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

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  */

 package jdk.nashorn.internal.runtime;

 import static jdk.nashorn.internal.runtime.ECMAErrors.referenceError;

 import static jdk.nashorn.internal.runtime.linker.Lookup.MH;

 import java.lang.invoke.MethodHandle;

 import jdk.nashorn.internal.codegen.objects.ObjectClassGenerator;

 import jdk.nashorn.internal.runtime.linker.Lookup;

 import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor;

 import jdk.nashorn.internal.runtime.linker.NashornGuards;

 import org.dynalang.dynalink.CallSiteDescriptor;

 import org.dynalang.dynalink.linker.GuardedInvocation;

 /**

  * Instances of this class are quite ephemeral; they only exist for the duration of an invocation of

  * {@link ScriptObject#findSetMethod(CallSiteDescriptor, org.dynalang.dynalink.linker.LinkRequest)} and

  * serve as the actual encapsulation of the algorithm for creating an appropriate property setter method.

  */

 final class SetMethodCreator {

     // See constructor parameters for description of fields

     private final ScriptObject sobj;

     private final PropertyMap map;

     private final FindProperty find;

     private final CallSiteDescriptor desc;

     /**

      * Creates a new property setter method creator.

      * @param sobj the object for which we're creating the property setter

      * @param find a result of a {@link ScriptObject#findProperty(String, boolean)} on the object for the property we

      * want to create a setter for. Can be null if the property does not yet exist on the object.

      * @param desc the descriptor of the call site that triggered the property setter lookup

      */

     SetMethodCreator(final ScriptObject sobj, final FindProperty find, final CallSiteDescriptor desc) {

         this.sobj = sobj;

         this.map = sobj.getMap();

         this.find = find;

         this.desc = desc;

     }

     private String getName() {

         return desc.getNameToken(CallSiteDescriptor.NAME_OPERAND);

     }

     private PropertyMap getMap() {

         return map;

     }

     /**

      * Creates the actual guarded invocation that represents the dynamic setter method for the property.

      * @return the actual guarded invocation that represents the dynamic setter method for the property.

      */

     GuardedInvocation createGuardedInvocation() {

         return createSetMethod().createGuardedInvocation();

     }

     /**

      * This class encapsulates the results of looking up a setter method; it's basically a triple of a method hanle,

      * a Property object, and flags for invocation.

      *

      */

     private class SetMethod {

         private final MethodHandle methodHandle;

         private final Property property;

         /**

          * Creates a new lookup result.

          * @param methodHandle the actual method handle

          * @param property the property object. Can be null in case we're creating a new property in the global object.

          */

         SetMethod(final MethodHandle methodHandle, final Property property) {

             assert methodHandle != null;

             this.methodHandle = methodHandle;

             this.property = property;

         }

         /**

          * Composes from its components an actual guarded invocation that represents the dynamic setter method for the property.

          * @return the composed guarded invocation that represents the dynamic setter method for the property.

          */

         GuardedInvocation createGuardedInvocation() {

             return new GuardedInvocation(methodHandle, getGuard());

         }

         private MethodHandle getGuard() {

             return needsNoGuard() ? null : NashornGuards.getMapGuard(getMap());

         }

         private boolean needsNoGuard() {

             return NashornCallSiteDescriptor.isFastScope(desc) &&

                     (ObjectClassGenerator.OBJECT_FIELDS_ONLY || isPropertyTypeStable());

         }

         private boolean isPropertyTypeStable() {

             return property == null || !property.canChangeType();

         }

     }

     private SetMethod createSetMethod() {

         if (find != null) {

             return createExistingPropertySetter();

         }

         checkStrictCreateNewVariable();

         if (sobj.isScope()) {

             return createGlobalPropertySetter();

         }

         return createNewPropertySetter();

     }

     private void checkStrictCreateNewVariable() {

         // In strict mode, assignment can not create a new variable.

         // See also ECMA Annex C item 4. ReferenceError is thrown.

         if (NashornCallSiteDescriptor.isScope(desc) && NashornCallSiteDescriptor.isStrict(desc)) {

             referenceError("not.defined", getName());

         }

     }

     private SetMethod createExistingPropertySetter() {

         final Property property = find.getProperty();

         final Class<?> type = desc.getMethodType().parameterType(1);

         final MethodHandle methodHandle = find.getSetter(type, NashornCallSiteDescriptor.isStrict(desc));

         assert methodHandle != null;

         assert property     != null;

         final MethodHandle boundHandle;

         if (!property.hasSetterFunction() && find.isInherited()) {

             boundHandle = ScriptObject.bindTo(methodHandle, find.getOwner());

         } else {

             boundHandle = methodHandle;

         }

         return new SetMethod(boundHandle, property);

     }

     private SetMethod createGlobalPropertySetter() {

         final ScriptObject global = Context.getGlobalTrusted();

         return new SetMethod(ScriptObject.bindTo(global.addSpill(getName()), global), null);

     }

     private SetMethod createNewPropertySetter() {

         final int nextEmbed = sobj.findEmbed();

         final SetMethod sm;

         if (nextEmbed >= ScriptObject.EMBED_SIZE) {

             sm = createNewSpillPropertySetter();

         } else {

             sm = createNewEmbedPropertySetter(nextEmbed);

         }

         sobj.notifyPropertyAdded(sobj, sm.property);

         return sm;

     }

     private SetMethod createNewSpillPropertySetter() {

         final int nextSpill = getMap().getSpillLength();

         final Property property = createSpillProperty(nextSpill);

         return new SetMethod(createSpillMethodHandle(nextSpill, property), property);

     }

     private Property createSpillProperty(final int nextSpill) {

         final MethodHandle getter = MH.asType(MH.insertArguments(MH.arrayElementGetter(Object[].class), 1, nextSpill), Lookup.GET_OBJECT_TYPE);

         final MethodHandle setter = MH.asType(MH.insertArguments(MH.arrayElementSetter(Object[].class), 1, nextSpill), Lookup.SET_OBJECT_TYPE);

         return new SpillProperty(getName(), Property.IS_SPILL, nextSpill, getter, setter);

     }

     private MethodHandle createSpillMethodHandle(final int nextSpill, Property property) {

         final PropertyMap oldMap = getMap();

         final PropertyMap newMap = getNewMap(property);

         final Object[] spill = sobj.spill;

         if (spill == null) {

             return MH.insertArguments(ScriptObject.SETSPILLWITHNEW,  0, desc, oldMap, newMap, nextSpill);

         } else if (nextSpill < spill.length) {

             return MH.insertArguments(ScriptObject.SETSPILL,         0, desc, oldMap, newMap, nextSpill);

         } else {

             final int newLength = (nextSpill + ScriptObject.SPILL_RATE) / ScriptObject.SPILL_RATE * ScriptObject.SPILL_RATE;

             return MH.insertArguments(ScriptObject.SETSPILLWITHGROW, 0, desc, oldMap, newMap, nextSpill, newLength);

         }

     }

     private SetMethod createNewEmbedPropertySetter(final int nextEmbed) {

         sobj.useEmbed(nextEmbed);

         final Property property = new SpillProperty(getName(), 0, nextEmbed, ScriptObject.GET_EMBED[nextEmbed], ScriptObject.SET_EMBED[nextEmbed]);

         //TODO specfields

         final MethodHandle methodHandle = MH.insertArguments(ScriptObject.SETEMBED, 0, desc, getMap(), getNewMap(property), property.getSetter(Object.class, getMap()), nextEmbed);

         return new SetMethod(methodHandle, property);

     }

     private PropertyMap getNewMap(Property property) {

         return getMap().addProperty(property);

     }

 }