| /* |
| * Copyright (c) 2010, 2016, 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.dynalink; |
| |
| import java.lang.invoke.MethodHandle; |
| import java.lang.invoke.MethodHandles; |
| import java.lang.invoke.MethodHandles.Lookup; |
| import java.lang.invoke.MethodType; |
| import java.lang.invoke.WrongMethodTypeException; |
| import java.security.AccessControlContext; |
| import java.security.AccessController; |
| import java.security.PrivilegedAction; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.function.Supplier; |
| import jdk.dynalink.internal.AccessControlContextFactory; |
| import jdk.dynalink.linker.ConversionComparator; |
| import jdk.dynalink.linker.ConversionComparator.Comparison; |
| import jdk.dynalink.linker.GuardedInvocation; |
| import jdk.dynalink.linker.GuardingTypeConverterFactory; |
| import jdk.dynalink.linker.LinkerServices; |
| import jdk.dynalink.linker.MethodTypeConversionStrategy; |
| import jdk.dynalink.linker.support.TypeUtilities; |
| |
| /** |
| * A factory for type converters. This class is the main implementation behind the |
| * {@link LinkerServices#asType(MethodHandle, MethodType)}. It manages the known {@link GuardingTypeConverterFactory} |
| * instances and creates appropriate converters for method handles. |
| */ |
| final class TypeConverterFactory { |
| private static final AccessControlContext GET_CLASS_LOADER_CONTEXT = |
| AccessControlContextFactory.createAccessControlContext("getClassLoader"); |
| |
| private final GuardingTypeConverterFactory[] factories; |
| private final ConversionComparator[] comparators; |
| private final MethodTypeConversionStrategy autoConversionStrategy; |
| |
| private final ClassValue<ClassMap<MethodHandle>> converterMap = new ClassValue<ClassMap<MethodHandle>>() { |
| @Override |
| protected ClassMap<MethodHandle> computeValue(final Class<?> sourceType) { |
| return new ClassMap<MethodHandle>(getClassLoader(sourceType)) { |
| @Override |
| protected MethodHandle computeValue(final Class<?> targetType) { |
| try { |
| return createConverter(sourceType, targetType); |
| } catch (final RuntimeException e) { |
| throw e; |
| } catch (final Exception e) { |
| throw new RuntimeException(e); |
| } |
| } |
| }; |
| } |
| }; |
| |
| private final ClassValue<ClassMap<MethodHandle>> converterIdentityMap = new ClassValue<ClassMap<MethodHandle>>() { |
| @Override |
| protected ClassMap<MethodHandle> computeValue(final Class<?> sourceType) { |
| return new ClassMap<MethodHandle>(getClassLoader(sourceType)) { |
| @Override |
| protected MethodHandle computeValue(final Class<?> targetType) { |
| if(!canAutoConvert(sourceType, targetType)) { |
| final MethodHandle converter = getCacheableTypeConverter(sourceType, targetType); |
| if(converter != IDENTITY_CONVERSION) { |
| return converter; |
| } |
| } |
| return IDENTITY_CONVERSION.asType(MethodType.methodType(targetType, sourceType)); |
| } |
| }; |
| } |
| }; |
| |
| private final ClassValue<ClassMap<Boolean>> canConvert = new ClassValue<ClassMap<Boolean>>() { |
| @Override |
| protected ClassMap<Boolean> computeValue(final Class<?> sourceType) { |
| return new ClassMap<Boolean>(getClassLoader(sourceType)) { |
| @Override |
| protected Boolean computeValue(final Class<?> targetType) { |
| try { |
| return getTypeConverterNull(sourceType, targetType) != null; |
| } catch (final RuntimeException e) { |
| throw e; |
| } catch (final Exception e) { |
| throw new RuntimeException(e); |
| } |
| } |
| }; |
| } |
| }; |
| |
| private static ClassLoader getClassLoader(final Class<?> clazz) { |
| return AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() { |
| @Override |
| public ClassLoader run() { |
| return clazz.getClassLoader(); |
| } |
| }, GET_CLASS_LOADER_CONTEXT); |
| } |
| |
| /** |
| * Creates a new type converter factory from the available {@link GuardingTypeConverterFactory} instances. |
| * |
| * @param factories the {@link GuardingTypeConverterFactory} instances to compose. |
| * @param autoConversionStrategy conversion strategy for automatic type conversions. After |
| * {@link #asType(java.lang.invoke.MethodHandle, java.lang.invoke.MethodType)} has applied all custom |
| * conversions to a method handle, it still needs to effect |
| * {@link TypeUtilities#isMethodInvocationConvertible(Class, Class) method invocation conversions} that |
| * can usually be automatically applied as per |
| * {@link java.lang.invoke.MethodHandle#asType(java.lang.invoke.MethodType)}. |
| * However, sometimes language runtimes will want to customize even those conversions for their own call |
| * sites. A typical example is allowing unboxing of null return values, which is by default prohibited by |
| * ordinary {@code MethodHandles.asType}. In this case, a language runtime can install its own custom |
| * automatic conversion strategy, that can deal with null values. Note that when the strategy's |
| * {@link MethodTypeConversionStrategy#asType(java.lang.invoke.MethodHandle, java.lang.invoke.MethodType)} |
| * is invoked, the custom language conversions will already have been applied to the method handle, so by |
| * design the difference between the handle's current method type and the desired final type will always |
| * only be ones that can be subjected to method invocation conversions. Can be null, in which case no |
| * custom strategy is employed. |
| */ |
| TypeConverterFactory(final Iterable<? extends GuardingTypeConverterFactory> factories, |
| final MethodTypeConversionStrategy autoConversionStrategy) { |
| final List<GuardingTypeConverterFactory> l = new LinkedList<>(); |
| final List<ConversionComparator> c = new LinkedList<>(); |
| for(final GuardingTypeConverterFactory factory: factories) { |
| l.add(factory); |
| if(factory instanceof ConversionComparator) { |
| c.add((ConversionComparator)factory); |
| } |
| } |
| this.factories = l.toArray(new GuardingTypeConverterFactory[0]); |
| this.comparators = c.toArray(new ConversionComparator[0]); |
| this.autoConversionStrategy = autoConversionStrategy; |
| } |
| |
| /** |
| * 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. For all conversions that are not a JLS method invocation conversion it'll insert |
| * {@link MethodHandles#filterArguments(MethodHandle, int, MethodHandle...)} with composite filters |
| * provided by {@link GuardingTypeConverterFactory} implementations. For the remaining JLS method invocation |
| * conversions, it will invoke {@link MethodTypeConversionStrategy#asType(MethodHandle, MethodType)} first |
| * if an automatic conversion strategy was specified in the |
| * {@link #TypeConverterFactory(Iterable, MethodTypeConversionStrategy) constructor}, and finally apply |
| * {@link MethodHandle#asType(MethodType)} for any remaining conversions. |
| * |
| * @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 MethodTypeConversionStrategy#asType(MethodHandle, MethodType)}, and |
| * {@link MethodHandles#filterArguments(MethodHandle, int, MethodHandle...)} with |
| * {@link GuardingTypeConverterFactory} produced type converters as filters. |
| */ |
| MethodHandle asType(final MethodHandle handle, final MethodType fromType) { |
| MethodHandle newHandle = handle; |
| final MethodType toType = newHandle.type(); |
| final int l = toType.parameterCount(); |
| if(l != fromType.parameterCount()) { |
| throw new WrongMethodTypeException("Parameter counts differ: " + handle.type() + " vs. " + fromType); |
| } |
| int pos = 0; |
| final List<MethodHandle> converters = new LinkedList<>(); |
| for(int i = 0; i < l; ++i) { |
| final Class<?> fromParamType = fromType.parameterType(i); |
| final Class<?> toParamType = toType.parameterType(i); |
| if(canAutoConvert(fromParamType, toParamType)) { |
| newHandle = applyConverters(newHandle, pos, converters); |
| } else { |
| final MethodHandle converter = getTypeConverterNull(fromParamType, toParamType); |
| if(converter != null) { |
| if(converters.isEmpty()) { |
| pos = i; |
| } |
| converters.add(converter); |
| } else { |
| newHandle = applyConverters(newHandle, pos, converters); |
| } |
| } |
| } |
| newHandle = applyConverters(newHandle, pos, converters); |
| |
| // Convert return type |
| final Class<?> fromRetType = fromType.returnType(); |
| final Class<?> toRetType = toType.returnType(); |
| if(fromRetType != Void.TYPE && toRetType != Void.TYPE) { |
| if(!canAutoConvert(toRetType, fromRetType)) { |
| final MethodHandle converter = getTypeConverterNull(toRetType, fromRetType); |
| if(converter != null) { |
| newHandle = MethodHandles.filterReturnValue(newHandle, converter); |
| } |
| } |
| } |
| |
| // Give change to automatic conversion strategy, if one is present. |
| final MethodHandle autoConvertedHandle = |
| autoConversionStrategy != null ? autoConversionStrategy.asType(newHandle, fromType) : newHandle; |
| |
| // Do a final asType for any conversions that remain. |
| return autoConvertedHandle.asType(fromType); |
| } |
| |
| private static MethodHandle applyConverters(final MethodHandle handle, final int pos, final List<MethodHandle> converters) { |
| if(converters.isEmpty()) { |
| return handle; |
| } |
| final MethodHandle newHandle = |
| MethodHandles.filterArguments(handle, pos, converters.toArray(new MethodHandle[0])); |
| converters.clear(); |
| return newHandle; |
| } |
| |
| /** |
| * 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. |
| */ |
| boolean canConvert(final Class<?> from, final Class<?> to) { |
| return canAutoConvert(from, to) || canConvert.get(from).get(to); |
| } |
| |
| /** |
| * 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. |
| */ |
| Comparison compareConversion(final Class<?> sourceType, final Class<?> targetType1, final Class<?> targetType2) { |
| for(final ConversionComparator comparator: comparators) { |
| final Comparison result = comparator.compareConversion(sourceType, targetType1, targetType2); |
| if(result != Comparison.INDETERMINATE) { |
| return result; |
| } |
| } |
| if(TypeUtilities.isMethodInvocationConvertible(sourceType, targetType1)) { |
| if(!TypeUtilities.isMethodInvocationConvertible(sourceType, targetType2)) { |
| return Comparison.TYPE_1_BETTER; |
| } |
| } else if(TypeUtilities.isMethodInvocationConvertible(sourceType, targetType2)) { |
| return Comparison.TYPE_2_BETTER; |
| } |
| return Comparison.INDETERMINATE; |
| } |
| |
| /** |
| * Determines whether it's safe to perform an automatic conversion between the source and target class. |
| * |
| * @param fromType convert from this class |
| * @param toType convert to this class |
| * @return true if it's safe to let MethodHandles.convertArguments() to handle this conversion. |
| */ |
| /*private*/ static boolean canAutoConvert(final Class<?> fromType, final Class<?> toType) { |
| return TypeUtilities.isMethodInvocationConvertible(fromType, toType); |
| } |
| |
| /*private*/ MethodHandle getCacheableTypeConverterNull(final Class<?> sourceType, final Class<?> targetType) { |
| final MethodHandle converter = getCacheableTypeConverter(sourceType, targetType); |
| return converter == IDENTITY_CONVERSION ? null : converter; |
| } |
| |
| /*private*/ MethodHandle getTypeConverterNull(final Class<?> sourceType, final Class<?> targetType) { |
| try { |
| return getCacheableTypeConverterNull(sourceType, targetType); |
| } catch(final NotCacheableConverter e) { |
| return e.converter; |
| } |
| } |
| |
| /*private*/ MethodHandle getCacheableTypeConverter(final Class<?> sourceType, final Class<?> targetType) { |
| return converterMap.get(sourceType).get(targetType); |
| } |
| |
| /** |
| * 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 can use 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. |
| */ |
| MethodHandle getTypeConverter(final Class<?> sourceType, final Class<?> targetType) { |
| try { |
| return converterIdentityMap.get(sourceType).get(targetType); |
| } catch(final NotCacheableConverter e) { |
| return e.converter; |
| } |
| } |
| |
| private static class LookupSupplier implements Supplier<MethodHandles.Lookup> { |
| volatile boolean returnedLookup; |
| volatile boolean closed; |
| |
| @Override |
| public Lookup get() { |
| if (closed) { |
| // Something held on to this supplier and tried to invoke it |
| // after we're done with it. |
| throw new IllegalStateException(); |
| } |
| final Lookup lookup = LinkerServicesImpl.getCurrentLookup(); |
| returnedLookup = true; |
| return lookup; |
| } |
| } |
| |
| /*private*/ MethodHandle createConverter(final Class<?> sourceType, final Class<?> targetType) throws Exception { |
| final MethodType type = MethodType.methodType(targetType, sourceType); |
| final MethodHandle identity = IDENTITY_CONVERSION.asType(type); |
| MethodHandle last = identity; |
| |
| final LookupSupplier lookupSupplier = new LookupSupplier(); |
| try { |
| for(int i = factories.length; i-- > 0;) { |
| final GuardedInvocation next = factories[i].convertToType(sourceType, targetType, lookupSupplier); |
| if(next != null) { |
| last = next.compose(last); |
| } |
| } |
| } finally { |
| lookupSupplier.closed = true; |
| } |
| |
| if(last == identity) { |
| return IDENTITY_CONVERSION; |
| } |
| if(!lookupSupplier.returnedLookup) { |
| return last; |
| } |
| // At least one of the consulted converter factories obtained the |
| // lookup, so we must presume the created converter is sensitive to the |
| // lookup class and thus we will not cache it. |
| throw new NotCacheableConverter(last); |
| } |
| |
| /*private*/ static final MethodHandle IDENTITY_CONVERSION = MethodHandles.identity(Object.class); |
| |
| @SuppressWarnings("serial") |
| private static class NotCacheableConverter extends RuntimeException { |
| final MethodHandle converter; |
| |
| NotCacheableConverter(final MethodHandle converter) { |
| super("", null, false, false); |
| this.converter = converter; |
| } |
| } |
| } |