1 /*
2 * Copyright (c) 2012, 2024, 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 package java.lang.invoke;
26
27 import sun.invoke.util.Wrapper;
28
29 import java.lang.reflect.Modifier;
30
31 import static java.lang.invoke.MethodHandleInfo.*;
32 import static sun.invoke.util.Wrapper.forPrimitiveType;
33 import static sun.invoke.util.Wrapper.forWrapperType;
34 import static sun.invoke.util.Wrapper.isWrapperType;
35
36 /**
37 * Abstract implementation of a lambda metafactory which provides parameter
38 * unrolling and input validation.
39 *
40 * @see LambdaMetafactory
41 */
42 /* package */ abstract class AbstractValidatingLambdaMetafactory {
43
44 /*
45 * For context, the comments for the following fields are marked in quotes
46 * with their values, given this program:
47 * interface II<T> { Object foo(T x); }
48 * interface JJ<R extends Number> extends II<R> { }
49 * class CC { String impl(int i) { return "impl:"+i; }}
50 * class X {
51 * public static void main(String[] args) {
52 * JJ<Integer> iii = (new CC())::impl;
53 * System.out.printf(">>> %s\n", iii.foo(44));
54 * }}
55 */
56 final MethodHandles.Lookup caller; // The caller's lookup context
57 final Class<?> targetClass; // The class calling the meta-factory via invokedynamic "class X"
58 final MethodType factoryType; // The type of the invoked method "(CC)II"
59 final Class<?> interfaceClass; // The type of the returned instance "interface JJ"
60 final String interfaceMethodName; // Name of the method to implement "foo"
61 final MethodType interfaceMethodType; // Type of the method to implement "(Object)Object"
62 final MethodHandle implementation; // Raw method handle for the implementation method
63 final MethodType implMethodType; // Type of the implementation MethodHandle "(CC,int)String"
64 final MethodHandleInfo implInfo; // Info about the implementation method handle "MethodHandleInfo[5 CC.impl(int)String]"
65 final int implKind; // Invocation kind for implementation "5"=invokevirtual
66 final boolean implIsInstanceMethod; // Is the implementation an instance method "true"
67 final Class<?> implClass; // Class for referencing the implementation method "class CC"
68 final MethodType dynamicMethodType; // Dynamically checked method type "(Integer)Object"
69 final boolean isSerializable; // Should the returned instance be serializable
70 final Class<?>[] altInterfaces; // Additional interfaces to be implemented
71 final MethodType[] altMethods; // Signatures of additional methods to bridge
72 final MethodHandle quotableOpGetter; // A getter method handle that is used to retrieve the
73 // the quotable lambda's associated intermediate representation (can be null).
74 final MethodHandleInfo quotableOpGetterInfo; // Info about the quotable getter method handle (can be null).
75
76 /**
77 * Meta-factory constructor.
78 *
79 * @param caller Stacked automatically by VM; represents a lookup context
80 * with the accessibility privileges of the caller.
81 * @param factoryType Stacked automatically by VM; the signature of the
82 * invoked method, which includes the expected static
83 * type of the returned lambda object, and the static
84 * types of the captured arguments for the lambda. In
85 * the event that the implementation method is an
86 * instance method, the first argument in the invocation
87 * signature will correspond to the receiver.
88 * @param interfaceMethodName Name of the method in the functional interface to
89 * which the lambda or method reference is being
90 * converted, represented as a String.
91 * @param interfaceMethodType Type of the method in the functional interface to
92 * which the lambda or method reference is being
93 * converted, represented as a MethodType.
94 * @param implementation The implementation method which should be called
95 * (with suitable adaptation of argument types, return
96 * types, and adjustment for captured arguments) when
97 * methods of the resulting functional interface instance
98 * are invoked.
99 * @param dynamicMethodType The signature of the primary functional
100 * interface method after type variables are
101 * substituted with their instantiation from
102 * the capture site
103 * @param isSerializable Should the lambda be made serializable? If set,
104 * either the target type or one of the additional SAM
105 * types must extend {@code Serializable}.
106 * @param altInterfaces Additional interfaces which the lambda object
107 * should implement.
108 * @param altMethods Method types for additional signatures to be
109 * implemented by invoking the implementation method
110 * @param reflectiveField a {@linkplain MethodHandles.Lookup#findGetter(Class, String, Class) getter}
111 * method handle that is used to retrieve the string representation of the
112 * quotable lambda's associated intermediate representation.
113 * @throws LambdaConversionException If any of the meta-factory protocol
114 * invariants are violated
115 */
116 AbstractValidatingLambdaMetafactory(MethodHandles.Lookup caller,
117 MethodType factoryType,
118 String interfaceMethodName,
119 MethodType interfaceMethodType,
120 MethodHandle implementation,
121 MethodType dynamicMethodType,
122 boolean isSerializable,
123 Class<?>[] altInterfaces,
124 MethodType[] altMethods,
125 MethodHandle reflectiveField)
126 throws LambdaConversionException {
127 if (!caller.hasFullPrivilegeAccess()) {
128 throw new LambdaConversionException(String.format(
129 "Invalid caller: %s",
130 caller.lookupClass().getName()));
131 }
132 this.caller = caller;
133 this.targetClass = caller.lookupClass();
134 this.factoryType = factoryType;
135
136 this.interfaceClass = factoryType.returnType();
137
138 this.interfaceMethodName = interfaceMethodName;
139 this.interfaceMethodType = interfaceMethodType;
140
141 this.implementation = implementation;
142 this.implMethodType = implementation.type();
143 try {
144 this.implInfo = caller.revealDirect(implementation);
145 } catch (IllegalArgumentException e) {
146 throw new LambdaConversionException(implementation + " is not direct or cannot be cracked");
147 }
148 switch (implInfo.getReferenceKind()) {
149 case REF_invokeVirtual:
150 case REF_invokeInterface:
151 this.implClass = implMethodType.parameterType(0);
152 // reference kind reported by implInfo may not match implMethodType's first param
153 // Example: implMethodType is (Cloneable)String, implInfo is for Object.toString
154 this.implKind = implClass.isInterface() ? REF_invokeInterface : REF_invokeVirtual;
155 this.implIsInstanceMethod = true;
156 break;
157 case REF_invokeSpecial:
158 // JDK-8172817: should use referenced class here, but we don't know what it was
159 this.implClass = implInfo.getDeclaringClass();
160 this.implIsInstanceMethod = true;
161
162 // Classes compiled prior to dynamic nestmate support invoke a private instance
163 // method with REF_invokeSpecial. Newer classes use REF_invokeVirtual or
164 // REF_invokeInterface, and we can use that instruction in the lambda class.
165 if (targetClass == implClass && Modifier.isPrivate(implInfo.getModifiers())) {
166 this.implKind = implClass.isInterface() ? REF_invokeInterface : REF_invokeVirtual;
167 } else {
168 this.implKind = REF_invokeSpecial;
169 }
170 break;
171 case REF_invokeStatic:
172 case REF_newInvokeSpecial:
173 // JDK-8172817: should use referenced class here for invokestatic, but we don't know what it was
174 this.implClass = implInfo.getDeclaringClass();
175 this.implKind = implInfo.getReferenceKind();
176 this.implIsInstanceMethod = false;
177 break;
178 default:
179 throw new LambdaConversionException(String.format("Unsupported MethodHandle kind: %s", implInfo));
180 }
181
182 this.dynamicMethodType = dynamicMethodType;
183 this.isSerializable = isSerializable;
184 this.altInterfaces = altInterfaces;
185 this.altMethods = altMethods;
186 this.quotableOpGetter = reflectiveField;
187
188 if (interfaceMethodName.isEmpty() ||
189 interfaceMethodName.indexOf('.') >= 0 ||
190 interfaceMethodName.indexOf(';') >= 0 ||
191 interfaceMethodName.indexOf('[') >= 0 ||
192 interfaceMethodName.indexOf('/') >= 0 ||
193 interfaceMethodName.indexOf('<') >= 0 ||
194 interfaceMethodName.indexOf('>') >= 0) {
195 throw new LambdaConversionException(String.format(
196 "Method name '%s' is not legal",
197 interfaceMethodName));
198 }
199
200 if (!interfaceClass.isInterface()) {
201 throw new LambdaConversionException(String.format(
202 "%s is not an interface",
203 interfaceClass.getName()));
204 }
205
206 for (Class<?> c : altInterfaces) {
207 if (!c.isInterface()) {
208 throw new LambdaConversionException(String.format(
209 "%s is not an interface",
210 c.getName()));
211 }
212 }
213
214 if (reflectiveField != null) {
215 try {
216 quotableOpGetterInfo = caller.revealDirect(reflectiveField); // may throw SecurityException
217 } catch (IllegalArgumentException e) {
218 throw new LambdaConversionException(implementation + " is not direct or cannot be cracked");
219 }
220 if (quotableOpGetterInfo.getReferenceKind() != REF_invokeStatic) {
221 throw new LambdaConversionException(String.format("Unsupported MethodHandle kind: %s", quotableOpGetterInfo));
222 }
223 } else {
224 quotableOpGetterInfo = null;
225 }
226 }
227
228 /**
229 * Build the CallSite.
230 *
231 * @return a CallSite, which, when invoked, will return an instance of the
232 * functional interface
233 * @throws LambdaConversionException
234 */
235 abstract CallSite buildCallSite()
236 throws LambdaConversionException;
237
238 /**
239 * Check the meta-factory arguments for errors
240 * @throws LambdaConversionException if there are improper conversions
241 */
242 void validateMetafactoryArgs() throws LambdaConversionException {
243 // Check arity: captured + SAM == impl
244 final int implArity = implMethodType.parameterCount();
245 final int capturedArity = factoryType.parameterCount();
246 final int samArity = interfaceMethodType.parameterCount();
247 final int dynamicArity = dynamicMethodType.parameterCount();
248 if (implArity != capturedArity + samArity) {
249 throw new LambdaConversionException(
250 String.format("Incorrect number of parameters for %s method %s; %d captured parameters, %d functional interface method parameters, %d implementation parameters",
251 implIsInstanceMethod ? "instance" : "static", implInfo,
252 capturedArity, samArity, implArity));
253 }
254 if (dynamicArity != samArity) {
255 throw new LambdaConversionException(
256 String.format("Incorrect number of parameters for %s method %s; %d dynamic parameters, %d functional interface method parameters",
257 implIsInstanceMethod ? "instance" : "static", implInfo,
258 dynamicArity, samArity));
259 }
260 for (MethodType bridgeMT : altMethods) {
261 if (bridgeMT.parameterCount() != samArity) {
262 throw new LambdaConversionException(
263 String.format("Incorrect number of parameters for bridge signature %s; incompatible with %s",
264 bridgeMT, interfaceMethodType));
265 }
266 }
267
268 // If instance: first captured arg (receiver) must be subtype of class where impl method is defined
269 final int capturedStart; // index of first non-receiver capture parameter in implMethodType
270 final int samStart; // index of first non-receiver sam parameter in implMethodType
271 if (implIsInstanceMethod) {
272 final Class<?> receiverClass;
273
274 // implementation is an instance method, adjust for receiver in captured variables / SAM arguments
275 if (capturedArity == 0) {
276 // receiver is function parameter
277 capturedStart = 0;
278 samStart = 1;
279 receiverClass = dynamicMethodType.parameterType(0);
280 } else {
281 // receiver is a captured variable
282 capturedStart = 1;
283 samStart = capturedArity;
284 receiverClass = factoryType.parameterType(0);
285 }
286
287 // check receiver type
288 if (!implClass.isAssignableFrom(receiverClass)) {
289 throw new LambdaConversionException(
290 String.format("Invalid receiver type %s; not a subtype of implementation type %s",
291 receiverClass, implClass));
292 }
293 } else {
294 // no receiver
295 capturedStart = 0;
296 samStart = capturedArity;
297 }
298
299 // Check for exact match on non-receiver captured arguments
300 for (int i=capturedStart; i<capturedArity; i++) {
301 Class<?> implParamType = implMethodType.parameterType(i);
302 Class<?> capturedParamType = factoryType.parameterType(i);
303 if (!capturedParamType.equals(implParamType)) {
304 throw new LambdaConversionException(
305 String.format("Type mismatch in captured lambda parameter %d: expecting %s, found %s",
306 i, capturedParamType, implParamType));
307 }
308 }
309 // Check for adaptation match on non-receiver SAM arguments
310 for (int i=samStart; i<implArity; i++) {
311 Class<?> implParamType = implMethodType.parameterType(i);
312 Class<?> dynamicParamType = dynamicMethodType.parameterType(i - capturedArity);
313 if (!isAdaptableTo(dynamicParamType, implParamType, true)) {
314 throw new LambdaConversionException(
315 String.format("Type mismatch for lambda argument %d: %s is not convertible to %s",
316 i, dynamicParamType, implParamType));
317 }
318 }
319
320 // Adaptation match: return type
321 Class<?> expectedType = dynamicMethodType.returnType();
322 Class<?> actualReturnType = implMethodType.returnType();
323 if (!isAdaptableToAsReturn(actualReturnType, expectedType)) {
324 throw new LambdaConversionException(
325 String.format("Type mismatch for lambda return: %s is not convertible to %s",
326 actualReturnType, expectedType));
327 }
328
329 // Check descriptors of generated methods
330 checkDescriptor(interfaceMethodType);
331 for (MethodType bridgeMT : altMethods) {
332 checkDescriptor(bridgeMT);
333 }
334 }
335
336 /** Validate that the given descriptor's types are compatible with {@code dynamicMethodType} **/
337 private void checkDescriptor(MethodType descriptor) throws LambdaConversionException {
338 for (int i = 0; i < dynamicMethodType.parameterCount(); i++) {
339 Class<?> dynamicParamType = dynamicMethodType.parameterType(i);
340 Class<?> descriptorParamType = descriptor.parameterType(i);
341 if (!descriptorParamType.isAssignableFrom(dynamicParamType)) {
342 String msg = String.format("Type mismatch for dynamic parameter %d: %s is not a subtype of %s",
343 i, dynamicParamType, descriptorParamType);
344 throw new LambdaConversionException(msg);
345 }
346 }
347
348 Class<?> dynamicReturnType = dynamicMethodType.returnType();
349 Class<?> descriptorReturnType = descriptor.returnType();
350 if (!isAdaptableToAsReturnStrict(dynamicReturnType, descriptorReturnType)) {
351 String msg = String.format("Type mismatch for lambda expected return: %s is not convertible to %s",
352 dynamicReturnType, descriptorReturnType);
353 throw new LambdaConversionException(msg);
354 }
355 }
356
357 /**
358 * Check type adaptability for parameter types.
359 * @param fromType Type to convert from
360 * @param toType Type to convert to
361 * @param strict If true, do strict checks, else allow that fromType may be parameterized
362 * @return True if 'fromType' can be passed to an argument of 'toType'
363 */
364 private boolean isAdaptableTo(Class<?> fromType, Class<?> toType, boolean strict) {
365 if (fromType.equals(toType)) {
366 return true;
367 }
368 if (fromType.isPrimitive()) {
369 Wrapper wfrom = forPrimitiveType(fromType);
370 if (toType.isPrimitive()) {
371 // both are primitive: widening
372 Wrapper wto = forPrimitiveType(toType);
373 return wto.isConvertibleFrom(wfrom);
374 } else {
375 // from primitive to reference: boxing
376 return toType.isAssignableFrom(wfrom.wrapperType());
377 }
378 } else {
379 if (toType.isPrimitive()) {
380 // from reference to primitive: unboxing
381 Wrapper wfrom;
382 if (isWrapperType(fromType) && (wfrom = forWrapperType(fromType)).primitiveType().isPrimitive()) {
383 // fromType is a primitive wrapper; unbox+widen
384 Wrapper wto = forPrimitiveType(toType);
385 return wto.isConvertibleFrom(wfrom);
386 } else {
387 // must be convertible to primitive
388 return !strict;
389 }
390 } else {
391 // both are reference types: fromType should be a superclass of toType.
392 return !strict || toType.isAssignableFrom(fromType);
393 }
394 }
395 }
396
397 /**
398 * Check type adaptability for return types --
399 * special handling of void type) and parameterized fromType
400 * @return True if 'fromType' can be converted to 'toType'
401 */
402 private boolean isAdaptableToAsReturn(Class<?> fromType, Class<?> toType) {
403 return toType.equals(void.class)
404 || !fromType.equals(void.class) && isAdaptableTo(fromType, toType, false);
405 }
406 private boolean isAdaptableToAsReturnStrict(Class<?> fromType, Class<?> toType) {
407 if (fromType.equals(void.class) || toType.equals(void.class)) return fromType.equals(toType);
408 else return isAdaptableTo(fromType, toType, true);
409 }
410
411
412 /*********** Logging support -- for debugging only, uncomment as needed
413 static final Executor logPool = Executors.newSingleThreadExecutor();
414 protected static void log(final String s) {
415 MethodHandleProxyLambdaMetafactory.logPool.execute(new Runnable() {
416 @Override
417 public void run() {
418 System.out.println(s);
419 }
420 });
421 }
422
423 protected static void log(final String s, final Throwable e) {
424 MethodHandleProxyLambdaMetafactory.logPool.execute(new Runnable() {
425 @Override
426 public void run() {
427 System.out.println(s);
428 e.printStackTrace(System.out);
429 }
430 });
431 }
432 ***********************/
433
434 }