Sync changes from mozilla-central gfx/wr

webrender/src/scene.rs

@@ -2,7 +2,7 @@
  * 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 api::{BuiltDisplayList, ColorF, DynamicProperties, Epoch, FontRenderMode};
+use api::{BuiltDisplayList, DisplayItemCache, ColorF, DynamicProperties, Epoch, FontRenderMode};
 use api::{PipelineId, PropertyBinding, PropertyBindingId, MixBlendMode, StackingContext};
 use api::units::*;
 use crate::composite::CompositorKind;
@@ -134,6 +134,7 @@ pub struct ScenePipeline {
     pub content_size: LayoutSize,
     pub background_color: Option<ColorF>,
     pub display_list: BuiltDisplayList,
+    pub display_list_cache: DisplayItemCache,
 }
 
 /// A complete representation of the layout bundling visible pipelines together.
@@ -168,12 +169,20 @@ impl Scene {
         viewport_size: LayoutSize,
         content_size: LayoutSize,
     ) {
+        let pipeline = self.pipelines.remove(&pipeline_id);
+        let mut display_list_cache = pipeline.map_or(Default::default(), |p| {
+            p.display_list_cache
+        });
+
+        display_list_cache.update(&display_list);
+
         let new_pipeline = ScenePipeline {
             pipeline_id,
             viewport_size,
             content_size,
             background_color,
             display_list,
+            display_list_cache,
         };
 
         self.pipelines.insert(pipeline_id, new_pipeline);

webrender/src/scene_builder_thread.rs

@@ -255,6 +255,7 @@ pub struct SceneBuilderThread {
     size_of_ops: Option<MallocSizeOfOps>,
     hooks: Option<Box<dyn SceneBuilderHooks + Send>>,
     simulate_slow_ms: u32,
+    removed_pipelines: FastHashSet<PipelineId>
 }
 
 pub struct SceneBuilderThreadChannels {
@@ -299,6 +300,7 @@ impl SceneBuilderThread {
             size_of_ops,
             hooks,
             simulate_slow_ms: 0,
+            removed_pipelines: FastHashSet::default(),
         }
     }
 
@@ -529,7 +531,24 @@ impl SceneBuilderThread {
                       .or_insert_with(|| Document::new(Scene::new()));
         let scene = &mut doc.scene;
 
+        for &(pipeline_id, epoch) in &txn.epoch_updates {
+            scene.update_epoch(pipeline_id, epoch);
+        }
+
+        if let Some(id) = txn.set_root_pipeline {
+            scene.set_root_pipeline_id(id);
+        }
+
+        for &(pipeline_id, _) in &txn.removed_pipelines {
+            scene.remove_pipeline(pipeline_id);
+            self.removed_pipelines.insert(pipeline_id);
+        }
+
         for update in txn.display_list_updates.drain(..) {
+            if self.removed_pipelines.contains(&update.pipeline_id) {
+                continue;
+            }
+
             scene.set_display_list(
                 update.pipeline_id,
                 update.epoch,
@@ -540,17 +559,7 @@ impl SceneBuilderThread {
             );
         }
 
-        for &(pipeline_id, epoch) in &txn.epoch_updates {
-            scene.update_epoch(pipeline_id, epoch);
-        }
-
-        if let Some(id) = txn.set_root_pipeline {
-            scene.set_root_pipeline_id(id);
-        }
-
-        for &(pipeline_id, _) in &txn.removed_pipelines {
-            scene.remove_pipeline(pipeline_id)
-        }
+        self.removed_pipelines.clear();
 
         let mut built_scene = None;
         let mut interner_updates = None;

webrender/src/scene_building.rs

@@ -449,8 +449,9 @@ impl<'a> SceneBuilder<'a> {
             device_pixel_scale,
         );
 
+        let cache = &root_pipeline.display_list_cache;
         builder.build_items(
-            &mut root_pipeline.display_list.iter(),
+            &mut root_pipeline.display_list.iter_with_cache(cache),
             root_pipeline.pipeline_id,
             true,
         );
@@ -687,30 +688,54 @@ impl<'a> SceneBuilder<'a> {
         apply_pipeline_clip: bool,
     ) {
         loop {
-            let subtraversal = {
-                let item = match traversal.next() {
-                    Some(item) => item,
-                    None => break,
-                };
+            let item = match traversal.next() {
+                Some(item) => item,
+                None => break,
+            };
 
-                match item.item() {
-                    DisplayItem::PopReferenceFrame |
-                    DisplayItem::PopStackingContext => return,
-                    _ => (),
+            let subtraversal = match item.item() {
+                DisplayItem::PushStackingContext(ref info) => {
+                    let space = self.get_space(&info.spatial_id);
+                    let mut subtraversal = item.sub_iter();
+                    self.build_stacking_context(
+                        &mut subtraversal,
+                        pipeline_id,
+                        &info.stacking_context,
+                        space,
+                        info.origin,
+                        item.filters(),
+                        &item.filter_datas(),
+                        item.filter_primitives(),
+                        info.prim_flags,
+                        apply_pipeline_clip,
+                    );
+                    Some(subtraversal)
                 }
-
-                self.build_item(
-                    item,
-                    pipeline_id,
-                    apply_pipeline_clip,
-                )
+                DisplayItem::PushReferenceFrame(ref info) => {
+                    let parent_space = self.get_space(&info.parent_spatial_id);
+                    let mut subtraversal = item.sub_iter();
+                    self.build_reference_frame(
+                        &mut subtraversal,
+                        pipeline_id,
+                        parent_space,
+                        info.origin,
+                        &info.reference_frame,
+                        apply_pipeline_clip,
+                    );
+                    Some(subtraversal)
+                }
+                DisplayItem::PopReferenceFrame |
+                DisplayItem::PopStackingContext => return,
+                _ => None,
             };
 
             // If build_item created a sub-traversal, we need `traversal` to have the
             // same state as the completed subtraversal, so we reinitialize it here.
             if let Some(mut subtraversal) = subtraversal {
                 subtraversal.merge_debug_stats_from(traversal);
                 *traversal = subtraversal;
+            } else {
+                self.build_item(item, pipeline_id, apply_pipeline_clip);
             }
         }
 
@@ -958,8 +983,10 @@ impl<'a> SceneBuilder<'a> {
 
         self.rf_mapper.push_scope();
         self.iframe_depth += 1;
+
+        let cache = &pipeline.display_list_cache;
         self.build_items(
-            &mut pipeline.display_list.iter(),
+            &mut pipeline.display_list.iter_with_cache(cache),
             pipeline.pipeline_id,
             true,
         );
@@ -1061,10 +1088,10 @@ impl<'a> SceneBuilder<'a> {
 
     fn build_item<'b>(
         &'b mut self,
-        item: DisplayItemRef<'a, 'b>,
+        item: DisplayItemRef,
         pipeline_id: PipelineId,
         apply_pipeline_clip: bool,
-    ) -> Option<BuiltDisplayListIter<'a>> {
+    ) {
         match *item.item() {
             DisplayItem::Image(ref info) => {
                 let (layout, _, clip_and_scroll) = self.process_common_properties_with_bounds(
@@ -1299,36 +1326,6 @@ impl<'a> SceneBuilder<'a> {
                     item.gradient_stops(),
                 );
             }
-            DisplayItem::PushStackingContext(ref info) => {
-                let space = self.get_space(&info.spatial_id);
-                let mut subtraversal = item.sub_iter();
-                self.build_stacking_context(
-                    &mut subtraversal,
-                    pipeline_id,
-                    &info.stacking_context,
-                    space,
-                    info.origin,
-                    item.filters(),
-                    item.filter_datas(),
-                    item.filter_primitives(),
-                    info.prim_flags,
-                    apply_pipeline_clip,
-                );
-                return Some(subtraversal);
-            }
-            DisplayItem::PushReferenceFrame(ref info) => {
-                let parent_space = self.get_space(&info.parent_spatial_id);
-                let mut subtraversal = item.sub_iter();
-                self.build_reference_frame(
-                    &mut subtraversal,
-                    pipeline_id,
-                    parent_space,
-                    info.origin,
-                    &info.reference_frame,
-                    apply_pipeline_clip,
-                );
-                return Some(subtraversal);
-            }
             DisplayItem::Iframe(ref info) => {
                 let space = self.get_space(&info.space_and_clip.spatial_id);
                 self.build_iframe(
@@ -1456,10 +1453,18 @@ impl<'a> SceneBuilder<'a> {
             DisplayItem::SetFilterData |
             DisplayItem::SetFilterPrimitives => {}
 
+            // Special items that are handled in the parent method
+            DisplayItem::PushStackingContext(..) |
+            DisplayItem::PushReferenceFrame(..) |
             DisplayItem::PopReferenceFrame |
             DisplayItem::PopStackingContext => {
                 unreachable!("Should have returned in parent method.")
             }
+
+            DisplayItem::ReuseItem(..) => {
+                unreachable!("Iterator logic error")
+            }
+
             DisplayItem::PushShadow(info) => {
                 let clip_and_scroll = self.get_clip_and_scroll(
                     &info.space_and_clip.clip_id,
@@ -1473,8 +1478,6 @@ impl<'a> SceneBuilder<'a> {
                 self.pop_all_shadows();
             }
         }
-
-        None
     }
 
     // Given a list of clip sources, a positioning node and

webrender_api/src/display_item.rs

@@ -33,6 +33,10 @@ pub const MAX_BLUR_RADIUS: f32 = 300.;
 /// events.
 pub type ItemTag = (u64, u16);
 
+/// An identifier used to refer to previously sent display items. Currently it
+/// refers to individual display items, but this may change later.
+pub type ItemKey = u16;
+
 bitflags! {
     #[repr(C)]
     #[derive(Deserialize, MallocSizeOf, Serialize, PeekPoke)]
@@ -74,6 +78,8 @@ pub struct CommonItemProperties {
     pub hit_info: Option<ItemTag>,
     /// Various flags describing properties of this primitive.
     pub flags: PrimitiveFlags,
+    /// The unique id of this display item.
+    pub item_key: Option<ItemKey>
 }
 
 impl CommonItemProperties {
@@ -88,6 +94,7 @@ impl CommonItemProperties {
             clip_id: space_and_clip.clip_id,
             hit_info: None,
             flags: PrimitiveFlags::default(),
+            item_key: None,
         }
     }
 }
@@ -156,6 +163,8 @@ pub enum DisplayItem {
     PopReferenceFrame,
     PopStackingContext,
     PopAllShadows,
+
+    ReuseItem(ItemKey),
 }
 
 /// This is a "complete" version of the DisplayItem, with all implicit trailing
@@ -196,6 +205,8 @@ pub enum DebugDisplayItem {
     PopReferenceFrame,
     PopStackingContext,
     PopAllShadows,
+
+    ReuseItem(ItemKey),
 }
 
 #[derive(Clone, Copy, Debug, Default, Deserialize, PartialEq, Serialize, PeekPoke)]
@@ -1469,6 +1480,7 @@ impl DisplayItem {
             DisplayItem::Rectangle(..) => "rectangle",
             DisplayItem::ScrollFrame(..) => "scroll_frame",
             DisplayItem::SetGradientStops => "set_gradient_stops",
+            DisplayItem::ReuseItem(..) => "reuse_item",
             DisplayItem::StickyFrame(..) => "sticky_frame",
             DisplayItem::Text(..) => "text",
             DisplayItem::YuvImage(..) => "yuv_image",