Merge branch 'jp/string-list-api-cleanup'
[git/git.git] / rerere.c
1 #include "cache.h"
2 #include "string-list.h"
3 #include "rerere.h"
4 #include "xdiff-interface.h"
5 #include "dir.h"
6 #include "resolve-undo.h"
7 #include "ll-merge.h"
8 #include "attr.h"
9
10 /* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
11 static int rerere_enabled = -1;
12
13 /* automatically update cleanly resolved paths to the index */
14 static int rerere_autoupdate;
15
16 static char *merge_rr_path;
17
18 const char *rerere_path(const char *hex, const char *file)
19 {
20 return git_path("rr-cache/%s/%s", hex, file);
21 }
22
23 int has_rerere_resolution(const char *hex)
24 {
25 struct stat st;
26 return !stat(rerere_path(hex, "postimage"), &st);
27 }
28
29 static void read_rr(struct string_list *rr)
30 {
31 unsigned char sha1[20];
32 char buf[PATH_MAX];
33 FILE *in = fopen(merge_rr_path, "r");
34 if (!in)
35 return;
36 while (fread(buf, 40, 1, in) == 1) {
37 int i;
38 char *name;
39 if (get_sha1_hex(buf, sha1))
40 die("corrupt MERGE_RR");
41 buf[40] = '\0';
42 name = xstrdup(buf);
43 if (fgetc(in) != '\t')
44 die("corrupt MERGE_RR");
45 for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
46 ; /* do nothing */
47 if (i == sizeof(buf))
48 die("filename too long");
49 string_list_insert(rr, buf)->util = name;
50 }
51 fclose(in);
52 }
53
54 static struct lock_file write_lock;
55
56 static int write_rr(struct string_list *rr, int out_fd)
57 {
58 int i;
59 for (i = 0; i < rr->nr; i++) {
60 const char *path;
61 int length;
62 if (!rr->items[i].util)
63 continue;
64 path = rr->items[i].string;
65 length = strlen(path) + 1;
66 if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
67 write_str_in_full(out_fd, "\t") != 1 ||
68 write_in_full(out_fd, path, length) != length)
69 die("unable to write rerere record");
70 }
71 if (commit_lock_file(&write_lock) != 0)
72 die("unable to write rerere record");
73 return 0;
74 }
75
76 static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
77 {
78 if (!count || *err)
79 return;
80 if (fwrite(p, count, 1, fp) != 1)
81 *err = errno;
82 }
83
84 static inline void ferr_puts(const char *s, FILE *fp, int *err)
85 {
86 ferr_write(s, strlen(s), fp, err);
87 }
88
89 struct rerere_io {
90 int (*getline)(struct strbuf *, struct rerere_io *);
91 FILE *output;
92 int wrerror;
93 /* some more stuff */
94 };
95
96 static void rerere_io_putstr(const char *str, struct rerere_io *io)
97 {
98 if (io->output)
99 ferr_puts(str, io->output, &io->wrerror);
100 }
101
102 static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
103 {
104 char buf[64];
105
106 while (size) {
107 if (size < sizeof(buf) - 2) {
108 memset(buf, ch, size);
109 buf[size] = '\n';
110 buf[size + 1] = '\0';
111 size = 0;
112 } else {
113 int sz = sizeof(buf) - 1;
114 if (size <= sz)
115 sz -= (sz - size) + 1;
116 memset(buf, ch, sz);
117 buf[sz] = '\0';
118 size -= sz;
119 }
120 rerere_io_putstr(buf, io);
121 }
122 }
123
124 static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
125 {
126 if (io->output)
127 ferr_write(mem, sz, io->output, &io->wrerror);
128 }
129
130 struct rerere_io_file {
131 struct rerere_io io;
132 FILE *input;
133 };
134
135 static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
136 {
137 struct rerere_io_file *io = (struct rerere_io_file *)io_;
138 return strbuf_getwholeline(sb, io->input, '\n');
139 }
140
141 static int is_cmarker(char *buf, int marker_char, int marker_size, int want_sp)
142 {
143 while (marker_size--)
144 if (*buf++ != marker_char)
145 return 0;
146 if (want_sp && *buf != ' ')
147 return 0;
148 return isspace(*buf);
149 }
150
151 static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
152 {
153 git_SHA_CTX ctx;
154 int hunk_no = 0;
155 enum {
156 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL
157 } hunk = RR_CONTEXT;
158 struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
159 struct strbuf buf = STRBUF_INIT;
160
161 if (sha1)
162 git_SHA1_Init(&ctx);
163
164 while (!io->getline(&buf, io)) {
165 if (is_cmarker(buf.buf, '<', marker_size, 1)) {
166 if (hunk != RR_CONTEXT)
167 goto bad;
168 hunk = RR_SIDE_1;
169 } else if (is_cmarker(buf.buf, '|', marker_size, 0)) {
170 if (hunk != RR_SIDE_1)
171 goto bad;
172 hunk = RR_ORIGINAL;
173 } else if (is_cmarker(buf.buf, '=', marker_size, 0)) {
174 if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
175 goto bad;
176 hunk = RR_SIDE_2;
177 } else if (is_cmarker(buf.buf, '>', marker_size, 1)) {
178 if (hunk != RR_SIDE_2)
179 goto bad;
180 if (strbuf_cmp(&one, &two) > 0)
181 strbuf_swap(&one, &two);
182 hunk_no++;
183 hunk = RR_CONTEXT;
184 rerere_io_putconflict('<', marker_size, io);
185 rerere_io_putmem(one.buf, one.len, io);
186 rerere_io_putconflict('=', marker_size, io);
187 rerere_io_putmem(two.buf, two.len, io);
188 rerere_io_putconflict('>', marker_size, io);
189 if (sha1) {
190 git_SHA1_Update(&ctx, one.buf ? one.buf : "",
191 one.len + 1);
192 git_SHA1_Update(&ctx, two.buf ? two.buf : "",
193 two.len + 1);
194 }
195 strbuf_reset(&one);
196 strbuf_reset(&two);
197 } else if (hunk == RR_SIDE_1)
198 strbuf_addstr(&one, buf.buf);
199 else if (hunk == RR_ORIGINAL)
200 ; /* discard */
201 else if (hunk == RR_SIDE_2)
202 strbuf_addstr(&two, buf.buf);
203 else
204 rerere_io_putstr(buf.buf, io);
205 continue;
206 bad:
207 hunk = 99; /* force error exit */
208 break;
209 }
210 strbuf_release(&one);
211 strbuf_release(&two);
212 strbuf_release(&buf);
213
214 if (sha1)
215 git_SHA1_Final(sha1, &ctx);
216 if (hunk != RR_CONTEXT)
217 return -1;
218 return hunk_no;
219 }
220
221 static int handle_file(const char *path, unsigned char *sha1, const char *output)
222 {
223 int hunk_no = 0;
224 struct rerere_io_file io;
225 int marker_size = ll_merge_marker_size(path);
226
227 memset(&io, 0, sizeof(io));
228 io.io.getline = rerere_file_getline;
229 io.input = fopen(path, "r");
230 io.io.wrerror = 0;
231 if (!io.input)
232 return error("Could not open %s", path);
233
234 if (output) {
235 io.io.output = fopen(output, "w");
236 if (!io.io.output) {
237 fclose(io.input);
238 return error("Could not write %s", output);
239 }
240 }
241
242 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
243
244 fclose(io.input);
245 if (io.io.wrerror)
246 error("There were errors while writing %s (%s)",
247 path, strerror(io.io.wrerror));
248 if (io.io.output && fclose(io.io.output))
249 io.io.wrerror = error("Failed to flush %s: %s",
250 path, strerror(errno));
251
252 if (hunk_no < 0) {
253 if (output)
254 unlink_or_warn(output);
255 return error("Could not parse conflict hunks in %s", path);
256 }
257 if (io.io.wrerror)
258 return -1;
259 return hunk_no;
260 }
261
262 struct rerere_io_mem {
263 struct rerere_io io;
264 struct strbuf input;
265 };
266
267 static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
268 {
269 struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
270 char *ep;
271 size_t len;
272
273 strbuf_release(sb);
274 if (!io->input.len)
275 return -1;
276 ep = strchrnul(io->input.buf, '\n');
277 if (*ep == '\n')
278 ep++;
279 len = ep - io->input.buf;
280 strbuf_add(sb, io->input.buf, len);
281 strbuf_remove(&io->input, 0, len);
282 return 0;
283 }
284
285 static int handle_cache(const char *path, unsigned char *sha1, const char *output)
286 {
287 mmfile_t mmfile[3];
288 mmbuffer_t result = {NULL, 0};
289 struct cache_entry *ce;
290 int pos, len, i, hunk_no;
291 struct rerere_io_mem io;
292 int marker_size = ll_merge_marker_size(path);
293
294 /*
295 * Reproduce the conflicted merge in-core
296 */
297 len = strlen(path);
298 pos = cache_name_pos(path, len);
299 if (0 <= pos)
300 return -1;
301 pos = -pos - 1;
302
303 for (i = 0; i < 3; i++) {
304 enum object_type type;
305 unsigned long size;
306
307 mmfile[i].size = 0;
308 mmfile[i].ptr = NULL;
309 if (active_nr <= pos)
310 break;
311 ce = active_cache[pos++];
312 if (ce_namelen(ce) != len || memcmp(ce->name, path, len)
313 || ce_stage(ce) != i + 1)
314 break;
315 mmfile[i].ptr = read_sha1_file(ce->sha1, &type, &size);
316 mmfile[i].size = size;
317 }
318 for (i = 0; i < 3; i++) {
319 if (!mmfile[i].ptr && !mmfile[i].size)
320 mmfile[i].ptr = xstrdup("");
321 }
322 ll_merge(&result, path, &mmfile[0], NULL,
323 &mmfile[1], "ours",
324 &mmfile[2], "theirs", 0);
325 for (i = 0; i < 3; i++)
326 free(mmfile[i].ptr);
327
328 memset(&io, 0, sizeof(io));
329 io.io.getline = rerere_mem_getline;
330 if (output)
331 io.io.output = fopen(output, "w");
332 else
333 io.io.output = NULL;
334 strbuf_init(&io.input, 0);
335 strbuf_attach(&io.input, result.ptr, result.size, result.size);
336
337 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
338 strbuf_release(&io.input);
339 if (io.io.output)
340 fclose(io.io.output);
341 return hunk_no;
342 }
343
344 static int find_conflict(struct string_list *conflict)
345 {
346 int i;
347 if (read_cache() < 0)
348 return error("Could not read index");
349 for (i = 0; i+1 < active_nr; i++) {
350 struct cache_entry *e2 = active_cache[i];
351 struct cache_entry *e3 = active_cache[i+1];
352 if (ce_stage(e2) == 2 &&
353 ce_stage(e3) == 3 &&
354 ce_same_name(e2, e3) &&
355 S_ISREG(e2->ce_mode) &&
356 S_ISREG(e3->ce_mode)) {
357 string_list_insert(conflict, (const char *)e2->name);
358 i++; /* skip over both #2 and #3 */
359 }
360 }
361 return 0;
362 }
363
364 static int merge(const char *name, const char *path)
365 {
366 int ret;
367 mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
368 mmbuffer_t result = {NULL, 0};
369
370 if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
371 return 1;
372
373 if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
374 read_mmfile(&base, rerere_path(name, "preimage")) ||
375 read_mmfile(&other, rerere_path(name, "postimage"))) {
376 ret = 1;
377 goto out;
378 }
379 ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", 0);
380 if (!ret) {
381 FILE *f = fopen(path, "w");
382 if (!f)
383 return error("Could not open %s: %s", path,
384 strerror(errno));
385 if (fwrite(result.ptr, result.size, 1, f) != 1)
386 error("Could not write %s: %s", path, strerror(errno));
387 if (fclose(f))
388 return error("Writing %s failed: %s", path,
389 strerror(errno));
390 }
391
392 out:
393 free(cur.ptr);
394 free(base.ptr);
395 free(other.ptr);
396 free(result.ptr);
397
398 return ret;
399 }
400
401 static struct lock_file index_lock;
402
403 static int update_paths(struct string_list *update)
404 {
405 int i;
406 int fd = hold_locked_index(&index_lock, 0);
407 int status = 0;
408
409 if (fd < 0)
410 return -1;
411
412 for (i = 0; i < update->nr; i++) {
413 struct string_list_item *item = &update->items[i];
414 if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
415 status = -1;
416 }
417
418 if (!status && active_cache_changed) {
419 if (write_cache(fd, active_cache, active_nr) ||
420 commit_locked_index(&index_lock))
421 die("Unable to write new index file");
422 } else if (fd >= 0)
423 rollback_lock_file(&index_lock);
424 return status;
425 }
426
427 static int do_plain_rerere(struct string_list *rr, int fd)
428 {
429 struct string_list conflict = { NULL, 0, 0, 1 };
430 struct string_list update = { NULL, 0, 0, 1 };
431 int i;
432
433 find_conflict(&conflict);
434
435 /*
436 * MERGE_RR records paths with conflicts immediately after merge
437 * failed. Some of the conflicted paths might have been hand resolved
438 * in the working tree since then, but the initial run would catch all
439 * and register their preimages.
440 */
441
442 for (i = 0; i < conflict.nr; i++) {
443 const char *path = conflict.items[i].string;
444 if (!string_list_has_string(rr, path)) {
445 unsigned char sha1[20];
446 char *hex;
447 int ret;
448 ret = handle_file(path, sha1, NULL);
449 if (ret < 1)
450 continue;
451 hex = xstrdup(sha1_to_hex(sha1));
452 string_list_insert(rr, path)->util = hex;
453 if (mkdir(git_path("rr-cache/%s", hex), 0755))
454 continue;
455 handle_file(path, NULL, rerere_path(hex, "preimage"));
456 fprintf(stderr, "Recorded preimage for '%s'\n", path);
457 }
458 }
459
460 /*
461 * Now some of the paths that had conflicts earlier might have been
462 * hand resolved. Others may be similar to a conflict already that
463 * was resolved before.
464 */
465
466 for (i = 0; i < rr->nr; i++) {
467 int ret;
468 const char *path = rr->items[i].string;
469 const char *name = (const char *)rr->items[i].util;
470
471 if (has_rerere_resolution(name)) {
472 if (!merge(name, path)) {
473 if (rerere_autoupdate)
474 string_list_insert(&update, path);
475 fprintf(stderr,
476 "%s '%s' using previous resolution.\n",
477 rerere_autoupdate
478 ? "Staged" : "Resolved",
479 path);
480 goto mark_resolved;
481 }
482 }
483
484 /* Let's see if we have resolved it. */
485 ret = handle_file(path, NULL, NULL);
486 if (ret)
487 continue;
488
489 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
490 copy_file(rerere_path(name, "postimage"), path, 0666);
491 mark_resolved:
492 rr->items[i].util = NULL;
493 }
494
495 if (update.nr)
496 update_paths(&update);
497
498 return write_rr(rr, fd);
499 }
500
501 static int git_rerere_config(const char *var, const char *value, void *cb)
502 {
503 if (!strcmp(var, "rerere.enabled"))
504 rerere_enabled = git_config_bool(var, value);
505 else if (!strcmp(var, "rerere.autoupdate"))
506 rerere_autoupdate = git_config_bool(var, value);
507 else
508 return git_default_config(var, value, cb);
509 return 0;
510 }
511
512 static int is_rerere_enabled(void)
513 {
514 const char *rr_cache;
515 int rr_cache_exists;
516
517 if (!rerere_enabled)
518 return 0;
519
520 rr_cache = git_path("rr-cache");
521 rr_cache_exists = is_directory(rr_cache);
522 if (rerere_enabled < 0)
523 return rr_cache_exists;
524
525 if (!rr_cache_exists &&
526 (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
527 die("Could not create directory %s", rr_cache);
528 return 1;
529 }
530
531 int setup_rerere(struct string_list *merge_rr, int flags)
532 {
533 int fd;
534
535 git_config(git_rerere_config, NULL);
536 if (!is_rerere_enabled())
537 return -1;
538
539 if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
540 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
541 merge_rr_path = git_pathdup("MERGE_RR");
542 fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
543 LOCK_DIE_ON_ERROR);
544 read_rr(merge_rr);
545 return fd;
546 }
547
548 int rerere(int flags)
549 {
550 struct string_list merge_rr = { NULL, 0, 0, 1 };
551 int fd;
552
553 fd = setup_rerere(&merge_rr, flags);
554 if (fd < 0)
555 return 0;
556 return do_plain_rerere(&merge_rr, fd);
557 }
558
559 static int rerere_forget_one_path(const char *path, struct string_list *rr)
560 {
561 const char *filename;
562 char *hex;
563 unsigned char sha1[20];
564 int ret;
565
566 ret = handle_cache(path, sha1, NULL);
567 if (ret < 1)
568 return error("Could not parse conflict hunks in '%s'", path);
569 hex = xstrdup(sha1_to_hex(sha1));
570 filename = rerere_path(hex, "postimage");
571 if (unlink(filename))
572 return (errno == ENOENT
573 ? error("no remembered resolution for %s", path)
574 : error("cannot unlink %s: %s", filename, strerror(errno)));
575
576 handle_cache(path, sha1, rerere_path(hex, "preimage"));
577 fprintf(stderr, "Updated preimage for '%s'\n", path);
578
579
580 string_list_insert(rr, path)->util = hex;
581 fprintf(stderr, "Forgot resolution for %s\n", path);
582 return 0;
583 }
584
585 int rerere_forget(const char **pathspec)
586 {
587 int i, fd;
588 struct string_list conflict = { NULL, 0, 0, 1 };
589 struct string_list merge_rr = { NULL, 0, 0, 1 };
590
591 if (read_cache() < 0)
592 return error("Could not read index");
593
594 fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
595
596 unmerge_cache(pathspec);
597 find_conflict(&conflict);
598 for (i = 0; i < conflict.nr; i++) {
599 struct string_list_item *it = &conflict.items[i];
600 if (!match_pathspec(pathspec, it->string, strlen(it->string),
601 0, NULL))
602 continue;
603 rerere_forget_one_path(it->string, &merge_rr);
604 }
605 return write_rr(&merge_rr, fd);
606 }