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