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.api.scripting.ScriptUtils; 48 import jdk.nashorn.internal.objects.NativeArray; 49 import jdk.nashorn.internal.runtime.Context; 50 import jdk.nashorn.internal.runtime.JSType; 51 import jdk.nashorn.internal.runtime.ScriptFunction; 52 import jdk.nashorn.internal.runtime.ScriptObject; 53 import jdk.nashorn.internal.runtime.Undefined; 54 55 /** 56 * This is the main dynamic linker for Nashorn. It is used for linking all {@link ScriptObject} and its subclasses (this 57 * includes {@link ScriptFunction} and its subclasses) as well as {@link Undefined}. 58 */ 59 final class NashornLinker implements TypeBasedGuardingDynamicLinker, GuardingTypeConverterFactory, ConversionComparator { 60 private static final ClassValue<MethodHandle> ARRAY_CONVERTERS = new ClassValue<MethodHandle>() { 61 @Override 62 protected MethodHandle computeValue(Class<?> type) { 63 return createArrayConverter(type); 64 } 65 }; 66 67 /** 68 * Returns true if {@code ScriptObject} is assignable from {@code type}, or it is {@code Undefined}. 69 */ 70 @Override 71 public boolean canLinkType(final Class<?> type) { 72 return canLinkTypeStatic(type); 73 } 74 75 static boolean canLinkTypeStatic(final Class<?> type) { 76 return ScriptObject.class.isAssignableFrom(type) || Undefined.class == type; 77 } 78 79 @Override 80 public GuardedInvocation getGuardedInvocation(final LinkRequest request, final LinkerServices linkerServices) throws Exception { 81 final LinkRequest requestWithoutContext = request.withoutRuntimeContext(); // Nashorn has no runtime context 82 final Object self = requestWithoutContext.getReceiver(); 83 final CallSiteDescriptor desc = requestWithoutContext.getCallSiteDescriptor(); 84 85 if (desc.getNameTokenCount() < 2 || !"dyn".equals(desc.getNameToken(CallSiteDescriptor.SCHEME))) { 86 // We only support standard "dyn:*[:*]" operations 87 return null; 88 } 89 90 final GuardedInvocation inv; 91 if (self instanceof ScriptObject) { 92 inv = ((ScriptObject)self).lookup(desc, request); 93 } else if (self instanceof Undefined) { 94 inv = Undefined.lookup(desc); 95 } else { 96 throw new AssertionError(); // Should never reach here. 97 } 98 99 return Bootstrap.asType(inv, linkerServices, desc); 100 } 101 102 @Override 103 public GuardedInvocation convertToType(final Class<?> sourceType, final Class<?> targetType) throws Exception { 104 final GuardedInvocation gi = convertToTypeNoCast(sourceType, targetType); 105 return gi == null ? null : gi.asType(MH.type(targetType, sourceType)); 106 } 107 108 /** 109 * Main part of the implementation of {@link GuardingTypeConverterFactory#convertToType(Class, Class)} that doesn't 110 * care about adapting the method signature; that's done by the invoking method. Returns either a built-in 111 * conversion to primitive (or primitive wrapper) Java types or to String, or a just-in-time generated converter to 112 * a SAM type (if the target type is a SAM type). 113 * @param sourceType the source type 114 * @param targetType the target type 115 * @return a guarded invocation that converts from the source type to the target type. 116 * @throws Exception if something goes wrong 117 */ 118 private static GuardedInvocation convertToTypeNoCast(final Class<?> sourceType, final Class<?> targetType) throws Exception { 119 final MethodHandle mh = JavaArgumentConverters.getConverter(targetType); 120 if (mh != null) { 121 return new GuardedInvocation(mh, canLinkTypeStatic(sourceType) ? null : IS_NASHORN_OR_UNDEFINED_TYPE); 122 } 123 124 final GuardedInvocation arrayConverter = getArrayConverter(sourceType, targetType); 125 if(arrayConverter != null) { 126 return arrayConverter; 127 } 128 129 final GuardedInvocation mirrorConverter = getMirrorConverter(sourceType, targetType); 130 if(mirrorConverter != null) { 131 return mirrorConverter; 132 } 133 134 return getSamTypeConverter(sourceType, targetType); 135 } 136 137 /** 138 * Returns a guarded invocation that converts from a source type that is ScriptFunction, or a subclass or a 139 * superclass of it) to a SAM type. 140 * @param sourceType the source type (presumably ScriptFunction or a subclass or a superclass of it) 141 * @param targetType the target type (presumably a SAM type) 142 * @return a guarded invocation that converts from the source type to the target SAM type. null is returned if 143 * either the source type is neither ScriptFunction, nor a subclass, nor a superclass of it, or if the target type 144 * is not a SAM type. 145 * @throws Exception if something goes wrong; generally, if there's an issue with creation of the SAM proxy type 146 * constructor. 147 */ 148 private static GuardedInvocation getSamTypeConverter(final Class<?> sourceType, final Class<?> targetType) throws Exception { 149 // If source type is more generic than ScriptFunction class, we'll need to use a guard 150 final boolean isSourceTypeGeneric = sourceType.isAssignableFrom(ScriptFunction.class); 151 152 if ((isSourceTypeGeneric || ScriptFunction.class.isAssignableFrom(sourceType)) && isAutoConvertibleFromFunction(targetType)) { 153 final MethodHandle ctor = JavaAdapterFactory.getConstructor(ScriptFunction.class, targetType); 154 assert ctor != null; // if isAutoConvertibleFromFunction() returned true, then ctor must exist. 155 return new GuardedInvocation(ctor, isSourceTypeGeneric ? IS_SCRIPT_FUNCTION : null); 156 } 157 return null; 158 } 159 160 /** 161 * Returns a guarded invocation that converts from a source type that is NativeArray to a Java array or List or 162 * Deque type. 163 * @param sourceType the source type (presumably NativeArray a superclass of it) 164 * @param targetType the target type (presumably an array type, or List or Deque) 165 * @return a guarded invocation that converts from the source type to the target type. null is returned if 166 * either the source type is neither NativeArray, nor a superclass of it, or if the target type is not an array 167 * type, List, or Deque. 168 */ 169 private static GuardedInvocation getArrayConverter(final Class<?> sourceType, final Class<?> targetType) { 170 final boolean isSourceTypeNativeArray = sourceType == NativeArray.class; 171 // If source type is more generic than ScriptFunction class, we'll need to use a guard 172 final boolean isSourceTypeGeneric = !isSourceTypeNativeArray && sourceType.isAssignableFrom(NativeArray.class); 173 174 if (isSourceTypeNativeArray || isSourceTypeGeneric) { 175 final MethodHandle guard = isSourceTypeGeneric ? IS_NATIVE_ARRAY : null; 176 if(targetType.isArray()) { 177 return new GuardedInvocation(ARRAY_CONVERTERS.get(targetType), guard); 178 } 179 if(targetType == List.class) { 180 return new GuardedInvocation(JSType.TO_JAVA_LIST.methodHandle(), guard); 181 } 182 if(targetType == Deque.class) { 183 return new GuardedInvocation(JSType.TO_JAVA_DEQUE.methodHandle(), guard); 184 } 185 } 186 return null; 187 } 188 189 private static MethodHandle createArrayConverter(final Class<?> type) { 190 assert type.isArray(); 191 final MethodHandle converter = MH.insertArguments(JSType.TO_JAVA_ARRAY.methodHandle(), 1, type.getComponentType()); 192 return MH.asType(converter, converter.type().changeReturnType(type)); 193 } 194 195 private static GuardedInvocation getMirrorConverter(Class<?> sourceType, Class<?> targetType) { 196 // Could've also used (targetType.isAssignableFrom(ScriptObjectMirror.class) && targetType != Object.class) but 197 // it's probably better to explicitly spell out the supported target types 198 if (targetType == Map.class || targetType == Bindings.class || targetType == JSObject.class || targetType == ScriptObjectMirror.class) { 199 if(ScriptObject.class.isAssignableFrom(sourceType)) { 200 return new GuardedInvocation(CREATE_MIRROR, null); 201 } 202 return new GuardedInvocation(CREATE_MIRROR, IS_SCRIPT_OBJECT); 203 } 204 return null; 205 } 206 207 private static boolean isAutoConvertibleFromFunction(final Class<?> clazz) { 208 return isAbstractClass(clazz) && !ScriptObject.class.isAssignableFrom(clazz) && 209 JavaAdapterFactory.isAutoConvertibleFromFunction(clazz); 210 } 211 212 /** 213 * Utility method used by few other places in the code. Tests if the class has the abstract modifier and is not an 214 * array class. For some reason, array classes have the abstract modifier set in HotSpot JVM, and we don't want to 215 * treat array classes as abstract. 216 * @param clazz the inspected class 217 * @return true if the class is abstract and is not an array type. 218 */ 219 static boolean isAbstractClass(final Class<?> clazz) { 220 return Modifier.isAbstract(clazz.getModifiers()) && !clazz.isArray(); 221 } 222 223 224 @Override 225 public Comparison compareConversion(final Class<?> sourceType, final Class<?> targetType1, final Class<?> targetType2) { 226 if(sourceType == NativeArray.class) { 227 // Prefer lists, as they're less costly to create than arrays. 228 if(isList(targetType1)) { 229 if(!isList(targetType2)) { 230 return Comparison.TYPE_1_BETTER; 231 } 232 } else if(isList(targetType2)) { 233 return Comparison.TYPE_2_BETTER; 234 } 235 // Then prefer arrays 236 if(targetType1.isArray()) { 237 if(!targetType2.isArray()) { 238 return Comparison.TYPE_1_BETTER; 239 } 240 } else if(targetType2.isArray()) { 241 return Comparison.TYPE_2_BETTER; 242 } 243 } 244 if(ScriptObject.class.isAssignableFrom(sourceType)) { 245 // Prefer interfaces 246 if(targetType1.isInterface()) { 247 if(!targetType2.isInterface()) { 248 return Comparison.TYPE_1_BETTER; 249 } 250 } else if(targetType2.isInterface()) { 251 return Comparison.TYPE_2_BETTER; 252 } 253 } 254 return Comparison.INDETERMINATE; 255 } 256 257 private static boolean isList(Class<?> clazz) { 258 return clazz == List.class || clazz == Deque.class; 259 } 260 261 private static final MethodHandle IS_SCRIPT_OBJECT = Guards.isInstance(ScriptObject.class, MH.type(Boolean.TYPE, Object.class)); 262 private static final MethodHandle IS_SCRIPT_FUNCTION = Guards.isInstance(ScriptFunction.class, MH.type(Boolean.TYPE, Object.class)); 263 private static final MethodHandle IS_NATIVE_ARRAY = Guards.isOfClass(NativeArray.class, MH.type(Boolean.TYPE, Object.class)); 264 265 private static final MethodHandle IS_NASHORN_OR_UNDEFINED_TYPE = findOwnMH("isNashornTypeOrUndefined", Boolean.TYPE, Object.class); 266 private static final MethodHandle CREATE_MIRROR = findOwnMH("createMirror", Object.class, Object.class); 267 268 @SuppressWarnings("unused") 269 private static boolean isNashornTypeOrUndefined(final Object obj) { 270 return obj instanceof ScriptObject || obj instanceof Undefined; 271 } 272 273 @SuppressWarnings("unused") 274 private static Object createMirror(final Object obj) { 275 return ScriptUtils.wrap(obj); 276 } 277 278 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 279 return MH.findStatic(MethodHandles.lookup(), NashornLinker.class, name, MH.type(rtype, types)); 280 } 281 } 282 --- EOF ---