examples/Base/IPC/AdvancedClientServerExample/ProcessClient/src/processclient.cpp

// Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
//


#include "processclient.h"
#include "processclientserver.h"
#include<e32debug.h>

#define KMaxServerNameLength 256

static const TUid KUidProcessServer = {0x10283037}; // Process Server UID
const TInt KCreateSessionRetryCount = 2;                                        //CreateSession retry count
const TInt KServerDefaultMessageSlots = 2;                      //server async Message Slots

static TInt StartServer()
        {
        const TUidType serverUid(KNullUid,KNullUid,KUidProcessServer);

        RProcess server;
        TInt r=server.Create(KProcessServerServerImg,KNullDesC,serverUid);
        if (r!=KErrNone)
                return r;
        TRequestStatus stat;
        server.Rendezvous(stat);

        if (stat!=KRequestPending)
                server.Kill(KErrCouldNotConnect);               // abort startup
        else
                server.Resume();        // logon OK - start the server
        
        User::WaitForRequest(stat);             // wait for start or death
        // The server exit type may be a panic value and a panic value can be zero, which is the same 
        // value as KErrNone. So, the exit type is tested for a panic before being returned.
        if (server.ExitType()==EExitPanic)
                {
                r = KErrServerTerminated;
                }
        else
                {
                r = stat.Int();
                }
        server.Close();
        return r;
        }
EXPORT_C TInt RProcessClient::Connect()
        {
        TInt retry=KCreateSessionRetryCount; //number of CreateSession retries
        FOREVER
                {
                // try to create a session with the server which has KServerDefaultMessageSlots async message slots.
                TInt r=CreateSession(KProcessServerName,
                                                         TVersion(KProcessServerVersion,
                                                                          KProcessServerMinorVersionNumber,
                                                                          KProcessServerBuildVersionNumber),
                                                         KServerDefaultMessageSlots);                                                    
                if (r!=KErrNotFound && r!=KErrServerTerminated)
                        return r;
                if (--retry==0)
                        return r;
                r=StartServer();        
                if (r!=KErrNone && r!=KErrAlreadyExists)
                        return r;
                // 1. r=KErrNone means server starts up successfully.
                // 2. r=KErrAlreadyExists means a duplicate server was trying to start up.
                //              Note: if there are other functions called before CServer2::StartL() during construction,
                //                other errors might happen when the duplicate server is trying to start.
                //            Therefore, we recommend CServer2::StartL() is the first function in server construction
                //            @see CProcessServer::ConstructL()
                //
                // NOTE: If users would like to retry start up server after other scenarios happened, e.g. panic,then go 
                //               through the following steps:
                //                1. Increase the value of KCreateSessionRetryCount (only start up server once in this example)
                //                2. Need another variable, e.g. TExitType, together with error code returned in StartServer()
                //                      to distinguish these scenarios
                //                3. Modify the third if statement to stop exit when the required scenarios happens.
                //           
                }
        }
EXPORT_C TInt RProcessClient::OpenDriver()
        {
        return SendReceive(EOpenDriver);
        }
EXPORT_C void RProcessClient::Send(const TDesC8& aBuf, TRequestStatus& aStatus)
        {
        SendReceive(EDummyLDDSendData, TIpcArgs(&aBuf), aStatus);
        }
EXPORT_C void RProcessClient::SendCancel()
        {
        SendReceive(EDummyLDDSendDataCancel);
        }
EXPORT_C TInt RProcessClient::UnloadDeviceDriver()
        {
        return SendReceive(EUnloadDeviceDriver);
        }
EXPORT_C TInt RProcessClient::LoadDeviceDriver()
        {
        return SendReceive(ELoadDeviceDriver);
        }

//EOF

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