1 /*
   2  * Copyright (c) 2001, 2013, 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 import sun.misc.*;
  33 
  34 
  35 /**
  36  * An abstract selector impl.
  37  */
  38 
  39 abstract class AbstractPollSelectorImpl
  40     extends SelectorImpl
  41 {
  42 
  43     // The poll fd array
  44     PollArrayWrapper pollWrapper;
  45 
  46     // Initial capacity of the pollfd array
  47     protected final int INIT_CAP = 10;
  48 
  49     // The list of SelectableChannels serviced by this Selector
  50     protected SelectionKeyImpl[] channelArray;
  51 
  52     // In some impls the first entry of channelArray is bogus
  53     protected int channelOffset = 0;
  54 
  55     // The number of valid channels in this Selector's poll array
  56     protected int totalChannels;
  57 
  58     // True if this Selector has been closed
  59     private boolean closed = false;
  60 
  61     // Lock for close and cleanup
  62     private Object closeLock = new Object();
  63 
  64     AbstractPollSelectorImpl(SelectorProvider sp, int channels, int offset) {
  65         super(sp);
  66         this.totalChannels = channels;
  67         this.channelOffset = offset;
  68     }
  69 
  70     public void putEventOps(SelectionKeyImpl sk, int ops) {
  71         synchronized (closeLock) {
  72             if (closed)
  73                 throw new ClosedSelectorException();
  74             pollWrapper.putEventOps(sk.getIndex(), ops);
  75         }
  76     }
  77 
  78     public Selector wakeup() {
  79         pollWrapper.interrupt();
  80         return this;
  81     }
  82 
  83     protected abstract int doSelect(long timeout) throws IOException;
  84 
  85     protected void implClose() throws IOException {
  86         synchronized (closeLock) {
  87             if (closed)
  88                 return;
  89             closed = true;
  90             // Deregister channels
  91             for(int i=channelOffset; i<totalChannels; i++) {
  92                 SelectionKeyImpl ski = channelArray[i];
  93                 assert(ski.getIndex() != -1);
  94                 ski.setIndex(-1);
  95                 deregister(ski);
  96                 SelectableChannel selch = channelArray[i].channel();
  97                 if (!selch.isOpen() && !selch.isRegistered())
  98                     ((SelChImpl)selch).kill();
  99             }
 100             implCloseInterrupt();
 101             pollWrapper.free();
 102             pollWrapper = null;
 103             selectedKeys = null;
 104             channelArray = null;
 105             totalChannels = 0;
 106         }
 107     }
 108 
 109     protected abstract void implCloseInterrupt() throws IOException;
 110 
 111     /**
 112      * Copy the information in the pollfd structs into the opss
 113      * of the corresponding Channels. Add the ready keys to the
 114      * ready queue.
 115      */
 116     protected int updateSelectedKeys() {
 117         int numKeysUpdated = 0;
 118         // Skip zeroth entry; it is for interrupts only
 119         for (int i=channelOffset; i<totalChannels; i++) {
 120             int rOps = pollWrapper.getReventOps(i);
 121             if (rOps != 0) {
 122                 SelectionKeyImpl sk = channelArray[i];
 123                 pollWrapper.putReventOps(i, 0);
 124                 if (selectedKeys.contains(sk)) {
 125                     if (sk.channel.translateAndSetReadyOps(rOps, sk)) {
 126                         numKeysUpdated++;
 127                     }
 128                 } else {
 129                     sk.channel.translateAndSetReadyOps(rOps, sk);
 130                     if ((sk.nioReadyOps() & sk.nioInterestOps()) != 0) {
 131                         selectedKeys.add(sk);
 132                         numKeysUpdated++;
 133                     }
 134                 }
 135             }
 136         }
 137         return numKeysUpdated;
 138     }
 139 
 140     protected void implRegister(SelectionKeyImpl ski) {
 141         synchronized (closeLock) {
 142             if (closed)
 143                 throw new ClosedSelectorException();
 144 
 145             // Check to see if the array is large enough
 146             if (channelArray.length == totalChannels) {
 147                 // Make a larger array
 148                 int newSize = pollWrapper.totalChannels * 2;
 149                 SelectionKeyImpl temp[] = new SelectionKeyImpl[newSize];
 150                 // Copy over
 151                 for (int i=channelOffset; i<totalChannels; i++)
 152                     temp[i] = channelArray[i];
 153                 channelArray = temp;
 154                 // Grow the NativeObject poll array
 155                 pollWrapper.grow(newSize);
 156             }
 157             channelArray[totalChannels] = ski;
 158             ski.setIndex(totalChannels);
 159             pollWrapper.addEntry(ski.channel);
 160             totalChannels++;
 161             keys.add(ski);
 162         }
 163     }
 164 
 165     protected void implDereg(SelectionKeyImpl ski) throws IOException {
 166         // Algorithm: Copy the sc from the end of the list and put it into
 167         // the location of the sc to be removed (since order doesn't
 168         // matter). Decrement the sc count. Update the index of the sc
 169         // that is moved.
 170         int i = ski.getIndex();
 171         assert (i >= 0);
 172         if (i != totalChannels - 1) {
 173             // Copy end one over it
 174             SelectionKeyImpl endChannel = channelArray[totalChannels-1];
 175             channelArray[i] = endChannel;
 176             endChannel.setIndex(i);
 177             pollWrapper.release(i);
 178             PollArrayWrapper.replaceEntry(pollWrapper, totalChannels - 1,
 179                                           pollWrapper, i);
 180         } else {
 181             pollWrapper.release(i);
 182         }
 183         // Destroy the last one
 184         channelArray[totalChannels-1] = null;
 185         totalChannels--;
 186         pollWrapper.totalChannels--;
 187         ski.setIndex(-1);
 188         // Remove the key from keys and selectedKeys
 189         keys.remove(ski);
 190         selectedKeys.remove(ski);
 191         deregister((AbstractSelectionKey)ski);
 192         SelectableChannel selch = ski.channel();
 193         if (!selch.isOpen() && !selch.isRegistered())
 194             ((SelChImpl)selch).kill();
 195     }
 196 }