rev 12972 : 8140606: Update library code to use internal Unsafe
Reviewed-by: duke

   1 /*
   2  * Copyright (c) 2012, 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 sun.misc.Unsafe;
  30 
  31 /**
  32  * Provides access to the BSD kqueue facility.
  33  */
  34 
  35 class KQueue {
  36     private KQueue() { }
  37 
  38     private static final Unsafe unsafe = Unsafe.getUnsafe();
  39 
  40     /**
  41      * struct kevent {
  42      *        uintptr_t       ident;          // identifier for this event, usually the fd
  43      *        int16_t         filter;         // filter for event
  44      *        uint16_t        flags;          // general flags
  45      *        uint32_t        fflags;         // filter-specific flags
  46      *        intptr_t        data;           // filter-specific data
  47      *        void            *udata;         // opaque user data identifier
  48      * };
  49      */
  50     private static final int SIZEOF_KQUEUEEVENT    = keventSize();
  51     private static final int OFFSET_IDENT          = identOffset();
  52     private static final int OFFSET_FILTER         = filterOffset();
  53     private static final int OFFSET_FLAGS          = flagsOffset();
  54 
  55     // filters
  56     static final int EVFILT_READ  = -1;
  57     static final int EVFILT_WRITE = -2;
  58 
  59     // flags
  60     static final int EV_ADD     = 0x0001;
  61     static final int EV_ONESHOT = 0x0010;
  62     static final int EV_CLEAR   = 0x0020;
  63 
  64     /**
  65      * Allocates a poll array to handle up to {@code count} events.
  66      */
  67     static long allocatePollArray(int count) {
  68         return unsafe.allocateMemory(count * SIZEOF_KQUEUEEVENT);
  69     }
  70 
  71     /**
  72      * Free a poll array
  73      */
  74     static void freePollArray(long address) {
  75         unsafe.freeMemory(address);
  76     }
  77 
  78     /**
  79      * Returns kevent[i].
  80      */
  81     static long getEvent(long address, int i) {
  82         return address + (SIZEOF_KQUEUEEVENT*i);
  83     }
  84 
  85     /**
  86      * Returns the file descriptor from a kevent (assuming to be in ident field)
  87      */
  88     static int getDescriptor(long address) {
  89         return unsafe.getInt(address + OFFSET_IDENT);
  90     }
  91 
  92     static int getFilter(long address) {
  93         return unsafe.getShort(address + OFFSET_FILTER);
  94     }
  95 
  96     static int getFlags(long address) {
  97         return unsafe.getShort(address + OFFSET_FLAGS);
  98     }
  99 
 100     // -- Native methods --
 101 
 102     private static native int keventSize();
 103 
 104     private static native int identOffset();
 105 
 106     private static native int filterOffset();
 107 
 108     private static native int flagsOffset();
 109 
 110     static native int kqueue() throws IOException;
 111 
 112     static native int keventRegister(int kqpfd, int fd, int filter, int flags);
 113 
 114     static native int keventPoll(int kqpfd, long pollAddress, int nevents)
 115         throws IOException;
 116 
 117     static {
 118         IOUtil.load();
 119     }
 120 }
--- EOF ---