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layout: Switch display list building from bottom-up to top-down.

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This eliminates a lot of allocations and O(n^2) behavior.
This commit is contained in:
Patrick Walton 2016-03-02 15:41:50 -08:00
parent f4b95dd00b
commit d3d2dd05f2
5 changed files with 35 additions and 58 deletions
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33
components/layout/display_list_builder.rs
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@ -18,7 +18,7 @@ use context::LayoutContext;
use euclid::num::Zero;
use euclid::{Matrix4, Point2D, Point3D, Rect, SideOffsets2D, Size2D};
use flex::FlexFlow;
use flow::{self, BaseFlow, Flow, IS_ABSOLUTELY_POSITIONED};
use flow::{BaseFlow, Flow, IS_ABSOLUTELY_POSITIONED};
use flow_ref;
use fragment::{CoordinateSystem, Fragment, HAS_LAYER, ImageFragmentInfo, ScannedTextFragmentInfo};
use fragment::{SpecificFragmentInfo};
@ -86,21 +86,15 @@ impl<'a> DisplayListBuildState<'a> {
});
}
fn append_from(&mut self, other_list: &mut Option<Vec<DisplayListEntry>>) {
if let Some(mut other) = other_list.take() {
self.items.append(&mut other);
}
}
fn stacking_context_id(&self) -> StackingContextId {
self.stacking_context_id_stack.last().unwrap().clone()
}
fn push_stacking_context_id(&mut self, stacking_context_id: StackingContextId) {
pub fn push_stacking_context_id(&mut self, stacking_context_id: StackingContextId) {
self.stacking_context_id_stack.push(stacking_context_id);
}
fn pop_stacking_context_id(&mut self) {
pub fn pop_stacking_context_id(&mut self) {
self.stacking_context_id_stack.pop();
assert!(!self.stacking_context_id_stack.is_empty());
}
@ -1736,11 +1730,6 @@ impl BlockFlowDisplayListBuilding for BlockFlow {
clip,
&self.base.stacking_relative_position_of_display_port);
// Add children.
for kid in self.base.children.iter_mut() {
state.append_from(&mut flow::mut_base(kid).display_list_building_result);
}
self.base.build_display_items_for_debugging_tint(state, self.fragment.node);
}
}
@ -1805,22 +1794,6 @@ impl InlineFlowDisplayListBuilding for InlineFlow {
DisplayListSection::Content,
&self.base.clip,
&self.base.stacking_relative_position_of_display_port);
match fragment.specific {
SpecificFragmentInfo::InlineBlock(ref mut block_flow) => {
let block_flow = flow_ref::deref_mut(&mut block_flow.flow_ref);
state.append_from(&mut flow::mut_base(block_flow).display_list_building_result)
}
SpecificFragmentInfo::InlineAbsoluteHypothetical(ref mut block_flow) => {
let block_flow = flow_ref::deref_mut(&mut block_flow.flow_ref);
state.append_from(&mut flow::mut_base(block_flow).display_list_building_result)
}
SpecificFragmentInfo::InlineAbsolute(ref mut block_flow) => {
let block_flow = flow_ref::deref_mut(&mut block_flow.flow_ref);
state.append_from(&mut flow::mut_base(block_flow).display_list_building_result)
}
_ => {}
}
}
fn build_display_list_for_inline(&mut self, state: &mut DisplayListBuildState) {