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 * Copyright (c) 2003, 2018 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.spi;

import java.net.InetSocketAddress;

import java.net.Proxy;

import java.net.ProxySelector;

import java.net.SocketAddress;

import java.net.URI;

import java.util.Collections;

import java.util.List;

import java.io.IOException;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.StringJoiner;

import java.util.regex.Pattern;

import java.util.stream.Stream;

import sun.net.NetProperties;

import sun.net.SocksProxy;

import static java.util.regex.Pattern.quote;

import static java.util.stream.Collectors.collectingAndThen;

import static java.util.stream.Collectors.toList;

/**

 * Supports proxy settings using system properties This proxy selector

 * provides backward compatibility with the old http protocol handler

 * as far as how proxy is set

 *

 * Most of the implementation copied from the old http protocol handler

 *

 * Supports http/https/ftp.proxyHost, http/https/ftp.proxyPort,

 * proxyHost, proxyPort, and http/https/ftp.nonProxyHost, and socks.

 */

public class DefaultProxySelector extends ProxySelector {

    /**

     * This is where we define all the valid System Properties we have to

     * support for each given protocol.

     * The format of this 2 dimensional array is :

     * - 1 row per protocol (http, ftp, ...)

     * - 1st element of each row is the protocol name

     * - subsequent elements are prefixes for Host & Port properties

     *   listed in order of priority.

     * Example:

     * {"ftp", "ftp.proxy", "ftpProxy", "proxy", "socksProxy"},

     * means for FTP we try in that oder:

     *          + ftp.proxyHost & ftp.proxyPort

     *          + ftpProxyHost & ftpProxyPort

     *          + proxyHost & proxyPort

     *          + socksProxyHost & socksProxyPort

     *

     * Note that the socksProxy should *always* be the last on the list

     */

    static final String[][] props = {

        /*

         * protocol, Property prefix 1, Property prefix 2, ...

         */

        {"http", "http.proxy", "proxy", "socksProxy"},

        {"https", "https.proxy", "proxy", "socksProxy"},

        {"ftp", "ftp.proxy", "ftpProxy", "proxy", "socksProxy"},

        {"socket", "socksProxy"}

    };

    private static final String SOCKS_PROXY_VERSION = "socksProxyVersion";

    private static boolean hasSystemProxies = false;

    private static final List<Proxy> NO_PROXY_LIST = List.of(Proxy.NO_PROXY);

    static {

        final String key = "java.net.useSystemProxies";

        Boolean b = AccessController.doPrivileged(

            new PrivilegedAction<Boolean>() {

                public Boolean run() {

                    return NetProperties.getBoolean(key);

                }});

        if (b != null && b.booleanValue()) {

            java.security.AccessController.doPrivileged(

                new java.security.PrivilegedAction<Void>() {

                    public Void run() {

                        System.loadLibrary("net");

                        return null;

                    }

                });

            hasSystemProxies = init();

        }

    }

    public static int socksProxyVersion() {

        return AccessController.doPrivileged(

                new PrivilegedAction<Integer>() {

                    @Override public Integer run() {

                        return NetProperties.getInteger(SOCKS_PROXY_VERSION, 5);

                    }

                });

    }

    /**

     * How to deal with "non proxy hosts":

     * since we do have to generate a pattern we don't want to do that if

     * it's not necessary. Therefore we do cache the result, on a per-protocol

     * basis, and change it only when the "source", i.e. the system property,

     * did change.

     */

    static class NonProxyInfo {

        // Default value for nonProxyHosts, this provides backward compatibility

        // by excluding localhost and its litteral notations.

        static final String defStringVal = "localhost|127.*|[::1]|0.0.0.0|[::0]";

        String hostsSource;

        Pattern pattern;

        final String property;

        final String defaultVal;

        static NonProxyInfo ftpNonProxyInfo = new NonProxyInfo("ftp.nonProxyHosts", null, null, defStringVal);

        static NonProxyInfo httpNonProxyInfo = new NonProxyInfo("http.nonProxyHosts", null, null, defStringVal);

        static NonProxyInfo socksNonProxyInfo = new NonProxyInfo("socksNonProxyHosts", null, null, defStringVal);

        NonProxyInfo(String p, String s, Pattern pattern, String d) {

            property = p;

            hostsSource = s;

            this.pattern = pattern;

            defaultVal = d;

        }

    }

    /**

     * select() method. Where all the hard work is done.

     * Build a list of proxies depending on URI.

     * Since we're only providing compatibility with the system properties

     * from previous releases (see list above), that list will typically

     * contain one single proxy, default being NO_PROXY.

     * If we can get a system proxy it might contain more entries.

     */

    public java.util.List<Proxy> select(URI uri) {

        if (uri == null) {

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

        }

        String protocol = uri.getScheme();

        String host = uri.getHost();

        if (host == null) {

            // This is a hack to ensure backward compatibility in two

            // cases: 1. hostnames contain non-ascii characters,

            // internationalized domain names. in which case, URI will

            // return null, see BugID 4957669; 2. Some hostnames can

            // contain '_' chars even though it's not supposed to be

            // legal, in which case URI will return null for getHost,

            // but not for getAuthority() See BugID 4913253

            String auth = uri.getAuthority();

            if (auth != null) {

                int i;

                i = auth.indexOf('@');

                if (i >= 0) {

                    auth = auth.substring(i+1);

                }

                i = auth.lastIndexOf(':');

                if (i >= 0) {

                    auth = auth.substring(0,i);

                }

                host = auth;

            }

        }

        if (protocol == null || host == null) {

            throw new IllegalArgumentException("protocol = "+protocol+" host = "+host);

        }

        NonProxyInfo pinfo = null;

        if ("http".equalsIgnoreCase(protocol)) {

            pinfo = NonProxyInfo.httpNonProxyInfo;

        } else if ("https".equalsIgnoreCase(protocol)) {

            // HTTPS uses the same property as HTTP, for backward

            // compatibility

            pinfo = NonProxyInfo.httpNonProxyInfo;

        } else if ("ftp".equalsIgnoreCase(protocol)) {

            pinfo = NonProxyInfo.ftpNonProxyInfo;

        } else if ("socket".equalsIgnoreCase(protocol)) {

            pinfo = NonProxyInfo.socksNonProxyInfo;

        }

        /**

         * Let's check the System properties for that protocol

         */

        final String proto = protocol;

        final NonProxyInfo nprop = pinfo;

        final String urlhost = host.toLowerCase();

        /**

         * This is one big doPrivileged call, but we're trying to optimize

         * the code as much as possible. Since we're checking quite a few

         * System properties it does help having only 1 call to doPrivileged.

         * Be mindful what you do in here though!

         */

        Proxy[] proxyArray = AccessController.doPrivileged(

            new PrivilegedAction<Proxy[]>() {

                public Proxy[] run() {

                    int i, j;

                    String phost =  null;

                    int pport = 0;

                    String nphosts =  null;

                    InetSocketAddress saddr = null;

                    // Then let's walk the list of protocols in our array

                    for (i=0; i<props.length; i++) {

                        if (props[i][0].equalsIgnoreCase(proto)) {

                            for (j = 1; j < props[i].length; j++) {

                                /* System.getProp() will give us an empty

                                 * String, "" for a defined but "empty"

                                 * property.

                                 */

                                phost =  NetProperties.get(props[i][j]+"Host");

                                if (phost != null && phost.length() != 0)

                                    break;

                            }

                                /**

                                 * No system property defined for that

                                 * protocol. Let's check System Proxy

                                 * settings (Gnome, MacOsX & Windows) if

                                 * we were instructed to.

                                 */

                                if (hasSystemProxies) {

                                    String sproto;

                                    if (proto.equalsIgnoreCase("socket"))

                                        sproto = "socks";

                                    else

                                        sproto = proto;

                                    return getSystemProxies(sproto, urlhost);

                                }

                                return null;

                            }

                            // If a Proxy Host is defined for that protocol

                            // Let's get the NonProxyHosts property

                            if (nprop != null) {

                                nphosts = NetProperties.get(nprop.property);

                                synchronized (nprop) {

                                    if (nphosts == null) {

                                        if (nprop.defaultVal != null) {

                                            nphosts = nprop.defaultVal;

                                        } else {

                                            nprop.hostsSource = null;

                                            nprop.pattern = null;

                                        }

                                        // add the required default patterns

                                        // but only if property no set. If it

                                        // is empty, leave empty.

                                        nphosts += "|" + NonProxyInfo

                                                         .defStringVal;

                                    }

                                    if (nphosts != null) {

                                        if (!nphosts.equals(nprop.hostsSource)) {

                                            nprop.pattern = toPattern(nphosts);

                                            nprop.hostsSource = nphosts;

                                        }

                                    }

                                    if (shouldNotUseProxyFor(nprop.pattern, urlhost)) {

                                        return null;

                                    }

                                }

                            }

                            // We got a host, let's check for port

                            pport = NetProperties.getInteger(props[i][j]+"Port", 0).intValue();

                            if (pport == 0 && j < (props[i].length - 1)) {

                                // Can't find a port with same prefix as Host

                                // AND it's not a SOCKS proxy

                                // Let's try the other prefixes for that proto

                                for (int k = 1; k < (props[i].length - 1); k++) {

                                    if ((k != j) && (pport == 0))

                                        pport = NetProperties.getInteger(props[i][k]+"Port", 0).intValue();

                                }

                            }

                            // Still couldn't find a port, let's use default

                            if (pport == 0) {

                                if (j == (props[i].length - 1)) // SOCKS

                                    pport = defaultPort("socket");

                                else

                                    pport = defaultPort(proto);

                            }

                            // We did find a proxy definition.

                            // Let's create the address, but don't resolve it

                            // as this will be done at connection time

                            saddr = InetSocketAddress.createUnresolved(phost, pport);

                            // Socks is *always* the last on the list.

                            if (j == (props[i].length - 1)) {

                                return new Proxy[] {SocksProxy.create(saddr, socksProxyVersion())};

                            }

                            return new Proxy[] {new Proxy(Proxy.Type.HTTP, saddr)};

                        }

                    }

                    return null;

                }});

        if (proxyArray != null) {

            // Remove duplicate entries, while preserving order.

            return Stream.of(proxyArray).distinct().collect(

                    collectingAndThen(toList(), Collections::unmodifiableList));

        }

        // If no specific proxy was found, return a standard list containing

        // only one NO_PROXY entry.

        return NO_PROXY_LIST;

    }

    public void connectFailed(URI uri, SocketAddress sa, IOException ioe) {

        if (uri == null || sa == null || ioe == null) {

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

        }

        // ignored

    }

    private int defaultPort(String protocol) {

        if ("http".equalsIgnoreCase(protocol)) {

            return 80;

        } else if ("https".equalsIgnoreCase(protocol)) {

            return 443;

        } else if ("ftp".equalsIgnoreCase(protocol)) {

            return 80;

        } else if ("socket".equalsIgnoreCase(protocol)) {

            return 1080;

        } else {

            return -1;

        }

    }

    private static native boolean init();

    private synchronized native Proxy[] getSystemProxies(String protocol, String host);

    /**

     * @return {@code true} if given this pattern for non-proxy hosts and this

     *         urlhost the proxy should NOT be used to access this urlhost

     */

    static boolean shouldNotUseProxyFor(Pattern pattern, String urlhost) {

        if (pattern == null || urlhost.isEmpty())

            return false;

        boolean matches = pattern.matcher(urlhost).matches();

        return matches;

    }

    /**

     * @param mask non-null mask

     * @return {@link java.util.regex.Pattern} corresponding to this mask

     *         or {@code null} in case mask should not match anything

     */

    static Pattern toPattern(String mask) {

        boolean disjunctionEmpty = true;

        StringJoiner joiner = new StringJoiner("|");

        for (String disjunct : mask.split("\\|")) {

            if (disjunct.isEmpty())

                continue;

            disjunctionEmpty = false;

            String regex = disjunctToRegex(disjunct.toLowerCase());

            joiner.add(regex);

        }

        return disjunctionEmpty ? null : Pattern.compile(joiner.toString());

    }

    /**

     * @param disjunct non-null mask disjunct

     * @return java regex string corresponding to this mask

     */

    static String disjunctToRegex(String disjunct) {

        String regex;

        if (disjunct.startsWith("*") && disjunct.endsWith("*")) {

            regex = ".*" + quote(disjunct.substring(1, disjunct.length() - 1)) + ".*";

        } else if (disjunct.startsWith("*")) {

            regex = ".*" + quote(disjunct.substring(1));

        } else if (disjunct.endsWith("*")) {

            regex = quote(disjunct.substring(0, disjunct.length() - 1)) + ".*";

        } else {

            regex = quote(disjunct);

        }

        return regex;

    }

}