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rerere: explain MERGE_RR management helpers
[thirdparty/git.git] / rerere.c
CommitLineData
5b2fd956 1#include "cache.h"
697cc8ef 2#include "lockfile.h"
c455c87c 3#include "string-list.h"
5b2fd956 4#include "rerere.h"
5b2fd956 5#include "xdiff-interface.h"
dea4562b
JH
6#include "dir.h"
7#include "resolve-undo.h"
8#include "ll-merge.h"
8588567c 9#include "attr.h"
01a10b0a 10#include "pathspec.h"
5b2fd956 11
ac49f5ca
MZ
12#define RESOLVED 0
13#define PUNTED 1
14#define THREE_STAGED 2
15void *RERERE_RESOLVED = &RERERE_RESOLVED;
16
5b2fd956
SB
17/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
18static int rerere_enabled = -1;
19
20/* automatically update cleanly resolved paths to the index */
21static int rerere_autoupdate;
22
23static char *merge_rr_path;
24
90056966 25const char *rerere_path(const char *hex, const char *file)
5b2fd956 26{
90056966 27 return git_path("rr-cache/%s/%s", hex, file);
5b2fd956
SB
28}
29
7e0d4ab5 30static int has_rerere_resolution(const char *hex)
5b2fd956
SB
31{
32 struct stat st;
90056966 33 return !stat(rerere_path(hex, "postimage"), &st);
5b2fd956
SB
34}
35
4b68c2a0
JH
36/*
37 * $GIT_DIR/MERGE_RR file is a collection of records, each of which is
38 * "conflict ID", a HT and pathname, terminated with a NUL, and is
39 * used to keep track of the set of paths that "rerere" may need to
40 * work on (i.e. what is left by the previous invocation of "git
41 * rerere" during the current conflict resolution session).
42 */
c455c87c 43static void read_rr(struct string_list *rr)
5b2fd956 44{
f5800f6a 45 struct strbuf buf = STRBUF_INIT;
5b2fd956 46 FILE *in = fopen(merge_rr_path, "r");
f5800f6a 47
5b2fd956
SB
48 if (!in)
49 return;
f5800f6a
JH
50 while (!strbuf_getwholeline(&buf, in, '\0')) {
51 char *path;
52 unsigned char sha1[20];
53
54 /* There has to be the hash, tab, path and then NUL */
55 if (buf.len < 42 || get_sha1_hex(buf.buf, sha1))
5b2fd956 56 die("corrupt MERGE_RR");
f5800f6a
JH
57
58 if (buf.buf[40] != '\t')
5b2fd956 59 die("corrupt MERGE_RR");
f5800f6a
JH
60 buf.buf[40] = '\0';
61 path = buf.buf + 41;
62
63 string_list_insert(rr, path)->util = xstrdup(buf.buf);
5b2fd956 64 }
f5800f6a 65 strbuf_release(&buf);
5b2fd956
SB
66 fclose(in);
67}
68
69static struct lock_file write_lock;
70
c455c87c 71static int write_rr(struct string_list *rr, int out_fd)
5b2fd956
SB
72{
73 int i;
74 for (i = 0; i < rr->nr; i++) {
e2cb6a95
JH
75 struct strbuf buf = STRBUF_INIT;
76
77 assert(rr->items[i].util != RERERE_RESOLVED);
5b2fd956
SB
78 if (!rr->items[i].util)
79 continue;
e2cb6a95
JH
80 strbuf_addf(&buf, "%s\t%s%c",
81 (char *)rr->items[i].util,
82 rr->items[i].string, 0);
83 if (write_in_full(out_fd, buf.buf, buf.len) != buf.len)
5b2fd956 84 die("unable to write rerere record");
e2cb6a95
JH
85
86 strbuf_release(&buf);
5b2fd956
SB
87 }
88 if (commit_lock_file(&write_lock) != 0)
89 die("unable to write rerere record");
90 return 0;
91}
92
a96847cc
JH
93/*
94 * "rerere" interacts with conflicted file contents using this I/O
95 * abstraction. It reads a conflicted contents from one place via
96 * "getline()" method, and optionally can write it out after
97 * normalizing the conflicted hunks to the "output". Subclasses of
98 * rerere_io embed this structure at the beginning of their own
99 * rerere_io object.
100 */
101struct rerere_io {
102 int (*getline)(struct strbuf *, struct rerere_io *);
103 FILE *output;
104 int wrerror;
105 /* some more stuff */
106};
107
47d32af2
AR
108static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
109{
110 if (!count || *err)
111 return;
112 if (fwrite(p, count, 1, fp) != 1)
113 *err = errno;
114}
115
116static inline void ferr_puts(const char *s, FILE *fp, int *err)
117{
118 ferr_write(s, strlen(s), fp, err);
119}
120
27d6b085
JH
121static void rerere_io_putstr(const char *str, struct rerere_io *io)
122{
123 if (io->output)
124 ferr_puts(str, io->output, &io->wrerror);
125}
126
a96847cc
JH
127/*
128 * Write a conflict marker to io->output (if defined).
129 */
191f2417
JH
130static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
131{
132 char buf[64];
133
134 while (size) {
d3c2749d 135 if (size <= sizeof(buf) - 2) {
191f2417
JH
136 memset(buf, ch, size);
137 buf[size] = '\n';
138 buf[size + 1] = '\0';
139 size = 0;
140 } else {
141 int sz = sizeof(buf) - 1;
d3c2749d
JH
142
143 /*
144 * Make sure we will not write everything out
145 * in this round by leaving at least 1 byte
146 * for the next round, giving the next round
147 * a chance to add the terminating LF. Yuck.
148 */
191f2417
JH
149 if (size <= sz)
150 sz -= (sz - size) + 1;
151 memset(buf, ch, sz);
152 buf[sz] = '\0';
153 size -= sz;
154 }
155 rerere_io_putstr(buf, io);
156 }
157}
158
27d6b085
JH
159static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
160{
161 if (io->output)
162 ferr_write(mem, sz, io->output, &io->wrerror);
163}
164
a96847cc
JH
165/*
166 * Subclass of rerere_io that reads from an on-disk file
167 */
27d6b085
JH
168struct rerere_io_file {
169 struct rerere_io io;
170 FILE *input;
171};
172
a96847cc
JH
173/*
174 * ... and its getline() method implementation
175 */
27d6b085
JH
176static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
177{
178 struct rerere_io_file *io = (struct rerere_io_file *)io_;
179 return strbuf_getwholeline(sb, io->input, '\n');
180}
181
67711cdc
JH
182/*
183 * Require the exact number of conflict marker letters, no more, no
184 * less, followed by SP or any whitespace
185 * (including LF).
186 */
187static int is_cmarker(char *buf, int marker_char, int marker_size)
191f2417 188{
67711cdc
JH
189 int want_sp;
190
191 /*
192 * The beginning of our version and the end of their version
193 * always are labeled like "<<<<< ours" or ">>>>> theirs",
194 * hence we set want_sp for them. Note that the version from
195 * the common ancestor in diff3-style output is not always
196 * labelled (e.g. "||||| common" is often seen but "|||||"
197 * alone is also valid), so we do not set want_sp.
198 */
199 want_sp = (marker_char == '<') || (marker_char == '>');
200
191f2417
JH
201 while (marker_size--)
202 if (*buf++ != marker_char)
203 return 0;
204 if (want_sp && *buf != ' ')
205 return 0;
206 return isspace(*buf);
207}
208
209static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
5b2fd956 210{
9126f009 211 git_SHA_CTX ctx;
cc58d7df
JH
212 int hunk_no = 0;
213 enum {
4b05548f 214 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL
cc58d7df 215 } hunk = RR_CONTEXT;
f285a2d7 216 struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
d58ee6db 217 struct strbuf buf = STRBUF_INIT;
5b2fd956
SB
218
219 if (sha1)
9126f009 220 git_SHA1_Init(&ctx);
5b2fd956 221
27d6b085 222 while (!io->getline(&buf, io)) {
67711cdc 223 if (is_cmarker(buf.buf, '<', marker_size)) {
cc58d7df 224 if (hunk != RR_CONTEXT)
5b2fd956 225 goto bad;
cc58d7df 226 hunk = RR_SIDE_1;
67711cdc 227 } else if (is_cmarker(buf.buf, '|', marker_size)) {
cc58d7df 228 if (hunk != RR_SIDE_1)
5b2fd956 229 goto bad;
387c9d49 230 hunk = RR_ORIGINAL;
67711cdc 231 } else if (is_cmarker(buf.buf, '=', marker_size)) {
387c9d49 232 if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
5b2fd956 233 goto bad;
cc58d7df 234 hunk = RR_SIDE_2;
67711cdc 235 } else if (is_cmarker(buf.buf, '>', marker_size)) {
cc58d7df 236 if (hunk != RR_SIDE_2)
5b2fd956
SB
237 goto bad;
238 if (strbuf_cmp(&one, &two) > 0)
239 strbuf_swap(&one, &two);
240 hunk_no++;
cc58d7df 241 hunk = RR_CONTEXT;
191f2417 242 rerere_io_putconflict('<', marker_size, io);
27d6b085 243 rerere_io_putmem(one.buf, one.len, io);
191f2417 244 rerere_io_putconflict('=', marker_size, io);
27d6b085 245 rerere_io_putmem(two.buf, two.len, io);
191f2417 246 rerere_io_putconflict('>', marker_size, io);
5b2fd956 247 if (sha1) {
9126f009 248 git_SHA1_Update(&ctx, one.buf ? one.buf : "",
5b2fd956 249 one.len + 1);
9126f009 250 git_SHA1_Update(&ctx, two.buf ? two.buf : "",
5b2fd956
SB
251 two.len + 1);
252 }
253 strbuf_reset(&one);
254 strbuf_reset(&two);
cc58d7df 255 } else if (hunk == RR_SIDE_1)
e992d1eb 256 strbuf_addbuf(&one, &buf);
387c9d49
JH
257 else if (hunk == RR_ORIGINAL)
258 ; /* discard */
cc58d7df 259 else if (hunk == RR_SIDE_2)
e992d1eb 260 strbuf_addbuf(&two, &buf);
27d6b085
JH
261 else
262 rerere_io_putstr(buf.buf, io);
5b2fd956
SB
263 continue;
264 bad:
265 hunk = 99; /* force error exit */
266 break;
267 }
268 strbuf_release(&one);
269 strbuf_release(&two);
d58ee6db 270 strbuf_release(&buf);
5b2fd956 271
5b2fd956 272 if (sha1)
9126f009 273 git_SHA1_Final(sha1, &ctx);
27d6b085
JH
274 if (hunk != RR_CONTEXT)
275 return -1;
276 return hunk_no;
277}
278
279static int handle_file(const char *path, unsigned char *sha1, const char *output)
280{
281 int hunk_no = 0;
282 struct rerere_io_file io;
8588567c 283 int marker_size = ll_merge_marker_size(path);
27d6b085
JH
284
285 memset(&io, 0, sizeof(io));
286 io.io.getline = rerere_file_getline;
287 io.input = fopen(path, "r");
288 io.io.wrerror = 0;
289 if (!io.input)
290 return error("Could not open %s", path);
291
292 if (output) {
293 io.io.output = fopen(output, "w");
294 if (!io.io.output) {
295 fclose(io.input);
296 return error("Could not write %s", output);
297 }
298 }
299
191f2417 300 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
27d6b085
JH
301
302 fclose(io.input);
303 if (io.io.wrerror)
304 error("There were errors while writing %s (%s)",
305 path, strerror(io.io.wrerror));
306 if (io.io.output && fclose(io.io.output))
307 io.io.wrerror = error("Failed to flush %s: %s",
308 path, strerror(errno));
309
310 if (hunk_no < 0) {
5b2fd956 311 if (output)
691f1a28 312 unlink_or_warn(output);
5b2fd956
SB
313 return error("Could not parse conflict hunks in %s", path);
314 }
27d6b085 315 if (io.io.wrerror)
47d32af2 316 return -1;
5b2fd956
SB
317 return hunk_no;
318}
319
a96847cc
JH
320/*
321 * Subclass of rerere_io that reads from an in-core buffer that is a
322 * strbuf
323 */
dea4562b
JH
324struct rerere_io_mem {
325 struct rerere_io io;
326 struct strbuf input;
327};
328
a96847cc
JH
329/*
330 * ... and its getline() method implementation
331 */
dea4562b
JH
332static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
333{
334 struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
335 char *ep;
336 size_t len;
337
338 strbuf_release(sb);
339 if (!io->input.len)
340 return -1;
53d8afaf
JS
341 ep = memchr(io->input.buf, '\n', io->input.len);
342 if (!ep)
343 ep = io->input.buf + io->input.len;
344 else if (*ep == '\n')
dea4562b
JH
345 ep++;
346 len = ep - io->input.buf;
347 strbuf_add(sb, io->input.buf, len);
348 strbuf_remove(&io->input, 0, len);
349 return 0;
350}
351
352static int handle_cache(const char *path, unsigned char *sha1, const char *output)
353{
b9e31f59 354 mmfile_t mmfile[3] = {{NULL}};
dea4562b 355 mmbuffer_t result = {NULL, 0};
9c5e6c80 356 const struct cache_entry *ce;
dea4562b
JH
357 int pos, len, i, hunk_no;
358 struct rerere_io_mem io;
8588567c 359 int marker_size = ll_merge_marker_size(path);
dea4562b
JH
360
361 /*
362 * Reproduce the conflicted merge in-core
363 */
364 len = strlen(path);
365 pos = cache_name_pos(path, len);
366 if (0 <= pos)
47d32af2 367 return -1;
dea4562b
JH
368 pos = -pos - 1;
369
74444d4e 370 while (pos < active_nr) {
dea4562b
JH
371 enum object_type type;
372 unsigned long size;
373
dea4562b 374 ce = active_cache[pos++];
b9e31f59 375 if (ce_namelen(ce) != len || memcmp(ce->name, path, len))
74444d4e
JH
376 break;
377 i = ce_stage(ce) - 1;
7d4053b6
JH
378 if (!mmfile[i].ptr) {
379 mmfile[i].ptr = read_sha1_file(ce->sha1, &type, &size);
380 mmfile[i].size = size;
381 }
dea4562b 382 }
74444d4e 383 for (i = 0; i < 3; i++)
dea4562b
JH
384 if (!mmfile[i].ptr && !mmfile[i].size)
385 mmfile[i].ptr = xstrdup("");
74444d4e 386
18b037a5
JN
387 /*
388 * NEEDSWORK: handle conflicts from merges with
389 * merge.renormalize set, too
390 */
f01de62e 391 ll_merge(&result, path, &mmfile[0], NULL,
dea4562b 392 &mmfile[1], "ours",
712516bc 393 &mmfile[2], "theirs", NULL);
dea4562b
JH
394 for (i = 0; i < 3; i++)
395 free(mmfile[i].ptr);
396
af86debc 397 memset(&io, 0, sizeof(io));
dea4562b
JH
398 io.io.getline = rerere_mem_getline;
399 if (output)
400 io.io.output = fopen(output, "w");
401 else
402 io.io.output = NULL;
403 strbuf_init(&io.input, 0);
404 strbuf_attach(&io.input, result.ptr, result.size, result.size);
405
191f2417 406 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
dea4562b
JH
407 strbuf_release(&io.input);
408 if (io.io.output)
409 fclose(io.io.output);
5b2fd956
SB
410 return hunk_no;
411}
412
4b68c2a0
JH
413/*
414 * Look at a cache entry at "i" and see if it is not conflicting,
415 * conflicting and we are willing to handle, or conflicting and
416 * we are unable to handle, and return the determination in *type.
417 * Return the cache index to be looked at next, by skipping the
418 * stages we have already looked at in this invocation of this
419 * function.
420 */
ac49f5ca 421static int check_one_conflict(int i, int *type)
5b2fd956 422{
9c5e6c80 423 const struct cache_entry *e = active_cache[i];
ac49f5ca
MZ
424
425 if (!ce_stage(e)) {
426 *type = RESOLVED;
427 return i + 1;
428 }
429
430 *type = PUNTED;
5eda906b 431 while (ce_stage(active_cache[i]) == 1)
fb70a06d 432 i++;
ac49f5ca
MZ
433
434 /* Only handle regular files with both stages #2 and #3 */
435 if (i + 1 < active_nr) {
9c5e6c80
NTND
436 const struct cache_entry *e2 = active_cache[i];
437 const struct cache_entry *e3 = active_cache[i + 1];
5b2fd956
SB
438 if (ce_stage(e2) == 2 &&
439 ce_stage(e3) == 3 &&
ac49f5ca 440 ce_same_name(e, e3) &&
5b2fd956 441 S_ISREG(e2->ce_mode) &&
ac49f5ca
MZ
442 S_ISREG(e3->ce_mode))
443 *type = THREE_STAGED;
444 }
445
446 /* Skip the entries with the same name */
447 while (i < active_nr && ce_same_name(e, active_cache[i]))
448 i++;
449 return i;
450}
451
4b68c2a0
JH
452/*
453 * Scan the index and find paths that have conflicts that rerere can
454 * handle, i.e. the ones that has both stages #2 and #3.
455 *
456 * NEEDSWORK: we do not record or replay a previous "resolve by
457 * deletion" for a delete-modify conflict, as that is inherently risky
458 * without knowing what modification is being discarded. The only
459 * safe case, i.e. both side doing the deletion and modification that
460 * are identical to the previous round, might want to be handled,
461 * though.
462 */
ac49f5ca
MZ
463static int find_conflict(struct string_list *conflict)
464{
465 int i;
466 if (read_cache() < 0)
467 return error("Could not read index");
468
469 for (i = 0; i < active_nr;) {
470 int conflict_type;
9c5e6c80 471 const struct cache_entry *e = active_cache[i];
ac49f5ca
MZ
472 i = check_one_conflict(i, &conflict_type);
473 if (conflict_type == THREE_STAGED)
474 string_list_insert(conflict, (const char *)e->name);
475 }
476 return 0;
477}
478
4b68c2a0
JH
479/*
480 * The merge_rr list is meant to hold outstanding conflicted paths
481 * that rerere could handle. Abuse the list by adding other types of
482 * entries to allow the caller to show "rerere remaining".
483 *
484 * - Conflicted paths that rerere does not handle are added
485 * - Conflicted paths that have been resolved are marked as such
486 * by storing RERERE_RESOLVED to .util field (where conflict ID
487 * is expected to be stored).
488 *
489 * Do *not* write MERGE_RR file out after calling this function.
490 *
491 * NEEDSWORK: we may want to fix the caller that implements "rerere
492 * remaining" to do this without abusing merge_rr.
493 */
ac49f5ca
MZ
494int rerere_remaining(struct string_list *merge_rr)
495{
496 int i;
497 if (read_cache() < 0)
498 return error("Could not read index");
499
500 for (i = 0; i < active_nr;) {
501 int conflict_type;
9c5e6c80 502 const struct cache_entry *e = active_cache[i];
ac49f5ca
MZ
503 i = check_one_conflict(i, &conflict_type);
504 if (conflict_type == PUNTED)
505 string_list_insert(merge_rr, (const char *)e->name);
506 else if (conflict_type == RESOLVED) {
507 struct string_list_item *it;
508 it = string_list_lookup(merge_rr, (const char *)e->name);
509 if (it != NULL) {
510 free(it->util);
511 it->util = RERERE_RESOLVED;
512 }
5b2fd956
SB
513 }
514 }
515 return 0;
516}
517
518static int merge(const char *name, const char *path)
519{
520 int ret;
689b8c29 521 mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
5b2fd956 522 mmbuffer_t result = {NULL, 0};
5b2fd956 523
90056966 524 if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
5b2fd956
SB
525 return 1;
526
90056966
SG
527 if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
528 read_mmfile(&base, rerere_path(name, "preimage")) ||
689b8c29
BW
529 read_mmfile(&other, rerere_path(name, "postimage"))) {
530 ret = 1;
531 goto out;
532 }
1e4cd68c 533 ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", NULL);
5b2fd956 534 if (!ret) {
7d7ff15b
SG
535 FILE *f;
536
537 if (utime(rerere_path(name, "postimage"), NULL) < 0)
538 warning("failed utime() on %s: %s",
539 rerere_path(name, "postimage"),
540 strerror(errno));
541 f = fopen(path, "w");
5b2fd956 542 if (!f)
47d32af2
AR
543 return error("Could not open %s: %s", path,
544 strerror(errno));
545 if (fwrite(result.ptr, result.size, 1, f) != 1)
546 error("Could not write %s: %s", path, strerror(errno));
547 if (fclose(f))
548 return error("Writing %s failed: %s", path,
549 strerror(errno));
5b2fd956
SB
550 }
551
689b8c29 552out:
5b2fd956
SB
553 free(cur.ptr);
554 free(base.ptr);
555 free(other.ptr);
556 free(result.ptr);
557
558 return ret;
559}
560
561static struct lock_file index_lock;
562
89ea9035 563static void update_paths(struct string_list *update)
5b2fd956
SB
564{
565 int i;
5b2fd956 566
89ea9035 567 hold_locked_index(&index_lock, 1);
5b2fd956
SB
568
569 for (i = 0; i < update->nr; i++) {
c455c87c 570 struct string_list_item *item = &update->items[i];
89ea9035
JN
571 if (add_file_to_cache(item->string, 0))
572 exit(128);
a14c7ab8
JH
573 fprintf(stderr, "Staged '%s' using previous resolution.\n",
574 item->string);
5b2fd956
SB
575 }
576
89ea9035 577 if (active_cache_changed) {
03b86647 578 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
5b2fd956 579 die("Unable to write new index file");
89ea9035 580 } else
5b2fd956 581 rollback_lock_file(&index_lock);
5b2fd956
SB
582}
583
c455c87c 584static int do_plain_rerere(struct string_list *rr, int fd)
5b2fd956 585{
183113a5
TF
586 struct string_list conflict = STRING_LIST_INIT_DUP;
587 struct string_list update = STRING_LIST_INIT_DUP;
5b2fd956
SB
588 int i;
589
590 find_conflict(&conflict);
591
592 /*
593 * MERGE_RR records paths with conflicts immediately after merge
594 * failed. Some of the conflicted paths might have been hand resolved
595 * in the working tree since then, but the initial run would catch all
596 * and register their preimages.
597 */
598
599 for (i = 0; i < conflict.nr; i++) {
c455c87c
JS
600 const char *path = conflict.items[i].string;
601 if (!string_list_has_string(rr, path)) {
5b2fd956
SB
602 unsigned char sha1[20];
603 char *hex;
604 int ret;
605 ret = handle_file(path, sha1, NULL);
606 if (ret < 1)
607 continue;
608 hex = xstrdup(sha1_to_hex(sha1));
78a395d3 609 string_list_insert(rr, path)->util = hex;
fd956338 610 if (mkdir_in_gitdir(git_path("rr-cache/%s", hex)))
ba19a808 611 continue;
90056966 612 handle_file(path, NULL, rerere_path(hex, "preimage"));
5b2fd956
SB
613 fprintf(stderr, "Recorded preimage for '%s'\n", path);
614 }
615 }
616
617 /*
618 * Now some of the paths that had conflicts earlier might have been
619 * hand resolved. Others may be similar to a conflict already that
620 * was resolved before.
621 */
622
623 for (i = 0; i < rr->nr; i++) {
624 int ret;
c455c87c 625 const char *path = rr->items[i].string;
5b2fd956
SB
626 const char *name = (const char *)rr->items[i].util;
627
90056966 628 if (has_rerere_resolution(name)) {
a14c7ab8
JH
629 if (merge(name, path))
630 continue;
631
632 if (rerere_autoupdate)
633 string_list_insert(&update, path);
634 else
635 fprintf(stderr,
636 "Resolved '%s' using previous resolution.\n",
637 path);
638 goto mark_resolved;
5b2fd956
SB
639 }
640
641 /* Let's see if we have resolved it. */
642 ret = handle_file(path, NULL, NULL);
643 if (ret)
644 continue;
645
646 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
90056966 647 copy_file(rerere_path(name, "postimage"), path, 0666);
5b2fd956 648 mark_resolved:
8d9b5a4a 649 free(rr->items[i].util);
5b2fd956
SB
650 rr->items[i].util = NULL;
651 }
652
653 if (update.nr)
654 update_paths(&update);
655
656 return write_rr(rr, fd);
657}
658
633e5ad3 659static void git_rerere_config(void)
5b2fd956 660{
633e5ad3
TA
661 git_config_get_bool("rerere.enabled", &rerere_enabled);
662 git_config_get_bool("rerere.autoupdate", &rerere_autoupdate);
663 git_config(git_default_config, NULL);
5b2fd956
SB
664}
665
666static int is_rerere_enabled(void)
667{
5b2fd956
SB
668 const char *rr_cache;
669 int rr_cache_exists;
670
671 if (!rerere_enabled)
672 return 0;
673
674 rr_cache = git_path("rr-cache");
90b4a71c 675 rr_cache_exists = is_directory(rr_cache);
5b2fd956
SB
676 if (rerere_enabled < 0)
677 return rr_cache_exists;
678
90a6464b 679 if (!rr_cache_exists && mkdir_in_gitdir(rr_cache))
5b2fd956
SB
680 die("Could not create directory %s", rr_cache);
681 return 1;
682}
683
cb6020bb 684int setup_rerere(struct string_list *merge_rr, int flags)
5b2fd956
SB
685{
686 int fd;
687
633e5ad3 688 git_rerere_config();
5b2fd956
SB
689 if (!is_rerere_enabled())
690 return -1;
691
cb6020bb
JH
692 if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
693 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
a4f34cbb 694 merge_rr_path = git_pathdup("MERGE_RR");
acd3b9ec
JH
695 fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
696 LOCK_DIE_ON_ERROR);
5b2fd956
SB
697 read_rr(merge_rr);
698 return fd;
699}
700
cb6020bb 701int rerere(int flags)
5b2fd956 702{
183113a5 703 struct string_list merge_rr = STRING_LIST_INIT_DUP;
5b2fd956
SB
704 int fd;
705
cb6020bb 706 fd = setup_rerere(&merge_rr, flags);
5b2fd956
SB
707 if (fd < 0)
708 return 0;
709 return do_plain_rerere(&merge_rr, fd);
710}
dea4562b
JH
711
712static int rerere_forget_one_path(const char *path, struct string_list *rr)
713{
714 const char *filename;
715 char *hex;
716 unsigned char sha1[20];
717 int ret;
8d9b5a4a 718 struct string_list_item *item;
dea4562b
JH
719
720 ret = handle_cache(path, sha1, NULL);
721 if (ret < 1)
722 return error("Could not parse conflict hunks in '%s'", path);
723 hex = xstrdup(sha1_to_hex(sha1));
724 filename = rerere_path(hex, "postimage");
725 if (unlink(filename))
726 return (errno == ENOENT
727 ? error("no remembered resolution for %s", path)
728 : error("cannot unlink %s: %s", filename, strerror(errno)));
729
730 handle_cache(path, sha1, rerere_path(hex, "preimage"));
731 fprintf(stderr, "Updated preimage for '%s'\n", path);
732
8d9b5a4a
JH
733 item = string_list_insert(rr, path);
734 free(item->util);
735 item->util = hex;
dea4562b
JH
736 fprintf(stderr, "Forgot resolution for %s\n", path);
737 return 0;
738}
739
01a10b0a 740int rerere_forget(struct pathspec *pathspec)
dea4562b
JH
741{
742 int i, fd;
183113a5
TF
743 struct string_list conflict = STRING_LIST_INIT_DUP;
744 struct string_list merge_rr = STRING_LIST_INIT_DUP;
dea4562b
JH
745
746 if (read_cache() < 0)
747 return error("Could not read index");
748
6751e047 749 fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
dea4562b
JH
750
751 unmerge_cache(pathspec);
752 find_conflict(&conflict);
753 for (i = 0; i < conflict.nr; i++) {
754 struct string_list_item *it = &conflict.items[i];
854b0959 755 if (!match_pathspec(pathspec, it->string,
ae8d0824 756 strlen(it->string), 0, NULL, 0))
dea4562b
JH
757 continue;
758 rerere_forget_one_path(it->string, &merge_rr);
759 }
760 return write_rr(&merge_rr, fd);
761}
0f891e7d
JH
762
763static time_t rerere_created_at(const char *name)
764{
765 struct stat st;
766 return stat(rerere_path(name, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
767}
768
769static time_t rerere_last_used_at(const char *name)
770{
771 struct stat st;
772 return stat(rerere_path(name, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
773}
774
775static void unlink_rr_item(const char *name)
776{
777 unlink(rerere_path(name, "thisimage"));
778 unlink(rerere_path(name, "preimage"));
779 unlink(rerere_path(name, "postimage"));
780 rmdir(git_path("rr-cache/%s", name));
781}
782
0f891e7d
JH
783void rerere_gc(struct string_list *rr)
784{
785 struct string_list to_remove = STRING_LIST_INIT_DUP;
786 DIR *dir;
787 struct dirent *e;
788 int i, cutoff;
789 time_t now = time(NULL), then;
633e5ad3
TA
790 int cutoff_noresolve = 15;
791 int cutoff_resolve = 60;
0f891e7d 792
633e5ad3
TA
793 git_config_get_int("gc.rerereresolved", &cutoff_resolve);
794 git_config_get_int("gc.rerereunresolved", &cutoff_noresolve);
795 git_config(git_default_config, NULL);
0f891e7d
JH
796 dir = opendir(git_path("rr-cache"));
797 if (!dir)
798 die_errno("unable to open rr-cache directory");
799 while ((e = readdir(dir))) {
800 if (is_dot_or_dotdot(e->d_name))
801 continue;
802
803 then = rerere_last_used_at(e->d_name);
804 if (then) {
633e5ad3 805 cutoff = cutoff_resolve;
0f891e7d
JH
806 } else {
807 then = rerere_created_at(e->d_name);
808 if (!then)
809 continue;
633e5ad3 810 cutoff = cutoff_noresolve;
0f891e7d
JH
811 }
812 if (then < now - cutoff * 86400)
813 string_list_append(&to_remove, e->d_name);
814 }
a9930e35 815 closedir(dir);
0f891e7d
JH
816 for (i = 0; i < to_remove.nr; i++)
817 unlink_rr_item(to_remove.items[i].string);
818 string_list_clear(&to_remove, 0);
819}
820
821void rerere_clear(struct string_list *merge_rr)
822{
823 int i;
824
825 for (i = 0; i < merge_rr->nr; i++) {
826 const char *name = (const char *)merge_rr->items[i].util;
827 if (!has_rerere_resolution(name))
828 unlink_rr_item(name);
829 }
830 unlink_or_warn(git_path("MERGE_RR"));
831}