1 /*
2 * Copyright (c) 2016, 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.objects;
27
28 import java.lang.invoke.MethodHandle;
29 import java.util.function.Consumer;
30 import jdk.nashorn.internal.objects.annotations.Attribute;
31 import jdk.nashorn.internal.objects.annotations.Function;
32 import jdk.nashorn.internal.objects.annotations.ScriptClass;
33 import jdk.nashorn.internal.runtime.JSType;
34 import jdk.nashorn.internal.runtime.PropertyMap;
35 import jdk.nashorn.internal.runtime.ScriptObject;
36 import jdk.nashorn.internal.runtime.ScriptRuntime;
37 import jdk.nashorn.internal.runtime.linker.Bootstrap;
38 import jdk.nashorn.internal.runtime.linker.InvokeByName;
39 import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor;
40
41 import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
42
43 /**
44 * ECMA6 25.1.2 The %IteratorPrototype% Object
45 */
46 @ScriptClass("Iterator")
47 public abstract class AbstractIterator extends ScriptObject {
48
49 // initialized by nasgen
50 private static PropertyMap $nasgenmap$;
51
52 private final static Object ITERATOR_INVOKER_KEY = new Object();
53 private final static Object NEXT_INVOKER_KEY = new Object();
54 private final static Object DONE_INVOKER_KEY = new Object();
55 private final static Object VALUE_INVOKER_KEY = new Object();
56
57 /** ECMA6 iteration kinds */
58 enum IterationKind {
59 /** key iteration */
60 KEY,
61 /** value iteration */
62 VALUE,
63 /** key+value iteration */
64 KEY_VALUE
65 }
66
67 /**
68 * Create an abstract iterator object with the given prototype and property map.
69 *
70 * @param prototype the prototype
71 * @param map the property map
72 */
73 protected AbstractIterator(final ScriptObject prototype, final PropertyMap map) {
74 super(prototype, map);
75 }
76
77 /**
78 * 25.1.2.1 %IteratorPrototype% [ @@iterator ] ( )
79 *
80 * @param self the self object
81 * @return this iterator
82 */
83 @Function(attributes = Attribute.NOT_ENUMERABLE, name = "@@iterator")
84 public static Object getIterator(final Object self) {
85 return self;
86 }
87
88 @Override
89 public String getClassName() {
90 return "Iterator";
91 }
92
93 /**
94 * ES6 25.1.1.2 The Iterator Interface
95 *
96 * @param arg argument
97 * @return next iterator result
98 */
99 protected abstract IteratorResult next(final Object arg);
100
101 /**
102 * ES6 25.1.1.3 The IteratorResult Interface
103 *
104 * @param value result value
105 * @param done result status
106 * @param global the global object
107 * @return result object
108 */
109 protected IteratorResult makeResult(final Object value, final Boolean done, final Global global) {
110 return new IteratorResult(value, done, global);
111 }
112
113 static MethodHandle getIteratorInvoker(final Global global) {
114 return global.getDynamicInvoker(ITERATOR_INVOKER_KEY,
115 () -> Bootstrap.createDynamicCallInvoker(Object.class, Object.class, Object.class));
116 }
117
118 /**
119 * Get the invoker for the ES6 iterator {@code next} method.
120 * @param global the global object
121 * @return the next invoker
122 */
123 public static InvokeByName getNextInvoker(final Global global) {
124 return global.getInvokeByName(AbstractIterator.NEXT_INVOKER_KEY,
125 () -> new InvokeByName("next", Object.class, Object.class, Object.class));
126 }
127
128 /**
129 * Get the invoker for the ES6 iterator result {@code done} property.
130 * @param global the global object
131 * @return the done invoker
132 */
133 public static MethodHandle getDoneInvoker(final Global global) {
134 return global.getDynamicInvoker(AbstractIterator.DONE_INVOKER_KEY,
135 () -> Bootstrap.createDynamicInvoker("done", NashornCallSiteDescriptor.GET_PROPERTY, Object.class, Object.class));
136 }
137
138 /**
139 * Get the invoker for the ES6 iterator result {@code value} property.
140 * @param global the global object
141 * @return the value invoker
142 */
143 public static MethodHandle getValueInvoker(final Global global) {
144 return global.getDynamicInvoker(AbstractIterator.VALUE_INVOKER_KEY,
145 () -> Bootstrap.createDynamicInvoker("value", NashornCallSiteDescriptor.GET_PROPERTY, Object.class, Object.class));
146 }
147
148 /**
149 * ES6 7.4.1 GetIterator abstract operation
150 *
151 * @param iterable an object
152 * @param global the global object
153 * @return the iterator
154 */
155 public static Object getIterator(final Object iterable, final Global global) {
156 final Object object = Global.toObject(iterable);
157
158 if (object instanceof ScriptObject) {
159 // TODO we need to implement fast property access for Symbol keys in order to use InvokeByName here.
160 final Object getter = ((ScriptObject) object).get(NativeSymbol.iterator);
161
162 if (Bootstrap.isCallable(getter)) {
163 try {
164 final MethodHandle invoker = getIteratorInvoker(global);
165
166 final Object value = invoker.invokeExact(getter, iterable);
167 if (JSType.isPrimitive(value)) {
168 throw typeError("not.an.object", ScriptRuntime.safeToString(value));
169 }
170 return value;
171
172 } catch (final Throwable t) {
173 throw new RuntimeException(t);
174 }
175 }
176 throw typeError("not.a.function", ScriptRuntime.safeToString(getter));
177 }
178
179 throw typeError("cannot.get.iterator", ScriptRuntime.safeToString(iterable));
180 }
181
182 /**
183 * Iterate over an iterable object, passing every value to {@code consumer}.
184 *
185 * @param iterable an iterable object
186 * @param global the current global
187 * @param consumer the value consumer
188 */
189 public static void iterate(final Object iterable, final Global global, final Consumer<Object> consumer) {
190
191 final Object iterator = AbstractIterator.getIterator(Global.toObject(iterable), global);
192
193 final InvokeByName nextInvoker = getNextInvoker(global);
194 final MethodHandle doneInvoker = getDoneInvoker(global);
195 final MethodHandle valueInvoker = getValueInvoker(global);
196
197 try {
198 do {
199 final Object next = nextInvoker.getGetter().invokeExact(iterator);
200 if (!Bootstrap.isCallable(next)) {
201 break;
202 }
203
204 final Object result = nextInvoker.getInvoker().invokeExact(next, iterator, (Object) null);
205 if (!(result instanceof ScriptObject)) {
206 break;
207 }
208
209 final Object done = doneInvoker.invokeExact(result);
210 if (JSType.toBoolean(done)) {
211 break;
212 }
213
214 consumer.accept(valueInvoker.invokeExact(result));
215
216 } while (true);
217
218 } catch (final RuntimeException r) {
219 throw r;
220 } catch (final Throwable t) {
221 throw new RuntimeException(t);
222 }
223
224 }
225 }
226
227