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 30 import java.lang.invoke.CallSite; 31 import java.lang.invoke.MethodHandle; 32 import java.lang.invoke.MethodHandles; 33 import java.lang.invoke.MethodHandles.Lookup; 34 import java.lang.invoke.MethodType; 35 import jdk.internal.dynalink.CallSiteDescriptor; 36 import jdk.internal.dynalink.DynamicLinker; 37 import jdk.internal.dynalink.DynamicLinkerFactory; 38 import jdk.internal.dynalink.beans.BeansLinker; 39 import jdk.internal.dynalink.beans.StaticClass; 40 import jdk.internal.dynalink.linker.GuardedInvocation; 41 import jdk.internal.dynalink.linker.LinkerServices; 42 import jdk.nashorn.api.scripting.JSObject; 43 import jdk.nashorn.internal.codegen.CompilerConstants.Call; 44 import jdk.nashorn.internal.codegen.RuntimeCallSite; 45 import jdk.nashorn.internal.runtime.JSType; 46 import jdk.nashorn.internal.runtime.ScriptFunction; 47 import jdk.nashorn.internal.runtime.ScriptRuntime; 48 import jdk.nashorn.internal.runtime.options.Options; 49 50 /** 51 * This class houses bootstrap method for invokedynamic instructions generated by compiler. 52 */ 53 public final class Bootstrap { 54 /** Reference to the seed boostrap function */ 55 public static final Call BOOTSTRAP = staticCallNoLookup(Bootstrap.class, "bootstrap", CallSite.class, Lookup.class, String.class, MethodType.class, int.class); 56 57 // do not create me!! 58 private Bootstrap() { 59 } 60 61 private static final DynamicLinker dynamicLinker; 62 static { 63 final DynamicLinkerFactory factory = new DynamicLinkerFactory(); 64 final NashornBeansLinker nashornBeansLinker = new NashornBeansLinker(); 65 final JSObjectLinker jsObjectLinker = new JSObjectLinker(nashornBeansLinker); 66 factory.setPrioritizedLinkers(new NashornLinker(), new NashornPrimitiveLinker(), new NashornStaticClassLinker(), 67 new BoundDynamicMethodLinker(), new JavaSuperAdapterLinker(), jsObjectLinker, new ReflectionCheckLinker()); 68 factory.setFallbackLinkers(nashornBeansLinker, new NashornBottomLinker()); 69 factory.setSyncOnRelink(true); 70 final int relinkThreshold = Options.getIntProperty("nashorn.unstable.relink.threshold", -1); 71 if (relinkThreshold > -1) { 72 factory.setUnstableRelinkThreshold(relinkThreshold); 73 } 74 75 // Linkers for any additional language runtimes deployed alongside Nashorn will be picked up by the factory. 76 factory.setClassLoader(Bootstrap.class.getClassLoader()); 77 78 dynamicLinker = factory.createLinker(); 79 } 80 81 /** 82 * Returns if the given object is a "callable" 83 * @param obj object to be checked for callability 84 * @return true if the obj is callable 85 */ 86 public static boolean isCallable(final Object obj) { 87 if (obj == ScriptRuntime.UNDEFINED || obj == null) { 88 return false; 89 } 90 91 return obj instanceof ScriptFunction || 92 ((obj instanceof JSObject) && ((JSObject)obj).isFunction()) || 93 isDynamicMethod(obj) || 94 isFunctionalInterfaceObject(obj) || 95 obj instanceof StaticClass; 96 } 97 98 /** 99 * Returns if the given object is a dynalink Dynamic method 100 * @param obj object to be checked 101 * @return true if the obj is a dynamic method 102 */ 103 public static boolean isDynamicMethod(final Object obj) { 104 return obj instanceof BoundDynamicMethod || BeansLinker.isDynamicMethod(obj); 105 } 106 107 /** 108 * Returns if the given object is an instance of an interface annotated with 109 * java.lang.FunctionalInterface 110 * @param obj object to be checked 111 * @return true if the obj is an instance of @FunctionalInterface interface 112 */ 113 public static boolean isFunctionalInterfaceObject(final Object obj) { 114 return !JSType.isPrimitive(obj) && (NashornBottomLinker.getFunctionalInterfaceMethod(obj.getClass()) != null); 115 } 116 117 /** 118 * Create a call site and link it for Nashorn. This version of the method conforms to the invokedynamic bootstrap 119 * method expected signature and is referenced from Nashorn generated bytecode as the bootstrap method for all 120 * invokedynamic instructions. 121 * @param lookup MethodHandle lookup. Ignored as Nashorn only uses public lookup. 122 * @param opDesc Dynalink dynamic operation descriptor. 123 * @param type Method type. 124 * @param flags flags for call type, trace/profile etc. 125 * @return CallSite with MethodHandle to appropriate method or null if not found. 126 */ 127 public static CallSite bootstrap(final Lookup lookup, final String opDesc, final MethodType type, final int flags) { 128 return dynamicLinker.link(LinkerCallSite.newLinkerCallSite(lookup, opDesc, type, flags)); 129 } 130 131 /** 132 * Bootstrapper for a specialized Runtime call 133 * 134 * @param lookup lookup 135 * @param initialName initial name for callsite 136 * @param type method type for call site 137 * 138 * @return callsite for a runtime node 139 */ 140 public static CallSite runtimeBootstrap(final MethodHandles.Lookup lookup, final String initialName, final MethodType type) { 141 return new RuntimeCallSite(type, initialName); 142 } 143 144 /** 145 * Returns a dynamic invoker for a specified dynamic operation using the public lookup. You can use this method to 146 * create a method handle that when invoked acts completely as if it were a Nashorn-linked call site. An overview of 147 * available dynamic operations can be found in the 148 * <a href="https://github.com/szegedi/dynalink/wiki/User-Guide-0.6">Dynalink User Guide</a>, but we'll show few 149 * examples here: 150 * <ul> 151 * <li>Get a named property with fixed name: 152 * <pre> 153 * MethodHandle getColor = Boostrap.createDynamicInvoker("dyn:getProp:color", Object.class, Object.class); 154 * Object obj = ...; // somehow obtain the object 155 * Object color = getColor.invokeExact(obj); 156 * </pre> 157 * </li> 158 * <li>Get a named property with variable name: 159 * <pre> 160 * MethodHandle getProperty = Boostrap.createDynamicInvoker("dyn:getElem", Object.class, Object.class, String.class); 161 * Object obj = ...; // somehow obtain the object 162 * Object color = getProperty.invokeExact(obj, "color"); 163 * Object shape = getProperty.invokeExact(obj, "shape"); 164 * MethodHandle getNumProperty = Boostrap.createDynamicInvoker("dyn:getElem", Object.class, Object.class, int.class); 165 * Object elem42 = getNumProperty.invokeExact(obj, 42); 166 * </pre> 167 * </li> 168 * <li>Set a named property with fixed name: 169 * <pre> 170 * MethodHandle setColor = Boostrap.createDynamicInvoker("dyn:setProp:color", void.class, Object.class, Object.class); 171 * Object obj = ...; // somehow obtain the object 172 * setColor.invokeExact(obj, Color.BLUE); 173 * </pre> 174 * </li> 175 * <li>Set a property with variable name: 176 * <pre> 177 * MethodHandle setProperty = Boostrap.createDynamicInvoker("dyn:setElem", void.class, Object.class, String.class, Object.class); 178 * Object obj = ...; // somehow obtain the object 179 * setProperty.invokeExact(obj, "color", Color.BLUE); 180 * setProperty.invokeExact(obj, "shape", Shape.CIRCLE); 181 * </pre> 182 * </li> 183 * <li>Call a function on an object; two-step variant. This is the actual variant used by Nashorn-generated code: 184 * <pre> 185 * MethodHandle findFooFunction = Boostrap.createDynamicInvoker("dyn:getMethod:foo", Object.class, Object.class); 186 * Object obj = ...; // somehow obtain the object 187 * Object foo_fn = findFooFunction.invokeExact(obj); 188 * MethodHandle callFunctionWithTwoArgs = Boostrap.createDynamicInvoker("dyn:call", Object.class, Object.class, Object.class, Object.class, Object.class); 189 * // Note: "call" operation takes a function, then a "this" value, then the arguments: 190 * Object foo_retval = callFunctionWithTwoArgs.invokeExact(foo_fn, obj, arg1, arg2); 191 * </pre> 192 * </li> 193 * <li>Call a function on an object; single-step variant. Although Nashorn doesn't use this variant and never 194 * emits any INVOKEDYNAMIC instructions with {@code dyn:getMethod}, it still supports this standard Dynalink 195 * operation: 196 * <pre> 197 * MethodHandle callFunctionFooWithTwoArgs = Boostrap.createDynamicInvoker("dyn:callMethod:foo", Object.class, Object.class, Object.class, Object.class); 198 * Object obj = ...; // somehow obtain the object 199 * Object foo_retval = callFunctionFooWithTwoArgs.invokeExact(obj, arg1, arg2); 200 * </pre> 201 * </li> 202 * </ul> 203 * Few additional remarks: 204 * <ul> 205 * <li>Just as Nashorn works with any Java object, the invokers returned from this method can also be applied to 206 * arbitrary Java objects in addition to Nashorn JavaScript objects.</li> 207 * <li>For invoking a named function on an object, you can also use the {@link InvokeByName} convenience class.</li> 208 * <li>For Nashorn objects {@code getElem}, {@code getProp}, and {@code getMethod} are handled almost identically, 209 * since JavaScript doesn't distinguish between different kinds of properties on an object. Either can be used with 210 * fixed property name or a variable property name. The only significant difference is handling of missing 211 * properties: {@code getMethod} for a missing member will link to a potential invocation of 212 * {@code __noSuchMethod__} on the object, {@code getProp} for a missing member will link to a potential invocation 213 * of {@code __noSuchProperty__}, while {@code getElem} for a missing member will link to an empty getter.</li> 214 * <li>In similar vein, {@code setElem} and {@code setProp} are handled identically on Nashorn objects.</li> 215 * <li>There's no rule that the variable property identifier has to be a {@code String} for {@code getProp/setProp} 216 * and {@code int} for {@code getElem/setElem}. You can declare their type to be {@code int}, {@code double}, 217 * {@code Object}, and so on regardless of the kind of the operation.</li> 218 * <li>You can be as specific in parameter types as you want. E.g. if you know that the receiver of the operation 219 * will always be {@code ScriptObject}, you can pass {@code ScriptObject.class} as its parameter type. If you happen 220 * to link to a method that expects different types, (you can use these invokers on POJOs too, after all, and end up 221 * linking with their methods that have strongly-typed signatures), all necessary conversions allowed by either Java 222 * or JavaScript will be applied: if invoked methods specify either primitive or wrapped Java numeric types, or 223 * {@code String} or {@code boolean/Boolean}, then the parameters might be subjected to standard ECMAScript 224 * {@code ToNumber}, {@code ToString}, and {@code ToBoolean} conversion, respectively. Less obviously, if the 225 * expected parameter type is a SAM type, and you pass a JavaScript function, a proxy object implementing the SAM 226 * type and delegating to the function will be passed. Linkage can often be optimized when linkers have more 227 * specific type information than "everything can be an object".</li> 228 * <li>You can also be as specific in return types as you want. For return types any necessary type conversion 229 * available in either Java or JavaScript will be automatically applied, similar to the process described for 230 * parameters, only in reverse direction: if you specify any either primitive or wrapped Java numeric type, or 231 * {@code String} or {@code boolean/Boolean}, then the return values will be subjected to standard ECMAScript 232 * {@code ToNumber}, {@code ToString}, and {@code ToBoolean} conversion, respectively. Less obviously, if the return 233 * type is a SAM type, and the return value is a JavaScript function, a proxy object implementing the SAM type and 234 * delegating to the function will be returned.</li> 235 * </ul> 236 * @param opDesc Dynalink dynamic operation descriptor. 237 * @param rtype the return type for the operation 238 * @param ptypes the parameter types for the operation 239 * @return MethodHandle for invoking the operation. 240 */ 241 public static MethodHandle createDynamicInvoker(final String opDesc, final Class<?> rtype, final Class<?>... ptypes) { 242 return createDynamicInvoker(opDesc, MethodType.methodType(rtype, ptypes)); 243 } 244 245 /** 246 * Returns a dynamic invoker for a specified dynamic operation using the public lookup. Similar to 247 * {@link #createDynamicInvoker(String, Class, Class...)} but with return and parameter types composed into a 248 * method type in the signature. See the discussion of that method for details. 249 * @param opDesc Dynalink dynamic operation descriptor. 250 * @param type the method type for the operation 251 * @return MethodHandle for invoking the operation. 252 */ 253 public static MethodHandle createDynamicInvoker(final String opDesc, final MethodType type) { 254 return bootstrap(MethodHandles.publicLookup(), opDesc, type, 0).dynamicInvoker(); 255 } 256 257 /** 258 * Binds a bean dynamic method (returned by invoking {@code dyn:getMethod} on an object linked with 259 * {@code BeansLinker} to a receiver. 260 * @param dynamicMethod the dynamic method to bind 261 * @param boundThis the bound "this" value. 262 * @return a bound dynamic method. 263 */ 264 public static Object bindDynamicMethod(Object dynamicMethod, Object boundThis) { 265 return new BoundDynamicMethod(dynamicMethod, boundThis); 266 } 267 268 /** 269 * Creates a super-adapter for an adapter, that is, an adapter to the adapter that allows invocation of superclass 270 * methods on it. 271 * @param adapter the original adapter 272 * @return a new adapter that can be used to invoke super methods on the original adapter. 273 */ 274 public static Object createSuperAdapter(final Object adapter) { 275 return new JavaSuperAdapter(adapter); 276 } 277 278 /** 279 * If the given class is a reflection-specific class (anything in {@code java.lang.reflect} and 280 * {@code java.lang.invoke} package, as well a {@link Class} and any subclass of {@link ClassLoader}) and there is 281 * a security manager in the system, then it checks the {@code nashorn.JavaReflection} {@code RuntimePermission}. 282 * @param clazz the class being tested 283 * @param isStatic is access checked for static members (or instance members) 284 */ 285 public static void checkReflectionAccess(Class<?> clazz, boolean isStatic) { 286 ReflectionCheckLinker.checkReflectionAccess(clazz, isStatic); 287 } 288 289 /** 290 * Returns the Nashorn's internally used dynamic linker's services object. Note that in code that is processing a 291 * linking request, you will normally use the {@code LinkerServices} object passed by whatever top-level linker 292 * invoked the linking (if the call site is in Nashorn-generated code, you'll get this object anyway). You should 293 * only resort to retrieving a linker services object using this method when you need some linker services (e.g. 294 * type converter method handles) outside of a code path that is linking a call site. 295 * @return Nashorn's internal dynamic linker's services object. 296 */ 297 public static LinkerServices getLinkerServices() { 298 return dynamicLinker.getLinkerServices(); 299 } 300 301 /** 302 * Takes a guarded invocation, and ensures its method and guard conform to the type of the call descriptor, using 303 * all type conversions allowed by the linker's services. This method is used by Nashorn's linkers as a last step 304 * before returning guarded invocations to the callers. Most of the code used to produce the guarded invocations 305 * does not make an effort to coordinate types of the methods, and so a final type adjustment before a guarded 306 * invocation is returned is the responsibility of the linkers themselves. 307 * @param inv the guarded invocation that needs to be type-converted. Can be null. 308 * @param linkerServices the linker services object providing the type conversions. 309 * @param desc the call site descriptor to whose method type the invocation needs to conform. 310 * @return the type-converted guarded invocation. If input is null, null is returned. If the input invocation 311 * already conforms to the requested type, it is returned unchanged. 312 */ 313 static GuardedInvocation asType(final GuardedInvocation inv, final LinkerServices linkerServices, final CallSiteDescriptor desc) { 314 return inv == null ? null : inv.asType(linkerServices, desc.getMethodType()); 315 } 316 } --- EOF ---