1 files changed, 82 insertions, 2 deletions
diff --git a/components/style/servo_selector_impl.rs b/components/style/servo_selector_impl.rs
index d1fdaf0336c..cee046e62f3 100644
--- a/components/style/servo_selector_impl.rs
+++ b/components/style/servo_selector_impl.rs
@@ -2,13 +2,16 @@
  * 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 attr::{AttrIdentifier, AttrValue};
 use element_state::ElementState;
 use error_reporting::StdoutErrorReporter;
 use parser::ParserContextExtraData;
+use restyle_hints::ElementSnapshot;
 use selector_impl::{SelectorImplExt, ElementExt, PseudoElementCascadeType, TheSelectorImpl};
-use selectors::Element;
-use selectors::parser::{ParserContext, SelectorImpl};
+use selectors::parser::{AttrSelector, ParserContext, SelectorImpl};
+use selectors::{Element, MatchAttrGeneric};
 use std::process;
+use string_cache::{Atom, Namespace};
 use stylesheets::{Stylesheet, Origin};
 use url::Url;
 use util::opts;
@@ -189,7 +192,84 @@ impl SelectorImplExt for ServoSelectorImpl {
     }
 }
 
+/// Servo's version of an element snapshot.
+#[derive(Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub struct ServoElementSnapshot {
+    pub state: Option<ElementState>,
+    pub attrs: Option<Vec<(AttrIdentifier, AttrValue)>>,
+    pub is_html_element_in_html_document: bool,
+}
+
+impl ServoElementSnapshot {
+    pub fn new(is_html_element_in_html_document: bool) -> Self {
+        ServoElementSnapshot {
+            state: None,
+            attrs: None,
+            is_html_element_in_html_document: is_html_element_in_html_document,
+        }
+    }
+
+    fn get_attr(&self, namespace: &Namespace, name: &Atom) -> Option<&AttrValue> {
+        self.attrs.as_ref().unwrap().iter()
+            .find(|&&(ref ident, _)| ident.local_name == *name &&
+                                     ident.namespace == *namespace)
+            .map(|&(_, ref v)| v)
+    }
+
+    fn get_attr_ignore_ns(&self, name: &Atom) -> Option<&AttrValue> {
+        self.attrs.as_ref().unwrap().iter()
+                  .find(|&&(ref ident, _)| ident.local_name == *name)
+                  .map(|&(_, ref v)| v)
+    }
+}
+
+impl ElementSnapshot for ServoElementSnapshot {
+    fn state(&self) -> Option<ElementState> {
+        self.state.clone()
+    }
+
+    fn has_attrs(&self) -> bool {
+        self.attrs.is_some()
+    }
+
+    fn id_attr(&self) -> Option<Atom> {
+        self.get_attr(&ns!(), &atom!("id")).map(|v| v.as_atom().clone())
+    }
+
+    fn has_class(&self, name: &Atom) -> bool {
+        self.get_attr(&ns!(), &atom!("class"))
+            .map_or(false, |v| v.as_tokens().iter().any(|atom| atom == name))
+    }
+
+    fn each_class<F>(&self, mut callback: F)
+        where F: FnMut(&Atom)
+    {
+        if let Some(v) = self.get_attr(&ns!(), &atom!("class")) {
+            for class in v.as_tokens() {
+                callback(class);
+            }
+        }
+    }
+}
+
+impl MatchAttrGeneric for ServoElementSnapshot {
+    fn match_attr<F>(&self, attr: &AttrSelector, test: F) -> bool
+        where F: Fn(&str) -> bool
+    {
+        use selectors::parser::NamespaceConstraint;
+        let html = self.is_html_element_in_html_document;
+        let local_name = if html { &attr.lower_name } else { &attr.name };
+        match attr.namespace {
+            NamespaceConstraint::Specific(ref ns) => self.get_attr(ns, local_name),
+            NamespaceConstraint::Any => self.get_attr_ignore_ns(local_name),
+        }.map_or(false, |v| test(v))
+    }
+}
+
 impl<E: Element<Impl=TheSelectorImpl, AttrString=String>> ElementExt for E {
+    type Snapshot = ServoElementSnapshot;
+
     fn is_link(&self) -> bool {
         self.match_non_ts_pseudo_class(NonTSPseudoClass::AnyLink)
     }