Auto merge of #18359 - emilio:bye-color-mako, r=nox

style: Move color to use predefined_type.

I want to play with autogenerating style structs, and color is the smallest
struct out there.

However, moving it out of the mako file is a requirement. This patch does that.

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

@@ -8,48 +8,22 @@
 
 <% from data import to_rust_ident %>
 
-<%helpers:longhand name="color" need_clone="True"
-                   animation_value_type="AnimatedRGBA"
-                   ignored_when_colors_disabled="True"
-                   flags="APPLIES_TO_FIRST_LETTER APPLIES_TO_FIRST_LINE APPLIES_TO_PLACEHOLDER"
-                   spec="https://drafts.csswg.org/css-color/#color">
-    use cssparser::RGBA;
-    use values::specified::{AllowQuirks, Color};
+${helpers.predefined_type(
+    "color",
+    "ColorPropertyValue",
+    "::cssparser::RGBA::new(0, 0, 0, 255)",
+    animation_value_type="AnimatedRGBA",
+    flags="APPLIES_TO_FIRST_LETTER APPLIES_TO_FIRST_LINE APPLIES_TO_PLACEHOLDER",
+    ignored_when_colors_disabled="True",
+    spec="https://drafts.csswg.org/css-color/#color",
+    need_clone="True"
+)}
 
-    impl ToComputedValue for SpecifiedValue {
-        type ComputedValue = computed_value::T;
-
-        #[inline]
-        fn to_computed_value(&self, context: &Context) -> computed_value::T {
-            self.0.to_computed_value(context)
-                .to_rgba(context.builder.get_parent_color().clone_color())
-        }
-
-        #[inline]
-        fn from_computed_value(computed: &computed_value::T) -> Self {
-            SpecifiedValue(Color::rgba(*computed).into())
-        }
-    }
-
-    #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-    #[derive(Clone, Debug, PartialEq, ToCss)]
-    pub struct SpecifiedValue(pub Color);
-
-    pub mod computed_value {
-        use cssparser;
-        pub type T = cssparser::RGBA;
-    }
-    #[inline]
-    pub fn get_initial_value() -> computed_value::T {
-        RGBA::new(0, 0, 0, 255) // black
-    }
-    pub fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
-                         -> Result<SpecifiedValue, ParseError<'i>> {
-        Color::parse_quirky(context, input, AllowQuirks::Yes).map(SpecifiedValue)
-    }
-
-    // FIXME(#15973): Add servo support for system colors
-    % if product == "gecko":
+// FIXME(#15973): Add servo support for system colors
+//
+// FIXME(emilio): Move outside of mako.
+% if product == "gecko":
+pub mod system_colors {
     <%
         # These are actually parsed. See nsCSSProps::kColorKTable
         system_colors = """activeborder activecaption appworkspace background buttonface
@@ -84,10 +58,12 @@
                           IMESelectedConvertedTextBackground IMESelectedConvertedTextForeground
                           IMESelectedConvertedTextUnderline SpellCheckerUnderline""".split()
     %>
+    use cssparser::Parser;
     use gecko_bindings::bindings::Gecko_GetLookAndFeelSystemColor;
     use gecko_bindings::structs::root::mozilla::LookAndFeel_ColorID;
     use std::fmt;
     use style_traits::ToCss;
+    use values::computed::{Context, ToComputedValue};
 
     pub type SystemColor = LookAndFeel_ColorID;
 
@@ -105,6 +81,7 @@
 
     impl ToComputedValue for SystemColor {
         type ComputedValue = u32; // nscolor
+
         #[inline]
         fn to_computed_value(&self, cx: &Context) -> Self::ComputedValue {
             unsafe {
@@ -120,7 +97,7 @@
     }
 
     impl SystemColor {
-            pub fn parse<'i, 't>(input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
+        pub fn parse<'i, 't>(input: &mut Parser<'i, 't>,) -> Result<Self, ()> {
             ascii_case_insensitive_phf_map! {
                 color_name -> SystemColor = {
                     % for color in system_colors:
@@ -129,13 +106,9 @@
                 }
             }
 
-                let ident = input.expect_ident()?;
-                if let Some(color) = color_name(&ident) {
-                    Ok(*color)
-                } else {
-                    Err(SelectorParseError::UnexpectedIdent(ident.clone()).into())
+            let ident = input.expect_ident().map_err(|_| ())?;
+            color_name(ident).cloned().ok_or(())
         }
     }
-        }
-    % endif
-</%helpers:longhand>
+}
+% endif

components/style/values/computed/color.rs

@@ -26,6 +26,9 @@ pub struct Color {
 /// Computed value type for the specified RGBAColor.
 pub type RGBAColor = RGBA;
 
+/// The computed value of the `color` property.
+pub type ColorPropertyValue = RGBA;
+
 impl Color {
     /// Returns a numeric color representing the given RGBA value.
     pub fn rgba(rgba: RGBA) -> Color {

components/style/values/computed/mod.rs

@@ -35,7 +35,7 @@ pub use self::background::BackgroundSize;
 pub use self::border::{BorderImageSlice, BorderImageWidth, BorderImageSideWidth};
 pub use self::border::{BorderRadius, BorderCornerRadius};
 pub use self::box_::VerticalAlign;
-pub use self::color::{Color, RGBAColor};
+pub use self::color::{Color, ColorPropertyValue, RGBAColor};
 pub use self::effects::{BoxShadow, Filter, SimpleShadow};
 pub use self::flex::FlexBasis;
 pub use self::image::{Gradient, GradientItem, Image, ImageLayer, LineDirection, MozImageRect};

components/style/values/specified/color.rs

@@ -10,7 +10,7 @@ use gecko_bindings::structs::nscolor;
 use itoa;
 use parser::{ParserContext, Parse};
 #[cfg(feature = "gecko")]
-use properties::longhands::color::SystemColor;
+use properties::longhands::system_colors::SystemColor;
 use std::fmt;
 use std::io::Write;
 use style_traits::{ToCss, ParseError, StyleParseError, ValueParseError};
@@ -329,3 +329,32 @@ impl From<Color> for RGBAColor {
         RGBAColor(color)
     }
 }
+
+/// Specified value for the "color" property, which resolves the `currentcolor`
+/// keyword to the parent color instead of self's color.
+#[derive(Clone, Debug, PartialEq, ToCss)]
+pub struct ColorPropertyValue(pub Color);
+
+impl ToComputedValue for ColorPropertyValue {
+    type ComputedValue = RGBA;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> RGBA {
+        self.0.to_computed_value(context)
+            .to_rgba(context.builder.get_parent_color().clone_color())
+    }
+
+    #[inline]
+    fn from_computed_value(computed: &RGBA) -> Self {
+        ColorPropertyValue(Color::rgba(*computed).into())
+    }
+}
+
+impl Parse for ColorPropertyValue {
+    fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        Color::parse_quirky(context, input, AllowQuirks::Yes).map(ColorPropertyValue)
+    }
+}

components/style/values/specified/mod.rs

@@ -32,7 +32,7 @@ pub use self::background::BackgroundSize;
 pub use self::border::{BorderCornerRadius, BorderImageSlice, BorderImageWidth};
 pub use self::border::{BorderImageSideWidth, BorderRadius, BorderSideWidth};
 pub use self::box_::VerticalAlign;
-pub use self::color::{Color, RGBAColor};
+pub use self::color::{Color, ColorPropertyValue, RGBAColor};
 pub use self::effects::{BoxShadow, Filter, SimpleShadow};
 pub use self::flex::FlexBasis;
 #[cfg(feature = "gecko")]