Source/WebCore/layout/layouttree/LayoutBox.h

/*
 * Copyright (C) 2018 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. AND ITS CONTRIBUTORS ``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 INC. OR ITS 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.
 */

#pragma once

#if ENABLE(LAYOUT_FORMATTING_CONTEXT)

#include "RenderStyle.h"
#include <wtf/IsoMalloc.h>
#include <wtf/WeakPtr.h>

namespace WebCore {

namespace Layout {

class Container;
class TreeBuilder;

class Box {
    WTF_MAKE_ISO_ALLOCATED(Box);
public:
    friend class TreeBuilder;

    virtual ~Box();

    bool establishesFormattingContext() const;
    virtual bool establishesBlockFormattingContext() const;
    virtual bool establishesInlineFormattingContext() const { return false; }

    bool isInFlow() const { return !isFloatingOrOutOfFlowPositioned(); }
    bool isPositioned() const { return isInFlowPositioned() || isOutOfFlowPositioned(); }
    bool isInFlowPositioned() const { return isRelativelyPositioned() || isStickyPositioned(); }
    bool isOutOfFlowPositioned() const { return isAbsolutelyPositioned() || isFixedPositioned(); }
    bool isRelativelyPositioned() const;
    bool isStickyPositioned() const;
    bool isAbsolutelyPositioned() const;
    bool isFixedPositioned() const;
    bool isFloatingPositioned() const;

    bool isFloatingOrOutOfFlowPositioned() const { return isFloatingPositioned() || isOutOfFlowPositioned(); }

    const Container* containingBlock() const;
    const Container& formattingContextRoot() const;
    bool isDescendantOf(Container&) const;

    bool isAnonymous() const { return m_isAnonymous; }

    bool isBlockLevelBox() const;
    bool isInlineLevelBox() const;
    bool isInlineBlockBox() const;
    bool isBlockContainerBox() const;
    bool isInitialContainingBlock() const;

    const Container* parent() const { return m_parent; }
    const Box* nextSibling() const { return m_nextSibling; }
    const Box* nextInFlowSibling() const;
    const Box* nextInFlowOrFloatingSibling() const;
    const Box* previousSibling() const { return m_previousSibling; }
    const Box* previousInFlowSibling() const;
    const Box* previousInFlowOrFloatingSibling() const;

    typedef unsigned BaseTypeFlags;
    bool isContainer() const { return m_baseTypeFlags & ContainerFlag; }
    bool isBlockContainer() const { return m_baseTypeFlags & BlockContainerFlag; }
    bool isInlineBox() const { return m_baseTypeFlags & InlineBoxFlag; }
    bool isInlineContainer() const { return m_baseTypeFlags & InlineContainerFlag; }

    const RenderStyle& style() const { return m_style; }
    auto& weakPtrFactory() const { return m_weakFactory; }

protected:
    enum BaseTypeFlag {
        ContainerFlag         = 1 << 0,
        BlockContainerFlag    = 1 << 1,
        InlineBoxFlag         = 1 << 2,
        InlineContainerFlag   = 1 << 3
    };
    Box(RenderStyle&&, BaseTypeFlags);

    bool isOverflowVisible() const;

private:
    void setParent(Container& parent) { m_parent = &parent; }
    void setNextSibling(Box& nextSibling) { m_nextSibling = &nextSibling; }
    void setPreviousSibling(Box& previousSibling) { m_previousSibling = &previousSibling; }
    void setIsAnonymous() { m_isAnonymous = true; }

    WeakPtrFactory<Box> m_weakFactory;
    RenderStyle m_style;

    Container* m_parent { nullptr };
    Box* m_previousSibling { nullptr };
    Box* m_nextSibling { nullptr };

    unsigned m_baseTypeFlags : 4;
    unsigned m_isAnonymous : 1;

};

}
}

#define SPECIALIZE_TYPE_TRAITS_LAYOUT_BOX(ToValueTypeName, predicate) \
SPECIALIZE_TYPE_TRAITS_BEGIN(WebCore::Layout::ToValueTypeName) \
    static bool isType(const WebCore::Layout::Box& box) { return box.predicate; } \
SPECIALIZE_TYPE_TRAITS_END()

#endif