Symbian
Symbian OS Library

SYMBIAN OS V9.3

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Location: MTSR.H
Link against: msgs.lib
Link against: msgs_autoshutdown.lib

Class CBaseServerMtm

class CBaseServerMtm : public CActive;

Description

Base class for Server-side MTM components. Server-side MTMs provide all message transport functionality for a particular messaging protocol.

MTM implementers implement a derived class to provide such functionality for their message protocol. Writers of message client applications are never concerned with this class and its sub-classes, as these are only accessed by the Message Server.

Each MTM interprets the generic commands in different ways. For example, a Fax MTM would transmit a fax when asked to copy a fax from a local folder to a fax service. For the same function, an IMAP MTM would create a copy of the message on the remote server and update the message index to show the copy of the message on the remote server. An important initial design task is to the map the functions to the functionality provided by the protocol.

Server-side MTM functions are called by the Message Server as a result of a client request that requires some remote operation with the MTM's protocol. The following steps give a simplified view of the usual sequence of events:

1. the Message Server instantiates a Server-side MTM object through the factory function

2. the Message Server calls the appropriate asynchronous function on the Server-side MTM interface, passing a TRequestStatus argument

3. the Server-side MTM function typically starts whatever asynchronous communications it requires and returns

4. the Server-side MTM is signalled when the asynchronous communications complete, and handles the result

5. the Server-side MTM signals the Message Server, through the TRequestStatus passed earlier

6. the Message Server deletes the Server-side MTM object

To qualify this somewhat:

1. it is up to the Server-side MTM implementation to decide how to translate data back and forth between the formats used by Message Server (index entry, message store, binary files), and that required by the protocol; this is another important design task

2. depending on the protocol being used, the communications sequence can be of considerable complexity; typically it requires division into a number of asynchronous steps

3. for greater efficiency where further commands are shortly expected, deletion of the Server-side MTM object can be prevented

For asynchronous requests, a Server-side MTM should always complete the TRequestStatus with KErrNone. Any errors should be returned in the progress information.

Note the following significant groups of functions:

1. Copy and move from remote functions: CopyToLocalL() and MoveToLocalL() are called by the Message Server to get a selection of entries from a remote location. For many protocols, this should be interpreted as message retrieval. For protocols where messages exist on a remote server, this function is typically used to download specific messages, after an initial connection has downloaded message headers.

2. Copy and move to remote functions: CopyFromLocalL() and MoveFromLocalL() are called by the Message Server to copy/move a selection of entries to a remote location. For many protocols, this should be interpreted as message sending.

3. Copy and move within remote functions: CopyWithinServiceL() and MoveWithinServiceL() are called by the Message Server to copy a selection of entries within a remote service. An example of their use might be for a user rearranging messages within remote folders.

Derivation

Members

Defined in CBaseServerMtm:
CBaseServerMtm(), ChangeL(), CommandExpected(), CopyFromLocalL(), CopyToLocalL(), CopyWithinServiceL(), CreateL(), DeleteAllL(), DoComplete(), DoRunL(), Extension_(), GetInterface(), MoveFromLocalL(), MoveToLocalL(), MoveWithinServiceL(), Progress(), RunError(), RunL(), StartCommandL(), SystemProgress(), iServerEntry, ~CBaseServerMtm()

Inherited from CActive:
Cancel(), Deque(), DoCancel(), EPriorityHigh, EPriorityIdle, EPriorityLow, EPriorityStandard, EPriorityUserInput, IsActive(), IsAdded(), Priority(), SetActive(), SetPriority(), TPriority, iStatus

Inherited from CBase:
Delete(), operator new()


Construction and destruction


~CBaseServerMtm()

IMPORT_C ~CBaseServerMtm();

Description

Destructor.

This cleans up the base class. CBaseServerMtm-derived objects are deleted by the Message Server when they are no longer required.

Derived classes can implement a destructor to do any additional clean up tasks that they require.


CBaseServerMtm()

protected: IMPORT_C CBaseServerMtm(CRegisteredMtmDll &aRegisteredMtmDll, CMsvServerEntry *aServerEntry);

Description

Constructor.

The function is passed a CMsvServerEntry object in aServerEntry. This object is used to access and change Message Server entries. Its context is initially set either to the parent of the entry or selection being operated on, or the entry itself. The constructor stores it in the protected iServerEntry member.

Derived classes can implement a constructor to perform any additional MTM-specific setup that can be safely carried out in a constructor. Such constructors must call the base class constructor function.

Parameters

CRegisteredMtmDll &aRegisteredMtmDll

Registration data for the MTM DLL

CMsvServerEntry *aServerEntry

Context on which to operate

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Member functions


CopyToLocalL()

virtual void CopyToLocalL(const CMsvEntrySelection &aSelection, TMsvId aDestination, TRequestStatus &aStatus)=0;

Description

Copies a selection of entries from a remote location to a local location. This will only be meaningful for some protocols.

Requirements:

Implementations should provide this function if the messaging protocol supports retrieval of remote entries. If this is not supported, implementations should leave with KErrNotSupported.

Implementations of this function have three fundamental steps:

1. doing the transfer operation using the appropriate communications protocols

2. converting protocol-specific data into the three-part storage format (index entry, message store, binary files) required by the Message Server

3. updating entries in the Message Server

Parameters

const CMsvEntrySelection &aSelection

The collection of message index entries for which the copy/moving is required.

TMsvId aDestination

The entry ID to which the selection is to be copied

TRequestStatus &aStatus

Asynchronous completion word for the operation

Leave codes

KErrNotSupported

The Server-side MTM does not support this operation

Other

leave codes Dependent on implementation


CopyFromLocalL()

virtual void CopyFromLocalL(const CMsvEntrySelection &aSelection, TMsvId aDestination, TRequestStatus &aStatus)=0;

Description

Copies a selection of entries from a local location to a remote location.

Requirements:

Implementations should provide this function if the messaging protocol supports retrieval of remote entries. If this is not supported, implementations should leave with KErrNotSupported.

Implementations of this function have three fundamental steps:

1. reading entry data

2. converting entry data from the Message Server format into that required by the protocol

3. doing the transfer operation using the appropriate communications protocols

Parameters

const CMsvEntrySelection &aSelection

The collection of message index entries for which the copy is required

TMsvId aDestination

The entry ID of the service by which the entries should be transferred

TRequestStatus &aStatus

Asynchronous completion word for the operation

Leave codes

KErrNotSupported

The Server-side MTM does not support this operation

Other

leave codes Dependent on implementation


CopyWithinServiceL()

virtual void CopyWithinServiceL(const CMsvEntrySelection &aSelection, TMsvId aDestination, TRequestStatus &aStatus)=0;

Description

Copies a selection of entries within a remote location.

Requirements:

Implementations should provide this function if the messaging protocol supports the ability to copy entries within a remote service. If this is not supported, implementations should leave with KErrNotSupported.

Parameters

const CMsvEntrySelection &aSelection

The collection of message index entries for which the copy is required

TMsvId aDestination

The server entry ID to which the selection is to be copied

TRequestStatus &aStatus

Asynchronous completion word for the operation

Leave codes

KErrNotSupported

The Server-side MTM does not support this operation

Other

leave codes Dependent on implementation


DeleteAllL()

virtual void DeleteAllL(const CMsvEntrySelection &aSelection, TRequestStatus &aStatus)=0;

Description

Deletes each entry in the supplied selection when called by the message Server. If any of the entries in the selection is a parent entry, then all its children should also be deleted, recursively to the bottom of the ownership tree.

Implementations should provide this function if the messaging protocol supports deletion of remote entries. If this is not supported, implementations should leave with KErrNotSupported.

Parameters

const CMsvEntrySelection &aSelection

The collection of entries that are to be deleted.

TRequestStatus &aStatus

Asynchronous completion object.

Leave codes

KErrNotSupported

The Server-side MTM does not support this operation

Other

leave codes Dependent on implementation


CreateL()

virtual void CreateL(TMsvEntry aNewEntry, TRequestStatus &aStatus)=0;

Description

Creates a new remote entry with relevant data when called by the Message Server.

Implementations should provide this function if the messaging protocol supports creation of remote entries. If this is not supported, implementations should leave with KErrNotSupported.

As with ChangeL(), the Server-side MTM implementation must decide what information in the TMsvEntry is relevant to the remote entry, and translate it appropriately for the specific protocol. Most of the data contained in the TMsvEntry is specific to the Message Server, and would probably have no direct correlation with the protocol's own storage format. For example, for a folder, probably only the name and parent are needed, so if the protocol supports creation of remote folders, the implementation could:

1. check for a folder type entry

2. get the folder name and parent details from aNewEntry

3. initiate a protocol-specific action to create the remote folder

Parameters

TMsvEntry aNewEntry

Data by which to create entry

TRequestStatus &aStatus

Asynchronous completion word for the operation.

Leave codes

KErrNotSupported

The Server-side MTM does not support this operation

Other

leave codes Dependent on implementation


ChangeL()

virtual void ChangeL(TMsvEntry aNewEntry, TRequestStatus &aStatus)=0;

Description

Updates a remote entry with relevant data when called by the Message Server.

Implementations should provide this function if the messaging protocol supports updating of remote entries. If this is not supported, implementations should leave with KErrNotSupported.

The Server-side MTM implementation must decide what information in the TMsvEntry is relevant to the remote entry, and translate it appropriately for the specific protocol. Most of the data contained in the TMsvEntry is specific to the Symbian OS Message Server, and would probably have no direct correlation with the protocol's own storage format. Some entry data may however be useful. For example, if the protocol supports remote renaming of folders, the implementation could:

1. check for a folder type entry

2. extract the folder name from aNewEntry.iDetails

3. check if the folder name has changed by comparing the new name with iDetails in the index entry currently; if not, complete with KErrNone

4. initiate a protocol-specific action to rename the remote folder

The implementation should also always update the local Message Server index through CMsvServerEntry::ChangeL().

Parameters

TMsvEntry aNewEntry

Data by which to update entry

TRequestStatus &aStatus

Asynchronous completion word for the operation.

Leave codes

KErrNotSupported

The Server-side MTM does not support this operation

Other

leave codes Dependent on implementation


StartCommandL()

virtual void StartCommandL(CMsvEntrySelection &aSelection, TInt aCommand, const TDesC8 &aParameter, TRequestStatus &aStatus)=0;

Description

Executes an MTM-specific operation on a selection of entries when called by the Message Server.

The call is made as a response to a client program invoking an MTM-specific operation through CBaseMtm::InvokeSyncFunctionL()/InvokeAsyncFunctionL(). The aSelection, aCommand, and aParameter arguments pass the values of the original aSelection, aFunctionId, and aParameter respectively arguments from such a call. The use (if any) of the aSelection and aParameter arguments by the function depends on the command.

Parameters

CMsvEntrySelection &aSelection

A selection of message entries on which the command is to be executed

TInt aCommand

The MTM-specific command to be carried out

const TDesC8 &aParameter

Command-specific parameters

TRequestStatus &aStatus

Asynchronous completion word for the operation


CommandExpected()

virtual TBool CommandExpected()=0;

Description

Tests if the Server-side MTM object should be deleted when called by the Message Server

It is useful to stop the MTM being deleted when more commands are expected shortly. This would be the case, for example, after receiving a command to go online.

If there are no more commands expected by the Server-side MTM object, then the function should return EFalse, and the Message Server will delete it.

Return value

TBool

ETrue: the MTM object should not be deleted EFalse: the MTM object can be deleted


Progress()

virtual const TDesC8 &Progress()=0;

Description

This function is called by the Message Server to get progress information for the current asynchronous operation.

The call is made as a response to a client program requesting progress information through CMsvOperation::ProgressL(). The packing format used in the TDesC8 is MTM-specific. Only the implementation of the User Interface MTM progress information functions need to understand the format.

The progress buffer should have a maximum size of 256 bytes.

Return value

const TDesC8 &

Progress information on current asynchronous operation

See also:


MoveToLocalL()

virtual void MoveToLocalL(const CMsvEntrySelection &aSelection, TMsvId aDestination, TRequestStatus &aStatus)=0;

Description

Moves a selection of entries from a remote location to a local location.

Requirements:

Implementations should provide this function if the messaging protocol supports retrieval of remote entries. If this is not supported, implementations should leave with KErrNotSupported.

Implementations of this function have three fundamental steps:

1. doing the transfer operation using the appropriate communications protocols

2. converting protocol-specific data into the three-part storage format (index entry, message store, binary files) required by the Message Server

3. updating entries in the Message Server

MoveToLocalL() should differ from CopyToLocalL() in additionally deleting the original remote data.

Parameters

const CMsvEntrySelection &aSelection

The collection of message index entries for which the moving is required.

TMsvId aDestination

The entry ID to which the selection is to be copied/moved

TRequestStatus &aStatus

Asynchronous completion word for the operation

Leave codes

KErrNotSupported

The Server-side MTM does not support this operation

Other

leave codes Dependent on implementation


MoveFromLocalL()

virtual void MoveFromLocalL(const CMsvEntrySelection &aSelection, TMsvId aDestination, TRequestStatus &aStatus)=0;

Description

Moves a selection of entries from a local location to a remote location.

Requirements:

Implementations should provide this function if the messaging protocol supports retrieval of remote entries. If this is not supported, implementations should leave with KErrNotSupported.

Implementations of this function have three fundamental steps:

1. reading entry data

2. converting entry data from the Message Server format into that required by the protocol

3. doing the transfer operation using the appropriate communications protocols

The implementation of MoveFromLocalL() should differ from CopyFromLocalL() in additionally deleting the original local data.

Parameters

const CMsvEntrySelection &aSelection

The collection of message index entries for which the move is required

TMsvId aDestination

The entry ID of the service by which the entries should be transferred

TRequestStatus &aStatus

Asynchronous completion word for the operation

Leave codes

KErrNotSupported

The Server-side MTM does not support this operation

Other

leave codes Dependent on implementation


MoveWithinServiceL()

virtual void MoveWithinServiceL(const CMsvEntrySelection &aSelection, TMsvId aDestination, TRequestStatus &aStatus)=0;

Description

Moves a selection of entries within a remote location.

Requirements:

Implementations should provide this function if the messaging protocol supports the ability to move entries within a remote service. If this is not supported, implementations should leave with KErrNotSupported.

The implementation of MoveWithinServiceL() should differ from CopyWithinServiceL() in additionally deleting the original data.

Parameters

const CMsvEntrySelection &aSelection

The collection of message index entries for which the move is required

TMsvId aDestination

The server entry ID to which the selection is to be moved

TRequestStatus &aStatus

Asynchronous completion word for the operation

Leave codes

KErrNotSupported

The Server-side MTM does not support this operation

Other

leave codes Dependent on implementation


SystemProgress()

IMPORT_C TInt SystemProgress(TMsvSystemProgress &aOutSysProg);

Description

This call leads to calling one of the server Mtms to populate the TMsvSystemProgress structure.

Parameters

TMsvSystemProgress &aOutSysProg

The TMsvSystemProgress structure to be populated by the server

Return value

TInt

the error of the Extension_ method call


DoRunL()

protected: virtual void DoRunL()=0;

Description

Handles the completion of any asynchronous requests that it makes. It is called from the base class RunL() .

Note that any leaves made by this function result in DoComplete() being called with the leave code.


DoComplete()

protected: virtual void DoComplete(TInt aError)=0;

Description

Called by the base class RunL() if DoRunL() leaves.

It should be implemented to handle this error. For example, progress information could be updated to reflect the problem.

Parameters

TInt aError

The leave code given by DoRunL().


Extension_()

protected: virtual IMPORT_C TInt Extension_(TUint aExtensionId, TAny *&a0, TAny *a1);

Description

The extension method provides a polymorphic behaviour to call the correct SystemProgress function.

Parameters

TUint aExtensionId

The Uid passed in as KUIDMsgMsvSystemProgress to obtain the System Progress.

TAny *&a0

TAny *a1

Return value

TInt

KErrExtensionNotSupported retuned if no Extension_ function is overriddden by the derived class.


RunL()

private: virtual IMPORT_C void RunL();

Description

Provides a simple implementation of CActive::RunL() that calls the derived class's DoRunL() function. If that function leaves, then the leave is trapped, and DoComplete() is called to handle the error.

This implementation ensures that derived classes handle leave errors in RunL(), rather than the default of the error being passed to the active scheduler.


RunError()

private: virtual IMPORT_C TInt RunError(TInt aError);

Description

Handles the cases where RunL is leaving.

Parameters

TInt aError

Return value

TInt


GetInterface()

protected: virtual IMPORT_C TAny *GetInterface(TUid aUid);

Description

Returns a pointer to the interface with the specified Uid.

This method is the first part of an extension pattern to allow for more functionality to be supported without adding virtual methods to this base class.

The default implementation returns a NULL pointer.

Parameters

TUid aUid

Uid of the extension interface

Return value

TAny *

Pointer to the extension interface

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Member data


iServerEntry

protected: CMsvServerEntry * iServerEntry;

Description

The entry on which to operate. It is set in the constructor.

The destructor deletes this member.