Merge branch 'rs/daemon-plug-child-leak'
[git] / builtin / blame.c
1 /*
2  * Blame
3  *
4  * Copyright (c) 2006, 2014 by its authors
5  * See COPYING for licensing conditions
6  */
7
8 #include "cache.h"
9 #include "refs.h"
10 #include "builtin.h"
11 #include "blob.h"
12 #include "commit.h"
13 #include "tag.h"
14 #include "tree-walk.h"
15 #include "diff.h"
16 #include "diffcore.h"
17 #include "revision.h"
18 #include "quote.h"
19 #include "xdiff-interface.h"
20 #include "cache-tree.h"
21 #include "string-list.h"
22 #include "mailmap.h"
23 #include "mergesort.h"
24 #include "parse-options.h"
25 #include "prio-queue.h"
26 #include "utf8.h"
27 #include "userdiff.h"
28 #include "line-range.h"
29 #include "line-log.h"
30 #include "dir.h"
31
32 static char blame_usage[] = N_("git blame [<options>] [<rev-opts>] [<rev>] [--] <file>");
33
34 static const char *blame_opt_usage[] = {
35         blame_usage,
36         "",
37         N_("<rev-opts> are documented in git-rev-list(1)"),
38         NULL
39 };
40
41 static int longest_file;
42 static int longest_author;
43 static int max_orig_digits;
44 static int max_digits;
45 static int max_score_digits;
46 static int show_root;
47 static int reverse;
48 static int blank_boundary;
49 static int incremental;
50 static int xdl_opts;
51 static int abbrev = -1;
52 static int no_whole_file_rename;
53
54 static struct date_mode blame_date_mode = { DATE_ISO8601 };
55 static size_t blame_date_width;
56
57 static struct string_list mailmap;
58
59 #ifndef DEBUG
60 #define DEBUG 0
61 #endif
62
63 /* stats */
64 static int num_read_blob;
65 static int num_get_patch;
66 static int num_commits;
67
68 #define PICKAXE_BLAME_MOVE              01
69 #define PICKAXE_BLAME_COPY              02
70 #define PICKAXE_BLAME_COPY_HARDER       04
71 #define PICKAXE_BLAME_COPY_HARDEST      010
72
73 /*
74  * blame for a blame_entry with score lower than these thresholds
75  * is not passed to the parent using move/copy logic.
76  */
77 static unsigned blame_move_score;
78 static unsigned blame_copy_score;
79 #define BLAME_DEFAULT_MOVE_SCORE        20
80 #define BLAME_DEFAULT_COPY_SCORE        40
81
82 /* Remember to update object flag allocation in object.h */
83 #define METAINFO_SHOWN          (1u<<12)
84 #define MORE_THAN_ONE_PATH      (1u<<13)
85
86 /*
87  * One blob in a commit that is being suspected
88  */
89 struct origin {
90         int refcnt;
91         /* Record preceding blame record for this blob */
92         struct origin *previous;
93         /* origins are put in a list linked via `next' hanging off the
94          * corresponding commit's util field in order to make finding
95          * them fast.  The presence in this chain does not count
96          * towards the origin's reference count.  It is tempting to
97          * let it count as long as the commit is pending examination,
98          * but even under circumstances where the commit will be
99          * present multiple times in the priority queue of unexamined
100          * commits, processing the first instance will not leave any
101          * work requiring the origin data for the second instance.  An
102          * interspersed commit changing that would have to be
103          * preexisting with a different ancestry and with the same
104          * commit date in order to wedge itself between two instances
105          * of the same commit in the priority queue _and_ produce
106          * blame entries relevant for it.  While we don't want to let
107          * us get tripped up by this case, it certainly does not seem
108          * worth optimizing for.
109          */
110         struct origin *next;
111         struct commit *commit;
112         /* `suspects' contains blame entries that may be attributed to
113          * this origin's commit or to parent commits.  When a commit
114          * is being processed, all suspects will be moved, either by
115          * assigning them to an origin in a different commit, or by
116          * shipping them to the scoreboard's ent list because they
117          * cannot be attributed to a different commit.
118          */
119         struct blame_entry *suspects;
120         mmfile_t file;
121         unsigned char blob_sha1[20];
122         unsigned mode;
123         /* guilty gets set when shipping any suspects to the final
124          * blame list instead of other commits
125          */
126         char guilty;
127         char path[FLEX_ARRAY];
128 };
129
130 static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b, long ctxlen,
131                       xdl_emit_hunk_consume_func_t hunk_func, void *cb_data)
132 {
133         xpparam_t xpp = {0};
134         xdemitconf_t xecfg = {0};
135         xdemitcb_t ecb = {NULL};
136
137         xpp.flags = xdl_opts;
138         xecfg.ctxlen = ctxlen;
139         xecfg.hunk_func = hunk_func;
140         ecb.priv = cb_data;
141         return xdi_diff(file_a, file_b, &xpp, &xecfg, &ecb);
142 }
143
144 /*
145  * Prepare diff_filespec and convert it using diff textconv API
146  * if the textconv driver exists.
147  * Return 1 if the conversion succeeds, 0 otherwise.
148  */
149 int textconv_object(const char *path,
150                     unsigned mode,
151                     const unsigned char *sha1,
152                     int sha1_valid,
153                     char **buf,
154                     unsigned long *buf_size)
155 {
156         struct diff_filespec *df;
157         struct userdiff_driver *textconv;
158
159         df = alloc_filespec(path);
160         fill_filespec(df, sha1, sha1_valid, mode);
161         textconv = get_textconv(df);
162         if (!textconv) {
163                 free_filespec(df);
164                 return 0;
165         }
166
167         *buf_size = fill_textconv(textconv, df, buf);
168         free_filespec(df);
169         return 1;
170 }
171
172 /*
173  * Given an origin, prepare mmfile_t structure to be used by the
174  * diff machinery
175  */
176 static void fill_origin_blob(struct diff_options *opt,
177                              struct origin *o, mmfile_t *file)
178 {
179         if (!o->file.ptr) {
180                 enum object_type type;
181                 unsigned long file_size;
182
183                 num_read_blob++;
184                 if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV) &&
185                     textconv_object(o->path, o->mode, o->blob_sha1, 1, &file->ptr, &file_size))
186                         ;
187                 else
188                         file->ptr = read_sha1_file(o->blob_sha1, &type, &file_size);
189                 file->size = file_size;
190
191                 if (!file->ptr)
192                         die("Cannot read blob %s for path %s",
193                             sha1_to_hex(o->blob_sha1),
194                             o->path);
195                 o->file = *file;
196         }
197         else
198                 *file = o->file;
199 }
200
201 /*
202  * Origin is refcounted and usually we keep the blob contents to be
203  * reused.
204  */
205 static inline struct origin *origin_incref(struct origin *o)
206 {
207         if (o)
208                 o->refcnt++;
209         return o;
210 }
211
212 static void origin_decref(struct origin *o)
213 {
214         if (o && --o->refcnt <= 0) {
215                 struct origin *p, *l = NULL;
216                 if (o->previous)
217                         origin_decref(o->previous);
218                 free(o->file.ptr);
219                 /* Should be present exactly once in commit chain */
220                 for (p = o->commit->util; p; l = p, p = p->next) {
221                         if (p == o) {
222                                 if (l)
223                                         l->next = p->next;
224                                 else
225                                         o->commit->util = p->next;
226                                 free(o);
227                                 return;
228                         }
229                 }
230                 die("internal error in blame::origin_decref");
231         }
232 }
233
234 static void drop_origin_blob(struct origin *o)
235 {
236         if (o->file.ptr) {
237                 free(o->file.ptr);
238                 o->file.ptr = NULL;
239         }
240 }
241
242 /*
243  * Each group of lines is described by a blame_entry; it can be split
244  * as we pass blame to the parents.  They are arranged in linked lists
245  * kept as `suspects' of some unprocessed origin, or entered (when the
246  * blame origin has been finalized) into the scoreboard structure.
247  * While the scoreboard structure is only sorted at the end of
248  * processing (according to final image line number), the lists
249  * attached to an origin are sorted by the target line number.
250  */
251 struct blame_entry {
252         struct blame_entry *next;
253
254         /* the first line of this group in the final image;
255          * internally all line numbers are 0 based.
256          */
257         int lno;
258
259         /* how many lines this group has */
260         int num_lines;
261
262         /* the commit that introduced this group into the final image */
263         struct origin *suspect;
264
265         /* the line number of the first line of this group in the
266          * suspect's file; internally all line numbers are 0 based.
267          */
268         int s_lno;
269
270         /* how significant this entry is -- cached to avoid
271          * scanning the lines over and over.
272          */
273         unsigned score;
274 };
275
276 /*
277  * Any merge of blames happens on lists of blames that arrived via
278  * different parents in a single suspect.  In this case, we want to
279  * sort according to the suspect line numbers as opposed to the final
280  * image line numbers.  The function body is somewhat longish because
281  * it avoids unnecessary writes.
282  */
283
284 static struct blame_entry *blame_merge(struct blame_entry *list1,
285                                        struct blame_entry *list2)
286 {
287         struct blame_entry *p1 = list1, *p2 = list2,
288                 **tail = &list1;
289
290         if (!p1)
291                 return p2;
292         if (!p2)
293                 return p1;
294
295         if (p1->s_lno <= p2->s_lno) {
296                 do {
297                         tail = &p1->next;
298                         if ((p1 = *tail) == NULL) {
299                                 *tail = p2;
300                                 return list1;
301                         }
302                 } while (p1->s_lno <= p2->s_lno);
303         }
304         for (;;) {
305                 *tail = p2;
306                 do {
307                         tail = &p2->next;
308                         if ((p2 = *tail) == NULL)  {
309                                 *tail = p1;
310                                 return list1;
311                         }
312                 } while (p1->s_lno > p2->s_lno);
313                 *tail = p1;
314                 do {
315                         tail = &p1->next;
316                         if ((p1 = *tail) == NULL) {
317                                 *tail = p2;
318                                 return list1;
319                         }
320                 } while (p1->s_lno <= p2->s_lno);
321         }
322 }
323
324 static void *get_next_blame(const void *p)
325 {
326         return ((struct blame_entry *)p)->next;
327 }
328
329 static void set_next_blame(void *p1, void *p2)
330 {
331         ((struct blame_entry *)p1)->next = p2;
332 }
333
334 /*
335  * Final image line numbers are all different, so we don't need a
336  * three-way comparison here.
337  */
338
339 static int compare_blame_final(const void *p1, const void *p2)
340 {
341         return ((struct blame_entry *)p1)->lno > ((struct blame_entry *)p2)->lno
342                 ? 1 : -1;
343 }
344
345 static int compare_blame_suspect(const void *p1, const void *p2)
346 {
347         const struct blame_entry *s1 = p1, *s2 = p2;
348         /*
349          * to allow for collating suspects, we sort according to the
350          * respective pointer value as the primary sorting criterion.
351          * The actual relation is pretty unimportant as long as it
352          * establishes a total order.  Comparing as integers gives us
353          * that.
354          */
355         if (s1->suspect != s2->suspect)
356                 return (intptr_t)s1->suspect > (intptr_t)s2->suspect ? 1 : -1;
357         if (s1->s_lno == s2->s_lno)
358                 return 0;
359         return s1->s_lno > s2->s_lno ? 1 : -1;
360 }
361
362 static struct blame_entry *blame_sort(struct blame_entry *head,
363                                       int (*compare_fn)(const void *, const void *))
364 {
365         return llist_mergesort (head, get_next_blame, set_next_blame, compare_fn);
366 }
367
368 static int compare_commits_by_reverse_commit_date(const void *a,
369                                                   const void *b,
370                                                   void *c)
371 {
372         return -compare_commits_by_commit_date(a, b, c);
373 }
374
375 /*
376  * The current state of the blame assignment.
377  */
378 struct scoreboard {
379         /* the final commit (i.e. where we started digging from) */
380         struct commit *final;
381         /* Priority queue for commits with unassigned blame records */
382         struct prio_queue commits;
383         struct rev_info *revs;
384         const char *path;
385
386         /*
387          * The contents in the final image.
388          * Used by many functions to obtain contents of the nth line,
389          * indexed with scoreboard.lineno[blame_entry.lno].
390          */
391         const char *final_buf;
392         unsigned long final_buf_size;
393
394         /* linked list of blames */
395         struct blame_entry *ent;
396
397         /* look-up a line in the final buffer */
398         int num_lines;
399         int *lineno;
400 };
401
402 static void sanity_check_refcnt(struct scoreboard *);
403
404 /*
405  * If two blame entries that are next to each other came from
406  * contiguous lines in the same origin (i.e. <commit, path> pair),
407  * merge them together.
408  */
409 static void coalesce(struct scoreboard *sb)
410 {
411         struct blame_entry *ent, *next;
412
413         for (ent = sb->ent; ent && (next = ent->next); ent = next) {
414                 if (ent->suspect == next->suspect &&
415                     ent->s_lno + ent->num_lines == next->s_lno) {
416                         ent->num_lines += next->num_lines;
417                         ent->next = next->next;
418                         origin_decref(next->suspect);
419                         free(next);
420                         ent->score = 0;
421                         next = ent; /* again */
422                 }
423         }
424
425         if (DEBUG) /* sanity */
426                 sanity_check_refcnt(sb);
427 }
428
429 /*
430  * Merge the given sorted list of blames into a preexisting origin.
431  * If there were no previous blames to that commit, it is entered into
432  * the commit priority queue of the score board.
433  */
434
435 static void queue_blames(struct scoreboard *sb, struct origin *porigin,
436                          struct blame_entry *sorted)
437 {
438         if (porigin->suspects)
439                 porigin->suspects = blame_merge(porigin->suspects, sorted);
440         else {
441                 struct origin *o;
442                 for (o = porigin->commit->util; o; o = o->next) {
443                         if (o->suspects) {
444                                 porigin->suspects = sorted;
445                                 return;
446                         }
447                 }
448                 porigin->suspects = sorted;
449                 prio_queue_put(&sb->commits, porigin->commit);
450         }
451 }
452
453 /*
454  * Given a commit and a path in it, create a new origin structure.
455  * The callers that add blame to the scoreboard should use
456  * get_origin() to obtain shared, refcounted copy instead of calling
457  * this function directly.
458  */
459 static struct origin *make_origin(struct commit *commit, const char *path)
460 {
461         struct origin *o;
462         size_t pathlen = strlen(path) + 1;
463         o = xcalloc(1, sizeof(*o) + pathlen);
464         o->commit = commit;
465         o->refcnt = 1;
466         o->next = commit->util;
467         commit->util = o;
468         memcpy(o->path, path, pathlen); /* includes NUL */
469         return o;
470 }
471
472 /*
473  * Locate an existing origin or create a new one.
474  * This moves the origin to front position in the commit util list.
475  */
476 static struct origin *get_origin(struct scoreboard *sb,
477                                  struct commit *commit,
478                                  const char *path)
479 {
480         struct origin *o, *l;
481
482         for (o = commit->util, l = NULL; o; l = o, o = o->next) {
483                 if (!strcmp(o->path, path)) {
484                         /* bump to front */
485                         if (l) {
486                                 l->next = o->next;
487                                 o->next = commit->util;
488                                 commit->util = o;
489                         }
490                         return origin_incref(o);
491                 }
492         }
493         return make_origin(commit, path);
494 }
495
496 /*
497  * Fill the blob_sha1 field of an origin if it hasn't, so that later
498  * call to fill_origin_blob() can use it to locate the data.  blob_sha1
499  * for an origin is also used to pass the blame for the entire file to
500  * the parent to detect the case where a child's blob is identical to
501  * that of its parent's.
502  *
503  * This also fills origin->mode for corresponding tree path.
504  */
505 static int fill_blob_sha1_and_mode(struct origin *origin)
506 {
507         if (!is_null_sha1(origin->blob_sha1))
508                 return 0;
509         if (get_tree_entry(origin->commit->object.sha1,
510                            origin->path,
511                            origin->blob_sha1, &origin->mode))
512                 goto error_out;
513         if (sha1_object_info(origin->blob_sha1, NULL) != OBJ_BLOB)
514                 goto error_out;
515         return 0;
516  error_out:
517         hashclr(origin->blob_sha1);
518         origin->mode = S_IFINVALID;
519         return -1;
520 }
521
522 /*
523  * We have an origin -- check if the same path exists in the
524  * parent and return an origin structure to represent it.
525  */
526 static struct origin *find_origin(struct scoreboard *sb,
527                                   struct commit *parent,
528                                   struct origin *origin)
529 {
530         struct origin *porigin;
531         struct diff_options diff_opts;
532         const char *paths[2];
533
534         /* First check any existing origins */
535         for (porigin = parent->util; porigin; porigin = porigin->next)
536                 if (!strcmp(porigin->path, origin->path)) {
537                         /*
538                          * The same path between origin and its parent
539                          * without renaming -- the most common case.
540                          */
541                         return origin_incref (porigin);
542                 }
543
544         /* See if the origin->path is different between parent
545          * and origin first.  Most of the time they are the
546          * same and diff-tree is fairly efficient about this.
547          */
548         diff_setup(&diff_opts);
549         DIFF_OPT_SET(&diff_opts, RECURSIVE);
550         diff_opts.detect_rename = 0;
551         diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
552         paths[0] = origin->path;
553         paths[1] = NULL;
554
555         parse_pathspec(&diff_opts.pathspec,
556                        PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
557                        PATHSPEC_LITERAL_PATH, "", paths);
558         diff_setup_done(&diff_opts);
559
560         if (is_null_sha1(origin->commit->object.sha1))
561                 do_diff_cache(parent->tree->object.sha1, &diff_opts);
562         else
563                 diff_tree_sha1(parent->tree->object.sha1,
564                                origin->commit->tree->object.sha1,
565                                "", &diff_opts);
566         diffcore_std(&diff_opts);
567
568         if (!diff_queued_diff.nr) {
569                 /* The path is the same as parent */
570                 porigin = get_origin(sb, parent, origin->path);
571                 hashcpy(porigin->blob_sha1, origin->blob_sha1);
572                 porigin->mode = origin->mode;
573         } else {
574                 /*
575                  * Since origin->path is a pathspec, if the parent
576                  * commit had it as a directory, we will see a whole
577                  * bunch of deletion of files in the directory that we
578                  * do not care about.
579                  */
580                 int i;
581                 struct diff_filepair *p = NULL;
582                 for (i = 0; i < diff_queued_diff.nr; i++) {
583                         const char *name;
584                         p = diff_queued_diff.queue[i];
585                         name = p->one->path ? p->one->path : p->two->path;
586                         if (!strcmp(name, origin->path))
587                                 break;
588                 }
589                 if (!p)
590                         die("internal error in blame::find_origin");
591                 switch (p->status) {
592                 default:
593                         die("internal error in blame::find_origin (%c)",
594                             p->status);
595                 case 'M':
596                         porigin = get_origin(sb, parent, origin->path);
597                         hashcpy(porigin->blob_sha1, p->one->sha1);
598                         porigin->mode = p->one->mode;
599                         break;
600                 case 'A':
601                 case 'T':
602                         /* Did not exist in parent, or type changed */
603                         break;
604                 }
605         }
606         diff_flush(&diff_opts);
607         free_pathspec(&diff_opts.pathspec);
608         return porigin;
609 }
610
611 /*
612  * We have an origin -- find the path that corresponds to it in its
613  * parent and return an origin structure to represent it.
614  */
615 static struct origin *find_rename(struct scoreboard *sb,
616                                   struct commit *parent,
617                                   struct origin *origin)
618 {
619         struct origin *porigin = NULL;
620         struct diff_options diff_opts;
621         int i;
622
623         diff_setup(&diff_opts);
624         DIFF_OPT_SET(&diff_opts, RECURSIVE);
625         diff_opts.detect_rename = DIFF_DETECT_RENAME;
626         diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
627         diff_opts.single_follow = origin->path;
628         diff_setup_done(&diff_opts);
629
630         if (is_null_sha1(origin->commit->object.sha1))
631                 do_diff_cache(parent->tree->object.sha1, &diff_opts);
632         else
633                 diff_tree_sha1(parent->tree->object.sha1,
634                                origin->commit->tree->object.sha1,
635                                "", &diff_opts);
636         diffcore_std(&diff_opts);
637
638         for (i = 0; i < diff_queued_diff.nr; i++) {
639                 struct diff_filepair *p = diff_queued_diff.queue[i];
640                 if ((p->status == 'R' || p->status == 'C') &&
641                     !strcmp(p->two->path, origin->path)) {
642                         porigin = get_origin(sb, parent, p->one->path);
643                         hashcpy(porigin->blob_sha1, p->one->sha1);
644                         porigin->mode = p->one->mode;
645                         break;
646                 }
647         }
648         diff_flush(&diff_opts);
649         free_pathspec(&diff_opts.pathspec);
650         return porigin;
651 }
652
653 /*
654  * Append a new blame entry to a given output queue.
655  */
656 static void add_blame_entry(struct blame_entry ***queue, struct blame_entry *e)
657 {
658         origin_incref(e->suspect);
659
660         e->next = **queue;
661         **queue = e;
662         *queue = &e->next;
663 }
664
665 /*
666  * src typically is on-stack; we want to copy the information in it to
667  * a malloced blame_entry that gets added to the given queue.  The
668  * origin of dst loses a refcnt.
669  */
670 static void dup_entry(struct blame_entry ***queue,
671                       struct blame_entry *dst, struct blame_entry *src)
672 {
673         origin_incref(src->suspect);
674         origin_decref(dst->suspect);
675         memcpy(dst, src, sizeof(*src));
676         dst->next = **queue;
677         **queue = dst;
678         *queue = &dst->next;
679 }
680
681 static const char *nth_line(struct scoreboard *sb, long lno)
682 {
683         return sb->final_buf + sb->lineno[lno];
684 }
685
686 static const char *nth_line_cb(void *data, long lno)
687 {
688         return nth_line((struct scoreboard *)data, lno);
689 }
690
691 /*
692  * It is known that lines between tlno to same came from parent, and e
693  * has an overlap with that range.  it also is known that parent's
694  * line plno corresponds to e's line tlno.
695  *
696  *                <---- e ----->
697  *                   <------>
698  *                   <------------>
699  *             <------------>
700  *             <------------------>
701  *
702  * Split e into potentially three parts; before this chunk, the chunk
703  * to be blamed for the parent, and after that portion.
704  */
705 static void split_overlap(struct blame_entry *split,
706                           struct blame_entry *e,
707                           int tlno, int plno, int same,
708                           struct origin *parent)
709 {
710         int chunk_end_lno;
711         memset(split, 0, sizeof(struct blame_entry [3]));
712
713         if (e->s_lno < tlno) {
714                 /* there is a pre-chunk part not blamed on parent */
715                 split[0].suspect = origin_incref(e->suspect);
716                 split[0].lno = e->lno;
717                 split[0].s_lno = e->s_lno;
718                 split[0].num_lines = tlno - e->s_lno;
719                 split[1].lno = e->lno + tlno - e->s_lno;
720                 split[1].s_lno = plno;
721         }
722         else {
723                 split[1].lno = e->lno;
724                 split[1].s_lno = plno + (e->s_lno - tlno);
725         }
726
727         if (same < e->s_lno + e->num_lines) {
728                 /* there is a post-chunk part not blamed on parent */
729                 split[2].suspect = origin_incref(e->suspect);
730                 split[2].lno = e->lno + (same - e->s_lno);
731                 split[2].s_lno = e->s_lno + (same - e->s_lno);
732                 split[2].num_lines = e->s_lno + e->num_lines - same;
733                 chunk_end_lno = split[2].lno;
734         }
735         else
736                 chunk_end_lno = e->lno + e->num_lines;
737         split[1].num_lines = chunk_end_lno - split[1].lno;
738
739         /*
740          * if it turns out there is nothing to blame the parent for,
741          * forget about the splitting.  !split[1].suspect signals this.
742          */
743         if (split[1].num_lines < 1)
744                 return;
745         split[1].suspect = origin_incref(parent);
746 }
747
748 /*
749  * split_overlap() divided an existing blame e into up to three parts
750  * in split.  Any assigned blame is moved to queue to
751  * reflect the split.
752  */
753 static void split_blame(struct blame_entry ***blamed,
754                         struct blame_entry ***unblamed,
755                         struct blame_entry *split,
756                         struct blame_entry *e)
757 {
758         struct blame_entry *new_entry;
759
760         if (split[0].suspect && split[2].suspect) {
761                 /* The first part (reuse storage for the existing entry e) */
762                 dup_entry(unblamed, e, &split[0]);
763
764                 /* The last part -- me */
765                 new_entry = xmalloc(sizeof(*new_entry));
766                 memcpy(new_entry, &(split[2]), sizeof(struct blame_entry));
767                 add_blame_entry(unblamed, new_entry);
768
769                 /* ... and the middle part -- parent */
770                 new_entry = xmalloc(sizeof(*new_entry));
771                 memcpy(new_entry, &(split[1]), sizeof(struct blame_entry));
772                 add_blame_entry(blamed, new_entry);
773         }
774         else if (!split[0].suspect && !split[2].suspect)
775                 /*
776                  * The parent covers the entire area; reuse storage for
777                  * e and replace it with the parent.
778                  */
779                 dup_entry(blamed, e, &split[1]);
780         else if (split[0].suspect) {
781                 /* me and then parent */
782                 dup_entry(unblamed, e, &split[0]);
783
784                 new_entry = xmalloc(sizeof(*new_entry));
785                 memcpy(new_entry, &(split[1]), sizeof(struct blame_entry));
786                 add_blame_entry(blamed, new_entry);
787         }
788         else {
789                 /* parent and then me */
790                 dup_entry(blamed, e, &split[1]);
791
792                 new_entry = xmalloc(sizeof(*new_entry));
793                 memcpy(new_entry, &(split[2]), sizeof(struct blame_entry));
794                 add_blame_entry(unblamed, new_entry);
795         }
796 }
797
798 /*
799  * After splitting the blame, the origins used by the
800  * on-stack blame_entry should lose one refcnt each.
801  */
802 static void decref_split(struct blame_entry *split)
803 {
804         int i;
805
806         for (i = 0; i < 3; i++)
807                 origin_decref(split[i].suspect);
808 }
809
810 /*
811  * reverse_blame reverses the list given in head, appending tail.
812  * That allows us to build lists in reverse order, then reverse them
813  * afterwards.  This can be faster than building the list in proper
814  * order right away.  The reason is that building in proper order
815  * requires writing a link in the _previous_ element, while building
816  * in reverse order just requires placing the list head into the
817  * _current_ element.
818  */
819
820 static struct blame_entry *reverse_blame(struct blame_entry *head,
821                                          struct blame_entry *tail)
822 {
823         while (head) {
824                 struct blame_entry *next = head->next;
825                 head->next = tail;
826                 tail = head;
827                 head = next;
828         }
829         return tail;
830 }
831
832 /*
833  * Process one hunk from the patch between the current suspect for
834  * blame_entry e and its parent.  This first blames any unfinished
835  * entries before the chunk (which is where target and parent start
836  * differing) on the parent, and then splits blame entries at the
837  * start and at the end of the difference region.  Since use of -M and
838  * -C options may lead to overlapping/duplicate source line number
839  * ranges, all we can rely on from sorting/merging is the order of the
840  * first suspect line number.
841  */
842 static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
843                         int tlno, int offset, int same,
844                         struct origin *parent)
845 {
846         struct blame_entry *e = **srcq;
847         struct blame_entry *samep = NULL, *diffp = NULL;
848
849         while (e && e->s_lno < tlno) {
850                 struct blame_entry *next = e->next;
851                 /*
852                  * current record starts before differing portion.  If
853                  * it reaches into it, we need to split it up and
854                  * examine the second part separately.
855                  */
856                 if (e->s_lno + e->num_lines > tlno) {
857                         /* Move second half to a new record */
858                         int len = tlno - e->s_lno;
859                         struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
860                         n->suspect = e->suspect;
861                         n->lno = e->lno + len;
862                         n->s_lno = e->s_lno + len;
863                         n->num_lines = e->num_lines - len;
864                         e->num_lines = len;
865                         e->score = 0;
866                         /* Push new record to diffp */
867                         n->next = diffp;
868                         diffp = n;
869                 } else
870                         origin_decref(e->suspect);
871                 /* Pass blame for everything before the differing
872                  * chunk to the parent */
873                 e->suspect = origin_incref(parent);
874                 e->s_lno += offset;
875                 e->next = samep;
876                 samep = e;
877                 e = next;
878         }
879         /*
880          * As we don't know how much of a common stretch after this
881          * diff will occur, the currently blamed parts are all that we
882          * can assign to the parent for now.
883          */
884
885         if (samep) {
886                 **dstq = reverse_blame(samep, **dstq);
887                 *dstq = &samep->next;
888         }
889         /*
890          * Prepend the split off portions: everything after e starts
891          * after the blameable portion.
892          */
893         e = reverse_blame(diffp, e);
894
895         /*
896          * Now retain records on the target while parts are different
897          * from the parent.
898          */
899         samep = NULL;
900         diffp = NULL;
901         while (e && e->s_lno < same) {
902                 struct blame_entry *next = e->next;
903
904                 /*
905                  * If current record extends into sameness, need to split.
906                  */
907                 if (e->s_lno + e->num_lines > same) {
908                         /*
909                          * Move second half to a new record to be
910                          * processed by later chunks
911                          */
912                         int len = same - e->s_lno;
913                         struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
914                         n->suspect = origin_incref(e->suspect);
915                         n->lno = e->lno + len;
916                         n->s_lno = e->s_lno + len;
917                         n->num_lines = e->num_lines - len;
918                         e->num_lines = len;
919                         e->score = 0;
920                         /* Push new record to samep */
921                         n->next = samep;
922                         samep = n;
923                 }
924                 e->next = diffp;
925                 diffp = e;
926                 e = next;
927         }
928         **srcq = reverse_blame(diffp, reverse_blame(samep, e));
929         /* Move across elements that are in the unblamable portion */
930         if (diffp)
931                 *srcq = &diffp->next;
932 }
933
934 struct blame_chunk_cb_data {
935         struct origin *parent;
936         long offset;
937         struct blame_entry **dstq;
938         struct blame_entry **srcq;
939 };
940
941 /* diff chunks are from parent to target */
942 static int blame_chunk_cb(long start_a, long count_a,
943                           long start_b, long count_b, void *data)
944 {
945         struct blame_chunk_cb_data *d = data;
946         if (start_a - start_b != d->offset)
947                 die("internal error in blame::blame_chunk_cb");
948         blame_chunk(&d->dstq, &d->srcq, start_b, start_a - start_b,
949                     start_b + count_b, d->parent);
950         d->offset = start_a + count_a - (start_b + count_b);
951         return 0;
952 }
953
954 /*
955  * We are looking at the origin 'target' and aiming to pass blame
956  * for the lines it is suspected to its parent.  Run diff to find
957  * which lines came from parent and pass blame for them.
958  */
959 static void pass_blame_to_parent(struct scoreboard *sb,
960                                  struct origin *target,
961                                  struct origin *parent)
962 {
963         mmfile_t file_p, file_o;
964         struct blame_chunk_cb_data d;
965         struct blame_entry *newdest = NULL;
966
967         if (!target->suspects)
968                 return; /* nothing remains for this target */
969
970         d.parent = parent;
971         d.offset = 0;
972         d.dstq = &newdest; d.srcq = &target->suspects;
973
974         fill_origin_blob(&sb->revs->diffopt, parent, &file_p);
975         fill_origin_blob(&sb->revs->diffopt, target, &file_o);
976         num_get_patch++;
977
978         if (diff_hunks(&file_p, &file_o, 0, blame_chunk_cb, &d))
979                 die("unable to generate diff (%s -> %s)",
980                     sha1_to_hex(parent->commit->object.sha1),
981                     sha1_to_hex(target->commit->object.sha1));
982         /* The rest are the same as the parent */
983         blame_chunk(&d.dstq, &d.srcq, INT_MAX, d.offset, INT_MAX, parent);
984         *d.dstq = NULL;
985         queue_blames(sb, parent, newdest);
986
987         return;
988 }
989
990 /*
991  * The lines in blame_entry after splitting blames many times can become
992  * very small and trivial, and at some point it becomes pointless to
993  * blame the parents.  E.g. "\t\t}\n\t}\n\n" appears everywhere in any
994  * ordinary C program, and it is not worth to say it was copied from
995  * totally unrelated file in the parent.
996  *
997  * Compute how trivial the lines in the blame_entry are.
998  */
999 static unsigned ent_score(struct scoreboard *sb, struct blame_entry *e)
1000 {
1001         unsigned score;
1002         const char *cp, *ep;
1003
1004         if (e->score)
1005                 return e->score;
1006
1007         score = 1;
1008         cp = nth_line(sb, e->lno);
1009         ep = nth_line(sb, e->lno + e->num_lines);
1010         while (cp < ep) {
1011                 unsigned ch = *((unsigned char *)cp);
1012                 if (isalnum(ch))
1013                         score++;
1014                 cp++;
1015         }
1016         e->score = score;
1017         return score;
1018 }
1019
1020 /*
1021  * best_so_far[] and this[] are both a split of an existing blame_entry
1022  * that passes blame to the parent.  Maintain best_so_far the best split
1023  * so far, by comparing this and best_so_far and copying this into
1024  * bst_so_far as needed.
1025  */
1026 static void copy_split_if_better(struct scoreboard *sb,
1027                                  struct blame_entry *best_so_far,
1028                                  struct blame_entry *this)
1029 {
1030         int i;
1031
1032         if (!this[1].suspect)
1033                 return;
1034         if (best_so_far[1].suspect) {
1035                 if (ent_score(sb, &this[1]) < ent_score(sb, &best_so_far[1]))
1036                         return;
1037         }
1038
1039         for (i = 0; i < 3; i++)
1040                 origin_incref(this[i].suspect);
1041         decref_split(best_so_far);
1042         memcpy(best_so_far, this, sizeof(struct blame_entry [3]));
1043 }
1044
1045 /*
1046  * We are looking at a part of the final image represented by
1047  * ent (tlno and same are offset by ent->s_lno).
1048  * tlno is where we are looking at in the final image.
1049  * up to (but not including) same match preimage.
1050  * plno is where we are looking at in the preimage.
1051  *
1052  * <-------------- final image ---------------------->
1053  *       <------ent------>
1054  *         ^tlno ^same
1055  *    <---------preimage----->
1056  *         ^plno
1057  *
1058  * All line numbers are 0-based.
1059  */
1060 static void handle_split(struct scoreboard *sb,
1061                          struct blame_entry *ent,
1062                          int tlno, int plno, int same,
1063                          struct origin *parent,
1064                          struct blame_entry *split)
1065 {
1066         if (ent->num_lines <= tlno)
1067                 return;
1068         if (tlno < same) {
1069                 struct blame_entry this[3];
1070                 tlno += ent->s_lno;
1071                 same += ent->s_lno;
1072                 split_overlap(this, ent, tlno, plno, same, parent);
1073                 copy_split_if_better(sb, split, this);
1074                 decref_split(this);
1075         }
1076 }
1077
1078 struct handle_split_cb_data {
1079         struct scoreboard *sb;
1080         struct blame_entry *ent;
1081         struct origin *parent;
1082         struct blame_entry *split;
1083         long plno;
1084         long tlno;
1085 };
1086
1087 static int handle_split_cb(long start_a, long count_a,
1088                            long start_b, long count_b, void *data)
1089 {
1090         struct handle_split_cb_data *d = data;
1091         handle_split(d->sb, d->ent, d->tlno, d->plno, start_b, d->parent,
1092                      d->split);
1093         d->plno = start_a + count_a;
1094         d->tlno = start_b + count_b;
1095         return 0;
1096 }
1097
1098 /*
1099  * Find the lines from parent that are the same as ent so that
1100  * we can pass blames to it.  file_p has the blob contents for
1101  * the parent.
1102  */
1103 static void find_copy_in_blob(struct scoreboard *sb,
1104                               struct blame_entry *ent,
1105                               struct origin *parent,
1106                               struct blame_entry *split,
1107                               mmfile_t *file_p)
1108 {
1109         const char *cp;
1110         mmfile_t file_o;
1111         struct handle_split_cb_data d;
1112
1113         memset(&d, 0, sizeof(d));
1114         d.sb = sb; d.ent = ent; d.parent = parent; d.split = split;
1115         /*
1116          * Prepare mmfile that contains only the lines in ent.
1117          */
1118         cp = nth_line(sb, ent->lno);
1119         file_o.ptr = (char *) cp;
1120         file_o.size = nth_line(sb, ent->lno + ent->num_lines) - cp;
1121
1122         /*
1123          * file_o is a part of final image we are annotating.
1124          * file_p partially may match that image.
1125          */
1126         memset(split, 0, sizeof(struct blame_entry [3]));
1127         if (diff_hunks(file_p, &file_o, 1, handle_split_cb, &d))
1128                 die("unable to generate diff (%s)",
1129                     sha1_to_hex(parent->commit->object.sha1));
1130         /* remainder, if any, all match the preimage */
1131         handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split);
1132 }
1133
1134 /* Move all blame entries from list *source that have a score smaller
1135  * than score_min to the front of list *small.
1136  * Returns a pointer to the link pointing to the old head of the small list.
1137  */
1138
1139 static struct blame_entry **filter_small(struct scoreboard *sb,
1140                                          struct blame_entry **small,
1141                                          struct blame_entry **source,
1142                                          unsigned score_min)
1143 {
1144         struct blame_entry *p = *source;
1145         struct blame_entry *oldsmall = *small;
1146         while (p) {
1147                 if (ent_score(sb, p) <= score_min) {
1148                         *small = p;
1149                         small = &p->next;
1150                         p = *small;
1151                 } else {
1152                         *source = p;
1153                         source = &p->next;
1154                         p = *source;
1155                 }
1156         }
1157         *small = oldsmall;
1158         *source = NULL;
1159         return small;
1160 }
1161
1162 /*
1163  * See if lines currently target is suspected for can be attributed to
1164  * parent.
1165  */
1166 static void find_move_in_parent(struct scoreboard *sb,
1167                                 struct blame_entry ***blamed,
1168                                 struct blame_entry **toosmall,
1169                                 struct origin *target,
1170                                 struct origin *parent)
1171 {
1172         struct blame_entry *e, split[3];
1173         struct blame_entry *unblamed = target->suspects;
1174         struct blame_entry *leftover = NULL;
1175         mmfile_t file_p;
1176
1177         if (!unblamed)
1178                 return; /* nothing remains for this target */
1179
1180         fill_origin_blob(&sb->revs->diffopt, parent, &file_p);
1181         if (!file_p.ptr)
1182                 return;
1183
1184         /* At each iteration, unblamed has a NULL-terminated list of
1185          * entries that have not yet been tested for blame.  leftover
1186          * contains the reversed list of entries that have been tested
1187          * without being assignable to the parent.
1188          */
1189         do {
1190                 struct blame_entry **unblamedtail = &unblamed;
1191                 struct blame_entry *next;
1192                 for (e = unblamed; e; e = next) {
1193                         next = e->next;
1194                         find_copy_in_blob(sb, e, parent, split, &file_p);
1195                         if (split[1].suspect &&
1196                             blame_move_score < ent_score(sb, &split[1])) {
1197                                 split_blame(blamed, &unblamedtail, split, e);
1198                         } else {
1199                                 e->next = leftover;
1200                                 leftover = e;
1201                         }
1202                         decref_split(split);
1203                 }
1204                 *unblamedtail = NULL;
1205                 toosmall = filter_small(sb, toosmall, &unblamed, blame_move_score);
1206         } while (unblamed);
1207         target->suspects = reverse_blame(leftover, NULL);
1208 }
1209
1210 struct blame_list {
1211         struct blame_entry *ent;
1212         struct blame_entry split[3];
1213 };
1214
1215 /*
1216  * Count the number of entries the target is suspected for,
1217  * and prepare a list of entry and the best split.
1218  */
1219 static struct blame_list *setup_blame_list(struct blame_entry *unblamed,
1220                                            int *num_ents_p)
1221 {
1222         struct blame_entry *e;
1223         int num_ents, i;
1224         struct blame_list *blame_list = NULL;
1225
1226         for (e = unblamed, num_ents = 0; e; e = e->next)
1227                 num_ents++;
1228         if (num_ents) {
1229                 blame_list = xcalloc(num_ents, sizeof(struct blame_list));
1230                 for (e = unblamed, i = 0; e; e = e->next)
1231                         blame_list[i++].ent = e;
1232         }
1233         *num_ents_p = num_ents;
1234         return blame_list;
1235 }
1236
1237 /*
1238  * For lines target is suspected for, see if we can find code movement
1239  * across file boundary from the parent commit.  porigin is the path
1240  * in the parent we already tried.
1241  */
1242 static void find_copy_in_parent(struct scoreboard *sb,
1243                                 struct blame_entry ***blamed,
1244                                 struct blame_entry **toosmall,
1245                                 struct origin *target,
1246                                 struct commit *parent,
1247                                 struct origin *porigin,
1248                                 int opt)
1249 {
1250         struct diff_options diff_opts;
1251         int i, j;
1252         struct blame_list *blame_list;
1253         int num_ents;
1254         struct blame_entry *unblamed = target->suspects;
1255         struct blame_entry *leftover = NULL;
1256
1257         if (!unblamed)
1258                 return; /* nothing remains for this target */
1259
1260         diff_setup(&diff_opts);
1261         DIFF_OPT_SET(&diff_opts, RECURSIVE);
1262         diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1263
1264         diff_setup_done(&diff_opts);
1265
1266         /* Try "find copies harder" on new path if requested;
1267          * we do not want to use diffcore_rename() actually to
1268          * match things up; find_copies_harder is set only to
1269          * force diff_tree_sha1() to feed all filepairs to diff_queue,
1270          * and this code needs to be after diff_setup_done(), which
1271          * usually makes find-copies-harder imply copy detection.
1272          */
1273         if ((opt & PICKAXE_BLAME_COPY_HARDEST)
1274             || ((opt & PICKAXE_BLAME_COPY_HARDER)
1275                 && (!porigin || strcmp(target->path, porigin->path))))
1276                 DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
1277
1278         if (is_null_sha1(target->commit->object.sha1))
1279                 do_diff_cache(parent->tree->object.sha1, &diff_opts);
1280         else
1281                 diff_tree_sha1(parent->tree->object.sha1,
1282                                target->commit->tree->object.sha1,
1283                                "", &diff_opts);
1284
1285         if (!DIFF_OPT_TST(&diff_opts, FIND_COPIES_HARDER))
1286                 diffcore_std(&diff_opts);
1287
1288         do {
1289                 struct blame_entry **unblamedtail = &unblamed;
1290                 blame_list = setup_blame_list(unblamed, &num_ents);
1291
1292                 for (i = 0; i < diff_queued_diff.nr; i++) {
1293                         struct diff_filepair *p = diff_queued_diff.queue[i];
1294                         struct origin *norigin;
1295                         mmfile_t file_p;
1296                         struct blame_entry this[3];
1297
1298                         if (!DIFF_FILE_VALID(p->one))
1299                                 continue; /* does not exist in parent */
1300                         if (S_ISGITLINK(p->one->mode))
1301                                 continue; /* ignore git links */
1302                         if (porigin && !strcmp(p->one->path, porigin->path))
1303                                 /* find_move already dealt with this path */
1304                                 continue;
1305
1306                         norigin = get_origin(sb, parent, p->one->path);
1307                         hashcpy(norigin->blob_sha1, p->one->sha1);
1308                         norigin->mode = p->one->mode;
1309                         fill_origin_blob(&sb->revs->diffopt, norigin, &file_p);
1310                         if (!file_p.ptr)
1311                                 continue;
1312
1313                         for (j = 0; j < num_ents; j++) {
1314                                 find_copy_in_blob(sb, blame_list[j].ent,
1315                                                   norigin, this, &file_p);
1316                                 copy_split_if_better(sb, blame_list[j].split,
1317                                                      this);
1318                                 decref_split(this);
1319                         }
1320                         origin_decref(norigin);
1321                 }
1322
1323                 for (j = 0; j < num_ents; j++) {
1324                         struct blame_entry *split = blame_list[j].split;
1325                         if (split[1].suspect &&
1326                             blame_copy_score < ent_score(sb, &split[1])) {
1327                                 split_blame(blamed, &unblamedtail, split,
1328                                             blame_list[j].ent);
1329                         } else {
1330                                 blame_list[j].ent->next = leftover;
1331                                 leftover = blame_list[j].ent;
1332                         }
1333                         decref_split(split);
1334                 }
1335                 free(blame_list);
1336                 *unblamedtail = NULL;
1337                 toosmall = filter_small(sb, toosmall, &unblamed, blame_copy_score);
1338         } while (unblamed);
1339         target->suspects = reverse_blame(leftover, NULL);
1340         diff_flush(&diff_opts);
1341         free_pathspec(&diff_opts.pathspec);
1342 }
1343
1344 /*
1345  * The blobs of origin and porigin exactly match, so everything
1346  * origin is suspected for can be blamed on the parent.
1347  */
1348 static void pass_whole_blame(struct scoreboard *sb,
1349                              struct origin *origin, struct origin *porigin)
1350 {
1351         struct blame_entry *e, *suspects;
1352
1353         if (!porigin->file.ptr && origin->file.ptr) {
1354                 /* Steal its file */
1355                 porigin->file = origin->file;
1356                 origin->file.ptr = NULL;
1357         }
1358         suspects = origin->suspects;
1359         origin->suspects = NULL;
1360         for (e = suspects; e; e = e->next) {
1361                 origin_incref(porigin);
1362                 origin_decref(e->suspect);
1363                 e->suspect = porigin;
1364         }
1365         queue_blames(sb, porigin, suspects);
1366 }
1367
1368 /*
1369  * We pass blame from the current commit to its parents.  We keep saying
1370  * "parent" (and "porigin"), but what we mean is to find scapegoat to
1371  * exonerate ourselves.
1372  */
1373 static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit)
1374 {
1375         if (!reverse) {
1376                 if (revs->first_parent_only &&
1377                     commit->parents &&
1378                     commit->parents->next) {
1379                         free_commit_list(commit->parents->next);
1380                         commit->parents->next = NULL;
1381                 }
1382                 return commit->parents;
1383         }
1384         return lookup_decoration(&revs->children, &commit->object);
1385 }
1386
1387 static int num_scapegoats(struct rev_info *revs, struct commit *commit)
1388 {
1389         struct commit_list *l = first_scapegoat(revs, commit);
1390         return commit_list_count(l);
1391 }
1392
1393 /* Distribute collected unsorted blames to the respected sorted lists
1394  * in the various origins.
1395  */
1396 static void distribute_blame(struct scoreboard *sb, struct blame_entry *blamed)
1397 {
1398         blamed = blame_sort(blamed, compare_blame_suspect);
1399         while (blamed)
1400         {
1401                 struct origin *porigin = blamed->suspect;
1402                 struct blame_entry *suspects = NULL;
1403                 do {
1404                         struct blame_entry *next = blamed->next;
1405                         blamed->next = suspects;
1406                         suspects = blamed;
1407                         blamed = next;
1408                 } while (blamed && blamed->suspect == porigin);
1409                 suspects = reverse_blame(suspects, NULL);
1410                 queue_blames(sb, porigin, suspects);
1411         }
1412 }
1413
1414 #define MAXSG 16
1415
1416 static void pass_blame(struct scoreboard *sb, struct origin *origin, int opt)
1417 {
1418         struct rev_info *revs = sb->revs;
1419         int i, pass, num_sg;
1420         struct commit *commit = origin->commit;
1421         struct commit_list *sg;
1422         struct origin *sg_buf[MAXSG];
1423         struct origin *porigin, **sg_origin = sg_buf;
1424         struct blame_entry *toosmall = NULL;
1425         struct blame_entry *blames, **blametail = &blames;
1426
1427         num_sg = num_scapegoats(revs, commit);
1428         if (!num_sg)
1429                 goto finish;
1430         else if (num_sg < ARRAY_SIZE(sg_buf))
1431                 memset(sg_buf, 0, sizeof(sg_buf));
1432         else
1433                 sg_origin = xcalloc(num_sg, sizeof(*sg_origin));
1434
1435         /*
1436          * The first pass looks for unrenamed path to optimize for
1437          * common cases, then we look for renames in the second pass.
1438          */
1439         for (pass = 0; pass < 2 - no_whole_file_rename; pass++) {
1440                 struct origin *(*find)(struct scoreboard *,
1441                                        struct commit *, struct origin *);
1442                 find = pass ? find_rename : find_origin;
1443
1444                 for (i = 0, sg = first_scapegoat(revs, commit);
1445                      i < num_sg && sg;
1446                      sg = sg->next, i++) {
1447                         struct commit *p = sg->item;
1448                         int j, same;
1449
1450                         if (sg_origin[i])
1451                                 continue;
1452                         if (parse_commit(p))
1453                                 continue;
1454                         porigin = find(sb, p, origin);
1455                         if (!porigin)
1456                                 continue;
1457                         if (!hashcmp(porigin->blob_sha1, origin->blob_sha1)) {
1458                                 pass_whole_blame(sb, origin, porigin);
1459                                 origin_decref(porigin);
1460                                 goto finish;
1461                         }
1462                         for (j = same = 0; j < i; j++)
1463                                 if (sg_origin[j] &&
1464                                     !hashcmp(sg_origin[j]->blob_sha1,
1465                                              porigin->blob_sha1)) {
1466                                         same = 1;
1467                                         break;
1468                                 }
1469                         if (!same)
1470                                 sg_origin[i] = porigin;
1471                         else
1472                                 origin_decref(porigin);
1473                 }
1474         }
1475
1476         num_commits++;
1477         for (i = 0, sg = first_scapegoat(revs, commit);
1478              i < num_sg && sg;
1479              sg = sg->next, i++) {
1480                 struct origin *porigin = sg_origin[i];
1481                 if (!porigin)
1482                         continue;
1483                 if (!origin->previous) {
1484                         origin_incref(porigin);
1485                         origin->previous = porigin;
1486                 }
1487                 pass_blame_to_parent(sb, origin, porigin);
1488                 if (!origin->suspects)
1489                         goto finish;
1490         }
1491
1492         /*
1493          * Optionally find moves in parents' files.
1494          */
1495         if (opt & PICKAXE_BLAME_MOVE) {
1496                 filter_small(sb, &toosmall, &origin->suspects, blame_move_score);
1497                 if (origin->suspects) {
1498                         for (i = 0, sg = first_scapegoat(revs, commit);
1499                              i < num_sg && sg;
1500                              sg = sg->next, i++) {
1501                                 struct origin *porigin = sg_origin[i];
1502                                 if (!porigin)
1503                                         continue;
1504                                 find_move_in_parent(sb, &blametail, &toosmall, origin, porigin);
1505                                 if (!origin->suspects)
1506                                         break;
1507                         }
1508                 }
1509         }
1510
1511         /*
1512          * Optionally find copies from parents' files.
1513          */
1514         if (opt & PICKAXE_BLAME_COPY) {
1515                 if (blame_copy_score > blame_move_score)
1516                         filter_small(sb, &toosmall, &origin->suspects, blame_copy_score);
1517                 else if (blame_copy_score < blame_move_score) {
1518                         origin->suspects = blame_merge(origin->suspects, toosmall);
1519                         toosmall = NULL;
1520                         filter_small(sb, &toosmall, &origin->suspects, blame_copy_score);
1521                 }
1522                 if (!origin->suspects)
1523                         goto finish;
1524
1525                 for (i = 0, sg = first_scapegoat(revs, commit);
1526                      i < num_sg && sg;
1527                      sg = sg->next, i++) {
1528                         struct origin *porigin = sg_origin[i];
1529                         find_copy_in_parent(sb, &blametail, &toosmall,
1530                                             origin, sg->item, porigin, opt);
1531                         if (!origin->suspects)
1532                                 goto finish;
1533                 }
1534         }
1535
1536 finish:
1537         *blametail = NULL;
1538         distribute_blame(sb, blames);
1539         /*
1540          * prepend toosmall to origin->suspects
1541          *
1542          * There is no point in sorting: this ends up on a big
1543          * unsorted list in the caller anyway.
1544          */
1545         if (toosmall) {
1546                 struct blame_entry **tail = &toosmall;
1547                 while (*tail)
1548                         tail = &(*tail)->next;
1549                 *tail = origin->suspects;
1550                 origin->suspects = toosmall;
1551         }
1552         for (i = 0; i < num_sg; i++) {
1553                 if (sg_origin[i]) {
1554                         drop_origin_blob(sg_origin[i]);
1555                         origin_decref(sg_origin[i]);
1556                 }
1557         }
1558         drop_origin_blob(origin);
1559         if (sg_buf != sg_origin)
1560                 free(sg_origin);
1561 }
1562
1563 /*
1564  * Information on commits, used for output.
1565  */
1566 struct commit_info {
1567         struct strbuf author;
1568         struct strbuf author_mail;
1569         unsigned long author_time;
1570         struct strbuf author_tz;
1571
1572         /* filled only when asked for details */
1573         struct strbuf committer;
1574         struct strbuf committer_mail;
1575         unsigned long committer_time;
1576         struct strbuf committer_tz;
1577
1578         struct strbuf summary;
1579 };
1580
1581 /*
1582  * Parse author/committer line in the commit object buffer
1583  */
1584 static void get_ac_line(const char *inbuf, const char *what,
1585         struct strbuf *name, struct strbuf *mail,
1586         unsigned long *time, struct strbuf *tz)
1587 {
1588         struct ident_split ident;
1589         size_t len, maillen, namelen;
1590         char *tmp, *endp;
1591         const char *namebuf, *mailbuf;
1592
1593         tmp = strstr(inbuf, what);
1594         if (!tmp)
1595                 goto error_out;
1596         tmp += strlen(what);
1597         endp = strchr(tmp, '\n');
1598         if (!endp)
1599                 len = strlen(tmp);
1600         else
1601                 len = endp - tmp;
1602
1603         if (split_ident_line(&ident, tmp, len)) {
1604         error_out:
1605                 /* Ugh */
1606                 tmp = "(unknown)";
1607                 strbuf_addstr(name, tmp);
1608                 strbuf_addstr(mail, tmp);
1609                 strbuf_addstr(tz, tmp);
1610                 *time = 0;
1611                 return;
1612         }
1613
1614         namelen = ident.name_end - ident.name_begin;
1615         namebuf = ident.name_begin;
1616
1617         maillen = ident.mail_end - ident.mail_begin;
1618         mailbuf = ident.mail_begin;
1619
1620         if (ident.date_begin && ident.date_end)
1621                 *time = strtoul(ident.date_begin, NULL, 10);
1622         else
1623                 *time = 0;
1624
1625         if (ident.tz_begin && ident.tz_end)
1626                 strbuf_add(tz, ident.tz_begin, ident.tz_end - ident.tz_begin);
1627         else
1628                 strbuf_addstr(tz, "(unknown)");
1629
1630         /*
1631          * Now, convert both name and e-mail using mailmap
1632          */
1633         map_user(&mailmap, &mailbuf, &maillen,
1634                  &namebuf, &namelen);
1635
1636         strbuf_addf(mail, "<%.*s>", (int)maillen, mailbuf);
1637         strbuf_add(name, namebuf, namelen);
1638 }
1639
1640 static void commit_info_init(struct commit_info *ci)
1641 {
1642
1643         strbuf_init(&ci->author, 0);
1644         strbuf_init(&ci->author_mail, 0);
1645         strbuf_init(&ci->author_tz, 0);
1646         strbuf_init(&ci->committer, 0);
1647         strbuf_init(&ci->committer_mail, 0);
1648         strbuf_init(&ci->committer_tz, 0);
1649         strbuf_init(&ci->summary, 0);
1650 }
1651
1652 static void commit_info_destroy(struct commit_info *ci)
1653 {
1654
1655         strbuf_release(&ci->author);
1656         strbuf_release(&ci->author_mail);
1657         strbuf_release(&ci->author_tz);
1658         strbuf_release(&ci->committer);
1659         strbuf_release(&ci->committer_mail);
1660         strbuf_release(&ci->committer_tz);
1661         strbuf_release(&ci->summary);
1662 }
1663
1664 static void get_commit_info(struct commit *commit,
1665                             struct commit_info *ret,
1666                             int detailed)
1667 {
1668         int len;
1669         const char *subject, *encoding;
1670         const char *message;
1671
1672         commit_info_init(ret);
1673
1674         encoding = get_log_output_encoding();
1675         message = logmsg_reencode(commit, NULL, encoding);
1676         get_ac_line(message, "\nauthor ",
1677                     &ret->author, &ret->author_mail,
1678                     &ret->author_time, &ret->author_tz);
1679
1680         if (!detailed) {
1681                 unuse_commit_buffer(commit, message);
1682                 return;
1683         }
1684
1685         get_ac_line(message, "\ncommitter ",
1686                     &ret->committer, &ret->committer_mail,
1687                     &ret->committer_time, &ret->committer_tz);
1688
1689         len = find_commit_subject(message, &subject);
1690         if (len)
1691                 strbuf_add(&ret->summary, subject, len);
1692         else
1693                 strbuf_addf(&ret->summary, "(%s)", sha1_to_hex(commit->object.sha1));
1694
1695         unuse_commit_buffer(commit, message);
1696 }
1697
1698 /*
1699  * To allow LF and other nonportable characters in pathnames,
1700  * they are c-style quoted as needed.
1701  */
1702 static void write_filename_info(const char *path)
1703 {
1704         printf("filename ");
1705         write_name_quoted(path, stdout, '\n');
1706 }
1707
1708 /*
1709  * Porcelain/Incremental format wants to show a lot of details per
1710  * commit.  Instead of repeating this every line, emit it only once,
1711  * the first time each commit appears in the output (unless the
1712  * user has specifically asked for us to repeat).
1713  */
1714 static int emit_one_suspect_detail(struct origin *suspect, int repeat)
1715 {
1716         struct commit_info ci;
1717
1718         if (!repeat && (suspect->commit->object.flags & METAINFO_SHOWN))
1719                 return 0;
1720
1721         suspect->commit->object.flags |= METAINFO_SHOWN;
1722         get_commit_info(suspect->commit, &ci, 1);
1723         printf("author %s\n", ci.author.buf);
1724         printf("author-mail %s\n", ci.author_mail.buf);
1725         printf("author-time %lu\n", ci.author_time);
1726         printf("author-tz %s\n", ci.author_tz.buf);
1727         printf("committer %s\n", ci.committer.buf);
1728         printf("committer-mail %s\n", ci.committer_mail.buf);
1729         printf("committer-time %lu\n", ci.committer_time);
1730         printf("committer-tz %s\n", ci.committer_tz.buf);
1731         printf("summary %s\n", ci.summary.buf);
1732         if (suspect->commit->object.flags & UNINTERESTING)
1733                 printf("boundary\n");
1734         if (suspect->previous) {
1735                 struct origin *prev = suspect->previous;
1736                 printf("previous %s ", sha1_to_hex(prev->commit->object.sha1));
1737                 write_name_quoted(prev->path, stdout, '\n');
1738         }
1739
1740         commit_info_destroy(&ci);
1741
1742         return 1;
1743 }
1744
1745 /*
1746  * The blame_entry is found to be guilty for the range.
1747  * Show it in incremental output.
1748  */
1749 static void found_guilty_entry(struct blame_entry *ent)
1750 {
1751         if (incremental) {
1752                 struct origin *suspect = ent->suspect;
1753
1754                 printf("%s %d %d %d\n",
1755                        sha1_to_hex(suspect->commit->object.sha1),
1756                        ent->s_lno + 1, ent->lno + 1, ent->num_lines);
1757                 emit_one_suspect_detail(suspect, 0);
1758                 write_filename_info(suspect->path);
1759                 maybe_flush_or_die(stdout, "stdout");
1760         }
1761 }
1762
1763 /*
1764  * The main loop -- while we have blobs with lines whose true origin
1765  * is still unknown, pick one blob, and allow its lines to pass blames
1766  * to its parents. */
1767 static void assign_blame(struct scoreboard *sb, int opt)
1768 {
1769         struct rev_info *revs = sb->revs;
1770         struct commit *commit = prio_queue_get(&sb->commits);
1771
1772         while (commit) {
1773                 struct blame_entry *ent;
1774                 struct origin *suspect = commit->util;
1775
1776                 /* find one suspect to break down */
1777                 while (suspect && !suspect->suspects)
1778                         suspect = suspect->next;
1779
1780                 if (!suspect) {
1781                         commit = prio_queue_get(&sb->commits);
1782                         continue;
1783                 }
1784
1785                 assert(commit == suspect->commit);
1786
1787                 /*
1788                  * We will use this suspect later in the loop,
1789                  * so hold onto it in the meantime.
1790                  */
1791                 origin_incref(suspect);
1792                 parse_commit(commit);
1793                 if (reverse ||
1794                     (!(commit->object.flags & UNINTERESTING) &&
1795                      !(revs->max_age != -1 && commit->date < revs->max_age)))
1796                         pass_blame(sb, suspect, opt);
1797                 else {
1798                         commit->object.flags |= UNINTERESTING;
1799                         if (commit->object.parsed)
1800                                 mark_parents_uninteresting(commit);
1801                 }
1802                 /* treat root commit as boundary */
1803                 if (!commit->parents && !show_root)
1804                         commit->object.flags |= UNINTERESTING;
1805
1806                 /* Take responsibility for the remaining entries */
1807                 ent = suspect->suspects;
1808                 if (ent) {
1809                         suspect->guilty = 1;
1810                         for (;;) {
1811                                 struct blame_entry *next = ent->next;
1812                                 found_guilty_entry(ent);
1813                                 if (next) {
1814                                         ent = next;
1815                                         continue;
1816                                 }
1817                                 ent->next = sb->ent;
1818                                 sb->ent = suspect->suspects;
1819                                 suspect->suspects = NULL;
1820                                 break;
1821                         }
1822                 }
1823                 origin_decref(suspect);
1824
1825                 if (DEBUG) /* sanity */
1826                         sanity_check_refcnt(sb);
1827         }
1828 }
1829
1830 static const char *format_time(unsigned long time, const char *tz_str,
1831                                int show_raw_time)
1832 {
1833         static struct strbuf time_buf = STRBUF_INIT;
1834
1835         strbuf_reset(&time_buf);
1836         if (show_raw_time) {
1837                 strbuf_addf(&time_buf, "%lu %s", time, tz_str);
1838         }
1839         else {
1840                 const char *time_str;
1841                 size_t time_width;
1842                 int tz;
1843                 tz = atoi(tz_str);
1844                 time_str = show_date(time, tz, &blame_date_mode);
1845                 strbuf_addstr(&time_buf, time_str);
1846                 /*
1847                  * Add space paddings to time_buf to display a fixed width
1848                  * string, and use time_width for display width calibration.
1849                  */
1850                 for (time_width = utf8_strwidth(time_str);
1851                      time_width < blame_date_width;
1852                      time_width++)
1853                         strbuf_addch(&time_buf, ' ');
1854         }
1855         return time_buf.buf;
1856 }
1857
1858 #define OUTPUT_ANNOTATE_COMPAT  001
1859 #define OUTPUT_LONG_OBJECT_NAME 002
1860 #define OUTPUT_RAW_TIMESTAMP    004
1861 #define OUTPUT_PORCELAIN        010
1862 #define OUTPUT_SHOW_NAME        020
1863 #define OUTPUT_SHOW_NUMBER      040
1864 #define OUTPUT_SHOW_SCORE      0100
1865 #define OUTPUT_NO_AUTHOR       0200
1866 #define OUTPUT_SHOW_EMAIL       0400
1867 #define OUTPUT_LINE_PORCELAIN 01000
1868
1869 static void emit_porcelain_details(struct origin *suspect, int repeat)
1870 {
1871         if (emit_one_suspect_detail(suspect, repeat) ||
1872             (suspect->commit->object.flags & MORE_THAN_ONE_PATH))
1873                 write_filename_info(suspect->path);
1874 }
1875
1876 static void emit_porcelain(struct scoreboard *sb, struct blame_entry *ent,
1877                            int opt)
1878 {
1879         int repeat = opt & OUTPUT_LINE_PORCELAIN;
1880         int cnt;
1881         const char *cp;
1882         struct origin *suspect = ent->suspect;
1883         char hex[GIT_SHA1_HEXSZ + 1];
1884
1885         sha1_to_hex_r(hex, suspect->commit->object.sha1);
1886         printf("%s %d %d %d\n",
1887                hex,
1888                ent->s_lno + 1,
1889                ent->lno + 1,
1890                ent->num_lines);
1891         emit_porcelain_details(suspect, repeat);
1892
1893         cp = nth_line(sb, ent->lno);
1894         for (cnt = 0; cnt < ent->num_lines; cnt++) {
1895                 char ch;
1896                 if (cnt) {
1897                         printf("%s %d %d\n", hex,
1898                                ent->s_lno + 1 + cnt,
1899                                ent->lno + 1 + cnt);
1900                         if (repeat)
1901                                 emit_porcelain_details(suspect, 1);
1902                 }
1903                 putchar('\t');
1904                 do {
1905                         ch = *cp++;
1906                         putchar(ch);
1907                 } while (ch != '\n' &&
1908                          cp < sb->final_buf + sb->final_buf_size);
1909         }
1910
1911         if (sb->final_buf_size && cp[-1] != '\n')
1912                 putchar('\n');
1913 }
1914
1915 static void emit_other(struct scoreboard *sb, struct blame_entry *ent, int opt)
1916 {
1917         int cnt;
1918         const char *cp;
1919         struct origin *suspect = ent->suspect;
1920         struct commit_info ci;
1921         char hex[GIT_SHA1_HEXSZ + 1];
1922         int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
1923
1924         get_commit_info(suspect->commit, &ci, 1);
1925         sha1_to_hex_r(hex, suspect->commit->object.sha1);
1926
1927         cp = nth_line(sb, ent->lno);
1928         for (cnt = 0; cnt < ent->num_lines; cnt++) {
1929                 char ch;
1930                 int length = (opt & OUTPUT_LONG_OBJECT_NAME) ? 40 : abbrev;
1931
1932                 if (suspect->commit->object.flags & UNINTERESTING) {
1933                         if (blank_boundary)
1934                                 memset(hex, ' ', length);
1935                         else if (!(opt & OUTPUT_ANNOTATE_COMPAT)) {
1936                                 length--;
1937                                 putchar('^');
1938                         }
1939                 }
1940
1941                 printf("%.*s", length, hex);
1942                 if (opt & OUTPUT_ANNOTATE_COMPAT) {
1943                         const char *name;
1944                         if (opt & OUTPUT_SHOW_EMAIL)
1945                                 name = ci.author_mail.buf;
1946                         else
1947                                 name = ci.author.buf;
1948                         printf("\t(%10s\t%10s\t%d)", name,
1949                                format_time(ci.author_time, ci.author_tz.buf,
1950                                            show_raw_time),
1951                                ent->lno + 1 + cnt);
1952                 } else {
1953                         if (opt & OUTPUT_SHOW_SCORE)
1954                                 printf(" %*d %02d",
1955                                        max_score_digits, ent->score,
1956                                        ent->suspect->refcnt);
1957                         if (opt & OUTPUT_SHOW_NAME)
1958                                 printf(" %-*.*s", longest_file, longest_file,
1959                                        suspect->path);
1960                         if (opt & OUTPUT_SHOW_NUMBER)
1961                                 printf(" %*d", max_orig_digits,
1962                                        ent->s_lno + 1 + cnt);
1963
1964                         if (!(opt & OUTPUT_NO_AUTHOR)) {
1965                                 const char *name;
1966                                 int pad;
1967                                 if (opt & OUTPUT_SHOW_EMAIL)
1968                                         name = ci.author_mail.buf;
1969                                 else
1970                                         name = ci.author.buf;
1971                                 pad = longest_author - utf8_strwidth(name);
1972                                 printf(" (%s%*s %10s",
1973                                        name, pad, "",
1974                                        format_time(ci.author_time,
1975                                                    ci.author_tz.buf,
1976                                                    show_raw_time));
1977                         }
1978                         printf(" %*d) ",
1979                                max_digits, ent->lno + 1 + cnt);
1980                 }
1981                 do {
1982                         ch = *cp++;
1983                         putchar(ch);
1984                 } while (ch != '\n' &&
1985                          cp < sb->final_buf + sb->final_buf_size);
1986         }
1987
1988         if (sb->final_buf_size && cp[-1] != '\n')
1989                 putchar('\n');
1990
1991         commit_info_destroy(&ci);
1992 }
1993
1994 static void output(struct scoreboard *sb, int option)
1995 {
1996         struct blame_entry *ent;
1997
1998         if (option & OUTPUT_PORCELAIN) {
1999                 for (ent = sb->ent; ent; ent = ent->next) {
2000                         int count = 0;
2001                         struct origin *suspect;
2002                         struct commit *commit = ent->suspect->commit;
2003                         if (commit->object.flags & MORE_THAN_ONE_PATH)
2004                                 continue;
2005                         for (suspect = commit->util; suspect; suspect = suspect->next) {
2006                                 if (suspect->guilty && count++) {
2007                                         commit->object.flags |= MORE_THAN_ONE_PATH;
2008                                         break;
2009                                 }
2010                         }
2011                 }
2012         }
2013
2014         for (ent = sb->ent; ent; ent = ent->next) {
2015                 if (option & OUTPUT_PORCELAIN)
2016                         emit_porcelain(sb, ent, option);
2017                 else {
2018                         emit_other(sb, ent, option);
2019                 }
2020         }
2021 }
2022
2023 static const char *get_next_line(const char *start, const char *end)
2024 {
2025         const char *nl = memchr(start, '\n', end - start);
2026         return nl ? nl + 1 : end;
2027 }
2028
2029 /*
2030  * To allow quick access to the contents of nth line in the
2031  * final image, prepare an index in the scoreboard.
2032  */
2033 static int prepare_lines(struct scoreboard *sb)
2034 {
2035         const char *buf = sb->final_buf;
2036         unsigned long len = sb->final_buf_size;
2037         const char *end = buf + len;
2038         const char *p;
2039         int *lineno;
2040         int num = 0;
2041
2042         for (p = buf; p < end; p = get_next_line(p, end))
2043                 num++;
2044
2045         sb->lineno = lineno = xmalloc(sizeof(*sb->lineno) * (num + 1));
2046
2047         for (p = buf; p < end; p = get_next_line(p, end))
2048                 *lineno++ = p - buf;
2049
2050         *lineno = len;
2051
2052         sb->num_lines = num;
2053         return sb->num_lines;
2054 }
2055
2056 /*
2057  * Add phony grafts for use with -S; this is primarily to
2058  * support git's cvsserver that wants to give a linear history
2059  * to its clients.
2060  */
2061 static int read_ancestry(const char *graft_file)
2062 {
2063         FILE *fp = fopen(graft_file, "r");
2064         struct strbuf buf = STRBUF_INIT;
2065         if (!fp)
2066                 return -1;
2067         while (!strbuf_getwholeline(&buf, fp, '\n')) {
2068                 /* The format is just "Commit Parent1 Parent2 ...\n" */
2069                 struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
2070                 if (graft)
2071                         register_commit_graft(graft, 0);
2072         }
2073         fclose(fp);
2074         strbuf_release(&buf);
2075         return 0;
2076 }
2077
2078 static int update_auto_abbrev(int auto_abbrev, struct origin *suspect)
2079 {
2080         const char *uniq = find_unique_abbrev(suspect->commit->object.sha1,
2081                                               auto_abbrev);
2082         int len = strlen(uniq);
2083         if (auto_abbrev < len)
2084                 return len;
2085         return auto_abbrev;
2086 }
2087
2088 /*
2089  * How many columns do we need to show line numbers, authors,
2090  * and filenames?
2091  */
2092 static void find_alignment(struct scoreboard *sb, int *option)
2093 {
2094         int longest_src_lines = 0;
2095         int longest_dst_lines = 0;
2096         unsigned largest_score = 0;
2097         struct blame_entry *e;
2098         int compute_auto_abbrev = (abbrev < 0);
2099         int auto_abbrev = default_abbrev;
2100
2101         for (e = sb->ent; e; e = e->next) {
2102                 struct origin *suspect = e->suspect;
2103                 int num;
2104
2105                 if (compute_auto_abbrev)
2106                         auto_abbrev = update_auto_abbrev(auto_abbrev, suspect);
2107                 if (strcmp(suspect->path, sb->path))
2108                         *option |= OUTPUT_SHOW_NAME;
2109                 num = strlen(suspect->path);
2110                 if (longest_file < num)
2111                         longest_file = num;
2112                 if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
2113                         struct commit_info ci;
2114                         suspect->commit->object.flags |= METAINFO_SHOWN;
2115                         get_commit_info(suspect->commit, &ci, 1);
2116                         if (*option & OUTPUT_SHOW_EMAIL)
2117                                 num = utf8_strwidth(ci.author_mail.buf);
2118                         else
2119                                 num = utf8_strwidth(ci.author.buf);
2120                         if (longest_author < num)
2121                                 longest_author = num;
2122                         commit_info_destroy(&ci);
2123                 }
2124                 num = e->s_lno + e->num_lines;
2125                 if (longest_src_lines < num)
2126                         longest_src_lines = num;
2127                 num = e->lno + e->num_lines;
2128                 if (longest_dst_lines < num)
2129                         longest_dst_lines = num;
2130                 if (largest_score < ent_score(sb, e))
2131                         largest_score = ent_score(sb, e);
2132         }
2133         max_orig_digits = decimal_width(longest_src_lines);
2134         max_digits = decimal_width(longest_dst_lines);
2135         max_score_digits = decimal_width(largest_score);
2136
2137         if (compute_auto_abbrev)
2138                 /* one more abbrev length is needed for the boundary commit */
2139                 abbrev = auto_abbrev + 1;
2140 }
2141
2142 /*
2143  * For debugging -- origin is refcounted, and this asserts that
2144  * we do not underflow.
2145  */
2146 static void sanity_check_refcnt(struct scoreboard *sb)
2147 {
2148         int baa = 0;
2149         struct blame_entry *ent;
2150
2151         for (ent = sb->ent; ent; ent = ent->next) {
2152                 /* Nobody should have zero or negative refcnt */
2153                 if (ent->suspect->refcnt <= 0) {
2154                         fprintf(stderr, "%s in %s has negative refcnt %d\n",
2155                                 ent->suspect->path,
2156                                 sha1_to_hex(ent->suspect->commit->object.sha1),
2157                                 ent->suspect->refcnt);
2158                         baa = 1;
2159                 }
2160         }
2161         if (baa) {
2162                 int opt = 0160;
2163                 find_alignment(sb, &opt);
2164                 output(sb, opt);
2165                 die("Baa %d!", baa);
2166         }
2167 }
2168
2169 static unsigned parse_score(const char *arg)
2170 {
2171         char *end;
2172         unsigned long score = strtoul(arg, &end, 10);
2173         if (*end)
2174                 return 0;
2175         return score;
2176 }
2177
2178 static const char *add_prefix(const char *prefix, const char *path)
2179 {
2180         return prefix_path(prefix, prefix ? strlen(prefix) : 0, path);
2181 }
2182
2183 static int git_blame_config(const char *var, const char *value, void *cb)
2184 {
2185         if (!strcmp(var, "blame.showroot")) {
2186                 show_root = git_config_bool(var, value);
2187                 return 0;
2188         }
2189         if (!strcmp(var, "blame.blankboundary")) {
2190                 blank_boundary = git_config_bool(var, value);
2191                 return 0;
2192         }
2193         if (!strcmp(var, "blame.showemail")) {
2194                 int *output_option = cb;
2195                 if (git_config_bool(var, value))
2196                         *output_option |= OUTPUT_SHOW_EMAIL;
2197                 else
2198                         *output_option &= ~OUTPUT_SHOW_EMAIL;
2199                 return 0;
2200         }
2201         if (!strcmp(var, "blame.date")) {
2202                 if (!value)
2203                         return config_error_nonbool(var);
2204                 parse_date_format(value, &blame_date_mode);
2205                 return 0;
2206         }
2207
2208         if (userdiff_config(var, value) < 0)
2209                 return -1;
2210
2211         return git_default_config(var, value, cb);
2212 }
2213
2214 static void verify_working_tree_path(struct commit *work_tree, const char *path)
2215 {
2216         struct commit_list *parents;
2217
2218         for (parents = work_tree->parents; parents; parents = parents->next) {
2219                 const unsigned char *commit_sha1 = parents->item->object.sha1;
2220                 unsigned char blob_sha1[20];
2221                 unsigned mode;
2222
2223                 if (!get_tree_entry(commit_sha1, path, blob_sha1, &mode) &&
2224                     sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
2225                         return;
2226         }
2227         die("no such path '%s' in HEAD", path);
2228 }
2229
2230 static struct commit_list **append_parent(struct commit_list **tail, const unsigned char *sha1)
2231 {
2232         struct commit *parent;
2233
2234         parent = lookup_commit_reference(sha1);
2235         if (!parent)
2236                 die("no such commit %s", sha1_to_hex(sha1));
2237         return &commit_list_insert(parent, tail)->next;
2238 }
2239
2240 static void append_merge_parents(struct commit_list **tail)
2241 {
2242         int merge_head;
2243         struct strbuf line = STRBUF_INIT;
2244
2245         merge_head = open(git_path_merge_head(), O_RDONLY);
2246         if (merge_head < 0) {
2247                 if (errno == ENOENT)
2248                         return;
2249                 die("cannot open '%s' for reading", git_path_merge_head());
2250         }
2251
2252         while (!strbuf_getwholeline_fd(&line, merge_head, '\n')) {
2253                 unsigned char sha1[20];
2254                 if (line.len < 40 || get_sha1_hex(line.buf, sha1))
2255                         die("unknown line in '%s': %s", git_path_merge_head(), line.buf);
2256                 tail = append_parent(tail, sha1);
2257         }
2258         close(merge_head);
2259         strbuf_release(&line);
2260 }
2261
2262 /*
2263  * This isn't as simple as passing sb->buf and sb->len, because we
2264  * want to transfer ownership of the buffer to the commit (so we
2265  * must use detach).
2266  */
2267 static void set_commit_buffer_from_strbuf(struct commit *c, struct strbuf *sb)
2268 {
2269         size_t len;
2270         void *buf = strbuf_detach(sb, &len);
2271         set_commit_buffer(c, buf, len);
2272 }
2273
2274 /*
2275  * Prepare a dummy commit that represents the work tree (or staged) item.
2276  * Note that annotating work tree item never works in the reverse.
2277  */
2278 static struct commit *fake_working_tree_commit(struct diff_options *opt,
2279                                                const char *path,
2280                                                const char *contents_from)
2281 {
2282         struct commit *commit;
2283         struct origin *origin;
2284         struct commit_list **parent_tail, *parent;
2285         unsigned char head_sha1[20];
2286         struct strbuf buf = STRBUF_INIT;
2287         const char *ident;
2288         time_t now;
2289         int size, len;
2290         struct cache_entry *ce;
2291         unsigned mode;
2292         struct strbuf msg = STRBUF_INIT;
2293
2294         time(&now);
2295         commit = alloc_commit_node();
2296         commit->object.parsed = 1;
2297         commit->date = now;
2298         parent_tail = &commit->parents;
2299
2300         if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
2301                 die("no such ref: HEAD");
2302
2303         parent_tail = append_parent(parent_tail, head_sha1);
2304         append_merge_parents(parent_tail);
2305         verify_working_tree_path(commit, path);
2306
2307         origin = make_origin(commit, path);
2308
2309         ident = fmt_ident("Not Committed Yet", "not.committed.yet", NULL, 0);
2310         strbuf_addstr(&msg, "tree 0000000000000000000000000000000000000000\n");
2311         for (parent = commit->parents; parent; parent = parent->next)
2312                 strbuf_addf(&msg, "parent %s\n",
2313                             sha1_to_hex(parent->item->object.sha1));
2314         strbuf_addf(&msg,
2315                     "author %s\n"
2316                     "committer %s\n\n"
2317                     "Version of %s from %s\n",
2318                     ident, ident, path,
2319                     (!contents_from ? path :
2320                      (!strcmp(contents_from, "-") ? "standard input" : contents_from)));
2321         set_commit_buffer_from_strbuf(commit, &msg);
2322
2323         if (!contents_from || strcmp("-", contents_from)) {
2324                 struct stat st;
2325                 const char *read_from;
2326                 char *buf_ptr;
2327                 unsigned long buf_len;
2328
2329                 if (contents_from) {
2330                         if (stat(contents_from, &st) < 0)
2331                                 die_errno("Cannot stat '%s'", contents_from);
2332                         read_from = contents_from;
2333                 }
2334                 else {
2335                         if (lstat(path, &st) < 0)
2336                                 die_errno("Cannot lstat '%s'", path);
2337                         read_from = path;
2338                 }
2339                 mode = canon_mode(st.st_mode);
2340
2341                 switch (st.st_mode & S_IFMT) {
2342                 case S_IFREG:
2343                         if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV) &&
2344                             textconv_object(read_from, mode, null_sha1, 0, &buf_ptr, &buf_len))
2345                                 strbuf_attach(&buf, buf_ptr, buf_len, buf_len + 1);
2346                         else if (strbuf_read_file(&buf, read_from, st.st_size) != st.st_size)
2347                                 die_errno("cannot open or read '%s'", read_from);
2348                         break;
2349                 case S_IFLNK:
2350                         if (strbuf_readlink(&buf, read_from, st.st_size) < 0)
2351                                 die_errno("cannot readlink '%s'", read_from);
2352                         break;
2353                 default:
2354                         die("unsupported file type %s", read_from);
2355                 }
2356         }
2357         else {
2358                 /* Reading from stdin */
2359                 mode = 0;
2360                 if (strbuf_read(&buf, 0, 0) < 0)
2361                         die_errno("failed to read from stdin");
2362         }
2363         convert_to_git(path, buf.buf, buf.len, &buf, 0);
2364         origin->file.ptr = buf.buf;
2365         origin->file.size = buf.len;
2366         pretend_sha1_file(buf.buf, buf.len, OBJ_BLOB, origin->blob_sha1);
2367
2368         /*
2369          * Read the current index, replace the path entry with
2370          * origin->blob_sha1 without mucking with its mode or type
2371          * bits; we are not going to write this index out -- we just
2372          * want to run "diff-index --cached".
2373          */
2374         discard_cache();
2375         read_cache();
2376
2377         len = strlen(path);
2378         if (!mode) {
2379                 int pos = cache_name_pos(path, len);
2380                 if (0 <= pos)
2381                         mode = active_cache[pos]->ce_mode;
2382                 else
2383                         /* Let's not bother reading from HEAD tree */
2384                         mode = S_IFREG | 0644;
2385         }
2386         size = cache_entry_size(len);
2387         ce = xcalloc(1, size);
2388         hashcpy(ce->sha1, origin->blob_sha1);
2389         memcpy(ce->name, path, len);
2390         ce->ce_flags = create_ce_flags(0);
2391         ce->ce_namelen = len;
2392         ce->ce_mode = create_ce_mode(mode);
2393         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
2394
2395         /*
2396          * We are not going to write this out, so this does not matter
2397          * right now, but someday we might optimize diff-index --cached
2398          * with cache-tree information.
2399          */
2400         cache_tree_invalidate_path(&the_index, path);
2401
2402         return commit;
2403 }
2404
2405 static struct object_array_entry *find_single_final(struct rev_info *revs)
2406 {
2407         int i;
2408         struct object_array_entry *found = NULL;
2409
2410         for (i = 0; i < revs->pending.nr; i++) {
2411                 struct object *obj = revs->pending.objects[i].item;
2412                 if (obj->flags & UNINTERESTING)
2413                         continue;
2414                 while (obj->type == OBJ_TAG)
2415                         obj = deref_tag(obj, NULL, 0);
2416                 if (obj->type != OBJ_COMMIT)
2417                         die("Non commit %s?", revs->pending.objects[i].name);
2418                 if (found)
2419                         die("More than one commit to dig from %s and %s?",
2420                             revs->pending.objects[i].name,
2421                             found->name);
2422                 found = &(revs->pending.objects[i]);
2423         }
2424         return found;
2425 }
2426
2427 static char *prepare_final(struct scoreboard *sb)
2428 {
2429         struct object_array_entry *found = find_single_final(sb->revs);
2430         if (found) {
2431                 sb->final = (struct commit *) found->item;
2432                 return xstrdup(found->name);
2433         } else {
2434                 return NULL;
2435         }
2436 }
2437
2438 static char *prepare_initial(struct scoreboard *sb)
2439 {
2440         int i;
2441         const char *final_commit_name = NULL;
2442         struct rev_info *revs = sb->revs;
2443
2444         /*
2445          * There must be one and only one negative commit, and it must be
2446          * the boundary.
2447          */
2448         for (i = 0; i < revs->pending.nr; i++) {
2449                 struct object *obj = revs->pending.objects[i].item;
2450                 if (!(obj->flags & UNINTERESTING))
2451                         continue;
2452                 while (obj->type == OBJ_TAG)
2453                         obj = deref_tag(obj, NULL, 0);
2454                 if (obj->type != OBJ_COMMIT)
2455                         die("Non commit %s?", revs->pending.objects[i].name);
2456                 if (sb->final)
2457                         die("More than one commit to dig down to %s and %s?",
2458                             revs->pending.objects[i].name,
2459                             final_commit_name);
2460                 sb->final = (struct commit *) obj;
2461                 final_commit_name = revs->pending.objects[i].name;
2462         }
2463         if (!final_commit_name)
2464                 die("No commit to dig down to?");
2465         return xstrdup(final_commit_name);
2466 }
2467
2468 static int blame_copy_callback(const struct option *option, const char *arg, int unset)
2469 {
2470         int *opt = option->value;
2471
2472         /*
2473          * -C enables copy from removed files;
2474          * -C -C enables copy from existing files, but only
2475          *       when blaming a new file;
2476          * -C -C -C enables copy from existing files for
2477          *          everybody
2478          */
2479         if (*opt & PICKAXE_BLAME_COPY_HARDER)
2480                 *opt |= PICKAXE_BLAME_COPY_HARDEST;
2481         if (*opt & PICKAXE_BLAME_COPY)
2482                 *opt |= PICKAXE_BLAME_COPY_HARDER;
2483         *opt |= PICKAXE_BLAME_COPY | PICKAXE_BLAME_MOVE;
2484
2485         if (arg)
2486                 blame_copy_score = parse_score(arg);
2487         return 0;
2488 }
2489
2490 static int blame_move_callback(const struct option *option, const char *arg, int unset)
2491 {
2492         int *opt = option->value;
2493
2494         *opt |= PICKAXE_BLAME_MOVE;
2495
2496         if (arg)
2497                 blame_move_score = parse_score(arg);
2498         return 0;
2499 }
2500
2501 int cmd_blame(int argc, const char **argv, const char *prefix)
2502 {
2503         struct rev_info revs;
2504         const char *path;
2505         struct scoreboard sb;
2506         struct origin *o;
2507         struct blame_entry *ent = NULL;
2508         long dashdash_pos, lno;
2509         char *final_commit_name = NULL;
2510         enum object_type type;
2511         struct commit *final_commit = NULL;
2512
2513         static struct string_list range_list;
2514         static int output_option = 0, opt = 0;
2515         static int show_stats = 0;
2516         static const char *revs_file = NULL;
2517         static const char *contents_from = NULL;
2518         static const struct option options[] = {
2519                 OPT_BOOL(0, "incremental", &incremental, N_("Show blame entries as we find them, incrementally")),
2520                 OPT_BOOL('b', NULL, &blank_boundary, N_("Show blank SHA-1 for boundary commits (Default: off)")),
2521                 OPT_BOOL(0, "root", &show_root, N_("Do not treat root commits as boundaries (Default: off)")),
2522                 OPT_BOOL(0, "show-stats", &show_stats, N_("Show work cost statistics")),
2523                 OPT_BIT(0, "score-debug", &output_option, N_("Show output score for blame entries"), OUTPUT_SHOW_SCORE),
2524                 OPT_BIT('f', "show-name", &output_option, N_("Show original filename (Default: auto)"), OUTPUT_SHOW_NAME),
2525                 OPT_BIT('n', "show-number", &output_option, N_("Show original linenumber (Default: off)"), OUTPUT_SHOW_NUMBER),
2526                 OPT_BIT('p', "porcelain", &output_option, N_("Show in a format designed for machine consumption"), OUTPUT_PORCELAIN),
2527                 OPT_BIT(0, "line-porcelain", &output_option, N_("Show porcelain format with per-line commit information"), OUTPUT_PORCELAIN|OUTPUT_LINE_PORCELAIN),
2528                 OPT_BIT('c', NULL, &output_option, N_("Use the same output mode as git-annotate (Default: off)"), OUTPUT_ANNOTATE_COMPAT),
2529                 OPT_BIT('t', NULL, &output_option, N_("Show raw timestamp (Default: off)"), OUTPUT_RAW_TIMESTAMP),
2530                 OPT_BIT('l', NULL, &output_option, N_("Show long commit SHA1 (Default: off)"), OUTPUT_LONG_OBJECT_NAME),
2531                 OPT_BIT('s', NULL, &output_option, N_("Suppress author name and timestamp (Default: off)"), OUTPUT_NO_AUTHOR),
2532                 OPT_BIT('e', "show-email", &output_option, N_("Show author email instead of name (Default: off)"), OUTPUT_SHOW_EMAIL),
2533                 OPT_BIT('w', NULL, &xdl_opts, N_("Ignore whitespace differences"), XDF_IGNORE_WHITESPACE),
2534                 OPT_BIT(0, "minimal", &xdl_opts, N_("Spend extra cycles to find better match"), XDF_NEED_MINIMAL),
2535                 OPT_STRING('S', NULL, &revs_file, N_("file"), N_("Use revisions from <file> instead of calling git-rev-list")),
2536                 OPT_STRING(0, "contents", &contents_from, N_("file"), N_("Use <file>'s contents as the final image")),
2537                 { OPTION_CALLBACK, 'C', NULL, &opt, N_("score"), N_("Find line copies within and across files"), PARSE_OPT_OPTARG, blame_copy_callback },
2538                 { OPTION_CALLBACK, 'M', NULL, &opt, N_("score"), N_("Find line movements within and across files"), PARSE_OPT_OPTARG, blame_move_callback },
2539                 OPT_STRING_LIST('L', NULL, &range_list, N_("n,m"), N_("Process only line range n,m, counting from 1")),
2540                 OPT__ABBREV(&abbrev),
2541                 OPT_END()
2542         };
2543
2544         struct parse_opt_ctx_t ctx;
2545         int cmd_is_annotate = !strcmp(argv[0], "annotate");
2546         struct range_set ranges;
2547         unsigned int range_i;
2548         long anchor;
2549
2550         git_config(git_blame_config, &output_option);
2551         init_revisions(&revs, NULL);
2552         revs.date_mode = blame_date_mode;
2553         DIFF_OPT_SET(&revs.diffopt, ALLOW_TEXTCONV);
2554         DIFF_OPT_SET(&revs.diffopt, FOLLOW_RENAMES);
2555
2556         save_commit_buffer = 0;
2557         dashdash_pos = 0;
2558
2559         parse_options_start(&ctx, argc, argv, prefix, options,
2560                             PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_ARGV0);
2561         for (;;) {
2562                 switch (parse_options_step(&ctx, options, blame_opt_usage)) {
2563                 case PARSE_OPT_HELP:
2564                         exit(129);
2565                 case PARSE_OPT_DONE:
2566                         if (ctx.argv[0])
2567                                 dashdash_pos = ctx.cpidx;
2568                         goto parse_done;
2569                 }
2570
2571                 if (!strcmp(ctx.argv[0], "--reverse")) {
2572                         ctx.argv[0] = "--children";
2573                         reverse = 1;
2574                 }
2575                 parse_revision_opt(&revs, &ctx, options, blame_opt_usage);
2576         }
2577 parse_done:
2578         no_whole_file_rename = !DIFF_OPT_TST(&revs.diffopt, FOLLOW_RENAMES);
2579         DIFF_OPT_CLR(&revs.diffopt, FOLLOW_RENAMES);
2580         argc = parse_options_end(&ctx);
2581
2582         if (0 < abbrev)
2583                 /* one more abbrev length is needed for the boundary commit */
2584                 abbrev++;
2585
2586         if (revs_file && read_ancestry(revs_file))
2587                 die_errno("reading graft file '%s' failed", revs_file);
2588
2589         if (cmd_is_annotate) {
2590                 output_option |= OUTPUT_ANNOTATE_COMPAT;
2591                 blame_date_mode.type = DATE_ISO8601;
2592         } else {
2593                 blame_date_mode = revs.date_mode;
2594         }
2595
2596         /* The maximum width used to show the dates */
2597         switch (blame_date_mode.type) {
2598         case DATE_RFC2822:
2599                 blame_date_width = sizeof("Thu, 19 Oct 2006 16:00:04 -0700");
2600                 break;
2601         case DATE_ISO8601_STRICT:
2602                 blame_date_width = sizeof("2006-10-19T16:00:04-07:00");
2603                 break;
2604         case DATE_ISO8601:
2605                 blame_date_width = sizeof("2006-10-19 16:00:04 -0700");
2606                 break;
2607         case DATE_RAW:
2608                 blame_date_width = sizeof("1161298804 -0700");
2609                 break;
2610         case DATE_SHORT:
2611                 blame_date_width = sizeof("2006-10-19");
2612                 break;
2613         case DATE_RELATIVE:
2614                 /* TRANSLATORS: This string is used to tell us the maximum
2615                    display width for a relative timestamp in "git blame"
2616                    output.  For C locale, "4 years, 11 months ago", which
2617                    takes 22 places, is the longest among various forms of
2618                    relative timestamps, but your language may need more or
2619                    fewer display columns. */
2620                 blame_date_width = utf8_strwidth(_("4 years, 11 months ago")) + 1; /* add the null */
2621                 break;
2622         case DATE_NORMAL:
2623                 blame_date_width = sizeof("Thu Oct 19 16:00:04 2006 -0700");
2624                 break;
2625         case DATE_STRFTIME:
2626                 blame_date_width = strlen(show_date(0, 0, &blame_date_mode)) + 1; /* add the null */
2627                 break;
2628         }
2629         blame_date_width -= 1; /* strip the null */
2630
2631         if (DIFF_OPT_TST(&revs.diffopt, FIND_COPIES_HARDER))
2632                 opt |= (PICKAXE_BLAME_COPY | PICKAXE_BLAME_MOVE |
2633                         PICKAXE_BLAME_COPY_HARDER);
2634
2635         if (!blame_move_score)
2636                 blame_move_score = BLAME_DEFAULT_MOVE_SCORE;
2637         if (!blame_copy_score)
2638                 blame_copy_score = BLAME_DEFAULT_COPY_SCORE;
2639
2640         /*
2641          * We have collected options unknown to us in argv[1..unk]
2642          * which are to be passed to revision machinery if we are
2643          * going to do the "bottom" processing.
2644          *
2645          * The remaining are:
2646          *
2647          * (1) if dashdash_pos != 0, it is either
2648          *     "blame [revisions] -- <path>" or
2649          *     "blame -- <path> <rev>"
2650          *
2651          * (2) otherwise, it is one of the two:
2652          *     "blame [revisions] <path>"
2653          *     "blame <path> <rev>"
2654          *
2655          * Note that we must strip out <path> from the arguments: we do not
2656          * want the path pruning but we may want "bottom" processing.
2657          */
2658         if (dashdash_pos) {
2659                 switch (argc - dashdash_pos - 1) {
2660                 case 2: /* (1b) */
2661                         if (argc != 4)
2662                                 usage_with_options(blame_opt_usage, options);
2663                         /* reorder for the new way: <rev> -- <path> */
2664                         argv[1] = argv[3];
2665                         argv[3] = argv[2];
2666                         argv[2] = "--";
2667                         /* FALLTHROUGH */
2668                 case 1: /* (1a) */
2669                         path = add_prefix(prefix, argv[--argc]);
2670                         argv[argc] = NULL;
2671                         break;
2672                 default:
2673                         usage_with_options(blame_opt_usage, options);
2674                 }
2675         } else {
2676                 if (argc < 2)
2677                         usage_with_options(blame_opt_usage, options);
2678                 path = add_prefix(prefix, argv[argc - 1]);
2679                 if (argc == 3 && !file_exists(path)) { /* (2b) */
2680                         path = add_prefix(prefix, argv[1]);
2681                         argv[1] = argv[2];
2682                 }
2683                 argv[argc - 1] = "--";
2684
2685                 setup_work_tree();
2686                 if (!file_exists(path))
2687                         die_errno("cannot stat path '%s'", path);
2688         }
2689
2690         revs.disable_stdin = 1;
2691         setup_revisions(argc, argv, &revs, NULL);
2692         memset(&sb, 0, sizeof(sb));
2693
2694         sb.revs = &revs;
2695         if (!reverse) {
2696                 final_commit_name = prepare_final(&sb);
2697                 sb.commits.compare = compare_commits_by_commit_date;
2698         }
2699         else if (contents_from)
2700                 die("--contents and --reverse do not blend well.");
2701         else {
2702                 final_commit_name = prepare_initial(&sb);
2703                 sb.commits.compare = compare_commits_by_reverse_commit_date;
2704                 if (revs.first_parent_only)
2705                         revs.children.name = NULL;
2706         }
2707
2708         if (!sb.final) {
2709                 /*
2710                  * "--not A B -- path" without anything positive;
2711                  * do not default to HEAD, but use the working tree
2712                  * or "--contents".
2713                  */
2714                 setup_work_tree();
2715                 sb.final = fake_working_tree_commit(&sb.revs->diffopt,
2716                                                     path, contents_from);
2717                 add_pending_object(&revs, &(sb.final->object), ":");
2718         }
2719         else if (contents_from)
2720                 die("Cannot use --contents with final commit object name");
2721
2722         if (reverse && revs.first_parent_only) {
2723                 struct object_array_entry *entry = find_single_final(sb.revs);
2724                 if (!entry)
2725                         die("--reverse and --first-parent together require specified latest commit");
2726                 else
2727                         final_commit = (struct commit*) entry->item;
2728         }
2729
2730         /*
2731          * If we have bottom, this will mark the ancestors of the
2732          * bottom commits we would reach while traversing as
2733          * uninteresting.
2734          */
2735         if (prepare_revision_walk(&revs))
2736                 die(_("revision walk setup failed"));
2737
2738         if (reverse && revs.first_parent_only) {
2739                 struct commit *c = final_commit;
2740
2741                 sb.revs->children.name = "children";
2742                 while (c->parents &&
2743                        hashcmp(c->object.sha1, sb.final->object.sha1)) {
2744                         struct commit_list *l = xcalloc(1, sizeof(*l));
2745
2746                         l->item = c;
2747                         if (add_decoration(&sb.revs->children,
2748                                            &c->parents->item->object, l))
2749                                 die("BUG: not unique item in first-parent chain");
2750                         c = c->parents->item;
2751                 }
2752
2753                 if (hashcmp(c->object.sha1, sb.final->object.sha1))
2754                         die("--reverse --first-parent together require range along first-parent chain");
2755         }
2756
2757         if (is_null_sha1(sb.final->object.sha1)) {
2758                 o = sb.final->util;
2759                 sb.final_buf = xmemdupz(o->file.ptr, o->file.size);
2760                 sb.final_buf_size = o->file.size;
2761         }
2762         else {
2763                 o = get_origin(&sb, sb.final, path);
2764                 if (fill_blob_sha1_and_mode(o))
2765                         die("no such path %s in %s", path, final_commit_name);
2766
2767                 if (DIFF_OPT_TST(&sb.revs->diffopt, ALLOW_TEXTCONV) &&
2768                     textconv_object(path, o->mode, o->blob_sha1, 1, (char **) &sb.final_buf,
2769                                     &sb.final_buf_size))
2770                         ;
2771                 else
2772                         sb.final_buf = read_sha1_file(o->blob_sha1, &type,
2773                                                       &sb.final_buf_size);
2774
2775                 if (!sb.final_buf)
2776                         die("Cannot read blob %s for path %s",
2777                             sha1_to_hex(o->blob_sha1),
2778                             path);
2779         }
2780         num_read_blob++;
2781         lno = prepare_lines(&sb);
2782
2783         if (lno && !range_list.nr)
2784                 string_list_append(&range_list, xstrdup("1"));
2785
2786         anchor = 1;
2787         range_set_init(&ranges, range_list.nr);
2788         for (range_i = 0; range_i < range_list.nr; ++range_i) {
2789                 long bottom, top;
2790                 if (parse_range_arg(range_list.items[range_i].string,
2791                                     nth_line_cb, &sb, lno, anchor,
2792                                     &bottom, &top, sb.path))
2793                         usage(blame_usage);
2794                 if (lno < top || ((lno || bottom) && lno < bottom))
2795                         die("file %s has only %lu lines", path, lno);
2796                 if (bottom < 1)
2797                         bottom = 1;
2798                 if (top < 1)
2799                         top = lno;
2800                 bottom--;
2801                 range_set_append_unsafe(&ranges, bottom, top);
2802                 anchor = top + 1;
2803         }
2804         sort_and_merge_range_set(&ranges);
2805
2806         for (range_i = ranges.nr; range_i > 0; --range_i) {
2807                 const struct range *r = &ranges.ranges[range_i - 1];
2808                 long bottom = r->start;
2809                 long top = r->end;
2810                 struct blame_entry *next = ent;
2811                 ent = xcalloc(1, sizeof(*ent));
2812                 ent->lno = bottom;
2813                 ent->num_lines = top - bottom;
2814                 ent->suspect = o;
2815                 ent->s_lno = bottom;
2816                 ent->next = next;
2817                 origin_incref(o);
2818         }
2819
2820         o->suspects = ent;
2821         prio_queue_put(&sb.commits, o->commit);
2822
2823         origin_decref(o);
2824
2825         range_set_release(&ranges);
2826         string_list_clear(&range_list, 0);
2827
2828         sb.ent = NULL;
2829         sb.path = path;
2830
2831         read_mailmap(&mailmap, NULL);
2832
2833         if (!incremental)
2834                 setup_pager();
2835
2836         assign_blame(&sb, opt);
2837
2838         free(final_commit_name);
2839
2840         if (incremental)
2841                 return 0;
2842
2843         sb.ent = blame_sort(sb.ent, compare_blame_final);
2844
2845         coalesce(&sb);
2846
2847         if (!(output_option & OUTPUT_PORCELAIN))
2848                 find_alignment(&sb, &output_option);
2849
2850         output(&sb, output_option);
2851         free((void *)sb.final_buf);
2852         for (ent = sb.ent; ent; ) {
2853                 struct blame_entry *e = ent->next;
2854                 free(ent);
2855                 ent = e;
2856         }
2857
2858         if (show_stats) {
2859                 printf("num read blob: %d\n", num_read_blob);
2860                 printf("num get patch: %d\n", num_get_patch);
2861                 printf("num commits: %d\n", num_commits);
2862         }
2863         return 0;
2864 }