style: Merge ImageLayer and Image.

ImageLayer is almost the only usage of Image, so keeping them in the same enum
makes the resulting C++ struct smaller, and makes it map more cleanly to
nsStyleImage.

Differential Revision: https://phabricator.services.mozilla.com/D62161

components/style/values/computed/image.rs

@@ -22,9 +22,6 @@ use std::f32::consts::PI;
 use std::fmt::{self, Write};
 use style_traits::{CssWriter, ToCss};
 
-/// A computed image layer.
-pub type ImageLayer = generic::GenericImageLayer<Image>;
-
 /// Computed values for an image according to CSS-IMAGES.
 /// <https://drafts.csswg.org/css-images/#image-values>
 pub type Image = generic::GenericImage<Gradient, MozImageRect, ComputedImageUrl>;
@@ -65,7 +62,7 @@ pub type ColorStop = generic::ColorStop<Color, LengthPercentage>;
 
 /// Computed values for `-moz-image-rect(...)`.
 #[cfg(feature = "gecko")]
-pub type MozImageRect = generic::MozImageRect<NumberOrPercentage, ComputedImageUrl>;
+pub type MozImageRect = generic::GenericMozImageRect<NumberOrPercentage, ComputedImageUrl>;
 
 /// Empty enum on non-gecko
 #[cfg(not(feature = "gecko"))]

components/style/values/computed/mod.rs

@@ -57,7 +57,7 @@ pub use self::font::{FontSize, FontSizeAdjust, FontStretch, FontSynthesis};
 pub use self::font::{FontVariantAlternates, FontWeight};
 pub use self::font::{FontVariantEastAsian, FontVariationSettings};
 pub use self::font::{MozScriptLevel, MozScriptMinSize, MozScriptSizeMultiplier, XLang, XTextZoom};
-pub use self::image::{Gradient, GradientItem, Image, ImageLayer, LineDirection, MozImageRect};
+pub use self::image::{Gradient, GradientItem, Image, LineDirection, MozImageRect};
 pub use self::length::{CSSPixelLength, ExtremumLength, NonNegativeLength};
 pub use self::length::{Length, LengthOrNumber, LengthPercentage, NonNegativeLengthOrNumber};
 pub use self::length::{LengthOrAuto, LengthPercentageOrAuto, MaxSize, Size};

components/style/values/generics/image.rs

@@ -13,51 +13,22 @@ use servo_arc::Arc;
 use std::fmt::{self, Write};
 use style_traits::{CssWriter, ToCss};
 
-/// An <image> | <none> (for background-image, for example).
-#[derive(
-    Clone,
-    Debug,
-    MallocSizeOf,
-    Parse,
-    PartialEq,
-    SpecifiedValueInfo,
-    ToComputedValue,
-    ToCss,
-    ToResolvedValue,
-    ToShmem,
-)]
-pub enum GenericImageLayer<Image> {
-    /// The `none` value.
-    None,
-    /// The `<image>` value.
-    Image(Image),
-}
-
-pub use self::GenericImageLayer as ImageLayer;
-
-impl<I> ImageLayer<I> {
-    /// Returns `none`.
-    #[inline]
-    pub fn none() -> Self {
-        ImageLayer::None
-    }
-}
-
-/// An [image].
+/// An `<image> | none` value.
 ///
-/// [image]: https://drafts.csswg.org/css-images/#image-values
+/// https://drafts.csswg.org/css-images/#image-values
 #[derive(
     Clone, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToComputedValue, ToResolvedValue, ToShmem,
 )]
 #[repr(C, u8)]
-pub enum GenericImage<Gradient, MozImageRect, ImageUrl> {
+pub enum GenericImage<G, MozImageRect, ImageUrl> {
+    /// `none` variant.
+    None,
     /// A `<url()>` image.
     Url(ImageUrl),
 
     /// A `<gradient>` image.  Gradients are rather large, and not nearly as
     /// common as urls, so we box them here to keep the size of this enum sane.
-    Gradient(Box<Gradient>),
-
+    Gradient(Box<G>),
     /// A `-moz-image-rect` image.  Also fairly large and rare.
     // not cfg’ed out on non-Gecko to avoid `error[E0392]: parameter `MozImageRect` is never used`
     // Instead we make MozImageRect an empty enum
@@ -285,7 +256,7 @@ impl ToCss for PaintWorklet {
 ///
 /// `-moz-image-rect(<uri>, top, right, bottom, left);`
 #[allow(missing_docs)]
-#[css(comma, function)]
+#[css(comma, function = "-moz-image-rect")]
 #[derive(
     Clone,
     Debug,
@@ -297,7 +268,8 @@ impl ToCss for PaintWorklet {
     ToResolvedValue,
     ToShmem,
 )]
-pub struct MozImageRect<NumberOrPercentage, MozImageRectUrl> {
+#[repr(C)]
+pub struct GenericMozImageRect<NumberOrPercentage, MozImageRectUrl> {
     pub url: MozImageRectUrl,
     pub top: NumberOrPercentage,
     pub right: NumberOrPercentage,
@@ -305,6 +277,8 @@ pub struct MozImageRect<NumberOrPercentage, MozImageRectUrl> {
     pub left: NumberOrPercentage,
 }
 
+pub use self::GenericMozImageRect as MozImageRect;
+
 impl<G, R, U> fmt::Debug for Image<G, R, U>
 where
     G: ToCss,
@@ -327,6 +301,7 @@ where
         W: Write,
     {
         match *self {
+            Image::None => dest.write_str("none"),
             Image::Url(ref url) => url.to_css(dest),
             Image::Gradient(ref gradient) => gradient.to_css(dest),
             Image::Rect(ref rect) => rect.to_css(dest),

components/style/values/specified/basic_shape.rs

@@ -71,6 +71,10 @@ impl Parse for ClippingShape {
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
     ) -> Result<Self, ParseError<'i>> {
+        if input.try(|i| i.expect_ident_matching("none")).is_ok() {
+            return Ok(ShapeSource::None);
+        }
+
         if is_clip_path_path_enabled(context) {
             if let Ok(p) = input.try(|i| Path::parse(context, i)) {
                 return Ok(ShapeSource::Path(p));
@@ -91,7 +95,14 @@ impl Parse for FloatAreaShape {
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
     ) -> Result<Self, ParseError<'i>> {
+        // Need to parse this here so that `Image::parse_with_cors_anonymous`
+        // doesn't parse it.
+        if input.try(|i| i.expect_ident_matching("none")).is_ok() {
+            return Ok(ShapeSource::None);
+        }
+
         if let Ok(image) = input.try(|i| Image::parse_with_cors_anonymous(context, i)) {
+            debug_assert_ne!(image, Image::None);
             return Ok(ShapeSource::ImageOrUrl(image));
         }
 
@@ -108,10 +119,6 @@ where
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
     ) -> Result<Self, ParseError<'i>> {
-        if input.try(|i| i.expect_ident_matching("none")).is_ok() {
-            return Ok(ShapeSource::None);
-        }
-
         fn parse_component<U: Parse>(
             context: &ParserContext,
             input: &mut Parser,

components/style/values/specified/image.rs

@@ -32,24 +32,6 @@ use std::fmt::{self, Write};
 use style_traits::{CssType, CssWriter, KeywordsCollectFn, ParseError};
 use style_traits::{SpecifiedValueInfo, StyleParseErrorKind, ToCss};
 
-/// A specified image layer.
-pub type ImageLayer = generic::GenericImageLayer<Image>;
-
-impl ImageLayer {
-    /// This is a specialization of Either with an alternative parse
-    /// method to provide anonymous CORS headers for the Image url fetch.
-    pub fn parse_with_cors_anonymous<'i, 't>(
-        context: &ParserContext,
-        input: &mut Parser<'i, 't>,
-    ) -> Result<Self, ParseError<'i>> {
-        if let Ok(v) = input.try(|i| Image::parse_with_cors_anonymous(context, i)) {
-            return Ok(generic::GenericImageLayer::Image(v));
-        }
-        input.expect_ident_matching("none")?;
-        Ok(generic::GenericImageLayer::None)
-    }
-}
-
 /// Specified values for an image according to CSS-IMAGES.
 /// <https://drafts.csswg.org/css-images/#image-values>
 pub type Image = generic::Image<Gradient, MozImageRect, SpecifiedImageUrl>;
@@ -118,8 +100,8 @@ pub type ColorStop = generic::ColorStop<Color, LengthPercentage>;
 
 /// Specified values for `moz-image-rect`
 /// -moz-image-rect(<uri>, top, right, bottom, left);
-#[cfg(feature = "gecko")]
-pub type MozImageRect = generic::MozImageRect<NumberOrPercentage, SpecifiedImageUrl>;
+#[cfg(all(feature = "gecko", not(feature = "cbindgen")))]
+pub type MozImageRect = generic::GenericMozImageRect<NumberOrPercentage, SpecifiedImageUrl>;
 
 #[cfg(not(feature = "gecko"))]
 #[derive(
@@ -141,6 +123,9 @@ impl Parse for Image {
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
     ) -> Result<Image, ParseError<'i>> {
+        if input.try(|i| i.expect_ident_matching("none")).is_ok() {
+            return Ok(generic::Image::None);
+        }
         if let Ok(url) = input.try(|input| SpecifiedImageUrl::parse(context, input)) {
             return Ok(generic::Image::Url(url));
         }

components/style/values/specified/mod.rs

@@ -56,7 +56,7 @@ pub use self::font::{FontVariantAlternates, FontWeight};
 pub use self::font::{FontVariantEastAsian, FontVariationSettings};
 pub use self::font::{MozScriptLevel, MozScriptMinSize, MozScriptSizeMultiplier, XLang, XTextZoom};
 pub use self::image::{ColorStop, EndingShape as GradientEndingShape, Gradient};
-pub use self::image::{GradientItem, GradientKind, Image, ImageLayer, MozImageRect};
+pub use self::image::{GradientItem, GradientKind, Image, MozImageRect};
 pub use self::length::{AbsoluteLength, CalcLengthPercentage, CharacterWidth};
 pub use self::length::{FontRelativeLength, Length, LengthOrNumber, NonNegativeLengthOrNumber};
 pub use self::length::{LengthOrAuto, LengthPercentage, LengthPercentageOrAuto};