Resolve color:currentcolor during computing

The keyword value "currentcolor" should be preserved rather than being
replaced by the CSS-wide keyword "inherit" during parsing.

components/script/dom/element.rs

@@ -103,7 +103,7 @@ use style::matching::{common_style_affecting_attributes, rare_style_affecting_at
 use style::parser::ParserContextExtraData;
 use style::properties::{DeclaredValue, Importance};
 use style::properties::{PropertyDeclaration, PropertyDeclarationBlock, parse_style_attribute};
-use style::properties::longhands::{background_image, border_spacing, font_family, font_size, overflow_x};
+use style::properties::longhands::{self, background_image, border_spacing, font_family, font_size, overflow_x};
 use style::restyle_hints::RESTYLE_SELF;
 use style::rule_tree::CascadeLevel;
 use style::selector_parser::{NonTSPseudoClass, RestyleDamage, SelectorImpl, SelectorParser};
@@ -111,7 +111,7 @@ use style::sink::Push;
 use style::stylist::ApplicableDeclarationBlock;
 use style::thread_state;
 use style::values::CSSFloat;
-use style::values::specified::{self, CSSColor, CSSRGBA};
+use style::values::specified::{self, CSSColor};
 use stylesheet_loader::StylesheetOwner;
 
 // TODO: Update focus state when the top-level browsing context gains or loses system focus,
@@ -441,10 +441,13 @@ impl LayoutElementHelpers for LayoutJS<Element> {
 
         if let Some(color) = color {
             hints.push(from_declaration(
-                PropertyDeclaration::Color(DeclaredValue::Value(CSSRGBA {
+                PropertyDeclaration::Color(DeclaredValue::Value(
-                    parsed: color,
+                    longhands::color::SpecifiedValue(CSSColor {
-                    authored: None,
+                        parsed: Color::RGBA(color),
-                }))));
+                        authored: None,
+                    })
+                ))
+            ));
         }
 
         let font_family = if let Some(this) = self.downcast::<HTMLFontElement>() {

components/style/properties/longhand/color.mako.rs

@@ -6,30 +6,46 @@
 
 <% data.new_style_struct("Color", inherited=True) %>
 
-<%helpers:raw_longhand name="color" need_clone="True" animatable="True"
+<%helpers:longhand name="color" need_clone="True" animatable="True"
-                       spec="https://drafts.csswg.org/css-color/#color">
+                   spec="https://drafts.csswg.org/css-color/#color">
     use cssparser::Color as CSSParserColor;
     use cssparser::RGBA;
+    use std::fmt;
+    use style_traits::ToCss;
+    use values::HasViewportPercentage;
     use values::specified::{CSSColor, CSSRGBA};
 
     impl ToComputedValue for SpecifiedValue {
         type ComputedValue = computed_value::T;
 
         #[inline]
-        fn to_computed_value(&self, _context: &Context) -> computed_value::T {
+        fn to_computed_value(&self, context: &Context) -> computed_value::T {
-            self.parsed
+            match self.0.parsed {
+                CSSParserColor::RGBA(rgba) => rgba,
+                CSSParserColor::CurrentColor => context.inherited_style.get_color().clone_color(),
+            }
         }
 
         #[inline]
         fn from_computed_value(computed: &computed_value::T) -> Self {
-            CSSRGBA {
+            SpecifiedValue(CSSColor {
-                parsed: *computed,
+                parsed: CSSParserColor::RGBA(*computed),
                 authored: None,
-            }
+            })
+        }
+    }
+
+    #[derive(Clone, PartialEq, Debug)]
+    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+    pub struct SpecifiedValue(pub CSSColor);
+    no_viewport_percentage!(SpecifiedValue);
+
+    impl ToCss for SpecifiedValue {
+        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+            self.0.to_css(dest)
         }
     }
 
-    pub type SpecifiedValue = CSSRGBA;
     pub mod computed_value {
         use cssparser;
         pub type T = cssparser::RGBA;
@@ -38,16 +54,7 @@
     pub fn get_initial_value() -> computed_value::T {
         RGBA::new(0, 0, 0, 255) // black
     }
-    pub fn parse_specified(context: &ParserContext, input: &mut Parser)
+    pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
-                           -> Result<DeclaredValue<SpecifiedValue>, ()> {
+        CSSColor::parse(context, input).map(SpecifiedValue)
-        let value = try!(CSSColor::parse(context, input));
-        let rgba = match value.parsed {
-            CSSParserColor::RGBA(rgba) => rgba,
-            CSSParserColor::CurrentColor => return Ok(DeclaredValue::Inherit)
-        };
-        Ok(DeclaredValue::Value(CSSRGBA {
-            parsed: rgba,
-            authored: value.authored,
-        }))
     }
-</%helpers:raw_longhand>
+</%helpers:longhand>

ports/geckolib/glue.rs

@@ -1102,7 +1102,8 @@ pub extern "C" fn Servo_DeclarationBlock_SetColorValue(declarations:
     use cssparser::Color;
     use style::gecko::values::convert_nscolor_to_rgba;
     use style::properties::{DeclaredValue, PropertyDeclaration, LonghandId};
-    use style::values::specified::{CSSColor, CSSRGBA};
+    use style::properties::longhands;
+    use style::values::specified::CSSColor;
 
     let declarations = RwLock::<PropertyDeclarationBlock>::as_arc(&declarations);
     let long = get_longhand_from_id!(property);
@@ -1114,7 +1115,7 @@ pub extern "C" fn Servo_DeclarationBlock_SetColorValue(declarations:
         BorderRightColor => color,
         BorderBottomColor => color,
         BorderLeftColor => color,
-        Color => CSSRGBA { parsed: rgba, authored: None },
+        Color => longhands::color::SpecifiedValue(color),
         BackgroundColor => color,
     };
     declarations.write().declarations.push((prop, Default::default()));