1 /*
2 * Copyright (c) 2010, 2016, 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.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup;
29 import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
30
31 import java.lang.invoke.CallSite;
32 import java.lang.invoke.MethodHandle;
33 import java.lang.invoke.MethodHandles;
34 import java.lang.invoke.MethodHandles.Lookup;
35 import java.lang.invoke.MethodType;
36 import java.util.Collections;
37 import java.util.List;
38 import jdk.dynalink.CallSiteDescriptor;
39 import jdk.dynalink.DynamicLinker;
40 import jdk.dynalink.DynamicLinkerFactory;
41 import jdk.dynalink.beans.BeansLinker;
42 import jdk.dynalink.beans.StaticClass;
43 import jdk.dynalink.linker.GuardedInvocation;
44 import jdk.dynalink.linker.GuardingDynamicLinker;
45 import jdk.dynalink.linker.LinkRequest;
46 import jdk.dynalink.linker.LinkerServices;
47 import jdk.dynalink.linker.MethodTypeConversionStrategy;
48 import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker;
49 import jdk.dynalink.linker.support.TypeUtilities;
50 import jdk.nashorn.api.scripting.JSObject;
51 import jdk.nashorn.internal.codegen.CompilerConstants.Call;
52 import jdk.nashorn.internal.lookup.MethodHandleFactory;
53 import jdk.nashorn.internal.lookup.MethodHandleFunctionality;
54 import jdk.nashorn.internal.runtime.Context;
55 import jdk.nashorn.internal.runtime.ECMAException;
56 import jdk.nashorn.internal.runtime.JSType;
57 import jdk.nashorn.internal.runtime.OptimisticReturnFilters;
58 import jdk.nashorn.internal.runtime.ScriptFunction;
59 import jdk.nashorn.internal.runtime.ScriptRuntime;
60
61 /**
62 * This class houses bootstrap method for invokedynamic instructions generated by compiler.
63 */
64 public final class Bootstrap {
65 /** Reference to the seed boostrap function */
66 public static final Call BOOTSTRAP = staticCallNoLookup(Bootstrap.class, "bootstrap", CallSite.class, Lookup.class, String.class, MethodType.class, int.class);
67
68 private static final MethodHandleFunctionality MH = MethodHandleFactory.getFunctionality();
69
70 private static final MethodHandle VOID_TO_OBJECT = MH.constant(Object.class, ScriptRuntime.UNDEFINED);
71
72 private static final BeansLinker beansLinker = new BeansLinker(Bootstrap::createMissingMemberHandler);
73 private static final GuardingDynamicLinker[] prioritizedLinkers;
74 private static final GuardingDynamicLinker[] fallbackLinkers;
75
76 static {
77 final NashornBeansLinker nashornBeansLinker = new NashornBeansLinker(beansLinker);
78 prioritizedLinkers = new GuardingDynamicLinker[] {
79 new NashornLinker(),
80 new NashornPrimitiveLinker(),
81 new BoundCallableLinker(),
82 new JavaSuperAdapterLinker(beansLinker),
83 new JSObjectLinker(nashornBeansLinker),
84 new BrowserJSObjectLinker(nashornBeansLinker),
85 new ReflectionCheckLinker()
86 };
87 fallbackLinkers = new GuardingDynamicLinker[] {
88 new NashornStaticClassLinker(beansLinker),
89 nashornBeansLinker,
90 new NashornBottomLinker()
91 };
92 }
93
94 // do not create me!!
95 private Bootstrap() {
96 }
97
98 /**
99 * Returns a list of exposed nashorn dynalink linkers.
100 *
101 * @return a list of exposed nashorn dynalink linkers.
102 */
103 public static List<GuardingDynamicLinker> getExposedLinkers() {
104 // we have to create BeansLinker without nashorn specific missing member handler!
105 // Or else, we'd return values such as 'undefined' to the external world!
106 final NashornBeansLinker nbl = new NashornBeansLinker(new BeansLinker());
107 final JSObjectLinker linker = new JSObjectLinker(nbl);
108 return Collections.singletonList(linker);
109 }
110
111 /**
112 * Creates a Nashorn dynamic linker with the given app class loader.
113 * @param appLoader the app class loader. It will be used to discover
114 * additional language runtime linkers (if any).
115 * @param unstableRelinkThreshold the unstable relink threshold
116 * @return a newly created dynamic linker.
117 */
118 public static DynamicLinker createDynamicLinker(final ClassLoader appLoader,
119 final int unstableRelinkThreshold) {
120 final DynamicLinkerFactory factory = new DynamicLinkerFactory();
121 factory.setPrioritizedLinkers(prioritizedLinkers);
122 factory.setFallbackLinkers(fallbackLinkers);
123 factory.setSyncOnRelink(true);
124 factory.setPrelinkTransformer((inv, request, linkerServices) -> {
125 final CallSiteDescriptor desc = request.getCallSiteDescriptor();
126 return OptimisticReturnFilters.filterOptimisticReturnValue(inv, desc).asType(linkerServices, desc.getMethodType());
127 });
128 factory.setAutoConversionStrategy(Bootstrap::unboxReturnType);
129 factory.setInternalObjectsFilter(NashornBeansLinker.createHiddenObjectFilter());
130 factory.setUnstableRelinkThreshold(unstableRelinkThreshold);
131
132 // Linkers for any additional language runtimes deployed alongside Nashorn will be picked up by the factory.
133 factory.setClassLoader(appLoader);
134 return factory.createLinker();
135 }
136
137 /**
138 * Returns a dynamic linker for the specific Java class using beans semantics.
139 * @param clazz the Java class
140 * @return a dynamic linker for the specific Java class using beans semantics.
141 */
142 public static TypeBasedGuardingDynamicLinker getBeanLinkerForClass(final Class<?> clazz) {
143 return beansLinker.getLinkerForClass(clazz);
144 }
145
146 /**
147 * Returns if the given object is a "callable"
148 * @param obj object to be checked for callability
149 * @return true if the obj is callable
150 */
151 public static boolean isCallable(final Object obj) {
152 if (obj == ScriptRuntime.UNDEFINED || obj == null) {
153 return false;
154 }
155
156 return obj instanceof ScriptFunction ||
157 isJSObjectFunction(obj) ||
158 BeansLinker.isDynamicMethod(obj) ||
159 obj instanceof BoundCallable ||
160 isFunctionalInterfaceObject(obj) ||
161 obj instanceof StaticClass;
162 }
163
164 /**
165 * Returns true if the given object is a strict callable
166 * @param callable the callable object to be checked for strictness
167 * @return true if the obj is a strict callable, false if it is a non-strict callable.
168 * @throws ECMAException with {@code TypeError} if the object is not a callable.
169 */
170 public static boolean isStrictCallable(final Object callable) {
171 if (callable instanceof ScriptFunction) {
172 return ((ScriptFunction)callable).isStrict();
173 } else if (isJSObjectFunction(callable)) {
174 return ((JSObject)callable).isStrictFunction();
175 } else if (callable instanceof BoundCallable) {
176 return isStrictCallable(((BoundCallable)callable).getCallable());
177 } else if (BeansLinker.isDynamicMethod(callable) ||
178 callable instanceof StaticClass ||
179 isFunctionalInterfaceObject(callable)) {
180 return false;
181 }
182 throw notFunction(callable);
183 }
184
185 private static ECMAException notFunction(final Object obj) {
186 return typeError("not.a.function", ScriptRuntime.safeToString(obj));
187 }
188
189 private static boolean isJSObjectFunction(final Object obj) {
190 return obj instanceof JSObject && ((JSObject)obj).isFunction();
191 }
192
193 /**
194 * Returns if the given object is a dynalink Dynamic method
195 * @param obj object to be checked
196 * @return true if the obj is a dynamic method
197 */
198 public static boolean isDynamicMethod(final Object obj) {
199 return BeansLinker.isDynamicMethod(obj instanceof BoundCallable ? ((BoundCallable)obj).getCallable() : obj);
200 }
201
202 /**
203 * Returns if the given object is an instance of an interface annotated with
204 * java.lang.FunctionalInterface
205 * @param obj object to be checked
206 * @return true if the obj is an instance of @FunctionalInterface interface
207 */
208 public static boolean isFunctionalInterfaceObject(final Object obj) {
209 return !JSType.isPrimitive(obj) && (NashornBeansLinker.getFunctionalInterfaceMethodName(obj.getClass()) != null);
210 }
211
212 /**
213 * Create a call site and link it for Nashorn. This version of the method conforms to the invokedynamic bootstrap
214 * method expected signature and is referenced from Nashorn generated bytecode as the bootstrap method for all
215 * invokedynamic instructions.
216 * @param lookup MethodHandle lookup.
217 * @param opDesc Dynalink dynamic operation descriptor.
218 * @param type Method type.
219 * @param flags flags for call type, trace/profile etc.
220 * @return CallSite with MethodHandle to appropriate method or null if not found.
221 */
222 public static CallSite bootstrap(final Lookup lookup, final String opDesc, final MethodType type, final int flags) {
223 return Context.getDynamicLinker(lookup.lookupClass()).link(LinkerCallSite.newLinkerCallSite(lookup, opDesc, type, flags));
224 }
225
226 /**
227 * Returns a dynamic invoker for a specified dynamic operation using the
228 * public lookup. You can use this method to create a method handle that
229 * when invoked acts completely as if it were a Nashorn-linked call site.
230 * Note that the available operations are encoded in the flags, see
231 * {@link NashornCallSiteDescriptor} operation constants. If the operation
232 * takes a name, it should be set otherwise empty name (not null) should be
233 * used. All names (including the empty one) should be encoded using
234 * {@link NameCodec#encode(String)}. Few examples:
235 * <ul>
236 * <li>Get a named property with fixed name:
237 * <pre>
238 * MethodHandle getColor = Boostrap.createDynamicInvoker(
239 * "color",
240 * NashornCallSiteDescriptor.GET_PROPERTY,
241 * Object.class, Object.class);
242 * Object obj = ...; // somehow obtain the object
243 * Object color = getColor.invokeExact(obj);
244 * </pre>
245 * </li>
246 * <li>Get a named property with variable name:
247 * <pre>
248 * MethodHandle getProperty = Boostrap.createDynamicInvoker(
249 * NameCodec.encode(""),
250 * NashornCallSiteDescriptor.GET_PROPERTY,
251 * Object.class, Object.class, String.class);
252 * Object obj = ...; // somehow obtain the object
253 * Object color = getProperty.invokeExact(obj, "color");
254 * Object shape = getProperty.invokeExact(obj, "shape");
255 *
256 * MethodHandle getNumProperty = Boostrap.createDynamicInvoker(
257 * NameCodec.encode(""),
258 * NashornCallSiteDescriptor.GET_ELEMENT,
259 * Object.class, Object.class, int.class);
260 * Object elem42 = getNumProperty.invokeExact(obj, 42);
261 * </pre>
262 * </li>
263 * <li>Set a named property with fixed name:
264 * <pre>
265 * MethodHandle setColor = Boostrap.createDynamicInvoker(
266 * "color",
267 * NashornCallSiteDescriptor.SET_PROPERTY,
268 * void.class, Object.class, Object.class);
269 * Object obj = ...; // somehow obtain the object
270 * setColor.invokeExact(obj, Color.BLUE);
271 * </pre>
272 * </li>
273 * <li>Set a property with variable name:
274 * <pre>
275 * MethodHandle setProperty = Boostrap.createDynamicInvoker(
276 * NameCodec.encode(""),
277 * NashornCallSiteDescriptor.SET_PROPERTY,
278 * void.class, Object.class, String.class, Object.class);
279 * Object obj = ...; // somehow obtain the object
280 * setProperty.invokeExact(obj, "color", Color.BLUE);
281 * setProperty.invokeExact(obj, "shape", Shape.CIRCLE);
282 * </pre>
283 * </li>
284 * <li>Call a function on an object; note it's a two-step process: get the
285 * method, then invoke the method. This is the actual:
286 * <pre>
287 * MethodHandle findFooFunction = Boostrap.createDynamicInvoker(
288 * "foo",
289 * NashornCallSiteDescriptor.GET_METHOD,
290 * Object.class, Object.class);
291 * Object obj = ...; // somehow obtain the object
292 * Object foo_fn = findFooFunction.invokeExact(obj);
293 * MethodHandle callFunctionWithTwoArgs = Boostrap.createDynamicCallInvoker(
294 * Object.class, Object.class, Object.class, Object.class, Object.class);
295 * // Note: "call" operation takes a function, then a "this" value, then the arguments:
296 * Object foo_retval = callFunctionWithTwoArgs.invokeExact(foo_fn, obj, arg1, arg2);
297 * </pre>
298 * </li>
299 * </ul>
300 * Few additional remarks:
301 * <ul>
302 * <li>Just as Nashorn works with any Java object, the invokers returned
303 * from this method can also be applied to arbitrary Java objects in
304 * addition to Nashorn JavaScript objects.</li>
305 * <li>For invoking a named function on an object, you can also use the
306 * {@link InvokeByName} convenience class.</li>
307 * <li>There's no rule that the variable property identifier has to be a
308 * {@code String} for {@code GET_PROPERTY/SET_PROPERTY} and {@code int} for
309 * {@code GET_ELEMENT/SET_ELEMENT}. You can declare their type to be
310 * {@code int}, {@code double}, {@code Object}, and so on regardless of the
311 * kind of the operation.</li>
312 * <li>You can be as specific in parameter types as you want. E.g. if you
313 * know that the receiver of the operation will always be
314 * {@code ScriptObject}, you can pass {@code ScriptObject.class} as its
315 * parameter type. If you happen to link to a method that expects different
316 * types, (you can use these invokers on POJOs too, after all, and end up
317 * linking with their methods that have strongly-typed signatures), all
318 * necessary conversions allowed by either Java or JavaScript will be
319 * applied: if invoked methods specify either primitive or wrapped Java
320 * numeric types, or {@code String} or {@code boolean/Boolean}, then the
321 * parameters might be subjected to standard ECMAScript {@code ToNumber},
322 * {@code ToString}, and {@code ToBoolean} conversion, respectively. Less
323 * obviously, if the expected parameter type is a SAM type, and you pass a
324 * JavaScript function, a proxy object implementing the SAM type and
325 * delegating to the function will be passed. Linkage can often be optimized
326 * when linkers have more specific type information than "everything can be
327 * an object".</li>
328 * <li>You can also be as specific in return types as you want. For return
329 * types any necessary type conversion available in either Java or
330 * JavaScript will be automatically applied, similar to the process
331 * described for parameters, only in reverse direction: if you specify any
332 * either primitive or wrapped Java numeric type, or {@code String} or
333 * {@code boolean/Boolean}, then the return values will be subjected to
334 * standard ECMAScript {@code ToNumber}, {@code ToString}, and
335 * {@code ToBoolean} conversion, respectively. Less obviously, if the return
336 * type is a SAM type, and the return value is a JavaScript function, a
337 * proxy object implementing the SAM type and delegating to the function
338 * will be returned.</li>
339 * </ul>
340 * @param name name at the call site. Must not be null. Must be encoded
341 * using {@link NameCodec#encode(String)}. If the operation does not take a
342 * name, use empty string (also has to be encoded).
343 * @param flags the call site flags for the operation; see
344 * {@link NashornCallSiteDescriptor} for available flags. The most important
345 * part of the flags are the ones encoding the actual operation.
346 * @param rtype the return type for the operation
347 * @param ptypes the parameter types for the operation
348 * @return MethodHandle for invoking the operation.
349 */
350 public static MethodHandle createDynamicInvoker(final String name, final int flags, final Class<?> rtype, final Class<?>... ptypes) {
351 return bootstrap(MethodHandles.publicLookup(), name, MethodType.methodType(rtype, ptypes), flags).dynamicInvoker();
352 }
353
354 /**
355 * Returns a dynamic invoker for the {@link NashornCallSiteDescriptor#CALL}
356 * operation using the public lookup.
357 * @param rtype the return type for the operation
358 * @param ptypes the parameter types for the operation
359 * @return a dynamic invoker for the {@code CALL} operation.
360 */
361 public static MethodHandle createDynamicCallInvoker(final Class<?> rtype, final Class<?>... ptypes) {
362 return createDynamicInvoker("", NashornCallSiteDescriptor.CALL, rtype, ptypes);
363 }
364
365 /**
366 * Returns a dynamic invoker for a specified dynamic operation using the
367 * public lookup. Similar to
368 * {@link #createDynamicInvoker(String, int, Class, Class...)} but with
369 * already precomposed method type.
370 * @param name name at the call site.
371 * @param flags flags at the call site
372 * @param type the method type for the operation
373 * @return MethodHandle for invoking the operation.
374 */
375 public static MethodHandle createDynamicInvoker(final String name, final int flags, final MethodType type) {
376 return bootstrap(MethodHandles.publicLookup(), name, type, flags).dynamicInvoker();
377 }
378
379 /**
380 * Binds any object Nashorn can use as a [[Callable]] to a receiver and optionally arguments.
381 * @param callable the callable to bind
382 * @param boundThis the bound "this" value.
383 * @param boundArgs the bound arguments. Can be either null or empty array to signify no arguments are bound.
384 * @return a bound callable.
385 * @throws ECMAException with {@code TypeError} if the object is not a callable.
386 */
387 public static Object bindCallable(final Object callable, final Object boundThis, final Object[] boundArgs) {
388 if (callable instanceof ScriptFunction) {
389 return ((ScriptFunction)callable).createBound(boundThis, boundArgs);
390 } else if (callable instanceof BoundCallable) {
391 return ((BoundCallable)callable).bind(boundArgs);
392 } else if (isCallable(callable)) {
393 return new BoundCallable(callable, boundThis, boundArgs);
394 }
395 throw notFunction(callable);
396 }
397
398 /**
399 * Creates a super-adapter for an adapter, that is, an adapter to the adapter that allows invocation of superclass
400 * methods on it.
401 * @param adapter the original adapter
402 * @return a new adapter that can be used to invoke super methods on the original adapter.
403 */
404 public static Object createSuperAdapter(final Object adapter) {
405 return new JavaSuperAdapter(adapter);
406 }
407
408 /**
409 * If the given class is a reflection-specific class (anything in {@code java.lang.reflect} and
410 * {@code java.lang.invoke} package, as well a {@link Class} and any subclass of {@link ClassLoader}) and there is
411 * a security manager in the system, then it checks the {@code nashorn.JavaReflection} {@code RuntimePermission}.
412 * @param clazz the class being tested
413 * @param isStatic is access checked for static members (or instance members)
414 */
415 public static void checkReflectionAccess(final Class<?> clazz, final boolean isStatic) {
416 ReflectionCheckLinker.checkReflectionAccess(clazz, isStatic);
417 }
418
419 /**
420 * Returns the Nashorn's internally used dynamic linker's services object. Note that in code that is processing a
421 * linking request, you will normally use the {@code LinkerServices} object passed by whatever top-level linker
422 * invoked the linking (if the call site is in Nashorn-generated code, you'll get this object anyway). You should
423 * only resort to retrieving a linker services object using this method when you need some linker services (e.g.
424 * type converter method handles) outside of a code path that is linking a call site.
425 * @return Nashorn's internal dynamic linker's services object.
426 */
427 public static LinkerServices getLinkerServices() {
428 return Context.getDynamicLinker().getLinkerServices();
429 }
430
431 /**
432 * Takes a guarded invocation, and ensures its method and guard conform to the type of the call descriptor, using
433 * all type conversions allowed by the linker's services. This method is used by Nashorn's linkers as a last step
434 * before returning guarded invocations. Most of the code used to produce the guarded invocations does not make an
435 * effort to coordinate types of the methods, and so a final type adjustment before a guarded invocation is returned
436 * to the aggregating linker is the responsibility of the linkers themselves.
437 * @param inv the guarded invocation that needs to be type-converted. Can be null.
438 * @param linkerServices the linker services object providing the type conversions.
439 * @param desc the call site descriptor to whose method type the invocation needs to conform.
440 * @return the type-converted guarded invocation. If input is null, null is returned. If the input invocation
441 * already conforms to the requested type, it is returned unchanged.
442 */
443 static GuardedInvocation asTypeSafeReturn(final GuardedInvocation inv, final LinkerServices linkerServices, final CallSiteDescriptor desc) {
444 return inv == null ? null : inv.asTypeSafeReturn(linkerServices, desc.getMethodType());
445 }
446
447 /**
448 * Adapts the return type of the method handle with {@code explicitCastArguments} when it is an unboxing
449 * conversion. This will ensure that nulls are unwrapped to false or 0.
450 * @param target the target method handle
451 * @param newType the desired new type. Note that this method does not adapt the method handle completely to the
452 * new type, it only adapts the return type; this is allowed as per
453 * {@link DynamicLinkerFactory#setAutoConversionStrategy(MethodTypeConversionStrategy)}, which is what this method
454 * is used for.
455 * @return the method handle with adapted return type, if it required an unboxing conversion.
456 */
457 private static MethodHandle unboxReturnType(final MethodHandle target, final MethodType newType) {
458 final MethodType targetType = target.type();
459 final Class<?> oldReturnType = targetType.returnType();
460 final Class<?> newReturnType = newType.returnType();
461 if (TypeUtilities.isWrapperType(oldReturnType)) {
462 if (newReturnType.isPrimitive()) {
463 // The contract of setAutoConversionStrategy is such that the difference between newType and targetType
464 // can only be JLS method invocation conversions.
465 assert TypeUtilities.isMethodInvocationConvertible(oldReturnType, newReturnType);
466 return MethodHandles.explicitCastArguments(target, targetType.changeReturnType(newReturnType));
467 }
468 } else if (oldReturnType == void.class && newReturnType == Object.class) {
469 return MethodHandles.filterReturnValue(target, VOID_TO_OBJECT);
470 }
471 return target;
472 }
473
474 private static MethodHandle createMissingMemberHandler(
475 final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
476 if (BrowserJSObjectLinker.canLinkTypeStatic(linkRequest.getReceiver().getClass())) {
477 // Don't create missing member handlers for the browser JS objects as they
478 // have their own logic.
479 return null;
480 }
481 return NashornBottomLinker.linkMissingBeanMember(linkRequest, linkerServices);
482 }
483 }