1 files changed, 61 insertions, 0 deletions
diff --git a/components/script/task_source/performance_timeline.rs b/components/script/task_source/performance_timeline.rs
new file mode 100644
index 00000000000..1669ac6e689
--- /dev/null
+++ b/components/script/task_source/performance_timeline.rs
@@ -0,0 +1,61 @@
+/* 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 https://mozilla.org/MPL/2.0/. */
+
+// XXX The spec says that the performance timeline task source should be
+//     a low priority task and it should be processed during idle periods.
+//     We are currently treating this task queue as a normal priority queue.
+
+use crate::dom::bindings::refcounted::Trusted;
+use crate::dom::globalscope::GlobalScope;
+use crate::script_runtime::{CommonScriptMsg, ScriptChan, ScriptThreadEventCategory};
+use crate::task::{TaskCanceller, TaskOnce};
+use crate::task_source::{TaskSource, TaskSourceName};
+use msg::constellation_msg::PipelineId;
+use std::fmt;
+use std::result::Result;
+
+#[derive(JSTraceable)]
+pub struct PerformanceTimelineTaskSource(pub Box<dyn ScriptChan + Send + 'static>, pub PipelineId);
+
+impl Clone for PerformanceTimelineTaskSource {
+    fn clone(&self) -> PerformanceTimelineTaskSource {
+        PerformanceTimelineTaskSource(self.0.clone(), self.1.clone())
+    }
+}
+
+impl fmt::Debug for PerformanceTimelineTaskSource {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "PerformanceTimelineTaskSource(...)")
+    }
+}
+
+impl TaskSource for PerformanceTimelineTaskSource {
+    const NAME: TaskSourceName = TaskSourceName::PerformanceTimeline;
+
+    fn queue_with_canceller<T>(&self, task: T, canceller: &TaskCanceller) -> Result<(), ()>
+    where
+        T: TaskOnce + 'static,
+    {
+        let msg = CommonScriptMsg::Task(
+            ScriptThreadEventCategory::PerformanceTimelineTask,
+            Box::new(canceller.wrap_task(task)),
+            Some(self.1),
+            PerformanceTimelineTaskSource::NAME,
+        );
+        self.0.send(msg).map_err(|_| ())
+    }
+}
+
+impl PerformanceTimelineTaskSource {
+    pub fn queue_notification(&self, global: &GlobalScope) {
+        let owner = Trusted::new(&*global.performance());
+        // FIXME(nox): Why are errors silenced here?
+        let _ = self.queue(
+            task!(notify_performance_observers: move || {
+                owner.root().notify_observers();
+            }),
+            global,
+        );
+    }
+}