Merge branch '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
19 volatile show_early_output_fn_t show_early_output;
20
21 char *path_name(const struct name_path *path, const char *name)
22 {
23         const struct name_path *p;
24         char *n, *m;
25         int nlen = strlen(name);
26         int len = nlen + 1;
27
28         for (p = path; p; p = p->up) {
29                 if (p->elem_len)
30                         len += p->elem_len + 1;
31         }
32         n = xmalloc(len);
33         m = n + len - (nlen + 1);
34         strcpy(m, name);
35         for (p = path; p; p = p->up) {
36                 if (p->elem_len) {
37                         m -= p->elem_len + 1;
38                         memcpy(m, p->elem, p->elem_len);
39                         m[p->elem_len] = '/';
40                 }
41         }
42         return n;
43 }
44
45 static int show_path_component_truncated(FILE *out, const char *name, int len)
46 {
47         int cnt;
48         for (cnt = 0; cnt < len; cnt++) {
49                 int ch = name[cnt];
50                 if (!ch || ch == '\n')
51                         return -1;
52                 fputc(ch, out);
53         }
54         return len;
55 }
56
57 static int show_path_truncated(FILE *out, const struct name_path *path)
58 {
59         int emitted, ours;
60
61         if (!path)
62                 return 0;
63         emitted = show_path_truncated(out, path->up);
64         if (emitted < 0)
65                 return emitted;
66         if (emitted)
67                 fputc('/', out);
68         ours = show_path_component_truncated(out, path->elem, path->elem_len);
69         if (ours < 0)
70                 return ours;
71         return ours || emitted;
72 }
73
74 void show_object_with_name(FILE *out, struct object *obj,
75                            const struct name_path *path, const char *component)
76 {
77         struct name_path leaf;
78         leaf.up = (struct name_path *)path;
79         leaf.elem = component;
80         leaf.elem_len = strlen(component);
81
82         fprintf(out, "%s ", sha1_to_hex(obj->sha1));
83         show_path_truncated(out, &leaf);
84         fputc('\n', out);
85 }
86
87 void add_object(struct object *obj,
88                 struct object_array *p,
89                 struct name_path *path,
90                 const char *name)
91 {
92         char *pn = path_name(path, name);
93         add_object_array(obj, pn, p);
94         free(pn);
95 }
96
97 static void mark_blob_uninteresting(struct blob *blob)
98 {
99         if (!blob)
100                 return;
101         if (blob->object.flags & UNINTERESTING)
102                 return;
103         blob->object.flags |= UNINTERESTING;
104 }
105
106 void mark_tree_uninteresting(struct tree *tree)
107 {
108         struct tree_desc desc;
109         struct name_entry entry;
110         struct object *obj = &tree->object;
111
112         if (!tree)
113                 return;
114         if (obj->flags & UNINTERESTING)
115                 return;
116         obj->flags |= UNINTERESTING;
117         if (!has_sha1_file(obj->sha1))
118                 return;
119         if (parse_tree(tree) < 0)
120                 die("bad tree %s", sha1_to_hex(obj->sha1));
121
122         init_tree_desc(&desc, tree->buffer, tree->size);
123         while (tree_entry(&desc, &entry)) {
124                 switch (object_type(entry.mode)) {
125                 case OBJ_TREE:
126                         mark_tree_uninteresting(lookup_tree(entry.sha1));
127                         break;
128                 case OBJ_BLOB:
129                         mark_blob_uninteresting(lookup_blob(entry.sha1));
130                         break;
131                 default:
132                         /* Subproject commit - not in this repository */
133                         break;
134                 }
135         }
136
137         /*
138          * We don't care about the tree any more
139          * after it has been marked uninteresting.
140          */
141         free(tree->buffer);
142         tree->buffer = NULL;
143 }
144
145 void mark_parents_uninteresting(struct commit *commit)
146 {
147         struct commit_list *parents = NULL, *l;
148
149         for (l = commit->parents; l; l = l->next)
150                 commit_list_insert(l->item, &parents);
151
152         while (parents) {
153                 struct commit *commit = parents->item;
154                 l = parents;
155                 parents = parents->next;
156                 free(l);
157
158                 while (commit) {
159                         /*
160                          * A missing commit is ok iff its parent is marked
161                          * uninteresting.
162                          *
163                          * We just mark such a thing parsed, so that when
164                          * it is popped next time around, we won't be trying
165                          * to parse it and get an error.
166                          */
167                         if (!has_sha1_file(commit->object.sha1))
168                                 commit->object.parsed = 1;
169
170                         if (commit->object.flags & UNINTERESTING)
171                                 break;
172
173                         commit->object.flags |= UNINTERESTING;
174
175                         /*
176                          * Normally we haven't parsed the parent
177                          * yet, so we won't have a parent of a parent
178                          * here. However, it may turn out that we've
179                          * reached this commit some other way (where it
180                          * wasn't uninteresting), in which case we need
181                          * to mark its parents recursively too..
182                          */
183                         if (!commit->parents)
184                                 break;
185
186                         for (l = commit->parents->next; l; l = l->next)
187                                 commit_list_insert(l->item, &parents);
188                         commit = commit->parents->item;
189                 }
190         }
191 }
192
193 static void add_pending_object_with_mode(struct rev_info *revs,
194                                          struct object *obj,
195                                          const char *name, unsigned mode)
196 {
197         if (!obj)
198                 return;
199         if (revs->no_walk && (obj->flags & UNINTERESTING))
200                 revs->no_walk = 0;
201         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
202                 struct strbuf buf = STRBUF_INIT;
203                 int len = interpret_branch_name(name, &buf);
204                 int st;
205
206                 if (0 < len && name[len] && buf.len)
207                         strbuf_addstr(&buf, name + len);
208                 st = add_reflog_for_walk(revs->reflog_info,
209                                          (struct commit *)obj,
210                                          buf.buf[0] ? buf.buf: name);
211                 strbuf_release(&buf);
212                 if (st)
213                         return;
214         }
215         add_object_array_with_mode(obj, name, &revs->pending, mode);
216 }
217
218 void add_pending_object(struct rev_info *revs,
219                         struct object *obj, const char *name)
220 {
221         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
222 }
223
224 void add_head_to_pending(struct rev_info *revs)
225 {
226         unsigned char sha1[20];
227         struct object *obj;
228         if (get_sha1("HEAD", sha1))
229                 return;
230         obj = parse_object(sha1);
231         if (!obj)
232                 return;
233         add_pending_object(revs, obj, "HEAD");
234 }
235
236 static struct object *get_reference(struct rev_info *revs, const char *name,
237                                     const unsigned char *sha1,
238                                     unsigned int flags)
239 {
240         struct object *object;
241
242         object = parse_object(sha1);
243         if (!object) {
244                 if (revs->ignore_missing)
245                         return object;
246                 die("bad object %s", name);
247         }
248         object->flags |= flags;
249         return object;
250 }
251
252 void add_pending_sha1(struct rev_info *revs, const char *name,
253                       const unsigned char *sha1, unsigned int flags)
254 {
255         struct object *object = get_reference(revs, name, sha1, flags);
256         add_pending_object(revs, object, name);
257 }
258
259 static struct commit *handle_commit(struct rev_info *revs,
260                                     struct object *object, const char *name)
261 {
262         unsigned long flags = object->flags;
263
264         /*
265          * Tag object? Look what it points to..
266          */
267         while (object->type == OBJ_TAG) {
268                 struct tag *tag = (struct tag *) object;
269                 if (revs->tag_objects && !(flags & UNINTERESTING))
270                         add_pending_object(revs, object, tag->tag);
271                 if (!tag->tagged)
272                         die("bad tag");
273                 object = parse_object(tag->tagged->sha1);
274                 if (!object) {
275                         if (flags & UNINTERESTING)
276                                 return NULL;
277                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
278                 }
279         }
280
281         /*
282          * Commit object? Just return it, we'll do all the complex
283          * reachability crud.
284          */
285         if (object->type == OBJ_COMMIT) {
286                 struct commit *commit = (struct commit *)object;
287                 if (parse_commit(commit) < 0)
288                         die("unable to parse commit %s", name);
289                 if (flags & UNINTERESTING) {
290                         commit->object.flags |= UNINTERESTING;
291                         mark_parents_uninteresting(commit);
292                         revs->limited = 1;
293                 }
294                 if (revs->show_source && !commit->util)
295                         commit->util = (void *) name;
296                 return commit;
297         }
298
299         /*
300          * Tree object? Either mark it uninteresting, or add it
301          * to the list of objects to look at later..
302          */
303         if (object->type == OBJ_TREE) {
304                 struct tree *tree = (struct tree *)object;
305                 if (!revs->tree_objects)
306                         return NULL;
307                 if (flags & UNINTERESTING) {
308                         mark_tree_uninteresting(tree);
309                         return NULL;
310                 }
311                 add_pending_object(revs, object, "");
312                 return NULL;
313         }
314
315         /*
316          * Blob object? You know the drill by now..
317          */
318         if (object->type == OBJ_BLOB) {
319                 struct blob *blob = (struct blob *)object;
320                 if (!revs->blob_objects)
321                         return NULL;
322                 if (flags & UNINTERESTING) {
323                         mark_blob_uninteresting(blob);
324                         return NULL;
325                 }
326                 add_pending_object(revs, object, "");
327                 return NULL;
328         }
329         die("%s is unknown object", name);
330 }
331
332 static int everybody_uninteresting(struct commit_list *orig)
333 {
334         struct commit_list *list = orig;
335         while (list) {
336                 struct commit *commit = list->item;
337                 list = list->next;
338                 if (commit->object.flags & UNINTERESTING)
339                         continue;
340                 return 0;
341         }
342         return 1;
343 }
344
345 /*
346  * A definition of "relevant" commit that we can use to simplify limited graphs
347  * by eliminating side branches.
348  *
349  * A "relevant" commit is one that is !UNINTERESTING (ie we are including it
350  * in our list), or that is a specified BOTTOM commit. Then after computing
351  * a limited list, during processing we can generally ignore boundary merges
352  * coming from outside the graph, (ie from irrelevant parents), and treat
353  * those merges as if they were single-parent. TREESAME is defined to consider
354  * only relevant parents, if any. If we are TREESAME to our on-graph parents,
355  * we don't care if we were !TREESAME to non-graph parents.
356  *
357  * Treating bottom commits as relevant ensures that a limited graph's
358  * connection to the actual bottom commit is not viewed as a side branch, but
359  * treated as part of the graph. For example:
360  *
361  *   ....Z...A---X---o---o---B
362  *        .     /
363  *         W---Y
364  *
365  * When computing "A..B", the A-X connection is at least as important as
366  * Y-X, despite A being flagged UNINTERESTING.
367  *
368  * And when computing --ancestry-path "A..B", the A-X connection is more
369  * important than Y-X, despite both A and Y being flagged UNINTERESTING.
370  */
371 static inline int relevant_commit(struct commit *commit)
372 {
373         return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
374 }
375
376 /*
377  * Return a single relevant commit from a parent list. If we are a TREESAME
378  * commit, and this selects one of our parents, then we can safely simplify to
379  * that parent.
380  */
381 static struct commit *one_relevant_parent(const struct rev_info *revs,
382                                           struct commit_list *orig)
383 {
384         struct commit_list *list = orig;
385         struct commit *relevant = NULL;
386
387         if (!orig)
388                 return NULL;
389
390         /*
391          * For 1-parent commits, or if first-parent-only, then return that
392          * first parent (even if not "relevant" by the above definition).
393          * TREESAME will have been set purely on that parent.
394          */
395         if (revs->first_parent_only || !orig->next)
396                 return orig->item;
397
398         /*
399          * For multi-parent commits, identify a sole relevant parent, if any.
400          * If we have only one relevant parent, then TREESAME will be set purely
401          * with regard to that parent, and we can simplify accordingly.
402          *
403          * If we have more than one relevant parent, or no relevant parents
404          * (and multiple irrelevant ones), then we can't select a parent here
405          * and return NULL.
406          */
407         while (list) {
408                 struct commit *commit = list->item;
409                 list = list->next;
410                 if (relevant_commit(commit)) {
411                         if (relevant)
412                                 return NULL;
413                         relevant = commit;
414                 }
415         }
416         return relevant;
417 }
418
419 /*
420  * The goal is to get REV_TREE_NEW as the result only if the
421  * diff consists of all '+' (and no other changes), REV_TREE_OLD
422  * if the whole diff is removal of old data, and otherwise
423  * REV_TREE_DIFFERENT (of course if the trees are the same we
424  * want REV_TREE_SAME).
425  * That means that once we get to REV_TREE_DIFFERENT, we do not
426  * have to look any further.
427  */
428 static int tree_difference = REV_TREE_SAME;
429
430 static void file_add_remove(struct diff_options *options,
431                     int addremove, unsigned mode,
432                     const unsigned char *sha1,
433                     int sha1_valid,
434                     const char *fullpath, unsigned dirty_submodule)
435 {
436         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
437
438         tree_difference |= diff;
439         if (tree_difference == REV_TREE_DIFFERENT)
440                 DIFF_OPT_SET(options, HAS_CHANGES);
441 }
442
443 static void file_change(struct diff_options *options,
444                  unsigned old_mode, unsigned new_mode,
445                  const unsigned char *old_sha1,
446                  const unsigned char *new_sha1,
447                  int old_sha1_valid, int new_sha1_valid,
448                  const char *fullpath,
449                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
450 {
451         tree_difference = REV_TREE_DIFFERENT;
452         DIFF_OPT_SET(options, HAS_CHANGES);
453 }
454
455 static int rev_compare_tree(struct rev_info *revs,
456                             struct commit *parent, struct commit *commit)
457 {
458         struct tree *t1 = parent->tree;
459         struct tree *t2 = commit->tree;
460
461         if (!t1)
462                 return REV_TREE_NEW;
463         if (!t2)
464                 return REV_TREE_OLD;
465
466         if (revs->simplify_by_decoration) {
467                 /*
468                  * If we are simplifying by decoration, then the commit
469                  * is worth showing if it has a tag pointing at it.
470                  */
471                 if (lookup_decoration(&name_decoration, &commit->object))
472                         return REV_TREE_DIFFERENT;
473                 /*
474                  * A commit that is not pointed by a tag is uninteresting
475                  * if we are not limited by path.  This means that you will
476                  * see the usual "commits that touch the paths" plus any
477                  * tagged commit by specifying both --simplify-by-decoration
478                  * and pathspec.
479                  */
480                 if (!revs->prune_data.nr)
481                         return REV_TREE_SAME;
482         }
483
484         tree_difference = REV_TREE_SAME;
485         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
486         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
487                            &revs->pruning) < 0)
488                 return REV_TREE_DIFFERENT;
489         return tree_difference;
490 }
491
492 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
493 {
494         int retval;
495         void *tree;
496         unsigned long size;
497         struct tree_desc empty, real;
498         struct tree *t1 = commit->tree;
499
500         if (!t1)
501                 return 0;
502
503         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
504         if (!tree)
505                 return 0;
506         init_tree_desc(&real, tree, size);
507         init_tree_desc(&empty, "", 0);
508
509         tree_difference = REV_TREE_SAME;
510         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
511         retval = diff_tree(&empty, &real, "", &revs->pruning);
512         free(tree);
513
514         return retval >= 0 && (tree_difference == REV_TREE_SAME);
515 }
516
517 struct treesame_state {
518         unsigned int nparents;
519         unsigned char treesame[FLEX_ARRAY];
520 };
521
522 static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
523 {
524         unsigned n = commit_list_count(commit->parents);
525         struct treesame_state *st = xcalloc(1, sizeof(*st) + n);
526         st->nparents = n;
527         add_decoration(&revs->treesame, &commit->object, st);
528         return st;
529 }
530
531 /*
532  * Must be called immediately after removing the nth_parent from a commit's
533  * parent list, if we are maintaining the per-parent treesame[] decoration.
534  * This does not recalculate the master TREESAME flag - update_treesame()
535  * should be called to update it after a sequence of treesame[] modifications
536  * that may have affected it.
537  */
538 static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
539 {
540         struct treesame_state *st;
541         int old_same;
542
543         if (!commit->parents) {
544                 /*
545                  * Have just removed the only parent from a non-merge.
546                  * Different handling, as we lack decoration.
547                  */
548                 if (nth_parent != 0)
549                         die("compact_treesame %u", nth_parent);
550                 old_same = !!(commit->object.flags & TREESAME);
551                 if (rev_same_tree_as_empty(revs, commit))
552                         commit->object.flags |= TREESAME;
553                 else
554                         commit->object.flags &= ~TREESAME;
555                 return old_same;
556         }
557
558         st = lookup_decoration(&revs->treesame, &commit->object);
559         if (!st || nth_parent >= st->nparents)
560                 die("compact_treesame %u", nth_parent);
561
562         old_same = st->treesame[nth_parent];
563         memmove(st->treesame + nth_parent,
564                 st->treesame + nth_parent + 1,
565                 st->nparents - nth_parent - 1);
566
567         /*
568          * If we've just become a non-merge commit, update TREESAME
569          * immediately, and remove the no-longer-needed decoration.
570          * If still a merge, defer update until update_treesame().
571          */
572         if (--st->nparents == 1) {
573                 if (commit->parents->next)
574                         die("compact_treesame parents mismatch");
575                 if (st->treesame[0] && revs->dense)
576                         commit->object.flags |= TREESAME;
577                 else
578                         commit->object.flags &= ~TREESAME;
579                 free(add_decoration(&revs->treesame, &commit->object, NULL));
580         }
581
582         return old_same;
583 }
584
585 static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
586 {
587         if (commit->parents && commit->parents->next) {
588                 unsigned n;
589                 struct treesame_state *st;
590                 struct commit_list *p;
591                 unsigned relevant_parents;
592                 unsigned relevant_change, irrelevant_change;
593
594                 st = lookup_decoration(&revs->treesame, &commit->object);
595                 if (!st)
596                         die("update_treesame %s", sha1_to_hex(commit->object.sha1));
597                 relevant_parents = 0;
598                 relevant_change = irrelevant_change = 0;
599                 for (p = commit->parents, n = 0; p; n++, p = p->next) {
600                         if (relevant_commit(p->item)) {
601                                 relevant_change |= !st->treesame[n];
602                                 relevant_parents++;
603                         } else
604                                 irrelevant_change |= !st->treesame[n];
605                 }
606                 if (relevant_parents ? relevant_change : irrelevant_change)
607                         commit->object.flags &= ~TREESAME;
608                 else
609                         commit->object.flags |= TREESAME;
610         }
611
612         return commit->object.flags & TREESAME;
613 }
614
615 static inline int limiting_can_increase_treesame(const struct rev_info *revs)
616 {
617         /*
618          * TREESAME is irrelevant unless prune && dense;
619          * if simplify_history is set, we can't have a mixture of TREESAME and
620          *    !TREESAME INTERESTING parents (and we don't have treesame[]
621          *    decoration anyway);
622          * if first_parent_only is set, then the TREESAME flag is locked
623          *    against the first parent (and again we lack treesame[] decoration).
624          */
625         return revs->prune && revs->dense &&
626                !revs->simplify_history &&
627                !revs->first_parent_only;
628 }
629
630 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
631 {
632         struct commit_list **pp, *parent;
633         struct treesame_state *ts = NULL;
634         int relevant_change = 0, irrelevant_change = 0;
635         int relevant_parents, nth_parent;
636
637         /*
638          * If we don't do pruning, everything is interesting
639          */
640         if (!revs->prune)
641                 return;
642
643         if (!commit->tree)
644                 return;
645
646         if (!commit->parents) {
647                 if (rev_same_tree_as_empty(revs, commit))
648                         commit->object.flags |= TREESAME;
649                 return;
650         }
651
652         /*
653          * Normal non-merge commit? If we don't want to make the
654          * history dense, we consider it always to be a change..
655          */
656         if (!revs->dense && !commit->parents->next)
657                 return;
658
659         for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
660              (parent = *pp) != NULL;
661              pp = &parent->next, nth_parent++) {
662                 struct commit *p = parent->item;
663                 if (relevant_commit(p))
664                         relevant_parents++;
665
666                 if (nth_parent == 1) {
667                         /*
668                          * This our second loop iteration - so we now know
669                          * we're dealing with a merge.
670                          *
671                          * Do not compare with later parents when we care only about
672                          * the first parent chain, in order to avoid derailing the
673                          * traversal to follow a side branch that brought everything
674                          * in the path we are limited to by the pathspec.
675                          */
676                         if (revs->first_parent_only)
677                                 break;
678                         /*
679                          * If this will remain a potentially-simplifiable
680                          * merge, remember per-parent treesame if needed.
681                          * Initialise the array with the comparison from our
682                          * first iteration.
683                          */
684                         if (revs->treesame.name &&
685                             !revs->simplify_history &&
686                             !(commit->object.flags & UNINTERESTING)) {
687                                 ts = initialise_treesame(revs, commit);
688                                 if (!(irrelevant_change || relevant_change))
689                                         ts->treesame[0] = 1;
690                         }
691                 }
692                 if (parse_commit(p) < 0)
693                         die("cannot simplify commit %s (because of %s)",
694                             sha1_to_hex(commit->object.sha1),
695                             sha1_to_hex(p->object.sha1));
696                 switch (rev_compare_tree(revs, p, commit)) {
697                 case REV_TREE_SAME:
698                         if (!revs->simplify_history || !relevant_commit(p)) {
699                                 /* Even if a merge with an uninteresting
700                                  * side branch brought the entire change
701                                  * we are interested in, we do not want
702                                  * to lose the other branches of this
703                                  * merge, so we just keep going.
704                                  */
705                                 if (ts)
706                                         ts->treesame[nth_parent] = 1;
707                                 continue;
708                         }
709                         parent->next = NULL;
710                         commit->parents = parent;
711                         commit->object.flags |= TREESAME;
712                         return;
713
714                 case REV_TREE_NEW:
715                         if (revs->remove_empty_trees &&
716                             rev_same_tree_as_empty(revs, p)) {
717                                 /* We are adding all the specified
718                                  * paths from this parent, so the
719                                  * history beyond this parent is not
720                                  * interesting.  Remove its parents
721                                  * (they are grandparents for us).
722                                  * IOW, we pretend this parent is a
723                                  * "root" commit.
724                                  */
725                                 if (parse_commit(p) < 0)
726                                         die("cannot simplify commit %s (invalid %s)",
727                                             sha1_to_hex(commit->object.sha1),
728                                             sha1_to_hex(p->object.sha1));
729                                 p->parents = NULL;
730                         }
731                 /* fallthrough */
732                 case REV_TREE_OLD:
733                 case REV_TREE_DIFFERENT:
734                         if (relevant_commit(p))
735                                 relevant_change = 1;
736                         else
737                                 irrelevant_change = 1;
738                         continue;
739                 }
740                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
741         }
742
743         /*
744          * TREESAME is straightforward for single-parent commits. For merge
745          * commits, it is most useful to define it so that "irrelevant"
746          * parents cannot make us !TREESAME - if we have any relevant
747          * parents, then we only consider TREESAMEness with respect to them,
748          * allowing irrelevant merges from uninteresting branches to be
749          * simplified away. Only if we have only irrelevant parents do we
750          * base TREESAME on them. Note that this logic is replicated in
751          * update_treesame, which should be kept in sync.
752          */
753         if (relevant_parents ? !relevant_change : !irrelevant_change)
754                 commit->object.flags |= TREESAME;
755 }
756
757 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
758                     struct commit_list *cached_base, struct commit_list **cache)
759 {
760         struct commit_list *new_entry;
761
762         if (cached_base && p->date < cached_base->item->date)
763                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
764         else
765                 new_entry = commit_list_insert_by_date(p, head);
766
767         if (cache && (!*cache || p->date < (*cache)->item->date))
768                 *cache = new_entry;
769 }
770
771 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
772                     struct commit_list **list, struct commit_list **cache_ptr)
773 {
774         struct commit_list *parent = commit->parents;
775         unsigned left_flag;
776         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
777
778         if (commit->object.flags & ADDED)
779                 return 0;
780         commit->object.flags |= ADDED;
781
782         /*
783          * If the commit is uninteresting, don't try to
784          * prune parents - we want the maximal uninteresting
785          * set.
786          *
787          * Normally we haven't parsed the parent
788          * yet, so we won't have a parent of a parent
789          * here. However, it may turn out that we've
790          * reached this commit some other way (where it
791          * wasn't uninteresting), in which case we need
792          * to mark its parents recursively too..
793          */
794         if (commit->object.flags & UNINTERESTING) {
795                 while (parent) {
796                         struct commit *p = parent->item;
797                         parent = parent->next;
798                         if (p)
799                                 p->object.flags |= UNINTERESTING;
800                         if (parse_commit(p) < 0)
801                                 continue;
802                         if (p->parents)
803                                 mark_parents_uninteresting(p);
804                         if (p->object.flags & SEEN)
805                                 continue;
806                         p->object.flags |= SEEN;
807                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
808                 }
809                 return 0;
810         }
811
812         /*
813          * Ok, the commit wasn't uninteresting. Try to
814          * simplify the commit history and find the parent
815          * that has no differences in the path set if one exists.
816          */
817         try_to_simplify_commit(revs, commit);
818
819         if (revs->no_walk)
820                 return 0;
821
822         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
823
824         for (parent = commit->parents; parent; parent = parent->next) {
825                 struct commit *p = parent->item;
826
827                 if (parse_commit(p) < 0)
828                         return -1;
829                 if (revs->show_source && !p->util)
830                         p->util = commit->util;
831                 p->object.flags |= left_flag;
832                 if (!(p->object.flags & SEEN)) {
833                         p->object.flags |= SEEN;
834                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
835                 }
836                 if (revs->first_parent_only)
837                         break;
838         }
839         return 0;
840 }
841
842 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
843 {
844         struct commit_list *p;
845         int left_count = 0, right_count = 0;
846         int left_first;
847         struct patch_ids ids;
848         unsigned cherry_flag;
849
850         /* First count the commits on the left and on the right */
851         for (p = list; p; p = p->next) {
852                 struct commit *commit = p->item;
853                 unsigned flags = commit->object.flags;
854                 if (flags & BOUNDARY)
855                         ;
856                 else if (flags & SYMMETRIC_LEFT)
857                         left_count++;
858                 else
859                         right_count++;
860         }
861
862         if (!left_count || !right_count)
863                 return;
864
865         left_first = left_count < right_count;
866         init_patch_ids(&ids);
867         ids.diffopts.pathspec = revs->diffopt.pathspec;
868
869         /* Compute patch-ids for one side */
870         for (p = list; p; p = p->next) {
871                 struct commit *commit = p->item;
872                 unsigned flags = commit->object.flags;
873
874                 if (flags & BOUNDARY)
875                         continue;
876                 /*
877                  * If we have fewer left, left_first is set and we omit
878                  * commits on the right branch in this loop.  If we have
879                  * fewer right, we skip the left ones.
880                  */
881                 if (left_first != !!(flags & SYMMETRIC_LEFT))
882                         continue;
883                 commit->util = add_commit_patch_id(commit, &ids);
884         }
885
886         /* either cherry_mark or cherry_pick are true */
887         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
888
889         /* Check the other side */
890         for (p = list; p; p = p->next) {
891                 struct commit *commit = p->item;
892                 struct patch_id *id;
893                 unsigned flags = commit->object.flags;
894
895                 if (flags & BOUNDARY)
896                         continue;
897                 /*
898                  * If we have fewer left, left_first is set and we omit
899                  * commits on the left branch in this loop.
900                  */
901                 if (left_first == !!(flags & SYMMETRIC_LEFT))
902                         continue;
903
904                 /*
905                  * Have we seen the same patch id?
906                  */
907                 id = has_commit_patch_id(commit, &ids);
908                 if (!id)
909                         continue;
910                 id->seen = 1;
911                 commit->object.flags |= cherry_flag;
912         }
913
914         /* Now check the original side for seen ones */
915         for (p = list; p; p = p->next) {
916                 struct commit *commit = p->item;
917                 struct patch_id *ent;
918
919                 ent = commit->util;
920                 if (!ent)
921                         continue;
922                 if (ent->seen)
923                         commit->object.flags |= cherry_flag;
924                 commit->util = NULL;
925         }
926
927         free_patch_ids(&ids);
928 }
929
930 /* How many extra uninteresting commits we want to see.. */
931 #define SLOP 5
932
933 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
934 {
935         /*
936          * No source list at all? We're definitely done..
937          */
938         if (!src)
939                 return 0;
940
941         /*
942          * Does the destination list contain entries with a date
943          * before the source list? Definitely _not_ done.
944          */
945         if (date <= src->item->date)
946                 return SLOP;
947
948         /*
949          * Does the source list still have interesting commits in
950          * it? Definitely not done..
951          */
952         if (!everybody_uninteresting(src))
953                 return SLOP;
954
955         /* Ok, we're closing in.. */
956         return slop-1;
957 }
958
959 /*
960  * "rev-list --ancestry-path A..B" computes commits that are ancestors
961  * of B but not ancestors of A but further limits the result to those
962  * that are descendants of A.  This takes the list of bottom commits and
963  * the result of "A..B" without --ancestry-path, and limits the latter
964  * further to the ones that can reach one of the commits in "bottom".
965  */
966 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
967 {
968         struct commit_list *p;
969         struct commit_list *rlist = NULL;
970         int made_progress;
971
972         /*
973          * Reverse the list so that it will be likely that we would
974          * process parents before children.
975          */
976         for (p = list; p; p = p->next)
977                 commit_list_insert(p->item, &rlist);
978
979         for (p = bottom; p; p = p->next)
980                 p->item->object.flags |= TMP_MARK;
981
982         /*
983          * Mark the ones that can reach bottom commits in "list",
984          * in a bottom-up fashion.
985          */
986         do {
987                 made_progress = 0;
988                 for (p = rlist; p; p = p->next) {
989                         struct commit *c = p->item;
990                         struct commit_list *parents;
991                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
992                                 continue;
993                         for (parents = c->parents;
994                              parents;
995                              parents = parents->next) {
996                                 if (!(parents->item->object.flags & TMP_MARK))
997                                         continue;
998                                 c->object.flags |= TMP_MARK;
999                                 made_progress = 1;
1000                                 break;
1001                         }
1002                 }
1003         } while (made_progress);
1004
1005         /*
1006          * NEEDSWORK: decide if we want to remove parents that are
1007          * not marked with TMP_MARK from commit->parents for commits
1008          * in the resulting list.  We may not want to do that, though.
1009          */
1010
1011         /*
1012          * The ones that are not marked with TMP_MARK are uninteresting
1013          */
1014         for (p = list; p; p = p->next) {
1015                 struct commit *c = p->item;
1016                 if (c->object.flags & TMP_MARK)
1017                         continue;
1018                 c->object.flags |= UNINTERESTING;
1019         }
1020
1021         /* We are done with the TMP_MARK */
1022         for (p = list; p; p = p->next)
1023                 p->item->object.flags &= ~TMP_MARK;
1024         for (p = bottom; p; p = p->next)
1025                 p->item->object.flags &= ~TMP_MARK;
1026         free_commit_list(rlist);
1027 }
1028
1029 /*
1030  * Before walking the history, keep the set of "negative" refs the
1031  * caller has asked to exclude.
1032  *
1033  * This is used to compute "rev-list --ancestry-path A..B", as we need
1034  * to filter the result of "A..B" further to the ones that can actually
1035  * reach A.
1036  */
1037 static struct commit_list *collect_bottom_commits(struct commit_list *list)
1038 {
1039         struct commit_list *elem, *bottom = NULL;
1040         for (elem = list; elem; elem = elem->next)
1041                 if (elem->item->object.flags & BOTTOM)
1042                         commit_list_insert(elem->item, &bottom);
1043         return bottom;
1044 }
1045
1046 /* Assumes either left_only or right_only is set */
1047 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
1048 {
1049         struct commit_list *p;
1050
1051         for (p = list; p; p = p->next) {
1052                 struct commit *commit = p->item;
1053
1054                 if (revs->right_only) {
1055                         if (commit->object.flags & SYMMETRIC_LEFT)
1056                                 commit->object.flags |= SHOWN;
1057                 } else  /* revs->left_only is set */
1058                         if (!(commit->object.flags & SYMMETRIC_LEFT))
1059                                 commit->object.flags |= SHOWN;
1060         }
1061 }
1062
1063 static int limit_list(struct rev_info *revs)
1064 {
1065         int slop = SLOP;
1066         unsigned long date = ~0ul;
1067         struct commit_list *list = revs->commits;
1068         struct commit_list *newlist = NULL;
1069         struct commit_list **p = &newlist;
1070         struct commit_list *bottom = NULL;
1071
1072         if (revs->ancestry_path) {
1073                 bottom = collect_bottom_commits(list);
1074                 if (!bottom)
1075                         die("--ancestry-path given but there are no bottom commits");
1076         }
1077
1078         while (list) {
1079                 struct commit_list *entry = list;
1080                 struct commit *commit = list->item;
1081                 struct object *obj = &commit->object;
1082                 show_early_output_fn_t show;
1083
1084                 list = list->next;
1085                 free(entry);
1086
1087                 if (revs->max_age != -1 && (commit->date < revs->max_age))
1088                         obj->flags |= UNINTERESTING;
1089                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
1090                         return -1;
1091                 if (obj->flags & UNINTERESTING) {
1092                         mark_parents_uninteresting(commit);
1093                         if (revs->show_all)
1094                                 p = &commit_list_insert(commit, p)->next;
1095                         slop = still_interesting(list, date, slop);
1096                         if (slop)
1097                                 continue;
1098                         /* If showing all, add the whole pending list to the end */
1099                         if (revs->show_all)
1100                                 *p = list;
1101                         break;
1102                 }
1103                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1104                         continue;
1105                 date = commit->date;
1106                 p = &commit_list_insert(commit, p)->next;
1107
1108                 show = show_early_output;
1109                 if (!show)
1110                         continue;
1111
1112                 show(revs, newlist);
1113                 show_early_output = NULL;
1114         }
1115         if (revs->cherry_pick || revs->cherry_mark)
1116                 cherry_pick_list(newlist, revs);
1117
1118         if (revs->left_only || revs->right_only)
1119                 limit_left_right(newlist, revs);
1120
1121         if (bottom) {
1122                 limit_to_ancestry(bottom, newlist);
1123                 free_commit_list(bottom);
1124         }
1125
1126         /*
1127          * Check if any commits have become TREESAME by some of their parents
1128          * becoming UNINTERESTING.
1129          */
1130         if (limiting_can_increase_treesame(revs))
1131                 for (list = newlist; list; list = list->next) {
1132                         struct commit *c = list->item;
1133                         if (c->object.flags & (UNINTERESTING | TREESAME))
1134                                 continue;
1135                         update_treesame(revs, c);
1136                 }
1137
1138         revs->commits = newlist;
1139         return 0;
1140 }
1141
1142 /*
1143  * Add an entry to refs->cmdline with the specified information.
1144  * *name is copied.
1145  */
1146 static void add_rev_cmdline(struct rev_info *revs,
1147                             struct object *item,
1148                             const char *name,
1149                             int whence,
1150                             unsigned flags)
1151 {
1152         struct rev_cmdline_info *info = &revs->cmdline;
1153         int nr = info->nr;
1154
1155         ALLOC_GROW(info->rev, nr + 1, info->alloc);
1156         info->rev[nr].item = item;
1157         info->rev[nr].name = xstrdup(name);
1158         info->rev[nr].whence = whence;
1159         info->rev[nr].flags = flags;
1160         info->nr++;
1161 }
1162
1163 static void add_rev_cmdline_list(struct rev_info *revs,
1164                                  struct commit_list *commit_list,
1165                                  int whence,
1166                                  unsigned flags)
1167 {
1168         while (commit_list) {
1169                 struct object *object = &commit_list->item->object;
1170                 add_rev_cmdline(revs, object, sha1_to_hex(object->sha1),
1171                                 whence, flags);
1172                 commit_list = commit_list->next;
1173         }
1174 }
1175
1176 struct all_refs_cb {
1177         int all_flags;
1178         int warned_bad_reflog;
1179         struct rev_info *all_revs;
1180         const char *name_for_errormsg;
1181 };
1182
1183 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
1184 {
1185         struct all_refs_cb *cb = cb_data;
1186         struct object *object = get_reference(cb->all_revs, path, sha1,
1187                                               cb->all_flags);
1188         add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
1189         add_pending_sha1(cb->all_revs, path, sha1, cb->all_flags);
1190         return 0;
1191 }
1192
1193 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
1194         unsigned flags)
1195 {
1196         cb->all_revs = revs;
1197         cb->all_flags = flags;
1198 }
1199
1200 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
1201                 int (*for_each)(const char *, each_ref_fn, void *))
1202 {
1203         struct all_refs_cb cb;
1204         init_all_refs_cb(&cb, revs, flags);
1205         for_each(submodule, handle_one_ref, &cb);
1206 }
1207
1208 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
1209 {
1210         struct all_refs_cb *cb = cb_data;
1211         if (!is_null_sha1(sha1)) {
1212                 struct object *o = parse_object(sha1);
1213                 if (o) {
1214                         o->flags |= cb->all_flags;
1215                         /* ??? CMDLINEFLAGS ??? */
1216                         add_pending_object(cb->all_revs, o, "");
1217                 }
1218                 else if (!cb->warned_bad_reflog) {
1219                         warning("reflog of '%s' references pruned commits",
1220                                 cb->name_for_errormsg);
1221                         cb->warned_bad_reflog = 1;
1222                 }
1223         }
1224 }
1225
1226 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
1227                 const char *email, unsigned long timestamp, int tz,
1228                 const char *message, void *cb_data)
1229 {
1230         handle_one_reflog_commit(osha1, cb_data);
1231         handle_one_reflog_commit(nsha1, cb_data);
1232         return 0;
1233 }
1234
1235 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
1236 {
1237         struct all_refs_cb *cb = cb_data;
1238         cb->warned_bad_reflog = 0;
1239         cb->name_for_errormsg = path;
1240         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
1241         return 0;
1242 }
1243
1244 static void handle_reflog(struct rev_info *revs, unsigned flags)
1245 {
1246         struct all_refs_cb cb;
1247         cb.all_revs = revs;
1248         cb.all_flags = flags;
1249         for_each_reflog(handle_one_reflog, &cb);
1250 }
1251
1252 static int add_parents_only(struct rev_info *revs, const char *arg_, int flags)
1253 {
1254         unsigned char sha1[20];
1255         struct object *it;
1256         struct commit *commit;
1257         struct commit_list *parents;
1258         const char *arg = arg_;
1259
1260         if (*arg == '^') {
1261                 flags ^= UNINTERESTING | BOTTOM;
1262                 arg++;
1263         }
1264         if (get_sha1_committish(arg, sha1))
1265                 return 0;
1266         while (1) {
1267                 it = get_reference(revs, arg, sha1, 0);
1268                 if (!it && revs->ignore_missing)
1269                         return 0;
1270                 if (it->type != OBJ_TAG)
1271                         break;
1272                 if (!((struct tag*)it)->tagged)
1273                         return 0;
1274                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
1275         }
1276         if (it->type != OBJ_COMMIT)
1277                 return 0;
1278         commit = (struct commit *)it;
1279         for (parents = commit->parents; parents; parents = parents->next) {
1280                 it = &parents->item->object;
1281                 it->flags |= flags;
1282                 add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
1283                 add_pending_object(revs, it, arg);
1284         }
1285         return 1;
1286 }
1287
1288 void init_revisions(struct rev_info *revs, const char *prefix)
1289 {
1290         memset(revs, 0, sizeof(*revs));
1291
1292         revs->abbrev = DEFAULT_ABBREV;
1293         revs->ignore_merges = 1;
1294         revs->simplify_history = 1;
1295         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
1296         DIFF_OPT_SET(&revs->pruning, QUICK);
1297         revs->pruning.add_remove = file_add_remove;
1298         revs->pruning.change = file_change;
1299         revs->lifo = 1;
1300         revs->dense = 1;
1301         revs->prefix = prefix;
1302         revs->max_age = -1;
1303         revs->min_age = -1;
1304         revs->skip_count = -1;
1305         revs->max_count = -1;
1306         revs->max_parents = -1;
1307
1308         revs->commit_format = CMIT_FMT_DEFAULT;
1309
1310         init_grep_defaults();
1311         grep_init(&revs->grep_filter, prefix);
1312         revs->grep_filter.status_only = 1;
1313         revs->grep_filter.regflags = REG_NEWLINE;
1314
1315         diff_setup(&revs->diffopt);
1316         if (prefix && !revs->diffopt.prefix) {
1317                 revs->diffopt.prefix = prefix;
1318                 revs->diffopt.prefix_length = strlen(prefix);
1319         }
1320
1321         revs->notes_opt.use_default_notes = -1;
1322 }
1323
1324 static void add_pending_commit_list(struct rev_info *revs,
1325                                     struct commit_list *commit_list,
1326                                     unsigned int flags)
1327 {
1328         while (commit_list) {
1329                 struct object *object = &commit_list->item->object;
1330                 object->flags |= flags;
1331                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
1332                 commit_list = commit_list->next;
1333         }
1334 }
1335
1336 static void prepare_show_merge(struct rev_info *revs)
1337 {
1338         struct commit_list *bases;
1339         struct commit *head, *other;
1340         unsigned char sha1[20];
1341         const char **prune = NULL;
1342         int i, prune_num = 1; /* counting terminating NULL */
1343
1344         if (get_sha1("HEAD", sha1))
1345                 die("--merge without HEAD?");
1346         head = lookup_commit_or_die(sha1, "HEAD");
1347         if (get_sha1("MERGE_HEAD", sha1))
1348                 die("--merge without MERGE_HEAD?");
1349         other = lookup_commit_or_die(sha1, "MERGE_HEAD");
1350         add_pending_object(revs, &head->object, "HEAD");
1351         add_pending_object(revs, &other->object, "MERGE_HEAD");
1352         bases = get_merge_bases(head, other, 1);
1353         add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
1354         add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
1355         free_commit_list(bases);
1356         head->object.flags |= SYMMETRIC_LEFT;
1357
1358         if (!active_nr)
1359                 read_cache();
1360         for (i = 0; i < active_nr; i++) {
1361                 struct cache_entry *ce = active_cache[i];
1362                 if (!ce_stage(ce))
1363                         continue;
1364                 if (ce_path_match(ce, &revs->prune_data)) {
1365                         prune_num++;
1366                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
1367                         prune[prune_num-2] = ce->name;
1368                         prune[prune_num-1] = NULL;
1369                 }
1370                 while ((i+1 < active_nr) &&
1371                        ce_same_name(ce, active_cache[i+1]))
1372                         i++;
1373         }
1374         free_pathspec(&revs->prune_data);
1375         init_pathspec(&revs->prune_data, prune);
1376         revs->limited = 1;
1377 }
1378
1379 int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
1380 {
1381         struct object_context oc;
1382         char *dotdot;
1383         struct object *object;
1384         unsigned char sha1[20];
1385         int local_flags;
1386         const char *arg = arg_;
1387         int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
1388         unsigned get_sha1_flags = 0;
1389
1390         flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
1391
1392         dotdot = strstr(arg, "..");
1393         if (dotdot) {
1394                 unsigned char from_sha1[20];
1395                 const char *next = dotdot + 2;
1396                 const char *this = arg;
1397                 int symmetric = *next == '.';
1398                 unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
1399                 static const char head_by_default[] = "HEAD";
1400                 unsigned int a_flags;
1401
1402                 *dotdot = 0;
1403                 next += symmetric;
1404
1405                 if (!*next)
1406                         next = head_by_default;
1407                 if (dotdot == arg)
1408                         this = head_by_default;
1409                 if (this == head_by_default && next == head_by_default &&
1410                     !symmetric) {
1411                         /*
1412                          * Just ".."?  That is not a range but the
1413                          * pathspec for the parent directory.
1414                          */
1415                         if (!cant_be_filename) {
1416                                 *dotdot = '.';
1417                                 return -1;
1418                         }
1419                 }
1420                 if (!get_sha1_committish(this, from_sha1) &&
1421                     !get_sha1_committish(next, sha1)) {
1422                         struct commit *a, *b;
1423                         struct commit_list *exclude;
1424
1425                         a = lookup_commit_reference(from_sha1);
1426                         b = lookup_commit_reference(sha1);
1427                         if (!a || !b) {
1428                                 if (revs->ignore_missing)
1429                                         return 0;
1430                                 die(symmetric ?
1431                                     "Invalid symmetric difference expression %s...%s" :
1432                                     "Invalid revision range %s..%s",
1433                                     arg, next);
1434                         }
1435
1436                         if (!cant_be_filename) {
1437                                 *dotdot = '.';
1438                                 verify_non_filename(revs->prefix, arg);
1439                         }
1440
1441                         if (symmetric) {
1442                                 exclude = get_merge_bases(a, b, 1);
1443                                 add_rev_cmdline_list(revs, exclude,
1444                                                      REV_CMD_MERGE_BASE,
1445                                                      flags_exclude);
1446                                 add_pending_commit_list(revs, exclude,
1447                                                         flags_exclude);
1448                                 free_commit_list(exclude);
1449                                 a_flags = flags | SYMMETRIC_LEFT;
1450                         } else
1451                                 a_flags = flags_exclude;
1452                         a->object.flags |= a_flags;
1453                         b->object.flags |= flags;
1454                         add_rev_cmdline(revs, &a->object, this,
1455                                         REV_CMD_LEFT, a_flags);
1456                         add_rev_cmdline(revs, &b->object, next,
1457                                         REV_CMD_RIGHT, flags);
1458                         add_pending_object(revs, &a->object, this);
1459                         add_pending_object(revs, &b->object, next);
1460                         return 0;
1461                 }
1462                 *dotdot = '.';
1463         }
1464         dotdot = strstr(arg, "^@");
1465         if (dotdot && !dotdot[2]) {
1466                 *dotdot = 0;
1467                 if (add_parents_only(revs, arg, flags))
1468                         return 0;
1469                 *dotdot = '^';
1470         }
1471         dotdot = strstr(arg, "^!");
1472         if (dotdot && !dotdot[2]) {
1473                 *dotdot = 0;
1474                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM)))
1475                         *dotdot = '^';
1476         }
1477
1478         local_flags = 0;
1479         if (*arg == '^') {
1480                 local_flags = UNINTERESTING | BOTTOM;
1481                 arg++;
1482         }
1483
1484         if (revarg_opt & REVARG_COMMITTISH)
1485                 get_sha1_flags = GET_SHA1_COMMITTISH;
1486
1487         if (get_sha1_with_context(arg, get_sha1_flags, sha1, &oc))
1488                 return revs->ignore_missing ? 0 : -1;
1489         if (!cant_be_filename)
1490                 verify_non_filename(revs->prefix, arg);
1491         object = get_reference(revs, arg, sha1, flags ^ local_flags);
1492         add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
1493         add_pending_object_with_mode(revs, object, arg, oc.mode);
1494         return 0;
1495 }
1496
1497 struct cmdline_pathspec {
1498         int alloc;
1499         int nr;
1500         const char **path;
1501 };
1502
1503 static void append_prune_data(struct cmdline_pathspec *prune, const char **av)
1504 {
1505         while (*av) {
1506                 ALLOC_GROW(prune->path, prune->nr+1, prune->alloc);
1507                 prune->path[prune->nr++] = *(av++);
1508         }
1509 }
1510
1511 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
1512                                      struct cmdline_pathspec *prune)
1513 {
1514         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
1515                 int len = sb->len;
1516                 if (len && sb->buf[len - 1] == '\n')
1517                         sb->buf[--len] = '\0';
1518                 ALLOC_GROW(prune->path, prune->nr+1, prune->alloc);
1519                 prune->path[prune->nr++] = xstrdup(sb->buf);
1520         }
1521 }
1522
1523 static void read_revisions_from_stdin(struct rev_info *revs,
1524                                       struct cmdline_pathspec *prune)
1525 {
1526         struct strbuf sb;
1527         int seen_dashdash = 0;
1528
1529         strbuf_init(&sb, 1000);
1530         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1531                 int len = sb.len;
1532                 if (len && sb.buf[len - 1] == '\n')
1533                         sb.buf[--len] = '\0';
1534                 if (!len)
1535                         break;
1536                 if (sb.buf[0] == '-') {
1537                         if (len == 2 && sb.buf[1] == '-') {
1538                                 seen_dashdash = 1;
1539                                 break;
1540                         }
1541                         die("options not supported in --stdin mode");
1542                 }
1543                 if (handle_revision_arg(sb.buf, revs, 0,
1544                                         REVARG_CANNOT_BE_FILENAME))
1545                         die("bad revision '%s'", sb.buf);
1546         }
1547         if (seen_dashdash)
1548                 read_pathspec_from_stdin(revs, &sb, prune);
1549         strbuf_release(&sb);
1550 }
1551
1552 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1553 {
1554         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1555 }
1556
1557 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1558 {
1559         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1560 }
1561
1562 static void add_message_grep(struct rev_info *revs, const char *pattern)
1563 {
1564         add_grep(revs, pattern, GREP_PATTERN_BODY);
1565 }
1566
1567 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1568                                int *unkc, const char **unkv)
1569 {
1570         const char *arg = argv[0];
1571         const char *optarg;
1572         int argcount;
1573
1574         /* pseudo revision arguments */
1575         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1576             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1577             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1578             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1579             !strcmp(arg, "--bisect") || !prefixcmp(arg, "--glob=") ||
1580             !prefixcmp(arg, "--branches=") || !prefixcmp(arg, "--tags=") ||
1581             !prefixcmp(arg, "--remotes=") || !prefixcmp(arg, "--no-walk="))
1582         {
1583                 unkv[(*unkc)++] = arg;
1584                 return 1;
1585         }
1586
1587         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1588                 revs->max_count = atoi(optarg);
1589                 revs->no_walk = 0;
1590                 return argcount;
1591         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1592                 revs->skip_count = atoi(optarg);
1593                 return argcount;
1594         } else if ((*arg == '-') && isdigit(arg[1])) {
1595         /* accept -<digit>, like traditional "head" */
1596                 revs->max_count = atoi(arg + 1);
1597                 revs->no_walk = 0;
1598         } else if (!strcmp(arg, "-n")) {
1599                 if (argc <= 1)
1600                         return error("-n requires an argument");
1601                 revs->max_count = atoi(argv[1]);
1602                 revs->no_walk = 0;
1603                 return 2;
1604         } else if (!prefixcmp(arg, "-n")) {
1605                 revs->max_count = atoi(arg + 2);
1606                 revs->no_walk = 0;
1607         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1608                 revs->max_age = atoi(optarg);
1609                 return argcount;
1610         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1611                 revs->max_age = approxidate(optarg);
1612                 return argcount;
1613         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1614                 revs->max_age = approxidate(optarg);
1615                 return argcount;
1616         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1617                 revs->min_age = atoi(optarg);
1618                 return argcount;
1619         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1620                 revs->min_age = approxidate(optarg);
1621                 return argcount;
1622         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1623                 revs->min_age = approxidate(optarg);
1624                 return argcount;
1625         } else if (!strcmp(arg, "--first-parent")) {
1626                 revs->first_parent_only = 1;
1627         } else if (!strcmp(arg, "--ancestry-path")) {
1628                 revs->ancestry_path = 1;
1629                 revs->simplify_history = 0;
1630                 revs->limited = 1;
1631         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1632                 init_reflog_walk(&revs->reflog_info);
1633         } else if (!strcmp(arg, "--default")) {
1634                 if (argc <= 1)
1635                         return error("bad --default argument");
1636                 revs->def = argv[1];
1637                 return 2;
1638         } else if (!strcmp(arg, "--merge")) {
1639                 revs->show_merge = 1;
1640         } else if (!strcmp(arg, "--topo-order")) {
1641                 revs->lifo = 1;
1642                 revs->topo_order = 1;
1643         } else if (!strcmp(arg, "--simplify-merges")) {
1644                 revs->simplify_merges = 1;
1645                 revs->topo_order = 1;
1646                 revs->rewrite_parents = 1;
1647                 revs->simplify_history = 0;
1648                 revs->limited = 1;
1649         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1650                 revs->simplify_merges = 1;
1651                 revs->topo_order = 1;
1652                 revs->rewrite_parents = 1;
1653                 revs->simplify_history = 0;
1654                 revs->simplify_by_decoration = 1;
1655                 revs->limited = 1;
1656                 revs->prune = 1;
1657                 load_ref_decorations(DECORATE_SHORT_REFS);
1658         } else if (!strcmp(arg, "--date-order")) {
1659                 revs->lifo = 0;
1660                 revs->topo_order = 1;
1661         } else if (!prefixcmp(arg, "--early-output")) {
1662                 int count = 100;
1663                 switch (arg[14]) {
1664                 case '=':
1665                         count = atoi(arg+15);
1666                         /* Fallthrough */
1667                 case 0:
1668                         revs->topo_order = 1;
1669                        revs->early_output = count;
1670                 }
1671         } else if (!strcmp(arg, "--parents")) {
1672                 revs->rewrite_parents = 1;
1673                 revs->print_parents = 1;
1674         } else if (!strcmp(arg, "--dense")) {
1675                 revs->dense = 1;
1676         } else if (!strcmp(arg, "--sparse")) {
1677                 revs->dense = 0;
1678         } else if (!strcmp(arg, "--show-all")) {
1679                 revs->show_all = 1;
1680         } else if (!strcmp(arg, "--remove-empty")) {
1681                 revs->remove_empty_trees = 1;
1682         } else if (!strcmp(arg, "--merges")) {
1683                 revs->min_parents = 2;
1684         } else if (!strcmp(arg, "--no-merges")) {
1685                 revs->max_parents = 1;
1686         } else if (!prefixcmp(arg, "--min-parents=")) {
1687                 revs->min_parents = atoi(arg+14);
1688         } else if (!prefixcmp(arg, "--no-min-parents")) {
1689                 revs->min_parents = 0;
1690         } else if (!prefixcmp(arg, "--max-parents=")) {
1691                 revs->max_parents = atoi(arg+14);
1692         } else if (!prefixcmp(arg, "--no-max-parents")) {
1693                 revs->max_parents = -1;
1694         } else if (!strcmp(arg, "--boundary")) {
1695                 revs->boundary = 1;
1696         } else if (!strcmp(arg, "--left-right")) {
1697                 revs->left_right = 1;
1698         } else if (!strcmp(arg, "--left-only")) {
1699                 if (revs->right_only)
1700                         die("--left-only is incompatible with --right-only"
1701                             " or --cherry");
1702                 revs->left_only = 1;
1703         } else if (!strcmp(arg, "--right-only")) {
1704                 if (revs->left_only)
1705                         die("--right-only is incompatible with --left-only");
1706                 revs->right_only = 1;
1707         } else if (!strcmp(arg, "--cherry")) {
1708                 if (revs->left_only)
1709                         die("--cherry is incompatible with --left-only");
1710                 revs->cherry_mark = 1;
1711                 revs->right_only = 1;
1712                 revs->max_parents = 1;
1713                 revs->limited = 1;
1714         } else if (!strcmp(arg, "--count")) {
1715                 revs->count = 1;
1716         } else if (!strcmp(arg, "--cherry-mark")) {
1717                 if (revs->cherry_pick)
1718                         die("--cherry-mark is incompatible with --cherry-pick");
1719                 revs->cherry_mark = 1;
1720                 revs->limited = 1; /* needs limit_list() */
1721         } else if (!strcmp(arg, "--cherry-pick")) {
1722                 if (revs->cherry_mark)
1723                         die("--cherry-pick is incompatible with --cherry-mark");
1724                 revs->cherry_pick = 1;
1725                 revs->limited = 1;
1726         } else if (!strcmp(arg, "--objects")) {
1727                 revs->tag_objects = 1;
1728                 revs->tree_objects = 1;
1729                 revs->blob_objects = 1;
1730         } else if (!strcmp(arg, "--objects-edge")) {
1731                 revs->tag_objects = 1;
1732                 revs->tree_objects = 1;
1733                 revs->blob_objects = 1;
1734                 revs->edge_hint = 1;
1735         } else if (!strcmp(arg, "--verify-objects")) {
1736                 revs->tag_objects = 1;
1737                 revs->tree_objects = 1;
1738                 revs->blob_objects = 1;
1739                 revs->verify_objects = 1;
1740         } else if (!strcmp(arg, "--unpacked")) {
1741                 revs->unpacked = 1;
1742         } else if (!prefixcmp(arg, "--unpacked=")) {
1743                 die("--unpacked=<packfile> no longer supported.");
1744         } else if (!strcmp(arg, "-r")) {
1745                 revs->diff = 1;
1746                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1747         } else if (!strcmp(arg, "-t")) {
1748                 revs->diff = 1;
1749                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1750                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1751         } else if (!strcmp(arg, "-m")) {
1752                 revs->ignore_merges = 0;
1753         } else if (!strcmp(arg, "-c")) {
1754                 revs->diff = 1;
1755                 revs->dense_combined_merges = 0;
1756                 revs->combine_merges = 1;
1757         } else if (!strcmp(arg, "--cc")) {
1758                 revs->diff = 1;
1759                 revs->dense_combined_merges = 1;
1760                 revs->combine_merges = 1;
1761         } else if (!strcmp(arg, "-v")) {
1762                 revs->verbose_header = 1;
1763         } else if (!strcmp(arg, "--pretty")) {
1764                 revs->verbose_header = 1;
1765                 revs->pretty_given = 1;
1766                 get_commit_format(arg+8, revs);
1767         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1768                 /*
1769                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1770                  * not allowed, since the argument is optional.
1771                  */
1772                 revs->verbose_header = 1;
1773                 revs->pretty_given = 1;
1774                 get_commit_format(arg+9, revs);
1775         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
1776                 revs->show_notes = 1;
1777                 revs->show_notes_given = 1;
1778                 revs->notes_opt.use_default_notes = 1;
1779         } else if (!strcmp(arg, "--show-signature")) {
1780                 revs->show_signature = 1;
1781         } else if (!prefixcmp(arg, "--show-notes=") ||
1782                    !prefixcmp(arg, "--notes=")) {
1783                 struct strbuf buf = STRBUF_INIT;
1784                 revs->show_notes = 1;
1785                 revs->show_notes_given = 1;
1786                 if (!prefixcmp(arg, "--show-notes")) {
1787                         if (revs->notes_opt.use_default_notes < 0)
1788                                 revs->notes_opt.use_default_notes = 1;
1789                         strbuf_addstr(&buf, arg+13);
1790                 }
1791                 else
1792                         strbuf_addstr(&buf, arg+8);
1793                 expand_notes_ref(&buf);
1794                 string_list_append(&revs->notes_opt.extra_notes_refs,
1795                                    strbuf_detach(&buf, NULL));
1796         } else if (!strcmp(arg, "--no-notes")) {
1797                 revs->show_notes = 0;
1798                 revs->show_notes_given = 1;
1799                 revs->notes_opt.use_default_notes = -1;
1800                 /* we have been strdup'ing ourselves, so trick
1801                  * string_list into free()ing strings */
1802                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
1803                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
1804                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
1805         } else if (!strcmp(arg, "--standard-notes")) {
1806                 revs->show_notes_given = 1;
1807                 revs->notes_opt.use_default_notes = 1;
1808         } else if (!strcmp(arg, "--no-standard-notes")) {
1809                 revs->notes_opt.use_default_notes = 0;
1810         } else if (!strcmp(arg, "--oneline")) {
1811                 revs->verbose_header = 1;
1812                 get_commit_format("oneline", revs);
1813                 revs->pretty_given = 1;
1814                 revs->abbrev_commit = 1;
1815         } else if (!strcmp(arg, "--graph")) {
1816                 revs->topo_order = 1;
1817                 revs->rewrite_parents = 1;
1818                 revs->graph = graph_init(revs);
1819         } else if (!strcmp(arg, "--root")) {
1820                 revs->show_root_diff = 1;
1821         } else if (!strcmp(arg, "--no-commit-id")) {
1822                 revs->no_commit_id = 1;
1823         } else if (!strcmp(arg, "--always")) {
1824                 revs->always_show_header = 1;
1825         } else if (!strcmp(arg, "--no-abbrev")) {
1826                 revs->abbrev = 0;
1827         } else if (!strcmp(arg, "--abbrev")) {
1828                 revs->abbrev = DEFAULT_ABBREV;
1829         } else if (!prefixcmp(arg, "--abbrev=")) {
1830                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1831                 if (revs->abbrev < MINIMUM_ABBREV)
1832                         revs->abbrev = MINIMUM_ABBREV;
1833                 else if (revs->abbrev > 40)
1834                         revs->abbrev = 40;
1835         } else if (!strcmp(arg, "--abbrev-commit")) {
1836                 revs->abbrev_commit = 1;
1837                 revs->abbrev_commit_given = 1;
1838         } else if (!strcmp(arg, "--no-abbrev-commit")) {
1839                 revs->abbrev_commit = 0;
1840         } else if (!strcmp(arg, "--full-diff")) {
1841                 revs->diff = 1;
1842                 revs->full_diff = 1;
1843         } else if (!strcmp(arg, "--full-history")) {
1844                 revs->simplify_history = 0;
1845         } else if (!strcmp(arg, "--relative-date")) {
1846                 revs->date_mode = DATE_RELATIVE;
1847                 revs->date_mode_explicit = 1;
1848         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
1849                 revs->date_mode = parse_date_format(optarg);
1850                 revs->date_mode_explicit = 1;
1851                 return argcount;
1852         } else if (!strcmp(arg, "--log-size")) {
1853                 revs->show_log_size = 1;
1854         }
1855         /*
1856          * Grepping the commit log
1857          */
1858         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
1859                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
1860                 return argcount;
1861         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
1862                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
1863                 return argcount;
1864         } else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
1865                 add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
1866                 return argcount;
1867         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
1868                 add_message_grep(revs, optarg);
1869                 return argcount;
1870         } else if (!strcmp(arg, "--grep-debug")) {
1871                 revs->grep_filter.debug = 1;
1872         } else if (!strcmp(arg, "--basic-regexp")) {
1873                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_BRE, &revs->grep_filter);
1874         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1875                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, &revs->grep_filter);
1876         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1877                 revs->grep_filter.regflags |= REG_ICASE;
1878                 DIFF_OPT_SET(&revs->diffopt, PICKAXE_IGNORE_CASE);
1879         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1880                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_FIXED, &revs->grep_filter);
1881         } else if (!strcmp(arg, "--perl-regexp")) {
1882                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_PCRE, &revs->grep_filter);
1883         } else if (!strcmp(arg, "--all-match")) {
1884                 revs->grep_filter.all_match = 1;
1885         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
1886                 if (strcmp(optarg, "none"))
1887                         git_log_output_encoding = xstrdup(optarg);
1888                 else
1889                         git_log_output_encoding = "";
1890                 return argcount;
1891         } else if (!strcmp(arg, "--reverse")) {
1892                 revs->reverse ^= 1;
1893         } else if (!strcmp(arg, "--children")) {
1894                 revs->children.name = "children";
1895                 revs->limited = 1;
1896         } else if (!strcmp(arg, "--ignore-missing")) {
1897                 revs->ignore_missing = 1;
1898         } else {
1899                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1900                 if (!opts)
1901                         unkv[(*unkc)++] = arg;
1902                 return opts;
1903         }
1904
1905         return 1;
1906 }
1907
1908 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1909                         const struct option *options,
1910                         const char * const usagestr[])
1911 {
1912         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1913                                     &ctx->cpidx, ctx->out);
1914         if (n <= 0) {
1915                 error("unknown option `%s'", ctx->argv[0]);
1916                 usage_with_options(usagestr, options);
1917         }
1918         ctx->argv += n;
1919         ctx->argc -= n;
1920 }
1921
1922 static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1923 {
1924         return for_each_ref_in_submodule(submodule, "refs/bisect/bad", fn, cb_data);
1925 }
1926
1927 static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1928 {
1929         return for_each_ref_in_submodule(submodule, "refs/bisect/good", fn, cb_data);
1930 }
1931
1932 static int handle_revision_pseudo_opt(const char *submodule,
1933                                 struct rev_info *revs,
1934                                 int argc, const char **argv, int *flags)
1935 {
1936         const char *arg = argv[0];
1937         const char *optarg;
1938         int argcount;
1939
1940         /*
1941          * NOTE!
1942          *
1943          * Commands like "git shortlog" will not accept the options below
1944          * unless parse_revision_opt queues them (as opposed to erroring
1945          * out).
1946          *
1947          * When implementing your new pseudo-option, remember to
1948          * register it in the list at the top of handle_revision_opt.
1949          */
1950         if (!strcmp(arg, "--all")) {
1951                 handle_refs(submodule, revs, *flags, for_each_ref_submodule);
1952                 handle_refs(submodule, revs, *flags, head_ref_submodule);
1953         } else if (!strcmp(arg, "--branches")) {
1954                 handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule);
1955         } else if (!strcmp(arg, "--bisect")) {
1956                 handle_refs(submodule, revs, *flags, for_each_bad_bisect_ref);
1957                 handle_refs(submodule, revs, *flags ^ (UNINTERESTING | BOTTOM), for_each_good_bisect_ref);
1958                 revs->bisect = 1;
1959         } else if (!strcmp(arg, "--tags")) {
1960                 handle_refs(submodule, revs, *flags, for_each_tag_ref_submodule);
1961         } else if (!strcmp(arg, "--remotes")) {
1962                 handle_refs(submodule, revs, *flags, for_each_remote_ref_submodule);
1963         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
1964                 struct all_refs_cb cb;
1965                 init_all_refs_cb(&cb, revs, *flags);
1966                 for_each_glob_ref(handle_one_ref, optarg, &cb);
1967                 return argcount;
1968         } else if (!prefixcmp(arg, "--branches=")) {
1969                 struct all_refs_cb cb;
1970                 init_all_refs_cb(&cb, revs, *flags);
1971                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
1972         } else if (!prefixcmp(arg, "--tags=")) {
1973                 struct all_refs_cb cb;
1974                 init_all_refs_cb(&cb, revs, *flags);
1975                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
1976         } else if (!prefixcmp(arg, "--remotes=")) {
1977                 struct all_refs_cb cb;
1978                 init_all_refs_cb(&cb, revs, *flags);
1979                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
1980         } else if (!strcmp(arg, "--reflog")) {
1981                 handle_reflog(revs, *flags);
1982         } else if (!strcmp(arg, "--not")) {
1983                 *flags ^= UNINTERESTING | BOTTOM;
1984         } else if (!strcmp(arg, "--no-walk")) {
1985                 revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
1986         } else if (!prefixcmp(arg, "--no-walk=")) {
1987                 /*
1988                  * Detached form ("--no-walk X" as opposed to "--no-walk=X")
1989                  * not allowed, since the argument is optional.
1990                  */
1991                 if (!strcmp(arg + 10, "sorted"))
1992                         revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
1993                 else if (!strcmp(arg + 10, "unsorted"))
1994                         revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
1995                 else
1996                         return error("invalid argument to --no-walk");
1997         } else if (!strcmp(arg, "--do-walk")) {
1998                 revs->no_walk = 0;
1999         } else {
2000                 return 0;
2001         }
2002
2003         return 1;
2004 }
2005
2006 /*
2007  * Parse revision information, filling in the "rev_info" structure,
2008  * and removing the used arguments from the argument list.
2009  *
2010  * Returns the number of arguments left that weren't recognized
2011  * (which are also moved to the head of the argument list)
2012  */
2013 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
2014 {
2015         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0, revarg_opt;
2016         struct cmdline_pathspec prune_data;
2017         const char *submodule = NULL;
2018
2019         memset(&prune_data, 0, sizeof(prune_data));
2020         if (opt)
2021                 submodule = opt->submodule;
2022
2023         /* First, search for "--" */
2024         if (opt && opt->assume_dashdash) {
2025                 seen_dashdash = 1;
2026         } else {
2027                 seen_dashdash = 0;
2028                 for (i = 1; i < argc; i++) {
2029                         const char *arg = argv[i];
2030                         if (strcmp(arg, "--"))
2031                                 continue;
2032                         argv[i] = NULL;
2033                         argc = i;
2034                         if (argv[i + 1])
2035                                 append_prune_data(&prune_data, argv + i + 1);
2036                         seen_dashdash = 1;
2037                         break;
2038                 }
2039         }
2040
2041         /* Second, deal with arguments and options */
2042         flags = 0;
2043         revarg_opt = opt ? opt->revarg_opt : 0;
2044         if (seen_dashdash)
2045                 revarg_opt |= REVARG_CANNOT_BE_FILENAME;
2046         read_from_stdin = 0;
2047         for (left = i = 1; i < argc; i++) {
2048                 const char *arg = argv[i];
2049                 if (*arg == '-') {
2050                         int opts;
2051
2052                         opts = handle_revision_pseudo_opt(submodule,
2053                                                 revs, argc - i, argv + i,
2054                                                 &flags);
2055                         if (opts > 0) {
2056                                 i += opts - 1;
2057                                 continue;
2058                         }
2059
2060                         if (!strcmp(arg, "--stdin")) {
2061                                 if (revs->disable_stdin) {
2062                                         argv[left++] = arg;
2063                                         continue;
2064                                 }
2065                                 if (read_from_stdin++)
2066                                         die("--stdin given twice?");
2067                                 read_revisions_from_stdin(revs, &prune_data);
2068                                 continue;
2069                         }
2070
2071                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
2072                         if (opts > 0) {
2073                                 i += opts - 1;
2074                                 continue;
2075                         }
2076                         if (opts < 0)
2077                                 exit(128);
2078                         continue;
2079                 }
2080
2081
2082                 if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
2083                         int j;
2084                         if (seen_dashdash || *arg == '^')
2085                                 die("bad revision '%s'", arg);
2086
2087                         /* If we didn't have a "--":
2088                          * (1) all filenames must exist;
2089                          * (2) all rev-args must not be interpretable
2090                          *     as a valid filename.
2091                          * but the latter we have checked in the main loop.
2092                          */
2093                         for (j = i; j < argc; j++)
2094                                 verify_filename(revs->prefix, argv[j], j == i);
2095
2096                         append_prune_data(&prune_data, argv + i);
2097                         break;
2098                 }
2099                 else
2100                         got_rev_arg = 1;
2101         }
2102
2103         if (prune_data.nr) {
2104                 /*
2105                  * If we need to introduce the magic "a lone ':' means no
2106                  * pathspec whatsoever", here is the place to do so.
2107                  *
2108                  * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
2109                  *      prune_data.nr = 0;
2110                  *      prune_data.alloc = 0;
2111                  *      free(prune_data.path);
2112                  *      prune_data.path = NULL;
2113                  * } else {
2114                  *      terminate prune_data.alloc with NULL and
2115                  *      call init_pathspec() to set revs->prune_data here.
2116                  * }
2117                  */
2118                 ALLOC_GROW(prune_data.path, prune_data.nr+1, prune_data.alloc);
2119                 prune_data.path[prune_data.nr++] = NULL;
2120                 init_pathspec(&revs->prune_data,
2121                               get_pathspec(revs->prefix, prune_data.path));
2122         }
2123
2124         if (revs->def == NULL)
2125                 revs->def = opt ? opt->def : NULL;
2126         if (opt && opt->tweak)
2127                 opt->tweak(revs, opt);
2128         if (revs->show_merge)
2129                 prepare_show_merge(revs);
2130         if (revs->def && !revs->pending.nr && !got_rev_arg) {
2131                 unsigned char sha1[20];
2132                 struct object *object;
2133                 struct object_context oc;
2134                 if (get_sha1_with_context(revs->def, 0, sha1, &oc))
2135                         die("bad default revision '%s'", revs->def);
2136                 object = get_reference(revs, revs->def, sha1, 0);
2137                 add_pending_object_with_mode(revs, object, revs->def, oc.mode);
2138         }
2139
2140         /* Did the user ask for any diff output? Run the diff! */
2141         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
2142                 revs->diff = 1;
2143
2144         /* Pickaxe, diff-filter and rename following need diffs */
2145         if (revs->diffopt.pickaxe ||
2146             revs->diffopt.filter ||
2147             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
2148                 revs->diff = 1;
2149
2150         if (revs->topo_order)
2151                 revs->limited = 1;
2152
2153         if (revs->prune_data.nr) {
2154                 diff_tree_setup_paths(revs->prune_data.raw, &revs->pruning);
2155                 /* Can't prune commits with rename following: the paths change.. */
2156                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
2157                         revs->prune = 1;
2158                 if (!revs->full_diff)
2159                         diff_tree_setup_paths(revs->prune_data.raw, &revs->diffopt);
2160         }
2161         if (revs->combine_merges)
2162                 revs->ignore_merges = 0;
2163         revs->diffopt.abbrev = revs->abbrev;
2164
2165         if (revs->line_level_traverse) {
2166                 revs->limited = 1;
2167                 revs->topo_order = 1;
2168         }
2169
2170         diff_setup_done(&revs->diffopt);
2171
2172         grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
2173                                  &revs->grep_filter);
2174         compile_grep_patterns(&revs->grep_filter);
2175
2176         if (revs->reverse && revs->reflog_info)
2177                 die("cannot combine --reverse with --walk-reflogs");
2178         if (revs->rewrite_parents && revs->children.name)
2179                 die("cannot combine --parents and --children");
2180
2181         /*
2182          * Limitations on the graph functionality
2183          */
2184         if (revs->reverse && revs->graph)
2185                 die("cannot combine --reverse with --graph");
2186
2187         if (revs->reflog_info && revs->graph)
2188                 die("cannot combine --walk-reflogs with --graph");
2189         if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
2190                 die("cannot use --grep-reflog without --walk-reflogs");
2191
2192         return left;
2193 }
2194
2195 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
2196 {
2197         struct commit_list *l = xcalloc(1, sizeof(*l));
2198
2199         l->item = child;
2200         l->next = add_decoration(&revs->children, &parent->object, l);
2201 }
2202
2203 static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
2204 {
2205         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2206         struct commit_list **pp, *p;
2207         int surviving_parents;
2208
2209         /* Examine existing parents while marking ones we have seen... */
2210         pp = &commit->parents;
2211         surviving_parents = 0;
2212         while ((p = *pp) != NULL) {
2213                 struct commit *parent = p->item;
2214                 if (parent->object.flags & TMP_MARK) {
2215                         *pp = p->next;
2216                         if (ts)
2217                                 compact_treesame(revs, commit, surviving_parents);
2218                         continue;
2219                 }
2220                 parent->object.flags |= TMP_MARK;
2221                 surviving_parents++;
2222                 pp = &p->next;
2223         }
2224         /* clear the temporary mark */
2225         for (p = commit->parents; p; p = p->next) {
2226                 p->item->object.flags &= ~TMP_MARK;
2227         }
2228         /* no update_treesame() - removing duplicates can't affect TREESAME */
2229         return surviving_parents;
2230 }
2231
2232 struct merge_simplify_state {
2233         struct commit *simplified;
2234 };
2235
2236 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
2237 {
2238         struct merge_simplify_state *st;
2239
2240         st = lookup_decoration(&revs->merge_simplification, &commit->object);
2241         if (!st) {
2242                 st = xcalloc(1, sizeof(*st));
2243                 add_decoration(&revs->merge_simplification, &commit->object, st);
2244         }
2245         return st;
2246 }
2247
2248 static int mark_redundant_parents(struct rev_info *revs, struct commit *commit)
2249 {
2250         struct commit_list *h = reduce_heads(commit->parents);
2251         int i = 0, marked = 0;
2252         struct commit_list *po, *pn;
2253
2254         /* Want these for sanity-checking only */
2255         int orig_cnt = commit_list_count(commit->parents);
2256         int cnt = commit_list_count(h);
2257
2258         /*
2259          * Not ready to remove items yet, just mark them for now, based
2260          * on the output of reduce_heads(). reduce_heads outputs the reduced
2261          * set in its original order, so this isn't too hard.
2262          */
2263         po = commit->parents;
2264         pn = h;
2265         while (po) {
2266                 if (pn && po->item == pn->item) {
2267                         pn = pn->next;
2268                         i++;
2269                 } else {
2270                         po->item->object.flags |= TMP_MARK;
2271                         marked++;
2272                 }
2273                 po=po->next;
2274         }
2275
2276         if (i != cnt || cnt+marked != orig_cnt)
2277                 die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
2278
2279         free_commit_list(h);
2280
2281         return marked;
2282 }
2283
2284 static int mark_treesame_root_parents(struct rev_info *revs, struct commit *commit)
2285 {
2286         struct commit_list *p;
2287         int marked = 0;
2288
2289         for (p = commit->parents; p; p = p->next) {
2290                 struct commit *parent = p->item;
2291                 if (!parent->parents && (parent->object.flags & TREESAME)) {
2292                         parent->object.flags |= TMP_MARK;
2293                         marked++;
2294                 }
2295         }
2296
2297         return marked;
2298 }
2299
2300 /*
2301  * Awkward naming - this means one parent we are TREESAME to.
2302  * cf mark_treesame_root_parents: root parents that are TREESAME (to an
2303  * empty tree). Better name suggestions?
2304  */
2305 static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
2306 {
2307         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2308         struct commit *unmarked = NULL, *marked = NULL;
2309         struct commit_list *p;
2310         unsigned n;
2311
2312         for (p = commit->parents, n = 0; p; p = p->next, n++) {
2313                 if (ts->treesame[n]) {
2314                         if (p->item->object.flags & TMP_MARK) {
2315                                 if (!marked)
2316                                         marked = p->item;
2317                         } else {
2318                                 if (!unmarked) {
2319                                         unmarked = p->item;
2320                                         break;
2321                                 }
2322                         }
2323                 }
2324         }
2325
2326         /*
2327          * If we are TREESAME to a marked-for-deletion parent, but not to any
2328          * unmarked parents, unmark the first TREESAME parent. This is the
2329          * parent that the default simplify_history==1 scan would have followed,
2330          * and it doesn't make sense to omit that path when asking for a
2331          * simplified full history. Retaining it improves the chances of
2332          * understanding odd missed merges that took an old version of a file.
2333          *
2334          * Example:
2335          *
2336          *   I--------*X       A modified the file, but mainline merge X used
2337          *    \       /        "-s ours", so took the version from I. X is
2338          *     `-*A--'         TREESAME to I and !TREESAME to A.
2339          *
2340          * Default log from X would produce "I". Without this check,
2341          * --full-history --simplify-merges would produce "I-A-X", showing
2342          * the merge commit X and that it changed A, but not making clear that
2343          * it had just taken the I version. With this check, the topology above
2344          * is retained.
2345          *
2346          * Note that it is possible that the simplification chooses a different
2347          * TREESAME parent from the default, in which case this test doesn't
2348          * activate, and we _do_ drop the default parent. Example:
2349          *
2350          *   I------X         A modified the file, but it was reverted in B,
2351          *    \    /          meaning mainline merge X is TREESAME to both
2352          *    *A-*B           parents.
2353          *
2354          * Default log would produce "I" by following the first parent;
2355          * --full-history --simplify-merges will produce "I-A-B". But this is a
2356          * reasonable result - it presents a logical full history leading from
2357          * I to X, and X is not an important merge.
2358          */
2359         if (!unmarked && marked) {
2360                 marked->object.flags &= ~TMP_MARK;
2361                 return 1;
2362         }
2363
2364         return 0;
2365 }
2366
2367 static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
2368 {
2369         struct commit_list **pp, *p;
2370         int nth_parent, removed = 0;
2371
2372         pp = &commit->parents;
2373         nth_parent = 0;
2374         while ((p = *pp) != NULL) {
2375                 struct commit *parent = p->item;
2376                 if (parent->object.flags & TMP_MARK) {
2377                         parent->object.flags &= ~TMP_MARK;
2378                         *pp = p->next;
2379                         free(p);
2380                         removed++;
2381                         compact_treesame(revs, commit, nth_parent);
2382                         continue;
2383                 }
2384                 pp = &p->next;
2385                 nth_parent++;
2386         }
2387
2388         /* Removing parents can only increase TREESAMEness */
2389         if (removed && !(commit->object.flags & TREESAME))
2390                 update_treesame(revs, commit);
2391
2392         return nth_parent;
2393 }
2394
2395 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
2396 {
2397         struct commit_list *p;
2398         struct commit *parent;
2399         struct merge_simplify_state *st, *pst;
2400         int cnt;
2401
2402         st = locate_simplify_state(revs, commit);
2403
2404         /*
2405          * Have we handled this one?
2406          */
2407         if (st->simplified)
2408                 return tail;
2409
2410         /*
2411          * An UNINTERESTING commit simplifies to itself, so does a
2412          * root commit.  We do not rewrite parents of such commit
2413          * anyway.
2414          */
2415         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
2416                 st->simplified = commit;
2417                 return tail;
2418         }
2419
2420         /*
2421          * Do we know what commit all of our parents that matter
2422          * should be rewritten to?  Otherwise we are not ready to
2423          * rewrite this one yet.
2424          */
2425         for (cnt = 0, p = commit->parents; p; p = p->next) {
2426                 pst = locate_simplify_state(revs, p->item);
2427                 if (!pst->simplified) {
2428                         tail = &commit_list_insert(p->item, tail)->next;
2429                         cnt++;
2430                 }
2431                 if (revs->first_parent_only)
2432                         break;
2433         }
2434         if (cnt) {
2435                 tail = &commit_list_insert(commit, tail)->next;
2436                 return tail;
2437         }
2438
2439         /*
2440          * Rewrite our list of parents. Note that this cannot
2441          * affect our TREESAME flags in any way - a commit is
2442          * always TREESAME to its simplification.
2443          */
2444         for (p = commit->parents; p; p = p->next) {
2445                 pst = locate_simplify_state(revs, p->item);
2446                 p->item = pst->simplified;
2447                 if (revs->first_parent_only)
2448                         break;
2449         }
2450
2451         if (revs->first_parent_only)
2452                 cnt = 1;
2453         else
2454                 cnt = remove_duplicate_parents(revs, commit);
2455
2456         /*
2457          * It is possible that we are a merge and one side branch
2458          * does not have any commit that touches the given paths;
2459          * in such a case, the immediate parent from that branch
2460          * will be rewritten to be the merge base.
2461          *
2462          *      o----X          X: the commit we are looking at;
2463          *     /    /           o: a commit that touches the paths;
2464          * ---o----'
2465          *
2466          * Further, a merge of an independent branch that doesn't
2467          * touch the path will reduce to a treesame root parent:
2468          *
2469          *  ----o----X          X: the commit we are looking at;
2470          *          /           o: a commit that touches the paths;
2471          *         r            r: a root commit not touching the paths
2472          *
2473          * Detect and simplify both cases.
2474          */
2475         if (1 < cnt) {
2476                 int marked = mark_redundant_parents(revs, commit);
2477                 marked += mark_treesame_root_parents(revs, commit);
2478                 if (marked)
2479                         marked -= leave_one_treesame_to_parent(revs, commit);
2480                 if (marked)
2481                         cnt = remove_marked_parents(revs, commit);
2482         }
2483
2484         /*
2485          * A commit simplifies to itself if it is a root, if it is
2486          * UNINTERESTING, if it touches the given paths, or if it is a
2487          * merge and its parents don't simplify to one relevant commit
2488          * (the first two cases are already handled at the beginning of
2489          * this function).
2490          *
2491          * Otherwise, it simplifies to what its sole relevant parent
2492          * simplifies to.
2493          */
2494         if (!cnt ||
2495             (commit->object.flags & UNINTERESTING) ||
2496             !(commit->object.flags & TREESAME) ||
2497             (parent = one_relevant_parent(revs, commit->parents)) == NULL)
2498                 st->simplified = commit;
2499         else {
2500                 pst = locate_simplify_state(revs, parent);
2501                 st->simplified = pst->simplified;
2502         }
2503         return tail;
2504 }
2505
2506 static void simplify_merges(struct rev_info *revs)
2507 {
2508         struct commit_list *list, *next;
2509         struct commit_list *yet_to_do, **tail;
2510         struct commit *commit;
2511
2512         if (!revs->prune)
2513                 return;
2514
2515         /* feed the list reversed */
2516         yet_to_do = NULL;
2517         for (list = revs->commits; list; list = next) {
2518                 commit = list->item;
2519                 next = list->next;
2520                 /*
2521                  * Do not free(list) here yet; the original list
2522                  * is used later in this function.
2523                  */
2524                 commit_list_insert(commit, &yet_to_do);
2525         }
2526         while (yet_to_do) {
2527                 list = yet_to_do;
2528                 yet_to_do = NULL;
2529                 tail = &yet_to_do;
2530                 while (list) {
2531                         commit = list->item;
2532                         next = list->next;
2533                         free(list);
2534                         list = next;
2535                         tail = simplify_one(revs, commit, tail);
2536                 }
2537         }
2538
2539         /* clean up the result, removing the simplified ones */
2540         list = revs->commits;
2541         revs->commits = NULL;
2542         tail = &revs->commits;
2543         while (list) {
2544                 struct merge_simplify_state *st;
2545
2546                 commit = list->item;
2547                 next = list->next;
2548                 free(list);
2549                 list = next;
2550                 st = locate_simplify_state(revs, commit);
2551                 if (st->simplified == commit)
2552                         tail = &commit_list_insert(commit, tail)->next;
2553         }
2554 }
2555
2556 static void set_children(struct rev_info *revs)
2557 {
2558         struct commit_list *l;
2559         for (l = revs->commits; l; l = l->next) {
2560                 struct commit *commit = l->item;
2561                 struct commit_list *p;
2562
2563                 for (p = commit->parents; p; p = p->next)
2564                         add_child(revs, p->item, commit);
2565         }
2566 }
2567
2568 void reset_revision_walk(void)
2569 {
2570         clear_object_flags(SEEN | ADDED | SHOWN);
2571 }
2572
2573 int prepare_revision_walk(struct rev_info *revs)
2574 {
2575         int nr = revs->pending.nr;
2576         struct object_array_entry *e, *list;
2577         struct commit_list **next = &revs->commits;
2578
2579         e = list = revs->pending.objects;
2580         revs->pending.nr = 0;
2581         revs->pending.alloc = 0;
2582         revs->pending.objects = NULL;
2583         while (--nr >= 0) {
2584                 struct commit *commit = handle_commit(revs, e->item, e->name);
2585                 if (commit) {
2586                         if (!(commit->object.flags & SEEN)) {
2587                                 commit->object.flags |= SEEN;
2588                                 next = commit_list_append(commit, next);
2589                         }
2590                 }
2591                 e++;
2592         }
2593         if (!revs->leak_pending)
2594                 free(list);
2595
2596         /* Signal whether we need per-parent treesame decoration */
2597         if (revs->simplify_merges ||
2598             (revs->limited && limiting_can_increase_treesame(revs)))
2599                 revs->treesame.name = "treesame";
2600
2601         if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
2602                 commit_list_sort_by_date(&revs->commits);
2603         if (revs->no_walk)
2604                 return 0;
2605         if (revs->limited)
2606                 if (limit_list(revs) < 0)
2607                         return -1;
2608         if (revs->topo_order)
2609                 sort_in_topological_order(&revs->commits, revs->lifo);
2610         if (revs->line_level_traverse)
2611                 line_log_filter(revs);
2612         if (revs->simplify_merges)
2613                 simplify_merges(revs);
2614         if (revs->children.name)
2615                 set_children(revs);
2616         return 0;
2617 }
2618
2619 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
2620 {
2621         struct commit_list *cache = NULL;
2622
2623         for (;;) {
2624                 struct commit *p = *pp;
2625                 if (!revs->limited)
2626                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
2627                                 return rewrite_one_error;
2628                 if (p->object.flags & UNINTERESTING)
2629                         return rewrite_one_ok;
2630                 if (!(p->object.flags & TREESAME))
2631                         return rewrite_one_ok;
2632                 if (!p->parents)
2633                         return rewrite_one_noparents;
2634                 if ((p = one_relevant_parent(revs, p->parents)) == NULL)
2635                         return rewrite_one_ok;
2636                 *pp = p;
2637         }
2638 }
2639
2640 int rewrite_parents(struct rev_info *revs, struct commit *commit,
2641         rewrite_parent_fn_t rewrite_parent)
2642 {
2643         struct commit_list **pp = &commit->parents;
2644         while (*pp) {
2645                 struct commit_list *parent = *pp;
2646                 switch (rewrite_parent(revs, &parent->item)) {
2647                 case rewrite_one_ok:
2648                         break;
2649                 case rewrite_one_noparents:
2650                         *pp = parent->next;
2651                         continue;
2652                 case rewrite_one_error:
2653                         return -1;
2654                 }
2655                 pp = &parent->next;
2656         }
2657         remove_duplicate_parents(revs, commit);
2658         return 0;
2659 }
2660
2661 static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
2662 {
2663         char *person, *endp;
2664         size_t len, namelen, maillen;
2665         const char *name;
2666         const char *mail;
2667         struct ident_split ident;
2668
2669         person = strstr(buf->buf, what);
2670         if (!person)
2671                 return 0;
2672
2673         person += strlen(what);
2674         endp = strchr(person, '\n');
2675         if (!endp)
2676                 return 0;
2677
2678         len = endp - person;
2679
2680         if (split_ident_line(&ident, person, len))
2681                 return 0;
2682
2683         mail = ident.mail_begin;
2684         maillen = ident.mail_end - ident.mail_begin;
2685         name = ident.name_begin;
2686         namelen = ident.name_end - ident.name_begin;
2687
2688         if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
2689                 struct strbuf namemail = STRBUF_INIT;
2690
2691                 strbuf_addf(&namemail, "%.*s <%.*s>",
2692                             (int)namelen, name, (int)maillen, mail);
2693
2694                 strbuf_splice(buf, ident.name_begin - buf->buf,
2695                               ident.mail_end - ident.name_begin + 1,
2696                               namemail.buf, namemail.len);
2697
2698                 strbuf_release(&namemail);
2699
2700                 return 1;
2701         }
2702
2703         return 0;
2704 }
2705
2706 static int commit_match(struct commit *commit, struct rev_info *opt)
2707 {
2708         int retval;
2709         const char *encoding;
2710         char *message;
2711         struct strbuf buf = STRBUF_INIT;
2712
2713         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
2714                 return 1;
2715
2716         /* Prepend "fake" headers as needed */
2717         if (opt->grep_filter.use_reflog_filter) {
2718                 strbuf_addstr(&buf, "reflog ");
2719                 get_reflog_message(&buf, opt->reflog_info);
2720                 strbuf_addch(&buf, '\n');
2721         }
2722
2723         /*
2724          * We grep in the user's output encoding, under the assumption that it
2725          * is the encoding they are most likely to write their grep pattern
2726          * for. In addition, it means we will match the "notes" encoding below,
2727          * so we will not end up with a buffer that has two different encodings
2728          * in it.
2729          */
2730         encoding = get_log_output_encoding();
2731         message = logmsg_reencode(commit, NULL, encoding);
2732
2733         /* Copy the commit to temporary if we are using "fake" headers */
2734         if (buf.len)
2735                 strbuf_addstr(&buf, message);
2736
2737         if (opt->grep_filter.header_list && opt->mailmap) {
2738                 if (!buf.len)
2739                         strbuf_addstr(&buf, message);
2740
2741                 commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
2742                 commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
2743         }
2744
2745         /* Append "fake" message parts as needed */
2746         if (opt->show_notes) {
2747                 if (!buf.len)
2748                         strbuf_addstr(&buf, message);
2749                 format_display_notes(commit->object.sha1, &buf, encoding, 1);
2750         }
2751
2752         /* Find either in the original commit message, or in the temporary */
2753         if (buf.len)
2754                 retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
2755         else
2756                 retval = grep_buffer(&opt->grep_filter,
2757                                      message, strlen(message));
2758         strbuf_release(&buf);
2759         logmsg_free(message, commit);
2760         return retval;
2761 }
2762
2763 static inline int want_ancestry(struct rev_info *revs)
2764 {
2765         return (revs->rewrite_parents || revs->children.name);
2766 }
2767
2768 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
2769 {
2770         if (commit->object.flags & SHOWN)
2771                 return commit_ignore;
2772         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
2773                 return commit_ignore;
2774         if (revs->show_all)
2775                 return commit_show;
2776         if (commit->object.flags & UNINTERESTING)
2777                 return commit_ignore;
2778         if (revs->min_age != -1 && (commit->date > revs->min_age))
2779                 return commit_ignore;
2780         if (revs->min_parents || (revs->max_parents >= 0)) {
2781                 int n = commit_list_count(commit->parents);
2782                 if ((n < revs->min_parents) ||
2783                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
2784                         return commit_ignore;
2785         }
2786         if (!commit_match(commit, revs))
2787                 return commit_ignore;
2788         if (revs->prune && revs->dense) {
2789                 /* Commit without changes? */
2790                 if (commit->object.flags & TREESAME) {
2791                         int n;
2792                         struct commit_list *p;
2793                         /* drop merges unless we want parenthood */
2794                         if (!want_ancestry(revs))
2795                                 return commit_ignore;
2796                         /*
2797                          * If we want ancestry, then need to keep any merges
2798                          * between relevant commits to tie together topology.
2799                          * For consistency with TREESAME and simplification
2800                          * use "relevant" here rather than just INTERESTING,
2801                          * to treat bottom commit(s) as part of the topology.
2802                          */
2803                         for (n = 0, p = commit->parents; p; p = p->next)
2804                                 if (relevant_commit(p->item))
2805                                         if (++n >= 2)
2806                                                 return commit_show;
2807                         return commit_ignore;
2808                 }
2809         }
2810         return commit_show;
2811 }
2812
2813 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
2814 {
2815         enum commit_action action = get_commit_action(revs, commit);
2816
2817         if (action == commit_show &&
2818             !revs->show_all &&
2819             revs->prune && revs->dense && want_ancestry(revs)) {
2820                 if (rewrite_parents(revs, commit, rewrite_one) < 0)
2821                         return commit_error;
2822         }
2823         return action;
2824 }
2825
2826 static struct commit *get_revision_1(struct rev_info *revs)
2827 {
2828         if (!revs->commits)
2829                 return NULL;
2830
2831         do {
2832                 struct commit_list *entry = revs->commits;
2833                 struct commit *commit = entry->item;
2834
2835                 revs->commits = entry->next;
2836                 free(entry);
2837
2838                 if (revs->reflog_info) {
2839                         fake_reflog_parent(revs->reflog_info, commit);
2840                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
2841                 }
2842
2843                 /*
2844                  * If we haven't done the list limiting, we need to look at
2845                  * the parents here. We also need to do the date-based limiting
2846                  * that we'd otherwise have done in limit_list().
2847                  */
2848                 if (!revs->limited) {
2849                         if (revs->max_age != -1 &&
2850                             (commit->date < revs->max_age))
2851                                 continue;
2852                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
2853                                 die("Failed to traverse parents of commit %s",
2854                                     sha1_to_hex(commit->object.sha1));
2855                 }
2856
2857                 switch (simplify_commit(revs, commit)) {
2858                 case commit_ignore:
2859                         continue;
2860                 case commit_error:
2861                         die("Failed to simplify parents of commit %s",
2862                             sha1_to_hex(commit->object.sha1));
2863                 default:
2864                         return commit;
2865                 }
2866         } while (revs->commits);
2867         return NULL;
2868 }
2869
2870 /*
2871  * Return true for entries that have not yet been shown.  (This is an
2872  * object_array_each_func_t.)
2873  */
2874 static int entry_unshown(struct object_array_entry *entry, void *cb_data_unused)
2875 {
2876         return !(entry->item->flags & SHOWN);
2877 }
2878
2879 /*
2880  * If array is on the verge of a realloc, garbage-collect any entries
2881  * that have already been shown to try to free up some space.
2882  */
2883 static void gc_boundary(struct object_array *array)
2884 {
2885         if (array->nr == array->alloc)
2886                 object_array_filter(array, entry_unshown, NULL);
2887 }
2888
2889 static void create_boundary_commit_list(struct rev_info *revs)
2890 {
2891         unsigned i;
2892         struct commit *c;
2893         struct object_array *array = &revs->boundary_commits;
2894         struct object_array_entry *objects = array->objects;
2895
2896         /*
2897          * If revs->commits is non-NULL at this point, an error occurred in
2898          * get_revision_1().  Ignore the error and continue printing the
2899          * boundary commits anyway.  (This is what the code has always
2900          * done.)
2901          */
2902         if (revs->commits) {
2903                 free_commit_list(revs->commits);
2904                 revs->commits = NULL;
2905         }
2906
2907         /*
2908          * Put all of the actual boundary commits from revs->boundary_commits
2909          * into revs->commits
2910          */
2911         for (i = 0; i < array->nr; i++) {
2912                 c = (struct commit *)(objects[i].item);
2913                 if (!c)
2914                         continue;
2915                 if (!(c->object.flags & CHILD_SHOWN))
2916                         continue;
2917                 if (c->object.flags & (SHOWN | BOUNDARY))
2918                         continue;
2919                 c->object.flags |= BOUNDARY;
2920                 commit_list_insert(c, &revs->commits);
2921         }
2922
2923         /*
2924          * If revs->topo_order is set, sort the boundary commits
2925          * in topological order
2926          */
2927         sort_in_topological_order(&revs->commits, revs->lifo);
2928 }
2929
2930 static struct commit *get_revision_internal(struct rev_info *revs)
2931 {
2932         struct commit *c = NULL;
2933         struct commit_list *l;
2934
2935         if (revs->boundary == 2) {
2936                 /*
2937                  * All of the normal commits have already been returned,
2938                  * and we are now returning boundary commits.
2939                  * create_boundary_commit_list() has populated
2940                  * revs->commits with the remaining commits to return.
2941                  */
2942                 c = pop_commit(&revs->commits);
2943                 if (c)
2944                         c->object.flags |= SHOWN;
2945                 return c;
2946         }
2947
2948         /*
2949          * If our max_count counter has reached zero, then we are done. We
2950          * don't simply return NULL because we still might need to show
2951          * boundary commits. But we want to avoid calling get_revision_1, which
2952          * might do a considerable amount of work finding the next commit only
2953          * for us to throw it away.
2954          *
2955          * If it is non-zero, then either we don't have a max_count at all
2956          * (-1), or it is still counting, in which case we decrement.
2957          */
2958         if (revs->max_count) {
2959                 c = get_revision_1(revs);
2960                 if (c) {
2961                         while (0 < revs->skip_count) {
2962                                 revs->skip_count--;
2963                                 c = get_revision_1(revs);
2964                                 if (!c)
2965                                         break;
2966                         }
2967                 }
2968
2969                 if (revs->max_count > 0)
2970                         revs->max_count--;
2971         }
2972
2973         if (c)
2974                 c->object.flags |= SHOWN;
2975
2976         if (!revs->boundary) {
2977                 return c;
2978         }
2979
2980         if (!c) {
2981                 /*
2982                  * get_revision_1() runs out the commits, and
2983                  * we are done computing the boundaries.
2984                  * switch to boundary commits output mode.
2985                  */
2986                 revs->boundary = 2;
2987
2988                 /*
2989                  * Update revs->commits to contain the list of
2990                  * boundary commits.
2991                  */
2992                 create_boundary_commit_list(revs);
2993
2994                 return get_revision_internal(revs);
2995         }
2996
2997         /*
2998          * boundary commits are the commits that are parents of the
2999          * ones we got from get_revision_1() but they themselves are
3000          * not returned from get_revision_1().  Before returning
3001          * 'c', we need to mark its parents that they could be boundaries.
3002          */
3003
3004         for (l = c->parents; l; l = l->next) {
3005                 struct object *p;
3006                 p = &(l->item->object);
3007                 if (p->flags & (CHILD_SHOWN | SHOWN))
3008                         continue;
3009                 p->flags |= CHILD_SHOWN;
3010                 gc_boundary(&revs->boundary_commits);
3011                 add_object_array(p, NULL, &revs->boundary_commits);
3012         }
3013
3014         return c;
3015 }
3016
3017 struct commit *get_revision(struct rev_info *revs)
3018 {
3019         struct commit *c;
3020         struct commit_list *reversed;
3021
3022         if (revs->reverse) {
3023                 reversed = NULL;
3024                 while ((c = get_revision_internal(revs))) {
3025                         commit_list_insert(c, &reversed);
3026                 }
3027                 revs->commits = reversed;
3028                 revs->reverse = 0;
3029                 revs->reverse_output_stage = 1;
3030         }
3031
3032         if (revs->reverse_output_stage)
3033                 return pop_commit(&revs->commits);
3034
3035         c = get_revision_internal(revs);
3036         if (c && revs->graph)
3037                 graph_update(revs->graph, c);
3038         return c;
3039 }
3040
3041 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
3042 {
3043         if (commit->object.flags & BOUNDARY)
3044                 return "-";
3045         else if (commit->object.flags & UNINTERESTING)
3046                 return "^";
3047         else if (commit->object.flags & PATCHSAME)
3048                 return "=";
3049         else if (!revs || revs->left_right) {
3050                 if (commit->object.flags & SYMMETRIC_LEFT)
3051                         return "<";
3052                 else
3053                         return ">";
3054         } else if (revs->graph)
3055                 return "*";
3056         else if (revs->cherry_mark)
3057                 return "+";
3058         return "";
3059 }
3060
3061 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
3062 {
3063         char *mark = get_revision_mark(revs, commit);
3064         if (!strlen(mark))
3065                 return;
3066         fputs(mark, stdout);
3067         putchar(' ');
3068 }