ScopedLock.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2018 ARM Limited
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 #ifndef MBED_SCOPEDLOCK_H
00018 #define MBED_SCOPEDLOCK_H
00019 
00020 #include "platform/NonCopyable.h"
00021 
00022 namespace mbed {
00023 
00024 /** \addtogroup platform */
00025 /** @{*/
00026 /**
00027  * \defgroup platform_ScopedLock ScopedLock functions
00028  * @{
00029  */
00030 
00031 /** RAII-style mechanism for owning a lock of Lockable object for the duration of a scoped block
00032  *
00033  * @tparam Lockable The type implementing BasicLockable concept
00034  *
00035  * @note For type Lockable to be BasicLockable, the following conditions have to be satisfied:
00036  *        - has public member function @a lock which blocks until a lock can be obtained for the current execution context
00037  *        - has public member function @a unlock which releases the lock
00038  *
00039  * Usage:
00040  *
00041  * Example with rtos::Mutex
00042  *
00043  * @code
00044  * void foo(Mutex &m) {
00045  *     ScopedLock<Mutex> lock(m);
00046  *     // Mutex lock protects code in this block
00047  * }
00048  * @endcode
00049  *
00050  *
00051  * More generic example
00052  *
00053  * @code
00054  * template<typename Lockable>
00055  * void foo(Lockable& lockable) {
00056  *     ScopedLock<Lockable> lock(lockable);
00057  *     // Code in this block runs under lock
00058  * }
00059  * @endcode
00060  */
00061 template <typename Lockable>
00062 class ScopedLock : private NonCopyable<ScopedLock<Lockable> > {
00063 public:
00064     /** Locks given lockable object
00065      *
00066      * @param lockable reference to the instance of Lockable object
00067      * @note lockable object should outlive the ScopedLock object
00068      */
00069     ScopedLock(Lockable &lockable): _lockable(lockable)
00070     {
00071         _lockable.lock();
00072     }
00073 
00074     ~ScopedLock()
00075     {
00076         _lockable.unlock();
00077     }
00078 private:
00079     Lockable &_lockable;
00080 };
00081 
00082 /**@}*/
00083 
00084 /**@}*/
00085 
00086 } // embed
00087 
00088 #endif // MBED_SCOPEDLOCK_H