/*

 * 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 java.net;

import java.io.IOException;

import java.io.InvalidObjectException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.io.ObjectStreamException;

import java.io.ObjectStreamField;

/**

 *

 * This class implements an IP Socket Address (IP address + port number)

 * It can also be a pair (hostname + port number), in which case an attempt

 * will be made to resolve the hostname. If resolution fails then the address

 * is said to be <I>unresolved</I> but can still be used on some circumstances

 * like connecting through a proxy.

 * <p>

 * It provides an immutable object used by sockets for binding, connecting, or

 * as returned values.

 * <p>

 * The <i>wildcard</i> is a special local IP address. It usually means "any"

 * and can only be used for {@code bind} operations.

 *

 * @see java.net.Socket

 * @see java.net.ServerSocket

 * @since 1.4

 */

public class InetSocketAddress

    extends SocketAddress

{

    // Private implementation class pointed to by all public methods.

    private static class InetSocketAddressHolder {

        // The hostname of the Socket Address

        private String hostname;

        // The IP address of the Socket Address

        private InetAddress addr;

        // The port number of the Socket Address

        private int port;

        private InetSocketAddressHolder(String hostname, InetAddress addr, int port) {

            this.hostname = hostname;

            this.addr = addr;

            this.port = port;

        }

        private int getPort() {

            return port;

        }

        private InetAddress getAddress() {

            return addr;

        }

        private String getHostName() {

            if (hostname != null)

                return hostname;

            if (addr != null)

                return addr.getHostName();

            return null;

        }

        private String getHostString() {

            if (hostname != null)

                return hostname;

            if (addr != null) {

                if (addr.holder().getHostName() != null)

                    return addr.holder().getHostName();

                else

                    return addr.getHostAddress();

            }

            return null;

        }

        private boolean isUnresolved() {

            return addr == null;

        }

        @Override

        public String toString() {

            if (isUnresolved()) {

            } else {

            }

        }

        @Override

        public final boolean equals(Object obj) {

            if (obj == null || !(obj instanceof InetSocketAddressHolder))

                return false;

            InetSocketAddressHolder that = (InetSocketAddressHolder)obj;

            boolean sameIP;

            if (addr != null)

                sameIP = addr.equals(that.addr);

            else if (hostname != null)

                sameIP = (that.addr == null) &&

                    hostname.equalsIgnoreCase(that.hostname);

            else

                sameIP = (that.addr == null) && (that.hostname == null);

            return sameIP && (port == that.port);

        }

        @Override

        public final int hashCode() {

            if (addr != null)

                return addr.hashCode() + port;

            if (hostname != null)

                return hostname.toLowerCase().hashCode() + port;

            return port;

        }

    }

    private final transient InetSocketAddressHolder holder;

    @java.io.Serial

    private static final long serialVersionUID = 5076001401234631237L;

    private static int checkPort(int port) {

        if (port < 0 || port > 0xFFFF)

            throw new IllegalArgumentException("port out of range:" + port);

        return port;

    }

    private static String checkHost(String hostname) {

        if (hostname == null)

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

        return hostname;

    }

    /**

     * Creates a socket address where the IP address is the wildcard address

     * and the port number a specified value.

     * <p>

     * A valid port value is between 0 and 65535.

     * A port number of {@code zero} will let the system pick up an

     * ephemeral port in a {@code bind} operation.

     *

     * @param   port    The port number

     * @throws IllegalArgumentException if the port parameter is outside the specified

     * range of valid port values.

     */

    public InetSocketAddress(int port) {

        this(InetAddress.anyLocalAddress(), port);

    }

    /**

     *

     * Creates a socket address from an IP address and a port number.

     * <p>

     * A valid port value is between 0 and 65535.

     * A port number of {@code zero} will let the system pick up an

     * ephemeral port in a {@code bind} operation.

     * <P>

     * A {@code null} address will assign the <i>wildcard</i> address.

     *

     * @param   addr    The IP address

     * @param   port    The port number

     * @throws IllegalArgumentException if the port parameter is outside the specified

     * range of valid port values.

     */

    public InetSocketAddress(InetAddress addr, int port) {

        holder = new InetSocketAddressHolder(

                        null,

                        addr == null ? InetAddress.anyLocalAddress() : addr,

                        checkPort(port));

    }

    /**

     *

     * Creates a socket address from a hostname and a port number.

     * <p>

     * An attempt will be made to resolve the hostname into an InetAddress.

     * If that attempt fails, the address will be flagged as <I>unresolved</I>.

     * <p>

     * If there is a security manager, its {@code checkConnect} method

     * is called with the host name as its argument to check the permission

     * to resolve it. This could result in a SecurityException.

     * <P>

     * A valid port value is between 0 and 65535.

     * A port number of {@code zero} will let the system pick up an

     * ephemeral port in a {@code bind} operation.

     *

     * @param   hostname the Host name

     * @param   port    The port number

     * @throws IllegalArgumentException if the port parameter is outside the range

     * of valid port values, or if the hostname parameter is {@code null}.

     * @throws SecurityException if a security manager is present and

     *                           permission to resolve the host name is

     *                           denied.

     * @see     #isUnresolved()

     */

    public InetSocketAddress(String hostname, int port) {

        checkHost(hostname);

        InetAddress addr = null;

        String host = null;

        try {

            addr = InetAddress.getByName(hostname);

        } catch(UnknownHostException e) {

            host = hostname;

        }

        holder = new InetSocketAddressHolder(host, addr, checkPort(port));

    }

    // private constructor for creating unresolved instances

    private InetSocketAddress(int port, String hostname) {

        holder = new InetSocketAddressHolder(hostname, null, port);

    }

    /**

     *

     * Creates an unresolved socket address from a hostname and a port number.

     * <p>

     * No attempt will be made to resolve the hostname into an InetAddress.

     * The address will be flagged as <I>unresolved</I>.

     * <p>

     * A valid port value is between 0 and 65535.

     * A port number of {@code zero} will let the system pick up an

     * ephemeral port in a {@code bind} operation.

     *

     * @param   host    the Host name

     * @param   port    The port number

     * @throws IllegalArgumentException if the port parameter is outside

     *                  the range of valid port values, or if the hostname

     *                  parameter is {@code null}.

     * @see     #isUnresolved()

     * @return  an {@code InetSocketAddress} representing the unresolved

     *          socket address

     * @since 1.5

     */

    public static InetSocketAddress createUnresolved(String host, int port) {

        return new InetSocketAddress(checkPort(port), checkHost(host));

    }

    /**

     * @serialField hostname String

     * @serialField addr InetAddress

     * @serialField port int

     */

    @java.io.Serial

    private static final ObjectStreamField[] serialPersistentFields = {

         new ObjectStreamField("hostname", String.class),

         new ObjectStreamField("addr", InetAddress.class),

         new ObjectStreamField("port", int.class)};

    @java.io.Serial

    private void writeObject(ObjectOutputStream out)

        throws IOException

    {

        // Don't call defaultWriteObject()

         ObjectOutputStream.PutField pfields = out.putFields();

         pfields.put("hostname", holder.hostname);

         pfields.put("addr", holder.addr);

         pfields.put("port", holder.port);

         out.writeFields();

     }

    @java.io.Serial

    private void readObject(ObjectInputStream in)

        throws IOException, ClassNotFoundException

    {

        // Don't call defaultReadObject()

        ObjectInputStream.GetField oisFields = in.readFields();

        final String oisHostname = (String)oisFields.get("hostname", null);

        final InetAddress oisAddr = (InetAddress)oisFields.get("addr", null);

        final int oisPort = oisFields.get("port", -1);

        // Check that our invariants are satisfied

        checkPort(oisPort);

        if (oisHostname == null && oisAddr == null)

            throw new InvalidObjectException("hostname and addr " +

                                             "can't both be null");

        InetSocketAddressHolder h = new InetSocketAddressHolder(oisHostname,

                                                                oisAddr,

                                                                oisPort);

        UNSAFE.putReference(this, FIELDS_OFFSET, h);

    }

    @java.io.Serial

    private void readObjectNoData()

        throws ObjectStreamException

    {

        throw new InvalidObjectException("Stream data required");

    }

    private static final jdk.internal.misc.Unsafe UNSAFE

            = jdk.internal.misc.Unsafe.getUnsafe();

    private static final long FIELDS_OFFSET

            = UNSAFE.objectFieldOffset(InetSocketAddress.class, "holder");

    /**

     * Gets the port number.

     *

     * @return the port number.

     */

    public final int getPort() {

        return holder.getPort();

    }

    /**

     * Gets the {@code InetAddress}.

     *

     * @return the InetAddress or {@code null} if it is unresolved.

     */

    public final InetAddress getAddress() {

        return holder.getAddress();

    }

    /**

     * Gets the {@code hostname}.

     * Note: This method may trigger a name service reverse lookup if the

     * address was created with a literal IP address.

     *

     * @return  the hostname part of the address.

     */

    public final String getHostName() {

        return holder.getHostName();

    }

    /**

     * Returns the hostname, or the String form of the address if it

     * doesn't have a hostname (it was created using a literal).

     * This has the benefit of <b>not</b> attempting a reverse lookup.

     *

     * @return the hostname, or String representation of the address.

     * @since 1.7

     */

    public final String getHostString() {

        return holder.getHostString();

    }

    /**

     * Checks whether the address has been resolved or not.

     *

     * @return {@code true} if the hostname couldn't be resolved into

     *          an {@code InetAddress}.

     */

    public final boolean isUnresolved() {

        return holder.isUnresolved();

    }

    /**

     * Constructs a string representation of this InetSocketAddress.

     * This String is constructed by calling toString() on the InetAddress

     * and concatenating the port number (with a colon). If the address

     *

     * @return  a string representation of this object.

     */

    @Override

    public String toString() {

        return holder.toString();

    }

    /**

     * Compares this object against the specified object.

     * The result is {@code true} if and only if the argument is

     * not {@code null} and it represents the same address as

     * this object.

     * <p>

     * Two instances of {@code InetSocketAddress} represent the same

     * address if both the InetAddresses (or hostnames if it is unresolved) and port

     * numbers are equal.

     * If both addresses are unresolved, then the hostname and the port number

     * are compared.

     *

     * Note: Hostnames are case insensitive. e.g. "FooBar" and "foobar" are

     * considered equal.

     *

     * @param   obj   the object to compare against.

     * @return  {@code true} if the objects are the same;

     *          {@code false} otherwise.

     * @see java.net.InetAddress#equals(java.lang.Object)

     */

    @Override

    public final boolean equals(Object obj) {

        if (obj == null || !(obj instanceof InetSocketAddress))

            return false;

        return holder.equals(((InetSocketAddress) obj).holder);

    }

    /**

     * Returns a hashcode for this socket address.

     *

     * @return  a hash code value for this socket address.

     */

    @Override

    public final int hashCode() {

        return holder.hashCode();

    }

}