Added buffering to prevent heavy logging issues

src/serialmonitor/outputBuffer.ts

@@ -0,0 +1,44 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license.
+
+import { performance } from "perf_hooks";
+import * as vscode from "vscode";
+
+export class BufferedOutputChannel implements vscode.Disposable {
+    private _buffer: string[];
+    private _timer: NodeJS.Timer;
+    private _lastFlushTime: number;
+
+    public constructor(private readonly outputCallback: (value: string) => void, private readonly flushIntervalMs: number) {
+        this._buffer = [];
+        this._timer = setInterval(() => this.tryFlush(), this.flushIntervalMs);
+        this._lastFlushTime = Number.NEGATIVE_INFINITY;
+    }
+
+    public append(value: string) {
+        this.add(value);
+    }
+
+    public appendLine(value: string) {
+        this.add(value + "\n");
+    }
+
+    public dispose() {
+        this.tryFlush();
+        clearInterval(this._timer);
+    }
+
+    private add(value: string) {
+        this._buffer.push(value);
+        this.tryFlush();
+    }
+
+    private tryFlush() {
+        const currentTime = performance.now();
+        if (this._buffer.length > 0 && currentTime - this._lastFlushTime > this.flushIntervalMs) {
+            this.outputCallback(this._buffer.join(""));
+            this._lastFlushTime = currentTime;
+            this._buffer = [];
+        }
+    }
+}

src/serialmonitor/serialMonitor.ts

@@ -6,6 +6,7 @@ import ArduinoContext from "../arduinoContext";
 import * as constants from "../common/constants";
 import { DeviceContext } from "../deviceContext";
 import * as Logger from "../logger/logger";
+import { BufferedOutputChannel } from "./outputBuffer";
 import { SerialPortCtrl } from "./serialportctrl";
 
 export interface ISerialPortDetail {
@@ -49,6 +50,8 @@ export class SerialMonitor implements vscode.Disposable {
 
     private _outputChannel: vscode.OutputChannel;
 
+    private _bufferedOutputChannel: BufferedOutputChannel;
+
     public initialize() {
         let defaultBaudRate;
         if (ArduinoContext.arduinoApp && ArduinoContext.arduinoApp.settings && ArduinoContext.arduinoApp.settings.defaultBaudRate) {
@@ -57,6 +60,7 @@ export class SerialMonitor implements vscode.Disposable {
             defaultBaudRate = SerialMonitor.DEFAULT_BAUD_RATE;
         }
         this._outputChannel = vscode.window.createOutputChannel(SerialMonitor.SERIAL_MONITOR);
+        this._bufferedOutputChannel = new BufferedOutputChannel(this._outputChannel.append, 300);
         this._currentBaudRate = defaultBaudRate;
         this._portsStatusBar = vscode.window.createStatusBarItem(vscode.StatusBarAlignment.Right, constants.statusBarPriority.PORT);
         this._portsStatusBar.command = "arduino.selectSerialPort";
@@ -88,6 +92,8 @@ export class SerialMonitor implements vscode.Disposable {
         if (this._serialPortCtrl && this._serialPortCtrl.isActive) {
             return this._serialPortCtrl.stop();
         }
+        this._outputChannel.dispose();
+        this._bufferedOutputChannel.dispose();
     }
 
     public async selectSerialPort(vid: string, pid: string) {
@@ -145,7 +151,11 @@ export class SerialMonitor implements vscode.Disposable {
                 return;
             }
         } else {
-            this._serialPortCtrl = new SerialPortCtrl(this._currentPort, this._currentBaudRate, this._outputChannel);
+            this._serialPortCtrl = new SerialPortCtrl(
+                this._currentPort,
+                this._currentBaudRate,
+                this._bufferedOutputChannel,
+                this._outputChannel.show);
         }
 
         if (!this._serialPortCtrl.currentPort) {

src/serialmonitor/serialportctrl.ts

@@ -4,8 +4,8 @@
 import { ChildProcess, execFileSync, spawn  } from "child_process";
 import * as os from "os";
 import * as path from "path";
-import { OutputChannel } from "vscode";
 import { DeviceContext } from "../deviceContext";
+import { BufferedOutputChannel } from "./outputBuffer";
 
 interface ISerialPortDetail {
   port: string;
@@ -63,7 +63,11 @@ export class SerialPortCtrl {
   private _currentBaudRate: number;
   private _currentSerialPort = null;
 
-  public constructor(port: string, baudRate: number, private _outputChannel: OutputChannel) {
+  public constructor(
+      port: string,
+      baudRate: number,
+      private _bufferedOutputChannel: BufferedOutputChannel,
+      private showOutputChannel: (preserveFocus?: boolean) => void) {
     this._currentBaudRate = baudRate;
     this._currentPort = port;
   }
@@ -80,8 +84,8 @@ export class SerialPortCtrl {
   }
 
   public open(): Promise<void> {
-    this._outputChannel.appendLine(`[Starting] Opening the serial port - ${this._currentPort}`);
-    this._outputChannel.show();
+    this._bufferedOutputChannel.appendLine(`[Starting] Opening the serial port - ${this._currentPort}`);
+    this.showOutputChannel();
 
     if (this._child) {
         this.stop();
@@ -96,8 +100,10 @@ export class SerialPortCtrl {
         });
 
         this._child.stdout.on("data", (data) => {
-            const jsonObj = JSON.parse(data.toString())
-            this._outputChannel.append(jsonObj["payload"] + "\n");
+            if (this.isActive) {
+                const jsonObj = JSON.parse(data.toString())
+                this._bufferedOutputChannel.append(jsonObj["payload"] + "\n");
+            }
         });
         // TODO: add message check to ensure _child spawned without errors
         resolve();
@@ -155,8 +161,8 @@ export class SerialPortCtrl {
       }
       try {
         this._child.stdin.write('{"cmd": "close"}\n');
-        if (this._outputChannel) {
-          this._outputChannel.appendLine(`[Done] Closed the serial port ${os.EOL}`);
+        if (this._bufferedOutputChannel) {
+          this._bufferedOutputChannel.appendLine(`[Done] Closed the serial port ${os.EOL}`);
         }
         this._child = null;
         resolve(true);