Move most of geckolib into style::gecko

components/style/gecko/traversal.rs

@@ -0,0 +1,49 @@
+/* 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 context::{LocalStyleContext, SharedStyleContext, StyleContext};
+use dom::OpaqueNode;
+use gecko::context::StandaloneStyleContext;
+use gecko::wrapper::GeckoNode;
+use std::mem;
+use traversal::{DomTraversalContext, recalc_style_at};
+use traversal::RestyleResult;
+
+pub struct RecalcStyleOnly<'lc> {
+    context: StandaloneStyleContext<'lc>,
+    root: OpaqueNode,
+}
+
+impl<'lc, 'ln> DomTraversalContext<GeckoNode<'ln>> for RecalcStyleOnly<'lc> {
+    type SharedContext = SharedStyleContext;
+    #[allow(unsafe_code)]
+    fn new<'a>(shared: &'a Self::SharedContext, root: OpaqueNode) -> Self {
+        // See the comment in RecalcStyleAndConstructFlows::new for an explanation of why this is
+        // necessary.
+        let shared_lc: &'lc Self::SharedContext = unsafe { mem::transmute(shared) };
+        RecalcStyleOnly {
+            context: StandaloneStyleContext::new(shared_lc),
+            root: root,
+        }
+    }
+
+    fn process_preorder(&self, node: GeckoNode<'ln>) -> RestyleResult {
+        // FIXME(pcwalton): Stop allocating here. Ideally this should just be done by the HTML
+        // parser.
+        node.initialize_data();
+
+        recalc_style_at(&self.context, self.root, node)
+    }
+
+    fn process_postorder(&self, _: GeckoNode<'ln>) {
+        unreachable!();
+    }
+
+    /// We don't use the post-order traversal for anything.
+    fn needs_postorder_traversal(&self) -> bool { false }
+
+    fn local_context(&self) -> &LocalStyleContext {
+        self.context.local_context()
+    }
+}