Add 'fallback' descriptor to @counter-style

components/style/counter_style.rs

@@ -6,6 +6,7 @@
 //!
 //! [counter-style]: https://drafts.csswg.org/css-counter-styles/
 
+use Atom;
 use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser, Parser, Token};
 use cssparser::{serialize_string, serialize_identifier};
 #[cfg(feature = "gecko")] use gecko::rules::CounterStyleDescriptors;
@@ -148,6 +149,10 @@ counter_style_descriptors! {
 
     /// https://drafts.csswg.org/css-counter-styles/#counter-style-pad
     "pad" pad / eCSSCounterDesc_Pad: Pad = Pad(0, Symbol::String("".to_owned()));
+
+    /// https://drafts.csswg.org/css-counter-styles/#counter-style-fallback
+    "fallback" fallback / eCSSCounterDesc_Fallback: Fallback =
+        Fallback(CustomIdent(Atom::from("decimal")));
 }
 
 /// https://drafts.csswg.org/css-counter-styles/#counter-style-system
@@ -358,3 +363,19 @@ impl ToCss for Pad {
         self.1.to_css(dest)
     }
 }
+
+/// https://drafts.csswg.org/css-counter-styles/#counter-style-fallback
+#[derive(Debug)]
+pub struct Fallback(pub CustomIdent);
+
+impl Parse for Fallback {
+    fn parse(_context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        parse_counter_style_name(input).map(Fallback)
+    }
+}
+
+impl ToCss for Fallback {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        self.0.to_css(dest)
+    }
+}

components/style/gecko/rules.rs

@@ -221,3 +221,9 @@ impl ToNsCssValue for counter_style::Pad {
         //nscssvalue.set_pair(min_length, pad_with);
     }
 }
+
+impl ToNsCssValue for counter_style::Fallback {
+    fn convert(&self, nscssvalue: &mut nsCSSValue) {
+        nscssvalue.set_ident_from_atom(&self.0 .0)
+    }
+}

components/style/gecko_bindings/sugar/ns_css_value.rs

@@ -124,6 +124,11 @@ impl nsCSSValue {
         self.set_string_from_atom_internal(s, nsCSSUnit::eCSSUnit_String)
     }
 
+    /// Set to a ident value from the given atom
+    pub fn set_ident_from_atom(&mut self, s: &Atom) {
+        self.set_string_from_atom_internal(s, nsCSSUnit::eCSSUnit_Ident)
+    }
+
     /// Set to an identifier value
     pub fn set_ident(&mut self, s: &str) {
         self.set_string_internal(s, nsCSSUnit::eCSSUnit_Ident)