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.ALOAD;
35 import static jdk.internal.org.objectweb.asm.Opcodes.ASTORE;
36 import static jdk.internal.org.objectweb.asm.Opcodes.D2F;
37 import static jdk.internal.org.objectweb.asm.Opcodes.H_INVOKESTATIC;
38 import static jdk.internal.org.objectweb.asm.Opcodes.INVOKESPECIAL;
39 import static jdk.internal.org.objectweb.asm.Opcodes.I2B;
40 import static jdk.internal.org.objectweb.asm.Opcodes.I2S;
41 import static jdk.internal.org.objectweb.asm.Opcodes.RETURN;
42 import static jdk.nashorn.internal.codegen.CompilerConstants.interfaceCallNoLookup;
43 import static jdk.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup;
44 import static jdk.nashorn.internal.lookup.Lookup.MH;
45 import static jdk.nashorn.internal.runtime.linker.AdaptationResult.Outcome.ERROR_NO_ACCESSIBLE_CONSTRUCTOR;
46
47 import java.lang.invoke.CallSite;
48 import java.lang.invoke.MethodHandle;
49 import java.lang.invoke.MethodHandles.Lookup;
50 import java.lang.invoke.MethodType;
51 import java.lang.reflect.AccessibleObject;
52 import java.lang.reflect.Constructor;
53 import java.lang.reflect.Method;
54 import java.lang.reflect.Modifier;
55 import java.security.AccessControlContext;
56 import java.security.AccessController;
57 import java.security.PrivilegedAction;
58 import java.security.ProtectionDomain;
59 import java.util.Arrays;
60 import java.util.Collection;
61 import java.util.HashSet;
62 import java.util.Iterator;
63 import java.util.List;
64 import java.util.Set;
65 import jdk.internal.org.objectweb.asm.ClassWriter;
66 import jdk.internal.org.objectweb.asm.Handle;
67 import jdk.internal.org.objectweb.asm.Label;
68 import jdk.internal.org.objectweb.asm.Opcodes;
69 import jdk.internal.org.objectweb.asm.Type;
70 import jdk.internal.org.objectweb.asm.commons.InstructionAdapter;
71 import jdk.nashorn.api.scripting.ScriptObjectMirror;
72 import jdk.nashorn.api.scripting.ScriptUtils;
73 import jdk.nashorn.internal.codegen.CompilerConstants.Call;
74 import jdk.nashorn.internal.runtime.ScriptFunction;
75 import jdk.nashorn.internal.runtime.ScriptObject;
76 import jdk.nashorn.internal.runtime.linker.AdaptationResult.Outcome;
77 import jdk.internal.reflect.CallerSensitive;
78
79 /**
80 * Generates bytecode for a Java adapter class. Used by the {@link JavaAdapterFactory}.
81 * </p><p>
82 * For every protected or public constructor in the extended class, the adapter class will have either one or two
83 * public constructors (visibility of protected constructors in the extended class is promoted to public).
84 * <li>
85 * <li>For adapter classes with instance-level overrides, a constructor taking a trailing ScriptObject argument preceded
86 * by original constructor arguments is always created on the adapter class. When such a constructor is invoked, the
87 * passed ScriptObject's member functions are used to implement and/or override methods on the original class,
88 * dispatched by name. A single JavaScript function will act as the implementation for all overloaded methods of the
89 * same name. When methods on an adapter instance are invoked, the functions are invoked having the ScriptObject passed
90 * in the instance constructor as their "this". Subsequent changes to the ScriptObject (reassignment or removal of its
91 * functions) will be reflected in the adapter instance as it is live dispatching to its members on every method invocation.
92 * {@code java.lang.Object} methods {@code equals}, {@code hashCode}, and {@code toString} can also be overridden. The
93 * only restriction is that since every JavaScript object already has a {@code toString} function through the
94 * {@code Object.prototype}, the {@code toString} in the adapter is only overridden if the passed ScriptObject has a
95 * {@code toString} function as its own property, and not inherited from a prototype. All other adapter methods can be
96 * implemented or overridden through a prototype-inherited function of the ScriptObject passed to the constructor too.
97 * </li>
98 * <li>
99 * If the original types collectively have only one abstract method, or have several of them, but all share the
100 * same name, an additional constructor for instance-level override adapter is provided for every original constructor;
101 * this one takes a ScriptFunction as its last argument preceded by original constructor arguments. This constructor
102 * will use the passed function as the implementation for all abstract methods. For consistency, any concrete methods
103 * sharing the single abstract method name will also be overridden by the function. When methods on the adapter instance
104 * are invoked, the ScriptFunction is invoked with UNDEFINED or Global as its "this" depending whether the function is
105 * strict or not.
106 * </li>
107 * <li>
108 * If the adapter being generated has class-level overrides, constructors taking same arguments as the superclass
109 * constructors are created. These constructors simply delegate to the superclass constructor. They are simply used to
110 * create instances of the adapter class, with no instance-level overrides, as they don't have them. If the original
111 * class' constructor was variable arity, the adapter constructor will also be variable arity. Protected constructors
112 * are exposed as public.
113 * </li>
114 * </ul>
115 * </p><p>
116 * For adapter methods that return values, all the JavaScript-to-Java conversions supported by Nashorn will be in effect
117 * to coerce the JavaScript function return value to the expected Java return type.
118 * </p><p>
119 * Since we are adding a trailing argument to the generated constructors in the adapter class with instance-level overrides, they will never be
120 * declared as variable arity, even if the original constructor in the superclass was declared as variable arity. The
121 * reason we are passing the additional argument at the end of the argument list instead at the front is that the
122 * source-level script expression <code>new X(a, b) { ... }</code> (which is a proprietary syntax extension Nashorn uses
123 * to resemble Java anonymous classes) is actually equivalent to <code>new X(a, b, { ... })</code>.
124 * </p><p>
125 * It is possible to create two different adapter classes: those that can have class-level overrides, and those that can
126 * have instance-level overrides. When {@link JavaAdapterFactory#getAdapterClassFor(Class[], ScriptObject, ProtectionDomain)}
127 * or {@link JavaAdapterFactory#getAdapterClassFor(Class[], ScriptObject, Lookup)} is invoked
128 * with non-null {@code classOverrides} parameter, an adapter class is created that can have class-level overrides, and
129 * the passed script object will be used as the implementations for its methods, just as in the above case of the
130 * constructor taking a script object. Note that in the case of class-level overrides, a new adapter class is created on
131 * every invocation, and the implementation object is bound to the class, not to any instance. All created instances
132 * will share these functions. If it is required to have both class-level overrides and instance-level overrides, the
133 * class-level override adapter class should be subclassed with an instance-override adapter. Since adapters delegate to
134 * super class when an overriding method handle is not specified, this will behave as expected. It is not possible to
135 * have both class-level and instance-level overrides in the same class for security reasons: adapter classes are
136 * defined with a protection domain of their creator code, and an adapter class that has both class and instance level
137 * overrides would need to have two potentially different protection domains: one for class-based behavior and one for
138 * instance-based behavior; since Java classes can only belong to a single protection domain, this could not be
139 * implemented securely.
140 */
141 final class JavaAdapterBytecodeGenerator {
142 // Field names in adapters
143 private static final String GLOBAL_FIELD_NAME = "global";
144 private static final String DELEGATE_FIELD_NAME = "delegate";
145 private static final String IS_FUNCTION_FIELD_NAME = "isFunction";
146 private static final String CALL_THIS_FIELD_NAME = "callThis";
147
148 // Initializer names
149 private static final String INIT = "<init>";
150 private static final String CLASS_INIT = "<clinit>";
151
152 // Types often used in generated bytecode
153 private static final Type OBJECT_TYPE = Type.getType(Object.class);
154 private static final Type SCRIPT_OBJECT_TYPE = Type.getType(ScriptObject.class);
155 private static final Type SCRIPT_FUNCTION_TYPE = Type.getType(ScriptFunction.class);
156 private static final Type SCRIPT_OBJECT_MIRROR_TYPE = Type.getType(ScriptObjectMirror.class);
157
158 // JavaAdapterServices methods used in generated bytecode
159 private static final Call CHECK_FUNCTION = lookupServiceMethod("checkFunction", ScriptFunction.class, Object.class, String.class);
160 private static final Call EXPORT_RETURN_VALUE = lookupServiceMethod("exportReturnValue", Object.class, Object.class);
161 private static final Call GET_CALL_THIS = lookupServiceMethod("getCallThis", Object.class, ScriptFunction.class, Object.class);
162 private static final Call GET_CLASS_OVERRIDES = lookupServiceMethod("getClassOverrides", ScriptObject.class);
163 private static final Call GET_NON_NULL_GLOBAL = lookupServiceMethod("getNonNullGlobal", ScriptObject.class);
164 private static final Call HAS_OWN_TO_STRING = lookupServiceMethod("hasOwnToString", boolean.class, ScriptObject.class);
165 private static final Call INVOKE_NO_PERMISSIONS = lookupServiceMethod("invokeNoPermissions", void.class, MethodHandle.class, Object.class);
166 private static final Call NOT_AN_OBJECT = lookupServiceMethod("notAnObject", void.class, Object.class);
167 private static final Call SET_GLOBAL = lookupServiceMethod("setGlobal", Runnable.class, ScriptObject.class);
168 private static final Call TO_CHAR_PRIMITIVE = lookupServiceMethod("toCharPrimitive", char.class, Object.class);
169 private static final Call UNSUPPORTED = lookupServiceMethod("unsupported", UnsupportedOperationException.class);
170 private static final Call WRAP_THROWABLE = lookupServiceMethod("wrapThrowable", RuntimeException.class, Throwable.class);
171 private static final Call UNWRAP_MIRROR = lookupServiceMethod("unwrapMirror", ScriptObject.class, Object.class, boolean.class);
172
173 // Other methods invoked by the generated bytecode
174 private static final Call UNWRAP = staticCallNoLookup(ScriptUtils.class, "unwrap", Object.class, Object.class);
175 private static final Call CHAR_VALUE_OF = staticCallNoLookup(Character.class, "valueOf", Character.class, char.class);
176 private static final Call DOUBLE_VALUE_OF = staticCallNoLookup(Double.class, "valueOf", Double.class, double.class);
177 private static final Call LONG_VALUE_OF = staticCallNoLookup(Long.class, "valueOf", Long.class, long.class);
178 private static final Call RUN = interfaceCallNoLookup(Runnable.class, "run", void.class);
179
180 // ASM handle to the bootstrap method
181 private static final Handle BOOTSTRAP_HANDLE = new Handle(H_INVOKESTATIC,
182 Type.getInternalName(JavaAdapterServices.class), "bootstrap",
183 MethodType.methodType(CallSite.class, Lookup.class, String.class,
184 MethodType.class, int.class).toMethodDescriptorString(), false);
185
186 // ASM handle to the bootstrap method for array populator
187 private static final Handle CREATE_ARRAY_BOOTSTRAP_HANDLE = new Handle(H_INVOKESTATIC,
188 Type.getInternalName(JavaAdapterServices.class), "createArrayBootstrap",
189 MethodType.methodType(CallSite.class, Lookup.class, String.class,
190 MethodType.class).toMethodDescriptorString(), false);
191
192 // Field type names used in the generated bytecode
193 private static final String SCRIPT_OBJECT_TYPE_DESCRIPTOR = SCRIPT_OBJECT_TYPE.getDescriptor();
194 private static final String OBJECT_TYPE_DESCRIPTOR = OBJECT_TYPE.getDescriptor();
195 private static final String BOOLEAN_TYPE_DESCRIPTOR = Type.BOOLEAN_TYPE.getDescriptor();
196
197 // Throwable names used in the generated bytecode
198 private static final String RUNTIME_EXCEPTION_TYPE_NAME = Type.getInternalName(RuntimeException.class);
199 private static final String ERROR_TYPE_NAME = Type.getInternalName(Error.class);
200 private static final String THROWABLE_TYPE_NAME = Type.getInternalName(Throwable.class);
201
202 // Some more frequently used method descriptors
203 private static final String GET_METHOD_PROPERTY_METHOD_DESCRIPTOR = Type.getMethodDescriptor(OBJECT_TYPE, SCRIPT_OBJECT_TYPE);
204 private static final String VOID_METHOD_DESCRIPTOR = Type.getMethodDescriptor(Type.VOID_TYPE);
205
206 private static final String ADAPTER_PACKAGE_INTERNAL = "jdk/nashorn/javaadapters/";
207 private static final int MAX_GENERATED_TYPE_NAME_LENGTH = 255;
208
209 // Method name prefix for invoking super-methods
210 static final String SUPER_PREFIX = "super$";
211
212 // Method name and type for the no-privilege finalizer delegate
213 private static final String FINALIZER_DELEGATE_NAME = "$$nashornFinalizerDelegate";
214 private static final String FINALIZER_DELEGATE_METHOD_DESCRIPTOR = Type.getMethodDescriptor(Type.VOID_TYPE, OBJECT_TYPE);
215
216 /**
217 * Collection of methods we never override: Object.clone(), Object.finalize().
218 */
219 private static final Collection<MethodInfo> EXCLUDED = getExcludedMethods();
220
221 // This is the superclass for our generated adapter.
222 private final Class<?> superClass;
223 // Interfaces implemented by our generated adapter.
224 private final List<Class<?>> interfaces;
225 // Class loader used as the parent for the class loader we'll create to load the generated class. It will be a class
226 // loader that has the visibility of all original types (class to extend and interfaces to implement) and of the
227 // Nashorn classes.
228 private final ClassLoader commonLoader;
229 // Is this a generator for the version of the class that can have overrides on the class level?
230 private final boolean classOverride;
231 // Binary name of the superClass
232 private final String superClassName;
233 // Binary name of the generated class.
234 private final String generatedClassName;
235 private final Set<String> abstractMethodNames = new HashSet<>();
236 private final String samName;
237 private final Set<MethodInfo> finalMethods = new HashSet<>(EXCLUDED);
238 private final Set<MethodInfo> methodInfos = new HashSet<>();
239 private final boolean autoConvertibleFromFunction;
240 private boolean hasExplicitFinalizer = false;
241
242 private final ClassWriter cw;
243
244 /**
245 * Creates a generator for the bytecode for the adapter for the specified superclass and interfaces.
246 * @param superClass the superclass the adapter will extend.
247 * @param interfaces the interfaces the adapter will implement.
248 * @param commonLoader the class loader that can see all of superClass, interfaces, and Nashorn classes.
249 * @param classOverride true to generate the bytecode for the adapter that has class-level overrides, false to
250 * generate the bytecode for the adapter that has instance-level overrides.
251 * @throws AdaptationException if the adapter can not be generated for some reason.
252 */
253 JavaAdapterBytecodeGenerator(final Class<?> superClass, final List<Class<?>> interfaces,
254 final ClassLoader commonLoader, final boolean classOverride) throws AdaptationException {
255 assert superClass != null && !superClass.isInterface();
256 assert interfaces != null;
257
258 this.superClass = superClass;
259 this.interfaces = interfaces;
260 this.classOverride = classOverride;
261 this.commonLoader = commonLoader;
262 cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS) {
263 @Override
264 protected String getCommonSuperClass(final String type1, final String type2) {
265 // We need to override ClassWriter.getCommonSuperClass to use this factory's commonLoader as a class
266 // loader to find the common superclass of two types when needed.
267 return JavaAdapterBytecodeGenerator.this.getCommonSuperClass(type1, type2);
268 }
269 };
270 superClassName = Type.getInternalName(superClass);
271 generatedClassName = getGeneratedClassName(superClass, interfaces);
272
273 cw.visit(Opcodes.V1_8, ACC_PUBLIC | ACC_SUPER, generatedClassName, null, superClassName, getInternalTypeNames(interfaces));
274 generateField(GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
275 generateField(DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
276
277 gatherMethods(superClass);
278 gatherMethods(interfaces);
279 if (abstractMethodNames.size() == 1) {
280 samName = abstractMethodNames.iterator().next();
281 generateField(CALL_THIS_FIELD_NAME, OBJECT_TYPE_DESCRIPTOR);
282 generateField(IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);
283 } else {
284 samName = null;
285 }
286 if(classOverride) {
287 generateClassInit();
288 }
289 autoConvertibleFromFunction = generateConstructors();
290 generateMethods();
291 generateSuperMethods();
292 if (hasExplicitFinalizer) {
293 generateFinalizerMethods();
294 }
295 // }
296 cw.visitEnd();
297 }
298
299 private void generateField(final String name, final String fieldDesc) {
300 cw.visitField(ACC_PRIVATE | ACC_FINAL | (classOverride ? ACC_STATIC : 0), name, fieldDesc, null, null).visitEnd();
301 }
302
303 JavaAdapterClassLoader createAdapterClassLoader() {
304 return new JavaAdapterClassLoader(generatedClassName, cw.toByteArray());
305 }
306
307 boolean isAutoConvertibleFromFunction() {
308 return autoConvertibleFromFunction;
309 }
310
311 private static String getGeneratedClassName(final Class<?> superType, final List<Class<?>> interfaces) {
312 // The class we use to primarily name our adapter is either the superclass, or if it is Object (meaning we're
313 // just implementing interfaces or extending Object), then the first implemented interface or Object.
314 final Class<?> namingType = superType == Object.class ? (interfaces.isEmpty()? Object.class : interfaces.get(0)) : superType;
315 final Package pkg = namingType.getPackage();
316 final String namingTypeName = Type.getInternalName(namingType);
317 final StringBuilder buf = new StringBuilder();
318 buf.append(ADAPTER_PACKAGE_INTERNAL).append(namingTypeName.replace('/', '_'));
319 final Iterator<Class<?>> it = interfaces.iterator();
320 if(superType == Object.class && it.hasNext()) {
321 it.next(); // Skip first interface, it was used to primarily name the adapter
322 }
323 // Append interface names to the adapter name
324 while(it.hasNext()) {
325 buf.append("$$").append(it.next().getSimpleName());
326 }
327 return buf.toString().substring(0, Math.min(MAX_GENERATED_TYPE_NAME_LENGTH, buf.length()));
328 }
329
330 /**
331 * Given a list of class objects, return an array with their binary names. Used to generate the array of interface
332 * names to implement.
333 * @param classes the classes
334 * @return an array of names
335 */
336 private static String[] getInternalTypeNames(final List<Class<?>> classes) {
337 final int interfaceCount = classes.size();
338 final String[] interfaceNames = new String[interfaceCount];
339 for(int i = 0; i < interfaceCount; ++i) {
340 interfaceNames[i] = Type.getInternalName(classes.get(i));
341 }
342 return interfaceNames;
343 }
344
345 private void generateClassInit() {
346 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_STATIC, CLASS_INIT,
347 VOID_METHOD_DESCRIPTOR, null, null));
348
349 // Assign "global = Context.getGlobal()"
350 GET_NON_NULL_GLOBAL.invoke(mv);
351 mv.putstatic(generatedClassName, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
352
353 GET_CLASS_OVERRIDES.invoke(mv);
354 if(samName != null) {
355 // If the class is a SAM, allow having ScriptFunction passed as class overrides
356 mv.dup();
357 mv.instanceOf(SCRIPT_FUNCTION_TYPE);
358 mv.dup();
359 mv.putstatic(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);
360 final Label notFunction = new Label();
361 mv.ifeq(notFunction);
362 mv.dup();
363 mv.checkcast(SCRIPT_FUNCTION_TYPE);
364 emitInitCallThis(mv);
365 mv.visitLabel(notFunction);
366 }
367 mv.putstatic(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
368
369 endInitMethod(mv);
370 }
371
372 /**
373 * Emit bytecode for initializing the "callThis" field.
374 */
375 private void emitInitCallThis(final InstructionAdapter mv) {
376 loadField(mv, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
377 GET_CALL_THIS.invoke(mv);
378 if(classOverride) {
379 mv.putstatic(generatedClassName, CALL_THIS_FIELD_NAME, OBJECT_TYPE_DESCRIPTOR);
380 } else {
381 // It is presumed ALOAD 0 was already executed
382 mv.putfield(generatedClassName, CALL_THIS_FIELD_NAME, OBJECT_TYPE_DESCRIPTOR);
383 }
384 }
385
386 private boolean generateConstructors() throws AdaptationException {
387 boolean gotCtor = false;
388 boolean canBeAutoConverted = false;
389 for (final Constructor<?> ctor: superClass.getDeclaredConstructors()) {
390 final int modifier = ctor.getModifiers();
391 if((modifier & (Modifier.PUBLIC | Modifier.PROTECTED)) != 0 && !isCallerSensitive(ctor)) {
392 canBeAutoConverted = generateConstructors(ctor) | canBeAutoConverted;
393 gotCtor = true;
394 }
395 }
396 if(!gotCtor) {
397 throw new AdaptationException(ERROR_NO_ACCESSIBLE_CONSTRUCTOR, superClass.getCanonicalName());
398 }
399 return canBeAutoConverted;
400 }
401
402 private boolean generateConstructors(final Constructor<?> ctor) {
403 if(classOverride) {
404 // Generate a constructor that just delegates to ctor. This is used with class-level overrides, when we want
405 // to create instances without further per-instance overrides.
406 generateDelegatingConstructor(ctor);
407 return false;
408 }
409
410 // Generate a constructor that delegates to ctor, but takes an additional ScriptObject parameter at the
411 // beginning of its parameter list.
412 generateOverridingConstructor(ctor, false);
413
414 if (samName == null) {
415 return false;
416 }
417 // If all our abstract methods have a single name, generate an additional constructor, one that takes a
418 // ScriptFunction as its first parameter and assigns it as the implementation for all abstract methods.
419 generateOverridingConstructor(ctor, true);
420 // If the original type only has a single abstract method name, as well as a default ctor, then it can
421 // be automatically converted from JS function.
422 return ctor.getParameterTypes().length == 0;
423 }
424
425 private void generateDelegatingConstructor(final Constructor<?> ctor) {
426 final Type originalCtorType = Type.getType(ctor);
427 final Type[] argTypes = originalCtorType.getArgumentTypes();
428
429 // All constructors must be public, even if in the superclass they were protected.
430 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC |
431 (ctor.isVarArgs() ? ACC_VARARGS : 0), INIT,
432 Type.getMethodDescriptor(originalCtorType.getReturnType(), argTypes), null, null));
433
434 mv.visitCode();
435 emitSuperConstructorCall(mv, originalCtorType.getDescriptor());
436
437 endInitMethod(mv);
438 }
439
440 /**
441 * Generates a constructor for the instance adapter class. This constructor will take the same arguments as the supertype
442 * constructor passed as the argument here, and delegate to it. However, it will take an additional argument of
443 * either ScriptObject or ScriptFunction type (based on the value of the "fromFunction" parameter), and initialize
444 * all the method handle fields of the adapter instance with functions from the script object (or the script
445 * function itself, if that's what's passed). Additionally, it will create another constructor with an additional
446 * Object type parameter that can be used for ScriptObjectMirror objects.
447 * The constructor will also store the Nashorn global that was current at the constructor
448 * invocation time in a field named "global". The generated constructor will be public, regardless of whether the
449 * supertype constructor was public or protected. The generated constructor will not be variable arity, even if the
450 * supertype constructor was.
451 * @param ctor the supertype constructor that is serving as the base for the generated constructor.
452 * @param fromFunction true if we're generating a constructor that initializes SAM types from a single
453 * ScriptFunction passed to it, false if we're generating a constructor that initializes an arbitrary type from a
454 * ScriptObject passed to it.
455 */
456 private void generateOverridingConstructor(final Constructor<?> ctor, final boolean fromFunction) {
457 final Type originalCtorType = Type.getType(ctor);
458 final Type[] originalArgTypes = originalCtorType.getArgumentTypes();
459 final int argLen = originalArgTypes.length;
460 final Type[] newArgTypes = new Type[argLen + 1];
461
462 // Insert ScriptFunction|ScriptObject as the last argument to the constructor
463 final Type extraArgumentType = fromFunction ? SCRIPT_FUNCTION_TYPE : SCRIPT_OBJECT_TYPE;
464 newArgTypes[argLen] = extraArgumentType;
465 System.arraycopy(originalArgTypes, 0, newArgTypes, 0, argLen);
466
467 // All constructors must be public, even if in the superclass they were protected.
468 // Existing super constructor <init>(this, args...) triggers generating <init>(this, args..., delegate).
469 // Any variable arity constructors become fixed-arity with explicit array arguments.
470 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, INIT,
471 Type.getMethodDescriptor(originalCtorType.getReturnType(), newArgTypes), null, null));
472
473 mv.visitCode();
474 // First, invoke super constructor with original arguments.
475 final int extraArgOffset = emitSuperConstructorCall(mv, originalCtorType.getDescriptor());
476
477 // Assign "this.global = Context.getGlobal()"
478 mv.visitVarInsn(ALOAD, 0);
479 GET_NON_NULL_GLOBAL.invoke(mv);
480 mv.putfield(generatedClassName, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
481
482 // Assign "this.delegate = delegate"
483 mv.visitVarInsn(ALOAD, 0);
484 mv.visitVarInsn(ALOAD, extraArgOffset);
485 mv.putfield(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
486
487 if (fromFunction) {
488 // Assign "isFunction = true"
489 mv.visitVarInsn(ALOAD, 0);
490 mv.iconst(1);
491 mv.putfield(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);
492
493 mv.visitVarInsn(ALOAD, 0);
494 mv.visitVarInsn(ALOAD, extraArgOffset);
495 emitInitCallThis(mv);
496 }
497
498 endInitMethod(mv);
499
500 if (! fromFunction) {
501 newArgTypes[argLen] = OBJECT_TYPE;
502 final InstructionAdapter mv2 = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, INIT,
503 Type.getMethodDescriptor(originalCtorType.getReturnType(), newArgTypes), null, null));
504 generateOverridingConstructorWithObjectParam(mv2, originalCtorType.getDescriptor());
505 }
506 }
507
508 // Object additional param accepting constructor for handling ScriptObjectMirror objects, which are
509 // unwrapped to work as ScriptObjects or ScriptFunctions. This also handles null and undefined values for
510 // script adapters by throwing TypeError on such script adapters.
511 private void generateOverridingConstructorWithObjectParam(final InstructionAdapter mv, final String ctorDescriptor) {
512 mv.visitCode();
513 final int extraArgOffset = emitSuperConstructorCall(mv, ctorDescriptor);
514
515 // Check for ScriptObjectMirror
516 mv.visitVarInsn(ALOAD, extraArgOffset);
517 mv.instanceOf(SCRIPT_OBJECT_MIRROR_TYPE);
518 final Label notMirror = new Label();
519 mv.ifeq(notMirror);
520
521 mv.visitVarInsn(ALOAD, 0);
522 mv.visitVarInsn(ALOAD, extraArgOffset);
523 mv.iconst(0);
524 UNWRAP_MIRROR.invoke(mv);
525 mv.putfield(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
526
527 mv.visitVarInsn(ALOAD, 0);
528 mv.visitVarInsn(ALOAD, extraArgOffset);
529 mv.iconst(1);
530 UNWRAP_MIRROR.invoke(mv);
531 mv.putfield(generatedClassName, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
532
533 final Label done = new Label();
534
535 if (samName != null) {
536 mv.visitVarInsn(ALOAD, 0);
537 mv.getfield(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
538 mv.instanceOf(SCRIPT_FUNCTION_TYPE);
539 mv.ifeq(done);
540
541 // Assign "isFunction = true"
542 mv.visitVarInsn(ALOAD, 0);
543 mv.iconst(1);
544 mv.putfield(generatedClassName, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);
545
546 mv.visitVarInsn(ALOAD, 0);
547 mv.dup();
548 mv.getfield(generatedClassName, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
549 mv.checkcast(SCRIPT_FUNCTION_TYPE);
550 emitInitCallThis(mv);
551 mv.goTo(done);
552 }
553
554 mv.visitLabel(notMirror);
555
556 // Throw error if not a ScriptObject
557 mv.visitVarInsn(ALOAD, extraArgOffset);
558 NOT_AN_OBJECT.invoke(mv);
559
560 mv.visitLabel(done);
561 endInitMethod(mv);
562 }
563
564 private static void endInitMethod(final InstructionAdapter mv) {
565 mv.visitInsn(RETURN);
566 endMethod(mv);
567 }
568
569 private static void endMethod(final InstructionAdapter mv) {
570 mv.visitMaxs(0, 0);
571 mv.visitEnd();
572 }
573
574 /**
575 * Encapsulation of the information used to generate methods in the adapter classes. Basically, a wrapper around the
576 * reflective Method object, a cached MethodType, and the name of the field in the adapter class that will hold the
577 * method handle serving as the implementation of this method in adapter instances.
578 *
579 */
580 private static class MethodInfo {
581 private final Method method;
582 private final MethodType type;
583
584 private MethodInfo(final Class<?> clazz, final String name, final Class<?>... argTypes) throws NoSuchMethodException {
585 this(clazz.getDeclaredMethod(name, argTypes));
586 }
587
588 private MethodInfo(final Method method) {
589 this.method = method;
590 this.type = MH.type(method.getReturnType(), method.getParameterTypes());
591 }
592
593 @Override
594 public boolean equals(final Object obj) {
595 return obj instanceof MethodInfo && equals((MethodInfo)obj);
596 }
597
598 private boolean equals(final MethodInfo other) {
599 // Only method name and type are used for comparison; method handle field name is not.
600 return getName().equals(other.getName()) && type.equals(other.type);
601 }
602
603 String getName() {
604 return method.getName();
605 }
606
607 @Override
608 public int hashCode() {
609 return getName().hashCode() ^ type.hashCode();
610 }
611 }
612
613 private void generateMethods() {
614 for(final MethodInfo mi: methodInfos) {
615 generateMethod(mi);
616 }
617 }
618
619 /**
620 * Generates a method in the adapter class that adapts a method from the
621 * original class. The generated method will either invoke the delegate
622 * using a CALL dynamic operation call site (if it is a SAM method and the
623 * delegate is a ScriptFunction), or invoke GET_METHOD_PROPERTY dynamic
624 * operation with the method name as the argument and then invoke the
625 * returned ScriptFunction using the CALL dynamic operation. If
626 * GET_METHOD_PROPERTY returns null or undefined (that is, the JS object
627 * doesn't provide an implementation for the method) then the method will
628 * either do a super invocation to base class, or if the method is abstract,
629 * throw an {@link UnsupportedOperationException}. Finally, if
630 * GET_METHOD_PROPERTY returns something other than a ScriptFunction, null,
631 * or undefined, a TypeError is thrown. The current Global is checked before
632 * the dynamic operations, and if it is different than the Global used to
633 * create the adapter, the creating Global is set to be the current Global.
634 * In this case, the previously current Global is restored after the
635 * invocation. If CALL results in a Throwable that is not one of the
636 * method's declared exceptions, and is not an unchecked throwable, then it
637 * is wrapped into a {@link RuntimeException} and the runtime exception is
638 * thrown.
639 * @param mi the method info describing the method to be generated.
640 */
641 private void generateMethod(final MethodInfo mi) {
642 final Method method = mi.method;
643 final Class<?>[] exceptions = method.getExceptionTypes();
644 final String[] exceptionNames = getExceptionNames(exceptions);
645 final MethodType type = mi.type;
646 final String methodDesc = type.toMethodDescriptorString();
647 final String name = mi.getName();
648
649 final Type asmType = Type.getMethodType(methodDesc);
650 final Type[] asmArgTypes = asmType.getArgumentTypes();
651
652 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(getAccessModifiers(method), name,
653 methodDesc, null, exceptionNames));
654 mv.visitCode();
655
656 final Class<?> returnType = type.returnType();
657 final Type asmReturnType = Type.getType(returnType);
658
659 // Determine the first index for a local variable
660 int nextLocalVar = 1; // "this" is at 0
661 for(final Type t: asmArgTypes) {
662 nextLocalVar += t.getSize();
663 }
664 // Set our local variable index
665 final int globalRestoringRunnableVar = nextLocalVar++;
666
667 // Load the creatingGlobal object
668 loadField(mv, GLOBAL_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
669
670 // stack: [creatingGlobal]
671 SET_GLOBAL.invoke(mv);
672 // stack: [runnable]
673 mv.visitVarInsn(ASTORE, globalRestoringRunnableVar);
674 // stack: []
675
676 final Label tryBlockStart = new Label();
677 mv.visitLabel(tryBlockStart);
678
679 final Label callCallee = new Label();
680 final Label defaultBehavior = new Label();
681 // If this is a SAM type...
682 if (samName != null) {
683 // ...every method will be checking whether we're initialized with a
684 // function.
685 loadField(mv, IS_FUNCTION_FIELD_NAME, BOOLEAN_TYPE_DESCRIPTOR);
686 // stack: [isFunction]
687 if (name.equals(samName)) {
688 final Label notFunction = new Label();
689 mv.ifeq(notFunction);
690 // stack: []
691 // If it's a SAM method, it'll load delegate as the "callee" and
692 // "callThis" as "this" for the call if delegate is a function.
693 loadField(mv, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
694 // NOTE: if we added "mv.checkcast(SCRIPT_FUNCTION_TYPE);" here
695 // we could emit the invokedynamic CALL instruction with signature
696 // (ScriptFunction, Object, ...) instead of (Object, Object, ...).
697 // We could combine this with an optimization in
698 // ScriptFunction.findCallMethod where it could link a call with a
699 // thinner guard when the call site statically guarantees that the
700 // callee argument is a ScriptFunction. Additionally, we could use
701 // a "ScriptFunction function" field in generated classes instead
702 // of a "boolean isFunction" field to avoid the checkcast.
703 loadField(mv, CALL_THIS_FIELD_NAME, OBJECT_TYPE_DESCRIPTOR);
704 // stack: [callThis, delegate]
705 mv.goTo(callCallee);
706 mv.visitLabel(notFunction);
707 } else {
708 // If it's not a SAM method, and the delegate is a function,
709 // it'll fall back to default behavior
710 mv.ifne(defaultBehavior);
711 // stack: []
712 }
713 }
714
715 // At this point, this is either not a SAM method or the delegate is
716 // not a ScriptFunction. We need to emit a GET_METHOD_PROPERTY Nashorn
717 // invokedynamic.
718
719 if(name.equals("toString")) {
720 // Since every JS Object has a toString, we only override
721 // "String toString()" it if it's explicitly specified on the object.
722 loadField(mv, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
723 // stack: [delegate]
724 HAS_OWN_TO_STRING.invoke(mv);
725 // stack: [hasOwnToString]
726 mv.ifeq(defaultBehavior);
727 }
728
729 loadField(mv, DELEGATE_FIELD_NAME, SCRIPT_OBJECT_TYPE_DESCRIPTOR);
730 mv.dup();
731 // stack: [delegate, delegate]
732 final String encodedName = NameCodec.encode(name);
733 mv.visitInvokeDynamicInsn(encodedName,
734 GET_METHOD_PROPERTY_METHOD_DESCRIPTOR, BOOTSTRAP_HANDLE,
735 NashornCallSiteDescriptor.GET_METHOD_PROPERTY);
736 // stack: [callee, delegate]
737 mv.visitLdcInsn(name);
738 // stack: [name, callee, delegate]
739 CHECK_FUNCTION.invoke(mv);
740 // stack: [fnCalleeOrNull, delegate]
741 final Label hasFunction = new Label();
742 mv.dup();
743 // stack: [fnCalleeOrNull, fnCalleeOrNull, delegate]
744 mv.ifnonnull(hasFunction);
745 // stack: [null, delegate]
746 // If it's null or undefined, clear stack and fall back to default
747 // behavior.
748 mv.pop2();
749 // stack: []
750
751 // We can also arrive here from check for "delegate instanceof ScriptFunction"
752 // in a non-SAM method as well as from a check for "hasOwnToString(delegate)"
753 // for a toString delegate.
754 mv.visitLabel(defaultBehavior);
755 final Runnable emitFinally = ()->emitFinally(mv, globalRestoringRunnableVar);
756 final Label normalFinally = new Label();
757 if(Modifier.isAbstract(method.getModifiers())) {
758 // If the super method is abstract, throw UnsupportedOperationException
759 UNSUPPORTED.invoke(mv);
760 // NOTE: no need to invoke emitFinally.run() as we're inside the
761 // tryBlockStart/tryBlockEnd range, so throwing this exception will
762 // transfer control to the rethrow handler and the finally block in it
763 // will execute.
764 mv.athrow();
765 } else {
766 // If the super method is not abstract, delegate to it.
767 emitSuperCall(mv, method.getDeclaringClass(), name, methodDesc);
768 mv.goTo(normalFinally);
769 }
770
771 mv.visitLabel(hasFunction);
772 // stack: [callee, delegate]
773 mv.swap();
774 // stack [delegate, callee]
775 mv.visitLabel(callCallee);
776
777
778 // Load all parameters back on stack for dynamic invocation.
779
780 int varOffset = 1;
781 // If the param list length is more than 253 slots, we can't invoke it
782 // directly as with (callee, this) it'll exceed 255.
783 final boolean isVarArgCall = getParamListLengthInSlots(asmArgTypes) > 253;
784 for (final Type t : asmArgTypes) {
785 mv.load(varOffset, t);
786 convertParam(mv, t, isVarArgCall);
787 varOffset += t.getSize();
788 }
789 // stack: [args..., callee, delegate]
790
791 // If the resulting parameter list length is too long...
792 if (isVarArgCall) {
793 // ... we pack the parameters (except callee and this) into an array
794 // and use Nashorn vararg invocation.
795 mv.visitInvokeDynamicInsn(NameCodec.EMPTY_NAME,
796 getArrayCreatorMethodType(type).toMethodDescriptorString(),
797 CREATE_ARRAY_BOOTSTRAP_HANDLE);
798 }
799
800 // Invoke the target method handle
801 mv.visitInvokeDynamicInsn(encodedName,
802 getCallMethodType(isVarArgCall, type).toMethodDescriptorString(),
803 BOOTSTRAP_HANDLE, NashornCallSiteDescriptor.CALL);
804 // stack: [returnValue]
805 convertReturnValue(mv, returnType);
806 mv.visitLabel(normalFinally);
807 emitFinally.run();
808 mv.areturn(asmReturnType);
809
810 // If Throwable is not declared, we need an adapter from Throwable to RuntimeException
811 final boolean throwableDeclared = isThrowableDeclared(exceptions);
812 final Label throwableHandler;
813 if (!throwableDeclared) {
814 // Add "throw new RuntimeException(Throwable)" handler for Throwable
815 throwableHandler = new Label();
816 mv.visitLabel(throwableHandler);
817 WRAP_THROWABLE.invoke(mv);
818 // Fall through to rethrow handler
819 } else {
820 throwableHandler = null;
821 }
822 final Label rethrowHandler = new Label();
823 mv.visitLabel(rethrowHandler);
824 // Rethrow handler for RuntimeException, Error, and all declared exception types
825 emitFinally.run();
826 mv.athrow();
827
828 if(throwableDeclared) {
829 mv.visitTryCatchBlock(tryBlockStart, normalFinally, rethrowHandler, THROWABLE_TYPE_NAME);
830 assert throwableHandler == null;
831 } else {
832 mv.visitTryCatchBlock(tryBlockStart, normalFinally, rethrowHandler, RUNTIME_EXCEPTION_TYPE_NAME);
833 mv.visitTryCatchBlock(tryBlockStart, normalFinally, rethrowHandler, ERROR_TYPE_NAME);
834 for(final String excName: exceptionNames) {
835 mv.visitTryCatchBlock(tryBlockStart, normalFinally, rethrowHandler, excName);
836 }
837 mv.visitTryCatchBlock(tryBlockStart, normalFinally, throwableHandler, THROWABLE_TYPE_NAME);
838 }
839 endMethod(mv);
840 }
841
842 private static MethodType getCallMethodType(final boolean isVarArgCall, final MethodType type) {
843 final Class<?>[] callParamTypes;
844 if (isVarArgCall) {
845 // Variable arity calls are always (Object callee, Object this, Object[] params)
846 callParamTypes = new Class<?>[] { Object.class, Object.class, Object[].class };
847 } else {
848 // Adjust invocation type signature for conversions we instituted in
849 // convertParam; also, byte and short get passed as ints.
850 final Class<?>[] origParamTypes = type.parameterArray();
851 callParamTypes = new Class<?>[origParamTypes.length + 2];
852 callParamTypes[0] = Object.class; // callee; could be ScriptFunction.class ostensibly
853 callParamTypes[1] = Object.class; // this
854 for(int i = 0; i < origParamTypes.length; ++i) {
855 callParamTypes[i + 2] = getNashornParamType(origParamTypes[i], false);
856 }
857 }
858 return MethodType.methodType(getNashornReturnType(type.returnType()), callParamTypes);
859 }
860
861 private static MethodType getArrayCreatorMethodType(final MethodType type) {
862 final Class<?>[] callParamTypes = type.parameterArray();
863 for(int i = 0; i < callParamTypes.length; ++i) {
864 callParamTypes[i] = getNashornParamType(callParamTypes[i], true);
865 }
866 return MethodType.methodType(Object[].class, callParamTypes);
867 }
868
869 private static Class<?> getNashornParamType(final Class<?> clazz, final boolean varArg) {
870 if (clazz == byte.class || clazz == short.class) {
871 return int.class;
872 } else if (clazz == float.class) {
873 // If using variable arity, we'll pass a Double instead of double
874 // so that floats don't extend the length of the parameter list.
875 // We return Object.class instead of Double.class though as the
876 // array collector will anyway operate on Object.
877 return varArg ? Object.class : double.class;
878 } else if (!clazz.isPrimitive() || clazz == long.class || clazz == char.class) {
879 return Object.class;
880 }
881 return clazz;
882 }
883
884 private static Class<?> getNashornReturnType(final Class<?> clazz) {
885 if (clazz == byte.class || clazz == short.class) {
886 return int.class;
887 } else if (clazz == float.class) {
888 return double.class;
889 } else if (clazz == void.class || clazz == char.class) {
890 return Object.class;
891 }
892 return clazz;
893 }
894
895
896 private void loadField(final InstructionAdapter mv, final String name, final String desc) {
897 if(classOverride) {
898 mv.getstatic(generatedClassName, name, desc);
899 } else {
900 mv.visitVarInsn(ALOAD, 0);
901 mv.getfield(generatedClassName, name, desc);
902 }
903 }
904
905 private static void convertReturnValue(final InstructionAdapter mv, final Class<?> origReturnType) {
906 if (origReturnType == void.class) {
907 mv.pop();
908 } else if (origReturnType == Object.class) {
909 // Must hide ConsString (and potentially other internal Nashorn types) from callers
910 EXPORT_RETURN_VALUE.invoke(mv);
911 } else if (origReturnType == byte.class) {
912 mv.visitInsn(I2B);
913 } else if (origReturnType == short.class) {
914 mv.visitInsn(I2S);
915 } else if (origReturnType == float.class) {
916 mv.visitInsn(D2F);
917 } else if (origReturnType == char.class) {
918 TO_CHAR_PRIMITIVE.invoke(mv);
919 }
920 }
921
922 /**
923 * Emits instruction for converting a parameter on the top of the stack to
924 * a type that is understood by Nashorn.
925 * @param mv the current method visitor
926 * @param t the type on the top of the stack
927 * @param varArg if the invocation will be variable arity
928 */
929 private static void convertParam(final InstructionAdapter mv, final Type t, final boolean varArg) {
930 // We perform conversions of some primitives to accommodate types that
931 // Nashorn can handle.
932 switch(t.getSort()) {
933 case Type.CHAR:
934 // Chars are boxed, as we don't know if the JS code wants to treat
935 // them as an effective "unsigned short" or as a single-char string.
936 CHAR_VALUE_OF.invoke(mv);
937 break;
938 case Type.FLOAT:
939 // Floats are widened to double.
940 mv.visitInsn(Opcodes.F2D);
941 if (varArg) {
942 // We'll be boxing everything anyway for the vararg invocation,
943 // so we might as well do it proactively here and thus not cause
944 // a widening in the number of slots, as that could even make
945 // the array creation invocation go over 255 param slots.
946 DOUBLE_VALUE_OF.invoke(mv);
947 }
948 break;
949 case Type.LONG:
950 // Longs are boxed as Nashorn can't represent them precisely as a
951 // primitive number.
952 LONG_VALUE_OF.invoke(mv);
953 break;
954 case Type.OBJECT:
955 if(t.equals(OBJECT_TYPE)) {
956 // Object can carry a ScriptObjectMirror and needs to be unwrapped
957 // before passing into a Nashorn function.
958 UNWRAP.invoke(mv);
959 }
960 break;
961 }
962 }
963
964 private static int getParamListLengthInSlots(final Type[] paramTypes) {
965 int len = paramTypes.length;
966 for(final Type t: paramTypes) {
967 final int sort = t.getSort();
968 if (sort == Type.FLOAT || sort == Type.DOUBLE) {
969 // Floats are widened to double, so they'll take up two slots.
970 // Longs on the other hand are always boxed, so their width
971 // becomes 1 and thus they don't contribute an extra slot here.
972 ++len;
973 }
974 }
975 return len;
976 }
977
978 /**
979 * Emit code to restore the previous Nashorn Context when needed.
980 * @param mv the instruction adapter
981 * @param globalRestoringRunnableVar index of the local variable holding the reference to the global restoring Runnable
982 */
983 private static void emitFinally(final InstructionAdapter mv, final int globalRestoringRunnableVar) {
984 mv.visitVarInsn(ALOAD, globalRestoringRunnableVar);
985 RUN.invoke(mv);
986 }
987
988 private static boolean isThrowableDeclared(final Class<?>[] exceptions) {
989 for (final Class<?> exception : exceptions) {
990 if (exception == Throwable.class) {
991 return true;
992 }
993 }
994 return false;
995 }
996
997 private void generateSuperMethods() {
998 for(final MethodInfo mi: methodInfos) {
999 if(!Modifier.isAbstract(mi.method.getModifiers())) {
1000 generateSuperMethod(mi);
1001 }
1002 }
1003 }
1004
1005 private void generateSuperMethod(final MethodInfo mi) {
1006 final Method method = mi.method;
1007
1008 final String methodDesc = mi.type.toMethodDescriptorString();
1009 final String name = mi.getName();
1010
1011 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(getAccessModifiers(method),
1012 SUPER_PREFIX + name, methodDesc, null, getExceptionNames(method.getExceptionTypes())));
1013 mv.visitCode();
1014
1015 emitSuperCall(mv, method.getDeclaringClass(), name, methodDesc);
1016 mv.areturn(Type.getType(mi.type.returnType()));
1017 endMethod(mv);
1018 }
1019
1020 // find the appropriate super type to use for invokespecial on the given interface
1021 private Class<?> findInvokespecialOwnerFor(final Class<?> cl) {
1022 assert Modifier.isInterface(cl.getModifiers()) : cl + " is not an interface";
1023
1024 if (cl.isAssignableFrom(superClass)) {
1025 return superClass;
1026 }
1027
1028 for (final Class<?> iface : interfaces) {
1029 if (cl.isAssignableFrom(iface)) {
1030 return iface;
1031 }
1032 }
1033
1034 // we better that interface that extends the given interface!
1035 throw new AssertionError("can't find the class/interface that extends " + cl);
1036 }
1037
1038 private int emitSuperConstructorCall(final InstructionAdapter mv, final String methodDesc) {
1039 return emitSuperCall(mv, null, INIT, methodDesc, true);
1040 }
1041
1042 private int emitSuperCall(final InstructionAdapter mv, final Class<?> owner, final String name, final String methodDesc) {
1043 return emitSuperCall(mv, owner, name, methodDesc, false);
1044 }
1045
1046 private int emitSuperCall(final InstructionAdapter mv, final Class<?> owner, final String name, final String methodDesc, final boolean constructor) {
1047 mv.visitVarInsn(ALOAD, 0);
1048 int nextParam = 1;
1049 final Type methodType = Type.getMethodType(methodDesc);
1050 for(final Type t: methodType.getArgumentTypes()) {
1051 mv.load(nextParam, t);
1052 nextParam += t.getSize();
1053 }
1054
1055 // default method - non-abstract, interface method
1056 if (!constructor && Modifier.isInterface(owner.getModifiers())) {
1057 // we should call default method on the immediate "super" type - not on (possibly)
1058 // the indirectly inherited interface class!
1059 final Class<?> superType = findInvokespecialOwnerFor(owner);
1060 mv.visitMethodInsn(INVOKESPECIAL, Type.getInternalName(superType), name, methodDesc,
1061 Modifier.isInterface(superType.getModifiers()));
1062 } else {
1063 mv.invokespecial(superClassName, name, methodDesc, false);
1064 }
1065 return nextParam;
1066 }
1067
1068 private void generateFinalizerMethods() {
1069 generateFinalizerDelegate();
1070 generateFinalizerOverride();
1071 }
1072
1073 private void generateFinalizerDelegate() {
1074 // Generate a delegate that will be invoked from the no-permission trampoline. Note it can be private, as we'll
1075 // refer to it with a MethodHandle constant pool entry in the overridden finalize() method (see
1076 // generateFinalizerOverride()).
1077 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PRIVATE | ACC_STATIC,
1078 FINALIZER_DELEGATE_NAME, FINALIZER_DELEGATE_METHOD_DESCRIPTOR, null, null));
1079
1080 // Simply invoke super.finalize()
1081 mv.visitVarInsn(ALOAD, 0);
1082 mv.checkcast(Type.getType(generatedClassName));
1083 mv.invokespecial(superClassName, "finalize", VOID_METHOD_DESCRIPTOR, false);
1084
1085 mv.visitInsn(RETURN);
1086 endMethod(mv);
1087 }
1088
1089 private void generateFinalizerOverride() {
1090 final InstructionAdapter mv = new InstructionAdapter(cw.visitMethod(ACC_PUBLIC, "finalize",
1091 VOID_METHOD_DESCRIPTOR, null, null));
1092 // Overridden finalizer will take a MethodHandle to the finalizer delegating method, ...
1093 mv.aconst(new Handle(Opcodes.H_INVOKESTATIC, generatedClassName, FINALIZER_DELEGATE_NAME,
1094 FINALIZER_DELEGATE_METHOD_DESCRIPTOR, false));
1095 mv.visitVarInsn(ALOAD, 0);
1096 // ...and invoke it through JavaAdapterServices.invokeNoPermissions
1097 INVOKE_NO_PERMISSIONS.invoke(mv);
1098 mv.visitInsn(RETURN);
1099 endMethod(mv);
1100 }
1101
1102 private static String[] getExceptionNames(final Class<?>[] exceptions) {
1103 final String[] exceptionNames = new String[exceptions.length];
1104 for (int i = 0; i < exceptions.length; ++i) {
1105 exceptionNames[i] = Type.getInternalName(exceptions[i]);
1106 }
1107 return exceptionNames;
1108 }
1109
1110 private static int getAccessModifiers(final Method method) {
1111 return ACC_PUBLIC | (method.isVarArgs() ? ACC_VARARGS : 0);
1112 }
1113
1114 /**
1115 * Gathers methods that can be implemented or overridden from the specified type into this factory's
1116 * {@link #methodInfos} set. It will add all non-final, non-static methods that are either public or protected from
1117 * the type if the type itself is public. If the type is a class, the method will recursively invoke itself for its
1118 * superclass and the interfaces it implements, and add further methods that were not directly declared on the
1119 * class.
1120 * @param type the type defining the methods.
1121 */
1122 private void gatherMethods(final Class<?> type) throws AdaptationException {
1123 if (Modifier.isPublic(type.getModifiers())) {
1124 final Method[] typeMethods = type.isInterface() ? type.getMethods() : type.getDeclaredMethods();
1125
1126 for (final Method typeMethod: typeMethods) {
1127 final String name = typeMethod.getName();
1128 if(name.startsWith(SUPER_PREFIX)) {
1129 continue;
1130 }
1131 final int m = typeMethod.getModifiers();
1132 if (Modifier.isStatic(m)) {
1133 continue;
1134 }
1135 if (Modifier.isPublic(m) || Modifier.isProtected(m)) {
1136 // Is it a "finalize()"?
1137 if(name.equals("finalize") && typeMethod.getParameterCount() == 0) {
1138 if(type != Object.class) {
1139 hasExplicitFinalizer = true;
1140 if(Modifier.isFinal(m)) {
1141 // Must be able to override an explicit finalizer
1142 throw new AdaptationException(Outcome.ERROR_FINAL_FINALIZER, type.getCanonicalName());
1143 }
1144 }
1145 continue;
1146 }
1147
1148 final MethodInfo mi = new MethodInfo(typeMethod);
1149 if (Modifier.isFinal(m) || isCallerSensitive(typeMethod)) {
1150 finalMethods.add(mi);
1151 } else if (!finalMethods.contains(mi) && methodInfos.add(mi) && Modifier.isAbstract(m)) {
1152 abstractMethodNames.add(mi.getName());
1153 }
1154 }
1155 }
1156 }
1157 // If the type is a class, visit its superclasses and declared interfaces. If it's an interface, we're done.
1158 // Needing to invoke the method recursively for a non-interface Class object is the consequence of needing to
1159 // see all declared protected methods, and Class.getDeclaredMethods() doesn't provide those declared in a
1160 // superclass. For interfaces, we used Class.getMethods(), as we're only interested in public ones there, and
1161 // getMethods() does provide those declared in a superinterface.
1162 if (!type.isInterface()) {
1163 final Class<?> superType = type.getSuperclass();
1164 if (superType != null) {
1165 gatherMethods(superType);
1166 }
1167 for (final Class<?> itf: type.getInterfaces()) {
1168 gatherMethods(itf);
1169 }
1170 }
1171 }
1172
1173 private void gatherMethods(final List<Class<?>> classes) throws AdaptationException {
1174 for(final Class<?> c: classes) {
1175 gatherMethods(c);
1176 }
1177 }
1178
1179 private static final AccessControlContext GET_DECLARED_MEMBERS_ACC_CTXT = ClassAndLoader.createPermAccCtxt("accessDeclaredMembers");
1180
1181 /**
1182 * Creates a collection of methods that are not final, but we still never allow them to be overridden in adapters,
1183 * as explicitly declaring them automatically is a bad idea. Currently, this means {@code Object.finalize()} and
1184 * {@code Object.clone()}.
1185 * @return a collection of method infos representing those methods that we never override in adapter classes.
1186 */
1187 private static Collection<MethodInfo> getExcludedMethods() {
1188 return AccessController.doPrivileged(new PrivilegedAction<Collection<MethodInfo>>() {
1189 @Override
1190 public Collection<MethodInfo> run() {
1191 try {
1192 return Arrays.asList(
1193 new MethodInfo(Object.class, "finalize"),
1194 new MethodInfo(Object.class, "clone"));
1195 } catch (final NoSuchMethodException e) {
1196 throw new AssertionError(e);
1197 }
1198 }
1199 }, GET_DECLARED_MEMBERS_ACC_CTXT);
1200 }
1201
1202 private String getCommonSuperClass(final String type1, final String type2) {
1203 try {
1204 final Class<?> c1 = Class.forName(type1.replace('/', '.'), false, commonLoader);
1205 final Class<?> c2 = Class.forName(type2.replace('/', '.'), false, commonLoader);
1206 if (c1.isAssignableFrom(c2)) {
1207 return type1;
1208 }
1209 if (c2.isAssignableFrom(c1)) {
1210 return type2;
1211 }
1212 if (c1.isInterface() || c2.isInterface()) {
1213 return OBJECT_TYPE.getInternalName();
1214 }
1215 return assignableSuperClass(c1, c2).getName().replace('.', '/');
1216 } catch(final ClassNotFoundException e) {
1217 throw new RuntimeException(e);
1218 }
1219 }
1220
1221 private static Class<?> assignableSuperClass(final Class<?> c1, final Class<?> c2) {
1222 final Class<?> superClass = c1.getSuperclass();
1223 return superClass.isAssignableFrom(c2) ? superClass : assignableSuperClass(superClass, c2);
1224 }
1225
1226 private static boolean isCallerSensitive(final AccessibleObject e) {
1227 return e.isAnnotationPresent(CallerSensitive.class);
1228 }
1229
1230 private static Call lookupServiceMethod(final String name, final Class<?> rtype, final Class<?>... ptypes) {
1231 return staticCallNoLookup(JavaAdapterServices.class, name, rtype, ptypes);
1232 }
1233 }