renderstyle.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 * Copyright (C) 1999 Antti Koivisto ([e-mail])
 * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. 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 "CSSStyleSelector.h"
#include "CachedImage.h"
#include "CounterContent.h"
#include "FontSelector.h"
#include "RenderArena.h"
#include "RenderObject.h"
#include "StyleImage.h"
#include <wtf/StdLibExtras.h>
#include <algorithm>

namespace WebCore {

inline RenderStyle* defaultStyle()
{
    static RenderStyle* s_defaultStyle = RenderStyle::createDefaultStyle().releaseRef();
    return s_defaultStyle;
}

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

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

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

RenderStyle::RenderStyle()
    : box(defaultStyle()->box)
    , visual(defaultStyle()->visual)
    , background(defaultStyle()->background)
    , surround(defaultStyle()->surround)
    , rareNonInheritedData(defaultStyle()->rareNonInheritedData)
    , rareInheritedData(defaultStyle()->rareInheritedData)
    , inherited(defaultStyle()->inherited)
    , m_pseudoState(PseudoUnknown)
    , m_affectedByAttributeSelectors(false)
    , m_unique(false)
    , m_affectedByEmpty(false)
    , m_emptyState(false)
    , m_childrenAffectedByFirstChildRules(false)
    , m_childrenAffectedByLastChildRules(false)
    , m_childrenAffectedByDirectAdjacentRules(false)
    , m_childrenAffectedByForwardPositionalRules(false)
    , m_childrenAffectedByBackwardPositionalRules(false)
    , m_firstChildState(false)
    , m_lastChildState(false)
    , m_childIndex(0)
#if ENABLE(SVG)
    , m_svgStyle(defaultStyle()->m_svgStyle)
#endif
{
    setBitDefaults(); // Would it be faster to copy this from the default style?
}

RenderStyle::RenderStyle(bool)
    : m_pseudoState(PseudoUnknown)
    , m_affectedByAttributeSelectors(false)
    , m_unique(false)
    , m_affectedByEmpty(false)
    , m_emptyState(false)
    , m_childrenAffectedByFirstChildRules(false)
    , m_childrenAffectedByLastChildRules(false)
    , m_childrenAffectedByDirectAdjacentRules(false)
    , m_childrenAffectedByForwardPositionalRules(false)
    , m_childrenAffectedByBackwardPositionalRules(false)
    , m_firstChildState(false)
    , m_lastChildState(false)
    , m_childIndex(0)
{
    setBitDefaults();

    box.init();
    visual.init();
    background.init();
    surround.init();
    rareNonInheritedData.init();
    rareNonInheritedData.access()->flexibleBox.init();
    rareNonInheritedData.access()->marquee.init();
    rareNonInheritedData.access()->m_multiCol.init();
    rareNonInheritedData.access()->m_transform.init();
    rareInheritedData.init();
    inherited.init();

#if ENABLE(SVG)
    m_svgStyle.init();
#endif
}

RenderStyle::RenderStyle(const RenderStyle& o)
    : RefCounted<RenderStyle>()
    , inherited_flags(o.inherited_flags)
    , noninherited_flags(o.noninherited_flags)
    , box(o.box)
    , visual(o.visual)
    , background(o.background)
    , surround(o.surround)
    , rareNonInheritedData(o.rareNonInheritedData)
    , rareInheritedData(o.rareInheritedData)
    , inherited(o.inherited)
    , m_pseudoState(o.m_pseudoState)
    , m_affectedByAttributeSelectors(false)
    , m_unique(false)
    , m_affectedByEmpty(false)
    , m_emptyState(false)
    , m_childrenAffectedByFirstChildRules(false)
    , m_childrenAffectedByLastChildRules(false)
    , m_childrenAffectedByDirectAdjacentRules(false)
    , m_childrenAffectedByForwardPositionalRules(false)
    , m_childrenAffectedByBackwardPositionalRules(false)
    , m_firstChildState(false)
    , m_lastChildState(false)
    , m_childIndex(0)
#if ENABLE(SVG)
    , m_svgStyle(o.m_svgStyle)
#endif
{
}

void RenderStyle::inheritFrom(const RenderStyle* inheritParent)
{
    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
}

RenderStyle::~RenderStyle()
{
}

bool RenderStyle::operator==(const RenderStyle& o) const
{
    // compare everything except the pseudoStyle pointer
    return inherited_flags == o.inherited_flags &&
            noninherited_flags == o.noninherited_flags &&
            box == o.box &&
            visual == o.visual &&
            background == o.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 != CSSStyleSelector::styleNotYetAvailable();
}

static inline int pseudoBit(PseudoId pseudo)
{
    return 1 << (pseudo - 1);
}

bool RenderStyle::hasPseudoStyle(PseudoId pseudo) const
{
    ASSERT(pseudo > NOPSEUDO);
    ASSERT(pseudo < FIRST_INTERNAL_PSEUDOID);
    return pseudoBit(pseudo) & noninherited_flags._pseudoBits;
}

void RenderStyle::setHasPseudoStyle(PseudoId pseudo)
{
    ASSERT(pseudo > NOPSEUDO);
    ASSERT(pseudo < FIRST_INTERNAL_PSEUDOID);
    noninherited_flags._pseudoBits |= pseudoBit(pseudo);
}

RenderStyle* RenderStyle::getCachedPseudoStyle(PseudoId pid)
{
    if (!m_cachedPseudoStyle || styleType() != NOPSEUDO)
        return 0;
    RenderStyle* ps = m_cachedPseudoStyle.get();
    while (ps && ps->styleType() != pid)
        ps = ps->m_cachedPseudoStyle.get();
    return ps;
}

RenderStyle* RenderStyle::addCachedPseudoStyle(PassRefPtr<RenderStyle> pseudo)
{
    if (!pseudo)
        return 0;
    pseudo->m_cachedPseudoStyle = m_cachedPseudoStyle;
    m_cachedPseudoStyle = pseudo;
    return m_cachedPseudoStyle.get();
}

bool RenderStyle::inheritedNotEqual(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;
}

static bool positionedObjectMoved(const LengthBox& a, const LengthBox& b)
{
    // 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;

    // 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;
}

/*
  compares two styles. The result gives an idea of the action that
  needs to be taken when replacing the old style with a new one.

  CbLayout: The containing block of the object needs a relayout.
  Layout: the RenderObject needs a relayout after the style change
  Visible: The change is visible, but no relayout is needed
  NonVisible: The object does need neither repaint nor relayout after
       the change.

  ### TODO:
  A lot can be optimised here based on the display type, lots of
  optimisations are unimplemented, and currently result in the
  worst case result causing a relayout of the containing block.
*/
StyleDifference RenderStyle::diff(const RenderStyle* other, unsigned& changedContextSensitiveProperties) const
{
    changedContextSensitiveProperties = ContextSensitivePropertyNone;

#if ENABLE(SVG)
    // This is horribly inefficient.  Eventually we'll have to integrate
    // this more directly by calling: Diff svgDiff = svgStyle->diff(other)
    // and then checking svgDiff and returning from the appropriate places below.
    if (m_svgStyle != other->m_svgStyle)
        return StyleDifferenceLayout;
#endif