/*
 * Copyright (c) 1994, 2016, 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
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 */
package sun.net;

import java.io.*;
import java.net.Socket;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.net.Proxy;
import java.util.Arrays;
import java.security.AccessController;
import java.security.PrivilegedAction;

This is the base class for network clients.
Author:
     Jonathan Payne/**
 * This is the base class for network clients.
 *
 * @author      Jonathan Payne
 */
public class NetworkClient {
    /* Default value of read timeout, if not specified (infinity) */
    public static final int DEFAULT_READ_TIMEOUT = -1;

    /* Default value of connect timeout, if not specified (infinity) */
    public static final int DEFAULT_CONNECT_TIMEOUT = -1;

    protected Proxy     proxy = Proxy.NO_PROXY;
    
Socket for communicating with server. /** Socket for communicating with server. */
    protected Socket    serverSocket = null;

    
Stream for printing to the server. /** Stream for printing to the server. */
    public PrintStream  serverOutput;

    
Buffered stream for reading replies from server. /** Buffered stream for reading replies from server. */
    public InputStream  serverInput;

    protected static int defaultSoTimeout;
    protected static int defaultConnectTimeout;

    protected int readTimeout = DEFAULT_READ_TIMEOUT;
    protected int connectTimeout = DEFAULT_CONNECT_TIMEOUT;
    /* Name of encoding to use for output */
    protected static String encoding;

    static {
        final int vals[] = {0, 0};
        final String encs[] = { null };

        AccessController.doPrivileged(
                new PrivilegedAction<>() {
                    public Void run() {
                        vals[0] = Integer.getInteger("sun.net.client.defaultReadTimeout", 0).intValue();
                        vals[1] = Integer.getInteger("sun.net.client.defaultConnectTimeout", 0).intValue();
                        encs[0] = System.getProperty("file.encoding", "ISO8859_1");
                        return null;
            }
        });
        if (vals[0] != 0) {
            defaultSoTimeout = vals[0];
        }
        if (vals[1] != 0) {
            defaultConnectTimeout = vals[1];
        }

        encoding = encs[0];
        try {
            if (!isASCIISuperset (encoding)) {
                encoding = "ISO8859_1";
            }
        } catch (Exception e) {
            encoding = "ISO8859_1";
        }
    }


    
Test the named character encoding to verify that it converts ASCII
characters correctly. We have to use an ASCII based encoding, or else
the NetworkClients will not work correctly in EBCDIC based systems.
However, we cannot just use ASCII or ISO8859_1 universally, because in
Asian locales, non-ASCII characters may be embedded in otherwise
ASCII based protocols (eg. HTTP). The specifications (RFC2616, 2398)
are a little ambiguous in this matter. For instance, RFC2398 [part 2.1]
says that the HTTP request URI should be escaped using a defined
mechanism, but there is no way to specify in the escaped string what
the original character set is. It is not correct to assume that
UTF-8 is always used (as in URLs in HTML 4.0).  For this reason,
until the specifications are updated to deal with this issue more
comprehensively, and more importantly, HTTP servers are known to
support these mechanisms, we will maintain the current behavior
where it is possible to send non-ASCII characters in their original
unescaped form.
/**
     * Test the named character encoding to verify that it converts ASCII
     * characters correctly. We have to use an ASCII based encoding, or else
     * the NetworkClients will not work correctly in EBCDIC based systems.
     * However, we cannot just use ASCII or ISO8859_1 universally, because in
     * Asian locales, non-ASCII characters may be embedded in otherwise
     * ASCII based protocols (eg. HTTP). The specifications (RFC2616, 2398)
     * are a little ambiguous in this matter. For instance, RFC2398 [part 2.1]
     * says that the HTTP request URI should be escaped using a defined
     * mechanism, but there is no way to specify in the escaped string what
     * the original character set is. It is not correct to assume that
     * UTF-8 is always used (as in URLs in HTML 4.0).  For this reason,
     * until the specifications are updated to deal with this issue more
     * comprehensively, and more importantly, HTTP servers are known to
     * support these mechanisms, we will maintain the current behavior
     * where it is possible to send non-ASCII characters in their original
     * unescaped form.
     */
    private static boolean isASCIISuperset (String encoding) throws Exception {
        String chkS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"+
                        "abcdefghijklmnopqrstuvwxyz-_.!~*'();/?:@&=+$,";

        // Expected byte sequence for string above
        byte[] chkB = { 48,49,50,51,52,53,54,55,56,57,65,66,67,68,69,70,71,72,
                73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,97,98,99,
                100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,
                115,116,117,118,119,120,121,122,45,95,46,33,126,42,39,40,41,59,
                47,63,58,64,38,61,43,36,44};

        byte[] b = chkS.getBytes (encoding);
        return Arrays.equals (b, chkB);
    }

    
Open a connection to the server. /** Open a connection to the server. */
    public void openServer(String server, int port)
        throws IOException, UnknownHostException {
        if (serverSocket != null)
            closeServer();
        serverSocket = doConnect (server, port);
        try {
            serverOutput = new PrintStream(new BufferedOutputStream(
                                        serverSocket.getOutputStream()),
                                        true, encoding);
        } catch (UnsupportedEncodingException e) {
            throw new InternalError(encoding +"encoding not found", e);
        }
        serverInput = new BufferedInputStream(serverSocket.getInputStream());
    }

    
Return a socket connected to the server, with any
appropriate options pre-established
/**
     * Return a socket connected to the server, with any
     * appropriate options pre-established
     */
    protected Socket doConnect (String server, int port)
    throws IOException, UnknownHostException {
        Socket s;
        if (proxy != null) {
            if (proxy.type() == Proxy.Type.SOCKS) {
                s = AccessController.doPrivileged(
                    new PrivilegedAction<>() {
                        public Socket run() {
                                       return new Socket(proxy);
                                   }});
            } else if (proxy.type() == Proxy.Type.DIRECT) {
                s = createSocket();
            } else {
                // Still connecting through a proxy
                // server & port will be the proxy address and port
                s = new Socket(Proxy.NO_PROXY);
            }
        } else {
            s = createSocket();
        }

        // Instance specific timeouts do have priority, that means
        // connectTimeout & readTimeout (-1 means not set)
        // Then global default timeouts
        // Then no timeout.
        if (connectTimeout >= 0) {
            s.connect(new InetSocketAddress(server, port), connectTimeout);
        } else {
            if (defaultConnectTimeout > 0) {
                s.connect(new InetSocketAddress(server, port), defaultConnectTimeout);
            } else {
                s.connect(new InetSocketAddress(server, port));
            }
        }
        if (readTimeout >= 0)
            s.setSoTimeout(readTimeout);
        else if (defaultSoTimeout > 0) {
            s.setSoTimeout(defaultSoTimeout);
        }
        return s;
    }

    
The following method, createSocket, is provided to allow the
https client to override it so that it may use its socket factory
to create the socket.
/**
     * The following method, createSocket, is provided to allow the
     * https client to override it so that it may use its socket factory
     * to create the socket.
     */
    protected Socket createSocket() throws IOException {
        return new java.net.Socket(Proxy.NO_PROXY);  // direct connection
    }

    protected InetAddress getLocalAddress() throws IOException {
        if (serverSocket == null)
            throw new IOException("not connected");
        return  AccessController.doPrivileged(
                        new PrivilegedAction<>() {
                            public InetAddress run() {
                                return serverSocket.getLocalAddress();

                            }
                        });
    }

    
Close an open connection to the server. /** Close an open connection to the server. */
    public void closeServer() throws IOException {
        if (! serverIsOpen()) {
            return;
        }
        serverSocket.close();
        serverSocket = null;
        serverInput = null;
        serverOutput = null;
    }

    
Return server connection status /** Return server connection status */
    public boolean serverIsOpen() {
        return serverSocket != null;
    }

    
Create connection with host host on port port /** Create connection with host <i>host</i> on port <i>port</i> */
    public NetworkClient(String host, int port) throws IOException {
        openServer(host, port);
    }

    public NetworkClient() {}

    public void setConnectTimeout(int timeout) {
        connectTimeout = timeout;
    }

    public int getConnectTimeout() {
        return connectTimeout;
    }

    
Sets the read timeout.
Note: Public URLConnection (and protocol specific implementations)
protect against negative timeout values being set. This implementation,
and protocol specific implementations, use -1 to represent the default
read timeout.
This method may be invoked with the default timeout value when the
protocol handler is trying to reset the timeout after doing a
potentially blocking internal operation, e.g. cleaning up unread
response data, buffering error stream response data, etc
/**
     * Sets the read timeout.
     *
     * Note: Public URLConnection (and protocol specific implementations)
     * protect against negative timeout values being set. This implementation,
     * and protocol specific implementations, use -1 to represent the default
     * read timeout.
     *
     * This method may be invoked with the default timeout value when the
     * protocol handler is trying to reset the timeout after doing a
     * potentially blocking internal operation, e.g. cleaning up unread
     * response data, buffering error stream response data, etc
     */
    public void setReadTimeout(int timeout) {
        if (timeout == DEFAULT_READ_TIMEOUT)
            timeout = defaultSoTimeout;

        if (serverSocket != null && timeout >= 0) {
            try {
                serverSocket.setSoTimeout(timeout);
            } catch(IOException e) {
                // We tried...
            }
        }
        readTimeout = timeout;
    }

    public int getReadTimeout() {
        return readTimeout;
    }
}