Auto merge of #14598 - DominoTree:master, r=canaltinova

Fix linear gradient's specified form #13892

<!-- Please describe your changes on the following line: -->
WIP for #13892

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #13892  (github issue number if applicable).

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- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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components/layout/display_list_builder.rs

@@ -54,8 +54,8 @@ use style::properties::{self, ServoComputedValues};
 use style::properties::style_structs;
 use style::servo::restyle_damage::REPAINT;
 use style::values::{self, Either, RGBA, computed};
-use style::values::computed::{Gradient, GradientKind, LengthOrPercentage, LengthOrPercentageOrAuto};
+use style::values::computed::{AngleOrCorner, Gradient, GradientKind, LengthOrPercentage, LengthOrPercentageOrAuto};
-use style::values::specified::{AngleOrCorner, HorizontalDirection, VerticalDirection};
+use style::values::specified::{HorizontalDirection, VerticalDirection};
 use style_traits::cursor::Cursor;
 use table_cell::CollapsedBordersForCell;
 use webrender_traits::{ColorF, GradientStop};

components/style/gecko/conversions.rs

@@ -160,10 +160,9 @@ impl nsStyleImage {
         use gecko_bindings::structs::{NS_STYLE_GRADIENT_SIZE_CLOSEST_SIDE, NS_STYLE_GRADIENT_SIZE_EXPLICIT_SIZE};
         use gecko_bindings::structs::{NS_STYLE_GRADIENT_SIZE_FARTHEST_CORNER, NS_STYLE_GRADIENT_SIZE_FARTHEST_SIDE};
         use gecko_bindings::structs::nsStyleCoord;
-        use values::computed::{GradientKind, GradientShape, LengthOrKeyword};
+        use values::computed::{AngleOrCorner, GradientKind, GradientShape, LengthOrKeyword};
         use values::computed::LengthOrPercentageOrKeyword;
-        use values::specified::{AngleOrCorner, HorizontalDirection};
+        use values::specified::{HorizontalDirection, SizeKeyword, VerticalDirection};
-        use values::specified::{SizeKeyword, VerticalDirection};
 
         let stop_count = gradient.stops.len();
         if stop_count >= ::std::u32::MAX as usize {

components/style/values/computed/image.rs

@@ -8,11 +8,12 @@
 //! [image]: https://drafts.csswg.org/css-images/#image-values
 
 use cssparser::Color as CSSColor;
+use std::f32::consts::PI;
 use std::fmt;
 use style_traits::ToCss;
-use values::computed::{Context, Length, LengthOrPercentage, ToComputedValue};
+use values::computed::{Angle, Context, Length, LengthOrPercentage, ToComputedValue};
 use values::computed::position::Position;
-use values::specified::{self, AngleOrCorner, SizeKeyword};
+use values::specified::{self, HorizontalDirection, SizeKeyword, VerticalDirection};
 use values::specified::url::SpecifiedUrl;
 
 
@@ -185,7 +186,7 @@ impl ToComputedValue for specified::GradientKind {
     fn to_computed_value(&self, context: &Context) -> GradientKind {
         match *self {
             specified::GradientKind::Linear(angle_or_corner) => {
-                GradientKind::Linear(angle_or_corner)
+                GradientKind::Linear(angle_or_corner.to_computed_value(context))
             },
             specified::GradientKind::Radial(ref shape, position) => {
                 GradientKind::Radial(shape.to_computed_value(context),
@@ -454,3 +455,75 @@ impl ToComputedValue for specified::LengthOrPercentageOrKeyword {
         }
     }
 }
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum AngleOrCorner {
+    Angle(Angle),
+    Corner(HorizontalDirection, VerticalDirection)
+}
+
+impl ToComputedValue for specified::AngleOrCorner {
+    type ComputedValue = AngleOrCorner;
+
+    #[inline]
+    fn to_computed_value(&self, _: &Context) -> AngleOrCorner {
+        match *self {
+            specified::AngleOrCorner::None => {
+                AngleOrCorner::Angle(Angle(0.0))
+            },
+            specified::AngleOrCorner::Angle(angle) => {
+                AngleOrCorner::Angle(angle)
+            },
+            specified::AngleOrCorner::Corner(horizontal, vertical) => {
+                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!()
+                    }
+                }
+            }
+        }
+    }
+
+    #[inline]
+    fn from_computed_value(computed: &AngleOrCorner) -> Self {
+        match *computed {
+            AngleOrCorner::Angle(angle) => {
+                specified::AngleOrCorner::Angle(angle)
+            },
+            AngleOrCorner::Corner(horizontal, vertical) => {
+                specified::AngleOrCorner::Corner(Some(horizontal), Some(vertical))
+            }
+        }
+    }
+}
+
+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(())
+            }
+        }
+    }
+}

components/style/values/computed/mod.rs

@@ -11,7 +11,7 @@ use style_traits::ToCss;
 use super::{CSSFloat, specified};
 
 pub use cssparser::Color as CSSColor;
-pub use self::image::{EndingShape as GradientShape, Gradient, GradientKind, Image};
+pub use self::image::{AngleOrCorner, EndingShape as GradientShape, Gradient, GradientKind, Image};
 pub use self::image::{LengthOrKeyword, LengthOrPercentageOrKeyword};
 pub use super::{Either, None_};
 pub use super::specified::{Angle, BorderStyle, GridLine, Time, UrlOrNone};

components/style/values/specified/image.rs

@@ -10,10 +10,8 @@
 use cssparser::Parser;
 use parser::{Parse, ParserContext};
 use servo_url::ServoUrl;
-use std::f32::consts::PI;
 use std::fmt;
 use style_traits::ToCss;
-use values::computed::ComputedValueAsSpecified;
 use values::specified::{Angle, CSSColor, Length, LengthOrPercentage};
 use values::specified::position::Position;
 use values::specified::url::{SpecifiedUrl, UrlExtraData};
@@ -70,10 +68,14 @@ impl ToCss for Gradient {
         if self.repeating {
             try!(dest.write_str("repeating-"));
         }
+        let mut skipcomma = false;
         match self.gradient_kind {
             GradientKind::Linear(angle_or_corner) => {
                 try!(dest.write_str("linear-gradient("));
                 try!(angle_or_corner.to_css(dest));
+                if angle_or_corner == AngleOrCorner::None {
+                    skipcomma = true;
+                }
             },
             GradientKind::Radial(ref shape, position) => {
                 try!(dest.write_str("radial-gradient("));
@@ -83,7 +85,11 @@ impl ToCss for Gradient {
             },
         }
         for stop in &self.stops {
-            try!(dest.write_str(", "));
+            if !skipcomma {
+                try!(dest.write_str(", "));
+            } else {
+                skipcomma = false;
+            }
             try!(stop.to_css(dest));
         }
         dest.write_str(")")
@@ -230,18 +236,28 @@ fn parse_position(context: &ParserContext, input: &mut Parser) -> Result<Positio
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum AngleOrCorner {
     Angle(Angle),
-    Corner(HorizontalDirection, VerticalDirection),
+    Corner(Option<HorizontalDirection>, Option<VerticalDirection>),
+    None,
 }
 
 impl ToCss for AngleOrCorner {
     fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
         match *self {
+            AngleOrCorner::None => Ok(()),
             AngleOrCorner::Angle(angle) => angle.to_css(dest),
             AngleOrCorner::Corner(horizontal, vertical) => {
                 try!(dest.write_str("to "));
-                try!(horizontal.to_css(dest));
+                let mut horizontal_present = false;
-                try!(dest.write_str(" "));
+                if let Some(horizontal) = horizontal {
-                try!(vertical.to_css(dest));
+                    try!(horizontal.to_css(dest));
+                    horizontal_present = true;
+                }
+                if let Some(vertical) = vertical {
+                    if horizontal_present {
+                        try!(dest.write_str(" "));
+                    }
+                    try!(vertical.to_css(dest));
+                }
                 Ok(())
             }
         }
@@ -259,35 +275,16 @@ impl Parse for AngleOrCorner {
                 (input.try(HorizontalDirection::parse).ok(), Some(value))
             };
             try!(input.expect_comma());
-            match (horizontal, vertical) {
+            Ok(AngleOrCorner::Corner(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(|i| Angle::parse(context, i)) {
             try!(input.expect_comma());
             Ok(AngleOrCorner::Angle(angle))
         } else {
-            Ok(AngleOrCorner::Angle(Angle(PI)))
+            Ok(AngleOrCorner::None)
         }
     }
 }
 
-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)]

tests/unit/style/parsing/image.rs

@@ -12,12 +12,10 @@ use style_traits::ToCss;
 #[test]
 fn test_linear_gradient() {
     // Parsing from the right
-    assert_roundtrip_with_context!(Image::parse, "linear-gradient(to left, red, green)",
+    assert_roundtrip_with_context!(Image::parse, "linear-gradient(to left, red, green)");
-                                                 "linear-gradient(4.712389rad, red, green)");
 
     // Parsing from the left
-    assert_roundtrip_with_context!(Image::parse, "linear-gradient(to right, red, green)",
+    assert_roundtrip_with_context!(Image::parse, "linear-gradient(to right, red, green)");
-                                                 "linear-gradient(1.5707964rad, red, green)");
 
     // Parsing with two values for <side-or-corner>
     assert_roundtrip_with_context!(Image::parse, "linear-gradient(to right top, red, green)");
@@ -26,17 +24,14 @@ fn test_linear_gradient() {
     assert_roundtrip_with_context!(Image::parse, "linear-gradient(45deg, red, green)",
                                                  "linear-gradient(0.7853982rad, red, green)");
 
-   // Parsing with more than two entries in <color-stop-list>
+    // Parsing with more than two entries in <color-stop-list>
-   assert_roundtrip_with_context!(Image::parse, "linear-gradient(red, yellow, green)",
+    assert_roundtrip_with_context!(Image::parse, "linear-gradient(red, yellow, green)");
-                                                "linear-gradient(3.1415927rad, red, yellow, green)");
 
-   // Parsing with percentage in the <color-stop-list>
+    // Parsing with percentage in the <color-stop-list>
-   assert_roundtrip_with_context!(Image::parse, "linear-gradient(red, green, yellow 50%)",
+    assert_roundtrip_with_context!(Image::parse, "linear-gradient(red, green, yellow 50%)");
-                                                "linear-gradient(3.1415927rad, red, green, yellow 50%)");
 
     // Parsing without <angle> and <side-or-corner>
-    assert_roundtrip_with_context!(Image::parse, "linear-gradient(red, green)",
+    assert_roundtrip_with_context!(Image::parse, "linear-gradient(red, green)");
-                                                 "linear-gradient(3.1415927rad, red, green)");
 }
 
 #[test]