throw a specific exception for serial port errors

3 files changed, 31 insertions, 12 deletions

diff --git a/dexcom_reader/constants.py b/dexcom_reader/constants.py
index 628d325..08c62ec 100644
--- a/dexcom_reader/constants.py
+++ b/dexcom_reader/constants.py
@@ -8,6 +8,8 @@ class Error(Exception):
 class CrcError(Error):
   """Failed to CRC properly."""
 
+class SerialPortError(Error):
+  """Error communicating with Dexcom receiver."""
 
 DEXCOM_G4_USB_VENDOR = 0x22a3
 DEXCOM_G4_USB_PRODUCT = 0x0047
diff --git a/dexcom_reader/dexcom_dumper.py b/dexcom_reader/dexcom_dumper.py
index 0a2d8ee..18724ac 100755
--- a/dexcom_reader/dexcom_dumper.py
+++ b/dexcom_reader/dexcom_dumper.py
@@ -166,12 +166,9 @@ def poll():
                 try:
                         poll_remote() if HOST else poll_stdout()
 
-                except ValueError as v:
-                        if (v.args[0] == 'Attempting to use a port that is not open'):
-                                connected(False)
-                                dexcom_reconnect()
-                        else:
-                                print_verbose('Caught error: %s' % v.args[0])
+                except constants.SerialPortError:
+                        connected(False)
+                        dexcom_reconnect()
                         sleep_verbose(10)
                 except KeyboardInterrupt:
                         print_verbose('Exiting.')
diff --git a/dexcom_reader/readdata.py b/dexcom_reader/readdata.py
index e589b1a..84c2356 100644
--- a/dexcom_reader/readdata.py
+++ b/dexcom_reader/readdata.py
@@ -11,7 +11,7 @@ import re
 import util
 import xml.etree.ElementTree as ET
 import platform
-
+import termios
 
 class ReadPacket(object):
   def __init__(self, command, data):
@@ -74,10 +74,20 @@ class Dexcom(object):
     return self._port
 
   def write(self, *args, **kwargs):
-    return self.port.write(*args, **kwargs)
+    try:
+      return self.port.write(*args, **kwargs)
+    except ValueError:
+      raise constants.SerialPortError
+    except termios.error:
+      raise constants.SerialPortError
 
   def read(self, *args, **kwargs):
-    return self.port.read(*args, **kwargs)
+    try:
+      return self.port.read(*args, **kwargs)
+    except ValueError:
+      raise constants.SerialPortError
+    except termios.error:
+      raise constants.SerialPortError
 
   def readpacket(self, timeout=None):
     total_read = 4
@@ -218,11 +228,21 @@ class Dexcom(object):
     return ET.fromstring(data)
 
   def flush(self):
-    self.port.flush()
+    try:
+      self.port.flush()
+    except ValueError:
+      raise constants.SerialPortError
+    except termios.error:
+      raise constants.SerialPortError
 
   def clear(self):
-    self.port.flushInput()
-    self.port.flushOutput()
+    try:
+      self.port.flushInput()
+      self.port.flushOutput()
+    except ValueError:
+      raise constants.SerialPortError
+    except termios.error:
+      raise constants.SerialPortError
 
   def GetFirmwareHeader(self):
     i = self.GenericReadCommand(constants.READ_FIRMWARE_HEADER)