Source/WebCore/bindings/js/JSTextTrackCueCustom.cpp

/*
 * Copyright (C) 2011 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 COMPUTER, 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
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 */

#include "config.h"

#if ENABLE(VIDEO_TRACK)

#include "JSTextTrackCue.h"
#include "JSTextTrackCustom.h"

using namespace JSC;

namespace WebCore {

bool JSTextTrackCueOwner::isReachableFromOpaqueRoots(JSC::Handle<JSC::Unknown> handle, void*, SlotVisitor& visitor)
{
    JSTextTrackCue* jsTextTrackCue = jsCast<JSTextTrackCue*>(handle.get().asCell());
    TextTrackCue* textTrackCue = static_cast<TextTrackCue*>(jsTextTrackCue->impl());

    // If the cue is firing event listeners, its wrapper is reachable because
    // the wrapper is responsible for marking those event listeners.
    if (textTrackCue->isFiringEventListeners())
        return true;

    // If the cue has no event listeners and has no custom properties, it is not reachable.
    if (!textTrackCue->hasEventListeners() && !jsTextTrackCue->hasCustomProperties())
        return false;

    // If the cue is not associated with a track, it is not reachable.
    if (!textTrackCue->track())
        return false;

    return visitor.containsOpaqueRoot(root(textTrackCue->track()));
}

void JSTextTrackCue::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
    JSTextTrackCue* jsTextTrackCue = jsCast<JSTextTrackCue*>(cell);
    ASSERT_GC_OBJECT_INHERITS(jsTextTrackCue, &s_info);
    COMPILE_ASSERT(StructureFlags & OverridesVisitChildren, OverridesVisitChildrenWithoutSettingFlag);
    ASSERT(jsTextTrackCue->structure()->typeInfo().overridesVisitChildren());
    Base::visitChildren(jsTextTrackCue, visitor);
    
    // Mark the cue's track root if it has one.
    TextTrackCue* textTrackCue = static_cast<TextTrackCue*>(jsTextTrackCue->impl());
    if (TextTrack* textTrack = textTrackCue->track())
        visitor.addOpaqueRoot(root(textTrack));
    
    textTrackCue->visitJSEventListeners(visitor);
}

} // namespace WebCore

#endif