Handle clearTerminal message by using vscode clear command (#2316)

* handle clearTerminal message by using vscode clear command

* Codacy

* changed name of setting

* delete comment

Author: TylerLeonhardt

package.json

@@ -688,6 +688,10 @@
           "default": false,
           "description": "Falls back to the legacy (lightweight) ReadLine experience. This will disable the use of PSReadLine in the PowerShell Integrated Console."
         },
+        "powershell.integratedConsole.forceClearScrollbackBuffer": {
+          "type": "boolean",
+          "description": "Use the vscode API to clear the terminal since that's the only reliable way to clear the scrollback buffer. Turn this on if you're use to 'Clear-Host' clearing scroll history as wellclear-terminal-via-lsp."
+        },
         "powershell.debugging.createTemporaryIntegratedConsole": {
           "type": "boolean",
           "default": false,

src/features/ExtensionCommands.ts

@@ -6,9 +6,11 @@ import * as fs from "fs";
 import * as os from "os";
 import * as path from "path";
 import * as vscode from "vscode";
-import { LanguageClient, NotificationType, Position, Range, RequestType } from "vscode-languageclient";
+import { LanguageClient, NotificationType, NotificationType0,
+    Position, Range, RequestType } from "vscode-languageclient";
 import { IFeature } from "../feature";
 import { Logger } from "../logging";
+import Settings = require("../settings");
 
 export interface IExtensionCommand {
     name: string;
@@ -155,6 +157,9 @@ export const SetStatusBarMessageRequestType =
     new RequestType<IStatusBarMessageDetails, EditorOperationResponse, void, void>(
         "editor/setStatusBarMessage");
 
+export const ClearTerminalNotificationType =
+        new NotificationType0("editor/clearTerminal");
+
 export interface ISaveFileDetails {
     filePath: string;
     newPath?: string;
@@ -265,6 +270,16 @@ export class ExtensionCommandsFeature implements IFeature {
             this.languageClient.onRequest(
                 SetStatusBarMessageRequestType,
                 (messageDetails) => this.setStatusBarMessage(messageDetails));
+
+            this.languageClient.onNotification(
+                ClearTerminalNotificationType,
+                () => {
+                    // We check to see if they have TrueClear on. If not, no-op because the
+                    // overriden Clear-Host already calls [System.Console]::Clear()
+                    if (Settings.load().integratedConsole.forceClearScrollbackBuffer) {
+                        vscode.commands.executeCommand("workbench.action.terminal.clear");
+                    }
+                });
         }
     }
 

src/settings.ts

@@ -99,6 +99,7 @@ export interface IIntegratedConsoleSettings {
     showOnStartup?: boolean;
     focusConsoleOnExecute?: boolean;
     useLegacyReadLine?: boolean;
+    forceClearScrollbackBuffer?: boolean;
 }
 
 export function load(): ISettings {
@@ -154,6 +155,7 @@ export function load(): ISettings {
         showOnStartup: true,
         focusConsoleOnExecute: true,
         useLegacyReadLine: false,
+        forceClearScrollbackBuffer: false,
     };
 
     return {