/*

 * Copyright (c) 2000, 2019, 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.net.InetSocketAddress;

import java.net.ServerSocket;

import java.net.SocketAddress;

import java.net.SocketOption;

import java.net.SocketTimeoutException;

import java.net.StandardSocketOptions;

import java.nio.channels.AlreadyBoundException;

import java.nio.channels.AsynchronousCloseException;

import java.nio.channels.ClosedChannelException;

import java.nio.channels.IllegalBlockingModeException;

import java.nio.channels.NotYetBoundException;

import java.nio.channels.SelectionKey;

import java.nio.channels.ServerSocketChannel;

import java.nio.channels.SocketChannel;

import java.nio.channels.spi.SelectorProvider;

import java.util.Collections;

import java.util.HashSet;

import java.util.Objects;

import java.util.Set;

import java.util.concurrent.locks.ReentrantLock;

import sun.net.NetHooks;

import sun.net.ext.ExtendedSocketOptions;

/**

 * An implementation of ServerSocketChannels

 */

class InetServerSocketChannelImpl

    extends ServerSocketChannelImpl

{

    // set true when exclusive binding is on and SO_REUSEADDR is emulated

    private boolean isReuseAddress;

    // Our socket adaptor, if any

    private ServerSocket socket;

    // -- End of fields protected by stateLock

    InetServerSocketChannelImpl(SelectorProvider sp) throws IOException {

        super(sp, Net.serverSocket(true));

    }

    InetServerSocketChannelImpl(SelectorProvider sp, FileDescriptor fd, boolean bound)

        throws IOException

    {

        super(sp, fd);

        if (bound) {

            synchronized (stateLock) {

                localAddress = Net.localAddress(fd);

            }

        }

    }

    @Override

    public ServerSocket socket() {

        synchronized (stateLock) {

            if (socket == null)

                socket = ServerSocketAdaptor.create(this);

            return socket;

        }

    }

    @Override

    public <T> ServerSocketChannel setOption(SocketOption<T> name, T value)

        throws IOException

    {

        Objects.requireNonNull(name);

        if (!supportedOptions().contains(name))

            throw new UnsupportedOperationException("'" + name + "' not supported");

        if (!name.type().isInstance(value))

            throw new IllegalArgumentException("Invalid value '" + value + "'");

        synchronized (stateLock) {

            ensureOpen();

            if (name == StandardSocketOptions.SO_REUSEADDR && Net.useExclusiveBind()) {

                // SO_REUSEADDR emulated when using exclusive bind

                isReuseAddress = (Boolean)value;

            } else {

                // no options that require special handling

                Net.setSocketOption(fd, Net.UNSPEC, name, value);

            }

            return this;

        }

    }

    @Override

    @SuppressWarnings("unchecked")

    public <T> T getOption(SocketOption<T> name)

        throws IOException

    {

        Objects.requireNonNull(name);

        if (!supportedOptions().contains(name))

            throw new UnsupportedOperationException("'" + name + "' not supported");

        synchronized (stateLock) {

            ensureOpen();

            if (name == StandardSocketOptions.SO_REUSEADDR && Net.useExclusiveBind()) {

                // SO_REUSEADDR emulated when using exclusive bind

                return (T)Boolean.valueOf(isReuseAddress);

            }

            // no options that require special handling

            return (T) Net.getSocketOption(fd, Net.UNSPEC, name);

        }

    }

    private static class DefaultOptionsHolder {

        static final Set<SocketOption<?>> defaultOptions = defaultOptions();

        private static Set<SocketOption<?>> defaultOptions() {

            HashSet<SocketOption<?>> set = new HashSet<>();

            set.add(StandardSocketOptions.SO_RCVBUF);

            set.add(StandardSocketOptions.SO_REUSEADDR);

            if (Net.isReusePortAvailable()) {

                set.add(StandardSocketOptions.SO_REUSEPORT);

            }

            set.addAll(ExtendedSocketOptions.serverSocketOptions());

            return Collections.unmodifiableSet(set);

        }

    }

    @Override

    public final Set<SocketOption<?>> supportedOptions() {

        return DefaultOptionsHolder.defaultOptions;

    }

    @Override

    public ServerSocketChannel bind(SocketAddress local, int backlog) throws IOException {

        synchronized (stateLock) {

            ensureOpen();

            if (localAddress != null)

                throw new AlreadyBoundException();

            InetSocketAddress isa = (local == null)

                                    ? new InetSocketAddress(0)

                                    : Net.checkAddress(local);

            SecurityManager sm = System.getSecurityManager();

            if (sm != null)

                sm.checkListen(isa.getPort());

            NetHooks.beforeTcpBind(fd, isa.getAddress(), isa.getPort());

            Net.bind(fd, isa.getAddress(), isa.getPort());

            Net.listen(fd, backlog < 1 ? 50 : backlog);

            localAddress = Net.localAddress(fd);

        }

        return this;

    }

    protected int implAccept(FileDescriptor fd, FileDescriptor newfd, SocketAddress[] addrs)

        throws IOException

    {

        InetSocketAddress[] a = new InetSocketAddress[1];

        int n = Net.accept(fd, newfd, a);

        addrs[0] = a[0];

        return n;

    }

    protected SocketAddress getRevealedLocalAddress(SocketAddress addr) {

        return Net.getRevealedLocalAddress((InetSocketAddress)addr);

    }

    protected String getRevealedLocalAddressAsString(SocketAddress addr) {

        return Net.getRevealedLocalAddressAsString((InetSocketAddress)addr);

    }

    protected SocketChannel finishAccept(FileDescriptor newfd, SocketAddress sa)

        throws IOException

    {

        InetSocketAddress isa = (InetSocketAddress)sa;

        try {

            // newly accepted socket is initially in blocking mode

            IOUtil.configureBlocking(newfd, true);

            // check permitted to accept connections from the remote address

            SecurityManager sm = System.getSecurityManager();

            if (sm != null) {

                sm.checkAccept(isa.getAddress().getHostAddress(), isa.getPort());

            }

            return new InetSocketChannelImpl(provider(), newfd, isa);

        } catch (Exception e) {

            nd.close(newfd);

            throw e;

        }

    }

}