refs.con commit refs: fix find_containing_dir() regression (663c129)
   1#include "cache.h"
   2#include "refs.h"
   3#include "object.h"
   4#include "tag.h"
   5#include "dir.h"
   6
   7/*
   8 * Make sure "ref" is something reasonable to have under ".git/refs/";
   9 * We do not like it if:
  10 *
  11 * - any path component of it begins with ".", or
  12 * - it has double dots "..", or
  13 * - it has ASCII control character, "~", "^", ":" or SP, anywhere, or
  14 * - it ends with a "/".
  15 * - it ends with ".lock"
  16 * - it contains a "\" (backslash)
  17 */
  18
  19/* Return true iff ch is not allowed in reference names. */
  20static inline int bad_ref_char(int ch)
  21{
  22        if (((unsigned) ch) <= ' ' || ch == 0x7f ||
  23            ch == '~' || ch == '^' || ch == ':' || ch == '\\')
  24                return 1;
  25        /* 2.13 Pattern Matching Notation */
  26        if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
  27                return 1;
  28        return 0;
  29}
  30
  31/*
  32 * Try to read one refname component from the front of refname.  Return
  33 * the length of the component found, or -1 if the component is not
  34 * legal.
  35 */
  36static int check_refname_component(const char *refname, int flags)
  37{
  38        const char *cp;
  39        char last = '\0';
  40
  41        for (cp = refname; ; cp++) {
  42                char ch = *cp;
  43                if (ch == '\0' || ch == '/')
  44                        break;
  45                if (bad_ref_char(ch))
  46                        return -1; /* Illegal character in refname. */
  47                if (last == '.' && ch == '.')
  48                        return -1; /* Refname contains "..". */
  49                if (last == '@' && ch == '{')
  50                        return -1; /* Refname contains "@{". */
  51                last = ch;
  52        }
  53        if (cp == refname)
  54                return 0; /* Component has zero length. */
  55        if (refname[0] == '.') {
  56                if (!(flags & REFNAME_DOT_COMPONENT))
  57                        return -1; /* Component starts with '.'. */
  58                /*
  59                 * Even if leading dots are allowed, don't allow "."
  60                 * as a component (".." is prevented by a rule above).
  61                 */
  62                if (refname[1] == '\0')
  63                        return -1; /* Component equals ".". */
  64        }
  65        if (cp - refname >= 5 && !memcmp(cp - 5, ".lock", 5))
  66                return -1; /* Refname ends with ".lock". */
  67        return cp - refname;
  68}
  69
  70int check_refname_format(const char *refname, int flags)
  71{
  72        int component_len, component_count = 0;
  73
  74        while (1) {
  75                /* We are at the start of a path component. */
  76                component_len = check_refname_component(refname, flags);
  77                if (component_len <= 0) {
  78                        if ((flags & REFNAME_REFSPEC_PATTERN) &&
  79                                        refname[0] == '*' &&
  80                                        (refname[1] == '\0' || refname[1] == '/')) {
  81                                /* Accept one wildcard as a full refname component. */
  82                                flags &= ~REFNAME_REFSPEC_PATTERN;
  83                                component_len = 1;
  84                        } else {
  85                                return -1;
  86                        }
  87                }
  88                component_count++;
  89                if (refname[component_len] == '\0')
  90                        break;
  91                /* Skip to next component. */
  92                refname += component_len + 1;
  93        }
  94
  95        if (refname[component_len - 1] == '.')
  96                return -1; /* Refname ends with '.'. */
  97        if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
  98                return -1; /* Refname has only one component. */
  99        return 0;
 100}
 101
 102struct ref_entry;
 103
 104/*
 105 * Information used (along with the information in ref_entry) to
 106 * describe a single cached reference.  This data structure only
 107 * occurs embedded in a union in struct ref_entry, and only when
 108 * (ref_entry->flag & REF_DIR) is zero.
 109 */
 110struct ref_value {
 111        unsigned char sha1[20];
 112        unsigned char peeled[20];
 113};
 114
 115struct ref_cache;
 116
 117/*
 118 * Information used (along with the information in ref_entry) to
 119 * describe a level in the hierarchy of references.  This data
 120 * structure only occurs embedded in a union in struct ref_entry, and
 121 * only when (ref_entry.flag & REF_DIR) is set.  In that case,
 122 * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
 123 * in the directory have already been read:
 124 *
 125 *     (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
 126 *         or packed references, already read.
 127 *
 128 *     (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
 129 *         references that hasn't been read yet (nor has any of its
 130 *         subdirectories).
 131 *
 132 * Entries within a directory are stored within a growable array of
 133 * pointers to ref_entries (entries, nr, alloc).  Entries 0 <= i <
 134 * sorted are sorted by their component name in strcmp() order and the
 135 * remaining entries are unsorted.
 136 *
 137 * Loose references are read lazily, one directory at a time.  When a
 138 * directory of loose references is read, then all of the references
 139 * in that directory are stored, and REF_INCOMPLETE stubs are created
 140 * for any subdirectories, but the subdirectories themselves are not
 141 * read.  The reading is triggered by get_ref_dir().
 142 */
 143struct ref_dir {
 144        int nr, alloc;
 145
 146        /*
 147         * Entries with index 0 <= i < sorted are sorted by name.  New
 148         * entries are appended to the list unsorted, and are sorted
 149         * only when required; thus we avoid the need to sort the list
 150         * after the addition of every reference.
 151         */
 152        int sorted;
 153
 154        /* A pointer to the ref_cache that contains this ref_dir. */
 155        struct ref_cache *ref_cache;
 156
 157        struct ref_entry **entries;
 158};
 159
 160/* ISSYMREF=0x01, ISPACKED=0x02, and ISBROKEN=0x04 are public interfaces */
 161#define REF_KNOWS_PEELED 0x08
 162
 163/* ref_entry represents a directory of references */
 164#define REF_DIR 0x10
 165
 166/*
 167 * Entry has not yet been read from disk (used only for REF_DIR
 168 * entries representing loose references)
 169 */
 170#define REF_INCOMPLETE 0x20
 171
 172/*
 173 * A ref_entry represents either a reference or a "subdirectory" of
 174 * references.
 175 *
 176 * Each directory in the reference namespace is represented by a
 177 * ref_entry with (flags & REF_DIR) set and containing a subdir member
 178 * that holds the entries in that directory that have been read so
 179 * far.  If (flags & REF_INCOMPLETE) is set, then the directory and
 180 * its subdirectories haven't been read yet.  REF_INCOMPLETE is only
 181 * used for loose reference directories.
 182 *
 183 * References are represented by a ref_entry with (flags & REF_DIR)
 184 * unset and a value member that describes the reference's value.  The
 185 * flag member is at the ref_entry level, but it is also needed to
 186 * interpret the contents of the value field (in other words, a
 187 * ref_value object is not very much use without the enclosing
 188 * ref_entry).
 189 *
 190 * Reference names cannot end with slash and directories' names are
 191 * always stored with a trailing slash (except for the top-level
 192 * directory, which is always denoted by "").  This has two nice
 193 * consequences: (1) when the entries in each subdir are sorted
 194 * lexicographically by name (as they usually are), the references in
 195 * a whole tree can be generated in lexicographic order by traversing
 196 * the tree in left-to-right, depth-first order; (2) the names of
 197 * references and subdirectories cannot conflict, and therefore the
 198 * presence of an empty subdirectory does not block the creation of a
 199 * similarly-named reference.  (The fact that reference names with the
 200 * same leading components can conflict *with each other* is a
 201 * separate issue that is regulated by is_refname_available().)
 202 *
 203 * Please note that the name field contains the fully-qualified
 204 * reference (or subdirectory) name.  Space could be saved by only
 205 * storing the relative names.  But that would require the full names
 206 * to be generated on the fly when iterating in do_for_each_ref(), and
 207 * would break callback functions, who have always been able to assume
 208 * that the name strings that they are passed will not be freed during
 209 * the iteration.
 210 */
 211struct ref_entry {
 212        unsigned char flag; /* ISSYMREF? ISPACKED? */
 213        union {
 214                struct ref_value value; /* if not (flags&REF_DIR) */
 215                struct ref_dir subdir; /* if (flags&REF_DIR) */
 216        } u;
 217        /*
 218         * The full name of the reference (e.g., "refs/heads/master")
 219         * or the full name of the directory with a trailing slash
 220         * (e.g., "refs/heads/"):
 221         */
 222        char name[FLEX_ARRAY];
 223};
 224
 225static void read_loose_refs(const char *dirname, struct ref_dir *dir);
 226
 227static struct ref_dir *get_ref_dir(struct ref_entry *entry)
 228{
 229        struct ref_dir *dir;
 230        assert(entry->flag & REF_DIR);
 231        dir = &entry->u.subdir;
 232        if (entry->flag & REF_INCOMPLETE) {
 233                read_loose_refs(entry->name, dir);
 234                entry->flag &= ~REF_INCOMPLETE;
 235        }
 236        return dir;
 237}
 238
 239static struct ref_entry *create_ref_entry(const char *refname,
 240                                          const unsigned char *sha1, int flag,
 241                                          int check_name)
 242{
 243        int len;
 244        struct ref_entry *ref;
 245
 246        if (check_name &&
 247            check_refname_format(refname, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
 248                die("Reference has invalid format: '%s'", refname);
 249        len = strlen(refname) + 1;
 250        ref = xmalloc(sizeof(struct ref_entry) + len);
 251        hashcpy(ref->u.value.sha1, sha1);
 252        hashclr(ref->u.value.peeled);
 253        memcpy(ref->name, refname, len);
 254        ref->flag = flag;
 255        return ref;
 256}
 257
 258static void clear_ref_dir(struct ref_dir *dir);
 259
 260static void free_ref_entry(struct ref_entry *entry)
 261{
 262        if (entry->flag & REF_DIR)
 263                clear_ref_dir(get_ref_dir(entry));
 264        free(entry);
 265}
 266
 267/*
 268 * Add a ref_entry to the end of dir (unsorted).  Entry is always
 269 * stored directly in dir; no recursion into subdirectories is
 270 * done.
 271 */
 272static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
 273{
 274        ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
 275        dir->entries[dir->nr++] = entry;
 276}
 277
 278/*
 279 * Clear and free all entries in dir, recursively.
 280 */
 281static void clear_ref_dir(struct ref_dir *dir)
 282{
 283        int i;
 284        for (i = 0; i < dir->nr; i++)
 285                free_ref_entry(dir->entries[i]);
 286        free(dir->entries);
 287        dir->sorted = dir->nr = dir->alloc = 0;
 288        dir->entries = NULL;
 289}
 290
 291/*
 292 * Create a struct ref_entry object for the specified dirname.
 293 * dirname is the name of the directory with a trailing slash (e.g.,
 294 * "refs/heads/") or "" for the top-level directory.
 295 */
 296static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
 297                                          const char *dirname, int incomplete)
 298{
 299        struct ref_entry *direntry;
 300        int len = strlen(dirname);
 301        direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
 302        memcpy(direntry->name, dirname, len + 1);
 303        direntry->u.subdir.ref_cache = ref_cache;
 304        direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
 305        return direntry;
 306}
 307
 308static int ref_entry_cmp(const void *a, const void *b)
 309{
 310        struct ref_entry *one = *(struct ref_entry **)a;
 311        struct ref_entry *two = *(struct ref_entry **)b;
 312        return strcmp(one->name, two->name);
 313}
 314
 315static void sort_ref_dir(struct ref_dir *dir);
 316
 317/*
 318 * Return the entry with the given refname from the ref_dir
 319 * (non-recursively), sorting dir if necessary.  Return NULL if no
 320 * such entry is found.  dir must already be complete.
 321 */
 322static struct ref_entry *search_ref_dir(struct ref_dir *dir, const char *refname)
 323{
 324        struct ref_entry *e, **r;
 325        int len;
 326
 327        if (refname == NULL || !dir->nr)
 328                return NULL;
 329
 330        sort_ref_dir(dir);
 331
 332        len = strlen(refname) + 1;
 333        e = xmalloc(sizeof(struct ref_entry) + len);
 334        memcpy(e->name, refname, len);
 335
 336        r = bsearch(&e, dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
 337
 338        free(e);
 339
 340        if (r == NULL)
 341                return NULL;
 342
 343        return *r;
 344}
 345
 346/*
 347 * Search for a directory entry directly within dir (without
 348 * recursing).  Sort dir if necessary.  subdirname must be a directory
 349 * name (i.e., end in '/').  If mkdir is set, then create the
 350 * directory if it is missing; otherwise, return NULL if the desired
 351 * directory cannot be found.  dir must already be complete.
 352 */
 353static struct ref_dir *search_for_subdir(struct ref_dir *dir,
 354                                         const char *subdirname, int mkdir)
 355{
 356        struct ref_entry *entry = search_ref_dir(dir, subdirname);
 357        if (!entry) {
 358                if (!mkdir)
 359                        return NULL;
 360                /*
 361                 * Since dir is complete, the absence of a subdir
 362                 * means that the subdir really doesn't exist;
 363                 * therefore, create an empty record for it but mark
 364                 * the record complete.
 365                 */
 366                entry = create_dir_entry(dir->ref_cache, subdirname, 0);
 367                add_entry_to_dir(dir, entry);
 368        }
 369        return get_ref_dir(entry);
 370}
 371
 372/*
 373 * If refname is a reference name, find the ref_dir within the dir
 374 * tree that should hold refname.  If refname is a directory name
 375 * (i.e., ends in '/'), then return that ref_dir itself.  dir must
 376 * represent the top-level directory and must already be complete.
 377 * Sort ref_dirs and recurse into subdirectories as necessary.  If
 378 * mkdir is set, then create any missing directories; otherwise,
 379 * return NULL if the desired directory cannot be found.
 380 */
 381static struct ref_dir *find_containing_dir(struct ref_dir *dir,
 382                                           const char *refname, int mkdir)
 383{
 384        struct strbuf dirname;
 385        const char *slash;
 386        strbuf_init(&dirname, PATH_MAX);
 387        for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
 388                struct ref_dir *subdir;
 389                strbuf_add(&dirname,
 390                           refname + dirname.len,
 391                           (slash + 1) - (refname + dirname.len));
 392                subdir = search_for_subdir(dir, dirname.buf, mkdir);
 393                if (!subdir) {
 394                        dir = NULL;
 395                        break;
 396                }
 397                dir = subdir;
 398        }
 399
 400        strbuf_release(&dirname);
 401        return dir;
 402}
 403
 404/*
 405 * Find the value entry with the given name in dir, sorting ref_dirs
 406 * and recursing into subdirectories as necessary.  If the name is not
 407 * found or it corresponds to a directory entry, return NULL.
 408 */
 409static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
 410{
 411        struct ref_entry *entry;
 412        dir = find_containing_dir(dir, refname, 0);
 413        if (!dir)
 414                return NULL;
 415        entry = search_ref_dir(dir, refname);
 416        return (entry && !(entry->flag & REF_DIR)) ? entry : NULL;
 417}
 418
 419/*
 420 * Add a ref_entry to the ref_dir (unsorted), recursing into
 421 * subdirectories as necessary.  dir must represent the top-level
 422 * directory.  Return 0 on success.
 423 */
 424static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
 425{
 426        dir = find_containing_dir(dir, ref->name, 1);
 427        if (!dir)
 428                return -1;
 429        add_entry_to_dir(dir, ref);
 430        return 0;
 431}
 432
 433/*
 434 * Emit a warning and return true iff ref1 and ref2 have the same name
 435 * and the same sha1.  Die if they have the same name but different
 436 * sha1s.
 437 */
 438static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
 439{
 440        if (strcmp(ref1->name, ref2->name))
 441                return 0;
 442
 443        /* Duplicate name; make sure that they don't conflict: */
 444
 445        if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
 446                /* This is impossible by construction */
 447                die("Reference directory conflict: %s", ref1->name);
 448
 449        if (hashcmp(ref1->u.value.sha1, ref2->u.value.sha1))
 450                die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
 451
 452        warning("Duplicated ref: %s", ref1->name);
 453        return 1;
 454}
 455
 456/*
 457 * Sort the entries in dir non-recursively (if they are not already
 458 * sorted) and remove any duplicate entries.
 459 */
 460static void sort_ref_dir(struct ref_dir *dir)
 461{
 462        int i, j;
 463        struct ref_entry *last = NULL;
 464
 465        /*
 466         * This check also prevents passing a zero-length array to qsort(),
 467         * which is a problem on some platforms.
 468         */
 469        if (dir->sorted == dir->nr)
 470                return;
 471
 472        qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
 473
 474        /* Remove any duplicates: */
 475        for (i = 0, j = 0; j < dir->nr; j++) {
 476                struct ref_entry *entry = dir->entries[j];
 477                if (last && is_dup_ref(last, entry))
 478                        free_ref_entry(entry);
 479                else
 480                        last = dir->entries[i++] = entry;
 481        }
 482        dir->sorted = dir->nr = i;
 483}
 484
 485#define DO_FOR_EACH_INCLUDE_BROKEN 01
 486
 487static struct ref_entry *current_ref;
 488
 489static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 490                      int flags, void *cb_data, struct ref_entry *entry)
 491{
 492        int retval;
 493        if (prefixcmp(entry->name, base))
 494                return 0;
 495
 496        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 497                if (entry->flag & REF_ISBROKEN)
 498                        return 0; /* ignore broken refs e.g. dangling symref */
 499                if (!has_sha1_file(entry->u.value.sha1)) {
 500                        error("%s does not point to a valid object!", entry->name);
 501                        return 0;
 502                }
 503        }
 504        current_ref = entry;
 505        retval = fn(entry->name + trim, entry->u.value.sha1, entry->flag, cb_data);
 506        current_ref = NULL;
 507        return retval;
 508}
 509
 510/*
 511 * Call fn for each reference in dir that has index in the range
 512 * offset <= index < dir->nr.  Recurse into subdirectories that are in
 513 * that index range, sorting them before iterating.  This function
 514 * does not sort dir itself; it should be sorted beforehand.
 515 */
 516static int do_for_each_ref_in_dir(struct ref_dir *dir, int offset,
 517                                  const char *base,
 518                                  each_ref_fn fn, int trim, int flags, void *cb_data)
 519{
 520        int i;
 521        assert(dir->sorted == dir->nr);
 522        for (i = offset; i < dir->nr; i++) {
 523                struct ref_entry *entry = dir->entries[i];
 524                int retval;
 525                if (entry->flag & REF_DIR) {
 526                        struct ref_dir *subdir = get_ref_dir(entry);
 527                        sort_ref_dir(subdir);
 528                        retval = do_for_each_ref_in_dir(subdir, 0,
 529                                                        base, fn, trim, flags, cb_data);
 530                } else {
 531                        retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 532                }
 533                if (retval)
 534                        return retval;
 535        }
 536        return 0;
 537}
 538
 539/*
 540 * Call fn for each reference in the union of dir1 and dir2, in order
 541 * by refname.  Recurse into subdirectories.  If a value entry appears
 542 * in both dir1 and dir2, then only process the version that is in
 543 * dir2.  The input dirs must already be sorted, but subdirs will be
 544 * sorted as needed.
 545 */
 546static int do_for_each_ref_in_dirs(struct ref_dir *dir1,
 547                                   struct ref_dir *dir2,
 548                                   const char *base, each_ref_fn fn, int trim,
 549                                   int flags, void *cb_data)
 550{
 551        int retval;
 552        int i1 = 0, i2 = 0;
 553
 554        assert(dir1->sorted == dir1->nr);
 555        assert(dir2->sorted == dir2->nr);
 556        while (1) {
 557                struct ref_entry *e1, *e2;
 558                int cmp;
 559                if (i1 == dir1->nr) {
 560                        return do_for_each_ref_in_dir(dir2, i2,
 561                                                      base, fn, trim, flags, cb_data);
 562                }
 563                if (i2 == dir2->nr) {
 564                        return do_for_each_ref_in_dir(dir1, i1,
 565                                                      base, fn, trim, flags, cb_data);
 566                }
 567                e1 = dir1->entries[i1];
 568                e2 = dir2->entries[i2];
 569                cmp = strcmp(e1->name, e2->name);
 570                if (cmp == 0) {
 571                        if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
 572                                /* Both are directories; descend them in parallel. */
 573                                struct ref_dir *subdir1 = get_ref_dir(e1);
 574                                struct ref_dir *subdir2 = get_ref_dir(e2);
 575                                sort_ref_dir(subdir1);
 576                                sort_ref_dir(subdir2);
 577                                retval = do_for_each_ref_in_dirs(
 578                                                subdir1, subdir2,
 579                                                base, fn, trim, flags, cb_data);
 580                                i1++;
 581                                i2++;
 582                        } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
 583                                /* Both are references; ignore the one from dir1. */
 584                                retval = do_one_ref(base, fn, trim, flags, cb_data, e2);
 585                                i1++;
 586                                i2++;
 587                        } else {
 588                                die("conflict between reference and directory: %s",
 589                                    e1->name);
 590                        }
 591                } else {
 592                        struct ref_entry *e;
 593                        if (cmp < 0) {
 594                                e = e1;
 595                                i1++;
 596                        } else {
 597                                e = e2;
 598                                i2++;
 599                        }
 600                        if (e->flag & REF_DIR) {
 601                                struct ref_dir *subdir = get_ref_dir(e);
 602                                sort_ref_dir(subdir);
 603                                retval = do_for_each_ref_in_dir(
 604                                                subdir, 0,
 605                                                base, fn, trim, flags, cb_data);
 606                        } else {
 607                                retval = do_one_ref(base, fn, trim, flags, cb_data, e);
 608                        }
 609                }
 610                if (retval)
 611                        return retval;
 612        }
 613        if (i1 < dir1->nr)
 614                return do_for_each_ref_in_dir(dir1, i1,
 615                                              base, fn, trim, flags, cb_data);
 616        if (i2 < dir2->nr)
 617                return do_for_each_ref_in_dir(dir2, i2,
 618                                              base, fn, trim, flags, cb_data);
 619        return 0;
 620}
 621
 622/*
 623 * Return true iff refname1 and refname2 conflict with each other.
 624 * Two reference names conflict if one of them exactly matches the
 625 * leading components of the other; e.g., "foo/bar" conflicts with
 626 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
 627 * "foo/barbados".
 628 */
 629static int names_conflict(const char *refname1, const char *refname2)
 630{
 631        for (; *refname1 && *refname1 == *refname2; refname1++, refname2++)
 632                ;
 633        return (*refname1 == '\0' && *refname2 == '/')
 634                || (*refname1 == '/' && *refname2 == '\0');
 635}
 636
 637struct name_conflict_cb {
 638        const char *refname;
 639        const char *oldrefname;
 640        const char *conflicting_refname;
 641};
 642
 643static int name_conflict_fn(const char *existingrefname, const unsigned char *sha1,
 644                            int flags, void *cb_data)
 645{
 646        struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
 647        if (data->oldrefname && !strcmp(data->oldrefname, existingrefname))
 648                return 0;
 649        if (names_conflict(data->refname, existingrefname)) {
 650                data->conflicting_refname = existingrefname;
 651                return 1;
 652        }
 653        return 0;
 654}
 655
 656/*
 657 * Return true iff a reference named refname could be created without
 658 * conflicting with the name of an existing reference in array.  If
 659 * oldrefname is non-NULL, ignore potential conflicts with oldrefname
 660 * (e.g., because oldrefname is scheduled for deletion in the same
 661 * operation).
 662 */
 663static int is_refname_available(const char *refname, const char *oldrefname,
 664                                struct ref_dir *dir)
 665{
 666        struct name_conflict_cb data;
 667        data.refname = refname;
 668        data.oldrefname = oldrefname;
 669        data.conflicting_refname = NULL;
 670
 671        sort_ref_dir(dir);
 672        if (do_for_each_ref_in_dir(dir, 0, "", name_conflict_fn,
 673                                   0, DO_FOR_EACH_INCLUDE_BROKEN,
 674                                   &data)) {
 675                error("'%s' exists; cannot create '%s'",
 676                      data.conflicting_refname, refname);
 677                return 0;
 678        }
 679        return 1;
 680}
 681
 682/*
 683 * Future: need to be in "struct repository"
 684 * when doing a full libification.
 685 */
 686static struct ref_cache {
 687        struct ref_cache *next;
 688        struct ref_entry *loose;
 689        struct ref_entry *packed;
 690        /* The submodule name, or "" for the main repo. */
 691        char name[FLEX_ARRAY];
 692} *ref_cache;
 693
 694static void clear_packed_ref_cache(struct ref_cache *refs)
 695{
 696        if (refs->packed) {
 697                free_ref_entry(refs->packed);
 698                refs->packed = NULL;
 699        }
 700}
 701
 702static void clear_loose_ref_cache(struct ref_cache *refs)
 703{
 704        if (refs->loose) {
 705                free_ref_entry(refs->loose);
 706                refs->loose = NULL;
 707        }
 708}
 709
 710static struct ref_cache *create_ref_cache(const char *submodule)
 711{
 712        int len;
 713        struct ref_cache *refs;
 714        if (!submodule)
 715                submodule = "";
 716        len = strlen(submodule) + 1;
 717        refs = xcalloc(1, sizeof(struct ref_cache) + len);
 718        memcpy(refs->name, submodule, len);
 719        return refs;
 720}
 721
 722/*
 723 * Return a pointer to a ref_cache for the specified submodule. For
 724 * the main repository, use submodule==NULL. The returned structure
 725 * will be allocated and initialized but not necessarily populated; it
 726 * should not be freed.
 727 */
 728static struct ref_cache *get_ref_cache(const char *submodule)
 729{
 730        struct ref_cache *refs = ref_cache;
 731        if (!submodule)
 732                submodule = "";
 733        while (refs) {
 734                if (!strcmp(submodule, refs->name))
 735                        return refs;
 736                refs = refs->next;
 737        }
 738
 739        refs = create_ref_cache(submodule);
 740        refs->next = ref_cache;
 741        ref_cache = refs;
 742        return refs;
 743}
 744
 745void invalidate_ref_cache(const char *submodule)
 746{
 747        struct ref_cache *refs = get_ref_cache(submodule);
 748        clear_packed_ref_cache(refs);
 749        clear_loose_ref_cache(refs);
 750}
 751
 752/*
 753 * Parse one line from a packed-refs file.  Write the SHA1 to sha1.
 754 * Return a pointer to the refname within the line (null-terminated),
 755 * or NULL if there was a problem.
 756 */
 757static const char *parse_ref_line(char *line, unsigned char *sha1)
 758{
 759        /*
 760         * 42: the answer to everything.
 761         *
 762         * In this case, it happens to be the answer to
 763         *  40 (length of sha1 hex representation)
 764         *  +1 (space in between hex and name)
 765         *  +1 (newline at the end of the line)
 766         */
 767        int len = strlen(line) - 42;
 768
 769        if (len <= 0)
 770                return NULL;
 771        if (get_sha1_hex(line, sha1) < 0)
 772                return NULL;
 773        if (!isspace(line[40]))
 774                return NULL;
 775        line += 41;
 776        if (isspace(*line))
 777                return NULL;
 778        if (line[len] != '\n')
 779                return NULL;
 780        line[len] = 0;
 781
 782        return line;
 783}
 784
 785static void read_packed_refs(FILE *f, struct ref_dir *dir)
 786{
 787        struct ref_entry *last = NULL;
 788        char refline[PATH_MAX];
 789        int flag = REF_ISPACKED;
 790
 791        while (fgets(refline, sizeof(refline), f)) {
 792                unsigned char sha1[20];
 793                const char *refname;
 794                static const char header[] = "# pack-refs with:";
 795
 796                if (!strncmp(refline, header, sizeof(header)-1)) {
 797                        const char *traits = refline + sizeof(header) - 1;
 798                        if (strstr(traits, " peeled "))
 799                                flag |= REF_KNOWS_PEELED;
 800                        /* perhaps other traits later as well */
 801                        continue;
 802                }
 803
 804                refname = parse_ref_line(refline, sha1);
 805                if (refname) {
 806                        last = create_ref_entry(refname, sha1, flag, 1);
 807                        add_ref(dir, last);
 808                        continue;
 809                }
 810                if (last &&
 811                    refline[0] == '^' &&
 812                    strlen(refline) == 42 &&
 813                    refline[41] == '\n' &&
 814                    !get_sha1_hex(refline + 1, sha1))
 815                        hashcpy(last->u.value.peeled, sha1);
 816        }
 817}
 818
 819static struct ref_dir *get_packed_refs(struct ref_cache *refs)
 820{
 821        if (!refs->packed) {
 822                const char *packed_refs_file;
 823                FILE *f;
 824
 825                refs->packed = create_dir_entry(refs, "", 0);
 826                if (*refs->name)
 827                        packed_refs_file = git_path_submodule(refs->name, "packed-refs");
 828                else
 829                        packed_refs_file = git_path("packed-refs");
 830                f = fopen(packed_refs_file, "r");
 831                if (f) {
 832                        read_packed_refs(f, get_ref_dir(refs->packed));
 833                        fclose(f);
 834                }
 835        }
 836        return get_ref_dir(refs->packed);
 837}
 838
 839void add_packed_ref(const char *refname, const unsigned char *sha1)
 840{
 841        add_ref(get_packed_refs(get_ref_cache(NULL)),
 842                        create_ref_entry(refname, sha1, REF_ISPACKED, 1));
 843}
 844
 845/*
 846 * Read the loose references from the namespace dirname into dir
 847 * (without recursing).  dirname must end with '/'.  dir must be the
 848 * directory entry corresponding to dirname.
 849 */
 850static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 851{
 852        struct ref_cache *refs = dir->ref_cache;
 853        DIR *d;
 854        const char *path;
 855        struct dirent *de;
 856        int dirnamelen = strlen(dirname);
 857        struct strbuf refname;
 858
 859        if (*refs->name)
 860                path = git_path_submodule(refs->name, "%s", dirname);
 861        else
 862                path = git_path("%s", dirname);
 863
 864        d = opendir(path);
 865        if (!d)
 866                return;
 867
 868        strbuf_init(&refname, dirnamelen + 257);
 869        strbuf_add(&refname, dirname, dirnamelen);
 870
 871        while ((de = readdir(d)) != NULL) {
 872                unsigned char sha1[20];
 873                struct stat st;
 874                int flag;
 875                const char *refdir;
 876
 877                if (de->d_name[0] == '.')
 878                        continue;
 879                if (has_extension(de->d_name, ".lock"))
 880                        continue;
 881                strbuf_addstr(&refname, de->d_name);
 882                refdir = *refs->name
 883                        ? git_path_submodule(refs->name, "%s", refname.buf)
 884                        : git_path("%s", refname.buf);
 885                if (stat(refdir, &st) < 0) {
 886                        ; /* silently ignore */
 887                } else if (S_ISDIR(st.st_mode)) {
 888                        strbuf_addch(&refname, '/');
 889                        add_entry_to_dir(dir,
 890                                         create_dir_entry(refs, refname.buf, 1));
 891                } else {
 892                        if (*refs->name) {
 893                                hashclr(sha1);
 894                                flag = 0;
 895                                if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) {
 896                                        hashclr(sha1);
 897                                        flag |= REF_ISBROKEN;
 898                                }
 899                        } else if (read_ref_full(refname.buf, sha1, 1, &flag)) {
 900                                hashclr(sha1);
 901                                flag |= REF_ISBROKEN;
 902                        }
 903                        add_entry_to_dir(dir,
 904                                         create_ref_entry(refname.buf, sha1, flag, 1));
 905                }
 906                strbuf_setlen(&refname, dirnamelen);
 907        }
 908        strbuf_release(&refname);
 909        closedir(d);
 910}
 911
 912static struct ref_dir *get_loose_refs(struct ref_cache *refs)
 913{
 914        if (!refs->loose) {
 915                /*
 916                 * Mark the top-level directory complete because we
 917                 * are about to read the only subdirectory that can
 918                 * hold references:
 919                 */
 920                refs->loose = create_dir_entry(refs, "", 0);
 921                /*
 922                 * Create an incomplete entry for "refs/":
 923                 */
 924                add_entry_to_dir(get_ref_dir(refs->loose),
 925                                 create_dir_entry(refs, "refs/", 1));
 926        }
 927        return get_ref_dir(refs->loose);
 928}
 929
 930/* We allow "recursive" symbolic refs. Only within reason, though */
 931#define MAXDEPTH 5
 932#define MAXREFLEN (1024)
 933
 934/*
 935 * Called by resolve_gitlink_ref_recursive() after it failed to read
 936 * from the loose refs in ref_cache refs. Find <refname> in the
 937 * packed-refs file for the submodule.
 938 */
 939static int resolve_gitlink_packed_ref(struct ref_cache *refs,
 940                                      const char *refname, unsigned char *sha1)
 941{
 942        struct ref_entry *ref;
 943        struct ref_dir *dir = get_packed_refs(refs);
 944
 945        ref = find_ref(dir, refname);
 946        if (ref == NULL)
 947                return -1;
 948
 949        memcpy(sha1, ref->u.value.sha1, 20);
 950        return 0;
 951}
 952
 953static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
 954                                         const char *refname, unsigned char *sha1,
 955                                         int recursion)
 956{
 957        int fd, len;
 958        char buffer[128], *p;
 959        char *path;
 960
 961        if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
 962                return -1;
 963        path = *refs->name
 964                ? git_path_submodule(refs->name, "%s", refname)
 965                : git_path("%s", refname);
 966        fd = open(path, O_RDONLY);
 967        if (fd < 0)
 968                return resolve_gitlink_packed_ref(refs, refname, sha1);
 969
 970        len = read(fd, buffer, sizeof(buffer)-1);
 971        close(fd);
 972        if (len < 0)
 973                return -1;
 974        while (len && isspace(buffer[len-1]))
 975                len--;
 976        buffer[len] = 0;
 977
 978        /* Was it a detached head or an old-fashioned symlink? */
 979        if (!get_sha1_hex(buffer, sha1))
 980                return 0;
 981
 982        /* Symref? */
 983        if (strncmp(buffer, "ref:", 4))
 984                return -1;
 985        p = buffer + 4;
 986        while (isspace(*p))
 987                p++;
 988
 989        return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
 990}
 991
 992int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
 993{
 994        int len = strlen(path), retval;
 995        char *submodule;
 996        struct ref_cache *refs;
 997
 998        while (len && path[len-1] == '/')
 999                len--;
1000        if (!len)
1001                return -1;
1002        submodule = xstrndup(path, len);
1003        refs = get_ref_cache(submodule);
1004        free(submodule);
1005
1006        retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1007        return retval;
1008}
1009
1010/*
1011 * Try to read ref from the packed references.  On success, set sha1
1012 * and return 0; otherwise, return -1.
1013 */
1014static int get_packed_ref(const char *refname, unsigned char *sha1)
1015{
1016        struct ref_dir *packed = get_packed_refs(get_ref_cache(NULL));
1017        struct ref_entry *entry = find_ref(packed, refname);
1018        if (entry) {
1019                hashcpy(sha1, entry->u.value.sha1);
1020                return 0;
1021        }
1022        return -1;
1023}
1024
1025const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int reading, int *flag)
1026{
1027        int depth = MAXDEPTH;
1028        ssize_t len;
1029        char buffer[256];
1030        static char refname_buffer[256];
1031
1032        if (flag)
1033                *flag = 0;
1034
1035        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
1036                return NULL;
1037
1038        for (;;) {
1039                char path[PATH_MAX];
1040                struct stat st;
1041                char *buf;
1042                int fd;
1043
1044                if (--depth < 0)
1045                        return NULL;
1046
1047                git_snpath(path, sizeof(path), "%s", refname);
1048
1049                if (lstat(path, &st) < 0) {
1050                        if (errno != ENOENT)
1051                                return NULL;
1052                        /*
1053                         * The loose reference file does not exist;
1054                         * check for a packed reference.
1055                         */
1056                        if (!get_packed_ref(refname, sha1)) {
1057                                if (flag)
1058                                        *flag |= REF_ISPACKED;
1059                                return refname;
1060                        }
1061                        /* The reference is not a packed reference, either. */
1062                        if (reading) {
1063                                return NULL;
1064                        } else {
1065                                hashclr(sha1);
1066                                return refname;
1067                        }
1068                }
1069
1070                /* Follow "normalized" - ie "refs/.." symlinks by hand */
1071                if (S_ISLNK(st.st_mode)) {
1072                        len = readlink(path, buffer, sizeof(buffer)-1);
1073                        if (len < 0)
1074                                return NULL;
1075                        buffer[len] = 0;
1076                        if (!prefixcmp(buffer, "refs/") &&
1077                                        !check_refname_format(buffer, 0)) {
1078                                strcpy(refname_buffer, buffer);
1079                                refname = refname_buffer;
1080                                if (flag)
1081                                        *flag |= REF_ISSYMREF;
1082                                continue;
1083                        }
1084                }
1085
1086                /* Is it a directory? */
1087                if (S_ISDIR(st.st_mode)) {
1088                        errno = EISDIR;
1089                        return NULL;
1090                }
1091
1092                /*
1093                 * Anything else, just open it and try to use it as
1094                 * a ref
1095                 */
1096                fd = open(path, O_RDONLY);
1097                if (fd < 0)
1098                        return NULL;
1099                len = read_in_full(fd, buffer, sizeof(buffer)-1);
1100                close(fd);
1101                if (len < 0)
1102                        return NULL;
1103                while (len && isspace(buffer[len-1]))
1104                        len--;
1105                buffer[len] = '\0';
1106
1107                /*
1108                 * Is it a symbolic ref?
1109                 */
1110                if (prefixcmp(buffer, "ref:"))
1111                        break;
1112                if (flag)
1113                        *flag |= REF_ISSYMREF;
1114                buf = buffer + 4;
1115                while (isspace(*buf))
1116                        buf++;
1117                if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1118                        if (flag)
1119                                *flag |= REF_ISBROKEN;
1120                        return NULL;
1121                }
1122                refname = strcpy(refname_buffer, buf);
1123        }
1124        /* Please note that FETCH_HEAD has a second line containing other data. */
1125        if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
1126                if (flag)
1127                        *flag |= REF_ISBROKEN;
1128                return NULL;
1129        }
1130        return refname;
1131}
1132
1133char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, int *flag)
1134{
1135        const char *ret = resolve_ref_unsafe(ref, sha1, reading, flag);
1136        return ret ? xstrdup(ret) : NULL;
1137}
1138
1139/* The argument to filter_refs */
1140struct ref_filter {
1141        const char *pattern;
1142        each_ref_fn *fn;
1143        void *cb_data;
1144};
1145
1146int read_ref_full(const char *refname, unsigned char *sha1, int reading, int *flags)
1147{
1148        if (resolve_ref_unsafe(refname, sha1, reading, flags))
1149                return 0;
1150        return -1;
1151}
1152
1153int read_ref(const char *refname, unsigned char *sha1)
1154{
1155        return read_ref_full(refname, sha1, 1, NULL);
1156}
1157
1158int ref_exists(const char *refname)
1159{
1160        unsigned char sha1[20];
1161        return !!resolve_ref_unsafe(refname, sha1, 1, NULL);
1162}
1163
1164static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
1165                       void *data)
1166{
1167        struct ref_filter *filter = (struct ref_filter *)data;
1168        if (fnmatch(filter->pattern, refname, 0))
1169                return 0;
1170        return filter->fn(refname, sha1, flags, filter->cb_data);
1171}
1172
1173int peel_ref(const char *refname, unsigned char *sha1)
1174{
1175        int flag;
1176        unsigned char base[20];
1177        struct object *o;
1178
1179        if (current_ref && (current_ref->name == refname
1180                || !strcmp(current_ref->name, refname))) {
1181                if (current_ref->flag & REF_KNOWS_PEELED) {
1182                        hashcpy(sha1, current_ref->u.value.peeled);
1183                        return 0;
1184                }
1185                hashcpy(base, current_ref->u.value.sha1);
1186                goto fallback;
1187        }
1188
1189        if (read_ref_full(refname, base, 1, &flag))
1190                return -1;
1191
1192        if ((flag & REF_ISPACKED)) {
1193                struct ref_dir *dir = get_packed_refs(get_ref_cache(NULL));
1194                struct ref_entry *r = find_ref(dir, refname);
1195
1196                if (r != NULL && r->flag & REF_KNOWS_PEELED) {
1197                        hashcpy(sha1, r->u.value.peeled);
1198                        return 0;
1199                }
1200        }
1201
1202fallback:
1203        o = parse_object(base);
1204        if (o && o->type == OBJ_TAG) {
1205                o = deref_tag(o, refname, 0);
1206                if (o) {
1207                        hashcpy(sha1, o->sha1);
1208                        return 0;
1209                }
1210        }
1211        return -1;
1212}
1213
1214struct warn_if_dangling_data {
1215        FILE *fp;
1216        const char *refname;
1217        const char *msg_fmt;
1218};
1219
1220static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
1221                                   int flags, void *cb_data)
1222{
1223        struct warn_if_dangling_data *d = cb_data;
1224        const char *resolves_to;
1225        unsigned char junk[20];
1226
1227        if (!(flags & REF_ISSYMREF))
1228                return 0;
1229
1230        resolves_to = resolve_ref_unsafe(refname, junk, 0, NULL);
1231        if (!resolves_to || strcmp(resolves_to, d->refname))
1232                return 0;
1233
1234        fprintf(d->fp, d->msg_fmt, refname);
1235        return 0;
1236}
1237
1238void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1239{
1240        struct warn_if_dangling_data data;
1241
1242        data.fp = fp;
1243        data.refname = refname;
1244        data.msg_fmt = msg_fmt;
1245        for_each_rawref(warn_if_dangling_symref, &data);
1246}
1247
1248static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
1249                           int trim, int flags, void *cb_data)
1250{
1251        struct ref_cache *refs = get_ref_cache(submodule);
1252        struct ref_dir *packed_dir = get_packed_refs(refs);
1253        struct ref_dir *loose_dir = get_loose_refs(refs);
1254        int retval = 0;
1255
1256        if (base && *base) {
1257                packed_dir = find_containing_dir(packed_dir, base, 0);
1258                loose_dir = find_containing_dir(loose_dir, base, 0);
1259        }
1260
1261        if (packed_dir && loose_dir) {
1262                sort_ref_dir(packed_dir);
1263                sort_ref_dir(loose_dir);
1264                retval = do_for_each_ref_in_dirs(
1265                                packed_dir, loose_dir,
1266                                base, fn, trim, flags, cb_data);
1267        } else if (packed_dir) {
1268                sort_ref_dir(packed_dir);
1269                retval = do_for_each_ref_in_dir(
1270                                packed_dir, 0,
1271                                base, fn, trim, flags, cb_data);
1272        } else if (loose_dir) {
1273                sort_ref_dir(loose_dir);
1274                retval = do_for_each_ref_in_dir(
1275                                loose_dir, 0,
1276                                base, fn, trim, flags, cb_data);
1277        }
1278
1279        return retval;
1280}
1281
1282static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1283{
1284        unsigned char sha1[20];
1285        int flag;
1286
1287        if (submodule) {
1288                if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
1289                        return fn("HEAD", sha1, 0, cb_data);
1290
1291                return 0;
1292        }
1293
1294        if (!read_ref_full("HEAD", sha1, 1, &flag))
1295                return fn("HEAD", sha1, flag, cb_data);
1296
1297        return 0;
1298}
1299
1300int head_ref(each_ref_fn fn, void *cb_data)
1301{
1302        return do_head_ref(NULL, fn, cb_data);
1303}
1304
1305int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1306{
1307        return do_head_ref(submodule, fn, cb_data);
1308}
1309
1310int for_each_ref(each_ref_fn fn, void *cb_data)
1311{
1312        return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
1313}
1314
1315int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1316{
1317        return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
1318}
1319
1320int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1321{
1322        return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
1323}
1324
1325int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1326                each_ref_fn fn, void *cb_data)
1327{
1328        return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
1329}
1330
1331int for_each_tag_ref(each_ref_fn fn, void *cb_data)
1332{
1333        return for_each_ref_in("refs/tags/", fn, cb_data);
1334}
1335
1336int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1337{
1338        return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
1339}
1340
1341int for_each_branch_ref(each_ref_fn fn, void *cb_data)
1342{
1343        return for_each_ref_in("refs/heads/", fn, cb_data);
1344}
1345
1346int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1347{
1348        return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
1349}
1350
1351int for_each_remote_ref(each_ref_fn fn, void *cb_data)
1352{
1353        return for_each_ref_in("refs/remotes/", fn, cb_data);
1354}
1355
1356int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1357{
1358        return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
1359}
1360
1361int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1362{
1363        return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
1364}
1365
1366int head_ref_namespaced(each_ref_fn fn, void *cb_data)
1367{
1368        struct strbuf buf = STRBUF_INIT;
1369        int ret = 0;
1370        unsigned char sha1[20];
1371        int flag;
1372
1373        strbuf_addf(&buf, "%sHEAD", get_git_namespace());
1374        if (!read_ref_full(buf.buf, sha1, 1, &flag))
1375                ret = fn(buf.buf, sha1, flag, cb_data);
1376        strbuf_release(&buf);
1377
1378        return ret;
1379}
1380
1381int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1382{
1383        struct strbuf buf = STRBUF_INIT;
1384        int ret;
1385        strbuf_addf(&buf, "%srefs/", get_git_namespace());
1386        ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
1387        strbuf_release(&buf);
1388        return ret;
1389}
1390
1391int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
1392        const char *prefix, void *cb_data)
1393{
1394        struct strbuf real_pattern = STRBUF_INIT;
1395        struct ref_filter filter;
1396        int ret;
1397
1398        if (!prefix && prefixcmp(pattern, "refs/"))
1399                strbuf_addstr(&real_pattern, "refs/");
1400        else if (prefix)
1401                strbuf_addstr(&real_pattern, prefix);
1402        strbuf_addstr(&real_pattern, pattern);
1403
1404        if (!has_glob_specials(pattern)) {
1405                /* Append implied '/' '*' if not present. */
1406                if (real_pattern.buf[real_pattern.len - 1] != '/')
1407                        strbuf_addch(&real_pattern, '/');
1408                /* No need to check for '*', there is none. */
1409                strbuf_addch(&real_pattern, '*');
1410        }
1411
1412        filter.pattern = real_pattern.buf;
1413        filter.fn = fn;
1414        filter.cb_data = cb_data;
1415        ret = for_each_ref(filter_refs, &filter);
1416
1417        strbuf_release(&real_pattern);
1418        return ret;
1419}
1420
1421int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
1422{
1423        return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
1424}
1425
1426int for_each_rawref(each_ref_fn fn, void *cb_data)
1427{
1428        return do_for_each_ref(NULL, "", fn, 0,
1429                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1430}
1431
1432const char *prettify_refname(const char *name)
1433{
1434        return name + (
1435                !prefixcmp(name, "refs/heads/") ? 11 :
1436                !prefixcmp(name, "refs/tags/") ? 10 :
1437                !prefixcmp(name, "refs/remotes/") ? 13 :
1438                0);
1439}
1440
1441const char *ref_rev_parse_rules[] = {
1442        "%.*s",
1443        "refs/%.*s",
1444        "refs/tags/%.*s",
1445        "refs/heads/%.*s",
1446        "refs/remotes/%.*s",
1447        "refs/remotes/%.*s/HEAD",
1448        NULL
1449};
1450
1451int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
1452{
1453        const char **p;
1454        const int abbrev_name_len = strlen(abbrev_name);
1455
1456        for (p = rules; *p; p++) {
1457                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1458                        return 1;
1459                }
1460        }
1461
1462        return 0;
1463}
1464
1465static struct ref_lock *verify_lock(struct ref_lock *lock,
1466        const unsigned char *old_sha1, int mustexist)
1467{
1468        if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1469                error("Can't verify ref %s", lock->ref_name);
1470                unlock_ref(lock);
1471                return NULL;
1472        }
1473        if (hashcmp(lock->old_sha1, old_sha1)) {
1474                error("Ref %s is at %s but expected %s", lock->ref_name,
1475                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1476                unlock_ref(lock);
1477                return NULL;
1478        }
1479        return lock;
1480}
1481
1482static int remove_empty_directories(const char *file)
1483{
1484        /* we want to create a file but there is a directory there;
1485         * if that is an empty directory (or a directory that contains
1486         * only empty directories), remove them.
1487         */
1488        struct strbuf path;
1489        int result;
1490
1491        strbuf_init(&path, 20);
1492        strbuf_addstr(&path, file);
1493
1494        result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1495
1496        strbuf_release(&path);
1497
1498        return result;
1499}
1500
1501/*
1502 * *string and *len will only be substituted, and *string returned (for
1503 * later free()ing) if the string passed in is a magic short-hand form
1504 * to name a branch.
1505 */
1506static char *substitute_branch_name(const char **string, int *len)
1507{
1508        struct strbuf buf = STRBUF_INIT;
1509        int ret = interpret_branch_name(*string, &buf);
1510
1511        if (ret == *len) {
1512                size_t size;
1513                *string = strbuf_detach(&buf, &size);
1514                *len = size;
1515                return (char *)*string;
1516        }
1517
1518        return NULL;
1519}
1520
1521int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
1522{
1523        char *last_branch = substitute_branch_name(&str, &len);
1524        const char **p, *r;
1525        int refs_found = 0;
1526
1527        *ref = NULL;
1528        for (p = ref_rev_parse_rules; *p; p++) {
1529                char fullref[PATH_MAX];
1530                unsigned char sha1_from_ref[20];
1531                unsigned char *this_result;
1532                int flag;
1533
1534                this_result = refs_found ? sha1_from_ref : sha1;
1535                mksnpath(fullref, sizeof(fullref), *p, len, str);
1536                r = resolve_ref_unsafe(fullref, this_result, 1, &flag);
1537                if (r) {
1538                        if (!refs_found++)
1539                                *ref = xstrdup(r);
1540                        if (!warn_ambiguous_refs)
1541                                break;
1542                } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
1543                        warning("ignoring dangling symref %s.", fullref);
1544                } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
1545                        warning("ignoring broken ref %s.", fullref);
1546                }
1547        }
1548        free(last_branch);
1549        return refs_found;
1550}
1551
1552int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
1553{
1554        char *last_branch = substitute_branch_name(&str, &len);
1555        const char **p;
1556        int logs_found = 0;
1557
1558        *log = NULL;
1559        for (p = ref_rev_parse_rules; *p; p++) {
1560                struct stat st;
1561                unsigned char hash[20];
1562                char path[PATH_MAX];
1563                const char *ref, *it;
1564
1565                mksnpath(path, sizeof(path), *p, len, str);
1566                ref = resolve_ref_unsafe(path, hash, 1, NULL);
1567                if (!ref)
1568                        continue;
1569                if (!stat(git_path("logs/%s", path), &st) &&
1570                    S_ISREG(st.st_mode))
1571                        it = path;
1572                else if (strcmp(ref, path) &&
1573                         !stat(git_path("logs/%s", ref), &st) &&
1574                         S_ISREG(st.st_mode))
1575                        it = ref;
1576                else
1577                        continue;
1578                if (!logs_found++) {
1579                        *log = xstrdup(it);
1580                        hashcpy(sha1, hash);
1581                }
1582                if (!warn_ambiguous_refs)
1583                        break;
1584        }
1585        free(last_branch);
1586        return logs_found;
1587}
1588
1589static struct ref_lock *lock_ref_sha1_basic(const char *refname,
1590                                            const unsigned char *old_sha1,
1591                                            int flags, int *type_p)
1592{
1593        char *ref_file;
1594        const char *orig_refname = refname;
1595        struct ref_lock *lock;
1596        int last_errno = 0;
1597        int type, lflags;
1598        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1599        int missing = 0;
1600
1601        lock = xcalloc(1, sizeof(struct ref_lock));
1602        lock->lock_fd = -1;
1603
1604        refname = resolve_ref_unsafe(refname, lock->old_sha1, mustexist, &type);
1605        if (!refname && errno == EISDIR) {
1606                /* we are trying to lock foo but we used to
1607                 * have foo/bar which now does not exist;
1608                 * it is normal for the empty directory 'foo'
1609                 * to remain.
1610                 */
1611                ref_file = git_path("%s", orig_refname);
1612                if (remove_empty_directories(ref_file)) {
1613                        last_errno = errno;
1614                        error("there are still refs under '%s'", orig_refname);
1615                        goto error_return;
1616                }
1617                refname = resolve_ref_unsafe(orig_refname, lock->old_sha1, mustexist, &type);
1618        }
1619        if (type_p)
1620            *type_p = type;
1621        if (!refname) {
1622                last_errno = errno;
1623                error("unable to resolve reference %s: %s",
1624                        orig_refname, strerror(errno));
1625                goto error_return;
1626        }
1627        missing = is_null_sha1(lock->old_sha1);
1628        /* When the ref did not exist and we are creating it,
1629         * make sure there is no existing ref that is packed
1630         * whose name begins with our refname, nor a ref whose
1631         * name is a proper prefix of our refname.
1632         */
1633        if (missing &&
1634             !is_refname_available(refname, NULL, get_packed_refs(get_ref_cache(NULL)))) {
1635                last_errno = ENOTDIR;
1636                goto error_return;
1637        }
1638
1639        lock->lk = xcalloc(1, sizeof(struct lock_file));
1640
1641        lflags = LOCK_DIE_ON_ERROR;
1642        if (flags & REF_NODEREF) {
1643                refname = orig_refname;
1644                lflags |= LOCK_NODEREF;
1645        }
1646        lock->ref_name = xstrdup(refname);
1647        lock->orig_ref_name = xstrdup(orig_refname);
1648        ref_file = git_path("%s", refname);
1649        if (missing)
1650                lock->force_write = 1;
1651        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1652                lock->force_write = 1;
1653
1654        if (safe_create_leading_directories(ref_file)) {
1655                last_errno = errno;
1656                error("unable to create directory for %s", ref_file);
1657                goto error_return;
1658        }
1659
1660        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1661        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1662
1663 error_return:
1664        unlock_ref(lock);
1665        errno = last_errno;
1666        return NULL;
1667}
1668
1669struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
1670{
1671        char refpath[PATH_MAX];
1672        if (check_refname_format(refname, 0))
1673                return NULL;
1674        strcpy(refpath, mkpath("refs/%s", refname));
1675        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1676}
1677
1678struct ref_lock *lock_any_ref_for_update(const char *refname,
1679                                         const unsigned char *old_sha1, int flags)
1680{
1681        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
1682                return NULL;
1683        return lock_ref_sha1_basic(refname, old_sha1, flags, NULL);
1684}
1685
1686struct repack_without_ref_sb {
1687        const char *refname;
1688        int fd;
1689};
1690
1691static int repack_without_ref_fn(const char *refname, const unsigned char *sha1,
1692                                 int flags, void *cb_data)
1693{
1694        struct repack_without_ref_sb *data = cb_data;
1695        char line[PATH_MAX + 100];
1696        int len;
1697
1698        if (!strcmp(data->refname, refname))
1699                return 0;
1700        len = snprintf(line, sizeof(line), "%s %s\n",
1701                       sha1_to_hex(sha1), refname);
1702        /* this should not happen but just being defensive */
1703        if (len > sizeof(line))
1704                die("too long a refname '%s'", refname);
1705        write_or_die(data->fd, line, len);
1706        return 0;
1707}
1708
1709static struct lock_file packlock;
1710
1711static int repack_without_ref(const char *refname)
1712{
1713        struct repack_without_ref_sb data;
1714        struct ref_dir *packed = get_packed_refs(get_ref_cache(NULL));
1715        if (find_ref(packed, refname) == NULL)
1716                return 0;
1717        data.refname = refname;
1718        data.fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1719        if (data.fd < 0) {
1720                unable_to_lock_error(git_path("packed-refs"), errno);
1721                return error("cannot delete '%s' from packed refs", refname);
1722        }
1723        do_for_each_ref_in_dir(packed, 0, "", repack_without_ref_fn, 0, 0, &data);
1724        return commit_lock_file(&packlock);
1725}
1726
1727int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1728{
1729        struct ref_lock *lock;
1730        int err, i = 0, ret = 0, flag = 0;
1731
1732        lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1733        if (!lock)
1734                return 1;
1735        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1736                /* loose */
1737                const char *path;
1738
1739                if (!(delopt & REF_NODEREF)) {
1740                        i = strlen(lock->lk->filename) - 5; /* .lock */
1741                        lock->lk->filename[i] = 0;
1742                        path = lock->lk->filename;
1743                } else {
1744                        path = git_path("%s", refname);
1745                }
1746                err = unlink_or_warn(path);
1747                if (err && errno != ENOENT)
1748                        ret = 1;
1749
1750                if (!(delopt & REF_NODEREF))
1751                        lock->lk->filename[i] = '.';
1752        }
1753        /* removing the loose one could have resurrected an earlier
1754         * packed one.  Also, if it was not loose we need to repack
1755         * without it.
1756         */
1757        ret |= repack_without_ref(refname);
1758
1759        unlink_or_warn(git_path("logs/%s", lock->ref_name));
1760        invalidate_ref_cache(NULL);
1761        unlock_ref(lock);
1762        return ret;
1763}
1764
1765/*
1766 * People using contrib's git-new-workdir have .git/logs/refs ->
1767 * /some/other/path/.git/logs/refs, and that may live on another device.
1768 *
1769 * IOW, to avoid cross device rename errors, the temporary renamed log must
1770 * live into logs/refs.
1771 */
1772#define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1773
1774int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
1775{
1776        unsigned char sha1[20], orig_sha1[20];
1777        int flag = 0, logmoved = 0;
1778        struct ref_lock *lock;
1779        struct stat loginfo;
1780        int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
1781        const char *symref = NULL;
1782        struct ref_cache *refs = get_ref_cache(NULL);
1783
1784        if (log && S_ISLNK(loginfo.st_mode))
1785                return error("reflog for %s is a symlink", oldrefname);
1786
1787        symref = resolve_ref_unsafe(oldrefname, orig_sha1, 1, &flag);
1788        if (flag & REF_ISSYMREF)
1789                return error("refname %s is a symbolic ref, renaming it is not supported",
1790                        oldrefname);
1791        if (!symref)
1792                return error("refname %s not found", oldrefname);
1793
1794        if (!is_refname_available(newrefname, oldrefname, get_packed_refs(refs)))
1795                return 1;
1796
1797        if (!is_refname_available(newrefname, oldrefname, get_loose_refs(refs)))
1798                return 1;
1799
1800        if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
1801                return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1802                        oldrefname, strerror(errno));
1803
1804        if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
1805                error("unable to delete old %s", oldrefname);
1806                goto rollback;
1807        }
1808
1809        if (!read_ref_full(newrefname, sha1, 1, &flag) &&
1810            delete_ref(newrefname, sha1, REF_NODEREF)) {
1811                if (errno==EISDIR) {
1812                        if (remove_empty_directories(git_path("%s", newrefname))) {
1813                                error("Directory not empty: %s", newrefname);
1814                                goto rollback;
1815                        }
1816                } else {
1817                        error("unable to delete existing %s", newrefname);
1818                        goto rollback;
1819                }
1820        }
1821
1822        if (log && safe_create_leading_directories(git_path("logs/%s", newrefname))) {
1823                error("unable to create directory for %s", newrefname);
1824                goto rollback;
1825        }
1826
1827 retry:
1828        if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
1829                if (errno==EISDIR || errno==ENOTDIR) {
1830                        /*
1831                         * rename(a, b) when b is an existing
1832                         * directory ought to result in ISDIR, but
1833                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1834                         */
1835                        if (remove_empty_directories(git_path("logs/%s", newrefname))) {
1836                                error("Directory not empty: logs/%s", newrefname);
1837                                goto rollback;
1838                        }
1839                        goto retry;
1840                } else {
1841                        error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1842                                newrefname, strerror(errno));
1843                        goto rollback;
1844                }
1845        }
1846        logmoved = log;
1847
1848        lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
1849        if (!lock) {
1850                error("unable to lock %s for update", newrefname);
1851                goto rollback;
1852        }
1853        lock->force_write = 1;
1854        hashcpy(lock->old_sha1, orig_sha1);
1855        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1856                error("unable to write current sha1 into %s", newrefname);
1857                goto rollback;
1858        }
1859
1860        return 0;
1861
1862 rollback:
1863        lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
1864        if (!lock) {
1865                error("unable to lock %s for rollback", oldrefname);
1866                goto rollbacklog;
1867        }
1868
1869        lock->force_write = 1;
1870        flag = log_all_ref_updates;
1871        log_all_ref_updates = 0;
1872        if (write_ref_sha1(lock, orig_sha1, NULL))
1873                error("unable to write current sha1 into %s", oldrefname);
1874        log_all_ref_updates = flag;
1875
1876 rollbacklog:
1877        if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
1878                error("unable to restore logfile %s from %s: %s",
1879                        oldrefname, newrefname, strerror(errno));
1880        if (!logmoved && log &&
1881            rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
1882                error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1883                        oldrefname, strerror(errno));
1884
1885        return 1;
1886}
1887
1888int close_ref(struct ref_lock *lock)
1889{
1890        if (close_lock_file(lock->lk))
1891                return -1;
1892        lock->lock_fd = -1;
1893        return 0;
1894}
1895
1896int commit_ref(struct ref_lock *lock)
1897{
1898        if (commit_lock_file(lock->lk))
1899                return -1;
1900        lock->lock_fd = -1;
1901        return 0;
1902}
1903
1904void unlock_ref(struct ref_lock *lock)
1905{
1906        /* Do not free lock->lk -- atexit() still looks at them */
1907        if (lock->lk)
1908                rollback_lock_file(lock->lk);
1909        free(lock->ref_name);
1910        free(lock->orig_ref_name);
1911        free(lock);
1912}
1913
1914/*
1915 * copy the reflog message msg to buf, which has been allocated sufficiently
1916 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1917 * because reflog file is one line per entry.
1918 */
1919static int copy_msg(char *buf, const char *msg)
1920{
1921        char *cp = buf;
1922        char c;
1923        int wasspace = 1;
1924
1925        *cp++ = '\t';
1926        while ((c = *msg++)) {
1927                if (wasspace && isspace(c))
1928                        continue;
1929                wasspace = isspace(c);
1930                if (wasspace)
1931                        c = ' ';
1932                *cp++ = c;
1933        }
1934        while (buf < cp && isspace(cp[-1]))
1935                cp--;
1936        *cp++ = '\n';
1937        return cp - buf;
1938}
1939
1940int log_ref_setup(const char *refname, char *logfile, int bufsize)
1941{
1942        int logfd, oflags = O_APPEND | O_WRONLY;
1943
1944        git_snpath(logfile, bufsize, "logs/%s", refname);
1945        if (log_all_ref_updates &&
1946            (!prefixcmp(refname, "refs/heads/") ||
1947             !prefixcmp(refname, "refs/remotes/") ||
1948             !prefixcmp(refname, "refs/notes/") ||
1949             !strcmp(refname, "HEAD"))) {
1950                if (safe_create_leading_directories(logfile) < 0)
1951                        return error("unable to create directory for %s",
1952                                     logfile);
1953                oflags |= O_CREAT;
1954        }
1955
1956        logfd = open(logfile, oflags, 0666);
1957        if (logfd < 0) {
1958                if (!(oflags & O_CREAT) && errno == ENOENT)
1959                        return 0;
1960
1961                if ((oflags & O_CREAT) && errno == EISDIR) {
1962                        if (remove_empty_directories(logfile)) {
1963                                return error("There are still logs under '%s'",
1964                                             logfile);
1965                        }
1966                        logfd = open(logfile, oflags, 0666);
1967                }
1968
1969                if (logfd < 0)
1970                        return error("Unable to append to %s: %s",
1971                                     logfile, strerror(errno));
1972        }
1973
1974        adjust_shared_perm(logfile);
1975        close(logfd);
1976        return 0;
1977}
1978
1979static int log_ref_write(const char *refname, const unsigned char *old_sha1,
1980                         const unsigned char *new_sha1, const char *msg)
1981{
1982        int logfd, result, written, oflags = O_APPEND | O_WRONLY;
1983        unsigned maxlen, len;
1984        int msglen;
1985        char log_file[PATH_MAX];
1986        char *logrec;
1987        const char *committer;
1988
1989        if (log_all_ref_updates < 0)
1990                log_all_ref_updates = !is_bare_repository();
1991
1992        result = log_ref_setup(refname, log_file, sizeof(log_file));
1993        if (result)
1994                return result;
1995
1996        logfd = open(log_file, oflags);
1997        if (logfd < 0)
1998                return 0;
1999        msglen = msg ? strlen(msg) : 0;
2000        committer = git_committer_info(0);
2001        maxlen = strlen(committer) + msglen + 100;
2002        logrec = xmalloc(maxlen);
2003        len = sprintf(logrec, "%s %s %s\n",
2004                      sha1_to_hex(old_sha1),
2005                      sha1_to_hex(new_sha1),
2006                      committer);
2007        if (msglen)
2008                len += copy_msg(logrec + len - 1, msg) - 1;
2009        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
2010        free(logrec);
2011        if (close(logfd) != 0 || written != len)
2012                return error("Unable to append to %s", log_file);
2013        return 0;
2014}
2015
2016static int is_branch(const char *refname)
2017{
2018        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
2019}
2020
2021int write_ref_sha1(struct ref_lock *lock,
2022        const unsigned char *sha1, const char *logmsg)
2023{
2024        static char term = '\n';
2025        struct object *o;
2026
2027        if (!lock)
2028                return -1;
2029        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
2030                unlock_ref(lock);
2031                return 0;
2032        }
2033        o = parse_object(sha1);
2034        if (!o) {
2035                error("Trying to write ref %s with nonexistent object %s",
2036                        lock->ref_name, sha1_to_hex(sha1));
2037                unlock_ref(lock);
2038                return -1;
2039        }
2040        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2041                error("Trying to write non-commit object %s to branch %s",
2042                        sha1_to_hex(sha1), lock->ref_name);
2043                unlock_ref(lock);
2044                return -1;
2045        }
2046        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
2047            write_in_full(lock->lock_fd, &term, 1) != 1
2048                || close_ref(lock) < 0) {
2049                error("Couldn't write %s", lock->lk->filename);
2050                unlock_ref(lock);
2051                return -1;
2052        }
2053        clear_loose_ref_cache(get_ref_cache(NULL));
2054        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
2055            (strcmp(lock->ref_name, lock->orig_ref_name) &&
2056             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
2057                unlock_ref(lock);
2058                return -1;
2059        }
2060        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
2061                /*
2062                 * Special hack: If a branch is updated directly and HEAD
2063                 * points to it (may happen on the remote side of a push
2064                 * for example) then logically the HEAD reflog should be
2065                 * updated too.
2066                 * A generic solution implies reverse symref information,
2067                 * but finding all symrefs pointing to the given branch
2068                 * would be rather costly for this rare event (the direct
2069                 * update of a branch) to be worth it.  So let's cheat and
2070                 * check with HEAD only which should cover 99% of all usage
2071                 * scenarios (even 100% of the default ones).
2072                 */
2073                unsigned char head_sha1[20];
2074                int head_flag;
2075                const char *head_ref;
2076                head_ref = resolve_ref_unsafe("HEAD", head_sha1, 1, &head_flag);
2077                if (head_ref && (head_flag & REF_ISSYMREF) &&
2078                    !strcmp(head_ref, lock->ref_name))
2079                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
2080        }
2081        if (commit_ref(lock)) {
2082                error("Couldn't set %s", lock->ref_name);
2083                unlock_ref(lock);
2084                return -1;
2085        }
2086        unlock_ref(lock);
2087        return 0;
2088}
2089
2090int create_symref(const char *ref_target, const char *refs_heads_master,
2091                  const char *logmsg)
2092{
2093        const char *lockpath;
2094        char ref[1000];
2095        int fd, len, written;
2096        char *git_HEAD = git_pathdup("%s", ref_target);
2097        unsigned char old_sha1[20], new_sha1[20];
2098
2099        if (logmsg && read_ref(ref_target, old_sha1))
2100                hashclr(old_sha1);
2101
2102        if (safe_create_leading_directories(git_HEAD) < 0)
2103                return error("unable to create directory for %s", git_HEAD);
2104
2105#ifndef NO_SYMLINK_HEAD
2106        if (prefer_symlink_refs) {
2107                unlink(git_HEAD);
2108                if (!symlink(refs_heads_master, git_HEAD))
2109                        goto done;
2110                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
2111        }
2112#endif
2113
2114        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
2115        if (sizeof(ref) <= len) {
2116                error("refname too long: %s", refs_heads_master);
2117                goto error_free_return;
2118        }
2119        lockpath = mkpath("%s.lock", git_HEAD);
2120        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
2121        if (fd < 0) {
2122                error("Unable to open %s for writing", lockpath);
2123                goto error_free_return;
2124        }
2125        written = write_in_full(fd, ref, len);
2126        if (close(fd) != 0 || written != len) {
2127                error("Unable to write to %s", lockpath);
2128                goto error_unlink_return;
2129        }
2130        if (rename(lockpath, git_HEAD) < 0) {
2131                error("Unable to create %s", git_HEAD);
2132                goto error_unlink_return;
2133        }
2134        if (adjust_shared_perm(git_HEAD)) {
2135                error("Unable to fix permissions on %s", lockpath);
2136        error_unlink_return:
2137                unlink_or_warn(lockpath);
2138        error_free_return:
2139                free(git_HEAD);
2140                return -1;
2141        }
2142
2143#ifndef NO_SYMLINK_HEAD
2144        done:
2145#endif
2146        if (logmsg && !read_ref(refs_heads_master, new_sha1))
2147                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
2148
2149        free(git_HEAD);
2150        return 0;
2151}
2152
2153static char *ref_msg(const char *line, const char *endp)
2154{
2155        const char *ep;
2156        line += 82;
2157        ep = memchr(line, '\n', endp - line);
2158        if (!ep)
2159                ep = endp;
2160        return xmemdupz(line, ep - line);
2161}
2162
2163int read_ref_at(const char *refname, unsigned long at_time, int cnt,
2164                unsigned char *sha1, char **msg,
2165                unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
2166{
2167        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
2168        char *tz_c;
2169        int logfd, tz, reccnt = 0;
2170        struct stat st;
2171        unsigned long date;
2172        unsigned char logged_sha1[20];
2173        void *log_mapped;
2174        size_t mapsz;
2175
2176        logfile = git_path("logs/%s", refname);
2177        logfd = open(logfile, O_RDONLY, 0);
2178        if (logfd < 0)
2179                die_errno("Unable to read log '%s'", logfile);
2180        fstat(logfd, &st);
2181        if (!st.st_size)
2182                die("Log %s is empty.", logfile);
2183        mapsz = xsize_t(st.st_size);
2184        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
2185        logdata = log_mapped;
2186        close(logfd);
2187
2188        lastrec = NULL;
2189        rec = logend = logdata + st.st_size;
2190        while (logdata < rec) {
2191                reccnt++;
2192                if (logdata < rec && *(rec-1) == '\n')
2193                        rec--;
2194                lastgt = NULL;
2195                while (logdata < rec && *(rec-1) != '\n') {
2196                        rec--;
2197                        if (*rec == '>')
2198                                lastgt = rec;
2199                }
2200                if (!lastgt)
2201                        die("Log %s is corrupt.", logfile);
2202                date = strtoul(lastgt + 1, &tz_c, 10);
2203                if (date <= at_time || cnt == 0) {
2204                        tz = strtoul(tz_c, NULL, 10);
2205                        if (msg)
2206                                *msg = ref_msg(rec, logend);
2207                        if (cutoff_time)
2208                                *cutoff_time = date;
2209                        if (cutoff_tz)
2210                                *cutoff_tz = tz;
2211                        if (cutoff_cnt)
2212                                *cutoff_cnt = reccnt - 1;
2213                        if (lastrec) {
2214                                if (get_sha1_hex(lastrec, logged_sha1))
2215                                        die("Log %s is corrupt.", logfile);
2216                                if (get_sha1_hex(rec + 41, sha1))
2217                                        die("Log %s is corrupt.", logfile);
2218                                if (hashcmp(logged_sha1, sha1)) {
2219                                        warning("Log %s has gap after %s.",
2220                                                logfile, show_date(date, tz, DATE_RFC2822));
2221                                }
2222                        }
2223                        else if (date == at_time) {
2224                                if (get_sha1_hex(rec + 41, sha1))
2225                                        die("Log %s is corrupt.", logfile);
2226                        }
2227                        else {
2228                                if (get_sha1_hex(rec + 41, logged_sha1))
2229                                        die("Log %s is corrupt.", logfile);
2230                                if (hashcmp(logged_sha1, sha1)) {
2231                                        warning("Log %s unexpectedly ended on %s.",
2232                                                logfile, show_date(date, tz, DATE_RFC2822));
2233                                }
2234                        }
2235                        munmap(log_mapped, mapsz);
2236                        return 0;
2237                }
2238                lastrec = rec;
2239                if (cnt > 0)
2240                        cnt--;
2241        }
2242
2243        rec = logdata;
2244        while (rec < logend && *rec != '>' && *rec != '\n')
2245                rec++;
2246        if (rec == logend || *rec == '\n')
2247                die("Log %s is corrupt.", logfile);
2248        date = strtoul(rec + 1, &tz_c, 10);
2249        tz = strtoul(tz_c, NULL, 10);
2250        if (get_sha1_hex(logdata, sha1))
2251                die("Log %s is corrupt.", logfile);
2252        if (is_null_sha1(sha1)) {
2253                if (get_sha1_hex(logdata + 41, sha1))
2254                        die("Log %s is corrupt.", logfile);
2255        }
2256        if (msg)
2257                *msg = ref_msg(logdata, logend);
2258        munmap(log_mapped, mapsz);
2259
2260        if (cutoff_time)
2261                *cutoff_time = date;
2262        if (cutoff_tz)
2263                *cutoff_tz = tz;
2264        if (cutoff_cnt)
2265                *cutoff_cnt = reccnt;
2266        return 1;
2267}
2268
2269int for_each_recent_reflog_ent(const char *refname, each_reflog_ent_fn fn, long ofs, void *cb_data)
2270{
2271        const char *logfile;
2272        FILE *logfp;
2273        struct strbuf sb = STRBUF_INIT;
2274        int ret = 0;
2275
2276        logfile = git_path("logs/%s", refname);
2277        logfp = fopen(logfile, "r");
2278        if (!logfp)
2279                return -1;
2280
2281        if (ofs) {
2282                struct stat statbuf;
2283                if (fstat(fileno(logfp), &statbuf) ||
2284                    statbuf.st_size < ofs ||
2285                    fseek(logfp, -ofs, SEEK_END) ||
2286                    strbuf_getwholeline(&sb, logfp, '\n')) {
2287                        fclose(logfp);
2288                        strbuf_release(&sb);
2289                        return -1;
2290                }
2291        }
2292
2293        while (!strbuf_getwholeline(&sb, logfp, '\n')) {
2294                unsigned char osha1[20], nsha1[20];
2295                char *email_end, *message;
2296                unsigned long timestamp;
2297                int tz;
2298
2299                /* old SP new SP name <email> SP time TAB msg LF */
2300                if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
2301                    get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
2302                    get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
2303                    !(email_end = strchr(sb.buf + 82, '>')) ||
2304                    email_end[1] != ' ' ||
2305                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
2306                    !message || message[0] != ' ' ||
2307                    (message[1] != '+' && message[1] != '-') ||
2308                    !isdigit(message[2]) || !isdigit(message[3]) ||
2309                    !isdigit(message[4]) || !isdigit(message[5]))
2310                        continue; /* corrupt? */
2311                email_end[1] = '\0';
2312                tz = strtol(message + 1, NULL, 10);
2313                if (message[6] != '\t')
2314                        message += 6;
2315                else
2316                        message += 7;
2317                ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
2318                         cb_data);
2319                if (ret)
2320                        break;
2321        }
2322        fclose(logfp);
2323        strbuf_release(&sb);
2324        return ret;
2325}
2326
2327int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
2328{
2329        return for_each_recent_reflog_ent(refname, fn, 0, cb_data);
2330}
2331
2332/*
2333 * Call fn for each reflog in the namespace indicated by name.  name
2334 * must be empty or end with '/'.  Name will be used as a scratch
2335 * space, but its contents will be restored before return.
2336 */
2337static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
2338{
2339        DIR *d = opendir(git_path("logs/%s", name->buf));
2340        int retval = 0;
2341        struct dirent *de;
2342        int oldlen = name->len;
2343
2344        if (!d)
2345                return name->len ? errno : 0;
2346
2347        while ((de = readdir(d)) != NULL) {
2348                struct stat st;
2349
2350                if (de->d_name[0] == '.')
2351                        continue;
2352                if (has_extension(de->d_name, ".lock"))
2353                        continue;
2354                strbuf_addstr(name, de->d_name);
2355                if (stat(git_path("logs/%s", name->buf), &st) < 0) {
2356                        ; /* silently ignore */
2357                } else {
2358                        if (S_ISDIR(st.st_mode)) {
2359                                strbuf_addch(name, '/');
2360                                retval = do_for_each_reflog(name, fn, cb_data);
2361                        } else {
2362                                unsigned char sha1[20];
2363                                if (read_ref_full(name->buf, sha1, 0, NULL))
2364                                        retval = error("bad ref for %s", name->buf);
2365                                else
2366                                        retval = fn(name->buf, sha1, 0, cb_data);
2367                        }
2368                        if (retval)
2369                                break;
2370                }
2371                strbuf_setlen(name, oldlen);
2372        }
2373        closedir(d);
2374        return retval;
2375}
2376
2377int for_each_reflog(each_ref_fn fn, void *cb_data)
2378{
2379        int retval;
2380        struct strbuf name;
2381        strbuf_init(&name, PATH_MAX);
2382        retval = do_for_each_reflog(&name, fn, cb_data);
2383        strbuf_release(&name);
2384        return retval;
2385}
2386
2387int update_ref(const char *action, const char *refname,
2388                const unsigned char *sha1, const unsigned char *oldval,
2389                int flags, enum action_on_err onerr)
2390{
2391        static struct ref_lock *lock;
2392        lock = lock_any_ref_for_update(refname, oldval, flags);
2393        if (!lock) {
2394                const char *str = "Cannot lock the ref '%s'.";
2395                switch (onerr) {
2396                case MSG_ON_ERR: error(str, refname); break;
2397                case DIE_ON_ERR: die(str, refname); break;
2398                case QUIET_ON_ERR: break;
2399                }
2400                return 1;
2401        }
2402        if (write_ref_sha1(lock, sha1, action) < 0) {
2403                const char *str = "Cannot update the ref '%s'.";
2404                switch (onerr) {
2405                case MSG_ON_ERR: error(str, refname); break;
2406                case DIE_ON_ERR: die(str, refname); break;
2407                case QUIET_ON_ERR: break;
2408                }
2409                return 1;
2410        }
2411        return 0;
2412}
2413
2414struct ref *find_ref_by_name(const struct ref *list, const char *name)
2415{
2416        for ( ; list; list = list->next)
2417                if (!strcmp(list->name, name))
2418                        return (struct ref *)list;
2419        return NULL;
2420}
2421
2422/*
2423 * generate a format suitable for scanf from a ref_rev_parse_rules
2424 * rule, that is replace the "%.*s" spec with a "%s" spec
2425 */
2426static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
2427{
2428        char *spec;
2429
2430        spec = strstr(rule, "%.*s");
2431        if (!spec || strstr(spec + 4, "%.*s"))
2432                die("invalid rule in ref_rev_parse_rules: %s", rule);
2433
2434        /* copy all until spec */
2435        strncpy(scanf_fmt, rule, spec - rule);
2436        scanf_fmt[spec - rule] = '\0';
2437        /* copy new spec */
2438        strcat(scanf_fmt, "%s");
2439        /* copy remaining rule */
2440        strcat(scanf_fmt, spec + 4);
2441
2442        return;
2443}
2444
2445char *shorten_unambiguous_ref(const char *refname, int strict)
2446{
2447        int i;
2448        static char **scanf_fmts;
2449        static int nr_rules;
2450        char *short_name;
2451
2452        /* pre generate scanf formats from ref_rev_parse_rules[] */
2453        if (!nr_rules) {
2454                size_t total_len = 0;
2455
2456                /* the rule list is NULL terminated, count them first */
2457                for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
2458                        /* no +1 because strlen("%s") < strlen("%.*s") */
2459                        total_len += strlen(ref_rev_parse_rules[nr_rules]);
2460
2461                scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
2462
2463                total_len = 0;
2464                for (i = 0; i < nr_rules; i++) {
2465                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
2466                                        + total_len;
2467                        gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
2468                        total_len += strlen(ref_rev_parse_rules[i]);
2469                }
2470        }
2471
2472        /* bail out if there are no rules */
2473        if (!nr_rules)
2474                return xstrdup(refname);
2475
2476        /* buffer for scanf result, at most refname must fit */
2477        short_name = xstrdup(refname);
2478
2479        /* skip first rule, it will always match */
2480        for (i = nr_rules - 1; i > 0 ; --i) {
2481                int j;
2482                int rules_to_fail = i;
2483                int short_name_len;
2484
2485                if (1 != sscanf(refname, scanf_fmts[i], short_name))
2486                        continue;
2487
2488                short_name_len = strlen(short_name);
2489
2490                /*
2491                 * in strict mode, all (except the matched one) rules
2492                 * must fail to resolve to a valid non-ambiguous ref
2493                 */
2494                if (strict)
2495                        rules_to_fail = nr_rules;
2496
2497                /*
2498                 * check if the short name resolves to a valid ref,
2499                 * but use only rules prior to the matched one
2500                 */
2501                for (j = 0; j < rules_to_fail; j++) {
2502                        const char *rule = ref_rev_parse_rules[j];
2503                        char refname[PATH_MAX];
2504
2505                        /* skip matched rule */
2506                        if (i == j)
2507                                continue;
2508
2509                        /*
2510                         * the short name is ambiguous, if it resolves
2511                         * (with this previous rule) to a valid ref
2512                         * read_ref() returns 0 on success
2513                         */
2514                        mksnpath(refname, sizeof(refname),
2515                                 rule, short_name_len, short_name);
2516                        if (ref_exists(refname))
2517                                break;
2518                }
2519
2520                /*
2521                 * short name is non-ambiguous if all previous rules
2522                 * haven't resolved to a valid ref
2523                 */
2524                if (j == rules_to_fail)
2525                        return short_name;
2526        }
2527
2528        free(short_name);
2529        return xstrdup(refname);
2530}