historical/toontown-classic.git/panda/include/cycleDataLockedReader.h

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