blob.h"
4 #include "tree.h"
5 #include "commit.h"
6 #include "diff.h"
7 #include "refs.h"
8 #include "revision.h"
9 #include "graph.h"
10 #include "grep.h"
11 #include "reflog-walk.h"
12 #include "patch-ids.h"
13 #include "decorate.h"
14 #include "log-tree.h"
15 #include "string-list.h"
16
17 volatile show_early_output_fn_t show_early_output;
18
19 char *path_name(const struct name_path *path, const char *name)
20 {
21         const struct name_path *p;
22         char *n, *m;
23         int nlen = strlen(name);
24         int len = nlen + 1;
25
26         for (p = path; p; p = p->up) {
27                 if (p->elem_len)
28                         len += p->elem_len + 1;
29         }
30         n = xmalloc(len);
31         m = n + len - (nlen + 1);
32         strcpy(m, name);
33         for (p = path; p; p = p->up) {
34                 if (p->elem_len) {
35                         m -= p->elem_len + 1;
36                         memcpy(m, p->elem, p->elem_len);
37                         m[p->elem_len] = '/';
38                 }
39         }
40         return n;
41 }
42
43 static int show_path_component_truncated(FILE *out, const char *name, int len)
44 {
45         int cnt;
46         for (cnt = 0; cnt < len; cnt++) {
47                 int ch = name[cnt];
48                 if (!ch || ch == '\n')
49                         return -1;
50                 fputc(ch, out);
51         }
52         return len;
53 }
54
55 static int show_path_truncated(FILE *out, const struct name_path *path)
56 {
57         int emitted, ours;
58
59         if (!path)
60                 return 0;
61         emitted = show_path_truncated(out, path->up);
62         if (emitted < 0)
63                 return emitted;
64         if (emitted)
65                 fputc('/', out);
66         ours = show_path_component_truncated(out, path->elem, path->elem_len);
67         if (ours < 0)
68                 return ours;
69         return ours || emitted;
70 }
71
72 void show_object_with_name(FILE *out, struct object *obj, const struct name_path *path, const char *component)
73 {
74         struct name_path leaf;
75         leaf.up = (struct name_path *)path;
76         leaf.elem = component;
77         leaf.elem_len = strlen(component);
78
79         fprintf(out, "%s ", sha1_to_hex(obj->sha1));
80         show_path_truncated(out, &leaf);
81         fputc('\n', out);
82 }
83
84 void add_object(struct object *obj,
85                 struct object_array *p,
86                 struct name_path *path,
87                 const char *name)
88 {
89         add_object_array(obj, path_name(path, name), p);
90 }
91
92 static void mark_blob_uninteresting(struct blob *blob)
93 {
94         if (!blob)
95                 return;
96         if (blob->object.flags & UNINTERESTING)
97                 return;
98         blob->object.flags |= UNINTERESTING;
99 }
100
101 void mark_tree_uninteresting(struct tree *tree)
102 {
103         struct tree_desc desc;
104         struct name_entry entry;
105         struct object *obj = &tree->object;
106
107         if (!tree)
108                 return;
109         if (obj->flags & UNINTERESTING)
110                 return;
111         obj->flags |= UNINTERESTING;
112         if (!has_sha1_file(obj->sha1))
113                 return;
114         if (parse_tree(tree) < 0)
115                 die("bad tree %s", sha1_to_hex(obj->sha1));
116
117         init_tree_desc(&desc, tree->buffer, tree->size);
118         while (tree_entry(&desc, &entry)) {
119                 switch (object_type(entry.mode)) {
120                 case OBJ_TREE:
121                         mark_tree_uninteresting(lookup_tree(entry.sha1));
122                         break;
123                 case OBJ_BLOB:
124                         mark_blob_uninteresting(lookup_blob(entry.sha1));
125                         break;
126                 default:
127                         /* Subproject commit - not in this repository */
128                         break;
129                 }
130         }
131
132         /*
133          * We don't care about the tree any more
134          * after it has been marked uninteresting.
135          */
136         free(tree->buffer);
137         tree->buffer = NULL;
138 }
139
140 void mark_parents_uninteresting(struct commit *commit)
141 {
142         struct commit_list *parents = commit->parents;
143
144         while (parents) {
145                 struct commit *commit = parents->item;
146                 if (!(commit->object.flags & UNINTERESTING)) {
147                         commit->object.flags |= UNINTERESTING;
148
149                         /*
150                          * Normally we haven't parsed the parent
151                          * yet, so we won't have a parent of a parent
152                          * here. However, it may turn out that we've
153                          * reached this commit some other way (where it
154                          * wasn't uninteresting), in which case we need
155                          * to mark its parents recursively too..
156                          */
157                         if (commit->parents)
158                                 mark_parents_uninteresting(commit);
159                 }
160
161                 /*
162                  * A missing commit is ok iff its parent is marked
163                  * uninteresting.
164                  *
165                  * We just mark such a thing parsed, so that when
166                  * it is popped next time around, we won't be trying
167                  * to parse it and get an error.
168                  */
169                 if (!has_sha1_file(commit->object.sha1))
170                         commit->object.parsed = 1;
171                 parents = parents->next;
172         }
173 }
174
175 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
176 {
177         if (!obj)
178                 return;
179         if (revs->no_walk && (obj->flags & UNINTERESTING))
180                 revs->no_walk = 0;
181         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
182                 struct strbuf buf = STRBUF_INIT;
183                 int len = interpret_branch_name(name, &buf);
184                 int st;
185
186                 if (0 < len && name[len] && buf.len)
187                         strbuf_addstr(&buf, name + len);
188                 st = add_reflog_for_walk(revs->reflog_info,
189                                          (struct commit *)obj,
190                                          buf.buf[0] ? buf.buf: name);
191                 strbuf_release(&buf);
192                 if (st)
193                         return;
194         }
195         add_object_array_with_mode(obj, name, &revs->pending, mode);
196 }
197
198 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
199 {
200         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
201 }
202
203 void add_head_to_pending(struct rev_info *revs)
204 {
205         unsigned char sha1[20];
206         struct object *obj;
207         if (get_sha1("HEAD", sha1))
208                 return;
209         obj = parse_object(sha1);
210         if (!obj)
211                 return;
212         add_pending_object(revs, obj, "HEAD");
213 }
214
215 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
216 {
217         struct object *object;
218
219         object = parse_object(sha1);
220         if (!object) {
221                 if (revs->ignore_missing)
222                         return object;
223                 die("bad object %s", name);
224         }
225         object->flags |= flags;
226         return object;
227 }
228
229 void add_pending_sha1(struct rev_info *revs, const char *name,
230                       const unsigned char *sha1, unsigned int flags)
231 {
232         struct object *object = get_reference(revs, name, sha1, flags);
233         add_pending_object(revs, object, name);
234 }
235
236 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
237 {
238         unsigned long flags = object->flags;
239
240         /*
241          * Tag object? Look what it points to..
242          */
243         while (object->type == OBJ_TAG) {
244                 struct tag *tag = (struct tag *) object;
245                 if (revs->tag_objects && !(flags & UNINTERESTING))
246                         add_pending_object(revs, object, tag->tag);
247                 if (!tag->tagged)
248                         die("bad tag");
249                 object = parse_object(tag->tagged->sha1);
250                 if (!object) {
251                         if (flags & UNINTERESTING)
252                                 return NULL;
253                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
254                 }
255         }
256
257         /*
258          * Commit object? Just return it, we'll do all the complex
259          * reachability crud.
260          */
261         if (object->type == OBJ_COMMIT) {
262                 struct commit *commit = (struct commit *)object;
263                 if (parse_commit(commit) < 0)
264                         die("unable to parse commit %s", name);
265                 if (flags & UNINTERESTING) {
266                         commit->object.flags |= UNINTERESTING;
267                         mark_parents_uninteresting(commit);
268                         revs->limited = 1;
269                 }
270                 if (revs->show_source && !commit->util)
271                         commit->util = (void *) name;
272                 return commit;
273         }
274
275         /*
276          * Tree object? Either mark it uninteresting, or add it
277          * to the list of objects to look at later..
278          */
279         if (object->type == OBJ_TREE) {
280                 struct tree *tree = (struct tree *)object;
281                 if (!revs->tree_objects)
282                         return NULL;
283                 if (flags & UNINTERESTING) {
284                         mark_tree_uninteresting(tree);
285                         return NULL;
286                 }
287                 add_pending_object(revs, object, "");
288                 return NULL;
289         }
290
291         /*
292          * Blob object? You know the drill by now..
293          */
294         if (object->type == OBJ_BLOB) {
295                 struct blob *blob = (struct blob *)object;
296                 if (!revs->blob_objects)
297                         return NULL;
298                 if (flags & UNINTERESTING) {
299                         mark_blob_uninteresting(blob);
300                         return NULL;
301                 }
302                 add_pending_object(revs, object, "");
303                 return NULL;
304         }
305         die("%s is unknown object", name);
306 }
307
308 static int everybody_uninteresting(struct commit_list *orig)
309 {
310         struct commit_list *list = orig;
311         while (list) {
312                 struct commit *commit = list->item;
313                 list = list->next;
314                 if (commit->object.flags & UNINTERESTING)
315                         continue;
316                 return 0;
317         }
318         return 1;
319 }
320
321 /*
322  * The goal is to get REV_TREE_NEW as the result only if the
323  * diff consists of all '+' (and no other changes), REV_TREE_OLD
324  * if the whole diff is removal of old data, and otherwise
325  * REV_TREE_DIFFERENT (of course if the trees are the same we
326  * want REV_TREE_SAME).
327  * That means that once we get to REV_TREE_DIFFERENT, we do not
328  * have to look any further.
329  */
330 static int tree_difference = REV_TREE_SAME;
331
332 static void file_add_remove(struct diff_options *options,
333                     int addremove, unsigned mode,
334                     const unsigned char *sha1,
335                     const char *fullpath, unsigned dirty_submodule)
336 {
337         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
338
339         tree_difference |= diff;
340         if (tree_difference == REV_TREE_DIFFERENT)
341                 DIFF_OPT_SET(options, HAS_CHANGES);
342 }
343
344 static void file_change(struct diff_options *options,
345                  unsigned old_mode, unsigned new_mode,
346                  const unsigned char *old_sha1,
347                  const unsigned char *new_sha1,
348                  const char *fullpath,
349                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
350 {
351         tree_difference = REV_TREE_DIFFERENT;
352         DIFF_OPT_SET(options, HAS_CHANGES);
353 }
354
355 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
356 {
357         struct tree *t1 = parent->tree;
358         struct tree *t2 = commit->tree;
359
360         if (!t1)
361                 return REV_TREE_NEW;
362         if (!t2)
363                 return REV_TREE_OLD;
364
365         if (revs->simplify_by_decoration) {
366                 /*
367                  * If we are simplifying by decoration, then the commit
368                  * is worth showing if it has a tag pointing at it.
369                  */
370                 if (lookup_decoration(&name_decoration, &commit->object))
371                         return REV_TREE_DIFFERENT;
372                 /*
373                  * A commit that is not pointed by a tag is uninteresting
374                  * if we are not limited by path.  This means that you will
375                  * see the usual "commits that touch the paths" plus any
376                  * tagged commit by specifying both --simplify-by-decoration
377                  * and pathspec.
378                  */
379                 if (!revs->prune_data.nr)
380                         return REV_TREE_SAME;
381         }
382
383         tree_difference = REV_TREE_SAME;
384         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
385         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
386                            &revs->pruning) < 0)
387                 return REV_TREE_DIFFERENT;
388         return tree_difference;
389 }
390
391 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
392 {
393         int retval;
394         void *tree;
395         unsigned long size;
396         struct tree_desc empty, real;
397         struct tree *t1 = commit->tree;
398
399         if (!t1)
400                 return 0;
401
402         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
403         if (!tree)
404                 return 0;
405         init_tree_desc(&real, tree, size);
406         init_tree_desc(&empty, "", 0);
407
408         tree_difference = REV_TREE_SAME;
409         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
410         retval = diff_tree(&empty, &real, "", &revs->pruning);
411         free(tree);
412
413         return retval >= 0 && (tree_difference == REV_TREE_SAME);
414 }
415
416 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
417 {
418         struct commit_list **pp, *parent;
419         int tree_changed = 0, tree_same = 0, nth_parent = 0;
420
421         /*
422          * If we don't do pruning, everything is interesting
423          */
424         if (!revs->prune)
425                 return;
426
427         if (!commit->tree)
428                 return;
429
430         if (!commit->parents) {
431                 if (rev_same_tree_as_empty(revs, commit))
432                         commit->object.flags |= TREESAME;
433                 return;
434         }
435
436         /*
437          * Normal non-merge commit? If we don't want to make the
438          * history dense, we consider it always to be a change..
439          */
440         if (!revs->dense && !commit->parents->next)
441                 return;
442
443         pp = &commit->parents;
444         while ((parent = *pp) != NULL) {
445                 struct commit *p = parent->item;
446
447                 /*
448                  * Do not compare with later parents when we care only about
449                  * the first parent chain, in order to avoid derailing the
450                  * traversal to follow a side branch that brought everything
451                  * in the path we are limited to by the pathspec.
452                  */
453                 if (revs->first_parent_only && nth_parent++)
454                         break;
455                 if (parse_commit(p) < 0)
456                         die("cannot simplify commit %s (because of %s)",
457                             sha1_to_hex(commit->object.sha1),
458                             sha1_to_hex(p->object.sha1));
459                 switch (rev_compare_tree(revs, p, commit)) {
460                 case REV_TREE_SAME:
461                         tree_same = 1;
462                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
463                                 /* Even if a merge with an uninteresting
464                                  * side branch brought the entire change
465                                  * we are interested in, we do not want
466                                  * to lose the other branches of this
467                                  * merge, so we just keep going.
468                                  */
469                                 pp = &parent->next;
470                                 continue;
471                         }
472                         parent->next = NULL;
473                         commit->parents = parent;
474                         commit->object.flags |= TREESAME;
475                         return;
476
477                 case REV_TREE_NEW:
478                         if (revs->remove_empty_trees &&
479                             rev_same_tree_as_empty(revs, p)) {
480                                 /* We are adding all the specified
481                                  * paths from this parent, so the
482                                  * history beyond this parent is not
483                                  * interesting.  Remove its parents
484                                  * (they are grandparents for us).
485                                  * IOW, we pretend this parent is a
486                                  * "root" commit.
487                                  */
488                                 if (parse_commit(p) < 0)
489                                         die("cannot simplify commit %s (invalid %s)",
490                                             sha1_to_hex(commit->object.sha1),
491                                             sha1_to_hex(p->object.sha1));
492                                 p->parents = NULL;
493                         }
494                 /* fallthrough */
495                 case REV_TREE_OLD:
496                 case REV_TREE_DIFFERENT:
497                         tree_changed = 1;
498                         pp = &parent->next;
499                         continue;
500                 }
501                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
502         }
503         if (tree_changed && !tree_same)
504                 return;
505         commit->object.flags |= TREESAME;
506 }
507
508 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
509                     struct commit_list *cached_base, struct commit_list **cache)
510 {
511         struct commit_list *new_entry;
512
513         if (cached_base && p->date < cached_base->item->date)
514                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
515         else
516                 new_entry = commit_list_insert_by_date(p, head);
517
518         if (cache && (!*cache || p->date < (*cache)->item->date))
519                 *cache = new_entry;
520 }
521
522 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
523                     struct commit_list **list, struct commit_list **cache_ptr)
524 {
525         struct commit_list *parent = commit->parents;
526         unsigned left_flag;
527         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
528
529         if (commit->object.flags & ADDED)
530                 return 0;
531         commit->object.flags |= ADDED;
532
533         /*
534          * If the commit is uninteresting, don't try to
535          * prune parents - we want the maximal uninteresting
536          * set.
537          *
538          * Normally we haven't parsed the parent
539          * yet, so we won't have a parent of a parent
540          * here. However, it may turn out that we've
541          * reached this commit some other way (where it
542          * wasn't uninteresting), in which case we need
543          * to mark its parents recursively too..
544          */
545         if (commit->object.flags & UNINTERESTING) {
546                 while (parent) {
547                         struct commit *p = parent->item;
548                         parent = parent->next;
549                         if (p)
550                                 p->object.flags |= UNINTERESTING;
551                         if (parse_commit(p) < 0)
552                                 continue;
553                         if (p->parents)
554                                 mark_parents_uninteresting(p);
555                         if (p->object.flags & SEEN)
556                                 continue;
557                         p->object.flags |= SEEN;
558                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
559                 }
560                 return 0;
561         }
562
563         /*
564          * Ok, the commit wasn't uninteresting. Try to
565          * simplify the commit history and find the parent
566          * that has no differences in the path set if one exists.
567          */
568         try_to_simplify_commit(revs, commit);
569
570         if (revs->no_walk)
571                 return 0;
572
573         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
574
575         for (parent = commit->parents; parent; parent = parent->next) {
576                 struct commit *p = parent->item;
577
578                 if (parse_commit(p) < 0)
579                         return -1;
580                 if (revs->show_source && !p->util)
581                         p->util = commit->util;
582                 p->object.flags |= left_flag;
583                 if (!(p->object.flags & SEEN)) {
584                         p->object.flags |= SEEN;
585                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
586                 }
587                 if (revs->first_parent_only)
588                         break;
589         }
590         return 0;
591 }
592
593 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
594 {
595         struct commit_list *p;
596         int left_count = 0, right_count = 0;
597         int left_first;
598         struct patch_ids ids;
599         unsigned cherry_flag;
600
601         /* First count the commits on the left and on the right */
602         for (p = list; p; p = p->next) {
603                 struct commit *commit = p->item;
604                 unsigned flags = commit->object.flags;
605                 if (flags & BOUNDARY)
606                         ;
607                 else if (flags & SYMMETRIC_LEFT)
608                         left_count++;
609                 else
610                         right_count++;
611         }
612
613         if (!left_count || !right_count)
614                 return;
615
616         left_first = left_count < right_count;
617         init_patch_ids(&ids);
618         ids.diffopts.pathspec = revs->diffopt.pathspec;
619
620         /* Compute patch-ids for one side */
621         for (p = list; p; p = p->next) {
622                 struct commit *commit = p->item;
623                 unsigned flags = commit->object.flags;
624
625                 if (flags & BOUNDARY)
626                         continue;
627                 /*
628                  * If we have fewer left, left_first is set and we omit
629                  * commits on the right branch in this loop.  If we have
630                  * fewer right, we skip the left ones.
631                  */
632                 if (left_first != !!(flags & SYMMETRIC_LEFT))
633                         continue;
634                 commit->util = add_commit_patch_id(commit, &ids);
635         }
636
637         /* either cherry_mark or cherry_pick are true */
638         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
639
640         /* Check the other side */
641         for (p = list; p; p = p->next) {
642                 struct commit *commit = p->item;
643                 struct patch_id *id;
644                 unsigned flags = commit->object.flags;
645
646                 if (flags & BOUNDARY)
647                         continue;
648                 /*
649                  * If we have fewer left, left_first is set and we omit
650                  * commits on the left branch in this loop.
651                  */
652                 if (left_first == !!(flags & SYMMETRIC_LEFT))
653                         continue;
654
655                 /*
656                  * Have we seen the same patch id?
657                  */
658                 id = has_commit_patch_id(commit, &ids);
659                 if (!id)
660                         continue;
661                 id->seen = 1;
662                 commit->object.flags |= cherry_flag;
663         }
664
665         /* Now check the original side for seen ones */
666         for (p = list; p; p = p->next) {
667                 struct commit *commit = p->item;
668                 struct patch_id *ent;
669
670                 ent = commit->util;
671                 if (!ent)
672                         continue;
673                 if (ent->seen)
674                         commit->object.flags |= cherry_flag;
675                 commit->util = NULL;
676         }
677
678         free_patch_ids(&ids);
679 }
680
681 /* How many extra uninteresting commits we want to see.. */
682 #define SLOP 5
683
684 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
685 {
686         /*
687          * No source list at all? We're definitely done..
688          */
689         if (!src)
690                 return 0;
691
692         /*
693          * Does the destination list contain entries with a date
694          * before the source list? Definitely _not_ done.
695          */
696         if (date < src->item->date)
697                 return SLOP;
698
699         /*
700          * Does the source list still have interesting commits in
701          * it? Definitely not done..
702          */
703         if (!everybody_uninteresting(src))
704                 return SLOP;
705
706         /* Ok, we're closing in.. */
707         return slop-1;
708 }
709
710 /*
711  * "rev-list --ancestry-path A..B" computes commits that are ancestors
712  * of B but not ancestors of A but further limits the result to those
713  * that are descendants of A.  This takes the list of bottom commits and
714  * the result of "A..B" without --ancestry-path, and limits the latter
715  * further to the ones that can reach one of the commits in "bottom".
716  */
717 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
718 {
719         struct commit_list *p;
720         struct commit_list *rlist = NULL;
721         int made_progress;
722
723         /*
724          * Reverse the list so that it will be likely that we would
725          * process parents before children.
726          */
727         for (p = list; p; p = p->next)
728                 commit_list_insert(p->item, &rlist);
729
730         for (p = bottom; p; p = p->next)
731                 p->item->object.flags |= TMP_MARK;
732
733         /*
734          * Mark the ones that can reach bottom commits in "list",
735          * in a bottom-up fashion.
736          */
737         do {
738                 made_progress = 0;
739                 for (p = rlist; p; p = p->next) {
740                         struct commit *c = p->item;
741                         struct commit_list *parents;
742                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
743                                 continue;
744                         for (parents = c->parents;
745                              parents;
746                              parents = parents->next) {
747                                 if (!(parents->item->object.flags & TMP_MARK))
748                                         continue;
749                                 c->object.flags |= TMP_MARK;
750                                 made_progress = 1;
751                                 break;
752                         }
753                 }
754         } while (made_progress);
755
756         /*
757          * NEEDSWORK: decide if we want to remove parents that are
758          * not marked with TMP_MARK from commit->parents for commits
759          * in the resulting list.  We may not want to do that, though.
760          */
761
762         /*
763          * The ones that are not marked with TMP_MARK are uninteresting
764          */
765         for (p = list; p; p = p->next) {
766                 struct commit *c = p->item;
767                 if (c->object.flags & TMP_MARK)
768                         continue;
769                 c->object.flags |= UNINTERESTING;
770         }
771
772         /* We are done with the TMP_MARK */
773         for (p = list; p; p = p->next)
774                 p->item->object.flags &= ~TMP_MARK;
775         for (p = bottom; p; p = p->next)
776                 p->item->object.flags &= ~TMP_MARK;
777         free_commit_list(rlist);
778 }
779
780 /*
781  * Before walking the history, keep the set of "negative" refs the
782  * caller has asked to exclude.
783  *
784  * This is used to compute "rev-list --ancestry-path A..B", as we need
785  * to filter the result of "A..B" further to the ones that can actually
786  * reach A.
787  */
788 static struct commit_list *collect_bottom_commits(struct rev_info *revs)
789 {
790         struct commit_list *bottom = NULL;
791         int i;
792         for (i = 0; i < revs->cmdline.nr; i++) {
793                 struct rev_cmdline_entry *elem = &revs->cmdline.rev[i];
794                 if ((elem->flags & UNINTERESTING) &&
795                     elem->item->type == OBJ_COMMIT)
796                         commit_list_insert((struct commit *)elem->item, &bottom);
797         }
798         return bottom;
799 }
800
801 /* Assumes either left_only or right_only is set */
802 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
803 {
804         struct commit_list *p;
805
806         for (p = list; p; p = p->next) {
807                 struct commit *commit = p->item;
808
809                 if (revs->right_only) {
810                         if (commit->object.flags & SYMMETRIC_LEFT)
811                                 commit->object.flags |= SHOWN;
812                 } else  /* revs->left_only is set */
813                         if (!(commit->object.flags & SYMMETRIC_LEFT))
814                                 commit->object.flags |= SHOWN;
815         }
816 }
817
818 static int limit_list(struct rev_info *revs)
819 {
820         int slop = SLOP;
821         unsigned long date = ~0ul;
822         struct commit_list *list = revs->commits;
823         struct commit_list *newlist = NULL;
824         struct commit_list **p = &newlist;
825         struct commit_list *bottom = NULL;
826
827         if (revs->ancestry_path) {
828                 bottom = collect_bottom_commits(revs);
829                 if (!bottom)
830                         die("--ancestry-path given but there are no bottom commits");
831         }
832
833         while (list) {
834                 struct commit_list *entry = list;
835                 struct commit *commit = list->item;
836                 struct object *obj = &commit->object;
837                 show_early_output_fn_t show;
838
839                 list = list->next;
840                 free(entry);
841
842                 if (revs->max_age != -1 && (commit->date < revs->max_age))
843                         obj->flags |= UNINTERESTING;
844                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
845                         return -1;
846                 if (obj->flags & UNINTERESTING) {
847                         mark_parents_uninteresting(commit);
848                         if (revs->show_all)
849                                 p = &commit_list_insert(commit, p)->next;
850                         slop = still_interesting(list, date, slop);
851                         if (slop)
852                                 continue;
853                         /* If showing all, add the whole pending list to the end */
854                         if (revs->show_all)
855                                 *p = list;
856                         break;
857                 }
858                 if (revs->min_age != -1 && (commit->date > revs->min_age))
859                         continue;
860                 date = commit->date;
861                 p = &commit_list_insert(commit, p)->next;
862
863                 show = show_early_output;
864                 if (!show)
865                         continue;
866
867                 show(revs, newlist);
868                 show_early_output = NULL;
869         }
870         if (revs->cherry_pick || revs->cherry_mark)
871                 cherry_pick_list(newlist, revs);
872
873         if (revs->left_only || revs->right_only)
874                 limit_left_right(newlist, revs);
875
876         if (bottom) {
877                 limit_to_ancestry(bottom, newlist);
878                 free_commit_list(bottom);
879         }
880
881         revs->commits = newlist;
882         return 0;
883 }
884
885 static void add_rev_cmdline(struct rev_info *revs,
886                             struct object *item,
887                             const char *name,
888                             int whence,
889                             unsigned flags)
890 {
891         struct rev_cmdline_info *info = &revs->cmdline;
892         int nr = info->nr;
893
894         ALLOC_GROW(info->rev, nr + 1, info->alloc);
895         info->rev[nr].item = item;
896         info->rev[nr].name = name;
897         info->rev[nr].whence = whence;
898         info->rev[nr].flags = flags;
899         info->nr++;
900 }
901
902 struct all_refs_cb {
903         int all_flags;
904         int warned_bad_reflog;
905         struct rev_info *all_revs;
906         const char *name_for_errormsg;
907 };
908
909 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
910 {
911         struct all_refs_cb *cb = cb_data;
912         struct object *object = get_reference(cb->all_revs, path, sha1,
913                                               cb->all_flags);
914         add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
915         add_pending_sha1(cb->all_revs, path, sha1, cb->all_flags);
916         return 0;
917 }
918
919 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
920         unsigned flags)
921 {
922         cb->all_revs = revs;
923         cb->all_flags = flags;
924 }
925
926 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
927                 int (*for_each)(const char *, each_ref_fn, void *))
928 {
929         struct all_refs_cb cb;
930         init_all_refs_cb(&cb, revs, flags);
931         for_each(submodule, handle_one_ref, &cb);
932 }
933
934 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
935 {
936         struct all_refs_cb *cb = cb_data;
937         if (!is_null_sha1(sha1)) {
938                 struct object *o = parse_object(sha1);
939                 if (o) {
940                         o->flags |= cb->all_flags;
941                         /* ??? CMDLINEFLAGS ??? */
942                         add_pending_object(cb->all_revs, o, "");
943                 }
944                 else if (!cb->warned_bad_reflog) {
945                         warning("reflog of '%s' references pruned commits",
946                                 cb->name_for_errormsg);
947                         cb->warned_bad_reflog = 1;
948                 }
949         }
950 }
951
952 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
953                 const char *email, unsigned long timestamp, int tz,
954                 const char *message, void *cb_data)
955 {
956         handle_one_reflog_commit(osha1, cb_data);
957         handle_one_reflog_commit(nsha1, cb_data);
958         return 0;
959 }
960
961 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
962 {
963         struct all_refs_cb *cb = cb_data;
964         cb->warned_bad_reflog = 0;
965         cb->name_for_errormsg = path;
966         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
967         return 0;
968 }
969
970 static void handle_reflog(struct rev_info *revs, unsigned flags)
971 {
972         struct all_refs_cb cb;
973         cb.all_revs = revs;
974         cb.all_flags = flags;
975         for_each_reflog(handle_one_reflog, &cb);
976 }
977
978 static int add_parents_only(struct rev_info *revs, const char *arg_, int flags)
979 {
980         unsigned char sha1[20];
981         struct object *it;
982         struct commit *commit;
983         struct commit_list *parents;
984         const char *arg = arg_;
985
986         if (*arg == '^') {
987                 flags ^= UNINTERESTING;
988                 arg++;
989         }
990         if (get_sha1(arg, sha1))
991                 return 0;
992         while (1) {
993                 it = get_reference(revs, arg, sha1, 0);
994                 if (!it && revs->ignore_missing)
995                         return 0;
996                 if (it->type != OBJ_TAG)
997                         break;
998                 if (!((struct tag*)it)->tagged)
999                         return 0;
1000                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
1001         }
1002         if (it->type != OBJ_COMMIT)
1003                 return 0;
1004         commit = (struct commit *)it;
1005         for (parents = commit->parents; parents; parents = parents->next) {
1006                 it = &parents->item->object;
1007                 it->flags |= flags;
1008                 add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
1009                 add_pending_object(revs, it, arg);
1010         }
1011         return 1;
1012 }
1013
1014 void init_revisions(struct rev_info *revs, const char *prefix)
1015 {
1016         memset(revs, 0, sizeof(*revs));
1017
1018         revs->abbrev = DEFAULT_ABBREV;
1019         revs->ignore_merges = 1;
1020         revs->simplify_history = 1;
1021         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
1022         DIFF_OPT_SET(&revs->pruning, QUICK);
1023         revs->pruning.add_remove = file_add_remove;
1024         revs->pruning.change = file_change;
1025         revs->lifo = 1;
1026         revs->dense = 1;
1027         revs->prefix = prefix;
1028         revs->max_age = -1;
1029         revs->min_age = -1;
1030         revs->skip_count = -1;
1031         revs->max_count = -1;
1032         revs->max_parents = -1;
1033
1034         revs->commit_format = CMIT_FMT_DEFAULT;
1035
1036         revs->grep_filter.status_only = 1;
1037         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
1038         revs->grep_filter.header_tail = &(revs->grep_filter.header_list);
1039         revs->grep_filter.regflags = REG_NEWLINE;
1040
1041         diff_setup(&revs->diffopt);
1042         if (prefix && !revs->diffopt.prefix) {
1043                 revs->diffopt.prefix = prefix;
1044                 revs->diffopt.prefix_length = strlen(prefix);
1045         }
1046
1047         revs->notes_opt.use_default_notes = -1;
1048 }
1049
1050 static void add_pending_commit_list(struct rev_info *revs,
1051                                     struct commit_list *commit_list,
1052                                     unsigned int flags)
1053 {
1054         while (commit_list) {
1055                 struct object *object = &commit_list->item->object;
1056                 object->flags |= flags;
1057                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
1058                 commit_list = commit_list->next;
1059         }
1060 }
1061
1062 static void prepare_show_merge(struct rev_info *revs)
1063 {
1064         struct commit_list *bases;
1065         struct commit *head, *other;
1066         unsigned char sha1[20];
1067         const char **prune = NULL;
1068         int i, prune_num = 1; /* counting terminating NULL */
1069
1070         if (get_sha1("HEAD", sha1))
1071                 die("--merge without HEAD?");
1072         head = lookup_commit_or_die(sha1, "HEAD");
1073         if (get_sha1("MERGE_HEAD", sha1))
1074                 die("--merge without MERGE_HEAD?");
1075         other = lookup_commit_or_die(sha1, "MERGE_HEAD");
1076         add_pending_object(revs, &head->object, "HEAD");
1077         add_pending_object(revs, &other->object, "MERGE_HEAD");
1078         bases = get_merge_bases(head, other, 1);
1079         add_pending_commit_list(revs, bases, UNINTERESTING);
1080         free_commit_list(bases);
1081         head->object.flags |= SYMMETRIC_LEFT;
1082
1083         if (!active_nr)
1084                 read_cache();
1085         for (i = 0; i < active_nr; i++) {
1086                 struct cache_entry *ce = active_cache[i];
1087                 if (!ce_stage(ce))
1088                         continue;
1089                 if (ce_path_match(ce, &revs->prune_data)) {
1090                         prune_num++;
1091                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
1092                         prune[prune_num-2] = ce->name;
1093                         prune[prune_num-1] = NULL;
1094                 }
1095                 while ((i+1 < active_nr) &&
1096                        ce_same_name(ce, active_cache[i+1]))
1097                         i++;
1098         }
1099         free_pathspec(&revs->prune_data);
1100         init_pathspec(&revs->prune_data, prune);
1101         revs->limited = 1;
1102 }
1103
1104 int handle_revision_arg(const char *arg_, struct rev_info *revs,
1105                         int flags,
1106                         int cant_be_filename)
1107 {
1108         unsigned mode;
1109         char *dotdot;
1110         struct object *object;
1111         unsigned char sha1[20];
1112         int local_flags;
1113         const char *arg = arg_;
1114
1115         dotdot = strstr(arg, "..");
1116         if (dotdot) {
1117                 unsigned char from_sha1[20];
1118                 const char *next = dotdot + 2;
1119                 const char *this = arg;
1120                 int symmetric = *next == '.';
1121                 unsigned int flags_exclude = flags ^ UNINTERESTING;
1122                 unsigned int a_flags;
1123
1124                 *dotdot = 0;
1125                 next += symmetric;
1126
1127                 if (!*next)
1128                         next = "HEAD";
1129                 if (dotdot == arg)
1130                         this = "HEAD";
1131                 if (!get_sha1(this, from_sha1) &&
1132                     !get_sha1(next, sha1)) {
1133                         struct commit *a, *b;
1134                         struct commit_list *exclude;
1135
1136                         a = lookup_commit_reference(from_sha1);
1137                         b = lookup_commit_reference(sha1);
1138                         if (!a || !b) {
1139                                 if (revs->ignore_missing)
1140                                         return 0;
1141                                 die(symmetric ?
1142                                     "Invalid symmetric difference expression %s...%s" :
1143                                     "Invalid revision range %s..%s",
1144                                     arg, next);
1145                         }
1146
1147                         if (!cant_be_filename) {
1148                                 *dotdot = '.';
1149                                 verify_non_filename(revs->prefix, arg);
1150                         }
1151
1152                         if (symmetric) {
1153                                 exclude = get_merge_bases(a, b, 1);
1154                                 add_pending_commit_list(revs, exclude,
1155                                                         flags_exclude);
1156                                 free_commit_list(exclude);
1157                                 a_flags = flags | SYMMETRIC_LEFT;
1158                         } else
1159                                 a_flags = flags_exclude;
1160                         a->object.flags |= a_flags;
1161                         b->object.flags |= flags;
1162                         add_rev_cmdline(revs, &a->object, this,
1163                                         REV_CMD_LEFT, a_flags);
1164                         add_rev_cmdline(revs, &b->object, next,
1165                                         REV_CMD_RIGHT, flags);
1166                         add_pending_object(revs, &a->object, this);
1167                         add_pending_object(revs, &b->object, next);
1168                         return 0;
1169                 }
1170                 *dotdot = '.';
1171         }
1172         dotdot = strstr(arg, "^@");
1173         if (dotdot && !dotdot[2]) {
1174                 *dotdot = 0;
1175                 if (add_parents_only(revs, arg, flags))
1176                         return 0;
1177                 *dotdot = '^';
1178         }
1179         dotdot = strstr(arg, "^!");
1180         if (dotdot && !dotdot[2]) {
1181                 *dotdot = 0;
1182                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
1183                         *dotdot = '^';
1184         }
1185
1186         local_flags = 0;
1187         if (*arg == '^') {
1188                 local_flags = UNINTERESTING;
1189                 arg++;
1190         }
1191         if (get_sha1_with_mode(arg, sha1, &mode))
1192                 return revs->ignore_missing ? 0 : -1;
1193         if (!cant_be_filename)
1194                 verify_non_filename(revs->prefix, arg);
1195         object = get_reference(revs, arg, sha1, flags ^ local_flags);
1196         add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
1197         add_pending_object_with_mode(revs, object, arg, mode);
1198         return 0;
1199 }
1200
1201 struct cmdline_pathspec {
1202         int alloc;
1203         int nr;
1204         const char **path;
1205 };
1206
1207 static void append_prune_data(struct cmdline_pathspec *prune, const char **av)
1208 {
1209         while (*av) {
1210                 ALLOC_GROW(prune->path, prune->nr+1, prune->alloc);
1211                 prune->path[prune->nr++] = *(av++);
1212         }
1213 }
1214
1215 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
1216                                      struct cmdline_pathspec *prune)
1217 {
1218         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
1219                 int len = sb->len;
1220                 if (len && sb->buf[len - 1] == '\n')
1221                         sb->buf[--len] = '\0';
1222                 ALLOC_GROW(prune->path, prune->nr+1, prune->alloc);
1223                 prune->path[prune->nr++] = xstrdup(sb->buf);
1224         }
1225 }
1226
1227 static void read_revisions_from_stdin(struct rev_info *revs,
1228                                       struct cmdline_pathspec *prune)
1229 {
1230         struct strbuf sb;
1231         int seen_dashdash = 0;
1232
1233         strbuf_init(&sb, 1000);
1234         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1235                 int len = sb.len;
1236                 if (len && sb.buf[len - 1] == '\n')
1237                         sb.buf[--len] = '\0';
1238                 if (!len)
1239                         break;
1240                 if (sb.buf[0] == '-') {
1241                         if (len == 2 && sb.buf[1] == '-') {
1242                                 seen_dashdash = 1;
1243                                 break;
1244                         }
1245                         die("options not supported in --stdin mode");
1246                 }
1247                 if (handle_revision_arg(sb.buf, revs, 0, 1))
1248                         die("bad revision '%s'", sb.buf);
1249         }
1250         if (seen_dashdash)
1251                 read_pathspec_from_stdin(revs, &sb, prune);
1252         strbuf_release(&sb);
1253 }
1254
1255 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1256 {
1257         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1258 }
1259
1260 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1261 {
1262         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1263 }
1264
1265 static void add_message_grep(struct rev_info *revs, const char *pattern)
1266 {
1267         add_grep(revs, pattern, GREP_PATTERN_BODY);
1268 }
1269
1270 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1271                                int *unkc, const char **unkv)
1272 {
1273         const char *arg = argv[0];
1274         const char *optarg;
1275         int argcount;
1276
1277         /* pseudo revision arguments */
1278         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1279             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1280             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1281             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1282             !strcmp(arg, "--bisect") || !prefixcmp(arg, "--glob=") ||
1283             !prefixcmp(arg, "--branches=") || !prefixcmp(arg, "--tags=") ||
1284             !prefixcmp(arg, "--remotes="))
1285         {
1286                 unkv[(*unkc)++] = arg;
1287                 return 1;
1288         }
1289
1290         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1291                 revs->max_count = atoi(optarg);
1292                 revs->no_walk = 0;
1293                 return argcount;
1294         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1295                 revs->skip_count = atoi(optarg);
1296                 return argcount;
1297         } else if ((*arg == '-') && isdigit(arg[1])) {
1298         /* accept -<digit>, like traditional "head" */
1299                 revs->max_count = atoi(arg + 1);
1300                 revs->no_walk = 0;
1301         } else if (!strcmp(arg, "-n")) {
1302                 if (argc <= 1)
1303                         return error("-n requires an argument");
1304                 revs->max_count = atoi(argv[1]);
1305                 revs->no_walk = 0;
1306                 return 2;
1307         } else if (!prefixcmp(arg, "-n")) {
1308                 revs->max_count = atoi(arg + 2);
1309                 revs->no_walk = 0;
1310         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1311                 revs->max_age = atoi(optarg);
1312                 return argcount;
1313         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1314                 revs->max_age = approxidate(optarg);
1315                 return argcount;
1316         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1317                 revs->max_age = approxidate(optarg);
1318                 return argcount;
1319         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1320                 revs->min_age = atoi(optarg);
1321                 return argcount;
1322         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1323                 revs->min_age = approxidate(optarg);
1324                 return argcount;
1325         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1326                 revs->min_age = approxidate(optarg);
1327                 return argcount;
1328         } else if (!strcmp(arg, "--first-parent")) {
1329                 revs->first_parent_only = 1;
1330         } else if (!strcmp(arg, "--ancestry-path")) {
1331                 revs->ancestry_path = 1;
1332                 revs->simplify_history = 0;
1333                 revs->limited = 1;
1334         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1335                 init_reflog_walk(&revs->reflog_info);
1336         } else if (!strcmp(arg, "--default")) {
1337                 if (argc <= 1)
1338                         return error("bad --default argument");
1339                 revs->def = argv[1];
1340                 return 2;
1341         } else if (!strcmp(arg, "--merge")) {
1342                 revs->show_merge = 1;
1343         } else if (!strcmp(arg, "--topo-order")) {
1344                 revs->lifo = 1;
1345                 revs->topo_order = 1;
1346         } else if (!strcmp(arg, "--simplify-merges")) {
1347                 revs->simplify_merges = 1;
1348                 revs->rewrite_parents = 1;
1349                 revs->simplify_history = 0;
1350                 revs->limited = 1;
1351         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1352                 revs->simplify_merges = 1;
1353                 revs->rewrite_parents = 1;
1354                 revs->simplify_history = 0;
1355                 revs->simplify_by_decoration = 1;
1356                 revs->limited = 1;
1357                 revs->prune = 1;
1358                 load_ref_decorations(DECORATE_SHORT_REFS);
1359         } else if (!strcmp(arg, "--date-order")) {
1360                 revs->lifo = 0;
1361                 revs->topo_order = 1;
1362         } else if (!prefixcmp(arg, "--early-output")) {
1363                 int count = 100;
1364                 switch (arg[14]) {
1365                 case '=':
1366                         count = atoi(arg+15);
1367                         /* Fallthrough */
1368                 case 0:
1369                         revs->topo_order = 1;
1370                        revs->early_output = count;
1371                 }
1372         } else if (!strcmp(arg, "--parents")) {
1373                 revs->rewrite_parents = 1;
1374                 revs->print_parents = 1;
1375         } else if (!strcmp(arg, "--dense")) {
1376                 revs->dense = 1;
1377         } else if (!strcmp(arg, "--sparse")) {
1378                 revs->dense = 0;
1379         } else if (!strcmp(arg, "--show-all")) {
1380                 revs->show_all = 1;
1381         } else if (!strcmp(arg, "--remove-empty")) {
1382                 revs->remove_empty_trees = 1;
1383         } else if (!strcmp(arg, "--merges")) {
1384                 revs->min_parents = 2;
1385         } else if (!strcmp(arg, "--no-merges")) {
1386                 revs->max_parents = 1;
1387         } else if (!prefixcmp(arg, "--min-parents=")) {
1388                 revs->min_parents = atoi(arg+14);
1389         } else if (!prefixcmp(arg, "--no-min-parents")) {
1390                 revs->min_parents = 0;
1391         } else if (!prefixcmp(arg, "--max-parents=")) {
1392                 revs->max_parents = atoi(arg+14);
1393         } else if (!prefixcmp(arg, "--no-max-parents")) {
1394                 revs->max_parents = -1;
1395         } else if (!strcmp(arg, "--boundary")) {
1396                 revs->boundary = 1;
1397         } else if (!strcmp(arg, "--left-right")) {
1398                 revs->left_right = 1;
1399         } else if (!strcmp(arg, "--left-only")) {
1400                 if (revs->right_only)
1401                         die("--left-only is incompatible with --right-only"
1402                             " or --cherry");
1403                 revs->left_only = 1;
1404         } else if (!strcmp(arg, "--right-only")) {
1405                 if (revs->left_only)
1406                         die("--right-only is incompatible with --left-only");
1407                 revs->right_only = 1;
1408         } else if (!strcmp(arg, "--cherry")) {
1409                 if (revs->left_only)
1410                         die("--cherry is incompatible with --left-only");
1411                 revs->cherry_mark = 1;
1412                 revs->right_only = 1;
1413                 revs->max_parents = 1;
1414                 revs->limited = 1;
1415         } else if (!strcmp(arg, "--count")) {
1416                 revs->count = 1;
1417         } else if (!strcmp(arg, "--cherry-mark")) {
1418                 if (revs->cherry_pick)
1419                         die("--cherry-mark is incompatible with --cherry-pick");
1420                 revs->cherry_mark = 1;
1421                 revs->limited = 1; /* needs limit_list() */
1422         } else if (!strcmp(arg, "--cherry-pick")) {
1423                 if (revs->cherry_mark)
1424                         die("--cherry-pick is incompatible with --cherry-mark");
1425                 revs->cherry_pick = 1;
1426                 revs->limited = 1;
1427         } else if (!strcmp(arg, "--objects")) {
1428                 revs->tag_objects = 1;
1429                 revs->tree_objects = 1;
1430                 revs->blob_objects = 1;
1431         } else if (!strcmp(arg, "--objects-edge")) {
1432                 revs->tag_objects = 1;
1433                 revs->tree_objects = 1;
1434                 revs->blob_objects = 1;
1435                 revs->edge_hint = 1;
1436         } else if (!strcmp(arg, "--verify-objects")) {
1437                 revs->tag_objects = 1;
1438                 revs->tree_objects = 1;
1439                 revs->blob_objects = 1;
1440                 revs->verify_objects = 1;
1441         } else if (!strcmp(arg, "--unpacked")) {
1442                 revs->unpacked = 1;
1443         } else if (!prefixcmp(arg, "--unpacked=")) {
1444                 die("--unpacked=<packfile> no longer supported.");
1445         } else if (!strcmp(arg, "-r")) {
1446                 revs->diff = 1;
1447                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1448         } else if (!strcmp(arg, "-t")) {
1449                 revs->diff = 1;
1450                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1451                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1452         } else if (!strcmp(arg, "-m")) {
1453                 revs->ignore_merges = 0;
1454         } else if (!strcmp(arg, "-c")) {
1455                 revs->diff = 1;
1456                 revs->dense_combined_merges = 0;
1457                 revs->combine_merges = 1;
1458         } else if (!strcmp(arg, "--cc")) {
1459                 revs->diff = 1;
1460                 revs->dense_combined_merges = 1;
1461                 revs->combine_merges = 1;
1462         } else if (!strcmp(arg, "-v")) {
1463                 revs->verbose_header = 1;
1464         } else if (!strcmp(arg, "--pretty")) {
1465                 revs->verbose_header = 1;
1466                 revs->pretty_given = 1;
1467                 get_commit_format(arg+8, revs);
1468         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1469                 /*
1470                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1471                  * not allowed, since the argument is optional.
1472                  */
1473                 revs->verbose_header = 1;
1474                 revs->pretty_given = 1;
1475                 get_commit_format(arg+9, revs);
1476         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
1477                 revs->show_notes = 1;
1478                 revs->show_notes_given = 1;
1479                 revs->notes_opt.use_default_notes = 1;
1480         } else if (!strcmp(arg, "--show-signature")) {
1481                 revs->show_signature = 1;
1482         } else if (!prefixcmp(arg, "--show-notes=") ||
1483                    !prefixcmp(arg, "--notes=")) {
1484                 struct strbuf buf = STRBUF_INIT;
1485                 revs->show_notes = 1;
1486                 revs->show_notes_given = 1;
1487                 if (!prefixcmp(arg, "--show-notes")) {
1488                         if (revs->notes_opt.use_default_notes < 0)
1489                                 revs->notes_opt.use_default_notes = 1;
1490                         strbuf_addstr(&buf, arg+13);
1491                 }
1492                 else
1493                         strbuf_addstr(&buf, arg+8);
1494                 expand_notes_ref(&buf);
1495                 string_list_append(&revs->notes_opt.extra_notes_refs,
1496                                    strbuf_detach(&buf, NULL));
1497         } else if (!strcmp(arg, "--no-notes")) {
1498                 revs->show_notes = 0;
1499                 revs->show_notes_given = 1;
1500                 revs->notes_opt.use_default_notes = -1;
1501                 /* we have been strdup'ing ourselves, so trick
1502                  * string_list into free()ing strings */
1503                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
1504                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
1505                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
1506         } else if (!strcmp(arg, "--standard-notes")) {
1507                 revs->show_notes_given = 1;
1508                 revs->notes_opt.use_default_notes = 1;
1509         } else if (!strcmp(arg, "--no-standard-notes")) {
1510                 revs->notes_opt.use_default_notes = 0;
1511         } else if (!strcmp(arg, "--oneline")) {
1512                 revs->verbose_header = 1;
1513                 get_commit_format("oneline", revs);
1514                 revs->pretty_given = 1;
1515                 revs->abbrev_commit = 1;
1516         } else if (!strcmp(arg, "--graph")) {
1517                 revs->topo_order = 1;
1518                 revs->rewrite_parents = 1;
1519                 revs->graph = graph_init(revs);
1520         } else if (!strcmp(arg, "--root")) {
1521                 revs->show_root_diff = 1;
1522         } else if (!strcmp(arg, "--no-commit-id")) {
1523                 revs->no_commit_id = 1;
1524         } else if (!strcmp(arg, "--always")) {
1525                 revs->always_show_header = 1;
1526         } else if (!strcmp(arg, "--no-abbrev")) {
1527                 revs->abbrev = 0;
1528         } else if (!strcmp(arg, "--abbrev")) {
1529                 revs->abbrev = DEFAULT_ABBREV;
1530         } else if (!prefixcmp(arg, "--abbrev=")) {
1531                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1532                 if (revs->abbrev < MINIMUM_ABBREV)
1533                         revs->abbrev = MINIMUM_ABBREV;
1534                 else if (revs->abbrev > 40)
1535                         revs->abbrev = 40;
1536         } else if (!strcmp(arg, "--abbrev-commit")) {
1537                 revs->abbrev_commit = 1;
1538                 revs->abbrev_commit_given = 1;
1539         } else if (!strcmp(arg, "--no-abbrev-commit")) {
1540                 revs->abbrev_commit = 0;
1541         } else if (!strcmp(arg, "--full-diff")) {
1542                 revs->diff = 1;
1543                 revs->full_diff = 1;
1544         } else if (!strcmp(arg, "--full-history")) {
1545                 revs->simplify_history = 0;
1546         } else if (!strcmp(arg, "--relative-date")) {
1547                 revs->date_mode = DATE_RELATIVE;
1548                 revs->date_mode_explicit = 1;
1549         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
1550                 revs->date_mode = parse_date_format(optarg);
1551                 revs->date_mode_explicit = 1;
1552                 return argcount;
1553         } else if (!strcmp(arg, "--log-size")) {
1554                 revs->show_log_size = 1;
1555         }
1556         /*
1557          * Grepping the commit log
1558          */
1559         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
1560                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
1561                 return argcount;
1562         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
1563                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
1564                 return argcount;
1565         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
1566                 add_message_grep(revs, optarg);
1567                 return argcount;
1568         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1569                 revs->grep_filter.regflags |= REG_EXTENDED;
1570         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1571                 revs->grep_filter.regflags |= REG_ICASE;
1572         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1573                 revs->grep_filter.fixed = 1;
1574         } else if (!strcmp(arg, "--all-match")) {
1575                 revs->grep_filter.all_match = 1;
1576         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
1577                 if (strcmp(optarg, "none"))
1578                         git_log_output_encoding = xstrdup(optarg);
1579                 else
1580                         git_log_output_encoding = "";
1581                 return argcount;
1582         } else if (!strcmp(arg, "--reverse")) {
1583                 revs->reverse ^= 1;
1584         } else if (!strcmp(arg, "--children")) {
1585                 revs->children.name = "children";
1586                 revs->limited = 1;
1587         } else if (!strcmp(arg, "--ignore-missing")) {
1588                 revs->ignore_missing = 1;
1589         } else {
1590                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1591                 if (!opts)
1592                         unkv[(*unkc)++] = arg;
1593                 return opts;
1594         }
1595
1596         return 1;
1597 }
1598
1599 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1600                         const struct option *options,
1601                         const char * const usagestr[])
1602 {
1603         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1604                                     &ctx->cpidx, ctx->out);
1605         if (n <= 0) {
1606                 error("unknown option `%s'", ctx->argv[0]);
1607                 usage_with_options(usagestr, options);
1608         }
1609         ctx->argv += n;
1610         ctx->argc -= n;
1611 }
1612
1613 static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1614 {
1615         return for_each_ref_in_submodule(submodule, "refs/bisect/bad", fn, cb_data);
1616 }
1617
1618 static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1619 {
1620         return for_each_ref_in_submodule(submodule, "refs/bisect/good", fn, cb_data);
1621 }
1622
1623 static int handle_revision_pseudo_opt(const char *submodule,
1624                                 struct rev_info *revs,
1625                                 int argc, const char **argv, int *flags)
1626 {
1627         const char *arg = argv[0];
1628         const char *optarg;
1629         int argcount;
1630
1631         /*
1632          * NOTE!
1633          *
1634          * Commands like "git shortlog" will not accept the options below
1635          * unless parse_revision_opt queues them (as opposed to erroring
1636          * out).
1637          *
1638          * When implementing your new pseudo-option, remember to
1639          * register it in the list at the top of handle_revision_opt.
1640          */
1641         if (!strcmp(arg, "--all")) {
1642                 handle_refs(submodule, revs, *flags, for_each_ref_submodule);
1643                 handle_refs(submodule, revs, *flags, head_ref_submodule);
1644         } else if (!strcmp(arg, "--branches")) {
1645                 handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule);
1646         } else if (!strcmp(arg, "--bisect")) {
1647                 handle_refs(submodule, revs, *flags, for_each_bad_bisect_ref);
1648                 handle_refs(submodule, revs, *flags ^ UNINTERESTING, for_each_good_bisect_ref);
1649                 revs->bisect = 1;
1650         } else if (!strcmp(arg, "--tags")) {
1651                 handle_refs(submodule, revs, *flags, for_each_tag_ref_submodule);
1652         } else if (!strcmp(arg, "--remotes")) {
1653                 handle_refs(submodule, revs, *flags, for_each_remote_ref_submodule);
1654         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
1655                 struct all_refs_cb cb;
1656                 init_all_refs_cb(&cb, revs, *flags);
1657                 for_each_glob_ref(handle_one_ref, optarg, &cb);
1658                 return argcount;
1659         } else if (!prefixcmp(arg, "--branches=")) {
1660                 struct all_refs_cb cb;
1661                 init_all_refs_cb(&cb, revs, *flags);
1662                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
1663         } else if (!prefixcmp(arg, "--tags=")) {
1664                 struct all_refs_cb cb;
1665                 init_all_refs_cb(&cb, revs, *flags);
1666                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
1667         } else if (!prefixcmp(arg, "--remotes=")) {
1668                 struct all_refs_cb cb;
1669                 init_all_refs_cb(&cb, revs, *flags);
1670                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
1671         } else if (!strcmp(arg, "--reflog")) {
1672                 handle_reflog(revs, *flags);
1673         } else if (!strcmp(arg, "--not")) {
1674                 *flags ^= UNINTERESTING;
1675         } else if (!strcmp(arg, "--no-walk")) {
1676                 revs->no_walk = 1;
1677         } else if (!strcmp(arg, "--do-walk")) {
1678                 revs->no_walk = 0;
1679         } else {
1680                 return 0;
1681         }
1682
1683         return 1;
1684 }
1685
1686 /*
1687  * Parse revision information, filling in the "rev_info" structure,
1688  * and removing the used arguments from the argument list.
1689  *
1690  * Returns the number of arguments left that weren't recognized
1691  * (which are also moved to the head of the argument list)
1692  */
1693 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
1694 {
1695         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0;
1696         struct cmdline_pathspec prune_data;
1697         const char *submodule = NULL;
1698
1699         memset(&prune_data, 0, sizeof(prune_data));
1700         if (opt)
1701                 submodule = opt->submodule;
1702
1703         /* First, search for "--" */
1704         seen_dashdash = 0;
1705         for (i = 1; i < argc; i++) {
1706                 const char *arg = argv[i];
1707                 if (strcmp(arg, "--"))
1708                         continue;
1709                 argv[i] = NULL;
1710                 argc = i;
1711                 if (argv[i + 1])
1712                         append_prune_data(&prune_data, argv + i + 1);
1713                 seen_dashdash = 1;
1714                 break;
1715         }
1716
1717         /* Second, deal with arguments and options */
1718         flags = 0;
1719         read_from_stdin = 0;
1720         for (left = i = 1; i < argc; i++) {
1721                 const char *arg = argv[i];
1722                 if (*arg == '-') {
1723                         int opts;
1724
1725                         opts = handle_revision_pseudo_opt(submodule,
1726                                                 revs, argc - i, argv + i,
1727                                                 &flags);
1728                         if (opts > 0) {
1729                                 i += opts - 1;
1730                                 continue;
1731                         }
1732
1733                         if (!strcmp(arg, "--stdin")) {
1734                                 if (revs->disable_stdin) {
1735                                         argv[left++] = arg;
1736                                         continue;
1737                                 }
1738                                 if (read_from_stdin++)
1739                                         die("--stdin given twice?");
1740                                 read_revisions_from_stdin(revs, &prune_data);
1741                                 continue;
1742                         }
1743
1744                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1745                         if (opts > 0) {
1746                                 i += opts - 1;
1747                                 continue;
1748                         }
1749                         if (opts < 0)
1750                                 exit(128);
1751                         continue;
1752                 }
1753
1754                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1755                         int j;
1756                         if (seen_dashdash || *arg == '^')
1757                                 die("bad revision '%s'", arg);
1758
1759                         /* If we didn't have a "--":
1760                          * (1) all filenames must exist;
1761                          * (2) all rev-args must not be interpretable
1762                          *     as a valid filename.
1763                          * but the latter we have checked in the main loop.
1764                          */
1765                         for (j = i; j < argc; j++)
1766                                 verify_filename(revs->prefix, argv[j]);
1767
1768                         append_prune_data(&prune_data, argv + i);
1769                         break;
1770                 }
1771                 else
1772                         got_rev_arg = 1;
1773         }
1774
1775         if (prune_data.nr) {
1776                 /*
1777                  * If we need to introduce the magic "a lone ':' means no
1778                  * pathspec whatsoever", here is the place to do so.
1779                  *
1780                  * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
1781                  *      prune_data.nr = 0;
1782                  *      prune_data.alloc = 0;
1783                  *      free(prune_data.path);
1784                  *      prune_data.path = NULL;
1785                  * } else {
1786                  *      terminate prune_data.alloc with NULL and
1787                  *      call init_pathspec() to set revs->prune_data here.
1788                  * }
1789                  */
1790                 ALLOC_GROW(prune_data.path, prune_data.nr+1, prune_data.alloc);
1791                 prune_data.path[prune_data.nr++] = NULL;
1792                 init_pathspec(&revs->prune_data,
1793                               get_pathspec(revs->prefix, prune_data.path));
1794         }
1795
1796         if (revs->def == NULL)
1797                 revs->def = opt ? opt->def : NULL;
1798         if (opt && opt->tweak)
1799                 opt->tweak(revs, opt);
1800         if (revs->show_merge)
1801                 prepare_show_merge(revs);
1802         if (revs->def && !revs->pending.nr && !got_rev_arg) {
1803                 unsigned char sha1[20];
1804                 struct object *object;
1805                 unsigned mode;
1806                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1807                         die("bad default revision '%s'", revs->def);
1808                 object = get_reference(revs, revs->def, sha1, 0);
1809                 add_pending_object_with_mode(revs, object, revs->def, mode);
1810         }
1811
1812         /* Did the user ask for any diff output? Run the diff! */
1813         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1814                 revs->diff = 1;
1815
1816         /* Pickaxe, diff-filter and rename following need diffs */
1817         if (revs->diffopt.pickaxe ||
1818             revs->diffopt.filter ||
1819             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1820                 revs->diff = 1;
1821
1822         if (revs->topo_order)
1823                 revs->limited = 1;
1824
1825         if (revs->prune_data.nr) {
1826                 diff_tree_setup_paths(revs->prune_data.raw, &revs->pruning);
1827                 /* Can't prune commits with rename following: the paths change.. */
1828                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1829                         revs->prune = 1;
1830                 if (!revs->full_diff)
1831                         diff_tree_setup_paths(revs->prune_data.raw, &revs->diffopt);
1832         }
1833         if (revs->combine_merges)
1834                 revs->ignore_merges = 0;
1835         revs->diffopt.abbrev = revs->abbrev;
1836         if (diff_setup_done(&revs->diffopt) < 0)
1837                 die("diff_setup_done failed");
1838
1839         compile_grep_patterns(&revs->grep_filter);
1840
1841         if (revs->reverse && revs->reflog_info)
1842                 die("cannot combine --reverse with --walk-reflogs");
1843         if (revs->rewrite_parents && revs->children.name)
1844                 die("cannot combine --parents and --children");
1845
1846         /*
1847          * Limitations on the graph functionality
1848          */
1849         if (revs->reverse && revs->graph)
1850                 die("cannot combine --reverse with --graph");
1851
1852         if (revs->reflog_info && revs->graph)
1853                 die("cannot combine --walk-reflogs with --graph");
1854
1855         return left;
1856 }
1857
1858 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1859 {
1860         struct commit_list *l = xcalloc(1, sizeof(*l));
1861
1862         l->item = child;
1863         l->next = add_decoration(&revs->children, &parent->object, l);
1864 }
1865
1866 static int remove_duplicate_parents(struct commit *commit)
1867 {
1868         struct commit_list **pp, *p;
1869         int surviving_parents;
1870
1871         /* Examine existing parents while marking ones we have seen... */
1872         pp = &commit->parents;
1873         while ((p = *pp) != NULL) {
1874                 struct commit *parent = p->item;
1875                 if (parent->object.flags & TMP_MARK) {
1876                         *pp = p->next;
1877                         continue;
1878                 }
1879                 parent->object.flags |= TMP_MARK;
1880                 pp = &p->next;
1881         }
1882         /* count them while clearing the temporary mark */
1883         surviving_parents = 0;
1884         for (p = commit->parents; p; p = p->next) {
1885                 p->item->object.flags &= ~TMP_MARK;
1886                 surviving_parents++;
1887         }
1888         return surviving_parents;
1889 }
1890
1891 struct merge_simplify_state {
1892         struct commit *simplified;
1893 };
1894
1895 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1896 {
1897         struct merge_simplify_state *st;
1898
1899         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1900         if (!st) {
1901                 st = xcalloc(1, sizeof(*st));
1902                 add_decoration(&revs->merge_simplification, &commit->object, st);
1903         }
1904         return st;
1905 }
1906
1907 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1908 {
1909         struct commit_list *p;
1910         struct merge_simplify_state *st, *pst;
1911         int cnt;
1912
1913         st = locate_simplify_state(revs, commit);
1914
1915         /*
1916          * Have we handled this one?
1917          */
1918         if (st->simplified)
1919                 return tail;
1920
1921         /*
1922          * An UNINTERESTING commit simplifies to itself, so does a
1923          * root commit.  We do not rewrite parents of such commit
1924          * anyway.
1925          */
1926         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1927                 st->simplified = commit;
1928                 return tail;
1929         }
1930
1931         /*
1932          * Do we know what commit all of our parents should be rewritten to?
1933          * Otherwise we are not ready to rewrite this one yet.
1934          */
1935         for (cnt = 0, p = commit->parents; p; p = p->next) {
1936                 pst = locate_simplify_state(revs, p->item);
1937                 if (!pst->simplified) {
1938                         tail = &commit_list_insert(p->item, tail)->next;
1939                         cnt++;
1940                 }
1941         }
1942         if (cnt) {
1943                 tail = &commit_list_insert(commit, tail)->next;
1944                 return tail;
1945         }
1946
1947         /*
1948          * Rewrite our list of parents.
1949          */
1950         for (p = commit->parents; p; p = p->next) {
1951                 pst = locate_simplify_state(revs, p->item);
1952                 p->item = pst->simplified;
1953         }
1954         cnt = remove_duplicate_parents(commit);
1955
1956         /*
1957          * It is possible that we are a merge and one side branch
1958          * does not have any commit that touches the given paths;
1959          * in such a case, the immediate parents will be rewritten
1960          * to different commits.
1961          *
1962          *      o----X          X: the commit we are looking at;
1963          *     /    /           o: a commit that touches the paths;
1964          * ---o----'
1965          *
1966          * Further reduce the parents by removing redundant parents.
1967          */
1968         if (1 < cnt) {
1969                 struct commit_list *h = reduce_heads(commit->parents);
1970                 cnt = commit_list_count(h);
1971                 free_commit_list(commit->parents);
1972                 commit->parents = h;
1973         }
1974
1975         /*
1976          * A commit simplifies to itself if it is a root, if it is
1977          * UNINTERESTING, if it touches the given paths, or if it is a
1978          * merge and its parents simplifies to more than one commits
1979          * (the first two cases are already handled at the beginning of
1980          * this function).
1981          *
1982          * Otherwise, it simplifies to what its sole parent simplifies to.
1983          */
1984         if (!cnt ||
1985             (commit->object.flags & UNINTERESTING) ||
1986             !(commit->object.flags & TREESAME) ||
1987             (1 < cnt))
1988                 st->simplified = commit;
1989         else {
1990                 pst = locate_simplify_state(revs, commit->parents->item);
1991                 st->simplified = pst->simplified;
1992         }
1993         return tail;
1994 }
1995
1996 static void simplify_merges(struct rev_info *revs)
1997 {
1998         struct commit_list *list;
1999         struct commit_list *yet_to_do, **tail;
2000
2001         if (!revs->topo_order)
2002                 sort_in_topological_order(&revs->commits, revs->lifo);
2003         if (!revs->prune)
2004                 return;
2005
2006         /* feed the list reversed */
2007         yet_to_do = NULL;
2008         for (list = revs->commits; list; list = list->next)
2009                 commit_list_insert(list->item, &yet_to_do);
2010         while (yet_to_do) {
2011                 list = yet_to_do;
2012                 yet_to_do = NULL;
2013                 tail = &yet_to_do;
2014                 while (list) {
2015                         struct commit *commit = list->item;
2016                         struct commit_list *next = list->next;
2017                         free(list);
2018                         list = next;
2019                         tail = simplify_one(revs, commit, tail);
2020                 }
2021         }
2022
2023         /* clean up the result, removing the simplified ones */
2024         list = revs->commits;
2025         revs->commits = NULL;
2026         tail = &revs->commits;
2027         while (list) {
2028                 struct commit *commit = list->item;
2029                 struct commit_list *next = list->next;
2030                 struct merge_simplify_state *st;
2031                 free(list);
2032                 list = next;
2033                 st = locate_simplify_state(revs, commit);
2034                 if (st->simplified == commit)
2035                         tail = &commit_list_insert(commit, tail)->next;
2036         }
2037 }
2038
2039 static void set_children(struct rev_info *revs)
2040 {
2041         struct commit_list *l;
2042         for (l = revs->commits; l; l = l->next) {
2043                 struct commit *commit = l->item;
2044                 struct commit_list *p;
2045
2046                 for (p = commit->parents; p; p = p->next)
2047                         add_child(revs, p->item, commit);
2048         }
2049 }
2050
2051 int prepare_revision_walk(struct rev_info *revs)
2052 {
2053         int nr = revs->pending.nr;
2054         struct object_array_entry *e, *list;
2055
2056         e = list = revs->pending.objects;
2057         revs->pending.nr = 0;
2058         revs->pending.alloc = 0;
2059         revs->pending.objects = NULL;
2060         while (--nr >= 0) {
2061                 struct commit *commit = handle_commit(revs, e->item, e->name);
2062                 if (commit) {
2063                         if (!(commit->object.flags & SEEN)) {
2064                                 commit->object.flags |= SEEN;
2065                                 commit_list_insert_by_date(commit, &revs->commits);
2066                         }
2067                 }
2068                 e++;
2069         }
2070         if (!revs->leak_pending)
2071                 free(list);
2072
2073         if (revs->no_walk)
2074                 return 0;
2075         if (revs->limited)
2076                 if (limit_list(revs) < 0)
2077                         return -1;
2078         if (revs->topo_order)
2079                 sort_in_topological_order(&revs->commits, revs->lifo);
2080         if (revs->simplify_merges)
2081                 simplify_merges(revs);
2082         if (revs->children.name)
2083                 set_children(revs);
2084         return 0;
2085 }
2086
2087 enum rewrite_result {
2088         rewrite_one_ok,
2089         rewrite_one_noparents,
2090         rewrite_one_error
2091 };
2092
2093 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
2094 {
2095         struct commit_list *cache = NULL;
2096
2097         for (;;) {
2098                 struct commit *p = *pp;
2099                 if (!revs->limited)
2100                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
2101                                 return rewrite_one_error;
2102                 if (p->parents && p->parents->next)
2103                         return rewrite_one_ok;
2104                 if (p->object.flags & UNINTERESTING)
2105                         return rewrite_one_ok;
2106                 if (!(p->object.flags & TREESAME))
2107                         return rewrite_one_ok;
2108                 if (!p->parents)
2109                         return rewrite_one_noparents;
2110                 *pp = p->parents->item;
2111         }
2112 }
2113
2114 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
2115 {
2116         struct commit_list **pp = &commit->parents;
2117         while (*pp) {
2118                 struct commit_list *parent = *pp;
2119                 switch (rewrite_one(revs, &parent->item)) {
2120                 case rewrite_one_ok:
2121                         break;
2122                 case rewrite_one_noparents:
2123                         *pp = parent->next;
2124                         continue;
2125                 case rewrite_one_error:
2126                         return -1;
2127                 }
2128                 pp = &parent->next;
2129         }
2130         remove_duplicate_parents(commit);
2131         return 0;
2132 }
2133
2134 static int commit_match(struct commit *commit, struct rev_info *opt)
2135 {
2136         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
2137                 return 1;
2138         return grep_buffer(&opt->grep_filter,
2139                            NULL, /* we say nothing, not even filename */
2140                            commit->buffer, strlen(commit->buffer));
2141 }
2142
2143 static inline int want_ancestry(struct rev_info *revs)
2144 {
2145         return (revs->rewrite_parents || revs->children.name);
2146 }
2147
2148 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
2149 {
2150         if (commit->object.flags & SHOWN)
2151                 return commit_ignore;
2152         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
2153                 return commit_ignore;
2154         if (revs->show_all)
2155                 return commit_show;
2156         if (commit->object.flags & UNINTERESTING)
2157                 return commit_ignore;
2158         if (revs->min_age != -1 && (commit->date > revs->min_age))
2159                 return commit_ignore;
2160         if (revs->min_parents || (revs->max_parents >= 0)) {
2161                 int n = 0;
2162                 struct commit_list *p;
2163                 for (p = commit->parents; p; p = p->next)
2164                         n++;
2165                 if ((n < revs->min_parents) ||
2166                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
2167                         return commit_ignore;
2168         }
2169         if (!commit_match(commit, revs))
2170                 return commit_ignore;
2171         if (revs->prune && revs->dense) {
2172                 /* Commit without changes? */
2173                 if (commit->object.flags & TREESAME) {
2174                         /* drop merges unless we want parenthood */
2175                         if (!want_ancestry(revs))
2176                                 return commit_ignore;
2177                         /* non-merge - always ignore it */
2178                         if (!commit->parents || !commit->parents->next)
2179                                 return commit_ignore;
2180                 }
2181         }
2182         return commit_show;
2183 }
2184
2185 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
2186 {
2187         enum commit_action action = get_commit_action(revs, commit);
2188
2189         if (action == commit_show &&
2190             !revs->show_all &&
2191             revs->prune && revs->dense && want_ancestry(revs)) {
2192                 if (rewrite_parents(revs, commit) < 0)
2193                         return commit_error;
2194         }
2195         return action;
2196 }
2197
2198 static struct commit *get_revision_1(struct rev_info *revs)
2199 {
2200         if (!revs->commits)
2201                 return NULL;
2202
2203         do {
2204                 struct commit_list *entry = revs->commits;
2205                 struct commit *commit = entry->item;
2206
2207                 revs->commits = entry->next;
2208                 free(entry);
2209
2210                 if (revs->reflog_info) {
2211                         fake_reflog_parent(revs->reflog_info, commit);
2212                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
2213                 }
2214
2215                 /*
2216                  * If we haven't done the list limiting, we need to look at
2217                  * the parents here. We also need to do the date-based limiting
2218                  * that we'd otherwise have done in limit_list().
2219                  */
2220                 if (!revs->limited) {
2221                         if (revs->max_age != -1 &&
2222                             (commit->date < revs->max_age))
2223                                 continue;
2224                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
2225                                 die("Failed to traverse parents of commit %s",
2226                                     sha1_to_hex(commit->object.sha1));
2227                 }
2228
2229                 switch (simplify_commit(revs, commit)) {
2230                 case commit_ignore:
2231                         continue;
2232                 case commit_error:
2233                         die("Failed to simplify parents of commit %s",
2234                             sha1_to_hex(commit->object.sha1));
2235                 default:
2236                         return commit;
2237                 }
2238         } while (revs->commits);
2239         return NULL;
2240 }
2241
2242 static void gc_boundary(struct object_array *array)
2243 {
2244         unsigned nr = array->nr;
2245         unsigned alloc = array->alloc;
2246         struct object_array_entry *objects = array->objects;
2247
2248         if (alloc <= nr) {
2249                 unsigned i, j;
2250                 for (i = j = 0; i < nr; i++) {
2251                         if (objects[i].item->flags & SHOWN)
2252                                 continue;
2253                         if (i != j)
2254                                 objects[j] = objects[i];
2255                         j++;
2256                 }
2257                 for (i = j; i < nr; i++)
2258                         objects[i].item = NULL;
2259                 array->nr = j;
2260         }
2261 }
2262
2263 static void create_boundary_commit_list(struct rev_info *revs)
2264 {
2265         unsigned i;
2266         struct commit *c;
2267         struct object_array *array = &revs->boundary_commits;
2268         struct object_array_entry *objects = array->objects;
2269
2270         /*
2271          * If revs->commits is non-NULL at this point, an error occurred in
2272          * get_revision_1().  Ignore the error and continue printing the
2273          * boundary commits anyway.  (This is what the code has always
2274          * done.)
2275          */
2276         if (revs->commits) {
2277                 free_commit_list(revs->commits);
2278                 revs->commits = NULL;
2279         }
2280
2281         /*
2282          * Put all of the actual boundary commits from revs->boundary_commits
2283          * into revs->commits
2284          */
2285         for (i = 0; i < array->nr; i++) {
2286                 c = (struct commit *)(objects[i].item);
2287                 if (!c)
2288                         continue;
2289                 if (!(c->object.flags & CHILD_SHOWN))
2290                         continue;
2291                 if (c->object.flags & (SHOWN | BOUNDARY))
2292                         continue;
2293                 c->object.flags |= BOUNDARY;
2294                 commit_list_insert(c, &revs->commits);
2295         }
2296
2297         /*
2298          * If revs->topo_order is set, sort the boundary commits
2299          * in topological order
2300          */
2301         sort_in_topological_order(&revs->commits, revs->lifo);
2302 }
2303
2304 static struct commit *get_revision_internal(struct rev_info *revs)
2305 {
2306         struct commit *c = NULL;
2307         struct commit_list *l;
2308
2309         if (revs->boundary == 2) {
2310                 /*
2311                  * All of the normal commits have already been returned,
2312                  * and we are now returning boundary commits.
2313                  * create_boundary_commit_list() has populated
2314                  * revs->commits with the remaining commits to return.
2315                  */
2316                 c = pop_commit(&revs->commits);
2317                 if (c)
2318                         c->object.flags |= SHOWN;
2319                 return c;
2320         }
2321
2322         /*
2323          * Now pick up what they want to give us
2324          */
2325         c = get_revision_1(revs);
2326         if (c) {
2327                 while (0 < revs->skip_count) {
2328                         revs->skip_count--;
2329                         c = get_revision_1(revs);
2330                         if (!c)
2331                                 break;
2332                 }
2333         }
2334
2335         /*
2336          * Check the max_count.
2337          */
2338         switch (revs->max_count) {
2339         case -1:
2340                 break;
2341         case 0:
2342                 c = NULL;
2343                 break;
2344         default:
2345                 revs->max_count--;
2346         }
2347
2348         if (c)
2349                 c->object.flags |= SHOWN;
2350
2351         if (!revs->boundary) {
2352                 return c;
2353         }
2354
2355         if (!c) {
2356                 /*
2357                  * get_revision_1() runs out the commits, and
2358                  * we are done computing the boundaries.
2359                  * switch to boundary commits output mode.
2360                  */
2361                 revs->boundary = 2;
2362
2363                 /*
2364                  * Update revs->commits to contain the list of
2365                  * boundary commits.
2366                  */
2367                 create_boundary_commit_list(revs);
2368
2369                 return get_revision_internal(revs);
2370         }
2371
2372         /*
2373          * boundary commits are the commits that are parents of the
2374          * ones we got from get_revision_1() but they themselves are
2375          * not returned from get_revision_1().  Before returning
2376          * 'c', we need to mark its parents that they could be boundaries.
2377          */
2378
2379         for (l = c->parents; l; l = l->next) {
2380                 struct object *p;
2381                 p = &(l->item->object);
2382                 if (p->flags & (CHILD_SHOWN | SHOWN))
2383                         continue;
2384                 p->flags |= CHILD_SHOWN;
2385                 gc_boundary(&revs->boundary_commits);
2386                 add_object_array(p, NULL, &revs->boundary_commits);
2387         }
2388
2389         return c;
2390 }
2391
2392 struct commit *get_revision(struct rev_info *revs)
2393 {
2394         struct commit *c;
2395         struct commit_list *reversed;
2396
2397         if (revs->reverse) {
2398                 reversed = NULL;
2399                 while ((c = get_revision_internal(revs))) {
2400                         commit_list_insert(c, &reversed);
2401                 }
2402                 revs->commits = reversed;
2403                 revs->reverse = 0;
2404                 revs->reverse_output_stage = 1;
2405         }
2406
2407         if (revs->reverse_output_stage)
2408                 return pop_commit(&revs->commits);
2409
2410         c = get_revision_internal(revs);
2411         if (c && revs->graph)
2412                 graph_update(revs->graph, c);
2413         return c;
2414 }
2415
2416 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
2417 {
2418         if (commit->object.flags & BOUNDARY)
2419                 return "-";
2420         else if (commit->object.flags & UNINTERESTING)
2421                 return "^";
2422         else if (commit->object.flags & PATCHSAME)
2423                 return "=";
2424         else if (!revs || revs->left_right) {
2425                 if (commit->object.flags & SYMMETRIC_LEFT)
2426                         return "<";
2427                 else
2428                         return ">";
2429         } else if (revs->graph)
2430                 return "*";
2431         else if (revs->cherry_mark)
2432                 return "+";
2433         return "";
2434 }
2435
2436 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
2437 {
2438         char *mark = get_revision_mark(revs, commit);
2439         if (!strlen(mark))
2440                 return;
2441         fputs(mark, stdout);
2442         putchar(' ');
2443 }