Merge branch 'du/get-tar-commit-id-is-plumbing'
[git] / revision.c
1 #include "cache.h"
2 #include "object-store.h"
3 #include "tag.h"
4 #include "blob.h"
5 #include "tree.h"
6 #include "commit.h"
7 #include "diff.h"
8 #include "refs.h"
9 #include "revision.h"
10 #include "repository.h"
11 #include "graph.h"
12 #include "grep.h"
13 #include "reflog-walk.h"
14 #include "patch-ids.h"
15 #include "decorate.h"
16 #include "log-tree.h"
17 #include "string-list.h"
18 #include "line-log.h"
19 #include "mailmap.h"
20 #include "commit-slab.h"
21 #include "dir.h"
22 #include "cache-tree.h"
23 #include "bisect.h"
24 #include "packfile.h"
25 #include "worktree.h"
26 #include "argv-array.h"
27 #include "commit-reach.h"
28
29 volatile show_early_output_fn_t show_early_output;
30
31 static const char *term_bad;
32 static const char *term_good;
33
34 implement_shared_commit_slab(revision_sources, char *);
35
36 void show_object_with_name(FILE *out, struct object *obj, const char *name)
37 {
38         const char *p;
39
40         fprintf(out, "%s ", oid_to_hex(&obj->oid));
41         for (p = name; *p && *p != '\n'; p++)
42                 fputc(*p, out);
43         fputc('\n', out);
44 }
45
46 static void mark_blob_uninteresting(struct blob *blob)
47 {
48         if (!blob)
49                 return;
50         if (blob->object.flags & UNINTERESTING)
51                 return;
52         blob->object.flags |= UNINTERESTING;
53 }
54
55 static void mark_tree_contents_uninteresting(struct repository *r,
56                                              struct tree *tree)
57 {
58         struct tree_desc desc;
59         struct name_entry entry;
60
61         if (parse_tree_gently(tree, 1) < 0)
62                 return;
63
64         init_tree_desc(&desc, tree->buffer, tree->size);
65         while (tree_entry(&desc, &entry)) {
66                 switch (object_type(entry.mode)) {
67                 case OBJ_TREE:
68                         mark_tree_uninteresting(r, lookup_tree(r, entry.oid));
69                         break;
70                 case OBJ_BLOB:
71                         mark_blob_uninteresting(lookup_blob(r, entry.oid));
72                         break;
73                 default:
74                         /* Subproject commit - not in this repository */
75                         break;
76                 }
77         }
78
79         /*
80          * We don't care about the tree any more
81          * after it has been marked uninteresting.
82          */
83         free_tree_buffer(tree);
84 }
85
86 void mark_tree_uninteresting(struct repository *r, struct tree *tree)
87 {
88         struct object *obj;
89
90         if (!tree)
91                 return;
92
93         obj = &tree->object;
94         if (obj->flags & UNINTERESTING)
95                 return;
96         obj->flags |= UNINTERESTING;
97         mark_tree_contents_uninteresting(r, tree);
98 }
99
100 struct commit_stack {
101         struct commit **items;
102         size_t nr, alloc;
103 };
104 #define COMMIT_STACK_INIT { NULL, 0, 0 }
105
106 static void commit_stack_push(struct commit_stack *stack, struct commit *commit)
107 {
108         ALLOC_GROW(stack->items, stack->nr + 1, stack->alloc);
109         stack->items[stack->nr++] = commit;
110 }
111
112 static struct commit *commit_stack_pop(struct commit_stack *stack)
113 {
114         return stack->nr ? stack->items[--stack->nr] : NULL;
115 }
116
117 static void commit_stack_clear(struct commit_stack *stack)
118 {
119         FREE_AND_NULL(stack->items);
120         stack->nr = stack->alloc = 0;
121 }
122
123 static void mark_one_parent_uninteresting(struct commit *commit,
124                                           struct commit_stack *pending)
125 {
126         struct commit_list *l;
127
128         if (commit->object.flags & UNINTERESTING)
129                 return;
130         commit->object.flags |= UNINTERESTING;
131
132         /*
133          * Normally we haven't parsed the parent
134          * yet, so we won't have a parent of a parent
135          * here. However, it may turn out that we've
136          * reached this commit some other way (where it
137          * wasn't uninteresting), in which case we need
138          * to mark its parents recursively too..
139          */
140         for (l = commit->parents; l; l = l->next)
141                 commit_stack_push(pending, l->item);
142 }
143
144 void mark_parents_uninteresting(struct commit *commit)
145 {
146         struct commit_stack pending = COMMIT_STACK_INIT;
147         struct commit_list *l;
148
149         for (l = commit->parents; l; l = l->next)
150                 mark_one_parent_uninteresting(l->item, &pending);
151
152         while (pending.nr > 0)
153                 mark_one_parent_uninteresting(commit_stack_pop(&pending),
154                                               &pending);
155
156         commit_stack_clear(&pending);
157 }
158
159 static void add_pending_object_with_path(struct rev_info *revs,
160                                          struct object *obj,
161                                          const char *name, unsigned mode,
162                                          const char *path)
163 {
164         if (!obj)
165                 return;
166         if (revs->no_walk && (obj->flags & UNINTERESTING))
167                 revs->no_walk = 0;
168         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
169                 struct strbuf buf = STRBUF_INIT;
170                 int len = interpret_branch_name(name, 0, &buf, 0);
171
172                 if (0 < len && name[len] && buf.len)
173                         strbuf_addstr(&buf, name + len);
174                 add_reflog_for_walk(revs->reflog_info,
175                                     (struct commit *)obj,
176                                     buf.buf[0] ? buf.buf: name);
177                 strbuf_release(&buf);
178                 return; /* do not add the commit itself */
179         }
180         obj->flags |= USER_GIVEN;
181         add_object_array_with_path(obj, name, &revs->pending, mode, path);
182 }
183
184 static void add_pending_object_with_mode(struct rev_info *revs,
185                                          struct object *obj,
186                                          const char *name, unsigned mode)
187 {
188         add_pending_object_with_path(revs, obj, name, mode, NULL);
189 }
190
191 void add_pending_object(struct rev_info *revs,
192                         struct object *obj, const char *name)
193 {
194         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
195 }
196
197 void add_head_to_pending(struct rev_info *revs)
198 {
199         struct object_id oid;
200         struct object *obj;
201         if (get_oid("HEAD", &oid))
202                 return;
203         obj = parse_object(revs->repo, &oid);
204         if (!obj)
205                 return;
206         add_pending_object(revs, obj, "HEAD");
207 }
208
209 static struct object *get_reference(struct rev_info *revs, const char *name,
210                                     const struct object_id *oid,
211                                     unsigned int flags)
212 {
213         struct object *object;
214
215         object = parse_object(revs->repo, oid);
216         if (!object) {
217                 if (revs->ignore_missing)
218                         return object;
219                 if (revs->exclude_promisor_objects && is_promisor_object(oid))
220                         return NULL;
221                 die("bad object %s", name);
222         }
223         object->flags |= flags;
224         return object;
225 }
226
227 void add_pending_oid(struct rev_info *revs, const char *name,
228                       const struct object_id *oid, unsigned int flags)
229 {
230         struct object *object = get_reference(revs, name, oid, flags);
231         add_pending_object(revs, object, name);
232 }
233
234 static struct commit *handle_commit(struct rev_info *revs,
235                                     struct object_array_entry *entry)
236 {
237         struct object *object = entry->item;
238         const char *name = entry->name;
239         const char *path = entry->path;
240         unsigned int mode = entry->mode;
241         unsigned long flags = object->flags;
242
243         /*
244          * Tag object? Look what it points to..
245          */
246         while (object->type == OBJ_TAG) {
247                 struct tag *tag = (struct tag *) object;
248                 if (revs->tag_objects && !(flags & UNINTERESTING))
249                         add_pending_object(revs, object, tag->tag);
250                 if (!tag->tagged)
251                         die("bad tag");
252                 object = parse_object(revs->repo, &tag->tagged->oid);
253                 if (!object) {
254                         if (revs->ignore_missing_links || (flags & UNINTERESTING))
255                                 return NULL;
256                         if (revs->exclude_promisor_objects &&
257                             is_promisor_object(&tag->tagged->oid))
258                                 return NULL;
259                         die("bad object %s", oid_to_hex(&tag->tagged->oid));
260                 }
261                 object->flags |= flags;
262                 /*
263                  * We'll handle the tagged object by looping or dropping
264                  * through to the non-tag handlers below. Do not
265                  * propagate path data from the tag's pending entry.
266                  */
267                 path = NULL;
268                 mode = 0;
269         }
270
271         /*
272          * Commit object? Just return it, we'll do all the complex
273          * reachability crud.
274          */
275         if (object->type == OBJ_COMMIT) {
276                 struct commit *commit = (struct commit *)object;
277
278                 if (parse_commit(commit) < 0)
279                         die("unable to parse commit %s", name);
280                 if (flags & UNINTERESTING) {
281                         mark_parents_uninteresting(commit);
282                         revs->limited = 1;
283                 }
284                 if (revs->sources) {
285                         char **slot = revision_sources_at(revs->sources, commit);
286
287                         if (!*slot)
288                                 *slot = xstrdup(name);
289                 }
290                 return commit;
291         }
292
293         /*
294          * Tree object? Either mark it uninteresting, or add it
295          * to the list of objects to look at later..
296          */
297         if (object->type == OBJ_TREE) {
298                 struct tree *tree = (struct tree *)object;
299                 if (!revs->tree_objects)
300                         return NULL;
301                 if (flags & UNINTERESTING) {
302                         mark_tree_contents_uninteresting(revs->repo, tree);
303                         return NULL;
304                 }
305                 add_pending_object_with_path(revs, object, name, mode, path);
306                 return NULL;
307         }
308
309         /*
310          * Blob object? You know the drill by now..
311          */
312         if (object->type == OBJ_BLOB) {
313                 if (!revs->blob_objects)
314                         return NULL;
315                 if (flags & UNINTERESTING)
316                         return NULL;
317                 add_pending_object_with_path(revs, object, name, mode, path);
318                 return NULL;
319         }
320         die("%s is unknown object", name);
321 }
322
323 static int everybody_uninteresting(struct commit_list *orig,
324                                    struct commit **interesting_cache)
325 {
326         struct commit_list *list = orig;
327
328         if (*interesting_cache) {
329                 struct commit *commit = *interesting_cache;
330                 if (!(commit->object.flags & UNINTERESTING))
331                         return 0;
332         }
333
334         while (list) {
335                 struct commit *commit = list->item;
336                 list = list->next;
337                 if (commit->object.flags & UNINTERESTING)
338                         continue;
339
340                 *interesting_cache = commit;
341                 return 0;
342         }
343         return 1;
344 }
345
346 /*
347  * A definition of "relevant" commit that we can use to simplify limited graphs
348  * by eliminating side branches.
349  *
350  * A "relevant" commit is one that is !UNINTERESTING (ie we are including it
351  * in our list), or that is a specified BOTTOM commit. Then after computing
352  * a limited list, during processing we can generally ignore boundary merges
353  * coming from outside the graph, (ie from irrelevant parents), and treat
354  * those merges as if they were single-parent. TREESAME is defined to consider
355  * only relevant parents, if any. If we are TREESAME to our on-graph parents,
356  * we don't care if we were !TREESAME to non-graph parents.
357  *
358  * Treating bottom commits as relevant ensures that a limited graph's
359  * connection to the actual bottom commit is not viewed as a side branch, but
360  * treated as part of the graph. For example:
361  *
362  *   ....Z...A---X---o---o---B
363  *        .     /
364  *         W---Y
365  *
366  * When computing "A..B", the A-X connection is at least as important as
367  * Y-X, despite A being flagged UNINTERESTING.
368  *
369  * And when computing --ancestry-path "A..B", the A-X connection is more
370  * important than Y-X, despite both A and Y being flagged UNINTERESTING.
371  */
372 static inline int relevant_commit(struct commit *commit)
373 {
374         return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
375 }
376
377 /*
378  * Return a single relevant commit from a parent list. If we are a TREESAME
379  * commit, and this selects one of our parents, then we can safely simplify to
380  * that parent.
381  */
382 static struct commit *one_relevant_parent(const struct rev_info *revs,
383                                           struct commit_list *orig)
384 {
385         struct commit_list *list = orig;
386         struct commit *relevant = NULL;
387
388         if (!orig)
389                 return NULL;
390
391         /*
392          * For 1-parent commits, or if first-parent-only, then return that
393          * first parent (even if not "relevant" by the above definition).
394          * TREESAME will have been set purely on that parent.
395          */
396         if (revs->first_parent_only || !orig->next)
397                 return orig->item;
398
399         /*
400          * For multi-parent commits, identify a sole relevant parent, if any.
401          * If we have only one relevant parent, then TREESAME will be set purely
402          * with regard to that parent, and we can simplify accordingly.
403          *
404          * If we have more than one relevant parent, or no relevant parents
405          * (and multiple irrelevant ones), then we can't select a parent here
406          * and return NULL.
407          */
408         while (list) {
409                 struct commit *commit = list->item;
410                 list = list->next;
411                 if (relevant_commit(commit)) {
412                         if (relevant)
413                                 return NULL;
414                         relevant = commit;
415                 }
416         }
417         return relevant;
418 }
419
420 /*
421  * The goal is to get REV_TREE_NEW as the result only if the
422  * diff consists of all '+' (and no other changes), REV_TREE_OLD
423  * if the whole diff is removal of old data, and otherwise
424  * REV_TREE_DIFFERENT (of course if the trees are the same we
425  * want REV_TREE_SAME).
426  *
427  * The only time we care about the distinction is when
428  * remove_empty_trees is in effect, in which case we care only about
429  * whether the whole change is REV_TREE_NEW, or if there's another type
430  * of change. Which means we can stop the diff early in either of these
431  * cases:
432  *
433  *   1. We're not using remove_empty_trees at all.
434  *
435  *   2. We saw anything except REV_TREE_NEW.
436  */
437 static int tree_difference = REV_TREE_SAME;
438
439 static void file_add_remove(struct diff_options *options,
440                     int addremove, unsigned mode,
441                     const struct object_id *oid,
442                     int oid_valid,
443                     const char *fullpath, unsigned dirty_submodule)
444 {
445         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
446         struct rev_info *revs = options->change_fn_data;
447
448         tree_difference |= diff;
449         if (!revs->remove_empty_trees || tree_difference != REV_TREE_NEW)
450                 options->flags.has_changes = 1;
451 }
452
453 static void file_change(struct diff_options *options,
454                  unsigned old_mode, unsigned new_mode,
455                  const struct object_id *old_oid,
456                  const struct object_id *new_oid,
457                  int old_oid_valid, int new_oid_valid,
458                  const char *fullpath,
459                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
460 {
461         tree_difference = REV_TREE_DIFFERENT;
462         options->flags.has_changes = 1;
463 }
464
465 static int rev_compare_tree(struct rev_info *revs,
466                             struct commit *parent, struct commit *commit)
467 {
468         struct tree *t1 = get_commit_tree(parent);
469         struct tree *t2 = get_commit_tree(commit);
470
471         if (!t1)
472                 return REV_TREE_NEW;
473         if (!t2)
474                 return REV_TREE_OLD;
475
476         if (revs->simplify_by_decoration) {
477                 /*
478                  * If we are simplifying by decoration, then the commit
479                  * is worth showing if it has a tag pointing at it.
480                  */
481                 if (get_name_decoration(&commit->object))
482                         return REV_TREE_DIFFERENT;
483                 /*
484                  * A commit that is not pointed by a tag is uninteresting
485                  * if we are not limited by path.  This means that you will
486                  * see the usual "commits that touch the paths" plus any
487                  * tagged commit by specifying both --simplify-by-decoration
488                  * and pathspec.
489                  */
490                 if (!revs->prune_data.nr)
491                         return REV_TREE_SAME;
492         }
493
494         tree_difference = REV_TREE_SAME;
495         revs->pruning.flags.has_changes = 0;
496         if (diff_tree_oid(&t1->object.oid, &t2->object.oid, "",
497                            &revs->pruning) < 0)
498                 return REV_TREE_DIFFERENT;
499         return tree_difference;
500 }
501
502 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
503 {
504         int retval;
505         struct tree *t1 = get_commit_tree(commit);
506
507         if (!t1)
508                 return 0;
509
510         tree_difference = REV_TREE_SAME;
511         revs->pruning.flags.has_changes = 0;
512         retval = diff_tree_oid(NULL, &t1->object.oid, "", &revs->pruning);
513
514         return retval >= 0 && (tree_difference == REV_TREE_SAME);
515 }
516
517 struct treesame_state {
518         unsigned int nparents;
519         unsigned char treesame[FLEX_ARRAY];
520 };
521
522 static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
523 {
524         unsigned n = commit_list_count(commit->parents);
525         struct treesame_state *st = xcalloc(1, st_add(sizeof(*st), n));
526         st->nparents = n;
527         add_decoration(&revs->treesame, &commit->object, st);
528         return st;
529 }
530
531 /*
532  * Must be called immediately after removing the nth_parent from a commit's
533  * parent list, if we are maintaining the per-parent treesame[] decoration.
534  * This does not recalculate the master TREESAME flag - update_treesame()
535  * should be called to update it after a sequence of treesame[] modifications
536  * that may have affected it.
537  */
538 static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
539 {
540         struct treesame_state *st;
541         int old_same;
542
543         if (!commit->parents) {
544                 /*
545                  * Have just removed the only parent from a non-merge.
546                  * Different handling, as we lack decoration.
547                  */
548                 if (nth_parent != 0)
549                         die("compact_treesame %u", nth_parent);
550                 old_same = !!(commit->object.flags & TREESAME);
551                 if (rev_same_tree_as_empty(revs, commit))
552                         commit->object.flags |= TREESAME;
553                 else
554                         commit->object.flags &= ~TREESAME;
555                 return old_same;
556         }
557
558         st = lookup_decoration(&revs->treesame, &commit->object);
559         if (!st || nth_parent >= st->nparents)
560                 die("compact_treesame %u", nth_parent);
561
562         old_same = st->treesame[nth_parent];
563         memmove(st->treesame + nth_parent,
564                 st->treesame + nth_parent + 1,
565                 st->nparents - nth_parent - 1);
566
567         /*
568          * If we've just become a non-merge commit, update TREESAME
569          * immediately, and remove the no-longer-needed decoration.
570          * If still a merge, defer update until update_treesame().
571          */
572         if (--st->nparents == 1) {
573                 if (commit->parents->next)
574                         die("compact_treesame parents mismatch");
575                 if (st->treesame[0] && revs->dense)
576                         commit->object.flags |= TREESAME;
577                 else
578                         commit->object.flags &= ~TREESAME;
579                 free(add_decoration(&revs->treesame, &commit->object, NULL));
580         }
581
582         return old_same;
583 }
584
585 static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
586 {
587         if (commit->parents && commit->parents->next) {
588                 unsigned n;
589                 struct treesame_state *st;
590                 struct commit_list *p;
591                 unsigned relevant_parents;
592                 unsigned relevant_change, irrelevant_change;
593
594                 st = lookup_decoration(&revs->treesame, &commit->object);
595                 if (!st)
596                         die("update_treesame %s", oid_to_hex(&commit->object.oid));
597                 relevant_parents = 0;
598                 relevant_change = irrelevant_change = 0;
599                 for (p = commit->parents, n = 0; p; n++, p = p->next) {
600                         if (relevant_commit(p->item)) {
601                                 relevant_change |= !st->treesame[n];
602                                 relevant_parents++;
603                         } else
604                                 irrelevant_change |= !st->treesame[n];
605                 }
606                 if (relevant_parents ? relevant_change : irrelevant_change)
607                         commit->object.flags &= ~TREESAME;
608                 else
609                         commit->object.flags |= TREESAME;
610         }
611
612         return commit->object.flags & TREESAME;
613 }
614
615 static inline int limiting_can_increase_treesame(const struct rev_info *revs)
616 {
617         /*
618          * TREESAME is irrelevant unless prune && dense;
619          * if simplify_history is set, we can't have a mixture of TREESAME and
620          *    !TREESAME INTERESTING parents (and we don't have treesame[]
621          *    decoration anyway);
622          * if first_parent_only is set, then the TREESAME flag is locked
623          *    against the first parent (and again we lack treesame[] decoration).
624          */
625         return revs->prune && revs->dense &&
626                !revs->simplify_history &&
627                !revs->first_parent_only;
628 }
629
630 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
631 {
632         struct commit_list **pp, *parent;
633         struct treesame_state *ts = NULL;
634         int relevant_change = 0, irrelevant_change = 0;
635         int relevant_parents, nth_parent;
636
637         /*
638          * If we don't do pruning, everything is interesting
639          */
640         if (!revs->prune)
641                 return;
642
643         if (!get_commit_tree(commit))
644                 return;
645
646         if (!commit->parents) {
647                 if (rev_same_tree_as_empty(revs, commit))
648                         commit->object.flags |= TREESAME;
649                 return;
650         }
651
652         /*
653          * Normal non-merge commit? If we don't want to make the
654          * history dense, we consider it always to be a change..
655          */
656         if (!revs->dense && !commit->parents->next)
657                 return;
658
659         for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
660              (parent = *pp) != NULL;
661              pp = &parent->next, nth_parent++) {
662                 struct commit *p = parent->item;
663                 if (relevant_commit(p))
664                         relevant_parents++;
665
666                 if (nth_parent == 1) {
667                         /*
668                          * This our second loop iteration - so we now know
669                          * we're dealing with a merge.
670                          *
671                          * Do not compare with later parents when we care only about
672                          * the first parent chain, in order to avoid derailing the
673                          * traversal to follow a side branch that brought everything
674                          * in the path we are limited to by the pathspec.
675                          */
676                         if (revs->first_parent_only)
677                                 break;
678                         /*
679                          * If this will remain a potentially-simplifiable
680                          * merge, remember per-parent treesame if needed.
681                          * Initialise the array with the comparison from our
682                          * first iteration.
683                          */
684                         if (revs->treesame.name &&
685                             !revs->simplify_history &&
686                             !(commit->object.flags & UNINTERESTING)) {
687                                 ts = initialise_treesame(revs, commit);
688                                 if (!(irrelevant_change || relevant_change))
689                                         ts->treesame[0] = 1;
690                         }
691                 }
692                 if (parse_commit(p) < 0)
693                         die("cannot simplify commit %s (because of %s)",
694                             oid_to_hex(&commit->object.oid),
695                             oid_to_hex(&p->object.oid));
696                 switch (rev_compare_tree(revs, p, commit)) {
697                 case REV_TREE_SAME:
698                         if (!revs->simplify_history || !relevant_commit(p)) {
699                                 /* Even if a merge with an uninteresting
700                                  * side branch brought the entire change
701                                  * we are interested in, we do not want
702                                  * to lose the other branches of this
703                                  * merge, so we just keep going.
704                                  */
705                                 if (ts)
706                                         ts->treesame[nth_parent] = 1;
707                                 continue;
708                         }
709                         parent->next = NULL;
710                         commit->parents = parent;
711                         commit->object.flags |= TREESAME;
712                         return;
713
714                 case REV_TREE_NEW:
715                         if (revs->remove_empty_trees &&
716                             rev_same_tree_as_empty(revs, p)) {
717                                 /* We are adding all the specified
718                                  * paths from this parent, so the
719                                  * history beyond this parent is not
720                                  * interesting.  Remove its parents
721                                  * (they are grandparents for us).
722                                  * IOW, we pretend this parent is a
723                                  * "root" commit.
724                                  */
725                                 if (parse_commit(p) < 0)
726                                         die("cannot simplify commit %s (invalid %s)",
727                                             oid_to_hex(&commit->object.oid),
728                                             oid_to_hex(&p->object.oid));
729                                 p->parents = NULL;
730                         }
731                 /* fallthrough */
732                 case REV_TREE_OLD:
733                 case REV_TREE_DIFFERENT:
734                         if (relevant_commit(p))
735                                 relevant_change = 1;
736                         else
737                                 irrelevant_change = 1;
738                         continue;
739                 }
740                 die("bad tree compare for commit %s", oid_to_hex(&commit->object.oid));
741         }
742
743         /*
744          * TREESAME is straightforward for single-parent commits. For merge
745          * commits, it is most useful to define it so that "irrelevant"
746          * parents cannot make us !TREESAME - if we have any relevant
747          * parents, then we only consider TREESAMEness with respect to them,
748          * allowing irrelevant merges from uninteresting branches to be
749          * simplified away. Only if we have only irrelevant parents do we
750          * base TREESAME on them. Note that this logic is replicated in
751          * update_treesame, which should be kept in sync.
752          */
753         if (relevant_parents ? !relevant_change : !irrelevant_change)
754                 commit->object.flags |= TREESAME;
755 }
756
757 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
758                     struct commit_list *cached_base, struct commit_list **cache)
759 {
760         struct commit_list *new_entry;
761
762         if (cached_base && p->date < cached_base->item->date)
763                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
764         else
765                 new_entry = commit_list_insert_by_date(p, head);
766
767         if (cache && (!*cache || p->date < (*cache)->item->date))
768                 *cache = new_entry;
769 }
770
771 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
772                     struct commit_list **list, struct commit_list **cache_ptr)
773 {
774         struct commit_list *parent = commit->parents;
775         unsigned left_flag;
776         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
777
778         if (commit->object.flags & ADDED)
779                 return 0;
780         commit->object.flags |= ADDED;
781
782         if (revs->include_check &&
783             !revs->include_check(commit, revs->include_check_data))
784                 return 0;
785
786         /*
787          * If the commit is uninteresting, don't try to
788          * prune parents - we want the maximal uninteresting
789          * set.
790          *
791          * Normally we haven't parsed the parent
792          * yet, so we won't have a parent of a parent
793          * here. However, it may turn out that we've
794          * reached this commit some other way (where it
795          * wasn't uninteresting), in which case we need
796          * to mark its parents recursively too..
797          */
798         if (commit->object.flags & UNINTERESTING) {
799                 while (parent) {
800                         struct commit *p = parent->item;
801                         parent = parent->next;
802                         if (p)
803                                 p->object.flags |= UNINTERESTING;
804                         if (parse_commit_gently(p, 1) < 0)
805                                 continue;
806                         if (p->parents)
807                                 mark_parents_uninteresting(p);
808                         if (p->object.flags & SEEN)
809                                 continue;
810                         p->object.flags |= SEEN;
811                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
812                 }
813                 return 0;
814         }
815
816         /*
817          * Ok, the commit wasn't uninteresting. Try to
818          * simplify the commit history and find the parent
819          * that has no differences in the path set if one exists.
820          */
821         try_to_simplify_commit(revs, commit);
822
823         if (revs->no_walk)
824                 return 0;
825
826         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
827
828         for (parent = commit->parents; parent; parent = parent->next) {
829                 struct commit *p = parent->item;
830                 int gently = revs->ignore_missing_links ||
831                              revs->exclude_promisor_objects;
832                 if (parse_commit_gently(p, gently) < 0) {
833                         if (revs->exclude_promisor_objects &&
834                             is_promisor_object(&p->object.oid)) {
835                                 if (revs->first_parent_only)
836                                         break;
837                                 continue;
838                         }
839                         return -1;
840                 }
841                 if (revs->sources) {
842                         char **slot = revision_sources_at(revs->sources, p);
843
844                         if (!*slot)
845                                 *slot = *revision_sources_at(revs->sources, commit);
846                 }
847                 p->object.flags |= left_flag;
848                 if (!(p->object.flags & SEEN)) {
849                         p->object.flags |= SEEN;
850                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
851                 }
852                 if (revs->first_parent_only)
853                         break;
854         }
855         return 0;
856 }
857
858 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
859 {
860         struct commit_list *p;
861         int left_count = 0, right_count = 0;
862         int left_first;
863         struct patch_ids ids;
864         unsigned cherry_flag;
865
866         /* First count the commits on the left and on the right */
867         for (p = list; p; p = p->next) {
868                 struct commit *commit = p->item;
869                 unsigned flags = commit->object.flags;
870                 if (flags & BOUNDARY)
871                         ;
872                 else if (flags & SYMMETRIC_LEFT)
873                         left_count++;
874                 else
875                         right_count++;
876         }
877
878         if (!left_count || !right_count)
879                 return;
880
881         left_first = left_count < right_count;
882         init_patch_ids(revs->repo, &ids);
883         ids.diffopts.pathspec = revs->diffopt.pathspec;
884
885         /* Compute patch-ids for one side */
886         for (p = list; p; p = p->next) {
887                 struct commit *commit = p->item;
888                 unsigned flags = commit->object.flags;
889
890                 if (flags & BOUNDARY)
891                         continue;
892                 /*
893                  * If we have fewer left, left_first is set and we omit
894                  * commits on the right branch in this loop.  If we have
895                  * fewer right, we skip the left ones.
896                  */
897                 if (left_first != !!(flags & SYMMETRIC_LEFT))
898                         continue;
899                 add_commit_patch_id(commit, &ids);
900         }
901
902         /* either cherry_mark or cherry_pick are true */
903         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
904
905         /* Check the other side */
906         for (p = list; p; p = p->next) {
907                 struct commit *commit = p->item;
908                 struct patch_id *id;
909                 unsigned flags = commit->object.flags;
910
911                 if (flags & BOUNDARY)
912                         continue;
913                 /*
914                  * If we have fewer left, left_first is set and we omit
915                  * commits on the left branch in this loop.
916                  */
917                 if (left_first == !!(flags & SYMMETRIC_LEFT))
918                         continue;
919
920                 /*
921                  * Have we seen the same patch id?
922                  */
923                 id = has_commit_patch_id(commit, &ids);
924                 if (!id)
925                         continue;
926
927                 commit->object.flags |= cherry_flag;
928                 id->commit->object.flags |= cherry_flag;
929         }
930
931         free_patch_ids(&ids);
932 }
933
934 /* How many extra uninteresting commits we want to see.. */
935 #define SLOP 5
936
937 static int still_interesting(struct commit_list *src, timestamp_t date, int slop,
938                              struct commit **interesting_cache)
939 {
940         /*
941          * No source list at all? We're definitely done..
942          */
943         if (!src)
944                 return 0;
945
946         /*
947          * Does the destination list contain entries with a date
948          * before the source list? Definitely _not_ done.
949          */
950         if (date <= src->item->date)
951                 return SLOP;
952
953         /*
954          * Does the source list still have interesting commits in
955          * it? Definitely not done..
956          */
957         if (!everybody_uninteresting(src, interesting_cache))
958                 return SLOP;
959
960         /* Ok, we're closing in.. */
961         return slop-1;
962 }
963
964 /*
965  * "rev-list --ancestry-path A..B" computes commits that are ancestors
966  * of B but not ancestors of A but further limits the result to those
967  * that are descendants of A.  This takes the list of bottom commits and
968  * the result of "A..B" without --ancestry-path, and limits the latter
969  * further to the ones that can reach one of the commits in "bottom".
970  */
971 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
972 {
973         struct commit_list *p;
974         struct commit_list *rlist = NULL;
975         int made_progress;
976
977         /*
978          * Reverse the list so that it will be likely that we would
979          * process parents before children.
980          */
981         for (p = list; p; p = p->next)
982                 commit_list_insert(p->item, &rlist);
983
984         for (p = bottom; p; p = p->next)
985                 p->item->object.flags |= TMP_MARK;
986
987         /*
988          * Mark the ones that can reach bottom commits in "list",
989          * in a bottom-up fashion.
990          */
991         do {
992                 made_progress = 0;
993                 for (p = rlist; p; p = p->next) {
994                         struct commit *c = p->item;
995                         struct commit_list *parents;
996                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
997                                 continue;
998                         for (parents = c->parents;
999                              parents;
1000                              parents = parents->next) {
1001                                 if (!(parents->item->object.flags & TMP_MARK))
1002                                         continue;
1003                                 c->object.flags |= TMP_MARK;
1004                                 made_progress = 1;
1005                                 break;
1006                         }
1007                 }
1008         } while (made_progress);
1009
1010         /*
1011          * NEEDSWORK: decide if we want to remove parents that are
1012          * not marked with TMP_MARK from commit->parents for commits
1013          * in the resulting list.  We may not want to do that, though.
1014          */
1015
1016         /*
1017          * The ones that are not marked with TMP_MARK are uninteresting
1018          */
1019         for (p = list; p; p = p->next) {
1020                 struct commit *c = p->item;
1021                 if (c->object.flags & TMP_MARK)
1022                         continue;
1023                 c->object.flags |= UNINTERESTING;
1024         }
1025
1026         /* We are done with the TMP_MARK */
1027         for (p = list; p; p = p->next)
1028                 p->item->object.flags &= ~TMP_MARK;
1029         for (p = bottom; p; p = p->next)
1030                 p->item->object.flags &= ~TMP_MARK;
1031         free_commit_list(rlist);
1032 }
1033
1034 /*
1035  * Before walking the history, keep the set of "negative" refs the
1036  * caller has asked to exclude.
1037  *
1038  * This is used to compute "rev-list --ancestry-path A..B", as we need
1039  * to filter the result of "A..B" further to the ones that can actually
1040  * reach A.
1041  */
1042 static struct commit_list *collect_bottom_commits(struct commit_list *list)
1043 {
1044         struct commit_list *elem, *bottom = NULL;
1045         for (elem = list; elem; elem = elem->next)
1046                 if (elem->item->object.flags & BOTTOM)
1047                         commit_list_insert(elem->item, &bottom);
1048         return bottom;
1049 }
1050
1051 /* Assumes either left_only or right_only is set */
1052 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
1053 {
1054         struct commit_list *p;
1055
1056         for (p = list; p; p = p->next) {
1057                 struct commit *commit = p->item;
1058
1059                 if (revs->right_only) {
1060                         if (commit->object.flags & SYMMETRIC_LEFT)
1061                                 commit->object.flags |= SHOWN;
1062                 } else  /* revs->left_only is set */
1063                         if (!(commit->object.flags & SYMMETRIC_LEFT))
1064                                 commit->object.flags |= SHOWN;
1065         }
1066 }
1067
1068 static int limit_list(struct rev_info *revs)
1069 {
1070         int slop = SLOP;
1071         timestamp_t date = TIME_MAX;
1072         struct commit_list *list = revs->commits;
1073         struct commit_list *newlist = NULL;
1074         struct commit_list **p = &newlist;
1075         struct commit_list *bottom = NULL;
1076         struct commit *interesting_cache = NULL;
1077
1078         if (revs->ancestry_path) {
1079                 bottom = collect_bottom_commits(list);
1080                 if (!bottom)
1081                         die("--ancestry-path given but there are no bottom commits");
1082         }
1083
1084         while (list) {
1085                 struct commit *commit = pop_commit(&list);
1086                 struct object *obj = &commit->object;
1087                 show_early_output_fn_t show;
1088
1089                 if (commit == interesting_cache)
1090                         interesting_cache = NULL;
1091
1092                 if (revs->max_age != -1 && (commit->date < revs->max_age))
1093                         obj->flags |= UNINTERESTING;
1094                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
1095                         return -1;
1096                 if (obj->flags & UNINTERESTING) {
1097                         mark_parents_uninteresting(commit);
1098                         slop = still_interesting(list, date, slop, &interesting_cache);
1099                         if (slop)
1100                                 continue;
1101                         break;
1102                 }
1103                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1104                         continue;
1105                 date = commit->date;
1106                 p = &commit_list_insert(commit, p)->next;
1107
1108                 show = show_early_output;
1109                 if (!show)
1110                         continue;
1111
1112                 show(revs, newlist);
1113                 show_early_output = NULL;
1114         }
1115         if (revs->cherry_pick || revs->cherry_mark)
1116                 cherry_pick_list(newlist, revs);
1117
1118         if (revs->left_only || revs->right_only)
1119                 limit_left_right(newlist, revs);
1120
1121         if (bottom) {
1122                 limit_to_ancestry(bottom, newlist);
1123                 free_commit_list(bottom);
1124         }
1125
1126         /*
1127          * Check if any commits have become TREESAME by some of their parents
1128          * becoming UNINTERESTING.
1129          */
1130         if (limiting_can_increase_treesame(revs))
1131                 for (list = newlist; list; list = list->next) {
1132                         struct commit *c = list->item;
1133                         if (c->object.flags & (UNINTERESTING | TREESAME))
1134                                 continue;
1135                         update_treesame(revs, c);
1136                 }
1137
1138         revs->commits = newlist;
1139         return 0;
1140 }
1141
1142 /*
1143  * Add an entry to refs->cmdline with the specified information.
1144  * *name is copied.
1145  */
1146 static void add_rev_cmdline(struct rev_info *revs,
1147                             struct object *item,
1148                             const char *name,
1149                             int whence,
1150                             unsigned flags)
1151 {
1152         struct rev_cmdline_info *info = &revs->cmdline;
1153         unsigned int nr = info->nr;
1154
1155         ALLOC_GROW(info->rev, nr + 1, info->alloc);
1156         info->rev[nr].item = item;
1157         info->rev[nr].name = xstrdup(name);
1158         info->rev[nr].whence = whence;
1159         info->rev[nr].flags = flags;
1160         info->nr++;
1161 }
1162
1163 static void add_rev_cmdline_list(struct rev_info *revs,
1164                                  struct commit_list *commit_list,
1165                                  int whence,
1166                                  unsigned flags)
1167 {
1168         while (commit_list) {
1169                 struct object *object = &commit_list->item->object;
1170                 add_rev_cmdline(revs, object, oid_to_hex(&object->oid),
1171                                 whence, flags);
1172                 commit_list = commit_list->next;
1173         }
1174 }
1175
1176 struct all_refs_cb {
1177         int all_flags;
1178         int warned_bad_reflog;
1179         struct rev_info *all_revs;
1180         const char *name_for_errormsg;
1181         struct ref_store *refs;
1182 };
1183
1184 int ref_excluded(struct string_list *ref_excludes, const char *path)
1185 {
1186         struct string_list_item *item;
1187
1188         if (!ref_excludes)
1189                 return 0;
1190         for_each_string_list_item(item, ref_excludes) {
1191                 if (!wildmatch(item->string, path, 0))
1192                         return 1;
1193         }
1194         return 0;
1195 }
1196
1197 static int handle_one_ref(const char *path, const struct object_id *oid,
1198                           int flag, void *cb_data)
1199 {
1200         struct all_refs_cb *cb = cb_data;
1201         struct object *object;
1202
1203         if (ref_excluded(cb->all_revs->ref_excludes, path))
1204             return 0;
1205
1206         object = get_reference(cb->all_revs, path, oid, cb->all_flags);
1207         add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
1208         add_pending_oid(cb->all_revs, path, oid, cb->all_flags);
1209         return 0;
1210 }
1211
1212 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
1213         unsigned flags)
1214 {
1215         cb->all_revs = revs;
1216         cb->all_flags = flags;
1217         revs->rev_input_given = 1;
1218         cb->refs = NULL;
1219 }
1220
1221 void clear_ref_exclusion(struct string_list **ref_excludes_p)
1222 {
1223         if (*ref_excludes_p) {
1224                 string_list_clear(*ref_excludes_p, 0);
1225                 free(*ref_excludes_p);
1226         }
1227         *ref_excludes_p = NULL;
1228 }
1229
1230 void add_ref_exclusion(struct string_list **ref_excludes_p, const char *exclude)
1231 {
1232         if (!*ref_excludes_p) {
1233                 *ref_excludes_p = xcalloc(1, sizeof(**ref_excludes_p));
1234                 (*ref_excludes_p)->strdup_strings = 1;
1235         }
1236         string_list_append(*ref_excludes_p, exclude);
1237 }
1238
1239 static void handle_refs(struct ref_store *refs,
1240                         struct rev_info *revs, unsigned flags,
1241                         int (*for_each)(struct ref_store *, each_ref_fn, void *))
1242 {
1243         struct all_refs_cb cb;
1244
1245         if (!refs) {
1246                 /* this could happen with uninitialized submodules */
1247                 return;
1248         }
1249
1250         init_all_refs_cb(&cb, revs, flags);
1251         for_each(refs, handle_one_ref, &cb);
1252 }
1253
1254 static void handle_one_reflog_commit(struct object_id *oid, void *cb_data)
1255 {
1256         struct all_refs_cb *cb = cb_data;
1257         if (!is_null_oid(oid)) {
1258                 struct object *o = parse_object(cb->all_revs->repo, oid);
1259                 if (o) {
1260                         o->flags |= cb->all_flags;
1261                         /* ??? CMDLINEFLAGS ??? */
1262                         add_pending_object(cb->all_revs, o, "");
1263                 }
1264                 else if (!cb->warned_bad_reflog) {
1265                         warning("reflog of '%s' references pruned commits",
1266                                 cb->name_for_errormsg);
1267                         cb->warned_bad_reflog = 1;
1268                 }
1269         }
1270 }
1271
1272 static int handle_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
1273                 const char *email, timestamp_t timestamp, int tz,
1274                 const char *message, void *cb_data)
1275 {
1276         handle_one_reflog_commit(ooid, cb_data);
1277         handle_one_reflog_commit(noid, cb_data);
1278         return 0;
1279 }
1280
1281 static int handle_one_reflog(const char *path, const struct object_id *oid,
1282                              int flag, void *cb_data)
1283 {
1284         struct all_refs_cb *cb = cb_data;
1285         cb->warned_bad_reflog = 0;
1286         cb->name_for_errormsg = path;
1287         refs_for_each_reflog_ent(cb->refs, path,
1288                                  handle_one_reflog_ent, cb_data);
1289         return 0;
1290 }
1291
1292 static void add_other_reflogs_to_pending(struct all_refs_cb *cb)
1293 {
1294         struct worktree **worktrees, **p;
1295
1296         worktrees = get_worktrees(0);
1297         for (p = worktrees; *p; p++) {
1298                 struct worktree *wt = *p;
1299
1300                 if (wt->is_current)
1301                         continue;
1302
1303                 cb->refs = get_worktree_ref_store(wt);
1304                 refs_for_each_reflog(cb->refs,
1305                                      handle_one_reflog,
1306                                      cb);
1307         }
1308         free_worktrees(worktrees);
1309 }
1310
1311 void add_reflogs_to_pending(struct rev_info *revs, unsigned flags)
1312 {
1313         struct all_refs_cb cb;
1314
1315         cb.all_revs = revs;
1316         cb.all_flags = flags;
1317         cb.refs = get_main_ref_store(revs->repo);
1318         for_each_reflog(handle_one_reflog, &cb);
1319
1320         if (!revs->single_worktree)
1321                 add_other_reflogs_to_pending(&cb);
1322 }
1323
1324 static void add_cache_tree(struct cache_tree *it, struct rev_info *revs,
1325                            struct strbuf *path)
1326 {
1327         size_t baselen = path->len;
1328         int i;
1329
1330         if (it->entry_count >= 0) {
1331                 struct tree *tree = lookup_tree(revs->repo, &it->oid);
1332                 add_pending_object_with_path(revs, &tree->object, "",
1333                                              040000, path->buf);
1334         }
1335
1336         for (i = 0; i < it->subtree_nr; i++) {
1337                 struct cache_tree_sub *sub = it->down[i];
1338                 strbuf_addf(path, "%s%s", baselen ? "/" : "", sub->name);
1339                 add_cache_tree(sub->cache_tree, revs, path);
1340                 strbuf_setlen(path, baselen);
1341         }
1342
1343 }
1344
1345 static void do_add_index_objects_to_pending(struct rev_info *revs,
1346                                             struct index_state *istate)
1347 {
1348         int i;
1349
1350         for (i = 0; i < istate->cache_nr; i++) {
1351                 struct cache_entry *ce = istate->cache[i];
1352                 struct blob *blob;
1353
1354                 if (S_ISGITLINK(ce->ce_mode))
1355                         continue;
1356
1357                 blob = lookup_blob(revs->repo, &ce->oid);
1358                 if (!blob)
1359                         die("unable to add index blob to traversal");
1360                 add_pending_object_with_path(revs, &blob->object, "",
1361                                              ce->ce_mode, ce->name);
1362         }
1363
1364         if (istate->cache_tree) {
1365                 struct strbuf path = STRBUF_INIT;
1366                 add_cache_tree(istate->cache_tree, revs, &path);
1367                 strbuf_release(&path);
1368         }
1369 }
1370
1371 void add_index_objects_to_pending(struct rev_info *revs, unsigned int flags)
1372 {
1373         struct worktree **worktrees, **p;
1374
1375         read_index(revs->repo->index);
1376         do_add_index_objects_to_pending(revs, revs->repo->index);
1377
1378         if (revs->single_worktree)
1379                 return;
1380
1381         worktrees = get_worktrees(0);
1382         for (p = worktrees; *p; p++) {
1383                 struct worktree *wt = *p;
1384                 struct index_state istate = { NULL };
1385
1386                 if (wt->is_current)
1387                         continue; /* current index already taken care of */
1388
1389                 if (read_index_from(&istate,
1390                                     worktree_git_path(wt, "index"),
1391                                     get_worktree_git_dir(wt)) > 0)
1392                         do_add_index_objects_to_pending(revs, &istate);
1393                 discard_index(&istate);
1394         }
1395         free_worktrees(worktrees);
1396 }
1397
1398 static int add_parents_only(struct rev_info *revs, const char *arg_, int flags,
1399                             int exclude_parent)
1400 {
1401         struct object_id oid;
1402         struct object *it;
1403         struct commit *commit;
1404         struct commit_list *parents;
1405         int parent_number;
1406         const char *arg = arg_;
1407
1408         if (*arg == '^') {
1409                 flags ^= UNINTERESTING | BOTTOM;
1410                 arg++;
1411         }
1412         if (get_oid_committish(arg, &oid))
1413                 return 0;
1414         while (1) {
1415                 it = get_reference(revs, arg, &oid, 0);
1416                 if (!it && revs->ignore_missing)
1417                         return 0;
1418                 if (it->type != OBJ_TAG)
1419                         break;
1420                 if (!((struct tag*)it)->tagged)
1421                         return 0;
1422                 oidcpy(&oid, &((struct tag*)it)->tagged->oid);
1423         }
1424         if (it->type != OBJ_COMMIT)
1425                 return 0;
1426         commit = (struct commit *)it;
1427         if (exclude_parent &&
1428             exclude_parent > commit_list_count(commit->parents))
1429                 return 0;
1430         for (parents = commit->parents, parent_number = 1;
1431              parents;
1432              parents = parents->next, parent_number++) {
1433                 if (exclude_parent && parent_number != exclude_parent)
1434                         continue;
1435
1436                 it = &parents->item->object;
1437                 it->flags |= flags;
1438                 add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
1439                 add_pending_object(revs, it, arg);
1440         }
1441         return 1;
1442 }
1443
1444 void repo_init_revisions(struct repository *r,
1445                          struct rev_info *revs,
1446                          const char *prefix)
1447 {
1448         memset(revs, 0, sizeof(*revs));
1449
1450         revs->repo = r;
1451         revs->abbrev = DEFAULT_ABBREV;
1452         revs->ignore_merges = 1;
1453         revs->simplify_history = 1;
1454         revs->pruning.flags.recursive = 1;
1455         revs->pruning.flags.quick = 1;
1456         revs->pruning.add_remove = file_add_remove;
1457         revs->pruning.change = file_change;
1458         revs->pruning.change_fn_data = revs;
1459         revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1460         revs->dense = 1;
1461         revs->prefix = prefix;
1462         revs->max_age = -1;
1463         revs->min_age = -1;
1464         revs->skip_count = -1;
1465         revs->max_count = -1;
1466         revs->max_parents = -1;
1467         revs->expand_tabs_in_log = -1;
1468
1469         revs->commit_format = CMIT_FMT_DEFAULT;
1470         revs->expand_tabs_in_log_default = 8;
1471
1472         init_grep_defaults(revs->repo);
1473         grep_init(&revs->grep_filter, revs->repo, prefix);
1474         revs->grep_filter.status_only = 1;
1475
1476         repo_diff_setup(revs->repo, &revs->diffopt);
1477         if (prefix && !revs->diffopt.prefix) {
1478                 revs->diffopt.prefix = prefix;
1479                 revs->diffopt.prefix_length = strlen(prefix);
1480         }
1481
1482         revs->notes_opt.use_default_notes = -1;
1483 }
1484
1485 static void add_pending_commit_list(struct rev_info *revs,
1486                                     struct commit_list *commit_list,
1487                                     unsigned int flags)
1488 {
1489         while (commit_list) {
1490                 struct object *object = &commit_list->item->object;
1491                 object->flags |= flags;
1492                 add_pending_object(revs, object, oid_to_hex(&object->oid));
1493                 commit_list = commit_list->next;
1494         }
1495 }
1496
1497 static void prepare_show_merge(struct rev_info *revs)
1498 {
1499         struct commit_list *bases;
1500         struct commit *head, *other;
1501         struct object_id oid;
1502         const char **prune = NULL;
1503         int i, prune_num = 1; /* counting terminating NULL */
1504         struct index_state *istate = revs->repo->index;
1505
1506         if (get_oid("HEAD", &oid))
1507                 die("--merge without HEAD?");
1508         head = lookup_commit_or_die(&oid, "HEAD");
1509         if (get_oid("MERGE_HEAD", &oid))
1510                 die("--merge without MERGE_HEAD?");
1511         other = lookup_commit_or_die(&oid, "MERGE_HEAD");
1512         add_pending_object(revs, &head->object, "HEAD");
1513         add_pending_object(revs, &other->object, "MERGE_HEAD");
1514         bases = get_merge_bases(head, other);
1515         add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
1516         add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
1517         free_commit_list(bases);
1518         head->object.flags |= SYMMETRIC_LEFT;
1519
1520         if (!istate->cache_nr)
1521                 read_index(istate);
1522         for (i = 0; i < istate->cache_nr; i++) {
1523                 const struct cache_entry *ce = istate->cache[i];
1524                 if (!ce_stage(ce))
1525                         continue;
1526                 if (ce_path_match(istate, ce, &revs->prune_data, NULL)) {
1527                         prune_num++;
1528                         REALLOC_ARRAY(prune, prune_num);
1529                         prune[prune_num-2] = ce->name;
1530                         prune[prune_num-1] = NULL;
1531                 }
1532                 while ((i+1 < istate->cache_nr) &&
1533                        ce_same_name(ce, istate->cache[i+1]))
1534                         i++;
1535         }
1536         clear_pathspec(&revs->prune_data);
1537         parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
1538                        PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
1539         revs->limited = 1;
1540 }
1541
1542 static int dotdot_missing(const char *arg, char *dotdot,
1543                           struct rev_info *revs, int symmetric)
1544 {
1545         if (revs->ignore_missing)
1546                 return 0;
1547         /* de-munge so we report the full argument */
1548         *dotdot = '.';
1549         die(symmetric
1550             ? "Invalid symmetric difference expression %s"
1551             : "Invalid revision range %s", arg);
1552 }
1553
1554 static int handle_dotdot_1(const char *arg, char *dotdot,
1555                            struct rev_info *revs, int flags,
1556                            int cant_be_filename,
1557                            struct object_context *a_oc,
1558                            struct object_context *b_oc)
1559 {
1560         const char *a_name, *b_name;
1561         struct object_id a_oid, b_oid;
1562         struct object *a_obj, *b_obj;
1563         unsigned int a_flags, b_flags;
1564         int symmetric = 0;
1565         unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
1566         unsigned int oc_flags = GET_OID_COMMITTISH | GET_OID_RECORD_PATH;
1567
1568         a_name = arg;
1569         if (!*a_name)
1570                 a_name = "HEAD";
1571
1572         b_name = dotdot + 2;
1573         if (*b_name == '.') {
1574                 symmetric = 1;
1575                 b_name++;
1576         }
1577         if (!*b_name)
1578                 b_name = "HEAD";
1579
1580         if (get_oid_with_context(a_name, oc_flags, &a_oid, a_oc) ||
1581             get_oid_with_context(b_name, oc_flags, &b_oid, b_oc))
1582                 return -1;
1583
1584         if (!cant_be_filename) {
1585                 *dotdot = '.';
1586                 verify_non_filename(revs->prefix, arg);
1587                 *dotdot = '\0';
1588         }
1589
1590         a_obj = parse_object(revs->repo, &a_oid);
1591         b_obj = parse_object(revs->repo, &b_oid);
1592         if (!a_obj || !b_obj)
1593                 return dotdot_missing(arg, dotdot, revs, symmetric);
1594
1595         if (!symmetric) {
1596                 /* just A..B */
1597                 b_flags = flags;
1598                 a_flags = flags_exclude;
1599         } else {
1600                 /* A...B -- find merge bases between the two */
1601                 struct commit *a, *b;
1602                 struct commit_list *exclude;
1603
1604                 a = lookup_commit_reference(revs->repo, &a_obj->oid);
1605                 b = lookup_commit_reference(revs->repo, &b_obj->oid);
1606                 if (!a || !b)
1607                         return dotdot_missing(arg, dotdot, revs, symmetric);
1608
1609                 exclude = get_merge_bases(a, b);
1610                 add_rev_cmdline_list(revs, exclude, REV_CMD_MERGE_BASE,
1611                                      flags_exclude);
1612                 add_pending_commit_list(revs, exclude, flags_exclude);
1613                 free_commit_list(exclude);
1614
1615                 b_flags = flags;
1616                 a_flags = flags | SYMMETRIC_LEFT;
1617         }
1618
1619         a_obj->flags |= a_flags;
1620         b_obj->flags |= b_flags;
1621         add_rev_cmdline(revs, a_obj, a_name, REV_CMD_LEFT, a_flags);
1622         add_rev_cmdline(revs, b_obj, b_name, REV_CMD_RIGHT, b_flags);
1623         add_pending_object_with_path(revs, a_obj, a_name, a_oc->mode, a_oc->path);
1624         add_pending_object_with_path(revs, b_obj, b_name, b_oc->mode, b_oc->path);
1625         return 0;
1626 }
1627
1628 static int handle_dotdot(const char *arg,
1629                          struct rev_info *revs, int flags,
1630                          int cant_be_filename)
1631 {
1632         struct object_context a_oc, b_oc;
1633         char *dotdot = strstr(arg, "..");
1634         int ret;
1635
1636         if (!dotdot)
1637                 return -1;
1638
1639         memset(&a_oc, 0, sizeof(a_oc));
1640         memset(&b_oc, 0, sizeof(b_oc));
1641
1642         *dotdot = '\0';
1643         ret = handle_dotdot_1(arg, dotdot, revs, flags, cant_be_filename,
1644                               &a_oc, &b_oc);
1645         *dotdot = '.';
1646
1647         free(a_oc.path);
1648         free(b_oc.path);
1649
1650         return ret;
1651 }
1652
1653 int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
1654 {
1655         struct object_context oc;
1656         char *mark;
1657         struct object *object;
1658         struct object_id oid;
1659         int local_flags;
1660         const char *arg = arg_;
1661         int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
1662         unsigned get_sha1_flags = GET_OID_RECORD_PATH;
1663
1664         flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
1665
1666         if (!cant_be_filename && !strcmp(arg, "..")) {
1667                 /*
1668                  * Just ".."?  That is not a range but the
1669                  * pathspec for the parent directory.
1670                  */
1671                 return -1;
1672         }
1673
1674         if (!handle_dotdot(arg, revs, flags, revarg_opt))
1675                 return 0;
1676
1677         mark = strstr(arg, "^@");
1678         if (mark && !mark[2]) {
1679                 *mark = 0;
1680                 if (add_parents_only(revs, arg, flags, 0))
1681                         return 0;
1682                 *mark = '^';
1683         }
1684         mark = strstr(arg, "^!");
1685         if (mark && !mark[2]) {
1686                 *mark = 0;
1687                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), 0))
1688                         *mark = '^';
1689         }
1690         mark = strstr(arg, "^-");
1691         if (mark) {
1692                 int exclude_parent = 1;
1693
1694                 if (mark[2]) {
1695                         char *end;
1696                         exclude_parent = strtoul(mark + 2, &end, 10);
1697                         if (*end != '\0' || !exclude_parent)
1698                                 return -1;
1699                 }
1700
1701                 *mark = 0;
1702                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), exclude_parent))
1703                         *mark = '^';
1704         }
1705
1706         local_flags = 0;
1707         if (*arg == '^') {
1708                 local_flags = UNINTERESTING | BOTTOM;
1709                 arg++;
1710         }
1711
1712         if (revarg_opt & REVARG_COMMITTISH)
1713                 get_sha1_flags |= GET_OID_COMMITTISH;
1714
1715         if (get_oid_with_context(arg, get_sha1_flags, &oid, &oc))
1716                 return revs->ignore_missing ? 0 : -1;
1717         if (!cant_be_filename)
1718                 verify_non_filename(revs->prefix, arg);
1719         object = get_reference(revs, arg, &oid, flags ^ local_flags);
1720         add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
1721         add_pending_object_with_path(revs, object, arg, oc.mode, oc.path);
1722         free(oc.path);
1723         return 0;
1724 }
1725
1726 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
1727                                      struct argv_array *prune)
1728 {
1729         while (strbuf_getline(sb, stdin) != EOF)
1730                 argv_array_push(prune, sb->buf);
1731 }
1732
1733 static void read_revisions_from_stdin(struct rev_info *revs,
1734                                       struct argv_array *prune)
1735 {
1736         struct strbuf sb;
1737         int seen_dashdash = 0;
1738         int save_warning;
1739
1740         save_warning = warn_on_object_refname_ambiguity;
1741         warn_on_object_refname_ambiguity = 0;
1742
1743         strbuf_init(&sb, 1000);
1744         while (strbuf_getline(&sb, stdin) != EOF) {
1745                 int len = sb.len;
1746                 if (!len)
1747                         break;
1748                 if (sb.buf[0] == '-') {
1749                         if (len == 2 && sb.buf[1] == '-') {
1750                                 seen_dashdash = 1;
1751                                 break;
1752                         }
1753                         die("options not supported in --stdin mode");
1754                 }
1755                 if (handle_revision_arg(sb.buf, revs, 0,
1756                                         REVARG_CANNOT_BE_FILENAME))
1757                         die("bad revision '%s'", sb.buf);
1758         }
1759         if (seen_dashdash)
1760                 read_pathspec_from_stdin(revs, &sb, prune);
1761
1762         strbuf_release(&sb);
1763         warn_on_object_refname_ambiguity = save_warning;
1764 }
1765
1766 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1767 {
1768         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1769 }
1770
1771 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1772 {
1773         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1774 }
1775
1776 static void add_message_grep(struct rev_info *revs, const char *pattern)
1777 {
1778         add_grep(revs, pattern, GREP_PATTERN_BODY);
1779 }
1780
1781 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1782                                int *unkc, const char **unkv)
1783 {
1784         const char *arg = argv[0];
1785         const char *optarg;
1786         int argcount;
1787         const unsigned hexsz = the_hash_algo->hexsz;
1788
1789         /* pseudo revision arguments */
1790         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1791             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1792             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1793             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1794             !strcmp(arg, "--bisect") || starts_with(arg, "--glob=") ||
1795             !strcmp(arg, "--indexed-objects") ||
1796             starts_with(arg, "--exclude=") ||
1797             starts_with(arg, "--branches=") || starts_with(arg, "--tags=") ||
1798             starts_with(arg, "--remotes=") || starts_with(arg, "--no-walk="))
1799         {
1800                 unkv[(*unkc)++] = arg;
1801                 return 1;
1802         }
1803
1804         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1805                 revs->max_count = atoi(optarg);
1806                 revs->no_walk = 0;
1807                 return argcount;
1808         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1809                 revs->skip_count = atoi(optarg);
1810                 return argcount;
1811         } else if ((*arg == '-') && isdigit(arg[1])) {
1812                 /* accept -<digit>, like traditional "head" */
1813                 if (strtol_i(arg + 1, 10, &revs->max_count) < 0 ||
1814                     revs->max_count < 0)
1815                         die("'%s': not a non-negative integer", arg + 1);
1816                 revs->no_walk = 0;
1817         } else if (!strcmp(arg, "-n")) {
1818                 if (argc <= 1)
1819                         return error("-n requires an argument");
1820                 revs->max_count = atoi(argv[1]);
1821                 revs->no_walk = 0;
1822                 return 2;
1823         } else if (skip_prefix(arg, "-n", &optarg)) {
1824                 revs->max_count = atoi(optarg);
1825                 revs->no_walk = 0;
1826         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1827                 revs->max_age = atoi(optarg);
1828                 return argcount;
1829         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1830                 revs->max_age = approxidate(optarg);
1831                 return argcount;
1832         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1833                 revs->max_age = approxidate(optarg);
1834                 return argcount;
1835         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1836                 revs->min_age = atoi(optarg);
1837                 return argcount;
1838         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1839                 revs->min_age = approxidate(optarg);
1840                 return argcount;
1841         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1842                 revs->min_age = approxidate(optarg);
1843                 return argcount;
1844         } else if (!strcmp(arg, "--first-parent")) {
1845                 revs->first_parent_only = 1;
1846         } else if (!strcmp(arg, "--ancestry-path")) {
1847                 revs->ancestry_path = 1;
1848                 revs->simplify_history = 0;
1849                 revs->limited = 1;
1850         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1851                 init_reflog_walk(&revs->reflog_info);
1852         } else if (!strcmp(arg, "--default")) {
1853                 if (argc <= 1)
1854                         return error("bad --default argument");
1855                 revs->def = argv[1];
1856                 return 2;
1857         } else if (!strcmp(arg, "--merge")) {
1858                 revs->show_merge = 1;
1859         } else if (!strcmp(arg, "--topo-order")) {
1860                 revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1861                 revs->topo_order = 1;
1862         } else if (!strcmp(arg, "--simplify-merges")) {
1863                 revs->simplify_merges = 1;
1864                 revs->topo_order = 1;
1865                 revs->rewrite_parents = 1;
1866                 revs->simplify_history = 0;
1867                 revs->limited = 1;
1868         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1869                 revs->simplify_merges = 1;
1870                 revs->topo_order = 1;
1871                 revs->rewrite_parents = 1;
1872                 revs->simplify_history = 0;
1873                 revs->simplify_by_decoration = 1;
1874                 revs->limited = 1;
1875                 revs->prune = 1;
1876                 load_ref_decorations(NULL, DECORATE_SHORT_REFS);
1877         } else if (!strcmp(arg, "--date-order")) {
1878                 revs->sort_order = REV_SORT_BY_COMMIT_DATE;
1879                 revs->topo_order = 1;
1880         } else if (!strcmp(arg, "--author-date-order")) {
1881                 revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
1882                 revs->topo_order = 1;
1883         } else if (!strcmp(arg, "--early-output")) {
1884                 revs->early_output = 100;
1885                 revs->topo_order = 1;
1886         } else if (skip_prefix(arg, "--early-output=", &optarg)) {
1887                 if (strtoul_ui(optarg, 10, &revs->early_output) < 0)
1888                         die("'%s': not a non-negative integer", optarg);
1889                 revs->topo_order = 1;
1890         } else if (!strcmp(arg, "--parents")) {
1891                 revs->rewrite_parents = 1;
1892                 revs->print_parents = 1;
1893         } else if (!strcmp(arg, "--dense")) {
1894                 revs->dense = 1;
1895         } else if (!strcmp(arg, "--sparse")) {
1896                 revs->dense = 0;
1897         } else if (!strcmp(arg, "--in-commit-order")) {
1898                 revs->tree_blobs_in_commit_order = 1;
1899         } else if (!strcmp(arg, "--remove-empty")) {
1900                 revs->remove_empty_trees = 1;
1901         } else if (!strcmp(arg, "--merges")) {
1902                 revs->min_parents = 2;
1903         } else if (!strcmp(arg, "--no-merges")) {
1904                 revs->max_parents = 1;
1905         } else if (skip_prefix(arg, "--min-parents=", &optarg)) {
1906                 revs->min_parents = atoi(optarg);
1907         } else if (!strcmp(arg, "--no-min-parents")) {
1908                 revs->min_parents = 0;
1909         } else if (skip_prefix(arg, "--max-parents=", &optarg)) {
1910                 revs->max_parents = atoi(optarg);
1911         } else if (!strcmp(arg, "--no-max-parents")) {
1912                 revs->max_parents = -1;
1913         } else if (!strcmp(arg, "--boundary")) {
1914                 revs->boundary = 1;
1915         } else if (!strcmp(arg, "--left-right")) {
1916                 revs->left_right = 1;
1917         } else if (!strcmp(arg, "--left-only")) {
1918                 if (revs->right_only)
1919                         die("--left-only is incompatible with --right-only"
1920                             " or --cherry");
1921                 revs->left_only = 1;
1922         } else if (!strcmp(arg, "--right-only")) {
1923                 if (revs->left_only)
1924                         die("--right-only is incompatible with --left-only");
1925                 revs->right_only = 1;
1926         } else if (!strcmp(arg, "--cherry")) {
1927                 if (revs->left_only)
1928                         die("--cherry is incompatible with --left-only");
1929                 revs->cherry_mark = 1;
1930                 revs->right_only = 1;
1931                 revs->max_parents = 1;
1932                 revs->limited = 1;
1933         } else if (!strcmp(arg, "--count")) {
1934                 revs->count = 1;
1935         } else if (!strcmp(arg, "--cherry-mark")) {
1936                 if (revs->cherry_pick)
1937                         die("--cherry-mark is incompatible with --cherry-pick");
1938                 revs->cherry_mark = 1;
1939                 revs->limited = 1; /* needs limit_list() */
1940         } else if (!strcmp(arg, "--cherry-pick")) {
1941                 if (revs->cherry_mark)
1942                         die("--cherry-pick is incompatible with --cherry-mark");
1943                 revs->cherry_pick = 1;
1944                 revs->limited = 1;
1945         } else if (!strcmp(arg, "--objects")) {
1946                 revs->tag_objects = 1;
1947                 revs->tree_objects = 1;
1948                 revs->blob_objects = 1;
1949         } else if (!strcmp(arg, "--objects-edge")) {
1950                 revs->tag_objects = 1;
1951                 revs->tree_objects = 1;
1952                 revs->blob_objects = 1;
1953                 revs->edge_hint = 1;
1954         } else if (!strcmp(arg, "--objects-edge-aggressive")) {
1955                 revs->tag_objects = 1;
1956                 revs->tree_objects = 1;
1957                 revs->blob_objects = 1;
1958                 revs->edge_hint = 1;
1959                 revs->edge_hint_aggressive = 1;
1960         } else if (!strcmp(arg, "--verify-objects")) {
1961                 revs->tag_objects = 1;
1962                 revs->tree_objects = 1;
1963                 revs->blob_objects = 1;
1964                 revs->verify_objects = 1;
1965         } else if (!strcmp(arg, "--unpacked")) {
1966                 revs->unpacked = 1;
1967         } else if (starts_with(arg, "--unpacked=")) {
1968                 die("--unpacked=<packfile> no longer supported.");
1969         } else if (!strcmp(arg, "-r")) {
1970                 revs->diff = 1;
1971                 revs->diffopt.flags.recursive = 1;
1972         } else if (!strcmp(arg, "-t")) {
1973                 revs->diff = 1;
1974                 revs->diffopt.flags.recursive = 1;
1975                 revs->diffopt.flags.tree_in_recursive = 1;
1976         } else if (!strcmp(arg, "-m")) {
1977                 revs->ignore_merges = 0;
1978         } else if (!strcmp(arg, "-c")) {
1979                 revs->diff = 1;
1980                 revs->dense_combined_merges = 0;
1981                 revs->combine_merges = 1;
1982         } else if (!strcmp(arg, "--cc")) {
1983                 revs->diff = 1;
1984                 revs->dense_combined_merges = 1;
1985                 revs->combine_merges = 1;
1986         } else if (!strcmp(arg, "-v")) {
1987                 revs->verbose_header = 1;
1988         } else if (!strcmp(arg, "--pretty")) {
1989                 revs->verbose_header = 1;
1990                 revs->pretty_given = 1;
1991                 get_commit_format(NULL, revs);
1992         } else if (skip_prefix(arg, "--pretty=", &optarg) ||
1993                    skip_prefix(arg, "--format=", &optarg)) {
1994                 /*
1995                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1996                  * not allowed, since the argument is optional.
1997                  */
1998                 revs->verbose_header = 1;
1999                 revs->pretty_given = 1;
2000                 get_commit_format(optarg, revs);
2001         } else if (!strcmp(arg, "--expand-tabs")) {
2002                 revs->expand_tabs_in_log = 8;
2003         } else if (!strcmp(arg, "--no-expand-tabs")) {
2004                 revs->expand_tabs_in_log = 0;
2005         } else if (skip_prefix(arg, "--expand-tabs=", &arg)) {
2006                 int val;
2007                 if (strtol_i(arg, 10, &val) < 0 || val < 0)
2008                         die("'%s': not a non-negative integer", arg);
2009                 revs->expand_tabs_in_log = val;
2010         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
2011                 revs->show_notes = 1;
2012                 revs->show_notes_given = 1;
2013                 revs->notes_opt.use_default_notes = 1;
2014         } else if (!strcmp(arg, "--show-signature")) {
2015                 revs->show_signature = 1;
2016         } else if (!strcmp(arg, "--no-show-signature")) {
2017                 revs->show_signature = 0;
2018         } else if (!strcmp(arg, "--show-linear-break")) {
2019                 revs->break_bar = "                    ..........";
2020                 revs->track_linear = 1;
2021                 revs->track_first_time = 1;
2022         } else if (skip_prefix(arg, "--show-linear-break=", &optarg)) {
2023                 revs->break_bar = xstrdup(optarg);
2024                 revs->track_linear = 1;
2025                 revs->track_first_time = 1;
2026         } else if (skip_prefix(arg, "--show-notes=", &optarg) ||
2027                    skip_prefix(arg, "--notes=", &optarg)) {
2028                 struct strbuf buf = STRBUF_INIT;
2029                 revs->show_notes = 1;
2030                 revs->show_notes_given = 1;
2031                 if (starts_with(arg, "--show-notes=") &&
2032                     revs->notes_opt.use_default_notes < 0)
2033                         revs->notes_opt.use_default_notes = 1;
2034                 strbuf_addstr(&buf, optarg);
2035                 expand_notes_ref(&buf);
2036                 string_list_append(&revs->notes_opt.extra_notes_refs,
2037                                    strbuf_detach(&buf, NULL));
2038         } else if (!strcmp(arg, "--no-notes")) {
2039                 revs->show_notes = 0;
2040                 revs->show_notes_given = 1;
2041                 revs->notes_opt.use_default_notes = -1;
2042                 /* we have been strdup'ing ourselves, so trick
2043                  * string_list into free()ing strings */
2044                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
2045                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
2046                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
2047         } else if (!strcmp(arg, "--standard-notes")) {
2048                 revs->show_notes_given = 1;
2049                 revs->notes_opt.use_default_notes = 1;
2050         } else if (!strcmp(arg, "--no-standard-notes")) {
2051                 revs->notes_opt.use_default_notes = 0;
2052         } else if (!strcmp(arg, "--oneline")) {
2053                 revs->verbose_header = 1;
2054                 get_commit_format("oneline", revs);
2055                 revs->pretty_given = 1;
2056                 revs->abbrev_commit = 1;
2057         } else if (!strcmp(arg, "--graph")) {
2058                 revs->topo_order = 1;
2059                 revs->rewrite_parents = 1;
2060                 revs->graph = graph_init(revs);
2061         } else if (!strcmp(arg, "--root")) {
2062                 revs->show_root_diff = 1;
2063         } else if (!strcmp(arg, "--no-commit-id")) {
2064                 revs->no_commit_id = 1;
2065         } else if (!strcmp(arg, "--always")) {
2066                 revs->always_show_header = 1;
2067         } else if (!strcmp(arg, "--no-abbrev")) {
2068                 revs->abbrev = 0;
2069         } else if (!strcmp(arg, "--abbrev")) {
2070                 revs->abbrev = DEFAULT_ABBREV;
2071         } else if (skip_prefix(arg, "--abbrev=", &optarg)) {
2072                 revs->abbrev = strtoul(optarg, NULL, 10);
2073                 if (revs->abbrev < MINIMUM_ABBREV)
2074                         revs->abbrev = MINIMUM_ABBREV;
2075                 else if (revs->abbrev > hexsz)
2076                         revs->abbrev = hexsz;
2077         } else if (!strcmp(arg, "--abbrev-commit")) {
2078                 revs->abbrev_commit = 1;
2079                 revs->abbrev_commit_given = 1;
2080         } else if (!strcmp(arg, "--no-abbrev-commit")) {
2081                 revs->abbrev_commit = 0;
2082         } else if (!strcmp(arg, "--full-diff")) {
2083                 revs->diff = 1;
2084                 revs->full_diff = 1;
2085         } else if (!strcmp(arg, "--full-history")) {
2086                 revs->simplify_history = 0;
2087         } else if (!strcmp(arg, "--relative-date")) {
2088                 revs->date_mode.type = DATE_RELATIVE;
2089                 revs->date_mode_explicit = 1;
2090         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
2091                 parse_date_format(optarg, &revs->date_mode);
2092                 revs->date_mode_explicit = 1;
2093                 return argcount;
2094         } else if (!strcmp(arg, "--log-size")) {
2095                 revs->show_log_size = 1;
2096         }
2097         /*
2098          * Grepping the commit log
2099          */
2100         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
2101                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
2102                 return argcount;
2103         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
2104                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
2105                 return argcount;
2106         } else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
2107                 add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
2108                 return argcount;
2109         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
2110                 add_message_grep(revs, optarg);
2111                 return argcount;
2112         } else if (!strcmp(arg, "--grep-debug")) {
2113                 revs->grep_filter.debug = 1;
2114         } else if (!strcmp(arg, "--basic-regexp")) {
2115                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_BRE;
2116         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
2117                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_ERE;
2118         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
2119                 revs->grep_filter.ignore_case = 1;
2120                 revs->diffopt.pickaxe_opts |= DIFF_PICKAXE_IGNORE_CASE;
2121         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
2122                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_FIXED;
2123         } else if (!strcmp(arg, "--perl-regexp") || !strcmp(arg, "-P")) {
2124                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_PCRE;
2125         } else if (!strcmp(arg, "--all-match")) {
2126                 revs->grep_filter.all_match = 1;
2127         } else if (!strcmp(arg, "--invert-grep")) {
2128                 revs->invert_grep = 1;
2129         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
2130                 if (strcmp(optarg, "none"))
2131                         git_log_output_encoding = xstrdup(optarg);
2132                 else
2133                         git_log_output_encoding = "";
2134                 return argcount;
2135         } else if (!strcmp(arg, "--reverse")) {
2136                 revs->reverse ^= 1;
2137         } else if (!strcmp(arg, "--children")) {
2138                 revs->children.name = "children";
2139                 revs->limited = 1;
2140         } else if (!strcmp(arg, "--ignore-missing")) {
2141                 revs->ignore_missing = 1;
2142         } else if (!strcmp(arg, "--exclude-promisor-objects")) {
2143                 if (fetch_if_missing)
2144                         BUG("exclude_promisor_objects can only be used when fetch_if_missing is 0");
2145                 revs->exclude_promisor_objects = 1;
2146         } else {
2147                 int opts = diff_opt_parse(&revs->diffopt, argv, argc, revs->prefix);
2148                 if (!opts)
2149                         unkv[(*unkc)++] = arg;
2150                 return opts;
2151         }
2152         if (revs->graph && revs->track_linear)
2153                 die("--show-linear-break and --graph are incompatible");
2154
2155         return 1;
2156 }
2157
2158 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
2159                         const struct option *options,
2160                         const char * const usagestr[])
2161 {
2162         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
2163                                     &ctx->cpidx, ctx->out);
2164         if (n <= 0) {
2165                 error("unknown option `%s'", ctx->argv[0]);
2166                 usage_with_options(usagestr, options);
2167         }
2168         ctx->argv += n;
2169         ctx->argc -= n;
2170 }
2171
2172 static int for_each_bisect_ref(struct ref_store *refs, each_ref_fn fn,
2173                                void *cb_data, const char *term)
2174 {
2175         struct strbuf bisect_refs = STRBUF_INIT;
2176         int status;
2177         strbuf_addf(&bisect_refs, "refs/bisect/%s", term);
2178         status = refs_for_each_fullref_in(refs, bisect_refs.buf, fn, cb_data, 0);
2179         strbuf_release(&bisect_refs);
2180         return status;
2181 }
2182
2183 static int for_each_bad_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2184 {
2185         return for_each_bisect_ref(refs, fn, cb_data, term_bad);
2186 }
2187
2188 static int for_each_good_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2189 {
2190         return for_each_bisect_ref(refs, fn, cb_data, term_good);
2191 }
2192
2193 static int handle_revision_pseudo_opt(const char *submodule,
2194                                 struct rev_info *revs,
2195                                 int argc, const char **argv, int *flags)
2196 {
2197         const char *arg = argv[0];
2198         const char *optarg;
2199         struct ref_store *refs;
2200         int argcount;
2201
2202         if (submodule) {
2203                 /*
2204                  * We need some something like get_submodule_worktrees()
2205                  * before we can go through all worktrees of a submodule,
2206                  * .e.g with adding all HEADs from --all, which is not
2207                  * supported right now, so stick to single worktree.
2208                  */
2209                 if (!revs->single_worktree)
2210                         BUG("--single-worktree cannot be used together with submodule");
2211                 refs = get_submodule_ref_store(submodule);
2212         } else
2213                 refs = get_main_ref_store(revs->repo);
2214
2215         /*
2216          * NOTE!
2217          *
2218          * Commands like "git shortlog" will not accept the options below
2219          * unless parse_revision_opt queues them (as opposed to erroring
2220          * out).
2221          *
2222          * When implementing your new pseudo-option, remember to
2223          * register it in the list at the top of handle_revision_opt.
2224          */
2225         if (!strcmp(arg, "--all")) {
2226                 handle_refs(refs, revs, *flags, refs_for_each_ref);
2227                 handle_refs(refs, revs, *flags, refs_head_ref);
2228                 if (!revs->single_worktree) {
2229                         struct all_refs_cb cb;
2230
2231                         init_all_refs_cb(&cb, revs, *flags);
2232                         other_head_refs(handle_one_ref, &cb);
2233                 }
2234                 clear_ref_exclusion(&revs->ref_excludes);
2235         } else if (!strcmp(arg, "--branches")) {
2236                 handle_refs(refs, revs, *flags, refs_for_each_branch_ref);
2237                 clear_ref_exclusion(&revs->ref_excludes);
2238         } else if (!strcmp(arg, "--bisect")) {
2239                 read_bisect_terms(&term_bad, &term_good);
2240                 handle_refs(refs, revs, *flags, for_each_bad_bisect_ref);
2241                 handle_refs(refs, revs, *flags ^ (UNINTERESTING | BOTTOM),
2242                             for_each_good_bisect_ref);
2243                 revs->bisect = 1;
2244         } else if (!strcmp(arg, "--tags")) {
2245                 handle_refs(refs, revs, *flags, refs_for_each_tag_ref);
2246                 clear_ref_exclusion(&revs->ref_excludes);
2247         } else if (!strcmp(arg, "--remotes")) {
2248                 handle_refs(refs, revs, *flags, refs_for_each_remote_ref);
2249                 clear_ref_exclusion(&revs->ref_excludes);
2250         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
2251                 struct all_refs_cb cb;
2252                 init_all_refs_cb(&cb, revs, *flags);
2253                 for_each_glob_ref(handle_one_ref, optarg, &cb);
2254                 clear_ref_exclusion(&revs->ref_excludes);
2255                 return argcount;
2256         } else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
2257                 add_ref_exclusion(&revs->ref_excludes, optarg);
2258                 return argcount;
2259         } else if (skip_prefix(arg, "--branches=", &optarg)) {
2260                 struct all_refs_cb cb;
2261                 init_all_refs_cb(&cb, revs, *flags);
2262                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/heads/", &cb);
2263                 clear_ref_exclusion(&revs->ref_excludes);
2264         } else if (skip_prefix(arg, "--tags=", &optarg)) {
2265                 struct all_refs_cb cb;
2266                 init_all_refs_cb(&cb, revs, *flags);
2267                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/tags/", &cb);
2268                 clear_ref_exclusion(&revs->ref_excludes);
2269         } else if (skip_prefix(arg, "--remotes=", &optarg)) {
2270                 struct all_refs_cb cb;
2271                 init_all_refs_cb(&cb, revs, *flags);
2272                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/remotes/", &cb);
2273                 clear_ref_exclusion(&revs->ref_excludes);
2274         } else if (!strcmp(arg, "--reflog")) {
2275                 add_reflogs_to_pending(revs, *flags);
2276         } else if (!strcmp(arg, "--indexed-objects")) {
2277                 add_index_objects_to_pending(revs, *flags);
2278         } else if (!strcmp(arg, "--not")) {
2279                 *flags ^= UNINTERESTING | BOTTOM;
2280         } else if (!strcmp(arg, "--no-walk")) {
2281                 revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2282         } else if (skip_prefix(arg, "--no-walk=", &optarg)) {
2283                 /*
2284                  * Detached form ("--no-walk X" as opposed to "--no-walk=X")
2285                  * not allowed, since the argument is optional.
2286                  */
2287                 if (!strcmp(optarg, "sorted"))
2288                         revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2289                 else if (!strcmp(optarg, "unsorted"))
2290                         revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
2291                 else
2292                         return error("invalid argument to --no-walk");
2293         } else if (!strcmp(arg, "--do-walk")) {
2294                 revs->no_walk = 0;
2295         } else if (!strcmp(arg, "--single-worktree")) {
2296                 revs->single_worktree = 1;
2297         } else {
2298                 return 0;
2299         }
2300
2301         return 1;
2302 }
2303
2304 static void NORETURN diagnose_missing_default(const char *def)
2305 {
2306         int flags;
2307         const char *refname;
2308
2309         refname = resolve_ref_unsafe(def, 0, NULL, &flags);
2310         if (!refname || !(flags & REF_ISSYMREF) || (flags & REF_ISBROKEN))
2311                 die(_("your current branch appears to be broken"));
2312
2313         skip_prefix(refname, "refs/heads/", &refname);
2314         die(_("your current branch '%s' does not have any commits yet"),
2315             refname);
2316 }
2317
2318 /*
2319  * Parse revision information, filling in the "rev_info" structure,
2320  * and removing the used arguments from the argument list.
2321  *
2322  * Returns the number of arguments left that weren't recognized
2323  * (which are also moved to the head of the argument list)
2324  */
2325 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
2326 {
2327         int i, flags, left, seen_dashdash, got_rev_arg = 0, revarg_opt;
2328         struct argv_array prune_data = ARGV_ARRAY_INIT;
2329         const char *submodule = NULL;
2330
2331         if (opt)
2332                 submodule = opt->submodule;
2333
2334         /* First, search for "--" */
2335         if (opt && opt->assume_dashdash) {
2336                 seen_dashdash = 1;
2337         } else {
2338                 seen_dashdash = 0;
2339                 for (i = 1; i < argc; i++) {
2340                         const char *arg = argv[i];
2341                         if (strcmp(arg, "--"))
2342                                 continue;
2343                         argv[i] = NULL;
2344                         argc = i;
2345                         if (argv[i + 1])
2346                                 argv_array_pushv(&prune_data, argv + i + 1);
2347                         seen_dashdash = 1;
2348                         break;
2349                 }
2350         }
2351
2352         /* Second, deal with arguments and options */
2353         flags = 0;
2354         revarg_opt = opt ? opt->revarg_opt : 0;
2355         if (seen_dashdash)
2356                 revarg_opt |= REVARG_CANNOT_BE_FILENAME;
2357         for (left = i = 1; i < argc; i++) {
2358                 const char *arg = argv[i];
2359                 if (*arg == '-') {
2360                         int opts;
2361
2362                         opts = handle_revision_pseudo_opt(submodule,
2363                                                 revs, argc - i, argv + i,
2364                                                 &flags);
2365                         if (opts > 0) {
2366                                 i += opts - 1;
2367                                 continue;
2368                         }
2369
2370                         if (!strcmp(arg, "--stdin")) {
2371                                 if (revs->disable_stdin) {
2372                                         argv[left++] = arg;
2373                                         continue;
2374                                 }
2375                                 if (revs->read_from_stdin++)
2376                                         die("--stdin given twice?");
2377                                 read_revisions_from_stdin(revs, &prune_data);
2378                                 continue;
2379                         }
2380
2381                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
2382                         if (opts > 0) {
2383                                 i += opts - 1;
2384                                 continue;
2385                         }
2386                         if (opts < 0)
2387                                 exit(128);
2388                         continue;
2389                 }
2390
2391
2392                 if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
2393                         int j;
2394                         if (seen_dashdash || *arg == '^')
2395                                 die("bad revision '%s'", arg);
2396
2397                         /* If we didn't have a "--":
2398                          * (1) all filenames must exist;
2399                          * (2) all rev-args must not be interpretable
2400                          *     as a valid filename.
2401                          * but the latter we have checked in the main loop.
2402                          */
2403                         for (j = i; j < argc; j++)
2404                                 verify_filename(revs->prefix, argv[j], j == i);
2405
2406                         argv_array_pushv(&prune_data, argv + i);
2407                         break;
2408                 }
2409                 else
2410                         got_rev_arg = 1;
2411         }
2412
2413         if (prune_data.argc) {
2414                 /*
2415                  * If we need to introduce the magic "a lone ':' means no
2416                  * pathspec whatsoever", here is the place to do so.
2417                  *
2418                  * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
2419                  *      prune_data.nr = 0;
2420                  *      prune_data.alloc = 0;
2421                  *      free(prune_data.path);
2422                  *      prune_data.path = NULL;
2423                  * } else {
2424                  *      terminate prune_data.alloc with NULL and
2425                  *      call init_pathspec() to set revs->prune_data here.
2426                  * }
2427                  */
2428                 parse_pathspec(&revs->prune_data, 0, 0,
2429                                revs->prefix, prune_data.argv);
2430         }
2431         argv_array_clear(&prune_data);
2432
2433         if (revs->def == NULL)
2434                 revs->def = opt ? opt->def : NULL;
2435         if (opt && opt->tweak)
2436                 opt->tweak(revs, opt);
2437         if (revs->show_merge)
2438                 prepare_show_merge(revs);
2439         if (revs->def && !revs->pending.nr && !revs->rev_input_given && !got_rev_arg) {
2440                 struct object_id oid;
2441                 struct object *object;
2442                 struct object_context oc;
2443                 if (get_oid_with_context(revs->def, 0, &oid, &oc))
2444                         diagnose_missing_default(revs->def);
2445                 object = get_reference(revs, revs->def, &oid, 0);
2446                 add_pending_object_with_mode(revs, object, revs->def, oc.mode);
2447         }
2448
2449         /* Did the user ask for any diff output? Run the diff! */
2450         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
2451                 revs->diff = 1;
2452
2453         /* Pickaxe, diff-filter and rename following need diffs */
2454         if ((revs->diffopt.pickaxe_opts & DIFF_PICKAXE_KINDS_MASK) ||
2455             revs->diffopt.filter ||
2456             revs->diffopt.flags.follow_renames)
2457                 revs->diff = 1;
2458
2459         if (revs->diffopt.objfind)
2460                 revs->simplify_history = 0;
2461
2462         if (revs->topo_order)
2463                 revs->limited = 1;
2464
2465         if (revs->prune_data.nr) {
2466                 copy_pathspec(&revs->pruning.pathspec, &revs->prune_data);
2467                 /* Can't prune commits with rename following: the paths change.. */
2468                 if (!revs->diffopt.flags.follow_renames)
2469                         revs->prune = 1;
2470                 if (!revs->full_diff)
2471                         copy_pathspec(&revs->diffopt.pathspec,
2472                                       &revs->prune_data);
2473         }
2474         if (revs->combine_merges)
2475                 revs->ignore_merges = 0;
2476         revs->diffopt.abbrev = revs->abbrev;
2477
2478         if (revs->line_level_traverse) {
2479                 revs->limited = 1;
2480                 revs->topo_order = 1;
2481         }
2482
2483         diff_setup_done(&revs->diffopt);
2484
2485         grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
2486                                  &revs->grep_filter);
2487         compile_grep_patterns(&revs->grep_filter);
2488
2489         if (revs->reverse && revs->reflog_info)
2490                 die("cannot combine --reverse with --walk-reflogs");
2491         if (revs->reflog_info && revs->limited)
2492                 die("cannot combine --walk-reflogs with history-limiting options");
2493         if (revs->rewrite_parents && revs->children.name)
2494                 die("cannot combine --parents and --children");
2495
2496         /*
2497          * Limitations on the graph functionality
2498          */
2499         if (revs->reverse && revs->graph)
2500                 die("cannot combine --reverse with --graph");
2501
2502         if (revs->reflog_info && revs->graph)
2503                 die("cannot combine --walk-reflogs with --graph");
2504         if (revs->no_walk && revs->graph)
2505                 die("cannot combine --no-walk with --graph");
2506         if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
2507                 die("cannot use --grep-reflog without --walk-reflogs");
2508
2509         if (revs->first_parent_only && revs->bisect)
2510                 die(_("--first-parent is incompatible with --bisect"));
2511
2512         if (revs->expand_tabs_in_log < 0)
2513                 revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;
2514
2515         return left;
2516 }
2517
2518 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
2519 {
2520         struct commit_list *l = xcalloc(1, sizeof(*l));
2521
2522         l->item = child;
2523         l->next = add_decoration(&revs->children, &parent->object, l);
2524 }
2525
2526 static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
2527 {
2528         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2529         struct commit_list **pp, *p;
2530         int surviving_parents;
2531
2532         /* Examine existing parents while marking ones we have seen... */
2533         pp = &commit->parents;
2534         surviving_parents = 0;
2535         while ((p = *pp) != NULL) {
2536                 struct commit *parent = p->item;
2537                 if (parent->object.flags & TMP_MARK) {
2538                         *pp = p->next;
2539                         if (ts)
2540                                 compact_treesame(revs, commit, surviving_parents);
2541                         continue;
2542                 }
2543                 parent->object.flags |= TMP_MARK;
2544                 surviving_parents++;
2545                 pp = &p->next;
2546         }
2547         /* clear the temporary mark */
2548         for (p = commit->parents; p; p = p->next) {
2549                 p->item->object.flags &= ~TMP_MARK;
2550         }
2551         /* no update_treesame() - removing duplicates can't affect TREESAME */
2552         return surviving_parents;
2553 }
2554
2555 struct merge_simplify_state {
2556         struct commit *simplified;
2557 };
2558
2559 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
2560 {
2561         struct merge_simplify_state *st;
2562
2563         st = lookup_decoration(&revs->merge_simplification, &commit->object);
2564         if (!st) {
2565                 st = xcalloc(1, sizeof(*st));
2566                 add_decoration(&revs->merge_simplification, &commit->object, st);
2567         }
2568         return st;
2569 }
2570
2571 static int mark_redundant_parents(struct rev_info *revs, struct commit *commit)
2572 {
2573         struct commit_list *h = reduce_heads(commit->parents);
2574         int i = 0, marked = 0;
2575         struct commit_list *po, *pn;
2576
2577         /* Want these for sanity-checking only */
2578         int orig_cnt = commit_list_count(commit->parents);
2579         int cnt = commit_list_count(h);
2580
2581         /*
2582          * Not ready to remove items yet, just mark them for now, based
2583          * on the output of reduce_heads(). reduce_heads outputs the reduced
2584          * set in its original order, so this isn't too hard.
2585          */
2586         po = commit->parents;
2587         pn = h;
2588         while (po) {
2589                 if (pn && po->item == pn->item) {
2590                         pn = pn->next;
2591                         i++;
2592                 } else {
2593                         po->item->object.flags |= TMP_MARK;
2594                         marked++;
2595                 }
2596                 po=po->next;
2597         }
2598
2599         if (i != cnt || cnt+marked != orig_cnt)
2600                 die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
2601
2602         free_commit_list(h);
2603
2604         return marked;
2605 }
2606
2607 static int mark_treesame_root_parents(struct rev_info *revs, struct commit *commit)
2608 {
2609         struct commit_list *p;
2610         int marked = 0;
2611
2612         for (p = commit->parents; p; p = p->next) {
2613                 struct commit *parent = p->item;
2614                 if (!parent->parents && (parent->object.flags & TREESAME)) {
2615                         parent->object.flags |= TMP_MARK;
2616                         marked++;
2617                 }
2618         }
2619
2620         return marked;
2621 }
2622
2623 /*
2624  * Awkward naming - this means one parent we are TREESAME to.
2625  * cf mark_treesame_root_parents: root parents that are TREESAME (to an
2626  * empty tree). Better name suggestions?
2627  */
2628 static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
2629 {
2630         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2631         struct commit *unmarked = NULL, *marked = NULL;
2632         struct commit_list *p;
2633         unsigned n;
2634
2635         for (p = commit->parents, n = 0; p; p = p->next, n++) {
2636                 if (ts->treesame[n]) {
2637                         if (p->item->object.flags & TMP_MARK) {
2638                                 if (!marked)
2639                                         marked = p->item;
2640                         } else {
2641                                 if (!unmarked) {
2642                                         unmarked = p->item;
2643                                         break;
2644                                 }
2645                         }
2646                 }
2647         }
2648
2649         /*
2650          * If we are TREESAME to a marked-for-deletion parent, but not to any
2651          * unmarked parents, unmark the first TREESAME parent. This is the
2652          * parent that the default simplify_history==1 scan would have followed,
2653          * and it doesn't make sense to omit that path when asking for a
2654          * simplified full history. Retaining it improves the chances of
2655          * understanding odd missed merges that took an old version of a file.
2656          *
2657          * Example:
2658          *
2659          *   I--------*X       A modified the file, but mainline merge X used
2660          *    \       /        "-s ours", so took the version from I. X is
2661          *     `-*A--'         TREESAME to I and !TREESAME to A.
2662          *
2663          * Default log from X would produce "I". Without this check,
2664          * --full-history --simplify-merges would produce "I-A-X", showing
2665          * the merge commit X and that it changed A, but not making clear that
2666          * it had just taken the I version. With this check, the topology above
2667          * is retained.
2668          *
2669          * Note that it is possible that the simplification chooses a different
2670          * TREESAME parent from the default, in which case this test doesn't
2671          * activate, and we _do_ drop the default parent. Example:
2672          *
2673          *   I------X         A modified the file, but it was reverted in B,
2674          *    \    /          meaning mainline merge X is TREESAME to both
2675          *    *A-*B           parents.
2676          *
2677          * Default log would produce "I" by following the first parent;
2678          * --full-history --simplify-merges will produce "I-A-B". But this is a
2679          * reasonable result - it presents a logical full history leading from
2680          * I to X, and X is not an important merge.
2681          */
2682         if (!unmarked && marked) {
2683                 marked->object.flags &= ~TMP_MARK;
2684                 return 1;
2685         }
2686
2687         return 0;
2688 }
2689
2690 static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
2691 {
2692         struct commit_list **pp, *p;
2693         int nth_parent, removed = 0;
2694
2695         pp = &commit->parents;
2696         nth_parent = 0;
2697         while ((p = *pp) != NULL) {
2698                 struct commit *parent = p->item;
2699                 if (parent->object.flags & TMP_MARK) {
2700                         parent->object.flags &= ~TMP_MARK;
2701                         *pp = p->next;
2702                         free(p);
2703                         removed++;
2704                         compact_treesame(revs, commit, nth_parent);
2705                         continue;
2706                 }
2707                 pp = &p->next;
2708                 nth_parent++;
2709         }
2710
2711         /* Removing parents can only increase TREESAMEness */
2712         if (removed && !(commit->object.flags & TREESAME))
2713                 update_treesame(revs, commit);
2714
2715         return nth_parent;
2716 }
2717
2718 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
2719 {
2720         struct commit_list *p;
2721         struct commit *parent;
2722         struct merge_simplify_state *st, *pst;
2723         int cnt;
2724
2725         st = locate_simplify_state(revs, commit);
2726
2727         /*
2728          * Have we handled this one?
2729          */
2730         if (st->simplified)
2731                 return tail;
2732
2733         /*
2734          * An UNINTERESTING commit simplifies to itself, so does a
2735          * root commit.  We do not rewrite parents of such commit
2736          * anyway.
2737          */
2738         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
2739                 st->simplified = commit;
2740                 return tail;
2741         }
2742
2743         /*
2744          * Do we know what commit all of our parents that matter
2745          * should be rewritten to?  Otherwise we are not ready to
2746          * rewrite this one yet.
2747          */
2748         for (cnt = 0, p = commit->parents; p; p = p->next) {
2749                 pst = locate_simplify_state(revs, p->item);
2750                 if (!pst->simplified) {
2751                         tail = &commit_list_insert(p->item, tail)->next;
2752                         cnt++;
2753                 }
2754                 if (revs->first_parent_only)
2755                         break;
2756         }
2757         if (cnt) {
2758                 tail = &commit_list_insert(commit, tail)->next;
2759                 return tail;
2760         }
2761
2762         /*
2763          * Rewrite our list of parents. Note that this cannot
2764          * affect our TREESAME flags in any way - a commit is
2765          * always TREESAME to its simplification.
2766          */
2767         for (p = commit->parents; p; p = p->next) {
2768                 pst = locate_simplify_state(revs, p->item);
2769                 p->item = pst->simplified;
2770                 if (revs->first_parent_only)
2771                         break;
2772         }
2773
2774         if (revs->first_parent_only)
2775                 cnt = 1;
2776         else
2777                 cnt = remove_duplicate_parents(revs, commit);
2778
2779         /*
2780          * It is possible that we are a merge and one side branch
2781          * does not have any commit that touches the given paths;
2782          * in such a case, the immediate parent from that branch
2783          * will be rewritten to be the merge base.
2784          *
2785          *      o----X          X: the commit we are looking at;
2786          *     /    /           o: a commit that touches the paths;
2787          * ---o----'
2788          *
2789          * Further, a merge of an independent branch that doesn't
2790          * touch the path will reduce to a treesame root parent:
2791          *
2792          *  ----o----X          X: the commit we are looking at;
2793          *          /           o: a commit that touches the paths;
2794          *         r            r: a root commit not touching the paths
2795          *
2796          * Detect and simplify both cases.
2797          */
2798         if (1 < cnt) {
2799                 int marked = mark_redundant_parents(revs, commit);
2800                 marked += mark_treesame_root_parents(revs, commit);
2801                 if (marked)
2802                         marked -= leave_one_treesame_to_parent(revs, commit);
2803                 if (marked)
2804                         cnt = remove_marked_parents(revs, commit);
2805         }
2806
2807         /*
2808          * A commit simplifies to itself if it is a root, if it is
2809          * UNINTERESTING, if it touches the given paths, or if it is a
2810          * merge and its parents don't simplify to one relevant commit
2811          * (the first two cases are already handled at the beginning of
2812          * this function).
2813          *
2814          * Otherwise, it simplifies to what its sole relevant parent
2815          * simplifies to.
2816          */
2817         if (!cnt ||
2818             (commit->object.flags & UNINTERESTING) ||
2819             !(commit->object.flags & TREESAME) ||
2820             (parent = one_relevant_parent(revs, commit->parents)) == NULL)
2821                 st->simplified = commit;
2822         else {
2823                 pst = locate_simplify_state(revs, parent);
2824                 st->simplified = pst->simplified;
2825         }
2826         return tail;
2827 }
2828
2829 static void simplify_merges(struct rev_info *revs)
2830 {
2831         struct commit_list *list, *next;
2832         struct commit_list *yet_to_do, **tail;
2833         struct commit *commit;
2834
2835         if (!revs->prune)
2836                 return;
2837
2838         /* feed the list reversed */
2839         yet_to_do = NULL;
2840         for (list = revs->commits; list; list = next) {
2841                 commit = list->item;
2842                 next = list->next;
2843                 /*
2844                  * Do not free(list) here yet; the original list
2845                  * is used later in this function.
2846                  */
2847                 commit_list_insert(commit, &yet_to_do);
2848         }
2849         while (yet_to_do) {
2850                 list = yet_to_do;
2851                 yet_to_do = NULL;
2852                 tail = &yet_to_do;
2853                 while (list) {
2854                         commit = pop_commit(&list);
2855                         tail = simplify_one(revs, commit, tail);
2856                 }
2857         }
2858
2859         /* clean up the result, removing the simplified ones */
2860         list = revs->commits;
2861         revs->commits = NULL;
2862         tail = &revs->commits;
2863         while (list) {
2864                 struct merge_simplify_state *st;
2865
2866                 commit = pop_commit(&list);
2867                 st = locate_simplify_state(revs, commit);
2868                 if (st->simplified == commit)
2869                         tail = &commit_list_insert(commit, tail)->next;
2870         }
2871 }
2872
2873 static void set_children(struct rev_info *revs)
2874 {
2875         struct commit_list *l;
2876         for (l = revs->commits; l; l = l->next) {
2877                 struct commit *commit = l->item;
2878                 struct commit_list *p;
2879
2880                 for (p = commit->parents; p; p = p->next)
2881                         add_child(revs, p->item, commit);
2882         }
2883 }
2884
2885 void reset_revision_walk(void)
2886 {
2887         clear_object_flags(SEEN | ADDED | SHOWN);
2888 }
2889
2890 static int mark_uninteresting(const struct object_id *oid,
2891                               struct packed_git *pack,
2892                               uint32_t pos,
2893                               void *cb)
2894 {
2895         struct rev_info *revs = cb;
2896         struct object *o = parse_object(revs->repo, oid);
2897         o->flags |= UNINTERESTING | SEEN;
2898         return 0;
2899 }
2900
2901 int prepare_revision_walk(struct rev_info *revs)
2902 {
2903         int i;
2904         struct object_array old_pending;
2905         struct commit_list **next = &revs->commits;
2906
2907         memcpy(&old_pending, &revs->pending, sizeof(old_pending));
2908         revs->pending.nr = 0;
2909         revs->pending.alloc = 0;
2910         revs->pending.objects = NULL;
2911         for (i = 0; i < old_pending.nr; i++) {
2912                 struct object_array_entry *e = old_pending.objects + i;
2913                 struct commit *commit = handle_commit(revs, e);
2914                 if (commit) {
2915                         if (!(commit->object.flags & SEEN)) {
2916                                 commit->object.flags |= SEEN;
2917                                 next = commit_list_append(commit, next);
2918                         }
2919                 }
2920         }
2921         object_array_clear(&old_pending);
2922
2923         /* Signal whether we need per-parent treesame decoration */
2924         if (revs->simplify_merges ||
2925             (revs->limited && limiting_can_increase_treesame(revs)))
2926                 revs->treesame.name = "treesame";
2927
2928         if (revs->exclude_promisor_objects) {
2929                 for_each_packed_object(mark_uninteresting, revs,
2930                                        FOR_EACH_OBJECT_PROMISOR_ONLY);
2931         }
2932
2933         if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
2934                 commit_list_sort_by_date(&revs->commits);
2935         if (revs->no_walk)
2936                 return 0;
2937         if (revs->limited)
2938                 if (limit_list(revs) < 0)
2939                         return -1;
2940         if (revs->topo_order)
2941                 sort_in_topological_order(&revs->commits, revs->sort_order);
2942         if (revs->line_level_traverse)
2943                 line_log_filter(revs);
2944         if (revs->simplify_merges)
2945                 simplify_merges(revs);
2946         if (revs->children.name)
2947                 set_children(revs);
2948         return 0;
2949 }
2950
2951 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
2952 {
2953         struct commit_list *cache = NULL;
2954
2955         for (;;) {
2956                 struct commit *p = *pp;
2957                 if (!revs->limited)
2958                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
2959                                 return rewrite_one_error;
2960                 if (p->object.flags & UNINTERESTING)
2961                         return rewrite_one_ok;
2962                 if (!(p->object.flags & TREESAME))
2963                         return rewrite_one_ok;
2964                 if (!p->parents)
2965                         return rewrite_one_noparents;
2966                 if ((p = one_relevant_parent(revs, p->parents)) == NULL)
2967                         return rewrite_one_ok;
2968                 *pp = p;
2969         }
2970 }
2971
2972 int rewrite_parents(struct rev_info *revs, struct commit *commit,
2973         rewrite_parent_fn_t rewrite_parent)
2974 {
2975         struct commit_list **pp = &commit->parents;
2976         while (*pp) {
2977                 struct commit_list *parent = *pp;
2978                 switch (rewrite_parent(revs, &parent->item)) {
2979                 case rewrite_one_ok:
2980                         break;
2981                 case rewrite_one_noparents:
2982                         *pp = parent->next;
2983                         continue;
2984                 case rewrite_one_error:
2985                         return -1;
2986                 }
2987                 pp = &parent->next;
2988         }
2989         remove_duplicate_parents(revs, commit);
2990         return 0;
2991 }
2992
2993 static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
2994 {
2995         char *person, *endp;
2996         size_t len, namelen, maillen;
2997         const char *name;
2998         const char *mail;
2999         struct ident_split ident;
3000
3001         person = strstr(buf->buf, what);
3002         if (!person)
3003                 return 0;
3004
3005         person += strlen(what);
3006         endp = strchr(person, '\n');
3007         if (!endp)
3008                 return 0;
3009
3010         len = endp - person;
3011
3012         if (split_ident_line(&ident, person, len))
3013                 return 0;
3014
3015         mail = ident.mail_begin;
3016         maillen = ident.mail_end - ident.mail_begin;
3017         name = ident.name_begin;
3018         namelen = ident.name_end - ident.name_begin;
3019
3020         if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
3021                 struct strbuf namemail = STRBUF_INIT;
3022
3023                 strbuf_addf(&namemail, "%.*s <%.*s>",
3024                             (int)namelen, name, (int)maillen, mail);
3025
3026                 strbuf_splice(buf, ident.name_begin - buf->buf,
3027                               ident.mail_end - ident.name_begin + 1,
3028                               namemail.buf, namemail.len);
3029
3030                 strbuf_release(&namemail);
3031
3032                 return 1;
3033         }
3034
3035         return 0;
3036 }
3037
3038 static int commit_match(struct commit *commit, struct rev_info *opt)
3039 {
3040         int retval;
3041         const char *encoding;
3042         const char *message;
3043         struct strbuf buf = STRBUF_INIT;
3044
3045         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
3046                 return 1;
3047
3048         /* Prepend "fake" headers as needed */
3049         if (opt->grep_filter.use_reflog_filter) {
3050                 strbuf_addstr(&buf, "reflog ");
3051                 get_reflog_message(&buf, opt->reflog_info);
3052                 strbuf_addch(&buf, '\n');
3053         }
3054
3055         /*
3056          * We grep in the user's output encoding, under the assumption that it
3057          * is the encoding they are most likely to write their grep pattern
3058          * for. In addition, it means we will match the "notes" encoding below,
3059          * so we will not end up with a buffer that has two different encodings
3060          * in it.
3061          */
3062         encoding = get_log_output_encoding();
3063         message = logmsg_reencode(commit, NULL, encoding);
3064
3065         /* Copy the commit to temporary if we are using "fake" headers */
3066         if (buf.len)
3067                 strbuf_addstr(&buf, message);
3068
3069         if (opt->grep_filter.header_list && opt->mailmap) {
3070                 if (!buf.len)
3071                         strbuf_addstr(&buf, message);
3072
3073                 commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
3074                 commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
3075         }
3076
3077         /* Append "fake" message parts as needed */
3078         if (opt->show_notes) {
3079                 if (!buf.len)
3080                         strbuf_addstr(&buf, message);
3081                 format_display_notes(&commit->object.oid, &buf, encoding, 1);
3082         }
3083
3084         /*
3085          * Find either in the original commit message, or in the temporary.
3086          * Note that we cast away the constness of "message" here. It is
3087          * const because it may come from the cached commit buffer. That's OK,
3088          * because we know that it is modifiable heap memory, and that while
3089          * grep_buffer may modify it for speed, it will restore any
3090          * changes before returning.
3091          */
3092         if (buf.len)
3093                 retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
3094         else
3095                 retval = grep_buffer(&opt->grep_filter,
3096                                      (char *)message, strlen(message));
3097         strbuf_release(&buf);
3098         unuse_commit_buffer(commit, message);
3099         return opt->invert_grep ? !retval : retval;
3100 }
3101
3102 static inline int want_ancestry(const struct rev_info *revs)
3103 {
3104         return (revs->rewrite_parents || revs->children.name);
3105 }
3106
3107 /*
3108  * Return a timestamp to be used for --since/--until comparisons for this
3109  * commit, based on the revision options.
3110  */
3111 static timestamp_t comparison_date(const struct rev_info *revs,
3112                                    struct commit *commit)
3113 {
3114         return revs->reflog_info ?
3115                 get_reflog_timestamp(revs->reflog_info) :
3116                 commit->date;
3117 }
3118
3119 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
3120 {
3121         if (commit->object.flags & SHOWN)
3122                 return commit_ignore;
3123         if (revs->unpacked && has_object_pack(&commit->object.oid))
3124                 return commit_ignore;
3125         if (commit->object.flags & UNINTERESTING)
3126                 return commit_ignore;
3127         if (revs->min_age != -1 &&
3128             comparison_date(revs, commit) > revs->min_age)
3129                         return commit_ignore;
3130         if (revs->min_parents || (revs->max_parents >= 0)) {
3131                 int n = commit_list_count(commit->parents);
3132                 if ((n < revs->min_parents) ||
3133                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
3134                         return commit_ignore;
3135         }
3136         if (!commit_match(commit, revs))
3137                 return commit_ignore;
3138         if (revs->prune && revs->dense) {
3139                 /* Commit without changes? */
3140                 if (commit->object.flags & TREESAME) {
3141                         int n;
3142                         struct commit_list *p;
3143                         /* drop merges unless we want parenthood */
3144                         if (!want_ancestry(revs))
3145                                 return commit_ignore;
3146                         /*
3147                          * If we want ancestry, then need to keep any merges
3148                          * between relevant commits to tie together topology.
3149                          * For consistency with TREESAME and simplification
3150                          * use "relevant" here rather than just INTERESTING,
3151                          * to treat bottom commit(s) as part of the topology.
3152                          */
3153                         for (n = 0, p = commit->parents; p; p = p->next)
3154                                 if (relevant_commit(p->item))
3155                                         if (++n >= 2)
3156                                                 return commit_show;
3157                         return commit_ignore;
3158                 }
3159         }
3160         return commit_show;
3161 }
3162
3163 define_commit_slab(saved_parents, struct commit_list *);
3164
3165 #define EMPTY_PARENT_LIST ((struct commit_list *)-1)
3166
3167 /*
3168  * You may only call save_parents() once per commit (this is checked
3169  * for non-root commits).
3170  */
3171 static void save_parents(struct rev_info *revs, struct commit *commit)
3172 {
3173         struct commit_list **pp;
3174
3175         if (!revs->saved_parents_slab) {
3176                 revs->saved_parents_slab = xmalloc(sizeof(struct saved_parents));
3177                 init_saved_parents(revs->saved_parents_slab);
3178         }
3179
3180         pp = saved_parents_at(revs->saved_parents_slab, commit);
3181
3182         /*
3183          * When walking with reflogs, we may visit the same commit
3184          * several times: once for each appearance in the reflog.
3185          *
3186          * In this case, save_parents() will be called multiple times.
3187          * We want to keep only the first set of parents.  We need to
3188          * store a sentinel value for an empty (i.e., NULL) parent
3189          * list to distinguish it from a not-yet-saved list, however.
3190          */
3191         if (*pp)
3192                 return;
3193         if (commit->parents)
3194                 *pp = copy_commit_list(commit->parents);
3195         else
3196                 *pp = EMPTY_PARENT_LIST;
3197 }
3198
3199 static void free_saved_parents(struct rev_info *revs)
3200 {
3201         if (revs->saved_parents_slab)
3202                 clear_saved_parents(revs->saved_parents_slab);
3203 }
3204
3205 struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit)
3206 {
3207         struct commit_list *parents;
3208
3209         if (!revs->saved_parents_slab)
3210                 return commit->parents;
3211
3212         parents = *saved_parents_at(revs->saved_parents_slab, commit);
3213         if (parents == EMPTY_PARENT_LIST)
3214                 return NULL;
3215         return parents;
3216 }
3217
3218 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
3219 {
3220         enum commit_action action = get_commit_action(revs, commit);
3221
3222         if (action == commit_show &&
3223             revs->prune && revs->dense && want_ancestry(revs)) {
3224                 /*
3225                  * --full-diff on simplified parents is no good: it
3226                  * will show spurious changes from the commits that
3227                  * were elided.  So we save the parents on the side
3228                  * when --full-diff is in effect.
3229                  */
3230                 if (revs->full_diff)
3231                         save_parents(revs, commit);
3232                 if (rewrite_parents(revs, commit, rewrite_one) < 0)
3233                         return commit_error;
3234         }
3235         return action;
3236 }
3237
3238 static void track_linear(struct rev_info *revs, struct commit *commit)
3239 {
3240         if (revs->track_first_time) {
3241                 revs->linear = 1;
3242                 revs->track_first_time = 0;
3243         } else {
3244                 struct commit_list *p;
3245                 for (p = revs->previous_parents; p; p = p->next)
3246                         if (p->item == NULL || /* first commit */
3247                             oideq(&p->item->object.oid, &commit->object.oid))
3248                                 break;
3249                 revs->linear = p != NULL;
3250         }
3251         if (revs->reverse) {
3252                 if (revs->linear)
3253                         commit->object.flags |= TRACK_LINEAR;
3254         }
3255         free_commit_list(revs->previous_parents);
3256         revs->previous_parents = copy_commit_list(commit->parents);
3257 }
3258
3259 static struct commit *get_revision_1(struct rev_info *revs)
3260 {
3261         while (1) {
3262                 struct commit *commit;
3263
3264                 if (revs->reflog_info)
3265                         commit = next_reflog_entry(revs->reflog_info);
3266                 else
3267                         commit = pop_commit(&revs->commits);
3268
3269                 if (!commit)
3270                         return NULL;
3271
3272                 if (revs->reflog_info)
3273                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
3274
3275                 /*
3276                  * If we haven't done the list limiting, we need to look at
3277                  * the parents here. We also need to do the date-based limiting
3278                  * that we'd otherwise have done in limit_list().
3279                  */
3280                 if (!revs->limited) {
3281                         if (revs->max_age != -1 &&
3282                             comparison_date(revs, commit) < revs->max_age)
3283                                 continue;
3284
3285                         if (revs->reflog_info)
3286                                 try_to_simplify_commit(revs, commit);
3287                         else if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0) {
3288                                 if (!revs->ignore_missing_links)
3289                                         die("Failed to traverse parents of commit %s",
3290                                                 oid_to_hex(&commit->object.oid));
3291                         }
3292                 }
3293
3294                 switch (simplify_commit(revs, commit)) {
3295                 case commit_ignore:
3296                         continue;
3297                 case commit_error:
3298                         die("Failed to simplify parents of commit %s",
3299                             oid_to_hex(&commit->object.oid));
3300                 default:
3301                         if (revs->track_linear)
3302                                 track_linear(revs, commit);
3303                         return commit;
3304                 }
3305         }
3306 }
3307
3308 /*
3309  * Return true for entries that have not yet been shown.  (This is an
3310  * object_array_each_func_t.)
3311  */
3312 static int entry_unshown(struct object_array_entry *entry, void *cb_data_unused)
3313 {
3314         return !(entry->item->flags & SHOWN);
3315 }
3316
3317 /*
3318  * If array is on the verge of a realloc, garbage-collect any entries
3319  * that have already been shown to try to free up some space.
3320  */
3321 static void gc_boundary(struct object_array *array)
3322 {
3323         if (array->nr == array->alloc)
3324                 object_array_filter(array, entry_unshown, NULL);
3325 }
3326
3327 static void create_boundary_commit_list(struct rev_info *revs)
3328 {
3329         unsigned i;
3330         struct commit *c;
3331         struct object_array *array = &revs->boundary_commits;
3332         struct object_array_entry *objects = array->objects;
3333
3334         /*
3335          * If revs->commits is non-NULL at this point, an error occurred in
3336          * get_revision_1().  Ignore the error and continue printing the
3337          * boundary commits anyway.  (This is what the code has always
3338          * done.)
3339          */
3340         if (revs->commits) {
3341                 free_commit_list(revs->commits);
3342                 revs->commits = NULL;
3343         }
3344
3345         /*
3346          * Put all of the actual boundary commits from revs->boundary_commits
3347          * into revs->commits
3348          */
3349         for (i = 0; i < array->nr; i++) {
3350                 c = (struct commit *)(objects[i].item);
3351                 if (!c)
3352                         continue;
3353                 if (!(c->object.flags & CHILD_SHOWN))
3354                         continue;
3355                 if (c->object.flags & (SHOWN | BOUNDARY))
3356                         continue;
3357                 c->object.flags |= BOUNDARY;
3358                 commit_list_insert(c, &revs->commits);
3359         }
3360
3361         /*
3362          * If revs->topo_order is set, sort the boundary commits
3363          * in topological order
3364          */
3365         sort_in_topological_order(&revs->commits, revs->sort_order);
3366 }
3367
3368 static struct commit *get_revision_internal(struct rev_info *revs)
3369 {
3370         struct commit *c = NULL;
3371         struct commit_list *l;
3372
3373         if (revs->boundary == 2) {
3374                 /*
3375                  * All of the normal commits have already been returned,
3376                  * and we are now returning boundary commits.
3377                  * create_boundary_commit_list() has populated
3378                  * revs->commits with the remaining commits to return.
3379                  */
3380                 c = pop_commit(&revs->commits);
3381                 if (c)
3382                         c->object.flags |= SHOWN;
3383                 return c;
3384         }
3385
3386         /*
3387          * If our max_count counter has reached zero, then we are done. We
3388          * don't simply return NULL because we still might need to show
3389          * boundary commits. But we want to avoid calling get_revision_1, which
3390          * might do a considerable amount of work finding the next commit only
3391          * for us to throw it away.
3392          *
3393          * If it is non-zero, then either we don't have a max_count at all
3394          * (-1), or it is still counting, in which case we decrement.
3395          */
3396         if (revs->max_count) {
3397                 c = get_revision_1(revs);
3398                 if (c) {
3399                         while (revs->skip_count > 0) {
3400                                 revs->skip_count--;
3401                                 c = get_revision_1(revs);
3402                                 if (!c)
3403                                         break;
3404                         }
3405                 }
3406
3407                 if (revs->max_count > 0)
3408                         revs->max_count--;
3409         }
3410
3411         if (c)
3412                 c->object.flags |= SHOWN;
3413
3414         if (!revs->boundary)
3415                 return c;
3416
3417         if (!c) {
3418                 /*
3419                  * get_revision_1() runs out the commits, and
3420                  * we are done computing the boundaries.
3421                  * switch to boundary commits output mode.
3422                  */
3423                 revs->boundary = 2;
3424
3425                 /*
3426                  * Update revs->commits to contain the list of
3427                  * boundary commits.
3428                  */
3429                 create_boundary_commit_list(revs);
3430
3431                 return get_revision_internal(revs);
3432         }
3433
3434         /*
3435          * boundary commits are the commits that are parents of the
3436          * ones we got from get_revision_1() but they themselves are
3437          * not returned from get_revision_1().  Before returning
3438          * 'c', we need to mark its parents that they could be boundaries.
3439          */
3440
3441         for (l = c->parents; l; l = l->next) {
3442                 struct object *p;
3443                 p = &(l->item->object);
3444                 if (p->flags & (CHILD_SHOWN | SHOWN))
3445                         continue;
3446                 p->flags |= CHILD_SHOWN;
3447                 gc_boundary(&revs->boundary_commits);
3448                 add_object_array(p, NULL, &revs->boundary_commits);
3449         }
3450
3451         return c;
3452 }
3453
3454 struct commit *get_revision(struct rev_info *revs)
3455 {
3456         struct commit *c;
3457         struct commit_list *reversed;
3458
3459         if (revs->reverse) {
3460                 reversed = NULL;
3461                 while ((c = get_revision_internal(revs)))
3462                         commit_list_insert(c, &reversed);
3463                 revs->commits = reversed;
3464                 revs->reverse = 0;
3465                 revs->reverse_output_stage = 1;
3466         }
3467
3468         if (revs->reverse_output_stage) {
3469                 c = pop_commit(&revs->commits);
3470                 if (revs->track_linear)
3471                         revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
3472                 return c;
3473         }
3474
3475         c = get_revision_internal(revs);
3476         if (c && revs->graph)
3477                 graph_update(revs->graph, c);
3478         if (!c) {
3479                 free_saved_parents(revs);
3480                 if (revs->previous_parents) {
3481                         free_commit_list(revs->previous_parents);
3482                         revs->previous_parents = NULL;
3483                 }
3484         }
3485         return c;
3486 }
3487
3488 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
3489 {
3490         if (commit->object.flags & BOUNDARY)
3491                 return "-";
3492         else if (commit->object.flags & UNINTERESTING)
3493                 return "^";
3494         else if (commit->object.flags & PATCHSAME)
3495                 return "=";
3496         else if (!revs || revs->left_right) {
3497                 if (commit->object.flags & SYMMETRIC_LEFT)
3498                         return "<";
3499                 else
3500                         return ">";
3501         } else if (revs->graph)
3502                 return "*";
3503         else if (revs->cherry_mark)
3504                 return "+";
3505         return "";
3506 }
3507
3508 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
3509 {
3510         char *mark = get_revision_mark(revs, commit);
3511         if (!strlen(mark))
3512                 return;
3513         fputs(mark, stdout);
3514         putchar(' ');
3515 }