/*

 * Copyright 1997-2007 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package java.security;

import java.security.*;

import java.util.Enumeration;

import java.util.Map;

import java.util.HashMap;

import java.util.Hashtable;

import java.util.Collections;

import java.io.ObjectStreamField;

import java.io.ObjectOutputStream;

import java.io.ObjectInputStream;

import java.io.IOException;

/**

 * The BasicPermission class extends the Permission class, and

 * can be used as the base class for permissions that want to

 * follow the same naming convention as BasicPermission.

 * <P>

 * The name for a BasicPermission is the name of the given permission

 * (for example, "exit",

 * "setFactory", "print.queueJob", etc). The naming

 * convention follows the  hierarchical property naming convention.

 * An asterisk may appear by itself, or if immediately preceded by a "."

 * may appear at the end of the name, to signify a wildcard match.

 * For example, "*" and "java.*" are valid, while "*java", "a*b",

 * and "java*" are not valid.

 * <P>

 * The action string (inherited from Permission) is unused.

 * Thus, BasicPermission is commonly used as the base class for

 * "named" permissions

 * (ones that contain a name but no actions list; you either have the

 * named permission or you don't.)

 * Subclasses may implement actions on top of BasicPermission,

 * if desired.

 * <p>

 * <P>

 * @see java.security.Permission

 * @see java.security.Permissions

 * @see java.security.PermissionCollection

 * @see java.lang.SecurityManager

 *

 * @author Marianne Mueller

 * @author Roland Schemers

 */

public abstract class BasicPermission extends Permission

implements java.io.Serializable

{

    private static final long serialVersionUID = 6279438298436773498L;

    // does this permission have a wildcard at the end?

    private transient boolean wildcard;

    // the name without the wildcard on the end

    private transient String path;

    // is this permission the old-style exitVM permission (pre JDK 1.6)?

    private transient boolean exitVM;

    /**

     * initialize a BasicPermission object. Common to all constructors.

     *

     */

    private void init(String name)

    {

        if (name == null)

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

        int len = name.length();

        if (len == 0) {

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

        }

        char last = name.charAt(len - 1);

        // Is wildcard or ends with ".*"?

        if (last == '*' && (len == 1 || name.charAt(len - 2) == '.')) {

            wildcard = true;

            if (len == 1) {

                path = "";

            } else {

                path = name.substring(0, len - 1);

            }

        } else {

            if (name.equals("exitVM")) {

                wildcard = true;

                path = "exitVM.";

                exitVM = true;

            } else {

                path = name;

            }

        }

    }

    /**

     * Creates a new BasicPermission with the specified name.

     * Name is the symbolic name of the permission, such as

     * "setFactory",

     * "print.queueJob", or "topLevelWindow", etc.

     *

     * @param name the name of the BasicPermission.

     *

     * @throws NullPointerException if <code>name</code> is <code>null</code>.

     * @throws IllegalArgumentException if <code>name</code> is empty.

     */

    public BasicPermission(String name)

    {

        super(name);

        init(name);

    }

    /**

     * Creates a new BasicPermission object with the specified name.

     * The name is the symbolic name of the BasicPermission, and the

     * actions String is currently unused.

     *

     * @param name the name of the BasicPermission.

     * @param actions ignored.

     *

     * @throws NullPointerException if <code>name</code> is <code>null</code>.

     * @throws IllegalArgumentException if <code>name</code> is empty.

     */

    public BasicPermission(String name, String actions)

    {

        super(name);

        init(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".

     * </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 == null) || (p.getClass() != getClass()))

            return false;

        BasicPermission that = (BasicPermission) p;

        if (this.wildcard) {

            if (that.wildcard) {

                // one wildcard can imply another

                return that.path.startsWith(path);

            } else {

                // make sure ap.path is longer so a.b.* doesn't imply a.b

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

                    that.path.startsWith(this.path);

            }

        } else {

            if (that.wildcard) {

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

                return false;

            }

            else {

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

            }

        }

    }

    /**

     * Checks two BasicPermission 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.

     */

    public boolean equals(Object obj) {

        if (obj == this)

            return true;

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

            return false;

        BasicPermission bp = (BasicPermission) obj;

        return getName().equals(bp.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,

     * which currently is the empty string "", since there are no actions for

     * a BasicPermission.

     *

     * @return the empty string "".

     */

    public String getActions()

    {

        return "";

    }

    /**

     * Returns a new PermissionCollection object for storing BasicPermission

     * objects.

     *

     * <p>BasicPermission 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 BasicPermissions.

     */

    public PermissionCollection newPermissionCollection() {

        return new BasicPermissionCollection(this.getClass());

    }

    /**

     * readObject is called to restore the state of the BasicPermission from

     * a stream.

     */

    private void readObject(ObjectInputStream s)

         throws IOException, ClassNotFoundException

    {

        s.defaultReadObject();

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

        init(getName());

    }

    /**

     * Returns the canonical name of this BasicPermission.

     * All internal invocations of getName should invoke this method, so

     * that the pre-JDK 1.6 "exitVM" and current "exitVM.*" permission are

     * equivalent in equals/hashCode methods.

     *

     * @return the canonical name of this BasicPermission.

     */

    final String getCanonicalName() {

        return exitVM ? "exitVM.*" : getName();

    }

}

/**

 * A BasicPermissionCollection stores a collection

 * of BasicPermission permissions. BasicPermission 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 BasicPermissionCollection handles comparing a permission like "a.b.c.d.e"

 * with a Permission such as "a.b.*", or "*".

 *

 * @see java.security.Permission

 * @see java.security.Permissions

 * @see java.security.PermissionsImpl

 *

 *

 * @author Roland Schemers

 *

 * @serial include

 */

final class BasicPermissionCollection

extends PermissionCollection

implements java.io.Serializable

{

    private static final long serialVersionUID = 739301742472979399L;

    /**

      * Key is name, value is permission. All permission objects in

      * collection must be of the same type.

      * Not serialized; see serialization section at end of class.

      */

    private transient Map<String, Permission> perms;

    /**

     * This is set to <code>true</code> if this BasicPermissionCollection

     * contains a BasicPermission with '*' as its permission name.

     *

     * @see #serialPersistentFields

     */

    private boolean all_allowed;

    /**

     * The class to which all BasicPermissions in this

     * BasicPermissionCollection belongs.

     *

     * @see #serialPersistentFields

     */

    private Class permClass;

    /**

     * Create an empty BasicPermissionCollection object.

     *

     */

    public BasicPermissionCollection(Class clazz) {

        perms = new HashMap<String, Permission>(11);

        all_allowed = false;

        permClass = clazz;

    }

    /**

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

     * permission.path.

     *

     * @param permission the Permission object to add.

     *

     * @exception IllegalArgumentException - if the permission is not a

     *                                       BasicPermission, or if

     *                                       the permission is not of the

     *                                       same Class as the other

     *                                       permissions in this collection.

     *

     * @exception SecurityException - if this BasicPermissionCollection object

     *                                has been marked readonly

     */

    public void add(Permission permission)

    {

        if (! (permission instanceof BasicPermission))

            throw new IllegalArgumentException("invalid permission: "+

                                               permission);

        if (isReadOnly())

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

        BasicPermission bp = (BasicPermission) permission;

        // make sure we only add new BasicPermissions of the same class

        // Also check null for compatibility with deserialized form from

        // previous versions.

        if (permClass == null) {

            // adding first permission

            permClass = bp.getClass();

        } else {

            if (bp.getClass() != permClass)

                throw new IllegalArgumentException("invalid permission: " +

                                                permission);

        }

        synchronized (this) {

            perms.put(bp.getCanonicalName(), permission);

        }

        // No sync on all_allowed; staleness OK

        if (!all_allowed) {

            if (bp.getCanonicalName().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 BasicPermission))

                return false;

        BasicPermission bp = (BasicPermission) permission;

        // random subclasses of BasicPermission do not imply each other

        if (bp.getClass() != permClass)

            return false;

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

        if (all_allowed)

            return true;

        // strategy:

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

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

        String path = bp.getCanonicalName();

        //System.out.println("check "+path);

        Permission x;

        synchronized (this) {

            x = perms.get(path);

        }

        if (x != null) {

            // we have a direct hit!

            return x.implies(permission);

        }

        // work our way up the tree...

        int last, offset;

        offset = path.length()-1;

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

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

            //System.out.println("check "+path);

            synchronized (this) {

                x = perms.get(path);

            }

            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 BasicPermission objects in the

     * container.

     *

     * @return an enumeration of all the BasicPermission objects.

     */

    public Enumeration<Permission> elements() {

        // Convert Iterator of Map values into an Enumeration

        synchronized (this) {

            return Collections.enumeration(perms.values());

        }

    }

    // Need to maintain serialization interoperability with earlier releases,

    // which had the serializable field:

    //

    // @serial the Hashtable is indexed by the BasicPermission name

    //

    // private Hashtable permissions;

    /**

     * @serialField permissions java.util.Hashtable

     *    The BasicPermissions in this BasicPermissionCollection.

     *    All BasicPermissions in the collection must belong to the same class.

     *    The Hashtable is indexed by the BasicPermission name; the value

     *    of the Hashtable entry is the permission.

     * @serialField all_allowed boolean

     *   This is set to <code>true</code> if this BasicPermissionCollection

     *   contains a BasicPermission with '*' as its permission name.

     * @serialField permClass java.lang.Class

     *   The class to which all BasicPermissions in this

     *   BasicPermissionCollection belongs.

     */

    private static final ObjectStreamField[] serialPersistentFields = {

        new ObjectStreamField("permissions", Hashtable.class),

        new ObjectStreamField("all_allowed", Boolean.TYPE),

        new ObjectStreamField("permClass", Class.class),

    };

    /**

     * @serialData Default fields.

     */

    /*

     * Writes the contents of the perms field out as a Hashtable for

     * serialization compatibility with earlier releases. all_allowed

     * and permClass unchanged.

     */

    private void writeObject(ObjectOutputStream out) throws IOException {

        // Don't call out.defaultWriteObject()

        // Copy perms into a Hashtable

        Hashtable<String, Permission> permissions =

                new Hashtable<String, Permission>(perms.size()*2);

        synchronized (this) {

            permissions.putAll(perms);

        }

        // Write out serializable fields

        ObjectOutputStream.PutField pfields = out.putFields();

        pfields.put("all_allowed", all_allowed);

        pfields.put("permissions", permissions);

        pfields.put("permClass", permClass);