Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "path-list.h"
   3#include "xdiff/xdiff.h"
   4#include "xdiff-interface.h"
   5
   6#include <time.h>
   7
   8static const char git_rerere_usage[] =
   9"git-rerere [clear | status | diff | gc]";
  10
  11/* these values are days */
  12static int cutoff_noresolve = 15;
  13static int cutoff_resolve = 60;
  14
  15/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
  16static int rerere_enabled = -1;
  17
  18static char *merge_rr_path;
  19
  20static const char *rr_path(const char *name, const char *file)
  21{
  22        return git_path("rr-cache/%s/%s", name, file);
  23}
  24
  25static void read_rr(struct path_list *rr)
  26{
  27        unsigned char sha1[20];
  28        char buf[PATH_MAX];
  29        FILE *in = fopen(merge_rr_path, "r");
  30        if (!in)
  31                return;
  32        while (fread(buf, 40, 1, in) == 1) {
  33                int i;
  34                char *name;
  35                if (get_sha1_hex(buf, sha1))
  36                        die("corrupt MERGE_RR");
  37                buf[40] = '\0';
  38                name = xstrdup(buf);
  39                if (fgetc(in) != '\t')
  40                        die("corrupt MERGE_RR");
  41                for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
  42                        ; /* do nothing */
  43                if (i == sizeof(buf))
  44                        die("filename too long");
  45                path_list_insert(buf, rr)->util = xstrdup(name);
  46        }
  47        fclose(in);
  48}
  49
  50static struct lock_file write_lock;
  51
  52static int write_rr(struct path_list *rr, int out_fd)
  53{
  54        int i;
  55        for (i = 0; i < rr->nr; i++) {
  56                const char *path = rr->items[i].path;
  57                int length = strlen(path) + 1;
  58                if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
  59                    write_in_full(out_fd, "\t", 1) != 1 ||
  60                    write_in_full(out_fd, path, length) != length)
  61                        die("unable to write rerere record");
  62        }
  63        if (close(out_fd) != 0)
  64                die("unable to write rerere record");
  65        return commit_lock_file(&write_lock);
  66}
  67
  68struct buffer {
  69        char *ptr;
  70        int nr, alloc;
  71};
  72
  73static void append_line(struct buffer *buffer, const char *line)
  74{
  75        int len = strlen(line);
  76
  77        if (buffer->nr + len > buffer->alloc) {
  78                buffer->alloc = alloc_nr(buffer->nr + len);
  79                buffer->ptr = xrealloc(buffer->ptr, buffer->alloc);
  80        }
  81        memcpy(buffer->ptr + buffer->nr, line, len);
  82        buffer->nr += len;
  83}
  84
  85static void clear_buffer(struct buffer *buffer)
  86{
  87        free(buffer->ptr);
  88        buffer->ptr = NULL;
  89        buffer->nr = buffer->alloc = 0;
  90}
  91
  92static int handle_file(const char *path,
  93         unsigned char *sha1, const char *output)
  94{
  95        SHA_CTX ctx;
  96        char buf[1024];
  97        int hunk = 0, hunk_no = 0;
  98        struct buffer minus = { NULL, 0, 0 }, plus = { NULL, 0, 0 };
  99        struct buffer *one = &minus, *two = &plus;
 100        FILE *f = fopen(path, "r");
 101        FILE *out;
 102
 103        if (!f)
 104                return error("Could not open %s", path);
 105
 106        if (output) {
 107                out = fopen(output, "w");
 108                if (!out) {
 109                        fclose(f);
 110                        return error("Could not write %s", output);
 111                }
 112        } else
 113                out = NULL;
 114
 115        if (sha1)
 116                SHA1_Init(&ctx);
 117
 118        while (fgets(buf, sizeof(buf), f)) {
 119                if (!prefixcmp(buf, "<<<<<<< "))
 120                        hunk = 1;
 121                else if (!prefixcmp(buf, "======="))
 122                        hunk = 2;
 123                else if (!prefixcmp(buf, ">>>>>>> ")) {
 124                        int one_is_longer = (one->nr > two->nr);
 125                        int common_len = one_is_longer ? two->nr : one->nr;
 126                        int cmp = memcmp(one->ptr, two->ptr, common_len);
 127
 128                        hunk_no++;
 129                        hunk = 0;
 130                        if ((cmp > 0) || ((cmp == 0) && one_is_longer)) {
 131                                struct buffer *swap = one;
 132                                one = two;
 133                                two = swap;
 134                        }
 135                        if (out) {
 136                                fputs("<<<<<<<\n", out);
 137                                fwrite(one->ptr, one->nr, 1, out);
 138                                fputs("=======\n", out);
 139                                fwrite(two->ptr, two->nr, 1, out);
 140                                fputs(">>>>>>>\n", out);
 141                        }
 142                        if (sha1) {
 143                                SHA1_Update(&ctx, one->ptr, one->nr);
 144                                SHA1_Update(&ctx, "\0", 1);
 145                                SHA1_Update(&ctx, two->ptr, two->nr);
 146                                SHA1_Update(&ctx, "\0", 1);
 147                        }
 148                        clear_buffer(one);
 149                        clear_buffer(two);
 150                } else if (hunk == 1)
 151                        append_line(one, buf);
 152                else if (hunk == 2)
 153                        append_line(two, buf);
 154                else if (out)
 155                        fputs(buf, out);
 156        }
 157
 158        fclose(f);
 159        if (out)
 160                fclose(out);
 161        if (sha1)
 162                SHA1_Final(sha1, &ctx);
 163        return hunk_no;
 164}
 165
 166static int find_conflict(struct path_list *conflict)
 167{
 168        int i;
 169        if (read_cache() < 0)
 170                return error("Could not read index");
 171        for (i = 0; i+1 < active_nr; i++) {
 172                struct cache_entry *e2 = active_cache[i];
 173                struct cache_entry *e3 = active_cache[i+1];
 174                if (ce_stage(e2) == 2 &&
 175                    ce_stage(e3) == 3 &&
 176                    ce_same_name(e2, e3) &&
 177                    S_ISREG(ntohl(e2->ce_mode)) &&
 178                    S_ISREG(ntohl(e3->ce_mode))) {
 179                        path_list_insert((const char *)e2->name, conflict);
 180                        i++; /* skip over both #2 and #3 */
 181                }
 182        }
 183        return 0;
 184}
 185
 186static int merge(const char *name, const char *path)
 187{
 188        int ret;
 189        mmfile_t cur, base, other;
 190        mmbuffer_t result = {NULL, 0};
 191        xpparam_t xpp = {XDF_NEED_MINIMAL};
 192
 193        if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 194                return 1;
 195
 196        if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 197                        read_mmfile(&base, rr_path(name, "preimage")) ||
 198                        read_mmfile(&other, rr_path(name, "postimage")))
 199                return 1;
 200        ret = xdl_merge(&base, &cur, "", &other, "",
 201                        &xpp, XDL_MERGE_ZEALOUS, &result);
 202        if (!ret) {
 203                FILE *f = fopen(path, "w");
 204                if (!f)
 205                        return error("Could not write to %s", path);
 206                fwrite(result.ptr, result.size, 1, f);
 207                fclose(f);
 208        }
 209
 210        free(cur.ptr);
 211        free(base.ptr);
 212        free(other.ptr);
 213        free(result.ptr);
 214
 215        return ret;
 216}
 217
 218static void unlink_rr_item(const char *name)
 219{
 220        unlink(rr_path(name, "thisimage"));
 221        unlink(rr_path(name, "preimage"));
 222        unlink(rr_path(name, "postimage"));
 223        rmdir(git_path("rr-cache/%s", name));
 224}
 225
 226static void garbage_collect(struct path_list *rr)
 227{
 228        struct path_list to_remove = { NULL, 0, 0, 1 };
 229        char buf[1024];
 230        DIR *dir;
 231        struct dirent *e;
 232        int len, i, cutoff;
 233        time_t now = time(NULL), then;
 234
 235        strlcpy(buf, git_path("rr-cache"), sizeof(buf));
 236        len = strlen(buf);
 237        dir = opendir(buf);
 238        strcpy(buf + len++, "/");
 239        while ((e = readdir(dir))) {
 240                const char *name = e->d_name;
 241                struct stat st;
 242                if (name[0] == '.' && (name[1] == '\0' ||
 243                                        (name[1] == '.' && name[2] == '\0')))
 244                        continue;
 245                i = snprintf(buf + len, sizeof(buf) - len, "%s", name);
 246                strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i);
 247                if (stat(buf, &st))
 248                        continue;
 249                then = st.st_mtime;
 250                strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i);
 251                cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve;
 252                if (then < now - cutoff * 86400) {
 253                        buf[len + i] = '\0';
 254                        path_list_insert(xstrdup(name), &to_remove);
 255                }
 256        }
 257        for (i = 0; i < to_remove.nr; i++)
 258                unlink_rr_item(to_remove.items[i].path);
 259        path_list_clear(&to_remove, 0);
 260}
 261
 262static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
 263{
 264        int i;
 265        for (i = 0; i < nbuf; i++)
 266                if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
 267                        return -1;
 268        return 0;
 269}
 270
 271static int diff_two(const char *file1, const char *label1,
 272                const char *file2, const char *label2)
 273{
 274        xpparam_t xpp;
 275        xdemitconf_t xecfg;
 276        xdemitcb_t ecb;
 277        mmfile_t minus, plus;
 278
 279        if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
 280                return 1;
 281
 282        printf("--- a/%s\n+++ b/%s\n", label1, label2);
 283        fflush(stdout);
 284        xpp.flags = XDF_NEED_MINIMAL;
 285        memset(&xecfg, 0, sizeof(xecfg));
 286        xecfg.ctxlen = 3;
 287        ecb.outf = outf;
 288        xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 289
 290        free(minus.ptr);
 291        free(plus.ptr);
 292        return 0;
 293}
 294
 295static int copy_file(const char *src, const char *dest)
 296{
 297        FILE *in, *out;
 298        char buffer[32768];
 299        int count;
 300
 301        if (!(in = fopen(src, "r")))
 302                return error("Could not open %s", src);
 303        if (!(out = fopen(dest, "w")))
 304                return error("Could not open %s", dest);
 305        while ((count = fread(buffer, 1, sizeof(buffer), in)))
 306                fwrite(buffer, 1, count, out);
 307        fclose(in);
 308        fclose(out);
 309        return 0;
 310}
 311
 312static int do_plain_rerere(struct path_list *rr, int fd)
 313{
 314        struct path_list conflict = { NULL, 0, 0, 1 };
 315        int i;
 316
 317        find_conflict(&conflict);
 318
 319        /*
 320         * MERGE_RR records paths with conflicts immediately after merge
 321         * failed.  Some of the conflicted paths might have been hand resolved
 322         * in the working tree since then, but the initial run would catch all
 323         * and register their preimages.
 324         */
 325
 326        for (i = 0; i < conflict.nr; i++) {
 327                const char *path = conflict.items[i].path;
 328                if (!path_list_has_path(rr, path)) {
 329                        unsigned char sha1[20];
 330                        char *hex;
 331                        int ret;
 332                        ret = handle_file(path, sha1, NULL);
 333                        if (ret < 1)
 334                                continue;
 335                        hex = xstrdup(sha1_to_hex(sha1));
 336                        path_list_insert(path, rr)->util = hex;
 337                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 338                                continue;;
 339                        handle_file(path, NULL, rr_path(hex, "preimage"));
 340                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 341                }
 342        }
 343
 344        /*
 345         * Now some of the paths that had conflicts earlier might have been
 346         * hand resolved.  Others may be similar to a conflict already that
 347         * was resolved before.
 348         */
 349
 350        for (i = 0; i < rr->nr; i++) {
 351                struct stat st;
 352                int ret;
 353                const char *path = rr->items[i].path;
 354                const char *name = (const char *)rr->items[i].util;
 355
 356                if (!stat(rr_path(name, "preimage"), &st) &&
 357                                !stat(rr_path(name, "postimage"), &st)) {
 358                        if (!merge(name, path)) {
 359                                fprintf(stderr, "Resolved '%s' using "
 360                                                "previous resolution.\n", path);
 361                                goto tail_optimization;
 362                        }
 363                }
 364
 365                /* Let's see if we have resolved it. */
 366                ret = handle_file(path, NULL, NULL);
 367                if (ret)
 368                        continue;
 369
 370                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 371                copy_file(path, rr_path(name, "postimage"));
 372tail_optimization:
 373                if (i < rr->nr - 1)
 374                        memmove(rr->items + i,
 375                                rr->items + i + 1,
 376                                sizeof(rr->items[0]) * (rr->nr - i - 1));
 377                rr->nr--;
 378                i--;
 379        }
 380
 381        return write_rr(rr, fd);
 382}
 383
 384static int git_rerere_config(const char *var, const char *value)
 385{
 386        if (!strcmp(var, "gc.rerereresolved"))
 387                cutoff_resolve = git_config_int(var, value);
 388        else if (!strcmp(var, "gc.rerereunresolved"))
 389                cutoff_noresolve = git_config_int(var, value);
 390        else if (!strcmp(var, "rerere.enabled"))
 391                rerere_enabled = git_config_bool(var, value);
 392        else
 393                return git_default_config(var, value);
 394        return 0;
 395}
 396
 397static int is_rerere_enabled(void)
 398{
 399        struct stat st;
 400        const char *rr_cache;
 401        int rr_cache_exists;
 402
 403        if (!rerere_enabled)
 404                return 0;
 405
 406        rr_cache = git_path("rr-cache");
 407        rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
 408        if (rerere_enabled < 0)
 409                return rr_cache_exists;
 410
 411        if (!rr_cache_exists &&
 412            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 413                die("Could not create directory %s", rr_cache);
 414        return 1;
 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 = -1;
 421
 422        git_config(git_rerere_config);
 423        if (!is_rerere_enabled())
 424                return 0;
 425
 426        merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR"));
 427        fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
 428        read_rr(&merge_rr);
 429
 430        if (argc < 2)
 431                return do_plain_rerere(&merge_rr, fd);
 432        else if (!strcmp(argv[1], "clear")) {
 433                for (i = 0; i < merge_rr.nr; i++) {
 434                        struct stat st;
 435                        const char *name = (const char *)merge_rr.items[i].util;
 436                        if (!stat(git_path("rr-cache/%s", name), &st) &&
 437                                        S_ISDIR(st.st_mode) &&
 438                                        stat(rr_path(name, "postimage"), &st))
 439                                unlink_rr_item(name);
 440                }
 441                unlink(merge_rr_path);
 442        } else if (!strcmp(argv[1], "gc"))
 443                garbage_collect(&merge_rr);
 444        else if (!strcmp(argv[1], "status"))
 445                for (i = 0; i < merge_rr.nr; i++)
 446                        printf("%s\n", merge_rr.items[i].path);
 447        else if (!strcmp(argv[1], "diff"))
 448                for (i = 0; i < merge_rr.nr; i++) {
 449                        const char *path = merge_rr.items[i].path;
 450                        const char *name = (const char *)merge_rr.items[i].util;
 451                        diff_two(rr_path(name, "preimage"), path, path, path);
 452                }
 453        else
 454                usage(git_rerere_usage);
 455
 456        path_list_clear(&merge_rr, 1);
 457        return 0;
 458}