Rip out merge-order and make "git log <paths>..." work again.
[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                 commit->object.flags |= UNINTERESTING;
86
87                 /*
88                  * Normally we haven't parsed the parent
89                  * yet, so we won't have a parent of a parent
90                  * here. However, it may turn out that we've
91                  * reached this commit some other way (where it
92                  * wasn't uninteresting), in which case we need
93                  * to mark its parents recursively too..
94                  */
95                 if (commit->parents)
96                         mark_parents_uninteresting(commit);
97
98                 /*
99                  * A missing commit is ok iff its parent is marked
100                  * uninteresting.
101                  *
102                  * We just mark such a thing parsed, so that when
103                  * it is popped next time around, we won't be trying
104                  * to parse it and get an error.
105                  */
106                 if (!has_sha1_file(commit->object.sha1))
107                         commit->object.parsed = 1;
108                 parents = parents->next;
109         }
110 }
111
112 static void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
113 {
114         add_object(obj, &revs->pending_objects, NULL, name);
115 }
116
117 static struct commit *get_commit_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
118 {
119         struct object *object;
120
121         object = parse_object(sha1);
122         if (!object)
123                 die("bad object %s", name);
124
125         /*
126          * Tag object? Look what it points to..
127          */
128         while (object->type == tag_type) {
129                 struct tag *tag = (struct tag *) object;
130                 object->flags |= flags;
131                 if (revs->tag_objects && !(object->flags & UNINTERESTING))
132                         add_pending_object(revs, object, tag->tag);
133                 object = parse_object(tag->tagged->sha1);
134                 if (!object)
135                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
136         }
137
138         /*
139          * Commit object? Just return it, we'll do all the complex
140          * reachability crud.
141          */
142         if (object->type == commit_type) {
143                 struct commit *commit = (struct commit *)object;
144                 object->flags |= flags;
145                 if (parse_commit(commit) < 0)
146                         die("unable to parse commit %s", name);
147                 if (flags & UNINTERESTING) {
148                         mark_parents_uninteresting(commit);
149                         revs->limited = 1;
150                 }
151                 return commit;
152         }
153
154         /*
155          * Tree object? Either mark it uniniteresting, or add it
156          * to the list of objects to look at later..
157          */
158         if (object->type == tree_type) {
159                 struct tree *tree = (struct tree *)object;
160                 if (!revs->tree_objects)
161                         return NULL;
162                 if (flags & UNINTERESTING) {
163                         mark_tree_uninteresting(tree);
164                         return NULL;
165                 }
166                 add_pending_object(revs, object, "");
167                 return NULL;
168         }
169
170         /*
171          * Blob object? You know the drill by now..
172          */
173         if (object->type == blob_type) {
174                 struct blob *blob = (struct blob *)object;
175                 if (!revs->blob_objects)
176                         return NULL;
177                 if (flags & UNINTERESTING) {
178                         mark_blob_uninteresting(blob);
179                         return NULL;
180                 }
181                 add_pending_object(revs, object, "");
182                 return NULL;
183         }
184         die("%s is unknown object", name);
185 }
186
187 static int everybody_uninteresting(struct commit_list *orig)
188 {
189         struct commit_list *list = orig;
190         while (list) {
191                 struct commit *commit = list->item;
192                 list = list->next;
193                 if (commit->object.flags & UNINTERESTING)
194                         continue;
195                 return 0;
196         }
197         return 1;
198 }
199
200 #define TREE_SAME       0
201 #define TREE_NEW        1
202 #define TREE_DIFFERENT  2
203 static int tree_difference = TREE_SAME;
204
205 static void file_add_remove(struct diff_options *options,
206                     int addremove, unsigned mode,
207                     const unsigned char *sha1,
208                     const char *base, const char *path)
209 {
210         int diff = TREE_DIFFERENT;
211
212         /*
213          * Is it an add of a new file? It means that
214          * the old tree didn't have it at all, so we
215          * will turn "TREE_SAME" -> "TREE_NEW", but
216          * leave any "TREE_DIFFERENT" alone (and if
217          * it already was "TREE_NEW", we'll keep it
218          * "TREE_NEW" of course).
219          */
220         if (addremove == '+') {
221                 diff = tree_difference;
222                 if (diff != TREE_SAME)
223                         return;
224                 diff = TREE_NEW;
225         }
226         tree_difference = diff;
227 }
228
229 static void file_change(struct diff_options *options,
230                  unsigned old_mode, unsigned new_mode,
231                  const unsigned char *old_sha1,
232                  const unsigned char *new_sha1,
233                  const char *base, const char *path)
234 {
235         tree_difference = TREE_DIFFERENT;
236 }
237
238 static struct diff_options diff_opt = {
239         .recursive = 1,
240         .add_remove = file_add_remove,
241         .change = file_change,
242 };
243
244 static int compare_tree(struct tree *t1, struct tree *t2)
245 {
246         if (!t1)
247                 return TREE_NEW;
248         if (!t2)
249                 return TREE_DIFFERENT;
250         tree_difference = TREE_SAME;
251         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "", &diff_opt) < 0)
252                 return TREE_DIFFERENT;
253         return tree_difference;
254 }
255
256 static int same_tree_as_empty(struct tree *t1)
257 {
258         int retval;
259         void *tree;
260         struct tree_desc empty, real;
261
262         if (!t1)
263                 return 0;
264
265         tree = read_object_with_reference(t1->object.sha1, "tree", &real.size, NULL);
266         if (!tree)
267                 return 0;
268         real.buf = tree;
269
270         empty.buf = "";
271         empty.size = 0;
272
273         tree_difference = 0;
274         retval = diff_tree(&empty, &real, "", &diff_opt);
275         free(tree);
276
277         return retval >= 0 && !tree_difference;
278 }
279
280 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
281 {
282         struct commit_list **pp, *parent;
283
284         if (!commit->tree)
285                 return;
286
287         if (!commit->parents) {
288                 if (!same_tree_as_empty(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                 if (p->object.flags & UNINTERESTING) {
298                         pp = &parent->next;
299                         continue;
300                 }
301
302                 parse_commit(p);
303                 switch (compare_tree(p->tree, commit->tree)) {
304                 case TREE_SAME:
305                         parent->next = NULL;
306                         commit->parents = parent;
307                         return;
308
309                 case TREE_NEW:
310                         if (revs->remove_empty_trees && same_tree_as_empty(p->tree)) {
311                                 *pp = parent->next;
312                                 continue;
313                         }
314                 /* fallthrough */
315                 case TREE_DIFFERENT:
316                         pp = &parent->next;
317                         continue;
318                 }
319                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
320         }
321         commit->object.flags |= TREECHANGE;
322 }
323
324 static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
325 {
326         struct commit_list *parent = commit->parents;
327
328         /*
329          * If the commit is uninteresting, don't try to
330          * prune parents - we want the maximal uninteresting
331          * set.
332          *
333          * Normally we haven't parsed the parent
334          * yet, so we won't have a parent of a parent
335          * here. However, it may turn out that we've
336          * reached this commit some other way (where it
337          * wasn't uninteresting), in which case we need
338          * to mark its parents recursively too..
339          */
340         if (commit->object.flags & UNINTERESTING) {
341                 while (parent) {
342                         struct commit *p = parent->item;
343                         parent = parent->next;
344                         parse_commit(p);
345                         p->object.flags |= UNINTERESTING;
346                         if (p->parents)
347                                 mark_parents_uninteresting(p);
348                         if (p->object.flags & SEEN)
349                                 continue;
350                         p->object.flags |= SEEN;
351                         insert_by_date(p, list);
352                 }
353                 return;
354         }
355
356         /*
357          * Ok, the commit wasn't uninteresting. Try to
358          * simplify the commit history and find the parent
359          * that has no differences in the path set if one exists.
360          */
361         if (revs->paths)
362                 try_to_simplify_commit(revs, commit);
363
364         parent = commit->parents;
365         while (parent) {
366                 struct commit *p = parent->item;
367
368                 parent = parent->next;
369
370                 parse_commit(p);
371                 if (p->object.flags & SEEN)
372                         continue;
373                 p->object.flags |= SEEN;
374                 insert_by_date(p, list);
375         }
376 }
377
378 static void limit_list(struct rev_info *revs)
379 {
380         struct commit_list *list = revs->commits;
381         struct commit_list *newlist = NULL;
382         struct commit_list **p = &newlist;
383
384         if (revs->paths)
385                 diff_tree_setup_paths(revs->paths);
386
387         while (list) {
388                 struct commit_list *entry = list;
389                 struct commit *commit = list->item;
390                 struct object *obj = &commit->object;
391
392                 list = list->next;
393                 free(entry);
394
395                 if (revs->max_age != -1 && (commit->date < revs->max_age))
396                         obj->flags |= UNINTERESTING;
397                 if (revs->unpacked && has_sha1_pack(obj->sha1))
398                         obj->flags |= UNINTERESTING;
399                 add_parents_to_list(revs, commit, &list);
400                 if (obj->flags & UNINTERESTING) {
401                         mark_parents_uninteresting(commit);
402                         if (everybody_uninteresting(list))
403                                 break;
404                         continue;
405                 }
406                 if (revs->min_age != -1 && (commit->date > revs->min_age))
407                         continue;
408                 p = &commit_list_insert(commit, p)->next;
409         }
410         revs->commits = newlist;
411 }
412
413 static void add_one_commit(struct commit *commit, struct rev_info *revs)
414 {
415         if (!commit || (commit->object.flags & SEEN))
416                 return;
417         commit->object.flags |= SEEN;
418         commit_list_insert(commit, &revs->commits);
419 }
420
421 static int all_flags;
422 static struct rev_info *all_revs;
423
424 static int handle_one_ref(const char *path, const unsigned char *sha1)
425 {
426         struct commit *commit = get_commit_reference(all_revs, path, sha1, all_flags);
427         add_one_commit(commit, all_revs);
428         return 0;
429 }
430
431 static void handle_all(struct rev_info *revs, unsigned flags)
432 {
433         all_revs = revs;
434         all_flags = flags;
435         for_each_ref(handle_one_ref);
436 }
437
438 /*
439  * Parse revision information, filling in the "rev_info" structure,
440  * and removing the used arguments from the argument list.
441  *
442  * Returns the number of arguments left that weren't recognized
443  * (which are also moved to the head of the argument list)
444  */
445 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
446 {
447         int i, flags, seen_dashdash;
448         const char **unrecognized = argv + 1;
449         int left = 1;
450
451         memset(revs, 0, sizeof(*revs));
452         revs->lifo = 1;
453         revs->dense = 1;
454         revs->prefix = setup_git_directory();
455         revs->max_age = -1;
456         revs->min_age = -1;
457         revs->max_count = -1;
458
459         /* First, search for "--" */
460         seen_dashdash = 0;
461         for (i = 1; i < argc; i++) {
462                 const char *arg = argv[i];
463                 if (strcmp(arg, "--"))
464                         continue;
465                 argv[i] = NULL;
466                 argc = i;
467                 revs->paths = get_pathspec(revs->prefix, argv + i + 1);
468                 seen_dashdash = 1;
469                 break;
470         }
471
472         flags = 0;
473         for (i = 1; i < argc; i++) {
474                 struct commit *commit;
475                 const char *arg = argv[i];
476                 unsigned char sha1[20];
477                 char *dotdot;
478                 int local_flags;
479
480                 if (*arg == '-') {
481                         if (!strncmp(arg, "--max-count=", 12)) {
482                                 revs->max_count = atoi(arg + 12);
483                                 continue;
484                         }
485                         if (!strncmp(arg, "--max-age=", 10)) {
486                                 revs->max_age = atoi(arg + 10);
487                                 revs->limited = 1;
488                                 continue;
489                         }
490                         if (!strncmp(arg, "--min-age=", 10)) {
491                                 revs->min_age = atoi(arg + 10);
492                                 revs->limited = 1;
493                                 continue;
494                         }
495                         if (!strcmp(arg, "--all")) {
496                                 handle_all(revs, flags);
497                                 continue;
498                         }
499                         if (!strcmp(arg, "--not")) {
500                                 flags ^= UNINTERESTING;
501                                 continue;
502                         }
503                         if (!strcmp(arg, "--default")) {
504                                 if (++i >= argc)
505                                         die("bad --default argument");
506                                 def = argv[i];
507                                 continue;
508                         }
509                         if (!strcmp(arg, "--topo-order")) {
510                                 revs->topo_order = 1;
511                                 revs->limited = 1;
512                                 continue;
513                         }
514                         if (!strcmp(arg, "--date-order")) {
515                                 revs->lifo = 0;
516                                 revs->topo_order = 1;
517                                 revs->limited = 1;
518                                 continue;
519                         }
520                         if (!strcmp(arg, "--dense")) {
521                                 revs->dense = 1;
522                                 continue;
523                         }
524                         if (!strcmp(arg, "--sparse")) {
525                                 revs->dense = 0;
526                                 continue;
527                         }
528                         if (!strcmp(arg, "--remove-empty")) {
529                                 revs->remove_empty_trees = 1;
530                                 continue;
531                         }
532                         if (!strncmp(arg, "--no-merges", 11)) {
533                                 revs->no_merges = 1;
534                                 continue;
535                         }
536                         if (!strcmp(arg, "--objects")) {
537                                 revs->tag_objects = 1;
538                                 revs->tree_objects = 1;
539                                 revs->blob_objects = 1;
540                                 continue;
541                         }
542                         if (!strcmp(arg, "--objects-edge")) {
543                                 revs->tag_objects = 1;
544                                 revs->tree_objects = 1;
545                                 revs->blob_objects = 1;
546                                 revs->edge_hint = 1;
547                                 continue;
548                         }
549                         if (!strcmp(arg, "--unpacked")) {
550                                 revs->unpacked = 1;
551                                 revs->limited = 1;
552                                 continue;
553                         }
554                         *unrecognized++ = arg;
555                         left++;
556                         continue;
557                 }
558                 dotdot = strstr(arg, "..");
559                 if (dotdot) {
560                         unsigned char from_sha1[20];
561                         char *next = dotdot + 2;
562                         *dotdot = 0;
563                         if (!*next)
564                                 next = "HEAD";
565                         if (!get_sha1(arg, from_sha1) && !get_sha1(next, sha1)) {
566                                 struct commit *exclude;
567                                 struct commit *include;
568
569                                 exclude = get_commit_reference(revs, arg, from_sha1, flags ^ UNINTERESTING);
570                                 include = get_commit_reference(revs, next, sha1, flags);
571                                 if (!exclude || !include)
572                                         die("Invalid revision range %s..%s", arg, next);
573                                 add_one_commit(exclude, revs);
574                                 add_one_commit(include, revs);
575                                 continue;
576                         }
577                         *dotdot = '.';
578                 }
579                 local_flags = 0;
580                 if (*arg == '^') {
581                         local_flags = UNINTERESTING;
582                         arg++;
583                 }
584                 if (get_sha1(arg, sha1) < 0) {
585                         struct stat st;
586                         int j;
587
588                         if (seen_dashdash || local_flags)
589                                 die("bad revision '%s'", arg);
590
591                         /* If we didn't have a "--", all filenames must exist */
592                         for (j = i; j < argc; j++) {
593                                 if (lstat(argv[j], &st) < 0)
594                                         die("'%s': %s", arg, strerror(errno));
595                         }
596                         revs->paths = get_pathspec(revs->prefix, argv + i);
597                         break;
598                 }
599                 commit = get_commit_reference(revs, arg, sha1, flags ^ local_flags);
600                 add_one_commit(commit, revs);
601         }
602         if (def && !revs->commits) {
603                 unsigned char sha1[20];
604                 struct commit *commit;
605                 if (get_sha1(def, sha1) < 0)
606                         die("bad default revision '%s'", def);
607                 commit = get_commit_reference(revs, def, sha1, 0);
608                 add_one_commit(commit, revs);
609         }
610         if (revs->paths)
611                 revs->limited = 1;
612         return left;
613 }
614
615 void prepare_revision_walk(struct rev_info *revs)
616 {
617         sort_by_date(&revs->commits);
618         if (revs->limited)
619                 limit_list(revs);
620         if (revs->topo_order)
621                 sort_in_topological_order(&revs->commits, revs->lifo);
622 }
623
624 static int rewrite_one(struct commit **pp)
625 {
626         for (;;) {
627                 struct commit *p = *pp;
628                 if (p->object.flags & (TREECHANGE | UNINTERESTING))
629                         return 0;
630                 if (!p->parents)
631                         return -1;
632                 *pp = p->parents->item;
633         }
634 }
635
636 static void rewrite_parents(struct commit *commit)
637 {
638         struct commit_list **pp = &commit->parents;
639         while (*pp) {
640                 struct commit_list *parent = *pp;
641                 if (rewrite_one(&parent->item) < 0) {
642                         *pp = parent->next;
643                         continue;
644                 }
645                 pp = &parent->next;
646         }
647 }
648
649 struct commit *get_revision(struct rev_info *revs)
650 {
651         struct commit_list *list = revs->commits;
652         struct commit *commit;
653
654         if (!list)
655                 return NULL;
656
657         /* Check the max_count ... */
658         commit = list->item;
659         switch (revs->max_count) {
660         case -1:
661                 break;
662         case 0:
663                 return NULL;
664         default:
665                 revs->max_count--;
666         }
667
668         do {
669                 commit = pop_most_recent_commit(&revs->commits, SEEN);
670                 if (commit->object.flags & (UNINTERESTING|SHOWN))
671                         continue;
672                 if (revs->min_age != -1 && (commit->date > revs->min_age))
673                         continue;
674                 if (revs->max_age != -1 && (commit->date < revs->max_age))
675                         return NULL;
676                 if (revs->no_merges && commit->parents && commit->parents->next)
677                         continue;
678                 if (revs->paths && revs->dense) {
679                         if (!(commit->object.flags & TREECHANGE))
680                                 continue;
681                         rewrite_parents(commit);
682                 }
683                 commit->object.flags |= SHOWN;
684                 return commit;
685         } while (revs->commits);
686         return NULL;
687 }