poco/Foundation/include/Poco/PipeStream.h

//
// PipeStream.h
//
// $Id: //poco/svn/Foundation/include/Poco/PipeStream.h#2 $
//
// Library: Foundation
// Package: Processes
// Module:  PipeStream
//
// Definition of the PipeStream class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef Foundation_PipeStream_INCLUDED
#define Foundation_PipeStream_INCLUDED


#include "Poco/Foundation.h"
#include "Poco/Pipe.h"
#include "Poco/BufferedStreamBuf.h"
#include <istream>
#include <ostream>


namespace Poco {


class Foundation_API PipeStreamBuf: public BufferedStreamBuf
	/// This is the streambuf class used for reading from and writing to a Pipe.
{
public:
	typedef BufferedStreamBuf::openmode openmode;
	
	PipeStreamBuf(const Pipe& pipe, openmode mode);
		/// Creates a PipeStreamBuf with the given Pipe.

	~PipeStreamBuf();
		/// Destroys the PipeStreamBuf.
		
	void close();
		/// Closes the pipe.
		
protected:
	int readFromDevice(char* buffer, std::streamsize length);
	int writeToDevice(const char* buffer, std::streamsize length);

private:
	enum 
	{
		STREAM_BUFFER_SIZE = 1024
	};

	Pipe _pipe;
};


class Foundation_API PipeIOS: public virtual std::ios
	/// The base class for PipeInputStream and
	/// PipeOutputStream.
	///
	/// This class is needed to ensure the correct initialization
	/// order of the stream buffer and base classes.
{
public:
	PipeIOS(const Pipe& pipe, openmode mode);
		/// Creates the PipeIOS with the given Pipe.
		
	~PipeIOS();
		/// Destroys the PipeIOS.
		///
		/// Flushes the buffer, but does not close the pipe.
		
	PipeStreamBuf* rdbuf();
		/// Returns a pointer to the internal PipeStreamBuf.
		
	void close();
		/// Flushes the stream and closes the pipe.

protected:
	PipeStreamBuf _buf;
};


class Foundation_API PipeOutputStream: public PipeIOS, public std::ostream
	/// An output stream for writing to a Pipe.
{
public:
	PipeOutputStream(const Pipe& pipe);
		/// Creates the PipeOutputStream with the given Pipe.

	~PipeOutputStream();
		/// Destroys the PipeOutputStream.
		///
		/// Flushes the buffer, but does not close the pipe.
};


class Foundation_API PipeInputStream: public PipeIOS, public std::istream
	/// An input stream for reading from a Pipe.
	///
	/// Using formatted input from a PipeInputStream
	/// is not recommended, due to the read-ahead behavior of
	/// istream with formatted reads.
{
public:
	PipeInputStream(const Pipe& pipe);
		/// Creates the PipeInputStream with the given Pipe.

	~PipeInputStream();
		/// Destroys the PipeInputStream.
};


} // namespace Poco


#endif // Foundation_PipeStream_INCLUDED