| /* |
| * 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. |
| */ |
| |
| package jdk.nashorn.internal.runtime.linker; |
| |
| import static jdk.nashorn.internal.lookup.Lookup.MH; |
| |
| import java.lang.invoke.MethodHandle; |
| import java.lang.invoke.MethodHandles; |
| import jdk.internal.dynalink.CallSiteDescriptor; |
| import jdk.internal.dynalink.linker.ConversionComparator; |
| import jdk.internal.dynalink.linker.GuardedInvocation; |
| import jdk.internal.dynalink.linker.GuardingTypeConverterFactory; |
| import jdk.internal.dynalink.linker.LinkRequest; |
| import jdk.internal.dynalink.linker.LinkerServices; |
| import jdk.internal.dynalink.linker.TypeBasedGuardingDynamicLinker; |
| import jdk.internal.dynalink.support.Guards; |
| import jdk.nashorn.internal.runtime.ScriptFunction; |
| import jdk.nashorn.internal.runtime.ScriptObject; |
| import jdk.nashorn.internal.runtime.Undefined; |
| |
| /** |
| * This is the main dynamic linker for Nashorn. It is used for linking all {@link ScriptObject} and its subclasses (this |
| * includes {@link ScriptFunction} and its subclasses) as well as {@link Undefined}. This linker is exported to other |
| * language runtimes by being declared in {@code META-INF/services/jdk.internal.dynalink.linker.GuardingDynamicLinker} |
| * file of Nashorn's distribution. |
| */ |
| final class NashornLinker implements TypeBasedGuardingDynamicLinker, GuardingTypeConverterFactory, ConversionComparator { |
| /** |
| * Returns true if {@code ScriptObject} is assignable from {@code type}, or it is {@code Undefined}. |
| */ |
| @Override |
| public boolean canLinkType(final Class<?> type) { |
| return canLinkTypeStatic(type); |
| } |
| |
| static boolean canLinkTypeStatic(final Class<?> type) { |
| return ScriptObject.class.isAssignableFrom(type) || Undefined.class == type; |
| } |
| |
| @Override |
| public GuardedInvocation getGuardedInvocation(final LinkRequest request, final LinkerServices linkerServices) throws Exception { |
| final LinkRequest requestWithoutContext = request.withoutRuntimeContext(); // Nashorn has no runtime context |
| final Object self = requestWithoutContext.getReceiver(); |
| final CallSiteDescriptor desc = requestWithoutContext.getCallSiteDescriptor(); |
| |
| if (desc.getNameTokenCount() < 2 || !"dyn".equals(desc.getNameToken(CallSiteDescriptor.SCHEME))) { |
| // We only support standard "dyn:*[:*]" operations |
| return null; |
| } |
| |
| final GuardedInvocation inv; |
| if (self instanceof ScriptObject) { |
| inv = ((ScriptObject)self).lookup(desc, request); |
| } else if (self instanceof Undefined) { |
| inv = Undefined.lookup(desc); |
| } else { |
| throw new AssertionError(); // Should never reach here. |
| } |
| |
| return Bootstrap.asType(inv, linkerServices, desc); |
| } |
| |
| @Override |
| public GuardedInvocation convertToType(final Class<?> sourceType, final Class<?> targetType) throws Exception { |
| final GuardedInvocation gi = convertToTypeNoCast(sourceType, targetType); |
| return gi == null ? null : gi.asType(MH.type(targetType, sourceType)); |
| } |
| |
| /** |
| * Main part of the implementation of {@link GuardingTypeConverterFactory#convertToType(Class, Class)} that doesn't |
| * care about adapting the method signature; that's done by the invoking method. Returns either a built-in |
| * conversion to primitive (or primitive wrapper) Java types or to String, or a just-in-time generated converter to |
| * a SAM type (if the target type is a SAM type). |
| * @param sourceType the source type |
| * @param targetType the target type |
| * @return a guarded invocation that converts from the source type to the target type. |
| * @throws Exception if something goes wrong |
| */ |
| private static GuardedInvocation convertToTypeNoCast(final Class<?> sourceType, final Class<?> targetType) throws Exception { |
| final MethodHandle mh = JavaArgumentConverters.getConverter(targetType); |
| if (mh != null) { |
| return new GuardedInvocation(mh, canLinkTypeStatic(sourceType) ? null : IS_NASHORN_OR_UNDEFINED_TYPE); |
| } |
| return getSamTypeConverter(sourceType, targetType); |
| } |
| |
| /** |
| * Returns a guarded invocation that converts from a source type that is ScriptFunction, or a subclass or a |
| * superclass of it) to a SAM type. |
| * @param sourceType the source type (presumably ScriptFunction or a subclass or a superclass of it) |
| * @param targetType the target type (presumably a SAM type) |
| * @return a guarded invocation that converts from the source type to the target SAM type. null is returned if |
| * either the source type is neither ScriptFunction, nor a subclass, nor a superclass of it, or if the target type |
| * is not a SAM type. |
| * @throws Exception if something goes wrong; generally, if there's an issue with creation of the SAM proxy type |
| * constructor. |
| */ |
| private static GuardedInvocation getSamTypeConverter(final Class<?> sourceType, final Class<?> targetType) throws Exception { |
| // If source type is more generic than ScriptFunction class, we'll need to use a guard |
| final boolean isSourceTypeGeneric = sourceType.isAssignableFrom(ScriptFunction.class); |
| |
| if ((isSourceTypeGeneric || ScriptFunction.class.isAssignableFrom(sourceType)) && isAutoConvertibleFromFunction(targetType)) { |
| final MethodHandle ctor = JavaAdapterFactory.getConstructor(ScriptFunction.class, targetType); |
| assert ctor != null; // if isAutoConvertibleFromFunction() returned true, then ctor must exist. |
| return new GuardedInvocation(ctor, isSourceTypeGeneric ? IS_SCRIPT_FUNCTION : null); |
| } |
| return null; |
| } |
| |
| private static boolean isAutoConvertibleFromFunction(final Class<?> clazz) { |
| return JavaAdapterFactory.isAbstractClass(clazz) && !ScriptObject.class.isAssignableFrom(clazz) && |
| JavaAdapterFactory.isAutoConvertibleFromFunction(clazz); |
| } |
| |
| @Override |
| public Comparison compareConversion(final Class<?> sourceType, final Class<?> targetType1, final Class<?> targetType2) { |
| if(ScriptObject.class.isAssignableFrom(sourceType)) { |
| if(targetType1.isInterface()) { |
| if(!targetType2.isInterface()) { |
| return Comparison.TYPE_1_BETTER; |
| } |
| } else if(targetType2.isInterface()) { |
| return Comparison.TYPE_2_BETTER; |
| } |
| } |
| return Comparison.INDETERMINATE; |
| } |
| |
| private static final MethodHandle IS_SCRIPT_FUNCTION = Guards.isInstance(ScriptFunction.class, MH.type(Boolean.TYPE, Object.class)); |
| |
| private static final MethodHandle IS_NASHORN_OR_UNDEFINED_TYPE = findOwnMH("isNashornTypeOrUndefined", |
| Boolean.TYPE, Object.class); |
| |
| @SuppressWarnings("unused") |
| private static boolean isNashornTypeOrUndefined(final Object obj) { |
| return obj instanceof ScriptObject || obj instanceof Undefined; |
| } |
| |
| private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { |
| return MH.findStatic(MethodHandles.lookup(), NashornLinker.class, name, MH.type(rtype, types)); |
| } |
| } |
| |