Reference client for Bitmessage: a P2P encrypted decentralised communication protocol:
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"""
src/network/advanceddispatcher.py
=================================
"""
# pylint: disable=attribute-defined-outside-init
import socket
import threading
import time
import network.asyncore_pollchoose as asyncore
import state
from threads import BusyError, nonBlocking
class ProcessingError(Exception):
"""General class for protocol parser exception, use as a base for others."""
pass
class UnknownStateError(ProcessingError):
"""Parser points to an unknown (unimplemented) state."""
pass
class AdvancedDispatcher(asyncore.dispatcher):
"""Improved version of asyncore dispatcher, with buffers and protocol state."""
# pylint: disable=too-many-instance-attributes
_buf_len = 131072 # 128kB
def __init__(self, sock=None):
if not hasattr(self, '_map'):
asyncore.dispatcher.__init__(self, sock)
self.read_buf = bytearray()
self.write_buf = bytearray()
self.state = "init"
self.lastTx = time.time()
self.sentBytes = 0
self.receivedBytes = 0
self.expectBytes = 0
self.readLock = threading.RLock()
self.writeLock = threading.RLock()
self.processingLock = threading.RLock()
def append_write_buf(self, data):
"""Append binary data to the end of stream write buffer."""
if data:
if isinstance(data, list):
with self.writeLock:
for chunk in data:
self.write_buf.extend(chunk)
else:
with self.writeLock:
self.write_buf.extend(data)
def slice_write_buf(self, length=0):
"""Cut the beginning of the stream write buffer."""
if length > 0:
with self.writeLock:
if length >= len(self.write_buf):
del self.write_buf[:]
else:
del self.write_buf[0:length]
def slice_read_buf(self, length=0):
"""Cut the beginning of the stream read buffer."""
if length > 0:
with self.readLock:
if length >= len(self.read_buf):
del self.read_buf[:]
else:
del self.read_buf[0:length]
def process(self):
"""Process (parse) data that's in the buffer, as long as there is enough data and the connection is open."""
while self.connected and not state.shutdown:
try:
with nonBlocking(self.processingLock):
if not self.connected or state.shutdown:
break
if len(self.read_buf) < self.expectBytes:
return False
try:
cmd = getattr(self, "state_" + str(self.state))
except AttributeError:
self.logger.error(
'Unknown state %s', self.state, exc_info=True)
raise UnknownStateError(self.state)
if not cmd():
break
except BusyError:
return False
return False
def set_state(self, state_str, length=0, expectBytes=0):
"""Set the next processing state."""
self.expectBytes = expectBytes
self.slice_read_buf(length)
self.state = state_str
def writable(self):
"""Is data from the write buffer ready to be sent to the network?"""
self.uploadChunk = AdvancedDispatcher._buf_len
if asyncore.maxUploadRate > 0:
self.uploadChunk = int(asyncore.uploadBucket)
self.uploadChunk = min(self.uploadChunk, len(self.write_buf))
return asyncore.dispatcher.writable(self) and \
(self.connecting or (self.connected and self.uploadChunk > 0))
def readable(self):
"""Is the read buffer ready to accept data from the network?"""
self.downloadChunk = AdvancedDispatcher._buf_len
if asyncore.maxDownloadRate > 0:
self.downloadChunk = int(asyncore.downloadBucket)
try:
if self.expectBytes > 0 and not self.fullyEstablished:
self.downloadChunk = min(self.downloadChunk, self.expectBytes - len(self.read_buf))
if self.downloadChunk < 0:
self.downloadChunk = 0
except AttributeError:
pass
return asyncore.dispatcher.readable(self) and \
(self.connecting or self.accepting or (self.connected and self.downloadChunk > 0))
def handle_read(self):
"""Append incoming data to the read buffer."""
self.lastTx = time.time()
newData = self.recv(self.downloadChunk)
self.receivedBytes += len(newData)
asyncore.update_received(len(newData))
with self.readLock:
self.read_buf.extend(newData)
def handle_write(self):
"""Send outgoing data from write buffer."""
self.lastTx = time.time()
written = self.send(self.write_buf[0:self.uploadChunk])
asyncore.update_sent(written)
self.sentBytes += written
self.slice_write_buf(written)
def handle_connect_event(self):
"""Callback for connection established event."""
try:
asyncore.dispatcher.handle_connect_event(self)
except socket.error as e:
if e.args[0] not in asyncore._DISCONNECTED: # pylint: disable=protected-access
raise
def handle_connect(self):
"""Method for handling connection established implementations."""
self.lastTx = time.time()
def state_close(self):
"""Signal to the processing loop to end."""
# pylint: disable=no-self-use
return False
def handle_close(self):
"""Callback for connection being closed, but can also be called directly when you want connection to close."""
with self.readLock:
self.read_buf = bytearray()
with self.writeLock:
self.write_buf = bytearray()
self.set_state("close")
self.close()