1 files changed, 264 insertions, 0 deletions
diff --git a/servo/components/style/stylesheets/font_palette_values_rule.rs b/servo/components/style/stylesheets/font_palette_values_rule.rs
new file mode 100644
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+++ b/servo/components/style/stylesheets/font_palette_values_rule.rs
@@ -0,0 +1,264 @@
+/* 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 https://mozilla.org/MPL/2.0/. */
+
+//! The [`@font-palette-values`][font-palette-values] at-rule.
+//!
+//! [font-palette-values]: https://drafts.csswg.org/css-fonts/#font-palette-values
+
+use crate::error_reporting::ContextualParseError;
+use crate::gecko_bindings::bindings::Gecko_AppendPaletteValueHashEntry;
+use crate::gecko_bindings::bindings::{Gecko_SetFontPaletteBase, Gecko_SetFontPaletteOverride};
+use crate::gecko_bindings::structs::gfx::FontPaletteValueSet;
+use crate::gecko_bindings::structs::gfx::FontPaletteValueSet_PaletteValues_kDark;
+use crate::gecko_bindings::structs::gfx::FontPaletteValueSet_PaletteValues_kLight;
+use crate::parser::{Parse, ParserContext};
+use crate::shared_lock::{SharedRwLockReadGuard, ToCssWithGuard};
+use crate::str::CssStringWriter;
+use crate::stylesheets::font_feature_values_rule::parse_family_name_list;
+use crate::values::computed::font::FamilyName;
+use crate::values::specified::Color as SpecifiedColor;
+use crate::values::specified::NonNegativeInteger;
+use crate::values::DashedIdent;
+use cssparser::{
+    AtRuleParser, CowRcStr, DeclarationParser, Parser, QualifiedRuleParser, RuleBodyItemParser,
+    RuleBodyParser, SourceLocation,
+};
+use selectors::parser::SelectorParseErrorKind;
+use std::fmt::{self, Write};
+use style_traits::{Comma, OneOrMoreSeparated};
+use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
+
+#[allow(missing_docs)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToShmem)]
+pub struct FontPaletteOverrideColor {
+    index: NonNegativeInteger,
+    color: SpecifiedColor,
+}
+
+impl Parse for FontPaletteOverrideColor {
+    fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<FontPaletteOverrideColor, ParseError<'i>> {
+        let index = NonNegativeInteger::parse(context, input)?;
+        let location = input.current_source_location();
+        let color = SpecifiedColor::parse(context, input)?;
+        // Only absolute colors are accepted here.
+        if let SpecifiedColor::Absolute { .. } = color {
+            Ok(FontPaletteOverrideColor { index, color })
+        } else {
+            Err(location.new_custom_error(StyleParseErrorKind::UnspecifiedError))
+        }
+    }
+}
+
+impl ToCss for FontPaletteOverrideColor {
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: fmt::Write,
+    {
+        self.index.to_css(dest)?;
+        dest.write_char(' ')?;
+        self.color.to_css(dest)
+    }
+}
+
+impl OneOrMoreSeparated for FontPaletteOverrideColor {
+    type S = Comma;
+}
+
+impl OneOrMoreSeparated for FamilyName {
+    type S = Comma;
+}
+
+#[allow(missing_docs)]
+#[derive(Clone, Debug, MallocSizeOf, Parse, PartialEq, ToCss, ToShmem)]
+pub enum FontPaletteBase {
+    Light,
+    Dark,
+    Index(NonNegativeInteger),
+}
+
+/// The [`@font-palette-values`][font-palette-values] at-rule.
+///
+/// [font-palette-values]: https://drafts.csswg.org/css-fonts/#font-palette-values
+#[derive(Clone, Debug, PartialEq, ToShmem)]
+pub struct FontPaletteValuesRule {
+    /// Palette name.
+    pub name: DashedIdent,
+    /// Font family list for @font-palette-values rule.
+    /// Family names cannot contain generic families. FamilyName
+    /// also accepts only non-generic names.
+    pub family_names: Vec<FamilyName>,
+    /// The base palette.
+    pub base_palette: Option<FontPaletteBase>,
+    /// The list of override colors.
+    pub override_colors: Vec<FontPaletteOverrideColor>,
+    /// The line and column of the rule's source code.
+    pub source_location: SourceLocation,
+}
+
+impl FontPaletteValuesRule {
+    /// Creates an empty FontPaletteValuesRule with given location and name.
+    fn new(name: DashedIdent, location: SourceLocation) -> Self {
+        FontPaletteValuesRule {
+            name,
+            family_names: vec![],
+            base_palette: None,
+            override_colors: vec![],
+            source_location: location,
+        }
+    }
+
+    /// Parses a `FontPaletteValuesRule`.
+    pub fn parse(
+        context: &ParserContext,
+        input: &mut Parser,
+        name: DashedIdent,
+        location: SourceLocation,
+    ) -> Self {
+        let mut rule = FontPaletteValuesRule::new(name, location);
+        let mut parser = FontPaletteValuesDeclarationParser {
+            context,
+            rule: &mut rule,
+        };
+        let mut iter = RuleBodyParser::new(input, &mut parser);
+        while let Some(declaration) = iter.next() {
+            if let Err((error, slice)) = declaration {
+                let location = error.location;
+                let error =
+                    ContextualParseError::UnsupportedFontPaletteValuesDescriptor(slice, error);
+                context.log_css_error(location, error);
+            }
+        }
+        rule
+    }
+
+    /// Prints inside of `@font-palette-values` block.
+    fn value_to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
+    {
+        if !self.family_names.is_empty() {
+            dest.write_str("font-family: ")?;
+            self.family_names.to_css(dest)?;
+            dest.write_str("; ")?;
+        }
+        if let Some(base) = &self.base_palette {
+            dest.write_str("base-palette: ")?;
+            base.to_css(dest)?;
+            dest.write_str("; ")?;
+        }
+        if !self.override_colors.is_empty() {
+            dest.write_str("override-colors: ")?;
+            self.override_colors.to_css(dest)?;
+            dest.write_str("; ")?;
+        }
+        Ok(())
+    }
+
+    /// Convert to Gecko FontPaletteValueSet.
+    pub fn to_gecko_palette_value_set(&self, dest: *mut FontPaletteValueSet) {
+        for ref family in self.family_names.iter() {
+            let family = family.name.to_ascii_lowercase();
+            let palette_values = unsafe {
+                Gecko_AppendPaletteValueHashEntry(dest, family.as_ptr(), self.name.0.as_ptr())
+            };
+            if let Some(base_palette) = &self.base_palette {
+                unsafe {
+                    Gecko_SetFontPaletteBase(
+                        palette_values,
+                        match &base_palette {
+                            FontPaletteBase::Light => FontPaletteValueSet_PaletteValues_kLight,
+                            FontPaletteBase::Dark => FontPaletteValueSet_PaletteValues_kDark,
+                            FontPaletteBase::Index(i) => i.0.value() as i32,
+                        },
+                    );
+                }
+            }
+            for c in &self.override_colors {
+                if let SpecifiedColor::Absolute(ref absolute) = c.color {
+                    unsafe {
+                        Gecko_SetFontPaletteOverride(
+                            palette_values,
+                            c.index.0.value(),
+                            (&absolute.color) as *const _ as *mut _,
+                        );
+                    }
+                }
+            }
+        }
+    }
+}
+
+impl ToCssWithGuard for FontPaletteValuesRule {
+    fn to_css(&self, _guard: &SharedRwLockReadGuard, dest: &mut CssStringWriter) -> fmt::Result {
+        dest.write_str("@font-palette-values ")?;
+        self.name.to_css(&mut CssWriter::new(dest))?;
+        dest.write_str(" { ")?;
+        self.value_to_css(&mut CssWriter::new(dest))?;
+        dest.write_char('}')
+    }
+}
+
+/// Parser for declarations in `FontPaletteValuesRule`.
+struct FontPaletteValuesDeclarationParser<'a> {
+    context: &'a ParserContext<'a>,
+    rule: &'a mut FontPaletteValuesRule,
+}
+
+impl<'a, 'i> AtRuleParser<'i> for FontPaletteValuesDeclarationParser<'a> {
+    type Prelude = ();
+    type AtRule = ();
+    type Error = StyleParseErrorKind<'i>;
+}
+
+impl<'a, 'i> QualifiedRuleParser<'i> for FontPaletteValuesDeclarationParser<'a> {
+    type Prelude = ();
+    type QualifiedRule = ();
+    type Error = StyleParseErrorKind<'i>;
+}
+
+fn parse_override_colors<'i, 't>(
+    context: &ParserContext,
+    input: &mut Parser<'i, 't>,
+) -> Result<Vec<FontPaletteOverrideColor>, ParseError<'i>> {
+    input.parse_comma_separated(|i| FontPaletteOverrideColor::parse(context, i))
+}
+
+impl<'a, 'b, 'i> DeclarationParser<'i> for FontPaletteValuesDeclarationParser<'a> {
+    type Declaration = ();
+    type Error = StyleParseErrorKind<'i>;
+
+    fn parse_value<'t>(
+        &mut self,
+        name: CowRcStr<'i>,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<(), ParseError<'i>> {
+        match_ignore_ascii_case! { &*name,
+            "font-family" => {
+                self.rule.family_names = parse_family_name_list(self.context, input)?
+            },
+            "base-palette" => {
+                self.rule.base_palette = Some(input.parse_entirely(|i| FontPaletteBase::parse(self.context, i))?)
+            },
+            "override-colors" => {
+                self.rule.override_colors = parse_override_colors(self.context, input)?
+            },
+            _ => return Err(input.new_custom_error(SelectorParseErrorKind::UnexpectedIdent(name.clone()))),
+        }
+        Ok(())
+    }
+}
+
+impl<'a, 'i> RuleBodyItemParser<'i, (), StyleParseErrorKind<'i>>
+    for FontPaletteValuesDeclarationParser<'a>
+{
+    fn parse_declarations(&self) -> bool {
+        true
+    }
+    fn parse_qualified(&self) -> bool {
+        false
+    }
+}