/*
* Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package sun.nio.ch;
import java.io.IOException;
import jdk.internal.misc.Unsafe;
/**
* Provides access to the BSD kqueue facility.
*/
class KQueue {
private KQueue() { }
private static final Unsafe unsafe = Unsafe.getUnsafe();
/**
* struct kevent {
* uintptr_t ident; // identifier for this event, usually the fd
* int16_t filter; // filter for event
* uint16_t flags; // general flags
* uint32_t fflags; // filter-specific flags
* intptr_t data; // filter-specific data
* void *udata; // opaque user data identifier
* };
*/
private static final int SIZEOF_KQUEUEEVENT = keventSize();
private static final int OFFSET_IDENT = identOffset();
private static final int OFFSET_FILTER = filterOffset();
private static final int OFFSET_FLAGS = flagsOffset();
// filters
static final int EVFILT_READ = -1;
static final int EVFILT_WRITE = -2;
// flags
static final int EV_ADD = 0x0001;
static final int EV_DELETE = 0x0002;
static final int EV_ONESHOT = 0x0010;
static final int EV_CLEAR = 0x0020;
/**
* Allocates a poll array to handle up to {@code count} events.
*/
static long allocatePollArray(int count) {
return unsafe.allocateMemory(count * SIZEOF_KQUEUEEVENT);
}
/**
* Free a poll array
*/
static void freePollArray(long address) {
unsafe.freeMemory(address);
}
/**
* Returns kevent[i].
*/
static long getEvent(long address, int i) {
return address + (SIZEOF_KQUEUEEVENT*i);
}
/**
* Returns the file descriptor from a kevent (assuming it is in the ident field)
*/
static int getDescriptor(long address) {
return unsafe.getInt(address + OFFSET_IDENT);
}
static short getFilter(long address) {
return unsafe.getShort(address + OFFSET_FILTER);
}
static short getFlags(long address) {
return unsafe.getShort(address + OFFSET_FLAGS);
}
// -- Native methods --
private static native int keventSize();
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