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.internal.org.objectweb.asm.Opcodes.ACC_FINAL; 29 import static jdk.internal.org.objectweb.asm.Opcodes.ACC_PRIVATE; 30 import static jdk.internal.org.objectweb.asm.Opcodes.ACC_PUBLIC; 31 import static jdk.internal.org.objectweb.asm.Opcodes.ACC_STATIC; 32 import static jdk.internal.org.objectweb.asm.Opcodes.ACC_SUPER; 33 import static jdk.internal.org.objectweb.asm.Opcodes.ACC_VARARGS; 34 import static jdk.internal.org.objectweb.asm.Opcodes.AALOAD; 35 import static jdk.internal.org.objectweb.asm.Opcodes.ALOAD; 36 import static jdk.internal.org.objectweb.asm.Opcodes.ARRAYLENGTH; 37 import static jdk.internal.org.objectweb.asm.Opcodes.ASTORE; 38 import static jdk.internal.org.objectweb.asm.Opcodes.D2F; 39 import static jdk.internal.org.objectweb.asm.Opcodes.GETSTATIC; 40 import static jdk.internal.org.objectweb.asm.Opcodes.GOTO; 41 import static jdk.internal.org.objectweb.asm.Opcodes.H_INVOKESTATIC; 42 import static jdk.internal.org.objectweb.asm.Opcodes.ICONST_0; 43 import static jdk.internal.org.objectweb.asm.Opcodes.IF_ICMPGE; 44 import static jdk.internal.org.objectweb.asm.Opcodes.ILOAD; 45 import static jdk.internal.org.objectweb.asm.Opcodes.INVOKESPECIAL; 46 import static jdk.internal.org.objectweb.asm.Opcodes.INVOKEVIRTUAL; 47 import static jdk.internal.org.objectweb.asm.Opcodes.ISTORE; 48 import static jdk.internal.org.objectweb.asm.Opcodes.I2B; 49 import static jdk.internal.org.objectweb.asm.Opcodes.I2S; 50 import static jdk.internal.org.objectweb.asm.Opcodes.POP; 51 import static jdk.internal.org.objectweb.asm.Opcodes.PUTSTATIC; 52 import static jdk.internal.org.objectweb.asm.Opcodes.RETURN; 53 import static jdk.nashorn.internal.codegen.CompilerConstants.interfaceCallNoLookup; 54 import static jdk.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup; 55 import static jdk.nashorn.internal.lookup.Lookup.MH; 56 import static jdk.nashorn.internal.runtime.linker.AdaptationResult.Outcome.ERROR_NO_ACCESSIBLE_CONSTRUCTOR; 57 58 import java.lang.invoke.CallSite; 59 import java.lang.invoke.MethodHandle; 60 import java.lang.invoke.MethodHandles.Lookup; 61 import java.lang.invoke.MethodType; 62 import java.lang.reflect.AccessibleObject; 63 import java.lang.reflect.Constructor; 64 import java.lang.reflect.Method; 65 import java.lang.reflect.Modifier; 66 import java.security.AccessControlContext; 67 import java.security.AccessController; 68 import java.security.PrivilegedAction; 69 import java.util.Arrays; 70 import java.util.Collection; 71 import java.util.HashSet; 72 import java.util.Iterator; 73 import java.util.List; 74 import java.util.Set; 75 import jdk.internal.org.objectweb.asm.ClassWriter; 76 import jdk.internal.org.objectweb.asm.FieldVisitor; 77 import jdk.internal.org.objectweb.asm.Handle; 78 import jdk.internal.org.objectweb.asm.Label; 79 import jdk.internal.org.objectweb.asm.MethodVisitor; 80 import jdk.internal.org.objectweb.asm.Opcodes; 81 import jdk.internal.org.objectweb.asm.Type; 82 import jdk.internal.org.objectweb.asm.Handle; 83 import jdk.internal.org.objectweb.asm.Label; 84 import jdk.internal.org.objectweb.asm.Opcodes; 85 import jdk.internal.org.objectweb.asm.Type; 86 import jdk.internal.org.objectweb.asm.commons.InstructionAdapter; 87 import jdk.nashorn.api.scripting.ScriptUtils; 88 import jdk.nashorn.internal.codegen.CompilerConstants.Call; 89 import jdk.nashorn.internal.runtime.Context; 90 import jdk.nashorn.internal.runtime.ScriptFunction; 91 import jdk.nashorn.internal.runtime.ScriptObject; 92 import jdk.nashorn.internal.runtime.linker.AdaptationResult.Outcome; 93 import jdk.internal.reflect.CallerSensitive; 94 95 /** 96 * Generates bytecode for a Java adapter class. Used by the {@link JavaAdapterFactory}. 97 * </p><p> 98 * For every protected or public constructor in the extended class, the adapter class will have either one or two 99 * public constructors (visibility of protected constructors in the extended class is promoted to public). 100 * <li> 101 * <li>For adapter classes with instance-level overrides, a constructor taking a trailing ScriptObject argument preceded 102 * by original constructor arguments is always created on the adapter class. When such a constructor is invoked, the 103 * passed ScriptObject's member functions are used to implement and/or override methods on the original class, 104 * dispatched by name. A single JavaScript function will act as the implementation for all overloaded methods of the 105 * same name. When methods on an adapter instance are invoked, the functions are invoked having the ScriptObject passed 106 * in the instance constructor as their "this". Subsequent changes to the ScriptObject (reassignment or removal of its 107 * functions) will be reflected in the adapter instance as it is live dispatching to its members on every method invocation. 108 * {@code java.lang.Object} methods {@code equals}, {@code hashCode}, and {@code toString} can also be overridden. The 109 * only restriction is that since every JavaScript object already has a {@code toString} function through the 110 * {@code Object.prototype}, the {@code toString} in the adapter is only overridden if the passed ScriptObject has a 111 * {@code toString} function as its own property, and not inherited from a prototype. All other adapter methods can be 112 * implemented or overridden through a prototype-inherited function of the ScriptObject passed to the constructor too. 113 * </li> 114 * <li> 115 * If the original types collectively have only one abstract method, or have several of them, but all share the 116 * same name, an additional constructor for instance-level override adapter is provided for every original constructor; 117 * this one takes a ScriptFunction as its last argument preceded by original constructor arguments. This constructor 118 * will use the passed function as the implementation for all abstract methods. For consistency, any concrete methods 119 * sharing the single abstract method name will also be overridden by the function. When methods on the adapter instance 120 * are invoked, the ScriptFunction is invoked with UNDEFINED or Global as its "this" depending whether the function is 121 * strict or not. 122 * </li> 123 * <li> 124 * If the adapter being generated has class-level overrides, constructors taking same arguments as the superclass 125 * constructors are created. These constructors simply delegate to the superclass constructor. They are simply used to 126 * create instances of the adapter class, with no instance-level overrides, as they don't have them. If the original 127 * class' constructor was variable arity, the adapter constructor will also be variable arity. Protected constructors 128 * are exposed as public. 129 * </li> 130 * </ul> 131 * </p><p> 132 * For adapter methods that return values, all the JavaScript-to-Java conversions supported by Nashorn will be in effect 133 * to coerce the JavaScript function return value to the expected Java return type. 134 * </p><p> 135 * Since we are adding a trailing argument to the generated constructors in the adapter class with instance-level overrides, they will never be 136 * declared as variable arity, even if the original constructor in the superclass was declared as variable arity. The 137 * reason we are passing the additional argument at the end of the argument list instead at the front is that the 138 * source-level script expression <code>new X(a, b) { ... }</code> (which is a proprietary syntax extension Nashorn uses 139 * to resemble Java anonymous classes) is actually equivalent to <code>new X(a, b, { ... })</code>. 140 * </p><p> 141 * It is possible to create two different adapter classes: those that can have class-level overrides, and those that can 142 * have instance-level overrides. When {@link JavaAdapterFactory#getAdapterClassFor(Class[], ScriptObject)} is invoked 143 * with non-null {@code classOverrides} parameter, an adapter class is created that can have class-level overrides, and 144 * the passed script object will be used as the implementations for its methods, just as in the above case of the 145 * constructor taking a script object. Note that in the case of class-level overrides, a new adapter class is created on 146 * every invocation, and the implementation object is bound to the class, not to any instance. All created instances 147 * will share these functions. If it is required to have both class-level overrides and instance-level overrides, the 148 * class-level override adapter class should be subclassed with an instance-override adapter. Since adapters delegate to 149 * super class when an overriding method handle is not specified, this will behave as expected. It is not possible to 150 * have both class-level and instance-level overrides in the same class for security reasons: adapter classes are 151 * defined with a protection domain of their creator code, and an adapter class that has both class and instance level 152 * overrides would need to have two potentially different protection domains: one for class-based behavior and one for 153 * instance-based behavior; since Java classes can only belong to a single protection domain, this could not be 154 * implemented securely. 155 */ 156 final class JavaAdapterBytecodeGenerator { 157 // Field names in adapters 158 private static final String GLOBAL_FIELD_NAME = "global"; 159 private static final String DELEGATE_FIELD_NAME = "delegate"; 160 private static final String IS_FUNCTION_FIELD_NAME = "isFunction"; 161 private static final String CALL_THIS_FIELD_NAME = "callThis"; 162 163 // Initializer names 164 private static final String INIT = "<init>"; 165 private static final String CLASS_INIT = "<clinit>"; 166 167 // Types often used in generated bytecode 168 private static final Type OBJECT_TYPE = Type.getType(Object.class); 169 private static final Type SCRIPT_OBJECT_TYPE = Type.getType(ScriptObject.class); 170 private static final Type SCRIPT_FUNCTION_TYPE = Type.getType(ScriptFunction.class); 171 172 // JavaAdapterServices methods used in generated bytecode 173 private static final Call CHECK_FUNCTION = lookupServiceMethod("checkFunction", ScriptFunction.class, Object.class, String.class); 174 private static final Call EXPORT_RETURN_VALUE = lookupServiceMethod("exportReturnValue", Object.class, Object.class); 175 private static final Call GET_CALL_THIS = lookupServiceMethod("getCallThis", Object.class, ScriptFunction.class, Object.class); 176 private static final Call GET_CLASS_OVERRIDES = lookupServiceMethod("getClassOverrides", ScriptObject.class); 177 private static final Call GET_NON_NULL_GLOBAL = lookupServiceMethod("getNonNullGlobal", ScriptObject.class); 178 private static final Call HAS_OWN_TO_STRING = lookupServiceMethod("hasOwnToString", boolean.class, ScriptObject.class); 179 private static final Call INVOKE_NO_PERMISSIONS = lookupServiceMethod("invokeNoPermissions", void.class, MethodHandle.class, Object.class); 180 private static final Call NOT_AN_OBJECT = lookupServiceMethod("notAnObject", void.class, Object.class); 181 private static final Call SET_GLOBAL = lookupServiceMethod("setGlobal", Runnable.class, ScriptObject.class); 182 private static final Call TO_CHAR_PRIMITIVE = lookupServiceMethod("toCharPrimitive", char.class, Object.class); 183 private static final Call UNSUPPORTED = lookupServiceMethod("unsupported", UnsupportedOperationException.class); 184 private static final Call WRAP_THROWABLE = lookupServiceMethod("wrapThrowable", RuntimeException.class, Throwable.class); 185 186 // Other methods invoked by the generated bytecode 187 private static final Call UNWRAP = staticCallNoLookup(ScriptUtils.class, "unwrap", Object.class, Object.class); 188 private static final Call CHAR_VALUE_OF = staticCallNoLookup(Character.class, "valueOf", Character.class, char.class); 189 private static final Call DOUBLE_VALUE_OF = staticCallNoLookup(Double.class, "valueOf", Double.class, double.class); 190 private static final Call LONG_VALUE_OF = staticCallNoLookup(Long.class, "valueOf", Long.class, long.class); 191 private static final Call RUN = interfaceCallNoLookup(Runnable.class, "run", void.class); 192 193 // ASM handle to the bootstrap method 194 @SuppressWarnings("deprecation") 195 private static final Handle BOOTSTRAP_HANDLE = new Handle(H_INVOKESTATIC, 196 Type.getInternalName(JavaAdapterServices.class), "bootstrap", 197 MethodType.methodType(CallSite.class, Lookup.class, String.class, 198 MethodType.class, int.class).toMethodDescriptorString()); 199 200 // ASM handle to the bootstrap method for array populator 201 @SuppressWarnings("deprecation") 202 private static final Handle CREATE_ARRAY_BOOTSTRAP_HANDLE = new Handle(H_INVOKESTATIC, 203 Type.getInternalName(JavaAdapterServices.class), "createArrayBootstrap", 204 MethodType.methodType(CallSite.class, Lookup.class, String.class, 205 MethodType.class).toMethodDescriptorString()); 206 207 // Field type names used in the generated bytecode 208 private static final String SCRIPT_OBJECT_TYPE_DESCRIPTOR = SCRIPT_OBJECT_TYPE.getDescriptor(); 209 private static final String OBJECT_TYPE_DESCRIPTOR = OBJECT_TYPE.getDescriptor(); 210 private static final String BOOLEAN_TYPE_DESCRIPTOR = Type.BOOLEAN_TYPE.getDescriptor(); 211 212 // Throwable names used in the generated bytecode 213 private static final String RUNTIME_EXCEPTION_TYPE_NAME = Type.getInternalName(RuntimeException.class); 214 private static final String ERROR_TYPE_NAME = Type.getInternalName(Error.class); 215 private static final String THROWABLE_TYPE_NAME = Type.getInternalName(Throwable.class); 216 217 // Some more frequently used method descriptors 218 private static final String GET_METHOD_PROPERTY_METHOD_DESCRIPTOR = Type.getMethodDescriptor(OBJECT_TYPE, SCRIPT_OBJECT_TYPE); 219 private static final String VOID_METHOD_DESCRIPTOR = Type.getMethodDescriptor(Type.VOID_TYPE); 220 221 static final String ADAPTER_PACKAGE_INTERNAL = "jdk/nashorn/javaadapters/"; 222 static final String ADAPTER_PACKAGE = "jdk.nashorn.javaadapters"; 223 private static final int MAX_GENERATED_TYPE_NAME_LENGTH = 255; 224 225 // Method name prefix for invoking super-methods 226 static final String SUPER_PREFIX = "super$"; 227 228 // Method name and type for the no-privilege finalizer delegate 229 private static final String FINALIZER_DELEGATE_NAME = "$$nashornFinalizerDelegate"; 230 private static final String FINALIZER_DELEGATE_METHOD_DESCRIPTOR = Type.getMethodDescriptor(Type.VOID_TYPE, OBJECT_TYPE); 231 232 /** 233 * Collection of methods we never override: Object.clone(), Object.finalize(). 234 */ 235 private static final Collection<MethodInfo> EXCLUDED = getExcludedMethods(); 236 237 // This is the superclass for our generated adapter. 238 private final Class<?> superClass; 239 // Interfaces implemented by our generated adapter. 240 private final List<Class<?>> interfaces; 241 // Class loader used as the parent for the class loader we'll create to load the generated class. It will be a class 242 // loader that has the visibility of all original types (class to extend and interfaces to implement) and of the 243 // Nashorn classes. 244 private final ClassLoader commonLoader; 245 // Is this a generator for the version of the class that can have overrides on the class level? 246 private final boolean classOverride; 247 // Binary name of the superClass 248 private final String superClassName; 249 // Binary name of the generated class. 250 private final String generatedClassName; 251 private final Set<String> abstractMethodNames = new HashSet<>(); 252 private final String samName; 253 private final Set<MethodInfo> finalMethods = new HashSet<>(EXCLUDED); 254 private final Set<MethodInfo> methodInfos = new HashSet<>(); 255 private final boolean autoConvertibleFromFunction; 256 private boolean hasExplicitFinalizer = false; 257 258 private final ClassWriter cw; 259 260 /** 261 * Creates a generator for the bytecode for the adapter for the specified superclass and interfaces. 262 * @param superClass the superclass the adapter will extend. 263 * @param interfaces the interfaces the adapter will implement. 264 * @param commonLoader the class loader that can see all of superClass, interfaces, and Nashorn classes. 265 * @param classOverride true to generate the bytecode for the adapter that has class-level overrides, false to 266 * generate the bytecode for the adapter that has instance-level overrides. 267 * @throws AdaptationException if the adapter can not be generated for some reason. 268 */ 269 JavaAdapterBytecodeGenerator(final Class<?> superClass, final List<Class<?>> interfaces, 270 final ClassLoader commonLoader, final boolean classOverride) throws AdaptationException { 271 assert superClass != null && !superClass.isInterface(); 272 assert interfaces != null; 273 274 this.superClass = superClass; 275 this.interfaces = interfaces; 276 this.classOverride = classOverride; 277 this.commonLoader = commonLoader; 278 cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS) { 279 @Override 280 protected String getCommonSuperClass(final String type1, final String type2) { 281 // We need to override ClassWriter.getCommonSuperClass to use this factory's commonLoader as a class 282 // loader to find the common superclass of two types when needed. 283 return JavaAdapterBytecodeGenerator.this.getCommonSuperClass(type1, type2); 284 } 285 }; 286 superClassName = Type.getInternalName(superClass); 287 generatedClassName = getGeneratedClassName(superClass, interfaces); 288 289 cw.visit(Opcodes.V1_7, ACC_PUBLIC | ACC_SUPER, generatedClassName, null, superClassName, getInternalTypeNames(interfaces)); 290 generateField(GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 291 generateField(DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 292 293 gatherMethods(superClass); 294 gatherMethods(interfaces); 295 if (abstractMethodNames.size() == 1) { 296 samName = abstractMethodNames.iterator().next(); 297 generateField(CALL_THIS_FIELD_NAME, OBJECT_TYPE_DESCRIPTOR); 298 generateField(IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR); 299 } else { 300 samName = null; 301 } 302 if(classOverride) { 303 generateClassInit(); 304 } 305 autoConvertibleFromFunction = generateConstructors(); 306 generateMethods(); 307 generateSuperMethods(); 308 if (hasExplicitFinalizer) { 309 generateFinalizerMethods(); 310 } 311 // } 312 cw.visitEnd(); 313 } 314 315 private void generateField(final String name, final String fieldDesc) { 316 cw.visitField(ACC_PRIVATE | ACC_FINAL | (classOverride ? ACC_STATIC : 0), name, fieldDesc, null, null).visitEnd(); 317 } 318 319 JavaAdapterClassLoader createAdapterClassLoader() { 320 return new JavaAdapterClassLoader(generatedClassName, cw.toByteArray()); 321 } 322 323 boolean isAutoConvertibleFromFunction() { 324 return autoConvertibleFromFunction; 325 } 326 327 private static String getGeneratedClassName(final Class<?> superType, final List<Class<?>> interfaces) { 328 // The class we use to primarily name our adapter is either the superclass, or if it is Object (meaning we're 329 // just implementing interfaces or extending Object), then the first implemented interface or Object. 330 final Class<?> namingType = superType == Object.class ? (interfaces.isEmpty()? Object.class : interfaces.get(0)) : superType; 331 final Package pkg = namingType.getPackage(); 332 final String namingTypeName = Type.getInternalName(namingType); 333 final StringBuilder buf = new StringBuilder(); 334 buf.append(ADAPTER_PACKAGE_INTERNAL).append(namingTypeName.replace('/', '_')); 335 final Iterator<Class<?>> it = interfaces.iterator(); 336 if(superType == Object.class && it.hasNext()) { 337 it.next(); // Skip first interface, it was used to primarily name the adapter 338 } 339 // Append interface names to the adapter name 340 while(it.hasNext()) { 341 buf.append("$$").append(it.next().getSimpleName()); 342 } 343 return buf.toString().substring(0, Math.min(MAX_GENERATED_TYPE_NAME_LENGTH, buf.length())); 344 } 345 346 /** 347 * Given a list of class objects, return an array with their binary names. Used to generate the array of interface 348 * names to implement. 349 * @param classes the classes 350 * @return an array of names 351 */ 352 private static String[] getInternalTypeNames(final List<Class<?>> classes) { 353 final int interfaceCount = classes.size(); 354 final String[] interfaceNames = new String[interfaceCount]; 355 for(int i = 0; i < interfaceCount; ++i) { 356 interfaceNames[i] = Type.getInternalName(classes.get(i)); 357 } 358 return interfaceNames; 359 } 360 361 private void generateClassInit() { 362 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_STATIC, CLASS_INIT, 363 VOID_METHOD_DESCRIPTOR, null, null)); 364 365 // Assign "global = Context.getGlobal()" 366 GET_NON_NULL_GLOBAL.invoke(mv); 367 mv.putstatic(generatedClassName, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 368 369 GET_CLASS_OVERRIDES.invoke(mv); 370 if(samName != null) { 371 // If the class is a SAM, allow having ScriptFunction passed as class overrides 372 mv.dup(); 373 mv.instanceOf(SCRIPT_FUNCTION_TYPE); 374 mv.dup(); 375 mv.putstatic(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR); 376 final Label notFunction = new Label(); 377 mv.ifeq(notFunction); 378 mv.dup(); 379 mv.checkcast(SCRIPT_FUNCTION_TYPE); 380 emitInitCallThis(mv); 381 mv.visitLabel(notFunction); 382 } 383 mv.putstatic(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 384 385 endInitMethod(mv); 386 } 387 388 /** 389 * Emit bytecode for initializing the "callThis" field. 390 */ 391 private void emitInitCallThis(final InstructionAdapter mv) { 392 loadField(mv, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 393 GET_CALL_THIS.invoke(mv); 394 if(classOverride) { 395 mv.putstatic(generatedClassName, CALL_THIS_FIELD_NAME, OBJECT_TYPE_DESCRIPTOR); 396 } else { 397 // It is presumed ALOAD 0 was already executed 398 mv.putfield(generatedClassName, CALL_THIS_FIELD_NAME, OBJECT_TYPE_DESCRIPTOR); 399 } 400 } 401 402 private boolean generateConstructors() throws AdaptationException { 403 boolean gotCtor = false; 404 boolean canBeAutoConverted = false; 405 for (final Constructor<?> ctor: superClass.getDeclaredConstructors()) { 406 final int modifier = ctor.getModifiers(); 407 if((modifier & (Modifier.PUBLIC | Modifier.PROTECTED)) != 0 && !isCallerSensitive(ctor)) { 408 canBeAutoConverted = generateConstructors(ctor) | canBeAutoConverted; 409 gotCtor = true; 410 } 411 } 412 if(!gotCtor) { 413 throw new AdaptationException(ERROR_NO_ACCESSIBLE_CONSTRUCTOR, superClass.getCanonicalName()); 414 } 415 return canBeAutoConverted; 416 } 417 418 private boolean generateConstructors(final Constructor<?> ctor) { 419 if(classOverride) { 420 // Generate a constructor that just delegates to ctor. This is used with class-level overrides, when we want 421 // to create instances without further per-instance overrides. 422 generateDelegatingConstructor(ctor); 423 return false; 424 } 425 426 // Generate a constructor that delegates to ctor, but takes an additional ScriptObject parameter at the 427 // beginning of its parameter list. 428 generateOverridingConstructor(ctor, false); 429 430 if (samName == null) { 431 return false; 432 } 433 // If all our abstract methods have a single name, generate an additional constructor, one that takes a 434 // ScriptFunction as its first parameter and assigns it as the implementation for all abstract methods. 435 generateOverridingConstructor(ctor, true); 436 // If the original type only has a single abstract method name, as well as a default ctor, then it can 437 // be automatically converted from JS function. 438 return ctor.getParameterTypes().length == 0; 439 } 440 441 private void generateDelegatingConstructor(final Constructor<?> ctor) { 442 final Type originalCtorType = Type.getType(ctor); 443 final Type[] argTypes = originalCtorType.getArgumentTypes(); 444 445 // All constructors must be public, even if in the superclass they were protected. 446 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC | 447 (ctor.isVarArgs() ? ACC_VARARGS : 0), INIT, 448 Type.getMethodDescriptor(originalCtorType.getReturnType(), argTypes), null, null)); 449 450 mv.visitCode(); 451 emitSuperConstructorCall(mv, originalCtorType.getDescriptor()); 452 453 endInitMethod(mv); 454 } 455 456 /** 457 * Generates a constructor for the instance adapter class. This constructor will take the same arguments as the supertype 458 * constructor passed as the argument here, and delegate to it. However, it will take an additional argument of 459 * either ScriptObject or ScriptFunction type (based on the value of the "fromFunction" parameter), and initialize 460 * all the method handle fields of the adapter instance with functions from the script object (or the script 461 * function itself, if that's what's passed). There is one method handle field in the adapter class for every method 462 * that can be implemented or overridden; the name of every field is same as the name of the method, with a number 463 * suffix that makes it unique in case of overloaded methods. The generated constructor will invoke 464 * {@link #getHandle(ScriptFunction, MethodType, boolean)} or {@link #getHandle(Object, String, MethodType, 465 * boolean)} to obtain the method handles; these methods make sure to add the necessary conversions and arity 466 * adjustments so that the resulting method handles can be invoked from generated methods using {@code invokeExact}. 467 * The constructor that takes a script function will only initialize the methods with the same name as the single 468 * abstract method. The constructor will also store the Nashorn global that was current at the constructor 469 * invocation time in a field named "global". The generated constructor will be public, regardless of whether the 470 * supertype constructor was public or protected. The generated constructor will not be variable arity, even if the 471 * supertype constructor was. 472 * @param ctor the supertype constructor that is serving as the base for the generated constructor. 473 * @param fromFunction true if we're generating a constructor that initializes SAM types from a single 474 * ScriptFunction passed to it, false if we're generating a constructor that initializes an arbitrary type from a 475 * ScriptObject passed to it. 476 */ 477 private void generateOverridingConstructor(final Constructor<?> ctor, final boolean fromFunction) { 478 final Type originalCtorType = Type.getType(ctor); 479 final Type[] originalArgTypes = originalCtorType.getArgumentTypes(); 480 final int argLen = originalArgTypes.length; 481 final Type[] newArgTypes = new Type[argLen + 1]; 482 483 // Insert ScriptFunction|ScriptObject as the last argument to the constructor 484 final Type extraArgumentType = fromFunction ? SCRIPT_FUNCTION_TYPE : SCRIPT_OBJECT_TYPE; 485 newArgTypes[argLen] = extraArgumentType; 486 System.arraycopy(originalArgTypes, 0, newArgTypes, 0, argLen); 487 488 // All constructors must be public, even if in the superclass they were protected. 489 // Existing super constructor <init>(this, args...) triggers generating <init>(this, args..., delegate). 490 // Any variable arity constructors become fixed-arity with explicit array arguments. 491 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, INIT, 492 Type.getMethodDescriptor(originalCtorType.getReturnType(), newArgTypes), null, null)); 493 494 mv.visitCode(); 495 // First, invoke super constructor with original arguments. 496 final int extraArgOffset = emitSuperConstructorCall(mv, originalCtorType.getDescriptor()); 497 498 // Assign "this.global = Context.getGlobal()" 499 mv.visitVarInsn(ALOAD, 0); 500 GET_NON_NULL_GLOBAL.invoke(mv); 501 mv.putfield(generatedClassName, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 502 503 // Assign "this.delegate = delegate" 504 mv.visitVarInsn(ALOAD, 0); 505 mv.visitVarInsn(ALOAD, extraArgOffset); 506 mv.putfield(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 507 508 if (fromFunction) { 509 // Assign "isFunction = true" 510 mv.visitVarInsn(ALOAD, 0); 511 mv.iconst(1); 512 mv.putfield(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR); 513 514 mv.visitVarInsn(ALOAD, 0); 515 mv.visitVarInsn(ALOAD, extraArgOffset); 516 emitInitCallThis(mv); 517 } 518 519 endInitMethod(mv); 520 521 if (! fromFunction) { 522 newArgTypes[argLen] = OBJECT_TYPE; 523 final InstructionAdapter mv2 = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, INIT, 524 Type.getMethodDescriptor(originalCtorType.getReturnType(), newArgTypes), null, null)); 525 generateOverridingConstructorWithObjectParam(mv2, originalCtorType.getDescriptor()); 526 } 527 } 528 529 // Object additional param accepting constructor - generated to handle null and undefined value 530 // for script adapters. This is effectively to throw TypeError on such script adapters. See 531 // JavaAdapterServices.getHandle as well. 532 private void generateOverridingConstructorWithObjectParam(final InstructionAdapter mv, final String ctorDescriptor) { 533 mv.visitCode(); 534 final int extraArgOffset = emitSuperConstructorCall(mv, ctorDescriptor); 535 mv.visitVarInsn(ALOAD, extraArgOffset); 536 NOT_AN_OBJECT.invoke(mv); 537 endInitMethod(mv); 538 } 539 540 private static void endInitMethod(final InstructionAdapter mv) { 541 mv.visitInsn(RETURN); 542 endMethod(mv); 543 } 544 545 private static void endMethod(final InstructionAdapter mv) { 546 mv.visitMaxs(0, 0); 547 mv.visitEnd(); 548 } 549 550 /** 551 * Encapsulation of the information used to generate methods in the adapter classes. Basically, a wrapper around the 552 * reflective Method object, a cached MethodType, and the name of the field in the adapter class that will hold the 553 * method handle serving as the implementation of this method in adapter instances. 554 * 555 */ 556 private static class MethodInfo { 557 private final Method method; 558 private final MethodType type; 559 560 private MethodInfo(final Class<?> clazz, final String name, final Class<?>... argTypes) throws NoSuchMethodException { 561 this(clazz.getDeclaredMethod(name, argTypes)); 562 } 563 564 private MethodInfo(final Method method) { 565 this.method = method; 566 this.type = MH.type(method.getReturnType(), method.getParameterTypes()); 567 } 568 569 @Override 570 public boolean equals(final Object obj) { 571 return obj instanceof MethodInfo && equals((MethodInfo)obj); 572 } 573 574 private boolean equals(final MethodInfo other) { 575 // Only method name and type are used for comparison; method handle field name is not. 576 return getName().equals(other.getName()) && type.equals(other.type); 577 } 578 579 String getName() { 580 return method.getName(); 581 } 582 583 @Override 584 public int hashCode() { 585 return getName().hashCode() ^ type.hashCode(); 586 } 587 } 588 589 private void generateMethods() { 590 for(final MethodInfo mi: methodInfos) { 591 generateMethod(mi); 592 } 593 } 594 595 /** 596 * Generates a method in the adapter class that adapts a method from the 597 * original class. The generated method will either invoke the delegate 598 * using a CALL dynamic operation call site (if it is a SAM method and the 599 * delegate is a ScriptFunction), or invoke GET_METHOD_PROPERTY dynamic 600 * operation with the method name as the argument and then invoke the 601 * returned ScriptFunction using the CALL dynamic operation. If 602 * GET_METHOD_PROPERTY returns null or undefined (that is, the JS object 603 * doesn't provide an implementation for the method) then the method will 604 * either do a super invocation to base class, or if the method is abstract, 605 * throw an {@link UnsupportedOperationException}. Finally, if 606 * GET_METHOD_PROPERTY returns something other than a ScriptFunction, null, 607 * or undefined, a TypeError is thrown. The current Global is checked before 608 * the dynamic operations, and if it is different than the Global used to 609 * create the adapter, the creating Global is set to be the current Global. 610 * In this case, the previously current Global is restored after the 611 * invocation. If CALL results in a Throwable that is not one of the 612 * method's declared exceptions, and is not an unchecked throwable, then it 613 * is wrapped into a {@link RuntimeException} and the runtime exception is 614 * thrown. 615 * @param mi the method info describing the method to be generated. 616 */ 617 private void generateMethod(final MethodInfo mi) { 618 final Method method = mi.method; 619 final Class<?>[] exceptions = method.getExceptionTypes(); 620 final String[] exceptionNames = getExceptionNames(exceptions); 621 final MethodType type = mi.type; 622 final String methodDesc = type.toMethodDescriptorString(); 623 final String name = mi.getName(); 624 625 final Type asmType = Type.getMethodType(methodDesc); 626 final Type[] asmArgTypes = asmType.getArgumentTypes(); 627 628 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(getAccessModifiers(method), name, 629 methodDesc, null, exceptionNames)); 630 mv.visitCode(); 631 632 final Class<?> returnType = type.returnType(); 633 final Type asmReturnType = Type.getType(returnType); 634 635 // Determine the first index for a local variable 636 int nextLocalVar = 1; // "this" is at 0 637 for(final Type t: asmArgTypes) { 638 nextLocalVar += t.getSize(); 639 } 640 // Set our local variable index 641 final int globalRestoringRunnableVar = nextLocalVar++; 642 643 // Load the creatingGlobal object 644 loadField(mv, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 645 646 // stack: [creatingGlobal] 647 SET_GLOBAL.invoke(mv); 648 // stack: [runnable] 649 mv.visitVarInsn(ASTORE, globalRestoringRunnableVar); 650 // stack: [] 651 652 final Label tryBlockStart = new Label(); 653 mv.visitLabel(tryBlockStart); 654 655 final Label callCallee = new Label(); 656 final Label defaultBehavior = new Label(); 657 // If this is a SAM type... 658 if (samName != null) { 659 // ...every method will be checking whether we're initialized with a 660 // function. 661 loadField(mv, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR); 662 // stack: [isFunction] 663 if (name.equals(samName)) { 664 final Label notFunction = new Label(); 665 mv.ifeq(notFunction); 666 // stack: [] 667 // If it's a SAM method, it'll load delegate as the "callee" and 668 // "callThis" as "this" for the call if delegate is a function. 669 loadField(mv, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 670 // NOTE: if we added "mv.checkcast(SCRIPT_FUNCTION_TYPE);" here 671 // we could emit the invokedynamic CALL instruction with signature 672 // (ScriptFunction, Object, ...) instead of (Object, Object, ...). 673 // We could combine this with an optimization in 674 // ScriptFunction.findCallMethod where it could link a call with a 675 // thinner guard when the call site statically guarantees that the 676 // callee argument is a ScriptFunction. Additionally, we could use 677 // a "ScriptFunction function" field in generated classes instead 678 // of a "boolean isFunction" field to avoid the checkcast. 679 loadField(mv, CALL_THIS_FIELD_NAME, OBJECT_TYPE_DESCRIPTOR); 680 // stack: [callThis, delegate] 681 mv.goTo(callCallee); 682 mv.visitLabel(notFunction); 683 } else { 684 // If it's not a SAM method, and the delegate is a function, 685 // it'll fall back to default behavior 686 mv.ifne(defaultBehavior); 687 // stack: [] 688 } 689 } 690 691 // At this point, this is either not a SAM method or the delegate is 692 // not a ScriptFunction. We need to emit a GET_METHOD_PROPERTY Nashorn 693 // invokedynamic. 694 695 if(name.equals("toString")) { 696 // Since every JS Object has a toString, we only override 697 // "String toString()" it if it's explicitly specified on the object. 698 loadField(mv, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 699 // stack: [delegate] 700 HAS_OWN_TO_STRING.invoke(mv); 701 // stack: [hasOwnToString] 702 mv.ifeq(defaultBehavior); 703 } 704 705 loadField(mv, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR); 706 mv.dup(); 707 // stack: [delegate, delegate] 708 final String encodedName = NameCodec.encode(name); 709 mv.visitInvokeDynamicInsn(encodedName, 710 GET_METHOD_PROPERTY_METHOD_DESCRIPTOR, BOOTSTRAP_HANDLE, 711 NashornCallSiteDescriptor.GET_METHOD_PROPERTY); 712 // stack: [callee, delegate] 713 mv.visitLdcInsn(name); 714 // stack: [name, callee, delegate] 715 CHECK_FUNCTION.invoke(mv); 716 // stack: [fnCalleeOrNull, delegate] 717 final Label hasFunction = new Label(); 718 mv.dup(); 719 // stack: [fnCalleeOrNull, fnCalleeOrNull, delegate] 720 mv.ifnonnull(hasFunction); 721 // stack: [null, delegate] 722 // If it's null or undefined, clear stack and fall back to default 723 // behavior. 724 mv.pop2(); 725 // stack: [] 726 727 // We can also arrive here from check for "delegate instanceof ScriptFunction" 728 // in a non-SAM method as well as from a check for "hasOwnToString(delegate)" 729 // for a toString delegate. 730 mv.visitLabel(defaultBehavior); 731 final Runnable emitFinally = ()->emitFinally(mv, globalRestoringRunnableVar); 732 final Label normalFinally = new Label(); 733 if(Modifier.isAbstract(method.getModifiers())) { 734 // If the super method is abstract, throw UnsupportedOperationException 735 UNSUPPORTED.invoke(mv); 736 // NOTE: no need to invoke emitFinally.run() as we're inside the 737 // tryBlockStart/tryBlockEnd range, so throwing this exception will 738 // transfer control to the rethrow handler and the finally block in it 739 // will execute. 740 mv.athrow(); 741 } else { 742 // If the super method is not abstract, delegate to it. 743 emitSuperCall(mv, method.getDeclaringClass(), name, methodDesc); 744 mv.goTo(normalFinally); 745 } 746 747 mv.visitLabel(hasFunction); 748 // stack: [callee, delegate] 749 mv.swap(); 750 // stack [delegate, callee] 751 mv.visitLabel(callCallee); 752 753 754 // Load all parameters back on stack for dynamic invocation. 755 756 int varOffset = 1; 757 // If the param list length is more than 253 slots, we can't invoke it 758 // directly as with (callee, this) it'll exceed 255. 759 final boolean isVarArgCall = getParamListLengthInSlots(asmArgTypes) > 253; 760 for (final Type t : asmArgTypes) { 761 mv.load(varOffset, t); 762 convertParam(mv, t, isVarArgCall); 763 varOffset += t.getSize(); 764 } 765 // stack: [args..., callee, delegate] 766 767 // If the resulting parameter list length is too long... 768 if (isVarArgCall) { 769 // ... we pack the parameters (except callee and this) into an array 770 // and use Nashorn vararg invocation. 771 mv.visitInvokeDynamicInsn(NameCodec.EMPTY_NAME, 772 getArrayCreatorMethodType(type).toMethodDescriptorString(), 773 CREATE_ARRAY_BOOTSTRAP_HANDLE); 774 } 775 776 // Invoke the target method handle 777 mv.visitInvokeDynamicInsn(encodedName, 778 getCallMethodType(isVarArgCall, type).toMethodDescriptorString(), 779 BOOTSTRAP_HANDLE, NashornCallSiteDescriptor.CALL); 780 // stack: [returnValue] 781 convertReturnValue(mv, returnType); 782 mv.visitLabel(normalFinally); 783 emitFinally.run(); 784 mv.areturn(asmReturnType); 785 786 // If Throwable is not declared, we need an adapter from Throwable to RuntimeException 787 final boolean throwableDeclared = isThrowableDeclared(exceptions); 788 final Label throwableHandler; 789 if (!throwableDeclared) { 790 // Add "throw new RuntimeException(Throwable)" handler for Throwable 791 throwableHandler = new Label(); 792 mv.visitLabel(throwableHandler); 793 WRAP_THROWABLE.invoke(mv); 794 // Fall through to rethrow handler 795 } else { 796 throwableHandler = null; 797 } 798 final Label rethrowHandler = new Label(); 799 mv.visitLabel(rethrowHandler); 800 // Rethrow handler for RuntimeException, Error, and all declared exception types 801 emitFinally.run(); 802 mv.athrow(); 803 804 if(throwableDeclared) { 805 mv.visitTryCatchBlock(tryBlockStart, normalFinally, rethrowHandler, THROWABLE_TYPE_NAME); 806 assert throwableHandler == null; 807 } else { 808 mv.visitTryCatchBlock(tryBlockStart, normalFinally, rethrowHandler, RUNTIME_EXCEPTION_TYPE_NAME); 809 mv.visitTryCatchBlock(tryBlockStart, normalFinally, rethrowHandler, ERROR_TYPE_NAME); 810 for(final String excName: exceptionNames) { 811 mv.visitTryCatchBlock(tryBlockStart, normalFinally, rethrowHandler, excName); 812 } 813 mv.visitTryCatchBlock(tryBlockStart, normalFinally, throwableHandler, THROWABLE_TYPE_NAME); 814 } 815 endMethod(mv); 816 } 817 818 private static MethodType getCallMethodType(final boolean isVarArgCall, final MethodType type) { 819 final Class<?>[] callParamTypes; 820 if (isVarArgCall) { 821 // Variable arity calls are always (Object callee, Object this, Object[] params) 822 callParamTypes = new Class<?>[] { Object.class, Object.class, Object[].class }; 823 } else { 824 // Adjust invocation type signature for conversions we instituted in 825 // convertParam; also, byte and short get passed as ints. 826 final Class<?>[] origParamTypes = type.parameterArray(); 827 callParamTypes = new Class<?>[origParamTypes.length + 2]; 828 callParamTypes[0] = Object.class; // callee; could be ScriptFunction.class ostensibly 829 callParamTypes[1] = Object.class; // this 830 for(int i = 0; i < origParamTypes.length; ++i) { 831 callParamTypes[i + 2] = getNashornParamType(origParamTypes[i], false); 832 } 833 } 834 return MethodType.methodType(getNashornReturnType(type.returnType()), callParamTypes); 835 } 836 837 private static MethodType getArrayCreatorMethodType(final MethodType type) { 838 final Class<?>[] callParamTypes = type.parameterArray(); 839 for(int i = 0; i < callParamTypes.length; ++i) { 840 callParamTypes[i] = getNashornParamType(callParamTypes[i], true); 841 } 842 return MethodType.methodType(Object[].class, callParamTypes); 843 } 844 845 private static Class<?> getNashornParamType(final Class<?> clazz, final boolean varArg) { 846 if (clazz == byte.class || clazz == short.class) { 847 return int.class; 848 } else if (clazz == float.class) { 849 // If using variable arity, we'll pass a Double instead of double 850 // so that floats don't extend the length of the parameter list. 851 // We return Object.class instead of Double.class though as the 852 // array collector will anyway operate on Object. 853 return varArg ? Object.class : double.class; 854 } else if (!clazz.isPrimitive() || clazz == long.class || clazz == char.class) { 855 return Object.class; 856 } 857 return clazz; 858 } 859 860 private static Class<?> getNashornReturnType(final Class<?> clazz) { 861 if (clazz == byte.class || clazz == short.class) { 862 return int.class; 863 } else if (clazz == float.class) { 864 return double.class; 865 } else if (clazz == void.class || clazz == char.class) { 866 return Object.class; 867 } 868 return clazz; 869 } 870 871 872 private void loadField(final InstructionAdapter mv, final String name, final String desc) { 873 if(classOverride) { 874 mv.getstatic(generatedClassName, name, desc); 875 } else { 876 mv.visitVarInsn(ALOAD, 0); 877 mv.getfield(generatedClassName, name, desc); 878 } 879 } 880 881 private static void convertReturnValue(final InstructionAdapter mv, final Class<?> origReturnType) { 882 if (origReturnType == void.class) { 883 mv.pop(); 884 } else if (origReturnType == Object.class) { 885 // Must hide ConsString (and potentially other internal Nashorn types) from callers 886 EXPORT_RETURN_VALUE.invoke(mv); 887 } else if (origReturnType == byte.class) { 888 mv.visitInsn(I2B); 889 } else if (origReturnType == short.class) { 890 mv.visitInsn(I2S); 891 } else if (origReturnType == float.class) { 892 mv.visitInsn(D2F); 893 } else if (origReturnType == char.class) { 894 TO_CHAR_PRIMITIVE.invoke(mv); 895 } 896 } 897 898 /** 899 * Emits instruction for converting a parameter on the top of the stack to 900 * a type that is understood by Nashorn. 901 * @param mv the current method visitor 902 * @param t the type on the top of the stack 903 * @param varArg if the invocation will be variable arity 904 */ 905 private static void convertParam(final InstructionAdapter mv, final Type t, final boolean varArg) { 906 // We perform conversions of some primitives to accommodate types that 907 // Nashorn can handle. 908 switch(t.getSort()) { 909 case Type.CHAR: 910 // Chars are boxed, as we don't know if the JS code wants to treat 911 // them as an effective "unsigned short" or as a single-char string. 912 CHAR_VALUE_OF.invoke(mv); 913 break; 914 case Type.FLOAT: 915 // Floats are widened to double. 916 mv.visitInsn(Opcodes.F2D); 917 if (varArg) { 918 // We'll be boxing everything anyway for the vararg invocation, 919 // so we might as well do it proactively here and thus not cause 920 // a widening in the number of slots, as that could even make 921 // the array creation invocation go over 255 param slots. 922 DOUBLE_VALUE_OF.invoke(mv); 923 } 924 break; 925 case Type.LONG: 926 // Longs are boxed as Nashorn can't represent them precisely as a 927 // primitive number. 928 LONG_VALUE_OF.invoke(mv); 929 break; 930 case Type.OBJECT: 931 if(t.equals(OBJECT_TYPE)) { 932 // Object can carry a ScriptObjectMirror and needs to be unwrapped 933 // before passing into a Nashorn function. 934 UNWRAP.invoke(mv); 935 } 936 break; 937 } 938 } 939 940 private static int getParamListLengthInSlots(final Type[] paramTypes) { 941 int len = paramTypes.length; 942 for(final Type t: paramTypes) { 943 final int sort = t.getSort(); 944 if (sort == Type.FLOAT || sort == Type.DOUBLE) { 945 // Floats are widened to double, so they'll take up two slots. 946 // Longs on the other hand are always boxed, so their width 947 // becomes 1 and thus they don't contribute an extra slot here. 948 ++len; 949 } 950 } 951 return len; 952 } 953 /** 954 * Emit code to restore the previous Nashorn Context when needed. 955 * @param mv the instruction adapter 956 * @param globalRestoringRunnableVar index of the local variable holding the reference to the global restoring Runnable 957 */ 958 private static void emitFinally(final InstructionAdapter mv, final int globalRestoringRunnableVar) { 959 mv.visitVarInsn(ALOAD, globalRestoringRunnableVar); 960 RUN.invoke(mv); 961 } 962 963 private static boolean isThrowableDeclared(final Class<?>[] exceptions) { 964 for (final Class<?> exception : exceptions) { 965 if (exception == Throwable.class) { 966 return true; 967 } 968 } 969 return false; 970 } 971 972 private void generateSuperMethods() { 973 for(final MethodInfo mi: methodInfos) { 974 if(!Modifier.isAbstract(mi.method.getModifiers())) { 975 generateSuperMethod(mi); 976 } 977 } 978 } 979 980 private void generateSuperMethod(final MethodInfo mi) { 981 final Method method = mi.method; 982 983 final String methodDesc = mi.type.toMethodDescriptorString(); 984 final String name = mi.getName(); 985 986 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(getAccessModifiers(method), 987 SUPER_PREFIX + name, methodDesc, null, getExceptionNames(method.getExceptionTypes()))); 988 mv.visitCode(); 989 990 emitSuperCall(mv, method.getDeclaringClass(), name, methodDesc); 991 mv.areturn(Type.getType(mi.type.returnType())); 992 endMethod(mv); 993 } 994 995 // find the appropriate super type to use for invokespecial on the given interface 996 private Class<?> findInvokespecialOwnerFor(final Class<?> cl) { 997 assert Modifier.isInterface(cl.getModifiers()) : cl + " is not an interface"; 998 999 if (cl.isAssignableFrom(superClass)) { 1000 return superClass; 1001 } 1002 1003 for (final Class<?> iface : interfaces) { 1004 if (cl.isAssignableFrom(iface)) { 1005 return iface; 1006 } 1007 } 1008 1009 // we better that interface that extends the given interface! 1010 throw new AssertionError("can't find the class/interface that extends " + cl); 1011 } 1012 1013 private int emitSuperConstructorCall(final InstructionAdapter mv, final String methodDesc) { 1014 return emitSuperCall(mv, null, INIT, methodDesc, true); 1015 } 1016 1017 private int emitSuperCall(final InstructionAdapter mv, final Class<?> owner, final String name, final String methodDesc) { 1018 return emitSuperCall(mv, owner, name, methodDesc, false); 1019 } 1020 1021 private int emitSuperCall(final InstructionAdapter mv, final Class<?> owner, final String name, final String methodDesc, final boolean constructor) { 1022 mv.visitVarInsn(ALOAD, 0); 1023 int nextParam = 1; 1024 final Type methodType = Type.getMethodType(methodDesc); 1025 for(final Type t: methodType.getArgumentTypes()) { 1026 mv.load(nextParam, t); 1027 nextParam += t.getSize(); 1028 } 1029 1030 // default method - non-abstract, interface method 1031 if (!constructor && Modifier.isInterface(owner.getModifiers())) { 1032 // we should call default method on the immediate "super" type - not on (possibly) 1033 // the indirectly inherited interface class! 1034 mv.invokespecial(Type.getInternalName(findInvokespecialOwnerFor(owner)), name, methodDesc, false); 1035 } else { 1036 mv.invokespecial(superClassName, name, methodDesc, false); 1037 } 1038 return nextParam; 1039 } 1040 1041 private void generateFinalizerMethods() { 1042 generateFinalizerDelegate(); 1043 generateFinalizerOverride(); 1044 } 1045 1046 private void generateFinalizerDelegate() { 1047 // Generate a delegate that will be invoked from the no-permission trampoline. Note it can be private, as we'll 1048 // refer to it with a MethodHandle constant pool entry in the overridden finalize() method (see 1049 // generateFinalizerOverride()). 1050 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PRIVATE | ACC_STATIC, 1051 FINALIZER_DELEGATE_NAME, FINALIZER_DELEGATE_METHOD_DESCRIPTOR, null, null)); 1052 1053 // Simply invoke super.finalize() 1054 mv.visitVarInsn(ALOAD, 0); 1055 mv.checkcast(Type.getType(generatedClassName)); 1056 mv.invokespecial(superClassName, "finalize", VOID_METHOD_DESCRIPTOR, false); 1057 1058 mv.visitInsn(RETURN); 1059 endMethod(mv); 1060 } 1061 1062 @SuppressWarnings("deprecation") 1063 private void generateFinalizerOverride() { 1064 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, "finalize", 1065 VOID_METHOD_DESCRIPTOR, null, null)); 1066 // Overridden finalizer will take a MethodHandle to the finalizer delegating method, ... 1067 mv.aconst(new Handle(Opcodes.H_INVOKESTATIC, generatedClassName, FINALIZER_DELEGATE_NAME, 1068 FINALIZER_DELEGATE_METHOD_DESCRIPTOR)); 1069 mv.visitVarInsn(ALOAD, 0); 1070 // ...and invoke it through JavaAdapterServices.invokeNoPermissions 1071 INVOKE_NO_PERMISSIONS.invoke(mv); 1072 mv.visitInsn(RETURN); 1073 endMethod(mv); 1074 } 1075 1076 private static String[] getExceptionNames(final Class<?>[] exceptions) { 1077 final String[] exceptionNames = new String[exceptions.length]; 1078 for (int i = 0; i < exceptions.length; ++i) { 1079 exceptionNames[i] = Type.getInternalName(exceptions[i]); 1080 } 1081 return exceptionNames; 1082 } 1083 1084 private static int getAccessModifiers(final Method method) { 1085 return ACC_PUBLIC | (method.isVarArgs() ? ACC_VARARGS : 0); 1086 } 1087 1088 /** 1089 * Gathers methods that can be implemented or overridden from the specified type into this factory's 1090 * {@link #methodInfos} set. It will add all non-final, non-static methods that are either public or protected from 1091 * the type if the type itself is public. If the type is a class, the method will recursively invoke itself for its 1092 * superclass and the interfaces it implements, and add further methods that were not directly declared on the 1093 * class. 1094 * @param type the type defining the methods. 1095 */ 1096 private void gatherMethods(final Class<?> type) throws AdaptationException { 1097 if (Modifier.isPublic(type.getModifiers())) { 1098 final Method[] typeMethods = type.isInterface() ? type.getMethods() : type.getDeclaredMethods(); 1099 1100 for (final Method typeMethod: typeMethods) { 1101 final String name = typeMethod.getName(); 1102 if(name.startsWith(SUPER_PREFIX)) { 1103 continue; 1104 } 1105 final int m = typeMethod.getModifiers(); 1106 if (Modifier.isStatic(m)) { 1107 continue; 1108 } 1109 if (Modifier.isPublic(m) || Modifier.isProtected(m)) { 1110 // Is it a "finalize()"? 1111 if(name.equals("finalize") && typeMethod.getParameterCount() == 0) { 1112 if(type != Object.class) { 1113 hasExplicitFinalizer = true; 1114 if(Modifier.isFinal(m)) { 1115 // Must be able to override an explicit finalizer 1116 throw new AdaptationException(Outcome.ERROR_FINAL_FINALIZER, type.getCanonicalName()); 1117 } 1118 } 1119 continue; 1120 } 1121 1122 final MethodInfo mi = new MethodInfo(typeMethod); 1123 if (Modifier.isFinal(m) || isCallerSensitive(typeMethod)) { 1124 finalMethods.add(mi); 1125 } else if (!finalMethods.contains(mi) && methodInfos.add(mi) && Modifier.isAbstract(m)) { 1126 abstractMethodNames.add(mi.getName()); 1127 } 1128 } 1129 } 1130 } 1131 // If the type is a class, visit its superclasses and declared interfaces. If it's an interface, we're done. 1132 // Needing to invoke the method recursively for a non-interface Class object is the consequence of needing to 1133 // see all declared protected methods, and Class.getDeclaredMethods() doesn't provide those declared in a 1134 // superclass. For interfaces, we used Class.getMethods(), as we're only interested in public ones there, and 1135 // getMethods() does provide those declared in a superinterface. 1136 if (!type.isInterface()) { 1137 final Class<?> superType = type.getSuperclass(); 1138 if (superType != null) { 1139 gatherMethods(superType); 1140 } 1141 for (final Class<?> itf: type.getInterfaces()) { 1142 gatherMethods(itf); 1143 } 1144 } 1145 } 1146 1147 private void gatherMethods(final List<Class<?>> classes) throws AdaptationException { 1148 for(final Class<?> c: classes) { 1149 gatherMethods(c); 1150 } 1151 } 1152 1153 private static final AccessControlContext GET_DECLARED_MEMBERS_ACC_CTXT = ClassAndLoader.createPermAccCtxt("accessDeclaredMembers"); 1154 1155 /** 1156 * Creates a collection of methods that are not final, but we still never allow them to be overridden in adapters, 1157 * as explicitly declaring them automatically is a bad idea. Currently, this means {@code Object.finalize()} and 1158 * {@code Object.clone()}. 1159 * @return a collection of method infos representing those methods that we never override in adapter classes. 1160 */ 1161 private static Collection<MethodInfo> getExcludedMethods() { 1162 return AccessController.doPrivileged(new PrivilegedAction<Collection<MethodInfo>>() { 1163 @Override 1164 public Collection<MethodInfo> run() { 1165 try { 1166 return Arrays.asList( 1167 new MethodInfo(Object.class, "finalize"), 1168 new MethodInfo(Object.class, "clone")); 1169 } catch (final NoSuchMethodException e) { 1170 throw new AssertionError(e); 1171 } 1172 } 1173 }, GET_DECLARED_MEMBERS_ACC_CTXT); 1174 } 1175 1176 private String getCommonSuperClass(final String type1, final String type2) { 1177 try { 1178 final Class<?> c1 = Class.forName(type1.replace('/', '.'), false, commonLoader); 1179 final Class<?> c2 = Class.forName(type2.replace('/', '.'), false, commonLoader); 1180 if (c1.isAssignableFrom(c2)) { 1181 return type1; 1182 } 1183 if (c2.isAssignableFrom(c1)) { 1184 return type2; 1185 } 1186 if (c1.isInterface() || c2.isInterface()) { 1187 return OBJECT_TYPE.getInternalName(); 1188 } 1189 return assignableSuperClass(c1, c2).getName().replace('.', '/'); 1190 } catch(final ClassNotFoundException e) { 1191 throw new RuntimeException(e); 1192 } 1193 } 1194 1195 private static Class<?> assignableSuperClass(final Class<?> c1, final Class<?> c2) { 1196 final Class<?> superClass = c1.getSuperclass(); 1197 return superClass.isAssignableFrom(c2) ? superClass : assignableSuperClass(superClass, c2); 1198 } 1199 1200 private static boolean isCallerSensitive(final AccessibleObject e) { 1201 return e.isAnnotationPresent(CallerSensitive.class); 1202 } 1203 1204 private static Call lookupServiceMethod(final String name, final Class<?> rtype, final Class<?>... ptypes) { 1205 return staticCallNoLookup(JavaAdapterServices.class, name, rtype, ptypes); 1206 } 1207 }