77 lines
2.7 KiB
C++
77 lines
2.7 KiB
C++
/**
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* PANDA 3D SOFTWARE
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* Copyright (c) Carnegie Mellon University. All rights reserved.
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*
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* All use of this software is subject to the terms of the revised BSD
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* license. You should have received a copy of this license along
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* with this source code in a file named "LICENSE."
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*
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* @file cycleDataLockedReader.h
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* @author drose
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* @date 2006-04-30
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*/
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#ifndef CYCLEDATALOCKEDREADER_H
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#define CYCLEDATALOCKEDREADER_H
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#include "pandabase.h"
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#include "cycleData.h"
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#include "pipelineCycler.h"
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#include "thread.h"
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/**
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* This template class calls PipelineCycler::read() in the constructor and
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* PipelineCycler::release_read() in the destructor. In the interim, it
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* provides a transparent read-only access to the CycleData.
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*
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* Since a lock is held on the data while the instance of this class exists,
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* no other thread may modify any stage of the pipeline during that time.
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* Thus, this class is appropriate to use for cases in which you might want to
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* read and then modify the data. It is possible to pass an instance of
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* CycleDataLockedReader to the CycleDataWriter constructor, which
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* automatically elevates the read lock into a write lock.
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*
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* It exists as a syntactic convenience to access the data in the CycleData.
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* It also allows the whole system to compile down to nothing if DO_PIPELINING
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* is not defined.
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*/
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template<class CycleDataType>
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class CycleDataLockedReader {
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public:
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// By hiding this template from interrogate, we improve compile-time speed
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// and memory utilization.
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#ifndef CPPPARSER
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INLINE CycleDataLockedReader(const PipelineCycler<CycleDataType> &cycler,
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Thread *current_thread = Thread::get_current_thread());
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INLINE CycleDataLockedReader(const CycleDataLockedReader<CycleDataType> ©);
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INLINE CycleDataLockedReader(CycleDataLockedReader<CycleDataType> &&from) noexcept;
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INLINE void operator = (const CycleDataLockedReader<CycleDataType> ©);
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INLINE void operator = (CycleDataLockedReader<CycleDataType> &&from) noexcept;
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INLINE ~CycleDataLockedReader();
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INLINE const CycleDataType *operator -> () const;
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INLINE operator const CycleDataType * () const;
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INLINE const CycleDataType *take_pointer();
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INLINE Thread *get_current_thread() const;
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private:
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#ifdef DO_PIPELINING
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// This is the data stored for a real pipelining implementation.
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const PipelineCycler<CycleDataType> *_cycler;
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Thread *_current_thread;
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const CycleDataType *_pointer;
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CycleDataType *_write_pointer;
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#else // !DO_PIPELINING
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// This is all we need for the trivial, do-nothing implementation.
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const CycleDataType *_pointer;
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#endif // DO_PIPELINING
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#endif // CPPPARSER
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};
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#include "cycleDataLockedReader.I"
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#endif
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