1 files changed, 121 insertions, 0 deletions
diff --git a/services/vibratorservice/include/vibratorservice/VibratorHalController.h b/services/vibratorservice/include/vibratorservice/VibratorHalController.h
new file mode 100644
index 0000000000..6c31e2b882
--- /dev/null
+++ b/services/vibratorservice/include/vibratorservice/VibratorHalController.h
@@ -0,0 +1,121 @@
+/*
+ * 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.
+ */
+
+#ifndef ANDROID_OS_VIBRATORHALCONTROLLER_H
+#define ANDROID_OS_VIBRATORHALCONTROLLER_H
+
+#include <android-base/thread_annotations.h>
+#include <android/hardware/vibrator/IVibrator.h>
+
+#include <vibratorservice/VibratorCallbackScheduler.h>
+#include <vibratorservice/VibratorHalWrapper.h>
+
+namespace android {
+
+namespace vibrator {
+
+std::shared_ptr<HalWrapper> connectHal(std::shared_ptr<CallbackScheduler> scheduler);
+
+template <typename T>
+using HalFunction = std::function<T(HalWrapper*)>;
+
+// Controller for Vibrator HAL handle.
+// This relies on a given Connector to connect to the underlying Vibrator HAL service and reconnects
+// after each failed api call. This also ensures connecting to the service is thread-safe.
+class HalController {
+public:
+    using Connector =
+            std::function<std::shared_ptr<HalWrapper>(std::shared_ptr<CallbackScheduler>)>;
+
+    HalController() : HalController(std::make_shared<CallbackScheduler>(), &connectHal) {}
+    HalController(std::shared_ptr<CallbackScheduler> callbackScheduler, Connector connector)
+          : mConnector(connector),
+            mConnectedHal(nullptr),
+            mCallbackScheduler(std::move(callbackScheduler)) {}
+    virtual ~HalController() = default;
+
+    /* Connects to the newest HAL version available, possibly waiting for the registered service to
+     * become available. This will automatically be called at the first API usage if it was not
+     * manually called beforehand. Calling this manually during the setup phase can avoid slowing
+     * the first API call later on. Returns true if any HAL version is available, false otherwise.
+     */
+    virtual bool init();
+
+    /* Reloads HAL service instance without waiting. This relies on the HAL version found by init()
+     * to rapidly reconnect to the specific HAL service, or defers to init() if it was never called.
+     */
+    virtual void tryReconnect();
+
+    /* Returns info loaded from the connected HAL. This allows partial results to be returned if any
+     * of the Info fields has failed, but also retried on any failure.
+     */
+    Info getInfo() {
+        static Info sDefaultInfo = InfoCache().get();
+        return apply<Info>([](HalWrapper* hal) { return hal->getInfo(); }, sDefaultInfo, "getInfo");
+    }
+
+    /* Calls given HAL function, applying automatic retries to reconnect with the HAL when the
+     * result has failed. Parameter functionName is for logging purposes.
+     */
+    template <typename T>
+    HalResult<T> doWithRetry(const HalFunction<HalResult<T>>& halFn, const char* functionName) {
+        return apply(halFn, HalResult<T>::unsupported(), functionName);
+    }
+
+private:
+    static constexpr int MAX_RETRIES = 1;
+
+    Connector mConnector;
+    std::mutex mConnectedHalMutex;
+    // Shared pointer to allow local copies to be used by different threads.
+    std::shared_ptr<HalWrapper> mConnectedHal GUARDED_BY(mConnectedHalMutex);
+    // Shared pointer to allow copies to be passed to possible recreated mConnectedHal instances.
+    std::shared_ptr<CallbackScheduler> mCallbackScheduler;
+
+    /* Calls given HAL function, applying automatic retries to reconnect with the HAL when the
+     * result has failed. Given default value is returned when no HAL is available, and given
+     * function name is for logging purposes.
+     */
+    template <typename T>
+    T apply(const HalFunction<T>& halFn, T defaultValue, const char* functionName) {
+        if (!init()) {
+            ALOGV("Skipped %s because Vibrator HAL is not available", functionName);
+            return defaultValue;
+        }
+        std::shared_ptr<HalWrapper> hal;
+        {
+            std::lock_guard<std::mutex> lock(mConnectedHalMutex);
+            hal = mConnectedHal;
+        }
+
+        for (int i = 0; i < MAX_RETRIES; i++) {
+            T result = halFn(hal.get());
+            if (result.checkAndLogFailure(functionName)) {
+                tryReconnect();
+            } else {
+                return result;
+            }
+        }
+
+        return halFn(hal.get());
+    }
+};
+
+}; // namespace vibrator
+
+}; // namespace android
+
+#endif // ANDROID_OS_VIBRATORHALCONTROLLER_H