Split paint task messages from ScriptMsg

Refs: https://github.com/servo/servo/issues/8592

components/compositing/constellation.rs

@@ -27,6 +27,7 @@ use layout_traits::{LayoutControlChan, LayoutTaskFactory};
 use msg::compositor_msg::Epoch;
 use msg::constellation_msg::AnimationState;
 use msg::constellation_msg::CompositorMsg as FromCompositorMsg;
+use msg::constellation_msg::PaintMsg as FromPaintMsg;
 use msg::constellation_msg::ScriptMsg as FromScriptMsg;
 use msg::constellation_msg::WebDriverCommandMsg;
 use msg::constellation_msg::{FrameId, PipelineId};
@@ -86,12 +87,18 @@ pub struct Constellation<LTF, STF> {
     /// A channel through which compositor messages can be sent to this object.
     pub compositor_sender: Sender<FromCompositorMsg>,
 
+    /// A channel through which paint task messages can be sent to this object.
+    pub painter_sender: ConstellationChan<FromPaintMsg>,
+
     /// Receives messages from scripts.
     pub script_receiver: Receiver<FromScriptMsg>,
 
     /// Receives messages from the compositor
     pub compositor_receiver: Receiver<FromCompositorMsg>,
 
+    /// Receives messages from paint task.
+    pub painter_receiver: Receiver<FromPaintMsg>,
+
     /// A channel (the implementation of which is port-specific) through which messages can be sent
     /// to the compositor.
     pub compositor_proxy: Box<CompositorProxy>,
@@ -275,16 +282,19 @@ enum ChildProcess {
 impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
     pub fn start(state: InitialConstellationState) -> Sender<FromCompositorMsg> {
         let (ipc_script_receiver, ipc_script_sender) = ConstellationChan::<FromScriptMsg>::new();
-        //let (script_receiver, script_sender) = channel();
         let script_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_script_receiver);
         let (compositor_sender, compositor_receiver) = channel();
+        let (ipc_painter_receiver, ipc_painter_sender) = ConstellationChan::<FromPaintMsg>::new();
+        let painter_receiver = ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_painter_receiver);
         let compositor_sender_clone = compositor_sender.clone();
         spawn_named("Constellation".to_owned(), move || {
             let mut constellation: Constellation<LTF, STF> = Constellation {
                 script_sender: ipc_script_sender,
                 compositor_sender: compositor_sender_clone,
+                painter_sender: ipc_painter_sender,
                 script_receiver: script_receiver,
                 compositor_receiver: compositor_receiver,
+                painter_receiver: painter_receiver,
                 compositor_proxy: state.compositor_proxy,
                 devtools_chan: state.devtools_chan,
                 resource_task: state.resource_task,
@@ -357,6 +367,7 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
                 id: pipeline_id,
                 parent_info: parent_info,
                 constellation_chan: self.script_sender.clone(),
+                painter_chan: self.painter_sender.clone(),
                 scheduler_chan: self.scheduler_chan.clone(),
                 compositor_proxy: self.compositor_proxy.clone_compositor_proxy(),
                 devtools_chan: self.devtools_chan.clone(),
@@ -458,17 +469,21 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
     fn handle_request(&mut self) -> bool {
         enum Request {
             Script(FromScriptMsg),
-            Compositor(FromCompositorMsg)
+            Compositor(FromCompositorMsg),
+            Paint(FromPaintMsg)
         }
 
         let request = {
             let receiver_from_script = &self.script_receiver;
             let receiver_from_compositor = &self.compositor_receiver;
+            let receiver_from_paint = &self.painter_receiver;
             select! {
                 msg = receiver_from_script.recv() =>
                     Request::Script(msg.unwrap()),
                 msg = receiver_from_compositor.recv() =>
-                    Request::Compositor(msg.unwrap())
+                    Request::Compositor(msg.unwrap()),
+                msg = receiver_from_paint.recv() =>
+                    Request::Paint(msg.unwrap())
             }
         };
 
@@ -548,6 +563,7 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
 
 
             Request::Script(FromScriptMsg::Failure(Failure { pipeline_id, parent_info })) => {
+                debug!("handling script failure message from pipeline {:?}, {:?}", pipeline_id, parent_info);
                 self.handle_failure_msg(pipeline_id, parent_info);
             }
             Request::Script(FromScriptMsg::ScriptLoadedURLInIFrame(load_info)) => {
@@ -585,11 +601,6 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
                 debug!("constellation got navigation message from script");
                 self.handle_navigate_msg(pipeline_info, direction);
             }
-            // Notification that painting has finished and is requesting permission to paint.
-            Request::Script(FromScriptMsg::PainterReady(pipeline_id)) => {
-                debug!("constellation got painter ready message");
-                self.handle_painter_ready_msg(pipeline_id);
-            }
             Request::Script(FromScriptMsg::MozBrowserEvent(pipeline_id,
                                               subpage_id,
                                               event)) => {
@@ -647,6 +658,21 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
                 debug!("constellation got NodeStatus message");
                 self.compositor_proxy.send(ToCompositorMsg::Status(message));
             }
+
+
+            // Messages from paint task
+
+
+            // Notification that painting has finished and is requesting permission to paint.
+            Request::Paint(FromPaintMsg::Ready(pipeline_id)) => {
+                debug!("constellation got painter ready message");
+                self.handle_painter_ready_msg(pipeline_id);
+            }
+            Request::Paint(FromPaintMsg::Failure(Failure { pipeline_id, parent_info })) => {
+                debug!("handling paint failure message from pipeline {:?}, {:?}", pipeline_id, parent_info);
+                self.handle_failure_msg(pipeline_id, parent_info);
+            }
+
         }
         true
     }
@@ -669,8 +695,6 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
     fn handle_failure_msg(&mut self,
                           pipeline_id: PipelineId,
                           parent_info: Option<(PipelineId, SubpageId)>) {
-        debug!("handling failure message from pipeline {:?}, {:?}", pipeline_id, parent_info);
-
         if opts::get().hard_fail {
             // It's quite difficult to make Servo exit cleanly if some tasks have failed.
             // Hard fail exists for test runners so we crash and that's good enough.

components/compositing/pipeline.rs

@@ -15,6 +15,7 @@ use ipc_channel::router::ROUTER;
 use layers::geometry::DevicePixel;
 use layout_traits::{LayoutControlChan, LayoutTaskFactory};
 use msg::compositor_msg::ScriptToCompositorMsg;
+use msg::constellation_msg::PaintMsg;
 use msg::constellation_msg::ScriptMsg as ConstellationMsg;
 use msg::constellation_msg::{ConstellationChan, Failure, FrameId, PipelineId, SubpageId};
 use msg::constellation_msg::{LoadData, MozBrowserEvent, WindowSizeData};
@@ -81,6 +82,8 @@ pub struct InitialPipelineState {
     pub parent_info: Option<(PipelineId, SubpageId)>,
     /// A channel to the associated constellation.
     pub constellation_chan: ConstellationChan<ConstellationMsg>,
+    /// A channel to the associated paint task.
+    pub painter_chan: ConstellationChan<PaintMsg>,
     /// A channel to schedule timer events.
     pub scheduler_chan: IpcSender<TimerEventRequest>,
     /// A channel to the compositor.
@@ -226,6 +229,7 @@ impl Pipeline {
         let privileged_pipeline_content = PrivilegedPipelineContent {
             id: state.id,
             constellation_chan: state.constellation_chan,
+            painter_chan: state.painter_chan,
             compositor_proxy: state.compositor_proxy,
             font_cache_task: state.font_cache_task,
             time_profiler_chan: state.time_profiler_chan,
@@ -429,6 +433,7 @@ impl UnprivilegedPipelineContent {
 pub struct PrivilegedPipelineContent {
     id: PipelineId,
     constellation_chan: ConstellationChan<ConstellationMsg>,
+    painter_chan: ConstellationChan<PaintMsg>,
     compositor_proxy: Box<CompositorProxy + Send + 'static>,
     script_to_compositor_port: Option<IpcReceiver<ScriptToCompositorMsg>>,
     font_cache_task: FontCacheTask,
@@ -464,7 +469,7 @@ impl PrivilegedPipelineContent {
                           mem::replace(&mut self.layout_to_paint_port, None).unwrap(),
                           mem::replace(&mut self.chrome_to_paint_port, None).unwrap(),
                           self.compositor_proxy.clone_compositor_proxy(),
-                          self.constellation_chan.clone(),
+                          self.painter_chan.clone(),
                           self.font_cache_task.clone(),
                           self.failure.clone(),
                           self.time_profiler_chan.clone(),

components/gfx/paint_task.rs

@@ -21,7 +21,7 @@ use layers::layers::{BufferRequest, LayerBuffer, LayerBufferSet};
 use layers::platform::surface::{NativeDisplay, NativeSurface};
 use msg::compositor_msg::{Epoch, FrameTreeId, LayerId, LayerKind, LayerProperties};
 use msg::compositor_msg::{PaintListener, ScrollPolicy};
-use msg::constellation_msg::ScriptMsg as ConstellationMsg;
+use msg::constellation_msg::PaintMsg as ConstellationMsg;
 use msg::constellation_msg::{ConstellationChan, Failure, PipelineId};
 use paint_context::PaintContext;
 use profile_traits::mem::{self, ReportsChan};
@@ -330,7 +330,7 @@ impl<C> PaintTask<C> where C: PaintListener + Send + 'static {
                     if !self.paint_permission {
                         debug!("PaintTask: paint ready msg");
                         let ConstellationChan(ref mut c) = self.constellation_chan;
-                        c.send(ConstellationMsg::PainterReady(self.id)).unwrap();
+                        c.send(ConstellationMsg::Ready(self.id)).unwrap();
                         continue;
                     }
 
@@ -345,7 +345,7 @@ impl<C> PaintTask<C> where C: PaintListener + Send + 'static {
                     if !self.paint_permission {
                         debug!("PaintTask: paint ready msg");
                         let ConstellationChan(ref mut c) = self.constellation_chan;
-                        c.send(ConstellationMsg::PainterReady(self.id)).unwrap();
+                        c.send(ConstellationMsg::Ready(self.id)).unwrap();
                         continue;
                     }
 

components/msg/constellation_msg.rs

@@ -294,7 +294,6 @@ pub enum ScriptMsg {
     NewFavicon(Url),
     /// Status message to be displayed in the chrome, eg. a link URL on mouseover.
     NodeStatus(Option<String>),
-    PainterReady(PipelineId),
     /// Notification that this iframe should be removed.
     RemoveIFrame(PipelineId),
     ScriptLoadedURLInIFrame(IframeLoadInfo),
@@ -306,6 +305,13 @@ pub enum ScriptMsg {
     ViewportConstrained(PipelineId, ViewportConstraints),
 }
 
+/// Messages from the paint task to the constellation.
+#[derive(Deserialize, Serialize)]
+pub enum PaintMsg {
+    Ready(PipelineId),
+    Failure(Failure),
+}
+
 #[derive(Clone, Eq, PartialEq, Deserialize, Serialize, Debug)]
 pub enum AnimationState {
     AnimationsPresent,