/*

 * 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.nio.ByteBuffer;

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

    // fd value needed for dev/poll. This value will remain valid

    // even after the value in the file descriptor object has been set to -1

    // ID of native thread doing read, for signalling

    private volatile long thread;

    // Lock held by current reading thread

    // 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_UNINITIALIZED = -1;

    private static final int ST_INUSE = 0;

    private static final int ST_KILLED = 1;

    private volatile int state = ST_UNINITIALIZED;

    // -- 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);

        this.state = ST_INUSE;

    }

    protected void implCloseSelectableChannel() throws IOException {

        synchronized (stateLock) {

            if (state != ST_KILLED)

                nd.preClose(fd);

            long th = thread;

            if (th != 0)

                NativeThread.signal(th);

            if (!isRegistered())

                kill();

        }

    }

    public void kill() throws IOException {

        synchronized (stateLock) {

            if (state == ST_KILLED)

                return;

            if (state == ST_UNINITIALIZED) {

                state = ST_KILLED;

                return;

            }

            assert !isOpen() && !isRegistered();

            nd.close(fd);

            state = ST_KILLED;

        }

    }

    protected void implConfigureBlocking(boolean block) throws IOException {

        IOUtil.configureBlocking(fd, block);

    }

    public boolean translateReadyOps(int ops, int initialOps,

                                     SelectionKeyImpl sk) {

        int intOps = sk.nioInterestOps(); // Do this just once, it synchronizes

        int oldOps = sk.nioReadyOps();

        int newOps = initialOps;

        if ((ops & Net.POLLNVAL) != 0)

            throw new Error("POLLNVAL detected");

        if ((ops & (Net.POLLERR | Net.POLLHUP)) != 0) {

            newOps = intOps;

            sk.nioReadyOps(newOps);

            return (newOps & ~oldOps) != 0;

        }

        if (((ops & Net.POLLIN) != 0) &&

            ((intOps & SelectionKey.OP_READ) != 0))

            newOps |= SelectionKey.OP_READ;

        sk.nioReadyOps(newOps);

        return (newOps & ~oldOps) != 0;

    }

    public boolean translateAndUpdateReadyOps(int ops, SelectionKeyImpl sk) {

        return translateReadyOps(ops, sk.nioReadyOps(), sk);

    }

    public boolean translateAndSetReadyOps(int ops, SelectionKeyImpl sk) {

        return translateReadyOps(ops, 0, sk);

    }

    public void translateAndSetInterestOps(int ops, SelectionKeyImpl sk) {

        if (ops == SelectionKey.OP_READ)

            ops = Net.POLLIN;

        sk.selector.putEventOps(sk, ops);

    }

    private void ensureOpen() throws IOException {

        if (!isOpen())

            throw new ClosedChannelException();

    }

    public int read(ByteBuffer dst) throws IOException {

            int n = 0;

            try {

                begin();

                if (!isOpen())

                    return 0;

                thread = NativeThread.current();

                do {

                    n = IOUtil.read(fd, dst, -1, nd);

                } while ((n == IOStatus.INTERRUPTED) && isOpen());

                return IOStatus.normalize(n);

            } finally {

                thread = 0;

                end((n > 0) || (n == IOStatus.UNAVAILABLE));

                assert IOStatus.check(n);

            }

        }

    }

    public long read(ByteBuffer[] dsts, int offset, int length)

        throws IOException

    {

        if ((offset < 0) || (length < 0) || (offset > dsts.length - length))

           throw new IndexOutOfBoundsException();

        return read(Util.subsequence(dsts, offset, length));

    }

    public long read(ByteBuffer[] dsts) throws IOException {

        if (dsts == null)

            throw new NullPointerException();

            long n = 0;

            try {

                begin();

                if (!isOpen())

                    return 0;

                thread = NativeThread.current();

                do {

                    n = IOUtil.read(fd, dsts, nd);

                } while ((n == IOStatus.INTERRUPTED) && isOpen());

                return IOStatus.normalize(n);

            } finally {

                thread = 0;

                end((n > 0) || (n == IOStatus.UNAVAILABLE));

                assert IOStatus.check(n);

            }

        }

    }

}