/*

 * Copyright (c) 2001, 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.IOException;

import java.lang.invoke.MethodHandles;

import java.lang.invoke.MethodHandles.Lookup;

import java.lang.invoke.VarHandle;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.DatagramSocketImpl;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import java.net.NetworkInterface;

import java.net.SocketAddress;

import java.net.SocketException;

import java.net.SocketOption;

import java.net.StandardSocketOptions;

import java.nio.ByteBuffer;

import java.nio.channels.AlreadyConnectedException;

import java.nio.channels.ClosedChannelException;

import java.nio.channels.DatagramChannel;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.Set;

import static java.util.concurrent.TimeUnit.MILLISECONDS;

// Make a datagram-socket channel look like a datagram socket.

//

// The methods in this class are defined in exactly the same order as in

// java.net.DatagramSocket so as to simplify tracking future changes to that

// class.

//

class DatagramSocketAdaptor

    extends DatagramSocket

{

    // The channel being adapted

    private final DatagramChannelImpl dc;

    // Timeout "option" value for receives

    private volatile int timeout;

    // create DatagramSocket with useless impl

    private DatagramSocketAdaptor(DatagramChannelImpl dc) {

        super(new DummyDatagramSocketImpl());

        this.dc = dc;

    }

    static DatagramSocket create(DatagramChannelImpl dc) {

        return new DatagramSocketAdaptor(dc);

    }

    private void connectInternal(SocketAddress remote) throws SocketException {

        try {

            dc.connect(remote, false); // skips check for already connected

        } catch (ClosedChannelException e) {

            // ignore

        } catch (Exception x) {

            Net.translateToSocketException(x);

        }

    }

    @Override

    public void bind(SocketAddress local) throws SocketException {

        if (local != null) {

            local = Net.asInetSocketAddress(local);

        } else {

            local = new InetSocketAddress(0);

        }

        try {

            dc.bind(local);

        } catch (Exception x) {

            Net.translateToSocketException(x);

        }

    }

    @Override

    public void connect(InetAddress address, int port) {

        if (address == null)

            throw new IllegalArgumentException("Address can't be null");

        try {

            connectInternal(new InetSocketAddress(address, port));

        } catch (SocketException x) {

            throw new Error(x);

        }

    }

    @Override

    public void connect(SocketAddress remote) throws SocketException {

        if (remote == null)

            throw new IllegalArgumentException("Address can't be null");

        connectInternal(Net.asInetSocketAddress(remote));

    }

    @Override

    public void disconnect() {

        try {

            dc.disconnect();

        } catch (IOException x) {

            throw new Error(x);

        }

    }

    @Override

    public boolean isBound() {

        return dc.localAddress() != null;

    }

    @Override

    public boolean isConnected() {

        return dc.remoteAddress() != null;

    }

    @Override

    public InetAddress getInetAddress() {

        InetSocketAddress remote = dc.remoteAddress();

        return (remote != null) ? remote.getAddress() : null;

    }

    @Override

    public int getPort() {

        InetSocketAddress remote = dc.remoteAddress();

        return (remote != null) ? remote.getPort() : -1;

    }

    @Override

    public SocketAddress getRemoteSocketAddress() {

        return dc.remoteAddress();

    }

    @Override

    public SocketAddress getLocalSocketAddress() {

        try {

            return dc.getLocalAddress();

        } catch (ClosedChannelException e) {

            return null;

        } catch (Exception x) {

            throw new Error(x);

        }

    }

    @Override

    public void send(DatagramPacket p) throws IOException {

        ByteBuffer bb = null;

        try {

            InetSocketAddress target;

            synchronized (p) {

                // copy bytes to temporary direct buffer

                int len = p.getLength();

                bb = Util.getTemporaryDirectBuffer(len);

                bb.put(p.getData(), p.getOffset(), len);

                bb.flip();

                // target address

                if (p.getAddress() == null) {

                    InetSocketAddress remote = dc.remoteAddress();

                    if (remote == null) {

                        // not specified by DatagramSocket

                        throw new IllegalArgumentException("Address not set");

                    }

                    // set address/port to maintain compatibility with DatagramSocket

                    p.setAddress(remote.getAddress());

                    p.setPort(remote.getPort());

                    target = remote;

                } else {

                    // throws IllegalArgumentException if port not set

                    target = (InetSocketAddress) p.getSocketAddress();

                }

            }

            // send datagram

            try {

                dc.blockingSend(bb, target);

            } catch (AlreadyConnectedException e) {

                throw new IllegalArgumentException("Connected and packet address differ");

            } catch (ClosedChannelException e) {

                var exc = new SocketException("Socket closed");

                exc.initCause(e);

                throw exc;

            }

        } finally {

            if (bb != null) {

                Util.offerFirstTemporaryDirectBuffer(bb);

            }

        }

    }

    @Override

    public void receive(DatagramPacket p) throws IOException {

        // get temporary direct buffer with a capacity of p.bufLength

        int bufLength = DatagramPackets.getBufLength(p);

        ByteBuffer bb = Util.getTemporaryDirectBuffer(bufLength);

        try {

            long nanos = MILLISECONDS.toNanos(timeout);

            SocketAddress sender = dc.blockingReceive(bb, nanos);

            bb.flip();

            synchronized (p) {

                // copy bytes to the DatagramPacket and set length

                int len = Math.min(bb.limit(), DatagramPackets.getBufLength(p));

                bb.get(p.getData(), p.getOffset(), len);

                DatagramPackets.setLength(p, len);

                // sender address

                p.setSocketAddress(sender);

            }

        } catch (ClosedChannelException e) {

            var exc = new SocketException("Socket closed");

            exc.initCause(e);

            throw exc;

        } finally {

            Util.offerFirstTemporaryDirectBuffer(bb);

        }

    }

    @Override

    public InetAddress getLocalAddress() {

        if (isClosed())

            return null;

        InetSocketAddress local = dc.localAddress();

        if (local == null)

            local = new InetSocketAddress(0);

        InetAddress result = local.getAddress();

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            try {

                sm.checkConnect(result.getHostAddress(), -1);

            } catch (SecurityException x) {

                return new InetSocketAddress(0).getAddress();

            }

        }

        return result;

    }

    @Override

    public int getLocalPort() {

        if (isClosed())

            return -1;

        InetSocketAddress local = dc.localAddress();

        if (local != null) {

            return local.getPort();

        }

        return 0;

    }

    @Override

    public void setSoTimeout(int timeout) throws SocketException {

        if (isClosed())

            throw new SocketException("Socket is closed");

        if (timeout < 0)

            throw new IllegalArgumentException("timeout < 0");

        this.timeout = timeout;

    }

    @Override

    public int getSoTimeout() throws SocketException {

        if (isClosed())

            throw new SocketException("Socket is closed");

        return timeout;

    }

    private void setBooleanOption(SocketOption<Boolean> name, boolean value)

        throws SocketException

    {

        try {

            dc.setOption(name, value);

        } catch (IOException x) {

            Net.translateToSocketException(x);

        }

    }

    private void setIntOption(SocketOption<Integer> name, int value)

        throws SocketException

    {

        try {

            dc.setOption(name, value);

        } catch (IOException x) {

            Net.translateToSocketException(x);

        }

    }

    private boolean getBooleanOption(SocketOption<Boolean> name) throws SocketException {

        try {

            return dc.getOption(name).booleanValue();

        } catch (IOException x) {

            Net.translateToSocketException(x);

            return false;       // keep compiler happy

        }

    }

    private int getIntOption(SocketOption<Integer> name) throws SocketException {

        try {

            return dc.getOption(name).intValue();

        } catch (IOException x) {

            Net.translateToSocketException(x);

            return -1;          // keep compiler happy

        }

    }

    @Override

    public void setSendBufferSize(int size) throws SocketException {

        if (size <= 0)

            throw new IllegalArgumentException("Invalid send size");

        setIntOption(StandardSocketOptions.SO_SNDBUF, size);

    }

    @Override

    public int getSendBufferSize() throws SocketException {

        return getIntOption(StandardSocketOptions.SO_SNDBUF);

    }

    @Override

    public void setReceiveBufferSize(int size) throws SocketException {

        if (size <= 0)

            throw new IllegalArgumentException("Invalid receive size");

        setIntOption(StandardSocketOptions.SO_RCVBUF, size);

    }

    @Override

    public int getReceiveBufferSize() throws SocketException {

        return getIntOption(StandardSocketOptions.SO_RCVBUF);

    }

    @Override

    public void setReuseAddress(boolean on) throws SocketException {

        setBooleanOption(StandardSocketOptions.SO_REUSEADDR, on);

    }

    @Override

    public boolean getReuseAddress() throws SocketException {

        return getBooleanOption(StandardSocketOptions.SO_REUSEADDR);

    }

    @Override

    public void setBroadcast(boolean on) throws SocketException {

        setBooleanOption(StandardSocketOptions.SO_BROADCAST, on);

    }

    @Override

    public boolean getBroadcast() throws SocketException {

        return getBooleanOption(StandardSocketOptions.SO_BROADCAST);

    }

    @Override

    public void setTrafficClass(int tc) throws SocketException {

        setIntOption(StandardSocketOptions.IP_TOS, tc);

    }

    @Override

    public int getTrafficClass() throws SocketException {

        return getIntOption(StandardSocketOptions.IP_TOS);

    }

    @Override

    public void close() {

        try {

            dc.close();

        } catch (IOException x) {

            throw new Error(x);

        }

    }

    @Override

    public boolean isClosed() {

        return !dc.isOpen();

    }

    @Override

    public DatagramChannel getChannel() {

        return dc;

    }

    @Override

    public <T> DatagramSocket setOption(SocketOption<T> name, T value) throws IOException {

        dc.setOption(name, value);

        return this;

    }

    @Override

    public <T> T getOption(SocketOption<T> name) throws IOException {

        return dc.getOption(name);

    }

    @Override

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

        return dc.supportedOptions();

    }

    /**

     * DatagramSocketImpl implementation where all methods throw an error.

     */

    private static class DummyDatagramSocketImpl extends DatagramSocketImpl {

        private static <T> T shouldNotGetHere() {

            throw new InternalError("Should not get here");

        }

        @Override

        protected void create() {

            shouldNotGetHere();

        }

        @Override

        protected void bind(int lport, InetAddress laddr) {

            shouldNotGetHere();

        }

        @Override

        protected void send(DatagramPacket p) {

            shouldNotGetHere();

        }

        @Override

        protected int peek(InetAddress address) {

            return shouldNotGetHere();

        }

        @Override

        protected int peekData(DatagramPacket p) {

            return shouldNotGetHere();

        }

        @Override

        protected void receive(DatagramPacket p) {

            shouldNotGetHere();

        }

        @Deprecated

        protected void setTTL(byte ttl) {

            shouldNotGetHere();

        }

        @Deprecated

        protected byte getTTL() {

            return shouldNotGetHere();

        }

        @Override

        protected void setTimeToLive(int ttl) {

            shouldNotGetHere();

        }

        @Override

        protected int getTimeToLive() {

            return shouldNotGetHere();

        }

        @Override

        protected void join(InetAddress group) {

            shouldNotGetHere();

        }

        @Override

        protected void leave(InetAddress inetaddr) {

            shouldNotGetHere();

        }

        @Override

        protected void joinGroup(SocketAddress group, NetworkInterface netIf) {

            shouldNotGetHere();

        }

        @Override

        protected void leaveGroup(SocketAddress mcastaddr, NetworkInterface netIf) {

            shouldNotGetHere();

        }

        @Override

        protected void close() {

            shouldNotGetHere();

        }

        @Override