1 /*
   2  * Copyright (c) 1994, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.net.www.protocol.file;
  27 
  28 import java.net.InetAddress;
  29 import java.net.URLConnection;
  30 import java.net.URL;
  31 import java.net.Proxy;
  32 import java.net.MalformedURLException;
  33 import java.net.URLStreamHandler;
  34 import java.io.InputStream;
  35 import java.io.IOException;
  36 import sun.net.www.ParseUtil;
  37 import java.io.File;
  38 
  39 /**
  40  * Open an file input stream given a URL.
  41  * @author      James Gosling
  42  */
  43 public class Handler extends URLStreamHandler {
  44 
  45     private String getHost(URL url) {
  46         String host = url.getHost();
  47         if (host == null)
  48             host = "";
  49         return host;
  50     }
  51 
  52 
  53     protected void parseURL(URL u, String spec, int start, int limit) {
  54         /*
  55          * Ugly backwards compatibility. Flip any file separator
  56          * characters to be forward slashes. This is a nop on Unix
  57          * and "fixes" win32 file paths. According to RFC 2396,
  58          * only forward slashes may be used to represent hierarchy
  59          * separation in a URL but previous releases unfortunately
  60          * performed this "fixup" behavior in the file URL parsing code
  61          * rather than forcing this to be fixed in the caller of the URL
  62          * class where it belongs. Since backslash is an "unwise"
  63          * character that would normally be encoded if literally intended
  64          * as a non-seperator character the damage of veering away from the
  65          * specification is presumably limited.
  66          */
  67         super.parseURL(u, spec.replace(File.separatorChar, '/'), start, limit);
  68     }
  69 
  70     public synchronized URLConnection openConnection(URL u)
  71         throws IOException {
  72         return openConnection(u, null);
  73     }
  74 
  75     public synchronized URLConnection openConnection(URL u, Proxy p)
  76            throws IOException {
  77         String host = u.getHost();
  78         if (host == null || host.isEmpty() || host.equals("~") ||
  79             host.equalsIgnoreCase("localhost")) {
  80             File file = new File(ParseUtil.decode(u.getPath()));
  81             return createFileURLConnection(u, file);
  82         }
  83 
  84         /* If you reach here, it implies that you have a hostname
  85            so attempt an ftp connection.
  86          */
  87         URLConnection uc;
  88         URL ru;
  89 
  90         try {
  91             ru = new URL("ftp", host, u.getFile() +
  92                              (u.getRef() == null ? "": "#" + u.getRef()));
  93             if (p != null) {
  94                 uc = ru.openConnection(p);
  95             } else {
  96                 uc = ru.openConnection();
  97             }
  98         } catch (IOException e) {
  99             uc = null;
 100         }
 101         if (uc == null) {
 102             throw new IOException("Unable to connect to: " +
 103                                                        u.toExternalForm());
 104         }
 105         return uc;
 106     }
 107 
 108     // Template method to be overridden by Java Plug-in. [stanleyh]
 109     //
 110     protected URLConnection createFileURLConnection(URL u, File file)
 111     {
 112         return new FileURLConnection(u, file);
 113     }
 114 
 115     /**
 116      * Compares the host components of two URLs.
 117      * @param u1 the URL of the first host to compare
 118      * @param u2 the URL of the second host to compare
 119      * @return  {@code true} if and only if they
 120      * are equal, {@code false} otherwise.
 121      */
 122     protected boolean hostsEqual(URL u1, URL u2) {
 123         /*
 124          * Special case for file: URLs
 125          * per RFC 1738 no hostname is equivalent to 'localhost'
 126          * i.e. file:///path is equal to file://localhost/path
 127          */
 128         String s1 = u1.getHost();
 129         String s2 = u2.getHost();
 130         if ("localhost".equalsIgnoreCase(s1) && ( s2 == null || "".equals(s2)))
 131             return true;
 132         if ("localhost".equalsIgnoreCase(s2) && ( s1 == null || "".equals(s1)))
 133             return true;
 134         return super.hostsEqual(u1, u2);
 135     }
 136 }