sl@0: /*
sl@0: * Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: * All rights reserved.
sl@0: * This component and the accompanying materials are made available
sl@0: * under the terms of "Eclipse Public License v1.0"
sl@0: * which accompanies this distribution, and is available
sl@0: * at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: *
sl@0: * Initial Contributors:
sl@0: * Nokia Corporation - initial contribution.
sl@0: *
sl@0: * Contributors:
sl@0: *
sl@0: * Description:
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: 
sl@0: 
sl@0: /**
sl@0:  @file
sl@0:  @publishedPartner 
sl@0:  @released
sl@0: */
sl@0: 
sl@0: 
sl@0: #ifndef MAUDIOSTREAMOBSERVER_H
sl@0: #define MAUDIOSTREAMOBSERVER_H
sl@0: 
sl@0: #include <e32base.h>
sl@0: #include <a3f/a3fbase.h>
sl@0: #include <a3f/maudiostream.h>
sl@0: 
sl@0: /**
sl@0:  * An interface to a set of AudioStream callback functions.
sl@0:  *
sl@0:  * this serves as the method of communication between the client and the
sl@0:  * AudioStream.
sl@0:  *
sl@0:  * The class is a mixin and is intended to be inherited by the client class
sl@0:  * that is interested in observing the AudioStream operation. The functions
sl@0:  * encapsulated by this class are called when specific events occur while
sl@0:  * processing audio.
sl@0:  */
sl@0: class MAudioStreamObserver
sl@0: 	{
sl@0: public:
sl@0: 	/**
sl@0: 	 * Handles audio stream state change event.
sl@0: 	 *
sl@0: 	 * @param aStream A reference to the stream whose state changed.
sl@0: 	 * @param aReason A set of values describing why the state change occurred 
sl@0: 	 * corresponding to the system-wide error codes. The value will be KErrNone on successful calls.
sl@0: 	 * @param aNewState indicating the state in which the audio stream has changed.
sl@0: 	 */
sl@0: 	virtual void StateEvent(MAudioStream& aStream , TInt aReason, TAudioState aNewState)=0;
sl@0: 
sl@0: 	/**
sl@0: 	 * Notifies that adding of processing unit to the stream has been completed successfully or otherwise.
sl@0: 	 *
sl@0: 	 * if the processing unit is added succesfully, then it must be removed from the
sl@0: 	 * stream before the processing unit is removed from the context or before the stream is removed.
sl@0: 	 *
sl@0: 	 * @param aStream A reference to the stream to which the processing unit was added.
sl@0: 	 * @param aInstance a pointer to the processing unit instance.
sl@0: 	 * @param aError an error code. KErrNone on success. Otherwise one of the system wide error codes.
sl@0: 	 */
sl@0: 	virtual void AddProcessingUnitComplete(MAudioStream& aStream, MAudioProcessingUnit* aInstance, TInt aError)=0;
sl@0: 
sl@0: 	/**
sl@0: 	 * Notifies that removing of processing unit from the stream has been completed
sl@0: 	 * successfully or otherwise.
sl@0: 	 * 
sl@0: 	 * if the processing unit has been added succesfully, then it must be removed
sl@0: 	 * from the stream, before the processing unit is removed from the
sl@0: 	 * context or before the stream is removed.
sl@0: 	 * 
sl@0: 	 * @param aStream A reference to the stream from which the processing unit has been removed.
sl@0: 	 * @param aType the processing unit type.
sl@0: 	 * @param aInstance a pointer to the processing unit instance.
sl@0: 	 * @param aError an error code. KErrNone on success. Otherwise one of the system wide error codes.
sl@0: 	 */
sl@0: 	virtual void RemoveProcessingUnitComplete(MAudioStream& aStream, MAudioProcessingUnit* aInstance, TInt aError)=0;
sl@0: 
sl@0: 	/**
sl@0: 	 * Call-back indicating that is the last buffer has been processed by the sink.
sl@0: 	 *
sl@0: 	 * @param aStream A reference to the stream.
sl@0: 	 */
sl@0: 	virtual void ProcessingFinished (MAudioStream& aStream)=0;
sl@0: 
sl@0: 	/**
sl@0: 	 * Signals completion of a Flush() operation.
sl@0: 	 *
sl@0: 	 * @param aStream A reference to the stream on which Flush() was called.  
sl@0: 	 * @param aError an error code. KErrAbort if the associated stream has been unloaded, and the buffers cease to exist.
sl@0: 	 */
sl@0: 	virtual void FlushComplete (MAudioStream& aStream, TInt aError) = 0;
sl@0: 
sl@0: 	};
sl@0: 
sl@0: #endif // MAUDIOSTREAMOBSERVER_H