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-rw-r--r--xpcom/threads/IdleTaskRunner.cpp280
1 files changed, 280 insertions, 0 deletions
diff --git a/xpcom/threads/IdleTaskRunner.cpp b/xpcom/threads/IdleTaskRunner.cpp
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+++ b/xpcom/threads/IdleTaskRunner.cpp
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+/* -*- 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 "IdleTaskRunner.h"
+#include "mozilla/TaskCategory.h"
+#include "mozilla/TaskController.h"
+#include "nsRefreshDriver.h"
+
+namespace mozilla {
+
+already_AddRefed<IdleTaskRunner> IdleTaskRunner::Create(
+ const CallbackType& aCallback, const char* aRunnableName,
+ TimeDuration aStartDelay, TimeDuration aMaxDelay,
+ TimeDuration aMinimumUsefulBudget, bool aRepeating,
+ const MayStopProcessingCallbackType& aMayStopProcessing,
+ const RequestInterruptCallbackType& aRequestInterrupt) {
+ if (aMayStopProcessing && aMayStopProcessing()) {
+ return nullptr;
+ }
+
+ RefPtr<IdleTaskRunner> runner = new IdleTaskRunner(
+ aCallback, aRunnableName, aStartDelay, aMaxDelay, aMinimumUsefulBudget,
+ aRepeating, aMayStopProcessing, aRequestInterrupt);
+ runner->Schedule(false); // Initial scheduling shouldn't use idle dispatch.
+ return runner.forget();
+}
+
+class IdleTaskRunnerTask : public Task {
+ public:
+ explicit IdleTaskRunnerTask(IdleTaskRunner* aRunner)
+ : Task(true, EventQueuePriority::Idle),
+ mRunner(aRunner),
+ mRequestInterrupt(aRunner->mRequestInterrupt) {
+ SetManager(TaskController::Get()->GetIdleTaskManager());
+ }
+
+ bool Run() override {
+ if (mRunner) {
+ // IdleTaskRunner::Run can actually trigger the destruction of the
+ // IdleTaskRunner. Make sure it doesn't get destroyed before the method
+ // finished.
+ RefPtr<IdleTaskRunner> runner(mRunner);
+ runner->Run();
+ }
+ return true;
+ }
+
+ void SetIdleDeadline(TimeStamp aDeadline) override {
+ if (mRunner) {
+ mRunner->SetIdleDeadline(aDeadline);
+ }
+ }
+
+ void Cancel() { mRunner = nullptr; }
+
+ bool GetName(nsACString& aName) override {
+ if (mRunner) {
+ aName.Assign(mRunner->GetName());
+ } else {
+ aName.Assign("ExpiredIdleTaskRunner");
+ }
+ return true;
+ }
+
+ void RequestInterrupt(uint32_t aInterruptPriority) override {
+ if (mRequestInterrupt) {
+ mRequestInterrupt(aInterruptPriority);
+ }
+ }
+
+ private:
+ IdleTaskRunner* mRunner;
+
+ // Copied here and invoked even if there is no mRunner currently, to avoid
+ // race conditions checking mRunner when an interrupt is requested.
+ IdleTaskRunner::RequestInterruptCallbackType mRequestInterrupt;
+};
+
+IdleTaskRunner::IdleTaskRunner(
+ const CallbackType& aCallback, const char* aRunnableName,
+ TimeDuration aStartDelay, TimeDuration aMaxDelay,
+ TimeDuration aMinimumUsefulBudget, bool aRepeating,
+ const MayStopProcessingCallbackType& aMayStopProcessing,
+ const RequestInterruptCallbackType& aRequestInterrupt)
+ : mCallback(aCallback),
+ mStartTime(TimeStamp::Now() + aStartDelay),
+ mMaxDelay(aMaxDelay),
+ mMinimumUsefulBudget(aMinimumUsefulBudget),
+ mRepeating(aRepeating),
+ mTimerActive(false),
+ mMayStopProcessing(aMayStopProcessing),
+ mRequestInterrupt(aRequestInterrupt),
+ mName(aRunnableName) {}
+
+void IdleTaskRunner::Run() {
+ if (!mCallback) {
+ return;
+ }
+
+ // Deadline is null when called from timer or RunNextCollectorTimer rather
+ // than during idle time.
+ TimeStamp now = TimeStamp::Now();
+
+ // Note that if called from RunNextCollectorTimer, we may not have reached
+ // mStartTime yet. Pretend we are overdue for idle time.
+ bool overdueForIdle = mDeadline.IsNull();
+ bool didRun = false;
+ bool allowIdleDispatch = false;
+
+ if (mTask) {
+ // If we find ourselves here we should usually be running from this task,
+ // but there are exceptions. In any case we're doing the work now and don't
+ // need our task going forward unless we're re-scheduled.
+ nsRefreshDriver::CancelIdleTask(mTask);
+ // Extra safety, make sure a task can never have a dangling ptr.
+ mTask->Cancel();
+ mTask = nullptr;
+ }
+
+ if (overdueForIdle || ((now + mMinimumUsefulBudget) < mDeadline)) {
+ CancelTimer();
+ didRun = mCallback(mDeadline);
+ // If we didn't do meaningful work, don't schedule using immediate
+ // idle dispatch, since that could lead to a loop until the idle
+ // period ends.
+ allowIdleDispatch = didRun;
+ } else if (now >= mDeadline) {
+ allowIdleDispatch = true;
+ }
+
+ if (mCallback && (mRepeating || !didRun)) {
+ Schedule(allowIdleDispatch);
+ } else {
+ mCallback = nullptr;
+ }
+}
+
+static void TimedOut(nsITimer* aTimer, void* aClosure) {
+ RefPtr<IdleTaskRunner> runner = static_cast<IdleTaskRunner*>(aClosure);
+ runner->Run();
+}
+
+void IdleTaskRunner::SetIdleDeadline(mozilla::TimeStamp aDeadline) {
+ mDeadline = aDeadline;
+}
+
+void IdleTaskRunner::SetMinimumUsefulBudget(int64_t aMinimumUsefulBudget) {
+ mMinimumUsefulBudget = TimeDuration::FromMilliseconds(aMinimumUsefulBudget);
+}
+
+void IdleTaskRunner::SetTimer(TimeDuration aDelay, nsIEventTarget* aTarget) {
+ MOZ_ASSERT(NS_IsMainThread());
+ MOZ_ASSERT(aTarget->IsOnCurrentThread());
+ // aTarget is always the main thread event target provided from
+ // NS_DispatchToCurrentThreadQueue(). We ignore aTarget here to ensure that
+ // CollectorRunner always run specifically the main thread.
+ SetTimerInternal(aDelay);
+}
+
+void IdleTaskRunner::Cancel() {
+ CancelTimer();
+ mTimer = nullptr;
+ mScheduleTimer = nullptr;
+ mCallback = nullptr;
+}
+
+static void ScheduleTimedOut(nsITimer* aTimer, void* aClosure) {
+ RefPtr<IdleTaskRunner> runnable = static_cast<IdleTaskRunner*>(aClosure);
+ runnable->Schedule(true);
+}
+
+void IdleTaskRunner::Schedule(bool aAllowIdleDispatch) {
+ if (!mCallback) {
+ return;
+ }
+
+ if (mMayStopProcessing && mMayStopProcessing()) {
+ Cancel();
+ return;
+ }
+
+ mDeadline = TimeStamp();
+
+ TimeStamp now = TimeStamp::Now();
+ bool useRefreshDriver = false;
+ if (now >= mStartTime) {
+ // Detect whether the refresh driver is ticking by checking if
+ // GetIdleDeadlineHint returns its input parameter.
+ useRefreshDriver =
+ (nsRefreshDriver::GetIdleDeadlineHint(
+ now, nsRefreshDriver::IdleCheck::OnlyThisProcessRefreshDriver) !=
+ now);
+ } else {
+ NS_WARNING_ASSERTION(!aAllowIdleDispatch,
+ "early callback, or time went backwards");
+ }
+
+ if (useRefreshDriver) {
+ if (!mTask) {
+ // If a task was already scheduled, no point rescheduling.
+ mTask = new IdleTaskRunnerTask(this);
+ // RefreshDriver is ticking, let it schedule the idle dispatch.
+ nsRefreshDriver::DispatchIdleTaskAfterTickUnlessExists(mTask);
+ }
+ // Ensure we get called at some point, even if RefreshDriver is stopped.
+ SetTimerInternal(mMaxDelay);
+ } else {
+ // RefreshDriver doesn't seem to be running.
+ if (aAllowIdleDispatch) {
+ SetTimerInternal(mMaxDelay);
+ if (!mTask) {
+ // If we have mTask we've already scheduled one, and the refresh driver
+ // shouldn't be running if we hit this code path.
+ mTask = new IdleTaskRunnerTask(this);
+ RefPtr<Task> task(mTask);
+ TaskController::Get()->AddTask(task.forget());
+ }
+ } else {
+ if (!mScheduleTimer) {
+ mScheduleTimer = NS_NewTimer();
+ if (!mScheduleTimer) {
+ return;
+ }
+ } else {
+ mScheduleTimer->Cancel();
+ }
+ // We weren't allowed to do idle dispatch immediately, do it after a
+ // short timeout. (Or wait for our start time if we haven't started yet.)
+ uint32_t waitToSchedule = 16; /* ms */
+ if (now < mStartTime) {
+ // + 1 to round milliseconds up to be sure to wait until after
+ // mStartTime.
+ waitToSchedule = (mStartTime - now).ToMilliseconds() + 1;
+ }
+ mScheduleTimer->InitWithNamedFuncCallback(
+ ScheduleTimedOut, this, waitToSchedule,
+ nsITimer::TYPE_ONE_SHOT_LOW_PRIORITY, mName);
+ }
+ }
+}
+
+IdleTaskRunner::~IdleTaskRunner() { CancelTimer(); }
+
+void IdleTaskRunner::CancelTimer() {
+ if (mTask) {
+ nsRefreshDriver::CancelIdleTask(mTask);
+ mTask->Cancel();
+ mTask = nullptr;
+ }
+ if (mTimer) {
+ mTimer->Cancel();
+ }
+ if (mScheduleTimer) {
+ mScheduleTimer->Cancel();
+ }
+ mTimerActive = false;
+}
+
+void IdleTaskRunner::SetTimerInternal(TimeDuration aDelay) {
+ if (mTimerActive) {
+ return;
+ }
+
+ if (!mTimer) {
+ mTimer = NS_NewTimer();
+ } else {
+ mTimer->Cancel();
+ }
+
+ if (mTimer) {
+ mTimer->InitWithNamedFuncCallback(TimedOut, this, aDelay.ToMilliseconds(),
+ nsITimer::TYPE_ONE_SHOT, mName);
+ mTimerActive = true;
+ }
+}
+
+} // end of namespace mozilla