--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/devsound/a3facf/inc/maudiostream.h Tue Feb 02 01:56:55 2010 +0200
@@ -0,0 +1,327 @@
+/*
+* Copyright (c) 2007-2009 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:
+*
+*/
+
+
+
+
+/**
+ @file
+ @publishedPartner
+ @released
+*/
+
+#ifndef MAUDIOSTREAM_H
+#define MAUDIOSTREAM_H
+
+#include <e32base.h>
+#include <f32file.h>
+#include <mmf/common/mmfcontroller.h>
+#include <a3f/a3fbase.h>
+
+class MAudioStreamObserver;
+class MAudioCodecObserver;
+class MAudioCodec;
+class MAudioProcessingUnit;
+
+/**
+ * this is the main control interface for the state of a processing unit chain.
+ *
+ * An AudioStream object binds together audio components processing the same data.
+ * An AudioStrem executes the audio processing states as requested by the client. The processing units
+ * attached to a stream will follow the state of the stream.
+ *
+ * The possible states of an AudioStream object are:
+ * EUninitialized: The state which the chain is in initially.
+ * The logical chain can be constructed.
+ * The settings in the logical chain cannot be related to the adaptation because no adaptation has been selected yet.
+ *
+ * EInitialized: this state is set after a successful initialization request.
+ * EIdle: All the chain resources are allocated, however, no processing time
+ * (other than expended to put the chain into EIdle state) is consumed in this phase.
+ * EPrimed: As per EIdle, but the stream can consume processing time, by filling its buffers.
+ * EActive: The chain has all the resources as per EIdle and EPrimed but also has started to
+ * process the actions requested by the client.
+ * EDead: The stream can no longer function due to fatal error.
+ * The logical chain still exists, but any physical resources should be reclaimed by the adaptation.
+ *
+ * The MAudioStreamObserver includes completion callbacks for many of the methods of MAudioStream.
+ * The protocol is such that when an asynchronous method is called and KErrNone is returned,
+ * then the call will be followed by a corresponding callback. if the returned error code from
+ * the asynchronous function is other than KErrNone, then a callback will not be made as
+ * a result of that method call. The callbacks will always occur out-of-context.
+ * Note that many of the functions will also require a context commit for the actual processing to take place.
+ */
+class MAudioStream
+ {
+public:
+ /**
+ * Registers an audio stream observer.
+ *
+ * Note that this function is meant for clients of the Audio Stream.
+ * The client should unregister using UnregisterAudioStreamObserver() when applicable.
+ *
+ * @param aObserver reference to the observer to register.
+ * @return an error code. KErrNone if successful.
+ * KErrAlreadyExists if the client is already registered.
+ * KErrOutOfMemory in case of memory exhaustion.
+ */
+ virtual TInt RegisterAudioStreamObserver(MAudioStreamObserver& aObserver)=0;
+
+ /**
+ * Unregisters an audio stream observer.
+ *
+ * @param aObserver reference to the observer to unregister.
+ * @return an error code. KErrNone if successful. KErrNotFound if the client has not been registered as observer.
+ */
+ virtual void UnregisterAudioStreamObserver(MAudioStreamObserver& aObserver)=0;
+
+
+ /**
+ * Sets the type of audio being processed in this context.
+ *
+ * The audio type settings are used by the resource control subsystem when it arbitrates between multiple clients
+ * trying to access the same resource. Additionally it may impact the availability of certain audio features for the client.
+ * It may also have an effect on other aspects, including, but not limited to routing and automatically applied effects.
+ * The audio types available for the client may be limited by the platform security capabilities, vendorId etc of the client application.
+ *
+ * @param aAudioTypeSettings defines the settings associated with this stream.
+ * @return an error code. KErrNone if successful, otherwise one of the system wide error codes.
+ */
+ virtual TInt SetAudioType(const TAudioTypeSettings& aAudioTypeSettings)=0;
+
+ /**
+ * Fetch the type of audio being processed in this stream.
+ *
+ * @param aAudioTypeSettings On return contains the audio type of this stream.
+ */
+ virtual void GetAudioType(TAudioTypeSettings& aAudioTypeSettings) const = 0;
+
+ /**
+ * Requests a transition to the EInitialized state.
+ *
+ * this function is asynchronous, and its successful return merely issues a request which is acted upon on Commit(),
+ * and while will lead to a StateEvent() callback. this function is only allowed while the stream is in EUninitialized state.
+ * A call in any other state will cause an error code of KErrNotReady to be returned.
+ *
+ * @return an error code. if KErrNone, the state transition has been requested,
+ * and there will be a StateEvent() callback following Commit().
+ * On error, there is no request made: KErrNotReady states the stream if not in valid current state,
+ * otherwise one of the system-wide error codes.
+ */
+ virtual TInt Initialize()=0;
+
+ /**
+ * Requests a transition to the EIdle state.
+ *
+ * this function is asynchronous, and its successful return merely issues a request which is acted upon on Commit(),
+ * and while will lead to a StateEvent() callback. this function is only allowed while the stream is in EInitialized state.
+ * A call in any other state will cause an error code of KErrNotReady to be returned
+ *
+ * The resources must be released using Unload() when they are no longer needed.
+ * Note that it is recommended that the resources are not kept reserved for long periods of inactivity,
+ * since it may prevent other audio streams from becoming active by stealing resources they need to use
+ *
+ * @return An error code. if KErrNone, the state transition has been requested,
+ * and there will be a StateEvent() callback following Commit().
+ * On error, there is no request made: KErrNotReady states the stream if not in valid current state,
+ * otherwise one of the system-wide error codes.
+ */
+ virtual TInt Load()=0;
+
+ /**
+ * Starts the audio processing. this function is only allowed while the stream is in EIdle or EPrimed states.
+ *
+ * The start-up procedures include requesting permission for audio processing from audio policy.
+ *
+ * @return an error code. A call in any state different to EIdle or EPrimed will cause an error code of KErrNotReady.
+ * if permission to start is denied by audio policy, a state change back to EPrimed will occur with error code KErrAccessDenied
+ */
+ virtual TInt Activate()=0;
+
+ /**
+ * Requests a transition to the Idle state – stopping the ongoing operation.
+ *
+ * this function is asynchronous, and its successful return merely issues a request which is acted upon on Commit(),
+ * and while will lead to a StateEvent() callback this function is only allowed while the stream is either Active or Primed.
+ * A call in any other state will cause an error code of KErrNotReady to be returned.
+ * @return An error code. if KErrNone, the state transition has been requested, and there will be a StateEvent() callback
+ * following Commit(). On error, there is no request made: KErrNotReady states the stream if not in valid current state,
+ * otherwise one of the system-wide error codes
+ */
+ virtual TInt Stop()=0;
+
+ /**
+ * Prepares the audio stream for releasing the resources reserved for it and for the processing units attached to the stream.
+ *
+ * this function is only allowed while the stream is EIdle state.
+ * A call in any other state will cause an error code of KErrNotReady to be returned.
+ *
+ * During this call the stream will query all attached processing units whether they are ready to unload.
+ * if a processing unit indicates that it is not ready to uninitialize, then an error code other than KErrNone will be returned.
+ * Provided that this call succeeds, the actual unloading process will begins once Commit() is called for the context of this stream.
+ *
+ * @return An error code. KErrNone if successful.
+ * KErrNotReady if called while the stream is not in correct state.
+ * Other system wide error codes are also possible.
+ */
+ virtual TInt Unload()=0;
+
+ /**
+ * Requests a transition to the Unitialized state – returning the stream to its initial state.
+ *
+ * this function is asynchronous, and its successful return merely issues a request which is acted upon on Commit(),
+ * and while will lead to a StateEvent() callback. this function is only allowed while the stream is in Initialized state.
+ * A call in any other state will cause an error code of KErrNotReady to be returned.
+ *
+ * @return an error code. if KErrNone, the state transition has been requested, and there will be a StateEvent() callback
+ * following Commit(). On error, there is no request made: KErrNotReady states the stream if not in valid current state,
+ * otherwise one of the system-wide error codes.
+ */
+ virtual TInt Uninitialize()=0;
+
+ /**
+ * Requests a transition to the EPrime state.
+ *
+ * this function is asynchronous, and its successful return merely issues a request which is acted upon on Commit(),
+ * and while will lead to a StateEvent() callback. this function is only allowed while the stream is in EActive
+ * (semantics of Prime in EActive– go into a buffering pause) or EIdle state (semantics of Prime in EIdle – start to buffer).
+ * A call in any other state will cause an error code of KErrNotReady to be returned. Not all streams support Prime.
+ *
+ * @return an error code. if KErrNone, the state transition has been requested, and there will be a StateEvent() callback
+ * following Commit(). On error, there is no request made: KErrNotReady states the stream if not in valid current state,
+ * otherwise one of the system-wide error codes
+ */
+ virtual TInt Prime()=0;
+
+
+ /**
+ * Empty any buffers that have been filled.
+ *
+ * Reclain any outstanding buffers from the client, if required.
+ * this function is only allowed while the stream is in Idle state. this is an asynchronous operation.
+ * if the call returns KErrNone it merely indicates a flush has been requested and there will be a subsequent FlushComplete() callback.
+ * Note that this does not relate to the Commit() cycle, and is not considered transactional.
+ *
+ * @return a system wide error code. KErrNone if successful.
+ * KErrNotReady if called while the stream is not in correct state. Other system wide error codes are also possible.
+ */
+ virtual TInt Flush()=0;
+
+ /**
+ * Adds an audio source to this stream.
+ *
+ * A stream cannot operate before a source has been set.
+ * The source must be removed from the stream before the sink or the stream is destroyed.
+ * The source can only be set while the stream is in uninitialized state.
+ * this is an asynchronous call and the completion will be indicated to the
+ * client via a callback in the stream observer interface.
+ *
+ * @param aSource the audio source for this stream.
+ * @return an error code. KErrNone if successful, there will be a subsequent callback on MAudioStreamObserver::AddProcessingUnitComplete().
+ * KErrInUse a source has already been set fot this stream.
+ * KErrNotReady the stream is not in correct state.
+ */
+ virtual TInt AddSource(MAudioProcessingUnit* aSource)=0;
+
+ /**
+ * Adds sink for this stream.
+ *
+ * Stream cannot operate before source and sink have been set.
+ * The sink must be removed from the stream before it is destroyed.
+ * The sink can only be set while the stream is in uninitialized state.
+ * this is an asynchronous call and the completion will be indicated to the
+ * client via a callback in the stream observer interface.
+ *
+ * @param aSink the sink for this stream
+ * @return an error code. KErrNone if successful, there will be a subsequent callback on MAudioStreamObserver::AddProcessingUnitComplete().
+ * KErrInUse a sink has already been set fot this stream.
+ * KErrNotReady the stream is not in correct state,
+ */
+ virtual TInt AddSink(MAudioProcessingUnit* aSink)=0;
+
+ /**
+ * Adds an codec for this stream.
+ *
+ * The codec must be removed from the stream before the codec or the stream
+ * is deleted. The codec can only be set while the stream is in uninitialized state.
+ * this is an asynchronous call and the completion will be indicated to
+ * the client via a callback in the stream observer interface.
+ *
+ * @param aCodec the codec for this stream
+ * @return an error code. KErrNone if successful, there will be a subsequent callback on MAudioStreamObserver::AddProcessingUnitComplete().
+ * KErrInUse a codec has already been set fot this stream.
+ * KErrNotReady the stream is not in correct state.
+ */
+ virtual TInt AddAudioCodec(MAudioProcessingUnit* aCodec)=0;
+
+ /**
+ * Adds an audio processing unit to this stream.
+ *
+ * The processing unit must be removed from the stream before the processing unit or the stream is removed from the context.
+ * The supplied component must implement the AudioGainControl feature.
+ *
+ * @param aGainControl the gain control to add to this stream.
+ * @return KErrNone if succesful returned, there will be a subsequent callback on MAudioStreamObserver::AddProcessingUnitComplete().
+ * KErrInUse a gain control has already been set fot this stream.
+ * KErrNotReady the stream is not in correct state.
+ */
+ virtual TInt AddGainControl(MAudioProcessingUnit* aGainControl)=0;
+
+ /**
+ * Removes any audio processing unit from this stream, whether it has been added by AddSource(), AddSink(), AddCodec() or AddGainControl().
+ * this is an asynchronous function, on successful call there will be a subsequent RemoveProcessingUnitComplete() callback.
+ * @param aProcessingUnit the processing unit to remove.
+ * @return a system wide error code, KErrNone if successful, or the processing unit had not been added to the stream.
+ * KErrNotReady the decoder is not in correct state. Other system wide error codes are also possible.
+ */
+ virtual TInt RemoveProcessingUnit(MAudioProcessingUnit* aProcessingUnit)=0;
+
+ /**
+ * Resets the duration counter.
+ *
+ * Used to differentiate between when a stream has been momentarily interrupted and when
+ * a different conceptual use-case is underway. Defined for EIdle.
+ */
+ virtual TInt ResetStreamTime()=0;
+
+ /**
+ * Returns the duration of audio that has been processed from the hardware device perspective.
+ * The time is reset when the MAudioStream object transfers from Initialized state to Idle.
+ * as a result of calling Load(). It can be reset at other times using ResetStreamTime().
+ */
+ virtual TInt GetStreamTime(TTimeIntervalMicroSeconds& aStreamTime)=0;
+
+ /**
+ * A mechanism to obtain additional control APIs on the stream.
+ *
+ * These can be used to extend the basic play/record, pause, stop with future use-cases such as seek play.
+ *
+ * @param aType Uid that denotes the type of the interface.
+ * @return the pointer to the specified interface, or NULL if it does not exist. Must be cast to correct type by the user..
+ */
+ virtual TAny* Interface(TUid aType)=0;
+
+ /**
+ * Returns the component instance id.
+ *
+ * @return component instance id.
+ */
+ virtual TAudioStreamId InstanceId() const =0;
+
+ };
+
+#endif // MAUDIOSTREAM_H