Merge branch 'ms/non-ascii-ticks' into maint
[git] / revision.c
1 #include "cache.h"
2 #include "tag.h"
3 #include "blob.h"
4 #include "tree.h"
5 #include "commit.h"
6 #include "diff.h"
7 #include "refs.h"
8 #include "revision.h"
9 #include "graph.h"
10 #include "grep.h"
11 #include "reflog-walk.h"
12 #include "patch-ids.h"
13 #include "decorate.h"
14 #include "log-tree.h"
15 #include "string-list.h"
16 #include "line-log.h"
17 #include "mailmap.h"
18 #include "commit-slab.h"
19 #include "dir.h"
20 #include "cache-tree.h"
21 #include "bisect.h"
22 #include "packfile.h"
23 #include "worktree.h"
24 #include "argv-array.h"
25
26 volatile show_early_output_fn_t show_early_output;
27
28 static const char *term_bad;
29 static const char *term_good;
30
31 void show_object_with_name(FILE *out, struct object *obj, const char *name)
32 {
33         const char *p;
34
35         fprintf(out, "%s ", oid_to_hex(&obj->oid));
36         for (p = name; *p && *p != '\n'; p++)
37                 fputc(*p, out);
38         fputc('\n', out);
39 }
40
41 static void mark_blob_uninteresting(struct blob *blob)
42 {
43         if (!blob)
44                 return;
45         if (blob->object.flags & UNINTERESTING)
46                 return;
47         blob->object.flags |= UNINTERESTING;
48 }
49
50 static void mark_tree_contents_uninteresting(struct tree *tree)
51 {
52         struct tree_desc desc;
53         struct name_entry entry;
54         struct object *obj = &tree->object;
55
56         if (!has_object_file(&obj->oid))
57                 return;
58         if (parse_tree(tree) < 0)
59                 die("bad tree %s", oid_to_hex(&obj->oid));
60
61         init_tree_desc(&desc, tree->buffer, tree->size);
62         while (tree_entry(&desc, &entry)) {
63                 switch (object_type(entry.mode)) {
64                 case OBJ_TREE:
65                         mark_tree_uninteresting(lookup_tree(entry.oid));
66                         break;
67                 case OBJ_BLOB:
68                         mark_blob_uninteresting(lookup_blob(entry.oid));
69                         break;
70                 default:
71                         /* Subproject commit - not in this repository */
72                         break;
73                 }
74         }
75
76         /*
77          * We don't care about the tree any more
78          * after it has been marked uninteresting.
79          */
80         free_tree_buffer(tree);
81 }
82
83 void mark_tree_uninteresting(struct tree *tree)
84 {
85         struct object *obj;
86
87         if (!tree)
88                 return;
89
90         obj = &tree->object;
91         if (obj->flags & UNINTERESTING)
92                 return;
93         obj->flags |= UNINTERESTING;
94         mark_tree_contents_uninteresting(tree);
95 }
96
97 void mark_parents_uninteresting(struct commit *commit)
98 {
99         struct commit_list *parents = NULL, *l;
100
101         for (l = commit->parents; l; l = l->next)
102                 commit_list_insert(l->item, &parents);
103
104         while (parents) {
105                 struct commit *commit = pop_commit(&parents);
106
107                 while (commit) {
108                         /*
109                          * A missing commit is ok iff its parent is marked
110                          * uninteresting.
111                          *
112                          * We just mark such a thing parsed, so that when
113                          * it is popped next time around, we won't be trying
114                          * to parse it and get an error.
115                          */
116                         if (!has_object_file(&commit->object.oid))
117                                 commit->object.parsed = 1;
118
119                         if (commit->object.flags & UNINTERESTING)
120                                 break;
121
122                         commit->object.flags |= UNINTERESTING;
123
124                         /*
125                          * Normally we haven't parsed the parent
126                          * yet, so we won't have a parent of a parent
127                          * here. However, it may turn out that we've
128                          * reached this commit some other way (where it
129                          * wasn't uninteresting), in which case we need
130                          * to mark its parents recursively too..
131                          */
132                         if (!commit->parents)
133                                 break;
134
135                         for (l = commit->parents->next; l; l = l->next)
136                                 commit_list_insert(l->item, &parents);
137                         commit = commit->parents->item;
138                 }
139         }
140 }
141
142 static void add_pending_object_with_path(struct rev_info *revs,
143                                          struct object *obj,
144                                          const char *name, unsigned mode,
145                                          const char *path)
146 {
147         if (!obj)
148                 return;
149         if (revs->no_walk && (obj->flags & UNINTERESTING))
150                 revs->no_walk = 0;
151         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
152                 struct strbuf buf = STRBUF_INIT;
153                 int len = interpret_branch_name(name, 0, &buf, 0);
154
155                 if (0 < len && name[len] && buf.len)
156                         strbuf_addstr(&buf, name + len);
157                 add_reflog_for_walk(revs->reflog_info,
158                                     (struct commit *)obj,
159                                     buf.buf[0] ? buf.buf: name);
160                 strbuf_release(&buf);
161                 return; /* do not add the commit itself */
162         }
163         add_object_array_with_path(obj, name, &revs->pending, mode, path);
164 }
165
166 static void add_pending_object_with_mode(struct rev_info *revs,
167                                          struct object *obj,
168                                          const char *name, unsigned mode)
169 {
170         add_pending_object_with_path(revs, obj, name, mode, NULL);
171 }
172
173 void add_pending_object(struct rev_info *revs,
174                         struct object *obj, const char *name)
175 {
176         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
177 }
178
179 void add_head_to_pending(struct rev_info *revs)
180 {
181         struct object_id oid;
182         struct object *obj;
183         if (get_oid("HEAD", &oid))
184                 return;
185         obj = parse_object(&oid);
186         if (!obj)
187                 return;
188         add_pending_object(revs, obj, "HEAD");
189 }
190
191 static struct object *get_reference(struct rev_info *revs, const char *name,
192                                     const struct object_id *oid,
193                                     unsigned int flags)
194 {
195         struct object *object;
196
197         object = parse_object(oid);
198         if (!object) {
199                 if (revs->ignore_missing)
200                         return object;
201                 die("bad object %s", name);
202         }
203         object->flags |= flags;
204         return object;
205 }
206
207 void add_pending_oid(struct rev_info *revs, const char *name,
208                       const struct object_id *oid, unsigned int flags)
209 {
210         struct object *object = get_reference(revs, name, oid, flags);
211         add_pending_object(revs, object, name);
212 }
213
214 static struct commit *handle_commit(struct rev_info *revs,
215                                     struct object_array_entry *entry)
216 {
217         struct object *object = entry->item;
218         const char *name = entry->name;
219         const char *path = entry->path;
220         unsigned int mode = entry->mode;
221         unsigned long flags = object->flags;
222
223         /*
224          * Tag object? Look what it points to..
225          */
226         while (object->type == OBJ_TAG) {
227                 struct tag *tag = (struct tag *) object;
228                 if (revs->tag_objects && !(flags & UNINTERESTING))
229                         add_pending_object(revs, object, tag->tag);
230                 if (!tag->tagged)
231                         die("bad tag");
232                 object = parse_object(&tag->tagged->oid);
233                 if (!object) {
234                         if (revs->ignore_missing_links || (flags & UNINTERESTING))
235                                 return NULL;
236                         die("bad object %s", oid_to_hex(&tag->tagged->oid));
237                 }
238                 object->flags |= flags;
239                 /*
240                  * We'll handle the tagged object by looping or dropping
241                  * through to the non-tag handlers below. Do not
242                  * propagate path data from the tag's pending entry.
243                  */
244                 path = NULL;
245                 mode = 0;
246         }
247
248         /*
249          * Commit object? Just return it, we'll do all the complex
250          * reachability crud.
251          */
252         if (object->type == OBJ_COMMIT) {
253                 struct commit *commit = (struct commit *)object;
254                 if (parse_commit(commit) < 0)
255                         die("unable to parse commit %s", name);
256                 if (flags & UNINTERESTING) {
257                         mark_parents_uninteresting(commit);
258                         revs->limited = 1;
259                 }
260                 if (revs->show_source && !commit->util)
261                         commit->util = xstrdup(name);
262                 return commit;
263         }
264
265         /*
266          * Tree object? Either mark it uninteresting, or add it
267          * to the list of objects to look at later..
268          */
269         if (object->type == OBJ_TREE) {
270                 struct tree *tree = (struct tree *)object;
271                 if (!revs->tree_objects)
272                         return NULL;
273                 if (flags & UNINTERESTING) {
274                         mark_tree_contents_uninteresting(tree);
275                         return NULL;
276                 }
277                 add_pending_object_with_path(revs, object, name, mode, path);
278                 return NULL;
279         }
280
281         /*
282          * Blob object? You know the drill by now..
283          */
284         if (object->type == OBJ_BLOB) {
285                 if (!revs->blob_objects)
286                         return NULL;
287                 if (flags & UNINTERESTING)
288                         return NULL;
289                 add_pending_object_with_path(revs, object, name, mode, path);
290                 return NULL;
291         }
292         die("%s is unknown object", name);
293 }
294
295 static int everybody_uninteresting(struct commit_list *orig,
296                                    struct commit **interesting_cache)
297 {
298         struct commit_list *list = orig;
299
300         if (*interesting_cache) {
301                 struct commit *commit = *interesting_cache;
302                 if (!(commit->object.flags & UNINTERESTING))
303                         return 0;
304         }
305
306         while (list) {
307                 struct commit *commit = list->item;
308                 list = list->next;
309                 if (commit->object.flags & UNINTERESTING)
310                         continue;
311
312                 *interesting_cache = commit;
313                 return 0;
314         }
315         return 1;
316 }
317
318 /*
319  * A definition of "relevant" commit that we can use to simplify limited graphs
320  * by eliminating side branches.
321  *
322  * A "relevant" commit is one that is !UNINTERESTING (ie we are including it
323  * in our list), or that is a specified BOTTOM commit. Then after computing
324  * a limited list, during processing we can generally ignore boundary merges
325  * coming from outside the graph, (ie from irrelevant parents), and treat
326  * those merges as if they were single-parent. TREESAME is defined to consider
327  * only relevant parents, if any. If we are TREESAME to our on-graph parents,
328  * we don't care if we were !TREESAME to non-graph parents.
329  *
330  * Treating bottom commits as relevant ensures that a limited graph's
331  * connection to the actual bottom commit is not viewed as a side branch, but
332  * treated as part of the graph. For example:
333  *
334  *   ....Z...A---X---o---o---B
335  *        .     /
336  *         W---Y
337  *
338  * When computing "A..B", the A-X connection is at least as important as
339  * Y-X, despite A being flagged UNINTERESTING.
340  *
341  * And when computing --ancestry-path "A..B", the A-X connection is more
342  * important than Y-X, despite both A and Y being flagged UNINTERESTING.
343  */
344 static inline int relevant_commit(struct commit *commit)
345 {
346         return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
347 }
348
349 /*
350  * Return a single relevant commit from a parent list. If we are a TREESAME
351  * commit, and this selects one of our parents, then we can safely simplify to
352  * that parent.
353  */
354 static struct commit *one_relevant_parent(const struct rev_info *revs,
355                                           struct commit_list *orig)
356 {
357         struct commit_list *list = orig;
358         struct commit *relevant = NULL;
359
360         if (!orig)
361                 return NULL;
362
363         /*
364          * For 1-parent commits, or if first-parent-only, then return that
365          * first parent (even if not "relevant" by the above definition).
366          * TREESAME will have been set purely on that parent.
367          */
368         if (revs->first_parent_only || !orig->next)
369                 return orig->item;
370
371         /*
372          * For multi-parent commits, identify a sole relevant parent, if any.
373          * If we have only one relevant parent, then TREESAME will be set purely
374          * with regard to that parent, and we can simplify accordingly.
375          *
376          * If we have more than one relevant parent, or no relevant parents
377          * (and multiple irrelevant ones), then we can't select a parent here
378          * and return NULL.
379          */
380         while (list) {
381                 struct commit *commit = list->item;
382                 list = list->next;
383                 if (relevant_commit(commit)) {
384                         if (relevant)
385                                 return NULL;
386                         relevant = commit;
387                 }
388         }
389         return relevant;
390 }
391
392 /*
393  * The goal is to get REV_TREE_NEW as the result only if the
394  * diff consists of all '+' (and no other changes), REV_TREE_OLD
395  * if the whole diff is removal of old data, and otherwise
396  * REV_TREE_DIFFERENT (of course if the trees are the same we
397  * want REV_TREE_SAME).
398  *
399  * The only time we care about the distinction is when
400  * remove_empty_trees is in effect, in which case we care only about
401  * whether the whole change is REV_TREE_NEW, or if there's another type
402  * of change. Which means we can stop the diff early in either of these
403  * cases:
404  *
405  *   1. We're not using remove_empty_trees at all.
406  *
407  *   2. We saw anything except REV_TREE_NEW.
408  */
409 static int tree_difference = REV_TREE_SAME;
410
411 static void file_add_remove(struct diff_options *options,
412                     int addremove, unsigned mode,
413                     const struct object_id *oid,
414                     int oid_valid,
415                     const char *fullpath, unsigned dirty_submodule)
416 {
417         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
418         struct rev_info *revs = options->change_fn_data;
419
420         tree_difference |= diff;
421         if (!revs->remove_empty_trees || tree_difference != REV_TREE_NEW)
422                 options->flags.has_changes = 1;
423 }
424
425 static void file_change(struct diff_options *options,
426                  unsigned old_mode, unsigned new_mode,
427                  const struct object_id *old_oid,
428                  const struct object_id *new_oid,
429                  int old_oid_valid, int new_oid_valid,
430                  const char *fullpath,
431                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
432 {
433         tree_difference = REV_TREE_DIFFERENT;
434         options->flags.has_changes = 1;
435 }
436
437 static int rev_compare_tree(struct rev_info *revs,
438                             struct commit *parent, struct commit *commit)
439 {
440         struct tree *t1 = parent->tree;
441         struct tree *t2 = commit->tree;
442
443         if (!t1)
444                 return REV_TREE_NEW;
445         if (!t2)
446                 return REV_TREE_OLD;
447
448         if (revs->simplify_by_decoration) {
449                 /*
450                  * If we are simplifying by decoration, then the commit
451                  * is worth showing if it has a tag pointing at it.
452                  */
453                 if (get_name_decoration(&commit->object))
454                         return REV_TREE_DIFFERENT;
455                 /*
456                  * A commit that is not pointed by a tag is uninteresting
457                  * if we are not limited by path.  This means that you will
458                  * see the usual "commits that touch the paths" plus any
459                  * tagged commit by specifying both --simplify-by-decoration
460                  * and pathspec.
461                  */
462                 if (!revs->prune_data.nr)
463                         return REV_TREE_SAME;
464         }
465
466         tree_difference = REV_TREE_SAME;
467         revs->pruning.flags.has_changes = 0;
468         if (diff_tree_oid(&t1->object.oid, &t2->object.oid, "",
469                            &revs->pruning) < 0)
470                 return REV_TREE_DIFFERENT;
471         return tree_difference;
472 }
473
474 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
475 {
476         int retval;
477         struct tree *t1 = commit->tree;
478
479         if (!t1)
480                 return 0;
481
482         tree_difference = REV_TREE_SAME;
483         revs->pruning.flags.has_changes = 0;
484         retval = diff_tree_oid(NULL, &t1->object.oid, "", &revs->pruning);
485
486         return retval >= 0 && (tree_difference == REV_TREE_SAME);
487 }
488
489 struct treesame_state {
490         unsigned int nparents;
491         unsigned char treesame[FLEX_ARRAY];
492 };
493
494 static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
495 {
496         unsigned n = commit_list_count(commit->parents);
497         struct treesame_state *st = xcalloc(1, st_add(sizeof(*st), n));
498         st->nparents = n;
499         add_decoration(&revs->treesame, &commit->object, st);
500         return st;
501 }
502
503 /*
504  * Must be called immediately after removing the nth_parent from a commit's
505  * parent list, if we are maintaining the per-parent treesame[] decoration.
506  * This does not recalculate the master TREESAME flag - update_treesame()
507  * should be called to update it after a sequence of treesame[] modifications
508  * that may have affected it.
509  */
510 static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
511 {
512         struct treesame_state *st;
513         int old_same;
514
515         if (!commit->parents) {
516                 /*
517                  * Have just removed the only parent from a non-merge.
518                  * Different handling, as we lack decoration.
519                  */
520                 if (nth_parent != 0)
521                         die("compact_treesame %u", nth_parent);
522                 old_same = !!(commit->object.flags & TREESAME);
523                 if (rev_same_tree_as_empty(revs, commit))
524                         commit->object.flags |= TREESAME;
525                 else
526                         commit->object.flags &= ~TREESAME;
527                 return old_same;
528         }
529
530         st = lookup_decoration(&revs->treesame, &commit->object);
531         if (!st || nth_parent >= st->nparents)
532                 die("compact_treesame %u", nth_parent);
533
534         old_same = st->treesame[nth_parent];
535         memmove(st->treesame + nth_parent,
536                 st->treesame + nth_parent + 1,
537                 st->nparents - nth_parent - 1);
538
539         /*
540          * If we've just become a non-merge commit, update TREESAME
541          * immediately, and remove the no-longer-needed decoration.
542          * If still a merge, defer update until update_treesame().
543          */
544         if (--st->nparents == 1) {
545                 if (commit->parents->next)
546                         die("compact_treesame parents mismatch");
547                 if (st->treesame[0] && revs->dense)
548                         commit->object.flags |= TREESAME;
549                 else
550                         commit->object.flags &= ~TREESAME;
551                 free(add_decoration(&revs->treesame, &commit->object, NULL));
552         }
553
554         return old_same;
555 }
556
557 static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
558 {
559         if (commit->parents && commit->parents->next) {
560                 unsigned n;
561                 struct treesame_state *st;
562                 struct commit_list *p;
563                 unsigned relevant_parents;
564                 unsigned relevant_change, irrelevant_change;
565
566                 st = lookup_decoration(&revs->treesame, &commit->object);
567                 if (!st)
568                         die("update_treesame %s", oid_to_hex(&commit->object.oid));
569                 relevant_parents = 0;
570                 relevant_change = irrelevant_change = 0;
571                 for (p = commit->parents, n = 0; p; n++, p = p->next) {
572                         if (relevant_commit(p->item)) {
573                                 relevant_change |= !st->treesame[n];
574                                 relevant_parents++;
575                         } else
576                                 irrelevant_change |= !st->treesame[n];
577                 }
578                 if (relevant_parents ? relevant_change : irrelevant_change)
579                         commit->object.flags &= ~TREESAME;
580                 else
581                         commit->object.flags |= TREESAME;
582         }
583
584         return commit->object.flags & TREESAME;
585 }
586
587 static inline int limiting_can_increase_treesame(const struct rev_info *revs)
588 {
589         /*
590          * TREESAME is irrelevant unless prune && dense;
591          * if simplify_history is set, we can't have a mixture of TREESAME and
592          *    !TREESAME INTERESTING parents (and we don't have treesame[]
593          *    decoration anyway);
594          * if first_parent_only is set, then the TREESAME flag is locked
595          *    against the first parent (and again we lack treesame[] decoration).
596          */
597         return revs->prune && revs->dense &&
598                !revs->simplify_history &&
599                !revs->first_parent_only;
600 }
601
602 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
603 {
604         struct commit_list **pp, *parent;
605         struct treesame_state *ts = NULL;
606         int relevant_change = 0, irrelevant_change = 0;
607         int relevant_parents, nth_parent;
608
609         /*
610          * If we don't do pruning, everything is interesting
611          */
612         if (!revs->prune)
613                 return;
614
615         if (!commit->tree)
616                 return;
617
618         if (!commit->parents) {
619                 if (rev_same_tree_as_empty(revs, commit))
620                         commit->object.flags |= TREESAME;
621                 return;
622         }
623
624         /*
625          * Normal non-merge commit? If we don't want to make the
626          * history dense, we consider it always to be a change..
627          */
628         if (!revs->dense && !commit->parents->next)
629                 return;
630
631         for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
632              (parent = *pp) != NULL;
633              pp = &parent->next, nth_parent++) {
634                 struct commit *p = parent->item;
635                 if (relevant_commit(p))
636                         relevant_parents++;
637
638                 if (nth_parent == 1) {
639                         /*
640                          * This our second loop iteration - so we now know
641                          * we're dealing with a merge.
642                          *
643                          * Do not compare with later parents when we care only about
644                          * the first parent chain, in order to avoid derailing the
645                          * traversal to follow a side branch that brought everything
646                          * in the path we are limited to by the pathspec.
647                          */
648                         if (revs->first_parent_only)
649                                 break;
650                         /*
651                          * If this will remain a potentially-simplifiable
652                          * merge, remember per-parent treesame if needed.
653                          * Initialise the array with the comparison from our
654                          * first iteration.
655                          */
656                         if (revs->treesame.name &&
657                             !revs->simplify_history &&
658                             !(commit->object.flags & UNINTERESTING)) {
659                                 ts = initialise_treesame(revs, commit);
660                                 if (!(irrelevant_change || relevant_change))
661                                         ts->treesame[0] = 1;
662                         }
663                 }
664                 if (parse_commit(p) < 0)
665                         die("cannot simplify commit %s (because of %s)",
666                             oid_to_hex(&commit->object.oid),
667                             oid_to_hex(&p->object.oid));
668                 switch (rev_compare_tree(revs, p, commit)) {
669                 case REV_TREE_SAME:
670                         if (!revs->simplify_history || !relevant_commit(p)) {
671                                 /* Even if a merge with an uninteresting
672                                  * side branch brought the entire change
673                                  * we are interested in, we do not want
674                                  * to lose the other branches of this
675                                  * merge, so we just keep going.
676                                  */
677                                 if (ts)
678                                         ts->treesame[nth_parent] = 1;
679                                 continue;
680                         }
681                         parent->next = NULL;
682                         commit->parents = parent;
683                         commit->object.flags |= TREESAME;
684                         return;
685
686                 case REV_TREE_NEW:
687                         if (revs->remove_empty_trees &&
688                             rev_same_tree_as_empty(revs, p)) {
689                                 /* We are adding all the specified
690                                  * paths from this parent, so the
691                                  * history beyond this parent is not
692                                  * interesting.  Remove its parents
693                                  * (they are grandparents for us).
694                                  * IOW, we pretend this parent is a
695                                  * "root" commit.
696                                  */
697                                 if (parse_commit(p) < 0)
698                                         die("cannot simplify commit %s (invalid %s)",
699                                             oid_to_hex(&commit->object.oid),
700                                             oid_to_hex(&p->object.oid));
701                                 p->parents = NULL;
702                         }
703                 /* fallthrough */
704                 case REV_TREE_OLD:
705                 case REV_TREE_DIFFERENT:
706                         if (relevant_commit(p))
707                                 relevant_change = 1;
708                         else
709                                 irrelevant_change = 1;
710                         continue;
711                 }
712                 die("bad tree compare for commit %s", oid_to_hex(&commit->object.oid));
713         }
714
715         /*
716          * TREESAME is straightforward for single-parent commits. For merge
717          * commits, it is most useful to define it so that "irrelevant"
718          * parents cannot make us !TREESAME - if we have any relevant
719          * parents, then we only consider TREESAMEness with respect to them,
720          * allowing irrelevant merges from uninteresting branches to be
721          * simplified away. Only if we have only irrelevant parents do we
722          * base TREESAME on them. Note that this logic is replicated in
723          * update_treesame, which should be kept in sync.
724          */
725         if (relevant_parents ? !relevant_change : !irrelevant_change)
726                 commit->object.flags |= TREESAME;
727 }
728
729 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
730                     struct commit_list *cached_base, struct commit_list **cache)
731 {
732         struct commit_list *new_entry;
733
734         if (cached_base && p->date < cached_base->item->date)
735                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
736         else
737                 new_entry = commit_list_insert_by_date(p, head);
738
739         if (cache && (!*cache || p->date < (*cache)->item->date))
740                 *cache = new_entry;
741 }
742
743 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
744                     struct commit_list **list, struct commit_list **cache_ptr)
745 {
746         struct commit_list *parent = commit->parents;
747         unsigned left_flag;
748         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
749
750         if (commit->object.flags & ADDED)
751                 return 0;
752         commit->object.flags |= ADDED;
753
754         if (revs->include_check &&
755             !revs->include_check(commit, revs->include_check_data))
756                 return 0;
757
758         /*
759          * If the commit is uninteresting, don't try to
760          * prune parents - we want the maximal uninteresting
761          * set.
762          *
763          * Normally we haven't parsed the parent
764          * yet, so we won't have a parent of a parent
765          * here. However, it may turn out that we've
766          * reached this commit some other way (where it
767          * wasn't uninteresting), in which case we need
768          * to mark its parents recursively too..
769          */
770         if (commit->object.flags & UNINTERESTING) {
771                 while (parent) {
772                         struct commit *p = parent->item;
773                         parent = parent->next;
774                         if (p)
775                                 p->object.flags |= UNINTERESTING;
776                         if (parse_commit_gently(p, 1) < 0)
777                                 continue;
778                         if (p->parents)
779                                 mark_parents_uninteresting(p);
780                         if (p->object.flags & SEEN)
781                                 continue;
782                         p->object.flags |= SEEN;
783                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
784                 }
785                 return 0;
786         }
787
788         /*
789          * Ok, the commit wasn't uninteresting. Try to
790          * simplify the commit history and find the parent
791          * that has no differences in the path set if one exists.
792          */
793         try_to_simplify_commit(revs, commit);
794
795         if (revs->no_walk)
796                 return 0;
797
798         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
799
800         for (parent = commit->parents; parent; parent = parent->next) {
801                 struct commit *p = parent->item;
802
803                 if (parse_commit_gently(p, revs->ignore_missing_links) < 0)
804                         return -1;
805                 if (revs->show_source && !p->util)
806                         p->util = commit->util;
807                 p->object.flags |= left_flag;
808                 if (!(p->object.flags & SEEN)) {
809                         p->object.flags |= SEEN;
810                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
811                 }
812                 if (revs->first_parent_only)
813                         break;
814         }
815         return 0;
816 }
817
818 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
819 {
820         struct commit_list *p;
821         int left_count = 0, right_count = 0;
822         int left_first;
823         struct patch_ids ids;
824         unsigned cherry_flag;
825
826         /* First count the commits on the left and on the right */
827         for (p = list; p; p = p->next) {
828                 struct commit *commit = p->item;
829                 unsigned flags = commit->object.flags;
830                 if (flags & BOUNDARY)
831                         ;
832                 else if (flags & SYMMETRIC_LEFT)
833                         left_count++;
834                 else
835                         right_count++;
836         }
837
838         if (!left_count || !right_count)
839                 return;
840
841         left_first = left_count < right_count;
842         init_patch_ids(&ids);
843         ids.diffopts.pathspec = revs->diffopt.pathspec;
844
845         /* Compute patch-ids for one side */
846         for (p = list; p; p = p->next) {
847                 struct commit *commit = p->item;
848                 unsigned flags = commit->object.flags;
849
850                 if (flags & BOUNDARY)
851                         continue;
852                 /*
853                  * If we have fewer left, left_first is set and we omit
854                  * commits on the right branch in this loop.  If we have
855                  * fewer right, we skip the left ones.
856                  */
857                 if (left_first != !!(flags & SYMMETRIC_LEFT))
858                         continue;
859                 add_commit_patch_id(commit, &ids);
860         }
861
862         /* either cherry_mark or cherry_pick are true */
863         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
864
865         /* Check the other side */
866         for (p = list; p; p = p->next) {
867                 struct commit *commit = p->item;
868                 struct patch_id *id;
869                 unsigned flags = commit->object.flags;
870
871                 if (flags & BOUNDARY)
872                         continue;
873                 /*
874                  * If we have fewer left, left_first is set and we omit
875                  * commits on the left branch in this loop.
876                  */
877                 if (left_first == !!(flags & SYMMETRIC_LEFT))
878                         continue;
879
880                 /*
881                  * Have we seen the same patch id?
882                  */
883                 id = has_commit_patch_id(commit, &ids);
884                 if (!id)
885                         continue;
886
887                 commit->object.flags |= cherry_flag;
888                 id->commit->object.flags |= cherry_flag;
889         }
890
891         free_patch_ids(&ids);
892 }
893
894 /* How many extra uninteresting commits we want to see.. */
895 #define SLOP 5
896
897 static int still_interesting(struct commit_list *src, timestamp_t date, int slop,
898                              struct commit **interesting_cache)
899 {
900         /*
901          * No source list at all? We're definitely done..
902          */
903         if (!src)
904                 return 0;
905
906         /*
907          * Does the destination list contain entries with a date
908          * before the source list? Definitely _not_ done.
909          */
910         if (date <= src->item->date)
911                 return SLOP;
912
913         /*
914          * Does the source list still have interesting commits in
915          * it? Definitely not done..
916          */
917         if (!everybody_uninteresting(src, interesting_cache))
918                 return SLOP;
919
920         /* Ok, we're closing in.. */
921         return slop-1;
922 }
923
924 /*
925  * "rev-list --ancestry-path A..B" computes commits that are ancestors
926  * of B but not ancestors of A but further limits the result to those
927  * that are descendants of A.  This takes the list of bottom commits and
928  * the result of "A..B" without --ancestry-path, and limits the latter
929  * further to the ones that can reach one of the commits in "bottom".
930  */
931 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
932 {
933         struct commit_list *p;
934         struct commit_list *rlist = NULL;
935         int made_progress;
936
937         /*
938          * Reverse the list so that it will be likely that we would
939          * process parents before children.
940          */
941         for (p = list; p; p = p->next)
942                 commit_list_insert(p->item, &rlist);
943
944         for (p = bottom; p; p = p->next)
945                 p->item->object.flags |= TMP_MARK;
946
947         /*
948          * Mark the ones that can reach bottom commits in "list",
949          * in a bottom-up fashion.
950          */
951         do {
952                 made_progress = 0;
953                 for (p = rlist; p; p = p->next) {
954                         struct commit *c = p->item;
955                         struct commit_list *parents;
956                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
957                                 continue;
958                         for (parents = c->parents;
959                              parents;
960                              parents = parents->next) {
961                                 if (!(parents->item->object.flags & TMP_MARK))
962                                         continue;
963                                 c->object.flags |= TMP_MARK;
964                                 made_progress = 1;
965                                 break;
966                         }
967                 }
968         } while (made_progress);
969
970         /*
971          * NEEDSWORK: decide if we want to remove parents that are
972          * not marked with TMP_MARK from commit->parents for commits
973          * in the resulting list.  We may not want to do that, though.
974          */
975
976         /*
977          * The ones that are not marked with TMP_MARK are uninteresting
978          */
979         for (p = list; p; p = p->next) {
980                 struct commit *c = p->item;
981                 if (c->object.flags & TMP_MARK)
982                         continue;
983                 c->object.flags |= UNINTERESTING;
984         }
985
986         /* We are done with the TMP_MARK */
987         for (p = list; p; p = p->next)
988                 p->item->object.flags &= ~TMP_MARK;
989         for (p = bottom; p; p = p->next)
990                 p->item->object.flags &= ~TMP_MARK;
991         free_commit_list(rlist);
992 }
993
994 /*
995  * Before walking the history, keep the set of "negative" refs the
996  * caller has asked to exclude.
997  *
998  * This is used to compute "rev-list --ancestry-path A..B", as we need
999  * to filter the result of "A..B" further to the ones that can actually
1000  * reach A.
1001  */
1002 static struct commit_list *collect_bottom_commits(struct commit_list *list)
1003 {
1004         struct commit_list *elem, *bottom = NULL;
1005         for (elem = list; elem; elem = elem->next)
1006                 if (elem->item->object.flags & BOTTOM)
1007                         commit_list_insert(elem->item, &bottom);
1008         return bottom;
1009 }
1010
1011 /* Assumes either left_only or right_only is set */
1012 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
1013 {
1014         struct commit_list *p;
1015
1016         for (p = list; p; p = p->next) {
1017                 struct commit *commit = p->item;
1018
1019                 if (revs->right_only) {
1020                         if (commit->object.flags & SYMMETRIC_LEFT)
1021                                 commit->object.flags |= SHOWN;
1022                 } else  /* revs->left_only is set */
1023                         if (!(commit->object.flags & SYMMETRIC_LEFT))
1024                                 commit->object.flags |= SHOWN;
1025         }
1026 }
1027
1028 static int limit_list(struct rev_info *revs)
1029 {
1030         int slop = SLOP;
1031         timestamp_t date = TIME_MAX;
1032         struct commit_list *list = revs->commits;
1033         struct commit_list *newlist = NULL;
1034         struct commit_list **p = &newlist;
1035         struct commit_list *bottom = NULL;
1036         struct commit *interesting_cache = NULL;
1037
1038         if (revs->ancestry_path) {
1039                 bottom = collect_bottom_commits(list);
1040                 if (!bottom)
1041                         die("--ancestry-path given but there are no bottom commits");
1042         }
1043
1044         while (list) {
1045                 struct commit *commit = pop_commit(&list);
1046                 struct object *obj = &commit->object;
1047                 show_early_output_fn_t show;
1048
1049                 if (commit == interesting_cache)
1050                         interesting_cache = NULL;
1051
1052                 if (revs->max_age != -1 && (commit->date < revs->max_age))
1053                         obj->flags |= UNINTERESTING;
1054                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
1055                         return -1;
1056                 if (obj->flags & UNINTERESTING) {
1057                         mark_parents_uninteresting(commit);
1058                         slop = still_interesting(list, date, slop, &interesting_cache);
1059                         if (slop)
1060                                 continue;
1061                         break;
1062                 }
1063                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1064                         continue;
1065                 date = commit->date;
1066                 p = &commit_list_insert(commit, p)->next;
1067
1068                 show = show_early_output;
1069                 if (!show)
1070                         continue;
1071
1072                 show(revs, newlist);
1073                 show_early_output = NULL;
1074         }
1075         if (revs->cherry_pick || revs->cherry_mark)
1076                 cherry_pick_list(newlist, revs);
1077
1078         if (revs->left_only || revs->right_only)
1079                 limit_left_right(newlist, revs);
1080
1081         if (bottom) {
1082                 limit_to_ancestry(bottom, newlist);
1083                 free_commit_list(bottom);
1084         }
1085
1086         /*
1087          * Check if any commits have become TREESAME by some of their parents
1088          * becoming UNINTERESTING.
1089          */
1090         if (limiting_can_increase_treesame(revs))
1091                 for (list = newlist; list; list = list->next) {
1092                         struct commit *c = list->item;
1093                         if (c->object.flags & (UNINTERESTING | TREESAME))
1094                                 continue;
1095                         update_treesame(revs, c);
1096                 }
1097
1098         revs->commits = newlist;
1099         return 0;
1100 }
1101
1102 /*
1103  * Add an entry to refs->cmdline with the specified information.
1104  * *name is copied.
1105  */
1106 static void add_rev_cmdline(struct rev_info *revs,
1107                             struct object *item,
1108                             const char *name,
1109                             int whence,
1110                             unsigned flags)
1111 {
1112         struct rev_cmdline_info *info = &revs->cmdline;
1113         unsigned int nr = info->nr;
1114
1115         ALLOC_GROW(info->rev, nr + 1, info->alloc);
1116         info->rev[nr].item = item;
1117         info->rev[nr].name = xstrdup(name);
1118         info->rev[nr].whence = whence;
1119         info->rev[nr].flags = flags;
1120         info->nr++;
1121 }
1122
1123 static void add_rev_cmdline_list(struct rev_info *revs,
1124                                  struct commit_list *commit_list,
1125                                  int whence,
1126                                  unsigned flags)
1127 {
1128         while (commit_list) {
1129                 struct object *object = &commit_list->item->object;
1130                 add_rev_cmdline(revs, object, oid_to_hex(&object->oid),
1131                                 whence, flags);
1132                 commit_list = commit_list->next;
1133         }
1134 }
1135
1136 struct all_refs_cb {
1137         int all_flags;
1138         int warned_bad_reflog;
1139         struct rev_info *all_revs;
1140         const char *name_for_errormsg;
1141         struct ref_store *refs;
1142 };
1143
1144 int ref_excluded(struct string_list *ref_excludes, const char *path)
1145 {
1146         struct string_list_item *item;
1147
1148         if (!ref_excludes)
1149                 return 0;
1150         for_each_string_list_item(item, ref_excludes) {
1151                 if (!wildmatch(item->string, path, 0))
1152                         return 1;
1153         }
1154         return 0;
1155 }
1156
1157 static int handle_one_ref(const char *path, const struct object_id *oid,
1158                           int flag, void *cb_data)
1159 {
1160         struct all_refs_cb *cb = cb_data;
1161         struct object *object;
1162
1163         if (ref_excluded(cb->all_revs->ref_excludes, path))
1164             return 0;
1165
1166         object = get_reference(cb->all_revs, path, oid, cb->all_flags);
1167         add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
1168         add_pending_oid(cb->all_revs, path, oid, cb->all_flags);
1169         return 0;
1170 }
1171
1172 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
1173         unsigned flags)
1174 {
1175         cb->all_revs = revs;
1176         cb->all_flags = flags;
1177         revs->rev_input_given = 1;
1178         cb->refs = NULL;
1179 }
1180
1181 void clear_ref_exclusion(struct string_list **ref_excludes_p)
1182 {
1183         if (*ref_excludes_p) {
1184                 string_list_clear(*ref_excludes_p, 0);
1185                 free(*ref_excludes_p);
1186         }
1187         *ref_excludes_p = NULL;
1188 }
1189
1190 void add_ref_exclusion(struct string_list **ref_excludes_p, const char *exclude)
1191 {
1192         if (!*ref_excludes_p) {
1193                 *ref_excludes_p = xcalloc(1, sizeof(**ref_excludes_p));
1194                 (*ref_excludes_p)->strdup_strings = 1;
1195         }
1196         string_list_append(*ref_excludes_p, exclude);
1197 }
1198
1199 static void handle_refs(struct ref_store *refs,
1200                         struct rev_info *revs, unsigned flags,
1201                         int (*for_each)(struct ref_store *, each_ref_fn, void *))
1202 {
1203         struct all_refs_cb cb;
1204
1205         if (!refs) {
1206                 /* this could happen with uninitialized submodules */
1207                 return;
1208         }
1209
1210         init_all_refs_cb(&cb, revs, flags);
1211         for_each(refs, handle_one_ref, &cb);
1212 }
1213
1214 static void handle_one_reflog_commit(struct object_id *oid, void *cb_data)
1215 {
1216         struct all_refs_cb *cb = cb_data;
1217         if (!is_null_oid(oid)) {
1218                 struct object *o = parse_object(oid);
1219                 if (o) {
1220                         o->flags |= cb->all_flags;
1221                         /* ??? CMDLINEFLAGS ??? */
1222                         add_pending_object(cb->all_revs, o, "");
1223                 }
1224                 else if (!cb->warned_bad_reflog) {
1225                         warning("reflog of '%s' references pruned commits",
1226                                 cb->name_for_errormsg);
1227                         cb->warned_bad_reflog = 1;
1228                 }
1229         }
1230 }
1231
1232 static int handle_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
1233                 const char *email, timestamp_t timestamp, int tz,
1234                 const char *message, void *cb_data)
1235 {
1236         handle_one_reflog_commit(ooid, cb_data);
1237         handle_one_reflog_commit(noid, cb_data);
1238         return 0;
1239 }
1240
1241 static int handle_one_reflog(const char *path, const struct object_id *oid,
1242                              int flag, void *cb_data)
1243 {
1244         struct all_refs_cb *cb = cb_data;
1245         cb->warned_bad_reflog = 0;
1246         cb->name_for_errormsg = path;
1247         refs_for_each_reflog_ent(cb->refs, path,
1248                                  handle_one_reflog_ent, cb_data);
1249         return 0;
1250 }
1251
1252 static void add_other_reflogs_to_pending(struct all_refs_cb *cb)
1253 {
1254         struct worktree **worktrees, **p;
1255
1256         worktrees = get_worktrees(0);
1257         for (p = worktrees; *p; p++) {
1258                 struct worktree *wt = *p;
1259
1260                 if (wt->is_current)
1261                         continue;
1262
1263                 cb->refs = get_worktree_ref_store(wt);
1264                 refs_for_each_reflog(cb->refs,
1265                                      handle_one_reflog,
1266                                      cb);
1267         }
1268         free_worktrees(worktrees);
1269 }
1270
1271 void add_reflogs_to_pending(struct rev_info *revs, unsigned flags)
1272 {
1273         struct all_refs_cb cb;
1274
1275         cb.all_revs = revs;
1276         cb.all_flags = flags;
1277         cb.refs = get_main_ref_store();
1278         for_each_reflog(handle_one_reflog, &cb);
1279
1280         if (!revs->single_worktree)
1281                 add_other_reflogs_to_pending(&cb);
1282 }
1283
1284 static void add_cache_tree(struct cache_tree *it, struct rev_info *revs,
1285                            struct strbuf *path)
1286 {
1287         size_t baselen = path->len;
1288         int i;
1289
1290         if (it->entry_count >= 0) {
1291                 struct tree *tree = lookup_tree(&it->oid);
1292                 add_pending_object_with_path(revs, &tree->object, "",
1293                                              040000, path->buf);
1294         }
1295
1296         for (i = 0; i < it->subtree_nr; i++) {
1297                 struct cache_tree_sub *sub = it->down[i];
1298                 strbuf_addf(path, "%s%s", baselen ? "/" : "", sub->name);
1299                 add_cache_tree(sub->cache_tree, revs, path);
1300                 strbuf_setlen(path, baselen);
1301         }
1302
1303 }
1304
1305 static void do_add_index_objects_to_pending(struct rev_info *revs,
1306                                             struct index_state *istate)
1307 {
1308         int i;
1309
1310         for (i = 0; i < istate->cache_nr; i++) {
1311                 struct cache_entry *ce = istate->cache[i];
1312                 struct blob *blob;
1313
1314                 if (S_ISGITLINK(ce->ce_mode))
1315                         continue;
1316
1317                 blob = lookup_blob(&ce->oid);
1318                 if (!blob)
1319                         die("unable to add index blob to traversal");
1320                 add_pending_object_with_path(revs, &blob->object, "",
1321                                              ce->ce_mode, ce->name);
1322         }
1323
1324         if (istate->cache_tree) {
1325                 struct strbuf path = STRBUF_INIT;
1326                 add_cache_tree(istate->cache_tree, revs, &path);
1327                 strbuf_release(&path);
1328         }
1329 }
1330
1331 void add_index_objects_to_pending(struct rev_info *revs, unsigned int flags)
1332 {
1333         struct worktree **worktrees, **p;
1334
1335         read_cache();
1336         do_add_index_objects_to_pending(revs, &the_index);
1337
1338         if (revs->single_worktree)
1339                 return;
1340
1341         worktrees = get_worktrees(0);
1342         for (p = worktrees; *p; p++) {
1343                 struct worktree *wt = *p;
1344                 struct index_state istate = { NULL };
1345
1346                 if (wt->is_current)
1347                         continue; /* current index already taken care of */
1348
1349                 if (read_index_from(&istate,
1350                                     worktree_git_path(wt, "index"),
1351                                     get_worktree_git_dir(wt)) > 0)
1352                         do_add_index_objects_to_pending(revs, &istate);
1353                 discard_index(&istate);
1354         }
1355         free_worktrees(worktrees);
1356 }
1357
1358 static int add_parents_only(struct rev_info *revs, const char *arg_, int flags,
1359                             int exclude_parent)
1360 {
1361         struct object_id oid;
1362         struct object *it;
1363         struct commit *commit;
1364         struct commit_list *parents;
1365         int parent_number;
1366         const char *arg = arg_;
1367
1368         if (*arg == '^') {
1369                 flags ^= UNINTERESTING | BOTTOM;
1370                 arg++;
1371         }
1372         if (get_oid_committish(arg, &oid))
1373                 return 0;
1374         while (1) {
1375                 it = get_reference(revs, arg, &oid, 0);
1376                 if (!it && revs->ignore_missing)
1377                         return 0;
1378                 if (it->type != OBJ_TAG)
1379                         break;
1380                 if (!((struct tag*)it)->tagged)
1381                         return 0;
1382                 oidcpy(&oid, &((struct tag*)it)->tagged->oid);
1383         }
1384         if (it->type != OBJ_COMMIT)
1385                 return 0;
1386         commit = (struct commit *)it;
1387         if (exclude_parent &&
1388             exclude_parent > commit_list_count(commit->parents))
1389                 return 0;
1390         for (parents = commit->parents, parent_number = 1;
1391              parents;
1392              parents = parents->next, parent_number++) {
1393                 if (exclude_parent && parent_number != exclude_parent)
1394                         continue;
1395
1396                 it = &parents->item->object;
1397                 it->flags |= flags;
1398                 add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
1399                 add_pending_object(revs, it, arg);
1400         }
1401         return 1;
1402 }
1403
1404 void init_revisions(struct rev_info *revs, const char *prefix)
1405 {
1406         memset(revs, 0, sizeof(*revs));
1407
1408         revs->abbrev = DEFAULT_ABBREV;
1409         revs->ignore_merges = 1;
1410         revs->simplify_history = 1;
1411         revs->pruning.flags.recursive = 1;
1412         revs->pruning.flags.quick = 1;
1413         revs->pruning.add_remove = file_add_remove;
1414         revs->pruning.change = file_change;
1415         revs->pruning.change_fn_data = revs;
1416         revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1417         revs->dense = 1;
1418         revs->prefix = prefix;
1419         revs->max_age = -1;
1420         revs->min_age = -1;
1421         revs->skip_count = -1;
1422         revs->max_count = -1;
1423         revs->max_parents = -1;
1424         revs->expand_tabs_in_log = -1;
1425
1426         revs->commit_format = CMIT_FMT_DEFAULT;
1427         revs->expand_tabs_in_log_default = 8;
1428
1429         init_grep_defaults();
1430         grep_init(&revs->grep_filter, prefix);
1431         revs->grep_filter.status_only = 1;
1432
1433         diff_setup(&revs->diffopt);
1434         if (prefix && !revs->diffopt.prefix) {
1435                 revs->diffopt.prefix = prefix;
1436                 revs->diffopt.prefix_length = strlen(prefix);
1437         }
1438
1439         revs->notes_opt.use_default_notes = -1;
1440 }
1441
1442 static void add_pending_commit_list(struct rev_info *revs,
1443                                     struct commit_list *commit_list,
1444                                     unsigned int flags)
1445 {
1446         while (commit_list) {
1447                 struct object *object = &commit_list->item->object;
1448                 object->flags |= flags;
1449                 add_pending_object(revs, object, oid_to_hex(&object->oid));
1450                 commit_list = commit_list->next;
1451         }
1452 }
1453
1454 static void prepare_show_merge(struct rev_info *revs)
1455 {
1456         struct commit_list *bases;
1457         struct commit *head, *other;
1458         struct object_id oid;
1459         const char **prune = NULL;
1460         int i, prune_num = 1; /* counting terminating NULL */
1461
1462         if (get_oid("HEAD", &oid))
1463                 die("--merge without HEAD?");
1464         head = lookup_commit_or_die(&oid, "HEAD");
1465         if (get_oid("MERGE_HEAD", &oid))
1466                 die("--merge without MERGE_HEAD?");
1467         other = lookup_commit_or_die(&oid, "MERGE_HEAD");
1468         add_pending_object(revs, &head->object, "HEAD");
1469         add_pending_object(revs, &other->object, "MERGE_HEAD");
1470         bases = get_merge_bases(head, other);
1471         add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
1472         add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
1473         free_commit_list(bases);
1474         head->object.flags |= SYMMETRIC_LEFT;
1475
1476         if (!active_nr)
1477                 read_cache();
1478         for (i = 0; i < active_nr; i++) {
1479                 const struct cache_entry *ce = active_cache[i];
1480                 if (!ce_stage(ce))
1481                         continue;
1482                 if (ce_path_match(ce, &revs->prune_data, NULL)) {
1483                         prune_num++;
1484                         REALLOC_ARRAY(prune, prune_num);
1485                         prune[prune_num-2] = ce->name;
1486                         prune[prune_num-1] = NULL;
1487                 }
1488                 while ((i+1 < active_nr) &&
1489                        ce_same_name(ce, active_cache[i+1]))
1490                         i++;
1491         }
1492         clear_pathspec(&revs->prune_data);
1493         parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
1494                        PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
1495         revs->limited = 1;
1496 }
1497
1498 static int dotdot_missing(const char *arg, char *dotdot,
1499                           struct rev_info *revs, int symmetric)
1500 {
1501         if (revs->ignore_missing)
1502                 return 0;
1503         /* de-munge so we report the full argument */
1504         *dotdot = '.';
1505         die(symmetric
1506             ? "Invalid symmetric difference expression %s"
1507             : "Invalid revision range %s", arg);
1508 }
1509
1510 static int handle_dotdot_1(const char *arg, char *dotdot,
1511                            struct rev_info *revs, int flags,
1512                            int cant_be_filename,
1513                            struct object_context *a_oc,
1514                            struct object_context *b_oc)
1515 {
1516         const char *a_name, *b_name;
1517         struct object_id a_oid, b_oid;
1518         struct object *a_obj, *b_obj;
1519         unsigned int a_flags, b_flags;
1520         int symmetric = 0;
1521         unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
1522         unsigned int oc_flags = GET_OID_COMMITTISH | GET_OID_RECORD_PATH;
1523
1524         a_name = arg;
1525         if (!*a_name)
1526                 a_name = "HEAD";
1527
1528         b_name = dotdot + 2;
1529         if (*b_name == '.') {
1530                 symmetric = 1;
1531                 b_name++;
1532         }
1533         if (!*b_name)
1534                 b_name = "HEAD";
1535
1536         if (get_oid_with_context(a_name, oc_flags, &a_oid, a_oc) ||
1537             get_oid_with_context(b_name, oc_flags, &b_oid, b_oc))
1538                 return -1;
1539
1540         if (!cant_be_filename) {
1541                 *dotdot = '.';
1542                 verify_non_filename(revs->prefix, arg);
1543                 *dotdot = '\0';
1544         }
1545
1546         a_obj = parse_object(&a_oid);
1547         b_obj = parse_object(&b_oid);
1548         if (!a_obj || !b_obj)
1549                 return dotdot_missing(arg, dotdot, revs, symmetric);
1550
1551         if (!symmetric) {
1552                 /* just A..B */
1553                 b_flags = flags;
1554                 a_flags = flags_exclude;
1555         } else {
1556                 /* A...B -- find merge bases between the two */
1557                 struct commit *a, *b;
1558                 struct commit_list *exclude;
1559
1560                 a = lookup_commit_reference(&a_obj->oid);
1561                 b = lookup_commit_reference(&b_obj->oid);
1562                 if (!a || !b)
1563                         return dotdot_missing(arg, dotdot, revs, symmetric);
1564
1565                 exclude = get_merge_bases(a, b);
1566                 add_rev_cmdline_list(revs, exclude, REV_CMD_MERGE_BASE,
1567                                      flags_exclude);
1568                 add_pending_commit_list(revs, exclude, flags_exclude);
1569                 free_commit_list(exclude);
1570
1571                 b_flags = flags;
1572                 a_flags = flags | SYMMETRIC_LEFT;
1573         }
1574
1575         a_obj->flags |= a_flags;
1576         b_obj->flags |= b_flags;
1577         add_rev_cmdline(revs, a_obj, a_name, REV_CMD_LEFT, a_flags);
1578         add_rev_cmdline(revs, b_obj, b_name, REV_CMD_RIGHT, b_flags);
1579         add_pending_object_with_path(revs, a_obj, a_name, a_oc->mode, a_oc->path);
1580         add_pending_object_with_path(revs, b_obj, b_name, b_oc->mode, b_oc->path);
1581         return 0;
1582 }
1583
1584 static int handle_dotdot(const char *arg,
1585                          struct rev_info *revs, int flags,
1586                          int cant_be_filename)
1587 {
1588         struct object_context a_oc, b_oc;
1589         char *dotdot = strstr(arg, "..");
1590         int ret;
1591
1592         if (!dotdot)
1593                 return -1;
1594
1595         memset(&a_oc, 0, sizeof(a_oc));
1596         memset(&b_oc, 0, sizeof(b_oc));
1597
1598         *dotdot = '\0';
1599         ret = handle_dotdot_1(arg, dotdot, revs, flags, cant_be_filename,
1600                               &a_oc, &b_oc);
1601         *dotdot = '.';
1602
1603         free(a_oc.path);
1604         free(b_oc.path);
1605
1606         return ret;
1607 }
1608
1609 int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
1610 {
1611         struct object_context oc;
1612         char *mark;
1613         struct object *object;
1614         struct object_id oid;
1615         int local_flags;
1616         const char *arg = arg_;
1617         int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
1618         unsigned get_sha1_flags = GET_OID_RECORD_PATH;
1619
1620         flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
1621
1622         if (!cant_be_filename && !strcmp(arg, "..")) {
1623                 /*
1624                  * Just ".."?  That is not a range but the
1625                  * pathspec for the parent directory.
1626                  */
1627                 return -1;
1628         }
1629
1630         if (!handle_dotdot(arg, revs, flags, revarg_opt))
1631                 return 0;
1632
1633         mark = strstr(arg, "^@");
1634         if (mark && !mark[2]) {
1635                 *mark = 0;
1636                 if (add_parents_only(revs, arg, flags, 0))
1637                         return 0;
1638                 *mark = '^';
1639         }
1640         mark = strstr(arg, "^!");
1641         if (mark && !mark[2]) {
1642                 *mark = 0;
1643                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), 0))
1644                         *mark = '^';
1645         }
1646         mark = strstr(arg, "^-");
1647         if (mark) {
1648                 int exclude_parent = 1;
1649
1650                 if (mark[2]) {
1651                         char *end;
1652                         exclude_parent = strtoul(mark + 2, &end, 10);
1653                         if (*end != '\0' || !exclude_parent)
1654                                 return -1;
1655                 }
1656
1657                 *mark = 0;
1658                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), exclude_parent))
1659                         *mark = '^';
1660         }
1661
1662         local_flags = 0;
1663         if (*arg == '^') {
1664                 local_flags = UNINTERESTING | BOTTOM;
1665                 arg++;
1666         }
1667
1668         if (revarg_opt & REVARG_COMMITTISH)
1669                 get_sha1_flags |= GET_OID_COMMITTISH;
1670
1671         if (get_oid_with_context(arg, get_sha1_flags, &oid, &oc))
1672                 return revs->ignore_missing ? 0 : -1;
1673         if (!cant_be_filename)
1674                 verify_non_filename(revs->prefix, arg);
1675         object = get_reference(revs, arg, &oid, flags ^ local_flags);
1676         add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
1677         add_pending_object_with_path(revs, object, arg, oc.mode, oc.path);
1678         free(oc.path);
1679         return 0;
1680 }
1681
1682 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
1683                                      struct argv_array *prune)
1684 {
1685         while (strbuf_getline(sb, stdin) != EOF)
1686                 argv_array_push(prune, sb->buf);
1687 }
1688
1689 static void read_revisions_from_stdin(struct rev_info *revs,
1690                                       struct argv_array *prune)
1691 {
1692         struct strbuf sb;
1693         int seen_dashdash = 0;
1694         int save_warning;
1695
1696         save_warning = warn_on_object_refname_ambiguity;
1697         warn_on_object_refname_ambiguity = 0;
1698
1699         strbuf_init(&sb, 1000);
1700         while (strbuf_getline(&sb, stdin) != EOF) {
1701                 int len = sb.len;
1702                 if (!len)
1703                         break;
1704                 if (sb.buf[0] == '-') {
1705                         if (len == 2 && sb.buf[1] == '-') {
1706                                 seen_dashdash = 1;
1707                                 break;
1708                         }
1709                         die("options not supported in --stdin mode");
1710                 }
1711                 if (handle_revision_arg(sb.buf, revs, 0,
1712                                         REVARG_CANNOT_BE_FILENAME))
1713                         die("bad revision '%s'", sb.buf);
1714         }
1715         if (seen_dashdash)
1716                 read_pathspec_from_stdin(revs, &sb, prune);
1717
1718         strbuf_release(&sb);
1719         warn_on_object_refname_ambiguity = save_warning;
1720 }
1721
1722 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1723 {
1724         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1725 }
1726
1727 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1728 {
1729         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1730 }
1731
1732 static void add_message_grep(struct rev_info *revs, const char *pattern)
1733 {
1734         add_grep(revs, pattern, GREP_PATTERN_BODY);
1735 }
1736
1737 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1738                                int *unkc, const char **unkv)
1739 {
1740         const char *arg = argv[0];
1741         const char *optarg;
1742         int argcount;
1743
1744         /* pseudo revision arguments */
1745         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1746             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1747             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1748             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1749             !strcmp(arg, "--bisect") || starts_with(arg, "--glob=") ||
1750             !strcmp(arg, "--indexed-objects") ||
1751             starts_with(arg, "--exclude=") ||
1752             starts_with(arg, "--branches=") || starts_with(arg, "--tags=") ||
1753             starts_with(arg, "--remotes=") || starts_with(arg, "--no-walk="))
1754         {
1755                 unkv[(*unkc)++] = arg;
1756                 return 1;
1757         }
1758
1759         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1760                 revs->max_count = atoi(optarg);
1761                 revs->no_walk = 0;
1762                 return argcount;
1763         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1764                 revs->skip_count = atoi(optarg);
1765                 return argcount;
1766         } else if ((*arg == '-') && isdigit(arg[1])) {
1767                 /* accept -<digit>, like traditional "head" */
1768                 if (strtol_i(arg + 1, 10, &revs->max_count) < 0 ||
1769                     revs->max_count < 0)
1770                         die("'%s': not a non-negative integer", arg + 1);
1771                 revs->no_walk = 0;
1772         } else if (!strcmp(arg, "-n")) {
1773                 if (argc <= 1)
1774                         return error("-n requires an argument");
1775                 revs->max_count = atoi(argv[1]);
1776                 revs->no_walk = 0;
1777                 return 2;
1778         } else if (skip_prefix(arg, "-n", &optarg)) {
1779                 revs->max_count = atoi(optarg);
1780                 revs->no_walk = 0;
1781         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1782                 revs->max_age = atoi(optarg);
1783                 return argcount;
1784         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1785                 revs->max_age = approxidate(optarg);
1786                 return argcount;
1787         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1788                 revs->max_age = approxidate(optarg);
1789                 return argcount;
1790         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1791                 revs->min_age = atoi(optarg);
1792                 return argcount;
1793         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1794                 revs->min_age = approxidate(optarg);
1795                 return argcount;
1796         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1797                 revs->min_age = approxidate(optarg);
1798                 return argcount;
1799         } else if (!strcmp(arg, "--first-parent")) {
1800                 revs->first_parent_only = 1;
1801         } else if (!strcmp(arg, "--ancestry-path")) {
1802                 revs->ancestry_path = 1;
1803                 revs->simplify_history = 0;
1804                 revs->limited = 1;
1805         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1806                 init_reflog_walk(&revs->reflog_info);
1807         } else if (!strcmp(arg, "--default")) {
1808                 if (argc <= 1)
1809                         return error("bad --default argument");
1810                 revs->def = argv[1];
1811                 return 2;
1812         } else if (!strcmp(arg, "--merge")) {
1813                 revs->show_merge = 1;
1814         } else if (!strcmp(arg, "--topo-order")) {
1815                 revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1816                 revs->topo_order = 1;
1817         } else if (!strcmp(arg, "--simplify-merges")) {
1818                 revs->simplify_merges = 1;
1819                 revs->topo_order = 1;
1820                 revs->rewrite_parents = 1;
1821                 revs->simplify_history = 0;
1822                 revs->limited = 1;
1823         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1824                 revs->simplify_merges = 1;
1825                 revs->topo_order = 1;
1826                 revs->rewrite_parents = 1;
1827                 revs->simplify_history = 0;
1828                 revs->simplify_by_decoration = 1;
1829                 revs->limited = 1;
1830                 revs->prune = 1;
1831                 load_ref_decorations(NULL, DECORATE_SHORT_REFS);
1832         } else if (!strcmp(arg, "--date-order")) {
1833                 revs->sort_order = REV_SORT_BY_COMMIT_DATE;
1834                 revs->topo_order = 1;
1835         } else if (!strcmp(arg, "--author-date-order")) {
1836                 revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
1837                 revs->topo_order = 1;
1838         } else if (!strcmp(arg, "--early-output")) {
1839                 revs->early_output = 100;
1840                 revs->topo_order = 1;
1841         } else if (skip_prefix(arg, "--early-output=", &optarg)) {
1842                 if (strtoul_ui(optarg, 10, &revs->early_output) < 0)
1843                         die("'%s': not a non-negative integer", optarg);
1844                 revs->topo_order = 1;
1845         } else if (!strcmp(arg, "--parents")) {
1846                 revs->rewrite_parents = 1;
1847                 revs->print_parents = 1;
1848         } else if (!strcmp(arg, "--dense")) {
1849                 revs->dense = 1;
1850         } else if (!strcmp(arg, "--sparse")) {
1851                 revs->dense = 0;
1852         } else if (!strcmp(arg, "--in-commit-order")) {
1853                 revs->tree_blobs_in_commit_order = 1;
1854         } else if (!strcmp(arg, "--remove-empty")) {
1855                 revs->remove_empty_trees = 1;
1856         } else if (!strcmp(arg, "--merges")) {
1857                 revs->min_parents = 2;
1858         } else if (!strcmp(arg, "--no-merges")) {
1859                 revs->max_parents = 1;
1860         } else if (skip_prefix(arg, "--min-parents=", &optarg)) {
1861                 revs->min_parents = atoi(optarg);
1862         } else if (!strcmp(arg, "--no-min-parents")) {
1863                 revs->min_parents = 0;
1864         } else if (skip_prefix(arg, "--max-parents=", &optarg)) {
1865                 revs->max_parents = atoi(optarg);
1866         } else if (!strcmp(arg, "--no-max-parents")) {
1867                 revs->max_parents = -1;
1868         } else if (!strcmp(arg, "--boundary")) {
1869                 revs->boundary = 1;
1870         } else if (!strcmp(arg, "--left-right")) {
1871                 revs->left_right = 1;
1872         } else if (!strcmp(arg, "--left-only")) {
1873                 if (revs->right_only)
1874                         die("--left-only is incompatible with --right-only"
1875                             " or --cherry");
1876                 revs->left_only = 1;
1877         } else if (!strcmp(arg, "--right-only")) {
1878                 if (revs->left_only)
1879                         die("--right-only is incompatible with --left-only");
1880                 revs->right_only = 1;
1881         } else if (!strcmp(arg, "--cherry")) {
1882                 if (revs->left_only)
1883                         die("--cherry is incompatible with --left-only");
1884                 revs->cherry_mark = 1;
1885                 revs->right_only = 1;
1886                 revs->max_parents = 1;
1887                 revs->limited = 1;
1888         } else if (!strcmp(arg, "--count")) {
1889                 revs->count = 1;
1890         } else if (!strcmp(arg, "--cherry-mark")) {
1891                 if (revs->cherry_pick)
1892                         die("--cherry-mark is incompatible with --cherry-pick");
1893                 revs->cherry_mark = 1;
1894                 revs->limited = 1; /* needs limit_list() */
1895         } else if (!strcmp(arg, "--cherry-pick")) {
1896                 if (revs->cherry_mark)
1897                         die("--cherry-pick is incompatible with --cherry-mark");
1898                 revs->cherry_pick = 1;
1899                 revs->limited = 1;
1900         } else if (!strcmp(arg, "--objects")) {
1901                 revs->tag_objects = 1;
1902                 revs->tree_objects = 1;
1903                 revs->blob_objects = 1;
1904         } else if (!strcmp(arg, "--objects-edge")) {
1905                 revs->tag_objects = 1;
1906                 revs->tree_objects = 1;
1907                 revs->blob_objects = 1;
1908                 revs->edge_hint = 1;
1909         } else if (!strcmp(arg, "--objects-edge-aggressive")) {
1910                 revs->tag_objects = 1;
1911                 revs->tree_objects = 1;
1912                 revs->blob_objects = 1;
1913                 revs->edge_hint = 1;
1914                 revs->edge_hint_aggressive = 1;
1915         } else if (!strcmp(arg, "--verify-objects")) {
1916                 revs->tag_objects = 1;
1917                 revs->tree_objects = 1;
1918                 revs->blob_objects = 1;
1919                 revs->verify_objects = 1;
1920         } else if (!strcmp(arg, "--unpacked")) {
1921                 revs->unpacked = 1;
1922         } else if (starts_with(arg, "--unpacked=")) {
1923                 die("--unpacked=<packfile> no longer supported.");
1924         } else if (!strcmp(arg, "-r")) {
1925                 revs->diff = 1;
1926                 revs->diffopt.flags.recursive = 1;
1927         } else if (!strcmp(arg, "-t")) {
1928                 revs->diff = 1;
1929                 revs->diffopt.flags.recursive = 1;
1930                 revs->diffopt.flags.tree_in_recursive = 1;
1931         } else if (!strcmp(arg, "-m")) {
1932                 revs->ignore_merges = 0;
1933         } else if (!strcmp(arg, "-c")) {
1934                 revs->diff = 1;
1935                 revs->dense_combined_merges = 0;
1936                 revs->combine_merges = 1;
1937         } else if (!strcmp(arg, "--cc")) {
1938                 revs->diff = 1;
1939                 revs->dense_combined_merges = 1;
1940                 revs->combine_merges = 1;
1941         } else if (!strcmp(arg, "-v")) {
1942                 revs->verbose_header = 1;
1943         } else if (!strcmp(arg, "--pretty")) {
1944                 revs->verbose_header = 1;
1945                 revs->pretty_given = 1;
1946                 get_commit_format(NULL, revs);
1947         } else if (skip_prefix(arg, "--pretty=", &optarg) ||
1948                    skip_prefix(arg, "--format=", &optarg)) {
1949                 /*
1950                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1951                  * not allowed, since the argument is optional.
1952                  */
1953                 revs->verbose_header = 1;
1954                 revs->pretty_given = 1;
1955                 get_commit_format(optarg, revs);
1956         } else if (!strcmp(arg, "--expand-tabs")) {
1957                 revs->expand_tabs_in_log = 8;
1958         } else if (!strcmp(arg, "--no-expand-tabs")) {
1959                 revs->expand_tabs_in_log = 0;
1960         } else if (skip_prefix(arg, "--expand-tabs=", &arg)) {
1961                 int val;
1962                 if (strtol_i(arg, 10, &val) < 0 || val < 0)
1963                         die("'%s': not a non-negative integer", arg);
1964                 revs->expand_tabs_in_log = val;
1965         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
1966                 revs->show_notes = 1;
1967                 revs->show_notes_given = 1;
1968                 revs->notes_opt.use_default_notes = 1;
1969         } else if (!strcmp(arg, "--show-signature")) {
1970                 revs->show_signature = 1;
1971         } else if (!strcmp(arg, "--no-show-signature")) {
1972                 revs->show_signature = 0;
1973         } else if (!strcmp(arg, "--show-linear-break")) {
1974                 revs->break_bar = "                    ..........";
1975                 revs->track_linear = 1;
1976                 revs->track_first_time = 1;
1977         } else if (skip_prefix(arg, "--show-linear-break=", &optarg)) {
1978                 revs->break_bar = xstrdup(optarg);
1979                 revs->track_linear = 1;
1980                 revs->track_first_time = 1;
1981         } else if (skip_prefix(arg, "--show-notes=", &optarg) ||
1982                    skip_prefix(arg, "--notes=", &optarg)) {
1983                 struct strbuf buf = STRBUF_INIT;
1984                 revs->show_notes = 1;
1985                 revs->show_notes_given = 1;
1986                 if (starts_with(arg, "--show-notes=") &&
1987                     revs->notes_opt.use_default_notes < 0)
1988                         revs->notes_opt.use_default_notes = 1;
1989                 strbuf_addstr(&buf, optarg);
1990                 expand_notes_ref(&buf);
1991                 string_list_append(&revs->notes_opt.extra_notes_refs,
1992                                    strbuf_detach(&buf, NULL));
1993         } else if (!strcmp(arg, "--no-notes")) {
1994                 revs->show_notes = 0;
1995                 revs->show_notes_given = 1;
1996                 revs->notes_opt.use_default_notes = -1;
1997                 /* we have been strdup'ing ourselves, so trick
1998                  * string_list into free()ing strings */
1999                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
2000                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
2001                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
2002         } else if (!strcmp(arg, "--standard-notes")) {
2003                 revs->show_notes_given = 1;
2004                 revs->notes_opt.use_default_notes = 1;
2005         } else if (!strcmp(arg, "--no-standard-notes")) {
2006                 revs->notes_opt.use_default_notes = 0;
2007         } else if (!strcmp(arg, "--oneline")) {
2008                 revs->verbose_header = 1;
2009                 get_commit_format("oneline", revs);
2010                 revs->pretty_given = 1;
2011                 revs->abbrev_commit = 1;
2012         } else if (!strcmp(arg, "--graph")) {
2013                 revs->topo_order = 1;
2014                 revs->rewrite_parents = 1;
2015                 revs->graph = graph_init(revs);
2016         } else if (!strcmp(arg, "--root")) {
2017                 revs->show_root_diff = 1;
2018         } else if (!strcmp(arg, "--no-commit-id")) {
2019                 revs->no_commit_id = 1;
2020         } else if (!strcmp(arg, "--always")) {
2021                 revs->always_show_header = 1;
2022         } else if (!strcmp(arg, "--no-abbrev")) {
2023                 revs->abbrev = 0;
2024         } else if (!strcmp(arg, "--abbrev")) {
2025                 revs->abbrev = DEFAULT_ABBREV;
2026         } else if (skip_prefix(arg, "--abbrev=", &optarg)) {
2027                 revs->abbrev = strtoul(optarg, NULL, 10);
2028                 if (revs->abbrev < MINIMUM_ABBREV)
2029                         revs->abbrev = MINIMUM_ABBREV;
2030                 else if (revs->abbrev > 40)
2031                         revs->abbrev = 40;
2032         } else if (!strcmp(arg, "--abbrev-commit")) {
2033                 revs->abbrev_commit = 1;
2034                 revs->abbrev_commit_given = 1;
2035         } else if (!strcmp(arg, "--no-abbrev-commit")) {
2036                 revs->abbrev_commit = 0;
2037         } else if (!strcmp(arg, "--full-diff")) {
2038                 revs->diff = 1;
2039                 revs->full_diff = 1;
2040         } else if (!strcmp(arg, "--full-history")) {
2041                 revs->simplify_history = 0;
2042         } else if (!strcmp(arg, "--relative-date")) {
2043                 revs->date_mode.type = DATE_RELATIVE;
2044                 revs->date_mode_explicit = 1;
2045         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
2046                 parse_date_format(optarg, &revs->date_mode);
2047                 revs->date_mode_explicit = 1;
2048                 return argcount;
2049         } else if (!strcmp(arg, "--log-size")) {
2050                 revs->show_log_size = 1;
2051         }
2052         /*
2053          * Grepping the commit log
2054          */
2055         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
2056                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
2057                 return argcount;
2058         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
2059                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
2060                 return argcount;
2061         } else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
2062                 add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
2063                 return argcount;
2064         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
2065                 add_message_grep(revs, optarg);
2066                 return argcount;
2067         } else if (!strcmp(arg, "--grep-debug")) {
2068                 revs->grep_filter.debug = 1;
2069         } else if (!strcmp(arg, "--basic-regexp")) {
2070                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_BRE;
2071         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
2072                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_ERE;
2073         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
2074                 revs->grep_filter.ignore_case = 1;
2075                 revs->diffopt.flags.pickaxe_ignore_case = 1;
2076         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
2077                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_FIXED;
2078         } else if (!strcmp(arg, "--perl-regexp") || !strcmp(arg, "-P")) {
2079                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_PCRE;
2080         } else if (!strcmp(arg, "--all-match")) {
2081                 revs->grep_filter.all_match = 1;
2082         } else if (!strcmp(arg, "--invert-grep")) {
2083                 revs->invert_grep = 1;
2084         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
2085                 if (strcmp(optarg, "none"))
2086                         git_log_output_encoding = xstrdup(optarg);
2087                 else
2088                         git_log_output_encoding = "";
2089                 return argcount;
2090         } else if (!strcmp(arg, "--reverse")) {
2091                 revs->reverse ^= 1;
2092         } else if (!strcmp(arg, "--children")) {
2093                 revs->children.name = "children";
2094                 revs->limited = 1;
2095         } else if (!strcmp(arg, "--ignore-missing")) {
2096                 revs->ignore_missing = 1;
2097         } else {
2098                 int opts = diff_opt_parse(&revs->diffopt, argv, argc, revs->prefix);
2099                 if (!opts)
2100                         unkv[(*unkc)++] = arg;
2101                 return opts;
2102         }
2103         if (revs->graph && revs->track_linear)
2104                 die("--show-linear-break and --graph are incompatible");
2105
2106         return 1;
2107 }
2108
2109 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
2110                         const struct option *options,
2111                         const char * const usagestr[])
2112 {
2113         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
2114                                     &ctx->cpidx, ctx->out);
2115         if (n <= 0) {
2116                 error("unknown option `%s'", ctx->argv[0]);
2117                 usage_with_options(usagestr, options);
2118         }
2119         ctx->argv += n;
2120         ctx->argc -= n;
2121 }
2122
2123 static int for_each_bisect_ref(struct ref_store *refs, each_ref_fn fn,
2124                                void *cb_data, const char *term)
2125 {
2126         struct strbuf bisect_refs = STRBUF_INIT;
2127         int status;
2128         strbuf_addf(&bisect_refs, "refs/bisect/%s", term);
2129         status = refs_for_each_fullref_in(refs, bisect_refs.buf, fn, cb_data, 0);
2130         strbuf_release(&bisect_refs);
2131         return status;
2132 }
2133
2134 static int for_each_bad_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2135 {
2136         return for_each_bisect_ref(refs, fn, cb_data, term_bad);
2137 }
2138
2139 static int for_each_good_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2140 {
2141         return for_each_bisect_ref(refs, fn, cb_data, term_good);
2142 }
2143
2144 static int handle_revision_pseudo_opt(const char *submodule,
2145                                 struct rev_info *revs,
2146                                 int argc, const char **argv, int *flags)
2147 {
2148         const char *arg = argv[0];
2149         const char *optarg;
2150         struct ref_store *refs;
2151         int argcount;
2152
2153         if (submodule) {
2154                 /*
2155                  * We need some something like get_submodule_worktrees()
2156                  * before we can go through all worktrees of a submodule,
2157                  * .e.g with adding all HEADs from --all, which is not
2158                  * supported right now, so stick to single worktree.
2159                  */
2160                 if (!revs->single_worktree)
2161                         die("BUG: --single-worktree cannot be used together with submodule");
2162                 refs = get_submodule_ref_store(submodule);
2163         } else
2164                 refs = get_main_ref_store();
2165
2166         /*
2167          * NOTE!
2168          *
2169          * Commands like "git shortlog" will not accept the options below
2170          * unless parse_revision_opt queues them (as opposed to erroring
2171          * out).
2172          *
2173          * When implementing your new pseudo-option, remember to
2174          * register it in the list at the top of handle_revision_opt.
2175          */
2176         if (!strcmp(arg, "--all")) {
2177                 handle_refs(refs, revs, *flags, refs_for_each_ref);
2178                 handle_refs(refs, revs, *flags, refs_head_ref);
2179                 if (!revs->single_worktree) {
2180                         struct all_refs_cb cb;
2181
2182                         init_all_refs_cb(&cb, revs, *flags);
2183                         other_head_refs(handle_one_ref, &cb);
2184                 }
2185                 clear_ref_exclusion(&revs->ref_excludes);
2186         } else if (!strcmp(arg, "--branches")) {
2187                 handle_refs(refs, revs, *flags, refs_for_each_branch_ref);
2188                 clear_ref_exclusion(&revs->ref_excludes);
2189         } else if (!strcmp(arg, "--bisect")) {
2190                 read_bisect_terms(&term_bad, &term_good);
2191                 handle_refs(refs, revs, *flags, for_each_bad_bisect_ref);
2192                 handle_refs(refs, revs, *flags ^ (UNINTERESTING | BOTTOM),
2193                             for_each_good_bisect_ref);
2194                 revs->bisect = 1;
2195         } else if (!strcmp(arg, "--tags")) {
2196                 handle_refs(refs, revs, *flags, refs_for_each_tag_ref);
2197                 clear_ref_exclusion(&revs->ref_excludes);
2198         } else if (!strcmp(arg, "--remotes")) {
2199                 handle_refs(refs, revs, *flags, refs_for_each_remote_ref);
2200                 clear_ref_exclusion(&revs->ref_excludes);
2201         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
2202                 struct all_refs_cb cb;
2203                 init_all_refs_cb(&cb, revs, *flags);
2204                 for_each_glob_ref(handle_one_ref, optarg, &cb);
2205                 clear_ref_exclusion(&revs->ref_excludes);
2206                 return argcount;
2207         } else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
2208                 add_ref_exclusion(&revs->ref_excludes, optarg);
2209                 return argcount;
2210         } else if (skip_prefix(arg, "--branches=", &optarg)) {
2211                 struct all_refs_cb cb;
2212                 init_all_refs_cb(&cb, revs, *flags);
2213                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/heads/", &cb);
2214                 clear_ref_exclusion(&revs->ref_excludes);
2215         } else if (skip_prefix(arg, "--tags=", &optarg)) {
2216                 struct all_refs_cb cb;
2217                 init_all_refs_cb(&cb, revs, *flags);
2218                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/tags/", &cb);
2219                 clear_ref_exclusion(&revs->ref_excludes);
2220         } else if (skip_prefix(arg, "--remotes=", &optarg)) {
2221                 struct all_refs_cb cb;
2222                 init_all_refs_cb(&cb, revs, *flags);
2223                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/remotes/", &cb);
2224                 clear_ref_exclusion(&revs->ref_excludes);
2225         } else if (!strcmp(arg, "--reflog")) {
2226                 add_reflogs_to_pending(revs, *flags);
2227         } else if (!strcmp(arg, "--indexed-objects")) {
2228                 add_index_objects_to_pending(revs, *flags);
2229         } else if (!strcmp(arg, "--not")) {
2230                 *flags ^= UNINTERESTING | BOTTOM;
2231         } else if (!strcmp(arg, "--no-walk")) {
2232                 revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2233         } else if (skip_prefix(arg, "--no-walk=", &optarg)) {
2234                 /*
2235                  * Detached form ("--no-walk X" as opposed to "--no-walk=X")
2236                  * not allowed, since the argument is optional.
2237                  */
2238                 if (!strcmp(optarg, "sorted"))
2239                         revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2240                 else if (!strcmp(optarg, "unsorted"))
2241                         revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
2242                 else
2243                         return error("invalid argument to --no-walk");
2244         } else if (!strcmp(arg, "--do-walk")) {
2245                 revs->no_walk = 0;
2246         } else if (!strcmp(arg, "--single-worktree")) {
2247                 revs->single_worktree = 1;
2248         } else {
2249                 return 0;
2250         }
2251
2252         return 1;
2253 }
2254
2255 static void NORETURN diagnose_missing_default(const char *def)
2256 {
2257         int flags;
2258         const char *refname;
2259
2260         refname = resolve_ref_unsafe(def, 0, NULL, &flags);
2261         if (!refname || !(flags & REF_ISSYMREF) || (flags & REF_ISBROKEN))
2262                 die(_("your current branch appears to be broken"));
2263
2264         skip_prefix(refname, "refs/heads/", &refname);
2265         die(_("your current branch '%s' does not have any commits yet"),
2266             refname);
2267 }
2268
2269 /*
2270  * Parse revision information, filling in the "rev_info" structure,
2271  * and removing the used arguments from the argument list.
2272  *
2273  * Returns the number of arguments left that weren't recognized
2274  * (which are also moved to the head of the argument list)
2275  */
2276 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
2277 {
2278         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0, revarg_opt;
2279         struct argv_array prune_data = ARGV_ARRAY_INIT;
2280         const char *submodule = NULL;
2281
2282         if (opt)
2283                 submodule = opt->submodule;
2284
2285         /* First, search for "--" */
2286         if (opt && opt->assume_dashdash) {
2287                 seen_dashdash = 1;
2288         } else {
2289                 seen_dashdash = 0;
2290                 for (i = 1; i < argc; i++) {
2291                         const char *arg = argv[i];
2292                         if (strcmp(arg, "--"))
2293                                 continue;
2294                         argv[i] = NULL;
2295                         argc = i;
2296                         if (argv[i + 1])
2297                                 argv_array_pushv(&prune_data, argv + i + 1);
2298                         seen_dashdash = 1;
2299                         break;
2300                 }
2301         }
2302
2303         /* Second, deal with arguments and options */
2304         flags = 0;
2305         revarg_opt = opt ? opt->revarg_opt : 0;
2306         if (seen_dashdash)
2307                 revarg_opt |= REVARG_CANNOT_BE_FILENAME;
2308         read_from_stdin = 0;
2309         for (left = i = 1; i < argc; i++) {
2310                 const char *arg = argv[i];
2311                 if (*arg == '-') {
2312                         int opts;
2313
2314                         opts = handle_revision_pseudo_opt(submodule,
2315                                                 revs, argc - i, argv + i,
2316                                                 &flags);
2317                         if (opts > 0) {
2318                                 i += opts - 1;
2319                                 continue;
2320                         }
2321
2322                         if (!strcmp(arg, "--stdin")) {
2323                                 if (revs->disable_stdin) {
2324                                         argv[left++] = arg;
2325                                         continue;
2326                                 }
2327                                 if (read_from_stdin++)
2328                                         die("--stdin given twice?");
2329                                 read_revisions_from_stdin(revs, &prune_data);
2330                                 continue;
2331                         }
2332
2333                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
2334                         if (opts > 0) {
2335                                 i += opts - 1;
2336                                 continue;
2337                         }
2338                         if (opts < 0)
2339                                 exit(128);
2340                         continue;
2341                 }
2342
2343
2344                 if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
2345                         int j;
2346                         if (seen_dashdash || *arg == '^')
2347                                 die("bad revision '%s'", arg);
2348
2349                         /* If we didn't have a "--":
2350                          * (1) all filenames must exist;
2351                          * (2) all rev-args must not be interpretable
2352                          *     as a valid filename.
2353                          * but the latter we have checked in the main loop.
2354                          */
2355                         for (j = i; j < argc; j++)
2356                                 verify_filename(revs->prefix, argv[j], j == i);
2357
2358                         argv_array_pushv(&prune_data, argv + i);
2359                         break;
2360                 }
2361                 else
2362                         got_rev_arg = 1;
2363         }
2364
2365         if (prune_data.argc) {
2366                 /*
2367                  * If we need to introduce the magic "a lone ':' means no
2368                  * pathspec whatsoever", here is the place to do so.
2369                  *
2370                  * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
2371                  *      prune_data.nr = 0;
2372                  *      prune_data.alloc = 0;
2373                  *      free(prune_data.path);
2374                  *      prune_data.path = NULL;
2375                  * } else {
2376                  *      terminate prune_data.alloc with NULL and
2377                  *      call init_pathspec() to set revs->prune_data here.
2378                  * }
2379                  */
2380                 parse_pathspec(&revs->prune_data, 0, 0,
2381                                revs->prefix, prune_data.argv);
2382         }
2383         argv_array_clear(&prune_data);
2384
2385         if (revs->def == NULL)
2386                 revs->def = opt ? opt->def : NULL;
2387         if (opt && opt->tweak)
2388                 opt->tweak(revs, opt);
2389         if (revs->show_merge)
2390                 prepare_show_merge(revs);
2391         if (revs->def && !revs->pending.nr && !revs->rev_input_given && !got_rev_arg) {
2392                 struct object_id oid;
2393                 struct object *object;
2394                 struct object_context oc;
2395                 if (get_oid_with_context(revs->def, 0, &oid, &oc))
2396                         diagnose_missing_default(revs->def);
2397                 object = get_reference(revs, revs->def, &oid, 0);
2398                 add_pending_object_with_mode(revs, object, revs->def, oc.mode);
2399         }
2400
2401         /* Did the user ask for any diff output? Run the diff! */
2402         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
2403                 revs->diff = 1;
2404
2405         /* Pickaxe, diff-filter and rename following need diffs */
2406         if (revs->diffopt.pickaxe ||
2407             revs->diffopt.filter ||
2408             revs->diffopt.flags.follow_renames)
2409                 revs->diff = 1;
2410
2411         if (revs->topo_order)
2412                 revs->limited = 1;
2413
2414         if (revs->prune_data.nr) {
2415                 copy_pathspec(&revs->pruning.pathspec, &revs->prune_data);
2416                 /* Can't prune commits with rename following: the paths change.. */
2417                 if (!revs->diffopt.flags.follow_renames)
2418                         revs->prune = 1;
2419                 if (!revs->full_diff)
2420                         copy_pathspec(&revs->diffopt.pathspec,
2421                                       &revs->prune_data);
2422         }
2423         if (revs->combine_merges)
2424                 revs->ignore_merges = 0;
2425         revs->diffopt.abbrev = revs->abbrev;
2426
2427         if (revs->line_level_traverse) {
2428                 revs->limited = 1;
2429                 revs->topo_order = 1;
2430         }
2431
2432         diff_setup_done(&revs->diffopt);
2433
2434         grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
2435                                  &revs->grep_filter);
2436         compile_grep_patterns(&revs->grep_filter);
2437
2438         if (revs->reverse && revs->reflog_info)
2439                 die("cannot combine --reverse with --walk-reflogs");
2440         if (revs->reflog_info && revs->limited)
2441                 die("cannot combine --walk-reflogs with history-limiting options");
2442         if (revs->rewrite_parents && revs->children.name)
2443                 die("cannot combine --parents and --children");
2444
2445         /*
2446          * Limitations on the graph functionality
2447          */
2448         if (revs->reverse && revs->graph)
2449                 die("cannot combine --reverse with --graph");
2450
2451         if (revs->reflog_info && revs->graph)
2452                 die("cannot combine --walk-reflogs with --graph");
2453         if (revs->no_walk && revs->graph)
2454                 die("cannot combine --no-walk with --graph");
2455         if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
2456                 die("cannot use --grep-reflog without --walk-reflogs");
2457
2458         if (revs->first_parent_only && revs->bisect)
2459                 die(_("--first-parent is incompatible with --bisect"));
2460
2461         if (revs->expand_tabs_in_log < 0)
2462                 revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;
2463
2464         return left;
2465 }
2466
2467 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
2468 {
2469         struct commit_list *l = xcalloc(1, sizeof(*l));
2470
2471         l->item = child;
2472         l->next = add_decoration(&revs->children, &parent->object, l);
2473 }
2474
2475 static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
2476 {
2477         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2478         struct commit_list **pp, *p;
2479         int surviving_parents;
2480
2481         /* Examine existing parents while marking ones we have seen... */
2482         pp = &commit->parents;
2483         surviving_parents = 0;
2484         while ((p = *pp) != NULL) {
2485                 struct commit *parent = p->item;
2486                 if (parent->object.flags & TMP_MARK) {
2487                         *pp = p->next;
2488                         if (ts)
2489                                 compact_treesame(revs, commit, surviving_parents);
2490                         continue;
2491                 }
2492                 parent->object.flags |= TMP_MARK;
2493                 surviving_parents++;
2494                 pp = &p->next;
2495         }
2496         /* clear the temporary mark */
2497         for (p = commit->parents; p; p = p->next) {
2498                 p->item->object.flags &= ~TMP_MARK;
2499         }
2500         /* no update_treesame() - removing duplicates can't affect TREESAME */
2501         return surviving_parents;
2502 }
2503
2504 struct merge_simplify_state {
2505         struct commit *simplified;
2506 };
2507
2508 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
2509 {
2510         struct merge_simplify_state *st;
2511
2512         st = lookup_decoration(&revs->merge_simplification, &commit->object);
2513         if (!st) {
2514                 st = xcalloc(1, sizeof(*st));
2515                 add_decoration(&revs->merge_simplification, &commit->object, st);
2516         }
2517         return st;
2518 }
2519
2520 static int mark_redundant_parents(struct rev_info *revs, struct commit *commit)
2521 {
2522         struct commit_list *h = reduce_heads(commit->parents);
2523         int i = 0, marked = 0;
2524         struct commit_list *po, *pn;
2525
2526         /* Want these for sanity-checking only */
2527         int orig_cnt = commit_list_count(commit->parents);
2528         int cnt = commit_list_count(h);
2529
2530         /*
2531          * Not ready to remove items yet, just mark them for now, based
2532          * on the output of reduce_heads(). reduce_heads outputs the reduced
2533          * set in its original order, so this isn't too hard.
2534          */
2535         po = commit->parents;
2536         pn = h;
2537         while (po) {
2538                 if (pn && po->item == pn->item) {
2539                         pn = pn->next;
2540                         i++;
2541                 } else {
2542                         po->item->object.flags |= TMP_MARK;
2543                         marked++;
2544                 }
2545                 po=po->next;
2546         }
2547
2548         if (i != cnt || cnt+marked != orig_cnt)
2549                 die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
2550
2551         free_commit_list(h);
2552
2553         return marked;
2554 }
2555
2556 static int mark_treesame_root_parents(struct rev_info *revs, struct commit *commit)
2557 {
2558         struct commit_list *p;
2559         int marked = 0;
2560
2561         for (p = commit->parents; p; p = p->next) {
2562                 struct commit *parent = p->item;
2563                 if (!parent->parents && (parent->object.flags & TREESAME)) {
2564                         parent->object.flags |= TMP_MARK;
2565                         marked++;
2566                 }
2567         }
2568
2569         return marked;
2570 }
2571
2572 /*
2573  * Awkward naming - this means one parent we are TREESAME to.
2574  * cf mark_treesame_root_parents: root parents that are TREESAME (to an
2575  * empty tree). Better name suggestions?
2576  */
2577 static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
2578 {
2579         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2580         struct commit *unmarked = NULL, *marked = NULL;
2581         struct commit_list *p;
2582         unsigned n;
2583
2584         for (p = commit->parents, n = 0; p; p = p->next, n++) {
2585                 if (ts->treesame[n]) {
2586                         if (p->item->object.flags & TMP_MARK) {
2587                                 if (!marked)
2588                                         marked = p->item;
2589                         } else {
2590                                 if (!unmarked) {
2591                                         unmarked = p->item;
2592                                         break;
2593                                 }
2594                         }
2595                 }
2596         }
2597
2598         /*
2599          * If we are TREESAME to a marked-for-deletion parent, but not to any
2600          * unmarked parents, unmark the first TREESAME parent. This is the
2601          * parent that the default simplify_history==1 scan would have followed,
2602          * and it doesn't make sense to omit that path when asking for a
2603          * simplified full history. Retaining it improves the chances of
2604          * understanding odd missed merges that took an old version of a file.
2605          *
2606          * Example:
2607          *
2608          *   I--------*X       A modified the file, but mainline merge X used
2609          *    \       /        "-s ours", so took the version from I. X is
2610          *     `-*A--'         TREESAME to I and !TREESAME to A.
2611          *
2612          * Default log from X would produce "I". Without this check,
2613          * --full-history --simplify-merges would produce "I-A-X", showing
2614          * the merge commit X and that it changed A, but not making clear that
2615          * it had just taken the I version. With this check, the topology above
2616          * is retained.
2617          *
2618          * Note that it is possible that the simplification chooses a different
2619          * TREESAME parent from the default, in which case this test doesn't
2620          * activate, and we _do_ drop the default parent. Example:
2621          *
2622          *   I------X         A modified the file, but it was reverted in B,
2623          *    \    /          meaning mainline merge X is TREESAME to both
2624          *    *A-*B           parents.
2625          *
2626          * Default log would produce "I" by following the first parent;
2627          * --full-history --simplify-merges will produce "I-A-B". But this is a
2628          * reasonable result - it presents a logical full history leading from
2629          * I to X, and X is not an important merge.
2630          */
2631         if (!unmarked && marked) {
2632                 marked->object.flags &= ~TMP_MARK;
2633                 return 1;
2634         }
2635
2636         return 0;
2637 }
2638
2639 static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
2640 {
2641         struct commit_list **pp, *p;
2642         int nth_parent, removed = 0;
2643
2644         pp = &commit->parents;
2645         nth_parent = 0;
2646         while ((p = *pp) != NULL) {
2647                 struct commit *parent = p->item;
2648                 if (parent->object.flags & TMP_MARK) {
2649                         parent->object.flags &= ~TMP_MARK;
2650                         *pp = p->next;
2651                         free(p);
2652                         removed++;
2653                         compact_treesame(revs, commit, nth_parent);
2654                         continue;
2655                 }
2656                 pp = &p->next;
2657                 nth_parent++;
2658         }
2659
2660         /* Removing parents can only increase TREESAMEness */
2661         if (removed && !(commit->object.flags & TREESAME))
2662                 update_treesame(revs, commit);
2663
2664         return nth_parent;
2665 }
2666
2667 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
2668 {
2669         struct commit_list *p;
2670         struct commit *parent;
2671         struct merge_simplify_state *st, *pst;
2672         int cnt;
2673
2674         st = locate_simplify_state(revs, commit);
2675
2676         /*
2677          * Have we handled this one?
2678          */
2679         if (st->simplified)
2680                 return tail;
2681
2682         /*
2683          * An UNINTERESTING commit simplifies to itself, so does a
2684          * root commit.  We do not rewrite parents of such commit
2685          * anyway.
2686          */
2687         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
2688                 st->simplified = commit;
2689                 return tail;
2690         }
2691
2692         /*
2693          * Do we know what commit all of our parents that matter
2694          * should be rewritten to?  Otherwise we are not ready to
2695          * rewrite this one yet.
2696          */
2697         for (cnt = 0, p = commit->parents; p; p = p->next) {
2698                 pst = locate_simplify_state(revs, p->item);
2699                 if (!pst->simplified) {
2700                         tail = &commit_list_insert(p->item, tail)->next;
2701                         cnt++;
2702                 }
2703                 if (revs->first_parent_only)
2704                         break;
2705         }
2706         if (cnt) {
2707                 tail = &commit_list_insert(commit, tail)->next;
2708                 return tail;
2709         }
2710
2711         /*
2712          * Rewrite our list of parents. Note that this cannot
2713          * affect our TREESAME flags in any way - a commit is
2714          * always TREESAME to its simplification.
2715          */
2716         for (p = commit->parents; p; p = p->next) {
2717                 pst = locate_simplify_state(revs, p->item);
2718                 p->item = pst->simplified;
2719                 if (revs->first_parent_only)
2720                         break;
2721         }
2722
2723         if (revs->first_parent_only)
2724                 cnt = 1;
2725         else
2726                 cnt = remove_duplicate_parents(revs, commit);
2727
2728         /*
2729          * It is possible that we are a merge and one side branch
2730          * does not have any commit that touches the given paths;
2731          * in such a case, the immediate parent from that branch
2732          * will be rewritten to be the merge base.
2733          *
2734          *      o----X          X: the commit we are looking at;
2735          *     /    /           o: a commit that touches the paths;
2736          * ---o----'
2737          *
2738          * Further, a merge of an independent branch that doesn't
2739          * touch the path will reduce to a treesame root parent:
2740          *
2741          *  ----o----X          X: the commit we are looking at;
2742          *          /           o: a commit that touches the paths;
2743          *         r            r: a root commit not touching the paths
2744          *
2745          * Detect and simplify both cases.
2746          */
2747         if (1 < cnt) {
2748                 int marked = mark_redundant_parents(revs, commit);
2749                 marked += mark_treesame_root_parents(revs, commit);
2750                 if (marked)
2751                         marked -= leave_one_treesame_to_parent(revs, commit);
2752                 if (marked)
2753                         cnt = remove_marked_parents(revs, commit);
2754         }
2755
2756         /*
2757          * A commit simplifies to itself if it is a root, if it is
2758          * UNINTERESTING, if it touches the given paths, or if it is a
2759          * merge and its parents don't simplify to one relevant commit
2760          * (the first two cases are already handled at the beginning of
2761          * this function).
2762          *
2763          * Otherwise, it simplifies to what its sole relevant parent
2764          * simplifies to.
2765          */
2766         if (!cnt ||
2767             (commit->object.flags & UNINTERESTING) ||
2768             !(commit->object.flags & TREESAME) ||
2769             (parent = one_relevant_parent(revs, commit->parents)) == NULL)
2770                 st->simplified = commit;
2771         else {
2772                 pst = locate_simplify_state(revs, parent);
2773                 st->simplified = pst->simplified;
2774         }
2775         return tail;
2776 }
2777
2778 static void simplify_merges(struct rev_info *revs)
2779 {
2780         struct commit_list *list, *next;
2781         struct commit_list *yet_to_do, **tail;
2782         struct commit *commit;
2783
2784         if (!revs->prune)
2785                 return;
2786
2787         /* feed the list reversed */
2788         yet_to_do = NULL;
2789         for (list = revs->commits; list; list = next) {
2790                 commit = list->item;
2791                 next = list->next;
2792                 /*
2793                  * Do not free(list) here yet; the original list
2794                  * is used later in this function.
2795                  */
2796                 commit_list_insert(commit, &yet_to_do);
2797         }
2798         while (yet_to_do) {
2799                 list = yet_to_do;
2800                 yet_to_do = NULL;
2801                 tail = &yet_to_do;
2802                 while (list) {
2803                         commit = pop_commit(&list);
2804                         tail = simplify_one(revs, commit, tail);
2805                 }
2806         }
2807
2808         /* clean up the result, removing the simplified ones */
2809         list = revs->commits;
2810         revs->commits = NULL;
2811         tail = &revs->commits;
2812         while (list) {
2813                 struct merge_simplify_state *st;
2814
2815                 commit = pop_commit(&list);
2816                 st = locate_simplify_state(revs, commit);
2817                 if (st->simplified == commit)
2818                         tail = &commit_list_insert(commit, tail)->next;
2819         }
2820 }
2821
2822 static void set_children(struct rev_info *revs)
2823 {
2824         struct commit_list *l;
2825         for (l = revs->commits; l; l = l->next) {
2826                 struct commit *commit = l->item;
2827                 struct commit_list *p;
2828
2829                 for (p = commit->parents; p; p = p->next)
2830                         add_child(revs, p->item, commit);
2831         }
2832 }
2833
2834 void reset_revision_walk(void)
2835 {
2836         clear_object_flags(SEEN | ADDED | SHOWN);
2837 }
2838
2839 int prepare_revision_walk(struct rev_info *revs)
2840 {
2841         int i;
2842         struct object_array old_pending;
2843         struct commit_list **next = &revs->commits;
2844
2845         memcpy(&old_pending, &revs->pending, sizeof(old_pending));
2846         revs->pending.nr = 0;
2847         revs->pending.alloc = 0;
2848         revs->pending.objects = NULL;
2849         for (i = 0; i < old_pending.nr; i++) {
2850                 struct object_array_entry *e = old_pending.objects + i;
2851                 struct commit *commit = handle_commit(revs, e);
2852                 if (commit) {
2853                         if (!(commit->object.flags & SEEN)) {
2854                                 commit->object.flags |= SEEN;
2855                                 next = commit_list_append(commit, next);
2856                         }
2857                 }
2858         }
2859         object_array_clear(&old_pending);
2860
2861         /* Signal whether we need per-parent treesame decoration */
2862         if (revs->simplify_merges ||
2863             (revs->limited && limiting_can_increase_treesame(revs)))
2864                 revs->treesame.name = "treesame";
2865
2866         if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
2867                 commit_list_sort_by_date(&revs->commits);
2868         if (revs->no_walk)
2869                 return 0;
2870         if (revs->limited)
2871                 if (limit_list(revs) < 0)
2872                         return -1;
2873         if (revs->topo_order)
2874                 sort_in_topological_order(&revs->commits, revs->sort_order);
2875         if (revs->line_level_traverse)
2876                 line_log_filter(revs);
2877         if (revs->simplify_merges)
2878                 simplify_merges(revs);
2879         if (revs->children.name)
2880                 set_children(revs);
2881         return 0;
2882 }
2883
2884 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
2885 {
2886         struct commit_list *cache = NULL;
2887
2888         for (;;) {
2889                 struct commit *p = *pp;
2890                 if (!revs->limited)
2891                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
2892                                 return rewrite_one_error;
2893                 if (p->object.flags & UNINTERESTING)
2894                         return rewrite_one_ok;
2895                 if (!(p->object.flags & TREESAME))
2896                         return rewrite_one_ok;
2897                 if (!p->parents)
2898                         return rewrite_one_noparents;
2899                 if ((p = one_relevant_parent(revs, p->parents)) == NULL)
2900                         return rewrite_one_ok;
2901                 *pp = p;
2902         }
2903 }
2904
2905 int rewrite_parents(struct rev_info *revs, struct commit *commit,
2906         rewrite_parent_fn_t rewrite_parent)
2907 {
2908         struct commit_list **pp = &commit->parents;
2909         while (*pp) {
2910                 struct commit_list *parent = *pp;
2911                 switch (rewrite_parent(revs, &parent->item)) {
2912                 case rewrite_one_ok:
2913                         break;
2914                 case rewrite_one_noparents:
2915                         *pp = parent->next;
2916                         continue;
2917                 case rewrite_one_error:
2918                         return -1;
2919                 }
2920                 pp = &parent->next;
2921         }
2922         remove_duplicate_parents(revs, commit);
2923         return 0;
2924 }
2925
2926 static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
2927 {
2928         char *person, *endp;
2929         size_t len, namelen, maillen;
2930         const char *name;
2931         const char *mail;
2932         struct ident_split ident;
2933
2934         person = strstr(buf->buf, what);
2935         if (!person)
2936                 return 0;
2937
2938         person += strlen(what);
2939         endp = strchr(person, '\n');
2940         if (!endp)
2941                 return 0;
2942
2943         len = endp - person;
2944
2945         if (split_ident_line(&ident, person, len))
2946                 return 0;
2947
2948         mail = ident.mail_begin;
2949         maillen = ident.mail_end - ident.mail_begin;
2950         name = ident.name_begin;
2951         namelen = ident.name_end - ident.name_begin;
2952
2953         if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
2954                 struct strbuf namemail = STRBUF_INIT;
2955
2956                 strbuf_addf(&namemail, "%.*s <%.*s>",
2957                             (int)namelen, name, (int)maillen, mail);
2958
2959                 strbuf_splice(buf, ident.name_begin - buf->buf,
2960                               ident.mail_end - ident.name_begin + 1,
2961                               namemail.buf, namemail.len);
2962
2963                 strbuf_release(&namemail);
2964
2965                 return 1;
2966         }
2967
2968         return 0;
2969 }
2970
2971 static int commit_match(struct commit *commit, struct rev_info *opt)
2972 {
2973         int retval;
2974         const char *encoding;
2975         const char *message;
2976         struct strbuf buf = STRBUF_INIT;
2977
2978         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
2979                 return 1;
2980
2981         /* Prepend "fake" headers as needed */
2982         if (opt->grep_filter.use_reflog_filter) {
2983                 strbuf_addstr(&buf, "reflog ");
2984                 get_reflog_message(&buf, opt->reflog_info);
2985                 strbuf_addch(&buf, '\n');
2986         }
2987
2988         /*
2989          * We grep in the user's output encoding, under the assumption that it
2990          * is the encoding they are most likely to write their grep pattern
2991          * for. In addition, it means we will match the "notes" encoding below,
2992          * so we will not end up with a buffer that has two different encodings
2993          * in it.
2994          */
2995         encoding = get_log_output_encoding();
2996         message = logmsg_reencode(commit, NULL, encoding);
2997
2998         /* Copy the commit to temporary if we are using "fake" headers */
2999         if (buf.len)
3000                 strbuf_addstr(&buf, message);
3001
3002         if (opt->grep_filter.header_list && opt->mailmap) {
3003                 if (!buf.len)
3004                         strbuf_addstr(&buf, message);
3005
3006                 commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
3007                 commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
3008         }
3009
3010         /* Append "fake" message parts as needed */
3011         if (opt->show_notes) {
3012                 if (!buf.len)
3013                         strbuf_addstr(&buf, message);
3014                 format_display_notes(&commit->object.oid, &buf, encoding, 1);
3015         }
3016
3017         /*
3018          * Find either in the original commit message, or in the temporary.
3019          * Note that we cast away the constness of "message" here. It is
3020          * const because it may come from the cached commit buffer. That's OK,
3021          * because we know that it is modifiable heap memory, and that while
3022          * grep_buffer may modify it for speed, it will restore any
3023          * changes before returning.
3024          */
3025         if (buf.len)
3026                 retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
3027         else
3028                 retval = grep_buffer(&opt->grep_filter,
3029                                      (char *)message, strlen(message));
3030         strbuf_release(&buf);
3031         unuse_commit_buffer(commit, message);
3032         return opt->invert_grep ? !retval : retval;
3033 }
3034
3035 static inline int want_ancestry(const struct rev_info *revs)
3036 {
3037         return (revs->rewrite_parents || revs->children.name);
3038 }
3039
3040 /*
3041  * Return a timestamp to be used for --since/--until comparisons for this
3042  * commit, based on the revision options.
3043  */
3044 static timestamp_t comparison_date(const struct rev_info *revs,
3045                                    struct commit *commit)
3046 {
3047         return revs->reflog_info ?
3048                 get_reflog_timestamp(revs->reflog_info) :
3049                 commit->date;
3050 }
3051
3052 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
3053 {
3054         if (commit->object.flags & SHOWN)
3055                 return commit_ignore;
3056         if (revs->unpacked && has_sha1_pack(commit->object.oid.hash))
3057                 return commit_ignore;
3058         if (commit->object.flags & UNINTERESTING)
3059                 return commit_ignore;
3060         if (revs->min_age != -1 &&
3061             comparison_date(revs, commit) > revs->min_age)
3062                         return commit_ignore;
3063         if (revs->min_parents || (revs->max_parents >= 0)) {
3064                 int n = commit_list_count(commit->parents);
3065                 if ((n < revs->min_parents) ||
3066                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
3067                         return commit_ignore;
3068         }
3069         if (!commit_match(commit, revs))
3070                 return commit_ignore;
3071         if (revs->prune && revs->dense) {
3072                 /* Commit without changes? */
3073                 if (commit->object.flags & TREESAME) {
3074                         int n;
3075                         struct commit_list *p;
3076                         /* drop merges unless we want parenthood */
3077                         if (!want_ancestry(revs))
3078                                 return commit_ignore;
3079                         /*
3080                          * If we want ancestry, then need to keep any merges
3081                          * between relevant commits to tie together topology.
3082                          * For consistency with TREESAME and simplification
3083                          * use "relevant" here rather than just INTERESTING,
3084                          * to treat bottom commit(s) as part of the topology.
3085                          */
3086                         for (n = 0, p = commit->parents; p; p = p->next)
3087                                 if (relevant_commit(p->item))
3088                                         if (++n >= 2)
3089                                                 return commit_show;
3090                         return commit_ignore;
3091                 }
3092         }
3093         return commit_show;
3094 }
3095
3096 define_commit_slab(saved_parents, struct commit_list *);
3097
3098 #define EMPTY_PARENT_LIST ((struct commit_list *)-1)
3099
3100 /*
3101  * You may only call save_parents() once per commit (this is checked
3102  * for non-root commits).
3103  */
3104 static void save_parents(struct rev_info *revs, struct commit *commit)
3105 {
3106         struct commit_list **pp;
3107
3108         if (!revs->saved_parents_slab) {
3109                 revs->saved_parents_slab = xmalloc(sizeof(struct saved_parents));
3110                 init_saved_parents(revs->saved_parents_slab);
3111         }
3112
3113         pp = saved_parents_at(revs->saved_parents_slab, commit);
3114
3115         /*
3116          * When walking with reflogs, we may visit the same commit
3117          * several times: once for each appearance in the reflog.
3118          *
3119          * In this case, save_parents() will be called multiple times.
3120          * We want to keep only the first set of parents.  We need to
3121          * store a sentinel value for an empty (i.e., NULL) parent
3122          * list to distinguish it from a not-yet-saved list, however.
3123          */
3124         if (*pp)
3125                 return;
3126         if (commit->parents)
3127                 *pp = copy_commit_list(commit->parents);
3128         else
3129                 *pp = EMPTY_PARENT_LIST;
3130 }
3131
3132 static void free_saved_parents(struct rev_info *revs)
3133 {
3134         if (revs->saved_parents_slab)
3135                 clear_saved_parents(revs->saved_parents_slab);
3136 }
3137
3138 struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit)
3139 {
3140         struct commit_list *parents;
3141
3142         if (!revs->saved_parents_slab)
3143                 return commit->parents;
3144
3145         parents = *saved_parents_at(revs->saved_parents_slab, commit);
3146         if (parents == EMPTY_PARENT_LIST)
3147                 return NULL;
3148         return parents;
3149 }
3150
3151 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
3152 {
3153         enum commit_action action = get_commit_action(revs, commit);
3154
3155         if (action == commit_show &&
3156             revs->prune && revs->dense && want_ancestry(revs)) {
3157                 /*
3158                  * --full-diff on simplified parents is no good: it
3159                  * will show spurious changes from the commits that
3160                  * were elided.  So we save the parents on the side
3161                  * when --full-diff is in effect.
3162                  */
3163                 if (revs->full_diff)
3164                         save_parents(revs, commit);
3165                 if (rewrite_parents(revs, commit, rewrite_one) < 0)
3166                         return commit_error;
3167         }
3168         return action;
3169 }
3170
3171 static void track_linear(struct rev_info *revs, struct commit *commit)
3172 {
3173         if (revs->track_first_time) {
3174                 revs->linear = 1;
3175                 revs->track_first_time = 0;
3176         } else {
3177                 struct commit_list *p;
3178                 for (p = revs->previous_parents; p; p = p->next)
3179                         if (p->item == NULL || /* first commit */
3180                             !oidcmp(&p->item->object.oid, &commit->object.oid))
3181                                 break;
3182                 revs->linear = p != NULL;
3183         }
3184         if (revs->reverse) {
3185                 if (revs->linear)
3186                         commit->object.flags |= TRACK_LINEAR;
3187         }
3188         free_commit_list(revs->previous_parents);
3189         revs->previous_parents = copy_commit_list(commit->parents);
3190 }
3191
3192 static struct commit *get_revision_1(struct rev_info *revs)
3193 {
3194         while (1) {
3195                 struct commit *commit;
3196
3197                 if (revs->reflog_info)
3198                         commit = next_reflog_entry(revs->reflog_info);
3199                 else
3200                         commit = pop_commit(&revs->commits);
3201
3202                 if (!commit)
3203                         return NULL;
3204
3205                 if (revs->reflog_info)
3206                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
3207
3208                 /*
3209                  * If we haven't done the list limiting, we need to look at
3210                  * the parents here. We also need to do the date-based limiting
3211                  * that we'd otherwise have done in limit_list().
3212                  */
3213                 if (!revs->limited) {
3214                         if (revs->max_age != -1 &&
3215                             comparison_date(revs, commit) < revs->max_age)
3216                                 continue;
3217
3218                         if (revs->reflog_info)
3219                                 try_to_simplify_commit(revs, commit);
3220                         else if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0) {
3221                                 if (!revs->ignore_missing_links)
3222                                         die("Failed to traverse parents of commit %s",
3223                                                 oid_to_hex(&commit->object.oid));
3224                         }
3225                 }
3226
3227                 switch (simplify_commit(revs, commit)) {
3228                 case commit_ignore:
3229                         continue;
3230                 case commit_error:
3231                         die("Failed to simplify parents of commit %s",
3232                             oid_to_hex(&commit->object.oid));
3233                 default:
3234                         if (revs->track_linear)
3235                                 track_linear(revs, commit);
3236                         return commit;
3237                 }
3238         }
3239 }
3240
3241 /*
3242  * Return true for entries that have not yet been shown.  (This is an
3243  * object_array_each_func_t.)
3244  */
3245 static int entry_unshown(struct object_array_entry *entry, void *cb_data_unused)
3246 {
3247         return !(entry->item->flags & SHOWN);
3248 }
3249
3250 /*
3251  * If array is on the verge of a realloc, garbage-collect any entries
3252  * that have already been shown to try to free up some space.
3253  */
3254 static void gc_boundary(struct object_array *array)
3255 {
3256         if (array->nr == array->alloc)
3257                 object_array_filter(array, entry_unshown, NULL);
3258 }
3259
3260 static void create_boundary_commit_list(struct rev_info *revs)
3261 {
3262         unsigned i;
3263         struct commit *c;
3264         struct object_array *array = &revs->boundary_commits;
3265         struct object_array_entry *objects = array->objects;
3266
3267         /*
3268          * If revs->commits is non-NULL at this point, an error occurred in
3269          * get_revision_1().  Ignore the error and continue printing the
3270          * boundary commits anyway.  (This is what the code has always
3271          * done.)
3272          */
3273         if (revs->commits) {
3274                 free_commit_list(revs->commits);
3275                 revs->commits = NULL;
3276         }
3277
3278         /*
3279          * Put all of the actual boundary commits from revs->boundary_commits
3280          * into revs->commits
3281          */
3282         for (i = 0; i < array->nr; i++) {
3283                 c = (struct commit *)(objects[i].item);
3284                 if (!c)
3285                         continue;
3286                 if (!(c->object.flags & CHILD_SHOWN))
3287                         continue;
3288                 if (c->object.flags & (SHOWN | BOUNDARY))
3289                         continue;
3290                 c->object.flags |= BOUNDARY;
3291                 commit_list_insert(c, &revs->commits);
3292         }
3293
3294         /*
3295          * If revs->topo_order is set, sort the boundary commits
3296          * in topological order
3297          */
3298         sort_in_topological_order(&revs->commits, revs->sort_order);
3299 }
3300
3301 static struct commit *get_revision_internal(struct rev_info *revs)
3302 {
3303         struct commit *c = NULL;
3304         struct commit_list *l;
3305
3306         if (revs->boundary == 2) {
3307                 /*
3308                  * All of the normal commits have already been returned,
3309                  * and we are now returning boundary commits.
3310                  * create_boundary_commit_list() has populated
3311                  * revs->commits with the remaining commits to return.
3312                  */
3313                 c = pop_commit(&revs->commits);
3314                 if (c)
3315                         c->object.flags |= SHOWN;
3316                 return c;
3317         }
3318
3319         /*
3320          * If our max_count counter has reached zero, then we are done. We
3321          * don't simply return NULL because we still might need to show
3322          * boundary commits. But we want to avoid calling get_revision_1, which
3323          * might do a considerable amount of work finding the next commit only
3324          * for us to throw it away.
3325          *
3326          * If it is non-zero, then either we don't have a max_count at all
3327          * (-1), or it is still counting, in which case we decrement.
3328          */
3329         if (revs->max_count) {
3330                 c = get_revision_1(revs);
3331                 if (c) {
3332                         while (revs->skip_count > 0) {
3333                                 revs->skip_count--;
3334                                 c = get_revision_1(revs);
3335                                 if (!c)
3336                                         break;
3337                         }
3338                 }
3339
3340                 if (revs->max_count > 0)
3341                         revs->max_count--;
3342         }
3343
3344         if (c)
3345                 c->object.flags |= SHOWN;
3346
3347         if (!revs->boundary)
3348                 return c;
3349
3350         if (!c) {
3351                 /*
3352                  * get_revision_1() runs out the commits, and
3353                  * we are done computing the boundaries.
3354                  * switch to boundary commits output mode.
3355                  */
3356                 revs->boundary = 2;
3357
3358                 /*
3359                  * Update revs->commits to contain the list of
3360                  * boundary commits.
3361                  */
3362                 create_boundary_commit_list(revs);
3363
3364                 return get_revision_internal(revs);
3365         }
3366
3367         /*
3368          * boundary commits are the commits that are parents of the
3369          * ones we got from get_revision_1() but they themselves are
3370          * not returned from get_revision_1().  Before returning
3371          * 'c', we need to mark its parents that they could be boundaries.
3372          */
3373
3374         for (l = c->parents; l; l = l->next) {
3375                 struct object *p;
3376                 p = &(l->item->object);
3377                 if (p->flags & (CHILD_SHOWN | SHOWN))
3378                         continue;
3379                 p->flags |= CHILD_SHOWN;
3380                 gc_boundary(&revs->boundary_commits);
3381                 add_object_array(p, NULL, &revs->boundary_commits);
3382         }
3383
3384         return c;
3385 }
3386
3387 struct commit *get_revision(struct rev_info *revs)
3388 {
3389         struct commit *c;
3390         struct commit_list *reversed;
3391
3392         if (revs->reverse) {
3393                 reversed = NULL;
3394                 while ((c = get_revision_internal(revs)))
3395                         commit_list_insert(c, &reversed);
3396                 revs->commits = reversed;
3397                 revs->reverse = 0;
3398                 revs->reverse_output_stage = 1;
3399         }
3400
3401         if (revs->reverse_output_stage) {
3402                 c = pop_commit(&revs->commits);
3403                 if (revs->track_linear)
3404                         revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
3405                 return c;
3406         }
3407
3408         c = get_revision_internal(revs);
3409         if (c && revs->graph)
3410                 graph_update(revs->graph, c);
3411         if (!c) {
3412                 free_saved_parents(revs);
3413                 if (revs->previous_parents) {
3414                         free_commit_list(revs->previous_parents);
3415                         revs->previous_parents = NULL;
3416                 }
3417         }
3418         return c;
3419 }
3420
3421 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
3422 {
3423         if (commit->object.flags & BOUNDARY)
3424                 return "-";
3425         else if (commit->object.flags & UNINTERESTING)
3426                 return "^";
3427         else if (commit->object.flags & PATCHSAME)
3428                 return "=";
3429         else if (!revs || revs->left_right) {
3430                 if (commit->object.flags & SYMMETRIC_LEFT)
3431                         return "<";
3432                 else
3433                         return ">";
3434         } else if (revs->graph)
3435                 return "*";
3436         else if (revs->cherry_mark)
3437                 return "+";
3438         return "";
3439 }
3440
3441 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
3442 {
3443         char *mark = get_revision_mark(revs, commit);
3444         if (!strlen(mark))
3445                 return;
3446         fputs(mark, stdout);
3447         putchar(' ');
3448 }