Source/WebCore/rendering/RenderNamedFlowFragment.h

/*
 * Copyright (C) 2013 Adobe Systems Incorporated. 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 THE COPYRIGHT HOLDER "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 HOLDER BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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#ifndef RenderNamedFlowFragment_h
#define RenderNamedFlowFragment_h

#include "RenderRegion.h"

namespace WebCore {

class Element;
class RenderStyle;

// RenderNamedFlowFragment represents a region that is responsible for the fragmentation of
// the RenderNamedFlowThread content.
//
// A RenderNamedFlowFragment object is created as an anonymous child for a RenderBlockFlow object
// that has a valid -webkit-flow-from property.
//
// This allows a non-replaced block to behave like a region if needed, following the CSSRegions specification:
// http://dev.w3.org/csswg/css-regions/#the-flow-from-property.
// list-item, table-caption, table-cell can become regions in addition to block | inline-block.

class RenderNamedFlowFragment FINAL : public RenderRegion {
public:
    RenderNamedFlowFragment(Document&, PassRef<RenderStyle>);
    virtual ~RenderNamedFlowFragment();

    static PassRef<RenderStyle> createStyle(const RenderStyle& parentStyle);

    virtual bool isRenderNamedFlowFragment() const OVERRIDE FINAL { return true; }
    virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) OVERRIDE;

    virtual LayoutUnit maxPageLogicalHeight() const;

    bool isPseudoElementRegion() const { return parent() && parent()->isPseudoElement(); }

    // When the content inside the region requires the region to have a layer, the layer will be created on the region's
    // parent renderer instead.
    // This method returns that renderer holding the layer.
    // The return value may be null.
    RenderLayerModelObject* layerOwner() const { return parent() && parent()->isRenderLayerModelObject() ?
        toRenderLayerModelObject(parent()) : nullptr; }

    bool hasCustomRegionStyle() const { return m_hasCustomRegionStyle; }
    void setHasCustomRegionStyle(bool hasCustomRegionStyle) { m_hasCustomRegionStyle = hasCustomRegionStyle; }
    void clearObjectStyleInRegion(const RenderObject*);

    void setRegionObjectsRegionStyle();
    void restoreRegionObjectsOriginalStyle();

    RenderNamedFlowThread* namedFlowThread() const;

// FIXME: Temporarily public until we move all the CSSRegions functionality from RenderRegion to here.
public:
    void checkRegionStyle();

private:
    virtual bool shouldHaveAutoLogicalHeight() const OVERRIDE;
    virtual const char* renderName() const OVERRIDE { return "RenderNamedFlowFragment"; }

    PassRefPtr<RenderStyle> computeStyleInRegion(const RenderObject*);
    void computeChildrenStyleInRegion(const RenderElement*);
    void setObjectStyleInRegion(RenderObject*, PassRefPtr<RenderStyle>, bool objectRegionStyleCached);

    struct ObjectRegionStyleInfo {
        // Used to store the original style of the object in region
        // so that the original style is properly restored after paint.
        // Also used to store computed style of the object in region between
        // region paintings, so that the style in region is computed only
        // when necessary.
        RefPtr<RenderStyle> style;
        // True if the computed style in region is cached.
        bool cached;
    };

    typedef HashMap<const RenderObject*, ObjectRegionStyleInfo > RenderObjectRegionStyleMap;
    RenderObjectRegionStyleMap m_renderObjectRegionStyle;

    bool m_hasCustomRegionStyle : 1;
};

RENDER_OBJECT_TYPE_CASTS(RenderNamedFlowFragment, isRenderNamedFlowFragment())

} // namespace WebCore

#endif // RenderNamedFlowFragment_h