servo: Merge #16184 - Terminate timer scheduler thread during shutdown (from ferjm:issue-16153-terminate-time-scheduler-shutdown); r=jdm

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #16153

Source-Repo: https://github.com/servo/servo
Source-Revision: a3d968833ba3653dd2b91f67adeb6c3faa1a256c

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 631cfd670d58fee87a345e2c4a25e3c92e3805a1

servo/components/constellation/constellation.rs

@@ -96,7 +96,7 @@ use profile_traits::time;
 use script_traits::{AnimationState, AnimationTickType, CompositorEvent};
 use script_traits::{ConstellationControlMsg, ConstellationMsg as FromCompositorMsg, DiscardBrowsingContext};
 use script_traits::{DocumentActivity, DocumentState, LayoutControlMsg, LoadData};
-use script_traits::{IFrameLoadInfo, IFrameLoadInfoWithData, IFrameSandboxState, TimerEventRequest};
+use script_traits::{IFrameLoadInfo, IFrameLoadInfoWithData, IFrameSandboxState, TimerSchedulerMsg};
 use script_traits::{LayoutMsg as FromLayoutMsg, ScriptMsg as FromScriptMsg, ScriptThreadFactory};
 use script_traits::{LogEntry, ServiceWorkerMsg, webdriver_msg};
 use script_traits::{MozBrowserErrorType, MozBrowserEvent, WebDriverCommandMsg, WindowSizeData};
@@ -214,7 +214,7 @@ pub struct Constellation<Message, LTF, STF> {
 
     /// A channel for the constellation to send messages to the
     /// timer thread.
-    scheduler_chan: IpcSender<TimerEventRequest>,
+    scheduler_chan: IpcSender<TimerSchedulerMsg>,
 
     /// A channel for the constellation to send messages to the
     /// Webrender thread.
@@ -1241,6 +1241,11 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
             }
         }
 
+        debug!("Exiting timer scheduler.");
+        if let Err(e) = self.scheduler_chan.send(TimerSchedulerMsg::Exit) {
+            warn!("Exit timer scheduler failed ({})", e);
+        }
+
         debug!("Exiting font cache thread.");
         self.font_cache_thread.exit();
 

servo/components/constellation/pipeline.rs

@@ -25,7 +25,7 @@ use script_traits::{ConstellationControlMsg, DevicePixel, DiscardBrowsingContext
 use script_traits::{DocumentActivity, InitialScriptState};
 use script_traits::{LayoutControlMsg, LayoutMsg, LoadData, MozBrowserEvent};
 use script_traits::{NewLayoutInfo, SWManagerMsg, SWManagerSenders, ScriptMsg};
-use script_traits::{ScriptThreadFactory, TimerEventRequest, WindowSizeData};
+use script_traits::{ScriptThreadFactory, TimerSchedulerMsg, WindowSizeData};
 use servo_config::opts::{self, Opts};
 use servo_config::prefs::{PREFS, Pref};
 use servo_url::ServoUrl;
@@ -121,7 +121,7 @@ pub struct InitialPipelineState {
     pub layout_to_constellation_chan: IpcSender<LayoutMsg>,
 
     /// A channel to schedule timer events.
-    pub scheduler_chan: IpcSender<TimerEventRequest>,
+    pub scheduler_chan: IpcSender<TimerSchedulerMsg>,
 
     /// A channel to the compositor.
     pub compositor_proxy: Box<CompositorProxy + 'static + Send>,
@@ -445,7 +445,7 @@ pub struct UnprivilegedPipelineContent {
     parent_info: Option<(PipelineId, FrameType)>,
     constellation_chan: IpcSender<ScriptMsg>,
     layout_to_constellation_chan: IpcSender<LayoutMsg>,
-    scheduler_chan: IpcSender<TimerEventRequest>,
+    scheduler_chan: IpcSender<TimerSchedulerMsg>,
     devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
     bluetooth_thread: IpcSender<BluetoothRequest>,
     swmanager_thread: IpcSender<SWManagerMsg>,

servo/components/constellation/timer_scheduler.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use ipc_channel::ipc::{self, IpcSender};
-use script_traits::{TimerEvent, TimerEventRequest};
+use script_traits::{TimerEvent, TimerEventRequest, TimerSchedulerMsg};
 use std::cmp::{self, Ord};
 use std::collections::BinaryHeap;
 use std::sync::mpsc;
@@ -38,7 +38,7 @@ impl PartialEq for ScheduledEvent {
 }
 
 impl TimerScheduler {
-    pub fn start() -> IpcSender<TimerEventRequest> {
+    pub fn start() -> IpcSender<TimerSchedulerMsg> {
         let (req_ipc_sender, req_ipc_receiver) = ipc::channel().expect("Channel creation failed.");
         let (req_sender, req_receiver) = mpsc::sync_channel(1);
 
@@ -72,7 +72,7 @@ impl TimerScheduler {
                     // Look to see if there are any incoming events
                     match req_receiver.try_recv() {
                         // If there is an event, add it to the priority queue
-                        Ok(req) => {
+                        Ok(TimerSchedulerMsg::Request(req)) => {
                             let TimerEventRequest(_, _, _, delay) = req;
                             let schedule = Instant::now() + Duration::from_millis(delay.get());
                             let event = ScheduledEvent { request: req, for_time: schedule };
@@ -85,7 +85,8 @@ impl TimerScheduler {
                             None => thread::park(),
                             Some(event) => thread::park_timeout(event.for_time - now),
                         },
-                        // If the channel is closed, we are done.
+                        // If the channel is closed or we are shutting down, we are done.
+                        Ok(TimerSchedulerMsg::Exit) |
                         Err(Disconnected) => break,
                     }
                 }
@@ -105,8 +106,16 @@ impl TimerScheduler {
             .name(String::from("TimerProxy"))
             .spawn(move || {
                 while let Ok(req) = req_ipc_receiver.recv() {
+                    let mut shutting_down = false;
+                    match req {
+                        TimerSchedulerMsg::Exit => shutting_down = true,
+                        _ => {}
+                    }
                     let _ = req_sender.send(req);
                     timeout_thread.unpark();
+                    if shutting_down {
+                        break;
+                    }
                 }
                 // This thread can terminate if the req_ipc_sender is dropped.
                 warn!("TimerProxy thread terminated.");

servo/components/script/dom/globalscope.rs

@@ -37,7 +37,7 @@ use profile_traits::{mem, time};
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort};
 use script_thread::{MainThreadScriptChan, RunnableWrapper, ScriptThread};
 use script_traits::{MsDuration, ScriptMsg as ConstellationMsg, TimerEvent};
-use script_traits::{TimerEventId, TimerEventRequest, TimerSource};
+use script_traits::{TimerEventId, TimerSchedulerMsg, TimerSource};
 use servo_url::ServoUrl;
 use std::cell::Cell;
 use std::collections::HashMap;
@@ -82,7 +82,7 @@ pub struct GlobalScope {
     constellation_chan: IpcSender<ConstellationMsg>,
 
     #[ignore_heap_size_of = "channels are hard"]
-    scheduler_chan: IpcSender<TimerEventRequest>,
+    scheduler_chan: IpcSender<TimerSchedulerMsg>,
 
     /// https://html.spec.whatwg.org/multipage/#in-error-reporting-mode
     in_error_reporting_mode: Cell<bool>,
@@ -101,7 +101,7 @@ impl GlobalScope {
             mem_profiler_chan: mem::ProfilerChan,
             time_profiler_chan: time::ProfilerChan,
             constellation_chan: IpcSender<ConstellationMsg>,
-            scheduler_chan: IpcSender<TimerEventRequest>,
+            scheduler_chan: IpcSender<TimerSchedulerMsg>,
             resource_threads: ResourceThreads,
             timer_event_chan: IpcSender<TimerEvent>)
             -> Self {
@@ -229,7 +229,7 @@ impl GlobalScope {
         &self.constellation_chan
     }
 
-    pub fn scheduler_chan(&self) -> &IpcSender<TimerEventRequest> {
+    pub fn scheduler_chan(&self) -> &IpcSender<TimerSchedulerMsg> {
         &self.scheduler_chan
     }
 

servo/components/script/dom/window.rs

@@ -80,7 +80,7 @@ use script_thread::{MainThreadScriptChan, MainThreadScriptMsg, Runnable, Runnabl
 use script_thread::{SendableMainThreadScriptChan, ImageCacheMsg};
 use script_traits::{ConstellationControlMsg, LoadData, MozBrowserEvent, UntrustedNodeAddress};
 use script_traits::{DocumentState, TimerEvent, TimerEventId};
-use script_traits::{ScriptMsg as ConstellationMsg, TimerEventRequest, WindowSizeData, WindowSizeType};
+use script_traits::{ScriptMsg as ConstellationMsg, TimerSchedulerMsg, WindowSizeData, WindowSizeType};
 use script_traits::webdriver_msg::{WebDriverJSError, WebDriverJSResult};
 use servo_atoms::Atom;
 use servo_config::opts;
@@ -1711,7 +1711,7 @@ impl Window {
                devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
                constellation_chan: IpcSender<ConstellationMsg>,
                control_chan: IpcSender<ConstellationControlMsg>,
-               scheduler_chan: IpcSender<TimerEventRequest>,
+               scheduler_chan: IpcSender<TimerSchedulerMsg>,
                timer_event_chan: IpcSender<TimerEvent>,
                layout_chan: Sender<Msg>,
                id: PipelineId,

servo/components/script/script_thread.rs

@@ -86,7 +86,7 @@ use script_traits::{CompositorEvent, ConstellationControlMsg};
 use script_traits::{DocumentActivity, DiscardBrowsingContext, EventResult};
 use script_traits::{InitialScriptState, LayoutMsg, LoadData, MouseButton, MouseEventType, MozBrowserEvent};
 use script_traits::{NewLayoutInfo, ScriptMsg as ConstellationMsg};
-use script_traits::{ScriptThreadFactory, TimerEvent, TimerEventRequest, TimerSource};
+use script_traits::{ScriptThreadFactory, TimerEvent, TimerSchedulerMsg, TimerSource};
 use script_traits::{TouchEventType, TouchId, UntrustedNodeAddress, WindowSizeData, WindowSizeType};
 use script_traits::CompositorEvent::{KeyEvent, MouseButtonEvent, MouseMoveEvent, ResizeEvent};
 use script_traits::CompositorEvent::{TouchEvent, TouchpadPressureEvent};
@@ -472,7 +472,7 @@ pub struct ScriptThread {
     /// List of pipelines that have been owned and closed by this script thread.
     closed_pipelines: DOMRefCell<HashSet<PipelineId>>,
 
-    scheduler_chan: IpcSender<TimerEventRequest>,
+    scheduler_chan: IpcSender<TimerSchedulerMsg>,
     timer_event_chan: Sender<TimerEvent>,
     timer_event_port: Receiver<TimerEvent>,
 

servo/components/script/timers.rs

@@ -18,7 +18,8 @@ use ipc_channel::ipc::IpcSender;
 use js::jsapi::{HandleValue, Heap};
 use js::jsval::{JSVal, UndefinedValue};
 use script_traits::{MsDuration, precise_time_ms};
-use script_traits::{TimerEvent, TimerEventId, TimerEventRequest, TimerSource};
+use script_traits::{TimerEvent, TimerEventId, TimerEventRequest};
+use script_traits::{TimerSchedulerMsg, TimerSource};
 use servo_config::prefs::PREFS;
 use std::cell::Cell;
 use std::cmp::{self, Ord, Ordering};
@@ -35,7 +36,7 @@ pub struct OneshotTimers {
     #[ignore_heap_size_of = "Defined in std"]
     timer_event_chan: IpcSender<TimerEvent>,
     #[ignore_heap_size_of = "Defined in std"]
-    scheduler_chan: IpcSender<TimerEventRequest>,
+    scheduler_chan: IpcSender<TimerSchedulerMsg>,
     next_timer_handle: Cell<OneshotTimerHandle>,
     timers: DOMRefCell<Vec<OneshotTimer>>,
     suspended_since: Cell<Option<MsDuration>>,
@@ -109,7 +110,7 @@ impl PartialEq for OneshotTimer {
 
 impl OneshotTimers {
     pub fn new(timer_event_chan: IpcSender<TimerEvent>,
-               scheduler_chan: IpcSender<TimerEventRequest>)
+               scheduler_chan: IpcSender<TimerSchedulerMsg>)
                -> OneshotTimers {
         OneshotTimers {
             js_timers: JsTimers::new(),
@@ -267,7 +268,7 @@ impl OneshotTimers {
             let delay = Length::new(timer.scheduled_for.get().saturating_sub(precise_time_ms().get()));
             let request = TimerEventRequest(self.timer_event_chan.clone(), timer.source,
                                             expected_event_id, delay);
-            self.scheduler_chan.send(request).unwrap();
+            self.scheduler_chan.send(TimerSchedulerMsg::Request(request)).unwrap();
         }
     }
 

servo/components/script_traits/lib.rs

@@ -416,6 +416,15 @@ pub enum TouchpadPressurePhase {
 #[derive(Deserialize, Serialize)]
 pub struct TimerEventRequest(pub IpcSender<TimerEvent>, pub TimerSource, pub TimerEventId, pub MsDuration);
 
+/// Type of messages that can be sent to the timer scheduler.
+#[derive(Deserialize, Serialize)]
+pub enum TimerSchedulerMsg {
+    /// Message to schedule a new timer event.
+    Request(TimerEventRequest),
+    /// Message to exit the timer scheduler.
+    Exit,
+}
+
 /// Notifies the script thread to fire due timers.
 /// `TimerSource` must be `FromWindow` when dispatched to `ScriptThread` and
 /// must be `FromWorker` when dispatched to a `DedicatedGlobalWorkerScope`
@@ -479,7 +488,7 @@ pub struct InitialScriptState {
     /// A sender for the layout thread to communicate to the constellation.
     pub layout_to_constellation_chan: IpcSender<LayoutMsg>,
     /// A channel to schedule timer events.
-    pub scheduler_chan: IpcSender<TimerEventRequest>,
+    pub scheduler_chan: IpcSender<TimerSchedulerMsg>,
     /// A channel to the resource manager thread.
     pub resource_threads: ResourceThreads,
     /// A channel to the bluetooth thread.
@@ -770,7 +779,7 @@ pub struct WorkerGlobalScopeInit {
     /// Messages to send to constellation
     pub constellation_chan: IpcSender<ScriptMsg>,
     /// Message to send to the scheduler
-    pub scheduler_chan: IpcSender<TimerEventRequest>,
+    pub scheduler_chan: IpcSender<TimerSchedulerMsg>,
     /// The worker id
     pub worker_id: WorkerId,
     /// The pipeline id