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