CSSOM bits for @supports: CSSConditionRule and CSSSupportsRule, with conditionText attribute

components/script/dom/csssupportsrule.rs

@@ -0,0 +1,77 @@
+/* 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/. */
+
+use cssparser::Parser;
+use dom::bindings::codegen::Bindings::CSSSupportsRuleBinding;
+use dom::bindings::codegen::Bindings::WindowBinding::WindowBinding::WindowMethods;
+use dom::bindings::js::Root;
+use dom::bindings::reflector::{DomObject, reflect_dom_object};
+use dom::bindings::str::DOMString;
+use dom::cssconditionrule::CSSConditionRule;
+use dom::cssrule::SpecificCSSRule;
+use dom::cssstylesheet::CSSStyleSheet;
+use dom::window::Window;
+use parking_lot::RwLock;
+use std::sync::Arc;
+use style::parser::ParserContext;
+use style::stylesheets::SupportsRule;
+use style::supports::SupportsCondition;
+use style_traits::ToCss;
+
+#[dom_struct]
+pub struct CSSSupportsRule {
+    cssrule: CSSConditionRule,
+    #[ignore_heap_size_of = "Arc"]
+    supportsrule: Arc<RwLock<SupportsRule>>,
+}
+
+impl CSSSupportsRule {
+    fn new_inherited(parent_stylesheet: &CSSStyleSheet, supportsrule: Arc<RwLock<SupportsRule>>)
+                     -> CSSSupportsRule {
+        let list = supportsrule.read().rules.clone();
+        CSSSupportsRule {
+            cssrule: CSSConditionRule::new_inherited(parent_stylesheet, list),
+            supportsrule: supportsrule,
+        }
+    }
+
+    #[allow(unrooted_must_root)]
+    pub fn new(window: &Window, parent_stylesheet: &CSSStyleSheet,
+               supportsrule: Arc<RwLock<SupportsRule>>) -> Root<CSSSupportsRule> {
+        reflect_dom_object(box CSSSupportsRule::new_inherited(parent_stylesheet, supportsrule),
+                           window,
+                           CSSSupportsRuleBinding::Wrap)
+    }
+
+    /// https://drafts.csswg.org/css-conditional-3/#the-csssupportsrule-interface
+    pub fn get_condition_text(&self) -> DOMString {
+        let rule = self.supportsrule.read();
+        rule.condition.to_css_string().into()
+    }
+
+    /// https://drafts.csswg.org/css-conditional-3/#the-csssupportsrule-interface
+    pub fn set_condition_text(&self, text: DOMString) {
+        let mut input = Parser::new(&text);
+        let cond = SupportsCondition::parse(&mut input);
+        if let Ok(cond) = cond {
+            let url = self.global().as_window().Document().url();
+            let context = ParserContext::new_for_cssom(&url);
+            let enabled = cond.eval(&context);
+            let mut rule = self.supportsrule.write();
+            rule.condition = cond;
+            rule.enabled = enabled;
+        }
+    }
+}
+
+impl SpecificCSSRule for CSSSupportsRule {
+    fn ty(&self) -> u16 {
+        use dom::bindings::codegen::Bindings::CSSRuleBinding::CSSRuleConstants;
+        CSSRuleConstants::SUPPORTS_RULE
+    }
+
+    fn get_css(&self) -> DOMString {
+        self.supportsrule.read().to_css_string().into()
+    }
+}