Source/WebCore/rendering/RenderIFrame.cpp

/*
 * Copyright (C) 2010 Apple Inc. All rights reserved.
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 * 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
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 *    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,
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#include "config.h"
#include "RenderIFrame.h"

#include "Frame.h"
#include "FrameView.h"
#include "HTMLIFrameElement.h"
#include "HTMLNames.h"
#include "Page.h"
#include "RenderView.h"
#include "Settings.h"

namespace WebCore {

using namespace HTMLNames;
    
RenderIFrame::RenderIFrame(Element* element)
    : RenderFrameBase(element)
{
}

bool RenderIFrame::shouldComputeSizeAsReplaced() const
{
    // When we're seamless, we use normal block/box sizing code except when inline.
    return !isSeamless();
}

bool RenderIFrame::isInlineBlockOrInlineTable() const
{
    return isSeamless() && isInline();
}

LayoutUnit RenderIFrame::minPreferredLogicalWidth() const
{
    if (!isSeamless())
        return RenderFrameBase::minPreferredLogicalWidth();

    RenderView* childRoot = contentRootRenderer();
    if (!childRoot)
        return 0;

    return childRoot->minPreferredLogicalWidth();
}

LayoutUnit RenderIFrame::maxPreferredLogicalWidth() const
{
    if (!isSeamless())
        return RenderFrameBase::maxPreferredLogicalWidth();

    RenderView* childRoot = contentRootRenderer();
    if (!childRoot)
        return 0;

    return childRoot->maxPreferredLogicalWidth();
}

bool RenderIFrame::isSeamless() const
{
    return node() && node()->hasTagName(iframeTag) && static_cast<HTMLIFrameElement*>(node())->shouldDisplaySeamlessly();
}

RenderView* RenderIFrame::contentRootRenderer() const
{
    // FIXME: Is this always a valid cast? What about plugins?
    ASSERT(!widget() || widget()->isFrameView());
    FrameView* childFrameView = static_cast<FrameView*>(widget());
    return childFrameView ? static_cast<RenderView*>(childFrameView->frame()->contentRenderer()) : 0;
}

bool RenderIFrame::flattenFrame() const
{
    if (!node() || !node()->hasTagName(iframeTag))
        return false;

    HTMLIFrameElement* element = static_cast<HTMLIFrameElement*>(node());
    Frame* frame = element->document()->frame();

    if (isSeamless())
        return false; // Seamless iframes are already "flat", don't try to flatten them.

    bool enabled = frame && frame->settings() && frame->settings()->frameFlatteningEnabled();

    if (!enabled || !frame->page())
        return false;

    if (style()->width().isFixed() && style()->height().isFixed()) {
        // Do not flatten iframes with scrolling="no".
        if (element->scrollingMode() == ScrollbarAlwaysOff)
            return false;
        if (style()->width().value() <= 0 || style()->height().value() <= 0)
            return false;
    }

    // Do not flatten offscreen inner frames during frame flattening, as flattening might make them visible.
    IntRect boundingRect = absoluteBoundingBoxRectIgnoringTransforms();
    return boundingRect.maxX() > 0 && boundingRect.maxY() > 0;
}

void RenderIFrame::layoutSeamlessly()
{
    updateLogicalWidth();
    // FIXME: Containers set their height to 0 before laying out their kids (as we're doing here)
    // however, this causes FrameView::layout() to add vertical scrollbars, incorrectly inflating
    // the resulting contentHeight(). We'll need to make FrameView::layout() smarter.
    setLogicalHeight(0);
    updateWidgetPosition(); // Tell the Widget about our new width/height (it will also layout the child document).

    // Laying out our kids is normally responsible for adjusting our height, so we set it here.
    // Replaced elements do not respect padding, so we just add border to the child's height.
    // FIXME: It's possible that seamless iframes (since they act like divs) *should* respect padding.
    FrameView* childFrameView = static_cast<FrameView*>(widget());
    if (childFrameView) // Widget should never be null during layout(), but just in case.
        setLogicalHeight(childFrameView->contentsHeight() + borderTop() + borderBottom());
    updateLogicalHeight();

    updateWidgetPosition(); // Notify the Widget of our final height.

    // Assert that the child document did a complete layout.
    RenderView* childRoot = childFrameView ? static_cast<RenderView*>(childFrameView->frame()->contentRenderer()) : 0;
    ASSERT(!childFrameView || !childFrameView->layoutPending());
    ASSERT_UNUSED(childRoot, !childRoot || !childRoot->needsLayout());
}

void RenderIFrame::layout()
{
    StackStats::LayoutCheckPoint layoutCheckPoint;
    ASSERT(needsLayout());

    if (isSeamless()) {
        layoutSeamlessly();
        // Do not return so as to share the layer and overflow updates below.
    } else {
        updateLogicalWidth();
        // No kids to layout as a replaced element.
        updateLogicalHeight();

        if (flattenFrame())
            layoutWithFlattening(style()->width().isFixed(), style()->height().isFixed());
    }

    m_overflow.clear();
    addVisualEffectOverflow();
    updateLayerTransform();

    setNeedsLayout(false);
}

}