Cascade declared property values instead of applying values on top of each other

Source/core/css/resolver/CascadedValues.cpp

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "core/css/resolver/CascadedValues.h"
+
+#include "core/css/CSSValuePool.h"
+#include "core/css/StylePropertySet.h"
+#include "core/css/resolver/MatchResult.h"
+#include "core/css/resolver/StyleBuilder.h"
+#include "core/css/resolver/StyleResolver.h"
+#include "core/css/resolver/StyleResolverState.h"
+#include <algorithm>
+
+namespace blink {
+
+// We want properties in their prefixed and non-prefixed variants to cascade
+// together, so we map them to the same property before adding to the cascade.
+static CSSPropertyID resolveProperty(CSSPropertyID property, TextDirection direction, WritingMode writingMode)
+{
+    switch (property) {
+    case CSSPropertyWebkitBorderEndColor:
+    case CSSPropertyWebkitBorderBeforeStyle:
+    case CSSPropertyWebkitBorderEndStyle:
+    case CSSPropertyWebkitPaddingStart:
+    case CSSPropertyWebkitBorderStartWidth:
+    case CSSPropertyWebkitMaxLogicalWidth:
+    case CSSPropertyWebkitLogicalHeight:
+    case CSSPropertyWebkitMinLogicalWidth:
+    case CSSPropertyWebkitBorderBeforeWidth:
+    case CSSPropertyWebkitPaddingBefore:
+    case CSSPropertyWebkitBorderBeforeColor:
+    case CSSPropertyWebkitMarginEnd:
+    case CSSPropertyWebkitBorderAfterWidth:
+    case CSSPropertyWebkitMinLogicalHeight:
+    case CSSPropertyWebkitBorderEndWidth:
+    case CSSPropertyWebkitPaddingEnd:
+    case CSSPropertyWebkitLogicalWidth:
+    case CSSPropertyWebkitBorderAfterColor:
+    case CSSPropertyWebkitMaxLogicalHeight:
+    case CSSPropertyWebkitBorderStartColor:
+    case CSSPropertyWebkitBorderAfterStyle:
+    case CSSPropertyWebkitPaddingAfter:
+    case CSSPropertyWebkitBorderStartStyle:
+    case CSSPropertyWebkitMarginBefore:
+    case CSSPropertyWebkitMarginStart:
+    case CSSPropertyWebkitMarginAfter:
+        return CSSProperty::resolveDirectionAwareProperty(property, direction, writingMode);
+    case CSSPropertyWebkitBackfaceVisibility:
+        return CSSPropertyBackfaceVisibility;
+    case CSSPropertyWebkitBackgroundClip:
+        return CSSPropertyBackgroundClip;
+    case CSSPropertyWebkitBackgroundOrigin:
+        return CSSPropertyBackgroundOrigin;
+    case CSSPropertyWebkitBackgroundSize:
+        return CSSPropertyBackgroundSize;
+    case CSSPropertyWebkitBoxShadow:
+        return CSSPropertyBoxShadow;
+    case CSSPropertyWebkitTransform:
+        return CSSPropertyTransform;
+    case CSSPropertyWebkitTransformStyle:
+        return CSSPropertyTransformStyle;
+    case CSSPropertyWebkitPerspective:
+        return CSSPropertyPerspective;
+    case CSSPropertyWebkitPerspectiveOrigin:
+        return CSSPropertyPerspectiveOrigin;
+    // Used by editing when the css3 text decorations flag is off
+    case CSSPropertyTextDecoration:
+        ASSERT(!RuntimeEnabledFeatures::css3TextDecorationsEnabled());
+        return CSSPropertyTextDecorationLine;
+    // As per css3-text, word-wrap is an alias for overflow-wrap
+    case CSSPropertyWordWrap:
+        return CSSPropertyOverflowWrap;
+    default:
+        return property;
+    }
+}
+
+CascadedValues::CascadedValues(StyleResolverState& state, const MatchResult& matchResult, bool onlyAddUARules)
+    : m_state(state)
+{
+    memset(m_values, 0, sizeof(m_values));
+    if (m_state.style()->insideLink())
+        memset(m_visitedLinkValues, 0, sizeof(m_visitedLinkValues));
+
+    // The MatchResult has rules in UA - User - Author order, although we only
+    // use user rules for callback selectors.
+    addMatchResult(matchResult, CSSPropertyDirection, CSSPropertyWebkitWritingMode);
+    applyValues(CSSPropertyDirection, CSSPropertyWebkitWritingMode);
+    m_direction = state.style()->direction();
+    m_writingMode = state.style()->writingMode();
+
+    COMPILE_ASSERT(CSSPropertyColor == CSSPropertyWebkitWritingMode + 1, CSS_color_is_after_super_high_priority);
+    if (onlyAddUARules) {
+        addMatchResultRange(matchResult, false, matchResult.ranges.firstUARule, matchResult.ranges.lastUARule, CSSPropertyColor, convertToCSSPropertyID(lastCSSProperty));
+    } else {
+        addMatchResult(matchResult, CSSPropertyColor, convertToCSSPropertyID(lastCSSProperty));
+    }
+
+    std::sort(setProperties.begin(), setProperties.end());
+    std::sort(setVisitedProperties.begin(), setVisitedProperties.end());
+}
+
+void CascadedValues::addMatchResult(const MatchResult& matchResult, CSSPropertyID firstId, CSSPropertyID lastId)
+{
+    addMatchResultRange(matchResult, false, 0, matchResult.matchedProperties.size() - 1, firstId, lastId);
+    addMatchResultRange(matchResult, true, matchResult.ranges.firstAuthorRule, matchResult.ranges.lastAuthorRule, firstId, lastId);
+    addMatchResultRange(matchResult, true, matchResult.ranges.firstUARule, matchResult.ranges.lastUARule, firstId, lastId);
+}
+
+void CascadedValues::addMatchResultRange(const MatchResult& matchResult, bool isImportant, int firstIndex, int lastIndex, CSSPropertyID firstId, CSSPropertyID lastId)
+{
+    if (firstIndex == -1)
+        return;
+
+    for (int i = firstIndex; i <= lastIndex; ++i) {
+        const MatchedProperties& matchedProperties = matchResult.matchedProperties[i];
+        SelectorChecker::LinkMatchMask linkMatchType = SelectorChecker::MatchLink;
+        if (m_state.style()->insideLink())
+            linkMatchType = static_cast<SelectorChecker::LinkMatchMask>(matchedProperties.m_types.linkMatchType);
+        addStylePropertySet(matchedProperties.properties.get(), matchResult.matchedRules[i], isImportant, firstId, lastId, static_cast<PropertyWhitelistType>(matchedProperties.m_types.whitelistType), linkMatchType);
+    }
+}
+
+void CascadedValues::addStylePropertySet(const StylePropertySet* properties, const StyleRule* rule, bool isImportant, CSSPropertyID first, CSSPropertyID last, PropertyWhitelistType propertyWhitelistType, SelectorChecker::LinkMatchMask linkMatchType)
+{
+    unsigned propertyCount = properties->propertyCount();
+    for (unsigned i = 0; i < propertyCount; ++i) {
+        StylePropertySet::PropertyReference current = properties->propertyAt(i);
+        if (isImportant != current.isImportant())
+            continue;
+
+        CSSPropertyID property = current.id();
+        if (property < first || property > last)
+            continue;
+
+        // FIXME: We should check the whitelist, otherwise we might run into
+        // problems with e.g. foo:first-letter { all: inherit; }
+        if (property == CSSPropertyAll) {
+            addAllProperty(current.value(), linkMatchType);
+            continue;
+        }
+
+        if (propertyWhitelistType == PropertyWhitelistCue && !StyleResolver::isValidCueStyleProperty(property))
+            continue;
+        if (propertyWhitelistType == PropertyWhitelistFirstLetter && !StyleResolver::isValidFirstLetterStyleProperty(property))
+            continue;
+        addValue(current.id(), current.value(), rule, linkMatchType);
+    }
+}
+
+void CascadedValues::addValue(CSSPropertyID property, CSSValue* value, const StyleRule* rule, SelectorChecker::LinkMatchMask linkMatchType)
+{
+    property = resolveProperty(property, m_direction, m_writingMode);
+
+    if (property == CSSPropertyInternalCallback) {
+        ASSERT(value->isPrimitiveValue() && toCSSPrimitiveValue(value)->getValueID() == CSSValueInternalPresence);
+        m_state.style()->addCallbackSelector(rule->selectorList().selectorsText());
+        return;
+    }
+
+    // Shorthands that are not expanded in the parser need special handling here.
+    // The shorthand property occurs earlier in CSSPropertyNames.in than its
+    // longhands so we can cascade properly. If a longhand value is explicitly
+    // set, with higher priority than the shorthand, then the value computed
+    // from the shorthand will be overriden.
+
+    // FIXME: font should always be expanded by the parser; crbug.com/353932
+    if (property == CSSPropertyFont) {
+        clearCascadedValue(CSSPropertyLineHeight);
+        clearCascadedValue(CSSPropertyFontStyle);
+        clearCascadedValue(CSSPropertyFontFamily);
+        clearCascadedValue(CSSPropertyFontVariant);
+        clearCascadedValue(CSSPropertyFontWeight);
+        clearCascadedValue(CSSPropertyFontStretch);
+        clearCascadedValue(CSSPropertyFontSize);
+    }
+
+    // -webkit-border-image sometimes also sets border-*-width, but properly
+    // cascading this requires too much effort
+    if (property == CSSPropertyWebkitBorderImage) {
+        clearCascadedValue(CSSPropertyBorderImageSource);
+        clearCascadedValue(CSSPropertyBorderImageSlice);
+        clearCascadedValue(CSSPropertyBorderImageWidth);
+        clearCascadedValue(CSSPropertyBorderImageOutset);
+        clearCascadedValue(CSSPropertyBorderImageRepeat);
+    }
+
+    if (linkMatchType & SelectorChecker::MatchLink)
+        setCascadedValue(property, value);
+    if (linkMatchType & SelectorChecker::MatchVisited)
+        setCascadedVisitedLinkValue(property, value);
+}
+
+void CascadedValues::addAllProperty(CSSValue* value, SelectorChecker::LinkMatchMask linkMatchType)
+{
+    if (!value->isInitialValue() && !value->isInheritedValue()) {
+        ASSERT(value->isPrimitiveValue() && toCSSPrimitiveValue(value)->getValueID() == CSSValueUnset);
+        value = nullptr;
+    }
+
+    for (int i = firstCSSProperty; i <= lastCSSProperty; ++i) {
+        CSSPropertyID property = convertToCSSPropertyID(i);
+        if (CSSProperty::isAffectedByAllProperty(property))
+            addValue(property, value, nullptr, linkMatchType);
+    }
+}
+
+void CascadedValues::setCascadedValue(CSSPropertyID id, CSSValue* value)
+{
+    if (!m_values[id - firstCSSProperty])
+        setProperties.append(id);
+    m_values[id - firstCSSProperty] = value;
+}
+
+void CascadedValues::setCascadedVisitedLinkValue(CSSPropertyID id, CSSValue* value)
+{
+    ASSERT(m_state.style()->insideLink());
+    if (!m_visitedLinkValues[id - firstCSSProperty])
+        setVisitedProperties.append(id);
+    m_visitedLinkValues[id - firstCSSProperty] = value;
+}
+
+void CascadedValues::applyValues(CSSPropertyID first, CSSPropertyID last, bool inheritedOnly)
+{
+    for (size_t i = 0; i < setProperties.size(); i++) {
+        CSSPropertyID property = setProperties[i];
+        if (property < first || property > last)
+            continue;
+        // We might not have a value due to the shorthand special-cases in addValue
+        if (!cascadedValue(property))
+            continue;
+        if (!inheritedOnly || CSSProperty::isInheritedProperty(property))
+            StyleBuilder::applyProperty(property, m_state, cascadedValue(property));
+    }
+
+    if (!m_state.style()->insideLink())
+        return;
+
+    m_state.setApplyPropertyToRegularStyle(false);
+    m_state.setApplyPropertyToVisitedLinkStyle(true);
+    for (size_t i = 0; i < setVisitedProperties.size(); i++) {
+        CSSPropertyID property = setVisitedProperties[i];
+        if (property < first || property > last)
+            continue;
+        ASSERT(cascadedVisitedLinkValue(property));
+        if (!inheritedOnly || CSSProperty::isInheritedProperty(property))
+            StyleBuilder::applyProperty(property, m_state, cascadedVisitedLinkValue(property));
+    }
+    m_state.setApplyPropertyToRegularStyle(true);
+    m_state.setApplyPropertyToVisitedLinkStyle(false);
+}
+
+
+} // namespace blink