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 static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
  30 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;
  31 
  32 import java.lang.invoke.MethodHandle;
  33 import java.util.HashMap;
  34 import java.util.Map;
  35 import jdk.internal.dynalink.CallSiteDescriptor;
  36 import jdk.internal.dynalink.beans.BeansLinker;
  37 import jdk.internal.dynalink.linker.GuardedInvocation;
  38 import jdk.internal.dynalink.linker.GuardedTypeConversion;
  39 import jdk.internal.dynalink.linker.GuardingDynamicLinker;
  40 import jdk.internal.dynalink.linker.GuardingTypeConverterFactory;
  41 import jdk.internal.dynalink.linker.LinkRequest;
  42 import jdk.internal.dynalink.linker.LinkerServices;
  43 import jdk.internal.dynalink.support.Guards;
  44 import jdk.nashorn.internal.codegen.types.Type;
  45 import jdk.nashorn.internal.runtime.JSType;
  46 import jdk.nashorn.internal.runtime.ScriptRuntime;
  47 import jdk.nashorn.internal.runtime.UnwarrantedOptimismException;
  48 
  49 /**
  50  * Nashorn bottom linker; used as a last-resort catch-all linker for all linking requests that fall through all other
  51  * linkers (see how {@link Bootstrap} class configures the dynamic linker in its static initializer). It will throw
  52  * appropriate ECMAScript errors for attempts to invoke operations on {@code null}, link no-op property getters and
  53  * setters for Java objects that couldn't be linked by any other linker, and throw appropriate ECMAScript errors for
  54  * attempts to invoke arbitrary Java objects as functions or constructors.
  55  */
  56 final class NashornBottomLinker implements GuardingDynamicLinker, GuardingTypeConverterFactory {
  57 
  58     @Override
  59     public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices)
  60             throws Exception {
  61         final Object self = linkRequest.getReceiver();
  62 
  63         if (self == null) {
  64             return linkNull(linkRequest);
  65         }
  66 
  67         // None of the objects that can be linked by NashornLinker should ever reach here. Basically, anything below
  68         // this point is a generic Java bean. Therefore, reaching here with a ScriptObject is a Nashorn bug.
  69         assert isExpectedObject(self) : "Couldn't link " + linkRequest.getCallSiteDescriptor() + " for " + self.getClass().getName();
  70 
  71         return linkBean(linkRequest, linkerServices);
  72     }
  73 
  74     private static final MethodHandle EMPTY_PROP_GETTER =
  75             MH.dropArguments(MH.constant(Object.class, UNDEFINED), 0, Object.class);
  76     private static final MethodHandle EMPTY_ELEM_GETTER =
  77             MH.dropArguments(EMPTY_PROP_GETTER, 0, Object.class);
  78     private static final MethodHandle EMPTY_PROP_SETTER =
  79             MH.asType(EMPTY_ELEM_GETTER, EMPTY_ELEM_GETTER.type().changeReturnType(void.class));
  80     private static final MethodHandle EMPTY_ELEM_SETTER =
  81             MH.dropArguments(EMPTY_PROP_SETTER, 0, Object.class);
  82 
  83     private static GuardedInvocation linkBean(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
  84         final NashornCallSiteDescriptor desc = (NashornCallSiteDescriptor)linkRequest.getCallSiteDescriptor();
  85         final Object self = linkRequest.getReceiver();
  86         final String operator = desc.getFirstOperator();
  87         switch (operator) {
  88         case "new":
  89             if(BeansLinker.isDynamicConstructor(self)) {
  90                 throw typeError("no.constructor.matches.args", ScriptRuntime.safeToString(self));
  91             }
  92             if(BeansLinker.isDynamicMethod(self)) {
  93                 throw typeError("method.not.constructor", ScriptRuntime.safeToString(self));
  94             }
  95             throw typeError("not.a.function", ScriptRuntime.safeToString(self));
  96         case "call":
  97             if(BeansLinker.isDynamicConstructor(self)) {
  98                 throw typeError("constructor.requires.new", ScriptRuntime.safeToString(self));
  99             }
 100             if(BeansLinker.isDynamicMethod(self)) {
 101                 throw typeError("no.method.matches.args", ScriptRuntime.safeToString(self));
 102             }
 103             throw typeError("not.a.function", ScriptRuntime.safeToString(self));
 104         case "callMethod":
 105         case "getMethod":
 106             throw typeError("no.such.function", getArgument(linkRequest), ScriptRuntime.safeToString(self));
 107         case "getProp":
 108         case "getElem":
 109             if(NashornCallSiteDescriptor.isOptimistic(desc)) {
 110                 throw new UnwarrantedOptimismException(UNDEFINED, NashornCallSiteDescriptor.getProgramPoint(desc), Type.OBJECT);
 111             }
 112             if (desc.getOperand() != null) {
 113                 return getInvocation(EMPTY_PROP_GETTER, self, linkerServices, desc);
 114             }
 115             return getInvocation(EMPTY_ELEM_GETTER, self, linkerServices, desc);
 116         case "setProp":
 117         case "setElem": {
 118             final boolean strict = NashornCallSiteDescriptor.isStrict(desc);
 119             if (strict) {
 120                 throw typeError("cant.set.property", getArgument(linkRequest), ScriptRuntime.safeToString(self));
 121             }
 122             if (desc.getOperand() != null) {
 123                 return getInvocation(EMPTY_PROP_SETTER, self, linkerServices, desc);
 124             }
 125             return getInvocation(EMPTY_ELEM_SETTER, self, linkerServices, desc);
 126         }
 127         default:
 128             break;
 129         }
 130         throw new AssertionError("unknown call type " + desc);
 131     }
 132 
 133     @Override
 134     public GuardedTypeConversion convertToType(final Class<?> sourceType, final Class<?> targetType) throws Exception {
 135         final GuardedInvocation gi = convertToTypeNoCast(sourceType, targetType);
 136         return gi == null ? null : new GuardedTypeConversion(gi.asType(MH.type(targetType, sourceType)), true);
 137     }
 138 
 139     /**
 140      * Main part of the implementation of {@link GuardingTypeConverterFactory#convertToType(Class, Class)} that doesn't
 141      * care about adapting the method signature; that's done by the invoking method. Returns conversion from Object to String/number/boolean (JS primitive types).
 142      * @param sourceType the source type
 143      * @param targetType the target type
 144      * @return a guarded invocation that converts from the source type to the target type.
 145      * @throws Exception if something goes wrong
 146      */
 147     private static GuardedInvocation convertToTypeNoCast(final Class<?> sourceType, final Class<?> targetType) throws Exception {
 148         final MethodHandle mh = CONVERTERS.get(targetType);
 149         if (mh != null) {
 150             return new GuardedInvocation(mh);
 151         }
 152 
 153         return null;
 154     }
 155 
 156     private static GuardedInvocation getInvocation(final MethodHandle handle, final Object self, final LinkerServices linkerServices, final CallSiteDescriptor desc) {
 157         return Bootstrap.asTypeSafeReturn(new GuardedInvocation(handle, Guards.getClassGuard(self.getClass())), linkerServices, desc);
 158     }
 159 
 160     // Used solely in an assertion to figure out if the object we get here is something we in fact expect. Objects
 161     // linked by NashornLinker should never reach here.
 162     private static boolean isExpectedObject(final Object obj) {
 163         return !(NashornLinker.canLinkTypeStatic(obj.getClass()));
 164     }
 165 
 166     private static GuardedInvocation linkNull(final LinkRequest linkRequest) {
 167         final NashornCallSiteDescriptor desc = (NashornCallSiteDescriptor)linkRequest.getCallSiteDescriptor();
 168         final String operator = desc.getFirstOperator();
 169         switch (operator) {
 170         case "new":
 171         case "call":
 172             throw typeError("not.a.function", "null");
 173         case "callMethod":
 174         case "getMethod":
 175             throw typeError("no.such.function", getArgument(linkRequest), "null");
 176         case "getProp":
 177         case "getElem":
 178             throw typeError("cant.get.property", getArgument(linkRequest), "null");
 179         case "setProp":
 180         case "setElem":
 181             throw typeError("cant.set.property", getArgument(linkRequest), "null");
 182         default:
 183             break;
 184         }
 185         throw new AssertionError("unknown call type " + desc);
 186     }
 187 
 188     private static final Map<Class<?>, MethodHandle> CONVERTERS = new HashMap<>();
 189     static {
 190         CONVERTERS.put(boolean.class, JSType.TO_BOOLEAN.methodHandle());
 191         CONVERTERS.put(double.class, JSType.TO_NUMBER.methodHandle());
 192         CONVERTERS.put(int.class, JSType.TO_INTEGER.methodHandle());
 193         CONVERTERS.put(long.class, JSType.TO_LONG.methodHandle());
 194         CONVERTERS.put(String.class, JSType.TO_STRING.methodHandle());
 195     }
 196 
 197     private static String getArgument(final LinkRequest linkRequest) {
 198         final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
 199         if (desc.getNameTokenCount() > 2) {
 200             return desc.getNameToken(2);
 201         }
 202         return ScriptRuntime.safeToString(linkRequest.getArguments()[1]);
 203     }
 204 }