/*

 * Copyright (c) 2010, 2013, 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 jdk.nashorn.internal.runtime;

import java.io.File;

import java.io.IOException;

import java.net.MalformedURLException;

import java.net.URL;

import java.net.URLClassLoader;

import java.security.CodeSource;

import java.security.Permission;

import java.security.PermissionCollection;

import java.security.Permissions;

import java.security.SecureClassLoader;

/**

 * Superclass for Nashorn class loader classes.

 */

abstract class NashornLoader extends SecureClassLoader {

    private static final String OBJECTS_PKG        = "jdk.nashorn.internal.objects";

    private static final String RUNTIME_PKG        = "jdk.nashorn.internal.runtime";

    private static final String RUNTIME_ARRAYS_PKG = "jdk.nashorn.internal.runtime.arrays";

    private static final String RUNTIME_LINKER_PKG = "jdk.nashorn.internal.runtime.linker";

    private static final String SCRIPTS_PKG        = "jdk.nashorn.internal.scripts";

    private static final Permission[] SCRIPT_PERMISSIONS;

    static {

        /*

         * Generated classes get access to runtime, runtime.linker, objects, scripts packages.

         * Note that the actual scripts can not access these because Java.type, Packages

         * prevent these restricted packages. And Java reflection and JSR292 access is prevented

         * for scripts. In other words, nashorn generated portions of script classes can access

         * classes in these implementation packages.

         */

        SCRIPT_PERMISSIONS = new Permission[] {

                new RuntimePermission("accessClassInPackage." + RUNTIME_PKG),

                new RuntimePermission("accessClassInPackage." + RUNTIME_LINKER_PKG),

                new RuntimePermission("accessClassInPackage." + OBJECTS_PKG),

                new RuntimePermission("accessClassInPackage." + SCRIPTS_PKG),

                new RuntimePermission("accessClassInPackage." + RUNTIME_ARRAYS_PKG)

        };

    }

    NashornLoader(final ClassLoader parent) {

        super(parent);

    }

    protected static void checkPackageAccess(final String name) {

        final int i = name.lastIndexOf('.');

        if (i != -1) {

            final SecurityManager sm = System.getSecurityManager();

            if (sm != null) {

                final String pkgName = name.substring(0, i);

                switch (pkgName) {

                    case RUNTIME_PKG:

                    case RUNTIME_ARRAYS_PKG:

                    case RUNTIME_LINKER_PKG:

                    case OBJECTS_PKG:

                    case SCRIPTS_PKG:

                        // allow it.

                        break;

                    default:

                        sm.checkPackageAccess(pkgName);

                }

            }

        }

    }

    @Override

    protected PermissionCollection getPermissions(final CodeSource codesource) {

        final Permissions permCollection = new Permissions();

        for (final Permission perm : SCRIPT_PERMISSIONS) {

            permCollection.add(perm);

        }

        return permCollection;

    }

    /**

     * Create a secure URL class loader for the given classpath

     * @param classPath classpath for the loader to search from

     * @return the class loader

     */

        final URL[] urls = pathToURLs(classPath);

        return URLClassLoader.newInstance(urls, parent);

    }

    /*

     * Utility method for converting a search path string to an array

     * of directory and JAR file URLs.

     *

     * @param path the search path string

     * @return the resulting array of directory and JAR file URLs

     */

    private static URL[] pathToURLs(final String path) {

        final String[] components = path.split(File.pathSeparator);

        URL[] urls = new URL[components.length];

        int count = 0;

        while(count < components.length) {

            final URL url = fileToURL(new File(components[count]));

            if (url != null) {

                urls[count++] = url;

            }

        }

        if (urls.length != count) {

            final URL[] tmp = new URL[count];

            System.arraycopy(urls, 0, tmp, 0, count);

            urls = tmp;

        }

        return urls;

    }

    /*

     * Returns the directory or JAR file URL corresponding to the specified

     * local file name.

     *

     * @param file the File object

     * @return the resulting directory or JAR file URL, or null if unknown

     */

    private static URL fileToURL(final File file) {

        String name;

        try {

            name = file.getCanonicalPath();

        } catch (final IOException e) {

            name = file.getAbsolutePath();

        }

        name = name.replace(File.separatorChar, '/');

        if (!name.startsWith("/")) {

            name = "/" + name;

        }

        // If the file does not exist, then assume that it's a directory

        if (!file.isFile()) {

            name += "/";

        }

        try {

            return new URL("file", "", name);

        } catch (final MalformedURLException e) {

            throw new IllegalArgumentException("file");

        }

    }

}