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1 /*
2  * Copyright (C) 2015 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 android.view;
18 
19 import com.android.internal.util.GrowingArrayUtils;
20 
21 import android.os.Handler;
22 
23 import java.util.ArrayList;
24 
25 /**
26  * Class used to enqueue pending work from Views when no Handler is attached.
27  *
28  * @hide Exposed for test framework only.
29  */
30 public class HandlerActionQueue {
31     private HandlerAction[] mActions;
32     private int mCount;
33 
post(Runnable action)34     public void post(Runnable action) {
35         postDelayed(action, 0);
36     }
37 
postDelayed(Runnable action, long delayMillis)38     public void postDelayed(Runnable action, long delayMillis) {
39         final HandlerAction handlerAction = new HandlerAction(action, delayMillis);
40 
41         synchronized (this) {
42             if (mActions == null) {
43                 mActions = new HandlerAction[4];
44             }
45             mActions = GrowingArrayUtils.append(mActions, mCount, handlerAction);
46             mCount++;
47         }
48     }
49 
removeCallbacks(Runnable action)50     public void removeCallbacks(Runnable action) {
51         synchronized (this) {
52             final int count = mCount;
53             int j = 0;
54 
55             final HandlerAction[] actions = mActions;
56             for (int i = 0; i < count; i++) {
57                 if (actions[i].matches(action)) {
58                     // Remove this action by overwriting it within
59                     // this loop or nulling it out later.
60                     continue;
61                 }
62 
63                 if (j != i) {
64                     // At least one previous entry was removed, so
65                     // this one needs to move to the "new" list.
66                     actions[j] = actions[i];
67                 }
68 
69                 j++;
70             }
71 
72             // The "new" list only has j entries.
73             mCount = j;
74 
75             // Null out any remaining entries.
76             for (; j < count; j++) {
77                 actions[j] = null;
78             }
79         }
80     }
81 
executeActions(Handler handler)82     public void executeActions(Handler handler) {
83         synchronized (this) {
84             final HandlerAction[] actions = mActions;
85             for (int i = 0, count = mCount; i < count; i++) {
86                 final HandlerAction handlerAction = actions[i];
87                 handler.postDelayed(handlerAction.action, handlerAction.delay);
88             }
89 
90             mActions = null;
91             mCount = 0;
92         }
93     }
94 
size()95     public int size() {
96         return mCount;
97     }
98 
getRunnable(int index)99     public Runnable getRunnable(int index) {
100         if (index >= mCount) {
101             throw new IndexOutOfBoundsException();
102         }
103         return mActions[index].action;
104     }
105 
getDelay(int index)106     public long getDelay(int index) {
107         if (index >= mCount) {
108             throw new IndexOutOfBoundsException();
109         }
110         return mActions[index].delay;
111     }
112 
113     private static class HandlerAction {
114         final Runnable action;
115         final long delay;
116 
HandlerAction(Runnable action, long delay)117         public HandlerAction(Runnable action, long delay) {
118             this.action = action;
119             this.delay = delay;
120         }
121 
matches(Runnable otherAction)122         public boolean matches(Runnable otherAction) {
123             return otherAction == null && action == null
124                     || action != null && action.equals(otherAction);
125         }
126     }
127 }
128