Add Serial.isConnected to check if Bluetooth/USB/etc actually connected

ChangeLog

@@ -58,6 +58,7 @@
             Fix UtilTimer timings when new task added infront of existing tasks (fix #2575)
             Graphics: Fix issue where drawLine for 2px horizontal lines only drew a 1px dot
             nRF52: Add E.setComparator to enable interrupts from LPCOMP
+            Add Serial.isConnected to check if Bluetooth/USB/etc actually connected
 
      2v24 : Bangle.js2: Add 'Bangle.touchRd()', 'Bangle.touchWr()'
             Bangle.js2: After Bangle.showTestScreen, put Bangle.js into a hard off state (not soft off)

libs/network/telnet/jswrap_telnet.c

@@ -62,6 +62,8 @@ typedef struct {
   uint16_t     txBufLen;         ///< number of chars in tx buffer
 } TelnetServer;
 
+/// Set if Telnet overflow
+static bool ovf;
 static TelnetServer tnSrv;        ///< the telnet server, only one right now
 static uint8_t      tnSrvMode;    ///< current mode for the telnet server
 
@@ -174,6 +176,11 @@ bool jswrap_telnet_idle(void) {
   return active;
 }
 
+/* Is something connected to Telnet? */
+bool jswrap_telnet_isConnected() {
+  return tnSrv.cliSock>0;
+}
+
 //===== Internal functions
 
 // Start the listening socket for the telnet console server.
@@ -258,8 +265,6 @@ bool telnetSendBuf(JsNetwork *net) {
   return sent != 0;
 }
 
-static bool ovf;
-
 void telnetSendChar(char ch) {
   if (tnSrv.sock == 0 || tnSrv.cliSock == 0) return;
   if (tnSrv.txBufLen >= TX_CHUNK) {

libs/network/telnet/jswrap_telnet.h

@@ -25,4 +25,8 @@ void jswrap_telnet_kill(void);
 // was done.
 bool jswrap_telnet_idle(void);
 
+/* Is something connected to Telnet? */
+bool jswrap_telnet_isConnected();
+
+
 #endif

src/jswrap_serial.c

@@ -17,6 +17,12 @@
 #include "jsdevices.h"
 #include "jsinteractive.h"
 #include "jsserial.h"
+#ifdef USE_TELNET
+#include "jswrap_telnet.h"
+#endif
+#ifdef BLUETOOTH
+#include "jswrap_bluetooth.h"
+#endif
 
 /*JSON{
   "type" : "class",
@@ -556,4 +562,37 @@ void jswrap_serial_flush(JsVar *parent) {
   IOEventFlags device = jsiGetDeviceFromClass(parent);
   if (device == EV_NONE) return;
   jshTransmitFlushDevice(device);
+}
+
+/*JSON{
+  "type" : "method",
+  "class" : "Serial",
+  "name" : "isConnected",
+  "generate" : "jswrap_serial_isConnected",
+  "return" : ["bool","`true` if connected/initialised, false otherwise"]
+}
+(Added 2v25) Is the given Serial device connected?
+
+* USB/Bluetooth/Telnet/etc: Is this connected?
+* Serial1/etc: Has the device been initialised?
+* LoopbackA/LoopbackB/Terminal: always return true
+ */
+bool jswrap_serial_isConnected(JsVar *parent) {
+  IOEventFlags device = jsiGetDeviceFromClass(parent);
+  if (device==EV_LOOPBACKA || device==EV_LOOPBACKB) return true;
+#ifdef USE_TERMINAL
+  if (device == EV_TERMINAL) return true;
+#endif
+#ifdef USE_TELNET
+  if (device == EV_TELNET) return jswrap_telnet_isConnected();
+#endif
+#ifdef USB
+  if (device == EV_USBSERIAL) return jshIsUSBSERIALConnected();
+#endif
+#ifdef BLUETOOTH
+  if (device == EV_BLUETOOTH) return jsble_has_peripheral_connection();
+#endif
+  if (DEVICE_IS_USART(device))
+    return jshIsDeviceInitialised(device);
+  return false;
 }

src/jswrap_serial.h

@@ -26,5 +26,6 @@ void jswrap_serial_println(JsVar *parent, JsVar *str);
 void jswrap_serial_write(JsVar *parent, JsVar *data);
 void jswrap_serial_inject(JsVar *parent, JsVar *args);
 void jswrap_serial_flush(JsVar *parent);
+bool jswrap_serial_isConnected(JsVar *parent);
 
 #endif // JSWRAP_SERIAL_H_