Add RecurrentTimer for VHAL.
Add a RecurrentTimer that allows registering recurrent actions.
Test: atest DefaultVehicleHalTest
Bug: 200737967
Change-Id: I0d62c554bb8de404d9e9634ff8118c64ebf3c864
diff --git a/automotive/vehicle/aidl/impl/vhal/Android.bp b/automotive/vehicle/aidl/impl/vhal/Android.bp
index a54ab4b..eaa23dc 100644
--- a/automotive/vehicle/aidl/impl/vhal/Android.bp
+++ b/automotive/vehicle/aidl/impl/vhal/Android.bp
@@ -57,6 +57,7 @@
"src/ConnectedClient.cpp",
"src/DefaultVehicleHal.cpp",
"src/PendingRequestPool.cpp",
+ "src/RecurrentTimer.cpp",
],
static_libs: [
"VehicleHalUtils",
diff --git a/automotive/vehicle/aidl/impl/vhal/include/RecurrentTimer.h b/automotive/vehicle/aidl/impl/vhal/include/RecurrentTimer.h
new file mode 100644
index 0000000..5f0f716
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/vhal/include/RecurrentTimer.h
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#ifndef android_hardware_automotive_vehicle_aidl_impl_vhal_include_RecurrentTimer_H_
+#define android_hardware_automotive_vehicle_aidl_impl_vhal_include_RecurrentTimer_H_
+
+#include <android-base/thread_annotations.h>
+
+#include <memory>
+#include <mutex>
+#include <queue>
+#include <thread>
+#include <unordered_map>
+#include <vector>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+
+// A thread-safe recurrent timer.
+class RecurrentTimer final {
+ public:
+ // The class for the function that would be called recurrently.
+ using Callback = std::function<void()>;
+
+ RecurrentTimer();
+
+ ~RecurrentTimer();
+
+ // Registers a recurrent callback for a given interval.
+ // Registering the same callback twice will override the interval provided before.
+ void registerTimerCallback(int64_t intervalInNano, std::shared_ptr<Callback> callback);
+
+ // Unregisters a previously registered recurrent callback.
+ void unregisterTimerCallback(std::shared_ptr<Callback> callback);
+
+ private:
+ // friend class for unit testing.
+ friend class RecurrentTimerTest;
+
+ struct CallbackInfo {
+ std::shared_ptr<Callback> callback;
+ int64_t interval;
+ int64_t nextTime;
+ // A flag to indicate whether this CallbackInfo is already outdated and should be ignored.
+ // The reason we need this flag is because we cannot easily remove an element from a heap.
+ bool outdated = false;
+
+ static bool cmp(const std::unique_ptr<CallbackInfo>& lhs,
+ const std::unique_ptr<CallbackInfo>& rhs);
+ };
+
+ std::mutex mLock;
+ std::thread mThread;
+ std::condition_variable mCond;
+ bool mStopRequested GUARDED_BY(mLock) = false;
+ // A map to map each callback to its current active CallbackInfo in the mCallbackQueue.
+ std::unordered_map<std::shared_ptr<Callback>, CallbackInfo*> mCallbacks GUARDED_BY(mLock);
+ // A min-heap sorted by nextTime. Note that because we cannot remove arbitrary element from the
+ // heap, a single Callback can have multiple entries in this queue, all but one should be valid.
+ // The rest should be mark as outdated. The valid one is one stored in mCallbacks.
+ std::vector<std::unique_ptr<CallbackInfo>> mCallbackQueue GUARDED_BY(mLock);
+
+ void loop();
+
+ // Mark the callbackInfo as outdated and should be ignored when popped from the heap.
+ void markOutdatedLocked(CallbackInfo* callback) REQUIRES(mLock);
+ // Remove all outdated callbackInfos from the top of the heap. This function must be called
+ // each time we might introduce outdated elements to the top. We must make sure the heap is
+ // always valid from the top.
+ void removeInvalidCallbackLocked() REQUIRES(mLock);
+ // Pops the next closest callback (must be valid) from the heap.
+ std::unique_ptr<CallbackInfo> popNextCallbackLocked() REQUIRES(mLock);
+};
+
+} // namespace vehicle
+} // namespace automotive
+} // namespace hardware
+} // namespace android
+
+#endif // android_hardware_automotive_vehicle_aidl_impl_vhal_include_RecurrentTimer_H_
diff --git a/automotive/vehicle/aidl/impl/vhal/src/RecurrentTimer.cpp b/automotive/vehicle/aidl/impl/vhal/src/RecurrentTimer.cpp
new file mode 100644
index 0000000..8521c4d
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/vhal/src/RecurrentTimer.cpp
@@ -0,0 +1,177 @@
+/*
+ * Copyright (C) 2021 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 "RecurrentTimer.h"
+
+#include <utils/Log.h>
+#include <utils/SystemClock.h>
+
+#include <inttypes.h>
+#include <math.h>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+
+using ::android::base::ScopedLockAssertion;
+
+RecurrentTimer::RecurrentTimer() : mThread(&RecurrentTimer::loop, this) {}
+
+RecurrentTimer::~RecurrentTimer() {
+ {
+ std::scoped_lock<std::mutex> lockGuard(mLock);
+ mStopRequested = true;
+ }
+ mCond.notify_one();
+ if (mThread.joinable()) {
+ mThread.join();
+ }
+}
+
+void RecurrentTimer::registerTimerCallback(int64_t intervalInNano,
+ std::shared_ptr<RecurrentTimer::Callback> callback) {
+ {
+ std::scoped_lock<std::mutex> lockGuard(mLock);
+
+ // Aligns the nextTime to multiply of interval.
+ int64_t nextTime = ceil(elapsedRealtimeNano() / intervalInNano) * intervalInNano;
+
+ std::unique_ptr<CallbackInfo> info = std::make_unique<CallbackInfo>();
+ info->callback = callback;
+ info->interval = intervalInNano;
+ info->nextTime = nextTime;
+
+ auto it = mCallbacks.find(callback);
+ if (it != mCallbacks.end()) {
+ ALOGI("Replacing an existing timer callback with a new interval, current: %" PRId64
+ " ns, new: %" PRId64 " ns",
+ it->second->interval, intervalInNano);
+ markOutdatedLocked(it->second);
+ }
+ mCallbacks[callback] = info.get();
+ mCallbackQueue.push_back(std::move(info));
+ // Insert the last element into the heap.
+ std::push_heap(mCallbackQueue.begin(), mCallbackQueue.end(), CallbackInfo::cmp);
+ }
+ mCond.notify_one();
+}
+
+void RecurrentTimer::unregisterTimerCallback(std::shared_ptr<RecurrentTimer::Callback> callback) {
+ {
+ std::scoped_lock<std::mutex> lockGuard(mLock);
+
+ auto it = mCallbacks.find(callback);
+ if (it == mCallbacks.end()) {
+ ALOGE("No event found to unregister");
+ return;
+ }
+
+ markOutdatedLocked(it->second);
+ mCallbacks.erase(it);
+ }
+
+ mCond.notify_one();
+}
+
+void RecurrentTimer::markOutdatedLocked(RecurrentTimer::CallbackInfo* info) {
+ info->outdated = true;
+ info->callback = nullptr;
+ // Make sure the first element is always valid.
+ removeInvalidCallbackLocked();
+}
+
+void RecurrentTimer::removeInvalidCallbackLocked() {
+ while (mCallbackQueue.size() != 0 && mCallbackQueue[0]->outdated) {
+ std::pop_heap(mCallbackQueue.begin(), mCallbackQueue.end(), CallbackInfo::cmp);
+ mCallbackQueue.pop_back();
+ }
+}
+
+std::unique_ptr<RecurrentTimer::CallbackInfo> RecurrentTimer::popNextCallbackLocked() {
+ std::pop_heap(mCallbackQueue.begin(), mCallbackQueue.end(), CallbackInfo::cmp);
+ std::unique_ptr<CallbackInfo> info = std::move(mCallbackQueue[mCallbackQueue.size() - 1]);
+ mCallbackQueue.pop_back();
+ // Make sure the first element is always valid.
+ removeInvalidCallbackLocked();
+ return info;
+}
+
+void RecurrentTimer::loop() {
+ std::unique_lock<std::mutex> uniqueLock(mLock);
+
+ while (true) {
+ // Wait until the timer exits or we have at least one recurrent callback.
+ mCond.wait(uniqueLock, [this] {
+ ScopedLockAssertion lockAssertion(mLock);
+ return mStopRequested || mCallbackQueue.size() != 0;
+ });
+
+ int64_t interval;
+ {
+ ScopedLockAssertion lockAssertion(mLock);
+ if (mStopRequested) {
+ return;
+ }
+ // The first element is the nearest next event.
+ int64_t nextTime = mCallbackQueue[0]->nextTime;
+ int64_t now = elapsedRealtimeNano();
+ if (nextTime > now) {
+ interval = nextTime - now;
+ } else {
+ interval = 0;
+ }
+ }
+
+ // Wait for the next event or the timer exits.
+ if (mCond.wait_for(uniqueLock, std::chrono::nanoseconds(interval), [this] {
+ ScopedLockAssertion lockAssertion(mLock);
+ return mStopRequested;
+ })) {
+ return;
+ }
+
+ {
+ ScopedLockAssertion lockAssertion(mLock);
+ int64_t now = elapsedRealtimeNano();
+ while (mCallbackQueue.size() > 0) {
+ int64_t nextTime = mCallbackQueue[0]->nextTime;
+ if (nextTime > now) {
+ break;
+ }
+
+ std::unique_ptr<CallbackInfo> info = popNextCallbackLocked();
+ info->nextTime += info->interval;
+
+ auto callback = info->callback;
+ mCallbackQueue.push_back(std::move(info));
+ std::push_heap(mCallbackQueue.begin(), mCallbackQueue.end(), CallbackInfo::cmp);
+
+ (*callback)();
+ }
+ }
+ }
+}
+
+bool RecurrentTimer::CallbackInfo::cmp(const std::unique_ptr<RecurrentTimer::CallbackInfo>& lhs,
+ const std::unique_ptr<RecurrentTimer::CallbackInfo>& rhs) {
+ return lhs->nextTime > rhs->nextTime;
+}
+
+} // namespace vehicle
+} // namespace automotive
+} // namespace hardware
+} // namespace android
diff --git a/automotive/vehicle/aidl/impl/vhal/test/RecurrentTimerTest.cpp b/automotive/vehicle/aidl/impl/vhal/test/RecurrentTimerTest.cpp
new file mode 100644
index 0000000..d343cea
--- /dev/null
+++ b/automotive/vehicle/aidl/impl/vhal/test/RecurrentTimerTest.cpp
@@ -0,0 +1,192 @@
+/*
+ * Copyright (C) 2021 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 "RecurrentTimer.h"
+
+#include <android-base/thread_annotations.h>
+#include <gtest/gtest.h>
+
+#include <chrono>
+#include <memory>
+#include <mutex>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace vehicle {
+
+class RecurrentTimerTest : public ::testing::Test {
+ public:
+ std::shared_ptr<RecurrentTimer::Callback> getCallback(size_t token) {
+ return std::make_shared<RecurrentTimer::Callback>([this, token] {
+ std::scoped_lock<std::mutex> lockGuard(mLock);
+
+ mCallbacks.push_back(token);
+ });
+ }
+
+ std::vector<size_t> getCalledCallbacks() {
+ std::scoped_lock<std::mutex> lockGuard(mLock);
+ return mCallbacks;
+ }
+
+ void clearCalledCallbacks() {
+ std::scoped_lock<std::mutex> lockGuard(mLock);
+ mCallbacks.clear();
+ }
+
+ size_t countTimerCallbackQueue(RecurrentTimer* timer) {
+ std::scoped_lock<std::mutex> lockGuard(timer->mLock);
+ return timer->mCallbackQueue.size();
+ }
+
+ private:
+ std::mutex mLock;
+ std::vector<size_t> mCallbacks GUARDED_BY(mLock);
+};
+
+TEST_F(RecurrentTimerTest, testRegisterCallback) {
+ RecurrentTimer timer;
+ // 0.1s
+ int64_t interval = 100000000;
+
+ auto action = getCallback(0);
+ timer.registerTimerCallback(interval, action);
+
+ std::this_thread::sleep_for(std::chrono::seconds(1));
+
+ timer.unregisterTimerCallback(action);
+
+ // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+ ASSERT_GE(getCalledCallbacks().size(), static_cast<size_t>(9));
+}
+
+TEST_F(RecurrentTimerTest, testRegisterUnregisterRegister) {
+ RecurrentTimer timer;
+ // 0.1s
+ int64_t interval = 100000000;
+
+ auto action = getCallback(0);
+ timer.registerTimerCallback(interval, action);
+
+ std::this_thread::sleep_for(std::chrono::milliseconds(200));
+
+ timer.unregisterTimerCallback(action);
+
+ std::this_thread::sleep_for(std::chrono::milliseconds(200));
+
+ clearCalledCallbacks();
+
+ timer.registerTimerCallback(interval, action);
+
+ std::this_thread::sleep_for(std::chrono::seconds(1));
+
+ // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+ ASSERT_GE(getCalledCallbacks().size(), static_cast<size_t>(9));
+}
+
+TEST_F(RecurrentTimerTest, testDestroyTimerWithCallback) {
+ std::unique_ptr<RecurrentTimer> timer = std::make_unique<RecurrentTimer>();
+ // 0.1s
+ int64_t interval = 100000000;
+
+ auto action = getCallback(0);
+ timer->registerTimerCallback(interval, action);
+
+ std::this_thread::sleep_for(std::chrono::milliseconds(200));
+
+ timer.reset();
+
+ clearCalledCallbacks();
+
+ std::this_thread::sleep_for(std::chrono::milliseconds(200));
+
+ ASSERT_TRUE(getCalledCallbacks().empty());
+}
+
+TEST_F(RecurrentTimerTest, testRegisterMultipleCallbacks) {
+ RecurrentTimer timer;
+ // 0.1s
+ int64_t interval1 = 100000000;
+ auto action1 = getCallback(1);
+ timer.registerTimerCallback(interval1, action1);
+ // 0.05s
+ int64_t interval2 = 50000000;
+ auto action2 = getCallback(2);
+ timer.registerTimerCallback(interval2, action2);
+ // 0.03s
+ int64_t interval3 = 30000000;
+ auto action3 = getCallback(3);
+ timer.registerTimerCallback(interval3, action3);
+
+ std::this_thread::sleep_for(std::chrono::seconds(1));
+
+ timer.unregisterTimerCallback(action1);
+ timer.unregisterTimerCallback(action2);
+ timer.unregisterTimerCallback(action3);
+
+ size_t action1Count = 0;
+ size_t action2Count = 0;
+ size_t action3Count = 0;
+ for (size_t token : getCalledCallbacks()) {
+ if (token == 1) {
+ action1Count++;
+ }
+ if (token == 2) {
+ action2Count++;
+ }
+ if (token == 3) {
+ action3Count++;
+ }
+ }
+ // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+ ASSERT_GE(action1Count, static_cast<size_t>(9));
+ // Theoretically trigger 20 times, but check for at least 15 times to be stable.
+ ASSERT_GE(action2Count, static_cast<size_t>(15));
+ // Theoretically trigger 33 times, but check for at least 25 times to be stable.
+ ASSERT_GE(action3Count, static_cast<size_t>(25));
+}
+
+TEST_F(RecurrentTimerTest, testRegisterSameCallbackMultipleTimes) {
+ RecurrentTimer timer;
+ // 0.02s
+ int64_t interval1 = 20000000;
+ // 0.01s
+ int64_t interval2 = 10000000;
+
+ auto action = getCallback(0);
+ for (int i = 0; i < 10; i++) {
+ timer.registerTimerCallback(interval1, action);
+ timer.registerTimerCallback(interval2, action);
+ }
+
+ clearCalledCallbacks();
+
+ std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+ // Theoretically trigger 10 times, but check for at least 9 times to be stable.
+ ASSERT_GE(getCalledCallbacks().size(), static_cast<size_t>(9));
+
+ timer.unregisterTimerCallback(action);
+
+ // Make sure there is no item in the callback queue.
+ ASSERT_EQ(countTimerCallbackQueue(&timer), static_cast<size_t>(0));
+}
+
+} // namespace vehicle
+} // namespace automotive
+} // namespace hardware
+} // namespace android