From 714513083560612b30f127a36f6a366f2d84977e Mon Sep 17 00:00:00 2001
From: Daniel Imms <daimms@microsoft.com>
Date: Tue, 5 Jan 2021 09:32:09 -0800
Subject: [PATCH] Fix onBufferChange event not working after reset

Co-authored-by: Megan Rogge (megan.rogge@microsoft.com)
---
 src/browser/public/Terminal.ts       | 19 +++++++++----------
 src/common/buffer/BufferSet.ts       | 18 ++++++++++--------
 src/common/buffer/Types.d.ts         |  1 +
 src/common/services/BufferService.ts |  3 +--
 4 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/src/browser/public/Terminal.ts b/src/browser/public/Terminal.ts
index 517f7c4f..70247f88 100644
--- a/src/browser/public/Terminal.ts
+++ b/src/browser/public/Terminal.ts
@@ -60,9 +60,8 @@ export class Terminal implements ITerminalApi {
   public get cols(): number { return this._core.cols; }
   public get buffer(): IBufferNamespaceApi {
     this._checkProposedApi();
-    this._core.reset();
     if (!this._buffer) {
-      this._buffer = new BufferNamespaceApi(this._core.buffers);
+      this._buffer = new BufferNamespaceApi(this._core);
     }
     return this._buffer;
   }
@@ -251,21 +250,21 @@ class BufferNamespaceApi implements IBufferNamespaceApi {
   private _onBufferChange = new EventEmitter<IBufferApi>();
   public get onBufferChange(): IEvent<IBufferApi> { return this._onBufferChange.event; }
 
-  constructor(private _buffers: IBufferSet) {
-    this._normal = new BufferApiView(this._buffers.normal, 'normal');
-    this._alternate = new BufferApiView(this._buffers.alt, 'alternate');
-    this._buffers.onBufferActivate(() => this._onBufferChange.fire(this.active));
+  constructor(private _core: ITerminal) {
+    this._normal = new BufferApiView(this._core.buffers.normal, 'normal');
+    this._alternate = new BufferApiView(this._core.buffers.alt, 'alternate');
+    this._core.buffers.onBufferActivate(() => this._onBufferChange.fire(this.active));
   }
   public get active(): IBufferApi {
-    if (this._buffers.active === this._buffers.normal) { return this.normal; }
-    if (this._buffers.active === this._buffers.alt) { return this.alternate; }
+    if (this._core.buffers.active === this._core.buffers.normal) { return this.normal; }
+    if (this._core.buffers.active === this._core.buffers.alt) { return this.alternate; }
     throw new Error('Active buffer is neither normal nor alternate');
   }
   public get normal(): IBufferApi {
-    return this._normal.init(this._buffers.normal);
+    return this._normal.init(this._core.buffers.normal);
   }
   public get alternate(): IBufferApi {
-    return this._alternate.init(this._buffers.alt);
+    return this._alternate.init(this._core.buffers.alt);
   }
 }
 
diff --git a/src/common/buffer/BufferSet.ts b/src/common/buffer/BufferSet.ts
index b9dc7995..b74c4eac 100644
--- a/src/common/buffer/BufferSet.ts
+++ b/src/common/buffer/BufferSet.ts
@@ -15,10 +15,9 @@ import { Disposable } from 'common/Lifecycle';
  * provides also utilities for working with them.
  */
 export class BufferSet extends Disposable implements IBufferSet {
-  private _normal: Buffer;
-  private _alt: Buffer;
-  private _activeBuffer: Buffer;
-
+  private _normal!: Buffer;
+  private _alt!: Buffer;
+  private _activeBuffer!: Buffer;
 
   private _onBufferActivate = this.register(new EventEmitter<{activeBuffer: IBuffer, inactiveBuffer: IBuffer}>());
   public get onBufferActivate(): IEvent<{activeBuffer: IBuffer, inactiveBuffer: IBuffer}> { return this._onBufferActivate.event; }
@@ -28,17 +27,20 @@ export class BufferSet extends Disposable implements IBufferSet {
    * @param _terminal - The terminal the BufferSet will belong to
    */
   constructor(
-    optionsService: IOptionsService,
-    bufferService: IBufferService
+    private readonly _optionsService: IOptionsService,
+    private readonly _bufferService: IBufferService
   ) {
     super();
+    this.reset();
+  }
 
-    this._normal = new Buffer(true, optionsService, bufferService);
+  public reset(): void {
+    this._normal = new Buffer(true, this._optionsService, this._bufferService);
     this._normal.fillViewportRows();
 
     // The alt buffer should never have scrollback.
     // See http://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h2-The-Alternate-Screen-Buffer
-    this._alt = new Buffer(false, optionsService, bufferService);
+    this._alt = new Buffer(false, this._optionsService, this._bufferService);
     this._activeBuffer = this._normal;
 
     this.setupTabStops();
diff --git a/src/common/buffer/Types.d.ts b/src/common/buffer/Types.d.ts
index 752b1a26..cbf40a03 100644
--- a/src/common/buffer/Types.d.ts
+++ b/src/common/buffer/Types.d.ts
@@ -56,6 +56,7 @@ export interface IBufferSet extends IDisposable {
 
   activateNormalBuffer(): void;
   activateAltBuffer(fillAttr?: IAttributeData): void;
+  reset(): void;
   resize(newCols: number, newRows: number): void;
   setupTabStops(i?: number): void;
 }
diff --git a/src/common/services/BufferService.ts b/src/common/services/BufferService.ts
index 301146e1..47e54729 100644
--- a/src/common/services/BufferService.ts
+++ b/src/common/services/BufferService.ts
@@ -49,8 +49,7 @@ export class BufferService extends Disposable implements IBufferService {
   }
 
   public reset(): void {
-    this.buffers.dispose();
-    this.buffers = new BufferSet(this._optionsService, this);
+    this.buffers.reset();
     this.isUserScrolling = false;
   }
 }