Merge branch 'jc/t1506-shell-param-expansion-gotcha'
[git] / revision.c
1 #include "cache.h"
2 #include "tag.h"
3 #include "blob.h"
4 #include "tree.h"
5 #include "commit.h"
6 #include "diff.h"
7 #include "refs.h"
8 #include "revision.h"
9 #include "graph.h"
10 #include "grep.h"
11 #include "reflog-walk.h"
12 #include "patch-ids.h"
13 #include "decorate.h"
14 #include "log-tree.h"
15 #include "string-list.h"
16
17 volatile show_early_output_fn_t show_early_output;
18
19 char *path_name(const struct name_path *path, const char *name)
20 {
21         const struct name_path *p;
22         char *n, *m;
23         int nlen = strlen(name);
24         int len = nlen + 1;
25
26         for (p = path; p; p = p->up) {
27                 if (p->elem_len)
28                         len += p->elem_len + 1;
29         }
30         n = xmalloc(len);
31         m = n + len - (nlen + 1);
32         strcpy(m, name);
33         for (p = path; p; p = p->up) {
34                 if (p->elem_len) {
35                         m -= p->elem_len + 1;
36                         memcpy(m, p->elem, p->elem_len);
37                         m[p->elem_len] = '/';
38                 }
39         }
40         return n;
41 }
42
43 void add_object(struct object *obj,
44                 struct object_array *p,
45                 struct name_path *path,
46                 const char *name)
47 {
48         add_object_array(obj, path_name(path, name), p);
49 }
50
51 static void mark_blob_uninteresting(struct blob *blob)
52 {
53         if (!blob)
54                 return;
55         if (blob->object.flags & UNINTERESTING)
56                 return;
57         blob->object.flags |= UNINTERESTING;
58 }
59
60 void mark_tree_uninteresting(struct tree *tree)
61 {
62         struct tree_desc desc;
63         struct name_entry entry;
64         struct object *obj = &tree->object;
65
66         if (!tree)
67                 return;
68         if (obj->flags & UNINTERESTING)
69                 return;
70         obj->flags |= UNINTERESTING;
71         if (!has_sha1_file(obj->sha1))
72                 return;
73         if (parse_tree(tree) < 0)
74                 die("bad tree %s", sha1_to_hex(obj->sha1));
75
76         init_tree_desc(&desc, tree->buffer, tree->size);
77         while (tree_entry(&desc, &entry)) {
78                 switch (object_type(entry.mode)) {
79                 case OBJ_TREE:
80                         mark_tree_uninteresting(lookup_tree(entry.sha1));
81                         break;
82                 case OBJ_BLOB:
83                         mark_blob_uninteresting(lookup_blob(entry.sha1));
84                         break;
85                 default:
86                         /* Subproject commit - not in this repository */
87                         break;
88                 }
89         }
90
91         /*
92          * We don't care about the tree any more
93          * after it has been marked uninteresting.
94          */
95         free(tree->buffer);
96         tree->buffer = NULL;
97 }
98
99 void mark_parents_uninteresting(struct commit *commit)
100 {
101         struct commit_list *parents = commit->parents;
102
103         while (parents) {
104                 struct commit *commit = parents->item;
105                 if (!(commit->object.flags & UNINTERESTING)) {
106                         commit->object.flags |= UNINTERESTING;
107
108                         /*
109                          * Normally we haven't parsed the parent
110                          * yet, so we won't have a parent of a parent
111                          * here. However, it may turn out that we've
112                          * reached this commit some other way (where it
113                          * wasn't uninteresting), in which case we need
114                          * to mark its parents recursively too..
115                          */
116                         if (commit->parents)
117                                 mark_parents_uninteresting(commit);
118                 }
119
120                 /*
121                  * A missing commit is ok iff its parent is marked
122                  * uninteresting.
123                  *
124                  * We just mark such a thing parsed, so that when
125                  * it is popped next time around, we won't be trying
126                  * to parse it and get an error.
127                  */
128                 if (!has_sha1_file(commit->object.sha1))
129                         commit->object.parsed = 1;
130                 parents = parents->next;
131         }
132 }
133
134 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
135 {
136         if (revs->no_walk && (obj->flags & UNINTERESTING))
137                 revs->no_walk = 0;
138         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
139                 struct strbuf buf = STRBUF_INIT;
140                 int len = interpret_branch_name(name, &buf);
141                 int st;
142
143                 if (0 < len && name[len] && buf.len)
144                         strbuf_addstr(&buf, name + len);
145                 st = add_reflog_for_walk(revs->reflog_info,
146                                          (struct commit *)obj,
147                                          buf.buf[0] ? buf.buf: name);
148                 strbuf_release(&buf);
149                 if (st)
150                         return;
151         }
152         add_object_array_with_mode(obj, name, &revs->pending, mode);
153 }
154
155 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
156 {
157         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
158 }
159
160 void add_head_to_pending(struct rev_info *revs)
161 {
162         unsigned char sha1[20];
163         struct object *obj;
164         if (get_sha1("HEAD", sha1))
165                 return;
166         obj = parse_object(sha1);
167         if (!obj)
168                 return;
169         add_pending_object(revs, obj, "HEAD");
170 }
171
172 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
173 {
174         struct object *object;
175
176         object = parse_object(sha1);
177         if (!object)
178                 die("bad object %s", name);
179         object->flags |= flags;
180         return object;
181 }
182
183 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
184 {
185         unsigned long flags = object->flags;
186
187         /*
188          * Tag object? Look what it points to..
189          */
190         while (object->type == OBJ_TAG) {
191                 struct tag *tag = (struct tag *) object;
192                 if (revs->tag_objects && !(flags & UNINTERESTING))
193                         add_pending_object(revs, object, tag->tag);
194                 if (!tag->tagged)
195                         die("bad tag");
196                 object = parse_object(tag->tagged->sha1);
197                 if (!object) {
198                         if (flags & UNINTERESTING)
199                                 return NULL;
200                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
201                 }
202         }
203
204         /*
205          * Commit object? Just return it, we'll do all the complex
206          * reachability crud.
207          */
208         if (object->type == OBJ_COMMIT) {
209                 struct commit *commit = (struct commit *)object;
210                 if (parse_commit(commit) < 0)
211                         die("unable to parse commit %s", name);
212                 if (flags & UNINTERESTING) {
213                         commit->object.flags |= UNINTERESTING;
214                         mark_parents_uninteresting(commit);
215                         revs->limited = 1;
216                 }
217                 if (revs->show_source && !commit->util)
218                         commit->util = (void *) name;
219                 return commit;
220         }
221
222         /*
223          * Tree object? Either mark it uninteresting, or add it
224          * to the list of objects to look at later..
225          */
226         if (object->type == OBJ_TREE) {
227                 struct tree *tree = (struct tree *)object;
228                 if (!revs->tree_objects)
229                         return NULL;
230                 if (flags & UNINTERESTING) {
231                         mark_tree_uninteresting(tree);
232                         return NULL;
233                 }
234                 add_pending_object(revs, object, "");
235                 return NULL;
236         }
237
238         /*
239          * Blob object? You know the drill by now..
240          */
241         if (object->type == OBJ_BLOB) {
242                 struct blob *blob = (struct blob *)object;
243                 if (!revs->blob_objects)
244                         return NULL;
245                 if (flags & UNINTERESTING) {
246                         mark_blob_uninteresting(blob);
247                         return NULL;
248                 }
249                 add_pending_object(revs, object, "");
250                 return NULL;
251         }
252         die("%s is unknown object", name);
253 }
254
255 static int everybody_uninteresting(struct commit_list *orig)
256 {
257         struct commit_list *list = orig;
258         while (list) {
259                 struct commit *commit = list->item;
260                 list = list->next;
261                 if (commit->object.flags & UNINTERESTING)
262                         continue;
263                 return 0;
264         }
265         return 1;
266 }
267
268 /*
269  * The goal is to get REV_TREE_NEW as the result only if the
270  * diff consists of all '+' (and no other changes), REV_TREE_OLD
271  * if the whole diff is removal of old data, and otherwise
272  * REV_TREE_DIFFERENT (of course if the trees are the same we
273  * want REV_TREE_SAME).
274  * That means that once we get to REV_TREE_DIFFERENT, we do not
275  * have to look any further.
276  */
277 static int tree_difference = REV_TREE_SAME;
278
279 static void file_add_remove(struct diff_options *options,
280                     int addremove, unsigned mode,
281                     const unsigned char *sha1,
282                     const char *fullpath, unsigned dirty_submodule)
283 {
284         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
285
286         tree_difference |= diff;
287         if (tree_difference == REV_TREE_DIFFERENT)
288                 DIFF_OPT_SET(options, HAS_CHANGES);
289 }
290
291 static void file_change(struct diff_options *options,
292                  unsigned old_mode, unsigned new_mode,
293                  const unsigned char *old_sha1,
294                  const unsigned char *new_sha1,
295                  const char *fullpath,
296                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
297 {
298         tree_difference = REV_TREE_DIFFERENT;
299         DIFF_OPT_SET(options, HAS_CHANGES);
300 }
301
302 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
303 {
304         struct tree *t1 = parent->tree;
305         struct tree *t2 = commit->tree;
306
307         if (!t1)
308                 return REV_TREE_NEW;
309         if (!t2)
310                 return REV_TREE_OLD;
311
312         if (revs->simplify_by_decoration) {
313                 /*
314                  * If we are simplifying by decoration, then the commit
315                  * is worth showing if it has a tag pointing at it.
316                  */
317                 if (lookup_decoration(&name_decoration, &commit->object))
318                         return REV_TREE_DIFFERENT;
319                 /*
320                  * A commit that is not pointed by a tag is uninteresting
321                  * if we are not limited by path.  This means that you will
322                  * see the usual "commits that touch the paths" plus any
323                  * tagged commit by specifying both --simplify-by-decoration
324                  * and pathspec.
325                  */
326                 if (!revs->prune_data.nr)
327                         return REV_TREE_SAME;
328         }
329
330         tree_difference = REV_TREE_SAME;
331         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
332         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
333                            &revs->pruning) < 0)
334                 return REV_TREE_DIFFERENT;
335         return tree_difference;
336 }
337
338 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
339 {
340         int retval;
341         void *tree;
342         unsigned long size;
343         struct tree_desc empty, real;
344         struct tree *t1 = commit->tree;
345
346         if (!t1)
347                 return 0;
348
349         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
350         if (!tree)
351                 return 0;
352         init_tree_desc(&real, tree, size);
353         init_tree_desc(&empty, "", 0);
354
355         tree_difference = REV_TREE_SAME;
356         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
357         retval = diff_tree(&empty, &real, "", &revs->pruning);
358         free(tree);
359
360         return retval >= 0 && (tree_difference == REV_TREE_SAME);
361 }
362
363 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
364 {
365         struct commit_list **pp, *parent;
366         int tree_changed = 0, tree_same = 0;
367
368         /*
369          * If we don't do pruning, everything is interesting
370          */
371         if (!revs->prune)
372                 return;
373
374         if (!commit->tree)
375                 return;
376
377         if (!commit->parents) {
378                 if (rev_same_tree_as_empty(revs, commit))
379                         commit->object.flags |= TREESAME;
380                 return;
381         }
382
383         /*
384          * Normal non-merge commit? If we don't want to make the
385          * history dense, we consider it always to be a change..
386          */
387         if (!revs->dense && !commit->parents->next)
388                 return;
389
390         pp = &commit->parents;
391         while ((parent = *pp) != NULL) {
392                 struct commit *p = parent->item;
393
394                 if (parse_commit(p) < 0)
395                         die("cannot simplify commit %s (because of %s)",
396                             sha1_to_hex(commit->object.sha1),
397                             sha1_to_hex(p->object.sha1));
398                 switch (rev_compare_tree(revs, p, commit)) {
399                 case REV_TREE_SAME:
400                         tree_same = 1;
401                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
402                                 /* Even if a merge with an uninteresting
403                                  * side branch brought the entire change
404                                  * we are interested in, we do not want
405                                  * to lose the other branches of this
406                                  * merge, so we just keep going.
407                                  */
408                                 pp = &parent->next;
409                                 continue;
410                         }
411                         parent->next = NULL;
412                         commit->parents = parent;
413                         commit->object.flags |= TREESAME;
414                         return;
415
416                 case REV_TREE_NEW:
417                         if (revs->remove_empty_trees &&
418                             rev_same_tree_as_empty(revs, p)) {
419                                 /* We are adding all the specified
420                                  * paths from this parent, so the
421                                  * history beyond this parent is not
422                                  * interesting.  Remove its parents
423                                  * (they are grandparents for us).
424                                  * IOW, we pretend this parent is a
425                                  * "root" commit.
426                                  */
427                                 if (parse_commit(p) < 0)
428                                         die("cannot simplify commit %s (invalid %s)",
429                                             sha1_to_hex(commit->object.sha1),
430                                             sha1_to_hex(p->object.sha1));
431                                 p->parents = NULL;
432                         }
433                 /* fallthrough */
434                 case REV_TREE_OLD:
435                 case REV_TREE_DIFFERENT:
436                         tree_changed = 1;
437                         pp = &parent->next;
438                         continue;
439                 }
440                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
441         }
442         if (tree_changed && !tree_same)
443                 return;
444         commit->object.flags |= TREESAME;
445 }
446
447 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
448                     struct commit_list *cached_base, struct commit_list **cache)
449 {
450         struct commit_list *new_entry;
451
452         if (cached_base && p->date < cached_base->item->date)
453                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
454         else
455                 new_entry = commit_list_insert_by_date(p, head);
456
457         if (cache && (!*cache || p->date < (*cache)->item->date))
458                 *cache = new_entry;
459 }
460
461 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
462                     struct commit_list **list, struct commit_list **cache_ptr)
463 {
464         struct commit_list *parent = commit->parents;
465         unsigned left_flag;
466         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
467
468         if (commit->object.flags & ADDED)
469                 return 0;
470         commit->object.flags |= ADDED;
471
472         /*
473          * If the commit is uninteresting, don't try to
474          * prune parents - we want the maximal uninteresting
475          * set.
476          *
477          * Normally we haven't parsed the parent
478          * yet, so we won't have a parent of a parent
479          * here. However, it may turn out that we've
480          * reached this commit some other way (where it
481          * wasn't uninteresting), in which case we need
482          * to mark its parents recursively too..
483          */
484         if (commit->object.flags & UNINTERESTING) {
485                 while (parent) {
486                         struct commit *p = parent->item;
487                         parent = parent->next;
488                         if (p)
489                                 p->object.flags |= UNINTERESTING;
490                         if (parse_commit(p) < 0)
491                                 continue;
492                         if (p->parents)
493                                 mark_parents_uninteresting(p);
494                         if (p->object.flags & SEEN)
495                                 continue;
496                         p->object.flags |= SEEN;
497                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
498                 }
499                 return 0;
500         }
501
502         /*
503          * Ok, the commit wasn't uninteresting. Try to
504          * simplify the commit history and find the parent
505          * that has no differences in the path set if one exists.
506          */
507         try_to_simplify_commit(revs, commit);
508
509         if (revs->no_walk)
510                 return 0;
511
512         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
513
514         for (parent = commit->parents; parent; parent = parent->next) {
515                 struct commit *p = parent->item;
516
517                 if (parse_commit(p) < 0)
518                         return -1;
519                 if (revs->show_source && !p->util)
520                         p->util = commit->util;
521                 p->object.flags |= left_flag;
522                 if (!(p->object.flags & SEEN)) {
523                         p->object.flags |= SEEN;
524                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
525                 }
526                 if (revs->first_parent_only)
527                         break;
528         }
529         return 0;
530 }
531
532 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
533 {
534         struct commit_list *p;
535         int left_count = 0, right_count = 0;
536         int left_first;
537         struct patch_ids ids;
538         unsigned cherry_flag;
539
540         /* First count the commits on the left and on the right */
541         for (p = list; p; p = p->next) {
542                 struct commit *commit = p->item;
543                 unsigned flags = commit->object.flags;
544                 if (flags & BOUNDARY)
545                         ;
546                 else if (flags & SYMMETRIC_LEFT)
547                         left_count++;
548                 else
549                         right_count++;
550         }
551
552         if (!left_count || !right_count)
553                 return;
554
555         left_first = left_count < right_count;
556         init_patch_ids(&ids);
557         ids.diffopts.pathspec = revs->diffopt.pathspec;
558
559         /* Compute patch-ids for one side */
560         for (p = list; p; p = p->next) {
561                 struct commit *commit = p->item;
562                 unsigned flags = commit->object.flags;
563
564                 if (flags & BOUNDARY)
565                         continue;
566                 /*
567                  * If we have fewer left, left_first is set and we omit
568                  * commits on the right branch in this loop.  If we have
569                  * fewer right, we skip the left ones.
570                  */
571                 if (left_first != !!(flags & SYMMETRIC_LEFT))
572                         continue;
573                 commit->util = add_commit_patch_id(commit, &ids);
574         }
575
576         /* either cherry_mark or cherry_pick are true */
577         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
578
579         /* Check the other side */
580         for (p = list; p; p = p->next) {
581                 struct commit *commit = p->item;
582                 struct patch_id *id;
583                 unsigned flags = commit->object.flags;
584
585                 if (flags & BOUNDARY)
586                         continue;
587                 /*
588                  * If we have fewer left, left_first is set and we omit
589                  * commits on the left branch in this loop.
590                  */
591                 if (left_first == !!(flags & SYMMETRIC_LEFT))
592                         continue;
593
594                 /*
595                  * Have we seen the same patch id?
596                  */
597                 id = has_commit_patch_id(commit, &ids);
598                 if (!id)
599                         continue;
600                 id->seen = 1;
601                 commit->object.flags |= cherry_flag;
602         }
603
604         /* Now check the original side for seen ones */
605         for (p = list; p; p = p->next) {
606                 struct commit *commit = p->item;
607                 struct patch_id *ent;
608
609                 ent = commit->util;
610                 if (!ent)
611                         continue;
612                 if (ent->seen)
613                         commit->object.flags |= cherry_flag;
614                 commit->util = NULL;
615         }
616
617         free_patch_ids(&ids);
618 }
619
620 /* How many extra uninteresting commits we want to see.. */
621 #define SLOP 5
622
623 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
624 {
625         /*
626          * No source list at all? We're definitely done..
627          */
628         if (!src)
629                 return 0;
630
631         /*
632          * Does the destination list contain entries with a date
633          * before the source list? Definitely _not_ done.
634          */
635         if (date < src->item->date)
636                 return SLOP;
637
638         /*
639          * Does the source list still have interesting commits in
640          * it? Definitely not done..
641          */
642         if (!everybody_uninteresting(src))
643                 return SLOP;
644
645         /* Ok, we're closing in.. */
646         return slop-1;
647 }
648
649 /*
650  * "rev-list --ancestry-path A..B" computes commits that are ancestors
651  * of B but not ancestors of A but further limits the result to those
652  * that are descendants of A.  This takes the list of bottom commits and
653  * the result of "A..B" without --ancestry-path, and limits the latter
654  * further to the ones that can reach one of the commits in "bottom".
655  */
656 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
657 {
658         struct commit_list *p;
659         struct commit_list *rlist = NULL;
660         int made_progress;
661
662         /*
663          * Reverse the list so that it will be likely that we would
664          * process parents before children.
665          */
666         for (p = list; p; p = p->next)
667                 commit_list_insert(p->item, &rlist);
668
669         for (p = bottom; p; p = p->next)
670                 p->item->object.flags |= TMP_MARK;
671
672         /*
673          * Mark the ones that can reach bottom commits in "list",
674          * in a bottom-up fashion.
675          */
676         do {
677                 made_progress = 0;
678                 for (p = rlist; p; p = p->next) {
679                         struct commit *c = p->item;
680                         struct commit_list *parents;
681                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
682                                 continue;
683                         for (parents = c->parents;
684                              parents;
685                              parents = parents->next) {
686                                 if (!(parents->item->object.flags & TMP_MARK))
687                                         continue;
688                                 c->object.flags |= TMP_MARK;
689                                 made_progress = 1;
690                                 break;
691                         }
692                 }
693         } while (made_progress);
694
695         /*
696          * NEEDSWORK: decide if we want to remove parents that are
697          * not marked with TMP_MARK from commit->parents for commits
698          * in the resulting list.  We may not want to do that, though.
699          */
700
701         /*
702          * The ones that are not marked with TMP_MARK are uninteresting
703          */
704         for (p = list; p; p = p->next) {
705                 struct commit *c = p->item;
706                 if (c->object.flags & TMP_MARK)
707                         continue;
708                 c->object.flags |= UNINTERESTING;
709         }
710
711         /* We are done with the TMP_MARK */
712         for (p = list; p; p = p->next)
713                 p->item->object.flags &= ~TMP_MARK;
714         for (p = bottom; p; p = p->next)
715                 p->item->object.flags &= ~TMP_MARK;
716         free_commit_list(rlist);
717 }
718
719 /*
720  * Before walking the history, keep the set of "negative" refs the
721  * caller has asked to exclude.
722  *
723  * This is used to compute "rev-list --ancestry-path A..B", as we need
724  * to filter the result of "A..B" further to the ones that can actually
725  * reach A.
726  */
727 static struct commit_list *collect_bottom_commits(struct commit_list *list)
728 {
729         struct commit_list *elem, *bottom = NULL;
730         for (elem = list; elem; elem = elem->next)
731                 if (elem->item->object.flags & UNINTERESTING)
732                         commit_list_insert(elem->item, &bottom);
733         return bottom;
734 }
735
736 /* Assumes either left_only or right_only is set */
737 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
738 {
739         struct commit_list *p;
740
741         for (p = list; p; p = p->next) {
742                 struct commit *commit = p->item;
743
744                 if (revs->right_only) {
745                         if (commit->object.flags & SYMMETRIC_LEFT)
746                                 commit->object.flags |= SHOWN;
747                 } else  /* revs->left_only is set */
748                         if (!(commit->object.flags & SYMMETRIC_LEFT))
749                                 commit->object.flags |= SHOWN;
750         }
751 }
752
753 static int limit_list(struct rev_info *revs)
754 {
755         int slop = SLOP;
756         unsigned long date = ~0ul;
757         struct commit_list *list = revs->commits;
758         struct commit_list *newlist = NULL;
759         struct commit_list **p = &newlist;
760         struct commit_list *bottom = NULL;
761
762         if (revs->ancestry_path) {
763                 bottom = collect_bottom_commits(list);
764                 if (!bottom)
765                         die("--ancestry-path given but there are no bottom commits");
766         }
767
768         while (list) {
769                 struct commit_list *entry = list;
770                 struct commit *commit = list->item;
771                 struct object *obj = &commit->object;
772                 show_early_output_fn_t show;
773
774                 list = list->next;
775                 free(entry);
776
777                 if (revs->max_age != -1 && (commit->date < revs->max_age))
778                         obj->flags |= UNINTERESTING;
779                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
780                         return -1;
781                 if (obj->flags & UNINTERESTING) {
782                         mark_parents_uninteresting(commit);
783                         if (revs->show_all)
784                                 p = &commit_list_insert(commit, p)->next;
785                         slop = still_interesting(list, date, slop);
786                         if (slop)
787                                 continue;
788                         /* If showing all, add the whole pending list to the end */
789                         if (revs->show_all)
790                                 *p = list;
791                         break;
792                 }
793                 if (revs->min_age != -1 && (commit->date > revs->min_age))
794                         continue;
795                 date = commit->date;
796                 p = &commit_list_insert(commit, p)->next;
797
798                 show = show_early_output;
799                 if (!show)
800                         continue;
801
802                 show(revs, newlist);
803                 show_early_output = NULL;
804         }
805         if (revs->cherry_pick || revs->cherry_mark)
806                 cherry_pick_list(newlist, revs);
807
808         if (revs->left_only || revs->right_only)
809                 limit_left_right(newlist, revs);
810
811         if (bottom) {
812                 limit_to_ancestry(bottom, newlist);
813                 free_commit_list(bottom);
814         }
815
816         revs->commits = newlist;
817         return 0;
818 }
819
820 struct all_refs_cb {
821         int all_flags;
822         int warned_bad_reflog;
823         struct rev_info *all_revs;
824         const char *name_for_errormsg;
825 };
826
827 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
828 {
829         struct all_refs_cb *cb = cb_data;
830         struct object *object = get_reference(cb->all_revs, path, sha1,
831                                               cb->all_flags);
832         add_pending_object(cb->all_revs, object, path);
833         return 0;
834 }
835
836 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
837         unsigned flags)
838 {
839         cb->all_revs = revs;
840         cb->all_flags = flags;
841 }
842
843 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
844                 int (*for_each)(const char *, each_ref_fn, void *))
845 {
846         struct all_refs_cb cb;
847         init_all_refs_cb(&cb, revs, flags);
848         for_each(submodule, handle_one_ref, &cb);
849 }
850
851 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
852 {
853         struct all_refs_cb *cb = cb_data;
854         if (!is_null_sha1(sha1)) {
855                 struct object *o = parse_object(sha1);
856                 if (o) {
857                         o->flags |= cb->all_flags;
858                         add_pending_object(cb->all_revs, o, "");
859                 }
860                 else if (!cb->warned_bad_reflog) {
861                         warning("reflog of '%s' references pruned commits",
862                                 cb->name_for_errormsg);
863                         cb->warned_bad_reflog = 1;
864                 }
865         }
866 }
867
868 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
869                 const char *email, unsigned long timestamp, int tz,
870                 const char *message, void *cb_data)
871 {
872         handle_one_reflog_commit(osha1, cb_data);
873         handle_one_reflog_commit(nsha1, cb_data);
874         return 0;
875 }
876
877 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
878 {
879         struct all_refs_cb *cb = cb_data;
880         cb->warned_bad_reflog = 0;
881         cb->name_for_errormsg = path;
882         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
883         return 0;
884 }
885
886 static void handle_reflog(struct rev_info *revs, unsigned flags)
887 {
888         struct all_refs_cb cb;
889         cb.all_revs = revs;
890         cb.all_flags = flags;
891         for_each_reflog(handle_one_reflog, &cb);
892 }
893
894 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
895 {
896         unsigned char sha1[20];
897         struct object *it;
898         struct commit *commit;
899         struct commit_list *parents;
900
901         if (*arg == '^') {
902                 flags ^= UNINTERESTING;
903                 arg++;
904         }
905         if (get_sha1(arg, sha1))
906                 return 0;
907         while (1) {
908                 it = get_reference(revs, arg, sha1, 0);
909                 if (it->type != OBJ_TAG)
910                         break;
911                 if (!((struct tag*)it)->tagged)
912                         return 0;
913                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
914         }
915         if (it->type != OBJ_COMMIT)
916                 return 0;
917         commit = (struct commit *)it;
918         for (parents = commit->parents; parents; parents = parents->next) {
919                 it = &parents->item->object;
920                 it->flags |= flags;
921                 add_pending_object(revs, it, arg);
922         }
923         return 1;
924 }
925
926 void init_revisions(struct rev_info *revs, const char *prefix)
927 {
928         memset(revs, 0, sizeof(*revs));
929
930         revs->abbrev = DEFAULT_ABBREV;
931         revs->ignore_merges = 1;
932         revs->simplify_history = 1;
933         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
934         DIFF_OPT_SET(&revs->pruning, QUICK);
935         revs->pruning.add_remove = file_add_remove;
936         revs->pruning.change = file_change;
937         revs->lifo = 1;
938         revs->dense = 1;
939         revs->prefix = prefix;
940         revs->max_age = -1;
941         revs->min_age = -1;
942         revs->skip_count = -1;
943         revs->max_count = -1;
944         revs->max_parents = -1;
945
946         revs->commit_format = CMIT_FMT_DEFAULT;
947
948         revs->grep_filter.status_only = 1;
949         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
950         revs->grep_filter.header_tail = &(revs->grep_filter.header_list);
951         revs->grep_filter.regflags = REG_NEWLINE;
952
953         diff_setup(&revs->diffopt);
954         if (prefix && !revs->diffopt.prefix) {
955                 revs->diffopt.prefix = prefix;
956                 revs->diffopt.prefix_length = strlen(prefix);
957         }
958
959         revs->notes_opt.use_default_notes = -1;
960 }
961
962 static void add_pending_commit_list(struct rev_info *revs,
963                                     struct commit_list *commit_list,
964                                     unsigned int flags)
965 {
966         while (commit_list) {
967                 struct object *object = &commit_list->item->object;
968                 object->flags |= flags;
969                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
970                 commit_list = commit_list->next;
971         }
972 }
973
974 static void prepare_show_merge(struct rev_info *revs)
975 {
976         struct commit_list *bases;
977         struct commit *head, *other;
978         unsigned char sha1[20];
979         const char **prune = NULL;
980         int i, prune_num = 1; /* counting terminating NULL */
981
982         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
983                 die("--merge without HEAD?");
984         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
985                 die("--merge without MERGE_HEAD?");
986         add_pending_object(revs, &head->object, "HEAD");
987         add_pending_object(revs, &other->object, "MERGE_HEAD");
988         bases = get_merge_bases(head, other, 1);
989         add_pending_commit_list(revs, bases, UNINTERESTING);
990         free_commit_list(bases);
991         head->object.flags |= SYMMETRIC_LEFT;
992
993         if (!active_nr)
994                 read_cache();
995         for (i = 0; i < active_nr; i++) {
996                 struct cache_entry *ce = active_cache[i];
997                 if (!ce_stage(ce))
998                         continue;
999                 if (ce_path_match(ce, &revs->prune_data)) {
1000                         prune_num++;
1001                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
1002                         prune[prune_num-2] = ce->name;
1003                         prune[prune_num-1] = NULL;
1004                 }
1005                 while ((i+1 < active_nr) &&
1006                        ce_same_name(ce, active_cache[i+1]))
1007                         i++;
1008         }
1009         free_pathspec(&revs->prune_data);
1010         init_pathspec(&revs->prune_data, prune);
1011         revs->limited = 1;
1012 }
1013
1014 int handle_revision_arg(const char *arg, struct rev_info *revs,
1015                         int flags,
1016                         int cant_be_filename)
1017 {
1018         unsigned mode;
1019         char *dotdot;
1020         struct object *object;
1021         unsigned char sha1[20];
1022         int local_flags;
1023
1024         dotdot = strstr(arg, "..");
1025         if (dotdot) {
1026                 unsigned char from_sha1[20];
1027                 const char *next = dotdot + 2;
1028                 const char *this = arg;
1029                 int symmetric = *next == '.';
1030                 unsigned int flags_exclude = flags ^ UNINTERESTING;
1031
1032                 *dotdot = 0;
1033                 next += symmetric;
1034
1035                 if (!*next)
1036                         next = "HEAD";
1037                 if (dotdot == arg)
1038                         this = "HEAD";
1039                 if (!get_sha1(this, from_sha1) &&
1040                     !get_sha1(next, sha1)) {
1041                         struct commit *a, *b;
1042                         struct commit_list *exclude;
1043
1044                         a = lookup_commit_reference(from_sha1);
1045                         b = lookup_commit_reference(sha1);
1046                         if (!a || !b) {
1047                                 die(symmetric ?
1048                                     "Invalid symmetric difference expression %s...%s" :
1049                                     "Invalid revision range %s..%s",
1050                                     arg, next);
1051                         }
1052
1053                         if (!cant_be_filename) {
1054                                 *dotdot = '.';
1055                                 verify_non_filename(revs->prefix, arg);
1056                         }
1057
1058                         if (symmetric) {
1059                                 exclude = get_merge_bases(a, b, 1);
1060                                 add_pending_commit_list(revs, exclude,
1061                                                         flags_exclude);
1062                                 free_commit_list(exclude);
1063                                 a->object.flags |= flags | SYMMETRIC_LEFT;
1064                         } else
1065                                 a->object.flags |= flags_exclude;
1066                         b->object.flags |= flags;
1067                         add_pending_object(revs, &a->object, this);
1068                         add_pending_object(revs, &b->object, next);
1069                         return 0;
1070                 }
1071                 *dotdot = '.';
1072         }
1073         dotdot = strstr(arg, "^@");
1074         if (dotdot && !dotdot[2]) {
1075                 *dotdot = 0;
1076                 if (add_parents_only(revs, arg, flags))
1077                         return 0;
1078                 *dotdot = '^';
1079         }
1080         dotdot = strstr(arg, "^!");
1081         if (dotdot && !dotdot[2]) {
1082                 *dotdot = 0;
1083                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
1084                         *dotdot = '^';
1085         }
1086
1087         local_flags = 0;
1088         if (*arg == '^') {
1089                 local_flags = UNINTERESTING;
1090                 arg++;
1091         }
1092         if (get_sha1_with_mode(arg, sha1, &mode))
1093                 return -1;
1094         if (!cant_be_filename)
1095                 verify_non_filename(revs->prefix, arg);
1096         object = get_reference(revs, arg, sha1, flags ^ local_flags);
1097         add_pending_object_with_mode(revs, object, arg, mode);
1098         return 0;
1099 }
1100
1101 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb, const char ***prune_data)
1102 {
1103         const char **prune = *prune_data;
1104         int prune_nr;
1105         int prune_alloc;
1106
1107         /* count existing ones */
1108         if (!prune)
1109                 prune_nr = 0;
1110         else
1111                 for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1112                         ;
1113         prune_alloc = prune_nr; /* not really, but we do not know */
1114
1115         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
1116                 int len = sb->len;
1117                 if (len && sb->buf[len - 1] == '\n')
1118                         sb->buf[--len] = '\0';
1119                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1120                 prune[prune_nr++] = xstrdup(sb->buf);
1121         }
1122         if (prune) {
1123                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1124                 prune[prune_nr] = NULL;
1125         }
1126         *prune_data = prune;
1127 }
1128
1129 static void read_revisions_from_stdin(struct rev_info *revs, const char ***prune)
1130 {
1131         struct strbuf sb;
1132         int seen_dashdash = 0;
1133
1134         strbuf_init(&sb, 1000);
1135         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1136                 int len = sb.len;
1137                 if (len && sb.buf[len - 1] == '\n')
1138                         sb.buf[--len] = '\0';
1139                 if (!len)
1140                         break;
1141                 if (sb.buf[0] == '-') {
1142                         if (len == 2 && sb.buf[1] == '-') {
1143                                 seen_dashdash = 1;
1144                                 break;
1145                         }
1146                         die("options not supported in --stdin mode");
1147                 }
1148                 if (handle_revision_arg(sb.buf, revs, 0, 1))
1149                         die("bad revision '%s'", sb.buf);
1150         }
1151         if (seen_dashdash)
1152                 read_pathspec_from_stdin(revs, &sb, prune);
1153         strbuf_release(&sb);
1154 }
1155
1156 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1157 {
1158         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1159 }
1160
1161 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1162 {
1163         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1164 }
1165
1166 static void add_message_grep(struct rev_info *revs, const char *pattern)
1167 {
1168         add_grep(revs, pattern, GREP_PATTERN_BODY);
1169 }
1170
1171 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1172                                int *unkc, const char **unkv)
1173 {
1174         const char *arg = argv[0];
1175         const char *optarg;
1176         int argcount;
1177
1178         /* pseudo revision arguments */
1179         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1180             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1181             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1182             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1183             !strcmp(arg, "--bisect") || !prefixcmp(arg, "--glob=") ||
1184             !prefixcmp(arg, "--branches=") || !prefixcmp(arg, "--tags=") ||
1185             !prefixcmp(arg, "--remotes="))
1186         {
1187                 unkv[(*unkc)++] = arg;
1188                 return 1;
1189         }
1190
1191         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1192                 revs->max_count = atoi(optarg);
1193                 revs->no_walk = 0;
1194                 return argcount;
1195         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1196                 revs->skip_count = atoi(optarg);
1197                 return argcount;
1198         } else if ((*arg == '-') && isdigit(arg[1])) {
1199         /* accept -<digit>, like traditional "head" */
1200                 revs->max_count = atoi(arg + 1);
1201                 revs->no_walk = 0;
1202         } else if (!strcmp(arg, "-n")) {
1203                 if (argc <= 1)
1204                         return error("-n requires an argument");
1205                 revs->max_count = atoi(argv[1]);
1206                 revs->no_walk = 0;
1207                 return 2;
1208         } else if (!prefixcmp(arg, "-n")) {
1209                 revs->max_count = atoi(arg + 2);
1210                 revs->no_walk = 0;
1211         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1212                 revs->max_age = atoi(optarg);
1213                 return argcount;
1214         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1215                 revs->max_age = approxidate(optarg);
1216                 return argcount;
1217         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1218                 revs->max_age = approxidate(optarg);
1219                 return argcount;
1220         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1221                 revs->min_age = atoi(optarg);
1222                 return argcount;
1223         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1224                 revs->min_age = approxidate(optarg);
1225                 return argcount;
1226         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1227                 revs->min_age = approxidate(optarg);
1228                 return argcount;
1229         } else if (!strcmp(arg, "--first-parent")) {
1230                 revs->first_parent_only = 1;
1231         } else if (!strcmp(arg, "--ancestry-path")) {
1232                 revs->ancestry_path = 1;
1233                 revs->simplify_history = 0;
1234                 revs->limited = 1;
1235         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1236                 init_reflog_walk(&revs->reflog_info);
1237         } else if (!strcmp(arg, "--default")) {
1238                 if (argc <= 1)
1239                         return error("bad --default argument");
1240                 revs->def = argv[1];
1241                 return 2;
1242         } else if (!strcmp(arg, "--merge")) {
1243                 revs->show_merge = 1;
1244         } else if (!strcmp(arg, "--topo-order")) {
1245                 revs->lifo = 1;
1246                 revs->topo_order = 1;
1247         } else if (!strcmp(arg, "--simplify-merges")) {
1248                 revs->simplify_merges = 1;
1249                 revs->rewrite_parents = 1;
1250                 revs->simplify_history = 0;
1251                 revs->limited = 1;
1252         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1253                 revs->simplify_merges = 1;
1254                 revs->rewrite_parents = 1;
1255                 revs->simplify_history = 0;
1256                 revs->simplify_by_decoration = 1;
1257                 revs->limited = 1;
1258                 revs->prune = 1;
1259                 load_ref_decorations(DECORATE_SHORT_REFS);
1260         } else if (!strcmp(arg, "--date-order")) {
1261                 revs->lifo = 0;
1262                 revs->topo_order = 1;
1263         } else if (!prefixcmp(arg, "--early-output")) {
1264                 int count = 100;
1265                 switch (arg[14]) {
1266                 case '=':
1267                         count = atoi(arg+15);
1268                         /* Fallthrough */
1269                 case 0:
1270                         revs->topo_order = 1;
1271                        revs->early_output = count;
1272                 }
1273         } else if (!strcmp(arg, "--parents")) {
1274                 revs->rewrite_parents = 1;
1275                 revs->print_parents = 1;
1276         } else if (!strcmp(arg, "--dense")) {
1277                 revs->dense = 1;
1278         } else if (!strcmp(arg, "--sparse")) {
1279                 revs->dense = 0;
1280         } else if (!strcmp(arg, "--show-all")) {
1281                 revs->show_all = 1;
1282         } else if (!strcmp(arg, "--remove-empty")) {
1283                 revs->remove_empty_trees = 1;
1284         } else if (!strcmp(arg, "--merges")) {
1285                 revs->min_parents = 2;
1286         } else if (!strcmp(arg, "--no-merges")) {
1287                 revs->max_parents = 1;
1288         } else if (!prefixcmp(arg, "--min-parents=")) {
1289                 revs->min_parents = atoi(arg+14);
1290         } else if (!prefixcmp(arg, "--no-min-parents")) {
1291                 revs->min_parents = 0;
1292         } else if (!prefixcmp(arg, "--max-parents=")) {
1293                 revs->max_parents = atoi(arg+14);
1294         } else if (!prefixcmp(arg, "--no-max-parents")) {
1295                 revs->max_parents = -1;
1296         } else if (!strcmp(arg, "--boundary")) {
1297                 revs->boundary = 1;
1298         } else if (!strcmp(arg, "--left-right")) {
1299                 revs->left_right = 1;
1300         } else if (!strcmp(arg, "--left-only")) {
1301                 if (revs->right_only)
1302                         die("--left-only is incompatible with --right-only"
1303                             " or --cherry");
1304                 revs->left_only = 1;
1305         } else if (!strcmp(arg, "--right-only")) {
1306                 if (revs->left_only)
1307                         die("--right-only is incompatible with --left-only");
1308                 revs->right_only = 1;
1309         } else if (!strcmp(arg, "--cherry")) {
1310                 if (revs->left_only)
1311                         die("--cherry is incompatible with --left-only");
1312                 revs->cherry_mark = 1;
1313                 revs->right_only = 1;
1314                 revs->max_parents = 1;
1315                 revs->limited = 1;
1316         } else if (!strcmp(arg, "--count")) {
1317                 revs->count = 1;
1318         } else if (!strcmp(arg, "--cherry-mark")) {
1319                 if (revs->cherry_pick)
1320                         die("--cherry-mark is incompatible with --cherry-pick");
1321                 revs->cherry_mark = 1;
1322                 revs->limited = 1; /* needs limit_list() */
1323         } else if (!strcmp(arg, "--cherry-pick")) {
1324                 if (revs->cherry_mark)
1325                         die("--cherry-pick is incompatible with --cherry-mark");
1326                 revs->cherry_pick = 1;
1327                 revs->limited = 1;
1328         } else if (!strcmp(arg, "--objects")) {
1329                 revs->tag_objects = 1;
1330                 revs->tree_objects = 1;
1331                 revs->blob_objects = 1;
1332         } else if (!strcmp(arg, "--objects-edge")) {
1333                 revs->tag_objects = 1;
1334                 revs->tree_objects = 1;
1335                 revs->blob_objects = 1;
1336                 revs->edge_hint = 1;
1337         } else if (!strcmp(arg, "--unpacked")) {
1338                 revs->unpacked = 1;
1339         } else if (!prefixcmp(arg, "--unpacked=")) {
1340                 die("--unpacked=<packfile> no longer supported.");
1341         } else if (!strcmp(arg, "-r")) {
1342                 revs->diff = 1;
1343                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1344         } else if (!strcmp(arg, "-t")) {
1345                 revs->diff = 1;
1346                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1347                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1348         } else if (!strcmp(arg, "-m")) {
1349                 revs->ignore_merges = 0;
1350         } else if (!strcmp(arg, "-c")) {
1351                 revs->diff = 1;
1352                 revs->dense_combined_merges = 0;
1353                 revs->combine_merges = 1;
1354         } else if (!strcmp(arg, "--cc")) {
1355                 revs->diff = 1;
1356                 revs->dense_combined_merges = 1;
1357                 revs->combine_merges = 1;
1358         } else if (!strcmp(arg, "-v")) {
1359                 revs->verbose_header = 1;
1360         } else if (!strcmp(arg, "--pretty")) {
1361                 revs->verbose_header = 1;
1362                 revs->pretty_given = 1;
1363                 get_commit_format(arg+8, revs);
1364         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1365                 /*
1366                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1367                  * not allowed, since the argument is optional.
1368                  */
1369                 revs->verbose_header = 1;
1370                 revs->pretty_given = 1;
1371                 get_commit_format(arg+9, revs);
1372         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
1373                 revs->show_notes = 1;
1374                 revs->show_notes_given = 1;
1375                 revs->notes_opt.use_default_notes = 1;
1376         } else if (!prefixcmp(arg, "--show-notes=") ||
1377                    !prefixcmp(arg, "--notes=")) {
1378                 struct strbuf buf = STRBUF_INIT;
1379                 revs->show_notes = 1;
1380                 revs->show_notes_given = 1;
1381                 if (!prefixcmp(arg, "--show-notes")) {
1382                         if (revs->notes_opt.use_default_notes < 0)
1383                                 revs->notes_opt.use_default_notes = 1;
1384                         strbuf_addstr(&buf, arg+13);
1385                 }
1386                 else
1387                         strbuf_addstr(&buf, arg+8);
1388                 expand_notes_ref(&buf);
1389                 string_list_append(&revs->notes_opt.extra_notes_refs,
1390                                    strbuf_detach(&buf, NULL));
1391         } else if (!strcmp(arg, "--no-notes")) {
1392                 revs->show_notes = 0;
1393                 revs->show_notes_given = 1;
1394                 revs->notes_opt.use_default_notes = -1;
1395                 /* we have been strdup'ing ourselves, so trick
1396                  * string_list into free()ing strings */
1397                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
1398                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
1399                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
1400         } else if (!strcmp(arg, "--standard-notes")) {
1401                 revs->show_notes_given = 1;
1402                 revs->notes_opt.use_default_notes = 1;
1403         } else if (!strcmp(arg, "--no-standard-notes")) {
1404                 revs->notes_opt.use_default_notes = 0;
1405         } else if (!strcmp(arg, "--oneline")) {
1406                 revs->verbose_header = 1;
1407                 get_commit_format("oneline", revs);
1408                 revs->pretty_given = 1;
1409                 revs->abbrev_commit = 1;
1410         } else if (!strcmp(arg, "--graph")) {
1411                 revs->topo_order = 1;
1412                 revs->rewrite_parents = 1;
1413                 revs->graph = graph_init(revs);
1414         } else if (!strcmp(arg, "--root")) {
1415                 revs->show_root_diff = 1;
1416         } else if (!strcmp(arg, "--no-commit-id")) {
1417                 revs->no_commit_id = 1;
1418         } else if (!strcmp(arg, "--always")) {
1419                 revs->always_show_header = 1;
1420         } else if (!strcmp(arg, "--no-abbrev")) {
1421                 revs->abbrev = 0;
1422         } else if (!strcmp(arg, "--abbrev")) {
1423                 revs->abbrev = DEFAULT_ABBREV;
1424         } else if (!prefixcmp(arg, "--abbrev=")) {
1425                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1426                 if (revs->abbrev < MINIMUM_ABBREV)
1427                         revs->abbrev = MINIMUM_ABBREV;
1428                 else if (revs->abbrev > 40)
1429                         revs->abbrev = 40;
1430         } else if (!strcmp(arg, "--abbrev-commit")) {
1431                 revs->abbrev_commit = 1;
1432         } else if (!strcmp(arg, "--full-diff")) {
1433                 revs->diff = 1;
1434                 revs->full_diff = 1;
1435         } else if (!strcmp(arg, "--full-history")) {
1436                 revs->simplify_history = 0;
1437         } else if (!strcmp(arg, "--relative-date")) {
1438                 revs->date_mode = DATE_RELATIVE;
1439                 revs->date_mode_explicit = 1;
1440         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
1441                 revs->date_mode = parse_date_format(optarg);
1442                 revs->date_mode_explicit = 1;
1443                 return argcount;
1444         } else if (!strcmp(arg, "--log-size")) {
1445                 revs->show_log_size = 1;
1446         }
1447         /*
1448          * Grepping the commit log
1449          */
1450         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
1451                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
1452                 return argcount;
1453         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
1454                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
1455                 return argcount;
1456         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
1457                 add_message_grep(revs, optarg);
1458                 return argcount;
1459         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1460                 revs->grep_filter.regflags |= REG_EXTENDED;
1461         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1462                 revs->grep_filter.regflags |= REG_ICASE;
1463         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1464                 revs->grep_filter.fixed = 1;
1465         } else if (!strcmp(arg, "--all-match")) {
1466                 revs->grep_filter.all_match = 1;
1467         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
1468                 if (strcmp(optarg, "none"))
1469                         git_log_output_encoding = xstrdup(optarg);
1470                 else
1471                         git_log_output_encoding = "";
1472                 return argcount;
1473         } else if (!strcmp(arg, "--reverse")) {
1474                 revs->reverse ^= 1;
1475         } else if (!strcmp(arg, "--children")) {
1476                 revs->children.name = "children";
1477                 revs->limited = 1;
1478         } else {
1479                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1480                 if (!opts)
1481                         unkv[(*unkc)++] = arg;
1482                 return opts;
1483         }
1484
1485         return 1;
1486 }
1487
1488 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1489                         const struct option *options,
1490                         const char * const usagestr[])
1491 {
1492         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1493                                     &ctx->cpidx, ctx->out);
1494         if (n <= 0) {
1495                 error("unknown option `%s'", ctx->argv[0]);
1496                 usage_with_options(usagestr, options);
1497         }
1498         ctx->argv += n;
1499         ctx->argc -= n;
1500 }
1501
1502 static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1503 {
1504         return for_each_ref_in_submodule(submodule, "refs/bisect/bad", fn, cb_data);
1505 }
1506
1507 static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1508 {
1509         return for_each_ref_in_submodule(submodule, "refs/bisect/good", fn, cb_data);
1510 }
1511
1512 static void append_prune_data(const char ***prune_data, const char **av)
1513 {
1514         const char **prune = *prune_data;
1515         int prune_nr;
1516         int prune_alloc;
1517
1518         if (!prune) {
1519                 *prune_data = av;
1520                 return;
1521         }
1522
1523         /* count existing ones */
1524         for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1525                 ;
1526         prune_alloc = prune_nr; /* not really, but we do not know */
1527
1528         while (*av) {
1529                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1530                 prune[prune_nr++] = *av;
1531                 av++;
1532         }
1533         if (prune) {
1534                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1535                 prune[prune_nr] = NULL;
1536         }
1537         *prune_data = prune;
1538 }
1539
1540 static int handle_revision_pseudo_opt(const char *submodule,
1541                                 struct rev_info *revs,
1542                                 int argc, const char **argv, int *flags)
1543 {
1544         const char *arg = argv[0];
1545         const char *optarg;
1546         int argcount;
1547
1548         /*
1549          * NOTE!
1550          *
1551          * Commands like "git shortlog" will not accept the options below
1552          * unless parse_revision_opt queues them (as opposed to erroring
1553          * out).
1554          *
1555          * When implementing your new pseudo-option, remember to
1556          * register it in the list at the top of handle_revision_opt.
1557          */
1558         if (!strcmp(arg, "--all")) {
1559                 handle_refs(submodule, revs, *flags, for_each_ref_submodule);
1560                 handle_refs(submodule, revs, *flags, head_ref_submodule);
1561         } else if (!strcmp(arg, "--branches")) {
1562                 handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule);
1563         } else if (!strcmp(arg, "--bisect")) {
1564                 handle_refs(submodule, revs, *flags, for_each_bad_bisect_ref);
1565                 handle_refs(submodule, revs, *flags ^ UNINTERESTING, for_each_good_bisect_ref);
1566                 revs->bisect = 1;
1567         } else if (!strcmp(arg, "--tags")) {
1568                 handle_refs(submodule, revs, *flags, for_each_tag_ref_submodule);
1569         } else if (!strcmp(arg, "--remotes")) {
1570                 handle_refs(submodule, revs, *flags, for_each_remote_ref_submodule);
1571         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
1572                 struct all_refs_cb cb;
1573                 init_all_refs_cb(&cb, revs, *flags);
1574                 for_each_glob_ref(handle_one_ref, optarg, &cb);
1575                 return argcount;
1576         } else if (!prefixcmp(arg, "--branches=")) {
1577                 struct all_refs_cb cb;
1578                 init_all_refs_cb(&cb, revs, *flags);
1579                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
1580         } else if (!prefixcmp(arg, "--tags=")) {
1581                 struct all_refs_cb cb;
1582                 init_all_refs_cb(&cb, revs, *flags);
1583                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
1584         } else if (!prefixcmp(arg, "--remotes=")) {
1585                 struct all_refs_cb cb;
1586                 init_all_refs_cb(&cb, revs, *flags);
1587                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
1588         } else if (!strcmp(arg, "--reflog")) {
1589                 handle_reflog(revs, *flags);
1590         } else if (!strcmp(arg, "--not")) {
1591                 *flags ^= UNINTERESTING;
1592         } else if (!strcmp(arg, "--no-walk")) {
1593                 revs->no_walk = 1;
1594         } else if (!strcmp(arg, "--do-walk")) {
1595                 revs->no_walk = 0;
1596         } else {
1597                 return 0;
1598         }
1599
1600         return 1;
1601 }
1602
1603 /*
1604  * Parse revision information, filling in the "rev_info" structure,
1605  * and removing the used arguments from the argument list.
1606  *
1607  * Returns the number of arguments left that weren't recognized
1608  * (which are also moved to the head of the argument list)
1609  */
1610 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
1611 {
1612         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0;
1613         const char **prune_data = NULL;
1614         const char *submodule = NULL;
1615
1616         if (opt)
1617                 submodule = opt->submodule;
1618
1619         /* First, search for "--" */
1620         seen_dashdash = 0;
1621         for (i = 1; i < argc; i++) {
1622                 const char *arg = argv[i];
1623                 if (strcmp(arg, "--"))
1624                         continue;
1625                 argv[i] = NULL;
1626                 argc = i;
1627                 if (argv[i + 1])
1628                         prune_data = argv + i + 1;
1629                 seen_dashdash = 1;
1630                 break;
1631         }
1632
1633         /* Second, deal with arguments and options */
1634         flags = 0;
1635         read_from_stdin = 0;
1636         for (left = i = 1; i < argc; i++) {
1637                 const char *arg = argv[i];
1638                 if (*arg == '-') {
1639                         int opts;
1640
1641                         opts = handle_revision_pseudo_opt(submodule,
1642                                                 revs, argc - i, argv + i,
1643                                                 &flags);
1644                         if (opts > 0) {
1645                                 i += opts - 1;
1646                                 continue;
1647                         }
1648
1649                         if (!strcmp(arg, "--stdin")) {
1650                                 if (revs->disable_stdin) {
1651                                         argv[left++] = arg;
1652                                         continue;
1653                                 }
1654                                 if (read_from_stdin++)
1655                                         die("--stdin given twice?");
1656                                 read_revisions_from_stdin(revs, &prune_data);
1657                                 continue;
1658                         }
1659
1660                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1661                         if (opts > 0) {
1662                                 i += opts - 1;
1663                                 continue;
1664                         }
1665                         if (opts < 0)
1666                                 exit(128);
1667                         continue;
1668                 }
1669
1670                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1671                         int j;
1672                         if (seen_dashdash || *arg == '^')
1673                                 die("bad revision '%s'", arg);
1674
1675                         /* If we didn't have a "--":
1676                          * (1) all filenames must exist;
1677                          * (2) all rev-args must not be interpretable
1678                          *     as a valid filename.
1679                          * but the latter we have checked in the main loop.
1680                          */
1681                         for (j = i; j < argc; j++)
1682                                 verify_filename(revs->prefix, argv[j]);
1683
1684                         append_prune_data(&prune_data, argv + i);
1685                         break;
1686                 }
1687                 else
1688                         got_rev_arg = 1;
1689         }
1690
1691         if (prune_data)
1692                 init_pathspec(&revs->prune_data, get_pathspec(revs->prefix, prune_data));
1693
1694         if (revs->def == NULL)
1695                 revs->def = opt ? opt->def : NULL;
1696         if (opt && opt->tweak)
1697                 opt->tweak(revs, opt);
1698         if (revs->show_merge)
1699                 prepare_show_merge(revs);
1700         if (revs->def && !revs->pending.nr && !got_rev_arg) {
1701                 unsigned char sha1[20];
1702                 struct object *object;
1703                 unsigned mode;
1704                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1705                         die("bad default revision '%s'", revs->def);
1706                 object = get_reference(revs, revs->def, sha1, 0);
1707                 add_pending_object_with_mode(revs, object, revs->def, mode);
1708         }
1709
1710         /* Did the user ask for any diff output? Run the diff! */
1711         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1712                 revs->diff = 1;
1713
1714         /* Pickaxe, diff-filter and rename following need diffs */
1715         if (revs->diffopt.pickaxe ||
1716             revs->diffopt.filter ||
1717             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1718                 revs->diff = 1;
1719
1720         if (revs->topo_order)
1721                 revs->limited = 1;
1722
1723         if (revs->prune_data.nr) {
1724                 diff_tree_setup_paths(revs->prune_data.raw, &revs->pruning);
1725                 /* Can't prune commits with rename following: the paths change.. */
1726                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1727                         revs->prune = 1;
1728                 if (!revs->full_diff)
1729                         diff_tree_setup_paths(revs->prune_data.raw, &revs->diffopt);
1730         }
1731         if (revs->combine_merges)
1732                 revs->ignore_merges = 0;
1733         revs->diffopt.abbrev = revs->abbrev;
1734         if (diff_setup_done(&revs->diffopt) < 0)
1735                 die("diff_setup_done failed");
1736
1737         compile_grep_patterns(&revs->grep_filter);
1738
1739         if (revs->reverse && revs->reflog_info)
1740                 die("cannot combine --reverse with --walk-reflogs");
1741         if (revs->rewrite_parents && revs->children.name)
1742                 die("cannot combine --parents and --children");
1743
1744         /*
1745          * Limitations on the graph functionality
1746          */
1747         if (revs->reverse && revs->graph)
1748                 die("cannot combine --reverse with --graph");
1749
1750         if (revs->reflog_info && revs->graph)
1751                 die("cannot combine --walk-reflogs with --graph");
1752
1753         return left;
1754 }
1755
1756 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1757 {
1758         struct commit_list *l = xcalloc(1, sizeof(*l));
1759
1760         l->item = child;
1761         l->next = add_decoration(&revs->children, &parent->object, l);
1762 }
1763
1764 static int remove_duplicate_parents(struct commit *commit)
1765 {
1766         struct commit_list **pp, *p;
1767         int surviving_parents;
1768
1769         /* Examine existing parents while marking ones we have seen... */
1770         pp = &commit->parents;
1771         while ((p = *pp) != NULL) {
1772                 struct commit *parent = p->item;
1773                 if (parent->object.flags & TMP_MARK) {
1774                         *pp = p->next;
1775                         continue;
1776                 }
1777                 parent->object.flags |= TMP_MARK;
1778                 pp = &p->next;
1779         }
1780         /* count them while clearing the temporary mark */
1781         surviving_parents = 0;
1782         for (p = commit->parents; p; p = p->next) {
1783                 p->item->object.flags &= ~TMP_MARK;
1784                 surviving_parents++;
1785         }
1786         return surviving_parents;
1787 }
1788
1789 struct merge_simplify_state {
1790         struct commit *simplified;
1791 };
1792
1793 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1794 {
1795         struct merge_simplify_state *st;
1796
1797         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1798         if (!st) {
1799                 st = xcalloc(1, sizeof(*st));
1800                 add_decoration(&revs->merge_simplification, &commit->object, st);
1801         }
1802         return st;
1803 }
1804
1805 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1806 {
1807         struct commit_list *p;
1808         struct merge_simplify_state *st, *pst;
1809         int cnt;
1810
1811         st = locate_simplify_state(revs, commit);
1812
1813         /*
1814          * Have we handled this one?
1815          */
1816         if (st->simplified)
1817                 return tail;
1818
1819         /*
1820          * An UNINTERESTING commit simplifies to itself, so does a
1821          * root commit.  We do not rewrite parents of such commit
1822          * anyway.
1823          */
1824         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1825                 st->simplified = commit;
1826                 return tail;
1827         }
1828
1829         /*
1830          * Do we know what commit all of our parents should be rewritten to?
1831          * Otherwise we are not ready to rewrite this one yet.
1832          */
1833         for (cnt = 0, p = commit->parents; p; p = p->next) {
1834                 pst = locate_simplify_state(revs, p->item);
1835                 if (!pst->simplified) {
1836                         tail = &commit_list_insert(p->item, tail)->next;
1837                         cnt++;
1838                 }
1839         }
1840         if (cnt) {
1841                 tail = &commit_list_insert(commit, tail)->next;
1842                 return tail;
1843         }
1844
1845         /*
1846          * Rewrite our list of parents.
1847          */
1848         for (p = commit->parents; p; p = p->next) {
1849                 pst = locate_simplify_state(revs, p->item);
1850                 p->item = pst->simplified;
1851         }
1852         cnt = remove_duplicate_parents(commit);
1853
1854         /*
1855          * It is possible that we are a merge and one side branch
1856          * does not have any commit that touches the given paths;
1857          * in such a case, the immediate parents will be rewritten
1858          * to different commits.
1859          *
1860          *      o----X          X: the commit we are looking at;
1861          *     /    /           o: a commit that touches the paths;
1862          * ---o----'
1863          *
1864          * Further reduce the parents by removing redundant parents.
1865          */
1866         if (1 < cnt) {
1867                 struct commit_list *h = reduce_heads(commit->parents);
1868                 cnt = commit_list_count(h);
1869                 free_commit_list(commit->parents);
1870                 commit->parents = h;
1871         }
1872
1873         /*
1874          * A commit simplifies to itself if it is a root, if it is
1875          * UNINTERESTING, if it touches the given paths, or if it is a
1876          * merge and its parents simplifies to more than one commits
1877          * (the first two cases are already handled at the beginning of
1878          * this function).
1879          *
1880          * Otherwise, it simplifies to what its sole parent simplifies to.
1881          */
1882         if (!cnt ||
1883             (commit->object.flags & UNINTERESTING) ||
1884             !(commit->object.flags & TREESAME) ||
1885             (1 < cnt))
1886                 st->simplified = commit;
1887         else {
1888                 pst = locate_simplify_state(revs, commit->parents->item);
1889                 st->simplified = pst->simplified;
1890         }
1891         return tail;
1892 }
1893
1894 static void simplify_merges(struct rev_info *revs)
1895 {
1896         struct commit_list *list;
1897         struct commit_list *yet_to_do, **tail;
1898
1899         if (!revs->topo_order)
1900                 sort_in_topological_order(&revs->commits, revs->lifo);
1901         if (!revs->prune)
1902                 return;
1903
1904         /* feed the list reversed */
1905         yet_to_do = NULL;
1906         for (list = revs->commits; list; list = list->next)
1907                 commit_list_insert(list->item, &yet_to_do);
1908         while (yet_to_do) {
1909                 list = yet_to_do;
1910                 yet_to_do = NULL;
1911                 tail = &yet_to_do;
1912                 while (list) {
1913                         struct commit *commit = list->item;
1914                         struct commit_list *next = list->next;
1915                         free(list);
1916                         list = next;
1917                         tail = simplify_one(revs, commit, tail);
1918                 }
1919         }
1920
1921         /* clean up the result, removing the simplified ones */
1922         list = revs->commits;
1923         revs->commits = NULL;
1924         tail = &revs->commits;
1925         while (list) {
1926                 struct commit *commit = list->item;
1927                 struct commit_list *next = list->next;
1928                 struct merge_simplify_state *st;
1929                 free(list);
1930                 list = next;
1931                 st = locate_simplify_state(revs, commit);
1932                 if (st->simplified == commit)
1933                         tail = &commit_list_insert(commit, tail)->next;
1934         }
1935 }
1936
1937 static void set_children(struct rev_info *revs)
1938 {
1939         struct commit_list *l;
1940         for (l = revs->commits; l; l = l->next) {
1941                 struct commit *commit = l->item;
1942                 struct commit_list *p;
1943
1944                 for (p = commit->parents; p; p = p->next)
1945                         add_child(revs, p->item, commit);
1946         }
1947 }
1948
1949 int prepare_revision_walk(struct rev_info *revs)
1950 {
1951         int nr = revs->pending.nr;
1952         struct object_array_entry *e, *list;
1953
1954         e = list = revs->pending.objects;
1955         revs->pending.nr = 0;
1956         revs->pending.alloc = 0;
1957         revs->pending.objects = NULL;
1958         while (--nr >= 0) {
1959                 struct commit *commit = handle_commit(revs, e->item, e->name);
1960                 if (commit) {
1961                         if (!(commit->object.flags & SEEN)) {
1962                                 commit->object.flags |= SEEN;
1963                                 commit_list_insert_by_date(commit, &revs->commits);
1964                         }
1965                 }
1966                 e++;
1967         }
1968         free(list);
1969
1970         if (revs->no_walk)
1971                 return 0;
1972         if (revs->limited)
1973                 if (limit_list(revs) < 0)
1974                         return -1;
1975         if (revs->topo_order)
1976                 sort_in_topological_order(&revs->commits, revs->lifo);
1977         if (revs->simplify_merges)
1978                 simplify_merges(revs);
1979         if (revs->children.name)
1980                 set_children(revs);
1981         return 0;
1982 }
1983
1984 enum rewrite_result {
1985         rewrite_one_ok,
1986         rewrite_one_noparents,
1987         rewrite_one_error
1988 };
1989
1990 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1991 {
1992         struct commit_list *cache = NULL;
1993
1994         for (;;) {
1995                 struct commit *p = *pp;
1996                 if (!revs->limited)
1997                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1998                                 return rewrite_one_error;
1999                 if (p->parents && p->parents->next)
2000                         return rewrite_one_ok;
2001                 if (p->object.flags & UNINTERESTING)
2002                         return rewrite_one_ok;
2003                 if (!(p->object.flags & TREESAME))
2004                         return rewrite_one_ok;
2005                 if (!p->parents)
2006                         return rewrite_one_noparents;
2007                 *pp = p->parents->item;
2008         }
2009 }
2010
2011 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
2012 {
2013         struct commit_list **pp = &commit->parents;
2014         while (*pp) {
2015                 struct commit_list *parent = *pp;
2016                 switch (rewrite_one(revs, &parent->item)) {
2017                 case rewrite_one_ok:
2018                         break;
2019                 case rewrite_one_noparents:
2020                         *pp = parent->next;
2021                         continue;
2022                 case rewrite_one_error:
2023                         return -1;
2024                 }
2025                 pp = &parent->next;
2026         }
2027         remove_duplicate_parents(commit);
2028         return 0;
2029 }
2030
2031 static int commit_match(struct commit *commit, struct rev_info *opt)
2032 {
2033         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
2034                 return 1;
2035         return grep_buffer(&opt->grep_filter,
2036                            NULL, /* we say nothing, not even filename */
2037                            commit->buffer, strlen(commit->buffer));
2038 }
2039
2040 static inline int want_ancestry(struct rev_info *revs)
2041 {
2042         return (revs->rewrite_parents || revs->children.name);
2043 }
2044
2045 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
2046 {
2047         if (commit->object.flags & SHOWN)
2048                 return commit_ignore;
2049         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
2050                 return commit_ignore;
2051         if (revs->show_all)
2052                 return commit_show;
2053         if (commit->object.flags & UNINTERESTING)
2054                 return commit_ignore;
2055         if (revs->min_age != -1 && (commit->date > revs->min_age))
2056                 return commit_ignore;
2057         if (revs->min_parents || (revs->max_parents >= 0)) {
2058                 int n = 0;
2059                 struct commit_list *p;
2060                 for (p = commit->parents; p; p = p->next)
2061                         n++;
2062                 if ((n < revs->min_parents) ||
2063                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
2064                         return commit_ignore;
2065         }
2066         if (!commit_match(commit, revs))
2067                 return commit_ignore;
2068         if (revs->prune && revs->dense) {
2069                 /* Commit without changes? */
2070                 if (commit->object.flags & TREESAME) {
2071                         /* drop merges unless we want parenthood */
2072                         if (!want_ancestry(revs))
2073                                 return commit_ignore;
2074                         /* non-merge - always ignore it */
2075                         if (!commit->parents || !commit->parents->next)
2076                                 return commit_ignore;
2077                 }
2078         }
2079         return commit_show;
2080 }
2081
2082 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
2083 {
2084         enum commit_action action = get_commit_action(revs, commit);
2085
2086         if (action == commit_show &&
2087             !revs->show_all &&
2088             revs->prune && revs->dense && want_ancestry(revs)) {
2089                 if (rewrite_parents(revs, commit) < 0)
2090                         return commit_error;
2091         }
2092         return action;
2093 }
2094
2095 static struct commit *get_revision_1(struct rev_info *revs)
2096 {
2097         if (!revs->commits)
2098                 return NULL;
2099
2100         do {
2101                 struct commit_list *entry = revs->commits;
2102                 struct commit *commit = entry->item;
2103
2104                 revs->commits = entry->next;
2105                 free(entry);
2106
2107                 if (revs->reflog_info) {
2108                         fake_reflog_parent(revs->reflog_info, commit);
2109                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
2110                 }
2111
2112                 /*
2113                  * If we haven't done the list limiting, we need to look at
2114                  * the parents here. We also need to do the date-based limiting
2115                  * that we'd otherwise have done in limit_list().
2116                  */
2117                 if (!revs->limited) {
2118                         if (revs->max_age != -1 &&
2119                             (commit->date < revs->max_age))
2120                                 continue;
2121                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
2122                                 die("Failed to traverse parents of commit %s",
2123                                     sha1_to_hex(commit->object.sha1));
2124                 }
2125
2126                 switch (simplify_commit(revs, commit)) {
2127                 case commit_ignore:
2128                         continue;
2129                 case commit_error:
2130                         die("Failed to simplify parents of commit %s",
2131                             sha1_to_hex(commit->object.sha1));
2132                 default:
2133                         return commit;
2134                 }
2135         } while (revs->commits);
2136         return NULL;
2137 }
2138
2139 static void gc_boundary(struct object_array *array)
2140 {
2141         unsigned nr = array->nr;
2142         unsigned alloc = array->alloc;
2143         struct object_array_entry *objects = array->objects;
2144
2145         if (alloc <= nr) {
2146                 unsigned i, j;
2147                 for (i = j = 0; i < nr; i++) {
2148                         if (objects[i].item->flags & SHOWN)
2149                                 continue;
2150                         if (i != j)
2151                                 objects[j] = objects[i];
2152                         j++;
2153                 }
2154                 for (i = j; i < nr; i++)
2155                         objects[i].item = NULL;
2156                 array->nr = j;
2157         }
2158 }
2159
2160 static void create_boundary_commit_list(struct rev_info *revs)
2161 {
2162         unsigned i;
2163         struct commit *c;
2164         struct object_array *array = &revs->boundary_commits;
2165         struct object_array_entry *objects = array->objects;
2166
2167         /*
2168          * If revs->commits is non-NULL at this point, an error occurred in
2169          * get_revision_1().  Ignore the error and continue printing the
2170          * boundary commits anyway.  (This is what the code has always
2171          * done.)
2172          */
2173         if (revs->commits) {
2174                 free_commit_list(revs->commits);
2175                 revs->commits = NULL;
2176         }
2177
2178         /*
2179          * Put all of the actual boundary commits from revs->boundary_commits
2180          * into revs->commits
2181          */
2182         for (i = 0; i < array->nr; i++) {
2183                 c = (struct commit *)(objects[i].item);
2184                 if (!c)
2185                         continue;
2186                 if (!(c->object.flags & CHILD_SHOWN))
2187                         continue;
2188                 if (c->object.flags & (SHOWN | BOUNDARY))
2189                         continue;
2190                 c->object.flags |= BOUNDARY;
2191                 commit_list_insert(c, &revs->commits);
2192         }
2193
2194         /*
2195          * If revs->topo_order is set, sort the boundary commits
2196          * in topological order
2197          */
2198         sort_in_topological_order(&revs->commits, revs->lifo);
2199 }
2200
2201 static struct commit *get_revision_internal(struct rev_info *revs)
2202 {
2203         struct commit *c = NULL;
2204         struct commit_list *l;
2205
2206         if (revs->boundary == 2) {
2207                 /*
2208                  * All of the normal commits have already been returned,
2209                  * and we are now returning boundary commits.
2210                  * create_boundary_commit_list() has populated
2211                  * revs->commits with the remaining commits to return.
2212                  */
2213                 c = pop_commit(&revs->commits);
2214                 if (c)
2215                         c->object.flags |= SHOWN;
2216                 return c;
2217         }
2218
2219         /*
2220          * Now pick up what they want to give us
2221          */
2222         c = get_revision_1(revs);
2223         if (c) {
2224                 while (0 < revs->skip_count) {
2225                         revs->skip_count--;
2226                         c = get_revision_1(revs);
2227                         if (!c)
2228                                 break;
2229                 }
2230         }
2231
2232         /*
2233          * Check the max_count.
2234          */
2235         switch (revs->max_count) {
2236         case -1:
2237                 break;
2238         case 0:
2239                 c = NULL;
2240                 break;
2241         default:
2242                 revs->max_count--;
2243         }
2244
2245         if (c)
2246                 c->object.flags |= SHOWN;
2247
2248         if (!revs->boundary) {
2249                 return c;
2250         }
2251
2252         if (!c) {
2253                 /*
2254                  * get_revision_1() runs out the commits, and
2255                  * we are done computing the boundaries.
2256                  * switch to boundary commits output mode.
2257                  */
2258                 revs->boundary = 2;
2259
2260                 /*
2261                  * Update revs->commits to contain the list of
2262                  * boundary commits.
2263                  */
2264                 create_boundary_commit_list(revs);
2265
2266                 return get_revision_internal(revs);
2267         }
2268
2269         /*
2270          * boundary commits are the commits that are parents of the
2271          * ones we got from get_revision_1() but they themselves are
2272          * not returned from get_revision_1().  Before returning
2273          * 'c', we need to mark its parents that they could be boundaries.
2274          */
2275
2276         for (l = c->parents; l; l = l->next) {
2277                 struct object *p;
2278                 p = &(l->item->object);
2279                 if (p->flags & (CHILD_SHOWN | SHOWN))
2280                         continue;
2281                 p->flags |= CHILD_SHOWN;
2282                 gc_boundary(&revs->boundary_commits);
2283                 add_object_array(p, NULL, &revs->boundary_commits);
2284         }
2285
2286         return c;
2287 }
2288
2289 struct commit *get_revision(struct rev_info *revs)
2290 {
2291         struct commit *c;
2292         struct commit_list *reversed;
2293
2294         if (revs->reverse) {
2295                 reversed = NULL;
2296                 while ((c = get_revision_internal(revs))) {
2297                         commit_list_insert(c, &reversed);
2298                 }
2299                 revs->commits = reversed;
2300                 revs->reverse = 0;
2301                 revs->reverse_output_stage = 1;
2302         }
2303
2304         if (revs->reverse_output_stage)
2305                 return pop_commit(&revs->commits);
2306
2307         c = get_revision_internal(revs);
2308         if (c && revs->graph)
2309                 graph_update(revs->graph, c);
2310         return c;
2311 }
2312
2313 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
2314 {
2315         if (commit->object.flags & BOUNDARY)
2316                 return "-";
2317         else if (commit->object.flags & UNINTERESTING)
2318                 return "^";
2319         else if (commit->object.flags & PATCHSAME)
2320                 return "=";
2321         else if (!revs || revs->left_right) {
2322                 if (commit->object.flags & SYMMETRIC_LEFT)
2323                         return "<";
2324                 else
2325                         return ">";
2326         } else if (revs->graph)
2327                 return "*";
2328         else if (revs->cherry_mark)
2329                 return "+";
2330         return "";
2331 }
2332
2333 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
2334 {
2335         char *mark = get_revision_mark(revs, commit);
2336         if (!strlen(mark))
2337                 return;
2338         fputs(mark, stdout);
2339         putchar(' ');
2340 }