--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/src/jdk/nashorn/internal/runtime/linker/NashornBeansLinker.java Fri Nov 01 15:36:33 2013 +0100
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2010, 2013, 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 java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import jdk.internal.dynalink.beans.BeansLinker;
+import jdk.internal.dynalink.linker.ConversionComparator.Comparison;
+import jdk.internal.dynalink.linker.GuardedInvocation;
+import jdk.internal.dynalink.linker.GuardingDynamicLinker;
+import jdk.internal.dynalink.linker.LinkRequest;
+import jdk.internal.dynalink.linker.LinkerServices;
+import jdk.internal.dynalink.support.Lookup;
+import jdk.nashorn.internal.runtime.ConsString;
+
+/**
+ * This linker delegates to a {@code BeansLinker} but passes it a special linker services object that has a modified
+ * {@code asType} method that will ensure that we never pass internal engine objects that should not be externally
+ * observable (currently only ConsString) to Java APIs, but rather that we flatten it into a String. We can't just add
+ * this functionality as custom converters via {@code GuaardingTypeConverterFactory}, since they are not consulted when
+ * the target method handle parameter signature is {@code Object}.
+ */
+public class NashornBeansLinker implements GuardingDynamicLinker {
+ private static final MethodHandle EXPORT_ARGUMENT = new Lookup(MethodHandles.lookup()).findOwnStatic("exportArgument", Object.class, Object.class);
+
+ private final BeansLinker beansLinker = new BeansLinker();
+
+ @Override
+ public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
+ return getGuardedInvocation(beansLinker, linkRequest, linkerServices);
+ }
+
+ /**
+ * Delegates to the specified linker but injects its linker services wrapper so that it will apply all special
+ * conversions that this class does.
+ * @param delegateLinker the linker to which the actual work is delegated to.
+ * @param linkRequest the delegated link request
+ * @param linkerServices the original link services that will be augmented with special conversions
+ * @return the guarded invocation from the delegate, possibly augmented with special conversions
+ * @throws Exception if the delegate throws an exception
+ */
+ public static GuardedInvocation getGuardedInvocation(final GuardingDynamicLinker delegateLinker, final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
+ return delegateLinker.getGuardedInvocation(linkRequest, new NashornBeansLinkerServices(linkerServices));
+ }
+
+ @SuppressWarnings("unused")
+ private static Object exportArgument(final Object arg) {
+ return arg instanceof ConsString ? arg.toString() : arg;
+ }
+
+ private static class NashornBeansLinkerServices implements LinkerServices {
+ private final LinkerServices linkerServices;
+
+ NashornBeansLinkerServices(final LinkerServices linkerServices) {
+ this.linkerServices = linkerServices;
+ }
+
+ @Override
+ public MethodHandle asType(final MethodHandle handle, final MethodType fromType) {
+ final MethodHandle typed = linkerServices.asType(handle, fromType);
+
+ final MethodType handleType = handle.type();
+ final int paramCount = handleType.parameterCount();
+ assert fromType.parameterCount() == handleType.parameterCount();
+
+ MethodHandle[] filters = null;
+ for(int i = 0; i < paramCount; ++i) {
+ if(shouldConvert(handleType.parameterType(i), fromType.parameterType(i))) {
+ if(filters == null) {
+ filters = new MethodHandle[paramCount];
+ }
+ filters[i] = EXPORT_ARGUMENT;
+ }
+ }
+
+ return filters != null ? MethodHandles.filterArguments(typed, 0, filters) : typed;
+ }
+
+ private static boolean shouldConvert(final Class<?> handleType, final Class<?> fromType) {
+ return handleType == Object.class && fromType == Object.class;
+ }
+
+ @Override
+ public MethodHandle getTypeConverter(final Class<?> sourceType, final Class<?> targetType) {
+ return linkerServices.getTypeConverter(sourceType, targetType);
+ }
+
+ @Override
+ public boolean canConvert(final Class<?> from, final Class<?> to) {
+ return linkerServices.canConvert(from, to);
+ }
+
+ @Override
+ public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest) throws Exception {
+ return linkerServices.getGuardedInvocation(linkRequest);
+ }
+
+ @Override
+ public Comparison compareConversion(final Class<?> sourceType, final Class<?> targetType1, final Class<?> targetType2) {
+ return linkerServices.compareConversion(sourceType, targetType1, targetType2);
+ }
+ }
+}