1 /* 2 * Copyright (c) 2021 Huawei Device Co., Ltd. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16 #ifndef UTILS_RWLOCK_H 17 #define UTILS_RWLOCK_H 18 19 #include <atomic> 20 #include <thread> 21 22 #include "nocopyable.h" 23 24 namespace OHOS { 25 namespace Utils { 26 27 class RWLock : NoCopyable { 28 public: 29 enum LockStatus { 30 LOCK_STATUS_WRITE = -1, 31 LOCK_STATUS_FREE = 0, 32 }; 33 RWLock()34 RWLock() : RWLock(true) {} 35 explicit RWLock(bool writeFirst); ~RWLock()36 virtual ~RWLock() {} 37 38 void LockRead(); 39 void UnLockRead(); 40 41 void LockWrite(); 42 void UnLockWrite(); 43 44 private: 45 bool writeFirst_; 46 std::thread::id writeThreadID_; 47 48 // Resource lock counter, -1 is write state, 0 is free state, and greater than 0 is shared read state 49 std::atomic_int lockCount_; 50 51 // Thread counter waiting for write lock 52 std::atomic_uint writeWaitCount_; 53 }; 54 55 template <typename RWLockable> 56 class UniqueWriteGuard : NoCopyable { 57 public: UniqueWriteGuard(RWLockable & rwLockable)58 explicit UniqueWriteGuard(RWLockable &rwLockable) 59 : rwLockable_(rwLockable) 60 { 61 rwLockable_.LockWrite(); 62 } 63 ~UniqueWriteGuard()64 ~UniqueWriteGuard() 65 { 66 rwLockable_.UnLockWrite(); 67 } 68 69 private: 70 UniqueWriteGuard() = delete; 71 72 private: 73 RWLockable &rwLockable_; 74 }; 75 76 77 template <typename RWLockable> 78 class UniqueReadGuard : NoCopyable { 79 public: UniqueReadGuard(RWLockable & rwLockable)80 explicit UniqueReadGuard(RWLockable &rwLockable) 81 : rwLockable_(rwLockable) 82 { 83 rwLockable_.LockRead(); 84 } 85 ~UniqueReadGuard()86 ~UniqueReadGuard() 87 { 88 rwLockable_.UnLockRead(); 89 } 90 91 private: 92 UniqueReadGuard() = delete; 93 94 private: 95 RWLockable &rwLockable_; 96 }; 97 98 } // namespace Utils 99 } // namespace OHOS 100 #endif 101 102