Merge branch 'nd/split-index-null-base-fix'
[git] / revision.c
1 #include "cache.h"
2 #include "object-store.h"
3 #include "tag.h"
4 #include "blob.h"
5 #include "tree.h"
6 #include "commit.h"
7 #include "diff.h"
8 #include "refs.h"
9 #include "revision.h"
10 #include "repository.h"
11 #include "graph.h"
12 #include "grep.h"
13 #include "reflog-walk.h"
14 #include "patch-ids.h"
15 #include "decorate.h"
16 #include "log-tree.h"
17 #include "string-list.h"
18 #include "line-log.h"
19 #include "mailmap.h"
20 #include "commit-slab.h"
21 #include "dir.h"
22 #include "cache-tree.h"
23 #include "bisect.h"
24 #include "packfile.h"
25 #include "worktree.h"
26 #include "argv-array.h"
27 #include "commit-reach.h"
28 #include "commit-graph.h"
29 #include "prio-queue.h"
30 #include "hashmap.h"
31
32 volatile show_early_output_fn_t show_early_output;
33
34 static const char *term_bad;
35 static const char *term_good;
36
37 implement_shared_commit_slab(revision_sources, char *);
38
39 void show_object_with_name(FILE *out, struct object *obj, const char *name)
40 {
41         const char *p;
42
43         fprintf(out, "%s ", oid_to_hex(&obj->oid));
44         for (p = name; *p && *p != '\n'; p++)
45                 fputc(*p, out);
46         fputc('\n', out);
47 }
48
49 static void mark_blob_uninteresting(struct blob *blob)
50 {
51         if (!blob)
52                 return;
53         if (blob->object.flags & UNINTERESTING)
54                 return;
55         blob->object.flags |= UNINTERESTING;
56 }
57
58 static void mark_tree_contents_uninteresting(struct repository *r,
59                                              struct tree *tree)
60 {
61         struct tree_desc desc;
62         struct name_entry entry;
63
64         if (parse_tree_gently(tree, 1) < 0)
65                 return;
66
67         init_tree_desc(&desc, tree->buffer, tree->size);
68         while (tree_entry(&desc, &entry)) {
69                 switch (object_type(entry.mode)) {
70                 case OBJ_TREE:
71                         mark_tree_uninteresting(r, lookup_tree(r, &entry.oid));
72                         break;
73                 case OBJ_BLOB:
74                         mark_blob_uninteresting(lookup_blob(r, &entry.oid));
75                         break;
76                 default:
77                         /* Subproject commit - not in this repository */
78                         break;
79                 }
80         }
81
82         /*
83          * We don't care about the tree any more
84          * after it has been marked uninteresting.
85          */
86         free_tree_buffer(tree);
87 }
88
89 void mark_tree_uninteresting(struct repository *r, struct tree *tree)
90 {
91         struct object *obj;
92
93         if (!tree)
94                 return;
95
96         obj = &tree->object;
97         if (obj->flags & UNINTERESTING)
98                 return;
99         obj->flags |= UNINTERESTING;
100         mark_tree_contents_uninteresting(r, tree);
101 }
102
103 struct path_and_oids_entry {
104         struct hashmap_entry ent;
105         char *path;
106         struct oidset trees;
107 };
108
109 static int path_and_oids_cmp(const void *hashmap_cmp_fn_data,
110                              const struct path_and_oids_entry *e1,
111                              const struct path_and_oids_entry *e2,
112                              const void *keydata)
113 {
114         return strcmp(e1->path, e2->path);
115 }
116
117 static void paths_and_oids_init(struct hashmap *map)
118 {
119         hashmap_init(map, (hashmap_cmp_fn) path_and_oids_cmp, NULL, 0);
120 }
121
122 static void paths_and_oids_clear(struct hashmap *map)
123 {
124         struct hashmap_iter iter;
125         struct path_and_oids_entry *entry;
126         hashmap_iter_init(map, &iter);
127
128         while ((entry = (struct path_and_oids_entry *)hashmap_iter_next(&iter))) {
129                 oidset_clear(&entry->trees);
130                 free(entry->path);
131         }
132
133         hashmap_free(map, 1);
134 }
135
136 static void paths_and_oids_insert(struct hashmap *map,
137                                   const char *path,
138                                   const struct object_id *oid)
139 {
140         int hash = strhash(path);
141         struct path_and_oids_entry key;
142         struct path_and_oids_entry *entry;
143
144         hashmap_entry_init(&key, hash);
145
146         /* use a shallow copy for the lookup */
147         key.path = (char *)path;
148         oidset_init(&key.trees, 0);
149
150         if (!(entry = (struct path_and_oids_entry *)hashmap_get(map, &key, NULL))) {
151                 entry = xcalloc(1, sizeof(struct path_and_oids_entry));
152                 hashmap_entry_init(entry, hash);
153                 entry->path = xstrdup(key.path);
154                 oidset_init(&entry->trees, 16);
155                 hashmap_put(map, entry);
156         }
157
158         oidset_insert(&entry->trees, oid);
159 }
160
161 static void add_children_by_path(struct repository *r,
162                                  struct tree *tree,
163                                  struct hashmap *map)
164 {
165         struct tree_desc desc;
166         struct name_entry entry;
167
168         if (!tree)
169                 return;
170
171         if (parse_tree_gently(tree, 1) < 0)
172                 return;
173
174         init_tree_desc(&desc, tree->buffer, tree->size);
175         while (tree_entry(&desc, &entry)) {
176                 switch (object_type(entry.mode)) {
177                 case OBJ_TREE:
178                         paths_and_oids_insert(map, entry.path, &entry.oid);
179
180                         if (tree->object.flags & UNINTERESTING) {
181                                 struct tree *child = lookup_tree(r, &entry.oid);
182                                 if (child)
183                                         child->object.flags |= UNINTERESTING;
184                         }
185                         break;
186                 case OBJ_BLOB:
187                         if (tree->object.flags & UNINTERESTING) {
188                                 struct blob *child = lookup_blob(r, &entry.oid);
189                                 if (child)
190                                         child->object.flags |= UNINTERESTING;
191                         }
192                         break;
193                 default:
194                         /* Subproject commit - not in this repository */
195                         break;
196                 }
197         }
198
199         free_tree_buffer(tree);
200 }
201
202 void mark_trees_uninteresting_sparse(struct repository *r,
203                                      struct oidset *trees)
204 {
205         unsigned has_interesting = 0, has_uninteresting = 0;
206         struct hashmap map;
207         struct hashmap_iter map_iter;
208         struct path_and_oids_entry *entry;
209         struct object_id *oid;
210         struct oidset_iter iter;
211
212         oidset_iter_init(trees, &iter);
213         while ((!has_interesting || !has_uninteresting) &&
214                (oid = oidset_iter_next(&iter))) {
215                 struct tree *tree = lookup_tree(r, oid);
216
217                 if (!tree)
218                         continue;
219
220                 if (tree->object.flags & UNINTERESTING)
221                         has_uninteresting = 1;
222                 else
223                         has_interesting = 1;
224         }
225
226         /* Do not walk unless we have both types of trees. */
227         if (!has_uninteresting || !has_interesting)
228                 return;
229
230         paths_and_oids_init(&map);
231
232         oidset_iter_init(trees, &iter);
233         while ((oid = oidset_iter_next(&iter))) {
234                 struct tree *tree = lookup_tree(r, oid);
235                 add_children_by_path(r, tree, &map);
236         }
237
238         hashmap_iter_init(&map, &map_iter);
239         while ((entry = hashmap_iter_next(&map_iter)))
240                 mark_trees_uninteresting_sparse(r, &entry->trees);
241
242         paths_and_oids_clear(&map);
243 }
244
245 struct commit_stack {
246         struct commit **items;
247         size_t nr, alloc;
248 };
249 #define COMMIT_STACK_INIT { NULL, 0, 0 }
250
251 static void commit_stack_push(struct commit_stack *stack, struct commit *commit)
252 {
253         ALLOC_GROW(stack->items, stack->nr + 1, stack->alloc);
254         stack->items[stack->nr++] = commit;
255 }
256
257 static struct commit *commit_stack_pop(struct commit_stack *stack)
258 {
259         return stack->nr ? stack->items[--stack->nr] : NULL;
260 }
261
262 static void commit_stack_clear(struct commit_stack *stack)
263 {
264         FREE_AND_NULL(stack->items);
265         stack->nr = stack->alloc = 0;
266 }
267
268 static void mark_one_parent_uninteresting(struct commit *commit,
269                                           struct commit_stack *pending)
270 {
271         struct commit_list *l;
272
273         if (commit->object.flags & UNINTERESTING)
274                 return;
275         commit->object.flags |= UNINTERESTING;
276
277         /*
278          * Normally we haven't parsed the parent
279          * yet, so we won't have a parent of a parent
280          * here. However, it may turn out that we've
281          * reached this commit some other way (where it
282          * wasn't uninteresting), in which case we need
283          * to mark its parents recursively too..
284          */
285         for (l = commit->parents; l; l = l->next)
286                 commit_stack_push(pending, l->item);
287 }
288
289 void mark_parents_uninteresting(struct commit *commit)
290 {
291         struct commit_stack pending = COMMIT_STACK_INIT;
292         struct commit_list *l;
293
294         for (l = commit->parents; l; l = l->next)
295                 mark_one_parent_uninteresting(l->item, &pending);
296
297         while (pending.nr > 0)
298                 mark_one_parent_uninteresting(commit_stack_pop(&pending),
299                                               &pending);
300
301         commit_stack_clear(&pending);
302 }
303
304 static void add_pending_object_with_path(struct rev_info *revs,
305                                          struct object *obj,
306                                          const char *name, unsigned mode,
307                                          const char *path)
308 {
309         if (!obj)
310                 return;
311         if (revs->no_walk && (obj->flags & UNINTERESTING))
312                 revs->no_walk = 0;
313         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
314                 struct strbuf buf = STRBUF_INIT;
315                 int len = interpret_branch_name(name, 0, &buf, 0);
316
317                 if (0 < len && name[len] && buf.len)
318                         strbuf_addstr(&buf, name + len);
319                 add_reflog_for_walk(revs->reflog_info,
320                                     (struct commit *)obj,
321                                     buf.buf[0] ? buf.buf: name);
322                 strbuf_release(&buf);
323                 return; /* do not add the commit itself */
324         }
325         add_object_array_with_path(obj, name, &revs->pending, mode, path);
326 }
327
328 static void add_pending_object_with_mode(struct rev_info *revs,
329                                          struct object *obj,
330                                          const char *name, unsigned mode)
331 {
332         add_pending_object_with_path(revs, obj, name, mode, NULL);
333 }
334
335 void add_pending_object(struct rev_info *revs,
336                         struct object *obj, const char *name)
337 {
338         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
339 }
340
341 void add_head_to_pending(struct rev_info *revs)
342 {
343         struct object_id oid;
344         struct object *obj;
345         if (get_oid("HEAD", &oid))
346                 return;
347         obj = parse_object(revs->repo, &oid);
348         if (!obj)
349                 return;
350         add_pending_object(revs, obj, "HEAD");
351 }
352
353 static struct object *get_reference(struct rev_info *revs, const char *name,
354                                     const struct object_id *oid,
355                                     unsigned int flags)
356 {
357         struct object *object;
358
359         /*
360          * If the repository has commit graphs, repo_parse_commit() avoids
361          * reading the object buffer, so use it whenever possible.
362          */
363         if (oid_object_info(revs->repo, oid, NULL) == OBJ_COMMIT) {
364                 struct commit *c = lookup_commit(revs->repo, oid);
365                 if (!repo_parse_commit(revs->repo, c))
366                         object = (struct object *) c;
367                 else
368                         object = NULL;
369         } else {
370                 object = parse_object(revs->repo, oid);
371         }
372
373         if (!object) {
374                 if (revs->ignore_missing)
375                         return object;
376                 if (revs->exclude_promisor_objects && is_promisor_object(oid))
377                         return NULL;
378                 die("bad object %s", name);
379         }
380         object->flags |= flags;
381         return object;
382 }
383
384 void add_pending_oid(struct rev_info *revs, const char *name,
385                       const struct object_id *oid, unsigned int flags)
386 {
387         struct object *object = get_reference(revs, name, oid, flags);
388         add_pending_object(revs, object, name);
389 }
390
391 static struct commit *handle_commit(struct rev_info *revs,
392                                     struct object_array_entry *entry)
393 {
394         struct object *object = entry->item;
395         const char *name = entry->name;
396         const char *path = entry->path;
397         unsigned int mode = entry->mode;
398         unsigned long flags = object->flags;
399
400         /*
401          * Tag object? Look what it points to..
402          */
403         while (object->type == OBJ_TAG) {
404                 struct tag *tag = (struct tag *) object;
405                 if (revs->tag_objects && !(flags & UNINTERESTING))
406                         add_pending_object(revs, object, tag->tag);
407                 if (!tag->tagged)
408                         die("bad tag");
409                 object = parse_object(revs->repo, &tag->tagged->oid);
410                 if (!object) {
411                         if (revs->ignore_missing_links || (flags & UNINTERESTING))
412                                 return NULL;
413                         if (revs->exclude_promisor_objects &&
414                             is_promisor_object(&tag->tagged->oid))
415                                 return NULL;
416                         die("bad object %s", oid_to_hex(&tag->tagged->oid));
417                 }
418                 object->flags |= flags;
419                 /*
420                  * We'll handle the tagged object by looping or dropping
421                  * through to the non-tag handlers below. Do not
422                  * propagate path data from the tag's pending entry.
423                  */
424                 path = NULL;
425                 mode = 0;
426         }
427
428         /*
429          * Commit object? Just return it, we'll do all the complex
430          * reachability crud.
431          */
432         if (object->type == OBJ_COMMIT) {
433                 struct commit *commit = (struct commit *)object;
434
435                 if (parse_commit(commit) < 0)
436                         die("unable to parse commit %s", name);
437                 if (flags & UNINTERESTING) {
438                         mark_parents_uninteresting(commit);
439                         revs->limited = 1;
440                 }
441                 if (revs->sources) {
442                         char **slot = revision_sources_at(revs->sources, commit);
443
444                         if (!*slot)
445                                 *slot = xstrdup(name);
446                 }
447                 return commit;
448         }
449
450         /*
451          * Tree object? Either mark it uninteresting, or add it
452          * to the list of objects to look at later..
453          */
454         if (object->type == OBJ_TREE) {
455                 struct tree *tree = (struct tree *)object;
456                 if (!revs->tree_objects)
457                         return NULL;
458                 if (flags & UNINTERESTING) {
459                         mark_tree_contents_uninteresting(revs->repo, tree);
460                         return NULL;
461                 }
462                 add_pending_object_with_path(revs, object, name, mode, path);
463                 return NULL;
464         }
465
466         /*
467          * Blob object? You know the drill by now..
468          */
469         if (object->type == OBJ_BLOB) {
470                 if (!revs->blob_objects)
471                         return NULL;
472                 if (flags & UNINTERESTING)
473                         return NULL;
474                 add_pending_object_with_path(revs, object, name, mode, path);
475                 return NULL;
476         }
477         die("%s is unknown object", name);
478 }
479
480 static int everybody_uninteresting(struct commit_list *orig,
481                                    struct commit **interesting_cache)
482 {
483         struct commit_list *list = orig;
484
485         if (*interesting_cache) {
486                 struct commit *commit = *interesting_cache;
487                 if (!(commit->object.flags & UNINTERESTING))
488                         return 0;
489         }
490
491         while (list) {
492                 struct commit *commit = list->item;
493                 list = list->next;
494                 if (commit->object.flags & UNINTERESTING)
495                         continue;
496
497                 *interesting_cache = commit;
498                 return 0;
499         }
500         return 1;
501 }
502
503 /*
504  * A definition of "relevant" commit that we can use to simplify limited graphs
505  * by eliminating side branches.
506  *
507  * A "relevant" commit is one that is !UNINTERESTING (ie we are including it
508  * in our list), or that is a specified BOTTOM commit. Then after computing
509  * a limited list, during processing we can generally ignore boundary merges
510  * coming from outside the graph, (ie from irrelevant parents), and treat
511  * those merges as if they were single-parent. TREESAME is defined to consider
512  * only relevant parents, if any. If we are TREESAME to our on-graph parents,
513  * we don't care if we were !TREESAME to non-graph parents.
514  *
515  * Treating bottom commits as relevant ensures that a limited graph's
516  * connection to the actual bottom commit is not viewed as a side branch, but
517  * treated as part of the graph. For example:
518  *
519  *   ....Z...A---X---o---o---B
520  *        .     /
521  *         W---Y
522  *
523  * When computing "A..B", the A-X connection is at least as important as
524  * Y-X, despite A being flagged UNINTERESTING.
525  *
526  * And when computing --ancestry-path "A..B", the A-X connection is more
527  * important than Y-X, despite both A and Y being flagged UNINTERESTING.
528  */
529 static inline int relevant_commit(struct commit *commit)
530 {
531         return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
532 }
533
534 /*
535  * Return a single relevant commit from a parent list. If we are a TREESAME
536  * commit, and this selects one of our parents, then we can safely simplify to
537  * that parent.
538  */
539 static struct commit *one_relevant_parent(const struct rev_info *revs,
540                                           struct commit_list *orig)
541 {
542         struct commit_list *list = orig;
543         struct commit *relevant = NULL;
544
545         if (!orig)
546                 return NULL;
547
548         /*
549          * For 1-parent commits, or if first-parent-only, then return that
550          * first parent (even if not "relevant" by the above definition).
551          * TREESAME will have been set purely on that parent.
552          */
553         if (revs->first_parent_only || !orig->next)
554                 return orig->item;
555
556         /*
557          * For multi-parent commits, identify a sole relevant parent, if any.
558          * If we have only one relevant parent, then TREESAME will be set purely
559          * with regard to that parent, and we can simplify accordingly.
560          *
561          * If we have more than one relevant parent, or no relevant parents
562          * (and multiple irrelevant ones), then we can't select a parent here
563          * and return NULL.
564          */
565         while (list) {
566                 struct commit *commit = list->item;
567                 list = list->next;
568                 if (relevant_commit(commit)) {
569                         if (relevant)
570                                 return NULL;
571                         relevant = commit;
572                 }
573         }
574         return relevant;
575 }
576
577 /*
578  * The goal is to get REV_TREE_NEW as the result only if the
579  * diff consists of all '+' (and no other changes), REV_TREE_OLD
580  * if the whole diff is removal of old data, and otherwise
581  * REV_TREE_DIFFERENT (of course if the trees are the same we
582  * want REV_TREE_SAME).
583  *
584  * The only time we care about the distinction is when
585  * remove_empty_trees is in effect, in which case we care only about
586  * whether the whole change is REV_TREE_NEW, or if there's another type
587  * of change. Which means we can stop the diff early in either of these
588  * cases:
589  *
590  *   1. We're not using remove_empty_trees at all.
591  *
592  *   2. We saw anything except REV_TREE_NEW.
593  */
594 static int tree_difference = REV_TREE_SAME;
595
596 static void file_add_remove(struct diff_options *options,
597                     int addremove, unsigned mode,
598                     const struct object_id *oid,
599                     int oid_valid,
600                     const char *fullpath, unsigned dirty_submodule)
601 {
602         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
603         struct rev_info *revs = options->change_fn_data;
604
605         tree_difference |= diff;
606         if (!revs->remove_empty_trees || tree_difference != REV_TREE_NEW)
607                 options->flags.has_changes = 1;
608 }
609
610 static void file_change(struct diff_options *options,
611                  unsigned old_mode, unsigned new_mode,
612                  const struct object_id *old_oid,
613                  const struct object_id *new_oid,
614                  int old_oid_valid, int new_oid_valid,
615                  const char *fullpath,
616                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
617 {
618         tree_difference = REV_TREE_DIFFERENT;
619         options->flags.has_changes = 1;
620 }
621
622 static int rev_compare_tree(struct rev_info *revs,
623                             struct commit *parent, struct commit *commit)
624 {
625         struct tree *t1 = get_commit_tree(parent);
626         struct tree *t2 = get_commit_tree(commit);
627
628         if (!t1)
629                 return REV_TREE_NEW;
630         if (!t2)
631                 return REV_TREE_OLD;
632
633         if (revs->simplify_by_decoration) {
634                 /*
635                  * If we are simplifying by decoration, then the commit
636                  * is worth showing if it has a tag pointing at it.
637                  */
638                 if (get_name_decoration(&commit->object))
639                         return REV_TREE_DIFFERENT;
640                 /*
641                  * A commit that is not pointed by a tag is uninteresting
642                  * if we are not limited by path.  This means that you will
643                  * see the usual "commits that touch the paths" plus any
644                  * tagged commit by specifying both --simplify-by-decoration
645                  * and pathspec.
646                  */
647                 if (!revs->prune_data.nr)
648                         return REV_TREE_SAME;
649         }
650
651         tree_difference = REV_TREE_SAME;
652         revs->pruning.flags.has_changes = 0;
653         if (diff_tree_oid(&t1->object.oid, &t2->object.oid, "",
654                            &revs->pruning) < 0)
655                 return REV_TREE_DIFFERENT;
656         return tree_difference;
657 }
658
659 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
660 {
661         int retval;
662         struct tree *t1 = get_commit_tree(commit);
663
664         if (!t1)
665                 return 0;
666
667         tree_difference = REV_TREE_SAME;
668         revs->pruning.flags.has_changes = 0;
669         retval = diff_tree_oid(NULL, &t1->object.oid, "", &revs->pruning);
670
671         return retval >= 0 && (tree_difference == REV_TREE_SAME);
672 }
673
674 struct treesame_state {
675         unsigned int nparents;
676         unsigned char treesame[FLEX_ARRAY];
677 };
678
679 static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
680 {
681         unsigned n = commit_list_count(commit->parents);
682         struct treesame_state *st = xcalloc(1, st_add(sizeof(*st), n));
683         st->nparents = n;
684         add_decoration(&revs->treesame, &commit->object, st);
685         return st;
686 }
687
688 /*
689  * Must be called immediately after removing the nth_parent from a commit's
690  * parent list, if we are maintaining the per-parent treesame[] decoration.
691  * This does not recalculate the master TREESAME flag - update_treesame()
692  * should be called to update it after a sequence of treesame[] modifications
693  * that may have affected it.
694  */
695 static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
696 {
697         struct treesame_state *st;
698         int old_same;
699
700         if (!commit->parents) {
701                 /*
702                  * Have just removed the only parent from a non-merge.
703                  * Different handling, as we lack decoration.
704                  */
705                 if (nth_parent != 0)
706                         die("compact_treesame %u", nth_parent);
707                 old_same = !!(commit->object.flags & TREESAME);
708                 if (rev_same_tree_as_empty(revs, commit))
709                         commit->object.flags |= TREESAME;
710                 else
711                         commit->object.flags &= ~TREESAME;
712                 return old_same;
713         }
714
715         st = lookup_decoration(&revs->treesame, &commit->object);
716         if (!st || nth_parent >= st->nparents)
717                 die("compact_treesame %u", nth_parent);
718
719         old_same = st->treesame[nth_parent];
720         memmove(st->treesame + nth_parent,
721                 st->treesame + nth_parent + 1,
722                 st->nparents - nth_parent - 1);
723
724         /*
725          * If we've just become a non-merge commit, update TREESAME
726          * immediately, and remove the no-longer-needed decoration.
727          * If still a merge, defer update until update_treesame().
728          */
729         if (--st->nparents == 1) {
730                 if (commit->parents->next)
731                         die("compact_treesame parents mismatch");
732                 if (st->treesame[0] && revs->dense)
733                         commit->object.flags |= TREESAME;
734                 else
735                         commit->object.flags &= ~TREESAME;
736                 free(add_decoration(&revs->treesame, &commit->object, NULL));
737         }
738
739         return old_same;
740 }
741
742 static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
743 {
744         if (commit->parents && commit->parents->next) {
745                 unsigned n;
746                 struct treesame_state *st;
747                 struct commit_list *p;
748                 unsigned relevant_parents;
749                 unsigned relevant_change, irrelevant_change;
750
751                 st = lookup_decoration(&revs->treesame, &commit->object);
752                 if (!st)
753                         die("update_treesame %s", oid_to_hex(&commit->object.oid));
754                 relevant_parents = 0;
755                 relevant_change = irrelevant_change = 0;
756                 for (p = commit->parents, n = 0; p; n++, p = p->next) {
757                         if (relevant_commit(p->item)) {
758                                 relevant_change |= !st->treesame[n];
759                                 relevant_parents++;
760                         } else
761                                 irrelevant_change |= !st->treesame[n];
762                 }
763                 if (relevant_parents ? relevant_change : irrelevant_change)
764                         commit->object.flags &= ~TREESAME;
765                 else
766                         commit->object.flags |= TREESAME;
767         }
768
769         return commit->object.flags & TREESAME;
770 }
771
772 static inline int limiting_can_increase_treesame(const struct rev_info *revs)
773 {
774         /*
775          * TREESAME is irrelevant unless prune && dense;
776          * if simplify_history is set, we can't have a mixture of TREESAME and
777          *    !TREESAME INTERESTING parents (and we don't have treesame[]
778          *    decoration anyway);
779          * if first_parent_only is set, then the TREESAME flag is locked
780          *    against the first parent (and again we lack treesame[] decoration).
781          */
782         return revs->prune && revs->dense &&
783                !revs->simplify_history &&
784                !revs->first_parent_only;
785 }
786
787 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
788 {
789         struct commit_list **pp, *parent;
790         struct treesame_state *ts = NULL;
791         int relevant_change = 0, irrelevant_change = 0;
792         int relevant_parents, nth_parent;
793
794         /*
795          * If we don't do pruning, everything is interesting
796          */
797         if (!revs->prune)
798                 return;
799
800         if (!get_commit_tree(commit))
801                 return;
802
803         if (!commit->parents) {
804                 if (rev_same_tree_as_empty(revs, commit))
805                         commit->object.flags |= TREESAME;
806                 return;
807         }
808
809         /*
810          * Normal non-merge commit? If we don't want to make the
811          * history dense, we consider it always to be a change..
812          */
813         if (!revs->dense && !commit->parents->next)
814                 return;
815
816         for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
817              (parent = *pp) != NULL;
818              pp = &parent->next, nth_parent++) {
819                 struct commit *p = parent->item;
820                 if (relevant_commit(p))
821                         relevant_parents++;
822
823                 if (nth_parent == 1) {
824                         /*
825                          * This our second loop iteration - so we now know
826                          * we're dealing with a merge.
827                          *
828                          * Do not compare with later parents when we care only about
829                          * the first parent chain, in order to avoid derailing the
830                          * traversal to follow a side branch that brought everything
831                          * in the path we are limited to by the pathspec.
832                          */
833                         if (revs->first_parent_only)
834                                 break;
835                         /*
836                          * If this will remain a potentially-simplifiable
837                          * merge, remember per-parent treesame if needed.
838                          * Initialise the array with the comparison from our
839                          * first iteration.
840                          */
841                         if (revs->treesame.name &&
842                             !revs->simplify_history &&
843                             !(commit->object.flags & UNINTERESTING)) {
844                                 ts = initialise_treesame(revs, commit);
845                                 if (!(irrelevant_change || relevant_change))
846                                         ts->treesame[0] = 1;
847                         }
848                 }
849                 if (parse_commit(p) < 0)
850                         die("cannot simplify commit %s (because of %s)",
851                             oid_to_hex(&commit->object.oid),
852                             oid_to_hex(&p->object.oid));
853                 switch (rev_compare_tree(revs, p, commit)) {
854                 case REV_TREE_SAME:
855                         if (!revs->simplify_history || !relevant_commit(p)) {
856                                 /* Even if a merge with an uninteresting
857                                  * side branch brought the entire change
858                                  * we are interested in, we do not want
859                                  * to lose the other branches of this
860                                  * merge, so we just keep going.
861                                  */
862                                 if (ts)
863                                         ts->treesame[nth_parent] = 1;
864                                 continue;
865                         }
866                         parent->next = NULL;
867                         commit->parents = parent;
868                         commit->object.flags |= TREESAME;
869                         return;
870
871                 case REV_TREE_NEW:
872                         if (revs->remove_empty_trees &&
873                             rev_same_tree_as_empty(revs, p)) {
874                                 /* We are adding all the specified
875                                  * paths from this parent, so the
876                                  * history beyond this parent is not
877                                  * interesting.  Remove its parents
878                                  * (they are grandparents for us).
879                                  * IOW, we pretend this parent is a
880                                  * "root" commit.
881                                  */
882                                 if (parse_commit(p) < 0)
883                                         die("cannot simplify commit %s (invalid %s)",
884                                             oid_to_hex(&commit->object.oid),
885                                             oid_to_hex(&p->object.oid));
886                                 p->parents = NULL;
887                         }
888                 /* fallthrough */
889                 case REV_TREE_OLD:
890                 case REV_TREE_DIFFERENT:
891                         if (relevant_commit(p))
892                                 relevant_change = 1;
893                         else
894                                 irrelevant_change = 1;
895                         continue;
896                 }
897                 die("bad tree compare for commit %s", oid_to_hex(&commit->object.oid));
898         }
899
900         /*
901          * TREESAME is straightforward for single-parent commits. For merge
902          * commits, it is most useful to define it so that "irrelevant"
903          * parents cannot make us !TREESAME - if we have any relevant
904          * parents, then we only consider TREESAMEness with respect to them,
905          * allowing irrelevant merges from uninteresting branches to be
906          * simplified away. Only if we have only irrelevant parents do we
907          * base TREESAME on them. Note that this logic is replicated in
908          * update_treesame, which should be kept in sync.
909          */
910         if (relevant_parents ? !relevant_change : !irrelevant_change)
911                 commit->object.flags |= TREESAME;
912 }
913
914 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
915                     struct commit_list *cached_base, struct commit_list **cache)
916 {
917         struct commit_list *new_entry;
918
919         if (cached_base && p->date < cached_base->item->date)
920                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
921         else
922                 new_entry = commit_list_insert_by_date(p, head);
923
924         if (cache && (!*cache || p->date < (*cache)->item->date))
925                 *cache = new_entry;
926 }
927
928 static int process_parents(struct rev_info *revs, struct commit *commit,
929                            struct commit_list **list, struct commit_list **cache_ptr)
930 {
931         struct commit_list *parent = commit->parents;
932         unsigned left_flag;
933         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
934
935         if (commit->object.flags & ADDED)
936                 return 0;
937         commit->object.flags |= ADDED;
938
939         if (revs->include_check &&
940             !revs->include_check(commit, revs->include_check_data))
941                 return 0;
942
943         /*
944          * If the commit is uninteresting, don't try to
945          * prune parents - we want the maximal uninteresting
946          * set.
947          *
948          * Normally we haven't parsed the parent
949          * yet, so we won't have a parent of a parent
950          * here. However, it may turn out that we've
951          * reached this commit some other way (where it
952          * wasn't uninteresting), in which case we need
953          * to mark its parents recursively too..
954          */
955         if (commit->object.flags & UNINTERESTING) {
956                 while (parent) {
957                         struct commit *p = parent->item;
958                         parent = parent->next;
959                         if (p)
960                                 p->object.flags |= UNINTERESTING;
961                         if (parse_commit_gently(p, 1) < 0)
962                                 continue;
963                         if (p->parents)
964                                 mark_parents_uninteresting(p);
965                         if (p->object.flags & SEEN)
966                                 continue;
967                         p->object.flags |= SEEN;
968                         if (list)
969                                 commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
970                 }
971                 return 0;
972         }
973
974         /*
975          * Ok, the commit wasn't uninteresting. Try to
976          * simplify the commit history and find the parent
977          * that has no differences in the path set if one exists.
978          */
979         try_to_simplify_commit(revs, commit);
980
981         if (revs->no_walk)
982                 return 0;
983
984         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
985
986         for (parent = commit->parents; parent; parent = parent->next) {
987                 struct commit *p = parent->item;
988                 int gently = revs->ignore_missing_links ||
989                              revs->exclude_promisor_objects;
990                 if (parse_commit_gently(p, gently) < 0) {
991                         if (revs->exclude_promisor_objects &&
992                             is_promisor_object(&p->object.oid)) {
993                                 if (revs->first_parent_only)
994                                         break;
995                                 continue;
996                         }
997                         return -1;
998                 }
999                 if (revs->sources) {
1000                         char **slot = revision_sources_at(revs->sources, p);
1001
1002                         if (!*slot)
1003                                 *slot = *revision_sources_at(revs->sources, commit);
1004                 }
1005                 p->object.flags |= left_flag;
1006                 if (!(p->object.flags & SEEN)) {
1007                         p->object.flags |= SEEN;
1008                         if (list)
1009                                 commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
1010                 }
1011                 if (revs->first_parent_only)
1012                         break;
1013         }
1014         return 0;
1015 }
1016
1017 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
1018 {
1019         struct commit_list *p;
1020         int left_count = 0, right_count = 0;
1021         int left_first;
1022         struct patch_ids ids;
1023         unsigned cherry_flag;
1024
1025         /* First count the commits on the left and on the right */
1026         for (p = list; p; p = p->next) {
1027                 struct commit *commit = p->item;
1028                 unsigned flags = commit->object.flags;
1029                 if (flags & BOUNDARY)
1030                         ;
1031                 else if (flags & SYMMETRIC_LEFT)
1032                         left_count++;
1033                 else
1034                         right_count++;
1035         }
1036
1037         if (!left_count || !right_count)
1038                 return;
1039
1040         left_first = left_count < right_count;
1041         init_patch_ids(revs->repo, &ids);
1042         ids.diffopts.pathspec = revs->diffopt.pathspec;
1043
1044         /* Compute patch-ids for one side */
1045         for (p = list; p; p = p->next) {
1046                 struct commit *commit = p->item;
1047                 unsigned flags = commit->object.flags;
1048
1049                 if (flags & BOUNDARY)
1050                         continue;
1051                 /*
1052                  * If we have fewer left, left_first is set and we omit
1053                  * commits on the right branch in this loop.  If we have
1054                  * fewer right, we skip the left ones.
1055                  */
1056                 if (left_first != !!(flags & SYMMETRIC_LEFT))
1057                         continue;
1058                 add_commit_patch_id(commit, &ids);
1059         }
1060
1061         /* either cherry_mark or cherry_pick are true */
1062         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
1063
1064         /* Check the other side */
1065         for (p = list; p; p = p->next) {
1066                 struct commit *commit = p->item;
1067                 struct patch_id *id;
1068                 unsigned flags = commit->object.flags;
1069
1070                 if (flags & BOUNDARY)
1071                         continue;
1072                 /*
1073                  * If we have fewer left, left_first is set and we omit
1074                  * commits on the left branch in this loop.
1075                  */
1076                 if (left_first == !!(flags & SYMMETRIC_LEFT))
1077                         continue;
1078
1079                 /*
1080                  * Have we seen the same patch id?
1081                  */
1082                 id = has_commit_patch_id(commit, &ids);
1083                 if (!id)
1084                         continue;
1085
1086                 commit->object.flags |= cherry_flag;
1087                 id->commit->object.flags |= cherry_flag;
1088         }
1089
1090         free_patch_ids(&ids);
1091 }
1092
1093 /* How many extra uninteresting commits we want to see.. */
1094 #define SLOP 5
1095
1096 static int still_interesting(struct commit_list *src, timestamp_t date, int slop,
1097                              struct commit **interesting_cache)
1098 {
1099         /*
1100          * No source list at all? We're definitely done..
1101          */
1102         if (!src)
1103                 return 0;
1104
1105         /*
1106          * Does the destination list contain entries with a date
1107          * before the source list? Definitely _not_ done.
1108          */
1109         if (date <= src->item->date)
1110                 return SLOP;
1111
1112         /*
1113          * Does the source list still have interesting commits in
1114          * it? Definitely not done..
1115          */
1116         if (!everybody_uninteresting(src, interesting_cache))
1117                 return SLOP;
1118
1119         /* Ok, we're closing in.. */
1120         return slop-1;
1121 }
1122
1123 /*
1124  * "rev-list --ancestry-path A..B" computes commits that are ancestors
1125  * of B but not ancestors of A but further limits the result to those
1126  * that are descendants of A.  This takes the list of bottom commits and
1127  * the result of "A..B" without --ancestry-path, and limits the latter
1128  * further to the ones that can reach one of the commits in "bottom".
1129  */
1130 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
1131 {
1132         struct commit_list *p;
1133         struct commit_list *rlist = NULL;
1134         int made_progress;
1135
1136         /*
1137          * Reverse the list so that it will be likely that we would
1138          * process parents before children.
1139          */
1140         for (p = list; p; p = p->next)
1141                 commit_list_insert(p->item, &rlist);
1142
1143         for (p = bottom; p; p = p->next)
1144                 p->item->object.flags |= TMP_MARK;
1145
1146         /*
1147          * Mark the ones that can reach bottom commits in "list",
1148          * in a bottom-up fashion.
1149          */
1150         do {
1151                 made_progress = 0;
1152                 for (p = rlist; p; p = p->next) {
1153                         struct commit *c = p->item;
1154                         struct commit_list *parents;
1155                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
1156                                 continue;
1157                         for (parents = c->parents;
1158                              parents;
1159                              parents = parents->next) {
1160                                 if (!(parents->item->object.flags & TMP_MARK))
1161                                         continue;
1162                                 c->object.flags |= TMP_MARK;
1163                                 made_progress = 1;
1164                                 break;
1165                         }
1166                 }
1167         } while (made_progress);
1168
1169         /*
1170          * NEEDSWORK: decide if we want to remove parents that are
1171          * not marked with TMP_MARK from commit->parents for commits
1172          * in the resulting list.  We may not want to do that, though.
1173          */
1174
1175         /*
1176          * The ones that are not marked with TMP_MARK are uninteresting
1177          */
1178         for (p = list; p; p = p->next) {
1179                 struct commit *c = p->item;
1180                 if (c->object.flags & TMP_MARK)
1181                         continue;
1182                 c->object.flags |= UNINTERESTING;
1183         }
1184
1185         /* We are done with the TMP_MARK */
1186         for (p = list; p; p = p->next)
1187                 p->item->object.flags &= ~TMP_MARK;
1188         for (p = bottom; p; p = p->next)
1189                 p->item->object.flags &= ~TMP_MARK;
1190         free_commit_list(rlist);
1191 }
1192
1193 /*
1194  * Before walking the history, keep the set of "negative" refs the
1195  * caller has asked to exclude.
1196  *
1197  * This is used to compute "rev-list --ancestry-path A..B", as we need
1198  * to filter the result of "A..B" further to the ones that can actually
1199  * reach A.
1200  */
1201 static struct commit_list *collect_bottom_commits(struct commit_list *list)
1202 {
1203         struct commit_list *elem, *bottom = NULL;
1204         for (elem = list; elem; elem = elem->next)
1205                 if (elem->item->object.flags & BOTTOM)
1206                         commit_list_insert(elem->item, &bottom);
1207         return bottom;
1208 }
1209
1210 /* Assumes either left_only or right_only is set */
1211 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
1212 {
1213         struct commit_list *p;
1214
1215         for (p = list; p; p = p->next) {
1216                 struct commit *commit = p->item;
1217
1218                 if (revs->right_only) {
1219                         if (commit->object.flags & SYMMETRIC_LEFT)
1220                                 commit->object.flags |= SHOWN;
1221                 } else  /* revs->left_only is set */
1222                         if (!(commit->object.flags & SYMMETRIC_LEFT))
1223                                 commit->object.flags |= SHOWN;
1224         }
1225 }
1226
1227 static int limit_list(struct rev_info *revs)
1228 {
1229         int slop = SLOP;
1230         timestamp_t date = TIME_MAX;
1231         struct commit_list *list = revs->commits;
1232         struct commit_list *newlist = NULL;
1233         struct commit_list **p = &newlist;
1234         struct commit_list *bottom = NULL;
1235         struct commit *interesting_cache = NULL;
1236
1237         if (revs->ancestry_path) {
1238                 bottom = collect_bottom_commits(list);
1239                 if (!bottom)
1240                         die("--ancestry-path given but there are no bottom commits");
1241         }
1242
1243         while (list) {
1244                 struct commit *commit = pop_commit(&list);
1245                 struct object *obj = &commit->object;
1246                 show_early_output_fn_t show;
1247
1248                 if (commit == interesting_cache)
1249                         interesting_cache = NULL;
1250
1251                 if (revs->max_age != -1 && (commit->date < revs->max_age))
1252                         obj->flags |= UNINTERESTING;
1253                 if (process_parents(revs, commit, &list, NULL) < 0)
1254                         return -1;
1255                 if (obj->flags & UNINTERESTING) {
1256                         mark_parents_uninteresting(commit);
1257                         slop = still_interesting(list, date, slop, &interesting_cache);
1258                         if (slop)
1259                                 continue;
1260                         break;
1261                 }
1262                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1263                         continue;
1264                 date = commit->date;
1265                 p = &commit_list_insert(commit, p)->next;
1266
1267                 show = show_early_output;
1268                 if (!show)
1269                         continue;
1270
1271                 show(revs, newlist);
1272                 show_early_output = NULL;
1273         }
1274         if (revs->cherry_pick || revs->cherry_mark)
1275                 cherry_pick_list(newlist, revs);
1276
1277         if (revs->left_only || revs->right_only)
1278                 limit_left_right(newlist, revs);
1279
1280         if (bottom) {
1281                 limit_to_ancestry(bottom, newlist);
1282                 free_commit_list(bottom);
1283         }
1284
1285         /*
1286          * Check if any commits have become TREESAME by some of their parents
1287          * becoming UNINTERESTING.
1288          */
1289         if (limiting_can_increase_treesame(revs))
1290                 for (list = newlist; list; list = list->next) {
1291                         struct commit *c = list->item;
1292                         if (c->object.flags & (UNINTERESTING | TREESAME))
1293                                 continue;
1294                         update_treesame(revs, c);
1295                 }
1296
1297         revs->commits = newlist;
1298         return 0;
1299 }
1300
1301 /*
1302  * Add an entry to refs->cmdline with the specified information.
1303  * *name is copied.
1304  */
1305 static void add_rev_cmdline(struct rev_info *revs,
1306                             struct object *item,
1307                             const char *name,
1308                             int whence,
1309                             unsigned flags)
1310 {
1311         struct rev_cmdline_info *info = &revs->cmdline;
1312         unsigned int nr = info->nr;
1313
1314         ALLOC_GROW(info->rev, nr + 1, info->alloc);
1315         info->rev[nr].item = item;
1316         info->rev[nr].name = xstrdup(name);
1317         info->rev[nr].whence = whence;
1318         info->rev[nr].flags = flags;
1319         info->nr++;
1320 }
1321
1322 static void add_rev_cmdline_list(struct rev_info *revs,
1323                                  struct commit_list *commit_list,
1324                                  int whence,
1325                                  unsigned flags)
1326 {
1327         while (commit_list) {
1328                 struct object *object = &commit_list->item->object;
1329                 add_rev_cmdline(revs, object, oid_to_hex(&object->oid),
1330                                 whence, flags);
1331                 commit_list = commit_list->next;
1332         }
1333 }
1334
1335 struct all_refs_cb {
1336         int all_flags;
1337         int warned_bad_reflog;
1338         struct rev_info *all_revs;
1339         const char *name_for_errormsg;
1340         struct worktree *wt;
1341 };
1342
1343 int ref_excluded(struct string_list *ref_excludes, const char *path)
1344 {
1345         struct string_list_item *item;
1346
1347         if (!ref_excludes)
1348                 return 0;
1349         for_each_string_list_item(item, ref_excludes) {
1350                 if (!wildmatch(item->string, path, 0))
1351                         return 1;
1352         }
1353         return 0;
1354 }
1355
1356 static int handle_one_ref(const char *path, const struct object_id *oid,
1357                           int flag, void *cb_data)
1358 {
1359         struct all_refs_cb *cb = cb_data;
1360         struct object *object;
1361
1362         if (ref_excluded(cb->all_revs->ref_excludes, path))
1363             return 0;
1364
1365         object = get_reference(cb->all_revs, path, oid, cb->all_flags);
1366         add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
1367         add_pending_oid(cb->all_revs, path, oid, cb->all_flags);
1368         return 0;
1369 }
1370
1371 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
1372         unsigned flags)
1373 {
1374         cb->all_revs = revs;
1375         cb->all_flags = flags;
1376         revs->rev_input_given = 1;
1377         cb->wt = NULL;
1378 }
1379
1380 void clear_ref_exclusion(struct string_list **ref_excludes_p)
1381 {
1382         if (*ref_excludes_p) {
1383                 string_list_clear(*ref_excludes_p, 0);
1384                 free(*ref_excludes_p);
1385         }
1386         *ref_excludes_p = NULL;
1387 }
1388
1389 void add_ref_exclusion(struct string_list **ref_excludes_p, const char *exclude)
1390 {
1391         if (!*ref_excludes_p) {
1392                 *ref_excludes_p = xcalloc(1, sizeof(**ref_excludes_p));
1393                 (*ref_excludes_p)->strdup_strings = 1;
1394         }
1395         string_list_append(*ref_excludes_p, exclude);
1396 }
1397
1398 static void handle_refs(struct ref_store *refs,
1399                         struct rev_info *revs, unsigned flags,
1400                         int (*for_each)(struct ref_store *, each_ref_fn, void *))
1401 {
1402         struct all_refs_cb cb;
1403
1404         if (!refs) {
1405                 /* this could happen with uninitialized submodules */
1406                 return;
1407         }
1408
1409         init_all_refs_cb(&cb, revs, flags);
1410         for_each(refs, handle_one_ref, &cb);
1411 }
1412
1413 static void handle_one_reflog_commit(struct object_id *oid, void *cb_data)
1414 {
1415         struct all_refs_cb *cb = cb_data;
1416         if (!is_null_oid(oid)) {
1417                 struct object *o = parse_object(cb->all_revs->repo, oid);
1418                 if (o) {
1419                         o->flags |= cb->all_flags;
1420                         /* ??? CMDLINEFLAGS ??? */
1421                         add_pending_object(cb->all_revs, o, "");
1422                 }
1423                 else if (!cb->warned_bad_reflog) {
1424                         warning("reflog of '%s' references pruned commits",
1425                                 cb->name_for_errormsg);
1426                         cb->warned_bad_reflog = 1;
1427                 }
1428         }
1429 }
1430
1431 static int handle_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
1432                 const char *email, timestamp_t timestamp, int tz,
1433                 const char *message, void *cb_data)
1434 {
1435         handle_one_reflog_commit(ooid, cb_data);
1436         handle_one_reflog_commit(noid, cb_data);
1437         return 0;
1438 }
1439
1440 static int handle_one_reflog(const char *refname_in_wt,
1441                              const struct object_id *oid,
1442                              int flag, void *cb_data)
1443 {
1444         struct all_refs_cb *cb = cb_data;
1445         struct strbuf refname = STRBUF_INIT;
1446
1447         cb->warned_bad_reflog = 0;
1448         strbuf_worktree_ref(cb->wt, &refname, refname_in_wt);
1449         cb->name_for_errormsg = refname.buf;
1450         refs_for_each_reflog_ent(get_main_ref_store(the_repository),
1451                                  refname.buf,
1452                                  handle_one_reflog_ent, cb_data);
1453         strbuf_release(&refname);
1454         return 0;
1455 }
1456
1457 static void add_other_reflogs_to_pending(struct all_refs_cb *cb)
1458 {
1459         struct worktree **worktrees, **p;
1460
1461         worktrees = get_worktrees(0);
1462         for (p = worktrees; *p; p++) {
1463                 struct worktree *wt = *p;
1464
1465                 if (wt->is_current)
1466                         continue;
1467
1468                 cb->wt = wt;
1469                 refs_for_each_reflog(get_worktree_ref_store(wt),
1470                                      handle_one_reflog,
1471                                      cb);
1472         }
1473         free_worktrees(worktrees);
1474 }
1475
1476 void add_reflogs_to_pending(struct rev_info *revs, unsigned flags)
1477 {
1478         struct all_refs_cb cb;
1479
1480         cb.all_revs = revs;
1481         cb.all_flags = flags;
1482         cb.wt = NULL;
1483         for_each_reflog(handle_one_reflog, &cb);
1484
1485         if (!revs->single_worktree)
1486                 add_other_reflogs_to_pending(&cb);
1487 }
1488
1489 static void add_cache_tree(struct cache_tree *it, struct rev_info *revs,
1490                            struct strbuf *path, unsigned int flags)
1491 {
1492         size_t baselen = path->len;
1493         int i;
1494
1495         if (it->entry_count >= 0) {
1496                 struct tree *tree = lookup_tree(revs->repo, &it->oid);
1497                 tree->object.flags |= flags;
1498                 add_pending_object_with_path(revs, &tree->object, "",
1499                                              040000, path->buf);
1500         }
1501
1502         for (i = 0; i < it->subtree_nr; i++) {
1503                 struct cache_tree_sub *sub = it->down[i];
1504                 strbuf_addf(path, "%s%s", baselen ? "/" : "", sub->name);
1505                 add_cache_tree(sub->cache_tree, revs, path, flags);
1506                 strbuf_setlen(path, baselen);
1507         }
1508
1509 }
1510
1511 static void do_add_index_objects_to_pending(struct rev_info *revs,
1512                                             struct index_state *istate,
1513                                             unsigned int flags)
1514 {
1515         int i;
1516
1517         for (i = 0; i < istate->cache_nr; i++) {
1518                 struct cache_entry *ce = istate->cache[i];
1519                 struct blob *blob;
1520
1521                 if (S_ISGITLINK(ce->ce_mode))
1522                         continue;
1523
1524                 blob = lookup_blob(revs->repo, &ce->oid);
1525                 if (!blob)
1526                         die("unable to add index blob to traversal");
1527                 blob->object.flags |= flags;
1528                 add_pending_object_with_path(revs, &blob->object, "",
1529                                              ce->ce_mode, ce->name);
1530         }
1531
1532         if (istate->cache_tree) {
1533                 struct strbuf path = STRBUF_INIT;
1534                 add_cache_tree(istate->cache_tree, revs, &path, flags);
1535                 strbuf_release(&path);
1536         }
1537 }
1538
1539 void add_index_objects_to_pending(struct rev_info *revs, unsigned int flags)
1540 {
1541         struct worktree **worktrees, **p;
1542
1543         repo_read_index(revs->repo);
1544         do_add_index_objects_to_pending(revs, revs->repo->index, flags);
1545
1546         if (revs->single_worktree)
1547                 return;
1548
1549         worktrees = get_worktrees(0);
1550         for (p = worktrees; *p; p++) {
1551                 struct worktree *wt = *p;
1552                 struct index_state istate = { NULL };
1553
1554                 if (wt->is_current)
1555                         continue; /* current index already taken care of */
1556
1557                 if (read_index_from(&istate,
1558                                     worktree_git_path(wt, "index"),
1559                                     get_worktree_git_dir(wt)) > 0)
1560                         do_add_index_objects_to_pending(revs, &istate, flags);
1561                 discard_index(&istate);
1562         }
1563         free_worktrees(worktrees);
1564 }
1565
1566 static int add_parents_only(struct rev_info *revs, const char *arg_, int flags,
1567                             int exclude_parent)
1568 {
1569         struct object_id oid;
1570         struct object *it;
1571         struct commit *commit;
1572         struct commit_list *parents;
1573         int parent_number;
1574         const char *arg = arg_;
1575
1576         if (*arg == '^') {
1577                 flags ^= UNINTERESTING | BOTTOM;
1578                 arg++;
1579         }
1580         if (get_oid_committish(arg, &oid))
1581                 return 0;
1582         while (1) {
1583                 it = get_reference(revs, arg, &oid, 0);
1584                 if (!it && revs->ignore_missing)
1585                         return 0;
1586                 if (it->type != OBJ_TAG)
1587                         break;
1588                 if (!((struct tag*)it)->tagged)
1589                         return 0;
1590                 oidcpy(&oid, &((struct tag*)it)->tagged->oid);
1591         }
1592         if (it->type != OBJ_COMMIT)
1593                 return 0;
1594         commit = (struct commit *)it;
1595         if (exclude_parent &&
1596             exclude_parent > commit_list_count(commit->parents))
1597                 return 0;
1598         for (parents = commit->parents, parent_number = 1;
1599              parents;
1600              parents = parents->next, parent_number++) {
1601                 if (exclude_parent && parent_number != exclude_parent)
1602                         continue;
1603
1604                 it = &parents->item->object;
1605                 it->flags |= flags;
1606                 add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
1607                 add_pending_object(revs, it, arg);
1608         }
1609         return 1;
1610 }
1611
1612 void repo_init_revisions(struct repository *r,
1613                          struct rev_info *revs,
1614                          const char *prefix)
1615 {
1616         memset(revs, 0, sizeof(*revs));
1617
1618         revs->repo = r;
1619         revs->abbrev = DEFAULT_ABBREV;
1620         revs->ignore_merges = 1;
1621         revs->simplify_history = 1;
1622         revs->pruning.repo = r;
1623         revs->pruning.flags.recursive = 1;
1624         revs->pruning.flags.quick = 1;
1625         revs->pruning.add_remove = file_add_remove;
1626         revs->pruning.change = file_change;
1627         revs->pruning.change_fn_data = revs;
1628         revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1629         revs->dense = 1;
1630         revs->prefix = prefix;
1631         revs->max_age = -1;
1632         revs->min_age = -1;
1633         revs->skip_count = -1;
1634         revs->max_count = -1;
1635         revs->max_parents = -1;
1636         revs->expand_tabs_in_log = -1;
1637
1638         revs->commit_format = CMIT_FMT_DEFAULT;
1639         revs->expand_tabs_in_log_default = 8;
1640
1641         init_grep_defaults(revs->repo);
1642         grep_init(&revs->grep_filter, revs->repo, prefix);
1643         revs->grep_filter.status_only = 1;
1644
1645         repo_diff_setup(revs->repo, &revs->diffopt);
1646         if (prefix && !revs->diffopt.prefix) {
1647                 revs->diffopt.prefix = prefix;
1648                 revs->diffopt.prefix_length = strlen(prefix);
1649         }
1650
1651         revs->notes_opt.use_default_notes = -1;
1652 }
1653
1654 static void add_pending_commit_list(struct rev_info *revs,
1655                                     struct commit_list *commit_list,
1656                                     unsigned int flags)
1657 {
1658         while (commit_list) {
1659                 struct object *object = &commit_list->item->object;
1660                 object->flags |= flags;
1661                 add_pending_object(revs, object, oid_to_hex(&object->oid));
1662                 commit_list = commit_list->next;
1663         }
1664 }
1665
1666 static void prepare_show_merge(struct rev_info *revs)
1667 {
1668         struct commit_list *bases;
1669         struct commit *head, *other;
1670         struct object_id oid;
1671         const char **prune = NULL;
1672         int i, prune_num = 1; /* counting terminating NULL */
1673         struct index_state *istate = revs->repo->index;
1674
1675         if (get_oid("HEAD", &oid))
1676                 die("--merge without HEAD?");
1677         head = lookup_commit_or_die(&oid, "HEAD");
1678         if (get_oid("MERGE_HEAD", &oid))
1679                 die("--merge without MERGE_HEAD?");
1680         other = lookup_commit_or_die(&oid, "MERGE_HEAD");
1681         add_pending_object(revs, &head->object, "HEAD");
1682         add_pending_object(revs, &other->object, "MERGE_HEAD");
1683         bases = get_merge_bases(head, other);
1684         add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
1685         add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
1686         free_commit_list(bases);
1687         head->object.flags |= SYMMETRIC_LEFT;
1688
1689         if (!istate->cache_nr)
1690                 repo_read_index(revs->repo);
1691         for (i = 0; i < istate->cache_nr; i++) {
1692                 const struct cache_entry *ce = istate->cache[i];
1693                 if (!ce_stage(ce))
1694                         continue;
1695                 if (ce_path_match(istate, ce, &revs->prune_data, NULL)) {
1696                         prune_num++;
1697                         REALLOC_ARRAY(prune, prune_num);
1698                         prune[prune_num-2] = ce->name;
1699                         prune[prune_num-1] = NULL;
1700                 }
1701                 while ((i+1 < istate->cache_nr) &&
1702                        ce_same_name(ce, istate->cache[i+1]))
1703                         i++;
1704         }
1705         clear_pathspec(&revs->prune_data);
1706         parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
1707                        PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
1708         revs->limited = 1;
1709 }
1710
1711 static int dotdot_missing(const char *arg, char *dotdot,
1712                           struct rev_info *revs, int symmetric)
1713 {
1714         if (revs->ignore_missing)
1715                 return 0;
1716         /* de-munge so we report the full argument */
1717         *dotdot = '.';
1718         die(symmetric
1719             ? "Invalid symmetric difference expression %s"
1720             : "Invalid revision range %s", arg);
1721 }
1722
1723 static int handle_dotdot_1(const char *arg, char *dotdot,
1724                            struct rev_info *revs, int flags,
1725                            int cant_be_filename,
1726                            struct object_context *a_oc,
1727                            struct object_context *b_oc)
1728 {
1729         const char *a_name, *b_name;
1730         struct object_id a_oid, b_oid;
1731         struct object *a_obj, *b_obj;
1732         unsigned int a_flags, b_flags;
1733         int symmetric = 0;
1734         unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
1735         unsigned int oc_flags = GET_OID_COMMITTISH | GET_OID_RECORD_PATH;
1736
1737         a_name = arg;
1738         if (!*a_name)
1739                 a_name = "HEAD";
1740
1741         b_name = dotdot + 2;
1742         if (*b_name == '.') {
1743                 symmetric = 1;
1744                 b_name++;
1745         }
1746         if (!*b_name)
1747                 b_name = "HEAD";
1748
1749         if (get_oid_with_context(revs->repo, a_name, oc_flags, &a_oid, a_oc) ||
1750             get_oid_with_context(revs->repo, b_name, oc_flags, &b_oid, b_oc))
1751                 return -1;
1752
1753         if (!cant_be_filename) {
1754                 *dotdot = '.';
1755                 verify_non_filename(revs->prefix, arg);
1756                 *dotdot = '\0';
1757         }
1758
1759         a_obj = parse_object(revs->repo, &a_oid);
1760         b_obj = parse_object(revs->repo, &b_oid);
1761         if (!a_obj || !b_obj)
1762                 return dotdot_missing(arg, dotdot, revs, symmetric);
1763
1764         if (!symmetric) {
1765                 /* just A..B */
1766                 b_flags = flags;
1767                 a_flags = flags_exclude;
1768         } else {
1769                 /* A...B -- find merge bases between the two */
1770                 struct commit *a, *b;
1771                 struct commit_list *exclude;
1772
1773                 a = lookup_commit_reference(revs->repo, &a_obj->oid);
1774                 b = lookup_commit_reference(revs->repo, &b_obj->oid);
1775                 if (!a || !b)
1776                         return dotdot_missing(arg, dotdot, revs, symmetric);
1777
1778                 exclude = get_merge_bases(a, b);
1779                 add_rev_cmdline_list(revs, exclude, REV_CMD_MERGE_BASE,
1780                                      flags_exclude);
1781                 add_pending_commit_list(revs, exclude, flags_exclude);
1782                 free_commit_list(exclude);
1783
1784                 b_flags = flags;
1785                 a_flags = flags | SYMMETRIC_LEFT;
1786         }
1787
1788         a_obj->flags |= a_flags;
1789         b_obj->flags |= b_flags;
1790         add_rev_cmdline(revs, a_obj, a_name, REV_CMD_LEFT, a_flags);
1791         add_rev_cmdline(revs, b_obj, b_name, REV_CMD_RIGHT, b_flags);
1792         add_pending_object_with_path(revs, a_obj, a_name, a_oc->mode, a_oc->path);
1793         add_pending_object_with_path(revs, b_obj, b_name, b_oc->mode, b_oc->path);
1794         return 0;
1795 }
1796
1797 static int handle_dotdot(const char *arg,
1798                          struct rev_info *revs, int flags,
1799                          int cant_be_filename)
1800 {
1801         struct object_context a_oc, b_oc;
1802         char *dotdot = strstr(arg, "..");
1803         int ret;
1804
1805         if (!dotdot)
1806                 return -1;
1807
1808         memset(&a_oc, 0, sizeof(a_oc));
1809         memset(&b_oc, 0, sizeof(b_oc));
1810
1811         *dotdot = '\0';
1812         ret = handle_dotdot_1(arg, dotdot, revs, flags, cant_be_filename,
1813                               &a_oc, &b_oc);
1814         *dotdot = '.';
1815
1816         free(a_oc.path);
1817         free(b_oc.path);
1818
1819         return ret;
1820 }
1821
1822 int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
1823 {
1824         struct object_context oc;
1825         char *mark;
1826         struct object *object;
1827         struct object_id oid;
1828         int local_flags;
1829         const char *arg = arg_;
1830         int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
1831         unsigned get_sha1_flags = GET_OID_RECORD_PATH;
1832
1833         flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
1834
1835         if (!cant_be_filename && !strcmp(arg, "..")) {
1836                 /*
1837                  * Just ".."?  That is not a range but the
1838                  * pathspec for the parent directory.
1839                  */
1840                 return -1;
1841         }
1842
1843         if (!handle_dotdot(arg, revs, flags, revarg_opt))
1844                 return 0;
1845
1846         mark = strstr(arg, "^@");
1847         if (mark && !mark[2]) {
1848                 *mark = 0;
1849                 if (add_parents_only(revs, arg, flags, 0))
1850                         return 0;
1851                 *mark = '^';
1852         }
1853         mark = strstr(arg, "^!");
1854         if (mark && !mark[2]) {
1855                 *mark = 0;
1856                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), 0))
1857                         *mark = '^';
1858         }
1859         mark = strstr(arg, "^-");
1860         if (mark) {
1861                 int exclude_parent = 1;
1862
1863                 if (mark[2]) {
1864                         char *end;
1865                         exclude_parent = strtoul(mark + 2, &end, 10);
1866                         if (*end != '\0' || !exclude_parent)
1867                                 return -1;
1868                 }
1869
1870                 *mark = 0;
1871                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), exclude_parent))
1872                         *mark = '^';
1873         }
1874
1875         local_flags = 0;
1876         if (*arg == '^') {
1877                 local_flags = UNINTERESTING | BOTTOM;
1878                 arg++;
1879         }
1880
1881         if (revarg_opt & REVARG_COMMITTISH)
1882                 get_sha1_flags |= GET_OID_COMMITTISH;
1883
1884         if (get_oid_with_context(revs->repo, arg, get_sha1_flags, &oid, &oc))
1885                 return revs->ignore_missing ? 0 : -1;
1886         if (!cant_be_filename)
1887                 verify_non_filename(revs->prefix, arg);
1888         object = get_reference(revs, arg, &oid, flags ^ local_flags);
1889         if (!object)
1890                 return revs->ignore_missing ? 0 : -1;
1891         add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
1892         add_pending_object_with_path(revs, object, arg, oc.mode, oc.path);
1893         free(oc.path);
1894         return 0;
1895 }
1896
1897 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
1898                                      struct argv_array *prune)
1899 {
1900         while (strbuf_getline(sb, stdin) != EOF)
1901                 argv_array_push(prune, sb->buf);
1902 }
1903
1904 static void read_revisions_from_stdin(struct rev_info *revs,
1905                                       struct argv_array *prune)
1906 {
1907         struct strbuf sb;
1908         int seen_dashdash = 0;
1909         int save_warning;
1910
1911         save_warning = warn_on_object_refname_ambiguity;
1912         warn_on_object_refname_ambiguity = 0;
1913
1914         strbuf_init(&sb, 1000);
1915         while (strbuf_getline(&sb, stdin) != EOF) {
1916                 int len = sb.len;
1917                 if (!len)
1918                         break;
1919                 if (sb.buf[0] == '-') {
1920                         if (len == 2 && sb.buf[1] == '-') {
1921                                 seen_dashdash = 1;
1922                                 break;
1923                         }
1924                         die("options not supported in --stdin mode");
1925                 }
1926                 if (handle_revision_arg(sb.buf, revs, 0,
1927                                         REVARG_CANNOT_BE_FILENAME))
1928                         die("bad revision '%s'", sb.buf);
1929         }
1930         if (seen_dashdash)
1931                 read_pathspec_from_stdin(revs, &sb, prune);
1932
1933         strbuf_release(&sb);
1934         warn_on_object_refname_ambiguity = save_warning;
1935 }
1936
1937 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1938 {
1939         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1940 }
1941
1942 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1943 {
1944         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1945 }
1946
1947 static void add_message_grep(struct rev_info *revs, const char *pattern)
1948 {
1949         add_grep(revs, pattern, GREP_PATTERN_BODY);
1950 }
1951
1952 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1953                                int *unkc, const char **unkv,
1954                                const struct setup_revision_opt* opt)
1955 {
1956         const char *arg = argv[0];
1957         const char *optarg;
1958         int argcount;
1959         const unsigned hexsz = the_hash_algo->hexsz;
1960
1961         /* pseudo revision arguments */
1962         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1963             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1964             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1965             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1966             !strcmp(arg, "--bisect") || starts_with(arg, "--glob=") ||
1967             !strcmp(arg, "--indexed-objects") ||
1968             starts_with(arg, "--exclude=") ||
1969             starts_with(arg, "--branches=") || starts_with(arg, "--tags=") ||
1970             starts_with(arg, "--remotes=") || starts_with(arg, "--no-walk="))
1971         {
1972                 unkv[(*unkc)++] = arg;
1973                 return 1;
1974         }
1975
1976         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1977                 revs->max_count = atoi(optarg);
1978                 revs->no_walk = 0;
1979                 return argcount;
1980         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1981                 revs->skip_count = atoi(optarg);
1982                 return argcount;
1983         } else if ((*arg == '-') && isdigit(arg[1])) {
1984                 /* accept -<digit>, like traditional "head" */
1985                 if (strtol_i(arg + 1, 10, &revs->max_count) < 0 ||
1986                     revs->max_count < 0)
1987                         die("'%s': not a non-negative integer", arg + 1);
1988                 revs->no_walk = 0;
1989         } else if (!strcmp(arg, "-n")) {
1990                 if (argc <= 1)
1991                         return error("-n requires an argument");
1992                 revs->max_count = atoi(argv[1]);
1993                 revs->no_walk = 0;
1994                 return 2;
1995         } else if (skip_prefix(arg, "-n", &optarg)) {
1996                 revs->max_count = atoi(optarg);
1997                 revs->no_walk = 0;
1998         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1999                 revs->max_age = atoi(optarg);
2000                 return argcount;
2001         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
2002                 revs->max_age = approxidate(optarg);
2003                 return argcount;
2004         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
2005                 revs->max_age = approxidate(optarg);
2006                 return argcount;
2007         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
2008                 revs->min_age = atoi(optarg);
2009                 return argcount;
2010         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
2011                 revs->min_age = approxidate(optarg);
2012                 return argcount;
2013         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
2014                 revs->min_age = approxidate(optarg);
2015                 return argcount;
2016         } else if (!strcmp(arg, "--first-parent")) {
2017                 revs->first_parent_only = 1;
2018         } else if (!strcmp(arg, "--ancestry-path")) {
2019                 revs->ancestry_path = 1;
2020                 revs->simplify_history = 0;
2021                 revs->limited = 1;
2022         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
2023                 init_reflog_walk(&revs->reflog_info);
2024         } else if (!strcmp(arg, "--default")) {
2025                 if (argc <= 1)
2026                         return error("bad --default argument");
2027                 revs->def = argv[1];
2028                 return 2;
2029         } else if (!strcmp(arg, "--merge")) {
2030                 revs->show_merge = 1;
2031         } else if (!strcmp(arg, "--topo-order")) {
2032                 revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
2033                 revs->topo_order = 1;
2034         } else if (!strcmp(arg, "--simplify-merges")) {
2035                 revs->simplify_merges = 1;
2036                 revs->topo_order = 1;
2037                 revs->rewrite_parents = 1;
2038                 revs->simplify_history = 0;
2039                 revs->limited = 1;
2040         } else if (!strcmp(arg, "--simplify-by-decoration")) {
2041                 revs->simplify_merges = 1;
2042                 revs->topo_order = 1;
2043                 revs->rewrite_parents = 1;
2044                 revs->simplify_history = 0;
2045                 revs->simplify_by_decoration = 1;
2046                 revs->limited = 1;
2047                 revs->prune = 1;
2048                 load_ref_decorations(NULL, DECORATE_SHORT_REFS);
2049         } else if (!strcmp(arg, "--date-order")) {
2050                 revs->sort_order = REV_SORT_BY_COMMIT_DATE;
2051                 revs->topo_order = 1;
2052         } else if (!strcmp(arg, "--author-date-order")) {
2053                 revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
2054                 revs->topo_order = 1;
2055         } else if (!strcmp(arg, "--early-output")) {
2056                 revs->early_output = 100;
2057                 revs->topo_order = 1;
2058         } else if (skip_prefix(arg, "--early-output=", &optarg)) {
2059                 if (strtoul_ui(optarg, 10, &revs->early_output) < 0)
2060                         die("'%s': not a non-negative integer", optarg);
2061                 revs->topo_order = 1;
2062         } else if (!strcmp(arg, "--parents")) {
2063                 revs->rewrite_parents = 1;
2064                 revs->print_parents = 1;
2065         } else if (!strcmp(arg, "--dense")) {
2066                 revs->dense = 1;
2067         } else if (!strcmp(arg, "--sparse")) {
2068                 revs->dense = 0;
2069         } else if (!strcmp(arg, "--in-commit-order")) {
2070                 revs->tree_blobs_in_commit_order = 1;
2071         } else if (!strcmp(arg, "--remove-empty")) {
2072                 revs->remove_empty_trees = 1;
2073         } else if (!strcmp(arg, "--merges")) {
2074                 revs->min_parents = 2;
2075         } else if (!strcmp(arg, "--no-merges")) {
2076                 revs->max_parents = 1;
2077         } else if (skip_prefix(arg, "--min-parents=", &optarg)) {
2078                 revs->min_parents = atoi(optarg);
2079         } else if (!strcmp(arg, "--no-min-parents")) {
2080                 revs->min_parents = 0;
2081         } else if (skip_prefix(arg, "--max-parents=", &optarg)) {
2082                 revs->max_parents = atoi(optarg);
2083         } else if (!strcmp(arg, "--no-max-parents")) {
2084                 revs->max_parents = -1;
2085         } else if (!strcmp(arg, "--boundary")) {
2086                 revs->boundary = 1;
2087         } else if (!strcmp(arg, "--left-right")) {
2088                 revs->left_right = 1;
2089         } else if (!strcmp(arg, "--left-only")) {
2090                 if (revs->right_only)
2091                         die("--left-only is incompatible with --right-only"
2092                             " or --cherry");
2093                 revs->left_only = 1;
2094         } else if (!strcmp(arg, "--right-only")) {
2095                 if (revs->left_only)
2096                         die("--right-only is incompatible with --left-only");
2097                 revs->right_only = 1;
2098         } else if (!strcmp(arg, "--cherry")) {
2099                 if (revs->left_only)
2100                         die("--cherry is incompatible with --left-only");
2101                 revs->cherry_mark = 1;
2102                 revs->right_only = 1;
2103                 revs->max_parents = 1;
2104                 revs->limited = 1;
2105         } else if (!strcmp(arg, "--count")) {
2106                 revs->count = 1;
2107         } else if (!strcmp(arg, "--cherry-mark")) {
2108                 if (revs->cherry_pick)
2109                         die("--cherry-mark is incompatible with --cherry-pick");
2110                 revs->cherry_mark = 1;
2111                 revs->limited = 1; /* needs limit_list() */
2112         } else if (!strcmp(arg, "--cherry-pick")) {
2113                 if (revs->cherry_mark)
2114                         die("--cherry-pick is incompatible with --cherry-mark");
2115                 revs->cherry_pick = 1;
2116                 revs->limited = 1;
2117         } else if (!strcmp(arg, "--objects")) {
2118                 revs->tag_objects = 1;
2119                 revs->tree_objects = 1;
2120                 revs->blob_objects = 1;
2121         } else if (!strcmp(arg, "--objects-edge")) {
2122                 revs->tag_objects = 1;
2123                 revs->tree_objects = 1;
2124                 revs->blob_objects = 1;
2125                 revs->edge_hint = 1;
2126         } else if (!strcmp(arg, "--objects-edge-aggressive")) {
2127                 revs->tag_objects = 1;
2128                 revs->tree_objects = 1;
2129                 revs->blob_objects = 1;
2130                 revs->edge_hint = 1;
2131                 revs->edge_hint_aggressive = 1;
2132         } else if (!strcmp(arg, "--verify-objects")) {
2133                 revs->tag_objects = 1;
2134                 revs->tree_objects = 1;
2135                 revs->blob_objects = 1;
2136                 revs->verify_objects = 1;
2137         } else if (!strcmp(arg, "--unpacked")) {
2138                 revs->unpacked = 1;
2139         } else if (starts_with(arg, "--unpacked=")) {
2140                 die("--unpacked=<packfile> no longer supported.");
2141         } else if (!strcmp(arg, "-r")) {
2142                 revs->diff = 1;
2143                 revs->diffopt.flags.recursive = 1;
2144         } else if (!strcmp(arg, "-t")) {
2145                 revs->diff = 1;
2146                 revs->diffopt.flags.recursive = 1;
2147                 revs->diffopt.flags.tree_in_recursive = 1;
2148         } else if (!strcmp(arg, "-m")) {
2149                 revs->ignore_merges = 0;
2150         } else if (!strcmp(arg, "-c")) {
2151                 revs->diff = 1;
2152                 revs->dense_combined_merges = 0;
2153                 revs->combine_merges = 1;
2154         } else if (!strcmp(arg, "--combined-all-paths")) {
2155                 revs->diff = 1;
2156                 revs->combined_all_paths = 1;
2157         } else if (!strcmp(arg, "--cc")) {
2158                 revs->diff = 1;
2159                 revs->dense_combined_merges = 1;
2160                 revs->combine_merges = 1;
2161         } else if (!strcmp(arg, "-v")) {
2162                 revs->verbose_header = 1;
2163         } else if (!strcmp(arg, "--pretty")) {
2164                 revs->verbose_header = 1;
2165                 revs->pretty_given = 1;
2166                 get_commit_format(NULL, revs);
2167         } else if (skip_prefix(arg, "--pretty=", &optarg) ||
2168                    skip_prefix(arg, "--format=", &optarg)) {
2169                 /*
2170                  * Detached form ("--pretty X" as opposed to "--pretty=X")
2171                  * not allowed, since the argument is optional.
2172                  */
2173                 revs->verbose_header = 1;
2174                 revs->pretty_given = 1;
2175                 get_commit_format(optarg, revs);
2176         } else if (!strcmp(arg, "--expand-tabs")) {
2177                 revs->expand_tabs_in_log = 8;
2178         } else if (!strcmp(arg, "--no-expand-tabs")) {
2179                 revs->expand_tabs_in_log = 0;
2180         } else if (skip_prefix(arg, "--expand-tabs=", &arg)) {
2181                 int val;
2182                 if (strtol_i(arg, 10, &val) < 0 || val < 0)
2183                         die("'%s': not a non-negative integer", arg);
2184                 revs->expand_tabs_in_log = val;
2185         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
2186                 revs->show_notes = 1;
2187                 revs->show_notes_given = 1;
2188                 revs->notes_opt.use_default_notes = 1;
2189         } else if (!strcmp(arg, "--show-signature")) {
2190                 revs->show_signature = 1;
2191         } else if (!strcmp(arg, "--no-show-signature")) {
2192                 revs->show_signature = 0;
2193         } else if (!strcmp(arg, "--show-linear-break")) {
2194                 revs->break_bar = "                    ..........";
2195                 revs->track_linear = 1;
2196                 revs->track_first_time = 1;
2197         } else if (skip_prefix(arg, "--show-linear-break=", &optarg)) {
2198                 revs->break_bar = xstrdup(optarg);
2199                 revs->track_linear = 1;
2200                 revs->track_first_time = 1;
2201         } else if (skip_prefix(arg, "--show-notes=", &optarg) ||
2202                    skip_prefix(arg, "--notes=", &optarg)) {
2203                 struct strbuf buf = STRBUF_INIT;
2204                 revs->show_notes = 1;
2205                 revs->show_notes_given = 1;
2206                 if (starts_with(arg, "--show-notes=") &&
2207                     revs->notes_opt.use_default_notes < 0)
2208                         revs->notes_opt.use_default_notes = 1;
2209                 strbuf_addstr(&buf, optarg);
2210                 expand_notes_ref(&buf);
2211                 string_list_append(&revs->notes_opt.extra_notes_refs,
2212                                    strbuf_detach(&buf, NULL));
2213         } else if (!strcmp(arg, "--no-notes")) {
2214                 revs->show_notes = 0;
2215                 revs->show_notes_given = 1;
2216                 revs->notes_opt.use_default_notes = -1;
2217                 /* we have been strdup'ing ourselves, so trick
2218                  * string_list into free()ing strings */
2219                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
2220                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
2221                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
2222         } else if (!strcmp(arg, "--standard-notes")) {
2223                 revs->show_notes_given = 1;
2224                 revs->notes_opt.use_default_notes = 1;
2225         } else if (!strcmp(arg, "--no-standard-notes")) {
2226                 revs->notes_opt.use_default_notes = 0;
2227         } else if (!strcmp(arg, "--oneline")) {
2228                 revs->verbose_header = 1;
2229                 get_commit_format("oneline", revs);
2230                 revs->pretty_given = 1;
2231                 revs->abbrev_commit = 1;
2232         } else if (!strcmp(arg, "--graph")) {
2233                 revs->topo_order = 1;
2234                 revs->rewrite_parents = 1;
2235                 revs->graph = graph_init(revs);
2236         } else if (!strcmp(arg, "--root")) {
2237                 revs->show_root_diff = 1;
2238         } else if (!strcmp(arg, "--no-commit-id")) {
2239                 revs->no_commit_id = 1;
2240         } else if (!strcmp(arg, "--always")) {
2241                 revs->always_show_header = 1;
2242         } else if (!strcmp(arg, "--no-abbrev")) {
2243                 revs->abbrev = 0;
2244         } else if (!strcmp(arg, "--abbrev")) {
2245                 revs->abbrev = DEFAULT_ABBREV;
2246         } else if (skip_prefix(arg, "--abbrev=", &optarg)) {
2247                 revs->abbrev = strtoul(optarg, NULL, 10);
2248                 if (revs->abbrev < MINIMUM_ABBREV)
2249                         revs->abbrev = MINIMUM_ABBREV;
2250                 else if (revs->abbrev > hexsz)
2251                         revs->abbrev = hexsz;
2252         } else if (!strcmp(arg, "--abbrev-commit")) {
2253                 revs->abbrev_commit = 1;
2254                 revs->abbrev_commit_given = 1;
2255         } else if (!strcmp(arg, "--no-abbrev-commit")) {
2256                 revs->abbrev_commit = 0;
2257         } else if (!strcmp(arg, "--full-diff")) {
2258                 revs->diff = 1;
2259                 revs->full_diff = 1;
2260         } else if (!strcmp(arg, "--full-history")) {
2261                 revs->simplify_history = 0;
2262         } else if (!strcmp(arg, "--relative-date")) {
2263                 revs->date_mode.type = DATE_RELATIVE;
2264                 revs->date_mode_explicit = 1;
2265         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
2266                 parse_date_format(optarg, &revs->date_mode);
2267                 revs->date_mode_explicit = 1;
2268                 return argcount;
2269         } else if (!strcmp(arg, "--log-size")) {
2270                 revs->show_log_size = 1;
2271         }
2272         /*
2273          * Grepping the commit log
2274          */
2275         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
2276                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
2277                 return argcount;
2278         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
2279                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
2280                 return argcount;
2281         } else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
2282                 add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
2283                 return argcount;
2284         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
2285                 add_message_grep(revs, optarg);
2286                 return argcount;
2287         } else if (!strcmp(arg, "--grep-debug")) {
2288                 revs->grep_filter.debug = 1;
2289         } else if (!strcmp(arg, "--basic-regexp")) {
2290                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_BRE;
2291         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
2292                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_ERE;
2293         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
2294                 revs->grep_filter.ignore_case = 1;
2295                 revs->diffopt.pickaxe_opts |= DIFF_PICKAXE_IGNORE_CASE;
2296         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
2297                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_FIXED;
2298         } else if (!strcmp(arg, "--perl-regexp") || !strcmp(arg, "-P")) {
2299                 revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_PCRE;
2300         } else if (!strcmp(arg, "--all-match")) {
2301                 revs->grep_filter.all_match = 1;
2302         } else if (!strcmp(arg, "--invert-grep")) {
2303                 revs->invert_grep = 1;
2304         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
2305                 if (strcmp(optarg, "none"))
2306                         git_log_output_encoding = xstrdup(optarg);
2307                 else
2308                         git_log_output_encoding = "";
2309                 return argcount;
2310         } else if (!strcmp(arg, "--reverse")) {
2311                 revs->reverse ^= 1;
2312         } else if (!strcmp(arg, "--children")) {
2313                 revs->children.name = "children";
2314                 revs->limited = 1;
2315         } else if (!strcmp(arg, "--ignore-missing")) {
2316                 revs->ignore_missing = 1;
2317         } else if (opt && opt->allow_exclude_promisor_objects &&
2318                    !strcmp(arg, "--exclude-promisor-objects")) {
2319                 if (fetch_if_missing)
2320                         BUG("exclude_promisor_objects can only be used when fetch_if_missing is 0");
2321                 revs->exclude_promisor_objects = 1;
2322         } else {
2323                 int opts = diff_opt_parse(&revs->diffopt, argv, argc, revs->prefix);
2324                 if (!opts)
2325                         unkv[(*unkc)++] = arg;
2326                 return opts;
2327         }
2328         if (revs->graph && revs->track_linear)
2329                 die("--show-linear-break and --graph are incompatible");
2330
2331         return 1;
2332 }
2333
2334 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
2335                         const struct option *options,
2336                         const char * const usagestr[])
2337 {
2338         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
2339                                     &ctx->cpidx, ctx->out, NULL);
2340         if (n <= 0) {
2341                 error("unknown option `%s'", ctx->argv[0]);
2342                 usage_with_options(usagestr, options);
2343         }
2344         ctx->argv += n;
2345         ctx->argc -= n;
2346 }
2347
2348 static int for_each_bisect_ref(struct ref_store *refs, each_ref_fn fn,
2349                                void *cb_data, const char *term)
2350 {
2351         struct strbuf bisect_refs = STRBUF_INIT;
2352         int status;
2353         strbuf_addf(&bisect_refs, "refs/bisect/%s", term);
2354         status = refs_for_each_fullref_in(refs, bisect_refs.buf, fn, cb_data, 0);
2355         strbuf_release(&bisect_refs);
2356         return status;
2357 }
2358
2359 static int for_each_bad_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2360 {
2361         return for_each_bisect_ref(refs, fn, cb_data, term_bad);
2362 }
2363
2364 static int for_each_good_bisect_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
2365 {
2366         return for_each_bisect_ref(refs, fn, cb_data, term_good);
2367 }
2368
2369 static int handle_revision_pseudo_opt(const char *submodule,
2370                                 struct rev_info *revs,
2371                                 int argc, const char **argv, int *flags)
2372 {
2373         const char *arg = argv[0];
2374         const char *optarg;
2375         struct ref_store *refs;
2376         int argcount;
2377
2378         if (submodule) {
2379                 /*
2380                  * We need some something like get_submodule_worktrees()
2381                  * before we can go through all worktrees of a submodule,
2382                  * .e.g with adding all HEADs from --all, which is not
2383                  * supported right now, so stick to single worktree.
2384                  */
2385                 if (!revs->single_worktree)
2386                         BUG("--single-worktree cannot be used together with submodule");
2387                 refs = get_submodule_ref_store(submodule);
2388         } else
2389                 refs = get_main_ref_store(revs->repo);
2390
2391         /*
2392          * NOTE!
2393          *
2394          * Commands like "git shortlog" will not accept the options below
2395          * unless parse_revision_opt queues them (as opposed to erroring
2396          * out).
2397          *
2398          * When implementing your new pseudo-option, remember to
2399          * register it in the list at the top of handle_revision_opt.
2400          */
2401         if (!strcmp(arg, "--all")) {
2402                 handle_refs(refs, revs, *flags, refs_for_each_ref);
2403                 handle_refs(refs, revs, *flags, refs_head_ref);
2404                 if (!revs->single_worktree) {
2405                         struct all_refs_cb cb;
2406
2407                         init_all_refs_cb(&cb, revs, *flags);
2408                         other_head_refs(handle_one_ref, &cb);
2409                 }
2410                 clear_ref_exclusion(&revs->ref_excludes);
2411         } else if (!strcmp(arg, "--branches")) {
2412                 handle_refs(refs, revs, *flags, refs_for_each_branch_ref);
2413                 clear_ref_exclusion(&revs->ref_excludes);
2414         } else if (!strcmp(arg, "--bisect")) {
2415                 read_bisect_terms(&term_bad, &term_good);
2416                 handle_refs(refs, revs, *flags, for_each_bad_bisect_ref);
2417                 handle_refs(refs, revs, *flags ^ (UNINTERESTING | BOTTOM),
2418                             for_each_good_bisect_ref);
2419                 revs->bisect = 1;
2420         } else if (!strcmp(arg, "--tags")) {
2421                 handle_refs(refs, revs, *flags, refs_for_each_tag_ref);
2422                 clear_ref_exclusion(&revs->ref_excludes);
2423         } else if (!strcmp(arg, "--remotes")) {
2424                 handle_refs(refs, revs, *flags, refs_for_each_remote_ref);
2425                 clear_ref_exclusion(&revs->ref_excludes);
2426         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
2427                 struct all_refs_cb cb;
2428                 init_all_refs_cb(&cb, revs, *flags);
2429                 for_each_glob_ref(handle_one_ref, optarg, &cb);
2430                 clear_ref_exclusion(&revs->ref_excludes);
2431                 return argcount;
2432         } else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
2433                 add_ref_exclusion(&revs->ref_excludes, optarg);
2434                 return argcount;
2435         } else if (skip_prefix(arg, "--branches=", &optarg)) {
2436                 struct all_refs_cb cb;
2437                 init_all_refs_cb(&cb, revs, *flags);
2438                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/heads/", &cb);
2439                 clear_ref_exclusion(&revs->ref_excludes);
2440         } else if (skip_prefix(arg, "--tags=", &optarg)) {
2441                 struct all_refs_cb cb;
2442                 init_all_refs_cb(&cb, revs, *flags);
2443                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/tags/", &cb);
2444                 clear_ref_exclusion(&revs->ref_excludes);
2445         } else if (skip_prefix(arg, "--remotes=", &optarg)) {
2446                 struct all_refs_cb cb;
2447                 init_all_refs_cb(&cb, revs, *flags);
2448                 for_each_glob_ref_in(handle_one_ref, optarg, "refs/remotes/", &cb);
2449                 clear_ref_exclusion(&revs->ref_excludes);
2450         } else if (!strcmp(arg, "--reflog")) {
2451                 add_reflogs_to_pending(revs, *flags);
2452         } else if (!strcmp(arg, "--indexed-objects")) {
2453                 add_index_objects_to_pending(revs, *flags);
2454         } else if (!strcmp(arg, "--not")) {
2455                 *flags ^= UNINTERESTING | BOTTOM;
2456         } else if (!strcmp(arg, "--no-walk")) {
2457                 revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2458         } else if (skip_prefix(arg, "--no-walk=", &optarg)) {
2459                 /*
2460                  * Detached form ("--no-walk X" as opposed to "--no-walk=X")
2461                  * not allowed, since the argument is optional.
2462                  */
2463                 if (!strcmp(optarg, "sorted"))
2464                         revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2465                 else if (!strcmp(optarg, "unsorted"))
2466                         revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
2467                 else
2468                         return error("invalid argument to --no-walk");
2469         } else if (!strcmp(arg, "--do-walk")) {
2470                 revs->no_walk = 0;
2471         } else if (!strcmp(arg, "--single-worktree")) {
2472                 revs->single_worktree = 1;
2473         } else {
2474                 return 0;
2475         }
2476
2477         return 1;
2478 }
2479
2480 static void NORETURN diagnose_missing_default(const char *def)
2481 {
2482         int flags;
2483         const char *refname;
2484
2485         refname = resolve_ref_unsafe(def, 0, NULL, &flags);
2486         if (!refname || !(flags & REF_ISSYMREF) || (flags & REF_ISBROKEN))
2487                 die(_("your current branch appears to be broken"));
2488
2489         skip_prefix(refname, "refs/heads/", &refname);
2490         die(_("your current branch '%s' does not have any commits yet"),
2491             refname);
2492 }
2493
2494 /*
2495  * Parse revision information, filling in the "rev_info" structure,
2496  * and removing the used arguments from the argument list.
2497  *
2498  * Returns the number of arguments left that weren't recognized
2499  * (which are also moved to the head of the argument list)
2500  */
2501 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
2502 {
2503         int i, flags, left, seen_dashdash, got_rev_arg = 0, revarg_opt;
2504         struct argv_array prune_data = ARGV_ARRAY_INIT;
2505         const char *submodule = NULL;
2506
2507         if (opt)
2508                 submodule = opt->submodule;
2509
2510         /* First, search for "--" */
2511         if (opt && opt->assume_dashdash) {
2512                 seen_dashdash = 1;
2513         } else {
2514                 seen_dashdash = 0;
2515                 for (i = 1; i < argc; i++) {
2516                         const char *arg = argv[i];
2517                         if (strcmp(arg, "--"))
2518                                 continue;
2519                         argv[i] = NULL;
2520                         argc = i;
2521                         if (argv[i + 1])
2522                                 argv_array_pushv(&prune_data, argv + i + 1);
2523                         seen_dashdash = 1;
2524                         break;
2525                 }
2526         }
2527
2528         /* Second, deal with arguments and options */
2529         flags = 0;
2530         revarg_opt = opt ? opt->revarg_opt : 0;
2531         if (seen_dashdash)
2532                 revarg_opt |= REVARG_CANNOT_BE_FILENAME;
2533         for (left = i = 1; i < argc; i++) {
2534                 const char *arg = argv[i];
2535                 if (*arg == '-') {
2536                         int opts;
2537
2538                         opts = handle_revision_pseudo_opt(submodule,
2539                                                 revs, argc - i, argv + i,
2540                                                 &flags);
2541                         if (opts > 0) {
2542                                 i += opts - 1;
2543                                 continue;
2544                         }
2545
2546                         if (!strcmp(arg, "--stdin")) {
2547                                 if (revs->disable_stdin) {
2548                                         argv[left++] = arg;
2549                                         continue;
2550                                 }
2551                                 if (revs->read_from_stdin++)
2552                                         die("--stdin given twice?");
2553                                 read_revisions_from_stdin(revs, &prune_data);
2554                                 continue;
2555                         }
2556
2557                         opts = handle_revision_opt(revs, argc - i, argv + i,
2558                                                    &left, argv, opt);
2559                         if (opts > 0) {
2560                                 i += opts - 1;
2561                                 continue;
2562                         }
2563                         if (opts < 0)
2564                                 exit(128);
2565                         continue;
2566                 }
2567
2568
2569                 if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
2570                         int j;
2571                         if (seen_dashdash || *arg == '^')
2572                                 die("bad revision '%s'", arg);
2573
2574                         /* If we didn't have a "--":
2575                          * (1) all filenames must exist;
2576                          * (2) all rev-args must not be interpretable
2577                          *     as a valid filename.
2578                          * but the latter we have checked in the main loop.
2579                          */
2580                         for (j = i; j < argc; j++)
2581                                 verify_filename(revs->prefix, argv[j], j == i);
2582
2583                         argv_array_pushv(&prune_data, argv + i);
2584                         break;
2585                 }
2586                 else
2587                         got_rev_arg = 1;
2588         }
2589
2590         if (prune_data.argc) {
2591                 /*
2592                  * If we need to introduce the magic "a lone ':' means no
2593                  * pathspec whatsoever", here is the place to do so.
2594                  *
2595                  * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
2596                  *      prune_data.nr = 0;
2597                  *      prune_data.alloc = 0;
2598                  *      free(prune_data.path);
2599                  *      prune_data.path = NULL;
2600                  * } else {
2601                  *      terminate prune_data.alloc with NULL and
2602                  *      call init_pathspec() to set revs->prune_data here.
2603                  * }
2604                  */
2605                 parse_pathspec(&revs->prune_data, 0, 0,
2606                                revs->prefix, prune_data.argv);
2607         }
2608         argv_array_clear(&prune_data);
2609
2610         if (revs->def == NULL)
2611                 revs->def = opt ? opt->def : NULL;
2612         if (opt && opt->tweak)
2613                 opt->tweak(revs, opt);
2614         if (revs->show_merge)
2615                 prepare_show_merge(revs);
2616         if (revs->def && !revs->pending.nr && !revs->rev_input_given && !got_rev_arg) {
2617                 struct object_id oid;
2618                 struct object *object;
2619                 struct object_context oc;
2620                 if (get_oid_with_context(revs->repo, revs->def, 0, &oid, &oc))
2621                         diagnose_missing_default(revs->def);
2622                 object = get_reference(revs, revs->def, &oid, 0);
2623                 add_pending_object_with_mode(revs, object, revs->def, oc.mode);
2624         }
2625
2626         /* Did the user ask for any diff output? Run the diff! */
2627         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
2628                 revs->diff = 1;
2629
2630         /* Pickaxe, diff-filter and rename following need diffs */
2631         if ((revs->diffopt.pickaxe_opts & DIFF_PICKAXE_KINDS_MASK) ||
2632             revs->diffopt.filter ||
2633             revs->diffopt.flags.follow_renames)
2634                 revs->diff = 1;
2635
2636         if (revs->diffopt.objfind)
2637                 revs->simplify_history = 0;
2638
2639         if (revs->topo_order && !generation_numbers_enabled(the_repository))
2640                 revs->limited = 1;
2641
2642         if (revs->prune_data.nr) {
2643                 copy_pathspec(&revs->pruning.pathspec, &revs->prune_data);
2644                 /* Can't prune commits with rename following: the paths change.. */
2645                 if (!revs->diffopt.flags.follow_renames)
2646                         revs->prune = 1;
2647                 if (!revs->full_diff)
2648                         copy_pathspec(&revs->diffopt.pathspec,
2649                                       &revs->prune_data);
2650         }
2651         if (revs->combine_merges)
2652                 revs->ignore_merges = 0;
2653         if (revs->combined_all_paths && !revs->combine_merges)
2654                 die("--combined-all-paths makes no sense without -c or --cc");
2655
2656         revs->diffopt.abbrev = revs->abbrev;
2657
2658         if (revs->line_level_traverse) {
2659                 revs->limited = 1;
2660                 revs->topo_order = 1;
2661         }
2662
2663         diff_setup_done(&revs->diffopt);
2664
2665         grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
2666                                  &revs->grep_filter);
2667         compile_grep_patterns(&revs->grep_filter);
2668
2669         if (revs->reverse && revs->reflog_info)
2670                 die("cannot combine --reverse with --walk-reflogs");
2671         if (revs->reflog_info && revs->limited)
2672                 die("cannot combine --walk-reflogs with history-limiting options");
2673         if (revs->rewrite_parents && revs->children.name)
2674                 die("cannot combine --parents and --children");
2675
2676         /*
2677          * Limitations on the graph functionality
2678          */
2679         if (revs->reverse && revs->graph)
2680                 die("cannot combine --reverse with --graph");
2681
2682         if (revs->reflog_info && revs->graph)
2683                 die("cannot combine --walk-reflogs with --graph");
2684         if (revs->no_walk && revs->graph)
2685                 die("cannot combine --no-walk with --graph");
2686         if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
2687                 die("cannot use --grep-reflog without --walk-reflogs");
2688
2689         if (revs->first_parent_only && revs->bisect)
2690                 die(_("--first-parent is incompatible with --bisect"));
2691
2692         if (revs->expand_tabs_in_log < 0)
2693                 revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;
2694
2695         return left;
2696 }
2697
2698 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
2699 {
2700         struct commit_list *l = xcalloc(1, sizeof(*l));
2701
2702         l->item = child;
2703         l->next = add_decoration(&revs->children, &parent->object, l);
2704 }
2705
2706 static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
2707 {
2708         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2709         struct commit_list **pp, *p;
2710         int surviving_parents;
2711
2712         /* Examine existing parents while marking ones we have seen... */
2713         pp = &commit->parents;
2714         surviving_parents = 0;
2715         while ((p = *pp) != NULL) {
2716                 struct commit *parent = p->item;
2717                 if (parent->object.flags & TMP_MARK) {
2718                         *pp = p->next;
2719                         if (ts)
2720                                 compact_treesame(revs, commit, surviving_parents);
2721                         continue;
2722                 }
2723                 parent->object.flags |= TMP_MARK;
2724                 surviving_parents++;
2725                 pp = &p->next;
2726         }
2727         /* clear the temporary mark */
2728         for (p = commit->parents; p; p = p->next) {
2729                 p->item->object.flags &= ~TMP_MARK;
2730         }
2731         /* no update_treesame() - removing duplicates can't affect TREESAME */
2732         return surviving_parents;
2733 }
2734
2735 struct merge_simplify_state {
2736         struct commit *simplified;
2737 };
2738
2739 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
2740 {
2741         struct merge_simplify_state *st;
2742
2743         st = lookup_decoration(&revs->merge_simplification, &commit->object);
2744         if (!st) {
2745                 st = xcalloc(1, sizeof(*st));
2746                 add_decoration(&revs->merge_simplification, &commit->object, st);
2747         }
2748         return st;
2749 }
2750
2751 static int mark_redundant_parents(struct rev_info *revs, struct commit *commit)
2752 {
2753         struct commit_list *h = reduce_heads(commit->parents);
2754         int i = 0, marked = 0;
2755         struct commit_list *po, *pn;
2756
2757         /* Want these for sanity-checking only */
2758         int orig_cnt = commit_list_count(commit->parents);
2759         int cnt = commit_list_count(h);
2760
2761         /*
2762          * Not ready to remove items yet, just mark them for now, based
2763          * on the output of reduce_heads(). reduce_heads outputs the reduced
2764          * set in its original order, so this isn't too hard.
2765          */
2766         po = commit->parents;
2767         pn = h;
2768         while (po) {
2769                 if (pn && po->item == pn->item) {
2770                         pn = pn->next;
2771                         i++;
2772                 } else {
2773                         po->item->object.flags |= TMP_MARK;
2774                         marked++;
2775                 }
2776                 po=po->next;
2777         }
2778
2779         if (i != cnt || cnt+marked != orig_cnt)
2780                 die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
2781
2782         free_commit_list(h);
2783
2784         return marked;
2785 }
2786
2787 static int mark_treesame_root_parents(struct rev_info *revs, struct commit *commit)
2788 {
2789         struct commit_list *p;
2790         int marked = 0;
2791
2792         for (p = commit->parents; p; p = p->next) {
2793                 struct commit *parent = p->item;
2794                 if (!parent->parents && (parent->object.flags & TREESAME)) {
2795                         parent->object.flags |= TMP_MARK;
2796                         marked++;
2797                 }
2798         }
2799
2800         return marked;
2801 }
2802
2803 /*
2804  * Awkward naming - this means one parent we are TREESAME to.
2805  * cf mark_treesame_root_parents: root parents that are TREESAME (to an
2806  * empty tree). Better name suggestions?
2807  */
2808 static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
2809 {
2810         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2811         struct commit *unmarked = NULL, *marked = NULL;
2812         struct commit_list *p;
2813         unsigned n;
2814
2815         for (p = commit->parents, n = 0; p; p = p->next, n++) {
2816                 if (ts->treesame[n]) {
2817                         if (p->item->object.flags & TMP_MARK) {
2818                                 if (!marked)
2819                                         marked = p->item;
2820                         } else {
2821                                 if (!unmarked) {
2822                                         unmarked = p->item;
2823                                         break;
2824                                 }
2825                         }
2826                 }
2827         }
2828
2829         /*
2830          * If we are TREESAME to a marked-for-deletion parent, but not to any
2831          * unmarked parents, unmark the first TREESAME parent. This is the
2832          * parent that the default simplify_history==1 scan would have followed,
2833          * and it doesn't make sense to omit that path when asking for a
2834          * simplified full history. Retaining it improves the chances of
2835          * understanding odd missed merges that took an old version of a file.
2836          *
2837          * Example:
2838          *
2839          *   I--------*X       A modified the file, but mainline merge X used
2840          *    \       /        "-s ours", so took the version from I. X is
2841          *     `-*A--'         TREESAME to I and !TREESAME to A.
2842          *
2843          * Default log from X would produce "I". Without this check,
2844          * --full-history --simplify-merges would produce "I-A-X", showing
2845          * the merge commit X and that it changed A, but not making clear that
2846          * it had just taken the I version. With this check, the topology above
2847          * is retained.
2848          *
2849          * Note that it is possible that the simplification chooses a different
2850          * TREESAME parent from the default, in which case this test doesn't
2851          * activate, and we _do_ drop the default parent. Example:
2852          *
2853          *   I------X         A modified the file, but it was reverted in B,
2854          *    \    /          meaning mainline merge X is TREESAME to both
2855          *    *A-*B           parents.
2856          *
2857          * Default log would produce "I" by following the first parent;
2858          * --full-history --simplify-merges will produce "I-A-B". But this is a
2859          * reasonable result - it presents a logical full history leading from
2860          * I to X, and X is not an important merge.
2861          */
2862         if (!unmarked && marked) {
2863                 marked->object.flags &= ~TMP_MARK;
2864                 return 1;
2865         }
2866
2867         return 0;
2868 }
2869
2870 static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
2871 {
2872         struct commit_list **pp, *p;
2873         int nth_parent, removed = 0;
2874
2875         pp = &commit->parents;
2876         nth_parent = 0;
2877         while ((p = *pp) != NULL) {
2878                 struct commit *parent = p->item;
2879                 if (parent->object.flags & TMP_MARK) {
2880                         parent->object.flags &= ~TMP_MARK;
2881                         *pp = p->next;
2882                         free(p);
2883                         removed++;
2884                         compact_treesame(revs, commit, nth_parent);
2885                         continue;
2886                 }
2887                 pp = &p->next;
2888                 nth_parent++;
2889         }
2890
2891         /* Removing parents can only increase TREESAMEness */
2892         if (removed && !(commit->object.flags & TREESAME))
2893                 update_treesame(revs, commit);
2894
2895         return nth_parent;
2896 }
2897
2898 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
2899 {
2900         struct commit_list *p;
2901         struct commit *parent;
2902         struct merge_simplify_state *st, *pst;
2903         int cnt;
2904
2905         st = locate_simplify_state(revs, commit);
2906
2907         /*
2908          * Have we handled this one?
2909          */
2910         if (st->simplified)
2911                 return tail;
2912
2913         /*
2914          * An UNINTERESTING commit simplifies to itself, so does a
2915          * root commit.  We do not rewrite parents of such commit
2916          * anyway.
2917          */
2918         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
2919                 st->simplified = commit;
2920                 return tail;
2921         }
2922
2923         /*
2924          * Do we know what commit all of our parents that matter
2925          * should be rewritten to?  Otherwise we are not ready to
2926          * rewrite this one yet.
2927          */
2928         for (cnt = 0, p = commit->parents; p; p = p->next) {
2929                 pst = locate_simplify_state(revs, p->item);
2930                 if (!pst->simplified) {
2931                         tail = &commit_list_insert(p->item, tail)->next;
2932                         cnt++;
2933                 }
2934                 if (revs->first_parent_only)
2935                         break;
2936         }
2937         if (cnt) {
2938                 tail = &commit_list_insert(commit, tail)->next;
2939                 return tail;
2940         }
2941
2942         /*
2943          * Rewrite our list of parents. Note that this cannot
2944          * affect our TREESAME flags in any way - a commit is
2945          * always TREESAME to its simplification.
2946          */
2947         for (p = commit->parents; p; p = p->next) {
2948                 pst = locate_simplify_state(revs, p->item);
2949                 p->item = pst->simplified;
2950                 if (revs->first_parent_only)
2951                         break;
2952         }
2953
2954         if (revs->first_parent_only)
2955                 cnt = 1;
2956         else
2957                 cnt = remove_duplicate_parents(revs, commit);
2958
2959         /*
2960          * It is possible that we are a merge and one side branch
2961          * does not have any commit that touches the given paths;
2962          * in such a case, the immediate parent from that branch
2963          * will be rewritten to be the merge base.
2964          *
2965          *      o----X          X: the commit we are looking at;
2966          *     /    /           o: a commit that touches the paths;
2967          * ---o----'
2968          *
2969          * Further, a merge of an independent branch that doesn't
2970          * touch the path will reduce to a treesame root parent:
2971          *
2972          *  ----o----X          X: the commit we are looking at;
2973          *          /           o: a commit that touches the paths;
2974          *         r            r: a root commit not touching the paths
2975          *
2976          * Detect and simplify both cases.
2977          */
2978         if (1 < cnt) {
2979                 int marked = mark_redundant_parents(revs, commit);
2980                 marked += mark_treesame_root_parents(revs, commit);
2981                 if (marked)
2982                         marked -= leave_one_treesame_to_parent(revs, commit);
2983                 if (marked)
2984                         cnt = remove_marked_parents(revs, commit);
2985         }
2986
2987         /*
2988          * A commit simplifies to itself if it is a root, if it is
2989          * UNINTERESTING, if it touches the given paths, or if it is a
2990          * merge and its parents don't simplify to one relevant commit
2991          * (the first two cases are already handled at the beginning of
2992          * this function).
2993          *
2994          * Otherwise, it simplifies to what its sole relevant parent
2995          * simplifies to.
2996          */
2997         if (!cnt ||
2998             (commit->object.flags & UNINTERESTING) ||
2999             !(commit->object.flags & TREESAME) ||
3000             (parent = one_relevant_parent(revs, commit->parents)) == NULL)
3001                 st->simplified = commit;
3002         else {
3003                 pst = locate_simplify_state(revs, parent);
3004                 st->simplified = pst->simplified;
3005         }
3006         return tail;
3007 }
3008
3009 static void simplify_merges(struct rev_info *revs)
3010 {
3011         struct commit_list *list, *next;
3012         struct commit_list *yet_to_do, **tail;
3013         struct commit *commit;
3014
3015         if (!revs->prune)
3016                 return;
3017
3018         /* feed the list reversed */
3019         yet_to_do = NULL;
3020         for (list = revs->commits; list; list = next) {
3021                 commit = list->item;
3022                 next = list->next;
3023                 /*
3024                  * Do not free(list) here yet; the original list
3025                  * is used later in this function.
3026                  */
3027                 commit_list_insert(commit, &yet_to_do);
3028         }
3029         while (yet_to_do) {
3030                 list = yet_to_do;
3031                 yet_to_do = NULL;
3032                 tail = &yet_to_do;
3033                 while (list) {
3034                         commit = pop_commit(&list);
3035                         tail = simplify_one(revs, commit, tail);
3036                 }
3037         }
3038
3039         /* clean up the result, removing the simplified ones */
3040         list = revs->commits;
3041         revs->commits = NULL;
3042         tail = &revs->commits;
3043         while (list) {
3044                 struct merge_simplify_state *st;
3045
3046                 commit = pop_commit(&list);
3047                 st = locate_simplify_state(revs, commit);
3048                 if (st->simplified == commit)
3049                         tail = &commit_list_insert(commit, tail)->next;
3050         }
3051 }
3052
3053 static void set_children(struct rev_info *revs)
3054 {
3055         struct commit_list *l;
3056         for (l = revs->commits; l; l = l->next) {
3057                 struct commit *commit = l->item;
3058                 struct commit_list *p;
3059
3060                 for (p = commit->parents; p; p = p->next)
3061                         add_child(revs, p->item, commit);
3062         }
3063 }
3064
3065 void reset_revision_walk(void)
3066 {
3067         clear_object_flags(SEEN | ADDED | SHOWN);
3068 }
3069
3070 static int mark_uninteresting(const struct object_id *oid,
3071                               struct packed_git *pack,
3072                               uint32_t pos,
3073                               void *cb)
3074 {
3075         struct rev_info *revs = cb;
3076         struct object *o = parse_object(revs->repo, oid);
3077         o->flags |= UNINTERESTING | SEEN;
3078         return 0;
3079 }
3080
3081 define_commit_slab(indegree_slab, int);
3082 define_commit_slab(author_date_slab, timestamp_t);
3083
3084 struct topo_walk_info {
3085         uint32_t min_generation;
3086         struct prio_queue explore_queue;
3087         struct prio_queue indegree_queue;
3088         struct prio_queue topo_queue;
3089         struct indegree_slab indegree;
3090         struct author_date_slab author_date;
3091 };
3092
3093 static inline void test_flag_and_insert(struct prio_queue *q, struct commit *c, int flag)
3094 {
3095         if (c->object.flags & flag)
3096                 return;
3097
3098         c->object.flags |= flag;
3099         prio_queue_put(q, c);
3100 }
3101
3102 static void explore_walk_step(struct rev_info *revs)
3103 {
3104         struct topo_walk_info *info = revs->topo_walk_info;
3105         struct commit_list *p;
3106         struct commit *c = prio_queue_get(&info->explore_queue);
3107
3108         if (!c)
3109                 return;
3110
3111         if (parse_commit_gently(c, 1) < 0)
3112                 return;
3113
3114         if (revs->sort_order == REV_SORT_BY_AUTHOR_DATE)
3115                 record_author_date(&info->author_date, c);
3116
3117         if (revs->max_age != -1 && (c->date < revs->max_age))
3118                 c->object.flags |= UNINTERESTING;
3119
3120         if (process_parents(revs, c, NULL, NULL) < 0)
3121                 return;
3122
3123         if (c->object.flags & UNINTERESTING)
3124                 mark_parents_uninteresting(c);
3125
3126         for (p = c->parents; p; p = p->next)
3127                 test_flag_and_insert(&info->explore_queue, p->item, TOPO_WALK_EXPLORED);
3128 }
3129
3130 static void explore_to_depth(struct rev_info *revs,
3131                              uint32_t gen_cutoff)
3132 {
3133         struct topo_walk_info *info = revs->topo_walk_info;
3134         struct commit *c;
3135         while ((c = prio_queue_peek(&info->explore_queue)) &&
3136                c->generation >= gen_cutoff)
3137                 explore_walk_step(revs);
3138 }
3139
3140 static void indegree_walk_step(struct rev_info *revs)
3141 {
3142         struct commit_list *p;
3143         struct topo_walk_info *info = revs->topo_walk_info;
3144         struct commit *c = prio_queue_get(&info->indegree_queue);
3145
3146         if (!c)
3147                 return;
3148
3149         if (parse_commit_gently(c, 1) < 0)
3150                 return;
3151
3152         explore_to_depth(revs, c->generation);
3153
3154         for (p = c->parents; p; p = p->next) {
3155                 struct commit *parent = p->item;
3156                 int *pi = indegree_slab_at(&info->indegree, parent);
3157
3158                 if (*pi)
3159                         (*pi)++;
3160                 else
3161                         *pi = 2;
3162
3163                 test_flag_and_insert(&info->indegree_queue, parent, TOPO_WALK_INDEGREE);
3164
3165                 if (revs->first_parent_only)
3166                         return;
3167         }
3168 }
3169
3170 static void compute_indegrees_to_depth(struct rev_info *revs,
3171                                        uint32_t gen_cutoff)
3172 {
3173         struct topo_walk_info *info = revs->topo_walk_info;
3174         struct commit *c;
3175         while ((c = prio_queue_peek(&info->indegree_queue)) &&
3176                c->generation >= gen_cutoff)
3177                 indegree_walk_step(revs);
3178 }
3179
3180 static void init_topo_walk(struct rev_info *revs)
3181 {
3182         struct topo_walk_info *info;
3183         struct commit_list *list;
3184         revs->topo_walk_info = xmalloc(sizeof(struct topo_walk_info));
3185         info = revs->topo_walk_info;
3186         memset(info, 0, sizeof(struct topo_walk_info));
3187
3188         init_indegree_slab(&info->indegree);
3189         memset(&info->explore_queue, 0, sizeof(info->explore_queue));
3190         memset(&info->indegree_queue, 0, sizeof(info->indegree_queue));
3191         memset(&info->topo_queue, 0, sizeof(info->topo_queue));
3192
3193         switch (revs->sort_order) {
3194         default: /* REV_SORT_IN_GRAPH_ORDER */
3195                 info->topo_queue.compare = NULL;
3196                 break;
3197         case REV_SORT_BY_COMMIT_DATE:
3198                 info->topo_queue.compare = compare_commits_by_commit_date;
3199                 break;
3200         case REV_SORT_BY_AUTHOR_DATE:
3201                 init_author_date_slab(&info->author_date);
3202                 info->topo_queue.compare = compare_commits_by_author_date;
3203                 info->topo_queue.cb_data = &info->author_date;
3204                 break;
3205         }
3206
3207         info->explore_queue.compare = compare_commits_by_gen_then_commit_date;
3208         info->indegree_queue.compare = compare_commits_by_gen_then_commit_date;
3209
3210         info->min_generation = GENERATION_NUMBER_INFINITY;
3211         for (list = revs->commits; list; list = list->next) {
3212                 struct commit *c = list->item;
3213
3214                 if (parse_commit_gently(c, 1))
3215                         continue;
3216
3217                 test_flag_and_insert(&info->explore_queue, c, TOPO_WALK_EXPLORED);
3218                 test_flag_and_insert(&info->indegree_queue, c, TOPO_WALK_INDEGREE);
3219
3220                 if (c->generation < info->min_generation)
3221                         info->min_generation = c->generation;
3222
3223                 *(indegree_slab_at(&info->indegree, c)) = 1;
3224
3225                 if (revs->sort_order == REV_SORT_BY_AUTHOR_DATE)
3226                         record_author_date(&info->author_date, c);
3227         }
3228         compute_indegrees_to_depth(revs, info->min_generation);
3229
3230         for (list = revs->commits; list; list = list->next) {
3231                 struct commit *c = list->item;
3232
3233                 if (*(indegree_slab_at(&info->indegree, c)) == 1)
3234                         prio_queue_put(&info->topo_queue, c);
3235         }
3236
3237         /*
3238          * This is unfortunate; the initial tips need to be shown
3239          * in the order given from the revision traversal machinery.
3240          */
3241         if (revs->sort_order == REV_SORT_IN_GRAPH_ORDER)
3242                 prio_queue_reverse(&info->topo_queue);
3243 }
3244
3245 static struct commit *next_topo_commit(struct rev_info *revs)
3246 {
3247         struct commit *c;
3248         struct topo_walk_info *info = revs->topo_walk_info;
3249
3250         /* pop next off of topo_queue */
3251         c = prio_queue_get(&info->topo_queue);
3252
3253         if (c)
3254                 *(indegree_slab_at(&info->indegree, c)) = 0;
3255
3256         return c;
3257 }
3258
3259 static void expand_topo_walk(struct rev_info *revs, struct commit *commit)
3260 {
3261         struct commit_list *p;
3262         struct topo_walk_info *info = revs->topo_walk_info;
3263         if (process_parents(revs, commit, NULL, NULL) < 0) {
3264                 if (!revs->ignore_missing_links)
3265                         die("Failed to traverse parents of commit %s",
3266                             oid_to_hex(&commit->object.oid));
3267         }
3268
3269         for (p = commit->parents; p; p = p->next) {
3270                 struct commit *parent = p->item;
3271                 int *pi;
3272
3273                 if (parse_commit_gently(parent, 1) < 0)
3274                         continue;
3275
3276                 if (parent->generation < info->min_generation) {
3277                         info->min_generation = parent->generation;
3278                         compute_indegrees_to_depth(revs, info->min_generation);
3279                 }
3280
3281                 pi = indegree_slab_at(&info->indegree, parent);
3282
3283                 (*pi)--;
3284                 if (*pi == 1)
3285                         prio_queue_put(&info->topo_queue, parent);
3286
3287                 if (revs->first_parent_only)
3288                         return;
3289         }
3290 }
3291
3292 int prepare_revision_walk(struct rev_info *revs)
3293 {
3294         int i;
3295         struct object_array old_pending;
3296         struct commit_list **next = &revs->commits;
3297
3298         memcpy(&old_pending, &revs->pending, sizeof(old_pending));
3299         revs->pending.nr = 0;
3300         revs->pending.alloc = 0;
3301         revs->pending.objects = NULL;
3302         for (i = 0; i < old_pending.nr; i++) {
3303                 struct object_array_entry *e = old_pending.objects + i;
3304                 struct commit *commit = handle_commit(revs, e);
3305                 if (commit) {
3306                         if (!(commit->object.flags & SEEN)) {
3307                                 commit->object.flags |= SEEN;
3308                                 next = commit_list_append(commit, next);
3309                         }
3310                 }
3311         }
3312         object_array_clear(&old_pending);
3313
3314         /* Signal whether we need per-parent treesame decoration */
3315         if (revs->simplify_merges ||
3316             (revs->limited && limiting_can_increase_treesame(revs)))
3317                 revs->treesame.name = "treesame";
3318
3319         if (revs->exclude_promisor_objects) {
3320                 for_each_packed_object(mark_uninteresting, revs,
3321                                        FOR_EACH_OBJECT_PROMISOR_ONLY);
3322         }
3323
3324         if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
3325                 commit_list_sort_by_date(&revs->commits);
3326         if (revs->no_walk)
3327                 return 0;
3328         if (revs->limited) {
3329                 if (limit_list(revs) < 0)
3330                         return -1;
3331                 if (revs->topo_order)
3332                         sort_in_topological_order(&revs->commits, revs->sort_order);
3333         } else if (revs->topo_order)
3334                 init_topo_walk(revs);
3335         if (revs->line_level_traverse)
3336                 line_log_filter(revs);
3337         if (revs->simplify_merges)
3338                 simplify_merges(revs);
3339         if (revs->children.name)
3340                 set_children(revs);
3341         return 0;
3342 }
3343
3344 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
3345 {
3346         struct commit_list *cache = NULL;
3347
3348         for (;;) {
3349                 struct commit *p = *pp;
3350                 if (!revs->limited)
3351                         if (process_parents(revs, p, &revs->commits, &cache) < 0)
3352                                 return rewrite_one_error;
3353                 if (p->object.flags & UNINTERESTING)
3354                         return rewrite_one_ok;
3355                 if (!(p->object.flags & TREESAME))
3356                         return rewrite_one_ok;
3357                 if (!p->parents)
3358                         return rewrite_one_noparents;
3359                 if ((p = one_relevant_parent(revs, p->parents)) == NULL)
3360                         return rewrite_one_ok;
3361                 *pp = p;
3362         }
3363 }
3364
3365 int rewrite_parents(struct rev_info *revs, struct commit *commit,
3366         rewrite_parent_fn_t rewrite_parent)
3367 {
3368         struct commit_list **pp = &commit->parents;
3369         while (*pp) {
3370                 struct commit_list *parent = *pp;
3371                 switch (rewrite_parent(revs, &parent->item)) {
3372                 case rewrite_one_ok:
3373                         break;
3374                 case rewrite_one_noparents:
3375                         *pp = parent->next;
3376                         continue;
3377                 case rewrite_one_error:
3378                         return -1;
3379                 }
3380                 pp = &parent->next;
3381         }
3382         remove_duplicate_parents(revs, commit);
3383         return 0;
3384 }
3385
3386 static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
3387 {
3388         char *person, *endp;
3389         size_t len, namelen, maillen;
3390         const char *name;
3391         const char *mail;
3392         struct ident_split ident;
3393
3394         person = strstr(buf->buf, what);
3395         if (!person)
3396                 return 0;
3397
3398         person += strlen(what);
3399         endp = strchr(person, '\n');
3400         if (!endp)
3401                 return 0;
3402
3403         len = endp - person;
3404
3405         if (split_ident_line(&ident, person, len))
3406                 return 0;
3407
3408         mail = ident.mail_begin;
3409         maillen = ident.mail_end - ident.mail_begin;
3410         name = ident.name_begin;
3411         namelen = ident.name_end - ident.name_begin;
3412
3413         if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
3414                 struct strbuf namemail = STRBUF_INIT;
3415
3416                 strbuf_addf(&namemail, "%.*s <%.*s>",
3417                             (int)namelen, name, (int)maillen, mail);
3418
3419                 strbuf_splice(buf, ident.name_begin - buf->buf,
3420                               ident.mail_end - ident.name_begin + 1,
3421                               namemail.buf, namemail.len);
3422
3423                 strbuf_release(&namemail);
3424
3425                 return 1;
3426         }
3427
3428         return 0;
3429 }
3430
3431 static int commit_match(struct commit *commit, struct rev_info *opt)
3432 {
3433         int retval;
3434         const char *encoding;
3435         const char *message;
3436         struct strbuf buf = STRBUF_INIT;
3437
3438         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
3439                 return 1;
3440
3441         /* Prepend "fake" headers as needed */
3442         if (opt->grep_filter.use_reflog_filter) {
3443                 strbuf_addstr(&buf, "reflog ");
3444                 get_reflog_message(&buf, opt->reflog_info);
3445                 strbuf_addch(&buf, '\n');
3446         }
3447
3448         /*
3449          * We grep in the user's output encoding, under the assumption that it
3450          * is the encoding they are most likely to write their grep pattern
3451          * for. In addition, it means we will match the "notes" encoding below,
3452          * so we will not end up with a buffer that has two different encodings
3453          * in it.
3454          */
3455         encoding = get_log_output_encoding();
3456         message = logmsg_reencode(commit, NULL, encoding);
3457
3458         /* Copy the commit to temporary if we are using "fake" headers */
3459         if (buf.len)
3460                 strbuf_addstr(&buf, message);
3461
3462         if (opt->grep_filter.header_list && opt->mailmap) {
3463                 if (!buf.len)
3464                         strbuf_addstr(&buf, message);
3465
3466                 commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
3467                 commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
3468         }
3469
3470         /* Append "fake" message parts as needed */
3471         if (opt->show_notes) {
3472                 if (!buf.len)
3473                         strbuf_addstr(&buf, message);
3474                 format_display_notes(&commit->object.oid, &buf, encoding, 1);
3475         }
3476
3477         /*
3478          * Find either in the original commit message, or in the temporary.
3479          * Note that we cast away the constness of "message" here. It is
3480          * const because it may come from the cached commit buffer. That's OK,
3481          * because we know that it is modifiable heap memory, and that while
3482          * grep_buffer may modify it for speed, it will restore any
3483          * changes before returning.
3484          */
3485         if (buf.len)
3486                 retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
3487         else
3488                 retval = grep_buffer(&opt->grep_filter,
3489                                      (char *)message, strlen(message));
3490         strbuf_release(&buf);
3491         unuse_commit_buffer(commit, message);
3492         return opt->invert_grep ? !retval : retval;
3493 }
3494
3495 static inline int want_ancestry(const struct rev_info *revs)
3496 {
3497         return (revs->rewrite_parents || revs->children.name);
3498 }
3499
3500 /*
3501  * Return a timestamp to be used for --since/--until comparisons for this
3502  * commit, based on the revision options.
3503  */
3504 static timestamp_t comparison_date(const struct rev_info *revs,
3505                                    struct commit *commit)
3506 {
3507         return revs->reflog_info ?
3508                 get_reflog_timestamp(revs->reflog_info) :
3509                 commit->date;
3510 }
3511
3512 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
3513 {
3514         if (commit->object.flags & SHOWN)
3515                 return commit_ignore;
3516         if (revs->unpacked && has_object_pack(&commit->object.oid))
3517                 return commit_ignore;
3518         if (commit->object.flags & UNINTERESTING)
3519                 return commit_ignore;
3520         if (revs->min_age != -1 &&
3521             comparison_date(revs, commit) > revs->min_age)
3522                         return commit_ignore;
3523         if (revs->min_parents || (revs->max_parents >= 0)) {
3524                 int n = commit_list_count(commit->parents);
3525                 if ((n < revs->min_parents) ||
3526                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
3527                         return commit_ignore;
3528         }
3529         if (!commit_match(commit, revs))
3530                 return commit_ignore;
3531         if (revs->prune && revs->dense) {
3532                 /* Commit without changes? */
3533                 if (commit->object.flags & TREESAME) {
3534                         int n;
3535                         struct commit_list *p;
3536                         /* drop merges unless we want parenthood */
3537                         if (!want_ancestry(revs))
3538                                 return commit_ignore;
3539                         /*
3540                          * If we want ancestry, then need to keep any merges
3541                          * between relevant commits to tie together topology.
3542                          * For consistency with TREESAME and simplification
3543                          * use "relevant" here rather than just INTERESTING,
3544                          * to treat bottom commit(s) as part of the topology.
3545                          */
3546                         for (n = 0, p = commit->parents; p; p = p->next)
3547                                 if (relevant_commit(p->item))
3548                                         if (++n >= 2)
3549                                                 return commit_show;
3550                         return commit_ignore;
3551                 }
3552         }
3553         return commit_show;
3554 }
3555
3556 define_commit_slab(saved_parents, struct commit_list *);
3557
3558 #define EMPTY_PARENT_LIST ((struct commit_list *)-1)
3559
3560 /*
3561  * You may only call save_parents() once per commit (this is checked
3562  * for non-root commits).
3563  */
3564 static void save_parents(struct rev_info *revs, struct commit *commit)
3565 {
3566         struct commit_list **pp;
3567
3568         if (!revs->saved_parents_slab) {
3569                 revs->saved_parents_slab = xmalloc(sizeof(struct saved_parents));
3570                 init_saved_parents(revs->saved_parents_slab);
3571         }
3572
3573         pp = saved_parents_at(revs->saved_parents_slab, commit);
3574
3575         /*
3576          * When walking with reflogs, we may visit the same commit
3577          * several times: once for each appearance in the reflog.
3578          *
3579          * In this case, save_parents() will be called multiple times.
3580          * We want to keep only the first set of parents.  We need to
3581          * store a sentinel value for an empty (i.e., NULL) parent
3582          * list to distinguish it from a not-yet-saved list, however.
3583          */
3584         if (*pp)
3585                 return;
3586         if (commit->parents)
3587                 *pp = copy_commit_list(commit->parents);
3588         else
3589                 *pp = EMPTY_PARENT_LIST;
3590 }
3591
3592 static void free_saved_parents(struct rev_info *revs)
3593 {
3594         if (revs->saved_parents_slab)
3595                 clear_saved_parents(revs->saved_parents_slab);
3596 }
3597
3598 struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit)
3599 {
3600         struct commit_list *parents;
3601
3602         if (!revs->saved_parents_slab)
3603                 return commit->parents;
3604
3605         parents = *saved_parents_at(revs->saved_parents_slab, commit);
3606         if (parents == EMPTY_PARENT_LIST)
3607                 return NULL;
3608         return parents;
3609 }
3610
3611 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
3612 {
3613         enum commit_action action = get_commit_action(revs, commit);
3614
3615         if (action == commit_show &&
3616             revs->prune && revs->dense && want_ancestry(revs)) {
3617                 /*
3618                  * --full-diff on simplified parents is no good: it
3619                  * will show spurious changes from the commits that
3620                  * were elided.  So we save the parents on the side
3621                  * when --full-diff is in effect.
3622                  */
3623                 if (revs->full_diff)
3624                         save_parents(revs, commit);
3625                 if (rewrite_parents(revs, commit, rewrite_one) < 0)
3626                         return commit_error;
3627         }
3628         return action;
3629 }
3630
3631 static void track_linear(struct rev_info *revs, struct commit *commit)
3632 {
3633         if (revs->track_first_time) {
3634                 revs->linear = 1;
3635                 revs->track_first_time = 0;
3636         } else {
3637                 struct commit_list *p;
3638                 for (p = revs->previous_parents; p; p = p->next)
3639                         if (p->item == NULL || /* first commit */
3640                             oideq(&p->item->object.oid, &commit->object.oid))
3641                                 break;
3642                 revs->linear = p != NULL;
3643         }
3644         if (revs->reverse) {
3645                 if (revs->linear)
3646                         commit->object.flags |= TRACK_LINEAR;
3647         }
3648         free_commit_list(revs->previous_parents);
3649         revs->previous_parents = copy_commit_list(commit->parents);
3650 }
3651
3652 static struct commit *get_revision_1(struct rev_info *revs)
3653 {
3654         while (1) {
3655                 struct commit *commit;
3656
3657                 if (revs->reflog_info)
3658                         commit = next_reflog_entry(revs->reflog_info);
3659                 else if (revs->topo_walk_info)
3660                         commit = next_topo_commit(revs);
3661                 else
3662                         commit = pop_commit(&revs->commits);
3663
3664                 if (!commit)
3665                         return NULL;
3666
3667                 if (revs->reflog_info)
3668                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
3669
3670                 /*
3671                  * If we haven't done the list limiting, we need to look at
3672                  * the parents here. We also need to do the date-based limiting
3673                  * that we'd otherwise have done in limit_list().
3674                  */
3675                 if (!revs->limited) {
3676                         if (revs->max_age != -1 &&
3677                             comparison_date(revs, commit) < revs->max_age)
3678                                 continue;
3679
3680                         if (revs->reflog_info)
3681                                 try_to_simplify_commit(revs, commit);
3682                         else if (revs->topo_walk_info)
3683                                 expand_topo_walk(revs, commit);
3684                         else if (process_parents(revs, commit, &revs->commits, NULL) < 0) {
3685                                 if (!revs->ignore_missing_links)
3686                                         die("Failed to traverse parents of commit %s",
3687                                                 oid_to_hex(&commit->object.oid));
3688                         }
3689                 }
3690
3691                 switch (simplify_commit(revs, commit)) {
3692                 case commit_ignore:
3693                         continue;
3694                 case commit_error:
3695                         die("Failed to simplify parents of commit %s",
3696                             oid_to_hex(&commit->object.oid));
3697                 default:
3698                         if (revs->track_linear)
3699                                 track_linear(revs, commit);
3700                         return commit;
3701                 }
3702         }
3703 }
3704
3705 /*
3706  * Return true for entries that have not yet been shown.  (This is an
3707  * object_array_each_func_t.)
3708  */
3709 static int entry_unshown(struct object_array_entry *entry, void *cb_data_unused)
3710 {
3711         return !(entry->item->flags & SHOWN);
3712 }
3713
3714 /*
3715  * If array is on the verge of a realloc, garbage-collect any entries
3716  * that have already been shown to try to free up some space.
3717  */
3718 static void gc_boundary(struct object_array *array)
3719 {
3720         if (array->nr == array->alloc)
3721                 object_array_filter(array, entry_unshown, NULL);
3722 }
3723
3724 static void create_boundary_commit_list(struct rev_info *revs)
3725 {
3726         unsigned i;
3727         struct commit *c;
3728         struct object_array *array = &revs->boundary_commits;
3729         struct object_array_entry *objects = array->objects;
3730
3731         /*
3732          * If revs->commits is non-NULL at this point, an error occurred in
3733          * get_revision_1().  Ignore the error and continue printing the
3734          * boundary commits anyway.  (This is what the code has always
3735          * done.)
3736          */
3737         if (revs->commits) {
3738                 free_commit_list(revs->commits);
3739                 revs->commits = NULL;
3740         }
3741
3742         /*
3743          * Put all of the actual boundary commits from revs->boundary_commits
3744          * into revs->commits
3745          */
3746         for (i = 0; i < array->nr; i++) {
3747                 c = (struct commit *)(objects[i].item);
3748                 if (!c)
3749                         continue;
3750                 if (!(c->object.flags & CHILD_SHOWN))
3751                         continue;
3752                 if (c->object.flags & (SHOWN | BOUNDARY))
3753                         continue;
3754                 c->object.flags |= BOUNDARY;
3755                 commit_list_insert(c, &revs->commits);
3756         }
3757
3758         /*
3759          * If revs->topo_order is set, sort the boundary commits
3760          * in topological order
3761          */
3762         sort_in_topological_order(&revs->commits, revs->sort_order);
3763 }
3764
3765 static struct commit *get_revision_internal(struct rev_info *revs)
3766 {
3767         struct commit *c = NULL;
3768         struct commit_list *l;
3769
3770         if (revs->boundary == 2) {
3771                 /*
3772                  * All of the normal commits have already been returned,
3773                  * and we are now returning boundary commits.
3774                  * create_boundary_commit_list() has populated
3775                  * revs->commits with the remaining commits to return.
3776                  */
3777                 c = pop_commit(&revs->commits);
3778                 if (c)
3779                         c->object.flags |= SHOWN;
3780                 return c;
3781         }
3782
3783         /*
3784          * If our max_count counter has reached zero, then we are done. We
3785          * don't simply return NULL because we still might need to show
3786          * boundary commits. But we want to avoid calling get_revision_1, which
3787          * might do a considerable amount of work finding the next commit only
3788          * for us to throw it away.
3789          *
3790          * If it is non-zero, then either we don't have a max_count at all
3791          * (-1), or it is still counting, in which case we decrement.
3792          */
3793         if (revs->max_count) {
3794                 c = get_revision_1(revs);
3795                 if (c) {
3796                         while (revs->skip_count > 0) {
3797                                 revs->skip_count--;
3798                                 c = get_revision_1(revs);
3799                                 if (!c)
3800                                         break;
3801                         }
3802                 }
3803
3804                 if (revs->max_count > 0)
3805                         revs->max_count--;
3806         }
3807
3808         if (c)
3809                 c->object.flags |= SHOWN;
3810
3811         if (!revs->boundary)
3812                 return c;
3813
3814         if (!c) {
3815                 /*
3816                  * get_revision_1() runs out the commits, and
3817                  * we are done computing the boundaries.
3818                  * switch to boundary commits output mode.
3819                  */
3820                 revs->boundary = 2;
3821
3822                 /*
3823                  * Update revs->commits to contain the list of
3824                  * boundary commits.
3825                  */
3826                 create_boundary_commit_list(revs);
3827
3828                 return get_revision_internal(revs);
3829         }
3830
3831         /*
3832          * boundary commits are the commits that are parents of the
3833          * ones we got from get_revision_1() but they themselves are
3834          * not returned from get_revision_1().  Before returning
3835          * 'c', we need to mark its parents that they could be boundaries.
3836          */
3837
3838         for (l = c->parents; l; l = l->next) {
3839                 struct object *p;
3840                 p = &(l->item->object);
3841                 if (p->flags & (CHILD_SHOWN | SHOWN))
3842                         continue;
3843                 p->flags |= CHILD_SHOWN;
3844                 gc_boundary(&revs->boundary_commits);
3845                 add_object_array(p, NULL, &revs->boundary_commits);
3846         }
3847
3848         return c;
3849 }
3850
3851 struct commit *get_revision(struct rev_info *revs)
3852 {
3853         struct commit *c;
3854         struct commit_list *reversed;
3855
3856         if (revs->reverse) {
3857                 reversed = NULL;
3858                 while ((c = get_revision_internal(revs)))
3859                         commit_list_insert(c, &reversed);
3860                 revs->commits = reversed;
3861                 revs->reverse = 0;
3862                 revs->reverse_output_stage = 1;
3863         }
3864
3865         if (revs->reverse_output_stage) {
3866                 c = pop_commit(&revs->commits);
3867                 if (revs->track_linear)
3868                         revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
3869                 return c;
3870         }
3871
3872         c = get_revision_internal(revs);
3873         if (c && revs->graph)
3874                 graph_update(revs->graph, c);
3875         if (!c) {
3876                 free_saved_parents(revs);
3877                 if (revs->previous_parents) {
3878                         free_commit_list(revs->previous_parents);
3879                         revs->previous_parents = NULL;
3880                 }
3881         }
3882         return c;
3883 }
3884
3885 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
3886 {
3887         if (commit->object.flags & BOUNDARY)
3888                 return "-";
3889         else if (commit->object.flags & UNINTERESTING)
3890                 return "^";
3891         else if (commit->object.flags & PATCHSAME)
3892                 return "=";
3893         else if (!revs || revs->left_right) {
3894                 if (commit->object.flags & SYMMETRIC_LEFT)
3895                         return "<";
3896                 else
3897                         return ">";
3898         } else if (revs->graph)
3899                 return "*";
3900         else if (revs->cherry_mark)
3901                 return "+";
3902         return "";
3903 }
3904
3905 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
3906 {
3907         char *mark = get_revision_mark(revs, commit);
3908         if (!strlen(mark))
3909                 return;
3910         fputs(mark, stdout);
3911         putchar(' ');
3912 }