Implement parsing of all gradients

components/layout/display_list_builder.rs

@@ -53,7 +53,7 @@ use style::properties::{self, ServoComputedValues};
 use style::properties::style_structs;
 use style::values::RGBA;
 use style::values::computed;
-use style::values::computed::{LengthOrNone, LengthOrPercentage, LengthOrPercentageOrAuto, LinearGradient};
+use style::values::computed::{Gradient, GradientKind, LengthOrNone, LengthOrPercentage, LengthOrPercentageOrAuto};
 use style::values::specified::{AngleOrCorner, HorizontalDirection, VerticalDirection};
 use style_traits::cursor::Cursor;
 use table_cell::CollapsedBordersForCell;
@@ -167,13 +167,13 @@ pub trait FragmentDisplayListBuilding {
 
     /// Adds the display items necessary to paint the background linear gradient of this fragment
     /// to the appropriate section of the display list.
-    fn build_display_list_for_background_linear_gradient(&self,
-                                                         state: &mut DisplayListBuildState,
-                                                         display_list_section: DisplayListSection,
-                                                         absolute_bounds: &Rect<Au>,
-                                                         clip: &ClippingRegion,
-                                                         gradient: &LinearGradient,
-                                                         style: &ServoComputedValues);
+    fn build_display_list_for_background_gradient(&self,
+                                                  state: &mut DisplayListBuildState,
+                                                  display_list_section: DisplayListSection,
+                                                  absolute_bounds: &Rect<Au>,
+                                                  clip: &ClippingRegion,
+                                                  gradient: &Gradient,
+                                                  style: &ServoComputedValues);
 
     /// Adds the display items necessary to paint the borders of this fragment to a display list if
     /// necessary.
@@ -402,13 +402,16 @@ impl FragmentDisplayListBuilding for Fragment {
         for (i, background_image) in background.background_image.0.iter().enumerate().rev() {
             match background_image.0 {
                 None => {}
-                Some(computed::Image::LinearGradient(ref gradient)) => {
-                    self.build_display_list_for_background_linear_gradient(state,
-                                                                           display_list_section,
-                                                                           &bounds,
-                                                                           &clip,
-                                                                           gradient,
-                                                                           style);
+                Some(computed::Image::Gradient(ref gradient)) => {
+                    // FIXME: Radial gradients aren't implemented yet.
+                    if let GradientKind::Linear(_) = gradient.gradient_kind {
+                        self.build_display_list_for_background_gradient(state,
+                                                                        display_list_section,
+                                                                        &bounds,
+                                                                        &clip,
+                                                                        gradient,
+                                                                        style);
+                    }
                 }
                 Some(computed::Image::Url(ref image_url, ref _extra_data)) => {
                     self.build_display_list_for_background_image(state,
@@ -636,36 +639,45 @@ impl FragmentDisplayListBuilding for Fragment {
         }
     }
 
-    fn build_display_list_for_background_linear_gradient(&self,
-                                                         state: &mut DisplayListBuildState,
-                                                         display_list_section: DisplayListSection,
-                                                         absolute_bounds: &Rect<Au>,
-                                                         clip: &ClippingRegion,
-                                                         gradient: &LinearGradient,
-                                                         style: &ServoComputedValues) {
+    fn build_display_list_for_background_gradient(&self,
+                                                  state: &mut DisplayListBuildState,
+                                                  display_list_section: DisplayListSection,
+                                                  absolute_bounds: &Rect<Au>,
+                                                  clip: &ClippingRegion,
+                                                  gradient: &Gradient,
+                                                  style: &ServoComputedValues) {
         let mut clip = clip.clone();
         clip.intersect_rect(absolute_bounds);
 
 
-        let angle = match gradient.angle_or_corner {
-            AngleOrCorner::Angle(angle) => angle.radians(),
-            AngleOrCorner::Corner(horizontal, vertical) => {
-                // This the angle for one of the diagonals of the box. Our angle
-                // will either be this one, this one + PI, or one of the other
-                // two perpendicular angles.
-                let atan = (absolute_bounds.size.height.to_f32_px() /
-                            absolute_bounds.size.width.to_f32_px()).atan();
-                match (horizontal, vertical) {
-                    (HorizontalDirection::Right, VerticalDirection::Bottom)
-                        => f32::consts::PI - atan,
-                    (HorizontalDirection::Left, VerticalDirection::Bottom)
-                        => f32::consts::PI + atan,
-                    (HorizontalDirection::Right, VerticalDirection::Top)
-                        => atan,
-                    (HorizontalDirection::Left, VerticalDirection::Top)
-                        => -atan,
+        // FIXME: Repeating gradients aren't implemented yet.
+        if gradient.repeating {
+          return;
+        }
+        let angle = if let GradientKind::Linear(angle_or_corner) = gradient.gradient_kind {
+            match angle_or_corner {
+                AngleOrCorner::Angle(angle) => angle.radians(),
+                AngleOrCorner::Corner(horizontal, vertical) => {
+                    // This the angle for one of the diagonals of the box. Our angle
+                    // will either be this one, this one + PI, or one of the other
+                    // two perpendicular angles.
+                    let atan = (absolute_bounds.size.height.to_f32_px() /
+                                absolute_bounds.size.width.to_f32_px()).atan();
+                    match (horizontal, vertical) {
+                        (HorizontalDirection::Right, VerticalDirection::Bottom)
+                            => f32::consts::PI - atan,
+                        (HorizontalDirection::Left, VerticalDirection::Bottom)
+                            => f32::consts::PI + atan,
+                        (HorizontalDirection::Right, VerticalDirection::Top)
+                            => atan,
+                        (HorizontalDirection::Left, VerticalDirection::Top)
+                            => -atan,
+                    }
                 }
             }
+        } else {
+            // FIXME: Radial gradients aren't implemented yet.
+            return;
         };
 
         // Get correct gradient line length, based on:

components/style/properties/helpers.mako.rs

@@ -173,8 +173,10 @@
             use parser::{ParserContext, ParserContextExtraData};
             use properties::{CSSWideKeyword, DeclaredValue, Shorthand};
         % endif
+        #[allow(unused_imports)]
         use cascade_info::CascadeInfo;
         use error_reporting::ParseErrorReporter;
+        use parser::Parse;
         use properties::longhands;
         use properties::property_bit_field::PropertyBitField;
         use properties::{ComputedValues, PropertyDeclaration};
@@ -565,6 +567,8 @@
     <%self:shorthand name="${name}" sub_properties="${
             ' '.join(sub_property_pattern % side
                      for side in ['top', 'right', 'bottom', 'left'])}">
+        #[allow(unused_imports)]
+        use parser::Parse;
         use super::parse_four_sides;
         use values::specified;
 

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

@@ -15,6 +15,7 @@ ${helpers.predefined_type("opacity",
 <%helpers:vector_longhand name="box-shadow" allow_empty="True" animatable="True">
     use cssparser::{self, ToCss};
     use std::fmt;
+    use parser::Parse;
     use values::LocalToCss;
     use values::HasViewportPercentage;
 
@@ -355,6 +356,7 @@ ${helpers.predefined_type("opacity",
 
     pub fn parse(_context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
         use app_units::Au;
+        use parser::Parse;
         use std::ascii::AsciiExt;
         use values::specified::Length;
 
@@ -1199,6 +1201,7 @@ pub struct OriginParseResult {
 }
 
 pub fn parse_origin(_: &ParserContext, input: &mut Parser) -> Result<OriginParseResult,()> {
+    use parser::Parse;
     use values::specified::{LengthOrPercentage, Percentage};
     let (mut horizontal, mut vertical, mut depth) = (None, None, None);
     loop {

components/style/values/computed/image.rs

@@ -0,0 +1,460 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! CSS handling for the computed value of
+//! [`image`][image]s
+//!
+//! [image]: https://drafts.csswg.org/css-images/#image-values
+
+use cssparser::Color as CSSColor;
+use std::fmt;
+use url::Url;
+use values::LocalToCss;
+use values::computed::{Context, Length, LengthOrPercentage, ToComputedValue};
+use values::computed::position::Position;
+use values::specified;
+use values::specified::{AngleOrCorner, SizeKeyword, UrlExtraData};
+
+
+impl ToComputedValue for specified::Image {
+    type ComputedValue = Image;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> Image {
+        match *self {
+            specified::Image::Url(ref url, ref extra_data) => {
+                Image::Url(url.clone(), extra_data.clone())
+            },
+            specified::Image::Gradient(ref gradient) => {
+                Image::Gradient(gradient.to_computed_value(context))
+            }
+        }
+    }
+
+    #[inline]
+    fn from_computed_value(computed: &Image) -> Self {
+        match *computed {
+            Image::Url(ref url, ref extra_data) => {
+                specified::Image::Url(url.clone(), extra_data.clone())
+            },
+            Image::Gradient(ref linear_gradient) => {
+                specified::Image::Gradient(
+                    ToComputedValue::from_computed_value(linear_gradient)
+                )
+            }
+        }
+    }
+}
+
+/// Computed values for an image according to CSS-IMAGES.
+/// https://drafts.csswg.org/css-images/#image-values
+#[derive(Clone, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum Image {
+    Url(Url, UrlExtraData),
+    Gradient(Gradient),
+}
+
+impl fmt::Debug for Image {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Image::Url(ref url, ref _extra_data) => write!(f, "url(\"{}\")", url),
+            Image::Gradient(ref grad) => {
+                if grad.repeating {
+                    let _ = write!(f, "repeating-");
+                }
+                match grad.gradient_kind {
+                    GradientKind::Linear(_) => write!(f, "linear-gradient({:?})", grad),
+                    GradientKind::Radial(_, _) => write!(f, "radial-gradient({:?})", grad),
+                }
+            },
+        }
+    }
+}
+
+impl ::cssparser::ToCss for Image {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        use values::LocalToCss;
+        match *self {
+            Image::Url(ref url, _) => {
+                url.to_css(dest)
+            }
+            Image::Gradient(ref gradient) => gradient.to_css(dest)
+        }
+    }
+}
+
+/// Computed values for a CSS gradient.
+/// https://drafts.csswg.org/css-images/#gradients
+#[derive(Clone, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub struct Gradient {
+    /// The color stops.
+    pub stops: Vec<ColorStop>,
+    /// True if this is a repeating gradient.
+    pub repeating: bool,
+    /// Gradient kind can be linear or radial.
+    pub gradient_kind: GradientKind,
+}
+
+impl ::cssparser::ToCss for Gradient {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        if self.repeating {
+            try!(dest.write_str("repeating-"));
+        }
+        match self.gradient_kind {
+            GradientKind::Linear(angle_or_corner) => {
+                try!(dest.write_str("linear-gradient("));
+                try!(angle_or_corner.to_css(dest));
+            },
+            GradientKind::Radial(ref shape, position) => {
+                try!(dest.write_str("radial-gradient("));
+                try!(shape.to_css(dest));
+                try!(dest.write_str(" at "));
+                try!(position.to_css(dest));
+            },
+        }
+        for stop in &self.stops {
+            try!(dest.write_str(", "));
+            try!(stop.to_css(dest));
+        }
+        try!(dest.write_str(")"));
+        Ok(())
+    }
+}
+
+impl fmt::Debug for Gradient {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self.gradient_kind {
+            GradientKind::Linear(angle_or_corner) => {
+                let _ = write!(f, "{:?}", angle_or_corner);
+            },
+            GradientKind::Radial(ref shape, position) => {
+                let _ = write!(f, "{:?} at {:?}", shape, position);
+            },
+        }
+
+        for stop in &self.stops {
+            let _ = write!(f, ", {:?}", stop);
+        }
+        Ok(())
+    }
+}
+
+impl ToComputedValue for specified::Gradient {
+    type ComputedValue = Gradient;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> Gradient {
+        let specified::Gradient {
+            ref stops,
+            repeating,
+            ref gradient_kind
+        } = *self;
+        Gradient {
+            stops: stops.iter().map(|s| s.to_computed_value(context)).collect(),
+            repeating: repeating,
+            gradient_kind: gradient_kind.to_computed_value(context),
+        }
+    }
+    #[inline]
+    fn from_computed_value(computed: &Gradient) -> Self {
+        let Gradient {
+            ref stops,
+            repeating,
+            ref gradient_kind
+        } = *computed;
+        specified::Gradient {
+            stops: stops.iter().map(ToComputedValue::from_computed_value).collect(),
+            repeating: repeating,
+            gradient_kind: ToComputedValue::from_computed_value(gradient_kind),
+        }
+    }
+}
+
+/// Computed values for CSS linear or radial gradients.
+/// https://drafts.csswg.org/css-images/#gradients
+#[derive(Clone, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum GradientKind {
+    Linear(AngleOrCorner),
+    Radial(EndingShape, Position),
+}
+
+impl ToComputedValue for specified::GradientKind {
+    type ComputedValue = GradientKind;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> GradientKind {
+        match *self {
+            specified::GradientKind::Linear(angle_or_corner) => {
+                GradientKind::Linear(angle_or_corner)
+            },
+            specified::GradientKind::Radial(ref shape, position) => {
+                GradientKind::Radial(shape.to_computed_value(context),
+                                     position.to_computed_value(context))
+            },
+        }
+    }
+    #[inline]
+    fn from_computed_value(computed: &GradientKind) -> Self {
+        match *computed {
+            GradientKind::Linear(angle_or_corner) => {
+                specified::GradientKind::Linear(ToComputedValue::from_computed_value(&angle_or_corner))
+            },
+            GradientKind::Radial(ref shape, position) => {
+                specified::GradientKind::Radial(ToComputedValue::from_computed_value(shape),
+                                                ToComputedValue::from_computed_value(&position))
+            },
+        }
+    }
+}
+
+/// Computed values for one color stop in a linear gradient.
+/// https://drafts.csswg.org/css-images/#typedef-color-stop-list
+#[derive(Clone, PartialEq, Copy)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub struct ColorStop {
+    /// The color of this stop.
+    pub color: CSSColor,
+
+    /// The position of this stop. If not specified, this stop is placed halfway between the
+    /// point that precedes it and the point that follows it per CSS-IMAGES § 3.4.
+    pub position: Option<LengthOrPercentage>,
+}
+
+impl ::cssparser::ToCss for ColorStop {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        try!(self.color.to_css(dest));
+        if let Some(position) = self.position {
+            try!(dest.write_str(" "));
+            try!(position.to_css(dest));
+        }
+        Ok(())
+    }
+}
+
+impl fmt::Debug for ColorStop {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let _ = write!(f, "{:?}", self.color);
+        self.position.map(|pos| {
+            let _ = write!(f, " {:?}", pos);
+        });
+        Ok(())
+    }
+}
+
+impl ToComputedValue for specified::ColorStop {
+    type ComputedValue = ColorStop;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> ColorStop {
+        ColorStop {
+            color: self.color.parsed,
+            position: match self.position {
+                None => None,
+                Some(value) => Some(value.to_computed_value(context)),
+            },
+        }
+    }
+    #[inline]
+    fn from_computed_value(computed: &ColorStop) -> Self {
+        specified::ColorStop {
+            color: ToComputedValue::from_computed_value(&computed.color),
+            position: match computed.position {
+                None => None,
+                Some(value) => Some(ToComputedValue::from_computed_value(&value)),
+            },
+        }
+    }
+}
+
+/// Computed values for EndingShape
+/// https://drafts.csswg.org/css-images/#valdef-radial-gradient-ending-shape
+#[derive(Clone, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum EndingShape {
+    Circle(LengthOrKeyword),
+    Ellipse(LengthOrPercentageOrKeyword),
+}
+
+impl ::cssparser::ToCss for EndingShape {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            EndingShape::Circle(ref length) => {
+                try!(dest.write_str("circle "));
+                try!(length.to_css(dest));
+            },
+            EndingShape::Ellipse(ref length) => {
+                try!(dest.write_str("ellipse "));
+                try!(length.to_css(dest));
+            },
+        }
+        Ok(())
+    }
+}
+
+impl fmt::Debug for EndingShape {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            EndingShape::Circle(ref length) => {
+                let _ = write!(f, "circle {:?}", length);
+            },
+            EndingShape::Ellipse(ref length) => {
+                let _ = write!(f, "ellipse {:?}", length);
+            }
+        }
+        Ok(())
+    }
+}
+
+impl ToComputedValue for specified::GradientEndingShape {
+    type ComputedValue = EndingShape;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> EndingShape {
+        match *self {
+            specified::GradientEndingShape::Circle(ref length) => {
+                EndingShape::Circle(length.to_computed_value(context))
+            },
+            specified::GradientEndingShape::Ellipse(ref length) => {
+                EndingShape::Ellipse(length.to_computed_value(context))
+            },
+        }
+    }
+    #[inline]
+    fn from_computed_value(computed: &EndingShape) -> Self {
+        match *computed {
+            EndingShape::Circle(ref length) => {
+                specified::GradientEndingShape::Circle(ToComputedValue::from_computed_value(length))
+            },
+            EndingShape::Ellipse(ref length) => {
+                specified::GradientEndingShape::Ellipse(ToComputedValue::from_computed_value(length))
+            },
+        }
+    }
+}
+
+/// https://drafts.csswg.org/css-images/#valdef-radial-gradient-size
+#[derive(Clone, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum LengthOrKeyword {
+    Length(Length),
+    Keyword(SizeKeyword),
+}
+
+impl ::cssparser::ToCss for LengthOrKeyword {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            LengthOrKeyword::Length(ref length) => length.to_css(dest),
+            LengthOrKeyword::Keyword(keyword) => keyword.to_css(dest),
+        }
+    }
+}
+
+impl fmt::Debug for LengthOrKeyword {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            LengthOrKeyword::Length(ref length) => {
+                let _ = write!(f, "{:?}", length);
+            },
+            LengthOrKeyword::Keyword(keyword) => {
+                let _ = write!(f, "{:?}", keyword);
+            },
+        }
+        Ok(())
+    }
+}
+
+impl ToComputedValue for specified::LengthOrKeyword {
+    type ComputedValue = LengthOrKeyword;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> LengthOrKeyword {
+        match *self {
+            specified::LengthOrKeyword::Length(length) => {
+                LengthOrKeyword::Length(length.to_computed_value(context))
+            },
+            specified::LengthOrKeyword::Keyword(keyword) => {
+                LengthOrKeyword::Keyword(keyword)
+            },
+        }
+    }
+    #[inline]
+    fn from_computed_value(computed: &LengthOrKeyword) -> Self {
+        match *computed {
+            LengthOrKeyword::Length(length) => {
+                specified::LengthOrKeyword::Length(ToComputedValue::from_computed_value(&length))
+            },
+            LengthOrKeyword::Keyword(keyword) => {
+                specified::LengthOrKeyword::Keyword(keyword)
+            },
+        }
+    }
+}
+
+/// https://drafts.csswg.org/css-images/#valdef-radial-gradient-size
+#[derive(Clone, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum LengthOrPercentageOrKeyword {
+    LengthOrPercentage(LengthOrPercentage, LengthOrPercentage),
+    Keyword(SizeKeyword),
+}
+
+impl ::cssparser::ToCss for LengthOrPercentageOrKeyword {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            LengthOrPercentageOrKeyword::LengthOrPercentage(ref first_len, second_len) => {
+                try!(first_len.to_css(dest));
+                try!(dest.write_str(" "));
+                second_len.to_css(dest)
+            },
+            LengthOrPercentageOrKeyword::Keyword(keyword) => keyword.to_css(dest),
+        }
+    }
+}
+
+impl fmt::Debug for LengthOrPercentageOrKeyword {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            LengthOrPercentageOrKeyword::LengthOrPercentage(ref first_len, second_len) => {
+                let _ = write!(f, "{:?} {:?}", first_len, second_len);
+            },
+            LengthOrPercentageOrKeyword::Keyword(keyword) => {
+                let _ = write!(f, "{:?}", keyword);
+            },
+        }
+        Ok(())
+    }
+}
+
+impl ToComputedValue for specified::LengthOrPercentageOrKeyword {
+    type ComputedValue = LengthOrPercentageOrKeyword;
+
+    #[inline]
+    fn to_computed_value(&self, context: &Context) -> LengthOrPercentageOrKeyword {
+        match *self {
+            specified::LengthOrPercentageOrKeyword::LengthOrPercentage(first_len, second_len) => {
+                LengthOrPercentageOrKeyword::LengthOrPercentage(first_len.to_computed_value(context),
+                                                                second_len.to_computed_value(context))
+            },
+            specified::LengthOrPercentageOrKeyword::Keyword(keyword) => {
+                LengthOrPercentageOrKeyword::Keyword(keyword)
+            },
+        }
+    }
+    #[inline]
+    fn from_computed_value(computed: &LengthOrPercentageOrKeyword) -> Self {
+        match *computed {
+            LengthOrPercentageOrKeyword::LengthOrPercentage(first_len, second_len) => {
+                specified::LengthOrPercentageOrKeyword::LengthOrPercentage(
+                    ToComputedValue::from_computed_value(&first_len),
+                    ToComputedValue::from_computed_value(&second_len))
+            },
+            LengthOrPercentageOrKeyword::Keyword(keyword) => {
+                specified::LengthOrPercentageOrKeyword::Keyword(keyword)
+            },
+        }
+    }
+}

components/style/values/computed/mod.rs

@@ -9,13 +9,14 @@ use properties::ComputedValues;
 use std::fmt;
 use super::{CSSFloat, specified};
 use super::LocalToCss;
-use super::specified::AngleOrCorner;
-use url::Url;
 
 pub use cssparser::Color as CSSColor;
+pub use self::image::{EndingShape as GradientShape, Gradient, GradientKind, Image};
+pub use self::image::{LengthOrKeyword, LengthOrPercentageOrKeyword};
 pub use super::specified::{Angle, BorderStyle, Time, UrlExtraData};
 
 pub mod basic_shape;
+pub mod image;
 pub mod position;
 
 pub struct Context<'a> {
@@ -640,175 +641,6 @@ impl ::cssparser::ToCss for LengthOrNone {
     }
 }
 
-impl ToComputedValue for specified::Image {
-    type ComputedValue = Image;
-
-    #[inline]
-    fn to_computed_value(&self, context: &Context) -> Image {
-        match *self {
-            specified::Image::Url(ref url, ref extra_data) => {
-                Image::Url(url.clone(), extra_data.clone())
-            },
-            specified::Image::LinearGradient(ref linear_gradient) => {
-                Image::LinearGradient(linear_gradient.to_computed_value(context))
-            }
-        }
-    }
-
-    #[inline]
-    fn from_computed_value(computed: &Image) -> Self {
-        match *computed {
-            Image::Url(ref url, ref extra_data) => {
-                specified::Image::Url(url.clone(), extra_data.clone())
-            },
-            Image::LinearGradient(ref linear_gradient) => {
-                specified::Image::LinearGradient(
-                    ToComputedValue::from_computed_value(linear_gradient)
-                )
-            }
-        }
-    }
-}
-
-
-/// Computed values for an image according to CSS-IMAGES.
-#[derive(Clone, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-pub enum Image {
-    Url(Url, UrlExtraData),
-    LinearGradient(LinearGradient),
-}
-
-impl fmt::Debug for Image {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match *self {
-            Image::Url(ref url, ref _extra_data) => write!(f, "url(\"{}\")", url),
-            Image::LinearGradient(ref grad) => write!(f, "linear-gradient({:?})", grad),
-        }
-    }
-}
-
-impl ::cssparser::ToCss for Image {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        use values::LocalToCss;
-        match *self {
-            Image::Url(ref url, _) => {
-                url.to_css(dest)
-            }
-            Image::LinearGradient(ref gradient) => gradient.to_css(dest)
-        }
-    }
-}
-
-/// Computed values for a CSS linear gradient.
-#[derive(Clone, PartialEq)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-pub struct LinearGradient {
-    /// The angle or corner of the gradient.
-    pub angle_or_corner: AngleOrCorner,
-
-    /// The color stops.
-    pub stops: Vec<ColorStop>,
-}
-
-impl ::cssparser::ToCss for LinearGradient {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        try!(dest.write_str("linear-gradient("));
-        try!(self.angle_or_corner.to_css(dest));
-        for stop in &self.stops {
-            try!(dest.write_str(", "));
-            try!(stop.to_css(dest));
-        }
-        try!(dest.write_str(")"));
-        Ok(())
-    }
-}
-
-impl fmt::Debug for LinearGradient {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let _ = write!(f, "{:?}", self.angle_or_corner);
-        for stop in &self.stops {
-            let _ = write!(f, ", {:?}", stop);
-        }
-        Ok(())
-    }
-}
-
-/// Computed values for one color stop in a linear gradient.
-#[derive(Clone, PartialEq, Copy)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-pub struct ColorStop {
-    /// The color of this stop.
-    pub color: CSSColor,
-
-    /// The position of this stop. If not specified, this stop is placed halfway between the
-    /// point that precedes it and the point that follows it per CSS-IMAGES § 3.4.
-    pub position: Option<LengthOrPercentage>,
-}
-
-impl ::cssparser::ToCss for ColorStop {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        try!(self.color.to_css(dest));
-        if let Some(position) = self.position {
-            try!(dest.write_str(" "));
-            try!(position.to_css(dest));
-        }
-        Ok(())
-    }
-}
-
-impl fmt::Debug for ColorStop {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let _ = write!(f, "{:?}", self.color);
-        self.position.map(|pos| {
-            let _ = write!(f, " {:?}", pos);
-        });
-        Ok(())
-    }
-}
-
-impl ToComputedValue for specified::LinearGradient {
-    type ComputedValue = LinearGradient;
-
-    #[inline]
-    fn to_computed_value(&self, context: &Context) -> LinearGradient {
-        let specified::LinearGradient {
-            angle_or_corner,
-            ref stops
-        } = *self;
-        LinearGradient {
-            angle_or_corner: angle_or_corner,
-            stops: stops.iter().map(|stop| {
-                ColorStop {
-                    color: stop.color.parsed,
-                    position: match stop.position {
-                        None => None,
-                        Some(value) => Some(value.to_computed_value(context)),
-                    },
-                }
-            }).collect()
-        }
-    }
-    #[inline]
-    fn from_computed_value(computed: &LinearGradient) -> Self {
-        let LinearGradient {
-            angle_or_corner,
-            ref stops
-        } = *computed;
-        specified::LinearGradient {
-            angle_or_corner: angle_or_corner,
-            stops: stops.iter().map(|stop| {
-                specified::ColorStop {
-                    color: ToComputedValue::from_computed_value(&stop.color),
-                    position: match stop.position {
-                        None => None,
-                        Some(value) => Some(ToComputedValue::from_computed_value(&value)),
-                    },
-                }
-            }).collect()
-        }
-    }
-}
 pub type Length = Au;
 pub type Number = CSSFloat;
 pub type Opacity = CSSFloat;

components/style/values/specified/image.rs

@@ -0,0 +1,420 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! CSS handling for the specified value of
+//! [`image`][image]s
+//!
+//! [image]: https://drafts.csswg.org/css-images/#image-values
+
+use cssparser::{Parser, ToCss};
+use parser::{Parse, ParserContext};
+use std::f32::consts::PI;
+use std::fmt;
+use url::Url;
+use values::computed::ComputedValueAsSpecified;
+use values::specified::{Angle, CSSColor, Length, LengthOrPercentage, UrlExtraData};
+use values::specified::position::{Keyword, Position};
+
+/// Specified values for an image according to CSS-IMAGES.
+/// https://drafts.csswg.org/css-images/#image-values
+#[derive(Clone, PartialEq, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum Image {
+    Url(Url, UrlExtraData),
+    Gradient(Gradient),
+}
+
+impl ToCss for Image {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        use values::LocalToCss;
+        match *self {
+            Image::Url(ref url, ref _extra_data) => {
+                url.to_css(dest)
+            }
+            Image::Gradient(ref gradient) => gradient.to_css(dest)
+        }
+    }
+}
+
+impl Image {
+    pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<Image, ()> {
+        if let Ok(url) = input.try(|input| input.expect_url()) {
+            match UrlExtraData::make_from(context) {
+                Some(extra_data) => {
+                    Ok(Image::Url(context.parse_url(&url), extra_data))
+                },
+                None => {
+                    // FIXME(heycam) should ensure we always have a principal, etc., when
+                    // parsing style attributes and re-parsing due to CSS Variables.
+                    println!("stylo: skipping declaration without ParserContextExtraData");
+                    Err(())
+                },
+            }
+        } else {
+            Ok(Image::Gradient(try!(Gradient::parse_function(input))))
+        }
+    }
+}
+
+/// Specified values for a CSS gradient.
+/// https://drafts.csswg.org/css-images/#gradients
+#[derive(Clone, PartialEq, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub struct Gradient {
+    /// The color stops.
+    pub stops: Vec<ColorStop>,
+    /// True if this is a repeating gradient.
+    pub repeating: bool,
+    /// Gradients can be linear or radial.
+    pub gradient_kind: GradientKind,
+}
+
+impl ToCss for Gradient {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        if self.repeating {
+            try!(dest.write_str("repeating-"));
+        }
+        match self.gradient_kind {
+            GradientKind::Linear(angle_or_corner) => {
+                try!(dest.write_str("linear-gradient("));
+                try!(angle_or_corner.to_css(dest));
+            },
+            GradientKind::Radial(ref shape, position) => {
+                try!(dest.write_str("radial-gradient("));
+                try!(shape.to_css(dest));
+                try!(dest.write_str(" at "));
+                try!(position.to_css(dest));
+            },
+        }
+        for stop in &self.stops {
+            try!(dest.write_str(", "));
+            try!(stop.to_css(dest));
+        }
+        dest.write_str(")")
+    }
+}
+
+impl Gradient {
+    /// Parses a gradient from the given arguments.
+    pub fn parse_function(input: &mut Parser) -> Result<Gradient, ()> {
+        let mut repeating = false;
+        let (gradient_kind, stops) = match_ignore_ascii_case! { try!(input.expect_function()),
+            "linear-gradient" => {
+                try!(input.parse_nested_block(|input| {
+                        let kind = try!(GradientKind::parse_linear(input));
+                        let stops = try!(input.parse_comma_separated(ColorStop::parse));
+                        Ok((kind, stops))
+                    })
+                )
+            },
+            "repeating-linear-gradient" => {
+                repeating = true;
+                try!(input.parse_nested_block(|input| {
+                        let kind = try!(GradientKind::parse_linear(input));
+                        let stops = try!(input.parse_comma_separated(ColorStop::parse));
+                        Ok((kind, stops))
+                    })
+                )
+            },
+            "radial-gradient" => {
+                try!(input.parse_nested_block(|input| {
+                        let kind = try!(GradientKind::parse_radial(input));
+                        let stops = try!(input.parse_comma_separated(ColorStop::parse));
+                        Ok((kind, stops))
+                    })
+                )
+            },
+            "repeating-radial-gradient" => {
+                repeating = true;
+                try!(input.parse_nested_block(|input| {
+                        let kind = try!(GradientKind::parse_radial(input));
+                        let stops = try!(input.parse_comma_separated(ColorStop::parse));
+                        Ok((kind, stops))
+                    })
+                )
+            },
+            _ => { return Err(()); }
+        };
+
+        Ok(Gradient {
+            stops: stops,
+            repeating: repeating,
+            gradient_kind: gradient_kind,
+        })
+    }
+}
+
+/// Specified values for CSS linear or radial gradients.
+/// https://drafts.csswg.org/css-images/#gradients
+#[derive(Clone, PartialEq, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum GradientKind {
+    Linear(AngleOrCorner),
+    Radial(EndingShape, Position),
+}
+
+impl GradientKind {
+    /// Parses a linear gradient kind from the given arguments.
+    pub fn parse_linear(input: &mut Parser) -> Result<GradientKind, ()> {
+        let angle_or_corner = try!(AngleOrCorner::parse(input));
+        Ok(GradientKind::Linear(angle_or_corner))
+    }
+
+    /// Parses a radial gradient from the given arguments.
+    pub fn parse_radial(input: &mut Parser) -> Result<GradientKind, ()> {
+        let mut needs_comma = false;
+        let shape = if let Ok(shape) = EndingShape::parse(input) {
+            needs_comma = true;
+            shape
+        } else {
+            EndingShape::Circle(LengthOrKeyword::Keyword(SizeKeyword::FarthestSide))
+        };
+
+        let position = if input.try(|input| input.expect_ident_matching("at")).is_ok() {
+            needs_comma = true;
+            try!(Position::parse(input))
+        } else {
+            Position {
+                horiz_keyword: Some(Keyword::Center),
+                horiz_position: None,
+                vert_keyword: Some(Keyword::Center),
+                vert_position: None,
+            }
+        };
+
+        if needs_comma {
+            try!(input.expect_comma());
+        }
+
+        Ok(GradientKind::Radial(shape, position))
+    }
+}
+
+/// Specified values for an angle or a corner in a linear gradient.
+#[derive(Clone, PartialEq, Copy, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum AngleOrCorner {
+    Angle(Angle),
+    Corner(HorizontalDirection, VerticalDirection),
+}
+
+impl ToCss for AngleOrCorner {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            AngleOrCorner::Angle(angle) => angle.to_css(dest),
+            AngleOrCorner::Corner(horizontal, vertical) => {
+                try!(dest.write_str("to "));
+                try!(horizontal.to_css(dest));
+                try!(dest.write_str(" "));
+                try!(vertical.to_css(dest));
+                Ok(())
+            }
+        }
+    }
+}
+
+impl Parse for AngleOrCorner {
+    fn parse(input: &mut Parser) -> Result<Self, ()> {
+        if input.try(|input| input.expect_ident_matching("to")).is_ok() {
+            let (horizontal, vertical) =
+            if let Ok(value) = input.try(HorizontalDirection::parse) {
+                (Some(value), input.try(VerticalDirection::parse).ok())
+            } else {
+                let value = try!(VerticalDirection::parse(input));
+                (input.try(HorizontalDirection::parse).ok(), Some(value))
+            };
+            try!(input.expect_comma());
+            match (horizontal, vertical) {
+                (None, Some(VerticalDirection::Top)) => {
+                    Ok(AngleOrCorner::Angle(Angle(0.0)))
+                },
+                (Some(HorizontalDirection::Right), None) => {
+                    Ok(AngleOrCorner::Angle(Angle(PI * 0.5)))
+                },
+                (None, Some(VerticalDirection::Bottom)) => {
+                    Ok(AngleOrCorner::Angle(Angle(PI)))
+                },
+                (Some(HorizontalDirection::Left), None) => {
+                    Ok(AngleOrCorner::Angle(Angle(PI * 1.5)))
+                },
+                (Some(horizontal), Some(vertical)) => {
+                    Ok(AngleOrCorner::Corner(horizontal, vertical))
+                }
+                (None, None) => unreachable!(),
+            }
+        } else if let Ok(angle) = input.try(Angle::parse) {
+            try!(input.expect_comma());
+            Ok(AngleOrCorner::Angle(angle))
+        } else {
+            Ok(AngleOrCorner::Angle(Angle(PI)))
+        }
+    }
+}
+
+impl ComputedValueAsSpecified for AngleOrCorner {}
+
+/// Specified values for one color stop in a linear gradient.
+/// https://drafts.csswg.org/css-images/#typedef-color-stop-list
+#[derive(Clone, PartialEq, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub struct ColorStop {
+    /// The color of this stop.
+    pub color: CSSColor,
+
+    /// The position of this stop. If not specified, this stop is placed halfway between the
+    /// point that precedes it and the point that follows it.
+    pub position: Option<LengthOrPercentage>,
+}
+
+impl ToCss for ColorStop {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        try!(self.color.to_css(dest));
+        if let Some(position) = self.position {
+            try!(dest.write_str(" "));
+            try!(position.to_css(dest));
+        }
+        Ok(())
+    }
+}
+
+define_css_keyword_enum!(HorizontalDirection: "left" => Left, "right" => Right);
+define_css_keyword_enum!(VerticalDirection: "top" => Top, "bottom" => Bottom);
+
+impl Parse for ColorStop {
+    fn parse(input: &mut Parser) -> Result<Self, ()> {
+        Ok(ColorStop {
+            color: try!(CSSColor::parse(input)),
+            position: input.try(LengthOrPercentage::parse).ok(),
+        })
+    }
+}
+
+/// Determines whether the gradient's ending shape is a circle or an ellipse.
+/// If <shape> is omitted, the ending shape defaults to a circle
+/// if the <size> is a single <length>, and to an ellipse otherwise.
+/// https://drafts.csswg.org/css-images/#valdef-radial-gradient-ending-shape
+#[derive(Clone, PartialEq, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum EndingShape {
+    Circle(LengthOrKeyword),
+    Ellipse(LengthOrPercentageOrKeyword),
+}
+
+impl Parse for EndingShape {
+    fn parse(input: &mut Parser) -> Result<Self, ()> {
+        // FIXME(#13664): Normally size can come before shape keywords but currently
+        // parsing fails if size comes before shape keyword.
+        match_ignore_ascii_case! { try!(input.expect_ident()),
+            "circle" => {
+                let position = input.try(LengthOrKeyword::parse).unwrap_or(
+                    LengthOrKeyword::Keyword(SizeKeyword::FarthestSide));
+                Ok(EndingShape::Circle(position))
+            },
+            "ellipse" => {
+              let length = input.try(LengthOrPercentageOrKeyword::parse)
+                                .unwrap_or(LengthOrPercentageOrKeyword::Keyword(SizeKeyword::FarthestSide));
+                Ok(EndingShape::Ellipse(length))
+            },
+            _ => {
+                // If two <length> is present, it defaults to ellipse, otherwise defaults to circle.
+                if let Ok(length) = LengthOrPercentageOrKeyword::parse(input) {
+                    if let LengthOrPercentageOrKeyword::Keyword(keyword) = length {
+                        // A single keyword is valid for both ellipse and circle, but we default to circle.
+                        // The grammar for ending shapes for circle and ellipse have overlap so we cannot simply
+                        // try to parse as circle first
+                        Ok(EndingShape::Circle(LengthOrKeyword::Keyword(keyword)))
+                    } else {
+                        Ok(EndingShape::Ellipse(length))
+                    }
+                } else {
+                    // If both shape and size are omitted, we do not parse as an EndingShape
+                    // Instead, GradientKind::parse_radial will go ahead and parse the stops
+                    // This is necessary because GradientKind::parse_radial needs to know
+                    // whether or not to expect a comma
+                    Ok(EndingShape::Circle(try!(input.try(LengthOrKeyword::parse))))
+                }
+            }
+        }
+    }
+}
+
+impl ToCss for EndingShape {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            EndingShape::Circle(ref length) => {
+                try!(dest.write_str("circle "));
+                try!(length.to_css(dest));
+            },
+            EndingShape::Ellipse(ref length) => {
+                try!(dest.write_str("ellipse "));
+                try!(length.to_css(dest));
+            },
+        }
+        Ok(())
+    }
+}
+
+/// https://drafts.csswg.org/css-images/#valdef-radial-gradient-size
+#[derive(Clone, PartialEq, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum LengthOrKeyword {
+    Length(Length),
+    Keyword(SizeKeyword),
+}
+
+impl Parse for LengthOrKeyword {
+    fn parse(input: &mut Parser) -> Result<Self, ()> {
+        if let Ok(keyword) = input.try(SizeKeyword::parse) {
+            Ok(LengthOrKeyword::Keyword(keyword))
+        } else {
+            Ok(LengthOrKeyword::Length(try!(Length::parse(input))))
+        }
+    }
+}
+
+impl ToCss for LengthOrKeyword {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            LengthOrKeyword::Length(ref length) => length.to_css(dest),
+            LengthOrKeyword::Keyword(keyword) => keyword.to_css(dest),
+        }
+    }
+}
+
+/// https://drafts.csswg.org/css-images/#valdef-radial-gradient-size
+#[derive(Clone, PartialEq, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum LengthOrPercentageOrKeyword {
+    LengthOrPercentage(LengthOrPercentage, LengthOrPercentage),
+    Keyword(SizeKeyword),
+}
+
+
+impl Parse for LengthOrPercentageOrKeyword {
+    fn parse(input: &mut Parser) -> Result<Self, ()> {
+        if let Ok(keyword) = input.try(SizeKeyword::parse) {
+            Ok(LengthOrPercentageOrKeyword::Keyword(keyword))
+        } else {
+            Ok(LengthOrPercentageOrKeyword::LengthOrPercentage(try!(LengthOrPercentage::parse(input)),
+                                                               try!(LengthOrPercentage::parse(input))))
+        }
+    }
+}
+
+impl ToCss for LengthOrPercentageOrKeyword {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            LengthOrPercentageOrKeyword::LengthOrPercentage(ref first_len, second_len) => {
+                try!(first_len.to_css(dest));
+                try!(dest.write_str(" "));
+                second_len.to_css(dest)
+            },
+            LengthOrPercentageOrKeyword::Keyword(keyword) => keyword.to_css(dest),
+        }
+    }
+}
+
+/// https://drafts.csswg.org/css-images/#typedef-extent-keyword
+define_css_keyword_enum!(SizeKeyword: "closest-side" => ClosestSide, "farthest-side" => FarthestSide,
+                         "closest-corner" => ClosestCorner, "farthest-corner" => FarthestCorner);

components/style/values/specified/mod.rs

@@ -7,7 +7,7 @@ use cssparser::{self, Parser, ToCss, Token};
 use euclid::size::Size2D;
 #[cfg(feature = "gecko")]
 use gecko_bindings::ptr::{GeckoArcPrincipal, GeckoArcURI};
-use parser::ParserContext;
+use parser::{Parse, ParserContext};
 #[cfg(feature = "gecko")]
 use parser::ParserContextExtraData;
 use std::ascii::AsciiExt;
@@ -18,9 +18,13 @@ use std::ops::Mul;
 use style_traits::values::specified::AllowedNumericType;
 use super::{CSSFloat, FONT_MEDIUM_PX, HasViewportPercentage, LocalToCss, NoViewportPercentage};
 use super::computed::{self, ComputedValueAsSpecified, Context, ToComputedValue};
-use url::Url;
+
+pub use self::image::{AngleOrCorner, ColorStop, EndingShape as GradientEndingShape, Gradient};
+pub use self::image::{GradientKind, HorizontalDirection, Image, LengthOrKeyword, LengthOrPercentageOrKeyword};
+pub use self::image::{SizeKeyword, VerticalDirection};
 
 pub mod basic_shape;
+pub mod image;
 pub mod position;
 
 impl NoViewportPercentage for i32 {}  // For PropertyDeclaration::Order
@@ -299,9 +303,6 @@ impl Length {
             _ => Err(())
         }
     }
-    pub fn parse(input: &mut Parser) -> Result<Length, ()> {
-        Length::parse_internal(input, AllowedNumericType::All)
-    }
     pub fn parse_non_negative(input: &mut Parser) -> Result<Length, ()> {
         Length::parse_internal(input, AllowedNumericType::NonNegative)
     }
@@ -333,6 +334,12 @@ impl Length {
     }
 }
 
+impl Parse for Length {
+    fn parse(input: &mut Parser) -> Result<Self, ()> {
+        Length::parse_internal(input, AllowedNumericType::All)
+    }
+}
+
 #[derive(Clone, Debug)]
 struct CalcSumNode {
     products: Vec<CalcProductNode>,
@@ -908,16 +915,20 @@ impl LengthOrPercentage {
             _ => Err(())
         }
     }
-    #[inline]
-    pub fn parse(input: &mut Parser) -> Result<LengthOrPercentage, ()> {
-        LengthOrPercentage::parse_internal(input, AllowedNumericType::All)
-    }
+
     #[inline]
     pub fn parse_non_negative(input: &mut Parser) -> Result<LengthOrPercentage, ()> {
         LengthOrPercentage::parse_internal(input, AllowedNumericType::NonNegative)
     }
 }
 
+impl Parse for LengthOrPercentage {
+    #[inline]
+    fn parse(input: &mut Parser) -> Result<Self, ()> {
+        LengthOrPercentage::parse_internal(input, AllowedNumericType::All)
+    }
+}
+
 #[derive(Clone, PartialEq, Copy, Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum LengthOrPercentageOrAuto {
@@ -1267,180 +1278,6 @@ impl UrlExtraData {
     }
 }
 
-/// Specified values for an image according to CSS-IMAGES.
-#[derive(Clone, PartialEq, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-pub enum Image {
-    Url(Url, UrlExtraData),
-    LinearGradient(LinearGradient),
-}
-
-impl ToCss for Image {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        use values::LocalToCss;
-        match *self {
-            Image::Url(ref url, ref _extra_data) => {
-                url.to_css(dest)
-            }
-            Image::LinearGradient(ref gradient) => gradient.to_css(dest)
-        }
-    }
-}
-
-impl Image {
-    pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<Image, ()> {
-        if let Ok(url) = input.try(|input| input.expect_url()) {
-            match UrlExtraData::make_from(context) {
-                Some(extra_data) => {
-                    Ok(Image::Url(context.parse_url(&url), extra_data))
-                },
-                None => {
-                    // FIXME(heycam) should ensure we always have a principal, etc., when
-                    // parsing style attributes and re-parsing due to CSS Variables.
-                    println!("stylo: skipping declaration without ParserContextExtraData");
-                    Err(())
-                },
-            }
-        } else {
-            match_ignore_ascii_case! { try!(input.expect_function()),
-                "linear-gradient" => {
-                    Ok(Image::LinearGradient(try!(
-                        input.parse_nested_block(LinearGradient::parse_function))))
-                },
-                _ => Err(())
-            }
-        }
-    }
-}
-
-/// Specified values for a CSS linear gradient.
-#[derive(Clone, PartialEq, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-pub struct LinearGradient {
-    /// The angle or corner of the gradient.
-    pub angle_or_corner: AngleOrCorner,
-
-    /// The color stops.
-    pub stops: Vec<ColorStop>,
-}
-
-impl ToCss for LinearGradient {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        try!(dest.write_str("linear-gradient("));
-        try!(self.angle_or_corner.to_css(dest));
-        for stop in &self.stops {
-            try!(dest.write_str(", "));
-            try!(stop.to_css(dest));
-        }
-        try!(dest.write_str(")"));
-        Ok(())
-    }
-}
-
-/// Specified values for an angle or a corner in a linear gradient.
-#[derive(Clone, PartialEq, Copy, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-pub enum AngleOrCorner {
-    Angle(Angle),
-    Corner(HorizontalDirection, VerticalDirection),
-}
-
-impl ToCss for AngleOrCorner {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        match *self {
-            AngleOrCorner::Angle(angle) => angle.to_css(dest),
-            AngleOrCorner::Corner(horizontal, vertical) => {
-                try!(dest.write_str("to "));
-                try!(horizontal.to_css(dest));
-                try!(dest.write_str(" "));
-                try!(vertical.to_css(dest));
-                Ok(())
-            }
-        }
-    }
-}
-
-/// Specified values for one color stop in a linear gradient.
-#[derive(Clone, PartialEq, Debug)]
-#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-pub struct ColorStop {
-    /// The color of this stop.
-    pub color: CSSColor,
-
-    /// The position of this stop. If not specified, this stop is placed halfway between the
-    /// point that precedes it and the point that follows it.
-    pub position: Option<LengthOrPercentage>,
-}
-
-impl ToCss for ColorStop {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
-        try!(self.color.to_css(dest));
-        if let Some(position) = self.position {
-            try!(dest.write_str(" "));
-            try!(position.to_css(dest));
-        }
-        Ok(())
-    }
-}
-
-define_css_keyword_enum!(HorizontalDirection: "left" => Left, "right" => Right);
-define_css_keyword_enum!(VerticalDirection: "top" => Top, "bottom" => Bottom);
-
-fn parse_one_color_stop(input: &mut Parser) -> Result<ColorStop, ()> {
-    Ok(ColorStop {
-        color: try!(CSSColor::parse(input)),
-        position: input.try(LengthOrPercentage::parse).ok(),
-    })
-}
-
-impl LinearGradient {
-    /// Parses a linear gradient from the given arguments.
-    pub fn parse_function(input: &mut Parser) -> Result<LinearGradient, ()> {
-        let angle_or_corner = if input.try(|input| input.expect_ident_matching("to")).is_ok() {
-            let (horizontal, vertical) =
-            if let Ok(value) = input.try(HorizontalDirection::parse) {
-                (Some(value), input.try(VerticalDirection::parse).ok())
-            } else {
-                let value = try!(VerticalDirection::parse(input));
-                (input.try(HorizontalDirection::parse).ok(), Some(value))
-            };
-            try!(input.expect_comma());
-            match (horizontal, vertical) {
-                (None, Some(VerticalDirection::Top)) => {
-                    AngleOrCorner::Angle(Angle(0.0))
-                },
-                (Some(HorizontalDirection::Right), None) => {
-                    AngleOrCorner::Angle(Angle(PI * 0.5))
-                },
-                (None, Some(VerticalDirection::Bottom)) => {
-                    AngleOrCorner::Angle(Angle(PI))
-                },
-                (Some(HorizontalDirection::Left), None) => {
-                    AngleOrCorner::Angle(Angle(PI * 1.5))
-                },
-                (Some(horizontal), Some(vertical)) => {
-                    AngleOrCorner::Corner(horizontal, vertical)
-                }
-                (None, None) => unreachable!(),
-            }
-        } else if let Ok(angle) = input.try(Angle::parse) {
-            try!(input.expect_comma());
-            AngleOrCorner::Angle(angle)
-        } else {
-            AngleOrCorner::Angle(Angle(PI))
-        };
-        // Parse the color stops.
-        let stops = try!(input.parse_comma_separated(parse_one_color_stop));
-        if stops.len() < 2 {
-            return Err(())
-        }
-        Ok(LinearGradient {
-            angle_or_corner: angle_or_corner,
-            stops: stops,
-        })
-    }
-}
-
 pub fn parse_border_radius(input: &mut Parser) -> Result<BorderRadiusSize, ()> {
     input.try(BorderRadiusSize::parse).or_else(|()| {
             match_ignore_ascii_case! { try!(input.expect_ident()),

components/style/values/specified/position.rs

@@ -8,6 +8,7 @@
 //! [position]: https://drafts.csswg.org/css-backgrounds-3/#position
 
 use cssparser::{Parser, ToCss, Token};
+use parser::Parse;
 use std::fmt;
 use values::HasViewportPercentage;
 use values::computed::{CalcLengthOrPercentage, Context};