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