1/////////////////////////////////////////////////////////////////////////// 2// 3// Copyright (c) 2005, Industrial Light & Magic, a division of Lucas 4// Digital Ltd. LLC 5// 6// All rights reserved. 7// 8// Redistribution and use in source and binary forms, with or without 9// modification, are permitted provided that the following conditions are 10// met: 11// * Redistributions of source code must retain the above copyright 12// notice, this list of conditions and the following disclaimer. 13// * Redistributions in binary form must reproduce the above 14// copyright notice, this list of conditions and the following disclaimer 15// in the documentation and/or other materials provided with the 16// distribution. 17// * Neither the name of Industrial Light & Magic nor the names of 18// its contributors may be used to endorse or promote products derived 19// from this software without specific prior written permission. 20// 21// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 24// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 25// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 27// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 31// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32// 33/////////////////////////////////////////////////////////////////////////// 34 35#ifndef INCLUDED_ILM_THREAD_MUTEX_H 36#define INCLUDED_ILM_THREAD_MUTEX_H 37 38//----------------------------------------------------------------------------- 39// 40// class Mutex, class Lock 41// 42// Class Mutex is a wrapper for a system-dependent mutual exclusion 43// mechanism. Actual locking and unlocking of a Mutex object must 44// be performed using an instance of a Lock (defined below). 45// 46// Class lock provides safe locking and unlocking of mutexes even in 47// the presence of C++ exceptions. Constructing a Lock object locks 48// the mutex; destroying the Lock unlocks the mutex. 49// 50// Lock objects are not themselves thread-safe. You should never 51// share a Lock object among multiple threads. 52// 53// Typical usage: 54// 55// Mutex mtx; // Create a Mutex object that is visible 56// //to multiple threads 57// 58// ... // create some threads 59// 60// // Then, within each thread, construct a critical section like so: 61// 62// { 63// Lock lock (mtx); // Lock constructor locks the mutex 64// ... // do some computation on shared data 65// } // leaving the block unlocks the mutex 66// 67//----------------------------------------------------------------------------- 68 69#include "IlmBaseConfig.h" 70 71#if defined _WIN32 || defined _WIN64 72 #ifdef NOMINMAX 73 #undef NOMINMAX 74 #endif 75 #define NOMINMAX 76 #include <windows.h> 77#elif HAVE_PTHREAD 78 #include <pthread.h> 79#endif 80 81namespace IlmThread { 82 83class Lock; 84 85 86class Mutex 87{ 88 public: 89 90 Mutex (); 91 virtual ~Mutex (); 92 93 private: 94 95 void lock () const; 96 void unlock () const; 97 98 #if defined _WIN32 || defined _WIN64 99 mutable CRITICAL_SECTION _mutex; 100 #elif HAVE_PTHREAD 101 mutable pthread_mutex_t _mutex; 102 #endif 103 104 void operator = (const Mutex& M); // not implemented 105 Mutex (const Mutex& M); // not implemented 106 107 friend class Lock; 108}; 109 110 111class Lock 112{ 113 public: 114 115 Lock (const Mutex& m, bool autoLock = true): 116 _mutex (m), 117 _locked (false) 118 { 119 if (autoLock) 120 { 121 _mutex.lock(); 122 _locked = true; 123 } 124 } 125 126 ~Lock () 127 { 128 if (_locked) 129 _mutex.unlock(); 130 } 131 132 void acquire () 133 { 134 _mutex.lock(); 135 _locked = true; 136 } 137 138 void release () 139 { 140 _mutex.unlock(); 141 _locked = false; 142 } 143 144 bool locked () 145 { 146 return _locked; 147 } 148 149 private: 150 151 const Mutex & _mutex; 152 bool _locked; 153}; 154 155 156} // namespace IlmThread 157 158#endif 159