src/java.base/unix/classes/sun/nio/ch/SourceChannelImpl.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2000, 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.FileDescriptor;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.AsynchronousCloseException;
 import java.nio.channels.ClosedChannelException;
 import java.nio.channels.NotYetConnectedException;
 import java.nio.channels.Pipe;
 import java.nio.channels.SelectionKey;
 import java.nio.channels.spi.SelectorProvider;
 import java.util.Objects;
 import java.util.concurrent.locks.ReentrantLock;

 class SourceChannelImpl
     extends Pipe.SourceChannel
     implements SelChImpl
 {
     // Used to make native read and write calls
     private static final NativeDispatcher nd = new FileDispatcherImpl();

     // The file descriptor associated with this channel
     private final FileDescriptor fd;
     private final int fdVal;

     // Lock held by current reading thread
     private final ReentrantLock readLock = new ReentrantLock();

     // Lock held by any thread that modifies the state fields declared below
     // DO NOT invoke a blocking I/O operation while holding this lock!
     private final Object stateLock = new Object();

     // -- The following fields are protected by stateLock

     // Channel state
     private static final int ST_INUSE = 0;
     private static final int ST_CLOSING = 1;
     private static final int ST_KILLPENDING = 2;
     private static final int ST_KILLED = 3;
     private int state;

     // ID of native thread doing read, for signalling
     private long thread;

     // -- End of fields protected by stateLock


     public FileDescriptor getFD() {
         return fd;
     }

     public int getFDVal() {
         return fdVal;
     }

     SourceChannelImpl(SelectorProvider sp, FileDescriptor fd) {
         super(sp);
         this.fd = fd;
         this.fdVal = IOUtil.fdVal(fd);
     }

     /**
      * Invoked by implCloseChannel to close the channel.
      */
     @Override
     protected void implCloseSelectableChannel() throws IOException {
         assert !isOpen();

         boolean interrupted = false;
         boolean blocking;

         // set state to ST_CLOSING
         synchronized (stateLock) {
             assert state < ST_CLOSING;
             state = ST_CLOSING;
             blocking = isBlocking();
         }

         // wait for any outstanding read to complete
         if (blocking) {
             synchronized (stateLock) {
                 assert state == ST_CLOSING;
                 long th = thread;
                 if (th != 0) {
                     nd.preClose(fd);
                     NativeThread.signal(th);

                     // wait for read operation to end
                     while (thread != 0) {
                         try {
                             stateLock.wait();
                         } catch (InterruptedException e) {
                             interrupted = true;
                         }
                     }
                 }
             }
         } else {
             // non-blocking mode: wait for read to complete
             readLock.lock();
             readLock.unlock();
         }

         // set state to ST_KILLPENDING
         synchronized (stateLock) {
             assert state == ST_CLOSING;
             state = ST_KILLPENDING;
         }

         // close socket if not registered with Selector
         if (!isRegistered())
             kill();

         // restore interrupt status
         if (interrupted)
             Thread.currentThread().interrupt();
     }

     @Override
     public void kill() throws IOException {
         synchronized (stateLock) {
             assert thread == 0;
             if (state == ST_KILLPENDING) {
                 state = ST_KILLED;
                 nd.close(fd);
             }
         }
     }

     @Override
     protected void implConfigureBlocking(boolean block) throws IOException {
         readLock.lock();
         try {
             synchronized (stateLock) {
                 IOUtil.configureBlocking(fd, block);
             }
         } finally {
             readLock.unlock();
         }
     }

     public boolean translateReadyOps(int ops, int initialOps, SelectionKeyImpl ski) {
         int intOps = ski.nioInterestOps();
         int oldOps = ski.nioReadyOps();
         int newOps = initialOps;

         if ((ops & Net.POLLNVAL) != 0)
             throw new Error("POLLNVAL detected");

         if ((ops & (Net.POLLERR | Net.POLLHUP)) != 0) {
             newOps = intOps;
             ski.nioReadyOps(newOps);
             return (newOps & ~oldOps) != 0;
         }

         if (((ops & Net.POLLIN) != 0) &&
             ((intOps & SelectionKey.OP_READ) != 0))
             newOps |= SelectionKey.OP_READ;

         ski.nioReadyOps(newOps);
         return (newOps & ~oldOps) != 0;
     }

     public boolean translateAndUpdateReadyOps(int ops, SelectionKeyImpl ski) {
         return translateReadyOps(ops, ski.nioReadyOps(), ski);
     }

     public boolean translateAndSetReadyOps(int ops, SelectionKeyImpl ski) {
         return translateReadyOps(ops, 0, ski);
     }

     public int translateInterestOps(int ops) {
         int newOps = 0;
         if (ops == SelectionKey.OP_READ)
             newOps |= Net.POLLIN;
         return newOps;
     }

     /**
      * Marks the beginning of a read operation that might block.
      *
      * @throws ClosedChannelException if the channel is closed
      * @throws NotYetConnectedException if the channel is not yet connected
      */
     private void beginRead(boolean blocking) throws ClosedChannelException {
         if (blocking) {
             // set hook for Thread.interrupt
             begin();
         }
         synchronized (stateLock) {
             if (!isOpen())
                 throw new ClosedChannelException();
             if (blocking)
                 thread = NativeThread.current();
         }
     }

     /**
      * Marks the end of a read operation that may have blocked.
      *
      * @throws AsynchronousCloseException if the channel was closed due to this
      * thread being interrupted on a blocking read operation.
      */
     private void endRead(boolean blocking, boolean completed)
         throws AsynchronousCloseException
     {
         if (blocking) {
             synchronized (stateLock) {
                 thread = 0;
                 // notify any thread waiting in implCloseSelectableChannel
                 if (state == ST_CLOSING) {
                     stateLock.notifyAll();
                 }
             }
             // remove hook for Thread.interrupt
             end(completed);
         }
     }

     @Override
     public int read(ByteBuffer dst) throws IOException {
         Objects.requireNonNull(dst);

         readLock.lock();
         try {
             boolean blocking = isBlocking();
             int n = 0;
             try {
                 beginRead(blocking);
                 do {
                     n = IOUtil.read(fd, dst, -1, nd);
                 } while ((n == IOStatus.INTERRUPTED) && isOpen());
             } finally {
                 endRead(blocking, n > 0);
                 assert IOStatus.check(n);
             }
             return IOStatus.normalize(n);
         } finally {
             readLock.unlock();
         }
     }

     @Override
     public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
         Objects.checkFromIndexSize(offset, length, dsts.length);

         readLock.lock();
         try {
             boolean blocking = isBlocking();
             long n = 0;
             try {
                 beginRead(blocking);
                 do {
                     n = IOUtil.read(fd, dsts, offset, length, nd);
                 } while ((n == IOStatus.INTERRUPTED) && isOpen());
             } finally {
                 endRead(blocking, n > 0);
                 assert IOStatus.check(n);
             }
             return IOStatus.normalize(n);
         } finally {
             readLock.unlock();
         }
     }

     @Override
     public long read(ByteBuffer[] dsts) throws IOException {
         return read(dsts, 0, dsts.length);
     }
 }
	/*
	* Copyright (c) 2000, 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.FileDescriptor;
	import java.io.IOException;
	import java.nio.ByteBuffer;
	import java.nio.channels.AsynchronousCloseException;
	import java.nio.channels.ClosedChannelException;
	import java.nio.channels.NotYetConnectedException;
	import java.nio.channels.Pipe;
	import java.nio.channels.SelectionKey;
	import java.nio.channels.spi.SelectorProvider;
	import java.util.Objects;
	import java.util.concurrent.locks.ReentrantLock;

	class SourceChannelImpl
	extends Pipe.SourceChannel
	implements SelChImpl
	{
	// Used to make native read and write calls
	private static final NativeDispatcher nd = new FileDispatcherImpl();

	// The file descriptor associated with this channel
	private final FileDescriptor fd;
	private final int fdVal;

	// Lock held by current reading thread
	private final ReentrantLock readLock = new ReentrantLock();

	// Lock held by any thread that modifies the state fields declared below
	// DO NOT invoke a blocking I/O operation while holding this lock!
	private final Object stateLock = new Object();

	// -- The following fields are protected by stateLock

	// Channel state
	private static final int ST_INUSE = 0;
	private static final int ST_CLOSING = 1;
	private static final int ST_KILLPENDING = 2;
	private static final int ST_KILLED = 3;
	private int state;

	// ID of native thread doing read, for signalling
	private long thread;

	// -- End of fields protected by stateLock


	public FileDescriptor getFD() {
	return fd;
	}

	public int getFDVal() {
	return fdVal;
	}

	SourceChannelImpl(SelectorProvider sp, FileDescriptor fd) {
	super(sp);
	this.fd = fd;
	this.fdVal = IOUtil.fdVal(fd);
	}

	/**
	* Invoked by implCloseChannel to close the channel.
	*/
	@Override
	protected void implCloseSelectableChannel() throws IOException {
	assert !isOpen();

	boolean interrupted = false;
	boolean blocking;

	// set state to ST_CLOSING
	synchronized (stateLock) {
	assert state < ST_CLOSING;
	state = ST_CLOSING;
	blocking = isBlocking();
	}

	// wait for any outstanding read to complete
	if (blocking) {
	synchronized (stateLock) {
	assert state == ST_CLOSING;
	long th = thread;
	if (th != 0) {
	nd.preClose(fd);
	NativeThread.signal(th);

	// wait for read operation to end
	while (thread != 0) {
	try {
	stateLock.wait();
	} catch (InterruptedException e) {
	interrupted = true;
	}
	}
	}
	}
	} else {
	// non-blocking mode: wait for read to complete
	readLock.lock();
	readLock.unlock();
	}

	// set state to ST_KILLPENDING
	synchronized (stateLock) {
	assert state == ST_CLOSING;
	state = ST_KILLPENDING;
	}

	// close socket if not registered with Selector
	if (!isRegistered())
	kill();

	// restore interrupt status
	if (interrupted)
	Thread.currentThread().interrupt();
	}

	@Override
	public void kill() throws IOException {
	synchronized (stateLock) {
	assert thread == 0;
	if (state == ST_KILLPENDING) {
	state = ST_KILLED;
	nd.close(fd);
	}
	}
	}

	@Override
	protected void implConfigureBlocking(boolean block) throws IOException {
	readLock.lock();
	try {
	synchronized (stateLock) {
	IOUtil.configureBlocking(fd, block);
	}
	} finally {
	readLock.unlock();
	}
	}

	public boolean translateReadyOps(int ops, int initialOps, SelectionKeyImpl ski) {
	int intOps = ski.nioInterestOps();
	int oldOps = ski.nioReadyOps();
	int newOps = initialOps;

	if ((ops & Net.POLLNVAL) != 0)
	throw new Error("POLLNVAL detected");

	if ((ops & (Net.POLLERR \| Net.POLLHUP)) != 0) {
	newOps = intOps;
	ski.nioReadyOps(newOps);
	return (newOps & ~oldOps) != 0;
	}

	if (((ops & Net.POLLIN) != 0) &&
	((intOps & SelectionKey.OP_READ) != 0))
	newOps \|= SelectionKey.OP_READ;

	ski.nioReadyOps(newOps);
	return (newOps & ~oldOps) != 0;
	}

	public boolean translateAndUpdateReadyOps(int ops, SelectionKeyImpl ski) {
	return translateReadyOps(ops, ski.nioReadyOps(), ski);
	}

	public boolean translateAndSetReadyOps(int ops, SelectionKeyImpl ski) {
	return translateReadyOps(ops, 0, ski);
	}

	public int translateInterestOps(int ops) {
	int newOps = 0;
	if (ops == SelectionKey.OP_READ)
	newOps \|= Net.POLLIN;
	return newOps;
	}

	/**
	* Marks the beginning of a read operation that might block.
	*
	* @throws ClosedChannelException if the channel is closed
	* @throws NotYetConnectedException if the channel is not yet connected
	*/
	private void beginRead(boolean blocking) throws ClosedChannelException {
	if (blocking) {
	// set hook for Thread.interrupt
	begin();
	}
	synchronized (stateLock) {
	if (!isOpen())
	throw new ClosedChannelException();
	if (blocking)
	thread = NativeThread.current();
	}
	}

	/**
	* Marks the end of a read operation that may have blocked.
	*
	* @throws AsynchronousCloseException if the channel was closed due to this
	* thread being interrupted on a blocking read operation.
	*/
	private void endRead(boolean blocking, boolean completed)
	throws AsynchronousCloseException
	{
	if (blocking) {
	synchronized (stateLock) {
	thread = 0;
	// notify any thread waiting in implCloseSelectableChannel
	if (state == ST_CLOSING) {
	stateLock.notifyAll();
	}
	}
	// remove hook for Thread.interrupt
	end(completed);
	}
	}

	@Override
	public int read(ByteBuffer dst) throws IOException {
	Objects.requireNonNull(dst);

	readLock.lock();
	try {
	boolean blocking = isBlocking();
	int n = 0;
	try {
	beginRead(blocking);
	do {
	n = IOUtil.read(fd, dst, -1, nd);
	} while ((n == IOStatus.INTERRUPTED) && isOpen());
	} finally {
	endRead(blocking, n > 0);
	assert IOStatus.check(n);
	}
	return IOStatus.normalize(n);
	} finally {
	readLock.unlock();
	}
	}

	@Override
	public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
	Objects.checkFromIndexSize(offset, length, dsts.length);

	readLock.lock();
	try {
	boolean blocking = isBlocking();
	long n = 0;
	try {
	beginRead(blocking);
	do {
	n = IOUtil.read(fd, dsts, offset, length, nd);
	} while ((n == IOStatus.INTERRUPTED) && isOpen());
	} finally {
	endRead(blocking, n > 0);
	assert IOStatus.check(n);
	}
	return IOStatus.normalize(n);
	} finally {
	readLock.unlock();
	}
	}

	@Override
	public long read(ByteBuffer[] dsts) throws IOException {
	return read(dsts, 0, dsts.length);
	}
	}