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, two;
  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        strbuf_init(&one, 0);
 101        strbuf_init(&two,  0);
 102        while (fgets(buf, sizeof(buf), f)) {
 103                if (!prefixcmp(buf, "<<<<<<< ")) {
 104                        if (hunk != RR_CONTEXT)
 105                                goto bad;
 106                        hunk = RR_SIDE_1;
 107                } else if (!prefixcmp(buf, "|||||||") && isspace(buf[7])) {
 108                        if (hunk != RR_SIDE_1)
 109                                goto bad;
 110                        hunk = RR_ORIGINAL;
 111                } else if (!prefixcmp(buf, "=======") && isspace(buf[7])) {
 112                        if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
 113                                goto bad;
 114                        hunk = RR_SIDE_2;
 115                } else if (!prefixcmp(buf, ">>>>>>> ")) {
 116                        if (hunk != RR_SIDE_2)
 117                                goto bad;
 118                        if (strbuf_cmp(&one, &two) > 0)
 119                                strbuf_swap(&one, &two);
 120                        hunk_no++;
 121                        hunk = RR_CONTEXT;
 122                        if (out) {
 123                                fputs("<<<<<<<\n", out);
 124                                fwrite(one.buf, one.len, 1, out);
 125                                fputs("=======\n", out);
 126                                fwrite(two.buf, two.len, 1, out);
 127                                fputs(">>>>>>>\n", out);
 128                        }
 129                        if (sha1) {
 130                                git_SHA1_Update(&ctx, one.buf ? one.buf : "",
 131                                            one.len + 1);
 132                                git_SHA1_Update(&ctx, two.buf ? two.buf : "",
 133                                            two.len + 1);
 134                        }
 135                        strbuf_reset(&one);
 136                        strbuf_reset(&two);
 137                } else if (hunk == RR_SIDE_1)
 138                        strbuf_addstr(&one, buf);
 139                else if (hunk == RR_ORIGINAL)
 140                        ; /* discard */
 141                else if (hunk == RR_SIDE_2)
 142                        strbuf_addstr(&two, buf);
 143                else if (out)
 144                        fputs(buf, out);
 145                continue;
 146        bad:
 147                hunk = 99; /* force error exit */
 148                break;
 149        }
 150        strbuf_release(&one);
 151        strbuf_release(&two);
 152
 153        fclose(f);
 154        if (out)
 155                fclose(out);
 156        if (sha1)
 157                git_SHA1_Final(sha1, &ctx);
 158        if (hunk != RR_CONTEXT) {
 159                if (output)
 160                        unlink(output);
 161                return error("Could not parse conflict hunks in %s", path);
 162        }
 163        return hunk_no;
 164}
 165
 166static int find_conflict(struct string_list *conflict)
 167{
 168        int i;
 169        if (read_cache() < 0)
 170                return error("Could not read index");
 171        for (i = 0; i+1 < active_nr; i++) {
 172                struct cache_entry *e2 = active_cache[i];
 173                struct cache_entry *e3 = active_cache[i+1];
 174                if (ce_stage(e2) == 2 &&
 175                    ce_stage(e3) == 3 &&
 176                    ce_same_name(e2, e3) &&
 177                    S_ISREG(e2->ce_mode) &&
 178                    S_ISREG(e3->ce_mode)) {
 179                        string_list_insert((const char *)e2->name, conflict);
 180                        i++; /* skip over both #2 and #3 */
 181                }
 182        }
 183        return 0;
 184}
 185
 186static int merge(const char *name, const char *path)
 187{
 188        int ret;
 189        mmfile_t cur, base, other;
 190        mmbuffer_t result = {NULL, 0};
 191        xpparam_t xpp = {XDF_NEED_MINIMAL};
 192
 193        if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 194                return 1;
 195
 196        if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 197                        read_mmfile(&base, rr_path(name, "preimage")) ||
 198                        read_mmfile(&other, rr_path(name, "postimage")))
 199                return 1;
 200        ret = xdl_merge(&base, &cur, "", &other, "",
 201                        &xpp, XDL_MERGE_ZEALOUS, &result);
 202        if (!ret) {
 203                FILE *f = fopen(path, "w");
 204                if (!f)
 205                        return error("Could not write to %s", path);
 206                fwrite(result.ptr, result.size, 1, f);
 207                fclose(f);
 208        }
 209
 210        free(cur.ptr);
 211        free(base.ptr);
 212        free(other.ptr);
 213        free(result.ptr);
 214
 215        return ret;
 216}
 217
 218static struct lock_file index_lock;
 219
 220static int update_paths(struct string_list *update)
 221{
 222        int i;
 223        int fd = hold_locked_index(&index_lock, 0);
 224        int status = 0;
 225
 226        if (fd < 0)
 227                return -1;
 228
 229        for (i = 0; i < update->nr; i++) {
 230                struct string_list_item *item = &update->items[i];
 231                if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
 232                        status = -1;
 233        }
 234
 235        if (!status && active_cache_changed) {
 236                if (write_cache(fd, active_cache, active_nr) ||
 237                    commit_locked_index(&index_lock))
 238                        die("Unable to write new index file");
 239        } else if (fd >= 0)
 240                rollback_lock_file(&index_lock);
 241        return status;
 242}
 243
 244static int do_plain_rerere(struct string_list *rr, int fd)
 245{
 246        struct string_list conflict = { NULL, 0, 0, 1 };
 247        struct string_list update = { NULL, 0, 0, 1 };
 248        int i;
 249
 250        find_conflict(&conflict);
 251
 252        /*
 253         * MERGE_RR records paths with conflicts immediately after merge
 254         * failed.  Some of the conflicted paths might have been hand resolved
 255         * in the working tree since then, but the initial run would catch all
 256         * and register their preimages.
 257         */
 258
 259        for (i = 0; i < conflict.nr; i++) {
 260                const char *path = conflict.items[i].string;
 261                if (!string_list_has_string(rr, path)) {
 262                        unsigned char sha1[20];
 263                        char *hex;
 264                        int ret;
 265                        ret = handle_file(path, sha1, NULL);
 266                        if (ret < 1)
 267                                continue;
 268                        hex = xstrdup(sha1_to_hex(sha1));
 269                        string_list_insert(path, rr)->util = hex;
 270                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 271                                continue;;
 272                        handle_file(path, NULL, rr_path(hex, "preimage"));
 273                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 274                }
 275        }
 276
 277        /*
 278         * Now some of the paths that had conflicts earlier might have been
 279         * hand resolved.  Others may be similar to a conflict already that
 280         * was resolved before.
 281         */
 282
 283        for (i = 0; i < rr->nr; i++) {
 284                int ret;
 285                const char *path = rr->items[i].string;
 286                const char *name = (const char *)rr->items[i].util;
 287
 288                if (has_resolution(name)) {
 289                        if (!merge(name, path)) {
 290                                if (rerere_autoupdate)
 291                                        string_list_insert(path, &update);
 292                                fprintf(stderr,
 293                                        "%s '%s' using previous resolution.\n",
 294                                        rerere_autoupdate
 295                                        ? "Staged" : "Resolved",
 296                                        path);
 297                                goto mark_resolved;
 298                        }
 299                }
 300
 301                /* Let's see if we have resolved it. */
 302                ret = handle_file(path, NULL, NULL);
 303                if (ret)
 304                        continue;
 305
 306                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 307                copy_file(rr_path(name, "postimage"), path, 0666);
 308        mark_resolved:
 309                rr->items[i].util = NULL;
 310        }
 311
 312        if (update.nr)
 313                update_paths(&update);
 314
 315        return write_rr(rr, fd);
 316}
 317
 318static int git_rerere_config(const char *var, const char *value, void *cb)
 319{
 320        if (!strcmp(var, "rerere.enabled"))
 321                rerere_enabled = git_config_bool(var, value);
 322        else if (!strcmp(var, "rerere.autoupdate"))
 323                rerere_autoupdate = git_config_bool(var, value);
 324        else
 325                return git_default_config(var, value, cb);
 326        return 0;
 327}
 328
 329static int is_rerere_enabled(void)
 330{
 331        const char *rr_cache;
 332        int rr_cache_exists;
 333
 334        if (!rerere_enabled)
 335                return 0;
 336
 337        rr_cache = git_path("rr-cache");
 338        rr_cache_exists = is_directory(rr_cache);
 339        if (rerere_enabled < 0)
 340                return rr_cache_exists;
 341
 342        if (!rr_cache_exists &&
 343            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 344                die("Could not create directory %s", rr_cache);
 345        return 1;
 346}
 347
 348int setup_rerere(struct string_list *merge_rr)
 349{
 350        int fd;
 351
 352        git_config(git_rerere_config, NULL);
 353        if (!is_rerere_enabled())
 354                return -1;
 355
 356        merge_rr_path = xstrdup(git_path("MERGE_RR"));
 357        fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
 358        read_rr(merge_rr);
 359        return fd;
 360}
 361
 362int rerere(void)
 363{
 364        struct string_list merge_rr = { NULL, 0, 0, 1 };
 365        int fd;
 366
 367        fd = setup_rerere(&merge_rr);
 368        if (fd < 0)
 369                return 0;
 370        return do_plain_rerere(&merge_rr, fd);
 371}