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 #include "pathspec.h"
  10
  11 #define RESOLVED 0
  12 #define PUNTED 1
  13 #define THREE_STAGED 2
  14 void *RERERE_RESOLVED = &RERERE_RESOLVED;
  15
  16 /* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
  17 static int rerere_enabled = -1;
  18
  19 /* automatically update cleanly resolved paths to the index */
  20 static int rerere_autoupdate;
  21
  22 static char *merge_rr_path;
  23
  24 const char *rerere_path(const char *hex, const char *file)
  25 {
  26         return git_path("rr-cache/%s/%s", hex, file);
  27 }
  28
  29 static int has_rerere_resolution(const char *hex)
  30 {
  31         struct stat st;
  32         return !stat(rerere_path(hex, "postimage"), &st);
  33 }
  34
  35 static void read_rr(struct string_list *rr)
  36 {
  37         unsigned char sha1[20];
  38         char buf[PATH_MAX];
  39         FILE *in = fopen(merge_rr_path, "r");
  40         if (!in)
  41                 return;
  42         while (fread(buf, 40, 1, in) == 1) {
  43                 int i;
  44                 char *name;
  45                 if (get_sha1_hex(buf, sha1))
  46                         die("corrupt MERGE_RR");
  47                 buf[40] = '\0';
  48                 name = xstrdup(buf);
  49                 if (fgetc(in) != '\t')
  50                         die("corrupt MERGE_RR");
  51                 for (i = 0; i < sizeof(buf); i++) {
  52                         int c = fgetc(in);
  53                         if (c < 0)
  54                                 die("corrupt MERGE_RR");
  55                         buf[i] = c;
  56                         if (c == 0)
  57                                  break;
  58                 }
  59                 if (i == sizeof(buf))
  60                         die("filename too long");
  61                 string_list_insert(rr, buf)->util = name;
  62         }
  63         fclose(in);
  64 }
  65
  66 static struct lock_file write_lock;
  67
  68 static int write_rr(struct string_list *rr, int out_fd)
  69 {
  70         int i;
  71         for (i = 0; i < rr->nr; i++) {
  72                 const char *path;
  73                 int length;
  74                 if (!rr->items[i].util)
  75                         continue;
  76                 path = rr->items[i].string;
  77                 length = strlen(path) + 1;
  78                 if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
  79                     write_str_in_full(out_fd, "\t") != 1 ||
  80                     write_in_full(out_fd, path, length) != length)
  81                         die("unable to write rerere record");
  82         }
  83         if (commit_lock_file(&write_lock) != 0)
  84                 die("unable to write rerere record");
  85         return 0;
  86 }
  87
  88 static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
  89 {
  90         if (!count || *err)
  91                 return;
  92         if (fwrite(p, count, 1, fp) != 1)
  93                 *err = errno;
  94 }
  95
  96 static inline void ferr_puts(const char *s, FILE *fp, int *err)
  97 {
  98         ferr_write(s, strlen(s), fp, err);
  99 }
 100
 101 struct rerere_io {
 102         int (*getline)(struct strbuf *, struct rerere_io *);
 103         FILE *output;
 104         int wrerror;
 105         /* some more stuff */
 106 };
 107
 108 static void rerere_io_putstr(const char *str, struct rerere_io *io)
 109 {
 110         if (io->output)
 111                 ferr_puts(str, io->output, &io->wrerror);
 112 }
 113
 114 static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
 115 {
 116         char buf[64];
 117
 118         while (size) {
 119                 if (size < sizeof(buf) - 2) {
 120                         memset(buf, ch, size);
 121                         buf[size] = '\n';
 122                         buf[size + 1] = '\0';
 123                         size = 0;
 124                 } else {
 125                         int sz = sizeof(buf) - 1;
 126                         if (size <= sz)
 127                                 sz -= (sz - size) + 1;
 128                         memset(buf, ch, sz);
 129                         buf[sz] = '\0';
 130                         size -= sz;
 131                 }
 132                 rerere_io_putstr(buf, io);
 133         }
 134 }
 135
 136 static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
 137 {
 138         if (io->output)
 139                 ferr_write(mem, sz, io->output, &io->wrerror);
 140 }
 141
 142 struct rerere_io_file {
 143         struct rerere_io io;
 144         FILE *input;
 145 };
 146
 147 static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
 148 {
 149         struct rerere_io_file *io = (struct rerere_io_file *)io_;
 150         return strbuf_getwholeline(sb, io->input, '\n');
 151 }
 152
 153 static int is_cmarker(char *buf, int marker_char, int marker_size, int want_sp)
 154 {
 155         while (marker_size--)
 156                 if (*buf++ != marker_char)
 157                         return 0;
 158         if (want_sp && *buf != ' ')
 159                 return 0;
 160         return isspace(*buf);
 161 }
 162
 163 static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
 164 {
 165         git_SHA_CTX ctx;
 166         int hunk_no = 0;
 167         enum {
 168                 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL
 169         } hunk = RR_CONTEXT;
 170         struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
 171         struct strbuf buf = STRBUF_INIT;
 172
 173         if (sha1)
 174                 git_SHA1_Init(&ctx);
 175
 176         while (!io->getline(&buf, io)) {
 177                 if (is_cmarker(buf.buf, '<', marker_size, 1)) {
 178                         if (hunk != RR_CONTEXT)
 179                                 goto bad;
 180                         hunk = RR_SIDE_1;
 181                 } else if (is_cmarker(buf.buf, '|', marker_size, 0)) {
 182                         if (hunk != RR_SIDE_1)
 183                                 goto bad;
 184                         hunk = RR_ORIGINAL;
 185                 } else if (is_cmarker(buf.buf, '=', marker_size, 0)) {
 186                         if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
 187                                 goto bad;
 188                         hunk = RR_SIDE_2;
 189                 } else if (is_cmarker(buf.buf, '>', marker_size, 1)) {
 190                         if (hunk != RR_SIDE_2)
 191                                 goto bad;
 192                         if (strbuf_cmp(&one, &two) > 0)
 193                                 strbuf_swap(&one, &two);
 194                         hunk_no++;
 195                         hunk = RR_CONTEXT;
 196                         rerere_io_putconflict('<', marker_size, io);
 197                         rerere_io_putmem(one.buf, one.len, io);
 198                         rerere_io_putconflict('=', marker_size, io);
 199                         rerere_io_putmem(two.buf, two.len, io);
 200                         rerere_io_putconflict('>', marker_size, io);
 201                         if (sha1) {
 202                                 git_SHA1_Update(&ctx, one.buf ? one.buf : "",
 203                                             one.len + 1);
 204                                 git_SHA1_Update(&ctx, two.buf ? two.buf : "",
 205                                             two.len + 1);
 206                         }
 207                         strbuf_reset(&one);
 208                         strbuf_reset(&two);
 209                 } else if (hunk == RR_SIDE_1)
 210                         strbuf_addstr(&one, buf.buf);
 211                 else if (hunk == RR_ORIGINAL)
 212                         ; /* discard */
 213                 else if (hunk == RR_SIDE_2)
 214                         strbuf_addstr(&two, buf.buf);
 215                 else
 216                         rerere_io_putstr(buf.buf, io);
 217                 continue;
 218         bad:
 219                 hunk = 99; /* force error exit */
 220                 break;
 221         }
 222         strbuf_release(&one);
 223         strbuf_release(&two);
 224         strbuf_release(&buf);
 225
 226         if (sha1)
 227                 git_SHA1_Final(sha1, &ctx);
 228         if (hunk != RR_CONTEXT)
 229                 return -1;
 230         return hunk_no;
 231 }
 232
 233 static int handle_file(const char *path, unsigned char *sha1, const char *output)
 234 {
 235         int hunk_no = 0;
 236         struct rerere_io_file io;
 237         int marker_size = ll_merge_marker_size(path);
 238
 239         memset(&io, 0, sizeof(io));
 240         io.io.getline = rerere_file_getline;
 241         io.input = fopen(path, "r");
 242         io.io.wrerror = 0;
 243         if (!io.input)
 244                 return error("Could not open %s", path);
 245
 246         if (output) {
 247                 io.io.output = fopen(output, "w");
 248                 if (!io.io.output) {
 249                         fclose(io.input);
 250                         return error("Could not write %s", output);
 251                 }
 252         }
 253
 254         hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
 255
 256         fclose(io.input);
 257         if (io.io.wrerror)
 258                 error("There were errors while writing %s (%s)",
 259                       path, strerror(io.io.wrerror));
 260         if (io.io.output && fclose(io.io.output))
 261                 io.io.wrerror = error("Failed to flush %s: %s",
 262                                       path, strerror(errno));
 263
 264         if (hunk_no < 0) {
 265                 if (output)
 266                         unlink_or_warn(output);
 267                 return error("Could not parse conflict hunks in %s", path);
 268         }
 269         if (io.io.wrerror)
 270                 return -1;
 271         return hunk_no;
 272 }
 273
 274 struct rerere_io_mem {
 275         struct rerere_io io;
 276         struct strbuf input;
 277 };
 278
 279 static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
 280 {
 281         struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
 282         char *ep;
 283         size_t len;
 284
 285         strbuf_release(sb);
 286         if (!io->input.len)
 287                 return -1;
 288         ep = memchr(io->input.buf, '\n', io->input.len);
 289         if (!ep)
 290                 ep = io->input.buf + io->input.len;
 291         else if (*ep == '\n')
 292                 ep++;
 293         len = ep - io->input.buf;
 294         strbuf_add(sb, io->input.buf, len);
 295         strbuf_remove(&io->input, 0, len);
 296         return 0;
 297 }
 298
 299 static int handle_cache(const char *path, unsigned char *sha1, const char *output)
 300 {
 301         mmfile_t mmfile[3] = {{NULL}};
 302         mmbuffer_t result = {NULL, 0};
 303         struct cache_entry *ce;
 304         int pos, len, i, hunk_no;
 305         struct rerere_io_mem io;
 306         int marker_size = ll_merge_marker_size(path);
 307
 308         /*
 309          * Reproduce the conflicted merge in-core
 310          */
 311         len = strlen(path);
 312         pos = cache_name_pos(path, len);
 313         if (0 <= pos)
 314                 return -1;
 315         pos = -pos - 1;
 316
 317         for (i = 0; i < 3; i++) {
 318                 enum object_type type;
 319                 unsigned long size;
 320                 int j;
 321
 322                 if (active_nr <= pos)
 323                         break;
 324                 ce = active_cache[pos++];
 325                 if (ce_namelen(ce) != len || memcmp(ce->name, path, len))
 326                         continue;
 327                 j = ce_stage(ce) - 1;
 328                 mmfile[j].ptr = read_sha1_file(ce->sha1, &type, &size);
 329                 mmfile[j].size = size;
 330         }
 331         for (i = 0; i < 3; i++) {
 332                 if (!mmfile[i].ptr && !mmfile[i].size)
 333                         mmfile[i].ptr = xstrdup("");
 334         }
 335         /*
 336          * NEEDSWORK: handle conflicts from merges with
 337          * merge.renormalize set, too
 338          */
 339         ll_merge(&result, path, &mmfile[0], NULL,
 340                  &mmfile[1], "ours",
 341                  &mmfile[2], "theirs", NULL);
 342         for (i = 0; i < 3; i++)
 343                 free(mmfile[i].ptr);
 344
 345         memset(&io, 0, sizeof(io));
 346         io.io.getline = rerere_mem_getline;
 347         if (output)
 348                 io.io.output = fopen(output, "w");
 349         else
 350                 io.io.output = NULL;
 351         strbuf_init(&io.input, 0);
 352         strbuf_attach(&io.input, result.ptr, result.size, result.size);
 353
 354         hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
 355         strbuf_release(&io.input);
 356         if (io.io.output)
 357                 fclose(io.io.output);
 358         return hunk_no;
 359 }
 360
 361 static int check_one_conflict(int i, int *type)
 362 {
 363         struct cache_entry *e = active_cache[i];
 364
 365         if (!ce_stage(e)) {
 366                 *type = RESOLVED;
 367                 return i + 1;
 368         }
 369
 370         *type = PUNTED;
 371         if (ce_stage(e) == 1) {
 372                 if (active_nr <= ++i)
 373                         return i + 1;
 374         }
 375
 376         /* Only handle regular files with both stages #2 and #3 */
 377         if (i + 1 < active_nr) {
 378                 struct cache_entry *e2 = active_cache[i];
 379                 struct cache_entry *e3 = active_cache[i + 1];
 380                 if (ce_stage(e2) == 2 &&
 381                     ce_stage(e3) == 3 &&
 382                     ce_same_name(e, e3) &&
 383                     S_ISREG(e2->ce_mode) &&
 384                     S_ISREG(e3->ce_mode))
 385                         *type = THREE_STAGED;
 386         }
 387
 388         /* Skip the entries with the same name */
 389         while (i < active_nr && ce_same_name(e, active_cache[i]))
 390                 i++;
 391         return i;
 392 }
 393
 394 static int find_conflict(struct string_list *conflict)
 395 {
 396         int i;
 397         if (read_cache() < 0)
 398                 return error("Could not read index");
 399
 400         for (i = 0; i < active_nr;) {
 401                 int conflict_type;
 402                 struct cache_entry *e = active_cache[i];
 403                 i = check_one_conflict(i, &conflict_type);
 404                 if (conflict_type == THREE_STAGED)
 405                         string_list_insert(conflict, (const char *)e->name);
 406         }
 407         return 0;
 408 }
 409
 410 int rerere_remaining(struct string_list *merge_rr)
 411 {
 412         int i;
 413         if (read_cache() < 0)
 414                 return error("Could not read index");
 415
 416         for (i = 0; i < active_nr;) {
 417                 int conflict_type;
 418                 struct cache_entry *e = active_cache[i];
 419                 i = check_one_conflict(i, &conflict_type);
 420                 if (conflict_type == PUNTED)
 421                         string_list_insert(merge_rr, (const char *)e->name);
 422                 else if (conflict_type == RESOLVED) {
 423                         struct string_list_item *it;
 424                         it = string_list_lookup(merge_rr, (const char *)e->name);
 425                         if (it != NULL) {
 426                                 free(it->util);
 427                                 it->util = RERERE_RESOLVED;
 428                         }
 429                 }
 430         }
 431         return 0;
 432 }
 433
 434 static int merge(const char *name, const char *path)
 435 {
 436         int ret;
 437         mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
 438         mmbuffer_t result = {NULL, 0};
 439
 440         if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
 441                 return 1;
 442
 443         if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
 444                         read_mmfile(&base, rerere_path(name, "preimage")) ||
 445                         read_mmfile(&other, rerere_path(name, "postimage"))) {
 446                 ret = 1;
 447                 goto out;
 448         }
 449         ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", NULL);
 450         if (!ret) {
 451                 FILE *f;
 452
 453                 if (utime(rerere_path(name, "postimage"), NULL) < 0)
 454                         warning("failed utime() on %s: %s",
 455                                         rerere_path(name, "postimage"),
 456                                         strerror(errno));
 457                 f = fopen(path, "w");
 458                 if (!f)
 459                         return error("Could not open %s: %s", path,
 460                                      strerror(errno));
 461                 if (fwrite(result.ptr, result.size, 1, f) != 1)
 462                         error("Could not write %s: %s", path, strerror(errno));
 463                 if (fclose(f))
 464                         return error("Writing %s failed: %s", path,
 465                                      strerror(errno));
 466         }
 467
 468 out:
 469         free(cur.ptr);
 470         free(base.ptr);
 471         free(other.ptr);
 472         free(result.ptr);
 473
 474         return ret;
 475 }
 476
 477 static struct lock_file index_lock;
 478
 479 static int update_paths(struct string_list *update)
 480 {
 481         int i;
 482         int fd = hold_locked_index(&index_lock, 0);
 483         int status = 0;
 484
 485         if (fd < 0)
 486                 return -1;
 487
 488         for (i = 0; i < update->nr; i++) {
 489                 struct string_list_item *item = &update->items[i];
 490                 if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
 491                         status = -1;
 492         }
 493
 494         if (!status && active_cache_changed) {
 495                 if (write_cache(fd, active_cache, active_nr) ||
 496                     commit_locked_index(&index_lock))
 497                         die("Unable to write new index file");
 498         } else if (fd >= 0)
 499                 rollback_lock_file(&index_lock);
 500         return status;
 501 }
 502
 503 static int do_plain_rerere(struct string_list *rr, int fd)
 504 {
 505         struct string_list conflict = STRING_LIST_INIT_DUP;
 506         struct string_list update = STRING_LIST_INIT_DUP;
 507         int i;
 508
 509         find_conflict(&conflict);
 510
 511         /*
 512          * MERGE_RR records paths with conflicts immediately after merge
 513          * failed.  Some of the conflicted paths might have been hand resolved
 514          * in the working tree since then, but the initial run would catch all
 515          * and register their preimages.
 516          */
 517
 518         for (i = 0; i < conflict.nr; i++) {
 519                 const char *path = conflict.items[i].string;
 520                 if (!string_list_has_string(rr, path)) {
 521                         unsigned char sha1[20];
 522                         char *hex;
 523                         int ret;
 524                         ret = handle_file(path, sha1, NULL);
 525                         if (ret < 1)
 526                                 continue;
 527                         hex = xstrdup(sha1_to_hex(sha1));
 528                         string_list_insert(rr, path)->util = hex;
 529                         if (mkdir_in_gitdir(git_path("rr-cache/%s", hex)))
 530                                 continue;
 531                         handle_file(path, NULL, rerere_path(hex, "preimage"));
 532                         fprintf(stderr, "Recorded preimage for '%s'\n", path);
 533                 }
 534         }
 535
 536         /*
 537          * Now some of the paths that had conflicts earlier might have been
 538          * hand resolved.  Others may be similar to a conflict already that
 539          * was resolved before.
 540          */
 541
 542         for (i = 0; i < rr->nr; i++) {
 543                 int ret;
 544                 const char *path = rr->items[i].string;
 545                 const char *name = (const char *)rr->items[i].util;
 546
 547                 if (has_rerere_resolution(name)) {
 548                         if (!merge(name, path)) {
 549                                 const char *msg;
 550                                 if (rerere_autoupdate) {
 551                                         string_list_insert(&update, path);
 552                                         msg = "Staged '%s' using previous resolution.\n";
 553                                 } else
 554                                         msg = "Resolved '%s' using previous resolution.\n";
 555                                 fprintf(stderr, msg, path);
 556                                 goto mark_resolved;
 557                         }
 558                 }
 559
 560                 /* Let's see if we have resolved it. */
 561                 ret = handle_file(path, NULL, NULL);
 562                 if (ret)
 563                         continue;
 564
 565                 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 566                 copy_file(rerere_path(name, "postimage"), path, 0666);
 567         mark_resolved:
 568                 rr->items[i].util = NULL;
 569         }
 570
 571         if (update.nr)
 572                 update_paths(&update);
 573
 574         return write_rr(rr, fd);
 575 }
 576
 577 static int git_rerere_config(const char *var, const char *value, void *cb)
 578 {
 579         if (!strcmp(var, "rerere.enabled"))
 580                 rerere_enabled = git_config_bool(var, value);
 581         else if (!strcmp(var, "rerere.autoupdate"))
 582                 rerere_autoupdate = git_config_bool(var, value);
 583         else
 584                 return git_default_config(var, value, cb);
 585         return 0;
 586 }
 587
 588 static int is_rerere_enabled(void)
 589 {
 590         const char *rr_cache;
 591         int rr_cache_exists;
 592
 593         if (!rerere_enabled)
 594                 return 0;
 595
 596         rr_cache = git_path("rr-cache");
 597         rr_cache_exists = is_directory(rr_cache);
 598         if (rerere_enabled < 0)
 599                 return rr_cache_exists;
 600
 601         if (!rr_cache_exists && mkdir_in_gitdir(rr_cache))
 602                 die("Could not create directory %s", rr_cache);
 603         return 1;
 604 }
 605
 606 int setup_rerere(struct string_list *merge_rr, int flags)
 607 {
 608         int fd;
 609
 610         git_config(git_rerere_config, NULL);
 611         if (!is_rerere_enabled())
 612                 return -1;
 613
 614         if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
 615                 rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
 616         merge_rr_path = git_pathdup("MERGE_RR");
 617         fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
 618                                        LOCK_DIE_ON_ERROR);
 619         read_rr(merge_rr);
 620         return fd;
 621 }
 622
 623 int rerere(int flags)
 624 {
 625         struct string_list merge_rr = STRING_LIST_INIT_DUP;
 626         int fd;
 627
 628         fd = setup_rerere(&merge_rr, flags);
 629         if (fd < 0)
 630                 return 0;
 631         return do_plain_rerere(&merge_rr, fd);
 632 }
 633
 634 static int rerere_forget_one_path(const char *path, struct string_list *rr)
 635 {
 636         const char *filename;
 637         char *hex;
 638         unsigned char sha1[20];
 639         int ret;
 640
 641         ret = handle_cache(path, sha1, NULL);
 642         if (ret < 1)
 643                 return error("Could not parse conflict hunks in '%s'", path);
 644         hex = xstrdup(sha1_to_hex(sha1));
 645         filename = rerere_path(hex, "postimage");
 646         if (unlink(filename))
 647                 return (errno == ENOENT
 648                         ? error("no remembered resolution for %s", path)
 649                         : error("cannot unlink %s: %s", filename, strerror(errno)));
 650
 651         handle_cache(path, sha1, rerere_path(hex, "preimage"));
 652         fprintf(stderr, "Updated preimage for '%s'\n", path);
 653
 654
 655         string_list_insert(rr, path)->util = hex;
 656         fprintf(stderr, "Forgot resolution for %s\n", path);
 657         return 0;
 658 }
 659
 660 int rerere_forget(struct pathspec *pathspec)
 661 {
 662         int i, fd;
 663         struct string_list conflict = STRING_LIST_INIT_DUP;
 664         struct string_list merge_rr = STRING_LIST_INIT_DUP;
 665
 666         if (read_cache() < 0)
 667                 return error("Could not read index");
 668
 669         fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
 670
 671         unmerge_cache(pathspec);
 672         find_conflict(&conflict);
 673         for (i = 0; i < conflict.nr; i++) {
 674                 struct string_list_item *it = &conflict.items[i];
 675                 if (!match_pathspec_depth(pathspec, it->string, strlen(it->string),
 676                                           0, NULL))
 677                         continue;
 678                 rerere_forget_one_path(it->string, &merge_rr);
 679         }
 680         return write_rr(&merge_rr, fd);
 681 }
 682
 683 static time_t rerere_created_at(const char *name)
 684 {
 685         struct stat st;
 686         return stat(rerere_path(name, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
 687 }
 688
 689 static time_t rerere_last_used_at(const char *name)
 690 {
 691         struct stat st;
 692         return stat(rerere_path(name, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
 693 }
 694
 695 static void unlink_rr_item(const char *name)
 696 {
 697         unlink(rerere_path(name, "thisimage"));
 698         unlink(rerere_path(name, "preimage"));
 699         unlink(rerere_path(name, "postimage"));
 700         rmdir(git_path("rr-cache/%s", name));
 701 }
 702
 703 struct rerere_gc_config_cb {
 704         int cutoff_noresolve;
 705         int cutoff_resolve;
 706 };
 707
 708 static int git_rerere_gc_config(const char *var, const char *value, void *cb)
 709 {
 710         struct rerere_gc_config_cb *cf = cb;
 711
 712         if (!strcmp(var, "gc.rerereresolved"))
 713                 cf->cutoff_resolve = git_config_int(var, value);
 714         else if (!strcmp(var, "gc.rerereunresolved"))
 715                 cf->cutoff_noresolve = git_config_int(var, value);
 716         else
 717                 return git_default_config(var, value, cb);
 718         return 0;
 719 }
 720
 721 void rerere_gc(struct string_list *rr)
 722 {
 723         struct string_list to_remove = STRING_LIST_INIT_DUP;
 724         DIR *dir;
 725         struct dirent *e;
 726         int i, cutoff;
 727         time_t now = time(NULL), then;
 728         struct rerere_gc_config_cb cf = { 15, 60 };
 729
 730         git_config(git_rerere_gc_config, &cf);
 731         dir = opendir(git_path("rr-cache"));
 732         if (!dir)
 733                 die_errno("unable to open rr-cache directory");
 734         while ((e = readdir(dir))) {
 735                 if (is_dot_or_dotdot(e->d_name))
 736                         continue;
 737
 738                 then = rerere_last_used_at(e->d_name);
 739                 if (then) {
 740                         cutoff = cf.cutoff_resolve;
 741                 } else {
 742                         then = rerere_created_at(e->d_name);
 743                         if (!then)
 744                                 continue;
 745                         cutoff = cf.cutoff_noresolve;
 746                 }
 747                 if (then < now - cutoff * 86400)
 748                         string_list_append(&to_remove, e->d_name);
 749         }
 750         closedir(dir);
 751         for (i = 0; i < to_remove.nr; i++)
 752                 unlink_rr_item(to_remove.items[i].string);
 753         string_list_clear(&to_remove, 0);
 754 }
 755
 756 void rerere_clear(struct string_list *merge_rr)
 757 {
 758         int i;
 759
 760         for (i = 0; i < merge_rr->nr; i++) {
 761                 const char *name = (const char *)merge_rr->items[i].util;
 762                 if (!has_rerere_resolution(name))
 763                         unlink_rr_item(name);
 764         }
 765         unlink_or_warn(git_path("MERGE_RR"));
 766 }