Mon, 18 Feb 2013 16:00:15 +0100
8008371: Fix Dynalink compiler warnings and whitespace
Reviewed-by: jlaskey, sundar
1 /*
2 * Copyright (c) 2010, 2013, 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
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24 */
26 /*
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file, and Oracle licenses the original version of this file under the BSD
31 * license:
32 */
33 /*
34 Copyright 2009-2013 Attila Szegedi
36 Licensed under both the Apache License, Version 2.0 (the "Apache License")
37 and the BSD License (the "BSD License"), with licensee being free to
38 choose either of the two at their discretion.
40 You may not use this file except in compliance with either the Apache
41 License or the BSD License.
43 If you choose to use this file in compliance with the Apache License, the
44 following notice applies to you:
46 You may obtain a copy of the Apache License at
48 http://www.apache.org/licenses/LICENSE-2.0
50 Unless required by applicable law or agreed to in writing, software
51 distributed under the License is distributed on an "AS IS" BASIS,
52 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
53 implied. See the License for the specific language governing
54 permissions and limitations under the License.
56 If you choose to use this file in compliance with the BSD License, the
57 following notice applies to you:
59 Redistribution and use in source and binary forms, with or without
60 modification, are permitted provided that the following conditions are
61 met:
62 * Redistributions of source code must retain the above copyright
63 notice, this list of conditions and the following disclaimer.
64 * Redistributions in binary form must reproduce the above copyright
65 notice, this list of conditions and the following disclaimer in the
66 documentation and/or other materials provided with the distribution.
67 * Neither the name of the copyright holder nor the names of
68 contributors may be used to endorse or promote products derived from
69 this software without specific prior written permission.
71 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
72 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
73 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
74 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER
75 BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
76 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
77 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
78 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
79 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
80 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
81 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
82 */
84 package jdk.internal.dynalink.support;
86 import java.lang.invoke.MethodHandle;
87 import java.lang.invoke.MethodHandles;
88 import java.lang.invoke.MethodType;
89 import java.lang.invoke.WrongMethodTypeException;
90 import java.util.LinkedList;
91 import java.util.List;
92 import jdk.internal.dynalink.linker.ConversionComparator;
93 import jdk.internal.dynalink.linker.ConversionComparator.Comparison;
94 import jdk.internal.dynalink.linker.GuardedInvocation;
95 import jdk.internal.dynalink.linker.GuardingTypeConverterFactory;
96 import jdk.internal.dynalink.linker.LinkerServices;
98 /**
99 * A factory for type converters. This class is the main implementation behind the
100 * {@link LinkerServices#asType(MethodHandle, MethodType)}. It manages the known {@link GuardingTypeConverterFactory}
101 * instances and creates appropriate converters for method handles.
102 *
103 * @author Attila Szegedi
104 */
105 public class TypeConverterFactory {
107 private final GuardingTypeConverterFactory[] factories;
108 private final ConversionComparator[] comparators;
110 private final ClassValue<ClassMap<MethodHandle>> converterMap = new ClassValue<ClassMap<MethodHandle>>() {
111 @Override
112 protected ClassMap<MethodHandle> computeValue(final Class<?> sourceType) {
113 return new ClassMap<MethodHandle>(sourceType.getClassLoader()) {
114 @Override
115 protected MethodHandle computeValue(Class<?> targetType) {
116 try {
117 return createConverter(sourceType, targetType);
118 } catch (RuntimeException e) {
119 throw e;
120 } catch (Exception e) {
121 throw new RuntimeException(e);
122 }
123 }
124 };
125 }
126 };
128 private final ClassValue<ClassMap<MethodHandle>> converterIdentityMap = new ClassValue<ClassMap<MethodHandle>>() {
129 @Override
130 protected ClassMap<MethodHandle> computeValue(final Class<?> sourceType) {
131 return new ClassMap<MethodHandle>(sourceType.getClassLoader()) {
132 @Override
133 protected MethodHandle computeValue(Class<?> targetType) {
134 if(!canAutoConvert(sourceType, targetType)) {
135 final MethodHandle converter = getTypeConverterNull(sourceType, targetType);
136 if(converter != null) {
137 return converter;
138 }
139 }
140 return IDENTITY_CONVERSION.asType(MethodType.methodType(targetType, sourceType));
141 }
142 };
143 }
144 };
146 /**
147 * Creates a new type converter factory from the available {@link GuardingTypeConverterFactory} instances.
148 *
149 * @param factories the {@link GuardingTypeConverterFactory} instances to compose.
150 */
151 public TypeConverterFactory(Iterable<? extends GuardingTypeConverterFactory> factories) {
152 final List<GuardingTypeConverterFactory> l = new LinkedList<>();
153 final List<ConversionComparator> c = new LinkedList<>();
154 for(GuardingTypeConverterFactory factory: factories) {
155 l.add(factory);
156 if(factory instanceof ConversionComparator) {
157 c.add((ConversionComparator)factory);
158 }
159 }
160 this.factories = l.toArray(new GuardingTypeConverterFactory[l.size()]);
161 this.comparators = c.toArray(new ConversionComparator[c.size()]);
163 }
165 /**
166 * Similar to {@link MethodHandle#asType(MethodType)} except it also hooks in method handles produced by
167 * {@link GuardingTypeConverterFactory} implementations, providing for language-specific type coercing of
168 * parameters. It will apply {@link MethodHandle#asType(MethodType)} for all primitive-to-primitive,
169 * wrapper-to-primitive, primitive-to-wrapper conversions as well as for all upcasts. For all other conversions,
170 * it'll insert {@link MethodHandles#filterArguments(MethodHandle, int, MethodHandle...)} with composite filters
171 * provided by {@link GuardingTypeConverterFactory} implementations.
172 *
173 * @param handle target method handle
174 * @param fromType the types of source arguments
175 * @return a method handle that is a suitable combination of {@link MethodHandle#asType(MethodType)} and
176 * {@link MethodHandles#filterArguments(MethodHandle, int, MethodHandle...)} with
177 * {@link GuardingTypeConverterFactory} produced type converters as filters.
178 */
179 public MethodHandle asType(MethodHandle handle, final MethodType fromType) {
180 MethodHandle newHandle = handle;
181 final MethodType toType = newHandle.type();
182 final int l = toType.parameterCount();
183 if(l != fromType.parameterCount()) {
184 throw new WrongMethodTypeException("Parameter counts differ: " + handle.type() + " vs. " + fromType);
185 }
186 int pos = 0;
187 final List<MethodHandle> converters = new LinkedList<>();
188 for(int i = 0; i < l; ++i) {
189 final Class<?> fromParamType = fromType.parameterType(i);
190 final Class<?> toParamType = toType.parameterType(i);
191 if(canAutoConvert(fromParamType, toParamType)) {
192 newHandle = applyConverters(newHandle, pos, converters);
193 } else {
194 final MethodHandle converter = getTypeConverterNull(fromParamType, toParamType);
195 if(converter != null) {
196 if(converters.isEmpty()) {
197 pos = i;
198 }
199 converters.add(converter);
200 } else {
201 newHandle = applyConverters(newHandle, pos, converters);
202 }
203 }
204 }
205 newHandle = applyConverters(newHandle, pos, converters);
207 // Convert return type
208 final Class<?> fromRetType = fromType.returnType();
209 final Class<?> toRetType = toType.returnType();
210 if(fromRetType != Void.TYPE && toRetType != Void.TYPE) {
211 if(!canAutoConvert(toRetType, fromRetType)) {
212 final MethodHandle converter = getTypeConverterNull(toRetType, fromRetType);
213 if(converter != null) {
214 newHandle = MethodHandles.filterReturnValue(newHandle, converter);
215 }
216 }
217 }
219 // Take care of automatic conversions
220 return newHandle.asType(fromType);
221 }
223 private static MethodHandle applyConverters(MethodHandle handle, int pos, List<MethodHandle> converters) {
224 if(converters.isEmpty()) {
225 return handle;
226 }
227 final MethodHandle newHandle =
228 MethodHandles.filterArguments(handle, pos, converters.toArray(new MethodHandle[converters.size()]));
229 converters.clear();
230 return newHandle;
231 }
233 /**
234 * Returns true if there might exist a conversion between the requested types (either an automatic JVM conversion,
235 * or one provided by any available {@link GuardingTypeConverterFactory}), or false if there definitely does not
236 * exist a conversion between the requested types. Note that returning true does not guarantee that the conversion
237 * will succeed at runtime (notably, if the "from" or "to" types are sufficiently generic), but returning false
238 * guarantees that it would fail.
239 *
240 * @param from the source type for the conversion
241 * @param to the target type for the conversion
242 * @return true if there can be a conversion, false if there can not.
243 */
244 public boolean canConvert(final Class<?> from, final Class<?> to) {
245 return canAutoConvert(from, to) || getTypeConverterNull(from, to) != null;
246 }
248 /**
249 * Determines which of the two type conversions from a source type to the two target types is preferred. This is
250 * used for dynamic overloaded method resolution. If the source type is convertible to exactly one target type with
251 * a method invocation conversion, it is chosen, otherwise available {@link ConversionComparator}s are consulted.
252 * @param sourceType the source type.
253 * @param targetType1 one potential target type
254 * @param targetType2 another potential target type.
255 * @return one of Comparison constants that establish which - if any - of the target types is preferable for the
256 * conversion.
257 */
258 public Comparison compareConversion(Class<?> sourceType, Class<?> targetType1, Class<?> targetType2) {
259 for(ConversionComparator comparator: comparators) {
260 final Comparison result = comparator.compareConversion(sourceType, targetType1, targetType2);
261 if(result != Comparison.INDETERMINATE) {
262 return result;
263 }
264 }
265 if(TypeUtilities.isMethodInvocationConvertible(sourceType, targetType1)) {
266 if(!TypeUtilities.isMethodInvocationConvertible(sourceType, targetType2)) {
267 return Comparison.TYPE_1_BETTER;
268 }
269 } else if(TypeUtilities.isMethodInvocationConvertible(sourceType, targetType2)) {
270 return Comparison.TYPE_2_BETTER;
271 }
272 return Comparison.INDETERMINATE;
273 }
275 /**
276 * Determines whether it's safe to perform an automatic conversion between the source and target class.
277 *
278 * @param fromType convert from this class
279 * @param toType convert to this class
280 * @return true if it's safe to let MethodHandles.convertArguments() to handle this conversion.
281 */
282 /*private*/ static boolean canAutoConvert(final Class<?> fromType, final Class<?> toType) {
283 return TypeUtilities.isMethodInvocationConvertible(fromType, toType);
284 }
286 /*private*/ MethodHandle getTypeConverterNull(Class<?> sourceType, Class<?> targetType) {
287 final MethodHandle converter = converterMap.get(sourceType).get(targetType);
288 return converter == IDENTITY_CONVERSION ? null : converter;
289 }
291 /**
292 * Given a source and target type, returns a method handle that converts between them. Never returns null; in worst
293 * case it will return an identity conversion (that might fail for some values at runtime). You can use this method
294 * if you have a piece of your program that is written in Java, and you need to reuse existing type conversion
295 * machinery in a non-invokedynamic context.
296 * @param sourceType the type to convert from
297 * @param targetType the type to convert to
298 * @return a method handle performing the conversion.
299 */
300 public MethodHandle getTypeConverter(Class<?> sourceType, Class<?> targetType) {
301 return converterIdentityMap.get(sourceType).get(targetType);
302 }
304 /*private*/ MethodHandle createConverter(Class<?> sourceType, Class<?> targetType) throws Exception {
305 final MethodType type = MethodType.methodType(targetType, sourceType);
306 final MethodHandle identity = IDENTITY_CONVERSION.asType(type);
307 MethodHandle last = identity;
308 for(int i = factories.length; i-- > 0;) {
309 final GuardedInvocation next = factories[i].convertToType(sourceType, targetType);
310 if(next != null) {
311 next.assertType(type);
312 last = next.compose(last);
313 }
314 }
315 return last == identity ? IDENTITY_CONVERSION : last;
316 }
318 /*private*/ static final MethodHandle IDENTITY_CONVERSION = MethodHandles.identity(Object.class);
319 }