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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/. */
+
+#ifndef IdleTaskRunner_h
+#define IdleTaskRunner_h
+
+#include "mozilla/TimeStamp.h"
+#include "nsIEventTarget.h"
+#include "nsISupports.h"
+#include "nsITimer.h"
+#include <functional>
+
+namespace mozilla {
+
+class IdleTaskRunnerTask;
+
+// A general purpose repeating callback runner (it can be configured to a
+// one-time runner, too.) If it is running repeatedly, one has to either
+// explicitly Cancel() the runner or have MayStopProcessing() callback return
+// true to completely remove the runner.
+class IdleTaskRunner {
+ public:
+ friend class IdleTaskRunnerTask;
+ NS_INLINE_DECL_THREADSAFE_REFCOUNTING(IdleTaskRunner)
+
+ // Return true if some meaningful work was done.
+ using CallbackType = std::function<bool(TimeStamp aDeadline)>;
+
+ // A callback for "stop processing" decision. Return true to
+ // stop processing. This can be an alternative to Cancel() or
+ // work together in different way.
+ using MayStopProcessingCallbackType = std::function<bool()>;
+
+ // A callback to be invoked when an interrupt is requested
+ // (eg during an idle activity when the user presses a key.)
+ // The callback takes an "interrupt priority" value as its
+ // sole parameter.
+ using RequestInterruptCallbackType = std::function<void(uint32_t)>;
+
+ public:
+ // An IdleTaskRunner has (up to) three phases:
+ //
+ // - (duration aStartDelay) waiting to run (aStartDelay can be zero)
+ //
+ // - (duration aMaxDelay) attempting to find a long enough amount of idle
+ // time, at least aMinimumUsefulBudget
+ //
+ // - overdue for idle time, run as soon as possible
+ //
+ // If aRepeating is true, then aStartDelay applies only to the first run; the
+ // second run will attempt to run in the first idle slice that is long
+ // enough.
+ //
+ // All durations are in milliseconds.
+ //
+ static already_AddRefed<IdleTaskRunner> Create(
+ const CallbackType& aCallback, const char* aRunnableName,
+ TimeDuration aStartDelay, TimeDuration aMaxDelay,
+ TimeDuration aMinimumUsefulBudget, bool aRepeating,
+ const MayStopProcessingCallbackType& aMayStopProcessing,
+ const RequestInterruptCallbackType& aRequestInterrupt = nullptr);
+
+ void Run();
+
+ // (Used by the task triggering code.) Record the end of the current idle
+ // period, or null if not running during idle time.
+ void SetIdleDeadline(mozilla::TimeStamp aDeadline);
+
+ void SetTimer(TimeDuration aDelay, nsIEventTarget* aTarget);
+
+ // Update the minimum idle time that this callback would be invoked for.
+ void SetMinimumUsefulBudget(int64_t aMinimumUsefulBudget);
+
+ void Cancel();
+
+ void Schedule(bool aAllowIdleDispatch);
+
+ const char* GetName() { return mName; }
+
+ private:
+ explicit IdleTaskRunner(
+ const CallbackType& aCallback, const char* aRunnableName,
+ TimeDuration aStartDelay, TimeDuration aMaxDelay,
+ TimeDuration aMinimumUsefulBudget, bool aRepeating,
+ const MayStopProcessingCallbackType& aMayStopProcessing,
+ const RequestInterruptCallbackType& aRequestInterrupt);
+ ~IdleTaskRunner();
+ void CancelTimer();
+ void SetTimerInternal(TimeDuration aDelay);
+
+ nsCOMPtr<nsITimer> mTimer;
+ nsCOMPtr<nsITimer> mScheduleTimer;
+ CallbackType mCallback;
+
+ // Do not run until this time.
+ const mozilla::TimeStamp mStartTime;
+
+ // Wait this long for idle time before giving up and running a non-idle
+ // callback.
+ TimeDuration mMaxDelay;
+
+ // If running during idle time, the expected end of the current idle period.
+ // The null timestamp when the run is triggered by aMaxDelay instead of idle.
+ TimeStamp mDeadline;
+
+ // The least duration worth calling the callback for during idle time.
+ TimeDuration mMinimumUsefulBudget;
+
+ bool mRepeating;
+ bool mTimerActive;
+ MayStopProcessingCallbackType mMayStopProcessing;
+ RequestInterruptCallbackType mRequestInterrupt;
+ const char* mName;
+ RefPtr<IdleTaskRunnerTask> mTask;
+};
+
+} // end of namespace mozilla.
+
+#endif