| /* |
| * Copyright (C) 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. |
| */ |
| |
| package android.car; |
| |
| import static com.android.internal.util.Preconditions.checkNotNull; |
| |
| import android.annotation.IntDef; |
| import android.annotation.MainThread; |
| import android.annotation.NonNull; |
| import android.annotation.SystemApi; |
| import android.app.Service; |
| import android.content.Intent; |
| import android.hardware.usb.UsbDevice; |
| import android.os.Bundle; |
| import android.os.Handler; |
| import android.os.IBinder; |
| import android.os.Looper; |
| import android.os.Message; |
| import android.os.Messenger; |
| import android.os.RemoteException; |
| import android.util.Log; |
| |
| import java.io.FileDescriptor; |
| import java.io.PrintWriter; |
| import java.lang.annotation.Retention; |
| import java.lang.annotation.RetentionPolicy; |
| import java.lang.ref.WeakReference; |
| |
| /** |
| * The service that must be implemented by USB AOAP handler system apps. The app must hold the |
| * following permission: {@code android.car.permission.CAR_HANDLE_USB_AOAP_DEVICE}. |
| * |
| * <p>This service gets bound by the framework and the service needs to be protected by |
| * {@code android.car.permission.CAR_HANDLE_USB_AOAP_DEVICE} permission to ensure nobody else can |
| * bind to the service. At most only one client should be bound at a time. |
| * |
| * @hide |
| */ |
| @SystemApi |
| public abstract class AoapService extends Service { |
| private static final String TAG = AoapService.class.getSimpleName(); |
| |
| /** Indicates success or confirmation. */ |
| public static final int RESULT_OK = 0; |
| |
| /** |
| * Indicates that the device is not supported by this service and system shouldn't associate |
| * given device with this service. |
| */ |
| public static final int RESULT_DEVICE_NOT_SUPPORTED = 1; |
| |
| /** |
| * Indicates that device shouldn't be switch to AOAP mode at this time. |
| */ |
| public static final int RESULT_DO_NOT_SWITCH_TO_AOAP = 2; |
| |
| /** @hide */ |
| @IntDef(value = { |
| RESULT_OK, RESULT_DEVICE_NOT_SUPPORTED, RESULT_DO_NOT_SWITCH_TO_AOAP |
| }) |
| @Retention(RetentionPolicy.SOURCE) |
| public @interface Result {} |
| |
| |
| /** |
| * A message sent from the system USB handler service to AOAP handler service to check if the |
| * device is supported. The message must have {@link #KEY_DEVICE} with {@link UsbDevice} object. |
| * |
| * @hide |
| */ |
| public static final int MSG_NEW_DEVICE_ATTACHED = 1; |
| |
| /** |
| * A response message for {@link #MSG_NEW_DEVICE_ATTACHED}. Must contain {@link #KEY_RESULT} |
| * with one of the {@code RESULT_*} constant. |
| * |
| * @hide */ |
| public static final int MSG_NEW_DEVICE_ATTACHED_RESPONSE = 2; |
| |
| /** |
| * A message sent from the system USB handler service to AOAP handler service to check if the |
| * device can be switched to AOAP mode. The message must have {@link #KEY_DEVICE} with |
| * {@link UsbDevice} object. |
| * |
| * @hide |
| */ |
| public static final int MSG_CAN_SWITCH_TO_AOAP = 3; |
| |
| /** |
| * A response message for {@link #MSG_CAN_SWITCH_TO_AOAP}. Must contain {@link #KEY_RESULT} |
| * with one of the {@code RESULT_*} constant. |
| * |
| * @hide */ |
| public static final int MSG_CAN_SWITCH_TO_AOAP_RESPONSE = 4; |
| |
| /** @hide */ |
| public static final String KEY_DEVICE = "usb-device"; |
| |
| /** @hide */ |
| public static final String KEY_RESULT = "result"; |
| |
| |
| /** |
| * Returns {@code true} if the given USB device is supported by this service. |
| * |
| * <p>The device is not expected to be in AOAP mode when this method is called. The purpose of |
| * this method is just to give the service a chance to tell whether based on the information |
| * provided in {@link UsbDevice} class (e.g. PID/VID) this service supports or doesn't support |
| * given device. |
| * |
| * <p>The method must return one of the following status: {@link #RESULT_OK} or |
| * {@link #RESULT_DEVICE_NOT_SUPPORTED} |
| */ |
| @MainThread |
| public abstract @Result int isDeviceSupported(@NonNull UsbDevice device); |
| |
| /** |
| * This method will be called at least once per connection session before switching device into |
| * AOAP mode. |
| * |
| * <p>The device is connected, but not in AOAP mode yet. Implementors of this method may ask |
| * the framework to ignore this device for now and do not switch to AOAP. This may make sense if |
| * a connection to the device has been established through other means, and switching the device |
| * to AOAP would break that connection. |
| * |
| * <p>Note: the method may be called only if this device was claimed to be supported in |
| * {@link #isDeviceSupported(UsbDevice)} method, and this app has been chosen to handle the |
| * device. |
| * |
| * <p>The method must return one of the following status: {@link #RESULT_OK}, |
| * {@link #RESULT_DEVICE_NOT_SUPPORTED} or {@link #RESULT_DO_NOT_SWITCH_TO_AOAP} |
| */ |
| @MainThread |
| public @Result int canSwitchToAoap(@NonNull UsbDevice device) { |
| return RESULT_OK; |
| } |
| |
| private Messenger mMessenger; |
| private boolean mBound; |
| |
| @Override |
| public void onCreate() { |
| super.onCreate(); |
| mMessenger = new Messenger(new IncomingHandler(this)); |
| } |
| |
| @Override |
| public IBinder onBind(Intent intent) { |
| if (mBound) { |
| Log.w(TAG, "Received onBind event when the service was already bound"); |
| } |
| mBound = true; |
| return mMessenger.getBinder(); |
| } |
| |
| @Override |
| public boolean onUnbind(Intent intent) { |
| mBound = false; |
| return super.onUnbind(intent); |
| } |
| |
| @Override |
| protected void dump(FileDescriptor fd, PrintWriter writer, String[] args) { |
| writer.write("Bound: " + mBound); |
| } |
| |
| private static class IncomingHandler extends Handler { |
| private final WeakReference<AoapService> mServiceRef; |
| |
| IncomingHandler(AoapService service) { |
| super(Looper.getMainLooper()); |
| mServiceRef = new WeakReference<>(service); |
| } |
| |
| @Override |
| public void handleMessage(Message msg) { |
| AoapService service = mServiceRef.get(); |
| if (service == null) { |
| return; |
| } |
| Bundle data = msg.getData(); |
| if (data == null) { |
| Log.e(TAG, "Ignoring message " + msg.what + " without data"); |
| return; |
| } |
| |
| Log.i(TAG, "Message received: " + msg.what); |
| |
| switch (msg.what) { |
| case MSG_NEW_DEVICE_ATTACHED: { |
| int res = service.isDeviceSupported( |
| checkNotNull(data.getParcelable(KEY_DEVICE))); |
| if (res != RESULT_OK && res != RESULT_DEVICE_NOT_SUPPORTED) { |
| throw new IllegalArgumentException("Result can not be " + res); |
| } |
| sendResponse(msg.replyTo, MSG_NEW_DEVICE_ATTACHED_RESPONSE, res); |
| break; |
| } |
| |
| case MSG_CAN_SWITCH_TO_AOAP: { |
| int res = service.canSwitchToAoap( |
| checkNotNull(data.getParcelable(KEY_DEVICE))); |
| if (res != RESULT_OK && res != RESULT_DEVICE_NOT_SUPPORTED |
| && res != RESULT_DO_NOT_SWITCH_TO_AOAP) { |
| throw new IllegalArgumentException("Result can not be " + res); |
| } |
| sendResponse(msg.replyTo, MSG_CAN_SWITCH_TO_AOAP_RESPONSE, res); |
| break; |
| } |
| |
| default: |
| Log.e(TAG, "Unknown message received: " + msg.what); |
| break; |
| } |
| } |
| |
| private void sendResponse(Messenger messenger, int msg, int result) { |
| try { |
| messenger.send(createResponseMessage(msg, result)); |
| } catch (RemoteException e) { |
| Log.e(TAG, "Failed to send message", e); |
| } |
| } |
| |
| private Message createResponseMessage(int msg, int result) { |
| Message response = Message.obtain(null, msg); |
| Bundle data = new Bundle(); |
| data.putInt(KEY_RESULT, result); |
| response.setData(data); |
| return response; |
| } |
| } |
| } |