style: Support image-set() on the cursor property

Differential Revision: https://phabricator.services.mozilla.com/D106745

components/style/values/computed/ui.rs

@@ -5,7 +5,7 @@
 //! Computed values for UI properties
 
 use crate::values::computed::color::Color;
-use crate::values::computed::url::ComputedImageUrl;
+use crate::values::computed::image::Image;
 use crate::values::computed::Number;
 use crate::values::generics::ui as generics;
 
@@ -16,7 +16,7 @@ pub use crate::values::specified::ui::{MozForceBrokenImageIcon, UserSelect};
 pub type Cursor = generics::GenericCursor<CursorImage>;
 
 /// A computed value for item of `image cursors`.
-pub type CursorImage = generics::GenericCursorImage<ComputedImageUrl, Number>;
+pub type CursorImage = generics::GenericCursorImage<Image, Number>;
 
 /// A computed value for `scrollbar-color` property.
 pub type ScrollbarColor = generics::GenericScrollbarColor<Color>;

components/style/values/generics/ui.rs

@@ -61,15 +61,14 @@ impl<Image: ToCss> ToCss for Cursor<Image> {
     Debug,
     MallocSizeOf,
     PartialEq,
-    SpecifiedValueInfo,
     ToComputedValue,
     ToResolvedValue,
     ToShmem,
 )]
 #[repr(C)]
-pub struct GenericCursorImage<ImageUrl, Number> {
+pub struct GenericCursorImage<Image, Number> {
     /// The url to parse images from.
-    pub url: ImageUrl,
+    pub image: Image,
     /// Whether the image has a hotspot or not.
     pub has_hotspot: bool,
     /// The x coordinate.
@@ -80,12 +79,12 @@ pub struct GenericCursorImage<ImageUrl, Number> {
 
 pub use self::GenericCursorImage as CursorImage;
 
-impl<ImageUrl: ToCss, Number: ToCss> ToCss for CursorImage<ImageUrl, Number> {
+impl<Image: ToCss, Number: ToCss> ToCss for CursorImage<Image, Number> {
     fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
     where
         W: Write,
     {
-        self.url.to_css(dest)?;
+        self.image.to_css(dest)?;
         if self.has_hotspot {
             dest.write_str(" ")?;
             self.hotspot_x.to_css(dest)?;

components/style/values/specified/image.rs

@@ -181,7 +181,7 @@ impl Parse for Image {
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
     ) -> Result<Image, ParseError<'i>> {
-        Image::parse_with_cors_mode(context, input, CorsMode::None, /* allow_none = */ true)
+        Image::parse_with_cors_mode(context, input, CorsMode::None, /* allow_none = */ true, /* only_url = */ false)
     }
 }
 
@@ -191,23 +191,32 @@ impl Image {
         input: &mut Parser<'i, 't>,
         cors_mode: CorsMode,
         allow_none: bool,
+        only_url: bool,
     ) -> Result<Image, ParseError<'i>> {
         if allow_none && input.try_parse(|i| i.expect_ident_matching("none")).is_ok() {
             return Ok(generic::Image::None);
         }
+
         if let Ok(url) = input
             .try_parse(|input| SpecifiedImageUrl::parse_with_cors_mode(context, input, cors_mode))
         {
             return Ok(generic::Image::Url(url));
         }
-        if let Ok(gradient) = input.try_parse(|i| Gradient::parse(context, i)) {
-            return Ok(generic::Image::Gradient(Box::new(gradient)));
-        }
+
         if image_set_enabled() {
-            if let Ok(is) = input.try_parse(|input| ImageSet::parse(context, input, cors_mode)) {
+            if let Ok(is) = input.try_parse(|input| ImageSet::parse(context, input, cors_mode, only_url)) {
                 return Ok(generic::Image::ImageSet(Box::new(is)));
             }
         }
+
+        if only_url {
+            return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
+        }
+
+        if let Ok(gradient) = input.try_parse(|i| Gradient::parse(context, i)) {
+            return Ok(generic::Image::Gradient(Box::new(gradient)));
+        }
+
         if cross_fade_enabled() {
             if let Ok(cf) = input.try_parse(|input| CrossFade::parse(context, input, cors_mode)) {
                 return Ok(generic::Image::CrossFade(Box::new(cf)));
@@ -264,6 +273,21 @@ impl Image {
             input,
             CorsMode::Anonymous,
             /* allow_none = */ true,
+            /* only_url = */ false,
+        )
+    }
+
+    /// Provides an alternate method for parsing, but only for urls.
+    pub fn parse_only_url<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Image, ParseError<'i>> {
+        Self::parse_with_cors_mode(
+            context,
+            input,
+            CorsMode::None,
+            /* allow_none = */ false,
+            /* only_url = */ true,
         )
     }
 }
@@ -310,7 +334,7 @@ impl CrossFadeImage {
         cors_mode: CorsMode,
     ) -> Result<Self, ParseError<'i>> {
         if let Ok(image) = input.try_parse(|input| {
-            Image::parse_with_cors_mode(context, input, cors_mode, /* allow_none = */ false)
+            Image::parse_with_cors_mode(context, input, cors_mode, /* allow_none = */ false, /* only_url = */ false)
         }) {
             return Ok(Self::Image(image));
         }
@@ -339,10 +363,11 @@ impl ImageSet {
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
         cors_mode: CorsMode,
+        only_url: bool,
     ) -> Result<Self, ParseError<'i>> {
         input.expect_function_matching("image-set")?;
         let items = input.parse_nested_block(|input| {
-            input.parse_comma_separated(|input| ImageSetItem::parse(context, input, cors_mode))
+            input.parse_comma_separated(|input| ImageSetItem::parse(context, input, cors_mode, only_url))
         })?;
         Ok(Self {
             selected_index: 0,
@@ -356,6 +381,7 @@ impl ImageSetItem {
         context: &ParserContext,
         input: &mut Parser<'i, 't>,
         cors_mode: CorsMode,
+        only_url: bool,
     ) -> Result<Self, ParseError<'i>> {
         let image = match input.try_parse(|i| i.expect_url_or_string()) {
             Ok(url) => Image::Url(SpecifiedImageUrl::parse_from_string(
@@ -364,7 +390,7 @@ impl ImageSetItem {
                 cors_mode,
             )),
             Err(..) => Image::parse_with_cors_mode(
-                context, input, cors_mode, /* allow_none = */ false,
+                context, input, cors_mode, /* allow_none = */ false,  /* only_url = */ only_url
             )?,
         };
         let resolution = input

components/style/values/specified/ui.rs

@@ -7,17 +7,17 @@
 use crate::parser::{Parse, ParserContext};
 use crate::values::generics::ui as generics;
 use crate::values::specified::color::Color;
-use crate::values::specified::url::SpecifiedImageUrl;
+use crate::values::specified::image::Image;
 use crate::values::specified::Number;
 use cssparser::Parser;
 use std::fmt::{self, Write};
-use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
+use style_traits::{CssWriter, ParseError, SpecifiedValueInfo, StyleParseErrorKind, ToCss};
 
 /// A specified value for the `cursor` property.
 pub type Cursor = generics::GenericCursor<CursorImage>;
 
 /// A specified value for item of `image cursors`.
-pub type CursorImage = generics::GenericCursorImage<SpecifiedImageUrl, Number>;
+pub type CursorImage = generics::GenericCursorImage<Image, Number>;
 
 impl Parse for Cursor {
     /// cursor: [<url> [<number> <number>]?]# [auto | default | ...]
@@ -47,7 +47,7 @@ impl Parse for CursorImage {
     ) -> Result<Self, ParseError<'i>> {
         use crate::Zero;
 
-        let url = SpecifiedImageUrl::parse(context, input)?;
+        let image = Image::parse_only_url(context, input)?;
         let mut has_hotspot = false;
         let mut hotspot_x = Number::zero();
         let mut hotspot_y = Number::zero();
@@ -59,7 +59,7 @@ impl Parse for CursorImage {
         }
 
         Ok(Self {
-            url,
+            image,
             has_hotspot,
             hotspot_x,
             hotspot_y,
@@ -67,6 +67,10 @@ impl Parse for CursorImage {
     }
 }
 
+// This trait is manually implemented because we don't support the whole <image>
+// syntax for cursors
+impl SpecifiedValueInfo for CursorImage {}
+
 /// Specified value of `-moz-force-broken-image-icon`
 #[derive(
     Clone,