/*
* Copyright (c) 2001, 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 java.nio.channels.ClosedSelectorException;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.spi.SelectorProvider;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import java.util.function.Consumer;
import static sun.nio.ch.DevPollArrayWrapper.NUM_POLLFDS;
import static sun.nio.ch.DevPollArrayWrapper.POLLREMOVE;
/**
* Solaris /dev/poll based Selector implementation
*/
class DevPollSelectorImpl
extends SelectorImpl
{
// provides access to /dev/poll driver
private final DevPollArrayWrapper pollWrapper;
// file descriptors used for interrupt
private final int fd0;
private final int fd1;
// maps file descriptor to selection key, synchronize on selector
private final Map<Integer, SelectionKeyImpl> fdToKey = new HashMap<>();
// pending new registrations/updates, queued by setEventOps
private final Object updateLock = new Object();
private final Deque<SelectionKeyImpl> updateKeys = new ArrayDeque<>();
// interrupt triggering and clearing
private final Object interruptLock = new Object();
private boolean interruptTriggered;
DevPollSelectorImpl(SelectorProvider sp) throws IOException {
super(sp);
this.pollWrapper = new DevPollArrayWrapper();
try {
long fds = IOUtil.makePipe(false);
this.fd0 = (int) (fds >>> 32);
this.fd1 = (int) fds;
} catch (IOException ioe) {
pollWrapper.close();
throw ioe;
}
// register one end of the socket pair for wakeups
pollWrapper.register(fd0, Net.POLLIN);
}
private void ensureOpen() {
if (!isOpen())
throw new ClosedSelectorException();
}
@Override
protected int doSelect(Consumer<SelectionKey> action, long timeout)
throws IOException
{
assert Thread.holdsLock(this);
long to = timeout;
boolean blocking = (to != 0);
boolean timedPoll = (to > 0);
int numEntries;
processUpdateQueue();
processDeregisterQueue();
try {
begin(blocking);
do {
long startTime = timedPoll ? System.nanoTime() : 0;
numEntries = pollWrapper.poll(to);
if (numEntries == IOStatus.INTERRUPTED && timedPoll) {
// timed poll interrupted so need to adjust timeout
long adjust = System.nanoTime() - startTime;
to -= TimeUnit.MILLISECONDS.convert(adjust, TimeUnit.NANOSECONDS);
if (to <= 0) {
// timeout expired so no retry
numEntries = 0;
}
}
} while (numEntries == IOStatus.INTERRUPTED);
assert IOStatus.check(numEntries);
} finally {
end(blocking);
}
processDeregisterQueue();
return processEvents(numEntries, action);
}
/**
* Process changes to the interest ops.
*/
private void processUpdateQueue() throws IOException {
assert Thread.holdsLock(this);
synchronized (updateLock) {
SelectionKeyImpl ski;
// Translate the queued updates to changes to the set of monitored
// file descriptors. The changes are written to the /dev/poll driver
// in bulk.
int index = 0;
while ((ski = updateKeys.pollFirst()) != null) {
if (ski.isValid()) {
int fd = ski.getFDVal();
// add to fdToKey if needed
SelectionKeyImpl previous = fdToKey.putIfAbsent(fd, ski);
assert (previous == null) || (previous == ski);
int newEvents = ski.translateInterestOps();
int registeredEvents = ski.registeredEvents();
if (newEvents != registeredEvents) {
if (registeredEvents != 0)
pollWrapper.putPollFD(index++, fd, POLLREMOVE);
if (newEvents != 0)
pollWrapper.putPollFD(index++, fd, (short)newEvents);
ski.registeredEvents(newEvents);
// write to /dev/poll
if (index > (NUM_POLLFDS-2)) {
pollWrapper.registerMultiple(index);
index = 0;
}
}
}
}
// write any remaining changes
if (index > 0)
pollWrapper.registerMultiple(index);
}
}
/**
* Process the polled events.
* If the interrupt fd has been selected, drain it and clear the interrupt.
*/
private int processEvents(int numEntries, Consumer<SelectionKey> action)
throws IOException
{
assert Thread.holdsLock(this);
boolean interrupted = false;
int numKeysUpdated = 0;
for (int i=0; i<numEntries; i++) {
int fd = pollWrapper.getDescriptor(i);
if (fd == fd0) {
interrupted = true;
} else {
SelectionKeyImpl ski = fdToKey.get(fd);
if (ski != null) {
int rOps = pollWrapper.getReventOps(i);
numKeysUpdated += processReadyEvents(rOps, ski, action);
}
}
}
if (interrupted) {
clearInterrupt();
}
return numKeysUpdated;
}
@Override
protected void implClose() throws IOException {
assert !isOpen();
assert Thread.holdsLock(this);
// prevent further wakeup
synchronized (interruptLock) {
interruptTriggered = true;
}
pollWrapper.close();
FileDispatcherImpl.closeIntFD(fd0);
FileDispatcherImpl.closeIntFD(fd1);
}
@Override
protected void implDereg(SelectionKeyImpl ski) throws IOException {
assert !ski.isValid();
assert Thread.holdsLock(this);
int fd = ski.getFDVal();
if (fdToKey.remove(fd) != null) {
if (ski.registeredEvents() != 0) {
pollWrapper.register(fd, POLLREMOVE);
ski.registeredEvents(0);
/**代码未完, 请加载全部代码(NowJava.com).**/