RenderStyle.cpp

/*
 * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
 * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"
#include "RenderStyle.h"

#include "ContentData.h"
#include "CursorList.h"
#include "CSSPropertyNames.h"
#include "Font.h"
#include "FontSelector.h"
#include "Pagination.h"
#include "QuotesData.h"
#include "RenderObject.h"
#include "ScaleTransformOperation.h"
#include "ShadowData.h"
#include "StyleImage.h"
#include "StyleInheritedData.h"
#include "StyleResolver.h"
#if ENABLE(TOUCH_EVENTS)
#include "RenderTheme.h"
#endif
#include <wtf/MathExtras.h>
#include <wtf/StdLibExtras.h>
#include <algorithm>

#if ENABLE(IOS_TEXT_AUTOSIZING)
#include <wtf/text/StringHash.h>
#endif

#if ENABLE(TEXT_AUTOSIZING)
#include "TextAutosizer.h"
#endif

namespace WebCore {

struct SameSizeAsBorderValue {
    RGBA32 m_color;
    unsigned m_width;
};

COMPILE_ASSERT(sizeof(BorderValue) == sizeof(SameSizeAsBorderValue), BorderValue_should_not_grow);

struct SameSizeAsRenderStyle : public RefCounted<SameSizeAsRenderStyle> {
    void* dataRefs[7];
    void* ownPtrs[1];
#if ENABLE(SVG)
    void* dataRefSvgStyle;
#endif
    struct InheritedFlags {
        unsigned m_bitfields[2];
    } inherited_flags;

    struct NonInheritedFlags {
        unsigned m_bitfields[2];
    } noninherited_flags;
};

COMPILE_ASSERT(sizeof(RenderStyle) == sizeof(SameSizeAsRenderStyle), RenderStyle_should_stay_small);

inline RenderStyle& defaultStyle()
{
    static RenderStyle& style = RenderStyle::createDefaultStyle().leakRef();
    return style;
}

PassRef<RenderStyle> RenderStyle::create()
{
    return adoptRef(*new RenderStyle());
}

PassRef<RenderStyle> RenderStyle::createDefaultStyle()
{
    return adoptRef(*new RenderStyle(true));
}

PassRef<RenderStyle> RenderStyle::createAnonymousStyleWithDisplay(const RenderStyle* parentStyle, EDisplay display)
{
    auto newStyle = RenderStyle::create();
    newStyle.get().inheritFrom(parentStyle);
    newStyle.get().inheritUnicodeBidiFrom(parentStyle);
    newStyle.get().setDisplay(display);
    return newStyle;
}

PassRef<RenderStyle> RenderStyle::clone(const RenderStyle* other)
{
    return adoptRef(*new RenderStyle(*other));
}

ALWAYS_INLINE RenderStyle::RenderStyle()
    : m_box(defaultStyle().m_box)
    , visual(defaultStyle().visual)
    , m_background(defaultStyle().m_background)
    , surround(defaultStyle().surround)
    , rareNonInheritedData(defaultStyle().rareNonInheritedData)
    , rareInheritedData(defaultStyle().rareInheritedData)
    , inherited(defaultStyle().inherited)
#if ENABLE(SVG)
    , m_svgStyle(defaultStyle().m_svgStyle)
#endif
{
    setBitDefaults(); // Would it be faster to copy this from the default style?
    COMPILE_ASSERT((sizeof(InheritedFlags) <= 8), InheritedFlags_does_not_grow);
    COMPILE_ASSERT((sizeof(NonInheritedFlags) <= 8), NonInheritedFlags_does_not_grow);
}

ALWAYS_INLINE RenderStyle::RenderStyle(bool)
    : m_box(StyleBoxData::create())
    , visual(StyleVisualData::create())
    , m_background(StyleBackgroundData::create())
    , surround(StyleSurroundData::create())
    , rareNonInheritedData(StyleRareNonInheritedData::create())
    , rareInheritedData(StyleRareInheritedData::create())
    , inherited(StyleInheritedData::create())
#if ENABLE(SVG)
    , m_svgStyle(SVGRenderStyle::create())
#endif
{
    setBitDefaults();
}

ALWAYS_INLINE RenderStyle::RenderStyle(const RenderStyle& o)
    : RefCounted<RenderStyle>()
    , m_box(o.m_box)
    , visual(o.visual)
    , m_background(o.m_background)
    , surround(o.surround)
    , rareNonInheritedData(o.rareNonInheritedData)
    , rareInheritedData(o.rareInheritedData)
    , inherited(o.inherited)
#if ENABLE(SVG)
    , m_svgStyle(o.m_svgStyle)
#endif
    , inherited_flags(o.inherited_flags)
    , noninherited_flags(o.noninherited_flags)
{
}

void RenderStyle::inheritFrom(const RenderStyle* inheritParent, IsAtShadowBoundary isAtShadowBoundary)
{
    if (isAtShadowBoundary == AtShadowBoundary) {
        // Even if surrounding content is user-editable, shadow DOM should act as a single unit, and not necessarily be editable
        EUserModify currentUserModify = userModify();
        rareInheritedData = inheritParent->rareInheritedData;
        setUserModify(currentUserModify);
    } else
        rareInheritedData = inheritParent->rareInheritedData;
    inherited = inheritParent->inherited;
    inherited_flags = inheritParent->inherited_flags;
#if ENABLE(SVG)
    if (m_svgStyle != inheritParent->m_svgStyle)
        m_svgStyle.access()->inheritFrom(inheritParent->m_svgStyle.get());
#endif
}

void RenderStyle::copyNonInheritedFrom(const RenderStyle* other)
{
    m_box = other->m_box;
    visual = other->visual;
    m_background = other->m_background;
    surround = other->surround;
    rareNonInheritedData = other->rareNonInheritedData;
    // The flags are copied one-by-one because noninherited_flags contains a bunch of stuff other than real style data.
    noninherited_flags._effectiveDisplay = other->noninherited_flags._effectiveDisplay;
    noninherited_flags._originalDisplay = other->noninherited_flags._originalDisplay;
    noninherited_flags._overflowX = other->noninherited_flags._overflowX;
    noninherited_flags._overflowY = other->noninherited_flags._overflowY;
    noninherited_flags._vertical_align = other->noninherited_flags._vertical_align;
    noninherited_flags._clear = other->noninherited_flags._clear;
    noninherited_flags._position = other->noninherited_flags._position;
    noninherited_flags._floating = other->noninherited_flags._floating;
    noninherited_flags._table_layout = other->noninherited_flags._table_layout;
    noninherited_flags._unicodeBidi = other->noninherited_flags._unicodeBidi;
    noninherited_flags._page_break_before = other->noninherited_flags._page_break_before;
    noninherited_flags._page_break_after = other->noninherited_flags._page_break_after;
    noninherited_flags._page_break_inside = other->noninherited_flags._page_break_inside;
    noninherited_flags.explicitInheritance = other->noninherited_flags.explicitInheritance;
#if ENABLE(SVG)
    if (m_svgStyle != other->m_svgStyle)
        m_svgStyle.access()->copyNonInheritedFrom(other->m_svgStyle.get());
#endif
    ASSERT(zoom() == initialZoom());
}

bool RenderStyle::operator==(const RenderStyle& o) const
{
    // compare everything except the pseudoStyle pointer
    return inherited_flags == o.inherited_flags
        && noninherited_flags == o.noninherited_flags
        && m_box == o.m_box
        && visual == o.visual
        && m_background == o.m_background
        && surround == o.surround
        && rareNonInheritedData == o.rareNonInheritedData
        && rareInheritedData == o.rareInheritedData
        && inherited == o.inherited
#if ENABLE(SVG)
        && m_svgStyle == o.m_svgStyle
#endif
            ;
}

bool RenderStyle::isStyleAvailable() const
{
    return this != StyleResolver::styleNotYetAvailable();
}

bool RenderStyle::hasUniquePseudoStyle() const
{
    if (!m_cachedPseudoStyles || styleType() != NOPSEUDO)
        return false;

    for (size_t i = 0; i < m_cachedPseudoStyles->size(); ++i) {
        RenderStyle* pseudoStyle = m_cachedPseudoStyles->at(i).get();
        if (pseudoStyle->unique())
            return true;
    }

    return false;
}

RenderStyle* RenderStyle::getCachedPseudoStyle(PseudoId pid) const
{
    if (!m_cachedPseudoStyles || !m_cachedPseudoStyles->size())
        return 0;

    if (styleType() != NOPSEUDO) 
        return 0;

    for (size_t i = 0; i < m_cachedPseudoStyles->size(); ++i) {
        RenderStyle* pseudoStyle = m_cachedPseudoStyles->at(i).get();
        if (pseudoStyle->styleType() == pid)
            return pseudoStyle;
    }

    return 0;
}

RenderStyle* RenderStyle::addCachedPseudoStyle(PassRefPtr<RenderStyle> pseudo)
{
    if (!pseudo)
        return 0;

    ASSERT(pseudo->styleType() > NOPSEUDO);

    RenderStyle* result = pseudo.get();

    if (!m_cachedPseudoStyles)
        m_cachedPseudoStyles = adoptPtr(new PseudoStyleCache);

    m_cachedPseudoStyles->append(pseudo);

    return result;
}

void RenderStyle::removeCachedPseudoStyle(PseudoId pid)
{
    if (!m_cachedPseudoStyles)
        return;
    for (size_t i = 0; i < m_cachedPseudoStyles->size(); ++i) {
        RenderStyle* pseudoStyle = m_cachedPseudoStyles->at(i).get();
        if (pseudoStyle->styleType() == pid) {
            m_cachedPseudoStyles->remove(i);
            return;
        }
    }
}

bool RenderStyle::inheritedNotEqual(const RenderStyle* other) const
{
    return inherited_flags != other->inherited_flags
           || inherited != other->inherited
#if ENABLE(SVG)
           || m_svgStyle->inheritedNotEqual(other->m_svgStyle.get())
#endif
           || rareInheritedData != other->rareInheritedData;
}

#if ENABLE(IOS_TEXT_AUTOSIZING)
inline unsigned computeFontHash(const Font& font)
{
    unsigned hashCodes[2] = {
        CaseFoldingHash::hash(font.fontDescription().firstFamily().impl()),
        static_cast<unsigned>(font.fontDescription().specifiedSize())
    };
    return StringHasher::computeHash(reinterpret_cast<UChar*>(hashCodes), 2 * sizeof(unsigned) / sizeof(UChar));
}

uint32_t RenderStyle::hashForTextAutosizing() const
{
    // FIXME: Not a very smart hash. Could be improved upon. See <https://bugs.webkit.org/show_bug.cgi?id=121131>.
    uint32_t hash = 0;
    
    hash ^= rareNonInheritedData->m_appearance;
    hash ^= rareNonInheritedData->marginBeforeCollapse;
    hash ^= rareNonInheritedData->marginAfterCollapse;
    hash ^= rareNonInheritedData->lineClamp.value();
    hash ^= rareInheritedData->overflowWrap;
    hash ^= rareInheritedData->nbspMode;
    hash ^= rareInheritedData->lineBreak;
    hash ^= WTF::FloatHash<float>::hash(inherited->specifiedLineHeight.value());
    hash ^= computeFontHash(inherited->font);
    hash ^= inherited->horizontal_border_spacing;
    hash ^= inherited->vertical_border_spacing;
    hash ^= inherited_flags._box_direction;
    hash ^= inherited_flags.m_rtlOrdering;
    hash ^= noninherited_flags._position;
    hash ^= noninherited_flags._floating;
    hash ^= rareNonInheritedData->textOverflow;
    hash ^= rareInheritedData->textSecurity;
    return hash;
}

bool RenderStyle::equalForTextAutosizing(const RenderStyle* other) const
{
    return rareNonInheritedData->m_appearance == other->rareNonInheritedData->m_appearance
        && rareNonInheritedData->marginBeforeCollapse == other->rareNonInheritedData->marginBeforeCollapse
        && rareNonInheritedData->marginAfterCollapse == other->rareNonInheritedData->marginAfterCollapse
        && rareNonInheritedData->lineClamp == other->rareNonInheritedData->lineClamp
        && rareInheritedData->textSizeAdjust == other->rareInheritedData->textSizeAdjust
        && rareInheritedData->overflowWrap == other->rareInheritedData->overflowWrap
        && rareInheritedData->nbspMode == other->rareInheritedData->nbspMode
        && rareInheritedData->lineBreak == other->rareInheritedData->lineBreak
        && rareInheritedData->textSecurity == other->rareInheritedData->textSecurity
        && inherited->specifiedLineHeight == other->inherited->specifiedLineHeight
        && inherited->font.equalForTextAutoSizing(other->inherited->font)
        && inherited->horizontal_border_spacing == other->inherited->horizontal_border_spacing
        && inherited->vertical_border_spacing == other->inherited->vertical_border_spacing
        && inherited_flags._box_direction == other->inherited_flags._box_direction
        && inherited_flags.m_rtlOrdering == other->inherited_flags.m_rtlOrdering
        && noninherited_flags._position == other->noninherited_flags._position
        && noninherited_flags._floating == other->noninherited_flags._floating
        && rareNonInheritedData->textOverflow == other->rareNonInheritedData->textOverflow;
}
#endif // ENABLE(IOS_TEXT_AUTOSIZING)

bool RenderStyle::inheritedDataShared(const RenderStyle* other) const
{
    // This is a fast check that only looks if the data structures are shared.
    return inherited_flags == other->inherited_flags
        && inherited.get() == other->inherited.get()
#if ENABLE(SVG)
        && m_svgStyle.get() == other->m_svgStyle.get()
#endif
        && rareInheritedData.get() == other->rareInheritedData.get();
}

static bool positionChangeIsMovementOnly(const LengthBox& a, const LengthBox& b, const Length& width)
{
    // If any unit types are different, then we can't guarantee
    // that this was just a movement.
    if (a.left().type() != b.left().type()
        || a.right().type() != b.right().type()
        || a.top().type() != b.top().type()
        || a.bottom().type() != b.bottom().type())
        return false;

    // Only one unit can be non-auto in the horizontal direction and
    // in the vertical direction.  Otherwise the adjustment of values
    // is changing the size of the box.
    if (!a.left().isIntrinsicOrAuto() && !a.right().isIntrinsicOrAuto())
        return false;
    if (!a.top().isIntrinsicOrAuto() && !a.bottom().isIntrinsicOrAuto())
        return false;
    // If our width is auto and left or right is specified then this 
    // is not just a movement - we need to resize to our container.
    if ((!a.left().isIntrinsicOrAuto() || !a.right().isIntrinsicOrAuto()) && width.isIntrinsicOrAuto())
        return false;

    // One of the units is fixed or percent in both directions and stayed
    // that way in the new style.  Therefore all we are doing is moving.
    return true;
}

bool RenderStyle::changeRequiresLayout(const RenderStyle* other, unsigned& changedContextSensitiveProperties) const
{
    if (m_box->width() != other->m_box->width()
        || m_box->minWidth() != other->m_box->minWidth()
        || m_box->maxWidth() != other->m_box->maxWidth()
        || m_box->height() != other->m_box->height()
        || m_box->minHeight() != other->m_box->minHeight()
        || m_box->maxHeight() != other->m_box->maxHeight())
        return true;

    if (m_box->verticalAlign() != other->m_box->verticalAlign() || noninherited_flags._vertical_align != other->noninherited_flags._vertical_align)
        return true;

    if (m_box->boxSizing() != other->m_box->boxSizing())
        return true;

    if (surround->margin != other->surround->margin)
        return true;

    if (surround->padding != other->surround->padding)
        return true;

    if (rareNonInheritedData.get() != other->rareNonInheritedData.get()) {
        if (rareNonInheritedData->m_appearance != other->rareNonInheritedData->m_appearance 
            || rareNonInheritedData->marginBeforeCollapse != other->rareNonInheritedData->marginBeforeCollapse
            || rareNonInheritedData->marginAfterCollapse != other->rareNonInheritedData->marginAfterCollapse
            || rareNonInheritedData->lineClamp != other->rareNonInheritedData->lineClamp
            || rareNonInheritedData->textOverflow != other->rareNonInheritedData->textOverflow)
            return true;

        if (rareNonInheritedData->m_regionFragment != other->rareNonInheritedData->m_regionFragment)
            return true;

        if (rareNonInheritedData->m_wrapFlow != other->rareNonInheritedData->m_wrapFlow
            || rareNonInheritedData->m_wrapThrough != other->rareNonInheritedData->m_wrapThrough)
            return true;

#if ENABLE(CSS_SHAPES)
        if (rareNonInheritedData->m_shapeMargin != other->rareNonInheritedData->m_shapeMargin
            || rareNonInheritedData->m_shapePadding != other->rareNonInheritedData->m_shapePadding)
            return true;
#endif

        if (rareNonInheritedData->m_deprecatedFlexibleBox.get() != other->rareNonInheritedData->m_deprecatedFlexibleBox.get()
            && *rareNonInheritedData->m_deprecatedFlexibleBox.get() != *other->rareNonInheritedData->m_deprecatedFlexibleBox.get())
            return true;

        if (rareNonInheritedData->m_flexibleBox.get() != other->rareNonInheritedData->m_flexibleBox.get()
            && *rareNonInheritedData->m_flexibleBox.get() != *other->rareNonInheritedData->m_flexibleBox.get())
            return true;
        if (rareNonInheritedData->m_order != other->rareNonInheritedData->m_order
            || rareNonInheritedData->m_alignContent != other->rareNonInheritedData->m_alignContent
            || rareNonInheritedData->m_alignItems != other->rareNonInheritedData->m_alignItems
            || rareNonInheritedData->m_alignSelf != other->rareNonInheritedData->m_alignSelf
            || rareNonInheritedData->m_justifyContent != other->rareNonInheritedData->m_justifyContent)
            return true;

        // FIXME: We should add an optimized form of layout that just recomputes visual overflow.
        if (!rareNonInheritedData->shadowDataEquivalent(*other->rareNonInheritedData.get()))
            return true;

        if (!rareNonInheritedData->reflectionDataEquivalent(*other->rareNonInheritedData.get()))
            return true;

        if (rareNonInheritedData->m_multiCol.get() != other->rareNonInheritedData->m_multiCol.get()
            && *rareNonInheritedData->m_multiCol.get() != *other->rareNonInheritedData->m_multiCol.get())
            return true;

        if (rareNonInheritedData->m_transform.get() != other->rareNonInheritedData->m_transform.get()
            && *rareNonInheritedData->m_transform.get() != *other->rareNonInheritedData->m_transform.get()) {
#if USE(ACCELERATED_COMPOSITING)
            changedContextSensitiveProperties |= ContextSensitivePropertyTransform;
            // Don't return; keep looking for another change
#else
            UNUSED_PARAM(changedContextSensitiveProperties);
            return true;
#endif
        }

        if (rareNonInheritedData->m_grid.get() != other->rareNonInheritedData->m_grid.get()
            || rareNonInheritedData->m_gridItem.get() != other->rareNonInheritedData->m_gridItem.get())
            return true;

#if !USE(ACCELERATED_COMPOSITING)
        if (rareNonInheritedData.get() != other->rareNonInheritedData.get()) {
            if (rareNonInheritedData->m_transformStyle3D != other->rareNonInheritedData->m_transformStyle3D
                || rareNonInheritedData->m_backfaceVisibility != other->rareNonInheritedData->m_backfaceVisibility
                || rareNonInheritedData->m_perspective != other->rareNonInheritedData->m_perspective
                || rareNonInheritedData->m_perspectiveOriginX != other->rareNonInheritedData->m_perspectiveOriginX
                || rareNonInheritedData->m_perspectiveOriginY != other->rareNonInheritedData->m_perspectiveOriginY)
                return true;
        }
#endif

#if ENABLE(DASHBOARD_SUPPORT)
        // If regions change, trigger a relayout to re-calc regions.
        if (rareNonInheritedData->m_dashboardRegions != other->rareNonInheritedData->m_dashboardRegions)
            return true;
#endif

#if ENABLE(CSS_SHAPES)
        if (rareNonInheritedData->m_shapeInside != other->rareNonInheritedData->m_shapeInside)
            return true;
#endif
    }

    if (rareInheritedData.get() != other->rareInheritedData.get()) {
        if (rareInheritedData->highlight != other->rareInheritedData->highlight
            || rareInheritedData->indent != other->rareInheritedData->indent
#if ENABLE(CSS3_TEXT)
            || rareInheritedData->m_textAlignLast != other->rareInheritedData->m_textAlignLast
            || rareInheritedData->m_textIndentLine != other->rareInheritedData->m_textIndentLine
#endif
            || rareInheritedData->m_effectiveZoom != other->rareInheritedData->m_effectiveZoom
#if ENABLE(IOS_TEXT_AUTOSIZING)
            || rareInheritedData->textSizeAdjust != other->rareInheritedData->textSizeAdjust
#endif
            || rareInheritedData->wordBreak != other->rareInheritedData->wordBreak
            || rareInheritedData->overflowWrap != other->rareInheritedData->overflowWrap
            || rareInheritedData->nbspMode != other->rareInheritedData->nbspMode
            || rareInheritedData->lineBreak != other->rareInheritedData->lineBreak
            || rareInheritedData->textSecurity != other->rareInheritedData->textSecurity
            || rareInheritedData->hyphens != other->rareInheritedData->hyphens
            || rareInheritedData->hyphenationLimitBefore != other->rareInheritedData->hyphenationLimitBefore
            || rareInheritedData->hyphenationLimitAfter != other->rareInheritedData->hyphenationLimitAfter
            || rareInheritedData->hyphenationString != other->rareInheritedData->hyphenationString
            || rareInheritedData->locale != other->rareInheritedData->locale
            || rareInheritedData->m_rubyPosition != other->rareInheritedData->m_rubyPosition
            || rareInheritedData->textEmphasisMark != other->rareInheritedData->textEmphasisMark
            || rareInheritedData->textEmphasisPosition != other->rareInheritedData->textEmphasisPosition
            || rareInheritedData->textEmphasisCustomMark != other->rareInheritedData->textEmphasisCustomMark
            || rareInheritedData->m_textOrientation != other->rareInheritedData->m_textOrientation
            || rareInheritedData->m_tabSize != other->rareInheritedData->m_tabSize
            || rareInheritedData->m_lineBoxContain != other->rareInheritedData->m_lineBoxContain
            || rareInheritedData->m_lineGrid != other->rareInheritedData->m_lineGrid
#if ENABLE(CSS_IMAGE_ORIENTATION)
            || rareInheritedData->m_imageOrientation != other->rareInheritedData->m_imageOrientation
#endif
#if ENABLE(CSS_IMAGE_RESOLUTION)
            || rareInheritedData->m_imageResolutionSource != other->rareInheritedData->m_imageResolutionSource
            || rareInheritedData->m_imageResolutionSnap != other->rareInheritedData->m_imageResolutionSnap
            || rareInheritedData->m_imageResolution != other->rareInheritedData->m_imageResolution
#endif
            || rareInheritedData->m_lineSnap != other->rareInheritedData->m_lineSnap
            || rareInheritedData->m_lineAlign != other->rareInheritedData->m_lineAlign
#if ENABLE(ACCELERATED_OVERFLOW_SCROLLING)
            || rareInheritedData->useTouchOverflowScrolling != other->rareInheritedData->useTouchOverflowScrolling
#endif
            || rareInheritedData->listStyleImage != other->rareInheritedData->listStyleImage)
            return true;

        if (!rareInheritedData->shadowDataEquivalent(*other->rareInheritedData.get()))
            return true;

        if (textStrokeWidth() != other->textStrokeWidth())
            return true;
    }

#if ENABLE(TEXT_AUTOSIZING)
    if (visual->m_textAutosizingMultiplier != other->visual->m_textAutosizingMultiplier)
        return true;
#endif

    if (inherited->line_height != other->inherited->line_height
#if ENABLE(IOS_TEXT_AUTOSIZING)
        || inherited->specifiedLineHeight != other->inherited->specifiedLineHeight
#endif
        || inherited->font != other->inherited->font
        || inherited->horizontal_border_spacing != other->inherited->horizontal_border_spacing
        || inherited->vertical_border_spacing != other->inherited->vertical_border_spacing
        || inherited_flags._box_direction != other->inherited_flags._box_direction
        || inherited_flags.m_rtlOrdering != other->inherited_flags.m_rtlOrdering
        || noninherited_flags._position != other->noninherited_flags._position
        || noninherited_flags._floating != other->noninherited_flags._floating
        || noninherited_flags._originalDisplay != other->noninherited_flags._originalDisplay)
        return true;


    if (((int)noninherited_flags._effectiveDisplay) >= TABLE) {
        if (inherited_flags._border_collapse != other->inherited_flags._border_collapse
            || inherited_flags._empty_cells != other->inherited_flags._empty_cells
            || inherited_flags._caption_side != other->inherited_flags._caption_side
            || noninherited_flags._table_layout != other->noninherited_flags._table_layout)
            return true;

        // In the collapsing border model, 'hidden' suppresses other borders, while 'none'
        // does not, so these style differences can be width differences.
        if (inherited_flags._border_collapse
            && ((borderTopStyle() == BHIDDEN && other->borderTopStyle() == BNONE)
                || (borderTopStyle() == BNONE && other->borderTopStyle() == BHIDDEN)
                || (borderBottomStyle() == BHIDDEN && other->borderBottomStyle() == BNONE)
                || (borderBottomStyle() == BNONE && other->borderBottomStyle() == BHIDDEN)
                || (borderLeftStyle() == BHIDDEN && other->borderLeftStyle() == BNONE)
                || (borderLeftStyle() == BNONE && other->borderLeftStyle() == BHIDDEN)
                || (borderRightStyle() == BHIDDEN && other->borderRightStyle() == BNONE)
                || (borderRightStyle() == BNONE && other->borderRightStyle() == BHIDDEN)))
            return true;
    }

    if (noninherited_flags._effectiveDisplay == LIST_ITEM) {
        if (inherited_flags._list_style_type != other->inherited_flags._list_style_type
            || inherited_flags._list_style_position != other->inherited_flags._list_style_position)
            return true;
    }

    if (inherited_flags._text_align != other->inherited_flags._text_align
        || inherited_flags._text_transform != other->inherited_flags._text_transform
        || inherited_flags._direction != other->inherited_flags._direction
        || inherited_flags._white_space != other->inherited_flags._white_space
        || noninherited_flags._clear != other->noninherited_flags._clear
        || noninherited_flags._unicodeBidi != other->noninherited_flags._unicodeBidi)
        return true;

    // Check block flow direction.
    if (inherited_flags.m_writingMode != other->inherited_flags.m_writingMode)
        return true;

    // Check text combine mode.
    if (rareNonInheritedData->m_textCombine != other->rareNonInheritedData->m_textCombine)
        return true;

    // Overflow returns a layout hint.
    if (noninherited_flags._overflowX != other->noninherited_flags._overflowX
        || noninherited_flags._overflowY != other->noninherited_flags._overflowY)
        return true;

    // If our border widths change, then we need to layout.  Other changes to borders
    // only necessitate a repaint.
    if (borderLeftWidth() != other->borderLeftWidth()
        || borderTopWidth() != other->borderTopWidth()
        || borderBottomWidth() != other->borderBottomWidth()
        || borderRightWidth() != other->borderRightWidth())
        return true;

    // If the counter directives change, trigger a relayout to re-calculate counter values and rebuild the counter node tree.
    const CounterDirectiveMap* mapA = rareNonInheritedData->m_counterDirectives.get();
    const CounterDirectiveMap* mapB = other->rareNonInheritedData->m_counterDirectives.get();
    if (!(mapA == mapB || (mapA && mapB && *mapA == *mapB)))
        return true;

    if ((visibility() == COLLAPSE) != (other->visibility() == COLLAPSE))
        return true;

    if (rareNonInheritedData->hasOpacity() != other->rareNonInheritedData->hasOpacity()) {
        // FIXME: We would like to use SimplifiedLayout here, but we can't quite do that yet.
        // We need to make sure SimplifiedLayout can operate correctly on RenderInlines (we will need
        // to add a selfNeedsSimplifiedLayout bit in order to not get confused and taint every line).
        // In addition we need to solve the floating object issue when layers come and go. Right now
        // a full layout is necessary to keep floating object lists sane.
        return true;
    }

#if ENABLE(CSS_FILTERS)
    if (rareNonInheritedData->hasFilters() != other->rareNonInheritedData->hasFilters())
        return true;
#endif

    const QuotesData* quotesDataA = rareInheritedData->quotes.get();
    const QuotesData* quotesDataB = other->rareInheritedData->quotes.get();
    if (!(quotesDataA == quotesDataB || (quotesDataA && quotesDataB && *quotesDataA == *quotesDataB)))
        return true;

    if (position() != StaticPosition) {
        if (surround->offset != other->surround->offset) {
            // FIXME: We would like to use SimplifiedLayout for relative positioning, but we can't quite do that yet.
            // We need to make sure SimplifiedLayout can operate correctly on RenderInlines (we will need
            // to add a selfNeedsSimplifiedLayout bit in order to not get confused and taint every line).
            if (position() != AbsolutePosition)
                return true;

            // Optimize for the case where a positioned layer is moving but not changing size.
            if (!positionChangeIsMovementOnly(surround->offset, other->surround->offset, m_box->width()))
                return true;
        }
    }
    
    return false;
}

bool RenderStyle::changeRequiresPositionedLayoutOnly(const RenderStyle* other, unsigned&) const
{
    if (position() == StaticPosition)
        return false;

    if (surround->offset != other->surround->offset) {
        // Optimize for the case where a positioned layer is moving but not changing size.
        if (position() == AbsolutePosition && positionChangeIsMovementOnly(surround->offset, other->surround->offset, m_box->width()))
            return true;
    }
    
    return false;
}

bool RenderStyle::changeRequiresLayerRepaint(const RenderStyle* other, unsigned& changedContextSensitiveProperties) const
{
    if (position() != StaticPosition) {
        if (m_box->zIndex() != other->m_box->zIndex()
            || m_box->hasAutoZIndex() != other->m_box->hasAutoZIndex()
            || visual->clip != other->visual->clip
            || visual->hasClip != other->visual->hasClip)
            return true;
    }

#if ENABLE(CSS_COMPOSITING)
    if (rareNonInheritedData->m_effectiveBlendMode != other->rareNonInheritedData->m_effectiveBlendMode)
        return true;
#endif

    if (rareNonInheritedData->opacity != other->rareNonInheritedData->opacity) {
#if USE(ACCELERATED_COMPOSITING)
        changedContextSensitiveProperties |= ContextSensitivePropertyOpacity;
        // Don't return; keep looking for another change.
#else
        UNUSED_PARAM(changedContextSensitiveProperties);
        return true;
#endif
    }

#if ENABLE(CSS_FILTERS)
    if (rareNonInheritedData->m_filter.get() != other->rareNonInheritedData->m_filter.get()
        && *rareNonInheritedData->m_filter.get() != *other->rareNonInheritedData->m_filter.get()) {
#if USE(ACCELERATED_COMPOSITING)
        changedContextSensitiveProperties |= ContextSensitivePropertyFilter;
        // Don't return; keep looking for another change.
#else
        return true;
#endif
    }
#endif

    if (rareNonInheritedData->m_mask != other->rareNonInheritedData->m_mask
        || rareNonInheritedData->m_maskBoxImage != other->rareNonInheritedData->m_maskBoxImage)
        return true;

    return false;
}

bool RenderStyle::changeRequiresRepaint(const RenderStyle* other, unsigned&) const
{
    if (inherited_flags._visibility != other->inherited_flags._visibility
        || inherited_flags.m_printColorAdjust != other->inherited_flags.m_printColorAdjust
        || inherited_flags._insideLink != other->inherited_flags._insideLink
        || surround->border != other->surround->border
        || !m_background->isEquivalentForPainting(*other->m_background)
        || rareInheritedData->userModify != other->rareInheritedData->userModify
        || rareInheritedData->userSelect != other->rareInheritedData->userSelect
        || rareNonInheritedData->userDrag != other->rareNonInheritedData->userDrag
        || rareNonInheritedData->m_borderFit != other->rareNonInheritedData->m_borderFit
        || rareNonInheritedData->m_objectFit != other->rareNonInheritedData->m_objectFit
        || rareInheritedData->m_imageRendering != other->rareInheritedData->m_imageRendering)
        return true;

#if ENABLE(CSS_SHAPES)
    // FIXME: The current spec is being reworked to remove dependencies between exclusions and affected 
    // content. There's a proposal to use floats instead. In that case, wrap-shape should actually relayout 
    // the parent container. For sure, I will have to revisit this code, but for now I've added this in order 
    // to avoid having diff() == StyleDifferenceEqual where wrap-shapes actually differ.
    // Tracking bug: https://bugs.webkit.org/show_bug.cgi?id=62991
    if (rareNonInheritedData->m_shapeOutside != other->rareNonInheritedData->m_shapeOutside)
        return true;
#endif

    if (rareNonInheritedData->m_clipPath != other->rareNonInheritedData->m_clipPath)
        return true;

    return false;
}

bool RenderStyle::changeRequiresRepaintIfTextOrBorderOrOutline(const RenderStyle* other, unsigned&) const
{
    if (inherited->color != other->inherited->color
        || inherited_flags._text_decorations != other->inherited_flags._text_decorations
        || visual->textDecoration != other->visual->textDecoration
        || rareNonInheritedData->m_textDecorationStyle != other->rareNonInheritedData->m_textDecorationStyle
        || rareNonInheritedData->m_textDecorationColor != other->rareNonInheritedData->m_textDecorationColor
        || rareInheritedData->m_textDecorationSkip != other->rareInheritedData->m_textDecorationSkip
        || rareInheritedData->textFillColor != other->rareInheritedData->textFillColor
        || rareInheritedData->textStrokeColor != other->rareInheritedData->textStrokeColor
        || rareInheritedData->textEmphasisColor != other->rareInheritedData->textEmphasisColor
        || rareInheritedData->textEmphasisFill != other->rareInheritedData->textEmphasisFill)
        return true;

    return false;
}

bool RenderStyle::changeRequiresRecompositeLayer(const RenderStyle* other, unsigned&) const
{
#if USE(ACCELERATED_COMPOSITING)
    if (rareNonInheritedData.get() != other->rareNonInheritedData.get()) {
        if (rareNonInheritedData->m_transformStyle3D != other->rareNonInheritedData->m_transformStyle3D
            || rareNonInheritedData->m_backfaceVisibility != other->rareNonInheritedData->m_backfaceVisibility
            || rareNonInheritedData->m_perspective != other->rareNonInheritedData->m_perspective
            || rareNonInheritedData->m_perspectiveOriginX != other->rareNonInheritedData->m_perspectiveOriginX
            || rareNonInheritedData->m_perspectiveOriginY != other->rareNonInheritedData->m_perspectiveOriginY)
            return true;
    }
#else
    UNUSED_PARAM(other);
#endif
    return false;
}

StyleDifference RenderStyle::diff(const RenderStyle* other, unsigned& changedContextSensitiveProperties) const
{
    changedContextSensitiveProperties = ContextSensitivePropertyNone;

#if ENABLE(SVG)
    StyleDifference svgChange = StyleDifferenceEqual;
    if (m_svgStyle != other->m_svgStyle) {
        svgChange = m_svgStyle->diff(other->m_svgStyle.get());
        if (svgChange == StyleDifferenceLayout)
            return svgChange;
    }
#endif

    if (changeRequiresLayout(other, changedContextSensitiveProperties))
        return StyleDifferenceLayout;

#if ENABLE(SVG)
    // SVGRenderStyle::diff() might have returned StyleDifferenceRepaint, eg. if fill changes.
    // If eg. the font-size changed at the same time, we're not allowed to return StyleDifferenceRepaint,
    // but have to return StyleDifferenceLayout, that's why  this if branch comes after all branches
    // that are relevant for SVG and might return StyleDifferenceLayout.
    if (svgChange != StyleDifferenceEqual)
        return svgChange;
#endif

    if (changeRequiresPositionedLayoutOnly(other, changedContextSensitiveProperties))
        return StyleDifferenceLayoutPositionedMovementOnly;

    if (changeRequiresLayerRepaint(other, changedContextSensitiveProperties))
        return StyleDifferenceRepaintLayer;

    if (changeRequiresRepaint(other, changedContextSensitiveProperties))
        return StyleDifferenceRepaint;

#if USE(ACCELERATED_COMPOSITING)
    if (changeRequiresRecompositeLayer(other, changedContextSensitiveProperties))
        return StyleDifferenceRecompositeLayer;
#endif

    if (changeRequiresRepaintIfTextOrBorderOrOutline(other, changedContextSensitiveProperties))
        return StyleDifferenceRepaintIfTextOrBorderOrOutline;

    // Cursors are not checked, since they will be set appropriately in response to mouse events,
    // so they don't need to cause any repaint or layout.

    // Animations don't need to be checked either.  We always set the new style on the RenderObject, so we will get a chance to fire off
    // the resulting transition properly.
    return StyleDifferenceEqual;
}

bool RenderStyle::diffRequiresRepaint(const RenderStyle* style) const
{
    unsigned changedContextSensitiveProperties = 0;
    return changeRequiresRepaint(style, changedContextSensitiveProperties);
}

void RenderStyle::setClip(Length top, Length right, Length bottom, Length left)
{
    StyleVisualData* data = visual.access();
    data->clip.m_top = top;
    data->clip.m_right = right;
    data->clip.m_bottom = bottom;
    data->clip.m_left = left;
}

void RenderStyle::addCursor(PassRefPtr<StyleImage> image, const IntPoint& hotSpot)
{
    if (!rareInheritedData.access()->cursorData)
        rareInheritedData.access()->cursorData = CursorList::create();
    rareInheritedData.access()->cursorData->append(CursorData(image, hotSpot));