/*

 * Copyright (c) 2019, 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.security.util;

import java.io.File;

import java.io.FilePermission;

import java.io.IOException;

import java.net.URL;

import java.security.CodeSource;

import java.security.Permission;

import java.security.PermissionCollection;

import java.util.Enumeration;

/**

 * This {@code PermissionCollection} implementation delegates to another

 * {@code PermissionCollection}, taking care to lazily add the permission needed

 * to read from the given {@code CodeSource} at first use, i.e., when either of

 * {@link #elements}, {@link #implies} or {@link #toString} is called, or when

 * the collection is serialized.

 */

public final class LazyCodeSourcePermissionCollection

        extends PermissionCollection

{

    @java.io.Serial

    private static final long serialVersionUID = -6727011328946861783L;

    private final PermissionCollection perms;

    private final CodeSource cs;

    private volatile boolean permissionAdded;

    public LazyCodeSourcePermissionCollection(PermissionCollection perms,

                                              CodeSource cs) {

        this.perms = perms;

        this.cs = cs;

    }

    private void ensureAdded() {

        if (!permissionAdded) {

            synchronized(perms) {

                if (permissionAdded)

                    return;

                // open connection to determine the permission needed

                URL location = cs.getLocation();

                if (location != null) {

                    try {

                        Permission p = location.openConnection().getPermission();

                        if (p != null) {

                            // for directories then need recursive access

                            if (p instanceof FilePermission) {

                                String path = p.getName();

                                if (path.endsWith(File.separator)) {

                                    path += "-";

                                    p = new FilePermission(path,

                                            SecurityConstants.FILE_READ_ACTION);

                                }

                            }

                            perms.add(p);

                        }

                    } catch (IOException ioe) {

                    }

                }

                if (isReadOnly()) {

                    perms.setReadOnly();

                }

                permissionAdded = true;

            }

        }

    }

    @Override

    public void add(Permission permission) {

        if (isReadOnly())

            throw new SecurityException(

                    "attempt to add a Permission to a readonly PermissionCollection");

        perms.add(permission);

    }

    @Override

    public boolean implies(Permission permission) {

        ensureAdded();

        return perms.implies(permission);

    }

    @Override

    public Enumeration<Permission> elements() {

        ensureAdded();

        return perms.elements();

    }

    @Override

    public String toString() {

        ensureAdded();

        return perms.toString();

    }

    /**

     * On serialization, initialize and replace with the underlying

     * permissions. This removes the laziness on deserialization.

     */

    @java.io.Serial

    private Object writeReplace() {

        ensureAdded();

        return perms;

    }

}