stash: teach 'push' (and 'create_stash') to honor pathspec
[git.git] / rerere.c
blob5d083ca572df0c8a2cb90c0b12c14e15b4134d48
1 #include "cache.h"
2 #include "lockfile.h"
3 #include "string-list.h"
4 #include "rerere.h"
5 #include "xdiff-interface.h"
6 #include "dir.h"
7 #include "resolve-undo.h"
8 #include "ll-merge.h"
9 #include "attr.h"
10 #include "pathspec.h"
11 #include "sha1-lookup.h"
13 #define RESOLVED 0
14 #define PUNTED 1
15 #define THREE_STAGED 2
16 void *RERERE_RESOLVED = &RERERE_RESOLVED;
18 /* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
19 static int rerere_enabled = -1;
21 /* automatically update cleanly resolved paths to the index */
22 static int rerere_autoupdate;
24 static int rerere_dir_nr;
25 static int rerere_dir_alloc;
27 #define RR_HAS_POSTIMAGE 1
28 #define RR_HAS_PREIMAGE 2
29 static struct rerere_dir {
30 unsigned char sha1[20];
31 int status_alloc, status_nr;
32 unsigned char *status;
33 } **rerere_dir;
35 static void free_rerere_dirs(void)
37 int i;
38 for (i = 0; i < rerere_dir_nr; i++) {
39 free(rerere_dir[i]->status);
40 free(rerere_dir[i]);
42 free(rerere_dir);
43 rerere_dir_nr = rerere_dir_alloc = 0;
44 rerere_dir = NULL;
47 static void free_rerere_id(struct string_list_item *item)
49 free(item->util);
52 static const char *rerere_id_hex(const struct rerere_id *id)
54 return sha1_to_hex(id->collection->sha1);
57 static void fit_variant(struct rerere_dir *rr_dir, int variant)
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;
68 static void assign_variant(struct rerere_id *id)
70 int variant;
71 struct rerere_dir *rr_dir = id->collection;
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;
79 fit_variant(rr_dir, variant);
80 id->variant = variant;
83 const char *rerere_path(const struct rerere_id *id, const char *file)
85 if (!file)
86 return git_path("rr-cache/%s", rerere_id_hex(id));
88 if (id->variant <= 0)
89 return git_path("rr-cache/%s/%s", rerere_id_hex(id), file);
91 return git_path("rr-cache/%s/%s.%d",
92 rerere_id_hex(id), file, id->variant);
95 static int is_rr_file(const char *name, const char *filename, int *variant)
97 const char *suffix;
98 char *ep;
100 if (!strcmp(name, filename)) {
101 *variant = 0;
102 return 1;
104 if (!skip_prefix(name, filename, &suffix) || *suffix != '.')
105 return 0;
107 errno = 0;
108 *variant = strtol(suffix + 1, &ep, 10);
109 if (errno || *ep)
110 return 0;
111 return 1;
114 static void scan_rerere_dir(struct rerere_dir *rr_dir)
116 struct dirent *de;
117 DIR *dir = opendir(git_path("rr-cache/%s", sha1_to_hex(rr_dir->sha1)));
119 if (!dir)
120 return;
121 while ((de = readdir(dir)) != NULL) {
122 int variant;
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;
132 closedir(dir);
135 static const unsigned char *rerere_dir_sha1(size_t i, void *table)
137 struct rerere_dir **rr_dir = table;
138 return rr_dir[i]->sha1;
141 static struct rerere_dir *find_rerere_dir(const char *hex)
143 unsigned char sha1[20];
144 struct rerere_dir *rr_dir;
145 int pos;
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;
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 memmove(rerere_dir + pos + 1, rerere_dir + pos,
163 (rerere_dir_nr - pos - 1) * sizeof(*rerere_dir));
164 rerere_dir[pos] = rr_dir;
165 scan_rerere_dir(rr_dir);
167 return rerere_dir[pos];
170 static int has_rerere_resolution(const struct rerere_id *id)
172 const int both = RR_HAS_POSTIMAGE|RR_HAS_PREIMAGE;
173 int variant = id->variant;
175 if (variant < 0)
176 return 0;
177 return ((id->collection->status[variant] & both) == both);
180 static struct rerere_id *new_rerere_id_hex(char *hex)
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;
188 static struct rerere_id *new_rerere_id(unsigned char *sha1)
190 return new_rerere_id_hex(sha1_to_hex(sha1));
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).
200 static void read_rr(struct string_list *rr)
202 struct strbuf buf = STRBUF_INIT;
203 FILE *in = fopen(git_path_merge_rr(), "r");
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;
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");
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");
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;
233 strbuf_release(&buf);
234 fclose(in);
237 static struct lock_file write_lock;
239 static int write_rr(struct string_list *rr, int out_fd)
241 int i;
242 for (i = 0; i < rr->nr; i++) {
243 struct strbuf buf = STRBUF_INIT;
244 struct rerere_id *id;
246 assert(rr->items[i].util != RERERE_RESOLVED);
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);
261 if (write_in_full(out_fd, buf.buf, buf.len) != buf.len)
262 die("unable to write rerere record");
264 strbuf_release(&buf);
266 if (commit_lock_file(&write_lock) != 0)
267 die("unable to write rerere record");
268 return 0;
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.
279 struct rerere_io {
280 int (*getline)(struct strbuf *, struct rerere_io *);
281 FILE *output;
282 int wrerror;
283 /* some more stuff */
286 static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
288 if (!count || *err)
289 return;
290 if (fwrite(p, count, 1, fp) != 1)
291 *err = errno;
294 static inline void ferr_puts(const char *s, FILE *fp, int *err)
296 ferr_write(s, strlen(s), fp, err);
299 static void rerere_io_putstr(const char *str, struct rerere_io *io)
301 if (io->output)
302 ferr_puts(str, io->output, &io->wrerror);
306 * Write a conflict marker to io->output (if defined).
308 static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
310 char buf[64];
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;
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.
327 if (size <= sz)
328 sz -= (sz - size) + 1;
329 memset(buf, ch, sz);
330 buf[sz] = '\0';
331 size -= sz;
333 rerere_io_putstr(buf, io);
337 static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
339 if (io->output)
340 ferr_write(mem, sz, io->output, &io->wrerror);
344 * Subclass of rerere_io that reads from an on-disk file
346 struct rerere_io_file {
347 struct rerere_io io;
348 FILE *input;
352 * ... and its getline() method implementation
354 static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
356 struct rerere_io_file *io = (struct rerere_io_file *)io_;
357 return strbuf_getwholeline(sb, io->input, '\n');
361 * Require the exact number of conflict marker letters, no more, no
362 * less, followed by SP or any whitespace
363 * (including LF).
365 static int is_cmarker(char *buf, int marker_char, int marker_size)
367 int want_sp;
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.
377 want_sp = (marker_char == '<') || (marker_char == '>');
379 while (marker_size--)
380 if (*buf++ != marker_char)
381 return 0;
382 if (want_sp && *buf != ' ')
383 return 0;
384 return isspace(*buf);
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.
396 * Return the number of conflict hunks found.
398 * NEEDSWORK: the logic and theory of operation behind this conflict
399 * normalization may deserve to be documented somewhere, perhaps in
400 * Documentation/technical/rerere.txt.
402 static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
404 git_SHA_CTX ctx;
405 int hunk_no = 0;
406 enum {
407 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL
408 } hunk = RR_CONTEXT;
409 struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
410 struct strbuf buf = STRBUF_INIT;
412 if (sha1)
413 git_SHA1_Init(&ctx);
415 while (!io->getline(&buf, io)) {
416 if (is_cmarker(buf.buf, '<', marker_size)) {
417 if (hunk != RR_CONTEXT)
418 goto bad;
419 hunk = RR_SIDE_1;
420 } else if (is_cmarker(buf.buf, '|', marker_size)) {
421 if (hunk != RR_SIDE_1)
422 goto bad;
423 hunk = RR_ORIGINAL;
424 } else if (is_cmarker(buf.buf, '=', marker_size)) {
425 if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
426 goto bad;
427 hunk = RR_SIDE_2;
428 } else if (is_cmarker(buf.buf, '>', marker_size)) {
429 if (hunk != RR_SIDE_2)
430 goto bad;
431 if (strbuf_cmp(&one, &two) > 0)
432 strbuf_swap(&one, &two);
433 hunk_no++;
434 hunk = RR_CONTEXT;
435 rerere_io_putconflict('<', marker_size, io);
436 rerere_io_putmem(one.buf, one.len, io);
437 rerere_io_putconflict('=', marker_size, io);
438 rerere_io_putmem(two.buf, two.len, io);
439 rerere_io_putconflict('>', marker_size, io);
440 if (sha1) {
441 git_SHA1_Update(&ctx, one.buf ? one.buf : "",
442 one.len + 1);
443 git_SHA1_Update(&ctx, two.buf ? two.buf : "",
444 two.len + 1);
446 strbuf_reset(&one);
447 strbuf_reset(&two);
448 } else if (hunk == RR_SIDE_1)
449 strbuf_addbuf(&one, &buf);
450 else if (hunk == RR_ORIGINAL)
451 ; /* discard */
452 else if (hunk == RR_SIDE_2)
453 strbuf_addbuf(&two, &buf);
454 else
455 rerere_io_putstr(buf.buf, io);
456 continue;
457 bad:
458 hunk = 99; /* force error exit */
459 break;
461 strbuf_release(&one);
462 strbuf_release(&two);
463 strbuf_release(&buf);
465 if (sha1)
466 git_SHA1_Final(sha1, &ctx);
467 if (hunk != RR_CONTEXT)
468 return -1;
469 return hunk_no;
473 * Scan the path for conflicts, do the "handle_path()" thing above, and
474 * return the number of conflict hunks found.
476 static int handle_file(const char *path, unsigned char *sha1, const char *output)
478 int hunk_no = 0;
479 struct rerere_io_file io;
480 int marker_size = ll_merge_marker_size(path);
482 memset(&io, 0, sizeof(io));
483 io.io.getline = rerere_file_getline;
484 io.input = fopen(path, "r");
485 io.io.wrerror = 0;
486 if (!io.input)
487 return error("Could not open %s", path);
489 if (output) {
490 io.io.output = fopen(output, "w");
491 if (!io.io.output) {
492 fclose(io.input);
493 return error("Could not write %s", output);
497 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
499 fclose(io.input);
500 if (io.io.wrerror)
501 error("There were errors while writing %s (%s)",
502 path, strerror(io.io.wrerror));
503 if (io.io.output && fclose(io.io.output))
504 io.io.wrerror = error_errno("Failed to flush %s", path);
506 if (hunk_no < 0) {
507 if (output)
508 unlink_or_warn(output);
509 return error("Could not parse conflict hunks in %s", path);
511 if (io.io.wrerror)
512 return -1;
513 return hunk_no;
517 * Look at a cache entry at "i" and see if it is not conflicting,
518 * conflicting and we are willing to handle, or conflicting and
519 * we are unable to handle, and return the determination in *type.
520 * Return the cache index to be looked at next, by skipping the
521 * stages we have already looked at in this invocation of this
522 * function.
524 static int check_one_conflict(int i, int *type)
526 const struct cache_entry *e = active_cache[i];
528 if (!ce_stage(e)) {
529 *type = RESOLVED;
530 return i + 1;
533 *type = PUNTED;
534 while (ce_stage(active_cache[i]) == 1)
535 i++;
537 /* Only handle regular files with both stages #2 and #3 */
538 if (i + 1 < active_nr) {
539 const struct cache_entry *e2 = active_cache[i];
540 const struct cache_entry *e3 = active_cache[i + 1];
541 if (ce_stage(e2) == 2 &&
542 ce_stage(e3) == 3 &&
543 ce_same_name(e, e3) &&
544 S_ISREG(e2->ce_mode) &&
545 S_ISREG(e3->ce_mode))
546 *type = THREE_STAGED;
549 /* Skip the entries with the same name */
550 while (i < active_nr && ce_same_name(e, active_cache[i]))
551 i++;
552 return i;
556 * Scan the index and find paths that have conflicts that rerere can
557 * handle, i.e. the ones that has both stages #2 and #3.
559 * NEEDSWORK: we do not record or replay a previous "resolve by
560 * deletion" for a delete-modify conflict, as that is inherently risky
561 * without knowing what modification is being discarded. The only
562 * safe case, i.e. both side doing the deletion and modification that
563 * are identical to the previous round, might want to be handled,
564 * though.
566 static int find_conflict(struct string_list *conflict)
568 int i;
569 if (read_cache() < 0)
570 return error("Could not read index");
572 for (i = 0; i < active_nr;) {
573 int conflict_type;
574 const struct cache_entry *e = active_cache[i];
575 i = check_one_conflict(i, &conflict_type);
576 if (conflict_type == THREE_STAGED)
577 string_list_insert(conflict, (const char *)e->name);
579 return 0;
583 * The merge_rr list is meant to hold outstanding conflicted paths
584 * that rerere could handle. Abuse the list by adding other types of
585 * entries to allow the caller to show "rerere remaining".
587 * - Conflicted paths that rerere does not handle are added
588 * - Conflicted paths that have been resolved are marked as such
589 * by storing RERERE_RESOLVED to .util field (where conflict ID
590 * is expected to be stored).
592 * Do *not* write MERGE_RR file out after calling this function.
594 * NEEDSWORK: we may want to fix the caller that implements "rerere
595 * remaining" to do this without abusing merge_rr.
597 int rerere_remaining(struct string_list *merge_rr)
599 int i;
600 if (setup_rerere(merge_rr, RERERE_READONLY))
601 return 0;
602 if (read_cache() < 0)
603 return error("Could not read index");
605 for (i = 0; i < active_nr;) {
606 int conflict_type;
607 const struct cache_entry *e = active_cache[i];
608 i = check_one_conflict(i, &conflict_type);
609 if (conflict_type == PUNTED)
610 string_list_insert(merge_rr, (const char *)e->name);
611 else if (conflict_type == RESOLVED) {
612 struct string_list_item *it;
613 it = string_list_lookup(merge_rr, (const char *)e->name);
614 if (it != NULL) {
615 free_rerere_id(it);
616 it->util = RERERE_RESOLVED;
620 return 0;
624 * Try using the given conflict resolution "ID" to see
625 * if that recorded conflict resolves cleanly what we
626 * got in the "cur".
628 static int try_merge(const struct rerere_id *id, const char *path,
629 mmfile_t *cur, mmbuffer_t *result)
631 int ret;
632 mmfile_t base = {NULL, 0}, other = {NULL, 0};
634 if (read_mmfile(&base, rerere_path(id, "preimage")) ||
635 read_mmfile(&other, rerere_path(id, "postimage")))
636 ret = 1;
637 else
639 * A three-way merge. Note that this honors user-customizable
640 * low-level merge driver settings.
642 ret = ll_merge(result, path, &base, NULL, cur, "", &other, "", NULL);
644 free(base.ptr);
645 free(other.ptr);
647 return ret;
651 * Find the conflict identified by "id"; the change between its
652 * "preimage" (i.e. a previous contents with conflict markers) and its
653 * "postimage" (i.e. the corresponding contents with conflicts
654 * resolved) may apply cleanly to the contents stored in "path", i.e.
655 * the conflict this time around.
657 * Returns 0 for successful replay of recorded resolution, or non-zero
658 * for failure.
660 static int merge(const struct rerere_id *id, const char *path)
662 FILE *f;
663 int ret;
664 mmfile_t cur = {NULL, 0};
665 mmbuffer_t result = {NULL, 0};
668 * Normalize the conflicts in path and write it out to
669 * "thisimage" temporary file.
671 if ((handle_file(path, NULL, rerere_path(id, "thisimage")) < 0) ||
672 read_mmfile(&cur, rerere_path(id, "thisimage"))) {
673 ret = 1;
674 goto out;
677 ret = try_merge(id, path, &cur, &result);
678 if (ret)
679 goto out;
682 * A successful replay of recorded resolution.
683 * Mark that "postimage" was used to help gc.
685 if (utime(rerere_path(id, "postimage"), NULL) < 0)
686 warning_errno("failed utime() on %s",
687 rerere_path(id, "postimage"));
689 /* Update "path" with the resolution */
690 f = fopen(path, "w");
691 if (!f)
692 return error_errno("Could not open %s", path);
693 if (fwrite(result.ptr, result.size, 1, f) != 1)
694 error_errno("Could not write %s", path);
695 if (fclose(f))
696 return error_errno("Writing %s failed", path);
698 out:
699 free(cur.ptr);
700 free(result.ptr);
702 return ret;
705 static struct lock_file index_lock;
707 static void update_paths(struct string_list *update)
709 int i;
711 hold_locked_index(&index_lock, 1);
713 for (i = 0; i < update->nr; i++) {
714 struct string_list_item *item = &update->items[i];
715 if (add_file_to_cache(item->string, 0))
716 exit(128);
717 fprintf(stderr, "Staged '%s' using previous resolution.\n",
718 item->string);
721 if (active_cache_changed) {
722 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
723 die("Unable to write new index file");
724 } else
725 rollback_lock_file(&index_lock);
728 static void remove_variant(struct rerere_id *id)
730 unlink_or_warn(rerere_path(id, "postimage"));
731 unlink_or_warn(rerere_path(id, "preimage"));
732 id->collection->status[id->variant] = 0;
736 * The path indicated by rr_item may still have conflict for which we
737 * have a recorded resolution, in which case replay it and optionally
738 * update it. Or it may have been resolved by the user and we may
739 * only have the preimage for that conflict, in which case the result
740 * needs to be recorded as a resolution in a postimage file.
742 static void do_rerere_one_path(struct string_list_item *rr_item,
743 struct string_list *update)
745 const char *path = rr_item->string;
746 struct rerere_id *id = rr_item->util;
747 struct rerere_dir *rr_dir = id->collection;
748 int variant;
750 variant = id->variant;
752 /* Has the user resolved it already? */
753 if (variant >= 0) {
754 if (!handle_file(path, NULL, NULL)) {
755 copy_file(rerere_path(id, "postimage"), path, 0666);
756 id->collection->status[variant] |= RR_HAS_POSTIMAGE;
757 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
758 free_rerere_id(rr_item);
759 rr_item->util = NULL;
760 return;
763 * There may be other variants that can cleanly
764 * replay. Try them and update the variant number for
765 * this one.
769 /* Does any existing resolution apply cleanly? */
770 for (variant = 0; variant < rr_dir->status_nr; variant++) {
771 const int both = RR_HAS_PREIMAGE | RR_HAS_POSTIMAGE;
772 struct rerere_id vid = *id;
774 if ((rr_dir->status[variant] & both) != both)
775 continue;
777 vid.variant = variant;
778 if (merge(&vid, path))
779 continue; /* failed to replay */
782 * If there already is a different variant that applies
783 * cleanly, there is no point maintaining our own variant.
785 if (0 <= id->variant && id->variant != variant)
786 remove_variant(id);
788 if (rerere_autoupdate)
789 string_list_insert(update, path);
790 else
791 fprintf(stderr,
792 "Resolved '%s' using previous resolution.\n",
793 path);
794 free_rerere_id(rr_item);
795 rr_item->util = NULL;
796 return;
799 /* None of the existing one applies; we need a new variant */
800 assign_variant(id);
802 variant = id->variant;
803 handle_file(path, NULL, rerere_path(id, "preimage"));
804 if (id->collection->status[variant] & RR_HAS_POSTIMAGE) {
805 const char *path = rerere_path(id, "postimage");
806 if (unlink(path))
807 die_errno("cannot unlink stray '%s'", path);
808 id->collection->status[variant] &= ~RR_HAS_POSTIMAGE;
810 id->collection->status[variant] |= RR_HAS_PREIMAGE;
811 fprintf(stderr, "Recorded preimage for '%s'\n", path);
814 static int do_plain_rerere(struct string_list *rr, int fd)
816 struct string_list conflict = STRING_LIST_INIT_DUP;
817 struct string_list update = STRING_LIST_INIT_DUP;
818 int i;
820 find_conflict(&conflict);
823 * MERGE_RR records paths with conflicts immediately after
824 * merge failed. Some of the conflicted paths might have been
825 * hand resolved in the working tree since then, but the
826 * initial run would catch all and register their preimages.
828 for (i = 0; i < conflict.nr; i++) {
829 struct rerere_id *id;
830 unsigned char sha1[20];
831 const char *path = conflict.items[i].string;
832 int ret;
834 if (string_list_has_string(rr, path))
835 continue;
838 * Ask handle_file() to scan and assign a
839 * conflict ID. No need to write anything out
840 * yet.
842 ret = handle_file(path, sha1, NULL);
843 if (ret < 1)
844 continue;
846 id = new_rerere_id(sha1);
847 string_list_insert(rr, path)->util = id;
849 /* Ensure that the directory exists. */
850 mkdir_in_gitdir(rerere_path(id, NULL));
853 for (i = 0; i < rr->nr; i++)
854 do_rerere_one_path(&rr->items[i], &update);
856 if (update.nr)
857 update_paths(&update);
859 return write_rr(rr, fd);
862 static void git_rerere_config(void)
864 git_config_get_bool("rerere.enabled", &rerere_enabled);
865 git_config_get_bool("rerere.autoupdate", &rerere_autoupdate);
866 git_config(git_default_config, NULL);
869 static GIT_PATH_FUNC(git_path_rr_cache, "rr-cache")
871 static int is_rerere_enabled(void)
873 int rr_cache_exists;
875 if (!rerere_enabled)
876 return 0;
878 rr_cache_exists = is_directory(git_path_rr_cache());
879 if (rerere_enabled < 0)
880 return rr_cache_exists;
882 if (!rr_cache_exists && mkdir_in_gitdir(git_path_rr_cache()))
883 die("Could not create directory %s", git_path_rr_cache());
884 return 1;
887 int setup_rerere(struct string_list *merge_rr, int flags)
889 int fd;
891 git_rerere_config();
892 if (!is_rerere_enabled())
893 return -1;
895 if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
896 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
897 if (flags & RERERE_READONLY)
898 fd = 0;
899 else
900 fd = hold_lock_file_for_update(&write_lock, git_path_merge_rr(),
901 LOCK_DIE_ON_ERROR);
902 read_rr(merge_rr);
903 return fd;
907 * The main entry point that is called internally from codepaths that
908 * perform mergy operations, possibly leaving conflicted index entries
909 * and working tree files.
911 int rerere(int flags)
913 struct string_list merge_rr = STRING_LIST_INIT_DUP;
914 int fd, status;
916 fd = setup_rerere(&merge_rr, flags);
917 if (fd < 0)
918 return 0;
919 status = do_plain_rerere(&merge_rr, fd);
920 free_rerere_dirs();
921 return status;
925 * Subclass of rerere_io that reads from an in-core buffer that is a
926 * strbuf
928 struct rerere_io_mem {
929 struct rerere_io io;
930 struct strbuf input;
934 * ... and its getline() method implementation
936 static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
938 struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
939 char *ep;
940 size_t len;
942 strbuf_release(sb);
943 if (!io->input.len)
944 return -1;
945 ep = memchr(io->input.buf, '\n', io->input.len);
946 if (!ep)
947 ep = io->input.buf + io->input.len;
948 else if (*ep == '\n')
949 ep++;
950 len = ep - io->input.buf;
951 strbuf_add(sb, io->input.buf, len);
952 strbuf_remove(&io->input, 0, len);
953 return 0;
956 static int handle_cache(const char *path, unsigned char *sha1, const char *output)
958 mmfile_t mmfile[3] = {{NULL}};
959 mmbuffer_t result = {NULL, 0};
960 const struct cache_entry *ce;
961 int pos, len, i, hunk_no;
962 struct rerere_io_mem io;
963 int marker_size = ll_merge_marker_size(path);
966 * Reproduce the conflicted merge in-core
968 len = strlen(path);
969 pos = cache_name_pos(path, len);
970 if (0 <= pos)
971 return -1;
972 pos = -pos - 1;
974 while (pos < active_nr) {
975 enum object_type type;
976 unsigned long size;
978 ce = active_cache[pos++];
979 if (ce_namelen(ce) != len || memcmp(ce->name, path, len))
980 break;
981 i = ce_stage(ce) - 1;
982 if (!mmfile[i].ptr) {
983 mmfile[i].ptr = read_sha1_file(ce->oid.hash, &type,
984 &size);
985 mmfile[i].size = size;
988 for (i = 0; i < 3; i++)
989 if (!mmfile[i].ptr && !mmfile[i].size)
990 mmfile[i].ptr = xstrdup("");
993 * NEEDSWORK: handle conflicts from merges with
994 * merge.renormalize set, too?
996 ll_merge(&result, path, &mmfile[0], NULL,
997 &mmfile[1], "ours",
998 &mmfile[2], "theirs", NULL);
999 for (i = 0; i < 3; i++)
1000 free(mmfile[i].ptr);
1002 memset(&io, 0, sizeof(io));
1003 io.io.getline = rerere_mem_getline;
1004 if (output)
1005 io.io.output = fopen(output, "w");
1006 else
1007 io.io.output = NULL;
1008 strbuf_init(&io.input, 0);
1009 strbuf_attach(&io.input, result.ptr, result.size, result.size);
1012 * Grab the conflict ID and optionally write the original
1013 * contents with conflict markers out.
1015 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
1016 strbuf_release(&io.input);
1017 if (io.io.output)
1018 fclose(io.io.output);
1019 return hunk_no;
1022 static int rerere_forget_one_path(const char *path, struct string_list *rr)
1024 const char *filename;
1025 struct rerere_id *id;
1026 unsigned char sha1[20];
1027 int ret;
1028 struct string_list_item *item;
1031 * Recreate the original conflict from the stages in the
1032 * index and compute the conflict ID
1034 ret = handle_cache(path, sha1, NULL);
1035 if (ret < 1)
1036 return error("Could not parse conflict hunks in '%s'", path);
1038 /* Nuke the recorded resolution for the conflict */
1039 id = new_rerere_id(sha1);
1041 for (id->variant = 0;
1042 id->variant < id->collection->status_nr;
1043 id->variant++) {
1044 mmfile_t cur = { NULL, 0 };
1045 mmbuffer_t result = {NULL, 0};
1046 int cleanly_resolved;
1048 if (!has_rerere_resolution(id))
1049 continue;
1051 handle_cache(path, sha1, rerere_path(id, "thisimage"));
1052 if (read_mmfile(&cur, rerere_path(id, "thisimage"))) {
1053 free(cur.ptr);
1054 error("Failed to update conflicted state in '%s'", path);
1055 goto fail_exit;
1057 cleanly_resolved = !try_merge(id, path, &cur, &result);
1058 free(result.ptr);
1059 free(cur.ptr);
1060 if (cleanly_resolved)
1061 break;
1064 if (id->collection->status_nr <= id->variant) {
1065 error("no remembered resolution for '%s'", path);
1066 goto fail_exit;
1069 filename = rerere_path(id, "postimage");
1070 if (unlink(filename)) {
1071 if (errno == ENOENT)
1072 error("no remembered resolution for %s", path);
1073 else
1074 error_errno("cannot unlink %s", filename);
1075 goto fail_exit;
1079 * Update the preimage so that the user can resolve the
1080 * conflict in the working tree, run us again to record
1081 * the postimage.
1083 handle_cache(path, sha1, rerere_path(id, "preimage"));
1084 fprintf(stderr, "Updated preimage for '%s'\n", path);
1087 * And remember that we can record resolution for this
1088 * conflict when the user is done.
1090 item = string_list_insert(rr, path);
1091 free_rerere_id(item);
1092 item->util = id;
1093 fprintf(stderr, "Forgot resolution for %s\n", path);
1094 return 0;
1096 fail_exit:
1097 free(id);
1098 return -1;
1101 int rerere_forget(struct pathspec *pathspec)
1103 int i, fd;
1104 struct string_list conflict = STRING_LIST_INIT_DUP;
1105 struct string_list merge_rr = STRING_LIST_INIT_DUP;
1107 if (read_cache() < 0)
1108 return error("Could not read index");
1110 fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
1111 if (fd < 0)
1112 return 0;
1115 * The paths may have been resolved (incorrectly);
1116 * recover the original conflicted state and then
1117 * find the conflicted paths.
1119 unmerge_cache(pathspec);
1120 find_conflict(&conflict);
1121 for (i = 0; i < conflict.nr; i++) {
1122 struct string_list_item *it = &conflict.items[i];
1123 if (!match_pathspec(pathspec, it->string,
1124 strlen(it->string), 0, NULL, 0))
1125 continue;
1126 rerere_forget_one_path(it->string, &merge_rr);
1128 return write_rr(&merge_rr, fd);
1132 * Garbage collection support
1135 static time_t rerere_created_at(struct rerere_id *id)
1137 struct stat st;
1139 return stat(rerere_path(id, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
1142 static time_t rerere_last_used_at(struct rerere_id *id)
1144 struct stat st;
1146 return stat(rerere_path(id, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
1150 * Remove the recorded resolution for a given conflict ID
1152 static void unlink_rr_item(struct rerere_id *id)
1154 unlink_or_warn(rerere_path(id, "thisimage"));
1155 remove_variant(id);
1156 id->collection->status[id->variant] = 0;
1159 static void prune_one(struct rerere_id *id, time_t now,
1160 int cutoff_resolve, int cutoff_noresolve)
1162 time_t then;
1163 int cutoff;
1165 then = rerere_last_used_at(id);
1166 if (then)
1167 cutoff = cutoff_resolve;
1168 else {
1169 then = rerere_created_at(id);
1170 if (!then)
1171 return;
1172 cutoff = cutoff_noresolve;
1174 if (then < now - cutoff * 86400)
1175 unlink_rr_item(id);
1178 void rerere_gc(struct string_list *rr)
1180 struct string_list to_remove = STRING_LIST_INIT_DUP;
1181 DIR *dir;
1182 struct dirent *e;
1183 int i;
1184 time_t now = time(NULL);
1185 int cutoff_noresolve = 15;
1186 int cutoff_resolve = 60;
1188 if (setup_rerere(rr, 0) < 0)
1189 return;
1191 git_config_get_int("gc.rerereresolved", &cutoff_resolve);
1192 git_config_get_int("gc.rerereunresolved", &cutoff_noresolve);
1193 git_config(git_default_config, NULL);
1194 dir = opendir(git_path("rr-cache"));
1195 if (!dir)
1196 die_errno("unable to open rr-cache directory");
1197 /* Collect stale conflict IDs ... */
1198 while ((e = readdir(dir))) {
1199 struct rerere_dir *rr_dir;
1200 struct rerere_id id;
1201 int now_empty;
1203 if (is_dot_or_dotdot(e->d_name))
1204 continue;
1205 rr_dir = find_rerere_dir(e->d_name);
1206 if (!rr_dir)
1207 continue; /* or should we remove e->d_name? */
1209 now_empty = 1;
1210 for (id.variant = 0, id.collection = rr_dir;
1211 id.variant < id.collection->status_nr;
1212 id.variant++) {
1213 prune_one(&id, now, cutoff_resolve, cutoff_noresolve);
1214 if (id.collection->status[id.variant])
1215 now_empty = 0;
1217 if (now_empty)
1218 string_list_append(&to_remove, e->d_name);
1220 closedir(dir);
1222 /* ... and then remove the empty directories */
1223 for (i = 0; i < to_remove.nr; i++)
1224 rmdir(git_path("rr-cache/%s", to_remove.items[i].string));
1225 string_list_clear(&to_remove, 0);
1226 rollback_lock_file(&write_lock);
1230 * During a conflict resolution, after "rerere" recorded the
1231 * preimages, abandon them if the user did not resolve them or
1232 * record their resolutions. And drop $GIT_DIR/MERGE_RR.
1234 * NEEDSWORK: shouldn't we be calling this from "reset --hard"?
1236 void rerere_clear(struct string_list *merge_rr)
1238 int i;
1240 if (setup_rerere(merge_rr, 0) < 0)
1241 return;
1243 for (i = 0; i < merge_rr->nr; i++) {
1244 struct rerere_id *id = merge_rr->items[i].util;
1245 if (!has_rerere_resolution(id)) {
1246 unlink_rr_item(id);
1247 rmdir(rerere_path(id, NULL));
1250 unlink_or_warn(git_path_merge_rr());
1251 rollback_lock_file(&write_lock);