SF: Renaming IdleTimer to OneShotTimer
IdleTimer class is used for more than just idle timer, so renaming the
class to a more appropriate name.
Test: manual
Bug: 132811842
Change-Id: Iabfaa28038dc90430a51536ef874618e35ed9014
diff --git a/services/surfaceflinger/Scheduler/OneShotTimer.h b/services/surfaceflinger/Scheduler/OneShotTimer.h
new file mode 100644
index 0000000..fd1aa02
--- /dev/null
+++ b/services/surfaceflinger/Scheduler/OneShotTimer.h
@@ -0,0 +1,94 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <chrono>
+#include <condition_variable>
+#include <thread>
+
+#include <android-base/thread_annotations.h>
+
+namespace android {
+namespace scheduler {
+
+/*
+ * Class that sets off a timer for a given interval, and fires a callback when the
+ * interval expires.
+ */
+class OneShotTimer {
+public:
+ using Interval = std::chrono::milliseconds;
+ using ResetCallback = std::function<void()>;
+ using TimeoutCallback = std::function<void()>;
+
+ OneShotTimer(const Interval& interval, const ResetCallback& resetCallback,
+ const TimeoutCallback& timeoutCallback);
+ ~OneShotTimer();
+
+ // Initializes and turns on the idle timer.
+ void start();
+ // Stops the idle timer and any held resources.
+ void stop();
+ // Resets the wakeup time and fires the reset callback.
+ void reset();
+
+private:
+ // Enum to track in what state is the timer.
+ enum class TimerState {
+ // The internal timer thread has been destroyed, and no state is
+ // tracked.
+ // Possible state transitions: RESET
+ STOPPED = 0,
+ // An external thread has just reset this timer.
+ // If there is a reset callback, then that callback is fired.
+ // Possible state transitions: STOPPED, WAITING
+ RESET = 1,
+ // This timer is waiting for the timeout interval to expire.
+ // Possible state transaitions: STOPPED, RESET, IDLE
+ WAITING = 2,
+ // The timeout interval has expired, so we are sleeping now.
+ // Possible state transaitions: STOPPED, RESET
+ IDLE = 3
+ };
+
+ // Function that loops until the condition for stopping is met.
+ void loop();
+
+ // Thread waiting for timer to expire.
+ std::thread mThread;
+
+ // Condition used to notify mThread.
+ std::condition_variable_any mCondition;
+
+ // Lock used for synchronizing the waiting thread with the application thread.
+ std::mutex mMutex;
+
+ // Current timer state
+ TimerState mState GUARDED_BY(mMutex) = TimerState::RESET;
+
+ // Interval after which timer expires.
+ const Interval mInterval;
+
+ // Callback that happens when timer resets.
+ const ResetCallback mResetCallback;
+
+ // Callback that happens when timer expires.
+ const TimeoutCallback mTimeoutCallback;
+};
+
+} // namespace scheduler
+} // namespace android