Andrew's git / gitweb.git / rerere.c
?
rerere.con commit diff --quiet: make it synonym to --exit-code >/dev/null (df58a82)
   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        SHA_CTX ctx;
  77        char buf[1024];
  78        int hunk = 0, hunk_no = 0;
  79        struct strbuf one, two;
  80        FILE *f = fopen(path, "r");
  81        FILE *out = NULL;
  82
  83        if (!f)
  84                return error("Could not open %s", path);
  85
  86        if (output) {
  87                out = fopen(output, "w");
  88                if (!out) {
  89                        fclose(f);
  90                        return error("Could not write %s", output);
  91                }
  92        }
  93
  94        if (sha1)
  95                SHA1_Init(&ctx);
  96
  97        strbuf_init(&one, 0);
  98        strbuf_init(&two,  0);
  99        while (fgets(buf, sizeof(buf), f)) {
 100                if (!prefixcmp(buf, "<<<<<<< ")) {
 101                        if (hunk)
 102                                goto bad;
 103                        hunk = 1;
 104                } else if (!prefixcmp(buf, "=======") && isspace(buf[7])) {
 105                        if (hunk != 1)
 106                                goto bad;
 107                        hunk = 2;
 108                } else if (!prefixcmp(buf, ">>>>>>> ")) {
 109                        if (hunk != 2)
 110                                goto bad;
 111                        if (strbuf_cmp(&one, &two) > 0)
 112                                strbuf_swap(&one, &two);
 113                        hunk_no++;
 114                        hunk = 0;
 115                        if (out) {
 116                                fputs("<<<<<<<\n", out);
 117                                fwrite(one.buf, one.len, 1, out);
 118                                fputs("=======\n", out);
 119                                fwrite(two.buf, two.len, 1, out);
 120                                fputs(">>>>>>>\n", out);
 121                        }
 122                        if (sha1) {
 123                                SHA1_Update(&ctx, one.buf ? one.buf : "",
 124                                            one.len + 1);
 125                                SHA1_Update(&ctx, two.buf ? two.buf : "",
 126                                            two.len + 1);
 127                        }
 128                        strbuf_reset(&one);
 129                        strbuf_reset(&two);
 130                } else if (hunk == 1)
 131                        strbuf_addstr(&one, buf);
 132                else if (hunk == 2)
 133                        strbuf_addstr(&two, buf);
 134                else if (out)
 135                        fputs(buf, out);
 136                continue;
 137        bad:
 138                hunk = 99; /* force error exit */
 139                break;
 140        }
 141        strbuf_release(&one);
 142        strbuf_release(&two);
 143
 144        fclose(f);
 145        if (out)
 146                fclose(out);
 147        if (sha1)
 148                SHA1_Final(sha1, &ctx);
 149        if (hunk) {
 150                if (output)
 151                        unlink(output);
 152                return error("Could not parse conflict hunks in %s", path);
 153        }
 154        return hunk_no;
 155}
 156
 157static int find_conflict(struct string_list *conflict)
 158{
 159        int i;
 160        if (read_cache() < 0)
 161                return error("Could not read index");
 162        for (i = 0; i+1 < active_nr; i++) {
 163                struct cache_entry *e2 = active_cache[i];
 164                struct cache_entry *e3 = active_cache[i+1];
 165                if (ce_stage(e2) == 2 &&
 166                    ce_stage(e3) == 3 &&
 167                    ce_same_name(e2, e3) &&
 168                    S_ISREG(e2->ce_mode) &&
 169                    S_ISREG(e3->ce_mode)) {
 170                        string_list_insert((const char *)e2->name, conflict);
 171                        i++; /* skip over both #2 and #3 */
 172                }
 173        }
 174        return 0;
 175}
 176
 177static int merge(const char *name, const char *path)
 178{
 179        int ret;
 180        mmfile_t cur, base, other;
 181        mmbuffer_t result = {NULL, 0};
 182        xpparam_t xpp = {XDF_NEED_MINIMAL};
 183
 184        if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 185                return 1;
 186
 187        if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 188                        read_mmfile(&base, rr_path(name, "preimage")) ||
 189                        read_mmfile(&other, rr_path(name, "postimage")))
 190                return 1;
 191        ret = xdl_merge(&base, &cur, "", &other, "",
 192                        &xpp, XDL_MERGE_ZEALOUS, &result);
 193        if (!ret) {
 194                FILE *f = fopen(path, "w");
 195                if (!f)
 196                        return error("Could not write to %s", path);
 197                fwrite(result.ptr, result.size, 1, f);
 198                fclose(f);
 199        }
 200
 201        free(cur.ptr);
 202        free(base.ptr);
 203        free(other.ptr);
 204        free(result.ptr);
 205
 206        return ret;
 207}
 208
 209static struct lock_file index_lock;
 210
 211static int update_paths(struct string_list *update)
 212{
 213        int i;
 214        int fd = hold_locked_index(&index_lock, 0);
 215        int status = 0;
 216
 217        if (fd < 0)
 218                return -1;
 219
 220        for (i = 0; i < update->nr; i++) {
 221                struct string_list_item *item = &update->items[i];
 222                if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
 223                        status = -1;
 224        }
 225
 226        if (!status && active_cache_changed) {
 227                if (write_cache(fd, active_cache, active_nr) ||
 228                    commit_locked_index(&index_lock))
 229                        die("Unable to write new index file");
 230        } else if (fd >= 0)
 231                rollback_lock_file(&index_lock);
 232        return status;
 233}
 234
 235static int do_plain_rerere(struct string_list *rr, int fd)
 236{
 237        struct string_list conflict = { NULL, 0, 0, 1 };
 238        struct string_list update = { NULL, 0, 0, 1 };
 239        int i;
 240
 241        find_conflict(&conflict);
 242
 243        /*
 244         * MERGE_RR records paths with conflicts immediately after merge
 245         * failed.  Some of the conflicted paths might have been hand resolved
 246         * in the working tree since then, but the initial run would catch all
 247         * and register their preimages.
 248         */
 249
 250        for (i = 0; i < conflict.nr; i++) {
 251                const char *path = conflict.items[i].string;
 252                if (!string_list_has_string(rr, path)) {
 253                        unsigned char sha1[20];
 254                        char *hex;
 255                        int ret;
 256                        ret = handle_file(path, sha1, NULL);
 257                        if (ret < 1)
 258                                continue;
 259                        hex = xstrdup(sha1_to_hex(sha1));
 260                        string_list_insert(path, rr)->util = hex;
 261                        if (mkdir(git_path("rr-cache/%s", hex), 0755))
 262                                continue;;
 263                        handle_file(path, NULL, rr_path(hex, "preimage"));
 264                        fprintf(stderr, "Recorded preimage for '%s'\n", path);
 265                }
 266        }
 267
 268        /*
 269         * Now some of the paths that had conflicts earlier might have been
 270         * hand resolved.  Others may be similar to a conflict already that
 271         * was resolved before.
 272         */
 273
 274        for (i = 0; i < rr->nr; i++) {
 275                int ret;
 276                const char *path = rr->items[i].string;
 277                const char *name = (const char *)rr->items[i].util;
 278
 279                if (has_resolution(name)) {
 280                        if (!merge(name, path)) {
 281                                if (rerere_autoupdate)
 282                                        string_list_insert(path, &update);
 283                                fprintf(stderr,
 284                                        "%s '%s' using previous resolution.\n",
 285                                        rerere_autoupdate
 286                                        ? "Staged" : "Resolved",
 287                                        path);
 288                                goto mark_resolved;
 289                        }
 290                }
 291
 292                /* Let's see if we have resolved it. */
 293                ret = handle_file(path, NULL, NULL);
 294                if (ret)
 295                        continue;
 296
 297                fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 298                copy_file(rr_path(name, "postimage"), path, 0666);
 299        mark_resolved:
 300                rr->items[i].util = NULL;
 301        }
 302
 303        if (update.nr)
 304                update_paths(&update);
 305
 306        return write_rr(rr, fd);
 307}
 308
 309static int git_rerere_config(const char *var, const char *value, void *cb)
 310{
 311        if (!strcmp(var, "rerere.enabled"))
 312                rerere_enabled = git_config_bool(var, value);
 313        else if (!strcmp(var, "rerere.autoupdate"))
 314                rerere_autoupdate = git_config_bool(var, value);
 315        else
 316                return git_default_config(var, value, cb);
 317        return 0;
 318}
 319
 320static int is_rerere_enabled(void)
 321{
 322        struct stat st;
 323        const char *rr_cache;
 324        int rr_cache_exists;
 325
 326        if (!rerere_enabled)
 327                return 0;
 328
 329        rr_cache = git_path("rr-cache");
 330        rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
 331        if (rerere_enabled < 0)
 332                return rr_cache_exists;
 333
 334        if (!rr_cache_exists &&
 335            (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
 336                die("Could not create directory %s", rr_cache);
 337        return 1;
 338}
 339
 340int setup_rerere(struct string_list *merge_rr)
 341{
 342        int fd;
 343
 344        git_config(git_rerere_config, NULL);
 345        if (!is_rerere_enabled())
 346                return -1;
 347
 348        merge_rr_path = xstrdup(git_path("MERGE_RR"));
 349        fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
 350        read_rr(merge_rr);
 351        return fd;
 352}
 353
 354int rerere(void)
 355{
 356        struct string_list merge_rr = { NULL, 0, 0, 1 };
 357        int fd;
 358
 359        fd = setup_rerere(&merge_rr);
 360        if (fd < 0)
 361                return 0;
 362        return do_plain_rerere(&merge_rr, fd);
 363}