class Entry(object):
"""
Represents an Entry in the NetworkTable.
"""
NEXT_ID = 0
def __init__(self, name, value, manager, auto_id=True):
self.MANAGER = manager
self.name = name
# The entries actual value, should be accessed as Entry().value.
self._value = value
self.type = get_type(value)
# The next ID if it's a server, otherwise an UNDEFINED_ID.
if self.MANAGER.is_server and auto_id:
self.id = Entry.NEXT_ID
Entry.NEXT_ID += 1
else:
self.id = UNDEFINED_ID
# An indicator of whether or not this entry needs to be sent
# over the network.
self.dirty = False
self.sequence_number = SequenceNumber()
# A socket not to send it over.
self.ignore = None
def copy(self):
"Create a shallow copy of the entry."
copy = Entry(self.name, self.value, self.MANAGER, False)
copy.__dict__ = self.__dict__
return copy
def _get_value(self):
"Getter for value."
return self._value
def _set_value(self, value):
"Setter for value, auto dirties and queques the entry."
self._value = value
self.sequence_number.increment()
if not(self.dirty):
self.MANAGER.add_dirty_entry(self)
if self.id != UNDEFINED_ID:
self.dirty = True
self.ignore = None
# With a property calling Entry().value calls the getter and
# Entry().value = val calls the setter.
value = property(_get_value, _set_value)
def __init__(self, name, value, auto_id=True):
self.name = name
# The entries actual value, should be accessed as Entry().value.
self._value = value
self.type = get_type(value)
# The next ID if it's a server, otherwise an UNDEFINED_ID.
if IS_SERVER and auto_id:
self.id = Entry.NEXT_ID
Entry.NEXT_ID += 1
else:
self.id = UNDEFINED_ID
# An indicator of whether or not this entry needs to be sent
# over the network.
self.dirty = False
self.sequence_number = SequenceNumber()
# A socket not to send it over.
self.ignore = None
def __init__(self, **options):
self._set_options(**options)
self._seq_number = SequenceNumber(*self._sequenceRange)
class Protocol(object):
_seq_number = None
_default_opts = {}
def _set_options(self, **options):
opts = self._default_opts.copy()
opts.update(options)
# FIXME: This method needs revision
self._commandRange = options.get('commandRange', (0x20, 0x7f))
self._sequenceRange = options.get('sequenceRange', (0x20, 0x7f))
def __init__(self, **options):
self._set_options(**options)
self._seq_number = SequenceNumber(*self._sequenceRange)
def build_message(self, command, *params):
"""
Build a message from a command and parameters
with STX, ETX and BCC marks and next Sequence Number.
Ready for send as request to the device.
"""
seq = self._seq_number.next()
return self.build_message_with_seq(command, seq, *params)
def build_message_with_seq(self, command, seq, *params):
"""
Build a message from a command, sequence number and parameters
see build_message() for more detail. This method is suitable when
we need to set an explicit sequence number like when we are implementing
an emulation device.
"""
if isinstance(seq, int):
seq = chr(seq)
if not self._check_sequence_range(seq):
raise OutOfRangeError("seq %r out of valid range (%x, %x)" % \
(seq, self._sequenceRange[0], self._sequenceRange[1]))
if not self._check_command_range(seq):
raise OutOfRangeError("Command %r out of valid range (%x, %x)" % \
(command, self._commandRange[0], self._commandRange[1]))
params = self.build_params(params)
msg = symbols.STX + seq + command + params + symbols.ETX
bcc = self._makeBCC(msg)
return msg + bcc
def parse_message(self, message, check_sequence_number=True):
if not self._checkBCC(message):
received = message[-4:]
expected = self._makeBCC(message[:-4])
raise BadBlockCheckCharacterError("received: %r, expected: %r in message: %r " % \
(received, expected, message))
# Cut off bcc
message = orig_message = message[:-4]
head, stx, message = message.partition(symbols.STX)
if head:
raise MalformedMessageError("%r isn't the first character in %r" % (stx, orig_message))
message, etx, tail = message.rpartition(symbols.ETX)
if tail:
raise MalformedMessageError("%r isn't the last character in %r" % (etx, orig_message))
seq_no = message[0]
if check_sequence_number:
if seq_no != repr(self._seq_number):
raise ValueError("Inconsistent sequence number %r, we are waiting for %r" % \
(ord(seq_no), ord(repr(self._seq_number))))
seq_no = ''
command = message[1]
if not self._check_command_range(command):
raise ValueError("Command %r out of valid range" % command)
params = self.parse_params(message[2:])
if seq_no:
return [ord(seq_no), command] + params
else:
return [command] + params
def build_params(self, params):
"Build a stream with parameters separated by self.FS (FieldSeparator)"
if not params:
return ""
return symbols.FS + symbols.FS.join(params)
def parse_params(self, s):
"Return a list of parameters"
if not s:
return []
orig_s = s
head, fs, s = s.partition(symbols.FS)
if head:
raise MalformedMessageError("%r isn't the first character in parameters substring %r" % \
(fs, orig_s))
return s.split(symbols.FS)
def _makeBCC(self, s):
"Return Block Check Character of message"
return "%.4X" % sum([ord(c) for c in s])
def _checkBCC(self, message):
"Return True if Block Check Character its OK, False otherwise"
return self._makeBCC(message[:-4]) == message[-4:].upper()
def _check_command_range(self, command):
assert len(command) == 1, "Command isn't a character"
return self._commandRange[0] < ord(command) < self._commandRange[1]
def _check_sequence_range(self, sequence):
assert len(sequence) == 1, "Sequence isn't a character"
return self._sequenceRange[0] < ord(sequence) < self._sequenceRange[1]
