Revert this commit after branch create

Author: stricklandrbls

src/dataEditor/dataEditorClient.ts

@@ -85,6 +85,7 @@ import * as child_process from 'child_process'
 import { osCheck } from '../utils'
 import { getCurrentConfig } from '../utils'
 import { isDFDLDebugSessionActive } from './include/utils'
+import { ViewoprtState } from './include/changes/changeMemento'
 
 // *****************************************************************************
 // global constants
@@ -136,6 +137,7 @@ export function activate(ctx: vscode.ExtensionContext): void {
 // *****************************************************************************
 
 export class DataEditorClient implements vscode.Disposable {
+  private mementoState: ViewoprtState | undefined = undefined
   public panel: vscode.WebviewPanel
   private svelteWebviewInitializer: SvelteWebviewInitializer
   private displayState: DisplayState
@@ -296,6 +298,8 @@ export class DataEditorClient implements vscode.Disposable {
     return this.omegaSessionId
   }
 
+  private restoreState(state: ViewoprtState) {}
+
   private async setupDataEditor() {
     assert(
       checkpointPath && checkpointPath.length > 0,
@@ -390,6 +394,7 @@ export class DataEditorClient implements vscode.Disposable {
         VIEWPORT_CAPACITY_MAX,
         false
       )
+
       this.currentViewportId = viewportDataResponse.getViewportId()
       assert(this.currentViewportId.length > 0, 'currentViewportId is not set')
       await viewportSubscribe(this.panel, this.currentViewportId)

src/dataEditor/include/changes/changeMemento.ts

@@ -0,0 +1,46 @@
+export type ViewoprtState = {
+    offset: number
+    length: number
+    bytesRemaining: number
+    data: Uint8Array
+    serial: number
+}
+export interface MementoOriginator {
+    readonly id: string
+    restore(state: ViewoprtState): void
+}
+export type MementoAttributes = {
+    currentPos: number
+    history: ViewoprtState[]
+}
+export interface MementoOperations {
+    history(): MementoAttributes['history']
+    undo(): void
+    redo(): void
+    save(): void
+}
+class SessionMemento{
+    constructor(private state: ViewoprtState){}
+    getState(){ return this.state }
+}
+
+class MementoMgr {
+    private mementoHistoryMap = new Map<string, MementoAttributes>()
+    store(originator: MementoOriginator, attr: ViewoprtState){
+        if(!this.mementoHistoryMap.get(originator.id))
+            throw ""
+        const attrs = this.mementoHistoryMap.get(originator.id)!
+        attrs.history.push(attr)
+        attrs.currentPos = attrs.history.length -1
+    }
+    undo(originator: MementoOriginator): void{
+        if(!this.mementoHistoryMap.get(originator.id))
+            throw ""
+        const attrs = this.mementoHistoryMap.get(originator.id)!
+        attrs.currentPos = attrs.history.length -1
+        originator.restore()
+    }
+
+}
+
+export function