--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/src/jdk/nashorn/internal/runtime/linker/Bootstrap.java Fri Dec 21 16:36:24 2012 -0400
@@ -0,0 +1,208 @@
+/*
+ * Copyright (c) 2010, 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.nashorn.internal.runtime.linker;
+
+import static jdk.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup;
+
+import java.lang.invoke.CallSite;
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles.Lookup;
+import java.lang.invoke.MethodType;
+import jdk.nashorn.internal.codegen.CompilerConstants.Call;
+import jdk.nashorn.internal.runtime.options.Options;
+import org.dynalang.dynalink.CallSiteDescriptor;
+import org.dynalang.dynalink.DynamicLinker;
+import org.dynalang.dynalink.DynamicLinkerFactory;
+import org.dynalang.dynalink.beans.BeansLinker;
+import org.dynalang.dynalink.linker.GuardedInvocation;
+import org.dynalang.dynalink.linker.LinkerServices;
+
+/**
+ * This class houses bootstrap method for invokedynamic instructions generated by compiler.
+ */
+public final class Bootstrap {
+ /** Reference to the seed boostrap function */
+ public static final Call BOOTSTRAP = staticCallNoLookup(Bootstrap.class, "bootstrap", CallSite.class, Lookup.class, String.class, MethodType.class, int.class);
+
+ // do not create me!!
+ private Bootstrap() {
+ }
+
+ private static final DynamicLinker dynamicLinker;
+ static {
+ final DynamicLinkerFactory factory = new DynamicLinkerFactory();
+ factory.setPrioritizedLinkers(new NashornLinker(), new NashornPrimitiveLinker(), new JSObjectLinker());
+ factory.setFallbackLinkers(new BeansLinker(), new NashornBottomLinker());
+ factory.setSyncOnRelink(true);
+ final int relinkThreshold = Options.getIntProperty("nashorn.unstable.relink.threshold", -1);
+ if (relinkThreshold > -1) {
+ factory.setUnstableRelinkThreshold(relinkThreshold);
+ }
+ dynamicLinker = factory.createLinker();
+ }
+
+ /**
+ * Create a call site and link it for Nashorn. This version of the method conforms to the invokedynamic bootstrap
+ * method expected signature and is referenced from Nashorn generated bytecode as the bootstrap method for all
+ * invokedynamic instructions.
+ * @param lookup MethodHandle lookup. Ignored as Nashorn only uses public lookup.
+ * @param opDesc Dynalink dynamic operation descriptor.
+ * @param type Method type.
+ * @param flags flags for call type, trace/profile etc.
+ * @return CallSite with MethodHandle to appropriate method or null if not found.
+ */
+ public static CallSite bootstrap(final Lookup lookup, final String opDesc, final MethodType type, final int flags) {
+ return dynamicLinker.link(LinkerCallSite.newLinkerCallSite(opDesc, type, flags));
+ }
+
+ /**
+ * Return a dynamic invoker for a specified dynamic operation. You can use this method to create a method handle
+ * that when invoked acts completely as if it were a Nashorn-linked call site. An overview of available dynamic
+ * operations can be found in the <a href="https://github.com/szegedi/dynalink/wiki/User-Guide-0.4">Dynalink User Guide</a>,
+ * but we'll show few examples here:
+ * <ul>
+ * <li>Get a named property with fixed name:
+ * <pre>
+ * MethodHandle getColor = Boostrap.createDynamicInvoker("dyn:getProp:color", Object.class, Object.class);
+ * Object obj = ...; // somehow obtain the object
+ * Object color = getColor.invokeExact(obj);
+ * </pre>
+ * </li>
+ * <li>Get a named property with variable name:
+ * <pre>
+ * MethodHandle getProperty = Boostrap.createDynamicInvoker("dyn:getElem", Object.class, Object.class, String.class);
+ * Object obj = ...; // somehow obtain the object
+ * Object color = getProperty.invokeExact(obj, "color");
+ * Object shape = getProperty.invokeExact(obj, "shape");
+ * MethodHandle getNumProperty = Boostrap.createDynamicInvoker("dyn:getElem", Object.class, Object.class, int.class);
+ * Object elem42 = getNumProperty.invokeExact(obj, 42);
+ * </pre>
+ * </li>
+ * <li>Set a named property with fixed name:
+ * <pre>
+ * MethodHandle setColor = Boostrap.createDynamicInvoker("dyn:setProp:color", void.class, Object.class, Object.class);
+ * Object obj = ...; // somehow obtain the object
+ * setColor.invokeExact(obj, Color.BLUE);
+ * </pre>
+ * </li>
+ * <li>Set a property with variable name:
+ * <pre>
+ * MethodHandle setProperty = Boostrap.createDynamicInvoker("dyn:setElem", void.class, Object.class, String.class, Object.class);
+ * Object obj = ...; // somehow obtain the object
+ * setProperty.invokeExact(obj, "color", Color.BLUE);
+ * setProperty.invokeExact(obj, "shape", Shape.CIRCLE);
+ * </pre>
+ * </li>
+ * <li>Call a function on an object; two-step variant. This is the actual variant used by Nashorn-generated code:
+ * <pre>
+ * MethodHandle findFooFunction = Boostrap.createDynamicInvoker("dyn:getMethod:foo", Object.class, Object.class);
+ * Object obj = ...; // somehow obtain the object
+ * Object foo_fn = findFooFunction.invokeExact(obj);
+ * MethodHandle callFunctionWithTwoArgs = Boostrap.createDynamicInvoker("dyn:call", Object.class, Object.class, Object.class, Object.class, Object.class);
+ * // Note: "call" operation takes a function, then a "this" value, then the arguments:
+ * Object foo_retval = callFunctionWithTwoArgs.invokeExact(foo_fn, obj, arg1, arg2);
+ * </pre>
+ * </li>
+ * <li>Call a function on an object; single-step variant. Although Nashorn doesn't use this variant and never
+ * emits any INVOKEDYNAMIC instructions with {@code dyn:getMethod}, it still supports this standard Dynalink
+ * operation:
+ * <pre>
+ * MethodHandle callFunctionFooWithTwoArgs = Boostrap.createDynamicInvoker("dyn:callMethod:foo", Object.class, Object.class, Object.class, Object.class);
+ * Object obj = ...; // somehow obtain the object
+ * Object foo_retval = callFunctionFooWithTwoArgs.invokeExact(obj, arg1, arg2);
+ * </pre>
+ * </li>
+ * </ul>
+ * Few additional remarks:
+ * <ul>
+ * <li>Just as Nashorn works with any Java object, the invokers returned from this method can also be applied to
+ * arbitrary Java objects in addition to Nashorn JavaScript objects.</li>
+ * <li>For invoking a named function on an object, you can also use the {@link InvokeByName} convenience class.</li>
+ * <li>For Nashorn objects {@code getElem}, {@code getProp}, and {@code getMethod} are handled almost identically,
+ * since JavaScript doesn't distinguish between different kinds of properties on an object. Either can be used with
+ * fixed property name or a variable property name. The only significant difference is handling of missing
+ * properties: {@code getMethod} for a missing member will link to a potential invocation of
+ * {@code __noSuchMethod__} on the object, {@code getProp} for a missing member will link to a potential invocation
+ * of {@code __noSuchProperty__}, while {@code getElem} for a missing member will link to an empty getter.</li>
+ * <li>In similar vein, {@code setElem} and {@code setProp} are handled identically on Nashorn objects.</li>
+ * <li>There's no rule that the variable property identifier has to be a {@code String} for {@code getProp/setProp}
+ * and {@code int} for {@code getElem/setElem}. You can declare their type to be {@code int}, {@code double},
+ * {@code Object}, and so on regardless of the kind of the operation.</li>
+ * <li>You can be as specific in parameter types as you want. E.g. if you know that the receiver of the operation
+ * will always be {@code ScriptObject}, you can pass {@code ScriptObject.class} as its parameter type. If you happen
+ * to link to a method that expects different types, (you can use these invokers on POJOs too, after all, and end up
+ * linking with their methods that have strongly-typed signatures), all necessary conversions allowed by either Java
+ * or JavaScript will be applied: if invoked methods specify either primitive or wrapped Java numeric types, or
+ * {@code String} or {@code boolean/Boolean}, then the parameters might be subjected to standard ECMAScript
+ * {@code ToNumber}, {@code ToString}, and {@code ToBoolean} conversion, respectively. Less obviously, if the
+ * expected parameter type is a SAM type, and you pass a JavaScript function, a proxy object implementing the SAM
+ * type and delegating to the function will be passed. Linkage can often be optimized when linkers have more
+ * specific type information than "everything can be an object".</li>
+ * <li>You can also be as specific in return types as you want. For return types any necessary type conversion
+ * available in either Java or JavaScript will be automatically applied, similar to the process described for
+ * parameters, only in reverse direction: if you specify any either primitive or wrapped Java numeric type, or
+ * {@code String} or {@code boolean/Boolean}, then the return values will be subjected to standard ECMAScript
+ * {@code ToNumber}, {@code ToString}, and {@code ToBoolean} conversion, respectively. Less obviously, if the return
+ * type is a SAM type, and the return value is a JavaScript function, a proxy object implementing the SAM type and
+ * delegating to the function will be returned.</li>
+ * </ul>
+ * @param opDesc Dynalink dynamic operation descriptor.
+ * @param rtype return type of the operation
+ * @param ptypes parameter types of the operation
+ * @return MethodHandle for invoking the operation.
+ */
+ public static MethodHandle createDynamicInvoker(final String opDesc, final Class<?> rtype, final Class<?>... ptypes) {
+ return bootstrap(null, opDesc, MethodType.methodType(rtype, ptypes), 0).dynamicInvoker();
+ }
+
+ /**
+ * Returns the Nashorn's internally used dynamic linker's services object. Note that in code that is processing a
+ * linking request, you will normally use the {@code LinkerServices} object passed by whatever top-level linker
+ * invoked the linking (if the call site is in Nashorn-generated code, you'll get this object anyway). You should
+ * only resort to retrieving a linker services object using this method when you need some linker services (e.g.
+ * type converter method handles) outside of a code path that is linking a call site.
+ * @return Nashorn's internal dynamic linker's services object.
+ */
+ public static LinkerServices getLinkerServices() {
+ return dynamicLinker.getLinkerServices();
+ }
+
+ /**
+ * Takes a guarded invocation, and ensures its method and guard conform to the type of the call descriptor, using
+ * all type conversions allowed by the linker's services. This method is used by Nashorn's linkers as a last step
+ * before returning guarded invocations to the callers. Most of the code used to produce the guarded invocations
+ * does not make an effort to coordinate types of the methods, and so a final type adjustment before a guarded
+ * invocation is returned is the responsibility of the linkers themselves.
+ * @param inv the guarded invocation that needs to be type-converted. Can be null.
+ * @param linkerServices the linker services object providing the type conversions.
+ * @param desc the call site descriptor to whose method type the invocation needs to conform.
+ * @return the type-converted guarded invocation. If input is null, null is returned. If the input invocation
+ * already conforms to the requested type, it is returned unchanged.
+ */
+ static GuardedInvocation asType(final GuardedInvocation inv, final LinkerServices linkerServices, final CallSiteDescriptor desc) {
+ return inv == null ? null : inv.asType(linkerServices, desc.getMethodType());
+ }
+}