promisor-remote: skip move_to_tail when no-op
[git/git.git] / blame.c
CommitLineData
072bf432
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1#include "cache.h"
2#include "refs.h"
cbd53a21 3#include "object-store.h"
072bf432 4#include "cache-tree.h"
b543bb1c
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5#include "mergesort.h"
6#include "diff.h"
7#include "diffcore.h"
09002f1b 8#include "tag.h"
f5dd754c 9#include "blame.h"
14ba97f8 10#include "alloc.h"
4e0df4e6
NTND
11#include "commit-slab.h"
12
13define_commit_slab(blame_suspects, struct blame_origin *);
14static struct blame_suspects blame_suspects;
15
16struct 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
25static void set_blame_suspects(struct commit *commit, struct blame_origin *origin)
26{
27 *blame_suspects_at(&blame_suspects, commit) = origin;
28}
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29
30void 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 */
4e0df4e6 38 for (p = get_blame_suspects(o->commit); p; l = p, p = p->next) {
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39 if (p == o) {
40 if (l)
41 l->next = p->next;
42 else
4e0df4e6 43 set_blame_suspects(o->commit, p->next);
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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 */
072bf432 58static struct blame_origin *make_origin(struct commit *commit, const char *path)
f5dd754c
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59{
60 struct blame_origin *o;
61 FLEX_ALLOC_STR(o, path, path);
62 o->commit = commit;
63 o->refcnt = 1;
4e0df4e6
NTND
64 o->next = get_blame_suspects(commit);
65 set_blame_suspects(commit, o);
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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 */
09002f1b 73static struct blame_origin *get_origin(struct commit *commit, const char *path)
f5dd754c
JS
74{
75 struct blame_origin *o, *l;
76
4e0df4e6 77 for (o = get_blame_suspects(commit), l = NULL; o; l = o, o = o->next) {
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78 if (!strcmp(o->path, path)) {
79 /* bump to front */
80 if (l) {
81 l->next = o->next;
4e0df4e6
NTND
82 o->next = get_blame_suspects(commit);
83 set_blame_suspects(commit, o);
f5dd754c
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84 }
85 return blame_origin_incref(o);
86 }
87 }
88 return make_origin(commit, path);
89}
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90
91
92
a470beea 93static void verify_working_tree_path(struct repository *r,
ecbbc0a5 94 struct commit *work_tree, const char *path)
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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;
5ec1e728 102 unsigned short mode;
072bf432 103
916bc35b 104 if (!get_tree_entry(commit_oid, path, &blob_oid, &mode) &&
a470beea 105 oid_object_info(r, &blob_oid, NULL) == OBJ_BLOB)
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106 return;
107 }
108
a470beea 109 pos = index_name_pos(r->index, path, strlen(path));
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110 if (pos >= 0)
111 ; /* path is in the index */
a470beea
NTND
112 else if (-1 - pos < r->index->cache_nr &&
113 !strcmp(r->index->cache[-1 - pos]->name, path))
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114 ; /* path is in the index, unmerged */
115 else
116 die("no such path '%s' in HEAD", path);
117}
118
fb998eae
NTND
119static struct commit_list **append_parent(struct repository *r,
120 struct commit_list **tail,
121 const struct object_id *oid)
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122{
123 struct commit *parent;
124
fb998eae 125 parent = lookup_commit_reference(r, oid);
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126 if (!parent)
127 die("no such commit %s", oid_to_hex(oid));
128 return &commit_list_insert(parent, tail)->next;
129}
130
fb998eae
NTND
131static void append_merge_parents(struct repository *r,
132 struct commit_list **tail)
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133{
134 int merge_head;
135 struct strbuf line = STRBUF_INIT;
136
fb998eae 137 merge_head = open(git_path_merge_head(r), O_RDONLY);
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138 if (merge_head < 0) {
139 if (errno == ENOENT)
140 return;
102de880 141 die("cannot open '%s' for reading",
fb998eae 142 git_path_merge_head(r));
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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))
102de880 148 die("unknown line in '%s': %s",
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NTND
149 git_path_merge_head(r), line.buf);
150 tail = append_parent(r, tail, &oid);
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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 */
fb998eae
NTND
161static void set_commit_buffer_from_strbuf(struct repository *r,
162 struct commit *c,
163 struct strbuf *sb)
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164{
165 size_t len;
166 void *buf = strbuf_detach(sb, &len);
fb998eae 167 set_commit_buffer(r, c, buf, len);
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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 */
a470beea 174static struct commit *fake_working_tree_commit(struct repository *r,
ecbbc0a5 175 struct diff_options *opt,
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JS
176 const char *path,
177 const char *contents_from)
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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;
a849735b 186 int len;
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187 struct cache_entry *ce;
188 unsigned mode;
189 struct strbuf msg = STRBUF_INIT;
190
e1ff0a32 191 repo_read_index(r);
072bf432 192 time(&now);
fb998eae 193 commit = alloc_commit_node(r);
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194 commit->object.parsed = 1;
195 commit->date = now;
196 parent_tail = &commit->parents;
197
49e61479 198 if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
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199 die("no such ref: HEAD");
200
fb998eae
NTND
201 parent_tail = append_parent(r, parent_tail, &head_oid);
202 append_merge_parents(r, parent_tail);
a470beea 203 verify_working_tree_path(r, commit, path);
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204
205 origin = make_origin(commit, path);
206
39ab4d09
WH
207 ident = fmt_ident("Not Committed Yet", "not.committed.yet",
208 WANT_BLANK_IDENT, NULL, 0);
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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)));
fb998eae 220 set_commit_buffer_from_strbuf(r, commit, &msg);
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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:
0d1e0e78 242 if (opt->flags.allow_textconv &&
6afaf807 243 textconv_object(r, read_from, mode, &null_oid, 0, &buf_ptr, &buf_len))
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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 }
a470beea 262 convert_to_git(r->index, path, buf.buf, buf.len, &buf, 0);
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JS
263 origin->file.ptr = buf.buf;
264 origin->file.size = buf.len;
829e5c3b 265 pretend_object_file(buf.buf, buf.len, OBJ_BLOB, &origin->blob_oid);
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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 */
a470beea 273 discard_index(r->index);
e1ff0a32 274 repo_read_index(r);
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275
276 len = strlen(path);
277 if (!mode) {
a470beea 278 int pos = index_name_pos(r->index, path, len);
072bf432 279 if (0 <= pos)
a470beea 280 mode = r->index->cache[pos]->ce_mode;
072bf432
JS
281 else
282 /* Let's not bother reading from HEAD tree */
283 mode = S_IFREG | 0644;
284 }
a470beea 285 ce = make_empty_cache_entry(r->index, len);
072bf432
JS
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);
a470beea 291 add_index_entry(r->index, ce,
ecbbc0a5 292 ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
072bf432 293
a470beea 294 cache_tree_invalidate_path(r->index, path);
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295
296 return commit;
297}
b543bb1c
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298
299
300
301static 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/*
315 * Given an origin, prepare mmfile_t structure to be used by the
316 * diff machinery
317 */
318static void fill_origin_blob(struct diff_options *opt,
319 struct blame_origin *o, mmfile_t *file, int *num_read_blob)
320{
321 if (!o->file.ptr) {
322 enum object_type type;
323 unsigned long file_size;
324
325 (*num_read_blob)++;
0d1e0e78 326 if (opt->flags.allow_textconv &&
6afaf807
NTND
327 textconv_object(opt->repo, o->path, o->mode,
328 &o->blob_oid, 1, &file->ptr, &file_size))
b543bb1c
JS
329 ;
330 else
b4f5aca4 331 file->ptr = read_object_file(&o->blob_oid, &type,
332 &file_size);
b543bb1c
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333 file->size = file_size;
334
335 if (!file->ptr)
336 die("Cannot read blob %s for path %s",
337 oid_to_hex(&o->blob_oid),
338 o->path);
339 o->file = *file;
340 }
341 else
342 *file = o->file;
343}
344
345static void drop_origin_blob(struct blame_origin *o)
346{
ce528de0 347 FREE_AND_NULL(o->file.ptr);
b543bb1c
JS
348}
349
350/*
351 * Any merge of blames happens on lists of blames that arrived via
352 * different parents in a single suspect. In this case, we want to
353 * sort according to the suspect line numbers as opposed to the final
354 * image line numbers. The function body is somewhat longish because
355 * it avoids unnecessary writes.
356 */
357
358static struct blame_entry *blame_merge(struct blame_entry *list1,
359 struct blame_entry *list2)
360{
361 struct blame_entry *p1 = list1, *p2 = list2,
362 **tail = &list1;
363
364 if (!p1)
365 return p2;
366 if (!p2)
367 return p1;
368
369 if (p1->s_lno <= p2->s_lno) {
370 do {
371 tail = &p1->next;
372 if ((p1 = *tail) == NULL) {
373 *tail = p2;
374 return list1;
375 }
376 } while (p1->s_lno <= p2->s_lno);
377 }
378 for (;;) {
379 *tail = p2;
380 do {
381 tail = &p2->next;
382 if ((p2 = *tail) == NULL) {
383 *tail = p1;
384 return list1;
385 }
386 } while (p1->s_lno > p2->s_lno);
387 *tail = p1;
388 do {
389 tail = &p1->next;
390 if ((p1 = *tail) == NULL) {
391 *tail = p2;
392 return list1;
393 }
394 } while (p1->s_lno <= p2->s_lno);
395 }
396}
397
398static void *get_next_blame(const void *p)
399{
400 return ((struct blame_entry *)p)->next;
401}
402
403static void set_next_blame(void *p1, void *p2)
404{
405 ((struct blame_entry *)p1)->next = p2;
406}
407
408/*
409 * Final image line numbers are all different, so we don't need a
410 * three-way comparison here.
411 */
412
413static int compare_blame_final(const void *p1, const void *p2)
414{
415 return ((struct blame_entry *)p1)->lno > ((struct blame_entry *)p2)->lno
416 ? 1 : -1;
417}
418
419static int compare_blame_suspect(const void *p1, const void *p2)
420{
421 const struct blame_entry *s1 = p1, *s2 = p2;
422 /*
423 * to allow for collating suspects, we sort according to the
424 * respective pointer value as the primary sorting criterion.
425 * The actual relation is pretty unimportant as long as it
426 * establishes a total order. Comparing as integers gives us
427 * that.
428 */
429 if (s1->suspect != s2->suspect)
430 return (intptr_t)s1->suspect > (intptr_t)s2->suspect ? 1 : -1;
431 if (s1->s_lno == s2->s_lno)
432 return 0;
433 return s1->s_lno > s2->s_lno ? 1 : -1;
434}
435
436void blame_sort_final(struct blame_scoreboard *sb)
437{
438 sb->ent = llist_mergesort(sb->ent, get_next_blame, set_next_blame,
439 compare_blame_final);
440}
441
09002f1b
JS
442static int compare_commits_by_reverse_commit_date(const void *a,
443 const void *b,
444 void *c)
445{
446 return -compare_commits_by_commit_date(a, b, c);
447}
448
b543bb1c
JS
449/*
450 * For debugging -- origin is refcounted, and this asserts that
451 * we do not underflow.
452 */
453static void sanity_check_refcnt(struct blame_scoreboard *sb)
454{
455 int baa = 0;
456 struct blame_entry *ent;
457
458 for (ent = sb->ent; ent; ent = ent->next) {
459 /* Nobody should have zero or negative refcnt */
460 if (ent->suspect->refcnt <= 0) {
461 fprintf(stderr, "%s in %s has negative refcnt %d\n",
462 ent->suspect->path,
463 oid_to_hex(&ent->suspect->commit->object.oid),
464 ent->suspect->refcnt);
465 baa = 1;
466 }
467 }
468 if (baa)
469 sb->on_sanity_fail(sb, baa);
470}
471
472/*
473 * If two blame entries that are next to each other came from
474 * contiguous lines in the same origin (i.e. <commit, path> pair),
475 * merge them together.
476 */
477void blame_coalesce(struct blame_scoreboard *sb)
478{
479 struct blame_entry *ent, *next;
480
481 for (ent = sb->ent; ent && (next = ent->next); ent = next) {
482 if (ent->suspect == next->suspect &&
483 ent->s_lno + ent->num_lines == next->s_lno) {
484 ent->num_lines += next->num_lines;
485 ent->next = next->next;
486 blame_origin_decref(next->suspect);
487 free(next);
488 ent->score = 0;
489 next = ent; /* again */
490 }
491 }
492
493 if (sb->debug) /* sanity */
494 sanity_check_refcnt(sb);
495}
496
497/*
498 * Merge the given sorted list of blames into a preexisting origin.
499 * If there were no previous blames to that commit, it is entered into
500 * the commit priority queue of the score board.
501 */
502
503static void queue_blames(struct blame_scoreboard *sb, struct blame_origin *porigin,
504 struct blame_entry *sorted)
505{
506 if (porigin->suspects)
507 porigin->suspects = blame_merge(porigin->suspects, sorted);
508 else {
509 struct blame_origin *o;
4e0df4e6 510 for (o = get_blame_suspects(porigin->commit); o; o = o->next) {
b543bb1c
JS
511 if (o->suspects) {
512 porigin->suspects = sorted;
513 return;
514 }
515 }
516 porigin->suspects = sorted;
517 prio_queue_put(&sb->commits, porigin->commit);
518 }
519}
520
09002f1b
JS
521/*
522 * Fill the blob_sha1 field of an origin if it hasn't, so that later
523 * call to fill_origin_blob() can use it to locate the data. blob_sha1
524 * for an origin is also used to pass the blame for the entire file to
525 * the parent to detect the case where a child's blob is identical to
526 * that of its parent's.
527 *
528 * This also fills origin->mode for corresponding tree path.
529 */
a470beea 530static int fill_blob_sha1_and_mode(struct repository *r,
ecbbc0a5 531 struct blame_origin *origin)
09002f1b
JS
532{
533 if (!is_null_oid(&origin->blob_oid))
534 return 0;
916bc35b 535 if (get_tree_entry(&origin->commit->object.oid, origin->path, &origin->blob_oid, &origin->mode))
09002f1b 536 goto error_out;
a470beea 537 if (oid_object_info(r, &origin->blob_oid, NULL) != OBJ_BLOB)
09002f1b
JS
538 goto error_out;
539 return 0;
540 error_out:
541 oidclr(&origin->blob_oid);
542 origin->mode = S_IFINVALID;
543 return -1;
544}
545
b543bb1c
JS
546/*
547 * We have an origin -- check if the same path exists in the
548 * parent and return an origin structure to represent it.
549 */
e6757652
NTND
550static struct blame_origin *find_origin(struct repository *r,
551 struct commit *parent,
552 struct blame_origin *origin)
b543bb1c
JS
553{
554 struct blame_origin *porigin;
555 struct diff_options diff_opts;
556 const char *paths[2];
557
558 /* First check any existing origins */
4e0df4e6 559 for (porigin = get_blame_suspects(parent); porigin; porigin = porigin->next)
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JS
560 if (!strcmp(porigin->path, origin->path)) {
561 /*
562 * The same path between origin and its parent
563 * without renaming -- the most common case.
564 */
565 return blame_origin_incref (porigin);
566 }
567
568 /* See if the origin->path is different between parent
569 * and origin first. Most of the time they are the
570 * same and diff-tree is fairly efficient about this.
571 */
e6757652 572 repo_diff_setup(r, &diff_opts);
0d1e0e78 573 diff_opts.flags.recursive = 1;
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JS
574 diff_opts.detect_rename = 0;
575 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
576 paths[0] = origin->path;
577 paths[1] = NULL;
578
579 parse_pathspec(&diff_opts.pathspec,
580 PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
581 PATHSPEC_LITERAL_PATH, "", paths);
582 diff_setup_done(&diff_opts);
583
584 if (is_null_oid(&origin->commit->object.oid))
2e27bd77 585 do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
b543bb1c 586 else
2e27bd77
DS
587 diff_tree_oid(get_commit_tree_oid(parent),
588 get_commit_tree_oid(origin->commit),
a6f38c10 589 "", &diff_opts);
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JS
590 diffcore_std(&diff_opts);
591
592 if (!diff_queued_diff.nr) {
593 /* The path is the same as parent */
594 porigin = get_origin(parent, origin->path);
595 oidcpy(&porigin->blob_oid, &origin->blob_oid);
596 porigin->mode = origin->mode;
597 } else {
598 /*
599 * Since origin->path is a pathspec, if the parent
600 * commit had it as a directory, we will see a whole
601 * bunch of deletion of files in the directory that we
602 * do not care about.
603 */
604 int i;
605 struct diff_filepair *p = NULL;
606 for (i = 0; i < diff_queued_diff.nr; i++) {
607 const char *name;
608 p = diff_queued_diff.queue[i];
609 name = p->one->path ? p->one->path : p->two->path;
610 if (!strcmp(name, origin->path))
611 break;
612 }
613 if (!p)
614 die("internal error in blame::find_origin");
615 switch (p->status) {
616 default:
617 die("internal error in blame::find_origin (%c)",
618 p->status);
619 case 'M':
620 porigin = get_origin(parent, origin->path);
621 oidcpy(&porigin->blob_oid, &p->one->oid);
622 porigin->mode = p->one->mode;
623 break;
624 case 'A':
625 case 'T':
626 /* Did not exist in parent, or type changed */
627 break;
628 }
629 }
630 diff_flush(&diff_opts);
631 clear_pathspec(&diff_opts.pathspec);
632 return porigin;
633}
634
635/*
636 * We have an origin -- find the path that corresponds to it in its
637 * parent and return an origin structure to represent it.
638 */
e6757652
NTND
639static struct blame_origin *find_rename(struct repository *r,
640 struct commit *parent,
641 struct blame_origin *origin)
b543bb1c
JS
642{
643 struct blame_origin *porigin = NULL;
644 struct diff_options diff_opts;
645 int i;
646
e6757652 647 repo_diff_setup(r, &diff_opts);
0d1e0e78 648 diff_opts.flags.recursive = 1;
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649 diff_opts.detect_rename = DIFF_DETECT_RENAME;
650 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
651 diff_opts.single_follow = origin->path;
652 diff_setup_done(&diff_opts);
653
654 if (is_null_oid(&origin->commit->object.oid))
2e27bd77 655 do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
b543bb1c 656 else
2e27bd77
DS
657 diff_tree_oid(get_commit_tree_oid(parent),
658 get_commit_tree_oid(origin->commit),
a6f38c10 659 "", &diff_opts);
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660 diffcore_std(&diff_opts);
661
662 for (i = 0; i < diff_queued_diff.nr; i++) {
663 struct diff_filepair *p = diff_queued_diff.queue[i];
664 if ((p->status == 'R' || p->status == 'C') &&
665 !strcmp(p->two->path, origin->path)) {
666 porigin = get_origin(parent, p->one->path);
667 oidcpy(&porigin->blob_oid, &p->one->oid);
668 porigin->mode = p->one->mode;
669 break;
670 }
671 }
672 diff_flush(&diff_opts);
673 clear_pathspec(&diff_opts.pathspec);
674 return porigin;
675}
676
677/*
678 * Append a new blame entry to a given output queue.
679 */
680static void add_blame_entry(struct blame_entry ***queue,
681 const struct blame_entry *src)
682{
683 struct blame_entry *e = xmalloc(sizeof(*e));
684 memcpy(e, src, sizeof(*e));
685 blame_origin_incref(e->suspect);
686
687 e->next = **queue;
688 **queue = e;
689 *queue = &e->next;
690}
691
692/*
693 * src typically is on-stack; we want to copy the information in it to
694 * a malloced blame_entry that gets added to the given queue. The
695 * origin of dst loses a refcnt.
696 */
697static void dup_entry(struct blame_entry ***queue,
698 struct blame_entry *dst, struct blame_entry *src)
699{
700 blame_origin_incref(src->suspect);
701 blame_origin_decref(dst->suspect);
702 memcpy(dst, src, sizeof(*src));
703 dst->next = **queue;
704 **queue = dst;
705 *queue = &dst->next;
706}
707
708const char *blame_nth_line(struct blame_scoreboard *sb, long lno)
709{
710 return sb->final_buf + sb->lineno[lno];
711}
712
713/*
714 * It is known that lines between tlno to same came from parent, and e
715 * has an overlap with that range. it also is known that parent's
716 * line plno corresponds to e's line tlno.
717 *
718 * <---- e ----->
719 * <------>
720 * <------------>
721 * <------------>
722 * <------------------>
723 *
724 * Split e into potentially three parts; before this chunk, the chunk
725 * to be blamed for the parent, and after that portion.
726 */
727static void split_overlap(struct blame_entry *split,
728 struct blame_entry *e,
729 int tlno, int plno, int same,
730 struct blame_origin *parent)
731{
732 int chunk_end_lno;
733 memset(split, 0, sizeof(struct blame_entry [3]));
734
735 if (e->s_lno < tlno) {
736 /* there is a pre-chunk part not blamed on parent */
737 split[0].suspect = blame_origin_incref(e->suspect);
738 split[0].lno = e->lno;
739 split[0].s_lno = e->s_lno;
740 split[0].num_lines = tlno - e->s_lno;
741 split[1].lno = e->lno + tlno - e->s_lno;
742 split[1].s_lno = plno;
743 }
744 else {
745 split[1].lno = e->lno;
746 split[1].s_lno = plno + (e->s_lno - tlno);
747 }
748
749 if (same < e->s_lno + e->num_lines) {
750 /* there is a post-chunk part not blamed on parent */
751 split[2].suspect = blame_origin_incref(e->suspect);
752 split[2].lno = e->lno + (same - e->s_lno);
753 split[2].s_lno = e->s_lno + (same - e->s_lno);
754 split[2].num_lines = e->s_lno + e->num_lines - same;
755 chunk_end_lno = split[2].lno;
756 }
757 else
758 chunk_end_lno = e->lno + e->num_lines;
759 split[1].num_lines = chunk_end_lno - split[1].lno;
760
761 /*
762 * if it turns out there is nothing to blame the parent for,
763 * forget about the splitting. !split[1].suspect signals this.
764 */
765 if (split[1].num_lines < 1)
766 return;
767 split[1].suspect = blame_origin_incref(parent);
768}
769
770/*
771 * split_overlap() divided an existing blame e into up to three parts
772 * in split. Any assigned blame is moved to queue to
773 * reflect the split.
774 */
775static void split_blame(struct blame_entry ***blamed,
776 struct blame_entry ***unblamed,
777 struct blame_entry *split,
778 struct blame_entry *e)
779{
780 if (split[0].suspect && split[2].suspect) {
781 /* The first part (reuse storage for the existing entry e) */
782 dup_entry(unblamed, e, &split[0]);
783
784 /* The last part -- me */
785 add_blame_entry(unblamed, &split[2]);
786
787 /* ... and the middle part -- parent */
788 add_blame_entry(blamed, &split[1]);
789 }
790 else if (!split[0].suspect && !split[2].suspect)
791 /*
792 * The parent covers the entire area; reuse storage for
793 * e and replace it with the parent.
794 */
795 dup_entry(blamed, e, &split[1]);
796 else if (split[0].suspect) {
797 /* me and then parent */
798 dup_entry(unblamed, e, &split[0]);
799 add_blame_entry(blamed, &split[1]);
800 }
801 else {
802 /* parent and then me */
803 dup_entry(blamed, e, &split[1]);
804 add_blame_entry(unblamed, &split[2]);
805 }
806}
807
808/*
809 * After splitting the blame, the origins used by the
810 * on-stack blame_entry should lose one refcnt each.
811 */
812static void decref_split(struct blame_entry *split)
813{
814 int i;
815
816 for (i = 0; i < 3; i++)
817 blame_origin_decref(split[i].suspect);
818}
819
820/*
821 * reverse_blame reverses the list given in head, appending tail.
822 * That allows us to build lists in reverse order, then reverse them
823 * afterwards. This can be faster than building the list in proper
824 * order right away. The reason is that building in proper order
825 * requires writing a link in the _previous_ element, while building
826 * in reverse order just requires placing the list head into the
827 * _current_ element.
828 */
829
830static struct blame_entry *reverse_blame(struct blame_entry *head,
831 struct blame_entry *tail)
832{
833 while (head) {
834 struct blame_entry *next = head->next;
835 head->next = tail;
836 tail = head;
837 head = next;
838 }
839 return tail;
840}
841
842/*
843 * Process one hunk from the patch between the current suspect for
844 * blame_entry e and its parent. This first blames any unfinished
845 * entries before the chunk (which is where target and parent start
846 * differing) on the parent, and then splits blame entries at the
847 * start and at the end of the difference region. Since use of -M and
848 * -C options may lead to overlapping/duplicate source line number
849 * ranges, all we can rely on from sorting/merging is the order of the
850 * first suspect line number.
851 */
852static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
853 int tlno, int offset, int same,
854 struct blame_origin *parent)
855{
856 struct blame_entry *e = **srcq;
857 struct blame_entry *samep = NULL, *diffp = NULL;
858
859 while (e && e->s_lno < tlno) {
860 struct blame_entry *next = e->next;
861 /*
862 * current record starts before differing portion. If
863 * it reaches into it, we need to split it up and
864 * examine the second part separately.
865 */
866 if (e->s_lno + e->num_lines > tlno) {
867 /* Move second half to a new record */
868 int len = tlno - e->s_lno;
869 struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
870 n->suspect = e->suspect;
871 n->lno = e->lno + len;
872 n->s_lno = e->s_lno + len;
873 n->num_lines = e->num_lines - len;
874 e->num_lines = len;
875 e->score = 0;
876 /* Push new record to diffp */
877 n->next = diffp;
878 diffp = n;
879 } else
880 blame_origin_decref(e->suspect);
881 /* Pass blame for everything before the differing
882 * chunk to the parent */
883 e->suspect = blame_origin_incref(parent);
884 e->s_lno += offset;
885 e->next = samep;
886 samep = e;
887 e = next;
888 }
889 /*
890 * As we don't know how much of a common stretch after this
891 * diff will occur, the currently blamed parts are all that we
892 * can assign to the parent for now.
893 */
894
895 if (samep) {
896 **dstq = reverse_blame(samep, **dstq);
897 *dstq = &samep->next;
898 }
899 /*
900 * Prepend the split off portions: everything after e starts
901 * after the blameable portion.
902 */
903 e = reverse_blame(diffp, e);
904
905 /*
906 * Now retain records on the target while parts are different
907 * from the parent.
908 */
909 samep = NULL;
910 diffp = NULL;
911 while (e && e->s_lno < same) {
912 struct blame_entry *next = e->next;
913
914 /*
915 * If current record extends into sameness, need to split.
916 */
917 if (e->s_lno + e->num_lines > same) {
918 /*
919 * Move second half to a new record to be
920 * processed by later chunks
921 */
922 int len = same - e->s_lno;
923 struct blame_entry *n = xcalloc(1, sizeof (struct blame_entry));
924 n->suspect = blame_origin_incref(e->suspect);
925 n->lno = e->lno + len;
926 n->s_lno = e->s_lno + len;
927 n->num_lines = e->num_lines - len;
928 e->num_lines = len;
929 e->score = 0;
930 /* Push new record to samep */
931 n->next = samep;
932 samep = n;
933 }
934 e->next = diffp;
935 diffp = e;
936 e = next;
937 }
938 **srcq = reverse_blame(diffp, reverse_blame(samep, e));
939 /* Move across elements that are in the unblamable portion */
940 if (diffp)
941 *srcq = &diffp->next;
942}
943
944struct blame_chunk_cb_data {
945 struct blame_origin *parent;
946 long offset;
947 struct blame_entry **dstq;
948 struct blame_entry **srcq;
949};
950
951/* diff chunks are from parent to target */
952static int blame_chunk_cb(long start_a, long count_a,
953 long start_b, long count_b, void *data)
954{
955 struct blame_chunk_cb_data *d = data;
956 if (start_a - start_b != d->offset)
957 die("internal error in blame::blame_chunk_cb");
958 blame_chunk(&d->dstq, &d->srcq, start_b, start_a - start_b,
959 start_b + count_b, d->parent);
960 d->offset = start_a + count_a - (start_b + count_b);
961 return 0;
962}
963
964/*
965 * We are looking at the origin 'target' and aiming to pass blame
966 * for the lines it is suspected to its parent. Run diff to find
967 * which lines came from parent and pass blame for them.
968 */
969static void pass_blame_to_parent(struct blame_scoreboard *sb,
970 struct blame_origin *target,
971 struct blame_origin *parent)
972{
973 mmfile_t file_p, file_o;
974 struct blame_chunk_cb_data d;
975 struct blame_entry *newdest = NULL;
976
977 if (!target->suspects)
978 return; /* nothing remains for this target */
979
980 d.parent = parent;
981 d.offset = 0;
982 d.dstq = &newdest; d.srcq = &target->suspects;
983
984 fill_origin_blob(&sb->revs->diffopt, parent, &file_p, &sb->num_read_blob);
985 fill_origin_blob(&sb->revs->diffopt, target, &file_o, &sb->num_read_blob);
986 sb->num_get_patch++;
987
988 if (diff_hunks(&file_p, &file_o, blame_chunk_cb, &d, sb->xdl_opts))
989 die("unable to generate diff (%s -> %s)",
990 oid_to_hex(&parent->commit->object.oid),
991 oid_to_hex(&target->commit->object.oid));
992 /* The rest are the same as the parent */
993 blame_chunk(&d.dstq, &d.srcq, INT_MAX, d.offset, INT_MAX, parent);
994 *d.dstq = NULL;
995 queue_blames(sb, parent, newdest);
996
997 return;
998}
999
1000/*
1001 * The lines in blame_entry after splitting blames many times can become
1002 * very small and trivial, and at some point it becomes pointless to
1003 * blame the parents. E.g. "\t\t}\n\t}\n\n" appears everywhere in any
1004 * ordinary C program, and it is not worth to say it was copied from
1005 * totally unrelated file in the parent.
1006 *
1007 * Compute how trivial the lines in the blame_entry are.
1008 */
1009unsigned blame_entry_score(struct blame_scoreboard *sb, struct blame_entry *e)
1010{
1011 unsigned score;
1012 const char *cp, *ep;
1013
1014 if (e->score)
1015 return e->score;
1016
1017 score = 1;
1018 cp = blame_nth_line(sb, e->lno);
1019 ep = blame_nth_line(sb, e->lno + e->num_lines);
1020 while (cp < ep) {
1021 unsigned ch = *((unsigned char *)cp);
1022 if (isalnum(ch))
1023 score++;
1024 cp++;
1025 }
1026 e->score = score;
1027 return score;
1028}
1029
1030/*
abeacb25
BW
1031 * best_so_far[] and potential[] are both a split of an existing blame_entry
1032 * that passes blame to the parent. Maintain best_so_far the best split so
1033 * far, by comparing potential and best_so_far and copying potential into
b543bb1c
JS
1034 * bst_so_far as needed.
1035 */
1036static void copy_split_if_better(struct blame_scoreboard *sb,
1037 struct blame_entry *best_so_far,
abeacb25 1038 struct blame_entry *potential)
b543bb1c
JS
1039{
1040 int i;
1041
abeacb25 1042 if (!potential[1].suspect)
b543bb1c
JS
1043 return;
1044 if (best_so_far[1].suspect) {
abeacb25
BW
1045 if (blame_entry_score(sb, &potential[1]) <
1046 blame_entry_score(sb, &best_so_far[1]))
b543bb1c
JS
1047 return;
1048 }
1049
1050 for (i = 0; i < 3; i++)
abeacb25 1051 blame_origin_incref(potential[i].suspect);
b543bb1c 1052 decref_split(best_so_far);
abeacb25 1053 memcpy(best_so_far, potential, sizeof(struct blame_entry[3]));
b543bb1c
JS
1054}
1055
1056/*
1057 * We are looking at a part of the final image represented by
1058 * ent (tlno and same are offset by ent->s_lno).
1059 * tlno is where we are looking at in the final image.
1060 * up to (but not including) same match preimage.
1061 * plno is where we are looking at in the preimage.
1062 *
1063 * <-------------- final image ---------------------->
1064 * <------ent------>
1065 * ^tlno ^same
1066 * <---------preimage----->
1067 * ^plno
1068 *
1069 * All line numbers are 0-based.
1070 */
1071static void handle_split(struct blame_scoreboard *sb,
1072 struct blame_entry *ent,
1073 int tlno, int plno, int same,
1074 struct blame_origin *parent,
1075 struct blame_entry *split)
1076{
1077 if (ent->num_lines <= tlno)
1078 return;
1079 if (tlno < same) {
abeacb25 1080 struct blame_entry potential[3];
b543bb1c
JS
1081 tlno += ent->s_lno;
1082 same += ent->s_lno;
abeacb25
BW
1083 split_overlap(potential, ent, tlno, plno, same, parent);
1084 copy_split_if_better(sb, split, potential);
1085 decref_split(potential);
b543bb1c
JS
1086 }
1087}
1088
1089struct handle_split_cb_data {
1090 struct blame_scoreboard *sb;
1091 struct blame_entry *ent;
1092 struct blame_origin *parent;
1093 struct blame_entry *split;
1094 long plno;
1095 long tlno;
1096};
1097
1098static int handle_split_cb(long start_a, long count_a,
1099 long start_b, long count_b, void *data)
1100{
1101 struct handle_split_cb_data *d = data;
1102 handle_split(d->sb, d->ent, d->tlno, d->plno, start_b, d->parent,
1103 d->split);
1104 d->plno = start_a + count_a;
1105 d->tlno = start_b + count_b;
1106 return 0;
1107}
1108
1109/*
1110 * Find the lines from parent that are the same as ent so that
1111 * we can pass blames to it. file_p has the blob contents for
1112 * the parent.
1113 */
1114static void find_copy_in_blob(struct blame_scoreboard *sb,
1115 struct blame_entry *ent,
1116 struct blame_origin *parent,
1117 struct blame_entry *split,
1118 mmfile_t *file_p)
1119{
1120 const char *cp;
1121 mmfile_t file_o;
1122 struct handle_split_cb_data d;
1123
1124 memset(&d, 0, sizeof(d));
1125 d.sb = sb; d.ent = ent; d.parent = parent; d.split = split;
1126 /*
1127 * Prepare mmfile that contains only the lines in ent.
1128 */
1129 cp = blame_nth_line(sb, ent->lno);
1130 file_o.ptr = (char *) cp;
1131 file_o.size = blame_nth_line(sb, ent->lno + ent->num_lines) - cp;
1132
1133 /*
1134 * file_o is a part of final image we are annotating.
1135 * file_p partially may match that image.
1136 */
1137 memset(split, 0, sizeof(struct blame_entry [3]));
1138 if (diff_hunks(file_p, &file_o, handle_split_cb, &d, sb->xdl_opts))
1139 die("unable to generate diff (%s)",
1140 oid_to_hex(&parent->commit->object.oid));
1141 /* remainder, if any, all match the preimage */
1142 handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split);
1143}
1144
1145/* Move all blame entries from list *source that have a score smaller
1146 * than score_min to the front of list *small.
1147 * Returns a pointer to the link pointing to the old head of the small list.
1148 */
1149
1150static struct blame_entry **filter_small(struct blame_scoreboard *sb,
1151 struct blame_entry **small,
1152 struct blame_entry **source,
1153 unsigned score_min)
1154{
1155 struct blame_entry *p = *source;
1156 struct blame_entry *oldsmall = *small;
1157 while (p) {
1158 if (blame_entry_score(sb, p) <= score_min) {
1159 *small = p;
1160 small = &p->next;
1161 p = *small;
1162 } else {
1163 *source = p;
1164 source = &p->next;
1165 p = *source;
1166 }
1167 }
1168 *small = oldsmall;
1169 *source = NULL;
1170 return small;
1171}
1172
1173/*
1174 * See if lines currently target is suspected for can be attributed to
1175 * parent.
1176 */
1177static void find_move_in_parent(struct blame_scoreboard *sb,
1178 struct blame_entry ***blamed,
1179 struct blame_entry **toosmall,
1180 struct blame_origin *target,
1181 struct blame_origin *parent)
1182{
1183 struct blame_entry *e, split[3];
1184 struct blame_entry *unblamed = target->suspects;
1185 struct blame_entry *leftover = NULL;
1186 mmfile_t file_p;
1187
1188 if (!unblamed)
1189 return; /* nothing remains for this target */
1190
1191 fill_origin_blob(&sb->revs->diffopt, parent, &file_p, &sb->num_read_blob);
1192 if (!file_p.ptr)
1193 return;
1194
1195 /* At each iteration, unblamed has a NULL-terminated list of
1196 * entries that have not yet been tested for blame. leftover
1197 * contains the reversed list of entries that have been tested
1198 * without being assignable to the parent.
1199 */
1200 do {
1201 struct blame_entry **unblamedtail = &unblamed;
1202 struct blame_entry *next;
1203 for (e = unblamed; e; e = next) {
1204 next = e->next;
1205 find_copy_in_blob(sb, e, parent, split, &file_p);
1206 if (split[1].suspect &&
1207 sb->move_score < blame_entry_score(sb, &split[1])) {
1208 split_blame(blamed, &unblamedtail, split, e);
1209 } else {
1210 e->next = leftover;
1211 leftover = e;
1212 }
1213 decref_split(split);
1214 }
1215 *unblamedtail = NULL;
1216 toosmall = filter_small(sb, toosmall, &unblamed, sb->move_score);
1217 } while (unblamed);
1218 target->suspects = reverse_blame(leftover, NULL);
1219}
1220
1221struct blame_list {
1222 struct blame_entry *ent;
1223 struct blame_entry split[3];
1224};
1225
1226/*
1227 * Count the number of entries the target is suspected for,
1228 * and prepare a list of entry and the best split.
1229 */
1230static struct blame_list *setup_blame_list(struct blame_entry *unblamed,
1231 int *num_ents_p)
1232{
1233 struct blame_entry *e;
1234 int num_ents, i;
1235 struct blame_list *blame_list = NULL;
1236
1237 for (e = unblamed, num_ents = 0; e; e = e->next)
1238 num_ents++;
1239 if (num_ents) {
1240 blame_list = xcalloc(num_ents, sizeof(struct blame_list));
1241 for (e = unblamed, i = 0; e; e = e->next)
1242 blame_list[i++].ent = e;
1243 }
1244 *num_ents_p = num_ents;
1245 return blame_list;
1246}
1247
1248/*
1249 * For lines target is suspected for, see if we can find code movement
1250 * across file boundary from the parent commit. porigin is the path
1251 * in the parent we already tried.
1252 */
1253static void find_copy_in_parent(struct blame_scoreboard *sb,
1254 struct blame_entry ***blamed,
1255 struct blame_entry **toosmall,
1256 struct blame_origin *target,
1257 struct commit *parent,
1258 struct blame_origin *porigin,
1259 int opt)
1260{
1261 struct diff_options diff_opts;
1262 int i, j;
1263 struct blame_list *blame_list;
1264 int num_ents;
1265 struct blame_entry *unblamed = target->suspects;
1266 struct blame_entry *leftover = NULL;
1267
1268 if (!unblamed)
1269 return; /* nothing remains for this target */
1270
e6757652 1271 repo_diff_setup(sb->repo, &diff_opts);
0d1e0e78 1272 diff_opts.flags.recursive = 1;
b543bb1c
JS
1273 diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1274
1275 diff_setup_done(&diff_opts);
1276
1277 /* Try "find copies harder" on new path if requested;
1278 * we do not want to use diffcore_rename() actually to
1279 * match things up; find_copies_harder is set only to
a6f38c10 1280 * force diff_tree_oid() to feed all filepairs to diff_queue,
b543bb1c
JS
1281 * and this code needs to be after diff_setup_done(), which
1282 * usually makes find-copies-harder imply copy detection.
1283 */
1284 if ((opt & PICKAXE_BLAME_COPY_HARDEST)
1285 || ((opt & PICKAXE_BLAME_COPY_HARDER)
1286 && (!porigin || strcmp(target->path, porigin->path))))
0d1e0e78 1287 diff_opts.flags.find_copies_harder = 1;
b543bb1c
JS
1288
1289 if (is_null_oid(&target->commit->object.oid))
2e27bd77 1290 do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
b543bb1c 1291 else
2e27bd77
DS
1292 diff_tree_oid(get_commit_tree_oid(parent),
1293 get_commit_tree_oid(target->commit),
a6f38c10 1294 "", &diff_opts);
b543bb1c 1295
0d1e0e78 1296 if (!diff_opts.flags.find_copies_harder)
b543bb1c
JS
1297 diffcore_std(&diff_opts);
1298
1299 do {
1300 struct blame_entry **unblamedtail = &unblamed;
1301 blame_list = setup_blame_list(unblamed, &num_ents);
1302
1303 for (i = 0; i < diff_queued_diff.nr; i++) {
1304 struct diff_filepair *p = diff_queued_diff.queue[i];
1305 struct blame_origin *norigin;
1306 mmfile_t file_p;
abeacb25 1307 struct blame_entry potential[3];
b543bb1c
JS
1308
1309 if (!DIFF_FILE_VALID(p->one))
1310 continue; /* does not exist in parent */
1311 if (S_ISGITLINK(p->one->mode))
1312 continue; /* ignore git links */
1313 if (porigin && !strcmp(p->one->path, porigin->path))
1314 /* find_move already dealt with this path */
1315 continue;
1316
1317 norigin = get_origin(parent, p->one->path);
1318 oidcpy(&norigin->blob_oid, &p->one->oid);
1319 norigin->mode = p->one->mode;
1320 fill_origin_blob(&sb->revs->diffopt, norigin, &file_p, &sb->num_read_blob);
1321 if (!file_p.ptr)
1322 continue;
1323
1324 for (j = 0; j < num_ents; j++) {
1325 find_copy_in_blob(sb, blame_list[j].ent,
abeacb25 1326 norigin, potential, &file_p);
b543bb1c 1327 copy_split_if_better(sb, blame_list[j].split,
abeacb25
BW
1328 potential);
1329 decref_split(potential);
b543bb1c
JS
1330 }
1331 blame_origin_decref(norigin);
1332 }
1333
1334 for (j = 0; j < num_ents; j++) {
1335 struct blame_entry *split = blame_list[j].split;
1336 if (split[1].suspect &&
1337 sb->copy_score < blame_entry_score(sb, &split[1])) {
1338 split_blame(blamed, &unblamedtail, split,
1339 blame_list[j].ent);
1340 } else {
1341 blame_list[j].ent->next = leftover;
1342 leftover = blame_list[j].ent;
1343 }
1344 decref_split(split);
1345 }
1346 free(blame_list);
1347 *unblamedtail = NULL;
1348 toosmall = filter_small(sb, toosmall, &unblamed, sb->copy_score);
1349 } while (unblamed);
1350 target->suspects = reverse_blame(leftover, NULL);
1351 diff_flush(&diff_opts);
1352 clear_pathspec(&diff_opts.pathspec);
1353}
1354
1355/*
1356 * The blobs of origin and porigin exactly match, so everything
1357 * origin is suspected for can be blamed on the parent.
1358 */
1359static void pass_whole_blame(struct blame_scoreboard *sb,
1360 struct blame_origin *origin, struct blame_origin *porigin)
1361{
1362 struct blame_entry *e, *suspects;
1363
1364 if (!porigin->file.ptr && origin->file.ptr) {
1365 /* Steal its file */
1366 porigin->file = origin->file;
1367 origin->file.ptr = NULL;
1368 }
1369 suspects = origin->suspects;
1370 origin->suspects = NULL;
1371 for (e = suspects; e; e = e->next) {
1372 blame_origin_incref(porigin);
1373 blame_origin_decref(e->suspect);
1374 e->suspect = porigin;
1375 }
1376 queue_blames(sb, porigin, suspects);
1377}
1378
1379/*
1380 * We pass blame from the current commit to its parents. We keep saying
1381 * "parent" (and "porigin"), but what we mean is to find scapegoat to
1382 * exonerate ourselves.
1383 */
1384static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit,
1385 int reverse)
1386{
1387 if (!reverse) {
1388 if (revs->first_parent_only &&
1389 commit->parents &&
1390 commit->parents->next) {
1391 free_commit_list(commit->parents->next);
1392 commit->parents->next = NULL;
1393 }
1394 return commit->parents;
1395 }
1396 return lookup_decoration(&revs->children, &commit->object);
1397}
1398
1399static int num_scapegoats(struct rev_info *revs, struct commit *commit, int reverse)
1400{
1401 struct commit_list *l = first_scapegoat(revs, commit, reverse);
1402 return commit_list_count(l);
1403}
1404
1405/* Distribute collected unsorted blames to the respected sorted lists
1406 * in the various origins.
1407 */
1408static void distribute_blame(struct blame_scoreboard *sb, struct blame_entry *blamed)
1409{
1410 blamed = llist_mergesort(blamed, get_next_blame, set_next_blame,
1411 compare_blame_suspect);
1412 while (blamed)
1413 {
1414 struct blame_origin *porigin = blamed->suspect;
1415 struct blame_entry *suspects = NULL;
1416 do {
1417 struct blame_entry *next = blamed->next;
1418 blamed->next = suspects;
1419 suspects = blamed;
1420 blamed = next;
1421 } while (blamed && blamed->suspect == porigin);
1422 suspects = reverse_blame(suspects, NULL);
1423 queue_blames(sb, porigin, suspects);
1424 }
1425}
1426
1427#define MAXSG 16
1428
1429static void pass_blame(struct blame_scoreboard *sb, struct blame_origin *origin, int opt)
1430{
1431 struct rev_info *revs = sb->revs;
1432 int i, pass, num_sg;
1433 struct commit *commit = origin->commit;
1434 struct commit_list *sg;
1435 struct blame_origin *sg_buf[MAXSG];
1436 struct blame_origin *porigin, **sg_origin = sg_buf;
1437 struct blame_entry *toosmall = NULL;
1438 struct blame_entry *blames, **blametail = &blames;
1439
1440 num_sg = num_scapegoats(revs, commit, sb->reverse);
1441 if (!num_sg)
1442 goto finish;
1443 else if (num_sg < ARRAY_SIZE(sg_buf))
1444 memset(sg_buf, 0, sizeof(sg_buf));
1445 else
1446 sg_origin = xcalloc(num_sg, sizeof(*sg_origin));
1447
1448 /*
1449 * The first pass looks for unrenamed path to optimize for
1450 * common cases, then we look for renames in the second pass.
1451 */
1452 for (pass = 0; pass < 2 - sb->no_whole_file_rename; pass++) {
e6757652 1453 struct blame_origin *(*find)(struct repository *, struct commit *, struct blame_origin *);
b543bb1c
JS
1454 find = pass ? find_rename : find_origin;
1455
1456 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1457 i < num_sg && sg;
1458 sg = sg->next, i++) {
1459 struct commit *p = sg->item;
1460 int j, same;
1461
1462 if (sg_origin[i])
1463 continue;
1464 if (parse_commit(p))
1465 continue;
e6757652 1466 porigin = find(sb->repo, p, origin);
b543bb1c
JS
1467 if (!porigin)
1468 continue;
4a7e27e9 1469 if (oideq(&porigin->blob_oid, &origin->blob_oid)) {
b543bb1c
JS
1470 pass_whole_blame(sb, origin, porigin);
1471 blame_origin_decref(porigin);
1472 goto finish;
1473 }
1474 for (j = same = 0; j < i; j++)
1475 if (sg_origin[j] &&
4a7e27e9 1476 oideq(&sg_origin[j]->blob_oid, &porigin->blob_oid)) {
b543bb1c
JS
1477 same = 1;
1478 break;
1479 }
1480 if (!same)
1481 sg_origin[i] = porigin;
1482 else
1483 blame_origin_decref(porigin);
1484 }
1485 }
1486
1487 sb->num_commits++;
1488 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1489 i < num_sg && sg;
1490 sg = sg->next, i++) {
1491 struct blame_origin *porigin = sg_origin[i];
1492 if (!porigin)
1493 continue;
1494 if (!origin->previous) {
1495 blame_origin_incref(porigin);
1496 origin->previous = porigin;
1497 }
1498 pass_blame_to_parent(sb, origin, porigin);
1499 if (!origin->suspects)
1500 goto finish;
1501 }
1502
1503 /*
1504 * Optionally find moves in parents' files.
1505 */
1506 if (opt & PICKAXE_BLAME_MOVE) {
1507 filter_small(sb, &toosmall, &origin->suspects, sb->move_score);
1508 if (origin->suspects) {
1509 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1510 i < num_sg && sg;
1511 sg = sg->next, i++) {
1512 struct blame_origin *porigin = sg_origin[i];
1513 if (!porigin)
1514 continue;
1515 find_move_in_parent(sb, &blametail, &toosmall, origin, porigin);
1516 if (!origin->suspects)
1517 break;
1518 }
1519 }
1520 }
1521
1522 /*
1523 * Optionally find copies from parents' files.
1524 */
1525 if (opt & PICKAXE_BLAME_COPY) {
1526 if (sb->copy_score > sb->move_score)
1527 filter_small(sb, &toosmall, &origin->suspects, sb->copy_score);
1528 else if (sb->copy_score < sb->move_score) {
1529 origin->suspects = blame_merge(origin->suspects, toosmall);
1530 toosmall = NULL;
1531 filter_small(sb, &toosmall, &origin->suspects, sb->copy_score);
1532 }
1533 if (!origin->suspects)
1534 goto finish;
1535
1536 for (i = 0, sg = first_scapegoat(revs, commit, sb->reverse);
1537 i < num_sg && sg;
1538 sg = sg->next, i++) {
1539 struct blame_origin *porigin = sg_origin[i];
1540 find_copy_in_parent(sb, &blametail, &toosmall,
1541 origin, sg->item, porigin, opt);
1542 if (!origin->suspects)
1543 goto finish;
1544 }
1545 }
1546
1547finish:
1548 *blametail = NULL;
1549 distribute_blame(sb, blames);
1550 /*
1551 * prepend toosmall to origin->suspects
1552 *
1553 * There is no point in sorting: this ends up on a big
1554 * unsorted list in the caller anyway.
1555 */
1556 if (toosmall) {
1557 struct blame_entry **tail = &toosmall;
1558 while (*tail)
1559 tail = &(*tail)->next;
1560 *tail = origin->suspects;
1561 origin->suspects = toosmall;
1562 }
1563 for (i = 0; i < num_sg; i++) {
1564 if (sg_origin[i]) {
f8920149
DK
1565 if (!sg_origin[i]->suspects)
1566 drop_origin_blob(sg_origin[i]);
b543bb1c
JS
1567 blame_origin_decref(sg_origin[i]);
1568 }
1569 }
1570 drop_origin_blob(origin);
1571 if (sg_buf != sg_origin)
1572 free(sg_origin);
1573}
1574
1575/*
1576 * The main loop -- while we have blobs with lines whose true origin
1577 * is still unknown, pick one blob, and allow its lines to pass blames
1578 * to its parents. */
1579void assign_blame(struct blame_scoreboard *sb, int opt)
1580{
1581 struct rev_info *revs = sb->revs;
1582 struct commit *commit = prio_queue_get(&sb->commits);
1583
1584 while (commit) {
1585 struct blame_entry *ent;
4e0df4e6 1586 struct blame_origin *suspect = get_blame_suspects(commit);
b543bb1c
JS
1587
1588 /* find one suspect to break down */
1589 while (suspect && !suspect->suspects)
1590 suspect = suspect->next;
1591
1592 if (!suspect) {
1593 commit = prio_queue_get(&sb->commits);
1594 continue;
1595 }
1596
1597 assert(commit == suspect->commit);
1598
1599 /*
1600 * We will use this suspect later in the loop,
1601 * so hold onto it in the meantime.
1602 */
1603 blame_origin_incref(suspect);
1604 parse_commit(commit);
1605 if (sb->reverse ||
1606 (!(commit->object.flags & UNINTERESTING) &&
1607 !(revs->max_age != -1 && commit->date < revs->max_age)))
1608 pass_blame(sb, suspect, opt);
1609 else {
1610 commit->object.flags |= UNINTERESTING;
1611 if (commit->object.parsed)
1612 mark_parents_uninteresting(commit);
1613 }
1614 /* treat root commit as boundary */
1615 if (!commit->parents && !sb->show_root)
1616 commit->object.flags |= UNINTERESTING;
1617
1618 /* Take responsibility for the remaining entries */
1619 ent = suspect->suspects;
1620 if (ent) {
1621 suspect->guilty = 1;
1622 for (;;) {
1623 struct blame_entry *next = ent->next;
1624 if (sb->found_guilty_entry)
1625 sb->found_guilty_entry(ent, sb->found_guilty_entry_data);
1626 if (next) {
1627 ent = next;
1628 continue;
1629 }
1630 ent->next = sb->ent;
1631 sb->ent = suspect->suspects;
1632 suspect->suspects = NULL;
1633 break;
1634 }
1635 }
1636 blame_origin_decref(suspect);
1637
1638 if (sb->debug) /* sanity */
1639 sanity_check_refcnt(sb);
1640 }
1641}
09002f1b
JS
1642
1643static const char *get_next_line(const char *start, const char *end)
1644{
1645 const char *nl = memchr(start, '\n', end - start);
1646 return nl ? nl + 1 : end;
1647}
1648
1649/*
1650 * To allow quick access to the contents of nth line in the
1651 * final image, prepare an index in the scoreboard.
1652 */
1653static int prepare_lines(struct blame_scoreboard *sb)
1654{
1655 const char *buf = sb->final_buf;
1656 unsigned long len = sb->final_buf_size;
1657 const char *end = buf + len;
1658 const char *p;
1659 int *lineno;
1660 int num = 0;
1661
1662 for (p = buf; p < end; p = get_next_line(p, end))
1663 num++;
1664
1665 ALLOC_ARRAY(sb->lineno, num + 1);
1666 lineno = sb->lineno;
1667
1668 for (p = buf; p < end; p = get_next_line(p, end))
1669 *lineno++ = p - buf;
1670
1671 *lineno = len;
1672
1673 sb->num_lines = num;
1674 return sb->num_lines;
1675}
1676
1677static struct commit *find_single_final(struct rev_info *revs,
1678 const char **name_p)
1679{
1680 int i;
1681 struct commit *found = NULL;
1682 const char *name = NULL;
1683
1684 for (i = 0; i < revs->pending.nr; i++) {
1685 struct object *obj = revs->pending.objects[i].item;
1686 if (obj->flags & UNINTERESTING)
1687 continue;
fb998eae 1688 obj = deref_tag(revs->repo, obj, NULL, 0);
09002f1b
JS
1689 if (obj->type != OBJ_COMMIT)
1690 die("Non commit %s?", revs->pending.objects[i].name);
1691 if (found)
1692 die("More than one commit to dig from %s and %s?",
1693 revs->pending.objects[i].name, name);
1694 found = (struct commit *)obj;
1695 name = revs->pending.objects[i].name;
1696 }
1697 if (name_p)
9e7d8a9b 1698 *name_p = xstrdup_or_null(name);
09002f1b
JS
1699 return found;
1700}
1701
1702static struct commit *dwim_reverse_initial(struct rev_info *revs,
1703 const char **name_p)
1704{
1705 /*
1706 * DWIM "git blame --reverse ONE -- PATH" as
1707 * "git blame --reverse ONE..HEAD -- PATH" but only do so
1708 * when it makes sense.
1709 */
1710 struct object *obj;
1711 struct commit *head_commit;
583c6a22 1712 struct object_id head_oid;
09002f1b
JS
1713
1714 if (revs->pending.nr != 1)
1715 return NULL;
1716
1717 /* Is that sole rev a committish? */
1718 obj = revs->pending.objects[0].item;
fb998eae 1719 obj = deref_tag(revs->repo, obj, NULL, 0);
09002f1b
JS
1720 if (obj->type != OBJ_COMMIT)
1721 return NULL;
1722
1723 /* Do we have HEAD? */
49e61479 1724 if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
09002f1b 1725 return NULL;
fb998eae 1726 head_commit = lookup_commit_reference_gently(revs->repo,
21e1ee8f 1727 &head_oid, 1);
09002f1b
JS
1728 if (!head_commit)
1729 return NULL;
1730
1731 /* Turn "ONE" into "ONE..HEAD" then */
1732 obj->flags |= UNINTERESTING;
1733 add_pending_object(revs, &head_commit->object, "HEAD");
1734
1735 if (name_p)
1736 *name_p = revs->pending.objects[0].name;
1737 return (struct commit *)obj;
1738}
1739
1740static struct commit *find_single_initial(struct rev_info *revs,
1741 const char **name_p)
1742{
1743 int i;
1744 struct commit *found = NULL;
1745 const char *name = NULL;
1746
1747 /*
1748 * There must be one and only one negative commit, and it must be
1749 * the boundary.
1750 */
1751 for (i = 0; i < revs->pending.nr; i++) {
1752 struct object *obj = revs->pending.objects[i].item;
1753 if (!(obj->flags & UNINTERESTING))
1754 continue;
fb998eae 1755 obj = deref_tag(revs->repo, obj, NULL, 0);
09002f1b
JS
1756 if (obj->type != OBJ_COMMIT)
1757 die("Non commit %s?", revs->pending.objects[i].name);
1758 if (found)
1759 die("More than one commit to dig up from, %s and %s?",
1760 revs->pending.objects[i].name, name);
1761 found = (struct commit *) obj;
1762 name = revs->pending.objects[i].name;
1763 }
1764
1765 if (!name)
1766 found = dwim_reverse_initial(revs, &name);
1767 if (!name)
1768 die("No commit to dig up from?");
1769
1770 if (name_p)
9e7d8a9b 1771 *name_p = xstrdup(name);
09002f1b
JS
1772 return found;
1773}
1774
1775void init_scoreboard(struct blame_scoreboard *sb)
1776{
1777 memset(sb, 0, sizeof(struct blame_scoreboard));
1778 sb->move_score = BLAME_DEFAULT_MOVE_SCORE;
1779 sb->copy_score = BLAME_DEFAULT_COPY_SCORE;
1780}
1781
ecbbc0a5
NTND
1782void setup_scoreboard(struct blame_scoreboard *sb,
1783 const char *path,
1784 struct blame_origin **orig)
09002f1b
JS
1785{
1786 const char *final_commit_name = NULL;
1787 struct blame_origin *o;
1788 struct commit *final_commit = NULL;
1789 enum object_type type;
1790
4e0df4e6
NTND
1791 init_blame_suspects(&blame_suspects);
1792
09002f1b
JS
1793 if (sb->reverse && sb->contents_from)
1794 die(_("--contents and --reverse do not blend well."));
1795
ecbbc0a5
NTND
1796 if (!sb->repo)
1797 BUG("repo is NULL");
1798
09002f1b
JS
1799 if (!sb->reverse) {
1800 sb->final = find_single_final(sb->revs, &final_commit_name);
1801 sb->commits.compare = compare_commits_by_commit_date;
1802 } else {
1803 sb->final = find_single_initial(sb->revs, &final_commit_name);
1804 sb->commits.compare = compare_commits_by_reverse_commit_date;
1805 }
1806
1807 if (sb->final && sb->contents_from)
1808 die(_("cannot use --contents with final commit object name"));
1809
1810 if (sb->reverse && sb->revs->first_parent_only)
1811 sb->revs->children.name = NULL;
1812
1813 if (!sb->final) {
1814 /*
1815 * "--not A B -- path" without anything positive;
1816 * do not default to HEAD, but use the working tree
1817 * or "--contents".
1818 */
1819 setup_work_tree();
ecbbc0a5
NTND
1820 sb->final = fake_working_tree_commit(sb->repo,
1821 &sb->revs->diffopt,
09002f1b
JS
1822 path, sb->contents_from);
1823 add_pending_object(sb->revs, &(sb->final->object), ":");
1824 }
1825
1826 if (sb->reverse && sb->revs->first_parent_only) {
1827 final_commit = find_single_final(sb->revs, NULL);
1828 if (!final_commit)
1829 die(_("--reverse and --first-parent together require specified latest commit"));
1830 }
1831
1832 /*
1833 * If we have bottom, this will mark the ancestors of the
1834 * bottom commits we would reach while traversing as
1835 * uninteresting.
1836 */
1837 if (prepare_revision_walk(sb->revs))
1838 die(_("revision walk setup failed"));
1839
1840 if (sb->reverse && sb->revs->first_parent_only) {
1841 struct commit *c = final_commit;
1842
1843 sb->revs->children.name = "children";
1844 while (c->parents &&
9001dc2a 1845 !oideq(&c->object.oid, &sb->final->object.oid)) {
09002f1b
JS
1846 struct commit_list *l = xcalloc(1, sizeof(*l));
1847
1848 l->item = c;
1849 if (add_decoration(&sb->revs->children,
1850 &c->parents->item->object, l))
033abf97 1851 BUG("not unique item in first-parent chain");
09002f1b
JS
1852 c = c->parents->item;
1853 }
1854
9001dc2a 1855 if (!oideq(&c->object.oid, &sb->final->object.oid))
09002f1b
JS
1856 die(_("--reverse --first-parent together require range along first-parent chain"));
1857 }
1858
1859 if (is_null_oid(&sb->final->object.oid)) {
4e0df4e6 1860 o = get_blame_suspects(sb->final);
09002f1b
JS
1861 sb->final_buf = xmemdupz(o->file.ptr, o->file.size);
1862 sb->final_buf_size = o->file.size;
1863 }
1864 else {
1865 o = get_origin(sb->final, path);
ecbbc0a5 1866 if (fill_blob_sha1_and_mode(sb->repo, o))
09002f1b
JS
1867 die(_("no such path %s in %s"), path, final_commit_name);
1868
0d1e0e78 1869 if (sb->revs->diffopt.flags.allow_textconv &&
6afaf807 1870 textconv_object(sb->repo, path, o->mode, &o->blob_oid, 1, (char **) &sb->final_buf,
09002f1b
JS
1871 &sb->final_buf_size))
1872 ;
1873 else
b4f5aca4 1874 sb->final_buf = read_object_file(&o->blob_oid, &type,
1875 &sb->final_buf_size);
09002f1b
JS
1876
1877 if (!sb->final_buf)
1878 die(_("cannot read blob %s for path %s"),
1879 oid_to_hex(&o->blob_oid),
1880 path);
1881 }
1882 sb->num_read_blob++;
1883 prepare_lines(sb);
1884
1885 if (orig)
1886 *orig = o;
9e7d8a9b
SG
1887
1888 free((char *)final_commit_name);
09002f1b 1889}
bd481de7
JS
1890
1891
1892
1893struct blame_entry *blame_entry_prepend(struct blame_entry *head,
1894 long start, long end,
1895 struct blame_origin *o)
1896{
1897 struct blame_entry *new_head = xcalloc(1, sizeof(struct blame_entry));
1898 new_head->lno = start;
1899 new_head->num_lines = end - start;
1900 new_head->suspect = o;
1901 new_head->s_lno = start;
1902 new_head->next = head;
1903 blame_origin_incref(o);
1904 return new_head;
1905}