1 /*
   2  * Copyright (c) 2010, 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 
  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.ConstantCallSite;
  33 import java.lang.invoke.MethodHandle;
  34 import java.lang.invoke.MethodHandles;
  35 import java.lang.invoke.MethodHandles.Lookup;
  36 import java.lang.invoke.MethodType;
  37 import jdk.dynalink.CallSiteDescriptor;
  38 import jdk.dynalink.DynamicLinker;
  39 import jdk.dynalink.DynamicLinkerFactory;
  40 import jdk.dynalink.beans.BeansLinker;
  41 import jdk.dynalink.beans.StaticClass;
  42 import jdk.dynalink.linker.GuardedInvocation;
  43 import jdk.dynalink.linker.GuardedInvocationTransformer;
  44 import jdk.dynalink.linker.LinkRequest;
  45 import jdk.dynalink.linker.LinkerServices;
  46 import jdk.dynalink.linker.MethodTypeConversionStrategy;
  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     // do not create me!!
  71     private Bootstrap() {
  72     }
  73 
  74     /**
  75      * Creates a Nashorn dynamic linker with the given app class loader.
  76      * @param appLoader the app class loader. It will be used to discover
  77      * additional language runtime linkers (if any).
  78      * @param unstableRelinkThreshold the unstable relink threshold
  79      * @return a newly created dynamic linker.
  80      */
  81     public static DynamicLinker createDynamicLinker(final ClassLoader appLoader,
  82             final int unstableRelinkThreshold) {
  83         final DynamicLinkerFactory factory = new DynamicLinkerFactory();
  84         final NashornBeansLinker nashornBeansLinker = new NashornBeansLinker();
  85         factory.setPrioritizedLinkers(
  86             new NashornLinker(),
  87             new NashornPrimitiveLinker(),
  88             new NashornStaticClassLinker(),
  89             new BoundCallableLinker(),
  90             new JavaSuperAdapterLinker(),
  91             new JSObjectLinker(nashornBeansLinker),
  92             new BrowserJSObjectLinker(nashornBeansLinker),
  93             new ReflectionCheckLinker());
  94         factory.setFallbackLinkers(nashornBeansLinker, new NashornBottomLinker());
  95         factory.setSyncOnRelink(true);
  96         factory.setPrelinkTransformer(new GuardedInvocationTransformer() {
  97             @Override
  98             public GuardedInvocation filter(final GuardedInvocation inv, final LinkRequest request, final LinkerServices linkerServices) {
  99                 final CallSiteDescriptor desc = request.getCallSiteDescriptor();
 100                 return OptimisticReturnFilters.filterOptimisticReturnValue(inv, desc).asType(linkerServices, desc.getMethodType());
 101             }
 102         });
 103         factory.setAutoConversionStrategy(new MethodTypeConversionStrategy() {
 104             @Override
 105             public MethodHandle asType(final MethodHandle target, final MethodType newType) {
 106                 return unboxReturnType(target, newType);
 107             }
 108         });
 109         factory.setInternalObjectsFilter(NashornBeansLinker.createHiddenObjectFilter());
 110         factory.setUnstableRelinkThreshold(unstableRelinkThreshold);
 111 
 112         // Linkers for any additional language runtimes deployed alongside Nashorn will be picked up by the factory.
 113         factory.setClassLoader(appLoader);
 114         return factory.createLinker();
 115     }
 116 
 117     /**
 118      * Returns if the given object is a "callable"
 119      * @param obj object to be checked for callability
 120      * @return true if the obj is callable
 121      */
 122     public static boolean isCallable(final Object obj) {
 123         if (obj == ScriptRuntime.UNDEFINED || obj == null) {
 124             return false;
 125         }
 126 
 127         return obj instanceof ScriptFunction ||
 128             isJSObjectFunction(obj) ||
 129             BeansLinker.isDynamicMethod(obj) ||
 130             obj instanceof BoundCallable ||
 131             isFunctionalInterfaceObject(obj) ||
 132             obj instanceof StaticClass;
 133     }
 134 
 135     /**
 136      * Returns true if the given object is a strict callable
 137      * @param callable the callable object to be checked for strictness
 138      * @return true if the obj is a strict callable, false if it is a non-strict callable.
 139      * @throws ECMAException with {@code TypeError} if the object is not a callable.
 140      */
 141     public static boolean isStrictCallable(final Object callable) {
 142         if (callable instanceof ScriptFunction) {
 143             return ((ScriptFunction)callable).isStrict();
 144         } else if (isJSObjectFunction(callable)) {
 145             return ((JSObject)callable).isStrictFunction();
 146         } else if (callable instanceof BoundCallable) {
 147             return isStrictCallable(((BoundCallable)callable).getCallable());
 148         } else if (BeansLinker.isDynamicMethod(callable) || callable instanceof StaticClass) {
 149             return false;
 150         }
 151         throw notFunction(callable);
 152     }
 153 
 154     private static ECMAException notFunction(final Object obj) {
 155         return typeError("not.a.function", ScriptRuntime.safeToString(obj));
 156     }
 157 
 158     private static boolean isJSObjectFunction(final Object obj) {
 159         return obj instanceof JSObject && ((JSObject)obj).isFunction();
 160     }
 161 
 162     /**
 163      * Returns if the given object is a dynalink Dynamic method
 164      * @param obj object to be checked
 165      * @return true if the obj is a dynamic method
 166      */
 167     public static boolean isDynamicMethod(final Object obj) {
 168         return BeansLinker.isDynamicMethod(obj instanceof BoundCallable ? ((BoundCallable)obj).getCallable() : obj);
 169     }
 170 
 171     /**
 172      * Returns if the given object is an instance of an interface annotated with
 173      * java.lang.FunctionalInterface
 174      * @param obj object to be checked
 175      * @return true if the obj is an instance of @FunctionalInterface interface
 176      */
 177     public static boolean isFunctionalInterfaceObject(final Object obj) {
 178         return !JSType.isPrimitive(obj) && (NashornBeansLinker.getFunctionalInterfaceMethodName(obj.getClass()) != null);
 179     }
 180 
 181     /**
 182      * Create a call site and link it for Nashorn. This version of the method conforms to the invokedynamic bootstrap
 183      * method expected signature and is referenced from Nashorn generated bytecode as the bootstrap method for all
 184      * invokedynamic instructions.
 185      * @param lookup MethodHandle lookup. Ignored as Nashorn only uses public lookup.
 186      * @param opDesc Dynalink dynamic operation descriptor.
 187      * @param type   Method type.
 188      * @param flags  flags for call type, trace/profile etc.
 189      * @return CallSite with MethodHandle to appropriate method or null if not found.
 190      */
 191     public static CallSite bootstrap(final Lookup lookup, final String opDesc, final MethodType type, final int flags) {
 192         return Context.getDynamicLinker(lookup.lookupClass()).link(LinkerCallSite.newLinkerCallSite(lookup, opDesc, type, flags));
 193     }
 194 
 195     /**
 196      * Boostrapper for math calls that may overflow
 197      * @param lookup         lookup
 198      * @param name           name of operation
 199      * @param type           method type
 200      * @param programPoint   program point to bind to callsite
 201      *
 202      * @return callsite for a math intrinsic node
 203      */
 204     public static CallSite mathBootstrap(final Lookup lookup, final String name, final MethodType type, final int programPoint) {
 205         final MethodHandle mh;
 206         switch (name) {
 207         case "iadd":
 208             mh = JSType.ADD_EXACT.methodHandle();
 209             break;
 210         case "isub":
 211             mh = JSType.SUB_EXACT.methodHandle();
 212             break;
 213         case "imul":
 214             mh = JSType.MUL_EXACT.methodHandle();
 215             break;
 216         case "idiv":
 217             mh = JSType.DIV_EXACT.methodHandle();
 218             break;
 219         case "irem":
 220             mh = JSType.REM_EXACT.methodHandle();
 221             break;
 222         case "ineg":
 223             mh = JSType.NEGATE_EXACT.methodHandle();


















 224             break;
 225         default:
 226             throw new AssertionError("unsupported math intrinsic");
 227         }
 228         return new ConstantCallSite(MH.insertArguments(mh, mh.type().parameterCount() - 1, programPoint));
 229     }
 230 
 231     /**
 232      * Returns a dynamic invoker for a specified dynamic operation using the
 233      * public lookup. You can use this method to create a method handle that
 234      * when invoked acts completely as if it were a Nashorn-linked call site.
 235      * Note that the available operations are encoded in the flags, see
 236      * {@link NashornCallSiteDescriptor} operation constants. If the operation
 237      * takes a name, it should be set otherwise empty name (not null) should be
 238      * used. All names (including the empty one) should be encoded using
 239      * {@link NameCodec#encode(String)}. Few examples:
 240      * <ul>
 241      *   <li>Get a named property with fixed name:
 242      *     <pre>
 243      * MethodHandle getColor = Boostrap.createDynamicInvoker(
 244      *     "color",
 245      *     NashornCallSiteDescriptor.GET_PROPERTY,
 246      *     Object.class, Object.class);
 247      * Object obj = ...; // somehow obtain the object
 248      * Object color = getColor.invokeExact(obj);
 249      *     </pre>
 250      *   </li>
 251      *   <li>Get a named property with variable name:
 252      *     <pre>
 253      * MethodHandle getProperty = Boostrap.createDynamicInvoker(
 254      *     NameCodec.encode(""),
 255      *     NashornCallSiteDescriptor.GET_PROPERTY,
 256      *     Object.class, Object.class, String.class);
 257      * Object obj = ...; // somehow obtain the object
 258      * Object color = getProperty.invokeExact(obj, "color");
 259      * Object shape = getProperty.invokeExact(obj, "shape");
 260      *
 261      * MethodHandle getNumProperty = Boostrap.createDynamicInvoker(
 262      *     NameCodec.encode(""),
 263      *     NashornCallSiteDescriptor.GET_ELEMENT,
 264      *     Object.class, Object.class, int.class);
 265      * Object elem42 = getNumProperty.invokeExact(obj, 42);
 266      *     </pre>
 267      *   </li>
 268      *   <li>Set a named property with fixed name:
 269      *     <pre>
 270      * MethodHandle setColor = Boostrap.createDynamicInvoker(
 271      *     "color",
 272      *     NashornCallSiteDescriptor.SET_PROPERTY,
 273      *     void.class, Object.class, Object.class);
 274      * Object obj = ...; // somehow obtain the object
 275      * setColor.invokeExact(obj, Color.BLUE);
 276      *     </pre>
 277      *   </li>
 278      *   <li>Set a property with variable name:
 279      *     <pre>
 280      * MethodHandle setProperty = Boostrap.createDynamicInvoker(
 281      *     NameCodec.encode(""),
 282      *     NashornCallSiteDescriptor.SET_PROPERTY,
 283      *     void.class, Object.class, String.class, Object.class);
 284      * Object obj = ...; // somehow obtain the object
 285      * setProperty.invokeExact(obj, "color", Color.BLUE);
 286      * setProperty.invokeExact(obj, "shape", Shape.CIRCLE);
 287      *     </pre>
 288      *   </li>
 289      *   <li>Call a function on an object; note it's a two-step process: get the
 290      *   method, then invoke the method. This is the actual:
 291      *     <pre>
 292      * MethodHandle findFooFunction = Boostrap.createDynamicInvoker(
 293      *     "foo",
 294      *     NashornCallSiteDescriptor.GET_METHOD,
 295      *     Object.class, Object.class);
 296      * Object obj = ...; // somehow obtain the object
 297      * Object foo_fn = findFooFunction.invokeExact(obj);
 298      * MethodHandle callFunctionWithTwoArgs = Boostrap.createDynamicCallInvoker(
 299      *     Object.class, Object.class, Object.class, Object.class, Object.class);
 300      * // Note: "call" operation takes a function, then a "this" value, then the arguments:
 301      * Object foo_retval = callFunctionWithTwoArgs.invokeExact(foo_fn, obj, arg1, arg2);
 302      *     </pre>
 303      *   </li>
 304      * </ul>
 305      * Few additional remarks:
 306      * <ul>
 307      * <li>Just as Nashorn works with any Java object, the invokers returned
 308      * from this method can also be applied to arbitrary Java objects in
 309      * addition to Nashorn JavaScript objects.</li>
 310      * <li>For invoking a named function on an object, you can also use the
 311      * {@link InvokeByName} convenience class.</li>
 312      * <li>There's no rule that the variable property identifier has to be a
 313      * {@code String} for {@code GET_PROPERTY/SET_PROPERTY} and {@code int} for
 314      * {@code GET_ELEMENT/SET_ELEMENT}. You can declare their type to be
 315      * {@code int}, {@code double}, {@code Object}, and so on regardless of the
 316      * kind of the operation.</li>
 317      * <li>You can be as specific in parameter types as you want. E.g. if you
 318      * know that the receiver of the operation will always be
 319      * {@code ScriptObject}, you can pass {@code ScriptObject.class} as its
 320      * parameter type. If you happen to link to a method that expects different
 321      * types, (you can use these invokers on POJOs too, after all, and end up
 322      * linking with their methods that have strongly-typed signatures), all
 323      * necessary conversions allowed by either Java or JavaScript will be
 324      * applied: if invoked methods specify either primitive or wrapped Java
 325      * numeric types, or {@code String} or {@code boolean/Boolean}, then the
 326      * parameters might be subjected to standard ECMAScript {@code ToNumber},
 327      * {@code ToString}, and {@code ToBoolean} conversion, respectively. Less
 328      * obviously, if the expected parameter type is a SAM type, and you pass a
 329      * JavaScript function, a proxy object implementing the SAM type and
 330      * delegating to the function will be passed. Linkage can often be optimized
 331      * when linkers have more specific type information than "everything can be
 332      * an object".</li>
 333      * <li>You can also be as specific in return types as you want. For return
 334      * types any necessary type conversion available in either Java or
 335      * JavaScript will be automatically applied, similar to the process
 336      * described for parameters, only in reverse direction: if you specify any
 337      * either primitive or wrapped Java numeric type, or {@code String} or
 338      * {@code boolean/Boolean}, then the return values will be subjected to
 339      * standard ECMAScript {@code ToNumber}, {@code ToString}, and
 340      * {@code ToBoolean} conversion, respectively. Less obviously, if the return
 341      * type is a SAM type, and the return value is a JavaScript function, a
 342      * proxy object implementing the SAM type and delegating to the function
 343      * will be returned.</li>
 344      * </ul>
 345      * @param name name at the call site. Must not be null. Must be encoded
 346      * using {@link NameCodec#encode(String)}. If the operation does not take a
 347      * name, use empty string (also has to be encoded).
 348      * @param flags the call site flags for the operation; see
 349      * {@link NashornCallSiteDescriptor} for available flags. The most important
 350      * part of the flags are the ones encoding the actual operation.
 351      * @param rtype the return type for the operation
 352      * @param ptypes the parameter types for the operation
 353      * @return MethodHandle for invoking the operation.
 354      */
 355     public static MethodHandle createDynamicInvoker(final String name, final int flags, final Class<?> rtype, final Class<?>... ptypes) {
 356         return bootstrap(MethodHandles.publicLookup(), name, MethodType.methodType(rtype, ptypes), flags).dynamicInvoker();
 357     }
 358 
 359     /**
 360      * Returns a dynamic invoker for the {@link NashornCallSiteDescriptor#CALL}
 361      * operation using the public lookup.
 362      * @param rtype the return type for the operation
 363      * @param ptypes the parameter types for the operation
 364      * @return a dynamic invoker for the {@code CALL} operation.
 365      */
 366     public static MethodHandle createDynamicCallInvoker(final Class<?> rtype, final Class<?>... ptypes) {
 367         return createDynamicInvoker("", NashornCallSiteDescriptor.CALL, rtype, ptypes);
 368     }
 369 
 370     /**
 371      * Returns a dynamic invoker for a specified dynamic operation using the
 372      * public lookup. Similar to
 373      * {@link #createDynamicInvoker(String, int, Class, Class...)} but with
 374      * already precomposed method type.
 375      * @param name name at the call site.
 376      * @param flags flags at the call site
 377      * @param type the method type for the operation
 378      * @return MethodHandle for invoking the operation.
 379      */
 380     public static MethodHandle createDynamicInvoker(final String name, final int flags, final MethodType type) {
 381         return bootstrap(MethodHandles.publicLookup(), name, type, flags).dynamicInvoker();
 382     }
 383 
 384     /**
 385      * Binds any object Nashorn can use as a [[Callable]] to a receiver and optionally arguments.
 386      * @param callable the callable to bind
 387      * @param boundThis the bound "this" value.
 388      * @param boundArgs the bound arguments. Can be either null or empty array to signify no arguments are bound.
 389      * @return a bound callable.
 390      * @throws ECMAException with {@code TypeError} if the object is not a callable.
 391      */
 392     public static Object bindCallable(final Object callable, final Object boundThis, final Object[] boundArgs) {
 393         if (callable instanceof ScriptFunction) {
 394             return ((ScriptFunction)callable).createBound(boundThis, boundArgs);
 395         } else if (callable instanceof BoundCallable) {
 396             return ((BoundCallable)callable).bind(boundArgs);
 397         } else if (isCallable(callable)) {
 398             return new BoundCallable(callable, boundThis, boundArgs);
 399         }
 400         throw notFunction(callable);
 401     }
 402 
 403     /**
 404      * Creates a super-adapter for an adapter, that is, an adapter to the adapter that allows invocation of superclass
 405      * methods on it.
 406      * @param adapter the original adapter
 407      * @return a new adapter that can be used to invoke super methods on the original adapter.
 408      */
 409     public static Object createSuperAdapter(final Object adapter) {
 410         return new JavaSuperAdapter(adapter);
 411     }
 412 
 413     /**
 414      * If the given class is a reflection-specific class (anything in {@code java.lang.reflect} and
 415      * {@code java.lang.invoke} package, as well a {@link Class} and any subclass of {@link ClassLoader}) and there is
 416      * a security manager in the system, then it checks the {@code nashorn.JavaReflection} {@code RuntimePermission}.
 417      * @param clazz the class being tested
 418      * @param isStatic is access checked for static members (or instance members)
 419      */
 420     public static void checkReflectionAccess(final Class<?> clazz, final boolean isStatic) {
 421         ReflectionCheckLinker.checkReflectionAccess(clazz, isStatic);
 422     }
 423 
 424     /**
 425      * Returns the Nashorn's internally used dynamic linker's services object. Note that in code that is processing a
 426      * linking request, you will normally use the {@code LinkerServices} object passed by whatever top-level linker
 427      * invoked the linking (if the call site is in Nashorn-generated code, you'll get this object anyway). You should
 428      * only resort to retrieving a linker services object using this method when you need some linker services (e.g.
 429      * type converter method handles) outside of a code path that is linking a call site.
 430      * @return Nashorn's internal dynamic linker's services object.
 431      */
 432     public static LinkerServices getLinkerServices() {
 433         return Context.getDynamicLinker().getLinkerServices();
 434     }
 435 
 436     /**
 437      * Takes a guarded invocation, and ensures its method and guard conform to the type of the call descriptor, using
 438      * all type conversions allowed by the linker's services. This method is used by Nashorn's linkers as a last step
 439      * before returning guarded invocations. Most of the code used to produce the guarded invocations does not make an
 440      * effort to coordinate types of the methods, and so a final type adjustment before a guarded invocation is returned
 441      * to the aggregating linker is the responsibility of the linkers themselves.
 442      * @param inv the guarded invocation that needs to be type-converted. Can be null.
 443      * @param linkerServices the linker services object providing the type conversions.
 444      * @param desc the call site descriptor to whose method type the invocation needs to conform.
 445      * @return the type-converted guarded invocation. If input is null, null is returned. If the input invocation
 446      * already conforms to the requested type, it is returned unchanged.
 447      */
 448     static GuardedInvocation asTypeSafeReturn(final GuardedInvocation inv, final LinkerServices linkerServices, final CallSiteDescriptor desc) {
 449         return inv == null ? null : inv.asTypeSafeReturn(linkerServices, desc.getMethodType());
 450     }
 451 
 452     /**
 453      * Adapts the return type of the method handle with {@code explicitCastArguments} when it is an unboxing
 454      * conversion. This will ensure that nulls are unwrapped to false or 0.
 455      * @param target the target method handle
 456      * @param newType the desired new type. Note that this method does not adapt the method handle completely to the
 457      * new type, it only adapts the return type; this is allowed as per
 458      * {@link DynamicLinkerFactory#setAutoConversionStrategy(MethodTypeConversionStrategy)}, which is what this method
 459      * is used for.
 460      * @return the method handle with adapted return type, if it required an unboxing conversion.
 461      */
 462     private static MethodHandle unboxReturnType(final MethodHandle target, final MethodType newType) {
 463         final MethodType targetType = target.type();
 464         final Class<?> oldReturnType = targetType.returnType();
 465         final Class<?> newReturnType = newType.returnType();
 466         if (TypeUtilities.isWrapperType(oldReturnType)) {
 467             if (newReturnType.isPrimitive()) {
 468                 // The contract of setAutoConversionStrategy is such that the difference between newType and targetType
 469                 // can only be JLS method invocation conversions.
 470                 assert TypeUtilities.isMethodInvocationConvertible(oldReturnType, newReturnType);
 471                 return MethodHandles.explicitCastArguments(target, targetType.changeReturnType(newReturnType));
 472             }
 473         } else if (oldReturnType == void.class && newReturnType == Object.class) {
 474             return MethodHandles.filterReturnValue(target, VOID_TO_OBJECT);
 475         }
 476         return target;
 477     }
 478 }
--- EOF ---