// Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

//

#ifndef __MOUTPUTSTREAMOBSERVER_H__

#define __MOUTPUTSTREAMOBSERVER_H__

#include <e32std.h>

class MOutputStreamObserver

/**	

The MOutputStream and MOutputStreamObserver classes provide the API to send

data to a connected remote host. They encapsulate the outbound stream of a 

connected socket. 

The output socket observer must bind itself to the output stream before using

any of the other MOutputStream functions. The MOutputStream::Bind() API is 

used to do this binding. When done for the first time the output stream moves

from the Idle state to the PendingSend state.

Once an observer has been bound to the output stream data can be sent to the

connected host using the MOutputStream::SendDataReq() API. This can only be 

done when the output stream is in the PendingSend state otherwise a panic 

occurs. The MOutputStream::SendDataReq() API changes the output stream state

to the SentData state. 

The supplied data buffer must remain valid until the observer is notified 

that the send has been successful. This is done using the 

MOutputStreamObserver::SendDataCnf() API. The output stream moves back to 

the PendingSend state.

The output stream can only be re-bound to another observer when in the 

PendingSend state. The re-binding does not change the state of the output

stream.

There are two ways to shutdown the stream - asynchronously (standard use) and

synchronously. 

In normal use the asynchronous MOutputSocket::ShutdownReq() API can be used. 

The output stream changes to the Closing state. The observer is notified that

the stream has closed via the MOutputStreamObserver::OutputStreamCloseInd()

API. The output stream is then in the Closed state. It is no longer valid to

use the output stream and to do so will cause an access violation.

With the asynchronous shutdown the corresponding input stream is also shutdown.

Its observer is notified that the input stream has been closed. Similarly, 

if the corresponding input stream has been shutdown synchronously or 

asynchronously the output stream observer will be notified that the stream 

has been closed.

The MOutputSocket::Close() API closes the output stream synchronously. In 

this case the output stream observer will not be notified. Once the the call

completes the output stream is in the Closed state and is no longer valid. 

This synchronous close should be used when an asynchronous shutdown is not 

appropriate, e.g. when deleting the observer object in error conditions.

Similar to the asynchronous shutdown the corresponding input stream is also 

shutdown and its observer notified.

The MOutputStream::SecureClientReq() API allows the connection to be upgraded

to be secure. This request initiates a secure handshake - the local host of 

the connection is the client and the remote host is the server in the 

handshake. During the handshake, the corresponding input stream is suspended -

no data will be received.

If the secure handshake is successful the output stream observer is notified 

using the MOutputStreamObserver::SecureClientCnf() API. The input stream

resumes its activity. If the secure handshake was not successful then the 

stream handles the error in the normal manner.

The certificate information for the secure connection can be obtained using 

the MOutputStream::ServerCert() API.

@see		MOutputStream

*/

	{

public:	// methods

/**	

	Notifies the output stream observer that the data has been succeessfully

	sent to the remote host.

	@post		The output stream in the PendingSend state.

*/

	virtual void SendDataCnfL() =0;

/**

	Notifies the output stream observer that secure upgrade on the connection

	has completed successfully.

	@post		The output stream in the PendingSend state.

*/

	virtual void SecureClientCnf() =0;

/**

	Notifies the output stream observer that the socket connection with the

	remote host has been closed. The output stream is no longer valid.

	@param		aError	The error code explaining why the socket connection has

						closed. A value of KErrNone indicates that either the

						input or output stream observer requested that the 

						socket connection be closed.

	@post		The output stream is in the Closed state and is no longer valid.

*/

	virtual void OutputStreamCloseInd(TInt aError) =0;

	virtual void OnSendTimeOut() =0;

	virtual TInt SendTimeOutVal() =0;

private:	// methods

/**

	Reserved function for future expansion.

*/

	virtual void MOutputStreamObserver_Reserved() =0;

	};

#endif	// __MOUTPUTSTREAMOBSERVER_H__