| /* |
| * 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 |
| |
| 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.linker; |
| |
| import java.lang.invoke.MethodHandle; |
| import java.lang.invoke.MethodHandles; |
| import java.lang.invoke.MethodType; |
| import java.util.function.Supplier; |
| import jdk.dynalink.DynamicLinker; |
| import jdk.dynalink.DynamicLinkerFactory; |
| import jdk.dynalink.SecureLookupSupplier; |
| import jdk.dynalink.linker.ConversionComparator.Comparison; |
| import jdk.dynalink.linker.support.TypeUtilities; |
| |
| /** |
| * Interface for services provided to {@link GuardingDynamicLinker} instances by |
| * the {@link DynamicLinker} that owns them. |
| */ |
| public interface LinkerServices { |
| /** |
| * Similar to {@link MethodHandle#asType(MethodType)} except it also hooks |
| * in method handles produced by all available |
| * {@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 treats |
| * return value type conversion specially. 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. These |
| * are the only return value conversions that should be performed by |
| * individual language-specific linkers, and |
| * {@link DynamicLinkerFactory#setPrelinkTransformer(GuardedInvocationTransformer) |
| * pre-link transformer of the dynamic linker} should implement the strategy |
| * for dealing with potentially lossy return type conversions in a manner |
| * specific to the language runtime where the call site is located. |
| * |
| * @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 default MethodHandle asTypeLosslessReturn(final MethodHandle handle, final MethodType fromType) { |
| final Class<?> handleReturnType = handle.type().returnType(); |
| return asType(handle, TypeUtilities.isConvertibleWithoutLoss(handleReturnType, fromType.returnType()) ? |
| fromType : fromType.changeReturnType(handleReturnType)); |
| } |
| |
| /** |
| * 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 and should mostly rely on |
| * {@link #asType(MethodHandle, MethodType)} instead. This method is needed |
| * when you need to reuse existing type conversion machinery outside the |
| * context of processing a link request. |
| * @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 for all values (especially 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 delegating back to the {@link DynamicLinker} |
| * that exposes this linker services object. The dynamic linker will then |
| * itself delegate the linking to all of its managed |
| * {@link GuardingDynamicLinker}s including potentially this one if no |
| * linker responds earlier, so beware of infinite recursion. You'll |
| * typically craft the link request so that it will be different than the |
| * one you are currently trying to link. |
| * |
| * @param linkRequest a request for linking the invocation |
| * @return a guarded invocation linked by some of the guarding dynamic |
| * linkers managed by the top-level dynamic linker. Can be null if no |
| * available linker is able to link the invocation. You will typically use |
| * the elements of the returned invocation to compose your own 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. Basically |
| * transforms the method handle using the transformer configured by |
| * {@link DynamicLinkerFactory#setInternalObjectsFilter(MethodHandleTransformer)}. |
| * @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); |
| |
| /** |
| * Executes an operation within the context of a particular |
| * {@code MethodHandles.Lookup} lookup object. Normally, methods on |
| * {@code LinkerServices} are invoked as part of the linking mechanism in |
| * which case Dynalink internally maintains a per-thread current lookup |
| * (the one belonging to the descriptor of the call site being linked). This |
| * lookup can be retrieved by any {@link GuardingTypeConverterFactory} |
| * involved in linking if it needs to generate lookup-sensitive converters. |
| * However, linker services' methods can be invoked outside the linking |
| * process too when implementing invocation-time dispatch schemes, invoking |
| * conversions at runtime, etc. If it becomes necessary to use any type |
| * converter in this situation, and it needs a lookup, it will normally only |
| * get {@link MethodHandles#publicLookup()} as the thread is not engaged in |
| * a linking operation. If there is a way to meaningfully associate the |
| * operation to the context of some caller class, consider performing it |
| * within an invocation of this method and passing a full-strength lookup |
| * for that class, as it will associate that lookup with the current thread |
| * for the duration of the operation. Note that since you are passing a |
| * {@link SecureLookupSupplier}, any invoked type converter factories will |
| * still need to hold the necessary runtime permission to be able to get the |
| * lookup should they need it. |
| * @param <T> the type of the return value provided by the passed-in supplier. |
| * @param operation the operation to execute in context of the specified lookup. |
| * @param lookupSupplier secure supplier of the lookup |
| * @return the return value of the action |
| * @throws NullPointerException if either action or lookupSupplier are null. |
| * @see GuardingTypeConverterFactory#convertToType(Class, Class, Supplier) |
| */ |
| public <T> T getWithLookup(final Supplier<T> operation, final SecureLookupSupplier lookupSupplier); |
| } |