Merge branch 'jc/maint-reset-remove-unmerged-new'
[git] / builtin-blame.c
1 /*
2  * Pickaxe
3  *
4  * Copyright (c) 2006, Junio C Hamano
5  */
6
7 #include "cache.h"
8 #include "builtin.h"
9 #include "blob.h"
10 #include "commit.h"
11 #include "tag.h"
12 #include "tree-walk.h"
13 #include "diff.h"
14 #include "diffcore.h"
15 #include "revision.h"
16 #include "quote.h"
17 #include "xdiff-interface.h"
18 #include "cache-tree.h"
19 #include "string-list.h"
20 #include "mailmap.h"
21 #include "parse-options.h"
22
23 static char blame_usage[] = "git blame [options] [rev-opts] [rev] [--] file";
24
25 static const char *blame_opt_usage[] = {
26         blame_usage,
27         "",
28         "[rev-opts] are documented in git-rev-list(1)",
29         NULL
30 };
31
32 static int longest_file;
33 static int longest_author;
34 static int max_orig_digits;
35 static int max_digits;
36 static int max_score_digits;
37 static int show_root;
38 static int reverse;
39 static int blank_boundary;
40 static int incremental;
41 static int xdl_opts = XDF_NEED_MINIMAL;
42 static struct string_list mailmap;
43
44 #ifndef DEBUG
45 #define DEBUG 0
46 #endif
47
48 /* stats */
49 static int num_read_blob;
50 static int num_get_patch;
51 static int num_commits;
52
53 #define PICKAXE_BLAME_MOVE              01
54 #define PICKAXE_BLAME_COPY              02
55 #define PICKAXE_BLAME_COPY_HARDER       04
56 #define PICKAXE_BLAME_COPY_HARDEST      010
57
58 /*
59  * blame for a blame_entry with score lower than these thresholds
60  * is not passed to the parent using move/copy logic.
61  */
62 static unsigned blame_move_score;
63 static unsigned blame_copy_score;
64 #define BLAME_DEFAULT_MOVE_SCORE        20
65 #define BLAME_DEFAULT_COPY_SCORE        40
66
67 /* bits #0..7 in revision.h, #8..11 used for merge_bases() in commit.c */
68 #define METAINFO_SHOWN          (1u<<12)
69 #define MORE_THAN_ONE_PATH      (1u<<13)
70
71 /*
72  * One blob in a commit that is being suspected
73  */
74 struct origin {
75         int refcnt;
76         struct commit *commit;
77         mmfile_t file;
78         unsigned char blob_sha1[20];
79         char path[FLEX_ARRAY];
80 };
81
82 /*
83  * Given an origin, prepare mmfile_t structure to be used by the
84  * diff machinery
85  */
86 static void fill_origin_blob(struct origin *o, mmfile_t *file)
87 {
88         if (!o->file.ptr) {
89                 enum object_type type;
90                 num_read_blob++;
91                 file->ptr = read_sha1_file(o->blob_sha1, &type,
92                                            (unsigned long *)(&(file->size)));
93                 if (!file->ptr)
94                         die("Cannot read blob %s for path %s",
95                             sha1_to_hex(o->blob_sha1),
96                             o->path);
97                 o->file = *file;
98         }
99         else
100                 *file = o->file;
101 }
102
103 /*
104  * Origin is refcounted and usually we keep the blob contents to be
105  * reused.
106  */
107 static inline struct origin *origin_incref(struct origin *o)
108 {
109         if (o)
110                 o->refcnt++;
111         return o;
112 }
113
114 static void origin_decref(struct origin *o)
115 {
116         if (o && --o->refcnt <= 0) {
117                 free(o->file.ptr);
118                 free(o);
119         }
120 }
121
122 static void drop_origin_blob(struct origin *o)
123 {
124         if (o->file.ptr) {
125                 free(o->file.ptr);
126                 o->file.ptr = NULL;
127         }
128 }
129
130 /*
131  * Each group of lines is described by a blame_entry; it can be split
132  * as we pass blame to the parents.  They form a linked list in the
133  * scoreboard structure, sorted by the target line number.
134  */
135 struct blame_entry {
136         struct blame_entry *prev;
137         struct blame_entry *next;
138
139         /* the first line of this group in the final image;
140          * internally all line numbers are 0 based.
141          */
142         int lno;
143
144         /* how many lines this group has */
145         int num_lines;
146
147         /* the commit that introduced this group into the final image */
148         struct origin *suspect;
149
150         /* true if the suspect is truly guilty; false while we have not
151          * checked if the group came from one of its parents.
152          */
153         char guilty;
154
155         /* true if the entry has been scanned for copies in the current parent
156          */
157         char scanned;
158
159         /* the line number of the first line of this group in the
160          * suspect's file; internally all line numbers are 0 based.
161          */
162         int s_lno;
163
164         /* how significant this entry is -- cached to avoid
165          * scanning the lines over and over.
166          */
167         unsigned score;
168 };
169
170 /*
171  * The current state of the blame assignment.
172  */
173 struct scoreboard {
174         /* the final commit (i.e. where we started digging from) */
175         struct commit *final;
176         struct rev_info *revs;
177         const char *path;
178
179         /*
180          * The contents in the final image.
181          * Used by many functions to obtain contents of the nth line,
182          * indexed with scoreboard.lineno[blame_entry.lno].
183          */
184         const char *final_buf;
185         unsigned long final_buf_size;
186
187         /* linked list of blames */
188         struct blame_entry *ent;
189
190         /* look-up a line in the final buffer */
191         int num_lines;
192         int *lineno;
193 };
194
195 static inline int same_suspect(struct origin *a, struct origin *b)
196 {
197         if (a == b)
198                 return 1;
199         if (a->commit != b->commit)
200                 return 0;
201         return !strcmp(a->path, b->path);
202 }
203
204 static void sanity_check_refcnt(struct scoreboard *);
205
206 /*
207  * If two blame entries that are next to each other came from
208  * contiguous lines in the same origin (i.e. <commit, path> pair),
209  * merge them together.
210  */
211 static void coalesce(struct scoreboard *sb)
212 {
213         struct blame_entry *ent, *next;
214
215         for (ent = sb->ent; ent && (next = ent->next); ent = next) {
216                 if (same_suspect(ent->suspect, next->suspect) &&
217                     ent->guilty == next->guilty &&
218                     ent->s_lno + ent->num_lines == next->s_lno) {
219                         ent->num_lines += next->num_lines;
220                         ent->next = next->next;
221                         if (ent->next)
222                                 ent->next->prev = ent;
223                         origin_decref(next->suspect);
224                         free(next);
225                         ent->score = 0;
226                         next = ent; /* again */
227                 }
228         }
229
230         if (DEBUG) /* sanity */
231                 sanity_check_refcnt(sb);
232 }
233
234 /*
235  * Given a commit and a path in it, create a new origin structure.
236  * The callers that add blame to the scoreboard should use
237  * get_origin() to obtain shared, refcounted copy instead of calling
238  * this function directly.
239  */
240 static struct origin *make_origin(struct commit *commit, const char *path)
241 {
242         struct origin *o;
243         o = xcalloc(1, sizeof(*o) + strlen(path) + 1);
244         o->commit = commit;
245         o->refcnt = 1;
246         strcpy(o->path, path);
247         return o;
248 }
249
250 /*
251  * Locate an existing origin or create a new one.
252  */
253 static struct origin *get_origin(struct scoreboard *sb,
254                                  struct commit *commit,
255                                  const char *path)
256 {
257         struct blame_entry *e;
258
259         for (e = sb->ent; e; e = e->next) {
260                 if (e->suspect->commit == commit &&
261                     !strcmp(e->suspect->path, path))
262                         return origin_incref(e->suspect);
263         }
264         return make_origin(commit, path);
265 }
266
267 /*
268  * Fill the blob_sha1 field of an origin if it hasn't, so that later
269  * call to fill_origin_blob() can use it to locate the data.  blob_sha1
270  * for an origin is also used to pass the blame for the entire file to
271  * the parent to detect the case where a child's blob is identical to
272  * that of its parent's.
273  */
274 static int fill_blob_sha1(struct origin *origin)
275 {
276         unsigned mode;
277
278         if (!is_null_sha1(origin->blob_sha1))
279                 return 0;
280         if (get_tree_entry(origin->commit->object.sha1,
281                            origin->path,
282                            origin->blob_sha1, &mode))
283                 goto error_out;
284         if (sha1_object_info(origin->blob_sha1, NULL) != OBJ_BLOB)
285                 goto error_out;
286         return 0;
287  error_out:
288         hashclr(origin->blob_sha1);
289         return -1;
290 }
291
292 /*
293  * We have an origin -- check if the same path exists in the
294  * parent and return an origin structure to represent it.
295  */
296 static struct origin *find_origin(struct scoreboard *sb,
297                                   struct commit *parent,
298                                   struct origin *origin)
299 {
300         struct origin *porigin = NULL;
301         struct diff_options diff_opts;
302         const char *paths[2];
303
304         if (parent->util) {
305                 /*
306                  * Each commit object can cache one origin in that
307                  * commit.  This is a freestanding copy of origin and
308                  * not refcounted.
309                  */
310                 struct origin *cached = parent->util;
311                 if (!strcmp(cached->path, origin->path)) {
312                         /*
313                          * The same path between origin and its parent
314                          * without renaming -- the most common case.
315                          */
316                         porigin = get_origin(sb, parent, cached->path);
317
318                         /*
319                          * If the origin was newly created (i.e. get_origin
320                          * would call make_origin if none is found in the
321                          * scoreboard), it does not know the blob_sha1,
322                          * so copy it.  Otherwise porigin was in the
323                          * scoreboard and already knows blob_sha1.
324                          */
325                         if (porigin->refcnt == 1)
326                                 hashcpy(porigin->blob_sha1, cached->blob_sha1);
327                         return porigin;
328                 }
329                 /* otherwise it was not very useful; free it */
330                 free(parent->util);
331                 parent->util = NULL;
332         }
333
334         /* See if the origin->path is different between parent
335          * and origin first.  Most of the time they are the
336          * same and diff-tree is fairly efficient about this.
337          */
338         diff_setup(&diff_opts);
339         DIFF_OPT_SET(&diff_opts, RECURSIVE);
340         diff_opts.detect_rename = 0;
341         diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
342         paths[0] = origin->path;
343         paths[1] = NULL;
344
345         diff_tree_setup_paths(paths, &diff_opts);
346         if (diff_setup_done(&diff_opts) < 0)
347                 die("diff-setup");
348
349         if (is_null_sha1(origin->commit->object.sha1))
350                 do_diff_cache(parent->tree->object.sha1, &diff_opts);
351         else
352                 diff_tree_sha1(parent->tree->object.sha1,
353                                origin->commit->tree->object.sha1,
354                                "", &diff_opts);
355         diffcore_std(&diff_opts);
356
357         /* It is either one entry that says "modified", or "created",
358          * or nothing.
359          */
360         if (!diff_queued_diff.nr) {
361                 /* The path is the same as parent */
362                 porigin = get_origin(sb, parent, origin->path);
363                 hashcpy(porigin->blob_sha1, origin->blob_sha1);
364         }
365         else if (diff_queued_diff.nr != 1)
366                 die("internal error in blame::find_origin");
367         else {
368                 struct diff_filepair *p = diff_queued_diff.queue[0];
369                 switch (p->status) {
370                 default:
371                         die("internal error in blame::find_origin (%c)",
372                             p->status);
373                 case 'M':
374                         porigin = get_origin(sb, parent, origin->path);
375                         hashcpy(porigin->blob_sha1, p->one->sha1);
376                         break;
377                 case 'A':
378                 case 'T':
379                         /* Did not exist in parent, or type changed */
380                         break;
381                 }
382         }
383         diff_flush(&diff_opts);
384         diff_tree_release_paths(&diff_opts);
385         if (porigin) {
386                 /*
387                  * Create a freestanding copy that is not part of
388                  * the refcounted origin found in the scoreboard, and
389                  * cache it in the commit.
390                  */
391                 struct origin *cached;
392
393                 cached = make_origin(porigin->commit, porigin->path);
394                 hashcpy(cached->blob_sha1, porigin->blob_sha1);
395                 parent->util = cached;
396         }
397         return porigin;
398 }
399
400 /*
401  * We have an origin -- find the path that corresponds to it in its
402  * parent and return an origin structure to represent it.
403  */
404 static struct origin *find_rename(struct scoreboard *sb,
405                                   struct commit *parent,
406                                   struct origin *origin)
407 {
408         struct origin *porigin = NULL;
409         struct diff_options diff_opts;
410         int i;
411         const char *paths[2];
412
413         diff_setup(&diff_opts);
414         DIFF_OPT_SET(&diff_opts, RECURSIVE);
415         diff_opts.detect_rename = DIFF_DETECT_RENAME;
416         diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
417         diff_opts.single_follow = origin->path;
418         paths[0] = NULL;
419         diff_tree_setup_paths(paths, &diff_opts);
420         if (diff_setup_done(&diff_opts) < 0)
421                 die("diff-setup");
422
423         if (is_null_sha1(origin->commit->object.sha1))
424                 do_diff_cache(parent->tree->object.sha1, &diff_opts);
425         else
426                 diff_tree_sha1(parent->tree->object.sha1,
427                                origin->commit->tree->object.sha1,
428                                "", &diff_opts);
429         diffcore_std(&diff_opts);
430
431         for (i = 0; i < diff_queued_diff.nr; i++) {
432                 struct diff_filepair *p = diff_queued_diff.queue[i];
433                 if ((p->status == 'R' || p->status == 'C') &&
434                     !strcmp(p->two->path, origin->path)) {
435                         porigin = get_origin(sb, parent, p->one->path);
436                         hashcpy(porigin->blob_sha1, p->one->sha1);
437                         break;
438                 }
439         }
440         diff_flush(&diff_opts);
441         diff_tree_release_paths(&diff_opts);
442         return porigin;
443 }
444
445 /*
446  * Parsing of patch chunks...
447  */
448 struct chunk {
449         /* line number in postimage; up to but not including this
450          * line is the same as preimage
451          */
452         int same;
453
454         /* preimage line number after this chunk */
455         int p_next;
456
457         /* postimage line number after this chunk */
458         int t_next;
459 };
460
461 struct patch {
462         struct chunk *chunks;
463         int num;
464 };
465
466 struct blame_diff_state {
467         struct patch *ret;
468         unsigned hunk_post_context;
469         unsigned hunk_in_pre_context : 1;
470 };
471
472 static void process_u_diff(void *state_, char *line, unsigned long len)
473 {
474         struct blame_diff_state *state = state_;
475         struct chunk *chunk;
476         int off1, off2, len1, len2, num;
477
478         num = state->ret->num;
479         if (len < 4 || line[0] != '@' || line[1] != '@') {
480                 if (state->hunk_in_pre_context && line[0] == ' ')
481                         state->ret->chunks[num - 1].same++;
482                 else {
483                         state->hunk_in_pre_context = 0;
484                         if (line[0] == ' ')
485                                 state->hunk_post_context++;
486                         else
487                                 state->hunk_post_context = 0;
488                 }
489                 return;
490         }
491
492         if (num && state->hunk_post_context) {
493                 chunk = &state->ret->chunks[num - 1];
494                 chunk->p_next -= state->hunk_post_context;
495                 chunk->t_next -= state->hunk_post_context;
496         }
497         state->ret->num = ++num;
498         state->ret->chunks = xrealloc(state->ret->chunks,
499                                       sizeof(struct chunk) * num);
500         chunk = &state->ret->chunks[num - 1];
501         if (parse_hunk_header(line, len, &off1, &len1, &off2, &len2)) {
502                 state->ret->num--;
503                 return;
504         }
505
506         /* Line numbers in patch output are one based. */
507         off1--;
508         off2--;
509
510         chunk->same = len2 ? off2 : (off2 + 1);
511
512         chunk->p_next = off1 + (len1 ? len1 : 1);
513         chunk->t_next = chunk->same + len2;
514         state->hunk_in_pre_context = 1;
515         state->hunk_post_context = 0;
516 }
517
518 static struct patch *compare_buffer(mmfile_t *file_p, mmfile_t *file_o,
519                                     int context)
520 {
521         struct blame_diff_state state;
522         xpparam_t xpp;
523         xdemitconf_t xecfg;
524         xdemitcb_t ecb;
525
526         xpp.flags = xdl_opts;
527         memset(&xecfg, 0, sizeof(xecfg));
528         xecfg.ctxlen = context;
529         memset(&state, 0, sizeof(state));
530         state.ret = xmalloc(sizeof(struct patch));
531         state.ret->chunks = NULL;
532         state.ret->num = 0;
533
534         xdi_diff_outf(file_p, file_o, process_u_diff, &state, &xpp, &xecfg, &ecb);
535
536         if (state.ret->num) {
537                 struct chunk *chunk;
538                 chunk = &state.ret->chunks[state.ret->num - 1];
539                 chunk->p_next -= state.hunk_post_context;
540                 chunk->t_next -= state.hunk_post_context;
541         }
542         return state.ret;
543 }
544
545 /*
546  * Run diff between two origins and grab the patch output, so that
547  * we can pass blame for lines origin is currently suspected for
548  * to its parent.
549  */
550 static struct patch *get_patch(struct origin *parent, struct origin *origin)
551 {
552         mmfile_t file_p, file_o;
553         struct patch *patch;
554
555         fill_origin_blob(parent, &file_p);
556         fill_origin_blob(origin, &file_o);
557         if (!file_p.ptr || !file_o.ptr)
558                 return NULL;
559         patch = compare_buffer(&file_p, &file_o, 0);
560         num_get_patch++;
561         return patch;
562 }
563
564 static void free_patch(struct patch *p)
565 {
566         free(p->chunks);
567         free(p);
568 }
569
570 /*
571  * Link in a new blame entry to the scoreboard.  Entries that cover the
572  * same line range have been removed from the scoreboard previously.
573  */
574 static void add_blame_entry(struct scoreboard *sb, struct blame_entry *e)
575 {
576         struct blame_entry *ent, *prev = NULL;
577
578         origin_incref(e->suspect);
579
580         for (ent = sb->ent; ent && ent->lno < e->lno; ent = ent->next)
581                 prev = ent;
582
583         /* prev, if not NULL, is the last one that is below e */
584         e->prev = prev;
585         if (prev) {
586                 e->next = prev->next;
587                 prev->next = e;
588         }
589         else {
590                 e->next = sb->ent;
591                 sb->ent = e;
592         }
593         if (e->next)
594                 e->next->prev = e;
595 }
596
597 /*
598  * src typically is on-stack; we want to copy the information in it to
599  * a malloced blame_entry that is already on the linked list of the
600  * scoreboard.  The origin of dst loses a refcnt while the origin of src
601  * gains one.
602  */
603 static void dup_entry(struct blame_entry *dst, struct blame_entry *src)
604 {
605         struct blame_entry *p, *n;
606
607         p = dst->prev;
608         n = dst->next;
609         origin_incref(src->suspect);
610         origin_decref(dst->suspect);
611         memcpy(dst, src, sizeof(*src));
612         dst->prev = p;
613         dst->next = n;
614         dst->score = 0;
615 }
616
617 static const char *nth_line(struct scoreboard *sb, int lno)
618 {
619         return sb->final_buf + sb->lineno[lno];
620 }
621
622 /*
623  * It is known that lines between tlno to same came from parent, and e
624  * has an overlap with that range.  it also is known that parent's
625  * line plno corresponds to e's line tlno.
626  *
627  *                <---- e ----->
628  *                   <------>
629  *                   <------------>
630  *             <------------>
631  *             <------------------>
632  *
633  * Split e into potentially three parts; before this chunk, the chunk
634  * to be blamed for the parent, and after that portion.
635  */
636 static void split_overlap(struct blame_entry *split,
637                           struct blame_entry *e,
638                           int tlno, int plno, int same,
639                           struct origin *parent)
640 {
641         int chunk_end_lno;
642         memset(split, 0, sizeof(struct blame_entry [3]));
643
644         if (e->s_lno < tlno) {
645                 /* there is a pre-chunk part not blamed on parent */
646                 split[0].suspect = origin_incref(e->suspect);
647                 split[0].lno = e->lno;
648                 split[0].s_lno = e->s_lno;
649                 split[0].num_lines = tlno - e->s_lno;
650                 split[1].lno = e->lno + tlno - e->s_lno;
651                 split[1].s_lno = plno;
652         }
653         else {
654                 split[1].lno = e->lno;
655                 split[1].s_lno = plno + (e->s_lno - tlno);
656         }
657
658         if (same < e->s_lno + e->num_lines) {
659                 /* there is a post-chunk part not blamed on parent */
660                 split[2].suspect = origin_incref(e->suspect);
661                 split[2].lno = e->lno + (same - e->s_lno);
662                 split[2].s_lno = e->s_lno + (same - e->s_lno);
663                 split[2].num_lines = e->s_lno + e->num_lines - same;
664                 chunk_end_lno = split[2].lno;
665         }
666         else
667                 chunk_end_lno = e->lno + e->num_lines;
668         split[1].num_lines = chunk_end_lno - split[1].lno;
669
670         /*
671          * if it turns out there is nothing to blame the parent for,
672          * forget about the splitting.  !split[1].suspect signals this.
673          */
674         if (split[1].num_lines < 1)
675                 return;
676         split[1].suspect = origin_incref(parent);
677 }
678
679 /*
680  * split_overlap() divided an existing blame e into up to three parts
681  * in split.  Adjust the linked list of blames in the scoreboard to
682  * reflect the split.
683  */
684 static void split_blame(struct scoreboard *sb,
685                         struct blame_entry *split,
686                         struct blame_entry *e)
687 {
688         struct blame_entry *new_entry;
689
690         if (split[0].suspect && split[2].suspect) {
691                 /* The first part (reuse storage for the existing entry e) */
692                 dup_entry(e, &split[0]);
693
694                 /* The last part -- me */
695                 new_entry = xmalloc(sizeof(*new_entry));
696                 memcpy(new_entry, &(split[2]), sizeof(struct blame_entry));
697                 add_blame_entry(sb, new_entry);
698
699                 /* ... and the middle part -- parent */
700                 new_entry = xmalloc(sizeof(*new_entry));
701                 memcpy(new_entry, &(split[1]), sizeof(struct blame_entry));
702                 add_blame_entry(sb, new_entry);
703         }
704         else if (!split[0].suspect && !split[2].suspect)
705                 /*
706                  * The parent covers the entire area; reuse storage for
707                  * e and replace it with the parent.
708                  */
709                 dup_entry(e, &split[1]);
710         else if (split[0].suspect) {
711                 /* me and then parent */
712                 dup_entry(e, &split[0]);
713
714                 new_entry = xmalloc(sizeof(*new_entry));
715                 memcpy(new_entry, &(split[1]), sizeof(struct blame_entry));
716                 add_blame_entry(sb, new_entry);
717         }
718         else {
719                 /* parent and then me */
720                 dup_entry(e, &split[1]);
721
722                 new_entry = xmalloc(sizeof(*new_entry));
723                 memcpy(new_entry, &(split[2]), sizeof(struct blame_entry));
724                 add_blame_entry(sb, new_entry);
725         }
726
727         if (DEBUG) { /* sanity */
728                 struct blame_entry *ent;
729                 int lno = sb->ent->lno, corrupt = 0;
730
731                 for (ent = sb->ent; ent; ent = ent->next) {
732                         if (lno != ent->lno)
733                                 corrupt = 1;
734                         if (ent->s_lno < 0)
735                                 corrupt = 1;
736                         lno += ent->num_lines;
737                 }
738                 if (corrupt) {
739                         lno = sb->ent->lno;
740                         for (ent = sb->ent; ent; ent = ent->next) {
741                                 printf("L %8d l %8d n %8d\n",
742                                        lno, ent->lno, ent->num_lines);
743                                 lno = ent->lno + ent->num_lines;
744                         }
745                         die("oops");
746                 }
747         }
748 }
749
750 /*
751  * After splitting the blame, the origins used by the
752  * on-stack blame_entry should lose one refcnt each.
753  */
754 static void decref_split(struct blame_entry *split)
755 {
756         int i;
757
758         for (i = 0; i < 3; i++)
759                 origin_decref(split[i].suspect);
760 }
761
762 /*
763  * Helper for blame_chunk().  blame_entry e is known to overlap with
764  * the patch hunk; split it and pass blame to the parent.
765  */
766 static void blame_overlap(struct scoreboard *sb, struct blame_entry *e,
767                           int tlno, int plno, int same,
768                           struct origin *parent)
769 {
770         struct blame_entry split[3];
771
772         split_overlap(split, e, tlno, plno, same, parent);
773         if (split[1].suspect)
774                 split_blame(sb, split, e);
775         decref_split(split);
776 }
777
778 /*
779  * Find the line number of the last line the target is suspected for.
780  */
781 static int find_last_in_target(struct scoreboard *sb, struct origin *target)
782 {
783         struct blame_entry *e;
784         int last_in_target = -1;
785
786         for (e = sb->ent; e; e = e->next) {
787                 if (e->guilty || !same_suspect(e->suspect, target))
788                         continue;
789                 if (last_in_target < e->s_lno + e->num_lines)
790                         last_in_target = e->s_lno + e->num_lines;
791         }
792         return last_in_target;
793 }
794
795 /*
796  * Process one hunk from the patch between the current suspect for
797  * blame_entry e and its parent.  Find and split the overlap, and
798  * pass blame to the overlapping part to the parent.
799  */
800 static void blame_chunk(struct scoreboard *sb,
801                         int tlno, int plno, int same,
802                         struct origin *target, struct origin *parent)
803 {
804         struct blame_entry *e;
805
806         for (e = sb->ent; e; e = e->next) {
807                 if (e->guilty || !same_suspect(e->suspect, target))
808                         continue;
809                 if (same <= e->s_lno)
810                         continue;
811                 if (tlno < e->s_lno + e->num_lines)
812                         blame_overlap(sb, e, tlno, plno, same, parent);
813         }
814 }
815
816 /*
817  * We are looking at the origin 'target' and aiming to pass blame
818  * for the lines it is suspected to its parent.  Run diff to find
819  * which lines came from parent and pass blame for them.
820  */
821 static int pass_blame_to_parent(struct scoreboard *sb,
822                                 struct origin *target,
823                                 struct origin *parent)
824 {
825         int i, last_in_target, plno, tlno;
826         struct patch *patch;
827
828         last_in_target = find_last_in_target(sb, target);
829         if (last_in_target < 0)
830                 return 1; /* nothing remains for this target */
831
832         patch = get_patch(parent, target);
833         plno = tlno = 0;
834         for (i = 0; i < patch->num; i++) {
835                 struct chunk *chunk = &patch->chunks[i];
836
837                 blame_chunk(sb, tlno, plno, chunk->same, target, parent);
838                 plno = chunk->p_next;
839                 tlno = chunk->t_next;
840         }
841         /* The rest (i.e. anything after tlno) are the same as the parent */
842         blame_chunk(sb, tlno, plno, last_in_target, target, parent);
843
844         free_patch(patch);
845         return 0;
846 }
847
848 /*
849  * The lines in blame_entry after splitting blames many times can become
850  * very small and trivial, and at some point it becomes pointless to
851  * blame the parents.  E.g. "\t\t}\n\t}\n\n" appears everywhere in any
852  * ordinary C program, and it is not worth to say it was copied from
853  * totally unrelated file in the parent.
854  *
855  * Compute how trivial the lines in the blame_entry are.
856  */
857 static unsigned ent_score(struct scoreboard *sb, struct blame_entry *e)
858 {
859         unsigned score;
860         const char *cp, *ep;
861
862         if (e->score)
863                 return e->score;
864
865         score = 1;
866         cp = nth_line(sb, e->lno);
867         ep = nth_line(sb, e->lno + e->num_lines);
868         while (cp < ep) {
869                 unsigned ch = *((unsigned char *)cp);
870                 if (isalnum(ch))
871                         score++;
872                 cp++;
873         }
874         e->score = score;
875         return score;
876 }
877
878 /*
879  * best_so_far[] and this[] are both a split of an existing blame_entry
880  * that passes blame to the parent.  Maintain best_so_far the best split
881  * so far, by comparing this and best_so_far and copying this into
882  * bst_so_far as needed.
883  */
884 static void copy_split_if_better(struct scoreboard *sb,
885                                  struct blame_entry *best_so_far,
886                                  struct blame_entry *this)
887 {
888         int i;
889
890         if (!this[1].suspect)
891                 return;
892         if (best_so_far[1].suspect) {
893                 if (ent_score(sb, &this[1]) < ent_score(sb, &best_so_far[1]))
894                         return;
895         }
896
897         for (i = 0; i < 3; i++)
898                 origin_incref(this[i].suspect);
899         decref_split(best_so_far);
900         memcpy(best_so_far, this, sizeof(struct blame_entry [3]));
901 }
902
903 /*
904  * We are looking at a part of the final image represented by
905  * ent (tlno and same are offset by ent->s_lno).
906  * tlno is where we are looking at in the final image.
907  * up to (but not including) same match preimage.
908  * plno is where we are looking at in the preimage.
909  *
910  * <-------------- final image ---------------------->
911  *       <------ent------>
912  *         ^tlno ^same
913  *    <---------preimage----->
914  *         ^plno
915  *
916  * All line numbers are 0-based.
917  */
918 static void handle_split(struct scoreboard *sb,
919                          struct blame_entry *ent,
920                          int tlno, int plno, int same,
921                          struct origin *parent,
922                          struct blame_entry *split)
923 {
924         if (ent->num_lines <= tlno)
925                 return;
926         if (tlno < same) {
927                 struct blame_entry this[3];
928                 tlno += ent->s_lno;
929                 same += ent->s_lno;
930                 split_overlap(this, ent, tlno, plno, same, parent);
931                 copy_split_if_better(sb, split, this);
932                 decref_split(this);
933         }
934 }
935
936 /*
937  * Find the lines from parent that are the same as ent so that
938  * we can pass blames to it.  file_p has the blob contents for
939  * the parent.
940  */
941 static void find_copy_in_blob(struct scoreboard *sb,
942                               struct blame_entry *ent,
943                               struct origin *parent,
944                               struct blame_entry *split,
945                               mmfile_t *file_p)
946 {
947         const char *cp;
948         int cnt;
949         mmfile_t file_o;
950         struct patch *patch;
951         int i, plno, tlno;
952
953         /*
954          * Prepare mmfile that contains only the lines in ent.
955          */
956         cp = nth_line(sb, ent->lno);
957         file_o.ptr = (char*) cp;
958         cnt = ent->num_lines;
959
960         while (cnt && cp < sb->final_buf + sb->final_buf_size) {
961                 if (*cp++ == '\n')
962                         cnt--;
963         }
964         file_o.size = cp - file_o.ptr;
965
966         patch = compare_buffer(file_p, &file_o, 1);
967
968         /*
969          * file_o is a part of final image we are annotating.
970          * file_p partially may match that image.
971          */
972         memset(split, 0, sizeof(struct blame_entry [3]));
973         plno = tlno = 0;
974         for (i = 0; i < patch->num; i++) {
975                 struct chunk *chunk = &patch->chunks[i];
976
977                 handle_split(sb, ent, tlno, plno, chunk->same, parent, split);
978                 plno = chunk->p_next;
979                 tlno = chunk->t_next;
980         }
981         /* remainder, if any, all match the preimage */
982         handle_split(sb, ent, tlno, plno, ent->num_lines, parent, split);
983         free_patch(patch);
984 }
985
986 /*
987  * See if lines currently target is suspected for can be attributed to
988  * parent.
989  */
990 static int find_move_in_parent(struct scoreboard *sb,
991                                struct origin *target,
992                                struct origin *parent)
993 {
994         int last_in_target, made_progress;
995         struct blame_entry *e, split[3];
996         mmfile_t file_p;
997
998         last_in_target = find_last_in_target(sb, target);
999         if (last_in_target < 0)
1000                 return 1; /* nothing remains for this target */
1001
1002         fill_origin_blob(parent, &file_p);
1003         if (!file_p.ptr)
1004                 return 0;
1005
1006         made_progress = 1;
1007         while (made_progress) {
1008                 made_progress = 0;
1009                 for (e = sb->ent; e; e = e->next) {
1010                         if (e->guilty || !same_suspect(e->suspect, target) ||
1011                             ent_score(sb, e) < blame_move_score)
1012                                 continue;
1013                         find_copy_in_blob(sb, e, parent, split, &file_p);
1014                         if (split[1].suspect &&
1015                             blame_move_score < ent_score(sb, &split[1])) {
1016                                 split_blame(sb, split, e);
1017                                 made_progress = 1;
1018                         }
1019                         decref_split(split);
1020                 }
1021         }
1022         return 0;
1023 }
1024
1025 struct blame_list {
1026         struct blame_entry *ent;
1027         struct blame_entry split[3];
1028 };
1029
1030 /*
1031  * Count the number of entries the target is suspected for,
1032  * and prepare a list of entry and the best split.
1033  */
1034 static struct blame_list *setup_blame_list(struct scoreboard *sb,
1035                                            struct origin *target,
1036                                            int min_score,
1037                                            int *num_ents_p)
1038 {
1039         struct blame_entry *e;
1040         int num_ents, i;
1041         struct blame_list *blame_list = NULL;
1042
1043         for (e = sb->ent, num_ents = 0; e; e = e->next)
1044                 if (!e->scanned && !e->guilty &&
1045                     same_suspect(e->suspect, target) &&
1046                     min_score < ent_score(sb, e))
1047                         num_ents++;
1048         if (num_ents) {
1049                 blame_list = xcalloc(num_ents, sizeof(struct blame_list));
1050                 for (e = sb->ent, i = 0; e; e = e->next)
1051                         if (!e->scanned && !e->guilty &&
1052                             same_suspect(e->suspect, target) &&
1053                             min_score < ent_score(sb, e))
1054                                 blame_list[i++].ent = e;
1055         }
1056         *num_ents_p = num_ents;
1057         return blame_list;
1058 }
1059
1060 /*
1061  * Reset the scanned status on all entries.
1062  */
1063 static void reset_scanned_flag(struct scoreboard *sb)
1064 {
1065         struct blame_entry *e;
1066         for (e = sb->ent; e; e = e->next)
1067                 e->scanned = 0;
1068 }
1069
1070 /*
1071  * For lines target is suspected for, see if we can find code movement
1072  * across file boundary from the parent commit.  porigin is the path
1073  * in the parent we already tried.
1074  */
1075 static int find_copy_in_parent(struct scoreboard *sb,
1076                                struct origin *target,
1077                                struct commit *parent,
1078                                struct origin *porigin,
1079                                int opt)
1080 {
1081         struct diff_options diff_opts;
1082         const char *paths[1];
1083         int i, j;
1084         int retval;
1085         struct blame_list *blame_list;
1086         int num_ents;
1087
1088         blame_list = setup_blame_list(sb, target, blame_copy_score, &num_ents);
1089         if (!blame_list)
1090                 return 1; /* nothing remains for this target */
1091
1092         diff_setup(&diff_opts);
1093         DIFF_OPT_SET(&diff_opts, RECURSIVE);
1094         diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1095
1096         paths[0] = NULL;
1097         diff_tree_setup_paths(paths, &diff_opts);
1098         if (diff_setup_done(&diff_opts) < 0)
1099                 die("diff-setup");
1100
1101         /* Try "find copies harder" on new path if requested;
1102          * we do not want to use diffcore_rename() actually to
1103          * match things up; find_copies_harder is set only to
1104          * force diff_tree_sha1() to feed all filepairs to diff_queue,
1105          * and this code needs to be after diff_setup_done(), which
1106          * usually makes find-copies-harder imply copy detection.
1107          */
1108         if ((opt & PICKAXE_BLAME_COPY_HARDEST)
1109             || ((opt & PICKAXE_BLAME_COPY_HARDER)
1110                 && (!porigin || strcmp(target->path, porigin->path))))
1111                 DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
1112
1113         if (is_null_sha1(target->commit->object.sha1))
1114                 do_diff_cache(parent->tree->object.sha1, &diff_opts);
1115         else
1116                 diff_tree_sha1(parent->tree->object.sha1,
1117                                target->commit->tree->object.sha1,
1118                                "", &diff_opts);
1119
1120         if (!DIFF_OPT_TST(&diff_opts, FIND_COPIES_HARDER))
1121                 diffcore_std(&diff_opts);
1122
1123         retval = 0;
1124         while (1) {
1125                 int made_progress = 0;
1126
1127                 for (i = 0; i < diff_queued_diff.nr; i++) {
1128                         struct diff_filepair *p = diff_queued_diff.queue[i];
1129                         struct origin *norigin;
1130                         mmfile_t file_p;
1131                         struct blame_entry this[3];
1132
1133                         if (!DIFF_FILE_VALID(p->one))
1134                                 continue; /* does not exist in parent */
1135                         if (S_ISGITLINK(p->one->mode))
1136                                 continue; /* ignore git links */
1137                         if (porigin && !strcmp(p->one->path, porigin->path))
1138                                 /* find_move already dealt with this path */
1139                                 continue;
1140
1141                         norigin = get_origin(sb, parent, p->one->path);
1142                         hashcpy(norigin->blob_sha1, p->one->sha1);
1143                         fill_origin_blob(norigin, &file_p);
1144                         if (!file_p.ptr)
1145                                 continue;
1146
1147                         for (j = 0; j < num_ents; j++) {
1148                                 find_copy_in_blob(sb, blame_list[j].ent,
1149                                                   norigin, this, &file_p);
1150                                 copy_split_if_better(sb, blame_list[j].split,
1151                                                      this);
1152                                 decref_split(this);
1153                         }
1154                         origin_decref(norigin);
1155                 }
1156
1157                 for (j = 0; j < num_ents; j++) {
1158                         struct blame_entry *split = blame_list[j].split;
1159                         if (split[1].suspect &&
1160                             blame_copy_score < ent_score(sb, &split[1])) {
1161                                 split_blame(sb, split, blame_list[j].ent);
1162                                 made_progress = 1;
1163                         }
1164                         else
1165                                 blame_list[j].ent->scanned = 1;
1166                         decref_split(split);
1167                 }
1168                 free(blame_list);
1169
1170                 if (!made_progress)
1171                         break;
1172                 blame_list = setup_blame_list(sb, target, blame_copy_score, &num_ents);
1173                 if (!blame_list) {
1174                         retval = 1;
1175                         break;
1176                 }
1177         }
1178         reset_scanned_flag(sb);
1179         diff_flush(&diff_opts);
1180         diff_tree_release_paths(&diff_opts);
1181         return retval;
1182 }
1183
1184 /*
1185  * The blobs of origin and porigin exactly match, so everything
1186  * origin is suspected for can be blamed on the parent.
1187  */
1188 static void pass_whole_blame(struct scoreboard *sb,
1189                              struct origin *origin, struct origin *porigin)
1190 {
1191         struct blame_entry *e;
1192
1193         if (!porigin->file.ptr && origin->file.ptr) {
1194                 /* Steal its file */
1195                 porigin->file = origin->file;
1196                 origin->file.ptr = NULL;
1197         }
1198         for (e = sb->ent; e; e = e->next) {
1199                 if (!same_suspect(e->suspect, origin))
1200                         continue;
1201                 origin_incref(porigin);
1202                 origin_decref(e->suspect);
1203                 e->suspect = porigin;
1204         }
1205 }
1206
1207 /*
1208  * We pass blame from the current commit to its parents.  We keep saying
1209  * "parent" (and "porigin"), but what we mean is to find scapegoat to
1210  * exonerate ourselves.
1211  */
1212 static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit)
1213 {
1214         if (!reverse)
1215                 return commit->parents;
1216         return lookup_decoration(&revs->children, &commit->object);
1217 }
1218
1219 static int num_scapegoats(struct rev_info *revs, struct commit *commit)
1220 {
1221         int cnt;
1222         struct commit_list *l = first_scapegoat(revs, commit);
1223         for (cnt = 0; l; l = l->next)
1224                 cnt++;
1225         return cnt;
1226 }
1227
1228 #define MAXSG 16
1229
1230 static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
1231 {
1232         struct rev_info *revs = sb->revs;
1233         int i, pass, num_sg;
1234         struct commit *commit = origin->commit;
1235         struct commit_list *sg;
1236         struct origin *sg_buf[MAXSG];
1237         struct origin *porigin, **sg_origin = sg_buf;
1238
1239         num_sg = num_scapegoats(revs, commit);
1240         if (!num_sg)
1241                 goto finish;
1242         else if (num_sg < ARRAY_SIZE(sg_buf))
1243                 memset(sg_buf, 0, sizeof(sg_buf));
1244         else
1245                 sg_origin = xcalloc(num_sg, sizeof(*sg_origin));
1246
1247         /*
1248          * The first pass looks for unrenamed path to optimize for
1249          * common cases, then we look for renames in the second pass.
1250          */
1251         for (pass = 0; pass < 2; pass++) {
1252                 struct origin *(*find)(struct scoreboard *,
1253                                        struct commit *, struct origin *);
1254                 find = pass ? find_rename : find_origin;
1255
1256                 for (i = 0, sg = first_scapegoat(revs, commit);
1257                      i < num_sg && sg;
1258                      sg = sg->next, i++) {
1259                         struct commit *p = sg->item;
1260                         int j, same;
1261
1262                         if (sg_origin[i])
1263                                 continue;
1264                         if (parse_commit(p))
1265                                 continue;
1266                         porigin = find(sb, p, origin);
1267                         if (!porigin)
1268                                 continue;
1269                         if (!hashcmp(porigin->blob_sha1, origin->blob_sha1)) {
1270                                 pass_whole_blame(sb, origin, porigin);
1271                                 origin_decref(porigin);
1272                                 goto finish;
1273                         }
1274                         for (j = same = 0; j < i; j++)
1275                                 if (sg_origin[j] &&
1276                                     !hashcmp(sg_origin[j]->blob_sha1,
1277                                              porigin->blob_sha1)) {
1278                                         same = 1;
1279                                         break;
1280                                 }
1281                         if (!same)
1282                                 sg_origin[i] = porigin;
1283                         else
1284                                 origin_decref(porigin);
1285                 }
1286         }
1287
1288         num_commits++;
1289         for (i = 0, sg = first_scapegoat(revs, commit);
1290              i < num_sg && sg;
1291              sg = sg->next, i++) {
1292                 struct origin *porigin = sg_origin[i];
1293                 if (!porigin)
1294                         continue;
1295                 if (pass_blame_to_parent(sb, origin, porigin))
1296                         goto finish;
1297         }
1298
1299         /*
1300          * Optionally find moves in parents' files.
1301          */
1302         if (opt & PICKAXE_BLAME_MOVE)
1303                 for (i = 0, sg = first_scapegoat(revs, commit);
1304                      i < num_sg && sg;
1305                      sg = sg->next, i++) {
1306                         struct origin *porigin = sg_origin[i];
1307                         if (!porigin)
1308                                 continue;
1309                         if (find_move_in_parent(sb, origin, porigin))
1310                                 goto finish;
1311                 }
1312
1313         /*
1314          * Optionally find copies from parents' files.
1315          */
1316         if (opt & PICKAXE_BLAME_COPY)
1317                 for (i = 0, sg = first_scapegoat(revs, commit);
1318                      i < num_sg && sg;
1319                      sg = sg->next, i++) {
1320                         struct origin *porigin = sg_origin[i];
1321                         if (find_copy_in_parent(sb, origin, sg->item,
1322                                                 porigin, opt))
1323                                 goto finish;
1324                 }
1325
1326  finish:
1327         for (i = 0; i < num_sg; i++) {
1328                 if (sg_origin[i]) {
1329                         drop_origin_blob(sg_origin[i]);
1330                         origin_decref(sg_origin[i]);
1331                 }
1332         }
1333         drop_origin_blob(origin);
1334         if (sg_buf != sg_origin)
1335                 free(sg_origin);
1336 }
1337
1338 /*
1339  * Information on commits, used for output.
1340  */
1341 struct commit_info
1342 {
1343         const char *author;
1344         const char *author_mail;
1345         unsigned long author_time;
1346         const char *author_tz;
1347
1348         /* filled only when asked for details */
1349         const char *committer;
1350         const char *committer_mail;
1351         unsigned long committer_time;
1352         const char *committer_tz;
1353
1354         const char *summary;
1355 };
1356
1357 /*
1358  * Parse author/committer line in the commit object buffer
1359  */
1360 static void get_ac_line(const char *inbuf, const char *what,
1361                         int bufsz, char *person, const char **mail,
1362                         unsigned long *time, const char **tz)
1363 {
1364         int len, tzlen, maillen;
1365         char *tmp, *endp, *timepos;
1366
1367         tmp = strstr(inbuf, what);
1368         if (!tmp)
1369                 goto error_out;
1370         tmp += strlen(what);
1371         endp = strchr(tmp, '\n');
1372         if (!endp)
1373                 len = strlen(tmp);
1374         else
1375                 len = endp - tmp;
1376         if (bufsz <= len) {
1377         error_out:
1378                 /* Ugh */
1379                 *mail = *tz = "(unknown)";
1380                 *time = 0;
1381                 return;
1382         }
1383         memcpy(person, tmp, len);
1384
1385         tmp = person;
1386         tmp += len;
1387         *tmp = 0;
1388         while (*tmp != ' ')
1389                 tmp--;
1390         *tz = tmp+1;
1391         tzlen = (person+len)-(tmp+1);
1392
1393         *tmp = 0;
1394         while (*tmp != ' ')
1395                 tmp--;
1396         *time = strtoul(tmp, NULL, 10);
1397         timepos = tmp;
1398
1399         *tmp = 0;
1400         while (*tmp != ' ')
1401                 tmp--;
1402         *mail = tmp + 1;
1403         *tmp = 0;
1404         maillen = timepos - tmp;
1405
1406         if (!mailmap.nr)
1407                 return;
1408
1409         /*
1410          * mailmap expansion may make the name longer.
1411          * make room by pushing stuff down.
1412          */
1413         tmp = person + bufsz - (tzlen + 1);
1414         memmove(tmp, *tz, tzlen);
1415         tmp[tzlen] = 0;
1416         *tz = tmp;
1417
1418         tmp = tmp - (maillen + 1);
1419         memmove(tmp, *mail, maillen);
1420         tmp[maillen] = 0;
1421         *mail = tmp;
1422
1423         /*
1424          * Now, convert e-mail using mailmap
1425          */
1426         map_email(&mailmap, tmp + 1, person, tmp-person-1);
1427 }
1428
1429 static void get_commit_info(struct commit *commit,
1430                             struct commit_info *ret,
1431                             int detailed)
1432 {
1433         int len;
1434         char *tmp, *endp;
1435         static char author_buf[1024];
1436         static char committer_buf[1024];
1437         static char summary_buf[1024];
1438
1439         /*
1440          * We've operated without save_commit_buffer, so
1441          * we now need to populate them for output.
1442          */
1443         if (!commit->buffer) {
1444                 enum object_type type;
1445                 unsigned long size;
1446                 commit->buffer =
1447                         read_sha1_file(commit->object.sha1, &type, &size);
1448                 if (!commit->buffer)
1449                         die("Cannot read commit %s",
1450                             sha1_to_hex(commit->object.sha1));
1451         }
1452         ret->author = author_buf;
1453         get_ac_line(commit->buffer, "\nauthor ",
1454                     sizeof(author_buf), author_buf, &ret->author_mail,
1455                     &ret->author_time, &ret->author_tz);
1456
1457         if (!detailed)
1458                 return;
1459
1460         ret->committer = committer_buf;
1461         get_ac_line(commit->buffer, "\ncommitter ",
1462                     sizeof(committer_buf), committer_buf, &ret->committer_mail,
1463                     &ret->committer_time, &ret->committer_tz);
1464
1465         ret->summary = summary_buf;
1466         tmp = strstr(commit->buffer, "\n\n");
1467         if (!tmp) {
1468         error_out:
1469                 sprintf(summary_buf, "(%s)", sha1_to_hex(commit->object.sha1));
1470                 return;
1471         }
1472         tmp += 2;
1473         endp = strchr(tmp, '\n');
1474         if (!endp)
1475                 endp = tmp + strlen(tmp);
1476         len = endp - tmp;
1477         if (len >= sizeof(summary_buf) || len == 0)
1478                 goto error_out;
1479         memcpy(summary_buf, tmp, len);
1480         summary_buf[len] = 0;
1481 }
1482
1483 /*
1484  * To allow LF and other nonportable characters in pathnames,
1485  * they are c-style quoted as needed.
1486  */
1487 static void write_filename_info(const char *path)
1488 {
1489         printf("filename ");
1490         write_name_quoted(path, stdout, '\n');
1491 }
1492
1493 /*
1494  * The blame_entry is found to be guilty for the range.  Mark it
1495  * as such, and show it in incremental output.
1496  */
1497 static void found_guilty_entry(struct blame_entry *ent)
1498 {
1499         if (ent->guilty)
1500                 return;
1501         ent->guilty = 1;
1502         if (incremental) {
1503                 struct origin *suspect = ent->suspect;
1504
1505                 printf("%s %d %d %d\n",
1506                        sha1_to_hex(suspect->commit->object.sha1),
1507                        ent->s_lno + 1, ent->lno + 1, ent->num_lines);
1508                 if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
1509                         struct commit_info ci;
1510                         suspect->commit->object.flags |= METAINFO_SHOWN;
1511                         get_commit_info(suspect->commit, &ci, 1);
1512                         printf("author %s\n", ci.author);
1513                         printf("author-mail %s\n", ci.author_mail);
1514                         printf("author-time %lu\n", ci.author_time);
1515                         printf("author-tz %s\n", ci.author_tz);
1516                         printf("committer %s\n", ci.committer);
1517                         printf("committer-mail %s\n", ci.committer_mail);
1518                         printf("committer-time %lu\n", ci.committer_time);
1519                         printf("committer-tz %s\n", ci.committer_tz);
1520                         printf("summary %s\n", ci.summary);
1521                         if (suspect->commit->object.flags & UNINTERESTING)
1522                                 printf("boundary\n");
1523                 }
1524                 write_filename_info(suspect->path);
1525                 maybe_flush_or_die(stdout, "stdout");
1526         }
1527 }
1528
1529 /*
1530  * The main loop -- while the scoreboard has lines whose true origin
1531  * is still unknown, pick one blame_entry, and allow its current
1532  * suspect to pass blames to its parents.
1533  */
1534 static void assign_blame(struct scoreboard *sb, int opt)
1535 {
1536         struct rev_info *revs = sb->revs;
1537
1538         while (1) {
1539                 struct blame_entry *ent;
1540                 struct commit *commit;
1541                 struct origin *suspect = NULL;
1542
1543                 /* find one suspect to break down */
1544                 for (ent = sb->ent; !suspect && ent; ent = ent->next)
1545                         if (!ent->guilty)
1546                                 suspect = ent->suspect;
1547                 if (!suspect)
1548                         return; /* all done */
1549
1550                 /*
1551                  * We will use this suspect later in the loop,
1552                  * so hold onto it in the meantime.
1553                  */
1554                 origin_incref(suspect);
1555                 commit = suspect->commit;
1556                 if (!commit->object.parsed)
1557                         parse_commit(commit);
1558                 if (reverse ||
1559                     (!(commit->object.flags & UNINTERESTING) &&
1560                      !(revs->max_age != -1 && commit->date < revs->max_age)))
1561                         pass_blame(sb, suspect, opt);
1562                 else {
1563                         commit->object.flags |= UNINTERESTING;
1564                         if (commit->object.parsed)
1565                                 mark_parents_uninteresting(commit);
1566                 }
1567                 /* treat root commit as boundary */
1568                 if (!commit->parents && !show_root)
1569                         commit->object.flags |= UNINTERESTING;
1570
1571                 /* Take responsibility for the remaining entries */
1572                 for (ent = sb->ent; ent; ent = ent->next)
1573                         if (same_suspect(ent->suspect, suspect))
1574                                 found_guilty_entry(ent);
1575                 origin_decref(suspect);
1576
1577                 if (DEBUG) /* sanity */
1578                         sanity_check_refcnt(sb);
1579         }
1580 }
1581
1582 static const char *format_time(unsigned long time, const char *tz_str,
1583                                int show_raw_time)
1584 {
1585         static char time_buf[128];
1586         time_t t = time;
1587         int minutes, tz;
1588         struct tm *tm;
1589
1590         if (show_raw_time) {
1591                 sprintf(time_buf, "%lu %s", time, tz_str);
1592                 return time_buf;
1593         }
1594
1595         tz = atoi(tz_str);
1596         minutes = tz < 0 ? -tz : tz;
1597         minutes = (minutes / 100)*60 + (minutes % 100);
1598         minutes = tz < 0 ? -minutes : minutes;
1599         t = time + minutes * 60;
1600         tm = gmtime(&t);
1601
1602         strftime(time_buf, sizeof(time_buf), "%Y-%m-%d %H:%M:%S ", tm);
1603         strcat(time_buf, tz_str);
1604         return time_buf;
1605 }
1606
1607 #define OUTPUT_ANNOTATE_COMPAT  001
1608 #define OUTPUT_LONG_OBJECT_NAME 002
1609 #define OUTPUT_RAW_TIMESTAMP    004
1610 #define OUTPUT_PORCELAIN        010
1611 #define OUTPUT_SHOW_NAME        020
1612 #define OUTPUT_SHOW_NUMBER      040
1613 #define OUTPUT_SHOW_SCORE      0100
1614 #define OUTPUT_NO_AUTHOR       0200
1615
1616 static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent)
1617 {
1618         int cnt;
1619         const char *cp;
1620         struct origin *suspect = ent->suspect;
1621         char hex[41];
1622
1623         strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
1624         printf("%s%c%d %d %d\n",
1625                hex,
1626                ent->guilty ? ' ' : '*', // purely for debugging
1627                ent->s_lno + 1,
1628                ent->lno + 1,
1629                ent->num_lines);
1630         if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
1631                 struct commit_info ci;
1632                 suspect->commit->object.flags |= METAINFO_SHOWN;
1633                 get_commit_info(suspect->commit, &ci, 1);
1634                 printf("author %s\n", ci.author);
1635                 printf("author-mail %s\n", ci.author_mail);
1636                 printf("author-time %lu\n", ci.author_time);
1637                 printf("author-tz %s\n", ci.author_tz);
1638                 printf("committer %s\n", ci.committer);
1639                 printf("committer-mail %s\n", ci.committer_mail);
1640                 printf("committer-time %lu\n", ci.committer_time);
1641                 printf("committer-tz %s\n", ci.committer_tz);
1642                 write_filename_info(suspect->path);
1643                 printf("summary %s\n", ci.summary);
1644                 if (suspect->commit->object.flags & UNINTERESTING)
1645                         printf("boundary\n");
1646         }
1647         else if (suspect->commit->object.flags & MORE_THAN_ONE_PATH)
1648                 write_filename_info(suspect->path);
1649
1650         cp = nth_line(sb, ent->lno);
1651         for (cnt = 0; cnt < ent->num_lines; cnt++) {
1652                 char ch;
1653                 if (cnt)
1654                         printf("%s %d %d\n", hex,
1655                                ent->s_lno + 1 + cnt,
1656                                ent->lno + 1 + cnt);
1657                 putchar('\t');
1658                 do {
1659                         ch = *cp++;
1660                         putchar(ch);
1661                 } while (ch != '\n' &&
1662                          cp < sb->final_buf + sb->final_buf_size);
1663         }
1664 }
1665
1666 static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
1667 {
1668         int cnt;
1669         const char *cp;
1670         struct origin *suspect = ent->suspect;
1671         struct commit_info ci;
1672         char hex[41];
1673         int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
1674
1675         get_commit_info(suspect->commit, &ci, 1);
1676         strcpy(hex, sha1_to_hex(suspect->commit->object.sha1));
1677
1678         cp = nth_line(sb, ent->lno);
1679         for (cnt = 0; cnt < ent->num_lines; cnt++) {
1680                 char ch;
1681                 int length = (opt & OUTPUT_LONG_OBJECT_NAME) ? 40 : 8;
1682
1683                 if (suspect->commit->object.flags & UNINTERESTING) {
1684                         if (blank_boundary)
1685                                 memset(hex, ' ', length);
1686                         else if (!(opt & OUTPUT_ANNOTATE_COMPAT)) {
1687                                 length--;
1688                                 putchar('^');
1689                         }
1690                 }
1691
1692                 printf("%.*s", length, hex);
1693                 if (opt & OUTPUT_ANNOTATE_COMPAT)
1694                         printf("\t(%10s\t%10s\t%d)", ci.author,
1695                                format_time(ci.author_time, ci.author_tz,
1696                                            show_raw_time),
1697                                ent->lno + 1 + cnt);
1698                 else {
1699                         if (opt & OUTPUT_SHOW_SCORE)
1700                                 printf(" %*d %02d",
1701                                        max_score_digits, ent->score,
1702                                        ent->suspect->refcnt);
1703                         if (opt & OUTPUT_SHOW_NAME)
1704                                 printf(" %-*.*s", longest_file, longest_file,
1705                                        suspect->path);
1706                         if (opt & OUTPUT_SHOW_NUMBER)
1707                                 printf(" %*d", max_orig_digits,
1708                                        ent->s_lno + 1 + cnt);
1709
1710                         if (!(opt & OUTPUT_NO_AUTHOR))
1711                                 printf(" (%-*.*s %10s",
1712                                        longest_author, longest_author,
1713                                        ci.author,
1714                                        format_time(ci.author_time,
1715                                                    ci.author_tz,
1716                                                    show_raw_time));
1717                         printf(" %*d) ",
1718                                max_digits, ent->lno + 1 + cnt);
1719                 }
1720                 do {
1721                         ch = *cp++;
1722                         putchar(ch);
1723                 } while (ch != '\n' &&
1724                          cp < sb->final_buf + sb->final_buf_size);
1725         }
1726 }
1727
1728 static void output(struct scoreboard *sb, int option)
1729 {
1730         struct blame_entry *ent;
1731
1732         if (option & OUTPUT_PORCELAIN) {
1733                 for (ent = sb->ent; ent; ent = ent->next) {
1734                         struct blame_entry *oth;
1735                         struct origin *suspect = ent->suspect;
1736                         struct commit *commit = suspect->commit;
1737                         if (commit->object.flags & MORE_THAN_ONE_PATH)
1738                                 continue;
1739                         for (oth = ent->next; oth; oth = oth->next) {
1740                                 if ((oth->suspect->commit != commit) ||
1741                                     !strcmp(oth->suspect->path, suspect->path))
1742                                         continue;
1743                                 commit->object.flags |= MORE_THAN_ONE_PATH;
1744                                 break;
1745                         }
1746                 }
1747         }
1748
1749         for (ent = sb->ent; ent; ent = ent->next) {
1750                 if (option & OUTPUT_PORCELAIN)
1751                         emit_porcelain(sb, ent);
1752                 else {
1753                         emit_other(sb, ent, option);
1754                 }
1755         }
1756 }
1757
1758 /*
1759  * To allow quick access to the contents of nth line in the
1760  * final image, prepare an index in the scoreboard.
1761  */
1762 static int prepare_lines(struct scoreboard *sb)
1763 {
1764         const char *buf = sb->final_buf;
1765         unsigned long len = sb->final_buf_size;
1766         int num = 0, incomplete = 0, bol = 1;
1767
1768         if (len && buf[len-1] != '\n')
1769                 incomplete++; /* incomplete line at the end */
1770         while (len--) {
1771                 if (bol) {
1772                         sb->lineno = xrealloc(sb->lineno,
1773                                               sizeof(int* ) * (num + 1));
1774                         sb->lineno[num] = buf - sb->final_buf;
1775                         bol = 0;
1776                 }
1777                 if (*buf++ == '\n') {
1778                         num++;
1779                         bol = 1;
1780                 }
1781         }
1782         sb->lineno = xrealloc(sb->lineno,
1783                               sizeof(int* ) * (num + incomplete + 1));
1784         sb->lineno[num + incomplete] = buf - sb->final_buf;
1785         sb->num_lines = num + incomplete;
1786         return sb->num_lines;
1787 }
1788
1789 /*
1790  * Add phony grafts for use with -S; this is primarily to
1791  * support git's cvsserver that wants to give a linear history
1792  * to its clients.
1793  */
1794 static int read_ancestry(const char *graft_file)
1795 {
1796         FILE *fp = fopen(graft_file, "r");
1797         char buf[1024];
1798         if (!fp)
1799                 return -1;
1800         while (fgets(buf, sizeof(buf), fp)) {
1801                 /* The format is just "Commit Parent1 Parent2 ...\n" */
1802                 int len = strlen(buf);
1803                 struct commit_graft *graft = read_graft_line(buf, len);
1804                 if (graft)
1805                         register_commit_graft(graft, 0);
1806         }
1807         fclose(fp);
1808         return 0;
1809 }
1810
1811 /*
1812  * How many columns do we need to show line numbers in decimal?
1813  */
1814 static int lineno_width(int lines)
1815 {
1816         int i, width;
1817
1818         for (width = 1, i = 10; i <= lines + 1; width++)
1819                 i *= 10;
1820         return width;
1821 }
1822
1823 /*
1824  * How many columns do we need to show line numbers, authors,
1825  * and filenames?
1826  */
1827 static void find_alignment(struct scoreboard *sb, int *option)
1828 {
1829         int longest_src_lines = 0;
1830         int longest_dst_lines = 0;
1831         unsigned largest_score = 0;
1832         struct blame_entry *e;
1833
1834         for (e = sb->ent; e; e = e->next) {
1835                 struct origin *suspect = e->suspect;
1836                 struct commit_info ci;
1837                 int num;
1838
1839                 if (strcmp(suspect->path, sb->path))
1840                         *option |= OUTPUT_SHOW_NAME;
1841                 num = strlen(suspect->path);
1842                 if (longest_file < num)
1843                         longest_file = num;
1844                 if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
1845                         suspect->commit->object.flags |= METAINFO_SHOWN;
1846                         get_commit_info(suspect->commit, &ci, 1);
1847                         num = strlen(ci.author);
1848                         if (longest_author < num)
1849                                 longest_author = num;
1850                 }
1851                 num = e->s_lno + e->num_lines;
1852                 if (longest_src_lines < num)
1853                         longest_src_lines = num;
1854                 num = e->lno + e->num_lines;
1855                 if (longest_dst_lines < num)
1856                         longest_dst_lines = num;
1857                 if (largest_score < ent_score(sb, e))
1858                         largest_score = ent_score(sb, e);
1859         }
1860         max_orig_digits = lineno_width(longest_src_lines);
1861         max_digits = lineno_width(longest_dst_lines);
1862         max_score_digits = lineno_width(largest_score);
1863 }
1864
1865 /*
1866  * For debugging -- origin is refcounted, and this asserts that
1867  * we do not underflow.
1868  */
1869 static void sanity_check_refcnt(struct scoreboard *sb)
1870 {
1871         int baa = 0;
1872         struct blame_entry *ent;
1873
1874         for (ent = sb->ent; ent; ent = ent->next) {
1875                 /* Nobody should have zero or negative refcnt */
1876                 if (ent->suspect->refcnt <= 0) {
1877                         fprintf(stderr, "%s in %s has negative refcnt %d\n",
1878                                 ent->suspect->path,
1879                                 sha1_to_hex(ent->suspect->commit->object.sha1),
1880                                 ent->suspect->refcnt);
1881                         baa = 1;
1882                 }
1883         }
1884         for (ent = sb->ent; ent; ent = ent->next) {
1885                 /* Mark the ones that haven't been checked */
1886                 if (0 < ent->suspect->refcnt)
1887                         ent->suspect->refcnt = -ent->suspect->refcnt;
1888         }
1889         for (ent = sb->ent; ent; ent = ent->next) {
1890                 /*
1891                  * ... then pick each and see if they have the the
1892                  * correct refcnt.
1893                  */
1894                 int found;
1895                 struct blame_entry *e;
1896                 struct origin *suspect = ent->suspect;
1897
1898                 if (0 < suspect->refcnt)
1899                         continue;
1900                 suspect->refcnt = -suspect->refcnt; /* Unmark */
1901                 for (found = 0, e = sb->ent; e; e = e->next) {
1902                         if (e->suspect != suspect)
1903                                 continue;
1904                         found++;
1905                 }
1906                 if (suspect->refcnt != found) {
1907                         fprintf(stderr, "%s in %s has refcnt %d, not %d\n",
1908                                 ent->suspect->path,
1909                                 sha1_to_hex(ent->suspect->commit->object.sha1),
1910                                 ent->suspect->refcnt, found);
1911                         baa = 2;
1912                 }
1913         }
1914         if (baa) {
1915                 int opt = 0160;
1916                 find_alignment(sb, &opt);
1917                 output(sb, opt);
1918                 die("Baa %d!", baa);
1919         }
1920 }
1921
1922 /*
1923  * Used for the command line parsing; check if the path exists
1924  * in the working tree.
1925  */
1926 static int has_string_in_work_tree(const char *path)
1927 {
1928         struct stat st;
1929         return !lstat(path, &st);
1930 }
1931
1932 static unsigned parse_score(const char *arg)
1933 {
1934         char *end;
1935         unsigned long score = strtoul(arg, &end, 10);
1936         if (*end)
1937                 return 0;
1938         return score;
1939 }
1940
1941 static const char *add_prefix(const char *prefix, const char *path)
1942 {
1943         return prefix_path(prefix, prefix ? strlen(prefix) : 0, path);
1944 }
1945
1946 /*
1947  * Parsing of (comma separated) one item in the -L option
1948  */
1949 static const char *parse_loc(const char *spec,
1950                              struct scoreboard *sb, long lno,
1951                              long begin, long *ret)
1952 {
1953         char *term;
1954         const char *line;
1955         long num;
1956         int reg_error;
1957         regex_t regexp;
1958         regmatch_t match[1];
1959
1960         /* Allow "-L <something>,+20" to mean starting at <something>
1961          * for 20 lines, or "-L <something>,-5" for 5 lines ending at
1962          * <something>.
1963          */
1964         if (1 < begin && (spec[0] == '+' || spec[0] == '-')) {
1965                 num = strtol(spec + 1, &term, 10);
1966                 if (term != spec + 1) {
1967                         if (spec[0] == '-')
1968                                 num = 0 - num;
1969                         if (0 < num)
1970                                 *ret = begin + num - 2;
1971                         else if (!num)
1972                                 *ret = begin;
1973                         else
1974                                 *ret = begin + num;
1975                         return term;
1976                 }
1977                 return spec;
1978         }
1979         num = strtol(spec, &term, 10);
1980         if (term != spec) {
1981                 *ret = num;
1982                 return term;
1983         }
1984         if (spec[0] != '/')
1985                 return spec;
1986
1987         /* it could be a regexp of form /.../ */
1988         for (term = (char*) spec + 1; *term && *term != '/'; term++) {
1989                 if (*term == '\\')
1990                         term++;
1991         }
1992         if (*term != '/')
1993                 return spec;
1994
1995         /* try [spec+1 .. term-1] as regexp */
1996         *term = 0;
1997         begin--; /* input is in human terms */
1998         line = nth_line(sb, begin);
1999
2000         if (!(reg_error = regcomp(&regexp, spec + 1, REG_NEWLINE)) &&
2001             !(reg_error = regexec(&regexp, line, 1, match, 0))) {
2002                 const char *cp = line + match[0].rm_so;
2003                 const char *nline;
2004
2005                 while (begin++ < lno) {
2006                         nline = nth_line(sb, begin);
2007                         if (line <= cp && cp < nline)
2008                                 break;
2009                         line = nline;
2010                 }
2011                 *ret = begin;
2012                 regfree(&regexp);
2013                 *term++ = '/';
2014                 return term;
2015         }
2016         else {
2017                 char errbuf[1024];
2018                 regerror(reg_error, &regexp, errbuf, 1024);
2019                 die("-L parameter '%s': %s", spec + 1, errbuf);
2020         }
2021 }
2022
2023 /*
2024  * Parsing of -L option
2025  */
2026 static void prepare_blame_range(struct scoreboard *sb,
2027                                 const char *bottomtop,
2028                                 long lno,
2029                                 long *bottom, long *top)
2030 {
2031         const char *term;
2032
2033         term = parse_loc(bottomtop, sb, lno, 1, bottom);
2034         if (*term == ',') {
2035                 term = parse_loc(term + 1, sb, lno, *bottom + 1, top);
2036                 if (*term)
2037                         usage(blame_usage);
2038         }
2039         if (*term)
2040                 usage(blame_usage);
2041 }
2042
2043 static int git_blame_config(const char *var, const char *value, void *cb)
2044 {
2045         if (!strcmp(var, "blame.showroot")) {
2046                 show_root = git_config_bool(var, value);
2047                 return 0;
2048         }
2049         if (!strcmp(var, "blame.blankboundary")) {
2050                 blank_boundary = git_config_bool(var, value);
2051                 return 0;
2052         }
2053         return git_default_config(var, value, cb);
2054 }
2055
2056 /*
2057  * Prepare a dummy commit that represents the work tree (or staged) item.
2058  * Note that annotating work tree item never works in the reverse.
2059  */
2060 static struct commit *fake_working_tree_commit(const char *path, const char *contents_from)
2061 {
2062         struct commit *commit;
2063         struct origin *origin;
2064         unsigned char head_sha1[20];
2065         struct strbuf buf = STRBUF_INIT;
2066         const char *ident;
2067         time_t now;
2068         int size, len;
2069         struct cache_entry *ce;
2070         unsigned mode;
2071
2072         if (get_sha1("HEAD", head_sha1))
2073                 die("No such ref: HEAD");
2074
2075         time(&now);
2076         commit = xcalloc(1, sizeof(*commit));
2077         commit->parents = xcalloc(1, sizeof(*commit->parents));
2078         commit->parents->item = lookup_commit_reference(head_sha1);
2079         commit->object.parsed = 1;
2080         commit->date = now;
2081         commit->object.type = OBJ_COMMIT;
2082
2083         origin = make_origin(commit, path);
2084
2085         if (!contents_from || strcmp("-", contents_from)) {
2086                 struct stat st;
2087                 const char *read_from;
2088                 unsigned long fin_size;
2089
2090                 if (contents_from) {
2091                         if (stat(contents_from, &st) < 0)
2092                                 die("Cannot stat %s", contents_from);
2093                         read_from = contents_from;
2094                 }
2095                 else {
2096                         if (lstat(path, &st) < 0)
2097                                 die("Cannot lstat %s", path);
2098                         read_from = path;
2099                 }
2100                 fin_size = xsize_t(st.st_size);
2101                 mode = canon_mode(st.st_mode);
2102                 switch (st.st_mode & S_IFMT) {
2103                 case S_IFREG:
2104                         if (strbuf_read_file(&buf, read_from, st.st_size) != st.st_size)
2105                                 die("cannot open or read %s", read_from);
2106                         break;
2107                 case S_IFLNK:
2108                         if (readlink(read_from, buf.buf, buf.alloc) != fin_size)
2109                                 die("cannot readlink %s", read_from);
2110                         buf.len = fin_size;
2111                         break;
2112                 default:
2113                         die("unsupported file type %s", read_from);
2114                 }
2115         }
2116         else {
2117                 /* Reading from stdin */
2118                 contents_from = "standard input";
2119                 mode = 0;
2120                 if (strbuf_read(&buf, 0, 0) < 0)
2121                         die("read error %s from stdin", strerror(errno));
2122         }
2123         convert_to_git(path, buf.buf, buf.len, &buf, 0);
2124         origin->file.ptr = buf.buf;
2125         origin->file.size = buf.len;
2126         pretend_sha1_file(buf.buf, buf.len, OBJ_BLOB, origin->blob_sha1);
2127         commit->util = origin;
2128
2129         /*
2130          * Read the current index, replace the path entry with
2131          * origin->blob_sha1 without mucking with its mode or type
2132          * bits; we are not going to write this index out -- we just
2133          * want to run "diff-index --cached".
2134          */
2135         discard_cache();
2136         read_cache();
2137
2138         len = strlen(path);
2139         if (!mode) {
2140                 int pos = cache_name_pos(path, len);
2141                 if (0 <= pos)
2142                         mode = active_cache[pos]->ce_mode;
2143                 else
2144                         /* Let's not bother reading from HEAD tree */
2145                         mode = S_IFREG | 0644;
2146         }
2147         size = cache_entry_size(len);
2148         ce = xcalloc(1, size);
2149         hashcpy(ce->sha1, origin->blob_sha1);
2150         memcpy(ce->name, path, len);
2151         ce->ce_flags = create_ce_flags(len, 0);
2152         ce->ce_mode = create_ce_mode(mode);
2153         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
2154
2155         /*
2156          * We are not going to write this out, so this does not matter
2157          * right now, but someday we might optimize diff-index --cached
2158          * with cache-tree information.
2159          */
2160         cache_tree_invalidate_path(active_cache_tree, path);
2161
2162         commit->buffer = xmalloc(400);
2163         ident = fmt_ident("Not Committed Yet", "not.committed.yet", NULL, 0);
2164         snprintf(commit->buffer, 400,
2165                 "tree 0000000000000000000000000000000000000000\n"
2166                 "parent %s\n"
2167                 "author %s\n"
2168                 "committer %s\n\n"
2169                 "Version of %s from %s\n",
2170                 sha1_to_hex(head_sha1),
2171                 ident, ident, path, contents_from ? contents_from : path);
2172         return commit;
2173 }
2174
2175 static const char *prepare_final(struct scoreboard *sb)
2176 {
2177         int i;
2178         const char *final_commit_name = NULL;
2179         struct rev_info *revs = sb->revs;
2180
2181         /*
2182          * There must be one and only one positive commit in the
2183          * revs->pending array.
2184          */
2185         for (i = 0; i < revs->pending.nr; i++) {
2186                 struct object *obj = revs->pending.objects[i].item;
2187                 if (obj->flags & UNINTERESTING)
2188                         continue;
2189                 while (obj->type == OBJ_TAG)
2190                         obj = deref_tag(obj, NULL, 0);
2191                 if (obj->type != OBJ_COMMIT)
2192                         die("Non commit %s?", revs->pending.objects[i].name);
2193                 if (sb->final)
2194                         die("More than one commit to dig from %s and %s?",
2195                             revs->pending.objects[i].name,
2196                             final_commit_name);
2197                 sb->final = (struct commit *) obj;
2198                 final_commit_name = revs->pending.objects[i].name;
2199         }
2200         return final_commit_name;
2201 }
2202
2203 static const char *prepare_initial(struct scoreboard *sb)
2204 {
2205         int i;
2206         const char *final_commit_name = NULL;
2207         struct rev_info *revs = sb->revs;
2208
2209         /*
2210          * There must be one and only one negative commit, and it must be
2211          * the boundary.
2212          */
2213         for (i = 0; i < revs->pending.nr; i++) {
2214                 struct object *obj = revs->pending.objects[i].item;
2215                 if (!(obj->flags & UNINTERESTING))
2216                         continue;
2217                 while (obj->type == OBJ_TAG)
2218                         obj = deref_tag(obj, NULL, 0);
2219                 if (obj->type != OBJ_COMMIT)
2220                         die("Non commit %s?", revs->pending.objects[i].name);
2221                 if (sb->final)
2222                         die("More than one commit to dig down to %s and %s?",
2223                             revs->pending.objects[i].name,
2224                             final_commit_name);
2225                 sb->final = (struct commit *) obj;
2226                 final_commit_name = revs->pending.objects[i].name;
2227         }
2228         if (!final_commit_name)
2229                 die("No commit to dig down to?");
2230         return final_commit_name;
2231 }
2232
2233 static int blame_copy_callback(const struct option *option, const char *arg, int unset)
2234 {
2235         int *opt = option->value;
2236
2237         /*
2238          * -C enables copy from removed files;
2239          * -C -C enables copy from existing files, but only
2240          *       when blaming a new file;
2241          * -C -C -C enables copy from existing files for
2242          *          everybody
2243          */
2244         if (*opt & PICKAXE_BLAME_COPY_HARDER)
2245                 *opt |= PICKAXE_BLAME_COPY_HARDEST;
2246         if (*opt & PICKAXE_BLAME_COPY)
2247                 *opt |= PICKAXE_BLAME_COPY_HARDER;
2248         *opt |= PICKAXE_BLAME_COPY | PICKAXE_BLAME_MOVE;
2249
2250         if (arg)
2251                 blame_copy_score = parse_score(arg);
2252         return 0;
2253 }
2254
2255 static int blame_move_callback(const struct option *option, const char *arg, int unset)
2256 {
2257         int *opt = option->value;
2258
2259         *opt |= PICKAXE_BLAME_MOVE;
2260
2261         if (arg)
2262                 blame_move_score = parse_score(arg);
2263         return 0;
2264 }
2265
2266 static int blame_bottomtop_callback(const struct option *option, const char *arg, int unset)
2267 {
2268         const char **bottomtop = option->value;
2269         if (!arg)
2270                 return -1;
2271         if (*bottomtop)
2272                 die("More than one '-L n,m' option given");
2273         *bottomtop = arg;
2274         return 0;
2275 }
2276
2277 int cmd_blame(int argc, const char **argv, const char *prefix)
2278 {
2279         struct rev_info revs;
2280         const char *path;
2281         struct scoreboard sb;
2282         struct origin *o;
2283         struct blame_entry *ent;
2284         long dashdash_pos, bottom, top, lno;
2285         const char *final_commit_name = NULL;
2286         enum object_type type;
2287
2288         static const char *bottomtop = NULL;
2289         static int output_option = 0, opt = 0;
2290         static int show_stats = 0;
2291         static const char *revs_file = NULL;
2292         static const char *contents_from = NULL;
2293         static const struct option options[] = {
2294                 OPT_BOOLEAN(0, "incremental", &incremental, "Show blame entries as we find them, incrementally"),
2295                 OPT_BOOLEAN('b', NULL, &blank_boundary, "Show blank SHA-1 for boundary commits (Default: off)"),
2296                 OPT_BOOLEAN(0, "root", &show_root, "Do not treat root commits as boundaries (Default: off)"),
2297                 OPT_BOOLEAN(0, "show-stats", &show_stats, "Show work cost statistics"),
2298                 OPT_BIT(0, "score-debug", &output_option, "Show output score for blame entries", OUTPUT_SHOW_SCORE),
2299                 OPT_BIT('f', "show-name", &output_option, "Show original filename (Default: auto)", OUTPUT_SHOW_NAME),
2300                 OPT_BIT('n', "show-number", &output_option, "Show original linenumber (Default: off)", OUTPUT_SHOW_NUMBER),
2301                 OPT_BIT('p', "porcelain", &output_option, "Show in a format designed for machine consumption", OUTPUT_PORCELAIN),
2302                 OPT_BIT('c', NULL, &output_option, "Use the same output mode as git-annotate (Default: off)", OUTPUT_ANNOTATE_COMPAT),
2303                 OPT_BIT('t', NULL, &output_option, "Show raw timestamp (Default: off)", OUTPUT_RAW_TIMESTAMP),
2304                 OPT_BIT('l', NULL, &output_option, "Show long commit SHA1 (Default: off)", OUTPUT_LONG_OBJECT_NAME),
2305                 OPT_BIT('s', NULL, &output_option, "Suppress author name and timestamp (Default: off)", OUTPUT_NO_AUTHOR),
2306                 OPT_BIT('w', NULL, &xdl_opts, "Ignore whitespace differences", XDF_IGNORE_WHITESPACE),
2307                 OPT_STRING('S', NULL, &revs_file, "file", "Use revisions from <file> instead of calling git-rev-list"),
2308                 OPT_STRING(0, "contents", &contents_from, "file", "Use <file>'s contents as the final image"),
2309                 { OPTION_CALLBACK, 'C', NULL, &opt, "score", "Find line copies within and across files", PARSE_OPT_OPTARG, blame_copy_callback },
2310                 { OPTION_CALLBACK, 'M', NULL, &opt, "score", "Find line movements within and across files", PARSE_OPT_OPTARG, blame_move_callback },
2311                 OPT_CALLBACK('L', NULL, &bottomtop, "n,m", "Process only line range n,m, counting from 1", blame_bottomtop_callback),
2312                 OPT_END()
2313         };
2314
2315         struct parse_opt_ctx_t ctx;
2316         int cmd_is_annotate = !strcmp(argv[0], "annotate");
2317
2318         git_config(git_blame_config, NULL);
2319         init_revisions(&revs, NULL);
2320         save_commit_buffer = 0;
2321         dashdash_pos = 0;
2322
2323         parse_options_start(&ctx, argc, argv, PARSE_OPT_KEEP_DASHDASH |
2324                             PARSE_OPT_KEEP_ARGV0);
2325         for (;;) {
2326                 switch (parse_options_step(&ctx, options, blame_opt_usage)) {
2327                 case PARSE_OPT_HELP:
2328                         exit(129);
2329                 case PARSE_OPT_DONE:
2330                         if (ctx.argv[0])
2331                                 dashdash_pos = ctx.cpidx;
2332                         goto parse_done;
2333                 }
2334
2335                 if (!strcmp(ctx.argv[0], "--reverse")) {
2336                         ctx.argv[0] = "--children";
2337                         reverse = 1;
2338                 }
2339                 parse_revision_opt(&revs, &ctx, options, blame_opt_usage);
2340         }
2341 parse_done:
2342         argc = parse_options_end(&ctx);
2343
2344         if (cmd_is_annotate)
2345                 output_option |= OUTPUT_ANNOTATE_COMPAT;
2346
2347         if (DIFF_OPT_TST(&revs.diffopt, FIND_COPIES_HARDER))
2348                 opt |= (PICKAXE_BLAME_COPY | PICKAXE_BLAME_MOVE |
2349                         PICKAXE_BLAME_COPY_HARDER);
2350
2351         if (!blame_move_score)
2352                 blame_move_score = BLAME_DEFAULT_MOVE_SCORE;
2353         if (!blame_copy_score)
2354                 blame_copy_score = BLAME_DEFAULT_COPY_SCORE;
2355
2356         /*
2357          * We have collected options unknown to us in argv[1..unk]
2358          * which are to be passed to revision machinery if we are
2359          * going to do the "bottom" processing.
2360          *
2361          * The remaining are:
2362          *
2363          * (1) if dashdash_pos != 0, its either
2364          *     "blame [revisions] -- <path>" or
2365          *     "blame -- <path> <rev>"
2366          *
2367          * (2) otherwise, its one of the two:
2368          *     "blame [revisions] <path>"
2369          *     "blame <path> <rev>"
2370          *
2371          * Note that we must strip out <path> from the arguments: we do not
2372          * want the path pruning but we may want "bottom" processing.
2373          */
2374         if (dashdash_pos) {
2375                 switch (argc - dashdash_pos - 1) {
2376                 case 2: /* (1b) */
2377                         if (argc != 4)
2378                                 usage_with_options(blame_opt_usage, options);
2379                         /* reorder for the new way: <rev> -- <path> */
2380                         argv[1] = argv[3];
2381                         argv[3] = argv[2];
2382                         argv[2] = "--";
2383                         /* FALLTHROUGH */
2384                 case 1: /* (1a) */
2385                         path = add_prefix(prefix, argv[--argc]);
2386                         argv[argc] = NULL;
2387                         break;
2388                 default:
2389                         usage_with_options(blame_opt_usage, options);
2390                 }
2391         } else {
2392                 if (argc < 2)
2393                         usage_with_options(blame_opt_usage, options);
2394                 path = add_prefix(prefix, argv[argc - 1]);
2395                 if (argc == 3 && !has_string_in_work_tree(path)) { /* (2b) */
2396                         path = add_prefix(prefix, argv[1]);
2397                         argv[1] = argv[2];
2398                 }
2399                 argv[argc - 1] = "--";
2400
2401                 setup_work_tree();
2402                 if (!has_string_in_work_tree(path))
2403                         die("cannot stat path %s: %s", path, strerror(errno));
2404         }
2405
2406         setup_revisions(argc, argv, &revs, NULL);
2407         memset(&sb, 0, sizeof(sb));
2408
2409         sb.revs = &revs;
2410         if (!reverse)
2411                 final_commit_name = prepare_final(&sb);
2412         else if (contents_from)
2413                 die("--contents and --children do not blend well.");
2414         else
2415                 final_commit_name = prepare_initial(&sb);
2416
2417         if (!sb.final) {
2418                 /*
2419                  * "--not A B -- path" without anything positive;
2420                  * do not default to HEAD, but use the working tree
2421                  * or "--contents".
2422                  */
2423                 setup_work_tree();
2424                 sb.final = fake_working_tree_commit(path, contents_from);
2425                 add_pending_object(&revs, &(sb.final->object), ":");
2426         }
2427         else if (contents_from)
2428                 die("Cannot use --contents with final commit object name");
2429
2430         /*
2431          * If we have bottom, this will mark the ancestors of the
2432          * bottom commits we would reach while traversing as
2433          * uninteresting.
2434          */
2435         if (prepare_revision_walk(&revs))
2436                 die("revision walk setup failed");
2437
2438         if (is_null_sha1(sb.final->object.sha1)) {
2439                 char *buf;
2440                 o = sb.final->util;
2441                 buf = xmalloc(o->file.size + 1);
2442                 memcpy(buf, o->file.ptr, o->file.size + 1);
2443                 sb.final_buf = buf;
2444                 sb.final_buf_size = o->file.size;
2445         }
2446         else {
2447                 o = get_origin(&sb, sb.final, path);
2448                 if (fill_blob_sha1(o))
2449                         die("no such path %s in %s", path, final_commit_name);
2450
2451                 sb.final_buf = read_sha1_file(o->blob_sha1, &type,
2452                                               &sb.final_buf_size);
2453                 if (!sb.final_buf)
2454                         die("Cannot read blob %s for path %s",
2455                             sha1_to_hex(o->blob_sha1),
2456                             path);
2457         }
2458         num_read_blob++;
2459         lno = prepare_lines(&sb);
2460
2461         bottom = top = 0;
2462         if (bottomtop)
2463                 prepare_blame_range(&sb, bottomtop, lno, &bottom, &top);
2464         if (bottom && top && top < bottom) {
2465                 long tmp;
2466                 tmp = top; top = bottom; bottom = tmp;
2467         }
2468         if (bottom < 1)
2469                 bottom = 1;
2470         if (top < 1)
2471                 top = lno;
2472         bottom--;
2473         if (lno < top)
2474                 die("file %s has only %lu lines", path, lno);
2475
2476         ent = xcalloc(1, sizeof(*ent));
2477         ent->lno = bottom;
2478         ent->num_lines = top - bottom;
2479         ent->suspect = o;
2480         ent->s_lno = bottom;
2481
2482         sb.ent = ent;
2483         sb.path = path;
2484
2485         if (revs_file && read_ancestry(revs_file))
2486                 die("reading graft file %s failed: %s",
2487                     revs_file, strerror(errno));
2488
2489         read_mailmap(&mailmap, ".mailmap", NULL);
2490
2491         if (!incremental)
2492                 setup_pager();
2493
2494         assign_blame(&sb, opt);
2495
2496         if (incremental)
2497                 return 0;
2498
2499         coalesce(&sb);
2500
2501         if (!(output_option & OUTPUT_PORCELAIN))
2502                 find_alignment(&sb, &output_option);
2503
2504         output(&sb, output_option);
2505         free((void *)sb.final_buf);
2506         for (ent = sb.ent; ent; ) {
2507                 struct blame_entry *e = ent->next;
2508                 free(ent);
2509                 ent = e;
2510         }
2511
2512         if (show_stats) {
2513                 printf("num read blob: %d\n", num_read_blob);
2514                 printf("num get patch: %d\n", num_get_patch);
2515                 printf("num commits: %d\n", num_commits);
2516         }
2517         return 0;
2518 }