/*
* 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
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*/
package sun.nio.ch;
import java.nio.channels.spi.AsynchronousChannelProvider;
import java.util.concurrent.RejectedExecutionException;
import java.io.IOException;
import jdk.internal.misc.Unsafe;
/**
* Provides an AsynchronousChannelGroup implementation based on the Solaris 10
* event port framework and also provides direct access to that framework.
*/
class SolarisEventPort
extends Port
{
private static final Unsafe unsafe = Unsafe.getUnsafe();
private static final int addressSize = unsafe.addressSize();
private static int dependsArch(int value32, int value64) {
return (addressSize == 4) ? value32 : value64;
}
/*
* typedef struct port_event {
* int portev_events;
* ushort_t portev_source;
* ushort_t portev_pad;
* uintptr_t portev_object;
* void *portev_user;
* } port_event_t;
*/
static final int SIZEOF_PORT_EVENT = dependsArch(16, 24);
static final int OFFSETOF_EVENTS = 0;
static final int OFFSETOF_SOURCE = 4;
static final int OFFSETOF_OBJECT = 8;
// port sources
static final short PORT_SOURCE_USER = 3;
static final short PORT_SOURCE_FD = 4;
// file descriptor to event port.
private final int port;
// true when port is closed
private boolean closed;
SolarisEventPort(AsynchronousChannelProvider provider, ThreadPool pool)
throws IOException
{
super(provider, pool);
// create event port
this.port = port_create();
}
SolarisEventPort start() {
startThreads(new EventHandlerTask());
return this;
}
// releass resources
private void implClose() {
synchronized (this) {
if (closed)
return;
closed = true;
}
port_close(port);
}
private void wakeup() {
try {
port_send(port, 0);
} catch (IOException x) {
throw new AssertionError(x);
}
}
@Override
void executeOnHandlerTask(Runnable task) {
synchronized (this) {
if (closed)
throw new RejectedExecutionException();
offerTask(task);
wakeup();
}
}
@Override
void shutdownHandlerTasks() {
/*
* If no tasks are running then just release resources; otherwise
* write to the one end of the socketpair to wakeup any polling threads..
*/
int nThreads = threadCount();
if (nThreads == 0) {
implClose();
} else {
// send user event to wakeup each thread
while (nThreads-- > 0) {
try {
port_send(port, 0);
} catch (IOException x) {
throw new AssertionError(x);
}
}
}
}
@Override
void startPoll(int fd, int events) {
// (re-)associate file descriptor
// no need to translate events
try {
port_associate(port, PORT_SOURCE_FD, fd, events);
} catch (IOException x) {
throw new AssertionError(); // should not happen
}
}
/*
* Task to read a single event from the port and dispatch it to the
* channel's onEvent handler.
*/
private class EventHandlerTask implements Runnable {
public void run() {
Invoker.GroupAndInvokeCount myGroupAndInvokeCount =
Invoker.getGroupAndInvokeCount();
final boolean isPooledThread = (myGroupAndInvokeCount != null);
boolean replaceMe = false;
long address = unsafe.allocateMemory(SIZEOF_PORT_EVENT);
try {
for (;;) {
// reset invoke count
if (isPooledThread)
myGroupAndInvokeCount.resetInvokeCount();
// wait for I/O completion event
// A error here is fatal (thread will not be replaced)
replaceMe = false;
try {
int n;
do {
n = port_get(port, address);
} while (n == IOStatus.INTERRUPTED);
} catch (IOException x) {
x.printStackTrace();
return;
}
// event source
short source = unsafe.getShort(address + OFFSETOF_SOURCE);
if (source != PORT_SOURCE_FD) {
// user event is trigger to invoke task or shutdown
if (source == PORT_SOURCE_USER) {
Runnable task = pollTask();
if (task == null) {
// shutdown request
return;
}
// run task (may throw error/exception)
replaceMe = true;
task.run();
}
// ignore
continue;
}
// pe->portev_object is file descriptor
int fd = (int)unsafe.getAddress(address + OFFSETOF_OBJECT);
// pe->portev_events
int events = unsafe.getInt(address + OFFSETOF_EVENTS);
// lookup channel
PollableChannel ch;
fdToChannelLock.readLock().lock();
try {
ch = fdToChannel.get(fd);
} finally {
fdToChannelLock.readLock().unlock();
}
// notify channel
if (ch != null) {
replaceMe = true;
// no need to translate events
ch.onEvent(events, isPooledThread);
}
}
} finally {
// free per-thread resources
unsafe.freeMemory(address);
// last task to exit when shutdown release resources
int remaining = threadExit(this, replaceMe);
if (remaining == 0 && isShutdown())
implClose();
}
}
}
/**
* Creates an event port
*/
static native int port_create() throws IOException;
/**
* Associates specific events of a given object with a port
*/
static native boolean port_associate(int port, int source, long object, int events)
throws IOException;
/**
* Removes the association of an object with a port.
*/
static native boolean port_dissociate(int port, int source, long object)
throws IOException;
/**
* Retrieves a single event from a port
*/
static native int port_get(int port, long address) throws IOException;
/**
* Retrieves at most {@code max} events from a port.
*/
static native int port_getn(int port, long address, int max, long timeout)
throws IOException;
/**
* Sends a user-defined eventto a specified port.
*/
static native void port_send(int port, int events) throws IOException;
/**
* Closes a port.
*/
static native void port_close(int port);
static {
IOUtil.load();
}
}