Class MDataSink

class MDataSink;

Description

Abstract class representing a data sink.

Members

Defined in MDataSink:
BufferFilledL(), CanCreateSinkBuffer(), ConstructSinkL(), CreateSinkBufferL(), DataSinkType(), EmptyBufferL(), MDataSink(), NegotiateL(), NewSinkL(), SetSinkDataTypeCode(), SetSinkPrioritySettings(), SinkCustomCommand(), SinkDataTypeCode(), SinkPauseL(), SinkPlayL(), SinkPrimeL(), SinkStopL(), SinkThreadLogoff(), SinkThreadLogon(), ~MDataSink()

inline virtual ~MDataSink();

Description

Destructor.

protected: inline MDataSink(TUid aType);

Description

Protected constructor.

Parameters

TUid aType The source type UID.

static inline MDataSink *NewSinkL(TUid aImplementationUid, const TDesC8 &aInitData);

Description

Instantiates a new data sink.

Parameters

TUid aImplementationUid The UID identifying the data sink to be instantiated. const TDesC8 &aInitData The sink specific initialisation data required for sink construction.

Return value

MDataSink * A pointer to the instantiated data sink.

inline virtual TUid DataSinkType() const;

Description

Returns the UID identifying the type of data sink.

Return value

TUid The UID identifying the type of data sink

virtual TFourCC SinkDataTypeCode(TMediaId aMediaId)=0;

Description

Returns the data type as a fourCC code of the data sink.

This is a pure virtual function that each derrived class must implement.

Parameters

TMediaId aMediaId This identifies the type of media eg. audio or video and the stream ID. This parameter is required in cases where the sink can accept data of more than one media type and/or multiple streams of data.

Return value

TFourCC The fourCC code identifying the sink datatype for the specified aMediaId.

inline virtual TInt SetSinkDataTypeCode(TFourCC aSinkFourCC, TMediaId aMediaId);

Description

Sets the data type as a fourCC code for the data sink.

This is a virtual function that each derived class can implement if the data sink supports the ability to have its data type set.

Parameters

TFourCC aSinkFourCC This specifies the data type as a fourCC code to set the sink to. TMediaId aMediaId This identifies the type of media eg. audio or video and the stream ID. This parameter is required in cases where the source can supply data of more than one media type and/or multiple streams of data.

Return value

TInt KErrNone if successful, KErrNotSupported if the sink does not support having it's data type set, otherwise a system wide error code.

virtual void EmptyBufferL(CMMFBuffer *aBuffer, MDataSource *aSupplier, TMediaId aMediaId)=0;

Description

Method called by a MDataSource to request the data sink to empty aBuffer of data.

This is a pure virtual function that each derived class must implement. This method is used when a data sink is passively waiting for requests from a supplier ie. a data source to empty a buffer. The data sink must call the BufferEmptiedL member on aSupplier when it has emptied the buffer of it's data. The data sink can either make this callback synchronously or asynchronously.

Parameters

CMMFBuffer *aBuffer The full buffer that needs emptying of it's data. MDataSource *aSupplier The data source that supplied the data. The data sink needs this to make the BufferEmptiedL callback on aSupplier to indicate to the data source that the data sink has finished with the buffer. TMediaId aMediaId This identifies the type of media eg. audio or video and the stream ID. This parameter is required in cases where the source can supply data of more than one media type and/or multiple streams of data.

virtual void BufferFilledL(CMMFBuffer *aBuffer)=0;

Description

Function called by a data source to pass back a filled buffer to the sink.

This is a pure virtual function that each derived class must implement. This method is used as the callback when the data sink actively requests a supplier ie. a data source to fill a buffer by calling the data sources FillBufferL. When the data sink gets this callback it knows that the buffer has been filled and is ready to be emptied.

Parameters

CMMFBuffer *aBuffer The buffer that has been filled by a data source and is now available for processing.

virtual TBool CanCreateSinkBuffer()=0;

Description

Function to indicate whether the data sink can create a buffer.

This is a pure virtual function that each derived class must implement.

Return value

TBool A boolean indicating if the data sink can create a buffer. ETrue if it can otherwise EFalse.

virtual CMMFBuffer *CreateSinkBufferL(TMediaId aMediaId, TBool &aReference)=0;

Description

Returns a buffer created by the data sink.

This is a pure virtual function that each derived class must implement.

Parameters

TMediaId aMediaId This identifies the type of media eg. audio or video and the stream ID. This parameter is required in cases where the source can supply data of more than one media type and/or multiple streams of data. TBool &aReference This must be written to by the method to indicate whether the created buffer is a 'reference' buffer. A 'reference' buffer is a buffer that is owned by the sink and should be used in preference to the source buffer provided the source buffer is also not a reference buffer.

Return value

CMMFBuffer * The created buffer.

inline virtual TInt SinkThreadLogon(MAsyncEventHandler &aEventHandler);

Description

Function to 'logon' the data sink to the same thread that sink will be consuming data in.

This method may be required as the thread that the data sink was created in is not always the same thread that the data transfer will take place in. Therefore any thread specific initialisation needs to be performed in the SinkThreadLogon rather than in the creation of the data sink.

This is a virtual function that a derrived data sink can implement if any thread specific initialisation is required and/or the data sink can create any asynchronous events.

Parameters

MAsyncEventHandler &aEventHandler This is an MAsyncEventHandler to handle asynchronous events that occur during the transfer of multimedia data. The event handler must be in the same thread as the data transfer thread - hence the reason it is passed in the SinkThreadLogon as opposed to say the constructor.

Return value

TInt An error code indicating if the function call was successful. KErrNone on success, otherwise another of the system-wide error codes.

inline virtual void SinkThreadLogoff();

Description

Function to 'logoff' the data sink from the same thread that sink consumes data in.

This method may be required as the thread that the data sink is deleted in may not be the same thread that the data transfer took place in. Therefore any thread specific releasing of resources needs to be performed in the SinkThreadLogoff rather than in the destructor.

This is a virtual function that a derrived data sink can implement if any thread specific releasing of resources is required.

inline virtual void NegotiateL(MDataSource &aDataSource);

Description

Allows the data sink to negotiate with a data source.

This method is required in cases where the settings of data sink are dependant on those of a data source. This is a virtual function that a derrived data sink can implement.

Parameters

MDataSource &aDataSource The data source whose settings can affect the data sink.

inline virtual void SinkPrimeL();

Description

Function to 'prime' the data sink.

This is a virtual function that a derrived data sink can implement if any data sink specific 'priming' is required.

inline virtual void SinkPlayL();

Description

Function 'play' the data sink.

This is a virtual function that a derrived data sink can implement if any data sink specific action is required prior to 'playing' ie. the start of data transfer.

inline virtual void SinkPauseL();

Description

Function to 'pause' the data sink.

This is a virtual function that a derrived data sink can implement if any data sink specific action is required to 'pause'.

inline virtual void SinkStopL();

Description

Function to 'stop' the data sink.

This is a virtual function that a derrived data sink can implement if any data sink specific action is required to 'stop'

Capability:

MultimediaDD

A process requesting or using this method that has MultimediaDD capability will always have precedence over a process that does not have MultimediaDD.

inline virtual void SetSinkPrioritySettings(const TMMFPrioritySettings &aPrioritySettings);

Description

Sets the sink priority settings.

This is a virtual function that a derrived data sink can implement if a priority mechanism is required to arbitrate between multiple clients trying to access the same resource.

Parameters

const TMMFPrioritySettings &aPrioritySettings The sink priority settings.

inline virtual void SinkCustomCommand(TMMFMessage &aMessage);

Description

Calls a sink specific custom command.

This is a virtual function that a derrived data sink can implement if it implements any custom commands.

Parameters

TMMFMessage &aMessage The message specifying the custom command.

protected: virtual void ConstructSinkL(const TDesC8 &aInitData)=0;

Description

Performs any sink construction dependant on the sink construction initialisation data aInitData.

This is a pure virtual function that a derrived data sink must implement

Parameters

const TDesC8 &aInitData The sink specific initialisation data required for sink construction.