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 quotableOpField; // A getter method handle that is used to retrieve the
73 // string representation of the quotable lambda's associated
74 // intermediate representation (can be null).
75 final MethodHandleInfo quotableOpFieldInfo; // Info about the quotable getter method handle (can be null).
76
77 /**
78 * Meta-factory constructor.
79 *
80 * @param caller Stacked automatically by VM; represents a lookup context
81 * with the accessibility privileges of the caller.
82 * @param factoryType Stacked automatically by VM; the signature of the
83 * invoked method, which includes the expected static
84 * type of the returned lambda object, and the static
85 * types of the captured arguments for the lambda. In
86 * the event that the implementation method is an
87 * instance method, the first argument in the invocation
88 * signature will correspond to the receiver.
89 * @param interfaceMethodName Name of the method in the functional interface to
90 * which the lambda or method reference is being
91 * converted, represented as a String.
92 * @param interfaceMethodType Type of the method in the functional interface to
93 * which the lambda or method reference is being
94 * converted, represented as a MethodType.
95 * @param implementation The implementation method which should be called
96 * (with suitable adaptation of argument types, return
97 * types, and adjustment for captured arguments) when
98 * methods of the resulting functional interface instance
99 * are invoked.
100 * @param dynamicMethodType The signature of the primary functional
101 * interface method after type variables are
102 * substituted with their instantiation from
103 * the capture site
104 * @param isSerializable Should the lambda be made serializable? If set,
105 * either the target type or one of the additional SAM
106 * types must extend {@code Serializable}.
107 * @param altInterfaces Additional interfaces which the lambda object
108 * should implement.
109 * @param altMethods Method types for additional signatures to be
110 * implemented by invoking the implementation method
111 * @param reflectiveField a {@linkplain MethodHandles.Lookup#findGetter(Class, String, Class) getter}
112 * method handle that is used to retrieve the string representation of the
113 * quotable lambda's associated intermediate representation.
114 * @throws LambdaConversionException If any of the meta-factory protocol
115 * invariants are violated
116 * @throws SecurityException If a security manager is present, and it
117 * <a href="MethodHandles.Lookup.html#secmgr">denies access</a>
118 * from {@code caller} to the package of {@code implementation}.
119 */
120 AbstractValidatingLambdaMetafactory(MethodHandles.Lookup caller,
121 MethodType factoryType,
122 String interfaceMethodName,
123 MethodType interfaceMethodType,
124 MethodHandle implementation,
125 MethodType dynamicMethodType,
126 boolean isSerializable,
127 Class<?>[] altInterfaces,
128 MethodType[] altMethods,
129 MethodHandle reflectiveField)
130 throws LambdaConversionException {
131 if (!caller.hasFullPrivilegeAccess()) {
132 throw new LambdaConversionException(String.format(
133 "Invalid caller: %s",
134 caller.lookupClass().getName()));
135 }
136 this.caller = caller;
137 this.targetClass = caller.lookupClass();
138 this.factoryType = factoryType;
139
140 this.interfaceClass = factoryType.returnType();
141
142 this.interfaceMethodName = interfaceMethodName;
143 this.interfaceMethodType = interfaceMethodType;
144
145 this.implementation = implementation;
146 this.implMethodType = implementation.type();
147 try {
148 this.implInfo = caller.revealDirect(implementation); // may throw SecurityException
149 } catch (IllegalArgumentException e) {
150 throw new LambdaConversionException(implementation + " is not direct or cannot be cracked");
151 }
152 switch (implInfo.getReferenceKind()) {
153 case REF_invokeVirtual:
154 case REF_invokeInterface:
155 this.implClass = implMethodType.parameterType(0);
156 // reference kind reported by implInfo may not match implMethodType's first param
157 // Example: implMethodType is (Cloneable)String, implInfo is for Object.toString
158 this.implKind = implClass.isInterface() ? REF_invokeInterface : REF_invokeVirtual;
159 this.implIsInstanceMethod = true;
160 break;
161 case REF_invokeSpecial:
162 // JDK-8172817: should use referenced class here, but we don't know what it was
163 this.implClass = implInfo.getDeclaringClass();
164 this.implIsInstanceMethod = true;
165
166 // Classes compiled prior to dynamic nestmate support invoke a private instance
167 // method with REF_invokeSpecial. Newer classes use REF_invokeVirtual or
168 // REF_invokeInterface, and we can use that instruction in the lambda class.
169 if (targetClass == implClass && Modifier.isPrivate(implInfo.getModifiers())) {
170 this.implKind = implClass.isInterface() ? REF_invokeInterface : REF_invokeVirtual;
171 } else {
172 this.implKind = REF_invokeSpecial;
173 }
174 break;
175 case REF_invokeStatic:
176 case REF_newInvokeSpecial:
177 // JDK-8172817: should use referenced class here for invokestatic, but we don't know what it was
178 this.implClass = implInfo.getDeclaringClass();
179 this.implKind = implInfo.getReferenceKind();
180 this.implIsInstanceMethod = false;
181 break;
182 default:
183 throw new LambdaConversionException(String.format("Unsupported MethodHandle kind: %s", implInfo));
184 }
185
186 this.dynamicMethodType = dynamicMethodType;
187 this.isSerializable = isSerializable;
188 this.altInterfaces = altInterfaces;
189 this.altMethods = altMethods;
190 this.quotableOpField = reflectiveField;
191
192 if (interfaceMethodName.isEmpty() ||
193 interfaceMethodName.indexOf('.') >= 0 ||
194 interfaceMethodName.indexOf(';') >= 0 ||
195 interfaceMethodName.indexOf('[') >= 0 ||
196 interfaceMethodName.indexOf('/') >= 0 ||
197 interfaceMethodName.indexOf('<') >= 0 ||
198 interfaceMethodName.indexOf('>') >= 0) {
199 throw new LambdaConversionException(String.format(
200 "Method name '%s' is not legal",
201 interfaceMethodName));
202 }
203
204 if (!interfaceClass.isInterface()) {
205 throw new LambdaConversionException(String.format(
206 "%s is not an interface",
207 interfaceClass.getName()));
208 }
209
210 for (Class<?> c : altInterfaces) {
211 if (!c.isInterface()) {
212 throw new LambdaConversionException(String.format(
213 "%s is not an interface",
214 c.getName()));
215 }
216 }
217
218 if (reflectiveField != null) {
219 try {
220 quotableOpFieldInfo = caller.revealDirect(reflectiveField); // may throw SecurityException
221 } catch (IllegalArgumentException e) {
222 throw new LambdaConversionException(implementation + " is not direct or cannot be cracked");
223 }
224 if (quotableOpFieldInfo.getReferenceKind() != REF_getField &&
225 quotableOpFieldInfo.getReferenceKind() != REF_getStatic) {
226 throw new LambdaConversionException(String.format("Unsupported MethodHandle kind: %s", quotableOpFieldInfo));
227 }
228 } else {
229 quotableOpFieldInfo = null;
230 }
231 }
232
233 /**
234 * Build the CallSite.
235 *
236 * @return a CallSite, which, when invoked, will return an instance of the
237 * functional interface
238 * @throws LambdaConversionException
239 */
240 abstract CallSite buildCallSite()
241 throws LambdaConversionException;
242
243 /**
244 * Check the meta-factory arguments for errors
245 * @throws LambdaConversionException if there are improper conversions
246 */
247 void validateMetafactoryArgs() throws LambdaConversionException {
248 // Check arity: captured + SAM == impl
249 final int implArity = implMethodType.parameterCount();
250 final int capturedArity = factoryType.parameterCount();
251 final int samArity = interfaceMethodType.parameterCount();
252 final int dynamicArity = dynamicMethodType.parameterCount();
253 if (implArity != capturedArity + samArity) {
254 throw new LambdaConversionException(
255 String.format("Incorrect number of parameters for %s method %s; %d captured parameters, %d functional interface method parameters, %d implementation parameters",
256 implIsInstanceMethod ? "instance" : "static", implInfo,
257 capturedArity, samArity, implArity));
258 }
259 if (dynamicArity != samArity) {
260 throw new LambdaConversionException(
261 String.format("Incorrect number of parameters for %s method %s; %d dynamic parameters, %d functional interface method parameters",
262 implIsInstanceMethod ? "instance" : "static", implInfo,
263 dynamicArity, samArity));
264 }
265 for (MethodType bridgeMT : altMethods) {
266 if (bridgeMT.parameterCount() != samArity) {
267 throw new LambdaConversionException(
268 String.format("Incorrect number of parameters for bridge signature %s; incompatible with %s",
269 bridgeMT, interfaceMethodType));
270 }
271 }
272
273 // If instance: first captured arg (receiver) must be subtype of class where impl method is defined
274 final int capturedStart; // index of first non-receiver capture parameter in implMethodType
275 final int samStart; // index of first non-receiver sam parameter in implMethodType
276 if (implIsInstanceMethod) {
277 final Class<?> receiverClass;
278
279 // implementation is an instance method, adjust for receiver in captured variables / SAM arguments
280 if (capturedArity == 0) {
281 // receiver is function parameter
282 capturedStart = 0;
283 samStart = 1;
284 receiverClass = dynamicMethodType.parameterType(0);
285 } else {
286 // receiver is a captured variable
287 capturedStart = 1;
288 samStart = capturedArity;
289 receiverClass = factoryType.parameterType(0);
290 }
291
292 // check receiver type
293 if (!implClass.isAssignableFrom(receiverClass)) {
294 throw new LambdaConversionException(
295 String.format("Invalid receiver type %s; not a subtype of implementation type %s",
296 receiverClass, implClass));
297 }
298 } else {
299 // no receiver
300 capturedStart = 0;
301 samStart = capturedArity;
302 }
303
304 // Check for exact match on non-receiver captured arguments
305 for (int i=capturedStart; i<capturedArity; i++) {
306 Class<?> implParamType = implMethodType.parameterType(i);
307 Class<?> capturedParamType = factoryType.parameterType(i);
308 if (!capturedParamType.equals(implParamType)) {
309 throw new LambdaConversionException(
310 String.format("Type mismatch in captured lambda parameter %d: expecting %s, found %s",
311 i, capturedParamType, implParamType));
312 }
313 }
314 // Check for adaptation match on non-receiver SAM arguments
315 for (int i=samStart; i<implArity; i++) {
316 Class<?> implParamType = implMethodType.parameterType(i);
317 Class<?> dynamicParamType = dynamicMethodType.parameterType(i - capturedArity);
318 if (!isAdaptableTo(dynamicParamType, implParamType, true)) {
319 throw new LambdaConversionException(
320 String.format("Type mismatch for lambda argument %d: %s is not convertible to %s",
321 i, dynamicParamType, implParamType));
322 }
323 }
324
325 // Adaptation match: return type
326 Class<?> expectedType = dynamicMethodType.returnType();
327 Class<?> actualReturnType = implMethodType.returnType();
328 if (!isAdaptableToAsReturn(actualReturnType, expectedType)) {
329 throw new LambdaConversionException(
330 String.format("Type mismatch for lambda return: %s is not convertible to %s",
331 actualReturnType, expectedType));
332 }
333
334 // Check descriptors of generated methods
335 checkDescriptor(interfaceMethodType);
336 for (MethodType bridgeMT : altMethods) {
337 checkDescriptor(bridgeMT);
338 }
339 }
340
341 /** Validate that the given descriptor's types are compatible with {@code dynamicMethodType} **/
342 private void checkDescriptor(MethodType descriptor) throws LambdaConversionException {
343 for (int i = 0; i < dynamicMethodType.parameterCount(); i++) {
344 Class<?> dynamicParamType = dynamicMethodType.parameterType(i);
345 Class<?> descriptorParamType = descriptor.parameterType(i);
346 if (!descriptorParamType.isAssignableFrom(dynamicParamType)) {
347 String msg = String.format("Type mismatch for dynamic parameter %d: %s is not a subtype of %s",
348 i, dynamicParamType, descriptorParamType);
349 throw new LambdaConversionException(msg);
350 }
351 }
352
353 Class<?> dynamicReturnType = dynamicMethodType.returnType();
354 Class<?> descriptorReturnType = descriptor.returnType();
355 if (!isAdaptableToAsReturnStrict(dynamicReturnType, descriptorReturnType)) {
356 String msg = String.format("Type mismatch for lambda expected return: %s is not convertible to %s",
357 dynamicReturnType, descriptorReturnType);
358 throw new LambdaConversionException(msg);
359 }
360 }
361
362 /**
363 * Check type adaptability for parameter types.
364 * @param fromType Type to convert from
365 * @param toType Type to convert to
366 * @param strict If true, do strict checks, else allow that fromType may be parameterized
367 * @return True if 'fromType' can be passed to an argument of 'toType'
368 */
369 private boolean isAdaptableTo(Class<?> fromType, Class<?> toType, boolean strict) {
370 if (fromType.equals(toType)) {
371 return true;
372 }
373 if (fromType.isPrimitive()) {
374 Wrapper wfrom = forPrimitiveType(fromType);
375 if (toType.isPrimitive()) {
376 // both are primitive: widening
377 Wrapper wto = forPrimitiveType(toType);
378 return wto.isConvertibleFrom(wfrom);
379 } else {
380 // from primitive to reference: boxing
381 return toType.isAssignableFrom(wfrom.wrapperType());
382 }
383 } else {
384 if (toType.isPrimitive()) {
385 // from reference to primitive: unboxing
386 Wrapper wfrom;
387 if (isWrapperType(fromType) && (wfrom = forWrapperType(fromType)).primitiveType().isPrimitive()) {
388 // fromType is a primitive wrapper; unbox+widen
389 Wrapper wto = forPrimitiveType(toType);
390 return wto.isConvertibleFrom(wfrom);
391 } else {
392 // must be convertible to primitive
393 return !strict;
394 }
395 } else {
396 // both are reference types: fromType should be a superclass of toType.
397 return !strict || toType.isAssignableFrom(fromType);
398 }
399 }
400 }
401
402 /**
403 * Check type adaptability for return types --
404 * special handling of void type) and parameterized fromType
405 * @return True if 'fromType' can be converted to 'toType'
406 */
407 private boolean isAdaptableToAsReturn(Class<?> fromType, Class<?> toType) {
408 return toType.equals(void.class)
409 || !fromType.equals(void.class) && isAdaptableTo(fromType, toType, false);
410 }
411 private boolean isAdaptableToAsReturnStrict(Class<?> fromType, Class<?> toType) {
412 if (fromType.equals(void.class) || toType.equals(void.class)) return fromType.equals(toType);
413 else return isAdaptableTo(fromType, toType, true);
414 }
415
416
417 /*********** Logging support -- for debugging only, uncomment as needed
418 static final Executor logPool = Executors.newSingleThreadExecutor();
419 protected static void log(final String s) {
420 MethodHandleProxyLambdaMetafactory.logPool.execute(new Runnable() {
421 @Override
422 public void run() {
423 System.out.println(s);
424 }
425 });
426 }
427
428 protected static void log(final String s, final Throwable e) {
429 MethodHandleProxyLambdaMetafactory.logPool.execute(new Runnable() {
430 @Override
431 public void run() {
432 System.out.println(s);
433 e.printStackTrace(System.out);
434 }
435 });
436 }
437 ***********************/
438
439 }