--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/usbuis/usbui/USBClassChangeUIPlugin/inc/USBDeviceStateWatcher.h	Wed Sep 01 12:20:49 2010 +0100
@@ -0,0 +1,158 @@
+/*
+* Copyright (c) 2007 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:  Device state watcher class.
+ *
+*/
+
+
+#ifndef USBDEVICESTATEWATCHER_H
+#define USBDEVICESTATEWATCHER_H
+
+// INCLUDE FILES
+#include <e32base.h>
+#include <usbman.h>
+
+/**
+ * A callback interface for informing about device state changes
+ */
+class MUSBDeviceStateObserver
+    {
+    public:
+        
+        /**
+         * Informs the observer that USB device state has changed.
+         * @param aPreviousState previous device state.
+         * @param aCurrentState current device state.
+         */
+        virtual void DeviceStateChanged(TUsbDeviceState aPreviousState,
+                                        TUsbDeviceState aCurrentState) = 0;
+    };
+
+// CLASS DECLARATION
+
+/**
+ * Class that listens for USB device state changes and notifies
+ * the observer.
+ */
+class CUSBDeviceStateWatcher : public CActive
+    {
+    public:  // Constructors and destructor
+        
+        /**
+         * Two-phased constructor. Uses existing usb manager session.
+         * Note that it's not possible (and usually not necessary) to attach
+         * more than one USBDeviceStateWatcher to the same session.
+         *
+         * @param aObserver  Reference to device state observer.
+         * @param aUsbMan    Existing usb manager session.
+         * @return Pointer to created object.
+         */
+        static CUSBDeviceStateWatcher* NewL(MUSBDeviceStateObserver& aObserver,
+            RUsb& aUsbMan);
+        
+        /**
+         * Two-phased constructor. Creates its own usb manager session.
+         *
+         * @param aObserver  Reference to device state observer.
+         * @return Pointer to created object.
+         */
+        static CUSBDeviceStateWatcher* NewL(MUSBDeviceStateObserver& aObserver);
+        
+        /**
+        * Destructor.
+        */
+        virtual ~CUSBDeviceStateWatcher();
+
+    public: // from base class CActive
+
+        /**
+        * From CActive.
+        * This method is called when device state has changed.
+        */
+        void RunL();
+
+        /**
+        * From CActive.
+        * In this implementation this method should never be called.
+        *
+        * @param aError the leave code
+        * @return KErrNone
+        */
+        TInt RunError(TInt aError);
+
+        /**
+        * From CActive
+        * If there is outstanding request pending when Cancel() is called then
+        * this method must cancel request.
+        */
+        void DoCancel();
+
+    private:
+
+        /**
+         * Private constructor.
+         *
+         * @param aObserver Reference to MUSBDeviceStateObserver.
+         */
+        CUSBDeviceStateWatcher(MUSBDeviceStateObserver& aObserver);
+
+        /**
+         * 2nd phase constructor.
+         * Creates its own usb manager session.
+         */
+        void ConstructL();
+        
+        /**
+         * 2nd phase constructor.
+         * Uses existing usb manager session.
+         *
+         * @param aUsbMan    Existing usb manager session.
+         */
+        void ConstructL(RUsb& aUsbMan);
+        
+        /**
+         * Code shared by all ConstructL methods.
+         */
+        void CommonConstructL();
+        
+        // Disable default C++ behavior that makes no sense
+        // for this implementation.
+        CUSBDeviceStateWatcher();
+        CUSBDeviceStateWatcher(const CUSBDeviceStateWatcher&);
+        CUSBDeviceStateWatcher& operator=(const CUSBDeviceStateWatcher&);
+
+    private: // Data
+
+        /**
+         * Handle to Usb Manager
+         */
+        RUsb iUsbMan;
+
+        /**
+         * Current device state
+         */
+        TUsbDeviceState iCurrentState;
+
+        /**
+         * Last known device state
+         */
+        TUsbDeviceState iPreviousState;
+
+        /**
+         * Refernce to the observer
+         */
+        MUSBDeviceStateObserver& iObserver;
+    };
+
+#endif   // USBDEVICESTATEWATCHER_H