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