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#include "sha1-lookup.h" 12 13#define RESOLVED 0 14#define PUNTED 1 15#define THREE_STAGED 2 16void *RERERE_RESOLVED = &RERERE_RESOLVED; 17 18/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */ 19static int rerere_enabled = -1; 20 21/* automatically update cleanly resolved paths to the index */ 22static int rerere_autoupdate; 23 24static char *merge_rr_path; 25 26static int rerere_dir_nr; 27static int rerere_dir_alloc; 28 29#define RR_HAS_POSTIMAGE 1 30#define RR_HAS_PREIMAGE 2 31static struct rerere_dir { 32 unsigned char sha1[20]; 33 unsigned char status; 34} **rerere_dir; 35 36static void free_rerere_dirs(void) 37{ 38 int i; 39 for (i = 0; i < rerere_dir_nr; i++) 40 free(rerere_dir[i]); 41 free(rerere_dir); 42 rerere_dir_nr = rerere_dir_alloc = 0; 43 rerere_dir = NULL; 44} 45 46static void free_rerere_id(struct string_list_item *item) 47{ 48 free(item->util); 49} 50 51static const char *rerere_id_hex(const struct rerere_id *id) 52{ 53 return sha1_to_hex(id->collection->sha1); 54} 55 56const char *rerere_path(const struct rerere_id *id, const char *file) 57{ 58 if (!file) 59 return git_path("rr-cache/%s", rerere_id_hex(id)); 60 61 return git_path("rr-cache/%s/%s", rerere_id_hex(id), file); 62} 63 64static int is_rr_file(const char *name, const char *filename) 65{ 66 return !strcmp(name, filename); 67} 68 69static void scan_rerere_dir(struct rerere_dir *rr_dir) 70{ 71 struct dirent *de; 72 DIR *dir = opendir(git_path("rr-cache/%s", sha1_to_hex(rr_dir->sha1))); 73 74 if (!dir) 75 return; 76 while ((de = readdir(dir)) != NULL) { 77 if (is_rr_file(de->d_name, "postimage")) 78 rr_dir->status |= RR_HAS_POSTIMAGE; 79 else if (is_rr_file(de->d_name, "preimage")) 80 rr_dir->status |= RR_HAS_PREIMAGE; 81 } 82 closedir(dir); 83} 84 85static const unsigned char *rerere_dir_sha1(size_t i, void *table) 86{ 87 struct rerere_dir **rr_dir = table; 88 return rr_dir[i]->sha1; 89} 90 91static struct rerere_dir *find_rerere_dir(const char *hex) 92{ 93 unsigned char sha1[20]; 94 struct rerere_dir *rr_dir; 95 int pos; 96 97 if (get_sha1_hex(hex, sha1)) 98 return NULL; /* BUG */ 99 pos = sha1_pos(sha1, rerere_dir, rerere_dir_nr, rerere_dir_sha1); 100 if (pos < 0) { 101 rr_dir = xmalloc(sizeof(*rr_dir)); 102 hashcpy(rr_dir->sha1, sha1); 103 rr_dir->status = 0; 104 pos = -1 - pos; 105 106 /* Make sure the array is big enough ... */ 107 ALLOC_GROW(rerere_dir, rerere_dir_nr + 1, rerere_dir_alloc); 108 /* ... and add it in. */ 109 rerere_dir_nr++; 110 memmove(rerere_dir + pos + 1, rerere_dir + pos, 111 (rerere_dir_nr - pos - 1) * sizeof(*rerere_dir)); 112 rerere_dir[pos] = rr_dir; 113 scan_rerere_dir(rr_dir); 114 } 115 return rerere_dir[pos]; 116} 117 118static int has_rerere_resolution(const struct rerere_id *id) 119{ 120 const int both = RR_HAS_POSTIMAGE|RR_HAS_PREIMAGE; 121 122 return ((id->collection->status & both) == both); 123} 124 125static struct rerere_id *new_rerere_id_hex(char *hex) 126{ 127 struct rerere_id *id = xmalloc(sizeof(*id)); 128 id->collection = find_rerere_dir(hex); 129 return id; 130} 131 132static struct rerere_id *new_rerere_id(unsigned char *sha1) 133{ 134 return new_rerere_id_hex(sha1_to_hex(sha1)); 135} 136 137/* 138 * $GIT_DIR/MERGE_RR file is a collection of records, each of which is 139 * "conflict ID", a HT and pathname, terminated with a NUL, and is 140 * used to keep track of the set of paths that "rerere" may need to 141 * work on (i.e. what is left by the previous invocation of "git 142 * rerere" during the current conflict resolution session). 143 */ 144static void read_rr(struct string_list *rr) 145{ 146 struct strbuf buf = STRBUF_INIT; 147 FILE *in = fopen(merge_rr_path, "r"); 148 149 if (!in) 150 return; 151 while (!strbuf_getwholeline(&buf, in, '\0')) { 152 char *path; 153 unsigned char sha1[20]; 154 struct rerere_id *id; 155 156 /* There has to be the hash, tab, path and then NUL */ 157 if (buf.len < 42 || get_sha1_hex(buf.buf, sha1)) 158 die("corrupt MERGE_RR"); 159 160 if (buf.buf[40] != '\t') 161 die("corrupt MERGE_RR"); 162 buf.buf[40] = '\0'; 163 path = buf.buf + 41; 164 id = new_rerere_id_hex(buf.buf); 165 string_list_insert(rr, path)->util = id; 166 } 167 strbuf_release(&buf); 168 fclose(in); 169} 170 171static struct lock_file write_lock; 172 173static int write_rr(struct string_list *rr, int out_fd) 174{ 175 int i; 176 for (i = 0; i < rr->nr; i++) { 177 struct strbuf buf = STRBUF_INIT; 178 struct rerere_id *id; 179 180 assert(rr->items[i].util != RERERE_RESOLVED); 181 182 id = rr->items[i].util; 183 if (!id) 184 continue; 185 strbuf_addf(&buf, "%s\t%s%c", 186 rerere_id_hex(id), 187 rr->items[i].string, 0); 188 if (write_in_full(out_fd, buf.buf, buf.len) != buf.len) 189 die("unable to write rerere record"); 190 191 strbuf_release(&buf); 192 } 193 if (commit_lock_file(&write_lock) != 0) 194 die("unable to write rerere record"); 195 return 0; 196} 197 198/* 199 * "rerere" interacts with conflicted file contents using this I/O 200 * abstraction. It reads a conflicted contents from one place via 201 * "getline()" method, and optionally can write it out after 202 * normalizing the conflicted hunks to the "output". Subclasses of 203 * rerere_io embed this structure at the beginning of their own 204 * rerere_io object. 205 */ 206struct rerere_io { 207 int (*getline)(struct strbuf *, struct rerere_io *); 208 FILE *output; 209 int wrerror; 210 /* some more stuff */ 211}; 212 213static void ferr_write(const void *p, size_t count, FILE *fp, int *err) 214{ 215 if (!count || *err) 216 return; 217 if (fwrite(p, count, 1, fp) != 1) 218 *err = errno; 219} 220 221static inline void ferr_puts(const char *s, FILE *fp, int *err) 222{ 223 ferr_write(s, strlen(s), fp, err); 224} 225 226static void rerere_io_putstr(const char *str, struct rerere_io *io) 227{ 228 if (io->output) 229 ferr_puts(str, io->output, &io->wrerror); 230} 231 232/* 233 * Write a conflict marker to io->output (if defined). 234 */ 235static void rerere_io_putconflict(int ch, int size, struct rerere_io *io) 236{ 237 char buf[64]; 238 239 while (size) { 240 if (size <= sizeof(buf) - 2) { 241 memset(buf, ch, size); 242 buf[size] = '\n'; 243 buf[size + 1] = '\0'; 244 size = 0; 245 } else { 246 int sz = sizeof(buf) - 1; 247 248 /* 249 * Make sure we will not write everything out 250 * in this round by leaving at least 1 byte 251 * for the next round, giving the next round 252 * a chance to add the terminating LF. Yuck. 253 */ 254 if (size <= sz) 255 sz -= (sz - size) + 1; 256 memset(buf, ch, sz); 257 buf[sz] = '\0'; 258 size -= sz; 259 } 260 rerere_io_putstr(buf, io); 261 } 262} 263 264static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io) 265{ 266 if (io->output) 267 ferr_write(mem, sz, io->output, &io->wrerror); 268} 269 270/* 271 * Subclass of rerere_io that reads from an on-disk file 272 */ 273struct rerere_io_file { 274 struct rerere_io io; 275 FILE *input; 276}; 277 278/* 279 * ... and its getline() method implementation 280 */ 281static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_) 282{ 283 struct rerere_io_file *io = (struct rerere_io_file *)io_; 284 return strbuf_getwholeline(sb, io->input, '\n'); 285} 286 287/* 288 * Require the exact number of conflict marker letters, no more, no 289 * less, followed by SP or any whitespace 290 * (including LF). 291 */ 292static int is_cmarker(char *buf, int marker_char, int marker_size) 293{ 294 int want_sp; 295 296 /* 297 * The beginning of our version and the end of their version 298 * always are labeled like "<<<<< ours" or ">>>>> theirs", 299 * hence we set want_sp for them. Note that the version from 300 * the common ancestor in diff3-style output is not always 301 * labelled (e.g. "||||| common" is often seen but "|||||" 302 * alone is also valid), so we do not set want_sp. 303 */ 304 want_sp = (marker_char == '<') || (marker_char == '>'); 305 306 while (marker_size--) 307 if (*buf++ != marker_char) 308 return 0; 309 if (want_sp && *buf != ' ') 310 return 0; 311 return isspace(*buf); 312} 313 314/* 315 * Read contents a file with conflicts, normalize the conflicts 316 * by (1) discarding the common ancestor version in diff3-style, 317 * (2) reordering our side and their side so that whichever sorts 318 * alphabetically earlier comes before the other one, while 319 * computing the "conflict ID", which is just an SHA-1 hash of 320 * one side of the conflict, NUL, the other side of the conflict, 321 * and NUL concatenated together. 322 * 323 * Return the number of conflict hunks found. 324 * 325 * NEEDSWORK: the logic and theory of operation behind this conflict 326 * normalization may deserve to be documented somewhere, perhaps in 327 * Documentation/technical/rerere.txt. 328 */ 329static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size) 330{ 331 git_SHA_CTX ctx; 332 int hunk_no = 0; 333 enum { 334 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL 335 } hunk = RR_CONTEXT; 336 struct strbuf one = STRBUF_INIT, two = STRBUF_INIT; 337 struct strbuf buf = STRBUF_INIT; 338 339 if (sha1) 340 git_SHA1_Init(&ctx); 341 342 while (!io->getline(&buf, io)) { 343 if (is_cmarker(buf.buf, '<', marker_size)) { 344 if (hunk != RR_CONTEXT) 345 goto bad; 346 hunk = RR_SIDE_1; 347 } else if (is_cmarker(buf.buf, '|', marker_size)) { 348 if (hunk != RR_SIDE_1) 349 goto bad; 350 hunk = RR_ORIGINAL; 351 } else if (is_cmarker(buf.buf, '=', marker_size)) { 352 if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL) 353 goto bad; 354 hunk = RR_SIDE_2; 355 } else if (is_cmarker(buf.buf, '>', marker_size)) { 356 if (hunk != RR_SIDE_2) 357 goto bad; 358 if (strbuf_cmp(&one, &two) > 0) 359 strbuf_swap(&one, &two); 360 hunk_no++; 361 hunk = RR_CONTEXT; 362 rerere_io_putconflict('<', marker_size, io); 363 rerere_io_putmem(one.buf, one.len, io); 364 rerere_io_putconflict('=', marker_size, io); 365 rerere_io_putmem(two.buf, two.len, io); 366 rerere_io_putconflict('>', marker_size, io); 367 if (sha1) { 368 git_SHA1_Update(&ctx, one.buf ? one.buf : "", 369 one.len + 1); 370 git_SHA1_Update(&ctx, two.buf ? two.buf : "", 371 two.len + 1); 372 } 373 strbuf_reset(&one); 374 strbuf_reset(&two); 375 } else if (hunk == RR_SIDE_1) 376 strbuf_addbuf(&one, &buf); 377 else if (hunk == RR_ORIGINAL) 378 ; /* discard */ 379 else if (hunk == RR_SIDE_2) 380 strbuf_addbuf(&two, &buf); 381 else 382 rerere_io_putstr(buf.buf, io); 383 continue; 384 bad: 385 hunk = 99; /* force error exit */ 386 break; 387 } 388 strbuf_release(&one); 389 strbuf_release(&two); 390 strbuf_release(&buf); 391 392 if (sha1) 393 git_SHA1_Final(sha1, &ctx); 394 if (hunk != RR_CONTEXT) 395 return -1; 396 return hunk_no; 397} 398 399/* 400 * Scan the path for conflicts, do the "handle_path()" thing above, and 401 * return the number of conflict hunks found. 402 */ 403static int handle_file(const char *path, unsigned char *sha1, const char *output) 404{ 405 int hunk_no = 0; 406 struct rerere_io_file io; 407 int marker_size = ll_merge_marker_size(path); 408 409 memset(&io, 0, sizeof(io)); 410 io.io.getline = rerere_file_getline; 411 io.input = fopen(path, "r"); 412 io.io.wrerror = 0; 413 if (!io.input) 414 return error("Could not open %s", path); 415 416 if (output) { 417 io.io.output = fopen(output, "w"); 418 if (!io.io.output) { 419 fclose(io.input); 420 return error("Could not write %s", output); 421 } 422 } 423 424 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size); 425 426 fclose(io.input); 427 if (io.io.wrerror) 428 error("There were errors while writing %s (%s)", 429 path, strerror(io.io.wrerror)); 430 if (io.io.output && fclose(io.io.output)) 431 io.io.wrerror = error("Failed to flush %s: %s", 432 path, strerror(errno)); 433 434 if (hunk_no < 0) { 435 if (output) 436 unlink_or_warn(output); 437 return error("Could not parse conflict hunks in %s", path); 438 } 439 if (io.io.wrerror) 440 return -1; 441 return hunk_no; 442} 443 444/* 445 * Subclass of rerere_io that reads from an in-core buffer that is a 446 * strbuf 447 */ 448struct rerere_io_mem { 449 struct rerere_io io; 450 struct strbuf input; 451}; 452 453/* 454 * ... and its getline() method implementation 455 */ 456static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_) 457{ 458 struct rerere_io_mem *io = (struct rerere_io_mem *)io_; 459 char *ep; 460 size_t len; 461 462 strbuf_release(sb); 463 if (!io->input.len) 464 return -1; 465 ep = memchr(io->input.buf, '\n', io->input.len); 466 if (!ep) 467 ep = io->input.buf + io->input.len; 468 else if (*ep == '\n') 469 ep++; 470 len = ep - io->input.buf; 471 strbuf_add(sb, io->input.buf, len); 472 strbuf_remove(&io->input, 0, len); 473 return 0; 474} 475 476static int handle_cache(const char *path, unsigned char *sha1, const char *output) 477{ 478 mmfile_t mmfile[3] = {{NULL}}; 479 mmbuffer_t result = {NULL, 0}; 480 const struct cache_entry *ce; 481 int pos, len, i, hunk_no; 482 struct rerere_io_mem io; 483 int marker_size = ll_merge_marker_size(path); 484 485 /* 486 * Reproduce the conflicted merge in-core 487 */ 488 len = strlen(path); 489 pos = cache_name_pos(path, len); 490 if (0 <= pos) 491 return -1; 492 pos = -pos - 1; 493 494 while (pos < active_nr) { 495 enum object_type type; 496 unsigned long size; 497 498 ce = active_cache[pos++]; 499 if (ce_namelen(ce) != len || memcmp(ce->name, path, len)) 500 break; 501 i = ce_stage(ce) - 1; 502 if (!mmfile[i].ptr) { 503 mmfile[i].ptr = read_sha1_file(ce->sha1, &type, &size); 504 mmfile[i].size = size; 505 } 506 } 507 for (i = 0; i < 3; i++) 508 if (!mmfile[i].ptr && !mmfile[i].size) 509 mmfile[i].ptr = xstrdup(""); 510 511 /* 512 * NEEDSWORK: handle conflicts from merges with 513 * merge.renormalize set, too 514 */ 515 ll_merge(&result, path, &mmfile[0], NULL, 516 &mmfile[1], "ours", 517 &mmfile[2], "theirs", NULL); 518 for (i = 0; i < 3; i++) 519 free(mmfile[i].ptr); 520 521 memset(&io, 0, sizeof(io)); 522 io.io.getline = rerere_mem_getline; 523 if (output) 524 io.io.output = fopen(output, "w"); 525 else 526 io.io.output = NULL; 527 strbuf_init(&io.input, 0); 528 strbuf_attach(&io.input, result.ptr, result.size, result.size); 529 530 /* 531 * Grab the conflict ID and optionally write the original 532 * contents with conflict markers out. 533 */ 534 hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size); 535 strbuf_release(&io.input); 536 if (io.io.output) 537 fclose(io.io.output); 538 return hunk_no; 539} 540 541/* 542 * Look at a cache entry at "i" and see if it is not conflicting, 543 * conflicting and we are willing to handle, or conflicting and 544 * we are unable to handle, and return the determination in *type. 545 * Return the cache index to be looked at next, by skipping the 546 * stages we have already looked at in this invocation of this 547 * function. 548 */ 549static int check_one_conflict(int i, int *type) 550{ 551 const struct cache_entry *e = active_cache[i]; 552 553 if (!ce_stage(e)) { 554 *type = RESOLVED; 555 return i + 1; 556 } 557 558 *type = PUNTED; 559 while (ce_stage(active_cache[i]) == 1) 560 i++; 561 562 /* Only handle regular files with both stages #2 and #3 */ 563 if (i + 1 < active_nr) { 564 const struct cache_entry *e2 = active_cache[i]; 565 const struct cache_entry *e3 = active_cache[i + 1]; 566 if (ce_stage(e2) == 2 && 567 ce_stage(e3) == 3 && 568 ce_same_name(e, e3) && 569 S_ISREG(e2->ce_mode) && 570 S_ISREG(e3->ce_mode)) 571 *type = THREE_STAGED; 572 } 573 574 /* Skip the entries with the same name */ 575 while (i < active_nr && ce_same_name(e, active_cache[i])) 576 i++; 577 return i; 578} 579 580/* 581 * Scan the index and find paths that have conflicts that rerere can 582 * handle, i.e. the ones that has both stages #2 and #3. 583 * 584 * NEEDSWORK: we do not record or replay a previous "resolve by 585 * deletion" for a delete-modify conflict, as that is inherently risky 586 * without knowing what modification is being discarded. The only 587 * safe case, i.e. both side doing the deletion and modification that 588 * are identical to the previous round, might want to be handled, 589 * though. 590 */ 591static int find_conflict(struct string_list *conflict) 592{ 593 int i; 594 if (read_cache() < 0) 595 return error("Could not read index"); 596 597 for (i = 0; i < active_nr;) { 598 int conflict_type; 599 const struct cache_entry *e = active_cache[i]; 600 i = check_one_conflict(i, &conflict_type); 601 if (conflict_type == THREE_STAGED) 602 string_list_insert(conflict, (const char *)e->name); 603 } 604 return 0; 605} 606 607/* 608 * The merge_rr list is meant to hold outstanding conflicted paths 609 * that rerere could handle. Abuse the list by adding other types of 610 * entries to allow the caller to show "rerere remaining". 611 * 612 * - Conflicted paths that rerere does not handle are added 613 * - Conflicted paths that have been resolved are marked as such 614 * by storing RERERE_RESOLVED to .util field (where conflict ID 615 * is expected to be stored). 616 * 617 * Do *not* write MERGE_RR file out after calling this function. 618 * 619 * NEEDSWORK: we may want to fix the caller that implements "rerere 620 * remaining" to do this without abusing merge_rr. 621 */ 622int rerere_remaining(struct string_list *merge_rr) 623{ 624 int i; 625 if (read_cache() < 0) 626 return error("Could not read index"); 627 628 for (i = 0; i < active_nr;) { 629 int conflict_type; 630 const struct cache_entry *e = active_cache[i]; 631 i = check_one_conflict(i, &conflict_type); 632 if (conflict_type == PUNTED) 633 string_list_insert(merge_rr, (const char *)e->name); 634 else if (conflict_type == RESOLVED) { 635 struct string_list_item *it; 636 it = string_list_lookup(merge_rr, (const char *)e->name); 637 if (it != NULL) { 638 free_rerere_id(it); 639 it->util = RERERE_RESOLVED; 640 } 641 } 642 } 643 return 0; 644} 645 646/* 647 * Find the conflict identified by "id"; the change between its 648 * "preimage" (i.e. a previous contents with conflict markers) and its 649 * "postimage" (i.e. the corresponding contents with conflicts 650 * resolved) may apply cleanly to the contents stored in "path", i.e. 651 * the conflict this time around. 652 * 653 * Returns 0 for successful replay of recorded resolution, or non-zero 654 * for failure. 655 */ 656static int merge(const struct rerere_id *id, const char *path) 657{ 658 FILE *f; 659 int ret; 660 mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0}; 661 mmbuffer_t result = {NULL, 0}; 662 663 /* 664 * Normalize the conflicts in path and write it out to 665 * "thisimage" temporary file. 666 */ 667 if (handle_file(path, NULL, rerere_path(id, "thisimage")) < 0) { 668 ret = 1; 669 goto out; 670 } 671 672 if (read_mmfile(&cur, rerere_path(id, "thisimage")) || 673 read_mmfile(&base, rerere_path(id, "preimage")) || 674 read_mmfile(&other, rerere_path(id, "postimage"))) { 675 ret = 1; 676 goto out; 677 } 678 679 /* 680 * A three-way merge. Note that this honors user-customizable 681 * low-level merge driver settings. 682 */ 683 ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", NULL); 684 if (ret) 685 goto out; 686 687 /* 688 * A successful replay of recorded resolution. 689 * Mark that "postimage" was used to help gc. 690 */ 691 if (utime(rerere_path(id, "postimage"), NULL) < 0) 692 warning("failed utime() on %s: %s", 693 rerere_path(id, "postimage"), 694 strerror(errno)); 695 696 /* Update "path" with the resolution */ 697 f = fopen(path, "w"); 698 if (!f) 699 return error("Could not open %s: %s", path, 700 strerror(errno)); 701 if (fwrite(result.ptr, result.size, 1, f) != 1) 702 error("Could not write %s: %s", path, strerror(errno)); 703 if (fclose(f)) 704 return error("Writing %s failed: %s", path, 705 strerror(errno)); 706 707out: 708 free(cur.ptr); 709 free(base.ptr); 710 free(other.ptr); 711 free(result.ptr); 712 713 return ret; 714} 715 716static struct lock_file index_lock; 717 718static void update_paths(struct string_list *update) 719{ 720 int i; 721 722 hold_locked_index(&index_lock, 1); 723 724 for (i = 0; i < update->nr; i++) { 725 struct string_list_item *item = &update->items[i]; 726 if (add_file_to_cache(item->string, 0)) 727 exit(128); 728 fprintf(stderr, "Staged '%s' using previous resolution.\n", 729 item->string); 730 } 731 732 if (active_cache_changed) { 733 if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK)) 734 die("Unable to write new index file"); 735 } else 736 rollback_lock_file(&index_lock); 737} 738 739/* 740 * The path indicated by rr_item may still have conflict for which we 741 * have a recorded resolution, in which case replay it and optionally 742 * update it. Or it may have been resolved by the user and we may 743 * only have the preimage for that conflict, in which case the result 744 * needs to be recorded as a resolution in a postimage file. 745 */ 746static void do_rerere_one_path(struct string_list_item *rr_item, 747 struct string_list *update) 748{ 749 const char *path = rr_item->string; 750 const struct rerere_id *id = rr_item->util; 751 752 /* Is there a recorded resolution we could attempt to apply? */ 753 if (has_rerere_resolution(id)) { 754 if (merge(id, path)) 755 return; /* failed to replay */ 756 757 if (rerere_autoupdate) 758 string_list_insert(update, path); 759 else 760 fprintf(stderr, 761 "Resolved '%s' using previous resolution.\n", 762 path); 763 } else if (!handle_file(path, NULL, NULL)) { 764 /* The user has resolved it. */ 765 copy_file(rerere_path(id, "postimage"), path, 0666); 766 id->collection->status |= RR_HAS_POSTIMAGE; 767 fprintf(stderr, "Recorded resolution for '%s'.\n", path); 768 } else { 769 return; 770 } 771 free_rerere_id(rr_item); 772 rr_item->util = NULL; 773} 774 775static int do_plain_rerere(struct string_list *rr, int fd) 776{ 777 struct string_list conflict = STRING_LIST_INIT_DUP; 778 struct string_list update = STRING_LIST_INIT_DUP; 779 int i; 780 781 find_conflict(&conflict); 782 783 /* 784 * MERGE_RR records paths with conflicts immediately after 785 * merge failed. Some of the conflicted paths might have been 786 * hand resolved in the working tree since then, but the 787 * initial run would catch all and register their preimages. 788 */ 789 for (i = 0; i < conflict.nr; i++) { 790 struct rerere_id *id; 791 unsigned char sha1[20]; 792 const char *path = conflict.items[i].string; 793 int ret; 794 795 if (string_list_has_string(rr, path)) 796 continue; 797 798 /* 799 * Ask handle_file() to scan and assign a 800 * conflict ID. No need to write anything out 801 * yet. 802 */ 803 ret = handle_file(path, sha1, NULL); 804 if (ret < 1) 805 continue; 806 807 id = new_rerere_id(sha1); 808 string_list_insert(rr, path)->util = id; 809 810 /* 811 * Ensure that the directory exists. 812 * mkdir_in_gitdir() will fail with EEXIST if there 813 * already is one. 814 */ 815 if (mkdir_in_gitdir(rerere_path(id, NULL)) && 816 errno != EEXIST) 817 continue; /* NEEDSWORK: perhaps we should die? */ 818 819 if (id->collection->status & RR_HAS_PREIMAGE) { 820 ; 821 } else { 822 /* 823 * We are the first to encounter this 824 * conflict. Ask handle_file() to write the 825 * normalized contents to the "preimage" file. 826 * 827 * NEEDSWORK: what should happen if we had a 828 * leftover postimage that is totally 829 * unrelated? Perhaps we should unlink it? 830 */ 831 handle_file(path, NULL, rerere_path(id, "preimage")); 832 id->collection->status |= RR_HAS_PREIMAGE; 833 fprintf(stderr, "Recorded preimage for '%s'\n", path); 834 } 835 } 836 837 for (i = 0; i < rr->nr; i++) 838 do_rerere_one_path(&rr->items[i], &update); 839 840 if (update.nr) 841 update_paths(&update); 842 843 return write_rr(rr, fd); 844} 845 846static void git_rerere_config(void) 847{ 848 git_config_get_bool("rerere.enabled", &rerere_enabled); 849 git_config_get_bool("rerere.autoupdate", &rerere_autoupdate); 850 git_config(git_default_config, NULL); 851} 852 853static int is_rerere_enabled(void) 854{ 855 const char *rr_cache; 856 int rr_cache_exists; 857 858 if (!rerere_enabled) 859 return 0; 860 861 rr_cache = git_path("rr-cache"); 862 rr_cache_exists = is_directory(rr_cache); 863 if (rerere_enabled < 0) 864 return rr_cache_exists; 865 866 if (!rr_cache_exists && mkdir_in_gitdir(rr_cache)) 867 die("Could not create directory %s", rr_cache); 868 return 1; 869} 870 871int setup_rerere(struct string_list *merge_rr, int flags) 872{ 873 int fd; 874 875 git_rerere_config(); 876 if (!is_rerere_enabled()) 877 return -1; 878 879 if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE)) 880 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE); 881 merge_rr_path = git_pathdup("MERGE_RR"); 882 fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 883 LOCK_DIE_ON_ERROR); 884 read_rr(merge_rr); 885 return fd; 886} 887 888/* 889 * The main entry point that is called internally from codepaths that 890 * perform mergy operations, possibly leaving conflicted index entries 891 * and working tree files. 892 */ 893int rerere(int flags) 894{ 895 struct string_list merge_rr = STRING_LIST_INIT_DUP; 896 int fd, status; 897 898 fd = setup_rerere(&merge_rr, flags); 899 if (fd < 0) 900 return 0; 901 status = do_plain_rerere(&merge_rr, fd); 902 free_rerere_dirs(); 903 return status; 904} 905 906static int rerere_forget_one_path(const char *path, struct string_list *rr) 907{ 908 const char *filename; 909 struct rerere_id *id; 910 unsigned char sha1[20]; 911 int ret; 912 struct string_list_item *item; 913 914 /* 915 * Recreate the original conflict from the stages in the 916 * index and compute the conflict ID 917 */ 918 ret = handle_cache(path, sha1, NULL); 919 if (ret < 1) 920 return error("Could not parse conflict hunks in '%s'", path); 921 922 /* Nuke the recorded resolution for the conflict */ 923 id = new_rerere_id(sha1); 924 filename = rerere_path(id, "postimage"); 925 if (unlink(filename)) 926 return (errno == ENOENT 927 ? error("no remembered resolution for %s", path) 928 : error("cannot unlink %s: %s", filename, strerror(errno))); 929 930 /* 931 * Update the preimage so that the user can resolve the 932 * conflict in the working tree, run us again to record 933 * the postimage. 934 */ 935 handle_cache(path, sha1, rerere_path(id, "preimage")); 936 fprintf(stderr, "Updated preimage for '%s'\n", path); 937 938 /* 939 * And remember that we can record resolution for this 940 * conflict when the user is done. 941 */ 942 item = string_list_insert(rr, path); 943 free_rerere_id(item); 944 item->util = id; 945 fprintf(stderr, "Forgot resolution for %s\n", path); 946 return 0; 947} 948 949int rerere_forget(struct pathspec *pathspec) 950{ 951 int i, fd; 952 struct string_list conflict = STRING_LIST_INIT_DUP; 953 struct string_list merge_rr = STRING_LIST_INIT_DUP; 954 955 if (read_cache() < 0) 956 return error("Could not read index"); 957 958 fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE); 959 960 /* 961 * The paths may have been resolved (incorrectly); 962 * recover the original conflicted state and then 963 * find the conflicted paths. 964 */ 965 unmerge_cache(pathspec); 966 find_conflict(&conflict); 967 for (i = 0; i < conflict.nr; i++) { 968 struct string_list_item *it = &conflict.items[i]; 969 if (!match_pathspec(pathspec, it->string, 970 strlen(it->string), 0, NULL, 0)) 971 continue; 972 rerere_forget_one_path(it->string, &merge_rr); 973 } 974 return write_rr(&merge_rr, fd); 975} 976 977/* 978 * Garbage collection support 979 */ 980 981/* 982 * Note that this is not reentrant but is used only one-at-a-time 983 * so it does not matter right now. 984 */ 985static struct rerere_id *dirname_to_id(const char *name) 986{ 987 static struct rerere_id id; 988 id.collection = find_rerere_dir(name); 989 return &id; 990} 991 992static time_t rerere_created_at(const char *dir_name) 993{ 994 struct stat st; 995 struct rerere_id *id = dirname_to_id(dir_name); 996 997 return stat(rerere_path(id, "preimage"), &st) ? (time_t) 0 : st.st_mtime; 998} 9991000static time_t rerere_last_used_at(const char *dir_name)1001{1002 struct stat st;1003 struct rerere_id *id = dirname_to_id(dir_name);10041005 return stat(rerere_path(id, "postimage"), &st) ? (time_t) 0 : st.st_mtime;1006}10071008/*1009 * Remove the recorded resolution for a given conflict ID1010 */1011static void unlink_rr_item(struct rerere_id *id)1012{1013 unlink(rerere_path(id, "thisimage"));1014 unlink(rerere_path(id, "preimage"));1015 unlink(rerere_path(id, "postimage"));1016 /*1017 * NEEDSWORK: what if this rmdir() fails? Wouldn't we then1018 * assume that we already have preimage recorded in1019 * do_plain_rerere()?1020 */1021 rmdir(rerere_path(id, NULL));1022}10231024void rerere_gc(struct string_list *rr)1025{1026 struct string_list to_remove = STRING_LIST_INIT_DUP;1027 DIR *dir;1028 struct dirent *e;1029 int i, cutoff;1030 time_t now = time(NULL), then;1031 int cutoff_noresolve = 15;1032 int cutoff_resolve = 60;10331034 git_config_get_int("gc.rerereresolved", &cutoff_resolve);1035 git_config_get_int("gc.rerereunresolved", &cutoff_noresolve);1036 git_config(git_default_config, NULL);1037 dir = opendir(git_path("rr-cache"));1038 if (!dir)1039 die_errno("unable to open rr-cache directory");1040 /* Collect stale conflict IDs ... */1041 while ((e = readdir(dir))) {1042 if (is_dot_or_dotdot(e->d_name))1043 continue;10441045 then = rerere_last_used_at(e->d_name);1046 if (then) {1047 cutoff = cutoff_resolve;1048 } else {1049 then = rerere_created_at(e->d_name);1050 if (!then)1051 continue;1052 cutoff = cutoff_noresolve;1053 }1054 if (then < now - cutoff * 86400)1055 string_list_append(&to_remove, e->d_name);1056 }1057 closedir(dir);1058 /* ... and then remove them one-by-one */1059 for (i = 0; i < to_remove.nr; i++)1060 unlink_rr_item(dirname_to_id(to_remove.items[i].string));1061 string_list_clear(&to_remove, 0);1062}10631064/*1065 * During a conflict resolution, after "rerere" recorded the1066 * preimages, abandon them if the user did not resolve them or1067 * record their resolutions. And drop $GIT_DIR/MERGE_RR.1068 *1069 * NEEDSWORK: shouldn't we be calling this from "reset --hard"?1070 */1071void rerere_clear(struct string_list *merge_rr)1072{1073 int i;10741075 for (i = 0; i < merge_rr->nr; i++) {1076 struct rerere_id *id = merge_rr->items[i].util;1077 if (!has_rerere_resolution(id))1078 unlink_rr_item(id);1079 }1080 unlink_or_warn(git_path("MERGE_RR"));1081}