82 lines
3.0 KiB
C++
82 lines
3.0 KiB
C++
// Filename: cycleDataLockedReader.h
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// Created by: drose (30Apr06)
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//
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////////////////////////////////////////////////////////////////////
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//
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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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////////////////////////////////////////////////////////////////////
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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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// Class : CycleDataLockedReader
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// Description : This template class calls PipelineCycler::read() in
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// the constructor and PipelineCycler::release_read() in
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// the destructor. In the interim, it provides a
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// 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
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// of this class exists, no other thread may modify any
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// stage of the pipeline during that time. Thus, this
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// class is appropriate to use for cases in which you
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// might want to read and then modify the data. It is
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// possible to pass an instance of CycleDataLockedReader
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// to the CycleDataWriter constructor, which
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// automatically elevates the read lock into a write
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// lock.
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//
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// It exists as a syntactic convenience to access the
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// data in the CycleData. It also allows the whole
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// system to compile down to nothing if
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// DO_PIPELINING 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
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// speed 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 void operator = (const CycleDataLockedReader<CycleDataType> ©);
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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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