Merge branch 'cb/maint-orphan-merge-noclobber'
[git/kirr.git] / rerere.c
blobd2608434750c336c3f3881efda8373b7c67d4b11
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)
20 return git_path("rr-cache/%s/%s", hex, file);
23 int has_rerere_resolution(const char *hex)
25 struct stat st;
26 return !stat(rerere_path(hex, "postimage"), &st);
29 static void read_rr(struct string_list *rr)
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;
51 fclose(in);
54 static struct lock_file write_lock;
56 static int write_rr(struct string_list *rr, int out_fd)
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");
71 if (commit_lock_file(&write_lock) != 0)
72 die("unable to write rerere record");
73 return 0;
76 static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
78 if (!count || *err)
79 return;
80 if (fwrite(p, count, 1, fp) != 1)
81 *err = errno;
84 static inline void ferr_puts(const char *s, FILE *fp, int *err)
86 ferr_write(s, strlen(s), fp, err);
89 struct rerere_io {
90 int (*getline)(struct strbuf *, struct rerere_io *);
91 FILE *output;
92 int wrerror;
93 /* some more stuff */
96 static void rerere_io_putstr(const char *str, struct rerere_io *io)
98 if (io->output)
99 ferr_puts(str, io->output, &io->wrerror);
102 static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
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;
120 rerere_io_putstr(buf, io);
124 static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
126 if (io->output)
127 ferr_write(mem, sz, io->output, &io->wrerror);
130 struct rerere_io_file {
131 struct rerere_io io;
132 FILE *input;
135 static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
137 struct rerere_io_file *io = (struct rerere_io_file *)io_;
138 return strbuf_getwholeline(sb, io->input, '\n');
141 static int is_cmarker(char *buf, int marker_char, int marker_size, int want_sp)
143 while (marker_size--)
144 if (*buf++ != marker_char)
145 return 0;
146 if (want_sp && *buf != ' ')
147 return 0;
148 return isspace(*buf);
151 static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
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);
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;
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;
221 static int handle_file(const char *path, unsigned char *sha1, const char *output)
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);
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);
257 if (io.io.wrerror)
258 return -1;
259 return hunk_no;
262 struct rerere_io_mem {
263 struct rerere_io io;
264 struct strbuf input;
267 static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
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;
285 static int handle_cache(const char *path, unsigned char *sha1, const char *output)
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);
295 * Reproduce the conflicted merge in-core
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;
318 for (i = 0; i < 3; i++) {
319 if (!mmfile[i].ptr && !mmfile[i].size)
320 mmfile[i].ptr = xstrdup("");
323 * NEEDSWORK: handle conflicts from merges with
324 * merge.renormalize set, too
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;
348 static int find_conflict(struct string_list *conflict)
350 int i;
351 if (read_cache() < 0)
352 return error("Could not read index");
353 for (i = 0; i+1 < active_nr; i++) {
354 struct cache_entry *e2 = active_cache[i];
355 struct cache_entry *e3 = active_cache[i+1];
356 if (ce_stage(e2) == 2 &&
357 ce_stage(e3) == 3 &&
358 ce_same_name(e2, e3) &&
359 S_ISREG(e2->ce_mode) &&
360 S_ISREG(e3->ce_mode)) {
361 string_list_insert(conflict, (const char *)e2->name);
362 i++; /* skip over both #2 and #3 */
365 return 0;
368 static int merge(const char *name, const char *path)
370 int ret;
371 mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
372 mmbuffer_t result = {NULL, 0};
374 if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
375 return 1;
377 if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
378 read_mmfile(&base, rerere_path(name, "preimage")) ||
379 read_mmfile(&other, rerere_path(name, "postimage"))) {
380 ret = 1;
381 goto out;
383 ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", 0);
384 if (!ret) {
385 FILE *f;
387 if (utime(rerere_path(name, "postimage"), NULL) < 0)
388 warning("failed utime() on %s: %s",
389 rerere_path(name, "postimage"),
390 strerror(errno));
391 f = fopen(path, "w");
392 if (!f)
393 return error("Could not open %s: %s", path,
394 strerror(errno));
395 if (fwrite(result.ptr, result.size, 1, f) != 1)
396 error("Could not write %s: %s", path, strerror(errno));
397 if (fclose(f))
398 return error("Writing %s failed: %s", path,
399 strerror(errno));
402 out:
403 free(cur.ptr);
404 free(base.ptr);
405 free(other.ptr);
406 free(result.ptr);
408 return ret;
411 static struct lock_file index_lock;
413 static int update_paths(struct string_list *update)
415 int i;
416 int fd = hold_locked_index(&index_lock, 0);
417 int status = 0;
419 if (fd < 0)
420 return -1;
422 for (i = 0; i < update->nr; i++) {
423 struct string_list_item *item = &update->items[i];
424 if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
425 status = -1;
428 if (!status && active_cache_changed) {
429 if (write_cache(fd, active_cache, active_nr) ||
430 commit_locked_index(&index_lock))
431 die("Unable to write new index file");
432 } else if (fd >= 0)
433 rollback_lock_file(&index_lock);
434 return status;
437 static int do_plain_rerere(struct string_list *rr, int fd)
439 struct string_list conflict = STRING_LIST_INIT_DUP;
440 struct string_list update = STRING_LIST_INIT_DUP;
441 int i;
443 find_conflict(&conflict);
446 * MERGE_RR records paths with conflicts immediately after merge
447 * failed. Some of the conflicted paths might have been hand resolved
448 * in the working tree since then, but the initial run would catch all
449 * and register their preimages.
452 for (i = 0; i < conflict.nr; i++) {
453 const char *path = conflict.items[i].string;
454 if (!string_list_has_string(rr, path)) {
455 unsigned char sha1[20];
456 char *hex;
457 int ret;
458 ret = handle_file(path, sha1, NULL);
459 if (ret < 1)
460 continue;
461 hex = xstrdup(sha1_to_hex(sha1));
462 string_list_insert(rr, path)->util = hex;
463 if (mkdir(git_path("rr-cache/%s", hex), 0755))
464 continue;
465 handle_file(path, NULL, rerere_path(hex, "preimage"));
466 fprintf(stderr, "Recorded preimage for '%s'\n", path);
471 * Now some of the paths that had conflicts earlier might have been
472 * hand resolved. Others may be similar to a conflict already that
473 * was resolved before.
476 for (i = 0; i < rr->nr; i++) {
477 int ret;
478 const char *path = rr->items[i].string;
479 const char *name = (const char *)rr->items[i].util;
481 if (has_rerere_resolution(name)) {
482 if (!merge(name, path)) {
483 if (rerere_autoupdate)
484 string_list_insert(&update, path);
485 fprintf(stderr,
486 "%s '%s' using previous resolution.\n",
487 rerere_autoupdate
488 ? "Staged" : "Resolved",
489 path);
490 goto mark_resolved;
494 /* Let's see if we have resolved it. */
495 ret = handle_file(path, NULL, NULL);
496 if (ret)
497 continue;
499 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
500 copy_file(rerere_path(name, "postimage"), path, 0666);
501 mark_resolved:
502 rr->items[i].util = NULL;
505 if (update.nr)
506 update_paths(&update);
508 return write_rr(rr, fd);
511 static int git_rerere_config(const char *var, const char *value, void *cb)
513 if (!strcmp(var, "rerere.enabled"))
514 rerere_enabled = git_config_bool(var, value);
515 else if (!strcmp(var, "rerere.autoupdate"))
516 rerere_autoupdate = git_config_bool(var, value);
517 else
518 return git_default_config(var, value, cb);
519 return 0;
522 static int is_rerere_enabled(void)
524 const char *rr_cache;
525 int rr_cache_exists;
527 if (!rerere_enabled)
528 return 0;
530 rr_cache = git_path("rr-cache");
531 rr_cache_exists = is_directory(rr_cache);
532 if (rerere_enabled < 0)
533 return rr_cache_exists;
535 if (!rr_cache_exists &&
536 (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
537 die("Could not create directory %s", rr_cache);
538 return 1;
541 int setup_rerere(struct string_list *merge_rr, int flags)
543 int fd;
545 git_config(git_rerere_config, NULL);
546 if (!is_rerere_enabled())
547 return -1;
549 if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
550 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
551 merge_rr_path = git_pathdup("MERGE_RR");
552 fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
553 LOCK_DIE_ON_ERROR);
554 read_rr(merge_rr);
555 return fd;
558 int rerere(int flags)
560 struct string_list merge_rr = STRING_LIST_INIT_DUP;
561 int fd;
563 fd = setup_rerere(&merge_rr, flags);
564 if (fd < 0)
565 return 0;
566 return do_plain_rerere(&merge_rr, fd);
569 static int rerere_forget_one_path(const char *path, struct string_list *rr)
571 const char *filename;
572 char *hex;
573 unsigned char sha1[20];
574 int ret;
576 ret = handle_cache(path, sha1, NULL);
577 if (ret < 1)
578 return error("Could not parse conflict hunks in '%s'", path);
579 hex = xstrdup(sha1_to_hex(sha1));
580 filename = rerere_path(hex, "postimage");
581 if (unlink(filename))
582 return (errno == ENOENT
583 ? error("no remembered resolution for %s", path)
584 : error("cannot unlink %s: %s", filename, strerror(errno)));
586 handle_cache(path, sha1, rerere_path(hex, "preimage"));
587 fprintf(stderr, "Updated preimage for '%s'\n", path);
590 string_list_insert(rr, path)->util = hex;
591 fprintf(stderr, "Forgot resolution for %s\n", path);
592 return 0;
595 int rerere_forget(const char **pathspec)
597 int i, fd;
598 struct string_list conflict = STRING_LIST_INIT_DUP;
599 struct string_list merge_rr = STRING_LIST_INIT_DUP;
601 if (read_cache() < 0)
602 return error("Could not read index");
604 fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
606 unmerge_cache(pathspec);
607 find_conflict(&conflict);
608 for (i = 0; i < conflict.nr; i++) {
609 struct string_list_item *it = &conflict.items[i];
610 if (!match_pathspec(pathspec, it->string, strlen(it->string),
611 0, NULL))
612 continue;
613 rerere_forget_one_path(it->string, &merge_rr);
615 return write_rr(&merge_rr, fd);