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
  19static char *merge_rr_path;
  20
  21static const char *rr_path(const char *name, const char *file)
  22{
  23        return git_path("rr-cache/%s/%s", name, file);
  24}
  25
  26static void read_rr(struct path_list *rr)
  27{
  28        unsigned char sha1[20];
  29        char buf[PATH_MAX];
  30        FILE *in = fopen(merge_rr_path, "r");
  31        if (!in)
  32                return;
  33        while (fread(buf, 40, 1, in) == 1) {
  34                int i;
  35                char *name;
  36                if (get_sha1_hex(buf, sha1))
  37                        die("corrupt MERGE_RR");
  38                buf[40] = '\0';
  39                name = xstrdup(buf);
  40                if (fgetc(in) != '\t')
  41                        die("corrupt MERGE_RR");
  42                for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
  43                        ; /* do nothing */
  44                if (i == sizeof(buf))
  45                        die("filename too long");
  46                path_list_insert(buf, rr)->util = xstrdup(name);
  47        }
  48        fclose(in);
  49}
  50
  51static struct lock_file write_lock;
  52
  53static int write_rr(struct path_list *rr, int out_fd)
  54{
  55        int i;
  56        for (i = 0; i < rr->nr; i++) {
  57                const char *path = rr->items[i].path;
  58                int length = strlen(path) + 1;
  59                if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
  60                    write_in_full(out_fd, "\t", 1) != 1 ||
  61                    write_in_full(out_fd, path, length) != length)
  62                        die("unable to write rerere record");
  63        }
  64        if (commit_lock_file(&write_lock) != 0)
  65                die("unable to write rerere record");
  66        return 0;
  67}
  68
  69static int handle_file(const char *path,
  70         unsigned char *sha1, const char *output)
  71{
  72        SHA_CTX ctx;
  73        char buf[1024];
  74        int hunk = 0, hunk_no = 0;
  75        struct strbuf one, two;
  76        FILE *f = fopen(path, "r");
  77        FILE *out = NULL;
  78
  79        if (!f)
  80                return error("Could not open %s", path);
  81
  82        if (output) {
  83                out = fopen(output, "w");
  84                if (!out) {
  85                        fclose(f);
  86                        return error("Could not write %s", output);
  87                }
  88        }
  89
  90        if (sha1)
  91                SHA1_Init(&ctx);
  92
  93        strbuf_init(&one, 0);
  94        strbuf_init(&two,  0);
  95        while (fgets(buf, sizeof(buf), f)) {
  96                if (!prefixcmp(buf, "<<<<<<< "))
  97                        hunk = 1;
  98                else if (!prefixcmp(buf, "======="))
  99                        hunk = 2;
 100                else if (!prefixcmp(buf, ">>>>>>> ")) {
 101                        int cmp = strbuf_cmp(&one, &two);
 102
 103                        hunk_no++;
 104                        hunk = 0;
 105                        if (cmp > 0) {
 106                                strbuf_swap(&one, &two);
 107                        }
 108                        if (out) {
 109                                fputs("<<<<<<<\n", out);
 110                                fwrite(one.buf, one.len, 1, out);
 111                                fputs("=======\n", out);
 112                                fwrite(two.buf, two.len, 1, out);
 113                                fputs(">>>>>>>\n", out);
 114                        }
 115                        if (sha1) {
 116                                SHA1_Update(&ctx, one.buf ? one.buf : "",
 117                                            one.len + 1);
 118                                SHA1_Update(&ctx, two.buf ? two.buf : "",
 119                                            two.len + 1);
 120                        }
 121                        strbuf_reset(&one);
 122                        strbuf_reset(&two);
 123                } else if (hunk == 1)
 124                        strbuf_addstr(&one, buf);
 125                else if (hunk == 2)
 126                        strbuf_addstr(&two, buf);
 127                else if (out)
 128                        fputs(buf, out);
 129        }
 130        strbuf_release(&one);
 131        strbuf_release(&two);
 132
 133        fclose(f);
 134        if (out)
 135                fclose(out);
 136        if (sha1)
 137                SHA1_Final(sha1, &ctx);
 138        return hunk_no;
 139}
 140
 141static int find_conflict(struct path_list *conflict)
 142{
 143        int i;
 144        if (read_cache() < 0)
 145                return error("Could not read index");
 146        for (i = 0; i+1 < active_nr; i++) {
 147                struct cache_entry *e2 = active_cache[i];
 148                struct cache_entry *e3 = active_cache[i+1];
 149                if (ce_stage(e2) == 2 &&
 150                    ce_stage(e3) == 3 &&
 151                    ce_same_name(e2, e3) &&
 152                    S_ISREG(e2->ce_mode) &&
 153                    S_ISREG(e3->ce_mode)) {
 154                        path_list_insert((const char *)e2->name, conflict);
 155                        i++; /* skip over both #2 and #3 */
 156                }
 157        }
 158        return 0;
 159}
 160
 161static int merge(const char *name, const char *path)
 162{
 163        int ret;
 164        mmfile_t cur, base, other;
 165        mmbuffer_t result = {NULL, 0};
 166        xpparam_t xpp = {XDF_NEED_MINIMAL};
 167
 168        if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 169                return 1;
 170
 171        if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 172                        read_mmfile(&base, rr_path(name, "preimage")) ||
 173                        read_mmfile(&other, rr_path(name, "postimage")))
 174                return 1;
 175        ret = xdl_merge(&base, &cur, "", &other, "",
 176                        &xpp, XDL_MERGE_ZEALOUS, &result);
 177        if (!ret) {
 178                FILE *f = fopen(path, "w");
 179                if (!f)
 180                        return error("Could not write to %s", path);
 181                fwrite(result.ptr, result.size, 1, f);
 182                fclose(f);
 183        }
 184
 185        free(cur.ptr);
 186        free(base.ptr);
 187        free(other.ptr);
 188        free(result.ptr);
 189
 190        return ret;
 191}
 192
 193static void unlink_rr_item(const char *name)
 194{
 195        unlink(rr_path(name, "thisimage"));
 196        unlink(rr_path(name, "preimage"));
 197        unlink(rr_path(name, "postimage"));
 198        rmdir(git_path("rr-cache/%s", name));
 199}
 200
 201static void garbage_collect(struct path_list *rr)
 202{
 203        struct path_list to_remove = { NULL, 0, 0, 1 };
 204        char buf[1024];
 205        DIR *dir;
 206        struct dirent *e;
 207        int len, i, cutoff;
 208        time_t now = time(NULL), then;
 209
 210        strlcpy(buf, git_path("rr-cache"), sizeof(buf));
 211        len = strlen(buf);
 212        dir = opendir(buf);
 213        strcpy(buf + len++, "/");
 214        while ((e = readdir(dir))) {
 215                const char *name = e->d_name;
 216                struct stat st;
 217                if (name[0] == '.' && (name[1] == '\0' ||
 218                                        (name[1] == '.' && name[2] == '\0')))
 219                        continue;
 220                i = snprintf(buf + len, sizeof(buf) - len, "%s", name);
 221                strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i);
 222                if (stat(buf, &st))
 223                        continue;
 224                then = st.st_mtime;
 225                strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i);
 226                cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve;
 227                if (then < now - cutoff * 86400) {
 228                        buf[len + i] = '\0';
 229                        path_list_insert(xstrdup(name), &to_remove);
 230                }
 231        }
 232        for (i = 0; i < to_remove.nr; i++)
 233                unlink_rr_item(to_remove.items[i].path);
 234        path_list_clear(&to_remove, 0);
 235}
 236
 237static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
 238{
 239        int i;
 240        for (i = 0; i < nbuf; i++)
 241                if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
 242                        return -1;
 243        return 0;
 244}
 245
 246static int diff_two(const char *file1, const char *label1,
 247                const char *file2, const char *label2)
 248{
 249        xpparam_t xpp;
 250        xdemitconf_t xecfg;
 251        xdemitcb_t ecb;
 252        mmfile_t minus, plus;
 253
 254        if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
 255                return 1;
 256
 257        printf("--- a/%s\n+++ b/%s\n", label1, label2);
 258        fflush(stdout);
 259        xpp.flags = XDF_NEED_MINIMAL;
 260        memset(&xecfg, 0, sizeof(xecfg));
 261        xecfg.ctxlen = 3;
 262        ecb.outf = outf;
 263        xdi_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 264
 265        free(minus.ptr);
 266        free(plus.ptr);
 267        return 0;
 268}
 269
 270static int copy_file(const char *src, const char *dest)
 271{
 272        FILE *in, *out;
 273        char buffer[32768];
 274        int count;
 275
 276        if (!(in = fopen(src, "r")))
 277                return error("Could not open %s", src);
 278        if (!(out = fopen(dest, "w")))
 279                return error("Could not open %s", dest);
 280        while ((count = fread(buffer, 1, sizeof(buffer), in)))
 281                fwrite(buffer, 1, count, out);
 282        fclose(in);
 283        fclose(out);
 284        return 0;
 285}
 286
 287static int do_plain_rerere(struct path_list *rr, int fd)
 288{
 289        struct path_list conflict = { NULL, 0, 0, 1 };
 290        int i;
 291
 292        find_conflict(&conflict);
 293
 294        /*
 295         * MERGE_RR records paths with conflicts immediately after merge
 296         * failed.  Some of the conflicted paths might have been hand resolved
 297         * in the working tree since then, but the initial run would catch all
 298         * and register their preimages.
 299         */
 300
 301        for (i = 0; i < conflict.nr; i++) {
 302                const char *path = conflict.items[i].path;
 303                if (!path_list_has_path(rr, path)) {
 304                        unsigned char sha1[20];
 305                        char *hex;
 306                        int ret;
 307                        ret = handle_file(path, sha1, NULL);
 308                        if (ret < 1)
 309                                continue;
 310                        hex = xstrdup(sha1_to_hex(sha1));
 311                        path_list_insert(path, rr)->util = hex;
 312                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 313                                continue;;
 314                        handle_file(path, NULL, rr_path(hex, "preimage"));
 315                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 316                }
 317        }
 318
 319        /*
 320         * Now some of the paths that had conflicts earlier might have been
 321         * hand resolved.  Others may be similar to a conflict already that
 322         * was resolved before.
 323         */
 324
 325        for (i = 0; i < rr->nr; i++) {
 326                struct stat st;
 327                int ret;
 328                const char *path = rr->items[i].path;
 329                const char *name = (const char *)rr->items[i].util;
 330
 331                if (!stat(rr_path(name, "preimage"), &st) &&
 332                                !stat(rr_path(name, "postimage"), &st)) {
 333                        if (!merge(name, path)) {
 334                                fprintf(stderr, "Resolved '%s' using "
 335                                                "previous resolution.\n", path);
 336                                goto tail_optimization;
 337                        }
 338                }
 339
 340                /* Let's see if we have resolved it. */
 341                ret = handle_file(path, NULL, NULL);
 342                if (ret)
 343                        continue;
 344
 345                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 346                copy_file(path, rr_path(name, "postimage"));
 347tail_optimization:
 348                if (i < rr->nr - 1)
 349                        memmove(rr->items + i,
 350                                rr->items + i + 1,
 351                                sizeof(rr->items[0]) * (rr->nr - i - 1));
 352                rr->nr--;
 353                i--;
 354        }
 355
 356        return write_rr(rr, fd);
 357}
 358
 359static int git_rerere_config(const char *var, const char *value)
 360{
 361        if (!strcmp(var, "gc.rerereresolved"))
 362                cutoff_resolve = git_config_int(var, value);
 363        else if (!strcmp(var, "gc.rerereunresolved"))
 364                cutoff_noresolve = git_config_int(var, value);
 365        else if (!strcmp(var, "rerere.enabled"))
 366                rerere_enabled = git_config_bool(var, value);
 367        else
 368                return git_default_config(var, value);
 369        return 0;
 370}
 371
 372static int is_rerere_enabled(void)
 373{
 374        struct stat st;
 375        const char *rr_cache;
 376        int rr_cache_exists;
 377
 378        if (!rerere_enabled)
 379                return 0;
 380
 381        rr_cache = git_path("rr-cache");
 382        rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
 383        if (rerere_enabled < 0)
 384                return rr_cache_exists;
 385
 386        if (!rr_cache_exists &&
 387            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 388                die("Could not create directory %s", rr_cache);
 389        return 1;
 390}
 391
 392static int setup_rerere(struct path_list *merge_rr)
 393{
 394        int fd;
 395
 396        git_config(git_rerere_config);
 397        if (!is_rerere_enabled())
 398                return -1;
 399
 400        merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR"));
 401        fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
 402        read_rr(merge_rr);
 403        return fd;
 404}
 405
 406int rerere(void)
 407{
 408        struct path_list merge_rr = { NULL, 0, 0, 1 };
 409        int fd;
 410
 411        fd = setup_rerere(&merge_rr);
 412        if (fd < 0)
 413                return 0;
 414        return do_plain_rerere(&merge_rr, fd);
 415}
 416
 417int cmd_rerere(int argc, const char **argv, const char *prefix)
 418{
 419        struct path_list merge_rr = { NULL, 0, 0, 1 };
 420        int i, fd;
 421
 422        fd = setup_rerere(&merge_rr);
 423        if (fd < 0)
 424                return 0;
 425
 426        if (argc < 2)
 427                return do_plain_rerere(&merge_rr, fd);
 428        else if (!strcmp(argv[1], "clear")) {
 429                for (i = 0; i < merge_rr.nr; i++) {
 430                        struct stat st;
 431                        const char *name = (const char *)merge_rr.items[i].util;
 432                        if (!stat(git_path("rr-cache/%s", name), &st) &&
 433                                        S_ISDIR(st.st_mode) &&
 434                                        stat(rr_path(name, "postimage"), &st))
 435                                unlink_rr_item(name);
 436                }
 437                unlink(merge_rr_path);
 438        } else if (!strcmp(argv[1], "gc"))
 439                garbage_collect(&merge_rr);
 440        else if (!strcmp(argv[1], "status"))
 441                for (i = 0; i < merge_rr.nr; i++)
 442                        printf("%s\n", merge_rr.items[i].path);
 443        else if (!strcmp(argv[1], "diff"))
 444                for (i = 0; i < merge_rr.nr; i++) {
 445                        const char *path = merge_rr.items[i].path;
 446                        const char *name = (const char *)merge_rr.items[i].util;
 447                        diff_two(rr_path(name, "preimage"), path, path, path);
 448                }
 449        else
 450                usage(git_rerere_usage);
 451
 452        path_list_clear(&merge_rr, 1);
 453        return 0;
 454}