Merge pull request #45 from mbuesch/portexception

Handle port errors gracefully and print proper error messages

Author: mithro

programmer/tinyprog/__init__.py

@@ -68,11 +68,14 @@ def get_ports(device_id):
         import usb
         vid, pid = [int(x, 16) for x in device_id.split(":")]
 
-        ports += [
-            UsbPort(d)
-            for d in usb.core.find(idVendor=vid, idProduct=pid, find_all=True)
-            if not d.is_kernel_driver_active(1)
-        ]
+        try:
+            ports += [
+                UsbPort(usb, d)
+                for d in usb.core.find(idVendor=vid, idProduct=pid, find_all=True)
+                if not d.is_kernel_driver_active(1)
+            ]
+        except usb.core.USBError as e:
+            raise PortError("Failed to open USB:\n%s" % str(e))
 
     # MacOS is not playing nicely with the serial drivers for the bootloader
     if platform.system() != "Darwin" or use_pyserial:
@@ -84,6 +87,9 @@ def get_ports(device_id):
     return ports
 
 
+class PortError(Exception):
+    pass
+
 class SerialPort(object):
     def __init__(self, port_name):
         self.port_name = port_name
@@ -93,24 +99,39 @@ def __str__(self):
         return self.port_name
 
     def __enter__(self):
-        self.ser = serial.Serial(
-            self.port_name, timeout=1.0, writeTimeout=1.0).__enter__()
+        try:
+            self.ser = serial.Serial(
+                self.port_name, timeout=1.0, writeTimeout=1.0).__enter__()
+        except serial.SerialException as e:
+            raise PortError("Failed to open serial port:\n%s" % str(e))
 
     def __exit__(self, exc_type, exc_val, exc_tb):
-        self.ser.__exit__(exc_type, exc_val, exc_tb)
+        try:
+            self.ser.__exit__(exc_type, exc_val, exc_tb)
+        except serial.SerialException as e:
+            raise PortError("Failed to close serial port:\n%s" % str(e))
 
     def write(self, data):
-        self.ser.write(data)
+        try:
+            self.ser.write(data)
+        except serial.SerialException as e:
+            raise PortError("Failed to write to serial port:\n%s" % str(e))
 
     def flush(self):
-        self.ser.flush()
+        try:
+            self.ser.flush()
+        except serial.SerialException as e:
+            raise PortError("Failed to flush serial port:\n%s" % str(e))
 
     def read(self, length):
-        return self.ser.read(length)
-
+        try:
+            return self.ser.read(length)
+        except serial.SerialException as e:
+            raise PortError("Failed to read from serial port:\n%s" % str(e))
 
 class UsbPort(object):
-    def __init__(self, device):
+    def __init__(self, usb, device):
+        self.usb = usb
         self.device = device
         usb_interface = device.configurations()[0].interfaces()[1]
         self.OUT = usb_interface.endpoints()[0]
@@ -126,19 +147,24 @@ def __exit__(self, exc_type, exc_val, exc_tb):
         pass
 
     def write(self, data):
-        self.OUT.write(data)
+        try:
+            self.OUT.write(data)
+        except self.usb.core.USBError as e:
+            raise PortError("Failed to write to USB:\n%s" % str(e))
 
     def flush(self):
         # i don't think there's a comparable function on pyusb endpoints
         pass
 
     def read(self, length):
-        if length > 0:
-            data = self.IN.read(length)
-            return bytearray(data)
-        else:
-            return ""
-
+        try:
+            if length > 0:
+                data = self.IN.read(length)
+                return bytearray(data)
+            else:
+                return ""
+        except self.usb.core.USBError as e:
+            raise PortError("Failed to read from USB:\n%s" % str(e))
 
 def _mirror_byte(b):
     return bit_reverse_table[to_int(b)]