1 /*
  2  * Copyright (c) 2014, 2025, 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.jrt;
 27 
 28 import java.io.ByteArrayInputStream;
 29 import java.io.IOException;
 30 import java.io.InputStream;
 31 import java.io.UncheckedIOException;
 32 import java.net.MalformedURLException;
 33 import java.net.URL;
 34 
 35 import jdk.internal.jimage.ImageReader;
 36 import jdk.internal.jimage.ImageReader.Node;
 37 import jdk.internal.jimage.SystemImageReader;
 38 
 39 import sun.net.www.ParseUtil;
 40 import sun.net.www.URLConnection;
 41 
 42 /**
 43  * URLConnection implementation that can be used to connect to resources
 44  * contained in the runtime image. See section "New URI scheme for naming stored
 45  * modules, classes, and resources" in <a href="https://openjdk.org/jeps/220">
 46  * JEP 220</a>.
 47  */
 48 public class JavaRuntimeURLConnection extends URLConnection {
 49 
 50     // ImageReader to access resources in jimage.
 51     private static final ImageReader READER = SystemImageReader.get();
 52 
 53     // The module and resource name in the URL (i.e. "jrt:/[$MODULE[/$PATH]]").
 54     //
 55     // The module name is not percent-decoded, and can be empty.
 56     private final String module;
 57     // The resource name permits UTF-8 percent encoding of non-ASCII characters.
 58     private final String path;
 59 
 60     // The resource node (non-null when connected).
 61     private Node resourceNode;
 62 
 63     JavaRuntimeURLConnection(URL url) throws IOException {
 64         super(url);
 65         String urlPath = url.getPath();
 66         if (urlPath.isEmpty() || urlPath.charAt(0) != '/') {
 67             throw new MalformedURLException(url + " missing path or /");
 68         }
 69         int pathSep = urlPath.indexOf('/', 1);
 70         if (pathSep == -1) {
 71             // No trailing resource path. This can never "connect" or return a
 72             // resource (see JEP 220 for details).
 73             this.module = urlPath.substring(1);
 74             this.path = null;
 75         } else {
 76             this.module = urlPath.substring(1, pathSep);
 77             this.path = percentDecode(urlPath.substring(pathSep + 1));
 78         }
 79     }
 80 
 81     /**
 82      * Finds and caches the resource node associated with this URL and marks the
 83      * connection as "connected".
 84      */
 85     private synchronized Node connectResourceNode() throws IOException {
 86         if (resourceNode == null) {
 87             if (module.isEmpty() || path == null) {
 88                 throw new IOException("cannot connect to jrt:/" + module);
 89             }
 90             Node node = READER.findResourceNode(module, path);
 91             if (node == null) {
 92                 throw new IOException(module + "/" + path + " not found");
 93             }
 94             this.resourceNode = node;
 95             super.connected = true;
 96         }
 97         return resourceNode;
 98     }
 99 
100     @Override
101     public void connect() throws IOException {
102         connectResourceNode();
103     }
104 
105     @Override
106     public InputStream getInputStream() throws IOException {
107         return new ByteArrayInputStream(READER.getResource(connectResourceNode()));
108     }
109 
110     @Override
111     public long getContentLengthLong() {
112         // Note: UncheckedIOException is thrown by the Node subclass in
113         // ExplodedImage (this not obvious, so worth calling out).
114         try {
115             return connectResourceNode().size();
116         } catch (IOException | UncheckedIOException ioe) {
117             return -1L;
118         }
119     }
120 
121     @Override
122     public int getContentLength() {
123         long len = getContentLengthLong();
124         return len > Integer.MAX_VALUE ? -1 : (int)len;
125     }
126 
127     // Perform percent decoding of the resource name/path from the URL.
128     private static String percentDecode(String path) throws MalformedURLException {
129         if (path.indexOf('%') == -1) {
130             // Nothing to decode (overwhelmingly common case).
131             return path;
132         }
133         // Any additional special case decoding logic should go here.
134         try {
135             return ParseUtil.decode(path);
136         } catch (IllegalArgumentException e) {
137             throw new MalformedURLException(e.getMessage());
138         }
139     }
140 }