/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package org.apache.batik.bridge;

import org.apache.batik.util.ParsedURL;

/**
 * This implementation of the <code>ScriptSecurity</code> interface only
 * allows scripts embeded in the document, i.e., scripts whith either
 * the same URL as the document (as for event attributes) or scripts
 * embeded with the data protocol.
 *
 * @author <a href="mailto:vhardy@apache.org">Vincent Hardy</a>
 * @version $Id$
 */
public class EmbededScriptSecurity implements ScriptSecurity {

    public static final String DATA_PROTOCOL = "data";

    /**
     * Message when trying to load a script file and the Document
     * does not have a URL
     */
    public static final String ERROR_CANNOT_ACCESS_DOCUMENT_URL
        = "DefaultScriptSecurity.error.cannot.access.document.url";

    /**
     * Message when trying to load a script that is not embeded
     * in the document.
     */
    public static final String ERROR_SCRIPT_NOT_EMBEDED
        = "EmbededScriptSecurity.error.script.not.embeded";

    /**
     * The exception is built in the constructor and thrown if 
     * not null and the checkLoadScript method is called.
     */
    protected SecurityException se;

    /**
     * Controls whether the script should be loaded or not.
     *
     * @throws SecurityException if the script should not be loaded.
     */
    public void checkLoadScript(){
        if (se != null) {
            throw se;
        }
    }

    /**
     * @param scriptType type of script, as found in the 
     *        type attribute of the &lt;script&gt; element.
     * @param scriptURL url for the script, as defined in
     *        the script's xlink:href attribute. If that
     *        attribute was empty, then this parameter should
     *        be null
     * @param docURL url for the document into which the 
     *        script was found.
     */
    public EmbededScriptSecurity(String scriptType,
                                 ParsedURL scriptURL,
                                 ParsedURL docURL){
        // Make sure that the archives comes from the same host
        // as the document itself
        if (docURL == null) {
            se = new SecurityException
                (Messages.formatMessage(ERROR_CANNOT_ACCESS_DOCUMENT_URL,
                                        new Object[]{scriptURL}));
        } else {
            if ( !docURL.equals(scriptURL)
                 &&
                 (scriptURL == null
                  ||
                  !DATA_PROTOCOL.equals(scriptURL.getProtocol()) )) {
                se = new SecurityException
                    (Messages.formatMessage(ERROR_SCRIPT_NOT_EMBEDED,
                                            new Object[]{scriptURL}));
            }
        }
    }
}
