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Section Contents
Applications that use this class will not work correctly on a version of EPOC earlier than ER5.
CBase |
Abstract: CBase behaviour |
CActive |
Abstract: active object abstraction |
msvapi.h
mcld.lib
This is an abstract base class, derived from CActive, which defines an interface for use by objects which control asynchronous commands in the messaging system. Such objects are returned by CMsvEntry and User Interface MTM functions that complete asynchronously. The interface allows clients to:
The client only needs to understand the CMsvOperation interface, not the concrete implementation used.
As the base class interface for User Interface MTMs, CBaseUiMtm, defines functions that return CMsvOperation objects for control of asynchronous operations, implementers of these MTM components are required to provide suitable derived classes. For example, if CBaseUiMtm::EditL() is implemented to provide message editing, a CMsvOperation -derived class would be provided that completes when the editing operation is complete.
Concrete derived classes must provide implementations of the pure virtual DoCancel() and RunL() functions defined by CActive. DoCancel() should be provided in the normal way to cancel the operation. RunL() should, in addition to any other required functionality, always end by signalling the client that the operation is complete with a suitable completion code.
CMsvOperation(CMsvSession& aSession, TInt aPriority, TRequestStatus& aObserverRequestStatus);
CMsvOperation-derived objects are not created by message client applications. MTM implementers should call this base class constructor from the derived class constructor.
The constructor uses the CMsvSession object to obtain a ID for the operation. This ID can be accessed by clients through Id().
aPriority is the priority used by the active object. Typically, this is EPriorityStandard.
aObserverRequestStatus is the asynchronous status object of an active object provided by the caller. The derived class is required to signal the caller through this when the operation completes. It is stored by the constructor in the iObserverRequestStatus member.
CMsvSession& aSession |
Session object |
TInt aPriority |
Active object priority |
TRequestStatus& aObserverRequestStatus |
Request status of operation observer |
~CMsvOperation();
CMsvOperation-derived objects must be deleted by client applications when they are no longer required. This base class function takes no action. Derived classes should implement a destructor to do the clean up tasks that they require. Minimally, they should call Cancel() to cancel any outstanding request.
const TDesC8& ProgressL()=0;
Use this function to get information on the progress of the operation. The information is returned in a package buffer.
All operations on local entries share the same progress information format, which defined by TMsvLocalOperationProgress.
For MTM-specific operations, progress information can be extracted by calling CBaseUiMtm::GetProgress() or displayed by CBaseUiMtm::DisplayProgressSummary() on the appropriate User Interface MTM.
Derived classes should implement this function so that the client can check on the progress of the operation. The function should share an understanding of the format of the buffer with the implementations of CBaseUiMtm::GetProgress() and CBaseUiMtm::DisplayProgressSummary() in the User Interface MTM. The arguments of CBaseUiMtm::GetProgress() show some information that should be included where appropriate.
const TDesC8& |
Descriptor holding progress information |
KErrNotReady |
The operation has not yet been started: it has been queued for execution in the Message Server |
TMsvOp Id() const;
Use this function to get the operation ID. This ID is unique within a Message Server session. The ID allows the client to keep track of different operations.
TMsvOp |
The ID of the operation |
TUid Mtm() const;
Use this function to get the UID of the MTM associated with the operation.
This UID can be used to determine the appropriate method of getting information from a progress descriptor. See ProgressL().
If the operation is not associated with a service, it returns KUidMsvLocalServiceMtm
TUid |
The UID of the MTM associated with the operation |
TMsvId Service() const;
Returns the ID of the service that is associated with this operation.
If the operation is not associated with a service, the function returns KMsvLocalServiceIndexEntryId.
TMsvId |
ID of the service associated with the operation |
TMsvId iService |
The ID of the service that is associated with this operation. Usually, the derived class constructor will contain a suitable argument to allow the caller to set this. See also Service(). |
TUid iMtm |
The UID of the MTM associated with the operation. The appropriate value should be set by the derived class constructor. See also Mtm(). |
TRequestStatus& iObserverRequestStatus |
Request status of the operation observer. This is the aObserverRequestStatus passed in the constructor. |
CMsvSession& iMsvSession |
Message Server session used by object. This is set by the constructor. |
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