refs.con commit Merge branch 'maint' (91527e5)
   1#include "cache.h"
   2#include "refs.h"
   3#include "object.h"
   4#include "tag.h"
   5#include "dir.h"
   6
   7/* ISSYMREF=0x01, ISPACKED=0x02 and ISBROKEN=0x04 are public interfaces */
   8#define REF_KNOWS_PEELED 0x10
   9
  10struct ref_entry {
  11        unsigned char flag; /* ISSYMREF? ISPACKED? */
  12        unsigned char sha1[20];
  13        unsigned char peeled[20];
  14        /* The full name of the reference (e.g., "refs/heads/master"): */
  15        char name[FLEX_ARRAY];
  16};
  17
  18struct ref_array {
  19        int nr, alloc;
  20
  21        /*
  22         * Entries with index 0 <= i < sorted are sorted by name.  New
  23         * entries are appended to the list unsorted, and are sorted
  24         * only when required; thus we avoid the need to sort the list
  25         * after the addition of every reference.
  26         */
  27        int sorted;
  28
  29        struct ref_entry **refs;
  30};
  31
  32/*
  33 * Parse one line from a packed-refs file.  Write the SHA1 to sha1.
  34 * Return a pointer to the refname within the line (null-terminated),
  35 * or NULL if there was a problem.
  36 */
  37static const char *parse_ref_line(char *line, unsigned char *sha1)
  38{
  39        /*
  40         * 42: the answer to everything.
  41         *
  42         * In this case, it happens to be the answer to
  43         *  40 (length of sha1 hex representation)
  44         *  +1 (space in between hex and name)
  45         *  +1 (newline at the end of the line)
  46         */
  47        int len = strlen(line) - 42;
  48
  49        if (len <= 0)
  50                return NULL;
  51        if (get_sha1_hex(line, sha1) < 0)
  52                return NULL;
  53        if (!isspace(line[40]))
  54                return NULL;
  55        line += 41;
  56        if (isspace(*line))
  57                return NULL;
  58        if (line[len] != '\n')
  59                return NULL;
  60        line[len] = 0;
  61
  62        return line;
  63}
  64
  65static struct ref_entry *create_ref_entry(const char *refname,
  66                                          const unsigned char *sha1, int flag,
  67                                          int check_name)
  68{
  69        int len;
  70        struct ref_entry *ref;
  71
  72        if (check_name &&
  73            check_refname_format(refname, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
  74                die("Reference has invalid format: '%s'", refname);
  75        len = strlen(refname) + 1;
  76        ref = xmalloc(sizeof(struct ref_entry) + len);
  77        hashcpy(ref->sha1, sha1);
  78        hashclr(ref->peeled);
  79        memcpy(ref->name, refname, len);
  80        ref->flag = flag;
  81        return ref;
  82}
  83
  84/* Add a ref_entry to the end of the ref_array (unsorted). */
  85static void add_ref(struct ref_array *refs, struct ref_entry *ref)
  86{
  87        ALLOC_GROW(refs->refs, refs->nr + 1, refs->alloc);
  88        refs->refs[refs->nr++] = ref;
  89}
  90
  91static int ref_entry_cmp(const void *a, const void *b)
  92{
  93        struct ref_entry *one = *(struct ref_entry **)a;
  94        struct ref_entry *two = *(struct ref_entry **)b;
  95        return strcmp(one->name, two->name);
  96}
  97
  98/*
  99 * Emit a warning and return true iff ref1 and ref2 have the same name
 100 * and the same sha1.  Die if they have the same name but different
 101 * sha1s.
 102 */
 103static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
 104{
 105        if (!strcmp(ref1->name, ref2->name)) {
 106                /* Duplicate name; make sure that the SHA1s match: */
 107                if (hashcmp(ref1->sha1, ref2->sha1))
 108                        die("Duplicated ref, and SHA1s don't match: %s",
 109                            ref1->name);
 110                warning("Duplicated ref: %s", ref1->name);
 111                return 1;
 112        } else {
 113                return 0;
 114        }
 115}
 116
 117/*
 118 * Sort the entries in array (if they are not already sorted).
 119 */
 120static void sort_ref_array(struct ref_array *array)
 121{
 122        int i, j;
 123
 124        /*
 125         * This check also prevents passing a zero-length array to qsort(),
 126         * which is a problem on some platforms.
 127         */
 128        if (array->sorted == array->nr)
 129                return;
 130
 131        qsort(array->refs, array->nr, sizeof(*array->refs), ref_entry_cmp);
 132
 133        /* Remove any duplicates from the ref_array */
 134        i = 0;
 135        for (j = 1; j < array->nr; j++) {
 136                if (is_dup_ref(array->refs[i], array->refs[j])) {
 137                        free(array->refs[j]);
 138                        continue;
 139                }
 140                array->refs[++i] = array->refs[j];
 141        }
 142        array->sorted = array->nr = i + 1;
 143}
 144
 145static struct ref_entry *search_ref_array(struct ref_array *array, const char *refname)
 146{
 147        struct ref_entry *e, **r;
 148        int len;
 149
 150        if (refname == NULL)
 151                return NULL;
 152
 153        if (!array->nr)
 154                return NULL;
 155        sort_ref_array(array);
 156        len = strlen(refname) + 1;
 157        e = xmalloc(sizeof(struct ref_entry) + len);
 158        memcpy(e->name, refname, len);
 159
 160        r = bsearch(&e, array->refs, array->nr, sizeof(*array->refs), ref_entry_cmp);
 161
 162        free(e);
 163
 164        if (r == NULL)
 165                return NULL;
 166
 167        return *r;
 168}
 169
 170/*
 171 * Future: need to be in "struct repository"
 172 * when doing a full libification.
 173 */
 174static struct ref_cache {
 175        struct ref_cache *next;
 176        char did_loose;
 177        char did_packed;
 178        struct ref_array loose;
 179        struct ref_array packed;
 180        /* The submodule name, or "" for the main repo. */
 181        char name[FLEX_ARRAY];
 182} *ref_cache;
 183
 184static struct ref_entry *current_ref;
 185
 186static void clear_ref_array(struct ref_array *array)
 187{
 188        int i;
 189        for (i = 0; i < array->nr; i++)
 190                free(array->refs[i]);
 191        free(array->refs);
 192        array->sorted = array->nr = array->alloc = 0;
 193        array->refs = NULL;
 194}
 195
 196static void clear_packed_ref_cache(struct ref_cache *refs)
 197{
 198        if (refs->did_packed)
 199                clear_ref_array(&refs->packed);
 200        refs->did_packed = 0;
 201}
 202
 203static void clear_loose_ref_cache(struct ref_cache *refs)
 204{
 205        if (refs->did_loose)
 206                clear_ref_array(&refs->loose);
 207        refs->did_loose = 0;
 208}
 209
 210static struct ref_cache *create_ref_cache(const char *submodule)
 211{
 212        int len;
 213        struct ref_cache *refs;
 214        if (!submodule)
 215                submodule = "";
 216        len = strlen(submodule) + 1;
 217        refs = xcalloc(1, sizeof(struct ref_cache) + len);
 218        memcpy(refs->name, submodule, len);
 219        return refs;
 220}
 221
 222/*
 223 * Return a pointer to a ref_cache for the specified submodule. For
 224 * the main repository, use submodule==NULL. The returned structure
 225 * will be allocated and initialized but not necessarily populated; it
 226 * should not be freed.
 227 */
 228static struct ref_cache *get_ref_cache(const char *submodule)
 229{
 230        struct ref_cache *refs = ref_cache;
 231        if (!submodule)
 232                submodule = "";
 233        while (refs) {
 234                if (!strcmp(submodule, refs->name))
 235                        return refs;
 236                refs = refs->next;
 237        }
 238
 239        refs = create_ref_cache(submodule);
 240        refs->next = ref_cache;
 241        ref_cache = refs;
 242        return refs;
 243}
 244
 245void invalidate_ref_cache(const char *submodule)
 246{
 247        struct ref_cache *refs = get_ref_cache(submodule);
 248        clear_packed_ref_cache(refs);
 249        clear_loose_ref_cache(refs);
 250}
 251
 252static void read_packed_refs(FILE *f, struct ref_array *array)
 253{
 254        struct ref_entry *last = NULL;
 255        char refline[PATH_MAX];
 256        int flag = REF_ISPACKED;
 257
 258        while (fgets(refline, sizeof(refline), f)) {
 259                unsigned char sha1[20];
 260                const char *refname;
 261                static const char header[] = "# pack-refs with:";
 262
 263                if (!strncmp(refline, header, sizeof(header)-1)) {
 264                        const char *traits = refline + sizeof(header) - 1;
 265                        if (strstr(traits, " peeled "))
 266                                flag |= REF_KNOWS_PEELED;
 267                        /* perhaps other traits later as well */
 268                        continue;
 269                }
 270
 271                refname = parse_ref_line(refline, sha1);
 272                if (refname) {
 273                        last = create_ref_entry(refname, sha1, flag, 1);
 274                        add_ref(array, last);
 275                        continue;
 276                }
 277                if (last &&
 278                    refline[0] == '^' &&
 279                    strlen(refline) == 42 &&
 280                    refline[41] == '\n' &&
 281                    !get_sha1_hex(refline + 1, sha1))
 282                        hashcpy(last->peeled, sha1);
 283        }
 284}
 285
 286static struct ref_array *get_packed_refs(struct ref_cache *refs)
 287{
 288        if (!refs->did_packed) {
 289                const char *packed_refs_file;
 290                FILE *f;
 291
 292                if (*refs->name)
 293                        packed_refs_file = git_path_submodule(refs->name, "packed-refs");
 294                else
 295                        packed_refs_file = git_path("packed-refs");
 296                f = fopen(packed_refs_file, "r");
 297                if (f) {
 298                        read_packed_refs(f, &refs->packed);
 299                        fclose(f);
 300                }
 301                refs->did_packed = 1;
 302        }
 303        return &refs->packed;
 304}
 305
 306void add_packed_ref(const char *refname, const unsigned char *sha1)
 307{
 308        add_ref(get_packed_refs(get_ref_cache(NULL)),
 309                        create_ref_entry(refname, sha1, REF_ISPACKED, 1));
 310}
 311
 312static void get_ref_dir(struct ref_cache *refs, const char *base,
 313                        struct ref_array *array)
 314{
 315        DIR *dir;
 316        const char *path;
 317
 318        if (*refs->name)
 319                path = git_path_submodule(refs->name, "%s", base);
 320        else
 321                path = git_path("%s", base);
 322
 323
 324        dir = opendir(path);
 325
 326        if (dir) {
 327                struct dirent *de;
 328                int baselen = strlen(base);
 329                char *refname = xmalloc(baselen + 257);
 330
 331                memcpy(refname, base, baselen);
 332                if (baselen && base[baselen-1] != '/')
 333                        refname[baselen++] = '/';
 334
 335                while ((de = readdir(dir)) != NULL) {
 336                        unsigned char sha1[20];
 337                        struct stat st;
 338                        int flag;
 339                        int namelen;
 340                        const char *refdir;
 341
 342                        if (de->d_name[0] == '.')
 343                                continue;
 344                        namelen = strlen(de->d_name);
 345                        if (namelen > 255)
 346                                continue;
 347                        if (has_extension(de->d_name, ".lock"))
 348                                continue;
 349                        memcpy(refname + baselen, de->d_name, namelen+1);
 350                        refdir = *refs->name
 351                                ? git_path_submodule(refs->name, "%s", refname)
 352                                : git_path("%s", refname);
 353                        if (stat(refdir, &st) < 0)
 354                                continue;
 355                        if (S_ISDIR(st.st_mode)) {
 356                                get_ref_dir(refs, refname, array);
 357                                continue;
 358                        }
 359                        if (*refs->name) {
 360                                hashclr(sha1);
 361                                flag = 0;
 362                                if (resolve_gitlink_ref(refs->name, refname, sha1) < 0) {
 363                                        hashclr(sha1);
 364                                        flag |= REF_ISBROKEN;
 365                                }
 366                        } else if (read_ref_full(refname, sha1, 1, &flag)) {
 367                                hashclr(sha1);
 368                                flag |= REF_ISBROKEN;
 369                        }
 370                        add_ref(array, create_ref_entry(refname, sha1, flag, 1));
 371                }
 372                free(refname);
 373                closedir(dir);
 374        }
 375}
 376
 377struct warn_if_dangling_data {
 378        FILE *fp;
 379        const char *refname;
 380        const char *msg_fmt;
 381};
 382
 383static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
 384                                   int flags, void *cb_data)
 385{
 386        struct warn_if_dangling_data *d = cb_data;
 387        const char *resolves_to;
 388        unsigned char junk[20];
 389
 390        if (!(flags & REF_ISSYMREF))
 391                return 0;
 392
 393        resolves_to = resolve_ref_unsafe(refname, junk, 0, NULL);
 394        if (!resolves_to || strcmp(resolves_to, d->refname))
 395                return 0;
 396
 397        fprintf(d->fp, d->msg_fmt, refname);
 398        return 0;
 399}
 400
 401void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 402{
 403        struct warn_if_dangling_data data;
 404
 405        data.fp = fp;
 406        data.refname = refname;
 407        data.msg_fmt = msg_fmt;
 408        for_each_rawref(warn_if_dangling_symref, &data);
 409}
 410
 411static struct ref_array *get_loose_refs(struct ref_cache *refs)
 412{
 413        if (!refs->did_loose) {
 414                get_ref_dir(refs, "refs", &refs->loose);
 415                refs->did_loose = 1;
 416        }
 417        return &refs->loose;
 418}
 419
 420/* We allow "recursive" symbolic refs. Only within reason, though */
 421#define MAXDEPTH 5
 422#define MAXREFLEN (1024)
 423
 424/*
 425 * Called by resolve_gitlink_ref_recursive() after it failed to read
 426 * from the loose refs in ref_cache refs. Find <refname> in the
 427 * packed-refs file for the submodule.
 428 */
 429static int resolve_gitlink_packed_ref(struct ref_cache *refs,
 430                                      const char *refname, unsigned char *sha1)
 431{
 432        struct ref_entry *ref;
 433        struct ref_array *array = get_packed_refs(refs);
 434
 435        ref = search_ref_array(array, refname);
 436        if (ref == NULL)
 437                return -1;
 438
 439        memcpy(sha1, ref->sha1, 20);
 440        return 0;
 441}
 442
 443static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
 444                                         const char *refname, unsigned char *sha1,
 445                                         int recursion)
 446{
 447        int fd, len;
 448        char buffer[128], *p;
 449        char *path;
 450
 451        if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
 452                return -1;
 453        path = *refs->name
 454                ? git_path_submodule(refs->name, "%s", refname)
 455                : git_path("%s", refname);
 456        fd = open(path, O_RDONLY);
 457        if (fd < 0)
 458                return resolve_gitlink_packed_ref(refs, refname, sha1);
 459
 460        len = read(fd, buffer, sizeof(buffer)-1);
 461        close(fd);
 462        if (len < 0)
 463                return -1;
 464        while (len && isspace(buffer[len-1]))
 465                len--;
 466        buffer[len] = 0;
 467
 468        /* Was it a detached head or an old-fashioned symlink? */
 469        if (!get_sha1_hex(buffer, sha1))
 470                return 0;
 471
 472        /* Symref? */
 473        if (strncmp(buffer, "ref:", 4))
 474                return -1;
 475        p = buffer + 4;
 476        while (isspace(*p))
 477                p++;
 478
 479        return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
 480}
 481
 482int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
 483{
 484        int len = strlen(path), retval;
 485        char *submodule;
 486        struct ref_cache *refs;
 487
 488        while (len && path[len-1] == '/')
 489                len--;
 490        if (!len)
 491                return -1;
 492        submodule = xstrndup(path, len);
 493        refs = get_ref_cache(submodule);
 494        free(submodule);
 495
 496        retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
 497        return retval;
 498}
 499
 500/*
 501 * Try to read ref from the packed references.  On success, set sha1
 502 * and return 0; otherwise, return -1.
 503 */
 504static int get_packed_ref(const char *refname, unsigned char *sha1)
 505{
 506        struct ref_array *packed = get_packed_refs(get_ref_cache(NULL));
 507        struct ref_entry *entry = search_ref_array(packed, refname);
 508        if (entry) {
 509                hashcpy(sha1, entry->sha1);
 510                return 0;
 511        }
 512        return -1;
 513}
 514
 515const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int reading, int *flag)
 516{
 517        int depth = MAXDEPTH;
 518        ssize_t len;
 519        char buffer[256];
 520        static char refname_buffer[256];
 521
 522        if (flag)
 523                *flag = 0;
 524
 525        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
 526                return NULL;
 527
 528        for (;;) {
 529                char path[PATH_MAX];
 530                struct stat st;
 531                char *buf;
 532                int fd;
 533
 534                if (--depth < 0)
 535                        return NULL;
 536
 537                git_snpath(path, sizeof(path), "%s", refname);
 538
 539                if (lstat(path, &st) < 0) {
 540                        if (errno != ENOENT)
 541                                return NULL;
 542                        /*
 543                         * The loose reference file does not exist;
 544                         * check for a packed reference.
 545                         */
 546                        if (!get_packed_ref(refname, sha1)) {
 547                                if (flag)
 548                                        *flag |= REF_ISPACKED;
 549                                return refname;
 550                        }
 551                        /* The reference is not a packed reference, either. */
 552                        if (reading) {
 553                                return NULL;
 554                        } else {
 555                                hashclr(sha1);
 556                                return refname;
 557                        }
 558                }
 559
 560                /* Follow "normalized" - ie "refs/.." symlinks by hand */
 561                if (S_ISLNK(st.st_mode)) {
 562                        len = readlink(path, buffer, sizeof(buffer)-1);
 563                        if (len < 0)
 564                                return NULL;
 565                        buffer[len] = 0;
 566                        if (!prefixcmp(buffer, "refs/") &&
 567                                        !check_refname_format(buffer, 0)) {
 568                                strcpy(refname_buffer, buffer);
 569                                refname = refname_buffer;
 570                                if (flag)
 571                                        *flag |= REF_ISSYMREF;
 572                                continue;
 573                        }
 574                }
 575
 576                /* Is it a directory? */
 577                if (S_ISDIR(st.st_mode)) {
 578                        errno = EISDIR;
 579                        return NULL;
 580                }
 581
 582                /*
 583                 * Anything else, just open it and try to use it as
 584                 * a ref
 585                 */
 586                fd = open(path, O_RDONLY);
 587                if (fd < 0)
 588                        return NULL;
 589                len = read_in_full(fd, buffer, sizeof(buffer)-1);
 590                close(fd);
 591                if (len < 0)
 592                        return NULL;
 593                while (len && isspace(buffer[len-1]))
 594                        len--;
 595                buffer[len] = '\0';
 596
 597                /*
 598                 * Is it a symbolic ref?
 599                 */
 600                if (prefixcmp(buffer, "ref:"))
 601                        break;
 602                if (flag)
 603                        *flag |= REF_ISSYMREF;
 604                buf = buffer + 4;
 605                while (isspace(*buf))
 606                        buf++;
 607                if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
 608                        if (flag)
 609                                *flag |= REF_ISBROKEN;
 610                        return NULL;
 611                }
 612                refname = strcpy(refname_buffer, buf);
 613        }
 614        /* Please note that FETCH_HEAD has a second line containing other data. */
 615        if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
 616                if (flag)
 617                        *flag |= REF_ISBROKEN;
 618                return NULL;
 619        }
 620        return refname;
 621}
 622
 623char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, int *flag)
 624{
 625        const char *ret = resolve_ref_unsafe(ref, sha1, reading, flag);
 626        return ret ? xstrdup(ret) : NULL;
 627}
 628
 629/* The argument to filter_refs */
 630struct ref_filter {
 631        const char *pattern;
 632        each_ref_fn *fn;
 633        void *cb_data;
 634};
 635
 636int read_ref_full(const char *refname, unsigned char *sha1, int reading, int *flags)
 637{
 638        if (resolve_ref_unsafe(refname, sha1, reading, flags))
 639                return 0;
 640        return -1;
 641}
 642
 643int read_ref(const char *refname, unsigned char *sha1)
 644{
 645        return read_ref_full(refname, sha1, 1, NULL);
 646}
 647
 648#define DO_FOR_EACH_INCLUDE_BROKEN 01
 649static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 650                      int flags, void *cb_data, struct ref_entry *entry)
 651{
 652        if (prefixcmp(entry->name, base))
 653                return 0;
 654
 655        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 656                if (entry->flag & REF_ISBROKEN)
 657                        return 0; /* ignore broken refs e.g. dangling symref */
 658                if (!has_sha1_file(entry->sha1)) {
 659                        error("%s does not point to a valid object!", entry->name);
 660                        return 0;
 661                }
 662        }
 663        current_ref = entry;
 664        return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
 665}
 666
 667static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
 668                       void *data)
 669{
 670        struct ref_filter *filter = (struct ref_filter *)data;
 671        if (fnmatch(filter->pattern, refname, 0))
 672                return 0;
 673        return filter->fn(refname, sha1, flags, filter->cb_data);
 674}
 675
 676int peel_ref(const char *refname, unsigned char *sha1)
 677{
 678        int flag;
 679        unsigned char base[20];
 680        struct object *o;
 681
 682        if (current_ref && (current_ref->name == refname
 683                || !strcmp(current_ref->name, refname))) {
 684                if (current_ref->flag & REF_KNOWS_PEELED) {
 685                        hashcpy(sha1, current_ref->peeled);
 686                        return 0;
 687                }
 688                hashcpy(base, current_ref->sha1);
 689                goto fallback;
 690        }
 691
 692        if (read_ref_full(refname, base, 1, &flag))
 693                return -1;
 694
 695        if ((flag & REF_ISPACKED)) {
 696                struct ref_array *array = get_packed_refs(get_ref_cache(NULL));
 697                struct ref_entry *r = search_ref_array(array, refname);
 698
 699                if (r != NULL && r->flag & REF_KNOWS_PEELED) {
 700                        hashcpy(sha1, r->peeled);
 701                        return 0;
 702                }
 703        }
 704
 705fallback:
 706        o = parse_object(base);
 707        if (o && o->type == OBJ_TAG) {
 708                o = deref_tag(o, refname, 0);
 709                if (o) {
 710                        hashcpy(sha1, o->sha1);
 711                        return 0;
 712                }
 713        }
 714        return -1;
 715}
 716
 717static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
 718                           int trim, int flags, void *cb_data)
 719{
 720        int retval = 0, p = 0, l = 0;
 721        struct ref_cache *refs = get_ref_cache(submodule);
 722        struct ref_array *packed = get_packed_refs(refs);
 723        struct ref_array *loose = get_loose_refs(refs);
 724
 725        sort_ref_array(packed);
 726        sort_ref_array(loose);
 727        while (p < packed->nr && l < loose->nr) {
 728                struct ref_entry *entry;
 729                int cmp = strcmp(packed->refs[p]->name, loose->refs[l]->name);
 730                if (!cmp) {
 731                        p++;
 732                        continue;
 733                }
 734                if (cmp > 0) {
 735                        entry = loose->refs[l++];
 736                } else {
 737                        entry = packed->refs[p++];
 738                }
 739                retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 740                if (retval)
 741                        goto end_each;
 742        }
 743
 744        if (l < loose->nr) {
 745                p = l;
 746                packed = loose;
 747        }
 748
 749        for (; p < packed->nr; p++) {
 750                retval = do_one_ref(base, fn, trim, flags, cb_data, packed->refs[p]);
 751                if (retval)
 752                        goto end_each;
 753        }
 754
 755end_each:
 756        current_ref = NULL;
 757        return retval;
 758}
 759
 760
 761static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
 762{
 763        unsigned char sha1[20];
 764        int flag;
 765
 766        if (submodule) {
 767                if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
 768                        return fn("HEAD", sha1, 0, cb_data);
 769
 770                return 0;
 771        }
 772
 773        if (!read_ref_full("HEAD", sha1, 1, &flag))
 774                return fn("HEAD", sha1, flag, cb_data);
 775
 776        return 0;
 777}
 778
 779int head_ref(each_ref_fn fn, void *cb_data)
 780{
 781        return do_head_ref(NULL, fn, cb_data);
 782}
 783
 784int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 785{
 786        return do_head_ref(submodule, fn, cb_data);
 787}
 788
 789int for_each_ref(each_ref_fn fn, void *cb_data)
 790{
 791        return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
 792}
 793
 794int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 795{
 796        return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
 797}
 798
 799int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 800{
 801        return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
 802}
 803
 804int for_each_ref_in_submodule(const char *submodule, const char *prefix,
 805                each_ref_fn fn, void *cb_data)
 806{
 807        return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
 808}
 809
 810int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 811{
 812        return for_each_ref_in("refs/tags/", fn, cb_data);
 813}
 814
 815int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 816{
 817        return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
 818}
 819
 820int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 821{
 822        return for_each_ref_in("refs/heads/", fn, cb_data);
 823}
 824
 825int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 826{
 827        return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
 828}
 829
 830int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 831{
 832        return for_each_ref_in("refs/remotes/", fn, cb_data);
 833}
 834
 835int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 836{
 837        return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
 838}
 839
 840int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 841{
 842        return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
 843}
 844
 845int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 846{
 847        struct strbuf buf = STRBUF_INIT;
 848        int ret = 0;
 849        unsigned char sha1[20];
 850        int flag;
 851
 852        strbuf_addf(&buf, "%sHEAD", get_git_namespace());
 853        if (!read_ref_full(buf.buf, sha1, 1, &flag))
 854                ret = fn(buf.buf, sha1, flag, cb_data);
 855        strbuf_release(&buf);
 856
 857        return ret;
 858}
 859
 860int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
 861{
 862        struct strbuf buf = STRBUF_INIT;
 863        int ret;
 864        strbuf_addf(&buf, "%srefs/", get_git_namespace());
 865        ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
 866        strbuf_release(&buf);
 867        return ret;
 868}
 869
 870int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 871        const char *prefix, void *cb_data)
 872{
 873        struct strbuf real_pattern = STRBUF_INIT;
 874        struct ref_filter filter;
 875        int ret;
 876
 877        if (!prefix && prefixcmp(pattern, "refs/"))
 878                strbuf_addstr(&real_pattern, "refs/");
 879        else if (prefix)
 880                strbuf_addstr(&real_pattern, prefix);
 881        strbuf_addstr(&real_pattern, pattern);
 882
 883        if (!has_glob_specials(pattern)) {
 884                /* Append implied '/' '*' if not present. */
 885                if (real_pattern.buf[real_pattern.len - 1] != '/')
 886                        strbuf_addch(&real_pattern, '/');
 887                /* No need to check for '*', there is none. */
 888                strbuf_addch(&real_pattern, '*');
 889        }
 890
 891        filter.pattern = real_pattern.buf;
 892        filter.fn = fn;
 893        filter.cb_data = cb_data;
 894        ret = for_each_ref(filter_refs, &filter);
 895
 896        strbuf_release(&real_pattern);
 897        return ret;
 898}
 899
 900int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 901{
 902        return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
 903}
 904
 905int for_each_rawref(each_ref_fn fn, void *cb_data)
 906{
 907        return do_for_each_ref(NULL, "", fn, 0,
 908                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 909}
 910
 911/*
 912 * Make sure "ref" is something reasonable to have under ".git/refs/";
 913 * We do not like it if:
 914 *
 915 * - any path component of it begins with ".", or
 916 * - it has double dots "..", or
 917 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
 918 * - it ends with a "/".
 919 * - it ends with ".lock"
 920 * - it contains a "\" (backslash)
 921 */
 922
 923/* Return true iff ch is not allowed in reference names. */
 924static inline int bad_ref_char(int ch)
 925{
 926        if (((unsigned) ch) <= ' ' || ch == 0x7f ||
 927            ch == '~' || ch == '^' || ch == ':' || ch == '\\')
 928                return 1;
 929        /* 2.13 Pattern Matching Notation */
 930        if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
 931                return 1;
 932        return 0;
 933}
 934
 935/*
 936 * Try to read one refname component from the front of refname.  Return
 937 * the length of the component found, or -1 if the component is not
 938 * legal.
 939 */
 940static int check_refname_component(const char *refname, int flags)
 941{
 942        const char *cp;
 943        char last = '\0';
 944
 945        for (cp = refname; ; cp++) {
 946                char ch = *cp;
 947                if (ch == '\0' || ch == '/')
 948                        break;
 949                if (bad_ref_char(ch))
 950                        return -1; /* Illegal character in refname. */
 951                if (last == '.' && ch == '.')
 952                        return -1; /* Refname contains "..". */
 953                if (last == '@' && ch == '{')
 954                        return -1; /* Refname contains "@{". */
 955                last = ch;
 956        }
 957        if (cp == refname)
 958                return -1; /* Component has zero length. */
 959        if (refname[0] == '.') {
 960                if (!(flags & REFNAME_DOT_COMPONENT))
 961                        return -1; /* Component starts with '.'. */
 962                /*
 963                 * Even if leading dots are allowed, don't allow "."
 964                 * as a component (".." is prevented by a rule above).
 965                 */
 966                if (refname[1] == '\0')
 967                        return -1; /* Component equals ".". */
 968        }
 969        if (cp - refname >= 5 && !memcmp(cp - 5, ".lock", 5))
 970                return -1; /* Refname ends with ".lock". */
 971        return cp - refname;
 972}
 973
 974int check_refname_format(const char *refname, int flags)
 975{
 976        int component_len, component_count = 0;
 977
 978        while (1) {
 979                /* We are at the start of a path component. */
 980                component_len = check_refname_component(refname, flags);
 981                if (component_len < 0) {
 982                        if ((flags & REFNAME_REFSPEC_PATTERN) &&
 983                                        refname[0] == '*' &&
 984                                        (refname[1] == '\0' || refname[1] == '/')) {
 985                                /* Accept one wildcard as a full refname component. */
 986                                flags &= ~REFNAME_REFSPEC_PATTERN;
 987                                component_len = 1;
 988                        } else {
 989                                return -1;
 990                        }
 991                }
 992                component_count++;
 993                if (refname[component_len] == '\0')
 994                        break;
 995                /* Skip to next component. */
 996                refname += component_len + 1;
 997        }
 998
 999        if (refname[component_len - 1] == '.')
1000                return -1; /* Refname ends with '.'. */
1001        if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
1002                return -1; /* Refname has only one component. */
1003        return 0;
1004}
1005
1006const char *prettify_refname(const char *name)
1007{
1008        return name + (
1009                !prefixcmp(name, "refs/heads/") ? 11 :
1010                !prefixcmp(name, "refs/tags/") ? 10 :
1011                !prefixcmp(name, "refs/remotes/") ? 13 :
1012                0);
1013}
1014
1015const char *ref_rev_parse_rules[] = {
1016        "%.*s",
1017        "refs/%.*s",
1018        "refs/tags/%.*s",
1019        "refs/heads/%.*s",
1020        "refs/remotes/%.*s",
1021        "refs/remotes/%.*s/HEAD",
1022        NULL
1023};
1024
1025int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
1026{
1027        const char **p;
1028        const int abbrev_name_len = strlen(abbrev_name);
1029
1030        for (p = rules; *p; p++) {
1031                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1032                        return 1;
1033                }
1034        }
1035
1036        return 0;
1037}
1038
1039static struct ref_lock *verify_lock(struct ref_lock *lock,
1040        const unsigned char *old_sha1, int mustexist)
1041{
1042        if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1043                error("Can't verify ref %s", lock->ref_name);
1044                unlock_ref(lock);
1045                return NULL;
1046        }
1047        if (hashcmp(lock->old_sha1, old_sha1)) {
1048                error("Ref %s is at %s but expected %s", lock->ref_name,
1049                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1050                unlock_ref(lock);
1051                return NULL;
1052        }
1053        return lock;
1054}
1055
1056static int remove_empty_directories(const char *file)
1057{
1058        /* we want to create a file but there is a directory there;
1059         * if that is an empty directory (or a directory that contains
1060         * only empty directories), remove them.
1061         */
1062        struct strbuf path;
1063        int result;
1064
1065        strbuf_init(&path, 20);
1066        strbuf_addstr(&path, file);
1067
1068        result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1069
1070        strbuf_release(&path);
1071
1072        return result;
1073}
1074
1075/*
1076 * Return true iff a reference named refname could be created without
1077 * conflicting with the name of an existing reference.  If oldrefname
1078 * is non-NULL, ignore potential conflicts with oldrefname (e.g.,
1079 * because oldrefname is scheduled for deletion in the same
1080 * operation).
1081 */
1082static int is_refname_available(const char *refname, const char *oldrefname,
1083                                struct ref_array *array)
1084{
1085        int i, namlen = strlen(refname); /* e.g. 'foo/bar' */
1086        for (i = 0; i < array->nr; i++ ) {
1087                struct ref_entry *entry = array->refs[i];
1088                /* entry->name could be 'foo' or 'foo/bar/baz' */
1089                if (!oldrefname || strcmp(oldrefname, entry->name)) {
1090                        int len = strlen(entry->name);
1091                        int cmplen = (namlen < len) ? namlen : len;
1092                        const char *lead = (namlen < len) ? entry->name : refname;
1093                        if (!strncmp(refname, entry->name, cmplen) &&
1094                            lead[cmplen] == '/') {
1095                                error("'%s' exists; cannot create '%s'",
1096                                      entry->name, refname);
1097                                return 0;
1098                        }
1099                }
1100        }
1101        return 1;
1102}
1103
1104/*
1105 * *string and *len will only be substituted, and *string returned (for
1106 * later free()ing) if the string passed in is a magic short-hand form
1107 * to name a branch.
1108 */
1109static char *substitute_branch_name(const char **string, int *len)
1110{
1111        struct strbuf buf = STRBUF_INIT;
1112        int ret = interpret_branch_name(*string, &buf);
1113
1114        if (ret == *len) {
1115                size_t size;
1116                *string = strbuf_detach(&buf, &size);
1117                *len = size;
1118                return (char *)*string;
1119        }
1120
1121        return NULL;
1122}
1123
1124int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
1125{
1126        char *last_branch = substitute_branch_name(&str, &len);
1127        const char **p, *r;
1128        int refs_found = 0;
1129
1130        *ref = NULL;
1131        for (p = ref_rev_parse_rules; *p; p++) {
1132                char fullref[PATH_MAX];
1133                unsigned char sha1_from_ref[20];
1134                unsigned char *this_result;
1135                int flag;
1136
1137                this_result = refs_found ? sha1_from_ref : sha1;
1138                mksnpath(fullref, sizeof(fullref), *p, len, str);
1139                r = resolve_ref_unsafe(fullref, this_result, 1, &flag);
1140                if (r) {
1141                        if (!refs_found++)
1142                                *ref = xstrdup(r);
1143                        if (!warn_ambiguous_refs)
1144                                break;
1145                } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
1146                        warning("ignoring dangling symref %s.", fullref);
1147                } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
1148                        warning("ignoring broken ref %s.", fullref);
1149                }
1150        }
1151        free(last_branch);
1152        return refs_found;
1153}
1154
1155int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
1156{
1157        char *last_branch = substitute_branch_name(&str, &len);
1158        const char **p;
1159        int logs_found = 0;
1160
1161        *log = NULL;
1162        for (p = ref_rev_parse_rules; *p; p++) {
1163                struct stat st;
1164                unsigned char hash[20];
1165                char path[PATH_MAX];
1166                const char *ref, *it;
1167
1168                mksnpath(path, sizeof(path), *p, len, str);
1169                ref = resolve_ref_unsafe(path, hash, 1, NULL);
1170                if (!ref)
1171                        continue;
1172                if (!stat(git_path("logs/%s", path), &st) &&
1173                    S_ISREG(st.st_mode))
1174                        it = path;
1175                else if (strcmp(ref, path) &&
1176                         !stat(git_path("logs/%s", ref), &st) &&
1177                         S_ISREG(st.st_mode))
1178                        it = ref;
1179                else
1180                        continue;
1181                if (!logs_found++) {
1182                        *log = xstrdup(it);
1183                        hashcpy(sha1, hash);
1184                }
1185                if (!warn_ambiguous_refs)
1186                        break;
1187        }
1188        free(last_branch);
1189        return logs_found;
1190}
1191
1192static struct ref_lock *lock_ref_sha1_basic(const char *refname,
1193                                            const unsigned char *old_sha1,
1194                                            int flags, int *type_p)
1195{
1196        char *ref_file;
1197        const char *orig_refname = refname;
1198        struct ref_lock *lock;
1199        int last_errno = 0;
1200        int type, lflags;
1201        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1202        int missing = 0;
1203
1204        lock = xcalloc(1, sizeof(struct ref_lock));
1205        lock->lock_fd = -1;
1206
1207        refname = resolve_ref_unsafe(refname, lock->old_sha1, mustexist, &type);
1208        if (!refname && errno == EISDIR) {
1209                /* we are trying to lock foo but we used to
1210                 * have foo/bar which now does not exist;
1211                 * it is normal for the empty directory 'foo'
1212                 * to remain.
1213                 */
1214                ref_file = git_path("%s", orig_refname);
1215                if (remove_empty_directories(ref_file)) {
1216                        last_errno = errno;
1217                        error("there are still refs under '%s'", orig_refname);
1218                        goto error_return;
1219                }
1220                refname = resolve_ref_unsafe(orig_refname, lock->old_sha1, mustexist, &type);
1221        }
1222        if (type_p)
1223            *type_p = type;
1224        if (!refname) {
1225                last_errno = errno;
1226                error("unable to resolve reference %s: %s",
1227                        orig_refname, strerror(errno));
1228                goto error_return;
1229        }
1230        missing = is_null_sha1(lock->old_sha1);
1231        /* When the ref did not exist and we are creating it,
1232         * make sure there is no existing ref that is packed
1233         * whose name begins with our refname, nor a ref whose
1234         * name is a proper prefix of our refname.
1235         */
1236        if (missing &&
1237             !is_refname_available(refname, NULL, get_packed_refs(get_ref_cache(NULL)))) {
1238                last_errno = ENOTDIR;
1239                goto error_return;
1240        }
1241
1242        lock->lk = xcalloc(1, sizeof(struct lock_file));
1243
1244        lflags = LOCK_DIE_ON_ERROR;
1245        if (flags & REF_NODEREF) {
1246                refname = orig_refname;
1247                lflags |= LOCK_NODEREF;
1248        }
1249        lock->ref_name = xstrdup(refname);
1250        lock->orig_ref_name = xstrdup(orig_refname);
1251        ref_file = git_path("%s", refname);
1252        if (missing)
1253                lock->force_write = 1;
1254        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1255                lock->force_write = 1;
1256
1257        if (safe_create_leading_directories(ref_file)) {
1258                last_errno = errno;
1259                error("unable to create directory for %s", ref_file);
1260                goto error_return;
1261        }
1262
1263        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1264        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1265
1266 error_return:
1267        unlock_ref(lock);
1268        errno = last_errno;
1269        return NULL;
1270}
1271
1272struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
1273{
1274        char refpath[PATH_MAX];
1275        if (check_refname_format(refname, 0))
1276                return NULL;
1277        strcpy(refpath, mkpath("refs/%s", refname));
1278        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1279}
1280
1281struct ref_lock *lock_any_ref_for_update(const char *refname,
1282                                         const unsigned char *old_sha1, int flags)
1283{
1284        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
1285                return NULL;
1286        return lock_ref_sha1_basic(refname, old_sha1, flags, NULL);
1287}
1288
1289static struct lock_file packlock;
1290
1291static int repack_without_ref(const char *refname)
1292{
1293        struct ref_array *packed;
1294        int fd, i;
1295
1296        packed = get_packed_refs(get_ref_cache(NULL));
1297        if (search_ref_array(packed, refname) == NULL)
1298                return 0;
1299        fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1300        if (fd < 0) {
1301                unable_to_lock_error(git_path("packed-refs"), errno);
1302                return error("cannot delete '%s' from packed refs", refname);
1303        }
1304
1305        for (i = 0; i < packed->nr; i++) {
1306                char line[PATH_MAX + 100];
1307                int len;
1308                struct ref_entry *ref = packed->refs[i];
1309
1310                if (!strcmp(refname, ref->name))
1311                        continue;
1312                len = snprintf(line, sizeof(line), "%s %s\n",
1313                               sha1_to_hex(ref->sha1), ref->name);
1314                /* this should not happen but just being defensive */
1315                if (len > sizeof(line))
1316                        die("too long a refname '%s'", ref->name);
1317                write_or_die(fd, line, len);
1318        }
1319        return commit_lock_file(&packlock);
1320}
1321
1322int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1323{
1324        struct ref_lock *lock;
1325        int err, i = 0, ret = 0, flag = 0;
1326
1327        lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1328        if (!lock)
1329                return 1;
1330        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1331                /* loose */
1332                const char *path;
1333
1334                if (!(delopt & REF_NODEREF)) {
1335                        i = strlen(lock->lk->filename) - 5; /* .lock */
1336                        lock->lk->filename[i] = 0;
1337                        path = lock->lk->filename;
1338                } else {
1339                        path = git_path("%s", refname);
1340                }
1341                err = unlink_or_warn(path);
1342                if (err && errno != ENOENT)
1343                        ret = 1;
1344
1345                if (!(delopt & REF_NODEREF))
1346                        lock->lk->filename[i] = '.';
1347        }
1348        /* removing the loose one could have resurrected an earlier
1349         * packed one.  Also, if it was not loose we need to repack
1350         * without it.
1351         */
1352        ret |= repack_without_ref(refname);
1353
1354        unlink_or_warn(git_path("logs/%s", lock->ref_name));
1355        invalidate_ref_cache(NULL);
1356        unlock_ref(lock);
1357        return ret;
1358}
1359
1360/*
1361 * People using contrib's git-new-workdir have .git/logs/refs ->
1362 * /some/other/path/.git/logs/refs, and that may live on another device.
1363 *
1364 * IOW, to avoid cross device rename errors, the temporary renamed log must
1365 * live into logs/refs.
1366 */
1367#define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1368
1369int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
1370{
1371        unsigned char sha1[20], orig_sha1[20];
1372        int flag = 0, logmoved = 0;
1373        struct ref_lock *lock;
1374        struct stat loginfo;
1375        int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
1376        const char *symref = NULL;
1377        struct ref_cache *refs = get_ref_cache(NULL);
1378
1379        if (log && S_ISLNK(loginfo.st_mode))
1380                return error("reflog for %s is a symlink", oldrefname);
1381
1382        symref = resolve_ref_unsafe(oldrefname, orig_sha1, 1, &flag);
1383        if (flag & REF_ISSYMREF)
1384                return error("refname %s is a symbolic ref, renaming it is not supported",
1385                        oldrefname);
1386        if (!symref)
1387                return error("refname %s not found", oldrefname);
1388
1389        if (!is_refname_available(newrefname, oldrefname, get_packed_refs(refs)))
1390                return 1;
1391
1392        if (!is_refname_available(newrefname, oldrefname, get_loose_refs(refs)))
1393                return 1;
1394
1395        if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
1396                return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1397                        oldrefname, strerror(errno));
1398
1399        if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
1400                error("unable to delete old %s", oldrefname);
1401                goto rollback;
1402        }
1403
1404        if (!read_ref_full(newrefname, sha1, 1, &flag) &&
1405            delete_ref(newrefname, sha1, REF_NODEREF)) {
1406                if (errno==EISDIR) {
1407                        if (remove_empty_directories(git_path("%s", newrefname))) {
1408                                error("Directory not empty: %s", newrefname);
1409                                goto rollback;
1410                        }
1411                } else {
1412                        error("unable to delete existing %s", newrefname);
1413                        goto rollback;
1414                }
1415        }
1416
1417        if (log && safe_create_leading_directories(git_path("logs/%s", newrefname))) {
1418                error("unable to create directory for %s", newrefname);
1419                goto rollback;
1420        }
1421
1422 retry:
1423        if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
1424                if (errno==EISDIR || errno==ENOTDIR) {
1425                        /*
1426                         * rename(a, b) when b is an existing
1427                         * directory ought to result in ISDIR, but
1428                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1429                         */
1430                        if (remove_empty_directories(git_path("logs/%s", newrefname))) {
1431                                error("Directory not empty: logs/%s", newrefname);
1432                                goto rollback;
1433                        }
1434                        goto retry;
1435                } else {
1436                        error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1437                                newrefname, strerror(errno));
1438                        goto rollback;
1439                }
1440        }
1441        logmoved = log;
1442
1443        lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
1444        if (!lock) {
1445                error("unable to lock %s for update", newrefname);
1446                goto rollback;
1447        }
1448        lock->force_write = 1;
1449        hashcpy(lock->old_sha1, orig_sha1);
1450        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1451                error("unable to write current sha1 into %s", newrefname);
1452                goto rollback;
1453        }
1454
1455        return 0;
1456
1457 rollback:
1458        lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
1459        if (!lock) {
1460                error("unable to lock %s for rollback", oldrefname);
1461                goto rollbacklog;
1462        }
1463
1464        lock->force_write = 1;
1465        flag = log_all_ref_updates;
1466        log_all_ref_updates = 0;
1467        if (write_ref_sha1(lock, orig_sha1, NULL))
1468                error("unable to write current sha1 into %s", oldrefname);
1469        log_all_ref_updates = flag;
1470
1471 rollbacklog:
1472        if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
1473                error("unable to restore logfile %s from %s: %s",
1474                        oldrefname, newrefname, strerror(errno));
1475        if (!logmoved && log &&
1476            rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
1477                error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1478                        oldrefname, strerror(errno));
1479
1480        return 1;
1481}
1482
1483int close_ref(struct ref_lock *lock)
1484{
1485        if (close_lock_file(lock->lk))
1486                return -1;
1487        lock->lock_fd = -1;
1488        return 0;
1489}
1490
1491int commit_ref(struct ref_lock *lock)
1492{
1493        if (commit_lock_file(lock->lk))
1494                return -1;
1495        lock->lock_fd = -1;
1496        return 0;
1497}
1498
1499void unlock_ref(struct ref_lock *lock)
1500{
1501        /* Do not free lock->lk -- atexit() still looks at them */
1502        if (lock->lk)
1503                rollback_lock_file(lock->lk);
1504        free(lock->ref_name);
1505        free(lock->orig_ref_name);
1506        free(lock);
1507}
1508
1509/*
1510 * copy the reflog message msg to buf, which has been allocated sufficiently
1511 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1512 * because reflog file is one line per entry.
1513 */
1514static int copy_msg(char *buf, const char *msg)
1515{
1516        char *cp = buf;
1517        char c;
1518        int wasspace = 1;
1519
1520        *cp++ = '\t';
1521        while ((c = *msg++)) {
1522                if (wasspace && isspace(c))
1523                        continue;
1524                wasspace = isspace(c);
1525                if (wasspace)
1526                        c = ' ';
1527                *cp++ = c;
1528        }
1529        while (buf < cp && isspace(cp[-1]))
1530                cp--;
1531        *cp++ = '\n';
1532        return cp - buf;
1533}
1534
1535int log_ref_setup(const char *refname, char *logfile, int bufsize)
1536{
1537        int logfd, oflags = O_APPEND | O_WRONLY;
1538
1539        git_snpath(logfile, bufsize, "logs/%s", refname);
1540        if (log_all_ref_updates &&
1541            (!prefixcmp(refname, "refs/heads/") ||
1542             !prefixcmp(refname, "refs/remotes/") ||
1543             !prefixcmp(refname, "refs/notes/") ||
1544             !strcmp(refname, "HEAD"))) {
1545                if (safe_create_leading_directories(logfile) < 0)
1546                        return error("unable to create directory for %s",
1547                                     logfile);
1548                oflags |= O_CREAT;
1549        }
1550
1551        logfd = open(logfile, oflags, 0666);
1552        if (logfd < 0) {
1553                if (!(oflags & O_CREAT) && errno == ENOENT)
1554                        return 0;
1555
1556                if ((oflags & O_CREAT) && errno == EISDIR) {
1557                        if (remove_empty_directories(logfile)) {
1558                                return error("There are still logs under '%s'",
1559                                             logfile);
1560                        }
1561                        logfd = open(logfile, oflags, 0666);
1562                }
1563
1564                if (logfd < 0)
1565                        return error("Unable to append to %s: %s",
1566                                     logfile, strerror(errno));
1567        }
1568
1569        adjust_shared_perm(logfile);
1570        close(logfd);
1571        return 0;
1572}
1573
1574static int log_ref_write(const char *refname, const unsigned char *old_sha1,
1575                         const unsigned char *new_sha1, const char *msg)
1576{
1577        int logfd, result, written, oflags = O_APPEND | O_WRONLY;
1578        unsigned maxlen, len;
1579        int msglen;
1580        char log_file[PATH_MAX];
1581        char *logrec;
1582        const char *committer;
1583
1584        if (log_all_ref_updates < 0)
1585                log_all_ref_updates = !is_bare_repository();
1586
1587        result = log_ref_setup(refname, log_file, sizeof(log_file));
1588        if (result)
1589                return result;
1590
1591        logfd = open(log_file, oflags);
1592        if (logfd < 0)
1593                return 0;
1594        msglen = msg ? strlen(msg) : 0;
1595        committer = git_committer_info(0);
1596        maxlen = strlen(committer) + msglen + 100;
1597        logrec = xmalloc(maxlen);
1598        len = sprintf(logrec, "%s %s %s\n",
1599                      sha1_to_hex(old_sha1),
1600                      sha1_to_hex(new_sha1),
1601                      committer);
1602        if (msglen)
1603                len += copy_msg(logrec + len - 1, msg) - 1;
1604        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
1605        free(logrec);
1606        if (close(logfd) != 0 || written != len)
1607                return error("Unable to append to %s", log_file);
1608        return 0;
1609}
1610
1611static int is_branch(const char *refname)
1612{
1613        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
1614}
1615
1616int write_ref_sha1(struct ref_lock *lock,
1617        const unsigned char *sha1, const char *logmsg)
1618{
1619        static char term = '\n';
1620        struct object *o;
1621
1622        if (!lock)
1623                return -1;
1624        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
1625                unlock_ref(lock);
1626                return 0;
1627        }
1628        o = parse_object(sha1);
1629        if (!o) {
1630                error("Trying to write ref %s with nonexistent object %s",
1631                        lock->ref_name, sha1_to_hex(sha1));
1632                unlock_ref(lock);
1633                return -1;
1634        }
1635        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
1636                error("Trying to write non-commit object %s to branch %s",
1637                        sha1_to_hex(sha1), lock->ref_name);
1638                unlock_ref(lock);
1639                return -1;
1640        }
1641        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
1642            write_in_full(lock->lock_fd, &term, 1) != 1
1643                || close_ref(lock) < 0) {
1644                error("Couldn't write %s", lock->lk->filename);
1645                unlock_ref(lock);
1646                return -1;
1647        }
1648        clear_loose_ref_cache(get_ref_cache(NULL));
1649        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
1650            (strcmp(lock->ref_name, lock->orig_ref_name) &&
1651             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
1652                unlock_ref(lock);
1653                return -1;
1654        }
1655        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
1656                /*
1657                 * Special hack: If a branch is updated directly and HEAD
1658                 * points to it (may happen on the remote side of a push
1659                 * for example) then logically the HEAD reflog should be
1660                 * updated too.
1661                 * A generic solution implies reverse symref information,
1662                 * but finding all symrefs pointing to the given branch
1663                 * would be rather costly for this rare event (the direct
1664                 * update of a branch) to be worth it.  So let's cheat and
1665                 * check with HEAD only which should cover 99% of all usage
1666                 * scenarios (even 100% of the default ones).
1667                 */
1668                unsigned char head_sha1[20];
1669                int head_flag;
1670                const char *head_ref;
1671                head_ref = resolve_ref_unsafe("HEAD", head_sha1, 1, &head_flag);
1672                if (head_ref && (head_flag & REF_ISSYMREF) &&
1673                    !strcmp(head_ref, lock->ref_name))
1674                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
1675        }
1676        if (commit_ref(lock)) {
1677                error("Couldn't set %s", lock->ref_name);
1678                unlock_ref(lock);
1679                return -1;
1680        }
1681        unlock_ref(lock);
1682        return 0;
1683}
1684
1685int create_symref(const char *ref_target, const char *refs_heads_master,
1686                  const char *logmsg)
1687{
1688        const char *lockpath;
1689        char ref[1000];
1690        int fd, len, written;
1691        char *git_HEAD = git_pathdup("%s", ref_target);
1692        unsigned char old_sha1[20], new_sha1[20];
1693
1694        if (logmsg && read_ref(ref_target, old_sha1))
1695                hashclr(old_sha1);
1696
1697        if (safe_create_leading_directories(git_HEAD) < 0)
1698                return error("unable to create directory for %s", git_HEAD);
1699
1700#ifndef NO_SYMLINK_HEAD
1701        if (prefer_symlink_refs) {
1702                unlink(git_HEAD);
1703                if (!symlink(refs_heads_master, git_HEAD))
1704                        goto done;
1705                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
1706        }
1707#endif
1708
1709        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
1710        if (sizeof(ref) <= len) {
1711                error("refname too long: %s", refs_heads_master);
1712                goto error_free_return;
1713        }
1714        lockpath = mkpath("%s.lock", git_HEAD);
1715        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
1716        if (fd < 0) {
1717                error("Unable to open %s for writing", lockpath);
1718                goto error_free_return;
1719        }
1720        written = write_in_full(fd, ref, len);
1721        if (close(fd) != 0 || written != len) {
1722                error("Unable to write to %s", lockpath);
1723                goto error_unlink_return;
1724        }
1725        if (rename(lockpath, git_HEAD) < 0) {
1726                error("Unable to create %s", git_HEAD);
1727                goto error_unlink_return;
1728        }
1729        if (adjust_shared_perm(git_HEAD)) {
1730                error("Unable to fix permissions on %s", lockpath);
1731        error_unlink_return:
1732                unlink_or_warn(lockpath);
1733        error_free_return:
1734                free(git_HEAD);
1735                return -1;
1736        }
1737
1738#ifndef NO_SYMLINK_HEAD
1739        done:
1740#endif
1741        if (logmsg && !read_ref(refs_heads_master, new_sha1))
1742                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
1743
1744        free(git_HEAD);
1745        return 0;
1746}
1747
1748static char *ref_msg(const char *line, const char *endp)
1749{
1750        const char *ep;
1751        line += 82;
1752        ep = memchr(line, '\n', endp - line);
1753        if (!ep)
1754                ep = endp;
1755        return xmemdupz(line, ep - line);
1756}
1757
1758int read_ref_at(const char *refname, unsigned long at_time, int cnt,
1759                unsigned char *sha1, char **msg,
1760                unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
1761{
1762        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
1763        char *tz_c;
1764        int logfd, tz, reccnt = 0;
1765        struct stat st;
1766        unsigned long date;
1767        unsigned char logged_sha1[20];
1768        void *log_mapped;
1769        size_t mapsz;
1770
1771        logfile = git_path("logs/%s", refname);
1772        logfd = open(logfile, O_RDONLY, 0);
1773        if (logfd < 0)
1774                die_errno("Unable to read log '%s'", logfile);
1775        fstat(logfd, &st);
1776        if (!st.st_size)
1777                die("Log %s is empty.", logfile);
1778        mapsz = xsize_t(st.st_size);
1779        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
1780        logdata = log_mapped;
1781        close(logfd);
1782
1783        lastrec = NULL;
1784        rec = logend = logdata + st.st_size;
1785        while (logdata < rec) {
1786                reccnt++;
1787                if (logdata < rec && *(rec-1) == '\n')
1788                        rec--;
1789                lastgt = NULL;
1790                while (logdata < rec && *(rec-1) != '\n') {
1791                        rec--;
1792                        if (*rec == '>')
1793                                lastgt = rec;
1794                }
1795                if (!lastgt)
1796                        die("Log %s is corrupt.", logfile);
1797                date = strtoul(lastgt + 1, &tz_c, 10);
1798                if (date <= at_time || cnt == 0) {
1799                        tz = strtoul(tz_c, NULL, 10);
1800                        if (msg)
1801                                *msg = ref_msg(rec, logend);
1802                        if (cutoff_time)
1803                                *cutoff_time = date;
1804                        if (cutoff_tz)
1805                                *cutoff_tz = tz;
1806                        if (cutoff_cnt)
1807                                *cutoff_cnt = reccnt - 1;
1808                        if (lastrec) {
1809                                if (get_sha1_hex(lastrec, logged_sha1))
1810                                        die("Log %s is corrupt.", logfile);
1811                                if (get_sha1_hex(rec + 41, sha1))
1812                                        die("Log %s is corrupt.", logfile);
1813                                if (hashcmp(logged_sha1, sha1)) {
1814                                        warning("Log %s has gap after %s.",
1815                                                logfile, show_date(date, tz, DATE_RFC2822));
1816                                }
1817                        }
1818                        else if (date == at_time) {
1819                                if (get_sha1_hex(rec + 41, sha1))
1820                                        die("Log %s is corrupt.", logfile);
1821                        }
1822                        else {
1823                                if (get_sha1_hex(rec + 41, logged_sha1))
1824                                        die("Log %s is corrupt.", logfile);
1825                                if (hashcmp(logged_sha1, sha1)) {
1826                                        warning("Log %s unexpectedly ended on %s.",
1827                                                logfile, show_date(date, tz, DATE_RFC2822));
1828                                }
1829                        }
1830                        munmap(log_mapped, mapsz);
1831                        return 0;
1832                }
1833                lastrec = rec;
1834                if (cnt > 0)
1835                        cnt--;
1836        }
1837
1838        rec = logdata;
1839        while (rec < logend && *rec != '>' && *rec != '\n')
1840                rec++;
1841        if (rec == logend || *rec == '\n')
1842                die("Log %s is corrupt.", logfile);
1843        date = strtoul(rec + 1, &tz_c, 10);
1844        tz = strtoul(tz_c, NULL, 10);
1845        if (get_sha1_hex(logdata, sha1))
1846                die("Log %s is corrupt.", logfile);
1847        if (is_null_sha1(sha1)) {
1848                if (get_sha1_hex(logdata + 41, sha1))
1849                        die("Log %s is corrupt.", logfile);
1850        }
1851        if (msg)
1852                *msg = ref_msg(logdata, logend);
1853        munmap(log_mapped, mapsz);
1854
1855        if (cutoff_time)
1856                *cutoff_time = date;
1857        if (cutoff_tz)
1858                *cutoff_tz = tz;
1859        if (cutoff_cnt)
1860                *cutoff_cnt = reccnt;
1861        return 1;
1862}
1863
1864int for_each_recent_reflog_ent(const char *refname, each_reflog_ent_fn fn, long ofs, void *cb_data)
1865{
1866        const char *logfile;
1867        FILE *logfp;
1868        struct strbuf sb = STRBUF_INIT;
1869        int ret = 0;
1870
1871        logfile = git_path("logs/%s", refname);
1872        logfp = fopen(logfile, "r");
1873        if (!logfp)
1874                return -1;
1875
1876        if (ofs) {
1877                struct stat statbuf;
1878                if (fstat(fileno(logfp), &statbuf) ||
1879                    statbuf.st_size < ofs ||
1880                    fseek(logfp, -ofs, SEEK_END) ||
1881                    strbuf_getwholeline(&sb, logfp, '\n')) {
1882                        fclose(logfp);
1883                        strbuf_release(&sb);
1884                        return -1;
1885                }
1886        }
1887
1888        while (!strbuf_getwholeline(&sb, logfp, '\n')) {
1889                unsigned char osha1[20], nsha1[20];
1890                char *email_end, *message;
1891                unsigned long timestamp;
1892                int tz;
1893
1894                /* old SP new SP name <email> SP time TAB msg LF */
1895                if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
1896                    get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
1897                    get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
1898                    !(email_end = strchr(sb.buf + 82, '>')) ||
1899                    email_end[1] != ' ' ||
1900                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
1901                    !message || message[0] != ' ' ||
1902                    (message[1] != '+' && message[1] != '-') ||
1903                    !isdigit(message[2]) || !isdigit(message[3]) ||
1904                    !isdigit(message[4]) || !isdigit(message[5]))
1905                        continue; /* corrupt? */
1906                email_end[1] = '\0';
1907                tz = strtol(message + 1, NULL, 10);
1908                if (message[6] != '\t')
1909                        message += 6;
1910                else
1911                        message += 7;
1912                ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
1913                         cb_data);
1914                if (ret)
1915                        break;
1916        }
1917        fclose(logfp);
1918        strbuf_release(&sb);
1919        return ret;
1920}
1921
1922int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
1923{
1924        return for_each_recent_reflog_ent(refname, fn, 0, cb_data);
1925}
1926
1927static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
1928{
1929        DIR *dir = opendir(git_path("logs/%s", base));
1930        int retval = 0;
1931
1932        if (dir) {
1933                struct dirent *de;
1934                int baselen = strlen(base);
1935                char *log = xmalloc(baselen + 257);
1936
1937                memcpy(log, base, baselen);
1938                if (baselen && base[baselen-1] != '/')
1939                        log[baselen++] = '/';
1940
1941                while ((de = readdir(dir)) != NULL) {
1942                        struct stat st;
1943                        int namelen;
1944
1945                        if (de->d_name[0] == '.')
1946                                continue;
1947                        namelen = strlen(de->d_name);
1948                        if (namelen > 255)
1949                                continue;
1950                        if (has_extension(de->d_name, ".lock"))
1951                                continue;
1952                        memcpy(log + baselen, de->d_name, namelen+1);
1953                        if (stat(git_path("logs/%s", log), &st) < 0)
1954                                continue;
1955                        if (S_ISDIR(st.st_mode)) {
1956                                retval = do_for_each_reflog(log, fn, cb_data);
1957                        } else {
1958                                unsigned char sha1[20];
1959                                if (read_ref_full(log, sha1, 0, NULL))
1960                                        retval = error("bad ref for %s", log);
1961                                else
1962                                        retval = fn(log, sha1, 0, cb_data);
1963                        }
1964                        if (retval)
1965                                break;
1966                }
1967                free(log);
1968                closedir(dir);
1969        }
1970        else if (*base)
1971                return errno;
1972        return retval;
1973}
1974
1975int for_each_reflog(each_ref_fn fn, void *cb_data)
1976{
1977        return do_for_each_reflog("", fn, cb_data);
1978}
1979
1980int update_ref(const char *action, const char *refname,
1981                const unsigned char *sha1, const unsigned char *oldval,
1982                int flags, enum action_on_err onerr)
1983{
1984        static struct ref_lock *lock;
1985        lock = lock_any_ref_for_update(refname, oldval, flags);
1986        if (!lock) {
1987                const char *str = "Cannot lock the ref '%s'.";
1988                switch (onerr) {
1989                case MSG_ON_ERR: error(str, refname); break;
1990                case DIE_ON_ERR: die(str, refname); break;
1991                case QUIET_ON_ERR: break;
1992                }
1993                return 1;
1994        }
1995        if (write_ref_sha1(lock, sha1, action) < 0) {
1996                const char *str = "Cannot update the ref '%s'.";
1997                switch (onerr) {
1998                case MSG_ON_ERR: error(str, refname); break;
1999                case DIE_ON_ERR: die(str, refname); break;
2000                case QUIET_ON_ERR: break;
2001                }
2002                return 1;
2003        }
2004        return 0;
2005}
2006
2007int ref_exists(const char *refname)
2008{
2009        unsigned char sha1[20];
2010        return !!resolve_ref_unsafe(refname, sha1, 1, NULL);
2011}
2012
2013struct ref *find_ref_by_name(const struct ref *list, const char *name)
2014{
2015        for ( ; list; list = list->next)
2016                if (!strcmp(list->name, name))
2017                        return (struct ref *)list;
2018        return NULL;
2019}
2020
2021/*
2022 * generate a format suitable for scanf from a ref_rev_parse_rules
2023 * rule, that is replace the "%.*s" spec with a "%s" spec
2024 */
2025static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
2026{
2027        char *spec;
2028
2029        spec = strstr(rule, "%.*s");
2030        if (!spec || strstr(spec + 4, "%.*s"))
2031                die("invalid rule in ref_rev_parse_rules: %s", rule);
2032
2033        /* copy all until spec */
2034        strncpy(scanf_fmt, rule, spec - rule);
2035        scanf_fmt[spec - rule] = '\0';
2036        /* copy new spec */
2037        strcat(scanf_fmt, "%s");
2038        /* copy remaining rule */
2039        strcat(scanf_fmt, spec + 4);
2040
2041        return;
2042}
2043
2044char *shorten_unambiguous_ref(const char *refname, int strict)
2045{
2046        int i;
2047        static char **scanf_fmts;
2048        static int nr_rules;
2049        char *short_name;
2050
2051        /* pre generate scanf formats from ref_rev_parse_rules[] */
2052        if (!nr_rules) {
2053                size_t total_len = 0;
2054
2055                /* the rule list is NULL terminated, count them first */
2056                for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
2057                        /* no +1 because strlen("%s") < strlen("%.*s") */
2058                        total_len += strlen(ref_rev_parse_rules[nr_rules]);
2059
2060                scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
2061
2062                total_len = 0;
2063                for (i = 0; i < nr_rules; i++) {
2064                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
2065                                        + total_len;
2066                        gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
2067                        total_len += strlen(ref_rev_parse_rules[i]);
2068                }
2069        }
2070
2071        /* bail out if there are no rules */
2072        if (!nr_rules)
2073                return xstrdup(refname);
2074
2075        /* buffer for scanf result, at most refname must fit */
2076        short_name = xstrdup(refname);
2077
2078        /* skip first rule, it will always match */
2079        for (i = nr_rules - 1; i > 0 ; --i) {
2080                int j;
2081                int rules_to_fail = i;
2082                int short_name_len;
2083
2084                if (1 != sscanf(refname, scanf_fmts[i], short_name))
2085                        continue;
2086
2087                short_name_len = strlen(short_name);
2088
2089                /*
2090                 * in strict mode, all (except the matched one) rules
2091                 * must fail to resolve to a valid non-ambiguous ref
2092                 */
2093                if (strict)
2094                        rules_to_fail = nr_rules;
2095
2096                /*
2097                 * check if the short name resolves to a valid ref,
2098                 * but use only rules prior to the matched one
2099                 */
2100                for (j = 0; j < rules_to_fail; j++) {
2101                        const char *rule = ref_rev_parse_rules[j];
2102                        char refname[PATH_MAX];
2103
2104                        /* skip matched rule */
2105                        if (i == j)
2106                                continue;
2107
2108                        /*
2109                         * the short name is ambiguous, if it resolves
2110                         * (with this previous rule) to a valid ref
2111                         * read_ref() returns 0 on success
2112                         */
2113                        mksnpath(refname, sizeof(refname),
2114                                 rule, short_name_len, short_name);
2115                        if (ref_exists(refname))
2116                                break;
2117                }
2118
2119                /*
2120                 * short name is non-ambiguous if all previous rules
2121                 * haven't resolved to a valid ref
2122                 */
2123                if (j == rules_to_fail)
2124                        return short_name;
2125        }
2126
2127        free(short_name);
2128        return xstrdup(refname);
2129}