/**

  * Back 2 Browser Bytecode Translator

  * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, version 2 of the License.

  *

  * This program 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 for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. Look for COPYING file in the top folder.

  * If not, see http://opensource.org/licenses/GPL-2.0.

  */

 package org.apidesign.vm4brwsr;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URL;

 import java.util.Enumeration;

 /** Implementation of Resources that delegates to some class loader.

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 final class LdrRsrcs implements Bck2Brwsr.Resources {

     private final String module;

     private final ClassLoader loader;

     LdrRsrcs(ClassLoader loader) {

         this(null, loader);

     }

     LdrRsrcs(String module, ClassLoader loader) {

         this.module = module;

         this.loader = loader;

     }

     @Override

     public InputStream get(String name) throws IOException {

         final URL url = findSource(name);

         if (url == null) {

             return null;

         }

         if (module != null) {

             final String resourceModule = getModule(url);

             if ((resourceModule != null) && !module.equals(resourceModule)) {

                 return null;

             }

         }

         return url.openStream();

     }

     private URL findSource(String name) throws IOException {

         Enumeration<URL> en = loader.getResources(name);

         URL u = null;

         while (en.hasMoreElements()) {

             u = en.nextElement();

         }

         return u;

     }

     private static String getModule(URL url) throws IOException {

         if (!"jar".equalsIgnoreCase(url.getProtocol())) {

             return null;

         }

         final String fullPathString = url.getPath();

         final int sepIndex = fullPathString.indexOf('!');

         final String jarPathString =

                 (sepIndex != -1) ? fullPathString.substring(0, sepIndex)

                                  : fullPathString;

         if (!jarPathString.endsWith(".jar")) {

             return null;

         }

         String moduleName =

                 jarPathString.substring(

                                   jarPathString.lastIndexOf('/') + 1,

                                   jarPathString.length() - 4);

         if (moduleName.endsWith("-SNAPSHOT")) {

             moduleName = moduleName.substring(

                                         0, moduleName.length() - 9);

         }

         final int dashIndex = moduleName.lastIndexOf('-');

         if (dashIndex != -1) {

             moduleName = moduleName.substring(0, dashIndex);

         }

         return moduleName;

     }

 }