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"
10 /* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
11 static int rerere_enabled = -1;
13 /* automatically update cleanly resolved paths to the index */
14 static int rerere_autoupdate;
16 static char *merge_rr_path;
18 const char *rerere_path(const char *hex, const char *file)
19 {
20 return git_path("rr-cache/%s/%s", hex, file);
21 }
23 int has_rerere_resolution(const char *hex)
24 {
25 struct stat st;
26 return !stat(rerere_path(hex, "postimage"), &st);
27 }
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 }
54 static struct lock_file write_lock;
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 }
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 }
84 static inline void ferr_puts(const char *s, FILE *fp, int *err)
85 {
86 ferr_write(s, strlen(s), fp, err);
87 }
89 struct rerere_io {
90 int (*getline)(struct strbuf *, struct rerere_io *);
91 FILE *output;
92 int wrerror;
93 /* some more stuff */
94 };
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 }
102 static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
103 {
104 char buf[64];
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 }
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 }
130 struct rerere_io_file {
131 struct rerere_io io;
132 FILE *input;
133 };
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 }
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 }
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;
161 if (sha1)
162 git_SHA1_Init(&ctx);
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);
214 if (sha1)
215 git_SHA1_Final(sha1, &ctx);
216 if (hunk != RR_CONTEXT)
217 return -1;
218 return hunk_no;
219 }
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);
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);
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 }
242 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
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));
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 }
262 struct rerere_io_mem {
263 struct rerere_io io;
264 struct strbuf input;
265 };
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;
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 }
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);
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;
303 for (i = 0; i < 3; i++) {
304 enum object_type type;
305 unsigned long size;
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 /*
323 * NEEDSWORK: handle conflicts from merges with
324 * merge.renormalize set, too
325 */
326 ll_merge(&result, path, &mmfile[0], NULL,
327 &mmfile[1], "ours",
328 &mmfile[2], "theirs", NULL);
329 for (i = 0; i < 3; i++)
330 free(mmfile[i].ptr);
332 memset(&io, 0, sizeof(io));
333 io.io.getline = rerere_mem_getline;
334 if (output)
335 io.io.output = fopen(output, "w");
336 else
337 io.io.output = NULL;
338 strbuf_init(&io.input, 0);
339 strbuf_attach(&io.input, result.ptr, result.size, result.size);
341 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
342 strbuf_release(&io.input);
343 if (io.io.output)
344 fclose(io.io.output);
345 return hunk_no;
346 }
348 static int find_conflict(struct string_list *conflict)
349 {
350 int i;
351 if (read_cache() < 0)
352 return error("Could not read index");
354 /*
355 * Collect paths with conflict, mark them with NULL (punted) or
356 * !NULL (eligible) in their ->util field.
357 */
358 for (i = 0; i < active_nr; i++) {
359 struct cache_entry *e = active_cache[i];
360 struct string_list_item *it;
362 if (!ce_stage(e))
363 continue;
364 it = string_list_insert(conflict, (const char *)e->name);
365 it->util = NULL;
366 if (ce_stage(e) == 1) {
367 if (active_nr <= ++i)
368 break;
369 }
371 /* Only handle regular files with both stages #2 and #3 */
372 if (i + 1 < active_nr) {
373 struct cache_entry *e2 = active_cache[i];
374 struct cache_entry *e3 = active_cache[i + 1];
375 if (ce_stage(e2) == 2 &&
376 ce_stage(e3) == 3 &&
377 ce_same_name(e, e3) &&
378 S_ISREG(e2->ce_mode) &&
379 S_ISREG(e3->ce_mode))
380 it->util = (void *) 1;
381 }
383 /* Skip the entries with the same name */
384 while (i < active_nr && ce_same_name(e, active_cache[i]))
385 i++;
386 i--; /* compensate for the outer loop */
387 }
388 return 0;
389 }
391 static void add_punted(struct string_list *merge_rr)
392 {
393 int i;
394 struct string_list conflict = STRING_LIST_INIT_DUP;
396 find_conflict(&conflict);
397 for (i = 0; i < conflict.nr; i++) {
398 if (conflict.items[i].util)
399 continue;
400 string_list_insert(merge_rr, conflict.items[i].string);
401 }
402 }
404 static int merge(const char *name, const char *path)
405 {
406 int ret;
407 mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
408 mmbuffer_t result = {NULL, 0};
410 if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
411 return 1;
413 if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
414 read_mmfile(&base, rerere_path(name, "preimage")) ||
415 read_mmfile(&other, rerere_path(name, "postimage"))) {
416 ret = 1;
417 goto out;
418 }
419 ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", 0);
420 if (!ret) {
421 FILE *f;
423 if (utime(rerere_path(name, "postimage"), NULL) < 0)
424 warning("failed utime() on %s: %s",
425 rerere_path(name, "postimage"),
426 strerror(errno));
427 f = fopen(path, "w");
428 if (!f)
429 return error("Could not open %s: %s", path,
430 strerror(errno));
431 if (fwrite(result.ptr, result.size, 1, f) != 1)
432 error("Could not write %s: %s", path, strerror(errno));
433 if (fclose(f))
434 return error("Writing %s failed: %s", path,
435 strerror(errno));
436 }
438 out:
439 free(cur.ptr);
440 free(base.ptr);
441 free(other.ptr);
442 free(result.ptr);
444 return ret;
445 }
447 static struct lock_file index_lock;
449 static int update_paths(struct string_list *update)
450 {
451 int i;
452 int fd = hold_locked_index(&index_lock, 0);
453 int status = 0;
455 if (fd < 0)
456 return -1;
458 for (i = 0; i < update->nr; i++) {
459 struct string_list_item *item = &update->items[i];
460 if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
461 status = -1;
462 }
464 if (!status && active_cache_changed) {
465 if (write_cache(fd, active_cache, active_nr) ||
466 commit_locked_index(&index_lock))
467 die("Unable to write new index file");
468 } else if (fd >= 0)
469 rollback_lock_file(&index_lock);
470 return status;
471 }
473 static int do_plain_rerere(struct string_list *rr, int fd)
474 {
475 struct string_list conflict = STRING_LIST_INIT_DUP;
476 struct string_list update = STRING_LIST_INIT_DUP;
477 int i;
479 find_conflict(&conflict);
481 /*
482 * MERGE_RR records paths with conflicts immediately after merge
483 * failed. Some of the conflicted paths might have been hand resolved
484 * in the working tree since then, but the initial run would catch all
485 * and register their preimages.
486 */
488 for (i = 0; i < conflict.nr; i++) {
489 const char *path = conflict.items[i].string;
490 if (!conflict.items[i].util)
491 continue; /* punted */
492 if (!string_list_has_string(rr, path)) {
493 unsigned char sha1[20];
494 char *hex;
495 int ret;
496 ret = handle_file(path, sha1, NULL);
497 if (ret < 1)
498 continue;
499 hex = xstrdup(sha1_to_hex(sha1));
500 string_list_insert(rr, path)->util = hex;
501 if (mkdir(git_path("rr-cache/%s", hex), 0755))
502 continue;
503 handle_file(path, NULL, rerere_path(hex, "preimage"));
504 fprintf(stderr, "Recorded preimage for '%s'\n", path);
505 }
506 }
508 /*
509 * Now some of the paths that had conflicts earlier might have been
510 * hand resolved. Others may be similar to a conflict already that
511 * was resolved before.
512 */
514 for (i = 0; i < rr->nr; i++) {
515 int ret;
516 const char *path = rr->items[i].string;
517 const char *name = (const char *)rr->items[i].util;
519 if (!name)
520 continue;
521 if (has_rerere_resolution(name)) {
522 if (!merge(name, path)) {
523 if (rerere_autoupdate)
524 string_list_insert(&update, path);
525 fprintf(stderr,
526 "%s '%s' using previous resolution.\n",
527 rerere_autoupdate
528 ? "Staged" : "Resolved",
529 path);
530 goto mark_resolved;
531 }
532 }
534 /* Let's see if we have resolved it. */
535 ret = handle_file(path, NULL, NULL);
536 if (ret)
537 continue;
539 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
540 copy_file(rerere_path(name, "postimage"), path, 0666);
541 mark_resolved:
542 rr->items[i].util = NULL;
543 }
545 if (update.nr)
546 update_paths(&update);
548 return write_rr(rr, fd);
549 }
551 static int git_rerere_config(const char *var, const char *value, void *cb)
552 {
553 if (!strcmp(var, "rerere.enabled"))
554 rerere_enabled = git_config_bool(var, value);
555 else if (!strcmp(var, "rerere.autoupdate"))
556 rerere_autoupdate = git_config_bool(var, value);
557 else
558 return git_default_config(var, value, cb);
559 return 0;
560 }
562 static int is_rerere_enabled(void)
563 {
564 const char *rr_cache;
565 int rr_cache_exists;
567 if (!rerere_enabled)
568 return 0;
570 rr_cache = git_path("rr-cache");
571 rr_cache_exists = is_directory(rr_cache);
572 if (rerere_enabled < 0)
573 return rr_cache_exists;
575 if (!rr_cache_exists &&
576 (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
577 die("Could not create directory %s", rr_cache);
578 return 1;
579 }
581 int setup_rerere(struct string_list *merge_rr, int flags)
582 {
583 int fd;
585 git_config(git_rerere_config, NULL);
586 if (!is_rerere_enabled())
587 return -1;
589 if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
590 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
591 merge_rr_path = git_pathdup("MERGE_RR");
592 fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
593 LOCK_DIE_ON_ERROR);
594 read_rr(merge_rr);
595 add_punted(merge_rr);
596 return fd;
597 }
599 int rerere(int flags)
600 {
601 struct string_list merge_rr = STRING_LIST_INIT_DUP;
602 int fd;
604 fd = setup_rerere(&merge_rr, flags);
605 if (fd < 0)
606 return 0;
607 return do_plain_rerere(&merge_rr, fd);
608 }
610 static int rerere_forget_one_path(const char *path, struct string_list *rr)
611 {
612 const char *filename;
613 char *hex;
614 unsigned char sha1[20];
615 int ret;
617 ret = handle_cache(path, sha1, NULL);
618 if (ret < 1)
619 return error("Could not parse conflict hunks in '%s'", path);
620 hex = xstrdup(sha1_to_hex(sha1));
621 filename = rerere_path(hex, "postimage");
622 if (unlink(filename))
623 return (errno == ENOENT
624 ? error("no remembered resolution for %s", path)
625 : error("cannot unlink %s: %s", filename, strerror(errno)));
627 handle_cache(path, sha1, rerere_path(hex, "preimage"));
628 fprintf(stderr, "Updated preimage for '%s'\n", path);
631 string_list_insert(rr, path)->util = hex;
632 fprintf(stderr, "Forgot resolution for %s\n", path);
633 return 0;
634 }
636 int rerere_forget(const char **pathspec)
637 {
638 int i, fd;
639 struct string_list conflict = STRING_LIST_INIT_DUP;
640 struct string_list merge_rr = STRING_LIST_INIT_DUP;
642 if (read_cache() < 0)
643 return error("Could not read index");
645 fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
647 unmerge_cache(pathspec);
648 find_conflict(&conflict);
649 for (i = 0; i < conflict.nr; i++) {
650 struct string_list_item *it = &conflict.items[i];
651 if (!conflict.items[i].util)
652 continue; /* punted */
653 if (!match_pathspec(pathspec, it->string, strlen(it->string),
654 0, NULL))
655 continue;
656 rerere_forget_one_path(it->string, &merge_rr);
657 }
658 return write_rr(&merge_rr, fd);
659 }