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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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.
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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.
/** * 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:
/** * 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.
/** * 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); } }