refs.con commit Merge branch 'jc/maint-t7406-rev-parse-max-count-huh' into maint-1.7.11 (ffb1346)
   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                /*
 264                 * Do not use get_ref_dir() here, as that might
 265                 * trigger the reading of loose refs.
 266                 */
 267                clear_ref_dir(&entry->u.subdir);
 268        }
 269        free(entry);
 270}
 271
 272/*
 273 * Add a ref_entry to the end of dir (unsorted).  Entry is always
 274 * stored directly in dir; no recursion into subdirectories is
 275 * done.
 276 */
 277static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
 278{
 279        ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
 280        dir->entries[dir->nr++] = entry;
 281        /* optimize for the case that entries are added in order */
 282        if (dir->nr == 1 ||
 283            (dir->nr == dir->sorted + 1 &&
 284             strcmp(dir->entries[dir->nr - 2]->name,
 285                    dir->entries[dir->nr - 1]->name) < 0))
 286                dir->sorted = dir->nr;
 287}
 288
 289/*
 290 * Clear and free all entries in dir, recursively.
 291 */
 292static void clear_ref_dir(struct ref_dir *dir)
 293{
 294        int i;
 295        for (i = 0; i < dir->nr; i++)
 296                free_ref_entry(dir->entries[i]);
 297        free(dir->entries);
 298        dir->sorted = dir->nr = dir->alloc = 0;
 299        dir->entries = NULL;
 300}
 301
 302/*
 303 * Create a struct ref_entry object for the specified dirname.
 304 * dirname is the name of the directory with a trailing slash (e.g.,
 305 * "refs/heads/") or "" for the top-level directory.
 306 */
 307static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
 308                                          const char *dirname, size_t len,
 309                                          int incomplete)
 310{
 311        struct ref_entry *direntry;
 312        direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
 313        memcpy(direntry->name, dirname, len);
 314        direntry->name[len] = '\0';
 315        direntry->u.subdir.ref_cache = ref_cache;
 316        direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
 317        return direntry;
 318}
 319
 320static int ref_entry_cmp(const void *a, const void *b)
 321{
 322        struct ref_entry *one = *(struct ref_entry **)a;
 323        struct ref_entry *two = *(struct ref_entry **)b;
 324        return strcmp(one->name, two->name);
 325}
 326
 327static void sort_ref_dir(struct ref_dir *dir);
 328
 329struct string_slice {
 330        size_t len;
 331        const char *str;
 332};
 333
 334static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
 335{
 336        struct string_slice *key = (struct string_slice *)key_;
 337        struct ref_entry *ent = *(struct ref_entry **)ent_;
 338        int entlen = strlen(ent->name);
 339        int cmplen = key->len < entlen ? key->len : entlen;
 340        int cmp = memcmp(key->str, ent->name, cmplen);
 341        if (cmp)
 342                return cmp;
 343        return key->len - entlen;
 344}
 345
 346/*
 347 * Return the entry with the given refname from the ref_dir
 348 * (non-recursively), sorting dir if necessary.  Return NULL if no
 349 * such entry is found.  dir must already be complete.
 350 */
 351static struct ref_entry *search_ref_dir(struct ref_dir *dir,
 352                                        const char *refname, size_t len)
 353{
 354        struct ref_entry **r;
 355        struct string_slice key;
 356
 357        if (refname == NULL || !dir->nr)
 358                return NULL;
 359
 360        sort_ref_dir(dir);
 361        key.len = len;
 362        key.str = refname;
 363        r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
 364                    ref_entry_cmp_sslice);
 365
 366        if (r == NULL)
 367                return NULL;
 368
 369        return *r;
 370}
 371
 372/*
 373 * Search for a directory entry directly within dir (without
 374 * recursing).  Sort dir if necessary.  subdirname must be a directory
 375 * name (i.e., end in '/').  If mkdir is set, then create the
 376 * directory if it is missing; otherwise, return NULL if the desired
 377 * directory cannot be found.  dir must already be complete.
 378 */
 379static struct ref_dir *search_for_subdir(struct ref_dir *dir,
 380                                         const char *subdirname, size_t len,
 381                                         int mkdir)
 382{
 383        struct ref_entry *entry = search_ref_dir(dir, subdirname, len);
 384        if (!entry) {
 385                if (!mkdir)
 386                        return NULL;
 387                /*
 388                 * Since dir is complete, the absence of a subdir
 389                 * means that the subdir really doesn't exist;
 390                 * therefore, create an empty record for it but mark
 391                 * the record complete.
 392                 */
 393                entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
 394                add_entry_to_dir(dir, entry);
 395        }
 396        return get_ref_dir(entry);
 397}
 398
 399/*
 400 * If refname is a reference name, find the ref_dir within the dir
 401 * tree that should hold refname.  If refname is a directory name
 402 * (i.e., ends in '/'), then return that ref_dir itself.  dir must
 403 * represent the top-level directory and must already be complete.
 404 * Sort ref_dirs and recurse into subdirectories as necessary.  If
 405 * mkdir is set, then create any missing directories; otherwise,
 406 * return NULL if the desired directory cannot be found.
 407 */
 408static struct ref_dir *find_containing_dir(struct ref_dir *dir,
 409                                           const char *refname, int mkdir)
 410{
 411        const char *slash;
 412        for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
 413                size_t dirnamelen = slash - refname + 1;
 414                struct ref_dir *subdir;
 415                subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
 416                if (!subdir) {
 417                        dir = NULL;
 418                        break;
 419                }
 420                dir = subdir;
 421        }
 422
 423        return dir;
 424}
 425
 426/*
 427 * Find the value entry with the given name in dir, sorting ref_dirs
 428 * and recursing into subdirectories as necessary.  If the name is not
 429 * found or it corresponds to a directory entry, return NULL.
 430 */
 431static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
 432{
 433        struct ref_entry *entry;
 434        dir = find_containing_dir(dir, refname, 0);
 435        if (!dir)
 436                return NULL;
 437        entry = search_ref_dir(dir, refname, strlen(refname));
 438        return (entry && !(entry->flag & REF_DIR)) ? entry : NULL;
 439}
 440
 441/*
 442 * Add a ref_entry to the ref_dir (unsorted), recursing into
 443 * subdirectories as necessary.  dir must represent the top-level
 444 * directory.  Return 0 on success.
 445 */
 446static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
 447{
 448        dir = find_containing_dir(dir, ref->name, 1);
 449        if (!dir)
 450                return -1;
 451        add_entry_to_dir(dir, ref);
 452        return 0;
 453}
 454
 455/*
 456 * Emit a warning and return true iff ref1 and ref2 have the same name
 457 * and the same sha1.  Die if they have the same name but different
 458 * sha1s.
 459 */
 460static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
 461{
 462        if (strcmp(ref1->name, ref2->name))
 463                return 0;
 464
 465        /* Duplicate name; make sure that they don't conflict: */
 466
 467        if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
 468                /* This is impossible by construction */
 469                die("Reference directory conflict: %s", ref1->name);
 470
 471        if (hashcmp(ref1->u.value.sha1, ref2->u.value.sha1))
 472                die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
 473
 474        warning("Duplicated ref: %s", ref1->name);
 475        return 1;
 476}
 477
 478/*
 479 * Sort the entries in dir non-recursively (if they are not already
 480 * sorted) and remove any duplicate entries.
 481 */
 482static void sort_ref_dir(struct ref_dir *dir)
 483{
 484        int i, j;
 485        struct ref_entry *last = NULL;
 486
 487        /*
 488         * This check also prevents passing a zero-length array to qsort(),
 489         * which is a problem on some platforms.
 490         */
 491        if (dir->sorted == dir->nr)
 492                return;
 493
 494        qsort(dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
 495
 496        /* Remove any duplicates: */
 497        for (i = 0, j = 0; j < dir->nr; j++) {
 498                struct ref_entry *entry = dir->entries[j];
 499                if (last && is_dup_ref(last, entry))
 500                        free_ref_entry(entry);
 501                else
 502                        last = dir->entries[i++] = entry;
 503        }
 504        dir->sorted = dir->nr = i;
 505}
 506
 507#define DO_FOR_EACH_INCLUDE_BROKEN 01
 508
 509static struct ref_entry *current_ref;
 510
 511static int do_one_ref(const char *base, each_ref_fn fn, int trim,
 512                      int flags, void *cb_data, struct ref_entry *entry)
 513{
 514        int retval;
 515        if (prefixcmp(entry->name, base))
 516                return 0;
 517
 518        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
 519                if (entry->flag & REF_ISBROKEN)
 520                        return 0; /* ignore broken refs e.g. dangling symref */
 521                if (!has_sha1_file(entry->u.value.sha1)) {
 522                        error("%s does not point to a valid object!", entry->name);
 523                        return 0;
 524                }
 525        }
 526        current_ref = entry;
 527        retval = fn(entry->name + trim, entry->u.value.sha1, entry->flag, cb_data);
 528        current_ref = NULL;
 529        return retval;
 530}
 531
 532/*
 533 * Call fn for each reference in dir that has index in the range
 534 * offset <= index < dir->nr.  Recurse into subdirectories that are in
 535 * that index range, sorting them before iterating.  This function
 536 * does not sort dir itself; it should be sorted beforehand.
 537 */
 538static int do_for_each_ref_in_dir(struct ref_dir *dir, int offset,
 539                                  const char *base,
 540                                  each_ref_fn fn, int trim, int flags, void *cb_data)
 541{
 542        int i;
 543        assert(dir->sorted == dir->nr);
 544        for (i = offset; i < dir->nr; i++) {
 545                struct ref_entry *entry = dir->entries[i];
 546                int retval;
 547                if (entry->flag & REF_DIR) {
 548                        struct ref_dir *subdir = get_ref_dir(entry);
 549                        sort_ref_dir(subdir);
 550                        retval = do_for_each_ref_in_dir(subdir, 0,
 551                                                        base, fn, trim, flags, cb_data);
 552                } else {
 553                        retval = do_one_ref(base, fn, trim, flags, cb_data, entry);
 554                }
 555                if (retval)
 556                        return retval;
 557        }
 558        return 0;
 559}
 560
 561/*
 562 * Call fn for each reference in the union of dir1 and dir2, in order
 563 * by refname.  Recurse into subdirectories.  If a value entry appears
 564 * in both dir1 and dir2, then only process the version that is in
 565 * dir2.  The input dirs must already be sorted, but subdirs will be
 566 * sorted as needed.
 567 */
 568static int do_for_each_ref_in_dirs(struct ref_dir *dir1,
 569                                   struct ref_dir *dir2,
 570                                   const char *base, each_ref_fn fn, int trim,
 571                                   int flags, void *cb_data)
 572{
 573        int retval;
 574        int i1 = 0, i2 = 0;
 575
 576        assert(dir1->sorted == dir1->nr);
 577        assert(dir2->sorted == dir2->nr);
 578        while (1) {
 579                struct ref_entry *e1, *e2;
 580                int cmp;
 581                if (i1 == dir1->nr) {
 582                        return do_for_each_ref_in_dir(dir2, i2,
 583                                                      base, fn, trim, flags, cb_data);
 584                }
 585                if (i2 == dir2->nr) {
 586                        return do_for_each_ref_in_dir(dir1, i1,
 587                                                      base, fn, trim, flags, cb_data);
 588                }
 589                e1 = dir1->entries[i1];
 590                e2 = dir2->entries[i2];
 591                cmp = strcmp(e1->name, e2->name);
 592                if (cmp == 0) {
 593                        if ((e1->flag & REF_DIR) && (e2->flag & REF_DIR)) {
 594                                /* Both are directories; descend them in parallel. */
 595                                struct ref_dir *subdir1 = get_ref_dir(e1);
 596                                struct ref_dir *subdir2 = get_ref_dir(e2);
 597                                sort_ref_dir(subdir1);
 598                                sort_ref_dir(subdir2);
 599                                retval = do_for_each_ref_in_dirs(
 600                                                subdir1, subdir2,
 601                                                base, fn, trim, flags, cb_data);
 602                                i1++;
 603                                i2++;
 604                        } else if (!(e1->flag & REF_DIR) && !(e2->flag & REF_DIR)) {
 605                                /* Both are references; ignore the one from dir1. */
 606                                retval = do_one_ref(base, fn, trim, flags, cb_data, e2);
 607                                i1++;
 608                                i2++;
 609                        } else {
 610                                die("conflict between reference and directory: %s",
 611                                    e1->name);
 612                        }
 613                } else {
 614                        struct ref_entry *e;
 615                        if (cmp < 0) {
 616                                e = e1;
 617                                i1++;
 618                        } else {
 619                                e = e2;
 620                                i2++;
 621                        }
 622                        if (e->flag & REF_DIR) {
 623                                struct ref_dir *subdir = get_ref_dir(e);
 624                                sort_ref_dir(subdir);
 625                                retval = do_for_each_ref_in_dir(
 626                                                subdir, 0,
 627                                                base, fn, trim, flags, cb_data);
 628                        } else {
 629                                retval = do_one_ref(base, fn, trim, flags, cb_data, e);
 630                        }
 631                }
 632                if (retval)
 633                        return retval;
 634        }
 635        if (i1 < dir1->nr)
 636                return do_for_each_ref_in_dir(dir1, i1,
 637                                              base, fn, trim, flags, cb_data);
 638        if (i2 < dir2->nr)
 639                return do_for_each_ref_in_dir(dir2, i2,
 640                                              base, fn, trim, flags, cb_data);
 641        return 0;
 642}
 643
 644/*
 645 * Return true iff refname1 and refname2 conflict with each other.
 646 * Two reference names conflict if one of them exactly matches the
 647 * leading components of the other; e.g., "foo/bar" conflicts with
 648 * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
 649 * "foo/barbados".
 650 */
 651static int names_conflict(const char *refname1, const char *refname2)
 652{
 653        for (; *refname1 && *refname1 == *refname2; refname1++, refname2++)
 654                ;
 655        return (*refname1 == '\0' && *refname2 == '/')
 656                || (*refname1 == '/' && *refname2 == '\0');
 657}
 658
 659struct name_conflict_cb {
 660        const char *refname;
 661        const char *oldrefname;
 662        const char *conflicting_refname;
 663};
 664
 665static int name_conflict_fn(const char *existingrefname, const unsigned char *sha1,
 666                            int flags, void *cb_data)
 667{
 668        struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
 669        if (data->oldrefname && !strcmp(data->oldrefname, existingrefname))
 670                return 0;
 671        if (names_conflict(data->refname, existingrefname)) {
 672                data->conflicting_refname = existingrefname;
 673                return 1;
 674        }
 675        return 0;
 676}
 677
 678/*
 679 * Return true iff a reference named refname could be created without
 680 * conflicting with the name of an existing reference in array.  If
 681 * oldrefname is non-NULL, ignore potential conflicts with oldrefname
 682 * (e.g., because oldrefname is scheduled for deletion in the same
 683 * operation).
 684 */
 685static int is_refname_available(const char *refname, const char *oldrefname,
 686                                struct ref_dir *dir)
 687{
 688        struct name_conflict_cb data;
 689        data.refname = refname;
 690        data.oldrefname = oldrefname;
 691        data.conflicting_refname = NULL;
 692
 693        sort_ref_dir(dir);
 694        if (do_for_each_ref_in_dir(dir, 0, "", name_conflict_fn,
 695                                   0, DO_FOR_EACH_INCLUDE_BROKEN,
 696                                   &data)) {
 697                error("'%s' exists; cannot create '%s'",
 698                      data.conflicting_refname, refname);
 699                return 0;
 700        }
 701        return 1;
 702}
 703
 704/*
 705 * Future: need to be in "struct repository"
 706 * when doing a full libification.
 707 */
 708static struct ref_cache {
 709        struct ref_cache *next;
 710        struct ref_entry *loose;
 711        struct ref_entry *packed;
 712        /* The submodule name, or "" for the main repo. */
 713        char name[FLEX_ARRAY];
 714} *ref_cache;
 715
 716static void clear_packed_ref_cache(struct ref_cache *refs)
 717{
 718        if (refs->packed) {
 719                free_ref_entry(refs->packed);
 720                refs->packed = NULL;
 721        }
 722}
 723
 724static void clear_loose_ref_cache(struct ref_cache *refs)
 725{
 726        if (refs->loose) {
 727                free_ref_entry(refs->loose);
 728                refs->loose = NULL;
 729        }
 730}
 731
 732static struct ref_cache *create_ref_cache(const char *submodule)
 733{
 734        int len;
 735        struct ref_cache *refs;
 736        if (!submodule)
 737                submodule = "";
 738        len = strlen(submodule) + 1;
 739        refs = xcalloc(1, sizeof(struct ref_cache) + len);
 740        memcpy(refs->name, submodule, len);
 741        return refs;
 742}
 743
 744/*
 745 * Return a pointer to a ref_cache for the specified submodule. For
 746 * the main repository, use submodule==NULL. The returned structure
 747 * will be allocated and initialized but not necessarily populated; it
 748 * should not be freed.
 749 */
 750static struct ref_cache *get_ref_cache(const char *submodule)
 751{
 752        struct ref_cache *refs = ref_cache;
 753        if (!submodule)
 754                submodule = "";
 755        while (refs) {
 756                if (!strcmp(submodule, refs->name))
 757                        return refs;
 758                refs = refs->next;
 759        }
 760
 761        refs = create_ref_cache(submodule);
 762        refs->next = ref_cache;
 763        ref_cache = refs;
 764        return refs;
 765}
 766
 767void invalidate_ref_cache(const char *submodule)
 768{
 769        struct ref_cache *refs = get_ref_cache(submodule);
 770        clear_packed_ref_cache(refs);
 771        clear_loose_ref_cache(refs);
 772}
 773
 774/*
 775 * Parse one line from a packed-refs file.  Write the SHA1 to sha1.
 776 * Return a pointer to the refname within the line (null-terminated),
 777 * or NULL if there was a problem.
 778 */
 779static const char *parse_ref_line(char *line, unsigned char *sha1)
 780{
 781        /*
 782         * 42: the answer to everything.
 783         *
 784         * In this case, it happens to be the answer to
 785         *  40 (length of sha1 hex representation)
 786         *  +1 (space in between hex and name)
 787         *  +1 (newline at the end of the line)
 788         */
 789        int len = strlen(line) - 42;
 790
 791        if (len <= 0)
 792                return NULL;
 793        if (get_sha1_hex(line, sha1) < 0)
 794                return NULL;
 795        if (!isspace(line[40]))
 796                return NULL;
 797        line += 41;
 798        if (isspace(*line))
 799                return NULL;
 800        if (line[len] != '\n')
 801                return NULL;
 802        line[len] = 0;
 803
 804        return line;
 805}
 806
 807static void read_packed_refs(FILE *f, struct ref_dir *dir)
 808{
 809        struct ref_entry *last = NULL;
 810        char refline[PATH_MAX];
 811        int flag = REF_ISPACKED;
 812
 813        while (fgets(refline, sizeof(refline), f)) {
 814                unsigned char sha1[20];
 815                const char *refname;
 816                static const char header[] = "# pack-refs with:";
 817
 818                if (!strncmp(refline, header, sizeof(header)-1)) {
 819                        const char *traits = refline + sizeof(header) - 1;
 820                        if (strstr(traits, " peeled "))
 821                                flag |= REF_KNOWS_PEELED;
 822                        /* perhaps other traits later as well */
 823                        continue;
 824                }
 825
 826                refname = parse_ref_line(refline, sha1);
 827                if (refname) {
 828                        last = create_ref_entry(refname, sha1, flag, 1);
 829                        add_ref(dir, last);
 830                        continue;
 831                }
 832                if (last &&
 833                    refline[0] == '^' &&
 834                    strlen(refline) == 42 &&
 835                    refline[41] == '\n' &&
 836                    !get_sha1_hex(refline + 1, sha1))
 837                        hashcpy(last->u.value.peeled, sha1);
 838        }
 839}
 840
 841static struct ref_dir *get_packed_refs(struct ref_cache *refs)
 842{
 843        if (!refs->packed) {
 844                const char *packed_refs_file;
 845                FILE *f;
 846
 847                refs->packed = create_dir_entry(refs, "", 0, 0);
 848                if (*refs->name)
 849                        packed_refs_file = git_path_submodule(refs->name, "packed-refs");
 850                else
 851                        packed_refs_file = git_path("packed-refs");
 852                f = fopen(packed_refs_file, "r");
 853                if (f) {
 854                        read_packed_refs(f, get_ref_dir(refs->packed));
 855                        fclose(f);
 856                }
 857        }
 858        return get_ref_dir(refs->packed);
 859}
 860
 861void add_packed_ref(const char *refname, const unsigned char *sha1)
 862{
 863        add_ref(get_packed_refs(get_ref_cache(NULL)),
 864                        create_ref_entry(refname, sha1, REF_ISPACKED, 1));
 865}
 866
 867/*
 868 * Read the loose references from the namespace dirname into dir
 869 * (without recursing).  dirname must end with '/'.  dir must be the
 870 * directory entry corresponding to dirname.
 871 */
 872static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 873{
 874        struct ref_cache *refs = dir->ref_cache;
 875        DIR *d;
 876        const char *path;
 877        struct dirent *de;
 878        int dirnamelen = strlen(dirname);
 879        struct strbuf refname;
 880
 881        if (*refs->name)
 882                path = git_path_submodule(refs->name, "%s", dirname);
 883        else
 884                path = git_path("%s", dirname);
 885
 886        d = opendir(path);
 887        if (!d)
 888                return;
 889
 890        strbuf_init(&refname, dirnamelen + 257);
 891        strbuf_add(&refname, dirname, dirnamelen);
 892
 893        while ((de = readdir(d)) != NULL) {
 894                unsigned char sha1[20];
 895                struct stat st;
 896                int flag;
 897                const char *refdir;
 898
 899                if (de->d_name[0] == '.')
 900                        continue;
 901                if (has_extension(de->d_name, ".lock"))
 902                        continue;
 903                strbuf_addstr(&refname, de->d_name);
 904                refdir = *refs->name
 905                        ? git_path_submodule(refs->name, "%s", refname.buf)
 906                        : git_path("%s", refname.buf);
 907                if (stat(refdir, &st) < 0) {
 908                        ; /* silently ignore */
 909                } else if (S_ISDIR(st.st_mode)) {
 910                        strbuf_addch(&refname, '/');
 911                        add_entry_to_dir(dir,
 912                                         create_dir_entry(refs, refname.buf,
 913                                                          refname.len, 1));
 914                } else {
 915                        if (*refs->name) {
 916                                hashclr(sha1);
 917                                flag = 0;
 918                                if (resolve_gitlink_ref(refs->name, refname.buf, sha1) < 0) {
 919                                        hashclr(sha1);
 920                                        flag |= REF_ISBROKEN;
 921                                }
 922                        } else if (read_ref_full(refname.buf, sha1, 1, &flag)) {
 923                                hashclr(sha1);
 924                                flag |= REF_ISBROKEN;
 925                        }
 926                        add_entry_to_dir(dir,
 927                                         create_ref_entry(refname.buf, sha1, flag, 1));
 928                }
 929                strbuf_setlen(&refname, dirnamelen);
 930        }
 931        strbuf_release(&refname);
 932        closedir(d);
 933}
 934
 935static struct ref_dir *get_loose_refs(struct ref_cache *refs)
 936{
 937        if (!refs->loose) {
 938                /*
 939                 * Mark the top-level directory complete because we
 940                 * are about to read the only subdirectory that can
 941                 * hold references:
 942                 */
 943                refs->loose = create_dir_entry(refs, "", 0, 0);
 944                /*
 945                 * Create an incomplete entry for "refs/":
 946                 */
 947                add_entry_to_dir(get_ref_dir(refs->loose),
 948                                 create_dir_entry(refs, "refs/", 5, 1));
 949        }
 950        return get_ref_dir(refs->loose);
 951}
 952
 953/* We allow "recursive" symbolic refs. Only within reason, though */
 954#define MAXDEPTH 5
 955#define MAXREFLEN (1024)
 956
 957/*
 958 * Called by resolve_gitlink_ref_recursive() after it failed to read
 959 * from the loose refs in ref_cache refs. Find <refname> in the
 960 * packed-refs file for the submodule.
 961 */
 962static int resolve_gitlink_packed_ref(struct ref_cache *refs,
 963                                      const char *refname, unsigned char *sha1)
 964{
 965        struct ref_entry *ref;
 966        struct ref_dir *dir = get_packed_refs(refs);
 967
 968        ref = find_ref(dir, refname);
 969        if (ref == NULL)
 970                return -1;
 971
 972        memcpy(sha1, ref->u.value.sha1, 20);
 973        return 0;
 974}
 975
 976static int resolve_gitlink_ref_recursive(struct ref_cache *refs,
 977                                         const char *refname, unsigned char *sha1,
 978                                         int recursion)
 979{
 980        int fd, len;
 981        char buffer[128], *p;
 982        char *path;
 983
 984        if (recursion > MAXDEPTH || strlen(refname) > MAXREFLEN)
 985                return -1;
 986        path = *refs->name
 987                ? git_path_submodule(refs->name, "%s", refname)
 988                : git_path("%s", refname);
 989        fd = open(path, O_RDONLY);
 990        if (fd < 0)
 991                return resolve_gitlink_packed_ref(refs, refname, sha1);
 992
 993        len = read(fd, buffer, sizeof(buffer)-1);
 994        close(fd);
 995        if (len < 0)
 996                return -1;
 997        while (len && isspace(buffer[len-1]))
 998                len--;
 999        buffer[len] = 0;
1000
1001        /* Was it a detached head or an old-fashioned symlink? */
1002        if (!get_sha1_hex(buffer, sha1))
1003                return 0;
1004
1005        /* Symref? */
1006        if (strncmp(buffer, "ref:", 4))
1007                return -1;
1008        p = buffer + 4;
1009        while (isspace(*p))
1010                p++;
1011
1012        return resolve_gitlink_ref_recursive(refs, p, sha1, recursion+1);
1013}
1014
1015int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *sha1)
1016{
1017        int len = strlen(path), retval;
1018        char *submodule;
1019        struct ref_cache *refs;
1020
1021        while (len && path[len-1] == '/')
1022                len--;
1023        if (!len)
1024                return -1;
1025        submodule = xstrndup(path, len);
1026        refs = get_ref_cache(submodule);
1027        free(submodule);
1028
1029        retval = resolve_gitlink_ref_recursive(refs, refname, sha1, 0);
1030        return retval;
1031}
1032
1033/*
1034 * Try to read ref from the packed references.  On success, set sha1
1035 * and return 0; otherwise, return -1.
1036 */
1037static int get_packed_ref(const char *refname, unsigned char *sha1)
1038{
1039        struct ref_dir *packed = get_packed_refs(get_ref_cache(NULL));
1040        struct ref_entry *entry = find_ref(packed, refname);
1041        if (entry) {
1042                hashcpy(sha1, entry->u.value.sha1);
1043                return 0;
1044        }
1045        return -1;
1046}
1047
1048const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int reading, int *flag)
1049{
1050        int depth = MAXDEPTH;
1051        ssize_t len;
1052        char buffer[256];
1053        static char refname_buffer[256];
1054
1055        if (flag)
1056                *flag = 0;
1057
1058        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
1059                return NULL;
1060
1061        for (;;) {
1062                char path[PATH_MAX];
1063                struct stat st;
1064                char *buf;
1065                int fd;
1066
1067                if (--depth < 0)
1068                        return NULL;
1069
1070                git_snpath(path, sizeof(path), "%s", refname);
1071
1072                if (lstat(path, &st) < 0) {
1073                        if (errno != ENOENT)
1074                                return NULL;
1075                        /*
1076                         * The loose reference file does not exist;
1077                         * check for a packed reference.
1078                         */
1079                        if (!get_packed_ref(refname, sha1)) {
1080                                if (flag)
1081                                        *flag |= REF_ISPACKED;
1082                                return refname;
1083                        }
1084                        /* The reference is not a packed reference, either. */
1085                        if (reading) {
1086                                return NULL;
1087                        } else {
1088                                hashclr(sha1);
1089                                return refname;
1090                        }
1091                }
1092
1093                /* Follow "normalized" - ie "refs/.." symlinks by hand */
1094                if (S_ISLNK(st.st_mode)) {
1095                        len = readlink(path, buffer, sizeof(buffer)-1);
1096                        if (len < 0)
1097                                return NULL;
1098                        buffer[len] = 0;
1099                        if (!prefixcmp(buffer, "refs/") &&
1100                                        !check_refname_format(buffer, 0)) {
1101                                strcpy(refname_buffer, buffer);
1102                                refname = refname_buffer;
1103                                if (flag)
1104                                        *flag |= REF_ISSYMREF;
1105                                continue;
1106                        }
1107                }
1108
1109                /* Is it a directory? */
1110                if (S_ISDIR(st.st_mode)) {
1111                        errno = EISDIR;
1112                        return NULL;
1113                }
1114
1115                /*
1116                 * Anything else, just open it and try to use it as
1117                 * a ref
1118                 */
1119                fd = open(path, O_RDONLY);
1120                if (fd < 0)
1121                        return NULL;
1122                len = read_in_full(fd, buffer, sizeof(buffer)-1);
1123                close(fd);
1124                if (len < 0)
1125                        return NULL;
1126                while (len && isspace(buffer[len-1]))
1127                        len--;
1128                buffer[len] = '\0';
1129
1130                /*
1131                 * Is it a symbolic ref?
1132                 */
1133                if (prefixcmp(buffer, "ref:"))
1134                        break;
1135                if (flag)
1136                        *flag |= REF_ISSYMREF;
1137                buf = buffer + 4;
1138                while (isspace(*buf))
1139                        buf++;
1140                if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
1141                        if (flag)
1142                                *flag |= REF_ISBROKEN;
1143                        return NULL;
1144                }
1145                refname = strcpy(refname_buffer, buf);
1146        }
1147        /* Please note that FETCH_HEAD has a second line containing other data. */
1148        if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
1149                if (flag)
1150                        *flag |= REF_ISBROKEN;
1151                return NULL;
1152        }
1153        return refname;
1154}
1155
1156char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, int *flag)
1157{
1158        const char *ret = resolve_ref_unsafe(ref, sha1, reading, flag);
1159        return ret ? xstrdup(ret) : NULL;
1160}
1161
1162/* The argument to filter_refs */
1163struct ref_filter {
1164        const char *pattern;
1165        each_ref_fn *fn;
1166        void *cb_data;
1167};
1168
1169int read_ref_full(const char *refname, unsigned char *sha1, int reading, int *flags)
1170{
1171        if (resolve_ref_unsafe(refname, sha1, reading, flags))
1172                return 0;
1173        return -1;
1174}
1175
1176int read_ref(const char *refname, unsigned char *sha1)
1177{
1178        return read_ref_full(refname, sha1, 1, NULL);
1179}
1180
1181int ref_exists(const char *refname)
1182{
1183        unsigned char sha1[20];
1184        return !!resolve_ref_unsafe(refname, sha1, 1, NULL);
1185}
1186
1187static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
1188                       void *data)
1189{
1190        struct ref_filter *filter = (struct ref_filter *)data;
1191        if (fnmatch(filter->pattern, refname, 0))
1192                return 0;
1193        return filter->fn(refname, sha1, flags, filter->cb_data);
1194}
1195
1196int peel_ref(const char *refname, unsigned char *sha1)
1197{
1198        int flag;
1199        unsigned char base[20];
1200        struct object *o;
1201
1202        if (current_ref && (current_ref->name == refname
1203                || !strcmp(current_ref->name, refname))) {
1204                if (current_ref->flag & REF_KNOWS_PEELED) {
1205                        hashcpy(sha1, current_ref->u.value.peeled);
1206                        return 0;
1207                }
1208                hashcpy(base, current_ref->u.value.sha1);
1209                goto fallback;
1210        }
1211
1212        if (read_ref_full(refname, base, 1, &flag))
1213                return -1;
1214
1215        if ((flag & REF_ISPACKED)) {
1216                struct ref_dir *dir = get_packed_refs(get_ref_cache(NULL));
1217                struct ref_entry *r = find_ref(dir, refname);
1218
1219                if (r != NULL && r->flag & REF_KNOWS_PEELED) {
1220                        hashcpy(sha1, r->u.value.peeled);
1221                        return 0;
1222                }
1223        }
1224
1225fallback:
1226        o = parse_object(base);
1227        if (o && o->type == OBJ_TAG) {
1228                o = deref_tag(o, refname, 0);
1229                if (o) {
1230                        hashcpy(sha1, o->sha1);
1231                        return 0;
1232                }
1233        }
1234        return -1;
1235}
1236
1237struct warn_if_dangling_data {
1238        FILE *fp;
1239        const char *refname;
1240        const char *msg_fmt;
1241};
1242
1243static int warn_if_dangling_symref(const char *refname, const unsigned char *sha1,
1244                                   int flags, void *cb_data)
1245{
1246        struct warn_if_dangling_data *d = cb_data;
1247        const char *resolves_to;
1248        unsigned char junk[20];
1249
1250        if (!(flags & REF_ISSYMREF))
1251                return 0;
1252
1253        resolves_to = resolve_ref_unsafe(refname, junk, 0, NULL);
1254        if (!resolves_to || strcmp(resolves_to, d->refname))
1255                return 0;
1256
1257        fprintf(d->fp, d->msg_fmt, refname);
1258        fputc('\n', d->fp);
1259        return 0;
1260}
1261
1262void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
1263{
1264        struct warn_if_dangling_data data;
1265
1266        data.fp = fp;
1267        data.refname = refname;
1268        data.msg_fmt = msg_fmt;
1269        for_each_rawref(warn_if_dangling_symref, &data);
1270}
1271
1272static int do_for_each_ref(const char *submodule, const char *base, each_ref_fn fn,
1273                           int trim, int flags, void *cb_data)
1274{
1275        struct ref_cache *refs = get_ref_cache(submodule);
1276        struct ref_dir *packed_dir = get_packed_refs(refs);
1277        struct ref_dir *loose_dir = get_loose_refs(refs);
1278        int retval = 0;
1279
1280        if (base && *base) {
1281                packed_dir = find_containing_dir(packed_dir, base, 0);
1282                loose_dir = find_containing_dir(loose_dir, base, 0);
1283        }
1284
1285        if (packed_dir && loose_dir) {
1286                sort_ref_dir(packed_dir);
1287                sort_ref_dir(loose_dir);
1288                retval = do_for_each_ref_in_dirs(
1289                                packed_dir, loose_dir,
1290                                base, fn, trim, flags, cb_data);
1291        } else if (packed_dir) {
1292                sort_ref_dir(packed_dir);
1293                retval = do_for_each_ref_in_dir(
1294                                packed_dir, 0,
1295                                base, fn, trim, flags, cb_data);
1296        } else if (loose_dir) {
1297                sort_ref_dir(loose_dir);
1298                retval = do_for_each_ref_in_dir(
1299                                loose_dir, 0,
1300                                base, fn, trim, flags, cb_data);
1301        }
1302
1303        return retval;
1304}
1305
1306static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
1307{
1308        unsigned char sha1[20];
1309        int flag;
1310
1311        if (submodule) {
1312                if (resolve_gitlink_ref(submodule, "HEAD", sha1) == 0)
1313                        return fn("HEAD", sha1, 0, cb_data);
1314
1315                return 0;
1316        }
1317
1318        if (!read_ref_full("HEAD", sha1, 1, &flag))
1319                return fn("HEAD", sha1, flag, cb_data);
1320
1321        return 0;
1322}
1323
1324int head_ref(each_ref_fn fn, void *cb_data)
1325{
1326        return do_head_ref(NULL, fn, cb_data);
1327}
1328
1329int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1330{
1331        return do_head_ref(submodule, fn, cb_data);
1332}
1333
1334int for_each_ref(each_ref_fn fn, void *cb_data)
1335{
1336        return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
1337}
1338
1339int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1340{
1341        return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
1342}
1343
1344int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
1345{
1346        return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
1347}
1348
1349int for_each_ref_in_submodule(const char *submodule, const char *prefix,
1350                each_ref_fn fn, void *cb_data)
1351{
1352        return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
1353}
1354
1355int for_each_tag_ref(each_ref_fn fn, void *cb_data)
1356{
1357        return for_each_ref_in("refs/tags/", fn, cb_data);
1358}
1359
1360int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1361{
1362        return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
1363}
1364
1365int for_each_branch_ref(each_ref_fn fn, void *cb_data)
1366{
1367        return for_each_ref_in("refs/heads/", fn, cb_data);
1368}
1369
1370int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1371{
1372        return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
1373}
1374
1375int for_each_remote_ref(each_ref_fn fn, void *cb_data)
1376{
1377        return for_each_ref_in("refs/remotes/", fn, cb_data);
1378}
1379
1380int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
1381{
1382        return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
1383}
1384
1385int for_each_replace_ref(each_ref_fn fn, void *cb_data)
1386{
1387        return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
1388}
1389
1390int head_ref_namespaced(each_ref_fn fn, void *cb_data)
1391{
1392        struct strbuf buf = STRBUF_INIT;
1393        int ret = 0;
1394        unsigned char sha1[20];
1395        int flag;
1396
1397        strbuf_addf(&buf, "%sHEAD", get_git_namespace());
1398        if (!read_ref_full(buf.buf, sha1, 1, &flag))
1399                ret = fn(buf.buf, sha1, flag, cb_data);
1400        strbuf_release(&buf);
1401
1402        return ret;
1403}
1404
1405int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
1406{
1407        struct strbuf buf = STRBUF_INIT;
1408        int ret;
1409        strbuf_addf(&buf, "%srefs/", get_git_namespace());
1410        ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
1411        strbuf_release(&buf);
1412        return ret;
1413}
1414
1415int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
1416        const char *prefix, void *cb_data)
1417{
1418        struct strbuf real_pattern = STRBUF_INIT;
1419        struct ref_filter filter;
1420        int ret;
1421
1422        if (!prefix && prefixcmp(pattern, "refs/"))
1423                strbuf_addstr(&real_pattern, "refs/");
1424        else if (prefix)
1425                strbuf_addstr(&real_pattern, prefix);
1426        strbuf_addstr(&real_pattern, pattern);
1427
1428        if (!has_glob_specials(pattern)) {
1429                /* Append implied '/' '*' if not present. */
1430                if (real_pattern.buf[real_pattern.len - 1] != '/')
1431                        strbuf_addch(&real_pattern, '/');
1432                /* No need to check for '*', there is none. */
1433                strbuf_addch(&real_pattern, '*');
1434        }
1435
1436        filter.pattern = real_pattern.buf;
1437        filter.fn = fn;
1438        filter.cb_data = cb_data;
1439        ret = for_each_ref(filter_refs, &filter);
1440
1441        strbuf_release(&real_pattern);
1442        return ret;
1443}
1444
1445int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
1446{
1447        return for_each_glob_ref_in(fn, pattern, NULL, cb_data);
1448}
1449
1450int for_each_rawref(each_ref_fn fn, void *cb_data)
1451{
1452        return do_for_each_ref(NULL, "", fn, 0,
1453                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
1454}
1455
1456const char *prettify_refname(const char *name)
1457{
1458        return name + (
1459                !prefixcmp(name, "refs/heads/") ? 11 :
1460                !prefixcmp(name, "refs/tags/") ? 10 :
1461                !prefixcmp(name, "refs/remotes/") ? 13 :
1462                0);
1463}
1464
1465const char *ref_rev_parse_rules[] = {
1466        "%.*s",
1467        "refs/%.*s",
1468        "refs/tags/%.*s",
1469        "refs/heads/%.*s",
1470        "refs/remotes/%.*s",
1471        "refs/remotes/%.*s/HEAD",
1472        NULL
1473};
1474
1475int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
1476{
1477        const char **p;
1478        const int abbrev_name_len = strlen(abbrev_name);
1479
1480        for (p = rules; *p; p++) {
1481                if (!strcmp(full_name, mkpath(*p, abbrev_name_len, abbrev_name))) {
1482                        return 1;
1483                }
1484        }
1485
1486        return 0;
1487}
1488
1489static struct ref_lock *verify_lock(struct ref_lock *lock,
1490        const unsigned char *old_sha1, int mustexist)
1491{
1492        if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
1493                error("Can't verify ref %s", lock->ref_name);
1494                unlock_ref(lock);
1495                return NULL;
1496        }
1497        if (hashcmp(lock->old_sha1, old_sha1)) {
1498                error("Ref %s is at %s but expected %s", lock->ref_name,
1499                        sha1_to_hex(lock->old_sha1), sha1_to_hex(old_sha1));
1500                unlock_ref(lock);
1501                return NULL;
1502        }
1503        return lock;
1504}
1505
1506static int remove_empty_directories(const char *file)
1507{
1508        /* we want to create a file but there is a directory there;
1509         * if that is an empty directory (or a directory that contains
1510         * only empty directories), remove them.
1511         */
1512        struct strbuf path;
1513        int result;
1514
1515        strbuf_init(&path, 20);
1516        strbuf_addstr(&path, file);
1517
1518        result = remove_dir_recursively(&path, REMOVE_DIR_EMPTY_ONLY);
1519
1520        strbuf_release(&path);
1521
1522        return result;
1523}
1524
1525/*
1526 * *string and *len will only be substituted, and *string returned (for
1527 * later free()ing) if the string passed in is a magic short-hand form
1528 * to name a branch.
1529 */
1530static char *substitute_branch_name(const char **string, int *len)
1531{
1532        struct strbuf buf = STRBUF_INIT;
1533        int ret = interpret_branch_name(*string, &buf);
1534
1535        if (ret == *len) {
1536                size_t size;
1537                *string = strbuf_detach(&buf, &size);
1538                *len = size;
1539                return (char *)*string;
1540        }
1541
1542        return NULL;
1543}
1544
1545int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
1546{
1547        char *last_branch = substitute_branch_name(&str, &len);
1548        const char **p, *r;
1549        int refs_found = 0;
1550
1551        *ref = NULL;
1552        for (p = ref_rev_parse_rules; *p; p++) {
1553                char fullref[PATH_MAX];
1554                unsigned char sha1_from_ref[20];
1555                unsigned char *this_result;
1556                int flag;
1557
1558                this_result = refs_found ? sha1_from_ref : sha1;
1559                mksnpath(fullref, sizeof(fullref), *p, len, str);
1560                r = resolve_ref_unsafe(fullref, this_result, 1, &flag);
1561                if (r) {
1562                        if (!refs_found++)
1563                                *ref = xstrdup(r);
1564                        if (!warn_ambiguous_refs)
1565                                break;
1566                } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
1567                        warning("ignoring dangling symref %s.", fullref);
1568                } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
1569                        warning("ignoring broken ref %s.", fullref);
1570                }
1571        }
1572        free(last_branch);
1573        return refs_found;
1574}
1575
1576int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
1577{
1578        char *last_branch = substitute_branch_name(&str, &len);
1579        const char **p;
1580        int logs_found = 0;
1581
1582        *log = NULL;
1583        for (p = ref_rev_parse_rules; *p; p++) {
1584                struct stat st;
1585                unsigned char hash[20];
1586                char path[PATH_MAX];
1587                const char *ref, *it;
1588
1589                mksnpath(path, sizeof(path), *p, len, str);
1590                ref = resolve_ref_unsafe(path, hash, 1, NULL);
1591                if (!ref)
1592                        continue;
1593                if (!stat(git_path("logs/%s", path), &st) &&
1594                    S_ISREG(st.st_mode))
1595                        it = path;
1596                else if (strcmp(ref, path) &&
1597                         !stat(git_path("logs/%s", ref), &st) &&
1598                         S_ISREG(st.st_mode))
1599                        it = ref;
1600                else
1601                        continue;
1602                if (!logs_found++) {
1603                        *log = xstrdup(it);
1604                        hashcpy(sha1, hash);
1605                }
1606                if (!warn_ambiguous_refs)
1607                        break;
1608        }
1609        free(last_branch);
1610        return logs_found;
1611}
1612
1613static struct ref_lock *lock_ref_sha1_basic(const char *refname,
1614                                            const unsigned char *old_sha1,
1615                                            int flags, int *type_p)
1616{
1617        char *ref_file;
1618        const char *orig_refname = refname;
1619        struct ref_lock *lock;
1620        int last_errno = 0;
1621        int type, lflags;
1622        int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
1623        int missing = 0;
1624
1625        lock = xcalloc(1, sizeof(struct ref_lock));
1626        lock->lock_fd = -1;
1627
1628        refname = resolve_ref_unsafe(refname, lock->old_sha1, mustexist, &type);
1629        if (!refname && errno == EISDIR) {
1630                /* we are trying to lock foo but we used to
1631                 * have foo/bar which now does not exist;
1632                 * it is normal for the empty directory 'foo'
1633                 * to remain.
1634                 */
1635                ref_file = git_path("%s", orig_refname);
1636                if (remove_empty_directories(ref_file)) {
1637                        last_errno = errno;
1638                        error("there are still refs under '%s'", orig_refname);
1639                        goto error_return;
1640                }
1641                refname = resolve_ref_unsafe(orig_refname, lock->old_sha1, mustexist, &type);
1642        }
1643        if (type_p)
1644            *type_p = type;
1645        if (!refname) {
1646                last_errno = errno;
1647                error("unable to resolve reference %s: %s",
1648                        orig_refname, strerror(errno));
1649                goto error_return;
1650        }
1651        missing = is_null_sha1(lock->old_sha1);
1652        /* When the ref did not exist and we are creating it,
1653         * make sure there is no existing ref that is packed
1654         * whose name begins with our refname, nor a ref whose
1655         * name is a proper prefix of our refname.
1656         */
1657        if (missing &&
1658             !is_refname_available(refname, NULL, get_packed_refs(get_ref_cache(NULL)))) {
1659                last_errno = ENOTDIR;
1660                goto error_return;
1661        }
1662
1663        lock->lk = xcalloc(1, sizeof(struct lock_file));
1664
1665        lflags = LOCK_DIE_ON_ERROR;
1666        if (flags & REF_NODEREF) {
1667                refname = orig_refname;
1668                lflags |= LOCK_NODEREF;
1669        }
1670        lock->ref_name = xstrdup(refname);
1671        lock->orig_ref_name = xstrdup(orig_refname);
1672        ref_file = git_path("%s", refname);
1673        if (missing)
1674                lock->force_write = 1;
1675        if ((flags & REF_NODEREF) && (type & REF_ISSYMREF))
1676                lock->force_write = 1;
1677
1678        if (safe_create_leading_directories(ref_file)) {
1679                last_errno = errno;
1680                error("unable to create directory for %s", ref_file);
1681                goto error_return;
1682        }
1683
1684        lock->lock_fd = hold_lock_file_for_update(lock->lk, ref_file, lflags);
1685        return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
1686
1687 error_return:
1688        unlock_ref(lock);
1689        errno = last_errno;
1690        return NULL;
1691}
1692
1693struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
1694{
1695        char refpath[PATH_MAX];
1696        if (check_refname_format(refname, 0))
1697                return NULL;
1698        strcpy(refpath, mkpath("refs/%s", refname));
1699        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
1700}
1701
1702struct ref_lock *lock_any_ref_for_update(const char *refname,
1703                                         const unsigned char *old_sha1, int flags)
1704{
1705        if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
1706                return NULL;
1707        return lock_ref_sha1_basic(refname, old_sha1, flags, NULL);
1708}
1709
1710struct repack_without_ref_sb {
1711        const char *refname;
1712        int fd;
1713};
1714
1715static int repack_without_ref_fn(const char *refname, const unsigned char *sha1,
1716                                 int flags, void *cb_data)
1717{
1718        struct repack_without_ref_sb *data = cb_data;
1719        char line[PATH_MAX + 100];
1720        int len;
1721
1722        if (!strcmp(data->refname, refname))
1723                return 0;
1724        len = snprintf(line, sizeof(line), "%s %s\n",
1725                       sha1_to_hex(sha1), refname);
1726        /* this should not happen but just being defensive */
1727        if (len > sizeof(line))
1728                die("too long a refname '%s'", refname);
1729        write_or_die(data->fd, line, len);
1730        return 0;
1731}
1732
1733static struct lock_file packlock;
1734
1735static int repack_without_ref(const char *refname)
1736{
1737        struct repack_without_ref_sb data;
1738        struct ref_dir *packed = get_packed_refs(get_ref_cache(NULL));
1739        if (find_ref(packed, refname) == NULL)
1740                return 0;
1741        data.refname = refname;
1742        data.fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
1743        if (data.fd < 0) {
1744                unable_to_lock_error(git_path("packed-refs"), errno);
1745                return error("cannot delete '%s' from packed refs", refname);
1746        }
1747        do_for_each_ref_in_dir(packed, 0, "", repack_without_ref_fn, 0, 0, &data);
1748        return commit_lock_file(&packlock);
1749}
1750
1751int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
1752{
1753        struct ref_lock *lock;
1754        int err, i = 0, ret = 0, flag = 0;
1755
1756        lock = lock_ref_sha1_basic(refname, sha1, 0, &flag);
1757        if (!lock)
1758                return 1;
1759        if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
1760                /* loose */
1761                const char *path;
1762
1763                if (!(delopt & REF_NODEREF)) {
1764                        i = strlen(lock->lk->filename) - 5; /* .lock */
1765                        lock->lk->filename[i] = 0;
1766                        path = lock->lk->filename;
1767                } else {
1768                        path = git_path("%s", refname);
1769                }
1770                err = unlink_or_warn(path);
1771                if (err && errno != ENOENT)
1772                        ret = 1;
1773
1774                if (!(delopt & REF_NODEREF))
1775                        lock->lk->filename[i] = '.';
1776        }
1777        /* removing the loose one could have resurrected an earlier
1778         * packed one.  Also, if it was not loose we need to repack
1779         * without it.
1780         */
1781        ret |= repack_without_ref(refname);
1782
1783        unlink_or_warn(git_path("logs/%s", lock->ref_name));
1784        invalidate_ref_cache(NULL);
1785        unlock_ref(lock);
1786        return ret;
1787}
1788
1789/*
1790 * People using contrib's git-new-workdir have .git/logs/refs ->
1791 * /some/other/path/.git/logs/refs, and that may live on another device.
1792 *
1793 * IOW, to avoid cross device rename errors, the temporary renamed log must
1794 * live into logs/refs.
1795 */
1796#define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
1797
1798int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
1799{
1800        unsigned char sha1[20], orig_sha1[20];
1801        int flag = 0, logmoved = 0;
1802        struct ref_lock *lock;
1803        struct stat loginfo;
1804        int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
1805        const char *symref = NULL;
1806        struct ref_cache *refs = get_ref_cache(NULL);
1807
1808        if (log && S_ISLNK(loginfo.st_mode))
1809                return error("reflog for %s is a symlink", oldrefname);
1810
1811        symref = resolve_ref_unsafe(oldrefname, orig_sha1, 1, &flag);
1812        if (flag & REF_ISSYMREF)
1813                return error("refname %s is a symbolic ref, renaming it is not supported",
1814                        oldrefname);
1815        if (!symref)
1816                return error("refname %s not found", oldrefname);
1817
1818        if (!is_refname_available(newrefname, oldrefname, get_packed_refs(refs)))
1819                return 1;
1820
1821        if (!is_refname_available(newrefname, oldrefname, get_loose_refs(refs)))
1822                return 1;
1823
1824        if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
1825                return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
1826                        oldrefname, strerror(errno));
1827
1828        if (delete_ref(oldrefname, orig_sha1, REF_NODEREF)) {
1829                error("unable to delete old %s", oldrefname);
1830                goto rollback;
1831        }
1832
1833        if (!read_ref_full(newrefname, sha1, 1, &flag) &&
1834            delete_ref(newrefname, sha1, REF_NODEREF)) {
1835                if (errno==EISDIR) {
1836                        if (remove_empty_directories(git_path("%s", newrefname))) {
1837                                error("Directory not empty: %s", newrefname);
1838                                goto rollback;
1839                        }
1840                } else {
1841                        error("unable to delete existing %s", newrefname);
1842                        goto rollback;
1843                }
1844        }
1845
1846        if (log && safe_create_leading_directories(git_path("logs/%s", newrefname))) {
1847                error("unable to create directory for %s", newrefname);
1848                goto rollback;
1849        }
1850
1851 retry:
1852        if (log && rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", newrefname))) {
1853                if (errno==EISDIR || errno==ENOTDIR) {
1854                        /*
1855                         * rename(a, b) when b is an existing
1856                         * directory ought to result in ISDIR, but
1857                         * Solaris 5.8 gives ENOTDIR.  Sheesh.
1858                         */
1859                        if (remove_empty_directories(git_path("logs/%s", newrefname))) {
1860                                error("Directory not empty: logs/%s", newrefname);
1861                                goto rollback;
1862                        }
1863                        goto retry;
1864                } else {
1865                        error("unable to move logfile "TMP_RENAMED_LOG" to logs/%s: %s",
1866                                newrefname, strerror(errno));
1867                        goto rollback;
1868                }
1869        }
1870        logmoved = log;
1871
1872        lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
1873        if (!lock) {
1874                error("unable to lock %s for update", newrefname);
1875                goto rollback;
1876        }
1877        lock->force_write = 1;
1878        hashcpy(lock->old_sha1, orig_sha1);
1879        if (write_ref_sha1(lock, orig_sha1, logmsg)) {
1880                error("unable to write current sha1 into %s", newrefname);
1881                goto rollback;
1882        }
1883
1884        return 0;
1885
1886 rollback:
1887        lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
1888        if (!lock) {
1889                error("unable to lock %s for rollback", oldrefname);
1890                goto rollbacklog;
1891        }
1892
1893        lock->force_write = 1;
1894        flag = log_all_ref_updates;
1895        log_all_ref_updates = 0;
1896        if (write_ref_sha1(lock, orig_sha1, NULL))
1897                error("unable to write current sha1 into %s", oldrefname);
1898        log_all_ref_updates = flag;
1899
1900 rollbacklog:
1901        if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
1902                error("unable to restore logfile %s from %s: %s",
1903                        oldrefname, newrefname, strerror(errno));
1904        if (!logmoved && log &&
1905            rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
1906                error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
1907                        oldrefname, strerror(errno));
1908
1909        return 1;
1910}
1911
1912int close_ref(struct ref_lock *lock)
1913{
1914        if (close_lock_file(lock->lk))
1915                return -1;
1916        lock->lock_fd = -1;
1917        return 0;
1918}
1919
1920int commit_ref(struct ref_lock *lock)
1921{
1922        if (commit_lock_file(lock->lk))
1923                return -1;
1924        lock->lock_fd = -1;
1925        return 0;
1926}
1927
1928void unlock_ref(struct ref_lock *lock)
1929{
1930        /* Do not free lock->lk -- atexit() still looks at them */
1931        if (lock->lk)
1932                rollback_lock_file(lock->lk);
1933        free(lock->ref_name);
1934        free(lock->orig_ref_name);
1935        free(lock);
1936}
1937
1938/*
1939 * copy the reflog message msg to buf, which has been allocated sufficiently
1940 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
1941 * because reflog file is one line per entry.
1942 */
1943static int copy_msg(char *buf, const char *msg)
1944{
1945        char *cp = buf;
1946        char c;
1947        int wasspace = 1;
1948
1949        *cp++ = '\t';
1950        while ((c = *msg++)) {
1951                if (wasspace && isspace(c))
1952                        continue;
1953                wasspace = isspace(c);
1954                if (wasspace)
1955                        c = ' ';
1956                *cp++ = c;
1957        }
1958        while (buf < cp && isspace(cp[-1]))
1959                cp--;
1960        *cp++ = '\n';
1961        return cp - buf;
1962}
1963
1964int log_ref_setup(const char *refname, char *logfile, int bufsize)
1965{
1966        int logfd, oflags = O_APPEND | O_WRONLY;
1967
1968        git_snpath(logfile, bufsize, "logs/%s", refname);
1969        if (log_all_ref_updates &&
1970            (!prefixcmp(refname, "refs/heads/") ||
1971             !prefixcmp(refname, "refs/remotes/") ||
1972             !prefixcmp(refname, "refs/notes/") ||
1973             !strcmp(refname, "HEAD"))) {
1974                if (safe_create_leading_directories(logfile) < 0)
1975                        return error("unable to create directory for %s",
1976                                     logfile);
1977                oflags |= O_CREAT;
1978        }
1979
1980        logfd = open(logfile, oflags, 0666);
1981        if (logfd < 0) {
1982                if (!(oflags & O_CREAT) && errno == ENOENT)
1983                        return 0;
1984
1985                if ((oflags & O_CREAT) && errno == EISDIR) {
1986                        if (remove_empty_directories(logfile)) {
1987                                return error("There are still logs under '%s'",
1988                                             logfile);
1989                        }
1990                        logfd = open(logfile, oflags, 0666);
1991                }
1992
1993                if (logfd < 0)
1994                        return error("Unable to append to %s: %s",
1995                                     logfile, strerror(errno));
1996        }
1997
1998        adjust_shared_perm(logfile);
1999        close(logfd);
2000        return 0;
2001}
2002
2003static int log_ref_write(const char *refname, const unsigned char *old_sha1,
2004                         const unsigned char *new_sha1, const char *msg)
2005{
2006        int logfd, result, written, oflags = O_APPEND | O_WRONLY;
2007        unsigned maxlen, len;
2008        int msglen;
2009        char log_file[PATH_MAX];
2010        char *logrec;
2011        const char *committer;
2012
2013        if (log_all_ref_updates < 0)
2014                log_all_ref_updates = !is_bare_repository();
2015
2016        result = log_ref_setup(refname, log_file, sizeof(log_file));
2017        if (result)
2018                return result;
2019
2020        logfd = open(log_file, oflags);
2021        if (logfd < 0)
2022                return 0;
2023        msglen = msg ? strlen(msg) : 0;
2024        committer = git_committer_info(0);
2025        maxlen = strlen(committer) + msglen + 100;
2026        logrec = xmalloc(maxlen);
2027        len = sprintf(logrec, "%s %s %s\n",
2028                      sha1_to_hex(old_sha1),
2029                      sha1_to_hex(new_sha1),
2030                      committer);
2031        if (msglen)
2032                len += copy_msg(logrec + len - 1, msg) - 1;
2033        written = len <= maxlen ? write_in_full(logfd, logrec, len) : -1;
2034        free(logrec);
2035        if (close(logfd) != 0 || written != len)
2036                return error("Unable to append to %s", log_file);
2037        return 0;
2038}
2039
2040static int is_branch(const char *refname)
2041{
2042        return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
2043}
2044
2045int write_ref_sha1(struct ref_lock *lock,
2046        const unsigned char *sha1, const char *logmsg)
2047{
2048        static char term = '\n';
2049        struct object *o;
2050
2051        if (!lock)
2052                return -1;
2053        if (!lock->force_write && !hashcmp(lock->old_sha1, sha1)) {
2054                unlock_ref(lock);
2055                return 0;
2056        }
2057        o = parse_object(sha1);
2058        if (!o) {
2059                error("Trying to write ref %s with nonexistent object %s",
2060                        lock->ref_name, sha1_to_hex(sha1));
2061                unlock_ref(lock);
2062                return -1;
2063        }
2064        if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
2065                error("Trying to write non-commit object %s to branch %s",
2066                        sha1_to_hex(sha1), lock->ref_name);
2067                unlock_ref(lock);
2068                return -1;
2069        }
2070        if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
2071            write_in_full(lock->lock_fd, &term, 1) != 1
2072                || close_ref(lock) < 0) {
2073                error("Couldn't write %s", lock->lk->filename);
2074                unlock_ref(lock);
2075                return -1;
2076        }
2077        clear_loose_ref_cache(get_ref_cache(NULL));
2078        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
2079            (strcmp(lock->ref_name, lock->orig_ref_name) &&
2080             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
2081                unlock_ref(lock);
2082                return -1;
2083        }
2084        if (strcmp(lock->orig_ref_name, "HEAD") != 0) {
2085                /*
2086                 * Special hack: If a branch is updated directly and HEAD
2087                 * points to it (may happen on the remote side of a push
2088                 * for example) then logically the HEAD reflog should be
2089                 * updated too.
2090                 * A generic solution implies reverse symref information,
2091                 * but finding all symrefs pointing to the given branch
2092                 * would be rather costly for this rare event (the direct
2093                 * update of a branch) to be worth it.  So let's cheat and
2094                 * check with HEAD only which should cover 99% of all usage
2095                 * scenarios (even 100% of the default ones).
2096                 */
2097                unsigned char head_sha1[20];
2098                int head_flag;
2099                const char *head_ref;
2100                head_ref = resolve_ref_unsafe("HEAD", head_sha1, 1, &head_flag);
2101                if (head_ref && (head_flag & REF_ISSYMREF) &&
2102                    !strcmp(head_ref, lock->ref_name))
2103                        log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
2104        }
2105        if (commit_ref(lock)) {
2106                error("Couldn't set %s", lock->ref_name);
2107                unlock_ref(lock);
2108                return -1;
2109        }
2110        unlock_ref(lock);
2111        return 0;
2112}
2113
2114int create_symref(const char *ref_target, const char *refs_heads_master,
2115                  const char *logmsg)
2116{
2117        const char *lockpath;
2118        char ref[1000];
2119        int fd, len, written;
2120        char *git_HEAD = git_pathdup("%s", ref_target);
2121        unsigned char old_sha1[20], new_sha1[20];
2122
2123        if (logmsg && read_ref(ref_target, old_sha1))
2124                hashclr(old_sha1);
2125
2126        if (safe_create_leading_directories(git_HEAD) < 0)
2127                return error("unable to create directory for %s", git_HEAD);
2128
2129#ifndef NO_SYMLINK_HEAD
2130        if (prefer_symlink_refs) {
2131                unlink(git_HEAD);
2132                if (!symlink(refs_heads_master, git_HEAD))
2133                        goto done;
2134                fprintf(stderr, "no symlink - falling back to symbolic ref\n");
2135        }
2136#endif
2137
2138        len = snprintf(ref, sizeof(ref), "ref: %s\n", refs_heads_master);
2139        if (sizeof(ref) <= len) {
2140                error("refname too long: %s", refs_heads_master);
2141                goto error_free_return;
2142        }
2143        lockpath = mkpath("%s.lock", git_HEAD);
2144        fd = open(lockpath, O_CREAT | O_EXCL | O_WRONLY, 0666);
2145        if (fd < 0) {
2146                error("Unable to open %s for writing", lockpath);
2147                goto error_free_return;
2148        }
2149        written = write_in_full(fd, ref, len);
2150        if (close(fd) != 0 || written != len) {
2151                error("Unable to write to %s", lockpath);
2152                goto error_unlink_return;
2153        }
2154        if (rename(lockpath, git_HEAD) < 0) {
2155                error("Unable to create %s", git_HEAD);
2156                goto error_unlink_return;
2157        }
2158        if (adjust_shared_perm(git_HEAD)) {
2159                error("Unable to fix permissions on %s", lockpath);
2160        error_unlink_return:
2161                unlink_or_warn(lockpath);
2162        error_free_return:
2163                free(git_HEAD);
2164                return -1;
2165        }
2166
2167#ifndef NO_SYMLINK_HEAD
2168        done:
2169#endif
2170        if (logmsg && !read_ref(refs_heads_master, new_sha1))
2171                log_ref_write(ref_target, old_sha1, new_sha1, logmsg);
2172
2173        free(git_HEAD);
2174        return 0;
2175}
2176
2177static char *ref_msg(const char *line, const char *endp)
2178{
2179        const char *ep;
2180        line += 82;
2181        ep = memchr(line, '\n', endp - line);
2182        if (!ep)
2183                ep = endp;
2184        return xmemdupz(line, ep - line);
2185}
2186
2187int read_ref_at(const char *refname, unsigned long at_time, int cnt,
2188                unsigned char *sha1, char **msg,
2189                unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt)
2190{
2191        const char *logfile, *logdata, *logend, *rec, *lastgt, *lastrec;
2192        char *tz_c;
2193        int logfd, tz, reccnt = 0;
2194        struct stat st;
2195        unsigned long date;
2196        unsigned char logged_sha1[20];
2197        void *log_mapped;
2198        size_t mapsz;
2199
2200        logfile = git_path("logs/%s", refname);
2201        logfd = open(logfile, O_RDONLY, 0);
2202        if (logfd < 0)
2203                die_errno("Unable to read log '%s'", logfile);
2204        fstat(logfd, &st);
2205        if (!st.st_size)
2206                die("Log %s is empty.", logfile);
2207        mapsz = xsize_t(st.st_size);
2208        log_mapped = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, logfd, 0);
2209        logdata = log_mapped;
2210        close(logfd);
2211
2212        lastrec = NULL;
2213        rec = logend = logdata + st.st_size;
2214        while (logdata < rec) {
2215                reccnt++;
2216                if (logdata < rec && *(rec-1) == '\n')
2217                        rec--;
2218                lastgt = NULL;
2219                while (logdata < rec && *(rec-1) != '\n') {
2220                        rec--;
2221                        if (*rec == '>')
2222                                lastgt = rec;
2223                }
2224                if (!lastgt)
2225                        die("Log %s is corrupt.", logfile);
2226                date = strtoul(lastgt + 1, &tz_c, 10);
2227                if (date <= at_time || cnt == 0) {
2228                        tz = strtoul(tz_c, NULL, 10);
2229                        if (msg)
2230                                *msg = ref_msg(rec, logend);
2231                        if (cutoff_time)
2232                                *cutoff_time = date;
2233                        if (cutoff_tz)
2234                                *cutoff_tz = tz;
2235                        if (cutoff_cnt)
2236                                *cutoff_cnt = reccnt - 1;
2237                        if (lastrec) {
2238                                if (get_sha1_hex(lastrec, logged_sha1))
2239                                        die("Log %s is corrupt.", logfile);
2240                                if (get_sha1_hex(rec + 41, sha1))
2241                                        die("Log %s is corrupt.", logfile);
2242                                if (hashcmp(logged_sha1, sha1)) {
2243                                        warning("Log %s has gap after %s.",
2244                                                logfile, show_date(date, tz, DATE_RFC2822));
2245                                }
2246                        }
2247                        else if (date == at_time) {
2248                                if (get_sha1_hex(rec + 41, sha1))
2249                                        die("Log %s is corrupt.", logfile);
2250                        }
2251                        else {
2252                                if (get_sha1_hex(rec + 41, logged_sha1))
2253                                        die("Log %s is corrupt.", logfile);
2254                                if (hashcmp(logged_sha1, sha1)) {
2255                                        warning("Log %s unexpectedly ended on %s.",
2256                                                logfile, show_date(date, tz, DATE_RFC2822));
2257                                }
2258                        }
2259                        munmap(log_mapped, mapsz);
2260                        return 0;
2261                }
2262                lastrec = rec;
2263                if (cnt > 0)
2264                        cnt--;
2265        }
2266
2267        rec = logdata;
2268        while (rec < logend && *rec != '>' && *rec != '\n')
2269                rec++;
2270        if (rec == logend || *rec == '\n')
2271                die("Log %s is corrupt.", logfile);
2272        date = strtoul(rec + 1, &tz_c, 10);
2273        tz = strtoul(tz_c, NULL, 10);
2274        if (get_sha1_hex(logdata, sha1))
2275                die("Log %s is corrupt.", logfile);
2276        if (is_null_sha1(sha1)) {
2277                if (get_sha1_hex(logdata + 41, sha1))
2278                        die("Log %s is corrupt.", logfile);
2279        }
2280        if (msg)
2281                *msg = ref_msg(logdata, logend);
2282        munmap(log_mapped, mapsz);
2283
2284        if (cutoff_time)
2285                *cutoff_time = date;
2286        if (cutoff_tz)
2287                *cutoff_tz = tz;
2288        if (cutoff_cnt)
2289                *cutoff_cnt = reccnt;
2290        return 1;
2291}
2292
2293int for_each_recent_reflog_ent(const char *refname, each_reflog_ent_fn fn, long ofs, void *cb_data)
2294{
2295        const char *logfile;
2296        FILE *logfp;
2297        struct strbuf sb = STRBUF_INIT;
2298        int ret = 0;
2299
2300        logfile = git_path("logs/%s", refname);
2301        logfp = fopen(logfile, "r");
2302        if (!logfp)
2303                return -1;
2304
2305        if (ofs) {
2306                struct stat statbuf;
2307                if (fstat(fileno(logfp), &statbuf) ||
2308                    statbuf.st_size < ofs ||
2309                    fseek(logfp, -ofs, SEEK_END) ||
2310                    strbuf_getwholeline(&sb, logfp, '\n')) {
2311                        fclose(logfp);
2312                        strbuf_release(&sb);
2313                        return -1;
2314                }
2315        }
2316
2317        while (!strbuf_getwholeline(&sb, logfp, '\n')) {
2318                unsigned char osha1[20], nsha1[20];
2319                char *email_end, *message;
2320                unsigned long timestamp;
2321                int tz;
2322
2323                /* old SP new SP name <email> SP time TAB msg LF */
2324                if (sb.len < 83 || sb.buf[sb.len - 1] != '\n' ||
2325                    get_sha1_hex(sb.buf, osha1) || sb.buf[40] != ' ' ||
2326                    get_sha1_hex(sb.buf + 41, nsha1) || sb.buf[81] != ' ' ||
2327                    !(email_end = strchr(sb.buf + 82, '>')) ||
2328                    email_end[1] != ' ' ||
2329                    !(timestamp = strtoul(email_end + 2, &message, 10)) ||
2330                    !message || message[0] != ' ' ||
2331                    (message[1] != '+' && message[1] != '-') ||
2332                    !isdigit(message[2]) || !isdigit(message[3]) ||
2333                    !isdigit(message[4]) || !isdigit(message[5]))
2334                        continue; /* corrupt? */
2335                email_end[1] = '\0';
2336                tz = strtol(message + 1, NULL, 10);
2337                if (message[6] != '\t')
2338                        message += 6;
2339                else
2340                        message += 7;
2341                ret = fn(osha1, nsha1, sb.buf + 82, timestamp, tz, message,
2342                         cb_data);
2343                if (ret)
2344                        break;
2345        }
2346        fclose(logfp);
2347        strbuf_release(&sb);
2348        return ret;
2349}
2350
2351int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data)
2352{
2353        return for_each_recent_reflog_ent(refname, fn, 0, cb_data);
2354}
2355
2356/*
2357 * Call fn for each reflog in the namespace indicated by name.  name
2358 * must be empty or end with '/'.  Name will be used as a scratch
2359 * space, but its contents will be restored before return.
2360 */
2361static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data)
2362{
2363        DIR *d = opendir(git_path("logs/%s", name->buf));
2364        int retval = 0;
2365        struct dirent *de;
2366        int oldlen = name->len;
2367
2368        if (!d)
2369                return name->len ? errno : 0;
2370
2371        while ((de = readdir(d)) != NULL) {
2372                struct stat st;
2373
2374                if (de->d_name[0] == '.')
2375                        continue;
2376                if (has_extension(de->d_name, ".lock"))
2377                        continue;
2378                strbuf_addstr(name, de->d_name);
2379                if (stat(git_path("logs/%s", name->buf), &st) < 0) {
2380                        ; /* silently ignore */
2381                } else {
2382                        if (S_ISDIR(st.st_mode)) {
2383                                strbuf_addch(name, '/');
2384                                retval = do_for_each_reflog(name, fn, cb_data);
2385                        } else {
2386                                unsigned char sha1[20];
2387                                if (read_ref_full(name->buf, sha1, 0, NULL))
2388                                        retval = error("bad ref for %s", name->buf);
2389                                else
2390                                        retval = fn(name->buf, sha1, 0, cb_data);
2391                        }
2392                        if (retval)
2393                                break;
2394                }
2395                strbuf_setlen(name, oldlen);
2396        }
2397        closedir(d);
2398        return retval;
2399}
2400
2401int for_each_reflog(each_ref_fn fn, void *cb_data)
2402{
2403        int retval;
2404        struct strbuf name;
2405        strbuf_init(&name, PATH_MAX);
2406        retval = do_for_each_reflog(&name, fn, cb_data);
2407        strbuf_release(&name);
2408        return retval;
2409}
2410
2411int update_ref(const char *action, const char *refname,
2412                const unsigned char *sha1, const unsigned char *oldval,
2413                int flags, enum action_on_err onerr)
2414{
2415        static struct ref_lock *lock;
2416        lock = lock_any_ref_for_update(refname, oldval, flags);
2417        if (!lock) {
2418                const char *str = "Cannot lock the ref '%s'.";
2419                switch (onerr) {
2420                case MSG_ON_ERR: error(str, refname); break;
2421                case DIE_ON_ERR: die(str, refname); break;
2422                case QUIET_ON_ERR: break;
2423                }
2424                return 1;
2425        }
2426        if (write_ref_sha1(lock, sha1, action) < 0) {
2427                const char *str = "Cannot update the ref '%s'.";
2428                switch (onerr) {
2429                case MSG_ON_ERR: error(str, refname); break;
2430                case DIE_ON_ERR: die(str, refname); break;
2431                case QUIET_ON_ERR: break;
2432                }
2433                return 1;
2434        }
2435        return 0;
2436}
2437
2438struct ref *find_ref_by_name(const struct ref *list, const char *name)
2439{
2440        for ( ; list; list = list->next)
2441                if (!strcmp(list->name, name))
2442                        return (struct ref *)list;
2443        return NULL;
2444}
2445
2446/*
2447 * generate a format suitable for scanf from a ref_rev_parse_rules
2448 * rule, that is replace the "%.*s" spec with a "%s" spec
2449 */
2450static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
2451{
2452        char *spec;
2453
2454        spec = strstr(rule, "%.*s");
2455        if (!spec || strstr(spec + 4, "%.*s"))
2456                die("invalid rule in ref_rev_parse_rules: %s", rule);
2457
2458        /* copy all until spec */
2459        strncpy(scanf_fmt, rule, spec - rule);
2460        scanf_fmt[spec - rule] = '\0';
2461        /* copy new spec */
2462        strcat(scanf_fmt, "%s");
2463        /* copy remaining rule */
2464        strcat(scanf_fmt, spec + 4);
2465
2466        return;
2467}
2468
2469char *shorten_unambiguous_ref(const char *refname, int strict)
2470{
2471        int i;
2472        static char **scanf_fmts;
2473        static int nr_rules;
2474        char *short_name;
2475
2476        /* pre generate scanf formats from ref_rev_parse_rules[] */
2477        if (!nr_rules) {
2478                size_t total_len = 0;
2479
2480                /* the rule list is NULL terminated, count them first */
2481                for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
2482                        /* no +1 because strlen("%s") < strlen("%.*s") */
2483                        total_len += strlen(ref_rev_parse_rules[nr_rules]);
2484
2485                scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
2486
2487                total_len = 0;
2488                for (i = 0; i < nr_rules; i++) {
2489                        scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
2490                                        + total_len;
2491                        gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
2492                        total_len += strlen(ref_rev_parse_rules[i]);
2493                }
2494        }
2495
2496        /* bail out if there are no rules */
2497        if (!nr_rules)
2498                return xstrdup(refname);
2499
2500        /* buffer for scanf result, at most refname must fit */
2501        short_name = xstrdup(refname);
2502
2503        /* skip first rule, it will always match */
2504        for (i = nr_rules - 1; i > 0 ; --i) {
2505                int j;
2506                int rules_to_fail = i;
2507                int short_name_len;
2508
2509                if (1 != sscanf(refname, scanf_fmts[i], short_name))
2510                        continue;
2511
2512                short_name_len = strlen(short_name);
2513
2514                /*
2515                 * in strict mode, all (except the matched one) rules
2516                 * must fail to resolve to a valid non-ambiguous ref
2517                 */
2518                if (strict)
2519                        rules_to_fail = nr_rules;
2520
2521                /*
2522                 * check if the short name resolves to a valid ref,
2523                 * but use only rules prior to the matched one
2524                 */
2525                for (j = 0; j < rules_to_fail; j++) {
2526                        const char *rule = ref_rev_parse_rules[j];
2527                        char refname[PATH_MAX];
2528
2529                        /* skip matched rule */
2530                        if (i == j)
2531                                continue;
2532
2533                        /*
2534                         * the short name is ambiguous, if it resolves
2535                         * (with this previous rule) to a valid ref
2536                         * read_ref() returns 0 on success
2537                         */
2538                        mksnpath(refname, sizeof(refname),
2539                                 rule, short_name_len, short_name);
2540                        if (ref_exists(refname))
2541                                break;
2542                }
2543
2544                /*
2545                 * short name is non-ambiguous if all previous rules
2546                 * haven't resolved to a valid ref
2547                 */
2548                if (j == rules_to_fail)
2549                        return short_name;
2550        }
2551
2552        free(short_name);
2553        return xstrdup(refname);
2554}