69 lines
1.6 KiB
C++
69 lines
1.6 KiB
C++
/*
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* \brief Mutex primitive
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* \author Alexander Boettcher
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* \date 2020-01-24
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*
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* A 'Mutex' is a locking primitive designated for the mutual exclusion of
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* multiple threads executing a critical section, which is typically code that
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* mutates a shared variable.
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*
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* At initialization time, a mutex is in unlocked state. To enter and leave a
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* critical section, the methods 'acquire()' and 'release()' are provided.
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*
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* A mutex must not be used recursively. The subsequential attempt of aquiring
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* a mutex twice by the same thread ultimately results in a deadlock. This
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* misbehavior generates a warning message at runtime.
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*
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* Only the thread that aquired the mutex is permitted to release the mutex.
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* The violation of this invariant generates a warning message and leaves the
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* mutex unchanged.
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*
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* A 'Mutex::Guard' is provided, which acquires a mutex at construction time
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* and releases it automatically at the destruction time of the guard.
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*/
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/*
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* Copyright (C) 2020 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__BASE__MUTEX_H_
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#define _INCLUDE__BASE__MUTEX_H_
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#include <base/lock.h>
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#include <util/noncopyable.h>
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namespace Genode { class Mutex; }
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class Genode::Mutex : Noncopyable
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{
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private:
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Lock _lock { };
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public:
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Mutex() { }
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void acquire();
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void release();
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class Guard
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{
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private:
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Mutex &_mutex;
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public:
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explicit Guard(Mutex &mutex) : _mutex(mutex) { _mutex.acquire(); }
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~Guard() { _mutex.release(); }
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};
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};
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#endif /* _INCLUDE__BASE__MUTEX_H_ */
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