ScopedLock.h

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