1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *   http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.android.apps.common.testing.ui.espresso.base;
18
19import static com.google.common.base.Preconditions.checkNotNull;
20import static com.google.common.base.Preconditions.checkState;
21
22import com.google.android.apps.common.testing.ui.espresso.IdlingResource;
23import com.google.android.apps.common.testing.ui.espresso.IdlingResource.ResourceCallback;
24import com.google.android.apps.common.testing.ui.espresso.base.QueueInterrogator.QueueState;
25
26import android.os.Handler;
27import android.os.Looper;
28import android.os.MessageQueue.IdleHandler;
29
30/**
31 * An Idling Resource Adapter for Loopers.
32 */
33final class LooperIdlingResource implements IdlingResource {
34
35  private static final String TAG = "LooperIdleResource";
36
37  private final boolean considerWaitIdle;
38  private final Looper monitoredLooper;
39  private final Handler monitoredHandler;
40
41  private ResourceCallback resourceCallback;
42
43  LooperIdlingResource(Looper monitoredLooper, boolean considerWaitIdle) {
44    this.monitoredLooper = checkNotNull(monitoredLooper);
45    this.monitoredHandler = new Handler(monitoredLooper);
46    this.considerWaitIdle = considerWaitIdle;
47    checkState(Looper.getMainLooper() != monitoredLooper, "Not for use with main looper.");
48  }
49
50  // Only assigned and read from the main loop.
51  private QueueInterrogator queueInterrogator;
52
53  @Override
54  public String getName() {
55    return monitoredLooper.getThread().getName();
56  }
57
58  @Override
59  public boolean isIdleNow() {
60    // on main thread here.
61    QueueState state = queueInterrogator.determineQueueState();
62    boolean idle = state == QueueState.EMPTY || state == QueueState.TASK_DUE_LONG;
63    boolean idleWait = considerWaitIdle
64        && monitoredLooper.getThread().getState() == Thread.State.WAITING;
65    if (idleWait) {
66      if (resourceCallback != null) {
67        resourceCallback.onTransitionToIdle();
68      }
69    }
70    return idle || idleWait;
71  }
72
73  @Override
74  public void registerIdleTransitionCallback(ResourceCallback resourceCallback) {
75    this.resourceCallback = resourceCallback;
76    // on main thread here.
77    queueInterrogator = new QueueInterrogator(monitoredLooper);
78
79    // must load idle handlers from monitored looper thread.
80    IdleHandler idleHandler = new ResourceCallbackIdleHandler(resourceCallback, queueInterrogator,
81        monitoredHandler);
82
83    checkState(monitoredHandler.postAtFrontOfQueue(new Initializer(idleHandler)),
84          "Monitored looper exiting.");
85  }
86
87  private static class ResourceCallbackIdleHandler implements IdleHandler {
88    private final ResourceCallback resourceCallback;
89    private final QueueInterrogator myInterrogator;
90    private final Handler myHandler;
91
92    ResourceCallbackIdleHandler(ResourceCallback resourceCallback,
93        QueueInterrogator myInterrogator, Handler myHandler) {
94      this.resourceCallback = checkNotNull(resourceCallback);
95      this.myInterrogator = checkNotNull(myInterrogator);
96      this.myHandler = checkNotNull(myHandler);
97    }
98
99    @Override
100    public boolean queueIdle() {
101      // invoked on the monitored looper thread.
102      QueueState queueState = myInterrogator.determineQueueState();
103      if (queueState == QueueState.EMPTY || queueState == QueueState.TASK_DUE_LONG) {
104        // no block and no task coming 'shortly'.
105        resourceCallback.onTransitionToIdle();
106      } else if (queueState == QueueState.BARRIER) {
107        // send a sentinal message that'll cause us to queueIdle again once the
108        // block is lifted.
109        myHandler.sendEmptyMessage(-1);
110      }
111
112      return true;
113    }
114  }
115
116  private static class Initializer implements Runnable {
117    private final IdleHandler myIdleHandler;
118
119    Initializer(IdleHandler myIdleHandler) {
120      this.myIdleHandler = checkNotNull(myIdleHandler);
121    }
122
123    @Override
124    public void run() {
125      // on monitored looper thread.
126      Looper.myQueue().addIdleHandler(myIdleHandler);
127    }
128  }
129
130}
131