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