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Diffstat (limited to '')
| -rw-r--r-- | src/libutil/ref.h | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/src/libutil/ref.h b/src/libutil/ref.h new file mode 100644 index 0000000..2a3fd8d --- /dev/null +++ b/src/libutil/ref.h @@ -0,0 +1,91 @@ +/*- + * Copyright 2016 Vsevolod Stakhov + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +#ifndef REF_H_ +#define REF_H_ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + + +/** + * @file ref.h + * A set of macros to handle refcounts + */ + +typedef void (*ref_dtor_cb_t)(void *data); + +typedef struct ref_entry_s { + unsigned int refcount; + ref_dtor_cb_t dtor; +} ref_entry_t; + +#define REF_INIT(obj, dtor_cb) \ + do { \ + if ((obj) != NULL) { \ + (obj)->ref.refcount = 0; \ + (obj)->ref.dtor = (ref_dtor_cb_t) (dtor_cb); \ + } \ + } while (0) + +#define REF_INIT_RETAIN(obj, dtor_cb) \ + do { \ + if ((obj) != NULL) { \ + (obj)->ref.refcount = 1; \ + (obj)->ref.dtor = (ref_dtor_cb_t) (dtor_cb); \ + } \ + } while (0) + +#ifdef HAVE_ATOMIC_BUILTINS +#define REF_RETAIN_ATOMIC(obj) \ + do { \ + if ((obj) != NULL) { \ + __atomic_add_fetch(&(obj)->ref.refcount, 1, __ATOMIC_RELEASE); \ + } \ + } while (0) + +#define REF_RELEASE_ATOMIC(obj) \ + do { \ + if ((obj) != NULL) { \ + unsigned int _rc_priv = __atomic_sub_fetch(&(obj)->ref.refcount, 1, __ATOMIC_ACQ_REL); \ + if (_rc_priv == 0 && (obj)->ref.dtor) { \ + (obj)->ref.dtor(obj); \ + } \ + } \ + } while (0) + +#else +#define REF_RETAIN_ATOMIC REF_RETAIN +#define REF_RELEASE_ATOMIC REF_RELEASE_ATOMIC +#endif + +#define REF_RETAIN(obj) \ + do { \ + if ((obj) != NULL) { \ + (obj)->ref.refcount++; \ + } \ + } while (0) + +#define REF_RELEASE(obj) \ + do { \ + if ((obj) != NULL) { \ + if (--(obj)->ref.refcount == 0 && (obj)->ref.dtor) { \ + (obj)->ref.dtor(obj); \ + } \ + } \ + } while (0) + +#endif /* REF_H_ */ |