diff -r 000000000000 -r b1a7da25b547 src/jdk/internal/dynalink/beans/SingleDynamicMethod.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/jdk/internal/dynalink/beans/SingleDynamicMethod.java Wed Apr 27 01:36:41 2016 +0800 @@ -0,0 +1,305 @@ +/* + * 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 + * under the terms of the GNU General Public License version 2 only, as + * 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. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * 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.internal.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.internal.dynalink.CallSiteDescriptor; +import jdk.internal.dynalink.linker.LinkerServices; +import jdk.internal.dynalink.support.Guards; +import jdk.internal.dynalink.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). + * @author Attila Szegedi + * @version $Id: $ + */ +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(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 lookup, returns a method handle to this method's target. + * @param lookup the lookup to use. + * @return the handle to this method's target method. + */ + abstract MethodHandle getTarget(MethodHandles.Lookup lookup); + + @Override + MethodHandle getInvocation(CallSiteDescriptor callSiteDescriptor, LinkerServices linkerServices) { + return getInvocation(getTarget(callSiteDescriptor.getLookup()), callSiteDescriptor.getMethodType(), + linkerServices); + } + + @Override + SingleDynamicMethod getMethodForExactParamTypes(String paramTypes) { + return typeMatchesDescription(paramTypes, getMethodType()) ? this : null; + } + + @Override + boolean contains(SingleDynamicMethod method) { + return getMethodType().parameterList().equals(method.getMethodType().parameterList()); + } + + static String getMethodNameWithSignature(MethodType type, String methodName) { + final String typeStr = type.toString(); + final int retTypeIndex = typeStr.lastIndexOf(')') + 1; + int secondParamIndex = typeStr.indexOf(',') + 1; + if(secondParamIndex == 0) { + secondParamIndex = retTypeIndex - 1; + } + return typeStr.substring(retTypeIndex) + " " + methodName + "(" + typeStr.substring(secondParamIndex, retTypeIndex); + } + + /** + * 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. + * @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(MethodHandle target, MethodType callSiteType, LinkerServices linkerServices) { + final MethodType methodType = target.type(); + final int paramsLen = methodType.parameterCount(); + final boolean varArgs = target.isVarargsCollector(); + final MethodHandle fixTarget = varArgs ? target.asFixedArity() : target; + 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(target, 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, Class to, 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(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.asType(sizedMethod, callSiteType); + } + + private static boolean typeMatchesDescription(String paramTypes, 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(String typeName, Class type) { + return typeName.equals(typeName.indexOf('.') == -1 ? type.getSimpleName() : type.getCanonicalName()); + } +}