cssprimitivevalue.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

/*
 * (C) 1999-2003 Lars Knoll ([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 "CSSPrimitiveValue.h"

#include "CSSHelper.h"
#include "CSSPropertyNames.h"
#include "CSSStyleSheet.h"
#include "CSSValueKeywords.h"
#include "Color.h"
#include "Counter.h"
#include "ExceptionCode.h"
#include "Node.h"
#include "Pair.h"
#include "Rect.h"
#include "RenderStyle.h"
#include <wtf/ASCIICType.h>
#include <wtf/StdLibExtras.h>

#if ENABLE(DASHBOARD_SUPPORT)
#include "DashboardRegion.h"
#endif

using namespace WTF;

namespace WebCore {

// A more stylish solution than sharing would be to turn CSSPrimitiveValue (or CSSValues in general) into non-virtual,
// non-refcounted simple type with value semantics. In practice these sharing tricks get similar memory benefits 
// with less need for refactoring.

PassRefPtr<CSSPrimitiveValue> CSSPrimitiveValue::createIdentifier(int ident)
{
    static RefPtr<CSSPrimitiveValue>* identValueCache = new RefPtr<CSSPrimitiveValue>[numCSSValueKeywords];
    if (ident >= 0 && ident < numCSSValueKeywords) {
        RefPtr<CSSPrimitiveValue> primitiveValue = identValueCache[ident];
        if (!primitiveValue) {
            primitiveValue = adoptRef(new CSSPrimitiveValue(ident));
            identValueCache[ident] = primitiveValue;
        }
        return primitiveValue.release();
    } 
    return adoptRef(new CSSPrimitiveValue(ident));
}

PassRefPtr<CSSPrimitiveValue> CSSPrimitiveValue::createColor(unsigned rgbValue)
{
    typedef HashMap<unsigned, RefPtr<CSSPrimitiveValue> > ColorValueCache;
    static ColorValueCache* colorValueCache = new ColorValueCache;
    // These are the empty and deleted values of the hash table.
    if (rgbValue == Color::transparent) {
        static CSSPrimitiveValue* colorTransparent = new CSSPrimitiveValue(Color::transparent);
        return colorTransparent;
    }
    if (rgbValue == Color::white) {
        static CSSPrimitiveValue* colorWhite = new CSSPrimitiveValue(Color::white);
        return colorWhite;
    }
    RefPtr<CSSPrimitiveValue> primitiveValue = colorValueCache->get(rgbValue);
    if (primitiveValue)
        return primitiveValue.release();
    primitiveValue = adoptRef(new CSSPrimitiveValue(rgbValue));
    // Just wipe out the cache and start rebuilding when it gets too big.
    const int maxColorCacheSize = 512;
    if (colorValueCache->size() >= maxColorCacheSize)
        colorValueCache->clear();
    colorValueCache->add(rgbValue, primitiveValue);
    
    return primitiveValue.release();
}

PassRefPtr<CSSPrimitiveValue> CSSPrimitiveValue::create(double value, UnitTypes type)
{
    // Small integers are very common. Try to share them.
    const int cachedIntegerCount = 128;
    // Other common primitive types have UnitTypes smaller than this.
    const int maxCachedUnitType = CSS_PX;
    typedef RefPtr<CSSPrimitiveValue>(* IntegerValueCache)[maxCachedUnitType + 1];
    static IntegerValueCache integerValueCache = new RefPtr<CSSPrimitiveValue>[cachedIntegerCount][maxCachedUnitType + 1];
    if (type <= maxCachedUnitType && value >= 0 && value < cachedIntegerCount) {
        int intValue = static_cast<int>(value);
        if (value == intValue) {
            RefPtr<CSSPrimitiveValue> primitiveValue = integerValueCache[intValue][type];
            if (!primitiveValue) {
                primitiveValue = adoptRef(new CSSPrimitiveValue(value, type));
                integerValueCache[intValue][type] = primitiveValue;
            }
            return primitiveValue.release();
        }
    }

    return adoptRef(new CSSPrimitiveValue(value, type));
}

PassRefPtr<CSSPrimitiveValue> CSSPrimitiveValue::create(const String& value, UnitTypes type)
{
    return adoptRef(new CSSPrimitiveValue(value, type));
}

static const char* valueOrPropertyName(int valueOrPropertyID)
{
    if (const char* valueName = getValueName(valueOrPropertyID))
        return valueName;
    return getPropertyName(static_cast<CSSPropertyID>(valueOrPropertyID));
}

// "ident" from the CSS tokenizer, minus backslash-escape sequences
static bool isCSSTokenizerIdentifier(const String& string)
{
    const UChar* p = string.characters();
    const UChar* end = p + string.length();

    // -?
    if (p != end && p[0] == '-')
        ++p;

    // {nmstart}
    if (p == end || !(p[0] == '_' || p[0] >= 128 || isASCIIAlpha(p[0])))
        return false;
    ++p;

    // {nmchar}*
    for (; p != end; ++p) {
        if (!(p[0] == '_' || p[0] == '-' || p[0] >= 128 || isASCIIAlphanumeric(p[0])))
            return false;
    }

    return true;
}

// "url" from the CSS tokenizer, minus backslash-escape sequences
static bool isCSSTokenizerURL(const String& string)
{
    const UChar* p = string.characters();
    const UChar* end = p + string.length();

    for (; p != end; ++p) {
        UChar c = p[0];
        switch (c) {
            case '!':
            case '#':
            case '$':
            case '%':
            case '&':
                break;
            default:
                if (c < '*')
                    return false;
                if (c <= '~')
                    break;
                if (c < 128)
                    return false;
        }
    }

    return true;
}

// We use single quotes for now because markup.cpp uses double quotes.
static String quoteString(const String& string)
{
    // FIXME: Also need to escape characters like '\n'.
    String s = string;
    s.replace('\\', "\\\\");
    s.replace('\'', "\\'");
    return "'" + s + "'";
}

static String quoteStringIfNeeded(const String& string)
{
    return isCSSTokenizerIdentifier(string) ? string : quoteString(string);
}

static String quoteURLIfNeeded(const String& string)
{
    return isCSSTokenizerURL(string) ? string : quoteString(string);
}

CSSPrimitiveValue::CSSPrimitiveValue()
    : m_type(0)
{
}

CSSPrimitiveValue::CSSPrimitiveValue(int ident)
    : m_type(CSS_IDENT)
{
    m_value.ident = ident;
}

CSSPrimitiveValue::CSSPrimitiveValue(double num, UnitTypes type)
    : m_type(type)
{
    m_value.num = num;
}

CSSPrimitiveValue::CSSPrimitiveValue(const String& str, UnitTypes type)
    : m_type(type)
{
    if ((m_value.string = str.impl()))
        m_value.string->ref();
}

CSSPrimitiveValue::CSSPrimitiveValue(RGBA32 color)
    : m_type(CSS_RGBCOLOR)
{
    m_value.rgbcolor = color;
}

CSSPrimitiveValue::CSSPrimitiveValue(const Length& length)
{
    switch (length.type()) {
        case Auto:
            m_type = CSS_IDENT;
            m_value.ident = CSSValueAuto;
            break;
        case WebCore::Fixed:
            m_type = CSS_PX;
            m_value.num = length.value();
            break;
        case Intrinsic:
            m_type = CSS_IDENT;
            m_value.ident = CSSValueIntrinsic;
            break;
        case MinIntrinsic:
            m_type = CSS_IDENT;
            m_value.ident = CSSValueMinIntrinsic;
            break;
        case Percent:
            m_type = CSS_PERCENTAGE;
            m_value.num = length.percent();
            break;
        case Relative:
        case Static:
            ASSERT_NOT_REACHED();
            break;
    }
}

void CSSPrimitiveValue::init(PassRefPtr<Counter> c)
{
    m_type = CSS_COUNTER;
    m_value.counter = c.releaseRef();
}

void CSSPrimitiveValue::init(PassRefPtr<Rect> r)
{
    m_type = CSS_RECT;
    m_value.rect = r.releaseRef();
}

#if ENABLE(DASHBOARD_SUPPORT)
void CSSPrimitiveValue::init(PassRefPtr<DashboardRegion> r)
{
    m_type = CSS_DASHBOARD_REGION;
    m_value.region = r.releaseRef();
}
#endif

void CSSPrimitiveValue::init(PassRefPtr<Pair> p)
{
    m_type = CSS_PAIR;
    m_value.pair = p.releaseRef();
}

CSSPrimitiveValue::~CSSPrimitiveValue()
{
    cleanup();
}

void CSSPrimitiveValue::cleanup()
{
    switch (m_type) {
        case CSS_STRING:
        case CSS_URI:
        case CSS_ATTR:
        case CSS_PARSER_VARIABLE_FUNCTION_SYNTAX:
        case CSS_PARSER_HEXCOLOR:
            if (m_value.string)
                m_value.string->deref();
            break;
        case CSS_COUNTER:
            m_value.counter->deref();
            break;
        case CSS_RECT:
            m_value.rect->deref();
            break;
        case CSS_PAIR:
            m_value.pair->deref();
            break;
#if ENABLE(DASHBOARD_SUPPORT)
        case CSS_DASHBOARD_REGION:
            if (m_value.region)
                m_value.region->deref();
            break;
#endif
        default:
            break;
    }

    m_type = 0;
}

int CSSPrimitiveValue::computeLengthInt(RenderStyle* style)
{
    double result = computeLengthDouble(style);

    // This conversion is imprecise, often resulting in values of, e.g., 44.99998.  We
    // need to go ahead and round if we're really close to the next integer value.
    result += result < 0 ? -0.01 : +0.01;

    if (result > INT_MAX || result < INT_MIN)
        return 0;
    return static_cast<int>(result);
}

int CSSPrimitiveValue::computeLengthInt(RenderStyle* style, double multiplier)
{
    double result = computeLengthDouble(style, multiplier);

    // This conversion is imprecise, often resulting in values of, e.g., 44.99998.  We
    // need to go ahead and round if we're really close to the next integer value.
    result += result < 0 ? -0.01 : +0.01;

    if (result > INT_MAX || result < INT_MIN)
        return 0;
    return static_cast<int>(result);
}

const int intMaxForLength = 0x7ffffff; // max value for a 28-bit int
const int intMinForLength = (-0x7ffffff - 1); // min value for a 28-bit int

// Lengths expect an int that is only 28-bits, so we have to check for a different overflow.
int CSSPrimitiveValue::computeLengthIntForLength(RenderStyle* style)
{
    double result = computeLengthDouble(style);

    // This conversion is imprecise, often resulting in values of, e.g., 44.99998.  We
    // need to go ahead and round if we're really close to the next integer value.
    result += result < 0 ? -0.01 : +0.01;

    if (result > intMaxForLength || result < intMinForLength)
        return 0;
    return static_cast<int>(result);
}

// Lengths expect an int that is only 28-bits, so we have to check for a different overflow.
int CSSPrimitiveValue::computeLengthIntForLength(RenderStyle* style, double multiplier)
{
    double result = computeLengthDouble(style, multiplier);

    // This conversion is imprecise, often resulting in values of, e.g., 44.99998.  We
    // need to go ahead and round if we're really close to the next integer value.
    result += result < 0 ? -0.01 : +0.01;

    if (result > intMaxForLength || result < intMinForLength)
        return 0;
    return static_cast<int>(result);
}

short CSSPrimitiveValue::computeLengthShort(RenderStyle* style)
{
    double result = computeLengthDouble(style);

    // This conversion is imprecise, often resulting in values of, e.g., 44.99998.  We
    // need to go ahead and round if we're really close to the next integer value.
    result += result < 0 ? -0.01 : +0.01;

    if (result > SHRT_MAX || result < SHRT_MIN)
        return 0;
    return static_cast<short>(result);
}

short CSSPrimitiveValue::computeLengthShort(RenderStyle* style, double multiplier)
{
    double result = computeLengthDouble(style, multiplier);

    // This conversion is imprecise, often resulting in values of, e.g., 44.99998.  We
    // need to go ahead and round if we're really close to the next integer value.
    result += result < 0 ? -0.01 : +0.01;

    if (result > SHRT_MAX || result < SHRT_MIN)
        return 0;
    return static_cast<short>(result);
}

float CSSPrimitiveValue::computeLengthFloat(RenderStyle* style, bool computingFontSize)
{
    return static_cast<float>(computeLengthDouble(style, 1.0, computingFontSize));
}

float CSSPrimitiveValue::computeLengthFloat(RenderStyle* style, double multiplier, bool computingFontSize)
{
    return static_cast<float>(computeLengthDouble(style, multiplier, computingFontSize));
}

double CSSPrimitiveValue::computeLengthDouble(RenderStyle* style, double multiplier, bool computingFontSize)
{
    unsigned short type = primitiveType();

    // We do not apply the zoom factor when we are computing the value of the font-size property.  The zooming
    // for font sizes is much more complicated, since we have to worry about enforcing the minimum font size preference
    // as well as enforcing the implicit "smart minimum."  In addition the CSS property text-size-adjust is used to
    // prevent text from zooming at all.  Therefore we will not apply the zoom here if we are computing font-size.
    bool applyZoomMultiplier = !computingFontSize;

    double factor = 1.0;
    switch (type) {
        case CSS_EMS:
            applyZoomMultiplier = false;
            factor = computingFontSize ? style->fontDescription().specifiedSize() : style->fontDescription().computedSize();
            break;
        case CSS_EXS:
            // FIXME: We have a bug right now where the zoom will be applied twice to EX units.
            // We really need to compute EX using fontMetrics for the original specifiedSize and not use
            // our actual constructed rendering font.
            applyZoomMultiplier = false;
            factor = style->font().xHeight();
            break;
        case CSS_PX:
            break;
        case CSS_CM:
            factor = cssPixelsPerInch / 2.54; // (2.54 cm/in)
            break;
        case CSS_MM:
            factor = cssPixelsPerInch / 25.4;
            break;
        case CSS_IN:
            factor = cssPixelsPerInch;
            break;
        case CSS_PT:
            factor = cssPixelsPerInch / 72.0;
            break;
        case CSS_PC:
            // 1 pc == 12 pt
            factor = cssPixelsPerInch * 12.0 / 72.0;
            break;
        default:
            return -1.0;
    }

    double result = getDoubleValue() * factor;
    if (!applyZoomMultiplier || multiplier == 1.0)
        return result;
     
    // Any original result that was >= 1 should not be allowed to fall below 1.  This keeps border lines from
    // vanishing.
    double zoomedResult = result * multiplier;
    if (result >= 1.0)
        zoomedResult = max(1.0, zoomedResult);
    return zoomedResult;
}

void CSSPrimitiveValue::setFloatValue(unsigned short unitType, double floatValue, ExceptionCode& ec)
{
    ec = 0;

    // FIXME: check if property supports this type
    if (m_type > CSS_DIMENSION) {
        ec = SYNTAX_ERR;
        return;