summaryrefslogtreecommitdiff
path: root/revision.c
blob: 1d89d72738ff917d29373d50c2c2cc9bbd10b2c0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
#include "cache.h"
#include "tag.h"
#include "blob.h"
#include "tree.h"
#include "commit.h"
#include "diff.h"
#include "refs.h"
#include "revision.h"

static char *path_name(struct name_path *path, const char *name)
{
	struct name_path *p;
	char *n, *m;
	int nlen = strlen(name);
	int len = nlen + 1;

	for (p = path; p; p = p->up) {
		if (p->elem_len)
			len += p->elem_len + 1;
	}
	n = xmalloc(len);
	m = n + len - (nlen + 1);
	strcpy(m, name);
	for (p = path; p; p = p->up) {
		if (p->elem_len) {
			m -= p->elem_len + 1;
			memcpy(m, p->elem, p->elem_len);
			m[p->elem_len] = '/';
		}
	}
	return n;
}

void add_object(struct object *obj,
		struct object_array *p,
		struct name_path *path,
		const char *name)
{
	add_object_array(obj, path_name(path, name), p);
}

static void mark_blob_uninteresting(struct blob *blob)
{
	if (blob->object.flags & UNINTERESTING)
		return;
	blob->object.flags |= UNINTERESTING;
}

void mark_tree_uninteresting(struct tree *tree)
{
	struct tree_desc desc;
	struct name_entry entry;
	struct object *obj = &tree->object;

	if (obj->flags & UNINTERESTING)
		return;
	obj->flags |= UNINTERESTING;
	if (!has_sha1_file(obj->sha1))
		return;
	if (parse_tree(tree) < 0)
		die("bad tree %s", sha1_to_hex(obj->sha1));

	desc.buf = tree->buffer;
	desc.size = tree->size;
	while (tree_entry(&desc, &entry)) {
		if (S_ISDIR(entry.mode))
			mark_tree_uninteresting(lookup_tree(entry.sha1));
		else
			mark_blob_uninteresting(lookup_blob(entry.sha1));
	}

	/*
	 * We don't care about the tree any more
	 * after it has been marked uninteresting.
	 */
	free(tree->buffer);
	tree->buffer = NULL;
}

void mark_parents_uninteresting(struct commit *commit)
{
	struct commit_list *parents = commit->parents;

	while (parents) {
		struct commit *commit = parents->item;
		if (!(commit->object.flags & UNINTERESTING)) {
			commit->object.flags |= UNINTERESTING;

			/*
			 * Normally we haven't parsed the parent
			 * yet, so we won't have a parent of a parent
			 * here. However, it may turn out that we've
			 * reached this commit some other way (where it
			 * wasn't uninteresting), in which case we need
			 * to mark its parents recursively too..
			 */
			if (commit->parents)
				mark_parents_uninteresting(commit);
		}

		/*
		 * A missing commit is ok iff its parent is marked
		 * uninteresting.
		 *
		 * We just mark such a thing parsed, so that when
		 * it is popped next time around, we won't be trying
		 * to parse it and get an error.
		 */
		if (!has_sha1_file(commit->object.sha1))
			commit->object.parsed = 1;
		parents = parents->next;
	}
}

void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
{
	add_object_array(obj, name, &revs->pending);
}

static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
{
	struct object *object;

	object = parse_object(sha1);
	if (!object)
		die("bad object %s", name);
	object->flags |= flags;
	return object;
}

static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
{
	unsigned long flags = object->flags;

	/*
	 * Tag object? Look what it points to..
	 */
	while (object->type == OBJ_TAG) {
		struct tag *tag = (struct tag *) object;
		if (revs->tag_objects && !(flags & UNINTERESTING))
			add_pending_object(revs, object, tag->tag);
		object = parse_object(tag->tagged->sha1);
		if (!object)
			die("bad object %s", sha1_to_hex(tag->tagged->sha1));
	}

	/*
	 * Commit object? Just return it, we'll do all the complex
	 * reachability crud.
	 */
	if (object->type == OBJ_COMMIT) {
		struct commit *commit = (struct commit *)object;
		if (parse_commit(commit) < 0)
			die("unable to parse commit %s", name);
		if (flags & UNINTERESTING) {
			commit->object.flags |= UNINTERESTING;
			mark_parents_uninteresting(commit);
			revs->limited = 1;
		}
		return commit;
	}

	/*
	 * Tree object? Either mark it uniniteresting, or add it
	 * to the list of objects to look at later..
	 */
	if (object->type == OBJ_TREE) {
		struct tree *tree = (struct tree *)object;
		if (!revs->tree_objects)
			return NULL;
		if (flags & UNINTERESTING) {
			mark_tree_uninteresting(tree);
			return NULL;
		}
		add_pending_object(revs, object, "");
		return NULL;
	}

	/*
	 * Blob object? You know the drill by now..
	 */
	if (object->type == OBJ_BLOB) {
		struct blob *blob = (struct blob *)object;
		if (!revs->blob_objects)
			return NULL;
		if (flags & UNINTERESTING) {
			mark_blob_uninteresting(blob);
			return NULL;
		}
		add_pending_object(revs, object, "");
		return NULL;
	}
	die("%s is unknown object", name);
}

static int everybody_uninteresting(struct commit_list *orig)
{
	struct commit_list *list = orig;
	while (list) {
		struct commit *commit = list->item;
		list = list->next;
		if (commit->object.flags & UNINTERESTING)
			continue;
		return 0;
	}
	return 1;
}

static int tree_difference = REV_TREE_SAME;

static void file_add_remove(struct diff_options *options,
		    int addremove, unsigned mode,
		    const unsigned char *sha1,
		    const char *base, const char *path)
{
	int diff = REV_TREE_DIFFERENT;

	/*
	 * Is it an add of a new file? It means that the old tree
	 * didn't have it at all, so we will turn "REV_TREE_SAME" ->
	 * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
	 * (and if it already was "REV_TREE_NEW", we'll keep it
	 * "REV_TREE_NEW" of course).
	 */
	if (addremove == '+') {
		diff = tree_difference;
		if (diff != REV_TREE_SAME)
			return;
		diff = REV_TREE_NEW;
	}
	tree_difference = diff;
}

static void file_change(struct diff_options *options,
		 unsigned old_mode, unsigned new_mode,
		 const unsigned char *old_sha1,
		 const unsigned char *new_sha1,
		 const char *base, const char *path)
{
	tree_difference = REV_TREE_DIFFERENT;
}

int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
{
	if (!t1)
		return REV_TREE_NEW;
	if (!t2)
		return REV_TREE_DIFFERENT;
	tree_difference = REV_TREE_SAME;
	if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
			   &revs->pruning) < 0)
		return REV_TREE_DIFFERENT;
	return tree_difference;
}

int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
{
	int retval;
	void *tree;
	struct tree_desc empty, real;

	if (!t1)
		return 0;

	tree = read_object_with_reference(t1->object.sha1, tree_type, &real.size, NULL);
	if (!tree)
		return 0;
	real.buf = tree;

	empty.buf = "";
	empty.size = 0;

	tree_difference = 0;
	retval = diff_tree(&empty, &real, "", &revs->pruning);
	free(tree);

	return retval >= 0 && !tree_difference;
}

static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
{
	struct commit_list **pp, *parent;
	int tree_changed = 0, tree_same = 0;

	if (!commit->tree)
		return;

	if (!commit->parents) {
		if (!rev_same_tree_as_empty(revs, commit->tree))
			commit->object.flags |= TREECHANGE;
		return;
	}

	pp = &commit->parents;
	while ((parent = *pp) != NULL) {
		struct commit *p = parent->item;

		parse_commit(p);
		switch (rev_compare_tree(revs, p->tree, commit->tree)) {
		case REV_TREE_SAME:
			tree_same = 1;
			if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
				/* Even if a merge with an uninteresting
				 * side branch brought the entire change
				 * we are interested in, we do not want
				 * to lose the other branches of this
				 * merge, so we just keep going.
				 */
				pp = &parent->next;
				continue;
			}
			parent->next = NULL;
			commit->parents = parent;
			return;

		case REV_TREE_NEW:
			if (revs->remove_empty_trees &&
			    rev_same_tree_as_empty(revs, p->tree)) {
				/* We are adding all the specified
				 * paths from this parent, so the
				 * history beyond this parent is not
				 * interesting.  Remove its parents
				 * (they are grandparents for us).
				 * IOW, we pretend this parent is a
				 * "root" commit.
				 */
				parse_commit(p);
				p->parents = NULL;
			}
		/* fallthrough */
		case REV_TREE_DIFFERENT:
			tree_changed = 1;
			pp = &parent->next;
			continue;
		}
		die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
	}
	if (tree_changed && !tree_same)
		commit->object.flags |= TREECHANGE;
}

static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
{
	struct commit_list *parent = commit->parents;

	if (commit->object.flags & ADDED)
		return;
	commit->object.flags |= ADDED;

	/*
	 * If the commit is uninteresting, don't try to
	 * prune parents - we want the maximal uninteresting
	 * set.
	 *
	 * Normally we haven't parsed the parent
	 * yet, so we won't have a parent of a parent
	 * here. However, it may turn out that we've
	 * reached this commit some other way (where it
	 * wasn't uninteresting), in which case we need
	 * to mark its parents recursively too..
	 */
	if (commit->object.flags & UNINTERESTING) {
		while (parent) {
			struct commit *p = parent->item;
			parent = parent->next;
			parse_commit(p);
			p->object.flags |= UNINTERESTING;
			if (p->parents)
				mark_parents_uninteresting(p);
			if (p->object.flags & SEEN)
				continue;
			p->object.flags |= SEEN;
			insert_by_date(p, list);
		}
		return;
	}

	/*
	 * Ok, the commit wasn't uninteresting. Try to
	 * simplify the commit history and find the parent
	 * that has no differences in the path set if one exists.
	 */
	if (revs->prune_fn)
		revs->prune_fn(revs, commit);

	if (revs->no_walk)
		return;

	parent = commit->parents;
	while (parent) {
		struct commit *p = parent->item;

		parent = parent->next;

		parse_commit(p);
		if (p->object.flags & SEEN)
			continue;
		p->object.flags |= SEEN;
		insert_by_date(p, list);
	}
}

static void limit_list(struct rev_info *revs)
{
	struct commit_list *list = revs->commits;
	struct commit_list *newlist = NULL;
	struct commit_list **p = &newlist;

	while (list) {
		struct commit_list *entry = list;
		struct commit *commit = list->item;
		struct object *obj = &commit->object;

		list = list->next;
		free(entry);

		if (revs->max_age != -1 && (commit->date < revs->max_age))
			obj->flags |= UNINTERESTING;
		if (revs->unpacked && has_sha1_pack(obj->sha1))
			obj->flags |= UNINTERESTING;
		add_parents_to_list(revs, commit, &list);
		if (obj->flags & UNINTERESTING) {
			mark_parents_uninteresting(commit);
			if (everybody_uninteresting(list))
				break;
			continue;
		}
		if (revs->min_age != -1 && (commit->date > revs->min_age))
			continue;
		p = &commit_list_insert(commit, p)->next;
	}
	if (revs->boundary) {
		/* mark the ones that are on the result list first */
		for (list = newlist; list; list = list->next) {
			struct commit *commit = list->item;
			commit->object.flags |= TMP_MARK;
		}
		for (list = newlist; list; list = list->next) {
			struct commit *commit = list->item;
			struct object *obj = &commit->object;
			struct commit_list *parent;
			if (obj->flags & UNINTERESTING)
				continue;
			for (parent = commit->parents;
			     parent;
			     parent = parent->next) {
				struct commit *pcommit = parent->item;
				if (!(pcommit->object.flags & UNINTERESTING))
					continue;
				pcommit->object.flags |= BOUNDARY;
				if (pcommit->object.flags & TMP_MARK)
					continue;
				pcommit->object.flags |= TMP_MARK;
				p = &commit_list_insert(pcommit, p)->next;
			}
		}
		for (list = newlist; list; list = list->next) {
			struct commit *commit = list->item;
			commit->object.flags &= ~TMP_MARK;
		}
	}
	revs->commits = newlist;
}

static int all_flags;
static struct rev_info *all_revs;

static int handle_one_ref(const char *path, const unsigned char *sha1)
{
	struct object *object = get_reference(all_revs, path, sha1, all_flags);
	add_pending_object(all_revs, object, "");
	return 0;
}

static void handle_all(struct rev_info *revs, unsigned flags)
{
	all_revs = revs;
	all_flags = flags;
	for_each_ref(handle_one_ref);
}

static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
{
	unsigned char sha1[20];
	struct object *it;
	struct commit *commit;
	struct commit_list *parents;

	if (*arg == '^') {
		flags ^= UNINTERESTING;
		arg++;
	}
	if (get_sha1(arg, sha1))
		return 0;
	while (1) {
		it = get_reference(revs, arg, sha1, 0);
		if (it->type != OBJ_TAG)
			break;
		hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
	}
	if (it->type != OBJ_COMMIT)
		return 0;
	commit = (struct commit *)it;
	for (parents = commit->parents; parents; parents = parents->next) {
		it = &parents->item->object;
		it->flags |= flags;
		add_pending_object(revs, it, arg);
	}
	return 1;
}

void init_revisions(struct rev_info *revs, const char *prefix)
{
	memset(revs, 0, sizeof(*revs));

	revs->abbrev = DEFAULT_ABBREV;
	revs->ignore_merges = 1;
	revs->simplify_history = 1;
	revs->pruning.recursive = 1;
	revs->pruning.add_remove = file_add_remove;
	revs->pruning.change = file_change;
	revs->lifo = 1;
	revs->dense = 1;
	revs->prefix = prefix;
	revs->max_age = -1;
	revs->min_age = -1;
	revs->max_count = -1;

	revs->prune_fn = NULL;
	revs->prune_data = NULL;

	revs->topo_setter = topo_sort_default_setter;
	revs->topo_getter = topo_sort_default_getter;

	revs->commit_format = CMIT_FMT_DEFAULT;

	diff_setup(&revs->diffopt);
}

static void add_pending_commit_list(struct rev_info *revs,
                                    struct commit_list *commit_list,
                                    unsigned int flags)
{
	while (commit_list) {
		struct object *object = &commit_list->item->object;
		object->flags |= flags;
		add_pending_object(revs, object, sha1_to_hex(object->sha1));
		commit_list = commit_list->next;
	}
}

static void prepare_show_merge(struct rev_info *revs)
{
	struct commit_list *bases;
	struct commit *head, *other;
	unsigned char sha1[20];
	const char **prune = NULL;
	int i, prune_num = 1; /* counting terminating NULL */

	if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
		die("--merge without HEAD?");
	if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
		die("--merge without MERGE_HEAD?");
	add_pending_object(revs, &head->object, "HEAD");
	add_pending_object(revs, &other->object, "MERGE_HEAD");
	bases = get_merge_bases(head, other, 1);
	while (bases) {
		struct commit *it = bases->item;
		struct commit_list *n = bases->next;
		free(bases);
		bases = n;
		it->object.flags |= UNINTERESTING;
		add_pending_object(revs, &it->object, "(merge-base)");
	}

	if (!active_nr)
		read_cache();
	for (i = 0; i < active_nr; i++) {
		struct cache_entry *ce = active_cache[i];
		if (!ce_stage(ce))
			continue;
		if (ce_path_match(ce, revs->prune_data)) {
			prune_num++;
			prune = xrealloc(prune, sizeof(*prune) * prune_num);
			prune[prune_num-2] = ce->name;
			prune[prune_num-1] = NULL;
		}
		while ((i+1 < active_nr) &&
		       ce_same_name(ce, active_cache[i+1]))
			i++;
	}
	revs->prune_data = prune;
}

/*
 * Parse revision information, filling in the "rev_info" structure,
 * and removing the used arguments from the argument list.
 *
 * Returns the number of arguments left that weren't recognized
 * (which are also moved to the head of the argument list)
 */
int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
{
	int i, flags, seen_dashdash, show_merge;
	const char **unrecognized = argv + 1;
	int left = 1;

	/* First, search for "--" */
	seen_dashdash = 0;
	for (i = 1; i < argc; i++) {
		const char *arg = argv[i];
		if (strcmp(arg, "--"))
			continue;
		argv[i] = NULL;
		argc = i;
		revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
		seen_dashdash = 1;
		break;
	}

	flags = show_merge = 0;
	for (i = 1; i < argc; i++) {
		struct object *object;
		const char *arg = argv[i];
		unsigned char sha1[20];
		char *dotdot;
		int local_flags;

		if (*arg == '-') {
			int opts;
			if (!strncmp(arg, "--max-count=", 12)) {
				revs->max_count = atoi(arg + 12);
				continue;
			}
			/* accept -<digit>, like traditional "head" */
			if ((*arg == '-') && isdigit(arg[1])) {
				revs->max_count = atoi(arg + 1);
				continue;
			}
			if (!strcmp(arg, "-n")) {
				if (argc <= i + 1)
					die("-n requires an argument");
				revs->max_count = atoi(argv[++i]);
				continue;
			}
			if (!strncmp(arg,"-n",2)) {
				revs->max_count = atoi(arg + 2);
				continue;
			}
			if (!strncmp(arg, "--max-age=", 10)) {
				revs->max_age = atoi(arg + 10);
				continue;
			}
			if (!strncmp(arg, "--since=", 8)) {
				revs->max_age = approxidate(arg + 8);
				continue;
			}
			if (!strncmp(arg, "--after=", 8)) {
				revs->max_age = approxidate(arg + 8);
				continue;
			}
			if (!strncmp(arg, "--min-age=", 10)) {
				revs->min_age = atoi(arg + 10);
				continue;
			}
			if (!strncmp(arg, "--before=", 9)) {
				revs->min_age = approxidate(arg + 9);
				continue;
			}
			if (!strncmp(arg, "--until=", 8)) {
				revs->min_age = approxidate(arg + 8);
				continue;
			}
			if (!strcmp(arg, "--all")) {
				handle_all(revs, flags);
				continue;
			}
			if (!strcmp(arg, "--not")) {
				flags ^= UNINTERESTING;
				continue;
			}
			if (!strcmp(arg, "--default")) {
				if (++i >= argc)
					die("bad --default argument");
				def = argv[i];
				continue;
			}
			if (!strcmp(arg, "--merge")) {
				show_merge = 1;
				continue;
			}
			if (!strcmp(arg, "--topo-order")) {
				revs->topo_order = 1;
				continue;
			}
			if (!strcmp(arg, "--date-order")) {
				revs->lifo = 0;
				revs->topo_order = 1;
				continue;
			}
			if (!strcmp(arg, "--parents")) {
				revs->parents = 1;
				continue;
			}
			if (!strcmp(arg, "--dense")) {
				revs->dense = 1;
				continue;
			}
			if (!strcmp(arg, "--sparse")) {
				revs->dense = 0;
				continue;
			}
			if (!strcmp(arg, "--remove-empty")) {
				revs->remove_empty_trees = 1;
				continue;
			}
			if (!strcmp(arg, "--no-merges")) {
				revs->no_merges = 1;
				continue;
			}
			if (!strcmp(arg, "--boundary")) {
				revs->boundary = 1;
				continue;
			}
			if (!strcmp(arg, "--objects")) {
				revs->tag_objects = 1;
				revs->tree_objects = 1;
				revs->blob_objects = 1;
				continue;
			}
			if (!strcmp(arg, "--objects-edge")) {
				revs->tag_objects = 1;
				revs->tree_objects = 1;
				revs->blob_objects = 1;
				revs->edge_hint = 1;
				continue;
			}
			if (!strcmp(arg, "--unpacked")) {
				revs->unpacked = 1;
				continue;
			}
			if (!strcmp(arg, "-r")) {
				revs->diff = 1;
				revs->diffopt.recursive = 1;
				continue;
			}
			if (!strcmp(arg, "-t")) {
				revs->diff = 1;
				revs->diffopt.recursive = 1;
				revs->diffopt.tree_in_recursive = 1;
				continue;
			}
			if (!strcmp(arg, "-m")) {
				revs->ignore_merges = 0;
				continue;
			}
			if (!strcmp(arg, "-c")) {
				revs->diff = 1;
				revs->dense_combined_merges = 0;
				revs->combine_merges = 1;
				continue;
			}
			if (!strcmp(arg, "--cc")) {
				revs->diff = 1;
				revs->dense_combined_merges = 1;
				revs->combine_merges = 1;
				continue;
			}
			if (!strcmp(arg, "-v")) {
				revs->verbose_header = 1;
				continue;
			}
			if (!strncmp(arg, "--pretty", 8)) {
				revs->verbose_header = 1;
				revs->commit_format = get_commit_format(arg+8);
				continue;
			}
			if (!strcmp(arg, "--root")) {
				revs->show_root_diff = 1;
				continue;
			}
			if (!strcmp(arg, "--no-commit-id")) {
				revs->no_commit_id = 1;
				continue;
			}
			if (!strcmp(arg, "--always")) {
				revs->always_show_header = 1;
				continue;
			}
			if (!strcmp(arg, "--no-abbrev")) {
				revs->abbrev = 0;
				continue;
			}
			if (!strcmp(arg, "--abbrev")) {
				revs->abbrev = DEFAULT_ABBREV;
				continue;
			}
			if (!strncmp(arg, "--abbrev=", 9)) {
				revs->abbrev = strtoul(arg + 9, NULL, 10);
				if (revs->abbrev < MINIMUM_ABBREV)
					revs->abbrev = MINIMUM_ABBREV;
				else if (revs->abbrev > 40)
					revs->abbrev = 40;
				continue;
			}
			if (!strcmp(arg, "--abbrev-commit")) {
				revs->abbrev_commit = 1;
				continue;
			}
			if (!strcmp(arg, "--full-diff")) {
				revs->diff = 1;
				revs->full_diff = 1;
				continue;
			}
			if (!strcmp(arg, "--full-history")) {
				revs->simplify_history = 0;
				continue;
			}
			opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
			if (opts > 0) {
				revs->diff = 1;
				i += opts - 1;
				continue;
			}
			*unrecognized++ = arg;
			left++;
			continue;
		}
		dotdot = strstr(arg, "..");
		if (dotdot) {
			unsigned char from_sha1[20];
			const char *next = dotdot + 2;
			const char *this = arg;
			int symmetric = *next == '.';
			unsigned int flags_exclude = flags ^ UNINTERESTING;

			*dotdot = 0;
			next += symmetric;

			if (!*next)
				next = "HEAD";
			if (dotdot == arg)
				this = "HEAD";
			if (!get_sha1(this, from_sha1) &&
			    !get_sha1(next, sha1)) {
				struct commit *a, *b;
				struct commit_list *exclude;

				a = lookup_commit_reference(from_sha1);
				b = lookup_commit_reference(sha1);
				if (!a || !b) {
					die(symmetric ?
					    "Invalid symmetric difference expression %s...%s" :
					    "Invalid revision range %s..%s",
					    arg, next);
				}

				if (!seen_dashdash) {
					*dotdot = '.';
					verify_non_filename(revs->prefix, arg);
				}

				if (symmetric) {
					exclude = get_merge_bases(a, b, 1);
					add_pending_commit_list(revs, exclude,
					                        flags_exclude);
					free_commit_list(exclude);
					a->object.flags |= flags;
				} else
					a->object.flags |= flags_exclude;
				b->object.flags |= flags;
				add_pending_object(revs, &a->object, this);
				add_pending_object(revs, &b->object, next);
				continue;
			}
			*dotdot = '.';
		}
		dotdot = strstr(arg, "^@");
		if (dotdot && !dotdot[2]) {
			*dotdot = 0;
			if (add_parents_only(revs, arg, flags))
				continue;
			*dotdot = '^';
		}
		local_flags = 0;
		if (*arg == '^') {
			local_flags = UNINTERESTING;
			arg++;
		}
		if (get_sha1(arg, sha1)) {
			int j;

			if (seen_dashdash || local_flags)
				die("bad revision '%s'", arg);

			/* If we didn't have a "--":
			 * (1) all filenames must exist;
			 * (2) all rev-args must not be interpretable
			 *     as a valid filename.
			 * but the latter we have checked in the main loop.
			 */
			for (j = i; j < argc; j++)
				verify_filename(revs->prefix, argv[j]);

			revs->prune_data = get_pathspec(revs->prefix, argv + i);
			break;
		}
		if (!seen_dashdash)
			verify_non_filename(revs->prefix, arg);
		object = get_reference(revs, arg, sha1, flags ^ local_flags);
		add_pending_object(revs, object, arg);
	}
	if (show_merge)
		prepare_show_merge(revs);
	if (def && !revs->pending.nr) {
		unsigned char sha1[20];
		struct object *object;
		if (get_sha1(def, sha1))
			die("bad default revision '%s'", def);
		object = get_reference(revs, def, sha1, 0);
		add_pending_object(revs, object, def);
	}

	if (revs->topo_order || revs->unpacked)
		revs->limited = 1;

	if (revs->prune_data) {
		diff_tree_setup_paths(revs->prune_data, &revs->pruning);
		revs->prune_fn = try_to_simplify_commit;
		if (!revs->full_diff)
			diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
	}
	if (revs->combine_merges) {
		revs->ignore_merges = 0;
		if (revs->dense_combined_merges && !revs->diffopt.output_format)
			revs->diffopt.output_format = DIFF_FORMAT_PATCH;
	}
	revs->diffopt.abbrev = revs->abbrev;
	if (diff_setup_done(&revs->diffopt) < 0)
		die("diff_setup_done failed");

	return left;
}

void prepare_revision_walk(struct rev_info *revs)
{
	int nr = revs->pending.nr;
	struct object_array_entry *list = revs->pending.objects;

	revs->pending.nr = 0;
	revs->pending.alloc = 0;
	revs->pending.objects = NULL;
	while (--nr >= 0) {
		struct commit *commit = handle_commit(revs, list->item, list->name);
		if (commit) {
			if (!(commit->object.flags & SEEN)) {
				commit->object.flags |= SEEN;
				insert_by_date(commit, &revs->commits);
			}
		}
		list++;
	}

	if (revs->no_walk)
		return;
	if (revs->limited)
		limit_list(revs);
	if (revs->topo_order)
		sort_in_topological_order_fn(&revs->commits, revs->lifo,
					     revs->topo_setter,
					     revs->topo_getter);
}

static int rewrite_one(struct rev_info *revs, struct commit **pp)
{
	for (;;) {
		struct commit *p = *pp;
		if (!revs->limited)
			add_parents_to_list(revs, p, &revs->commits);
		if (p->parents && p->parents->next)
			return 0;
		if (p->object.flags & (TREECHANGE | UNINTERESTING))
			return 0;
		if (!p->parents)
			return -1;
		*pp = p->parents->item;
	}
}

static void rewrite_parents(struct rev_info *revs, struct commit *commit)
{
	struct commit_list **pp = &commit->parents;
	while (*pp) {
		struct commit_list *parent = *pp;
		if (rewrite_one(revs, &parent->item) < 0) {
			*pp = parent->next;
			continue;
		}
		pp = &parent->next;
	}
}

static void mark_boundary_to_show(struct commit *commit)
{
	struct commit_list *p = commit->parents;
	while (p) {
		commit = p->item;
		p = p->next;
		if (commit->object.flags & BOUNDARY)
			commit->object.flags |= BOUNDARY_SHOW;
	}
}

struct commit *get_revision(struct rev_info *revs)
{
	struct commit_list *list = revs->commits;

	if (!list)
		return NULL;

	/* Check the max_count ... */
	switch (revs->max_count) {
	case -1:
		break;
	case 0:
		return NULL;
	default:
		revs->max_count--;
	}

	do {
		struct commit_list *entry = revs->commits;
		struct commit *commit = entry->item;

		revs->commits = entry->next;
		free(entry);

		/*
		 * If we haven't done the list limiting, we need to look at
		 * the parents here. We also need to do the date-based limiting
		 * that we'd otherwise have done in limit_list().
		 */
		if (!revs->limited) {
			if ((revs->unpacked &&
			     has_sha1_pack(commit->object.sha1)) ||
			    (revs->max_age != -1 &&
			     (commit->date < revs->max_age)))
				continue;
			add_parents_to_list(revs, commit, &revs->commits);
		}
		if (commit->object.flags & SHOWN)
			continue;

		/* We want to show boundary commits only when their
		 * children are shown.  When path-limiter is in effect,
		 * rewrite_parents() drops some commits from getting shown,
		 * and there is no point showing boundary parents that
		 * are not shown.  After rewrite_parents() rewrites the
		 * parents of a commit that is shown, we mark the boundary
		 * parents with BOUNDARY_SHOW.
		 */
		if (commit->object.flags & BOUNDARY_SHOW) {
			commit->object.flags |= SHOWN;
			return commit;
		}
		if (commit->object.flags & UNINTERESTING)
			continue;
		if (revs->min_age != -1 && (commit->date > revs->min_age))
			continue;
		if (revs->no_merges &&
		    commit->parents && commit->parents->next)
			continue;
		if (revs->prune_fn && revs->dense) {
			/* Commit without changes? */
			if (!(commit->object.flags & TREECHANGE)) {
				/* drop merges unless we want parenthood */
				if (!revs->parents)
					continue;
				/* non-merge - always ignore it */
				if (!commit->parents || !commit->parents->next)
					continue;
			}
			if (revs->parents)
				rewrite_parents(revs, commit);
		}
		if (revs->boundary)
			mark_boundary_to_show(commit);
		commit->object.flags |= SHOWN;
		return commit;
	} while (revs->commits);
	return NULL;
}