Merge branch 'js/remote'
[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         int add, rest;
419
420         if (commit->object.flags & ADDED)
421                 return 0;
422         commit->object.flags |= ADDED;
423
424         /*
425          * If the commit is uninteresting, don't try to
426          * prune parents - we want the maximal uninteresting
427          * set.
428          *
429          * Normally we haven't parsed the parent
430          * yet, so we won't have a parent of a parent
431          * here. However, it may turn out that we've
432          * reached this commit some other way (where it
433          * wasn't uninteresting), in which case we need
434          * to mark its parents recursively too..
435          */
436         if (commit->object.flags & UNINTERESTING) {
437                 while (parent) {
438                         struct commit *p = parent->item;
439                         parent = parent->next;
440                         if (parse_commit(p) < 0)
441                                 return -1;
442                         p->object.flags |= UNINTERESTING;
443                         if (p->parents)
444                                 mark_parents_uninteresting(p);
445                         if (p->object.flags & SEEN)
446                                 continue;
447                         p->object.flags |= SEEN;
448                         insert_by_date(p, list);
449                 }
450                 return 0;
451         }
452
453         /*
454          * Ok, the commit wasn't uninteresting. Try to
455          * simplify the commit history and find the parent
456          * that has no differences in the path set if one exists.
457          */
458         try_to_simplify_commit(revs, commit);
459
460         if (revs->no_walk)
461                 return 0;
462
463         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
464
465         rest = !revs->first_parent_only;
466         for (parent = commit->parents, add = 1; parent; add = rest) {
467                 struct commit *p = parent->item;
468
469                 parent = parent->next;
470                 if (parse_commit(p) < 0)
471                         return -1;
472                 p->object.flags |= left_flag;
473                 if (p->object.flags & SEEN)
474                         continue;
475                 p->object.flags |= SEEN;
476                 if (add)
477                         insert_by_date(p, list);
478         }
479         return 0;
480 }
481
482 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
483 {
484         struct commit_list *p;
485         int left_count = 0, right_count = 0;
486         int left_first;
487         struct patch_ids ids;
488
489         /* First count the commits on the left and on the right */
490         for (p = list; p; p = p->next) {
491                 struct commit *commit = p->item;
492                 unsigned flags = commit->object.flags;
493                 if (flags & BOUNDARY)
494                         ;
495                 else if (flags & SYMMETRIC_LEFT)
496                         left_count++;
497                 else
498                         right_count++;
499         }
500
501         left_first = left_count < right_count;
502         init_patch_ids(&ids);
503         if (revs->diffopt.nr_paths) {
504                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
505                 ids.diffopts.paths = revs->diffopt.paths;
506                 ids.diffopts.pathlens = revs->diffopt.pathlens;
507         }
508
509         /* Compute patch-ids for one side */
510         for (p = list; p; p = p->next) {
511                 struct commit *commit = p->item;
512                 unsigned flags = commit->object.flags;
513
514                 if (flags & BOUNDARY)
515                         continue;
516                 /*
517                  * If we have fewer left, left_first is set and we omit
518                  * commits on the right branch in this loop.  If we have
519                  * fewer right, we skip the left ones.
520                  */
521                 if (left_first != !!(flags & SYMMETRIC_LEFT))
522                         continue;
523                 commit->util = add_commit_patch_id(commit, &ids);
524         }
525
526         /* Check the other side */
527         for (p = list; p; p = p->next) {
528                 struct commit *commit = p->item;
529                 struct patch_id *id;
530                 unsigned flags = commit->object.flags;
531
532                 if (flags & BOUNDARY)
533                         continue;
534                 /*
535                  * If we have fewer left, left_first is set and we omit
536                  * commits on the left branch in this loop.
537                  */
538                 if (left_first == !!(flags & SYMMETRIC_LEFT))
539                         continue;
540
541                 /*
542                  * Have we seen the same patch id?
543                  */
544                 id = has_commit_patch_id(commit, &ids);
545                 if (!id)
546                         continue;
547                 id->seen = 1;
548                 commit->object.flags |= SHOWN;
549         }
550
551         /* Now check the original side for seen ones */
552         for (p = list; p; p = p->next) {
553                 struct commit *commit = p->item;
554                 struct patch_id *ent;
555
556                 ent = commit->util;
557                 if (!ent)
558                         continue;
559                 if (ent->seen)
560                         commit->object.flags |= SHOWN;
561                 commit->util = NULL;
562         }
563
564         free_patch_ids(&ids);
565 }
566
567 static void add_to_list(struct commit_list **p, struct commit *commit, struct commit_list *n)
568 {
569         p = &commit_list_insert(commit, p)->next;
570         *p = n;
571 }
572
573 static int limit_list(struct rev_info *revs)
574 {
575         struct commit_list *list = revs->commits;
576         struct commit_list *newlist = NULL;
577         struct commit_list **p = &newlist;
578
579         while (list) {
580                 struct commit_list *entry = list;
581                 struct commit *commit = list->item;
582                 struct object *obj = &commit->object;
583                 show_early_output_fn_t show;
584
585                 list = list->next;
586                 free(entry);
587
588                 if (revs->max_age != -1 && (commit->date < revs->max_age))
589                         obj->flags |= UNINTERESTING;
590                 if (add_parents_to_list(revs, commit, &list) < 0)
591                         return -1;
592                 if (obj->flags & UNINTERESTING) {
593                         mark_parents_uninteresting(commit);
594                         if (everybody_uninteresting(list)) {
595                                 if (revs->show_all)
596                                         add_to_list(p, commit, list);
597                                 break;
598                         }
599                         if (!revs->show_all)
600                                 continue;
601                 }
602                 if (revs->min_age != -1 && (commit->date > revs->min_age))
603                         continue;
604                 p = &commit_list_insert(commit, p)->next;
605
606                 show = show_early_output;
607                 if (!show)
608                         continue;
609
610                 show(revs, newlist);
611                 show_early_output = NULL;
612         }
613         if (revs->cherry_pick)
614                 cherry_pick_list(newlist, revs);
615
616         revs->commits = newlist;
617         return 0;
618 }
619
620 struct all_refs_cb {
621         int all_flags;
622         int warned_bad_reflog;
623         struct rev_info *all_revs;
624         const char *name_for_errormsg;
625 };
626
627 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
628 {
629         struct all_refs_cb *cb = cb_data;
630         struct object *object = get_reference(cb->all_revs, path, sha1,
631                                               cb->all_flags);
632         add_pending_object(cb->all_revs, object, path);
633         return 0;
634 }
635
636 static void handle_refs(struct rev_info *revs, unsigned flags,
637                 int (*for_each)(each_ref_fn, void *))
638 {
639         struct all_refs_cb cb;
640         cb.all_revs = revs;
641         cb.all_flags = flags;
642         for_each(handle_one_ref, &cb);
643 }
644
645 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
646 {
647         struct all_refs_cb *cb = cb_data;
648         if (!is_null_sha1(sha1)) {
649                 struct object *o = parse_object(sha1);
650                 if (o) {
651                         o->flags |= cb->all_flags;
652                         add_pending_object(cb->all_revs, o, "");
653                 }
654                 else if (!cb->warned_bad_reflog) {
655                         warning("reflog of '%s' references pruned commits",
656                                 cb->name_for_errormsg);
657                         cb->warned_bad_reflog = 1;
658                 }
659         }
660 }
661
662 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
663                 const char *email, unsigned long timestamp, int tz,
664                 const char *message, void *cb_data)
665 {
666         handle_one_reflog_commit(osha1, cb_data);
667         handle_one_reflog_commit(nsha1, cb_data);
668         return 0;
669 }
670
671 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
672 {
673         struct all_refs_cb *cb = cb_data;
674         cb->warned_bad_reflog = 0;
675         cb->name_for_errormsg = path;
676         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
677         return 0;
678 }
679
680 static void handle_reflog(struct rev_info *revs, unsigned flags)
681 {
682         struct all_refs_cb cb;
683         cb.all_revs = revs;
684         cb.all_flags = flags;
685         for_each_reflog(handle_one_reflog, &cb);
686 }
687
688 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
689 {
690         unsigned char sha1[20];
691         struct object *it;
692         struct commit *commit;
693         struct commit_list *parents;
694
695         if (*arg == '^') {
696                 flags ^= UNINTERESTING;
697                 arg++;
698         }
699         if (get_sha1(arg, sha1))
700                 return 0;
701         while (1) {
702                 it = get_reference(revs, arg, sha1, 0);
703                 if (it->type != OBJ_TAG)
704                         break;
705                 if (!((struct tag*)it)->tagged)
706                         return 0;
707                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
708         }
709         if (it->type != OBJ_COMMIT)
710                 return 0;
711         commit = (struct commit *)it;
712         for (parents = commit->parents; parents; parents = parents->next) {
713                 it = &parents->item->object;
714                 it->flags |= flags;
715                 add_pending_object(revs, it, arg);
716         }
717         return 1;
718 }
719
720 void init_revisions(struct rev_info *revs, const char *prefix)
721 {
722         memset(revs, 0, sizeof(*revs));
723
724         revs->abbrev = DEFAULT_ABBREV;
725         revs->ignore_merges = 1;
726         revs->simplify_history = 1;
727         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
728         DIFF_OPT_SET(&revs->pruning, QUIET);
729         revs->pruning.add_remove = file_add_remove;
730         revs->pruning.change = file_change;
731         revs->lifo = 1;
732         revs->dense = 1;
733         revs->prefix = prefix;
734         revs->max_age = -1;
735         revs->min_age = -1;
736         revs->skip_count = -1;
737         revs->max_count = -1;
738
739         revs->commit_format = CMIT_FMT_DEFAULT;
740
741         diff_setup(&revs->diffopt);
742         if (prefix && !revs->diffopt.prefix) {
743                 revs->diffopt.prefix = prefix;
744                 revs->diffopt.prefix_length = strlen(prefix);
745         }
746 }
747
748 static void add_pending_commit_list(struct rev_info *revs,
749                                     struct commit_list *commit_list,
750                                     unsigned int flags)
751 {
752         while (commit_list) {
753                 struct object *object = &commit_list->item->object;
754                 object->flags |= flags;
755                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
756                 commit_list = commit_list->next;
757         }
758 }
759
760 static void prepare_show_merge(struct rev_info *revs)
761 {
762         struct commit_list *bases;
763         struct commit *head, *other;
764         unsigned char sha1[20];
765         const char **prune = NULL;
766         int i, prune_num = 1; /* counting terminating NULL */
767
768         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
769                 die("--merge without HEAD?");
770         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
771                 die("--merge without MERGE_HEAD?");
772         add_pending_object(revs, &head->object, "HEAD");
773         add_pending_object(revs, &other->object, "MERGE_HEAD");
774         bases = get_merge_bases(head, other, 1);
775         add_pending_commit_list(revs, bases, UNINTERESTING);
776         free_commit_list(bases);
777         head->object.flags |= SYMMETRIC_LEFT;
778
779         if (!active_nr)
780                 read_cache();
781         for (i = 0; i < active_nr; i++) {
782                 struct cache_entry *ce = active_cache[i];
783                 if (!ce_stage(ce))
784                         continue;
785                 if (ce_path_match(ce, revs->prune_data)) {
786                         prune_num++;
787                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
788                         prune[prune_num-2] = ce->name;
789                         prune[prune_num-1] = NULL;
790                 }
791                 while ((i+1 < active_nr) &&
792                        ce_same_name(ce, active_cache[i+1]))
793                         i++;
794         }
795         revs->prune_data = prune;
796         revs->limited = 1;
797 }
798
799 int handle_revision_arg(const char *arg, struct rev_info *revs,
800                         int flags,
801                         int cant_be_filename)
802 {
803         unsigned mode;
804         char *dotdot;
805         struct object *object;
806         unsigned char sha1[20];
807         int local_flags;
808
809         dotdot = strstr(arg, "..");
810         if (dotdot) {
811                 unsigned char from_sha1[20];
812                 const char *next = dotdot + 2;
813                 const char *this = arg;
814                 int symmetric = *next == '.';
815                 unsigned int flags_exclude = flags ^ UNINTERESTING;
816
817                 *dotdot = 0;
818                 next += symmetric;
819
820                 if (!*next)
821                         next = "HEAD";
822                 if (dotdot == arg)
823                         this = "HEAD";
824                 if (!get_sha1(this, from_sha1) &&
825                     !get_sha1(next, sha1)) {
826                         struct commit *a, *b;
827                         struct commit_list *exclude;
828
829                         a = lookup_commit_reference(from_sha1);
830                         b = lookup_commit_reference(sha1);
831                         if (!a || !b) {
832                                 die(symmetric ?
833                                     "Invalid symmetric difference expression %s...%s" :
834                                     "Invalid revision range %s..%s",
835                                     arg, next);
836                         }
837
838                         if (!cant_be_filename) {
839                                 *dotdot = '.';
840                                 verify_non_filename(revs->prefix, arg);
841                         }
842
843                         if (symmetric) {
844                                 exclude = get_merge_bases(a, b, 1);
845                                 add_pending_commit_list(revs, exclude,
846                                                         flags_exclude);
847                                 free_commit_list(exclude);
848                                 a->object.flags |= flags | SYMMETRIC_LEFT;
849                         } else
850                                 a->object.flags |= flags_exclude;
851                         b->object.flags |= flags;
852                         add_pending_object(revs, &a->object, this);
853                         add_pending_object(revs, &b->object, next);
854                         return 0;
855                 }
856                 *dotdot = '.';
857         }
858         dotdot = strstr(arg, "^@");
859         if (dotdot && !dotdot[2]) {
860                 *dotdot = 0;
861                 if (add_parents_only(revs, arg, flags))
862                         return 0;
863                 *dotdot = '^';
864         }
865         dotdot = strstr(arg, "^!");
866         if (dotdot && !dotdot[2]) {
867                 *dotdot = 0;
868                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
869                         *dotdot = '^';
870         }
871
872         local_flags = 0;
873         if (*arg == '^') {
874                 local_flags = UNINTERESTING;
875                 arg++;
876         }
877         if (get_sha1_with_mode(arg, sha1, &mode))
878                 return -1;
879         if (!cant_be_filename)
880                 verify_non_filename(revs->prefix, arg);
881         object = get_reference(revs, arg, sha1, flags ^ local_flags);
882         add_pending_object_with_mode(revs, object, arg, mode);
883         return 0;
884 }
885
886 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
887 {
888         if (!revs->grep_filter) {
889                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
890                 opt->status_only = 1;
891                 opt->pattern_tail = &(opt->pattern_list);
892                 opt->regflags = REG_NEWLINE;
893                 revs->grep_filter = opt;
894         }
895         append_grep_pattern(revs->grep_filter, ptn,
896                             "command line", 0, what);
897 }
898
899 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
900 {
901         char *pat;
902         const char *prefix;
903         int patlen, fldlen;
904
905         fldlen = strlen(field);
906         patlen = strlen(pattern);
907         pat = xmalloc(patlen + fldlen + 10);
908         prefix = ".*";
909         if (*pattern == '^') {
910                 prefix = "";
911                 pattern++;
912         }
913         sprintf(pat, "^%s %s%s", field, prefix, pattern);
914         add_grep(revs, pat, GREP_PATTERN_HEAD);
915 }
916
917 static void add_message_grep(struct rev_info *revs, const char *pattern)
918 {
919         add_grep(revs, pattern, GREP_PATTERN_BODY);
920 }
921
922 static void add_ignore_packed(struct rev_info *revs, const char *name)
923 {
924         int num = ++revs->num_ignore_packed;
925
926         revs->ignore_packed = xrealloc(revs->ignore_packed,
927                                        sizeof(const char **) * (num + 1));
928         revs->ignore_packed[num-1] = name;
929         revs->ignore_packed[num] = NULL;
930 }
931
932 /*
933  * Parse revision information, filling in the "rev_info" structure,
934  * and removing the used arguments from the argument list.
935  *
936  * Returns the number of arguments left that weren't recognized
937  * (which are also moved to the head of the argument list)
938  */
939 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
940 {
941         int i, flags, seen_dashdash, show_merge;
942         const char **unrecognized = argv + 1;
943         int left = 1;
944         int all_match = 0;
945         int regflags = 0;
946         int fixed = 0;
947
948         /* First, search for "--" */
949         seen_dashdash = 0;
950         for (i = 1; i < argc; i++) {
951                 const char *arg = argv[i];
952                 if (strcmp(arg, "--"))
953                         continue;
954                 argv[i] = NULL;
955                 argc = i;
956                 if (argv[i + 1])
957                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
958                 seen_dashdash = 1;
959                 break;
960         }
961
962         flags = show_merge = 0;
963         for (i = 1; i < argc; i++) {
964                 const char *arg = argv[i];
965                 if (*arg == '-') {
966                         int opts;
967                         if (!prefixcmp(arg, "--max-count=")) {
968                                 revs->max_count = atoi(arg + 12);
969                                 continue;
970                         }
971                         if (!prefixcmp(arg, "--skip=")) {
972                                 revs->skip_count = atoi(arg + 7);
973                                 continue;
974                         }
975                         /* accept -<digit>, like traditional "head" */
976                         if ((*arg == '-') && isdigit(arg[1])) {
977                                 revs->max_count = atoi(arg + 1);
978                                 continue;
979                         }
980                         if (!strcmp(arg, "-n")) {
981                                 if (argc <= i + 1)
982                                         die("-n requires an argument");
983                                 revs->max_count = atoi(argv[++i]);
984                                 continue;
985                         }
986                         if (!prefixcmp(arg, "-n")) {
987                                 revs->max_count = atoi(arg + 2);
988                                 continue;
989                         }
990                         if (!prefixcmp(arg, "--max-age=")) {
991                                 revs->max_age = atoi(arg + 10);
992                                 continue;
993                         }
994                         if (!prefixcmp(arg, "--since=")) {
995                                 revs->max_age = approxidate(arg + 8);
996                                 continue;
997                         }
998                         if (!prefixcmp(arg, "--after=")) {
999                                 revs->max_age = approxidate(arg + 8);
1000                                 continue;
1001                         }
1002                         if (!prefixcmp(arg, "--min-age=")) {
1003                                 revs->min_age = atoi(arg + 10);
1004                                 continue;
1005                         }
1006                         if (!prefixcmp(arg, "--before=")) {
1007                                 revs->min_age = approxidate(arg + 9);
1008                                 continue;
1009                         }
1010                         if (!prefixcmp(arg, "--until=")) {
1011                                 revs->min_age = approxidate(arg + 8);
1012                                 continue;
1013                         }
1014                         if (!strcmp(arg, "--all")) {
1015                                 handle_refs(revs, flags, for_each_ref);
1016                                 continue;
1017                         }
1018                         if (!strcmp(arg, "--branches")) {
1019                                 handle_refs(revs, flags, for_each_branch_ref);
1020                                 continue;
1021                         }
1022                         if (!strcmp(arg, "--tags")) {
1023                                 handle_refs(revs, flags, for_each_tag_ref);
1024                                 continue;
1025                         }
1026                         if (!strcmp(arg, "--remotes")) {
1027                                 handle_refs(revs, flags, for_each_remote_ref);
1028                                 continue;
1029                         }
1030                         if (!strcmp(arg, "--first-parent")) {
1031                                 revs->first_parent_only = 1;
1032                                 continue;
1033                         }
1034                         if (!strcmp(arg, "--reflog")) {
1035                                 handle_reflog(revs, flags);
1036                                 continue;
1037                         }
1038                         if (!strcmp(arg, "-g") ||
1039                                         !strcmp(arg, "--walk-reflogs")) {
1040                                 init_reflog_walk(&revs->reflog_info);
1041                                 continue;
1042                         }
1043                         if (!strcmp(arg, "--not")) {
1044                                 flags ^= UNINTERESTING;
1045                                 continue;
1046                         }
1047                         if (!strcmp(arg, "--default")) {
1048                                 if (++i >= argc)
1049                                         die("bad --default argument");
1050                                 def = argv[i];
1051                                 continue;
1052                         }
1053                         if (!strcmp(arg, "--merge")) {
1054                                 show_merge = 1;
1055                                 continue;
1056                         }
1057                         if (!strcmp(arg, "--topo-order")) {
1058                                 revs->topo_order = 1;
1059                                 continue;
1060                         }
1061                         if (!strcmp(arg, "--date-order")) {
1062                                 revs->lifo = 0;
1063                                 revs->topo_order = 1;
1064                                 continue;
1065                         }
1066                         if (!prefixcmp(arg, "--early-output")) {
1067                                 int count = 100;
1068                                 switch (arg[14]) {
1069                                 case '=':
1070                                         count = atoi(arg+15);
1071                                         /* Fallthrough */
1072                                 case 0:
1073                                         revs->topo_order = 1;
1074                                         revs->early_output = count;
1075                                         continue;
1076                                 }
1077                         }
1078                         if (!strcmp(arg, "--parents")) {
1079                                 revs->parents = 1;
1080                                 continue;
1081                         }
1082                         if (!strcmp(arg, "--dense")) {
1083                                 revs->dense = 1;
1084                                 continue;
1085                         }
1086                         if (!strcmp(arg, "--sparse")) {
1087                                 revs->dense = 0;
1088                                 continue;
1089                         }
1090                         if (!strcmp(arg, "--show-all")) {
1091                                 revs->show_all = 1;
1092                                 continue;
1093                         }
1094                         if (!strcmp(arg, "--remove-empty")) {
1095                                 revs->remove_empty_trees = 1;
1096                                 continue;
1097                         }
1098                         if (!strcmp(arg, "--no-merges")) {
1099                                 revs->no_merges = 1;
1100                                 continue;
1101                         }
1102                         if (!strcmp(arg, "--boundary")) {
1103                                 revs->boundary = 1;
1104                                 continue;
1105                         }
1106                         if (!strcmp(arg, "--left-right")) {
1107                                 revs->left_right = 1;
1108                                 continue;
1109                         }
1110                         if (!strcmp(arg, "--cherry-pick")) {
1111                                 revs->cherry_pick = 1;
1112                                 revs->limited = 1;
1113                                 continue;
1114                         }
1115                         if (!strcmp(arg, "--objects")) {
1116                                 revs->tag_objects = 1;
1117                                 revs->tree_objects = 1;
1118                                 revs->blob_objects = 1;
1119                                 continue;
1120                         }
1121                         if (!strcmp(arg, "--objects-edge")) {
1122                                 revs->tag_objects = 1;
1123                                 revs->tree_objects = 1;
1124                                 revs->blob_objects = 1;
1125                                 revs->edge_hint = 1;
1126                                 continue;
1127                         }
1128                         if (!strcmp(arg, "--unpacked")) {
1129                                 revs->unpacked = 1;
1130                                 free(revs->ignore_packed);
1131                                 revs->ignore_packed = NULL;
1132                                 revs->num_ignore_packed = 0;
1133                                 continue;
1134                         }
1135                         if (!prefixcmp(arg, "--unpacked=")) {
1136                                 revs->unpacked = 1;
1137                                 add_ignore_packed(revs, arg+11);
1138                                 continue;
1139                         }
1140                         if (!strcmp(arg, "-r")) {
1141                                 revs->diff = 1;
1142                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1143                                 continue;
1144                         }
1145                         if (!strcmp(arg, "-t")) {
1146                                 revs->diff = 1;
1147                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1148                                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1149                                 continue;
1150                         }
1151                         if (!strcmp(arg, "-m")) {
1152                                 revs->ignore_merges = 0;
1153                                 continue;
1154                         }
1155                         if (!strcmp(arg, "-c")) {
1156                                 revs->diff = 1;
1157                                 revs->dense_combined_merges = 0;
1158                                 revs->combine_merges = 1;
1159                                 continue;
1160                         }
1161                         if (!strcmp(arg, "--cc")) {
1162                                 revs->diff = 1;
1163                                 revs->dense_combined_merges = 1;
1164                                 revs->combine_merges = 1;
1165                                 continue;
1166                         }
1167                         if (!strcmp(arg, "-v")) {
1168                                 revs->verbose_header = 1;
1169                                 continue;
1170                         }
1171                         if (!prefixcmp(arg, "--pretty")) {
1172                                 revs->verbose_header = 1;
1173                                 revs->commit_format = get_commit_format(arg+8);
1174                                 continue;
1175                         }
1176                         if (!strcmp(arg, "--root")) {
1177                                 revs->show_root_diff = 1;
1178                                 continue;
1179                         }
1180                         if (!strcmp(arg, "--no-commit-id")) {
1181                                 revs->no_commit_id = 1;
1182                                 continue;
1183                         }
1184                         if (!strcmp(arg, "--always")) {
1185                                 revs->always_show_header = 1;
1186                                 continue;
1187                         }
1188                         if (!strcmp(arg, "--no-abbrev")) {
1189                                 revs->abbrev = 0;
1190                                 continue;
1191                         }
1192                         if (!strcmp(arg, "--abbrev")) {
1193                                 revs->abbrev = DEFAULT_ABBREV;
1194                                 continue;
1195                         }
1196                         if (!prefixcmp(arg, "--abbrev=")) {
1197                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1198                                 if (revs->abbrev < MINIMUM_ABBREV)
1199                                         revs->abbrev = MINIMUM_ABBREV;
1200                                 else if (revs->abbrev > 40)
1201                                         revs->abbrev = 40;
1202                                 continue;
1203                         }
1204                         if (!strcmp(arg, "--abbrev-commit")) {
1205                                 revs->abbrev_commit = 1;
1206                                 continue;
1207                         }
1208                         if (!strcmp(arg, "--full-diff")) {
1209                                 revs->diff = 1;
1210                                 revs->full_diff = 1;
1211                                 continue;
1212                         }
1213                         if (!strcmp(arg, "--full-history")) {
1214                                 revs->simplify_history = 0;
1215                                 continue;
1216                         }
1217                         if (!strcmp(arg, "--relative-date")) {
1218                                 revs->date_mode = DATE_RELATIVE;
1219                                 continue;
1220                         }
1221                         if (!strncmp(arg, "--date=", 7)) {
1222                                 revs->date_mode = parse_date_format(arg + 7);
1223                                 continue;
1224                         }
1225                         if (!strcmp(arg, "--log-size")) {
1226                                 revs->show_log_size = 1;
1227                                 continue;
1228                         }
1229
1230                         /*
1231                          * Grepping the commit log
1232                          */
1233                         if (!prefixcmp(arg, "--author=")) {
1234                                 add_header_grep(revs, "author", arg+9);
1235                                 continue;
1236                         }
1237                         if (!prefixcmp(arg, "--committer=")) {
1238                                 add_header_grep(revs, "committer", arg+12);
1239                                 continue;
1240                         }
1241                         if (!prefixcmp(arg, "--grep=")) {
1242                                 add_message_grep(revs, arg+7);
1243                                 continue;
1244                         }
1245                         if (!strcmp(arg, "--extended-regexp") ||
1246                             !strcmp(arg, "-E")) {
1247                                 regflags |= REG_EXTENDED;
1248                                 continue;
1249                         }
1250                         if (!strcmp(arg, "--regexp-ignore-case") ||
1251                             !strcmp(arg, "-i")) {
1252                                 regflags |= REG_ICASE;
1253                                 continue;
1254                         }
1255                         if (!strcmp(arg, "--fixed-strings") ||
1256                             !strcmp(arg, "-F")) {
1257                                 fixed = 1;
1258                                 continue;
1259                         }
1260                         if (!strcmp(arg, "--all-match")) {
1261                                 all_match = 1;
1262                                 continue;
1263                         }
1264                         if (!prefixcmp(arg, "--encoding=")) {
1265                                 arg += 11;
1266                                 if (strcmp(arg, "none"))
1267                                         git_log_output_encoding = xstrdup(arg);
1268                                 else
1269                                         git_log_output_encoding = "";
1270                                 continue;
1271                         }
1272                         if (!strcmp(arg, "--reverse")) {
1273                                 revs->reverse ^= 1;
1274                                 continue;
1275                         }
1276                         if (!strcmp(arg, "--no-walk")) {
1277                                 revs->no_walk = 1;
1278                                 continue;
1279                         }
1280                         if (!strcmp(arg, "--do-walk")) {
1281                                 revs->no_walk = 0;
1282                                 continue;
1283                         }
1284
1285                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
1286                         if (opts > 0) {
1287                                 i += opts - 1;
1288                                 continue;
1289                         }
1290                         *unrecognized++ = arg;
1291                         left++;
1292                         continue;
1293                 }
1294
1295                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1296                         int j;
1297                         if (seen_dashdash || *arg == '^')
1298                                 die("bad revision '%s'", arg);
1299
1300                         /* If we didn't have a "--":
1301                          * (1) all filenames must exist;
1302                          * (2) all rev-args must not be interpretable
1303                          *     as a valid filename.
1304                          * but the latter we have checked in the main loop.
1305                          */
1306                         for (j = i; j < argc; j++)
1307                                 verify_filename(revs->prefix, argv[j]);
1308
1309                         revs->prune_data = get_pathspec(revs->prefix,
1310                                                         argv + i);
1311                         break;
1312                 }
1313         }
1314
1315         if (revs->grep_filter) {
1316                 revs->grep_filter->regflags |= regflags;
1317                 revs->grep_filter->fixed = fixed;
1318         }
1319
1320         if (show_merge)
1321                 prepare_show_merge(revs);
1322         if (def && !revs->pending.nr) {
1323                 unsigned char sha1[20];
1324                 struct object *object;
1325                 unsigned mode;
1326                 if (get_sha1_with_mode(def, sha1, &mode))
1327                         die("bad default revision '%s'", def);
1328                 object = get_reference(revs, def, sha1, 0);
1329                 add_pending_object_with_mode(revs, object, def, mode);
1330         }
1331
1332         /* Did the user ask for any diff output? Run the diff! */
1333         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1334                 revs->diff = 1;
1335
1336         /* Pickaxe, diff-filter and rename following need diffs */
1337         if (revs->diffopt.pickaxe ||
1338             revs->diffopt.filter ||
1339             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1340                 revs->diff = 1;
1341
1342         if (revs->topo_order)
1343                 revs->limited = 1;
1344
1345         if (revs->prune_data) {
1346                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1347                 /* Can't prune commits with rename following: the paths change.. */
1348                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1349                         revs->prune = 1;
1350                 if (!revs->full_diff)
1351                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1352         }
1353         if (revs->combine_merges) {
1354                 revs->ignore_merges = 0;
1355                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1356                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1357         }
1358         revs->diffopt.abbrev = revs->abbrev;
1359         if (diff_setup_done(&revs->diffopt) < 0)
1360                 die("diff_setup_done failed");
1361
1362         if (revs->grep_filter) {
1363                 revs->grep_filter->all_match = all_match;
1364                 compile_grep_patterns(revs->grep_filter);
1365         }
1366
1367         if (revs->reverse && revs->reflog_info)
1368                 die("cannot combine --reverse with --walk-reflogs");
1369
1370         return left;
1371 }
1372
1373 int prepare_revision_walk(struct rev_info *revs)
1374 {
1375         int nr = revs->pending.nr;
1376         struct object_array_entry *e, *list;
1377
1378         e = list = revs->pending.objects;
1379         revs->pending.nr = 0;
1380         revs->pending.alloc = 0;
1381         revs->pending.objects = NULL;
1382         while (--nr >= 0) {
1383                 struct commit *commit = handle_commit(revs, e->item, e->name);
1384                 if (commit) {
1385                         if (!(commit->object.flags & SEEN)) {
1386                                 commit->object.flags |= SEEN;
1387                                 insert_by_date(commit, &revs->commits);
1388                         }
1389                 }
1390                 e++;
1391         }
1392         free(list);
1393
1394         if (revs->no_walk)
1395                 return 0;
1396         if (revs->limited)
1397                 if (limit_list(revs) < 0)
1398                         return -1;
1399         if (revs->topo_order)
1400                 sort_in_topological_order(&revs->commits, revs->lifo);
1401         return 0;
1402 }
1403
1404 enum rewrite_result {
1405         rewrite_one_ok,
1406         rewrite_one_noparents,
1407         rewrite_one_error,
1408 };
1409
1410 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1411 {
1412         for (;;) {
1413                 struct commit *p = *pp;
1414                 if (!revs->limited)
1415                         if (add_parents_to_list(revs, p, &revs->commits) < 0)
1416                                 return rewrite_one_error;
1417                 if (p->parents && p->parents->next)
1418                         return rewrite_one_ok;
1419                 if (p->object.flags & UNINTERESTING)
1420                         return rewrite_one_ok;
1421                 if (!(p->object.flags & TREESAME))
1422                         return rewrite_one_ok;
1423                 if (!p->parents)
1424                         return rewrite_one_noparents;
1425                 *pp = p->parents->item;
1426         }
1427 }
1428
1429 static void remove_duplicate_parents(struct commit *commit)
1430 {
1431         struct commit_list **pp, *p;
1432
1433         /* Examine existing parents while marking ones we have seen... */
1434         pp = &commit->parents;
1435         while ((p = *pp) != NULL) {
1436                 struct commit *parent = p->item;
1437                 if (parent->object.flags & TMP_MARK) {
1438                         *pp = p->next;
1439                         continue;
1440                 }
1441                 parent->object.flags |= TMP_MARK;
1442                 pp = &p->next;
1443         }
1444         /* ... and clear the temporary mark */
1445         for (p = commit->parents; p; p = p->next)
1446                 p->item->object.flags &= ~TMP_MARK;
1447 }
1448
1449 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1450 {
1451         struct commit_list **pp = &commit->parents;
1452         while (*pp) {
1453                 struct commit_list *parent = *pp;
1454                 switch (rewrite_one(revs, &parent->item)) {
1455                 case rewrite_one_ok:
1456                         break;
1457                 case rewrite_one_noparents:
1458                         *pp = parent->next;
1459                         continue;
1460                 case rewrite_one_error:
1461                         return -1;
1462                 }
1463                 pp = &parent->next;
1464         }
1465         remove_duplicate_parents(commit);
1466         return 0;
1467 }
1468
1469 static int commit_match(struct commit *commit, struct rev_info *opt)
1470 {
1471         if (!opt->grep_filter)
1472                 return 1;
1473         return grep_buffer(opt->grep_filter,
1474                            NULL, /* we say nothing, not even filename */
1475                            commit->buffer, strlen(commit->buffer));
1476 }
1477
1478 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1479 {
1480         if (commit->object.flags & SHOWN)
1481                 return commit_ignore;
1482         if (revs->unpacked && has_sha1_pack(commit->object.sha1, revs->ignore_packed))
1483                 return commit_ignore;
1484         if (revs->show_all)
1485                 return commit_show;
1486         if (commit->object.flags & UNINTERESTING)
1487                 return commit_ignore;
1488         if (revs->min_age != -1 && (commit->date > revs->min_age))
1489                 return commit_ignore;
1490         if (revs->no_merges && commit->parents && commit->parents->next)
1491                 return commit_ignore;
1492         if (!commit_match(commit, revs))
1493                 return commit_ignore;
1494         if (revs->prune && revs->dense) {
1495                 /* Commit without changes? */
1496                 if (commit->object.flags & TREESAME) {
1497                         /* drop merges unless we want parenthood */
1498                         if (!revs->parents)
1499                                 return commit_ignore;
1500                         /* non-merge - always ignore it */
1501                         if (!commit->parents || !commit->parents->next)
1502                                 return commit_ignore;
1503                 }
1504                 if (revs->parents && rewrite_parents(revs, commit) < 0)
1505                         return commit_error;
1506         }
1507         return commit_show;
1508 }
1509
1510 static struct commit *get_revision_1(struct rev_info *revs)
1511 {
1512         if (!revs->commits)
1513                 return NULL;
1514
1515         do {
1516                 struct commit_list *entry = revs->commits;
1517                 struct commit *commit = entry->item;
1518
1519                 revs->commits = entry->next;
1520                 free(entry);
1521
1522                 if (revs->reflog_info)
1523                         fake_reflog_parent(revs->reflog_info, commit);
1524
1525                 /*
1526                  * If we haven't done the list limiting, we need to look at
1527                  * the parents here. We also need to do the date-based limiting
1528                  * that we'd otherwise have done in limit_list().
1529                  */
1530                 if (!revs->limited) {
1531                         if (revs->max_age != -1 &&
1532                             (commit->date < revs->max_age))
1533                                 continue;
1534                         if (add_parents_to_list(revs, commit, &revs->commits) < 0)
1535                                 return NULL;
1536                 }
1537
1538                 switch (simplify_commit(revs, commit)) {
1539                 case commit_ignore:
1540                         continue;
1541                 case commit_error:
1542                         return NULL;
1543                 default:
1544                         return commit;
1545                 }
1546         } while (revs->commits);
1547         return NULL;
1548 }
1549
1550 static void gc_boundary(struct object_array *array)
1551 {
1552         unsigned nr = array->nr;
1553         unsigned alloc = array->alloc;
1554         struct object_array_entry *objects = array->objects;
1555
1556         if (alloc <= nr) {
1557                 unsigned i, j;
1558                 for (i = j = 0; i < nr; i++) {
1559                         if (objects[i].item->flags & SHOWN)
1560                                 continue;
1561                         if (i != j)
1562                                 objects[j] = objects[i];
1563                         j++;
1564                 }
1565                 for (i = j; i < nr; i++)
1566                         objects[i].item = NULL;
1567                 array->nr = j;
1568         }
1569 }
1570
1571 struct commit *get_revision(struct rev_info *revs)
1572 {
1573         struct commit *c = NULL;
1574         struct commit_list *l;
1575
1576         if (revs->boundary == 2) {
1577                 unsigned i;
1578                 struct object_array *array = &revs->boundary_commits;
1579                 struct object_array_entry *objects = array->objects;
1580                 for (i = 0; i < array->nr; i++) {
1581                         c = (struct commit *)(objects[i].item);
1582                         if (!c)
1583                                 continue;
1584                         if (!(c->object.flags & CHILD_SHOWN))
1585                                 continue;
1586                         if (!(c->object.flags & SHOWN))
1587                                 break;
1588                 }
1589                 if (array->nr <= i)
1590                         return NULL;
1591
1592                 c->object.flags |= SHOWN | BOUNDARY;
1593                 return c;
1594         }
1595
1596         if (revs->reverse) {
1597                 int limit = -1;
1598
1599                 if (0 <= revs->max_count) {
1600                         limit = revs->max_count;
1601                         if (0 < revs->skip_count)
1602                                 limit += revs->skip_count;
1603                 }
1604                 l = NULL;
1605                 while ((c = get_revision_1(revs))) {
1606                         commit_list_insert(c, &l);
1607                         if ((0 < limit) && !--limit)
1608                                 break;
1609                 }
1610                 revs->commits = l;
1611                 revs->reverse = 0;
1612                 revs->max_count = -1;
1613                 c = NULL;
1614         }
1615
1616         /*
1617          * Now pick up what they want to give us
1618          */
1619         c = get_revision_1(revs);
1620         if (c) {
1621                 while (0 < revs->skip_count) {
1622                         revs->skip_count--;
1623                         c = get_revision_1(revs);
1624                         if (!c)
1625                                 break;
1626                 }
1627         }
1628
1629         /*
1630          * Check the max_count.
1631          */
1632         switch (revs->max_count) {
1633         case -1:
1634                 break;
1635         case 0:
1636                 c = NULL;
1637                 break;
1638         default:
1639                 revs->max_count--;
1640         }
1641
1642         if (c)
1643                 c->object.flags |= SHOWN;
1644
1645         if (!revs->boundary) {
1646                 return c;
1647         }
1648
1649         if (!c) {
1650                 /*
1651                  * get_revision_1() runs out the commits, and
1652                  * we are done computing the boundaries.
1653                  * switch to boundary commits output mode.
1654                  */
1655                 revs->boundary = 2;
1656                 return get_revision(revs);
1657         }
1658
1659         /*
1660          * boundary commits are the commits that are parents of the
1661          * ones we got from get_revision_1() but they themselves are
1662          * not returned from get_revision_1().  Before returning
1663          * 'c', we need to mark its parents that they could be boundaries.
1664          */
1665
1666         for (l = c->parents; l; l = l->next) {
1667                 struct object *p;
1668                 p = &(l->item->object);
1669                 if (p->flags & (CHILD_SHOWN | SHOWN))
1670                         continue;
1671                 p->flags |= CHILD_SHOWN;
1672                 gc_boundary(&revs->boundary_commits);
1673                 add_object_array(p, NULL, &revs->boundary_commits);
1674         }
1675
1676         return c;
1677 }