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 
  30 import java.lang.invoke.MethodHandle;
  31 import java.lang.invoke.MethodType;
  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.CallSiteDescriptorFactory;
  36 import jdk.internal.dynalink.support.Guards;
  37 import jdk.nashorn.internal.lookup.Lookup;
  38 import jdk.nashorn.internal.runtime.ScriptObject;
  39 
  40 /**
  41  * Implements lookup of methods to link for dynamic operations on JavaScript primitive values (booleans, strings, and
  42  * numbers). This class is only public so it can be accessed by classes in the {@code jdk.nashorn.internal.objects}
  43  * package.
  44  */
  45 public final class PrimitiveLookup {
  46 
  47     private PrimitiveLookup() {
  48     }
  49 
  50     /**
  51      * Returns a guarded invocation representing the linkage for a dynamic operation on a primitive Java value.
  52      * @param request the link request for the dynamic call site.
  53      * @param receiverClass the class of the receiver value (e.g., {@link java.lang.Boolean}, {@link java.lang.String} etc.)
  54      * @param wrappedReceiver a transient JavaScript native wrapper object created as the object proxy for the primitive
  55      * value; see ECMAScript 5.1, section 8.7.1 for discussion of using {@code [[Get]]} on a property reference with a
  56      * primitive base value. This instance will be used to delegate actual lookup.
  57      * @param wrapFilter A method handle that takes a primitive value of type specified in the {@code receiverClass} and
  58      * creates a transient native wrapper of the same type as {@code wrappedReceiver} for subsequent invocations of the
  59      * method - it will be combined into the returned invocation as an argument filter on the receiver.
  60      * @return a guarded invocation representing the operation at the call site when performed on a JavaScript primitive
  61      * type {@code receiverClass}.
  62      */
  63     public static GuardedInvocation lookupPrimitive(final LinkRequest request, final Class<?> receiverClass,
  64                                                     final ScriptObject wrappedReceiver, final MethodHandle wrapFilter) {
  65         return lookupPrimitive(request, Guards.getInstanceOfGuard(receiverClass), wrappedReceiver, wrapFilter);
  66     }
  67 
  68     /**
  69      * Returns a guarded invocation representing the linkage for a dynamic operation on a primitive Java value.
  70      * @param request the link request for the dynamic call site.
  71      * @param guard an explicit guard that will be used for the returned guarded invocation.
  72      * @param wrappedReceiver a transient JavaScript native wrapper object created as the object proxy for the primitive
  73      * value; see ECMAScript 5.1, section 8.7.1 for discussion of using {@code [[Get]]} on a property reference with a
  74      * primitive base value. This instance will be used to delegate actual lookup.
  75      * @param wrapFilter A method handle that takes a primitive value of type guarded by the {@code guard} and
  76      * creates a transient native wrapper of the same type as {@code wrappedReceiver} for subsequent invocations of the
  77      * method - it will be combined into the returned invocation as an argument filter on the receiver.
  78      * @return a guarded invocation representing the operation at the call site when performed on a JavaScript primitive
  79      * type (that is implied by both {@code guard} and {@code wrappedReceiver}).
  80      */
  81     public static GuardedInvocation lookupPrimitive(final LinkRequest request, final MethodHandle guard,
  82                                                     final ScriptObject wrappedReceiver, final MethodHandle wrapFilter) {
  83         final CallSiteDescriptor desc = request.getCallSiteDescriptor();
  84         final String operator = CallSiteDescriptorFactory.tokenizeOperators(desc).get(0);
  85         if ("setProp".equals(operator) || "setElem".equals(operator)) {
  86             MethodType type = desc.getMethodType();
  87             MethodHandle method = MH.asType(Lookup.EMPTY_SETTER, MH.type(void.class, Object.class, type.parameterType(1)));
  88             if (type.parameterCount() == 3) {
  89                 method = MH.dropArguments(method, 2, type.parameterType(2));
  90             }
  91             return new GuardedInvocation(method, guard);
  92         }
  93 
  94         if(desc.getNameTokenCount() > 2) {
  95             final String name = desc.getNameToken(CallSiteDescriptor.NAME_OPERAND);
  96             if(wrappedReceiver.findProperty(name, true) == null) {
  97                 // Give up early, give chance to BeanLinker and NashornBottomLinker to deal with it.
  98                 return null;
  99             }
 100         }
 101         final GuardedInvocation link = wrappedReceiver.lookup(desc, request);
 102         if (link != null) {
 103             MethodHandle method = link.getInvocation();
 104             final Class<?> receiverType = method.type().parameterType(0);
 105             if (receiverType != Object.class) {
 106                 final MethodType wrapType = wrapFilter.type();
 107                 assert receiverType.isAssignableFrom(wrapType.returnType());
 108                 method = MH.filterArguments(method, 0, MH.asType(wrapFilter, wrapType.changeReturnType(receiverType)));
 109             }
 110             return new GuardedInvocation(method, guard, link.getSwitchPoint());
 111         }
 112         return null;
 113     }
 114 }