NashornBeansLinker.java revision 1705:59d31c4e3f77
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 java.util.function.Supplier; 36import jdk.dynalink.CallSiteDescriptor; 37import jdk.dynalink.NamedOperation; 38import jdk.dynalink.SecureLookupSupplier; 39import jdk.dynalink.StandardOperation; 40import jdk.dynalink.beans.BeansLinker; 41import jdk.dynalink.linker.ConversionComparator.Comparison; 42import jdk.dynalink.linker.GuardedInvocation; 43import jdk.dynalink.linker.GuardingDynamicLinker; 44import jdk.dynalink.linker.LinkRequest; 45import jdk.dynalink.linker.LinkerServices; 46import jdk.dynalink.linker.MethodHandleTransformer; 47import jdk.dynalink.linker.support.DefaultInternalObjectFilter; 48import jdk.dynalink.linker.support.Lookup; 49import jdk.nashorn.api.scripting.ScriptUtils; 50import jdk.nashorn.internal.runtime.ConsString; 51import jdk.nashorn.internal.runtime.Context; 52import jdk.nashorn.internal.runtime.ScriptObject; 53import jdk.nashorn.internal.runtime.options.Options; 54 55/** 56 * This linker delegates to a {@code BeansLinker} but passes it a special linker services object that has a modified 57 * {@code compareConversion} method that favors conversion of {@link ConsString} to either {@link String} or 58 * {@link CharSequence}. It also provides a {@link #createHiddenObjectFilter()} method for use with bootstrap that will 59 * ensure that we never pass internal engine objects that should not be externally observable (currently ConsString and 60 * ScriptObject) to Java APIs, but rather that we flatten it into a String. We can't just add this functionality as 61 * custom converters via {@code GuaardingTypeConverterFactory}, since they are not consulted when 62 * the target method handle parameter signature is {@code Object}. This linker also makes sure that primitive 63 * {@link String} operations can be invoked on a {@link ConsString}, and allows invocation of objects implementing 64 * the {@link FunctionalInterface} attribute. 65 */ 66public class NashornBeansLinker implements GuardingDynamicLinker { 67 // System property to control whether to wrap ScriptObject->ScriptObjectMirror for 68 // Object type arguments of Java method calls, field set and array set. 69 private static final boolean MIRROR_ALWAYS = Options.getBooleanProperty("nashorn.mirror.always", true); 70 71 private static final MethodHandle EXPORT_ARGUMENT; 72 private static final MethodHandle IMPORT_RESULT; 73 private static final MethodHandle FILTER_CONSSTRING; 74 75 static { 76 final Lookup lookup = new Lookup(MethodHandles.lookup()); 77 EXPORT_ARGUMENT = lookup.findOwnStatic("exportArgument", Object.class, Object.class); 78 IMPORT_RESULT = lookup.findOwnStatic("importResult", Object.class, Object.class); 79 FILTER_CONSSTRING = lookup.findOwnStatic("consStringFilter", Object.class, Object.class); 80 } 81 82 // cache of @FunctionalInterface method of implementor classes 83 private static final ClassValue<String> FUNCTIONAL_IFACE_METHOD_NAME = new ClassValue<String>() { 84 @Override 85 protected String computeValue(final Class<?> type) { 86 return findFunctionalInterfaceMethodName(type); 87 } 88 }; 89 90 private final BeansLinker beansLinker; 91 92 NashornBeansLinker(final BeansLinker beansLinker) { 93 this.beansLinker = beansLinker; 94 } 95 96 @Override 97 public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception { 98 final Object self = linkRequest.getReceiver(); 99 final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor(); 100 if (self instanceof ConsString) { 101 // In order to treat ConsString like a java.lang.String we need a link request with a string receiver. 102 final Object[] arguments = linkRequest.getArguments(); 103 arguments[0] = ""; 104 final LinkRequest forgedLinkRequest = linkRequest.replaceArguments(desc, arguments); 105 final GuardedInvocation invocation = getGuardedInvocation(beansLinker, forgedLinkRequest, linkerServices); 106 // If an invocation is found we add a filter that makes it work for both Strings and ConsStrings. 107 return invocation == null ? null : invocation.filterArguments(0, FILTER_CONSSTRING); 108 } 109 110 if (self != null && NamedOperation.getBaseOperation(desc.getOperation()) == StandardOperation.CALL) { 111 // Support CALL on any object that supports some @FunctionalInterface 112 // annotated interface. This way Java method, constructor references or 113 // implementations of java.util.function.* interfaces can be called as though 114 // those are script functions. 115 final String name = getFunctionalInterfaceMethodName(self.getClass()); 116 if (name != null) { 117 final MethodType callType = desc.getMethodType(); 118 // drop callee (Undefined ScriptFunction) and change the request to be CALL_METHOD:<name> 119 final CallSiteDescriptor newDesc = new CallSiteDescriptor( 120 NashornCallSiteDescriptor.getLookupInternal(desc), 121 new NamedOperation(StandardOperation.CALL_METHOD, name), 122 desc.getMethodType().dropParameterTypes(1, 2)); 123 final GuardedInvocation gi = getGuardedInvocation(beansLinker, 124 linkRequest.replaceArguments(newDesc, linkRequest.getArguments()), 125 new NashornBeansLinkerServices(linkerServices)); 126 127 // drop 'thiz' passed from the script. 128 return gi.replaceMethods( 129 MH.dropArguments(linkerServices.filterInternalObjects(gi.getInvocation()), 1, callType.parameterType(1)), 130 gi.getGuard()); 131 } 132 } 133 return getGuardedInvocation(beansLinker, linkRequest, linkerServices); 134 } 135 136 /** 137 * Delegates to the specified linker but injects its linker services wrapper so that it will apply all special 138 * conversions that this class does. 139 * @param delegateLinker the linker to which the actual work is delegated to. 140 * @param linkRequest the delegated link request 141 * @param linkerServices the original link services that will be augmented with special conversions 142 * @return the guarded invocation from the delegate, possibly augmented with special conversions 143 * @throws Exception if the delegate throws an exception 144 */ 145 public static GuardedInvocation getGuardedInvocation(final GuardingDynamicLinker delegateLinker, final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception { 146 return delegateLinker.getGuardedInvocation(linkRequest, new NashornBeansLinkerServices(linkerServices)); 147 } 148 149 @SuppressWarnings("unused") 150 private static Object exportArgument(final Object arg) { 151 return exportArgument(arg, MIRROR_ALWAYS); 152 } 153 154 static Object exportArgument(final Object arg, final boolean mirrorAlways) { 155 if (arg instanceof ConsString) { 156 return arg.toString(); 157 } else if (mirrorAlways && arg instanceof ScriptObject) { 158 return ScriptUtils.wrap(arg); 159 } else { 160 return arg; 161 } 162 } 163 164 @SuppressWarnings("unused") 165 private static Object importResult(final Object arg) { 166 return ScriptUtils.unwrap(arg); 167 } 168 169 @SuppressWarnings("unused") 170 private static Object consStringFilter(final Object arg) { 171 return arg instanceof ConsString ? arg.toString() : arg; 172 } 173 174 private static String findFunctionalInterfaceMethodName(final Class<?> clazz) { 175 if (clazz == null) { 176 return null; 177 } 178 179 for (final Class<?> iface : clazz.getInterfaces()) { 180 // check accessibility up-front 181 if (! Context.isAccessibleClass(iface)) { 182 continue; 183 } 184 185 // check for @FunctionalInterface 186 if (iface.isAnnotationPresent(FunctionalInterface.class)) { 187 // return the first abstract method 188 for (final Method m : iface.getMethods()) { 189 if (Modifier.isAbstract(m.getModifiers()) && !isOverridableObjectMethod(m)) { 190 return m.getName(); 191 } 192 } 193 } 194 } 195 196 // did not find here, try super class 197 return findFunctionalInterfaceMethodName(clazz.getSuperclass()); 198 } 199 200 // is this an overridable java.lang.Object method? 201 private static boolean isOverridableObjectMethod(final Method m) { 202 switch (m.getName()) { 203 case "equals": 204 if (m.getReturnType() == boolean.class) { 205 final Class<?>[] params = m.getParameterTypes(); 206 return params.length == 1 && params[0] == Object.class; 207 } 208 return false; 209 case "hashCode": 210 return m.getReturnType() == int.class && m.getParameterCount() == 0; 211 case "toString": 212 return m.getReturnType() == String.class && m.getParameterCount() == 0; 213 } 214 return false; 215 } 216 217 // Returns @FunctionalInterface annotated interface's single abstract 218 // method name. If not found, returns null. 219 static String getFunctionalInterfaceMethodName(final Class<?> clazz) { 220 return FUNCTIONAL_IFACE_METHOD_NAME.get(clazz); 221 } 222 223 static MethodHandleTransformer createHiddenObjectFilter() { 224 return new DefaultInternalObjectFilter(EXPORT_ARGUMENT, MIRROR_ALWAYS ? IMPORT_RESULT : null); 225 } 226 227 private static class NashornBeansLinkerServices implements LinkerServices { 228 private final LinkerServices linkerServices; 229 230 NashornBeansLinkerServices(final LinkerServices linkerServices) { 231 this.linkerServices = linkerServices; 232 } 233 234 @Override 235 public MethodHandle asType(final MethodHandle handle, final MethodType fromType) { 236 return linkerServices.asType(handle, fromType); 237 } 238 239 @Override 240 public MethodHandle getTypeConverter(final Class<?> sourceType, final Class<?> targetType) { 241 return linkerServices.getTypeConverter(sourceType, targetType); 242 } 243 244 @Override 245 public boolean canConvert(final Class<?> from, final Class<?> to) { 246 return linkerServices.canConvert(from, to); 247 } 248 249 @Override 250 public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest) throws Exception { 251 return linkerServices.getGuardedInvocation(linkRequest); 252 } 253 254 @Override 255 public Comparison compareConversion(final Class<?> sourceType, final Class<?> targetType1, final Class<?> targetType2) { 256 if (sourceType == ConsString.class) { 257 if (String.class == targetType1 || CharSequence.class == targetType1) { 258 return Comparison.TYPE_1_BETTER; 259 } 260 261 if (String.class == targetType2 || CharSequence.class == targetType2) { 262 return Comparison.TYPE_2_BETTER; 263 } 264 } 265 return linkerServices.compareConversion(sourceType, targetType1, targetType2); 266 } 267 268 @Override 269 public MethodHandle filterInternalObjects(final MethodHandle target) { 270 return linkerServices.filterInternalObjects(target); 271 } 272 273 @Override 274 public <T> T getWithLookup(final Supplier<T> operation, final SecureLookupSupplier lookupSupplier) { 275 return linkerServices.getWithLookup(operation, lookupSupplier); 276 } 277 } 278} 279