1 /*
   2  * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.nashorn.internal.runtime.linker;
  27 
  28 import static jdk.nashorn.internal.lookup.Lookup.MH;


  29 import java.lang.invoke.MethodHandle;

  30 import java.lang.invoke.MethodType;
  31 import java.lang.invoke.SwitchPoint;
  32 import jdk.internal.dynalink.CallSiteDescriptor;
  33 import jdk.internal.dynalink.linker.GuardedInvocation;
  34 import jdk.internal.dynalink.linker.LinkRequest;

  35 import jdk.internal.dynalink.support.Guards;
  36 import jdk.nashorn.internal.runtime.Context;
  37 import jdk.nashorn.internal.runtime.FindProperty;
  38 import jdk.nashorn.internal.runtime.GlobalConstants;

  39 import jdk.nashorn.internal.runtime.ScriptObject;

  40 import jdk.nashorn.internal.runtime.UserAccessorProperty;
  41 
  42 /**
  43  * Implements lookup of methods to link for dynamic operations on JavaScript primitive values (booleans, strings, and
  44  * numbers). This class is only public so it can be accessed by classes in the {@code jdk.nashorn.internal.objects}
  45  * package.
  46  */
  47 public final class PrimitiveLookup {
  48 





  49     private PrimitiveLookup() {
  50     }
  51 
  52     /**
  53      * Returns a guarded invocation representing the linkage for a dynamic operation on a primitive Java value.
  54      * @param request the link request for the dynamic call site.
  55      * @param receiverClass the class of the receiver value (e.g., {@link java.lang.Boolean}, {@link java.lang.String} etc.)
  56      * @param wrappedReceiver a transient JavaScript native wrapper object created as the object proxy for the primitive
  57      * value; see ECMAScript 5.1, section 8.7.1 for discussion of using {@code [[Get]]} on a property reference with a
  58      * primitive base value. This instance will be used to delegate actual lookup.
  59      * @param wrapFilter A method handle that takes a primitive value of type specified in the {@code receiverClass} and
  60      * creates a transient native wrapper of the same type as {@code wrappedReceiver} for subsequent invocations of the
  61      * method - it will be combined into the returned invocation as an argument filter on the receiver.
  62      * @return a guarded invocation representing the operation at the call site when performed on a JavaScript primitive
  63      * @param protoFilter A method handle that walks up the proto chain of this receiver object
  64      * type {@code receiverClass}.
  65      */
  66     public static GuardedInvocation lookupPrimitive(final LinkRequest request, final Class<?> receiverClass,
  67                                                     final ScriptObject wrappedReceiver, final MethodHandle wrapFilter,
  68                                                     final MethodHandle protoFilter) {
  69         return lookupPrimitive(request, Guards.getInstanceOfGuard(receiverClass), wrappedReceiver, wrapFilter, protoFilter);
  70     }
  71 
  72     /**
  73      * Returns a guarded invocation representing the linkage for a dynamic operation on a primitive Java value.
  74      * @param request the link request for the dynamic call site.
  75      * @param guard an explicit guard that will be used for the returned guarded invocation.
  76      * @param wrappedReceiver a transient JavaScript native wrapper object created as the object proxy for the primitive
  77      * value; see ECMAScript 5.1, section 8.7.1 for discussion of using {@code [[Get]]} on a property reference with a
  78      * primitive base value. This instance will be used to delegate actual lookup.
  79      * @param wrapFilter A method handle that takes a primitive value of type guarded by the {@code guard} and
  80      * creates a transient native wrapper of the same type as {@code wrappedReceiver} for subsequent invocations of the
  81      * method - it will be combined into the returned invocation as an argument filter on the receiver.
  82      * @param protoFilter A method handle that walks up the proto chain of this receiver object
  83      * @return a guarded invocation representing the operation at the call site when performed on a JavaScript primitive
  84      * type (that is implied by both {@code guard} and {@code wrappedReceiver}).
  85      */
  86     public static GuardedInvocation lookupPrimitive(final LinkRequest request, final MethodHandle guard,
  87                                                     final ScriptObject wrappedReceiver, final MethodHandle wrapFilter,
  88                                                     final MethodHandle protoFilter) {
  89         final CallSiteDescriptor desc = request.getCallSiteDescriptor();










  90 






  91         //checks whether the property name is hard-coded in the call-site (i.e. a getProp vs a getElem, or setProp vs setElem)
  92         //if it is we can make assumptions on the property: that if it is not defined on primitive wrapper itself it never will be.
  93         //so in that case we can skip creation of primitive wrapper and start our search with the prototype.
  94         if (desc.getNameTokenCount() > 2) {
  95             final String name = desc.getNameToken(CallSiteDescriptor.NAME_OPERAND);
  96             final FindProperty find = wrappedReceiver.findProperty(name, true);
  97 
  98             if (find == null) {
  99                 // Give up early, give chance to BeanLinker and NashornBottomLinker to deal with it.
 100                 return null;
 101             }
 102 
 103             final SwitchPoint sp = find.getProperty().getBuiltinSwitchPoint(); //can use this instead of proto filter
 104             if (sp instanceof Context.BuiltinSwitchPoint && !sp.hasBeenInvalidated()) {
 105                 return new GuardedInvocation(GlobalConstants.staticConstantGetter(find.getObjectValue()), guard, sp, null);
 106             }
 107 
 108             if (find.isInherited() && !(find.getProperty() instanceof UserAccessorProperty)) {
 109                 // If property is found in the prototype object bind the method handle directly to
 110                 // the proto filter instead of going through wrapper instantiation below.
 111                 final ScriptObject proto = wrappedReceiver.getProto();
 112                 final GuardedInvocation link = proto.lookup(desc, request);
 113 
 114                 if (link != null) {
 115                     final MethodHandle invocation = link.getInvocation(); //this contains the builtin switchpoint
 116 
 117                     final MethodHandle adaptedInvocation = MH.asType(invocation, invocation.type().changeParameterType(0, Object.class));
 118                     final MethodHandle method = MH.filterArguments(adaptedInvocation, 0, protoFilter);
 119                     final MethodHandle protoGuard = MH.filterArguments(link.getGuard(), 0, protoFilter);
 120 
 121                     return new GuardedInvocation(method, NashornGuards.combineGuards(guard, protoGuard));
 122                 }
 123             }
 124         }







 125 
 126         final GuardedInvocation link = wrappedReceiver.lookup(desc, request);
 127         if (link != null) {
 128             MethodHandle method = link.getInvocation();
 129             final Class<?> receiverType = method.type().parameterType(0);
 130             if (receiverType != Object.class) {
 131                 final MethodType wrapType = wrapFilter.type();
 132                 assert receiverType.isAssignableFrom(wrapType.returnType());
 133                 method = MH.filterArguments(method, 0, MH.asType(wrapFilter, wrapType.changeReturnType(receiverType)));
 134             }
 135 
 136             return new GuardedInvocation(method, guard, link.getSwitchPoints(), null);
 137         }
 138 
 139         return null;





































 140     }
 141 }
--- EOF ---