1 files changed, 36 insertions, 1 deletions
diff --git a/components/script/dom/cssstylerule.rs b/components/script/dom/cssstylerule.rs
index 607f2cfb816..f9df3afc2ad 100644
--- a/components/script/dom/cssstylerule.rs
+++ b/components/script/dom/cssstylerule.rs
@@ -2,7 +2,10 @@
  * 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 as CssParser, ParserInput as CssParserInput};
+use cssparser::ToCss;
 use dom::bindings::codegen::Bindings::CSSStyleRuleBinding::{self, CSSStyleRuleMethods};
+use dom::bindings::codegen::Bindings::WindowBinding::WindowBinding::WindowMethods;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{JS, MutNullableJS, Root};
 use dom::bindings::reflector::{DomObject, reflect_dom_object};
@@ -12,9 +15,12 @@ use dom::cssstyledeclaration::{CSSModificationAccess, CSSStyleDeclaration, CSSSt
 use dom::cssstylesheet::CSSStyleSheet;
 use dom::window::Window;
 use dom_struct::dom_struct;
+use selectors::parser::SelectorList;
+use std::mem;
+use style::selector_parser::SelectorParser;
 use style::shared_lock::{Locked, ToCssWithGuard};
 use style::stylearc::Arc;
-use style::stylesheets::StyleRule;
+use style::stylesheets::{StyleRule, Origin};
 
 #[dom_struct]
 pub struct CSSStyleRule {
@@ -71,4 +77,33 @@ impl CSSStyleRuleMethods for CSSStyleRule {
             )
         })
     }
+
+    // https://drafts.csswg.org/cssom/#dom-cssstylerule-selectortext
+    fn SelectorText(&self) -> DOMString {
+        let guard = self.cssrule.shared_lock().read();
+        let stylerule = self.stylerule.read_with(&guard);
+        return DOMString::from_string(stylerule.selectors.to_css_string());
+    }
+
+    // https://drafts.csswg.org/cssom/#dom-cssstylerule-selectortext
+    fn SetSelectorText(&self, value: DOMString) {
+        // It's not clear from the spec if we should use the stylesheet's namespaces.
+        // https://github.com/w3c/csswg-drafts/issues/1511
+        let namespaces = self.cssrule.parent_stylesheet().style_stylesheet().contents.namespaces.read();
+        let parser = SelectorParser {
+            stylesheet_origin: Origin::Author,
+            namespaces: &namespaces,
+        };
+        let mut css_parser = CssParserInput::new(&*value);
+        let mut css_parser = CssParser::new(&mut css_parser);
+        if let Ok(mut s) = SelectorList::parse(&parser, &mut css_parser) {
+            // This mirrors what we do in CSSStyleOwner::mutate_associated_block.
+            let mut guard = self.cssrule.shared_lock().write();
+            let mut stylerule = self.stylerule.write_with(&mut guard);
+            mem::swap(&mut stylerule.selectors, &mut s);
+            // It seems like we will want to avoid having to invalidate all
+            // stylesheets eventually!
+            self.global().as_window().Document().invalidate_stylesheets();
+        }
+    }
 }