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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
17package android.view;
18
19import com.android.internal.util.GrowingArrayUtils;
20
21import android.os.Handler;
22
23import 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 */
30public class HandlerActionQueue {
31    private HandlerAction[] mActions;
32    private int mCount;
33
34    public void post(Runnable action) {
35        postDelayed(action, 0);
36    }
37
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
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
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
95    public int size() {
96        return mCount;
97    }
98
99    public Runnable getRunnable(int index) {
100        if (index >= mCount) {
101            throw new IndexOutOfBoundsException();
102        }
103        return mActions[index].action;
104    }
105
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
117        public HandlerAction(Runnable action, long delay) {
118            this.action = action;
119            this.delay = delay;
120        }
121
122        public boolean matches(Runnable otherAction) {
123            return otherAction == null && action == null
124                    || action != null && action.equals(otherAction);
125        }
126    }
127}
128