diff --git a/refs.c b/refs.c index 35d4e69687..d75a5dd53d 100644 --- a/refs.c +++ b/refs.c @@ -1672,6 +1672,23 @@ int refs_read_raw_ref(struct ref_store *ref_store, const char *refname, type, failure_errno); } +int refs_read_symbolic_ref(struct ref_store *ref_store, const char *refname, + struct strbuf *referent) +{ + struct object_id oid; + int ret, failure_errno = 0; + unsigned int type = 0; + + if (ref_store->be->read_symbolic_ref) + return ref_store->be->read_symbolic_ref(ref_store, refname, referent); + + ret = refs_read_raw_ref(ref_store, refname, &oid, referent, &type, &failure_errno); + if (ret || !(type & REF_ISSYMREF)) + return -1; + + return 0; +} + const char *refs_resolve_ref_unsafe(struct ref_store *refs, const char *refname, int resolve_flags, diff --git a/refs.h b/refs.h index 1ae12c410a..23479c7ee0 100644 --- a/refs.h +++ b/refs.h @@ -82,6 +82,9 @@ int read_ref_full(const char *refname, int resolve_flags, struct object_id *oid, int *flags); int read_ref(const char *refname, struct object_id *oid); +int refs_read_symbolic_ref(struct ref_store *ref_store, const char *refname, + struct strbuf *referent); + /* * Return 0 if a reference named refname could be created without * conflicting with the name of an existing reference. Otherwise, diff --git a/refs/debug.c b/refs/debug.c index 2b0771ca53..c590d37720 100644 --- a/refs/debug.c +++ b/refs/debug.c @@ -435,6 +435,7 @@ struct ref_storage_be refs_be_debug = { debug_ref_iterator_begin, debug_read_raw_ref, + NULL, debug_reflog_iterator_begin, debug_for_each_reflog_ent, diff --git a/refs/files-backend.c b/refs/files-backend.c index f59589d6cc..f3428a9f12 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -3286,6 +3286,7 @@ struct ref_storage_be refs_be_files = { files_ref_iterator_begin, files_read_raw_ref, + NULL, files_reflog_iterator_begin, files_for_each_reflog_ent, diff --git a/refs/packed-backend.c b/refs/packed-backend.c index 27dd8c3922..f56e2cc635 100644 --- a/refs/packed-backend.c +++ b/refs/packed-backend.c @@ -1684,6 +1684,7 @@ struct ref_storage_be refs_be_packed = { packed_ref_iterator_begin, packed_read_raw_ref, + NULL, packed_reflog_iterator_begin, packed_for_each_reflog_ent, diff --git a/refs/refs-internal.h b/refs/refs-internal.h index 6e15db3ca4..001ef15835 100644 --- a/refs/refs-internal.h +++ b/refs/refs-internal.h @@ -649,6 +649,21 @@ typedef int read_raw_ref_fn(struct ref_store *ref_store, const char *refname, struct object_id *oid, struct strbuf *referent, unsigned int *type, int *failure_errno); +/* + * Read a symbolic reference from the specified reference store. This function + * is optional: if not implemented by a backend, then `read_raw_ref_fn` is used + * to read the symbolcic reference instead. It is intended to be implemented + * only in case the backend can optimize the reading of symbolic references. + * + * Return 0 on success, or -1 on failure. `referent` will be set to the target + * of the symbolic reference on success. This function explicitly does not + * distinguish between error cases and the reference not being a symbolic + * reference to allow backends to optimize this operation in case symbolic and + * non-symbolic references are treated differently. + */ +typedef int read_symbolic_ref_fn(struct ref_store *ref_store, const char *refname, + struct strbuf *referent); + struct ref_storage_be { struct ref_storage_be *next; const char *name; @@ -668,6 +683,7 @@ struct ref_storage_be { ref_iterator_begin_fn *iterator_begin; read_raw_ref_fn *read_raw_ref; + read_symbolic_ref_fn *read_symbolic_ref; reflog_iterator_begin_fn *reflog_iterator_begin; for_each_reflog_ent_fn *for_each_reflog_ent;