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.MethodHandles; 32 import java.lang.reflect.Modifier; 33 import java.util.Deque; 34 import java.util.List; 35 import java.util.Map; 36 import javax.script.Bindings; 37 import jdk.internal.dynalink.CallSiteDescriptor; 38 import jdk.internal.dynalink.linker.ConversionComparator; 39 import jdk.internal.dynalink.linker.GuardedInvocation; 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.linker.TypeBasedGuardingDynamicLinker; 44 import jdk.internal.dynalink.support.Guards; 45 import jdk.nashorn.api.scripting.JSObject; 46 import jdk.nashorn.api.scripting.ScriptObjectMirror; 47 import jdk.nashorn.internal.objects.NativeArray; 48 import jdk.nashorn.internal.runtime.Context; 49 import jdk.nashorn.internal.runtime.JSType; 50 import jdk.nashorn.internal.runtime.ScriptFunction; 51 import jdk.nashorn.internal.runtime.ScriptObject; 52 import jdk.nashorn.internal.runtime.Undefined; 53 54 /** 55 * This is the main dynamic linker for Nashorn. It is used for linking all {@link ScriptObject} and its subclasses (this 56 * includes {@link ScriptFunction} and its subclasses) as well as {@link Undefined}. 57 */ 58 final class NashornLinker implements TypeBasedGuardingDynamicLinker, GuardingTypeConverterFactory, ConversionComparator { 59 private static final ClassValue<MethodHandle> ARRAY_CONVERTERS = new ClassValue<MethodHandle>() { 60 @Override 61 protected MethodHandle computeValue(Class<?> type) { 62 return createArrayConverter(type); 63 } 64 }; 65 66 /** 67 * Returns true if {@code ScriptObject} is assignable from {@code type}, or it is {@code Undefined}. 68 */ 69 @Override 70 public boolean canLinkType(final Class<?> type) { 71 return canLinkTypeStatic(type); 72 } 73 74 static boolean canLinkTypeStatic(final Class<?> type) { 75 return ScriptObject.class.isAssignableFrom(type) || Undefined.class == type; 76 } 77 78 @Override 79 public GuardedInvocation getGuardedInvocation(final LinkRequest request, final LinkerServices linkerServices) throws Exception { 80 final LinkRequest requestWithoutContext = request.withoutRuntimeContext(); // Nashorn has no runtime context 81 final Object self = requestWithoutContext.getReceiver(); 82 final CallSiteDescriptor desc = requestWithoutContext.getCallSiteDescriptor(); 83 84 if (desc.getNameTokenCount() < 2 || !"dyn".equals(desc.getNameToken(CallSiteDescriptor.SCHEME))) { 85 // We only support standard "dyn:*[:*]" operations 86 return null; 87 } 88 89 final GuardedInvocation inv; 90 if (self instanceof ScriptObject) { 91 inv = ((ScriptObject)self).lookup(desc, request); 92 } else if (self instanceof Undefined) { 93 inv = Undefined.lookup(desc); 94 } else { 95 throw new AssertionError(); // Should never reach here. 96 } 97 98 return Bootstrap.asType(inv, linkerServices, desc); 99 } 100 101 @Override 102 public GuardedInvocation convertToType(final Class<?> sourceType, final Class<?> targetType) throws Exception { 103 final GuardedInvocation gi = convertToTypeNoCast(sourceType, targetType); 104 return gi == null ? null : gi.asType(MH.type(targetType, sourceType)); 105 } 106 107 /** 108 * Main part of the implementation of {@link GuardingTypeConverterFactory#convertToType(Class, Class)} that doesn't 109 * care about adapting the method signature; that's done by the invoking method. Returns either a built-in 110 * conversion to primitive (or primitive wrapper) Java types or to String, or a just-in-time generated converter to 111 * a SAM type (if the target type is a SAM type). 112 * @param sourceType the source type 113 * @param targetType the target type 114 * @return a guarded invocation that converts from the source type to the target type. 115 * @throws Exception if something goes wrong 116 */ 117 private static GuardedInvocation convertToTypeNoCast(final Class<?> sourceType, final Class<?> targetType) throws Exception { 118 final MethodHandle mh = JavaArgumentConverters.getConverter(targetType); 119 if (mh != null) { 120 return new GuardedInvocation(mh, canLinkTypeStatic(sourceType) ? null : IS_NASHORN_OR_UNDEFINED_TYPE); 121 } 122 123 final GuardedInvocation arrayConverter = getArrayConverter(sourceType, targetType); 124 if(arrayConverter != null) { 125 return arrayConverter; 126 } 127 128 final GuardedInvocation mapConverter = getMirrorConverter(sourceType, targetType); 129 if(mapConverter != null) { 130 return mapConverter; 131 } 132 133 return getSamTypeConverter(sourceType, targetType); 134 } 135 136 /** 137 * Returns a guarded invocation that converts from a source type that is ScriptFunction, or a subclass or a 138 * superclass of it) to a SAM type. 139 * @param sourceType the source type (presumably ScriptFunction or a subclass or a superclass of it) 140 * @param targetType the target type (presumably a SAM type) 141 * @return a guarded invocation that converts from the source type to the target SAM type. null is returned if 142 * either the source type is neither ScriptFunction, nor a subclass, nor a superclass of it, or if the target type 143 * is not a SAM type. 144 * @throws Exception if something goes wrong; generally, if there's an issue with creation of the SAM proxy type 145 * constructor. 146 */ 147 private static GuardedInvocation getSamTypeConverter(final Class<?> sourceType, final Class<?> targetType) throws Exception { 148 // If source type is more generic than ScriptFunction class, we'll need to use a guard 149 final boolean isSourceTypeGeneric = sourceType.isAssignableFrom(ScriptFunction.class); 150 151 if ((isSourceTypeGeneric || ScriptFunction.class.isAssignableFrom(sourceType)) && isAutoConvertibleFromFunction(targetType)) { 152 final MethodHandle ctor = JavaAdapterFactory.getConstructor(ScriptFunction.class, targetType); 153 assert ctor != null; // if isAutoConvertibleFromFunction() returned true, then ctor must exist. 154 return new GuardedInvocation(ctor, isSourceTypeGeneric ? IS_SCRIPT_FUNCTION : null); 155 } 156 return null; 157 } 158 159 /** 160 * Returns a guarded invocation that converts from a source type that is NativeArray to a Java array or List or 161 * Deque type. 162 * @param sourceType the source type (presumably NativeArray a superclass of it) 163 * @param targetType the target type (presumably an array type, or List or Deque) 164 * @return a guarded invocation that converts from the source type to the target type. null is returned if 165 * either the source type is neither NativeArray, nor a superclass of it, or if the target type is not an array 166 * type, List, or Deque. 167 */ 168 private static GuardedInvocation getArrayConverter(final Class<?> sourceType, final Class<?> targetType) { 169 final boolean isSourceTypeNativeArray = sourceType == NativeArray.class; 170 // If source type is more generic than ScriptFunction class, we'll need to use a guard 171 final boolean isSourceTypeGeneric = !isSourceTypeNativeArray && sourceType.isAssignableFrom(NativeArray.class); 172 173 if (isSourceTypeNativeArray || isSourceTypeGeneric) { 174 final MethodHandle guard = isSourceTypeGeneric ? IS_NATIVE_ARRAY : null; 175 if(targetType.isArray()) { 176 return new GuardedInvocation(ARRAY_CONVERTERS.get(targetType), guard); 177 } 178 if(targetType == List.class) { 179 return new GuardedInvocation(JSType.TO_JAVA_LIST.methodHandle(), guard); 180 } 181 if(targetType == Deque.class) { 182 return new GuardedInvocation(JSType.TO_JAVA_DEQUE.methodHandle(), guard); 183 } 184 } 185 return null; 186 } 187 188 private static MethodHandle createArrayConverter(final Class<?> type) { 189 assert type.isArray(); 190 final MethodHandle converter = MH.insertArguments(JSType.TO_JAVA_ARRAY.methodHandle(), 1, type.getComponentType()); 191 return MH.asType(converter, converter.type().changeReturnType(type)); 192 } 193 194 private static GuardedInvocation getMirrorConverter(Class<?> sourceType, Class<?> targetType) { 195 // Could've also used (targetType.isAssignableFrom(ScriptObjectMirror.class) && targetType != Object.class) but 196 // it's probably better to explicitly spell out the supported target types 197 if (targetType == Map.class || targetType == Bindings.class || targetType == JSObject.class || targetType == ScriptObjectMirror.class) { 198 if(ScriptObject.class.isAssignableFrom(sourceType)) { 199 return new GuardedInvocation(CREATE_MIRROR, null); 200 } 201 return new GuardedInvocation(CREATE_MIRROR, IS_SCRIPT_OBJECT); 202 } 203 return null; 204 } 205 206 private static boolean isAutoConvertibleFromFunction(final Class<?> clazz) { 207 return isAbstractClass(clazz) && !ScriptObject.class.isAssignableFrom(clazz) && 208 JavaAdapterFactory.isAutoConvertibleFromFunction(clazz); 209 } 210 211 /** 212 * Utility method used by few other places in the code. Tests if the class has the abstract modifier and is not an 213 * array class. For some reason, array classes have the abstract modifier set in HotSpot JVM, and we don't want to 214 * treat array classes as abstract. 215 * @param clazz the inspected class 216 * @return true if the class is abstract and is not an array type. 217 */ 218 static boolean isAbstractClass(final Class<?> clazz) { 219 return Modifier.isAbstract(clazz.getModifiers()) && !clazz.isArray(); 220 } 221 222 223 @Override 224 public Comparison compareConversion(final Class<?> sourceType, final Class<?> targetType1, final Class<?> targetType2) { 225 if(sourceType == NativeArray.class) { 226 // Prefer lists, as they're less costly to create than arrays. 227 if(isList(targetType1)) { 228 if(!isList(targetType2)) { 229 return Comparison.TYPE_1_BETTER; 230 } 231 } else if(isList(targetType2)) { 232 return Comparison.TYPE_2_BETTER; 233 } 234 // Then prefer arrays 235 if(targetType1.isArray()) { 236 if(!targetType2.isArray()) { 237 return Comparison.TYPE_1_BETTER; 238 } 239 } else if(targetType2.isArray()) { 240 return Comparison.TYPE_2_BETTER; 241 } 242 } 243 if(ScriptObject.class.isAssignableFrom(sourceType)) { 244 // Prefer interfaces 245 if(targetType1.isInterface()) { 246 if(!targetType2.isInterface()) { 247 return Comparison.TYPE_1_BETTER; 248 } 249 } else if(targetType2.isInterface()) { 250 return Comparison.TYPE_2_BETTER; 251 } 252 } 253 return Comparison.INDETERMINATE; 254 } 255 256 private static boolean isList(Class<?> clazz) { 257 return clazz == List.class || clazz == Deque.class; 258 } 259 260 private static final MethodHandle IS_SCRIPT_OBJECT = Guards.isInstance(ScriptObject.class, MH.type(Boolean.TYPE, Object.class)); 261 private static final MethodHandle IS_SCRIPT_FUNCTION = Guards.isInstance(ScriptFunction.class, MH.type(Boolean.TYPE, Object.class)); 262 private static final MethodHandle IS_NATIVE_ARRAY = Guards.isOfClass(NativeArray.class, MH.type(Boolean.TYPE, Object.class)); 263 264 private static final MethodHandle IS_NASHORN_OR_UNDEFINED_TYPE = findOwnMH("isNashornTypeOrUndefined", Boolean.TYPE, Object.class); 265 private static final MethodHandle CREATE_MIRROR = findOwnMH("createMirror", Object.class, Object.class); 266 267 @SuppressWarnings("unused") 268 private static boolean isNashornTypeOrUndefined(final Object obj) { 269 return obj instanceof ScriptObject || obj instanceof Undefined; 270 } 271 272 @SuppressWarnings("unused") 273 private static Object createMirror(final Object obj) { 274 return ScriptObjectMirror.wrap(obj, Context.getGlobal()); 275 } 276 277 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 278 return MH.findStatic(MethodHandles.lookup(), NashornLinker.class, name, MH.type(rtype, types)); 279 } 280 } 281 --- EOF ---