servo: Merge #7450 - Ordering guarantees for timers (from benschulz:constellation-timer); r=jdm

This is an rough solution to the issue described in #3396. XHRs still do their own thing and an overall clean up is in order. Before I do that, though, I'd really like someone to sign off on the overall idea.

There's one major difference to what jdm layed out #3396: The timers remain with the window/worker and only the earliest expiring one is coordinated with the dedicated timer thread.
That means both the timer thread and the window/worker have to keep track of which timer expires next, which feels a bit wonky. However, the upshot is that there's no need for communication with the timer thread when a pipeline is frozen, thawed or dropped.

Most relvant parts are
 - the [`TimerScheduler`](6f5f661958 (diff-74137a6f50ab38e7a1e4d16920a66ce7R73)), which is the new per-constellation timer task and
 - the [`ActiveTimers`](6f5f661958 (diff-86707d952414a2860b78bcf6c1db8e2eR34)) which is what's left on the window/worker side.

Source-Repo: https://github.com/servo/servo
Source-Revision: 2de5407cdabef67ed03b2ad4edf4a22541d77875

servo/components/compositing/constellation.rs

@@ -41,6 +41,7 @@ use profile_traits::mem;
 use profile_traits::time;
 use script_traits::{CompositorEvent, ConstellationControlMsg, LayoutControlMsg};
 use script_traits::{ScriptState, ScriptTaskFactory};
+use script_traits::{TimerEventRequest};
 use std::borrow::ToOwned;
 use std::collections::HashMap;
 use std::io::{self, Write};
@@ -49,6 +50,7 @@ use std::mem::replace;
 use std::process;
 use std::sync::mpsc::{Receiver, Sender, channel};
 use style_traits::viewport::ViewportConstraints;
+use timer_scheduler::TimerScheduler;
 use url::Url;
 use util::cursor::Cursor;
 use util::geometry::PagePx;
@@ -135,6 +137,8 @@ pub struct Constellation<LTF, STF> {
 
     /// A list of in-process senders to `WebGLPaintTask`s.
     webgl_paint_tasks: Vec<Sender<CanvasMsg>>,
+
+    scheduler_chan: Sender<TimerEventRequest>,
 }
 
 /// State needed to construct a constellation.
@@ -280,6 +284,7 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
                 webdriver: WebDriverData::new(),
                 canvas_paint_tasks: Vec::new(),
                 webgl_paint_tasks: Vec::new(),
+                scheduler_chan: TimerScheduler::start(),
             };
             let namespace_id = constellation.next_pipeline_namespace_id();
             PipelineNamespace::install(namespace_id);
@@ -317,6 +322,7 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
                 id: pipeline_id,
                 parent_info: parent_info,
                 constellation_chan: self.chan.clone(),
+                scheduler_chan: self.scheduler_chan.clone(),
                 compositor_proxy: self.compositor_proxy.clone_compositor_proxy(),
                 devtools_chan: self.devtools_chan.clone(),
                 image_cache_task: self.image_cache_task.clone(),

servo/components/compositing/lib.rs

@@ -6,6 +6,7 @@
 #![feature(iter_cmp)]
 #![feature(slice_bytes)]
 #![feature(vec_push_all)]
+#![feature(mpsc_select)]
 #![feature(plugin)]
 #![plugin(plugins)]
 
@@ -54,6 +55,7 @@ mod compositor_layer;
 mod headless;
 mod scrolling;
 mod surface_map;
+mod timer_scheduler;
 pub mod compositor_task;
 pub mod constellation;
 pub mod pipeline;

servo/components/compositing/pipeline.rs

@@ -24,6 +24,7 @@ use profile_traits::mem as profile_mem;
 use profile_traits::time;
 use script_traits::{ConstellationControlMsg, InitialScriptState};
 use script_traits::{LayoutControlMsg, NewLayoutInfo, ScriptTaskFactory};
+use script_traits::{TimerEventRequest};
 use std::any::Any;
 use std::mem;
 use std::sync::mpsc::{Receiver, Sender, channel};
@@ -75,6 +76,8 @@ pub struct InitialPipelineState {
     pub parent_info: Option<(PipelineId, SubpageId)>,
     /// A channel to the associated constellation.
     pub constellation_chan: ConstellationChan,
+    /// A channel to schedule timer events.
+    pub scheduler_chan: Sender<TimerEventRequest>,
     /// A channel to the compositor.
     pub compositor_proxy: Box<CompositorProxy + 'static + Send>,
     /// A channel to the developer tools, if applicable.
@@ -181,6 +184,7 @@ impl Pipeline {
             id: state.id,
             parent_info: state.parent_info,
             constellation_chan: state.constellation_chan,
+            scheduler_chan: state.scheduler_chan,
             compositor_proxy: state.compositor_proxy,
             devtools_chan: script_to_devtools_chan,
             image_cache_task: state.image_cache_task,
@@ -316,6 +320,7 @@ pub struct PipelineContent {
     id: PipelineId,
     parent_info: Option<(PipelineId, SubpageId)>,
     constellation_chan: ConstellationChan,
+    scheduler_chan: Sender<TimerEventRequest>,
     compositor_proxy: Box<CompositorProxy + Send + 'static>,
     devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
     image_cache_task: ImageCacheTask,
@@ -361,6 +366,7 @@ impl PipelineContent {
             control_chan: self.script_chan.clone(),
             control_port: mem::replace(&mut self.script_port, None).unwrap(),
             constellation_chan: self.constellation_chan.clone(),
+            scheduler_chan: self.scheduler_chan.clone(),
             failure_info: self.failure.clone(),
             resource_task: self.resource_task,
             storage_task: self.storage_task.clone(),

servo/components/compositing/timer_scheduler.rs

@@ -0,0 +1,221 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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 euclid::length::Length;
+use num::traits::Saturating;
+use script_traits::{MsDuration, NsDuration, precise_time_ms, precise_time_ns};
+use script_traits::{TimerEvent, TimerEventRequest};
+use std::cell::RefCell;
+use std::cmp::{self, Ord};
+use std::collections::BinaryHeap;
+use std::sync::Arc;
+use std::sync::atomic::{self, AtomicBool};
+use std::sync::mpsc::{channel, Receiver, Select, Sender};
+use std::thread::{self, spawn, Thread};
+use util::task::spawn_named;
+
+/// A quick hack to work around the removal of [`std::old_io::timer::Timer`](
+/// http://doc.rust-lang.org/1.0.0-beta/std/old_io/timer/struct.Timer.html )
+struct CancelableOneshotTimer {
+    thread: Thread,
+    canceled: Arc<AtomicBool>,
+    port: Receiver<()>,
+}
+
+impl CancelableOneshotTimer {
+    fn new(duration: MsDuration) -> CancelableOneshotTimer {
+        let (tx, rx) = channel();
+        let canceled = Arc::new(AtomicBool::new(false));
+        let canceled_clone = canceled.clone();
+
+        let thread = spawn(move || {
+            let due_time = precise_time_ms() + duration;
+
+            let mut park_time = duration;
+
+            loop {
+                thread::park_timeout_ms(park_time.get() as u32);
+
+                if canceled_clone.load(atomic::Ordering::Relaxed) {
+                    return;
+                }
+
+                // park_timeout_ms does not guarantee parking for the
+                // given amout. We might have woken up early.
+                let current_time = precise_time_ms();
+                if current_time >= due_time {
+                    let _ = tx.send(());
+                    return;
+                }
+                park_time = due_time - current_time;
+            }
+        }).thread().clone();
+
+        CancelableOneshotTimer {
+            thread: thread,
+            canceled: canceled,
+            port: rx,
+        }
+    }
+
+    fn port(&self) -> &Receiver<()> {
+        &self.port
+    }
+
+    fn cancel(&self) {
+        self.canceled.store(true, atomic::Ordering::Relaxed);
+        self.thread.unpark();
+    }
+}
+
+pub struct TimerScheduler {
+    port: Receiver<TimerEventRequest>,
+
+    scheduled_events: RefCell<BinaryHeap<ScheduledEvent>>,
+
+    timer: RefCell<Option<CancelableOneshotTimer>>,
+}
+
+struct ScheduledEvent {
+    request: TimerEventRequest,
+    for_time: NsDuration,
+}
+
+impl Ord for ScheduledEvent {
+    fn cmp(&self, other: &ScheduledEvent) -> cmp::Ordering {
+        self.for_time.cmp(&other.for_time).reverse()
+    }
+}
+
+impl PartialOrd for ScheduledEvent {
+    fn partial_cmp(&self, other: &ScheduledEvent) -> Option<cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Eq for ScheduledEvent {}
+impl PartialEq for ScheduledEvent {
+    fn eq(&self, other: &ScheduledEvent) -> bool {
+        self as *const ScheduledEvent == other as *const ScheduledEvent
+    }
+}
+
+enum Task {
+    HandleRequest(TimerEventRequest),
+    DispatchDueEvents,
+}
+
+impl TimerScheduler {
+    pub fn start() -> Sender<TimerEventRequest> {
+        let (chan, port) = channel();
+
+        let timer_scheduler = TimerScheduler {
+            port: port,
+
+            scheduled_events: RefCell::new(BinaryHeap::new()),
+
+            timer: RefCell::new(None),
+        };
+
+        spawn_named("TimerScheduler".to_owned(), move || {
+            timer_scheduler.run_event_loop();
+        });
+
+        chan
+    }
+
+    fn run_event_loop(&self) {
+        loop {
+            match self.receive_next_task() {
+                Some(Task::HandleRequest(request)) => self.handle_request(request),
+                Some(Task::DispatchDueEvents) => self.dispatch_due_events(),
+                None => break,
+            }
+        }
+    }
+
+    #[allow(unsafe_code)]
+    fn receive_next_task(&self) -> Option<Task> {
+        let port = &self.port;
+        let timer = self.timer.borrow();
+        let timer_port = timer.as_ref().map(|timer| timer.port());
+
+        if let Some(ref timer_port) = timer_port {
+            let sel = Select::new();
+            let mut scheduler_handle = sel.handle(port);
+            let mut timer_handle = sel.handle(timer_port);
+
+            unsafe {
+                scheduler_handle.add();
+                timer_handle.add();
+            }
+
+            let ret = sel.wait();
+            if ret == scheduler_handle.id() {
+                port.recv().ok().map(|req| Task::HandleRequest(req))
+            } else if ret == timer_handle.id() {
+                timer_port.recv().ok().map(|_| Task::DispatchDueEvents)
+            } else {
+                panic!("unexpected select result!")
+            }
+        } else {
+            port.recv().ok().map(|req| Task::HandleRequest(req))
+        }
+    }
+
+    fn handle_request(&self, request: TimerEventRequest) {
+        let TimerEventRequest(_, _, _, duration_ms) = request;
+        let duration_ns = Length::new(duration_ms.get() * 1000 * 1000);
+        let schedule_for = precise_time_ns() + duration_ns;
+
+        let previously_earliest = self.scheduled_events.borrow().peek()
+                .map(|scheduled| scheduled.for_time)
+                .unwrap_or(Length::new(u64::max_value()));
+
+        self.scheduled_events.borrow_mut().push(ScheduledEvent {
+            request: request,
+            for_time: schedule_for,
+        });
+
+        if schedule_for < previously_earliest {
+            self.start_timer_for_next_event();
+        }
+    }
+
+    fn dispatch_due_events(&self) {
+        let now = precise_time_ns();
+
+        {
+            let mut events = self.scheduled_events.borrow_mut();
+
+            while !events.is_empty() && events.peek().as_ref().unwrap().for_time <= now {
+                let event = events.pop().unwrap();
+                let TimerEventRequest(chan, source, id, _) = event.request;
+
+                let _ = chan.send(TimerEvent(source, id));
+            }
+        }
+
+        self.start_timer_for_next_event();
+    }
+
+    fn start_timer_for_next_event(&self) {
+        let events = self.scheduled_events.borrow();
+        let next_event = events.peek();
+
+        let mut timer = self.timer.borrow_mut();
+
+        if let Some(ref mut timer) = *timer {
+            timer.cancel();
+        }
+
+        *timer = next_event.map(|next_event| {
+            let delay_ns = next_event.for_time.get().saturating_sub(precise_time_ns().get());
+            // Round up, we'd rather be late than early…
+            let delay_ms = Length::new(delay_ns.saturating_add(999999) / (1000 * 1000));
+
+            CancelableOneshotTimer::new(delay_ms)
+        });
+    }
+}

servo/components/profile/time.rs

@@ -92,6 +92,7 @@ impl Formattable for ProfilerCategory {
             ProfilerCategory::ScriptEvent => "Script Event",
             ProfilerCategory::ScriptUpdateReplacedElement => "Script Update Replaced Element",
             ProfilerCategory::ScriptSetViewport => "Script Set Viewport",
+            ProfilerCategory::ScriptTimerEvent => "Script Timer Event",
             ProfilerCategory::ScriptWebSocketEvent => "Script Web Socket Event",
             ProfilerCategory::ScriptWorkerEvent => "Script Worker Event",
             ProfilerCategory::ScriptXhrEvent => "Script Xhr Event",

servo/components/profile_traits/time.rs

@@ -70,6 +70,7 @@ pub enum ProfilerCategory {
     ScriptEvent,
     ScriptUpdateReplacedElement,
     ScriptSetViewport,
+    ScriptTimerEvent,
     ScriptWebSocketEvent,
     ScriptWorkerEvent,
     ScriptXhrEvent,

servo/components/script/dom/bindings/global.rs

@@ -22,6 +22,8 @@ use msg::constellation_msg::{ConstellationChan, PipelineId, WorkerId};
 use net_traits::ResourceTask;
 use profile_traits::mem;
 use script_task::{CommonScriptMsg, ScriptChan, ScriptPort, ScriptTask};
+use script_traits::TimerEventRequest;
+use std::sync::mpsc::Sender;
 use url::Url;
 use util::mem::HeapSizeOf;
 
@@ -96,6 +98,14 @@ impl<'a> GlobalRef<'a> {
         }
     }
 
+    /// Get the scheduler channel to request timer events.
+    pub fn scheduler_chan(&self) -> Sender<TimerEventRequest> {
+        match *self {
+            GlobalRef::Window(window) => window.scheduler_chan(),
+            GlobalRef::Worker(worker) => worker.scheduler_chan(),
+        }
+    }
+
     /// Get an `IpcSender<ScriptToDevtoolsControlMsg>` to send messages to Devtools
     /// task when available.
     pub fn devtools_chan(&self) -> Option<IpcSender<ScriptToDevtoolsControlMsg>> {

servo/components/script/dom/bindings/trace.rs

@@ -37,6 +37,7 @@ use dom::bindings::js::{JS, Root};
 use dom::bindings::refcounted::Trusted;
 use dom::bindings::utils::{Reflectable, Reflector, WindowProxyHandler};
 use encoding::types::EncodingRef;
+use euclid::length::Length as EuclidLength;
 use euclid::matrix2d::Matrix2D;
 use euclid::rect::Rect;
 use euclid::size::Size2D;
@@ -58,7 +59,7 @@ use net_traits::storage_task::StorageType;
 use profile_traits::mem::ProfilerChan as MemProfilerChan;
 use profile_traits::time::ProfilerChan as TimeProfilerChan;
 use script_task::ScriptChan;
-use script_traits::UntrustedNodeAddress;
+use script_traits::{TimerEventChan, TimerEventId, TimerSource, UntrustedNodeAddress};
 use selectors::parser::PseudoElement;
 use serde::{Deserialize, Serialize};
 use smallvec::SmallVec;
@@ -283,6 +284,7 @@ no_jsmanaged_fields!(HashSet<T>);
 // These three are interdependent, if you plan to put jsmanaged data
 // in one of these make sure it is propagated properly to containing structs
 no_jsmanaged_fields!(SubpageId, WindowSizeData, PipelineId);
+no_jsmanaged_fields!(TimerEventId, TimerSource);
 no_jsmanaged_fields!(WorkerId);
 no_jsmanaged_fields!(QuirksMode);
 no_jsmanaged_fields!(Runtime);
@@ -293,6 +295,7 @@ no_jsmanaged_fields!(WindowProxyHandler);
 no_jsmanaged_fields!(UntrustedNodeAddress);
 no_jsmanaged_fields!(LengthOrPercentageOrAuto);
 no_jsmanaged_fields!(RGBA);
+no_jsmanaged_fields!(EuclidLength<Unit, T>);
 no_jsmanaged_fields!(Matrix2D<T>);
 no_jsmanaged_fields!(StorageType);
 no_jsmanaged_fields!(CanvasGradientStop, LinearGradientStyle, RadialGradientStyle);
@@ -311,6 +314,13 @@ impl JSTraceable for Box<ScriptChan + Send> {
     }
 }
 
+impl JSTraceable for Box<TimerEventChan + Send> {
+    #[inline]
+    fn trace(&self, _trc: *mut JSTracer) {
+        // Do nothing
+    }
+}
+
 impl JSTraceable for Box<FnBox(f64, )> {
     #[inline]
     fn trace(&self, _trc: *mut JSTracer) {

servo/components/script/dom/dedicatedworkerglobalscope.rs

@@ -29,7 +29,8 @@ use msg::constellation_msg::PipelineId;
 use net_traits::load_whole_resource;
 use rand::random;
 use script_task::ScriptTaskEventCategory::WorkerEvent;
-use script_task::{CommonScriptMsg, ScriptChan, ScriptPort, ScriptTask, StackRootTLS, TimerSource};
+use script_task::{ScriptTask, ScriptChan, ScriptPort, StackRootTLS, CommonScriptMsg};
+use script_traits::{TimerEvent, TimerEventChan, TimerSource};
 use std::mem::replace;
 use std::rc::Rc;
 use std::sync::mpsc::{Receiver, RecvError, Select, Sender, channel};
@@ -101,6 +102,29 @@ impl ScriptPort for Receiver<(TrustedWorkerAddress, WorkerScriptMsg)> {
     }
 }
 
+/// A TimerEventChan that can be cloned freely and will silently send a TrustedWorkerAddress
+/// with timer events. While this SendableWorkerScriptChan is alive, the associated Worker
+/// object will remain alive.
+struct WorkerThreadTimerEventChan {
+    sender: Sender<(TrustedWorkerAddress, TimerEvent)>,
+    worker: TrustedWorkerAddress,
+}
+
+impl TimerEventChan for WorkerThreadTimerEventChan {
+    fn send(&self, event: TimerEvent) -> Result<(), ()> {
+        self.sender
+            .send((self.worker.clone(), event))
+            .map_err(|_| ())
+    }
+
+    fn clone(&self) -> Box<TimerEventChan + Send> {
+        box WorkerThreadTimerEventChan {
+            sender: self.sender.clone(),
+            worker: self.worker.clone(),
+        }
+    }
+}
+
 /// Set the `worker` field of a related DedicatedWorkerGlobalScope object to a particular
 /// value for the duration of this object's lifetime. This ensures that the related Worker
 /// object only lives as long as necessary (ie. while events are being executed), while
@@ -127,6 +151,7 @@ impl<'a> Drop for AutoWorkerReset<'a> {
 
 enum MixedMessage {
     FromWorker((TrustedWorkerAddress, WorkerScriptMsg)),
+    FromScheduler((TrustedWorkerAddress, TimerEvent)),
     FromDevtools(DevtoolScriptControlMsg),
 }
 
@@ -139,6 +164,8 @@ pub struct DedicatedWorkerGlobalScope {
     receiver: Receiver<(TrustedWorkerAddress, WorkerScriptMsg)>,
     #[ignore_heap_size_of = "Defined in std"]
     own_sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>,
+    #[ignore_heap_size_of = "Defined in std"]
+    timer_event_port: Receiver<(TrustedWorkerAddress, TimerEvent)>,
     #[ignore_heap_size_of = "Trusted<T> has unclear ownership like JS<T>"]
     worker: DOMRefCell<Option<TrustedWorkerAddress>>,
     #[ignore_heap_size_of = "Can't measure trait objects"]
@@ -154,14 +181,18 @@ impl DedicatedWorkerGlobalScope {
                      runtime: Rc<Runtime>,
                      parent_sender: Box<ScriptChan + Send>,
                      own_sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>,
-                     receiver: Receiver<(TrustedWorkerAddress, WorkerScriptMsg)>)
+                     receiver: Receiver<(TrustedWorkerAddress, WorkerScriptMsg)>,
+                     timer_event_chan: Box<TimerEventChan + Send>,
+                     timer_event_port: Receiver<(TrustedWorkerAddress, TimerEvent)>)
                      -> DedicatedWorkerGlobalScope {
+
         DedicatedWorkerGlobalScope {
             workerglobalscope: WorkerGlobalScope::new_inherited(
-                init, worker_url, runtime, from_devtools_receiver),
+                init, worker_url, runtime, from_devtools_receiver, timer_event_chan),
             id: id,
             receiver: receiver,
             own_sender: own_sender,
+            timer_event_port: timer_event_port,
             parent_sender: parent_sender,
             worker: DOMRefCell::new(None),
         }
@@ -174,11 +205,13 @@ impl DedicatedWorkerGlobalScope {
                runtime: Rc<Runtime>,
                parent_sender: Box<ScriptChan + Send>,
                own_sender: Sender<(TrustedWorkerAddress, WorkerScriptMsg)>,
-               receiver: Receiver<(TrustedWorkerAddress, WorkerScriptMsg)>)
+               receiver: Receiver<(TrustedWorkerAddress, WorkerScriptMsg)>,
+               timer_event_chan: Box<TimerEventChan + Send>,
+               timer_event_port: Receiver<(TrustedWorkerAddress, TimerEvent)>)
                -> Root<DedicatedWorkerGlobalScope> {
         let scope = box DedicatedWorkerGlobalScope::new_inherited(
             init, worker_url, id, from_devtools_receiver, runtime.clone(), parent_sender,
-            own_sender, receiver);
+            own_sender, receiver, timer_event_chan, timer_event_port);
         DedicatedWorkerGlobalScopeBinding::Wrap(runtime.cx(), scope)
     }
 
@@ -214,9 +247,16 @@ impl DedicatedWorkerGlobalScope {
             let (devtools_mpsc_chan, devtools_mpsc_port) = channel();
             ROUTER.route_ipc_receiver_to_mpsc_sender(from_devtools_receiver, devtools_mpsc_chan);
 
+            let (timer_tx, timer_rx) = channel();
+            let timer_event_chan = box WorkerThreadTimerEventChan {
+                sender: timer_tx,
+                worker: worker.clone(),
+            };
+
             let global = DedicatedWorkerGlobalScope::new(
                 init, url, id, devtools_mpsc_port, runtime.clone(),
-                parent_sender.clone(), own_sender, receiver);
+                parent_sender.clone(), own_sender, receiver,
+                timer_event_chan, timer_rx);
             // FIXME(njn): workers currently don't have a unique ID suitable for using in reporter
             // registration (#6631), so we instead use a random number and cross our fingers.
             let scope = global.upcast::<WorkerGlobalScope>();
@@ -263,13 +303,16 @@ impl DedicatedWorkerGlobalScope {
     fn receive_event(&self) -> Result<MixedMessage, RecvError> {
         let scope = self.upcast::<WorkerGlobalScope>();
         let worker_port = &self.receiver;
+        let timer_event_port = &self.timer_event_port;
         let devtools_port = scope.from_devtools_receiver();
 
         let sel = Select::new();
         let mut worker_handle = sel.handle(worker_port);
+        let mut timer_event_handle = sel.handle(timer_event_port);
         let mut devtools_handle = sel.handle(devtools_port);
         unsafe {
             worker_handle.add();
+            timer_event_handle.add();
             if scope.from_devtools_sender().is_some() {
                 devtools_handle.add();
             }
@@ -277,6 +320,8 @@ impl DedicatedWorkerGlobalScope {
         let ret = sel.wait();
         if ret == worker_handle.id() {
             Ok(MixedMessage::FromWorker(try!(worker_port.recv())))
+        } else if ret == timer_event_handle.id() {
+            Ok(MixedMessage::FromScheduler(try!(timer_event_port.recv())))
         } else if ret == devtools_handle.id() {
             Ok(MixedMessage::FromDevtools(try!(devtools_port.recv())))
         } else {
@@ -301,11 +346,6 @@ impl DedicatedWorkerGlobalScope {
             WorkerScriptMsg::Common(CommonScriptMsg::RefcountCleanup(addr)) => {
                 LiveDOMReferences::cleanup(addr);
             },
-            WorkerScriptMsg::Common(
-                CommonScriptMsg::FireTimer(TimerSource::FromWorker, timer_id)) => {
-                let scope = self.upcast::<WorkerGlobalScope>();
-                scope.handle_fire_timer(timer_id);
-            },
             WorkerScriptMsg::Common(CommonScriptMsg::CollectReports(reports_chan)) => {
                 let scope = self.upcast::<WorkerGlobalScope>();
                 let cx = scope.get_cx();
@@ -313,9 +353,6 @@ impl DedicatedWorkerGlobalScope {
                 let reports = ScriptTask::get_reports(cx, path_seg);
                 reports_chan.send(reports);
             },
-            WorkerScriptMsg::Common(CommonScriptMsg::FireTimer(_, _)) => {
-                panic!("obtained a fire timeout from window for the worker!")
-            },
         }
     }
 
@@ -333,6 +370,18 @@ impl DedicatedWorkerGlobalScope {
                     _ => debug!("got an unusable devtools control message inside the worker!"),
                 }
             },
+            MixedMessage::FromScheduler((linked_worker, timer_event)) => {
+                match timer_event {
+                    TimerEvent(TimerSource::FromWorker, id) => {
+                        let _ar = AutoWorkerReset::new(self, linked_worker);
+                        let scope = self.upcast::<WorkerGlobalScope>();
+                        scope.handle_fire_timer(id);
+                    },
+                    TimerEvent(_, _) => {
+                        panic!("A worker received a TimerEvent from a window.")
+                    }
+                }
+            }
             MixedMessage::FromWorker((linked_worker, msg)) => {
                 let _ar = AutoWorkerReset::new(self, linked_worker);
                 self.handle_script_event(msg);

servo/components/script/dom/window.rs

@@ -52,9 +52,9 @@ use num::traits::ToPrimitive;
 use page::Page;
 use profile_traits::mem;
 use rustc_serialize::base64::{FromBase64, STANDARD, ToBase64};
-use script_task::{MainThreadScriptChan, SendableMainThreadScriptChan};
-use script_task::{MainThreadScriptMsg, ScriptChan, ScriptPort, TimerSource};
-use script_traits::ConstellationControlMsg;
+use script_task::{ScriptChan, ScriptPort, MainThreadScriptMsg};
+use script_task::{SendableMainThreadScriptChan, MainThreadScriptChan, MainThreadTimerEventChan};
+use script_traits::{ConstellationControlMsg, TimerEventChan, TimerEventId, TimerEventRequest, TimerSource};
 use selectors::parser::PseudoElement;
 use std::ascii::AsciiExt;
 use std::borrow::ToOwned;
@@ -70,7 +70,7 @@ use std::sync::mpsc::TryRecvError::{Disconnected, Empty};
 use std::sync::mpsc::{Receiver, Sender, channel};
 use string_cache::Atom;
 use time;
-use timers::{IsInterval, TimerCallback, TimerId, TimerManager};
+use timers::{ActiveTimers, IsInterval, TimerCallback};
 use url::Url;
 use util::geometry::{self, MAX_RECT};
 use util::str::{DOMString, HTML_SPACE_CHARACTERS};
@@ -129,7 +129,9 @@ pub struct Window {
     screen: MutNullableHeap<JS<Screen>>,
     session_storage: MutNullableHeap<JS<Storage>>,
     local_storage: MutNullableHeap<JS<Storage>>,
-    timers: TimerManager,
+    #[ignore_heap_size_of = "channels are hard"]
+    scheduler_chan: Sender<TimerEventRequest>,
+    timers: ActiveTimers,
 
     next_worker_id: Cell<WorkerId>,
 
@@ -425,8 +427,7 @@ impl WindowMethods for Window {
                                             args,
                                             timeout,
                                             IsInterval::NonInterval,
-                                            TimerSource::FromWindow(self.id.clone()),
-                                            self.script_chan.clone())
+                                            TimerSource::FromWindow(self.id.clone()))
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-settimeout
@@ -435,8 +436,7 @@ impl WindowMethods for Window {
                                             args,
                                             timeout,
                                             IsInterval::NonInterval,
-                                            TimerSource::FromWindow(self.id.clone()),
-                                            self.script_chan.clone())
+                                            TimerSource::FromWindow(self.id.clone()))
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-cleartimeout
@@ -450,8 +450,7 @@ impl WindowMethods for Window {
                                             args,
                                             timeout,
                                             IsInterval::Interval,
-                                            TimerSource::FromWindow(self.id.clone()),
-                                            self.script_chan.clone())
+                                            TimerSource::FromWindow(self.id.clone()))
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-setinterval
@@ -460,8 +459,7 @@ impl WindowMethods for Window {
                                             args,
                                             timeout,
                                             IsInterval::Interval,
-                                            TimerSource::FromWindow(self.id.clone()),
-                                            self.script_chan.clone())
+                                            TimerSource::FromWindow(self.id.clone()))
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-clearinterval
@@ -1076,7 +1074,7 @@ impl Window {
             MainThreadScriptMsg::Navigate(self.id, LoadData::new(url))).unwrap();
     }
 
-    pub fn handle_fire_timer(&self, timer_id: TimerId) {
+    pub fn handle_fire_timer(&self, timer_id: TimerEventId) {
         self.timers.fire_timer(timer_id, self);
         self.reflow(ReflowGoal::ForDisplay, ReflowQueryType::NoQuery, ReflowReason::Timer);
     }
@@ -1122,6 +1120,10 @@ impl Window {
         self.constellation_chan.clone()
     }
 
+    pub fn scheduler_chan(&self) -> Sender<TimerEventRequest> {
+        self.scheduler_chan.clone()
+    }
+
     pub fn windowproxy_handler(&self) -> WindowProxyHandler {
         WindowProxyHandler(self.dom_static.windowproxy_handler.0)
     }
@@ -1267,6 +1269,8 @@ impl Window {
                mem_profiler_chan: mem::ProfilerChan,
                devtools_chan: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
                constellation_chan: ConstellationChan,
+               scheduler_chan: Sender<TimerEventRequest>,
+               timer_event_chan: MainThreadTimerEventChan,
                layout_chan: LayoutChan,
                id: PipelineId,
                parent_info: Option<(PipelineId, SubpageId)>,
@@ -1299,7 +1303,8 @@ impl Window {
             screen: Default::default(),
             session_storage: Default::default(),
             local_storage: Default::default(),
-            timers: TimerManager::new(),
+            scheduler_chan: scheduler_chan.clone(),
+            timers: ActiveTimers::new(box timer_event_chan, scheduler_chan),
             next_worker_id: Cell::new(WorkerId(0)),
             id: id,
             parent_info: parent_info,

servo/components/script/dom/worker.rs

@@ -72,6 +72,7 @@ impl Worker {
 
         let resource_task = global.resource_task();
         let constellation_chan = global.constellation_chan();
+        let scheduler_chan = global.scheduler_chan();
 
         let (sender, receiver) = channel();
         let worker = Worker::new(global, sender.clone());
@@ -101,6 +102,7 @@ impl Worker {
             to_devtools_sender: global.devtools_chan(),
             from_devtools_sender: optional_sender,
             constellation_chan: constellation_chan,
+            scheduler_chan: scheduler_chan,
             worker_id: worker_id,
         };
         DedicatedWorkerGlobalScope::run_worker_scope(

servo/components/script/dom/workerglobalscope.rs

@@ -23,12 +23,13 @@ use js::rust::Runtime;
 use msg::constellation_msg::{ConstellationChan, PipelineId, WorkerId};
 use net_traits::{ResourceTask, load_whole_resource};
 use profile_traits::mem;
-use script_task::{CommonScriptMsg, ScriptChan, ScriptPort, TimerSource};
+use script_task::{CommonScriptMsg, ScriptChan, ScriptPort};
+use script_traits::{TimerEventChan, TimerEventId, TimerEventRequest, TimerSource};
 use std::cell::Cell;
 use std::default::Default;
 use std::rc::Rc;
-use std::sync::mpsc::Receiver;
-use timers::{IsInterval, TimerCallback, TimerId, TimerManager};
+use std::sync::mpsc::{Receiver, Sender};
+use timers::{ActiveTimers, IsInterval, TimerCallback};
 use url::{Url, UrlParser};
 use util::str::DOMString;
 
@@ -43,6 +44,7 @@ pub struct WorkerGlobalScopeInit {
     pub to_devtools_sender: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
     pub from_devtools_sender: Option<IpcSender<DevtoolScriptControlMsg>>,
     pub constellation_chan: ConstellationChan,
+    pub scheduler_chan: Sender<TimerEventRequest>,
     pub worker_id: WorkerId,
 }
 
@@ -61,7 +63,7 @@ pub struct WorkerGlobalScope {
     navigator: MutNullableHeap<JS<WorkerNavigator>>,
     console: MutNullableHeap<JS<Console>>,
     crypto: MutNullableHeap<JS<Crypto>>,
-    timers: TimerManager,
+    timers: ActiveTimers,
     #[ignore_heap_size_of = "Defined in std"]
     mem_profiler_chan: mem::ProfilerChan,
     #[ignore_heap_size_of = "Defined in ipc-channel"]
@@ -83,13 +85,17 @@ pub struct WorkerGlobalScope {
 
     #[ignore_heap_size_of = "Defined in std"]
     constellation_chan: ConstellationChan,
+
+    #[ignore_heap_size_of = "Defined in std"]
+    scheduler_chan: Sender<TimerEventRequest>,
 }
 
 impl WorkerGlobalScope {
     pub fn new_inherited(init: WorkerGlobalScopeInit,
                          worker_url: Url,
                          runtime: Rc<Runtime>,
-                         from_devtools_receiver: Receiver<DevtoolScriptControlMsg>)
+                         from_devtools_receiver: Receiver<DevtoolScriptControlMsg>,
+                         timer_event_chan: Box<TimerEventChan + Send>)
                          -> WorkerGlobalScope {
         WorkerGlobalScope {
             eventtarget: EventTarget::new_inherited(),
@@ -102,13 +108,14 @@ impl WorkerGlobalScope {
             navigator: Default::default(),
             console: Default::default(),
             crypto: Default::default(),
-            timers: TimerManager::new(),
+            timers: ActiveTimers::new(timer_event_chan, init.scheduler_chan.clone()),
             mem_profiler_chan: init.mem_profiler_chan,
             to_devtools_sender: init.to_devtools_sender,
             from_devtools_sender: init.from_devtools_sender,
             from_devtools_receiver: from_devtools_receiver,
             devtools_wants_updates: Cell::new(false),
             constellation_chan: init.constellation_chan,
+            scheduler_chan: init.scheduler_chan,
         }
     }
 
@@ -132,6 +139,10 @@ impl WorkerGlobalScope {
         self.constellation_chan.clone()
     }
 
+    pub fn scheduler_chan(&self) -> Sender<TimerEventRequest> {
+        self.scheduler_chan.clone()
+    }
+
     pub fn get_cx(&self) -> *mut JSContext {
         self.runtime.cx()
     }
@@ -233,8 +244,7 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
                                             args,
                                             timeout,
                                             IsInterval::NonInterval,
-                                            TimerSource::FromWorker,
-                                            self.script_chan())
+                                            TimerSource::FromWorker)
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-setinterval
@@ -243,8 +253,7 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
                                             args,
                                             timeout,
                                             IsInterval::NonInterval,
-                                            TimerSource::FromWorker,
-                                            self.script_chan())
+                                            TimerSource::FromWorker)
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-clearinterval
@@ -258,8 +267,7 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
                                             args,
                                             timeout,
                                             IsInterval::Interval,
-                                            TimerSource::FromWorker,
-                                            self.script_chan())
+                                            TimerSource::FromWorker)
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-setinterval
@@ -268,8 +276,7 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
                                             args,
                                             timeout,
                                             IsInterval::Interval,
-                                            TimerSource::FromWorker,
-                                            self.script_chan())
+                                            TimerSource::FromWorker)
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowtimers-clearinterval
@@ -330,7 +337,7 @@ impl WorkerGlobalScope {
         }
     }
 
-    pub fn handle_fire_timer(&self, timer_id: TimerId) {
+    pub fn handle_fire_timer(&self, timer_id: TimerEventId) {
         self.timers.fire_timer(timer_id, self);
     }
 

servo/components/script/horribly_inefficient_timers.rs

@@ -1,31 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * 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/. */
-
-/// A quick hack to work around the removal of [`std::old_io::timer::Timer`](
-/// http://doc.rust-lang.org/1.0.0-beta/std/old_io/timer/struct.Timer.html )
-
-use std::sync::mpsc::{Receiver, channel};
-use std::thread::{sleep_ms, spawn};
-
-pub fn oneshot(duration_ms: u32) -> Receiver<()> {
-    let (tx, rx) = channel();
-    spawn(move || {
-        sleep_ms(duration_ms);
-        let _ = tx.send(());
-    });
-    rx
-}
-
-pub fn periodic(duration_ms: u32) -> Receiver<()> {
-    let (tx, rx) = channel();
-    spawn(move || {
-        loop {
-            sleep_ms(duration_ms);
-            if tx.send(()).is_err() {
-                break
-            }
-        }
-    });
-    rx
-}

servo/components/script/lib.rs

@@ -86,7 +86,6 @@ mod devtools;
 pub mod document_loader;
 #[macro_use]
 pub mod dom;
-mod horribly_inefficient_timers;
 pub mod layout_interface;
 mod mem;
 mod network_listener;

servo/components/script/script_task.rs

@@ -82,6 +82,7 @@ use script_traits::CompositorEvent::{MouseDownEvent, MouseUpEvent};
 use script_traits::{CompositorEvent, ConstellationControlMsg};
 use script_traits::{InitialScriptState, MouseButton, NewLayoutInfo};
 use script_traits::{OpaqueScriptLayoutChannel, ScriptState, ScriptTaskFactory};
+use script_traits::{TimerEvent, TimerEventChan, TimerEventRequest, TimerSource};
 use std::any::Any;
 use std::borrow::ToOwned;
 use std::cell::{Cell, RefCell};
@@ -96,7 +97,6 @@ use std::sync::mpsc::{Receiver, Select, Sender, channel};
 use std::sync::{Arc, Mutex};
 use string_cache::Atom;
 use time::{Tm, now};
-use timers::TimerId;
 use url::{Url, UrlParser};
 use util::opts;
 use util::str::DOMString;
@@ -156,12 +156,6 @@ impl InProgressLoad {
     }
 }
 
-#[derive(Copy, Clone)]
-pub enum TimerSource {
-    FromWindow(PipelineId),
-    FromWorker
-}
-
 pub trait Runnable {
     fn handler(self: Box<Self>);
 }
@@ -175,6 +169,7 @@ enum MixedMessage {
     FromScript(MainThreadScriptMsg),
     FromDevtools(DevtoolScriptControlMsg),
     FromImageCache(ImageCacheResult),
+    FromScheduler(TimerEvent),
 }
 
 /// Common messages used to control the event loops in both the script and the worker
@@ -182,10 +177,6 @@ pub enum CommonScriptMsg {
     /// Requests that the script task measure its memory usage. The results are sent back via the
     /// supplied channel.
     CollectReports(ReportsChan),
-    /// Fires a JavaScript timeout
-    /// TimerSource must be FromWindow when dispatched to ScriptTask and
-    /// must be FromWorker when dispatched to a DedicatedGlobalWorkerScope
-    FireTimer(TimerSource, TimerId),
     /// A DOM object's last pinned reference was removed (dispatched to all tasks).
     RefcountCleanup(TrustedReference),
     /// Generic message that encapsulates event handling.
@@ -205,6 +196,7 @@ pub enum ScriptTaskEventCategory {
     NetworkEvent,
     Resize,
     ScriptEvent,
+    TimerEvent,
     UpdateReplacedElement,
     SetViewport,
     WebSocketEvent,
@@ -327,6 +319,20 @@ impl MainThreadScriptChan {
     }
 }
 
+pub struct MainThreadTimerEventChan(Sender<TimerEvent>);
+
+impl TimerEventChan for MainThreadTimerEventChan {
+    fn send(&self, event: TimerEvent) -> Result<(), ()> {
+        let MainThreadTimerEventChan(ref chan) = *self;
+        chan.send(event).map_err(|_| ())
+    }
+
+    fn clone(&self) -> Box<TimerEventChan + Send> {
+        let MainThreadTimerEventChan(ref chan) = *self;
+        box MainThreadTimerEventChan((*chan).clone())
+    }
+}
+
 pub struct StackRootTLS;
 
 impl StackRootTLS {
@@ -408,6 +414,10 @@ pub struct ScriptTask {
 
     /// List of pipelines that have been owned and closed by this script task.
     closed_pipelines: RefCell<HashSet<PipelineId>>,
+
+    scheduler_chan: Sender<TimerEventRequest>,
+    timer_event_chan: Sender<TimerEvent>,
+    timer_event_port: Receiver<TimerEvent>,
 }
 
 /// In the event of task failure, all data on the stack runs its destructor. However, there
@@ -604,6 +614,8 @@ impl ScriptTask {
         let image_cache_port =
             ROUTER.route_ipc_receiver_to_new_mpsc_receiver(ipc_image_cache_port);
 
+        let (timer_event_chan, timer_event_port) = channel();
+
         ScriptTask {
             page: DOMRefCell::new(None),
             incomplete_loads: DOMRefCell::new(vec!()),
@@ -631,6 +643,10 @@ impl ScriptTask {
             js_runtime: Rc::new(runtime),
             mouse_over_targets: DOMRefCell::new(vec!()),
             closed_pipelines: RefCell::new(HashSet::new()),
+
+            scheduler_chan: state.scheduler_chan,
+            timer_event_chan: timer_event_chan,
+            timer_event_port: timer_event_port,
         }
     }
 
@@ -717,26 +733,30 @@ impl ScriptTask {
         // Receive at least one message so we don't spinloop.
         let mut event = {
             let sel = Select::new();
-            let mut port1 = sel.handle(&self.port);
-            let mut port2 = sel.handle(&self.control_port);
-            let mut port3 = sel.handle(&self.devtools_port);
-            let mut port4 = sel.handle(&self.image_cache_port);
+            let mut script_port = sel.handle(&self.port);
+            let mut control_port = sel.handle(&self.control_port);
+            let mut timer_event_port = sel.handle(&self.timer_event_port);
+            let mut devtools_port = sel.handle(&self.devtools_port);
+            let mut image_cache_port = sel.handle(&self.image_cache_port);
             unsafe {
-                port1.add();
-                port2.add();
+                script_port.add();
+                control_port.add();
+                timer_event_port.add();
                 if self.devtools_chan.is_some() {
-                    port3.add();
+                    devtools_port.add();
                 }
-                port4.add();
+                image_cache_port.add();
             }
             let ret = sel.wait();
-            if ret == port1.id() {
+            if ret == script_port.id() {
                 MixedMessage::FromScript(self.port.recv().unwrap())
-            } else if ret == port2.id() {
+            } else if ret == control_port.id() {
                 MixedMessage::FromConstellation(self.control_port.recv().unwrap())
-            } else if ret == port3.id() {
+            } else if ret == timer_event_port.id() {
+                MixedMessage::FromScheduler(self.timer_event_port.recv().unwrap())
+            } else if ret == devtools_port.id() {
                 MixedMessage::FromDevtools(self.devtools_port.recv().unwrap())
-            } else if ret == port4.id() {
+            } else if ret == image_cache_port.id() {
                 MixedMessage::FromImageCache(self.image_cache_port.recv().unwrap())
             } else {
                 panic!("unexpected select result")
@@ -797,12 +817,15 @@ impl ScriptTask {
             // on and execute the sequential non-resize events we've seen.
             match self.control_port.try_recv() {
                 Err(_) => match self.port.try_recv() {
-                    Err(_) => match self.devtools_port.try_recv() {
-                        Err(_) => match self.image_cache_port.try_recv() {
-                            Err(_) => break,
-                            Ok(ev) => event = MixedMessage::FromImageCache(ev),
+                    Err(_) => match self.timer_event_port.try_recv() {
+                        Err(_) => match self.devtools_port.try_recv() {
+                            Err(_) => match self.image_cache_port.try_recv() {
+                                Err(_) => break,
+                                Ok(ev) => event = MixedMessage::FromImageCache(ev),
+                            },
+                            Ok(ev) => event = MixedMessage::FromDevtools(ev),
                         },
-                        Ok(ev) => event = MixedMessage::FromDevtools(ev),
+                        Ok(ev) => event = MixedMessage::FromScheduler(ev),
                     },
                     Ok(ev) => event = MixedMessage::FromScript(ev),
                 },
@@ -823,6 +846,7 @@ impl ScriptTask {
                     },
                     MixedMessage::FromConstellation(inner_msg) => self.handle_msg_from_constellation(inner_msg),
                     MixedMessage::FromScript(inner_msg) => self.handle_msg_from_script(inner_msg),
+                    MixedMessage::FromScheduler(inner_msg) => self.handle_timer_event(inner_msg),
                     MixedMessage::FromDevtools(inner_msg) => self.handle_msg_from_devtools(inner_msg),
                     MixedMessage::FromImageCache(inner_msg) => self.handle_msg_from_image_cache(inner_msg),
                 }
@@ -871,7 +895,8 @@ impl ScriptTask {
                         *category,
                     _ => ScriptTaskEventCategory::ScriptEvent
                 }
-            }
+            },
+            MixedMessage::FromScheduler(_) => ScriptTaskEventCategory::TimerEvent,
         }
     }
 
@@ -893,6 +918,7 @@ impl ScriptTask {
                 ScriptTaskEventCategory::ScriptEvent => ProfilerCategory::ScriptEvent,
                 ScriptTaskEventCategory::UpdateReplacedElement => ProfilerCategory::ScriptUpdateReplacedElement,
                 ScriptTaskEventCategory::SetViewport => ProfilerCategory::ScriptSetViewport,
+                ScriptTaskEventCategory::TimerEvent => ProfilerCategory::ScriptTimerEvent,
                 ScriptTaskEventCategory::WebSocketEvent => ProfilerCategory::ScriptWebSocketEvent,
                 ScriptTaskEventCategory::WorkerEvent => ProfilerCategory::ScriptWorkerEvent,
                 ScriptTaskEventCategory::XhrEvent => ProfilerCategory::ScriptXhrEvent,
@@ -966,12 +992,6 @@ impl ScriptTask {
                 runnable.handler(self),
             MainThreadScriptMsg::DocumentLoadsComplete(id) =>
                 self.handle_loads_complete(id),
-            MainThreadScriptMsg::Common(
-                CommonScriptMsg::FireTimer(TimerSource::FromWindow(id), timer_id)) =>
-                self.handle_fire_timer_msg(id, timer_id),
-            MainThreadScriptMsg::Common(
-                CommonScriptMsg::FireTimer(TimerSource::FromWorker, _)) =>
-                panic!("Worker timeouts must not be sent to script task"),
             MainThreadScriptMsg::Common(CommonScriptMsg::RunnableMsg(_, runnable)) =>
                 // The category of the runnable is ignored by the pattern, however
                 // it is still respected by profiling (see categorize_msg).
@@ -983,6 +1003,22 @@ impl ScriptTask {
         }
     }
 
+    fn handle_timer_event(&self, timer_event: TimerEvent) {
+        let TimerEvent(source, id) = timer_event;
+
+        let pipeline_id = match source {
+            TimerSource::FromWindow(pipeline_id) => pipeline_id,
+            TimerSource::FromWorker => panic!("Worker timeouts must not be sent to script task"),
+        };
+
+        let page = self.root_page();
+        let page = page.find(pipeline_id).expect("ScriptTask: received fire timer msg for a
+            pipeline ID not associated with this script task. This is a bug.");
+        let window = page.window();
+
+        window.r().handle_fire_timer(id);
+    }
+
     fn handle_msg_from_devtools(&self, msg: DevtoolScriptControlMsg) {
         let page = self.root_page();
         match msg {
@@ -1272,15 +1308,6 @@ impl ScriptTask {
         reports_chan.send(reports);
     }
 
-    /// Handles a timer that fired.
-    fn handle_fire_timer_msg(&self, id: PipelineId, timer_id: TimerId) {
-        let page = self.root_page();
-        let page = page.find(id).expect("ScriptTask: received fire timer msg for a
-            pipeline ID not associated with this script task. This is a bug.");
-        let window = page.window();
-        window.r().handle_fire_timer(timer_id);
-    }
-
     /// Handles freeze message
     fn handle_freeze_msg(&self, id: PipelineId) {
         // Workaround for a race condition when navigating before the initial page has
@@ -1587,6 +1614,8 @@ impl ScriptTask {
                                  self.mem_profiler_chan.clone(),
                                  self.devtools_chan.clone(),
                                  self.constellation_chan.clone(),
+                                 self.scheduler_chan.clone(),
+                                 MainThreadTimerEventChan(self.timer_event_chan.clone()),
                                  incomplete.layout_chan,
                                  incomplete.pipeline_id,
                                  incomplete.parent_info,

servo/components/script/timers.rs

@@ -8,81 +8,63 @@ use dom::bindings::codegen::Bindings::FunctionBinding::Function;
 use dom::bindings::global::global_object_for_js_object;
 use dom::bindings::utils::Reflectable;
 use dom::window::ScriptHelpers;
-use horribly_inefficient_timers;
+use euclid::length::Length;
 use js::jsapi::{HandleValue, Heap, RootedValue};
 use js::jsval::{JSVal, UndefinedValue};
-use script_task::{CommonScriptMsg, ScriptChan, TimerSource};
-use std::borrow::ToOwned;
+use num::traits::Saturating;
+use script_traits::{MsDuration, precise_time_ms};
+use script_traits::{TimerEventChan, TimerEventId, TimerEventRequest, TimerSource};
 use std::cell::Cell;
-use std::cmp;
-use std::collections::HashMap;
+use std::cmp::{self, Ord, Ordering};
 use std::default::Default;
-use std::hash::{Hash, Hasher};
 use std::rc::Rc;
-use std::sync::mpsc::Select;
-use std::sync::mpsc::{Sender, channel};
+use std::sync::mpsc::Sender;
 use util::mem::HeapSizeOf;
 use util::str::DOMString;
-use util::task::spawn_named;
 
-#[derive(JSTraceable, PartialEq, Eq, Copy, Clone, HeapSizeOf)]
-pub struct TimerId(i32);
+#[derive(JSTraceable, PartialEq, Eq, Copy, Clone, HeapSizeOf, Hash, PartialOrd, Ord)]
+pub struct TimerHandle(i32);
 
 #[derive(JSTraceable, HeapSizeOf)]
 #[privatize]
-struct TimerHandle {
-    handle: TimerId,
-    data: TimerData,
-    #[ignore_heap_size_of = "channels are hard"]
-    control_chan: Option<Sender<TimerControlMsg>>,
-}
-
-#[derive(JSTraceable, Clone)]
-pub enum TimerCallback {
-    StringTimerCallback(DOMString),
-    FunctionTimerCallback(Rc<Function>)
-}
-
-impl HeapSizeOf for TimerCallback {
-    fn heap_size_of_children(&self) -> usize {
-        // FIXME: Rc<T> isn't HeapSizeOf and we can't ignore it due to #6870 and #6871
-        0
-    }
-}
-
-impl Hash for TimerId {
-    fn hash<H: Hasher>(&self, state: &mut H) {
-        let TimerId(id) = *self;
-        id.hash(state);
-    }
-}
-
-impl TimerHandle {
-    fn cancel(&mut self) {
-        self.control_chan.as_ref().map(|chan| chan.send(TimerControlMsg::Cancel).ok());
-    }
-    fn suspend(&mut self) {
-        self.control_chan.as_ref().map(|chan| chan.send(TimerControlMsg::Suspend).ok());
-    }
-    fn resume(&mut self) {
-        self.control_chan.as_ref().map(|chan| chan.send(TimerControlMsg::Resume).ok());
-    }
+pub struct ActiveTimers {
+    #[ignore_heap_size_of = "Defined in std"]
+    timer_event_chan: Box<TimerEventChan + Send>,
+    #[ignore_heap_size_of = "Defined in std"]
+    scheduler_chan: Sender<TimerEventRequest>,
+    next_timer_handle: Cell<TimerHandle>,
+    timers: DOMRefCell<Vec<Timer>>,
+    suspended_since: Cell<Option<MsDuration>>,
+    /// Initially 0, increased whenever the associated document is reactivated
+    /// by the amount of ms the document was inactive. The current time can be
+    /// offset back by this amount for a coherent time across document
+    /// activations.
+    suspension_offset: Cell<MsDuration>,
+    /// Calls to `fire_timer` with a different argument than this get ignored.
+    /// They were previously scheduled and got invalidated when
+    ///  - timers were suspended,
+    ///  - the timer it was scheduled for got canceled or
+    ///  - a timer was added with an earlier callback time. In this case the
+    ///    original timer is rescheduled when it is the next one to get called.
+    expected_event_id: Cell<TimerEventId>,
+    /// The nesting level of the currently executing timer task or 0.
+    nesting_level: Cell<u32>,
 }
 
+// Holder for the various JS values associated with setTimeout
+// (ie. function value to invoke and all arguments to pass
+//      to the function when calling it)
+// TODO: Handle rooting during fire_timer when movable GC is turned on
 #[derive(JSTraceable, HeapSizeOf)]
 #[privatize]
-pub struct TimerManager {
-    active_timers: DOMRefCell<HashMap<TimerId, TimerHandle>>,
-    next_timer_handle: Cell<i32>,
-}
-
-
-impl Drop for TimerManager {
-    fn drop(&mut self) {
-        for (_, timer_handle) in &mut *self.active_timers.borrow_mut() {
-            timer_handle.cancel();
-        }
-    }
+struct Timer {
+    handle: TimerHandle,
+    source: TimerSource,
+    callback: InternalTimerCallback,
+    is_interval: IsInterval,
+    nesting_level: u32,
+    duration: MsDuration,
+    next_call: MsDuration,
 }
 
 // Enum allowing more descriptive values for the is_interval field
@@ -92,175 +74,269 @@ pub enum IsInterval {
     NonInterval,
 }
 
-// Messages sent control timers from script task
-#[derive(JSTraceable, PartialEq, Copy, Clone, Debug)]
-pub enum TimerControlMsg {
-    Cancel,
-    Suspend,
-    Resume
+impl Ord for Timer {
+    fn cmp(&self, other: &Timer) -> Ordering {
+        match self.next_call.cmp(&other.next_call).reverse() {
+            Ordering::Equal => self.handle.cmp(&other.handle).reverse(),
+            res @ _ => res
+        }
+    }
 }
 
-// Holder for the various JS values associated with setTimeout
-// (ie. function value to invoke and all arguments to pass
-//      to the function when calling it)
-// TODO: Handle rooting during fire_timer when movable GC is turned on
-#[derive(JSTraceable, HeapSizeOf)]
-#[privatize]
-struct TimerData {
-    is_interval: IsInterval,
-    callback: TimerCallback,
-    args: Vec<Heap<JSVal>>
+impl PartialOrd for Timer {
+    fn partial_cmp(&self, other: &Timer) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
 }
 
-impl TimerManager {
-    pub fn new() -> TimerManager {
-        TimerManager {
-            active_timers: DOMRefCell::new(HashMap::new()),
-            next_timer_handle: Cell::new(0)
+impl Eq for Timer {}
+impl PartialEq for Timer {
+    fn eq(&self, other: &Timer) -> bool {
+        self as *const Timer == other as *const Timer
+    }
+}
+
+#[derive(Clone)]
+pub enum TimerCallback {
+    StringTimerCallback(DOMString),
+    FunctionTimerCallback(Rc<Function>),
+}
+
+#[derive(JSTraceable, Clone)]
+enum InternalTimerCallback {
+    StringTimerCallback(DOMString),
+    FunctionTimerCallback(Rc<Function>, Rc<Vec<Heap<JSVal>>>),
+}
+
+impl HeapSizeOf for InternalTimerCallback {
+    fn heap_size_of_children(&self) -> usize {
+        // FIXME: Rc<T> isn't HeapSizeOf and we can't ignore it due to #6870 and #6871
+        0
+    }
+}
+
+impl ActiveTimers {
+    pub fn new(timer_event_chan: Box<TimerEventChan + Send>,
+               scheduler_chan: Sender<TimerEventRequest>)
+               -> ActiveTimers {
+        ActiveTimers {
+            timer_event_chan: timer_event_chan,
+            scheduler_chan: scheduler_chan,
+            next_timer_handle: Cell::new(TimerHandle(1)),
+            timers: DOMRefCell::new(Vec::new()),
+            suspended_since: Cell::new(None),
+            suspension_offset: Cell::new(Length::new(0)),
+            expected_event_id: Cell::new(TimerEventId(0)),
+            nesting_level: Cell::new(0),
+        }
+    }
+
+    // see https://html.spec.whatwg.org/multipage/#timer-initialisation-steps
+    pub fn set_timeout_or_interval(&self,
+                               callback: TimerCallback,
+                               arguments: Vec<HandleValue>,
+                               timeout: i32,
+                               is_interval: IsInterval,
+                               source: TimerSource)
+                               -> i32 {
+        assert!(self.suspended_since.get().is_none());
+
+        // step 3
+        let TimerHandle(new_handle) = self.next_timer_handle.get();
+        self.next_timer_handle.set(TimerHandle(new_handle + 1));
+
+        let timeout = cmp::max(0, timeout);
+        // step 7
+        let duration = self.clamp_duration(Length::new(timeout as u64));
+        let next_call = self.base_time() + duration;
+
+        let callback = match callback {
+            TimerCallback::StringTimerCallback(code_str) =>
+                InternalTimerCallback::StringTimerCallback(code_str),
+            TimerCallback::FunctionTimerCallback(function) => {
+                // This is a bit complicated, but this ensures that the vector's
+                // buffer isn't reallocated (and moved) after setting the Heap values
+                let mut args = Vec::with_capacity(arguments.len());
+                for _ in 0..arguments.len() {
+                    args.push(Heap::default());
+                }
+                for (i, item) in arguments.iter().enumerate() {
+                    args.get_mut(i).unwrap().set(item.get());
+                }
+                InternalTimerCallback::FunctionTimerCallback(function, Rc::new(args))
+            }
+        };
+
+        let timer = Timer {
+            handle: TimerHandle(new_handle),
+            source: source,
+            callback: callback,
+            is_interval: is_interval,
+            duration: duration,
+            // step 6
+            nesting_level: self.nesting_level.get() + 1,
+            next_call: next_call,
+        };
+
+        self.insert_timer(timer);
+
+        let TimerHandle(max_handle) = self.timers.borrow().last().unwrap().handle;
+        if max_handle == new_handle {
+            self.schedule_timer_call();
+        }
+
+        // step 10
+        new_handle
+    }
+
+    pub fn clear_timeout_or_interval(&self, handle: i32) {
+        let handle = TimerHandle(handle);
+        let was_next = self.is_next_timer(handle);
+
+        self.timers.borrow_mut().retain(|t| t.handle != handle);
+
+        if was_next {
+            self.invalidate_expected_event_id();
+            self.schedule_timer_call();
+        }
+    }
+
+    // see https://html.spec.whatwg.org/multipage/#timer-initialisation-steps
+    #[allow(unsafe_code)]
+    pub fn fire_timer<T: Reflectable>(&self, id: TimerEventId, this: &T) {
+        let expected_id = self.expected_event_id.get();
+        if expected_id != id {
+            debug!("ignoring timer fire event {:?} (expected {:?}", id, expected_id);
+            return;
+        }
+
+        assert!(self.suspended_since.get().is_none());
+
+        let base_time = self.base_time();
+
+        // Since the event id was the expected one, at least one timer should be due.
+        assert!(base_time >= self.timers.borrow().last().unwrap().next_call);
+
+        loop {
+            let timer = {
+                let mut timers = self.timers.borrow_mut();
+
+                if timers.is_empty() || timers.last().unwrap().next_call > base_time {
+                    break;
+                }
+
+                timers.pop().unwrap()
+            };
+            let callback = timer.callback.clone();
+
+            // prep for step 6 in nested set_timeout_or_interval calls
+            self.nesting_level.set(timer.nesting_level);
+
+            // step 4.3
+            if timer.is_interval == IsInterval::Interval {
+                let mut timer = timer;
+
+                // step 7
+                timer.duration = self.clamp_duration(timer.duration);
+                // step 8, 9
+                timer.nesting_level += 1;
+                timer.next_call = base_time + timer.duration;
+                self.insert_timer(timer);
+            }
+
+            // step 14
+            match callback {
+                InternalTimerCallback::StringTimerCallback(code_str) => {
+                    let proxy = this.reflector().get_jsobject();
+                    let cx = global_object_for_js_object(proxy.get()).r().get_cx();
+                    let mut rval = RootedValue::new(cx, UndefinedValue());
+
+                    this.evaluate_js_on_global_with_result(&code_str, rval.handle_mut());
+                },
+                InternalTimerCallback::FunctionTimerCallback(function, arguments) => {
+                    let arguments: Vec<JSVal> = arguments.iter().map(|arg| arg.get()).collect();
+                    let arguments = arguments.iter().by_ref().map(|arg| unsafe {
+                        HandleValue::from_marked_location(arg)
+                    }).collect();
+
+                    let _ = function.Call_(this, arguments, Report);
+                }
+            };
+
+            self.nesting_level.set(0);
+        }
+
+        self.schedule_timer_call();
+    }
+
+    fn insert_timer(&self, timer: Timer) {
+        let mut timers = self.timers.borrow_mut();
+        let insertion_index = timers.binary_search(&timer).err().unwrap();
+        timers.insert(insertion_index, timer);
+    }
+
+    fn is_next_timer(&self, handle: TimerHandle) -> bool {
+        match self.timers.borrow().last() {
+            None => false,
+            Some(ref max_timer) => max_timer.handle == handle
+        }
+    }
+
+    fn schedule_timer_call(&self) {
+        assert!(self.suspended_since.get().is_none());
+
+        let timers = self.timers.borrow();
+
+        if let Some(timer) = timers.last() {
+            let expected_event_id = self.invalidate_expected_event_id();
+
+            let delay = Length::new(timer.next_call.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();
         }
     }
 
     pub fn suspend(&self) {
-        for (_, timer_handle) in &mut *self.active_timers.borrow_mut() {
-            timer_handle.suspend();
-        }
+        assert!(self.suspended_since.get().is_none());
+
+        self.suspended_since.set(Some(precise_time_ms()));
+        self.invalidate_expected_event_id();
     }
+
     pub fn resume(&self) {
-        for (_, timer_handle) in &mut *self.active_timers.borrow_mut() {
-            timer_handle.resume();
-        }
-    }
+        assert!(self.suspended_since.get().is_some());
 
-    #[allow(unsafe_code)]
-    pub fn set_timeout_or_interval(&self,
-                                  callback: TimerCallback,
-                                  arguments: Vec<HandleValue>,
-                                  timeout: i32,
-                                  is_interval: IsInterval,
-                                  source: TimerSource,
-                                  script_chan: Box<ScriptChan + Send>)
-                                  -> i32 {
-        let duration_ms = cmp::max(0, timeout) as u32;
-        let handle = self.next_timer_handle.get();
-        self.next_timer_handle.set(handle + 1);
-
-        // Spawn a new timer task; it will dispatch the `CommonScriptMsg::FireTimer`
-        // to the relevant script handler that will deal with it.
-        let (control_chan, control_port) = channel();
-        let spawn_name = match source {
-            TimerSource::FromWindow(_) if is_interval == IsInterval::Interval => "Window:SetInterval",
-            TimerSource::FromWorker if is_interval == IsInterval::Interval => "Worker:SetInterval",
-            TimerSource::FromWindow(_) => "Window:SetTimeout",
-            TimerSource::FromWorker => "Worker:SetTimeout",
-        }.to_owned();
-        spawn_named(spawn_name, move || {
-            let timeout_port = if is_interval == IsInterval::Interval {
-                horribly_inefficient_timers::periodic(duration_ms)
-            } else {
-                horribly_inefficient_timers::oneshot(duration_ms)
-            };
-            let control_port = control_port;
-
-            let select = Select::new();
-            let mut timeout_handle = select.handle(&timeout_port);
-            unsafe { timeout_handle.add() };
-            let mut control_handle = select.handle(&control_port);
-            unsafe { control_handle.add() };
-
-            loop {
-                let id = select.wait();
-
-                if id == timeout_handle.id() {
-                    timeout_port.recv().unwrap();
-                    if script_chan.send(CommonScriptMsg::FireTimer(source, TimerId(handle))).is_err() {
-                        break;
-                    }
-
-                    if is_interval == IsInterval::NonInterval {
-                        break;
-                    }
-                } else if id == control_handle.id() {
-                    match control_port.recv().unwrap() {
-                        TimerControlMsg::Suspend => {
-                            let msg = control_port.recv().unwrap();
-                            match msg {
-                                TimerControlMsg::Suspend => panic!("Nothing to suspend!"),
-                                TimerControlMsg::Resume => {},
-                                TimerControlMsg::Cancel => {
-                                    break;
-                                },
-                            }
-                        },
-                        TimerControlMsg::Resume => panic!("Nothing to resume!"),
-                        TimerControlMsg::Cancel => {
-                            break;
-                        }
-                    }
-                }
-            }
-        });
-        let timer_id = TimerId(handle);
-        let timer = TimerHandle {
-            handle: timer_id,
-            control_chan: Some(control_chan),
-            data: TimerData {
-                is_interval: is_interval,
-                callback: callback,
-                args: Vec::with_capacity(arguments.len())
-            }
+        let additional_offset = match self.suspended_since.get() {
+            Some(suspended_since) => precise_time_ms() - suspended_since,
+            None => panic!("Timers are not suspended.")
         };
-        self.active_timers.borrow_mut().insert(timer_id, timer);
 
-        // This is a bit complicated, but this ensures that the vector's
-        // buffer isn't reallocated (and moved) after setting the Heap values
-        let mut timers = self.active_timers.borrow_mut();
-        let mut timer = timers.get_mut(&timer_id).unwrap();
-        for _ in 0..arguments.len() {
-            timer.data.args.push(Heap::default());
-        }
-        for (i, item) in arguments.iter().enumerate() {
-            timer.data.args.get_mut(i).unwrap().set(item.get());
-        }
-        handle
+        self.suspension_offset.set(self.suspension_offset.get() + additional_offset);
+
+        self.schedule_timer_call();
     }
 
-    pub fn clear_timeout_or_interval(&self, handle: i32) {
-        let mut timer_handle = self.active_timers.borrow_mut().remove(&TimerId(handle));
-        match timer_handle {
-            Some(ref mut handle) => handle.cancel(),
-            None => {}
-        }
+    fn base_time(&self) -> MsDuration {
+        precise_time_ms() - self.suspension_offset.get()
     }
 
-    #[allow(unsafe_code)]
-    pub fn fire_timer<T: Reflectable>(&self, timer_id: TimerId, this: &T) {
+    // see step 7 of https://html.spec.whatwg.org/multipage/#timer-initialisation-steps
+    fn clamp_duration(&self, unclamped: MsDuration) -> MsDuration {
+        let ms = if self.nesting_level.get() > 5 {
+            4
+        } else {
+            0
+        };
 
-        let (is_interval, callback, args): (IsInterval, TimerCallback, Vec<JSVal>) =
-            match self.active_timers.borrow().get(&timer_id) {
-                Some(timer_handle) =>
-                    (timer_handle.data.is_interval,
-                     timer_handle.data.callback.clone(),
-                     timer_handle.data.args.iter().map(|arg| arg.get()).collect()),
-                None => return,
-            };
+        cmp::max(Length::new(ms), unclamped)
+    }
 
-        match callback {
-            TimerCallback::FunctionTimerCallback(function) => {
-                let arg_handles = args.iter().by_ref().map(|arg| unsafe {
-                    HandleValue::from_marked_location(arg)
-                }).collect();
-                let _ = function.Call_(this, arg_handles, Report);
-            }
-            TimerCallback::StringTimerCallback(code_str) => {
-                let proxy = this.reflector().get_jsobject();
-                let cx = global_object_for_js_object(proxy.get()).r().get_cx();
-                let mut rval = RootedValue::new(cx, UndefinedValue());
-                this.evaluate_js_on_global_with_result(&code_str, rval.handle_mut());
-            }
-        }
-
-        if is_interval == IsInterval::NonInterval {
-            self.active_timers.borrow_mut().remove(&timer_id);
-        }
+    fn invalidate_expected_event_id(&self) -> TimerEventId {
+        let TimerEventId(currently_expected) = self.expected_event_id.get();
+        let next_id = TimerEventId(currently_expected + 1);
+        debug!("invalidating expected timer (was {:?}, now {:?}", currently_expected, next_id);
+        self.expected_event_id.set(next_id);
+        next_id
     }
 }

servo/components/script_traits/Cargo.toml

@@ -38,3 +38,4 @@ libc = "0.1"
 euclid = "0.2"
 serde = "0.6"
 serde_macros = "0.5"
+time = "0.1.12"

servo/components/script_traits/lib.rs

@@ -19,11 +19,13 @@ extern crate msg;
 extern crate net_traits;
 extern crate profile_traits;
 extern crate serde;
+extern crate time;
 extern crate url;
 extern crate util;
 
 use app_units::Au;
 use devtools_traits::ScriptToDevtoolsControlMsg;
+use euclid::length::Length;
 use euclid::point::Point2D;
 use euclid::rect::Rect;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
@@ -36,10 +38,11 @@ use msg::webdriver_msg::WebDriverScriptCommand;
 use net_traits::ResourceTask;
 use net_traits::image_cache_task::ImageCacheTask;
 use net_traits::storage_task::StorageTask;
-use profile_traits::{mem, time};
+use profile_traits::mem;
 use std::any::Any;
 use std::sync::mpsc::{Receiver, Sender};
 use url::Url;
+use util::mem::HeapSizeOf;
 
 /// The address of a node. Layout sends these back. They must be validated via
 /// `from_untrusted_node_address` before they can be used, because we do not trust layout.
@@ -177,6 +180,56 @@ pub enum CompositorEvent {
 /// crates that don't need to know about them.
 pub struct OpaqueScriptLayoutChannel(pub (Box<Any + Send>, Box<Any + Send>));
 
+/// Requests a TimerEvent-Message be sent after the given duration.
+pub struct TimerEventRequest(pub Box<TimerEventChan + Send>, pub TimerSource, pub TimerEventId, pub MsDuration);
+
+/// Notifies the script task to fire due timers.
+/// TimerSource must be FromWindow when dispatched to ScriptTask and
+/// must be FromWorker when dispatched to a DedicatedGlobalWorkerScope
+pub struct TimerEvent(pub TimerSource, pub TimerEventId);
+
+/// A cloneable interface for sending timer events.
+pub trait TimerEventChan {
+    /// Send a timer event to the associated event loop.
+    fn send(&self, msg: TimerEvent) -> Result<(), ()>;
+    /// Clone this handle.
+    fn clone(&self) -> Box<TimerEventChan + Send>;
+}
+
+/// Describes the task that requested the TimerEvent.
+#[derive(Copy, Clone, HeapSizeOf)]
+pub enum TimerSource {
+    /// The event was requested from a window (ScriptTask).
+    FromWindow(PipelineId),
+    /// The event was requested from a worker (DedicatedGlobalWorkerScope).
+    FromWorker
+}
+
+/// The id to be used for a TimerEvent is defined by the corresponding TimerEventRequest.
+#[derive(PartialEq, Eq, Copy, Clone, Debug, HeapSizeOf)]
+pub struct TimerEventId(pub u32);
+
+/// Unit of measurement.
+#[derive(Clone, Copy, HeapSizeOf)]
+pub enum Milliseconds {}
+/// Unit of measurement.
+#[derive(Clone, Copy, HeapSizeOf)]
+pub enum Nanoseconds {}
+
+/// Amount of milliseconds.
+pub type MsDuration = Length<Milliseconds, u64>;
+/// Amount of nanoseconds.
+pub type NsDuration = Length<Nanoseconds, u64>;
+
+/// Returns the duration since an unspecified epoch measured in ms.
+pub fn precise_time_ms() -> MsDuration {
+    Length::new(time::precise_time_ns() / (1000 * 1000))
+}
+/// Returns the duration since an unspecified epoch measured in ns.
+pub fn precise_time_ns() -> NsDuration {
+    Length::new(time::precise_time_ns())
+}
+
 /// Data needed to construct a script thread.
 pub struct InitialScriptState {
     /// The ID of the pipeline with which this script thread is associated.
@@ -192,6 +245,8 @@ pub struct InitialScriptState {
     pub control_port: Receiver<ConstellationControlMsg>,
     /// A channel on which messages can be sent to the constellation from script.
     pub constellation_chan: ConstellationChan,
+    /// A channel to schedule timer events.
+    pub scheduler_chan: Sender<TimerEventRequest>,
     /// Information that script sends out when it panics.
     pub failure_info: Failure,
     /// A channel to the resource manager task.
@@ -201,7 +256,7 @@ pub struct InitialScriptState {
     /// A channel to the image cache task.
     pub image_cache_task: ImageCacheTask,
     /// A channel to the time profiler thread.
-    pub time_profiler_chan: time::ProfilerChan,
+    pub time_profiler_chan: profile_traits::time::ProfilerChan,
     /// A channel to the memory profiler thread.
     pub mem_profiler_chan: mem::ProfilerChan,
     /// A channel to the developer tools, if applicable.

servo/components/servo/Cargo.lock

@@ -1567,6 +1567,7 @@ dependencies = [
  "profile_traits 0.0.1",
  "serde 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_macros 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "time 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.37 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
 ]

servo/ports/cef/Cargo.lock

@@ -1491,6 +1491,7 @@ dependencies = [
  "profile_traits 0.0.1",
  "serde 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_macros 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "time 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.37 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
 ]

servo/ports/gonk/Cargo.lock

@@ -1353,6 +1353,7 @@ dependencies = [
  "profile_traits 0.0.1",
  "serde 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_macros 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "time 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 0.2.37 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
 ]