class Protocol(object):
_STATE_IDLE = 0
_STATE_HEADER_MAGIC_0 = 1
_STATE_HEADER_MAGIC_1 = 2
_STATE_HEADER_MAGIC_2 = 3
_STATE_HEADER_MAGIC_3 = 4
_STATE_HEADER = 5
_STATE_PAYLOAD = 6
def __init__(self):
self.state = Protocol._STATE_IDLE
self.headerBuf = None
self.header = None
self.msg = None
self.bufSrc = None
self.offSrc = 0
self.lenSrc = 0
self._reset()
def decode(self, buf, off):
rxMsg = None
# If idle start a new parsing
if self.state == Protocol._STATE_IDLE:
self.state = Protocol._STATE_HEADER_MAGIC_0
# Setup source buffer
self.bufSrc = buf
self.offSrc = off
self.lenSrc = len(buf) - off
while self.lenSrc > 0 and self.state != Protocol._STATE_IDLE:
if self.state == Protocol._STATE_HEADER_MAGIC_0:
self._reset()
self.state = Protocol._STATE_HEADER_MAGIC_0
self._copyOne(self.headerBuf)
self._checkMagic(0, POMP_MAGIC_0, Protocol._STATE_HEADER_MAGIC_1)
elif self.state == Protocol._STATE_HEADER_MAGIC_1:
self._copyOne(self.headerBuf)
self._checkMagic(1, POMP_MAGIC_1, Protocol._STATE_HEADER_MAGIC_2)
elif self.state == Protocol._STATE_HEADER_MAGIC_2:
self._copyOne(self.headerBuf)
self._checkMagic(2, POMP_MAGIC_2, Protocol._STATE_HEADER_MAGIC_3)
elif self.state == Protocol._STATE_HEADER_MAGIC_3:
self._copyOne(self.headerBuf)
self._checkMagic(3, POMP_MAGIC_3, Protocol._STATE_HEADER)
elif self.state == Protocol._STATE_HEADER:
self._copy(self.headerBuf, HEADER_SIZE)
if len(self.headerBuf) == HEADER_SIZE:
self._decodeHeader()
elif self.state == Protocol._STATE_PAYLOAD:
self._copy(self.msg.buf, self.header.size)
else:
assert False
# Check end of payload
if (self.state == Protocol._STATE_PAYLOAD
and len(self.msg.buf) == self.header.size):
# Give ownership of message to caller
self.msg.setFinished()
rxMsg = self.msg
self.msg = None
self.state = Protocol._STATE_IDLE
return (self.offSrc, rxMsg)
def _reset(self):
self.state = Protocol._STATE_IDLE
self.headerBuf = Buffer()
self.header = None
self.msg = None
def _checkMagic(self, idx, val, state):
if isinstance(self.headerBuf.getData(), str):
magic = ord(self.headerBuf.getData()[idx])
else:
magic = self.headerBuf.getData()[idx]
if magic != val:
_log.warning("Bad header magic %d: 0x%02x(0x%02x)", idx, magic, val)
self.state = Protocol._STATE_HEADER_MAGIC_0
else:
self.state = state
def _copyOne(self, bufDst):
bufDst.write(self.bufSrc[self.offSrc:self.offSrc+1])
self.offSrc += 1
self.lenSrc -= 1
def _copy(self, bufDst, sizeDst):
cpyLen = min(self.lenSrc, sizeDst - len(bufDst))
bufDst.write(self.bufSrc[self.offSrc:self.offSrc+cpyLen])
self.offSrc += cpyLen
self.lenSrc -= cpyLen
def _decodeHeader(self):
try:
# Decode header fields
self.headerBuf.rewind()
magic = self.headerBuf.readInt()
msgid = self.headerBuf.readInt()
size = self.headerBuf.readInt()
self.header = Header(magic, msgid, size)
# Check header and setup payload decoding */
if self.header.size < HEADER_SIZE:
_log.warning("Bad header size: %d", self.header.size)
self.state = Protocol._STATE_HEADER_MAGIC_0
else:
self._allocMsg(self.header.msgid, self.header.size)
self.msg.buf.write(self.headerBuf.getData())
self.state = Protocol._STATE_PAYLOAD
except struct.error as ex:
_log.error(ex)
self.state = Protocol._STATE_HEADER_MAGIC_0
def _allocMsg(self, msgid, size):
from pomp.message import Message
self.msg = Message()
self.msg.init(msgid)
def _reset(self):
self.state = Protocol._STATE_IDLE
self.headerBuf = Buffer()
self.header = None
self.msg = None
def init(self, msgid):
self.msgid = msgid
self.finished = False
self.buf = Buffer()
class Message(object):
def __init__(self):
self.msgid = 0 # Id of message
self.finished = False # Header is filled
self.buf = None # Buffer with data
def init(self, msgid):
self.msgid = msgid
self.finished = False
self.buf = Buffer()
def finish(self):
# Make sure position is at least after header
if self.buf.getPos() < protocol.HEADER_SIZE:
self.buf.skip(protocol.HEADER_SIZE - self.buf.getPos())
# Write header
self.buf.rewind()
self.buf.writeInt(protocol.POMP_MAGIC)
self.buf.writeInt(self.msgid)
self.buf.writeInt(len(self.buf))
# Make message read-only
self.finished = True
self.buf.setReadOnly(True)
def setFinished(self):
self.finished = True
self.buf.setReadOnly(True)
def clear(self):
self.msgid = 0
self.finished = False
self.buf = None
def write(self, msgid, fmt, *args):
self.init(msgid)
enc = Encoder()
enc.init(self)
enc.write(fmt, *args)
enc.clear()
self.finish()
def read(self, fmt):
dec = Decoder()
dec.init(self)
res = dec.read(fmt)
dec.clear()
return res
def dump(self):
dec = Decoder()
dec.init(self)
res = dec.dump()
dec.clear()
return res
def init(self, msgid):
self.msgid = msgid
self.finished = False
self.buf = Buffer()
class Message(object):
def __init__(self):
self.msgid = 0 # Id of message
self.finished = False # Header is filled
self.buf = None # Buffer with data
def init(self, msgid):
self.msgid = msgid
self.finished = False
self.buf = Buffer()
def finish(self):
# Make sure position is at least after header
if self.buf.getPos() < protocol.HEADER_SIZE:
self.buf.skip(protocol.HEADER_SIZE - self.buf.getPos())
# Write header
self.buf.rewind()
self.buf.writeInt(protocol.POMP_MAGIC)
self.buf.writeInt(self.msgid)
self.buf.writeInt(len(self.buf))
# Make message read-only
self.finished = True
self.buf.setReadOnly(True)
def setFinished(self):
self.finished = True
self.buf.setReadOnly(True)
def clear(self):
self.msgid = 0
self.finished = False
self.buf = None
def write(self, msgid, fmt, *args):
self.init(msgid)
enc = Encoder()
enc.init(self)
enc.write(fmt, *args)
enc.clear()
self.finish()
def read(self, fmt):
dec = Decoder()
dec.init(self)
res = dec.read(fmt)
dec.clear()
return res
def dump(self):
dec = Decoder()
dec.init(self)
res = dec.dump()
dec.clear()
return res
