refs / refs-internal.hon commit Merge branch 'jn/vcs-svn-cleanup' into maint (8134746)
   1#ifndef REFS_REFS_INTERNAL_H
   2#define REFS_REFS_INTERNAL_H
   3
   4/*
   5 * Data structures and functions for the internal use of the refs
   6 * module. Code outside of the refs module should use only the public
   7 * functions defined in "refs.h", and should *not* include this file.
   8 */
   9
  10/*
  11 * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
  12 * refs (i.e., because the reference is about to be deleted anyway).
  13 */
  14#define REF_DELETING    0x02
  15
  16/*
  17 * Used as a flag in ref_update::flags when a loose ref is being
  18 * pruned. This flag must only be used when REF_NODEREF is set.
  19 */
  20#define REF_ISPRUNING   0x04
  21
  22/*
  23 * Used as a flag in ref_update::flags when the reference should be
  24 * updated to new_sha1.
  25 */
  26#define REF_HAVE_NEW    0x08
  27
  28/*
  29 * Used as a flag in ref_update::flags when old_sha1 should be
  30 * checked.
  31 */
  32#define REF_HAVE_OLD    0x10
  33
  34/*
  35 * Used as a flag in ref_update::flags when the lockfile needs to be
  36 * committed.
  37 */
  38#define REF_NEEDS_COMMIT 0x20
  39
  40/*
  41 * 0x40 is REF_FORCE_CREATE_REFLOG, so skip it if you're adding a
  42 * value to ref_update::flags
  43 */
  44
  45/*
  46 * Used as a flag in ref_update::flags when we want to log a ref
  47 * update but not actually perform it.  This is used when a symbolic
  48 * ref update is split up.
  49 */
  50#define REF_LOG_ONLY 0x80
  51
  52/*
  53 * Internal flag, meaning that the containing ref_update was via an
  54 * update to HEAD.
  55 */
  56#define REF_UPDATE_VIA_HEAD 0x100
  57
  58/*
  59 * Used as a flag in ref_update::flags when the loose reference has
  60 * been deleted.
  61 */
  62#define REF_DELETED_LOOSE 0x200
  63
  64/*
  65 * Return true iff refname is minimally safe. "Safe" here means that
  66 * deleting a loose reference by this name will not do any damage, for
  67 * example by causing a file that is not a reference to be deleted.
  68 * This function does not check that the reference name is legal; for
  69 * that, use check_refname_format().
  70 *
  71 * A refname that starts with "refs/" is considered safe iff it
  72 * doesn't contain any "." or ".." components or consecutive '/'
  73 * characters, end with '/', or (on Windows) contain any '\'
  74 * characters. Names that do not start with "refs/" are considered
  75 * safe iff they consist entirely of upper case characters and '_'
  76 * (like "HEAD" and "MERGE_HEAD" but not "config" or "FOO/BAR").
  77 */
  78int refname_is_safe(const char *refname);
  79
  80enum peel_status {
  81        /* object was peeled successfully: */
  82        PEEL_PEELED = 0,
  83
  84        /*
  85         * object cannot be peeled because the named object (or an
  86         * object referred to by a tag in the peel chain), does not
  87         * exist.
  88         */
  89        PEEL_INVALID = -1,
  90
  91        /* object cannot be peeled because it is not a tag: */
  92        PEEL_NON_TAG = -2,
  93
  94        /* ref_entry contains no peeled value because it is a symref: */
  95        PEEL_IS_SYMREF = -3,
  96
  97        /*
  98         * ref_entry cannot be peeled because it is broken (i.e., the
  99         * symbolic reference cannot even be resolved to an object
 100         * name):
 101         */
 102        PEEL_BROKEN = -4
 103};
 104
 105/*
 106 * Peel the named object; i.e., if the object is a tag, resolve the
 107 * tag recursively until a non-tag is found.  If successful, store the
 108 * result to sha1 and return PEEL_PEELED.  If the object is not a tag
 109 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
 110 * and leave sha1 unchanged.
 111 */
 112enum peel_status peel_object(const unsigned char *name, unsigned char *sha1);
 113
 114/*
 115 * Copy the reflog message msg to buf, which has been allocated sufficiently
 116 * large, while cleaning up the whitespaces.  Especially, convert LF to space,
 117 * because reflog file is one line per entry.
 118 */
 119int copy_reflog_msg(char *buf, const char *msg);
 120
 121/**
 122 * Information needed for a single ref update. Set new_sha1 to the new
 123 * value or to null_sha1 to delete the ref. To check the old value
 124 * while the ref is locked, set (flags & REF_HAVE_OLD) and set
 125 * old_sha1 to the old value, or to null_sha1 to ensure the ref does
 126 * not exist before update.
 127 */
 128struct ref_update {
 129
 130        /*
 131         * If (flags & REF_HAVE_NEW), set the reference to this value:
 132         */
 133        struct object_id new_oid;
 134
 135        /*
 136         * If (flags & REF_HAVE_OLD), check that the reference
 137         * previously had this value:
 138         */
 139        struct object_id old_oid;
 140
 141        /*
 142         * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
 143         * REF_DELETING, REF_ISPRUNING, REF_LOG_ONLY,
 144         * REF_UPDATE_VIA_HEAD, REF_NEEDS_COMMIT, and
 145         * REF_DELETED_LOOSE:
 146         */
 147        unsigned int flags;
 148
 149        void *backend_data;
 150        unsigned int type;
 151        char *msg;
 152
 153        /*
 154         * If this ref_update was split off of a symref update via
 155         * split_symref_update(), then this member points at that
 156         * update. This is used for two purposes:
 157         * 1. When reporting errors, we report the refname under which
 158         *    the update was originally requested.
 159         * 2. When we read the old value of this reference, we
 160         *    propagate it back to its parent update for recording in
 161         *    the latter's reflog.
 162         */
 163        struct ref_update *parent_update;
 164
 165        const char refname[FLEX_ARRAY];
 166};
 167
 168int refs_read_raw_ref(struct ref_store *ref_store,
 169                      const char *refname, unsigned char *sha1,
 170                      struct strbuf *referent, unsigned int *type);
 171
 172/*
 173 * Write an error to `err` and return a nonzero value iff the same
 174 * refname appears multiple times in `refnames`. `refnames` must be
 175 * sorted on entry to this function.
 176 */
 177int ref_update_reject_duplicates(struct string_list *refnames,
 178                                 struct strbuf *err);
 179
 180/*
 181 * Add a ref_update with the specified properties to transaction, and
 182 * return a pointer to the new object. This function does not verify
 183 * that refname is well-formed. new_sha1 and old_sha1 are only
 184 * dereferenced if the REF_HAVE_NEW and REF_HAVE_OLD bits,
 185 * respectively, are set in flags.
 186 */
 187struct ref_update *ref_transaction_add_update(
 188                struct ref_transaction *transaction,
 189                const char *refname, unsigned int flags,
 190                const unsigned char *new_sha1,
 191                const unsigned char *old_sha1,
 192                const char *msg);
 193
 194/*
 195 * Transaction states.
 196 *
 197 * OPEN:   The transaction is initialized and new updates can still be
 198 *         added to it. An OPEN transaction can be prepared,
 199 *         committed, freed, or aborted (freeing and aborting an open
 200 *         transaction are equivalent).
 201 *
 202 * PREPARED: ref_transaction_prepare(), which locks all of the
 203 *         references involved in the update and checks that the
 204 *         update has no errors, has been called successfully for the
 205 *         transaction. A PREPARED transaction can be committed or
 206 *         aborted.
 207 *
 208 * CLOSED: The transaction is no longer active. A transaction becomes
 209 *         CLOSED if there is a failure while building the transaction
 210 *         or if a transaction is committed or aborted. A CLOSED
 211 *         transaction can only be freed.
 212 */
 213enum ref_transaction_state {
 214        REF_TRANSACTION_OPEN     = 0,
 215        REF_TRANSACTION_PREPARED = 1,
 216        REF_TRANSACTION_CLOSED   = 2
 217};
 218
 219/*
 220 * Data structure for holding a reference transaction, which can
 221 * consist of checks and updates to multiple references, carried out
 222 * as atomically as possible.  This structure is opaque to callers.
 223 */
 224struct ref_transaction {
 225        struct ref_store *ref_store;
 226        struct ref_update **updates;
 227        size_t alloc;
 228        size_t nr;
 229        enum ref_transaction_state state;
 230};
 231
 232/*
 233 * Check for entries in extras that are within the specified
 234 * directory, where dirname is a reference directory name including
 235 * the trailing slash (e.g., "refs/heads/foo/"). Ignore any
 236 * conflicting references that are found in skip. If there is a
 237 * conflicting reference, return its name.
 238 *
 239 * extras and skip must be sorted lists of reference names. Either one
 240 * can be NULL, signifying the empty list.
 241 */
 242const char *find_descendant_ref(const char *dirname,
 243                                const struct string_list *extras,
 244                                const struct string_list *skip);
 245
 246/*
 247 * Check whether an attempt to rename old_refname to new_refname would
 248 * cause a D/F conflict with any existing reference (other than
 249 * possibly old_refname). If there would be a conflict, emit an error
 250 * message and return false; otherwise, return true.
 251 *
 252 * Note that this function is not safe against all races with other
 253 * processes (though rename_ref() catches some races that might get by
 254 * this check).
 255 */
 256int refs_rename_ref_available(struct ref_store *refs,
 257                              const char *old_refname,
 258                              const char *new_refname);
 259
 260/* We allow "recursive" symbolic refs. Only within reason, though */
 261#define SYMREF_MAXDEPTH 5
 262
 263/* Include broken references in a do_for_each_ref*() iteration: */
 264#define DO_FOR_EACH_INCLUDE_BROKEN 0x01
 265
 266/*
 267 * Reference iterators
 268 *
 269 * A reference iterator encapsulates the state of an in-progress
 270 * iteration over references. Create an instance of `struct
 271 * ref_iterator` via one of the functions in this module.
 272 *
 273 * A freshly-created ref_iterator doesn't yet point at a reference. To
 274 * advance the iterator, call ref_iterator_advance(). If successful,
 275 * this sets the iterator's refname, oid, and flags fields to describe
 276 * the next reference and returns ITER_OK. The data pointed at by
 277 * refname and oid belong to the iterator; if you want to retain them
 278 * after calling ref_iterator_advance() again or calling
 279 * ref_iterator_abort(), you must make a copy. When the iteration has
 280 * been exhausted, ref_iterator_advance() releases any resources
 281 * assocated with the iteration, frees the ref_iterator object, and
 282 * returns ITER_DONE. If you want to abort the iteration early, call
 283 * ref_iterator_abort(), which also frees the ref_iterator object and
 284 * any associated resources. If there was an internal error advancing
 285 * to the next entry, ref_iterator_advance() aborts the iteration,
 286 * frees the ref_iterator, and returns ITER_ERROR.
 287 *
 288 * The reference currently being looked at can be peeled by calling
 289 * ref_iterator_peel(). This function is often faster than peel_ref(),
 290 * so it should be preferred when iterating over references.
 291 *
 292 * Putting it all together, a typical iteration looks like this:
 293 *
 294 *     int ok;
 295 *     struct ref_iterator *iter = ...;
 296 *
 297 *     while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
 298 *             if (want_to_stop_iteration()) {
 299 *                     ok = ref_iterator_abort(iter);
 300 *                     break;
 301 *             }
 302 *
 303 *             // Access information about the current reference:
 304 *             if (!(iter->flags & REF_ISSYMREF))
 305 *                     printf("%s is %s\n", iter->refname, oid_to_hex(&iter->oid));
 306 *
 307 *             // If you need to peel the reference:
 308 *             ref_iterator_peel(iter, &oid);
 309 *     }
 310 *
 311 *     if (ok != ITER_DONE)
 312 *             handle_error();
 313 */
 314struct ref_iterator {
 315        struct ref_iterator_vtable *vtable;
 316        const char *refname;
 317        const struct object_id *oid;
 318        unsigned int flags;
 319};
 320
 321/*
 322 * Advance the iterator to the first or next item and return ITER_OK.
 323 * If the iteration is exhausted, free the resources associated with
 324 * the ref_iterator and return ITER_DONE. On errors, free the iterator
 325 * resources and return ITER_ERROR. It is a bug to use ref_iterator or
 326 * call this function again after it has returned ITER_DONE or
 327 * ITER_ERROR.
 328 */
 329int ref_iterator_advance(struct ref_iterator *ref_iterator);
 330
 331/*
 332 * If possible, peel the reference currently being viewed by the
 333 * iterator. Return 0 on success.
 334 */
 335int ref_iterator_peel(struct ref_iterator *ref_iterator,
 336                      struct object_id *peeled);
 337
 338/*
 339 * End the iteration before it has been exhausted, freeing the
 340 * reference iterator and any associated resources and returning
 341 * ITER_DONE. If the abort itself failed, return ITER_ERROR.
 342 */
 343int ref_iterator_abort(struct ref_iterator *ref_iterator);
 344
 345/*
 346 * An iterator over nothing (its first ref_iterator_advance() call
 347 * returns ITER_DONE).
 348 */
 349struct ref_iterator *empty_ref_iterator_begin(void);
 350
 351/*
 352 * Return true iff ref_iterator is an empty_ref_iterator.
 353 */
 354int is_empty_ref_iterator(struct ref_iterator *ref_iterator);
 355
 356/*
 357 * Return an iterator that goes over each reference in `refs` for
 358 * which the refname begins with prefix. If trim is non-zero, then
 359 * trim that many characters off the beginning of each refname. flags
 360 * can be DO_FOR_EACH_INCLUDE_BROKEN to include broken references in
 361 * the iteration.
 362 */
 363struct ref_iterator *refs_ref_iterator_begin(
 364                struct ref_store *refs,
 365                const char *prefix, int trim, int flags);
 366
 367/*
 368 * A callback function used to instruct merge_ref_iterator how to
 369 * interleave the entries from iter0 and iter1. The function should
 370 * return one of the constants defined in enum iterator_selection. It
 371 * must not advance either of the iterators itself.
 372 *
 373 * The function must be prepared to handle the case that iter0 and/or
 374 * iter1 is NULL, which indicates that the corresponding sub-iterator
 375 * has been exhausted. Its return value must be consistent with the
 376 * current states of the iterators; e.g., it must not return
 377 * ITER_SKIP_1 if iter1 has already been exhausted.
 378 */
 379typedef enum iterator_selection ref_iterator_select_fn(
 380                struct ref_iterator *iter0, struct ref_iterator *iter1,
 381                void *cb_data);
 382
 383/*
 384 * Iterate over the entries from iter0 and iter1, with the values
 385 * interleaved as directed by the select function. The iterator takes
 386 * ownership of iter0 and iter1 and frees them when the iteration is
 387 * over.
 388 */
 389struct ref_iterator *merge_ref_iterator_begin(
 390                struct ref_iterator *iter0, struct ref_iterator *iter1,
 391                ref_iterator_select_fn *select, void *cb_data);
 392
 393/*
 394 * An iterator consisting of the union of the entries from front and
 395 * back. If there are entries common to the two sub-iterators, use the
 396 * one from front. Each iterator must iterate over its entries in
 397 * strcmp() order by refname for this to work.
 398 *
 399 * The new iterator takes ownership of its arguments and frees them
 400 * when the iteration is over. As a convenience to callers, if front
 401 * or back is an empty_ref_iterator, then abort that one immediately
 402 * and return the other iterator directly, without wrapping it.
 403 */
 404struct ref_iterator *overlay_ref_iterator_begin(
 405                struct ref_iterator *front, struct ref_iterator *back);
 406
 407/*
 408 * Wrap iter0, only letting through the references whose names start
 409 * with prefix. If trim is set, set iter->refname to the name of the
 410 * reference with that many characters trimmed off the front;
 411 * otherwise set it to the full refname. The new iterator takes over
 412 * ownership of iter0 and frees it when iteration is over. It makes
 413 * its own copy of prefix.
 414 *
 415 * As an convenience to callers, if prefix is the empty string and
 416 * trim is zero, this function returns iter0 directly, without
 417 * wrapping it.
 418 */
 419struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0,
 420                                               const char *prefix,
 421                                               int trim);
 422
 423/* Internal implementation of reference iteration: */
 424
 425/*
 426 * Base class constructor for ref_iterators. Initialize the
 427 * ref_iterator part of iter, setting its vtable pointer as specified.
 428 * This is meant to be called only by the initializers of derived
 429 * classes.
 430 */
 431void base_ref_iterator_init(struct ref_iterator *iter,
 432                            struct ref_iterator_vtable *vtable);
 433
 434/*
 435 * Base class destructor for ref_iterators. Destroy the ref_iterator
 436 * part of iter and shallow-free the object. This is meant to be
 437 * called only by the destructors of derived classes.
 438 */
 439void base_ref_iterator_free(struct ref_iterator *iter);
 440
 441/* Virtual function declarations for ref_iterators: */
 442
 443typedef int ref_iterator_advance_fn(struct ref_iterator *ref_iterator);
 444
 445typedef int ref_iterator_peel_fn(struct ref_iterator *ref_iterator,
 446                                 struct object_id *peeled);
 447
 448/*
 449 * Implementations of this function should free any resources specific
 450 * to the derived class, then call base_ref_iterator_free() to clean
 451 * up and free the ref_iterator object.
 452 */
 453typedef int ref_iterator_abort_fn(struct ref_iterator *ref_iterator);
 454
 455struct ref_iterator_vtable {
 456        ref_iterator_advance_fn *advance;
 457        ref_iterator_peel_fn *peel;
 458        ref_iterator_abort_fn *abort;
 459};
 460
 461/*
 462 * current_ref_iter is a performance hack: when iterating over
 463 * references using the for_each_ref*() functions, current_ref_iter is
 464 * set to the reference iterator before calling the callback function.
 465 * If the callback function calls peel_ref(), then peel_ref() first
 466 * checks whether the reference to be peeled is the one referred to by
 467 * the iterator (it usually is) and if so, asks the iterator for the
 468 * peeled version of the reference if it is available. This avoids a
 469 * refname lookup in a common case. current_ref_iter is set to NULL
 470 * when the iteration is over.
 471 */
 472extern struct ref_iterator *current_ref_iter;
 473
 474/*
 475 * The common backend for the for_each_*ref* functions. Call fn for
 476 * each reference in iter. If the iterator itself ever returns
 477 * ITER_ERROR, return -1. If fn ever returns a non-zero value, stop
 478 * the iteration and return that value. Otherwise, return 0. In any
 479 * case, free the iterator when done. This function is basically an
 480 * adapter between the callback style of reference iteration and the
 481 * iterator style.
 482 */
 483int do_for_each_ref_iterator(struct ref_iterator *iter,
 484                             each_ref_fn fn, void *cb_data);
 485
 486/*
 487 * Only include per-worktree refs in a do_for_each_ref*() iteration.
 488 * Normally this will be used with a files ref_store, since that's
 489 * where all reference backends will presumably store their
 490 * per-worktree refs.
 491 */
 492#define DO_FOR_EACH_PER_WORKTREE_ONLY 0x02
 493
 494struct ref_store;
 495
 496/* refs backends */
 497
 498/* ref_store_init flags */
 499#define REF_STORE_READ          (1 << 0)
 500#define REF_STORE_WRITE         (1 << 1) /* can perform update operations */
 501#define REF_STORE_ODB           (1 << 2) /* has access to object database */
 502#define REF_STORE_MAIN          (1 << 3)
 503#define REF_STORE_ALL_CAPS      (REF_STORE_READ | \
 504                                 REF_STORE_WRITE | \
 505                                 REF_STORE_ODB | \
 506                                 REF_STORE_MAIN)
 507
 508/*
 509 * Initialize the ref_store for the specified gitdir. These functions
 510 * should call base_ref_store_init() to initialize the shared part of
 511 * the ref_store and to record the ref_store for later lookup.
 512 */
 513typedef struct ref_store *ref_store_init_fn(const char *gitdir,
 514                                            unsigned int flags);
 515
 516typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
 517
 518typedef int ref_transaction_prepare_fn(struct ref_store *refs,
 519                                       struct ref_transaction *transaction,
 520                                       struct strbuf *err);
 521
 522typedef int ref_transaction_finish_fn(struct ref_store *refs,
 523                                      struct ref_transaction *transaction,
 524                                      struct strbuf *err);
 525
 526typedef int ref_transaction_abort_fn(struct ref_store *refs,
 527                                     struct ref_transaction *transaction,
 528                                     struct strbuf *err);
 529
 530typedef int ref_transaction_commit_fn(struct ref_store *refs,
 531                                      struct ref_transaction *transaction,
 532                                      struct strbuf *err);
 533
 534typedef int pack_refs_fn(struct ref_store *ref_store, unsigned int flags);
 535typedef int peel_ref_fn(struct ref_store *ref_store,
 536                        const char *refname, unsigned char *sha1);
 537typedef int create_symref_fn(struct ref_store *ref_store,
 538                             const char *ref_target,
 539                             const char *refs_heads_master,
 540                             const char *logmsg);
 541typedef int delete_refs_fn(struct ref_store *ref_store, const char *msg,
 542                           struct string_list *refnames, unsigned int flags);
 543typedef int rename_ref_fn(struct ref_store *ref_store,
 544                          const char *oldref, const char *newref,
 545                          const char *logmsg);
 546
 547/*
 548 * Iterate over the references in `ref_store` whose names start with
 549 * `prefix`. `prefix` is matched as a literal string, without regard
 550 * for path separators. If prefix is NULL or the empty string, iterate
 551 * over all references in `ref_store`.
 552 */
 553typedef struct ref_iterator *ref_iterator_begin_fn(
 554                struct ref_store *ref_store,
 555                const char *prefix, unsigned int flags);
 556
 557/* reflog functions */
 558
 559/*
 560 * Iterate over the references in the specified ref_store that have a
 561 * reflog. The refs are iterated over in arbitrary order.
 562 */
 563typedef struct ref_iterator *reflog_iterator_begin_fn(
 564                struct ref_store *ref_store);
 565
 566typedef int for_each_reflog_ent_fn(struct ref_store *ref_store,
 567                                   const char *refname,
 568                                   each_reflog_ent_fn fn,
 569                                   void *cb_data);
 570typedef int for_each_reflog_ent_reverse_fn(struct ref_store *ref_store,
 571                                           const char *refname,
 572                                           each_reflog_ent_fn fn,
 573                                           void *cb_data);
 574typedef int reflog_exists_fn(struct ref_store *ref_store, const char *refname);
 575typedef int create_reflog_fn(struct ref_store *ref_store, const char *refname,
 576                             int force_create, struct strbuf *err);
 577typedef int delete_reflog_fn(struct ref_store *ref_store, const char *refname);
 578typedef int reflog_expire_fn(struct ref_store *ref_store,
 579                             const char *refname, const unsigned char *sha1,
 580                             unsigned int flags,
 581                             reflog_expiry_prepare_fn prepare_fn,
 582                             reflog_expiry_should_prune_fn should_prune_fn,
 583                             reflog_expiry_cleanup_fn cleanup_fn,
 584                             void *policy_cb_data);
 585
 586/*
 587 * Read a reference from the specified reference store, non-recursively.
 588 * Set type to describe the reference, and:
 589 *
 590 * - If refname is the name of a normal reference, fill in sha1
 591 *   (leaving referent unchanged).
 592 *
 593 * - If refname is the name of a symbolic reference, write the full
 594 *   name of the reference to which it refers (e.g.
 595 *   "refs/heads/master") to referent and set the REF_ISSYMREF bit in
 596 *   type (leaving sha1 unchanged). The caller is responsible for
 597 *   validating that referent is a valid reference name.
 598 *
 599 * WARNING: refname might be used as part of a filename, so it is
 600 * important from a security standpoint that it be safe in the sense
 601 * of refname_is_safe(). Moreover, for symrefs this function sets
 602 * referent to whatever the repository says, which might not be a
 603 * properly-formatted or even safe reference name. NEITHER INPUT NOR
 604 * OUTPUT REFERENCE NAMES ARE VALIDATED WITHIN THIS FUNCTION.
 605 *
 606 * Return 0 on success. If the ref doesn't exist, set errno to ENOENT
 607 * and return -1. If the ref exists but is neither a symbolic ref nor
 608 * a sha1, it is broken; set REF_ISBROKEN in type, set errno to
 609 * EINVAL, and return -1. If there is another error reading the ref,
 610 * set errno appropriately and return -1.
 611 *
 612 * Backend-specific flags might be set in type as well, regardless of
 613 * outcome.
 614 *
 615 * It is OK for refname to point into referent. If so:
 616 *
 617 * - if the function succeeds with REF_ISSYMREF, referent will be
 618 *   overwritten and the memory formerly pointed to by it might be
 619 *   changed or even freed.
 620 *
 621 * - in all other cases, referent will be untouched, and therefore
 622 *   refname will still be valid and unchanged.
 623 */
 624typedef int read_raw_ref_fn(struct ref_store *ref_store,
 625                            const char *refname, unsigned char *sha1,
 626                            struct strbuf *referent, unsigned int *type);
 627
 628struct ref_storage_be {
 629        struct ref_storage_be *next;
 630        const char *name;
 631        ref_store_init_fn *init;
 632        ref_init_db_fn *init_db;
 633
 634        ref_transaction_prepare_fn *transaction_prepare;
 635        ref_transaction_finish_fn *transaction_finish;
 636        ref_transaction_abort_fn *transaction_abort;
 637        ref_transaction_commit_fn *initial_transaction_commit;
 638
 639        pack_refs_fn *pack_refs;
 640        peel_ref_fn *peel_ref;
 641        create_symref_fn *create_symref;
 642        delete_refs_fn *delete_refs;
 643        rename_ref_fn *rename_ref;
 644
 645        ref_iterator_begin_fn *iterator_begin;
 646        read_raw_ref_fn *read_raw_ref;
 647
 648        reflog_iterator_begin_fn *reflog_iterator_begin;
 649        for_each_reflog_ent_fn *for_each_reflog_ent;
 650        for_each_reflog_ent_reverse_fn *for_each_reflog_ent_reverse;
 651        reflog_exists_fn *reflog_exists;
 652        create_reflog_fn *create_reflog;
 653        delete_reflog_fn *delete_reflog;
 654        reflog_expire_fn *reflog_expire;
 655};
 656
 657extern struct ref_storage_be refs_be_files;
 658
 659/*
 660 * A representation of the reference store for the main repository or
 661 * a submodule. The ref_store instances for submodules are kept in a
 662 * linked list.
 663 */
 664struct ref_store {
 665        /* The backend describing this ref_store's storage scheme: */
 666        const struct ref_storage_be *be;
 667};
 668
 669/*
 670 * Fill in the generic part of refs and add it to our collection of
 671 * reference stores.
 672 */
 673void base_ref_store_init(struct ref_store *refs,
 674                         const struct ref_storage_be *be);
 675
 676#endif /* REFS_REFS_INTERNAL_H */