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 /* object was peeled successfully: */
85 * object cannot be peeled because the named object (or an
86 * object referred to by a tag in the peel chain), does not
91 /* object cannot be peeled because it is not a tag: */
94 /* ref_entry contains no peeled value because it is a symref: */
98 * ref_entry cannot be peeled because it is broken (i.e., the
99 * symbolic reference cannot even be resolved to an object
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.
112 enum peel_status
peel_object(const unsigned char *name
, unsigned char *sha1
);
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.
119 int copy_reflog_msg(char *buf
, const char *msg
);
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.
131 * If (flags & REF_HAVE_NEW), set the reference to this value:
133 struct object_id new_oid
;
136 * If (flags & REF_HAVE_OLD), check that the reference
137 * previously had this value:
139 struct object_id old_oid
;
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
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.
163 struct ref_update
*parent_update
;
165 const char refname
[FLEX_ARRAY
];
168 int refs_read_raw_ref(struct ref_store
*ref_store
,
169 const char *refname
, unsigned char *sha1
,
170 struct strbuf
*referent
, unsigned int *type
);
173 * Add a ref_update with the specified properties to transaction, and
174 * return a pointer to the new object. This function does not verify
175 * that refname is well-formed. new_sha1 and old_sha1 are only
176 * dereferenced if the REF_HAVE_NEW and REF_HAVE_OLD bits,
177 * respectively, are set in flags.
179 struct ref_update
*ref_transaction_add_update(
180 struct ref_transaction
*transaction
,
181 const char *refname
, unsigned int flags
,
182 const unsigned char *new_sha1
,
183 const unsigned char *old_sha1
,
187 * Transaction states.
189 * OPEN: The transaction is initialized and new updates can still be
190 * added to it. An OPEN transaction can be prepared,
191 * committed, freed, or aborted (freeing and aborting an open
192 * transaction are equivalent).
194 * PREPARED: ref_transaction_prepare(), which locks all of the
195 * references involved in the update and checks that the
196 * update has no errors, has been called successfully for the
197 * transaction. A PREPARED transaction can be committed or
200 * CLOSED: The transaction is no longer active. A transaction becomes
201 * CLOSED if there is a failure while building the transaction
202 * or if a transaction is committed or aborted. A CLOSED
203 * transaction can only be freed.
205 enum ref_transaction_state
{
206 REF_TRANSACTION_OPEN
= 0,
207 REF_TRANSACTION_PREPARED
= 1,
208 REF_TRANSACTION_CLOSED
= 2
212 * Data structure for holding a reference transaction, which can
213 * consist of checks and updates to multiple references, carried out
214 * as atomically as possible. This structure is opaque to callers.
216 struct ref_transaction
{
217 struct ref_store
*ref_store
;
218 struct ref_update
**updates
;
221 enum ref_transaction_state state
;
225 * Check for entries in extras that are within the specified
226 * directory, where dirname is a reference directory name including
227 * the trailing slash (e.g., "refs/heads/foo/"). Ignore any
228 * conflicting references that are found in skip. If there is a
229 * conflicting reference, return its name.
231 * extras and skip must be sorted lists of reference names. Either one
232 * can be NULL, signifying the empty list.
234 const char *find_descendant_ref(const char *dirname
,
235 const struct string_list
*extras
,
236 const struct string_list
*skip
);
239 * Check whether an attempt to rename old_refname to new_refname would
240 * cause a D/F conflict with any existing reference (other than
241 * possibly old_refname). If there would be a conflict, emit an error
242 * message and return false; otherwise, return true.
244 * Note that this function is not safe against all races with other
245 * processes (though rename_ref() catches some races that might get by
248 int refs_rename_ref_available(struct ref_store
*refs
,
249 const char *old_refname
,
250 const char *new_refname
);
252 /* We allow "recursive" symbolic refs. Only within reason, though */
253 #define SYMREF_MAXDEPTH 5
255 /* Include broken references in a do_for_each_ref*() iteration: */
256 #define DO_FOR_EACH_INCLUDE_BROKEN 0x01
259 * Reference iterators
261 * A reference iterator encapsulates the state of an in-progress
262 * iteration over references. Create an instance of `struct
263 * ref_iterator` via one of the functions in this module.
265 * A freshly-created ref_iterator doesn't yet point at a reference. To
266 * advance the iterator, call ref_iterator_advance(). If successful,
267 * this sets the iterator's refname, oid, and flags fields to describe
268 * the next reference and returns ITER_OK. The data pointed at by
269 * refname and oid belong to the iterator; if you want to retain them
270 * after calling ref_iterator_advance() again or calling
271 * ref_iterator_abort(), you must make a copy. When the iteration has
272 * been exhausted, ref_iterator_advance() releases any resources
273 * assocated with the iteration, frees the ref_iterator object, and
274 * returns ITER_DONE. If you want to abort the iteration early, call
275 * ref_iterator_abort(), which also frees the ref_iterator object and
276 * any associated resources. If there was an internal error advancing
277 * to the next entry, ref_iterator_advance() aborts the iteration,
278 * frees the ref_iterator, and returns ITER_ERROR.
280 * The reference currently being looked at can be peeled by calling
281 * ref_iterator_peel(). This function is often faster than peel_ref(),
282 * so it should be preferred when iterating over references.
284 * Putting it all together, a typical iteration looks like this:
287 * struct ref_iterator *iter = ...;
289 * while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
290 * if (want_to_stop_iteration()) {
291 * ok = ref_iterator_abort(iter);
295 * // Access information about the current reference:
296 * if (!(iter->flags & REF_ISSYMREF))
297 * printf("%s is %s\n", iter->refname, oid_to_hex(&iter->oid));
299 * // If you need to peel the reference:
300 * ref_iterator_peel(iter, &oid);
303 * if (ok != ITER_DONE)
306 struct ref_iterator
{
307 struct ref_iterator_vtable
*vtable
;
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. flags
352 * can be DO_FOR_EACH_INCLUDE_BROKEN to include broken references in
355 struct ref_iterator
*refs_ref_iterator_begin(
356 struct ref_store
*refs
,
357 const char *prefix
, int trim
, int flags
);
360 * A callback function used to instruct merge_ref_iterator how to
361 * interleave the entries from iter0 and iter1. The function should
362 * return one of the constants defined in enum iterator_selection. It
363 * must not advance either of the iterators itself.
365 * The function must be prepared to handle the case that iter0 and/or
366 * iter1 is NULL, which indicates that the corresponding sub-iterator
367 * has been exhausted. Its return value must be consistent with the
368 * current states of the iterators; e.g., it must not return
369 * ITER_SKIP_1 if iter1 has already been exhausted.
371 typedef enum iterator_selection
ref_iterator_select_fn(
372 struct ref_iterator
*iter0
, struct ref_iterator
*iter1
,
376 * Iterate over the entries from iter0 and iter1, with the values
377 * interleaved as directed by the select function. The iterator takes
378 * ownership of iter0 and iter1 and frees them when the iteration is
381 struct ref_iterator
*merge_ref_iterator_begin(
382 struct ref_iterator
*iter0
, struct ref_iterator
*iter1
,
383 ref_iterator_select_fn
*select
, void *cb_data
);
386 * An iterator consisting of the union of the entries from front and
387 * back. If there are entries common to the two sub-iterators, use the
388 * one from front. Each iterator must iterate over its entries in
389 * strcmp() order by refname for this to work.
391 * The new iterator takes ownership of its arguments and frees them
392 * when the iteration is over. As a convenience to callers, if front
393 * or back is an empty_ref_iterator, then abort that one immediately
394 * and return the other iterator directly, without wrapping it.
396 struct ref_iterator
*overlay_ref_iterator_begin(
397 struct ref_iterator
*front
, struct ref_iterator
*back
);
400 * Wrap iter0, only letting through the references whose names start
401 * with prefix. If trim is set, set iter->refname to the name of the
402 * reference with that many characters trimmed off the front;
403 * otherwise set it to the full refname. The new iterator takes over
404 * ownership of iter0 and frees it when iteration is over. It makes
405 * its own copy of prefix.
407 * As an convenience to callers, if prefix is the empty string and
408 * trim is zero, this function returns iter0 directly, without
411 struct ref_iterator
*prefix_ref_iterator_begin(struct ref_iterator
*iter0
,
415 /* Internal implementation of reference iteration: */
418 * Base class constructor for ref_iterators. Initialize the
419 * ref_iterator part of iter, setting its vtable pointer as specified.
420 * This is meant to be called only by the initializers of derived
423 void base_ref_iterator_init(struct ref_iterator
*iter
,
424 struct ref_iterator_vtable
*vtable
);
427 * Base class destructor for ref_iterators. Destroy the ref_iterator
428 * part of iter and shallow-free the object. This is meant to be
429 * called only by the destructors of derived classes.
431 void base_ref_iterator_free(struct ref_iterator
*iter
);
433 /* Virtual function declarations for ref_iterators: */
435 typedef int ref_iterator_advance_fn(struct ref_iterator
*ref_iterator
);
437 typedef int ref_iterator_peel_fn(struct ref_iterator
*ref_iterator
,
438 struct object_id
*peeled
);
441 * Implementations of this function should free any resources specific
442 * to the derived class, then call base_ref_iterator_free() to clean
443 * up and free the ref_iterator object.
445 typedef int ref_iterator_abort_fn(struct ref_iterator
*ref_iterator
);
447 struct ref_iterator_vtable
{
448 ref_iterator_advance_fn
*advance
;
449 ref_iterator_peel_fn
*peel
;
450 ref_iterator_abort_fn
*abort
;
454 * current_ref_iter is a performance hack: when iterating over
455 * references using the for_each_ref*() functions, current_ref_iter is
456 * set to the reference iterator before calling the callback function.
457 * If the callback function calls peel_ref(), then peel_ref() first
458 * checks whether the reference to be peeled is the one referred to by
459 * the iterator (it usually is) and if so, asks the iterator for the
460 * peeled version of the reference if it is available. This avoids a
461 * refname lookup in a common case. current_ref_iter is set to NULL
462 * when the iteration is over.
464 extern struct ref_iterator
*current_ref_iter
;
467 * The common backend for the for_each_*ref* functions. Call fn for
468 * each reference in iter. If the iterator itself ever returns
469 * ITER_ERROR, return -1. If fn ever returns a non-zero value, stop
470 * the iteration and return that value. Otherwise, return 0. In any
471 * case, free the iterator when done. This function is basically an
472 * adapter between the callback style of reference iteration and the
475 int do_for_each_ref_iterator(struct ref_iterator
*iter
,
476 each_ref_fn fn
, void *cb_data
);
479 * Only include per-worktree refs in a do_for_each_ref*() iteration.
480 * Normally this will be used with a files ref_store, since that's
481 * where all reference backends will presumably store their
484 #define DO_FOR_EACH_PER_WORKTREE_ONLY 0x02
490 /* ref_store_init flags */
491 #define REF_STORE_READ (1 << 0)
492 #define REF_STORE_WRITE (1 << 1) /* can perform update operations */
493 #define REF_STORE_ODB (1 << 2) /* has access to object database */
494 #define REF_STORE_MAIN (1 << 3)
495 #define REF_STORE_ALL_CAPS (REF_STORE_READ | \
501 * Initialize the ref_store for the specified gitdir. These functions
502 * should call base_ref_store_init() to initialize the shared part of
503 * the ref_store and to record the ref_store for later lookup.
505 typedef struct ref_store
*ref_store_init_fn(const char *gitdir
,
508 typedef int ref_init_db_fn(struct ref_store
*refs
, struct strbuf
*err
);
510 typedef int ref_transaction_prepare_fn(struct ref_store
*refs
,
511 struct ref_transaction
*transaction
,
514 typedef int ref_transaction_finish_fn(struct ref_store
*refs
,
515 struct ref_transaction
*transaction
,
518 typedef int ref_transaction_abort_fn(struct ref_store
*refs
,
519 struct ref_transaction
*transaction
,
522 typedef int ref_transaction_commit_fn(struct ref_store
*refs
,
523 struct ref_transaction
*transaction
,
526 typedef int pack_refs_fn(struct ref_store
*ref_store
, unsigned int flags
);
527 typedef int peel_ref_fn(struct ref_store
*ref_store
,
528 const char *refname
, unsigned char *sha1
);
529 typedef int create_symref_fn(struct ref_store
*ref_store
,
530 const char *ref_target
,
531 const char *refs_heads_master
,
533 typedef int delete_refs_fn(struct ref_store
*ref_store
, const char *msg
,
534 struct string_list
*refnames
, unsigned int flags
);
535 typedef int rename_ref_fn(struct ref_store
*ref_store
,
536 const char *oldref
, const char *newref
,
540 * Iterate over the references in `ref_store` whose names start with
541 * `prefix`. `prefix` is matched as a literal string, without regard
542 * for path separators. If prefix is NULL or the empty string, iterate
543 * over all references in `ref_store`.
545 typedef struct ref_iterator
*ref_iterator_begin_fn(
546 struct ref_store
*ref_store
,
547 const char *prefix
, unsigned int flags
);
549 /* reflog functions */
552 * Iterate over the references in the specified ref_store that have a
553 * reflog. The refs are iterated over in arbitrary order.
555 typedef struct ref_iterator
*reflog_iterator_begin_fn(
556 struct ref_store
*ref_store
);
558 typedef int for_each_reflog_ent_fn(struct ref_store
*ref_store
,
560 each_reflog_ent_fn fn
,
562 typedef int for_each_reflog_ent_reverse_fn(struct ref_store
*ref_store
,
564 each_reflog_ent_fn fn
,
566 typedef int reflog_exists_fn(struct ref_store
*ref_store
, const char *refname
);
567 typedef int create_reflog_fn(struct ref_store
*ref_store
, const char *refname
,
568 int force_create
, struct strbuf
*err
);
569 typedef int delete_reflog_fn(struct ref_store
*ref_store
, const char *refname
);
570 typedef int reflog_expire_fn(struct ref_store
*ref_store
,
571 const char *refname
, const unsigned char *sha1
,
573 reflog_expiry_prepare_fn prepare_fn
,
574 reflog_expiry_should_prune_fn should_prune_fn
,
575 reflog_expiry_cleanup_fn cleanup_fn
,
576 void *policy_cb_data
);
579 * Read a reference from the specified reference store, non-recursively.
580 * Set type to describe the reference, and:
582 * - If refname is the name of a normal reference, fill in sha1
583 * (leaving referent unchanged).
585 * - If refname is the name of a symbolic reference, write the full
586 * name of the reference to which it refers (e.g.
587 * "refs/heads/master") to referent and set the REF_ISSYMREF bit in
588 * type (leaving sha1 unchanged). The caller is responsible for
589 * validating that referent is a valid reference name.
591 * WARNING: refname might be used as part of a filename, so it is
592 * important from a security standpoint that it be safe in the sense
593 * of refname_is_safe(). Moreover, for symrefs this function sets
594 * referent to whatever the repository says, which might not be a
595 * properly-formatted or even safe reference name. NEITHER INPUT NOR
596 * OUTPUT REFERENCE NAMES ARE VALIDATED WITHIN THIS FUNCTION.
598 * Return 0 on success. If the ref doesn't exist, set errno to ENOENT
599 * and return -1. If the ref exists but is neither a symbolic ref nor
600 * a sha1, it is broken; set REF_ISBROKEN in type, set errno to
601 * EINVAL, and return -1. If there is another error reading the ref,
602 * set errno appropriately and return -1.
604 * Backend-specific flags might be set in type as well, regardless of
607 * It is OK for refname to point into referent. If so:
609 * - if the function succeeds with REF_ISSYMREF, referent will be
610 * overwritten and the memory formerly pointed to by it might be
611 * changed or even freed.
613 * - in all other cases, referent will be untouched, and therefore
614 * refname will still be valid and unchanged.
616 typedef int read_raw_ref_fn(struct ref_store
*ref_store
,
617 const char *refname
, unsigned char *sha1
,
618 struct strbuf
*referent
, unsigned int *type
);
620 struct ref_storage_be
{
621 struct ref_storage_be
*next
;
623 ref_store_init_fn
*init
;
624 ref_init_db_fn
*init_db
;
626 ref_transaction_prepare_fn
*transaction_prepare
;
627 ref_transaction_finish_fn
*transaction_finish
;
628 ref_transaction_abort_fn
*transaction_abort
;
629 ref_transaction_commit_fn
*initial_transaction_commit
;
631 pack_refs_fn
*pack_refs
;
632 peel_ref_fn
*peel_ref
;
633 create_symref_fn
*create_symref
;
634 delete_refs_fn
*delete_refs
;
635 rename_ref_fn
*rename_ref
;
637 ref_iterator_begin_fn
*iterator_begin
;
638 read_raw_ref_fn
*read_raw_ref
;
640 reflog_iterator_begin_fn
*reflog_iterator_begin
;
641 for_each_reflog_ent_fn
*for_each_reflog_ent
;
642 for_each_reflog_ent_reverse_fn
*for_each_reflog_ent_reverse
;
643 reflog_exists_fn
*reflog_exists
;
644 create_reflog_fn
*create_reflog
;
645 delete_reflog_fn
*delete_reflog
;
646 reflog_expire_fn
*reflog_expire
;
649 extern struct ref_storage_be refs_be_files
;
652 * A representation of the reference store for the main repository or
653 * a submodule. The ref_store instances for submodules are kept in a
657 /* The backend describing this ref_store's storage scheme: */
658 const struct ref_storage_be
*be
;
662 * Fill in the generic part of refs and add it to our collection of
665 void base_ref_store_init(struct ref_store
*refs
,
666 const struct ref_storage_be
*be
);
668 #endif /* REFS_REFS_INTERNAL_H */