Bug 1772096 - Part 6: Use plain object for lazy getter in remote/shared/messagehandler/. r=webdriver-reviewers,jdescottes

Differential Revision: https://phabricator.services.mozilla.com/D148003

remote/shared/messagehandler/MessageHandler.jsm

@@ -10,7 +10,9 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   EventEmitter: "resource://gre/modules/EventEmitter.jsm",
 
   error: "chrome://remote/content/shared/messagehandler/Errors.jsm",
@@ -20,7 +22,7 @@ XPCOMUtils.defineLazyModuleGetters(this, {
   ModuleCache: "chrome://remote/content/shared/messagehandler/ModuleCache.jsm",
 });
 
-XPCOMUtils.defineLazyGetter(this, "logger", () => Log.get());
+XPCOMUtils.defineLazyGetter(lazy, "logger", () => lazy.Log.get());
 
 /**
  * A ContextDescriptor object provides information to decide if a broadcast or
@@ -77,7 +79,7 @@ const ContextDescriptorType = {
  * instances are properly registered and can be retrieved based on a given
  * session id as well as some other context information.
  */
-class MessageHandler extends EventEmitter {
+class MessageHandler extends lazy.EventEmitter {
   /**
    * Create a new MessageHandler instance.
    *
@@ -89,12 +91,12 @@ class MessageHandler extends EventEmitter {
   constructor(sessionId, context) {
     super();
 
-    this._moduleCache = new ModuleCache(this);
+    this._moduleCache = new lazy.ModuleCache(this);
 
     this._sessionId = sessionId;
     this._context = context;
     this._contextId = this.constructor.getIdFromContext(context);
-    this._eventsDispatcher = new EventsDispatcher(this);
+    this._eventsDispatcher = new lazy.EventsDispatcher(this);
   }
 
   get contextId() {
@@ -114,7 +116,7 @@ class MessageHandler extends EventEmitter {
   }
 
   destroy() {
-    logger.trace(
+    lazy.logger.trace(
       `MessageHandler ${this.constructor.type} for session ${this.sessionId} is being destroyed`
     );
     this._eventsDispatcher.destroy();
@@ -214,12 +216,12 @@ class MessageHandler extends EventEmitter {
    */
   handleCommand(command) {
     const { moduleName, commandName, params, destination } = command;
-    logger.trace(
+    lazy.logger.trace(
       `Received command ${moduleName}.${commandName} for destination ${destination.type}`
     );
 
     if (!this.supportsCommand(moduleName, commandName, destination)) {
-      throw new error.UnsupportedCommandError(
+      throw new lazy.error.UnsupportedCommandError(
         `${moduleName}.${commandName} not supported for destination ${destination?.type}`
       );
     }

remote/shared/messagehandler/MessageHandlerRegistry.jsm

@@ -10,7 +10,9 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   EventEmitter: "resource://gre/modules/EventEmitter.jsm",
 
   Log: "chrome://remote/content/shared/Log.jsm",
@@ -22,18 +24,18 @@ XPCOMUtils.defineLazyModuleGetters(this, {
     "chrome://remote/content/shared/messagehandler/WindowGlobalMessageHandler.jsm",
 });
 
-XPCOMUtils.defineLazyGetter(this, "logger", () => Log.get());
+XPCOMUtils.defineLazyGetter(lazy, "logger", () => lazy.Log.get());
 
 /**
  * Map of MessageHandler type to MessageHandler subclass.
  */
 XPCOMUtils.defineLazyGetter(
-  this,
+  lazy,
   "MessageHandlerClasses",
   () =>
     new Map([
-      [RootMessageHandler.type, RootMessageHandler],
-      [WindowGlobalMessageHandler.type, WindowGlobalMessageHandler],
+      [lazy.RootMessageHandler.type, lazy.RootMessageHandler],
+      [lazy.WindowGlobalMessageHandler.type, lazy.WindowGlobalMessageHandler],
     ])
 );
 
@@ -48,10 +50,10 @@ XPCOMUtils.defineLazyGetter(
  *      Throws if no MessageHandler subclass is found for the provided type.
  */
 function getMessageHandlerClass(type) {
-  if (!MessageHandlerClasses.has(type)) {
+  if (!lazy.MessageHandlerClasses.has(type)) {
     throw new Error(`No MessageHandler class available for type "${type}"`);
   }
-  return MessageHandlerClasses.get(type);
+  return lazy.MessageHandlerClasses.get(type);
 }
 
 /**
@@ -66,7 +68,7 @@ function getMessageHandlerClass(type) {
  * The registry is useful to retrieve the appropriate MessageHandler instance
  * after crossing a technical boundary (eg process, thread...).
  */
-class MessageHandlerRegistry extends EventEmitter {
+class MessageHandlerRegistry extends lazy.EventEmitter {
   /*
    * @param {String} type
    *     MessageHandler type, one of MessageHandler.type.
@@ -98,7 +100,7 @@ class MessageHandlerRegistry extends EventEmitter {
    * to receive/send commands.
    */
   createAllMessageHandlers() {
-    const data = readSessionData();
+    const data = lazy.readSessionData();
     for (const [sessionId, sessionDataItems] of data) {
       // Create a message handler for this context for each active message
       // handler session.
@@ -176,7 +178,7 @@ class MessageHandlerRegistry extends EventEmitter {
   getRootMessageHandler(sessionId) {
     const rootMessageHandler = this.getExistingMessageHandler(
       sessionId,
-      RootMessageHandler.type
+      lazy.RootMessageHandler.type
     );
     if (!rootMessageHandler) {
       throw new Error(
@@ -217,7 +219,7 @@ class MessageHandlerRegistry extends EventEmitter {
 
     this._messageHandlersMap.set(sessionId, messageHandler);
 
-    logger.trace(
+    lazy.logger.trace(
       `Created MessageHandler ${this._type} for session ${sessionId}`
     );
 
@@ -234,7 +236,7 @@ class MessageHandlerRegistry extends EventEmitter {
     messageHandler.off("message-handler-event", this._onMessageHandlerEvent);
     this._messageHandlersMap.delete(messageHandler.sessionId);
 
-    logger.trace(
+    lazy.logger.trace(
       `Unregistered MessageHandler ${messageHandler.constructor.type} for session ${messageHandler.sessionId}`
     );
   }

remote/shared/messagehandler/ModuleCache.jsm

@@ -11,7 +11,9 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   getMessageHandlerClass:
     "chrome://remote/content/shared/messagehandler/MessageHandlerRegistry.jsm",
   // Additional protocols might use a different registry for their modules,
@@ -23,13 +25,13 @@ XPCOMUtils.defineLazyModuleGetters(this, {
 });
 
 XPCOMUtils.defineLazyModuleGetter(
-  this,
+  lazy,
   "getTestModuleClass",
   "chrome://mochitests/content/browser/remote/shared/messagehandler/test/browser/resources/modules/ModuleRegistry.jsm",
   "getModuleClass"
 );
 
-XPCOMUtils.defineLazyGetter(this, "logger", () => Log.get());
+XPCOMUtils.defineLazyGetter(lazy, "logger", () => lazy.Log.get());
 
 /**
  * ModuleCache instances are dedicated to lazily create and cache the instances
@@ -154,11 +156,11 @@ class ModuleCache {
     let module = null;
     if (ModuleClass) {
       module = new ModuleClass(this.messageHandler);
-      logger.trace(
+      lazy.logger.trace(
         `Module ${moduleFolder}/${moduleName}.jsm found for ${destination.type}`
       );
     } else {
-      logger.trace(
+      lazy.logger.trace(
         `Module ${moduleFolder}/${moduleName}.jsm not found for ${destination.type}`
       );
     }
@@ -188,16 +190,16 @@ class ModuleCache {
 
   _getModuleClass(moduleName, moduleFolder) {
     if (this._useTestModules) {
-      return getTestModuleClass(moduleName, moduleFolder);
+      return lazy.getTestModuleClass(moduleName, moduleFolder);
     }
 
     // Retrieve the module class from the WebDriverBiDi ModuleRegistry if we
     // are not using test modules.
-    return getModuleClass(moduleName, moduleFolder);
+    return lazy.getModuleClass(moduleName, moduleFolder);
   }
 
   _getModuleFolder(originType, destinationType) {
-    const originPath = getMessageHandlerClass(originType).modulePath;
+    const originPath = lazy.getMessageHandlerClass(originType).modulePath;
     if (originType === destinationType) {
       // If the command is targeting the current type, the module is expected to
       // be in eg "windowglobal/${moduleName}.jsm".
@@ -205,7 +207,8 @@ class ModuleCache {
     }
     // If the command is targeting another type, the module is expected to
     // be in a composed folder eg "windowglobal-in-root/${moduleName}.jsm".
-    const destinationPath = getMessageHandlerClass(destinationType).modulePath;
+    const destinationPath = lazy.getMessageHandlerClass(destinationType)
+      .modulePath;
     return `${destinationPath}-in-${originPath}`;
   }
 }

remote/shared/messagehandler/RootMessageHandler.jsm

@@ -10,7 +10,9 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   FrameTransport:
     "chrome://remote/content/shared/messagehandler/transports/FrameTransport.jsm",
   MessageHandler:
@@ -26,7 +28,7 @@ XPCOMUtils.defineLazyModuleGetters(this, {
  * in the parent process. It can forward commands to MessageHandlers in other
  * layers (at the moment WindowGlobalMessageHandlers in content processes).
  */
-class RootMessageHandler extends MessageHandler {
+class RootMessageHandler extends lazy.MessageHandler {
   /**
    * Returns the RootMessageHandler module path.
    *
@@ -62,8 +64,8 @@ class RootMessageHandler extends MessageHandler {
   constructor(sessionId) {
     super(sessionId, null);
 
-    this._frameTransport = new FrameTransport(this);
-    this._sessionData = new SessionData(this);
+    this._frameTransport = new lazy.FrameTransport(this);
+    this._sessionData = new lazy.SessionData(this);
   }
 
   get sessionData() {
@@ -98,7 +100,7 @@ class RootMessageHandler extends MessageHandler {
    */
   forwardCommand(command) {
     switch (command.destination.type) {
-      case WindowGlobalMessageHandler.type:
+      case lazy.WindowGlobalMessageHandler.type:
         return this._frameTransport.forwardCommand(command);
       default:
         throw new Error(
@@ -145,7 +147,7 @@ class RootMessageHandler extends MessageHandler {
     }
 
     const destination = {
-      type: WindowGlobalMessageHandler.type,
+      type: lazy.WindowGlobalMessageHandler.type,
       contextDescriptor,
     };
 

remote/shared/messagehandler/RootMessageHandlerRegistry.jsm

@@ -10,7 +10,9 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   MessageHandlerRegistry:
     "chrome://remote/content/shared/messagehandler/MessageHandlerRegistry.jsm",
   RootMessageHandler:
@@ -23,6 +25,6 @@ XPCOMUtils.defineLazyModuleGetters(this, {
  * registry and from there either create or retrieve Root MessageHandler
  * instances for a specific session.
  */
-var RootMessageHandlerRegistry = new MessageHandlerRegistry(
-  RootMessageHandler.type
+var RootMessageHandlerRegistry = new lazy.MessageHandlerRegistry(
+  lazy.RootMessageHandler.type
 );

remote/shared/messagehandler/WindowGlobalMessageHandler.jsm

@@ -10,7 +10,9 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   ContextDescriptorType:
     "chrome://remote/content/shared/messagehandler/MessageHandler.jsm",
   MessageHandler:
@@ -24,7 +26,7 @@ XPCOMUtils.defineLazyModuleGetters(this, {
  * commands further to other MessageHandlers and represents a leaf node in a
  * MessageHandler network.
  */
-class WindowGlobalMessageHandler extends MessageHandler {
+class WindowGlobalMessageHandler extends lazy.MessageHandler {
   constructor() {
     super(...arguments);
 
@@ -129,8 +131,9 @@ class WindowGlobalMessageHandler extends MessageHandler {
 
   _matchesContext(contextDescriptor) {
     return (
-      contextDescriptor.type === ContextDescriptorType.All ||
-      (contextDescriptor.type === ContextDescriptorType.TopBrowsingContext &&
+      contextDescriptor.type === lazy.ContextDescriptorType.All ||
+      (contextDescriptor.type ===
+        lazy.ContextDescriptorType.TopBrowsingContext &&
         contextDescriptor.id === this._context.browserId)
     );
   }

remote/shared/messagehandler/sessiondata/SessionData.jsm

@@ -11,7 +11,9 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   ContextDescriptorType:
     "chrome://remote/content/shared/messagehandler/MessageHandler.jsm",
   Log: "chrome://remote/content/shared/Log.jsm",
@@ -19,7 +21,7 @@ XPCOMUtils.defineLazyModuleGetters(this, {
     "chrome://remote/content/shared/messagehandler/RootMessageHandler.jsm",
 });
 
-XPCOMUtils.defineLazyGetter(this, "logger", () => Log.get());
+XPCOMUtils.defineLazyGetter(lazy, "logger", () => lazy.Log.get());
 
 const SESSION_DATA_SHARED_DATA_KEY = "MessageHandlerSessionData";
 
@@ -87,7 +89,7 @@ const sessionDataMap = new Map();
  */
 class SessionData {
   constructor(messageHandler) {
-    if (messageHandler.constructor.type != RootMessageHandler.type) {
+    if (messageHandler.constructor.type != lazy.RootMessageHandler.type) {
       throw new Error(
         "SessionData should only be used from a ROOT MessageHandler"
       );
@@ -136,7 +138,7 @@ class SessionData {
         this._data.push(item);
         addedValues.push(value);
       } else {
-        logger.warn(
+        lazy.logger.warn(
           `Duplicated session data item was not added: ${JSON.stringify(item)}`
         );
       }
@@ -215,7 +217,7 @@ class SessionData {
         this._data.splice(itemIndex, 1);
         removedValues.push(value);
       } else {
-        logger.warn(
+        lazy.logger.warn(
           `Missing session data item was not removed: ${JSON.stringify(item)}`
         );
       }
@@ -245,7 +247,7 @@ class SessionData {
   }
 
   _isSameContextDescriptor(contextDescriptor1, contextDescriptor2) {
-    if (contextDescriptor1.type === ContextDescriptorType.All) {
+    if (contextDescriptor1.type === lazy.ContextDescriptorType.All) {
       // Ignore the id for type "all" since we made the id optional for this type.
       return contextDescriptor1.type === contextDescriptor2.type;
     }

remote/shared/messagehandler/sessiondata/SessionDataReader.jsm

@@ -11,12 +11,14 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   SESSION_DATA_SHARED_DATA_KEY:
     "chrome://remote/content/shared/messagehandler/sessiondata/SessionData.jsm",
 });
 
-XPCOMUtils.defineLazyGetter(this, "sharedData", () => {
+XPCOMUtils.defineLazyGetter(lazy, "sharedData", () => {
   const isInParent =
     Services.appinfo.processType == Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT;
 
@@ -31,4 +33,4 @@ XPCOMUtils.defineLazyGetter(this, "sharedData", () => {
  *     Map of session id to arrays of SessionDataItems.
  */
 const readSessionData = () =>
-  sharedData.get(SESSION_DATA_SHARED_DATA_KEY) || new Map();
+  lazy.sharedData.get(lazy.SESSION_DATA_SHARED_DATA_KEY) || new Map();

remote/shared/messagehandler/transports/FrameTransport.jsm

@@ -6,13 +6,14 @@
 
 const EXPORTED_SYMBOLS = ["FrameTransport"];
 
+const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
-  Services: "resource://gre/modules/Services.jsm",
+const lazy = {};
 
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   ContextDescriptorType:
     "chrome://remote/content/shared/messagehandler/MessageHandler.jsm",
   isBrowsingContextCompatible:
@@ -23,7 +24,7 @@ XPCOMUtils.defineLazyModuleGetters(this, {
   TabManager: "chrome://remote/content/shared/TabManager.jsm",
 });
 
-XPCOMUtils.defineLazyGetter(this, "logger", () => Log.get());
+XPCOMUtils.defineLazyGetter(this, "logger", () => lazy.Log.get());
 
 const MAX_RETRY_ATTEMPTS = 10;
 
@@ -42,7 +43,7 @@ class FrameTransport {
 
     // FrameTransport will rely on the MessageHandlerFrame JSWindow actors.
     // Make sure they are registered when instanciating a FrameTransport.
-    MessageHandlerFrameActor.register();
+    lazy.MessageHandlerFrameActor.register();
   }
 
   /**
@@ -154,11 +155,11 @@ class FrameTransport {
   _getBrowsingContextsForDescriptor(contextDescriptor) {
     const { id, type } = contextDescriptor;
 
-    if (type === ContextDescriptorType.All) {
+    if (type === lazy.ContextDescriptorType.All) {
       return this._getBrowsingContexts();
     }
 
-    if (type === ContextDescriptorType.TopBrowsingContext) {
+    if (type === lazy.ContextDescriptorType.TopBrowsingContext) {
       return this._getBrowsingContexts({ browserId: id });
     }
 
@@ -184,8 +185,8 @@ class FrameTransport {
     let browsingContexts = [];
 
     // Fetch all tab related browsing contexts for top-level windows.
-    for (const { browsingContext } of TabManager.browsers) {
-      if (isBrowsingContextCompatible(browsingContext, { browserId })) {
+    for (const { browsingContext } of lazy.TabManager.browsers) {
+      if (lazy.isBrowsingContextCompatible(browsingContext, { browserId })) {
         browsingContexts = browsingContexts.concat(
           browsingContext.getAllBrowsingContextsInSubtree()
         );

remote/shared/messagehandler/transports/js-window-actors/MessageHandlerFrameActor.jsm

@@ -10,12 +10,14 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   ActorManagerParent: "resource://gre/modules/ActorManagerParent.jsm",
 
   Log: "chrome://remote/content/shared/Log.jsm",
 });
-XPCOMUtils.defineLazyGetter(this, "logger", () => Log.get());
+XPCOMUtils.defineLazyGetter(lazy, "logger", () => lazy.Log.get());
 
 const FRAME_ACTOR_CONFIG = {
   parent: {
@@ -45,10 +47,10 @@ const MessageHandlerFrameActor = {
       return;
     }
 
-    ActorManagerParent.addJSWindowActors({
+    lazy.ActorManagerParent.addJSWindowActors({
       MessageHandlerFrame: FRAME_ACTOR_CONFIG,
     });
     this.registered = true;
-    logger.trace("Registered MessageHandlerFrame actors");
+    lazy.logger.trace("Registered MessageHandlerFrame actors");
   },
 };

remote/shared/messagehandler/transports/js-window-actors/MessageHandlerFrameChild.jsm

@@ -10,7 +10,9 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   error: "chrome://remote/content/shared/messagehandler/Errors.jsm",
   isBrowsingContextCompatible:
     "chrome://remote/content/shared/messagehandler/transports/FrameContextUtils.jsm",
@@ -27,10 +29,10 @@ XPCOMUtils.defineLazyModuleGetters(this, {
  */
 class MessageHandlerFrameChild extends JSWindowActorChild {
   actorCreated() {
-    this.type = WindowGlobalMessageHandler.type;
+    this.type = lazy.WindowGlobalMessageHandler.type;
     this.context = this.manager.browsingContext;
 
-    this._registry = new MessageHandlerRegistry(this.type, this.context);
+    this._registry = new lazy.MessageHandlerRegistry(this.type, this.context);
     this._onRegistryEvent = this._onRegistryEvent.bind(this);
 
     // MessageHandlerFrameChild is responsible for forwarding events from
@@ -42,7 +44,7 @@ class MessageHandlerFrameChild extends JSWindowActorChild {
 
   handleEvent({ type }) {
     if (type == "DOMWindowCreated") {
-      if (isBrowsingContextCompatible(this.manager.browsingContext)) {
+      if (lazy.isBrowsingContextCompatible(this.manager.browsingContext)) {
         this._registry.createAllMessageHandlers();
       }
     }
@@ -57,7 +59,7 @@ class MessageHandlerFrameChild extends JSWindowActorChild {
       try {
         return await messageHandler.handleCommand(command);
       } catch (e) {
-        if (e instanceof error.MessageHandlerError) {
+        if (e instanceof lazy.error.MessageHandlerError) {
           return {
             error: e.toJSON(),
           };

remote/shared/messagehandler/transports/js-window-actors/MessageHandlerFrameParent.jsm

@@ -10,7 +10,9 @@ const { XPCOMUtils } = ChromeUtils.import(
   "resource://gre/modules/XPCOMUtils.jsm"
 );
 
-XPCOMUtils.defineLazyModuleGetters(this, {
+const lazy = {};
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
   error: "chrome://remote/content/shared/messagehandler/Errors.jsm",
   RootMessageHandlerRegistry:
     "chrome://remote/content/shared/messagehandler/RootMessageHandlerRegistry.jsm",
@@ -28,7 +30,7 @@ class MessageHandlerFrameParent extends JSWindowActorParent {
         const { name, data, isProtocolEvent, sessionId } = message.data;
 
         // Re-emit the event on the RootMessageHandler.
-        const messageHandler = RootMessageHandlerRegistry.getExistingMessageHandler(
+        const messageHandler = lazy.RootMessageHandlerRegistry.getExistingMessageHandler(
           sessionId
         );
         messageHandler.emitEvent(name, data, { isProtocolEvent });
@@ -61,7 +63,7 @@ class MessageHandlerFrameParent extends JSWindowActorParent {
     );
 
     if (result?.error) {
-      throw error.MessageHandlerError.fromJSON(result.error);
+      throw lazy.error.MessageHandlerError.fromJSON(result.error);
     }
 
     return result;