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1 /* |
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2 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 package sun.nio.ch; |
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27 |
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28 import java.io.FileDescriptor; |
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29 import java.io.IOException; |
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30 import java.nio.ByteBuffer; |
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31 import java.nio.channels.AsynchronousCloseException; |
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32 import java.nio.channels.ByteChannel; |
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33 import java.nio.channels.ClosedChannelException; |
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34 import java.nio.channels.NotYetConnectedException; |
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35 import java.nio.channels.spi.AbstractInterruptibleChannel; |
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36 import java.util.Objects; |
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37 import java.util.concurrent.locks.ReentrantLock; |
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38 |
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39 import static java.util.concurrent.TimeUnit.NANOSECONDS; |
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40 |
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41 class UnixDomainSocketChannelImpl |
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42 extends AbstractInterruptibleChannel |
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43 implements ByteChannel |
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44 { |
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45 // Used to make native read and write calls |
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46 private static final NativeDispatcher nd = new SocketDispatcher(); |
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47 |
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48 // Our file descriptor object |
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49 private final FileDescriptor fd; |
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50 // Lock held by current reading or connecting thread |
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51 private final ReentrantLock readLock = new ReentrantLock(); |
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52 |
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53 // Lock held by current writing or connecting thread |
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54 private final ReentrantLock writeLock = new ReentrantLock(); |
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55 |
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56 // Lock for managing close state |
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57 private final Object stateLock = new Object(); |
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58 |
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59 // Channel state |
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60 private static final int ST_INUSE = 0; |
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61 private static final int ST_CLOSING = 1; |
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62 private static final int ST_CLOSED = 2; |
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63 private int state; |
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64 |
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65 // IDs of native threads doing reads and writes, for signalling |
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66 private long readerThread; |
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67 private long writerThread; |
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68 |
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69 UnixDomainSocketChannelImpl(FileDescriptor fd) |
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70 throws IOException |
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71 { |
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72 this.fd = fd; |
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73 } |
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74 |
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75 /** |
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76 * Checks that the channel is open. |
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77 * |
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78 * @throws ClosedChannelException if channel is closed (or closing) |
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79 */ |
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80 private void ensureOpen() throws ClosedChannelException { |
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81 if (!isOpen()) |
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82 throw new ClosedChannelException(); |
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83 } |
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84 |
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85 /** |
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86 * Closes the socket if there are no I/O operations in progress |
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87 */ |
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88 private boolean tryClose() throws IOException { |
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89 assert Thread.holdsLock(stateLock) && state == ST_CLOSING; |
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90 if (readerThread == 0 && writerThread == 0) { |
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91 state = ST_CLOSED; |
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92 nd.close(fd); |
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93 return true; |
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94 } else { |
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95 return false; |
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96 } |
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97 } |
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98 |
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99 /** |
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100 * Complete closure of pre-closed socket (release the file descriptor) |
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101 */ |
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102 private void tryFinishClose() { |
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103 try { |
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104 tryClose(); |
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105 } catch (IOException ignore) { } |
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106 } |
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107 |
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108 /** |
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109 * Marks the beginning of a read operation |
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110 * |
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111 * @throws ClosedChannelException if the channel is closed |
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112 * @throws NotYetConnectedException if the channel is not yet connected |
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113 */ |
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114 private void beginRead() throws ClosedChannelException { |
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115 // set hook for Thread.interrupt |
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116 begin(); |
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117 synchronized (stateLock) { |
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118 ensureOpen(); |
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119 readerThread = NativeThread.current(); |
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120 } |
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121 } |
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122 |
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123 /** |
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124 * Marks the end of a read operation that may have blocked. |
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125 * |
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126 * @throws AsynchronousCloseException if the channel was closed due to this |
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127 * thread being interrupted on a blocking read operation. |
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128 */ |
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129 private void endRead(boolean completed) |
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130 throws AsynchronousCloseException |
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131 { |
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132 synchronized (stateLock) { |
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133 readerThread = 0; |
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134 if (state == ST_CLOSING) { |
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135 tryFinishClose(); |
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136 } |
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137 } |
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138 end(completed); |
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139 } |
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140 |
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141 @Override |
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142 public int read(ByteBuffer buf) throws IOException { |
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143 Objects.requireNonNull(buf); |
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144 |
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145 readLock.lock(); |
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146 try { |
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147 int n = 0; |
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148 try { |
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149 beginRead(); |
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150 n = IOUtil.read(fd, buf, -1, nd); |
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151 while (IOStatus.okayToRetry(n) && isOpen()) { |
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152 park(Net.POLLIN, 0L); |
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153 n = IOUtil.read(fd, buf, -1, nd); |
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154 } |
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155 } finally { |
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156 endRead(n > 0); |
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157 } |
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158 return n; |
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159 } finally { |
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160 readLock.unlock(); |
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161 } |
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162 } |
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163 |
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164 /** |
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165 * Marks the beginning of a write operation that might block. |
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166 * |
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167 * @throws ClosedChannelException if the channel is closed |
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168 * @throws NotYetConnectedException if the channel is not yet connected |
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169 */ |
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170 private void beginWrite() throws ClosedChannelException { |
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171 begin(); |
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172 synchronized (stateLock) { |
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173 // set hook for Thread.interrupt |
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174 ensureOpen(); |
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175 writerThread = NativeThread.current(); |
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176 } |
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177 } |
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178 |
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179 /** |
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180 * Marks the end of a write operation that may have blocked. |
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181 * |
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182 * @throws AsynchronousCloseException if the channel was closed due to this |
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183 * thread being interrupted on a blocking write operation. |
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184 */ |
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185 private void endWrite(boolean completed) |
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186 throws AsynchronousCloseException |
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187 { |
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188 synchronized (stateLock) { |
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189 writerThread = 0; |
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190 if (state == ST_CLOSING) { |
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191 tryFinishClose(); |
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192 } |
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193 } |
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194 end(completed); |
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195 } |
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196 |
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197 void park(int event, long nanos) throws IOException { |
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198 long millis; |
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199 if (nanos <= 0) { |
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200 millis = -1; |
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201 } else { |
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202 millis = NANOSECONDS.toMillis(nanos); |
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203 } |
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204 Net.poll(fd, event, millis); |
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205 } |
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206 |
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207 @Override |
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208 public int write(ByteBuffer buf) throws IOException { |
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209 Objects.requireNonNull(buf); |
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210 |
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211 writeLock.lock(); |
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212 try { |
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213 int n = 0; |
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214 try { |
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215 beginWrite(); |
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216 n = IOUtil.write(fd, buf, -1, nd); |
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217 while (IOStatus.okayToRetry(n) && isOpen()) { |
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218 park(Net.POLLOUT, 0L); |
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219 n = IOUtil.write(fd, buf, -1, nd); |
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220 } |
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221 } finally { |
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222 endWrite(n > 0); |
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223 } |
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224 return n; |
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225 } finally { |
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226 writeLock.unlock(); |
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227 } |
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228 } |
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229 |
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230 /** |
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231 * Closes this channel |
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232 * |
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233 * If there is an I/O operation in progress then the socket is pre-closed |
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234 * and the I/O threads signalled, in which case the final close is deferred |
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235 * until all I/O operations complete. |
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236 */ |
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237 @Override |
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238 protected void implCloseChannel() throws IOException { |
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239 synchronized (stateLock) { |
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240 assert state == ST_INUSE; |
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241 state = ST_CLOSING; |
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242 if (!tryClose()) { |
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243 long reader = readerThread; |
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244 long writer = writerThread; |
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245 if (reader != 0 || writer != 0) { |
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246 nd.preClose(fd); |
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247 if (reader != 0) |
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248 NativeThread.signal(reader); |
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249 if (writer != 0) |
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250 NativeThread.signal(writer); |
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251 } |
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252 } |
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253 } |
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254 } |
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255 |
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256 @Override |
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257 public String toString() { |
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258 StringBuilder sb = new StringBuilder(); |
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259 sb.append(this.getClass().getSuperclass().getName()); |
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260 sb.append('['); |
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261 if (!isOpen()) |
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262 sb.append("closed"); |
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263 sb.append(']'); |
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264 return sb.toString(); |
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265 } |
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266 } |