Display an error message when the microcontroller is disconnected

This way the debugger does not just get stuck when that happens, it cleanly stops.

Author: MaartenS11

src/main/kotlin/be/ugent/topl/mio/debugger/Debugger.kt

@@ -24,18 +24,30 @@ open class Debugger(private val connection: Connection, start: Boolean = true, p
             }
         }
     }
+    val errorHandlers = mutableListOf<(String) -> Unit>()
     private val readThread  = thread(start) {
         while (!Thread.currentThread().isInterrupted) {
-            while (connection.bytesAvailable() == 0) {
+            var available = connection.bytesAvailable()
+            while (available == 0) {
                 try {
                     Thread.sleep(10)
                 } catch (_: InterruptedException) {
                     Thread.currentThread().interrupt()
                     break
                 }
+                available = connection.bytesAvailable()
+            }
+            if (available == -1) {
+                println("WARDuino disconnected")
+                thread {
+                    for (el in errorHandlers) {
+                        el.invoke("WARDuino disconnected")
+                    }
+                }
+                return@thread
             }
 
-            val readBuffer = ByteArray(connection.bytesAvailable())
+            val readBuffer = ByteArray(available)
             connection.read(readBuffer)
             messageQueue.push(String(readBuffer), true)
 

src/main/kotlin/be/ugent/topl/mio/ui/InteractiveDebugger.kt

@@ -45,7 +45,7 @@ class InteractiveDebugger(
     private val config: DebuggerConfig
 ) : JFrame("WARDuino Debugger") {
     private val binaryInfo = getBinaryInfo(config.wdcliPath, File(wasmFile).absolutePath).getOrElse {
-        JOptionPane.showMessageDialog(this, it.message, "Error obtaining binary info", JOptionPane.ERROR_MESSAGE)
+        JOptionPane.showMessageDialog(this, it.message, "Error obtaining binary info", ERROR_MESSAGE)
         exitProcess(1)
     }
     private val debugger = MultiverseDebugger(
@@ -56,7 +56,12 @@ class InteractiveDebugger(
         this::onGraphUpdate,
         this::onMockingUpdate,
         this::onHitBreakpoint
-    )
+    ).apply {
+        errorHandlers.add {
+            JOptionPane.showMessageDialog(this@InteractiveDebugger, it, "An error occurred", ERROR_MESSAGE)
+            exitProcess(1)
+        }
+    }
     private val pauseButton = JButton().apply {
         toolTipText = "Pause/Continue"
     }