| /* |
| * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
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| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
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| * questions. |
| */ |
| |
| /* |
| * This file is available under and governed by the GNU General Public |
| * License version 2 only, as published by the Free Software Foundation. |
| * However, the following notice accompanied the original version of this |
| * file, and Oracle licenses the original version of this file under the BSD |
| * license: |
| */ |
| /* |
| Copyright 2009-2013 Attila Szegedi |
| |
| Licensed under both the Apache License, Version 2.0 (the "Apache License") |
| and the BSD License (the "BSD License"), with licensee being free to |
| choose either of the two at their discretion. |
| |
| You may not use this file except in compliance with either the Apache |
| License or the BSD License. |
| |
| If you choose to use this file in compliance with the Apache License, the |
| following notice applies to you: |
| |
| You may obtain a copy of the Apache License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |
| implied. See the License for the specific language governing |
| permissions and limitations under the License. |
| |
| If you choose to use this file in compliance with the BSD License, the |
| following notice applies to you: |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are |
| met: |
| * Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| * Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| * Neither the name of the copyright holder nor the names of |
| contributors may be used to endorse or promote products derived from |
| this software without specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
| IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
| PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER |
| BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR |
| BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package jdk.dynalink.beans; |
| |
| import java.lang.invoke.MethodHandle; |
| import java.lang.invoke.MethodHandles; |
| import java.lang.invoke.MethodType; |
| import java.lang.reflect.Array; |
| import java.util.StringTokenizer; |
| import jdk.dynalink.CallSiteDescriptor; |
| import jdk.dynalink.linker.LinkerServices; |
| import jdk.dynalink.linker.support.Guards; |
| import jdk.dynalink.linker.support.Lookup; |
| |
| /** |
| * Base class for dynamic methods that dispatch to a single target Java method or constructor. Handles adaptation of the |
| * target method to a call site type (including mapping variable arity methods to a call site signature with different |
| * arity). |
| */ |
| abstract class SingleDynamicMethod extends DynamicMethod { |
| private static final MethodHandle CAN_CONVERT_TO = Lookup.findOwnStatic(MethodHandles.lookup(), "canConvertTo", boolean.class, LinkerServices.class, Class.class, Object.class); |
| |
| SingleDynamicMethod(final String name) { |
| super(name); |
| } |
| |
| /** |
| * Returns true if this method is variable arity. |
| * @return true if this method is variable arity. |
| */ |
| abstract boolean isVarArgs(); |
| |
| /** |
| * Returns this method's native type. |
| * @return this method's native type. |
| */ |
| abstract MethodType getMethodType(); |
| |
| /** |
| * Given a specified call site descriptor, returns a method handle to this method's target. The target |
| * should only depend on the descriptor's lookup, and it should only retrieve it (as a privileged |
| * operation) when it is absolutely needed. |
| * @param desc the call site descriptor to use. |
| * @return the handle to this method's target method. |
| */ |
| abstract MethodHandle getTarget(CallSiteDescriptor desc); |
| |
| @Override |
| MethodHandle getInvocation(final CallSiteDescriptor callSiteDescriptor, final LinkerServices linkerServices) { |
| return linkerServices.getWithLookup(()->getInvocation(getTarget(callSiteDescriptor), |
| callSiteDescriptor.getMethodType(), linkerServices), callSiteDescriptor); |
| } |
| |
| @Override |
| SingleDynamicMethod getMethodForExactParamTypes(final String paramTypes) { |
| return typeMatchesDescription(paramTypes, getMethodType()) ? this : null; |
| } |
| |
| @Override |
| boolean contains(final SingleDynamicMethod method) { |
| return getMethodType().parameterList().equals(method.getMethodType().parameterList()); |
| } |
| |
| static String getMethodNameWithSignature(final MethodType type, final String methodName, final boolean withReturnType) { |
| final String typeStr = type.toString(); |
| final int retTypeIndex = typeStr.lastIndexOf(')') + 1; |
| int secondParamIndex = typeStr.indexOf(',') + 1; |
| if(secondParamIndex == 0) { |
| secondParamIndex = retTypeIndex - 1; |
| } |
| final StringBuilder b = new StringBuilder(); |
| if (withReturnType) { |
| b.append(typeStr, retTypeIndex, typeStr.length()).append(' '); |
| } |
| return b.append(methodName).append('(').append(typeStr, secondParamIndex, retTypeIndex).toString(); |
| } |
| |
| /** |
| * Given a method handle and a call site type, adapts the method handle to the call site type. Performs type |
| * conversions as needed using the specified linker services, and in case that the method handle is a vararg |
| * collector, matches it to the arity of the call site. The type of the return value is only changed if it can be |
| * converted using a conversion that loses neither precision nor magnitude, see |
| * {@link LinkerServices#asTypeLosslessReturn(MethodHandle, MethodType)}. |
| * @param target the method handle to adapt |
| * @param callSiteType the type of the call site |
| * @param linkerServices the linker services used for type conversions |
| * @return the adapted method handle. |
| */ |
| static MethodHandle getInvocation(final MethodHandle target, final MethodType callSiteType, final LinkerServices linkerServices) { |
| final MethodHandle filteredTarget = linkerServices.filterInternalObjects(target); |
| final MethodType methodType = filteredTarget.type(); |
| final int paramsLen = methodType.parameterCount(); |
| final boolean varArgs = target.isVarargsCollector(); |
| final MethodHandle fixTarget = varArgs ? filteredTarget.asFixedArity() : filteredTarget; |
| final int fixParamsLen = varArgs ? paramsLen - 1 : paramsLen; |
| final int argsLen = callSiteType.parameterCount(); |
| if(argsLen < fixParamsLen) { |
| // Less actual arguments than number of fixed declared arguments; can't invoke. |
| return null; |
| } |
| // Method handle has the same number of fixed arguments as the call site type |
| if(argsLen == fixParamsLen) { |
| // Method handle that matches the number of actual arguments as the number of fixed arguments |
| final MethodHandle matchedMethod; |
| if(varArgs) { |
| // If vararg, add a zero-length array of the expected type as the last argument to signify no variable |
| // arguments. |
| matchedMethod = MethodHandles.insertArguments(fixTarget, fixParamsLen, Array.newInstance( |
| methodType.parameterType(fixParamsLen).getComponentType(), 0)); |
| } else { |
| // Otherwise, just use the method |
| matchedMethod = fixTarget; |
| } |
| return createConvertingInvocation(matchedMethod, linkerServices, callSiteType); |
| } |
| |
| // What's below only works for varargs |
| if(!varArgs) { |
| return null; |
| } |
| |
| final Class<?> varArgType = methodType.parameterType(fixParamsLen); |
| // Handle a somewhat sinister corner case: caller passes exactly one argument in the vararg position, and we |
| // must handle both a prepacked vararg array as well as a genuine 1-long vararg sequence. |
| if(argsLen == paramsLen) { |
| final Class<?> callSiteLastArgType = callSiteType.parameterType(fixParamsLen); |
| if(varArgType.isAssignableFrom(callSiteLastArgType)) { |
| // Call site signature guarantees we'll always be passed a single compatible array; just link directly |
| // to the method, introducing necessary conversions. Also, preserve it being a variable arity method. |
| return createConvertingInvocation(filteredTarget, linkerServices, callSiteType).asVarargsCollector( |
| callSiteLastArgType); |
| } |
| |
| // This method handle takes the single argument and packs it into a newly allocated single-element array. It |
| // will be used when the incoming argument can't be converted to the vararg array type (the "vararg packer" |
| // method). |
| final MethodHandle varArgCollectingInvocation = createConvertingInvocation(collectArguments(fixTarget, |
| argsLen), linkerServices, callSiteType); |
| |
| // Is call site type assignable from an array type (e.g. Object:int[], or Object[]:String[]) |
| final boolean isAssignableFromArray = callSiteLastArgType.isAssignableFrom(varArgType); |
| // Do we have a custom conversion that can potentially convert the call site type to an array? |
| final boolean isCustomConvertible = linkerServices.canConvert(callSiteLastArgType, varArgType); |
| if(!isAssignableFromArray && !isCustomConvertible) { |
| // Call site signature guarantees the argument can definitely not be converted to an array (i.e. it is |
| // primitive), and no conversion can help with it either. Link immediately to a vararg-packing method |
| // handle. |
| return varArgCollectingInvocation; |
| } |
| |
| // This method handle employs language-specific conversions to convert the last argument into an array of |
| // vararg type. |
| final MethodHandle arrayConvertingInvocation = createConvertingInvocation(MethodHandles.filterArguments( |
| fixTarget, fixParamsLen, linkerServices.getTypeConverter(callSiteLastArgType, varArgType)), |
| linkerServices, callSiteType); |
| |
| // This method handle determines whether the value can be converted to the array of vararg type using a |
| // language-specific conversion. |
| final MethodHandle canConvertArgToArray = MethodHandles.insertArguments(CAN_CONVERT_TO, 0, linkerServices, |
| varArgType); |
| |
| // This one adjusts the previous one for the location of the argument and the call site type. |
| final MethodHandle canConvertLastArgToArray = MethodHandles.dropArguments(canConvertArgToArray, 0, |
| MethodType.genericMethodType(fixParamsLen).parameterList()).asType(callSiteType.changeReturnType(boolean.class)); |
| |
| // This one takes the previous ones and combines them into a method handle that converts the argument into |
| // a vararg array when it can, otherwise falls back to the vararg packer. |
| final MethodHandle convertToArrayWhenPossible = MethodHandles.guardWithTest(canConvertLastArgToArray, |
| arrayConvertingInvocation, varArgCollectingInvocation); |
| |
| if(isAssignableFromArray) { |
| return MethodHandles.guardWithTest( |
| // Is incoming parameter already a compatible array? |
| Guards.isInstance(varArgType, fixParamsLen, callSiteType), |
| // Yes: just pass it to the method |
| createConvertingInvocation(fixTarget, linkerServices, callSiteType), |
| // No: either go through a custom conversion, or if it is not possible, go directly to the |
| // vararg packer. |
| isCustomConvertible ? convertToArrayWhenPossible : varArgCollectingInvocation); |
| } |
| |
| // Just do the custom conversion with fallback to the vararg packer logic. |
| assert isCustomConvertible; |
| return convertToArrayWhenPossible; |
| } |
| |
| // Remaining case: more than one vararg. |
| return createConvertingInvocation(collectArguments(fixTarget, argsLen), linkerServices, callSiteType); |
| } |
| |
| @SuppressWarnings("unused") |
| private static boolean canConvertTo(final LinkerServices linkerServices, final Class<?> to, final Object obj) { |
| return obj == null ? false : linkerServices.canConvert(obj.getClass(), to); |
| } |
| |
| /** |
| * Creates a method handle out of the original target that will collect the varargs for the exact component type of |
| * the varArg array. Note that this will nicely trigger language-specific type converters for exactly those varargs |
| * for which it is necessary when later passed to linkerServices.convertArguments(). |
| * |
| * @param target the original method handle |
| * @param parameterCount the total number of arguments in the new method handle |
| * @return a collecting method handle |
| */ |
| static MethodHandle collectArguments(final MethodHandle target, final int parameterCount) { |
| final MethodType methodType = target.type(); |
| final int fixParamsLen = methodType.parameterCount() - 1; |
| final Class<?> arrayType = methodType.parameterType(fixParamsLen); |
| return target.asCollector(arrayType, parameterCount - fixParamsLen); |
| } |
| |
| private static MethodHandle createConvertingInvocation(final MethodHandle sizedMethod, |
| final LinkerServices linkerServices, final MethodType callSiteType) { |
| return linkerServices.asTypeLosslessReturn(sizedMethod, callSiteType); |
| } |
| |
| private static boolean typeMatchesDescription(final String paramTypes, final MethodType type) { |
| final StringTokenizer tok = new StringTokenizer(paramTypes, ", "); |
| for(int i = 1; i < type.parameterCount(); ++i) { // i = 1 as we ignore the receiver |
| if(!(tok.hasMoreTokens() && typeNameMatches(tok.nextToken(), type.parameterType(i)))) { |
| return false; |
| } |
| } |
| return !tok.hasMoreTokens(); |
| } |
| |
| private static boolean typeNameMatches(final String typeName, final Class<?> type) { |
| return typeName.equals(typeName.indexOf('.') == -1 ? type.getSimpleName() : type.getCanonicalName()); |
| } |
| } |