1 files changed, 151 insertions, 0 deletions
diff --git a/xpcom/threads/SchedulerGroup.cpp b/xpcom/threads/SchedulerGroup.cpp
new file mode 100644
index 0000000000..376bd22627
--- /dev/null
+++ b/xpcom/threads/SchedulerGroup.cpp
@@ -0,0 +1,151 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#include "mozilla/SchedulerGroup.h"
+
+#include <utility>
+
+#include "jsfriendapi.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/Unused.h"
+#include "mozilla/dom/DocGroup.h"
+#include "mozilla/dom/ScriptSettings.h"
+#include "nsINamed.h"
+#include "nsQueryObject.h"
+#include "nsThreadUtils.h"
+
+using namespace mozilla;
+
+namespace {
+
+static Atomic<uint64_t> gEarliestUnprocessedVsync(0);
+
+}  // namespace
+
+/* static */
+nsresult SchedulerGroup::UnlabeledDispatch(
+    TaskCategory aCategory, already_AddRefed<nsIRunnable>&& aRunnable) {
+  if (NS_IsMainThread()) {
+    return NS_DispatchToCurrentThread(std::move(aRunnable));
+  } else {
+    return NS_DispatchToMainThread(std::move(aRunnable));
+  }
+}
+
+/* static */
+void SchedulerGroup::MarkVsyncReceived() {
+  // May be called on any thread when a vsync is received and scheduled to be
+  // processed. This may occur on the main thread due to queued messages when
+  // the channel is connected.
+  TimeStamp creation = TimeStamp::ProcessCreation();
+
+  // Attempt to set gEarliestUnprocessedVsync to our new value. If we've seen a
+  // vsync already, but haven't handled it, the `compareExchange` will fail and
+  // the static won't be updated.
+  uint64_t unprocessedVsync =
+      uint64_t((TimeStamp::Now() - creation).ToMicroseconds());
+  gEarliestUnprocessedVsync.compareExchange(0, unprocessedVsync);
+}
+
+/* static */
+void SchedulerGroup::MarkVsyncRan() { gEarliestUnprocessedVsync = 0; }
+
+SchedulerGroup::SchedulerGroup() : mIsRunning(false) {}
+
+/* static */
+nsresult SchedulerGroup::Dispatch(TaskCategory aCategory,
+                                  already_AddRefed<nsIRunnable>&& aRunnable) {
+  return LabeledDispatch(aCategory, std::move(aRunnable), nullptr);
+}
+
+/* static */
+nsresult SchedulerGroup::LabeledDispatch(
+    TaskCategory aCategory, already_AddRefed<nsIRunnable>&& aRunnable,
+    mozilla::PerformanceCounter* aPerformanceCounter) {
+  nsCOMPtr<nsIRunnable> runnable(aRunnable);
+  if (XRE_IsContentProcess()) {
+    RefPtr<Runnable> internalRunnable =
+        new Runnable(runnable.forget(), aPerformanceCounter);
+    return InternalUnlabeledDispatch(aCategory, internalRunnable.forget());
+  }
+  return UnlabeledDispatch(aCategory, runnable.forget());
+}
+
+/*static*/
+nsresult SchedulerGroup::InternalUnlabeledDispatch(
+    TaskCategory aCategory, already_AddRefed<Runnable>&& aRunnable) {
+  if (NS_IsMainThread()) {
+    // NS_DispatchToCurrentThread will not leak the passed in runnable
+    // when it fails, so we don't need to do anything special.
+    return NS_DispatchToCurrentThread(std::move(aRunnable));
+  }
+
+  RefPtr<Runnable> runnable(aRunnable);
+  nsresult rv = NS_DispatchToMainThread(do_AddRef(runnable));
+  if (NS_FAILED(rv)) {
+    // Dispatch failed.  This is a situation where we would have used
+    // NS_DispatchToMainThread rather than calling into the SchedulerGroup
+    // machinery, and the caller would be expecting to leak the nsIRunnable
+    // originally passed in.  But because we've had to wrap things up
+    // internally, we were going to leak the nsIRunnable *and* our Runnable
+    // wrapper.  But there's no reason that we have to leak our Runnable
+    // wrapper; we can just leak the wrapped nsIRunnable, and let the caller
+    // take care of unleaking it if they need to.
+    Unused << runnable->mRunnable.forget().take();
+    nsrefcnt refcnt = runnable.get()->Release();
+    MOZ_RELEASE_ASSERT(refcnt == 1, "still holding an unexpected reference!");
+  }
+
+  return rv;
+}
+
+SchedulerGroup::Runnable::Runnable(
+    already_AddRefed<nsIRunnable>&& aRunnable,
+    mozilla::PerformanceCounter* aPerformanceCounter)
+    : mozilla::Runnable("SchedulerGroup::Runnable"),
+      mRunnable(std::move(aRunnable)),
+      mPerformanceCounter(aPerformanceCounter) {}
+
+mozilla::PerformanceCounter* SchedulerGroup::Runnable::GetPerformanceCounter()
+    const {
+  return mPerformanceCounter;
+}
+
+#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
+NS_IMETHODIMP
+SchedulerGroup::Runnable::GetName(nsACString& aName) {
+  // Try to get a name from the underlying runnable.
+  nsCOMPtr<nsINamed> named = do_QueryInterface(mRunnable);
+  if (named) {
+    named->GetName(aName);
+  }
+  if (aName.IsEmpty()) {
+    aName.AssignLiteral("anonymous");
+  }
+
+  return NS_OK;
+}
+#endif
+
+NS_IMETHODIMP
+SchedulerGroup::Runnable::Run() {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+  // The runnable's destructor can have side effects, so try to execute it in
+  // the scope of the SchedulerGroup.
+  nsCOMPtr<nsIRunnable> runnable(std::move(mRunnable));
+  return runnable->Run();
+}
+
+NS_IMETHODIMP
+SchedulerGroup::Runnable::GetPriority(uint32_t* aPriority) {
+  *aPriority = nsIRunnablePriority::PRIORITY_NORMAL;
+  nsCOMPtr<nsIRunnablePriority> runnablePrio = do_QueryInterface(mRunnable);
+  return runnablePrio ? runnablePrio->GetPriority(aPriority) : NS_OK;
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(SchedulerGroup::Runnable, mozilla::Runnable,
+                            nsIRunnablePriority, SchedulerGroup::Runnable)