/*
 * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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 */
package java.net;

import java.io.IOException;
import java.io.FileDescriptor;
import sun.net.ResourceManager;

/*
 * This class defines the plain SocketImpl that is used for all
 * Windows version lower than Vista. It adds support for IPv6 on
 * these platforms where available.
 *
 * For backward compatibility Windows platforms that do not have IPv6
 * support also use this implementation, and fd1 gets set to null
 * during socket creation.
 *
 * @author Chris Hegarty
 */

class TwoStacksPlainSocketImpl extends AbstractPlainSocketImpl
{
 /* second fd, used for ipv6 on windows only.
 * fd1 is used for listeners and for client sockets at initialization
 * until the socket is connected. Up to this point fd always refers
 * to the ipv4 socket and fd1 to the ipv6 socket. After the socket
 * becomes connected, fd always refers to the connected socket
 * (either v4 or v6) and fd1 is closed.
 *
 * For ServerSockets, fd always refers to the v4 listener and
 * fd1 the v6 listener.
 */
 private FileDescriptor fd1;

 /*
 * Needed for ipv6 on windows because we need to know
 * if the socket is bound to ::0 or 0.0.0.0, when a caller
 * asks for it. Otherwise we don't know which socket to ask.
 */
 private InetAddress anyLocalBoundAddr = null;

 /* to prevent starvation when listening on two sockets, this is
 * is used to hold the id of the last socket we accepted on.
 */
 private int lastfd = -1;

 // true if this socket is exclusively bound
 private final boolean exclusiveBind;

 // emulates SO_REUSEADDR when exclusiveBind is true
 private boolean isReuseAddress;

 static {
 initProto();
 }

 public TwoStacksPlainSocketImpl(boolean exclBind) {
 exclusiveBind = exclBind;
 }

 public TwoStacksPlainSocketImpl(FileDescriptor fd, boolean exclBind) {
 this.fd = fd;
 exclusiveBind = exclBind;
 }

 /**
 * Creates a socket with a boolean that specifies whether this
 * is a stream socket (true) or an unconnected UDP socket (false).
 */
 protected synchronized void create(boolean stream) throws IOException {
 fd1 = new FileDescriptor();
 try {
 super.create(stream);
 } catch (IOException e) {
 fd1 = null;
 throw e;
 }
 }

 /**
 * Binds the socket to the specified address of the specified local port.
 * @param address the address
 * @param port the port
 */
 protected synchronized void bind(InetAddress address, int lport)
 throws IOException
 {
 super.bind(address, lport);
 if (address.isAnyLocalAddress()) {
 anyLocalBoundAddr = address;
 }
 }

 public Object getOption(int opt) throws SocketException {
 if (isClosedOrPending()) {
 throw new SocketException("Socket Closed");
 }
 if (opt == SO_BINDADDR) {
 if (fd != null && fd1 != null ) {
 /* must be unbound or else bound to anyLocal */
 return anyLocalBoundAddr;
 }
 InetAddressContainer in = new InetAddressContainer();
 socketGetOption(opt, in);
 return in.addr;
 } else if (opt == SO_REUSEADDR && exclusiveBind) {
 // SO_REUSEADDR emulated when using exclusive bind
 return isReuseAddress;
 } else
 return super.getOption(opt);
 }

 @Override
 void socketBind(InetAddress address, int port) throws IOException {
 socketBind(address, port, exclusiveBind);
 }

 @Override
 void socketSetOption(int opt, boolean on, Object value)
 throws SocketException
 {
 // SO_REUSEADDR emulated when using exclusive bind
 if (opt == SO_REUSEADDR && exclusiveBind)
 isReuseAddress = on;
 else
 socketNativeSetOption(opt, on, value);
 }

 /**
 * Closes the socket.
 */
 @Override
 protected void close() throws IOException {
 synchronized(fdLock) {
 if (fd != null || fd1 != null) {
 if (!stream) {
 ResourceManager.afterUdpClose();
 }
 if (fdUseCount == 0) {
 if (closePending) {
 return;
 }
 closePending = true;
 socketClose();
 fd = null;
 fd1 = null;
 return;
 } else {
 /*
 * If a thread has acquired the fd and a close
 * isn't pending then use a deferred close.
 * Also decrement fdUseCount to signal the last
 * thread that releases the fd to close it.
 */
 if (!closePending) {
 closePending = true;
 fdUseCount--;
 socketClose();
 }
 }
 }
 }
 }

 @Override
 void reset() throws IOException {
 if (fd != null || fd1 != null) {
 socketClose();
 }
 fd = null;
 fd1 = null;
 super.reset();
 }

 /*
 * Return true if already closed or close is pending
 */
 @Override
 public boolean isClosedOrPending() {
 /*
 * Lock on fdLock to ensure that we wait if a
 * close is in progress.
 */
 synchronized (fdLock) {
 if (closePending || (fd == null && fd1 == null)) {
 return true;
 } else {
 return false;
 }
 }
 }

 /* Native methods */

 static native void initProto();

 native void socketCreate(boolean isServer) throws IOException;

 native void socketConnect(InetAddress address, int port, int timeout)
 throws IOException;

 native void socketBind(InetAddress address, int port, boolean exclBind)
 throws IOException;

 native void socketListen(int count) throws IOException;

 native void socketAccept(SocketImpl s) throws IOException;

 native int socketAvailable() throws IOException;

 native void socketClose0(boolean useDeferredClose) throws IOException;

 native void socketShutdown(int howto) throws IOException;

 native void socketNativeSetOption(int cmd, boolean on, Object value)
 throws SocketException;

 native int socketGetOption(int opt, Object iaContainerObj) throws SocketException;

 native void socketSendUrgentData(int data) throws IOException;
}