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/*
* 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;
import static jdk.nashorn.internal.runtime.ECMAErrors.referenceError;
import static jdk.nashorn.internal.lookup.Lookup.MH;
import java.lang.invoke.MethodHandle;
import jdk.internal.dynalink.CallSiteDescriptor;
import jdk.internal.dynalink.linker.GuardedInvocation;
import jdk.nashorn.internal.codegen.ObjectClassGenerator;
import jdk.nashorn.internal.lookup.Lookup;
import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor;
import jdk.nashorn.internal.runtime.linker.NashornGuards;
/**
* Instances of this class are quite ephemeral; they only exist for the duration of an invocation of
* {@link ScriptObject#findSetMethod(CallSiteDescriptor, jdk.internal.dynalink.linker.LinkRequest)} and
* serve as the actual encapsulation of the algorithm for creating an appropriate property setter method.
*/
final class SetMethodCreator {
// See constructor parameters for description of fields
private final ScriptObject sobj;
private final PropertyMap map;
private final FindProperty find;
private final CallSiteDescriptor desc;
/**
* Creates a new property setter method creator.
* @param sobj the object for which we're creating the property setter
* @param find a result of a {@link ScriptObject#findProperty(String, boolean)} on the object for the property we
* want to create a setter for. Can be null if the property does not yet exist on the object.
* @param desc the descriptor of the call site that triggered the property setter lookup
*/
SetMethodCreator(final ScriptObject sobj, final FindProperty find, final CallSiteDescriptor desc) {
this.sobj = sobj;
this.map = sobj.getMap();
this.find = find;
this.desc = desc;
}
private String getName() {
return desc.getNameToken(CallSiteDescriptor.NAME_OPERAND);
}
private PropertyMap getMap() {
return map;
}
/**
* Creates the actual guarded invocation that represents the dynamic setter method for the property.
* @return the actual guarded invocation that represents the dynamic setter method for the property.
*/
GuardedInvocation createGuardedInvocation() {
return createSetMethod().createGuardedInvocation();
}
/**
* This class encapsulates the results of looking up a setter method; it's basically a triple of a method hanle,
* a Property object, and flags for invocation.
*
*/
private class SetMethod {
private final MethodHandle methodHandle;
private final Property property;
/**
* Creates a new lookup result.
* @param methodHandle the actual method handle
* @param property the property object. Can be null in case we're creating a new property in the global object.
*/
SetMethod(final MethodHandle methodHandle, final Property property) {
assert methodHandle != null;
this.methodHandle = methodHandle;
this.property = property;
}
/**
* Composes from its components an actual guarded invocation that represents the dynamic setter method for the property.
* @return the composed guarded invocation that represents the dynamic setter method for the property.
*/
GuardedInvocation createGuardedInvocation() {
return new GuardedInvocation(methodHandle, getGuard());
}
private MethodHandle getGuard() {
return needsNoGuard() ? null : NashornGuards.getMapGuard(getMap());
}
private boolean needsNoGuard() {
return NashornCallSiteDescriptor.isFastScope(desc) &&
(ObjectClassGenerator.OBJECT_FIELDS_ONLY || isPropertyTypeStable());
}
private boolean isPropertyTypeStable() {
return property == null || !property.canChangeType();
}
}
private SetMethod createSetMethod() {
if (find != null) {
return createExistingPropertySetter();
}
checkStrictCreateNewVariable();
if (sobj.isScope()) {
return createGlobalPropertySetter();
}
return createNewPropertySetter();
}
private void checkStrictCreateNewVariable() {
// In strict mode, assignment can not create a new variable.
// See also ECMA Annex C item 4. ReferenceError is thrown.
if (NashornCallSiteDescriptor.isScope(desc) && NashornCallSiteDescriptor.isStrict(desc)) {
throw referenceError("not.defined", getName());
}
}
private SetMethod createExistingPropertySetter() {
final Property property = find.getProperty();
final Class<?> type = desc.getMethodType().parameterType(1);
final MethodHandle methodHandle = find.getSetter(type, NashornCallSiteDescriptor.isStrict(desc));
assert methodHandle != null;
assert property != null;
final MethodHandle boundHandle;
if (!property.hasSetterFunction() && find.isInherited()) {
boundHandle = ScriptObject.bindTo(methodHandle, find.getOwner());
} else {
boundHandle = methodHandle;
}
return new SetMethod(boundHandle, property);
}
private SetMethod createGlobalPropertySetter() {
final ScriptObject global = Context.getGlobalTrusted();
return new SetMethod(ScriptObject.bindTo(global.addSpill(getName()), global), null);
}
private SetMethod createNewPropertySetter() {
final SetMethod sm = map.getFieldCount() < map.getFieldMaximum() ? createNewFieldSetter() : createNewSpillPropertySetter();
sobj.notifyPropertyAdded(sobj, sm.property);
return sm;
}
private SetMethod createNewFieldSetter() {
final PropertyMap oldMap = getMap();
final Property property = new AccessorProperty(getName(), 0, sobj.getClass(), oldMap.getFieldCount());
final PropertyMap newMap = oldMap.addProperty(property);
MethodHandle setter = MH.insertArguments(ScriptObject.SETFIELD, 0, desc, oldMap, newMap, property.getSetter(Object.class, newMap));
return new SetMethod(MH.asType(setter, Lookup.SET_OBJECT_TYPE), property);
}
private SetMethod createNewSpillPropertySetter() {
final int nextSpill = getMap().getSpillLength();
final Property property = createSpillProperty(nextSpill);
return new SetMethod(createSpillMethodHandle(nextSpill, property), property);
}
private Property createSpillProperty(final int nextSpill) {
final MethodHandle getter = MH.asType(MH.insertArguments(MH.arrayElementGetter(Object[].class), 1, nextSpill), Lookup.GET_OBJECT_TYPE);
final MethodHandle setter = MH.asType(MH.insertArguments(MH.arrayElementSetter(Object[].class), 1, nextSpill), Lookup.SET_OBJECT_TYPE);
return new AccessorProperty(getName(), Property.IS_SPILL, nextSpill, getter, setter);
}
private MethodHandle createSpillMethodHandle(final int nextSpill, Property property) {
final PropertyMap oldMap = getMap();
final PropertyMap newMap = getNewMap(property);
final Object[] spill = sobj.spill;
if (spill == null) {
return MH.insertArguments(ScriptObject.SETSPILLWITHNEW, 0, desc, oldMap, newMap, nextSpill);
} else if (nextSpill < spill.length) {
return MH.insertArguments(ScriptObject.SETSPILL, 0, desc, oldMap, newMap, nextSpill);
} else {
final int newLength = (nextSpill + ScriptObject.SPILL_RATE) / ScriptObject.SPILL_RATE * ScriptObject.SPILL_RATE;
return MH.insertArguments(ScriptObject.SETSPILLWITHGROW, 0, desc, oldMap, newMap, nextSpill, newLength);
}
}
private PropertyMap getNewMap(Property property) {
return getMap().addProperty(property);
}
}
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