SF: add VSyncDispatch
Add a low level timer primitive to arrange for calling a
callback relative to an anticipated vsync time.
This defines vsync offsets in terms of time remaining until the
targeted vsync event, which is a rate independent definition.
Bug: 140301853
Test: 31 new unit tests
Change-Id: I6ac8f05e4c2107755493b2709551773d0e79c17d
diff --git a/services/surfaceflinger/Scheduler/TimeKeeper.h b/services/surfaceflinger/Scheduler/TimeKeeper.h
new file mode 100644
index 0000000..699cd50
--- /dev/null
+++ b/services/surfaceflinger/Scheduler/TimeKeeper.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2019 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 <utils/Timers.h>
+#include <functional>
+
+namespace android::scheduler {
+
+/*
+ * TimeKeeper is the interface for a single-shot timer primitive.
+ */
+class TimeKeeper {
+public:
+ virtual ~TimeKeeper();
+
+ /*
+ * Arms callback to fired in time nanoseconds.
+ * There is only one timer, and subsequent calls will reset the callback function and the time.
+ */
+ virtual void alarmIn(std::function<void()> const& callback, nsecs_t time) = 0;
+
+ /*
+ * Cancels an existing pending callback
+ */
+ virtual void alarmCancel() = 0;
+
+ /*
+ * Returns the SYSTEM_TIME_MONOTONIC, used by testing infra to stub time.
+ */
+ virtual nsecs_t now() const = 0;
+
+protected:
+ TimeKeeper(TimeKeeper const&) = delete;
+ TimeKeeper& operator=(TimeKeeper const&) = delete;
+ TimeKeeper() = default;
+};
+
+} // namespace android::scheduler