Merge branch 'tr/maint-1.6.1-doc-format-patch--root'
[git] / builtin-rev-list.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "tag.h"
4 #include "commit.h"
5 #include "tree.h"
6 #include "blob.h"
7 #include "tree-walk.h"
8 #include "diff.h"
9 #include "revision.h"
10 #include "list-objects.h"
11 #include "builtin.h"
12 #include "log-tree.h"
13 #include "graph.h"
14
15 /* bits #0-15 in revision.h */
16
17 #define COUNTED         (1u<<16)
18
19 static const char rev_list_usage[] =
20 "git rev-list [OPTION] <commit-id>... [ -- paths... ]\n"
21 "  limiting output:\n"
22 "    --max-count=nr\n"
23 "    --max-age=epoch\n"
24 "    --min-age=epoch\n"
25 "    --sparse\n"
26 "    --no-merges\n"
27 "    --remove-empty\n"
28 "    --all\n"
29 "    --branches\n"
30 "    --tags\n"
31 "    --remotes\n"
32 "    --stdin\n"
33 "    --quiet\n"
34 "  ordering output:\n"
35 "    --topo-order\n"
36 "    --date-order\n"
37 "    --reverse\n"
38 "  formatting output:\n"
39 "    --parents\n"
40 "    --children\n"
41 "    --objects | --objects-edge\n"
42 "    --unpacked\n"
43 "    --header | --pretty\n"
44 "    --abbrev=nr | --no-abbrev\n"
45 "    --abbrev-commit\n"
46 "    --left-right\n"
47 "  special purpose:\n"
48 "    --bisect\n"
49 "    --bisect-vars\n"
50 "    --bisect-all"
51 ;
52
53 static struct rev_info revs;
54
55 static int bisect_list;
56 static int show_timestamp;
57 static int hdr_termination;
58 static const char *header_prefix;
59
60 static void finish_commit(struct commit *commit);
61 static void show_commit(struct commit *commit)
62 {
63         graph_show_commit(revs.graph);
64
65         if (show_timestamp)
66                 printf("%lu ", commit->date);
67         if (header_prefix)
68                 fputs(header_prefix, stdout);
69
70         if (!revs.graph) {
71                 if (commit->object.flags & BOUNDARY)
72                         putchar('-');
73                 else if (commit->object.flags & UNINTERESTING)
74                         putchar('^');
75                 else if (revs.left_right) {
76                         if (commit->object.flags & SYMMETRIC_LEFT)
77                                 putchar('<');
78                         else
79                                 putchar('>');
80                 }
81         }
82         if (revs.abbrev_commit && revs.abbrev)
83                 fputs(find_unique_abbrev(commit->object.sha1, revs.abbrev),
84                       stdout);
85         else
86                 fputs(sha1_to_hex(commit->object.sha1), stdout);
87         if (revs.print_parents) {
88                 struct commit_list *parents = commit->parents;
89                 while (parents) {
90                         printf(" %s", sha1_to_hex(parents->item->object.sha1));
91                         parents = parents->next;
92                 }
93         }
94         if (revs.children.name) {
95                 struct commit_list *children;
96
97                 children = lookup_decoration(&revs.children, &commit->object);
98                 while (children) {
99                         printf(" %s", sha1_to_hex(children->item->object.sha1));
100                         children = children->next;
101                 }
102         }
103         show_decorations(&revs, commit);
104         if (revs.commit_format == CMIT_FMT_ONELINE)
105                 putchar(' ');
106         else
107                 putchar('\n');
108
109         if (revs.verbose_header && commit->buffer) {
110                 struct strbuf buf = STRBUF_INIT;
111                 pretty_print_commit(revs.commit_format, commit,
112                                     &buf, revs.abbrev, NULL, NULL,
113                                     revs.date_mode, 0);
114                 if (revs.graph) {
115                         if (buf.len) {
116                                 if (revs.commit_format != CMIT_FMT_ONELINE)
117                                         graph_show_oneline(revs.graph);
118
119                                 graph_show_commit_msg(revs.graph, &buf);
120
121                                 /*
122                                  * Add a newline after the commit message.
123                                  *
124                                  * Usually, this newline produces a blank
125                                  * padding line between entries, in which case
126                                  * we need to add graph padding on this line.
127                                  *
128                                  * However, the commit message may not end in a
129                                  * newline.  In this case the newline simply
130                                  * ends the last line of the commit message,
131                                  * and we don't need any graph output.  (This
132                                  * always happens with CMIT_FMT_ONELINE, and it
133                                  * happens with CMIT_FMT_USERFORMAT when the
134                                  * format doesn't explicitly end in a newline.)
135                                  */
136                                 if (buf.len && buf.buf[buf.len - 1] == '\n')
137                                         graph_show_padding(revs.graph);
138                                 putchar('\n');
139                         } else {
140                                 /*
141                                  * If the message buffer is empty, just show
142                                  * the rest of the graph output for this
143                                  * commit.
144                                  */
145                                 if (graph_show_remainder(revs.graph))
146                                         putchar('\n');
147                         }
148                 } else {
149                         if (buf.len)
150                                 printf("%s%c", buf.buf, hdr_termination);
151                 }
152                 strbuf_release(&buf);
153         } else {
154                 if (graph_show_remainder(revs.graph))
155                         putchar('\n');
156         }
157         maybe_flush_or_die(stdout, "stdout");
158         finish_commit(commit);
159 }
160
161 static void finish_commit(struct commit *commit)
162 {
163         if (commit->parents) {
164                 free_commit_list(commit->parents);
165                 commit->parents = NULL;
166         }
167         free(commit->buffer);
168         commit->buffer = NULL;
169 }
170
171 static void finish_object(struct object_array_entry *p)
172 {
173         if (p->item->type == OBJ_BLOB && !has_sha1_file(p->item->sha1))
174                 die("missing blob object '%s'", sha1_to_hex(p->item->sha1));
175 }
176
177 static void show_object(struct object_array_entry *p)
178 {
179         /* An object with name "foo\n0000000..." can be used to
180          * confuse downstream "git pack-objects" very badly.
181          */
182         const char *ep = strchr(p->name, '\n');
183
184         finish_object(p);
185         if (ep) {
186                 printf("%s %.*s\n", sha1_to_hex(p->item->sha1),
187                        (int) (ep - p->name),
188                        p->name);
189         }
190         else
191                 printf("%s %s\n", sha1_to_hex(p->item->sha1), p->name);
192 }
193
194 static void show_edge(struct commit *commit)
195 {
196         printf("-%s\n", sha1_to_hex(commit->object.sha1));
197 }
198
199 /*
200  * This is a truly stupid algorithm, but it's only
201  * used for bisection, and we just don't care enough.
202  *
203  * We care just barely enough to avoid recursing for
204  * non-merge entries.
205  */
206 static int count_distance(struct commit_list *entry)
207 {
208         int nr = 0;
209
210         while (entry) {
211                 struct commit *commit = entry->item;
212                 struct commit_list *p;
213
214                 if (commit->object.flags & (UNINTERESTING | COUNTED))
215                         break;
216                 if (!(commit->object.flags & TREESAME))
217                         nr++;
218                 commit->object.flags |= COUNTED;
219                 p = commit->parents;
220                 entry = p;
221                 if (p) {
222                         p = p->next;
223                         while (p) {
224                                 nr += count_distance(p);
225                                 p = p->next;
226                         }
227                 }
228         }
229
230         return nr;
231 }
232
233 static void clear_distance(struct commit_list *list)
234 {
235         while (list) {
236                 struct commit *commit = list->item;
237                 commit->object.flags &= ~COUNTED;
238                 list = list->next;
239         }
240 }
241
242 #define DEBUG_BISECT 0
243
244 static inline int weight(struct commit_list *elem)
245 {
246         return *((int*)(elem->item->util));
247 }
248
249 static inline void weight_set(struct commit_list *elem, int weight)
250 {
251         *((int*)(elem->item->util)) = weight;
252 }
253
254 static int count_interesting_parents(struct commit *commit)
255 {
256         struct commit_list *p;
257         int count;
258
259         for (count = 0, p = commit->parents; p; p = p->next) {
260                 if (p->item->object.flags & UNINTERESTING)
261                         continue;
262                 count++;
263         }
264         return count;
265 }
266
267 static inline int halfway(struct commit_list *p, int nr)
268 {
269         /*
270          * Don't short-cut something we are not going to return!
271          */
272         if (p->item->object.flags & TREESAME)
273                 return 0;
274         if (DEBUG_BISECT)
275                 return 0;
276         /*
277          * 2 and 3 are halfway of 5.
278          * 3 is halfway of 6 but 2 and 4 are not.
279          */
280         switch (2 * weight(p) - nr) {
281         case -1: case 0: case 1:
282                 return 1;
283         default:
284                 return 0;
285         }
286 }
287
288 #if !DEBUG_BISECT
289 #define show_list(a,b,c,d) do { ; } while (0)
290 #else
291 static void show_list(const char *debug, int counted, int nr,
292                       struct commit_list *list)
293 {
294         struct commit_list *p;
295
296         fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
297
298         for (p = list; p; p = p->next) {
299                 struct commit_list *pp;
300                 struct commit *commit = p->item;
301                 unsigned flags = commit->object.flags;
302                 enum object_type type;
303                 unsigned long size;
304                 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
305                 char *ep, *sp;
306
307                 fprintf(stderr, "%c%c%c ",
308                         (flags & TREESAME) ? ' ' : 'T',
309                         (flags & UNINTERESTING) ? 'U' : ' ',
310                         (flags & COUNTED) ? 'C' : ' ');
311                 if (commit->util)
312                         fprintf(stderr, "%3d", weight(p));
313                 else
314                         fprintf(stderr, "---");
315                 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
316                 for (pp = commit->parents; pp; pp = pp->next)
317                         fprintf(stderr, " %.*s", 8,
318                                 sha1_to_hex(pp->item->object.sha1));
319
320                 sp = strstr(buf, "\n\n");
321                 if (sp) {
322                         sp += 2;
323                         for (ep = sp; *ep && *ep != '\n'; ep++)
324                                 ;
325                         fprintf(stderr, " %.*s", (int)(ep - sp), sp);
326                 }
327                 fprintf(stderr, "\n");
328         }
329 }
330 #endif /* DEBUG_BISECT */
331
332 static struct commit_list *best_bisection(struct commit_list *list, int nr)
333 {
334         struct commit_list *p, *best;
335         int best_distance = -1;
336
337         best = list;
338         for (p = list; p; p = p->next) {
339                 int distance;
340                 unsigned flags = p->item->object.flags;
341
342                 if (flags & TREESAME)
343                         continue;
344                 distance = weight(p);
345                 if (nr - distance < distance)
346                         distance = nr - distance;
347                 if (distance > best_distance) {
348                         best = p;
349                         best_distance = distance;
350                 }
351         }
352
353         return best;
354 }
355
356 struct commit_dist {
357         struct commit *commit;
358         int distance;
359 };
360
361 static int compare_commit_dist(const void *a_, const void *b_)
362 {
363         struct commit_dist *a, *b;
364
365         a = (struct commit_dist *)a_;
366         b = (struct commit_dist *)b_;
367         if (a->distance != b->distance)
368                 return b->distance - a->distance; /* desc sort */
369         return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
370 }
371
372 static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
373 {
374         struct commit_list *p;
375         struct commit_dist *array = xcalloc(nr, sizeof(*array));
376         int cnt, i;
377
378         for (p = list, cnt = 0; p; p = p->next) {
379                 int distance;
380                 unsigned flags = p->item->object.flags;
381
382                 if (flags & TREESAME)
383                         continue;
384                 distance = weight(p);
385                 if (nr - distance < distance)
386                         distance = nr - distance;
387                 array[cnt].commit = p->item;
388                 array[cnt].distance = distance;
389                 cnt++;
390         }
391         qsort(array, cnt, sizeof(*array), compare_commit_dist);
392         for (p = list, i = 0; i < cnt; i++) {
393                 struct name_decoration *r = xmalloc(sizeof(*r) + 100);
394                 struct object *obj = &(array[i].commit->object);
395
396                 sprintf(r->name, "dist=%d", array[i].distance);
397                 r->next = add_decoration(&name_decoration, obj, r);
398                 p->item = array[i].commit;
399                 p = p->next;
400         }
401         if (p)
402                 p->next = NULL;
403         free(array);
404         return list;
405 }
406
407 /*
408  * zero or positive weight is the number of interesting commits it can
409  * reach, including itself.  Especially, weight = 0 means it does not
410  * reach any tree-changing commits (e.g. just above uninteresting one
411  * but traversal is with pathspec).
412  *
413  * weight = -1 means it has one parent and its distance is yet to
414  * be computed.
415  *
416  * weight = -2 means it has more than one parent and its distance is
417  * unknown.  After running count_distance() first, they will get zero
418  * or positive distance.
419  */
420 static struct commit_list *do_find_bisection(struct commit_list *list,
421                                              int nr, int *weights,
422                                              int find_all)
423 {
424         int n, counted;
425         struct commit_list *p;
426
427         counted = 0;
428
429         for (n = 0, p = list; p; p = p->next) {
430                 struct commit *commit = p->item;
431                 unsigned flags = commit->object.flags;
432
433                 p->item->util = &weights[n++];
434                 switch (count_interesting_parents(commit)) {
435                 case 0:
436                         if (!(flags & TREESAME)) {
437                                 weight_set(p, 1);
438                                 counted++;
439                                 show_list("bisection 2 count one",
440                                           counted, nr, list);
441                         }
442                         /*
443                          * otherwise, it is known not to reach any
444                          * tree-changing commit and gets weight 0.
445                          */
446                         break;
447                 case 1:
448                         weight_set(p, -1);
449                         break;
450                 default:
451                         weight_set(p, -2);
452                         break;
453                 }
454         }
455
456         show_list("bisection 2 initialize", counted, nr, list);
457
458         /*
459          * If you have only one parent in the resulting set
460          * then you can reach one commit more than that parent
461          * can reach.  So we do not have to run the expensive
462          * count_distance() for single strand of pearls.
463          *
464          * However, if you have more than one parents, you cannot
465          * just add their distance and one for yourself, since
466          * they usually reach the same ancestor and you would
467          * end up counting them twice that way.
468          *
469          * So we will first count distance of merges the usual
470          * way, and then fill the blanks using cheaper algorithm.
471          */
472         for (p = list; p; p = p->next) {
473                 if (p->item->object.flags & UNINTERESTING)
474                         continue;
475                 if (weight(p) != -2)
476                         continue;
477                 weight_set(p, count_distance(p));
478                 clear_distance(list);
479
480                 /* Does it happen to be at exactly half-way? */
481                 if (!find_all && halfway(p, nr))
482                         return p;
483                 counted++;
484         }
485
486         show_list("bisection 2 count_distance", counted, nr, list);
487
488         while (counted < nr) {
489                 for (p = list; p; p = p->next) {
490                         struct commit_list *q;
491                         unsigned flags = p->item->object.flags;
492
493                         if (0 <= weight(p))
494                                 continue;
495                         for (q = p->item->parents; q; q = q->next) {
496                                 if (q->item->object.flags & UNINTERESTING)
497                                         continue;
498                                 if (0 <= weight(q))
499                                         break;
500                         }
501                         if (!q)
502                                 continue;
503
504                         /*
505                          * weight for p is unknown but q is known.
506                          * add one for p itself if p is to be counted,
507                          * otherwise inherit it from q directly.
508                          */
509                         if (!(flags & TREESAME)) {
510                                 weight_set(p, weight(q)+1);
511                                 counted++;
512                                 show_list("bisection 2 count one",
513                                           counted, nr, list);
514                         }
515                         else
516                                 weight_set(p, weight(q));
517
518                         /* Does it happen to be at exactly half-way? */
519                         if (!find_all && halfway(p, nr))
520                                 return p;
521                 }
522         }
523
524         show_list("bisection 2 counted all", counted, nr, list);
525
526         if (!find_all)
527                 return best_bisection(list, nr);
528         else
529                 return best_bisection_sorted(list, nr);
530 }
531
532 static struct commit_list *find_bisection(struct commit_list *list,
533                                           int *reaches, int *all,
534                                           int find_all)
535 {
536         int nr, on_list;
537         struct commit_list *p, *best, *next, *last;
538         int *weights;
539
540         show_list("bisection 2 entry", 0, 0, list);
541
542         /*
543          * Count the number of total and tree-changing items on the
544          * list, while reversing the list.
545          */
546         for (nr = on_list = 0, last = NULL, p = list;
547              p;
548              p = next) {
549                 unsigned flags = p->item->object.flags;
550
551                 next = p->next;
552                 if (flags & UNINTERESTING)
553                         continue;
554                 p->next = last;
555                 last = p;
556                 if (!(flags & TREESAME))
557                         nr++;
558                 on_list++;
559         }
560         list = last;
561         show_list("bisection 2 sorted", 0, nr, list);
562
563         *all = nr;
564         weights = xcalloc(on_list, sizeof(*weights));
565
566         /* Do the real work of finding bisection commit. */
567         best = do_find_bisection(list, nr, weights, find_all);
568         if (best) {
569                 if (!find_all)
570                         best->next = NULL;
571                 *reaches = weight(best);
572         }
573         free(weights);
574         return best;
575 }
576
577 static inline int log2i(int n)
578 {
579         int log2 = 0;
580
581         for (; n > 1; n >>= 1)
582                 log2++;
583
584         return log2;
585 }
586
587 static inline int exp2i(int n)
588 {
589         return 1 << n;
590 }
591
592 /*
593  * Estimate the number of bisect steps left (after the current step)
594  *
595  * For any x between 0 included and 2^n excluded, the probability for
596  * n - 1 steps left looks like:
597  *
598  * P(2^n + x) == (2^n - x) / (2^n + x)
599  *
600  * and P(2^n + x) < 0.5 means 2^n < 3x
601  */
602 static int estimate_bisect_steps(int all)
603 {
604         int n, x, e;
605
606         if (all < 3)
607                 return 0;
608
609         n = log2i(all);
610         e = exp2i(n);
611         x = all - e;
612
613         return (e < 3 * x) ? n : n - 1;
614 }
615
616 int cmd_rev_list(int argc, const char **argv, const char *prefix)
617 {
618         struct commit_list *list;
619         int i;
620         int read_from_stdin = 0;
621         int bisect_show_vars = 0;
622         int bisect_find_all = 0;
623         int quiet = 0;
624
625         git_config(git_default_config, NULL);
626         init_revisions(&revs, prefix);
627         revs.abbrev = 0;
628         revs.commit_format = CMIT_FMT_UNSPECIFIED;
629         argc = setup_revisions(argc, argv, &revs, NULL);
630
631         quiet = DIFF_OPT_TST(&revs.diffopt, QUIET);
632         for (i = 1 ; i < argc; i++) {
633                 const char *arg = argv[i];
634
635                 if (!strcmp(arg, "--header")) {
636                         revs.verbose_header = 1;
637                         continue;
638                 }
639                 if (!strcmp(arg, "--timestamp")) {
640                         show_timestamp = 1;
641                         continue;
642                 }
643                 if (!strcmp(arg, "--bisect")) {
644                         bisect_list = 1;
645                         continue;
646                 }
647                 if (!strcmp(arg, "--bisect-all")) {
648                         bisect_list = 1;
649                         bisect_find_all = 1;
650                         revs.show_decorations = 1;
651                         continue;
652                 }
653                 if (!strcmp(arg, "--bisect-vars")) {
654                         bisect_list = 1;
655                         bisect_show_vars = 1;
656                         continue;
657                 }
658                 if (!strcmp(arg, "--stdin")) {
659                         if (read_from_stdin++)
660                                 die("--stdin given twice?");
661                         read_revisions_from_stdin(&revs);
662                         continue;
663                 }
664                 usage(rev_list_usage);
665
666         }
667         if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {
668                 /* The command line has a --pretty  */
669                 hdr_termination = '\n';
670                 if (revs.commit_format == CMIT_FMT_ONELINE)
671                         header_prefix = "";
672                 else
673                         header_prefix = "commit ";
674         }
675         else if (revs.verbose_header)
676                 /* Only --header was specified */
677                 revs.commit_format = CMIT_FMT_RAW;
678
679         list = revs.commits;
680
681         if ((!list &&
682              (!(revs.tag_objects||revs.tree_objects||revs.blob_objects) &&
683               !revs.pending.nr)) ||
684             revs.diff)
685                 usage(rev_list_usage);
686
687         save_commit_buffer = revs.verbose_header ||
688                 revs.grep_filter.pattern_list;
689         if (bisect_list)
690                 revs.limited = 1;
691
692         if (prepare_revision_walk(&revs))
693                 die("revision walk setup failed");
694         if (revs.tree_objects)
695                 mark_edges_uninteresting(revs.commits, &revs, show_edge);
696
697         if (bisect_list) {
698                 int reaches = reaches, all = all;
699
700                 revs.commits = find_bisection(revs.commits, &reaches, &all,
701                                               bisect_find_all);
702                 if (bisect_show_vars) {
703                         int cnt;
704                         char hex[41];
705                         if (!revs.commits)
706                                 return 1;
707                         /*
708                          * revs.commits can reach "reaches" commits among
709                          * "all" commits.  If it is good, then there are
710                          * (all-reaches) commits left to be bisected.
711                          * On the other hand, if it is bad, then the set
712                          * to bisect is "reaches".
713                          * A bisect set of size N has (N-1) commits further
714                          * to test, as we already know one bad one.
715                          */
716                         cnt = all - reaches;
717                         if (cnt < reaches)
718                                 cnt = reaches;
719                         strcpy(hex, sha1_to_hex(revs.commits->item->object.sha1));
720
721                         if (bisect_find_all) {
722                                 traverse_commit_list(&revs, show_commit, show_object);
723                                 printf("------\n");
724                         }
725
726                         printf("bisect_rev=%s\n"
727                                "bisect_nr=%d\n"
728                                "bisect_good=%d\n"
729                                "bisect_bad=%d\n"
730                                "bisect_all=%d\n"
731                                "bisect_steps=%d\n",
732                                hex,
733                                cnt - 1,
734                                all - reaches - 1,
735                                reaches - 1,
736                                all,
737                                estimate_bisect_steps(all));
738                         return 0;
739                 }
740         }
741
742         traverse_commit_list(&revs,
743                 quiet ? finish_commit : show_commit,
744                 quiet ? finish_object : show_object);
745
746         return 0;
747 }