#pragma once

#include "Object.h"
#include "Lock.h"
#include "Semaphore.h"

//An implementation of a readers-writers algorithm.
//Usage: Declare the ReadWrite, then lock by instantiating Reader or Writer.
class ReadWrite : NoCopy {
public:
	ReadWrite();
	~ReadWrite();

	//Lock as reader
	class Reader : NoCopy {
	public:
		Reader(const ReadWrite &rw);
		~Reader();
	private:
		const ReadWrite &rw;
	};

	//Lock as writer
	class Writer : NoCopy {
	public:
		//Could be const ReadWrite &rw, but if you need the const version
		//you are probably mis-using this object...
		Writer(ReadWrite &rw);
		~Writer();
	private:
		ReadWrite &rw;
	};
private:
	mutable nat readers;
	mutable util::Lock readersLock;
	mutable Semaphore writers;
};

//Simplification of locking as reader and writer.
typedef ReadWrite::Reader Reader;
typedef ReadWrite::Writer Writer;