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  */

    25 

    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

    35 

    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.

    39 

    40    You may not use this file except in compliance with either the Apache

    41    License or the BSD License.

    42 

    43    If you choose to use this file in compliance with the Apache License, the

    44    following notice applies to you:

    45 

    46        You may obtain a copy of the Apache License at

    47 

    48            http://www.apache.org/licenses/LICENSE-2.0

    49 

    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.

    55 

    56    If you choose to use this file in compliance with the BSD License, the

    57    following notice applies to you:

    58 

    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.

    70 

    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 */

    83 

    84 package jdk.internal.dynalink.beans;

    85 

    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 

    95 /**

    96  * Base class for dynamic methods that dispatch to a single target Java method or constructor. Handles adaptation of the

    97  * target method to a call site type (including mapping variable arity methods to a call site signature with different

    98  * arity).

    99  * @author Attila Szegedi

   100  * @version $Id: $

   101  */

   102 abstract class SingleDynamicMethod extends DynamicMethod {

   103     SingleDynamicMethod(String name) {

   104         super(name);

   105     }

   106 

   107     /**

   108      * Returns true if this method is variable arity.

   109      * @return true if this method is variable arity.

   110      */

   111     abstract boolean isVarArgs();

   112 

   113     /**

   114      * Returns this method's native type.

   115      * @return this method's native type.

   116      */

   117     abstract MethodType getMethodType();

   118 

   119     /**

   120      * Given a specified lookup, returns a method handle to this method's target.

   121      * @param lookup the lookup to use.

   122      * @return the handle to this method's target method.

   123      */

   124     abstract MethodHandle getTarget(MethodHandles.Lookup lookup);

   125 

   126     @Override

   127     MethodHandle getInvocation(CallSiteDescriptor callSiteDescriptor, LinkerServices linkerServices) {

   128         return getInvocation(getTarget(callSiteDescriptor.getLookup()), callSiteDescriptor.getMethodType(),

   129                 linkerServices);

   130     }

   131 

   132     @Override

   133     SingleDynamicMethod getMethodForExactParamTypes(String paramTypes) {

   134         return typeMatchesDescription(paramTypes, getMethodType()) ? this : null;

   135     }

   136 

   137     @Override

   138     boolean contains(SingleDynamicMethod method) {

   139         return getMethodType().parameterList().equals(method.getMethodType().parameterList());

   140     }

   141 

   142     static String getMethodNameWithSignature(MethodType type, String methodName) {

   143         final String typeStr = type.toString();

   144         final int retTypeIndex = typeStr.lastIndexOf(')') + 1;

   145         int secondParamIndex = typeStr.indexOf(',') + 1;

   146         if(secondParamIndex == 0) {

   147             secondParamIndex = retTypeIndex - 1;

   148         }

   149         return typeStr.substring(retTypeIndex) + " " + methodName + "(" + typeStr.substring(secondParamIndex, retTypeIndex);

   150     }

   151 

   152     /**

   153      * Given a method handle and a call site type, adapts the method handle to the call site type. Performs type

   154      * conversions as needed using the specified linker services, and in case that the method handle is a vararg

   155      * collector, matches it to the arity of the call site.

   156      * @param target the method handle to adapt

   157      * @param callSiteType the type of the call site

   158      * @param linkerServices the linker services used for type conversions

   159      * @return the adapted method handle.

   160      */

   161     static MethodHandle getInvocation(MethodHandle target, MethodType callSiteType, LinkerServices linkerServices) {

   162         final MethodType methodType = target.type();

   163         final int paramsLen = methodType.parameterCount();

   164         final boolean varArgs = target.isVarargsCollector();

   165         final MethodHandle fixTarget = varArgs ? target.asFixedArity() : target;

   166         final int fixParamsLen = varArgs ? paramsLen - 1 : paramsLen;

   167         final int argsLen = callSiteType.parameterCount();

   168         if(argsLen < fixParamsLen) {

   169             // Less actual arguments than number of fixed declared arguments; can't invoke.

   170             return null;

   171         }

   172         // Method handle has the same number of fixed arguments as the call site type

   173         if(argsLen == fixParamsLen) {

   174             // Method handle that matches the number of actual arguments as the number of fixed arguments

   175             final MethodHandle matchedMethod;

   176             if(varArgs) {

   177                 // If vararg, add a zero-length array of the expected type as the last argument to signify no variable

   178                 // arguments.

   179                 matchedMethod = MethodHandles.insertArguments(fixTarget, fixParamsLen, Array.newInstance(

   180                         methodType.parameterType(fixParamsLen).getComponentType(), 0));

   181             } else {

   182                 // Otherwise, just use the method

   183                 matchedMethod = fixTarget;

   184             }

   185             return createConvertingInvocation(matchedMethod, linkerServices, callSiteType);

   186         }

   187 

   188         // What's below only works for varargs

   189         if(!varArgs) {

   190             return null;

   191         }

   192 

   193         final Class<?> varArgType = methodType.parameterType(fixParamsLen);

   194         // Handle a somewhat sinister corner case: caller passes exactly one argument in the vararg position, and we

   195         // must handle both a prepacked vararg array as well as a genuine 1-long vararg sequence.

   196         if(argsLen == paramsLen) {

   197             final Class<?> callSiteLastArgType = callSiteType.parameterType(fixParamsLen);

   198             if(varArgType.isAssignableFrom(callSiteLastArgType)) {

   199                 // Call site signature guarantees we'll always be passed a single compatible array; just link directly

   200                 // to the method, introducing necessary conversions. Also, preserve it being a variable arity method.

   201                 return createConvertingInvocation(target, linkerServices, callSiteType).asVarargsCollector(

   202                         callSiteLastArgType);

   203             }

   204             if(!linkerServices.canConvert(callSiteLastArgType, varArgType)) {

   205                 // Call site signature guarantees the argument can definitely not be an array (i.e. it is primitive);

   206                 // link immediately to a vararg-packing method handle.

   207                 return createConvertingInvocation(collectArguments(fixTarget, argsLen), linkerServices, callSiteType);

   208             }

   209             // Call site signature makes no guarantees that the single argument in the vararg position will be

   210             // compatible across all invocations. Need to insert an appropriate guard and fall back to generic vararg

   211             // method when it is not.

   212             return MethodHandles.guardWithTest(Guards.isInstance(varArgType, fixParamsLen, callSiteType),

   213                     createConvertingInvocation(fixTarget, linkerServices, callSiteType),

   214                     createConvertingInvocation(collectArguments(fixTarget, argsLen), linkerServices, callSiteType));

   215         }

   216 

   217         // Remaining case: more than one vararg.

   218         return createConvertingInvocation(collectArguments(fixTarget, argsLen), linkerServices, callSiteType);

   219     }

   220 

   221     /**

   222      * Creates a method handle out of the original target that will collect the varargs for the exact component type of

   223      * the varArg array. Note that this will nicely trigger language-specific type converters for exactly those varargs

   224      * for which it is necessary when later passed to linkerServices.convertArguments().

   225      *

   226      * @param target the original method handle

   227      * @param parameterCount the total number of arguments in the new method handle

   228      * @return a collecting method handle

   229      */

   230     static MethodHandle collectArguments(MethodHandle target, final int parameterCount) {

   231         final MethodType methodType = target.type();

   232         final int fixParamsLen = methodType.parameterCount() - 1;

   233         final Class<?> arrayType = methodType.parameterType(fixParamsLen);

   234         return target.asCollector(arrayType, parameterCount - fixParamsLen);

   235     }

   236 

   237     private static MethodHandle createConvertingInvocation(final MethodHandle sizedMethod,

   238             final LinkerServices linkerServices, final MethodType callSiteType) {

   239         return linkerServices.asType(sizedMethod, callSiteType);

   240     }

   241 

   242     private static boolean typeMatchesDescription(String paramTypes, MethodType type) {

   243         final StringTokenizer tok = new StringTokenizer(paramTypes, ", ");

   244         for(int i = 1; i < type.parameterCount(); ++i) { // i = 1 as we ignore the receiver

   245             if(!(tok.hasMoreTokens() && typeNameMatches(tok.nextToken(), type.parameterType(i)))) {

   246                 return false;

   247             }

   248         }

   249         return !tok.hasMoreTokens();

   250     }

   251 

   252     private static boolean typeNameMatches(String typeName, Class<?> type) {

   253         return  typeName.equals(typeName.indexOf('.') == -1 ? type.getSimpleName() : type.getCanonicalName());

   254     }

   255 }