| /* |
| * Copyright (c) 2013, Google, Inc. All rights reserved |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining |
| * a copy of this software and associated documentation files |
| * (the "Software"), to deal in the Software without restriction, |
| * including without limitation the rights to use, copy, modify, merge, |
| * publish, distribute, sublicense, and/or sell copies of the Software, |
| * and to permit persons to whom the Software is furnished to do so, |
| * subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be |
| * included in all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
| * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| */ |
| |
| #ifndef __REFLIST_H |
| #define __REFLIST_H |
| |
| #include <assert.h> |
| #include <lk/compiler.h> |
| #include <lk/list.h> |
| |
| struct obj_ref { |
| struct list_node ref_node; |
| }; |
| |
| struct obj { |
| struct list_node ref_list; |
| }; |
| |
| typedef void (*obj_destroy_func)(struct obj* obj); |
| |
| #define OBJ_REF_INITIAL_VALUE(r) \ |
| { .ref_node = LIST_INITIAL_CLEARED_VALUE } |
| |
| static inline __ALWAYS_INLINE void obj_ref_init(struct obj_ref* ref) { |
| *ref = (struct obj_ref)OBJ_REF_INITIAL_VALUE(*ref); |
| } |
| |
| static inline __ALWAYS_INLINE bool obj_ref_active(struct obj_ref* ref) { |
| return list_in_list(&ref->ref_node); |
| } |
| |
| static inline __ALWAYS_INLINE void obj_init(struct obj* obj, |
| struct obj_ref* ref) { |
| list_initialize(&obj->ref_list); |
| list_add_tail(&obj->ref_list, &ref->ref_node); |
| } |
| |
| static inline __ALWAYS_INLINE bool obj_has_ref(struct obj* obj) { |
| return !list_is_empty(&obj->ref_list); |
| } |
| |
| static inline __ALWAYS_INLINE bool obj_has_only_ref(struct obj* obj, |
| struct obj_ref* ref) { |
| assert(obj_has_ref(obj)); |
| assert(list_in_list(&ref->ref_node)); |
| struct list_node* head = list_peek_head(&obj->ref_list); |
| struct list_node* tail = list_peek_tail(&obj->ref_list); |
| if (head == tail) { |
| assert(head == &ref->ref_node); |
| return head == &ref->ref_node; |
| } |
| return false; |
| } |
| |
| /* |
| * Only use if you are intentionally reusing a possibly unreferenced |
| * object. A cache is an example of this use case, where the destroy |
| * callback may not actually free the object, and the code may wish to |
| * reuse it by adding a reference after it hits zero. |
| */ |
| static inline __ALWAYS_INLINE void obj_add_ref_allow_unreferenced_obj( |
| struct obj* obj, struct obj_ref* ref) { |
| assert(!list_in_list(&ref->ref_node)); |
| list_add_tail(&obj->ref_list, &ref->ref_node); |
| } |
| |
| static inline __ALWAYS_INLINE void obj_add_ref(struct obj* obj, |
| struct obj_ref* ref) { |
| assert(obj_has_ref(obj)); |
| obj_add_ref_allow_unreferenced_obj(obj, ref); |
| } |
| |
| static inline __ALWAYS_INLINE bool obj_del_ref(struct obj* obj, |
| struct obj_ref* ref, |
| obj_destroy_func destroy) { |
| bool dead; |
| |
| assert(list_in_list(&ref->ref_node)); |
| |
| list_delete(&ref->ref_node); |
| dead = list_is_empty(&obj->ref_list); |
| if (dead && destroy) |
| destroy(obj); |
| return dead; |
| } |
| |
| static inline __ALWAYS_INLINE void obj_ref_transfer(struct obj_ref* dst, |
| struct obj_ref* src) { |
| struct list_node* prev; |
| |
| assert(!list_in_list(&dst->ref_node)); |
| assert(list_in_list(&src->ref_node)); |
| |
| prev = src->ref_node.prev; |
| list_delete(&src->ref_node); |
| list_add_after(prev, &dst->ref_node); |
| } |
| |
| #endif |