Expose DOMHighResTimeStamps at lower res

components/script/dom/event.rs

@@ -10,7 +10,6 @@ use crate::dom::bindings::codegen::Bindings::PerformanceBinding::DOMHighResTimeS
 use crate::dom::bindings::codegen::Bindings::PerformanceBinding::PerformanceBinding::PerformanceMethods;
 use crate::dom::bindings::error::Fallible;
 use crate::dom::bindings::inheritance::Castable;
-use crate::dom::bindings::num::Finite;
 use crate::dom::bindings::refcounted::Trusted;
 use crate::dom::bindings::reflector::{reflect_dom_object, DomObject, Reflector};
 use crate::dom::bindings::root::{DomRoot, DomSlice, MutNullableDom};
@@ -19,6 +18,7 @@ use crate::dom::document::Document;
 use crate::dom::eventtarget::{CompiledEventListener, EventTarget, ListenerPhase};
 use crate::dom::globalscope::GlobalScope;
 use crate::dom::node::Node;
+use crate::dom::performance::reduce_timing_resolution;
 use crate::dom::virtualmethods::vtable_for;
 use crate::dom::window::Window;
 use crate::task::TaskOnce;
@@ -333,7 +333,7 @@ impl EventMethods for Event {
 
     // https://dom.spec.whatwg.org/#dom-event-timestamp
     fn TimeStamp(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(
+        reduce_timing_resolution(
             (self.precise_time_ns - (*self.global().performance().TimeOrigin()).round() as u64)
                 .to_ms(),
         )

components/script/dom/performance.rs

@@ -401,12 +401,12 @@ impl PerformanceMethods for Performance {
 
     // https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/HighResolutionTime/Overview.html#dom-performance-now
     fn Now(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.now())
+        reduce_timing_resolution(self.now())
     }
 
     // https://www.w3.org/TR/hr-time-2/#dom-performance-timeorigin
     fn TimeOrigin(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.navigation_start_precise as f64)
+        reduce_timing_resolution(self.navigation_start_precise as f64)
     }
 
     // https://www.w3.org/TR/performance-timeline-2/#dom-performance-getentries
@@ -525,3 +525,14 @@ impl PerformanceMethods for Performance {
         SetOnresourcetimingbufferfull
     );
 }
+
+// https://www.w3.org/TR/hr-time-2/#clock-resolution
+pub fn reduce_timing_resolution(exact: f64) -> DOMHighResTimeStamp {
+    // We need a granularity no finer than 5 microseconds.
+    // 5 microseconds isn't an exactly representable f64 so WPT tests
+    // might occasionally corner-case on rounding.
+    // web-platform-tests/wpt#21526 wants us to use an integer number of
+    // microseconds; the next divisor of milliseconds up from 5 microseconds
+    // is 10, which is 1/100th of a millisecond.
+    Finite::wrap((exact * 100.0).floor() / 100.0)
+}

components/script/dom/performanceentry.rs

@@ -2,13 +2,14 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use crate::dom::bindings::codegen::Bindings::PerformanceBinding::DOMHighResTimeStamp;
 use crate::dom::bindings::codegen::Bindings::PerformanceEntryBinding;
 use crate::dom::bindings::codegen::Bindings::PerformanceEntryBinding::PerformanceEntryMethods;
-use crate::dom::bindings::num::Finite;
 use crate::dom::bindings::reflector::{reflect_dom_object, Reflector};
 use crate::dom::bindings::root::DomRoot;
 use crate::dom::bindings::str::DOMString;
 use crate::dom::globalscope::GlobalScope;
+use crate::dom::performance::reduce_timing_resolution;
 use dom_struct::dom_struct;
 
 #[dom_struct]
@@ -77,12 +78,12 @@ impl PerformanceEntryMethods for PerformanceEntry {
     }
 
     // https://w3c.github.io/performance-timeline/#dom-performanceentry-starttime
-    fn StartTime(&self) -> Finite<f64> {
-        Finite::wrap(self.start_time)
+    fn StartTime(&self) -> DOMHighResTimeStamp {
+        reduce_timing_resolution(self.start_time)
     }
 
     // https://w3c.github.io/performance-timeline/#dom-performanceentry-duration
-    fn Duration(&self) -> Finite<f64> {
-        Finite::wrap(self.duration)
+    fn Duration(&self) -> DOMHighResTimeStamp {
+        reduce_timing_resolution(self.duration)
     }
 }

components/script/dom/performanceresourcetiming.rs

@@ -6,11 +6,11 @@ use crate::dom::bindings::codegen::Bindings::PerformanceBinding::DOMHighResTimeS
 use crate::dom::bindings::codegen::Bindings::PerformanceResourceTimingBinding::{
     self, PerformanceResourceTimingMethods,
 };
-use crate::dom::bindings::num::Finite;
 use crate::dom::bindings::reflector::reflect_dom_object;
 use crate::dom::bindings::root::DomRoot;
 use crate::dom::bindings::str::DOMString;
 use crate::dom::globalscope::GlobalScope;
+use crate::dom::performance::reduce_timing_resolution;
 use crate::dom::performanceentry::PerformanceEntry;
 use dom_struct::dom_struct;
 use net_traits::ResourceFetchTiming;
@@ -182,17 +182,17 @@ impl PerformanceResourceTimingMethods for PerformanceResourceTiming {
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-domainlookupstart
     fn DomainLookupStart(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.domain_lookup_start)
+        reduce_timing_resolution(self.domain_lookup_start)
     }
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-domainlookupend
     fn DomainLookupEnd(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.domain_lookup_end)
+        reduce_timing_resolution(self.domain_lookup_end)
     }
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-secureconnectionstart
     fn SecureConnectionStart(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.secure_connection_start)
+        reduce_timing_resolution(self.secure_connection_start)
     }
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-transfersize
@@ -212,41 +212,41 @@ impl PerformanceResourceTimingMethods for PerformanceResourceTiming {
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-requeststart
     fn RequestStart(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.request_start)
+        reduce_timing_resolution(self.request_start)
     }
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-redirectstart
     fn RedirectStart(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.redirect_start)
+        reduce_timing_resolution(self.redirect_start)
     }
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-redirectend
     fn RedirectEnd(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.redirect_end)
+        reduce_timing_resolution(self.redirect_end)
     }
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-responsestart
     fn ResponseStart(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.response_start)
+        reduce_timing_resolution(self.response_start)
     }
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-fetchstart
     fn FetchStart(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.fetch_start)
+        reduce_timing_resolution(self.fetch_start)
     }
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-connectstart
     fn ConnectStart(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.connect_start)
+        reduce_timing_resolution(self.connect_start)
     }
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-connectend
     fn ConnectEnd(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.connect_end)
+        reduce_timing_resolution(self.connect_end)
     }
 
     // https://w3c.github.io/resource-timing/#dom-performanceresourcetiming-responseend
     fn ResponseEnd(&self) -> DOMHighResTimeStamp {
-        Finite::wrap(self.response_end)
+        reduce_timing_resolution(self.response_end)
     }
 }

components/script/dom/vrframedata.rs

@@ -2,13 +2,14 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use crate::dom::bindings::codegen::Bindings::PerformanceBinding::DOMHighResTimeStamp;
 use crate::dom::bindings::codegen::Bindings::VRFrameDataBinding;
 use crate::dom::bindings::codegen::Bindings::VRFrameDataBinding::VRFrameDataMethods;
 use crate::dom::bindings::error::Fallible;
-use crate::dom::bindings::num::Finite;
 use crate::dom::bindings::reflector::{reflect_dom_object, DomObject, Reflector};
 use crate::dom::bindings::root::{Dom, DomRoot};
 use crate::dom::globalscope::GlobalScope;
+use crate::dom::performance::reduce_timing_resolution;
 use crate::dom::vrpose::VRPose;
 use crate::dom::window::Window;
 use crate::script_runtime::JSContext;
@@ -119,8 +120,8 @@ impl VRFrameData {
 
 impl VRFrameDataMethods for VRFrameData {
     // https://w3c.github.io/webvr/#dom-vrframedata-timestamp
-    fn Timestamp(&self) -> Finite<f64> {
-        Finite::wrap(self.timestamp.get() - self.first_timestamp.get())
+    fn Timestamp(&self) -> DOMHighResTimeStamp {
+        reduce_timing_resolution(self.timestamp.get() - self.first_timestamp.get())
     }
 
     #[allow(unsafe_code)]

components/script/dom/xrsession.rs

@@ -19,7 +19,6 @@ use crate::dom::bindings::codegen::Bindings::XRSessionBinding::XRVisibilityState
 use crate::dom::bindings::codegen::Bindings::XRWebGLLayerBinding::XRWebGLLayerMethods;
 use crate::dom::bindings::error::{Error, ErrorResult};
 use crate::dom::bindings::inheritance::Castable;
-use crate::dom::bindings::num::Finite;
 use crate::dom::bindings::refcounted::Trusted;
 use crate::dom::bindings::reflector::{reflect_dom_object, DomObject};
 use crate::dom::bindings::root::{Dom, DomRoot, MutDom, MutNullableDom};
@@ -28,6 +27,7 @@ use crate::dom::eventtarget::EventTarget;
 use crate::dom::globalscope::GlobalScope;
 use crate::dom::node::Node;
 use crate::dom::node::NodeDamage;
+use crate::dom::performance::reduce_timing_resolution;
 use crate::dom::promise::Promise;
 use crate::dom::xrframe::XRFrame;
 use crate::dom::xrinputsourcearray::XRInputSourceArray;
@@ -336,7 +336,7 @@ impl XRSession {
         // Step 4-5
         let mut callbacks = mem::replace(&mut *self.raf_callback_list.borrow_mut(), vec![]);
         let start = self.global().as_window().get_navigation_start();
-        let time = (frame.time_ns - start).to_ms();
+        let time = reduce_timing_resolution((frame.time_ns - start).to_ms());
 
         let frame = XRFrame::new(&self.global(), self, frame);
         // Step 6,7
@@ -347,7 +347,7 @@ impl XRSession {
         self.outside_raf.set(false);
         for (_, callback) in callbacks.drain(..) {
             if let Some(callback) = callback {
-                let _ = callback.Call__(Finite::wrap(time), &frame, ExceptionHandling::Report);
+                let _ = callback.Call__(time, &frame, ExceptionHandling::Report);
             }
         }
         self.outside_raf.set(true);

tests/wpt/mozilla/meta/MANIFEST.json

@@ -19708,7 +19708,7 @@
    "testharness"
   ],
   "mozilla/window_performance.html": [
-   "302073e8041763102d678326509d7ef0a1fb5c79",
+   "c1e38a1e00147caf82492dc82f1cb5e85759f8e3",
    "testharness"
   ],
   "mozilla/window_performance_topLevelDomComplete.html": [

tests/wpt/mozilla/tests/mozilla/window_performance.html

@@ -27,12 +27,15 @@
   var last = window.performance.now();
   assert_greater_than(last, 0);
 
-  // Check that window.performance.now() is monotonically increasing
+  // Check that window.performance.now() is monotonically nondecreasing
+  // and eventually increases
+  var before_loop = window.performance.now();
   for (var i = 0; i < 100; i++) {
     var next = window.performance.now();
-    assert_greater_than(next, last);
+    assert_greater_than_equal(next, last);
     last = next;
   }
+  assert_greater_than(last, before_loop, "If this fails, either performance timing is broken, or Servo JS execution has gotten much faster since this test was written.");
 });
 </script>
 </body>