style: Cleanup ParserContext::new_with_rule_type.

components/script/dom/css.rs

@@ -36,9 +36,13 @@ impl CSS {
         decl.push_str(&value);
         let decl = Declaration(decl);
         let url = win.Document().url();
-        let context = ParserContext::new_for_cssom(&url, win.css_error_reporter(), Some(CssRuleType::Supports),
-                                                   PARSING_MODE_DEFAULT,
-                                                   QuirksMode::NoQuirks);
+        let context = ParserContext::new_for_cssom(
+            &url,
+            win.css_error_reporter(),
+            Some(CssRuleType::Style),
+            PARSING_MODE_DEFAULT,
+            QuirksMode::NoQuirks
+        );
         decl.eval(&context)
     }
 
@@ -49,9 +53,13 @@ impl CSS {
         let cond = parse_condition_or_declaration(&mut input);
         if let Ok(cond) = cond {
             let url = win.Document().url();
-            let context = ParserContext::new_for_cssom(&url, win.css_error_reporter(), Some(CssRuleType::Supports),
-                                                       PARSING_MODE_DEFAULT,
-                                                       QuirksMode::NoQuirks);
+            let context = ParserContext::new_for_cssom(
+                &url,
+                win.css_error_reporter(),
+                Some(CssRuleType::Style),
+                PARSING_MODE_DEFAULT,
+                QuirksMode::NoQuirks
+            );
             cond.eval(&context)
         } else {
             false

components/style/parser.rs

@@ -102,17 +102,18 @@ impl<'a> ParserContext<'a> {
     /// Create a parser context based on a previous context, but with a modified rule type.
     pub fn new_with_rule_type(
         context: &'a ParserContext,
-        rule_type: Option<CssRuleType>
+        rule_type: CssRuleType,
+        namespaces: &'a Namespaces,
     ) -> ParserContext<'a> {
         ParserContext {
             stylesheet_origin: context.stylesheet_origin,
             url_data: context.url_data,
             error_reporter: context.error_reporter,
-            rule_type: rule_type,
+            rule_type: Some(rule_type),
             line_number_offset: context.line_number_offset,
             parsing_mode: context.parsing_mode,
             quirks_mode: context.quirks_mode,
-            namespaces: context.namespaces,
+            namespaces: Some(namespaces),
         }
     }
 

components/style/stylesheets/font_feature_values_rule.rs

@@ -322,14 +322,17 @@ macro_rules! font_feature_values_blocks {
                 }
             }
 
-            fn parse_block<'t>(&mut self, prelude: Self::Prelude, input: &mut Parser<'i, 't>)
-                               -> Result<Self::AtRule, ParseError<'i>> {
-                let context = ParserContext::new_with_rule_type(self.context, Some(CssRuleType::FontFeatureValues));
+            fn parse_block<'t>(
+                &mut self,
+                prelude: Self::Prelude,
+                input: &mut Parser<'i, 't>
+            ) -> Result<Self::AtRule, ParseError<'i>> {
+                debug_assert_eq!(self.context.rule_type(), CssRuleType::FontFeatureValues);
                 match prelude {
                     $(
                         BlockType::$ident_camel => {
                             let parser = FFVDeclarationsParser {
-                                context: &context,
+                                context: &self.context,
                                 declarations: &mut self.rule.$ident,
                             };
 
@@ -338,7 +341,7 @@ macro_rules! font_feature_values_blocks {
                                 if let Err(err) = declaration {
                                     let error = ContextualParseError::UnsupportedKeyframePropertyDeclaration(
                                         err.slice, err.error);
-                                    context.log_css_error(err.location, error);
+                                    self.context.log_css_error(err.location, error);
                                 }
                             }
                         },

components/style/stylesheets/keyframes_rule.rs

@@ -450,8 +450,14 @@ struct KeyframeListParser<'a> {
 }
 
 /// Parses a keyframe list from CSS input.
-pub fn parse_keyframe_list(context: &ParserContext, input: &mut Parser, shared_lock: &SharedRwLock)
-                           -> Vec<Arc<Locked<Keyframe>>> {
+pub fn parse_keyframe_list(
+    context: &ParserContext,
+    input: &mut Parser,
+    shared_lock: &SharedRwLock
+) -> Vec<Arc<Locked<Keyframe>>> {
+    debug_assert!(context.namespaces.is_some(),
+                  "Parsing a keyframe list from a context without namespaces?");
+
     let mut declarations = SourcePropertyDeclaration::new();
     RuleListParser::new_for_nested_rule(input, KeyframeListParser {
         context: context,
@@ -487,7 +493,13 @@ impl<'a, 'i> QualifiedRuleParser<'i> for KeyframeListParser<'a> {
 
     fn parse_block<'t>(&mut self, prelude: Self::Prelude, input: &mut Parser<'i, 't>)
                        -> Result<Self::QualifiedRule, ParseError<'i>> {
-        let context = ParserContext::new_with_rule_type(self.context, Some(CssRuleType::Keyframe));
+        let context =
+            ParserContext::new_with_rule_type(
+                self.context,
+                CssRuleType::Keyframe,
+                self.context.namespaces.unwrap(),
+            );
+
         let parser = KeyframeDeclarationParser {
             context: &context,
             declarations: self.declarations,

components/style/stylesheets/mod.rs

@@ -134,7 +134,7 @@ impl MallocSizeOfWithGuard for CssRule {
 }
 
 #[allow(missing_docs)]
-#[derive(PartialEq, Eq, Copy, Clone)]
+#[derive(PartialEq, Eq, Copy, Clone, Debug)]
 pub enum CssRuleType {
     // https://drafts.csswg.org/cssom/#the-cssrule-interface
     Style               = 1,

components/style/stylesheets/rule_parser.rs

@@ -44,9 +44,8 @@ pub struct TopLevelRuleParser<'a> {
     pub loader: Option<&'a StylesheetLoader>,
     /// The top-level parser context.
     ///
-    /// This won't contain any namespaces, and will only be filled right because
-    /// parsing style rules, on the assumption that they're the only rules that
-    /// need them.
+    /// This won't contain any namespaces, and only nested parsers created with
+    /// `ParserContext::new_with_rule_type` will.
     pub context: ParserContext<'a>,
     /// The current state of the parser.
     pub state: State,
@@ -295,10 +294,8 @@ impl<'a, 'b> NestedRuleParser<'a, 'b> {
         input: &mut Parser,
         rule_type: CssRuleType
     ) -> Arc<Locked<CssRules>> {
-        let context = ParserContext::new_with_rule_type(
-            self.context,
-            Some(rule_type),
-        );
+        let context =
+            ParserContext::new_with_rule_type(self.context, rule_type, self.namespaces);
 
         let nested_parser = NestedRuleParser {
             stylesheet_origin: self.stylesheet_origin,
@@ -423,17 +420,33 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
     ) -> Result<CssRule, ParseError<'i>> {
         match prelude {
             AtRulePrelude::FontFace(location) => {
-                let context = ParserContext::new_with_rule_type(self.context, Some(CssRuleType::FontFace));
+                let context =
+                    ParserContext::new_with_rule_type(
+                        self.context,
+                        CssRuleType::FontFace,
+                        self.namespaces,
+                    );
+
                 Ok(CssRule::FontFace(Arc::new(self.shared_lock.wrap(
                    parse_font_face_block(&context, input, location).into()))))
             }
             AtRulePrelude::FontFeatureValues(family_names, location) => {
-                let context = ParserContext::new_with_rule_type(self.context, Some(CssRuleType::FontFeatureValues));
+                let context =
+                    ParserContext::new_with_rule_type(
+                        self.context,
+                        CssRuleType::FontFeatureValues,
+                        self.namespaces,
+                    );
                 Ok(CssRule::FontFeatureValues(Arc::new(self.shared_lock.wrap(
                     FontFeatureValuesRule::parse(&context, input, family_names, location)))))
             }
             AtRulePrelude::CounterStyle(name) => {
-                let context = ParserContext::new_with_rule_type(self.context, Some(CssRuleType::CounterStyle));
+                let context =
+                    ParserContext::new_with_rule_type(
+                        self.context,
+                        CssRuleType::CounterStyle,
+                        self.namespaces,
+                    );
                 Ok(CssRule::CounterStyle(Arc::new(self.shared_lock.wrap(
                    parse_counter_style_body(name, &context, input)?.into()))))
             }
@@ -445,7 +458,13 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
                 }))))
             }
             AtRulePrelude::Supports(cond, location) => {
-                let enabled = cond.eval(self.context);
+                let eval_context =
+                    ParserContext::new_with_rule_type(
+                        self.context,
+                        CssRuleType::Style,
+                        self.namespaces,
+                    );
+                let enabled = cond.eval(&eval_context);
                 Ok(CssRule::Supports(Arc::new(self.shared_lock.wrap(SupportsRule {
                     condition: cond,
                     rules: self.parse_nested_rules(input, CssRuleType::Supports),
@@ -454,12 +473,23 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
                 }))))
             }
             AtRulePrelude::Viewport => {
-                let context = ParserContext::new_with_rule_type(self.context, Some(CssRuleType::Viewport));
+                let context =
+                    ParserContext::new_with_rule_type(
+                        self.context,
+                        CssRuleType::Viewport,
+                        self.namespaces,
+                    );
                 Ok(CssRule::Viewport(Arc::new(self.shared_lock.wrap(
                    ViewportRule::parse(&context, input)?))))
             }
             AtRulePrelude::Keyframes(name, prefix, location) => {
-                let context = ParserContext::new_with_rule_type(self.context, Some(CssRuleType::Keyframes));
+                let context =
+                    ParserContext::new_with_rule_type(
+                        self.context,
+                        CssRuleType::Keyframes,
+                        self.namespaces,
+                    );
+
                 Ok(CssRule::Keyframes(Arc::new(self.shared_lock.wrap(KeyframesRule {
                     name: name,
                     keyframes: parse_keyframe_list(&context, input, self.shared_lock),
@@ -468,7 +498,12 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
                 }))))
             }
             AtRulePrelude::Page(location) => {
-                let context = ParserContext::new_with_rule_type(self.context, Some(CssRuleType::Page));
+                let context =
+                    ParserContext::new_with_rule_type(
+                        self.context,
+                        CssRuleType::Page,
+                        self.namespaces,
+                    );
                 let declarations = parse_property_declaration_list(&context, input);
                 Ok(CssRule::Page(Arc::new(self.shared_lock.wrap(PageRule {
                     block: Arc::new(self.shared_lock.wrap(declarations)),
@@ -520,8 +555,12 @@ impl<'a, 'b, 'i> QualifiedRuleParser<'i> for NestedRuleParser<'a, 'b> {
         prelude: QualifiedRuleParserPrelude,
         input: &mut Parser<'i, 't>
     ) -> Result<CssRule, ParseError<'i>> {
-        let mut context = ParserContext::new_with_rule_type(self.context, Some(CssRuleType::Style));
-        context.namespaces = Some(self.namespaces);
+        let context =
+            ParserContext::new_with_rule_type(
+                self.context,
+                CssRuleType::Style,
+                self.namespaces,
+            );
         let declarations = parse_property_declaration_list(&context, input);
         Ok(CssRule::Style(Arc::new(self.shared_lock.wrap(StyleRule {
             selectors: prelude.selectors,

components/style/stylesheets/supports_rule.rs

@@ -241,16 +241,19 @@ impl Declaration {
     /// Determine if a declaration parses
     ///
     /// https://drafts.csswg.org/css-conditional-3/#support-definition
-    pub fn eval(&self, cx: &ParserContext) -> bool {
+    pub fn eval(&self, context: &ParserContext) -> bool {
+        debug_assert_eq!(context.rule_type(), CssRuleType::Style);
+
         let mut input = ParserInput::new(&self.0);
         let mut input = Parser::new(&mut input);
         input.parse_entirely(|input| {
             let prop = input.expect_ident().unwrap().as_ref().to_owned();
             input.expect_colon().unwrap();
-            let context = ParserContext::new_with_rule_type(cx, Some(CssRuleType::Style));
+
             let property_context = PropertyParserContext::new(&context);
             let id = PropertyId::parse(&prop, Some(&property_context))
-                    .map_err(|_| StyleParseError::UnspecifiedError)?;
+                        .map_err(|_| StyleParseError::UnspecifiedError)?;
+
             let mut declarations = SourcePropertyDeclaration::new();
             input.parse_until_before(Delimiter::Bang, |input| {
                 PropertyDeclaration::parse_into(&mut declarations, id, &context, input)

ports/geckolib/glue.rs

@@ -1508,6 +1508,11 @@ pub extern "C" fn Servo_KeyframesRule_AppendRule(
     let css = unsafe { css.as_ref().unwrap().as_str_unchecked() };
     let contents = StylesheetContents::as_arc(&contents);
     let global_style_data = &*GLOBAL_STYLE_DATA;
+
+    // FIXME(emilio): What happens with namespaces here?
+    //
+    // We seem to ignore it, but someone could still set content: attr(..) from
+    // a declaration inside the keyframe block.
     match Keyframe::parse(css, &contents, &global_style_data.shared_lock) {
         Ok(keyframe) => {
             write_locked_arc(rule, |rule: &mut KeyframesRule| {
@@ -2811,9 +2816,16 @@ pub extern "C" fn Servo_CSSSupports(cond: *const nsACString) -> bool {
     if let Ok(cond) = cond {
         let url_data = unsafe { dummy_url_data() };
         let reporter = NullReporter;
-        let context = ParserContext::new_for_cssom(url_data, &reporter, Some(CssRuleType::Style),
-                                                   PARSING_MODE_DEFAULT,
-                                                   QuirksMode::NoQuirks);
+        // NOTE(emilio): The supports API is not associated to any stylesheet,
+        // so the fact that there are no namespace map here is fine.
+        let context =
+            ParserContext::new_for_cssom(
+                url_data,
+                &reporter,
+                Some(CssRuleType::Style),
+                PARSING_MODE_DEFAULT,
+                QuirksMode::NoQuirks,
+            );
         cond.eval(&context)
     } else {
         false