1 files changed, 90 insertions, 0 deletions
diff --git a/components/layout/css/node_util.rs b/components/layout/css/node_util.rs
new file mode 100644
index 00000000000..150995428ea
--- /dev/null
+++ b/components/layout/css/node_util.rs
@@ -0,0 +1,90 @@
+/* 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 incremental::RestyleDamage;
+use util::LayoutDataAccess;
+use wrapper::{TLayoutNode, ThreadSafeLayoutNode};
+use wrapper::{After, AfterBlock, Before, BeforeBlock, Normal};
+use std::mem;
+use style::ComputedValues;
+use sync::Arc;
+
+pub trait NodeUtil {
+    fn get_css_select_results<'a>(&'a self) -> &'a Arc<ComputedValues>;
+    fn have_css_select_results(&self) -> bool;
+
+    fn get_restyle_damage(&self) -> RestyleDamage;
+    fn set_restyle_damage(&self, damage: RestyleDamage);
+}
+
+impl<'ln> NodeUtil for ThreadSafeLayoutNode<'ln> {
+    /// Returns the style results for the given node. If CSS selector
+    /// matching has not yet been performed, fails.
+    #[inline]
+    fn get_css_select_results<'a>(&'a self) -> &'a Arc<ComputedValues> {
+        unsafe {
+            let layout_data_ref = self.borrow_layout_data();
+            match self.get_pseudo_element_type() {
+                Before | BeforeBlock => {
+                     mem::transmute(layout_data_ref.as_ref()
+                                                   .unwrap()
+                                                   .data
+                                                   .before_style
+                                                   .as_ref()
+                                                   .unwrap())
+                }
+                After | AfterBlock => {
+                    mem::transmute(layout_data_ref.as_ref()
+                                                  .unwrap()
+                                                  .data
+                                                  .after_style
+                                                  .as_ref()
+                                                  .unwrap())
+                }
+                Normal => {
+                    mem::transmute(layout_data_ref.as_ref()
+                                                  .unwrap()
+                                                  .shared_data
+                                                  .style
+                                                  .as_ref()
+                                                  .unwrap())
+                }
+            }
+        }
+    }
+
+    /// Does this node have a computed style yet?
+    fn have_css_select_results(&self) -> bool {
+        let layout_data_ref = self.borrow_layout_data();
+        layout_data_ref.get_ref().shared_data.style.is_some()
+    }
+
+    /// Get the description of how to account for recent style changes.
+    /// This is a simple bitfield and fine to copy by value.
+    fn get_restyle_damage(&self) -> RestyleDamage {
+        // For DOM elements, if we haven't computed damage yet, assume the worst.
+        // Other nodes don't have styles.
+        let default = if self.node_is_element() {
+            RestyleDamage::all()
+        } else {
+            RestyleDamage::empty()
+        };
+
+        let layout_data_ref = self.borrow_layout_data();
+        layout_data_ref
+            .get_ref()
+            .data
+            .restyle_damage
+            .unwrap_or(default)
+    }
+
+    /// Set the restyle damage field.
+    fn set_restyle_damage(&self, damage: RestyleDamage) {
+        let mut layout_data_ref = self.mutate_layout_data();
+        match &mut *layout_data_ref {
+            &Some(ref mut layout_data) => layout_data.data.restyle_damage = Some(damage),
+            _ => fail!("no layout data for this node"),
+        }
+    }
+}