Add MediaPlayer support to AVFoundation plugin

This plugin would be used on Mac 10.7+ where without the QuickTime C API
our QT7 media player performance was crippled.

Change-Id: Iaadb1990a8f63393c4cd02d096624e0fed42b40f
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Jason Barron <jason.barron@digia.com>
Reviewed-by: Andy Nichols <andy.nichols@digia.com>

src/plugins/avfoundation/mediaplayer/avfdisplaylink.mm

@@ -0,0 +1,159 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "avfdisplaylink.h"
+#include <QtCore/qcoreapplication.h>
+
+#ifdef QT_DEBUG_AVF
+#include <QtCore/qdebug.h>
+#endif
+
+QT_USE_NAMESPACE
+
+static CVReturn CVDisplayLinkCallback(CVDisplayLinkRef displayLink,
+                                 const CVTimeStamp *inNow,
+                                 const CVTimeStamp *inOutputTime,
+                                 CVOptionFlags flagsIn,
+                                 CVOptionFlags *flagsOut,
+                                 void *displayLinkContext)
+{
+    Q_UNUSED(displayLink);
+    Q_UNUSED(inNow);
+    Q_UNUSED(flagsIn);
+    Q_UNUSED(flagsOut);
+
+    AVFDisplayLink *link = (AVFDisplayLink *)displayLinkContext;
+
+    link->displayLinkEvent(inOutputTime);
+    return kCVReturnSuccess;
+}
+
+AVFDisplayLink::AVFDisplayLink(QObject *parent)
+    : QObject(parent)
+    , m_pendingDisplayLinkEvent(false)
+    , m_isActive(false)
+{
+    // create display link for the main display
+    CVDisplayLinkCreateWithCGDisplay(kCGDirectMainDisplay, &m_displayLink);
+    if (m_displayLink) {
+        // set the current display of a display link.
+        CVDisplayLinkSetCurrentCGDisplay(m_displayLink, kCGDirectMainDisplay);
+
+        // set the renderer output callback function
+        CVDisplayLinkSetOutputCallback(m_displayLink, &CVDisplayLinkCallback, this);
+    }
+}
+
+AVFDisplayLink::~AVFDisplayLink()
+{
+#ifdef QT_DEBUG_AVF
+    qDebug() << Q_FUNC_INFO;
+#endif
+
+    if (m_displayLink) {
+        CVDisplayLinkStop(m_displayLink);
+        CVDisplayLinkRelease(m_displayLink);
+        m_displayLink = NULL;
+    }
+}
+
+bool AVFDisplayLink::isValid() const
+{
+    return m_displayLink != 0;
+}
+
+bool AVFDisplayLink::isActive() const
+{
+    return m_isActive;
+}
+
+void AVFDisplayLink::start()
+{
+    if (m_displayLink && !m_isActive) {
+       CVDisplayLinkStart(m_displayLink);
+       m_isActive = true;
+    }
+}
+
+void AVFDisplayLink::stop()
+{
+    if (m_displayLink && m_isActive) {
+        CVDisplayLinkStop(m_displayLink);
+        m_isActive = false;
+    }
+}
+
+
+void AVFDisplayLink::displayLinkEvent(const CVTimeStamp *ts)
+{
+    // This function is called from a
+    // thread != gui thread. So we post the event.
+    // But we need to make sure that we don't post faster
+    // than the event loop can eat:
+    m_displayLinkMutex.lock();
+    bool pending = m_pendingDisplayLinkEvent;
+    m_pendingDisplayLinkEvent = true;
+    m_frameTimeStamp = *ts;
+    m_displayLinkMutex.unlock();
+
+    if (!pending)
+        qApp->postEvent(this, new QEvent(QEvent::User), Qt::HighEventPriority);
+}
+
+bool AVFDisplayLink::event(QEvent *event)
+{
+    switch (event->type()){
+        case QEvent::User:  {
+                m_displayLinkMutex.lock();
+                m_pendingDisplayLinkEvent = false;
+                CVTimeStamp ts = m_frameTimeStamp;
+                m_displayLinkMutex.unlock();
+
+                Q_EMIT tick(ts);
+
+                return false;
+            }
+            break;
+        default:
+            break;
+    }
+    return QObject::event(event);
+}