154 lines
5.1 KiB
C++
154 lines
5.1 KiB
C++
///////////////////////////////////////////////////////////////////////////
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//
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// Copyright (c) 2005-2012, Industrial Light & Magic, a division of Lucas
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// Digital Ltd. LLC
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Industrial Light & Magic nor the names of
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// its contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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///////////////////////////////////////////////////////////////////////////
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#ifndef INCLUDED_ILM_THREAD_H
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#define INCLUDED_ILM_THREAD_H
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//-----------------------------------------------------------------------------
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//
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// class Thread
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//
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// Class Thread is a portable interface to a system-dependent thread
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// primitive. In order to make a thread actually do something useful,
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// you must derive a subclass from class Thread and implement the
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// run() function. If the operating system supports threading then
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// the run() function will be executed int a new thread.
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//
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// The actual creation of the thread is done by the start() routine
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// which then calls the run() function. In general the start()
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// routine should be called from the constructor of the derived class.
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//
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// The base-class thread destructor will join/destroy the thread.
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//
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// IMPORTANT: Due to the mechanisms that encapsulate the low-level
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// threading primitives in a C++ class there is a race condition
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// with code resembling the following:
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//
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// {
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// WorkerThread myThread;
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// } // myThread goes out of scope, is destroyed
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// // and the thread is joined
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//
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// The race is between the parent thread joining the child thread
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// in the destructor of myThread, and the run() function in the
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// child thread. If the destructor gets executed first then run()
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// will be called with an invalid "this" pointer.
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//
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// This issue can be fixed by using a Semaphore to keep track of
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// whether the run() function has already been called. You can
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// include a Semaphore member variable within your derived class
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// which you post() on in the run() function, and wait() on in the
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// destructor before the thread is joined. Alternatively you could
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// do something like this:
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//
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// Semaphore runStarted;
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//
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// void WorkerThread::run ()
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// {
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// runStarted.post()
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// // do some work
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// ...
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// }
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//
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// {
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// WorkerThread myThread;
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// runStarted.wait (); // ensure that we have started
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// // the run function
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// } // myThread goes out of scope, is destroyed
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// // and the thread is joined
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//
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//-----------------------------------------------------------------------------
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#include "IlmBaseConfig.h"
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#include "IlmThreadExport.h"
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#include "IlmThreadNamespace.h"
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#ifdef ILMBASE_FORCE_CXX03
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# if defined _WIN32 || defined _WIN64
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# ifdef NOMINMAX
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# undef NOMINMAX
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# endif
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# define NOMINMAX
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# include <windows.h>
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# include <process.h>
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# elif HAVE_PTHREAD
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# include <pthread.h>
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# endif
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#else
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# include <thread>
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#endif
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ILMTHREAD_INTERNAL_NAMESPACE_HEADER_ENTER
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//
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// Query function to determine if the current platform supports
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// threads AND this library was compiled with threading enabled.
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//
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ILMTHREAD_EXPORT bool supportsThreads ();
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class Thread
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{
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public:
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ILMTHREAD_EXPORT Thread ();
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ILMTHREAD_EXPORT virtual ~Thread ();
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ILMTHREAD_EXPORT void start ();
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ILMTHREAD_EXPORT virtual void run () = 0;
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private:
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#ifdef ILMBASE_FORCE_CXX03
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# if defined _WIN32 || defined _WIN64
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HANDLE _thread;
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# elif HAVE_PTHREAD
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pthread_t _thread;
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# endif
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void operator = (const Thread& t); // not implemented
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Thread (const Thread& t); // not implemented
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#else
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std::thread _thread;
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Thread &operator= (const Thread& t) = delete;
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Thread (const Thread& t) = delete;
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#endif
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};
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ILMTHREAD_INTERNAL_NAMESPACE_HEADER_EXIT
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#endif // INCLUDED_ILM_THREAD_H
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