Merge branch 'jc/empty' 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 commit *get_commit_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
127         /*
128          * Tag object? Look what it points to..
129          */
130         while (object->type == tag_type) {
131                 struct tag *tag = (struct tag *) object;
132                 object->flags |= flags;
133                 if (revs->tag_objects && !(object->flags & UNINTERESTING))
134                         add_pending_object(revs, object, tag->tag);
135                 object = parse_object(tag->tagged->sha1);
136                 if (!object)
137                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
138         }
139
140         /*
141          * Commit object? Just return it, we'll do all the complex
142          * reachability crud.
143          */
144         if (object->type == commit_type) {
145                 struct commit *commit = (struct commit *)object;
146                 object->flags |= flags;
147                 if (parse_commit(commit) < 0)
148                         die("unable to parse commit %s", name);
149                 if (flags & UNINTERESTING) {
150                         mark_parents_uninteresting(commit);
151                         revs->limited = 1;
152                 }
153                 return commit;
154         }
155
156         /*
157          * Tree object? Either mark it uniniteresting, or add it
158          * to the list of objects to look at later..
159          */
160         if (object->type == tree_type) {
161                 struct tree *tree = (struct tree *)object;
162                 if (!revs->tree_objects)
163                         return NULL;
164                 if (flags & UNINTERESTING) {
165                         mark_tree_uninteresting(tree);
166                         return NULL;
167                 }
168                 add_pending_object(revs, object, "");
169                 return NULL;
170         }
171
172         /*
173          * Blob object? You know the drill by now..
174          */
175         if (object->type == blob_type) {
176                 struct blob *blob = (struct blob *)object;
177                 if (!revs->blob_objects)
178                         return NULL;
179                 if (flags & UNINTERESTING) {
180                         mark_blob_uninteresting(blob);
181                         return NULL;
182                 }
183                 add_pending_object(revs, object, "");
184                 return NULL;
185         }
186         die("%s is unknown object", name);
187 }
188
189 static int everybody_uninteresting(struct commit_list *orig)
190 {
191         struct commit_list *list = orig;
192         while (list) {
193                 struct commit *commit = list->item;
194                 list = list->next;
195                 if (commit->object.flags & UNINTERESTING)
196                         continue;
197                 return 0;
198         }
199         return 1;
200 }
201
202 static int tree_difference = REV_TREE_SAME;
203
204 static void file_add_remove(struct diff_options *options,
205                     int addremove, unsigned mode,
206                     const unsigned char *sha1,
207                     const char *base, const char *path)
208 {
209         int diff = REV_TREE_DIFFERENT;
210
211         /*
212          * Is it an add of a new file? It means that the old tree
213          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
214          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
215          * (and if it already was "REV_TREE_NEW", we'll keep it
216          * "REV_TREE_NEW" of course).
217          */
218         if (addremove == '+') {
219                 diff = tree_difference;
220                 if (diff != REV_TREE_SAME)
221                         return;
222                 diff = REV_TREE_NEW;
223         }
224         tree_difference = diff;
225 }
226
227 static void file_change(struct diff_options *options,
228                  unsigned old_mode, unsigned new_mode,
229                  const unsigned char *old_sha1,
230                  const unsigned char *new_sha1,
231                  const char *base, const char *path)
232 {
233         tree_difference = REV_TREE_DIFFERENT;
234 }
235
236 static struct diff_options diff_opt = {
237         .recursive = 1,
238         .add_remove = file_add_remove,
239         .change = file_change,
240 };
241
242 int rev_compare_tree(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, "", &diff_opt) < 0)
250                 return REV_TREE_DIFFERENT;
251         return tree_difference;
252 }
253
254 int rev_same_tree_as_empty(struct tree *t1)
255 {
256         int retval;
257         void *tree;
258         struct tree_desc empty, real;
259
260         if (!t1)
261                 return 0;
262
263         tree = read_object_with_reference(t1->object.sha1, "tree", &real.size, NULL);
264         if (!tree)
265                 return 0;
266         real.buf = tree;
267
268         empty.buf = "";
269         empty.size = 0;
270
271         tree_difference = 0;
272         retval = diff_tree(&empty, &real, "", &diff_opt);
273         free(tree);
274
275         return retval >= 0 && !tree_difference;
276 }
277
278 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
279 {
280         struct commit_list **pp, *parent;
281         int tree_changed = 0;
282
283         if (!commit->tree)
284                 return;
285
286         if (!commit->parents) {
287                 if (!rev_same_tree_as_empty(commit->tree))
288                         commit->object.flags |= TREECHANGE;
289                 return;
290         }
291
292         pp = &commit->parents;
293         while ((parent = *pp) != NULL) {
294                 struct commit *p = parent->item;
295
296                 parse_commit(p);
297                 switch (rev_compare_tree(p->tree, commit->tree)) {
298                 case REV_TREE_SAME:
299                         if (p->object.flags & UNINTERESTING) {
300                                 /* Even if a merge with an uninteresting
301                                  * side branch brought the entire change
302                                  * we are interested in, we do not want
303                                  * to lose the other branches of this
304                                  * merge, so we just keep going.
305                                  */
306                                 pp = &parent->next;
307                                 continue;
308                         }
309                         parent->next = NULL;
310                         commit->parents = parent;
311                         return;
312
313                 case REV_TREE_NEW:
314                         if (revs->remove_empty_trees &&
315                             rev_same_tree_as_empty(p->tree)) {
316                                 /* We are adding all the specified paths from
317                                  * this parent, so the parents of it is
318                                  * not interesting, but the difference between
319                                  * this parent and us still is interesting.
320                                  */
321                                 p->object.flags |= UNINTERESTING;
322                         }
323                 /* fallthrough */
324                 case REV_TREE_DIFFERENT:
325                         tree_changed = 1;
326                         pp = &parent->next;
327                         continue;
328                 }
329                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
330         }
331         if (tree_changed)
332                 commit->object.flags |= TREECHANGE;
333 }
334
335 static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
336 {
337         struct commit_list *parent = commit->parents;
338
339         /*
340          * If the commit is uninteresting, don't try to
341          * prune parents - we want the maximal uninteresting
342          * set.
343          *
344          * Normally we haven't parsed the parent
345          * yet, so we won't have a parent of a parent
346          * here. However, it may turn out that we've
347          * reached this commit some other way (where it
348          * wasn't uninteresting), in which case we need
349          * to mark its parents recursively too..
350          */
351         if (commit->object.flags & UNINTERESTING) {
352                 while (parent) {
353                         struct commit *p = parent->item;
354                         parent = parent->next;
355                         parse_commit(p);
356                         p->object.flags |= UNINTERESTING;
357                         if (p->parents)
358                                 mark_parents_uninteresting(p);
359                         if (p->object.flags & SEEN)
360                                 continue;
361                         p->object.flags |= SEEN;
362                         insert_by_date(p, list);
363                 }
364                 return;
365         }
366
367         /*
368          * Ok, the commit wasn't uninteresting. Try to
369          * simplify the commit history and find the parent
370          * that has no differences in the path set if one exists.
371          */
372         if (revs->prune_fn)
373                 revs->prune_fn(revs, commit);
374
375         parent = commit->parents;
376         while (parent) {
377                 struct commit *p = parent->item;
378
379                 parent = parent->next;
380
381                 parse_commit(p);
382                 if (p->object.flags & SEEN)
383                         continue;
384                 p->object.flags |= SEEN;
385                 insert_by_date(p, list);
386         }
387 }
388
389 static void limit_list(struct rev_info *revs)
390 {
391         struct commit_list *list = revs->commits;
392         struct commit_list *newlist = NULL;
393         struct commit_list **p = &newlist;
394
395         while (list) {
396                 struct commit_list *entry = list;
397                 struct commit *commit = list->item;
398                 struct object *obj = &commit->object;
399
400                 list = list->next;
401                 free(entry);
402
403                 if (revs->max_age != -1 && (commit->date < revs->max_age))
404                         obj->flags |= UNINTERESTING;
405                 if (revs->unpacked && has_sha1_pack(obj->sha1))
406                         obj->flags |= UNINTERESTING;
407                 add_parents_to_list(revs, commit, &list);
408                 if (obj->flags & UNINTERESTING) {
409                         mark_parents_uninteresting(commit);
410                         if (everybody_uninteresting(list))
411                                 break;
412                         continue;
413                 }
414                 if (revs->min_age != -1 && (commit->date > revs->min_age))
415                         continue;
416                 p = &commit_list_insert(commit, p)->next;
417         }
418         revs->commits = newlist;
419 }
420
421 static void add_one_commit(struct commit *commit, struct rev_info *revs)
422 {
423         if (!commit || (commit->object.flags & SEEN))
424                 return;
425         commit->object.flags |= SEEN;
426         commit_list_insert(commit, &revs->commits);
427 }
428
429 static int all_flags;
430 static struct rev_info *all_revs;
431
432 static int handle_one_ref(const char *path, const unsigned char *sha1)
433 {
434         struct commit *commit = get_commit_reference(all_revs, path, sha1, all_flags);
435         add_one_commit(commit, all_revs);
436         return 0;
437 }
438
439 static void handle_all(struct rev_info *revs, unsigned flags)
440 {
441         all_revs = revs;
442         all_flags = flags;
443         for_each_ref(handle_one_ref);
444 }
445
446 void init_revisions(struct rev_info *revs)
447 {
448         memset(revs, 0, sizeof(*revs));
449         revs->lifo = 1;
450         revs->dense = 1;
451         revs->prefix = setup_git_directory();
452         revs->max_age = -1;
453         revs->min_age = -1;
454         revs->max_count = -1;
455
456         revs->prune_fn = NULL;
457         revs->prune_data = NULL;
458
459         revs->topo_setter = topo_sort_default_setter;
460         revs->topo_getter = topo_sort_default_getter;
461 }
462
463 /*
464  * Parse revision information, filling in the "rev_info" structure,
465  * and removing the used arguments from the argument list.
466  *
467  * Returns the number of arguments left that weren't recognized
468  * (which are also moved to the head of the argument list)
469  */
470 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
471 {
472         int i, flags, seen_dashdash;
473         const char **unrecognized = argv + 1;
474         int left = 1;
475
476         init_revisions(revs);
477
478         /* First, search for "--" */
479         seen_dashdash = 0;
480         for (i = 1; i < argc; i++) {
481                 const char *arg = argv[i];
482                 if (strcmp(arg, "--"))
483                         continue;
484                 argv[i] = NULL;
485                 argc = i;
486                 revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
487                 seen_dashdash = 1;
488                 break;
489         }
490
491         flags = 0;
492         for (i = 1; i < argc; i++) {
493                 struct commit *commit;
494                 const char *arg = argv[i];
495                 unsigned char sha1[20];
496                 char *dotdot;
497                 int local_flags;
498
499                 if (*arg == '-') {
500                         if (!strncmp(arg, "--max-count=", 12)) {
501                                 revs->max_count = atoi(arg + 12);
502                                 continue;
503                         }
504                         /* accept -<digit>, like traditilnal "head" */
505                         if ((*arg == '-') && isdigit(arg[1])) {
506                                 revs->max_count = atoi(arg + 1);
507                                 continue;
508                         }
509                         if (!strcmp(arg, "-n")) {
510                                 if (argc <= i + 1)
511                                         die("-n requires an argument");
512                                 revs->max_count = atoi(argv[++i]);
513                                 continue;
514                         }
515                         if (!strncmp(arg,"-n",2)) {
516                                 revs->max_count = atoi(arg + 2);
517                                 continue;
518                         }
519                         if (!strncmp(arg, "--max-age=", 10)) {
520                                 revs->max_age = atoi(arg + 10);
521                                 revs->limited = 1;
522                                 continue;
523                         }
524                         if (!strncmp(arg, "--min-age=", 10)) {
525                                 revs->min_age = atoi(arg + 10);
526                                 revs->limited = 1;
527                                 continue;
528                         }
529                         if (!strncmp(arg, "--since=", 8)) {
530                                 revs->max_age = approxidate(arg + 8);
531                                 revs->limited = 1;
532                                 continue;
533                         }
534                         if (!strncmp(arg, "--after=", 8)) {
535                                 revs->max_age = approxidate(arg + 8);
536                                 revs->limited = 1;
537                                 continue;
538                         }
539                         if (!strncmp(arg, "--before=", 9)) {
540                                 revs->min_age = approxidate(arg + 9);
541                                 revs->limited = 1;
542                                 continue;
543                         }
544                         if (!strncmp(arg, "--until=", 8)) {
545                                 revs->min_age = approxidate(arg + 8);
546                                 revs->limited = 1;
547                                 continue;
548                         }
549                         if (!strcmp(arg, "--all")) {
550                                 handle_all(revs, flags);
551                                 continue;
552                         }
553                         if (!strcmp(arg, "--not")) {
554                                 flags ^= UNINTERESTING;
555                                 continue;
556                         }
557                         if (!strcmp(arg, "--default")) {
558                                 if (++i >= argc)
559                                         die("bad --default argument");
560                                 def = argv[i];
561                                 continue;
562                         }
563                         if (!strcmp(arg, "--topo-order")) {
564                                 revs->topo_order = 1;
565                                 revs->limited = 1;
566                                 continue;
567                         }
568                         if (!strcmp(arg, "--date-order")) {
569                                 revs->lifo = 0;
570                                 revs->topo_order = 1;
571                                 revs->limited = 1;
572                                 continue;
573                         }
574                         if (!strcmp(arg, "--dense")) {
575                                 revs->dense = 1;
576                                 continue;
577                         }
578                         if (!strcmp(arg, "--sparse")) {
579                                 revs->dense = 0;
580                                 continue;
581                         }
582                         if (!strcmp(arg, "--remove-empty")) {
583                                 revs->remove_empty_trees = 1;
584                                 continue;
585                         }
586                         if (!strncmp(arg, "--no-merges", 11)) {
587                                 revs->no_merges = 1;
588                                 continue;
589                         }
590                         if (!strcmp(arg, "--objects")) {
591                                 revs->tag_objects = 1;
592                                 revs->tree_objects = 1;
593                                 revs->blob_objects = 1;
594                                 continue;
595                         }
596                         if (!strcmp(arg, "--objects-edge")) {
597                                 revs->tag_objects = 1;
598                                 revs->tree_objects = 1;
599                                 revs->blob_objects = 1;
600                                 revs->edge_hint = 1;
601                                 continue;
602                         }
603                         if (!strcmp(arg, "--unpacked")) {
604                                 revs->unpacked = 1;
605                                 revs->limited = 1;
606                                 continue;
607                         }
608                         *unrecognized++ = arg;
609                         left++;
610                         continue;
611                 }
612                 dotdot = strstr(arg, "..");
613                 if (dotdot) {
614                         unsigned char from_sha1[20];
615                         char *next = dotdot + 2;
616                         *dotdot = 0;
617                         if (!*next)
618                                 next = "HEAD";
619                         if (!get_sha1(arg, from_sha1) && !get_sha1(next, sha1)) {
620                                 struct commit *exclude;
621                                 struct commit *include;
622
623                                 exclude = get_commit_reference(revs, arg, from_sha1, flags ^ UNINTERESTING);
624                                 include = get_commit_reference(revs, next, sha1, flags);
625                                 if (!exclude || !include)
626                                         die("Invalid revision range %s..%s", arg, next);
627                                 add_one_commit(exclude, revs);
628                                 add_one_commit(include, revs);
629                                 continue;
630                         }
631                         *dotdot = '.';
632                 }
633                 local_flags = 0;
634                 if (*arg == '^') {
635                         local_flags = UNINTERESTING;
636                         arg++;
637                 }
638                 if (get_sha1(arg, sha1) < 0) {
639                         struct stat st;
640                         int j;
641
642                         if (seen_dashdash || local_flags)
643                                 die("bad revision '%s'", arg);
644
645                         /* If we didn't have a "--", all filenames must exist */
646                         for (j = i; j < argc; j++) {
647                                 if (lstat(argv[j], &st) < 0)
648                                         die("'%s': %s", arg, strerror(errno));
649                         }
650                         revs->prune_data = get_pathspec(revs->prefix, argv + i);
651                         break;
652                 }
653                 commit = get_commit_reference(revs, arg, sha1, flags ^ local_flags);
654                 add_one_commit(commit, revs);
655         }
656         if (def && !revs->commits) {
657                 unsigned char sha1[20];
658                 struct commit *commit;
659                 if (get_sha1(def, sha1) < 0)
660                         die("bad default revision '%s'", def);
661                 commit = get_commit_reference(revs, def, sha1, 0);
662                 add_one_commit(commit, revs);
663         }
664
665         if (revs->prune_data) {
666                 diff_tree_setup_paths(revs->prune_data);
667                 revs->prune_fn = try_to_simplify_commit;
668                 revs->limited = 1;
669         }
670
671         return left;
672 }
673
674 void prepare_revision_walk(struct rev_info *revs)
675 {
676         sort_by_date(&revs->commits);
677         if (revs->limited)
678                 limit_list(revs);
679         if (revs->topo_order)
680                 sort_in_topological_order_fn(&revs->commits, revs->lifo,
681                                              revs->topo_setter,
682                                              revs->topo_getter);
683 }
684
685 static int rewrite_one(struct commit **pp)
686 {
687         for (;;) {
688                 struct commit *p = *pp;
689                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
690                         return 0;
691                 if (!p->parents)
692                         return -1;
693                 *pp = p->parents->item;
694         }
695 }
696
697 static void rewrite_parents(struct commit *commit)
698 {
699         struct commit_list **pp = &commit->parents;
700         while (*pp) {
701                 struct commit_list *parent = *pp;
702                 if (rewrite_one(&parent->item) < 0) {
703                         *pp = parent->next;
704                         continue;
705                 }
706                 pp = &parent->next;
707         }
708 }
709
710 struct commit *get_revision(struct rev_info *revs)
711 {
712         struct commit_list *list = revs->commits;
713
714         if (!list)
715                 return NULL;
716
717         /* Check the max_count ... */
718         switch (revs->max_count) {
719         case -1:
720                 break;
721         case 0:
722                 return NULL;
723         default:
724                 revs->max_count--;
725         }
726
727         do {
728                 struct commit *commit = revs->commits->item;
729
730                 if (commit->object.flags & (UNINTERESTING|SHOWN))
731                         goto next;
732                 if (revs->min_age != -1 && (commit->date > revs->min_age))
733                         goto next;
734                 if (revs->max_age != -1 && (commit->date < revs->max_age))
735                         return NULL;
736                 if (revs->no_merges && commit->parents && commit->parents->next)
737                         goto next;
738                 if (revs->prune_fn && revs->dense) {
739                         if (!(commit->object.flags & TREECHANGE))
740                                 goto next;
741                         rewrite_parents(commit);
742                 }
743                 /* More to go? */
744                 if (revs->max_count)
745                         pop_most_recent_commit(&revs->commits, SEEN);
746                 commit->object.flags |= SHOWN;
747                 return commit;
748 next:
749                 pop_most_recent_commit(&revs->commits, SEEN);
750         } while (revs->commits);
751         return NULL;
752 }