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 }