Support basic immutable CSSOM

1 files changed, 103 insertions, 0 deletions

diff --git a/components/script/dom/cssrule.rs b/components/script/dom/cssrule.rs
new file mode 100644
index 00000000000..e46738bb1b4
--- /dev/null
+++ b/components/script/dom/cssrule.rs
@@ -0,0 +1,103 @@
+/* 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::CSSRuleBinding;
+use dom::bindings::codegen::Bindings::CSSRuleBinding::CSSRuleMethods;
+use dom::bindings::inheritance::Castable;
+use dom::bindings::js::{JS, MutNullableHeap, Root};
+use dom::bindings::reflector::{Reflector, reflect_dom_object};
+use dom::bindings::str::DOMString;
+use dom::cssfontfacerule::CSSFontFaceRule;
+use dom::csskeyframesrule::CSSKeyframesRule;
+use dom::cssmediarule::CSSMediaRule;
+use dom::cssnamespacerule::CSSNamespaceRule;
+use dom::cssstylerule::CSSStyleRule;
+use dom::cssstylesheet::CSSStyleSheet;
+use dom::cssviewportrule::CSSViewportRule;
+use dom::window::Window;
+use style::stylesheets::CssRule as StyleCssRule;
+
+
+#[dom_struct]
+pub struct CSSRule {
+    reflector_: Reflector,
+    parent: MutNullableHeap<JS<CSSStyleSheet>>,
+}
+
+impl CSSRule {
+    #[allow(unrooted_must_root)]
+    pub fn new_inherited(parent: &CSSStyleSheet) -> CSSRule {
+        CSSRule {
+            reflector_: Reflector::new(),
+            parent: MutNullableHeap::new(Some(parent)),
+        }
+    }
+
+    #[allow(unrooted_must_root)]
+    pub fn new(window: &Window, parent: &CSSStyleSheet) -> Root<CSSRule> {
+        reflect_dom_object(box CSSRule::new_inherited(parent),
+                           window,
+                           CSSRuleBinding::Wrap)
+    }
+
+    pub fn as_specific(&self) -> &SpecificCSSRule {
+        if let Some(rule) = self.downcast::<CSSStyleRule>() {
+            rule as &SpecificCSSRule
+        } else if let Some(rule) = self.downcast::<CSSFontFaceRule>() {
+            rule as &SpecificCSSRule
+        } else if let Some(rule) = self.downcast::<CSSKeyframesRule>() {
+            rule as &SpecificCSSRule
+        } else if let Some(rule) = self.downcast::<CSSMediaRule>() {
+            rule as &SpecificCSSRule
+        } else if let Some(rule) = self.downcast::<CSSNamespaceRule>() {
+            rule as &SpecificCSSRule
+        } else if let Some(rule) = self.downcast::<CSSViewportRule>() {
+            rule as &SpecificCSSRule
+        } else {
+            unreachable!()
+        }
+    }
+
+    // Given a StyleCssRule, create a new instance of a derived class of
+    // CSSRule based on which rule it is
+    pub fn new_specific(window: &Window, parent: &CSSStyleSheet,
+                        rule: StyleCssRule) -> Root<CSSRule> {
+        // be sure to update the match in as_specific when this is updated
+        match rule {
+            StyleCssRule::Style(s) => Root::upcast(CSSStyleRule::new(window, parent, s)),
+            StyleCssRule::FontFace(s) => Root::upcast(CSSFontFaceRule::new(window, parent, s)),
+            StyleCssRule::Keyframes(s) => Root::upcast(CSSKeyframesRule::new(window, parent, s)),
+            StyleCssRule::Media(s) => Root::upcast(CSSMediaRule::new(window, parent, s)),
+            StyleCssRule::Namespace(s) => Root::upcast(CSSNamespaceRule::new(window, parent, s)),
+            StyleCssRule::Viewport(s) => Root::upcast(CSSViewportRule::new(window, parent, s)),
+        }
+    }
+}
+
+impl CSSRuleMethods for CSSRule {
+    // https://drafts.csswg.org/cssom/#dom-cssrule-type
+    fn Type(&self) -> u16 {
+        self.as_specific().ty()
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-cssrule-parentstylesheet
+    fn GetParentStyleSheet(&self) -> Option<Root<CSSStyleSheet>> {
+        self.parent.get()
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-cssrule-csstext
+    fn CssText(&self) -> DOMString {
+        self.as_specific().get_css()
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-cssrule-csstext
+    fn SetCssText(&self, _: DOMString) {
+        // do nothing
+    }
+}
+
+pub trait SpecificCSSRule {
+    fn ty(&self) -> u16;
+    fn get_css(&self) -> DOMString;
+}