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

/*
Copyright (c) 2007-2010 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:  
*/



#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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