jurt/com/sun/star/lib/util/NativeLibraryLoader.java

   1 /*
   2  * This file is part of the LibreOffice project.
   3  *
   4  * This Source Code Form is subject to the terms of the Mozilla Public
   5  * License, v. 2.0. If a copy of the MPL was not distributed with this
   6  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   7  *
   8  * This file incorporates work covered by the following license notice:
   9  *
  10  *   Licensed to the Apache Software Foundation (ASF) under one or more
  11  *   contributor license agreements. See the NOTICE file distributed
  12  *   with this work for additional information regarding copyright
  13  *   ownership. The ASF licenses this file to you under the Apache
  14  *   License, Version 2.0 (the "License"); you may not use this file
  15  *   except in compliance with the License. You may obtain a copy of
  16  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  17  */
  18 package com.sun.star.lib.util;
  19
  20 import java.io.File;
  21 import java.net.URL;
  22 import java.net.URLClassLoader;
  23
  24 /**
  25  * Helper functions to locate and load native files.
  26  *
  27  * <p>The methods in this class are designed to find the requested resources in
  28  * as many cases as possible.  They search various places, roughly from most
  29  * specific to most general.  This works well if a component is known to bring
  30  * with it a certain resource, and that resource has to be found.  However, it
  31  * might not work very well in cases where you want to check whether a
  32  * component brings with it a certain resource or not: a similarly named
  33  * resource from another component might be found by the eager search
  34  * algorithm.</p>
  35  */
  36 public final class NativeLibraryLoader {
  37     /**
  38      * Load a system library, using a given class loader to locate the library.
  39      *
  40      * <p>This is similar to <code>System.loadLibrary</code>.</p>
  41      *
  42      * @param loader a class loader; may be null.
  43      * @param libname the library name; how this name is mapped to a system
  44      * library name is system dependent.
  45      */
  46     public static void loadLibrary(ClassLoader loader, String libname) {
  47         String sysname = System.mapLibraryName(libname);
  48         // At least Oracle's 1.7.0_51 now maps to .dylib rather than .jnilib:
  49         if (System.getProperty("os.name").startsWith("Mac")
  50             && sysname.endsWith(".dylib"))
  51         {
  52             sysname
  53                 = sysname.substring(0, sysname.length() - "dylib".length())
  54                 + "jnilib";
  55         }
  56         File path = getResource(loader, sysname);
  57         if (path == null) {
  58             // If the library cannot be found as a class loader resource, try
  59             // the global System.loadLibrary as a last resort:
  60             System.loadLibrary(libname);
  61         } else {
  62             System.load(path.getAbsolutePath());
  63         }
  64     }
  65
  66     /**
  67      * Locate a system resource, using a given class loader.
  68      *
  69      * <p>This is similar to <code>ClassLoader.getResource</code>, but only works
  70      * for local resources (local files), and adds additional functionality for
  71      * <code>URLClassLoaders</code>.</p>
  72      *
  73      * @param loader a class loader; may be null.
  74      * @param name a resource name (that is, the name of a file).
  75      * @return a File locating the resource, or null if the resource was not
  76      * found.
  77      */
  78     public static File getResource(ClassLoader loader, String name) {
  79         if (loader != null) {
  80             File path = UrlToFileMapper.mapUrlToFile(loader.getResource(name));
  81             if (path != null) {
  82                 return path;
  83             }
  84         }
  85         // URLClassLoaders work on lists of URLs, which are typically URLs
  86         // locating JAR files (scheme://auth/dir1/dir2/some.jar).  The following
  87         // code looks for resource name beside the JAR file
  88         // (scheme://auth/dir1/dir2/name) and one directory up
  89         // (scheme://auth/dir1/name).  The second step is important in a typical
  90         // OOo installation, where the JAR files are in the program/classes
  91         // directory while the shared libraries are in the program directory.
  92         if (!(loader instanceof URLClassLoader)) {
  93             return null;
  94         }
  95         URL[] urls = ((URLClassLoader) loader).getURLs();
  96         for (int i = 0; i < urls.length; ++i) {
  97             File path = UrlToFileMapper.mapUrlToFile(urls[i]);
  98             if (path != null) {
  99                 File dir = path.isDirectory() ? path : path.getParentFile();
 100                 if (dir != null) {
 101                     path = new File(dir, name);
 102                     if (path.exists()) {
 103                         return path;
 104                     }
 105                     dir = dir.getParentFile();
 106                     if (dir != null) {
 107                         path = new File(dir, name);
 108                         if (path.exists()) {
 109                             return path;
 110                         }
 111                         // On OS X, dir is now the Resources dir,
 112                         // we want to look in Frameworks
 113                         if (System.getProperty("os.name").startsWith("Mac")
 114                             && dir.getName().equals("Resources")) {
 115                             dir = dir.getParentFile();
 116                             path = new File(dir, "Frameworks/" + name);
 117                             if (path.exists()) {
 118                                 return path;
 119                             }
 120                         }
 121                     }
 122                 }
 123             }
 124         }
 125         return null;
 126     }
 127
 128     private NativeLibraryLoader() {} // do not instantiate
 129 }