| /* |
| * 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.linker; |
| |
| import java.lang.invoke.MethodHandle; |
| import java.lang.invoke.MethodHandles; |
| import java.lang.invoke.MethodType; |
| import jdk.internal.dynalink.DynamicLinker; |
| import jdk.internal.dynalink.DynamicLinkerFactory; |
| import jdk.internal.dynalink.linker.ConversionComparator.Comparison; |
| import jdk.internal.dynalink.support.TypeUtilities; |
| |
| /** |
| * Interface for services provided to {@link GuardingDynamicLinker} instances by the {@link DynamicLinker} that owns |
| * them. You can think of it as the interface of the {@link DynamicLinker} that faces the {@link GuardingDynamicLinker} |
| * s. |
| * |
| * @author Attila Szegedi |
| */ |
| public interface LinkerServices { |
| /** |
| * Similar to {@link MethodHandle#asType(MethodType)} except it also hooks in method handles produced by |
| * {@link GuardingTypeConverterFactory} implementations, providing for language-specific type coercing of |
| * parameters. It will apply {@link MethodHandle#asType(MethodType)} for all primitive-to-primitive, |
| * wrapper-to-primitive, primitive-to-wrapper conversions as well as for all upcasts. For all other conversions, |
| * it'll insert {@link MethodHandles#filterArguments(MethodHandle, int, MethodHandle...)} with composite filters |
| * provided by {@link GuardingTypeConverterFactory} implementations. |
| * |
| * @param handle target method handle |
| * @param fromType the types of source arguments |
| * @return a method handle that is a suitable combination of {@link MethodHandle#asType(MethodType)}, |
| * {@link MethodHandles#filterArguments(MethodHandle, int, MethodHandle...)}, and |
| * {@link MethodHandles#filterReturnValue(MethodHandle, MethodHandle)} with |
| * {@link GuardingTypeConverterFactory}-produced type converters as filters. |
| */ |
| public MethodHandle asType(MethodHandle handle, MethodType fromType); |
| |
| /** |
| * Similar to {@link #asType(MethodHandle, MethodType)} except it only converts the return type of the method handle |
| * when it can be done using a conversion that loses neither precision nor magnitude, otherwise it leaves it |
| * unchanged. The idea is that other conversions should not be performed by individual linkers, but instead the |
| * {@link DynamicLinkerFactory#setPrelinkFilter(jdk.internal.dynalink.GuardedInvocationFilter) pre-link filter of |
| * the dynamic linker} should implement the strategy of dealing with potentially lossy return type conversions in a |
| * manner specific to the language runtime. |
| * |
| * @param handle target method handle |
| * @param fromType the types of source arguments |
| * @return a method handle that is a suitable combination of {@link MethodHandle#asType(MethodType)}, and |
| * {@link MethodHandles#filterArguments(MethodHandle, int, MethodHandle...)} with |
| * {@link GuardingTypeConverterFactory}-produced type converters as filters. |
| */ |
| public MethodHandle asTypeLosslessReturn(MethodHandle handle, MethodType fromType); |
| |
| /** |
| * Given a source and target type, returns a method handle that converts between them. Never returns null; in worst |
| * case it will return an identity conversion (that might fail for some values at runtime). You rarely need to use |
| * this method directly; you should mostly rely on {@link #asType(MethodHandle, MethodType)} instead. You really |
| * only need this method if you have a piece of your program that is written in Java, and you need to reuse existing |
| * type conversion machinery in a non-invokedynamic context. |
| * @param sourceType the type to convert from |
| * @param targetType the type to convert to |
| * @return a method handle performing the conversion. |
| */ |
| public MethodHandle getTypeConverter(Class<?> sourceType, Class<?> targetType); |
| |
| /** |
| * Returns true if there might exist a conversion between the requested types (either an automatic JVM conversion, |
| * or one provided by any available {@link GuardingTypeConverterFactory}), or false if there definitely does not |
| * exist a conversion between the requested types. Note that returning true does not guarantee that the conversion |
| * will succeed at runtime (notably, if the "from" or "to" types are sufficiently generic), but returning false |
| * guarantees that it would fail. |
| * |
| * @param from the source type for the conversion |
| * @param to the target type for the conversion |
| * @return true if there can be a conversion, false if there can not. |
| */ |
| public boolean canConvert(Class<?> from, Class<?> to); |
| |
| /** |
| * Creates a guarded invocation using the {@link DynamicLinker} that exposes this linker services interface. Linkers |
| * can typically use them to delegate linking of wrapped objects. |
| * |
| * @param linkRequest a request for linking the invocation |
| * @return a guarded invocation linked by the top-level linker (or any of its delegates). Can be null if no |
| * available linker is able to link the invocation. |
| * @throws Exception in case the top-level linker throws an exception |
| */ |
| public GuardedInvocation getGuardedInvocation(LinkRequest linkRequest) throws Exception; |
| |
| /** |
| * Determines which of the two type conversions from a source type to the two target types is preferred. This is |
| * used for dynamic overloaded method resolution. If the source type is convertible to exactly one target type with |
| * a method invocation conversion, it is chosen, otherwise available {@link ConversionComparator}s are consulted. |
| * @param sourceType the source type. |
| * @param targetType1 one potential target type |
| * @param targetType2 another potential target type. |
| * @return one of Comparison constants that establish which - if any - of the target types is preferable for the |
| * conversion. |
| */ |
| public Comparison compareConversion(Class<?> sourceType, Class<?> targetType1, Class<?> targetType2); |
| |
| /** |
| * Modifies the method handle so that any parameters that can receive potentially internal language runtime objects |
| * will have a filter added on them to prevent them from escaping, potentially by wrapping them. |
| * It can also potentially add an unwrapping filter to the return value. |
| * @param target the target method handle |
| * @return a method handle with parameters and/or return type potentially filtered for wrapping and unwrapping. |
| */ |
| public MethodHandle filterInternalObjects(final MethodHandle target); |
| |
| /** |
| * If we could just use Java 8 constructs, then {@code asTypeSafeReturn} would be a method with default |
| * implementation. Since we can't do that, we extract common default implementations into this static class. |
| */ |
| public static class Implementation { |
| /** |
| * Default implementation for {@link LinkerServices#asTypeLosslessReturn(MethodHandle, MethodType)}. |
| * @param linkerServices the linker services that delegates to this implementation |
| * @param handle the passed handle |
| * @param fromType the passed type |
| * @return the converted method handle, as per the {@code asTypeSafeReturn} semantics. |
| */ |
| public static MethodHandle asTypeLosslessReturn(final LinkerServices linkerServices, final MethodHandle handle, final MethodType fromType) { |
| final Class<?> handleReturnType = handle.type().returnType(); |
| return linkerServices.asType(handle, TypeUtilities.isConvertibleWithoutLoss(handleReturnType, fromType.returnType()) ? |
| fromType : fromType.changeReturnType(handleReturnType)); |
| } |
| } |
| } |
