/*

 * Copyright (c) 2000, 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 com.sun.rmi.rmid;

import java.security.*;

import java.io.*;

import java.util.*;

/**

 * The ExecOptionPermission class represents permission for rmid to use

 * a specific command-line option when launching an activation group.

 * <P>

 *

 * @author Ann Wollrath

 *

 * @serial exclude

 */

public final class ExecOptionPermission extends Permission

{

    /**

     * does this permission have a wildcard at the end?

     */

    private transient boolean wildcard;

    /**

     * the name without the wildcard on the end

     */

    private transient String name;

    /**

     * UID for serialization

     */

    private static final long serialVersionUID = 5842294756823092756L;

    public ExecOptionPermission(String name) {

        super(name);

        init(name);

    }

    public ExecOptionPermission(String name, String actions) {

        this(name);

    }

    /**

     * Checks if the specified permission is "implied" by

     * this object.

     * <P>

     * More specifically, this method returns true if:<p>

     * <ul>

     * <li> <i>p</i>'s class is the same as this object's class, and<p>

     * <li> <i>p</i>'s name equals or (in the case of wildcards)

     *      is implied by this object's

     *      name. For example, "a.b.*" implies "a.b.c", and

     *      "a.b=*" implies "a.b=c"

     * </ul>

     *

     * @param p the permission to check against.

     *

     * @return true if the passed permission is equal to or

     * implied by this permission, false otherwise.

     */

    public boolean implies(Permission p) {

        if (!(p instanceof ExecOptionPermission))

            return false;

        ExecOptionPermission that = (ExecOptionPermission) p;

        if (this.wildcard) {

            if (that.wildcard) {

                // one wildcard can imply another

                return that.name.startsWith(name);

            } else {

                // make sure p.name is longer so a.b.* doesn't imply a.b

                return (that.name.length() > this.name.length()) &&

                    that.name.startsWith(this.name);

            }

        } else {

            if (that.wildcard) {

                // a non-wildcard can't imply a wildcard

                return false;

            } else {

                return this.name.equals(that.name);

            }

        }

    }

    /**

     * Checks two ExecOptionPermission objects for equality.

     * Checks that <i>obj</i>'s class is the same as this object's class

     * and has the same name as this object.

     * <P>

     * @param obj the object we are testing for equality with this object.

     * @return true if <i>obj</i> is an ExecOptionPermission, and has the same

     * name as this ExecOptionPermission object, false otherwise.

     */

    public boolean equals(Object obj) {

        if (obj == this)

            return true;

        if ((obj == null) || (obj.getClass() != getClass()))

            return false;

        ExecOptionPermission that = (ExecOptionPermission) obj;

        return this.getName().equals(that.getName());

    }

    /**

     * Returns the hash code value for this object.

     * The hash code used is the hash code of the name, that is,

     * <code>getName().hashCode()</code>, where <code>getName</code> is

     * from the Permission superclass.

     *

     * @return a hash code value for this object.

     */

    public int hashCode() {

        return this.getName().hashCode();

    }

    /**

     * Returns the canonical string representation of the actions.

     *

     * @return the canonical string representation of the actions.

     */

    public String getActions() {

        return "";

    }

    /**

     * Returns a new PermissionCollection object for storing

     * ExecOptionPermission objects.

     * <p>

     * A ExecOptionPermissionCollection stores a collection of

     * ExecOptionPermission permissions.

     *

     * <p>ExecOptionPermission objects must be stored in a manner that allows

     * them to be inserted in any order, but that also enables the

     * PermissionCollection <code>implies</code> method

     * to be implemented in an efficient (and consistent) manner.

     *

     * @return a new PermissionCollection object suitable for

     * storing ExecOptionPermissions.

     */

    public PermissionCollection newPermissionCollection() {

        return new ExecOptionPermissionCollection();

    }

    /**

     * readObject is called to restore the state of the ExecOptionPermission

     * from a stream.

     */

    private synchronized void readObject(java.io.ObjectInputStream s)

         throws IOException, ClassNotFoundException

    {

        s.defaultReadObject();

        // init is called to initialize the rest of the values.

        init(getName());

    }

    /**

     * Initialize a ExecOptionPermission object. Common to all constructors.

     * Also called during de-serialization.

     */

    private void init(String name)

    {

        if (name == null)

            throw new NullPointerException("name can't be null");

        if (name.equals("")) {

            throw new IllegalArgumentException("name can't be empty");

        }

        if (name.endsWith(".*") || name.endsWith("=*") || name.equals("*")) {

            wildcard = true;

            if (name.length() == 1) {

                this.name = "";

            } else {

                this.name = name.substring(0, name.length()-1);

            }

        } else {

            this.name = name;

        }

    }

    /**

     * A ExecOptionPermissionCollection stores a collection

     * of ExecOptionPermission permissions. ExecOptionPermission objects

     * must be stored in a manner that allows them to be inserted in any

     * order, but enable the implies function to evaluate the implies

     * method in an efficient (and consistent) manner.

     *

     * A ExecOptionPermissionCollection handles comparing a permission like

     * "a.b.c.d.e" * with a Permission such as "a.b.*", or "*".

     *

     * @serial include

     */

    private static class ExecOptionPermissionCollection

        extends PermissionCollection

        implements java.io.Serializable

    {

        private Hashtable permissions;

        private boolean all_allowed; // true if "*" is in the collection

        private static final long serialVersionUID = -1242475729790124375L;

        /**

         * Create an empty ExecOptionPermissionCollection.

         */

        public ExecOptionPermissionCollection() {

            permissions = new Hashtable(11);

            all_allowed = false;

        }

        /**

         * Adds a permission to the collection. The key for the hash is

         * permission.name.

         *

         * @param permission the Permission object to add.

         *

         * @exception IllegalArgumentException - if the permission is not a

         *                                       ExecOptionPermission

         *

         * @exception SecurityException - if this ExecOptionPermissionCollection

         *                                object has been marked readonly

         */

        public void add(Permission permission)

        {

            if (! (permission instanceof ExecOptionPermission))

                throw new IllegalArgumentException("invalid permission: "+

                                                   permission);

            if (isReadOnly())

                throw new SecurityException("attempt to add a Permission to a readonly PermissionCollection");

            ExecOptionPermission p = (ExecOptionPermission) permission;

            permissions.put(p.getName(), permission);

            if (!all_allowed) {

                if (p.getName().equals("*"))

                    all_allowed = true;

            }

        }

        /**

         * Check and see if this set of permissions implies the permissions

         * expressed in "permission".

         *

         * @param p the Permission object to compare

         *

         * @return true if "permission" is a proper subset of a permission in

         * the set, false if not.

         */

        public boolean implies(Permission permission)

        {

            if (! (permission instanceof ExecOptionPermission))

                return false;

            ExecOptionPermission p = (ExecOptionPermission) permission;

            // short circuit if the "*" Permission was added

            if (all_allowed)

                return true;

            // strategy:

            // Check for full match first. Then work our way up the

            // name looking for matches on a.b.*

            String pname = p.getName();

            Permission x = (Permission) permissions.get(pname);

            if (x != null)

                // we have a direct hit!

                return x.implies(permission);

            // work our way up the tree...

            int last, offset;

            offset = pname.length() - 1;

            while ((last = pname.lastIndexOf(".", offset)) != -1) {

                pname = pname.substring(0, last+1) + "*";

                x = (Permission) permissions.get(pname);

                if (x != null) {

                    return x.implies(permission);

                }

                offset = last - 1;

            }

            // check for "=*" wildcard match

            pname = p.getName();

            offset = pname.length() - 1;

            while ((last = pname.lastIndexOf("=", offset)) != -1) {

                pname = pname.substring(0, last+1) + "*";

                x = (Permission) permissions.get(pname);

                if (x != null) {

                    return x.implies(permission);

                }

                offset = last - 1;

            }

            // we don't have to check for "*" as it was already checked

            // at the top (all_allowed), so we just return false

            return false;

        }

        /**

         * Returns an enumeration of all the ExecOptionPermission objects in the

         * container.

         *

         * @return an enumeration of all the ExecOptionPermission objects.

         */

        public Enumeration elements()

        {

            return permissions.elements();

        }

    }

}