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1 /*
2  * Copyright (C) 2023 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.os;
18 
19 import android.ravenwood.annotation.RavenwoodKeepWholeClass;
20 
21 import java.util.Map;
22 import java.util.concurrent.ConcurrentHashMap;
23 import java.util.concurrent.atomic.AtomicLong;
24 
25 @RavenwoodKeepWholeClass
26 class MessageQueue_ravenwood {
27     private static final AtomicLong sNextId = new AtomicLong(1);
28     private static final Map<Long, MessageQueue_ravenwood> sInstances = new ConcurrentHashMap<>();
29 
30     private boolean mDeleted = false;
31 
32     private final Object mPoller = new Object();
33     private volatile boolean mPolling;
34     private volatile boolean mPendingWake;
35 
validate()36     private void validate() {
37         if (mDeleted) {
38             // TODO: Put more info
39             throw new RuntimeException("MessageQueue already destroyed");
40         }
41     }
42 
getInstance(long id)43     private static MessageQueue_ravenwood getInstance(long id) {
44         MessageQueue_ravenwood q = sInstances.get(id);
45         if (q == null) {
46             throw new RuntimeException("MessageQueue doesn't exist with id=" + id);
47         }
48         q.validate();
49         return q;
50     }
51 
nativeInit()52     public static long nativeInit() {
53         final long id = sNextId.getAndIncrement();
54         final MessageQueue_ravenwood q = new MessageQueue_ravenwood();
55         sInstances.put(id, q);
56         return id;
57     }
58 
nativeDestroy(long ptr)59     public static void nativeDestroy(long ptr) {
60         getInstance(ptr).mDeleted = true;
61         sInstances.remove(ptr);
62     }
63 
nativePollOnce(android.os.MessageQueue queue, long ptr, int timeoutMillis)64     public static void nativePollOnce(android.os.MessageQueue queue, long ptr, int timeoutMillis) {
65         var q = getInstance(ptr);
66         synchronized (q.mPoller) {
67             q.mPolling = true;
68             try {
69                 if (q.mPendingWake) {
70                     // Calling with pending wake returns immediately
71                 } else if (timeoutMillis == 0) {
72                     // Calling epoll_wait() with 0 returns immediately
73                 } else if (timeoutMillis == -1) {
74                     q.mPoller.wait();
75                 } else {
76                     q.mPoller.wait(timeoutMillis);
77                 }
78             } catch (InterruptedException e) {
79                 Thread.currentThread().interrupt();
80             }
81             // Any reason for returning counts as a "wake", so clear pending
82             q.mPendingWake = false;
83             q.mPolling = false;
84         }
85     }
86 
nativeWake(long ptr)87     public static void nativeWake(long ptr) {
88         var q = getInstance(ptr);
89         synchronized (q.mPoller) {
90             q.mPendingWake = true;
91             q.mPoller.notifyAll();
92         }
93     }
94 
nativeIsPolling(long ptr)95     public static boolean nativeIsPolling(long ptr) {
96         var q = getInstance(ptr);
97         return q.mPolling;
98     }
99 
nativeSetFileDescriptorEvents(long ptr, int fd, int events)100     public static void nativeSetFileDescriptorEvents(long ptr, int fd, int events) {
101         throw new UnsupportedOperationException();
102     }
103 }
104