Make revision limiting more robust against occasional bad commit dates
[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 /* How many extra uninteresting commits we want to see.. */
568 #define SLOP 5
569
570 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
571 {
572         /*
573          * No source list at all? We're definitely done..
574          */
575         if (!src)
576                 return 0;
577
578         /*
579          * Does the destination list contain entries with a date
580          * before the source list? Definitely _not_ done.
581          */
582         if (date < src->item->date)
583                 return SLOP;
584
585         /*
586          * Does the source list still have interesting commits in
587          * it? Definitely not done..
588          */
589         if (!everybody_uninteresting(src))
590                 return SLOP;
591
592         /* Ok, we're closing in.. */
593         return slop-1;
594 }
595
596 static int limit_list(struct rev_info *revs)
597 {
598         int slop = SLOP;
599         unsigned long date = ~0ul;
600         struct commit_list *list = revs->commits;
601         struct commit_list *newlist = NULL;
602         struct commit_list **p = &newlist;
603
604         while (list) {
605                 struct commit_list *entry = list;
606                 struct commit *commit = list->item;
607                 struct object *obj = &commit->object;
608                 show_early_output_fn_t show;
609
610                 list = list->next;
611                 free(entry);
612
613                 if (revs->max_age != -1 && (commit->date < revs->max_age))
614                         obj->flags |= UNINTERESTING;
615                 if (add_parents_to_list(revs, commit, &list) < 0)
616                         return -1;
617                 if (obj->flags & UNINTERESTING) {
618                         mark_parents_uninteresting(commit);
619                         if (revs->show_all)
620                                 p = &commit_list_insert(commit, p)->next;
621                         slop = still_interesting(list, date, slop);
622                         if (slop)
623                                 continue;
624                         /* If showing all, add the whole pending list to the end */
625                         if (revs->show_all)
626                                 *p = list;
627                         break;
628                 }
629                 if (revs->min_age != -1 && (commit->date > revs->min_age))
630                         continue;
631                 date = commit->date;
632                 p = &commit_list_insert(commit, p)->next;
633
634                 show = show_early_output;
635                 if (!show)
636                         continue;
637
638                 show(revs, newlist);
639                 show_early_output = NULL;
640         }
641         if (revs->cherry_pick)
642                 cherry_pick_list(newlist, revs);
643
644         revs->commits = newlist;
645         return 0;
646 }
647
648 struct all_refs_cb {
649         int all_flags;
650         int warned_bad_reflog;
651         struct rev_info *all_revs;
652         const char *name_for_errormsg;
653 };
654
655 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
656 {
657         struct all_refs_cb *cb = cb_data;
658         struct object *object = get_reference(cb->all_revs, path, sha1,
659                                               cb->all_flags);
660         add_pending_object(cb->all_revs, object, path);
661         return 0;
662 }
663
664 static void handle_refs(struct rev_info *revs, unsigned flags,
665                 int (*for_each)(each_ref_fn, void *))
666 {
667         struct all_refs_cb cb;
668         cb.all_revs = revs;
669         cb.all_flags = flags;
670         for_each(handle_one_ref, &cb);
671 }
672
673 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
674 {
675         struct all_refs_cb *cb = cb_data;
676         if (!is_null_sha1(sha1)) {
677                 struct object *o = parse_object(sha1);
678                 if (o) {
679                         o->flags |= cb->all_flags;
680                         add_pending_object(cb->all_revs, o, "");
681                 }
682                 else if (!cb->warned_bad_reflog) {
683                         warning("reflog of '%s' references pruned commits",
684                                 cb->name_for_errormsg);
685                         cb->warned_bad_reflog = 1;
686                 }
687         }
688 }
689
690 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
691                 const char *email, unsigned long timestamp, int tz,
692                 const char *message, void *cb_data)
693 {
694         handle_one_reflog_commit(osha1, cb_data);
695         handle_one_reflog_commit(nsha1, cb_data);
696         return 0;
697 }
698
699 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
700 {
701         struct all_refs_cb *cb = cb_data;
702         cb->warned_bad_reflog = 0;
703         cb->name_for_errormsg = path;
704         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
705         return 0;
706 }
707
708 static void handle_reflog(struct rev_info *revs, unsigned flags)
709 {
710         struct all_refs_cb cb;
711         cb.all_revs = revs;
712         cb.all_flags = flags;
713         for_each_reflog(handle_one_reflog, &cb);
714 }
715
716 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
717 {
718         unsigned char sha1[20];
719         struct object *it;
720         struct commit *commit;
721         struct commit_list *parents;
722
723         if (*arg == '^') {
724                 flags ^= UNINTERESTING;
725                 arg++;
726         }
727         if (get_sha1(arg, sha1))
728                 return 0;
729         while (1) {
730                 it = get_reference(revs, arg, sha1, 0);
731                 if (it->type != OBJ_TAG)
732                         break;
733                 if (!((struct tag*)it)->tagged)
734                         return 0;
735                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
736         }
737         if (it->type != OBJ_COMMIT)
738                 return 0;
739         commit = (struct commit *)it;
740         for (parents = commit->parents; parents; parents = parents->next) {
741                 it = &parents->item->object;
742                 it->flags |= flags;
743                 add_pending_object(revs, it, arg);
744         }
745         return 1;
746 }
747
748 void init_revisions(struct rev_info *revs, const char *prefix)
749 {
750         memset(revs, 0, sizeof(*revs));
751
752         revs->abbrev = DEFAULT_ABBREV;
753         revs->ignore_merges = 1;
754         revs->simplify_history = 1;
755         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
756         DIFF_OPT_SET(&revs->pruning, QUIET);
757         revs->pruning.add_remove = file_add_remove;
758         revs->pruning.change = file_change;
759         revs->lifo = 1;
760         revs->dense = 1;
761         revs->prefix = prefix;
762         revs->max_age = -1;
763         revs->min_age = -1;
764         revs->skip_count = -1;
765         revs->max_count = -1;
766
767         revs->commit_format = CMIT_FMT_DEFAULT;
768
769         diff_setup(&revs->diffopt);
770         if (prefix && !revs->diffopt.prefix) {
771                 revs->diffopt.prefix = prefix;
772                 revs->diffopt.prefix_length = strlen(prefix);
773         }
774 }
775
776 static void add_pending_commit_list(struct rev_info *revs,
777                                     struct commit_list *commit_list,
778                                     unsigned int flags)
779 {
780         while (commit_list) {
781                 struct object *object = &commit_list->item->object;
782                 object->flags |= flags;
783                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
784                 commit_list = commit_list->next;
785         }
786 }
787
788 static void prepare_show_merge(struct rev_info *revs)
789 {
790         struct commit_list *bases;
791         struct commit *head, *other;
792         unsigned char sha1[20];
793         const char **prune = NULL;
794         int i, prune_num = 1; /* counting terminating NULL */
795
796         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
797                 die("--merge without HEAD?");
798         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
799                 die("--merge without MERGE_HEAD?");
800         add_pending_object(revs, &head->object, "HEAD");
801         add_pending_object(revs, &other->object, "MERGE_HEAD");
802         bases = get_merge_bases(head, other, 1);
803         add_pending_commit_list(revs, bases, UNINTERESTING);
804         free_commit_list(bases);
805         head->object.flags |= SYMMETRIC_LEFT;
806
807         if (!active_nr)
808                 read_cache();
809         for (i = 0; i < active_nr; i++) {
810                 struct cache_entry *ce = active_cache[i];
811                 if (!ce_stage(ce))
812                         continue;
813                 if (ce_path_match(ce, revs->prune_data)) {
814                         prune_num++;
815                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
816                         prune[prune_num-2] = ce->name;
817                         prune[prune_num-1] = NULL;
818                 }
819                 while ((i+1 < active_nr) &&
820                        ce_same_name(ce, active_cache[i+1]))
821                         i++;
822         }
823         revs->prune_data = prune;
824         revs->limited = 1;
825 }
826
827 int handle_revision_arg(const char *arg, struct rev_info *revs,
828                         int flags,
829                         int cant_be_filename)
830 {
831         unsigned mode;
832         char *dotdot;
833         struct object *object;
834         unsigned char sha1[20];
835         int local_flags;
836
837         dotdot = strstr(arg, "..");
838         if (dotdot) {
839                 unsigned char from_sha1[20];
840                 const char *next = dotdot + 2;
841                 const char *this = arg;
842                 int symmetric = *next == '.';
843                 unsigned int flags_exclude = flags ^ UNINTERESTING;
844
845                 *dotdot = 0;
846                 next += symmetric;
847
848                 if (!*next)
849                         next = "HEAD";
850                 if (dotdot == arg)
851                         this = "HEAD";
852                 if (!get_sha1(this, from_sha1) &&
853                     !get_sha1(next, sha1)) {
854                         struct commit *a, *b;
855                         struct commit_list *exclude;
856
857                         a = lookup_commit_reference(from_sha1);
858                         b = lookup_commit_reference(sha1);
859                         if (!a || !b) {
860                                 die(symmetric ?
861                                     "Invalid symmetric difference expression %s...%s" :
862                                     "Invalid revision range %s..%s",
863                                     arg, next);
864                         }
865
866                         if (!cant_be_filename) {
867                                 *dotdot = '.';
868                                 verify_non_filename(revs->prefix, arg);
869                         }
870
871                         if (symmetric) {
872                                 exclude = get_merge_bases(a, b, 1);
873                                 add_pending_commit_list(revs, exclude,
874                                                         flags_exclude);
875                                 free_commit_list(exclude);
876                                 a->object.flags |= flags | SYMMETRIC_LEFT;
877                         } else
878                                 a->object.flags |= flags_exclude;
879                         b->object.flags |= flags;
880                         add_pending_object(revs, &a->object, this);
881                         add_pending_object(revs, &b->object, next);
882                         return 0;
883                 }
884                 *dotdot = '.';
885         }
886         dotdot = strstr(arg, "^@");
887         if (dotdot && !dotdot[2]) {
888                 *dotdot = 0;
889                 if (add_parents_only(revs, arg, flags))
890                         return 0;
891                 *dotdot = '^';
892         }
893         dotdot = strstr(arg, "^!");
894         if (dotdot && !dotdot[2]) {
895                 *dotdot = 0;
896                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
897                         *dotdot = '^';
898         }
899
900         local_flags = 0;
901         if (*arg == '^') {
902                 local_flags = UNINTERESTING;
903                 arg++;
904         }
905         if (get_sha1_with_mode(arg, sha1, &mode))
906                 return -1;
907         if (!cant_be_filename)
908                 verify_non_filename(revs->prefix, arg);
909         object = get_reference(revs, arg, sha1, flags ^ local_flags);
910         add_pending_object_with_mode(revs, object, arg, mode);
911         return 0;
912 }
913
914 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
915 {
916         if (!revs->grep_filter) {
917                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
918                 opt->status_only = 1;
919                 opt->pattern_tail = &(opt->pattern_list);
920                 opt->regflags = REG_NEWLINE;
921                 revs->grep_filter = opt;
922         }
923         append_grep_pattern(revs->grep_filter, ptn,
924                             "command line", 0, what);
925 }
926
927 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
928 {
929         char *pat;
930         const char *prefix;
931         int patlen, fldlen;
932
933         fldlen = strlen(field);
934         patlen = strlen(pattern);
935         pat = xmalloc(patlen + fldlen + 10);
936         prefix = ".*";
937         if (*pattern == '^') {
938                 prefix = "";
939                 pattern++;
940         }
941         sprintf(pat, "^%s %s%s", field, prefix, pattern);
942         add_grep(revs, pat, GREP_PATTERN_HEAD);
943 }
944
945 static void add_message_grep(struct rev_info *revs, const char *pattern)
946 {
947         add_grep(revs, pattern, GREP_PATTERN_BODY);
948 }
949
950 static void add_ignore_packed(struct rev_info *revs, const char *name)
951 {
952         int num = ++revs->num_ignore_packed;
953
954         revs->ignore_packed = xrealloc(revs->ignore_packed,
955                                        sizeof(const char **) * (num + 1));
956         revs->ignore_packed[num-1] = name;
957         revs->ignore_packed[num] = NULL;
958 }
959
960 /*
961  * Parse revision information, filling in the "rev_info" structure,
962  * and removing the used arguments from the argument list.
963  *
964  * Returns the number of arguments left that weren't recognized
965  * (which are also moved to the head of the argument list)
966  */
967 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
968 {
969         int i, flags, seen_dashdash, show_merge;
970         const char **unrecognized = argv + 1;
971         int left = 1;
972         int all_match = 0;
973         int regflags = 0;
974         int fixed = 0;
975
976         /* First, search for "--" */
977         seen_dashdash = 0;
978         for (i = 1; i < argc; i++) {
979                 const char *arg = argv[i];
980                 if (strcmp(arg, "--"))
981                         continue;
982                 argv[i] = NULL;
983                 argc = i;
984                 if (argv[i + 1])
985                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
986                 seen_dashdash = 1;
987                 break;
988         }
989
990         flags = show_merge = 0;
991         for (i = 1; i < argc; i++) {
992                 const char *arg = argv[i];
993                 if (*arg == '-') {
994                         int opts;
995                         if (!prefixcmp(arg, "--max-count=")) {
996                                 revs->max_count = atoi(arg + 12);
997                                 continue;
998                         }
999                         if (!prefixcmp(arg, "--skip=")) {
1000                                 revs->skip_count = atoi(arg + 7);
1001                                 continue;
1002                         }
1003                         /* accept -<digit>, like traditional "head" */
1004                         if ((*arg == '-') && isdigit(arg[1])) {
1005                                 revs->max_count = atoi(arg + 1);
1006                                 continue;
1007                         }
1008                         if (!strcmp(arg, "-n")) {
1009                                 if (argc <= i + 1)
1010                                         die("-n requires an argument");
1011                                 revs->max_count = atoi(argv[++i]);
1012                                 continue;
1013                         }
1014                         if (!prefixcmp(arg, "-n")) {
1015                                 revs->max_count = atoi(arg + 2);
1016                                 continue;
1017                         }
1018                         if (!prefixcmp(arg, "--max-age=")) {
1019                                 revs->max_age = atoi(arg + 10);
1020                                 continue;
1021                         }
1022                         if (!prefixcmp(arg, "--since=")) {
1023                                 revs->max_age = approxidate(arg + 8);
1024                                 continue;
1025                         }
1026                         if (!prefixcmp(arg, "--after=")) {
1027                                 revs->max_age = approxidate(arg + 8);
1028                                 continue;
1029                         }
1030                         if (!prefixcmp(arg, "--min-age=")) {
1031                                 revs->min_age = atoi(arg + 10);
1032                                 continue;
1033                         }
1034                         if (!prefixcmp(arg, "--before=")) {
1035                                 revs->min_age = approxidate(arg + 9);
1036                                 continue;
1037                         }
1038                         if (!prefixcmp(arg, "--until=")) {
1039                                 revs->min_age = approxidate(arg + 8);
1040                                 continue;
1041                         }
1042                         if (!strcmp(arg, "--all")) {
1043                                 handle_refs(revs, flags, for_each_ref);
1044                                 continue;
1045                         }
1046                         if (!strcmp(arg, "--branches")) {
1047                                 handle_refs(revs, flags, for_each_branch_ref);
1048                                 continue;
1049                         }
1050                         if (!strcmp(arg, "--tags")) {
1051                                 handle_refs(revs, flags, for_each_tag_ref);
1052                                 continue;
1053                         }
1054                         if (!strcmp(arg, "--remotes")) {
1055                                 handle_refs(revs, flags, for_each_remote_ref);
1056                                 continue;
1057                         }
1058                         if (!strcmp(arg, "--first-parent")) {
1059                                 revs->first_parent_only = 1;
1060                                 continue;
1061                         }
1062                         if (!strcmp(arg, "--reflog")) {
1063                                 handle_reflog(revs, flags);
1064                                 continue;
1065                         }
1066                         if (!strcmp(arg, "-g") ||
1067                                         !strcmp(arg, "--walk-reflogs")) {
1068                                 init_reflog_walk(&revs->reflog_info);
1069                                 continue;
1070                         }
1071                         if (!strcmp(arg, "--not")) {
1072                                 flags ^= UNINTERESTING;
1073                                 continue;
1074                         }
1075                         if (!strcmp(arg, "--default")) {
1076                                 if (++i >= argc)
1077                                         die("bad --default argument");
1078                                 def = argv[i];
1079                                 continue;
1080                         }
1081                         if (!strcmp(arg, "--merge")) {
1082                                 show_merge = 1;
1083                                 continue;
1084                         }
1085                         if (!strcmp(arg, "--topo-order")) {
1086                                 revs->topo_order = 1;
1087                                 continue;
1088                         }
1089                         if (!strcmp(arg, "--date-order")) {
1090                                 revs->lifo = 0;
1091                                 revs->topo_order = 1;
1092                                 continue;
1093                         }
1094                         if (!prefixcmp(arg, "--early-output")) {
1095                                 int count = 100;
1096                                 switch (arg[14]) {
1097                                 case '=':
1098                                         count = atoi(arg+15);
1099                                         /* Fallthrough */
1100                                 case 0:
1101                                         revs->topo_order = 1;
1102                                         revs->early_output = count;
1103                                         continue;
1104                                 }
1105                         }
1106                         if (!strcmp(arg, "--parents")) {
1107                                 revs->parents = 1;
1108                                 continue;
1109                         }
1110                         if (!strcmp(arg, "--dense")) {
1111                                 revs->dense = 1;
1112                                 continue;
1113                         }
1114                         if (!strcmp(arg, "--sparse")) {
1115                                 revs->dense = 0;
1116                                 continue;
1117                         }
1118                         if (!strcmp(arg, "--show-all")) {
1119                                 revs->show_all = 1;
1120                                 continue;
1121                         }
1122                         if (!strcmp(arg, "--remove-empty")) {
1123                                 revs->remove_empty_trees = 1;
1124                                 continue;
1125                         }
1126                         if (!strcmp(arg, "--no-merges")) {
1127                                 revs->no_merges = 1;
1128                                 continue;
1129                         }
1130                         if (!strcmp(arg, "--boundary")) {
1131                                 revs->boundary = 1;
1132                                 continue;
1133                         }
1134                         if (!strcmp(arg, "--left-right")) {
1135                                 revs->left_right = 1;
1136                                 continue;
1137                         }
1138                         if (!strcmp(arg, "--cherry-pick")) {
1139                                 revs->cherry_pick = 1;
1140                                 revs->limited = 1;
1141                                 continue;
1142                         }
1143                         if (!strcmp(arg, "--objects")) {
1144                                 revs->tag_objects = 1;
1145                                 revs->tree_objects = 1;
1146                                 revs->blob_objects = 1;
1147                                 continue;
1148                         }
1149                         if (!strcmp(arg, "--objects-edge")) {
1150                                 revs->tag_objects = 1;
1151                                 revs->tree_objects = 1;
1152                                 revs->blob_objects = 1;
1153                                 revs->edge_hint = 1;
1154                                 continue;
1155                         }
1156                         if (!strcmp(arg, "--unpacked")) {
1157                                 revs->unpacked = 1;
1158                                 free(revs->ignore_packed);
1159                                 revs->ignore_packed = NULL;
1160                                 revs->num_ignore_packed = 0;
1161                                 continue;
1162                         }
1163                         if (!prefixcmp(arg, "--unpacked=")) {
1164                                 revs->unpacked = 1;
1165                                 add_ignore_packed(revs, arg+11);
1166                                 continue;
1167                         }
1168                         if (!strcmp(arg, "-r")) {
1169                                 revs->diff = 1;
1170                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1171                                 continue;
1172                         }
1173                         if (!strcmp(arg, "-t")) {
1174                                 revs->diff = 1;
1175                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1176                                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1177                                 continue;
1178                         }
1179                         if (!strcmp(arg, "-m")) {
1180                                 revs->ignore_merges = 0;
1181                                 continue;
1182                         }
1183                         if (!strcmp(arg, "-c")) {
1184                                 revs->diff = 1;
1185                                 revs->dense_combined_merges = 0;
1186                                 revs->combine_merges = 1;
1187                                 continue;
1188                         }
1189                         if (!strcmp(arg, "--cc")) {
1190                                 revs->diff = 1;
1191                                 revs->dense_combined_merges = 1;
1192                                 revs->combine_merges = 1;
1193                                 continue;
1194                         }
1195                         if (!strcmp(arg, "-v")) {
1196                                 revs->verbose_header = 1;
1197                                 continue;
1198                         }
1199                         if (!prefixcmp(arg, "--pretty")) {
1200                                 revs->verbose_header = 1;
1201                                 revs->commit_format = get_commit_format(arg+8);
1202                                 continue;
1203                         }
1204                         if (!strcmp(arg, "--root")) {
1205                                 revs->show_root_diff = 1;
1206                                 continue;
1207                         }
1208                         if (!strcmp(arg, "--no-commit-id")) {
1209                                 revs->no_commit_id = 1;
1210                                 continue;
1211                         }
1212                         if (!strcmp(arg, "--always")) {
1213                                 revs->always_show_header = 1;
1214                                 continue;
1215                         }
1216                         if (!strcmp(arg, "--no-abbrev")) {
1217                                 revs->abbrev = 0;
1218                                 continue;
1219                         }
1220                         if (!strcmp(arg, "--abbrev")) {
1221                                 revs->abbrev = DEFAULT_ABBREV;
1222                                 continue;
1223                         }
1224                         if (!prefixcmp(arg, "--abbrev=")) {
1225                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1226                                 if (revs->abbrev < MINIMUM_ABBREV)
1227                                         revs->abbrev = MINIMUM_ABBREV;
1228                                 else if (revs->abbrev > 40)
1229                                         revs->abbrev = 40;
1230                                 continue;
1231                         }
1232                         if (!strcmp(arg, "--abbrev-commit")) {
1233                                 revs->abbrev_commit = 1;
1234                                 continue;
1235                         }
1236                         if (!strcmp(arg, "--full-diff")) {
1237                                 revs->diff = 1;
1238                                 revs->full_diff = 1;
1239                                 continue;
1240                         }
1241                         if (!strcmp(arg, "--full-history")) {
1242                                 revs->simplify_history = 0;
1243                                 continue;
1244                         }
1245                         if (!strcmp(arg, "--relative-date")) {
1246                                 revs->date_mode = DATE_RELATIVE;
1247                                 continue;
1248                         }
1249                         if (!strncmp(arg, "--date=", 7)) {
1250                                 revs->date_mode = parse_date_format(arg + 7);
1251                                 continue;
1252                         }
1253                         if (!strcmp(arg, "--log-size")) {
1254                                 revs->show_log_size = 1;
1255                                 continue;
1256                         }
1257
1258                         /*
1259                          * Grepping the commit log
1260                          */
1261                         if (!prefixcmp(arg, "--author=")) {
1262                                 add_header_grep(revs, "author", arg+9);
1263                                 continue;
1264                         }
1265                         if (!prefixcmp(arg, "--committer=")) {
1266                                 add_header_grep(revs, "committer", arg+12);
1267                                 continue;
1268                         }
1269                         if (!prefixcmp(arg, "--grep=")) {
1270                                 add_message_grep(revs, arg+7);
1271                                 continue;
1272                         }
1273                         if (!strcmp(arg, "--extended-regexp") ||
1274                             !strcmp(arg, "-E")) {
1275                                 regflags |= REG_EXTENDED;
1276                                 continue;
1277                         }
1278                         if (!strcmp(arg, "--regexp-ignore-case") ||
1279                             !strcmp(arg, "-i")) {
1280                                 regflags |= REG_ICASE;
1281                                 continue;
1282                         }
1283                         if (!strcmp(arg, "--fixed-strings") ||
1284                             !strcmp(arg, "-F")) {
1285                                 fixed = 1;
1286                                 continue;
1287                         }
1288                         if (!strcmp(arg, "--all-match")) {
1289                                 all_match = 1;
1290                                 continue;
1291                         }
1292                         if (!prefixcmp(arg, "--encoding=")) {
1293                                 arg += 11;
1294                                 if (strcmp(arg, "none"))
1295                                         git_log_output_encoding = xstrdup(arg);
1296                                 else
1297                                         git_log_output_encoding = "";
1298                                 continue;
1299                         }
1300                         if (!strcmp(arg, "--reverse")) {
1301                                 revs->reverse ^= 1;
1302                                 continue;
1303                         }
1304                         if (!strcmp(arg, "--no-walk")) {
1305                                 revs->no_walk = 1;
1306                                 continue;
1307                         }
1308                         if (!strcmp(arg, "--do-walk")) {
1309                                 revs->no_walk = 0;
1310                                 continue;
1311                         }
1312
1313                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
1314                         if (opts > 0) {
1315                                 i += opts - 1;
1316                                 continue;
1317                         }
1318                         *unrecognized++ = arg;
1319                         left++;
1320                         continue;
1321                 }
1322
1323                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1324                         int j;
1325                         if (seen_dashdash || *arg == '^')
1326                                 die("bad revision '%s'", arg);
1327
1328                         /* If we didn't have a "--":
1329                          * (1) all filenames must exist;
1330                          * (2) all rev-args must not be interpretable
1331                          *     as a valid filename.
1332                          * but the latter we have checked in the main loop.
1333                          */
1334                         for (j = i; j < argc; j++)
1335                                 verify_filename(revs->prefix, argv[j]);
1336
1337                         revs->prune_data = get_pathspec(revs->prefix,
1338                                                         argv + i);
1339                         break;
1340                 }
1341         }
1342
1343         if (revs->grep_filter) {
1344                 revs->grep_filter->regflags |= regflags;
1345                 revs->grep_filter->fixed = fixed;
1346         }
1347
1348         if (show_merge)
1349                 prepare_show_merge(revs);
1350         if (def && !revs->pending.nr) {
1351                 unsigned char sha1[20];
1352                 struct object *object;
1353                 unsigned mode;
1354                 if (get_sha1_with_mode(def, sha1, &mode))
1355                         die("bad default revision '%s'", def);
1356                 object = get_reference(revs, def, sha1, 0);
1357                 add_pending_object_with_mode(revs, object, def, mode);
1358         }
1359
1360         /* Did the user ask for any diff output? Run the diff! */
1361         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1362                 revs->diff = 1;
1363
1364         /* Pickaxe, diff-filter and rename following need diffs */
1365         if (revs->diffopt.pickaxe ||
1366             revs->diffopt.filter ||
1367             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1368                 revs->diff = 1;
1369
1370         if (revs->topo_order)
1371                 revs->limited = 1;
1372
1373         if (revs->prune_data) {
1374                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1375                 /* Can't prune commits with rename following: the paths change.. */
1376                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1377                         revs->prune = 1;
1378                 if (!revs->full_diff)
1379                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1380         }
1381         if (revs->combine_merges) {
1382                 revs->ignore_merges = 0;
1383                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1384                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1385         }
1386         revs->diffopt.abbrev = revs->abbrev;
1387         if (diff_setup_done(&revs->diffopt) < 0)
1388                 die("diff_setup_done failed");
1389
1390         if (revs->grep_filter) {
1391                 revs->grep_filter->all_match = all_match;
1392                 compile_grep_patterns(revs->grep_filter);
1393         }
1394
1395         if (revs->reverse && revs->reflog_info)
1396                 die("cannot combine --reverse with --walk-reflogs");
1397
1398         return left;
1399 }
1400
1401 int prepare_revision_walk(struct rev_info *revs)
1402 {
1403         int nr = revs->pending.nr;
1404         struct object_array_entry *e, *list;
1405
1406         e = list = revs->pending.objects;
1407         revs->pending.nr = 0;
1408         revs->pending.alloc = 0;
1409         revs->pending.objects = NULL;
1410         while (--nr >= 0) {
1411                 struct commit *commit = handle_commit(revs, e->item, e->name);
1412                 if (commit) {
1413                         if (!(commit->object.flags & SEEN)) {
1414                                 commit->object.flags |= SEEN;
1415                                 insert_by_date(commit, &revs->commits);
1416                         }
1417                 }
1418                 e++;
1419         }
1420         free(list);
1421
1422         if (revs->no_walk)
1423                 return 0;
1424         if (revs->limited)
1425                 if (limit_list(revs) < 0)
1426                         return -1;
1427         if (revs->topo_order)
1428                 sort_in_topological_order(&revs->commits, revs->lifo);
1429         return 0;
1430 }
1431
1432 enum rewrite_result {
1433         rewrite_one_ok,
1434         rewrite_one_noparents,
1435         rewrite_one_error,
1436 };
1437
1438 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1439 {
1440         for (;;) {
1441                 struct commit *p = *pp;
1442                 if (!revs->limited)
1443                         if (add_parents_to_list(revs, p, &revs->commits) < 0)
1444                                 return rewrite_one_error;
1445                 if (p->parents && p->parents->next)
1446                         return rewrite_one_ok;
1447                 if (p->object.flags & UNINTERESTING)
1448                         return rewrite_one_ok;
1449                 if (!(p->object.flags & TREESAME))
1450                         return rewrite_one_ok;
1451                 if (!p->parents)
1452                         return rewrite_one_noparents;
1453                 *pp = p->parents->item;
1454         }
1455 }
1456
1457 static void remove_duplicate_parents(struct commit *commit)
1458 {
1459         struct commit_list **pp, *p;
1460
1461         /* Examine existing parents while marking ones we have seen... */
1462         pp = &commit->parents;
1463         while ((p = *pp) != NULL) {
1464                 struct commit *parent = p->item;
1465                 if (parent->object.flags & TMP_MARK) {
1466                         *pp = p->next;
1467                         continue;
1468                 }
1469                 parent->object.flags |= TMP_MARK;
1470                 pp = &p->next;
1471         }
1472         /* ... and clear the temporary mark */
1473         for (p = commit->parents; p; p = p->next)
1474                 p->item->object.flags &= ~TMP_MARK;
1475 }
1476
1477 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1478 {
1479         struct commit_list **pp = &commit->parents;
1480         while (*pp) {
1481                 struct commit_list *parent = *pp;
1482                 switch (rewrite_one(revs, &parent->item)) {
1483                 case rewrite_one_ok:
1484                         break;
1485                 case rewrite_one_noparents:
1486                         *pp = parent->next;
1487                         continue;
1488                 case rewrite_one_error:
1489                         return -1;
1490                 }
1491                 pp = &parent->next;
1492         }
1493         remove_duplicate_parents(commit);
1494         return 0;
1495 }
1496
1497 static int commit_match(struct commit *commit, struct rev_info *opt)
1498 {
1499         if (!opt->grep_filter)
1500                 return 1;
1501         return grep_buffer(opt->grep_filter,
1502                            NULL, /* we say nothing, not even filename */
1503                            commit->buffer, strlen(commit->buffer));
1504 }
1505
1506 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1507 {
1508         if (commit->object.flags & SHOWN)
1509                 return commit_ignore;
1510         if (revs->unpacked && has_sha1_pack(commit->object.sha1, revs->ignore_packed))
1511                 return commit_ignore;
1512         if (revs->show_all)
1513                 return commit_show;
1514         if (commit->object.flags & UNINTERESTING)
1515                 return commit_ignore;
1516         if (revs->min_age != -1 && (commit->date > revs->min_age))
1517                 return commit_ignore;
1518         if (revs->no_merges && commit->parents && commit->parents->next)
1519                 return commit_ignore;
1520         if (!commit_match(commit, revs))
1521                 return commit_ignore;
1522         if (revs->prune && revs->dense) {
1523                 /* Commit without changes? */
1524                 if (commit->object.flags & TREESAME) {
1525                         /* drop merges unless we want parenthood */
1526                         if (!revs->parents)
1527                                 return commit_ignore;
1528                         /* non-merge - always ignore it */
1529                         if (!commit->parents || !commit->parents->next)
1530                                 return commit_ignore;
1531                 }
1532                 if (revs->parents && rewrite_parents(revs, commit) < 0)
1533                         return commit_error;
1534         }
1535         return commit_show;
1536 }
1537
1538 static struct commit *get_revision_1(struct rev_info *revs)
1539 {
1540         if (!revs->commits)
1541                 return NULL;
1542
1543         do {
1544                 struct commit_list *entry = revs->commits;
1545                 struct commit *commit = entry->item;
1546
1547                 revs->commits = entry->next;
1548                 free(entry);
1549
1550                 if (revs->reflog_info)
1551                         fake_reflog_parent(revs->reflog_info, commit);
1552
1553                 /*
1554                  * If we haven't done the list limiting, we need to look at
1555                  * the parents here. We also need to do the date-based limiting
1556                  * that we'd otherwise have done in limit_list().
1557                  */
1558                 if (!revs->limited) {
1559                         if (revs->max_age != -1 &&
1560                             (commit->date < revs->max_age))
1561                                 continue;
1562                         if (add_parents_to_list(revs, commit, &revs->commits) < 0)
1563                                 return NULL;
1564                 }
1565
1566                 switch (simplify_commit(revs, commit)) {
1567                 case commit_ignore:
1568                         continue;
1569                 case commit_error:
1570                         return NULL;
1571                 default:
1572                         return commit;
1573                 }
1574         } while (revs->commits);
1575         return NULL;
1576 }
1577
1578 static void gc_boundary(struct object_array *array)
1579 {
1580         unsigned nr = array->nr;
1581         unsigned alloc = array->alloc;
1582         struct object_array_entry *objects = array->objects;
1583
1584         if (alloc <= nr) {
1585                 unsigned i, j;
1586                 for (i = j = 0; i < nr; i++) {
1587                         if (objects[i].item->flags & SHOWN)
1588                                 continue;
1589                         if (i != j)
1590                                 objects[j] = objects[i];
1591                         j++;
1592                 }
1593                 for (i = j; i < nr; i++)
1594                         objects[i].item = NULL;
1595                 array->nr = j;
1596         }
1597 }
1598
1599 struct commit *get_revision(struct rev_info *revs)
1600 {
1601         struct commit *c = NULL;
1602         struct commit_list *l;
1603
1604         if (revs->boundary == 2) {
1605                 unsigned i;
1606                 struct object_array *array = &revs->boundary_commits;
1607                 struct object_array_entry *objects = array->objects;
1608                 for (i = 0; i < array->nr; i++) {
1609                         c = (struct commit *)(objects[i].item);
1610                         if (!c)
1611                                 continue;
1612                         if (!(c->object.flags & CHILD_SHOWN))
1613                                 continue;
1614                         if (!(c->object.flags & SHOWN))
1615                                 break;
1616                 }
1617                 if (array->nr <= i)
1618                         return NULL;
1619
1620                 c->object.flags |= SHOWN | BOUNDARY;
1621                 return c;
1622         }
1623
1624         if (revs->reverse) {
1625                 int limit = -1;
1626
1627                 if (0 <= revs->max_count) {
1628                         limit = revs->max_count;
1629                         if (0 < revs->skip_count)
1630                                 limit += revs->skip_count;
1631                 }
1632                 l = NULL;
1633                 while ((c = get_revision_1(revs))) {
1634                         commit_list_insert(c, &l);
1635                         if ((0 < limit) && !--limit)
1636                                 break;
1637                 }
1638                 revs->commits = l;
1639                 revs->reverse = 0;
1640                 revs->max_count = -1;
1641                 c = NULL;
1642         }
1643
1644         /*
1645          * Now pick up what they want to give us
1646          */
1647         c = get_revision_1(revs);
1648         if (c) {
1649                 while (0 < revs->skip_count) {
1650                         revs->skip_count--;
1651                         c = get_revision_1(revs);
1652                         if (!c)
1653                                 break;
1654                 }
1655         }
1656
1657         /*
1658          * Check the max_count.
1659          */
1660         switch (revs->max_count) {
1661         case -1:
1662                 break;
1663         case 0:
1664                 c = NULL;
1665                 break;
1666         default:
1667                 revs->max_count--;
1668         }
1669
1670         if (c)
1671                 c->object.flags |= SHOWN;
1672
1673         if (!revs->boundary) {
1674                 return c;
1675         }
1676
1677         if (!c) {
1678                 /*
1679                  * get_revision_1() runs out the commits, and
1680                  * we are done computing the boundaries.
1681                  * switch to boundary commits output mode.
1682                  */
1683                 revs->boundary = 2;
1684                 return get_revision(revs);
1685         }
1686
1687         /*
1688          * boundary commits are the commits that are parents of the
1689          * ones we got from get_revision_1() but they themselves are
1690          * not returned from get_revision_1().  Before returning
1691          * 'c', we need to mark its parents that they could be boundaries.
1692          */
1693
1694         for (l = c->parents; l; l = l->next) {
1695                 struct object *p;
1696                 p = &(l->item->object);
1697                 if (p->flags & (CHILD_SHOWN | SHOWN))
1698                         continue;
1699                 p->flags |= CHILD_SHOWN;
1700                 gc_boundary(&revs->boundary_commits);
1701                 add_object_array(p, NULL, &revs->boundary_commits);
1702         }
1703
1704         return c;
1705 }