auto merge of #1589 : pcwalton/servo/stop-removing-flows, r=larsbergstrom

to be leaves.

60% improvement in flow tree construction time on the rainbow page.

r? @larsbergstrom

1 files changed, 12 insertions, 20 deletions

diff --git a/src/components/main/layout/construct.rs b/src/components/main/layout/construct.rs
index e2605e6bd6c..dbb0f9d9b5b 100644
--- a/src/components/main/layout/construct.rs
+++ b/src/components/main/layout/construct.rs
@@ -26,7 +26,7 @@ use layout::box_::{Box, GenericBox, IframeBox, IframeBoxInfo, ImageBox, ImageBox
 use layout::box_::{UnscannedTextBox, UnscannedTextBoxInfo, InlineInfo, InlineParentInfo};
 use layout::context::LayoutContext;
 use layout::float_context::FloatType;
-use layout::flow::{BaseFlow, Flow, LeafSet, MutableOwnedFlowUtils};
+use layout::flow::{BaseFlow, Flow, ImmutableFlowUtils, LeafSet, MutableOwnedFlowUtils};
 use layout::inline::InlineFlow;
 use layout::text::TextRunScanner;
 use layout::util::{LayoutDataAccess, OpaqueNode};
@@ -274,13 +274,10 @@ impl<'fc> FlowConstructor<'fc> {
 
         let inline_base = BaseFlow::new(self.next_flow_id(), node);
         let mut inline_flow = ~InlineFlow::from_boxes(inline_base, boxes) as ~Flow;
-        self.layout_context.leaf_set.access(|leaf_set| leaf_set.insert(&inline_flow));
+        self.layout_context.leaf_set.access(|leaf_set| inline_flow.mark_as_leaf(leaf_set));
         TextRunScanner::new().scan_for_runs(self.font_context, inline_flow);
 
-        let mut inline_flow = Some(inline_flow);
-        self.layout_context.leaf_set.access(|leaf_set| {
-            flow.add_new_child(inline_flow.take_unwrap(), leaf_set)
-        })
+        flow.add_new_child(inline_flow)
     }
 
     /// Creates an inline flow from a set of inline boxes, if present, and adds it as a child of
@@ -323,10 +320,7 @@ impl<'fc> FlowConstructor<'fc> {
                     self.flush_inline_boxes_to_flow_if_necessary(&mut opt_boxes_for_inline_flow,
                                                                  flow,
                                                                  node);
-                    let mut kid_flow = Some(kid_flow);
-                    self.layout_context.leaf_set.access(|leaf_set| {
-                        flow.add_new_child(kid_flow.take_unwrap(), leaf_set)
-                    })
+                    flow.add_new_child(kid_flow)
                 }
                 ConstructionItemConstructionResult(InlineBoxesConstructionItem(
                         InlineBoxesConstructionResult {
@@ -366,10 +360,7 @@ impl<'fc> FlowConstructor<'fc> {
 
                                 // Push the flow generated by the {ib} split onto our list of
                                 // flows.
-                                let mut kid_flow = Some(kid_flow);
-                                self.layout_context.leaf_set.access(|leaf_set| {
-                                    flow.add_new_child(kid_flow.take_unwrap(), leaf_set)
-                                })
+                                flow.add_new_child(kid_flow)
                             }
                         }
                     }
@@ -386,6 +377,13 @@ impl<'fc> FlowConstructor<'fc> {
         self.flush_inline_boxes_to_flow_if_necessary(&mut opt_boxes_for_inline_flow,
                                                      flow,
                                                      node);
+
+        // The flow is done. If it ended up with no kids, add the flow to the leaf set.
+        if flow.child_count() == 0 {
+            self.layout_context.leaf_set.access(|leaf_set| flow.mark_as_leaf(leaf_set))
+        } else {
+            flow.mark_as_nonleaf()
+        }
     }
 
     /// Builds a flow for a node with `display: block`. This yields a `BlockFlow` with possibly
@@ -395,9 +393,6 @@ impl<'fc> FlowConstructor<'fc> {
         let base = BaseFlow::new(self.next_flow_id(), node);
         let box_ = self.build_box_for_node(node);
         let mut flow = ~BlockFlow::from_box(base, box_, is_fixed) as ~Flow;
-
-        self.layout_context.leaf_set.access(|leaf_set| leaf_set.insert(&flow));
-
         self.build_children_of_block_flow(&mut flow, node);
         flow
     }
@@ -410,9 +405,6 @@ impl<'fc> FlowConstructor<'fc> {
         let box_ = self.build_box_for_node(node);
 
         let mut flow = ~BlockFlow::float_from_box(base, float_type, box_) as ~Flow;
-
-        self.layout_context.leaf_set.access(|leaf_set| leaf_set.insert(&flow));
-
         self.build_children_of_block_flow(&mut flow, node);
         flow
     }