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.objects;

 import static jdk.nashorn.internal.lookup.Lookup.MH;

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

 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;

 import java.lang.invoke.MethodHandle;

 import java.lang.invoke.MethodHandles;

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.BitSet;

 import jdk.nashorn.internal.runtime.AccessorProperty;

 import jdk.nashorn.internal.runtime.Property;

 import jdk.nashorn.internal.runtime.PropertyDescriptor;

 import jdk.nashorn.internal.runtime.PropertyMap;

 import jdk.nashorn.internal.runtime.ScriptFunction;

 import jdk.nashorn.internal.runtime.ScriptObject;

 import jdk.nashorn.internal.runtime.ScriptRuntime;

 import jdk.nashorn.internal.runtime.arrays.ArrayData;

 import jdk.nashorn.internal.runtime.arrays.ArrayIndex;

 /**

  * ECMA 10.6 Arguments Object.

  *

  * Arguments object used for non-strict mode functions. For strict mode, we use

  * a different implementation (@see NativeStrictArguments). In non-strict mode,

  * named argument access and index argument access (arguments[i]) are linked.

  * Modifications reflect on each other access -- till arguments indexed element

  * is deleted. After delete, there is no link between named access and indexed

  * access for that deleted index alone.

  */

 public final class NativeArguments extends ScriptObject {

     private static final MethodHandle G$LENGTH = findOwnMH("G$length", Object.class, Object.class);

     private static final MethodHandle S$LENGTH = findOwnMH("S$length", void.class, Object.class, Object.class);

     private static final MethodHandle G$CALLEE = findOwnMH("G$callee", Object.class, Object.class);

     private static final MethodHandle S$CALLEE = findOwnMH("S$callee", void.class, Object.class, Object.class);

     private static final PropertyMap map$;

     static {

         final ArrayList<Property> properties = new ArrayList<>(2);

         properties.add(AccessorProperty.create("length", Property.NOT_ENUMERABLE, G$LENGTH, S$LENGTH));

         properties.add(AccessorProperty.create("callee", Property.NOT_ENUMERABLE, G$CALLEE, S$CALLEE));

         map$ = PropertyMap.newMap(properties).setIsShared();

     }

     static PropertyMap getInitialMap() {

         return map$;

     }

     private Object length;

     private Object callee;

     private final int numMapped;

     private final int numParams;

     // These are lazily initialized when delete is invoked on a mapped arg or an unmapped argument is set.

     private ArrayData unmappedArgs;

     private BitSet deleted;

     NativeArguments(final Object[] arguments, final Object callee, final int numParams, final ScriptObject proto, final PropertyMap map) {

         super(proto, map);

         setIsArguments();

         setArray(ArrayData.allocate(arguments));

         this.length = arguments.length;

         this.callee = callee;

         this.numMapped = Math.min(numParams, arguments.length);

         this.numParams = numParams;

     }

     @Override

     public String getClassName() {

         return "Arguments";

     }

     /**

      * getArgument is used for named argument access.

      */

     @Override

     public Object getArgument(final int key) {

         assert key >= 0 && key < numParams : "invalid argument index";

         return isMapped(key) ? getArray().getObject(key) : getUnmappedArg(key);

     }

     /**

      * setArgument is used for named argument set.

      */

     @Override

     public void setArgument(final int key, final Object value) {

         assert key >= 0 && key < numParams : "invalid argument index";

         if (isMapped(key)) {

             setArray(getArray().set(key, value, false));

         } else {

             setUnmappedArg(key, value);

         }

     }

     @Override

     public boolean delete(final int key, final boolean strict) {

         final int index = ArrayIndex.getArrayIndex(key);

         return isMapped(index) ? deleteMapped(index, strict) : super.delete(key, strict);

     }

     @Override

     public boolean delete(final long key, final boolean strict) {

         final int index = ArrayIndex.getArrayIndex(key);

         return isMapped(index) ? deleteMapped(index, strict) : super.delete(key, strict);

     }

     @Override

     public boolean delete(final double key, final boolean strict) {

         final int index = ArrayIndex.getArrayIndex(key);

         return isMapped(index) ? deleteMapped(index, strict) : super.delete(key, strict);

     }

     @Override

     public boolean delete(final Object key, final boolean strict) {

         final int index = ArrayIndex.getArrayIndex(key);

         return isMapped(index) ? deleteMapped(index, strict) : super.delete(key, strict);

     }

     /**

      * ECMA 15.4.5.1 [[DefineOwnProperty]] ( P, Desc, Throw ) as specialized in

      * ECMA 10.6 for Arguments object.

      */

     @Override

     public boolean defineOwnProperty(final String key, final Object propertyDesc, final boolean reject) {

         final int index = ArrayIndex.getArrayIndex(key);

         if (index >= 0) {

             final boolean isMapped = isMapped(index);

             final Object oldValue = isMapped ? getArray().getObject(index) : null;

             if (!super.defineOwnProperty(key, propertyDesc, false)) {

                 if (reject) {

                     throw typeError("cant.redefine.property",  key, ScriptRuntime.safeToString(this));

                 }

                 return false;

             }

             if (isMapped) {

                 // When mapped argument is redefined, if new descriptor is accessor property

                 // or data-non-writable property, we have to "unmap" (unlink).

                 final PropertyDescriptor desc = toPropertyDescriptor(Global.instance(), propertyDesc);

                 if (desc.type() == PropertyDescriptor.ACCESSOR) {

                     setDeleted(index, oldValue);

                 } else if (desc.has(PropertyDescriptor.WRITABLE) && !desc.isWritable()) {

                     // delete and set value from new descriptor if it has one, otherwise use old value

                     setDeleted(index, desc.has(PropertyDescriptor.VALUE) ? desc.getValue() : oldValue);

                 } else if (desc.has(PropertyDescriptor.VALUE)) {

                     setArray(getArray().set(index, desc.getValue(), false));

                 }

             }

             return true;

         }

         return super.defineOwnProperty(key, propertyDesc, reject);

     }

     // Internals below this point

     // We track deletions using a bit set (delete arguments[index])

     private boolean isDeleted(final int index) {

         return deleted != null && deleted.get(index);

     }

     private void setDeleted(final int index, final Object unmappedValue) {

         if (deleted == null) {

             deleted = new BitSet(numMapped);

         }

         deleted.set(index, true);

         setUnmappedArg(index, unmappedValue);

     }

     private boolean deleteMapped(final int index, final boolean strict) {

         final Object value = getArray().getObject(index);

         final boolean success = super.delete(index, strict);

         if (success) {

             setDeleted(index, value);

         }

         return success;

     }

     private Object getUnmappedArg(final int key) {

         assert key >= 0 && key < numParams;

         return unmappedArgs == null ? UNDEFINED : unmappedArgs.getObject(key);

     }

     private void setUnmappedArg(final int key, final Object value) {

         assert key >= 0 && key < numParams;

         if (unmappedArgs == null) {

             /*

              * Declared number of parameters may be more or less than the actual passed

              * runtime arguments count. We need to truncate or extend with undefined values.

              *

              * Example:

              *

              * // less declared params

              * (function (x) { print(arguments); })(20, 44);

              *

              * // more declared params

              * (function (x, y) { print(arguments); })(3);

              */

             final Object[] newValues = new Object[numParams];

             System.arraycopy(getArray().asObjectArray(), 0, newValues, 0, numMapped);

             if (numMapped < numParams) {

                 Arrays.fill(newValues, numMapped, numParams, UNDEFINED);

             }

             this.unmappedArgs = ArrayData.allocate(newValues);

         }

         // Set value of argument

         unmappedArgs = unmappedArgs.set(key, value, false);

     }

     /**

      * Are arguments[index] and corresponding named parameter linked?

      *

      * In non-strict mode, arguments[index] and corresponding named param are "linked" or "mapped"

      * if the argument is provided by the caller. Modifications are tacked b/w each other - until

      * (delete arguments[index]) is used. Once deleted, the corresponding arg is no longer 'mapped'.

      * Please note that delete can happen only through the arguments array - named param can not

      * be deleted. (delete is one-way).

      */

     private boolean isMapped(final int index) {

         // in mapped named args and not marked as "deleted"

         return index >= 0 && index < numMapped && !isDeleted(index);

     }

     /**

      * Factory to create correct Arguments object based on strict mode.

      *

      * @param arguments the actual arguments array passed

      * @param callee the callee function that uses arguments object

      * @param numParams the number of declared (named) function parameters

      * @return Arguments Object

      */

     public static ScriptObject allocate(final Object[] arguments, final ScriptFunction callee, final int numParams) {

         // Strict functions won't always have a callee for arguments, and will pass null instead.

         final boolean isStrict = callee == null || callee.isStrict();

         final Global global = Global.instance();

         final ScriptObject proto = global.getObjectPrototype();

         if (isStrict) {

             return new NativeStrictArguments(arguments, numParams, proto, global.getStrictArgumentsMap());

         }

         return new NativeArguments(arguments, callee, numParams, proto, global.getArgumentsMap());

     }

     /**

      * Length getter

      * @param self self reference

      * @return length property value

      */

     public static Object G$length(final Object self) {

         if (self instanceof NativeArguments) {

             return ((NativeArguments)self).getArgumentsLength();

         }

         return 0;

     }

     /**

      * Length setter

      * @param self self reference

      * @param value value for length property

      */

     public static void S$length(final Object self, final Object value) {

         if (self instanceof NativeArguments) {

             ((NativeArguments)self).setArgumentsLength(value);

         }

     }

     /**

      * Callee getter

      * @param self self reference

      * @return value for callee property

      */

     public static Object G$callee(final Object self) {

         if (self instanceof NativeArguments) {

             return ((NativeArguments)self).getCallee();

         }

         return UNDEFINED;

     }

     /**

      * Callee setter

      * @param self self reference

      * @param value value for callee property

      */

     public static void S$callee(final Object self, final Object value) {

         if (self instanceof NativeArguments) {

             ((NativeArguments)self).setCallee(value);

         }

     }

     @Override

     public Object getLength() {

         return length;

     }

     private Object getArgumentsLength() {

         return length;

     }

     private void setArgumentsLength(final Object length) {

         this.length = length;

     }

     private Object getCallee() {

         return callee;

     }

     private void setCallee(final Object callee) {

         this.callee = callee;

     }

     private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {

         return MH.findStatic(MethodHandles.lookup(), NativeArguments.class, name, MH.type(rtype, types));

     }

 }