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/////////////////////////////////////////////////////////////////////////// // // Copyright (c) 2005-2012, Industrial Light & Magic, a division of Lucas // Digital Ltd. LLC // // All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following disclaimer // in the documentation and/or other materials provided with the // distribution. // * Neither the name of Industrial Light & Magic nor the names of // its contributors may be used to endorse or promote products derived // from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. // /////////////////////////////////////////////////////////////////////////// #ifndef INCLUDED_ILM_THREAD_MUTEX_H #define INCLUDED_ILM_THREAD_MUTEX_H //----------------------------------------------------------------------------- // // class Mutex, class Lock // // Class Mutex is a wrapper for a system-dependent mutual exclusion // mechanism. Actual locking and unlocking of a Mutex object must // be performed using an instance of a Lock (defined below). // // Class lock provides safe locking and unlocking of mutexes even in // the presence of C++ exceptions. Constructing a Lock object locks // the mutex; destroying the Lock unlocks the mutex. // // Lock objects are not themselves thread-safe. You should never // share a Lock object among multiple threads. // // Typical usage: // // Mutex mtx; // Create a Mutex object that is visible // //to multiple threads // // ... // create some threads // // // Then, within each thread, construct a critical section like so: // // { // Lock lock (mtx); // Lock constructor locks the mutex // ... // do some computation on shared data // } // leaving the block unlocks the mutex // //----------------------------------------------------------------------------- #include "IlmThreadExport.h" #include "IlmBaseConfig.h" #include "IlmThreadNamespace.h" #if defined _WIN32 || defined _WIN64 #ifdef NOMINMAX #undef NOMINMAX #endif #define NOMINMAX #include <windows.h> #elif HAVE_PTHREAD #include <pthread.h> #endif ILMTHREAD_INTERNAL_NAMESPACE_HEADER_ENTER class Lock; class ILMTHREAD_EXPORT Mutex { public: Mutex (); virtual ~Mutex (); private: void lock () const; void unlock () const; #if defined _WIN32 || defined _WIN64 mutable CRITICAL_SECTION _mutex; #elif HAVE_PTHREAD mutable pthread_mutex_t _mutex; #endif void operator = (const Mutex& M); // not implemented Mutex (const Mutex& M); // not implemented friend class Lock; }; class ILMTHREAD_EXPORT Lock { public: Lock (const Mutex& m, bool autoLock = true): _mutex (m), _locked (false) { if (autoLock) { _mutex.lock(); _locked = true; } } ~Lock () { if (_locked) _mutex.unlock(); } void acquire () { _mutex.lock(); _locked = true; } void release () { _mutex.unlock(); _locked = false; } bool locked () { return _locked; } private: const Mutex & _mutex; bool _locked; }; ILMTHREAD_INTERNAL_NAMESPACE_HEADER_EXIT #endif // INCLUDED_ILM_THREAD_MUTEX_H