1 /*
2 * Copyright (c) 2001, 2018, 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
26 package sun.nio.ch;
27
28 import java.io.IOException;
29 import java.nio.channels.*;
30 import java.nio.channels.spi.*;
31 import java.util.*;
32
33
34 /**
35 * An abstract selector impl.
36 */
37
38 abstract class AbstractPollSelectorImpl
39 extends SelectorImpl
40 {
41
42 // The poll fd array
43 PollArrayWrapper pollWrapper;
44
45 // Initial capacity of the pollfd array
46 protected final int INIT_CAP = 10;
47
48 // The list of SelectableChannels serviced by this Selector
49 protected SelectionKeyImpl[] channelArray;
50
51 // In some impls the first entry of channelArray is bogus
52 protected int channelOffset = 0;
53
54 // The number of valid channels in this Selector's poll array
55 protected int totalChannels;
56
57 // True if this Selector has been closed
58 private boolean closed = false;
59
60 // Lock for close and cleanup
61 private Object closeLock = new Object();
62
63 AbstractPollSelectorImpl(SelectorProvider sp, int channels, int offset) {
64 super(sp);
65 this.totalChannels = channels;
66 this.channelOffset = offset;
67 }
68
69 public void putEventOps(SelectionKeyImpl sk, int ops) {
70 synchronized (closeLock) {
71 if (closed)
72 throw new ClosedSelectorException();
73 pollWrapper.putEventOps(sk.getIndex(), ops);
74 }
75 }
76
77 public Selector wakeup() {
78 pollWrapper.interrupt();
79 return this;
80 }
81
82 protected abstract int doSelect(long timeout) throws IOException;
83
84 protected void implClose() throws IOException {
85 synchronized (closeLock) {
86 if (closed)
87 return;
88 closed = true;
89 // Deregister channels
90 for(int i=channelOffset; i<totalChannels; i++) {
91 SelectionKeyImpl ski = channelArray[i];
92 assert(ski.getIndex() != -1);
93 ski.setIndex(-1);
94 deregister(ski);
95 SelectableChannel selch = channelArray[i].channel();
96 if (!selch.isOpen() && !selch.isRegistered())
97 ((SelChImpl)selch).kill();
98 }
99 implCloseInterrupt();
100 pollWrapper.free();
101 pollWrapper = null;
102 channelArray = null;
103 totalChannels = 0;
104 }
105 }
106
107 protected abstract void implCloseInterrupt() throws IOException;
108
109 /**
110 * Copy the information in the pollfd structs into the opss
111 * of the corresponding Channels. Add the ready keys to the
112 * ready queue.
113 */
114 protected int updateSelectedKeys() {
115 int numKeysUpdated = 0;
116 // Skip zeroth entry; it is for interrupts only
117 for (int i=channelOffset; i<totalChannels; i++) {
118 int rOps = pollWrapper.getReventOps(i);
119 if (rOps != 0) {
120 SelectionKeyImpl sk = channelArray[i];
121 pollWrapper.putReventOps(i, 0);
122 if (selectedKeys.contains(sk)) {
123 if (sk.channel.translateAndSetReadyOps(rOps, sk)) {
124 numKeysUpdated++;
125 }
126 } else {
127 sk.channel.translateAndSetReadyOps(rOps, sk);
128 if ((sk.nioReadyOps() & sk.nioInterestOps()) != 0) {
129 selectedKeys.add(sk);
130 numKeysUpdated++;
131 }
132 }
133 }
134 }
135 return numKeysUpdated;
136 }
137
138 protected void implRegister(SelectionKeyImpl ski) {
139 synchronized (closeLock) {
140 if (closed)
141 throw new ClosedSelectorException();
142
143 // Check to see if the array is large enough
144 if (channelArray.length == totalChannels) {
145 // Make a larger array
146 int newSize = pollWrapper.totalChannels * 2;
147 SelectionKeyImpl temp[] = new SelectionKeyImpl[newSize];
148 // Copy over
149 for (int i=channelOffset; i<totalChannels; i++)
150 temp[i] = channelArray[i];
151 channelArray = temp;
152 // Grow the NativeObject poll array
153 pollWrapper.grow(newSize);
154 }
155 channelArray[totalChannels] = ski;
156 ski.setIndex(totalChannels);
157 pollWrapper.addEntry(ski.channel);
158 totalChannels++;
159 keys.add(ski);
160 }
161 }
162
163 protected void implDereg(SelectionKeyImpl ski) throws IOException {
164 // Algorithm: Copy the sc from the end of the list and put it into
165 // the location of the sc to be removed (since order doesn't
166 // matter). Decrement the sc count. Update the index of the sc
167 // that is moved.
168 int i = ski.getIndex();
169 assert (i >= 0);
170 if (i != totalChannels - 1) {
171 // Copy end one over it
172 SelectionKeyImpl endChannel = channelArray[totalChannels-1];
173 channelArray[i] = endChannel;
174 endChannel.setIndex(i);
175 pollWrapper.release(i);
176 PollArrayWrapper.replaceEntry(pollWrapper, totalChannels - 1,
177 pollWrapper, i);
178 } else {
179 pollWrapper.release(i);
180 }
181 // Destroy the last one
182 channelArray[totalChannels-1] = null;
183 totalChannels--;
184 pollWrapper.totalChannels--;
185 ski.setIndex(-1);
186 // Remove the key from keys and selectedKeys
187 keys.remove(ski);
188 selectedKeys.remove(ski);
189 deregister((AbstractSelectionKey)ski);
190 SelectableChannel selch = ski.channel();
191 if (!selch.isOpen() && !selch.isRegistered())
192 ((SelChImpl)selch).kill();
193 }
194 }