better flow + handle unclosed connection (#921)

* better flow + handle unclosed connection

* more checks

editor/deploy.ts

@@ -65,9 +65,12 @@ class WebSerialPackageIO implements pxt.HF2.PacketIO {
     }
 
     async readSerialAsync() {
+        if (this._reader) return;
+
         this._reader = this.port.readable.getReader();
         let buffer: Uint8Array;
-        while (!!this._reader) {
+        const reader = this._reader;
+        while (reader === this._reader) { // will change if we recycle the connection
             const { done, value } = await this._reader.read()
             if (!buffer) buffer = value;
             else { // concat
@@ -112,8 +115,18 @@ class WebSerialPackageIO implements pxt.HF2.PacketIO {
         throw new Error(lf("error on brick ({0})", msg))
     }
 
+    private close() {
+        if (this.port.readable) {// it's open
+            this.port.close();
+            this._reader = undefined;
+            this._writer = undefined;
+        }
+    }
+
     async reconnectAsync(): Promise<void> {
-        if (!this._reader) {
+        if (!this.port.readable) {
+            this._reader = undefined;
+            this._writer = undefined;
             await this.port.open(this.options);
             this.readSerialAsync();
         }
@@ -121,9 +134,7 @@ class WebSerialPackageIO implements pxt.HF2.PacketIO {
     }
 
     async disconnectAsync(): Promise<void> {
-        this.port.close();
-        this._reader = undefined;
-        this._writer = undefined;
+        this.close();
         return Promise.resolve();
     }
 
@@ -171,6 +182,8 @@ export function enableWebSerial() {
     initPromise = undefined;
     useWebSerial = WebSerialPackageIO.isSupported();
     useHID = useWebSerial;
+    if (useWebSerial)
+        initHidAsync().done();
 }
 
 let initPromise: Promise<Ev3Wrapper>

editor/extension.ts

@@ -80,7 +80,6 @@ pxt.editor.initExtensionsAsync = function (opts: pxt.editor.ExtensionOptions): P
                     className: "bluetooth focused",
                     onclick: () => {
                         pxt.tickEvent("bluetooth.enable");
-                        enableWebSerial();
                         confirmAsync({
                             header: lf("Bluetooth enabled"),
                             hasCloseIcon: true,
@@ -93,7 +92,7 @@ pxt.editor.initExtensionsAsync = function (opts: pxt.editor.ExtensionOptions): P
                             }],
                             htmlBody: `
 <p>
-${lf("Please download again to send your code to the EV3 over Bluetooth.")}
+${lf("Download again to send your code to the EV3 over Bluetooth. Make sure to stop your program!")}
 </p>
 <p>
 ${lf("You will be prompted to select a serial port.")}
@@ -101,6 +100,8 @@ ${lf("On Windows, look for 'Standard Serial over Bluetooth link'.")}
 ${lf("If you have paired multiple EV3, you might have to try out multiple ports until you find the correct one.")}
 </p>
 `
+                        }).then(() => {
+                            enableWebSerial();
                         })
                     }
                 } : undefined, downloadAgain ? {

libs/core/input.ts

@@ -310,7 +310,7 @@ void      cUiUpdatePower(void)
                 // TODO? for now assume touch
                 sensorInfo.devType = DAL.DEVICE_TYPE_TOUCH
             } else if (newConn == DAL.CONN_NONE || newConn == 0) {
-                control.dmesg(`disconnect at port ${sensorInfo.port}`)
+                //control.dmesg(`disconnect at port ${sensorInfo.port}`)
             } else {
                 control.dmesg(`unknown connection type: ${newConn} at ${sensorInfo.port}`)
             }
@@ -328,7 +328,7 @@ void      cUiUpdatePower(void)
         if (numChanged == 0 && nonActivated == 0)
             return
 
-        control.dmesg(`updating sensor status`)
+        //control.dmesg(`updating sensor status`)
         nonActivated = 0;
         for (const sensorInfo of sensorInfos) {
             if (sensorInfo.devType == DAL.DEVICE_TYPE_IIC_UNKNOWN) {