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;
  27 
  28 import static jdk.nashorn.internal.runtime.ECMAErrors.referenceError;
  29 import static jdk.nashorn.internal.lookup.Lookup.MH;
  30 
  31 import java.lang.invoke.MethodHandle;
  32 import jdk.internal.dynalink.CallSiteDescriptor;
  33 import jdk.internal.dynalink.linker.GuardedInvocation;
  34 import jdk.nashorn.internal.lookup.Lookup;
  35 import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor;
  36 import jdk.nashorn.internal.runtime.linker.NashornGuards;
  37 
  38 
  39 /**
  40  * Instances of this class are quite ephemeral; they only exist for the duration of an invocation of
  41  * {@link ScriptObject#findSetMethod(CallSiteDescriptor, jdk.internal.dynalink.linker.LinkRequest)} and
  42  * serve as the actual encapsulation of the algorithm for creating an appropriate property setter method.
  43  */
  44 final class SetMethodCreator {
  45     // See constructor parameters for description of fields
  46     private final ScriptObject sobj;
  47     private final PropertyMap map;
  48     private final FindProperty find;
  49     private final CallSiteDescriptor desc;
  50 
  51     /**
  52      * Creates a new property setter method creator.
  53      * @param sobj the object for which we're creating the property setter
  54      * @param find a result of a {@link ScriptObject#findProperty(String, boolean)} on the object for the property we
  55      * want to create a setter for. Can be null if the property does not yet exist on the object.
  56      * @param desc the descriptor of the call site that triggered the property setter lookup
  57      */
  58     SetMethodCreator(final ScriptObject sobj, final FindProperty find, final CallSiteDescriptor desc) {
  59         this.sobj = sobj;
  60         this.map = sobj.getMap();
  61         this.find = find;
  62         this.desc = desc;
  63     }
  64 
  65     private String getName() {
  66         return desc.getNameToken(CallSiteDescriptor.NAME_OPERAND);
  67     }
  68 
  69     private PropertyMap getMap() {
  70         return map;
  71     }
  72 
  73     /**
  74      * Creates the actual guarded invocation that represents the dynamic setter method for the property.
  75      * @return the actual guarded invocation that represents the dynamic setter method for the property.
  76      */
  77     GuardedInvocation createGuardedInvocation() {
  78         return createSetMethod().createGuardedInvocation();
  79     }
  80 
  81     /**
  82      * This class encapsulates the results of looking up a setter method; it's basically a triple of a method handle,
  83      * a Property object, and flags for invocation.
  84      *
  85      */
  86     private class SetMethod {
  87         private final MethodHandle methodHandle;
  88         private final Property property;
  89 
  90         /**
  91          * Creates a new lookup result.
  92          * @param methodHandle the actual method handle
  93          * @param property the property object. Can be null in case we're creating a new property in the global object.
  94          */
  95         SetMethod(final MethodHandle methodHandle, final Property property) {
  96             assert methodHandle != null;
  97             this.methodHandle = methodHandle;
  98             this.property = property;
  99         }
 100 
 101         /**
 102          * Composes from its components an actual guarded invocation that represents the dynamic setter method for the property.
 103          * @return the composed guarded invocation that represents the dynamic setter method for the property.
 104          */
 105         GuardedInvocation createGuardedInvocation() {
 106             return new GuardedInvocation(methodHandle, NashornGuards.getGuard(sobj, property, desc));
 107         }
 108 
 109     }
 110 
 111     private SetMethod createSetMethod() {
 112         if (find != null) {
 113             return createExistingPropertySetter();
 114         }
 115 
 116         checkStrictCreateNewVariable();
 117 
 118         if (sobj.isScope()) {
 119             return createGlobalPropertySetter();
 120         }
 121 
 122         return createNewPropertySetter();
 123     }
 124 
 125     private void checkStrictCreateNewVariable() {
 126         // In strict mode, assignment can not create a new variable.
 127         // See also ECMA Annex C item 4. ReferenceError is thrown.
 128         if (NashornCallSiteDescriptor.isScope(desc) && NashornCallSiteDescriptor.isStrict(desc)) {
 129             throw referenceError("not.defined", getName());
 130         }
 131     }
 132 
 133     private SetMethod createExistingPropertySetter() {
 134         final Property property = find.getProperty();
 135         final Class<?> type = desc.getMethodType().parameterType(1);
 136         final MethodHandle methodHandle = find.getSetter(type, NashornCallSiteDescriptor.isStrict(desc));
 137 
 138         assert methodHandle != null;
 139         assert property     != null;
 140 
 141         final MethodHandle boundHandle;
 142         if (!property.hasSetterFunction(find.getOwner()) && find.isInherited()) {
 143             boundHandle = ScriptObject.addProtoFilter(methodHandle, find.getProtoChainLength());
 144         } else {
 145             boundHandle = methodHandle;
 146         }
 147         return new SetMethod(boundHandle, property);
 148     }
 149 
 150     private SetMethod createGlobalPropertySetter() {
 151         final ScriptObject global = Context.getGlobalTrusted();
 152         return new SetMethod(MH.filterArguments(global.addSpill(getName()), 0, ScriptObject.GLOBALFILTER), null);
 153     }
 154 
 155     private SetMethod createNewPropertySetter() {
 156         final SetMethod sm = map.getFieldCount() < map.getFieldMaximum() ? createNewFieldSetter() : createNewSpillPropertySetter();
 157         final PropertyListeners listeners = map.getListeners();
 158         if (listeners != null) {
 159             listeners.propertyAdded(sm.property);
 160         }
 161         return sm;
 162     }
 163 
 164     private SetMethod createNewFieldSetter() {
 165         final PropertyMap oldMap = getMap();
 166         final Property property = new AccessorProperty(getName(), 0, sobj.getClass(), oldMap.getFieldCount());
 167         final PropertyMap newMap = oldMap.addProperty(property);
 168         MethodHandle setter = MH.insertArguments(ScriptObject.SETFIELD, 0, desc, oldMap, newMap, property.getSetter(Object.class, newMap));
 169 
 170         return new SetMethod(MH.asType(setter, Lookup.SET_OBJECT_TYPE), property);
 171     }
 172 
 173     private SetMethod createNewSpillPropertySetter() {
 174         final int nextSpill = getMap().getSpillLength();
 175 
 176         final Property property = new AccessorProperty(getName(), Property.IS_SPILL, nextSpill);
 177         return new SetMethod(createSpillMethodHandle(nextSpill, property), property);
 178     }
 179 
 180     private MethodHandle createSpillMethodHandle(final int nextSpill, Property property) {
 181         final PropertyMap oldMap = getMap();
 182         final PropertyMap newMap = getNewMap(property);
 183 
 184         final Object[] spill = sobj.spill;
 185         if (spill == null) {
 186             return MH.insertArguments(ScriptObject.SETSPILLWITHNEW,  0, desc, oldMap, newMap, nextSpill);
 187         } else if (nextSpill < spill.length) {
 188             return MH.insertArguments(ScriptObject.SETSPILL,         0, desc, oldMap, newMap, nextSpill);
 189         } else {
 190             final int newLength = (nextSpill + ScriptObject.SPILL_RATE) / ScriptObject.SPILL_RATE * ScriptObject.SPILL_RATE;
 191             return MH.insertArguments(ScriptObject.SETSPILLWITHGROW, 0, desc, oldMap, newMap, nextSpill, newLength);
 192         }
 193     }
 194 
 195     private PropertyMap getNewMap(Property property) {
 196         return getMap().addProperty(property);
 197     }
 198 }