fetch-pack: write shallow, then check connectivity
[git/git.git] / blame.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "cache-tree.h"
4 #include "mergesort.h"
5 #include "diff.h"
6 #include "diffcore.h"
7 #include "tag.h"
8 #include "blame.h"
9
10 void blame_origin_decref(struct blame_origin *o)
11 {
12 if (o && --o->refcnt <= 0) {
13 struct blame_origin *p, *l = NULL;
14 if (o->previous)
15 blame_origin_decref(o->previous);
16 free(o->file.ptr);
17 /* Should be present exactly once in commit chain */
18 for (p = o->commit->util; p; l = p, p = p->next) {
19 if (p == o) {
20 if (l)
21 l->next = p->next;
22 else
23 o->commit->util = p->next;
24 free(o);
25 return;
26 }
27 }
28 die("internal error in blame_origin_decref");
29 }
30 }
31
32 /*
33 * Given a commit and a path in it, create a new origin structure.
34 * The callers that add blame to the scoreboard should use
35 * get_origin() to obtain shared, refcounted copy instead of calling
36 * this function directly.
37 */
38 static struct blame_origin *make_origin(struct commit *commit, const char *path)
39 {
40 struct blame_origin *o;
41 FLEX_ALLOC_STR(o, path, path);
42 o->commit = commit;
43 o->refcnt = 1;
44 o->next = commit->util;
45 commit->util = o;
46 return o;
47 }
48
49 /*
50 * Locate an existing origin or create a new one.
51 * This moves the origin to front position in the commit util list.
52 */
53 static struct blame_origin *get_origin(struct commit *commit, const char *path)
54 {
55 struct blame_origin *o, *l;
56
57 for (o = commit->util, l = NULL; o; l = o, o = o->next) {
58 if (!strcmp(o->path, path)) {
59 /* bump to front */
60 if (l) {
61 l->next = o->next;
62 o->next = commit->util;
63 commit->util = o;
64 }
65 return blame_origin_incref(o);
66 }
67 }
68 return make_origin(commit, path);
69 }
70
71
72
73 static void verify_working_tree_path(struct commit *work_tree, const char *path)
74 {
75 struct commit_list *parents;
76 int pos;
77
78 for (parents = work_tree->parents; parents; parents = parents->next) {
79 const struct object_id *commit_oid = &parents->item->object.oid;
80 struct object_id blob_oid;
81 unsigned mode;
82
83 if (!get_tree_entry(commit_oid, path, &blob_oid, &mode) &&
84 oid_object_info(the_repository, &blob_oid, NULL) == OBJ_BLOB)
85 return;
86 }
87
88 pos = cache_name_pos(path, strlen(path));
89 if (pos >= 0)
90 ; /* path is in the index */
91 else if (-1 - pos < active_nr &&
92 !strcmp(active_cache[-1 - pos]->name, path))
93 ; /* path is in the index, unmerged */
94 else
95 die("no such path '%s' in HEAD", path);
96 }
97
98 static struct commit_list **append_parent(struct commit_list **tail, const struct object_id *oid)
99 {
100 struct commit *parent;
101
102 parent = lookup_commit_reference(oid);
103 if (!parent)
104 die("no such commit %s", oid_to_hex(oid));
105 return &commit_list_insert(parent, tail)->next;
106 }
107
108 static void append_merge_parents(struct commit_list **tail)
109 {
110 int merge_head;
111 struct strbuf line = STRBUF_INIT;
112
113 merge_head = open(git_path_merge_head(), O_RDONLY);
114 if (merge_head < 0) {
115 if (errno == ENOENT)
116 return;
117 die("cannot open '%s' for reading", git_path_merge_head());
118 }
119
120 while (!strbuf_getwholeline_fd(&line, merge_head, '\n')) {
121 struct object_id oid;
122 if (line.len < GIT_SHA1_HEXSZ || get_oid_hex(line.buf, &oid))
123 die("unknown line in '%s': %s", git_path_merge_head(), line.buf);
124 tail = append_parent(tail, &oid);
125 }
126 close(merge_head);
127 strbuf_release(&line);
128 }
129
130 /*
131 * This isn't as simple as passing sb->buf and sb->len, because we
132 * want to transfer ownership of the buffer to the commit (so we
133 * must use detach).
134 */
135 static void set_commit_buffer_from_strbuf(struct commit *c, struct strbuf *sb)
136 {
137 size_t len;
138 void *buf = strbuf_detach(sb, &len);
139 set_commit_buffer(c, buf, len);
140 }
141
142 /*
143 * Prepare a dummy commit that represents the work tree (or staged) item.
144 * Note that annotating work tree item never works in the reverse.
145 */
146 static struct commit *fake_working_tree_commit(struct diff_options *opt,
147 const char *path,
148 const char *contents_from)
149 {
150 struct commit *commit;
151 struct blame_origin *origin;
152 struct commit_list **parent_tail, *parent;
153 struct object_id head_oid;
154 struct strbuf buf = STRBUF_INIT;
155 const char *ident;
156 time_t now;
157 int size, len;
158 struct cache_entry *ce;
159 unsigned mode;
160 struct strbuf msg = STRBUF_INIT;
161
162 read_cache();
163 time(&now);
164 commit = alloc_commit_node();
165 commit->object.parsed = 1;
166 commit->date = now;
167 parent_tail = &commit->parents;
168
169 if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
170 die("no such ref: HEAD");
171
172 parent_tail = append_parent(parent_tail, &head_oid);
173 append_merge_parents(parent_tail);
174 verify_working_tree_path(commit, path);
175
176 origin = make_origin(commit, path);
177
178 ident = fmt_ident("Not Committed Yet", "not.committed.yet", NULL, 0);
179 strbuf_addstr(&msg, "tree 0000000000000000000000000000000000000000\n");
180 for (parent = commit->parents; parent; parent = parent->next)
181 strbuf_addf(&msg, "parent %s\n",
182 oid_to_hex(&parent->item->object.oid));
183 strbuf_addf(&msg,
184 "author %s\n"
185 "committer %s\n\n"
186 "Version of %s from %s\n",
187 ident, ident, path,
188 (!contents_from ? path :
189 (!strcmp(contents_from, "-") ? "standard input" : contents_from)));
190 set_commit_buffer_from_strbuf(commit, &msg);
191
192 if (!contents_from || strcmp("-", contents_from)) {
193 struct stat st;
194 const char *read_from;
195 char *buf_ptr;
196 unsigned long buf_len;
197
198 if (contents_from) {
199 if (stat(contents_from, &st) < 0)
200 die_errno("Cannot stat '%s'", contents_from);
201 read_from = contents_from;
202 }
203 else {
204 if (lstat(path, &st) < 0)
205 die_errno("Cannot lstat '%s'", path);
206 read_from = path;
207 }
208 mode = canon_mode(st.st_mode);
209
210 switch (st.st_mode & S_IFMT) {
211 case S_IFREG:
212 if (opt->flags.allow_textconv &&
213 textconv_object(read_from, mode, &null_oid, 0, &buf_ptr, &buf_len))
214 strbuf_attach(&buf, buf_ptr, buf_len, buf_len + 1);
215 else if (strbuf_read_file(&buf, read_from, st.st_size) != st.st_size)
216 die_errno("cannot open or read '%s'", read_from);
217 break;
218 case S_IFLNK:
219 if (strbuf_readlink(&buf, read_from, st.st_size) < 0)
220 die_errno("cannot readlink '%s'", read_from);
221 break;
222 default:
223 die("unsupported file type %s", read_from);
224 }
225 }
226 else {
227 /* Reading from stdin */
228 mode = 0;
229 if (strbuf_read(&buf, 0, 0) < 0)
230 die_errno("failed to read from stdin");
231 }
232 convert_to_git(&the_index, path, buf.buf, buf.len, &buf, 0);
233 origin->file.ptr = buf.buf;
234 origin->file.size = buf.len;
235 pretend_object_file(buf.buf, buf.len, OBJ_BLOB, &origin->blob_oid);
236
237 /*
238 * Read the current index, replace the path entry with
239 * origin->blob_sha1 without mucking with its mode or type
240 * bits; we are not going to write this index out -- we just
241 * want to run "diff-index --cached".
242 */
243 discard_cache();
244 read_cache();
245
246 len = strlen(path);
247 if (!mode) {
248 int pos = cache_name_pos(path, len);
249 if (0 <= pos)
250 mode = active_cache[pos]->ce_mode;
251 else
252 /* Let's not bother reading from HEAD tree */
253 mode = S_IFREG | 0644;
254 }
255 size = cache_entry_size(len);
256 ce = xcalloc(1, size);
257 oidcpy(&ce->oid, &origin->blob_oid);
258 memcpy(ce->name, path, len);
259 ce->ce_flags = create_ce_flags(0);
260 ce->ce_namelen = len;
261 ce->ce_mode = create_ce_mode(mode);
262 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
263
264 cache_tree_invalidate_path(&the_index, path);
265
266 return commit;
267 }
268
269
270
271 static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b,
272 xdl_emit_hunk_consume_func_t hunk_func, void *cb_data, int xdl_opts)
273 {
274 xpparam_t xpp = {0};
275 xdemitconf_t xecfg = {0};
276 xdemitcb_t ecb = {NULL};
277
278 xpp.flags = xdl_opts;
279 xecfg.hunk_func = hunk_func;
280 ecb.priv = cb_data;
281 return xdi_diff(file_a, file_b, &xpp, &xecfg, &ecb);
282 }
283
284 /*
285 * Given an origin, prepare mmfile_t structure to be used by the
286 * diff machinery
287 */
288 static void fill_origin_blob(struct diff_options *opt,
289 struct blame_origin *o, mmfile_t *file, int *num_read_blob)
290 {
291 if (!o->file.ptr) {
292 enum object_type type;
293 unsigned long file_size;
294
295 (*num_read_blob)++;
296 if (opt->flags.allow_textconv &&
297 textconv_object(o->path, o->mode, &o->blob_oid, 1, &file->ptr, &file_size))
298 ;
299 else
300 file->ptr = read_object_file(&o->blob_oid, &type,
301 &file_size);
302 file->size = file_size;
303
304 if (!file->ptr)
305 die("Cannot read blob %s for path %s",
306 oid_to_hex(&o->blob_oid),
307 o->path);
308 o->file = *file;
309 }
310 else
311 *file = o->file;
312 }
313
314 static void drop_origin_blob(struct blame_origin *o)
315 {
316 if (o->file.ptr) {
317 FREE_AND_NULL(o->file.ptr);
318 }
319 }
320
321 /*
322 * Any merge of blames happens on lists of blames that arrived via
323 * different parents in a single suspect. In this case, we want to
324 * sort according to the suspect line numbers as opposed to the final
325 * image line numbers. The function body is somewhat longish because
326 * it avoids unnecessary writes.
327 */
328
329 static struct blame_entry *blame_merge(struct blame_entry *list1,
330 struct blame_entry *list2)
331 {
332 struct blame_entry *p1 = list1, *p2 = list2,
333 **tail = &list1;
334
335 if (!p1)
336 return p2;
337 if (!p2)
338 return p1;
339
340 if (p1->s_lno <= p2->s_lno) {
341 do {
342 tail = &p1->next;
343 if ((p1 = *tail) == NULL) {
344 *tail = p2;
345 return list1;
346 }
347 } while (p1->s_lno <= p2->s_lno);
348 }
349 for (;;) {
350 *tail = p2;
351 do {
352 tail = &p2->next;
353 if ((p2 = *tail) == NULL) {
354 *tail = p1;
355 return list1;
356 }
357 } while (p1->s_lno > p2->s_lno);
358 *tail = p1;
359 do {
360 tail = &p1->next;
361 if ((p1 = *tail) == NULL) {
362 *tail = p2;
363 return list1;
364 }
365 } while (p1->s_lno <= p2->s_lno);
366 }
367 }
368
369 static void *get_next_blame(const void *p)
370 {
371 return ((struct blame_entry *)p)->next;
372 }
373
374 static void set_next_blame(void *p1, void *p2)
375 {
376 ((struct blame_entry *)p1)->next = p2;
377 }
378
379 /*
380 * Final image line numbers are all different, so we don't need a
381 * three-way comparison here.
382 */
383
384 static int compare_blame_final(const void *p1, const void *p2)
385 {
386 return ((struct blame_entry *)p1)->lno > ((struct blame_entry *)p2)->lno
387 ? 1 : -1;
388 }
389
390 static int compare_blame_suspect(const void *p1, const void *p2)
391 {
392 const struct blame_entry *s1 = p1, *s2 = p2;
393 /*
394 * to allow for collating suspects, we sort according to the
395 * respective pointer value as the primary sorting criterion.
396 * The actual relation is pretty unimportant as long as it
397 * establishes a total order. Comparing as integers gives us
398 * that.
399 */
400 if (s1->suspect != s2->suspect)
401 return (intptr_t)s1->suspect > (intptr_t)s2->suspect ? 1 : -1;
402 if (s1->s_lno == s2->s_lno)
403 return 0;
404 return s1->s_lno > s2->s_lno ? 1 : -1;
405 }
406
407 void blame_sort_final(struct blame_scoreboard *sb)
408 {
409 sb->ent = llist_mergesort(sb->ent, get_next_blame, set_next_blame,
410 compare_blame_final);
411 }
412
413 static int compare_commits_by_reverse_commit_date(const void *a,
414 const void *b,
415 void *c)
416 {
417 return -compare_commits_by_commit_date(a, b, c);
418 }
419
420 /*
421 * For debugging -- origin is refcounted, and this asserts that
422 * we do not underflow.
423 */
424 static void sanity_check_refcnt(struct blame_scoreboard *sb)
425 {
426 int baa = 0;
427 struct blame_entry *ent;
428
429 for (ent = sb->ent; ent; ent = ent->next) {
430 /* Nobody should have zero or negative refcnt */
431 if (ent->suspect->refcnt <= 0) {
432 fprintf(stderr, "%s in %s has negative refcnt %d\n",
433 ent->suspect->path,
434 oid_to_hex(&ent->suspect->commit->object.oid),
435 ent->suspect->refcnt);
436 baa = 1;
437 }
438 }
439 if (baa)
440 sb->on_sanity_fail(sb, baa);
441 }
442
443 /*
444 * If two blame entries that are next to each other came from
445 * contiguous lines in the same origin (i.e. <commit, path> pair),
446 * merge them together.
447 */
448 void blame_coalesce(struct blame_scoreboard *sb)
449 {
450 struct blame_entry *ent, *next;
451
452 for (ent = sb->ent; ent && (next = ent->next); ent = next) {
453 if (ent->suspect == next->suspect &&
454 ent->s_lno + ent->num_lines == next->s_lno) {
455 ent->num_lines += next->num_lines;
456 ent->next = next->next;
457 blame_origin_decref(next->suspect);
458 free(next);
459 ent->score = 0;
460 next = ent; /* again */
461 }
462 }
463
464 if (sb->debug) /* sanity */
465 sanity_check_refcnt(sb);
466 }
467
468 /*
469 * Merge the given sorted list of blames into a preexisting origin.
470 * If there were no previous blames to that commit, it is entered into
471 * the commit priority queue of the score board.
472 */
473
474 static void queue_blames(struct blame_scoreboard *sb, struct blame_origin *porigin,
475 struct blame_entry *sorted)
476 {
477 if (porigin->suspects)
478 porigin->suspects = blame_merge(porigin->suspects, sorted);
479 else {
480 struct blame_origin *o;
481 for (o = porigin->commit->util; o; o = o->next) {
482 if (o->suspects) {
483 porigin->suspects = sorted;
484 return;
485 }
486 }
487 porigin->suspects = sorted;
488 prio_queue_put(&sb->commits, porigin->commit);
489 }
490 }
491
492 /*
493 * Fill the blob_sha1 field of an origin if it hasn't, so that later
494 * call to fill_origin_blob() can use it to locate the data. blob_sha1
495 * for an origin is also used to pass the blame for the entire file to
496 * the parent to detect the case where a child's blob is identical to
497 * that of its parent's.
498 *
499 * This also fills origin->mode for corresponding tree path.
500 */
501 static int fill_blob_sha1_and_mode(struct blame_origin *origin)
502 {
503 if (!is_null_oid(&origin->blob_oid))
504 return 0;
505 if (get_tree_entry(&origin->commit->object.oid, origin->path, &origin->blob_oid, &origin->mode))
506 goto error_out;
507 if (oid_object_info(the_repository, &origin->blob_oid, NULL) != OBJ_BLOB)
508 goto error_out;
509 return 0;
510 error_out:
511 oidclr(&origin->blob_oid);
512 origin->mode = S_IFINVALID;
513 return -1;
514 }
515
516 /*
517 * We have an origin -- check if the same path exists in the
518 * parent and return an origin structure to represent it.
519 */
520 static struct blame_origin *find_origin(struct commit *parent,
521 struct blame_origin *origin)
522 {
523 struct blame_origin *porigin;
524 struct diff_options diff_opts;
525 const char *paths[2];
526
527 /* First check any existing origins */
528 for (porigin = parent->util; porigin; porigin = porigin->next)
529 if (!strcmp(porigin->path, origin->path)) {
530 /*
531 * The same path between origin and its parent
532 * without renaming -- the most common case.
533 */
534 return blame_origin_incref (porigin);
535 }
536
537 /* See if the origin->path is different between parent
538 * and origin first. Most of the time they are the
539 * same and diff-tree is fairly efficient about this.
540 */
541 diff_setup(&diff_opts);
542 diff_opts.flags.recursive = 1;
543 diff_opts.detect_rename = 0;
544 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
545 paths[0] = origin->path;
546 paths[1] = NULL;
547
548 parse_pathspec(&diff_opts.pathspec,
549 PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
550 PATHSPEC_LITERAL_PATH, "", paths);
551 diff_setup_done(&diff_opts);
552
553 if (is_null_oid(&origin->commit->object.oid))
554 do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
555 else
556 diff_tree_oid(get_commit_tree_oid(parent),
557 get_commit_tree_oid(origin->commit),
558 "", &diff_opts);
559 diffcore_std(&diff_opts);
560
561 if (!diff_queued_diff.nr) {
562 /* The path is the same as parent */
563 porigin = get_origin(parent, origin->path);
564 oidcpy(&porigin->blob_oid, &origin->blob_oid);
565 porigin->mode = origin->mode;
566 } else {
567 /*
568 * Since origin->path is a pathspec, if the parent
569 * commit had it as a directory, we will see a whole
570 * bunch of deletion of files in the directory that we
571 * do not care about.
572 */
573 int i;
574 struct diff_filepair *p = NULL;
575 for (i = 0; i < diff_queued_diff.nr; i++) {
576 const char *name;
577 p = diff_queued_diff.queue[i];
578 name = p->one->path ? p->one->path : p->two->path;
579 if (!strcmp(name, origin->path))
580 break;
581 }
582 if (!p)
583 die("internal error in blame::find_origin");
584 switch (p->status) {
585 default:
586 die("internal error in blame::find_origin (%c)",
587 p->status);
588 case 'M':
589 porigin = get_origin(parent, origin->path);
590 oidcpy(&porigin->blob_oid, &p->one->oid);
591 porigin->mode = p->one->mode;
592 break;
593 case 'A':
594 case 'T':
595 /* Did not exist in parent, or type changed */
596 break;
597 }
598 }
599 diff_flush(&diff_opts);
600 clear_pathspec(&diff_opts.pathspec);
601 return porigin;
602 }
603
604 /*
605 * We have an origin -- find the path that corresponds to it in its
606 * parent and return an origin structure to represent it.
607 */
608 static struct blame_origin *find_rename(struct commit *parent,
609 struct blame_origin *origin)
610 {
611 struct blame_origin *porigin = NULL;
612 struct diff_options diff_opts;
613 int i;
614
615 diff_setup(&diff_opts);
616 diff_opts.flags.recursive = 1;
617 diff_opts.detect_rename = DIFF_DETECT_RENAME;
618 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
619 diff_opts.single_follow = origin->path;
620 diff_setup_done(&diff_opts);
621
622 if (is_null_oid(&origin->commit->object.oid))
623 do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
624 else
625 diff_tree_oid(get_commit_tree_oid(parent),
626 get_commit_tree_oid(origin->commit),
627 "", &diff_opts);
628 diffcore_std(&diff_opts);
629
630 for (i = 0; i < diff_queued_diff.nr; i++) {
631 struct diff_filepair *p = diff_queued_diff.queue[i];
632 if ((p->status == 'R' || p->status == 'C') &&
633 !strcmp(p->two->path, origin->path)) {
634 porigin = get_origin(parent, p->one->path);
635 oidcpy(&porigin->blob_oid, &p->one->oid);
636 porigin->mode = p->one->mode;
637 break;
638 }
639 }
640 diff_flush(&diff_opts);
641 clear_pathspec(&diff_opts.pathspec);
642 return porigin;
643 }
644
645 /*
646 * Append a new blame entry to a given output queue.
647 */
648 static void add_blame_entry(struct blame_entry ***queue,
649 const struct blame_entry *src)
650 {
651 struct blame_entry *e = xmalloc(sizeof(*e));
652 memcpy(e, src, sizeof(*e));
653 blame_origin_incref(e->suspect);
654
655 e->next = **queue;
656 **queue = e;
657 *queue = &e->next;
658 }
659
660 /*
661 * src typically is on-stack; we want to copy the information in it to
662 * a malloced blame_entry that gets added to the given queue. The
663 * origin of dst loses a refcnt.
664 */
665 static void dup_entry(struct blame_entry ***queue,
666 struct blame_entry *dst, struct blame_entry *src)
667 {
668 blame_origin_incref(src->suspect);
669 blame_origin_decref(dst->suspect);
670 memcpy(dst, src, sizeof(*src));
671 dst->next = **queue;
672 **queue = dst;
673 *queue = &dst->next;
674 }
675
676 const char *blame_nth_line(struct blame_scoreboard *sb, long lno)
677 {
678 return sb->final_buf + sb->lineno[lno];
679 }
680
681 /*
682 * It is known that lines between tlno to same came from parent, and e
683 * has an overlap with that range. it also is known that parent's
684 * line plno corresponds to e's line tlno.
685 *
686 * <---- e ----->
687 * <------>
688 * <------------>
689 * <------------>
690 * <------------------>
691 *
692 * Split e into potentially three parts; before this chunk, the chunk
693 * to be blamed for the parent, and after that portion.
694 */
695 static void split_overlap(struct blame_entry *split,
696 struct blame_entry *e,
697 int tlno, int plno, int same,
698 struct blame_origin *parent)
699 {
700 int chunk_end_lno;
701 memset(split, 0, sizeof(struct blame_entry [3]));
702
703 if (e->s_lno < tlno) {
704 /* there is a pre-chunk part not blamed on parent */
705 split[0].suspect = blame_origin_incref(e->suspect);
706 split[0].lno = e->lno;
707 split[0].s_lno = e->s_lno;
708 split[0].num_lines = tlno - e->s_lno;
709 split[1].lno = e->lno + tlno - e->s_lno;
710 split[1].s_lno = plno;
711 }
712 else {
713 split[1].lno = e->lno;
714 split[1].s_lno = plno + (e->s_lno - tlno);
715 }
716
717 if (same < e->s_lno + e->num_lines) {
718 /* there is a post-chunk part not blamed on parent */
719 split[2].suspect = blame_origin_incref(e->suspect);
720 split[2].lno = e->lno + (same - e->s_lno);
721 split[2].s_lno = e->s_lno + (same - e->s_lno);
722 split[2].num_lines = e->s_lno + e->num_lines - same;
723 chunk_end_lno = split[2].lno;
724 }
725 else
726 chunk_end_lno = e->lno + e->num_lines;
727 split[1].num_lines = chunk_end_lno - split[1].lno;
728
729 /*
730 * if it turns out there is nothing to blame the parent for,
731 * forget about the splitting. !split[1].suspect signals this.
732 */
733 if (split[1].num_lines < 1)
734 return;
735 split[1].suspect = blame_origin_incref(parent);
736 }
737
738 /*
739 * split_overlap() divided an existing blame e into up to three parts
740 * in split. Any assigned blame is moved to queue to
741 * reflect the split.
742 */
743 static void split_blame(struct blame_entry ***blamed,
744 struct blame_entry ***unblamed,
745 struct blame_entry *split,
746 struct blame_entry *e)
747 {
748 if (split[0].suspect && split[2].suspect) {
749 /* The first part (reuse storage for the existing entry e) */
750 dup_entry(unblamed, e, &split[0]);
751
752 /* The last part -- me */
753 add_blame_entry(unblamed, &split[2]);
754
755 /* ... and the middle part -- parent */
756 add_blame_entry(blamed, &split[1]);
757 }
758 else if (!split[0].suspect && !split[2].suspect)
759 /*
760 * The parent covers the entire area; reuse storage for
761 * e and replace it with the parent.
762 */
763 dup_entry(blamed, e, &split[1]);
764 else if (split[0].suspect) {
765 /* me and then parent */
766 dup_entry(unblamed, e, &split[0]);
767 add_blame_entry(blamed, &split[1]);
768 }
769 else {
770 /* parent and then me */
771 dup_entry(blamed, e, &split[1]);
772 add_blame_entry(unblamed, &split[2]);
773 }
774 }
775
776 /*
777 * After splitting the blame, the origins used by the
778 * on-stack blame_entry should lose one refcnt each.
779 */
780 static void decref_split(struct blame_entry *split)
781 {
782 int i;
783
784 for (i = 0; i < 3; i++)
785 blame_origin_decref(split[i].suspect);
786 }
787
788 /*
789 * reverse_blame reverses the list given in head, appending tail.
790 * That allows us to build lists in reverse order, then reverse them
791 * afterwards. This can be faster than building the list in proper
792 * order right away. The reason is that building in proper order
793 * requires writing a link in the _previous_ element, while building
794 * in reverse order just requires placing the list head into the
795 * _current_ element.
796 */
797
798 static struct blame_entry *reverse_blame(struct blame_entry *head,
799 struct blame_entry *tail)
800 {
801 while (head) {
802 struct blame_entry *next = head->next;
803 head->next = tail;
804 tail = head;
805 head = next;
806 }
807 return tail;
808 }
809
810 /*
811 * Process one hunk from the patch between the current suspect for
812 * blame_entry e and its parent. This first blames any unfinished
813 * entries before the chunk (which is where target and parent start
814 * differing) on the parent, and then splits blame entries at the
815 * start and at the end of the difference region. Since use of -M and
816 * -C options may lead to overlapping/duplicate source line number
817 * ranges, all we can rely on from sorting/merging is the order of the
818 * first suspect line number.
819 */
820 static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
821 int tlno, int offset, int same,
822 struct blame_origin *parent)
823 {
824 struct blame_entry *e = **srcq;
825 struct blame_entry *samep = NULL, *diffp = NULL;
826
827 while (e && e->s_lno < tlno) {
828 struct blame_entry *next = e->next;
829 /*
830 * current record starts before differing portion. If
831 * it reaches into it, we need to split it up and
832 * examine the second part separately.
833 */
834 if (e->s_lno + e->num_lines > tlno) {
835 /* Move second half to a new record */
836 int len = tlno - e->s_lno;
837 struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
838 n->suspect = e->suspect;
839 n->lno = e->lno + len;
840 n->s_lno = e->s_lno + len;
841 n->num_lines = e->num_lines - len;
842 e->num_lines = len;
843 e->score = 0;
844 /* Push new record to diffp */
845 n->next = diffp;
846 diffp = n;
847 } else
848 blame_origin_decref(e->suspect);
849 /* Pass blame for everything before the differing
850 * chunk to the parent */
851 e->suspect = blame_origin_incref(parent);
852 e->s_lno += offset;
853 e->next = samep;
854 samep = e;
855 e = next;
856 }
857 /*
858 * As we don't know how much of a common stretch after this
859 * diff will occur, the currently blamed parts are all that we
860 * can assign to the parent for now.
861 */
862
863 if (samep) {
864 **dstq = reverse_blame(samep, **dstq);
865 *dstq = &samep->next;
866 }
867 /*
868 * Prepend the split off portions: everything after e starts
869 * after the blameable portion.
870 */
871 e = reverse_blame(diffp, e);
872
873 /*
874 * Now retain records on the target while parts are different
875 * from the parent.
876 */
877 samep = NULL;
878 diffp = NULL;
879 while (e && e->s_lno < same) {
880 struct blame_entry *next = e->next;
881
882 /*
883 * If current record extends into sameness, need to split.
884 */
885 if (e->s_lno + e->num_lines > same) {
886 /*
887 * Move second half to a new record to be
888 * processed by later chunks
889 */
890 int len = same - e->s_lno;
891 struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
892 n->suspect = blame_origin_incref(e->suspect);
893 n->lno = e->lno + len;
894 n->s_lno = e->s_lno + len;
895 n->num_lines = e->num_lines - len;
896 e->num_lines = len;
897 e->score = 0;
898 /* Push new record to samep */
899 n->next = samep;
900 samep = n;
901 }
902 e->next = diffp;
903 diffp = e;
904 e = next;
905 }
906 **srcq = reverse_blame(diffp, reverse_blame(samep, e));
907 /* Move across elements that are in the unblamable portion */
908 if (diffp)
909 *srcq = &diffp->next;
910 }
911
912 struct blame_chunk_cb_data {
913 struct blame_origin *parent;
914 long offset;
915 struct blame_entry **dstq;
916 struct blame_entry **srcq;
917 };
918
919 /* diff chunks are from parent to target */
920 static int blame_chunk_cb(long start_a, long count_a,
921 long start_b, long count_b, void *data)
922 {
923 struct blame_chunk_cb_data *d = data;
924 if (start_a - start_b != d->offset)
925 die("internal error in blame::blame_chunk_cb");
926 blame_chunk(&d->dstq, &d->srcq, start_b, start_a - start_b,
927 start_b + count_b, d->parent);
928 d->offset = start_a + count_a - (start_b + count_b);
929 return 0;
930 }
931
932 /*
933 * We are looking at the origin 'target' and aiming to pass blame
934 * for the lines it is suspected to its parent. Run diff to find
935 * which lines came from parent and pass blame for them.
936 */
937 static void pass_blame_to_parent(struct blame_scoreboard *sb,
938 struct blame_origin *target,
939 struct blame_origin *parent)
940 {
941 mmfile_t file_p, file_o;
942 struct blame_chunk_cb_data d;
943 struct blame_entry *newdest = NULL;
944
945 if (!target->suspects)
946 return; /* nothing remains for this target */
947
948 d.parent = parent;
949 d.offset = 0;
950 d.dstq = &newdest; d.srcq = &target->suspects;
951
952 fill_origin_blob(&sb->revs->diffopt, parent, &file_p, &sb->num_read_blob);
953 fill_origin_blob(&sb->revs->diffopt, target, &file_o, &sb->num_read_blob);
954 sb->num_get_patch++;
955
956 if (diff_hunks(&file_p, &file_o, blame_chunk_cb, &d, sb->xdl_opts))
957 die("unable to generate diff (%s -> %s)",
958 oid_to_hex(&parent->commit->object.oid),
959 oid_to_hex(&target->commit->object.oid));
960 /* The rest are the same as the parent */
961 blame_chunk(&d.dstq, &d.srcq, INT_MAX, d.offset, INT_MAX, parent);
962 *d.dstq = NULL;
963 queue_blames(sb, parent, newdest);
964
965 return;
966 }
967
968 /*
969 * The lines in blame_entry after splitting blames many times can become
970 * very small and trivial, and at some point it becomes pointless to
971 * blame the parents. E.g. "\t\t}\n\t}\n\n" appears everywhere in any
972 * ordinary C program, and it is not worth to say it was copied from
973 * totally unrelated file in the parent.
974 *
975 * Compute how trivial the lines in the blame_entry are.
976 */
977 unsigned blame_entry_score(struct blame_scoreboard *sb, struct blame_entry *e)
978 {
979 unsigned score;
980 const char *cp, *ep;
981
982 if (e->score)
983 return e->score;
984
985 score = 1;
986 cp = blame_nth_line(sb, e->lno);
987 ep = blame_nth_line(sb, e->lno + e->num_lines);
988 while (cp < ep) {
989 unsigned ch = *((unsigned char *)cp);
990 if (isalnum(ch))
991 score++;
992 cp++;
993 }
994 e->score = score;
995 return score;
996 }
997
998 /*
999 * best_so_far[] and potential[] are both a split of an existing blame_entry
1000 * that passes blame to the parent. Maintain best_so_far the best split so
1001 * far, by comparing potential and best_so_far and copying potential into
1002 * bst_so_far as needed.
1003 */
1004 static void copy_split_if_better(struct blame_scoreboard *sb,
1005 struct blame_entry *best_so_far,
1006 struct blame_entry *potential)
1007 {
1008 int i;
1009
1010 if (!potential[1].suspect)
1011 return;
1012 if (best_so_far[1].suspect) {
1013 if (blame_entry_score(sb, &potential[1]) <
1014 blame_entry_score(sb, &best_so_far[1]))
1015 return;
1016 }
1017
1018 for (i = 0; i < 3; i++)
1019 blame_origin_incref(potential[i].suspect);
1020 decref_split(best_so_far);
1021 memcpy(best_so_far, potential, sizeof(struct blame_entry[3]));
1022 }
1023
1024 /*
1025 * We are looking at a part of the final image represented by
1026 * ent (tlno and same are offset by ent->s_lno).
1027 * tlno is where we are looking at in the final image.
1028 * up to (but not including) same match preimage.
1029 * plno is where we are looking at in the preimage.
1030 *
1031 * <-------------- final image ---------------------->
1032 * <------ent------>
1033 * ^tlno ^same
1034 * <---------preimage----->
1035 * ^plno
1036 *
1037 * All line numbers are 0-based.
1038 */
1039 static void handle_split(struct blame_scoreboard *sb,
1040 struct blame_entry *ent,
1041 int tlno, int plno, int same,
1042 struct blame_origin *parent,
1043 struct blame_entry *split)
1044 {
1045 if (ent->num_lines <= tlno)
1046 return;
1047 if (tlno < same) {
1048 struct blame_entry potential[3];
1049 tlno += ent->s_lno;
1050 same += ent->s_lno;
1051 split_overlap(potential, ent, tlno, plno, same, parent);
1052 copy_split_if_better(sb, split, potential);
1053 decref_split(potential);
1054 }
1055 }
1056
1057 struct handle_split_cb_data {
1058 struct blame_scoreboard *sb;
1059 struct blame_entry *ent;
1060 struct blame_origin *parent;
1061 struct blame_entry *split;
1062 long plno;
1063 long tlno;
1064 };
1065
1066 static int handle_split_cb(long start_a, long count_a,
1067 long start_b, long count_b, void *data)
1068 {
1069 struct handle_split_cb_data *d = data;
1070 handle_split(d->sb, d->ent, d->tlno, d->plno, start_b, d->parent,
1071 d->split);
1072 d->plno = start_a + count_a;
1073 d->tlno = start_b + count_b;
1074 return 0;
1075 }
1076
1077 /*
1078 * Find the lines from parent that are the same as ent so that
1079 * we can pass blames to it. file_p has the blob contents for
1080 * the parent.
1081 */
1082 static void find_copy_in_blob(struct blame_scoreboard *sb,
1083 struct blame_entry *ent,
1084 struct blame_origin *parent,
1085 struct blame_entry *split,
1086 mmfile_t *file_p)
1087 {
1088 const char *cp;
1089 mmfile_t file_o;
1090 struct handle_split_cb_data d;
1091
1092 memset(&d, 0, sizeof(d));
1093 d.sb = sb; d.ent = ent; d.parent = parent; d.split = split;
1094 /*
1095 * Prepare mmfile that contains only the lines in ent.
1096 */
1097 cp = blame_nth_line(sb, ent->lno);
1098 file_o.ptr = (char *) cp;
1099 file_o.size = blame_nth_line(sb, ent->lno + ent->num_lines) - cp;
1100
1101 /*
1102 * file_o is a part of final image we are annotating.
1103 * file_p partially may match that image.
1104 */
1105 memset(split, 0, sizeof(struct blame_entry [3]));
1106 if (diff_hunks(file_p, &file_o, handle_split_cb, &d, sb->xdl_opts))
1107 die("unable to generate diff (%s)",
1108 oid_to_hex(&parent->commit->object.oid));
1109 /* remainder, if any, all match the preimage */
1110 handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split);
1111 }
1112
1113 /* Move all blame entries from list *source that have a score smaller
1114 * than score_min to the front of list *small.
1115 * Returns a pointer to the link pointing to the old head of the small list.
1116 */
1117
1118 static struct blame_entry **filter_small(struct blame_scoreboard *sb,
1119 struct blame_entry **small,
1120 struct blame_entry **source,
1121 unsigned score_min)
1122 {
1123 struct blame_entry *p = *source;
1124 struct blame_entry *oldsmall = *small;
1125 while (p) {
1126 if (blame_entry_score(sb, p) <= score_min) {
1127 *small = p;
1128 small = &p->next;
1129 p = *small;
1130 } else {
1131 *source = p;
1132 source = &p->next;
1133 p = *source;
1134 }
1135 }
1136 *small = oldsmall;
1137 *source = NULL;
1138 return small;
1139 }
1140
1141 /*
1142 * See if lines currently target is suspected for can be attributed to
1143 * parent.
1144 */
1145 static void find_move_in_parent(struct blame_scoreboard *sb,
1146 struct blame_entry ***blamed,
1147 struct blame_entry **toosmall,
1148 struct blame_origin *target,
1149 struct blame_origin *parent)
1150 {
1151 struct blame_entry *e, split[3];
1152 struct blame_entry *unblamed = target->suspects;
1153 struct blame_entry *leftover = NULL;
1154 mmfile_t file_p;
1155
1156 if (!unblamed)
1157 return; /* nothing remains for this target */
1158
1159 fill_origin_blob(&sb->revs->diffopt, parent, &file_p, &sb->num_read_blob);
1160 if (!file_p.ptr)
1161 return;
1162
1163 /* At each iteration, unblamed has a NULL-terminated list of
1164 * entries that have not yet been tested for blame. leftover
1165 * contains the reversed list of entries that have been tested
1166 * without being assignable to the parent.
1167 */
1168 do {
1169 struct blame_entry **unblamedtail = &unblamed;
1170 struct blame_entry *next;
1171 for (e = unblamed; e; e = next) {
1172 next = e->next;
1173 find_copy_in_blob(sb, e, parent, split, &file_p);
1174 if (split[1].suspect &&
1175 sb->move_score < blame_entry_score(sb, &split[1])) {
1176 split_blame(blamed, &unblamedtail, split, e);
1177 } else {
1178 e->next = leftover;
1179 leftover = e;
1180 }
1181 decref_split(split);
1182 }
1183 *unblamedtail = NULL;
1184 toosmall = filter_small(sb, toosmall, &unblamed, sb->move_score);
1185 } while (unblamed);
1186 target->suspects = reverse_blame(leftover, NULL);
1187 }
1188
1189 struct blame_list {
1190 struct blame_entry *ent;
1191 struct blame_entry split[3];
1192 };
1193
1194 /*
1195 * Count the number of entries the target is suspected for,
1196 * and prepare a list of entry and the best split.
1197 */
1198 static struct blame_list *setup_blame_list(struct blame_entry *unblamed,
1199 int *num_ents_p)
1200 {
1201 struct blame_entry *e;
1202 int num_ents, i;
1203 struct blame_list *blame_list = NULL;
1204
1205 for (e = unblamed, num_ents = 0; e; e = e->next)
1206 num_ents++;
1207 if (num_ents) {
1208 blame_list = xcalloc(num_ents, sizeof(struct blame_list));
1209 for (e = unblamed, i = 0; e; e = e->next)
1210 blame_list[i++].ent = e;
1211 }
1212 *num_ents_p = num_ents;
1213 return blame_list;
1214 }
1215
1216 /*
1217 * For lines target is suspected for, see if we can find code movement
1218 * across file boundary from the parent commit. porigin is the path
1219 * in the parent we already tried.
1220 */
1221 static void find_copy_in_parent(struct blame_scoreboard *sb,
1222 struct blame_entry ***blamed,
1223 struct blame_entry **toosmall,
1224 struct blame_origin *target,
1225 struct commit *parent,
1226 struct blame_origin *porigin,
1227 int opt)
1228 {
1229 struct diff_options diff_opts;
1230 int i, j;
1231 struct blame_list *blame_list;
1232 int num_ents;
1233 struct blame_entry *unblamed = target->suspects;
1234 struct blame_entry *leftover = NULL;
1235
1236 if (!unblamed)
1237 return; /* nothing remains for this target */
1238
1239 diff_setup(&diff_opts);
1240 diff_opts.flags.recursive = 1;
1241 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1242
1243 diff_setup_done(&diff_opts);
1244
1245 /* Try "find copies harder" on new path if requested;
1246 * we do not want to use diffcore_rename() actually to
1247 * match things up; find_copies_harder is set only to
1248 * force diff_tree_oid() to feed all filepairs to diff_queue,
1249 * and this code needs to be after diff_setup_done(), which
1250 * usually makes find-copies-harder imply copy detection.
1251 */
1252 if ((opt & PICKAXE_BLAME_COPY_HARDEST)
1253 || ((opt & PICKAXE_BLAME_COPY_HARDER)
1254 && (!porigin || strcmp(target->path, porigin->path))))
1255 diff_opts.flags.find_copies_harder = 1;
1256
1257 if (is_null_oid(&target->commit->object.oid))
1258 do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
1259 else
1260 diff_tree_oid(get_commit_tree_oid(parent),
1261 get_commit_tree_oid(target->commit),
1262 "", &diff_opts);
1263
1264 if (!diff_opts.flags.find_copies_harder)
1265 diffcore_std(&diff_opts);
1266
1267 do {
1268 struct blame_entry **unblamedtail = &unblamed;
1269 blame_list = setup_blame_list(unblamed, &num_ents);
1270
1271 for (i = 0; i < diff_queued_diff.nr; i++) {
1272 struct diff_filepair *p = diff_queued_diff.queue[i];
1273 struct blame_origin *norigin;
1274 mmfile_t file_p;
1275 struct blame_entry potential[3];
1276
1277 if (!DIFF_FILE_VALID(p->one))
1278 continue; /* does not exist in parent */
1279 if (S_ISGITLINK(p->one->mode))
1280 continue; /* ignore git links */
1281 if (porigin && !strcmp(p->one->path, porigin->path))
1282 /* find_move already dealt with this path */
1283 continue;
1284
1285 norigin = get_origin(parent, p->one->path);
1286 oidcpy(&norigin->blob_oid, &p->one->oid);
1287 norigin->mode = p->one->mode;
1288 fill_origin_blob(&sb->revs->diffopt, norigin, &file_p, &sb->num_read_blob);
1289 if (!file_p.ptr)
1290 continue;
1291
1292 for (j = 0; j < num_ents; j++) {
1293 find_copy_in_blob(sb, blame_list[j].ent,
1294 norigin, potential, &file_p);
1295 copy_split_if_better(sb, blame_list[j].split,
1296 potential);
1297 decref_split(potential);
1298 }
1299 blame_origin_decref(norigin);
1300 }
1301
1302 for (j = 0; j < num_ents; j++) {
1303 struct blame_entry *split = blame_list[j].split;
1304 if (split[1].suspect &&
1305 sb->copy_score < blame_entry_score(sb, &split[1])) {
1306 split_blame(blamed, &unblamedtail, split,
1307 blame_list[j].ent);
1308 } else {
1309 blame_list[j].ent->next = leftover;
1310 leftover = blame_list[j].ent;
1311 }
1312 decref_split(split);
1313 }
1314 free(blame_list);
1315 *unblamedtail = NULL;
1316 toosmall = filter_small(sb, toosmall, &unblamed, sb->copy_score);
1317 } while (unblamed);
1318 target->suspects = reverse_blame(leftover, NULL);
1319 diff_flush(&diff_opts);
1320 clear_pathspec(&diff_opts.pathspec);
1321 }
1322
1323 /*
1324 * The blobs of origin and porigin exactly match, so everything
1325 * origin is suspected for can be blamed on the parent.
1326 */
1327 static void pass_whole_blame(struct blame_scoreboard *sb,
1328 struct blame_origin *origin, struct blame_origin *porigin)
1329 {
1330 struct blame_entry *e, *suspects;
1331
1332 if (!porigin->file.ptr && origin->file.ptr) {
1333 /* Steal its file */
1334 porigin->file = origin->file;
1335 origin->file.ptr = NULL;
1336 }
1337 suspects = origin->suspects;
1338 origin->suspects = NULL;
1339 for (e = suspects; e; e = e->next) {
1340 blame_origin_incref(porigin);
1341 blame_origin_decref(e->suspect);
1342 e->suspect = porigin;
1343 }
1344 queue_blames(sb, porigin, suspects);
1345 }
1346
1347 /*
1348 * We pass blame from the current commit to its parents. We keep saying
1349 * "parent" (and "porigin"), but what we mean is to find scapegoat to
1350 * exonerate ourselves.
1351 */
1352 static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit,
1353 int reverse)
1354 {
1355 if (!reverse) {
1356 if (revs->first_parent_only &&
1357 commit->parents &&
1358 commit->parents->next) {
1359 free_commit_list(commit->parents->next);
1360 commit->parents->next = NULL;
1361 }
1362 return commit->parents;
1363 }
1364 return lookup_decoration(&revs->children, &commit->object);
1365 }
1366
1367 static int num_scapegoats(struct rev_info *revs, struct commit *commit, int reverse)
1368 {
1369 struct commit_list *l = first_scapegoat(revs, commit, reverse);
1370 return commit_list_count(l);
1371 }
1372
1373 /* Distribute collected unsorted blames to the respected sorted lists
1374 * in the various origins.
1375 */
1376 static void distribute_blame(struct blame_scoreboard *sb, struct blame_entry *blamed)
1377 {
1378 blamed = llist_mergesort(blamed, get_next_blame, set_next_blame,
1379 compare_blame_suspect);
1380 while (blamed)
1381 {
1382 struct blame_origin *porigin = blamed->suspect;
1383 struct blame_entry *suspects = NULL;
1384 do {
1385 struct blame_entry *next = blamed->next;
1386 blamed->next = suspects;
1387 suspects = blamed;
1388 blamed = next;
1389 } while (blamed && blamed->suspect == porigin);
1390 suspects = reverse_blame(suspects, NULL);
1391 queue_blames(sb, porigin, suspects);
1392 }
1393 }
1394
1395 #define MAXSG 16
1396
1397 static void pass_blame(struct blame_scoreboard *sb, struct blame_origin *origin, int opt)
1398 {
1399 struct rev_info *revs = sb->revs;
1400 int i, pass, num_sg;
1401 struct commit *commit = origin->commit;
1402 struct commit_list *sg;
1403 struct blame_origin *sg_buf[MAXSG];
1404 struct blame_origin *porigin, **sg_origin = sg_buf;
1405 struct blame_entry *toosmall = NULL;
1406 struct blame_entry *blames, **blametail = &blames;
1407
1408 num_sg = num_scapegoats(revs, commit, sb->reverse);
1409 if (!num_sg)
1410 goto finish;
1411 else if (num_sg < ARRAY_SIZE(sg_buf))
1412 memset(sg_buf, 0, sizeof(sg_buf));
1413 else
1414 sg_origin = xcalloc(num_sg, sizeof(*sg_origin));
1415
1416 /*
1417 * The first pass looks for unrenamed path to optimize for
1418 * common cases, then we look for renames in the second pass.
1419 */
1420 for (pass = 0; pass < 2 - sb->no_whole_file_rename; pass++) {
1421 struct blame_origin *(*find)(struct commit *, struct blame_origin *);
1422 find = pass ? find_rename : find_origin;
1423
1424 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1425 i < num_sg && sg;
1426 sg = sg->next, i++) {
1427 struct commit *p = sg->item;
1428 int j, same;
1429
1430 if (sg_origin[i])
1431 continue;
1432 if (parse_commit(p))
1433 continue;
1434 porigin = find(p, origin);
1435 if (!porigin)
1436 continue;
1437 if (!oidcmp(&porigin->blob_oid, &origin->blob_oid)) {
1438 pass_whole_blame(sb, origin, porigin);
1439 blame_origin_decref(porigin);
1440 goto finish;
1441 }
1442 for (j = same = 0; j < i; j++)
1443 if (sg_origin[j] &&
1444 !oidcmp(&sg_origin[j]->blob_oid, &porigin->blob_oid)) {
1445 same = 1;
1446 break;
1447 }
1448 if (!same)
1449 sg_origin[i] = porigin;
1450 else
1451 blame_origin_decref(porigin);
1452 }
1453 }
1454
1455 sb->num_commits++;
1456 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1457 i < num_sg && sg;
1458 sg = sg->next, i++) {
1459 struct blame_origin *porigin = sg_origin[i];
1460 if (!porigin)
1461 continue;
1462 if (!origin->previous) {
1463 blame_origin_incref(porigin);
1464 origin->previous = porigin;
1465 }
1466 pass_blame_to_parent(sb, origin, porigin);
1467 if (!origin->suspects)
1468 goto finish;
1469 }
1470
1471 /*
1472 * Optionally find moves in parents' files.
1473 */
1474 if (opt & PICKAXE_BLAME_MOVE) {
1475 filter_small(sb, &toosmall, &origin->suspects, sb->move_score);
1476 if (origin->suspects) {
1477 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1478 i < num_sg && sg;
1479 sg = sg->next, i++) {
1480 struct blame_origin *porigin = sg_origin[i];
1481 if (!porigin)
1482 continue;
1483 find_move_in_parent(sb, &blametail, &toosmall, origin, porigin);
1484 if (!origin->suspects)
1485 break;
1486 }
1487 }
1488 }
1489
1490 /*
1491 * Optionally find copies from parents' files.
1492 */
1493 if (opt & PICKAXE_BLAME_COPY) {
1494 if (sb->copy_score > sb->move_score)
1495 filter_small(sb, &toosmall, &origin->suspects, sb->copy_score);
1496 else if (sb->copy_score < sb->move_score) {
1497 origin->suspects = blame_merge(origin->suspects, toosmall);
1498 toosmall = NULL;
1499 filter_small(sb, &toosmall, &origin->suspects, sb->copy_score);
1500 }
1501 if (!origin->suspects)
1502 goto finish;
1503
1504 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1505 i < num_sg && sg;
1506 sg = sg->next, i++) {
1507 struct blame_origin *porigin = sg_origin[i];
1508 find_copy_in_parent(sb, &blametail, &toosmall,
1509 origin, sg->item, porigin, opt);
1510 if (!origin->suspects)
1511 goto finish;
1512 }
1513 }
1514
1515 finish:
1516 *blametail = NULL;
1517 distribute_blame(sb, blames);
1518 /*
1519 * prepend toosmall to origin->suspects
1520 *
1521 * There is no point in sorting: this ends up on a big
1522 * unsorted list in the caller anyway.
1523 */
1524 if (toosmall) {
1525 struct blame_entry **tail = &toosmall;
1526 while (*tail)
1527 tail = &(*tail)->next;
1528 *tail = origin->suspects;
1529 origin->suspects = toosmall;
1530 }
1531 for (i = 0; i < num_sg; i++) {
1532 if (sg_origin[i]) {
1533 drop_origin_blob(sg_origin[i]);
1534 blame_origin_decref(sg_origin[i]);
1535 }
1536 }
1537 drop_origin_blob(origin);
1538 if (sg_buf != sg_origin)
1539 free(sg_origin);
1540 }
1541
1542 /*
1543 * The main loop -- while we have blobs with lines whose true origin
1544 * is still unknown, pick one blob, and allow its lines to pass blames
1545 * to its parents. */
1546 void assign_blame(struct blame_scoreboard *sb, int opt)
1547 {
1548 struct rev_info *revs = sb->revs;
1549 struct commit *commit = prio_queue_get(&sb->commits);
1550
1551 while (commit) {
1552 struct blame_entry *ent;
1553 struct blame_origin *suspect = commit->util;
1554
1555 /* find one suspect to break down */
1556 while (suspect && !suspect->suspects)
1557 suspect = suspect->next;
1558
1559 if (!suspect) {
1560 commit = prio_queue_get(&sb->commits);
1561 continue;
1562 }
1563
1564 assert(commit == suspect->commit);
1565
1566 /*
1567 * We will use this suspect later in the loop,
1568 * so hold onto it in the meantime.
1569 */
1570 blame_origin_incref(suspect);
1571 parse_commit(commit);
1572 if (sb->reverse ||
1573 (!(commit->object.flags & UNINTERESTING) &&
1574 !(revs->max_age != -1 && commit->date < revs->max_age)))
1575 pass_blame(sb, suspect, opt);
1576 else {
1577 commit->object.flags |= UNINTERESTING;
1578 if (commit->object.parsed)
1579 mark_parents_uninteresting(commit);
1580 }
1581 /* treat root commit as boundary */
1582 if (!commit->parents && !sb->show_root)
1583 commit->object.flags |= UNINTERESTING;
1584
1585 /* Take responsibility for the remaining entries */
1586 ent = suspect->suspects;
1587 if (ent) {
1588 suspect->guilty = 1;
1589 for (;;) {
1590 struct blame_entry *next = ent->next;
1591 if (sb->found_guilty_entry)
1592 sb->found_guilty_entry(ent, sb->found_guilty_entry_data);
1593 if (next) {
1594 ent = next;
1595 continue;
1596 }
1597 ent->next = sb->ent;
1598 sb->ent = suspect->suspects;
1599 suspect->suspects = NULL;
1600 break;
1601 }
1602 }
1603 blame_origin_decref(suspect);
1604
1605 if (sb->debug) /* sanity */
1606 sanity_check_refcnt(sb);
1607 }
1608 }
1609
1610 static const char *get_next_line(const char *start, const char *end)
1611 {
1612 const char *nl = memchr(start, '\n', end - start);
1613 return nl ? nl + 1 : end;
1614 }
1615
1616 /*
1617 * To allow quick access to the contents of nth line in the
1618 * final image, prepare an index in the scoreboard.
1619 */
1620 static int prepare_lines(struct blame_scoreboard *sb)
1621 {
1622 const char *buf = sb->final_buf;
1623 unsigned long len = sb->final_buf_size;
1624 const char *end = buf + len;
1625 const char *p;
1626 int *lineno;
1627 int num = 0;
1628
1629 for (p = buf; p < end; p = get_next_line(p, end))
1630 num++;
1631
1632 ALLOC_ARRAY(sb->lineno, num + 1);
1633 lineno = sb->lineno;
1634
1635 for (p = buf; p < end; p = get_next_line(p, end))
1636 *lineno++ = p - buf;
1637
1638 *lineno = len;
1639
1640 sb->num_lines = num;
1641 return sb->num_lines;
1642 }
1643
1644 static struct commit *find_single_final(struct rev_info *revs,
1645 const char **name_p)
1646 {
1647 int i;
1648 struct commit *found = NULL;
1649 const char *name = NULL;
1650
1651 for (i = 0; i < revs->pending.nr; i++) {
1652 struct object *obj = revs->pending.objects[i].item;
1653 if (obj->flags & UNINTERESTING)
1654 continue;
1655 obj = deref_tag(obj, NULL, 0);
1656 if (obj->type != OBJ_COMMIT)
1657 die("Non commit %s?", revs->pending.objects[i].name);
1658 if (found)
1659 die("More than one commit to dig from %s and %s?",
1660 revs->pending.objects[i].name, name);
1661 found = (struct commit *)obj;
1662 name = revs->pending.objects[i].name;
1663 }
1664 if (name_p)
1665 *name_p = xstrdup_or_null(name);
1666 return found;
1667 }
1668
1669 static struct commit *dwim_reverse_initial(struct rev_info *revs,
1670 const char **name_p)
1671 {
1672 /*
1673 * DWIM "git blame --reverse ONE -- PATH" as
1674 * "git blame --reverse ONE..HEAD -- PATH" but only do so
1675 * when it makes sense.
1676 */
1677 struct object *obj;
1678 struct commit *head_commit;
1679 struct object_id head_oid;
1680
1681 if (revs->pending.nr != 1)
1682 return NULL;
1683
1684 /* Is that sole rev a committish? */
1685 obj = revs->pending.objects[0].item;
1686 obj = deref_tag(obj, NULL, 0);
1687 if (obj->type != OBJ_COMMIT)
1688 return NULL;
1689
1690 /* Do we have HEAD? */
1691 if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
1692 return NULL;
1693 head_commit = lookup_commit_reference_gently(&head_oid, 1);
1694 if (!head_commit)
1695 return NULL;
1696
1697 /* Turn "ONE" into "ONE..HEAD" then */
1698 obj->flags |= UNINTERESTING;
1699 add_pending_object(revs, &head_commit->object, "HEAD");
1700
1701 if (name_p)
1702 *name_p = revs->pending.objects[0].name;
1703 return (struct commit *)obj;
1704 }
1705
1706 static struct commit *find_single_initial(struct rev_info *revs,
1707 const char **name_p)
1708 {
1709 int i;
1710 struct commit *found = NULL;
1711 const char *name = NULL;
1712
1713 /*
1714 * There must be one and only one negative commit, and it must be
1715 * the boundary.
1716 */
1717 for (i = 0; i < revs->pending.nr; i++) {
1718 struct object *obj = revs->pending.objects[i].item;
1719 if (!(obj->flags & UNINTERESTING))
1720 continue;
1721 obj = deref_tag(obj, NULL, 0);
1722 if (obj->type != OBJ_COMMIT)
1723 die("Non commit %s?", revs->pending.objects[i].name);
1724 if (found)
1725 die("More than one commit to dig up from, %s and %s?",
1726 revs->pending.objects[i].name, name);
1727 found = (struct commit *) obj;
1728 name = revs->pending.objects[i].name;
1729 }
1730
1731 if (!name)
1732 found = dwim_reverse_initial(revs, &name);
1733 if (!name)
1734 die("No commit to dig up from?");
1735
1736 if (name_p)
1737 *name_p = xstrdup(name);
1738 return found;
1739 }
1740
1741 void init_scoreboard(struct blame_scoreboard *sb)
1742 {
1743 memset(sb, 0, sizeof(struct blame_scoreboard));
1744 sb->move_score = BLAME_DEFAULT_MOVE_SCORE;
1745 sb->copy_score = BLAME_DEFAULT_COPY_SCORE;
1746 }
1747
1748 void setup_scoreboard(struct blame_scoreboard *sb, const char *path, struct blame_origin **orig)
1749 {
1750 const char *final_commit_name = NULL;
1751 struct blame_origin *o;
1752 struct commit *final_commit = NULL;
1753 enum object_type type;
1754
1755 if (sb->reverse && sb->contents_from)
1756 die(_("--contents and --reverse do not blend well."));
1757
1758 if (!sb->reverse) {
1759 sb->final = find_single_final(sb->revs, &final_commit_name);
1760 sb->commits.compare = compare_commits_by_commit_date;
1761 } else {
1762 sb->final = find_single_initial(sb->revs, &final_commit_name);
1763 sb->commits.compare = compare_commits_by_reverse_commit_date;
1764 }
1765
1766 if (sb->final && sb->contents_from)
1767 die(_("cannot use --contents with final commit object name"));
1768
1769 if (sb->reverse && sb->revs->first_parent_only)
1770 sb->revs->children.name = NULL;
1771
1772 if (!sb->final) {
1773 /*
1774 * "--not A B -- path" without anything positive;
1775 * do not default to HEAD, but use the working tree
1776 * or "--contents".
1777 */
1778 setup_work_tree();
1779 sb->final = fake_working_tree_commit(&sb->revs->diffopt,
1780 path, sb->contents_from);
1781 add_pending_object(sb->revs, &(sb->final->object), ":");
1782 }
1783
1784 if (sb->reverse && sb->revs->first_parent_only) {
1785 final_commit = find_single_final(sb->revs, NULL);
1786 if (!final_commit)
1787 die(_("--reverse and --first-parent together require specified latest commit"));
1788 }
1789
1790 /*
1791 * If we have bottom, this will mark the ancestors of the
1792 * bottom commits we would reach while traversing as
1793 * uninteresting.
1794 */
1795 if (prepare_revision_walk(sb->revs))
1796 die(_("revision walk setup failed"));
1797
1798 if (sb->reverse && sb->revs->first_parent_only) {
1799 struct commit *c = final_commit;
1800
1801 sb->revs->children.name = "children";
1802 while (c->parents &&
1803 oidcmp(&c->object.oid, &sb->final->object.oid)) {
1804 struct commit_list *l = xcalloc(1, sizeof(*l));
1805
1806 l->item = c;
1807 if (add_decoration(&sb->revs->children,
1808 &c->parents->item->object, l))
1809 BUG("not unique item in first-parent chain");
1810 c = c->parents->item;
1811 }
1812
1813 if (oidcmp(&c->object.oid, &sb->final->object.oid))
1814 die(_("--reverse --first-parent together require range along first-parent chain"));
1815 }
1816
1817 if (is_null_oid(&sb->final->object.oid)) {
1818 o = sb->final->util;
1819 sb->final_buf = xmemdupz(o->file.ptr, o->file.size);
1820 sb->final_buf_size = o->file.size;
1821 }
1822 else {
1823 o = get_origin(sb->final, path);
1824 if (fill_blob_sha1_and_mode(o))
1825 die(_("no such path %s in %s"), path, final_commit_name);
1826
1827 if (sb->revs->diffopt.flags.allow_textconv &&
1828 textconv_object(path, o->mode, &o->blob_oid, 1, (char **) &sb->final_buf,
1829 &sb->final_buf_size))
1830 ;
1831 else
1832 sb->final_buf = read_object_file(&o->blob_oid, &type,
1833 &sb->final_buf_size);
1834
1835 if (!sb->final_buf)
1836 die(_("cannot read blob %s for path %s"),
1837 oid_to_hex(&o->blob_oid),
1838 path);
1839 }
1840 sb->num_read_blob++;
1841 prepare_lines(sb);
1842
1843 if (orig)
1844 *orig = o;
1845
1846 free((char *)final_commit_name);
1847 }
1848
1849
1850
1851 struct blame_entry *blame_entry_prepend(struct blame_entry *head,
1852 long start, long end,
1853 struct blame_origin *o)
1854 {
1855 struct blame_entry *new_head = xcalloc(1, sizeof(struct blame_entry));
1856 new_head->lno = start;
1857 new_head->num_lines = end - start;
1858 new_head->suspect = o;
1859 new_head->s_lno = start;
1860 new_head->next = head;
1861 blame_origin_incref(o);
1862 return new_head;
1863 }