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