Coverage Summary for Class: OverflowAvoidingLockSupport (com.google.common.util.concurrent)

1 /*
2  * Copyright (C) 2020 The Guava Authors
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5  * in compliance with the License. You may obtain a copy of the License at
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software distributed under the License
10  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11  * or implied. See the License for the specific language governing permissions and limitations under
12  * the License.
13  */
14 
15 package com.google.common.util.concurrent;
16 
17 import static java.lang.Math.min;
18 
19 import java.util.concurrent.locks.LockSupport;
20 import javax.annotation.CheckForNull;
21 
22 /**
23  * Works around an android bug, where parking for more than INT_MAX seconds can produce an abort
24  * signal on 32 bit devices running Android Q.
25  */
26 @ElementTypesAreNonnullByDefault
27 final class OverflowAvoidingLockSupport {
28   // Represents the max nanoseconds representable on a linux timespec with a 32 bit tv_sec
29   static final long MAX_NANOSECONDS_THRESHOLD = (1L + Integer.MAX_VALUE) * 1_000_000_000L - 1L;
30 
31   private OverflowAvoidingLockSupport() {}
32 
33   static void parkNanos(@CheckForNull Object blocker, long nanos) {
34     // Even in the extremely unlikely event that a thread unblocks itself early after only 68 years,
35     // this is indistinguishable from a spurious wakeup, which LockSupport allows.
36     LockSupport.parkNanos(blocker, min(nanos, MAX_NANOSECONDS_THRESHOLD));
37   }
38 }