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 }