1#include "cache.h" 2#include "lockfile.h" 3#include "string-list.h" 4#include "rerere.h" 5#include "xdiff-interface.h" 6#include "dir.h" 7#include "resolve-undo.h" 8#include "ll-merge.h" 9#include "attr.h" 10#include "pathspec.h" 11 12#define RESOLVED 0 13#define PUNTED 1 14#define THREE_STAGED 2 15void *RERERE_RESOLVED = &RERERE_RESOLVED; 16 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 25static void free_rerere_id(struct string_list_item *item) 26{ 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); 41} 42 43static int has_rerere_resolution(const struct rerere_id *id) 44{ 45 struct stat st; 46 47 return !stat(rerere_path(id, "postimage"), &st); 48} 49 50static struct rerere_id *new_rerere_id_hex(char *hex) 51{ 52 struct rerere_id *id = xmalloc(sizeof(*id)); 53 strcpy(id->hex, hex); 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 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 */ 69static void read_rr(struct string_list *rr) 70{ 71 struct strbuf buf = STRBUF_INIT; 72 FILE *in = fopen(merge_rr_path, "r"); 73 74 if (!in) 75 return; 76 while (!strbuf_getwholeline(&buf, in, '\0')) { 77 char *path; 78 unsigned char sha1[20]; 79 struct rerere_id *id; 80 81 /* There has to be the hash, tab, path and then NUL */ 82 if (buf.len < 42 || get_sha1_hex(buf.buf, sha1)) 83 die("corrupt MERGE_RR"); 84 85 if (buf.buf[40] != '\t') 86 die("corrupt MERGE_RR"); 87 buf.buf[40] = '\0'; 88 path = buf.buf + 41; 89 id = new_rerere_id_hex(buf.buf); 90 string_list_insert(rr, path)->util = id; 91 } 92 strbuf_release(&buf); 93 fclose(in); 94} 95 96static struct lock_file write_lock; 97 98static int write_rr(struct string_list *rr, int out_fd) 99{ 100 int i; 101 for (i = 0; i < rr->nr; i++) { 102 struct strbuf buf = STRBUF_INIT; 103 struct rerere_id *id; 104 105 assert(rr->items[i].util != RERERE_RESOLVED); 106 107 id = rr->items[i].util; 108 if (!id) 109 continue; 110 strbuf_addf(&buf, "%s\t%s%c", 111 rerere_id_hex(id), 112 rr->items[i].string, 0); 113 if (write_in_full(out_fd, buf.buf, buf.len) != buf.len) 114 die("unable to write rerere record"); 115 116 strbuf_release(&buf); 117 } 118 if (commit_lock_file(&write_lock) != 0) 119 die("unable to write rerere record"); 120 return 0; 121} 122 123/* 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 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 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} 156 157/* 158 * Write a conflict marker to io->output (if defined). 159 */ 160static void rerere_io_putconflict(int ch, int size, struct rerere_io *io) 161{ 162 char buf[64]; 163 164 while (size) { 165 if (size <= sizeof(buf) - 2) { 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; 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 */ 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 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} 194 195/* 196 * Subclass of rerere_io that reads from an on-disk file 197 */ 198struct rerere_io_file { 199 struct rerere_io io; 200 FILE *input; 201}; 202 203/* 204 * ... and its getline() method implementation 205 */ 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} 211 212/* 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) 218{ 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 == '>'); 230 231 while (marker_size--) 232 if (*buf++ != marker_char) 233 return 0; 234 if (want_sp && *buf != ' ') 235 return 0; 236 return isspace(*buf); 237} 238 239/* 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 */ 254static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size) 255{ 256 git_SHA_CTX ctx; 257 int hunk_no = 0; 258 enum { 259 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL 260 } hunk = RR_CONTEXT; 261 struct strbuf one = STRBUF_INIT, two = STRBUF_INIT; 262 struct strbuf buf = STRBUF_INIT; 263 264 if (sha1) 265 git_SHA1_Init(&ctx); 266 267 while (!io->getline(&buf, io)) { 268 if (is_cmarker(buf.buf, '<', marker_size)) { 269 if (hunk != RR_CONTEXT) 270 goto bad; 271 hunk = RR_SIDE_1; 272 } else if (is_cmarker(buf.buf, '|', marker_size)) { 273 if (hunk != RR_SIDE_1) 274 goto bad; 275 hunk = RR_ORIGINAL; 276 } else if (is_cmarker(buf.buf, '=', marker_size)) { 277 if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL) 278 goto bad; 279 hunk = RR_SIDE_2; 280 } else if (is_cmarker(buf.buf, '>', marker_size)) { 281 if (hunk != RR_SIDE_2) 282 goto bad; 283 if (strbuf_cmp(&one, &two) > 0) 284 strbuf_swap(&one, &two); 285 hunk_no++; 286 hunk = RR_CONTEXT; 287 rerere_io_putconflict('<', marker_size, io); 288 rerere_io_putmem(one.buf, one.len, io); 289 rerere_io_putconflict('=', marker_size, io); 290 rerere_io_putmem(two.buf, two.len, io); 291 rerere_io_putconflict('>', marker_size, io); 292 if (sha1) { 293 git_SHA1_Update(&ctx, one.buf ? one.buf : "", 294 one.len + 1); 295 git_SHA1_Update(&ctx, two.buf ? two.buf : "", 296 two.len + 1); 297 } 298 strbuf_reset(&one); 299 strbuf_reset(&two); 300 } else if (hunk == RR_SIDE_1) 301 strbuf_addbuf(&one, &buf); 302 else if (hunk == RR_ORIGINAL) 303 ; /* discard */ 304 else if (hunk == RR_SIDE_2) 305 strbuf_addbuf(&two, &buf); 306 else 307 rerere_io_putstr(buf.buf, io); 308 continue; 309 bad: 310 hunk = 99; /* force error exit */ 311 break; 312 } 313 strbuf_release(&one); 314 strbuf_release(&two); 315 strbuf_release(&buf); 316 317 if (sha1) 318 git_SHA1_Final(sha1, &ctx); 319 if (hunk != RR_CONTEXT) 320 return -1; 321 return hunk_no; 322} 323 324/* 325 * Scan the path for conflicts, do the "handle_path()" thing above, and 326 * return the number of conflict hunks found. 327 */ 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; 332 int marker_size = ll_merge_marker_size(path); 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 } 348 349 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size); 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) { 360 if (output) 361 unlink_or_warn(output); 362 return error("Could not parse conflict hunks in %s", path); 363 } 364 if (io.io.wrerror) 365 return -1; 366 return hunk_no; 367} 368 369/* 370 * Subclass of rerere_io that reads from an in-core buffer that is a 371 * strbuf 372 */ 373struct rerere_io_mem { 374 struct rerere_io io; 375 struct strbuf input; 376}; 377 378/* 379 * ... and its getline() method implementation 380 */ 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; 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') 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{ 403 mmfile_t mmfile[3] = {{NULL}}; 404 mmbuffer_t result = {NULL, 0}; 405 const struct cache_entry *ce; 406 int pos, len, i, hunk_no; 407 struct rerere_io_mem io; 408 int marker_size = ll_merge_marker_size(path); 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) 416 return -1; 417 pos = -pos - 1; 418 419 while (pos < active_nr) { 420 enum object_type type; 421 unsigned long size; 422 423 ce = active_cache[pos++]; 424 if (ce_namelen(ce) != len || memcmp(ce->name, path, len)) 425 break; 426 i = ce_stage(ce) - 1; 427 if (!mmfile[i].ptr) { 428 mmfile[i].ptr = read_sha1_file(ce->sha1, &type, &size); 429 mmfile[i].size = size; 430 } 431 } 432 for (i = 0; i < 3; i++) 433 if (!mmfile[i].ptr && !mmfile[i].size) 434 mmfile[i].ptr = xstrdup(""); 435 436 /* 437 * NEEDSWORK: handle conflicts from merges with 438 * merge.renormalize set, too 439 */ 440 ll_merge(&result, path, &mmfile[0], NULL, 441 &mmfile[1], "ours", 442 &mmfile[2], "theirs", NULL); 443 for (i = 0; i < 3; i++) 444 free(mmfile[i].ptr); 445 446 memset(&io, 0, sizeof(io)); 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); 454 455 /* 456 * Grab the conflict ID and optionally write the original 457 * contents with conflict markers out. 458 */ 459 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size); 460 strbuf_release(&io.input); 461 if (io.io.output) 462 fclose(io.io.output); 463 return hunk_no; 464} 465 466/* 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 */ 474static int check_one_conflict(int i, int *type) 475{ 476 const struct cache_entry *e = active_cache[i]; 477 478 if (!ce_stage(e)) { 479 *type = RESOLVED; 480 return i + 1; 481 } 482 483 *type = PUNTED; 484 while (ce_stage(active_cache[i]) == 1) 485 i++; 486 487 /* Only handle regular files with both stages #2 and #3 */ 488 if (i + 1 < active_nr) { 489 const struct cache_entry *e2 = active_cache[i]; 490 const struct cache_entry *e3 = active_cache[i + 1]; 491 if (ce_stage(e2) == 2 && 492 ce_stage(e3) == 3 && 493 ce_same_name(e, e3) && 494 S_ISREG(e2->ce_mode) && 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} 504 505/* 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 */ 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; 524 const struct cache_entry *e = active_cache[i]; 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} 531 532/* 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 */ 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; 555 const struct cache_entry *e = active_cache[i]; 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) { 563 free_rerere_id(it); 564 it->util = RERERE_RESOLVED; 565 } 566 } 567 } 568 return 0; 569} 570 571/* 572 * Find the conflict identified by "id"; the change between its 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 */ 581static int merge(const struct rerere_id *id, const char *path) 582{ 583 int ret; 584 mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0}; 585 mmbuffer_t result = {NULL, 0}; 586 587 /* 588 * Normalize the conflicts in path and write it out to 589 * "thisimage" temporary file. 590 */ 591 if (handle_file(path, NULL, rerere_path(id, "thisimage")) < 0) 592 return 1; 593 594 if (read_mmfile(&cur, rerere_path(id, "thisimage")) || 595 read_mmfile(&base, rerere_path(id, "preimage")) || 596 read_mmfile(&other, rerere_path(id, "postimage"))) { 597 ret = 1; 598 goto out; 599 } 600 601 /* 602 * A three-way merge. Note that this honors user-customizable 603 * low-level merge driver settings. 604 */ 605 ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", NULL); 606 if (!ret) { 607 FILE *f; 608 609 /* 610 * A successful replay of recorded resolution. 611 * Mark that "postimage" was used to help gc. 612 */ 613 if (utime(rerere_path(id, "postimage"), NULL) < 0) 614 warning("failed utime() on %s: %s", 615 rerere_path(id, "postimage"), 616 strerror(errno)); 617 618 /* Update "path" with the resolution */ 619 f = fopen(path, "w"); 620 if (!f) 621 return error("Could not open %s: %s", path, 622 strerror(errno)); 623 if (fwrite(result.ptr, result.size, 1, f) != 1) 624 error("Could not write %s: %s", path, strerror(errno)); 625 if (fclose(f)) 626 return error("Writing %s failed: %s", path, 627 strerror(errno)); 628 } 629 630out: 631 free(cur.ptr); 632 free(base.ptr); 633 free(other.ptr); 634 free(result.ptr); 635 636 return ret; 637} 638 639static struct lock_file index_lock; 640 641static void update_paths(struct string_list *update) 642{ 643 int i; 644 645 hold_locked_index(&index_lock, 1); 646 647 for (i = 0; i < update->nr; i++) { 648 struct string_list_item *item = &update->items[i]; 649 if (add_file_to_cache(item->string, 0)) 650 exit(128); 651 fprintf(stderr, "Staged '%s' using previous resolution.\n", 652 item->string); 653 } 654 655 if (active_cache_changed) { 656 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK)) 657 die("Unable to write new index file"); 658 } else 659 rollback_lock_file(&index_lock); 660} 661 662/* 663 * The path indicated by rr_item may still have conflict for which we 664 * have a recorded resolution, in which case replay it and optionally 665 * update it. Or it may have been resolved by the user and we may 666 * only have the preimage for that conflict, in which case the result 667 * needs to be recorded as a resolution in a postimage file. 668 */ 669static void do_rerere_one_path(struct string_list_item *rr_item, 670 struct string_list *update) 671{ 672 const char *path = rr_item->string; 673 const struct rerere_id *id = rr_item->util; 674 675 /* Is there a recorded resolution we could attempt to apply? */ 676 if (has_rerere_resolution(id)) { 677 if (merge(id, path)) 678 return; /* failed to replay */ 679 680 if (rerere_autoupdate) 681 string_list_insert(update, path); 682 else 683 fprintf(stderr, 684 "Resolved '%s' using previous resolution.\n", 685 path); 686 } else if (!handle_file(path, NULL, NULL)) { 687 /* The user has resolved it. */ 688 copy_file(rerere_path(id, "postimage"), path, 0666); 689 fprintf(stderr, "Recorded resolution for '%s'.\n", path); 690 } else { 691 return; 692 } 693 free_rerere_id(rr_item); 694 rr_item->util = NULL; 695} 696 697static int do_plain_rerere(struct string_list *rr, int fd) 698{ 699 struct string_list conflict = STRING_LIST_INIT_DUP; 700 struct string_list update = STRING_LIST_INIT_DUP; 701 int i; 702 703 find_conflict(&conflict); 704 705 /* 706 * MERGE_RR records paths with conflicts immediately after 707 * merge failed. Some of the conflicted paths might have been 708 * hand resolved in the working tree since then, but the 709 * initial run would catch all and register their preimages. 710 */ 711 for (i = 0; i < conflict.nr; i++) { 712 struct rerere_id *id; 713 unsigned char sha1[20]; 714 const char *path = conflict.items[i].string; 715 int ret; 716 717 if (string_list_has_string(rr, path)) 718 continue; 719 720 /* 721 * Ask handle_file() to scan and assign a 722 * conflict ID. No need to write anything out 723 * yet. 724 */ 725 ret = handle_file(path, sha1, NULL); 726 if (ret < 1) 727 continue; 728 729 id = new_rerere_id(sha1); 730 string_list_insert(rr, path)->util = id; 731 732 /* 733 * If the directory does not exist, create 734 * it. mkdir_in_gitdir() will fail with 735 * EEXIST if there already is one. 736 * 737 * NEEDSWORK: make sure "gc" does not remove 738 * preimage without removing the directory. 739 */ 740 if (mkdir_in_gitdir(rerere_path(id, NULL))) 741 continue; 742 743 /* 744 * We are the first to encounter this 745 * conflict. Ask handle_file() to write the 746 * normalized contents to the "preimage" file. 747 */ 748 handle_file(path, NULL, rerere_path(id, "preimage")); 749 fprintf(stderr, "Recorded preimage for '%s'\n", path); 750 } 751 752 for (i = 0; i < rr->nr; i++) 753 do_rerere_one_path(&rr->items[i], &update); 754 755 if (update.nr) 756 update_paths(&update); 757 758 return write_rr(rr, fd); 759} 760 761static void git_rerere_config(void) 762{ 763 git_config_get_bool("rerere.enabled", &rerere_enabled); 764 git_config_get_bool("rerere.autoupdate", &rerere_autoupdate); 765 git_config(git_default_config, NULL); 766} 767 768static int is_rerere_enabled(void) 769{ 770 const char *rr_cache; 771 int rr_cache_exists; 772 773 if (!rerere_enabled) 774 return 0; 775 776 rr_cache = git_path("rr-cache"); 777 rr_cache_exists = is_directory(rr_cache); 778 if (rerere_enabled < 0) 779 return rr_cache_exists; 780 781 if (!rr_cache_exists && mkdir_in_gitdir(rr_cache)) 782 die("Could not create directory %s", rr_cache); 783 return 1; 784} 785 786int setup_rerere(struct string_list *merge_rr, int flags) 787{ 788 int fd; 789 790 git_rerere_config(); 791 if (!is_rerere_enabled()) 792 return -1; 793 794 if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE)) 795 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE); 796 merge_rr_path = git_pathdup("MERGE_RR"); 797 fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 798 LOCK_DIE_ON_ERROR); 799 read_rr(merge_rr); 800 return fd; 801} 802 803/* 804 * The main entry point that is called internally from codepaths that 805 * perform mergy operations, possibly leaving conflicted index entries 806 * and working tree files. 807 */ 808int rerere(int flags) 809{ 810 struct string_list merge_rr = STRING_LIST_INIT_DUP; 811 int fd; 812 813 fd = setup_rerere(&merge_rr, flags); 814 if (fd < 0) 815 return 0; 816 return do_plain_rerere(&merge_rr, fd); 817} 818 819static int rerere_forget_one_path(const char *path, struct string_list *rr) 820{ 821 const char *filename; 822 struct rerere_id *id; 823 unsigned char sha1[20]; 824 int ret; 825 struct string_list_item *item; 826 827 /* 828 * Recreate the original conflict from the stages in the 829 * index and compute the conflict ID 830 */ 831 ret = handle_cache(path, sha1, NULL); 832 if (ret < 1) 833 return error("Could not parse conflict hunks in '%s'", path); 834 835 /* Nuke the recorded resolution for the conflict */ 836 id = new_rerere_id(sha1); 837 filename = rerere_path(id, "postimage"); 838 if (unlink(filename)) 839 return (errno == ENOENT 840 ? error("no remembered resolution for %s", path) 841 : error("cannot unlink %s: %s", filename, strerror(errno))); 842 843 /* 844 * Update the preimage so that the user can resolve the 845 * conflict in the working tree, run us again to record 846 * the postimage. 847 */ 848 handle_cache(path, sha1, rerere_path(id, "preimage")); 849 fprintf(stderr, "Updated preimage for '%s'\n", path); 850 851 /* 852 * And remember that we can record resolution for this 853 * conflict when the user is done. 854 */ 855 item = string_list_insert(rr, path); 856 free_rerere_id(item); 857 item->util = id; 858 fprintf(stderr, "Forgot resolution for %s\n", path); 859 return 0; 860} 861 862int rerere_forget(struct pathspec *pathspec) 863{ 864 int i, fd; 865 struct string_list conflict = STRING_LIST_INIT_DUP; 866 struct string_list merge_rr = STRING_LIST_INIT_DUP; 867 868 if (read_cache() < 0) 869 return error("Could not read index"); 870 871 fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE); 872 873 /* 874 * The paths may have been resolved (incorrectly); 875 * recover the original conflicted state and then 876 * find the conflicted paths. 877 */ 878 unmerge_cache(pathspec); 879 find_conflict(&conflict); 880 for (i = 0; i < conflict.nr; i++) { 881 struct string_list_item *it = &conflict.items[i]; 882 if (!match_pathspec(pathspec, it->string, 883 strlen(it->string), 0, NULL, 0)) 884 continue; 885 rerere_forget_one_path(it->string, &merge_rr); 886 } 887 return write_rr(&merge_rr, fd); 888} 889 890/* 891 * Garbage collection support 892 */ 893 894/* 895 * Note that this is not reentrant but is used only one-at-a-time 896 * so it does not matter right now. 897 */ 898static struct rerere_id *dirname_to_id(const char *name) 899{ 900 static struct rerere_id id; 901 strcpy(id.hex, name); 902 return &id; 903} 904 905static time_t rerere_created_at(const char *dir_name) 906{ 907 struct stat st; 908 struct rerere_id *id = dirname_to_id(dir_name); 909 910 return stat(rerere_path(id, "preimage"), &st) ? (time_t) 0 : st.st_mtime; 911} 912 913static time_t rerere_last_used_at(const char *dir_name) 914{ 915 struct stat st; 916 struct rerere_id *id = dirname_to_id(dir_name); 917 918 return stat(rerere_path(id, "postimage"), &st) ? (time_t) 0 : st.st_mtime; 919} 920 921/* 922 * Remove the recorded resolution for a given conflict ID 923 */ 924static void unlink_rr_item(struct rerere_id *id) 925{ 926 unlink(rerere_path(id, "thisimage")); 927 unlink(rerere_path(id, "preimage")); 928 unlink(rerere_path(id, "postimage")); 929 /* 930 * NEEDSWORK: what if this rmdir() fails? Wouldn't we then 931 * assume that we already have preimage recorded in 932 * do_plain_rerere()? 933 */ 934 rmdir(rerere_path(id, NULL)); 935} 936 937void rerere_gc(struct string_list *rr) 938{ 939 struct string_list to_remove = STRING_LIST_INIT_DUP; 940 DIR *dir; 941 struct dirent *e; 942 int i, cutoff; 943 time_t now = time(NULL), then; 944 int cutoff_noresolve = 15; 945 int cutoff_resolve = 60; 946 947 git_config_get_int("gc.rerereresolved", &cutoff_resolve); 948 git_config_get_int("gc.rerereunresolved", &cutoff_noresolve); 949 git_config(git_default_config, NULL); 950 dir = opendir(git_path("rr-cache")); 951 if (!dir) 952 die_errno("unable to open rr-cache directory"); 953 /* Collect stale conflict IDs ... */ 954 while ((e = readdir(dir))) { 955 if (is_dot_or_dotdot(e->d_name)) 956 continue; 957 958 then = rerere_last_used_at(e->d_name); 959 if (then) { 960 cutoff = cutoff_resolve; 961 } else { 962 then = rerere_created_at(e->d_name); 963 if (!then) 964 continue; 965 cutoff = cutoff_noresolve; 966 } 967 if (then < now - cutoff * 86400) 968 string_list_append(&to_remove, e->d_name); 969 } 970 closedir(dir); 971 /* ... and then remove them one-by-one */ 972 for (i = 0; i < to_remove.nr; i++) 973 unlink_rr_item(dirname_to_id(to_remove.items[i].string)); 974 string_list_clear(&to_remove, 0); 975} 976 977/* 978 * During a conflict resolution, after "rerere" recorded the 979 * preimages, abandon them if the user did not resolve them or 980 * record their resolutions. And drop $GIT_DIR/MERGE_RR. 981 * 982 * NEEDSWORK: shouldn't we be calling this from "reset --hard"? 983 */ 984void rerere_clear(struct string_list *merge_rr) 985{ 986 int i; 987 988 for (i = 0; i < merge_rr->nr; i++) { 989 struct rerere_id *id = merge_rr->items[i].util; 990 if (!has_rerere_resolution(id)) 991 unlink_rr_item(id); 992 } 993 unlink_or_warn(git_path("MERGE_RR")); 994}