Source/WebCore/platform/graphics/DisplayRefreshMonitor.h

/*
 * Copyright (C) 2010 Apple 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:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE COMPUTER, INC. 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. 
 */

#ifndef DisplayRefreshMonitor_h
#define DisplayRefreshMonitor_h

#if USE(REQUEST_ANIMATION_FRAME_DISPLAY_MONITOR)

#include "PlatformScreen.h"
#include <wtf/HashMap.h>
#include <wtf/HashSet.h>
#include <wtf/RefCounted.h>
#include <wtf/RefPtr.h>
#include <wtf/Threading.h>
#if PLATFORM(BLACKBERRY)
#include <BlackBerryPlatformAnimationFrameRateController.h>
#endif

#if PLATFORM(MAC)
typedef struct __CVDisplayLink *CVDisplayLinkRef;
#endif

namespace WebCore {

class DisplayRefreshMonitor;
class DisplayRefreshMonitorManager;

//
// Abstract virtual client which receives refresh fired messages on the main thread
//
class DisplayRefreshMonitorClient {
    friend class DisplayRefreshMonitor;
    friend class DisplayRefreshMonitorManager;
    
public:
    DisplayRefreshMonitorClient();
    virtual ~DisplayRefreshMonitorClient();
    
    virtual void displayRefreshFired(double timestamp) = 0;

private:
    void fireDisplayRefreshIfNeeded(double timestamp);
    
    void setDisplayID(PlatformDisplayID displayID)
    {
        m_displayID = displayID;
        m_displayIDIsSet = true;
    }
    
    bool m_scheduled;
    bool m_displayIDIsSet;
    PlatformDisplayID m_displayID;
};

#if PLATFORM(BLACKBERRY)
class DisplayAnimationClient : public BlackBerry::Platform::AnimationFrameRateClient {
public:
    DisplayAnimationClient(DisplayRefreshMonitor *);
    ~DisplayAnimationClient() { }
private:
    virtual void animationFrameChanged();
    DisplayRefreshMonitor *m_monitor;
};
#endif

//
// Monitor for display refresh messages for a given screen
//

class DisplayRefreshMonitor : public RefCounted<DisplayRefreshMonitor> {
public:
    static PassRefPtr<DisplayRefreshMonitor> create(PlatformDisplayID displayID)
    {
        return adoptRef(new DisplayRefreshMonitor(displayID));
    }
    
    ~DisplayRefreshMonitor();
    
    // Return true if callback request was scheduled, false if it couldn't be
    // (e.g., hardware refresh is not available)
    bool requestRefreshCallback();
    void windowScreenDidChange(PlatformDisplayID);
    
    bool hasClients() const { return m_clients.size(); }
    void addClient(DisplayRefreshMonitorClient*);
    bool removeClient(DisplayRefreshMonitorClient*);
    
    PlatformDisplayID displayID() const { return m_displayID; }

    bool shouldBeTerminated() const
    {
        const int maxInactiveFireCount = 10;
        return !m_scheduled && m_unscheduledFireCount > maxInactiveFireCount;
    }
    
private:
    DisplayRefreshMonitor(PlatformDisplayID);

    void displayDidRefresh();
    static void handleDisplayRefreshedNotificationOnMainThread(void* data);

    double m_monotonicAnimationStartTime;
    bool m_active;
    bool m_scheduled;
    bool m_previousFrameDone;
    int m_unscheduledFireCount; // Number of times the display link has fired with no clients.
    PlatformDisplayID m_displayID;
    Mutex m_mutex;
    
    typedef HashSet<DisplayRefreshMonitorClient*> DisplayRefreshMonitorClientSet;
    DisplayRefreshMonitorClientSet m_clients;
#if PLATFORM(BLACKBERRY)
public:
    void displayLinkFired();
private:
    DisplayAnimationClient *m_animationClient;
    void startAnimationClient();
    void stopAnimationClient();
#endif
#if PLATFORM(MAC)
public:
    void displayLinkFired(double nowSeconds, double outputTimeSeconds);
private:
    CVDisplayLinkRef m_displayLink;
#endif
};

//
// Singleton manager for all the DisplayRefreshMonitors. This is the interface to the 
// outside world. It distributes requests to the appropriate monitor. When the display
// refresh event fires, the passed DisplayRefreshMonitorClient is called directly on
// the main thread.
//
class DisplayRefreshMonitorManager {
public:
    static DisplayRefreshMonitorManager* sharedManager();
    
    void registerClient(DisplayRefreshMonitorClient*);
    void unregisterClient(DisplayRefreshMonitorClient*);

    bool scheduleAnimation(DisplayRefreshMonitorClient*);
    void windowScreenDidChange(PlatformDisplayID, DisplayRefreshMonitorClient*);

private:
    friend class DisplayRefreshMonitor;
    void displayDidRefresh(DisplayRefreshMonitor*);
    
    DisplayRefreshMonitorManager() { }
    DisplayRefreshMonitor* ensureMonitorForClient(DisplayRefreshMonitorClient*);

    // We know nothing about the values of PlatformDisplayIDs, so use UnsignedWithZeroKeyHashTraits.
    typedef HashMap<uint64_t, RefPtr<DisplayRefreshMonitor>, WTF::IntHash<uint64_t>, WTF::UnsignedWithZeroKeyHashTraits<uint64_t> > DisplayRefreshMonitorMap;
    DisplayRefreshMonitorMap m_monitors;
};

}

#endif // USE(REQUEST_ANIMATION_FRAME_DISPLAY_MONITOR)

#endif