Mercurial > jdk8-mips64-public > nashorn / file revision

 /*

  * 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 java.lang.invoke.MethodHandle;

 import java.lang.invoke.MethodHandles;

 import java.lang.invoke.MethodType;

 import jdk.internal.dynalink.beans.BeansLinker;

 import jdk.internal.dynalink.linker.ConversionComparator.Comparison;

 import jdk.internal.dynalink.linker.GuardedInvocation;

 import jdk.internal.dynalink.linker.GuardingDynamicLinker;

 import jdk.internal.dynalink.linker.LinkRequest;

 import jdk.internal.dynalink.linker.LinkerServices;

 import jdk.internal.dynalink.support.Lookup;

 import jdk.nashorn.api.scripting.ScriptUtils;

 import jdk.nashorn.internal.objects.NativeArray;

 import jdk.nashorn.internal.runtime.ConsString;

 import jdk.nashorn.internal.runtime.ScriptObject;

 import jdk.nashorn.internal.runtime.options.Options;

 /**

  * This linker delegates to a {@code BeansLinker} but passes it a special linker services object that has a modified

  * {@code asType} method that will ensure that we never pass internal engine objects that should not be externally

  * observable (currently ConsString and ScriptObject) to Java APIs, but rather that we flatten it into a String. We can't just add

  * this functionality as custom converters via {@code GuaardingTypeConverterFactory}, since they are not consulted when

  * the target method handle parameter signature is {@code Object}.

  */

 public class NashornBeansLinker implements GuardingDynamicLinker {

     // System property to control whether to wrap ScriptObject->ScriptObjectMirror for

     // Object type arguments of Java method calls, field set and array set.

     private static final boolean MIRROR_ALWAYS = Options.getBooleanProperty("nashorn.mirror.always", true);

     private static final MethodHandle EXPORT_ARGUMENT = new Lookup(MethodHandles.lookup()).findOwnStatic("exportArgument", Object.class, Object.class);

     private static final MethodHandle EXPORT_NATIVE_ARRAY = new Lookup(MethodHandles.lookup()).findOwnStatic("exportNativeArray", Object.class, NativeArray.class);

     private static final MethodHandle EXPORT_SCRIPT_OBJECT = new Lookup(MethodHandles.lookup()).findOwnStatic("exportScriptObject", Object.class, ScriptObject.class);

     private static final MethodHandle IMPORT_RESULT = new Lookup(MethodHandles.lookup()).findOwnStatic("importResult", Object.class, Object.class);

     private final BeansLinker beansLinker = new BeansLinker();

     @Override

     public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {

         return getGuardedInvocation(beansLinker, linkRequest, linkerServices);

     }

     /**

      * Delegates to the specified linker but injects its linker services wrapper so that it will apply all special

      * conversions that this class does.

      * @param delegateLinker the linker to which the actual work is delegated to.

      * @param linkRequest the delegated link request

      * @param linkerServices the original link services that will be augmented with special conversions

      * @return the guarded invocation from the delegate, possibly augmented with special conversions

      * @throws Exception if the delegate throws an exception

      */

     public static GuardedInvocation getGuardedInvocation(final GuardingDynamicLinker delegateLinker, final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {

         return delegateLinker.getGuardedInvocation(linkRequest, new NashornBeansLinkerServices(linkerServices));

     }

     @SuppressWarnings("unused")

     private static Object exportArgument(final Object arg) {

         return exportArgument(arg, MIRROR_ALWAYS);

     }

     @SuppressWarnings("unused")

     private static Object exportNativeArray(final NativeArray arg) {

         return exportArgument(arg, MIRROR_ALWAYS);

     }

     @SuppressWarnings("unused")

     private static Object exportScriptObject(final ScriptObject arg) {

         return exportArgument(arg, MIRROR_ALWAYS);

     }

     @SuppressWarnings("unused")

     private static Object exportScriptArray(final NativeArray arg) {

         return exportArgument(arg, MIRROR_ALWAYS);

     }

     static Object exportArgument(final Object arg, final boolean mirrorAlways) {

         if (arg instanceof ConsString) {

             return arg.toString();

         } else if (mirrorAlways && arg instanceof ScriptObject) {

             return ScriptUtils.wrap((ScriptObject)arg);

         } else {

             return arg;

         }

     }

     @SuppressWarnings("unused")

     private static Object importResult(final Object arg) {

         return ScriptUtils.unwrap(arg);

     }

     private static class NashornBeansLinkerServices implements LinkerServices {

         private final LinkerServices linkerServices;

         NashornBeansLinkerServices(final LinkerServices linkerServices) {

             this.linkerServices = linkerServices;

         }

         @Override

         public MethodHandle asType(final MethodHandle handle, final MethodType fromType) {

             final MethodType handleType = handle.type();

             final int paramCount = handleType.parameterCount();

             assert fromType.parameterCount() == handleType.parameterCount();

             MethodType newFromType = fromType;

             MethodHandle[] filters = null;

             for(int i = 0; i < paramCount; ++i) {

                 final MethodHandle filter = argConversionFilter(handleType.parameterType(i), fromType.parameterType(i));

                 if (filter != null) {

                     if (filters == null) {

                         filters = new MethodHandle[paramCount];

                     }

                     // "erase" specific type with Object type or else we'll get filter mismatch

                     newFromType = newFromType.changeParameterType(i, Object.class);

                     filters[i] = filter;

                 }

             }

             final MethodHandle typed = linkerServices.asType(handle, newFromType);

             MethodHandle result = filters != null ? MethodHandles.filterArguments(typed, 0, filters) : typed;

             // Filter Object typed return value for possible ScriptObjectMirror. We convert

             // ScriptObjectMirror as ScriptObject (if it is mirror from current global).

             if (MIRROR_ALWAYS && areBothObjects(handleType.returnType(), fromType.returnType())) {

                 result = MethodHandles.filterReturnValue(result, IMPORT_RESULT);

             }

             return result;

         }

         private static MethodHandle argConversionFilter(final Class<?> handleType, final Class<?> fromType) {

             if (handleType == Object.class) {

                 if (fromType == Object.class) {

                     return EXPORT_ARGUMENT;

                 } else if (fromType == NativeArray.class) {

                     return EXPORT_NATIVE_ARRAY;

                 } else if (fromType == ScriptObject.class) {

                     return EXPORT_SCRIPT_OBJECT;

                 }

             }

             return null;

         }

         private static boolean areBothObjects(final Class<?> handleType, final Class<?> fromType) {

             return handleType == Object.class && fromType == Object.class;

         }

         @Override

         public MethodHandle asTypeLosslessReturn(final MethodHandle handle, final MethodType fromType) {

             return Implementation.asTypeLosslessReturn(this, handle, fromType);

         }

         @Override

         public MethodHandle getTypeConverter(final Class<?> sourceType, final Class<?> targetType) {

             return linkerServices.getTypeConverter(sourceType, targetType);

         }

         @Override

         public boolean canConvert(final Class<?> from, final Class<?> to) {

             return linkerServices.canConvert(from, to);

         }

         @Override

         public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest) throws Exception {

             return linkerServices.getGuardedInvocation(linkRequest);

         }

         @Override

         public Comparison compareConversion(final Class<?> sourceType, final Class<?> targetType1, final Class<?> targetType2) {

             if (sourceType == ConsString.class) {

                 if (String.class == targetType1 || CharSequence.class == targetType1) {

                     return Comparison.TYPE_1_BETTER;

                 }

                 if (String.class == targetType2 || CharSequence.class == targetType2) {

                     return Comparison.TYPE_2_BETTER;

                 }

             }

             return linkerServices.compareConversion(sourceType, targetType1, targetType2);

         }

     }

 }