Andrew's git - gitweb.git/blob

db1d42f1b61777c0099de01c4e917a57e1f68dca
   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
  86struct rerere_io {
  87        int (*getline)(struct strbuf *, struct rerere_io *);
  88        FILE *output;
  89        int wrerror;
  90        /* some more stuff */
  91};
  92
  93static void rerere_io_putstr(const char *str, struct rerere_io *io)
  94{
  95        if (io->output)
  96                ferr_puts(str, io->output, &io->wrerror);
  97}
  98
  99static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
 100{
 101        if (io->output)
 102                ferr_write(mem, sz, io->output, &io->wrerror);
 103}
 104
 105struct rerere_io_file {
 106        struct rerere_io io;
 107        FILE *input;
 108};
 109
 110static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
 111{
 112        struct rerere_io_file *io = (struct rerere_io_file *)io_;
 113        return strbuf_getwholeline(sb, io->input, '\n');
 114}
 115
 116static int handle_path(unsigned char *sha1, struct rerere_io *io)
 117{
 118        git_SHA_CTX ctx;
 119        int hunk_no = 0;
 120        enum {
 121                RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL,
 122        } hunk = RR_CONTEXT;
 123        struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
 124        struct strbuf buf = STRBUF_INIT;
 125
 126        if (sha1)
 127                git_SHA1_Init(&ctx);
 128
 129        while (!io->getline(&buf, io)) {
 130                if (!prefixcmp(buf.buf, "<<<<<<< ")) {
 131                        if (hunk != RR_CONTEXT)
 132                                goto bad;
 133                        hunk = RR_SIDE_1;
 134                } else if (!prefixcmp(buf.buf, "|||||||") && isspace(buf.buf[7])) {
 135                        if (hunk != RR_SIDE_1)
 136                                goto bad;
 137                        hunk = RR_ORIGINAL;
 138                } else if (!prefixcmp(buf.buf, "=======") && isspace(buf.buf[7])) {
 139                        if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
 140                                goto bad;
 141                        hunk = RR_SIDE_2;
 142                } else if (!prefixcmp(buf.buf, ">>>>>>> ")) {
 143                        if (hunk != RR_SIDE_2)
 144                                goto bad;
 145                        if (strbuf_cmp(&one, &two) > 0)
 146                                strbuf_swap(&one, &two);
 147                        hunk_no++;
 148                        hunk = RR_CONTEXT;
 149                        rerere_io_putstr("<<<<<<<\n", io);
 150                        rerere_io_putmem(one.buf, one.len, io);
 151                        rerere_io_putstr("=======\n", io);
 152                        rerere_io_putmem(two.buf, two.len, io);
 153                        rerere_io_putstr(">>>>>>>\n", io);
 154                        if (sha1) {
 155                                git_SHA1_Update(&ctx, one.buf ? one.buf : "",
 156                                            one.len + 1);
 157                                git_SHA1_Update(&ctx, two.buf ? two.buf : "",
 158                                            two.len + 1);
 159                        }
 160                        strbuf_reset(&one);
 161                        strbuf_reset(&two);
 162                } else if (hunk == RR_SIDE_1)
 163                        strbuf_addstr(&one, buf.buf);
 164                else if (hunk == RR_ORIGINAL)
 165                        ; /* discard */
 166                else if (hunk == RR_SIDE_2)
 167                        strbuf_addstr(&two, buf.buf);
 168                else
 169                        rerere_io_putstr(buf.buf, io);
 170                continue;
 171        bad:
 172                hunk = 99; /* force error exit */
 173                break;
 174        }
 175        strbuf_release(&one);
 176        strbuf_release(&two);
 177        strbuf_release(&buf);
 178
 179        if (sha1)
 180                git_SHA1_Final(sha1, &ctx);
 181        if (hunk != RR_CONTEXT)
 182                return -1;
 183        return hunk_no;
 184}
 185
 186static int handle_file(const char *path, unsigned char *sha1, const char *output)
 187{
 188        int hunk_no = 0;
 189        struct rerere_io_file io;
 190
 191        memset(&io, 0, sizeof(io));
 192        io.io.getline = rerere_file_getline;
 193        io.input = fopen(path, "r");
 194        io.io.wrerror = 0;
 195        if (!io.input)
 196                return error("Could not open %s", path);
 197
 198        if (output) {
 199                io.io.output = fopen(output, "w");
 200                if (!io.io.output) {
 201                        fclose(io.input);
 202                        return error("Could not write %s", output);
 203                }
 204        }
 205
 206        hunk_no = handle_path(sha1, (struct rerere_io *)&io);
 207
 208        fclose(io.input);
 209        if (io.io.wrerror)
 210                error("There were errors while writing %s (%s)",
 211                      path, strerror(io.io.wrerror));
 212        if (io.io.output && fclose(io.io.output))
 213                io.io.wrerror = error("Failed to flush %s: %s",
 214                                      path, strerror(errno));
 215
 216        if (hunk_no < 0) {
 217                if (output)
 218                        unlink_or_warn(output);
 219                return error("Could not parse conflict hunks in %s", path);
 220        }
 221        if (io.io.wrerror)
 222                return -1;
 223        return hunk_no;
 224}
 225
 226static int find_conflict(struct string_list *conflict)
 227{
 228        int i;
 229        if (read_cache() < 0)
 230                return error("Could not read index");
 231        for (i = 0; i+1 < active_nr; i++) {
 232                struct cache_entry *e2 = active_cache[i];
 233                struct cache_entry *e3 = active_cache[i+1];
 234                if (ce_stage(e2) == 2 &&
 235                    ce_stage(e3) == 3 &&
 236                    ce_same_name(e2, e3) &&
 237                    S_ISREG(e2->ce_mode) &&
 238                    S_ISREG(e3->ce_mode)) {
 239                        string_list_insert((const char *)e2->name, conflict);
 240                        i++; /* skip over both #2 and #3 */
 241                }
 242        }
 243        return 0;
 244}
 245
 246static int merge(const char *name, const char *path)
 247{
 248        int ret;
 249        mmfile_t cur, base, other;
 250        mmbuffer_t result = {NULL, 0};
 251        xpparam_t xpp = {XDF_NEED_MINIMAL};
 252
 253        if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
 254                return 1;
 255
 256        if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
 257                        read_mmfile(&base, rerere_path(name, "preimage")) ||
 258                        read_mmfile(&other, rerere_path(name, "postimage")))
 259                return 1;
 260        ret = xdl_merge(&base, &cur, "", &other, "",
 261                        &xpp, XDL_MERGE_ZEALOUS, &result);
 262        if (!ret) {
 263                FILE *f = fopen(path, "w");
 264                if (!f)
 265                        return error("Could not open %s: %s", path,
 266                                     strerror(errno));
 267                if (fwrite(result.ptr, result.size, 1, f) != 1)
 268                        error("Could not write %s: %s", path, strerror(errno));
 269                if (fclose(f))
 270                        return error("Writing %s failed: %s", path,
 271                                     strerror(errno));
 272        }
 273
 274        free(cur.ptr);
 275        free(base.ptr);
 276        free(other.ptr);
 277        free(result.ptr);
 278
 279        return ret;
 280}
 281
 282static struct lock_file index_lock;
 283
 284static int update_paths(struct string_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 string_list_item *item = &update->items[i];
 295                if (add_file_to_cache(item->string, 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 string_list *rr, int fd)
 309{
 310        struct string_list conflict = { NULL, 0, 0, 1 };
 311        struct string_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].string;
 325                if (!string_list_has_string(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                        string_list_insert(path, rr)->util = hex;
 334                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 335                                continue;
 336                        handle_file(path, NULL, rerere_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].string;
 350                const char *name = (const char *)rr->items[i].util;
 351
 352                if (has_rerere_resolution(name)) {
 353                        if (!merge(name, path)) {
 354                                if (rerere_autoupdate)
 355                                        string_list_insert(path, &update);
 356                                fprintf(stderr,
 357                                        "%s '%s' using previous resolution.\n",
 358                                        rerere_autoupdate
 359                                        ? "Staged" : "Resolved",
 360                                        path);
 361                                goto mark_resolved;
 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(rerere_path(name, "postimage"), path, 0666);
 372        mark_resolved:
 373                rr->items[i].util = NULL;
 374        }
 375
 376        if (update.nr)
 377                update_paths(&update);
 378
 379        return write_rr(rr, fd);
 380}
 381
 382static int git_rerere_config(const char *var, const char *value, void *cb)
 383{
 384        if (!strcmp(var, "rerere.enabled"))
 385                rerere_enabled = git_config_bool(var, value);
 386        else if (!strcmp(var, "rerere.autoupdate"))
 387                rerere_autoupdate = git_config_bool(var, value);
 388        else
 389                return git_default_config(var, value, cb);
 390        return 0;
 391}
 392
 393static int is_rerere_enabled(void)
 394{
 395        const char *rr_cache;
 396        int rr_cache_exists;
 397
 398        if (!rerere_enabled)
 399                return 0;
 400
 401        rr_cache = git_path("rr-cache");
 402        rr_cache_exists = is_directory(rr_cache);
 403        if (rerere_enabled < 0)
 404                return rr_cache_exists;
 405
 406        if (!rr_cache_exists &&
 407            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 408                die("Could not create directory %s", rr_cache);
 409        return 1;
 410}
 411
 412int setup_rerere(struct string_list *merge_rr)
 413{
 414        int fd;
 415
 416        git_config(git_rerere_config, NULL);
 417        if (!is_rerere_enabled())
 418                return -1;
 419
 420        merge_rr_path = git_pathdup("MERGE_RR");
 421        fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
 422                                       LOCK_DIE_ON_ERROR);
 423        read_rr(merge_rr);
 424        return fd;
 425}
 426
 427int rerere(void)
 428{
 429        struct string_list merge_rr = { NULL, 0, 0, 1 };
 430        int fd;
 431
 432        fd = setup_rerere(&merge_rr);
 433        if (fd < 0)
 434                return 0;
 435        return do_plain_rerere(&merge_rr, fd);
 436}