1 files changed, 100 insertions, 0 deletions
diff --git a/services/vibratorservice/VibratorCallbackScheduler.cpp b/services/vibratorservice/VibratorCallbackScheduler.cpp
new file mode 100644
index 0000000000..f2870b021d
--- /dev/null
+++ b/services/vibratorservice/VibratorCallbackScheduler.cpp
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+#include <chrono>
+#include <thread>
+
+#include <vibratorservice/VibratorCallbackScheduler.h>
+
+namespace android {
+
+namespace vibrator {
+
+// -------------------------------------------------------------------------------------------------
+
+bool DelayedCallback::isExpired() const {
+    return mExpiration <= std::chrono::steady_clock::now();
+}
+
+DelayedCallback::Timestamp DelayedCallback::getExpiration() const {
+    return mExpiration;
+}
+
+void DelayedCallback::run() const {
+    mCallback();
+}
+
+bool DelayedCallback::operator<(const DelayedCallback& other) const {
+    return mExpiration < other.mExpiration;
+}
+
+bool DelayedCallback::operator>(const DelayedCallback& other) const {
+    return mExpiration > other.mExpiration;
+}
+
+// -------------------------------------------------------------------------------------------------
+
+CallbackScheduler::~CallbackScheduler() {
+    {
+        std::lock_guard<std::mutex> lock(mMutex);
+        mFinished = true;
+    }
+    mCondition.notify_all();
+    if (mCallbackThread && mCallbackThread->joinable()) {
+        mCallbackThread->join();
+    }
+}
+
+void CallbackScheduler::schedule(std::function<void()> callback, std::chrono::milliseconds delay) {
+    {
+        std::lock_guard<std::mutex> lock(mMutex);
+        if (mCallbackThread == nullptr) {
+            mCallbackThread = std::make_unique<std::thread>(&CallbackScheduler::loop, this);
+        }
+        mQueue.emplace(DelayedCallback(callback, delay));
+    }
+    mCondition.notify_all();
+}
+
+void CallbackScheduler::loop() {
+    while (true) {
+        std::unique_lock<std::mutex> lock(mMutex);
+        if (mFinished) {
+            // Destructor was called, so let the callback thread die.
+            break;
+        }
+        while (!mQueue.empty() && mQueue.top().isExpired()) {
+            DelayedCallback callback = mQueue.top();
+            mQueue.pop();
+            lock.unlock();
+            callback.run();
+            lock.lock();
+        }
+        if (mQueue.empty()) {
+            // Wait until a new callback is scheduled.
+            mCondition.wait(mMutex);
+        } else {
+            // Wait until next callback expires, or a new one is scheduled.
+            mCondition.wait_until(mMutex, mQueue.top().getExpiration());
+        }
+    }
+}
+
+// -------------------------------------------------------------------------------------------------
+
+}; // namespace vibrator
+
+}; // namespace android