Andrew's git - gitweb.git/blob

88bb4f102c22b217ef02d064eb57ae9729daf473
   1#include "cache.h"
   2#include "string-list.h"
   3#include "rerere.h"
   4#include "xdiff/xdiff.h"
   5#include "xdiff-interface.h"
   6
   7/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
   8static int rerere_enabled = -1;
   9
  10/* automatically update cleanly resolved paths to the index */
  11static int rerere_autoupdate;
  12
  13static char *merge_rr_path;
  14
  15const char *rerere_path(const char *hex, const char *file)
  16{
  17        return git_path("rr-cache/%s/%s", hex, file);
  18}
  19
  20int has_rerere_resolution(const char *hex)
  21{
  22        struct stat st;
  23        return !stat(rerere_path(hex, "postimage"), &st);
  24}
  25
  26static void read_rr(struct string_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                string_list_insert(buf, rr)->util = name;
  47        }
  48        fclose(in);
  49}
  50
  51static struct lock_file write_lock;
  52
  53static int write_rr(struct string_list *rr, int out_fd)
  54{
  55        int i;
  56        for (i = 0; i < rr->nr; i++) {
  57                const char *path;
  58                int length;
  59                if (!rr->items[i].util)
  60                        continue;
  61                path = rr->items[i].string;
  62                length = strlen(path) + 1;
  63                if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
  64                    write_str_in_full(out_fd, "\t") != 1 ||
  65                    write_in_full(out_fd, path, length) != length)
  66                        die("unable to write rerere record");
  67        }
  68        if (commit_lock_file(&write_lock) != 0)
  69                die("unable to write rerere record");
  70        return 0;
  71}
  72
  73static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
  74{
  75        if (!count || *err)
  76                return;
  77        if (fwrite(p, count, 1, fp) != 1)
  78                *err = errno;
  79}
  80
  81static inline void ferr_puts(const char *s, FILE *fp, int *err)
  82{
  83        ferr_write(s, strlen(s), fp, err);
  84}
  85
  86static int handle_file(const char *path,
  87         unsigned char *sha1, const char *output)
  88{
  89        git_SHA_CTX ctx;
  90        int hunk_no = 0;
  91        enum {
  92                RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL,
  93        } hunk = RR_CONTEXT;
  94        struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
  95        struct strbuf buf = STRBUF_INIT;
  96        FILE *f = fopen(path, "r");
  97        FILE *out = NULL;
  98        int wrerror = 0;
  99
 100        if (!f)
 101                return error("Could not open %s", path);
 102
 103        if (output) {
 104                out = fopen(output, "w");
 105                if (!out) {
 106                        fclose(f);
 107                        return error("Could not write %s", output);
 108                }
 109        }
 110
 111        if (sha1)
 112                git_SHA1_Init(&ctx);
 113
 114        while (!strbuf_getwholeline(&buf, f, '\n')) {
 115                if (!prefixcmp(buf.buf, "<<<<<<< ")) {
 116                        if (hunk != RR_CONTEXT)
 117                                goto bad;
 118                        hunk = RR_SIDE_1;
 119                } else if (!prefixcmp(buf.buf, "|||||||") && isspace(buf.buf[7])) {
 120                        if (hunk != RR_SIDE_1)
 121                                goto bad;
 122                        hunk = RR_ORIGINAL;
 123                } else if (!prefixcmp(buf.buf, "=======") && isspace(buf.buf[7])) {
 124                        if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
 125                                goto bad;
 126                        hunk = RR_SIDE_2;
 127                } else if (!prefixcmp(buf.buf, ">>>>>>> ")) {
 128                        if (hunk != RR_SIDE_2)
 129                                goto bad;
 130                        if (strbuf_cmp(&one, &two) > 0)
 131                                strbuf_swap(&one, &two);
 132                        hunk_no++;
 133                        hunk = RR_CONTEXT;
 134                        if (out) {
 135                                ferr_puts("<<<<<<<\n", out, &wrerror);
 136                                ferr_write(one.buf, one.len, out, &wrerror);
 137                                ferr_puts("=======\n", out, &wrerror);
 138                                ferr_write(two.buf, two.len, out, &wrerror);
 139                                ferr_puts(">>>>>>>\n", out, &wrerror);
 140                        }
 141                        if (sha1) {
 142                                git_SHA1_Update(&ctx, one.buf ? one.buf : "",
 143                                            one.len + 1);
 144                                git_SHA1_Update(&ctx, two.buf ? two.buf : "",
 145                                            two.len + 1);
 146                        }
 147                        strbuf_reset(&one);
 148                        strbuf_reset(&two);
 149                } else if (hunk == RR_SIDE_1)
 150                        strbuf_addstr(&one, buf.buf);
 151                else if (hunk == RR_ORIGINAL)
 152                        ; /* discard */
 153                else if (hunk == RR_SIDE_2)
 154                        strbuf_addstr(&two, buf.buf);
 155                else if (out)
 156                        ferr_puts(buf.buf, out, &wrerror);
 157                continue;
 158        bad:
 159                hunk = 99; /* force error exit */
 160                break;
 161        }
 162        strbuf_release(&one);
 163        strbuf_release(&two);
 164        strbuf_release(&buf);
 165
 166        fclose(f);
 167        if (wrerror)
 168                error("There were errors while writing %s (%s)",
 169                      path, strerror(wrerror));
 170        if (out && fclose(out))
 171                wrerror = error("Failed to flush %s: %s",
 172                                path, strerror(errno));
 173        if (sha1)
 174                git_SHA1_Final(sha1, &ctx);
 175        if (hunk != RR_CONTEXT) {
 176                if (output)
 177                        unlink_or_warn(output);
 178                return error("Could not parse conflict hunks in %s", path);
 179        }
 180        if (wrerror)
 181                return -1;
 182        return hunk_no;
 183}
 184
 185static int find_conflict(struct string_list *conflict)
 186{
 187        int i;
 188        if (read_cache() < 0)
 189                return error("Could not read index");
 190        for (i = 0; i+1 < active_nr; i++) {
 191                struct cache_entry *e2 = active_cache[i];
 192                struct cache_entry *e3 = active_cache[i+1];
 193                if (ce_stage(e2) == 2 &&
 194                    ce_stage(e3) == 3 &&
 195                    ce_same_name(e2, e3) &&
 196                    S_ISREG(e2->ce_mode) &&
 197                    S_ISREG(e3->ce_mode)) {
 198                        string_list_insert((const char *)e2->name, conflict);
 199                        i++; /* skip over both #2 and #3 */
 200                }
 201        }
 202        return 0;
 203}
 204
 205static int merge(const char *name, const char *path)
 206{
 207        int ret;
 208        mmfile_t cur, base, other;
 209        mmbuffer_t result = {NULL, 0};
 210        xpparam_t xpp = {XDF_NEED_MINIMAL};
 211
 212        if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
 213                return 1;
 214
 215        if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
 216                        read_mmfile(&base, rerere_path(name, "preimage")) ||
 217                        read_mmfile(&other, rerere_path(name, "postimage")))
 218                return 1;
 219        ret = xdl_merge(&base, &cur, "", &other, "",
 220                        &xpp, XDL_MERGE_ZEALOUS, &result);
 221        if (!ret) {
 222                FILE *f = fopen(path, "w");
 223                if (!f)
 224                        return error("Could not open %s: %s", path,
 225                                     strerror(errno));
 226                if (fwrite(result.ptr, result.size, 1, f) != 1)
 227                        error("Could not write %s: %s", path, strerror(errno));
 228                if (fclose(f))
 229                        return error("Writing %s failed: %s", path,
 230                                     strerror(errno));
 231        }
 232
 233        free(cur.ptr);
 234        free(base.ptr);
 235        free(other.ptr);
 236        free(result.ptr);
 237
 238        return ret;
 239}
 240
 241static struct lock_file index_lock;
 242
 243static int update_paths(struct string_list *update)
 244{
 245        int i;
 246        int fd = hold_locked_index(&index_lock, 0);
 247        int status = 0;
 248
 249        if (fd < 0)
 250                return -1;
 251
 252        for (i = 0; i < update->nr; i++) {
 253                struct string_list_item *item = &update->items[i];
 254                if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
 255                        status = -1;
 256        }
 257
 258        if (!status && active_cache_changed) {
 259                if (write_cache(fd, active_cache, active_nr) ||
 260                    commit_locked_index(&index_lock))
 261                        die("Unable to write new index file");
 262        } else if (fd >= 0)
 263                rollback_lock_file(&index_lock);
 264        return status;
 265}
 266
 267static int do_plain_rerere(struct string_list *rr, int fd)
 268{
 269        struct string_list conflict = { NULL, 0, 0, 1 };
 270        struct string_list update = { NULL, 0, 0, 1 };
 271        int i;
 272
 273        find_conflict(&conflict);
 274
 275        /*
 276         * MERGE_RR records paths with conflicts immediately after merge
 277         * failed.  Some of the conflicted paths might have been hand resolved
 278         * in the working tree since then, but the initial run would catch all
 279         * and register their preimages.
 280         */
 281
 282        for (i = 0; i < conflict.nr; i++) {
 283                const char *path = conflict.items[i].string;
 284                if (!string_list_has_string(rr, path)) {
 285                        unsigned char sha1[20];
 286                        char *hex;
 287                        int ret;
 288                        ret = handle_file(path, sha1, NULL);
 289                        if (ret < 1)
 290                                continue;
 291                        hex = xstrdup(sha1_to_hex(sha1));
 292                        string_list_insert(path, rr)->util = hex;
 293                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 294                                continue;
 295                        handle_file(path, NULL, rerere_path(hex, "preimage"));
 296                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 297                }
 298        }
 299
 300        /*
 301         * Now some of the paths that had conflicts earlier might have been
 302         * hand resolved.  Others may be similar to a conflict already that
 303         * was resolved before.
 304         */
 305
 306        for (i = 0; i < rr->nr; i++) {
 307                int ret;
 308                const char *path = rr->items[i].string;
 309                const char *name = (const char *)rr->items[i].util;
 310
 311                if (has_rerere_resolution(name)) {
 312                        if (!merge(name, path)) {
 313                                if (rerere_autoupdate)
 314                                        string_list_insert(path, &update);
 315                                fprintf(stderr,
 316                                        "%s '%s' using previous resolution.\n",
 317                                        rerere_autoupdate
 318                                        ? "Staged" : "Resolved",
 319                                        path);
 320                                goto mark_resolved;
 321                        }
 322                }
 323
 324                /* Let's see if we have resolved it. */
 325                ret = handle_file(path, NULL, NULL);
 326                if (ret)
 327                        continue;
 328
 329                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 330                copy_file(rerere_path(name, "postimage"), path, 0666);
 331        mark_resolved:
 332                rr->items[i].util = NULL;
 333        }
 334
 335        if (update.nr)
 336                update_paths(&update);
 337
 338        return write_rr(rr, fd);
 339}
 340
 341static int git_rerere_config(const char *var, const char *value, void *cb)
 342{
 343        if (!strcmp(var, "rerere.enabled"))
 344                rerere_enabled = git_config_bool(var, value);
 345        else if (!strcmp(var, "rerere.autoupdate"))
 346                rerere_autoupdate = git_config_bool(var, value);
 347        else
 348                return git_default_config(var, value, cb);
 349        return 0;
 350}
 351
 352static int is_rerere_enabled(void)
 353{
 354        const char *rr_cache;
 355        int rr_cache_exists;
 356
 357        if (!rerere_enabled)
 358                return 0;
 359
 360        rr_cache = git_path("rr-cache");
 361        rr_cache_exists = is_directory(rr_cache);
 362        if (rerere_enabled < 0)
 363                return rr_cache_exists;
 364
 365        if (!rr_cache_exists &&
 366            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 367                die("Could not create directory %s", rr_cache);
 368        return 1;
 369}
 370
 371int setup_rerere(struct string_list *merge_rr)
 372{
 373        int fd;
 374
 375        git_config(git_rerere_config, NULL);
 376        if (!is_rerere_enabled())
 377                return -1;
 378
 379        merge_rr_path = git_pathdup("MERGE_RR");
 380        fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
 381                                       LOCK_DIE_ON_ERROR);
 382        read_rr(merge_rr);
 383        return fd;
 384}
 385
 386int rerere(void)
 387{
 388        struct string_list merge_rr = { NULL, 0, 0, 1 };
 389        int fd;
 390
 391        fd = setup_rerere(&merge_rr);
 392        if (fd < 0)
 393                return 0;
 394        return do_plain_rerere(&merge_rr, fd);
 395}