--- a/epoc32/include/sensrvchannel.h Tue Nov 24 13:55:44 2009 +0000
+++ b/epoc32/include/sensrvchannel.h Tue Mar 16 16:12:26 2010 +0000
@@ -1,1 +1,472 @@
-sensrvchannel.h
+/*
+* Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members
+* which accompanies this distribution, and is available
+* at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description: Sensor channel class definition
+*
+*/
+
+
+#ifndef SENSRVCHANNEL_H
+#define SENSRVCHANNEL_H
+
+#include <e32base.h>
+#include <sensrvtypes.h>
+#include <sensrvchannelconditionset.h>
+#include <sensrvchannelinfo.h>
+
+
+class MSensrvPropertyListener;
+class MSensrvDataListener;
+class MSensrvChannelConditionListener;
+class CSensrvChannelCondition;
+class CSensrvChannelListener;
+
+
+/**
+* The CSensrvChannel class provides an API that allows clients to open, control, configure,
+* receive data and receive notifications from a sensor channel.
+*
+* When instantiating CSensrvChannel an instance of TSensrvChannelInfo returned by
+* CSensrvChannelFinder::FindChannelsL() must be used. This ensures that internal data used
+* in identifying the chosen channel is passed back to Sensor Services in its entirety
+* therefore ensuring correct operation. Not using the instance returned by
+* CSensrvChannelFinder::FindChannelsL() will result in undefined behaviour.
+*
+* On instantiation of this class a session connection to the Sensor Server is made. The Sensor
+* server is a transient server and is started, if not already running, when a session connection
+* is made. The sensor server is shutdown when a device-configured timeout period expires after
+* the last session connection has been dropped. The Sensor Server will not shutdown if there is
+* a session connection to it.
+*
+* The instance of TSensrvChannelInfo returned by CSensrvChannelFinder::FindChannelsL()
+* contains a channel Id which is only valid for the lifetime of the sensor server. If a client
+* requires that this id remains unchanged then the client must ensure that an instance of either
+* CSensrvChannelFinder or CSensrvChannel remains instantiated. This keeps a session connection with
+* the server open which prevents the sensor server from shutting down.
+*
+* After creating an instance of this class a client would typically:
+* 1. Check the configuration of the channel using GetPropertyL() or GetAllPropertuies().
+* 2. Change the configuration where necessary using SetPropertiesL()
+* 3. If SetPropertiesL() failed, because of higher priority clients of this same channel or higher
+* priority clients of impacted channels on the same sensor, listen for notifications indicating
+* when it is able to set properties using SetPropertyListenerl().
+* 4. Listen for property changes using SetPropertyListenerl(). This notifies the client of property
+* changes made by other clients of this same channel.
+* 5. Listen for data and retrieve data on the channel using StartDataListeningL() and GetData().
+* 6. Set trigger conditions for a 1 off notification when the condition is met using AddConditionL()
+* and SetConditionListeningL().
+*
+* Its possible that there may be more than 1 client using the same sensor channel on the device. Each
+* of these clients will have created their own instance of CSensrvChannel and can attempt to configure
+* the sensor using the SetPropertyL() operation. To manage any contention between clients wishing to
+* change the configuration of the sensor a concept of Client Priorities is employed. This means that a
+* device creator assigns a pre-determined priority to a client. If a client has not been assigned a
+* priority then it is assumed it has the lowest priority.
+*
+* When the SetPropertyL() operation is called the sensor server checks to see if the client has the
+* highest Client Priority of all clients using that channel or using an impacted channel on the same
+* sensor. If it has the property is set and all other clients of the channel are notified of the property
+* change. If it has not the SetPropertyL() operation fails with KErrAccessDenied. If clients have
+* the same priority then property setting is done on a first come first served basis.
+*
+* If a client is unable to set a property because of higher priority clients then the client should
+* implement the MSensrvPropertyListener::SetPropertySuccessIndicationChanged() callback so that they can
+* be notified when they are able to set properties.
+*
+* All client applications should be designed in such a way so that they are able to handle the situation
+* where they are unable to configure a channel using the SetPropertyL() operation.
+*
+* For example:
+* Should application features be disabled or should the application shutdown in such conditions?
+* Should features be disabled under certain channel configurations?
+*
+* This object is closed when deleted either by a call to operator delete or by the cleanup stack. No special
+* cleanup code is necessary to close the object before deletion.
+*
+* @see CSensrvChannelFinder
+* @lib sensrvclient.lib
+* @since S60 5.0
+*/
+
+NONSHARABLE_CLASS( CSensrvChannel ): public CBase
+ {
+ public:
+ /**
+ * Two-phased constructor.
+ *
+ * The Sensor Server uses aChannelInfo to identify the channel in the server that the returned object
+ * represents.
+ *
+ * @since S60 5.0
+ * @param aChannelInfo The information that determines which channel object is created. This must
+ * be an object returned by CSensrvChannelFinder::FindChannelsL().
+ * @return Pointer to created CSensorChannel object
+ * @leave KErrNoMemory
+ * @leave One of the system-wide error codes
+ */
+ IMPORT_C static CSensrvChannel* NewL
+ ( const TSensrvChannelInfo& aChannelInfo );
+
+ /**
+ * Two-phased constructor.
+ *
+ * The Sensor Server uses aChannelInfo to identify the channel in the server that the returned object
+ * represents.
+ *
+ * @since S60 5.0
+ * @param aChannelInfo The information that determines which channel object is created. This must
+ * be an object returned by CSensrvChannelFinder::FindChannelsL().
+ * @return Pointer to created CSensorChannel object that is placed on the cleanup stack.
+ * @leave KErrNoMemory
+ * @leave One of the system-wide error codes
+ */
+ IMPORT_C static CSensrvChannel* NewLC
+ ( const TSensrvChannelInfo& aChannelInfo );
+
+ public:
+ /**
+ * Initializes and opens the channel. After the channel is opened, the client can set and get channel
+ * properties, add channel conditions and listen for sensor data.
+ *
+ * @since S60 5.0
+ * @leave KErrAlreadyExists if channel is already open
+ * @leave One of the system-wide error codes
+ */
+ virtual void OpenChannelL() = 0;
+
+ /**
+ * Closes the channel.
+ *
+ * This object is closed when deleted either by a call to operator delete or by the cleanup stack. No special
+ * cleanup code is necessary to close the object before deletion.
+ *
+ * @since S60 5.0
+ * @return KErrNone if channel closing is successful, or one of the system-wide error codes
+ */
+ virtual TInt CloseChannel() = 0;
+
+ /**
+ * Retrieves a channel information object related to this channel.
+ *
+ * @since S60 5.0
+ * @return Reference to the channel information object
+ */
+ virtual const TSensrvChannelInfo& GetChannelInfo() const = 0;
+
+ /**
+ * Starts channel data listening on the channel.
+ *
+ * To use this operation clients must provide an object that inherits from MSensrvDataListener.
+ *
+ * When new data is available to be read, the client is notified by the
+ * MSensrvDataListener::DataReceived() callback. On receiving this notificaton the client should
+ * retrieve the data using the GetData() operation.
+ *
+ * Note that if a client is listening for both data and conditions on the channel then the lower
+ * desired count and buffering period provided in either start listening operation arguments will be
+ * used for both listeners. When either listener is stopped neither the desired count nor the
+ * buffering period shall be changed.
+ *
+ * For the best performance, always use the highest desired count and maximum count as the use case
+ * allows. This will reduce the overhead caused by a high volume of IPC context switches. However,
+ * be aware that higher counts need to reserve more memory.
+ *
+ * @since S60 5.0
+ * @param aDataListener Data listener for the channel. Must be valid until data listening is stopped.
+ * @param aDesiredCount Desired receiving buffer size defined as a count of the channel data objects.
+ * The maximum value is determined by sensor server internal channel buffer size, and minimum
+ * value is one. Any value outside these limits is interpreted as maximum possible value.
+ * The actual count of channel data objects received may be smaller than aDesiredCount, if a
+ * non-zero buffering period has been specified.
+ * The actual count of channel data objects received may larger, if aMaximumCount is bigger
+ * than aDesiredCount.
+ * If the sensor supplies data sporadically, and the clients requires every data object then
+ * aDesiredCount should be set to one to ensure that no data objects are missed.
+ * @param aMaximumCount Maximum receiving buffer size defined as a count of the channel data object.
+ * The Maximum value is determined by sensor server internal channel buffer size, and minimum
+ * value is aDesiredCount. Any value outside these limits is interpreted as maximum possible
+ * value.
+ * It is recommended that whenever aDesiredCount needs to be low and sensor has relatively high
+ * data rate, aMaximumCount is set to significantly higher than aDesiredCount to reduce IPC
+ * context switches and data loss.
+ * @param aBufferingPeriod Specifies the maximum time in milliseconds that sensor server waits before
+ * notifying the client that new data is available. It is possible that no new data is will be
+ * available when the client is notified.
+ * Zero timeout means that only desired and maximum counts are used in getting data.
+ * Using a buffering period results in lot of unnecessary IPC context switches if a sensor
+ * channel supplies data sporadically. It is therefore recommended that a buffering period is
+ * used only when it is absolutely vital to have data at specific intervals and using a low
+ * desired count is otherwise too expensive performance-wise.
+ * @leave KErrArgument if aDataListener is NULL, or if a negative argument is supplied
+ * @leave KErrNotFound if the channel is not open
+ * @leave KErrAlreadyExists if data listening has already started on the channel
+ * @leave One of the system-wide error codes
+ */
+ virtual void StartDataListeningL( MSensrvDataListener* aDataListener,
+ const TInt aDesiredCount,
+ const TInt aMaximumCount,
+ const TInt aBufferingPeriod ) = 0;
+
+ /**
+ * Stop channel data listening.
+ *
+ * @since S60 5.0
+ * @return KErrNone if stopping successful or one of the system-wide error codes
+ */
+ virtual TInt StopDataListening() = 0;
+
+ /**
+ * Get data items when the client is notified by the MSensrvDataListener::DataReceived() callback
+ * that new data is ready to be retrieved. The callback also indicates the number of data items
+ * contained in aData.
+ *
+ * Example:
+ *
+ * How to retrieve data using TPckg
+ *
+ * @code
+ * void DataReceived(CSensrvChannel& aChannel, TInt aCount, TInt aDataLost )
+ * {
+ * if(aChannel.GetChannelInfo().iChannelType == KSensrvChannelTypeIdAccelerometerXYZAxisData)
+ * {
+ * TSensrvAccelerometerAxisData XYZData;
+ * TPckg<TSensrvAccelerometerAxisData> XYZPackage( XYZData );
+ * aChannel.GetData( XYZPackage );
+ * }
+ * }
+ * @endcode
+ *
+ * @since S60 5.0
+ * @param aData Reference to descriptor that contains the data. Typically this is a package buffer
+ * defined for data type of this channel. See channel specific data headers for details of
+ * the package types and data supported by a channel.
+ * @return KErrNotFound if data buffer is empty, KErrOverflow if aData is wrong size for data
+ * item, or one of the system-wide error codes
+ */
+ virtual TInt GetData( TDes8& aData ) = 0;
+
+ /**
+ * Sets a property value for this channel. To manage any contention between multiple clients wishing
+ * to change the configuration of the sensor a concept of Client Priorities is employed. See class
+ * description for further information.
+ *
+ * The sensor plugin may police setting of properties by verifying that the client making the request
+ * has the necessary capabilities. If the client does not then it will return with KErrAccessDenied.
+ * @since S60 5.0
+ * @param aProperty Identifies the property that is to be set and its new value. Only the Property Id,
+ * Item Index and Property Value should be filled in. All other fields in TSensrvProperty are
+ * ignored.
+ * @return KErrNotFound if channel is not open or if the property does not exist, KErrAccessDenied
+ * if there are other clients for this channel or impacted channel on the same sensor with a
+ * higher Client Priority, KErrAccessDenied if the client does not have the required
+ * capabilities or one of the system-wide error codes
+ */
+ virtual TInt SetProperty( const TSensrvProperty& aProperty ) = 0;
+
+ /**
+ * Gets a channel property value for this channel.
+ *
+ * @since S60 5.0
+ * @param aPropertyId Id of the property that is to be retrieved
+ * @param aItemIndex The Item Index of the property to be retrieved. This is mapped to a specific item
+ * in channel data structure. See channel specific data headers.
+ * @param aProperty Reference for a property object where property data is to be copied
+ * @leave KErrNotFound if channel is not open
+ * @leave KErrNotFound if property does not exist
+ * @leave KErrArgument if a negative argument is supplied
+ * @leave One of the system-wide error codes
+ * */
+ virtual void GetPropertyL( const TSensrvPropertyId aPropertyId,
+ const TInt aItemIndex,
+ TSensrvProperty& aProperty ) = 0;
+
+ /**
+ * Get a channel property value for this channel
+ *
+ * @since S60 5.0
+ * @param aPropertyId Id of the property that is to be retrieved
+ * @param aItemIndex Item Index of the property to be retrieved. This is mapped to a specific item
+ * in channel data structure. See channel specific data headers.
+ * @param aArrayIndex Array index of the property to be retrieved when the property is part of a
+ * property array.
+ * @param aProperty Reference for a property object where property data is to be copied
+ * @leave KErrNotFound if channel is not open
+ * @leave KErrNotFound if property does not exist
+ * @leave KErrArgument if a negative argument is supplied
+ * @leave One of the system-wide error codes
+ */
+ virtual void GetPropertyL( const TSensrvPropertyId aPropertyId,
+ const TInt aItemIndex,
+ const TInt aArrayIndex,
+ TSensrvProperty& aProperty ) = 0;
+
+ /**
+ * Get all properties for this channel
+ *
+ * @since S60 5.0
+ * @param aChannelPropertyList Reference for a property list where all property data is to be
+ * copied. Any existing data in the list will be lost.
+ * @leave KErrNotFound if channel is not open
+ * @leave One of the system-wide error codes
+ */
+ virtual void GetAllPropertiesL
+ ( RSensrvPropertyList& aChannelPropertyList ) = 0;
+
+ /**
+ * Get all channel properties having the supplied Property Id. This is used when the property
+ * is an array property.
+ *
+ * @since S60 5.0
+ * @param aPropertyId Id of the property to be retrieved
+ * @param aChannelPropertyList Reference for a property list where all property data is to be
+ * copied. Any existing data in the list will be lost.
+ * @leave KErrNotFound if channel is not open
+ * @leave KErrNotFound if property does not exist
+ * @leave One of the system-wide error codes
+ */
+ virtual void GetAllPropertiesL
+ ( const TSensrvPropertyId aPropertyId,
+ RSensrvPropertyList& aChannelPropertyList ) = 0;
+
+ /**
+ * Start property listening on this channel.
+ *
+ * To use this operation clients must provide an object that inherits from MSensrvPropertyListener.
+ *
+ * The client can use the property listener to get notifications when properties are changed and
+ * to get a notification when the client is able/unable to set properties because of higher priority
+ * clients have opened/closed the same sensor channel.
+ *
+ * If the client itself changes a property value, no notification is received for that property by
+ * the client. If another client changes a property on this channel or another channel that impacts
+ * this channel a notification will be received by the client.
+ *
+ * Some sensors support a number of channels with each channel having some common properties.
+ * Therefore changing a common property may result in notifications on a number of other channels
+ * supported by the sensor.
+ *
+ * @since S60 5.0
+ * @param aChannelPropertyListener Pointer to channel property listener callback instance. The
+ * channel property listener must be valid until the CSensrvChannel object is destroyed or
+ * listening has been stopped. Listening can be stopped using a NULL parameter.
+ * @leave KErrAlreadyExists if channel property listener has already been set
+ * @leave KErrNotFound if channel is not open
+ * @leave One of the system-wide error codes
+ */
+ virtual void SetPropertyListenerL
+ ( MSensrvPropertyListener* aChannelPropertyListener ) = 0;
+
+ /**
+ * Add a channel ConditionSet to the channel.
+ *
+ * Channel ConditionSet's are used for channel condition listening and at least 1 ConditionSet must
+ * be added before listening can begin.
+ *
+ * When the conditions defined by the ConditionSet is met the client will be notified by the
+ * MSensrvChannelConditionListener::ConditionMet() callback and listening for this ConditionSet will
+ * cease. If a client wishes to listen for this ConditionSet again it must be added again.
+ *
+ * The client continues to own the ConditionSet object after a call to this function and must ensure
+ * that it is destroyed when no longer required.
+ *
+ * The client must ensure that the ConditionSet object is valid until it is no longer needed by the
+ * Sensor Server. This is either after the condition set has been removed by the client using
+ * RemoveConditionL() or the client has been notified that the condition has been met.
+ *
+ * @since S60 5.0
+ * @param aChannelConditionSet The channel condition set to be added.
+ * @leave KErrNotFound if channel is not open
+ * @leave KErrNotSupported if a channel does not support conditions.
+ * @leave One of the system-wide error codes
+ * @see CSensrvChannel::StartConditionListeningL()
+ */
+ virtual void AddConditionL( CSensrvChannelConditionSet& aChannelConditionSet ) = 0;
+
+ /**
+ * Remove a channel ConditionSet from the channel.
+ *
+ * The same reference used to to add the Condition Set in AddConditionL(), must also be used to
+ * remove it.
+ *
+ * The removed channel ConditionSet is no longer used for channel condition listening.
+ *
+ * The client continues to own the ConditionSet object after a call to this function and must ensure
+ * that it is destroyed when no longer required.
+ *
+ * @since S60 5.0
+ * @param aChannelConditionSet The channel condition set to be removed.
+ * @leave KErrNotFound if channel is not open
+ * @leave One of the system-wide error codes
+ */
+ virtual void RemoveConditionL
+ ( CSensrvChannelConditionSet& aChannelConditionSet ) = 0;
+
+ /**
+ * Start channel condition listening.
+ *
+ * To use this operation clients must provide an object that inherits from MSensrvChannelConditionListener.
+ *
+ * If the conditions of an added ConditionSet is met the MSensrvChannelConditionListener::ConditionMet()
+ * callback function will be called and listening for this ConditionSet will cease. If a client wishes
+ * to listen for the same ConditionSet again it must be added again.
+ *
+ * Note that if a client is listening for both data and conditions on the channel then the lower
+ * desired count and buffering period provided in either start listening operation arguments will be
+ * used for both listeners. When either listener is stopped neither the desired count nor the
+ * buffering period shall be changed.
+ *
+ * @since S60 5.0
+ * @param aChannelConditionListener Condition listener for the channel. Must be valid until data
+ * listening is stopped.
+ * @param aObjectCount Listening buffer size defined as a count of the channel data objects. When the
+ * desired object count is reached each ConditionSet is evaluated in turn. The maximum value is
+ * determined by sensor server internal channel buffer size, and minimum value is one. Any value
+ * outside these limits is interpreted as maximum possible value.
+ * @param aBufferingPeriod Specifies the maximum time in milliseconds that sensor server waits before
+ * evaluating new data.
+ * Zero timeout means that the sensor server only evaluates new data when the object count has been
+ * reached.
+ * @leave KErrArgument if aChannelConditionListener is NULL, or if a negative argument is supplied
+ * @leave KErrNotFound if the channel is not open
+ * @leave KErrAlreadyExists if condition listening has already started on the channel
+ * @leave One of the system-wide error codes
+ */
+ virtual void StartConditionListeningL
+ ( MSensrvChannelConditionListener* aChannelConditionListener,
+ const TInt aObjectCount,
+ const TInt aBufferingPeriod ) = 0;
+
+ /**
+ * Stop channel condition listening.
+ *
+ * All remaining unmet ConditionSet's are removed and channel condition listening is stopped.
+ *
+ * If the same ConditionSet's need to be used when condition listening has been restarted then they must be
+ * re-added.
+ *
+ * @since S60 5.0
+ * @return KErrNone if condition listening is successfully stopped or one of the system-wide error codes
+ */
+ virtual TInt StopConditionListening() = 0;
+
+ public:
+ /**
+ * Default constructor.
+ */
+ CSensrvChannel();
+ };
+
+
+#endif //SENSRVCHANNEL_H
+
+// End of File