blob: 671f2d496e638b2cac8585f0d83ef8628655ca2d (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
|
/*
* Copyright (C) 2010 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.util;
import java.lang.ref.PhantomReference;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
/**
* This class can be used to implement reliable finalizers.
*
* @hide
*/
public final class Finalizers {
private static final String LOG_TAG = "Finalizers";
private static final Object[] sLock = new Object[0];
private static boolean sInit;
private static Reclaimer sReclaimer;
/**
* Subclass of PhantomReference used to reclaim resources.
*/
public static abstract class ReclaimableReference<T> extends PhantomReference<T> {
public ReclaimableReference(T r, ReferenceQueue<Object> q) {
super(r, q);
}
public abstract void reclaim();
}
/**
* Returns the queue used to reclaim ReclaimableReferences.
*
* @return A reference queue or null before initialization
*/
public static ReferenceQueue<Object> getQueue() {
synchronized (sLock) {
if (!sInit) {
return null;
}
if (!sReclaimer.isRunning()) {
sReclaimer = new Reclaimer(sReclaimer.mQueue);
sReclaimer.start();
}
return sReclaimer.mQueue;
}
}
/**
* Invoked by Zygote. Don't touch!
*/
public static void init() {
synchronized (sLock) {
if (!sInit && sReclaimer == null) {
sReclaimer = new Reclaimer();
sReclaimer.start();
sInit = true;
}
}
}
private static class Reclaimer extends Thread {
ReferenceQueue<Object> mQueue;
private volatile boolean mRunning = false;
Reclaimer() {
this(new ReferenceQueue<Object>());
}
Reclaimer(ReferenceQueue<Object> queue) {
super("Reclaimer");
setDaemon(true);
mQueue = queue;
}
@Override
public void start() {
mRunning = true;
super.start();
}
boolean isRunning() {
return mRunning;
}
@SuppressWarnings({"InfiniteLoopStatement"})
@Override
public void run() {
try {
while (true) {
try {
cleanUp(mQueue.remove());
} catch (InterruptedException e) {
// Ignore
}
}
} catch (Exception e) {
Log.e(LOG_TAG, "Reclaimer thread exiting: ", e);
} finally {
mRunning = false;
}
}
private void cleanUp(Reference<?> reference) {
do {
reference.clear();
((ReclaimableReference<?>) reference).reclaim();
} while ((reference = mQueue.poll()) != null);
}
}
}
|
