Thu, 24 May 2018 16:39:31 +0800
Merge
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
23 * questions.
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.beans;
86 import java.lang.invoke.MethodHandle;
87 import java.lang.invoke.MethodHandles;
88 import java.lang.invoke.MethodType;
89 import java.lang.reflect.Array;
90 import java.util.StringTokenizer;
91 import jdk.internal.dynalink.CallSiteDescriptor;
92 import jdk.internal.dynalink.linker.LinkerServices;
93 import jdk.internal.dynalink.support.Guards;
94 import jdk.internal.dynalink.support.Lookup;
96 /**
97 * Base class for dynamic methods that dispatch to a single target Java method or constructor. Handles adaptation of the
98 * target method to a call site type (including mapping variable arity methods to a call site signature with different
99 * arity).
100 * @author Attila Szegedi
101 */
102 abstract class SingleDynamicMethod extends DynamicMethod {
104 private static final MethodHandle CAN_CONVERT_TO = Lookup.findOwnStatic(MethodHandles.lookup(), "canConvertTo", boolean.class, LinkerServices.class, Class.class, Object.class);
106 SingleDynamicMethod(final String name) {
107 super(name);
108 }
110 /**
111 * Returns true if this method is variable arity.
112 * @return true if this method is variable arity.
113 */
114 abstract boolean isVarArgs();
116 /**
117 * Returns this method's native type.
118 * @return this method's native type.
119 */
120 abstract MethodType getMethodType();
122 /**
123 * Given a specified lookup, returns a method handle to this method's target.
124 * @param lookup the lookup to use.
125 * @return the handle to this method's target method.
126 */
127 abstract MethodHandle getTarget(MethodHandles.Lookup lookup);
129 @Override
130 MethodHandle getInvocation(final CallSiteDescriptor callSiteDescriptor, final LinkerServices linkerServices) {
131 return getInvocation(getTarget(callSiteDescriptor.getLookup()), callSiteDescriptor.getMethodType(),
132 linkerServices);
133 }
135 @Override
136 SingleDynamicMethod getMethodForExactParamTypes(final String paramTypes) {
137 return typeMatchesDescription(paramTypes, getMethodType()) ? this : null;
138 }
140 @Override
141 boolean contains(final SingleDynamicMethod method) {
142 return getMethodType().parameterList().equals(method.getMethodType().parameterList());
143 }
145 static String getMethodNameWithSignature(final MethodType type, final String methodName, final boolean withReturnType) {
146 final String typeStr = type.toString();
147 final int retTypeIndex = typeStr.lastIndexOf(')') + 1;
148 int secondParamIndex = typeStr.indexOf(',') + 1;
149 if(secondParamIndex == 0) {
150 secondParamIndex = retTypeIndex - 1;
151 }
152 final StringBuilder b = new StringBuilder();
153 if (withReturnType) {
154 b.append(typeStr, retTypeIndex, typeStr.length()).append(' ');
155 }
156 return b.append(methodName).append('(').append(typeStr, secondParamIndex, retTypeIndex).toString();
157 }
159 /**
160 * Given a method handle and a call site type, adapts the method handle to the call site type. Performs type
161 * conversions as needed using the specified linker services, and in case that the method handle is a vararg
162 * collector, matches it to the arity of the call site. The type of the return value is only changed if it can be
163 * converted using a conversion that loses neither precision nor magnitude, see
164 * {@link LinkerServices#asTypeLosslessReturn(MethodHandle, MethodType)}.
165 * @param target the method handle to adapt
166 * @param callSiteType the type of the call site
167 * @param linkerServices the linker services used for type conversions
168 * @return the adapted method handle.
169 */
170 static MethodHandle getInvocation(final MethodHandle target, final MethodType callSiteType, final LinkerServices linkerServices) {
171 final MethodHandle filteredTarget = linkerServices.filterInternalObjects(target);
172 final MethodType methodType = filteredTarget.type();
173 final int paramsLen = methodType.parameterCount();
174 final boolean varArgs = target.isVarargsCollector();
175 final MethodHandle fixTarget = varArgs ? filteredTarget.asFixedArity() : filteredTarget;
176 final int fixParamsLen = varArgs ? paramsLen - 1 : paramsLen;
177 final int argsLen = callSiteType.parameterCount();
178 if(argsLen < fixParamsLen) {
179 // Less actual arguments than number of fixed declared arguments; can't invoke.
180 return null;
181 }
182 // Method handle has the same number of fixed arguments as the call site type
183 if(argsLen == fixParamsLen) {
184 // Method handle that matches the number of actual arguments as the number of fixed arguments
185 final MethodHandle matchedMethod;
186 if(varArgs) {
187 // If vararg, add a zero-length array of the expected type as the last argument to signify no variable
188 // arguments.
189 matchedMethod = MethodHandles.insertArguments(fixTarget, fixParamsLen, Array.newInstance(
190 methodType.parameterType(fixParamsLen).getComponentType(), 0));
191 } else {
192 // Otherwise, just use the method
193 matchedMethod = fixTarget;
194 }
195 return createConvertingInvocation(matchedMethod, linkerServices, callSiteType);
196 }
198 // What's below only works for varargs
199 if(!varArgs) {
200 return null;
201 }
203 final Class<?> varArgType = methodType.parameterType(fixParamsLen);
204 // Handle a somewhat sinister corner case: caller passes exactly one argument in the vararg position, and we
205 // must handle both a prepacked vararg array as well as a genuine 1-long vararg sequence.
206 if(argsLen == paramsLen) {
207 final Class<?> callSiteLastArgType = callSiteType.parameterType(fixParamsLen);
208 if(varArgType.isAssignableFrom(callSiteLastArgType)) {
209 // Call site signature guarantees we'll always be passed a single compatible array; just link directly
210 // to the method, introducing necessary conversions. Also, preserve it being a variable arity method.
211 return createConvertingInvocation(filteredTarget, linkerServices, callSiteType).asVarargsCollector(
212 callSiteLastArgType);
213 }
215 // This method handle takes the single argument and packs it into a newly allocated single-element array. It
216 // will be used when the incoming argument can't be converted to the vararg array type (the "vararg packer"
217 // method).
218 final MethodHandle varArgCollectingInvocation = createConvertingInvocation(collectArguments(fixTarget,
219 argsLen), linkerServices, callSiteType);
221 // Is call site type assignable from an array type (e.g. Object:int[], or Object[]:String[])
222 final boolean isAssignableFromArray = callSiteLastArgType.isAssignableFrom(varArgType);
223 // Do we have a custom conversion that can potentially convert the call site type to an array?
224 final boolean isCustomConvertible = linkerServices.canConvert(callSiteLastArgType, varArgType);
225 if(!isAssignableFromArray && !isCustomConvertible) {
226 // Call site signature guarantees the argument can definitely not be converted to an array (i.e. it is
227 // primitive), and no conversion can help with it either. Link immediately to a vararg-packing method
228 // handle.
229 return varArgCollectingInvocation;
230 }
232 // This method handle employs language-specific conversions to convert the last argument into an array of
233 // vararg type.
234 final MethodHandle arrayConvertingInvocation = createConvertingInvocation(MethodHandles.filterArguments(
235 fixTarget, fixParamsLen, linkerServices.getTypeConverter(callSiteLastArgType, varArgType)),
236 linkerServices, callSiteType);
238 // This method handle determines whether the value can be converted to the array of vararg type using a
239 // language-specific conversion.
240 final MethodHandle canConvertArgToArray = MethodHandles.insertArguments(CAN_CONVERT_TO, 0, linkerServices,
241 varArgType);
243 // This one adjusts the previous one for the location of the argument and the call site type.
244 final MethodHandle canConvertLastArgToArray = MethodHandles.dropArguments(canConvertArgToArray, 0,
245 MethodType.genericMethodType(fixParamsLen).parameterList()).asType(callSiteType.changeReturnType(boolean.class));
247 // This one takes the previous ones and combines them into a method handle that converts the argument into
248 // a vararg array when it can, otherwise falls back to the vararg packer.
249 final MethodHandle convertToArrayWhenPossible = MethodHandles.guardWithTest(canConvertLastArgToArray,
250 arrayConvertingInvocation, varArgCollectingInvocation);
252 if(isAssignableFromArray) {
253 return MethodHandles.guardWithTest(
254 // Is incoming parameter already a compatible array?
255 Guards.isInstance(varArgType, fixParamsLen, callSiteType),
256 // Yes: just pass it to the method
257 createConvertingInvocation(fixTarget, linkerServices, callSiteType),
258 // No: either go through a custom conversion, or if it is not possible, go directly to the
259 // vararg packer.
260 isCustomConvertible ? convertToArrayWhenPossible : varArgCollectingInvocation);
261 }
263 // Just do the custom conversion with fallback to the vararg packer logic.
264 assert isCustomConvertible;
265 return convertToArrayWhenPossible;
266 }
268 // Remaining case: more than one vararg.
269 return createConvertingInvocation(collectArguments(fixTarget, argsLen), linkerServices, callSiteType);
270 }
272 @SuppressWarnings("unused")
273 private static boolean canConvertTo(final LinkerServices linkerServices, final Class<?> to, final Object obj) {
274 return obj == null ? false : linkerServices.canConvert(obj.getClass(), to);
275 }
277 /**
278 * Creates a method handle out of the original target that will collect the varargs for the exact component type of
279 * the varArg array. Note that this will nicely trigger language-specific type converters for exactly those varargs
280 * for which it is necessary when later passed to linkerServices.convertArguments().
281 *
282 * @param target the original method handle
283 * @param parameterCount the total number of arguments in the new method handle
284 * @return a collecting method handle
285 */
286 static MethodHandle collectArguments(final MethodHandle target, final int parameterCount) {
287 final MethodType methodType = target.type();
288 final int fixParamsLen = methodType.parameterCount() - 1;
289 final Class<?> arrayType = methodType.parameterType(fixParamsLen);
290 return target.asCollector(arrayType, parameterCount - fixParamsLen);
291 }
293 private static MethodHandle createConvertingInvocation(final MethodHandle sizedMethod,
294 final LinkerServices linkerServices, final MethodType callSiteType) {
295 return linkerServices.asTypeLosslessReturn(sizedMethod, callSiteType);
296 }
298 private static boolean typeMatchesDescription(final String paramTypes, final MethodType type) {
299 final StringTokenizer tok = new StringTokenizer(paramTypes, ", ");
300 for(int i = 1; i < type.parameterCount(); ++i) { // i = 1 as we ignore the receiver
301 if(!(tok.hasMoreTokens() && typeNameMatches(tok.nextToken(), type.parameterType(i)))) {
302 return false;
303 }
304 }
305 return !tok.hasMoreTokens();
306 }
308 private static boolean typeNameMatches(final String typeName, final Class<?> type) {
309 return typeName.equals(typeName.indexOf('.') == -1 ? type.getSimpleName() : type.getCanonicalName());
310 }
311 }