WebUSB: Always reset the serial terminal when closed (#312)

Refactor code to close serial terminal into own function.

Now when the serial button is used to close the terminal the
terminal itself is reset as well, as it can be deceiving to have
the old content when the micro:bit serial is reset on reconnects.

It also ensures WebUSB is disconnected before clearing the
dapwrapper in case of an error.

Author: microbit-carlos

python-main.js

@@ -1258,22 +1258,11 @@ function web_editor(config) {
         webusbErrorHandler(error);
     }
 
-    function clearDapWrapper(event) {
-        if(window.dapwrapper || window.previousDapWrapper) {
-            window.dapwrapper = null;
-            window.previousDapWrapper = null;
-        }
-    }
-
     function doConnect(serial) {
         // Change button to connecting
         $("#command-connect").hide();
         $("#command-connecting").show();
         $("#command-disconnect").hide();
-        
-        // Device disconnect listener
-        // Clears dapwrapper
-        navigator.usb.addEventListener('disconnect', clearDapWrapper);
 
         // Show error on WebUSB Disconnect Events
         navigator.usb.addEventListener('disconnect', showDisconnectError);
@@ -1340,19 +1329,16 @@ function web_editor(config) {
         console.log(err);
         console.trace();
 
-        // If there was an error and quick flash is in use, then clear dapwrapper
-        if(usePartialFlashing) {
-            if(window.dapwrapper) {
+        // Disconnect from the microbit
+        doDisconnect().then(function() {
+            // As there has been an error clear the partial flashing DAPWrapper
+            if (window.dapwrapper) {
                 window.dapwrapper = null;
             }
-
-            if(window.previousDapWrapper) {
+            if (window.previousDapWrapper) {
                 window.previousDapWrapper = null;
             }
-        }
-
-        // Disconnect from the microbit
-        doDisconnect();
+        });
 
         var errorType;
         var errorTitle;
@@ -1462,7 +1448,7 @@ function web_editor(config) {
         $('#flashing-overlay').keydown(function(e) {
             if (e.which == 27) {
                 flashErrorClose();
-           }
+            }
         });
 
         // Send event
@@ -1478,22 +1464,13 @@ function web_editor(config) {
     }
 
     function doDisconnect() {
-
-        // Remove disconnect listenr
+        // Remove disconnect listener
         navigator.usb.removeEventListener('disconnect', showDisconnectError);
 
         // Hide serial and disconnect if open
         if ($("#repl").css('display') != 'none') {
-            $("#repl").hide();
-            $("#request-repl").hide();
-            $("#request-serial").hide();
-            $("#editor-container").show();
+            closeSerial();
         }
-        $("#command-serial").attr("title", config["translate"]["static-strings"]["buttons"]["command-serial"]["title"]);
-        $("#command-serial > .roundlabel").text(config["translate"]["static-strings"]["buttons"]["command-serial"]["label"]);
-
-        $("#repl").empty();
-        REPL = null;
 
         // Change button to connect
         $("#command-disconnect").hide();
@@ -1506,22 +1483,23 @@ function web_editor(config) {
 
         var p = Promise.resolve();
 
-        if (usePartialFlashing) {
-            if (window.dapwrapper) {
-                console.log("Disconnecting: Using Quick Flash");
-                p = p.then(function() { window.dapwrapper.daplink.stopSerialRead() } )
-                    .then(function() { window.dapwrapper.disconnectAsync() } );
-            }
+        if (usePartialFlashing && window.dapwrapper) {
+            console.log('Disconnecting: Using Quick Flash');
+            p = p.then(function() { return window.dapwrapper.disconnectAsync() });
         }
-        else {
-            if (window.daplink) {
-                console.log("Disconnecting: Using Full Flash");
-                p = p.then(function() { window.daplink.stopSerialRead() } )
-                    .then(function() { window.daplink.disconnect() } );
-            }
+        else if (window.daplink) {
+            console.log('Disconnecting: Using Full Flash');
+            p = p.then(function() { return window.daplink.disconnect() });
         }
 
-        p.finally(function() {
+        p = p.catch(function() {
+            console.log('Error during disconnection');
+            document.dispatchEvent(new CustomEvent('webusb', { 'detail': {
+                'flash-type': 'webusb',
+                'event-type': 'error',
+                'message': 'error-disconnecting'
+            }}));
+        }).finally(function() {
             console.log('Disconnection Complete');
             document.dispatchEvent(new CustomEvent('webusb', { 'detail': {
                 'flash-type': 'webusb',
@@ -1538,21 +1516,7 @@ function web_editor(config) {
 
         // Hide serial and disconnect if open
         if ($("#repl").css('display') != 'none') {
-            $("#repl").hide();
-            $("#request-repl").hide();
-            $("#request-serial").hide();
-            $("#editor-container").show();
-            $("#command-serial").attr("title", config["translate"]["static-strings"]["buttons"]["command-serial"]["title"]);
-            $("#command-serial > .roundlabel").text(config["translate"]["static-strings"]["buttons"]["command-serial"]["label"]);
-
-            if (usePartialFlashing) {
-                if (window.dapwrapper) {
-                    window.dapwrapper.daplink.stopSerialRead();
-                }
-            }
-            else {
-                window.daplink.stopSerialRead();
-            }
+            closeSerial();
         }
 
         // Get the hex to flash in bytes format, exit if there is an error
@@ -1580,9 +1544,6 @@ function web_editor(config) {
 
         var p = Promise.resolve();
         if (usePartialFlashing) {
-            REPL = null;
-            $("#repl").empty();
-
             p = window.dapwrapper.disconnectAsync()
                 .then(function() {
                     return PartialFlashing.connectDapAsync();
@@ -1640,28 +1601,35 @@ function web_editor(config) {
         });
     }
 
+    function closeSerial(keepSession) {
+        console.log("Closing Serial Terminal");
+        $('#repl').empty();
+        $('#repl').hide();
+        $('#request-repl').hide();
+        $('#request-serial').hide();
+        $('#editor-container').show();
+
+        var serialButton = config['translate']['static-strings']['buttons']['command-serial'];
+        $('#command-serial').attr('title', serialButton['title']);
+        $('#command-serial > .roundlabel').text(serialButton['label']);
+
+        var daplink = usePartialFlashing ? window.dapwrapper.daplink : window.daplink;
+        daplink.stopSerialRead();
+        daplink.removeAllListeners(DAPjs.DAPLink.EVENT_SERIAL_DATA);
+        REPL.uninstallKeyboard();
+        REPL.io.pop();
+        REPL = null;
+    }
+
     function doSerial() {
-        console.log("Setting Up Serial Terminal");
-        // Hide terminal
+        // Hide terminal if it is currently shown
         var serialButton = config["translate"]["static-strings"]["buttons"]["command-serial"];
         if ($("#repl").css('display') != 'none') {
-            $("#repl").hide();
-            $("#request-repl").hide();
-            $("#request-serial").hide();
-            $("#editor-container").show();
-            $("#command-serial").attr("title", serialButton["label"]);
-            $("#command-serial > .roundlabel").text(serialButton["label"]);
-            if (usePartialFlashing) {
-                if (window.dapwrapper) {
-                    window.dapwrapper.daplink.stopSerialRead();
-                }
-            }
-            else {
-                window.daplink.stopSerialRead();
-            }
+            closeSerial();
             return;
         }
 
+        console.log("Setting Up Serial Terminal");
         // Check if we need to connect
         if ($("#command-connect").is(":visible")){
             doConnect(true);
@@ -1757,8 +1725,8 @@ function web_editor(config) {
         $(overlayContainer).keydown(function(e) {
             if (e.which == 27) {
                 modalMsgClose();
-           }
-       });
+            }
+        });
     }
 
     function formatMenuContainer(parentButtonId, containerId) {