Andrew's git - gitweb.git/blob

   1#include "builtin.h"
   2#include "cache.h"
   3#include "path-list.h"
   4#include "strbuf.h"
   5#include "xdiff/xdiff.h"
   6#include "xdiff-interface.h"
   7
   8#include <time.h>
   9
  10static const char git_rerere_usage[] =
  11"git-rerere [clear | status | diff | gc]";
  12
  13/* these values are days */
  14static int cutoff_noresolve = 15;
  15static int cutoff_resolve = 60;
  16
  17/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
  18static int rerere_enabled = -1;
  19
  20static char *merge_rr_path;
  21
  22static const char *rr_path(const char *name, const char *file)
  23{
  24        return git_path("rr-cache/%s/%s", name, file);
  25}
  26
  27static void read_rr(struct path_list *rr)
  28{
  29        unsigned char sha1[20];
  30        char buf[PATH_MAX];
  31        FILE *in = fopen(merge_rr_path, "r");
  32        if (!in)
  33                return;
  34        while (fread(buf, 40, 1, in) == 1) {
  35                int i;
  36                char *name;
  37                if (get_sha1_hex(buf, sha1))
  38                        die("corrupt MERGE_RR");
  39                buf[40] = '\0';
  40                name = xstrdup(buf);
  41                if (fgetc(in) != '\t')
  42                        die("corrupt MERGE_RR");
  43                for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
  44                        ; /* do nothing */
  45                if (i == sizeof(buf))
  46                        die("filename too long");
  47                path_list_insert(buf, rr)->util = xstrdup(name);
  48        }
  49        fclose(in);
  50}
  51
  52static struct lock_file write_lock;
  53
  54static int write_rr(struct path_list *rr, int out_fd)
  55{
  56        int i;
  57        for (i = 0; i < rr->nr; i++) {
  58                const char *path = rr->items[i].path;
  59                int length = strlen(path) + 1;
  60                if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
  61                    write_in_full(out_fd, "\t", 1) != 1 ||
  62                    write_in_full(out_fd, path, length) != length)
  63                        die("unable to write rerere record");
  64        }
  65        if (close(out_fd) != 0)
  66                die("unable to write rerere record");
  67        return commit_lock_file(&write_lock);
  68}
  69
  70static int handle_file(const char *path,
  71         unsigned char *sha1, const char *output)
  72{
  73        SHA_CTX ctx;
  74        char buf[1024];
  75        int hunk = 0, hunk_no = 0;
  76        struct strbuf minus, plus;
  77        struct strbuf *one = &minus, *two = &plus;
  78        FILE *f = fopen(path, "r");
  79        FILE *out;
  80
  81        strbuf_init(&minus);
  82        strbuf_init(&plus);
  83
  84        if (!f)
  85                return error("Could not open %s", path);
  86
  87        if (output) {
  88                out = fopen(output, "w");
  89                if (!out) {
  90                        fclose(f);
  91                        return error("Could not write %s", output);
  92                }
  93        } else
  94                out = NULL;
  95
  96        if (sha1)
  97                SHA1_Init(&ctx);
  98
  99        while (fgets(buf, sizeof(buf), f)) {
 100                if (!prefixcmp(buf, "<<<<<<< "))
 101                        hunk = 1;
 102                else if (!prefixcmp(buf, "======="))
 103                        hunk = 2;
 104                else if (!prefixcmp(buf, ">>>>>>> ")) {
 105                        int one_is_longer = (one->len > two->len);
 106                        int common_len = one_is_longer ? two->len : one->len;
 107                        int cmp = memcmp(one->buf, two->buf, common_len);
 108
 109                        hunk_no++;
 110                        hunk = 0;
 111                        if ((cmp > 0) || ((cmp == 0) && one_is_longer)) {
 112                                struct strbuf *swap = one;
 113                                one = two;
 114                                two = swap;
 115                        }
 116                        if (out) {
 117                                fputs("<<<<<<<\n", out);
 118                                fwrite(one->buf, one->len, 1, out);
 119                                fputs("=======\n", out);
 120                                fwrite(two->buf, two->len, 1, out);
 121                                fputs(">>>>>>>\n", out);
 122                        }
 123                        if (sha1) {
 124                                SHA1_Update(&ctx, one->buf, one->len);
 125                                SHA1_Update(&ctx, "\0", 1);
 126                                SHA1_Update(&ctx, two->buf, two->len);
 127                                SHA1_Update(&ctx, "\0", 1);
 128                        }
 129                        strbuf_release(one);
 130                        strbuf_release(two);
 131                } else if (hunk == 1)
 132                        strbuf_addstr(one, buf);
 133                else if (hunk == 2)
 134                        strbuf_addstr(two, buf);
 135                else if (out)
 136                        fputs(buf, out);
 137        }
 138
 139        fclose(f);
 140        if (out)
 141                fclose(out);
 142        if (sha1)
 143                SHA1_Final(sha1, &ctx);
 144        return hunk_no;
 145}
 146
 147static int find_conflict(struct path_list *conflict)
 148{
 149        int i;
 150        if (read_cache() < 0)
 151                return error("Could not read index");
 152        for (i = 0; i+1 < active_nr; i++) {
 153                struct cache_entry *e2 = active_cache[i];
 154                struct cache_entry *e3 = active_cache[i+1];
 155                if (ce_stage(e2) == 2 &&
 156                    ce_stage(e3) == 3 &&
 157                    ce_same_name(e2, e3) &&
 158                    S_ISREG(ntohl(e2->ce_mode)) &&
 159                    S_ISREG(ntohl(e3->ce_mode))) {
 160                        path_list_insert((const char *)e2->name, conflict);
 161                        i++; /* skip over both #2 and #3 */
 162                }
 163        }
 164        return 0;
 165}
 166
 167static int merge(const char *name, const char *path)
 168{
 169        int ret;
 170        mmfile_t cur, base, other;
 171        mmbuffer_t result = {NULL, 0};
 172        xpparam_t xpp = {XDF_NEED_MINIMAL};
 173
 174        if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 175                return 1;
 176
 177        if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 178                        read_mmfile(&base, rr_path(name, "preimage")) ||
 179                        read_mmfile(&other, rr_path(name, "postimage")))
 180                return 1;
 181        ret = xdl_merge(&base, &cur, "", &other, "",
 182                        &xpp, XDL_MERGE_ZEALOUS, &result);
 183        if (!ret) {
 184                FILE *f = fopen(path, "w");
 185                if (!f)
 186                        return error("Could not write to %s", path);
 187                fwrite(result.ptr, result.size, 1, f);
 188                fclose(f);
 189        }
 190
 191        free(cur.ptr);
 192        free(base.ptr);
 193        free(other.ptr);
 194        free(result.ptr);
 195
 196        return ret;
 197}
 198
 199static void unlink_rr_item(const char *name)
 200{
 201        unlink(rr_path(name, "thisimage"));
 202        unlink(rr_path(name, "preimage"));
 203        unlink(rr_path(name, "postimage"));
 204        rmdir(git_path("rr-cache/%s", name));
 205}
 206
 207static void garbage_collect(struct path_list *rr)
 208{
 209        struct path_list to_remove = { NULL, 0, 0, 1 };
 210        char buf[1024];
 211        DIR *dir;
 212        struct dirent *e;
 213        int len, i, cutoff;
 214        time_t now = time(NULL), then;
 215
 216        strlcpy(buf, git_path("rr-cache"), sizeof(buf));
 217        len = strlen(buf);
 218        dir = opendir(buf);
 219        strcpy(buf + len++, "/");
 220        while ((e = readdir(dir))) {
 221                const char *name = e->d_name;
 222                struct stat st;
 223                if (name[0] == '.' && (name[1] == '\0' ||
 224                                        (name[1] == '.' && name[2] == '\0')))
 225                        continue;
 226                i = snprintf(buf + len, sizeof(buf) - len, "%s", name);
 227                strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i);
 228                if (stat(buf, &st))
 229                        continue;
 230                then = st.st_mtime;
 231                strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i);
 232                cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve;
 233                if (then < now - cutoff * 86400) {
 234                        buf[len + i] = '\0';
 235                        path_list_insert(xstrdup(name), &to_remove);
 236                }
 237        }
 238        for (i = 0; i < to_remove.nr; i++)
 239                unlink_rr_item(to_remove.items[i].path);
 240        path_list_clear(&to_remove, 0);
 241}
 242
 243static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
 244{
 245        int i;
 246        for (i = 0; i < nbuf; i++)
 247                if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
 248                        return -1;
 249        return 0;
 250}
 251
 252static int diff_two(const char *file1, const char *label1,
 253                const char *file2, const char *label2)
 254{
 255        xpparam_t xpp;
 256        xdemitconf_t xecfg;
 257        xdemitcb_t ecb;
 258        mmfile_t minus, plus;
 259
 260        if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
 261                return 1;
 262
 263        printf("--- a/%s\n+++ b/%s\n", label1, label2);
 264        fflush(stdout);
 265        xpp.flags = XDF_NEED_MINIMAL;
 266        memset(&xecfg, 0, sizeof(xecfg));
 267        xecfg.ctxlen = 3;
 268        ecb.outf = outf;
 269        xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 270
 271        free(minus.ptr);
 272        free(plus.ptr);
 273        return 0;
 274}
 275
 276static int copy_file(const char *src, const char *dest)
 277{
 278        FILE *in, *out;
 279        char buffer[32768];
 280        int count;
 281
 282        if (!(in = fopen(src, "r")))
 283                return error("Could not open %s", src);
 284        if (!(out = fopen(dest, "w")))
 285                return error("Could not open %s", dest);
 286        while ((count = fread(buffer, 1, sizeof(buffer), in)))
 287                fwrite(buffer, 1, count, out);
 288        fclose(in);
 289        fclose(out);
 290        return 0;
 291}
 292
 293static int do_plain_rerere(struct path_list *rr, int fd)
 294{
 295        struct path_list conflict = { NULL, 0, 0, 1 };
 296        int i;
 297
 298        find_conflict(&conflict);
 299
 300        /*
 301         * MERGE_RR records paths with conflicts immediately after merge
 302         * failed.  Some of the conflicted paths might have been hand resolved
 303         * in the working tree since then, but the initial run would catch all
 304         * and register their preimages.
 305         */
 306
 307        for (i = 0; i < conflict.nr; i++) {
 308                const char *path = conflict.items[i].path;
 309                if (!path_list_has_path(rr, path)) {
 310                        unsigned char sha1[20];
 311                        char *hex;
 312                        int ret;
 313                        ret = handle_file(path, sha1, NULL);
 314                        if (ret < 1)
 315                                continue;
 316                        hex = xstrdup(sha1_to_hex(sha1));
 317                        path_list_insert(path, rr)->util = hex;
 318                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 319                                continue;;
 320                        handle_file(path, NULL, rr_path(hex, "preimage"));
 321                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 322                }
 323        }
 324
 325        /*
 326         * Now some of the paths that had conflicts earlier might have been
 327         * hand resolved.  Others may be similar to a conflict already that
 328         * was resolved before.
 329         */
 330
 331        for (i = 0; i < rr->nr; i++) {
 332                struct stat st;
 333                int ret;
 334                const char *path = rr->items[i].path;
 335                const char *name = (const char *)rr->items[i].util;
 336
 337                if (!stat(rr_path(name, "preimage"), &st) &&
 338                                !stat(rr_path(name, "postimage"), &st)) {
 339                        if (!merge(name, path)) {
 340                                fprintf(stderr, "Resolved '%s' using "
 341                                                "previous resolution.\n", path);
 342                                goto tail_optimization;
 343                        }
 344                }
 345
 346                /* Let's see if we have resolved it. */
 347                ret = handle_file(path, NULL, NULL);
 348                if (ret)
 349                        continue;
 350
 351                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 352                copy_file(path, rr_path(name, "postimage"));
 353tail_optimization:
 354                if (i < rr->nr - 1)
 355                        memmove(rr->items + i,
 356                                rr->items + i + 1,
 357                                sizeof(rr->items[0]) * (rr->nr - i - 1));
 358                rr->nr--;
 359                i--;
 360        }
 361
 362        return write_rr(rr, fd);
 363}
 364
 365static int git_rerere_config(const char *var, const char *value)
 366{
 367        if (!strcmp(var, "gc.rerereresolved"))
 368                cutoff_resolve = git_config_int(var, value);
 369        else if (!strcmp(var, "gc.rerereunresolved"))
 370                cutoff_noresolve = git_config_int(var, value);
 371        else if (!strcmp(var, "rerere.enabled"))
 372                rerere_enabled = git_config_bool(var, value);
 373        else
 374                return git_default_config(var, value);
 375        return 0;
 376}
 377
 378static int is_rerere_enabled(void)
 379{
 380        struct stat st;
 381        const char *rr_cache;
 382        int rr_cache_exists;
 383
 384        if (!rerere_enabled)
 385                return 0;
 386
 387        rr_cache = git_path("rr-cache");
 388        rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
 389        if (rerere_enabled < 0)
 390                return rr_cache_exists;
 391
 392        if (!rr_cache_exists &&
 393            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 394                die("Could not create directory %s", rr_cache);
 395        return 1;
 396}
 397
 398int cmd_rerere(int argc, const char **argv, const char *prefix)
 399{
 400        struct path_list merge_rr = { NULL, 0, 0, 1 };
 401        int i, fd = -1;
 402
 403        git_config(git_rerere_config);
 404        if (!is_rerere_enabled())
 405                return 0;
 406
 407        merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR"));
 408        fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
 409        read_rr(&merge_rr);
 410
 411        if (argc < 2)
 412                return do_plain_rerere(&merge_rr, fd);
 413        else if (!strcmp(argv[1], "clear")) {
 414                for (i = 0; i < merge_rr.nr; i++) {
 415                        struct stat st;
 416                        const char *name = (const char *)merge_rr.items[i].util;
 417                        if (!stat(git_path("rr-cache/%s", name), &st) &&
 418                                        S_ISDIR(st.st_mode) &&
 419                                        stat(rr_path(name, "postimage"), &st))
 420                                unlink_rr_item(name);
 421                }
 422                unlink(merge_rr_path);
 423        } else if (!strcmp(argv[1], "gc"))
 424                garbage_collect(&merge_rr);
 425        else if (!strcmp(argv[1], "status"))
 426                for (i = 0; i < merge_rr.nr; i++)
 427                        printf("%s\n", merge_rr.items[i].path);
 428        else if (!strcmp(argv[1], "diff"))
 429                for (i = 0; i < merge_rr.nr; i++) {
 430                        const char *path = merge_rr.items[i].path;
 431                        const char *name = (const char *)merge_rr.items[i].util;
 432                        diff_two(rr_path(name, "preimage"), path, path, path);
 433                }
 434        else
 435                usage(git_rerere_usage);
 436
 437        path_list_clear(&merge_rr, 1);
 438        return 0;
 439}