1 /*
 2  * Copyright (c) 2017, 2023, 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.  Oracle designates this
 8  * particular file as subject to the "Classpath" exception as provided
 9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20  *
21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23  * questions.
24  */
25 package sun.nio.ch;
26 
27 import java.io.IOException;
28 import static sun.nio.ch.KQueue.*;
29 
30 /**
31  * Poller implementation based on the kqueue facility.
32  */
33 class KQueuePoller extends Poller {
34     private final int kqfd;
35     private final int filter;
36     private final int maxEvents;
37     private final long address;
38 
39     KQueuePoller(boolean subPoller, boolean read) throws IOException {
40         this.kqfd = KQueue.create();
41         this.filter = (read) ? EVFILT_READ : EVFILT_WRITE;
42         this.maxEvents = (subPoller) ? 64 : 512;
43         this.address = KQueue.allocatePollArray(maxEvents);
44     }
45 
46     @Override
47     int fdVal() {
48         return kqfd;
49     }
50 
51     @Override
52     void implRegister(int fdVal) throws IOException {
53         int err = KQueue.register(kqfd, fdVal, filter, (EV_ADD|EV_ONESHOT));
54         if (err != 0)
55             throw new IOException("kevent failed: " + err);
56     }
57 
58     @Override
59     void implDeregister(int fdVal, boolean polled) {
60         // event was deleted if already polled
61         if (!polled) {
62             KQueue.register(kqfd, fdVal, filter, EV_DELETE);
63         }
64     }
65 
66     @Override
67     int poll(int timeout) throws IOException {
68         int n = KQueue.poll(kqfd, address, maxEvents, timeout);
69         int i = 0;
70         while (i < n) {
71             long keventAddress = KQueue.getEvent(address, i);
72             int fdVal = KQueue.getDescriptor(keventAddress);
73             polled(fdVal);
74             i++;
75         }
76         return n;
77     }
78 }