pbio/drv/bluetooth: Raise on sending app data when disconnected.

We wouldn't want to wait forever if there is no connection. With stdout, the output is just ignored, but here it makes sense to raise.

Author: laurensvalk

lib/pbio/drv/bluetooth/bluetooth.c

@@ -107,14 +107,18 @@ bool pbdrv_bluetooth_tx_is_idle(void) {
 }
 
 /**
- * Buffer for generic notification, but not buffered or schedules.
+ * Buffer for generic awaitable notification.
  */
 static uint8_t user_notification_send_buf[PBDRV_BLUETOOTH_MAX_CHAR_SIZE];
 static size_t user_notification_size;
 
 pbio_error_t pbdrv_bluetooth_send_event_notification(pbio_os_state_t *state, pbio_pybricks_event_t event_type, const uint8_t *data, size_t size) {
     PBIO_OS_ASYNC_BEGIN(state);
 
+    if (!pbdrv_bluetooth_is_connected(PBDRV_BLUETOOTH_CONNECTION_PYBRICKS)) {
+        return PBIO_ERROR_INVALID_OP;
+    }
+
     if (size + 1 > PBIO_ARRAY_SIZE(user_notification_send_buf)) {
         return PBIO_ERROR_INVALID_ARG;
     }
@@ -130,7 +134,8 @@ pbio_error_t pbdrv_bluetooth_send_event_notification(pbio_os_state_t *state, pbi
     memcpy(&user_notification_send_buf[1], data, size);
     pbio_os_request_poll();
 
-    // Await until main process has finished sending user data.
+    // Await until main process has finished sending user data. If it
+    // disconnected while sending, this completes as well.
     PBIO_OS_AWAIT_WHILE(state, user_notification_size);
 
     PBIO_OS_ASYNC_END(PBIO_SUCCESS);

lib/pbio/include/pbdrv/bluetooth.h

@@ -328,6 +328,7 @@ bool pbdrv_bluetooth_tx_is_idle(void);
  * @param [in] data     Data to send.
  * @param [in] size     Data size, not counting event type byte.
  * @return              ::PBIO_SUCCESS on completion.
+ *                      ::PBIO_ERROR_INVALID_OP if there is no connection.
  *                      ::PBIO_ERROR_AGAIN while awaiting.
  *                      ::PBIO_ERROR_BUSY if this operation is already ongoing.
  *                      ::PBIO_ERROR_INVALID_ARG if @p size is too large.

lib/pbio/sys/host.c

@@ -218,7 +218,7 @@ bool pbsys_host_tx_is_idle(void) {
  * @param size        [in]  The size of the data to transmit.
  *                          contains the number of bytes actually processed.
  * @return                  ::PBIO_ERROR_AGAIN while the operation is in progress.
- *                          ::PBIO_ERROR_NODEV if there is no connection to send it to.
+ *                          ::PBIO_ERROR_INVALID_OP if there is no connection to send it to.
  *                          ::PBIO_ERROR_BUSY if another transfer is already queued or in progress.
  *                          ::PBIO_SUCCESS on completion.
  */