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

components/script/dom/cssconditionrule.rs

@@ -0,0 +1,53 @@
+/* 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 dom::bindings::codegen::Bindings::CSSConditionRuleBinding::CSSConditionRuleMethods;
+use dom::bindings::inheritance::Castable;
+use dom::bindings::str::DOMString;
+use dom::cssgroupingrule::CSSGroupingRule;
+use dom::cssmediarule::CSSMediaRule;
+use dom::cssstylesheet::CSSStyleSheet;
+use dom::csssupportsrule::CSSSupportsRule;
+use parking_lot::RwLock;
+use std::sync::Arc;
+use style::stylesheets::CssRules as StyleCssRules;
+
+#[dom_struct]
+pub struct CSSConditionRule {
+    cssgroupingrule: CSSGroupingRule,
+}
+
+impl CSSConditionRule {
+    pub fn new_inherited(parent_stylesheet: &CSSStyleSheet,
+                         rules: Arc<RwLock<StyleCssRules>>) -> CSSConditionRule {
+        CSSConditionRule {
+            cssgroupingrule: CSSGroupingRule::new_inherited(parent_stylesheet, rules),
+        }
+    }
+
+}
+
+impl CSSConditionRuleMethods for CSSConditionRule {
+    /// https://drafts.csswg.org/css-conditional-3/#dom-cssconditionrule-conditiontext
+    fn ConditionText(&self) -> DOMString {
+        if let Some(rule) = self.downcast::<CSSMediaRule>() {
+            rule.get_condition_text()
+        } else if let Some(rule) = self.downcast::<CSSSupportsRule>() {
+            rule.get_condition_text()
+        } else {
+            unreachable!()
+        }
+    }
+
+    /// https://drafts.csswg.org/css-conditional-3/#dom-cssconditionrule-conditiontext
+    fn SetConditionText(&self, text: DOMString) {
+        if let Some(rule) = self.downcast::<CSSMediaRule>() {
+            rule.set_condition_text(text)
+        } else if let Some(rule) = self.downcast::<CSSSupportsRule>() {
+            rule.set_condition_text(text)
+        } else {
+            unreachable!()
+        }
+    }
+}