1 /*
2  * Copyright (C) 2016 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 
17 package com.android.server.accessibility;
18 
19 import android.os.Handler;
20 import android.os.Looper;
21 import android.os.Message;
22 import android.util.Pair;
23 
24 import androidx.test.InstrumentationRegistry;
25 
26 import java.util.ArrayList;
27 import java.util.List;
28 
29 /**
30  * Utility class to capture messages dispatched through a handler and control when they arrive
31  * at their target.
32  */
33 public class MessageCapturingHandler extends Handler {
34     List<Pair<Message, Long>> timedMessages = new ArrayList<>();
35 
36     Handler.Callback mCallback;
37 
MessageCapturingHandler(Handler.Callback callback)38     public MessageCapturingHandler(Handler.Callback callback) {
39         this(InstrumentationRegistry.getContext().getMainLooper(), callback);
40     }
41 
MessageCapturingHandler(Looper looper, Callback callback)42     public MessageCapturingHandler(Looper looper, Callback callback) {
43         super(looper);
44         mCallback = callback;
45     }
46 
47     /**
48      * Holding messages in queue, but never dispatching.
49      * @see #removeAllMessages()
50      */
51     @Override
sendMessageAtTime(Message message, long uptimeMillis)52     public boolean sendMessageAtTime(Message message, long uptimeMillis) {
53         timedMessages.add(new Pair<>(Message.obtain(message), uptimeMillis));
54         return super.sendMessageAtTime(message, Long.MAX_VALUE);
55     }
56 
setCallback(Handler.Callback callback)57     public void setCallback(Handler.Callback callback) {
58         mCallback = callback;
59     }
60 
sendOneMessage()61     public void sendOneMessage() {
62         Message message = timedMessages.remove(0).first;
63         removeMessages(message.what, message.obj);
64         dispatchMessage(message);
65         removeStaleMessages();
66     }
67 
sendAllMessages()68     public void sendAllMessages() {
69         while (!timedMessages.isEmpty()) {
70             sendOneMessage();
71         }
72     }
73 
sendLastMessage()74     public void sendLastMessage() {
75         Message message = timedMessages.remove(timedMessages.size() - 1).first;
76         removeMessages(message.what, message.obj);
77         dispatchMessage(message);
78         removeStaleMessages();
79     }
80 
81     /**
82      * Clear messages sent from this handler in queue.
83      * <p>
84      * If main looper is used, this method should be called in tear down function
85      * to ensure messages isolation between test cases.
86      * </p>
87      */
removeAllMessages()88     public void removeAllMessages() {
89         if (hasMessages()) {
90             for (int i = 0; i < timedMessages.size(); i++) {
91                 Message message = timedMessages.get(i).first;
92                 removeMessages(message.what, message.obj);
93             }
94         }
95     }
96 
hasMessages()97     public boolean hasMessages() {
98         removeStaleMessages();
99         return !timedMessages.isEmpty();
100     }
101 
removeStaleMessages()102     private void removeStaleMessages() {
103         for (int i = 0; i < timedMessages.size(); i++) {
104             Message message = timedMessages.get(i).first;
105             if (!hasMessages(message.what, message.obj)) {
106                 timedMessages.remove(i--);
107             }
108         }
109     }
110 
dispatchMessage(Message m)111     public void dispatchMessage(Message m) {
112         if (mCallback != null) {
113             mCallback.handleMessage(m);
114             return;
115         }
116         super.dispatchMessage(m);
117     }
118 }
119