1 /*
2 * Copyright (c) 2016, 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 jdk.internal.module;
27
28 import java.io.IOException;
29 import java.io.UncheckedIOException;
30 import java.lang.module.ModuleDescriptor;
31 import java.lang.module.ModuleReader;
32 import java.lang.module.ModuleReference;
33 import java.net.URI;
34 import java.util.Objects;
35 import java.util.function.Supplier;
36
37 /**
38 * A ModuleReference implementation that supports referencing a module that
39 * is patched and/or can be tied to other modules by means of hashes.
40 */
41
42 public class ModuleReferenceImpl extends ModuleReference {
43
44 private final Supplier<ModuleReader> readerSupplier;
45
46 // non-null if the module is patched
47 private final ModulePatcher patcher;
48
49 // the hashes of other modules recorded in this module
50 private final ModuleHashes recordedHashes;
51
52 // the function that computes the hash of this module
53 private final ModuleHashes.HashSupplier hasher;
54
55 // ModuleResolution flags
56 private final ModuleResolution moduleResolution;
57
58 // cached hash of this module to avoid needing to compute it many times
59 private byte[] cachedHash;
60
61 /**
62 * Constructs a new instance of this class.
63 */
64 ModuleReferenceImpl(ModuleDescriptor descriptor,
65 URI location,
66 Supplier<ModuleReader> readerSupplier,
67 ModulePatcher patcher,
68 ModuleHashes recordedHashes,
69 ModuleHashes.HashSupplier hasher,
70 ModuleResolution moduleResolution)
71 {
72 super(descriptor, Objects.requireNonNull(location));
73 this.readerSupplier = readerSupplier;
74 this.patcher = patcher;
75 this.recordedHashes = recordedHashes;
76 this.hasher = hasher;
77 this.moduleResolution = moduleResolution;
78 }
79
80 @Override
81 public ModuleReader open() throws IOException {
82 try {
83 return readerSupplier.get();
84 } catch (UncheckedIOException e) {
85 throw e.getCause();
86 }
87 }
88
89 /**
90 * Returns {@code true} if this module has been patched via --patch-module.
91 */
92 public boolean isPatched() {
93 return (patcher != null);
94 }
95
96 /**
97 * Returns the hashes recorded in this module or {@code null} if there
98 * are no hashes recorded.
99 */
100 public ModuleHashes recordedHashes() {
101 return recordedHashes;
102 }
103
104 /**
105 * Returns the supplier that computes the hash of this module.
106 */
107 ModuleHashes.HashSupplier hasher() {
108 return hasher;
109 }
110
111 /**
112 * Returns the ModuleResolution flags.
113 */
114 public ModuleResolution moduleResolution() {
115 return moduleResolution;
116 }
117
118 /**
119 * Computes the hash of this module. Returns {@code null} if the hash
120 * cannot be computed.
121 *
122 * @throws java.io.UncheckedIOException if an I/O error occurs
123 */
124 public byte[] computeHash(String algorithm) {
125 byte[] result = cachedHash;
126 if (result != null)
127 return result;
128 if (hasher == null)
129 return null;
130 cachedHash = result = hasher.generate(algorithm);
131 return result;
132 }
133
134 @Override
135 public int hashCode() {
136 int hc = hash;
137 if (hc == 0) {
138 hc = descriptor().hashCode();
139 hc = 43 * hc + Objects.hashCode(location());
140 hc = 43 * hc + Objects.hashCode(patcher);
141 if (hc == 0)
142 hc = -1;
143 hash = hc;
144 }
145 return hc;
146 }
147
148 private int hash;
149
150 @Override
151 public boolean equals(Object ob) {
152 if (!(ob instanceof ModuleReferenceImpl))
153 return false;
154 ModuleReferenceImpl that = (ModuleReferenceImpl)ob;
155
156 // assume module content, recorded hashes, etc. are the same
157 // when the modules have equal module descriptors, are at the
158 // same location, and are patched by the same patcher.
159 return Objects.equals(this.descriptor(), that.descriptor())
160 && Objects.equals(this.location(), that.location())
161 && Objects.equals(this.patcher, that.patcher);
162 }
163
164 @Override
165 public String toString() {
166 return super.toString();
167 }
168
169 }