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