Andrew's git - gitweb.git/blob

   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
  15static const char *rr_path(const char *name, const char *file)
  16{
  17        return git_path("rr-cache/%s/%s", name, file);
  18}
  19
  20static int has_resolution(const char *name)
  21{
  22        struct stat st;
  23        return !stat(rr_path(name, "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_in_full(out_fd, "\t", 1) != 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        char buf[1024];
  91        int hunk_no = 0;
  92        enum {
  93                RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL,
  94        } hunk = RR_CONTEXT;
  95        struct strbuf one = STRBUF_INIT, two = 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 (fgets(buf, sizeof(buf), f)) {
 115                if (!prefixcmp(buf, "<<<<<<< ")) {
 116                        if (hunk != RR_CONTEXT)
 117                                goto bad;
 118                        hunk = RR_SIDE_1;
 119                } else if (!prefixcmp(buf, "|||||||") && isspace(buf[7])) {
 120                        if (hunk != RR_SIDE_1)
 121                                goto bad;
 122                        hunk = RR_ORIGINAL;
 123                } else if (!prefixcmp(buf, "=======") && isspace(buf[7])) {
 124                        if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
 125                                goto bad;
 126                        hunk = RR_SIDE_2;
 127                } else if (!prefixcmp(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);
 151                else if (hunk == RR_ORIGINAL)
 152                        ; /* discard */
 153                else if (hunk == RR_SIDE_2)
 154                        strbuf_addstr(&two, buf);
 155                else if (out)
 156                        ferr_puts(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
 165        fclose(f);
 166        if (wrerror)
 167                error("There were errors while writing %s (%s)",
 168                      path, strerror(wrerror));
 169        if (out && fclose(out))
 170                wrerror = error("Failed to flush %s: %s",
 171                                path, strerror(errno));
 172        if (sha1)
 173                git_SHA1_Final(sha1, &ctx);
 174        if (hunk != RR_CONTEXT) {
 175                if (output)
 176                        unlink(output);
 177                return error("Could not parse conflict hunks in %s", path);
 178        }
 179        if (wrerror)
 180                return -1;
 181        return hunk_no;
 182}
 183
 184static int find_conflict(struct string_list *conflict)
 185{
 186        int i;
 187        if (read_cache() < 0)
 188                return error("Could not read index");
 189        for (i = 0; i+1 < active_nr; i++) {
 190                struct cache_entry *e2 = active_cache[i];
 191                struct cache_entry *e3 = active_cache[i+1];
 192                if (ce_stage(e2) == 2 &&
 193                    ce_stage(e3) == 3 &&
 194                    ce_same_name(e2, e3) &&
 195                    S_ISREG(e2->ce_mode) &&
 196                    S_ISREG(e3->ce_mode)) {
 197                        string_list_insert((const char *)e2->name, conflict);
 198                        i++; /* skip over both #2 and #3 */
 199                }
 200        }
 201        return 0;
 202}
 203
 204static int merge(const char *name, const char *path)
 205{
 206        int ret;
 207        mmfile_t cur, base, other;
 208        mmbuffer_t result = {NULL, 0};
 209        xpparam_t xpp = {XDF_NEED_MINIMAL};
 210
 211        if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 212                return 1;
 213
 214        if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 215                        read_mmfile(&base, rr_path(name, "preimage")) ||
 216                        read_mmfile(&other, rr_path(name, "postimage")))
 217                return 1;
 218        ret = xdl_merge(&base, &cur, "", &other, "",
 219                        &xpp, XDL_MERGE_ZEALOUS, &result);
 220        if (!ret) {
 221                FILE *f = fopen(path, "w");
 222                if (!f)
 223                        return error("Could not open %s: %s", path,
 224                                     strerror(errno));
 225                if (fwrite(result.ptr, result.size, 1, f) != 1)
 226                        error("Could not write %s: %s", path, strerror(errno));
 227                if (fclose(f))
 228                        return error("Writing %s failed: %s", path,
 229                                     strerror(errno));
 230        }
 231
 232        free(cur.ptr);
 233        free(base.ptr);
 234        free(other.ptr);
 235        free(result.ptr);
 236
 237        return ret;
 238}
 239
 240static struct lock_file index_lock;
 241
 242static int update_paths(struct string_list *update)
 243{
 244        int i;
 245        int fd = hold_locked_index(&index_lock, 0);
 246        int status = 0;
 247
 248        if (fd < 0)
 249                return -1;
 250
 251        for (i = 0; i < update->nr; i++) {
 252                struct string_list_item *item = &update->items[i];
 253                if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
 254                        status = -1;
 255        }
 256
 257        if (!status && active_cache_changed) {
 258                if (write_cache(fd, active_cache, active_nr) ||
 259                    commit_locked_index(&index_lock))
 260                        die("Unable to write new index file");
 261        } else if (fd >= 0)
 262                rollback_lock_file(&index_lock);
 263        return status;
 264}
 265
 266static int do_plain_rerere(struct string_list *rr, int fd)
 267{
 268        struct string_list conflict = { NULL, 0, 0, 1 };
 269        struct string_list update = { NULL, 0, 0, 1 };
 270        int i;
 271
 272        find_conflict(&conflict);
 273
 274        /*
 275         * MERGE_RR records paths with conflicts immediately after merge
 276         * failed.  Some of the conflicted paths might have been hand resolved
 277         * in the working tree since then, but the initial run would catch all
 278         * and register their preimages.
 279         */
 280
 281        for (i = 0; i < conflict.nr; i++) {
 282                const char *path = conflict.items[i].string;
 283                if (!string_list_has_string(rr, path)) {
 284                        unsigned char sha1[20];
 285                        char *hex;
 286                        int ret;
 287                        ret = handle_file(path, sha1, NULL);
 288                        if (ret < 1)
 289                                continue;
 290                        hex = xstrdup(sha1_to_hex(sha1));
 291                        string_list_insert(path, rr)->util = hex;
 292                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 293                                continue;;
 294                        handle_file(path, NULL, rr_path(hex, "preimage"));
 295                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 296                }
 297        }
 298
 299        /*
 300         * Now some of the paths that had conflicts earlier might have been
 301         * hand resolved.  Others may be similar to a conflict already that
 302         * was resolved before.
 303         */
 304
 305        for (i = 0; i < rr->nr; i++) {
 306                int ret;
 307                const char *path = rr->items[i].string;
 308                const char *name = (const char *)rr->items[i].util;
 309
 310                if (has_resolution(name)) {
 311                        if (!merge(name, path)) {
 312                                if (rerere_autoupdate)
 313                                        string_list_insert(path, &update);
 314                                fprintf(stderr,
 315                                        "%s '%s' using previous resolution.\n",
 316                                        rerere_autoupdate
 317                                        ? "Staged" : "Resolved",
 318                                        path);
 319                                goto mark_resolved;
 320                        }
 321                }
 322
 323                /* Let's see if we have resolved it. */
 324                ret = handle_file(path, NULL, NULL);
 325                if (ret)
 326                        continue;
 327
 328                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 329                copy_file(rr_path(name, "postimage"), path, 0666);
 330        mark_resolved:
 331                rr->items[i].util = NULL;
 332        }
 333
 334        if (update.nr)
 335                update_paths(&update);
 336
 337        return write_rr(rr, fd);
 338}
 339
 340static int git_rerere_config(const char *var, const char *value, void *cb)
 341{
 342        if (!strcmp(var, "rerere.enabled"))
 343                rerere_enabled = git_config_bool(var, value);
 344        else if (!strcmp(var, "rerere.autoupdate"))
 345                rerere_autoupdate = git_config_bool(var, value);
 346        else
 347                return git_default_config(var, value, cb);
 348        return 0;
 349}
 350
 351static int is_rerere_enabled(void)
 352{
 353        const char *rr_cache;
 354        int rr_cache_exists;
 355
 356        if (!rerere_enabled)
 357                return 0;
 358
 359        rr_cache = git_path("rr-cache");
 360        rr_cache_exists = is_directory(rr_cache);
 361        if (rerere_enabled < 0)
 362                return rr_cache_exists;
 363
 364        if (!rr_cache_exists &&
 365            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 366                die("Could not create directory %s", rr_cache);
 367        return 1;
 368}
 369
 370int setup_rerere(struct string_list *merge_rr)
 371{
 372        int fd;
 373
 374        git_config(git_rerere_config, NULL);
 375        if (!is_rerere_enabled())
 376                return -1;
 377
 378        merge_rr_path = git_pathdup("MERGE_RR");
 379        fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
 380                                       LOCK_DIE_ON_ERROR);
 381        read_rr(merge_rr);
 382        return fd;
 383}
 384
 385int rerere(void)
 386{
 387        struct string_list merge_rr = { NULL, 0, 0, 1 };
 388        int fd;
 389
 390        fd = setup_rerere(&merge_rr);
 391        if (fd < 0)
 392                return 0;
 393        return do_plain_rerere(&merge_rr, fd);
 394}