Merge branch 'maint'
[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
13 /* bits #0-15 in revision.h */
14
15 #define COUNTED         (1u<<16)
16
17 static const char rev_list_usage[] =
18 "git-rev-list [OPTION] <commit-id>... [ -- paths... ]\n"
19 "  limiting output:\n"
20 "    --max-count=nr\n"
21 "    --max-age=epoch\n"
22 "    --min-age=epoch\n"
23 "    --sparse\n"
24 "    --no-merges\n"
25 "    --remove-empty\n"
26 "    --all\n"
27 "    --stdin\n"
28 "  ordering output:\n"
29 "    --topo-order\n"
30 "    --date-order\n"
31 "  formatting output:\n"
32 "    --parents\n"
33 "    --objects | --objects-edge\n"
34 "    --unpacked\n"
35 "    --header | --pretty\n"
36 "    --abbrev=nr | --no-abbrev\n"
37 "    --abbrev-commit\n"
38 "    --left-right\n"
39 "  special purpose:\n"
40 "    --bisect\n"
41 "    --bisect-vars"
42 ;
43
44 static struct rev_info revs;
45
46 static int bisect_list;
47 static int show_timestamp;
48 static int hdr_termination;
49 static const char *header_prefix;
50
51 static void show_commit(struct commit *commit)
52 {
53         if (show_timestamp)
54                 printf("%lu ", commit->date);
55         if (header_prefix)
56                 fputs(header_prefix, stdout);
57         if (commit->object.flags & BOUNDARY)
58                 putchar('-');
59         else if (revs.left_right) {
60                 if (commit->object.flags & SYMMETRIC_LEFT)
61                         putchar('<');
62                 else
63                         putchar('>');
64         }
65         if (revs.abbrev_commit && revs.abbrev)
66                 fputs(find_unique_abbrev(commit->object.sha1, revs.abbrev),
67                       stdout);
68         else
69                 fputs(sha1_to_hex(commit->object.sha1), stdout);
70         if (revs.parents) {
71                 struct commit_list *parents = commit->parents;
72                 while (parents) {
73                         printf(" %s", sha1_to_hex(parents->item->object.sha1));
74                         parents = parents->next;
75                 }
76         }
77         if (revs.commit_format == CMIT_FMT_ONELINE)
78                 putchar(' ');
79         else
80                 putchar('\n');
81
82         if (revs.verbose_header) {
83                 char *buf = NULL;
84                 unsigned long buflen = 0;
85                 pretty_print_commit(revs.commit_format, commit, ~0,
86                                     &buf, &buflen,
87                                     revs.abbrev, NULL, NULL, revs.date_mode);
88                 printf("%s%c", buf, hdr_termination);
89                 free(buf);
90         }
91         maybe_flush_or_die(stdout, "stdout");
92         if (commit->parents) {
93                 free_commit_list(commit->parents);
94                 commit->parents = NULL;
95         }
96         free(commit->buffer);
97         commit->buffer = NULL;
98 }
99
100 static void show_object(struct object_array_entry *p)
101 {
102         /* An object with name "foo\n0000000..." can be used to
103          * confuse downstream git-pack-objects very badly.
104          */
105         const char *ep = strchr(p->name, '\n');
106
107         if (p->item->type == OBJ_BLOB && !has_sha1_file(p->item->sha1))
108                 die("missing blob object '%s'", sha1_to_hex(p->item->sha1));
109
110         if (ep) {
111                 printf("%s %.*s\n", sha1_to_hex(p->item->sha1),
112                        (int) (ep - p->name),
113                        p->name);
114         }
115         else
116                 printf("%s %s\n", sha1_to_hex(p->item->sha1), p->name);
117 }
118
119 static void show_edge(struct commit *commit)
120 {
121         printf("-%s\n", sha1_to_hex(commit->object.sha1));
122 }
123
124 /*
125  * This is a truly stupid algorithm, but it's only
126  * used for bisection, and we just don't care enough.
127  *
128  * We care just barely enough to avoid recursing for
129  * non-merge entries.
130  */
131 static int count_distance(struct commit_list *entry)
132 {
133         int nr = 0;
134
135         while (entry) {
136                 struct commit *commit = entry->item;
137                 struct commit_list *p;
138
139                 if (commit->object.flags & (UNINTERESTING | COUNTED))
140                         break;
141                 if (!revs.prune_fn || (commit->object.flags & TREECHANGE))
142                         nr++;
143                 commit->object.flags |= COUNTED;
144                 p = commit->parents;
145                 entry = p;
146                 if (p) {
147                         p = p->next;
148                         while (p) {
149                                 nr += count_distance(p);
150                                 p = p->next;
151                         }
152                 }
153         }
154
155         return nr;
156 }
157
158 static void clear_distance(struct commit_list *list)
159 {
160         while (list) {
161                 struct commit *commit = list->item;
162                 commit->object.flags &= ~COUNTED;
163                 list = list->next;
164         }
165 }
166
167 #define DEBUG_BISECT 0
168
169 static inline int weight(struct commit_list *elem)
170 {
171         return *((int*)(elem->item->util));
172 }
173
174 static inline void weight_set(struct commit_list *elem, int weight)
175 {
176         *((int*)(elem->item->util)) = weight;
177 }
178
179 static int count_interesting_parents(struct commit *commit)
180 {
181         struct commit_list *p;
182         int count;
183
184         for (count = 0, p = commit->parents; p; p = p->next) {
185                 if (p->item->object.flags & UNINTERESTING)
186                         continue;
187                 count++;
188         }
189         return count;
190 }
191
192 static inline int halfway(struct commit_list *p, int nr)
193 {
194         /*
195          * Don't short-cut something we are not going to return!
196          */
197         if (revs.prune_fn && !(p->item->object.flags & TREECHANGE))
198                 return 0;
199         if (DEBUG_BISECT)
200                 return 0;
201         /*
202          * 2 and 3 are halfway of 5.
203          * 3 is halfway of 6 but 2 and 4 are not.
204          */
205         switch (2 * weight(p) - nr) {
206         case -1: case 0: case 1:
207                 return 1;
208         default:
209                 return 0;
210         }
211 }
212
213 #if !DEBUG_BISECT
214 #define show_list(a,b,c,d) do { ; } while (0)
215 #else
216 static void show_list(const char *debug, int counted, int nr,
217                       struct commit_list *list)
218 {
219         struct commit_list *p;
220
221         fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
222
223         for (p = list; p; p = p->next) {
224                 struct commit_list *pp;
225                 struct commit *commit = p->item;
226                 unsigned flags = commit->object.flags;
227                 enum object_type type;
228                 unsigned long size;
229                 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
230                 char *ep, *sp;
231
232                 fprintf(stderr, "%c%c%c ",
233                         (flags & TREECHANGE) ? 'T' : ' ',
234                         (flags & UNINTERESTING) ? 'U' : ' ',
235                         (flags & COUNTED) ? 'C' : ' ');
236                 if (commit->util)
237                         fprintf(stderr, "%3d", weight(p));
238                 else
239                         fprintf(stderr, "---");
240                 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
241                 for (pp = commit->parents; pp; pp = pp->next)
242                         fprintf(stderr, " %.*s", 8,
243                                 sha1_to_hex(pp->item->object.sha1));
244
245                 sp = strstr(buf, "\n\n");
246                 if (sp) {
247                         sp += 2;
248                         for (ep = sp; *ep && *ep != '\n'; ep++)
249                                 ;
250                         fprintf(stderr, " %.*s", (int)(ep - sp), sp);
251                 }
252                 fprintf(stderr, "\n");
253         }
254 }
255 #endif /* DEBUG_BISECT */
256
257 static struct commit_list *best_bisection(struct commit_list *list, int nr)
258 {
259         struct commit_list *p, *best;
260         int best_distance = -1;
261
262         best = list;
263         for (p = list; p; p = p->next) {
264                 int distance;
265                 unsigned flags = p->item->object.flags;
266
267                 if (revs.prune_fn && !(flags & TREECHANGE))
268                         continue;
269                 distance = weight(p);
270                 if (nr - distance < distance)
271                         distance = nr - distance;
272                 if (distance > best_distance) {
273                         best = p;
274                         best_distance = distance;
275                 }
276         }
277
278         return best;
279 }
280
281 /*
282  * zero or positive weight is the number of interesting commits it can
283  * reach, including itself.  Especially, weight = 0 means it does not
284  * reach any tree-changing commits (e.g. just above uninteresting one
285  * but traversal is with pathspec).
286  *
287  * weight = -1 means it has one parent and its distance is yet to
288  * be computed.
289  *
290  * weight = -2 means it has more than one parent and its distance is
291  * unknown.  After running count_distance() first, they will get zero
292  * or positive distance.
293  */
294 static struct commit_list *do_find_bisection(struct commit_list *list,
295                                              int nr, int *weights)
296 {
297         int n, counted;
298         struct commit_list *p;
299
300         counted = 0;
301
302         for (n = 0, p = list; p; p = p->next) {
303                 struct commit *commit = p->item;
304                 unsigned flags = commit->object.flags;
305
306                 p->item->util = &weights[n++];
307                 switch (count_interesting_parents(commit)) {
308                 case 0:
309                         if (!revs.prune_fn || (flags & TREECHANGE)) {
310                                 weight_set(p, 1);
311                                 counted++;
312                                 show_list("bisection 2 count one",
313                                           counted, nr, list);
314                         }
315                         /*
316                          * otherwise, it is known not to reach any
317                          * tree-changing commit and gets weight 0.
318                          */
319                         break;
320                 case 1:
321                         weight_set(p, -1);
322                         break;
323                 default:
324                         weight_set(p, -2);
325                         break;
326                 }
327         }
328
329         show_list("bisection 2 initialize", counted, nr, list);
330
331         /*
332          * If you have only one parent in the resulting set
333          * then you can reach one commit more than that parent
334          * can reach.  So we do not have to run the expensive
335          * count_distance() for single strand of pearls.
336          *
337          * However, if you have more than one parents, you cannot
338          * just add their distance and one for yourself, since
339          * they usually reach the same ancestor and you would
340          * end up counting them twice that way.
341          *
342          * So we will first count distance of merges the usual
343          * way, and then fill the blanks using cheaper algorithm.
344          */
345         for (p = list; p; p = p->next) {
346                 if (p->item->object.flags & UNINTERESTING)
347                         continue;
348                 if (weight(p) != -2)
349                         continue;
350                 weight_set(p, count_distance(p));
351                 clear_distance(list);
352
353                 /* Does it happen to be at exactly half-way? */
354                 if (halfway(p, nr))
355                         return p;
356                 counted++;
357         }
358
359         show_list("bisection 2 count_distance", counted, nr, list);
360
361         while (counted < nr) {
362                 for (p = list; p; p = p->next) {
363                         struct commit_list *q;
364                         unsigned flags = p->item->object.flags;
365
366                         if (0 <= weight(p))
367                                 continue;
368                         for (q = p->item->parents; q; q = q->next) {
369                                 if (q->item->object.flags & UNINTERESTING)
370                                         continue;
371                                 if (0 <= weight(q))
372                                         break;
373                         }
374                         if (!q)
375                                 continue;
376
377                         /*
378                          * weight for p is unknown but q is known.
379                          * add one for p itself if p is to be counted,
380                          * otherwise inherit it from q directly.
381                          */
382                         if (!revs.prune_fn || (flags & TREECHANGE)) {
383                                 weight_set(p, weight(q)+1);
384                                 counted++;
385                                 show_list("bisection 2 count one",
386                                           counted, nr, list);
387                         }
388                         else
389                                 weight_set(p, weight(q));
390
391                         /* Does it happen to be at exactly half-way? */
392                         if (halfway(p, nr))
393                                 return p;
394                 }
395         }
396
397         show_list("bisection 2 counted all", counted, nr, list);
398
399         /* Then find the best one */
400         return best_bisection(list, nr);
401 }
402
403 static struct commit_list *find_bisection(struct commit_list *list,
404                                           int *reaches, int *all)
405 {
406         int nr, on_list;
407         struct commit_list *p, *best, *next, *last;
408         int *weights;
409
410         show_list("bisection 2 entry", 0, 0, list);
411
412         /*
413          * Count the number of total and tree-changing items on the
414          * list, while reversing the list.
415          */
416         for (nr = on_list = 0, last = NULL, p = list;
417              p;
418              p = next) {
419                 unsigned flags = p->item->object.flags;
420
421                 next = p->next;
422                 if (flags & UNINTERESTING)
423                         continue;
424                 p->next = last;
425                 last = p;
426                 if (!revs.prune_fn || (flags & TREECHANGE))
427                         nr++;
428                 on_list++;
429         }
430         list = last;
431         show_list("bisection 2 sorted", 0, nr, list);
432
433         *all = nr;
434         weights = xcalloc(on_list, sizeof(*weights));
435
436         /* Do the real work of finding bisection commit. */
437         best = do_find_bisection(list, nr, weights);
438
439         if (best)
440                 best->next = NULL;
441
442         *reaches = weight(best);
443         free(weights);
444
445         return best;
446 }
447
448 static void read_revisions_from_stdin(struct rev_info *revs)
449 {
450         char line[1000];
451
452         while (fgets(line, sizeof(line), stdin) != NULL) {
453                 int len = strlen(line);
454                 if (line[len - 1] == '\n')
455                         line[--len] = 0;
456                 if (!len)
457                         break;
458                 if (line[0] == '-')
459                         die("options not supported in --stdin mode");
460                 if (handle_revision_arg(line, revs, 0, 1))
461                         die("bad revision '%s'", line);
462         }
463 }
464
465 int cmd_rev_list(int argc, const char **argv, const char *prefix)
466 {
467         struct commit_list *list;
468         int i;
469         int read_from_stdin = 0;
470         int bisect_show_vars = 0;
471
472         git_config(git_default_config);
473         init_revisions(&revs, prefix);
474         revs.abbrev = 0;
475         revs.commit_format = CMIT_FMT_UNSPECIFIED;
476         argc = setup_revisions(argc, argv, &revs, NULL);
477
478         for (i = 1 ; i < argc; i++) {
479                 const char *arg = argv[i];
480
481                 if (!strcmp(arg, "--header")) {
482                         revs.verbose_header = 1;
483                         continue;
484                 }
485                 if (!strcmp(arg, "--timestamp")) {
486                         show_timestamp = 1;
487                         continue;
488                 }
489                 if (!strcmp(arg, "--bisect")) {
490                         bisect_list = 1;
491                         continue;
492                 }
493                 if (!strcmp(arg, "--bisect-vars")) {
494                         bisect_list = 1;
495                         bisect_show_vars = 1;
496                         continue;
497                 }
498                 if (!strcmp(arg, "--stdin")) {
499                         if (read_from_stdin++)
500                                 die("--stdin given twice?");
501                         read_revisions_from_stdin(&revs);
502                         continue;
503                 }
504                 usage(rev_list_usage);
505
506         }
507         if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {
508                 /* The command line has a --pretty  */
509                 hdr_termination = '\n';
510                 if (revs.commit_format == CMIT_FMT_ONELINE)
511                         header_prefix = "";
512                 else
513                         header_prefix = "commit ";
514         }
515         else if (revs.verbose_header)
516                 /* Only --header was specified */
517                 revs.commit_format = CMIT_FMT_RAW;
518
519         list = revs.commits;
520
521         if ((!list &&
522              (!(revs.tag_objects||revs.tree_objects||revs.blob_objects) &&
523               !revs.pending.nr)) ||
524             revs.diff)
525                 usage(rev_list_usage);
526
527         save_commit_buffer = revs.verbose_header || revs.grep_filter;
528         track_object_refs = 0;
529         if (bisect_list)
530                 revs.limited = 1;
531
532         prepare_revision_walk(&revs);
533         if (revs.tree_objects)
534                 mark_edges_uninteresting(revs.commits, &revs, show_edge);
535
536         if (bisect_list) {
537                 int reaches = reaches, all = all;
538
539                 revs.commits = find_bisection(revs.commits, &reaches, &all);
540                 if (bisect_show_vars) {
541                         int cnt;
542                         if (!revs.commits)
543                                 return 1;
544                         /*
545                          * revs.commits can reach "reaches" commits among
546                          * "all" commits.  If it is good, then there are
547                          * (all-reaches) commits left to be bisected.
548                          * On the other hand, if it is bad, then the set
549                          * to bisect is "reaches".
550                          * A bisect set of size N has (N-1) commits further
551                          * to test, as we already know one bad one.
552                          */
553                         cnt = all-reaches;
554                         if (cnt < reaches)
555                                 cnt = reaches;
556                         printf("bisect_rev=%s\n"
557                                "bisect_nr=%d\n"
558                                "bisect_good=%d\n"
559                                "bisect_bad=%d\n"
560                                "bisect_all=%d\n",
561                                sha1_to_hex(revs.commits->item->object.sha1),
562                                cnt - 1,
563                                all - reaches - 1,
564                                reaches - 1,
565                                all);
566                         return 0;
567                 }
568         }
569
570         traverse_commit_list(&revs, show_commit, show_object);
571
572         return 0;
573 }