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1   /*
2    * Copyright (c) 2002-2025 Gargoyle Software Inc.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * https://www.apache.org/licenses/LICENSE-2.0
8    *
9    * Unless required by applicable law or agreed to in writing, software
10   * distributed under the License is distributed on an "AS IS" BASIS,
11   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12   * See the License for the specific language governing permissions and
13   * limitations under the License.
14   */
15  package org.htmlunit.javascript;
16  
17  import static org.htmlunit.BrowserVersionFeatures.JS_ERROR_CAPTURE_STACK_TRACE;
18  import static org.htmlunit.BrowserVersionFeatures.JS_ERROR_STACK_TRACE_LIMIT;
19  import static org.htmlunit.BrowserVersionFeatures.JS_ITERATOR_VISIBLE_IN_WINDOW;
20  import static org.htmlunit.BrowserVersionFeatures.JS_WINDOW_INSTALL_TRIGGER_NULL;
21  
22  import java.io.IOException;
23  import java.io.ObjectInputStream;
24  import java.lang.reflect.Member;
25  import java.lang.reflect.Method;
26  import java.net.URL;
27  import java.util.ArrayList;
28  import java.util.HashMap;
29  import java.util.List;
30  import java.util.Map;
31  import java.util.Map.Entry;
32  
33  import org.apache.commons.lang3.StringUtils;
34  import org.apache.commons.logging.Log;
35  import org.apache.commons.logging.LogFactory;
36  import org.htmlunit.BrowserVersion;
37  import org.htmlunit.Page;
38  import org.htmlunit.ScriptException;
39  import org.htmlunit.WebAssert;
40  import org.htmlunit.WebClient;
41  import org.htmlunit.WebWindow;
42  import org.htmlunit.corejs.javascript.Callable;
43  import org.htmlunit.corejs.javascript.Context;
44  import org.htmlunit.corejs.javascript.ContextAction;
45  import org.htmlunit.corejs.javascript.ContextFactory;
46  import org.htmlunit.corejs.javascript.EcmaError;
47  import org.htmlunit.corejs.javascript.Function;
48  import org.htmlunit.corejs.javascript.FunctionObject;
49  import org.htmlunit.corejs.javascript.JavaScriptException;
50  import org.htmlunit.corejs.javascript.NativeArray;
51  import org.htmlunit.corejs.javascript.NativeArrayIterator;
52  import org.htmlunit.corejs.javascript.NativeConsole;
53  import org.htmlunit.corejs.javascript.NativeFunction;
54  import org.htmlunit.corejs.javascript.RhinoException;
55  import org.htmlunit.corejs.javascript.Script;
56  import org.htmlunit.corejs.javascript.ScriptRuntime;
57  import org.htmlunit.corejs.javascript.Scriptable;
58  import org.htmlunit.corejs.javascript.ScriptableObject;
59  import org.htmlunit.corejs.javascript.StackStyle;
60  import org.htmlunit.corejs.javascript.Symbol;
61  import org.htmlunit.corejs.javascript.TopLevel;
62  import org.htmlunit.html.DomNode;
63  import org.htmlunit.html.HtmlPage;
64  import org.htmlunit.javascript.background.BackgroundJavaScriptFactory;
65  import org.htmlunit.javascript.background.JavaScriptExecutor;
66  import org.htmlunit.javascript.configuration.AbstractJavaScriptConfiguration;
67  import org.htmlunit.javascript.configuration.ClassConfiguration;
68  import org.htmlunit.javascript.configuration.ClassConfiguration.ConstantInfo;
69  import org.htmlunit.javascript.configuration.ClassConfiguration.PropertyInfo;
70  import org.htmlunit.javascript.configuration.JavaScriptConfiguration;
71  import org.htmlunit.javascript.configuration.ProxyAutoConfigJavaScriptConfiguration;
72  import org.htmlunit.javascript.host.ConsoleCustom;
73  import org.htmlunit.javascript.host.NumberCustom;
74  import org.htmlunit.javascript.host.URLSearchParams;
75  import org.htmlunit.javascript.host.Window;
76  import org.htmlunit.javascript.host.dom.DOMException;
77  import org.htmlunit.javascript.host.html.HTMLImageElement;
78  import org.htmlunit.javascript.host.html.HTMLOptionElement;
79  import org.htmlunit.javascript.host.intl.Intl;
80  import org.htmlunit.javascript.host.xml.FormData;
81  import org.htmlunit.javascript.polyfill.Polyfill;
82  
83  /**
84   * A wrapper for the <a href="http://www.mozilla.org/rhino">Rhino JavaScript engine</a>
85   * that provides browser specific features.
86   *
87   * <p>Like all classes in this package, this class is not intended for direct use
88   * and may change without notice.</p>
89   *
90   * @author Mike Bowler
91   * @author Chen Jun
92   * @author David K. Taylor
93   * @author Chris Erskine
94   * @author Ben Curren
95   * @author David D. Kilzer
96   * @author Marc Guillemot
97   * @author Daniel Gredler
98   * @author Ahmed Ashour
99   * @author Amit Manjhi
100  * @author Ronald Brill
101  * @author Frank Danek
102  * @author Lai Quang Duong
103  * @author Sven Strickroth
104  *
105  * @see <a href="http://groups-beta.google.com/group/netscape.public.mozilla.jseng/browse_thread/thread/b4edac57329cf49f/069e9307ec89111f">
106  *     Rhino and Java Browser</a>
107  */
108 public class JavaScriptEngine implements AbstractJavaScriptEngine<Script> {
109 
110     private static final Log LOG = LogFactory.getLog(JavaScriptEngine.class);
111 
112     /** ScriptRuntime.emptyArgs. */
113     public static final Object[] EMPTY_ARGS = ScriptRuntime.emptyArgs;
114 
115     /** org.htmlunit.corejs.javascript.Undefined.instance. */
116     public static final Object UNDEFINED = org.htmlunit.corejs.javascript.Undefined.instance;
117 
118     private WebClient webClient_;
119     private HtmlUnitContextFactory contextFactory_;
120     private JavaScriptConfiguration jsConfig_;
121 
122     private transient ThreadLocal<Boolean> javaScriptRunning_;
123     private transient ThreadLocal<List<PostponedAction>> postponedActions_;
124     private transient boolean holdPostponedActions_;
125     private transient boolean shutdownPending_;
126 
127     /** The JavaScriptExecutor corresponding to all windows of this Web client */
128     private transient JavaScriptExecutor javaScriptExecutor_;
129 
130     /**
131      * Key used to place the {@link HtmlPage} for which the JavaScript code is executed
132      * as thread local attribute in current context.
133      */
134     public static final String KEY_STARTING_PAGE = "startingPage";
135 
136     /**
137      * Creates an instance for the specified {@link WebClient}.
138      *
139      * @param webClient the client that will own this engine
140      */
141     public JavaScriptEngine(final WebClient webClient) {
142         if (webClient == null) {
143             throw new IllegalArgumentException("JavaScriptEngine ctor requires a webClient");
144         }
145 
146         webClient_ = webClient;
147         contextFactory_ = new HtmlUnitContextFactory(webClient);
148         initTransientFields();
149 
150         jsConfig_ = JavaScriptConfiguration.getInstance(webClient.getBrowserVersion());
151         RhinoException.setStackStyle(StackStyle.MOZILLA_LF);
152     }
153 
154     /**
155      * Returns the web client that this engine is associated with.
156      * @return the web client
157      */
158     private WebClient getWebClient() {
159         return webClient_;
160     }
161 
162     /**
163      * {@inheritDoc}
164      */
165     @Override
166     public HtmlUnitContextFactory getContextFactory() {
167         return contextFactory_;
168     }
169 
170     /**
171      * Performs initialization for the given webWindow.
172      * @param webWindow the web window to initialize for
173      */
174     @Override
175     public void initialize(final WebWindow webWindow, final Page page) {
176         WebAssert.notNull("webWindow", webWindow);
177 
178         if (shutdownPending_) {
179             return;
180         }
181 
182         getContextFactory().call(cx -> {
183             try {
184                 init(webWindow, page, cx);
185             }
186             catch (final Exception e) {
187                 LOG.error("Exception while initializing JavaScript for the page", e);
188                 throw new ScriptException(null, e); // BUG: null is not useful.
189             }
190             return null;
191         });
192     }
193 
194     /**
195      * Returns the JavaScriptExecutor.
196      * @return the JavaScriptExecutor or null if javascript is disabled
197      *         or no executor was required so far.
198      */
199     public JavaScriptExecutor getJavaScriptExecutor() {
200         return javaScriptExecutor_;
201     }
202 
203     /**
204      * Initializes all the JS stuff for the window.
205      * @param webWindow the web window
206      * @param context the current context
207      * @throws Exception if something goes wrong
208      */
209     private void init(final WebWindow webWindow, final Page page, final Context context) throws Exception {
210         final WebClient webClient = getWebClient();
211         final BrowserVersion browserVersion = webClient.getBrowserVersion();
212 
213         final Window jsWindowScope = new Window();
214         jsWindowScope.setClassName("Window");
215 
216         context.initSafeStandardObjects(jsWindowScope);
217         configureRhino(webClient, browserVersion, jsWindowScope);
218 
219         final Map<Class<? extends Scriptable>, Scriptable> prototypes = new HashMap<>();
220         final Map<String, Scriptable> prototypesPerJSName = new HashMap<>();
221 
222         final ClassConfiguration windowConfig = jsConfig_.getWindowClassConfiguration();
223         final FunctionObject functionObject = new FunctionObject(jsWindowScope.getClassName(),
224                         windowConfig.getJsConstructor().getValue(), jsWindowScope);
225         ScriptableObject.defineProperty(jsWindowScope, "constructor", functionObject,
226                 ScriptableObject.DONTENUM  | ScriptableObject.PERMANENT | ScriptableObject.READONLY);
227 
228         configureConstantsPropertiesAndFunctions(windowConfig, jsWindowScope);
229 
230         final HtmlUnitScriptable windowPrototype = configureClass(windowConfig, jsWindowScope);
231         jsWindowScope.setPrototype(windowPrototype);
232         prototypes.put(windowConfig.getHostClass(), windowPrototype);
233         prototypesPerJSName.put(windowConfig.getClassName(), windowPrototype);
234 
235         configureScope(jsWindowScope, windowConfig, functionObject, jsConfig_, browserVersion, prototypes, prototypesPerJSName);
236 
237         URLSearchParams.NativeParamsIterator.init(jsWindowScope, "URLSearchParams Iterator");
238         FormData.FormDataIterator.init(jsWindowScope, "FormData Iterator");
239 
240         // strange but this is the reality for browsers
241         // because there will be still some sites using this for browser detection the property is
242         // set to null
243         // https://stackoverflow.com/questions/9847580/how-to-detect-safari-chrome-ie-firefox-and-opera-browsers
244         // https://bugzilla.mozilla.org/show_bug.cgi?id=1442035
245         if (browserVersion.hasFeature(JS_WINDOW_INSTALL_TRIGGER_NULL)) {
246             jsWindowScope.put("InstallTrigger", jsWindowScope, null);
247         }
248 
249         // special handling for image/option
250         final Method imageCtor = HTMLImageElement.class.getDeclaredMethod("jsConstructorImage");
251         additionalCtor(jsWindowScope, prototypesPerJSName.get("HTMLImageElement"), imageCtor, "Image", "HTMLImageElement");
252         final Method optionCtor = HTMLOptionElement.class.getDeclaredMethod("jsConstructorOption",
253                 new Class[] {Object.class, String.class, boolean.class, boolean.class});
254         additionalCtor(jsWindowScope, prototypesPerJSName.get("HTMLOptionElement"), optionCtor, "Option", "HTMLOptionElement");
255 
256         if (!webClient.getOptions().isWebSocketEnabled()) {
257             deleteProperties(jsWindowScope, "WebSocket");
258         }
259 
260         jsWindowScope.setPrototypes(prototypes);
261         jsWindowScope.initialize(webWindow, page);
262 
263         applyPolyfills(webClient, browserVersion, context, jsWindowScope);
264     }
265 
266     /**
267      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
268      *
269      * @param jsScope the js scope to set up
270      * @param scopeConfig the {@link ClassConfiguration} that is used for the scope
271      * @param scopeContructorFunctionObject the (already registered) ctor
272      * @param jsConfig the complete jsConfig
273      * @param browserVersion the {@link BrowserVersion}
274      * @param prototypes map of prototypes
275      * @param prototypesPerJSName map of prototypes with the class name as key
276      * @throws Exception in case of error
277      */
278     public static void configureScope(final HtmlUnitScriptable jsScope,
279             final ClassConfiguration scopeConfig,
280             final FunctionObject scopeContructorFunctionObject,
281             final AbstractJavaScriptConfiguration jsConfig,
282             final BrowserVersion browserVersion,
283             final Map<Class<? extends Scriptable>, Scriptable> prototypes,
284             final Map<String, Scriptable> prototypesPerJSName) throws Exception {
285 
286         final Scriptable objectPrototype = ScriptableObject.getObjectPrototype(jsScope);
287 
288         final Map<String, Function> ctorPrototypesPerJSName = new HashMap<>();
289         for (final ClassConfiguration config : jsConfig.getAll()) {
290             final String jsClassName = config.getClassName();
291             Scriptable prototype = prototypesPerJSName.get(jsClassName);
292             final String extendedClassName =
293                     StringUtils.isEmpty(config.getExtendedClassName()) ? null : config.getExtendedClassName();
294 
295             // setup the prototypes
296             if (config == scopeConfig) {
297                 if (extendedClassName == null) {
298                     prototype.setPrototype(objectPrototype);
299                 }
300                 else {
301                     prototype.setPrototype(prototypesPerJSName.get(extendedClassName));
302                 }
303 
304                 // setup constructors
305                 addAsConstructorAndAlias(scopeContructorFunctionObject, jsScope, prototype, config);
306                 configureConstantsStaticPropertiesAndStaticFunctions(config, scopeContructorFunctionObject);
307 
308                 // adjust prototype if needed
309                 if (extendedClassName != null) {
310                     scopeContructorFunctionObject.setPrototype(ctorPrototypesPerJSName.get(extendedClassName));
311                 }
312             }
313             else {
314                 final HtmlUnitScriptable classPrototype = configureClass(config, jsScope);
315                 prototypes.put(config.getHostClass(), classPrototype);
316                 prototypesPerJSName.put(jsClassName, classPrototype);
317                 prototype = classPrototype;
318 
319                 if (extendedClassName == null) {
320                     classPrototype.setPrototype(objectPrototype);
321                 }
322                 else {
323                     classPrototype.setPrototype(prototypesPerJSName.get(extendedClassName));
324                 }
325 
326                 // setup constructors
327                 if (prototype != null) {
328                     final Map.Entry<String, Member> jsConstructor = config.getJsConstructor();
329                     if (jsConstructor == null) {
330                         final ScriptableObject constructor = config.getHostClass().getDeclaredConstructor().newInstance();
331                         ((HtmlUnitScriptable) constructor).setClassName(jsClassName);
332                         defineConstructor(jsScope, prototype, constructor);
333                         configureConstantsStaticPropertiesAndStaticFunctions(config, constructor);
334 
335                         if (config.isJsObject()) {
336                             jsScope.defineProperty(jsClassName, constructor, ScriptableObject.DONTENUM);
337                         }
338                     }
339                     else {
340                         final FunctionObject function = new FunctionObject(jsConstructor.getKey(), jsConstructor.getValue(), jsScope);
341                         ctorPrototypesPerJSName.put(jsClassName, function);
342 
343                         addAsConstructorAndAlias(function, jsScope, prototype, config);
344                         configureConstantsStaticPropertiesAndStaticFunctions(config, function);
345 
346                         if (!config.isJsObject()) {
347                             // addAsConstructorAndAlias(..) calls addAsConstructor() from core-js
348                             // addAsConstructor(..) registeres the ctor in the scope already
349                             // therefore we have to remove here
350                             jsScope.delete(prototype.getClassName());
351                         }
352 
353                         // adjust prototype if needed
354                         if (extendedClassName != null) {
355                             function.setPrototype(ctorPrototypesPerJSName.get(extendedClassName));
356                         }
357                     }
358                 }
359             }
360         }
361     }
362 
363     private static void addAsConstructorAndAlias(final FunctionObject function,
364             final Scriptable scope, final Scriptable prototype, final ClassConfiguration config) {
365         try {
366             function.addAsConstructor(scope, prototype, ScriptableObject.DONTENUM);
367 
368             final String alias = config.getJsConstructorAlias();
369             if (alias != null) {
370                 ScriptableObject.defineProperty(scope, alias, function, ScriptableObject.DONTENUM);
371             }
372         }
373         catch (final Exception e) {
374             // TODO see issue #1897
375             if (LOG.isWarnEnabled()) {
376                 final String newline = System.lineSeparator();
377                 LOG.warn("Error during JavaScriptEngine.init(WebWindow, Context)" + newline
378                         + e.getMessage() + newline
379                         + "prototype: " + prototype.getClassName(), e);
380             }
381         }
382     }
383 
384     private static void additionalCtor(final Window window, final Scriptable proto,
385             final Method ctorMethod, final String prop, final String clazzName) throws Exception {
386         final FunctionObject function = new FunctionObject(prop, ctorMethod, window);
387         final Object prototypeProperty = ScriptableObject.getProperty(window, clazzName);
388         try {
389             function.addAsConstructor(window, proto, ScriptableObject.DONTENUM);
390         }
391         catch (final Exception e) {
392             // TODO see issue #1897
393             if (LOG.isWarnEnabled()) {
394                 final String newline = System.lineSeparator();
395                 LOG.warn("Error during JavaScriptEngine.init(WebWindow, Context)" + newline
396                         + e.getMessage() + newline
397                         + "prototype: " + proto.getClassName(), e);
398             }
399         }
400         ScriptableObject.defineProperty(window, prop, function, ScriptableObject.DONTENUM);
401         ScriptableObject.defineProperty(window, clazzName, prototypeProperty, ScriptableObject.DONTENUM);
402     }
403 
404     /**
405      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
406      *
407      * @param webClient the WebClient
408      * @param browserVersion the BrowserVersion
409      * @param scope the window or the DedicatedWorkerGlobalScope
410      */
411     public static void configureRhino(final WebClient webClient,
412             final BrowserVersion browserVersion, final HtmlUnitScriptable scope) {
413 
414         NativeConsole.init(scope, false, webClient.getWebConsole());
415         final ScriptableObject console = (ScriptableObject) ScriptableObject.getProperty(scope, "console");
416         console.defineFunctionProperties(new String[] {"timeStamp"}, ConsoleCustom.class, ScriptableObject.DONTENUM);
417 
418         // Rhino defines too much methods for us, particularly since implementation of ECMAScript5
419         final ScriptableObject stringPrototype = (ScriptableObject) ScriptableObject.getClassPrototype(scope, "String");
420         deleteProperties(stringPrototype, "equals", "equalsIgnoreCase", "toSource");
421 
422         final ScriptableObject numberPrototype = (ScriptableObject) ScriptableObject.getClassPrototype(scope, "Number");
423         deleteProperties(numberPrototype, "toSource");
424         final ScriptableObject datePrototype = (ScriptableObject) ScriptableObject.getClassPrototype(scope, "Date");
425         deleteProperties(datePrototype, "toSource");
426 
427         deleteProperties(scope, "uneval");
428         removePrototypeProperties(scope, "Object", "toSource");
429         removePrototypeProperties(scope, "Array", "toSource");
430         removePrototypeProperties(scope, "Function", "toSource");
431 
432         deleteProperties(scope, "isXMLName");
433 
434         NativeFunctionToStringFunction.installFix(scope, browserVersion);
435 
436         numberPrototype.defineFunctionProperties(new String[] {"toLocaleString"},
437                 NumberCustom.class, ScriptableObject.DONTENUM);
438 
439         // remove some objects, that Rhino defines in top scope but that we don't want
440         deleteProperties(scope, "Continuation", "StopIteration");
441         if (!browserVersion.hasFeature(JS_ITERATOR_VISIBLE_IN_WINDOW)) {
442             deleteProperties(scope, "Iterator");
443         }
444 
445         final ScriptableObject errorObject = (ScriptableObject) ScriptableObject.getProperty(scope, "Error");
446         if (browserVersion.hasFeature(JS_ERROR_STACK_TRACE_LIMIT)) {
447             errorObject.defineProperty("stackTraceLimit", 10, ScriptableObject.EMPTY);
448         }
449         else {
450             ScriptableObject.deleteProperty(errorObject, "stackTraceLimit");
451         }
452         if (!browserVersion.hasFeature(JS_ERROR_CAPTURE_STACK_TRACE)) {
453             ScriptableObject.deleteProperty(errorObject, "captureStackTrace");
454         }
455 
456         // add Intl
457         final Intl intl = new Intl();
458         intl.setParentScope(scope);
459         scope.defineProperty(intl.getClassName(), intl, ScriptableObject.DONTENUM);
460         intl.defineProperties(browserVersion);
461     }
462 
463     /**
464      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
465      *
466      * @param webClient the WebClient
467      * @param browserVersion the BrowserVersion
468      * @param context the current context
469      * @param scriptable the window or the DedicatedWorkerGlobalScope
470      * @throws IOException in case of problems
471      */
472     public static void applyPolyfills(final WebClient webClient, final BrowserVersion browserVersion,
473             final Context context, final HtmlUnitScriptable scriptable) throws IOException {
474 
475         if (webClient.getOptions().isFetchPolyfillEnabled()) {
476             Polyfill.getFetchPolyfill().apply(context, scriptable);
477         }
478     }
479 
480     private static void defineConstructor(final HtmlUnitScriptable window,
481             final Scriptable prototype, final ScriptableObject constructor) {
482         constructor.setParentScope(window);
483         try {
484             ScriptableObject.defineProperty(prototype, "constructor", constructor,
485                     ScriptableObject.DONTENUM  | ScriptableObject.PERMANENT | ScriptableObject.READONLY);
486         }
487         catch (final Exception e) {
488             // TODO see issue #1897
489             if (LOG.isWarnEnabled()) {
490                 final String newline = System.lineSeparator();
491                 LOG.warn("Error during JavaScriptEngine.init(WebWindow, Context)" + newline
492                         + e.getMessage() + newline
493                         + "prototype: " + prototype.getClassName(), e);
494             }
495         }
496 
497         try {
498             ScriptableObject.defineProperty(constructor, "prototype", prototype,
499                     ScriptableObject.DONTENUM  | ScriptableObject.PERMANENT | ScriptableObject.READONLY);
500         }
501         catch (final Exception e) {
502             // TODO see issue #1897
503             if (LOG.isWarnEnabled()) {
504                 final String newline = System.lineSeparator();
505                 LOG.warn("Error during JavaScriptEngine.init(WebWindow, Context)" + newline
506                         + e.getMessage() + newline
507                         + "prototype: " + prototype.getClassName(), e);
508             }
509         }
510     }
511 
512     /**
513      * Deletes the properties with the provided names.
514      * @param scope the scope from which properties have to be removed
515      * @param propertiesToDelete the list of property names
516      */
517     private static void deleteProperties(final Scriptable scope, final String... propertiesToDelete) {
518         for (final String property : propertiesToDelete) {
519             scope.delete(property);
520         }
521     }
522 
523     /**
524      * Removes prototype properties.
525      * @param scope the scope
526      * @param className the class for which properties should be removed
527      * @param properties the properties to remove
528      */
529     private static void removePrototypeProperties(final Scriptable scope, final String className,
530             final String... properties) {
531         final ScriptableObject prototype = (ScriptableObject) ScriptableObject.getClassPrototype(scope, className);
532         for (final String property : properties) {
533             prototype.delete(property);
534         }
535     }
536 
537     /**
538      * Configures the specified class for access via JavaScript.
539      * @param config the configuration settings for the class to be configured
540      * @param window the scope within which to configure the class
541      * @throws InstantiationException if the new class cannot be instantiated
542      * @throws IllegalAccessException if we don't have access to create the new instance
543      * @return the created prototype
544      * @throws Exception in case of errors
545      */
546     public static HtmlUnitScriptable configureClass(final ClassConfiguration config, final Scriptable window)
547         throws Exception {
548 
549         final HtmlUnitScriptable prototype = config.getHostClass().getDeclaredConstructor().newInstance();
550         prototype.setParentScope(window);
551         prototype.setClassName(config.getClassName());
552 
553         configureConstantsPropertiesAndFunctions(config, prototype);
554 
555         return prototype;
556     }
557 
558     /**
559      * Configures constants, static properties and static functions on the object.
560      * @param config the configuration for the object
561      * @param scriptable the object to configure
562      */
563     private static void configureConstantsStaticPropertiesAndStaticFunctions(final ClassConfiguration config,
564             final ScriptableObject scriptable) {
565         configureConstants(config, scriptable);
566         configureStaticProperties(config, scriptable);
567         configureStaticFunctions(config, scriptable);
568     }
569 
570     /**
571      * Configures constants, properties and functions on the object.
572      * @param config the configuration for the object
573      * @param scriptable the object to configure
574      */
575     private static void configureConstantsPropertiesAndFunctions(final ClassConfiguration config,
576             final ScriptableObject scriptable) {
577         configureConstants(config, scriptable);
578         configureProperties(config, scriptable);
579         configureFunctions(config, scriptable);
580         configureSymbolConstants(config, scriptable);
581         configureSymbols(config, scriptable);
582     }
583 
584     private static void configureFunctions(final ClassConfiguration config, final ScriptableObject scriptable) {
585         // the functions
586         final Map<String, Method> functionMap = config.getFunctionMap();
587         if (functionMap != null) {
588             for (final Entry<String, Method> functionInfo : functionMap.entrySet()) {
589                 final String functionName = functionInfo.getKey();
590                 final Method method = functionInfo.getValue();
591                 final FunctionObject functionObject = new FunctionObject(functionName, method, scriptable);
592                 scriptable.defineProperty(functionName, functionObject, ScriptableObject.EMPTY);
593             }
594         }
595     }
596 
597     private static void configureConstants(final ClassConfiguration config, final ScriptableObject scriptable) {
598         final List<ConstantInfo> constants = config.getConstants();
599         if (constants != null) {
600             for (final ConstantInfo constantInfo : constants) {
601                 scriptable.defineProperty(constantInfo.getName(), constantInfo.getValue(), constantInfo.getFlag());
602             }
603         }
604     }
605 
606     private static void configureProperties(final ClassConfiguration config, final ScriptableObject scriptable) {
607         final Map<String, PropertyInfo> propertyMap = config.getPropertyMap();
608         if (propertyMap != null) {
609             for (final Entry<String, PropertyInfo> propertyEntry : propertyMap.entrySet()) {
610                 final PropertyInfo info = propertyEntry.getValue();
611                 final Method readMethod = info.getReadMethod();
612                 final Method writeMethod = info.getWriteMethod();
613                 scriptable.defineProperty(propertyEntry.getKey(), null, readMethod, writeMethod, ScriptableObject.EMPTY);
614             }
615         }
616     }
617 
618     private static void configureStaticProperties(final ClassConfiguration config, final ScriptableObject scriptable) {
619         final Map<String, PropertyInfo> staticPropertyMap = config.getStaticPropertyMap();
620         if (staticPropertyMap != null) {
621             for (final Entry<String, ClassConfiguration.PropertyInfo> propertyEntry : staticPropertyMap.entrySet()) {
622                 final String propertyName = propertyEntry.getKey();
623                 final Method readMethod = propertyEntry.getValue().getReadMethod();
624                 final Method writeMethod = propertyEntry.getValue().getWriteMethod();
625                 final int flag = ScriptableObject.EMPTY;
626 
627                 scriptable.defineProperty(propertyName, null, readMethod, writeMethod, flag);
628             }
629         }
630     }
631 
632     private static void configureStaticFunctions(final ClassConfiguration config,
633             final ScriptableObject scriptable) {
634         final Map<String, Method> staticFunctionMap = config.getStaticFunctionMap();
635         if (staticFunctionMap != null) {
636             for (final Entry<String, Method> staticFunctionInfo : staticFunctionMap.entrySet()) {
637                 final String functionName = staticFunctionInfo.getKey();
638                 final Method method = staticFunctionInfo.getValue();
639                 final FunctionObject staticFunctionObject = new FunctionObject(functionName, method,
640                         scriptable);
641                 scriptable.defineProperty(functionName, staticFunctionObject, ScriptableObject.EMPTY);
642             }
643         }
644     }
645 
646     private static void configureSymbolConstants(final ClassConfiguration config, final ScriptableObject scriptable) {
647         final Map<Symbol, String> symbolConstantMap = config.getSymbolConstantMap();
648         if (symbolConstantMap != null) {
649             for (final Entry<Symbol, String> symbolInfo : symbolConstantMap.entrySet()) {
650                 scriptable.defineProperty(symbolInfo.getKey(), symbolInfo.getValue(), ScriptableObject.DONTENUM | ScriptableObject.READONLY);
651             }
652         }
653     }
654 
655     private static void configureSymbols(final ClassConfiguration config,
656             final ScriptableObject scriptable) {
657         final Map<Symbol, Method> symbolMap = config.getSymbolMap();
658         if (symbolMap != null) {
659             for (final Entry<Symbol, Method> symbolInfo : symbolMap.entrySet()) {
660                 final Symbol symbol = symbolInfo.getKey();
661                 final Method method = symbolInfo.getValue();
662                 final String methodName = method.getName();
663 
664                 final Callable symbolFunction = scriptable.has(methodName, scriptable)
665                         ? (Callable) scriptable.get(methodName, scriptable)
666                         : new FunctionObject(methodName, method, scriptable);
667                 scriptable.defineProperty(symbol, symbolFunction, ScriptableObject.DONTENUM);
668             }
669         }
670     }
671 
672     /**
673      * Register WebWindow with the JavaScriptExecutor.
674      * @param webWindow the WebWindow to be registered.
675      */
676     @Override
677     public synchronized void registerWindowAndMaybeStartEventLoop(final WebWindow webWindow) {
678         if (shutdownPending_) {
679             return;
680         }
681 
682         final WebClient webClient = getWebClient();
683         if (webClient != null) {
684             if (javaScriptExecutor_ == null) {
685                 javaScriptExecutor_ = BackgroundJavaScriptFactory.theFactory().createJavaScriptExecutor(webClient);
686             }
687             javaScriptExecutor_.addWindow(webWindow);
688         }
689     }
690 
691     /**
692      * {@inheritDoc}
693      */
694     @Override
695     public void prepareShutdown() {
696         shutdownPending_ = true;
697     }
698 
699     /**
700      * Shutdown the JavaScriptEngine.
701      */
702     @Override
703     public void shutdown() {
704         webClient_ = null;
705         contextFactory_ = null;
706         jsConfig_ = null;
707 
708         if (javaScriptExecutor_ != null) {
709             javaScriptExecutor_.shutdown();
710             javaScriptExecutor_ = null;
711         }
712         if (postponedActions_ != null) {
713             postponedActions_.remove();
714         }
715         if (javaScriptRunning_ != null) {
716             javaScriptRunning_.remove();
717         }
718         holdPostponedActions_ = false;
719     }
720 
721     /**
722      * {@inheritDoc}
723      */
724     @Override
725     public Script compile(final HtmlPage owningPage, final Scriptable scope, final String sourceCode,
726             final String sourceName, final int startLine) {
727         WebAssert.notNull("sourceCode", sourceCode);
728 
729         if (LOG.isTraceEnabled()) {
730             final String newline = System.lineSeparator();
731             LOG.trace("Javascript compile " + sourceName + newline + sourceCode + newline);
732         }
733 
734         final HtmlUnitCompileContextAction action = new HtmlUnitCompileContextAction(owningPage, sourceCode, sourceName, startLine);
735         return (Script) getContextFactory().callSecured(action, owningPage);
736     }
737 
738     /**
739      * Forwards this to the {@link HtmlUnitContextFactory} but with checking shutdown handling.
740      *
741      * @param <T> return type of the action
742      * @param action the contextAction
743      * @param page the page
744      * @return the result of the call
745      */
746     public final <T> T callSecured(final ContextAction<T> action, final HtmlPage page) {
747         if (shutdownPending_ || webClient_ == null) {
748             // shutdown was already called
749             return null;
750         }
751 
752         return getContextFactory().callSecured(action, page);
753     }
754 
755     /**
756      * {@inheritDoc}
757      */
758     @Override
759     public Object execute(final HtmlPage page,
760                            final Scriptable scope,
761                            final String sourceCode,
762                            final String sourceName,
763                            final int startLine) {
764         final Script script = compile(page, scope, sourceCode, sourceName, startLine);
765         if (script == null) {
766             // happens with syntax error + throwExceptionOnScriptError = false
767             return null;
768         }
769         return execute(page, scope, script);
770     }
771 
772     /**
773      * {@inheritDoc}
774      */
775     @Override
776     public Object execute(final HtmlPage page, final Scriptable scope, final Script script) {
777         if (shutdownPending_ || webClient_ == null) {
778             // shutdown was already called
779             return null;
780         }
781 
782         final HtmlUnitContextAction action = new HtmlUnitContextAction(page) {
783             @Override
784             public Object doRun(final Context cx) {
785                 return script.exec(cx, scope);
786             }
787 
788             @Override
789             protected String getSourceCode(final Context cx) {
790                 return null;
791             }
792         };
793 
794         return getContextFactory().callSecured(action, page);
795     }
796 
797     /**
798      * Calls a JavaScript function and return the result.
799      * @param page the page
800      * @param javaScriptFunction the function to call
801      * @param thisObject the this object for class method calls
802      * @param args the list of arguments to pass to the function
803      * @param node the HTML element that will act as the context
804      * @return the result of the function call
805      */
806     public Object callFunction(
807             final HtmlPage page,
808             final Function javaScriptFunction,
809             final Scriptable thisObject,
810             final Object[] args,
811             final DomNode node) {
812 
813         final Scriptable scope = getScope(page, node);
814 
815         return callFunction(page, javaScriptFunction, scope, thisObject, args);
816     }
817 
818     /**
819      * Calls the given function taking care of synchronization issues.
820      * @param page the interactive page that caused this script to executed
821      * @param function the JavaScript function to execute
822      * @param scope the execution scope
823      * @param thisObject the 'this' object
824      * @param args the function's arguments
825      * @return the function result
826      */
827     public Object callFunction(final HtmlPage page, final Function function,
828             final Scriptable scope, final Scriptable thisObject, final Object[] args) {
829         if (shutdownPending_ || webClient_ == null) {
830             // shutdown was already called
831             return null;
832         }
833 
834         final HtmlUnitContextAction action = new HtmlUnitContextAction(page) {
835             @Override
836             public Object doRun(final Context cx) {
837                 if (ScriptRuntime.hasTopCall(cx)) {
838                     return function.call(cx, scope, thisObject, args);
839                 }
840                 return ScriptRuntime.doTopCall(function, cx, scope, thisObject, args, cx.isStrictMode());
841             }
842             @Override
843             protected String getSourceCode(final Context cx) {
844                 return cx.decompileFunction(function, 2);
845             }
846         };
847         return getContextFactory().callSecured(action, page);
848     }
849 
850     private static Scriptable getScope(final HtmlPage page, final DomNode node) {
851         if (node != null) {
852             return node.getScriptableObject();
853         }
854         return page.getEnclosingWindow().getScriptableObject();
855     }
856 
857     /**
858      * Indicates if JavaScript is running in current thread.
859      * <p>This allows code to know if there own evaluation is has been triggered by some JS code.
860      * @return {@code true} if JavaScript is running
861      */
862     @Override
863     public boolean isScriptRunning() {
864         return Boolean.TRUE.equals(javaScriptRunning_.get());
865     }
866 
867     /**
868      * Special ContextAction only for compiling. This reduces some code and avoid
869      * some calls.
870      */
871     private final class HtmlUnitCompileContextAction implements ContextAction<Object> {
872         private final HtmlPage page_;
873         private final String sourceCode_;
874         private final String sourceName_;
875         private final int startLine_;
876 
877         HtmlUnitCompileContextAction(final HtmlPage page, final String sourceCode, final String sourceName, final int startLine) {
878             page_ = page;
879             sourceCode_ = sourceCode;
880             sourceName_ = sourceName;
881             startLine_ = startLine;
882         }
883 
884         @Override
885         public Object run(final Context cx) {
886             try {
887                 final Object response;
888                 cx.putThreadLocal(KEY_STARTING_PAGE, page_);
889                 synchronized (page_) { // 2 scripts can't be executed in parallel for one page
890                     if (page_ != page_.getEnclosingWindow().getEnclosedPage()) {
891                         return null; // page has been unloaded
892                     }
893                     response = cx.compileString(sourceCode_, sourceName_, startLine_, null);
894 
895                 }
896 
897                 return response;
898             }
899             catch (final Exception e) {
900                 handleJavaScriptException(new ScriptException(page_, e, sourceCode_), true);
901                 return null;
902             }
903             catch (final TimeoutError e) {
904                 handleJavaScriptTimeoutError(page_, e);
905                 return null;
906             }
907         }
908     }
909 
910     /**
911      * Facility for ContextAction usage.
912      * ContextAction should be preferred because according to Rhino doc it
913      * "guarantees proper association of Context instances with the current thread and is faster".
914      */
915     private abstract class HtmlUnitContextAction implements ContextAction<Object> {
916         private final HtmlPage page_;
917 
918         HtmlUnitContextAction(final HtmlPage page) {
919             page_ = page;
920         }
921 
922         @Override
923         public final Object run(final Context cx) {
924             final Boolean javaScriptAlreadyRunning = javaScriptRunning_.get();
925             javaScriptRunning_.set(Boolean.TRUE);
926 
927             try {
928                 final Object response;
929                 synchronized (page_) { // 2 scripts can't be executed in parallel for one page
930                     if (page_ != page_.getEnclosingWindow().getEnclosedPage()) {
931                         return null; // page has been unloaded
932                     }
933                     response = doRun(cx);
934                 }
935 
936                 cx.processMicrotasks();
937 
938                 // doProcessPostponedActions is synchronized
939                 // moved out of the sync block to avoid deadlocks
940                 if (!holdPostponedActions_) {
941                     doProcessPostponedActions();
942                 }
943 
944                 return response;
945             }
946             catch (final Exception e) {
947                 handleJavaScriptException(new ScriptException(page_, e, getSourceCode(cx)), true);
948                 return null;
949             }
950             catch (final TimeoutError e) {
951                 handleJavaScriptTimeoutError(page_, e);
952                 return null;
953             }
954             finally {
955                 javaScriptRunning_.set(javaScriptAlreadyRunning);
956             }
957         }
958 
959         protected abstract Object doRun(Context cx);
960 
961         protected abstract String getSourceCode(Context cx);
962     }
963 
964     private void doProcessPostponedActions() {
965         holdPostponedActions_ = false;
966 
967         final WebClient webClient = getWebClient();
968         if (webClient == null) {
969             // shutdown was already called
970             postponedActions_.set(null);
971             return;
972         }
973 
974         try {
975             webClient.loadDownloadedResponses();
976         }
977         catch (final RuntimeException e) {
978             throw e;
979         }
980         catch (final Exception e) {
981             throw new RuntimeException(e);
982         }
983 
984         final List<PostponedAction> actions = postponedActions_.get();
985         if (actions != null && !actions.isEmpty()) {
986             postponedActions_.set(new ArrayList<>());
987             try {
988                 for (final PostponedAction action : actions) {
989                     if (LOG.isDebugEnabled()) {
990                         LOG.debug("Processing PostponedAction " + action);
991                     }
992 
993                     // verify that the page that registered this PostponedAction is still alive
994                     if (action.isStillAlive()) {
995                         action.execute();
996                     }
997                 }
998             }
999             catch (final RuntimeException e) {
1000                 throw e;
1001             }
1002             catch (final Exception e) {
1003                 throw JavaScriptEngine.throwAsScriptRuntimeEx(e);
1004             }
1005         }
1006     }
1007 
1008     /**
1009      * Adds an action that should be executed first when the script currently being executed has finished.
1010      * @param action the action
1011      */
1012     @Override
1013     public void addPostponedAction(final PostponedAction action) {
1014         if (shutdownPending_) {
1015             return;
1016         }
1017 
1018         List<PostponedAction> actions = postponedActions_.get();
1019         if (actions == null) {
1020             actions = new ArrayList<>();
1021             postponedActions_.set(actions);
1022         }
1023         actions.add(action);
1024     }
1025 
1026     /**
1027      * Handles an exception that occurred during execution of JavaScript code.
1028      * @param scriptException the exception
1029      * @param triggerOnError if true, this triggers the onerror handler
1030      */
1031     protected void handleJavaScriptException(final ScriptException scriptException, final boolean triggerOnError) {
1032         final WebClient webClient = getWebClient();
1033         if (shutdownPending_ || webClient == null) {
1034             // shutdown was already called
1035             return;
1036         }
1037 
1038         // Trigger window.onerror, if it has been set.
1039         final HtmlPage page = scriptException.getPage();
1040         if (triggerOnError && page != null) {
1041             final WebWindow window = page.getEnclosingWindow();
1042             if (window != null) {
1043                 final Window w = window.getScriptableObject();
1044                 if (w != null) {
1045                     try {
1046                         w.triggerOnError(scriptException);
1047                     }
1048                     catch (final Exception e) {
1049                         handleJavaScriptException(new ScriptException(page, e, null), false);
1050                     }
1051                 }
1052             }
1053         }
1054 
1055         webClient.getJavaScriptErrorListener().scriptException(page, scriptException);
1056         // Throw a Java exception if the user wants us to.
1057         if (webClient.getOptions().isThrowExceptionOnScriptError()) {
1058             throw scriptException;
1059         }
1060     }
1061 
1062     /**
1063      * Handles an exception that occurred during execution of JavaScript code.
1064      * @param page the page in which the script causing this exception was executed
1065      * @param e the timeout error that was thrown from the script engine
1066      */
1067     protected void handleJavaScriptTimeoutError(final HtmlPage page, final TimeoutError e) {
1068         final WebClient webClient = getWebClient();
1069         if (shutdownPending_ || webClient == null) {
1070             // shutdown was already called
1071             return;
1072         }
1073 
1074         webClient.getJavaScriptErrorListener().timeoutError(page, e.getAllowedTime(), e.getExecutionTime());
1075         if (webClient.getOptions().isThrowExceptionOnScriptError()) {
1076             throw new RuntimeException(e);
1077         }
1078         LOG.info("Caught script timeout error", e);
1079     }
1080 
1081     /**
1082      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
1083      * Indicates that no postponed action should be executed.
1084      */
1085     @Override
1086     public void holdPosponedActions() {
1087         holdPostponedActions_ = true;
1088     }
1089 
1090     /**
1091      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
1092      * Process postponed actions, if any.
1093      */
1094     @Override
1095     public void processPostponedActions() {
1096         doProcessPostponedActions();
1097     }
1098 
1099     /**
1100      * Re-initializes transient fields when an object of this type is deserialized.
1101      */
1102     private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
1103         in.defaultReadObject();
1104         initTransientFields();
1105     }
1106 
1107     private void initTransientFields() {
1108         javaScriptRunning_ = new ThreadLocal<>();
1109         postponedActions_ = new ThreadLocal<>();
1110         holdPostponedActions_ = false;
1111         shutdownPending_ = false;
1112     }
1113 
1114     /**
1115      * Gets the class of the JavaScript object for the node class.
1116      * @param c the node class {@link DomNode} or some subclass.
1117      * @return {@code null} if none found
1118      */
1119     public Class<? extends HtmlUnitScriptable> getJavaScriptClass(final Class<?> c) {
1120         return jsConfig_.getDomJavaScriptMappingFor(c);
1121     }
1122 
1123     /**
1124      * Gets the associated configuration.
1125      * @return the configuration
1126      */
1127     @Override
1128     public JavaScriptConfiguration getJavaScriptConfiguration() {
1129         return jsConfig_;
1130     }
1131 
1132     /**
1133      * Returns the javascript timeout.
1134      * @return the javascript timeout
1135      */
1136     @Override
1137     public long getJavaScriptTimeout() {
1138         return getContextFactory().getTimeout();
1139     }
1140 
1141     /**
1142      * Sets the javascript timeout.
1143      * @param timeout the timeout
1144      */
1145     @Override
1146     public void setJavaScriptTimeout(final long timeout) {
1147         getContextFactory().setTimeout(timeout);
1148     }
1149 
1150     /**
1151      * Convert the value to a JavaScript Number value.
1152      *
1153      * @param value a JavaScript value
1154      * @return the corresponding double value converted using the ECMA rules
1155      */
1156     public static double toNumber(final Object value) {
1157         return ScriptRuntime.toNumber(value);
1158     }
1159 
1160     /**
1161      * Convert the value to a JavaScript String value.
1162      *
1163      * @param value a JavaScript value
1164      * @return the corresponding String value converted using the ECMA rules
1165      */
1166     public static String toString(final Object value) {
1167         return ScriptRuntime.toString(value);
1168     }
1169 
1170     /**
1171      * Convert the value to a JavaScript boolean value.
1172      *
1173      * @param value a JavaScript value
1174      * @return the corresponding boolean value converted using the ECMA rules
1175      */
1176     public static boolean toBoolean(final Object value) {
1177         return ScriptRuntime.toBoolean(value);
1178     }
1179 
1180     /**
1181      * Rethrow the exception wrapping it as the script runtime exception.
1182      *
1183      * @param e the exception to rethrow
1184      * @return RuntimeException as dummy the method always throws
1185      */
1186     public static RuntimeException throwAsScriptRuntimeEx(final Throwable e) {
1187         throw Context.throwAsScriptRuntimeEx(e);
1188     }
1189 
1190     /**
1191      * Report a runtime error using the error reporter for the current thread.
1192      *
1193      * @param message the error message to report
1194      * @return RuntimeException as dummy the method always throws
1195      */
1196     public static RuntimeException reportRuntimeError(final String message) {
1197         throw Context.reportRuntimeError(message);
1198     }
1199 
1200     /**
1201      * Report a runtime error using the error reporter for the current thread.
1202      *
1203      * @param message the error message to report
1204      * @return EcmaError
1205      */
1206     public static EcmaError syntaxError(final String message) {
1207         return ScriptRuntime.syntaxError(message);
1208     }
1209 
1210     /**
1211      * Report a runtime error using the error reporter for the current thread.
1212      *
1213      * @param message the error message to report
1214      * @return EcmaError
1215      */
1216     public static EcmaError typeError(final String message) {
1217         return ScriptRuntime.typeError(message);
1218     }
1219 
1220     /**
1221      * Report a TypeError with the message "Illegal constructor.".
1222      *
1223      * @return EcmaError
1224      */
1225     public static EcmaError typeErrorIllegalConstructor() {
1226         throw JavaScriptEngine.typeError("Illegal constructor.");
1227     }
1228 
1229     /**
1230      * Report a runtime error using the error reporter for the current thread.
1231      *
1232      * @param message the error message to report
1233      * @return EcmaError
1234      */
1235     public static EcmaError rangeError(final String message) {
1236         return ScriptRuntime.rangeError(message);
1237     }
1238 
1239     /**
1240      * @param error the error
1241      * @param message the message
1242      * @return a new EcmaError
1243      */
1244     public static EcmaError constructError(final String error, final String message) {
1245         return ScriptRuntime.constructError(error, message);
1246     }
1247 
1248     /**
1249      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
1250      *
1251      * Creates a {@link DOMException} and encapsulates it into a Rhino-compatible exception.
1252      *
1253      * @param scope the parent scope
1254      * @param message the exception message
1255      * @param type the exception type
1256      * @return the created exception
1257      */
1258     public static RhinoException asJavaScriptException(final HtmlUnitScriptable scope, final String message, final int type) {
1259         final DOMException domException = new DOMException(message, type);
1260         domException.setParentScope(scope);
1261         domException.setPrototype(scope.getPrototype(DOMException.class));
1262 
1263         final EcmaError helper = ScriptRuntime.syntaxError("helper");
1264         String fileName = helper.sourceName();
1265         if (fileName != null) {
1266             fileName = fileName.replaceFirst("script in (.*) from .*", "$1");
1267         }
1268         domException.setLocation(fileName, helper.lineNumber());
1269 
1270         return new JavaScriptException(domException, fileName, helper.lineNumber());
1271     }
1272 
1273     /**
1274      * Create an array with a specified initial length.
1275      *
1276      * @param scope the scope to create the object in
1277      * @param length the initial length (JavaScript arrays may have additional properties added
1278      *     dynamically).
1279      * @return the new array object
1280      */
1281     public static Scriptable newArray(final Scriptable scope, final int length) {
1282         final NativeArray result = new NativeArray(length);
1283         ScriptRuntime.setBuiltinProtoAndParent(result, scope, TopLevel.Builtins.Array);
1284         return result;
1285     }
1286 
1287     /**
1288      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
1289      *
1290      * Create a new ArrayIterator of type NativeArrayIterator.ARRAY_ITERATOR_TYPE.KEYS
1291      *
1292      * @param scope the scope to create the object in
1293      * @param arrayLike the backend
1294      * @return the new NativeArrayIterator
1295      */
1296     public static Scriptable newArrayIteratorTypeKeys(final Scriptable scope, final Scriptable arrayLike) {
1297         return new NativeArrayIterator(scope, arrayLike, NativeArrayIterator.ARRAY_ITERATOR_TYPE.KEYS);
1298     }
1299 
1300     /**
1301      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
1302      *
1303      * Create a new ArrayIterator of type NativeArrayIterator.ARRAY_ITERATOR_TYPE.VALUES
1304      *
1305      * @param scope the scope to create the object in
1306      * @param arrayLike the backend
1307      * @return the new NativeArrayIterator
1308      */
1309     public static Scriptable newArrayIteratorTypeValues(final Scriptable scope, final Scriptable arrayLike) {
1310         return new NativeArrayIterator(scope, arrayLike, NativeArrayIterator.ARRAY_ITERATOR_TYPE.VALUES);
1311     }
1312 
1313     /**
1314      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
1315      *
1316      * Create a new ArrayIterator of type NativeArrayIterator.ARRAY_ITERATOR_TYPE.ENTRIES
1317      *
1318      * @param scope the scope to create the object in
1319      * @param arrayLike the backend
1320      * @return the new NativeArrayIterator
1321      */
1322     public static Scriptable newArrayIteratorTypeEntries(final Scriptable scope, final Scriptable arrayLike) {
1323         return new NativeArrayIterator(scope, arrayLike, NativeArrayIterator.ARRAY_ITERATOR_TYPE.ENTRIES);
1324     }
1325 
1326     /**
1327      * Create an array with a specified initial length.
1328      *
1329      * @param scope the scope to create the object in
1330      * @param elements the initial elements. Each object in this array must be an acceptable
1331      *     JavaScript type and type of array should be exactly Object[], not SomeObjectSubclass[].
1332      * @return the new array object
1333      */
1334     public static Scriptable newArray(final Scriptable scope, final Object[] elements) {
1335         if (elements.getClass().getComponentType() != ScriptRuntime.ObjectClass) {
1336             throw new IllegalArgumentException();
1337         }
1338 
1339         final NativeArray result = new NativeArray(elements);
1340         ScriptRuntime.setBuiltinProtoAndParent(result, scope, TopLevel.Builtins.Array);
1341         return result;
1342     }
1343 
1344     /**
1345      * @param o the object to convert
1346      * @return int value
1347      */
1348     public static int toInt32(final Object o) {
1349         return ScriptRuntime.toInt32(o);
1350     }
1351 
1352     /**
1353      * @param o the object to convert
1354      * @return double value
1355      */
1356     public static double toInteger(final Object o) {
1357         return ScriptRuntime.toInteger(o);
1358     }
1359 
1360     /**
1361      * @param args an array
1362      * @param index the index in the array
1363      * @return double value
1364      */
1365     public static double toInteger(final Object[] args, final int index) {
1366         return ScriptRuntime.toInteger(args, index);
1367     }
1368 
1369     /**
1370      * @param obj the value to check
1371      * @return whether obj is undefined
1372      */
1373     public static boolean isUndefined(final Object obj) {
1374         return org.htmlunit.corejs.javascript.Undefined.isUndefined(obj);
1375     }
1376 
1377     /**
1378      * @param obj the value to check
1379      * @return whether obj is NAN
1380      */
1381     public static boolean isNaN(final Object obj) {
1382         return ScriptRuntime.isNaN(obj);
1383     }
1384 
1385     /**
1386      * @return the top call scope
1387      */
1388     public static Scriptable getTopCallScope() {
1389         return ScriptRuntime.getTopCallScope(Context.getCurrentContext());
1390     }
1391 
1392     /**
1393      * Tries to uncompress the JavaScript code in the provided response.
1394      * @param scriptSource the souce
1395      * @param scriptName the name
1396      * @return the uncompressed JavaScript code
1397      */
1398     public static String uncompressJavaScript(final String scriptSource, final String scriptName) {
1399         final ContextFactory factory = new ContextFactory();
1400         final ContextAction<Object> action = cx -> {
1401             cx.setInterpretedMode(true);
1402             final Script script = cx.compileString(scriptSource, scriptName, 0, null);
1403             return cx.decompileScript(script, 4);
1404         };
1405 
1406         return (String) factory.call(action);
1407     }
1408 
1409     /**
1410      * Evaluates the <code>FindProxyForURL</code> method of the specified content.
1411      * @param browserVersion the browser version to use
1412      * @param content the JavaScript content
1413      * @param url the URL to be retrieved
1414      * @return semicolon-separated result
1415      */
1416     public static String evaluateProxyAutoConfig(final BrowserVersion browserVersion, final String content, final URL url) {
1417         try (Context cx = Context.enter()) {
1418             final ProxyAutoConfigJavaScriptConfiguration jsConfig =
1419                     ProxyAutoConfigJavaScriptConfiguration.getInstance(browserVersion);
1420 
1421             final ScriptableObject scope = cx.initSafeStandardObjects();
1422 
1423             for (final ClassConfiguration config : jsConfig.getAll()) {
1424                 configureFunctions(config, scope);
1425             }
1426 
1427             cx.evaluateString(scope, "var ProxyConfig = function() {}; ProxyConfig.bindings = {}", "<init>", 1, null);
1428             cx.evaluateString(scope, content, "<Proxy Auto-Config>", 1, null);
1429 
1430             final Object[] functionArgs = {url.toExternalForm(), url.getHost()};
1431             final NativeFunction f = (NativeFunction) scope.get("FindProxyForURL", scope);
1432             final Object result = f.call(cx, scope, scope, functionArgs);
1433             return toString(result);
1434         }
1435     }
1436 }