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

/*
Copyright (c) 2000-2010 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
* Neither the name of Nokia Corporation nor the names of its contributors
  may be used to endorse or promote products derived from this software
  without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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);
        }

---