Merge branch 'lt/xsha1' into next
[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
10 static char *path_name(struct name_path *path, const char *name)
11 {
12         struct name_path *p;
13         char *n, *m;
14         int nlen = strlen(name);
15         int len = nlen + 1;
16
17         for (p = path; p; p = p->up) {
18                 if (p->elem_len)
19                         len += p->elem_len + 1;
20         }
21         n = xmalloc(len);
22         m = n + len - (nlen + 1);
23         strcpy(m, name);
24         for (p = path; p; p = p->up) {
25                 if (p->elem_len) {
26                         m -= p->elem_len + 1;
27                         memcpy(m, p->elem, p->elem_len);
28                         m[p->elem_len] = '/';
29                 }
30         }
31         return n;
32 }
33
34 struct object_list **add_object(struct object *obj,
35                                        struct object_list **p,
36                                        struct name_path *path,
37                                        const char *name)
38 {
39         struct object_list *entry = xmalloc(sizeof(*entry));
40         entry->item = obj;
41         entry->next = *p;
42         entry->name = path_name(path, name);
43         *p = entry;
44         return &entry->next;
45 }
46
47 static void mark_blob_uninteresting(struct blob *blob)
48 {
49         if (blob->object.flags & UNINTERESTING)
50                 return;
51         blob->object.flags |= UNINTERESTING;
52 }
53
54 void mark_tree_uninteresting(struct tree *tree)
55 {
56         struct object *obj = &tree->object;
57         struct tree_entry_list *entry;
58
59         if (obj->flags & UNINTERESTING)
60                 return;
61         obj->flags |= UNINTERESTING;
62         if (!has_sha1_file(obj->sha1))
63                 return;
64         if (parse_tree(tree) < 0)
65                 die("bad tree %s", sha1_to_hex(obj->sha1));
66         entry = tree->entries;
67         tree->entries = NULL;
68         while (entry) {
69                 struct tree_entry_list *next = entry->next;
70                 if (entry->directory)
71                         mark_tree_uninteresting(entry->item.tree);
72                 else
73                         mark_blob_uninteresting(entry->item.blob);
74                 free(entry);
75                 entry = next;
76         }
77 }
78
79 void mark_parents_uninteresting(struct commit *commit)
80 {
81         struct commit_list *parents = commit->parents;
82
83         while (parents) {
84                 struct commit *commit = parents->item;
85                 if (!(commit->object.flags & UNINTERESTING)) {
86                         commit->object.flags |= UNINTERESTING;
87
88                         /*
89                          * Normally we haven't parsed the parent
90                          * yet, so we won't have a parent of a parent
91                          * here. However, it may turn out that we've
92                          * reached this commit some other way (where it
93                          * wasn't uninteresting), in which case we need
94                          * to mark its parents recursively too..
95                          */
96                         if (commit->parents)
97                                 mark_parents_uninteresting(commit);
98                 }
99
100                 /*
101                  * A missing commit is ok iff its parent is marked
102                  * uninteresting.
103                  *
104                  * We just mark such a thing parsed, so that when
105                  * it is popped next time around, we won't be trying
106                  * to parse it and get an error.
107                  */
108                 if (!has_sha1_file(commit->object.sha1))
109                         commit->object.parsed = 1;
110                 parents = parents->next;
111         }
112 }
113
114 static void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
115 {
116         add_object(obj, &revs->pending_objects, NULL, name);
117 }
118
119 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
120 {
121         struct object *object;
122
123         object = parse_object(sha1);
124         if (!object)
125                 die("bad object %s", name);
126         object->flags |= flags;
127         return object;
128 }
129
130 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
131 {
132         unsigned long flags = object->flags;
133
134         /*
135          * Tag object? Look what it points to..
136          */
137         while (object->type == tag_type) {
138                 struct tag *tag = (struct tag *) object;
139                 if (revs->tag_objects && !(flags & UNINTERESTING))
140                         add_pending_object(revs, object, tag->tag);
141                 object = parse_object(tag->tagged->sha1);
142                 if (!object)
143                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
144         }
145
146         /*
147          * Commit object? Just return it, we'll do all the complex
148          * reachability crud.
149          */
150         if (object->type == commit_type) {
151                 struct commit *commit = (struct commit *)object;
152                 if (parse_commit(commit) < 0)
153                         die("unable to parse commit %s", name);
154                 if (flags & UNINTERESTING) {
155                         commit->object.flags |= UNINTERESTING;
156                         mark_parents_uninteresting(commit);
157                         revs->limited = 1;
158                 }
159                 return commit;
160         }
161
162         /*
163          * Tree object? Either mark it uniniteresting, or add it
164          * to the list of objects to look at later..
165          */
166         if (object->type == tree_type) {
167                 struct tree *tree = (struct tree *)object;
168                 if (!revs->tree_objects)
169                         return NULL;
170                 if (flags & UNINTERESTING) {
171                         mark_tree_uninteresting(tree);
172                         return NULL;
173                 }
174                 add_pending_object(revs, object, "");
175                 return NULL;
176         }
177
178         /*
179          * Blob object? You know the drill by now..
180          */
181         if (object->type == blob_type) {
182                 struct blob *blob = (struct blob *)object;
183                 if (!revs->blob_objects)
184                         return NULL;
185                 if (flags & UNINTERESTING) {
186                         mark_blob_uninteresting(blob);
187                         return NULL;
188                 }
189                 add_pending_object(revs, object, "");
190                 return NULL;
191         }
192         die("%s is unknown object", name);
193 }
194
195 static int everybody_uninteresting(struct commit_list *orig)
196 {
197         struct commit_list *list = orig;
198         while (list) {
199                 struct commit *commit = list->item;
200                 list = list->next;
201                 if (commit->object.flags & UNINTERESTING)
202                         continue;
203                 return 0;
204         }
205         return 1;
206 }
207
208 static int tree_difference = REV_TREE_SAME;
209
210 static void file_add_remove(struct diff_options *options,
211                     int addremove, unsigned mode,
212                     const unsigned char *sha1,
213                     const char *base, const char *path)
214 {
215         int diff = REV_TREE_DIFFERENT;
216
217         /*
218          * Is it an add of a new file? It means that the old tree
219          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
220          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
221          * (and if it already was "REV_TREE_NEW", we'll keep it
222          * "REV_TREE_NEW" of course).
223          */
224         if (addremove == '+') {
225                 diff = tree_difference;
226                 if (diff != REV_TREE_SAME)
227                         return;
228                 diff = REV_TREE_NEW;
229         }
230         tree_difference = diff;
231 }
232
233 static void file_change(struct diff_options *options,
234                  unsigned old_mode, unsigned new_mode,
235                  const unsigned char *old_sha1,
236                  const unsigned char *new_sha1,
237                  const char *base, const char *path)
238 {
239         tree_difference = REV_TREE_DIFFERENT;
240 }
241
242 int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
243 {
244         if (!t1)
245                 return REV_TREE_NEW;
246         if (!t2)
247                 return REV_TREE_DIFFERENT;
248         tree_difference = REV_TREE_SAME;
249         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
250                            &revs->pruning) < 0)
251                 return REV_TREE_DIFFERENT;
252         return tree_difference;
253 }
254
255 int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
256 {
257         int retval;
258         void *tree;
259         struct tree_desc empty, real;
260
261         if (!t1)
262                 return 0;
263
264         tree = read_object_with_reference(t1->object.sha1, tree_type, &real.size, NULL);
265         if (!tree)
266                 return 0;
267         real.buf = tree;
268
269         empty.buf = "";
270         empty.size = 0;
271
272         tree_difference = 0;
273         retval = diff_tree(&empty, &real, "", &revs->pruning);
274         free(tree);
275
276         return retval >= 0 && !tree_difference;
277 }
278
279 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
280 {
281         struct commit_list **pp, *parent;
282         int tree_changed = 0;
283
284         if (!commit->tree)
285                 return;
286
287         if (!commit->parents) {
288                 if (!rev_same_tree_as_empty(revs, commit->tree))
289                         commit->object.flags |= TREECHANGE;
290                 return;
291         }
292
293         pp = &commit->parents;
294         while ((parent = *pp) != NULL) {
295                 struct commit *p = parent->item;
296
297                 parse_commit(p);
298                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
299                 case REV_TREE_SAME:
300                         if (p->object.flags & UNINTERESTING) {
301                                 /* Even if a merge with an uninteresting
302                                  * side branch brought the entire change
303                                  * we are interested in, we do not want
304                                  * to lose the other branches of this
305                                  * merge, so we just keep going.
306                                  */
307                                 pp = &parent->next;
308                                 continue;
309                         }
310                         parent->next = NULL;
311                         commit->parents = parent;
312                         return;
313
314                 case REV_TREE_NEW:
315                         if (revs->remove_empty_trees &&
316                             rev_same_tree_as_empty(revs, p->tree)) {
317                                 /* We are adding all the specified
318                                  * paths from this parent, so the
319                                  * history beyond this parent is not
320                                  * interesting.  Remove its parents
321                                  * (they are grandparents for us).
322                                  * IOW, we pretend this parent is a
323                                  * "root" commit.
324                                  */
325                                 parse_commit(p);
326                                 p->parents = NULL;
327                         }
328                 /* fallthrough */
329                 case REV_TREE_DIFFERENT:
330                         tree_changed = 1;
331                         pp = &parent->next;
332                         continue;
333                 }
334                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
335         }
336         if (tree_changed)
337                 commit->object.flags |= TREECHANGE;
338 }
339
340 static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
341 {
342         struct commit_list *parent = commit->parents;
343
344         if (commit->object.flags & ADDED)
345                 return;
346         commit->object.flags |= ADDED;
347
348         /*
349          * If the commit is uninteresting, don't try to
350          * prune parents - we want the maximal uninteresting
351          * set.
352          *
353          * Normally we haven't parsed the parent
354          * yet, so we won't have a parent of a parent
355          * here. However, it may turn out that we've
356          * reached this commit some other way (where it
357          * wasn't uninteresting), in which case we need
358          * to mark its parents recursively too..
359          */
360         if (commit->object.flags & UNINTERESTING) {
361                 while (parent) {
362                         struct commit *p = parent->item;
363                         parent = parent->next;
364                         parse_commit(p);
365                         p->object.flags |= UNINTERESTING;
366                         if (p->parents)
367                                 mark_parents_uninteresting(p);
368                         if (p->object.flags & SEEN)
369                                 continue;
370                         p->object.flags |= SEEN;
371                         insert_by_date(p, list);
372                 }
373                 return;
374         }
375
376         /*
377          * Ok, the commit wasn't uninteresting. Try to
378          * simplify the commit history and find the parent
379          * that has no differences in the path set if one exists.
380          */
381         if (revs->prune_fn)
382                 revs->prune_fn(revs, commit);
383
384         if (revs->no_walk)
385                 return;
386
387         parent = commit->parents;
388         while (parent) {
389                 struct commit *p = parent->item;
390
391                 parent = parent->next;
392
393                 parse_commit(p);
394                 if (p->object.flags & SEEN)
395                         continue;
396                 p->object.flags |= SEEN;
397                 insert_by_date(p, list);
398         }
399 }
400
401 static void limit_list(struct rev_info *revs)
402 {
403         struct commit_list *list = revs->commits;
404         struct commit_list *newlist = NULL;
405         struct commit_list **p = &newlist;
406
407         while (list) {
408                 struct commit_list *entry = list;
409                 struct commit *commit = list->item;
410                 struct object *obj = &commit->object;
411
412                 list = list->next;
413                 free(entry);
414
415                 if (revs->max_age != -1 && (commit->date < revs->max_age))
416                         obj->flags |= UNINTERESTING;
417                 if (revs->unpacked && has_sha1_pack(obj->sha1))
418                         obj->flags |= UNINTERESTING;
419                 add_parents_to_list(revs, commit, &list);
420                 if (obj->flags & UNINTERESTING) {
421                         mark_parents_uninteresting(commit);
422                         if (everybody_uninteresting(list))
423                                 break;
424                         continue;
425                 }
426                 if (revs->min_age != -1 && (commit->date > revs->min_age))
427                         continue;
428                 p = &commit_list_insert(commit, p)->next;
429         }
430         if (revs->boundary) {
431                 /* mark the ones that are on the result list first */
432                 for (list = newlist; list; list = list->next) {
433                         struct commit *commit = list->item;
434                         commit->object.flags |= TMP_MARK;
435                 }
436                 for (list = newlist; list; list = list->next) {
437                         struct commit *commit = list->item;
438                         struct object *obj = &commit->object;
439                         struct commit_list *parent;
440                         if (obj->flags & UNINTERESTING)
441                                 continue;
442                         for (parent = commit->parents;
443                              parent;
444                              parent = parent->next) {
445                                 struct commit *pcommit = parent->item;
446                                 if (!(pcommit->object.flags & UNINTERESTING))
447                                         continue;
448                                 pcommit->object.flags |= BOUNDARY;
449                                 if (pcommit->object.flags & TMP_MARK)
450                                         continue;
451                                 pcommit->object.flags |= TMP_MARK;
452                                 p = &commit_list_insert(pcommit, p)->next;
453                         }
454                 }
455                 for (list = newlist; list; list = list->next) {
456                         struct commit *commit = list->item;
457                         commit->object.flags &= ~TMP_MARK;
458                 }
459         }
460         revs->commits = newlist;
461 }
462
463 static int all_flags;
464 static struct rev_info *all_revs;
465
466 static int handle_one_ref(const char *path, const unsigned char *sha1)
467 {
468         struct object *object = get_reference(all_revs, path, sha1, all_flags);
469         add_pending_object(all_revs, object, "");
470         return 0;
471 }
472
473 static void handle_all(struct rev_info *revs, unsigned flags)
474 {
475         all_revs = revs;
476         all_flags = flags;
477         for_each_ref(handle_one_ref);
478 }
479
480 void init_revisions(struct rev_info *revs)
481 {
482         memset(revs, 0, sizeof(*revs));
483
484         revs->abbrev = DEFAULT_ABBREV;
485         revs->ignore_merges = 1;
486         revs->pruning.recursive = 1;
487         revs->pruning.add_remove = file_add_remove;
488         revs->pruning.change = file_change;
489         revs->lifo = 1;
490         revs->dense = 1;
491         revs->prefix = setup_git_directory();
492         revs->max_age = -1;
493         revs->min_age = -1;
494         revs->max_count = -1;
495
496         revs->prune_fn = NULL;
497         revs->prune_data = NULL;
498
499         revs->topo_setter = topo_sort_default_setter;
500         revs->topo_getter = topo_sort_default_getter;
501
502         revs->commit_format = CMIT_FMT_DEFAULT;
503
504         diff_setup(&revs->diffopt);
505 }
506
507 /*
508  * Parse revision information, filling in the "rev_info" structure,
509  * and removing the used arguments from the argument list.
510  *
511  * Returns the number of arguments left that weren't recognized
512  * (which are also moved to the head of the argument list)
513  */
514 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
515 {
516         int i, flags, seen_dashdash;
517         const char **unrecognized = argv + 1;
518         int left = 1;
519
520         /* First, search for "--" */
521         seen_dashdash = 0;
522         for (i = 1; i < argc; i++) {
523                 const char *arg = argv[i];
524                 if (strcmp(arg, "--"))
525                         continue;
526                 argv[i] = NULL;
527                 argc = i;
528                 revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
529                 seen_dashdash = 1;
530                 break;
531         }
532
533         flags = 0;
534         for (i = 1; i < argc; i++) {
535                 struct object *object;
536                 const char *arg = argv[i];
537                 unsigned char sha1[20];
538                 char *dotdot;
539                 int local_flags;
540
541                 if (*arg == '-') {
542                         int opts;
543                         if (!strncmp(arg, "--max-count=", 12)) {
544                                 revs->max_count = atoi(arg + 12);
545                                 continue;
546                         }
547                         /* accept -<digit>, like traditilnal "head" */
548                         if ((*arg == '-') && isdigit(arg[1])) {
549                                 revs->max_count = atoi(arg + 1);
550                                 continue;
551                         }
552                         if (!strcmp(arg, "-n")) {
553                                 if (argc <= i + 1)
554                                         die("-n requires an argument");
555                                 revs->max_count = atoi(argv[++i]);
556                                 continue;
557                         }
558                         if (!strncmp(arg,"-n",2)) {
559                                 revs->max_count = atoi(arg + 2);
560                                 continue;
561                         }
562                         if (!strncmp(arg, "--max-age=", 10)) {
563                                 revs->max_age = atoi(arg + 10);
564                                 continue;
565                         }
566                         if (!strncmp(arg, "--since=", 8)) {
567                                 revs->max_age = approxidate(arg + 8);
568                                 continue;
569                         }
570                         if (!strncmp(arg, "--after=", 8)) {
571                                 revs->max_age = approxidate(arg + 8);
572                                 continue;
573                         }
574                         if (!strncmp(arg, "--min-age=", 10)) {
575                                 revs->min_age = atoi(arg + 10);
576                                 continue;
577                         }
578                         if (!strncmp(arg, "--before=", 9)) {
579                                 revs->min_age = approxidate(arg + 9);
580                                 continue;
581                         }
582                         if (!strncmp(arg, "--until=", 8)) {
583                                 revs->min_age = approxidate(arg + 8);
584                                 continue;
585                         }
586                         if (!strcmp(arg, "--all")) {
587                                 handle_all(revs, flags);
588                                 continue;
589                         }
590                         if (!strcmp(arg, "--not")) {
591                                 flags ^= UNINTERESTING;
592                                 continue;
593                         }
594                         if (!strcmp(arg, "--default")) {
595                                 if (++i >= argc)
596                                         die("bad --default argument");
597                                 def = argv[i];
598                                 continue;
599                         }
600                         if (!strcmp(arg, "--topo-order")) {
601                                 revs->topo_order = 1;
602                                 continue;
603                         }
604                         if (!strcmp(arg, "--date-order")) {
605                                 revs->lifo = 0;
606                                 revs->topo_order = 1;
607                                 continue;
608                         }
609                         if (!strcmp(arg, "--parents")) {
610                                 revs->parents = 1;
611                                 continue;
612                         }
613                         if (!strcmp(arg, "--dense")) {
614                                 revs->dense = 1;
615                                 continue;
616                         }
617                         if (!strcmp(arg, "--sparse")) {
618                                 revs->dense = 0;
619                                 continue;
620                         }
621                         if (!strcmp(arg, "--remove-empty")) {
622                                 revs->remove_empty_trees = 1;
623                                 continue;
624                         }
625                         if (!strcmp(arg, "--no-merges")) {
626                                 revs->no_merges = 1;
627                                 continue;
628                         }
629                         if (!strcmp(arg, "--boundary")) {
630                                 revs->boundary = 1;
631                                 continue;
632                         }
633                         if (!strcmp(arg, "--objects")) {
634                                 revs->tag_objects = 1;
635                                 revs->tree_objects = 1;
636                                 revs->blob_objects = 1;
637                                 continue;
638                         }
639                         if (!strcmp(arg, "--objects-edge")) {
640                                 revs->tag_objects = 1;
641                                 revs->tree_objects = 1;
642                                 revs->blob_objects = 1;
643                                 revs->edge_hint = 1;
644                                 continue;
645                         }
646                         if (!strcmp(arg, "--unpacked")) {
647                                 revs->unpacked = 1;
648                                 continue;
649                         }
650                         if (!strcmp(arg, "-r")) {
651                                 revs->diff = 1;
652                                 revs->diffopt.recursive = 1;
653                                 continue;
654                         }
655                         if (!strcmp(arg, "-t")) {
656                                 revs->diff = 1;
657                                 revs->diffopt.recursive = 1;
658                                 revs->diffopt.tree_in_recursive = 1;
659                                 continue;
660                         }
661                         if (!strcmp(arg, "-m")) {
662                                 revs->ignore_merges = 0;
663                                 continue;
664                         }
665                         if (!strcmp(arg, "-c")) {
666                                 revs->diff = 1;
667                                 revs->combine_merges = 1;
668                                 continue;
669                         }
670                         if (!strcmp(arg, "--cc")) {
671                                 revs->diff = 1;
672                                 revs->dense_combined_merges = 1;
673                                 revs->combine_merges = 1;
674                                 continue;
675                         }
676                         if (!strcmp(arg, "-v")) {
677                                 revs->verbose_header = 1;
678                                 continue;
679                         }
680                         if (!strncmp(arg, "--pretty", 8)) {
681                                 revs->verbose_header = 1;
682                                 revs->commit_format = get_commit_format(arg+8);
683                                 continue;
684                         }
685                         if (!strcmp(arg, "--root")) {
686                                 revs->show_root_diff = 1;
687                                 continue;
688                         }
689                         if (!strcmp(arg, "--no-commit-id")) {
690                                 revs->no_commit_id = 1;
691                                 continue;
692                         }
693                         if (!strcmp(arg, "--always")) {
694                                 revs->always_show_header = 1;
695                                 continue;
696                         }
697                         if (!strcmp(arg, "--no-abbrev")) {
698                                 revs->abbrev = 0;
699                                 continue;
700                         }
701                         if (!strcmp(arg, "--abbrev")) {
702                                 revs->abbrev = DEFAULT_ABBREV;
703                                 continue;
704                         }
705                         if (!strcmp(arg, "--abbrev-commit")) {
706                                 revs->abbrev_commit = 1;
707                                 continue;
708                         }
709                         if (!strcmp(arg, "--full-diff")) {
710                                 revs->diff = 1;
711                                 revs->full_diff = 1;
712                                 continue;
713                         }
714                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
715                         if (opts > 0) {
716                                 revs->diff = 1;
717                                 i += opts - 1;
718                                 continue;
719                         }
720                         *unrecognized++ = arg;
721                         left++;
722                         continue;
723                 }
724                 dotdot = strstr(arg, "..");
725                 if (dotdot) {
726                         unsigned char from_sha1[20];
727                         const char *next = dotdot + 2;
728                         const char *this = arg;
729                         *dotdot = 0;
730                         if (!*next)
731                                 next = "HEAD";
732                         if (dotdot == arg)
733                                 this = "HEAD";
734                         if (!get_sha1(this, from_sha1) &&
735                             !get_sha1(next, sha1)) {
736                                 struct object *exclude;
737                                 struct object *include;
738
739                                 exclude = get_reference(revs, this, from_sha1, flags ^ UNINTERESTING);
740                                 include = get_reference(revs, next, sha1, flags);
741                                 if (!exclude || !include)
742                                         die("Invalid revision range %s..%s", arg, next);
743                                 add_pending_object(revs, exclude, this);
744                                 add_pending_object(revs, include, next);
745                                 continue;
746                         }
747                         *dotdot = '.';
748                 }
749                 local_flags = 0;
750                 if (*arg == '^') {
751                         local_flags = UNINTERESTING;
752                         arg++;
753                 }
754                 if (get_sha1(arg, sha1) < 0) {
755                         struct stat st;
756                         int j;
757
758                         if (seen_dashdash || local_flags)
759                                 die("bad revision '%s'", arg);
760
761                         /* If we didn't have a "--", all filenames must exist */
762                         for (j = i; j < argc; j++) {
763                                 if (lstat(argv[j], &st) < 0)
764                                         die("'%s': %s", argv[j], strerror(errno));
765                         }
766                         revs->prune_data = get_pathspec(revs->prefix, argv + i);
767                         break;
768                 }
769                 object = get_reference(revs, arg, sha1, flags ^ local_flags);
770                 add_pending_object(revs, object, arg);
771         }
772         if (def && !revs->pending_objects) {
773                 unsigned char sha1[20];
774                 struct object *object;
775                 if (get_sha1(def, sha1) < 0)
776                         die("bad default revision '%s'", def);
777                 object = get_reference(revs, def, sha1, 0);
778                 add_pending_object(revs, object, def);
779         }
780
781         if (revs->topo_order || revs->unpacked)
782                 revs->limited = 1;
783
784         if (revs->prune_data) {
785                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
786                 revs->prune_fn = try_to_simplify_commit;
787                 if (!revs->full_diff)
788                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
789         }
790         if (revs->combine_merges) {
791                 revs->ignore_merges = 0;
792                 if (revs->dense_combined_merges)
793                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
794         }
795         revs->diffopt.abbrev = revs->abbrev;
796         diff_setup_done(&revs->diffopt);
797
798         return left;
799 }
800
801 void prepare_revision_walk(struct rev_info *revs)
802 {
803         struct object_list *list;
804
805         list = revs->pending_objects;
806         revs->pending_objects = NULL;
807         while (list) {
808                 struct commit *commit = handle_commit(revs, list->item, list->name);
809                 if (commit) {
810                         if (!(commit->object.flags & SEEN)) {
811                                 commit->object.flags |= SEEN;
812                                 insert_by_date(commit, &revs->commits);
813                         }
814                 }
815                 list = list->next;
816         }
817
818         if (revs->no_walk)
819                 return;
820         if (revs->limited)
821                 limit_list(revs);
822         if (revs->topo_order)
823                 sort_in_topological_order_fn(&revs->commits, revs->lifo,
824                                              revs->topo_setter,
825                                              revs->topo_getter);
826 }
827
828 static int rewrite_one(struct rev_info *revs, struct commit **pp)
829 {
830         for (;;) {
831                 struct commit *p = *pp;
832                 if (!revs->limited)
833                         add_parents_to_list(revs, p, &revs->commits);
834                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
835                         return 0;
836                 if (!p->parents)
837                         return -1;
838                 *pp = p->parents->item;
839         }
840 }
841
842 static void rewrite_parents(struct rev_info *revs, struct commit *commit)
843 {
844         struct commit_list **pp = &commit->parents;
845         while (*pp) {
846                 struct commit_list *parent = *pp;
847                 if (rewrite_one(revs, &parent->item) < 0) {
848                         *pp = parent->next;
849                         continue;
850                 }
851                 pp = &parent->next;
852         }
853 }
854
855 static void mark_boundary_to_show(struct commit *commit)
856 {
857         struct commit_list *p = commit->parents;
858         while (p) {
859                 commit = p->item;
860                 p = p->next;
861                 if (commit->object.flags & BOUNDARY)
862                         commit->object.flags |= BOUNDARY_SHOW;
863         }
864 }
865
866 struct commit *get_revision(struct rev_info *revs)
867 {
868         struct commit_list *list = revs->commits;
869
870         if (!list)
871                 return NULL;
872
873         /* Check the max_count ... */
874         switch (revs->max_count) {
875         case -1:
876                 break;
877         case 0:
878                 return NULL;
879         default:
880                 revs->max_count--;
881         }
882
883         do {
884                 struct commit *commit = revs->commits->item;
885
886                 revs->commits = revs->commits->next;
887
888                 /*
889                  * If we haven't done the list limiting, we need to look at
890                  * the parents here. We also need to do the date-based limiting
891                  * that we'd otherwise have done in limit_list().
892                  */
893                 if (!revs->limited) {
894                         if ((revs->unpacked &&
895                              has_sha1_pack(commit->object.sha1)) ||
896                             (revs->max_age != -1 &&
897                              (commit->date < revs->max_age)))
898                                 continue;
899                         add_parents_to_list(revs, commit, &revs->commits);
900                 }
901                 if (commit->object.flags & SHOWN)
902                         continue;
903
904                 /* We want to show boundary commits only when their
905                  * children are shown.  When path-limiter is in effect,
906                  * rewrite_parents() drops some commits from getting shown,
907                  * and there is no point showing boundary parents that
908                  * are not shown.  After rewrite_parents() rewrites the
909                  * parents of a commit that is shown, we mark the boundary
910                  * parents with BOUNDARY_SHOW.
911                  */
912                 if (commit->object.flags & BOUNDARY_SHOW) {
913                         commit->object.flags |= SHOWN;
914                         return commit;
915                 }
916                 if (commit->object.flags & UNINTERESTING)
917                         continue;
918                 if (revs->min_age != -1 && (commit->date > revs->min_age))
919                         continue;
920                 if (revs->no_merges &&
921                     commit->parents && commit->parents->next)
922                         continue;
923                 if (revs->prune_fn && revs->dense) {
924                         if (!(commit->object.flags & TREECHANGE))
925                                 continue;
926                         if (revs->parents)
927                                 rewrite_parents(revs, commit);
928                 }
929                 if (revs->boundary)
930                         mark_boundary_to_show(commit);
931                 commit->object.flags |= SHOWN;
932                 return commit;
933         } while (revs->commits);
934         return NULL;
935 }