86 lines
1.7 KiB
C
86 lines
1.7 KiB
C
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//====== Copyright <20> 1996-2005, Valve Corporation, All rights reserved. =======
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//
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// Purpose:
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//
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//=============================================================================
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#ifndef THREADSAFEREFCOUNTEDOBJECT_H
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#define THREADSAFEREFCOUNTEDOBJECT_H
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#ifdef _WIN32
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#pragma once
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#endif
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// This class can be used for fast access to an object from multiple threads,
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// and the main thread can wait until the threads are done using the object before it frees the object.
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template< class T >
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class CThreadSafeRefCountedObject
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{
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public:
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CThreadSafeRefCountedObject( T initVal )
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{
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m_RefCount = 0;
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m_pObject = initVal;
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m_RefCount = 0;
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}
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void Init( T pObj )
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{
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Assert( ThreadInMainThread() );
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Assert( !m_pObject );
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m_RefCount = 0;
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m_pObject = pObj;
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m_RefCount = 1;
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}
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// Threads that access the object need to use AddRef/Release to access it.
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T AddRef()
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{
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if ( ++m_RefCount > 1 )
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{
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return m_pObject;
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}
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else
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{
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// If the refcount was 0 when we called this, then the whitelist is about to be freed.
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--m_RefCount;
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return NULL;
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}
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}
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void ReleaseRef( T pObj )
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{
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if ( --m_RefCount >= 1 )
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{
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Assert( m_pObject == pObj );
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}
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}
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// The main thread can use this to access the object, since only it can Init() and Free() the object.
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T GetInMainThread()
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{
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Assert( ThreadInMainThread() );
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return m_pObject;
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}
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// The main thread calls this after it has released its last reference to the object.
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void ResetWhenNoRemainingReferences( T newValue )
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{
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Assert( ThreadInMainThread() );
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// Wait until we can free it.
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while ( m_RefCount > 0 )
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{
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CThread::Sleep( 20 );
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}
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m_pObject = newValue;
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}
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private:
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CInterlockedIntT<long> m_RefCount;
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T m_pObject;
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};
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#endif // THREADSAFEREFCOUNTEDOBJECT_H
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