git-merge: no reason to use cpio anymore
[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 distance, 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         distance *= 2;
206         switch (distance - nr) {
207         case -1: case 0: case 1:
208                 return 1;
209         default:
210                 return 0;
211         }
212 }
213
214 #if !DEBUG_BISECT
215 #define show_list(a,b,c,d) do { ; } while (0)
216 #else
217 static void show_list(const char *debug, int counted, int nr,
218                       struct commit_list *list)
219 {
220         struct commit_list *p;
221
222         fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
223
224         for (p = list; p; p = p->next) {
225                 struct commit_list *pp;
226                 struct commit *commit = p->item;
227                 unsigned flags = commit->object.flags;
228                 enum object_type type;
229                 unsigned long size;
230                 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
231                 char *ep, *sp;
232
233                 fprintf(stderr, "%c%c%c ",
234                         (flags & TREECHANGE) ? 'T' : ' ',
235                         (flags & UNINTERESTING) ? 'U' : ' ',
236                         (flags & COUNTED) ? 'C' : ' ');
237                 if (commit->util)
238                         fprintf(stderr, "%3d", weight(p));
239                 else
240                         fprintf(stderr, "---");
241                 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
242                 for (pp = commit->parents; pp; pp = pp->next)
243                         fprintf(stderr, " %.*s", 8,
244                                 sha1_to_hex(pp->item->object.sha1));
245
246                 sp = strstr(buf, "\n\n");
247                 if (sp) {
248                         sp += 2;
249                         for (ep = sp; *ep && *ep != '\n'; ep++)
250                                 ;
251                         fprintf(stderr, " %.*s", (int)(ep - sp), sp);
252                 }
253                 fprintf(stderr, "\n");
254         }
255 }
256 #endif /* DEBUG_BISECT */
257
258 /*
259  * zero or positive weight is the number of interesting commits it can
260  * reach, including itself.  Especially, weight = 0 means it does not
261  * reach any tree-changing commits (e.g. just above uninteresting one
262  * but traversal is with pathspec).
263  *
264  * weight = -1 means it has one parent and its distance is yet to
265  * be computed.
266  *
267  * weight = -2 means it has more than one parent and its distance is
268  * unknown.  After running count_distance() first, they will get zero
269  * or positive distance.
270  */
271
272 static struct commit_list *find_bisection(struct commit_list *list,
273                                           int *reaches, int *all)
274 {
275         int n, nr, on_list, counted, distance;
276         struct commit_list *p, *best, *next, *last;
277         int *weights;
278
279         show_list("bisection 2 entry", 0, 0, list);
280
281         /*
282          * Count the number of total and tree-changing items on the
283          * list, while reversing the list.
284          */
285         for (nr = on_list = 0, last = NULL, p = list;
286              p;
287              p = next) {
288                 unsigned flags = p->item->object.flags;
289
290                 next = p->next;
291                 if (flags & UNINTERESTING)
292                         continue;
293                 p->next = last;
294                 last = p;
295                 if (!revs.prune_fn || (flags & TREECHANGE))
296                         nr++;
297                 on_list++;
298         }
299         list = last;
300         show_list("bisection 2 sorted", 0, nr, list);
301
302         *all = nr;
303         weights = xcalloc(on_list, sizeof(*weights));
304         counted = 0;
305
306         for (n = 0, p = list; p; p = p->next) {
307                 struct commit *commit = p->item;
308                 unsigned flags = commit->object.flags;
309
310                 p->item->util = &weights[n++];
311                 switch (count_interesting_parents(commit)) {
312                 case 0:
313                         if (!revs.prune_fn || (flags & TREECHANGE)) {
314                                 weight_set(p, 1);
315                                 counted++;
316                                 show_list("bisection 2 count one",
317                                           counted, nr, list);
318                         }
319                         /*
320                          * otherwise, it is known not to reach any
321                          * tree-changing commit and gets weight 0.
322                          */
323                         break;
324                 case 1:
325                         weight_set(p, -1);
326                         break;
327                 default:
328                         weight_set(p, -2);
329                         break;
330                 }
331         }
332
333         show_list("bisection 2 initialize", counted, nr, list);
334
335         /*
336          * If you have only one parent in the resulting set
337          * then you can reach one commit more than that parent
338          * can reach.  So we do not have to run the expensive
339          * count_distance() for single strand of pearls.
340          *
341          * However, if you have more than one parents, you cannot
342          * just add their distance and one for yourself, since
343          * they usually reach the same ancestor and you would
344          * end up counting them twice that way.
345          *
346          * So we will first count distance of merges the usual
347          * way, and then fill the blanks using cheaper algorithm.
348          */
349         for (p = list; p; p = p->next) {
350                 if (p->item->object.flags & UNINTERESTING)
351                         continue;
352                 n = weight(p);
353                 if (n != -2)
354                         continue;
355                 distance = count_distance(p);
356                 clear_distance(list);
357                 weight_set(p, distance);
358
359                 /* Does it happen to be at exactly half-way? */
360                 if (halfway(p, distance, nr)) {
361                         p->next = NULL;
362                         *reaches = distance;
363                         free(weights);
364                         return p;
365                 }
366                 counted++;
367         }
368
369         show_list("bisection 2 count_distance", counted, nr, list);
370
371         while (counted < nr) {
372                 for (p = list; p; p = p->next) {
373                         struct commit_list *q;
374                         unsigned flags = p->item->object.flags;
375
376                         if (0 <= weight(p))
377                                 continue;
378                         for (q = p->item->parents; q; q = q->next) {
379                                 if (q->item->object.flags & UNINTERESTING)
380                                         continue;
381                                 if (0 <= weight(q))
382                                         break;
383                         }
384                         if (!q)
385                                 continue;
386
387                         /*
388                          * weight for p is unknown but q is known.
389                          * add one for p itself if p is to be counted,
390                          * otherwise inherit it from q directly.
391                          */
392                         if (!revs.prune_fn || (flags & TREECHANGE)) {
393                                 weight_set(p, weight(q)+1);
394                                 counted++;
395                                 show_list("bisection 2 count one",
396                                           counted, nr, list);
397                         }
398                         else
399                                 weight_set(p, weight(q));
400
401                         /* Does it happen to be at exactly half-way? */
402                         distance = weight(p);
403                         if (halfway(p, distance, nr)) {
404                                 p->next = NULL;
405                                 *reaches = distance;
406                                 free(weights);
407                                 return p;
408                         }
409                 }
410         }
411
412         show_list("bisection 2 counted all", counted, nr, list);
413
414         /* Then find the best one */
415         counted = -1;
416         best = list;
417         for (p = list; p; p = p->next) {
418                 unsigned flags = p->item->object.flags;
419
420                 if (revs.prune_fn && !(flags & TREECHANGE))
421                         continue;
422                 distance = weight(p);
423                 if (nr - distance < distance)
424                         distance = nr - distance;
425                 if (distance > counted) {
426                         best = p;
427                         counted = distance;
428                         *reaches = weight(p);
429                 }
430         }
431         if (best)
432                 best->next = NULL;
433         free(weights);
434         return best;
435 }
436
437 static void read_revisions_from_stdin(struct rev_info *revs)
438 {
439         char line[1000];
440
441         while (fgets(line, sizeof(line), stdin) != NULL) {
442                 int len = strlen(line);
443                 if (line[len - 1] == '\n')
444                         line[--len] = 0;
445                 if (!len)
446                         break;
447                 if (line[0] == '-')
448                         die("options not supported in --stdin mode");
449                 if (handle_revision_arg(line, revs, 0, 1))
450                         die("bad revision '%s'", line);
451         }
452 }
453
454 int cmd_rev_list(int argc, const char **argv, const char *prefix)
455 {
456         struct commit_list *list;
457         int i;
458         int read_from_stdin = 0;
459         int bisect_show_vars = 0;
460
461         git_config(git_default_config);
462         init_revisions(&revs, prefix);
463         revs.abbrev = 0;
464         revs.commit_format = CMIT_FMT_UNSPECIFIED;
465         argc = setup_revisions(argc, argv, &revs, NULL);
466
467         for (i = 1 ; i < argc; i++) {
468                 const char *arg = argv[i];
469
470                 if (!strcmp(arg, "--header")) {
471                         revs.verbose_header = 1;
472                         continue;
473                 }
474                 if (!strcmp(arg, "--timestamp")) {
475                         show_timestamp = 1;
476                         continue;
477                 }
478                 if (!strcmp(arg, "--bisect")) {
479                         bisect_list = 1;
480                         continue;
481                 }
482                 if (!strcmp(arg, "--bisect-vars")) {
483                         bisect_list = 1;
484                         bisect_show_vars = 1;
485                         continue;
486                 }
487                 if (!strcmp(arg, "--stdin")) {
488                         if (read_from_stdin++)
489                                 die("--stdin given twice?");
490                         read_revisions_from_stdin(&revs);
491                         continue;
492                 }
493                 usage(rev_list_usage);
494
495         }
496         if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {
497                 /* The command line has a --pretty  */
498                 hdr_termination = '\n';
499                 if (revs.commit_format == CMIT_FMT_ONELINE)
500                         header_prefix = "";
501                 else
502                         header_prefix = "commit ";
503         }
504         else if (revs.verbose_header)
505                 /* Only --header was specified */
506                 revs.commit_format = CMIT_FMT_RAW;
507
508         list = revs.commits;
509
510         if ((!list &&
511              (!(revs.tag_objects||revs.tree_objects||revs.blob_objects) &&
512               !revs.pending.nr)) ||
513             revs.diff)
514                 usage(rev_list_usage);
515
516         save_commit_buffer = revs.verbose_header || revs.grep_filter;
517         track_object_refs = 0;
518         if (bisect_list)
519                 revs.limited = 1;
520
521         prepare_revision_walk(&revs);
522         if (revs.tree_objects)
523                 mark_edges_uninteresting(revs.commits, &revs, show_edge);
524
525         if (bisect_list) {
526                 int reaches = reaches, all = all;
527
528                 revs.commits = find_bisection(revs.commits, &reaches, &all);
529                 if (bisect_show_vars) {
530                         int cnt;
531                         if (!revs.commits)
532                                 return 1;
533                         /*
534                          * revs.commits can reach "reaches" commits among
535                          * "all" commits.  If it is good, then there are
536                          * (all-reaches) commits left to be bisected.
537                          * On the other hand, if it is bad, then the set
538                          * to bisect is "reaches".
539                          * A bisect set of size N has (N-1) commits further
540                          * to test, as we already know one bad one.
541                          */
542                         cnt = all-reaches;
543                         if (cnt < reaches)
544                                 cnt = reaches;
545                         printf("bisect_rev=%s\n"
546                                "bisect_nr=%d\n"
547                                "bisect_good=%d\n"
548                                "bisect_bad=%d\n"
549                                "bisect_all=%d\n",
550                                sha1_to_hex(revs.commits->item->object.sha1),
551                                cnt - 1,
552                                all - reaches - 1,
553                                reaches - 1,
554                                all);
555                         return 0;
556                 }
557         }
558
559         traverse_commit_list(&revs, show_commit, show_object);
560
561         return 0;
562 }