Merge branch 'maint-2.7' into maint
[git] / revision.c
1 #include "cache.h"
2 #include "tag.h"
3 #include "blob.h"
4 #include "tree.h"
5 #include "commit.h"
6 #include "diff.h"
7 #include "refs.h"
8 #include "revision.h"
9 #include "graph.h"
10 #include "grep.h"
11 #include "reflog-walk.h"
12 #include "patch-ids.h"
13 #include "decorate.h"
14 #include "log-tree.h"
15 #include "string-list.h"
16 #include "line-log.h"
17 #include "mailmap.h"
18 #include "commit-slab.h"
19 #include "dir.h"
20 #include "cache-tree.h"
21 #include "bisect.h"
22
23 volatile show_early_output_fn_t show_early_output;
24
25 static const char *term_bad;
26 static const char *term_good;
27
28 void show_object_with_name(FILE *out, struct object *obj, const char *name)
29 {
30         const char *p;
31
32         fprintf(out, "%s ", oid_to_hex(&obj->oid));
33         for (p = name; *p && *p != '\n'; p++)
34                 fputc(*p, out);
35         fputc('\n', out);
36 }
37
38 static void mark_blob_uninteresting(struct blob *blob)
39 {
40         if (!blob)
41                 return;
42         if (blob->object.flags & UNINTERESTING)
43                 return;
44         blob->object.flags |= UNINTERESTING;
45 }
46
47 static void mark_tree_contents_uninteresting(struct tree *tree)
48 {
49         struct tree_desc desc;
50         struct name_entry entry;
51         struct object *obj = &tree->object;
52
53         if (!has_object_file(&obj->oid))
54                 return;
55         if (parse_tree(tree) < 0)
56                 die("bad tree %s", oid_to_hex(&obj->oid));
57
58         init_tree_desc(&desc, tree->buffer, tree->size);
59         while (tree_entry(&desc, &entry)) {
60                 switch (object_type(entry.mode)) {
61                 case OBJ_TREE:
62                         mark_tree_uninteresting(lookup_tree(entry.sha1));
63                         break;
64                 case OBJ_BLOB:
65                         mark_blob_uninteresting(lookup_blob(entry.sha1));
66                         break;
67                 default:
68                         /* Subproject commit - not in this repository */
69                         break;
70                 }
71         }
72
73         /*
74          * We don't care about the tree any more
75          * after it has been marked uninteresting.
76          */
77         free_tree_buffer(tree);
78 }
79
80 void mark_tree_uninteresting(struct tree *tree)
81 {
82         struct object *obj;
83
84         if (!tree)
85                 return;
86
87         obj = &tree->object;
88         if (obj->flags & UNINTERESTING)
89                 return;
90         obj->flags |= UNINTERESTING;
91         mark_tree_contents_uninteresting(tree);
92 }
93
94 void mark_parents_uninteresting(struct commit *commit)
95 {
96         struct commit_list *parents = NULL, *l;
97
98         for (l = commit->parents; l; l = l->next)
99                 commit_list_insert(l->item, &parents);
100
101         while (parents) {
102                 struct commit *commit = pop_commit(&parents);
103
104                 while (commit) {
105                         /*
106                          * A missing commit is ok iff its parent is marked
107                          * uninteresting.
108                          *
109                          * We just mark such a thing parsed, so that when
110                          * it is popped next time around, we won't be trying
111                          * to parse it and get an error.
112                          */
113                         if (!has_object_file(&commit->object.oid))
114                                 commit->object.parsed = 1;
115
116                         if (commit->object.flags & UNINTERESTING)
117                                 break;
118
119                         commit->object.flags |= UNINTERESTING;
120
121                         /*
122                          * Normally we haven't parsed the parent
123                          * yet, so we won't have a parent of a parent
124                          * here. However, it may turn out that we've
125                          * reached this commit some other way (where it
126                          * wasn't uninteresting), in which case we need
127                          * to mark its parents recursively too..
128                          */
129                         if (!commit->parents)
130                                 break;
131
132                         for (l = commit->parents->next; l; l = l->next)
133                                 commit_list_insert(l->item, &parents);
134                         commit = commit->parents->item;
135                 }
136         }
137 }
138
139 static void add_pending_object_with_path(struct rev_info *revs,
140                                          struct object *obj,
141                                          const char *name, unsigned mode,
142                                          const char *path)
143 {
144         if (!obj)
145                 return;
146         if (revs->no_walk && (obj->flags & UNINTERESTING))
147                 revs->no_walk = 0;
148         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
149                 struct strbuf buf = STRBUF_INIT;
150                 int len = interpret_branch_name(name, 0, &buf);
151                 int st;
152
153                 if (0 < len && name[len] && buf.len)
154                         strbuf_addstr(&buf, name + len);
155                 st = add_reflog_for_walk(revs->reflog_info,
156                                          (struct commit *)obj,
157                                          buf.buf[0] ? buf.buf: name);
158                 strbuf_release(&buf);
159                 if (st)
160                         return;
161         }
162         add_object_array_with_path(obj, name, &revs->pending, mode, path);
163 }
164
165 static void add_pending_object_with_mode(struct rev_info *revs,
166                                          struct object *obj,
167                                          const char *name, unsigned mode)
168 {
169         add_pending_object_with_path(revs, obj, name, mode, NULL);
170 }
171
172 void add_pending_object(struct rev_info *revs,
173                         struct object *obj, const char *name)
174 {
175         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
176 }
177
178 void add_head_to_pending(struct rev_info *revs)
179 {
180         unsigned char sha1[20];
181         struct object *obj;
182         if (get_sha1("HEAD", sha1))
183                 return;
184         obj = parse_object(sha1);
185         if (!obj)
186                 return;
187         add_pending_object(revs, obj, "HEAD");
188 }
189
190 static struct object *get_reference(struct rev_info *revs, const char *name,
191                                     const unsigned char *sha1,
192                                     unsigned int flags)
193 {
194         struct object *object;
195
196         object = parse_object(sha1);
197         if (!object) {
198                 if (revs->ignore_missing)
199                         return object;
200                 die("bad object %s", name);
201         }
202         object->flags |= flags;
203         return object;
204 }
205
206 void add_pending_sha1(struct rev_info *revs, const char *name,
207                       const unsigned char *sha1, unsigned int flags)
208 {
209         struct object *object = get_reference(revs, name, sha1, flags);
210         add_pending_object(revs, object, name);
211 }
212
213 static struct commit *handle_commit(struct rev_info *revs,
214                                     struct object_array_entry *entry)
215 {
216         struct object *object = entry->item;
217         const char *name = entry->name;
218         const char *path = entry->path;
219         unsigned int mode = entry->mode;
220         unsigned long flags = object->flags;
221
222         /*
223          * Tag object? Look what it points to..
224          */
225         while (object->type == OBJ_TAG) {
226                 struct tag *tag = (struct tag *) object;
227                 if (revs->tag_objects && !(flags & UNINTERESTING))
228                         add_pending_object(revs, object, tag->tag);
229                 if (!tag->tagged)
230                         die("bad tag");
231                 object = parse_object(tag->tagged->oid.hash);
232                 if (!object) {
233                         if (flags & UNINTERESTING)
234                                 return NULL;
235                         die("bad object %s", oid_to_hex(&tag->tagged->oid));
236                 }
237                 object->flags |= flags;
238                 /*
239                  * We'll handle the tagged object by looping or dropping
240                  * through to the non-tag handlers below. Do not
241                  * propagate path data from the tag's pending entry.
242                  */
243                 path = NULL;
244                 mode = 0;
245         }
246
247         /*
248          * Commit object? Just return it, we'll do all the complex
249          * reachability crud.
250          */
251         if (object->type == OBJ_COMMIT) {
252                 struct commit *commit = (struct commit *)object;
253                 if (parse_commit(commit) < 0)
254                         die("unable to parse commit %s", name);
255                 if (flags & UNINTERESTING) {
256                         mark_parents_uninteresting(commit);
257                         revs->limited = 1;
258                 }
259                 if (revs->show_source && !commit->util)
260                         commit->util = xstrdup(name);
261                 return commit;
262         }
263
264         /*
265          * Tree object? Either mark it uninteresting, or add it
266          * to the list of objects to look at later..
267          */
268         if (object->type == OBJ_TREE) {
269                 struct tree *tree = (struct tree *)object;
270                 if (!revs->tree_objects)
271                         return NULL;
272                 if (flags & UNINTERESTING) {
273                         mark_tree_contents_uninteresting(tree);
274                         return NULL;
275                 }
276                 add_pending_object_with_path(revs, object, name, mode, path);
277                 return NULL;
278         }
279
280         /*
281          * Blob object? You know the drill by now..
282          */
283         if (object->type == OBJ_BLOB) {
284                 if (!revs->blob_objects)
285                         return NULL;
286                 if (flags & UNINTERESTING)
287                         return NULL;
288                 add_pending_object_with_path(revs, object, name, mode, path);
289                 return NULL;
290         }
291         die("%s is unknown object", name);
292 }
293
294 static int everybody_uninteresting(struct commit_list *orig,
295                                    struct commit **interesting_cache)
296 {
297         struct commit_list *list = orig;
298
299         if (*interesting_cache) {
300                 struct commit *commit = *interesting_cache;
301                 if (!(commit->object.flags & UNINTERESTING))
302                         return 0;
303         }
304
305         while (list) {
306                 struct commit *commit = list->item;
307                 list = list->next;
308                 if (commit->object.flags & UNINTERESTING)
309                         continue;
310
311                 *interesting_cache = commit;
312                 return 0;
313         }
314         return 1;
315 }
316
317 /*
318  * A definition of "relevant" commit that we can use to simplify limited graphs
319  * by eliminating side branches.
320  *
321  * A "relevant" commit is one that is !UNINTERESTING (ie we are including it
322  * in our list), or that is a specified BOTTOM commit. Then after computing
323  * a limited list, during processing we can generally ignore boundary merges
324  * coming from outside the graph, (ie from irrelevant parents), and treat
325  * those merges as if they were single-parent. TREESAME is defined to consider
326  * only relevant parents, if any. If we are TREESAME to our on-graph parents,
327  * we don't care if we were !TREESAME to non-graph parents.
328  *
329  * Treating bottom commits as relevant ensures that a limited graph's
330  * connection to the actual bottom commit is not viewed as a side branch, but
331  * treated as part of the graph. For example:
332  *
333  *   ....Z...A---X---o---o---B
334  *        .     /
335  *         W---Y
336  *
337  * When computing "A..B", the A-X connection is at least as important as
338  * Y-X, despite A being flagged UNINTERESTING.
339  *
340  * And when computing --ancestry-path "A..B", the A-X connection is more
341  * important than Y-X, despite both A and Y being flagged UNINTERESTING.
342  */
343 static inline int relevant_commit(struct commit *commit)
344 {
345         return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
346 }
347
348 /*
349  * Return a single relevant commit from a parent list. If we are a TREESAME
350  * commit, and this selects one of our parents, then we can safely simplify to
351  * that parent.
352  */
353 static struct commit *one_relevant_parent(const struct rev_info *revs,
354                                           struct commit_list *orig)
355 {
356         struct commit_list *list = orig;
357         struct commit *relevant = NULL;
358
359         if (!orig)
360                 return NULL;
361
362         /*
363          * For 1-parent commits, or if first-parent-only, then return that
364          * first parent (even if not "relevant" by the above definition).
365          * TREESAME will have been set purely on that parent.
366          */
367         if (revs->first_parent_only || !orig->next)
368                 return orig->item;
369
370         /*
371          * For multi-parent commits, identify a sole relevant parent, if any.
372          * If we have only one relevant parent, then TREESAME will be set purely
373          * with regard to that parent, and we can simplify accordingly.
374          *
375          * If we have more than one relevant parent, or no relevant parents
376          * (and multiple irrelevant ones), then we can't select a parent here
377          * and return NULL.
378          */
379         while (list) {
380                 struct commit *commit = list->item;
381                 list = list->next;
382                 if (relevant_commit(commit)) {
383                         if (relevant)
384                                 return NULL;
385                         relevant = commit;
386                 }
387         }
388         return relevant;
389 }
390
391 /*
392  * The goal is to get REV_TREE_NEW as the result only if the
393  * diff consists of all '+' (and no other changes), REV_TREE_OLD
394  * if the whole diff is removal of old data, and otherwise
395  * REV_TREE_DIFFERENT (of course if the trees are the same we
396  * want REV_TREE_SAME).
397  * That means that once we get to REV_TREE_DIFFERENT, we do not
398  * have to look any further.
399  */
400 static int tree_difference = REV_TREE_SAME;
401
402 static void file_add_remove(struct diff_options *options,
403                     int addremove, unsigned mode,
404                     const unsigned char *sha1,
405                     int sha1_valid,
406                     const char *fullpath, unsigned dirty_submodule)
407 {
408         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
409
410         tree_difference |= diff;
411         if (tree_difference == REV_TREE_DIFFERENT)
412                 DIFF_OPT_SET(options, HAS_CHANGES);
413 }
414
415 static void file_change(struct diff_options *options,
416                  unsigned old_mode, unsigned new_mode,
417                  const unsigned char *old_sha1,
418                  const unsigned char *new_sha1,
419                  int old_sha1_valid, int new_sha1_valid,
420                  const char *fullpath,
421                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
422 {
423         tree_difference = REV_TREE_DIFFERENT;
424         DIFF_OPT_SET(options, HAS_CHANGES);
425 }
426
427 static int rev_compare_tree(struct rev_info *revs,
428                             struct commit *parent, struct commit *commit)
429 {
430         struct tree *t1 = parent->tree;
431         struct tree *t2 = commit->tree;
432
433         if (!t1)
434                 return REV_TREE_NEW;
435         if (!t2)
436                 return REV_TREE_OLD;
437
438         if (revs->simplify_by_decoration) {
439                 /*
440                  * If we are simplifying by decoration, then the commit
441                  * is worth showing if it has a tag pointing at it.
442                  */
443                 if (get_name_decoration(&commit->object))
444                         return REV_TREE_DIFFERENT;
445                 /*
446                  * A commit that is not pointed by a tag is uninteresting
447                  * if we are not limited by path.  This means that you will
448                  * see the usual "commits that touch the paths" plus any
449                  * tagged commit by specifying both --simplify-by-decoration
450                  * and pathspec.
451                  */
452                 if (!revs->prune_data.nr)
453                         return REV_TREE_SAME;
454         }
455
456         tree_difference = REV_TREE_SAME;
457         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
458         if (diff_tree_sha1(t1->object.oid.hash, t2->object.oid.hash, "",
459                            &revs->pruning) < 0)
460                 return REV_TREE_DIFFERENT;
461         return tree_difference;
462 }
463
464 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
465 {
466         int retval;
467         struct tree *t1 = commit->tree;
468
469         if (!t1)
470                 return 0;
471
472         tree_difference = REV_TREE_SAME;
473         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
474         retval = diff_tree_sha1(NULL, t1->object.oid.hash, "", &revs->pruning);
475
476         return retval >= 0 && (tree_difference == REV_TREE_SAME);
477 }
478
479 struct treesame_state {
480         unsigned int nparents;
481         unsigned char treesame[FLEX_ARRAY];
482 };
483
484 static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
485 {
486         unsigned n = commit_list_count(commit->parents);
487         struct treesame_state *st = xcalloc(1, st_add(sizeof(*st), n));
488         st->nparents = n;
489         add_decoration(&revs->treesame, &commit->object, st);
490         return st;
491 }
492
493 /*
494  * Must be called immediately after removing the nth_parent from a commit's
495  * parent list, if we are maintaining the per-parent treesame[] decoration.
496  * This does not recalculate the master TREESAME flag - update_treesame()
497  * should be called to update it after a sequence of treesame[] modifications
498  * that may have affected it.
499  */
500 static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
501 {
502         struct treesame_state *st;
503         int old_same;
504
505         if (!commit->parents) {
506                 /*
507                  * Have just removed the only parent from a non-merge.
508                  * Different handling, as we lack decoration.
509                  */
510                 if (nth_parent != 0)
511                         die("compact_treesame %u", nth_parent);
512                 old_same = !!(commit->object.flags & TREESAME);
513                 if (rev_same_tree_as_empty(revs, commit))
514                         commit->object.flags |= TREESAME;
515                 else
516                         commit->object.flags &= ~TREESAME;
517                 return old_same;
518         }
519
520         st = lookup_decoration(&revs->treesame, &commit->object);
521         if (!st || nth_parent >= st->nparents)
522                 die("compact_treesame %u", nth_parent);
523
524         old_same = st->treesame[nth_parent];
525         memmove(st->treesame + nth_parent,
526                 st->treesame + nth_parent + 1,
527                 st->nparents - nth_parent - 1);
528
529         /*
530          * If we've just become a non-merge commit, update TREESAME
531          * immediately, and remove the no-longer-needed decoration.
532          * If still a merge, defer update until update_treesame().
533          */
534         if (--st->nparents == 1) {
535                 if (commit->parents->next)
536                         die("compact_treesame parents mismatch");
537                 if (st->treesame[0] && revs->dense)
538                         commit->object.flags |= TREESAME;
539                 else
540                         commit->object.flags &= ~TREESAME;
541                 free(add_decoration(&revs->treesame, &commit->object, NULL));
542         }
543
544         return old_same;
545 }
546
547 static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
548 {
549         if (commit->parents && commit->parents->next) {
550                 unsigned n;
551                 struct treesame_state *st;
552                 struct commit_list *p;
553                 unsigned relevant_parents;
554                 unsigned relevant_change, irrelevant_change;
555
556                 st = lookup_decoration(&revs->treesame, &commit->object);
557                 if (!st)
558                         die("update_treesame %s", oid_to_hex(&commit->object.oid));
559                 relevant_parents = 0;
560                 relevant_change = irrelevant_change = 0;
561                 for (p = commit->parents, n = 0; p; n++, p = p->next) {
562                         if (relevant_commit(p->item)) {
563                                 relevant_change |= !st->treesame[n];
564                                 relevant_parents++;
565                         } else
566                                 irrelevant_change |= !st->treesame[n];
567                 }
568                 if (relevant_parents ? relevant_change : irrelevant_change)
569                         commit->object.flags &= ~TREESAME;
570                 else
571                         commit->object.flags |= TREESAME;
572         }
573
574         return commit->object.flags & TREESAME;
575 }
576
577 static inline int limiting_can_increase_treesame(const struct rev_info *revs)
578 {
579         /*
580          * TREESAME is irrelevant unless prune && dense;
581          * if simplify_history is set, we can't have a mixture of TREESAME and
582          *    !TREESAME INTERESTING parents (and we don't have treesame[]
583          *    decoration anyway);
584          * if first_parent_only is set, then the TREESAME flag is locked
585          *    against the first parent (and again we lack treesame[] decoration).
586          */
587         return revs->prune && revs->dense &&
588                !revs->simplify_history &&
589                !revs->first_parent_only;
590 }
591
592 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
593 {
594         struct commit_list **pp, *parent;
595         struct treesame_state *ts = NULL;
596         int relevant_change = 0, irrelevant_change = 0;
597         int relevant_parents, nth_parent;
598
599         /*
600          * If we don't do pruning, everything is interesting
601          */
602         if (!revs->prune)
603                 return;
604
605         if (!commit->tree)
606                 return;
607
608         if (!commit->parents) {
609                 if (rev_same_tree_as_empty(revs, commit))
610                         commit->object.flags |= TREESAME;
611                 return;
612         }
613
614         /*
615          * Normal non-merge commit? If we don't want to make the
616          * history dense, we consider it always to be a change..
617          */
618         if (!revs->dense && !commit->parents->next)
619                 return;
620
621         for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
622              (parent = *pp) != NULL;
623              pp = &parent->next, nth_parent++) {
624                 struct commit *p = parent->item;
625                 if (relevant_commit(p))
626                         relevant_parents++;
627
628                 if (nth_parent == 1) {
629                         /*
630                          * This our second loop iteration - so we now know
631                          * we're dealing with a merge.
632                          *
633                          * Do not compare with later parents when we care only about
634                          * the first parent chain, in order to avoid derailing the
635                          * traversal to follow a side branch that brought everything
636                          * in the path we are limited to by the pathspec.
637                          */
638                         if (revs->first_parent_only)
639                                 break;
640                         /*
641                          * If this will remain a potentially-simplifiable
642                          * merge, remember per-parent treesame if needed.
643                          * Initialise the array with the comparison from our
644                          * first iteration.
645                          */
646                         if (revs->treesame.name &&
647                             !revs->simplify_history &&
648                             !(commit->object.flags & UNINTERESTING)) {
649                                 ts = initialise_treesame(revs, commit);
650                                 if (!(irrelevant_change || relevant_change))
651                                         ts->treesame[0] = 1;
652                         }
653                 }
654                 if (parse_commit(p) < 0)
655                         die("cannot simplify commit %s (because of %s)",
656                             oid_to_hex(&commit->object.oid),
657                             oid_to_hex(&p->object.oid));
658                 switch (rev_compare_tree(revs, p, commit)) {
659                 case REV_TREE_SAME:
660                         if (!revs->simplify_history || !relevant_commit(p)) {
661                                 /* Even if a merge with an uninteresting
662                                  * side branch brought the entire change
663                                  * we are interested in, we do not want
664                                  * to lose the other branches of this
665                                  * merge, so we just keep going.
666                                  */
667                                 if (ts)
668                                         ts->treesame[nth_parent] = 1;
669                                 continue;
670                         }
671                         parent->next = NULL;
672                         commit->parents = parent;
673                         commit->object.flags |= TREESAME;
674                         return;
675
676                 case REV_TREE_NEW:
677                         if (revs->remove_empty_trees &&
678                             rev_same_tree_as_empty(revs, p)) {
679                                 /* We are adding all the specified
680                                  * paths from this parent, so the
681                                  * history beyond this parent is not
682                                  * interesting.  Remove its parents
683                                  * (they are grandparents for us).
684                                  * IOW, we pretend this parent is a
685                                  * "root" commit.
686                                  */
687                                 if (parse_commit(p) < 0)
688                                         die("cannot simplify commit %s (invalid %s)",
689                                             oid_to_hex(&commit->object.oid),
690                                             oid_to_hex(&p->object.oid));
691                                 p->parents = NULL;
692                         }
693                 /* fallthrough */
694                 case REV_TREE_OLD:
695                 case REV_TREE_DIFFERENT:
696                         if (relevant_commit(p))
697                                 relevant_change = 1;
698                         else
699                                 irrelevant_change = 1;
700                         continue;
701                 }
702                 die("bad tree compare for commit %s", oid_to_hex(&commit->object.oid));
703         }
704
705         /*
706          * TREESAME is straightforward for single-parent commits. For merge
707          * commits, it is most useful to define it so that "irrelevant"
708          * parents cannot make us !TREESAME - if we have any relevant
709          * parents, then we only consider TREESAMEness with respect to them,
710          * allowing irrelevant merges from uninteresting branches to be
711          * simplified away. Only if we have only irrelevant parents do we
712          * base TREESAME on them. Note that this logic is replicated in
713          * update_treesame, which should be kept in sync.
714          */
715         if (relevant_parents ? !relevant_change : !irrelevant_change)
716                 commit->object.flags |= TREESAME;
717 }
718
719 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
720                     struct commit_list *cached_base, struct commit_list **cache)
721 {
722         struct commit_list *new_entry;
723
724         if (cached_base && p->date < cached_base->item->date)
725                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
726         else
727                 new_entry = commit_list_insert_by_date(p, head);
728
729         if (cache && (!*cache || p->date < (*cache)->item->date))
730                 *cache = new_entry;
731 }
732
733 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
734                     struct commit_list **list, struct commit_list **cache_ptr)
735 {
736         struct commit_list *parent = commit->parents;
737         unsigned left_flag;
738         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
739
740         if (commit->object.flags & ADDED)
741                 return 0;
742         commit->object.flags |= ADDED;
743
744         if (revs->include_check &&
745             !revs->include_check(commit, revs->include_check_data))
746                 return 0;
747
748         /*
749          * If the commit is uninteresting, don't try to
750          * prune parents - we want the maximal uninteresting
751          * set.
752          *
753          * Normally we haven't parsed the parent
754          * yet, so we won't have a parent of a parent
755          * here. However, it may turn out that we've
756          * reached this commit some other way (where it
757          * wasn't uninteresting), in which case we need
758          * to mark its parents recursively too..
759          */
760         if (commit->object.flags & UNINTERESTING) {
761                 while (parent) {
762                         struct commit *p = parent->item;
763                         parent = parent->next;
764                         if (p)
765                                 p->object.flags |= UNINTERESTING;
766                         if (parse_commit_gently(p, 1) < 0)
767                                 continue;
768                         if (p->parents)
769                                 mark_parents_uninteresting(p);
770                         if (p->object.flags & SEEN)
771                                 continue;
772                         p->object.flags |= SEEN;
773                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
774                 }
775                 return 0;
776         }
777
778         /*
779          * Ok, the commit wasn't uninteresting. Try to
780          * simplify the commit history and find the parent
781          * that has no differences in the path set if one exists.
782          */
783         try_to_simplify_commit(revs, commit);
784
785         if (revs->no_walk)
786                 return 0;
787
788         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
789
790         for (parent = commit->parents; parent; parent = parent->next) {
791                 struct commit *p = parent->item;
792
793                 if (parse_commit_gently(p, revs->ignore_missing_links) < 0)
794                         return -1;
795                 if (revs->show_source && !p->util)
796                         p->util = commit->util;
797                 p->object.flags |= left_flag;
798                 if (!(p->object.flags & SEEN)) {
799                         p->object.flags |= SEEN;
800                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
801                 }
802                 if (revs->first_parent_only)
803                         break;
804         }
805         return 0;
806 }
807
808 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
809 {
810         struct commit_list *p;
811         int left_count = 0, right_count = 0;
812         int left_first;
813         struct patch_ids ids;
814         unsigned cherry_flag;
815
816         /* First count the commits on the left and on the right */
817         for (p = list; p; p = p->next) {
818                 struct commit *commit = p->item;
819                 unsigned flags = commit->object.flags;
820                 if (flags & BOUNDARY)
821                         ;
822                 else if (flags & SYMMETRIC_LEFT)
823                         left_count++;
824                 else
825                         right_count++;
826         }
827
828         if (!left_count || !right_count)
829                 return;
830
831         left_first = left_count < right_count;
832         init_patch_ids(&ids);
833         ids.diffopts.pathspec = revs->diffopt.pathspec;
834
835         /* Compute patch-ids for one side */
836         for (p = list; p; p = p->next) {
837                 struct commit *commit = p->item;
838                 unsigned flags = commit->object.flags;
839
840                 if (flags & BOUNDARY)
841                         continue;
842                 /*
843                  * If we have fewer left, left_first is set and we omit
844                  * commits on the right branch in this loop.  If we have
845                  * fewer right, we skip the left ones.
846                  */
847                 if (left_first != !!(flags & SYMMETRIC_LEFT))
848                         continue;
849                 commit->util = add_commit_patch_id(commit, &ids);
850         }
851
852         /* either cherry_mark or cherry_pick are true */
853         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
854
855         /* Check the other side */
856         for (p = list; p; p = p->next) {
857                 struct commit *commit = p->item;
858                 struct patch_id *id;
859                 unsigned flags = commit->object.flags;
860
861                 if (flags & BOUNDARY)
862                         continue;
863                 /*
864                  * If we have fewer left, left_first is set and we omit
865                  * commits on the left branch in this loop.
866                  */
867                 if (left_first == !!(flags & SYMMETRIC_LEFT))
868                         continue;
869
870                 /*
871                  * Have we seen the same patch id?
872                  */
873                 id = has_commit_patch_id(commit, &ids);
874                 if (!id)
875                         continue;
876                 id->seen = 1;
877                 commit->object.flags |= cherry_flag;
878         }
879
880         /* Now check the original side for seen ones */
881         for (p = list; p; p = p->next) {
882                 struct commit *commit = p->item;
883                 struct patch_id *ent;
884
885                 ent = commit->util;
886                 if (!ent)
887                         continue;
888                 if (ent->seen)
889                         commit->object.flags |= cherry_flag;
890                 commit->util = NULL;
891         }
892
893         free_patch_ids(&ids);
894 }
895
896 /* How many extra uninteresting commits we want to see.. */
897 #define SLOP 5
898
899 static int still_interesting(struct commit_list *src, unsigned long date, int slop,
900                              struct commit **interesting_cache)
901 {
902         /*
903          * No source list at all? We're definitely done..
904          */
905         if (!src)
906                 return 0;
907
908         /*
909          * Does the destination list contain entries with a date
910          * before the source list? Definitely _not_ done.
911          */
912         if (date <= src->item->date)
913                 return SLOP;
914
915         /*
916          * Does the source list still have interesting commits in
917          * it? Definitely not done..
918          */
919         if (!everybody_uninteresting(src, interesting_cache))
920                 return SLOP;
921
922         /* Ok, we're closing in.. */
923         return slop-1;
924 }
925
926 /*
927  * "rev-list --ancestry-path A..B" computes commits that are ancestors
928  * of B but not ancestors of A but further limits the result to those
929  * that are descendants of A.  This takes the list of bottom commits and
930  * the result of "A..B" without --ancestry-path, and limits the latter
931  * further to the ones that can reach one of the commits in "bottom".
932  */
933 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
934 {
935         struct commit_list *p;
936         struct commit_list *rlist = NULL;
937         int made_progress;
938
939         /*
940          * Reverse the list so that it will be likely that we would
941          * process parents before children.
942          */
943         for (p = list; p; p = p->next)
944                 commit_list_insert(p->item, &rlist);
945
946         for (p = bottom; p; p = p->next)
947                 p->item->object.flags |= TMP_MARK;
948
949         /*
950          * Mark the ones that can reach bottom commits in "list",
951          * in a bottom-up fashion.
952          */
953         do {
954                 made_progress = 0;
955                 for (p = rlist; p; p = p->next) {
956                         struct commit *c = p->item;
957                         struct commit_list *parents;
958                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
959                                 continue;
960                         for (parents = c->parents;
961                              parents;
962                              parents = parents->next) {
963                                 if (!(parents->item->object.flags & TMP_MARK))
964                                         continue;
965                                 c->object.flags |= TMP_MARK;
966                                 made_progress = 1;
967                                 break;
968                         }
969                 }
970         } while (made_progress);
971
972         /*
973          * NEEDSWORK: decide if we want to remove parents that are
974          * not marked with TMP_MARK from commit->parents for commits
975          * in the resulting list.  We may not want to do that, though.
976          */
977
978         /*
979          * The ones that are not marked with TMP_MARK are uninteresting
980          */
981         for (p = list; p; p = p->next) {
982                 struct commit *c = p->item;
983                 if (c->object.flags & TMP_MARK)
984                         continue;
985                 c->object.flags |= UNINTERESTING;
986         }
987
988         /* We are done with the TMP_MARK */
989         for (p = list; p; p = p->next)
990                 p->item->object.flags &= ~TMP_MARK;
991         for (p = bottom; p; p = p->next)
992                 p->item->object.flags &= ~TMP_MARK;
993         free_commit_list(rlist);
994 }
995
996 /*
997  * Before walking the history, keep the set of "negative" refs the
998  * caller has asked to exclude.
999  *
1000  * This is used to compute "rev-list --ancestry-path A..B", as we need
1001  * to filter the result of "A..B" further to the ones that can actually
1002  * reach A.
1003  */
1004 static struct commit_list *collect_bottom_commits(struct commit_list *list)
1005 {
1006         struct commit_list *elem, *bottom = NULL;
1007         for (elem = list; elem; elem = elem->next)
1008                 if (elem->item->object.flags & BOTTOM)
1009                         commit_list_insert(elem->item, &bottom);
1010         return bottom;
1011 }
1012
1013 /* Assumes either left_only or right_only is set */
1014 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
1015 {
1016         struct commit_list *p;
1017
1018         for (p = list; p; p = p->next) {
1019                 struct commit *commit = p->item;
1020
1021                 if (revs->right_only) {
1022                         if (commit->object.flags & SYMMETRIC_LEFT)
1023                                 commit->object.flags |= SHOWN;
1024                 } else  /* revs->left_only is set */
1025                         if (!(commit->object.flags & SYMMETRIC_LEFT))
1026                                 commit->object.flags |= SHOWN;
1027         }
1028 }
1029
1030 static int limit_list(struct rev_info *revs)
1031 {
1032         int slop = SLOP;
1033         unsigned long date = ~0ul;
1034         struct commit_list *list = revs->commits;
1035         struct commit_list *newlist = NULL;
1036         struct commit_list **p = &newlist;
1037         struct commit_list *bottom = NULL;
1038         struct commit *interesting_cache = NULL;
1039
1040         if (revs->ancestry_path) {
1041                 bottom = collect_bottom_commits(list);
1042                 if (!bottom)
1043                         die("--ancestry-path given but there are no bottom commits");
1044         }
1045
1046         while (list) {
1047                 struct commit *commit = pop_commit(&list);
1048                 struct object *obj = &commit->object;
1049                 show_early_output_fn_t show;
1050
1051                 if (commit == interesting_cache)
1052                         interesting_cache = NULL;
1053
1054                 if (revs->max_age != -1 && (commit->date < revs->max_age))
1055                         obj->flags |= UNINTERESTING;
1056                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
1057                         return -1;
1058                 if (obj->flags & UNINTERESTING) {
1059                         mark_parents_uninteresting(commit);
1060                         if (revs->show_all)
1061                                 p = &commit_list_insert(commit, p)->next;
1062                         slop = still_interesting(list, date, slop, &interesting_cache);
1063                         if (slop)
1064                                 continue;
1065                         /* If showing all, add the whole pending list to the end */
1066                         if (revs->show_all)
1067                                 *p = list;
1068                         break;
1069                 }
1070                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1071                         continue;
1072                 date = commit->date;
1073                 p = &commit_list_insert(commit, p)->next;
1074
1075                 show = show_early_output;
1076                 if (!show)
1077                         continue;
1078
1079                 show(revs, newlist);
1080                 show_early_output = NULL;
1081         }
1082         if (revs->cherry_pick || revs->cherry_mark)
1083                 cherry_pick_list(newlist, revs);
1084
1085         if (revs->left_only || revs->right_only)
1086                 limit_left_right(newlist, revs);
1087
1088         if (bottom) {
1089                 limit_to_ancestry(bottom, newlist);
1090                 free_commit_list(bottom);
1091         }
1092
1093         /*
1094          * Check if any commits have become TREESAME by some of their parents
1095          * becoming UNINTERESTING.
1096          */
1097         if (limiting_can_increase_treesame(revs))
1098                 for (list = newlist; list; list = list->next) {
1099                         struct commit *c = list->item;
1100                         if (c->object.flags & (UNINTERESTING | TREESAME))
1101                                 continue;
1102                         update_treesame(revs, c);
1103                 }
1104
1105         revs->commits = newlist;
1106         return 0;
1107 }
1108
1109 /*
1110  * Add an entry to refs->cmdline with the specified information.
1111  * *name is copied.
1112  */
1113 static void add_rev_cmdline(struct rev_info *revs,
1114                             struct object *item,
1115                             const char *name,
1116                             int whence,
1117                             unsigned flags)
1118 {
1119         struct rev_cmdline_info *info = &revs->cmdline;
1120         int nr = info->nr;
1121
1122         ALLOC_GROW(info->rev, nr + 1, info->alloc);
1123         info->rev[nr].item = item;
1124         info->rev[nr].name = xstrdup(name);
1125         info->rev[nr].whence = whence;
1126         info->rev[nr].flags = flags;
1127         info->nr++;
1128 }
1129
1130 static void add_rev_cmdline_list(struct rev_info *revs,
1131                                  struct commit_list *commit_list,
1132                                  int whence,
1133                                  unsigned flags)
1134 {
1135         while (commit_list) {
1136                 struct object *object = &commit_list->item->object;
1137                 add_rev_cmdline(revs, object, oid_to_hex(&object->oid),
1138                                 whence, flags);
1139                 commit_list = commit_list->next;
1140         }
1141 }
1142
1143 struct all_refs_cb {
1144         int all_flags;
1145         int warned_bad_reflog;
1146         struct rev_info *all_revs;
1147         const char *name_for_errormsg;
1148 };
1149
1150 int ref_excluded(struct string_list *ref_excludes, const char *path)
1151 {
1152         struct string_list_item *item;
1153
1154         if (!ref_excludes)
1155                 return 0;
1156         for_each_string_list_item(item, ref_excludes) {
1157                 if (!wildmatch(item->string, path, 0, NULL))
1158                         return 1;
1159         }
1160         return 0;
1161 }
1162
1163 static int handle_one_ref(const char *path, const struct object_id *oid,
1164                           int flag, void *cb_data)
1165 {
1166         struct all_refs_cb *cb = cb_data;
1167         struct object *object;
1168
1169         if (ref_excluded(cb->all_revs->ref_excludes, path))
1170             return 0;
1171
1172         object = get_reference(cb->all_revs, path, oid->hash, cb->all_flags);
1173         add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
1174         add_pending_sha1(cb->all_revs, path, oid->hash, cb->all_flags);
1175         return 0;
1176 }
1177
1178 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
1179         unsigned flags)
1180 {
1181         cb->all_revs = revs;
1182         cb->all_flags = flags;
1183 }
1184
1185 void clear_ref_exclusion(struct string_list **ref_excludes_p)
1186 {
1187         if (*ref_excludes_p) {
1188                 string_list_clear(*ref_excludes_p, 0);
1189                 free(*ref_excludes_p);
1190         }
1191         *ref_excludes_p = NULL;
1192 }
1193
1194 void add_ref_exclusion(struct string_list **ref_excludes_p, const char *exclude)
1195 {
1196         if (!*ref_excludes_p) {
1197                 *ref_excludes_p = xcalloc(1, sizeof(**ref_excludes_p));
1198                 (*ref_excludes_p)->strdup_strings = 1;
1199         }
1200         string_list_append(*ref_excludes_p, exclude);
1201 }
1202
1203 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
1204                 int (*for_each)(const char *, each_ref_fn, void *))
1205 {
1206         struct all_refs_cb cb;
1207         init_all_refs_cb(&cb, revs, flags);
1208         for_each(submodule, handle_one_ref, &cb);
1209 }
1210
1211 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
1212 {
1213         struct all_refs_cb *cb = cb_data;
1214         if (!is_null_sha1(sha1)) {
1215                 struct object *o = parse_object(sha1);
1216                 if (o) {
1217                         o->flags |= cb->all_flags;
1218                         /* ??? CMDLINEFLAGS ??? */
1219                         add_pending_object(cb->all_revs, o, "");
1220                 }
1221                 else if (!cb->warned_bad_reflog) {
1222                         warning("reflog of '%s' references pruned commits",
1223                                 cb->name_for_errormsg);
1224                         cb->warned_bad_reflog = 1;
1225                 }
1226         }
1227 }
1228
1229 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
1230                 const char *email, unsigned long timestamp, int tz,
1231                 const char *message, void *cb_data)
1232 {
1233         handle_one_reflog_commit(osha1, cb_data);
1234         handle_one_reflog_commit(nsha1, cb_data);
1235         return 0;
1236 }
1237
1238 static int handle_one_reflog(const char *path, const struct object_id *oid,
1239                              int flag, void *cb_data)
1240 {
1241         struct all_refs_cb *cb = cb_data;
1242         cb->warned_bad_reflog = 0;
1243         cb->name_for_errormsg = path;
1244         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
1245         return 0;
1246 }
1247
1248 void add_reflogs_to_pending(struct rev_info *revs, unsigned flags)
1249 {
1250         struct all_refs_cb cb;
1251
1252         cb.all_revs = revs;
1253         cb.all_flags = flags;
1254         for_each_reflog(handle_one_reflog, &cb);
1255 }
1256
1257 static void add_cache_tree(struct cache_tree *it, struct rev_info *revs,
1258                            struct strbuf *path)
1259 {
1260         size_t baselen = path->len;
1261         int i;
1262
1263         if (it->entry_count >= 0) {
1264                 struct tree *tree = lookup_tree(it->sha1);
1265                 add_pending_object_with_path(revs, &tree->object, "",
1266                                              040000, path->buf);
1267         }
1268
1269         for (i = 0; i < it->subtree_nr; i++) {
1270                 struct cache_tree_sub *sub = it->down[i];
1271                 strbuf_addf(path, "%s%s", baselen ? "/" : "", sub->name);
1272                 add_cache_tree(sub->cache_tree, revs, path);
1273                 strbuf_setlen(path, baselen);
1274         }
1275
1276 }
1277
1278 void add_index_objects_to_pending(struct rev_info *revs, unsigned flags)
1279 {
1280         int i;
1281
1282         read_cache();
1283         for (i = 0; i < active_nr; i++) {
1284                 struct cache_entry *ce = active_cache[i];
1285                 struct blob *blob;
1286
1287                 if (S_ISGITLINK(ce->ce_mode))
1288                         continue;
1289
1290                 blob = lookup_blob(ce->sha1);
1291                 if (!blob)
1292                         die("unable to add index blob to traversal");
1293                 add_pending_object_with_path(revs, &blob->object, "",
1294                                              ce->ce_mode, ce->name);
1295         }
1296
1297         if (active_cache_tree) {
1298                 struct strbuf path = STRBUF_INIT;
1299                 add_cache_tree(active_cache_tree, revs, &path);
1300                 strbuf_release(&path);
1301         }
1302 }
1303
1304 static int add_parents_only(struct rev_info *revs, const char *arg_, int flags)
1305 {
1306         unsigned char sha1[20];
1307         struct object *it;
1308         struct commit *commit;
1309         struct commit_list *parents;
1310         const char *arg = arg_;
1311
1312         if (*arg == '^') {
1313                 flags ^= UNINTERESTING | BOTTOM;
1314                 arg++;
1315         }
1316         if (get_sha1_committish(arg, sha1))
1317                 return 0;
1318         while (1) {
1319                 it = get_reference(revs, arg, sha1, 0);
1320                 if (!it && revs->ignore_missing)
1321                         return 0;
1322                 if (it->type != OBJ_TAG)
1323                         break;
1324                 if (!((struct tag*)it)->tagged)
1325                         return 0;
1326                 hashcpy(sha1, ((struct tag*)it)->tagged->oid.hash);
1327         }
1328         if (it->type != OBJ_COMMIT)
1329                 return 0;
1330         commit = (struct commit *)it;
1331         for (parents = commit->parents; parents; parents = parents->next) {
1332                 it = &parents->item->object;
1333                 it->flags |= flags;
1334                 add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
1335                 add_pending_object(revs, it, arg);
1336         }
1337         return 1;
1338 }
1339
1340 void init_revisions(struct rev_info *revs, const char *prefix)
1341 {
1342         memset(revs, 0, sizeof(*revs));
1343
1344         revs->abbrev = DEFAULT_ABBREV;
1345         revs->ignore_merges = 1;
1346         revs->simplify_history = 1;
1347         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
1348         DIFF_OPT_SET(&revs->pruning, QUICK);
1349         revs->pruning.add_remove = file_add_remove;
1350         revs->pruning.change = file_change;
1351         revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1352         revs->dense = 1;
1353         revs->prefix = prefix;
1354         revs->max_age = -1;
1355         revs->min_age = -1;
1356         revs->skip_count = -1;
1357         revs->max_count = -1;
1358         revs->max_parents = -1;
1359
1360         revs->commit_format = CMIT_FMT_DEFAULT;
1361
1362         init_grep_defaults();
1363         grep_init(&revs->grep_filter, prefix);
1364         revs->grep_filter.status_only = 1;
1365         revs->grep_filter.regflags = REG_NEWLINE;
1366
1367         diff_setup(&revs->diffopt);
1368         if (prefix && !revs->diffopt.prefix) {
1369                 revs->diffopt.prefix = prefix;
1370                 revs->diffopt.prefix_length = strlen(prefix);
1371         }
1372
1373         revs->notes_opt.use_default_notes = -1;
1374 }
1375
1376 static void add_pending_commit_list(struct rev_info *revs,
1377                                     struct commit_list *commit_list,
1378                                     unsigned int flags)
1379 {
1380         while (commit_list) {
1381                 struct object *object = &commit_list->item->object;
1382                 object->flags |= flags;
1383                 add_pending_object(revs, object, oid_to_hex(&object->oid));
1384                 commit_list = commit_list->next;
1385         }
1386 }
1387
1388 static void prepare_show_merge(struct rev_info *revs)
1389 {
1390         struct commit_list *bases;
1391         struct commit *head, *other;
1392         unsigned char sha1[20];
1393         const char **prune = NULL;
1394         int i, prune_num = 1; /* counting terminating NULL */
1395
1396         if (get_sha1("HEAD", sha1))
1397                 die("--merge without HEAD?");
1398         head = lookup_commit_or_die(sha1, "HEAD");
1399         if (get_sha1("MERGE_HEAD", sha1))
1400                 die("--merge without MERGE_HEAD?");
1401         other = lookup_commit_or_die(sha1, "MERGE_HEAD");
1402         add_pending_object(revs, &head->object, "HEAD");
1403         add_pending_object(revs, &other->object, "MERGE_HEAD");
1404         bases = get_merge_bases(head, other);
1405         add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
1406         add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
1407         free_commit_list(bases);
1408         head->object.flags |= SYMMETRIC_LEFT;
1409
1410         if (!active_nr)
1411                 read_cache();
1412         for (i = 0; i < active_nr; i++) {
1413                 const struct cache_entry *ce = active_cache[i];
1414                 if (!ce_stage(ce))
1415                         continue;
1416                 if (ce_path_match(ce, &revs->prune_data, NULL)) {
1417                         prune_num++;
1418                         REALLOC_ARRAY(prune, prune_num);
1419                         prune[prune_num-2] = ce->name;
1420                         prune[prune_num-1] = NULL;
1421                 }
1422                 while ((i+1 < active_nr) &&
1423                        ce_same_name(ce, active_cache[i+1]))
1424                         i++;
1425         }
1426         free_pathspec(&revs->prune_data);
1427         parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
1428                        PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
1429         revs->limited = 1;
1430 }
1431
1432 int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
1433 {
1434         struct object_context oc;
1435         char *dotdot;
1436         struct object *object;
1437         unsigned char sha1[20];
1438         int local_flags;
1439         const char *arg = arg_;
1440         int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
1441         unsigned get_sha1_flags = 0;
1442
1443         flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
1444
1445         dotdot = strstr(arg, "..");
1446         if (dotdot) {
1447                 unsigned char from_sha1[20];
1448                 const char *next = dotdot + 2;
1449                 const char *this = arg;
1450                 int symmetric = *next == '.';
1451                 unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
1452                 static const char head_by_default[] = "HEAD";
1453                 unsigned int a_flags;
1454
1455                 *dotdot = 0;
1456                 next += symmetric;
1457
1458                 if (!*next)
1459                         next = head_by_default;
1460                 if (dotdot == arg)
1461                         this = head_by_default;
1462                 if (this == head_by_default && next == head_by_default &&
1463                     !symmetric) {
1464                         /*
1465                          * Just ".."?  That is not a range but the
1466                          * pathspec for the parent directory.
1467                          */
1468                         if (!cant_be_filename) {
1469                                 *dotdot = '.';
1470                                 return -1;
1471                         }
1472                 }
1473                 if (!get_sha1_committish(this, from_sha1) &&
1474                     !get_sha1_committish(next, sha1)) {
1475                         struct object *a_obj, *b_obj;
1476
1477                         if (!cant_be_filename) {
1478                                 *dotdot = '.';
1479                                 verify_non_filename(revs->prefix, arg);
1480                         }
1481
1482                         a_obj = parse_object(from_sha1);
1483                         b_obj = parse_object(sha1);
1484                         if (!a_obj || !b_obj) {
1485                         missing:
1486                                 if (revs->ignore_missing)
1487                                         return 0;
1488                                 die(symmetric
1489                                     ? "Invalid symmetric difference expression %s"
1490                                     : "Invalid revision range %s", arg);
1491                         }
1492
1493                         if (!symmetric) {
1494                                 /* just A..B */
1495                                 a_flags = flags_exclude;
1496                         } else {
1497                                 /* A...B -- find merge bases between the two */
1498                                 struct commit *a, *b;
1499                                 struct commit_list *exclude;
1500
1501                                 a = (a_obj->type == OBJ_COMMIT
1502                                      ? (struct commit *)a_obj
1503                                      : lookup_commit_reference(a_obj->oid.hash));
1504                                 b = (b_obj->type == OBJ_COMMIT
1505                                      ? (struct commit *)b_obj
1506                                      : lookup_commit_reference(b_obj->oid.hash));
1507                                 if (!a || !b)
1508                                         goto missing;
1509                                 exclude = get_merge_bases(a, b);
1510                                 add_rev_cmdline_list(revs, exclude,
1511                                                      REV_CMD_MERGE_BASE,
1512                                                      flags_exclude);
1513                                 add_pending_commit_list(revs, exclude,
1514                                                         flags_exclude);
1515                                 free_commit_list(exclude);
1516
1517                                 a_flags = flags | SYMMETRIC_LEFT;
1518                         }
1519
1520                         a_obj->flags |= a_flags;
1521                         b_obj->flags |= flags;
1522                         add_rev_cmdline(revs, a_obj, this,
1523                                         REV_CMD_LEFT, a_flags);
1524                         add_rev_cmdline(revs, b_obj, next,
1525                                         REV_CMD_RIGHT, flags);
1526                         add_pending_object(revs, a_obj, this);
1527                         add_pending_object(revs, b_obj, next);
1528                         return 0;
1529                 }
1530                 *dotdot = '.';
1531         }
1532         dotdot = strstr(arg, "^@");
1533         if (dotdot && !dotdot[2]) {
1534                 *dotdot = 0;
1535                 if (add_parents_only(revs, arg, flags))
1536                         return 0;
1537                 *dotdot = '^';
1538         }
1539         dotdot = strstr(arg, "^!");
1540         if (dotdot && !dotdot[2]) {
1541                 *dotdot = 0;
1542                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM)))
1543                         *dotdot = '^';
1544         }
1545
1546         local_flags = 0;
1547         if (*arg == '^') {
1548                 local_flags = UNINTERESTING | BOTTOM;
1549                 arg++;
1550         }
1551
1552         if (revarg_opt & REVARG_COMMITTISH)
1553                 get_sha1_flags = GET_SHA1_COMMITTISH;
1554
1555         if (get_sha1_with_context(arg, get_sha1_flags, sha1, &oc))
1556                 return revs->ignore_missing ? 0 : -1;
1557         if (!cant_be_filename)
1558                 verify_non_filename(revs->prefix, arg);
1559         object = get_reference(revs, arg, sha1, flags ^ local_flags);
1560         add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
1561         add_pending_object_with_mode(revs, object, arg, oc.mode);
1562         return 0;
1563 }
1564
1565 struct cmdline_pathspec {
1566         int alloc;
1567         int nr;
1568         const char **path;
1569 };
1570
1571 static void append_prune_data(struct cmdline_pathspec *prune, const char **av)
1572 {
1573         while (*av) {
1574                 ALLOC_GROW(prune->path, prune->nr + 1, prune->alloc);
1575                 prune->path[prune->nr++] = *(av++);
1576         }
1577 }
1578
1579 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
1580                                      struct cmdline_pathspec *prune)
1581 {
1582         while (strbuf_getline(sb, stdin) != EOF) {
1583                 ALLOC_GROW(prune->path, prune->nr + 1, prune->alloc);
1584                 prune->path[prune->nr++] = xstrdup(sb->buf);
1585         }
1586 }
1587
1588 static void read_revisions_from_stdin(struct rev_info *revs,
1589                                       struct cmdline_pathspec *prune)
1590 {
1591         struct strbuf sb;
1592         int seen_dashdash = 0;
1593         int save_warning;
1594
1595         save_warning = warn_on_object_refname_ambiguity;
1596         warn_on_object_refname_ambiguity = 0;
1597
1598         strbuf_init(&sb, 1000);
1599         while (strbuf_getline(&sb, stdin) != EOF) {
1600                 int len = sb.len;
1601                 if (!len)
1602                         break;
1603                 if (sb.buf[0] == '-') {
1604                         if (len == 2 && sb.buf[1] == '-') {
1605                                 seen_dashdash = 1;
1606                                 break;
1607                         }
1608                         die("options not supported in --stdin mode");
1609                 }
1610                 if (handle_revision_arg(sb.buf, revs, 0,
1611                                         REVARG_CANNOT_BE_FILENAME))
1612                         die("bad revision '%s'", sb.buf);
1613         }
1614         if (seen_dashdash)
1615                 read_pathspec_from_stdin(revs, &sb, prune);
1616
1617         strbuf_release(&sb);
1618         warn_on_object_refname_ambiguity = save_warning;
1619 }
1620
1621 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1622 {
1623         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1624 }
1625
1626 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1627 {
1628         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1629 }
1630
1631 static void add_message_grep(struct rev_info *revs, const char *pattern)
1632 {
1633         add_grep(revs, pattern, GREP_PATTERN_BODY);
1634 }
1635
1636 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1637                                int *unkc, const char **unkv)
1638 {
1639         const char *arg = argv[0];
1640         const char *optarg;
1641         int argcount;
1642
1643         /* pseudo revision arguments */
1644         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1645             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1646             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1647             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1648             !strcmp(arg, "--bisect") || starts_with(arg, "--glob=") ||
1649             !strcmp(arg, "--indexed-objects") ||
1650             starts_with(arg, "--exclude=") ||
1651             starts_with(arg, "--branches=") || starts_with(arg, "--tags=") ||
1652             starts_with(arg, "--remotes=") || starts_with(arg, "--no-walk="))
1653         {
1654                 unkv[(*unkc)++] = arg;
1655                 return 1;
1656         }
1657
1658         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1659                 revs->max_count = atoi(optarg);
1660                 revs->no_walk = 0;
1661                 return argcount;
1662         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1663                 revs->skip_count = atoi(optarg);
1664                 return argcount;
1665         } else if ((*arg == '-') && isdigit(arg[1])) {
1666                 /* accept -<digit>, like traditional "head" */
1667                 if (strtol_i(arg + 1, 10, &revs->max_count) < 0 ||
1668                     revs->max_count < 0)
1669                         die("'%s': not a non-negative integer", arg + 1);
1670                 revs->no_walk = 0;
1671         } else if (!strcmp(arg, "-n")) {
1672                 if (argc <= 1)
1673                         return error("-n requires an argument");
1674                 revs->max_count = atoi(argv[1]);
1675                 revs->no_walk = 0;
1676                 return 2;
1677         } else if (starts_with(arg, "-n")) {
1678                 revs->max_count = atoi(arg + 2);
1679                 revs->no_walk = 0;
1680         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1681                 revs->max_age = atoi(optarg);
1682                 return argcount;
1683         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1684                 revs->max_age = approxidate(optarg);
1685                 return argcount;
1686         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1687                 revs->max_age = approxidate(optarg);
1688                 return argcount;
1689         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1690                 revs->min_age = atoi(optarg);
1691                 return argcount;
1692         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1693                 revs->min_age = approxidate(optarg);
1694                 return argcount;
1695         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1696                 revs->min_age = approxidate(optarg);
1697                 return argcount;
1698         } else if (!strcmp(arg, "--first-parent")) {
1699                 revs->first_parent_only = 1;
1700         } else if (!strcmp(arg, "--ancestry-path")) {
1701                 revs->ancestry_path = 1;
1702                 revs->simplify_history = 0;
1703                 revs->limited = 1;
1704         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1705                 init_reflog_walk(&revs->reflog_info);
1706         } else if (!strcmp(arg, "--default")) {
1707                 if (argc <= 1)
1708                         return error("bad --default argument");
1709                 revs->def = argv[1];
1710                 return 2;
1711         } else if (!strcmp(arg, "--merge")) {
1712                 revs->show_merge = 1;
1713         } else if (!strcmp(arg, "--topo-order")) {
1714                 revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1715                 revs->topo_order = 1;
1716         } else if (!strcmp(arg, "--simplify-merges")) {
1717                 revs->simplify_merges = 1;
1718                 revs->topo_order = 1;
1719                 revs->rewrite_parents = 1;
1720                 revs->simplify_history = 0;
1721                 revs->limited = 1;
1722         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1723                 revs->simplify_merges = 1;
1724                 revs->topo_order = 1;
1725                 revs->rewrite_parents = 1;
1726                 revs->simplify_history = 0;
1727                 revs->simplify_by_decoration = 1;
1728                 revs->limited = 1;
1729                 revs->prune = 1;
1730                 load_ref_decorations(DECORATE_SHORT_REFS);
1731         } else if (!strcmp(arg, "--date-order")) {
1732                 revs->sort_order = REV_SORT_BY_COMMIT_DATE;
1733                 revs->topo_order = 1;
1734         } else if (!strcmp(arg, "--author-date-order")) {
1735                 revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
1736                 revs->topo_order = 1;
1737         } else if (starts_with(arg, "--early-output")) {
1738                 int count = 100;
1739                 switch (arg[14]) {
1740                 case '=':
1741                         count = atoi(arg+15);
1742                         /* Fallthrough */
1743                 case 0:
1744                         revs->topo_order = 1;
1745                        revs->early_output = count;
1746                 }
1747         } else if (!strcmp(arg, "--parents")) {
1748                 revs->rewrite_parents = 1;
1749                 revs->print_parents = 1;
1750         } else if (!strcmp(arg, "--dense")) {
1751                 revs->dense = 1;
1752         } else if (!strcmp(arg, "--sparse")) {
1753                 revs->dense = 0;
1754         } else if (!strcmp(arg, "--show-all")) {
1755                 revs->show_all = 1;
1756         } else if (!strcmp(arg, "--remove-empty")) {
1757                 revs->remove_empty_trees = 1;
1758         } else if (!strcmp(arg, "--merges")) {
1759                 revs->min_parents = 2;
1760         } else if (!strcmp(arg, "--no-merges")) {
1761                 revs->max_parents = 1;
1762         } else if (starts_with(arg, "--min-parents=")) {
1763                 revs->min_parents = atoi(arg+14);
1764         } else if (starts_with(arg, "--no-min-parents")) {
1765                 revs->min_parents = 0;
1766         } else if (starts_with(arg, "--max-parents=")) {
1767                 revs->max_parents = atoi(arg+14);
1768         } else if (starts_with(arg, "--no-max-parents")) {
1769                 revs->max_parents = -1;
1770         } else if (!strcmp(arg, "--boundary")) {
1771                 revs->boundary = 1;
1772         } else if (!strcmp(arg, "--left-right")) {
1773                 revs->left_right = 1;
1774         } else if (!strcmp(arg, "--left-only")) {
1775                 if (revs->right_only)
1776                         die("--left-only is incompatible with --right-only"
1777                             " or --cherry");
1778                 revs->left_only = 1;
1779         } else if (!strcmp(arg, "--right-only")) {
1780                 if (revs->left_only)
1781                         die("--right-only is incompatible with --left-only");
1782                 revs->right_only = 1;
1783         } else if (!strcmp(arg, "--cherry")) {
1784                 if (revs->left_only)
1785                         die("--cherry is incompatible with --left-only");
1786                 revs->cherry_mark = 1;
1787                 revs->right_only = 1;
1788                 revs->max_parents = 1;
1789                 revs->limited = 1;
1790         } else if (!strcmp(arg, "--count")) {
1791                 revs->count = 1;
1792         } else if (!strcmp(arg, "--cherry-mark")) {
1793                 if (revs->cherry_pick)
1794                         die("--cherry-mark is incompatible with --cherry-pick");
1795                 revs->cherry_mark = 1;
1796                 revs->limited = 1; /* needs limit_list() */
1797         } else if (!strcmp(arg, "--cherry-pick")) {
1798                 if (revs->cherry_mark)
1799                         die("--cherry-pick is incompatible with --cherry-mark");
1800                 revs->cherry_pick = 1;
1801                 revs->limited = 1;
1802         } else if (!strcmp(arg, "--objects")) {
1803                 revs->tag_objects = 1;
1804                 revs->tree_objects = 1;
1805                 revs->blob_objects = 1;
1806         } else if (!strcmp(arg, "--objects-edge")) {
1807                 revs->tag_objects = 1;
1808                 revs->tree_objects = 1;
1809                 revs->blob_objects = 1;
1810                 revs->edge_hint = 1;
1811         } else if (!strcmp(arg, "--objects-edge-aggressive")) {
1812                 revs->tag_objects = 1;
1813                 revs->tree_objects = 1;
1814                 revs->blob_objects = 1;
1815                 revs->edge_hint = 1;
1816                 revs->edge_hint_aggressive = 1;
1817         } else if (!strcmp(arg, "--verify-objects")) {
1818                 revs->tag_objects = 1;
1819                 revs->tree_objects = 1;
1820                 revs->blob_objects = 1;
1821                 revs->verify_objects = 1;
1822         } else if (!strcmp(arg, "--unpacked")) {
1823                 revs->unpacked = 1;
1824         } else if (starts_with(arg, "--unpacked=")) {
1825                 die("--unpacked=<packfile> no longer supported.");
1826         } else if (!strcmp(arg, "-r")) {
1827                 revs->diff = 1;
1828                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1829         } else if (!strcmp(arg, "-t")) {
1830                 revs->diff = 1;
1831                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1832                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1833         } else if (!strcmp(arg, "-m")) {
1834                 revs->ignore_merges = 0;
1835         } else if (!strcmp(arg, "-c")) {
1836                 revs->diff = 1;
1837                 revs->dense_combined_merges = 0;
1838                 revs->combine_merges = 1;
1839         } else if (!strcmp(arg, "--cc")) {
1840                 revs->diff = 1;
1841                 revs->dense_combined_merges = 1;
1842                 revs->combine_merges = 1;
1843         } else if (!strcmp(arg, "-v")) {
1844                 revs->verbose_header = 1;
1845         } else if (!strcmp(arg, "--pretty")) {
1846                 revs->verbose_header = 1;
1847                 revs->pretty_given = 1;
1848                 get_commit_format(NULL, revs);
1849         } else if (starts_with(arg, "--pretty=") || starts_with(arg, "--format=")) {
1850                 /*
1851                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1852                  * not allowed, since the argument is optional.
1853                  */
1854                 revs->verbose_header = 1;
1855                 revs->pretty_given = 1;
1856                 get_commit_format(arg+9, revs);
1857         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
1858                 revs->show_notes = 1;
1859                 revs->show_notes_given = 1;
1860                 revs->notes_opt.use_default_notes = 1;
1861         } else if (!strcmp(arg, "--show-signature")) {
1862                 revs->show_signature = 1;
1863         } else if (!strcmp(arg, "--show-linear-break") ||
1864                    starts_with(arg, "--show-linear-break=")) {
1865                 if (starts_with(arg, "--show-linear-break="))
1866                         revs->break_bar = xstrdup(arg + 20);
1867                 else
1868                         revs->break_bar = "                    ..........";
1869                 revs->track_linear = 1;
1870                 revs->track_first_time = 1;
1871         } else if (starts_with(arg, "--show-notes=") ||
1872                    starts_with(arg, "--notes=")) {
1873                 struct strbuf buf = STRBUF_INIT;
1874                 revs->show_notes = 1;
1875                 revs->show_notes_given = 1;
1876                 if (starts_with(arg, "--show-notes")) {
1877                         if (revs->notes_opt.use_default_notes < 0)
1878                                 revs->notes_opt.use_default_notes = 1;
1879                         strbuf_addstr(&buf, arg+13);
1880                 }
1881                 else
1882                         strbuf_addstr(&buf, arg+8);
1883                 expand_notes_ref(&buf);
1884                 string_list_append(&revs->notes_opt.extra_notes_refs,
1885                                    strbuf_detach(&buf, NULL));
1886         } else if (!strcmp(arg, "--no-notes")) {
1887                 revs->show_notes = 0;
1888                 revs->show_notes_given = 1;
1889                 revs->notes_opt.use_default_notes = -1;
1890                 /* we have been strdup'ing ourselves, so trick
1891                  * string_list into free()ing strings */
1892                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
1893                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
1894                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
1895         } else if (!strcmp(arg, "--standard-notes")) {
1896                 revs->show_notes_given = 1;
1897                 revs->notes_opt.use_default_notes = 1;
1898         } else if (!strcmp(arg, "--no-standard-notes")) {
1899                 revs->notes_opt.use_default_notes = 0;
1900         } else if (!strcmp(arg, "--oneline")) {
1901                 revs->verbose_header = 1;
1902                 get_commit_format("oneline", revs);
1903                 revs->pretty_given = 1;
1904                 revs->abbrev_commit = 1;
1905         } else if (!strcmp(arg, "--graph")) {
1906                 revs->topo_order = 1;
1907                 revs->rewrite_parents = 1;
1908                 revs->graph = graph_init(revs);
1909         } else if (!strcmp(arg, "--root")) {
1910                 revs->show_root_diff = 1;
1911         } else if (!strcmp(arg, "--no-commit-id")) {
1912                 revs->no_commit_id = 1;
1913         } else if (!strcmp(arg, "--always")) {
1914                 revs->always_show_header = 1;
1915         } else if (!strcmp(arg, "--no-abbrev")) {
1916                 revs->abbrev = 0;
1917         } else if (!strcmp(arg, "--abbrev")) {
1918                 revs->abbrev = DEFAULT_ABBREV;
1919         } else if (starts_with(arg, "--abbrev=")) {
1920                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1921                 if (revs->abbrev < MINIMUM_ABBREV)
1922                         revs->abbrev = MINIMUM_ABBREV;
1923                 else if (revs->abbrev > 40)
1924                         revs->abbrev = 40;
1925         } else if (!strcmp(arg, "--abbrev-commit")) {
1926                 revs->abbrev_commit = 1;
1927                 revs->abbrev_commit_given = 1;
1928         } else if (!strcmp(arg, "--no-abbrev-commit")) {
1929                 revs->abbrev_commit = 0;
1930         } else if (!strcmp(arg, "--full-diff")) {
1931                 revs->diff = 1;
1932                 revs->full_diff = 1;
1933         } else if (!strcmp(arg, "--full-history")) {
1934                 revs->simplify_history = 0;
1935         } else if (!strcmp(arg, "--relative-date")) {
1936                 revs->date_mode.type = DATE_RELATIVE;
1937                 revs->date_mode_explicit = 1;
1938         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
1939                 parse_date_format(optarg, &revs->date_mode);
1940                 revs->date_mode_explicit = 1;
1941                 return argcount;
1942         } else if (!strcmp(arg, "--log-size")) {
1943                 revs->show_log_size = 1;
1944         }
1945         /*
1946          * Grepping the commit log
1947          */
1948         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
1949                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
1950                 return argcount;
1951         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
1952                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
1953                 return argcount;
1954         } else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
1955                 add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
1956                 return argcount;
1957         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
1958                 add_message_grep(revs, optarg);
1959                 return argcount;
1960         } else if (!strcmp(arg, "--grep-debug")) {
1961                 revs->grep_filter.debug = 1;
1962         } else if (!strcmp(arg, "--basic-regexp")) {
1963                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_BRE, &revs->grep_filter);
1964         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1965                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, &revs->grep_filter);
1966         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1967                 revs->grep_filter.regflags |= REG_ICASE;
1968                 DIFF_OPT_SET(&revs->diffopt, PICKAXE_IGNORE_CASE);
1969         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1970                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_FIXED, &revs->grep_filter);
1971         } else if (!strcmp(arg, "--perl-regexp")) {
1972                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_PCRE, &revs->grep_filter);
1973         } else if (!strcmp(arg, "--all-match")) {
1974                 revs->grep_filter.all_match = 1;
1975         } else if (!strcmp(arg, "--invert-grep")) {
1976                 revs->invert_grep = 1;
1977         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
1978                 if (strcmp(optarg, "none"))
1979                         git_log_output_encoding = xstrdup(optarg);
1980                 else
1981                         git_log_output_encoding = "";
1982                 return argcount;
1983         } else if (!strcmp(arg, "--reverse")) {
1984                 revs->reverse ^= 1;
1985         } else if (!strcmp(arg, "--children")) {
1986                 revs->children.name = "children";
1987                 revs->limited = 1;
1988         } else if (!strcmp(arg, "--ignore-missing")) {
1989                 revs->ignore_missing = 1;
1990         } else {
1991                 int opts = diff_opt_parse(&revs->diffopt, argv, argc, revs->prefix);
1992                 if (!opts)
1993                         unkv[(*unkc)++] = arg;
1994                 return opts;
1995         }
1996         if (revs->graph && revs->track_linear)
1997                 die("--show-linear-break and --graph are incompatible");
1998
1999         return 1;
2000 }
2001
2002 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
2003                         const struct option *options,
2004                         const char * const usagestr[])
2005 {
2006         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
2007                                     &ctx->cpidx, ctx->out);
2008         if (n <= 0) {
2009                 error("unknown option `%s'", ctx->argv[0]);
2010                 usage_with_options(usagestr, options);
2011         }
2012         ctx->argv += n;
2013         ctx->argc -= n;
2014 }
2015
2016 static int for_each_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data, const char *term) {
2017         struct strbuf bisect_refs = STRBUF_INIT;
2018         int status;
2019         strbuf_addf(&bisect_refs, "refs/bisect/%s", term);
2020         status = for_each_ref_in_submodule(submodule, bisect_refs.buf, fn, cb_data);
2021         strbuf_release(&bisect_refs);
2022         return status;
2023 }
2024
2025 static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
2026 {
2027         return for_each_bisect_ref(submodule, fn, cb_data, term_bad);
2028 }
2029
2030 static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
2031 {
2032         return for_each_bisect_ref(submodule, fn, cb_data, term_good);
2033 }
2034
2035 static int handle_revision_pseudo_opt(const char *submodule,
2036                                 struct rev_info *revs,
2037                                 int argc, const char **argv, int *flags)
2038 {
2039         const char *arg = argv[0];
2040         const char *optarg;
2041         int argcount;
2042
2043         /*
2044          * NOTE!
2045          *
2046          * Commands like "git shortlog" will not accept the options below
2047          * unless parse_revision_opt queues them (as opposed to erroring
2048          * out).
2049          *
2050          * When implementing your new pseudo-option, remember to
2051          * register it in the list at the top of handle_revision_opt.
2052          */
2053         if (!strcmp(arg, "--all")) {
2054                 handle_refs(submodule, revs, *flags, for_each_ref_submodule);
2055                 handle_refs(submodule, revs, *flags, head_ref_submodule);
2056                 clear_ref_exclusion(&revs->ref_excludes);
2057         } else if (!strcmp(arg, "--branches")) {
2058                 handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule);
2059                 clear_ref_exclusion(&revs->ref_excludes);
2060         } else if (!strcmp(arg, "--bisect")) {
2061                 read_bisect_terms(&term_bad, &term_good);
2062                 handle_refs(submodule, revs, *flags, for_each_bad_bisect_ref);
2063                 handle_refs(submodule, revs, *flags ^ (UNINTERESTING | BOTTOM), for_each_good_bisect_ref);
2064                 revs->bisect = 1;
2065         } else if (!strcmp(arg, "--tags")) {
2066                 handle_refs(submodule, revs, *flags, for_each_tag_ref_submodule);
2067                 clear_ref_exclusion(&revs->ref_excludes);
2068         } else if (!strcmp(arg, "--remotes")) {
2069                 handle_refs(submodule, revs, *flags, for_each_remote_ref_submodule);
2070                 clear_ref_exclusion(&revs->ref_excludes);
2071         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
2072                 struct all_refs_cb cb;
2073                 init_all_refs_cb(&cb, revs, *flags);
2074                 for_each_glob_ref(handle_one_ref, optarg, &cb);
2075                 clear_ref_exclusion(&revs->ref_excludes);
2076                 return argcount;
2077         } else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
2078                 add_ref_exclusion(&revs->ref_excludes, optarg);
2079                 return argcount;
2080         } else if (starts_with(arg, "--branches=")) {
2081                 struct all_refs_cb cb;
2082                 init_all_refs_cb(&cb, revs, *flags);
2083                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
2084                 clear_ref_exclusion(&revs->ref_excludes);
2085         } else if (starts_with(arg, "--tags=")) {
2086                 struct all_refs_cb cb;
2087                 init_all_refs_cb(&cb, revs, *flags);
2088                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
2089                 clear_ref_exclusion(&revs->ref_excludes);
2090         } else if (starts_with(arg, "--remotes=")) {
2091                 struct all_refs_cb cb;
2092                 init_all_refs_cb(&cb, revs, *flags);
2093                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
2094                 clear_ref_exclusion(&revs->ref_excludes);
2095         } else if (!strcmp(arg, "--reflog")) {
2096                 add_reflogs_to_pending(revs, *flags);
2097         } else if (!strcmp(arg, "--indexed-objects")) {
2098                 add_index_objects_to_pending(revs, *flags);
2099         } else if (!strcmp(arg, "--not")) {
2100                 *flags ^= UNINTERESTING | BOTTOM;
2101         } else if (!strcmp(arg, "--no-walk")) {
2102                 revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2103         } else if (starts_with(arg, "--no-walk=")) {
2104                 /*
2105                  * Detached form ("--no-walk X" as opposed to "--no-walk=X")
2106                  * not allowed, since the argument is optional.
2107                  */
2108                 if (!strcmp(arg + 10, "sorted"))
2109                         revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2110                 else if (!strcmp(arg + 10, "unsorted"))
2111                         revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
2112                 else
2113                         return error("invalid argument to --no-walk");
2114         } else if (!strcmp(arg, "--do-walk")) {
2115                 revs->no_walk = 0;
2116         } else {
2117                 return 0;
2118         }
2119
2120         return 1;
2121 }
2122
2123 static void NORETURN diagnose_missing_default(const char *def)
2124 {
2125         unsigned char sha1[20];
2126         int flags;
2127         const char *refname;
2128
2129         refname = resolve_ref_unsafe(def, 0, sha1, &flags);
2130         if (!refname || !(flags & REF_ISSYMREF) || (flags & REF_ISBROKEN))
2131                 die(_("your current branch appears to be broken"));
2132
2133         skip_prefix(refname, "refs/heads/", &refname);
2134         die(_("your current branch '%s' does not have any commits yet"),
2135             refname);
2136 }
2137
2138 /*
2139  * Parse revision information, filling in the "rev_info" structure,
2140  * and removing the used arguments from the argument list.
2141  *
2142  * Returns the number of arguments left that weren't recognized
2143  * (which are also moved to the head of the argument list)
2144  */
2145 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
2146 {
2147         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0, revarg_opt;
2148         struct cmdline_pathspec prune_data;
2149         const char *submodule = NULL;
2150
2151         memset(&prune_data, 0, sizeof(prune_data));
2152         if (opt)
2153                 submodule = opt->submodule;
2154
2155         /* First, search for "--" */
2156         if (opt && opt->assume_dashdash) {
2157                 seen_dashdash = 1;
2158         } else {
2159                 seen_dashdash = 0;
2160                 for (i = 1; i < argc; i++) {
2161                         const char *arg = argv[i];
2162                         if (strcmp(arg, "--"))
2163                                 continue;
2164                         argv[i] = NULL;
2165                         argc = i;
2166                         if (argv[i + 1])
2167                                 append_prune_data(&prune_data, argv + i + 1);
2168                         seen_dashdash = 1;
2169                         break;
2170                 }
2171         }
2172
2173         /* Second, deal with arguments and options */
2174         flags = 0;
2175         revarg_opt = opt ? opt->revarg_opt : 0;
2176         if (seen_dashdash)
2177                 revarg_opt |= REVARG_CANNOT_BE_FILENAME;
2178         read_from_stdin = 0;
2179         for (left = i = 1; i < argc; i++) {
2180                 const char *arg = argv[i];
2181                 if (*arg == '-') {
2182                         int opts;
2183
2184                         opts = handle_revision_pseudo_opt(submodule,
2185                                                 revs, argc - i, argv + i,
2186                                                 &flags);
2187                         if (opts > 0) {
2188                                 i += opts - 1;
2189                                 continue;
2190                         }
2191
2192                         if (!strcmp(arg, "--stdin")) {
2193                                 if (revs->disable_stdin) {
2194                                         argv[left++] = arg;
2195                                         continue;
2196                                 }
2197                                 if (read_from_stdin++)
2198                                         die("--stdin given twice?");
2199                                 read_revisions_from_stdin(revs, &prune_data);
2200                                 continue;
2201                         }
2202
2203                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
2204                         if (opts > 0) {
2205                                 i += opts - 1;
2206                                 continue;
2207                         }
2208                         if (opts < 0)
2209                                 exit(128);
2210                         continue;
2211                 }
2212
2213
2214                 if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
2215                         int j;
2216                         if (seen_dashdash || *arg == '^')
2217                                 die("bad revision '%s'", arg);
2218
2219                         /* If we didn't have a "--":
2220                          * (1) all filenames must exist;
2221                          * (2) all rev-args must not be interpretable
2222                          *     as a valid filename.
2223                          * but the latter we have checked in the main loop.
2224                          */
2225                         for (j = i; j < argc; j++)
2226                                 verify_filename(revs->prefix, argv[j], j == i);
2227
2228                         append_prune_data(&prune_data, argv + i);
2229                         break;
2230                 }
2231                 else
2232                         got_rev_arg = 1;
2233         }
2234
2235         if (prune_data.nr) {
2236                 /*
2237                  * If we need to introduce the magic "a lone ':' means no
2238                  * pathspec whatsoever", here is the place to do so.
2239                  *
2240                  * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
2241                  *      prune_data.nr = 0;
2242                  *      prune_data.alloc = 0;
2243                  *      free(prune_data.path);
2244                  *      prune_data.path = NULL;
2245                  * } else {
2246                  *      terminate prune_data.alloc with NULL and
2247                  *      call init_pathspec() to set revs->prune_data here.
2248                  * }
2249                  */
2250                 ALLOC_GROW(prune_data.path, prune_data.nr + 1, prune_data.alloc);
2251                 prune_data.path[prune_data.nr++] = NULL;
2252                 parse_pathspec(&revs->prune_data, 0, 0,
2253                                revs->prefix, prune_data.path);
2254         }
2255
2256         if (revs->def == NULL)
2257                 revs->def = opt ? opt->def : NULL;
2258         if (opt && opt->tweak)
2259                 opt->tweak(revs, opt);
2260         if (revs->show_merge)
2261                 prepare_show_merge(revs);
2262         if (revs->def && !revs->pending.nr && !got_rev_arg) {
2263                 unsigned char sha1[20];
2264                 struct object *object;
2265                 struct object_context oc;
2266                 if (get_sha1_with_context(revs->def, 0, sha1, &oc))
2267                         diagnose_missing_default(revs->def);
2268                 object = get_reference(revs, revs->def, sha1, 0);
2269                 add_pending_object_with_mode(revs, object, revs->def, oc.mode);
2270         }
2271
2272         /* Did the user ask for any diff output? Run the diff! */
2273         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
2274                 revs->diff = 1;
2275
2276         /* Pickaxe, diff-filter and rename following need diffs */
2277         if (revs->diffopt.pickaxe ||
2278             revs->diffopt.filter ||
2279             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
2280                 revs->diff = 1;
2281
2282         if (revs->topo_order)
2283                 revs->limited = 1;
2284
2285         if (revs->prune_data.nr) {
2286                 copy_pathspec(&revs->pruning.pathspec, &revs->prune_data);
2287                 /* Can't prune commits with rename following: the paths change.. */
2288                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
2289                         revs->prune = 1;
2290                 if (!revs->full_diff)
2291                         copy_pathspec(&revs->diffopt.pathspec,
2292                                       &revs->prune_data);
2293         }
2294         if (revs->combine_merges)
2295                 revs->ignore_merges = 0;
2296         revs->diffopt.abbrev = revs->abbrev;
2297
2298         if (revs->line_level_traverse) {
2299                 revs->limited = 1;
2300                 revs->topo_order = 1;
2301         }
2302
2303         diff_setup_done(&revs->diffopt);
2304
2305         grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
2306                                  &revs->grep_filter);
2307         compile_grep_patterns(&revs->grep_filter);
2308
2309         if (revs->reverse && revs->reflog_info)
2310                 die("cannot combine --reverse with --walk-reflogs");
2311         if (revs->rewrite_parents && revs->children.name)
2312                 die("cannot combine --parents and --children");
2313
2314         /*
2315          * Limitations on the graph functionality
2316          */
2317         if (revs->reverse && revs->graph)
2318                 die("cannot combine --reverse with --graph");
2319
2320         if (revs->reflog_info && revs->graph)
2321                 die("cannot combine --walk-reflogs with --graph");
2322         if (revs->no_walk && revs->graph)
2323                 die("cannot combine --no-walk with --graph");
2324         if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
2325                 die("cannot use --grep-reflog without --walk-reflogs");
2326
2327         if (revs->first_parent_only && revs->bisect)
2328                 die(_("--first-parent is incompatible with --bisect"));
2329
2330         return left;
2331 }
2332
2333 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
2334 {
2335         struct commit_list *l = xcalloc(1, sizeof(*l));
2336
2337         l->item = child;
2338         l->next = add_decoration(&revs->children, &parent->object, l);
2339 }
2340
2341 static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
2342 {
2343         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2344         struct commit_list **pp, *p;
2345         int surviving_parents;
2346
2347         /* Examine existing parents while marking ones we have seen... */
2348         pp = &commit->parents;
2349         surviving_parents = 0;
2350         while ((p = *pp) != NULL) {
2351                 struct commit *parent = p->item;
2352                 if (parent->object.flags & TMP_MARK) {
2353                         *pp = p->next;
2354                         if (ts)
2355                                 compact_treesame(revs, commit, surviving_parents);
2356                         continue;
2357                 }
2358                 parent->object.flags |= TMP_MARK;
2359                 surviving_parents++;
2360                 pp = &p->next;
2361         }
2362         /* clear the temporary mark */
2363         for (p = commit->parents; p; p = p->next) {
2364                 p->item->object.flags &= ~TMP_MARK;
2365         }
2366         /* no update_treesame() - removing duplicates can't affect TREESAME */
2367         return surviving_parents;
2368 }
2369
2370 struct merge_simplify_state {
2371         struct commit *simplified;
2372 };
2373
2374 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
2375 {
2376         struct merge_simplify_state *st;
2377
2378         st = lookup_decoration(&revs->merge_simplification, &commit->object);
2379         if (!st) {
2380                 st = xcalloc(1, sizeof(*st));
2381                 add_decoration(&revs->merge_simplification, &commit->object, st);
2382         }
2383         return st;
2384 }
2385
2386 static int mark_redundant_parents(struct rev_info *revs, struct commit *commit)
2387 {
2388         struct commit_list *h = reduce_heads(commit->parents);
2389         int i = 0, marked = 0;
2390         struct commit_list *po, *pn;
2391
2392         /* Want these for sanity-checking only */
2393         int orig_cnt = commit_list_count(commit->parents);
2394         int cnt = commit_list_count(h);
2395
2396         /*
2397          * Not ready to remove items yet, just mark them for now, based
2398          * on the output of reduce_heads(). reduce_heads outputs the reduced
2399          * set in its original order, so this isn't too hard.
2400          */
2401         po = commit->parents;
2402         pn = h;
2403         while (po) {
2404                 if (pn && po->item == pn->item) {
2405                         pn = pn->next;
2406                         i++;
2407                 } else {
2408                         po->item->object.flags |= TMP_MARK;
2409                         marked++;
2410                 }
2411                 po=po->next;
2412         }
2413
2414         if (i != cnt || cnt+marked != orig_cnt)
2415                 die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
2416
2417         free_commit_list(h);
2418
2419         return marked;
2420 }
2421
2422 static int mark_treesame_root_parents(struct rev_info *revs, struct commit *commit)
2423 {
2424         struct commit_list *p;
2425         int marked = 0;
2426
2427         for (p = commit->parents; p; p = p->next) {
2428                 struct commit *parent = p->item;
2429                 if (!parent->parents && (parent->object.flags & TREESAME)) {
2430                         parent->object.flags |= TMP_MARK;
2431                         marked++;
2432                 }
2433         }
2434
2435         return marked;
2436 }
2437
2438 /*
2439  * Awkward naming - this means one parent we are TREESAME to.
2440  * cf mark_treesame_root_parents: root parents that are TREESAME (to an
2441  * empty tree). Better name suggestions?
2442  */
2443 static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
2444 {
2445         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2446         struct commit *unmarked = NULL, *marked = NULL;
2447         struct commit_list *p;
2448         unsigned n;
2449
2450         for (p = commit->parents, n = 0; p; p = p->next, n++) {
2451                 if (ts->treesame[n]) {
2452                         if (p->item->object.flags & TMP_MARK) {
2453                                 if (!marked)
2454                                         marked = p->item;
2455                         } else {
2456                                 if (!unmarked) {
2457                                         unmarked = p->item;
2458                                         break;
2459                                 }
2460                         }
2461                 }
2462         }
2463
2464         /*
2465          * If we are TREESAME to a marked-for-deletion parent, but not to any
2466          * unmarked parents, unmark the first TREESAME parent. This is the
2467          * parent that the default simplify_history==1 scan would have followed,
2468          * and it doesn't make sense to omit that path when asking for a
2469          * simplified full history. Retaining it improves the chances of
2470          * understanding odd missed merges that took an old version of a file.
2471          *
2472          * Example:
2473          *
2474          *   I--------*X       A modified the file, but mainline merge X used
2475          *    \       /        "-s ours", so took the version from I. X is
2476          *     `-*A--'         TREESAME to I and !TREESAME to A.
2477          *
2478          * Default log from X would produce "I". Without this check,
2479          * --full-history --simplify-merges would produce "I-A-X", showing
2480          * the merge commit X and that it changed A, but not making clear that
2481          * it had just taken the I version. With this check, the topology above
2482          * is retained.
2483          *
2484          * Note that it is possible that the simplification chooses a different
2485          * TREESAME parent from the default, in which case this test doesn't
2486          * activate, and we _do_ drop the default parent. Example:
2487          *
2488          *   I------X         A modified the file, but it was reverted in B,
2489          *    \    /          meaning mainline merge X is TREESAME to both
2490          *    *A-*B           parents.
2491          *
2492          * Default log would produce "I" by following the first parent;
2493          * --full-history --simplify-merges will produce "I-A-B". But this is a
2494          * reasonable result - it presents a logical full history leading from
2495          * I to X, and X is not an important merge.
2496          */
2497         if (!unmarked && marked) {
2498                 marked->object.flags &= ~TMP_MARK;
2499                 return 1;
2500         }
2501
2502         return 0;
2503 }
2504
2505 static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
2506 {
2507         struct commit_list **pp, *p;
2508         int nth_parent, removed = 0;
2509
2510         pp = &commit->parents;
2511         nth_parent = 0;
2512         while ((p = *pp) != NULL) {
2513                 struct commit *parent = p->item;
2514                 if (parent->object.flags & TMP_MARK) {
2515                         parent->object.flags &= ~TMP_MARK;
2516                         *pp = p->next;
2517                         free(p);
2518                         removed++;
2519                         compact_treesame(revs, commit, nth_parent);
2520                         continue;
2521                 }
2522                 pp = &p->next;
2523                 nth_parent++;
2524         }
2525
2526         /* Removing parents can only increase TREESAMEness */
2527         if (removed && !(commit->object.flags & TREESAME))
2528                 update_treesame(revs, commit);
2529
2530         return nth_parent;
2531 }
2532
2533 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
2534 {
2535         struct commit_list *p;
2536         struct commit *parent;
2537         struct merge_simplify_state *st, *pst;
2538         int cnt;
2539
2540         st = locate_simplify_state(revs, commit);
2541
2542         /*
2543          * Have we handled this one?
2544          */
2545         if (st->simplified)
2546                 return tail;
2547
2548         /*
2549          * An UNINTERESTING commit simplifies to itself, so does a
2550          * root commit.  We do not rewrite parents of such commit
2551          * anyway.
2552          */
2553         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
2554                 st->simplified = commit;
2555                 return tail;
2556         }
2557
2558         /*
2559          * Do we know what commit all of our parents that matter
2560          * should be rewritten to?  Otherwise we are not ready to
2561          * rewrite this one yet.
2562          */
2563         for (cnt = 0, p = commit->parents; p; p = p->next) {
2564                 pst = locate_simplify_state(revs, p->item);
2565                 if (!pst->simplified) {
2566                         tail = &commit_list_insert(p->item, tail)->next;
2567                         cnt++;
2568                 }
2569                 if (revs->first_parent_only)
2570                         break;
2571         }
2572         if (cnt) {
2573                 tail = &commit_list_insert(commit, tail)->next;
2574                 return tail;
2575         }
2576
2577         /*
2578          * Rewrite our list of parents. Note that this cannot
2579          * affect our TREESAME flags in any way - a commit is
2580          * always TREESAME to its simplification.
2581          */
2582         for (p = commit->parents; p; p = p->next) {
2583                 pst = locate_simplify_state(revs, p->item);
2584                 p->item = pst->simplified;
2585                 if (revs->first_parent_only)
2586                         break;
2587         }
2588
2589         if (revs->first_parent_only)
2590                 cnt = 1;
2591         else
2592                 cnt = remove_duplicate_parents(revs, commit);
2593
2594         /*
2595          * It is possible that we are a merge and one side branch
2596          * does not have any commit that touches the given paths;
2597          * in such a case, the immediate parent from that branch
2598          * will be rewritten to be the merge base.
2599          *
2600          *      o----X          X: the commit we are looking at;
2601          *     /    /           o: a commit that touches the paths;
2602          * ---o----'
2603          *
2604          * Further, a merge of an independent branch that doesn't
2605          * touch the path will reduce to a treesame root parent:
2606          *
2607          *  ----o----X          X: the commit we are looking at;
2608          *          /           o: a commit that touches the paths;
2609          *         r            r: a root commit not touching the paths
2610          *
2611          * Detect and simplify both cases.
2612          */
2613         if (1 < cnt) {
2614                 int marked = mark_redundant_parents(revs, commit);
2615                 marked += mark_treesame_root_parents(revs, commit);
2616                 if (marked)
2617                         marked -= leave_one_treesame_to_parent(revs, commit);
2618                 if (marked)
2619                         cnt = remove_marked_parents(revs, commit);
2620         }
2621
2622         /*
2623          * A commit simplifies to itself if it is a root, if it is
2624          * UNINTERESTING, if it touches the given paths, or if it is a
2625          * merge and its parents don't simplify to one relevant commit
2626          * (the first two cases are already handled at the beginning of
2627          * this function).
2628          *
2629          * Otherwise, it simplifies to what its sole relevant parent
2630          * simplifies to.
2631          */
2632         if (!cnt ||
2633             (commit->object.flags & UNINTERESTING) ||
2634             !(commit->object.flags & TREESAME) ||
2635             (parent = one_relevant_parent(revs, commit->parents)) == NULL)
2636                 st->simplified = commit;
2637         else {
2638                 pst = locate_simplify_state(revs, parent);
2639                 st->simplified = pst->simplified;
2640         }
2641         return tail;
2642 }
2643
2644 static void simplify_merges(struct rev_info *revs)
2645 {
2646         struct commit_list *list, *next;
2647         struct commit_list *yet_to_do, **tail;
2648         struct commit *commit;
2649
2650         if (!revs->prune)
2651                 return;
2652
2653         /* feed the list reversed */
2654         yet_to_do = NULL;
2655         for (list = revs->commits; list; list = next) {
2656                 commit = list->item;
2657                 next = list->next;
2658                 /*
2659                  * Do not free(list) here yet; the original list
2660                  * is used later in this function.
2661                  */
2662                 commit_list_insert(commit, &yet_to_do);
2663         }
2664         while (yet_to_do) {
2665                 list = yet_to_do;
2666                 yet_to_do = NULL;
2667                 tail = &yet_to_do;
2668                 while (list) {
2669                         commit = pop_commit(&list);
2670                         tail = simplify_one(revs, commit, tail);
2671                 }
2672         }
2673
2674         /* clean up the result, removing the simplified ones */
2675         list = revs->commits;
2676         revs->commits = NULL;
2677         tail = &revs->commits;
2678         while (list) {
2679                 struct merge_simplify_state *st;
2680
2681                 commit = pop_commit(&list);
2682                 st = locate_simplify_state(revs, commit);
2683                 if (st->simplified == commit)
2684                         tail = &commit_list_insert(commit, tail)->next;
2685         }
2686 }
2687
2688 static void set_children(struct rev_info *revs)
2689 {
2690         struct commit_list *l;
2691         for (l = revs->commits; l; l = l->next) {
2692                 struct commit *commit = l->item;
2693                 struct commit_list *p;
2694
2695                 for (p = commit->parents; p; p = p->next)
2696                         add_child(revs, p->item, commit);
2697         }
2698 }
2699
2700 void reset_revision_walk(void)
2701 {
2702         clear_object_flags(SEEN | ADDED | SHOWN);
2703 }
2704
2705 int prepare_revision_walk(struct rev_info *revs)
2706 {
2707         int i;
2708         struct object_array old_pending;
2709         struct commit_list **next = &revs->commits;
2710
2711         memcpy(&old_pending, &revs->pending, sizeof(old_pending));
2712         revs->pending.nr = 0;
2713         revs->pending.alloc = 0;
2714         revs->pending.objects = NULL;
2715         for (i = 0; i < old_pending.nr; i++) {
2716                 struct object_array_entry *e = old_pending.objects + i;
2717                 struct commit *commit = handle_commit(revs, e);
2718                 if (commit) {
2719                         if (!(commit->object.flags & SEEN)) {
2720                                 commit->object.flags |= SEEN;
2721                                 next = commit_list_append(commit, next);
2722                         }
2723                 }
2724         }
2725         if (!revs->leak_pending)
2726                 object_array_clear(&old_pending);
2727
2728         /* Signal whether we need per-parent treesame decoration */
2729         if (revs->simplify_merges ||
2730             (revs->limited && limiting_can_increase_treesame(revs)))
2731                 revs->treesame.name = "treesame";
2732
2733         if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
2734                 commit_list_sort_by_date(&revs->commits);
2735         if (revs->no_walk)
2736                 return 0;
2737         if (revs->limited)
2738                 if (limit_list(revs) < 0)
2739                         return -1;
2740         if (revs->topo_order)
2741                 sort_in_topological_order(&revs->commits, revs->sort_order);
2742         if (revs->line_level_traverse)
2743                 line_log_filter(revs);
2744         if (revs->simplify_merges)
2745                 simplify_merges(revs);
2746         if (revs->children.name)
2747                 set_children(revs);
2748         return 0;
2749 }
2750
2751 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
2752 {
2753         struct commit_list *cache = NULL;
2754
2755         for (;;) {
2756                 struct commit *p = *pp;
2757                 if (!revs->limited)
2758                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
2759                                 return rewrite_one_error;
2760                 if (p->object.flags & UNINTERESTING)
2761                         return rewrite_one_ok;
2762                 if (!(p->object.flags & TREESAME))
2763                         return rewrite_one_ok;
2764                 if (!p->parents)
2765                         return rewrite_one_noparents;
2766                 if ((p = one_relevant_parent(revs, p->parents)) == NULL)
2767                         return rewrite_one_ok;
2768                 *pp = p;
2769         }
2770 }
2771
2772 int rewrite_parents(struct rev_info *revs, struct commit *commit,
2773         rewrite_parent_fn_t rewrite_parent)
2774 {
2775         struct commit_list **pp = &commit->parents;
2776         while (*pp) {
2777                 struct commit_list *parent = *pp;
2778                 switch (rewrite_parent(revs, &parent->item)) {
2779                 case rewrite_one_ok:
2780                         break;
2781                 case rewrite_one_noparents:
2782                         *pp = parent->next;
2783                         continue;
2784                 case rewrite_one_error:
2785                         return -1;
2786                 }
2787                 pp = &parent->next;
2788         }
2789         remove_duplicate_parents(revs, commit);
2790         return 0;
2791 }
2792
2793 static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
2794 {
2795         char *person, *endp;
2796         size_t len, namelen, maillen;
2797         const char *name;
2798         const char *mail;
2799         struct ident_split ident;
2800
2801         person = strstr(buf->buf, what);
2802         if (!person)
2803                 return 0;
2804
2805         person += strlen(what);
2806         endp = strchr(person, '\n');
2807         if (!endp)
2808                 return 0;
2809
2810         len = endp - person;
2811
2812         if (split_ident_line(&ident, person, len))
2813                 return 0;
2814
2815         mail = ident.mail_begin;
2816         maillen = ident.mail_end - ident.mail_begin;
2817         name = ident.name_begin;
2818         namelen = ident.name_end - ident.name_begin;
2819
2820         if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
2821                 struct strbuf namemail = STRBUF_INIT;
2822
2823                 strbuf_addf(&namemail, "%.*s <%.*s>",
2824                             (int)namelen, name, (int)maillen, mail);
2825
2826                 strbuf_splice(buf, ident.name_begin - buf->buf,
2827                               ident.mail_end - ident.name_begin + 1,
2828                               namemail.buf, namemail.len);
2829
2830                 strbuf_release(&namemail);
2831
2832                 return 1;
2833         }
2834
2835         return 0;
2836 }
2837
2838 static int commit_match(struct commit *commit, struct rev_info *opt)
2839 {
2840         int retval;
2841         const char *encoding;
2842         const char *message;
2843         struct strbuf buf = STRBUF_INIT;
2844
2845         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
2846                 return 1;
2847
2848         /* Prepend "fake" headers as needed */
2849         if (opt->grep_filter.use_reflog_filter) {
2850                 strbuf_addstr(&buf, "reflog ");
2851                 get_reflog_message(&buf, opt->reflog_info);
2852                 strbuf_addch(&buf, '\n');
2853         }
2854
2855         /*
2856          * We grep in the user's output encoding, under the assumption that it
2857          * is the encoding they are most likely to write their grep pattern
2858          * for. In addition, it means we will match the "notes" encoding below,
2859          * so we will not end up with a buffer that has two different encodings
2860          * in it.
2861          */
2862         encoding = get_log_output_encoding();
2863         message = logmsg_reencode(commit, NULL, encoding);
2864
2865         /* Copy the commit to temporary if we are using "fake" headers */
2866         if (buf.len)
2867                 strbuf_addstr(&buf, message);
2868
2869         if (opt->grep_filter.header_list && opt->mailmap) {
2870                 if (!buf.len)
2871                         strbuf_addstr(&buf, message);
2872
2873                 commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
2874                 commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
2875         }
2876
2877         /* Append "fake" message parts as needed */
2878         if (opt->show_notes) {
2879                 if (!buf.len)
2880                         strbuf_addstr(&buf, message);
2881                 format_display_notes(commit->object.oid.hash, &buf, encoding, 1);
2882         }
2883
2884         /*
2885          * Find either in the original commit message, or in the temporary.
2886          * Note that we cast away the constness of "message" here. It is
2887          * const because it may come from the cached commit buffer. That's OK,
2888          * because we know that it is modifiable heap memory, and that while
2889          * grep_buffer may modify it for speed, it will restore any
2890          * changes before returning.
2891          */
2892         if (buf.len)
2893                 retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
2894         else
2895                 retval = grep_buffer(&opt->grep_filter,
2896                                      (char *)message, strlen(message));
2897         strbuf_release(&buf);
2898         unuse_commit_buffer(commit, message);
2899         return opt->invert_grep ? !retval : retval;
2900 }
2901
2902 static inline int want_ancestry(const struct rev_info *revs)
2903 {
2904         return (revs->rewrite_parents || revs->children.name);
2905 }
2906
2907 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
2908 {
2909         if (commit->object.flags & SHOWN)
2910                 return commit_ignore;
2911         if (revs->unpacked && has_sha1_pack(commit->object.oid.hash))
2912                 return commit_ignore;
2913         if (revs->show_all)
2914                 return commit_show;
2915         if (commit->object.flags & UNINTERESTING)
2916                 return commit_ignore;
2917         if (revs->min_age != -1 && (commit->date > revs->min_age))
2918                 return commit_ignore;
2919         if (revs->min_parents || (revs->max_parents >= 0)) {
2920                 int n = commit_list_count(commit->parents);
2921                 if ((n < revs->min_parents) ||
2922                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
2923                         return commit_ignore;
2924         }
2925         if (!commit_match(commit, revs))
2926                 return commit_ignore;
2927         if (revs->prune && revs->dense) {
2928                 /* Commit without changes? */
2929                 if (commit->object.flags & TREESAME) {
2930                         int n;
2931                         struct commit_list *p;
2932                         /* drop merges unless we want parenthood */
2933                         if (!want_ancestry(revs))
2934                                 return commit_ignore;
2935                         /*
2936                          * If we want ancestry, then need to keep any merges
2937                          * between relevant commits to tie together topology.
2938                          * For consistency with TREESAME and simplification
2939                          * use "relevant" here rather than just INTERESTING,
2940                          * to treat bottom commit(s) as part of the topology.
2941                          */
2942                         for (n = 0, p = commit->parents; p; p = p->next)
2943                                 if (relevant_commit(p->item))
2944                                         if (++n >= 2)
2945                                                 return commit_show;
2946                         return commit_ignore;
2947                 }
2948         }
2949         return commit_show;
2950 }
2951
2952 define_commit_slab(saved_parents, struct commit_list *);
2953
2954 #define EMPTY_PARENT_LIST ((struct commit_list *)-1)
2955
2956 /*
2957  * You may only call save_parents() once per commit (this is checked
2958  * for non-root commits).
2959  */
2960 static void save_parents(struct rev_info *revs, struct commit *commit)
2961 {
2962         struct commit_list **pp;
2963
2964         if (!revs->saved_parents_slab) {
2965                 revs->saved_parents_slab = xmalloc(sizeof(struct saved_parents));
2966                 init_saved_parents(revs->saved_parents_slab);
2967         }
2968
2969         pp = saved_parents_at(revs->saved_parents_slab, commit);
2970
2971         /*
2972          * When walking with reflogs, we may visit the same commit
2973          * several times: once for each appearance in the reflog.
2974          *
2975          * In this case, save_parents() will be called multiple times.
2976          * We want to keep only the first set of parents.  We need to
2977          * store a sentinel value for an empty (i.e., NULL) parent
2978          * list to distinguish it from a not-yet-saved list, however.
2979          */
2980         if (*pp)
2981                 return;
2982         if (commit->parents)
2983                 *pp = copy_commit_list(commit->parents);
2984         else
2985                 *pp = EMPTY_PARENT_LIST;
2986 }
2987
2988 static void free_saved_parents(struct rev_info *revs)
2989 {
2990         if (revs->saved_parents_slab)
2991                 clear_saved_parents(revs->saved_parents_slab);
2992 }
2993
2994 struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit)
2995 {
2996         struct commit_list *parents;
2997
2998         if (!revs->saved_parents_slab)
2999                 return commit->parents;
3000
3001         parents = *saved_parents_at(revs->saved_parents_slab, commit);
3002         if (parents == EMPTY_PARENT_LIST)
3003                 return NULL;
3004         return parents;
3005 }
3006
3007 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
3008 {
3009         enum commit_action action = get_commit_action(revs, commit);
3010
3011         if (action == commit_show &&
3012             !revs->show_all &&
3013             revs->prune && revs->dense && want_ancestry(revs)) {
3014                 /*
3015                  * --full-diff on simplified parents is no good: it
3016                  * will show spurious changes from the commits that
3017                  * were elided.  So we save the parents on the side
3018                  * when --full-diff is in effect.
3019                  */
3020                 if (revs->full_diff)
3021                         save_parents(revs, commit);
3022                 if (rewrite_parents(revs, commit, rewrite_one) < 0)
3023                         return commit_error;
3024         }
3025         return action;
3026 }
3027
3028 static void track_linear(struct rev_info *revs, struct commit *commit)
3029 {
3030         if (revs->track_first_time) {
3031                 revs->linear = 1;
3032                 revs->track_first_time = 0;
3033         } else {
3034                 struct commit_list *p;
3035                 for (p = revs->previous_parents; p; p = p->next)
3036                         if (p->item == NULL || /* first commit */
3037                             !oidcmp(&p->item->object.oid, &commit->object.oid))
3038                                 break;
3039                 revs->linear = p != NULL;
3040         }
3041         if (revs->reverse) {
3042                 if (revs->linear)
3043                         commit->object.flags |= TRACK_LINEAR;
3044         }
3045         free_commit_list(revs->previous_parents);
3046         revs->previous_parents = copy_commit_list(commit->parents);
3047 }
3048
3049 static struct commit *get_revision_1(struct rev_info *revs)
3050 {
3051         if (!revs->commits)
3052                 return NULL;
3053
3054         do {
3055                 struct commit *commit = pop_commit(&revs->commits);
3056
3057                 if (revs->reflog_info) {
3058                         save_parents(revs, commit);
3059                         fake_reflog_parent(revs->reflog_info, commit);
3060                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
3061                 }
3062
3063                 /*
3064                  * If we haven't done the list limiting, we need to look at
3065                  * the parents here. We also need to do the date-based limiting
3066                  * that we'd otherwise have done in limit_list().
3067                  */
3068                 if (!revs->limited) {
3069                         if (revs->max_age != -1 &&
3070                             (commit->date < revs->max_age))
3071                                 continue;
3072                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0) {
3073                                 if (!revs->ignore_missing_links)
3074                                         die("Failed to traverse parents of commit %s",
3075                                                 oid_to_hex(&commit->object.oid));
3076                         }
3077                 }
3078
3079                 switch (simplify_commit(revs, commit)) {
3080                 case commit_ignore:
3081                         continue;
3082                 case commit_error:
3083                         die("Failed to simplify parents of commit %s",
3084                             oid_to_hex(&commit->object.oid));
3085                 default:
3086                         if (revs->track_linear)
3087                                 track_linear(revs, commit);
3088                         return commit;
3089                 }
3090         } while (revs->commits);
3091         return NULL;
3092 }
3093
3094 /*
3095  * Return true for entries that have not yet been shown.  (This is an
3096  * object_array_each_func_t.)
3097  */
3098 static int entry_unshown(struct object_array_entry *entry, void *cb_data_unused)
3099 {
3100         return !(entry->item->flags & SHOWN);
3101 }
3102
3103 /*
3104  * If array is on the verge of a realloc, garbage-collect any entries
3105  * that have already been shown to try to free up some space.
3106  */
3107 static void gc_boundary(struct object_array *array)
3108 {
3109         if (array->nr == array->alloc)
3110                 object_array_filter(array, entry_unshown, NULL);
3111 }
3112
3113 static void create_boundary_commit_list(struct rev_info *revs)
3114 {
3115         unsigned i;
3116         struct commit *c;
3117         struct object_array *array = &revs->boundary_commits;
3118         struct object_array_entry *objects = array->objects;
3119
3120         /*
3121          * If revs->commits is non-NULL at this point, an error occurred in
3122          * get_revision_1().  Ignore the error and continue printing the
3123          * boundary commits anyway.  (This is what the code has always
3124          * done.)
3125          */
3126         if (revs->commits) {
3127                 free_commit_list(revs->commits);
3128                 revs->commits = NULL;
3129         }
3130
3131         /*
3132          * Put all of the actual boundary commits from revs->boundary_commits
3133          * into revs->commits
3134          */
3135         for (i = 0; i < array->nr; i++) {
3136                 c = (struct commit *)(objects[i].item);
3137                 if (!c)
3138                         continue;
3139                 if (!(c->object.flags & CHILD_SHOWN))
3140                         continue;
3141                 if (c->object.flags & (SHOWN | BOUNDARY))
3142                         continue;
3143                 c->object.flags |= BOUNDARY;
3144                 commit_list_insert(c, &revs->commits);
3145         }
3146
3147         /*
3148          * If revs->topo_order is set, sort the boundary commits
3149          * in topological order
3150          */
3151         sort_in_topological_order(&revs->commits, revs->sort_order);
3152 }
3153
3154 static struct commit *get_revision_internal(struct rev_info *revs)
3155 {
3156         struct commit *c = NULL;
3157         struct commit_list *l;
3158
3159         if (revs->boundary == 2) {
3160                 /*
3161                  * All of the normal commits have already been returned,
3162                  * and we are now returning boundary commits.
3163                  * create_boundary_commit_list() has populated
3164                  * revs->commits with the remaining commits to return.
3165                  */
3166                 c = pop_commit(&revs->commits);
3167                 if (c)
3168                         c->object.flags |= SHOWN;
3169                 return c;
3170         }
3171
3172         /*
3173          * If our max_count counter has reached zero, then we are done. We
3174          * don't simply return NULL because we still might need to show
3175          * boundary commits. But we want to avoid calling get_revision_1, which
3176          * might do a considerable amount of work finding the next commit only
3177          * for us to throw it away.
3178          *
3179          * If it is non-zero, then either we don't have a max_count at all
3180          * (-1), or it is still counting, in which case we decrement.
3181          */
3182         if (revs->max_count) {
3183                 c = get_revision_1(revs);
3184                 if (c) {
3185                         while (revs->skip_count > 0) {
3186                                 revs->skip_count--;
3187                                 c = get_revision_1(revs);
3188                                 if (!c)
3189                                         break;
3190                         }
3191                 }
3192
3193                 if (revs->max_count > 0)
3194                         revs->max_count--;
3195         }
3196
3197         if (c)
3198                 c->object.flags |= SHOWN;
3199
3200         if (!revs->boundary)
3201                 return c;
3202
3203         if (!c) {
3204                 /*
3205                  * get_revision_1() runs out the commits, and
3206                  * we are done computing the boundaries.
3207                  * switch to boundary commits output mode.
3208                  */
3209                 revs->boundary = 2;
3210
3211                 /*
3212                  * Update revs->commits to contain the list of
3213                  * boundary commits.
3214                  */
3215                 create_boundary_commit_list(revs);
3216
3217                 return get_revision_internal(revs);
3218         }
3219
3220         /*
3221          * boundary commits are the commits that are parents of the
3222          * ones we got from get_revision_1() but they themselves are
3223          * not returned from get_revision_1().  Before returning
3224          * 'c', we need to mark its parents that they could be boundaries.
3225          */
3226
3227         for (l = c->parents; l; l = l->next) {
3228                 struct object *p;
3229                 p = &(l->item->object);
3230                 if (p->flags & (CHILD_SHOWN | SHOWN))
3231                         continue;
3232                 p->flags |= CHILD_SHOWN;
3233                 gc_boundary(&revs->boundary_commits);
3234                 add_object_array(p, NULL, &revs->boundary_commits);
3235         }
3236
3237         return c;
3238 }
3239
3240 struct commit *get_revision(struct rev_info *revs)
3241 {
3242         struct commit *c;
3243         struct commit_list *reversed;
3244
3245         if (revs->reverse) {
3246                 reversed = NULL;
3247                 while ((c = get_revision_internal(revs)))
3248                         commit_list_insert(c, &reversed);
3249                 revs->commits = reversed;
3250                 revs->reverse = 0;
3251                 revs->reverse_output_stage = 1;
3252         }
3253
3254         if (revs->reverse_output_stage) {
3255                 c = pop_commit(&revs->commits);
3256                 if (revs->track_linear)
3257                         revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
3258                 return c;
3259         }
3260
3261         c = get_revision_internal(revs);
3262         if (c && revs->graph)
3263                 graph_update(revs->graph, c);
3264         if (!c) {
3265                 free_saved_parents(revs);
3266                 if (revs->previous_parents) {
3267                         free_commit_list(revs->previous_parents);
3268                         revs->previous_parents = NULL;
3269                 }
3270         }
3271         return c;
3272 }
3273
3274 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
3275 {
3276         if (commit->object.flags & BOUNDARY)
3277                 return "-";
3278         else if (commit->object.flags & UNINTERESTING)
3279                 return "^";
3280         else if (commit->object.flags & PATCHSAME)
3281                 return "=";
3282         else if (!revs || revs->left_right) {
3283                 if (commit->object.flags & SYMMETRIC_LEFT)
3284                         return "<";
3285                 else
3286                         return ">";
3287         } else if (revs->graph)
3288                 return "*";
3289         else if (revs->cherry_mark)
3290                 return "+";
3291         return "";
3292 }
3293
3294 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
3295 {
3296         char *mark = get_revision_mark(revs, commit);
3297         if (!strlen(mark))
3298                 return;
3299         fputs(mark, stdout);
3300         putchar(' ');
3301 }