/*

 * 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

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 */

package sun.nio.ch;

import java.lang.invoke.ConstantBootstraps;

import java.lang.invoke.MethodHandles;

import java.lang.invoke.VarHandle;

import java.nio.channels.CancelledKeyException;

import java.nio.channels.SelectableChannel;

import java.nio.channels.SelectionKey;

import java.nio.channels.Selector;

import java.nio.channels.spi.AbstractSelectionKey;

/**

 * An implementation of SelectionKey.

 */

public final class SelectionKeyImpl

    extends AbstractSelectionKey

{

    private static final VarHandle INTERESTOPS =

            ConstantBootstraps.fieldVarHandle(

                    MethodHandles.lookup(),

                    "interestOps",

                    VarHandle.class,

                    SelectionKeyImpl.class, int.class);

    private final SelChImpl channel;

    private final SelectorImpl selector;

    private volatile int interestOps;

    private volatile int readyOps;

    // registered events in kernel, used by some Selector implementations

    private int registeredEvents;

    // index of key in pollfd array, used by some Selector implementations

    private int index;

    SelectionKeyImpl(SelChImpl ch, SelectorImpl sel) {

        channel = ch;

        selector = sel;

    }

    private void ensureValid() {

        if (!isValid())

            throw new CancelledKeyException();

    }

    int getFDVal() {

        return channel.getFDVal();

    }

    @Override

    public SelectableChannel channel() {

        return (SelectableChannel)channel;

    }

    @Override

    public Selector selector() {

        return selector;

    }

    @Override

    public int interestOps() {

        ensureValid();

        return interestOps;

    }

    @Override

    public SelectionKey interestOps(int ops) {

        ensureValid();

        if ((ops & ~channel().validOps()) != 0)

            throw new IllegalArgumentException();

        int oldOps = (int) INTERESTOPS.getAndSet(this, ops);

        if (ops != oldOps) {

            selector.setEventOps(this);

        }

        return this;

    }

    @Override

    public int interestOpsOr(int ops) {

        ensureValid();

        if ((ops & ~channel().validOps()) != 0)

            throw new IllegalArgumentException();

        int oldVal = (int) INTERESTOPS.getAndBitwiseOr(this, ops);

        if (oldVal != (oldVal | ops)) {

            selector.setEventOps(this);

        }

        return oldVal;

    }

    @Override

    public int interestOpsAnd(int ops) {

        ensureValid();

        int oldVal = (int) INTERESTOPS.getAndBitwiseAnd(this, ops);

        if (oldVal != (oldVal & ops)) {

            selector.setEventOps(this);

        }

        return oldVal;

    }

    @Override

    public int readyOps() {

        ensureValid();

        return readyOps;

    }

    // The nio versions of these operations do not care if a key

    // has been invalidated. They are for internal use by nio code.

    public void nioReadyOps(int ops) {

        readyOps = ops;

    }

    public int nioReadyOps() {

        return readyOps;

    }

    public SelectionKey nioInterestOps(int ops) {

        if ((ops & ~channel().validOps()) != 0)

            throw new IllegalArgumentException();

        interestOps = ops;

        selector.setEventOps(this);

        return this;

    }

    public int nioInterestOps() {

        return interestOps;

    }

    int translateInterestOps() {

        return channel.translateInterestOps(interestOps);

    }

    boolean translateAndSetReadyOps(int ops) {

        return channel.translateAndSetReadyOps(ops, this);

    }

    boolean translateAndUpdateReadyOps(int ops) {

        return channel.translateAndUpdateReadyOps(ops, this);

    }

    void registeredEvents(int events) {

        // assert Thread.holdsLock(selector);

        this.registeredEvents = events;

    }

    int registeredEvents() {

        // assert Thread.holdsLock(selector);

        return registeredEvents;

    }

    int getIndex() {

        return index;

    }

    void setIndex(int i) {

        index = i;

    }

    @Override

    public String toString() {

        StringBuilder sb = new StringBuilder();

        sb.append("channel=")

          .append(channel)

          .append(", selector=")

          .append(selector);

        if (isValid()) {

            sb.append(", interestOps=")

              .append(interestOps)

              .append(", readyOps=")

              .append(readyOps);

        } else {

            sb.append(", invalid");

        }

        return sb.toString();

    }

    // used by Selector implementations to record when the key was selected

    int lastPolled;

}