Function LocalProcessMessage

Core/ConnectionSML/src/sml_EmbeddedConnection.cpp:84–141

* @brief This is the raw function which will be called by the other * side of the embeddded connection to pass a message. * In some sense, all message passing starts here. * * The parameters are defined as "handles". That it, they are opaque * pointers. * * The connection handle is our "EmbeddedConnection" object * which we pass to the other side of the embedded con

*
*************************************************************/
ElementXML_Handle LocalProcessMessage(Connection_Receiver_Handle hReceiverConnection, ElementXML_Handle hIncomingMsg, int action)
{
    // This is the connection object we created in this class, passed to the kernel and have
    // now received back.
    EmbeddedConnection* pConnection = reinterpret_cast<EmbeddedConnection*>(hReceiverConnection) ;
    
    // Make sure we have been passed a valid connection object.
    if (pConnection == NULL)
    {
        return NULL ;
    }
    
    if (action == SML_MESSAGE_ACTION_CLOSE)
    {
        // Close our connection to the remote process
        pConnection->ClearConnectionHandle() ;
        
        return NULL ;
    }
    
    // Synch connections are all happening within a single thread
    if (action == SML_MESSAGE_ACTION_SYNCH)
    {
        // Create an object to wrap this message.
        ElementXML incomingMsg(hIncomingMsg) ;
        
        // For a synchronous connection, immediately execute the incoming message, generating a response
        // which is immediately passed back to the caller.
        ElementXML* pResponse = pConnection->InvokeCallbacks(&incomingMsg) ;
        
        if (!pResponse)
        {
            return NULL ;
        }
        
        ElementXML_Handle hResponse = pResponse->Detach() ;
        delete pResponse ;
        return hResponse ;
    }
    
    // Asynch connections involve a thread switch.  The message comes in on
    // one thread, is dropped in a message queue and picked up by a second thread.
    if (action == SML_MESSAGE_ACTION_ASYNCH)
    {
        // Store the incoming message on a queue and execute it on the receiver's thread (our thread) at a later point.
        EmbeddedConnectionAsynch* eca = static_cast<EmbeddedConnectionAsynch*>(pConnection);
        eca->AddToIncomingMessageQueue(hIncomingMsg) ;
        
        // There is no immediate response to an asynch message.
        // The response will be sent back to the caller as another asynch message later, once the command has been executed.
        return NULL ;
    }
    
    // Not an action we understand, so just ignore it.
    // This allows future versions to use other actions if they wish and
    // we'll remain somewhat compatible.
    return NULL ;
}