examples/Base/IPC/pubsub/subscribespec.cpp

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/*
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Description: Demonstrates the speculative pattern of subscribing to a byte-array property  
*/



#include "subscribe.h"
LOCAL_D CConsoleBase* console;

CArrayPropertyWatch::CArrayPropertyWatch():CActive(EPriority)
        {
        }

void CArrayPropertyWatch::ConstructL(CConsoleBase* aConsole)
        {
        User::LeaveIfError(iProperty.Attach(KMyPropertyCat,KMyPropertyName));
        iConsole = aConsole;
        CActiveScheduler::Add(this);
        }

CArrayPropertyWatch* CArrayPropertyWatch::NewL(CConsoleBase* aConsole)
        {
        CArrayPropertyWatch* self = new (ELeave) CArrayPropertyWatch;
        CleanupStack::PushL(self);
        self->ConstructL(aConsole);
        CleanupStack::Pop(self);
        return self;
        }

CArrayPropertyWatch::~CArrayPropertyWatch()
        {
        iProperty.Close();
        // Delete the property as it is no longer required by the subscriber
        RProperty::Delete(KMyPropertyCat, KMyPropertyName);
        Cancel();
        }

void CArrayPropertyWatch::DoCancel()
        {
        iProperty.Cancel();
        }

void CArrayPropertyWatch::RunL()
        {
        // Get the value of the property
        TBuf16<KArraySize> buf;
        TInt err = iProperty.Get(buf);
        if(err == KErrNotFound)
                {
                // Leave the function if the property is not defined
                CActiveScheduler::Stop();
                User::Leave(err);
                }
        else
                {
                // Print the value of the property
                PrintProperty(buf);
                if(buf == KStop)
                        {
                        CActiveScheduler::Stop();
                        }
                else
                        {
                        // Re-subscribe to the property
                        iProperty.Subscribe(iStatus);
                        SetActive();
                        }
                }
        }

void CArrayPropertyWatch::PrintProperty(TDes16& aBuf)
        {
        iConsole->Printf(KTxtArray);
        TInt bufLength = aBuf.Length();
        for(TInt ix = 0; ix < bufLength;ix++)
                {
                iConsole->Printf(KTxtArrayElement,aBuf[ix]);
                }
        iConsole->Printf(KTxtNewLine);
        }

void CArrayPropertyWatch::DefinePropertyL()
        {
        iConsole->Printf(KTxtDefine);
        // Define the property
        TInt err = RProperty::Define(KMyPropertyCat, KMyPropertyName,RProperty::EByteArray,KAllowAllPolicy,KAllowAllPolicy,KArraySize);
        if(err == KErrAlreadyExists || err == KErrNone)
                {
                // Ignore the KErrAlreadyExists error code
                TBuf16<KArraySize> buf;
                // Returns the default value of the property
                // Ignore this value
                err = iProperty.Get(buf);
                User::LeaveIfError(err);
                // Subscribe to the property and maintain an outstanding request
                iProperty.Subscribe(iStatus);
                SetActive();
                }
        else
                {
                // Leave in case of errors other than KErrAlreadyExists
                User::Leave(err);
                }
        }

void DoExampleL()
        {
        CActiveScheduler* scheduler = new (ELeave) CActiveScheduler();
        CleanupStack::PushL(scheduler);
        CActiveScheduler::Install(scheduler);

        console->Printf(KTxtSpecSub);

        // Create the byte-array property watch active object
        CArrayPropertyWatch* obj = CArrayPropertyWatch::NewL(console);
        CleanupStack::PushL(obj);

        // Subscribe to the property and start the scheduler
        obj->DefinePropertyL();
        CActiveScheduler::Start();

        CleanupStack::PopAndDestroy(obj);
        CleanupStack::PopAndDestroy(scheduler);
        }

GLDEF_C TInt E32Main()
        {
        __UHEAP_MARK;
        CTrapCleanup* cleanup = CTrapCleanup::New();

        TRAPD(createError, console = Console::NewL(KTextConsoleTitle, TSize(KConsFullScreen,KConsFullScreen)));
        if (createError)
                return createError;

        TRAPD(mainError, DoExampleL());
        if (mainError)
                console->Printf(KTextFailed, mainError);
        console->Printf(KTextPressAnyKey);
        console->Getch();

        delete console;
        delete cleanup;
        __UHEAP_MARKEND;
        return KErrNone;
        }

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