| /* |
| * Copyright (C) 2014 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.support.test.espresso.base; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.base.Preconditions.checkState; |
| import static com.google.common.base.Throwables.propagate; |
| |
| import android.os.Handler; |
| import android.os.Looper; |
| import android.os.Message; |
| import android.os.MessageQueue; |
| import android.os.SystemClock; |
| import android.util.Log; |
| |
| import java.lang.reflect.Field; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import java.util.concurrent.Callable; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.FutureTask; |
| |
| /** |
| * Isolates the nasty details of touching the message queue. |
| */ |
| final class QueueInterrogator { |
| |
| enum QueueState { EMPTY, TASK_DUE_SOON, TASK_DUE_LONG, BARRIER }; |
| |
| private static final String TAG = "QueueInterrogator"; |
| |
| private static final Method messageQueueNextMethod; |
| private static final Field messageQueueHeadField; |
| private static final int LOOKAHEAD_MILLIS = 15; |
| |
| private final Looper interrogatedLooper; |
| private volatile MessageQueue interrogatedQueue; |
| |
| static { |
| Method nextMethod = null; |
| Field headField = null; |
| try { |
| nextMethod = MessageQueue.class.getDeclaredMethod("next"); |
| nextMethod.setAccessible(true); |
| |
| headField = MessageQueue.class.getDeclaredField("mMessages"); |
| headField.setAccessible(true); |
| } catch (IllegalArgumentException e) { |
| nextMethod = null; |
| headField = null; |
| Log.e(TAG, "Could not initialize interrogator!", e); |
| } catch (NoSuchFieldException e) { |
| nextMethod = null; |
| headField = null; |
| Log.e(TAG, "Could not initialize interrogator!", e); |
| } catch (NoSuchMethodException e) { |
| nextMethod = null; |
| headField = null; |
| Log.e(TAG, "Could not initialize interrogator!", e); |
| } catch (SecurityException e) { |
| nextMethod = null; |
| headField = null; |
| Log.e(TAG, "Could not initialize interrogator!", e); |
| } finally { |
| messageQueueNextMethod = nextMethod; |
| messageQueueHeadField = headField; |
| } |
| } |
| |
| QueueInterrogator(Looper interrogatedLooper) { |
| this.interrogatedLooper = checkNotNull(interrogatedLooper); |
| checkNotNull(messageQueueHeadField); |
| checkNotNull(messageQueueNextMethod); |
| } |
| |
| // Only for use by espresso - keep package private. |
| Message getNextMessage() { |
| checkThread(); |
| |
| if (null == interrogatedQueue) { |
| initializeQueue(); |
| } |
| |
| try { |
| return (Message) messageQueueNextMethod.invoke(Looper.myQueue()); |
| } catch (IllegalAccessException e) { |
| throw propagate(e); |
| } catch (IllegalArgumentException e) { |
| throw propagate(e); |
| } catch (InvocationTargetException e) { |
| throw propagate(e); |
| } catch (SecurityException e) { |
| throw propagate(e); |
| } |
| } |
| |
| QueueState determineQueueState() { |
| // may be called from any thread. |
| |
| if (null == interrogatedQueue) { |
| initializeQueue(); |
| } |
| synchronized (interrogatedQueue) { |
| try { |
| Message head = (Message) messageQueueHeadField.get(interrogatedQueue); |
| if (null == head) { |
| // no messages pending - AT ALL! |
| return QueueState.EMPTY; |
| } |
| if (null == head.getTarget()) { |
| // null target is a sync barrier token. |
| return QueueState.BARRIER; |
| } else { |
| long headWhen = head.getWhen(); |
| long nowFuz = SystemClock.uptimeMillis() + LOOKAHEAD_MILLIS; |
| |
| if (nowFuz > headWhen) { |
| return QueueState.TASK_DUE_SOON; |
| } else { |
| return QueueState.TASK_DUE_LONG; |
| } |
| } |
| } catch (IllegalAccessException e) { |
| throw propagate(e); |
| } |
| } |
| } |
| |
| private void initializeQueue() { |
| if (interrogatedLooper == Looper.myLooper()) { |
| interrogatedQueue = Looper.myQueue(); |
| } else { |
| Handler oneShotHandler = new Handler(interrogatedLooper); |
| FutureTask<MessageQueue> queueCapture = new FutureTask<MessageQueue>( |
| new Callable<MessageQueue>() { |
| @Override |
| public MessageQueue call() { |
| return Looper.myQueue(); |
| } |
| }); |
| oneShotHandler.postAtFrontOfQueue(queueCapture); |
| try { |
| interrogatedQueue = queueCapture.get(); |
| } catch (ExecutionException ee) { |
| throw propagate(ee.getCause()); |
| } catch (InterruptedException ie) { |
| throw propagate(ie); |
| } |
| } |
| } |
| |
| private void checkThread() { |
| checkState(interrogatedLooper == Looper.myLooper(), "Calling from non-owning thread!"); |
| } |
| } |