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# -*- coding: utf-8 -*-
from __future__ import absolute_import
import struct
from io import BytesIO
from thriftpy._compat import CYTHON
from .. import TTransportBase, readall
from ..buffered import TBufferedTransport
class TFramedTransport(TTransportBase):
"""Class that wraps another transport and frames its I/O when writing."""
def __init__(self, trans):
self._trans = trans
self._rbuf = BytesIO()
self._wbuf = BytesIO()
def is_open(self):
return self._trans.is_open()
def open(self):
return self._trans.open()
def close(self):
return self._trans.close()
def read(self, sz):
# Important: don't attempt to read the next frame if the caller
# doesn't actually need any data.
if sz == 0:
return b''
ret = self._rbuf.read(sz)
if len(ret) != 0:
return ret
self.read_frame()
return self._rbuf.read(sz)
def read_frame(self):
buff = readall(self._trans.read, 4)
sz, = struct.unpack('!i', buff)
frame = readall(self._trans.read, sz)
self._rbuf = BytesIO(frame)
def write(self, buf):
self._wbuf.write(buf)
def flush(self):
# reset wbuf before write/flush to preserve state on underlying failure
out = self._wbuf.getvalue()
self._wbuf = BytesIO()
# N.B.: Doing this string concatenation is WAY cheaper than making
# two separate calls to the underlying socket object. Socket writes in
# Python turn out to be REALLY expensive, but it seems to do a pretty
# good job of managing string buffer operations without excessive
# copies
self._trans.write(struct.pack("!i", len(out)) + out)
self._trans.flush()
def getvalue(self):
return self._trans.getvalue()
class TFramedTransportFactory(object):
def get_transport(self, trans):
return TBufferedTransport(TFramedTransport(trans))
if CYTHON:
from .cyframed import TCyFramedTransport, TCyFramedTransportFactory # noqa
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