Andrew's git / gitweb.git / rerere.c
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rerere.con commit Documentation/technical/api-diff.txt: correct name of diff_unmerge() (7a45c31)
   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
  10#define RESOLVED 0
  11#define PUNTED 1
  12#define THREE_STAGED 2
  13void *RERERE_RESOLVED = &RERERE_RESOLVED;
  14
  15/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
  16static int rerere_enabled = -1;
  17
  18/* automatically update cleanly resolved paths to the index */
  19static int rerere_autoupdate;
  20
  21static char *merge_rr_path;
  22
  23const char *rerere_path(const char *hex, const char *file)
  24{
  25        return git_path("rr-cache/%s/%s", hex, file);
  26}
  27
  28int has_rerere_resolution(const char *hex)
  29{
  30        struct stat st;
  31        return !stat(rerere_path(hex, "postimage"), &st);
  32}
  33
  34static void read_rr(struct string_list *rr)
  35{
  36        unsigned char sha1[20];
  37        char buf[PATH_MAX];
  38        FILE *in = fopen(merge_rr_path, "r");
  39        if (!in)
  40                return;
  41        while (fread(buf, 40, 1, in) == 1) {
  42                int i;
  43                char *name;
  44                if (get_sha1_hex(buf, sha1))
  45                        die("corrupt MERGE_RR");
  46                buf[40] = '\0';
  47                name = xstrdup(buf);
  48                if (fgetc(in) != '\t')
  49                        die("corrupt MERGE_RR");
  50                for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
  51                        ; /* do nothing */
  52                if (i == sizeof(buf))
  53                        die("filename too long");
  54                string_list_insert(rr, buf)->util = name;
  55        }
  56        fclose(in);
  57}
  58
  59static struct lock_file write_lock;
  60
  61static int write_rr(struct string_list *rr, int out_fd)
  62{
  63        int i;
  64        for (i = 0; i < rr->nr; i++) {
  65                const char *path;
  66                int length;
  67                if (!rr->items[i].util)
  68                        continue;
  69                path = rr->items[i].string;
  70                length = strlen(path) + 1;
  71                if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
  72                    write_str_in_full(out_fd, "\t") != 1 ||
  73                    write_in_full(out_fd, path, length) != length)
  74                        die("unable to write rerere record");
  75        }
  76        if (commit_lock_file(&write_lock) != 0)
  77                die("unable to write rerere record");
  78        return 0;
  79}
  80
  81static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
  82{
  83        if (!count || *err)
  84                return;
  85        if (fwrite(p, count, 1, fp) != 1)
  86                *err = errno;
  87}
  88
  89static inline void ferr_puts(const char *s, FILE *fp, int *err)
  90{
  91        ferr_write(s, strlen(s), fp, err);
  92}
  93
  94struct rerere_io {
  95        int (*getline)(struct strbuf *, struct rerere_io *);
  96        FILE *output;
  97        int wrerror;
  98        /* some more stuff */
  99};
 100
 101static void rerere_io_putstr(const char *str, struct rerere_io *io)
 102{
 103        if (io->output)
 104                ferr_puts(str, io->output, &io->wrerror);
 105}
 106
 107static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
 108{
 109        char buf[64];
 110
 111        while (size) {
 112                if (size < sizeof(buf) - 2) {
 113                        memset(buf, ch, size);
 114                        buf[size] = '\n';
 115                        buf[size + 1] = '\0';
 116                        size = 0;
 117                } else {
 118                        int sz = sizeof(buf) - 1;
 119                        if (size <= sz)
 120                                sz -= (sz - size) + 1;
 121                        memset(buf, ch, sz);
 122                        buf[sz] = '\0';
 123                        size -= sz;
 124                }
 125                rerere_io_putstr(buf, io);
 126        }
 127}
 128
 129static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
 130{
 131        if (io->output)
 132                ferr_write(mem, sz, io->output, &io->wrerror);
 133}
 134
 135struct rerere_io_file {
 136        struct rerere_io io;
 137        FILE *input;
 138};
 139
 140static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
 141{
 142        struct rerere_io_file *io = (struct rerere_io_file *)io_;
 143        return strbuf_getwholeline(sb, io->input, '\n');
 144}
 145
 146static int is_cmarker(char *buf, int marker_char, int marker_size, int want_sp)
 147{
 148        while (marker_size--)
 149                if (*buf++ != marker_char)
 150                        return 0;
 151        if (want_sp && *buf != ' ')
 152                return 0;
 153        return isspace(*buf);
 154}
 155
 156static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
 157{
 158        git_SHA_CTX ctx;
 159        int hunk_no = 0;
 160        enum {
 161                RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL
 162        } hunk = RR_CONTEXT;
 163        struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
 164        struct strbuf buf = STRBUF_INIT;
 165
 166        if (sha1)
 167                git_SHA1_Init(&ctx);
 168
 169        while (!io->getline(&buf, io)) {
 170                if (is_cmarker(buf.buf, '<', marker_size, 1)) {
 171                        if (hunk != RR_CONTEXT)
 172                                goto bad;
 173                        hunk = RR_SIDE_1;
 174                } else if (is_cmarker(buf.buf, '|', marker_size, 0)) {
 175                        if (hunk != RR_SIDE_1)
 176                                goto bad;
 177                        hunk = RR_ORIGINAL;
 178                } else if (is_cmarker(buf.buf, '=', marker_size, 0)) {
 179                        if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
 180                                goto bad;
 181                        hunk = RR_SIDE_2;
 182                } else if (is_cmarker(buf.buf, '>', marker_size, 1)) {
 183                        if (hunk != RR_SIDE_2)
 184                                goto bad;
 185                        if (strbuf_cmp(&one, &two) > 0)
 186                                strbuf_swap(&one, &two);
 187                        hunk_no++;
 188                        hunk = RR_CONTEXT;
 189                        rerere_io_putconflict('<', marker_size, io);
 190                        rerere_io_putmem(one.buf, one.len, io);
 191                        rerere_io_putconflict('=', marker_size, io);
 192                        rerere_io_putmem(two.buf, two.len, io);
 193                        rerere_io_putconflict('>', marker_size, io);
 194                        if (sha1) {
 195                                git_SHA1_Update(&ctx, one.buf ? one.buf : "",
 196                                            one.len + 1);
 197                                git_SHA1_Update(&ctx, two.buf ? two.buf : "",
 198                                            two.len + 1);
 199                        }
 200                        strbuf_reset(&one);
 201                        strbuf_reset(&two);
 202                } else if (hunk == RR_SIDE_1)
 203                        strbuf_addstr(&one, buf.buf);
 204                else if (hunk == RR_ORIGINAL)
 205                        ; /* discard */
 206                else if (hunk == RR_SIDE_2)
 207                        strbuf_addstr(&two, buf.buf);
 208                else
 209                        rerere_io_putstr(buf.buf, io);
 210                continue;
 211        bad:
 212                hunk = 99; /* force error exit */
 213                break;
 214        }
 215        strbuf_release(&one);
 216        strbuf_release(&two);
 217        strbuf_release(&buf);
 218
 219        if (sha1)
 220                git_SHA1_Final(sha1, &ctx);
 221        if (hunk != RR_CONTEXT)
 222                return -1;
 223        return hunk_no;
 224}
 225
 226static int handle_file(const char *path, unsigned char *sha1, const char *output)
 227{
 228        int hunk_no = 0;
 229        struct rerere_io_file io;
 230        int marker_size = ll_merge_marker_size(path);
 231
 232        memset(&io, 0, sizeof(io));
 233        io.io.getline = rerere_file_getline;
 234        io.input = fopen(path, "r");
 235        io.io.wrerror = 0;
 236        if (!io.input)
 237                return error("Could not open %s", path);
 238
 239        if (output) {
 240                io.io.output = fopen(output, "w");
 241                if (!io.io.output) {
 242                        fclose(io.input);
 243                        return error("Could not write %s", output);
 244                }
 245        }
 246
 247        hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
 248
 249        fclose(io.input);
 250        if (io.io.wrerror)
 251                error("There were errors while writing %s (%s)",
 252                      path, strerror(io.io.wrerror));
 253        if (io.io.output && fclose(io.io.output))
 254                io.io.wrerror = error("Failed to flush %s: %s",
 255                                      path, strerror(errno));
 256
 257        if (hunk_no < 0) {
 258                if (output)
 259                        unlink_or_warn(output);
 260                return error("Could not parse conflict hunks in %s", path);
 261        }
 262        if (io.io.wrerror)
 263                return -1;
 264        return hunk_no;
 265}
 266
 267struct rerere_io_mem {
 268        struct rerere_io io;
 269        struct strbuf input;
 270};
 271
 272static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
 273{
 274        struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
 275        char *ep;
 276        size_t len;
 277
 278        strbuf_release(sb);
 279        if (!io->input.len)
 280                return -1;
 281        ep = strchrnul(io->input.buf, '\n');
 282        if (*ep == '\n')
 283                ep++;
 284        len = ep - io->input.buf;
 285        strbuf_add(sb, io->input.buf, len);
 286        strbuf_remove(&io->input, 0, len);
 287        return 0;
 288}
 289
 290static int handle_cache(const char *path, unsigned char *sha1, const char *output)
 291{
 292        mmfile_t mmfile[3];
 293        mmbuffer_t result = {NULL, 0};
 294        struct cache_entry *ce;
 295        int pos, len, i, hunk_no;
 296        struct rerere_io_mem io;
 297        int marker_size = ll_merge_marker_size(path);
 298
 299        /*
 300         * Reproduce the conflicted merge in-core
 301         */
 302        len = strlen(path);
 303        pos = cache_name_pos(path, len);
 304        if (0 <= pos)
 305                return -1;
 306        pos = -pos - 1;
 307
 308        for (i = 0; i < 3; i++) {
 309                enum object_type type;
 310                unsigned long size;
 311
 312                mmfile[i].size = 0;
 313                mmfile[i].ptr = NULL;
 314                if (active_nr <= pos)
 315                        break;
 316                ce = active_cache[pos++];
 317                if (ce_namelen(ce) != len || memcmp(ce->name, path, len)
 318                    || ce_stage(ce) != i + 1)
 319                        break;
 320                mmfile[i].ptr = read_sha1_file(ce->sha1, &type, &size);
 321                mmfile[i].size = size;
 322        }
 323        for (i = 0; i < 3; i++) {
 324                if (!mmfile[i].ptr && !mmfile[i].size)
 325                        mmfile[i].ptr = xstrdup("");
 326        }
 327        /*
 328         * NEEDSWORK: handle conflicts from merges with
 329         * merge.renormalize set, too
 330         */
 331        ll_merge(&result, path, &mmfile[0], NULL,
 332                 &mmfile[1], "ours",
 333                 &mmfile[2], "theirs", NULL);
 334        for (i = 0; i < 3; i++)
 335                free(mmfile[i].ptr);
 336
 337        memset(&io, 0, sizeof(io));
 338        io.io.getline = rerere_mem_getline;
 339        if (output)
 340                io.io.output = fopen(output, "w");
 341        else
 342                io.io.output = NULL;
 343        strbuf_init(&io.input, 0);
 344        strbuf_attach(&io.input, result.ptr, result.size, result.size);
 345
 346        hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
 347        strbuf_release(&io.input);
 348        if (io.io.output)
 349                fclose(io.io.output);
 350        return hunk_no;
 351}
 352
 353static int check_one_conflict(int i, int *type)
 354{
 355        struct cache_entry *e = active_cache[i];
 356
 357        if (!ce_stage(e)) {
 358                *type = RESOLVED;
 359                return i + 1;
 360        }
 361
 362        *type = PUNTED;
 363        if (ce_stage(e) == 1) {
 364                if (active_nr <= ++i)
 365                        return i + 1;
 366        }
 367
 368        /* Only handle regular files with both stages #2 and #3 */
 369        if (i + 1 < active_nr) {
 370                struct cache_entry *e2 = active_cache[i];
 371                struct cache_entry *e3 = active_cache[i + 1];
 372                if (ce_stage(e2) == 2 &&
 373                    ce_stage(e3) == 3 &&
 374                    ce_same_name(e, e3) &&
 375                    S_ISREG(e2->ce_mode) &&
 376                    S_ISREG(e3->ce_mode))
 377                        *type = THREE_STAGED;
 378        }
 379
 380        /* Skip the entries with the same name */
 381        while (i < active_nr && ce_same_name(e, active_cache[i]))
 382                i++;
 383        return i;
 384}
 385
 386static int find_conflict(struct string_list *conflict)
 387{
 388        int i;
 389        if (read_cache() < 0)
 390                return error("Could not read index");
 391
 392        for (i = 0; i < active_nr;) {
 393                int conflict_type;
 394                struct cache_entry *e = active_cache[i];
 395                i = check_one_conflict(i, &conflict_type);
 396                if (conflict_type == THREE_STAGED)
 397                        string_list_insert(conflict, (const char *)e->name);
 398        }
 399        return 0;
 400}
 401
 402int rerere_remaining(struct string_list *merge_rr)
 403{
 404        int i;
 405        if (read_cache() < 0)
 406                return error("Could not read index");
 407
 408        for (i = 0; i < active_nr;) {
 409                int conflict_type;
 410                struct cache_entry *e = active_cache[i];
 411                i = check_one_conflict(i, &conflict_type);
 412                if (conflict_type == PUNTED)
 413                        string_list_insert(merge_rr, (const char *)e->name);
 414                else if (conflict_type == RESOLVED) {
 415                        struct string_list_item *it;
 416                        it = string_list_lookup(merge_rr, (const char *)e->name);
 417                        if (it != NULL) {
 418                                free(it->util);
 419                                it->util = RERERE_RESOLVED;
 420                        }
 421                }
 422        }
 423        return 0;
 424}
 425
 426static int merge(const char *name, const char *path)
 427{
 428        int ret;
 429        mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
 430        mmbuffer_t result = {NULL, 0};
 431
 432        if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
 433                return 1;
 434
 435        if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
 436                        read_mmfile(&base, rerere_path(name, "preimage")) ||
 437                        read_mmfile(&other, rerere_path(name, "postimage"))) {
 438                ret = 1;
 439                goto out;
 440        }
 441        ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", NULL);
 442        if (!ret) {
 443                FILE *f;
 444
 445                if (utime(rerere_path(name, "postimage"), NULL) < 0)
 446                        warning("failed utime() on %s: %s",
 447                                        rerere_path(name, "postimage"),
 448                                        strerror(errno));
 449                f = fopen(path, "w");
 450                if (!f)
 451                        return error("Could not open %s: %s", path,
 452                                     strerror(errno));
 453                if (fwrite(result.ptr, result.size, 1, f) != 1)
 454                        error("Could not write %s: %s", path, strerror(errno));
 455                if (fclose(f))
 456                        return error("Writing %s failed: %s", path,
 457                                     strerror(errno));
 458        }
 459
 460out:
 461        free(cur.ptr);
 462        free(base.ptr);
 463        free(other.ptr);
 464        free(result.ptr);
 465
 466        return ret;
 467}
 468
 469static struct lock_file index_lock;
 470
 471static int update_paths(struct string_list *update)
 472{
 473        int i;
 474        int fd = hold_locked_index(&index_lock, 0);
 475        int status = 0;
 476
 477        if (fd < 0)
 478                return -1;
 479
 480        for (i = 0; i < update->nr; i++) {
 481                struct string_list_item *item = &update->items[i];
 482                if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
 483                        status = -1;
 484        }
 485
 486        if (!status && active_cache_changed) {
 487                if (write_cache(fd, active_cache, active_nr) ||
 488                    commit_locked_index(&index_lock))
 489                        die("Unable to write new index file");
 490        } else if (fd >= 0)
 491                rollback_lock_file(&index_lock);
 492        return status;
 493}
 494
 495static int do_plain_rerere(struct string_list *rr, int fd)
 496{
 497        struct string_list conflict = STRING_LIST_INIT_DUP;
 498        struct string_list update = STRING_LIST_INIT_DUP;
 499        int i;
 500
 501        find_conflict(&conflict);
 502
 503        /*
 504         * MERGE_RR records paths with conflicts immediately after merge
 505         * failed.  Some of the conflicted paths might have been hand resolved
 506         * in the working tree since then, but the initial run would catch all
 507         * and register their preimages.
 508         */
 509
 510        for (i = 0; i < conflict.nr; i++) {
 511                const char *path = conflict.items[i].string;
 512                if (!string_list_has_string(rr, path)) {
 513                        unsigned char sha1[20];
 514                        char *hex;
 515                        int ret;
 516                        ret = handle_file(path, sha1, NULL);
 517                        if (ret < 1)
 518                                continue;
 519                        hex = xstrdup(sha1_to_hex(sha1));
 520                        string_list_insert(rr, path)->util = hex;
 521                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 522                                continue;
 523                        handle_file(path, NULL, rerere_path(hex, "preimage"));
 524                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 525                }
 526        }
 527
 528        /*
 529         * Now some of the paths that had conflicts earlier might have been
 530         * hand resolved.  Others may be similar to a conflict already that
 531         * was resolved before.
 532         */
 533
 534        for (i = 0; i < rr->nr; i++) {
 535                int ret;
 536                const char *path = rr->items[i].string;
 537                const char *name = (const char *)rr->items[i].util;
 538
 539                if (has_rerere_resolution(name)) {
 540                        if (!merge(name, path)) {
 541                                if (rerere_autoupdate)
 542                                        string_list_insert(&update, path);
 543                                fprintf(stderr,
 544                                        "%s '%s' using previous resolution.\n",
 545                                        rerere_autoupdate
 546                                        ? "Staged" : "Resolved",
 547                                        path);
 548                                goto mark_resolved;
 549                        }
 550                }
 551
 552                /* Let's see if we have resolved it. */
 553                ret = handle_file(path, NULL, NULL);
 554                if (ret)
 555                        continue;
 556
 557                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 558                copy_file(rerere_path(name, "postimage"), path, 0666);
 559        mark_resolved:
 560                rr->items[i].util = NULL;
 561        }
 562
 563        if (update.nr)
 564                update_paths(&update);
 565
 566        return write_rr(rr, fd);
 567}
 568
 569static int git_rerere_config(const char *var, const char *value, void *cb)
 570{
 571        if (!strcmp(var, "rerere.enabled"))
 572                rerere_enabled = git_config_bool(var, value);
 573        else if (!strcmp(var, "rerere.autoupdate"))
 574                rerere_autoupdate = git_config_bool(var, value);
 575        else
 576                return git_default_config(var, value, cb);
 577        return 0;
 578}
 579
 580static int is_rerere_enabled(void)
 581{
 582        const char *rr_cache;
 583        int rr_cache_exists;
 584
 585        if (!rerere_enabled)
 586                return 0;
 587
 588        rr_cache = git_path("rr-cache");
 589        rr_cache_exists = is_directory(rr_cache);
 590        if (rerere_enabled < 0)
 591                return rr_cache_exists;
 592
 593        if (!rr_cache_exists && mkdir_in_gitdir(rr_cache))
 594                die("Could not create directory %s", rr_cache);
 595        return 1;
 596}
 597
 598int setup_rerere(struct string_list *merge_rr, int flags)
 599{
 600        int fd;
 601
 602        git_config(git_rerere_config, NULL);
 603        if (!is_rerere_enabled())
 604                return -1;
 605
 606        if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
 607                rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
 608        merge_rr_path = git_pathdup("MERGE_RR");
 609        fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
 610                                       LOCK_DIE_ON_ERROR);
 611        read_rr(merge_rr);
 612        return fd;
 613}
 614
 615int rerere(int flags)
 616{
 617        struct string_list merge_rr = STRING_LIST_INIT_DUP;
 618        int fd;
 619
 620        fd = setup_rerere(&merge_rr, flags);
 621        if (fd < 0)
 622                return 0;
 623        return do_plain_rerere(&merge_rr, fd);
 624}
 625
 626static int rerere_forget_one_path(const char *path, struct string_list *rr)
 627{
 628        const char *filename;
 629        char *hex;
 630        unsigned char sha1[20];
 631        int ret;
 632
 633        ret = handle_cache(path, sha1, NULL);
 634        if (ret < 1)
 635                return error("Could not parse conflict hunks in '%s'", path);
 636        hex = xstrdup(sha1_to_hex(sha1));
 637        filename = rerere_path(hex, "postimage");
 638        if (unlink(filename))
 639                return (errno == ENOENT
 640                        ? error("no remembered resolution for %s", path)
 641                        : error("cannot unlink %s: %s", filename, strerror(errno)));
 642
 643        handle_cache(path, sha1, rerere_path(hex, "preimage"));
 644        fprintf(stderr, "Updated preimage for '%s'\n", path);
 645
 646
 647        string_list_insert(rr, path)->util = hex;
 648        fprintf(stderr, "Forgot resolution for %s\n", path);
 649        return 0;
 650}
 651
 652int rerere_forget(const char **pathspec)
 653{
 654        int i, fd;
 655        struct string_list conflict = STRING_LIST_INIT_DUP;
 656        struct string_list merge_rr = STRING_LIST_INIT_DUP;
 657
 658        if (read_cache() < 0)
 659                return error("Could not read index");
 660
 661        fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
 662
 663        unmerge_cache(pathspec);
 664        find_conflict(&conflict);
 665        for (i = 0; i < conflict.nr; i++) {
 666                struct string_list_item *it = &conflict.items[i];
 667                if (!match_pathspec(pathspec, it->string, strlen(it->string),
 668                                    0, NULL))
 669                        continue;
 670                rerere_forget_one_path(it->string, &merge_rr);
 671        }
 672        return write_rr(&merge_rr, fd);
 673}