/*

 * Copyright (c) 1995, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.net.www.protocol.http;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.net.PasswordAuthentication;

import java.net.URL;

import java.util.HashMap;

import java.util.Objects;

import sun.net.www.HeaderParser;

/**

 * AuthenticationInfo: Encapsulate the information needed to

 * authenticate a user to a server.

 *

 * @author Jon Payne

 * @author Herb Jellinek

 * @author Bill Foote

 */

// REMIND:  It would be nice if this class understood about partial matching.

//      If you're authorized for foo.com, chances are high you're also

//      authorized for baz.foo.com.

// NB:  When this gets implemented, be careful about the uncaching

//      policy in HttpURLConnection.  A failure on baz.foo.com shouldn't

//      uncache foo.com!

public abstract class AuthenticationInfo extends AuthCacheValue implements Cloneable {

    static final long serialVersionUID = -2588378268010453259L;

    // Constants saying what kind of authroization this is.  This determines

    // the namespace in the hash table lookup.

    public static final char SERVER_AUTHENTICATION = 's';

    public static final char PROXY_AUTHENTICATION = 'p';

    /**

     * If true, then simultaneous authentication requests to the same realm/proxy

     * are serialized, in order to avoid a user having to type the same username/passwords

     * repeatedly, via the Authenticator. Default is false, which means that this

     * behavior is switched off.

     */

    static {

        serializeAuth = java.security.AccessController.doPrivileged(

            new sun.security.action.GetBooleanAction(

                "http.auth.serializeRequests")).booleanValue();

    }

    /* AuthCacheValue: */

    protected transient PasswordAuthentication pw;

    public PasswordAuthentication credentials() {

        return pw;

    }

    public AuthCacheValue.Type getAuthType() {

        return type == SERVER_AUTHENTICATION ?

            AuthCacheValue.Type.Server:

            AuthCacheValue.Type.Proxy;

    }

    AuthScheme getAuthScheme() {

        return authScheme;

    }

    public String getHost() {

        return host;

    }

    public int getPort() {

        return port;

    }

    public String getRealm() {

        return realm;

    }

    public String getPath() {

        return path;

    }

    public String getProtocolScheme() {

        return protocol;

    }

    /**

     * requests is used to ensure that interaction with the

     * Authenticator for a particular realm is single threaded.

     * ie. if multiple threads need to get credentials from the user

     * at the same time, then all but the first will block until

     * the first completes its authentication.

     */

    private static HashMap<String,Thread> requests = new HashMap<>();

    /* check if a request for this destination is in progress

     * return false immediately if not. Otherwise block until

     * request is finished and return true

     */

    private static boolean requestIsInProgress (String key) {

        if (!serializeAuth) {

            /* behavior is disabled. Revert to concurrent requests */

            return false;

        }

        synchronized (requests) {

            Thread t, c;

            c = Thread.currentThread();

            if ((t = requests.get(key)) == null) {

                requests.put (key, c);

                return false;

            }

            if (t == c) {

                return false;

            }

            while (requests.containsKey(key)) {

                try {

                    requests.wait ();

                } catch (InterruptedException e) {}

            }

        }

        /* entry may be in cache now. */

        return true;

    }

    /* signal completion of an authentication (whether it succeeded or not)

     * so that other threads can continue.

     */

    private static void requestCompleted (String key) {

        synchronized (requests) {

            Thread thread = requests.get(key);

            if (thread != null && thread == Thread.currentThread()) {

                boolean waspresent = requests.remove(key) != null;

                assert waspresent;

            }

            requests.notifyAll();

        }

    }

    //public String toString () {

        //return ("{"+type+":"+authScheme+":"+protocol+":"+host+":"+port+":"+realm+":"+path+"}");

    //}

    // REMIND:  This cache just grows forever.  We should put in a bounded

    //          cache, or maybe something using WeakRef's.

    /** The type (server/proxy) of authentication this is.  Used for key lookup */

    char type;

    /** The authentication scheme (basic/digest). Also used for key lookup */

    AuthScheme authScheme;

    /** The protocol/scheme (i.e. http or https ). Need to keep the caches

     *  logically separate for the two protocols. This field is only used

     *  when constructed with a URL (the normal case for server authentication)

     *  For proxy authentication the protocol is not relevant.

     */

    String protocol;

    /** The host we're authenticating against. */

    String host;

    /** The port on the host we're authenticating against. */

    int port;

    /** The realm we're authenticating against. */

    String realm;

    /** The shortest path from the URL we authenticated against. */

    String path;

    /**

     * A key identifying the authenticator from which the credentials

     * were obtained.

     * {@link AuthenticatorKeys#DEFAULT} identifies the {@linkplain

     * java.net.Authenticator#setDefault(java.net.Authenticator) default}

     * authenticator.

     */

     String authenticatorKey;

    /** Use this constructor only for proxy entries */

    public AuthenticationInfo(char type, AuthScheme authScheme, String host,

                              int port, String realm, String authenticatorKey) {

        this.type = type;

        this.authScheme = authScheme;

        this.protocol = "";

        this.host = host.toLowerCase();

        this.port = port;

        this.realm = realm;

        this.path = null;

        this.authenticatorKey = Objects.requireNonNull(authenticatorKey);

    }

    public Object clone() {

        try {

            return super.clone ();

        } catch (CloneNotSupportedException e) {

            // Cannot happen because Cloneable implemented by AuthenticationInfo

            return null;

        }

    }

    /*

     * Constructor used to limit the authorization to the path within

     * the URL. Use this constructor for origin server entries.

     */

    public AuthenticationInfo(char type, AuthScheme authScheme, URL url, String realm,

                              String authenticatorKey) {

        this.type = type;

        this.authScheme = authScheme;

        this.protocol = url.getProtocol().toLowerCase();

        this.host = url.getHost().toLowerCase();

        this.port = url.getPort();

        if (this.port == -1) {

            this.port = url.getDefaultPort();

        }

        this.realm = realm;

        String urlPath = url.getPath();

        if (urlPath.length() == 0)

            this.path = urlPath;

        else {

            this.path = reducePath (urlPath);

        }

        this.authenticatorKey = Objects.requireNonNull(authenticatorKey);

    }

    /**

     * The {@linkplain java.net.Authenticator#getKey(java.net.Authenticator) key}

     * of the authenticator that was used to obtain the credentials.

     * @return The authenticator's key.

     */

    public final String getAuthenticatorKey() {

        return authenticatorKey;

    }

    /*

     * reduce the path to the root of where we think the

     * authorization begins. This could get shorter as

     * the url is traversed up following a successful challenge.

     */

    static String reducePath (String urlPath) {

        int sepIndex = urlPath.lastIndexOf('/');

        int targetSuffixIndex = urlPath.lastIndexOf('.');

        if (sepIndex != -1)

            if (sepIndex < targetSuffixIndex)

                return urlPath.substring(0, sepIndex+1);

            else

                return urlPath;

        else

            return urlPath;

    }

    /**

     * Returns info for the URL, for an HTTP server auth.  Used when we

     * don't yet know the realm

     * (i.e. when we're preemptively setting the auth).

     */

    static AuthenticationInfo getServerAuth(URL url, String authenticatorKey) {

        int port = url.getPort();

        if (port == -1) {

            port = url.getDefaultPort();

        }

        String key = SERVER_AUTHENTICATION + ":" + url.getProtocol().toLowerCase()

                + ":" + url.getHost().toLowerCase() + ":" + port

                + ";auth=" + authenticatorKey;

        return getAuth(key, url);

    }

    /**

     * Returns info for the URL, for an HTTP server auth.  Used when we

     * do know the realm (i.e. when we're responding to a challenge).

     * In this case we do not use the path because the protection space

     * is identified by the host:port:realm only

     */

    static String getServerAuthKey(URL url, String realm, AuthScheme scheme,

                                   String authenticatorKey) {

        int port = url.getPort();

        if (port == -1) {

            port = url.getDefaultPort();

        }

        String key = SERVER_AUTHENTICATION + ":" + scheme + ":"

                     + url.getProtocol().toLowerCase()

                     + ":" + url.getHost().toLowerCase()

                     + ":" + port + ":" + realm

                     + ";auth=" + authenticatorKey;

        return key;

    }

    static AuthenticationInfo getServerAuth(String key) {

        AuthenticationInfo cached = getAuth(key, null);

        if ((cached == null) && requestIsInProgress (key)) {

            /* check the cache again, it might contain an entry */

            cached = getAuth(key, null);

        }

        return cached;

    }

    /**

     * Return the AuthenticationInfo object from the cache if it's path is

     * a substring of the supplied URLs path.

     */

    static AuthenticationInfo getAuth(String key, URL url) {

        if (url == null) {

            return (AuthenticationInfo)cache.get (key, null);

        } else {

            return (AuthenticationInfo)cache.get (key, url.getPath());

        }

    }

    /**

     * Returns a firewall authentication, for the given host/port.  Used

     * for preemptive header-setting. Note, the protocol field is always

     * blank for proxies.

     */

    static AuthenticationInfo getProxyAuth(String host, int port,

                                           String authenticatorKey) {

        String key = PROXY_AUTHENTICATION + "::" + host.toLowerCase() + ":" + port

                     + ";auth=" + authenticatorKey;

        AuthenticationInfo result = (AuthenticationInfo) cache.get(key, null);

        return result;

    }

    /**

     * Returns a firewall authentication, for the given host/port and realm.

     * Used in response to a challenge. Note, the protocol field is always

     * blank for proxies.

     */

    static String getProxyAuthKey(String host, int port, String realm,

                                  AuthScheme scheme, String authenticatorKey) {

        String key = PROXY_AUTHENTICATION + ":" + scheme

                        + "::" + host.toLowerCase()

                        + ":" + port + ":" + realm

                        + ";auth=" + authenticatorKey;

        return key;

    }

    static AuthenticationInfo getProxyAuth(String key) {

        AuthenticationInfo cached = (AuthenticationInfo) cache.get(key, null);

        if ((cached == null) && requestIsInProgress (key)) {

            /* check the cache again, it might contain an entry */

            cached = (AuthenticationInfo) cache.get(key, null);

        }

        return cached;

    }

    /**

     * Add this authentication to the cache

     */

    void addToCache() {

        String key = cacheKey(true);

        }

        endAuthRequest(key);

    }

    static void endAuthRequest (String key) {

        if (!serializeAuth) {

            return;

        }

        synchronized (requests) {

            requestCompleted(key);

        }

    }

    /**

     * Remove this authentication from the cache

     */

    void removeFromCache() {

        cache.remove(cacheKey(true), this);

        if (supportsPreemptiveAuthorization()) {

            cache.remove(cacheKey(false), this);

        }

    }

    /**

     * @return true if this authentication supports preemptive authorization

     */

    public abstract boolean supportsPreemptiveAuthorization();

    /**

     * @return the name of the HTTP header this authentication wants set.

     *          This is used for preemptive authorization.

     */

    public String getHeaderName() {

        if (type == SERVER_AUTHENTICATION) {

            return "Authorization";

        } else {

            return "Proxy-authorization";

        }

    }

    /**

     * Calculates and returns the authentication header value based

     * on the stored authentication parameters. If the calculation does not depend

     * on the URL or the request method then these parameters are ignored.

     * @param url The URL

     * @param method The request method

     * @return the value of the HTTP header this authentication wants set.

     *          Used for preemptive authorization.

     */

    public abstract String getHeaderValue(URL url, String method);

    /**

     * Set header(s) on the given connection.  Subclasses must override

     * This will only be called for

     * definitive (i.e. non-preemptive) authorization.

     * @param conn The connection to apply the header(s) to

     * @param p A source of header values for this connection, if needed.

     * @param raw The raw header field (if needed)

     * @return true if all goes well, false if no headers were set.

     */

    public abstract boolean setHeaders(HttpURLConnection conn, HeaderParser p, String raw);

    /**

     * Check if the header indicates that the current auth. parameters are stale.

     * If so, then replace the relevant field with the new value

     * and return true. Otherwise return false.

     * returning true means the request can be retried with the same userid/password

     * returning false means we have to go back to the user to ask for a new

     * username password.

     */

    public abstract boolean isAuthorizationStale (String header);

    /**

     * Give a key for hash table lookups.

     * @param includeRealm if you want the realm considered.  Preemptively

     *          setting an authorization is done before the realm is known.

     */

    String cacheKey(boolean includeRealm) {

        // This must be kept in sync with the getXXXAuth() methods in this

        // class.

        String authenticatorKey = getAuthenticatorKey();

        if (includeRealm) {

            return type + ":" + authScheme + ":" + protocol + ":"

                        + host + ":" + port + ":" + realm

                     + ";auth=" + authenticatorKey;

        } else {

            return type + ":" + protocol + ":" + host + ":" + port

                     + ";auth=" + authenticatorKey;

        }

    }

    String s1, s2;  /* used for serialization of pw */

    private synchronized void readObject(ObjectInputStream s)

        throws IOException, ClassNotFoundException

    {

        s.defaultReadObject ();

        pw = new PasswordAuthentication (s1, s2.toCharArray());

        s1 = null; s2= null;

        if (authenticatorKey == null) {

            authenticatorKey = AuthenticatorKeys.DEFAULT;

        }

    }

    private synchronized void writeObject(java.io.ObjectOutputStream s)

        throws IOException

    {

        Objects.requireNonNull(authenticatorKey);

        s1 = pw.getUserName();

        s2 = new String (pw.getPassword());

        s.defaultWriteObject ();

    }

}