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