/*

 * Copyright (C) 2010 Google Inc. 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 Google Inc. 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

 * OWNER 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,

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 */

#ifndef DragScrollTimer_h

#define DragScrollTimer_h

#include "IntSize.h"

#include "Timer.h"

#include "WebPoint.h"

namespace WebCore { class FrameView; }

namespace WebKit {

//

// Encapsulating a timer and associated state management for

// scroll-on-drag behaviour.

//

class DragScrollTimer {

public:

    DragScrollTimer();

    ~DragScrollTimer();

    void fired(WebCore::Timer<DragScrollTimer>*) { update(); }

    void triggerScroll(WebCore::FrameView*, const WebPoint&);

    void stop();

private:

    void scroll();

    void update();

    WebCore::IntSize scrollDistanceFor(WebCore::FrameView*, const WebPoint&) const;

    bool shouldScroll() const { return !m_lastDistance.isZero(); }

    WebCore::Timer<DragScrollTimer> m_timer;

    WebCore::FrameView* m_view;

    WebCore::IntSize m_lastDistance;

    bool m_scrolling;

};

} // namespace WebKit

#endif