Split out is_element and is_text_node into a helper trait.

components/script/layout_wrapper.rs

@@ -58,7 +58,7 @@ use style::attr::AttrValue;
 use style::computed_values::display;
 use style::context::SharedStyleContext;
 use style::data::PrivateStyleData;
-use style::dom::{OpaqueNode, PresentationalHintsSynthetizer, TDocument, TElement, TNode, UnsafeNode};
+use style::dom::{NodeInfo, OpaqueNode, PresentationalHintsSynthetizer, TDocument, TElement, TNode, UnsafeNode};
 use style::element_state::*;
 use style::properties::{ComputedValues, PropertyDeclarationBlock};
 use style::refcell::{Ref, RefCell, RefMut};
@@ -111,6 +111,18 @@ impl<'ln> ServoLayoutNode<'ln> {
     }
 }
 
+impl<'ln> NodeInfo for ServoLayoutNode<'ln> {
+    fn is_element(&self) -> bool {
+        unsafe {
+            self.node.is_element_for_layout()
+        }
+    }
+
+    fn is_text_node(&self) -> bool {
+        self.script_type_id() == NodeTypeId::CharacterData(CharacterDataTypeId::Text)
+    }
+}
+
 impl<'ln> TNode for ServoLayoutNode<'ln> {
     type ConcreteElement = ServoLayoutElement<'ln>;
     type ConcreteDocument = ServoLayoutDocument<'ln>;
@@ -128,16 +140,6 @@ impl<'ln> TNode for ServoLayoutNode<'ln> {
         transmute(node)
     }
 
-    fn is_text_node(&self) -> bool {
-        self.script_type_id() == NodeTypeId::CharacterData(CharacterDataTypeId::Text)
-    }
-
-    fn is_element(&self) -> bool {
-        unsafe {
-            self.node.is_element_for_layout()
-        }
-    }
-
     fn dump(self) {
         self.dump_indent(0);
     }
@@ -727,6 +729,15 @@ impl<'ln> ServoThreadSafeLayoutNode<'ln> {
     }
 }
 
+impl<'ln> NodeInfo for ServoThreadSafeLayoutNode<'ln> {
+    fn is_element(&self) -> bool {
+        if let Some(LayoutNodeType::Element(_)) = self.type_id() { true } else { false }
+    }
+    fn is_text_node(&self) -> bool {
+        if let Some(LayoutNodeType::Text) = self.type_id() { true } else { false }
+    }
+}
+
 impl<'ln> ThreadSafeLayoutNode for ServoThreadSafeLayoutNode<'ln> {
     type ConcreteThreadSafeLayoutElement = ServoThreadSafeLayoutElement<'ln>;
     type ChildrenIterator = ThreadSafeLayoutNodeChildrenIterator<Self>;

components/script_layout_interface/wrapper_traits.rs

@@ -15,7 +15,7 @@ use std::sync::Arc;
 use string_cache::{Atom, Namespace};
 use style::computed_values::display;
 use style::context::SharedStyleContext;
-use style::dom::{PresentationalHintsSynthetizer, TNode};
+use style::dom::{NodeInfo, PresentationalHintsSynthetizer, TNode};
 use style::dom::OpaqueNode;
 use style::properties::ServoComputedValues;
 use style::refcell::{Ref, RefCell};
@@ -137,7 +137,7 @@ impl<ConcreteNode> Iterator for TreeIterator<ConcreteNode>
 
 /// A thread-safe version of `LayoutNode`, used during flow construction. This type of layout
 /// node does not allow any parents or siblings of nodes to be accessed, to avoid races.
-pub trait ThreadSafeLayoutNode: Clone + Copy + Sized + PartialEq {
+pub trait ThreadSafeLayoutNode: Clone + Copy + NodeInfo + PartialEq + Sized {
     type ConcreteThreadSafeLayoutElement:
         ThreadSafeLayoutElement<ConcreteThreadSafeLayoutNode = Self>
         + ::selectors::Element<Impl=ServoSelectorImpl>;
@@ -171,9 +171,6 @@ pub trait ThreadSafeLayoutNode: Clone + Copy + Sized + PartialEq {
     /// Returns an iterator over this node's children.
     fn children(&self) -> Self::ChildrenIterator;
 
-    #[inline]
-    fn is_element(&self) -> bool { if let Some(LayoutNodeType::Element(_)) = self.type_id() { true } else { false } }
-
     /// If this is an element, accesses the element data. Fails if this is not an element node.
     #[inline]
     fn as_element(&self) -> Self::ConcreteThreadSafeLayoutElement;

components/style/dom.rs

@@ -64,7 +64,16 @@ pub trait TRestyleDamage : Debug + PartialEq + BitOr<Output=Self> + Copy {
     fn rebuild_and_reflow() -> Self;
 }
 
-pub trait TNode : Sized + Copy + Clone {
+/// Simple trait to provide basic information about the type of an element.
+///
+/// We avoid exposing the full type id, since computing it in the general case
+/// would be difficult for Gecko nodes.
+pub trait NodeInfo {
+    fn is_element(&self) -> bool;
+    fn is_text_node(&self) -> bool;
+}
+
+pub trait TNode : Sized + Copy + Clone + NodeInfo {
     type ConcreteElement: TElement<ConcreteNode = Self, ConcreteDocument = Self::ConcreteDocument>;
     type ConcreteDocument: TDocument<ConcreteNode = Self, ConcreteElement = Self::ConcreteElement>;
     type ConcreteRestyleDamage: TRestyleDamage;
@@ -73,13 +82,6 @@ pub trait TNode : Sized + Copy + Clone {
     fn to_unsafe(&self) -> UnsafeNode;
     unsafe fn from_unsafe(n: &UnsafeNode) -> Self;
 
-    /// Returns whether this is a text node. It turns out that this is all the style system cares
-    /// about, and thus obviates the need to compute the full type id, which would be expensive in
-    /// Gecko.
-    fn is_text_node(&self) -> bool;
-
-    fn is_element(&self) -> bool;
-
     fn dump(self);
 
     fn dump_style(self);

components/style/matching.rs

@@ -12,7 +12,7 @@ use cache::{LRUCache, SimpleHashCache};
 use cascade_info::CascadeInfo;
 use context::{SharedStyleContext, StyleContext};
 use data::PrivateStyleData;
-use dom::{TElement, TNode, TRestyleDamage, UnsafeNode};
+use dom::{NodeInfo, TElement, TNode, TRestyleDamage, UnsafeNode};
 use properties::{ComputedValues, PropertyDeclarationBlock, cascade};
 use properties::longhands::display::computed_value as display;
 use selector_impl::{PseudoElement, TheSelectorImpl};

ports/geckolib/glue.rs

@@ -32,7 +32,7 @@ use std::sync::{Arc, Mutex};
 use std::sync::atomic::{AtomicBool, AtomicPtr, Ordering};
 use style::arc_ptr_eq;
 use style::context::{LocalStyleContextCreationInfo, ReflowGoal, SharedStyleContext};
-use style::dom::{TDocument, TElement, TNode};
+use style::dom::{NodeInfo, TDocument, TElement, TNode};
 use style::error_reporting::StdoutErrorReporter;
 use style::gecko_selector_impl::{GeckoSelectorImpl, PseudoElement};
 use style::parallel;

ports/geckolib/wrapper.rs

@@ -40,7 +40,7 @@ use std::ptr;
 use std::sync::Arc;
 use style::data::PrivateStyleData;
 use style::dom::{OpaqueNode, PresentationalHintsSynthetizer};
-use style::dom::{TDocument, TElement, TNode, TRestyleDamage, UnsafeNode};
+use style::dom::{NodeInfo, TDocument, TElement, TNode, TRestyleDamage, UnsafeNode};
 use style::element_state::ElementState;
 use style::error_reporting::StdoutErrorReporter;
 use style::gecko_selector_impl::{GeckoSelectorImpl, NonTSPseudoClass, PseudoElement};
@@ -125,6 +125,19 @@ impl BitOr for GeckoRestyleDamage {
 }
 
 
+impl<'ln> NodeInfo for GeckoNode<'ln> {
+    fn is_element(&self) -> bool {
+        unsafe {
+            Gecko_NodeIsElement(self.0)
+        }
+    }
+
+    fn is_text_node(&self) -> bool {
+        unsafe {
+            Gecko_IsTextNode(self.0)
+        }
+    }
+}
 
 impl<'ln> TNode for GeckoNode<'ln> {
     type ConcreteDocument = GeckoDocument<'ln>;
@@ -140,18 +153,6 @@ impl<'ln> TNode for GeckoNode<'ln> {
         GeckoNode(&*(n.0 as *mut RawGeckoNode))
     }
 
-    fn is_text_node(&self) -> bool {
-        unsafe {
-            Gecko_IsTextNode(self.0)
-        }
-    }
-
-    fn is_element(&self) -> bool {
-        unsafe {
-            Gecko_NodeIsElement(self.0)
-        }
-    }
-
     fn dump(self) {
         unimplemented!()
     }