1 #ifndef REFS_REFS_INTERNAL_H
2 #define REFS_REFS_INTERNAL_H
8 struct ref_transaction;
11 * Data structures and functions for the internal use of the refs
12 * module. Code outside of the refs module should use only the public
13 * functions defined in "refs.h", and should *not* include this file.
17 * The following flags can appear in `ref_update::flags`. Their
18 * numerical values must not conflict with those of REF_NO_DEREF and
19 * REF_FORCE_CREATE_REFLOG, which are also stored in
20 * `ref_update::flags`.
24 * The reference should be updated to new_oid.
26 #define REF_HAVE_NEW (1 << 2)
29 * The current reference's value should be checked to make sure that
30 * it agrees with old_oid.
32 #define REF_HAVE_OLD (1 << 3)
35 * Used as a flag in ref_update::flags when we want to log a ref
36 * update but not actually perform it. This is used when a symbolic
37 * ref update is split up.
39 #define REF_LOG_ONLY (1 << 7)
42 * Return the length of time to retry acquiring a loose reference lock
43 * before giving up, in milliseconds:
45 long get_files_ref_lock_timeout_ms(void);
48 * Return true iff refname is minimally safe. "Safe" here means that
49 * deleting a loose reference by this name will not do any damage, for
50 * example by causing a file that is not a reference to be deleted.
51 * This function does not check that the reference name is legal; for
52 * that, use check_refname_format().
54 * A refname that starts with "refs/" is considered safe iff it
55 * doesn't contain any "." or ".." components or consecutive '/'
56 * characters, end with '/', or (on Windows) contain any '\'
57 * characters. Names that do not start with "refs/" are considered
58 * safe iff they consist entirely of upper case characters and '_'
59 * (like "HEAD" and "MERGE_HEAD" but not "config" or "FOO/BAR").
61 int refname_is_safe(const char *refname);
64 * Helper function: return true if refname, which has the specified
65 * oid and flags, can be resolved to an object in the database. If the
66 * referred-to object does not exist, emit a warning and return false.
68 int ref_resolves_to_object(const char *refname,
69 const struct object_id *oid,
73 /* object was peeled successfully: */
77 * object cannot be peeled because the named object (or an
78 * object referred to by a tag in the peel chain), does not
83 /* object cannot be peeled because it is not a tag: */
86 /* ref_entry contains no peeled value because it is a symref: */
90 * ref_entry cannot be peeled because it is broken (i.e., the
91 * symbolic reference cannot even be resolved to an object
98 * Peel the named object; i.e., if the object is a tag, resolve the
99 * tag recursively until a non-tag is found. If successful, store the
100 * result to oid and return PEEL_PEELED. If the object is not a tag
101 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
102 * and leave oid unchanged.
104 enum peel_status peel_object(const struct object_id *name, struct object_id *oid);
107 * Information needed for a single ref update. Set new_oid to the new
108 * value or to null_oid to delete the ref. To check the old value
109 * while the ref is locked, set (flags & REF_HAVE_OLD) and set old_oid
110 * to the old value, or to null_oid to ensure the ref does not exist
115 * If (flags & REF_HAVE_NEW), set the reference to this value
116 * (or delete it, if `new_oid` is `null_oid`).
118 struct object_id new_oid;
121 * If (flags & REF_HAVE_OLD), check that the reference
122 * previously had this value (or didn't previously exist, if
123 * `old_oid` is `null_oid`).
125 struct object_id old_oid;
128 * One or more of REF_NO_DEREF, REF_FORCE_CREATE_REFLOG,
129 * REF_HAVE_NEW, REF_HAVE_OLD, or backend-specific flags.
138 * If this ref_update was split off of a symref update via
139 * split_symref_update(), then this member points at that
140 * update. This is used for two purposes:
141 * 1. When reporting errors, we report the refname under which
142 * the update was originally requested.
143 * 2. When we read the old value of this reference, we
144 * propagate it back to its parent update for recording in
145 * the latter's reflog.
147 struct ref_update *parent_update;
149 const char refname[FLEX_ARRAY];
152 int refs_read_raw_ref(struct ref_store *ref_store,
153 const char *refname, struct object_id *oid,
154 struct strbuf *referent, unsigned int *type);
157 * Write an error to `err` and return a nonzero value iff the same
158 * refname appears multiple times in `refnames`. `refnames` must be
159 * sorted on entry to this function.
161 int ref_update_reject_duplicates(struct string_list *refnames,
165 * Add a ref_update with the specified properties to transaction, and
166 * return a pointer to the new object. This function does not verify
167 * that refname is well-formed. new_oid and old_oid are only
168 * dereferenced if the REF_HAVE_NEW and REF_HAVE_OLD bits,
169 * respectively, are set in flags.
171 struct ref_update *ref_transaction_add_update(
172 struct ref_transaction *transaction,
173 const char *refname, unsigned int flags,
174 const struct object_id *new_oid,
175 const struct object_id *old_oid,
179 * Transaction states.
181 * OPEN: The transaction is initialized and new updates can still be
182 * added to it. An OPEN transaction can be prepared,
183 * committed, freed, or aborted (freeing and aborting an open
184 * transaction are equivalent).
186 * PREPARED: ref_transaction_prepare(), which locks all of the
187 * references involved in the update and checks that the
188 * update has no errors, has been called successfully for the
189 * transaction. A PREPARED transaction can be committed or
192 * CLOSED: The transaction is no longer active. A transaction becomes
193 * CLOSED if there is a failure while building the transaction
194 * or if a transaction is committed or aborted. A CLOSED
195 * transaction can only be freed.
197 enum ref_transaction_state {
198 REF_TRANSACTION_OPEN = 0,
199 REF_TRANSACTION_PREPARED = 1,
200 REF_TRANSACTION_CLOSED = 2
204 * Data structure for holding a reference transaction, which can
205 * consist of checks and updates to multiple references, carried out
206 * as atomically as possible. This structure is opaque to callers.
208 struct ref_transaction {
209 struct ref_store *ref_store;
210 struct ref_update **updates;
213 enum ref_transaction_state state;
218 * Check for entries in extras that are within the specified
219 * directory, where dirname is a reference directory name including
220 * the trailing slash (e.g., "refs/heads/foo/"). Ignore any
221 * conflicting references that are found in skip. If there is a
222 * conflicting reference, return its name.
224 * extras and skip must be sorted lists of reference names. Either one
225 * can be NULL, signifying the empty list.
227 const char *find_descendant_ref(const char *dirname,
228 const struct string_list *extras,
229 const struct string_list *skip);
232 * Check whether an attempt to rename old_refname to new_refname would
233 * cause a D/F conflict with any existing reference (other than
234 * possibly old_refname). If there would be a conflict, emit an error
235 * message and return false; otherwise, return true.
237 * Note that this function is not safe against all races with other
238 * processes (though rename_ref() catches some races that might get by
241 int refs_rename_ref_available(struct ref_store *refs,
242 const char *old_refname,
243 const char *new_refname);
245 /* We allow "recursive" symbolic refs. Only within reason, though */
246 #define SYMREF_MAXDEPTH 5
248 /* Include broken references in a do_for_each_ref*() iteration: */
249 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
252 * Reference iterators
254 * A reference iterator encapsulates the state of an in-progress
255 * iteration over references. Create an instance of `struct
256 * ref_iterator` via one of the functions in this module.
258 * A freshly-created ref_iterator doesn't yet point at a reference. To
259 * advance the iterator, call ref_iterator_advance(). If successful,
260 * this sets the iterator's refname, oid, and flags fields to describe
261 * the next reference and returns ITER_OK. The data pointed at by
262 * refname and oid belong to the iterator; if you want to retain them
263 * after calling ref_iterator_advance() again or calling
264 * ref_iterator_abort(), you must make a copy. When the iteration has
265 * been exhausted, ref_iterator_advance() releases any resources
266 * associated with the iteration, frees the ref_iterator object, and
267 * returns ITER_DONE. If you want to abort the iteration early, call
268 * ref_iterator_abort(), which also frees the ref_iterator object and
269 * any associated resources. If there was an internal error advancing
270 * to the next entry, ref_iterator_advance() aborts the iteration,
271 * frees the ref_iterator, and returns ITER_ERROR.
273 * The reference currently being looked at can be peeled by calling
274 * ref_iterator_peel(). This function is often faster than peel_ref(),
275 * so it should be preferred when iterating over references.
277 * Putting it all together, a typical iteration looks like this:
280 * struct ref_iterator *iter = ...;
282 * while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
283 * if (want_to_stop_iteration()) {
284 * ok = ref_iterator_abort(iter);
288 * // Access information about the current reference:
289 * if (!(iter->flags & REF_ISSYMREF))
290 * printf("%s is %s\n", iter->refname, oid_to_hex(iter->oid));
292 * // If you need to peel the reference:
293 * ref_iterator_peel(iter, &oid);
296 * if (ok != ITER_DONE)
299 struct ref_iterator {
300 struct ref_iterator_vtable *vtable;
303 * Does this `ref_iterator` iterate over references in order
306 unsigned int ordered : 1;
309 const struct object_id *oid;
314 * Advance the iterator to the first or next item and return ITER_OK.
315 * If the iteration is exhausted, free the resources associated with
316 * the ref_iterator and return ITER_DONE. On errors, free the iterator
317 * resources and return ITER_ERROR. It is a bug to use ref_iterator or
318 * call this function again after it has returned ITER_DONE or
321 int ref_iterator_advance(struct ref_iterator *ref_iterator);
324 * If possible, peel the reference currently being viewed by the
325 * iterator. Return 0 on success.
327 int ref_iterator_peel(struct ref_iterator *ref_iterator,
328 struct object_id *peeled);
331 * End the iteration before it has been exhausted, freeing the
332 * reference iterator and any associated resources and returning
333 * ITER_DONE. If the abort itself failed, return ITER_ERROR.
335 int ref_iterator_abort(struct ref_iterator *ref_iterator);
338 * An iterator over nothing (its first ref_iterator_advance() call
339 * returns ITER_DONE).
341 struct ref_iterator *empty_ref_iterator_begin(void);
344 * Return true iff ref_iterator is an empty_ref_iterator.
346 int is_empty_ref_iterator(struct ref_iterator *ref_iterator);
349 * Return an iterator that goes over each reference in `refs` for
350 * which the refname begins with prefix. If trim is non-zero, then
351 * trim that many characters off the beginning of each refname.
352 * The output is ordered by refname. The following flags are supported:
354 * DO_FOR_EACH_INCLUDE_BROKEN: include broken references in
357 * DO_FOR_EACH_PER_WORKTREE_ONLY: only produce REF_TYPE_PER_WORKTREE refs.
359 struct ref_iterator *refs_ref_iterator_begin(
360 struct ref_store *refs,
361 const char *prefix, int trim, int flags);
364 * A callback function used to instruct merge_ref_iterator how to
365 * interleave the entries from iter0 and iter1. The function should
366 * return one of the constants defined in enum iterator_selection. It
367 * must not advance either of the iterators itself.
369 * The function must be prepared to handle the case that iter0 and/or
370 * iter1 is NULL, which indicates that the corresponding sub-iterator
371 * has been exhausted. Its return value must be consistent with the
372 * current states of the iterators; e.g., it must not return
373 * ITER_SKIP_1 if iter1 has already been exhausted.
375 typedef enum iterator_selection ref_iterator_select_fn(
376 struct ref_iterator *iter0, struct ref_iterator *iter1,
380 * Iterate over the entries from iter0 and iter1, with the values
381 * interleaved as directed by the select function. The iterator takes
382 * ownership of iter0 and iter1 and frees them when the iteration is
383 * over. A derived class should set `ordered` to 1 or 0 based on
384 * whether it generates its output in order by reference name.
386 struct ref_iterator *merge_ref_iterator_begin(
388 struct ref_iterator *iter0, struct ref_iterator *iter1,
389 ref_iterator_select_fn *select, void *cb_data);
392 * An iterator consisting of the union of the entries from front and
393 * back. If there are entries common to the two sub-iterators, use the
394 * one from front. Each iterator must iterate over its entries in
395 * strcmp() order by refname for this to work.
397 * The new iterator takes ownership of its arguments and frees them
398 * when the iteration is over. As a convenience to callers, if front
399 * or back is an empty_ref_iterator, then abort that one immediately
400 * and return the other iterator directly, without wrapping it.
402 struct ref_iterator *overlay_ref_iterator_begin(
403 struct ref_iterator *front, struct ref_iterator *back);
406 * Wrap iter0, only letting through the references whose names start
407 * with prefix. If trim is set, set iter->refname to the name of the
408 * reference with that many characters trimmed off the front;
409 * otherwise set it to the full refname. The new iterator takes over
410 * ownership of iter0 and frees it when iteration is over. It makes
411 * its own copy of prefix.
413 * As an convenience to callers, if prefix is the empty string and
414 * trim is zero, this function returns iter0 directly, without
417 * The resulting ref_iterator is ordered if iter0 is.
419 struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0,
423 /* Internal implementation of reference iteration: */
426 * Base class constructor for ref_iterators. Initialize the
427 * ref_iterator part of iter, setting its vtable pointer as specified.
428 * `ordered` should be set to 1 if the iterator will iterate over
429 * references in order by refname; otherwise it should be set to 0.
430 * This is meant to be called only by the initializers of derived
433 void base_ref_iterator_init(struct ref_iterator *iter,
434 struct ref_iterator_vtable *vtable,
438 * Base class destructor for ref_iterators. Destroy the ref_iterator
439 * part of iter and shallow-free the object. This is meant to be
440 * called only by the destructors of derived classes.
442 void base_ref_iterator_free(struct ref_iterator *iter);
444 /* Virtual function declarations for ref_iterators: */
447 * backend-specific implementation of ref_iterator_advance. For symrefs, the
448 * function should set REF_ISSYMREF, and it should also dereference the symref
449 * to provide the OID referent. If DO_FOR_EACH_INCLUDE_BROKEN is set, symrefs
450 * with non-existent referents and refs pointing to non-existent object names
451 * should also be returned. If DO_FOR_EACH_PER_WORKTREE_ONLY, only
452 * REF_TYPE_PER_WORKTREE refs should be returned.
454 typedef int ref_iterator_advance_fn(struct ref_iterator *ref_iterator);
456 typedef int ref_iterator_peel_fn(struct ref_iterator *ref_iterator,
457 struct object_id *peeled);
460 * Implementations of this function should free any resources specific
461 * to the derived class, then call base_ref_iterator_free() to clean
462 * up and free the ref_iterator object.
464 typedef int ref_iterator_abort_fn(struct ref_iterator *ref_iterator);
466 struct ref_iterator_vtable {
467 ref_iterator_advance_fn *advance;
468 ref_iterator_peel_fn *peel;
469 ref_iterator_abort_fn *abort;
473 * current_ref_iter is a performance hack: when iterating over
474 * references using the for_each_ref*() functions, current_ref_iter is
475 * set to the reference iterator before calling the callback function.
476 * If the callback function calls peel_ref(), then peel_ref() first
477 * checks whether the reference to be peeled is the one referred to by
478 * the iterator (it usually is) and if so, asks the iterator for the
479 * peeled version of the reference if it is available. This avoids a
480 * refname lookup in a common case. current_ref_iter is set to NULL
481 * when the iteration is over.
483 extern struct ref_iterator *current_ref_iter;
486 * The common backend for the for_each_*ref* functions. Call fn for
487 * each reference in iter. If the iterator itself ever returns
488 * ITER_ERROR, return -1. If fn ever returns a non-zero value, stop
489 * the iteration and return that value. Otherwise, return 0. In any
490 * case, free the iterator when done. This function is basically an
491 * adapter between the callback style of reference iteration and the
494 int do_for_each_repo_ref_iterator(struct repository *r,
495 struct ref_iterator *iter,
496 each_repo_ref_fn fn, void *cb_data);
499 * Only include per-worktree refs in a do_for_each_ref*() iteration.
500 * Normally this will be used with a files ref_store, since that's
501 * where all reference backends will presumably store their
504 #define DO_FOR_EACH_PER_WORKTREE_ONLY 0x02
510 /* ref_store_init flags */
511 #define REF_STORE_READ (1 << 0)
512 #define REF_STORE_WRITE (1 << 1) /* can perform update operations */
513 #define REF_STORE_ODB (1 << 2) /* has access to object database */
514 #define REF_STORE_MAIN (1 << 3)
515 #define REF_STORE_ALL_CAPS (REF_STORE_READ | \
521 * Initialize the ref_store for the specified gitdir. These functions
522 * should call base_ref_store_init() to initialize the shared part of
523 * the ref_store and to record the ref_store for later lookup.
525 typedef struct ref_store *ref_store_init_fn(const char *gitdir,
528 typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
530 typedef int ref_transaction_prepare_fn(struct ref_store *refs,
531 struct ref_transaction *transaction,
534 typedef int ref_transaction_finish_fn(struct ref_store *refs,
535 struct ref_transaction *transaction,
538 typedef int ref_transaction_abort_fn(struct ref_store *refs,
539 struct ref_transaction *transaction,
542 typedef int ref_transaction_commit_fn(struct ref_store *refs,
543 struct ref_transaction *transaction,
546 typedef int pack_refs_fn(struct ref_store *ref_store, unsigned int flags);
547 typedef int create_symref_fn(struct ref_store *ref_store,
548 const char *ref_target,
549 const char *refs_heads_master,
551 typedef int delete_refs_fn(struct ref_store *ref_store, const char *msg,
552 struct string_list *refnames, unsigned int flags);
553 typedef int rename_ref_fn(struct ref_store *ref_store,
554 const char *oldref, const char *newref,
556 typedef int copy_ref_fn(struct ref_store *ref_store,
557 const char *oldref, const char *newref,
561 * Iterate over the references in `ref_store` whose names start with
562 * `prefix`. `prefix` is matched as a literal string, without regard
563 * for path separators. If prefix is NULL or the empty string, iterate
564 * over all references in `ref_store`. The output is ordered by
567 typedef struct ref_iterator *ref_iterator_begin_fn(
568 struct ref_store *ref_store,
569 const char *prefix, unsigned int flags);
571 /* reflog functions */
574 * Iterate over the references in the specified ref_store that have a
575 * reflog. The refs are iterated over in arbitrary order.
577 typedef struct ref_iterator *reflog_iterator_begin_fn(
578 struct ref_store *ref_store);
580 typedef int for_each_reflog_ent_fn(struct ref_store *ref_store,
582 each_reflog_ent_fn fn,
584 typedef int for_each_reflog_ent_reverse_fn(struct ref_store *ref_store,
586 each_reflog_ent_fn fn,
588 typedef int reflog_exists_fn(struct ref_store *ref_store, const char *refname);
589 typedef int create_reflog_fn(struct ref_store *ref_store, const char *refname,
590 int force_create, struct strbuf *err);
591 typedef int delete_reflog_fn(struct ref_store *ref_store, const char *refname);
592 typedef int reflog_expire_fn(struct ref_store *ref_store,
593 const char *refname, const struct object_id *oid,
595 reflog_expiry_prepare_fn prepare_fn,
596 reflog_expiry_should_prune_fn should_prune_fn,
597 reflog_expiry_cleanup_fn cleanup_fn,
598 void *policy_cb_data);
601 * Read a reference from the specified reference store, non-recursively.
602 * Set type to describe the reference, and:
604 * - If refname is the name of a normal reference, fill in oid
605 * (leaving referent unchanged).
607 * - If refname is the name of a symbolic reference, write the full
608 * name of the reference to which it refers (e.g.
609 * "refs/heads/master") to referent and set the REF_ISSYMREF bit in
610 * type (leaving oid unchanged). The caller is responsible for
611 * validating that referent is a valid reference name.
613 * WARNING: refname might be used as part of a filename, so it is
614 * important from a security standpoint that it be safe in the sense
615 * of refname_is_safe(). Moreover, for symrefs this function sets
616 * referent to whatever the repository says, which might not be a
617 * properly-formatted or even safe reference name. NEITHER INPUT NOR
618 * OUTPUT REFERENCE NAMES ARE VALIDATED WITHIN THIS FUNCTION.
620 * Return 0 on success. If the ref doesn't exist, set errno to ENOENT
621 * and return -1. If the ref exists but is neither a symbolic ref nor
622 * an object ID, it is broken; set REF_ISBROKEN in type, set errno to
623 * EINVAL, and return -1. If there is another error reading the ref,
624 * set errno appropriately and return -1.
626 * Backend-specific flags might be set in type as well, regardless of
629 * It is OK for refname to point into referent. If so:
631 * - if the function succeeds with REF_ISSYMREF, referent will be
632 * overwritten and the memory formerly pointed to by it might be
633 * changed or even freed.
635 * - in all other cases, referent will be untouched, and therefore
636 * refname will still be valid and unchanged.
638 typedef int read_raw_ref_fn(struct ref_store *ref_store,
639 const char *refname, struct object_id *oid,
640 struct strbuf *referent, unsigned int *type);
642 struct ref_storage_be {
643 struct ref_storage_be *next;
645 ref_store_init_fn *init;
646 ref_init_db_fn *init_db;
648 ref_transaction_prepare_fn *transaction_prepare;
649 ref_transaction_finish_fn *transaction_finish;
650 ref_transaction_abort_fn *transaction_abort;
651 ref_transaction_commit_fn *initial_transaction_commit;
653 pack_refs_fn *pack_refs;
654 create_symref_fn *create_symref;
655 delete_refs_fn *delete_refs;
656 rename_ref_fn *rename_ref;
657 copy_ref_fn *copy_ref;
659 ref_iterator_begin_fn *iterator_begin;
660 read_raw_ref_fn *read_raw_ref;
662 reflog_iterator_begin_fn *reflog_iterator_begin;
663 for_each_reflog_ent_fn *for_each_reflog_ent;
664 for_each_reflog_ent_reverse_fn *for_each_reflog_ent_reverse;
665 reflog_exists_fn *reflog_exists;
666 create_reflog_fn *create_reflog;
667 delete_reflog_fn *delete_reflog;
668 reflog_expire_fn *reflog_expire;
671 extern struct ref_storage_be refs_be_files;
672 extern struct ref_storage_be refs_be_packed;
675 * A representation of the reference store for the main repository or
676 * a submodule. The ref_store instances for submodules are kept in a
677 * hash map; see get_submodule_ref_store() for more info.
680 /* The backend describing this ref_store's storage scheme: */
681 const struct ref_storage_be *be;
683 /* The gitdir that this ref_store applies to: */
688 * Parse contents of a loose ref file.
690 int parse_loose_ref_contents(const char *buf, struct object_id *oid,
691 struct strbuf *referent, unsigned int *type);
694 * Fill in the generic part of refs and add it to our collection of
697 void base_ref_store_init(struct ref_store *refs,
698 const struct ref_storage_be *be);
701 * Support GIT_TRACE_REFS by optionally wrapping the given ref_store instance.
703 struct ref_store *maybe_debug_wrap_ref_store(const char *gitdir, struct ref_store *store);
705 #endif /* REFS_REFS_INTERNAL_H */