1 // Copyright 2015-present 650 Industries. All rights reserved.
2 package host.exp.exponent.experience
3 
4 import android.app.Activity
5 import android.content.Intent
6 import android.content.pm.PackageManager
7 import android.net.Uri
8 import android.os.Build
9 import android.os.Bundle
10 import android.os.Handler
11 import android.os.Process
12 import android.view.KeyEvent
13 import android.view.View
14 import android.view.ViewGroup
15 import android.widget.FrameLayout
16 import androidx.annotation.UiThread
17 import androidx.appcompat.app.AppCompatActivity
18 import androidx.core.content.ContextCompat
19 import com.facebook.infer.annotation.Assertions
20 import com.facebook.internal.BundleJSONConverter
21 import com.facebook.react.devsupport.DoubleTapReloadRecognizer
22 import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler
23 import com.facebook.react.modules.core.PermissionAwareActivity
24 import com.facebook.react.modules.core.PermissionListener
25 import de.greenrobot.event.EventBus
26 import expo.modules.core.interfaces.Package
27 import expo.modules.updates.manifest.raw.RawManifest
28 import host.exp.exponent.Constants
29 import host.exp.exponent.ExponentManifest
30 import host.exp.exponent.RNObject
31 import host.exp.exponent.analytics.Analytics
32 import host.exp.exponent.analytics.EXL
33 import host.exp.exponent.di.NativeModuleDepsProvider
34 import host.exp.exponent.experience.BaseExperienceActivity.ExperienceContentLoaded
35 import host.exp.exponent.experience.splashscreen.LoadingView
36 import host.exp.exponent.kernel.*
37 import host.exp.exponent.kernel.KernelConstants.AddedExperienceEventEvent
38 import host.exp.exponent.kernel.services.ErrorRecoveryManager
39 import host.exp.exponent.kernel.services.ExpoKernelServiceRegistry
40 import host.exp.exponent.notifications.ExponentNotification
41 import host.exp.exponent.storage.ExponentSharedPreferences
42 import host.exp.exponent.utils.ExperienceActivityUtils
43 import host.exp.exponent.utils.ScopedPermissionsRequester
44 import host.exp.expoview.Exponent
45 import host.exp.expoview.Exponent.InstanceManagerBuilderProperties
46 import host.exp.expoview.Exponent.StartReactInstanceDelegate
47 import host.exp.expoview.R
48 import org.json.JSONException
49 import org.json.JSONObject
50 import versioned.host.exp.exponent.ExponentPackage
51 import java.util.*
52 import javax.inject.Inject
53 
54 abstract class ReactNativeActivity :
55   AppCompatActivity(),
56   DefaultHardwareBackBtnHandler,
57   PermissionAwareActivity {
58 
59   class ExperienceDoneLoadingEvent internal constructor(val activity: Activity)
60 
61   open fun initialProps(expBundle: Bundle?): Bundle? {
62     return expBundle
63   }
64 
65   protected open fun onDoneLoading() {}
66 
67   // Will be called after waitForDrawOverOtherAppPermission
68   protected open fun startReactInstance() {}
69 
70   protected var reactInstanceManager: RNObject =
71     RNObject("com.facebook.react.ReactInstanceManager")
72   protected var isCrashed = false
73 
74   protected var manifestUrl: String? = null
75   var experienceKey: ExperienceKey? = null
76   protected var sdkVersion: String? = null
77   protected var activityId = 0
78 
79   // In detach we want UNVERSIONED most places. We still need the numbered sdk version
80   // when creating cache keys.
81   protected var detachSdkVersion: String? = null
82 
83   protected lateinit var reactRootView: RNObject
84   private lateinit var doubleTapReloadRecognizer: DoubleTapReloadRecognizer
85   var isLoading = true
86     protected set
87   protected var jsBundlePath: String? = null
88   protected var manifest: RawManifest? = null
89   var isInForeground = false
90     protected set
91   private var scopedPermissionsRequester: ScopedPermissionsRequester? = null
92 
93   @Inject
94   protected lateinit var exponentSharedPreferences: ExponentSharedPreferences
95 
96   @Inject
97   lateinit var expoKernelServiceRegistry: ExpoKernelServiceRegistry
98 
99   private lateinit var containerView: FrameLayout
100 
101   /**
102    * This view is optional and available only when the app runs in Expo Go.
103    */
104   private var loadingView: LoadingView? = null
105   private lateinit var reactContainerView: FrameLayout
106   private val handler = Handler()
107 
108   protected open fun shouldCreateLoadingView(): Boolean {
109     return !Constants.isStandaloneApp() || Constants.SHOW_LOADING_VIEW_IN_SHELL_APP
110   }
111 
112   val rootView: View?
113     get() = reactRootView.get() as View?
114 
115   override fun onCreate(savedInstanceState: Bundle?) {
116     super.onCreate(null)
117 
118     containerView = FrameLayout(this)
119     setContentView(containerView)
120 
121     reactContainerView = FrameLayout(this)
122     containerView.addView(reactContainerView)
123 
124     if (shouldCreateLoadingView()) {
125       containerView.setBackgroundColor(
126         ContextCompat.getColor(
127           this,
128           R.color.splashscreen_background
129         )
130       )
131       loadingView = LoadingView(this)
132       loadingView!!.show()
133       containerView.addView(loadingView)
134     }
135 
136     doubleTapReloadRecognizer = DoubleTapReloadRecognizer()
137     Exponent.initialize(this, application)
138     NativeModuleDepsProvider.getInstance().inject(ReactNativeActivity::class.java, this)
139 
140     // Can't call this here because subclasses need to do other initialization
141     // before their listener methods are called.
142     // EventBus.getDefault().registerSticky(this);
143   }
144 
145   protected fun setReactRootView(reactRootView: View) {
146     reactContainerView.removeAllViews()
147     addReactViewToContentContainer(reactRootView)
148   }
149 
150   fun addReactViewToContentContainer(reactView: View) {
151     if (reactView.parent != null) {
152       (reactView.parent as ViewGroup).removeView(reactView)
153     }
154     reactContainerView.addView(reactView)
155   }
156 
157   fun hasReactView(reactView: View): Boolean {
158     return reactView.parent === reactContainerView
159   }
160 
161   protected fun hideLoadingView() {
162     loadingView?.let {
163       val viewGroup = it.parent as ViewGroup?
164       viewGroup?.removeView(it)
165       it.hide()
166     }
167     loadingView = null
168   }
169 
170   protected fun removeAllViewsFromContainer() {
171     containerView.removeAllViews()
172   }
173   // region Loading
174   /**
175    * Successfully finished loading
176    */
177   @UiThread
178   protected fun finishLoading() {
179     waitForReactAndFinishLoading()
180   }
181 
182   /**
183    * There was an error during loading phase
184    */
185   protected fun interruptLoading() {
186     handler.removeCallbacksAndMessages(null)
187   }
188 
189   // Loop until a view is added to the ReactRootView and once it happens run callback
190   private fun waitForReactRootViewToHaveChildrenAndRunCallback(callback: Runnable) {
191     if (reactRootView.isNull) {
192       return
193     }
194 
195     if (reactRootView.call("getChildCount") as Int > 0) {
196       callback.run()
197     } else {
198       handler.postDelayed(
199         { waitForReactRootViewToHaveChildrenAndRunCallback(callback) },
200         VIEW_TEST_INTERVAL_MS
201       )
202     }
203   }
204 
205   /**
206    * Waits for JS side of React to be launched and then performs final launching actions.
207    */
208   private fun waitForReactAndFinishLoading() {
209     if (Constants.isStandaloneApp() && Constants.SHOW_LOADING_VIEW_IN_SHELL_APP) {
210       val layoutParams = containerView.layoutParams
211       layoutParams.height = FrameLayout.LayoutParams.MATCH_PARENT
212       containerView.layoutParams = layoutParams
213     }
214     waitForReactRootViewToHaveChildrenAndRunCallback {
215       onDoneLoading()
216       try {
217         ExperienceActivityUtils.setRootViewBackgroundColor(manifest, rootView)
218       } catch (e: Exception) {
219         EXL.e(TAG, e)
220       }
221       ErrorRecoveryManager.getInstance(experienceKey!!).markExperienceLoaded()
222       pollForEventsToSendToRN()
223       EventBus.getDefault().post(ExperienceDoneLoadingEvent(this))
224       isLoading = false
225     }
226   }
227   // endregion
228   // region SplashScreen
229   /**
230    * Get what version (among versioned classes) of ReactRootView.class SplashScreen module should be looking for.
231    */
232   protected fun getRootViewClass(manifest: RawManifest): Class<out ViewGroup> {
233     val reactRootViewRNClass = reactRootView.rnClass()
234     if (reactRootViewRNClass != null) {
235       return reactRootViewRNClass as Class<out ViewGroup>
236     }
237     var sdkVersion = manifest.getSDKVersionNullable()
238     if (Constants.TEMPORARY_ABI_VERSION != null && Constants.TEMPORARY_ABI_VERSION == this.sdkVersion) {
239       sdkVersion = RNObject.UNVERSIONED
240     }
241     sdkVersion = if (Constants.isStandaloneApp()) RNObject.UNVERSIONED else sdkVersion
242     return RNObject("com.facebook.react.ReactRootView").loadVersion(sdkVersion).rnClass() as Class<out ViewGroup>
243   }
244 
245   // endregion
246   override fun onKeyUp(keyCode: Int, event: KeyEvent): Boolean {
247     if (reactInstanceManager.isNotNull && !isCrashed) {
248       if (devSupportManager.call("getDevSupportEnabled") as Boolean) {
249         val didDoubleTapR = Assertions.assertNotNull(doubleTapReloadRecognizer)
250           .didDoubleTapR(keyCode, currentFocus)
251         if (didDoubleTapR) {
252           devSupportManager.call("reloadExpoApp")
253           return true
254         }
255       }
256     }
257     return super.onKeyUp(keyCode, event)
258   }
259 
260   override fun onBackPressed() {
261     if (reactInstanceManager.isNotNull && !isCrashed) {
262       reactInstanceManager.call("onBackPressed")
263     } else {
264       super.onBackPressed()
265     }
266   }
267 
268   override fun invokeDefaultOnBackPressed() {
269     super.onBackPressed()
270   }
271 
272   override fun onPause() {
273     super.onPause()
274     if (reactInstanceManager.isNotNull && !isCrashed) {
275       reactInstanceManager.onHostPause()
276       // TODO: use onHostPause(activity)
277     }
278   }
279 
280   override fun onResume() {
281     super.onResume()
282     if (reactInstanceManager.isNotNull && !isCrashed) {
283       reactInstanceManager.onHostResume(this, this)
284     }
285   }
286 
287   override fun onDestroy() {
288     super.onDestroy()
289     destroyReactInstanceManager()
290     handler.removeCallbacksAndMessages(null)
291     EventBus.getDefault().unregister(this)
292   }
293 
294   public override fun onNewIntent(intent: Intent) {
295     if (reactInstanceManager.isNotNull && !isCrashed) {
296       try {
297         reactInstanceManager.call("onNewIntent", intent)
298       } catch (e: Throwable) {
299         EXL.e(TAG, e.toString())
300         super.onNewIntent(intent)
301       }
302     } else {
303       super.onNewIntent(intent)
304     }
305   }
306 
307   open val isDebugModeEnabled: Boolean
308     get() = manifest?.isDevelopmentMode() ?: false
309 
310   protected open fun destroyReactInstanceManager() {
311     if (reactInstanceManager.isNotNull && !isCrashed) {
312       reactInstanceManager.call("destroy")
313     }
314   }
315 
316   public override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
317     super.onActivityResult(requestCode, resultCode, data)
318 
319     Exponent.instance.onActivityResult(requestCode, resultCode, data)
320 
321     if (reactInstanceManager.isNotNull && !isCrashed) {
322       reactInstanceManager.call("onActivityResult", this, requestCode, resultCode, data)
323     }
324 
325     // Have permission to draw over other apps. Resume loading.
326     if (requestCode == KernelConstants.OVERLAY_PERMISSION_REQUEST_CODE) {
327       // startReactInstance() checks isInForeground and onActivityResult is called before onResume,
328       // so manually set this here.
329       isInForeground = true
330       startReactInstance()
331     }
332   }
333 
334   fun startReactInstance(
335     delegate: StartReactInstanceDelegate,
336     intentUri: String?,
337     sdkVersion: String?,
338     notification: ExponentNotification?,
339     isShellApp: Boolean,
340     extraNativeModules: List<Any>?,
341     extraExpoPackages: List<Package>?,
342     progressListener: DevBundleDownloadProgressListener
343   ): RNObject {
344     if (isCrashed || !delegate.isInForeground) {
345       // Can sometimes get here after an error has occurred. Return early or else we'll hit
346       // a null pointer at mReactRootView.startReactApplication
347       return RNObject("com.facebook.react.ReactInstanceManager")
348     }
349 
350     val experienceProperties = mapOf<String, Any?>(
351       KernelConstants.MANIFEST_URL_KEY to manifestUrl,
352       KernelConstants.LINKING_URI_KEY to linkingUri,
353       KernelConstants.INTENT_URI_KEY to intentUri,
354       KernelConstants.IS_HEADLESS_KEY to false
355     )
356 
357     val instanceManagerBuilderProperties = InstanceManagerBuilderProperties().apply {
358       this.application = this@ReactNativeActivity.application
359       this.jsBundlePath = this@ReactNativeActivity.jsBundlePath
360       this.experienceProperties = experienceProperties
361       this.expoPackages = extraExpoPackages
362       this.exponentPackageDelegate = delegate.exponentPackageDelegate
363       this.manifest = this@ReactNativeActivity.manifest
364       this.singletonModules = ExponentPackage.getOrCreateSingletonModules(
365         this@ReactNativeActivity.applicationContext,
366         this@ReactNativeActivity.manifest,
367         extraExpoPackages
368       )
369     }
370 
371     val versionedUtils = RNObject("host.exp.exponent.VersionedUtils").loadVersion(sdkVersion)
372     val builder = versionedUtils.callRecursive(
373       "getReactInstanceManagerBuilder",
374       instanceManagerBuilderProperties
375     )
376 
377     builder.call("setCurrentActivity", this)
378 
379     // ReactNativeInstance is considered to be resumed when it has its activity attached, which is expected to be the case here
380     builder.call(
381       "setInitialLifecycleState",
382       RNObject.versionedEnum(sdkVersion, "com.facebook.react.common.LifecycleState", "RESUMED")
383     )
384 
385     if (extraNativeModules != null) {
386       for (nativeModule in extraNativeModules) {
387         builder.call("addPackage", nativeModule)
388       }
389     }
390 
391     if (delegate.isDebugModeEnabled) {
392       val debuggerHost = manifest!!.getDebuggerHost()
393       val mainModuleName = manifest!!.getMainModuleName()
394       Exponent.enableDeveloperSupport(debuggerHost, mainModuleName, builder)
395 
396       val devLoadingView =
397         RNObject("com.facebook.react.devsupport.DevLoadingViewController").loadVersion(sdkVersion)
398       devLoadingView.callRecursive("setDevLoadingEnabled", false)
399 
400       val devBundleDownloadListener =
401         RNObject("host.exp.exponent.ExponentDevBundleDownloadListener")
402           .loadVersion(sdkVersion)
403           .construct(progressListener)
404       builder.callRecursive("setDevBundleDownloadListener", devBundleDownloadListener.get())
405     } else {
406       waitForReactAndFinishLoading()
407     }
408 
409     val bundle = Bundle()
410     val exponentProps = JSONObject()
411     if (notification != null) {
412       bundle.putString("notification", notification.body) // Deprecated
413       try {
414         exponentProps.put("notification", notification.toJSONObject("selected"))
415       } catch (e: JSONException) {
416         e.printStackTrace()
417       }
418     }
419 
420     try {
421       exponentProps.put("manifestString", manifest.toString())
422       exponentProps.put("shell", isShellApp)
423       exponentProps.put("initialUri", intentUri)
424     } catch (e: JSONException) {
425       EXL.e(TAG, e)
426     }
427 
428     val metadata = exponentSharedPreferences.getExperienceMetadata(experienceKey)
429     if (metadata != null) {
430       // TODO: fix this. this is the only place that EXPERIENCE_METADATA_UNREAD_REMOTE_NOTIFICATIONS is sent to the experience,
431       // we need to send them with the standard notification events so that you can get all the unread notification through an event
432       // Copy unreadNotifications into exponentProps
433       if (metadata.has(ExponentSharedPreferences.EXPERIENCE_METADATA_UNREAD_REMOTE_NOTIFICATIONS)) {
434         try {
435           val unreadNotifications =
436             metadata.getJSONArray(ExponentSharedPreferences.EXPERIENCE_METADATA_UNREAD_REMOTE_NOTIFICATIONS)
437           delegate.handleUnreadNotifications(unreadNotifications)
438         } catch (e: JSONException) {
439           e.printStackTrace()
440         }
441         metadata.remove(ExponentSharedPreferences.EXPERIENCE_METADATA_UNREAD_REMOTE_NOTIFICATIONS)
442       }
443       exponentSharedPreferences.updateExperienceMetadata(experienceKey, metadata)
444     }
445 
446     try {
447       bundle.putBundle("exp", BundleJSONConverter.convertToBundle(exponentProps))
448     } catch (e: JSONException) {
449       throw Error("JSONObject failed to be converted to Bundle", e)
450     }
451 
452     if (!delegate.isInForeground) {
453       return RNObject("com.facebook.react.ReactInstanceManager")
454     }
455 
456     Analytics.markEvent(Analytics.TimedEvent.STARTED_LOADING_REACT_NATIVE)
457     val mReactInstanceManager = builder.callRecursive("build")
458     val devSettings =
459       mReactInstanceManager.callRecursive("getDevSupportManager").callRecursive("getDevSettings")
460     if (devSettings != null) {
461       devSettings.setField("exponentActivityId", activityId)
462       if (devSettings.call("isRemoteJSDebugEnabled") as Boolean) {
463         waitForReactAndFinishLoading()
464       }
465     }
466 
467     mReactInstanceManager.onHostResume(this, this)
468     val appKey = manifest!!.getAppKey()
469     reactRootView.call(
470       "startReactApplication",
471       mReactInstanceManager.get(),
472       appKey ?: KernelConstants.DEFAULT_APPLICATION_KEY,
473       initialProps(bundle)
474     )
475 
476     // Requesting layout to make sure {@link ReactRootView} attached to {@link ReactInstanceManager}
477     // Otherwise, {@link ReactRootView} will hang in {@link waitForReactRootViewToHaveChildrenAndRunCallback}.
478     // Originally react-native will automatically attach after `startReactApplication`.
479     // After https://github.com/facebook/react-native/commit/2c896d35782cd04c8,
480     // the only remaining path is by `onMeasure`.
481     reactRootView.call("requestLayout")
482 
483     return mReactInstanceManager
484   }
485 
486   protected fun shouldShowErrorScreen(errorMessage: ExponentErrorMessage): Boolean {
487     if (isLoading) {
488       // Don't hit ErrorRecoveryManager until bridge is initialized.
489       // This is the same on iOS.
490       return true
491     }
492     val errorRecoveryManager = ErrorRecoveryManager.getInstance(experienceKey!!)
493     errorRecoveryManager.markErrored()
494 
495     if (!errorRecoveryManager.shouldReloadOnError()) {
496       return true
497     }
498 
499     if (!KernelProvider.instance.reloadVisibleExperience(manifestUrl!!)) {
500       // Kernel couldn't reload, show error screen
501       return true
502     }
503 
504     errorQueue.clear()
505     try {
506       val eventProperties = JSONObject().apply {
507         put(Analytics.USER_ERROR_MESSAGE, errorMessage.userErrorMessage())
508         put(Analytics.DEVELOPER_ERROR_MESSAGE, errorMessage.developerErrorMessage())
509         put(Analytics.MANIFEST_URL, manifestUrl)
510       }
511       Analytics.logEvent(Analytics.ERROR_RELOADED, eventProperties)
512     } catch (e: Exception) {
513       EXL.e(TAG, e.message)
514     }
515 
516     return false
517   }
518 
519   fun onEventMainThread(event: AddedExperienceEventEvent) {
520     if (manifestUrl != null && manifestUrl == event.manifestUrl) {
521       pollForEventsToSendToRN()
522     }
523   }
524 
525   fun onEvent(event: ExperienceContentLoaded?) {}
526 
527   private fun pollForEventsToSendToRN() {
528     if (manifestUrl == null) {
529       return
530     }
531 
532     try {
533       val rctDeviceEventEmitter =
534         RNObject("com.facebook.react.modules.core.DeviceEventManagerModule\$RCTDeviceEventEmitter")
535       rctDeviceEventEmitter.loadVersion(detachSdkVersion)
536       val existingEmitter = reactInstanceManager.callRecursive("getCurrentReactContext")
537         .callRecursive("getJSModule", rctDeviceEventEmitter.rnClass())
538       if (existingEmitter != null) {
539         val events = KernelProvider.instance.consumeExperienceEvents(manifestUrl!!)
540         for ((eventName, eventPayload) in events) {
541           existingEmitter.call("emit", eventName, eventPayload)
542         }
543       }
544     } catch (e: Throwable) {
545       EXL.e(TAG, e)
546     }
547   }
548 
549   // for getting global permission
550   override fun checkSelfPermission(permission: String): Int {
551     return super.checkPermission(permission, Process.myPid(), Process.myUid())
552   }
553 
554   override fun shouldShowRequestPermissionRationale(permission: String): Boolean {
555     // in scoped application we don't have `don't ask again` button
556     return if (!Constants.isStandaloneApp() && checkSelfPermission(permission) == PackageManager.PERMISSION_GRANTED) {
557       true
558     } else super.shouldShowRequestPermissionRationale(permission)
559   }
560 
561   override fun requestPermissions(
562     permissions: Array<String>,
563     requestCode: Int,
564     listener: PermissionListener
565   ) {
566     if (requestCode == ScopedPermissionsRequester.EXPONENT_PERMISSIONS_REQUEST) {
567       val name = manifest!!.getName()
568       scopedPermissionsRequester = ScopedPermissionsRequester(experienceKey)
569       scopedPermissionsRequester!!.requestPermissions(this, name ?: "", permissions, listener)
570     } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
571       super.requestPermissions(permissions, requestCode)
572     }
573   }
574 
575   override fun onRequestPermissionsResult(
576     requestCode: Int,
577     permissions: Array<String>,
578     grantResults: IntArray
579   ) {
580     if (requestCode == ScopedPermissionsRequester.EXPONENT_PERMISSIONS_REQUEST) {
581       if (permissions.isNotEmpty() && grantResults.size == permissions.size && scopedPermissionsRequester != null) {
582         if (scopedPermissionsRequester!!.onRequestPermissionsResult(permissions, grantResults)) {
583           scopedPermissionsRequester = null
584         }
585       }
586     } else {
587       super.onRequestPermissionsResult(requestCode, permissions, grantResults)
588     }
589   }
590 
591   // for getting scoped permission
592   override fun checkPermission(permission: String, pid: Int, uid: Int): Int {
593     val globalResult = super.checkPermission(permission, pid, uid)
594     return expoKernelServiceRegistry.permissionsKernelService.getPermissions(
595       globalResult,
596       packageManager,
597       permission,
598       experienceKey!!
599     )
600   }
601 
602   val devSupportManager: RNObject
603     get() = reactInstanceManager.callRecursive("getDevSupportManager")
604 
605   // deprecated in favor of Expo.Linking.makeUrl
606   // TODO: remove this
607   private val linkingUri: String?
608     get() = if (Constants.SHELL_APP_SCHEME != null) {
609       Constants.SHELL_APP_SCHEME + "://"
610     } else {
611       val uri = Uri.parse(manifestUrl)
612       val host = uri.host
613       if (host != null && (
614         host == "exp.host" || host == "expo.io" || host == "exp.direct" || host == "expo.test" ||
615           host.endsWith(".exp.host") || host.endsWith(".expo.io") || host.endsWith(".exp.direct") || host.endsWith(
616             ".expo.test"
617           )
618         )
619       ) {
620         val pathSegments = uri.pathSegments
621         val builder = uri.buildUpon()
622         builder.path(null)
623         for (segment in pathSegments) {
624           if (ExponentManifest.DEEP_LINK_SEPARATOR == segment) {
625             break
626           }
627           builder.appendEncodedPath(segment)
628         }
629         builder.appendEncodedPath(ExponentManifest.DEEP_LINK_SEPARATOR_WITH_SLASH).build()
630           .toString()
631       } else {
632         manifestUrl
633       }
634     }
635 
636   companion object {
637     private val TAG = ReactNativeActivity::class.java.simpleName
638     private const val VIEW_TEST_INTERVAL_MS: Long = 20
639     @JvmStatic protected var errorQueue: Queue<ExponentError> = LinkedList()
640   }
641 }
642