dnsresolverengine.cpp

《基于Symbian OS的手机开发与应用实践》这本书的配套源码。

/*
* ============================================================================
*  Name     : CDnsResolverEngine from DnsResolverEngine.cpp
*  Part of  : UdpSocket
*  Created  : 31.01.2006 by ToBeReplacedByAuthor
*  Implementation notes:
*  
*  Version  :
*  Copyright: ToBeReplacedByCopyright
* ============================================================================
*/

// INCLUDE FILES
#include "DnsResolverEngine.h"

// CONSTANTS
const TInt KTimeout = 10; // seocnds

// ================= MEMBER FUNCTIONS =======================

// Two-phased constructor.
CDnsResolverEngine* CDnsResolverEngine::NewL(MObserver& aObserver)
    {
    CDnsResolverEngine* self = new (ELeave) CDnsResolverEngine( aObserver );
    CleanupStack::PushL( self );
    self->ConstructL();
    CleanupStack::Pop();
    return self;
    }

// destructor
CDnsResolverEngine::~CDnsResolverEngine()
    {
    Cancel();
    delete iTimer;
    iHostResolver.Close();
    iSocketServ.Close();
    }

void CDnsResolverEngine::GetHostName()
    {
    Cancel();
    iTimer->Start(KTimeout);
    iState = EStateGettingHostName;
    iHostResolver.GetHostName(iHostName, iStatus);
    SetActive();
    }

// New functions
void CDnsResolverEngine::GetByName(const THostName& aHostName)
    {
    Cancel();
    iTimer->Start(KTimeout);
    iState = EStateGettingByName;
    iHostName.Copy(aHostName);
    iHostResolver.GetByName(iHostName, iNameEntry, iStatus);
    SetActive();
    }

void CDnsResolverEngine::GetByAddressL(const TDesC& aAddr)
    {
    Cancel();
    iTimer->Start(KTimeout);
    iState = EStateGettingByAddress;
    User::LeaveIfError(iInetAddr.Input(aAddr));
    iHostResolver.GetByAddress(iInetAddr, iNameEntry, iStatus);
    SetActive();
    }

// Functions from CDnsResolverTimer::MObserver
void CDnsResolverEngine::OnTimerL(TInt aError)
    {
    Cancel();
    TInt err = (aError==KErrNone)? KErrTimedOut:aError;
    iObserver.OnResolvedL(KNullDesC(), err);
    }

// Functions from CActive
void CDnsResolverEngine::DoCancel()
    {
    if(iTimer!=NULL)
        {
        iTimer->Cancel();
        }
    iState = EStateIdle;
    iHostResolver.Cancel();
    }

void CDnsResolverEngine::RunL()
    {
    iTimer->Cancel();
    TInt err = iStatus.Int();
    switch(iState)
        {
        case EStateGettingHostName:
            {
            iObserver.OnResolvedL(iHostName, err);
            break;
            }
        case EStateGettingByName:
            {
            if(err==KErrNone)
                {
                TNameRecord& nr = iNameEntry();
                iInetAddr.Copy(nr.iAddr);
                TBuf<15> ip;
                iInetAddr.Output(ip);
                iObserver.OnResolvedL(ip, err);
                }
            else
                {
                iObserver.OnResolvedL(KNullDesC(), err);
                }
            break;
            }
        case EStateGettingByAddress:
            {
            if(err==KErrNone)
                {
                TNameRecord& nr = iNameEntry();
                iObserver.OnResolvedL(nr.iName, err);
                }
            else
                {
                iObserver.OnResolvedL(KNullDesC(), err);
                }
            break;
            }
        default:
            {
            // should be unreachable
            }
        }
    iState = EStateIdle;
    }

// constructor
CDnsResolverEngine::CDnsResolverEngine(MObserver& aObserver)
: CActive(CActive::EPriorityStandard), iObserver(aObserver)
    {
    CActiveScheduler::Add(this);
    }

// EPOC default constructor can leave.
void CDnsResolverEngine::ConstructL()
    {
    // Open a session to Socket Server
    User::LeaveIfError(iSocketServ.Connect());

    // Open a host resolver
    User::LeaveIfError(iHostResolver.Open(iSocketServ, KAfInet, KProtocolInetUdp));

    // Create a timeout timer
    iTimer = CDnsResolverTimer::NewL(*this);
    }

// End of File