Andrew's git / gitweb.git / rerere.c
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rerere.con commit Merge branch 'ag/maint-apply-too-large-p' (df91d0e)
   1#include "cache.h"
   2#include "string-list.h"
   3#include "rerere.h"
   4#include "xdiff/xdiff.h"
   5#include "xdiff-interface.h"
   6#include "dir.h"
   7#include "resolve-undo.h"
   8#include "ll-merge.h"
   9
  10/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
  11static int rerere_enabled = -1;
  12
  13/* automatically update cleanly resolved paths to the index */
  14static int rerere_autoupdate;
  15
  16static char *merge_rr_path;
  17
  18const char *rerere_path(const char *hex, const char *file)
  19{
  20        return git_path("rr-cache/%s/%s", hex, file);
  21}
  22
  23int has_rerere_resolution(const char *hex)
  24{
  25        struct stat st;
  26        return !stat(rerere_path(hex, "postimage"), &st);
  27}
  28
  29static void read_rr(struct string_list *rr)
  30{
  31        unsigned char sha1[20];
  32        char buf[PATH_MAX];
  33        FILE *in = fopen(merge_rr_path, "r");
  34        if (!in)
  35                return;
  36        while (fread(buf, 40, 1, in) == 1) {
  37                int i;
  38                char *name;
  39                if (get_sha1_hex(buf, sha1))
  40                        die("corrupt MERGE_RR");
  41                buf[40] = '\0';
  42                name = xstrdup(buf);
  43                if (fgetc(in) != '\t')
  44                        die("corrupt MERGE_RR");
  45                for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
  46                        ; /* do nothing */
  47                if (i == sizeof(buf))
  48                        die("filename too long");
  49                string_list_insert(buf, rr)->util = name;
  50        }
  51        fclose(in);
  52}
  53
  54static struct lock_file write_lock;
  55
  56static int write_rr(struct string_list *rr, int out_fd)
  57{
  58        int i;
  59        for (i = 0; i < rr->nr; i++) {
  60                const char *path;
  61                int length;
  62                if (!rr->items[i].util)
  63                        continue;
  64                path = rr->items[i].string;
  65                length = strlen(path) + 1;
  66                if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
  67                    write_str_in_full(out_fd, "\t") != 1 ||
  68                    write_in_full(out_fd, path, length) != length)
  69                        die("unable to write rerere record");
  70        }
  71        if (commit_lock_file(&write_lock) != 0)
  72                die("unable to write rerere record");
  73        return 0;
  74}
  75
  76static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
  77{
  78        if (!count || *err)
  79                return;
  80        if (fwrite(p, count, 1, fp) != 1)
  81                *err = errno;
  82}
  83
  84static inline void ferr_puts(const char *s, FILE *fp, int *err)
  85{
  86        ferr_write(s, strlen(s), fp, err);
  87}
  88
  89struct rerere_io {
  90        int (*getline)(struct strbuf *, struct rerere_io *);
  91        FILE *output;
  92        int wrerror;
  93        /* some more stuff */
  94};
  95
  96static void rerere_io_putstr(const char *str, struct rerere_io *io)
  97{
  98        if (io->output)
  99                ferr_puts(str, io->output, &io->wrerror);
 100}
 101
 102static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
 103{
 104        if (io->output)
 105                ferr_write(mem, sz, io->output, &io->wrerror);
 106}
 107
 108struct rerere_io_file {
 109        struct rerere_io io;
 110        FILE *input;
 111};
 112
 113static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
 114{
 115        struct rerere_io_file *io = (struct rerere_io_file *)io_;
 116        return strbuf_getwholeline(sb, io->input, '\n');
 117}
 118
 119static int handle_path(unsigned char *sha1, struct rerere_io *io)
 120{
 121        git_SHA_CTX ctx;
 122        int hunk_no = 0;
 123        enum {
 124                RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL,
 125        } hunk = RR_CONTEXT;
 126        struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
 127        struct strbuf buf = STRBUF_INIT;
 128
 129        if (sha1)
 130                git_SHA1_Init(&ctx);
 131
 132        while (!io->getline(&buf, io)) {
 133                if (!prefixcmp(buf.buf, "<<<<<<< ")) {
 134                        if (hunk != RR_CONTEXT)
 135                                goto bad;
 136                        hunk = RR_SIDE_1;
 137                } else if (!prefixcmp(buf.buf, "|||||||") && isspace(buf.buf[7])) {
 138                        if (hunk != RR_SIDE_1)
 139                                goto bad;
 140                        hunk = RR_ORIGINAL;
 141                } else if (!prefixcmp(buf.buf, "=======") && isspace(buf.buf[7])) {
 142                        if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
 143                                goto bad;
 144                        hunk = RR_SIDE_2;
 145                } else if (!prefixcmp(buf.buf, ">>>>>>> ")) {
 146                        if (hunk != RR_SIDE_2)
 147                                goto bad;
 148                        if (strbuf_cmp(&one, &two) > 0)
 149                                strbuf_swap(&one, &two);
 150                        hunk_no++;
 151                        hunk = RR_CONTEXT;
 152                        rerere_io_putstr("<<<<<<<\n", io);
 153                        rerere_io_putmem(one.buf, one.len, io);
 154                        rerere_io_putstr("=======\n", io);
 155                        rerere_io_putmem(two.buf, two.len, io);
 156                        rerere_io_putstr(">>>>>>>\n", io);
 157                        if (sha1) {
 158                                git_SHA1_Update(&ctx, one.buf ? one.buf : "",
 159                                            one.len + 1);
 160                                git_SHA1_Update(&ctx, two.buf ? two.buf : "",
 161                                            two.len + 1);
 162                        }
 163                        strbuf_reset(&one);
 164                        strbuf_reset(&two);
 165                } else if (hunk == RR_SIDE_1)
 166                        strbuf_addstr(&one, buf.buf);
 167                else if (hunk == RR_ORIGINAL)
 168                        ; /* discard */
 169                else if (hunk == RR_SIDE_2)
 170                        strbuf_addstr(&two, buf.buf);
 171                else
 172                        rerere_io_putstr(buf.buf, io);
 173                continue;
 174        bad:
 175                hunk = 99; /* force error exit */
 176                break;
 177        }
 178        strbuf_release(&one);
 179        strbuf_release(&two);
 180        strbuf_release(&buf);
 181
 182        if (sha1)
 183                git_SHA1_Final(sha1, &ctx);
 184        if (hunk != RR_CONTEXT)
 185                return -1;
 186        return hunk_no;
 187}
 188
 189static int handle_file(const char *path, unsigned char *sha1, const char *output)
 190{
 191        int hunk_no = 0;
 192        struct rerere_io_file io;
 193
 194        memset(&io, 0, sizeof(io));
 195        io.io.getline = rerere_file_getline;
 196        io.input = fopen(path, "r");
 197        io.io.wrerror = 0;
 198        if (!io.input)
 199                return error("Could not open %s", path);
 200
 201        if (output) {
 202                io.io.output = fopen(output, "w");
 203                if (!io.io.output) {
 204                        fclose(io.input);
 205                        return error("Could not write %s", output);
 206                }
 207        }
 208
 209        hunk_no = handle_path(sha1, (struct rerere_io *)&io);
 210
 211        fclose(io.input);
 212        if (io.io.wrerror)
 213                error("There were errors while writing %s (%s)",
 214                      path, strerror(io.io.wrerror));
 215        if (io.io.output && fclose(io.io.output))
 216                io.io.wrerror = error("Failed to flush %s: %s",
 217                                      path, strerror(errno));
 218
 219        if (hunk_no < 0) {
 220                if (output)
 221                        unlink_or_warn(output);
 222                return error("Could not parse conflict hunks in %s", path);
 223        }
 224        if (io.io.wrerror)
 225                return -1;
 226        return hunk_no;
 227}
 228
 229struct rerere_io_mem {
 230        struct rerere_io io;
 231        struct strbuf input;
 232};
 233
 234static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
 235{
 236        struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
 237        char *ep;
 238        size_t len;
 239
 240        strbuf_release(sb);
 241        if (!io->input.len)
 242                return -1;
 243        ep = strchrnul(io->input.buf, '\n');
 244        if (*ep == '\n')
 245                ep++;
 246        len = ep - io->input.buf;
 247        strbuf_add(sb, io->input.buf, len);
 248        strbuf_remove(&io->input, 0, len);
 249        return 0;
 250}
 251
 252static int handle_cache(const char *path, unsigned char *sha1, const char *output)
 253{
 254        mmfile_t mmfile[3];
 255        mmbuffer_t result = {NULL, 0};
 256        struct cache_entry *ce;
 257        int pos, len, i, hunk_no;
 258        struct rerere_io_mem io;
 259
 260        /*
 261         * Reproduce the conflicted merge in-core
 262         */
 263        len = strlen(path);
 264        pos = cache_name_pos(path, len);
 265        if (0 <= pos)
 266                return -1;
 267        pos = -pos - 1;
 268
 269        for (i = 0; i < 3; i++) {
 270                enum object_type type;
 271                unsigned long size;
 272
 273                mmfile[i].size = 0;
 274                mmfile[i].ptr = NULL;
 275                if (active_nr <= pos)
 276                        break;
 277                ce = active_cache[pos++];
 278                if (ce_namelen(ce) != len || memcmp(ce->name, path, len)
 279                    || ce_stage(ce) != i + 1)
 280                        break;
 281                mmfile[i].ptr = read_sha1_file(ce->sha1, &type, &size);
 282                mmfile[i].size = size;
 283        }
 284        for (i = 0; i < 3; i++) {
 285                if (!mmfile[i].ptr && !mmfile[i].size)
 286                        mmfile[i].ptr = xstrdup("");
 287        }
 288        ll_merge(&result, path, &mmfile[0],
 289                 &mmfile[1], "ours",
 290                 &mmfile[2], "theirs", 0);
 291        for (i = 0; i < 3; i++)
 292                free(mmfile[i].ptr);
 293
 294        memset(&io, 0, sizeof(&io));
 295        io.io.getline = rerere_mem_getline;
 296        if (output)
 297                io.io.output = fopen(output, "w");
 298        else
 299                io.io.output = NULL;
 300        strbuf_init(&io.input, 0);
 301        strbuf_attach(&io.input, result.ptr, result.size, result.size);
 302
 303        hunk_no = handle_path(sha1, (struct rerere_io *)&io);
 304        strbuf_release(&io.input);
 305        if (io.io.output)
 306                fclose(io.io.output);
 307        return hunk_no;
 308}
 309
 310static int find_conflict(struct string_list *conflict)
 311{
 312        int i;
 313        if (read_cache() < 0)
 314                return error("Could not read index");
 315        for (i = 0; i+1 < active_nr; i++) {
 316                struct cache_entry *e2 = active_cache[i];
 317                struct cache_entry *e3 = active_cache[i+1];
 318                if (ce_stage(e2) == 2 &&
 319                    ce_stage(e3) == 3 &&
 320                    ce_same_name(e2, e3) &&
 321                    S_ISREG(e2->ce_mode) &&
 322                    S_ISREG(e3->ce_mode)) {
 323                        string_list_insert((const char *)e2->name, conflict);
 324                        i++; /* skip over both #2 and #3 */
 325                }
 326        }
 327        return 0;
 328}
 329
 330static int merge(const char *name, const char *path)
 331{
 332        int ret;
 333        mmfile_t cur, base, other;
 334        mmbuffer_t result = {NULL, 0};
 335        xpparam_t xpp = {XDF_NEED_MINIMAL};
 336
 337        if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
 338                return 1;
 339
 340        if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
 341                        read_mmfile(&base, rerere_path(name, "preimage")) ||
 342                        read_mmfile(&other, rerere_path(name, "postimage")))
 343                return 1;
 344        ret = xdl_merge(&base, &cur, "", &other, "",
 345                        &xpp, XDL_MERGE_ZEALOUS, &result);
 346        if (!ret) {
 347                FILE *f = fopen(path, "w");
 348                if (!f)
 349                        return error("Could not open %s: %s", path,
 350                                     strerror(errno));
 351                if (fwrite(result.ptr, result.size, 1, f) != 1)
 352                        error("Could not write %s: %s", path, strerror(errno));
 353                if (fclose(f))
 354                        return error("Writing %s failed: %s", path,
 355                                     strerror(errno));
 356        }
 357
 358        free(cur.ptr);
 359        free(base.ptr);
 360        free(other.ptr);
 361        free(result.ptr);
 362
 363        return ret;
 364}
 365
 366static struct lock_file index_lock;
 367
 368static int update_paths(struct string_list *update)
 369{
 370        int i;
 371        int fd = hold_locked_index(&index_lock, 0);
 372        int status = 0;
 373
 374        if (fd < 0)
 375                return -1;
 376
 377        for (i = 0; i < update->nr; i++) {
 378                struct string_list_item *item = &update->items[i];
 379                if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
 380                        status = -1;
 381        }
 382
 383        if (!status && active_cache_changed) {
 384                if (write_cache(fd, active_cache, active_nr) ||
 385                    commit_locked_index(&index_lock))
 386                        die("Unable to write new index file");
 387        } else if (fd >= 0)
 388                rollback_lock_file(&index_lock);
 389        return status;
 390}
 391
 392static int do_plain_rerere(struct string_list *rr, int fd)
 393{
 394        struct string_list conflict = { NULL, 0, 0, 1 };
 395        struct string_list update = { NULL, 0, 0, 1 };
 396        int i;
 397
 398        find_conflict(&conflict);
 399
 400        /*
 401         * MERGE_RR records paths with conflicts immediately after merge
 402         * failed.  Some of the conflicted paths might have been hand resolved
 403         * in the working tree since then, but the initial run would catch all
 404         * and register their preimages.
 405         */
 406
 407        for (i = 0; i < conflict.nr; i++) {
 408                const char *path = conflict.items[i].string;
 409                if (!string_list_has_string(rr, path)) {
 410                        unsigned char sha1[20];
 411                        char *hex;
 412                        int ret;
 413                        ret = handle_file(path, sha1, NULL);
 414                        if (ret < 1)
 415                                continue;
 416                        hex = xstrdup(sha1_to_hex(sha1));
 417                        string_list_insert(path, rr)->util = hex;
 418                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 419                                continue;
 420                        handle_file(path, NULL, rerere_path(hex, "preimage"));
 421                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 422                }
 423        }
 424
 425        /*
 426         * Now some of the paths that had conflicts earlier might have been
 427         * hand resolved.  Others may be similar to a conflict already that
 428         * was resolved before.
 429         */
 430
 431        for (i = 0; i < rr->nr; i++) {
 432                int ret;
 433                const char *path = rr->items[i].string;
 434                const char *name = (const char *)rr->items[i].util;
 435
 436                if (has_rerere_resolution(name)) {
 437                        if (!merge(name, path)) {
 438                                if (rerere_autoupdate)
 439                                        string_list_insert(path, &update);
 440                                fprintf(stderr,
 441                                        "%s '%s' using previous resolution.\n",
 442                                        rerere_autoupdate
 443                                        ? "Staged" : "Resolved",
 444                                        path);
 445                                goto mark_resolved;
 446                        }
 447                }
 448
 449                /* Let's see if we have resolved it. */
 450                ret = handle_file(path, NULL, NULL);
 451                if (ret)
 452                        continue;
 453
 454                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 455                copy_file(rerere_path(name, "postimage"), path, 0666);
 456        mark_resolved:
 457                rr->items[i].util = NULL;
 458        }
 459
 460        if (update.nr)
 461                update_paths(&update);
 462
 463        return write_rr(rr, fd);
 464}
 465
 466static int git_rerere_config(const char *var, const char *value, void *cb)
 467{
 468        if (!strcmp(var, "rerere.enabled"))
 469                rerere_enabled = git_config_bool(var, value);
 470        else if (!strcmp(var, "rerere.autoupdate"))
 471                rerere_autoupdate = git_config_bool(var, value);
 472        else
 473                return git_default_config(var, value, cb);
 474        return 0;
 475}
 476
 477static int is_rerere_enabled(void)
 478{
 479        const char *rr_cache;
 480        int rr_cache_exists;
 481
 482        if (!rerere_enabled)
 483                return 0;
 484
 485        rr_cache = git_path("rr-cache");
 486        rr_cache_exists = is_directory(rr_cache);
 487        if (rerere_enabled < 0)
 488                return rr_cache_exists;
 489
 490        if (!rr_cache_exists &&
 491            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 492                die("Could not create directory %s", rr_cache);
 493        return 1;
 494}
 495
 496int setup_rerere(struct string_list *merge_rr, int flags)
 497{
 498        int fd;
 499
 500        git_config(git_rerere_config, NULL);
 501        if (!is_rerere_enabled())
 502                return -1;
 503
 504        if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
 505                rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
 506        merge_rr_path = git_pathdup("MERGE_RR");
 507        fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
 508                                       LOCK_DIE_ON_ERROR);
 509        read_rr(merge_rr);
 510        return fd;
 511}
 512
 513int rerere(int flags)
 514{
 515        struct string_list merge_rr = { NULL, 0, 0, 1 };
 516        int fd;
 517
 518        fd = setup_rerere(&merge_rr, flags);
 519        if (fd < 0)
 520                return 0;
 521        return do_plain_rerere(&merge_rr, fd);
 522}
 523
 524static int rerere_forget_one_path(const char *path, struct string_list *rr)
 525{
 526        const char *filename;
 527        char *hex;
 528        unsigned char sha1[20];
 529        int ret;
 530
 531        ret = handle_cache(path, sha1, NULL);
 532        if (ret < 1)
 533                return error("Could not parse conflict hunks in '%s'", path);
 534        hex = xstrdup(sha1_to_hex(sha1));
 535        filename = rerere_path(hex, "postimage");
 536        if (unlink(filename))
 537                return (errno == ENOENT
 538                        ? error("no remembered resolution for %s", path)
 539                        : error("cannot unlink %s: %s", filename, strerror(errno)));
 540
 541        handle_cache(path, sha1, rerere_path(hex, "preimage"));
 542        fprintf(stderr, "Updated preimage for '%s'\n", path);
 543
 544
 545        string_list_insert(path, rr)->util = hex;
 546        fprintf(stderr, "Forgot resolution for %s\n", path);
 547        return 0;
 548}
 549
 550int rerere_forget(const char **pathspec)
 551{
 552        int i, fd;
 553        struct string_list conflict = { NULL, 0, 0, 1 };
 554        struct string_list merge_rr = { NULL, 0, 0, 1 };
 555
 556        if (read_cache() < 0)
 557                return error("Could not read index");
 558
 559        fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
 560
 561        unmerge_cache(pathspec);
 562        find_conflict(&conflict);
 563        for (i = 0; i < conflict.nr; i++) {
 564                struct string_list_item *it = &conflict.items[i];
 565                if (!match_pathspec(pathspec, it->string, strlen(it->string),
 566                                    0, NULL))
 567                        continue;
 568                rerere_forget_one_path(it->string, &merge_rr);
 569        }
 570        return write_rr(&merge_rr, fd);
 571}