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#!/usr/bin/env python
# Copyright JS Foundation and other contributors, http://js.foundation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import struct
MAX_BUFFER_SIZE = 256
class RawPacket(object):
""" Simplified transmission layer. """
def __init__(self, protocol):
self.protocol = protocol
self.data_buffer = b""
def connect(self, config_size):
""" Create connection. """
self.protocol.connect()
self.data_buffer = b""
# It will return with the Network configurations, which has the following struct:
# header [1] - size[1]
# configuration [config_size]
len_expected = config_size + 1
while len(self.data_buffer) < len_expected:
self.data_buffer += self.protocol.receive_data()
expected = struct.pack("B", config_size)
if self.data_buffer[0:1] != expected:
raise Exception("Unexpected configuration")
result = self.data_buffer[1:len_expected]
self.data_buffer = self.data_buffer[len_expected:]
return result
def close(self):
""" Close connection. """
self.protocol.close()
def send_message(self, _, data):
""" Send message. """
msg_size = len(data)
while msg_size > 0:
bytes_send = self.protocol.send_data(data)
if bytes_send < msg_size:
data = data[bytes_send:]
msg_size -= bytes_send
def get_message(self, blocking):
""" Receive message. """
# Connection was closed
if self.data_buffer is None:
return None
while True:
if len(self.data_buffer) >= 1:
size = ord(self.data_buffer[0])
if size == 0:
raise Exception("Unexpected data frame")
if len(self.data_buffer) >= size + 1:
result = self.data_buffer[1:size + 1]
self.data_buffer = self.data_buffer[size + 1:]
return result
if not blocking and not self.protocol.ready():
return b''
received_data = self.protocol.receive_data(MAX_BUFFER_SIZE)
if not received_data:
return None
self.data_buffer += received_data
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