/*
* 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 static jdk.nashorn.internal.lookup.Lookup.MH;
import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.util.HashMap;
import java.util.Map;
import java.util.function.Supplier;
import jdk.dynalink.CallSiteDescriptor;
import jdk.dynalink.NamedOperation;
import jdk.dynalink.Operation;
import jdk.dynalink.beans.BeansLinker;
import jdk.dynalink.linker.GuardedInvocation;
import jdk.dynalink.linker.GuardingDynamicLinker;
import jdk.dynalink.linker.GuardingTypeConverterFactory;
import jdk.dynalink.linker.LinkRequest;
import jdk.dynalink.linker.LinkerServices;
import jdk.dynalink.linker.support.Lookup;
import jdk.nashorn.internal.codegen.types.Type;
import jdk.nashorn.internal.runtime.ECMAException;
import jdk.nashorn.internal.runtime.JSType;
import jdk.nashorn.internal.runtime.ScriptRuntime;
import jdk.nashorn.internal.runtime.UnwarrantedOptimismException;
/**
* Nashorn bottom linker; used as a last-resort catch-all linker for all linking requests that fall through all other
* linkers (see how {@link Bootstrap} class configures the dynamic linker in its static initializer). It will throw
* appropriate ECMAScript errors for attempts to invoke operations on {@code null}, link no-op property getters and
* setters for Java objects that couldn't be linked by any other linker, and throw appropriate ECMAScript errors for
* attempts to invoke arbitrary Java objects as functions or constructors.
*/
final class NashornBottomLinker implements GuardingDynamicLinker, GuardingTypeConverterFactory {
@Override
public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices)
throws Exception {
final Object self = linkRequest.getReceiver();
if (self == null) {
return linkNull(linkRequest);
}
// None of the objects that can be linked by NashornLinker should ever reach here. Basically, anything below
// this point is a generic Java bean. Therefore, reaching here with a ScriptObject is a Nashorn bug.
assert isExpectedObject(self) : "Couldn't link " + linkRequest.getCallSiteDescriptor() + " for " + self.getClass().getName();
return linkBean(linkRequest);
}
private static final MethodHandle EMPTY_PROP_GETTER =
MH.dropArguments(MH.constant(Object.class, UNDEFINED), 0, Object.class);
private static final MethodHandle EMPTY_ELEM_GETTER =
MH.dropArguments(EMPTY_PROP_GETTER, 0, Object.class);
private static final MethodHandle EMPTY_PROP_SETTER =
MH.asType(EMPTY_ELEM_GETTER, EMPTY_ELEM_GETTER.type().changeReturnType(void.class));
private static final MethodHandle EMPTY_ELEM_SETTER =
MH.dropArguments(EMPTY_PROP_SETTER, 0, Object.class);
private static final MethodHandle THROW_STRICT_PROPERTY_SETTER;
private static final MethodHandle THROW_OPTIMISTIC_UNDEFINED;
static {
final Lookup lookup = new Lookup(MethodHandles.lookup());
THROW_STRICT_PROPERTY_SETTER = lookup.findOwnStatic("throwStrictPropertySetter", void.class, Object.class, Object.class);
THROW_OPTIMISTIC_UNDEFINED = lookup.findOwnStatic("throwOptimisticUndefined", Object.class, int.class);
}
private static GuardedInvocation linkBean(final LinkRequest linkRequest) throws Exception {
final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
final Object self = linkRequest.getReceiver();
switch (NashornCallSiteDescriptor.getStandardOperation(desc)) {
case NEW:
if(BeansLinker.isDynamicConstructor(self)) {
throw typeError("no.constructor.matches.args", ScriptRuntime.safeToString(self));
}
if(BeansLinker.isDynamicMethod(self)) {
throw typeError("method.not.constructor", ScriptRuntime.safeToString(self));
}
throw typeError("not.a.function", NashornCallSiteDescriptor.getFunctionErrorMessage(desc, self));
case CALL:
if(BeansLinker.isDynamicConstructor(self)) {
throw typeError("constructor.requires.new", ScriptRuntime.safeToString(self));
}
if(BeansLinker.isDynamicMethod(self)) {
throw typeError("no.method.matches.args", ScriptRuntime.safeToString(self));
}
throw typeError("not.a.function", NashornCallSiteDescriptor.getFunctionErrorMessage(desc, self));
default:
// Everything else is supposed to have been already handled by Bootstrap.beansLinker
// delegating to linkNoSuchBeanMember
throw new AssertionError("unknown call type " + desc);
}
}
static MethodHandle linkMissingBeanMember(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
final String operand = NashornCallSiteDescriptor.getOperand(desc);
switch (NashornCallSiteDescriptor.getStandardOperation(desc)) {
case GET:
if (NashornCallSiteDescriptor.isOptimistic(desc)) {
return adaptThrower(MethodHandles.insertArguments(THROW_OPTIMISTIC_UNDEFINED, 0, NashornCallSiteDescriptor.getProgramPoint(desc)), desc);
} else if (operand != null) {
return getInvocation(EMPTY_PROP_GETTER, linkerServices, desc);
}
return getInvocation(EMPTY_ELEM_GETTER, linkerServices, desc);
case SET:
final boolean strict = NashornCallSiteDescriptor.isStrict(desc);
if (strict) {
return adaptThrower(bindOperand(THROW_STRICT_PROPERTY_SETTER, operand), desc);
} else if (operand != null) {
return getInvocation(EMPTY_PROP_SETTER, linkerServices, desc);
}
return getInvocation(EMPTY_ELEM_SETTER, linkerServices, desc);
default:
throw new AssertionError("unknown call type " + desc);
}
}
private static MethodHandle bindOperand(final MethodHandle handle, final String operand) {
return operand == null ? handle : MethodHandles.insertArguments(handle, 1, operand);
}
private static MethodHandle adaptThrower(final MethodHandle handle, final CallSiteDescriptor desc) {
final MethodType targetType = desc.getMethodType();
final int paramCount = handle.type().parameterCount();
return MethodHandles
.dropArguments(handle, paramCount, targetType.parameterList().subList(paramCount, targetType.parameterCount()))
.asType(targetType);
}
@SuppressWarnings("unused")
private static void throwStrictPropertySetter(final Object self, final Object name) {
throw createTypeError(self, name, "cant.set.property");
}
private static ECMAException createTypeError(final Object self, final Object name, final String msg) {
return typeError(msg, String.valueOf(name), ScriptRuntime.safeToString(self));
}
@SuppressWarnings("unused")
private static Object throwOptimisticUndefined(final int programPoint) {
throw new UnwarrantedOptimismException(UNDEFINED, programPoint, Type.OBJECT);
}
@Override
public GuardedInvocation convertToType(final Class<?> sourceType, final Class<?> targetType, final Supplier<MethodHandles.Lookup> lookupSupplier) throws Exception {
final GuardedInvocation gi = convertToTypeNoCast(sourceType, targetType);
return gi == null ? null : gi.asType(MH.type(targetType, sourceType));
}
/**
* Main part of the implementation of {@link GuardingTypeConverterFactory#convertToType} that doesn't
* care about adapting the method signature; that's done by the invoking method. Returns conversion
* from Object to String/number/boolean (JS primitive types).
* @param sourceType the source type
* @param targetType the target type
* @return a guarded invocation that converts from the source type to the target type.
* @throws Exception if something goes wrong
*/
private static GuardedInvocation convertToTypeNoCast(final Class<?> sourceType, final Class<?> targetType) throws Exception {
final MethodHandle mh = CONVERTERS.get(targetType);
if (mh != null) {
return new GuardedInvocation(mh);
}
return null;
}
private static MethodHandle getInvocation(final MethodHandle handle, final LinkerServices linkerServices, final CallSiteDescriptor desc) {
return linkerServices.asTypeLosslessReturn(handle, desc.getMethodType());
}
// Used solely in an assertion to figure out if the object we get here is something we in fact expect. Objects
// linked by NashornLinker should never reach here.
private static boolean isExpectedObject(final Object obj) {
return !(NashornLinker.canLinkTypeStatic(obj.getClass()));
}
private static GuardedInvocation linkNull(final LinkRequest linkRequest) {
final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
switch (NashornCallSiteDescriptor.getStandardOperation(desc)) {
case NEW:
case CALL:
throw typeError("not.a.function", "null");
case GET:
throw typeError(NashornCallSiteDescriptor.isMethodFirstOperation(desc) ? "no.such.function" : "cant.get.property", getArgument(linkRequest), "null");
case SET:
throw typeError("cant.set.property", getArgument(linkRequest), "null");
default:
throw new AssertionError("unknown call type " + desc);
}
}
private static final Map<Class<?>, MethodHandle> CONVERTERS = new HashMap<>();
static {
CONVERTERS.put(boolean.class, JSType.TO_BOOLEAN.methodHandle());
CONVERTERS.put(double.class, JSType.TO_NUMBER.methodHandle());
CONVERTERS.put(int.class, JSType.TO_INTEGER.methodHandle());
CONVERTERS.put(long.class, JSType.TO_LONG.methodHandle());
CONVERTERS.put(String.class, JSType.TO_STRING.methodHandle());
}
private static String getArgument(final LinkRequest linkRequest) {
final Operation op = linkRequest.getCallSiteDescriptor().getOperation();
if (op instanceof NamedOperation) {
return ((NamedOperation)op).getName().toString();
}
return ScriptRuntime.safeToString(linkRequest.getArguments()[1]);
}
}