examples/Base/IPC/ClientServer/Gettingstarted/transient/src/client.cpp

// Copyright (c) 2000-2009 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:
// Transient server example - client interface implementation
//

#include <t-client.h>
#include "clientserver.h"

static TInt StartServer()
//
// Start the server process. Simultaneous launching
// of two such processes should be detected when the second one attempts to
// create the server object, failing with KErrAlreadyExists.
//
        {
        const TUidType serverUid(KNullUid,KNullUid,KServerUid3);
        RProcess server;
        TInt r=server.Create(KMyServerImg,KNullDesC,serverUid);
        if (r!=KErrNone)
                return r;
        TRequestStatus stat;
        server.Rendezvous(stat);
        if (stat!=KRequestPending)
                server.Kill(0);         // abort startup
        else
                server.Resume();        // logon OK - start the server
        User::WaitForRequest(stat);             // wait for start or death
        // we can't use the 'exit reason' if the server panicked as this
        // is the panic 'reason' and may be '0' which cannot be distinguished
        // from KErrNone
        r=(server.ExitType()==EExitPanic) ? KErrGeneral : stat.Int();
        server.Close();
        return r;
        }

EXPORT_C TInt RMySession::Connect()
//
// Connect to the server, attempting to start it if necessary
//
        {
        TInt retry=2;
        for (;;)
                {
                TInt r=CreateSession(KMyServerName,TVersion(0,0,0),1);
                if (r!=KErrNotFound && r!=KErrServerTerminated)
                        return r;
                if (--retry==0)
                        return r;
                r=StartServer();
                if (r!=KErrNone && r!=KErrAlreadyExists)
                        return r;
                }
        }

EXPORT_C TInt RMySession::Send(const TDesC& aMessage)
        {
        if (aMessage.Length()>KMaxMyMessage)
                return KErrArgument;
        return SendReceive(ESend,TIpcArgs(&aMessage));
        }

EXPORT_C void RMySession::Receive(TRequestStatus& aStatus,TDes& aMessage)
        {
        SendReceive(EReceive,TIpcArgs(&aMessage,aMessage.MaxLength()),aStatus);
        }

EXPORT_C void RMySession::CancelReceive()
        {
        SendReceive(ECancelReceive);
        }

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