ClickHouse/base/poco/Foundation/include/Poco/PipeStream.h

//
// PipeStream.h
//
// Library: Foundation
// Package: Processes
// Module:  PipeStream
//
// Definition of the PipeStream class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#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