1 #ifndef REFS_REFS_INTERNAL_H
2 #define REFS_REFS_INTERNAL_H
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.
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).
14 #define REF_DELETING 0x02
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.
20 #define REF_ISPRUNING 0x04
23 * Used as a flag in ref_update::flags when the reference should be
24 * updated to new_sha1.
26 #define REF_HAVE_NEW 0x08
29 * Used as a flag in ref_update::flags when old_sha1 should be
32 #define REF_HAVE_OLD 0x10
35 * Used as a flag in ref_update::flags when the lockfile needs to be
38 #define REF_NEEDS_COMMIT 0x20
41 * 0x40 is REF_FORCE_CREATE_REFLOG, so skip it if you're adding a
42 * value to ref_update::flags
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.
50 #define REF_LOG_ONLY 0x80
53 * Internal flag, meaning that the containing ref_update was via an
56 #define REF_UPDATE_VIA_HEAD 0x100
59 * Used as a flag in ref_update::flags when the loose reference has
62 #define REF_DELETED_LOOSE 0x200
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().
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").
78 int refname_is_safe(const char *refname);
81 * Helper function: return true if refname, which has the specified
82 * oid and flags, can be resolved to an object in the database. If the
83 * referred-to object does not exist, emit a warning and return false.
85 int ref_resolves_to_object(const char *refname,
86 const struct object_id *oid,
90 /* object was peeled successfully: */
94 * object cannot be peeled because the named object (or an
95 * object referred to by a tag in the peel chain), does not
100 /* object cannot be peeled because it is not a tag: */
103 /* ref_entry contains no peeled value because it is a symref: */
107 * ref_entry cannot be peeled because it is broken (i.e., the
108 * symbolic reference cannot even be resolved to an object
115 * Peel the named object; i.e., if the object is a tag, resolve the
116 * tag recursively until a non-tag is found. If successful, store the
117 * result to sha1 and return PEEL_PEELED. If the object is not a tag
118 * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
119 * and leave sha1 unchanged.
121 enum peel_status peel_object(const unsigned char *name, unsigned char *sha1);
124 * Copy the reflog message msg to buf, which has been allocated sufficiently
125 * large, while cleaning up the whitespaces. Especially, convert LF to space,
126 * because reflog file is one line per entry.
128 int copy_reflog_msg(char *buf, const char *msg);
131 * Information needed for a single ref update. Set new_sha1 to the new
132 * value or to null_sha1 to delete the ref. To check the old value
133 * while the ref is locked, set (flags & REF_HAVE_OLD) and set
134 * old_sha1 to the old value, or to null_sha1 to ensure the ref does
135 * not exist before update.
140 * If (flags & REF_HAVE_NEW), set the reference to this value:
142 struct object_id new_oid;
145 * If (flags & REF_HAVE_OLD), check that the reference
146 * previously had this value:
148 struct object_id old_oid;
151 * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF,
152 * REF_DELETING, REF_ISPRUNING, REF_LOG_ONLY,
153 * REF_UPDATE_VIA_HEAD, REF_NEEDS_COMMIT, and
163 * If this ref_update was split off of a symref update via
164 * split_symref_update(), then this member points at that
165 * update. This is used for two purposes:
166 * 1. When reporting errors, we report the refname under which
167 * the update was originally requested.
168 * 2. When we read the old value of this reference, we
169 * propagate it back to its parent update for recording in
170 * the latter's reflog.
172 struct ref_update *parent_update;
174 const char refname[FLEX_ARRAY];
177 int refs_read_raw_ref(struct ref_store *ref_store,
178 const char *refname, unsigned char *sha1,
179 struct strbuf *referent, unsigned int *type);
182 * Write an error to `err` and return a nonzero value iff the same
183 * refname appears multiple times in `refnames`. `refnames` must be
184 * sorted on entry to this function.
186 int ref_update_reject_duplicates(struct string_list *refnames,
190 * Add a ref_update with the specified properties to transaction, and
191 * return a pointer to the new object. This function does not verify
192 * that refname is well-formed. new_sha1 and old_sha1 are only
193 * dereferenced if the REF_HAVE_NEW and REF_HAVE_OLD bits,
194 * respectively, are set in flags.
196 struct ref_update *ref_transaction_add_update(
197 struct ref_transaction *transaction,
198 const char *refname, unsigned int flags,
199 const unsigned char *new_sha1,
200 const unsigned char *old_sha1,
204 * Transaction states.
206 * OPEN: The transaction is initialized and new updates can still be
207 * added to it. An OPEN transaction can be prepared,
208 * committed, freed, or aborted (freeing and aborting an open
209 * transaction are equivalent).
211 * PREPARED: ref_transaction_prepare(), which locks all of the
212 * references involved in the update and checks that the
213 * update has no errors, has been called successfully for the
214 * transaction. A PREPARED transaction can be committed or
217 * CLOSED: The transaction is no longer active. A transaction becomes
218 * CLOSED if there is a failure while building the transaction
219 * or if a transaction is committed or aborted. A CLOSED
220 * transaction can only be freed.
222 enum ref_transaction_state {
223 REF_TRANSACTION_OPEN = 0,
224 REF_TRANSACTION_PREPARED = 1,
225 REF_TRANSACTION_CLOSED = 2
229 * Data structure for holding a reference transaction, which can
230 * consist of checks and updates to multiple references, carried out
231 * as atomically as possible. This structure is opaque to callers.
233 struct ref_transaction {
234 struct ref_store *ref_store;
235 struct ref_update **updates;
238 enum ref_transaction_state state;
242 * Check for entries in extras that are within the specified
243 * directory, where dirname is a reference directory name including
244 * the trailing slash (e.g., "refs/heads/foo/"). Ignore any
245 * conflicting references that are found in skip. If there is a
246 * conflicting reference, return its name.
248 * extras and skip must be sorted lists of reference names. Either one
249 * can be NULL, signifying the empty list.
251 const char *find_descendant_ref(const char *dirname,
252 const struct string_list *extras,
253 const struct string_list *skip);
256 * Check whether an attempt to rename old_refname to new_refname would
257 * cause a D/F conflict with any existing reference (other than
258 * possibly old_refname). If there would be a conflict, emit an error
259 * message and return false; otherwise, return true.
261 * Note that this function is not safe against all races with other
262 * processes (though rename_ref() catches some races that might get by
265 int refs_rename_ref_available(struct ref_store *refs,
266 const char *old_refname,
267 const char *new_refname);
269 /* We allow "recursive" symbolic refs. Only within reason, though */
270 #define SYMREF_MAXDEPTH 5
272 /* Include broken references in a do_for_each_ref*() iteration: */
273 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
276 * Reference iterators
278 * A reference iterator encapsulates the state of an in-progress
279 * iteration over references. Create an instance of `struct
280 * ref_iterator` via one of the functions in this module.
282 * A freshly-created ref_iterator doesn't yet point at a reference. To
283 * advance the iterator, call ref_iterator_advance(). If successful,
284 * this sets the iterator's refname, oid, and flags fields to describe
285 * the next reference and returns ITER_OK. The data pointed at by
286 * refname and oid belong to the iterator; if you want to retain them
287 * after calling ref_iterator_advance() again or calling
288 * ref_iterator_abort(), you must make a copy. When the iteration has
289 * been exhausted, ref_iterator_advance() releases any resources
290 * assocated with the iteration, frees the ref_iterator object, and
291 * returns ITER_DONE. If you want to abort the iteration early, call
292 * ref_iterator_abort(), which also frees the ref_iterator object and
293 * any associated resources. If there was an internal error advancing
294 * to the next entry, ref_iterator_advance() aborts the iteration,
295 * frees the ref_iterator, and returns ITER_ERROR.
297 * The reference currently being looked at can be peeled by calling
298 * ref_iterator_peel(). This function is often faster than peel_ref(),
299 * so it should be preferred when iterating over references.
301 * Putting it all together, a typical iteration looks like this:
304 * struct ref_iterator *iter = ...;
306 * while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
307 * if (want_to_stop_iteration()) {
308 * ok = ref_iterator_abort(iter);
312 * // Access information about the current reference:
313 * if (!(iter->flags & REF_ISSYMREF))
314 * printf("%s is %s\n", iter->refname, oid_to_hex(&iter->oid));
316 * // If you need to peel the reference:
317 * ref_iterator_peel(iter, &oid);
320 * if (ok != ITER_DONE)
323 struct ref_iterator {
324 struct ref_iterator_vtable *vtable;
326 const struct object_id *oid;
331 * Advance the iterator to the first or next item and return ITER_OK.
332 * If the iteration is exhausted, free the resources associated with
333 * the ref_iterator and return ITER_DONE. On errors, free the iterator
334 * resources and return ITER_ERROR. It is a bug to use ref_iterator or
335 * call this function again after it has returned ITER_DONE or
338 int ref_iterator_advance(struct ref_iterator *ref_iterator);
341 * If possible, peel the reference currently being viewed by the
342 * iterator. Return 0 on success.
344 int ref_iterator_peel(struct ref_iterator *ref_iterator,
345 struct object_id *peeled);
348 * End the iteration before it has been exhausted, freeing the
349 * reference iterator and any associated resources and returning
350 * ITER_DONE. If the abort itself failed, return ITER_ERROR.
352 int ref_iterator_abort(struct ref_iterator *ref_iterator);
355 * An iterator over nothing (its first ref_iterator_advance() call
356 * returns ITER_DONE).
358 struct ref_iterator *empty_ref_iterator_begin(void);
361 * Return true iff ref_iterator is an empty_ref_iterator.
363 int is_empty_ref_iterator(struct ref_iterator *ref_iterator);
366 * Return an iterator that goes over each reference in `refs` for
367 * which the refname begins with prefix. If trim is non-zero, then
368 * trim that many characters off the beginning of each refname. flags
369 * can be DO_FOR_EACH_INCLUDE_BROKEN to include broken references in
372 struct ref_iterator *refs_ref_iterator_begin(
373 struct ref_store *refs,
374 const char *prefix, int trim, int flags);
377 * A callback function used to instruct merge_ref_iterator how to
378 * interleave the entries from iter0 and iter1. The function should
379 * return one of the constants defined in enum iterator_selection. It
380 * must not advance either of the iterators itself.
382 * The function must be prepared to handle the case that iter0 and/or
383 * iter1 is NULL, which indicates that the corresponding sub-iterator
384 * has been exhausted. Its return value must be consistent with the
385 * current states of the iterators; e.g., it must not return
386 * ITER_SKIP_1 if iter1 has already been exhausted.
388 typedef enum iterator_selection ref_iterator_select_fn(
389 struct ref_iterator *iter0, struct ref_iterator *iter1,
393 * Iterate over the entries from iter0 and iter1, with the values
394 * interleaved as directed by the select function. The iterator takes
395 * ownership of iter0 and iter1 and frees them when the iteration is
398 struct ref_iterator *merge_ref_iterator_begin(
399 struct ref_iterator *iter0, struct ref_iterator *iter1,
400 ref_iterator_select_fn *select, void *cb_data);
403 * An iterator consisting of the union of the entries from front and
404 * back. If there are entries common to the two sub-iterators, use the
405 * one from front. Each iterator must iterate over its entries in
406 * strcmp() order by refname for this to work.
408 * The new iterator takes ownership of its arguments and frees them
409 * when the iteration is over. As a convenience to callers, if front
410 * or back is an empty_ref_iterator, then abort that one immediately
411 * and return the other iterator directly, without wrapping it.
413 struct ref_iterator *overlay_ref_iterator_begin(
414 struct ref_iterator *front, struct ref_iterator *back);
417 * Wrap iter0, only letting through the references whose names start
418 * with prefix. If trim is set, set iter->refname to the name of the
419 * reference with that many characters trimmed off the front;
420 * otherwise set it to the full refname. The new iterator takes over
421 * ownership of iter0 and frees it when iteration is over. It makes
422 * its own copy of prefix.
424 * As an convenience to callers, if prefix is the empty string and
425 * trim is zero, this function returns iter0 directly, without
428 struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0,
432 /* Internal implementation of reference iteration: */
435 * Base class constructor for ref_iterators. Initialize the
436 * ref_iterator part of iter, setting its vtable pointer as specified.
437 * This is meant to be called only by the initializers of derived
440 void base_ref_iterator_init(struct ref_iterator *iter,
441 struct ref_iterator_vtable *vtable);
444 * Base class destructor for ref_iterators. Destroy the ref_iterator
445 * part of iter and shallow-free the object. This is meant to be
446 * called only by the destructors of derived classes.
448 void base_ref_iterator_free(struct ref_iterator *iter);
450 /* Virtual function declarations for ref_iterators: */
452 typedef int ref_iterator_advance_fn(struct ref_iterator *ref_iterator);
454 typedef int ref_iterator_peel_fn(struct ref_iterator *ref_iterator,
455 struct object_id *peeled);
458 * Implementations of this function should free any resources specific
459 * to the derived class, then call base_ref_iterator_free() to clean
460 * up and free the ref_iterator object.
462 typedef int ref_iterator_abort_fn(struct ref_iterator *ref_iterator);
464 struct ref_iterator_vtable {
465 ref_iterator_advance_fn *advance;
466 ref_iterator_peel_fn *peel;
467 ref_iterator_abort_fn *abort;
471 * current_ref_iter is a performance hack: when iterating over
472 * references using the for_each_ref*() functions, current_ref_iter is
473 * set to the reference iterator before calling the callback function.
474 * If the callback function calls peel_ref(), then peel_ref() first
475 * checks whether the reference to be peeled is the one referred to by
476 * the iterator (it usually is) and if so, asks the iterator for the
477 * peeled version of the reference if it is available. This avoids a
478 * refname lookup in a common case. current_ref_iter is set to NULL
479 * when the iteration is over.
481 extern struct ref_iterator *current_ref_iter;
484 * The common backend for the for_each_*ref* functions. Call fn for
485 * each reference in iter. If the iterator itself ever returns
486 * ITER_ERROR, return -1. If fn ever returns a non-zero value, stop
487 * the iteration and return that value. Otherwise, return 0. In any
488 * case, free the iterator when done. This function is basically an
489 * adapter between the callback style of reference iteration and the
492 int do_for_each_ref_iterator(struct ref_iterator *iter,
493 each_ref_fn fn, void *cb_data);
496 * Only include per-worktree refs in a do_for_each_ref*() iteration.
497 * Normally this will be used with a files ref_store, since that's
498 * where all reference backends will presumably store their
501 #define DO_FOR_EACH_PER_WORKTREE_ONLY 0x02
507 /* ref_store_init flags */
508 #define REF_STORE_READ (1 << 0)
509 #define REF_STORE_WRITE (1 << 1) /* can perform update operations */
510 #define REF_STORE_ODB (1 << 2) /* has access to object database */
511 #define REF_STORE_MAIN (1 << 3)
512 #define REF_STORE_ALL_CAPS (REF_STORE_READ | \
518 * Initialize the ref_store for the specified gitdir. These functions
519 * should call base_ref_store_init() to initialize the shared part of
520 * the ref_store and to record the ref_store for later lookup.
522 typedef struct ref_store *ref_store_init_fn(const char *gitdir,
525 typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
527 typedef int ref_transaction_prepare_fn(struct ref_store *refs,
528 struct ref_transaction *transaction,
531 typedef int ref_transaction_finish_fn(struct ref_store *refs,
532 struct ref_transaction *transaction,
535 typedef int ref_transaction_abort_fn(struct ref_store *refs,
536 struct ref_transaction *transaction,
539 typedef int ref_transaction_commit_fn(struct ref_store *refs,
540 struct ref_transaction *transaction,
543 typedef int pack_refs_fn(struct ref_store *ref_store, unsigned int flags);
544 typedef int peel_ref_fn(struct ref_store *ref_store,
545 const char *refname, unsigned char *sha1);
546 typedef int create_symref_fn(struct ref_store *ref_store,
547 const char *ref_target,
548 const char *refs_heads_master,
550 typedef int delete_refs_fn(struct ref_store *ref_store, const char *msg,
551 struct string_list *refnames, unsigned int flags);
552 typedef int rename_ref_fn(struct ref_store *ref_store,
553 const char *oldref, const char *newref,
557 * Iterate over the references in `ref_store` whose names start with
558 * `prefix`. `prefix` is matched as a literal string, without regard
559 * for path separators. If prefix is NULL or the empty string, iterate
560 * over all references in `ref_store`.
562 typedef struct ref_iterator *ref_iterator_begin_fn(
563 struct ref_store *ref_store,
564 const char *prefix, unsigned int flags);
566 /* reflog functions */
569 * Iterate over the references in the specified ref_store that have a
570 * reflog. The refs are iterated over in arbitrary order.
572 typedef struct ref_iterator *reflog_iterator_begin_fn(
573 struct ref_store *ref_store);
575 typedef int for_each_reflog_ent_fn(struct ref_store *ref_store,
577 each_reflog_ent_fn fn,
579 typedef int for_each_reflog_ent_reverse_fn(struct ref_store *ref_store,
581 each_reflog_ent_fn fn,
583 typedef int reflog_exists_fn(struct ref_store *ref_store, const char *refname);
584 typedef int create_reflog_fn(struct ref_store *ref_store, const char *refname,
585 int force_create, struct strbuf *err);
586 typedef int delete_reflog_fn(struct ref_store *ref_store, const char *refname);
587 typedef int reflog_expire_fn(struct ref_store *ref_store,
588 const char *refname, const unsigned char *sha1,
590 reflog_expiry_prepare_fn prepare_fn,
591 reflog_expiry_should_prune_fn should_prune_fn,
592 reflog_expiry_cleanup_fn cleanup_fn,
593 void *policy_cb_data);
596 * Read a reference from the specified reference store, non-recursively.
597 * Set type to describe the reference, and:
599 * - If refname is the name of a normal reference, fill in sha1
600 * (leaving referent unchanged).
602 * - If refname is the name of a symbolic reference, write the full
603 * name of the reference to which it refers (e.g.
604 * "refs/heads/master") to referent and set the REF_ISSYMREF bit in
605 * type (leaving sha1 unchanged). The caller is responsible for
606 * validating that referent is a valid reference name.
608 * WARNING: refname might be used as part of a filename, so it is
609 * important from a security standpoint that it be safe in the sense
610 * of refname_is_safe(). Moreover, for symrefs this function sets
611 * referent to whatever the repository says, which might not be a
612 * properly-formatted or even safe reference name. NEITHER INPUT NOR
613 * OUTPUT REFERENCE NAMES ARE VALIDATED WITHIN THIS FUNCTION.
615 * Return 0 on success. If the ref doesn't exist, set errno to ENOENT
616 * and return -1. If the ref exists but is neither a symbolic ref nor
617 * a sha1, it is broken; set REF_ISBROKEN in type, set errno to
618 * EINVAL, and return -1. If there is another error reading the ref,
619 * set errno appropriately and return -1.
621 * Backend-specific flags might be set in type as well, regardless of
624 * It is OK for refname to point into referent. If so:
626 * - if the function succeeds with REF_ISSYMREF, referent will be
627 * overwritten and the memory formerly pointed to by it might be
628 * changed or even freed.
630 * - in all other cases, referent will be untouched, and therefore
631 * refname will still be valid and unchanged.
633 typedef int read_raw_ref_fn(struct ref_store *ref_store,
634 const char *refname, unsigned char *sha1,
635 struct strbuf *referent, unsigned int *type);
637 struct ref_storage_be {
638 struct ref_storage_be *next;
640 ref_store_init_fn *init;
641 ref_init_db_fn *init_db;
643 ref_transaction_prepare_fn *transaction_prepare;
644 ref_transaction_finish_fn *transaction_finish;
645 ref_transaction_abort_fn *transaction_abort;
646 ref_transaction_commit_fn *initial_transaction_commit;
648 pack_refs_fn *pack_refs;
649 peel_ref_fn *peel_ref;
650 create_symref_fn *create_symref;
651 delete_refs_fn *delete_refs;
652 rename_ref_fn *rename_ref;
654 ref_iterator_begin_fn *iterator_begin;
655 read_raw_ref_fn *read_raw_ref;
657 reflog_iterator_begin_fn *reflog_iterator_begin;
658 for_each_reflog_ent_fn *for_each_reflog_ent;
659 for_each_reflog_ent_reverse_fn *for_each_reflog_ent_reverse;
660 reflog_exists_fn *reflog_exists;
661 create_reflog_fn *create_reflog;
662 delete_reflog_fn *delete_reflog;
663 reflog_expire_fn *reflog_expire;
666 extern struct ref_storage_be refs_be_files;
667 extern struct ref_storage_be refs_be_packed;
670 * A representation of the reference store for the main repository or
671 * a submodule. The ref_store instances for submodules are kept in a
675 /* The backend describing this ref_store's storage scheme: */
676 const struct ref_storage_be *be;
680 * Fill in the generic part of refs and add it to our collection of
683 void base_ref_store_init(struct ref_store *refs,
684 const struct ref_storage_be *be);
686 #endif /* REFS_REFS_INTERNAL_H */