/*
 * Copyright (c) 2008, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.nio.ch;

import java.io.IOException;
import jdk.internal.misc.Unsafe;

Provides access to the Linux epoll facility.
/** * Provides access to the Linux epoll facility. */
class EPoll { private EPoll() { } private static final Unsafe unsafe = Unsafe.getUnsafe();
typedef union epoll_data { void *ptr; int fd; __uint32_t u32; __uint64_t u64; } epoll_data_t; struct epoll_event { __uint32_t events; epoll_data_t data; }
/** * typedef union epoll_data { * void *ptr; * int fd; * __uint32_t u32; * __uint64_t u64; * } epoll_data_t; * * struct epoll_event { * __uint32_t events; * epoll_data_t data; * } */
private static final int SIZEOF_EPOLLEVENT = eventSize(); private static final int OFFSETOF_EVENTS = eventsOffset(); private static final int OFFSETOF_FD = dataOffset(); // opcodes static final int EPOLL_CTL_ADD = 1; static final int EPOLL_CTL_DEL = 2; static final int EPOLL_CTL_MOD = 3; // events static final int EPOLLIN = 0x1; static final int EPOLLOUT = 0x4; // flags static final int EPOLLONESHOT = (1 << 30);
Allocates a poll array to handle up to count events.
/** * Allocates a poll array to handle up to {@code count} events. */
static long allocatePollArray(int count) { return unsafe.allocateMemory(count * SIZEOF_EPOLLEVENT); }
Free a poll array
/** * Free a poll array */
static void freePollArray(long address) { unsafe.freeMemory(address); }
Returns event[i];
/** * Returns event[i]; */
static long getEvent(long address, int i) { return address + (SIZEOF_EPOLLEVENT*i); }
Returns event->data.fd
/** * Returns event->data.fd */
static int getDescriptor(long eventAddress) { return unsafe.getInt(eventAddress + OFFSETOF_FD); }
Returns event->events
/** * Returns event->events */
static int getEvents(long eventAddress) { return unsafe.getInt(eventAddress + OFFSETOF_EVENTS); } // -- Native methods -- private static native int eventSize(); private static native int eventsOffset(); private static native int dataOffset(); static native int create() throws IOException; static native int ctl(int epfd, int opcode, int fd, int events); static native int wait(int epfd, long pollAddress, int numfds, int timeout) throws IOException; static { IOUtil.load(); } }