fix: disconnect logic on the web

Author: chmelevskij

src/js/serial_backend.js

@@ -31,9 +31,23 @@ const serial = import.meta.env ? serialWeb : serialNWJS;
 
 let mspHelper;
 let connectionTimestamp;
-let clicks = false;
 let liveDataRefreshTimerId = false;
 
+let isConnected = false;
+
+const toggleStatus = function () {
+    isConnected = !isConnected;
+};
+
+function connectHandler(event) {
+    onOpen(event.detail);
+    toggleStatus();
+}
+
+function disconnectHandler(event) {
+    onClosed(event.detail);
+}
+
 export function initializeSerialBackend() {
     GUI.updateManualPortVisibility = function() {
         const selected_port = $('div#port-picker #port option:selected');
@@ -82,10 +96,6 @@ export function initializeSerialBackend() {
         if (!GUI.connect_lock) {
             // GUI control overrides the user control
 
-            const toggleStatus = function () {
-                clicks = !clicks;
-            };
-
             GUI.configuration_loaded = false;
 
             const selected_baud = parseInt($('div#port-picker #baud').val());
@@ -94,7 +104,7 @@ export function initializeSerialBackend() {
             if (selectedPort.data().isDFU) {
                 $('select#baud').hide();
             } else if (portName !== '0') {
-                if (!clicks) {
+                if (!isConnected) {
                     console.log(`Connecting to: ${portName}`);
                     GUI.connecting_to = portName;
 
@@ -109,10 +119,13 @@ export function initializeSerialBackend() {
 
                         serial.connect('virtual', {}, onOpenVirtual);
                     } else if (import.meta.env) {
-                        serial.addEventListener('connect', (event) => {
-                            onOpen(event.detail);
-                            toggleStatus();
-                        });
+                        // Explicitly disconnect the event listeners before attaching the new ones.
+                        serial.removeEventListener('connect', connectHandler);
+                        serial.addEventListener('connect', connectHandler);
+
+                        serial.removeEventListener('disconnect', disconnectHandler);
+                        serial.addEventListener('disconnect', disconnectHandler);
+
                         serial.connect({ baudRate });
                     } else {
                         serial.connect(
@@ -276,7 +289,15 @@ function abortConnection() {
     $('div#port-picker #port, div#port-picker #baud, div#port-picker #delay').prop('disabled', false);
 
     // reset data
-    clicks = false;
+    isConnected = false;
+}
+
+/**
+ * purpose of this is to bridge the old and new api
+ * when serial events are handled.
+ */
+function read_serial_adapter(event) {
+    read_serial(event.detail.buffer);
 }
 
 function onOpen(openInfo) {
@@ -307,7 +328,8 @@ function onOpen(openInfo) {
         $('input[name="expertModeCheckbox"]').prop('checked', result).trigger('change');
 
         if(import.meta.env) {
-            serial.addEventListener('receive', (e) => read_serial(e.detail.buffer));
+            serial.removeEventListener('receive', read_serial_adapter);
+            serial.addEventListener('receive', read_serial_adapter);
         } else {
             serial.onReceive.addListener(read_serial);
         }

src/js/webSerial.js

@@ -1,9 +1,8 @@
 import { webSerialDevices } from "./serial_devices";
 
-async function* streamAsyncIterable(stream) {
-    const reader = stream.getReader();
+async function* streamAsyncIterable(reader, keepReadingFlag) {
     try {
-        while (true) {
+        while (keepReadingFlag()) {
             const { done, value } = await reader.read();
             if (done) {
                 return;
@@ -34,10 +33,20 @@ class WebSerial extends EventTarget {
         this.port = null;
         this.reader = null;
         this.writer = null;
+        this.reading = false;
 
         this.connect = this.connect.bind(this);
     }
 
+    handleReceiveBytes(info) {
+        this.bytesReceived += info.detail.byteLength;
+    }
+
+    handleDisconnect() {
+        this.removeEventListener('receive', this.handleReceiveBytes);
+        this.removeEventListener('disconnect', this.handleDisconnect);
+    }
+
     async connect(options) {
         this.openRequested = true;
         this.port = await navigator.serial.requestPort({
@@ -48,6 +57,7 @@ class WebSerial extends EventTarget {
         const connectionInfo = this.port.getInfo();
         this.connectionInfo = connectionInfo;
         this.writer = this.port.writable.getWriter();
+        this.reader = this.port.readable.getReader();
 
         if (connectionInfo && !this.openCanceled) {
             this.connected = true;
@@ -58,9 +68,8 @@ class WebSerial extends EventTarget {
             this.failed = 0;
             this.openRequested = false;
 
-            this.addEventListener("receive", (info) => {
-                this.bytesReceived += info.detail.byteLength;
-            });
+            this.addEventListener("receive", this.handleReceiveBytes);
+            this.addEventListener('disconnect', this.handleDisconnect);
 
             console.log(
                 `${this.logHead} Connection opened with ID: ${connectionInfo.connectionId}, Baud: ${options.baudRate}`,
@@ -73,7 +82,9 @@ class WebSerial extends EventTarget {
             // the stream async iterable interface:
             // https://web.dev/streams/#asynchronous-iteration
 
-            for await (let value of streamAsyncIterable(this.port.readable)) {
+
+            this.reading = true;
+            for await (let value of streamAsyncIterable(this.reader, () => this.reading)) {
                 this.dispatchEvent(
                     new CustomEvent("receive", { detail: value }),
                 );
@@ -108,32 +119,46 @@ class WebSerial extends EventTarget {
 
     async disconnect() {
         this.connected = false;
+        this.transmitting = false;
+        this.reading = false;
+        this.bytesReceived = 0;
+        this.bytesSent = 0;
 
-        if (this.port) {
-            this.transmitting = false;
+        const doCleanup = async () => {
+            if (this.reader) {
+                this.reader.releaseLock();
+                this.reader = null;
+            }
             if (this.writer) {
-                await this.writer.close();
+                await this.writer.releaseLock();
                 this.writer = null;
             }
-            try {
+            if (this.port) {
                 await this.port.close();
                 this.port = null;
+            }
+        };
 
-                console.log(
-                    `${this.logHead}Connection with ID: ${this.connectionId} closed, Sent: ${this.bytesSent} bytes, Received: ${this.bytesReceived} bytes`,
-                );
+        try {
+            await doCleanup();
 
-                this.connectionId = false;
-                this.bitrate = 0;
-                this.dispatchEvent(new CustomEvent("disconnect"));
-            } catch (error) {
-                console.error(error);
-                console.error(
-                    `${this.logHead}Failed to close connection with ID: ${this.connectionId} closed, Sent: ${this.bytesSent} bytes, Received: ${this.bytesReceived} bytes`,
-                );
+            console.log(
+                `${this.logHead}Connection with ID: ${this.connectionId} closed, Sent: ${this.bytesSent} bytes, Received: ${this.bytesReceived} bytes`,
+            );
+
+            this.connectionId = false;
+            this.bitrate = 0;
+            this.dispatchEvent(new CustomEvent("disconnect", { detail: true }));
+        } catch (error) {
+            console.error(error);
+            console.error(
+                `${this.logHead}Failed to close connection with ID: ${this.connectionId} closed, Sent: ${this.bytesSent} bytes, Received: ${this.bytesReceived} bytes`,
+            );
+            this.dispatchEvent(new CustomEvent("disconnect", { detail: false }));
+        } finally {
+            if (this.openCanceled) {
+                this.openCanceled = false;
             }
-        } else {
-            this.openCanceled = true;
         }
     }