1/*
2 * Copyright (c) 1998, 2009, 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
26package sun.misc;
27
28import java.io.EOFException;
29import java.net.URL;
30import java.io.IOException;
31import java.io.InterruptedIOException;
32import java.io.InputStream;
33import java.security.CodeSigner;
34import java.util.jar.Manifest;
35import java.nio.ByteBuffer;
36import java.util.Arrays;
37import sun.nio.ByteBuffered;
38
39/**
40 * This class is used to represent a Resource that has been loaded
41 * from the class path.
42 *
43 * @author  David Connelly
44 * @since   1.2
45 */
46public abstract class Resource {
47    /**
48     * Returns the name of the Resource.
49     */
50    public abstract String getName();
51
52    /**
53     * Returns the URL of the Resource.
54     */
55    public abstract URL getURL();
56
57    /**
58     * Returns the CodeSource URL for the Resource.
59     */
60    public abstract URL getCodeSourceURL();
61
62    /**
63     * Returns an InputStream for reading the Resource data.
64     */
65    public abstract InputStream getInputStream() throws IOException;
66
67    /**
68     * Returns the length of the Resource data, or -1 if unknown.
69     */
70    public abstract int getContentLength() throws IOException;
71
72    private InputStream cis;
73
74    /* Cache result in case getBytes is called after getByteBuffer. */
75    private synchronized InputStream cachedInputStream() throws IOException {
76        if (cis == null) {
77            cis = getInputStream();
78        }
79        return cis;
80    }
81
82    /**
83     * Returns the Resource data as an array of bytes.
84     */
85    public byte[] getBytes() throws IOException {
86        byte[] b;
87        // Get stream before content length so that a FileNotFoundException
88        // can propagate upwards without being caught too early
89        InputStream in = cachedInputStream();
90
91        // This code has been uglified to protect against interrupts.
92        // Even if a thread has been interrupted when loading resources,
93        // the IO should not abort, so must carefully retry, failing only
94        // if the retry leads to some other IO exception.
95
96        boolean isInterrupted = Thread.interrupted();
97        int len;
98        for (;;) {
99            try {
100                len = getContentLength();
101                break;
102            } catch (InterruptedIOException iioe) {
103                Thread.interrupted();
104                isInterrupted = true;
105            }
106        }
107
108        try {
109            b = new byte[0];
110            if (len == -1) len = Integer.MAX_VALUE;
111            int pos = 0;
112            while (pos < len) {
113                int bytesToRead;
114                if (pos >= b.length) { // Only expand when there's no room
115                    bytesToRead = Math.min(len - pos, b.length + 1024);
116                    if (b.length < pos + bytesToRead) {
117                        b = Arrays.copyOf(b, pos + bytesToRead);
118                    }
119                } else {
120                    bytesToRead = b.length - pos;
121                }
122                int cc = 0;
123                try {
124                    cc = in.read(b, pos, bytesToRead);
125                } catch (InterruptedIOException iioe) {
126                    Thread.interrupted();
127                    isInterrupted = true;
128                }
129                if (cc < 0) {
130                    if (len != Integer.MAX_VALUE) {
131                        throw new EOFException("Detect premature EOF");
132                    } else {
133                        if (b.length != pos) {
134                            b = Arrays.copyOf(b, pos);
135                        }
136                        break;
137                    }
138                }
139                pos += cc;
140            }
141        } finally {
142            try {
143                in.close();
144            } catch (InterruptedIOException iioe) {
145                isInterrupted = true;
146            } catch (IOException ignore) {}
147
148            if (isInterrupted) {
149                Thread.currentThread().interrupt();
150            }
151        }
152        return b;
153    }
154
155    /**
156     * Returns the Resource data as a ByteBuffer, but only if the input stream
157     * was implemented on top of a ByteBuffer. Return <tt>null</tt> otherwise.
158     */
159    public ByteBuffer getByteBuffer() throws IOException {
160        InputStream in = cachedInputStream();
161        if (in instanceof ByteBuffered) {
162            return ((ByteBuffered)in).getByteBuffer();
163        }
164        return null;
165    }
166
167    /**
168     * Returns the Manifest for the Resource, or null if none.
169     */
170    public Manifest getManifest() throws IOException {
171        return null;
172    }
173
174    /**
175     * Returns theCertificates for the Resource, or null if none.
176     */
177    public java.security.cert.Certificate[] getCertificates() {
178        return null;
179    }
180
181    /**
182     * Returns the code signers for the Resource, or null if none.
183     */
184    public CodeSigner[] getCodeSigners() {
185        return null;
186    }
187}
188