1 files changed, 53 insertions, 0 deletions
diff --git a/servo/components/style/gecko/traversal.rs b/servo/components/style/gecko/traversal.rs
new file mode 100644
index 0000000000..71d1a2f949
--- /dev/null
+++ b/servo/components/style/gecko/traversal.rs
@@ -0,0 +1,53 @@
+/* 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 https://mozilla.org/MPL/2.0/. */
+
+//! Gecko-specific bits for the styling DOM traversal.
+
+use crate::context::{SharedStyleContext, StyleContext};
+use crate::dom::{TElement, TNode};
+use crate::gecko::wrapper::{GeckoElement, GeckoNode};
+use crate::traversal::{recalc_style_at, DomTraversal, PerLevelTraversalData};
+
+/// This is the simple struct that Gecko uses to encapsulate a DOM traversal for
+/// styling.
+pub struct RecalcStyleOnly<'a> {
+    shared: SharedStyleContext<'a>,
+}
+
+impl<'a> RecalcStyleOnly<'a> {
+    /// Create a `RecalcStyleOnly` traversal from a `SharedStyleContext`.
+    pub fn new(shared: SharedStyleContext<'a>) -> Self {
+        RecalcStyleOnly { shared: shared }
+    }
+}
+
+impl<'recalc, 'le> DomTraversal<GeckoElement<'le>> for RecalcStyleOnly<'recalc> {
+    fn process_preorder<F>(
+        &self,
+        traversal_data: &PerLevelTraversalData,
+        context: &mut StyleContext<GeckoElement<'le>>,
+        node: GeckoNode<'le>,
+        note_child: F,
+    ) where
+        F: FnMut(GeckoNode<'le>),
+    {
+        if let Some(el) = node.as_element() {
+            let mut data = unsafe { el.ensure_data() };
+            recalc_style_at(self, traversal_data, context, el, &mut data, note_child);
+        }
+    }
+
+    fn process_postorder(&self, _: &mut StyleContext<GeckoElement<'le>>, _: GeckoNode<'le>) {
+        unreachable!();
+    }
+
+    /// We don't use the post-order traversal for anything.
+    fn needs_postorder_traversal() -> bool {
+        false
+    }
+
+    fn shared_context(&self) -> &SharedStyleContext {
+        &self.shared
+    }
+}