revision.c: really honor --first-parent
[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 "grep.h"
10 #include "reflog-walk.h"
11 #include "patch-ids.h"
12
13 volatile show_early_output_fn_t show_early_output;
14
15 static char *path_name(struct name_path *path, const char *name)
16 {
17         struct name_path *p;
18         char *n, *m;
19         int nlen = strlen(name);
20         int len = nlen + 1;
21
22         for (p = path; p; p = p->up) {
23                 if (p->elem_len)
24                         len += p->elem_len + 1;
25         }
26         n = xmalloc(len);
27         m = n + len - (nlen + 1);
28         strcpy(m, name);
29         for (p = path; p; p = p->up) {
30                 if (p->elem_len) {
31                         m -= p->elem_len + 1;
32                         memcpy(m, p->elem, p->elem_len);
33                         m[p->elem_len] = '/';
34                 }
35         }
36         return n;
37 }
38
39 void add_object(struct object *obj,
40                 struct object_array *p,
41                 struct name_path *path,
42                 const char *name)
43 {
44         add_object_array(obj, path_name(path, name), p);
45 }
46
47 static void mark_blob_uninteresting(struct blob *blob)
48 {
49         if (!blob)
50                 return;
51         if (blob->object.flags & UNINTERESTING)
52                 return;
53         blob->object.flags |= UNINTERESTING;
54 }
55
56 void mark_tree_uninteresting(struct tree *tree)
57 {
58         struct tree_desc desc;
59         struct name_entry entry;
60         struct object *obj = &tree->object;
61
62         if (!tree)
63                 return;
64         if (obj->flags & UNINTERESTING)
65                 return;
66         obj->flags |= UNINTERESTING;
67         if (!has_sha1_file(obj->sha1))
68                 return;
69         if (parse_tree(tree) < 0)
70                 die("bad tree %s", sha1_to_hex(obj->sha1));
71
72         init_tree_desc(&desc, tree->buffer, tree->size);
73         while (tree_entry(&desc, &entry)) {
74                 switch (object_type(entry.mode)) {
75                 case OBJ_TREE:
76                         mark_tree_uninteresting(lookup_tree(entry.sha1));
77                         break;
78                 case OBJ_BLOB:
79                         mark_blob_uninteresting(lookup_blob(entry.sha1));
80                         break;
81                 default:
82                         /* Subproject commit - not in this repository */
83                         break;
84                 }
85         }
86
87         /*
88          * We don't care about the tree any more
89          * after it has been marked uninteresting.
90          */
91         free(tree->buffer);
92         tree->buffer = NULL;
93 }
94
95 void mark_parents_uninteresting(struct commit *commit)
96 {
97         struct commit_list *parents = commit->parents;
98
99         while (parents) {
100                 struct commit *commit = parents->item;
101                 if (!(commit->object.flags & UNINTERESTING)) {
102                         commit->object.flags |= UNINTERESTING;
103
104                         /*
105                          * Normally we haven't parsed the parent
106                          * yet, so we won't have a parent of a parent
107                          * here. However, it may turn out that we've
108                          * reached this commit some other way (where it
109                          * wasn't uninteresting), in which case we need
110                          * to mark its parents recursively too..
111                          */
112                         if (commit->parents)
113                                 mark_parents_uninteresting(commit);
114                 }
115
116                 /*
117                  * A missing commit is ok iff its parent is marked
118                  * uninteresting.
119                  *
120                  * We just mark such a thing parsed, so that when
121                  * it is popped next time around, we won't be trying
122                  * to parse it and get an error.
123                  */
124                 if (!has_sha1_file(commit->object.sha1))
125                         commit->object.parsed = 1;
126                 parents = parents->next;
127         }
128 }
129
130 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
131 {
132         if (revs->no_walk && (obj->flags & UNINTERESTING))
133                 die("object ranges do not make sense when not walking revisions");
134         if (revs->reflog_info && obj->type == OBJ_COMMIT &&
135                         add_reflog_for_walk(revs->reflog_info,
136                                 (struct commit *)obj, name))
137                 return;
138         add_object_array_with_mode(obj, name, &revs->pending, mode);
139 }
140
141 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
142 {
143         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
144 }
145
146 void add_head_to_pending(struct rev_info *revs)
147 {
148         unsigned char sha1[20];
149         struct object *obj;
150         if (get_sha1("HEAD", sha1))
151                 return;
152         obj = parse_object(sha1);
153         if (!obj)
154                 return;
155         add_pending_object(revs, obj, "HEAD");
156 }
157
158 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
159 {
160         struct object *object;
161
162         object = parse_object(sha1);
163         if (!object)
164                 die("bad object %s", name);
165         object->flags |= flags;
166         return object;
167 }
168
169 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
170 {
171         unsigned long flags = object->flags;
172
173         /*
174          * Tag object? Look what it points to..
175          */
176         while (object->type == OBJ_TAG) {
177                 struct tag *tag = (struct tag *) object;
178                 if (revs->tag_objects && !(flags & UNINTERESTING))
179                         add_pending_object(revs, object, tag->tag);
180                 if (!tag->tagged)
181                         die("bad tag");
182                 object = parse_object(tag->tagged->sha1);
183                 if (!object)
184                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
185         }
186
187         /*
188          * Commit object? Just return it, we'll do all the complex
189          * reachability crud.
190          */
191         if (object->type == OBJ_COMMIT) {
192                 struct commit *commit = (struct commit *)object;
193                 if (parse_commit(commit) < 0)
194                         die("unable to parse commit %s", name);
195                 if (flags & UNINTERESTING) {
196                         commit->object.flags |= UNINTERESTING;
197                         mark_parents_uninteresting(commit);
198                         revs->limited = 1;
199                 }
200                 return commit;
201         }
202
203         /*
204          * Tree object? Either mark it uniniteresting, or add it
205          * to the list of objects to look at later..
206          */
207         if (object->type == OBJ_TREE) {
208                 struct tree *tree = (struct tree *)object;
209                 if (!revs->tree_objects)
210                         return NULL;
211                 if (flags & UNINTERESTING) {
212                         mark_tree_uninteresting(tree);
213                         return NULL;
214                 }
215                 add_pending_object(revs, object, "");
216                 return NULL;
217         }
218
219         /*
220          * Blob object? You know the drill by now..
221          */
222         if (object->type == OBJ_BLOB) {
223                 struct blob *blob = (struct blob *)object;
224                 if (!revs->blob_objects)
225                         return NULL;
226                 if (flags & UNINTERESTING) {
227                         mark_blob_uninteresting(blob);
228                         return NULL;
229                 }
230                 add_pending_object(revs, object, "");
231                 return NULL;
232         }
233         die("%s is unknown object", name);
234 }
235
236 static int everybody_uninteresting(struct commit_list *orig)
237 {
238         struct commit_list *list = orig;
239         while (list) {
240                 struct commit *commit = list->item;
241                 list = list->next;
242                 if (commit->object.flags & UNINTERESTING)
243                         continue;
244                 return 0;
245         }
246         return 1;
247 }
248
249 /*
250  * The goal is to get REV_TREE_NEW as the result only if the
251  * diff consists of all '+' (and no other changes), and
252  * REV_TREE_DIFFERENT otherwise (of course if the trees are
253  * the same we want REV_TREE_SAME).  That means that once we
254  * get to REV_TREE_DIFFERENT, we do not have to look any further.
255  */
256 static int tree_difference = REV_TREE_SAME;
257
258 static void file_add_remove(struct diff_options *options,
259                     int addremove, unsigned mode,
260                     const unsigned char *sha1,
261                     const char *base, const char *path)
262 {
263         int diff = REV_TREE_DIFFERENT;
264
265         /*
266          * Is it an add of a new file? It means that the old tree
267          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
268          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
269          * (and if it already was "REV_TREE_NEW", we'll keep it
270          * "REV_TREE_NEW" of course).
271          */
272         if (addremove == '+') {
273                 diff = tree_difference;
274                 if (diff != REV_TREE_SAME)
275                         return;
276                 diff = REV_TREE_NEW;
277         }
278         tree_difference = diff;
279         if (tree_difference == REV_TREE_DIFFERENT)
280                 DIFF_OPT_SET(options, HAS_CHANGES);
281 }
282
283 static void file_change(struct diff_options *options,
284                  unsigned old_mode, unsigned new_mode,
285                  const unsigned char *old_sha1,
286                  const unsigned char *new_sha1,
287                  const char *base, const char *path)
288 {
289         tree_difference = REV_TREE_DIFFERENT;
290         DIFF_OPT_SET(options, HAS_CHANGES);
291 }
292
293 static int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
294 {
295         if (!t1)
296                 return REV_TREE_NEW;
297         if (!t2)
298                 return REV_TREE_DIFFERENT;
299         tree_difference = REV_TREE_SAME;
300         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
301         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
302                            &revs->pruning) < 0)
303                 return REV_TREE_DIFFERENT;
304         return tree_difference;
305 }
306
307 static int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
308 {
309         int retval;
310         void *tree;
311         unsigned long size;
312         struct tree_desc empty, real;
313
314         if (!t1)
315                 return 0;
316
317         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
318         if (!tree)
319                 return 0;
320         init_tree_desc(&real, tree, size);
321         init_tree_desc(&empty, "", 0);
322
323         tree_difference = REV_TREE_SAME;
324         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
325         retval = diff_tree(&empty, &real, "", &revs->pruning);
326         free(tree);
327
328         return retval >= 0 && (tree_difference == REV_TREE_SAME);
329 }
330
331 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
332 {
333         struct commit_list **pp, *parent;
334         int tree_changed = 0, tree_same = 0;
335
336         /*
337          * If we don't do pruning, everything is interesting
338          */
339         if (!revs->prune)
340                 return;
341
342         if (!commit->tree)
343                 return;
344
345         if (!commit->parents) {
346                 if (rev_same_tree_as_empty(revs, commit->tree))
347                         commit->object.flags |= TREESAME;
348                 return;
349         }
350
351         /*
352          * Normal non-merge commit? If we don't want to make the
353          * history dense, we consider it always to be a change..
354          */
355         if (!revs->dense && !commit->parents->next)
356                 return;
357
358         pp = &commit->parents;
359         while ((parent = *pp) != NULL) {
360                 struct commit *p = parent->item;
361
362                 if (parse_commit(p) < 0)
363                         die("cannot simplify commit %s (because of %s)",
364                             sha1_to_hex(commit->object.sha1),
365                             sha1_to_hex(p->object.sha1));
366                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
367                 case REV_TREE_SAME:
368                         tree_same = 1;
369                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
370                                 /* Even if a merge with an uninteresting
371                                  * side branch brought the entire change
372                                  * we are interested in, we do not want
373                                  * to lose the other branches of this
374                                  * merge, so we just keep going.
375                                  */
376                                 pp = &parent->next;
377                                 continue;
378                         }
379                         parent->next = NULL;
380                         commit->parents = parent;
381                         commit->object.flags |= TREESAME;
382                         return;
383
384                 case REV_TREE_NEW:
385                         if (revs->remove_empty_trees &&
386                             rev_same_tree_as_empty(revs, p->tree)) {
387                                 /* We are adding all the specified
388                                  * paths from this parent, so the
389                                  * history beyond this parent is not
390                                  * interesting.  Remove its parents
391                                  * (they are grandparents for us).
392                                  * IOW, we pretend this parent is a
393                                  * "root" commit.
394                                  */
395                                 if (parse_commit(p) < 0)
396                                         die("cannot simplify commit %s (invalid %s)",
397                                             sha1_to_hex(commit->object.sha1),
398                                             sha1_to_hex(p->object.sha1));
399                                 p->parents = NULL;
400                         }
401                 /* fallthrough */
402                 case REV_TREE_DIFFERENT:
403                         tree_changed = 1;
404                         pp = &parent->next;
405                         continue;
406                 }
407                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
408         }
409         if (tree_changed && !tree_same)
410                 return;
411         commit->object.flags |= TREESAME;
412 }
413
414 static int add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
415 {
416         struct commit_list *parent = commit->parents;
417         unsigned left_flag;
418
419         if (commit->object.flags & ADDED)
420                 return 0;
421         commit->object.flags |= ADDED;
422
423         /*
424          * If the commit is uninteresting, don't try to
425          * prune parents - we want the maximal uninteresting
426          * set.
427          *
428          * Normally we haven't parsed the parent
429          * yet, so we won't have a parent of a parent
430          * here. However, it may turn out that we've
431          * reached this commit some other way (where it
432          * wasn't uninteresting), in which case we need
433          * to mark its parents recursively too..
434          */
435         if (commit->object.flags & UNINTERESTING) {
436                 while (parent) {
437                         struct commit *p = parent->item;
438                         parent = parent->next;
439                         if (parse_commit(p) < 0)
440                                 return -1;
441                         p->object.flags |= UNINTERESTING;
442                         if (p->parents)
443                                 mark_parents_uninteresting(p);
444                         if (p->object.flags & SEEN)
445                                 continue;
446                         p->object.flags |= SEEN;
447                         insert_by_date(p, list);
448                 }
449                 return 0;
450         }
451
452         /*
453          * Ok, the commit wasn't uninteresting. Try to
454          * simplify the commit history and find the parent
455          * that has no differences in the path set if one exists.
456          */
457         try_to_simplify_commit(revs, commit);
458
459         if (revs->no_walk)
460                 return 0;
461
462         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
463
464         for (parent = commit->parents; parent; parent = parent->next) {
465                 struct commit *p = parent->item;
466
467                 if (parse_commit(p) < 0)
468                         return -1;
469                 p->object.flags |= left_flag;
470                 if (!(p->object.flags & SEEN)) {
471                         p->object.flags |= SEEN;
472                         insert_by_date(p, list);
473                 }
474                 if(revs->first_parent_only)
475                         break;
476         }
477         return 0;
478 }
479
480 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
481 {
482         struct commit_list *p;
483         int left_count = 0, right_count = 0;
484         int left_first;
485         struct patch_ids ids;
486
487         /* First count the commits on the left and on the right */
488         for (p = list; p; p = p->next) {
489                 struct commit *commit = p->item;
490                 unsigned flags = commit->object.flags;
491                 if (flags & BOUNDARY)
492                         ;
493                 else if (flags & SYMMETRIC_LEFT)
494                         left_count++;
495                 else
496                         right_count++;
497         }
498
499         left_first = left_count < right_count;
500         init_patch_ids(&ids);
501         if (revs->diffopt.nr_paths) {
502                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
503                 ids.diffopts.paths = revs->diffopt.paths;
504                 ids.diffopts.pathlens = revs->diffopt.pathlens;
505         }
506
507         /* Compute patch-ids for one side */
508         for (p = list; p; p = p->next) {
509                 struct commit *commit = p->item;
510                 unsigned flags = commit->object.flags;
511
512                 if (flags & BOUNDARY)
513                         continue;
514                 /*
515                  * If we have fewer left, left_first is set and we omit
516                  * commits on the right branch in this loop.  If we have
517                  * fewer right, we skip the left ones.
518                  */
519                 if (left_first != !!(flags & SYMMETRIC_LEFT))
520                         continue;
521                 commit->util = add_commit_patch_id(commit, &ids);
522         }
523
524         /* Check the other side */
525         for (p = list; p; p = p->next) {
526                 struct commit *commit = p->item;
527                 struct patch_id *id;
528                 unsigned flags = commit->object.flags;
529
530                 if (flags & BOUNDARY)
531                         continue;
532                 /*
533                  * If we have fewer left, left_first is set and we omit
534                  * commits on the left branch in this loop.
535                  */
536                 if (left_first == !!(flags & SYMMETRIC_LEFT))
537                         continue;
538
539                 /*
540                  * Have we seen the same patch id?
541                  */
542                 id = has_commit_patch_id(commit, &ids);
543                 if (!id)
544                         continue;
545                 id->seen = 1;
546                 commit->object.flags |= SHOWN;
547         }
548
549         /* Now check the original side for seen ones */
550         for (p = list; p; p = p->next) {
551                 struct commit *commit = p->item;
552                 struct patch_id *ent;
553
554                 ent = commit->util;
555                 if (!ent)
556                         continue;
557                 if (ent->seen)
558                         commit->object.flags |= SHOWN;
559                 commit->util = NULL;
560         }
561
562         free_patch_ids(&ids);
563 }
564
565 /* How many extra uninteresting commits we want to see.. */
566 #define SLOP 5
567
568 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
569 {
570         /*
571          * No source list at all? We're definitely done..
572          */
573         if (!src)
574                 return 0;
575
576         /*
577          * Does the destination list contain entries with a date
578          * before the source list? Definitely _not_ done.
579          */
580         if (date < src->item->date)
581                 return SLOP;
582
583         /*
584          * Does the source list still have interesting commits in
585          * it? Definitely not done..
586          */
587         if (!everybody_uninteresting(src))
588                 return SLOP;
589
590         /* Ok, we're closing in.. */
591         return slop-1;
592 }
593
594 static int limit_list(struct rev_info *revs)
595 {
596         int slop = SLOP;
597         unsigned long date = ~0ul;
598         struct commit_list *list = revs->commits;
599         struct commit_list *newlist = NULL;
600         struct commit_list **p = &newlist;
601
602         while (list) {
603                 struct commit_list *entry = list;
604                 struct commit *commit = list->item;
605                 struct object *obj = &commit->object;
606                 show_early_output_fn_t show;
607
608                 list = list->next;
609                 free(entry);
610
611                 if (revs->max_age != -1 && (commit->date < revs->max_age))
612                         obj->flags |= UNINTERESTING;
613                 if (add_parents_to_list(revs, commit, &list) < 0)
614                         return -1;
615                 if (obj->flags & UNINTERESTING) {
616                         mark_parents_uninteresting(commit);
617                         if (revs->show_all)
618                                 p = &commit_list_insert(commit, p)->next;
619                         slop = still_interesting(list, date, slop);
620                         if (slop)
621                                 continue;
622                         /* If showing all, add the whole pending list to the end */
623                         if (revs->show_all)
624                                 *p = list;
625                         break;
626                 }
627                 if (revs->min_age != -1 && (commit->date > revs->min_age))
628                         continue;
629                 date = commit->date;
630                 p = &commit_list_insert(commit, p)->next;
631
632                 show = show_early_output;
633                 if (!show)
634                         continue;
635
636                 show(revs, newlist);
637                 show_early_output = NULL;
638         }
639         if (revs->cherry_pick)
640                 cherry_pick_list(newlist, revs);
641
642         revs->commits = newlist;
643         return 0;
644 }
645
646 struct all_refs_cb {
647         int all_flags;
648         int warned_bad_reflog;
649         struct rev_info *all_revs;
650         const char *name_for_errormsg;
651 };
652
653 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
654 {
655         struct all_refs_cb *cb = cb_data;
656         struct object *object = get_reference(cb->all_revs, path, sha1,
657                                               cb->all_flags);
658         add_pending_object(cb->all_revs, object, path);
659         return 0;
660 }
661
662 static void handle_refs(struct rev_info *revs, unsigned flags,
663                 int (*for_each)(each_ref_fn, void *))
664 {
665         struct all_refs_cb cb;
666         cb.all_revs = revs;
667         cb.all_flags = flags;
668         for_each(handle_one_ref, &cb);
669 }
670
671 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
672 {
673         struct all_refs_cb *cb = cb_data;
674         if (!is_null_sha1(sha1)) {
675                 struct object *o = parse_object(sha1);
676                 if (o) {
677                         o->flags |= cb->all_flags;
678                         add_pending_object(cb->all_revs, o, "");
679                 }
680                 else if (!cb->warned_bad_reflog) {
681                         warning("reflog of '%s' references pruned commits",
682                                 cb->name_for_errormsg);
683                         cb->warned_bad_reflog = 1;
684                 }
685         }
686 }
687
688 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
689                 const char *email, unsigned long timestamp, int tz,
690                 const char *message, void *cb_data)
691 {
692         handle_one_reflog_commit(osha1, cb_data);
693         handle_one_reflog_commit(nsha1, cb_data);
694         return 0;
695 }
696
697 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
698 {
699         struct all_refs_cb *cb = cb_data;
700         cb->warned_bad_reflog = 0;
701         cb->name_for_errormsg = path;
702         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
703         return 0;
704 }
705
706 static void handle_reflog(struct rev_info *revs, unsigned flags)
707 {
708         struct all_refs_cb cb;
709         cb.all_revs = revs;
710         cb.all_flags = flags;
711         for_each_reflog(handle_one_reflog, &cb);
712 }
713
714 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
715 {
716         unsigned char sha1[20];
717         struct object *it;
718         struct commit *commit;
719         struct commit_list *parents;
720
721         if (*arg == '^') {
722                 flags ^= UNINTERESTING;
723                 arg++;
724         }
725         if (get_sha1(arg, sha1))
726                 return 0;
727         while (1) {
728                 it = get_reference(revs, arg, sha1, 0);
729                 if (it->type != OBJ_TAG)
730                         break;
731                 if (!((struct tag*)it)->tagged)
732                         return 0;
733                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
734         }
735         if (it->type != OBJ_COMMIT)
736                 return 0;
737         commit = (struct commit *)it;
738         for (parents = commit->parents; parents; parents = parents->next) {
739                 it = &parents->item->object;
740                 it->flags |= flags;
741                 add_pending_object(revs, it, arg);
742         }
743         return 1;
744 }
745
746 void init_revisions(struct rev_info *revs, const char *prefix)
747 {
748         memset(revs, 0, sizeof(*revs));
749
750         revs->abbrev = DEFAULT_ABBREV;
751         revs->ignore_merges = 1;
752         revs->simplify_history = 1;
753         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
754         DIFF_OPT_SET(&revs->pruning, QUIET);
755         revs->pruning.add_remove = file_add_remove;
756         revs->pruning.change = file_change;
757         revs->lifo = 1;
758         revs->dense = 1;
759         revs->prefix = prefix;
760         revs->max_age = -1;
761         revs->min_age = -1;
762         revs->skip_count = -1;
763         revs->max_count = -1;
764
765         revs->commit_format = CMIT_FMT_DEFAULT;
766
767         diff_setup(&revs->diffopt);
768         if (prefix && !revs->diffopt.prefix) {
769                 revs->diffopt.prefix = prefix;
770                 revs->diffopt.prefix_length = strlen(prefix);
771         }
772 }
773
774 static void add_pending_commit_list(struct rev_info *revs,
775                                     struct commit_list *commit_list,
776                                     unsigned int flags)
777 {
778         while (commit_list) {
779                 struct object *object = &commit_list->item->object;
780                 object->flags |= flags;
781                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
782                 commit_list = commit_list->next;
783         }
784 }
785
786 static void prepare_show_merge(struct rev_info *revs)
787 {
788         struct commit_list *bases;
789         struct commit *head, *other;
790         unsigned char sha1[20];
791         const char **prune = NULL;
792         int i, prune_num = 1; /* counting terminating NULL */
793
794         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
795                 die("--merge without HEAD?");
796         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
797                 die("--merge without MERGE_HEAD?");
798         add_pending_object(revs, &head->object, "HEAD");
799         add_pending_object(revs, &other->object, "MERGE_HEAD");
800         bases = get_merge_bases(head, other, 1);
801         add_pending_commit_list(revs, bases, UNINTERESTING);
802         free_commit_list(bases);
803         head->object.flags |= SYMMETRIC_LEFT;
804
805         if (!active_nr)
806                 read_cache();
807         for (i = 0; i < active_nr; i++) {
808                 struct cache_entry *ce = active_cache[i];
809                 if (!ce_stage(ce))
810                         continue;
811                 if (ce_path_match(ce, revs->prune_data)) {
812                         prune_num++;
813                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
814                         prune[prune_num-2] = ce->name;
815                         prune[prune_num-1] = NULL;
816                 }
817                 while ((i+1 < active_nr) &&
818                        ce_same_name(ce, active_cache[i+1]))
819                         i++;
820         }
821         revs->prune_data = prune;
822         revs->limited = 1;
823 }
824
825 int handle_revision_arg(const char *arg, struct rev_info *revs,
826                         int flags,
827                         int cant_be_filename)
828 {
829         unsigned mode;
830         char *dotdot;
831         struct object *object;
832         unsigned char sha1[20];
833         int local_flags;
834
835         dotdot = strstr(arg, "..");
836         if (dotdot) {
837                 unsigned char from_sha1[20];
838                 const char *next = dotdot + 2;
839                 const char *this = arg;
840                 int symmetric = *next == '.';
841                 unsigned int flags_exclude = flags ^ UNINTERESTING;
842
843                 *dotdot = 0;
844                 next += symmetric;
845
846                 if (!*next)
847                         next = "HEAD";
848                 if (dotdot == arg)
849                         this = "HEAD";
850                 if (!get_sha1(this, from_sha1) &&
851                     !get_sha1(next, sha1)) {
852                         struct commit *a, *b;
853                         struct commit_list *exclude;
854
855                         a = lookup_commit_reference(from_sha1);
856                         b = lookup_commit_reference(sha1);
857                         if (!a || !b) {
858                                 die(symmetric ?
859                                     "Invalid symmetric difference expression %s...%s" :
860                                     "Invalid revision range %s..%s",
861                                     arg, next);
862                         }
863
864                         if (!cant_be_filename) {
865                                 *dotdot = '.';
866                                 verify_non_filename(revs->prefix, arg);
867                         }
868
869                         if (symmetric) {
870                                 exclude = get_merge_bases(a, b, 1);
871                                 add_pending_commit_list(revs, exclude,
872                                                         flags_exclude);
873                                 free_commit_list(exclude);
874                                 a->object.flags |= flags | SYMMETRIC_LEFT;
875                         } else
876                                 a->object.flags |= flags_exclude;
877                         b->object.flags |= flags;
878                         add_pending_object(revs, &a->object, this);
879                         add_pending_object(revs, &b->object, next);
880                         return 0;
881                 }
882                 *dotdot = '.';
883         }
884         dotdot = strstr(arg, "^@");
885         if (dotdot && !dotdot[2]) {
886                 *dotdot = 0;
887                 if (add_parents_only(revs, arg, flags))
888                         return 0;
889                 *dotdot = '^';
890         }
891         dotdot = strstr(arg, "^!");
892         if (dotdot && !dotdot[2]) {
893                 *dotdot = 0;
894                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
895                         *dotdot = '^';
896         }
897
898         local_flags = 0;
899         if (*arg == '^') {
900                 local_flags = UNINTERESTING;
901                 arg++;
902         }
903         if (get_sha1_with_mode(arg, sha1, &mode))
904                 return -1;
905         if (!cant_be_filename)
906                 verify_non_filename(revs->prefix, arg);
907         object = get_reference(revs, arg, sha1, flags ^ local_flags);
908         add_pending_object_with_mode(revs, object, arg, mode);
909         return 0;
910 }
911
912 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
913 {
914         if (!revs->grep_filter) {
915                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
916                 opt->status_only = 1;
917                 opt->pattern_tail = &(opt->pattern_list);
918                 opt->regflags = REG_NEWLINE;
919                 revs->grep_filter = opt;
920         }
921         append_grep_pattern(revs->grep_filter, ptn,
922                             "command line", 0, what);
923 }
924
925 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
926 {
927         char *pat;
928         const char *prefix;
929         int patlen, fldlen;
930
931         fldlen = strlen(field);
932         patlen = strlen(pattern);
933         pat = xmalloc(patlen + fldlen + 10);
934         prefix = ".*";
935         if (*pattern == '^') {
936                 prefix = "";
937                 pattern++;
938         }
939         sprintf(pat, "^%s %s%s", field, prefix, pattern);
940         add_grep(revs, pat, GREP_PATTERN_HEAD);
941 }
942
943 static void add_message_grep(struct rev_info *revs, const char *pattern)
944 {
945         add_grep(revs, pattern, GREP_PATTERN_BODY);
946 }
947
948 static void add_ignore_packed(struct rev_info *revs, const char *name)
949 {
950         int num = ++revs->num_ignore_packed;
951
952         revs->ignore_packed = xrealloc(revs->ignore_packed,
953                                        sizeof(const char **) * (num + 1));
954         revs->ignore_packed[num-1] = name;
955         revs->ignore_packed[num] = NULL;
956 }
957
958 /*
959  * Parse revision information, filling in the "rev_info" structure,
960  * and removing the used arguments from the argument list.
961  *
962  * Returns the number of arguments left that weren't recognized
963  * (which are also moved to the head of the argument list)
964  */
965 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
966 {
967         int i, flags, seen_dashdash, show_merge;
968         const char **unrecognized = argv + 1;
969         int left = 1;
970         int all_match = 0;
971         int regflags = 0;
972         int fixed = 0;
973
974         /* First, search for "--" */
975         seen_dashdash = 0;
976         for (i = 1; i < argc; i++) {
977                 const char *arg = argv[i];
978                 if (strcmp(arg, "--"))
979                         continue;
980                 argv[i] = NULL;
981                 argc = i;
982                 if (argv[i + 1])
983                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
984                 seen_dashdash = 1;
985                 break;
986         }
987
988         flags = show_merge = 0;
989         for (i = 1; i < argc; i++) {
990                 const char *arg = argv[i];
991                 if (*arg == '-') {
992                         int opts;
993                         if (!prefixcmp(arg, "--max-count=")) {
994                                 revs->max_count = atoi(arg + 12);
995                                 continue;
996                         }
997                         if (!prefixcmp(arg, "--skip=")) {
998                                 revs->skip_count = atoi(arg + 7);
999                                 continue;
1000                         }
1001                         /* accept -<digit>, like traditional "head" */
1002                         if ((*arg == '-') && isdigit(arg[1])) {
1003                                 revs->max_count = atoi(arg + 1);
1004                                 continue;
1005                         }
1006                         if (!strcmp(arg, "-n")) {
1007                                 if (argc <= i + 1)
1008                                         die("-n requires an argument");
1009                                 revs->max_count = atoi(argv[++i]);
1010                                 continue;
1011                         }
1012                         if (!prefixcmp(arg, "-n")) {
1013                                 revs->max_count = atoi(arg + 2);
1014                                 continue;
1015                         }
1016                         if (!prefixcmp(arg, "--max-age=")) {
1017                                 revs->max_age = atoi(arg + 10);
1018                                 continue;
1019                         }
1020                         if (!prefixcmp(arg, "--since=")) {
1021                                 revs->max_age = approxidate(arg + 8);
1022                                 continue;
1023                         }
1024                         if (!prefixcmp(arg, "--after=")) {
1025                                 revs->max_age = approxidate(arg + 8);
1026                                 continue;
1027                         }
1028                         if (!prefixcmp(arg, "--min-age=")) {
1029                                 revs->min_age = atoi(arg + 10);
1030                                 continue;
1031                         }
1032                         if (!prefixcmp(arg, "--before=")) {
1033                                 revs->min_age = approxidate(arg + 9);
1034                                 continue;
1035                         }
1036                         if (!prefixcmp(arg, "--until=")) {
1037                                 revs->min_age = approxidate(arg + 8);
1038                                 continue;
1039                         }
1040                         if (!strcmp(arg, "--all")) {
1041                                 handle_refs(revs, flags, for_each_ref);
1042                                 continue;
1043                         }
1044                         if (!strcmp(arg, "--branches")) {
1045                                 handle_refs(revs, flags, for_each_branch_ref);
1046                                 continue;
1047                         }
1048                         if (!strcmp(arg, "--tags")) {
1049                                 handle_refs(revs, flags, for_each_tag_ref);
1050                                 continue;
1051                         }
1052                         if (!strcmp(arg, "--remotes")) {
1053                                 handle_refs(revs, flags, for_each_remote_ref);
1054                                 continue;
1055                         }
1056                         if (!strcmp(arg, "--first-parent")) {
1057                                 revs->first_parent_only = 1;
1058                                 continue;
1059                         }
1060                         if (!strcmp(arg, "--reflog")) {
1061                                 handle_reflog(revs, flags);
1062                                 continue;
1063                         }
1064                         if (!strcmp(arg, "-g") ||
1065                                         !strcmp(arg, "--walk-reflogs")) {
1066                                 init_reflog_walk(&revs->reflog_info);
1067                                 continue;
1068                         }
1069                         if (!strcmp(arg, "--not")) {
1070                                 flags ^= UNINTERESTING;
1071                                 continue;
1072                         }
1073                         if (!strcmp(arg, "--default")) {
1074                                 if (++i >= argc)
1075                                         die("bad --default argument");
1076                                 def = argv[i];
1077                                 continue;
1078                         }
1079                         if (!strcmp(arg, "--merge")) {
1080                                 show_merge = 1;
1081                                 continue;
1082                         }
1083                         if (!strcmp(arg, "--topo-order")) {
1084                                 revs->lifo = 1;
1085                                 revs->topo_order = 1;
1086                                 continue;
1087                         }
1088                         if (!strcmp(arg, "--date-order")) {
1089                                 revs->lifo = 0;
1090                                 revs->topo_order = 1;
1091                                 continue;
1092                         }
1093                         if (!prefixcmp(arg, "--early-output")) {
1094                                 int count = 100;
1095                                 switch (arg[14]) {
1096                                 case '=':
1097                                         count = atoi(arg+15);
1098                                         /* Fallthrough */
1099                                 case 0:
1100                                         revs->topo_order = 1;
1101                                         revs->early_output = count;
1102                                         continue;
1103                                 }
1104                         }
1105                         if (!strcmp(arg, "--parents")) {
1106                                 revs->parents = 1;
1107                                 continue;
1108                         }
1109                         if (!strcmp(arg, "--dense")) {
1110                                 revs->dense = 1;
1111                                 continue;
1112                         }
1113                         if (!strcmp(arg, "--sparse")) {
1114                                 revs->dense = 0;
1115                                 continue;
1116                         }
1117                         if (!strcmp(arg, "--show-all")) {
1118                                 revs->show_all = 1;
1119                                 continue;
1120                         }
1121                         if (!strcmp(arg, "--remove-empty")) {
1122                                 revs->remove_empty_trees = 1;
1123                                 continue;
1124                         }
1125                         if (!strcmp(arg, "--no-merges")) {
1126                                 revs->no_merges = 1;
1127                                 continue;
1128                         }
1129                         if (!strcmp(arg, "--boundary")) {
1130                                 revs->boundary = 1;
1131                                 continue;
1132                         }
1133                         if (!strcmp(arg, "--left-right")) {
1134                                 revs->left_right = 1;
1135                                 continue;
1136                         }
1137                         if (!strcmp(arg, "--cherry-pick")) {
1138                                 revs->cherry_pick = 1;
1139                                 revs->limited = 1;
1140                                 continue;
1141                         }
1142                         if (!strcmp(arg, "--objects")) {
1143                                 revs->tag_objects = 1;
1144                                 revs->tree_objects = 1;
1145                                 revs->blob_objects = 1;
1146                                 continue;
1147                         }
1148                         if (!strcmp(arg, "--objects-edge")) {
1149                                 revs->tag_objects = 1;
1150                                 revs->tree_objects = 1;
1151                                 revs->blob_objects = 1;
1152                                 revs->edge_hint = 1;
1153                                 continue;
1154                         }
1155                         if (!strcmp(arg, "--unpacked")) {
1156                                 revs->unpacked = 1;
1157                                 free(revs->ignore_packed);
1158                                 revs->ignore_packed = NULL;
1159                                 revs->num_ignore_packed = 0;
1160                                 continue;
1161                         }
1162                         if (!prefixcmp(arg, "--unpacked=")) {
1163                                 revs->unpacked = 1;
1164                                 add_ignore_packed(revs, arg+11);
1165                                 continue;
1166                         }
1167                         if (!strcmp(arg, "-r")) {
1168                                 revs->diff = 1;
1169                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1170                                 continue;
1171                         }
1172                         if (!strcmp(arg, "-t")) {
1173                                 revs->diff = 1;
1174                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1175                                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1176                                 continue;
1177                         }
1178                         if (!strcmp(arg, "-m")) {
1179                                 revs->ignore_merges = 0;
1180                                 continue;
1181                         }
1182                         if (!strcmp(arg, "-c")) {
1183                                 revs->diff = 1;
1184                                 revs->dense_combined_merges = 0;
1185                                 revs->combine_merges = 1;
1186                                 continue;
1187                         }
1188                         if (!strcmp(arg, "--cc")) {
1189                                 revs->diff = 1;
1190                                 revs->dense_combined_merges = 1;
1191                                 revs->combine_merges = 1;
1192                                 continue;
1193                         }
1194                         if (!strcmp(arg, "-v")) {
1195                                 revs->verbose_header = 1;
1196                                 continue;
1197                         }
1198                         if (!prefixcmp(arg, "--pretty")) {
1199                                 revs->verbose_header = 1;
1200                                 get_commit_format(arg+8, revs);
1201                                 continue;
1202                         }
1203                         if (!strcmp(arg, "--root")) {
1204                                 revs->show_root_diff = 1;
1205                                 continue;
1206                         }
1207                         if (!strcmp(arg, "--no-commit-id")) {
1208                                 revs->no_commit_id = 1;
1209                                 continue;
1210                         }
1211                         if (!strcmp(arg, "--always")) {
1212                                 revs->always_show_header = 1;
1213                                 continue;
1214                         }
1215                         if (!strcmp(arg, "--no-abbrev")) {
1216                                 revs->abbrev = 0;
1217                                 continue;
1218                         }
1219                         if (!strcmp(arg, "--abbrev")) {
1220                                 revs->abbrev = DEFAULT_ABBREV;
1221                                 continue;
1222                         }
1223                         if (!prefixcmp(arg, "--abbrev=")) {
1224                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1225                                 if (revs->abbrev < MINIMUM_ABBREV)
1226                                         revs->abbrev = MINIMUM_ABBREV;
1227                                 else if (revs->abbrev > 40)
1228                                         revs->abbrev = 40;
1229                                 continue;
1230                         }
1231                         if (!strcmp(arg, "--abbrev-commit")) {
1232                                 revs->abbrev_commit = 1;
1233                                 continue;
1234                         }
1235                         if (!strcmp(arg, "--full-diff")) {
1236                                 revs->diff = 1;
1237                                 revs->full_diff = 1;
1238                                 continue;
1239                         }
1240                         if (!strcmp(arg, "--full-history")) {
1241                                 revs->simplify_history = 0;
1242                                 continue;
1243                         }
1244                         if (!strcmp(arg, "--relative-date")) {
1245                                 revs->date_mode = DATE_RELATIVE;
1246                                 continue;
1247                         }
1248                         if (!strncmp(arg, "--date=", 7)) {
1249                                 revs->date_mode = parse_date_format(arg + 7);
1250                                 continue;
1251                         }
1252                         if (!strcmp(arg, "--log-size")) {
1253                                 revs->show_log_size = 1;
1254                                 continue;
1255                         }
1256
1257                         /*
1258                          * Grepping the commit log
1259                          */
1260                         if (!prefixcmp(arg, "--author=")) {
1261                                 add_header_grep(revs, "author", arg+9);
1262                                 continue;
1263                         }
1264                         if (!prefixcmp(arg, "--committer=")) {
1265                                 add_header_grep(revs, "committer", arg+12);
1266                                 continue;
1267                         }
1268                         if (!prefixcmp(arg, "--grep=")) {
1269                                 add_message_grep(revs, arg+7);
1270                                 continue;
1271                         }
1272                         if (!strcmp(arg, "--extended-regexp") ||
1273                             !strcmp(arg, "-E")) {
1274                                 regflags |= REG_EXTENDED;
1275                                 continue;
1276                         }
1277                         if (!strcmp(arg, "--regexp-ignore-case") ||
1278                             !strcmp(arg, "-i")) {
1279                                 regflags |= REG_ICASE;
1280                                 continue;
1281                         }
1282                         if (!strcmp(arg, "--fixed-strings") ||
1283                             !strcmp(arg, "-F")) {
1284                                 fixed = 1;
1285                                 continue;
1286                         }
1287                         if (!strcmp(arg, "--all-match")) {
1288                                 all_match = 1;
1289                                 continue;
1290                         }
1291                         if (!prefixcmp(arg, "--encoding=")) {
1292                                 arg += 11;
1293                                 if (strcmp(arg, "none"))
1294                                         git_log_output_encoding = xstrdup(arg);
1295                                 else
1296                                         git_log_output_encoding = "";
1297                                 continue;
1298                         }
1299                         if (!strcmp(arg, "--reverse")) {
1300                                 revs->reverse ^= 1;
1301                                 continue;
1302                         }
1303                         if (!strcmp(arg, "--no-walk")) {
1304                                 revs->no_walk = 1;
1305                                 continue;
1306                         }
1307                         if (!strcmp(arg, "--do-walk")) {
1308                                 revs->no_walk = 0;
1309                                 continue;
1310                         }
1311
1312                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
1313                         if (opts > 0) {
1314                                 i += opts - 1;
1315                                 continue;
1316                         }
1317                         *unrecognized++ = arg;
1318                         left++;
1319                         continue;
1320                 }
1321
1322                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1323                         int j;
1324                         if (seen_dashdash || *arg == '^')
1325                                 die("bad revision '%s'", arg);
1326
1327                         /* If we didn't have a "--":
1328                          * (1) all filenames must exist;
1329                          * (2) all rev-args must not be interpretable
1330                          *     as a valid filename.
1331                          * but the latter we have checked in the main loop.
1332                          */
1333                         for (j = i; j < argc; j++)
1334                                 verify_filename(revs->prefix, argv[j]);
1335
1336                         revs->prune_data = get_pathspec(revs->prefix,
1337                                                         argv + i);
1338                         break;
1339                 }
1340         }
1341
1342         if (revs->grep_filter) {
1343                 revs->grep_filter->regflags |= regflags;
1344                 revs->grep_filter->fixed = fixed;
1345         }
1346
1347         if (show_merge)
1348                 prepare_show_merge(revs);
1349         if (def && !revs->pending.nr) {
1350                 unsigned char sha1[20];
1351                 struct object *object;
1352                 unsigned mode;
1353                 if (get_sha1_with_mode(def, sha1, &mode))
1354                         die("bad default revision '%s'", def);
1355                 object = get_reference(revs, def, sha1, 0);
1356                 add_pending_object_with_mode(revs, object, def, mode);
1357         }
1358
1359         /* Did the user ask for any diff output? Run the diff! */
1360         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1361                 revs->diff = 1;
1362
1363         /* Pickaxe, diff-filter and rename following need diffs */
1364         if (revs->diffopt.pickaxe ||
1365             revs->diffopt.filter ||
1366             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1367                 revs->diff = 1;
1368
1369         if (revs->topo_order)
1370                 revs->limited = 1;
1371
1372         if (revs->prune_data) {
1373                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1374                 /* Can't prune commits with rename following: the paths change.. */
1375                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1376                         revs->prune = 1;
1377                 if (!revs->full_diff)
1378                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1379         }
1380         if (revs->combine_merges) {
1381                 revs->ignore_merges = 0;
1382                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1383                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1384         }
1385         revs->diffopt.abbrev = revs->abbrev;
1386         if (diff_setup_done(&revs->diffopt) < 0)
1387                 die("diff_setup_done failed");
1388
1389         if (revs->grep_filter) {
1390                 revs->grep_filter->all_match = all_match;
1391                 compile_grep_patterns(revs->grep_filter);
1392         }
1393
1394         if (revs->reverse && revs->reflog_info)
1395                 die("cannot combine --reverse with --walk-reflogs");
1396
1397         return left;
1398 }
1399
1400 int prepare_revision_walk(struct rev_info *revs)
1401 {
1402         int nr = revs->pending.nr;
1403         struct object_array_entry *e, *list;
1404
1405         e = list = revs->pending.objects;
1406         revs->pending.nr = 0;
1407         revs->pending.alloc = 0;
1408         revs->pending.objects = NULL;
1409         while (--nr >= 0) {
1410                 struct commit *commit = handle_commit(revs, e->item, e->name);
1411                 if (commit) {
1412                         if (!(commit->object.flags & SEEN)) {
1413                                 commit->object.flags |= SEEN;
1414                                 insert_by_date(commit, &revs->commits);
1415                         }
1416                 }
1417                 e++;
1418         }
1419         free(list);
1420
1421         if (revs->no_walk)
1422                 return 0;
1423         if (revs->limited)
1424                 if (limit_list(revs) < 0)
1425                         return -1;
1426         if (revs->topo_order)
1427                 sort_in_topological_order(&revs->commits, revs->lifo);
1428         return 0;
1429 }
1430
1431 enum rewrite_result {
1432         rewrite_one_ok,
1433         rewrite_one_noparents,
1434         rewrite_one_error,
1435 };
1436
1437 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1438 {
1439         for (;;) {
1440                 struct commit *p = *pp;
1441                 if (!revs->limited)
1442                         if (add_parents_to_list(revs, p, &revs->commits) < 0)
1443                                 return rewrite_one_error;
1444                 if (p->parents && p->parents->next)
1445                         return rewrite_one_ok;
1446                 if (p->object.flags & UNINTERESTING)
1447                         return rewrite_one_ok;
1448                 if (!(p->object.flags & TREESAME))
1449                         return rewrite_one_ok;
1450                 if (!p->parents)
1451                         return rewrite_one_noparents;
1452                 *pp = p->parents->item;
1453         }
1454 }
1455
1456 static void remove_duplicate_parents(struct commit *commit)
1457 {
1458         struct commit_list **pp, *p;
1459
1460         /* Examine existing parents while marking ones we have seen... */
1461         pp = &commit->parents;
1462         while ((p = *pp) != NULL) {
1463                 struct commit *parent = p->item;
1464                 if (parent->object.flags & TMP_MARK) {
1465                         *pp = p->next;
1466                         continue;
1467                 }
1468                 parent->object.flags |= TMP_MARK;
1469                 pp = &p->next;
1470         }
1471         /* ... and clear the temporary mark */
1472         for (p = commit->parents; p; p = p->next)
1473                 p->item->object.flags &= ~TMP_MARK;
1474 }
1475
1476 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1477 {
1478         struct commit_list **pp = &commit->parents;
1479         while (*pp) {
1480                 struct commit_list *parent = *pp;
1481                 switch (rewrite_one(revs, &parent->item)) {
1482                 case rewrite_one_ok:
1483                         break;
1484                 case rewrite_one_noparents:
1485                         *pp = parent->next;
1486                         continue;
1487                 case rewrite_one_error:
1488                         return -1;
1489                 }
1490                 pp = &parent->next;
1491         }
1492         remove_duplicate_parents(commit);
1493         return 0;
1494 }
1495
1496 static int commit_match(struct commit *commit, struct rev_info *opt)
1497 {
1498         if (!opt->grep_filter)
1499                 return 1;
1500         return grep_buffer(opt->grep_filter,
1501                            NULL, /* we say nothing, not even filename */
1502                            commit->buffer, strlen(commit->buffer));
1503 }
1504
1505 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1506 {
1507         if (commit->object.flags & SHOWN)
1508                 return commit_ignore;
1509         if (revs->unpacked && has_sha1_pack(commit->object.sha1, revs->ignore_packed))
1510                 return commit_ignore;
1511         if (revs->show_all)
1512                 return commit_show;
1513         if (commit->object.flags & UNINTERESTING)
1514                 return commit_ignore;
1515         if (revs->min_age != -1 && (commit->date > revs->min_age))
1516                 return commit_ignore;
1517         if (revs->no_merges && commit->parents && commit->parents->next)
1518                 return commit_ignore;
1519         if (!commit_match(commit, revs))
1520                 return commit_ignore;
1521         if (revs->prune && revs->dense) {
1522                 /* Commit without changes? */
1523                 if (commit->object.flags & TREESAME) {
1524                         /* drop merges unless we want parenthood */
1525                         if (!revs->parents)
1526                                 return commit_ignore;
1527                         /* non-merge - always ignore it */
1528                         if (!commit->parents || !commit->parents->next)
1529                                 return commit_ignore;
1530                 }
1531                 if (revs->parents && rewrite_parents(revs, commit) < 0)
1532                         return commit_error;
1533         }
1534         return commit_show;
1535 }
1536
1537 static struct commit *get_revision_1(struct rev_info *revs)
1538 {
1539         if (!revs->commits)
1540                 return NULL;
1541
1542         do {
1543                 struct commit_list *entry = revs->commits;
1544                 struct commit *commit = entry->item;
1545
1546                 revs->commits = entry->next;
1547                 free(entry);
1548
1549                 if (revs->reflog_info)
1550                         fake_reflog_parent(revs->reflog_info, commit);
1551
1552                 /*
1553                  * If we haven't done the list limiting, we need to look at
1554                  * the parents here. We also need to do the date-based limiting
1555                  * that we'd otherwise have done in limit_list().
1556                  */
1557                 if (!revs->limited) {
1558                         if (revs->max_age != -1 &&
1559                             (commit->date < revs->max_age))
1560                                 continue;
1561                         if (add_parents_to_list(revs, commit, &revs->commits) < 0)
1562                                 return NULL;
1563                 }
1564
1565                 switch (simplify_commit(revs, commit)) {
1566                 case commit_ignore:
1567                         continue;
1568                 case commit_error:
1569                         return NULL;
1570                 default:
1571                         return commit;
1572                 }
1573         } while (revs->commits);
1574         return NULL;
1575 }
1576
1577 static void gc_boundary(struct object_array *array)
1578 {
1579         unsigned nr = array->nr;
1580         unsigned alloc = array->alloc;
1581         struct object_array_entry *objects = array->objects;
1582
1583         if (alloc <= nr) {
1584                 unsigned i, j;
1585                 for (i = j = 0; i < nr; i++) {
1586                         if (objects[i].item->flags & SHOWN)
1587                                 continue;
1588                         if (i != j)
1589                                 objects[j] = objects[i];
1590                         j++;
1591                 }
1592                 for (i = j; i < nr; i++)
1593                         objects[i].item = NULL;
1594                 array->nr = j;
1595         }
1596 }
1597
1598 struct commit *get_revision(struct rev_info *revs)
1599 {
1600         struct commit *c = NULL;
1601         struct commit_list *l;
1602
1603         if (revs->boundary == 2) {
1604                 unsigned i;
1605                 struct object_array *array = &revs->boundary_commits;
1606                 struct object_array_entry *objects = array->objects;
1607                 for (i = 0; i < array->nr; i++) {
1608                         c = (struct commit *)(objects[i].item);
1609                         if (!c)
1610                                 continue;
1611                         if (!(c->object.flags & CHILD_SHOWN))
1612                                 continue;
1613                         if (!(c->object.flags & SHOWN))
1614                                 break;
1615                 }
1616                 if (array->nr <= i)
1617                         return NULL;
1618
1619                 c->object.flags |= SHOWN | BOUNDARY;
1620                 return c;
1621         }
1622
1623         if (revs->reverse) {
1624                 int limit = -1;
1625
1626                 if (0 <= revs->max_count) {
1627                         limit = revs->max_count;
1628                         if (0 < revs->skip_count)
1629                                 limit += revs->skip_count;
1630                 }
1631                 l = NULL;
1632                 while ((c = get_revision_1(revs))) {
1633                         commit_list_insert(c, &l);
1634                         if ((0 < limit) && !--limit)
1635                                 break;
1636                 }
1637                 revs->commits = l;
1638                 revs->reverse = 0;
1639                 revs->max_count = -1;
1640                 c = NULL;
1641         }
1642
1643         /*
1644          * Now pick up what they want to give us
1645          */
1646         c = get_revision_1(revs);
1647         if (c) {
1648                 while (0 < revs->skip_count) {
1649                         revs->skip_count--;
1650                         c = get_revision_1(revs);
1651                         if (!c)
1652                                 break;
1653                 }
1654         }
1655
1656         /*
1657          * Check the max_count.
1658          */
1659         switch (revs->max_count) {
1660         case -1:
1661                 break;
1662         case 0:
1663                 c = NULL;
1664                 break;
1665         default:
1666                 revs->max_count--;
1667         }
1668
1669         if (c)
1670                 c->object.flags |= SHOWN;
1671
1672         if (!revs->boundary) {
1673                 return c;
1674         }
1675
1676         if (!c) {
1677                 /*
1678                  * get_revision_1() runs out the commits, and
1679                  * we are done computing the boundaries.
1680                  * switch to boundary commits output mode.
1681                  */
1682                 revs->boundary = 2;
1683                 return get_revision(revs);
1684         }
1685
1686         /*
1687          * boundary commits are the commits that are parents of the
1688          * ones we got from get_revision_1() but they themselves are
1689          * not returned from get_revision_1().  Before returning
1690          * 'c', we need to mark its parents that they could be boundaries.
1691          */
1692
1693         for (l = c->parents; l; l = l->next) {
1694                 struct object *p;
1695                 p = &(l->item->object);
1696                 if (p->flags & (CHILD_SHOWN | SHOWN))
1697                         continue;
1698                 p->flags |= CHILD_SHOWN;
1699                 gc_boundary(&revs->boundary_commits);
1700                 add_object_array(p, NULL, &revs->boundary_commits);
1701         }
1702
1703         return c;
1704 }