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"""
This module contains the base device type for the `AlarmDecoder`_ (AD2) family.
.. _AlarmDecoder: http://www.alarmdecoder.com
.. moduleauthor:: Scott Petersen <scott@nutech.com>
"""
import threading
from ..util import CommError, TimeoutError, InvalidMessageError
from ..event import event
try:
from OpenSSL import SSL, crypto
have_openssl = True
except ImportError:
class SSL:
class Error(BaseException):
pass
class WantReadError(BaseException):
pass
class SysCallError(BaseException):
pass
have_openssl = False
class Device(object):
"""
Base class for all `AlarmDecoder`_ (AD2) device types.
"""
# Generic device events
on_open = event.Event("This event is called when the device has been opened.\n\n**Callback definition:** *def callback(device)*")
on_close = event.Event("This event is called when the device has been closed.\n\n**Callback definition:** def callback(device)*")
on_read = event.Event("This event is called when a line has been read from the device.\n\n**Callback definition:** def callback(device, data)*")
on_write = event.Event("This event is called when data has been written to the device.\n\n**Callback definition:** def callback(device, data)*")
def __init__(self):
"""
Constructor
"""
self._id = ''
self._buffer = b''
self._device = None
self._running = False
self._read_thread = None
def __enter__(self):
"""
Support for context manager __enter__.
"""
return self
def __exit__(self, exc_type, exc_value, traceback):
"""
Support for context manager __exit__.
"""
self.close()
return False
@property
def id(self):
"""
Retrieve the device ID.
:returns: identification string for the device
"""
return self._id
@id.setter
def id(self, value):
"""
Sets the device ID.
:param value: device identification string
:type value: string
"""
self._id = value
def is_reader_alive(self):
"""
Indicates whether or not the reader thread is alive.
:returns: whether or not the reader thread is alive
"""
return self._read_thread.is_alive()
def stop_reader(self):
"""
Stops the reader thread.
"""
self._read_thread.stop()
def close(self):
"""
Closes the device.
"""
try:
self._running = False
self._read_thread.stop()
self._device.close()
except Exception:
pass
self.on_close()
class ReadThread(threading.Thread):
"""
Reader thread which processes messages from the device.
"""
READ_TIMEOUT = 10
"""Timeout for the reader thread."""
def __init__(self, device):
"""
Constructor
:param device: device used by the reader thread
:type device: :py:class:`~alarmdecoder.devices.Device`
"""
threading.Thread.__init__(self)
self._device = device
self._running = False
def stop(self):
"""
Stops the running thread.
"""
self._running = False
def run(self):
"""
The actual read process.
"""
self._running = True
while self._running:
try:
self._device.read_line(timeout=self.READ_TIMEOUT)
except TimeoutError:
pass
except InvalidMessageError:
pass
except SSL.WantReadError:
pass
except CommError as err:
self._device.close()
except Exception as err:
self._device.close()
self._running = False
raise
|
