1 /*
2 * Copyright (c) 2012, 2021, 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
73
74 /**
75 * Meta-factory constructor.
76 *
77 * @param caller Stacked automatically by VM; represents a lookup context
78 * with the accessibility privileges of the caller.
79 * @param factoryType Stacked automatically by VM; the signature of the
80 * invoked method, which includes the expected static
81 * type of the returned lambda object, and the static
82 * types of the captured arguments for the lambda. In
83 * the event that the implementation method is an
84 * instance method, the first argument in the invocation
85 * signature will correspond to the receiver.
86 * @param interfaceMethodName Name of the method in the functional interface to
87 * which the lambda or method reference is being
88 * converted, represented as a String.
89 * @param interfaceMethodType Type of the method in the functional interface to
90 * which the lambda or method reference is being
91 * converted, represented as a MethodType.
92 * @param implementation The implementation method which should be called
93 * (with suitable adaptation of argument types, return
94 * types, and adjustment for captured arguments) when
95 * methods of the resulting functional interface instance
96 * are invoked.
97 * @param dynamicMethodType The signature of the primary functional
98 * interface method after type variables are
99 * substituted with their instantiation from
100 * the capture site
101 * @param isSerializable Should the lambda be made serializable? If set,
102 * either the target type or one of the additional SAM
103 * types must extend {@code Serializable}.
104 * @param altInterfaces Additional interfaces which the lambda object
105 * should implement.
106 * @param altMethods Method types for additional signatures to be
107 * implemented by invoking the implementation method
108 * @throws LambdaConversionException If any of the meta-factory protocol
109 * invariants are violated
110 * @throws SecurityException If a security manager is present, and it
111 * <a href="MethodHandles.Lookup.html#secmgr">denies access</a>
112 * from {@code caller} to the package of {@code implementation}.
113 */
114 AbstractValidatingLambdaMetafactory(MethodHandles.Lookup caller,
115 MethodType factoryType,
116 String interfaceMethodName,
117 MethodType interfaceMethodType,
118 MethodHandle implementation,
119 MethodType dynamicMethodType,
120 boolean isSerializable,
121 Class<?>[] altInterfaces,
122 MethodType[] altMethods)
123 throws LambdaConversionException {
124 if (!caller.hasFullPrivilegeAccess()) {
125 throw new LambdaConversionException(String.format(
126 "Invalid caller: %s",
127 caller.lookupClass().getName()));
128 }
129 this.caller = caller;
130 this.targetClass = caller.lookupClass();
131 this.factoryType = factoryType;
132
133 this.interfaceClass = factoryType.returnType();
134
135 this.interfaceMethodName = interfaceMethodName;
136 this.interfaceMethodType = interfaceMethodType;
137
138 this.implementation = implementation;
139 this.implMethodType = implementation.type();
140 try {
141 this.implInfo = caller.revealDirect(implementation); // may throw SecurityException
142 } catch (IllegalArgumentException e) {
143 throw new LambdaConversionException(implementation + " is not direct or cannot be cracked");
144 }
145 switch (implInfo.getReferenceKind()) {
146 case REF_invokeVirtual:
147 case REF_invokeInterface:
148 this.implClass = implMethodType.parameterType(0);
149 // reference kind reported by implInfo may not match implMethodType's first param
150 // Example: implMethodType is (Cloneable)String, implInfo is for Object.toString
151 this.implKind = implClass.isInterface() ? REF_invokeInterface : REF_invokeVirtual;
152 this.implIsInstanceMethod = true;
153 break;
154 case REF_invokeSpecial:
155 // JDK-8172817: should use referenced class here, but we don't know what it was
156 this.implClass = implInfo.getDeclaringClass();
157 this.implIsInstanceMethod = true;
158
159 // Classes compiled prior to dynamic nestmate support invoke a private instance
160 // method with REF_invokeSpecial. Newer classes use REF_invokeVirtual or
161 // REF_invokeInterface, and we can use that instruction in the lambda class.
162 if (targetClass == implClass && Modifier.isPrivate(implInfo.getModifiers())) {
163 this.implKind = implClass.isInterface() ? REF_invokeInterface : REF_invokeVirtual;
164 } else {
165 this.implKind = REF_invokeSpecial;
166 }
167 break;
168 case REF_invokeStatic:
169 case REF_newInvokeSpecial:
170 // JDK-8172817: should use referenced class here for invokestatic, but we don't know what it was
171 this.implClass = implInfo.getDeclaringClass();
172 this.implKind = implInfo.getReferenceKind();
173 this.implIsInstanceMethod = false;
174 break;
175 default:
176 throw new LambdaConversionException(String.format("Unsupported MethodHandle kind: %s", implInfo));
177 }
178
179 this.dynamicMethodType = dynamicMethodType;
180 this.isSerializable = isSerializable;
181 this.altInterfaces = altInterfaces;
182 this.altMethods = altMethods;
183
184 if (interfaceMethodName.isEmpty() ||
185 interfaceMethodName.indexOf('.') >= 0 ||
186 interfaceMethodName.indexOf(';') >= 0 ||
187 interfaceMethodName.indexOf('[') >= 0 ||
188 interfaceMethodName.indexOf('/') >= 0 ||
189 interfaceMethodName.indexOf('<') >= 0 ||
190 interfaceMethodName.indexOf('>') >= 0) {
191 throw new LambdaConversionException(String.format(
192 "Method name '%s' is not legal",
193 interfaceMethodName));
194 }
195
196 if (!interfaceClass.isInterface()) {
197 throw new LambdaConversionException(String.format(
198 "%s is not an interface",
199 interfaceClass.getName()));
200 }
201
202 for (Class<?> c : altInterfaces) {
203 if (!c.isInterface()) {
204 throw new LambdaConversionException(String.format(
205 "%s is not an interface",
206 c.getName()));
207 }
208 }
209 }
210
211 /**
212 * Build the CallSite.
213 *
214 * @return a CallSite, which, when invoked, will return an instance of the
215 * functional interface
216 * @throws LambdaConversionException
217 */
218 abstract CallSite buildCallSite()
219 throws LambdaConversionException;
220
221 /**
222 * Check the meta-factory arguments for errors
223 * @throws LambdaConversionException if there are improper conversions
224 */
225 void validateMetafactoryArgs() throws LambdaConversionException {
226 // Check arity: captured + SAM == impl
227 final int implArity = implMethodType.parameterCount();
228 final int capturedArity = factoryType.parameterCount();
229 final int samArity = interfaceMethodType.parameterCount();
230 final int dynamicArity = dynamicMethodType.parameterCount();
231 if (implArity != capturedArity + samArity) {
232 throw new LambdaConversionException(
233 String.format("Incorrect number of parameters for %s method %s; %d captured parameters, %d functional interface method parameters, %d implementation parameters",
234 implIsInstanceMethod ? "instance" : "static", implInfo,
235 capturedArity, samArity, implArity));
236 }
237 if (dynamicArity != samArity) {
238 throw new LambdaConversionException(
239 String.format("Incorrect number of parameters for %s method %s; %d dynamic parameters, %d functional interface method parameters",
240 implIsInstanceMethod ? "instance" : "static", implInfo,
241 dynamicArity, samArity));
242 }
243 for (MethodType bridgeMT : altMethods) {
244 if (bridgeMT.parameterCount() != samArity) {
245 throw new LambdaConversionException(
246 String.format("Incorrect number of parameters for bridge signature %s; incompatible with %s",
247 bridgeMT, interfaceMethodType));
248 }
249 }
250
251 // If instance: first captured arg (receiver) must be subtype of class where impl method is defined
252 final int capturedStart; // index of first non-receiver capture parameter in implMethodType
253 final int samStart; // index of first non-receiver sam parameter in implMethodType
254 if (implIsInstanceMethod) {
255 final Class<?> receiverClass;
256
257 // implementation is an instance method, adjust for receiver in captured variables / SAM arguments
258 if (capturedArity == 0) {
259 // receiver is function parameter
260 capturedStart = 0;
261 samStart = 1;
262 receiverClass = dynamicMethodType.parameterType(0);
263 } else {
264 // receiver is a captured variable
265 capturedStart = 1;
266 samStart = capturedArity;
267 receiverClass = factoryType.parameterType(0);
268 }
269
270 // check receiver type
271 if (!implClass.isAssignableFrom(receiverClass)) {
272 throw new LambdaConversionException(
273 String.format("Invalid receiver type %s; not a subtype of implementation type %s",
274 receiverClass, implClass));
275 }
276 } else {
277 // no receiver
278 capturedStart = 0;
279 samStart = capturedArity;
280 }
281
282 // Check for exact match on non-receiver captured arguments
283 for (int i=capturedStart; i<capturedArity; i++) {
284 Class<?> implParamType = implMethodType.parameterType(i);
285 Class<?> capturedParamType = factoryType.parameterType(i);
286 if (!capturedParamType.equals(implParamType)) {
287 throw new LambdaConversionException(
288 String.format("Type mismatch in captured lambda parameter %d: expecting %s, found %s",
289 i, capturedParamType, implParamType));
290 }
291 }
292 // Check for adaptation match on non-receiver SAM arguments
293 for (int i=samStart; i<implArity; i++) {
294 Class<?> implParamType = implMethodType.parameterType(i);
295 Class<?> dynamicParamType = dynamicMethodType.parameterType(i - capturedArity);
296 if (!isAdaptableTo(dynamicParamType, implParamType, true)) {
297 throw new LambdaConversionException(
298 String.format("Type mismatch for lambda argument %d: %s is not convertible to %s",
299 i, dynamicParamType, implParamType));
300 }
301 }
302
303 // Adaptation match: return type
304 Class<?> expectedType = dynamicMethodType.returnType();
305 Class<?> actualReturnType = implMethodType.returnType();
306 if (!isAdaptableToAsReturn(actualReturnType, expectedType)) {
307 throw new LambdaConversionException(
308 String.format("Type mismatch for lambda return: %s is not convertible to %s",
309 actualReturnType, expectedType));
310 }
311
312 // Check descriptors of generated methods
313 checkDescriptor(interfaceMethodType);
314 for (MethodType bridgeMT : altMethods) {
315 checkDescriptor(bridgeMT);
316 }
317 }
318
319 /** Validate that the given descriptor's types are compatible with {@code dynamicMethodType} **/
320 private void checkDescriptor(MethodType descriptor) throws LambdaConversionException {
321 for (int i = 0; i < dynamicMethodType.parameterCount(); i++) {
322 Class<?> dynamicParamType = dynamicMethodType.parameterType(i);
323 Class<?> descriptorParamType = descriptor.parameterType(i);
324 if (!descriptorParamType.isAssignableFrom(dynamicParamType)) {
325 String msg = String.format("Type mismatch for dynamic parameter %d: %s is not a subtype of %s",
326 i, dynamicParamType, descriptorParamType);
327 throw new LambdaConversionException(msg);
328 }
329 }
330
331 Class<?> dynamicReturnType = dynamicMethodType.returnType();
332 Class<?> descriptorReturnType = descriptor.returnType();
333 if (!isAdaptableToAsReturnStrict(dynamicReturnType, descriptorReturnType)) {
334 String msg = String.format("Type mismatch for lambda expected return: %s is not convertible to %s",
335 dynamicReturnType, descriptorReturnType);
336 throw new LambdaConversionException(msg);
337 }
338 }
339
340 /**
341 * Check type adaptability for parameter types.
342 * @param fromType Type to convert from
343 * @param toType Type to convert to
344 * @param strict If true, do strict checks, else allow that fromType may be parameterized
345 * @return True if 'fromType' can be passed to an argument of 'toType'
346 */
347 private boolean isAdaptableTo(Class<?> fromType, Class<?> toType, boolean strict) {
348 if (fromType.equals(toType)) {
349 return true;
350 }
351 if (fromType.isPrimitive()) {
352 Wrapper wfrom = forPrimitiveType(fromType);
353 if (toType.isPrimitive()) {
354 // both are primitive: widening
355 Wrapper wto = forPrimitiveType(toType);
356 return wto.isConvertibleFrom(wfrom);
357 } else {
358 // from primitive to reference: boxing
359 return toType.isAssignableFrom(wfrom.wrapperType());
360 }
361 } else {
362 if (toType.isPrimitive()) {
363 // from reference to primitive: unboxing
364 Wrapper wfrom;
365 if (isWrapperType(fromType) && (wfrom = forWrapperType(fromType)).primitiveType().isPrimitive()) {
366 // fromType is a primitive wrapper; unbox+widen
367 Wrapper wto = forPrimitiveType(toType);
368 return wto.isConvertibleFrom(wfrom);
369 } else {
370 // must be convertible to primitive
371 return !strict;
372 }
373 } else {
374 // both are reference types: fromType should be a superclass of toType.
375 return !strict || toType.isAssignableFrom(fromType);
376 }
377 }
378 }
379
380 /**
381 * Check type adaptability for return types --
382 * special handling of void type) and parameterized fromType
383 * @return True if 'fromType' can be converted to 'toType'
384 */
385 private boolean isAdaptableToAsReturn(Class<?> fromType, Class<?> toType) {
386 return toType.equals(void.class)
387 || !fromType.equals(void.class) && isAdaptableTo(fromType, toType, false);
388 }
389 private boolean isAdaptableToAsReturnStrict(Class<?> fromType, Class<?> toType) {
390 if (fromType.equals(void.class) || toType.equals(void.class)) return fromType.equals(toType);
391 else return isAdaptableTo(fromType, toType, true);
392 }
393
394
395 /*********** Logging support -- for debugging only, uncomment as needed
396 static final Executor logPool = Executors.newSingleThreadExecutor();
397 protected static void log(final String s) {
398 MethodHandleProxyLambdaMetafactory.logPool.execute(new Runnable() {
399 @Override
400 public void run() {
401 System.out.println(s);
402 }
403 });
404 }
405
406 protected static void log(final String s, final Throwable e) {
407 MethodHandleProxyLambdaMetafactory.logPool.execute(new Runnable() {
408 @Override
409 public void run() {
410 System.out.println(s);
411 e.printStackTrace(System.out);
412 }
413 });
414 }
415 ***********************/
416
417 }