jdk8-mips64-public/nashorn: src/jdk/nashorn/internal/runtime/linker/NashornPrimitiveLinker.java@61ffdd1b89f2 (annotated)

src/jdk/nashorn/internal/runtime/linker/NashornPrimitiveLinker.java@61ffdd1b89f2 (annotated)

src/jdk/nashorn/internal/runtime/linker/NashornPrimitiveLinker.java

Thu, 24 May 2018 16:39:31 +0800

author: aoqi
date: Thu, 24 May 2018 16:39:31 +0800
changeset 1959: 61ffdd1b89f2
parent 1721: bfc671539e50
parent 1490: d85f981c8cf8
permissions: -rw-r--r--

Merge

 /*
  * 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.linker.ConversionComparator;
 import jdk.internal.dynalink.linker.GuardedInvocation;
 import jdk.internal.dynalink.linker.GuardedTypeConversion;
 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.TypeUtilities;
 import jdk.nashorn.internal.objects.Global;
 import jdk.nashorn.internal.runtime.ConsString;
 import jdk.nashorn.internal.runtime.JSType;
 import jdk.nashorn.internal.runtime.ScriptRuntime;
 /**
  * Internal linker for String, Boolean, and Number objects, only ever used by Nashorn engine and not exposed to other
  * engines. It is used for treatment of strings, boolean, and numbers as JavaScript primitives. Also provides ECMAScript
  * primitive type conversions for these types when linking to Java methods.
  */
 final class NashornPrimitiveLinker implements TypeBasedGuardingDynamicLinker, GuardingTypeConverterFactory, ConversionComparator {
     private static final GuardedTypeConversion VOID_TO_OBJECT = new GuardedTypeConversion(
             new GuardedInvocation(MethodHandles.constant(Object.class, ScriptRuntime.UNDEFINED)), true);
     @Override
     public boolean canLinkType(final Class<?> type) {
         return canLinkTypeStatic(type);
     }
     private static boolean canLinkTypeStatic(final Class<?> type) {
         return type == String.class || type == Boolean.class || type == ConsString.class || type == Integer.class
                 || type == Double.class || type == Float.class || type == Short.class || type == Byte.class;
     }
     @Override
     public GuardedInvocation getGuardedInvocation(final LinkRequest origRequest, final LinkerServices linkerServices)
             throws Exception {
         final LinkRequest request = origRequest.withoutRuntimeContext(); // Nashorn has no runtime context
         final Object self = request.getReceiver();
         final NashornCallSiteDescriptor desc = (NashornCallSiteDescriptor) request.getCallSiteDescriptor();
         return Bootstrap.asTypeSafeReturn(Global.primitiveLookup(request, self), linkerServices, desc);
     }
     /**
      * This implementation of type converter factory will pretty much allow implicit conversions of anything to anything
      * else that's allowed among JavaScript primitive types (string to number, boolean to string, etc.)
      * @param sourceType the type to convert from
      * @param targetType the type to convert to
      * @return a conditional converter from source to target type
      */
     @Override
     public GuardedTypeConversion convertToType(final Class<?> sourceType, final Class<?> targetType) {
         final MethodHandle mh = JavaArgumentConverters.getConverter(targetType);
         if (mh == null) {
             if(targetType == Object.class && sourceType == void.class) {
                 return VOID_TO_OBJECT;
             }
             return null;
         }
         return new GuardedTypeConversion(new GuardedInvocation(mh, canLinkTypeStatic(sourceType) ? null : GUARD_PRIMITIVE).asType(mh.type().changeParameterType(0, sourceType)), true);
     }
     /**
      * Implements the somewhat involved prioritization of JavaScript primitive types conversions. Instead of explaining
      * it here in prose, just follow the source code comments.
      * @param sourceType the source type to convert from
      * @param targetType1 one candidate target type
      * @param targetType2 another candidate target type
      * @return one of {@link jdk.internal.dynalink.linker.ConversionComparator.Comparison} values signifying which
      * target type should be favored for conversion.
      */
     @Override
     public Comparison compareConversion(final Class<?> sourceType, final Class<?> targetType1, final Class<?> targetType2) {
         final Class<?> wrapper1 = getWrapperTypeOrSelf(targetType1);
         if (sourceType == wrapper1) {
             // Source type exactly matches target 1
             return Comparison.TYPE_1_BETTER;
         }
         final Class<?> wrapper2 = getWrapperTypeOrSelf(targetType2);
         if (sourceType == wrapper2) {
             // Source type exactly matches target 2
             return Comparison.TYPE_2_BETTER;
         }
         if (Number.class.isAssignableFrom(sourceType)) {
             // If exactly one of the targets is a number, pick it.
             if (Number.class.isAssignableFrom(wrapper1)) {
                 if (!Number.class.isAssignableFrom(wrapper2)) {
                     return Comparison.TYPE_1_BETTER;
                 }
             } else if (Number.class.isAssignableFrom(wrapper2)) {
                 return Comparison.TYPE_2_BETTER;
             }
             // If exactly one of the targets is a character, pick it. Numbers can be reasonably converted to chars using
             // the UTF-16 values.
             if (Character.class == wrapper1) {
                 return Comparison.TYPE_1_BETTER;
             } else if (Character.class == wrapper2) {
                 return Comparison.TYPE_2_BETTER;
             }
             // For all other cases, we fall through to the next if statement - not that we repeat the condition in it
             // too so if we entered this branch, we'll enter the below if statement too.
         }
         if (sourceType == String.class || sourceType == Boolean.class || Number.class.isAssignableFrom(sourceType)) {
             // Treat wrappers as primitives.
             final Class<?> primitiveType1 = getPrimitiveTypeOrSelf(targetType1);
             final Class<?> primitiveType2 = getPrimitiveTypeOrSelf(targetType2);
             // Basically, choose the widest possible primitive type. (First "if" returning TYPE_2_BETTER is correct;
             // when faced with a choice between double and int, choose double).
             if (TypeUtilities.isMethodInvocationConvertible(primitiveType1, primitiveType2)) {
                 return Comparison.TYPE_2_BETTER;
             } else if (TypeUtilities.isMethodInvocationConvertible(primitiveType2, primitiveType1)) {
                 return Comparison.TYPE_1_BETTER;
             }
             // Ok, at this point we're out of possible number conversions, so try strings. A String can represent any
             // value without loss, so if one of the potential targets is string, go for it.
             if (targetType1 == String.class) {
                 return Comparison.TYPE_1_BETTER;
             }
             if (targetType2 == String.class) {
                 return Comparison.TYPE_2_BETTER;
             }
         }
         return Comparison.INDETERMINATE;
     }
     private static Class<?> getPrimitiveTypeOrSelf(final Class<?> type) {
         final Class<?> primitive = TypeUtilities.getPrimitiveType(type);
         return primitive == null ? type : primitive;
     }
     private static Class<?> getWrapperTypeOrSelf(final Class<?> type) {
         final Class<?> wrapper = TypeUtilities.getWrapperType(type);
         return wrapper == null ? type : wrapper;
     }
     @SuppressWarnings("unused")
     private static boolean isJavaScriptPrimitive(final Object o) {
         return JSType.isString(o) || o instanceof Boolean || JSType.isNumber(o) || o == null;
     }
     private static final MethodHandle GUARD_PRIMITIVE = findOwnMH("isJavaScriptPrimitive", boolean.class, Object.class);
     private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {
         return MH.findStatic(MethodHandles.lookup(), NashornPrimitiveLinker.class, name, MH.type(rtype, types));
     }
 }

Mercurial > jdk8-mips64-public > nashorn / annotate

src/jdk/nashorn/internal/runtime/linker/NashornPrimitiveLinker.java@61ffdd1b89f2 (annotated)

src/jdk/nashorn/internal/runtime/linker/NashornPrimitiveLinker.java