da1ab54027261bfb929af4154d653453b3c0fbad
1#include "cache.h"
2#include "config.h"
3#include "lockfile.h"
4#include "string-list.h"
5#include "rerere.h"
6#include "xdiff-interface.h"
7#include "dir.h"
8#include "resolve-undo.h"
9#include "ll-merge.h"
10#include "attr.h"
11#include "pathspec.h"
12#include "sha1-lookup.h"
13
14#define RESOLVED 0
15#define PUNTED 1
16#define THREE_STAGED 2
17void *RERERE_RESOLVED = &RERERE_RESOLVED;
18
19/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
20static int rerere_enabled = -1;
21
22/* automatically update cleanly resolved paths to the index */
23static int rerere_autoupdate;
24
25static int rerere_dir_nr;
26static int rerere_dir_alloc;
27
28#define RR_HAS_POSTIMAGE 1
29#define RR_HAS_PREIMAGE 2
30static struct rerere_dir {
31 unsigned char sha1[20];
32 int status_alloc, status_nr;
33 unsigned char *status;
34} **rerere_dir;
35
36static void free_rerere_dirs(void)
37{
38 int i;
39 for (i = 0; i < rerere_dir_nr; i++) {
40 free(rerere_dir[i]->status);
41 free(rerere_dir[i]);
42 }
43 FREE_AND_NULL(rerere_dir);
44 rerere_dir_nr = rerere_dir_alloc = 0;
45}
46
47static void free_rerere_id(struct string_list_item *item)
48{
49 free(item->util);
50}
51
52static const char *rerere_id_hex(const struct rerere_id *id)
53{
54 return sha1_to_hex(id->collection->sha1);
55}
56
57static void fit_variant(struct rerere_dir *rr_dir, int variant)
58{
59 variant++;
60 ALLOC_GROW(rr_dir->status, variant, rr_dir->status_alloc);
61 if (rr_dir->status_nr < variant) {
62 memset(rr_dir->status + rr_dir->status_nr,
63 '\0', variant - rr_dir->status_nr);
64 rr_dir->status_nr = variant;
65 }
66}
67
68static void assign_variant(struct rerere_id *id)
69{
70 int variant;
71 struct rerere_dir *rr_dir = id->collection;
72
73 variant = id->variant;
74 if (variant < 0) {
75 for (variant = 0; variant < rr_dir->status_nr; variant++)
76 if (!rr_dir->status[variant])
77 break;
78 }
79 fit_variant(rr_dir, variant);
80 id->variant = variant;
81}
82
83const char *rerere_path(const struct rerere_id *id, const char *file)
84{
85 if (!file)
86 return git_path("rr-cache/%s", rerere_id_hex(id));
87
88 if (id->variant <= 0)
89 return git_path("rr-cache/%s/%s", rerere_id_hex(id), file);
90
91 return git_path("rr-cache/%s/%s.%d",
92 rerere_id_hex(id), file, id->variant);
93}
94
95static int is_rr_file(const char *name, const char *filename, int *variant)
96{
97 const char *suffix;
98 char *ep;
99
100 if (!strcmp(name, filename)) {
101 *variant = 0;
102 return 1;
103 }
104 if (!skip_prefix(name, filename, &suffix) || *suffix != '.')
105 return 0;
106
107 errno = 0;
108 *variant = strtol(suffix + 1, &ep, 10);
109 if (errno || *ep)
110 return 0;
111 return 1;
112}
113
114static void scan_rerere_dir(struct rerere_dir *rr_dir)
115{
116 struct dirent *de;
117 DIR *dir = opendir(git_path("rr-cache/%s", sha1_to_hex(rr_dir->sha1)));
118
119 if (!dir)
120 return;
121 while ((de = readdir(dir)) != NULL) {
122 int variant;
123
124 if (is_rr_file(de->d_name, "postimage", &variant)) {
125 fit_variant(rr_dir, variant);
126 rr_dir->status[variant] |= RR_HAS_POSTIMAGE;
127 } else if (is_rr_file(de->d_name, "preimage", &variant)) {
128 fit_variant(rr_dir, variant);
129 rr_dir->status[variant] |= RR_HAS_PREIMAGE;
130 }
131 }
132 closedir(dir);
133}
134
135static const unsigned char *rerere_dir_sha1(size_t i, void *table)
136{
137 struct rerere_dir **rr_dir = table;
138 return rr_dir[i]->sha1;
139}
140
141static struct rerere_dir *find_rerere_dir(const char *hex)
142{
143 unsigned char sha1[20];
144 struct rerere_dir *rr_dir;
145 int pos;
146
147 if (get_sha1_hex(hex, sha1))
148 return NULL; /* BUG */
149 pos = sha1_pos(sha1, rerere_dir, rerere_dir_nr, rerere_dir_sha1);
150 if (pos < 0) {
151 rr_dir = xmalloc(sizeof(*rr_dir));
152 hashcpy(rr_dir->sha1, sha1);
153 rr_dir->status = NULL;
154 rr_dir->status_nr = 0;
155 rr_dir->status_alloc = 0;
156 pos = -1 - pos;
157
158 /* Make sure the array is big enough ... */
159 ALLOC_GROW(rerere_dir, rerere_dir_nr + 1, rerere_dir_alloc);
160 /* ... and add it in. */
161 rerere_dir_nr++;
162 MOVE_ARRAY(rerere_dir + pos + 1, rerere_dir + pos,
163 rerere_dir_nr - pos - 1);
164 rerere_dir[pos] = rr_dir;
165 scan_rerere_dir(rr_dir);
166 }
167 return rerere_dir[pos];
168}
169
170static int has_rerere_resolution(const struct rerere_id *id)
171{
172 const int both = RR_HAS_POSTIMAGE|RR_HAS_PREIMAGE;
173 int variant = id->variant;
174
175 if (variant < 0)
176 return 0;
177 return ((id->collection->status[variant] & both) == both);
178}
179
180static struct rerere_id *new_rerere_id_hex(char *hex)
181{
182 struct rerere_id *id = xmalloc(sizeof(*id));
183 id->collection = find_rerere_dir(hex);
184 id->variant = -1; /* not known yet */
185 return id;
186}
187
188static struct rerere_id *new_rerere_id(unsigned char *sha1)
189{
190 return new_rerere_id_hex(sha1_to_hex(sha1));
191}
192
193/*
194 * $GIT_DIR/MERGE_RR file is a collection of records, each of which is
195 * "conflict ID", a HT and pathname, terminated with a NUL, and is
196 * used to keep track of the set of paths that "rerere" may need to
197 * work on (i.e. what is left by the previous invocation of "git
198 * rerere" during the current conflict resolution session).
199 */
200static void read_rr(struct string_list *rr)
201{
202 struct strbuf buf = STRBUF_INIT;
203 FILE *in = fopen_or_warn(git_path_merge_rr(), "r");
204
205 if (!in)
206 return;
207 while (!strbuf_getwholeline(&buf, in, '\0')) {
208 char *path;
209 unsigned char sha1[20];
210 struct rerere_id *id;
211 int variant;
212
213 /* There has to be the hash, tab, path and then NUL */
214 if (buf.len < 42 || get_sha1_hex(buf.buf, sha1))
215 die(_("corrupt MERGE_RR"));
216
217 if (buf.buf[40] != '.') {
218 variant = 0;
219 path = buf.buf + 40;
220 } else {
221 errno = 0;
222 variant = strtol(buf.buf + 41, &path, 10);
223 if (errno)
224 die(_("corrupt MERGE_RR"));
225 }
226 if (*(path++) != '\t')
227 die(_("corrupt MERGE_RR"));
228 buf.buf[40] = '\0';
229 id = new_rerere_id_hex(buf.buf);
230 id->variant = variant;
231 string_list_insert(rr, path)->util = id;
232 }
233 strbuf_release(&buf);
234 fclose(in);
235}
236
237static struct lock_file write_lock;
238
239static int write_rr(struct string_list *rr, int out_fd)
240{
241 int i;
242 for (i = 0; i < rr->nr; i++) {
243 struct strbuf buf = STRBUF_INIT;
244 struct rerere_id *id;
245
246 assert(rr->items[i].util != RERERE_RESOLVED);
247
248 id = rr->items[i].util;
249 if (!id)
250 continue;
251 assert(id->variant >= 0);
252 if (0 < id->variant)
253 strbuf_addf(&buf, "%s.%d\t%s%c",
254 rerere_id_hex(id), id->variant,
255 rr->items[i].string, 0);
256 else
257 strbuf_addf(&buf, "%s\t%s%c",
258 rerere_id_hex(id),
259 rr->items[i].string, 0);
260
261 if (write_in_full(out_fd, buf.buf, buf.len) < 0)
262 die(_("unable to write rerere record"));
263
264 strbuf_release(&buf);
265 }
266 if (commit_lock_file(&write_lock) != 0)
267 die(_("unable to write rerere record"));
268 return 0;
269}
270
271/*
272 * "rerere" interacts with conflicted file contents using this I/O
273 * abstraction. It reads a conflicted contents from one place via
274 * "getline()" method, and optionally can write it out after
275 * normalizing the conflicted hunks to the "output". Subclasses of
276 * rerere_io embed this structure at the beginning of their own
277 * rerere_io object.
278 */
279struct rerere_io {
280 int (*getline)(struct strbuf *, struct rerere_io *);
281 FILE *output;
282 int wrerror;
283 /* some more stuff */
284};
285
286static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
287{
288 if (!count || *err)
289 return;
290 if (fwrite(p, count, 1, fp) != 1)
291 *err = errno;
292}
293
294static inline void ferr_puts(const char *s, FILE *fp, int *err)
295{
296 ferr_write(s, strlen(s), fp, err);
297}
298
299static void rerere_io_putstr(const char *str, struct rerere_io *io)
300{
301 if (io->output)
302 ferr_puts(str, io->output, &io->wrerror);
303}
304
305/*
306 * Write a conflict marker to io->output (if defined).
307 */
308static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
309{
310 char buf[64];
311
312 while (size) {
313 if (size <= sizeof(buf) - 2) {
314 memset(buf, ch, size);
315 buf[size] = '\n';
316 buf[size + 1] = '\0';
317 size = 0;
318 } else {
319 int sz = sizeof(buf) - 1;
320
321 /*
322 * Make sure we will not write everything out
323 * in this round by leaving at least 1 byte
324 * for the next round, giving the next round
325 * a chance to add the terminating LF. Yuck.
326 */
327 if (size <= sz)
328 sz -= (sz - size) + 1;
329 memset(buf, ch, sz);
330 buf[sz] = '\0';
331 size -= sz;
332 }
333 rerere_io_putstr(buf, io);
334 }
335}
336
337static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
338{
339 if (io->output)
340 ferr_write(mem, sz, io->output, &io->wrerror);
341}
342
343/*
344 * Subclass of rerere_io that reads from an on-disk file
345 */
346struct rerere_io_file {
347 struct rerere_io io;
348 FILE *input;
349};
350
351/*
352 * ... and its getline() method implementation
353 */
354static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
355{
356 struct rerere_io_file *io = (struct rerere_io_file *)io_;
357 return strbuf_getwholeline(sb, io->input, '\n');
358}
359
360/*
361 * Require the exact number of conflict marker letters, no more, no
362 * less, followed by SP or any whitespace
363 * (including LF).
364 */
365static int is_cmarker(char *buf, int marker_char, int marker_size)
366{
367 int want_sp;
368
369 /*
370 * The beginning of our version and the end of their version
371 * always are labeled like "<<<<< ours" or ">>>>> theirs",
372 * hence we set want_sp for them. Note that the version from
373 * the common ancestor in diff3-style output is not always
374 * labelled (e.g. "||||| common" is often seen but "|||||"
375 * alone is also valid), so we do not set want_sp.
376 */
377 want_sp = (marker_char == '<') || (marker_char == '>');
378
379 while (marker_size--)
380 if (*buf++ != marker_char)
381 return 0;
382 if (want_sp && *buf != ' ')
383 return 0;
384 return isspace(*buf);
385}
386
387/*
388 * Read contents a file with conflicts, normalize the conflicts
389 * by (1) discarding the common ancestor version in diff3-style,
390 * (2) reordering our side and their side so that whichever sorts
391 * alphabetically earlier comes before the other one, while
392 * computing the "conflict ID", which is just an SHA-1 hash of
393 * one side of the conflict, NUL, the other side of the conflict,
394 * and NUL concatenated together.
395 *
396 * Return the number of conflict hunks found.
397 */
398static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
399{
400 git_SHA_CTX ctx;
401 int hunk_no = 0;
402 enum {
403 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL
404 } hunk = RR_CONTEXT;
405 struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
406 struct strbuf buf = STRBUF_INIT;
407
408 if (sha1)
409 git_SHA1_Init(&ctx);
410
411 while (!io->getline(&buf, io)) {
412 if (is_cmarker(buf.buf, '<', marker_size)) {
413 if (hunk != RR_CONTEXT)
414 goto bad;
415 hunk = RR_SIDE_1;
416 } else if (is_cmarker(buf.buf, '|', marker_size)) {
417 if (hunk != RR_SIDE_1)
418 goto bad;
419 hunk = RR_ORIGINAL;
420 } else if (is_cmarker(buf.buf, '=', marker_size)) {
421 if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
422 goto bad;
423 hunk = RR_SIDE_2;
424 } else if (is_cmarker(buf.buf, '>', marker_size)) {
425 if (hunk != RR_SIDE_2)
426 goto bad;
427 if (strbuf_cmp(&one, &two) > 0)
428 strbuf_swap(&one, &two);
429 hunk_no++;
430 hunk = RR_CONTEXT;
431 rerere_io_putconflict('<', marker_size, io);
432 rerere_io_putmem(one.buf, one.len, io);
433 rerere_io_putconflict('=', marker_size, io);
434 rerere_io_putmem(two.buf, two.len, io);
435 rerere_io_putconflict('>', marker_size, io);
436 if (sha1) {
437 git_SHA1_Update(&ctx, one.buf ? one.buf : "",
438 one.len + 1);
439 git_SHA1_Update(&ctx, two.buf ? two.buf : "",
440 two.len + 1);
441 }
442 strbuf_reset(&one);
443 strbuf_reset(&two);
444 } else if (hunk == RR_SIDE_1)
445 strbuf_addbuf(&one, &buf);
446 else if (hunk == RR_ORIGINAL)
447 ; /* discard */
448 else if (hunk == RR_SIDE_2)
449 strbuf_addbuf(&two, &buf);
450 else
451 rerere_io_putstr(buf.buf, io);
452 continue;
453 bad:
454 hunk = 99; /* force error exit */
455 break;
456 }
457 strbuf_release(&one);
458 strbuf_release(&two);
459 strbuf_release(&buf);
460
461 if (sha1)
462 git_SHA1_Final(sha1, &ctx);
463 if (hunk != RR_CONTEXT)
464 return -1;
465 return hunk_no;
466}
467
468/*
469 * Scan the path for conflicts, do the "handle_path()" thing above, and
470 * return the number of conflict hunks found.
471 */
472static int handle_file(const char *path, unsigned char *sha1, const char *output)
473{
474 int hunk_no = 0;
475 struct rerere_io_file io;
476 int marker_size = ll_merge_marker_size(path);
477
478 memset(&io, 0, sizeof(io));
479 io.io.getline = rerere_file_getline;
480 io.input = fopen(path, "r");
481 io.io.wrerror = 0;
482 if (!io.input)
483 return error_errno(_("could not open '%s'"), path);
484
485 if (output) {
486 io.io.output = fopen(output, "w");
487 if (!io.io.output) {
488 error_errno(_("could not write '%s'"), output);
489 fclose(io.input);
490 return -1;
491 }
492 }
493
494 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
495
496 fclose(io.input);
497 if (io.io.wrerror)
498 error(_("there were errors while writing '%s' (%s)"),
499 path, strerror(io.io.wrerror));
500 if (io.io.output && fclose(io.io.output))
501 io.io.wrerror = error_errno(_("failed to flush '%s'"), path);
502
503 if (hunk_no < 0) {
504 if (output)
505 unlink_or_warn(output);
506 return error(_("could not parse conflict hunks in '%s'"), path);
507 }
508 if (io.io.wrerror)
509 return -1;
510 return hunk_no;
511}
512
513/*
514 * Look at a cache entry at "i" and see if it is not conflicting,
515 * conflicting and we are willing to handle, or conflicting and
516 * we are unable to handle, and return the determination in *type.
517 * Return the cache index to be looked at next, by skipping the
518 * stages we have already looked at in this invocation of this
519 * function.
520 */
521static int check_one_conflict(int i, int *type)
522{
523 const struct cache_entry *e = active_cache[i];
524
525 if (!ce_stage(e)) {
526 *type = RESOLVED;
527 return i + 1;
528 }
529
530 *type = PUNTED;
531 while (ce_stage(active_cache[i]) == 1)
532 i++;
533
534 /* Only handle regular files with both stages #2 and #3 */
535 if (i + 1 < active_nr) {
536 const struct cache_entry *e2 = active_cache[i];
537 const struct cache_entry *e3 = active_cache[i + 1];
538 if (ce_stage(e2) == 2 &&
539 ce_stage(e3) == 3 &&
540 ce_same_name(e, e3) &&
541 S_ISREG(e2->ce_mode) &&
542 S_ISREG(e3->ce_mode))
543 *type = THREE_STAGED;
544 }
545
546 /* Skip the entries with the same name */
547 while (i < active_nr && ce_same_name(e, active_cache[i]))
548 i++;
549 return i;
550}
551
552/*
553 * Scan the index and find paths that have conflicts that rerere can
554 * handle, i.e. the ones that has both stages #2 and #3.
555 *
556 * NEEDSWORK: we do not record or replay a previous "resolve by
557 * deletion" for a delete-modify conflict, as that is inherently risky
558 * without knowing what modification is being discarded. The only
559 * safe case, i.e. both side doing the deletion and modification that
560 * are identical to the previous round, might want to be handled,
561 * though.
562 */
563static int find_conflict(struct string_list *conflict)
564{
565 int i;
566 if (read_cache() < 0)
567 return error(_("index file corrupt"));
568
569 for (i = 0; i < active_nr;) {
570 int conflict_type;
571 const struct cache_entry *e = active_cache[i];
572 i = check_one_conflict(i, &conflict_type);
573 if (conflict_type == THREE_STAGED)
574 string_list_insert(conflict, (const char *)e->name);
575 }
576 return 0;
577}
578
579/*
580 * The merge_rr list is meant to hold outstanding conflicted paths
581 * that rerere could handle. Abuse the list by adding other types of
582 * entries to allow the caller to show "rerere remaining".
583 *
584 * - Conflicted paths that rerere does not handle are added
585 * - Conflicted paths that have been resolved are marked as such
586 * by storing RERERE_RESOLVED to .util field (where conflict ID
587 * is expected to be stored).
588 *
589 * Do *not* write MERGE_RR file out after calling this function.
590 *
591 * NEEDSWORK: we may want to fix the caller that implements "rerere
592 * remaining" to do this without abusing merge_rr.
593 */
594int rerere_remaining(struct string_list *merge_rr)
595{
596 int i;
597 if (setup_rerere(merge_rr, RERERE_READONLY))
598 return 0;
599 if (read_cache() < 0)
600 return error(_("index file corrupt"));
601
602 for (i = 0; i < active_nr;) {
603 int conflict_type;
604 const struct cache_entry *e = active_cache[i];
605 i = check_one_conflict(i, &conflict_type);
606 if (conflict_type == PUNTED)
607 string_list_insert(merge_rr, (const char *)e->name);
608 else if (conflict_type == RESOLVED) {
609 struct string_list_item *it;
610 it = string_list_lookup(merge_rr, (const char *)e->name);
611 if (it != NULL) {
612 free_rerere_id(it);
613 it->util = RERERE_RESOLVED;
614 }
615 }
616 }
617 return 0;
618}
619
620/*
621 * Try using the given conflict resolution "ID" to see
622 * if that recorded conflict resolves cleanly what we
623 * got in the "cur".
624 */
625static int try_merge(const struct rerere_id *id, const char *path,
626 mmfile_t *cur, mmbuffer_t *result)
627{
628 int ret;
629 mmfile_t base = {NULL, 0}, other = {NULL, 0};
630
631 if (read_mmfile(&base, rerere_path(id, "preimage")) ||
632 read_mmfile(&other, rerere_path(id, "postimage")))
633 ret = 1;
634 else
635 /*
636 * A three-way merge. Note that this honors user-customizable
637 * low-level merge driver settings.
638 */
639 ret = ll_merge(result, path, &base, NULL, cur, "", &other, "", NULL);
640
641 free(base.ptr);
642 free(other.ptr);
643
644 return ret;
645}
646
647/*
648 * Find the conflict identified by "id"; the change between its
649 * "preimage" (i.e. a previous contents with conflict markers) and its
650 * "postimage" (i.e. the corresponding contents with conflicts
651 * resolved) may apply cleanly to the contents stored in "path", i.e.
652 * the conflict this time around.
653 *
654 * Returns 0 for successful replay of recorded resolution, or non-zero
655 * for failure.
656 */
657static int merge(const struct rerere_id *id, const char *path)
658{
659 FILE *f;
660 int ret;
661 mmfile_t cur = {NULL, 0};
662 mmbuffer_t result = {NULL, 0};
663
664 /*
665 * Normalize the conflicts in path and write it out to
666 * "thisimage" temporary file.
667 */
668 if ((handle_file(path, NULL, rerere_path(id, "thisimage")) < 0) ||
669 read_mmfile(&cur, rerere_path(id, "thisimage"))) {
670 ret = 1;
671 goto out;
672 }
673
674 ret = try_merge(id, path, &cur, &result);
675 if (ret)
676 goto out;
677
678 /*
679 * A successful replay of recorded resolution.
680 * Mark that "postimage" was used to help gc.
681 */
682 if (utime(rerere_path(id, "postimage"), NULL) < 0)
683 warning_errno(_("failed utime() on '%s'"),
684 rerere_path(id, "postimage"));
685
686 /* Update "path" with the resolution */
687 f = fopen(path, "w");
688 if (!f)
689 return error_errno(_("could not open '%s'"), path);
690 if (fwrite(result.ptr, result.size, 1, f) != 1)
691 error_errno(_("could not write '%s'"), path);
692 if (fclose(f))
693 return error_errno(_("writing '%s' failed"), path);
694
695out:
696 free(cur.ptr);
697 free(result.ptr);
698
699 return ret;
700}
701
702static void update_paths(struct string_list *update)
703{
704 struct lock_file index_lock = LOCK_INIT;
705 int i;
706
707 hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
708
709 for (i = 0; i < update->nr; i++) {
710 struct string_list_item *item = &update->items[i];
711 if (add_file_to_cache(item->string, 0))
712 exit(128);
713 fprintf_ln(stderr, _("Staged '%s' using previous resolution."),
714 item->string);
715 }
716
717 if (write_locked_index(&the_index, &index_lock,
718 COMMIT_LOCK | SKIP_IF_UNCHANGED))
719 die(_("unable to write new index file"));
720}
721
722static void remove_variant(struct rerere_id *id)
723{
724 unlink_or_warn(rerere_path(id, "postimage"));
725 unlink_or_warn(rerere_path(id, "preimage"));
726 id->collection->status[id->variant] = 0;
727}
728
729/*
730 * The path indicated by rr_item may still have conflict for which we
731 * have a recorded resolution, in which case replay it and optionally
732 * update it. Or it may have been resolved by the user and we may
733 * only have the preimage for that conflict, in which case the result
734 * needs to be recorded as a resolution in a postimage file.
735 */
736static void do_rerere_one_path(struct string_list_item *rr_item,
737 struct string_list *update)
738{
739 const char *path = rr_item->string;
740 struct rerere_id *id = rr_item->util;
741 struct rerere_dir *rr_dir = id->collection;
742 int variant;
743
744 variant = id->variant;
745
746 /* Has the user resolved it already? */
747 if (variant >= 0) {
748 if (!handle_file(path, NULL, NULL)) {
749 copy_file(rerere_path(id, "postimage"), path, 0666);
750 id->collection->status[variant] |= RR_HAS_POSTIMAGE;
751 fprintf_ln(stderr, _("Recorded resolution for '%s'."), path);
752 free_rerere_id(rr_item);
753 rr_item->util = NULL;
754 return;
755 }
756 /*
757 * There may be other variants that can cleanly
758 * replay. Try them and update the variant number for
759 * this one.
760 */
761 }
762
763 /* Does any existing resolution apply cleanly? */
764 for (variant = 0; variant < rr_dir->status_nr; variant++) {
765 const int both = RR_HAS_PREIMAGE | RR_HAS_POSTIMAGE;
766 struct rerere_id vid = *id;
767
768 if ((rr_dir->status[variant] & both) != both)
769 continue;
770
771 vid.variant = variant;
772 if (merge(&vid, path))
773 continue; /* failed to replay */
774
775 /*
776 * If there already is a different variant that applies
777 * cleanly, there is no point maintaining our own variant.
778 */
779 if (0 <= id->variant && id->variant != variant)
780 remove_variant(id);
781
782 if (rerere_autoupdate)
783 string_list_insert(update, path);
784 else
785 fprintf_ln(stderr,
786 _("Resolved '%s' using previous resolution."),
787 path);
788 free_rerere_id(rr_item);
789 rr_item->util = NULL;
790 return;
791 }
792
793 /* None of the existing one applies; we need a new variant */
794 assign_variant(id);
795
796 variant = id->variant;
797 handle_file(path, NULL, rerere_path(id, "preimage"));
798 if (id->collection->status[variant] & RR_HAS_POSTIMAGE) {
799 const char *path = rerere_path(id, "postimage");
800 if (unlink(path))
801 die_errno(_("cannot unlink stray '%s'"), path);
802 id->collection->status[variant] &= ~RR_HAS_POSTIMAGE;
803 }
804 id->collection->status[variant] |= RR_HAS_PREIMAGE;
805 fprintf_ln(stderr, _("Recorded preimage for '%s'"), path);
806}
807
808static int do_plain_rerere(struct string_list *rr, int fd)
809{
810 struct string_list conflict = STRING_LIST_INIT_DUP;
811 struct string_list update = STRING_LIST_INIT_DUP;
812 int i;
813
814 find_conflict(&conflict);
815
816 /*
817 * MERGE_RR records paths with conflicts immediately after
818 * merge failed. Some of the conflicted paths might have been
819 * hand resolved in the working tree since then, but the
820 * initial run would catch all and register their preimages.
821 */
822 for (i = 0; i < conflict.nr; i++) {
823 struct rerere_id *id;
824 unsigned char sha1[20];
825 const char *path = conflict.items[i].string;
826 int ret;
827
828 if (string_list_has_string(rr, path))
829 continue;
830
831 /*
832 * Ask handle_file() to scan and assign a
833 * conflict ID. No need to write anything out
834 * yet.
835 */
836 ret = handle_file(path, sha1, NULL);
837 if (ret < 1)
838 continue;
839
840 id = new_rerere_id(sha1);
841 string_list_insert(rr, path)->util = id;
842
843 /* Ensure that the directory exists. */
844 mkdir_in_gitdir(rerere_path(id, NULL));
845 }
846
847 for (i = 0; i < rr->nr; i++)
848 do_rerere_one_path(&rr->items[i], &update);
849
850 if (update.nr)
851 update_paths(&update);
852
853 return write_rr(rr, fd);
854}
855
856static void git_rerere_config(void)
857{
858 git_config_get_bool("rerere.enabled", &rerere_enabled);
859 git_config_get_bool("rerere.autoupdate", &rerere_autoupdate);
860 git_config(git_default_config, NULL);
861}
862
863static GIT_PATH_FUNC(git_path_rr_cache, "rr-cache")
864
865static int is_rerere_enabled(void)
866{
867 int rr_cache_exists;
868
869 if (!rerere_enabled)
870 return 0;
871
872 rr_cache_exists = is_directory(git_path_rr_cache());
873 if (rerere_enabled < 0)
874 return rr_cache_exists;
875
876 if (!rr_cache_exists && mkdir_in_gitdir(git_path_rr_cache()))
877 die(_("could not create directory '%s'"), git_path_rr_cache());
878 return 1;
879}
880
881int setup_rerere(struct string_list *merge_rr, int flags)
882{
883 int fd;
884
885 git_rerere_config();
886 if (!is_rerere_enabled())
887 return -1;
888
889 if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
890 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
891 if (flags & RERERE_READONLY)
892 fd = 0;
893 else
894 fd = hold_lock_file_for_update(&write_lock, git_path_merge_rr(),
895 LOCK_DIE_ON_ERROR);
896 read_rr(merge_rr);
897 return fd;
898}
899
900/*
901 * The main entry point that is called internally from codepaths that
902 * perform mergy operations, possibly leaving conflicted index entries
903 * and working tree files.
904 */
905int rerere(int flags)
906{
907 struct string_list merge_rr = STRING_LIST_INIT_DUP;
908 int fd, status;
909
910 fd = setup_rerere(&merge_rr, flags);
911 if (fd < 0)
912 return 0;
913 status = do_plain_rerere(&merge_rr, fd);
914 free_rerere_dirs();
915 return status;
916}
917
918/*
919 * Subclass of rerere_io that reads from an in-core buffer that is a
920 * strbuf
921 */
922struct rerere_io_mem {
923 struct rerere_io io;
924 struct strbuf input;
925};
926
927/*
928 * ... and its getline() method implementation
929 */
930static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
931{
932 struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
933 char *ep;
934 size_t len;
935
936 strbuf_release(sb);
937 if (!io->input.len)
938 return -1;
939 ep = memchr(io->input.buf, '\n', io->input.len);
940 if (!ep)
941 ep = io->input.buf + io->input.len;
942 else if (*ep == '\n')
943 ep++;
944 len = ep - io->input.buf;
945 strbuf_add(sb, io->input.buf, len);
946 strbuf_remove(&io->input, 0, len);
947 return 0;
948}
949
950static int handle_cache(const char *path, unsigned char *sha1, const char *output)
951{
952 mmfile_t mmfile[3] = {{NULL}};
953 mmbuffer_t result = {NULL, 0};
954 const struct cache_entry *ce;
955 int pos, len, i, hunk_no;
956 struct rerere_io_mem io;
957 int marker_size = ll_merge_marker_size(path);
958
959 /*
960 * Reproduce the conflicted merge in-core
961 */
962 len = strlen(path);
963 pos = cache_name_pos(path, len);
964 if (0 <= pos)
965 return -1;
966 pos = -pos - 1;
967
968 while (pos < active_nr) {
969 enum object_type type;
970 unsigned long size;
971
972 ce = active_cache[pos++];
973 if (ce_namelen(ce) != len || memcmp(ce->name, path, len))
974 break;
975 i = ce_stage(ce) - 1;
976 if (!mmfile[i].ptr) {
977 mmfile[i].ptr = read_object_file(&ce->oid, &type,
978 &size);
979 mmfile[i].size = size;
980 }
981 }
982 for (i = 0; i < 3; i++)
983 if (!mmfile[i].ptr && !mmfile[i].size)
984 mmfile[i].ptr = xstrdup("");
985
986 /*
987 * NEEDSWORK: handle conflicts from merges with
988 * merge.renormalize set, too?
989 */
990 ll_merge(&result, path, &mmfile[0], NULL,
991 &mmfile[1], "ours",
992 &mmfile[2], "theirs", NULL);
993 for (i = 0; i < 3; i++)
994 free(mmfile[i].ptr);
995
996 memset(&io, 0, sizeof(io));
997 io.io.getline = rerere_mem_getline;
998 if (output)
999 io.io.output = fopen(output, "w");
1000 else
1001 io.io.output = NULL;
1002 strbuf_init(&io.input, 0);
1003 strbuf_attach(&io.input, result.ptr, result.size, result.size);
1004
1005 /*
1006 * Grab the conflict ID and optionally write the original
1007 * contents with conflict markers out.
1008 */
1009 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
1010 strbuf_release(&io.input);
1011 if (io.io.output)
1012 fclose(io.io.output);
1013 return hunk_no;
1014}
1015
1016static int rerere_forget_one_path(const char *path, struct string_list *rr)
1017{
1018 const char *filename;
1019 struct rerere_id *id;
1020 unsigned char sha1[20];
1021 int ret;
1022 struct string_list_item *item;
1023
1024 /*
1025 * Recreate the original conflict from the stages in the
1026 * index and compute the conflict ID
1027 */
1028 ret = handle_cache(path, sha1, NULL);
1029 if (ret < 1)
1030 return error(_("could not parse conflict hunks in '%s'"), path);
1031
1032 /* Nuke the recorded resolution for the conflict */
1033 id = new_rerere_id(sha1);
1034
1035 for (id->variant = 0;
1036 id->variant < id->collection->status_nr;
1037 id->variant++) {
1038 mmfile_t cur = { NULL, 0 };
1039 mmbuffer_t result = {NULL, 0};
1040 int cleanly_resolved;
1041
1042 if (!has_rerere_resolution(id))
1043 continue;
1044
1045 handle_cache(path, sha1, rerere_path(id, "thisimage"));
1046 if (read_mmfile(&cur, rerere_path(id, "thisimage"))) {
1047 free(cur.ptr);
1048 error(_("failed to update conflicted state in '%s'"), path);
1049 goto fail_exit;
1050 }
1051 cleanly_resolved = !try_merge(id, path, &cur, &result);
1052 free(result.ptr);
1053 free(cur.ptr);
1054 if (cleanly_resolved)
1055 break;
1056 }
1057
1058 if (id->collection->status_nr <= id->variant) {
1059 error(_("no remembered resolution for '%s'"), path);
1060 goto fail_exit;
1061 }
1062
1063 filename = rerere_path(id, "postimage");
1064 if (unlink(filename)) {
1065 if (errno == ENOENT)
1066 error(_("no remembered resolution for '%s'"), path);
1067 else
1068 error_errno(_("cannot unlink '%s'"), filename);
1069 goto fail_exit;
1070 }
1071
1072 /*
1073 * Update the preimage so that the user can resolve the
1074 * conflict in the working tree, run us again to record
1075 * the postimage.
1076 */
1077 handle_cache(path, sha1, rerere_path(id, "preimage"));
1078 fprintf_ln(stderr, _("Updated preimage for '%s'"), path);
1079
1080 /*
1081 * And remember that we can record resolution for this
1082 * conflict when the user is done.
1083 */
1084 item = string_list_insert(rr, path);
1085 free_rerere_id(item);
1086 item->util = id;
1087 fprintf(stderr, _("Forgot resolution for '%s'\n"), path);
1088 return 0;
1089
1090fail_exit:
1091 free(id);
1092 return -1;
1093}
1094
1095int rerere_forget(struct pathspec *pathspec)
1096{
1097 int i, fd;
1098 struct string_list conflict = STRING_LIST_INIT_DUP;
1099 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1100
1101 if (read_cache() < 0)
1102 return error(_("index file corrupt"));
1103
1104 fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
1105 if (fd < 0)
1106 return 0;
1107
1108 /*
1109 * The paths may have been resolved (incorrectly);
1110 * recover the original conflicted state and then
1111 * find the conflicted paths.
1112 */
1113 unmerge_cache(pathspec);
1114 find_conflict(&conflict);
1115 for (i = 0; i < conflict.nr; i++) {
1116 struct string_list_item *it = &conflict.items[i];
1117 if (!match_pathspec(pathspec, it->string,
1118 strlen(it->string), 0, NULL, 0))
1119 continue;
1120 rerere_forget_one_path(it->string, &merge_rr);
1121 }
1122 return write_rr(&merge_rr, fd);
1123}
1124
1125/*
1126 * Garbage collection support
1127 */
1128
1129static timestamp_t rerere_created_at(struct rerere_id *id)
1130{
1131 struct stat st;
1132
1133 return stat(rerere_path(id, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
1134}
1135
1136static timestamp_t rerere_last_used_at(struct rerere_id *id)
1137{
1138 struct stat st;
1139
1140 return stat(rerere_path(id, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
1141}
1142
1143/*
1144 * Remove the recorded resolution for a given conflict ID
1145 */
1146static void unlink_rr_item(struct rerere_id *id)
1147{
1148 unlink_or_warn(rerere_path(id, "thisimage"));
1149 remove_variant(id);
1150 id->collection->status[id->variant] = 0;
1151}
1152
1153static void prune_one(struct rerere_id *id,
1154 timestamp_t cutoff_resolve, timestamp_t cutoff_noresolve)
1155{
1156 timestamp_t then;
1157 timestamp_t cutoff;
1158
1159 then = rerere_last_used_at(id);
1160 if (then)
1161 cutoff = cutoff_resolve;
1162 else {
1163 then = rerere_created_at(id);
1164 if (!then)
1165 return;
1166 cutoff = cutoff_noresolve;
1167 }
1168 if (then < cutoff)
1169 unlink_rr_item(id);
1170}
1171
1172void rerere_gc(struct string_list *rr)
1173{
1174 struct string_list to_remove = STRING_LIST_INIT_DUP;
1175 DIR *dir;
1176 struct dirent *e;
1177 int i;
1178 timestamp_t now = time(NULL);
1179 timestamp_t cutoff_noresolve = now - 15 * 86400;
1180 timestamp_t cutoff_resolve = now - 60 * 86400;
1181
1182 if (setup_rerere(rr, 0) < 0)
1183 return;
1184
1185 git_config_get_expiry_in_days("gc.rerereresolved", &cutoff_resolve, now);
1186 git_config_get_expiry_in_days("gc.rerereunresolved", &cutoff_noresolve, now);
1187 git_config(git_default_config, NULL);
1188 dir = opendir(git_path("rr-cache"));
1189 if (!dir)
1190 die_errno(_("unable to open rr-cache directory"));
1191 /* Collect stale conflict IDs ... */
1192 while ((e = readdir(dir))) {
1193 struct rerere_dir *rr_dir;
1194 struct rerere_id id;
1195 int now_empty;
1196
1197 if (is_dot_or_dotdot(e->d_name))
1198 continue;
1199 rr_dir = find_rerere_dir(e->d_name);
1200 if (!rr_dir)
1201 continue; /* or should we remove e->d_name? */
1202
1203 now_empty = 1;
1204 for (id.variant = 0, id.collection = rr_dir;
1205 id.variant < id.collection->status_nr;
1206 id.variant++) {
1207 prune_one(&id, cutoff_resolve, cutoff_noresolve);
1208 if (id.collection->status[id.variant])
1209 now_empty = 0;
1210 }
1211 if (now_empty)
1212 string_list_append(&to_remove, e->d_name);
1213 }
1214 closedir(dir);
1215
1216 /* ... and then remove the empty directories */
1217 for (i = 0; i < to_remove.nr; i++)
1218 rmdir(git_path("rr-cache/%s", to_remove.items[i].string));
1219 string_list_clear(&to_remove, 0);
1220 rollback_lock_file(&write_lock);
1221}
1222
1223/*
1224 * During a conflict resolution, after "rerere" recorded the
1225 * preimages, abandon them if the user did not resolve them or
1226 * record their resolutions. And drop $GIT_DIR/MERGE_RR.
1227 *
1228 * NEEDSWORK: shouldn't we be calling this from "reset --hard"?
1229 */
1230void rerere_clear(struct string_list *merge_rr)
1231{
1232 int i;
1233
1234 if (setup_rerere(merge_rr, 0) < 0)
1235 return;
1236
1237 for (i = 0; i < merge_rr->nr; i++) {
1238 struct rerere_id *id = merge_rr->items[i].util;
1239 if (!has_rerere_resolution(id)) {
1240 unlink_rr_item(id);
1241 rmdir(rerere_path(id, NULL));
1242 }
1243 }
1244 unlink_or_warn(git_path_merge_rr());
1245 rollback_lock_file(&write_lock);
1246}