--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/devsound/a3facf/inc/maudiocontext.h Tue Feb 02 01:56:55 2010 +0200
@@ -0,0 +1,163 @@
+/*
+* Copyright (c) 2006-2009 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 MAUDIOCONTEXT_H
+#define MAUDIOCONTEXT_H
+
+#include <e32base.h>
+
+#include <a3f/a3fbase.h>
+
+class MAudioStream;
+class MAudioProcessingUnit;
+class MAudioContextObserver;
+
+/**
+ * An interface to an audio context.
+ *
+ * Audio context is a container for a set of logically related audio streams and audio processing units.
+ * All streams and processing units are created into a context.
+ * A new context can be created using an instance of CAudioContextFactory.
+ * When the context is no longer needed, it must be removed using CAudioContextFactory::DeleteAudioContext().
+ */
+class MAudioContext
+ {
+public:
+
+ /**
+ * Returns the context identifier.
+ *
+ * @return return the context identifier
+ */
+ virtual TAudioContextId ContextId() const = 0;
+
+ /**
+ * Creates a new audio stream into this context.
+ *
+ * The stream must be removed using DeleteAudioStream() when it is no longer needed.
+ *
+ * @param aStream on return contains a pointer to the created stream.
+ * @return an error code. KErrNone if successful, otherwise one of the system wide error codes.
+ */
+ virtual TInt CreateAudioStream(MAudioStream*& aStream)=0;
+
+ /**
+ * Deletes an audio stream from this context.
+ *
+ * After removing the stream all references to it will become invalid and must not be used.
+ * At the end of the call, aStream will have been set to NULL.
+ * Calling DeleteAudioStream() with a parameter whose value is NULL is itself a null operation.
+ * @param aStream a pointer to the stream to Delete.
+ * @return an error code. KErrNone if successful, otherwise one of the system wide error codes.
+ */
+ virtual void DeleteAudioStream(MAudioStream*& aStream)=0;
+
+ /**
+ * Creates a new audio processing unit into this context.
+ *
+ * The processing unit must be removed using DeleteProcessingUnit() when it is no longer needed.
+ *
+ * @param aType the type of the processing unit.
+ * @param aProcessingUnit on return contains a pointer to the created processing unit.
+ * @return an error code. KErrNone if successful, otherwise one of the system wide error codes.
+ */
+ virtual TInt CreateAudioProcessingUnit(TUid aTypeId, MAudioProcessingUnit*& aProcessingUnit)=0;
+
+ /**
+ * Deletes the audio processing unit from this context.
+ *
+ * After removing the processing unit all references to it will become invalid and must not be used.
+ * At the end of the call, aProcessingUnit will have been set to NULL.
+ * Calling DeleteAudioProcessingUnit() with a parameter whose value is NULL is itself a null operation.
+ * @param aProcessingUnit a pointer to the processing unit to remove.
+ * @return an error code. KErrNone if successful, otherwise one of the system wide error codes.
+ */
+ virtual void DeleteAudioProcessingUnit(MAudioProcessingUnit*& aProcessingUnit)=0;
+
+ /**
+ * Apply changes made to audio components associated with this context.
+ *
+ * A state change applied to an Audio Stream should be considered "pending" until Commit() is called,
+ * in that the adaptation merely records that the state setting has been requested and does not seek
+ * to implement the state change until Commit().
+ *
+ * Commit() can be thought of as an asynchronous call, and completion is signalled by the appropriate
+ * ContextEvent() callback of MAudioContextObserver.
+ * @return An error code. KErrNone on success. KErrNotReady if SetClientSettings() has not been called.
+ */
+ virtual TInt Commit()=0;
+
+ /**
+ * Forget any pending, requested changes made to this context or its components.
+ *
+ * Typically called where the client has started to request changes, has yet to call Commit() and changes its mind.
+ *
+ * @return A system wide error code. KErrNone on success. KErrNotReady if called during Commit() cycle.
+ */
+ virtual TInt Reset()=0;
+
+ /**
+ * Sets the client information used by the underlying MMRC.
+ *
+ * This must be called before any call to Commit(). The client context contains information about the client application
+ * which is utilising the audio functionality, since this will typically be a different process than is calling A3F.
+ *
+ * @param aSettings Essentially the process Id of the client application,
+ * the one whose details are used to determine capabilities and policy.
+ * @return an error code. KErrNone for success, otherwise one of the system-wide error codes.
+ */
+ virtual TInt SetClientSettings(const TClientContextSettings& aSettings)=0;
+
+ /**
+ * A mechanism to obtain extensions to the Context API.
+ *
+ * @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;
+
+ /**
+ * Registers an audio context observer.
+ *
+ * The observer will be notified about context state changes.
+ *
+ * @param aObserver the observer reference to register.
+ * @return An error code. KErrNone on success, otherwise one of the system wide error codes.
+ */
+ virtual TInt RegisterAudioContextObserver(MAudioContextObserver& aObserver) = 0;
+
+ /**
+ * Unregisters an audio context observer.
+ *
+ * @param aObserver the observer reference to unregister.
+ * @return An error code. KErrNone on success, otherwise one of the system wide error codes.
+ */
+ virtual void UnregisterAudioContextObserver(MAudioContextObserver& aObserver) = 0;
+ };
+
+#endif // MAUDIOCONTEXT_H