NashornBeansLinker.java revision 1551:f3b883bec2d0
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 26package jdk.nashorn.internal.runtime.linker; 27 28import static jdk.nashorn.internal.lookup.Lookup.MH; 29 30import java.lang.invoke.MethodHandle; 31import java.lang.invoke.MethodHandles; 32import java.lang.invoke.MethodType; 33import java.lang.reflect.Method; 34import java.lang.reflect.Modifier; 35import jdk.dynalink.CallSiteDescriptor; 36import jdk.dynalink.NamedOperation; 37import jdk.dynalink.StandardOperation; 38import jdk.dynalink.beans.BeansLinker; 39import jdk.dynalink.linker.ConversionComparator.Comparison; 40import jdk.dynalink.linker.GuardedInvocation; 41import jdk.dynalink.linker.GuardingDynamicLinker; 42import jdk.dynalink.linker.LinkRequest; 43import jdk.dynalink.linker.LinkerServices; 44import jdk.dynalink.linker.MethodHandleTransformer; 45import jdk.dynalink.linker.support.DefaultInternalObjectFilter; 46import jdk.dynalink.linker.support.Lookup; 47import jdk.nashorn.api.scripting.ScriptUtils; 48import jdk.nashorn.internal.runtime.ConsString; 49import jdk.nashorn.internal.runtime.Context; 50import jdk.nashorn.internal.runtime.ScriptObject; 51import jdk.nashorn.internal.runtime.options.Options; 52 53/** 54 * This linker delegates to a {@code BeansLinker} but passes it a special linker services object that has a modified 55 * {@code compareConversion} method that favors conversion of {@link ConsString} to either {@link String} or 56 * {@link CharSequence}. It also provides a {@link #createHiddenObjectFilter()} method for use with bootstrap that will 57 * ensure that we never pass internal engine objects that should not be externally observable (currently ConsString and 58 * ScriptObject) to Java APIs, but rather that we flatten it into a String. We can't just add this functionality as 59 * custom converters via {@code GuaardingTypeConverterFactory}, since they are not consulted when 60 * the target method handle parameter signature is {@code Object}. This linker also makes sure that primitive 61 * {@link String} operations can be invoked on a {@link ConsString}, and allows invocation of objects implementing 62 * the {@link FunctionalInterface} attribute. 63 */ 64public class NashornBeansLinker implements GuardingDynamicLinker { 65 // System property to control whether to wrap ScriptObject->ScriptObjectMirror for 66 // Object type arguments of Java method calls, field set and array set. 67 private static final boolean MIRROR_ALWAYS = Options.getBooleanProperty("nashorn.mirror.always", true); 68 69 private static final MethodHandle EXPORT_ARGUMENT; 70 private static final MethodHandle IMPORT_RESULT; 71 private static final MethodHandle FILTER_CONSSTRING; 72 73 static { 74 final Lookup lookup = new Lookup(MethodHandles.lookup()); 75 EXPORT_ARGUMENT = lookup.findOwnStatic("exportArgument", Object.class, Object.class); 76 IMPORT_RESULT = lookup.findOwnStatic("importResult", Object.class, Object.class); 77 FILTER_CONSSTRING = lookup.findOwnStatic("consStringFilter", Object.class, Object.class); 78 } 79 80 // cache of @FunctionalInterface method of implementor classes 81 private static final ClassValue<String> FUNCTIONAL_IFACE_METHOD_NAME = new ClassValue<String>() { 82 @Override 83 protected String computeValue(final Class<?> type) { 84 return findFunctionalInterfaceMethodName(type); 85 } 86 }; 87 88 private final BeansLinker beansLinker = new BeansLinker(); 89 90 @Override 91 public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception { 92 final Object self = linkRequest.getReceiver(); 93 final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor(); 94 if (self instanceof ConsString) { 95 // In order to treat ConsString like a java.lang.String we need a link request with a string receiver. 96 final Object[] arguments = linkRequest.getArguments(); 97 arguments[0] = ""; 98 final LinkRequest forgedLinkRequest = linkRequest.replaceArguments(desc, arguments); 99 final GuardedInvocation invocation = getGuardedInvocation(beansLinker, forgedLinkRequest, linkerServices); 100 // If an invocation is found we add a filter that makes it work for both Strings and ConsStrings. 101 return invocation == null ? null : invocation.filterArguments(0, FILTER_CONSSTRING); 102 } 103 104 if (self != null && NamedOperation.getBaseOperation(desc.getOperation()) == StandardOperation.CALL) { 105 // Support CALL on any object that supports some @FunctionalInterface 106 // annotated interface. This way Java method, constructor references or 107 // implementations of java.util.function.* interfaces can be called as though 108 // those are script functions. 109 final String name = getFunctionalInterfaceMethodName(self.getClass()); 110 if (name != null) { 111 final MethodType callType = desc.getMethodType(); 112 // drop callee (Undefined ScriptFunction) and change the request to be CALL_METHOD:<name> 113 final CallSiteDescriptor newDesc = new CallSiteDescriptor( 114 NashornCallSiteDescriptor.getLookupInternal(desc), 115 new NamedOperation(StandardOperation.CALL_METHOD, name), 116 desc.getMethodType().dropParameterTypes(1, 2)); 117 final GuardedInvocation gi = getGuardedInvocation(beansLinker, 118 linkRequest.replaceArguments(newDesc, linkRequest.getArguments()), 119 new NashornBeansLinkerServices(linkerServices)); 120 121 // drop 'thiz' passed from the script. 122 return gi.replaceMethods( 123 MH.dropArguments(linkerServices.filterInternalObjects(gi.getInvocation()), 1, callType.parameterType(1)), 124 gi.getGuard()); 125 } 126 } 127 return getGuardedInvocation(beansLinker, linkRequest, linkerServices); 128 } 129 130 /** 131 * Delegates to the specified linker but injects its linker services wrapper so that it will apply all special 132 * conversions that this class does. 133 * @param delegateLinker the linker to which the actual work is delegated to. 134 * @param linkRequest the delegated link request 135 * @param linkerServices the original link services that will be augmented with special conversions 136 * @return the guarded invocation from the delegate, possibly augmented with special conversions 137 * @throws Exception if the delegate throws an exception 138 */ 139 public static GuardedInvocation getGuardedInvocation(final GuardingDynamicLinker delegateLinker, final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception { 140 return delegateLinker.getGuardedInvocation(linkRequest, new NashornBeansLinkerServices(linkerServices)); 141 } 142 143 @SuppressWarnings("unused") 144 private static Object exportArgument(final Object arg) { 145 return exportArgument(arg, MIRROR_ALWAYS); 146 } 147 148 static Object exportArgument(final Object arg, final boolean mirrorAlways) { 149 if (arg instanceof ConsString) { 150 return arg.toString(); 151 } else if (mirrorAlways && arg instanceof ScriptObject) { 152 return ScriptUtils.wrap((ScriptObject)arg); 153 } else { 154 return arg; 155 } 156 } 157 158 @SuppressWarnings("unused") 159 private static Object importResult(final Object arg) { 160 return ScriptUtils.unwrap(arg); 161 } 162 163 @SuppressWarnings("unused") 164 private static Object consStringFilter(final Object arg) { 165 return arg instanceof ConsString ? arg.toString() : arg; 166 } 167 168 private static String findFunctionalInterfaceMethodName(final Class<?> clazz) { 169 if (clazz == null) { 170 return null; 171 } 172 173 for (final Class<?> iface : clazz.getInterfaces()) { 174 // check accessibility up-front 175 if (! Context.isAccessibleClass(iface)) { 176 continue; 177 } 178 179 // check for @FunctionalInterface 180 if (iface.isAnnotationPresent(FunctionalInterface.class)) { 181 // return the first abstract method 182 for (final Method m : iface.getMethods()) { 183 if (Modifier.isAbstract(m.getModifiers())) { 184 return m.getName(); 185 } 186 } 187 } 188 } 189 190 // did not find here, try super class 191 return findFunctionalInterfaceMethodName(clazz.getSuperclass()); 192 } 193 194 // Returns @FunctionalInterface annotated interface's single abstract 195 // method name. If not found, returns null. 196 static String getFunctionalInterfaceMethodName(final Class<?> clazz) { 197 return FUNCTIONAL_IFACE_METHOD_NAME.get(clazz); 198 } 199 200 static MethodHandleTransformer createHiddenObjectFilter() { 201 return new DefaultInternalObjectFilter(EXPORT_ARGUMENT, MIRROR_ALWAYS ? IMPORT_RESULT : null); 202 } 203 204 private static class NashornBeansLinkerServices implements LinkerServices { 205 private final LinkerServices linkerServices; 206 207 NashornBeansLinkerServices(final LinkerServices linkerServices) { 208 this.linkerServices = linkerServices; 209 } 210 211 @Override 212 public MethodHandle asType(final MethodHandle handle, final MethodType fromType) { 213 return linkerServices.asType(handle, fromType); 214 } 215 216 @Override 217 public MethodHandle getTypeConverter(final Class<?> sourceType, final Class<?> targetType) { 218 return linkerServices.getTypeConverter(sourceType, targetType); 219 } 220 221 @Override 222 public boolean canConvert(final Class<?> from, final Class<?> to) { 223 return linkerServices.canConvert(from, to); 224 } 225 226 @Override 227 public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest) throws Exception { 228 return linkerServices.getGuardedInvocation(linkRequest); 229 } 230 231 @Override 232 public Comparison compareConversion(final Class<?> sourceType, final Class<?> targetType1, final Class<?> targetType2) { 233 if (sourceType == ConsString.class) { 234 if (String.class == targetType1 || CharSequence.class == targetType1) { 235 return Comparison.TYPE_1_BETTER; 236 } 237 238 if (String.class == targetType2 || CharSequence.class == targetType2) { 239 return Comparison.TYPE_2_BETTER; 240 } 241 } 242 return linkerServices.compareConversion(sourceType, targetType1, targetType2); 243 } 244 245 @Override 246 public MethodHandle filterInternalObjects(final MethodHandle target) { 247 return linkerServices.filterInternalObjects(target); 248 } 249 } 250} 251