mirror of git://gcc.gnu.org/git/gcc.git
398 lines
12 KiB
Java
398 lines
12 KiB
Java
/* SelectorImpl.java --
|
|
Copyright (C) 2002, 2003, 2004, 2006 Free Software Foundation, Inc.
|
|
|
|
This file is part of GNU Classpath.
|
|
|
|
GNU Classpath is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2, or (at your option)
|
|
any later version.
|
|
|
|
GNU Classpath 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 for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with GNU Classpath; see the file COPYING. If not, write to the
|
|
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
|
02110-1301 USA.
|
|
|
|
Linking this library statically or dynamically with other modules is
|
|
making a combined work based on this library. Thus, the terms and
|
|
conditions of the GNU General Public License cover the whole
|
|
combination.
|
|
|
|
As a special exception, the copyright holders of this library give you
|
|
permission to link this library with independent modules to produce an
|
|
executable, regardless of the license terms of these independent
|
|
modules, and to copy and distribute the resulting executable under
|
|
terms of your choice, provided that you also meet, for each linked
|
|
independent module, the terms and conditions of the license of that
|
|
module. An independent module is a module which is not derived from
|
|
or based on this library. If you modify this library, you may extend
|
|
this exception to your version of the library, but you are not
|
|
obligated to do so. If you do not wish to do so, delete this
|
|
exception statement from your version. */
|
|
|
|
|
|
package gnu.java.nio;
|
|
|
|
import java.io.IOException;
|
|
import java.nio.channels.ClosedSelectorException;
|
|
import java.nio.channels.SelectableChannel;
|
|
import java.nio.channels.SelectionKey;
|
|
import java.nio.channels.Selector;
|
|
import java.nio.channels.SocketChannel;
|
|
import java.nio.channels.spi.AbstractSelectableChannel;
|
|
import java.nio.channels.spi.AbstractSelector;
|
|
import java.nio.channels.spi.SelectorProvider;
|
|
import java.util.Collections;
|
|
import java.util.HashSet;
|
|
import java.util.Iterator;
|
|
import java.util.Set;
|
|
|
|
public class SelectorImpl extends AbstractSelector
|
|
{
|
|
private Set<SelectionKey> keys;
|
|
private Set<SelectionKey> selected;
|
|
|
|
/**
|
|
* A dummy object whose monitor regulates access to both our
|
|
* selectThread and unhandledWakeup fields.
|
|
*/
|
|
private Object selectThreadMutex = new Object ();
|
|
|
|
/**
|
|
* Any thread that's currently blocked in a select operation.
|
|
*/
|
|
private Thread selectThread;
|
|
|
|
/**
|
|
* Indicates whether we have an unhandled wakeup call. This can
|
|
* be due to either wakeup() triggering a thread interruption while
|
|
* a thread was blocked in a select operation (in which case we need
|
|
* to reset this thread's interrupt status after interrupting the
|
|
* select), or else that no thread was on a select operation at the
|
|
* time that wakeup() was called, in which case the following select()
|
|
* operation should return immediately with nothing selected.
|
|
*/
|
|
private boolean unhandledWakeup;
|
|
|
|
public SelectorImpl (SelectorProvider provider)
|
|
{
|
|
super (provider);
|
|
|
|
keys = new HashSet<SelectionKey> ();
|
|
selected = new HashSet<SelectionKey> ();
|
|
}
|
|
|
|
protected void finalize() throws Throwable
|
|
{
|
|
close();
|
|
}
|
|
|
|
protected final void implCloseSelector()
|
|
throws IOException
|
|
{
|
|
// Cancel any pending select operation.
|
|
wakeup();
|
|
|
|
synchronized (keys)
|
|
{
|
|
synchronized (selected)
|
|
{
|
|
synchronized (cancelledKeys ())
|
|
{
|
|
// FIXME: Release resources here.
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
public final Set<SelectionKey> keys()
|
|
{
|
|
if (!isOpen())
|
|
throw new ClosedSelectorException();
|
|
|
|
return Collections.unmodifiableSet (keys);
|
|
}
|
|
|
|
public final int selectNow()
|
|
throws IOException
|
|
{
|
|
// FIXME: We're simulating an immediate select
|
|
// via a select with a timeout of one millisecond.
|
|
return select (1);
|
|
}
|
|
|
|
public final int select()
|
|
throws IOException
|
|
{
|
|
return select (0);
|
|
}
|
|
|
|
private final int[] getFDsAsArray (int ops)
|
|
{
|
|
int[] result;
|
|
int counter = 0;
|
|
Iterator<SelectionKey> it = keys.iterator ();
|
|
|
|
// Count the number of file descriptors needed
|
|
while (it.hasNext ())
|
|
{
|
|
SelectionKeyImpl key = (SelectionKeyImpl) it.next ();
|
|
|
|
if ((key.interestOps () & ops) != 0)
|
|
{
|
|
counter++;
|
|
}
|
|
}
|
|
|
|
result = new int[counter];
|
|
|
|
counter = 0;
|
|
it = keys.iterator ();
|
|
|
|
// Fill the array with the file descriptors
|
|
while (it.hasNext ())
|
|
{
|
|
SelectionKeyImpl key = (SelectionKeyImpl) it.next ();
|
|
|
|
if ((key.interestOps () & ops) != 0)
|
|
{
|
|
result[counter] = key.getNativeFD();
|
|
counter++;
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
public synchronized int select (long timeout)
|
|
throws IOException
|
|
{
|
|
if (!isOpen())
|
|
throw new ClosedSelectorException();
|
|
|
|
synchronized (keys)
|
|
{
|
|
synchronized (selected)
|
|
{
|
|
deregisterCancelledKeys();
|
|
|
|
// Set only keys with the needed interest ops into the arrays.
|
|
int[] read = getFDsAsArray (SelectionKey.OP_READ
|
|
| SelectionKey.OP_ACCEPT);
|
|
int[] write = getFDsAsArray (SelectionKey.OP_WRITE
|
|
| SelectionKey.OP_CONNECT);
|
|
|
|
// FIXME: We dont need to check this yet
|
|
int[] except = new int [0];
|
|
|
|
// Test to see if we've got an unhandled wakeup call,
|
|
// in which case we return immediately. Otherwise,
|
|
// remember our current thread and jump into the select.
|
|
// The monitor for dummy object selectThreadMutex regulates
|
|
// access to these fields.
|
|
|
|
// FIXME: Not sure from the spec at what point we should
|
|
// return "immediately". Is it here or immediately upon
|
|
// entry to this function?
|
|
|
|
// NOTE: There's a possibility of another thread calling
|
|
// wakeup() immediately after our thread releases
|
|
// selectThreadMutex's monitor here, in which case we'll
|
|
// do the select anyway. Since calls to wakeup() and select()
|
|
// among different threads happen in non-deterministic order,
|
|
// I don't think this is an issue.
|
|
synchronized (selectThreadMutex)
|
|
{
|
|
if (unhandledWakeup)
|
|
{
|
|
unhandledWakeup = false;
|
|
return 0;
|
|
}
|
|
else
|
|
{
|
|
selectThread = Thread.currentThread ();
|
|
}
|
|
}
|
|
|
|
// Call the native select() on all file descriptors.
|
|
int result = 0;
|
|
try
|
|
{
|
|
begin();
|
|
result = VMSelector.select (read, write, except, timeout);
|
|
}
|
|
finally
|
|
{
|
|
end();
|
|
}
|
|
|
|
// If our unhandled wakeup flag is set at this point,
|
|
// reset our thread's interrupt flag because we were
|
|
// awakened by wakeup() instead of an external thread
|
|
// interruption.
|
|
//
|
|
// NOTE: If we were blocked in a select() and one thread
|
|
// called Thread.interrupt() on the blocked thread followed
|
|
// by another thread calling Selector.wakeup(), then race
|
|
// conditions could make it so that the thread's interrupt
|
|
// flag is reset even though the Thread.interrupt() call
|
|
// "was there first". I don't think we need to care about
|
|
// this scenario.
|
|
synchronized (selectThreadMutex)
|
|
{
|
|
if (unhandledWakeup)
|
|
{
|
|
unhandledWakeup = false;
|
|
Thread.interrupted ();
|
|
}
|
|
selectThread = null;
|
|
}
|
|
|
|
Iterator<SelectionKey> it = keys.iterator ();
|
|
|
|
while (it.hasNext ())
|
|
{
|
|
int ops = 0;
|
|
SelectionKeyImpl key = (SelectionKeyImpl) it.next ();
|
|
|
|
// If key is already selected retrieve old ready ops.
|
|
if (selected.contains (key))
|
|
{
|
|
ops = key.readyOps ();
|
|
}
|
|
|
|
// Set new ready read/accept ops
|
|
for (int i = 0; i < read.length; i++)
|
|
{
|
|
if (key.getNativeFD() == read[i])
|
|
{
|
|
if (key.channel () instanceof ServerSocketChannelImpl)
|
|
{
|
|
ops = ops | SelectionKey.OP_ACCEPT;
|
|
}
|
|
else
|
|
{
|
|
ops = ops | SelectionKey.OP_READ;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Set new ready write ops
|
|
for (int i = 0; i < write.length; i++)
|
|
{
|
|
if (key.getNativeFD() == write[i])
|
|
{
|
|
if (key.channel() instanceof SocketChannel)
|
|
{
|
|
if (((SocketChannel) key.channel ()).isConnected ())
|
|
ops = ops | SelectionKey.OP_WRITE;
|
|
else
|
|
ops = ops | SelectionKey.OP_CONNECT;
|
|
}
|
|
else
|
|
ops = ops | SelectionKey.OP_WRITE;
|
|
}
|
|
}
|
|
|
|
// FIXME: We dont handle exceptional file descriptors yet.
|
|
|
|
// If key is not yet selected add it.
|
|
if (!selected.contains (key))
|
|
{
|
|
selected.add (key);
|
|
}
|
|
|
|
// Set new ready ops
|
|
key.readyOps (key.interestOps () & ops);
|
|
}
|
|
deregisterCancelledKeys();
|
|
|
|
return result;
|
|
}
|
|
}
|
|
}
|
|
|
|
public final Set<SelectionKey> selectedKeys()
|
|
{
|
|
if (!isOpen())
|
|
throw new ClosedSelectorException();
|
|
|
|
return selected;
|
|
}
|
|
|
|
public final Selector wakeup()
|
|
{
|
|
// IMPLEMENTATION NOTE: Whereas the specification says that
|
|
// thread interruption should trigger a call to wakeup, we
|
|
// do the reverse under the covers: wakeup triggers a thread
|
|
// interrupt followed by a subsequent reset of the thread's
|
|
// interrupt status within select().
|
|
|
|
// First, acquire the monitor of the object regulating
|
|
// access to our selectThread and unhandledWakeup fields.
|
|
synchronized (selectThreadMutex)
|
|
{
|
|
unhandledWakeup = true;
|
|
|
|
// Interrupt any thread which is currently blocked in
|
|
// a select operation.
|
|
if (selectThread != null)
|
|
selectThread.interrupt ();
|
|
}
|
|
|
|
return this;
|
|
}
|
|
|
|
private final void deregisterCancelledKeys()
|
|
{
|
|
Set<SelectionKey> ckeys = cancelledKeys ();
|
|
synchronized (ckeys)
|
|
{
|
|
Iterator<SelectionKey> it = ckeys.iterator();
|
|
|
|
while (it.hasNext ())
|
|
{
|
|
keys.remove ((SelectionKeyImpl) it.next ());
|
|
it.remove ();
|
|
}
|
|
}
|
|
}
|
|
|
|
protected SelectionKey register (SelectableChannel ch, int ops, Object att)
|
|
{
|
|
return register ((AbstractSelectableChannel) ch, ops, att);
|
|
}
|
|
|
|
protected final SelectionKey register (AbstractSelectableChannel ch, int ops,
|
|
Object att)
|
|
{
|
|
SelectionKeyImpl result;
|
|
|
|
if (ch instanceof SocketChannelImpl)
|
|
result = new SocketChannelSelectionKey (ch, this);
|
|
else if (ch instanceof DatagramChannelImpl)
|
|
result = new DatagramChannelSelectionKey (ch, this);
|
|
else if (ch instanceof ServerSocketChannelImpl)
|
|
result = new ServerSocketChannelSelectionKey (ch, this);
|
|
else if (ch instanceof gnu.java.nio.SocketChannelImpl)
|
|
result = new gnu.java.nio.SocketChannelSelectionKeyImpl((gnu.java.nio.SocketChannelImpl)ch, this);
|
|
else
|
|
throw new InternalError ("No known channel type");
|
|
|
|
synchronized (keys)
|
|
{
|
|
keys.add (result);
|
|
|
|
result.interestOps (ops);
|
|
result.attach (att);
|
|
}
|
|
|
|
return result;
|
|
}
|
|
}
|