rerere: replace strcpy with xsnprintf
[git/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
1d51eced 25static void free_rerere_id(struct string_list_item *item)
5b2fd956 26{
1d51eced
JH
27 free(item->util);
28}
29
30static const char *rerere_id_hex(const struct rerere_id *id)
31{
32 return id->hex;
33}
34
35const char *rerere_path(const struct rerere_id *id, const char *file)
36{
37 if (!file)
38 return git_path("rr-cache/%s", rerere_id_hex(id));
39
40 return git_path("rr-cache/%s/%s", rerere_id_hex(id), file);
5b2fd956
SB
41}
42
1d51eced 43static int has_rerere_resolution(const struct rerere_id *id)
5b2fd956
SB
44{
45 struct stat st;
1d51eced 46
18bb9934 47 return !stat(rerere_path(id, "postimage"), &st);
5b2fd956
SB
48}
49
1d51eced
JH
50static struct rerere_id *new_rerere_id_hex(char *hex)
51{
52 struct rerere_id *id = xmalloc(sizeof(*id));
f58316db 53 xsnprintf(id->hex, sizeof(id->hex), "%s", hex);
1d51eced
JH
54 return id;
55}
56
57static struct rerere_id *new_rerere_id(unsigned char *sha1)
58{
59 return new_rerere_id_hex(sha1_to_hex(sha1));
60}
61
4b68c2a0
JH
62/*
63 * $GIT_DIR/MERGE_RR file is a collection of records, each of which is
64 * "conflict ID", a HT and pathname, terminated with a NUL, and is
65 * used to keep track of the set of paths that "rerere" may need to
66 * work on (i.e. what is left by the previous invocation of "git
67 * rerere" during the current conflict resolution session).
68 */
c455c87c 69static void read_rr(struct string_list *rr)
5b2fd956 70{
f5800f6a 71 struct strbuf buf = STRBUF_INIT;
5b2fd956 72 FILE *in = fopen(merge_rr_path, "r");
f5800f6a 73
5b2fd956
SB
74 if (!in)
75 return;
f5800f6a
JH
76 while (!strbuf_getwholeline(&buf, in, '\0')) {
77 char *path;
78 unsigned char sha1[20];
1d51eced 79 struct rerere_id *id;
f5800f6a
JH
80
81 /* There has to be the hash, tab, path and then NUL */
82 if (buf.len < 42 || get_sha1_hex(buf.buf, sha1))
5b2fd956 83 die("corrupt MERGE_RR");
f5800f6a
JH
84
85 if (buf.buf[40] != '\t')
5b2fd956 86 die("corrupt MERGE_RR");
f5800f6a
JH
87 buf.buf[40] = '\0';
88 path = buf.buf + 41;
1d51eced
JH
89 id = new_rerere_id_hex(buf.buf);
90 string_list_insert(rr, path)->util = id;
5b2fd956 91 }
f5800f6a 92 strbuf_release(&buf);
5b2fd956
SB
93 fclose(in);
94}
95
96static struct lock_file write_lock;
97
c455c87c 98static int write_rr(struct string_list *rr, int out_fd)
5b2fd956
SB
99{
100 int i;
101 for (i = 0; i < rr->nr; i++) {
e2cb6a95 102 struct strbuf buf = STRBUF_INIT;
1d51eced 103 struct rerere_id *id;
e2cb6a95
JH
104
105 assert(rr->items[i].util != RERERE_RESOLVED);
1d51eced
JH
106
107 id = rr->items[i].util;
108 if (!id)
5b2fd956 109 continue;
e2cb6a95 110 strbuf_addf(&buf, "%s\t%s%c",
1d51eced 111 rerere_id_hex(id),
e2cb6a95
JH
112 rr->items[i].string, 0);
113 if (write_in_full(out_fd, buf.buf, buf.len) != buf.len)
5b2fd956 114 die("unable to write rerere record");
e2cb6a95
JH
115
116 strbuf_release(&buf);
5b2fd956
SB
117 }
118 if (commit_lock_file(&write_lock) != 0)
119 die("unable to write rerere record");
120 return 0;
121}
122
a96847cc
JH
123/*
124 * "rerere" interacts with conflicted file contents using this I/O
125 * abstraction. It reads a conflicted contents from one place via
126 * "getline()" method, and optionally can write it out after
127 * normalizing the conflicted hunks to the "output". Subclasses of
128 * rerere_io embed this structure at the beginning of their own
129 * rerere_io object.
130 */
131struct rerere_io {
132 int (*getline)(struct strbuf *, struct rerere_io *);
133 FILE *output;
134 int wrerror;
135 /* some more stuff */
136};
137
47d32af2
AR
138static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
139{
140 if (!count || *err)
141 return;
142 if (fwrite(p, count, 1, fp) != 1)
143 *err = errno;
144}
145
146static inline void ferr_puts(const char *s, FILE *fp, int *err)
147{
148 ferr_write(s, strlen(s), fp, err);
149}
150
27d6b085
JH
151static void rerere_io_putstr(const char *str, struct rerere_io *io)
152{
153 if (io->output)
154 ferr_puts(str, io->output, &io->wrerror);
155}
156
a96847cc
JH
157/*
158 * Write a conflict marker to io->output (if defined).
159 */
191f2417
JH
160static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
161{
162 char buf[64];
163
164 while (size) {
d3c2749d 165 if (size <= sizeof(buf) - 2) {
191f2417
JH
166 memset(buf, ch, size);
167 buf[size] = '\n';
168 buf[size + 1] = '\0';
169 size = 0;
170 } else {
171 int sz = sizeof(buf) - 1;
d3c2749d
JH
172
173 /*
174 * Make sure we will not write everything out
175 * in this round by leaving at least 1 byte
176 * for the next round, giving the next round
177 * a chance to add the terminating LF. Yuck.
178 */
191f2417
JH
179 if (size <= sz)
180 sz -= (sz - size) + 1;
181 memset(buf, ch, sz);
182 buf[sz] = '\0';
183 size -= sz;
184 }
185 rerere_io_putstr(buf, io);
186 }
187}
188
27d6b085
JH
189static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
190{
191 if (io->output)
192 ferr_write(mem, sz, io->output, &io->wrerror);
193}
194
a96847cc
JH
195/*
196 * Subclass of rerere_io that reads from an on-disk file
197 */
27d6b085
JH
198struct rerere_io_file {
199 struct rerere_io io;
200 FILE *input;
201};
202
a96847cc
JH
203/*
204 * ... and its getline() method implementation
205 */
27d6b085
JH
206static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
207{
208 struct rerere_io_file *io = (struct rerere_io_file *)io_;
209 return strbuf_getwholeline(sb, io->input, '\n');
210}
211
67711cdc
JH
212/*
213 * Require the exact number of conflict marker letters, no more, no
214 * less, followed by SP or any whitespace
215 * (including LF).
216 */
217static int is_cmarker(char *buf, int marker_char, int marker_size)
191f2417 218{
67711cdc
JH
219 int want_sp;
220
221 /*
222 * The beginning of our version and the end of their version
223 * always are labeled like "<<<<< ours" or ">>>>> theirs",
224 * hence we set want_sp for them. Note that the version from
225 * the common ancestor in diff3-style output is not always
226 * labelled (e.g. "||||| common" is often seen but "|||||"
227 * alone is also valid), so we do not set want_sp.
228 */
229 want_sp = (marker_char == '<') || (marker_char == '>');
230
191f2417
JH
231 while (marker_size--)
232 if (*buf++ != marker_char)
233 return 0;
234 if (want_sp && *buf != ' ')
235 return 0;
236 return isspace(*buf);
237}
238
cc899eca
JH
239/*
240 * Read contents a file with conflicts, normalize the conflicts
241 * by (1) discarding the common ancestor version in diff3-style,
242 * (2) reordering our side and their side so that whichever sorts
243 * alphabetically earlier comes before the other one, while
244 * computing the "conflict ID", which is just an SHA-1 hash of
245 * one side of the conflict, NUL, the other side of the conflict,
246 * and NUL concatenated together.
247 *
248 * Return the number of conflict hunks found.
249 *
250 * NEEDSWORK: the logic and theory of operation behind this conflict
251 * normalization may deserve to be documented somewhere, perhaps in
252 * Documentation/technical/rerere.txt.
253 */
191f2417 254static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
5b2fd956 255{
9126f009 256 git_SHA_CTX ctx;
cc58d7df
JH
257 int hunk_no = 0;
258 enum {
4b05548f 259 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL
cc58d7df 260 } hunk = RR_CONTEXT;
f285a2d7 261 struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
d58ee6db 262 struct strbuf buf = STRBUF_INIT;
5b2fd956
SB
263
264 if (sha1)
9126f009 265 git_SHA1_Init(&ctx);
5b2fd956 266
27d6b085 267 while (!io->getline(&buf, io)) {
67711cdc 268 if (is_cmarker(buf.buf, '<', marker_size)) {
cc58d7df 269 if (hunk != RR_CONTEXT)
5b2fd956 270 goto bad;
cc58d7df 271 hunk = RR_SIDE_1;
67711cdc 272 } else if (is_cmarker(buf.buf, '|', marker_size)) {
cc58d7df 273 if (hunk != RR_SIDE_1)
5b2fd956 274 goto bad;
387c9d49 275 hunk = RR_ORIGINAL;
67711cdc 276 } else if (is_cmarker(buf.buf, '=', marker_size)) {
387c9d49 277 if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
5b2fd956 278 goto bad;
cc58d7df 279 hunk = RR_SIDE_2;
67711cdc 280 } else if (is_cmarker(buf.buf, '>', marker_size)) {
cc58d7df 281 if (hunk != RR_SIDE_2)
5b2fd956
SB
282 goto bad;
283 if (strbuf_cmp(&one, &two) > 0)
284 strbuf_swap(&one, &two);
285 hunk_no++;
cc58d7df 286 hunk = RR_CONTEXT;
191f2417 287 rerere_io_putconflict('<', marker_size, io);
27d6b085 288 rerere_io_putmem(one.buf, one.len, io);
191f2417 289 rerere_io_putconflict('=', marker_size, io);
27d6b085 290 rerere_io_putmem(two.buf, two.len, io);
191f2417 291 rerere_io_putconflict('>', marker_size, io);
5b2fd956 292 if (sha1) {
9126f009 293 git_SHA1_Update(&ctx, one.buf ? one.buf : "",
5b2fd956 294 one.len + 1);
9126f009 295 git_SHA1_Update(&ctx, two.buf ? two.buf : "",
5b2fd956
SB
296 two.len + 1);
297 }
298 strbuf_reset(&one);
299 strbuf_reset(&two);
cc58d7df 300 } else if (hunk == RR_SIDE_1)
e992d1eb 301 strbuf_addbuf(&one, &buf);
387c9d49
JH
302 else if (hunk == RR_ORIGINAL)
303 ; /* discard */
cc58d7df 304 else if (hunk == RR_SIDE_2)
e992d1eb 305 strbuf_addbuf(&two, &buf);
27d6b085
JH
306 else
307 rerere_io_putstr(buf.buf, io);
5b2fd956
SB
308 continue;
309 bad:
310 hunk = 99; /* force error exit */
311 break;
312 }
313 strbuf_release(&one);
314 strbuf_release(&two);
d58ee6db 315 strbuf_release(&buf);
5b2fd956 316
5b2fd956 317 if (sha1)
9126f009 318 git_SHA1_Final(sha1, &ctx);
27d6b085
JH
319 if (hunk != RR_CONTEXT)
320 return -1;
321 return hunk_no;
322}
323
cc899eca
JH
324/*
325 * Scan the path for conflicts, do the "handle_path()" thing above, and
326 * return the number of conflict hunks found.
327 */
27d6b085
JH
328static int handle_file(const char *path, unsigned char *sha1, const char *output)
329{
330 int hunk_no = 0;
331 struct rerere_io_file io;
8588567c 332 int marker_size = ll_merge_marker_size(path);
27d6b085
JH
333
334 memset(&io, 0, sizeof(io));
335 io.io.getline = rerere_file_getline;
336 io.input = fopen(path, "r");
337 io.io.wrerror = 0;
338 if (!io.input)
339 return error("Could not open %s", path);
340
341 if (output) {
342 io.io.output = fopen(output, "w");
343 if (!io.io.output) {
344 fclose(io.input);
345 return error("Could not write %s", output);
346 }
347 }
348
191f2417 349 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
27d6b085
JH
350
351 fclose(io.input);
352 if (io.io.wrerror)
353 error("There were errors while writing %s (%s)",
354 path, strerror(io.io.wrerror));
355 if (io.io.output && fclose(io.io.output))
356 io.io.wrerror = error("Failed to flush %s: %s",
357 path, strerror(errno));
358
359 if (hunk_no < 0) {
5b2fd956 360 if (output)
691f1a28 361 unlink_or_warn(output);
5b2fd956
SB
362 return error("Could not parse conflict hunks in %s", path);
363 }
27d6b085 364 if (io.io.wrerror)
47d32af2 365 return -1;
5b2fd956
SB
366 return hunk_no;
367}
368
a96847cc
JH
369/*
370 * Subclass of rerere_io that reads from an in-core buffer that is a
371 * strbuf
372 */
dea4562b
JH
373struct rerere_io_mem {
374 struct rerere_io io;
375 struct strbuf input;
376};
377
a96847cc
JH
378/*
379 * ... and its getline() method implementation
380 */
dea4562b
JH
381static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
382{
383 struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
384 char *ep;
385 size_t len;
386
387 strbuf_release(sb);
388 if (!io->input.len)
389 return -1;
53d8afaf
JS
390 ep = memchr(io->input.buf, '\n', io->input.len);
391 if (!ep)
392 ep = io->input.buf + io->input.len;
393 else if (*ep == '\n')
dea4562b
JH
394 ep++;
395 len = ep - io->input.buf;
396 strbuf_add(sb, io->input.buf, len);
397 strbuf_remove(&io->input, 0, len);
398 return 0;
399}
400
401static int handle_cache(const char *path, unsigned char *sha1, const char *output)
402{
b9e31f59 403 mmfile_t mmfile[3] = {{NULL}};
dea4562b 404 mmbuffer_t result = {NULL, 0};
9c5e6c80 405 const struct cache_entry *ce;
dea4562b
JH
406 int pos, len, i, hunk_no;
407 struct rerere_io_mem io;
8588567c 408 int marker_size = ll_merge_marker_size(path);
dea4562b
JH
409
410 /*
411 * Reproduce the conflicted merge in-core
412 */
413 len = strlen(path);
414 pos = cache_name_pos(path, len);
415 if (0 <= pos)
47d32af2 416 return -1;
dea4562b
JH
417 pos = -pos - 1;
418
74444d4e 419 while (pos < active_nr) {
dea4562b
JH
420 enum object_type type;
421 unsigned long size;
422
dea4562b 423 ce = active_cache[pos++];
b9e31f59 424 if (ce_namelen(ce) != len || memcmp(ce->name, path, len))
74444d4e
JH
425 break;
426 i = ce_stage(ce) - 1;
7d4053b6
JH
427 if (!mmfile[i].ptr) {
428 mmfile[i].ptr = read_sha1_file(ce->sha1, &type, &size);
429 mmfile[i].size = size;
430 }
dea4562b 431 }
74444d4e 432 for (i = 0; i < 3; i++)
dea4562b
JH
433 if (!mmfile[i].ptr && !mmfile[i].size)
434 mmfile[i].ptr = xstrdup("");
74444d4e 435
18b037a5
JN
436 /*
437 * NEEDSWORK: handle conflicts from merges with
438 * merge.renormalize set, too
439 */
f01de62e 440 ll_merge(&result, path, &mmfile[0], NULL,
dea4562b 441 &mmfile[1], "ours",
712516bc 442 &mmfile[2], "theirs", NULL);
dea4562b
JH
443 for (i = 0; i < 3; i++)
444 free(mmfile[i].ptr);
445
af86debc 446 memset(&io, 0, sizeof(io));
dea4562b
JH
447 io.io.getline = rerere_mem_getline;
448 if (output)
449 io.io.output = fopen(output, "w");
450 else
451 io.io.output = NULL;
452 strbuf_init(&io.input, 0);
453 strbuf_attach(&io.input, result.ptr, result.size, result.size);
454
963ec003
JH
455 /*
456 * Grab the conflict ID and optionally write the original
457 * contents with conflict markers out.
458 */
191f2417 459 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
dea4562b
JH
460 strbuf_release(&io.input);
461 if (io.io.output)
462 fclose(io.io.output);
5b2fd956
SB
463 return hunk_no;
464}
465
4b68c2a0
JH
466/*
467 * Look at a cache entry at "i" and see if it is not conflicting,
468 * conflicting and we are willing to handle, or conflicting and
469 * we are unable to handle, and return the determination in *type.
470 * Return the cache index to be looked at next, by skipping the
471 * stages we have already looked at in this invocation of this
472 * function.
473 */
ac49f5ca 474static int check_one_conflict(int i, int *type)
5b2fd956 475{
9c5e6c80 476 const struct cache_entry *e = active_cache[i];
ac49f5ca
MZ
477
478 if (!ce_stage(e)) {
479 *type = RESOLVED;
480 return i + 1;
481 }
482
483 *type = PUNTED;
5eda906b 484 while (ce_stage(active_cache[i]) == 1)
fb70a06d 485 i++;
ac49f5ca
MZ
486
487 /* Only handle regular files with both stages #2 and #3 */
488 if (i + 1 < active_nr) {
9c5e6c80
NTND
489 const struct cache_entry *e2 = active_cache[i];
490 const struct cache_entry *e3 = active_cache[i + 1];
5b2fd956
SB
491 if (ce_stage(e2) == 2 &&
492 ce_stage(e3) == 3 &&
ac49f5ca 493 ce_same_name(e, e3) &&
5b2fd956 494 S_ISREG(e2->ce_mode) &&
ac49f5ca
MZ
495 S_ISREG(e3->ce_mode))
496 *type = THREE_STAGED;
497 }
498
499 /* Skip the entries with the same name */
500 while (i < active_nr && ce_same_name(e, active_cache[i]))
501 i++;
502 return i;
503}
504
4b68c2a0
JH
505/*
506 * Scan the index and find paths that have conflicts that rerere can
507 * handle, i.e. the ones that has both stages #2 and #3.
508 *
509 * NEEDSWORK: we do not record or replay a previous "resolve by
510 * deletion" for a delete-modify conflict, as that is inherently risky
511 * without knowing what modification is being discarded. The only
512 * safe case, i.e. both side doing the deletion and modification that
513 * are identical to the previous round, might want to be handled,
514 * though.
515 */
ac49f5ca
MZ
516static int find_conflict(struct string_list *conflict)
517{
518 int i;
519 if (read_cache() < 0)
520 return error("Could not read index");
521
522 for (i = 0; i < active_nr;) {
523 int conflict_type;
9c5e6c80 524 const struct cache_entry *e = active_cache[i];
ac49f5ca
MZ
525 i = check_one_conflict(i, &conflict_type);
526 if (conflict_type == THREE_STAGED)
527 string_list_insert(conflict, (const char *)e->name);
528 }
529 return 0;
530}
531
4b68c2a0
JH
532/*
533 * The merge_rr list is meant to hold outstanding conflicted paths
534 * that rerere could handle. Abuse the list by adding other types of
535 * entries to allow the caller to show "rerere remaining".
536 *
537 * - Conflicted paths that rerere does not handle are added
538 * - Conflicted paths that have been resolved are marked as such
539 * by storing RERERE_RESOLVED to .util field (where conflict ID
540 * is expected to be stored).
541 *
542 * Do *not* write MERGE_RR file out after calling this function.
543 *
544 * NEEDSWORK: we may want to fix the caller that implements "rerere
545 * remaining" to do this without abusing merge_rr.
546 */
ac49f5ca
MZ
547int rerere_remaining(struct string_list *merge_rr)
548{
549 int i;
550 if (read_cache() < 0)
551 return error("Could not read index");
552
553 for (i = 0; i < active_nr;) {
554 int conflict_type;
9c5e6c80 555 const struct cache_entry *e = active_cache[i];
ac49f5ca
MZ
556 i = check_one_conflict(i, &conflict_type);
557 if (conflict_type == PUNTED)
558 string_list_insert(merge_rr, (const char *)e->name);
559 else if (conflict_type == RESOLVED) {
560 struct string_list_item *it;
561 it = string_list_lookup(merge_rr, (const char *)e->name);
562 if (it != NULL) {
1d51eced 563 free_rerere_id(it);
ac49f5ca
MZ
564 it->util = RERERE_RESOLVED;
565 }
5b2fd956
SB
566 }
567 }
568 return 0;
569}
570
cc899eca 571/*
18bb9934 572 * Find the conflict identified by "id"; the change between its
cc899eca
JH
573 * "preimage" (i.e. a previous contents with conflict markers) and its
574 * "postimage" (i.e. the corresponding contents with conflicts
575 * resolved) may apply cleanly to the contents stored in "path", i.e.
576 * the conflict this time around.
577 *
578 * Returns 0 for successful replay of recorded resolution, or non-zero
579 * for failure.
580 */
1d51eced 581static int merge(const struct rerere_id *id, const char *path)
5b2fd956 582{
15ed07d5 583 FILE *f;
5b2fd956 584 int ret;
689b8c29 585 mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
5b2fd956 586 mmbuffer_t result = {NULL, 0};
5b2fd956 587
cc899eca
JH
588 /*
589 * Normalize the conflicts in path and write it out to
590 * "thisimage" temporary file.
591 */
15ed07d5
JH
592 if (handle_file(path, NULL, rerere_path(id, "thisimage")) < 0) {
593 ret = 1;
594 goto out;
595 }
5b2fd956 596
18bb9934
JH
597 if (read_mmfile(&cur, rerere_path(id, "thisimage")) ||
598 read_mmfile(&base, rerere_path(id, "preimage")) ||
599 read_mmfile(&other, rerere_path(id, "postimage"))) {
689b8c29
BW
600 ret = 1;
601 goto out;
602 }
cc899eca
JH
603
604 /*
605 * A three-way merge. Note that this honors user-customizable
606 * low-level merge driver settings.
607 */
1e4cd68c 608 ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", NULL);
15ed07d5
JH
609 if (ret)
610 goto out;
611
612 /*
613 * A successful replay of recorded resolution.
614 * Mark that "postimage" was used to help gc.
615 */
616 if (utime(rerere_path(id, "postimage"), NULL) < 0)
617 warning("failed utime() on %s: %s",
618 rerere_path(id, "postimage"),
619 strerror(errno));
620
621 /* Update "path" with the resolution */
622 f = fopen(path, "w");
623 if (!f)
624 return error("Could not open %s: %s", path,
625 strerror(errno));
626 if (fwrite(result.ptr, result.size, 1, f) != 1)
627 error("Could not write %s: %s", path, strerror(errno));
628 if (fclose(f))
629 return error("Writing %s failed: %s", path,
630 strerror(errno));
5b2fd956 631
689b8c29 632out:
5b2fd956
SB
633 free(cur.ptr);
634 free(base.ptr);
635 free(other.ptr);
636 free(result.ptr);
637
638 return ret;
639}
640
641static struct lock_file index_lock;
642
89ea9035 643static void update_paths(struct string_list *update)
5b2fd956
SB
644{
645 int i;
5b2fd956 646
89ea9035 647 hold_locked_index(&index_lock, 1);
5b2fd956
SB
648
649 for (i = 0; i < update->nr; i++) {
c455c87c 650 struct string_list_item *item = &update->items[i];
89ea9035
JN
651 if (add_file_to_cache(item->string, 0))
652 exit(128);
a14c7ab8
JH
653 fprintf(stderr, "Staged '%s' using previous resolution.\n",
654 item->string);
5b2fd956
SB
655 }
656
89ea9035 657 if (active_cache_changed) {
03b86647 658 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
5b2fd956 659 die("Unable to write new index file");
89ea9035 660 } else
5b2fd956 661 rollback_lock_file(&index_lock);
5b2fd956
SB
662}
663
8e7768b2
JH
664/*
665 * The path indicated by rr_item may still have conflict for which we
666 * have a recorded resolution, in which case replay it and optionally
667 * update it. Or it may have been resolved by the user and we may
668 * only have the preimage for that conflict, in which case the result
669 * needs to be recorded as a resolution in a postimage file.
670 */
671static void do_rerere_one_path(struct string_list_item *rr_item,
672 struct string_list *update)
673{
674 const char *path = rr_item->string;
1d51eced 675 const struct rerere_id *id = rr_item->util;
8e7768b2
JH
676
677 /* Is there a recorded resolution we could attempt to apply? */
18bb9934
JH
678 if (has_rerere_resolution(id)) {
679 if (merge(id, path))
8e7768b2
JH
680 return; /* failed to replay */
681
682 if (rerere_autoupdate)
683 string_list_insert(update, path);
684 else
685 fprintf(stderr,
686 "Resolved '%s' using previous resolution.\n",
687 path);
925d73c4
JH
688 } else if (!handle_file(path, NULL, NULL)) {
689 /* The user has resolved it. */
18bb9934 690 copy_file(rerere_path(id, "postimage"), path, 0666);
925d73c4
JH
691 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
692 } else {
693 return;
8e7768b2 694 }
1d51eced 695 free_rerere_id(rr_item);
8e7768b2
JH
696 rr_item->util = NULL;
697}
698
c455c87c 699static int do_plain_rerere(struct string_list *rr, int fd)
5b2fd956 700{
183113a5
TF
701 struct string_list conflict = STRING_LIST_INIT_DUP;
702 struct string_list update = STRING_LIST_INIT_DUP;
5b2fd956
SB
703 int i;
704
705 find_conflict(&conflict);
706
707 /*
cc899eca
JH
708 * MERGE_RR records paths with conflicts immediately after
709 * merge failed. Some of the conflicted paths might have been
710 * hand resolved in the working tree since then, but the
711 * initial run would catch all and register their preimages.
5b2fd956 712 */
5b2fd956 713 for (i = 0; i < conflict.nr; i++) {
1d51eced 714 struct rerere_id *id;
c7a25d37 715 unsigned char sha1[20];
c455c87c 716 const char *path = conflict.items[i].string;
1d51eced 717 int ret;
cc899eca 718
c7a25d37
JH
719 if (string_list_has_string(rr, path))
720 continue;
cc899eca 721
c7a25d37
JH
722 /*
723 * Ask handle_file() to scan and assign a
724 * conflict ID. No need to write anything out
725 * yet.
726 */
727 ret = handle_file(path, sha1, NULL);
728 if (ret < 1)
729 continue;
1d51eced
JH
730
731 id = new_rerere_id(sha1);
18bb9934 732 string_list_insert(rr, path)->util = id;
cc899eca 733
c7a25d37
JH
734 /*
735 * If the directory does not exist, create
736 * it. mkdir_in_gitdir() will fail with
737 * EEXIST if there already is one.
738 *
739 * NEEDSWORK: make sure "gc" does not remove
740 * preimage without removing the directory.
741 */
1d51eced 742 if (mkdir_in_gitdir(rerere_path(id, NULL)))
c7a25d37
JH
743 continue;
744
745 /*
746 * We are the first to encounter this
747 * conflict. Ask handle_file() to write the
748 * normalized contents to the "preimage" file.
749 */
18bb9934 750 handle_file(path, NULL, rerere_path(id, "preimage"));
c7a25d37 751 fprintf(stderr, "Recorded preimage for '%s'\n", path);
5b2fd956
SB
752 }
753
8e7768b2
JH
754 for (i = 0; i < rr->nr; i++)
755 do_rerere_one_path(&rr->items[i], &update);
5b2fd956
SB
756
757 if (update.nr)
758 update_paths(&update);
759
760 return write_rr(rr, fd);
761}
762
633e5ad3 763static void git_rerere_config(void)
5b2fd956 764{
633e5ad3
TA
765 git_config_get_bool("rerere.enabled", &rerere_enabled);
766 git_config_get_bool("rerere.autoupdate", &rerere_autoupdate);
767 git_config(git_default_config, NULL);
5b2fd956
SB
768}
769
770static int is_rerere_enabled(void)
771{
5b2fd956
SB
772 const char *rr_cache;
773 int rr_cache_exists;
774
775 if (!rerere_enabled)
776 return 0;
777
778 rr_cache = git_path("rr-cache");
90b4a71c 779 rr_cache_exists = is_directory(rr_cache);
5b2fd956
SB
780 if (rerere_enabled < 0)
781 return rr_cache_exists;
782
90a6464b 783 if (!rr_cache_exists && mkdir_in_gitdir(rr_cache))
5b2fd956
SB
784 die("Could not create directory %s", rr_cache);
785 return 1;
786}
787
cb6020bb 788int setup_rerere(struct string_list *merge_rr, int flags)
5b2fd956
SB
789{
790 int fd;
791
633e5ad3 792 git_rerere_config();
5b2fd956
SB
793 if (!is_rerere_enabled())
794 return -1;
795
cb6020bb
JH
796 if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
797 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
a4f34cbb 798 merge_rr_path = git_pathdup("MERGE_RR");
acd3b9ec
JH
799 fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
800 LOCK_DIE_ON_ERROR);
5b2fd956
SB
801 read_rr(merge_rr);
802 return fd;
803}
804
cc899eca
JH
805/*
806 * The main entry point that is called internally from codepaths that
807 * perform mergy operations, possibly leaving conflicted index entries
808 * and working tree files.
809 */
cb6020bb 810int rerere(int flags)
5b2fd956 811{
183113a5 812 struct string_list merge_rr = STRING_LIST_INIT_DUP;
5b2fd956
SB
813 int fd;
814
cb6020bb 815 fd = setup_rerere(&merge_rr, flags);
5b2fd956
SB
816 if (fd < 0)
817 return 0;
818 return do_plain_rerere(&merge_rr, fd);
819}
dea4562b
JH
820
821static int rerere_forget_one_path(const char *path, struct string_list *rr)
822{
823 const char *filename;
1d51eced 824 struct rerere_id *id;
dea4562b
JH
825 unsigned char sha1[20];
826 int ret;
8d9b5a4a 827 struct string_list_item *item;
dea4562b 828
963ec003
JH
829 /*
830 * Recreate the original conflict from the stages in the
831 * index and compute the conflict ID
832 */
dea4562b
JH
833 ret = handle_cache(path, sha1, NULL);
834 if (ret < 1)
835 return error("Could not parse conflict hunks in '%s'", path);
963ec003
JH
836
837 /* Nuke the recorded resolution for the conflict */
1d51eced 838 id = new_rerere_id(sha1);
18bb9934 839 filename = rerere_path(id, "postimage");
dea4562b
JH
840 if (unlink(filename))
841 return (errno == ENOENT
842 ? error("no remembered resolution for %s", path)
843 : error("cannot unlink %s: %s", filename, strerror(errno)));
844
963ec003
JH
845 /*
846 * Update the preimage so that the user can resolve the
847 * conflict in the working tree, run us again to record
848 * the postimage.
849 */
18bb9934 850 handle_cache(path, sha1, rerere_path(id, "preimage"));
dea4562b
JH
851 fprintf(stderr, "Updated preimage for '%s'\n", path);
852
963ec003
JH
853 /*
854 * And remember that we can record resolution for this
855 * conflict when the user is done.
856 */
8d9b5a4a 857 item = string_list_insert(rr, path);
1d51eced 858 free_rerere_id(item);
18bb9934 859 item->util = id;
dea4562b
JH
860 fprintf(stderr, "Forgot resolution for %s\n", path);
861 return 0;
862}
863
01a10b0a 864int rerere_forget(struct pathspec *pathspec)
dea4562b
JH
865{
866 int i, fd;
183113a5
TF
867 struct string_list conflict = STRING_LIST_INIT_DUP;
868 struct string_list merge_rr = STRING_LIST_INIT_DUP;
dea4562b
JH
869
870 if (read_cache() < 0)
871 return error("Could not read index");
872
6751e047 873 fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
dea4562b 874
963ec003
JH
875 /*
876 * The paths may have been resolved (incorrectly);
877 * recover the original conflicted state and then
878 * find the conflicted paths.
879 */
dea4562b
JH
880 unmerge_cache(pathspec);
881 find_conflict(&conflict);
882 for (i = 0; i < conflict.nr; i++) {
883 struct string_list_item *it = &conflict.items[i];
854b0959 884 if (!match_pathspec(pathspec, it->string,
ae8d0824 885 strlen(it->string), 0, NULL, 0))
dea4562b
JH
886 continue;
887 rerere_forget_one_path(it->string, &merge_rr);
888 }
889 return write_rr(&merge_rr, fd);
890}
0f891e7d 891
e828de82
JH
892/*
893 * Garbage collection support
894 */
1d51eced
JH
895
896/*
897 * Note that this is not reentrant but is used only one-at-a-time
898 * so it does not matter right now.
899 */
900static struct rerere_id *dirname_to_id(const char *name)
901{
902 static struct rerere_id id;
f58316db 903 xsnprintf(id.hex, sizeof(id.hex), "%s", name);
1d51eced
JH
904 return &id;
905}
906
907static time_t rerere_created_at(const char *dir_name)
0f891e7d
JH
908{
909 struct stat st;
1d51eced
JH
910 struct rerere_id *id = dirname_to_id(dir_name);
911
18bb9934 912 return stat(rerere_path(id, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
0f891e7d
JH
913}
914
1d51eced 915static time_t rerere_last_used_at(const char *dir_name)
0f891e7d
JH
916{
917 struct stat st;
1d51eced
JH
918 struct rerere_id *id = dirname_to_id(dir_name);
919
18bb9934 920 return stat(rerere_path(id, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
0f891e7d
JH
921}
922
e828de82
JH
923/*
924 * Remove the recorded resolution for a given conflict ID
925 */
1d51eced 926static void unlink_rr_item(struct rerere_id *id)
0f891e7d 927{
18bb9934
JH
928 unlink(rerere_path(id, "thisimage"));
929 unlink(rerere_path(id, "preimage"));
930 unlink(rerere_path(id, "postimage"));
e828de82
JH
931 /*
932 * NEEDSWORK: what if this rmdir() fails? Wouldn't we then
933 * assume that we already have preimage recorded in
934 * do_plain_rerere()?
935 */
1d51eced 936 rmdir(rerere_path(id, NULL));
0f891e7d
JH
937}
938
0f891e7d
JH
939void rerere_gc(struct string_list *rr)
940{
941 struct string_list to_remove = STRING_LIST_INIT_DUP;
942 DIR *dir;
943 struct dirent *e;
944 int i, cutoff;
945 time_t now = time(NULL), then;
633e5ad3
TA
946 int cutoff_noresolve = 15;
947 int cutoff_resolve = 60;
0f891e7d 948
633e5ad3
TA
949 git_config_get_int("gc.rerereresolved", &cutoff_resolve);
950 git_config_get_int("gc.rerereunresolved", &cutoff_noresolve);
951 git_config(git_default_config, NULL);
0f891e7d
JH
952 dir = opendir(git_path("rr-cache"));
953 if (!dir)
954 die_errno("unable to open rr-cache directory");
e828de82 955 /* Collect stale conflict IDs ... */
0f891e7d
JH
956 while ((e = readdir(dir))) {
957 if (is_dot_or_dotdot(e->d_name))
958 continue;
959
960 then = rerere_last_used_at(e->d_name);
961 if (then) {
633e5ad3 962 cutoff = cutoff_resolve;
0f891e7d
JH
963 } else {
964 then = rerere_created_at(e->d_name);
965 if (!then)
966 continue;
633e5ad3 967 cutoff = cutoff_noresolve;
0f891e7d
JH
968 }
969 if (then < now - cutoff * 86400)
970 string_list_append(&to_remove, e->d_name);
971 }
a9930e35 972 closedir(dir);
e828de82 973 /* ... and then remove them one-by-one */
0f891e7d 974 for (i = 0; i < to_remove.nr; i++)
1d51eced 975 unlink_rr_item(dirname_to_id(to_remove.items[i].string));
0f891e7d
JH
976 string_list_clear(&to_remove, 0);
977}
978
e828de82
JH
979/*
980 * During a conflict resolution, after "rerere" recorded the
981 * preimages, abandon them if the user did not resolve them or
982 * record their resolutions. And drop $GIT_DIR/MERGE_RR.
983 *
984 * NEEDSWORK: shouldn't we be calling this from "reset --hard"?
985 */
0f891e7d
JH
986void rerere_clear(struct string_list *merge_rr)
987{
988 int i;
989
990 for (i = 0; i < merge_rr->nr; i++) {
1d51eced 991 struct rerere_id *id = merge_rr->items[i].util;
18bb9934
JH
992 if (!has_rerere_resolution(id))
993 unlink_rr_item(id);
0f891e7d
JH
994 }
995 unlink_or_warn(git_path("MERGE_RR"));
996}