From 0abf027a0bf347b91639a6fcb72a8b56d3b04bb1 Mon Sep 17 00:00:00 2001
From: Martin Robinson <mrobinson@igalia.com>
Date: Fri, 30 May 2014 17:40:18 -0400
Subject: [PATCH] servo: Merge #2523 - Prevent child layers from overriding
 root background color (from mrobinson:background-color); r=pcwalton

The first layer implicitly provides the size of the page, but child
layer background colors can still improperly override the body
background color. This commit ensures that layer background colors only
apply to layers with the same id and pipeline id. Additionally the root
layer's unrendered color is defined by the first layer's background
color, just like for size.

Source-Repo: https://github.com/servo/servo
Source-Revision: 68e3fb26a701ae0224f579b66606118eab1eedaf
---
 .../components/main/compositing/compositor.rs   | 17 +++++++++--------
 .../main/compositing/compositor_layer.rs        | 14 ++++++++++++++
 .../main/compositing/compositor_task.rs         |  5 +++--
 3 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/servo/src/components/main/compositing/compositor.rs b/servo/src/components/main/compositing/compositor.rs
index 1422e8e51f5b..b14b5513bbf5 100644
--- a/servo/src/components/main/compositing/compositor.rs
+++ b/servo/src/components/main/compositing/compositor.rs
@@ -267,9 +267,9 @@ impl IOCompositor {
                     chan.send(Some(azure_hl::current_graphics_metadata()));
                 }
 
-                (Ok(CreateRootCompositorLayerIfNecessary(pipeline_id, layer_id, size)),
+                (Ok(CreateRootCompositorLayerIfNecessary(pipeline_id, layer_id, size, color)),
                  false) => {
-                    self.create_root_compositor_layer_if_necessary(pipeline_id, layer_id, size);
+                    self.create_root_compositor_layer_if_necessary(pipeline_id, layer_id, size, color);
                 }
 
                 (Ok(CreateDescendantCompositorLayerIfNecessary(pipeline_id,
@@ -322,12 +322,11 @@ impl IOCompositor {
         }
     }
 
-    // FIXME(#2004, pcwalton): Take the pipeline ID and layer ID into account.
-    fn set_unrendered_color(&mut self, _: PipelineId, _: LayerId, color: Color) {
+    fn set_unrendered_color(&mut self, pipeline_id: PipelineId, layer_id: LayerId, color: Color) {
         match self.compositor_layer {
-            Some(ref mut layer) => layer.unrendered_color = color,
-            None => {}
-        }
+            Some(ref mut layer) => layer.set_unrendered_color(pipeline_id, layer_id, color),
+            None => false,
+        };
     }
 
     fn set_ids(&mut self,
@@ -353,7 +352,8 @@ impl IOCompositor {
     fn create_root_compositor_layer_if_necessary(&mut self,
                                                  id: PipelineId,
                                                  layer_id: LayerId,
-                                                 size: Size2D<f32>) {
+                                                 size: Size2D<f32>,
+                                                 unrendered_color: Color) {
         let (root_pipeline, root_layer_id) = match self.compositor_layer {
             Some(ref compositor_layer) if compositor_layer.pipeline.id == id => {
                 (compositor_layer.pipeline.clone(), compositor_layer.id_of_first_child())
@@ -372,6 +372,7 @@ impl IOCompositor {
                                                           size,
                                                           self.opts.tile_size,
                                                           self.opts.cpu_painting);
+            new_layer.unrendered_color = unrendered_color;
 
             let first_child = self.root_layer.first_child.borrow().clone();
             match first_child {
diff --git a/servo/src/components/main/compositing/compositor_layer.rs b/servo/src/components/main/compositing/compositor_layer.rs
index 14c11fb9eda2..5e936a07227c 100644
--- a/servo/src/components/main/compositing/compositor_layer.rs
+++ b/servo/src/components/main/compositing/compositor_layer.rs
@@ -965,5 +965,19 @@ impl CompositorLayer {
     pub fn id_of_first_child(&self) -> LayerId {
         self.children.iter().next().expect("no first child!").child.id
     }
+
+    pub fn set_unrendered_color(&mut self, pipeline_id: PipelineId, layer_id: LayerId, color: Color) -> bool {
+        if self.pipeline.id != pipeline_id || self.id != layer_id {
+            for child_layer in self.children.mut_iter() {
+                if child_layer.child.set_unrendered_color(pipeline_id, layer_id, color) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        self.unrendered_color = color;
+        return true;
+    }
 }
 
diff --git a/servo/src/components/main/compositing/compositor_task.rs b/servo/src/components/main/compositing/compositor_task.rs
index 8891bb2575a8..009ab920b52b 100644
--- a/servo/src/components/main/compositing/compositor_task.rs
+++ b/servo/src/components/main/compositing/compositor_task.rs
@@ -96,7 +96,8 @@ impl RenderListener for CompositorChan {
             if first {
                 self.chan.send(CreateRootCompositorLayerIfNecessary(pipeline_id,
                                                                     metadata.id,
-                                                                    size));
+                                                                    size,
+                                                                    metadata.background_color));
                 first = false
             } else {
                 self.chan
@@ -166,7 +167,7 @@ pub enum Msg {
 
     /// Tells the compositor to create the root layer for a pipeline if necessary (i.e. if no layer
     /// with that ID exists).
-    CreateRootCompositorLayerIfNecessary(PipelineId, LayerId, Size2D<f32>),
+    CreateRootCompositorLayerIfNecessary(PipelineId, LayerId, Size2D<f32>, Color),
     /// Tells the compositor to create a descendant layer for a pipeline if necessary (i.e. if no
     /// layer with that ID exists).
     CreateDescendantCompositorLayerIfNecessary(PipelineId, LayerId, Rect<f32>, ScrollPolicy),