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// Copyright (c) 2012-2017 VideoStitch SAS
// Copyright (c) 2018 stitchEm
#pragma once
#include "libvideostitch/utils/semaphore.hpp"
namespace VideoStitch {
/**
* Read/Write mutex.
*/
class RWMutex {
public:
virtual ~RWMutex();
virtual void writerLock() = 0;
virtual void writerUnlock() = 0;
virtual void readerLock() = 0;
virtual void readerUnlock() = 0;
};
/**
* Read RAII on Read/Write mutex.
*/
class ScopedReaderLock {
public:
explicit ScopedReaderLock(RWMutex& rwMutex) : rwMutex(rwMutex) { rwMutex.readerLock(); }
~ScopedReaderLock() { rwMutex.readerUnlock(); }
private:
RWMutex& rwMutex;
};
/**
* Write RAII on Read/Write mutex.
*/
class ScopedWriterLock {
public:
explicit ScopedWriterLock(RWMutex& rwMutex) : rwMutex(rwMutex) { rwMutex.writerLock(); }
~ScopedWriterLock() { rwMutex.writerUnlock(); }
private:
RWMutex& rwMutex;
};
/**
* A RW mutex that gives readers the priority. Will starve the writer.
*/
class ReaderPriorityMutex : public RWMutex {
public:
ReaderPriorityMutex();
void writerLock();
void writerUnlock();
void readerLock();
void readerUnlock();
private:
Semaphore writerSem;
Semaphore readerSem;
int pendingReads;
};
} // namespace VideoStitch