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