class TMemoryOutputBuffer(TMemoryBuffer, object):
"""
An implementation of TMemoryBuffer using a bounded memory buffer. Writes
that cause the buffer to exceed its size throw an FMessageSizeException.
This implementation handles framing data.
"""
def __init__(self, limit, value=None):
"""
Create an instance of FBoundedMemoryBuffer where size is the
maximum writable length of the buffer.
Args:
limit: integer size limit of the buffer
value: optional data value to initialize the buffer with.
"""
super(TMemoryOutputBuffer, self).__init__(value)
self._limit = limit
def write(self, buf):
"""
Bounded write to buffer
"""
if len(self) + len(buf) > self._limit > 0:
self._buffer = TMemoryBuffer()
raise TTransportException(
type=TTransportExceptionType.REQUEST_TOO_LARGE,
message="Buffer size reached {}".format(self._limit))
self._buffer.write(buf)
def getvalue(self):
# TODO make more efficient?
data = self._buffer.getvalue()
return struct.pack('!I', len(data)) + data
def read(self, sz):
raise Exception("don't call this")
def __len__(self):
return len(self.getvalue())
def testNoInitialValue(self):
buf = TMemoryBuffer()
data = buf.read(5)
buf.write(b"world")
self.assertEquals(data, b"")
self.assertEquals(buf.getvalue(), b"world")
def testReadWrite(self):
buf = TMemoryBuffer(b"hello")
data = buf.read(5)
buf.write(b"world")
self.assertEquals(data, b"hello")
self.assertEquals(buf.getvalue(), b"world")
def testNoInitialValue(self):
buf = TMemoryBuffer()
data = buf.read(5)
buf.write(b"world")
self.assertEquals(data, b"")
self.assertEquals(buf.getvalue(), b"world")
def testReadWrite(self):
buf = TMemoryBuffer(b"hello")
data = buf.read(5)
buf.write(b"world")
self.assertEquals(data, b"hello")
self.assertEquals(buf.getvalue(), b"world")
