GSSManagerFactory.java

/*
 * Copyright (C) 2014 Laurent Goujon <lgoujon@twitter.com> and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.eclipse.jgit.util;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.net.URL;

import org.ietf.jgss.GSSManager;

/**
 * Factory to detect which GSSManager implementation should be used.
 *
 * @since 3.4
 */
public abstract class GSSManagerFactory {
    /**
     * Auto-detects the GSSManager factory to use based on system.
     *
     * @return detected GSSManager factory
     */
    public static GSSManagerFactory detect() {
        return (SunGSSManagerFactory.isSupported()) ? new SunGSSManagerFactory()
                : new DefaultGSSManagerFactory();
    }

    /**
     * Returns a GSS Manager instance for the provided url
     *
     * @param url
     *            the repository url
     * @return a GSSManager instance
     */
    public abstract GSSManager newInstance(URL url);

    /**
     * DefaultGSSManagerFactory uses @link {@link GSSManager#getInstance()} but
     * you might need to set
     * <code>javax.security.auth.useSubjectCredsOnly</code> system property to
     * <code>false</code> for authentication to work.
     */
    private static class DefaultGSSManagerFactory extends GSSManagerFactory {
        private static final GSSManager INSTANCE = GSSManager.getInstance();

        @Override
        public GSSManager newInstance(URL url) {
            return INSTANCE;
        }
    }

    private static class SunGSSManagerFactory extends GSSManagerFactory {
        private static boolean IS_SUPPORTED;
        private static Constructor<?> HTTP_CALLER_INFO_CONSTRUCTOR;
        private static Constructor<?> HTTP_CALLER_CONSTRUCTOR;

        private static Constructor<?> GSS_MANAGER_IMPL_CONSTRUCTOR;

        static {
            try {
                init();
                IS_SUPPORTED = true;
            } catch (Exception e) {
                IS_SUPPORTED = false;
            }
        }

        private static void init() throws ClassNotFoundException,
                NoSuchMethodException {
            Class<?> httpCallerInfoClazz = Class
                    .forName("sun.net.www.protocol.http.HttpCallerInfo"); //$NON-NLS-1$
            HTTP_CALLER_INFO_CONSTRUCTOR = httpCallerInfoClazz
                    .getConstructor(URL.class);

            Class<?> httpCallerClazz = Class
                    .forName("sun.security.jgss.HttpCaller"); //$NON-NLS-1$
            HTTP_CALLER_CONSTRUCTOR = httpCallerClazz
                    .getConstructor(httpCallerInfoClazz);

            Class<?> gssCallerClazz = Class
                    .forName("sun.security.jgss.GSSCaller"); //$NON-NLS-1$
            Class<?> gssManagerImplClazz = Class
                    .forName("sun.security.jgss.GSSManagerImpl"); //$NON-NLS-1$
            GSS_MANAGER_IMPL_CONSTRUCTOR = gssManagerImplClazz
                    .getConstructor(gssCallerClazz);

        }

        /**
         * Detects if SunGSSManagerProvider is supported by the system
         *
         * @return true if it is supported
         */
        public static boolean isSupported() {
            return IS_SUPPORTED;
        }

        @Override
        public GSSManager newInstance(URL url) {
            try {
                Object httpCallerInfo = HTTP_CALLER_INFO_CONSTRUCTOR
                        .newInstance(url);
                Object httpCaller = HTTP_CALLER_CONSTRUCTOR
                        .newInstance(httpCallerInfo);

                return (GSSManager) GSS_MANAGER_IMPL_CONSTRUCTOR
                        .newInstance(httpCaller);
            } catch (InstantiationException | IllegalAccessException
                    | IllegalArgumentException | InvocationTargetException e) {
                throw new Error(e);
            }
        }
    }
}