Moved platform specific code into its own module

Author: Thomas Preston

codebug_tether/core.py

@@ -1,72 +1,13 @@
 from __future__ import print_function
-import os
-import sys
-import glob
 import time
 import serial
 import struct
-from codebug_tether.i2c import *
-from codebug_tether.serial_channel_device import SerialChannelDevice
-
-
-########################################################################
-# setup DEFAULT_SERIAL_PORT which is different on Windows, MacOS,
-# Raspberry Pi 2 and Raspberry Pi 3
-if sys.platform.startswith('win') or sys.platform.startswith('darwin'):
-    # On Windows or OSX take the first serial port we can find
-    def serial_ports():
-        """ Lists serial port names
-
-            :raises EnvironmentError:
-                On unsupported or unknown platforms
-            :returns:
-                A list of the serial ports available on the system
-        """
-        if sys.platform.startswith('win'):
-            ports = ['COM%s' % (i + 1) for i in range(256)]
-        elif (sys.platform.startswith('linux') or
-                sys.platform.startswith('cygwin')):
-            # this excludes your current terminal "/dev/tty"
-            ports = glob.glob('/dev/tty[A-Za-z0-9]*')
-        elif sys.platform.startswith('darwin'):
-            ports = glob.glob('/dev/tty.*')
-        else:
-            raise EnvironmentError('Unsupported platform')
-
-        result = []
-        for port in ports:
-            try:
-                s = serial.Serial(port)
-                s.close()
-                result.append(port)
-            except (OSError, serial.SerialException):
-                pass
-        return result
-    # use the first one
-    try:
-        DEFAULT_SERIAL_PORT = serial_ports()[0]
-    except IndexError:
-        print('ERROR: Could not find any serial ports.', file=sys.stderr)
-        DEFAULT_SERIAL_PORT = ''
-else:
-    # otherwise assume we're on Raspberry Pi/Linux
-    def get_rpi_revision():
-        """Returns the version number from the revision line."""
-        for line in open("/proc/cpuinfo"):
-            if "Revision" in line:
-                import re
-                return re.sub('Revision\t: ([a-z0-9]+)\n', r'\1', line)
-
-    rpi_revision = get_rpi_revision()
-    if (rpi_revision and
-            (rpi_revision != 'Beta') and
-            (int('0x'+rpi_revision, 16) >= 0xa02082)):
-        # RPi 3 and above
-        DEFAULT_SERIAL_PORT = '/dev/ttyS0'
-    else:
-        # RPi 2 and below
-        DEFAULT_SERIAL_PORT = '/dev/ttyACM0'
-########################################################################
+from .i2c import *
+from .serial_channel_device import SerialChannelDevice
+from .platform import get_platform_serial_port
+
+
+DEFAULT_SERIAL_PORT = get_platform_serial_port()
 
 IO_DIGITAL_OUTPUT = 0
 IO_DIGITAL_INPUT = 1

codebug_tether/platform.py

@@ -0,0 +1,64 @@
+"""Functions for figuring out specific things about the current platform."""
+import re
+import os
+import sys
+import glob
+import serial
+
+
+def get_platform_serial_port():
+    # setup DEFAULT_SERIAL_PORT which is different on Windows, MacOS,
+    # Raspberry Pi 2 and Raspberry Pi 3
+    if sys.platform.startswith('win') or sys.platform.startswith('darwin'):
+        # On Windows or OSX take the first serial port we can find
+        def serial_ports():
+            """ Lists serial port names
+
+                :raises EnvironmentError:
+                    On unsupported or unknown platforms
+                :returns:
+                    A list of the serial ports available on the system
+            """
+            if sys.platform.startswith('win'):
+                ports = ['COM%s' % (i + 1) for i in range(256)]
+            elif (sys.platform.startswith('linux') or
+                    sys.platform.startswith('cygwin')):
+                # this excludes your current terminal "/dev/tty"
+                ports = glob.glob('/dev/tty[A-Za-z0-9]*')
+            elif sys.platform.startswith('darwin'):
+                ports = glob.glob('/dev/tty.*')
+            else:
+                raise EnvironmentError('Unsupported platform')
+
+            result = []
+            for port in ports:
+                try:
+                    s = serial.Serial(port)
+                    s.close()
+                    result.append(port)
+                except (OSError, serial.SerialException):
+                    pass
+            return result
+        # use the first one
+        try:
+            return serial_ports()[0]
+        except IndexError:
+            print('ERROR: Could not find any serial ports.', file=sys.stderr)
+            return ''
+    else:
+        # otherwise assume we're on Raspberry Pi/Linux
+        def get_rpi_revision():
+            """Returns the version number from the revision line."""
+            for line in open("/proc/cpuinfo"):
+                if "Revision" in line:
+                    return re.sub('Revision\t: ([a-z0-9]+)\n', r'\1', line)
+
+        rpi_revision = get_rpi_revision()
+        if (rpi_revision and
+                (rpi_revision != 'Beta') and
+                (int('0x'+rpi_revision, 16) >= 0xa02082)):
+            # RPi 3 and above
+            return '/dev/ttyS0'
+        else:
+            # RPi 2 and below
+            return '/dev/ttyACM0'