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.codegen.ObjectClassGenerator;
35 import jdk.nashorn.internal.lookup.Lookup;
36 import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor;
37 import jdk.nashorn.internal.runtime.linker.NashornGuards;
38
39
40 /**
41 * Instances of this class are quite ephemeral; they only exist for the duration of an invocation of
42 * {@link ScriptObject#findSetMethod(CallSiteDescriptor, jdk.internal.dynalink.linker.LinkRequest)} and
43 * serve as the actual encapsulation of the algorithm for creating an appropriate property setter method.
44 */
45 final class SetMethodCreator {
46 // See constructor parameters for description of fields
47 private final ScriptObject sobj;
48 private final PropertyMap map;
49 private final FindProperty find;
50 private final CallSiteDescriptor desc;
51
52 /**
53 * Creates a new property setter method creator.
54 * @param sobj the object for which we're creating the property setter
55 * @param find a result of a {@link ScriptObject#findProperty(String, boolean)} on the object for the property we
56 * want to create a setter for. Can be null if the property does not yet exist on the object.
57 * @param desc the descriptor of the call site that triggered the property setter lookup
58 */
59 SetMethodCreator(final ScriptObject sobj, final FindProperty find, final CallSiteDescriptor desc) {
60 this.sobj = sobj;
61 this.map = sobj.getMap();
62 this.find = find;
63 this.desc = desc;
64 }
65
66 private String getName() {
67 return desc.getNameToken(CallSiteDescriptor.NAME_OPERAND);
68 }
69
70 private PropertyMap getMap() {
71 return map;
72 }
73
74 /**
75 * Creates the actual guarded invocation that represents the dynamic setter method for the property.
76 * @return the actual guarded invocation that represents the dynamic setter method for the property.
77 */
78 GuardedInvocation createGuardedInvocation() {
79 return createSetMethod().createGuardedInvocation();
80 }
81
82 /**
83 * This class encapsulates the results of looking up a setter method; it's basically a triple of a method hanle,
84 * a Property object, and flags for invocation.
85 *
86 */
87 private class SetMethod {
88 private final MethodHandle methodHandle;
89 private final Property property;
90
91 /**
92 * Creates a new lookup result.
93 * @param methodHandle the actual method handle
94 * @param property the property object. Can be null in case we're creating a new property in the global object.
95 */
96 SetMethod(final MethodHandle methodHandle, final Property property) {
97 assert methodHandle != null;
98 this.methodHandle = methodHandle;
99 this.property = property;
100 }
101
102 /**
103 * Composes from its components an actual guarded invocation that represents the dynamic setter method for the property.
104 * @return the composed guarded invocation that represents the dynamic setter method for the property.
105 */
106 GuardedInvocation createGuardedInvocation() {
107 return new GuardedInvocation(methodHandle, getGuard());
108 }
109
110 private MethodHandle getGuard() {
111 return needsNoGuard() ? null : NashornGuards.getMapGuard(getMap());
112 }
113
114 private boolean needsNoGuard() {
115 return NashornCallSiteDescriptor.isFastScope(desc) &&
116 (ObjectClassGenerator.OBJECT_FIELDS_ONLY || isPropertyTypeStable());
117 }
118
119 private boolean isPropertyTypeStable() {
120 return property == null || !property.canChangeType();
121 }
122 }
123
124 private SetMethod createSetMethod() {
125 if (find != null) {
126 return createExistingPropertySetter();
127 }
128
129 checkStrictCreateNewVariable();
130
131 if (sobj.isScope()) {
132 return createGlobalPropertySetter();
133 }
134
135 return createNewPropertySetter();
136 }
137
138 private void checkStrictCreateNewVariable() {
139 // In strict mode, assignment can not create a new variable.
140 // See also ECMA Annex C item 4. ReferenceError is thrown.
141 if (NashornCallSiteDescriptor.isScope(desc) && NashornCallSiteDescriptor.isStrict(desc)) {
142 throw referenceError("not.defined", getName());
143 }
144 }
145
146 private SetMethod createExistingPropertySetter() {
147 final Property property = find.getProperty();
148 final Class<?> type = desc.getMethodType().parameterType(1);
149 final MethodHandle methodHandle = find.getSetter(type, NashornCallSiteDescriptor.isStrict(desc));
150
151 assert methodHandle != null;
152 assert property != null;
153
154 final MethodHandle boundHandle;
155 if (!property.hasSetterFunction(find.getOwner()) && find.isInherited()) {
156 // Bind or add prototype filter depending on whether this is a scope object.
157 boundHandle = sobj.isScope() ?
158 ScriptObject.addProtoFilter(methodHandle, find.getProtoChainLength()):
159 ScriptObject.bindTo(methodHandle, find.getOwner());
160 } else {
161 boundHandle = methodHandle;
162 }
163 return new SetMethod(boundHandle, property);
164 }
165
166 private SetMethod createGlobalPropertySetter() {
167 final ScriptObject global = Context.getGlobalTrusted();
168 return new SetMethod(ScriptObject.bindTo(global.addSpill(getName()), global), null);
169 }
170
171 private SetMethod createNewPropertySetter() {
172 final SetMethod sm = map.getFieldCount() < map.getFieldMaximum() ? createNewFieldSetter() : createNewSpillPropertySetter();
173 sobj.notifyPropertyAdded(sobj, sm.property);
174 return sm;
175 }
176
177 private SetMethod createNewFieldSetter() {
178 final PropertyMap oldMap = getMap();
179 final Property property = new AccessorProperty(getName(), 0, sobj.getClass(), oldMap.getFieldCount());
180 final PropertyMap newMap = oldMap.addProperty(property);
181 MethodHandle setter = MH.insertArguments(ScriptObject.SETFIELD, 0, desc, oldMap, newMap, property.getSetter(Object.class, newMap));
182
183 return new SetMethod(MH.asType(setter, Lookup.SET_OBJECT_TYPE), property);
184 }
185
186 private SetMethod createNewSpillPropertySetter() {
187 final int nextSpill = getMap().getSpillLength();
188
189 final Property property = new AccessorProperty(getName(), Property.IS_SPILL, nextSpill);
190 return new SetMethod(createSpillMethodHandle(nextSpill, property), property);
191 }
192
193 private MethodHandle createSpillMethodHandle(final int nextSpill, Property property) {
194 final PropertyMap oldMap = getMap();
195 final PropertyMap newMap = getNewMap(property);
196
197 final Object[] spill = sobj.spill;
198 if (spill == null) {
199 return MH.insertArguments(ScriptObject.SETSPILLWITHNEW, 0, desc, oldMap, newMap, nextSpill);
200 } else if (nextSpill < spill.length) {
201 return MH.insertArguments(ScriptObject.SETSPILL, 0, desc, oldMap, newMap, nextSpill);
202 } else {
203 final int newLength = (nextSpill + ScriptObject.SPILL_RATE) / ScriptObject.SPILL_RATE * ScriptObject.SPILL_RATE;
204 return MH.insertArguments(ScriptObject.SETSPILLWITHGROW, 0, desc, oldMap, newMap, nextSpill, newLength);
205 }
206 }
207
208 private PropertyMap getNewMap(Property property) {
209 return getMap().addProperty(property);
210 }
211 }