1/*
2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24/*
25 * @test
26 * @bug 8143394
27 * @summary Check for NullPointerException in race between read() and close().
28 */
29import java.io.CharArrayReader;
30import java.io.IOException;
31import java.io.PushbackReader;
32import java.io.Reader;
33import java.io.StringReader;
34import java.util.ArrayList;
35import java.util.List;
36import java.util.concurrent.atomic.AtomicBoolean;
37import java.util.concurrent.atomic.AtomicReference;
38import java.util.function.Supplier;
39
40public class ReadCloseRaceNPE {
41
42    private static final int BUF_SIZE = 1000;
43    private static final long TIMEOUT_MS = 3000;
44
45    private static final List<Exception> failures = new ArrayList<>();
46
47    private static void testReader(final Supplier<Reader> readerSupplier)
48            throws InterruptedException {
49        AtomicReference<Reader> readerRef =
50            new AtomicReference<>(readerSupplier.get());
51
52        AtomicBoolean isFinished = new AtomicBoolean();
53
54        Runnable readTask = () -> {
55            long startTime = System.currentTimeMillis();
56            while (System.currentTimeMillis() - startTime < TIMEOUT_MS) {
57                try {
58                    readerRef.get().read();
59                } catch (Exception e) {
60                    if (!(e instanceof IOException)) {
61                        failures.add(e);
62                        break;
63                    }
64                    readerRef.set(readerSupplier.get());
65                }
66            }
67            isFinished.set(true);
68        };
69
70        Runnable closeTask = () -> {
71            while (!isFinished.get()) {
72                try {
73                    readerRef.get().close();
74                } catch (Exception e) {
75                    if (!(e instanceof IOException)) {
76                        e.printStackTrace();
77                    }
78                }
79            }
80        };
81
82        Thread readThread = new Thread(readTask);
83        Thread closeThread = new Thread(closeTask);
84
85        readThread.start();
86        closeThread.start();
87        readThread.join();
88        closeThread.join();
89    }
90
91    public static void main(String[] args) throws Throwable {
92        final String s = "Two riders were approaching.\\n";
93
94        Supplier<Reader> charPushbackReaderSupplier = () -> {
95            char buf[] = new char[s.length()];
96            s.getChars(0, s.length(), buf, 0);
97            CharArrayReader in = new CharArrayReader(buf);
98            return new PushbackReader(in, BUF_SIZE);
99        };
100
101        testReader(charPushbackReaderSupplier);
102
103        Supplier<Reader> stringPushbackReaderSupplier = () -> {
104            StringReader in = new StringReader(s);
105            return new PushbackReader(in, BUF_SIZE);
106        };
107
108        testReader(stringPushbackReaderSupplier);
109
110        if (!failures.isEmpty()) {
111            failures.stream().forEach((x) -> ((Exception) x).printStackTrace());
112            throw new RuntimeException("PushbackReaderNPE failed");
113        }
114    }
115}
116