Andrew's git - gitweb.git/blob

   1#include "builtin.h"
   2#include "cache.h"
   3#include "path-list.h"
   4#include "xdiff/xdiff.h"
   5#include "xdiff-interface.h"
   6
   7#include <time.h>
   8
   9static const char git_rerere_usage[] =
  10"git-rerere [clear | status | diff | gc]";
  11
  12/* these values are days */
  13static int cutoff_noresolve = 15;
  14static int cutoff_resolve = 60;
  15
  16/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
  17static int rerere_enabled = -1;
  18
  19/* automatically update cleanly resolved paths to the index */
  20static int rerere_autoupdate;
  21
  22static char *merge_rr_path;
  23
  24static const char *rr_path(const char *name, const char *file)
  25{
  26        return git_path("rr-cache/%s/%s", name, file);
  27}
  28
  29static time_t rerere_created_at(const char *name)
  30{
  31        struct stat st;
  32        return stat(rr_path(name, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
  33}
  34
  35static int has_resolution(const char *name)
  36{
  37        struct stat st;
  38        return !stat(rr_path(name, "postimage"), &st);
  39}
  40
  41static void read_rr(struct path_list *rr)
  42{
  43        unsigned char sha1[20];
  44        char buf[PATH_MAX];
  45        FILE *in = fopen(merge_rr_path, "r");
  46        if (!in)
  47                return;
  48        while (fread(buf, 40, 1, in) == 1) {
  49                int i;
  50                char *name;
  51                if (get_sha1_hex(buf, sha1))
  52                        die("corrupt MERGE_RR");
  53                buf[40] = '\0';
  54                name = xstrdup(buf);
  55                if (fgetc(in) != '\t')
  56                        die("corrupt MERGE_RR");
  57                for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
  58                        ; /* do nothing */
  59                if (i == sizeof(buf))
  60                        die("filename too long");
  61                path_list_insert(buf, rr)->util = name;
  62        }
  63        fclose(in);
  64}
  65
  66static struct lock_file write_lock;
  67
  68static int write_rr(struct path_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].path;
  77                length = strlen(path) + 1;
  78                if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
  79                    write_in_full(out_fd, "\t", 1) != 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
  88static int handle_file(const char *path,
  89         unsigned char *sha1, const char *output)
  90{
  91        SHA_CTX ctx;
  92        char buf[1024];
  93        int hunk = 0, hunk_no = 0;
  94        struct strbuf one, two;
  95        FILE *f = fopen(path, "r");
  96        FILE *out = NULL;
  97
  98        if (!f)
  99                return error("Could not open %s", path);
 100
 101        if (output) {
 102                out = fopen(output, "w");
 103                if (!out) {
 104                        fclose(f);
 105                        return error("Could not write %s", output);
 106                }
 107        }
 108
 109        if (sha1)
 110                SHA1_Init(&ctx);
 111
 112        strbuf_init(&one, 0);
 113        strbuf_init(&two,  0);
 114        while (fgets(buf, sizeof(buf), f)) {
 115                if (!prefixcmp(buf, "<<<<<<< ")) {
 116                        if (hunk)
 117                                goto bad;
 118                        hunk = 1;
 119                } else if (!prefixcmp(buf, "=======") && isspace(buf[7])) {
 120                        if (hunk != 1)
 121                                goto bad;
 122                        hunk = 2;
 123                } else if (!prefixcmp(buf, ">>>>>>> ")) {
 124                        if (hunk != 2)
 125                                goto bad;
 126                        if (strbuf_cmp(&one, &two) > 0)
 127                                strbuf_swap(&one, &two);
 128                        hunk_no++;
 129                        hunk = 0;
 130                        if (out) {
 131                                fputs("<<<<<<<\n", out);
 132                                fwrite(one.buf, one.len, 1, out);
 133                                fputs("=======\n", out);
 134                                fwrite(two.buf, two.len, 1, out);
 135                                fputs(">>>>>>>\n", out);
 136                        }
 137                        if (sha1) {
 138                                SHA1_Update(&ctx, one.buf ? one.buf : "",
 139                                            one.len + 1);
 140                                SHA1_Update(&ctx, two.buf ? two.buf : "",
 141                                            two.len + 1);
 142                        }
 143                        strbuf_reset(&one);
 144                        strbuf_reset(&two);
 145                } else if (hunk == 1)
 146                        strbuf_addstr(&one, buf);
 147                else if (hunk == 2)
 148                        strbuf_addstr(&two, buf);
 149                else if (out)
 150                        fputs(buf, out);
 151                continue;
 152        bad:
 153                hunk = 99; /* force error exit */
 154                break;
 155        }
 156        strbuf_release(&one);
 157        strbuf_release(&two);
 158
 159        fclose(f);
 160        if (out)
 161                fclose(out);
 162        if (sha1)
 163                SHA1_Final(sha1, &ctx);
 164        if (hunk) {
 165                if (output)
 166                        unlink(output);
 167                return error("Could not parse conflict hunks in %s", path);
 168        }
 169        return hunk_no;
 170}
 171
 172static int find_conflict(struct path_list *conflict)
 173{
 174        int i;
 175        if (read_cache() < 0)
 176                return error("Could not read index");
 177        for (i = 0; i+1 < active_nr; i++) {
 178                struct cache_entry *e2 = active_cache[i];
 179                struct cache_entry *e3 = active_cache[i+1];
 180                if (ce_stage(e2) == 2 &&
 181                    ce_stage(e3) == 3 &&
 182                    ce_same_name(e2, e3) &&
 183                    S_ISREG(e2->ce_mode) &&
 184                    S_ISREG(e3->ce_mode)) {
 185                        path_list_insert((const char *)e2->name, conflict);
 186                        i++; /* skip over both #2 and #3 */
 187                }
 188        }
 189        return 0;
 190}
 191
 192static int merge(const char *name, const char *path)
 193{
 194        int ret;
 195        mmfile_t cur, base, other;
 196        mmbuffer_t result = {NULL, 0};
 197        xpparam_t xpp = {XDF_NEED_MINIMAL};
 198
 199        if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 200                return 1;
 201
 202        if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 203                        read_mmfile(&base, rr_path(name, "preimage")) ||
 204                        read_mmfile(&other, rr_path(name, "postimage")))
 205                return 1;
 206        ret = xdl_merge(&base, &cur, "", &other, "",
 207                        &xpp, XDL_MERGE_ZEALOUS, &result);
 208        if (!ret) {
 209                FILE *f = fopen(path, "w");
 210                if (!f)
 211                        return error("Could not write to %s", path);
 212                fwrite(result.ptr, result.size, 1, f);
 213                fclose(f);
 214        }
 215
 216        free(cur.ptr);
 217        free(base.ptr);
 218        free(other.ptr);
 219        free(result.ptr);
 220
 221        return ret;
 222}
 223
 224static void unlink_rr_item(const char *name)
 225{
 226        unlink(rr_path(name, "thisimage"));
 227        unlink(rr_path(name, "preimage"));
 228        unlink(rr_path(name, "postimage"));
 229        rmdir(git_path("rr-cache/%s", name));
 230}
 231
 232static void garbage_collect(struct path_list *rr)
 233{
 234        struct path_list to_remove = { NULL, 0, 0, 1 };
 235        DIR *dir;
 236        struct dirent *e;
 237        int i, cutoff;
 238        time_t now = time(NULL), then;
 239
 240        dir = opendir(git_path("rr-cache"));
 241        while ((e = readdir(dir))) {
 242                const char *name = e->d_name;
 243                if (name[0] == '.' &&
 244                    (name[1] == '\0' || (name[1] == '.' && name[2] == '\0')))
 245                        continue;
 246                then = rerere_created_at(name);
 247                if (!then)
 248                        continue;
 249                cutoff = (has_resolution(name)
 250                          ? cutoff_resolve : cutoff_noresolve);
 251                if (then < now - cutoff * 86400)
 252                        path_list_append(name, &to_remove);
 253        }
 254        for (i = 0; i < to_remove.nr; i++)
 255                unlink_rr_item(to_remove.items[i].path);
 256        path_list_clear(&to_remove, 0);
 257}
 258
 259static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
 260{
 261        int i;
 262        for (i = 0; i < nbuf; i++)
 263                if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
 264                        return -1;
 265        return 0;
 266}
 267
 268static int diff_two(const char *file1, const char *label1,
 269                const char *file2, const char *label2)
 270{
 271        xpparam_t xpp;
 272        xdemitconf_t xecfg;
 273        xdemitcb_t ecb;
 274        mmfile_t minus, plus;
 275
 276        if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
 277                return 1;
 278
 279        printf("--- a/%s\n+++ b/%s\n", label1, label2);
 280        fflush(stdout);
 281        xpp.flags = XDF_NEED_MINIMAL;
 282        memset(&xecfg, 0, sizeof(xecfg));
 283        xecfg.ctxlen = 3;
 284        ecb.outf = outf;
 285        xdi_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 286
 287        free(minus.ptr);
 288        free(plus.ptr);
 289        return 0;
 290}
 291
 292static struct lock_file index_lock;
 293
 294static int update_paths(struct path_list *update)
 295{
 296        int i;
 297        int fd = hold_locked_index(&index_lock, 0);
 298        int status = 0;
 299
 300        if (fd < 0)
 301                return -1;
 302
 303        for (i = 0; i < update->nr; i++) {
 304                struct path_list_item *item = &update->items[i];
 305                if (add_file_to_cache(item->path, ADD_CACHE_IGNORE_ERRORS))
 306                        status = -1;
 307        }
 308
 309        if (!status && active_cache_changed) {
 310                if (write_cache(fd, active_cache, active_nr) ||
 311                    commit_locked_index(&index_lock))
 312                        die("Unable to write new index file");
 313        } else if (fd >= 0)
 314                rollback_lock_file(&index_lock);
 315        return status;
 316}
 317
 318static int do_plain_rerere(struct path_list *rr, int fd)
 319{
 320        struct path_list conflict = { NULL, 0, 0, 1 };
 321        struct path_list update = { NULL, 0, 0, 1 };
 322        int i;
 323
 324        find_conflict(&conflict);
 325
 326        /*
 327         * MERGE_RR records paths with conflicts immediately after merge
 328         * failed.  Some of the conflicted paths might have been hand resolved
 329         * in the working tree since then, but the initial run would catch all
 330         * and register their preimages.
 331         */
 332
 333        for (i = 0; i < conflict.nr; i++) {
 334                const char *path = conflict.items[i].path;
 335                if (!path_list_has_path(rr, path)) {
 336                        unsigned char sha1[20];
 337                        char *hex;
 338                        int ret;
 339                        ret = handle_file(path, sha1, NULL);
 340                        if (ret < 1)
 341                                continue;
 342                        hex = xstrdup(sha1_to_hex(sha1));
 343                        path_list_insert(path, rr)->util = hex;
 344                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 345                                continue;;
 346                        handle_file(path, NULL, rr_path(hex, "preimage"));
 347                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 348                }
 349        }
 350
 351        /*
 352         * Now some of the paths that had conflicts earlier might have been
 353         * hand resolved.  Others may be similar to a conflict already that
 354         * was resolved before.
 355         */
 356
 357        for (i = 0; i < rr->nr; i++) {
 358                int ret;
 359                const char *path = rr->items[i].path;
 360                const char *name = (const char *)rr->items[i].util;
 361
 362                if (has_resolution(name)) {
 363                        if (!merge(name, path)) {
 364                                fprintf(stderr, "Resolved '%s' using "
 365                                                "previous resolution.\n", path);
 366                                if (rerere_autoupdate)
 367                                        path_list_insert(path, &update);
 368                                goto mark_resolved;
 369                        }
 370                }
 371
 372                /* Let's see if we have resolved it. */
 373                ret = handle_file(path, NULL, NULL);
 374                if (ret)
 375                        continue;
 376
 377                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 378                copy_file(rr_path(name, "postimage"), path, 0666);
 379        mark_resolved:
 380                rr->items[i].util = NULL;
 381        }
 382
 383        if (update.nr)
 384                update_paths(&update);
 385
 386        return write_rr(rr, fd);
 387}
 388
 389static int git_rerere_config(const char *var, const char *value, void *cb)
 390{
 391        if (!strcmp(var, "gc.rerereresolved"))
 392                cutoff_resolve = git_config_int(var, value);
 393        else if (!strcmp(var, "gc.rerereunresolved"))
 394                cutoff_noresolve = git_config_int(var, value);
 395        else if (!strcmp(var, "rerere.enabled"))
 396                rerere_enabled = git_config_bool(var, value);
 397        else if (!strcmp(var, "rerere.autoupdate"))
 398                rerere_autoupdate = git_config_bool(var, value);
 399        else
 400                return git_default_config(var, value, cb);
 401        return 0;
 402}
 403
 404static int is_rerere_enabled(void)
 405{
 406        struct stat st;
 407        const char *rr_cache;
 408        int rr_cache_exists;
 409
 410        if (!rerere_enabled)
 411                return 0;
 412
 413        rr_cache = git_path("rr-cache");
 414        rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
 415        if (rerere_enabled < 0)
 416                return rr_cache_exists;
 417
 418        if (!rr_cache_exists &&
 419            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 420                die("Could not create directory %s", rr_cache);
 421        return 1;
 422}
 423
 424static int setup_rerere(struct path_list *merge_rr)
 425{
 426        int fd;
 427
 428        git_config(git_rerere_config, NULL);
 429        if (!is_rerere_enabled())
 430                return -1;
 431
 432        merge_rr_path = xstrdup(git_path("MERGE_RR"));
 433        fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
 434        read_rr(merge_rr);
 435        return fd;
 436}
 437
 438int rerere(void)
 439{
 440        struct path_list merge_rr = { NULL, 0, 0, 1 };
 441        int fd;
 442
 443        fd = setup_rerere(&merge_rr);
 444        if (fd < 0)
 445                return 0;
 446        return do_plain_rerere(&merge_rr, fd);
 447}
 448
 449int cmd_rerere(int argc, const char **argv, const char *prefix)
 450{
 451        struct path_list merge_rr = { NULL, 0, 0, 1 };
 452        int i, fd;
 453
 454        fd = setup_rerere(&merge_rr);
 455        if (fd < 0)
 456                return 0;
 457
 458        if (argc < 2)
 459                return do_plain_rerere(&merge_rr, fd);
 460        else if (!strcmp(argv[1], "clear")) {
 461                for (i = 0; i < merge_rr.nr; i++) {
 462                        const char *name = (const char *)merge_rr.items[i].util;
 463                        if (!has_resolution(name))
 464                                unlink_rr_item(name);
 465                }
 466                unlink(merge_rr_path);
 467        } else if (!strcmp(argv[1], "gc"))
 468                garbage_collect(&merge_rr);
 469        else if (!strcmp(argv[1], "status"))
 470                for (i = 0; i < merge_rr.nr; i++)
 471                        printf("%s\n", merge_rr.items[i].path);
 472        else if (!strcmp(argv[1], "diff"))
 473                for (i = 0; i < merge_rr.nr; i++) {
 474                        const char *path = merge_rr.items[i].path;
 475                        const char *name = (const char *)merge_rr.items[i].util;
 476                        diff_two(rr_path(name, "preimage"), path, path, path);
 477                }
 478        else
 479                usage(git_rerere_usage);
 480
 481        path_list_clear(&merge_rr, 1);
 482        return 0;
 483}