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 int handle_file(const char *path,
  74         unsigned char *sha1, const char *output)
  75{
  76        git_SHA_CTX ctx;
  77        char buf[1024];
  78        int hunk_no = 0;
  79        enum {
  80                RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL,
  81        } hunk = RR_CONTEXT;
  82        struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
  83        FILE *f = fopen(path, "r");
  84        FILE *out = NULL;
  85
  86        if (!f)
  87                return error("Could not open %s", path);
  88
  89        if (output) {
  90                out = fopen(output, "w");
  91                if (!out) {
  92                        fclose(f);
  93                        return error("Could not write %s", output);
  94                }
  95        }
  96
  97        if (sha1)
  98                git_SHA1_Init(&ctx);
  99
 100        while (fgets(buf, sizeof(buf), f)) {
 101                if (!prefixcmp(buf, "<<<<<<< ")) {
 102                        if (hunk != RR_CONTEXT)
 103                                goto bad;
 104                        hunk = RR_SIDE_1;
 105                } else if (!prefixcmp(buf, "|||||||") && isspace(buf[7])) {
 106                        if (hunk != RR_SIDE_1)
 107                                goto bad;
 108                        hunk = RR_ORIGINAL;
 109                } else if (!prefixcmp(buf, "=======") && isspace(buf[7])) {
 110                        if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
 111                                goto bad;
 112                        hunk = RR_SIDE_2;
 113                } else if (!prefixcmp(buf, ">>>>>>> ")) {
 114                        if (hunk != RR_SIDE_2)
 115                                goto bad;
 116                        if (strbuf_cmp(&one, &two) > 0)
 117                                strbuf_swap(&one, &two);
 118                        hunk_no++;
 119                        hunk = RR_CONTEXT;
 120                        if (out) {
 121                                fputs("<<<<<<<\n", out);
 122                                fwrite(one.buf, one.len, 1, out);
 123                                fputs("=======\n", out);
 124                                fwrite(two.buf, two.len, 1, out);
 125                                fputs(">>>>>>>\n", out);
 126                        }
 127                        if (sha1) {
 128                                git_SHA1_Update(&ctx, one.buf ? one.buf : "",
 129                                            one.len + 1);
 130                                git_SHA1_Update(&ctx, two.buf ? two.buf : "",
 131                                            two.len + 1);
 132                        }
 133                        strbuf_reset(&one);
 134                        strbuf_reset(&two);
 135                } else if (hunk == RR_SIDE_1)
 136                        strbuf_addstr(&one, buf);
 137                else if (hunk == RR_ORIGINAL)
 138                        ; /* discard */
 139                else if (hunk == RR_SIDE_2)
 140                        strbuf_addstr(&two, buf);
 141                else if (out)
 142                        fputs(buf, out);
 143                continue;
 144        bad:
 145                hunk = 99; /* force error exit */
 146                break;
 147        }
 148        strbuf_release(&one);
 149        strbuf_release(&two);
 150
 151        fclose(f);
 152        if (out)
 153                fclose(out);
 154        if (sha1)
 155                git_SHA1_Final(sha1, &ctx);
 156        if (hunk != RR_CONTEXT) {
 157                if (output)
 158                        unlink(output);
 159                return error("Could not parse conflict hunks in %s", path);
 160        }
 161        return hunk_no;
 162}
 163
 164static int find_conflict(struct string_list *conflict)
 165{
 166        int i;
 167        if (read_cache() < 0)
 168                return error("Could not read index");
 169        for (i = 0; i+1 < active_nr; i++) {
 170                struct cache_entry *e2 = active_cache[i];
 171                struct cache_entry *e3 = active_cache[i+1];
 172                if (ce_stage(e2) == 2 &&
 173                    ce_stage(e3) == 3 &&
 174                    ce_same_name(e2, e3) &&
 175                    S_ISREG(e2->ce_mode) &&
 176                    S_ISREG(e3->ce_mode)) {
 177                        string_list_insert((const char *)e2->name, conflict);
 178                        i++; /* skip over both #2 and #3 */
 179                }
 180        }
 181        return 0;
 182}
 183
 184static int merge(const char *name, const char *path)
 185{
 186        int ret;
 187        mmfile_t cur, base, other;
 188        mmbuffer_t result = {NULL, 0};
 189        xpparam_t xpp = {XDF_NEED_MINIMAL};
 190
 191        if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 192                return 1;
 193
 194        if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 195                        read_mmfile(&base, rr_path(name, "preimage")) ||
 196                        read_mmfile(&other, rr_path(name, "postimage")))
 197                return 1;
 198        ret = xdl_merge(&base, &cur, "", &other, "",
 199                        &xpp, XDL_MERGE_ZEALOUS, &result);
 200        if (!ret) {
 201                FILE *f = fopen(path, "w");
 202                if (!f)
 203                        return error("Could not write to %s", path);
 204                fwrite(result.ptr, result.size, 1, f);
 205                fclose(f);
 206        }
 207
 208        free(cur.ptr);
 209        free(base.ptr);
 210        free(other.ptr);
 211        free(result.ptr);
 212
 213        return ret;
 214}
 215
 216static struct lock_file index_lock;
 217
 218static int update_paths(struct string_list *update)
 219{
 220        int i;
 221        int fd = hold_locked_index(&index_lock, 0);
 222        int status = 0;
 223
 224        if (fd < 0)
 225                return -1;
 226
 227        for (i = 0; i < update->nr; i++) {
 228                struct string_list_item *item = &update->items[i];
 229                if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
 230                        status = -1;
 231        }
 232
 233        if (!status && active_cache_changed) {
 234                if (write_cache(fd, active_cache, active_nr) ||
 235                    commit_locked_index(&index_lock))
 236                        die("Unable to write new index file");
 237        } else if (fd >= 0)
 238                rollback_lock_file(&index_lock);
 239        return status;
 240}
 241
 242static int do_plain_rerere(struct string_list *rr, int fd)
 243{
 244        struct string_list conflict = { NULL, 0, 0, 1 };
 245        struct string_list update = { NULL, 0, 0, 1 };
 246        int i;
 247
 248        find_conflict(&conflict);
 249
 250        /*
 251         * MERGE_RR records paths with conflicts immediately after merge
 252         * failed.  Some of the conflicted paths might have been hand resolved
 253         * in the working tree since then, but the initial run would catch all
 254         * and register their preimages.
 255         */
 256
 257        for (i = 0; i < conflict.nr; i++) {
 258                const char *path = conflict.items[i].string;
 259                if (!string_list_has_string(rr, path)) {
 260                        unsigned char sha1[20];
 261                        char *hex;
 262                        int ret;
 263                        ret = handle_file(path, sha1, NULL);
 264                        if (ret < 1)
 265                                continue;
 266                        hex = xstrdup(sha1_to_hex(sha1));
 267                        string_list_insert(path, rr)->util = hex;
 268                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 269                                continue;;
 270                        handle_file(path, NULL, rr_path(hex, "preimage"));
 271                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 272                }
 273        }
 274
 275        /*
 276         * Now some of the paths that had conflicts earlier might have been
 277         * hand resolved.  Others may be similar to a conflict already that
 278         * was resolved before.
 279         */
 280
 281        for (i = 0; i < rr->nr; i++) {
 282                int ret;
 283                const char *path = rr->items[i].string;
 284                const char *name = (const char *)rr->items[i].util;
 285
 286                if (has_resolution(name)) {
 287                        if (!merge(name, path)) {
 288                                if (rerere_autoupdate)
 289                                        string_list_insert(path, &update);
 290                                fprintf(stderr,
 291                                        "%s '%s' using previous resolution.\n",
 292                                        rerere_autoupdate
 293                                        ? "Staged" : "Resolved",
 294                                        path);
 295                                goto mark_resolved;
 296                        }
 297                }
 298
 299                /* Let's see if we have resolved it. */
 300                ret = handle_file(path, NULL, NULL);
 301                if (ret)
 302                        continue;
 303
 304                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 305                copy_file(rr_path(name, "postimage"), path, 0666);
 306        mark_resolved:
 307                rr->items[i].util = NULL;
 308        }
 309
 310        if (update.nr)
 311                update_paths(&update);
 312
 313        return write_rr(rr, fd);
 314}
 315
 316static int git_rerere_config(const char *var, const char *value, void *cb)
 317{
 318        if (!strcmp(var, "rerere.enabled"))
 319                rerere_enabled = git_config_bool(var, value);
 320        else if (!strcmp(var, "rerere.autoupdate"))
 321                rerere_autoupdate = git_config_bool(var, value);
 322        else
 323                return git_default_config(var, value, cb);
 324        return 0;
 325}
 326
 327static int is_rerere_enabled(void)
 328{
 329        const char *rr_cache;
 330        int rr_cache_exists;
 331
 332        if (!rerere_enabled)
 333                return 0;
 334
 335        rr_cache = git_path("rr-cache");
 336        rr_cache_exists = is_directory(rr_cache);
 337        if (rerere_enabled < 0)
 338                return rr_cache_exists;
 339
 340        if (!rr_cache_exists &&
 341            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 342                die("Could not create directory %s", rr_cache);
 343        return 1;
 344}
 345
 346int setup_rerere(struct string_list *merge_rr)
 347{
 348        int fd;
 349
 350        git_config(git_rerere_config, NULL);
 351        if (!is_rerere_enabled())
 352                return -1;
 353
 354        merge_rr_path = xstrdup(git_path("MERGE_RR"));
 355        fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
 356                                       LOCK_DIE_ON_ERROR);
 357        read_rr(merge_rr);
 358        return fd;
 359}
 360
 361int rerere(void)
 362{
 363        struct string_list merge_rr = { NULL, 0, 0, 1 };
 364        int fd;
 365
 366        fd = setup_rerere(&merge_rr);
 367        if (fd < 0)
 368                return 0;
 369        return do_plain_rerere(&merge_rr, fd);
 370}