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      1 /*
      2  * Copyright (C) 2010 Google Inc.
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  * http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.google.doclava;
     18 
     19 import java.io.File;
     20 import java.io.FileOutputStream;
     21 import java.io.IOException;
     22 import java.io.InputStream;
     23 import java.net.URL;
     24 import java.util.Enumeration;
     25 import java.util.jar.JarEntry;
     26 import java.util.jar.JarFile;
     27 
     28 public class JarUtils {
     29   /**
     30    * Returns the jar file used to load class clazz, or defaultJar if clazz was not loaded from a
     31    * jar.
     32    */
     33   public static JarFile jarForClass(Class<?> clazz, JarFile defaultJar) {
     34     String path = "/" + clazz.getName().replace('.', '/') + ".class";
     35     URL jarUrl = clazz.getResource(path);
     36     if (jarUrl == null) {
     37       return defaultJar;
     38     }
     39 
     40     String url = jarUrl.toString();
     41     int bang = url.indexOf("!");
     42     String JAR_URI_PREFIX = "jar:file:";
     43     if (url.startsWith(JAR_URI_PREFIX) && bang != -1) {
     44       try {
     45         return new JarFile(url.substring(JAR_URI_PREFIX.length(), bang));
     46       } catch (IOException e) {
     47         throw new IllegalStateException("Error loading jar file.", e);
     48       }
     49     } else {
     50       return defaultJar;
     51     }
     52   }
     53 
     54   /**
     55    * Copies a directory from a jar file to an external directory.
     56    */
     57   public static void copyResourcesToDirectory(JarFile fromJar, String jarDir, String destDir)
     58       throws IOException {
     59     for (Enumeration<JarEntry> entries = fromJar.entries(); entries.hasMoreElements();) {
     60       JarEntry entry = entries.nextElement();
     61       if (entry.getName().startsWith(jarDir + "/") && !entry.isDirectory()) {
     62         File dest = new File(destDir + "/" + entry.getName().substring(jarDir.length() + 1));
     63         File parent = dest.getParentFile();
     64         if (parent != null) {
     65           parent.mkdirs();
     66         }
     67 
     68         FileOutputStream out = new FileOutputStream(dest);
     69         InputStream in = fromJar.getInputStream(entry);
     70 
     71         try {
     72           byte[] buffer = new byte[8 * 1024];
     73 
     74           int s = 0;
     75           while ((s = in.read(buffer)) > 0) {
     76             out.write(buffer, 0, s);
     77           }
     78         } catch (IOException e) {
     79           throw new IOException("Could not copy asset from jar file", e);
     80         } finally {
     81           try {
     82             in.close();
     83           } catch (IOException ignored) {}
     84           try {
     85             out.close();
     86           } catch (IOException ignored) {}
     87         }
     88       }
     89     }
     90 
     91   }
     92 
     93   private JarUtils() {} // non-instantiable
     94 }
     95