Support basic immutable CSSOM

components/script/dom/cssrulelist.rs

@@ -0,0 +1,67 @@
+/* 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::CSSRuleListBinding;
+use dom::bindings::codegen::Bindings::CSSRuleListBinding::CSSRuleListMethods;
+use dom::bindings::js::{JS, MutNullableHeap, Root};
+use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
+use dom::cssrule::CSSRule;
+use dom::cssstylesheet::CSSStyleSheet;
+use dom::window::Window;
+use style::stylesheets::CssRules;
+
+no_jsmanaged_fields!(CssRules);
+
+#[dom_struct]
+pub struct CSSRuleList {
+    reflector_: Reflector,
+    sheet: JS<CSSStyleSheet>,
+    #[ignore_heap_size_of = "Arc"]
+    rules: CssRules,
+    dom_rules: Vec<MutNullableHeap<JS<CSSRule>>>
+}
+
+impl CSSRuleList {
+    #[allow(unrooted_must_root)]
+    pub fn new_inherited(sheet: &CSSStyleSheet, rules: CssRules) -> CSSRuleList {
+        let dom_rules = rules.0.iter().map(|_| MutNullableHeap::new(None)).collect();
+        CSSRuleList {
+            reflector_: Reflector::new(),
+            sheet: JS::from_ref(sheet),
+            rules: rules,
+            dom_rules: dom_rules,
+        }
+    }
+
+    #[allow(unrooted_must_root)]
+    pub fn new(window: &Window, sheet: &CSSStyleSheet, rules: CssRules) -> Root<CSSRuleList> {
+        reflect_dom_object(box CSSRuleList::new_inherited(sheet, rules),
+                           window,
+                           CSSRuleListBinding::Wrap)
+    }
+}
+
+impl CSSRuleListMethods for CSSRuleList {
+    // https://drafts.csswg.org/cssom/#ref-for-dom-cssrulelist-item-1
+    fn Item(&self, idx: u32) -> Option<Root<CSSRule>> {
+        self.dom_rules.get(idx as usize).map(|rule| {
+            rule.or_init(|| {
+                CSSRule::new_specific(self.global().as_window(),
+                                     &self.sheet,
+                                     self.rules.0[idx as usize].clone())
+            })
+        })
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-cssrulelist-length
+    fn Length(&self) -> u32 {
+        self.dom_rules.len() as u32
+    }
+
+    // check-tidy: no specs after this line
+    fn IndexedGetter(&self, index: u32) -> Option<Root<CSSRule>> {
+        self.Item(index)
+    }
+}
+