Add initial style system support for @counter-style rules

components/script/dom/cssrule.rs

@@ -78,6 +78,7 @@ impl CSSRule {
             StyleCssRule::Import(s) => Root::upcast(CSSImportRule::new(window, parent_stylesheet, s)),
             StyleCssRule::Style(s) => Root::upcast(CSSStyleRule::new(window, parent_stylesheet, s)),
             StyleCssRule::FontFace(s) => Root::upcast(CSSFontFaceRule::new(window, parent_stylesheet, s)),
+            StyleCssRule::CounterStyle(_) => unimplemented!(),
             StyleCssRule::Keyframes(s) => Root::upcast(CSSKeyframesRule::new(window, parent_stylesheet, s)),
             StyleCssRule::Media(s) => Root::upcast(CSSMediaRule::new(window, parent_stylesheet, s)),
             StyleCssRule::Namespace(s) => Root::upcast(CSSNamespaceRule::new(window, parent_stylesheet, s)),

components/style/counter_style.rs

@@ -0,0 +1,150 @@
+/* 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/. */
+
+//! The [`@counter-style`][counter-style] at-rule.
+//!
+//! [counter-style]: https://drafts.csswg.org/css-counter-styles/
+
+use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser, Parser};
+#[cfg(feature = "gecko")] use gecko::rules::CounterStyleDescriptors;
+#[cfg(feature = "gecko")] use gecko_bindings::structs::nsCSSCounterDesc;
+use parser::{ParserContext, log_css_error, Parse};
+use shared_lock::{SharedRwLockReadGuard, ToCssWithGuard};
+use std::fmt;
+use style_traits::ToCss;
+use values::CustomIdent;
+
+/// Parse the body (inside `{}`) of an @counter-style rule
+pub fn parse_counter_style_body(name: CustomIdent, context: &ParserContext, input: &mut Parser)
+                            -> Result<CounterStyleRule, ()> {
+    let mut rule = CounterStyleRule::initial(name);
+    {
+        let parser = CounterStyleRuleParser {
+            context: context,
+            rule: &mut rule,
+        };
+        let mut iter = DeclarationListParser::new(input, parser);
+        while let Some(declaration) = iter.next() {
+            if let Err(range) = declaration {
+                let pos = range.start;
+                let message = format!("Unsupported @counter-style descriptor declaration: '{}'",
+                                      iter.input.slice(range));
+                log_css_error(iter.input, pos, &*message, context);
+            }
+        }
+    }
+    Ok(rule)
+}
+
+struct CounterStyleRuleParser<'a, 'b: 'a> {
+    context: &'a ParserContext<'b>,
+    rule: &'a mut CounterStyleRule,
+}
+
+/// Default methods reject all at rules.
+impl<'a, 'b> AtRuleParser for CounterStyleRuleParser<'a, 'b> {
+    type Prelude = ();
+    type AtRule = ();
+}
+
+
+macro_rules! counter_style_descriptors {
+    (
+        $( #[$doc: meta] $name: tt $ident: ident / $gecko_ident: ident: $ty: ty = $initial: expr, )+
+    ) => {
+        /// An @counter-style rule
+        #[derive(Debug)]
+        pub struct CounterStyleRule {
+            name: CustomIdent,
+            $(
+                #[$doc]
+                $ident: $ty,
+            )+
+        }
+
+        impl CounterStyleRule {
+            fn initial(name: CustomIdent) -> Self {
+                CounterStyleRule {
+                    name: name,
+                    $(
+                        $ident: $initial,
+                    )+
+                }
+            }
+
+            /// Convert to Gecko types
+            #[cfg(feature = "gecko")]
+            pub fn set_descriptors(&self, descriptors: &mut CounterStyleDescriptors) {
+                $(
+                    descriptors[nsCSSCounterDesc::$gecko_ident as usize].set_from(&self.$ident)
+                )*
+            }
+        }
+
+       impl<'a, 'b> DeclarationParser for CounterStyleRuleParser<'a, 'b> {
+            type Declaration = ();
+
+            fn parse_value(&mut self, name: &str, input: &mut Parser) -> Result<(), ()> {
+                match_ignore_ascii_case! { name,
+                    $(
+                        $name => {
+                            // DeclarationParser also calls parse_entirely
+                            // so we’d normally not need to,
+                            // but in this case we do because we set the value as a side effect
+                            // rather than returning it.
+                            let value = input.parse_entirely(|i| Parse::parse(self.context, i))?;
+                            self.rule.$ident = value
+                        }
+                    )*
+                    _ => return Err(())
+                }
+                Ok(())
+            }
+        }
+
+        impl ToCssWithGuard for CounterStyleRule {
+            fn to_css<W>(&self, _guard: &SharedRwLockReadGuard, dest: &mut W) -> fmt::Result
+            where W: fmt::Write {
+                dest.write_str("@counter-style ")?;
+                self.name.to_css(dest)?;
+                dest.write_str(" {\n")?;
+                $(
+                    dest.write_str(concat!("  ", $name, ": "))?;
+                    ToCss::to_css(&self.$ident, dest)?;
+                    dest.write_str(";\n")?;
+                )+
+                dest.write_str("}")
+            }
+        }
+    }
+}
+
+counter_style_descriptors! {
+    /// The algorithm for constructing a string representation of a counter value
+    "system" system / eCSSCounterDesc_System: System = System::Symbolic,
+}
+
+/// Value of the 'system' descriptor
+#[derive(Debug)]
+pub enum System {
+    /// Cycles through provided symbols, doubling, tripling, etc.
+    Symbolic,
+}
+
+impl Parse for System {
+    fn parse(_context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        match_ignore_ascii_case! { &input.expect_ident()?,
+            "symbolic" => Ok(System::Symbolic),
+            _ => Err(())
+        }
+    }
+}
+
+impl ToCss for System {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            System::Symbolic => dest.write_str("symbolic")
+        }
+    }
+}

components/style/gecko/rules.rs

@@ -6,10 +6,11 @@
 
 use computed_values::{font_style, font_weight, font_stretch};
 use computed_values::font_family::FamilyName;
+use counter_style::System;
 use cssparser::UnicodeRange;
 use font_face::{FontFaceRuleData, Source};
 use gecko_bindings::bindings;
-use gecko_bindings::structs::{self, nsCSSFontFaceRule, nsCSSValue};
+use gecko_bindings::structs::{self, nsCSSFontFaceRule, nsCSSValue, nsCSSCounterDesc};
 use gecko_bindings::sugar::ns_css_value::ToNsCssValue;
 use gecko_bindings::sugar::refptr::{RefPtr, UniqueRefPtr};
 use shared_lock::{ToCssWithGuard, SharedRwLockReadGuard};
@@ -133,3 +134,15 @@ impl ToCssWithGuard for FontFaceRule {
         write!(dest, "{}", css_text)
     }
 }
+
+/// The type of nsCSSCounterStyleRule::mValues
+pub type CounterStyleDescriptors = [nsCSSValue; nsCSSCounterDesc::eCSSCounterDesc_COUNT as usize];
+
+impl ToNsCssValue for System {
+    fn convert(&self, v: &mut nsCSSValue) {
+        match *self {
+            System::Symbolic => v.set_enum(structs::NS_STYLE_COUNTER_SYSTEM_SYMBOLIC as i32),
+        }
+    }
+}
+

components/style/lib.rs

@@ -89,6 +89,7 @@ pub mod bloom;
 pub mod cache;
 pub mod cascade_info;
 pub mod context;
+pub mod counter_style;
 pub mod custom_properties;
 pub mod data;
 pub mod dom;

components/style/stylesheets.rs

@@ -7,6 +7,7 @@
 #![deny(missing_docs)]
 
 use {Atom, Prefix, Namespace};
+use counter_style::{CounterStyleRule, parse_counter_style_body};
 use cssparser::{AtRuleParser, Parser, QualifiedRuleParser};
 use cssparser::{AtRuleType, RuleListParser, Token, parse_one_rule};
 use cssparser::ToCss as ParserToCss;
@@ -290,6 +291,7 @@ pub enum CssRule {
     Style(Arc<Locked<StyleRule>>),
     Media(Arc<Locked<MediaRule>>),
     FontFace(Arc<Locked<FontFaceRule>>),
+    CounterStyle(Arc<Locked<CounterStyleRule>>),
     Viewport(Arc<Locked<ViewportRule>>),
     Keyframes(Arc<Locked<KeyframesRule>>),
     Supports(Arc<Locked<SupportsRule>>),
@@ -336,6 +338,7 @@ impl CssRule {
             CssRule::Import(_) => CssRuleType::Import,
             CssRule::Media(_) => CssRuleType::Media,
             CssRule::FontFace(_) => CssRuleType::FontFace,
+            CssRule::CounterStyle(_) => CssRuleType::CounterStyle,
             CssRule::Keyframes(_) => CssRuleType::Keyframes,
             CssRule::Namespace(_) => CssRuleType::Namespace,
             CssRule::Viewport(_) => CssRuleType::Viewport,
@@ -373,6 +376,7 @@ impl CssRule {
             CssRule::Namespace(_) |
             CssRule::Style(_) |
             CssRule::FontFace(_) |
+            CssRule::CounterStyle(_) |
             CssRule::Viewport(_) |
             CssRule::Keyframes(_) |
             CssRule::Page(_) => {
@@ -446,6 +450,7 @@ impl ToCssWithGuard for CssRule {
             CssRule::Import(ref lock) => lock.read_with(guard).to_css(guard, dest),
             CssRule::Style(ref lock) => lock.read_with(guard).to_css(guard, dest),
             CssRule::FontFace(ref lock) => lock.read_with(guard).to_css(guard, dest),
+            CssRule::CounterStyle(ref lock) => lock.read_with(guard).to_css(guard, dest),
             CssRule::Viewport(ref lock) => lock.read_with(guard).to_css(guard, dest),
             CssRule::Keyframes(ref lock) => lock.read_with(guard).to_css(guard, dest),
             CssRule::Media(ref lock) => lock.read_with(guard).to_css(guard, dest),
@@ -835,6 +840,7 @@ rule_filter! {
     effective_style_rules(Style => StyleRule),
     effective_media_rules(Media => MediaRule),
     effective_font_face_rules(FontFace => FontFaceRule),
+    effective_counter_style_rules(CounterStyle => CounterStyleRule),
     effective_viewport_rules(Viewport => ViewportRule),
     effective_keyframes_rules(Keyframes => KeyframesRule),
     effective_supports_rules(Supports => SupportsRule),
@@ -916,6 +922,8 @@ pub enum VendorPrefix {
 enum AtRulePrelude {
     /// A @font-face rule prelude.
     FontFace,
+    /// A @counter-style rule prelude, with its counter style name.
+    CounterStyle(CustomIdent),
     /// A @media rule prelude, with its media queries.
     Media(Arc<Locked<MediaList>>),
     /// An @supports rule, with its conditional
@@ -1103,6 +1111,14 @@ impl<'a, 'b> AtRuleParser for NestedRuleParser<'a, 'b> {
             "font-face" => {
                 Ok(AtRuleType::WithBlock(AtRulePrelude::FontFace))
             },
+            "counter-style" => {
+                if !cfg!(feature = "gecko") {
+                    // Support for this rule is not fully implemented in Servo yet.
+                    return Err(())
+                }
+                let name = CustomIdent::from_ident(input.expect_ident()?, &["decimal", "none"])?;
+                Ok(AtRuleType::WithBlock(AtRulePrelude::CounterStyle(name)))
+            },
             "viewport" => {
                 if is_viewport_enabled() {
                     Ok(AtRuleType::WithBlock(AtRulePrelude::Viewport))
@@ -1149,6 +1165,11 @@ impl<'a, 'b> AtRuleParser for NestedRuleParser<'a, 'b> {
                 Ok(CssRule::FontFace(Arc::new(self.shared_lock.wrap(
                    parse_font_face_block(&context, input).into()))))
             }
+            AtRulePrelude::CounterStyle(name) => {
+                let context = ParserContext::new_with_rule_type(self.context, Some(CssRuleType::CounterStyle));
+                Ok(CssRule::CounterStyle(Arc::new(self.shared_lock.wrap(
+                   parse_counter_style_body(name, &context, input)?))))
+            }
             AtRulePrelude::Media(media_queries) => {
                 Ok(CssRule::Media(Arc::new(self.shared_lock.wrap(MediaRule {
                     media_queries: media_queries,