1 /*
 2  * Copyright (c) 2017, 2021, 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
22  * or visit www.oracle.com if you need additional information or have any
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 static final int MAX_EVENTS_TO_POLL = 512;
35 
36     private final int kqfd;
37     private final int filter;
38     private final long address;
39 
40     KQueuePoller(boolean read) throws IOException {
41         this.kqfd = KQueue.create();
42         this.filter = (read) ? EVFILT_READ : EVFILT_WRITE;
43         this.address = KQueue.allocatePollArray(MAX_EVENTS_TO_POLL);
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) {
60         KQueue.register(kqfd, fdVal, filter, EV_DELETE);
61     }
62 
63     @Override
64     int poll(int timeout) throws IOException {
65         int n = KQueue.poll(kqfd, address, MAX_EVENTS_TO_POLL, timeout);
66         int i = 0;
67         while (i < n) {
68             long keventAddress = KQueue.getEvent(address, i);
69             int fdVal = KQueue.getDescriptor(keventAddress);
70             polled(fdVal);
71             i++;
72         }
73         return n;
74     }
75 }