Class REComSession

class REComSession : public RSessionBase;

Description

The REComSession singleton class provides an API to identify (resolution), instantiate, and destroy interface class implementations requested by ECOM clients. It manages the session connection to the ECOM Server itself so that typically only one connection is made to the ECOM Server per thread. It provides an un-initialise function where it releases memory and handles of unused plug-ins, see the FinalClose() function. It also ensures that all necessary clean-up is performed in the event of a Leave by any of the ListImplementationsL() or CreateImplementationL() methods.

Note: Although a public default constructor is provided in this class it is strongly recommended this object is never created by users of this API on the stack or heap by value. To access the non-static methods of this API use the static OpenL() method to obtain a pointer or a reference to the single reference counted session in use. Close() must be called when finished with.

Derivation

• RHandleBase - A handle to an object

• RSessionBase - Client-side handle to a session with a server

• REComSession - The REComSession singleton class provides an API to identify (resolution), instantiate, and destroy interface class implementations requested by ECOM clients

Members

Defined in REComSession:
CancelNotifyOnChange(), Close(), CreateImplementationL(), CreateImplementationL(), CreateImplementationL(), CreateImplementationL(), CreateImplementationL(), CreateImplementationL(), CreateImplementationL(), CreateImplementationL(), CreateImplementationL(), CreateImplementationL(), CreateImplementationL(), CreateImplementationL(), DestroyedImplementation(), FinalClose(), ListImplementationsL(), ListImplementationsL(), ListImplementationsL(), NotifyOnChange(), OpenL(), REComSession()

Inherited from RHandleBase:
Attributes(), Duplicate(), FullName(), Handle(), HandleInfo(), Name(), SetHandle(), SetHandleNC(), iHandle

Inherited from RSessionBase:
CreateSession(), EAutoAttach, EExplicitAttach, Open(), Send(), SendReceive(), SetReturnedHandle(), ShareAuto(), ShareProtected(), TAttachMode

See also:

• REComSession::FinalClose()

IMPORT_C REComSession();

Description

static IMPORT_C REComSession &OpenL();

Description

This method returns a reference to the singleton client/server session object maintained by the ECOM client library, referenced counted. If it does not exist it is initialised and then returned. Clients should store the handle returned by refernce or by pointer. Storage by value is highly discouraged.

It is only necessary to use the Open()/Close() API directly if you need access to the notification methods. Access to the static API does not require these to be used. Please remeber each call to Open() must have an equivalent Close().

Post-Condition

REComSession is connected and ready to issue ECOM requests.

Return value

REComSession & Reference to the open singleton session

Leave codes

... One of the system-wide error codes

IMPORT_C void Close();

Pre-Condition

REComSession must have been opened.

Description

Closes the open handle on the ECOM framework. Reference count is decremented and the ECOM client/server session is closed.

Post-Condition

REComSession reference count is decremented, server session closed

IMPORT_C void NotifyOnChange(TRequestStatus &aStatus);

Pre-Condition

REComSession must have been opened.

Description

Registers for notification messages when the underlying ECOM registration data changes. The client must not call this api again until their request is Completed as this could result in a 'stray signal'. This api should be placed first in the RunL of an Active Object otherwise changes could be lost. RunError should be implemented to cater for any Leaves. For example, it could retry after a second if the ECom server is busy rebuilding its indexes. CancelNotifyOnChange should be called to cancel this request and should NOT be part of the RunL.

Post-Condition

The caller is registered for receipt of notifications if the server's registry data changes.

Parameters

TRequestStatus &aStatus A request status object to complete for notification signalling.

IMPORT_C void CancelNotifyOnChange(TRequestStatus &aStatus);

Pre-Condition

REComSession must have been opened.

Description

De-registers for notification messages.

Post-Condition

The caller's registeration for reciept of notifications of registry data changes has been cancelled.

Parameters

TRequestStatus &aStatus The request status object originally passed to NotifyOnChange() for notification signalling.

static IMPORT_C void ListImplementationsL(TUid aInterfaceUid, RImplInfoPtrArray &aImplInfoArray);

Description

Retrieves a list of all the implementations which satisfy the specified interface. The aImplInfoArray on exit contains the plug-in implementations who's plug-in DLLs have sufficient capabilities to be loaded by the calling client process.

Post-Condition

REComSession has not changed, and aImplInfoArray contains the list of Implementation information for the interface.

Parameters

TUid aInterfaceUid A UID specifying the required interface. RImplInfoPtrArray &aImplInfoArray A reference to a client owned array which will be filled with interface implementation data. The array will first be cleared and all items destroyed before adding new data.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument

static IMPORT_C void ListImplementationsL(TUid aInterfaceUid, const TEComResolverParams &aResolutionParameters, RImplInfoPtrArray &aImplInfoArray);

Description

Retrieves a list of all the implementations which satisfy the specified interface with selection restriction to the specified parameters. The aImplInfoArray on exit contains the plug-in implementations who's plug-in DLLs have sufficient capabilities to be loaded by the calling client process.

Post-Condition

REComSession has not changed, and aImplInfoArray contains the list of Implementation information for the interface.

Parameters

TUid aInterfaceUid A UID specifying the required interface. const TEComResolverParams &aResolutionParameters Specifies any additional implementation characteristics to be fulfilled, maybe empty. RImplInfoPtrArray &aImplInfoArray A reference to a client owned array which will be filled with interface implementation data. The array will first be cleared and all items destroyed before adding new data.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument

See also:

• TEComResolverParams

static IMPORT_C void ListImplementationsL(TUid aInterfaceUid, const TEComResolverParams &aResolutionParameters, TUid aResolverUid, RImplInfoPtrArray &aImplInfoArray);

Description

Retrieves a list of all the implementations which satisfy the specified interface with selection restriction to the specified parameters. The aImplInfoArray on exit contains the plug-in implementations who's plug-in DLLs have sufficient capabilities to be loaded by the calling client process. Overload with a client provided CResolver.

Post-Condition

REComSession has not changed, and aImplInfoArray contains the list of Implementation information for the interface.

Parameters

TUid aInterfaceUid A UID specifying the required interface. const TEComResolverParams &aResolutionParameters Specifies any additional implementation characteristics to be fulfilled, maybe empty. TUid aResolverUid The CResolver UID which identifies the resolver implementation with the required client defined behaviour. RImplInfoPtrArray &aImplInfoArray A reference to a client owned array which will be filled with interface implementation data. The array will first be cleared and all items destroyed before adding new data.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied

See also:

• TEComResolverParams

static IMPORT_C TAny *CreateImplementationL(TUid aImplementationUid, TUid &aDtorIDKey);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aImplementationUid A UID specifying the required interface implementation. TUid &aDtorIDKey A 32 bit identifer returned by ECom to identify this instance to the framework.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

static IMPORT_C TAny *CreateImplementationL(TUid aImplementationUid, TInt32 aKeyOffset);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aImplementationUid A UID specifying the required interface implementation. TInt32 aKeyOffset An offset to the 32 bit identifer returned by the ECom framework to identify this instance to the framework.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

static IMPORT_C TAny *CreateImplementationL(TUid aImplementationUid, TUid &aDtorIDKey, TAny *aConstructionParameters);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aImplementationUid A UID specifying the required interface implementation. TUid &aDtorIDKey A 32 bit identifer returned by the ECom framework to identify this instance to the framework. TAny *aConstructionParameters The parameter structure to pass to the object creation method.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

static IMPORT_C TAny *CreateImplementationL(TUid aImplementationUid, TInt32 aKeyOffset, TAny *aConstructionParameters);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aImplementationUid A UID specifying the required interface implementation. TInt32 aKeyOffset An offset to the 32 bit identifer returned by the ECom framework to identify this instance to the framework. TAny *aConstructionParameters The parameter structure to pass to the object creation method.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

static IMPORT_C TAny *CreateImplementationL(TUid aInterfaceUid, TUid &aDtorIDKey, const TEComResolverParams &aResolutionParameters);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aInterfaceUid A UID specifying the required interface implementation. TUid &aDtorIDKey A 32 bit identifer returned by the ECom framework to identify this instance to the framework. const TEComResolverParams &aResolutionParameters Specifies any additional implementation characteristics to be fulfilled, maybe empty.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

See also:

• TEComResolverParams

static IMPORT_C TAny *CreateImplementationL(TUid aInterfaceUid, TInt32 aKeyOffset, const TEComResolverParams &aResolutionParameters);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aInterfaceUid A UID specifying the required interface implementation. TInt32 aKeyOffset An offset to the 32 bit identifer returned by the ECom framework to identify this instance to the framework. const TEComResolverParams &aResolutionParameters Specifies any additional implementation characteristics to be fulfilled, maybe empty.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

See also:

• TEComResolverParams

static IMPORT_C TAny *CreateImplementationL(TUid aInterfaceUid, TUid &aDtorIDKey, TAny *aConstructionParameters, const TEComResolverParams &aResolutionParameters);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aInterfaceUid A UID specifying the required interface implementation. TUid &aDtorIDKey A 32 bit identifer returned by the ECom framework to identify this instance to the framework. TAny *aConstructionParameters The parameter structure to pass to the object creation method. const TEComResolverParams &aResolutionParameters Specifies any additional implementation characteristics to be fulfilled, maybe empty. return TAny* A pointer to the instantiated interface implementation.

Return value

TAny *

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

See also:

• TEComResolverParams

static IMPORT_C TAny *CreateImplementationL(TUid aInterfaceUid, TInt32 aKeyOffset, TAny *aConstructionParameters, const TEComResolverParams &aResolutionParameters);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aInterfaceUid A UID specifying the required interface implementation. TInt32 aKeyOffset An offset to the 32 bit identifer returned by the ECom framework to identify this instance to the framework. TAny *aConstructionParameters The parameter structure to pass to the object creation method. const TEComResolverParams &aResolutionParameters Specifies any additional implementation characteristics to be fulfilled, maybe empty.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

See also:

• TEComResolverParams

static IMPORT_C TAny *CreateImplementationL(TUid aInterfaceUid, TUid &aDtorIDKey, const TEComResolverParams &aResolutionParameters, TUid aResolverUid);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aInterfaceUid A UID specifying the required interface implementation. TUid &aDtorIDKey A 32 bit identifer returned by the ECom framework to identify this instance to the framework. const TEComResolverParams &aResolutionParameters Specifies any additional implementation characteristics to be fulfilled, maybe empty. TUid aResolverUid The Uid of a CResolver with client defined behaviour.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

See also:

• TEComResolverParams

static IMPORT_C TAny *CreateImplementationL(TUid aInterfaceUid, TInt32 aKeyOffset, const TEComResolverParams &aResolutionParameters, TUid aResolverUid);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aInterfaceUid A UID specifying the required interface implementation. TInt32 aKeyOffset An offset to the 32 bit identifer returned by the ECom framework to identify this instance to the framework. const TEComResolverParams &aResolutionParameters Specifies any additional implementation characteristics to be fulfilled, maybe empty. TUid aResolverUid The Uid of a CResolver with client defined behaviour.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

See also:

• TEComResolverParams

static IMPORT_C TAny *CreateImplementationL(TUid aInterfaceUid, TUid &aDtorIDKey, TAny *aConstructionParameters, const TEComResolverParams &aResolutionParameters, TUid aResolverUid);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aInterfaceUid A UID specifying the required interface implementation. TUid &aDtorIDKey A 32 bit identifer returned by the ECom framework to identify this instance to the framework. TAny *aConstructionParameters The parameter structure to pass to the object creation method. const TEComResolverParams &aResolutionParameters Specifies any additional implementation characteristics to be fulfilled, maybe empty. TUid aResolverUid The Uid of a CResolver with client defined behaviour.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

See also:

• TEComResolverParams

static IMPORT_C TAny *CreateImplementationL(TUid aInterfaceUid, TInt32 aKeyOffset, TAny *aConstructionParameters, const TEComResolverParams &aResolutionParameters, TUid aResolverUid);

Description

Instantiates an interface implementation to satisfy the specified interface.

Post-Condition

The requested interface implementation is identified, and the instantiation method pointer is returned.

Parameters

TUid aInterfaceUid A UID specifying the required interface implementation. TInt32 aKeyOffset An offset to the 32 bit identifer returned by the ECom framework to identify this instance to the framework. TAny *aConstructionParameters The parameter structure to pass to the object creation method. const TEComResolverParams &aResolutionParameters Specifies any additional implementation characteristics to be fulfilled, maybe empty. TUid aResolverUid The Uid of a CResolver with client defined behaviour.

Return value

TAny * TAny* A pointer to the instantiated interface implementation.

Leave codes

KErrNoMemory KErrNotConnected KErrArgument KErrPermissionDenied. This leave error can happen under the following conditions: 1. There is a capability mismatch between the process creating the implementation and the DLL containing the implementation 2. The plugin DLL installed on the media card was not properly installed, either the system hash value of this plugin is missing or it is inconsistent with that calculated for the plugin DLL at load time.

See also:

• TEComResolverParams

static IMPORT_C void DestroyedImplementation(TUid aDtorIDKey);

Description

Signals the destruction of an interface implementation to ECOM. LoadManager is responsible for destroying the implementation

Post-Condition

The destruction of the Interface Implementation referred to by aDtorIDKey

Parameters

TUid aDtorIDKey A key specifying a previously created implementation.

static IMPORT_C void FinalClose();

Description

This method is used in processes that have utilised the ECOM framework, it does nothing if the ECOM framework has not been initialised. Its main purpose is to release memory and close handles held on unused plug-in implementations and their associated DLLs. If is found (through reference counting) that the ECOM framework is no longer in use in the calling thread the session to the ECOM's server is also closed.

This method is called by direct users of the ECOM framework wherever possible (e.g. library, server or test code). It is safe to call it at any time outside of plug-in code as the user's scenario dictates. This maybe during a test case or just before process termination.

Note: It must never be called from within a plug-in implementations class destructor, especially following a DestroyImplementation() as there is a risk that the plug-in's supporting DLL may immediately be unloaded by the Kernel due to the closure of RLibrary handles. It can result in a KERN-EXEC if the destructor call stack is still inside the DLL that is unloaded.

Note: Processes that utilise the ECOM framework that do not use this call are at risk of a UHEAP_MARKEND generated panic in debug builds.