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