auto merge of #1585 : pcwalton/servo/parallel-aux-init, r=metajack

Brings aux initialization time down to essentially zero (!)

r? @metajack

3 files changed, 19 insertions, 4 deletions

diff --git a/src/components/main/layout/context.rs b/src/components/main/layout/context.rs
index 801b474c824..9a405dad147 100644
--- a/src/components/main/layout/context.rs
+++ b/src/components/main/layout/context.rs
@@ -17,6 +17,7 @@ use std::rt::task::Task;
 
 use geom::size::Size2D;
 use gfx::font_context::{FontContext, FontContextInfo};
+use script::layout_interface::LayoutChan;
 use servo_msg::constellation_msg::ConstellationChan;
 use servo_net::local_image_cache::LocalImageCache;
 use servo_util::geometry::Au;
@@ -40,6 +41,9 @@ pub struct LayoutContext {
     /// The set of leaf DOM nodes.
     dom_leaf_set: MutexArc<DomLeafSet>,
 
+    /// A channel up to the layout task.
+    layout_chan: LayoutChan,
+
     /// The set of leaf flows.
     flow_leaf_set: MutexArc<FlowLeafSet>,
 
diff --git a/src/components/main/layout/layout_task.rs b/src/components/main/layout/layout_task.rs
index c8b9c435f14..28a19b657be 100644
--- a/src/components/main/layout/layout_task.rs
+++ b/src/components/main/layout/layout_task.rs
@@ -324,6 +324,7 @@ impl LayoutTask {
             constellation_chan: self.constellation_chan.clone(),
             dom_leaf_set: self.dom_leaf_set.clone(),
             flow_leaf_set: self.flow_leaf_set.clone(),
+            layout_chan: self.chan.clone(),
             font_context_info: font_context_info,
             stylist: &*self.stylist,
             reflow_root: OpaqueNode::from_layout_node(reflow_root),
@@ -549,10 +550,13 @@ impl LayoutTask {
                                       || {
             // Initialize layout data for each node.
             //
-            // FIXME: This is inefficient. We don't need an entire traversal to do this!
-            profile(time::LayoutAuxInitCategory, self.profiler_chan.clone(), || {
-                node.initialize_style_for_subtree(self.chan.clone());
-            });
+            // FIXME(pcwalton): This is inefficient. We don't need an entire traversal to do this
+            // in sequential mode!
+            if self.parallel_traversal.is_none() {
+                profile(time::LayoutAuxInitCategory, self.profiler_chan.clone(), || {
+                    node.initialize_style_for_subtree(self.chan.clone());
+                });
+            }
 
             // Perform CSS selector matching if necessary.
             match data.damage.level {
diff --git a/src/components/main/layout/parallel.rs b/src/components/main/layout/parallel.rs
index 859a3839333..a64abdc9a5c 100644
--- a/src/components/main/layout/parallel.rs
+++ b/src/components/main/layout/parallel.rs
@@ -8,6 +8,7 @@
 
 use css::matching::MatchMethods;
 use layout::context::LayoutContext;
+use layout::extra::LayoutAuxMethods;
 use layout::flow::{Flow, FlowLeafSet, PostorderFlowTraversal};
 use layout::flow;
 use layout::layout_task::{AssignHeightsAndStoreOverflowTraversal, BubbleWidthsTraversal};
@@ -130,6 +131,12 @@ fn match_and_cascade_node(unsafe_layout_node: UnsafeLayoutNode,
         // Get a real layout node.
         let node: LayoutNode = cast::transmute(unsafe_layout_node);
 
+        // Initialize layout data.
+        //
+        // FIXME(pcwalton): Stop allocating here. Ideally this should just be done by the HTML
+        // parser.
+        node.initialize_layout_data(layout_context.layout_chan.clone());
+
         if node.is_element() {
             // Perform the CSS selector matching.
             let stylist: &Stylist = cast::transmute(layout_context.stylist);