Merge branch 'ss/get-time-cleanup'
[git/git.git] / blame.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "object-store.h"
4 #include "cache-tree.h"
5 #include "mergesort.h"
6 #include "diff.h"
7 #include "diffcore.h"
8 #include "tag.h"
9 #include "blame.h"
10 #include "alloc.h"
11 #include "commit-slab.h"
12
13 define_commit_slab(blame_suspects, struct blame_origin *);
14 static struct blame_suspects blame_suspects;
15
16 struct blame_origin *get_blame_suspects(struct commit *commit)
17 {
18 struct blame_origin **result;
19
20 result = blame_suspects_peek(&blame_suspects, commit);
21
22 return result ? *result : NULL;
23 }
24
25 static void set_blame_suspects(struct commit *commit, struct blame_origin *origin)
26 {
27 *blame_suspects_at(&blame_suspects, commit) = origin;
28 }
29
30 void blame_origin_decref(struct blame_origin *o)
31 {
32 if (o && --o->refcnt <= 0) {
33 struct blame_origin *p, *l = NULL;
34 if (o->previous)
35 blame_origin_decref(o->previous);
36 free(o->file.ptr);
37 /* Should be present exactly once in commit chain */
38 for (p = get_blame_suspects(o->commit); p; l = p, p = p->next) {
39 if (p == o) {
40 if (l)
41 l->next = p->next;
42 else
43 set_blame_suspects(o->commit, p->next);
44 free(o);
45 return;
46 }
47 }
48 die("internal error in blame_origin_decref");
49 }
50 }
51
52 /*
53 * Given a commit and a path in it, create a new origin structure.
54 * The callers that add blame to the scoreboard should use
55 * get_origin() to obtain shared, refcounted copy instead of calling
56 * this function directly.
57 */
58 static struct blame_origin *make_origin(struct commit *commit, const char *path)
59 {
60 struct blame_origin *o;
61 FLEX_ALLOC_STR(o, path, path);
62 o->commit = commit;
63 o->refcnt = 1;
64 o->next = get_blame_suspects(commit);
65 set_blame_suspects(commit, o);
66 return o;
67 }
68
69 /*
70 * Locate an existing origin or create a new one.
71 * This moves the origin to front position in the commit util list.
72 */
73 static struct blame_origin *get_origin(struct commit *commit, const char *path)
74 {
75 struct blame_origin *o, *l;
76
77 for (o = get_blame_suspects(commit), l = NULL; o; l = o, o = o->next) {
78 if (!strcmp(o->path, path)) {
79 /* bump to front */
80 if (l) {
81 l->next = o->next;
82 o->next = get_blame_suspects(commit);
83 set_blame_suspects(commit, o);
84 }
85 return blame_origin_incref(o);
86 }
87 }
88 return make_origin(commit, path);
89 }
90
91
92
93 static void verify_working_tree_path(struct repository *r,
94 struct commit *work_tree, const char *path)
95 {
96 struct commit_list *parents;
97 int pos;
98
99 for (parents = work_tree->parents; parents; parents = parents->next) {
100 const struct object_id *commit_oid = &parents->item->object.oid;
101 struct object_id blob_oid;
102 unsigned short mode;
103
104 if (!get_tree_entry(r, commit_oid, path, &blob_oid, &mode) &&
105 oid_object_info(r, &blob_oid, NULL) == OBJ_BLOB)
106 return;
107 }
108
109 pos = index_name_pos(r->index, path, strlen(path));
110 if (pos >= 0)
111 ; /* path is in the index */
112 else if (-1 - pos < r->index->cache_nr &&
113 !strcmp(r->index->cache[-1 - pos]->name, path))
114 ; /* path is in the index, unmerged */
115 else
116 die("no such path '%s' in HEAD", path);
117 }
118
119 static struct commit_list **append_parent(struct repository *r,
120 struct commit_list **tail,
121 const struct object_id *oid)
122 {
123 struct commit *parent;
124
125 parent = lookup_commit_reference(r, oid);
126 if (!parent)
127 die("no such commit %s", oid_to_hex(oid));
128 return &commit_list_insert(parent, tail)->next;
129 }
130
131 static void append_merge_parents(struct repository *r,
132 struct commit_list **tail)
133 {
134 int merge_head;
135 struct strbuf line = STRBUF_INIT;
136
137 merge_head = open(git_path_merge_head(r), O_RDONLY);
138 if (merge_head < 0) {
139 if (errno == ENOENT)
140 return;
141 die("cannot open '%s' for reading",
142 git_path_merge_head(r));
143 }
144
145 while (!strbuf_getwholeline_fd(&line, merge_head, '\n')) {
146 struct object_id oid;
147 if (line.len < GIT_SHA1_HEXSZ || get_oid_hex(line.buf, &oid))
148 die("unknown line in '%s': %s",
149 git_path_merge_head(r), line.buf);
150 tail = append_parent(r, tail, &oid);
151 }
152 close(merge_head);
153 strbuf_release(&line);
154 }
155
156 /*
157 * This isn't as simple as passing sb->buf and sb->len, because we
158 * want to transfer ownership of the buffer to the commit (so we
159 * must use detach).
160 */
161 static void set_commit_buffer_from_strbuf(struct repository *r,
162 struct commit *c,
163 struct strbuf *sb)
164 {
165 size_t len;
166 void *buf = strbuf_detach(sb, &len);
167 set_commit_buffer(r, c, buf, len);
168 }
169
170 /*
171 * Prepare a dummy commit that represents the work tree (or staged) item.
172 * Note that annotating work tree item never works in the reverse.
173 */
174 static struct commit *fake_working_tree_commit(struct repository *r,
175 struct diff_options *opt,
176 const char *path,
177 const char *contents_from)
178 {
179 struct commit *commit;
180 struct blame_origin *origin;
181 struct commit_list **parent_tail, *parent;
182 struct object_id head_oid;
183 struct strbuf buf = STRBUF_INIT;
184 const char *ident;
185 time_t now;
186 int len;
187 struct cache_entry *ce;
188 unsigned mode;
189 struct strbuf msg = STRBUF_INIT;
190
191 repo_read_index(r);
192 time(&now);
193 commit = alloc_commit_node(r);
194 commit->object.parsed = 1;
195 commit->date = now;
196 parent_tail = &commit->parents;
197
198 if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
199 die("no such ref: HEAD");
200
201 parent_tail = append_parent(r, parent_tail, &head_oid);
202 append_merge_parents(r, parent_tail);
203 verify_working_tree_path(r, commit, path);
204
205 origin = make_origin(commit, path);
206
207 ident = fmt_ident("Not Committed Yet", "not.committed.yet",
208 WANT_BLANK_IDENT, NULL, 0);
209 strbuf_addstr(&msg, "tree 0000000000000000000000000000000000000000\n");
210 for (parent = commit->parents; parent; parent = parent->next)
211 strbuf_addf(&msg, "parent %s\n",
212 oid_to_hex(&parent->item->object.oid));
213 strbuf_addf(&msg,
214 "author %s\n"
215 "committer %s\n\n"
216 "Version of %s from %s\n",
217 ident, ident, path,
218 (!contents_from ? path :
219 (!strcmp(contents_from, "-") ? "standard input" : contents_from)));
220 set_commit_buffer_from_strbuf(r, commit, &msg);
221
222 if (!contents_from || strcmp("-", contents_from)) {
223 struct stat st;
224 const char *read_from;
225 char *buf_ptr;
226 unsigned long buf_len;
227
228 if (contents_from) {
229 if (stat(contents_from, &st) < 0)
230 die_errno("Cannot stat '%s'", contents_from);
231 read_from = contents_from;
232 }
233 else {
234 if (lstat(path, &st) < 0)
235 die_errno("Cannot lstat '%s'", path);
236 read_from = path;
237 }
238 mode = canon_mode(st.st_mode);
239
240 switch (st.st_mode & S_IFMT) {
241 case S_IFREG:
242 if (opt->flags.allow_textconv &&
243 textconv_object(r, read_from, mode, &null_oid, 0, &buf_ptr, &buf_len))
244 strbuf_attach(&buf, buf_ptr, buf_len, buf_len + 1);
245 else if (strbuf_read_file(&buf, read_from, st.st_size) != st.st_size)
246 die_errno("cannot open or read '%s'", read_from);
247 break;
248 case S_IFLNK:
249 if (strbuf_readlink(&buf, read_from, st.st_size) < 0)
250 die_errno("cannot readlink '%s'", read_from);
251 break;
252 default:
253 die("unsupported file type %s", read_from);
254 }
255 }
256 else {
257 /* Reading from stdin */
258 mode = 0;
259 if (strbuf_read(&buf, 0, 0) < 0)
260 die_errno("failed to read from stdin");
261 }
262 convert_to_git(r->index, path, buf.buf, buf.len, &buf, 0);
263 origin->file.ptr = buf.buf;
264 origin->file.size = buf.len;
265 pretend_object_file(buf.buf, buf.len, OBJ_BLOB, &origin->blob_oid);
266
267 /*
268 * Read the current index, replace the path entry with
269 * origin->blob_sha1 without mucking with its mode or type
270 * bits; we are not going to write this index out -- we just
271 * want to run "diff-index --cached".
272 */
273 discard_index(r->index);
274 repo_read_index(r);
275
276 len = strlen(path);
277 if (!mode) {
278 int pos = index_name_pos(r->index, path, len);
279 if (0 <= pos)
280 mode = r->index->cache[pos]->ce_mode;
281 else
282 /* Let's not bother reading from HEAD tree */
283 mode = S_IFREG | 0644;
284 }
285 ce = make_empty_cache_entry(r->index, len);
286 oidcpy(&ce->oid, &origin->blob_oid);
287 memcpy(ce->name, path, len);
288 ce->ce_flags = create_ce_flags(0);
289 ce->ce_namelen = len;
290 ce->ce_mode = create_ce_mode(mode);
291 add_index_entry(r->index, ce,
292 ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
293
294 cache_tree_invalidate_path(r->index, path);
295
296 return commit;
297 }
298
299
300
301 static int diff_hunks(mmfile_t *file_a, mmfile_t *file_b,
302 xdl_emit_hunk_consume_func_t hunk_func, void *cb_data, int xdl_opts)
303 {
304 xpparam_t xpp = {0};
305 xdemitconf_t xecfg = {0};
306 xdemitcb_t ecb = {NULL};
307
308 xpp.flags = xdl_opts;
309 xecfg.hunk_func = hunk_func;
310 ecb.priv = cb_data;
311 return xdi_diff(file_a, file_b, &xpp, &xecfg, &ecb);
312 }
313
314 static const char *get_next_line(const char *start, const char *end)
315 {
316 const char *nl = memchr(start, '\n', end - start);
317
318 return nl ? nl + 1 : end;
319 }
320
321 static int find_line_starts(int **line_starts, const char *buf,
322 unsigned long len)
323 {
324 const char *end = buf + len;
325 const char *p;
326 int *lineno;
327 int num = 0;
328
329 for (p = buf; p < end; p = get_next_line(p, end))
330 num++;
331
332 ALLOC_ARRAY(*line_starts, num + 1);
333 lineno = *line_starts;
334
335 for (p = buf; p < end; p = get_next_line(p, end))
336 *lineno++ = p - buf;
337
338 *lineno = len;
339
340 return num;
341 }
342
343 struct fingerprint_entry;
344
345 /* A fingerprint is intended to loosely represent a string, such that two
346 * fingerprints can be quickly compared to give an indication of the similarity
347 * of the strings that they represent.
348 *
349 * A fingerprint is represented as a multiset of the lower-cased byte pairs in
350 * the string that it represents. Whitespace is added at each end of the
351 * string. Whitespace pairs are ignored. Whitespace is converted to '\0'.
352 * For example, the string "Darth Radar" will be converted to the following
353 * fingerprint:
354 * {"\0d", "da", "da", "ar", "ar", "rt", "th", "h\0", "\0r", "ra", "ad", "r\0"}
355 *
356 * The similarity between two fingerprints is the size of the intersection of
357 * their multisets, including repeated elements. See fingerprint_similarity for
358 * examples.
359 *
360 * For ease of implementation, the fingerprint is implemented as a map
361 * of byte pairs to the count of that byte pair in the string, instead of
362 * allowing repeated elements in a set.
363 */
364 struct fingerprint {
365 struct hashmap map;
366 /* As we know the maximum number of entries in advance, it's
367 * convenient to store the entries in a single array instead of having
368 * the hashmap manage the memory.
369 */
370 struct fingerprint_entry *entries;
371 };
372
373 /* A byte pair in a fingerprint. Stores the number of times the byte pair
374 * occurs in the string that the fingerprint represents.
375 */
376 struct fingerprint_entry {
377 /* The hashmap entry - the hash represents the byte pair in its
378 * entirety so we don't need to store the byte pair separately.
379 */
380 struct hashmap_entry entry;
381 /* The number of times the byte pair occurs in the string that the
382 * fingerprint represents.
383 */
384 int count;
385 };
386
387 /* See `struct fingerprint` for an explanation of what a fingerprint is.
388 * \param result the fingerprint of the string is stored here. This must be
389 * freed later using free_fingerprint.
390 * \param line_begin the start of the string
391 * \param line_end the end of the string
392 */
393 static void get_fingerprint(struct fingerprint *result,
394 const char *line_begin,
395 const char *line_end)
396 {
397 unsigned int hash, c0 = 0, c1;
398 const char *p;
399 int max_map_entry_count = 1 + line_end - line_begin;
400 struct fingerprint_entry *entry = xcalloc(max_map_entry_count,
401 sizeof(struct fingerprint_entry));
402 struct fingerprint_entry *found_entry;
403
404 hashmap_init(&result->map, NULL, NULL, max_map_entry_count);
405 result->entries = entry;
406 for (p = line_begin; p <= line_end; ++p, c0 = c1) {
407 /* Always terminate the string with whitespace.
408 * Normalise whitespace to 0, and normalise letters to
409 * lower case. This won't work for multibyte characters but at
410 * worst will match some unrelated characters.
411 */
412 if ((p == line_end) || isspace(*p))
413 c1 = 0;
414 else
415 c1 = tolower(*p);
416 hash = c0 | (c1 << 8);
417 /* Ignore whitespace pairs */
418 if (hash == 0)
419 continue;
420 hashmap_entry_init(entry, hash);
421
422 found_entry = hashmap_get(&result->map, entry, NULL);
423 if (found_entry) {
424 found_entry->count += 1;
425 } else {
426 entry->count = 1;
427 hashmap_add(&result->map, entry);
428 ++entry;
429 }
430 }
431 }
432
433 static void free_fingerprint(struct fingerprint *f)
434 {
435 hashmap_free(&f->map, 0);
436 free(f->entries);
437 }
438
439 /* Calculates the similarity between two fingerprints as the size of the
440 * intersection of their multisets, including repeated elements. See
441 * `struct fingerprint` for an explanation of the fingerprint representation.
442 * The similarity between "cat mat" and "father rather" is 2 because "at" is
443 * present twice in both strings while the similarity between "tim" and "mit"
444 * is 0.
445 */
446 static int fingerprint_similarity(struct fingerprint *a, struct fingerprint *b)
447 {
448 int intersection = 0;
449 struct hashmap_iter iter;
450 const struct fingerprint_entry *entry_a, *entry_b;
451
452 hashmap_iter_init(&b->map, &iter);
453
454 while ((entry_b = hashmap_iter_next(&iter))) {
455 if ((entry_a = hashmap_get(&a->map, entry_b, NULL))) {
456 intersection += entry_a->count < entry_b->count ?
457 entry_a->count : entry_b->count;
458 }
459 }
460 return intersection;
461 }
462
463 /* Subtracts byte-pair elements in B from A, modifying A in place.
464 */
465 static void fingerprint_subtract(struct fingerprint *a, struct fingerprint *b)
466 {
467 struct hashmap_iter iter;
468 struct fingerprint_entry *entry_a;
469 const struct fingerprint_entry *entry_b;
470
471 hashmap_iter_init(&b->map, &iter);
472
473 while ((entry_b = hashmap_iter_next(&iter))) {
474 if ((entry_a = hashmap_get(&a->map, entry_b, NULL))) {
475 if (entry_a->count <= entry_b->count)
476 hashmap_remove(&a->map, entry_b, NULL);
477 else
478 entry_a->count -= entry_b->count;
479 }
480 }
481 }
482
483 /* Calculate fingerprints for a series of lines.
484 * Puts the fingerprints in the fingerprints array, which must have been
485 * preallocated to allow storing line_count elements.
486 */
487 static void get_line_fingerprints(struct fingerprint *fingerprints,
488 const char *content, const int *line_starts,
489 long first_line, long line_count)
490 {
491 int i;
492 const char *linestart, *lineend;
493
494 line_starts += first_line;
495 for (i = 0; i < line_count; ++i) {
496 linestart = content + line_starts[i];
497 lineend = content + line_starts[i + 1];
498 get_fingerprint(fingerprints + i, linestart, lineend);
499 }
500 }
501
502 static void free_line_fingerprints(struct fingerprint *fingerprints,
503 int nr_fingerprints)
504 {
505 int i;
506
507 for (i = 0; i < nr_fingerprints; i++)
508 free_fingerprint(&fingerprints[i]);
509 }
510
511 /* This contains the data necessary to linearly map a line number in one half
512 * of a diff chunk to the line in the other half of the diff chunk that is
513 * closest in terms of its position as a fraction of the length of the chunk.
514 */
515 struct line_number_mapping {
516 int destination_start, destination_length,
517 source_start, source_length;
518 };
519
520 /* Given a line number in one range, offset and scale it to map it onto the
521 * other range.
522 * Essentially this mapping is a simple linear equation but the calculation is
523 * more complicated to allow performing it with integer operations.
524 * Another complication is that if a line could map onto many lines in the
525 * destination range then we want to choose the line at the center of those
526 * possibilities.
527 * Example: if the chunk is 2 lines long in A and 10 lines long in B then the
528 * first 5 lines in B will map onto the first line in the A chunk, while the
529 * last 5 lines will all map onto the second line in the A chunk.
530 * Example: if the chunk is 10 lines long in A and 2 lines long in B then line
531 * 0 in B will map onto line 2 in A, and line 1 in B will map onto line 7 in A.
532 */
533 static int map_line_number(int line_number,
534 const struct line_number_mapping *mapping)
535 {
536 return ((line_number - mapping->source_start) * 2 + 1) *
537 mapping->destination_length /
538 (mapping->source_length * 2) +
539 mapping->destination_start;
540 }
541
542 /* Get a pointer to the element storing the similarity between a line in A
543 * and a line in B.
544 *
545 * The similarities are stored in a 2-dimensional array. Each "row" in the
546 * array contains the similarities for a line in B. The similarities stored in
547 * a row are the similarities between the line in B and the nearby lines in A.
548 * To keep the length of each row the same, it is padded out with values of -1
549 * where the search range extends beyond the lines in A.
550 * For example, if max_search_distance_a is 2 and the two sides of a diff chunk
551 * look like this:
552 * a | m
553 * b | n
554 * c | o
555 * d | p
556 * e | q
557 * Then the similarity array will contain:
558 * [-1, -1, am, bm, cm,
559 * -1, an, bn, cn, dn,
560 * ao, bo, co, do, eo,
561 * bp, cp, dp, ep, -1,
562 * cq, dq, eq, -1, -1]
563 * Where similarities are denoted either by -1 for invalid, or the
564 * concatenation of the two lines in the diff being compared.
565 *
566 * \param similarities array of similarities between lines in A and B
567 * \param line_a the index of the line in A, in the same frame of reference as
568 * closest_line_a.
569 * \param local_line_b the index of the line in B, relative to the first line
570 * in B that similarities represents.
571 * \param closest_line_a the index of the line in A that is deemed to be
572 * closest to local_line_b. This must be in the same
573 * frame of reference as line_a. This value defines
574 * where similarities is centered for the line in B.
575 * \param max_search_distance_a maximum distance in lines from the closest line
576 * in A for other lines in A for which
577 * similarities may be calculated.
578 */
579 static int *get_similarity(int *similarities,
580 int line_a, int local_line_b,
581 int closest_line_a, int max_search_distance_a)
582 {
583 assert(abs(line_a - closest_line_a) <=
584 max_search_distance_a);
585 return similarities + line_a - closest_line_a +
586 max_search_distance_a +
587 local_line_b * (max_search_distance_a * 2 + 1);
588 }
589
590 #define CERTAIN_NOTHING_MATCHES -2
591 #define CERTAINTY_NOT_CALCULATED -1
592
593 /* Given a line in B, first calculate its similarities with nearby lines in A
594 * if not already calculated, then identify the most similar and second most
595 * similar lines. The "certainty" is calculated based on those two
596 * similarities.
597 *
598 * \param start_a the index of the first line of the chunk in A
599 * \param length_a the length in lines of the chunk in A
600 * \param local_line_b the index of the line in B, relative to the first line
601 * in the chunk.
602 * \param fingerprints_a array of fingerprints for the chunk in A
603 * \param fingerprints_b array of fingerprints for the chunk in B
604 * \param similarities 2-dimensional array of similarities between lines in A
605 * and B. See get_similarity() for more details.
606 * \param certainties array of values indicating how strongly a line in B is
607 * matched with some line in A.
608 * \param second_best_result array of absolute indices in A for the second
609 * closest match of a line in B.
610 * \param result array of absolute indices in A for the closest match of a line
611 * in B.
612 * \param max_search_distance_a maximum distance in lines from the closest line
613 * in A for other lines in A for which
614 * similarities may be calculated.
615 * \param map_line_number_in_b_to_a parameter to map_line_number().
616 */
617 static void find_best_line_matches(
618 int start_a,
619 int length_a,
620 int start_b,
621 int local_line_b,
622 struct fingerprint *fingerprints_a,
623 struct fingerprint *fingerprints_b,
624 int *similarities,
625 int *certainties,
626 int *second_best_result,
627 int *result,
628 const int max_search_distance_a,
629 const struct line_number_mapping *map_line_number_in_b_to_a)
630 {
631
632 int i, search_start, search_end, closest_local_line_a, *similarity,
633 best_similarity = 0, second_best_similarity = 0,
634 best_similarity_index = 0, second_best_similarity_index = 0;
635
636 /* certainty has already been calculated so no need to redo the work */
637 if (certainties[local_line_b] != CERTAINTY_NOT_CALCULATED)
638 return;
639
640 closest_local_line_a = map_line_number(
641 local_line_b + start_b, map_line_number_in_b_to_a) - start_a;
642
643 search_start = closest_local_line_a - max_search_distance_a;
644 if (search_start < 0)
645 search_start = 0;
646
647 search_end = closest_local_line_a + max_search_distance_a + 1;
648 if (search_end > length_a)
649 search_end = length_a;
650
651 for (i = search_start; i < search_end; ++i) {
652 similarity = get_similarity(similarities,
653 i, local_line_b,
654 closest_local_line_a,
655 max_search_distance_a);
656 if (*similarity == -1) {
657 /* This value will never exceed 10 but assert just in
658 * case
659 */
660 assert(abs(i - closest_local_line_a) < 1000);
661 /* scale the similarity by (1000 - distance from
662 * closest line) to act as a tie break between lines
663 * that otherwise are equally similar.
664 */
665 *similarity = fingerprint_similarity(
666 fingerprints_b + local_line_b,
667 fingerprints_a + i) *
668 (1000 - abs(i - closest_local_line_a));
669 }
670 if (*similarity > best_similarity) {
671 second_best_similarity = best_similarity;
672 second_best_similarity_index = best_similarity_index;
673 best_similarity = *similarity;
674 best_similarity_index = i;
675 } else if (*similarity > second_best_similarity) {
676 second_best_similarity = *similarity;
677 second_best_similarity_index = i;
678 }
679 }
680
681 if (best_similarity == 0) {
682 /* this line definitely doesn't match with anything. Mark it
683 * with this special value so it doesn't get invalidated and
684 * won't be recalculated.
685 */
686 certainties[local_line_b] = CERTAIN_NOTHING_MATCHES;
687 result[local_line_b] = -1;
688 } else {
689 /* Calculate the certainty with which this line matches.
690 * If the line matches well with two lines then that reduces
691 * the certainty. However we still want to prioritise matching
692 * a line that matches very well with two lines over matching a
693 * line that matches poorly with one line, hence doubling
694 * best_similarity.
695 * This means that if we have
696 * line X that matches only one line with a score of 3,
697 * line Y that matches two lines equally with a score of 5,
698 * and line Z that matches only one line with a score or 2,
699 * then the lines in order of certainty are X, Y, Z.
700 */
701 certainties[local_line_b] = best_similarity * 2 -
702 second_best_similarity;
703
704 /* We keep both the best and second best results to allow us to
705 * check at a later stage of the matching process whether the
706 * result needs to be invalidated.
707 */
708 result[local_line_b] = start_a + best_similarity_index;
709 second_best_result[local_line_b] =
710 start_a + second_best_similarity_index;
711 }
712 }
713
714 /*
715 * This finds the line that we can match with the most confidence, and
716 * uses it as a partition. It then calls itself on the lines on either side of
717 * that partition. In this way we avoid lines appearing out of order, and
718 * retain a sensible line ordering.
719 * \param start_a index of the first line in A with which lines in B may be
720 * compared.
721 * \param start_b index of the first line in B for which matching should be
722 * done.
723 * \param length_a number of lines in A with which lines in B may be compared.
724 * \param length_b number of lines in B for which matching should be done.
725 * \param fingerprints_a mutable array of fingerprints in A. The first element
726 * corresponds to the line at start_a.
727 * \param fingerprints_b array of fingerprints in B. The first element
728 * corresponds to the line at start_b.
729 * \param similarities 2-dimensional array of similarities between lines in A
730 * and B. See get_similarity() for more details.
731 * \param certainties array of values indicating how strongly a line in B is
732 * matched with some line in A.
733 * \param second_best_result array of absolute indices in A for the second
734 * closest match of a line in B.
735 * \param result array of absolute indices in A for the closest match of a line
736 * in B.
737 * \param max_search_distance_a maximum distance in lines from the closest line
738 * in A for other lines in A for which
739 * similarities may be calculated.
740 * \param max_search_distance_b an upper bound on the greatest possible
741 * distance between lines in B such that they will
742 * both be compared with the same line in A
743 * according to max_search_distance_a.
744 * \param map_line_number_in_b_to_a parameter to map_line_number().
745 */
746 static void fuzzy_find_matching_lines_recurse(
747 int start_a, int start_b,
748 int length_a, int length_b,
749 struct fingerprint *fingerprints_a,
750 struct fingerprint *fingerprints_b,
751 int *similarities,
752 int *certainties,
753 int *second_best_result,
754 int *result,
755 int max_search_distance_a,
756 int max_search_distance_b,
757 const struct line_number_mapping *map_line_number_in_b_to_a)
758 {
759 int i, invalidate_min, invalidate_max, offset_b,
760 second_half_start_a, second_half_start_b,
761 second_half_length_a, second_half_length_b,
762 most_certain_line_a, most_certain_local_line_b = -1,
763 most_certain_line_certainty = -1,
764 closest_local_line_a;
765
766 for (i = 0; i < length_b; ++i) {
767 find_best_line_matches(start_a,
768 length_a,
769 start_b,
770 i,
771 fingerprints_a,
772 fingerprints_b,
773 similarities,
774 certainties,
775 second_best_result,
776 result,
777 max_search_distance_a,
778 map_line_number_in_b_to_a);
779
780 if (certainties[i] > most_certain_line_certainty) {
781 most_certain_line_certainty = certainties[i];
782 most_certain_local_line_b = i;
783 }
784 }
785
786 /* No matches. */
787 if (most_certain_local_line_b == -1)
788 return;
789
790 most_certain_line_a = result[most_certain_local_line_b];
791
792 /*
793 * Subtract the most certain line's fingerprint in B from the matched
794 * fingerprint in A. This means that other lines in B can't also match
795 * the same parts of the line in A.
796 */
797 fingerprint_subtract(fingerprints_a + most_certain_line_a - start_a,
798 fingerprints_b + most_certain_local_line_b);
799
800 /* Invalidate results that may be affected by the choice of most
801 * certain line.
802 */
803 invalidate_min = most_certain_local_line_b - max_search_distance_b;
804 invalidate_max = most_certain_local_line_b + max_search_distance_b + 1;
805 if (invalidate_min < 0)
806 invalidate_min = 0;
807 if (invalidate_max > length_b)
808 invalidate_max = length_b;
809
810 /* As the fingerprint in A has changed, discard previously calculated
811 * similarity values with that fingerprint.
812 */
813 for (i = invalidate_min; i < invalidate_max; ++i) {
814 closest_local_line_a = map_line_number(
815 i + start_b, map_line_number_in_b_to_a) - start_a;
816
817 /* Check that the lines in A and B are close enough that there
818 * is a similarity value for them.
819 */
820 if (abs(most_certain_line_a - start_a - closest_local_line_a) >
821 max_search_distance_a) {
822 continue;
823 }
824
825 *get_similarity(similarities, most_certain_line_a - start_a,
826 i, closest_local_line_a,
827 max_search_distance_a) = -1;
828 }
829
830 /* More invalidating of results that may be affected by the choice of
831 * most certain line.
832 * Discard the matches for lines in B that are currently matched with a
833 * line in A such that their ordering contradicts the ordering imposed
834 * by the choice of most certain line.
835 */
836 for (i = most_certain_local_line_b - 1; i >= invalidate_min; --i) {
837 /* In this loop we discard results for lines in B that are
838 * before most-certain-line-B but are matched with a line in A
839 * that is after most-certain-line-A.
840 */
841 if (certainties[i] >= 0 &&
842 (result[i] >= most_certain_line_a ||
843 second_best_result[i] >= most_certain_line_a)) {
844 certainties[i] = CERTAINTY_NOT_CALCULATED;
845 }
846 }
847 for (i = most_certain_local_line_b + 1; i < invalidate_max; ++i) {
848 /* In this loop we discard results for lines in B that are
849 * after most-certain-line-B but are matched with a line in A
850 * that is before most-certain-line-A.
851 */
852 if (certainties[i] >= 0 &&
853 (result[i] <= most_certain_line_a ||
854 second_best_result[i] <= most_certain_line_a)) {
855 certainties[i] = CERTAINTY_NOT_CALCULATED;
856 }
857 }
858
859 /* Repeat the matching process for lines before the most certain line.
860 */
861 if (most_certain_local_line_b > 0) {
862 fuzzy_find_matching_lines_recurse(
863 start_a, start_b,
864 most_certain_line_a + 1 - start_a,
865 most_certain_local_line_b,
866 fingerprints_a, fingerprints_b, similarities,
867 certainties, second_best_result, result,
868 max_search_distance_a,
869 max_search_distance_b,
870 map_line_number_in_b_to_a);
871 }
872 /* Repeat the matching process for lines after the most certain line.
873 */
874 if (most_certain_local_line_b + 1 < length_b) {
875 second_half_start_a = most_certain_line_a;
876 offset_b = most_certain_local_line_b + 1;
877 second_half_start_b = start_b + offset_b;
878 second_half_length_a =
879 length_a + start_a - second_half_start_a;
880 second_half_length_b =
881 length_b + start_b - second_half_start_b;
882 fuzzy_find_matching_lines_recurse(
883 second_half_start_a, second_half_start_b,
884 second_half_length_a, second_half_length_b,
885 fingerprints_a + second_half_start_a - start_a,
886 fingerprints_b + offset_b,
887 similarities +
888 offset_b * (max_search_distance_a * 2 + 1),
889 certainties + offset_b,
890 second_best_result + offset_b, result + offset_b,
891 max_search_distance_a,
892 max_search_distance_b,
893 map_line_number_in_b_to_a);
894 }
895 }
896
897 /* Find the lines in the parent line range that most closely match the lines in
898 * the target line range. This is accomplished by matching fingerprints in each
899 * blame_origin, and choosing the best matches that preserve the line ordering.
900 * See struct fingerprint for details of fingerprint matching, and
901 * fuzzy_find_matching_lines_recurse for details of preserving line ordering.
902 *
903 * The performance is believed to be O(n log n) in the typical case and O(n^2)
904 * in a pathological case, where n is the number of lines in the target range.
905 */
906 static int *fuzzy_find_matching_lines(struct blame_origin *parent,
907 struct blame_origin *target,
908 int tlno, int parent_slno, int same,
909 int parent_len)
910 {
911 /* We use the terminology "A" for the left hand side of the diff AKA
912 * parent, and "B" for the right hand side of the diff AKA target. */
913 int start_a = parent_slno;
914 int length_a = parent_len;
915 int start_b = tlno;
916 int length_b = same - tlno;
917
918 struct line_number_mapping map_line_number_in_b_to_a = {
919 start_a, length_a, start_b, length_b
920 };
921
922 struct fingerprint *fingerprints_a = parent->fingerprints;
923 struct fingerprint *fingerprints_b = target->fingerprints;
924
925 int i, *result, *second_best_result,
926 *certainties, *similarities, similarity_count;
927
928 /*
929 * max_search_distance_a means that given a line in B, compare it to
930 * the line in A that is closest to its position, and the lines in A
931 * that are no greater than max_search_distance_a lines away from the
932 * closest line in A.
933 *
934 * max_search_distance_b is an upper bound on the greatest possible
935 * distance between lines in B such that they will both be compared
936 * with the same line in A according to max_search_distance_a.
937 */
938 int max_search_distance_a = 10, max_search_distance_b;
939
940 if (length_a <= 0)
941 return NULL;
942
943 if (max_search_distance_a >= length_a)
944 max_search_distance_a = length_a ? length_a - 1 : 0;
945
946 max_search_distance_b = ((2 * max_search_distance_a + 1) * length_b
947 - 1) / length_a;
948
949 result = xcalloc(sizeof(int), length_b);
950 second_best_result = xcalloc(sizeof(int), length_b);
951 certainties = xcalloc(sizeof(int), length_b);
952
953 /* See get_similarity() for details of similarities. */
954 similarity_count = length_b * (max_search_distance_a * 2 + 1);
955 similarities = xcalloc(sizeof(int), similarity_count);
956
957 for (i = 0; i < length_b; ++i) {
958 result[i] = -1;
959 second_best_result[i] = -1;
960 certainties[i] = CERTAINTY_NOT_CALCULATED;
961 }
962
963 for (i = 0; i < similarity_count; ++i)
964 similarities[i] = -1;
965
966 fuzzy_find_matching_lines_recurse(start_a, start_b,
967 length_a, length_b,
968 fingerprints_a + start_a,
969 fingerprints_b + start_b,
970 similarities,
971 certainties,
972 second_best_result,
973 result,
974 max_search_distance_a,
975 max_search_distance_b,
976 &map_line_number_in_b_to_a);
977
978 free(similarities);
979 free(certainties);
980 free(second_best_result);
981
982 return result;
983 }
984
985 static void fill_origin_fingerprints(struct blame_origin *o)
986 {
987 int *line_starts;
988
989 if (o->fingerprints)
990 return;
991 o->num_lines = find_line_starts(&line_starts, o->file.ptr,
992 o->file.size);
993 o->fingerprints = xcalloc(sizeof(struct fingerprint), o->num_lines);
994 get_line_fingerprints(o->fingerprints, o->file.ptr, line_starts,
995 0, o->num_lines);
996 free(line_starts);
997 }
998
999 static void drop_origin_fingerprints(struct blame_origin *o)
1000 {
1001 if (o->fingerprints) {
1002 free_line_fingerprints(o->fingerprints, o->num_lines);
1003 o->num_lines = 0;
1004 FREE_AND_NULL(o->fingerprints);
1005 }
1006 }
1007
1008 /*
1009 * Given an origin, prepare mmfile_t structure to be used by the
1010 * diff machinery
1011 */
1012 static void fill_origin_blob(struct diff_options *opt,
1013 struct blame_origin *o, mmfile_t *file,
1014 int *num_read_blob, int fill_fingerprints)
1015 {
1016 if (!o->file.ptr) {
1017 enum object_type type;
1018 unsigned long file_size;
1019
1020 (*num_read_blob)++;
1021 if (opt->flags.allow_textconv &&
1022 textconv_object(opt->repo, o->path, o->mode,
1023 &o->blob_oid, 1, &file->ptr, &file_size))
1024 ;
1025 else
1026 file->ptr = read_object_file(&o->blob_oid, &type,
1027 &file_size);
1028 file->size = file_size;
1029
1030 if (!file->ptr)
1031 die("Cannot read blob %s for path %s",
1032 oid_to_hex(&o->blob_oid),
1033 o->path);
1034 o->file = *file;
1035 }
1036 else
1037 *file = o->file;
1038 if (fill_fingerprints)
1039 fill_origin_fingerprints(o);
1040 }
1041
1042 static void drop_origin_blob(struct blame_origin *o)
1043 {
1044 FREE_AND_NULL(o->file.ptr);
1045 drop_origin_fingerprints(o);
1046 }
1047
1048 /*
1049 * Any merge of blames happens on lists of blames that arrived via
1050 * different parents in a single suspect. In this case, we want to
1051 * sort according to the suspect line numbers as opposed to the final
1052 * image line numbers. The function body is somewhat longish because
1053 * it avoids unnecessary writes.
1054 */
1055
1056 static struct blame_entry *blame_merge(struct blame_entry *list1,
1057 struct blame_entry *list2)
1058 {
1059 struct blame_entry *p1 = list1, *p2 = list2,
1060 **tail = &list1;
1061
1062 if (!p1)
1063 return p2;
1064 if (!p2)
1065 return p1;
1066
1067 if (p1->s_lno <= p2->s_lno) {
1068 do {
1069 tail = &p1->next;
1070 if ((p1 = *tail) == NULL) {
1071 *tail = p2;
1072 return list1;
1073 }
1074 } while (p1->s_lno <= p2->s_lno);
1075 }
1076 for (;;) {
1077 *tail = p2;
1078 do {
1079 tail = &p2->next;
1080 if ((p2 = *tail) == NULL) {
1081 *tail = p1;
1082 return list1;
1083 }
1084 } while (p1->s_lno > p2->s_lno);
1085 *tail = p1;
1086 do {
1087 tail = &p1->next;
1088 if ((p1 = *tail) == NULL) {
1089 *tail = p2;
1090 return list1;
1091 }
1092 } while (p1->s_lno <= p2->s_lno);
1093 }
1094 }
1095
1096 static void *get_next_blame(const void *p)
1097 {
1098 return ((struct blame_entry *)p)->next;
1099 }
1100
1101 static void set_next_blame(void *p1, void *p2)
1102 {
1103 ((struct blame_entry *)p1)->next = p2;
1104 }
1105
1106 /*
1107 * Final image line numbers are all different, so we don't need a
1108 * three-way comparison here.
1109 */
1110
1111 static int compare_blame_final(const void *p1, const void *p2)
1112 {
1113 return ((struct blame_entry *)p1)->lno > ((struct blame_entry *)p2)->lno
1114 ? 1 : -1;
1115 }
1116
1117 static int compare_blame_suspect(const void *p1, const void *p2)
1118 {
1119 const struct blame_entry *s1 = p1, *s2 = p2;
1120 /*
1121 * to allow for collating suspects, we sort according to the
1122 * respective pointer value as the primary sorting criterion.
1123 * The actual relation is pretty unimportant as long as it
1124 * establishes a total order. Comparing as integers gives us
1125 * that.
1126 */
1127 if (s1->suspect != s2->suspect)
1128 return (intptr_t)s1->suspect > (intptr_t)s2->suspect ? 1 : -1;
1129 if (s1->s_lno == s2->s_lno)
1130 return 0;
1131 return s1->s_lno > s2->s_lno ? 1 : -1;
1132 }
1133
1134 void blame_sort_final(struct blame_scoreboard *sb)
1135 {
1136 sb->ent = llist_mergesort(sb->ent, get_next_blame, set_next_blame,
1137 compare_blame_final);
1138 }
1139
1140 static int compare_commits_by_reverse_commit_date(const void *a,
1141 const void *b,
1142 void *c)
1143 {
1144 return -compare_commits_by_commit_date(a, b, c);
1145 }
1146
1147 /*
1148 * For debugging -- origin is refcounted, and this asserts that
1149 * we do not underflow.
1150 */
1151 static void sanity_check_refcnt(struct blame_scoreboard *sb)
1152 {
1153 int baa = 0;
1154 struct blame_entry *ent;
1155
1156 for (ent = sb->ent; ent; ent = ent->next) {
1157 /* Nobody should have zero or negative refcnt */
1158 if (ent->suspect->refcnt <= 0) {
1159 fprintf(stderr, "%s in %s has negative refcnt %d\n",
1160 ent->suspect->path,
1161 oid_to_hex(&ent->suspect->commit->object.oid),
1162 ent->suspect->refcnt);
1163 baa = 1;
1164 }
1165 }
1166 if (baa)
1167 sb->on_sanity_fail(sb, baa);
1168 }
1169
1170 /*
1171 * If two blame entries that are next to each other came from
1172 * contiguous lines in the same origin (i.e. <commit, path> pair),
1173 * merge them together.
1174 */
1175 void blame_coalesce(struct blame_scoreboard *sb)
1176 {
1177 struct blame_entry *ent, *next;
1178
1179 for (ent = sb->ent; ent && (next = ent->next); ent = next) {
1180 if (ent->suspect == next->suspect &&
1181 ent->s_lno + ent->num_lines == next->s_lno &&
1182 ent->ignored == next->ignored &&
1183 ent->unblamable == next->unblamable) {
1184 ent->num_lines += next->num_lines;
1185 ent->next = next->next;
1186 blame_origin_decref(next->suspect);
1187 free(next);
1188 ent->score = 0;
1189 next = ent; /* again */
1190 }
1191 }
1192
1193 if (sb->debug) /* sanity */
1194 sanity_check_refcnt(sb);
1195 }
1196
1197 /*
1198 * Merge the given sorted list of blames into a preexisting origin.
1199 * If there were no previous blames to that commit, it is entered into
1200 * the commit priority queue of the score board.
1201 */
1202
1203 static void queue_blames(struct blame_scoreboard *sb, struct blame_origin *porigin,
1204 struct blame_entry *sorted)
1205 {
1206 if (porigin->suspects)
1207 porigin->suspects = blame_merge(porigin->suspects, sorted);
1208 else {
1209 struct blame_origin *o;
1210 for (o = get_blame_suspects(porigin->commit); o; o = o->next) {
1211 if (o->suspects) {
1212 porigin->suspects = sorted;
1213 return;
1214 }
1215 }
1216 porigin->suspects = sorted;
1217 prio_queue_put(&sb->commits, porigin->commit);
1218 }
1219 }
1220
1221 /*
1222 * Fill the blob_sha1 field of an origin if it hasn't, so that later
1223 * call to fill_origin_blob() can use it to locate the data. blob_sha1
1224 * for an origin is also used to pass the blame for the entire file to
1225 * the parent to detect the case where a child's blob is identical to
1226 * that of its parent's.
1227 *
1228 * This also fills origin->mode for corresponding tree path.
1229 */
1230 static int fill_blob_sha1_and_mode(struct repository *r,
1231 struct blame_origin *origin)
1232 {
1233 if (!is_null_oid(&origin->blob_oid))
1234 return 0;
1235 if (get_tree_entry(r, &origin->commit->object.oid, origin->path, &origin->blob_oid, &origin->mode))
1236 goto error_out;
1237 if (oid_object_info(r, &origin->blob_oid, NULL) != OBJ_BLOB)
1238 goto error_out;
1239 return 0;
1240 error_out:
1241 oidclr(&origin->blob_oid);
1242 origin->mode = S_IFINVALID;
1243 return -1;
1244 }
1245
1246 /*
1247 * We have an origin -- check if the same path exists in the
1248 * parent and return an origin structure to represent it.
1249 */
1250 static struct blame_origin *find_origin(struct repository *r,
1251 struct commit *parent,
1252 struct blame_origin *origin)
1253 {
1254 struct blame_origin *porigin;
1255 struct diff_options diff_opts;
1256 const char *paths[2];
1257
1258 /* First check any existing origins */
1259 for (porigin = get_blame_suspects(parent); porigin; porigin = porigin->next)
1260 if (!strcmp(porigin->path, origin->path)) {
1261 /*
1262 * The same path between origin and its parent
1263 * without renaming -- the most common case.
1264 */
1265 return blame_origin_incref (porigin);
1266 }
1267
1268 /* See if the origin->path is different between parent
1269 * and origin first. Most of the time they are the
1270 * same and diff-tree is fairly efficient about this.
1271 */
1272 repo_diff_setup(r, &diff_opts);
1273 diff_opts.flags.recursive = 1;
1274 diff_opts.detect_rename = 0;
1275 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1276 paths[0] = origin->path;
1277 paths[1] = NULL;
1278
1279 parse_pathspec(&diff_opts.pathspec,
1280 PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
1281 PATHSPEC_LITERAL_PATH, "", paths);
1282 diff_setup_done(&diff_opts);
1283
1284 if (is_null_oid(&origin->commit->object.oid))
1285 do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
1286 else
1287 diff_tree_oid(get_commit_tree_oid(parent),
1288 get_commit_tree_oid(origin->commit),
1289 "", &diff_opts);
1290 diffcore_std(&diff_opts);
1291
1292 if (!diff_queued_diff.nr) {
1293 /* The path is the same as parent */
1294 porigin = get_origin(parent, origin->path);
1295 oidcpy(&porigin->blob_oid, &origin->blob_oid);
1296 porigin->mode = origin->mode;
1297 } else {
1298 /*
1299 * Since origin->path is a pathspec, if the parent
1300 * commit had it as a directory, we will see a whole
1301 * bunch of deletion of files in the directory that we
1302 * do not care about.
1303 */
1304 int i;
1305 struct diff_filepair *p = NULL;
1306 for (i = 0; i < diff_queued_diff.nr; i++) {
1307 const char *name;
1308 p = diff_queued_diff.queue[i];
1309 name = p->one->path ? p->one->path : p->two->path;
1310 if (!strcmp(name, origin->path))
1311 break;
1312 }
1313 if (!p)
1314 die("internal error in blame::find_origin");
1315 switch (p->status) {
1316 default:
1317 die("internal error in blame::find_origin (%c)",
1318 p->status);
1319 case 'M':
1320 porigin = get_origin(parent, origin->path);
1321 oidcpy(&porigin->blob_oid, &p->one->oid);
1322 porigin->mode = p->one->mode;
1323 break;
1324 case 'A':
1325 case 'T':
1326 /* Did not exist in parent, or type changed */
1327 break;
1328 }
1329 }
1330 diff_flush(&diff_opts);
1331 clear_pathspec(&diff_opts.pathspec);
1332 return porigin;
1333 }
1334
1335 /*
1336 * We have an origin -- find the path that corresponds to it in its
1337 * parent and return an origin structure to represent it.
1338 */
1339 static struct blame_origin *find_rename(struct repository *r,
1340 struct commit *parent,
1341 struct blame_origin *origin)
1342 {
1343 struct blame_origin *porigin = NULL;
1344 struct diff_options diff_opts;
1345 int i;
1346
1347 repo_diff_setup(r, &diff_opts);
1348 diff_opts.flags.recursive = 1;
1349 diff_opts.detect_rename = DIFF_DETECT_RENAME;
1350 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1351 diff_opts.single_follow = origin->path;
1352 diff_setup_done(&diff_opts);
1353
1354 if (is_null_oid(&origin->commit->object.oid))
1355 do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
1356 else
1357 diff_tree_oid(get_commit_tree_oid(parent),
1358 get_commit_tree_oid(origin->commit),
1359 "", &diff_opts);
1360 diffcore_std(&diff_opts);
1361
1362 for (i = 0; i < diff_queued_diff.nr; i++) {
1363 struct diff_filepair *p = diff_queued_diff.queue[i];
1364 if ((p->status == 'R' || p->status == 'C') &&
1365 !strcmp(p->two->path, origin->path)) {
1366 porigin = get_origin(parent, p->one->path);
1367 oidcpy(&porigin->blob_oid, &p->one->oid);
1368 porigin->mode = p->one->mode;
1369 break;
1370 }
1371 }
1372 diff_flush(&diff_opts);
1373 clear_pathspec(&diff_opts.pathspec);
1374 return porigin;
1375 }
1376
1377 /*
1378 * Append a new blame entry to a given output queue.
1379 */
1380 static void add_blame_entry(struct blame_entry ***queue,
1381 const struct blame_entry *src)
1382 {
1383 struct blame_entry *e = xmalloc(sizeof(*e));
1384 memcpy(e, src, sizeof(*e));
1385 blame_origin_incref(e->suspect);
1386
1387 e->next = **queue;
1388 **queue = e;
1389 *queue = &e->next;
1390 }
1391
1392 /*
1393 * src typically is on-stack; we want to copy the information in it to
1394 * a malloced blame_entry that gets added to the given queue. The
1395 * origin of dst loses a refcnt.
1396 */
1397 static void dup_entry(struct blame_entry ***queue,
1398 struct blame_entry *dst, struct blame_entry *src)
1399 {
1400 blame_origin_incref(src->suspect);
1401 blame_origin_decref(dst->suspect);
1402 memcpy(dst, src, sizeof(*src));
1403 dst->next = **queue;
1404 **queue = dst;
1405 *queue = &dst->next;
1406 }
1407
1408 const char *blame_nth_line(struct blame_scoreboard *sb, long lno)
1409 {
1410 return sb->final_buf + sb->lineno[lno];
1411 }
1412
1413 /*
1414 * It is known that lines between tlno to same came from parent, and e
1415 * has an overlap with that range. it also is known that parent's
1416 * line plno corresponds to e's line tlno.
1417 *
1418 * <---- e ----->
1419 * <------>
1420 * <------------>
1421 * <------------>
1422 * <------------------>
1423 *
1424 * Split e into potentially three parts; before this chunk, the chunk
1425 * to be blamed for the parent, and after that portion.
1426 */
1427 static void split_overlap(struct blame_entry *split,
1428 struct blame_entry *e,
1429 int tlno, int plno, int same,
1430 struct blame_origin *parent)
1431 {
1432 int chunk_end_lno;
1433 int i;
1434 memset(split, 0, sizeof(struct blame_entry [3]));
1435
1436 for (i = 0; i < 3; i++) {
1437 split[i].ignored = e->ignored;
1438 split[i].unblamable = e->unblamable;
1439 }
1440
1441 if (e->s_lno < tlno) {
1442 /* there is a pre-chunk part not blamed on parent */
1443 split[0].suspect = blame_origin_incref(e->suspect);
1444 split[0].lno = e->lno;
1445 split[0].s_lno = e->s_lno;
1446 split[0].num_lines = tlno - e->s_lno;
1447 split[1].lno = e->lno + tlno - e->s_lno;
1448 split[1].s_lno = plno;
1449 }
1450 else {
1451 split[1].lno = e->lno;
1452 split[1].s_lno = plno + (e->s_lno - tlno);
1453 }
1454
1455 if (same < e->s_lno + e->num_lines) {
1456 /* there is a post-chunk part not blamed on parent */
1457 split[2].suspect = blame_origin_incref(e->suspect);
1458 split[2].lno = e->lno + (same - e->s_lno);
1459 split[2].s_lno = e->s_lno + (same - e->s_lno);
1460 split[2].num_lines = e->s_lno + e->num_lines - same;
1461 chunk_end_lno = split[2].lno;
1462 }
1463 else
1464 chunk_end_lno = e->lno + e->num_lines;
1465 split[1].num_lines = chunk_end_lno - split[1].lno;
1466
1467 /*
1468 * if it turns out there is nothing to blame the parent for,
1469 * forget about the splitting. !split[1].suspect signals this.
1470 */
1471 if (split[1].num_lines < 1)
1472 return;
1473 split[1].suspect = blame_origin_incref(parent);
1474 }
1475
1476 /*
1477 * split_overlap() divided an existing blame e into up to three parts
1478 * in split. Any assigned blame is moved to queue to
1479 * reflect the split.
1480 */
1481 static void split_blame(struct blame_entry ***blamed,
1482 struct blame_entry ***unblamed,
1483 struct blame_entry *split,
1484 struct blame_entry *e)
1485 {
1486 if (split[0].suspect && split[2].suspect) {
1487 /* The first part (reuse storage for the existing entry e) */
1488 dup_entry(unblamed, e, &split[0]);
1489
1490 /* The last part -- me */
1491 add_blame_entry(unblamed, &split[2]);
1492
1493 /* ... and the middle part -- parent */
1494 add_blame_entry(blamed, &split[1]);
1495 }
1496 else if (!split[0].suspect && !split[2].suspect)
1497 /*
1498 * The parent covers the entire area; reuse storage for
1499 * e and replace it with the parent.
1500 */
1501 dup_entry(blamed, e, &split[1]);
1502 else if (split[0].suspect) {
1503 /* me and then parent */
1504 dup_entry(unblamed, e, &split[0]);
1505 add_blame_entry(blamed, &split[1]);
1506 }
1507 else {
1508 /* parent and then me */
1509 dup_entry(blamed, e, &split[1]);
1510 add_blame_entry(unblamed, &split[2]);
1511 }
1512 }
1513
1514 /*
1515 * After splitting the blame, the origins used by the
1516 * on-stack blame_entry should lose one refcnt each.
1517 */
1518 static void decref_split(struct blame_entry *split)
1519 {
1520 int i;
1521
1522 for (i = 0; i < 3; i++)
1523 blame_origin_decref(split[i].suspect);
1524 }
1525
1526 /*
1527 * reverse_blame reverses the list given in head, appending tail.
1528 * That allows us to build lists in reverse order, then reverse them
1529 * afterwards. This can be faster than building the list in proper
1530 * order right away. The reason is that building in proper order
1531 * requires writing a link in the _previous_ element, while building
1532 * in reverse order just requires placing the list head into the
1533 * _current_ element.
1534 */
1535
1536 static struct blame_entry *reverse_blame(struct blame_entry *head,
1537 struct blame_entry *tail)
1538 {
1539 while (head) {
1540 struct blame_entry *next = head->next;
1541 head->next = tail;
1542 tail = head;
1543 head = next;
1544 }
1545 return tail;
1546 }
1547
1548 /*
1549 * Splits a blame entry into two entries at 'len' lines. The original 'e'
1550 * consists of len lines, i.e. [e->lno, e->lno + len), and the second part,
1551 * which is returned, consists of the remainder: [e->lno + len, e->lno +
1552 * e->num_lines). The caller needs to sort out the reference counting for the
1553 * new entry's suspect.
1554 */
1555 static struct blame_entry *split_blame_at(struct blame_entry *e, int len,
1556 struct blame_origin *new_suspect)
1557 {
1558 struct blame_entry *n = xcalloc(1, sizeof(struct blame_entry));
1559
1560 n->suspect = new_suspect;
1561 n->ignored = e->ignored;
1562 n->unblamable = e->unblamable;
1563 n->lno = e->lno + len;
1564 n->s_lno = e->s_lno + len;
1565 n->num_lines = e->num_lines - len;
1566 e->num_lines = len;
1567 e->score = 0;
1568 return n;
1569 }
1570
1571 struct blame_line_tracker {
1572 int is_parent;
1573 int s_lno;
1574 };
1575
1576 static int are_lines_adjacent(struct blame_line_tracker *first,
1577 struct blame_line_tracker *second)
1578 {
1579 return first->is_parent == second->is_parent &&
1580 first->s_lno + 1 == second->s_lno;
1581 }
1582
1583 static int scan_parent_range(struct fingerprint *p_fps,
1584 struct fingerprint *t_fps, int t_idx,
1585 int from, int nr_lines)
1586 {
1587 int sim, p_idx;
1588 #define FINGERPRINT_FILE_THRESHOLD 10
1589 int best_sim_val = FINGERPRINT_FILE_THRESHOLD;
1590 int best_sim_idx = -1;
1591
1592 for (p_idx = from; p_idx < from + nr_lines; p_idx++) {
1593 sim = fingerprint_similarity(&t_fps[t_idx], &p_fps[p_idx]);
1594 if (sim < best_sim_val)
1595 continue;
1596 /* Break ties with the closest-to-target line number */
1597 if (sim == best_sim_val && best_sim_idx != -1 &&
1598 abs(best_sim_idx - t_idx) < abs(p_idx - t_idx))
1599 continue;
1600 best_sim_val = sim;
1601 best_sim_idx = p_idx;
1602 }
1603 return best_sim_idx;
1604 }
1605
1606 /*
1607 * The first pass checks the blame entry (from the target) against the parent's
1608 * diff chunk. If that fails for a line, the second pass tries to match that
1609 * line to any part of parent file. That catches cases where a change was
1610 * broken into two chunks by 'context.'
1611 */
1612 static void guess_line_blames(struct blame_origin *parent,
1613 struct blame_origin *target,
1614 int tlno, int offset, int same, int parent_len,
1615 struct blame_line_tracker *line_blames)
1616 {
1617 int i, best_idx, target_idx;
1618 int parent_slno = tlno + offset;
1619 int *fuzzy_matches;
1620
1621 fuzzy_matches = fuzzy_find_matching_lines(parent, target,
1622 tlno, parent_slno, same,
1623 parent_len);
1624 for (i = 0; i < same - tlno; i++) {
1625 target_idx = tlno + i;
1626 if (fuzzy_matches && fuzzy_matches[i] >= 0) {
1627 best_idx = fuzzy_matches[i];
1628 } else {
1629 best_idx = scan_parent_range(parent->fingerprints,
1630 target->fingerprints,
1631 target_idx, 0,
1632 parent->num_lines);
1633 }
1634 if (best_idx >= 0) {
1635 line_blames[i].is_parent = 1;
1636 line_blames[i].s_lno = best_idx;
1637 } else {
1638 line_blames[i].is_parent = 0;
1639 line_blames[i].s_lno = target_idx;
1640 }
1641 }
1642 free(fuzzy_matches);
1643 }
1644
1645 /*
1646 * This decides which parts of a blame entry go to the parent (added to the
1647 * ignoredp list) and which stay with the target (added to the diffp list). The
1648 * actual decision was made in a separate heuristic function, and those answers
1649 * for the lines in 'e' are in line_blames. This consumes e, essentially
1650 * putting it on a list.
1651 *
1652 * Note that the blame entries on the ignoredp list are not necessarily sorted
1653 * with respect to the parent's line numbers yet.
1654 */
1655 static void ignore_blame_entry(struct blame_entry *e,
1656 struct blame_origin *parent,
1657 struct blame_entry **diffp,
1658 struct blame_entry **ignoredp,
1659 struct blame_line_tracker *line_blames)
1660 {
1661 int entry_len, nr_lines, i;
1662
1663 /*
1664 * We carve new entries off the front of e. Each entry comes from a
1665 * contiguous chunk of lines: adjacent lines from the same origin
1666 * (either the parent or the target).
1667 */
1668 entry_len = 1;
1669 nr_lines = e->num_lines; /* e changes in the loop */
1670 for (i = 0; i < nr_lines; i++) {
1671 struct blame_entry *next = NULL;
1672
1673 /*
1674 * We are often adjacent to the next line - only split the blame
1675 * entry when we have to.
1676 */
1677 if (i + 1 < nr_lines) {
1678 if (are_lines_adjacent(&line_blames[i],
1679 &line_blames[i + 1])) {
1680 entry_len++;
1681 continue;
1682 }
1683 next = split_blame_at(e, entry_len,
1684 blame_origin_incref(e->suspect));
1685 }
1686 if (line_blames[i].is_parent) {
1687 e->ignored = 1;
1688 blame_origin_decref(e->suspect);
1689 e->suspect = blame_origin_incref(parent);
1690 e->s_lno = line_blames[i - entry_len + 1].s_lno;
1691 e->next = *ignoredp;
1692 *ignoredp = e;
1693 } else {
1694 e->unblamable = 1;
1695 /* e->s_lno is already in the target's address space. */
1696 e->next = *diffp;
1697 *diffp = e;
1698 }
1699 assert(e->num_lines == entry_len);
1700 e = next;
1701 entry_len = 1;
1702 }
1703 assert(!e);
1704 }
1705
1706 /*
1707 * Process one hunk from the patch between the current suspect for
1708 * blame_entry e and its parent. This first blames any unfinished
1709 * entries before the chunk (which is where target and parent start
1710 * differing) on the parent, and then splits blame entries at the
1711 * start and at the end of the difference region. Since use of -M and
1712 * -C options may lead to overlapping/duplicate source line number
1713 * ranges, all we can rely on from sorting/merging is the order of the
1714 * first suspect line number.
1715 *
1716 * tlno: line number in the target where this chunk begins
1717 * same: line number in the target where this chunk ends
1718 * offset: add to tlno to get the chunk starting point in the parent
1719 * parent_len: number of lines in the parent chunk
1720 */
1721 static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
1722 int tlno, int offset, int same, int parent_len,
1723 struct blame_origin *parent,
1724 struct blame_origin *target, int ignore_diffs)
1725 {
1726 struct blame_entry *e = **srcq;
1727 struct blame_entry *samep = NULL, *diffp = NULL, *ignoredp = NULL;
1728 struct blame_line_tracker *line_blames = NULL;
1729
1730 while (e && e->s_lno < tlno) {
1731 struct blame_entry *next = e->next;
1732 /*
1733 * current record starts before differing portion. If
1734 * it reaches into it, we need to split it up and
1735 * examine the second part separately.
1736 */
1737 if (e->s_lno + e->num_lines > tlno) {
1738 /* Move second half to a new record */
1739 struct blame_entry *n;
1740
1741 n = split_blame_at(e, tlno - e->s_lno, e->suspect);
1742 /* Push new record to diffp */
1743 n->next = diffp;
1744 diffp = n;
1745 } else
1746 blame_origin_decref(e->suspect);
1747 /* Pass blame for everything before the differing
1748 * chunk to the parent */
1749 e->suspect = blame_origin_incref(parent);
1750 e->s_lno += offset;
1751 e->next = samep;
1752 samep = e;
1753 e = next;
1754 }
1755 /*
1756 * As we don't know how much of a common stretch after this
1757 * diff will occur, the currently blamed parts are all that we
1758 * can assign to the parent for now.
1759 */
1760
1761 if (samep) {
1762 **dstq = reverse_blame(samep, **dstq);
1763 *dstq = &samep->next;
1764 }
1765 /*
1766 * Prepend the split off portions: everything after e starts
1767 * after the blameable portion.
1768 */
1769 e = reverse_blame(diffp, e);
1770
1771 /*
1772 * Now retain records on the target while parts are different
1773 * from the parent.
1774 */
1775 samep = NULL;
1776 diffp = NULL;
1777
1778 if (ignore_diffs && same - tlno > 0) {
1779 line_blames = xcalloc(sizeof(struct blame_line_tracker),
1780 same - tlno);
1781 guess_line_blames(parent, target, tlno, offset, same,
1782 parent_len, line_blames);
1783 }
1784
1785 while (e && e->s_lno < same) {
1786 struct blame_entry *next = e->next;
1787
1788 /*
1789 * If current record extends into sameness, need to split.
1790 */
1791 if (e->s_lno + e->num_lines > same) {
1792 /*
1793 * Move second half to a new record to be
1794 * processed by later chunks
1795 */
1796 struct blame_entry *n;
1797
1798 n = split_blame_at(e, same - e->s_lno,
1799 blame_origin_incref(e->suspect));
1800 /* Push new record to samep */
1801 n->next = samep;
1802 samep = n;
1803 }
1804 if (ignore_diffs) {
1805 ignore_blame_entry(e, parent, &diffp, &ignoredp,
1806 line_blames + e->s_lno - tlno);
1807 } else {
1808 e->next = diffp;
1809 diffp = e;
1810 }
1811 e = next;
1812 }
1813 free(line_blames);
1814 if (ignoredp) {
1815 /*
1816 * Note ignoredp is not sorted yet, and thus neither is dstq.
1817 * That list must be sorted before we queue_blames(). We defer
1818 * sorting until after all diff hunks are processed, so that
1819 * guess_line_blames() can pick *any* line in the parent. The
1820 * slight drawback is that we end up sorting all blame entries
1821 * passed to the parent, including those that are unrelated to
1822 * changes made by the ignored commit.
1823 */
1824 **dstq = reverse_blame(ignoredp, **dstq);
1825 *dstq = &ignoredp->next;
1826 }
1827 **srcq = reverse_blame(diffp, reverse_blame(samep, e));
1828 /* Move across elements that are in the unblamable portion */
1829 if (diffp)
1830 *srcq = &diffp->next;
1831 }
1832
1833 struct blame_chunk_cb_data {
1834 struct blame_origin *parent;
1835 struct blame_origin *target;
1836 long offset;
1837 int ignore_diffs;
1838 struct blame_entry **dstq;
1839 struct blame_entry **srcq;
1840 };
1841
1842 /* diff chunks are from parent to target */
1843 static int blame_chunk_cb(long start_a, long count_a,
1844 long start_b, long count_b, void *data)
1845 {
1846 struct blame_chunk_cb_data *d = data;
1847 if (start_a - start_b != d->offset)
1848 die("internal error in blame::blame_chunk_cb");
1849 blame_chunk(&d->dstq, &d->srcq, start_b, start_a - start_b,
1850 start_b + count_b, count_a, d->parent, d->target,
1851 d->ignore_diffs);
1852 d->offset = start_a + count_a - (start_b + count_b);
1853 return 0;
1854 }
1855
1856 /*
1857 * We are looking at the origin 'target' and aiming to pass blame
1858 * for the lines it is suspected to its parent. Run diff to find
1859 * which lines came from parent and pass blame for them.
1860 */
1861 static void pass_blame_to_parent(struct blame_scoreboard *sb,
1862 struct blame_origin *target,
1863 struct blame_origin *parent, int ignore_diffs)
1864 {
1865 mmfile_t file_p, file_o;
1866 struct blame_chunk_cb_data d;
1867 struct blame_entry *newdest = NULL;
1868
1869 if (!target->suspects)
1870 return; /* nothing remains for this target */
1871
1872 d.parent = parent;
1873 d.target = target;
1874 d.offset = 0;
1875 d.ignore_diffs = ignore_diffs;
1876 d.dstq = &newdest; d.srcq = &target->suspects;
1877
1878 fill_origin_blob(&sb->revs->diffopt, parent, &file_p,
1879 &sb->num_read_blob, ignore_diffs);
1880 fill_origin_blob(&sb->revs->diffopt, target, &file_o,
1881 &sb->num_read_blob, ignore_diffs);
1882 sb->num_get_patch++;
1883
1884 if (diff_hunks(&file_p, &file_o, blame_chunk_cb, &d, sb->xdl_opts))
1885 die("unable to generate diff (%s -> %s)",
1886 oid_to_hex(&parent->commit->object.oid),
1887 oid_to_hex(&target->commit->object.oid));
1888 /* The rest are the same as the parent */
1889 blame_chunk(&d.dstq, &d.srcq, INT_MAX, d.offset, INT_MAX, 0,
1890 parent, target, 0);
1891 *d.dstq = NULL;
1892 if (ignore_diffs)
1893 newdest = llist_mergesort(newdest, get_next_blame,
1894 set_next_blame,
1895 compare_blame_suspect);
1896 queue_blames(sb, parent, newdest);
1897
1898 return;
1899 }
1900
1901 /*
1902 * The lines in blame_entry after splitting blames many times can become
1903 * very small and trivial, and at some point it becomes pointless to
1904 * blame the parents. E.g. "\t\t}\n\t}\n\n" appears everywhere in any
1905 * ordinary C program, and it is not worth to say it was copied from
1906 * totally unrelated file in the parent.
1907 *
1908 * Compute how trivial the lines in the blame_entry are.
1909 */
1910 unsigned blame_entry_score(struct blame_scoreboard *sb, struct blame_entry *e)
1911 {
1912 unsigned score;
1913 const char *cp, *ep;
1914
1915 if (e->score)
1916 return e->score;
1917
1918 score = 1;
1919 cp = blame_nth_line(sb, e->lno);
1920 ep = blame_nth_line(sb, e->lno + e->num_lines);
1921 while (cp < ep) {
1922 unsigned ch = *((unsigned char *)cp);
1923 if (isalnum(ch))
1924 score++;
1925 cp++;
1926 }
1927 e->score = score;
1928 return score;
1929 }
1930
1931 /*
1932 * best_so_far[] and potential[] are both a split of an existing blame_entry
1933 * that passes blame to the parent. Maintain best_so_far the best split so
1934 * far, by comparing potential and best_so_far and copying potential into
1935 * bst_so_far as needed.
1936 */
1937 static void copy_split_if_better(struct blame_scoreboard *sb,
1938 struct blame_entry *best_so_far,
1939 struct blame_entry *potential)
1940 {
1941 int i;
1942
1943 if (!potential[1].suspect)
1944 return;
1945 if (best_so_far[1].suspect) {
1946 if (blame_entry_score(sb, &potential[1]) <
1947 blame_entry_score(sb, &best_so_far[1]))
1948 return;
1949 }
1950
1951 for (i = 0; i < 3; i++)
1952 blame_origin_incref(potential[i].suspect);
1953 decref_split(best_so_far);
1954 memcpy(best_so_far, potential, sizeof(struct blame_entry[3]));
1955 }
1956
1957 /*
1958 * We are looking at a part of the final image represented by
1959 * ent (tlno and same are offset by ent->s_lno).
1960 * tlno is where we are looking at in the final image.
1961 * up to (but not including) same match preimage.
1962 * plno is where we are looking at in the preimage.
1963 *
1964 * <-------------- final image ---------------------->
1965 * <------ent------>
1966 * ^tlno ^same
1967 * <---------preimage----->
1968 * ^plno
1969 *
1970 * All line numbers are 0-based.
1971 */
1972 static void handle_split(struct blame_scoreboard *sb,
1973 struct blame_entry *ent,
1974 int tlno, int plno, int same,
1975 struct blame_origin *parent,
1976 struct blame_entry *split)
1977 {
1978 if (ent->num_lines <= tlno)
1979 return;
1980 if (tlno < same) {
1981 struct blame_entry potential[3];
1982 tlno += ent->s_lno;
1983 same += ent->s_lno;
1984 split_overlap(potential, ent, tlno, plno, same, parent);
1985 copy_split_if_better(sb, split, potential);
1986 decref_split(potential);
1987 }
1988 }
1989
1990 struct handle_split_cb_data {
1991 struct blame_scoreboard *sb;
1992 struct blame_entry *ent;
1993 struct blame_origin *parent;
1994 struct blame_entry *split;
1995 long plno;
1996 long tlno;
1997 };
1998
1999 static int handle_split_cb(long start_a, long count_a,
2000 long start_b, long count_b, void *data)
2001 {
2002 struct handle_split_cb_data *d = data;
2003 handle_split(d->sb, d->ent, d->tlno, d->plno, start_b, d->parent,
2004 d->split);
2005 d->plno = start_a + count_a;
2006 d->tlno = start_b + count_b;
2007 return 0;
2008 }
2009
2010 /*
2011 * Find the lines from parent that are the same as ent so that
2012 * we can pass blames to it. file_p has the blob contents for
2013 * the parent.
2014 */
2015 static void find_copy_in_blob(struct blame_scoreboard *sb,
2016 struct blame_entry *ent,
2017 struct blame_origin *parent,
2018 struct blame_entry *split,
2019 mmfile_t *file_p)
2020 {
2021 const char *cp;
2022 mmfile_t file_o;
2023 struct handle_split_cb_data d;
2024
2025 memset(&d, 0, sizeof(d));
2026 d.sb = sb; d.ent = ent; d.parent = parent; d.split = split;
2027 /*
2028 * Prepare mmfile that contains only the lines in ent.
2029 */
2030 cp = blame_nth_line(sb, ent->lno);
2031 file_o.ptr = (char *) cp;
2032 file_o.size = blame_nth_line(sb, ent->lno + ent->num_lines) - cp;
2033
2034 /*
2035 * file_o is a part of final image we are annotating.
2036 * file_p partially may match that image.
2037 */
2038 memset(split, 0, sizeof(struct blame_entry [3]));
2039 if (diff_hunks(file_p, &file_o, handle_split_cb, &d, sb->xdl_opts))
2040 die("unable to generate diff (%s)",
2041 oid_to_hex(&parent->commit->object.oid));
2042 /* remainder, if any, all match the preimage */
2043 handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split);
2044 }
2045
2046 /* Move all blame entries from list *source that have a score smaller
2047 * than score_min to the front of list *small.
2048 * Returns a pointer to the link pointing to the old head of the small list.
2049 */
2050
2051 static struct blame_entry **filter_small(struct blame_scoreboard *sb,
2052 struct blame_entry **small,
2053 struct blame_entry **source,
2054 unsigned score_min)
2055 {
2056 struct blame_entry *p = *source;
2057 struct blame_entry *oldsmall = *small;
2058 while (p) {
2059 if (blame_entry_score(sb, p) <= score_min) {
2060 *small = p;
2061 small = &p->next;
2062 p = *small;
2063 } else {
2064 *source = p;
2065 source = &p->next;
2066 p = *source;
2067 }
2068 }
2069 *small = oldsmall;
2070 *source = NULL;
2071 return small;
2072 }
2073
2074 /*
2075 * See if lines currently target is suspected for can be attributed to
2076 * parent.
2077 */
2078 static void find_move_in_parent(struct blame_scoreboard *sb,
2079 struct blame_entry ***blamed,
2080 struct blame_entry **toosmall,
2081 struct blame_origin *target,
2082 struct blame_origin *parent)
2083 {
2084 struct blame_entry *e, split[3];
2085 struct blame_entry *unblamed = target->suspects;
2086 struct blame_entry *leftover = NULL;
2087 mmfile_t file_p;
2088
2089 if (!unblamed)
2090 return; /* nothing remains for this target */
2091
2092 fill_origin_blob(&sb->revs->diffopt, parent, &file_p,
2093 &sb->num_read_blob, 0);
2094 if (!file_p.ptr)
2095 return;
2096
2097 /* At each iteration, unblamed has a NULL-terminated list of
2098 * entries that have not yet been tested for blame. leftover
2099 * contains the reversed list of entries that have been tested
2100 * without being assignable to the parent.
2101 */
2102 do {
2103 struct blame_entry **unblamedtail = &unblamed;
2104 struct blame_entry *next;
2105 for (e = unblamed; e; e = next) {
2106 next = e->next;
2107 find_copy_in_blob(sb, e, parent, split, &file_p);
2108 if (split[1].suspect &&
2109 sb->move_score < blame_entry_score(sb, &split[1])) {
2110 split_blame(blamed, &unblamedtail, split, e);
2111 } else {
2112 e->next = leftover;
2113 leftover = e;
2114 }
2115 decref_split(split);
2116 }
2117 *unblamedtail = NULL;
2118 toosmall = filter_small(sb, toosmall, &unblamed, sb->move_score);
2119 } while (unblamed);
2120 target->suspects = reverse_blame(leftover, NULL);
2121 }
2122
2123 struct blame_list {
2124 struct blame_entry *ent;
2125 struct blame_entry split[3];
2126 };
2127
2128 /*
2129 * Count the number of entries the target is suspected for,
2130 * and prepare a list of entry and the best split.
2131 */
2132 static struct blame_list *setup_blame_list(struct blame_entry *unblamed,
2133 int *num_ents_p)
2134 {
2135 struct blame_entry *e;
2136 int num_ents, i;
2137 struct blame_list *blame_list = NULL;
2138
2139 for (e = unblamed, num_ents = 0; e; e = e->next)
2140 num_ents++;
2141 if (num_ents) {
2142 blame_list = xcalloc(num_ents, sizeof(struct blame_list));
2143 for (e = unblamed, i = 0; e; e = e->next)
2144 blame_list[i++].ent = e;
2145 }
2146 *num_ents_p = num_ents;
2147 return blame_list;
2148 }
2149
2150 /*
2151 * For lines target is suspected for, see if we can find code movement
2152 * across file boundary from the parent commit. porigin is the path
2153 * in the parent we already tried.
2154 */
2155 static void find_copy_in_parent(struct blame_scoreboard *sb,
2156 struct blame_entry ***blamed,
2157 struct blame_entry **toosmall,
2158 struct blame_origin *target,
2159 struct commit *parent,
2160 struct blame_origin *porigin,
2161 int opt)
2162 {
2163 struct diff_options diff_opts;
2164 int i, j;
2165 struct blame_list *blame_list;
2166 int num_ents;
2167 struct blame_entry *unblamed = target->suspects;
2168 struct blame_entry *leftover = NULL;
2169
2170 if (!unblamed)
2171 return; /* nothing remains for this target */
2172
2173 repo_diff_setup(sb->repo, &diff_opts);
2174 diff_opts.flags.recursive = 1;
2175 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
2176
2177 diff_setup_done(&diff_opts);
2178
2179 /* Try "find copies harder" on new path if requested;
2180 * we do not want to use diffcore_rename() actually to
2181 * match things up; find_copies_harder is set only to
2182 * force diff_tree_oid() to feed all filepairs to diff_queue,
2183 * and this code needs to be after diff_setup_done(), which
2184 * usually makes find-copies-harder imply copy detection.
2185 */
2186 if ((opt & PICKAXE_BLAME_COPY_HARDEST)
2187 || ((opt & PICKAXE_BLAME_COPY_HARDER)
2188 && (!porigin || strcmp(target->path, porigin->path))))
2189 diff_opts.flags.find_copies_harder = 1;
2190
2191 if (is_null_oid(&target->commit->object.oid))
2192 do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
2193 else
2194 diff_tree_oid(get_commit_tree_oid(parent),
2195 get_commit_tree_oid(target->commit),
2196 "", &diff_opts);
2197
2198 if (!diff_opts.flags.find_copies_harder)
2199 diffcore_std(&diff_opts);
2200
2201 do {
2202 struct blame_entry **unblamedtail = &unblamed;
2203 blame_list = setup_blame_list(unblamed, &num_ents);
2204
2205 for (i = 0; i < diff_queued_diff.nr; i++) {
2206 struct diff_filepair *p = diff_queued_diff.queue[i];
2207 struct blame_origin *norigin;
2208 mmfile_t file_p;
2209 struct blame_entry potential[3];
2210
2211 if (!DIFF_FILE_VALID(p->one))
2212 continue; /* does not exist in parent */
2213 if (S_ISGITLINK(p->one->mode))
2214 continue; /* ignore git links */
2215 if (porigin && !strcmp(p->one->path, porigin->path))
2216 /* find_move already dealt with this path */
2217 continue;
2218
2219 norigin = get_origin(parent, p->one->path);
2220 oidcpy(&norigin->blob_oid, &p->one->oid);
2221 norigin->mode = p->one->mode;
2222 fill_origin_blob(&sb->revs->diffopt, norigin, &file_p,
2223 &sb->num_read_blob, 0);
2224 if (!file_p.ptr)
2225 continue;
2226
2227 for (j = 0; j < num_ents; j++) {
2228 find_copy_in_blob(sb, blame_list[j].ent,
2229 norigin, potential, &file_p);
2230 copy_split_if_better(sb, blame_list[j].split,
2231 potential);
2232 decref_split(potential);
2233 }
2234 blame_origin_decref(norigin);
2235 }
2236
2237 for (j = 0; j < num_ents; j++) {
2238 struct blame_entry *split = blame_list[j].split;
2239 if (split[1].suspect &&
2240 sb->copy_score < blame_entry_score(sb, &split[1])) {
2241 split_blame(blamed, &unblamedtail, split,
2242 blame_list[j].ent);
2243 } else {
2244 blame_list[j].ent->next = leftover;
2245 leftover = blame_list[j].ent;
2246 }
2247 decref_split(split);
2248 }
2249 free(blame_list);
2250 *unblamedtail = NULL;
2251 toosmall = filter_small(sb, toosmall, &unblamed, sb->copy_score);
2252 } while (unblamed);
2253 target->suspects = reverse_blame(leftover, NULL);
2254 diff_flush(&diff_opts);
2255 clear_pathspec(&diff_opts.pathspec);
2256 }
2257
2258 /*
2259 * The blobs of origin and porigin exactly match, so everything
2260 * origin is suspected for can be blamed on the parent.
2261 */
2262 static void pass_whole_blame(struct blame_scoreboard *sb,
2263 struct blame_origin *origin, struct blame_origin *porigin)
2264 {
2265 struct blame_entry *e, *suspects;
2266
2267 if (!porigin->file.ptr && origin->file.ptr) {
2268 /* Steal its file */
2269 porigin->file = origin->file;
2270 origin->file.ptr = NULL;
2271 }
2272 suspects = origin->suspects;
2273 origin->suspects = NULL;
2274 for (e = suspects; e; e = e->next) {
2275 blame_origin_incref(porigin);
2276 blame_origin_decref(e->suspect);
2277 e->suspect = porigin;
2278 }
2279 queue_blames(sb, porigin, suspects);
2280 }
2281
2282 /*
2283 * We pass blame from the current commit to its parents. We keep saying
2284 * "parent" (and "porigin"), but what we mean is to find scapegoat to
2285 * exonerate ourselves.
2286 */
2287 static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit,
2288 int reverse)
2289 {
2290 if (!reverse) {
2291 if (revs->first_parent_only &&
2292 commit->parents &&
2293 commit->parents->next) {
2294 free_commit_list(commit->parents->next);
2295 commit->parents->next = NULL;
2296 }
2297 return commit->parents;
2298 }
2299 return lookup_decoration(&revs->children, &commit->object);
2300 }
2301
2302 static int num_scapegoats(struct rev_info *revs, struct commit *commit, int reverse)
2303 {
2304 struct commit_list *l = first_scapegoat(revs, commit, reverse);
2305 return commit_list_count(l);
2306 }
2307
2308 /* Distribute collected unsorted blames to the respected sorted lists
2309 * in the various origins.
2310 */
2311 static void distribute_blame(struct blame_scoreboard *sb, struct blame_entry *blamed)
2312 {
2313 blamed = llist_mergesort(blamed, get_next_blame, set_next_blame,
2314 compare_blame_suspect);
2315 while (blamed)
2316 {
2317 struct blame_origin *porigin = blamed->suspect;
2318 struct blame_entry *suspects = NULL;
2319 do {
2320 struct blame_entry *next = blamed->next;
2321 blamed->next = suspects;
2322 suspects = blamed;
2323 blamed = next;
2324 } while (blamed && blamed->suspect == porigin);
2325 suspects = reverse_blame(suspects, NULL);
2326 queue_blames(sb, porigin, suspects);
2327 }
2328 }
2329
2330 #define MAXSG 16
2331
2332 static void pass_blame(struct blame_scoreboard *sb, struct blame_origin *origin, int opt)
2333 {
2334 struct rev_info *revs = sb->revs;
2335 int i, pass, num_sg;
2336 struct commit *commit = origin->commit;
2337 struct commit_list *sg;
2338 struct blame_origin *sg_buf[MAXSG];
2339 struct blame_origin *porigin, **sg_origin = sg_buf;
2340 struct blame_entry *toosmall = NULL;
2341 struct blame_entry *blames, **blametail = &blames;
2342
2343 num_sg = num_scapegoats(revs, commit, sb->reverse);
2344 if (!num_sg)
2345 goto finish;
2346 else if (num_sg < ARRAY_SIZE(sg_buf))
2347 memset(sg_buf, 0, sizeof(sg_buf));
2348 else
2349 sg_origin = xcalloc(num_sg, sizeof(*sg_origin));
2350
2351 /*
2352 * The first pass looks for unrenamed path to optimize for
2353 * common cases, then we look for renames in the second pass.
2354 */
2355 for (pass = 0; pass < 2 - sb->no_whole_file_rename; pass++) {
2356 struct blame_origin *(*find)(struct repository *, struct commit *, struct blame_origin *);
2357 find = pass ? find_rename : find_origin;
2358
2359 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
2360 i < num_sg && sg;
2361 sg = sg->next, i++) {
2362 struct commit *p = sg->item;
2363 int j, same;
2364
2365 if (sg_origin[i])
2366 continue;
2367 if (parse_commit(p))
2368 continue;
2369 porigin = find(sb->repo, p, origin);
2370 if (!porigin)
2371 continue;
2372 if (oideq(&porigin->blob_oid, &origin->blob_oid)) {
2373 pass_whole_blame(sb, origin, porigin);
2374 blame_origin_decref(porigin);
2375 goto finish;
2376 }
2377 for (j = same = 0; j < i; j++)
2378 if (sg_origin[j] &&
2379 oideq(&sg_origin[j]->blob_oid, &porigin->blob_oid)) {
2380 same = 1;
2381 break;
2382 }
2383 if (!same)
2384 sg_origin[i] = porigin;
2385 else
2386 blame_origin_decref(porigin);
2387 }
2388 }
2389
2390 sb->num_commits++;
2391 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
2392 i < num_sg && sg;
2393 sg = sg->next, i++) {
2394 struct blame_origin *porigin = sg_origin[i];
2395 if (!porigin)
2396 continue;
2397 if (!origin->previous) {
2398 blame_origin_incref(porigin);
2399 origin->previous = porigin;
2400 }
2401 pass_blame_to_parent(sb, origin, porigin, 0);
2402 if (!origin->suspects)
2403 goto finish;
2404 }
2405
2406 /*
2407 * Pass remaining suspects for ignored commits to their parents.
2408 */
2409 if (oidset_contains(&sb->ignore_list, &commit->object.oid)) {
2410 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
2411 i < num_sg && sg;
2412 sg = sg->next, i++) {
2413 struct blame_origin *porigin = sg_origin[i];
2414
2415 if (!porigin)
2416 continue;
2417 pass_blame_to_parent(sb, origin, porigin, 1);
2418 /*
2419 * Preemptively drop porigin so we can refresh the
2420 * fingerprints if we use the parent again, which can
2421 * occur if you ignore back-to-back commits.
2422 */
2423 drop_origin_blob(porigin);
2424 if (!origin->suspects)
2425 goto finish;
2426 }
2427 }
2428
2429 /*
2430 * Optionally find moves in parents' files.
2431 */
2432 if (opt & PICKAXE_BLAME_MOVE) {
2433 filter_small(sb, &toosmall, &origin->suspects, sb->move_score);
2434 if (origin->suspects) {
2435 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
2436 i < num_sg && sg;
2437 sg = sg->next, i++) {
2438 struct blame_origin *porigin = sg_origin[i];
2439 if (!porigin)
2440 continue;
2441 find_move_in_parent(sb, &blametail, &toosmall, origin, porigin);
2442 if (!origin->suspects)
2443 break;
2444 }
2445 }
2446 }
2447
2448 /*
2449 * Optionally find copies from parents' files.
2450 */
2451 if (opt & PICKAXE_BLAME_COPY) {
2452 if (sb->copy_score > sb->move_score)
2453 filter_small(sb, &toosmall, &origin->suspects, sb->copy_score);
2454 else if (sb->copy_score < sb->move_score) {
2455 origin->suspects = blame_merge(origin->suspects, toosmall);
2456 toosmall = NULL;
2457 filter_small(sb, &toosmall, &origin->suspects, sb->copy_score);
2458 }
2459 if (!origin->suspects)
2460 goto finish;
2461
2462 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
2463 i < num_sg && sg;
2464 sg = sg->next, i++) {
2465 struct blame_origin *porigin = sg_origin[i];
2466 find_copy_in_parent(sb, &blametail, &toosmall,
2467 origin, sg->item, porigin, opt);
2468 if (!origin->suspects)
2469 goto finish;
2470 }
2471 }
2472
2473 finish:
2474 *blametail = NULL;
2475 distribute_blame(sb, blames);
2476 /*
2477 * prepend toosmall to origin->suspects
2478 *
2479 * There is no point in sorting: this ends up on a big
2480 * unsorted list in the caller anyway.
2481 */
2482 if (toosmall) {
2483 struct blame_entry **tail = &toosmall;
2484 while (*tail)
2485 tail = &(*tail)->next;
2486 *tail = origin->suspects;
2487 origin->suspects = toosmall;
2488 }
2489 for (i = 0; i < num_sg; i++) {
2490 if (sg_origin[i]) {
2491 if (!sg_origin[i]->suspects)
2492 drop_origin_blob(sg_origin[i]);
2493 blame_origin_decref(sg_origin[i]);
2494 }
2495 }
2496 drop_origin_blob(origin);
2497 if (sg_buf != sg_origin)
2498 free(sg_origin);
2499 }
2500
2501 /*
2502 * The main loop -- while we have blobs with lines whose true origin
2503 * is still unknown, pick one blob, and allow its lines to pass blames
2504 * to its parents. */
2505 void assign_blame(struct blame_scoreboard *sb, int opt)
2506 {
2507 struct rev_info *revs = sb->revs;
2508 struct commit *commit = prio_queue_get(&sb->commits);
2509
2510 while (commit) {
2511 struct blame_entry *ent;
2512 struct blame_origin *suspect = get_blame_suspects(commit);
2513
2514 /* find one suspect to break down */
2515 while (suspect && !suspect->suspects)
2516 suspect = suspect->next;
2517
2518 if (!suspect) {
2519 commit = prio_queue_get(&sb->commits);
2520 continue;
2521 }
2522
2523 assert(commit == suspect->commit);
2524
2525 /*
2526 * We will use this suspect later in the loop,
2527 * so hold onto it in the meantime.
2528 */
2529 blame_origin_incref(suspect);
2530 parse_commit(commit);
2531 if (sb->reverse ||
2532 (!(commit->object.flags & UNINTERESTING) &&
2533 !(revs->max_age != -1 && commit->date < revs->max_age)))
2534 pass_blame(sb, suspect, opt);
2535 else {
2536 commit->object.flags |= UNINTERESTING;
2537 if (commit->object.parsed)
2538 mark_parents_uninteresting(commit);
2539 }
2540 /* treat root commit as boundary */
2541 if (!commit->parents && !sb->show_root)
2542 commit->object.flags |= UNINTERESTING;
2543
2544 /* Take responsibility for the remaining entries */
2545 ent = suspect->suspects;
2546 if (ent) {
2547 suspect->guilty = 1;
2548 for (;;) {
2549 struct blame_entry *next = ent->next;
2550 if (sb->found_guilty_entry)
2551 sb->found_guilty_entry(ent, sb->found_guilty_entry_data);
2552 if (next) {
2553 ent = next;
2554 continue;
2555 }
2556 ent->next = sb->ent;
2557 sb->ent = suspect->suspects;
2558 suspect->suspects = NULL;
2559 break;
2560 }
2561 }
2562 blame_origin_decref(suspect);
2563
2564 if (sb->debug) /* sanity */
2565 sanity_check_refcnt(sb);
2566 }
2567 }
2568
2569 /*
2570 * To allow quick access to the contents of nth line in the
2571 * final image, prepare an index in the scoreboard.
2572 */
2573 static int prepare_lines(struct blame_scoreboard *sb)
2574 {
2575 sb->num_lines = find_line_starts(&sb->lineno, sb->final_buf,
2576 sb->final_buf_size);
2577 return sb->num_lines;
2578 }
2579
2580 static struct commit *find_single_final(struct rev_info *revs,
2581 const char **name_p)
2582 {
2583 int i;
2584 struct commit *found = NULL;
2585 const char *name = NULL;
2586
2587 for (i = 0; i < revs->pending.nr; i++) {
2588 struct object *obj = revs->pending.objects[i].item;
2589 if (obj->flags & UNINTERESTING)
2590 continue;
2591 obj = deref_tag(revs->repo, obj, NULL, 0);
2592 if (obj->type != OBJ_COMMIT)
2593 die("Non commit %s?", revs->pending.objects[i].name);
2594 if (found)
2595 die("More than one commit to dig from %s and %s?",
2596 revs->pending.objects[i].name, name);
2597 found = (struct commit *)obj;
2598 name = revs->pending.objects[i].name;
2599 }
2600 if (name_p)
2601 *name_p = xstrdup_or_null(name);
2602 return found;
2603 }
2604
2605 static struct commit *dwim_reverse_initial(struct rev_info *revs,
2606 const char **name_p)
2607 {
2608 /*
2609 * DWIM "git blame --reverse ONE -- PATH" as
2610 * "git blame --reverse ONE..HEAD -- PATH" but only do so
2611 * when it makes sense.
2612 */
2613 struct object *obj;
2614 struct commit *head_commit;
2615 struct object_id head_oid;
2616
2617 if (revs->pending.nr != 1)
2618 return NULL;
2619
2620 /* Is that sole rev a committish? */
2621 obj = revs->pending.objects[0].item;
2622 obj = deref_tag(revs->repo, obj, NULL, 0);
2623 if (obj->type != OBJ_COMMIT)
2624 return NULL;
2625
2626 /* Do we have HEAD? */
2627 if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
2628 return NULL;
2629 head_commit = lookup_commit_reference_gently(revs->repo,
2630 &head_oid, 1);
2631 if (!head_commit)
2632 return NULL;
2633
2634 /* Turn "ONE" into "ONE..HEAD" then */
2635 obj->flags |= UNINTERESTING;
2636 add_pending_object(revs, &head_commit->object, "HEAD");
2637
2638 if (name_p)
2639 *name_p = revs->pending.objects[0].name;
2640 return (struct commit *)obj;
2641 }
2642
2643 static struct commit *find_single_initial(struct rev_info *revs,
2644 const char **name_p)
2645 {
2646 int i;
2647 struct commit *found = NULL;
2648 const char *name = NULL;
2649
2650 /*
2651 * There must be one and only one negative commit, and it must be
2652 * the boundary.
2653 */
2654 for (i = 0; i < revs->pending.nr; i++) {
2655 struct object *obj = revs->pending.objects[i].item;
2656 if (!(obj->flags & UNINTERESTING))
2657 continue;
2658 obj = deref_tag(revs->repo, obj, NULL, 0);
2659 if (obj->type != OBJ_COMMIT)
2660 die("Non commit %s?", revs->pending.objects[i].name);
2661 if (found)
2662 die("More than one commit to dig up from, %s and %s?",
2663 revs->pending.objects[i].name, name);
2664 found = (struct commit *) obj;
2665 name = revs->pending.objects[i].name;
2666 }
2667
2668 if (!name)
2669 found = dwim_reverse_initial(revs, &name);
2670 if (!name)
2671 die("No commit to dig up from?");
2672
2673 if (name_p)
2674 *name_p = xstrdup(name);
2675 return found;
2676 }
2677
2678 void init_scoreboard(struct blame_scoreboard *sb)
2679 {
2680 memset(sb, 0, sizeof(struct blame_scoreboard));
2681 sb->move_score = BLAME_DEFAULT_MOVE_SCORE;
2682 sb->copy_score = BLAME_DEFAULT_COPY_SCORE;
2683 }
2684
2685 void setup_scoreboard(struct blame_scoreboard *sb,
2686 const char *path,
2687 struct blame_origin **orig)
2688 {
2689 const char *final_commit_name = NULL;
2690 struct blame_origin *o;
2691 struct commit *final_commit = NULL;
2692 enum object_type type;
2693
2694 init_blame_suspects(&blame_suspects);
2695
2696 if (sb->reverse && sb->contents_from)
2697 die(_("--contents and --reverse do not blend well."));
2698
2699 if (!sb->repo)
2700 BUG("repo is NULL");
2701
2702 if (!sb->reverse) {
2703 sb->final = find_single_final(sb->revs, &final_commit_name);
2704 sb->commits.compare = compare_commits_by_commit_date;
2705 } else {
2706 sb->final = find_single_initial(sb->revs, &final_commit_name);
2707 sb->commits.compare = compare_commits_by_reverse_commit_date;
2708 }
2709
2710 if (sb->final && sb->contents_from)
2711 die(_("cannot use --contents with final commit object name"));
2712
2713 if (sb->reverse && sb->revs->first_parent_only)
2714 sb->revs->children.name = NULL;
2715
2716 if (!sb->final) {
2717 /*
2718 * "--not A B -- path" without anything positive;
2719 * do not default to HEAD, but use the working tree
2720 * or "--contents".
2721 */
2722 setup_work_tree();
2723 sb->final = fake_working_tree_commit(sb->repo,
2724 &sb->revs->diffopt,
2725 path, sb->contents_from);
2726 add_pending_object(sb->revs, &(sb->final->object), ":");
2727 }
2728
2729 if (sb->reverse && sb->revs->first_parent_only) {
2730 final_commit = find_single_final(sb->revs, NULL);
2731 if (!final_commit)
2732 die(_("--reverse and --first-parent together require specified latest commit"));
2733 }
2734
2735 /*
2736 * If we have bottom, this will mark the ancestors of the
2737 * bottom commits we would reach while traversing as
2738 * uninteresting.
2739 */
2740 if (prepare_revision_walk(sb->revs))
2741 die(_("revision walk setup failed"));
2742
2743 if (sb->reverse && sb->revs->first_parent_only) {
2744 struct commit *c = final_commit;
2745
2746 sb->revs->children.name = "children";
2747 while (c->parents &&
2748 !oideq(&c->object.oid, &sb->final->object.oid)) {
2749 struct commit_list *l = xcalloc(1, sizeof(*l));
2750
2751 l->item = c;
2752 if (add_decoration(&sb->revs->children,
2753 &c->parents->item->object, l))
2754 BUG("not unique item in first-parent chain");
2755 c = c->parents->item;
2756 }
2757
2758 if (!oideq(&c->object.oid, &sb->final->object.oid))
2759 die(_("--reverse --first-parent together require range along first-parent chain"));
2760 }
2761
2762 if (is_null_oid(&sb->final->object.oid)) {
2763 o = get_blame_suspects(sb->final);
2764 sb->final_buf = xmemdupz(o->file.ptr, o->file.size);
2765 sb->final_buf_size = o->file.size;
2766 }
2767 else {
2768 o = get_origin(sb->final, path);
2769 if (fill_blob_sha1_and_mode(sb->repo, o))
2770 die(_("no such path %s in %s"), path, final_commit_name);
2771
2772 if (sb->revs->diffopt.flags.allow_textconv &&
2773 textconv_object(sb->repo, path, o->mode, &o->blob_oid, 1, (char **) &sb->final_buf,
2774 &sb->final_buf_size))
2775 ;
2776 else
2777 sb->final_buf = read_object_file(&o->blob_oid, &type,
2778 &sb->final_buf_size);
2779
2780 if (!sb->final_buf)
2781 die(_("cannot read blob %s for path %s"),
2782 oid_to_hex(&o->blob_oid),
2783 path);
2784 }
2785 sb->num_read_blob++;
2786 prepare_lines(sb);
2787
2788 if (orig)
2789 *orig = o;
2790
2791 free((char *)final_commit_name);
2792 }
2793
2794
2795
2796 struct blame_entry *blame_entry_prepend(struct blame_entry *head,
2797 long start, long end,
2798 struct blame_origin *o)
2799 {
2800 struct blame_entry *new_head = xcalloc(1, sizeof(struct blame_entry));
2801 new_head->lno = start;
2802 new_head->num_lines = end - start;
2803 new_head->suspect = o;
2804 new_head->s_lno = start;
2805 new_head->next = head;
2806 blame_origin_incref(o);
2807 return new_head;
2808 }