Make all fields private

This commit is contained in:
Erik Johnston 2018-01-18 11:10:12 +00:00
parent dc519602ac
commit 2f18a2647b

View File

@ -35,24 +35,24 @@ class BackgroundFileConsumer(object):
_RESUME_ON_QUEUE_SIZE = 2
def __init__(self, file_obj):
self.file_obj = file_obj
self._file_obj = file_obj
# Producer we're registered with
self.producer = None
self._producer = None
# True if PushProducer, false if PullProducer
self.streaming = False
# For PushProducers, indicates whether we've paused the producer and
# need to call resumeProducing before we get more data.
self.paused_producer = False
self._paused_producer = False
# Queue of slices of bytes to be written. When producer calls
# unregister a final None is sent.
self.bytes_queue = Queue.Queue()
self._bytes_queue = Queue.Queue()
# Deferred that is resolved when finished writing
self.finished_deferred = None
self._finished_deferred = None
# If the _writer thread throws an exception it gets stored here.
self._write_exception = None
@ -69,21 +69,21 @@ class BackgroundFileConsumer(object):
streaming (bool): True if push based producer, False if pull
based.
"""
if self.producer:
if self._producer:
raise Exception("registerProducer called twice")
self.producer = producer
self._producer = producer
self.streaming = streaming
self.finished_deferred = threads.deferToThread(self._writer)
self._finished_deferred = threads.deferToThread(self._writer)
if not streaming:
self.producer.resumeProducing()
self._producer.resumeProducing()
def unregisterProducer(self):
"""Part of IProducer interface
"""
self.producer = None
if not self.finished_deferred.called:
self.bytes_queue.put_nowait(None)
self._producer = None
if not self._finished_deferred.called:
self._bytes_queue.put_nowait(None)
def write(self, bytes):
"""Part of IProducer interface
@ -91,65 +91,65 @@ class BackgroundFileConsumer(object):
if self._write_exception:
raise self._write_exception
if self.finished_deferred.called:
if self._finished_deferred.called:
raise Exception("consumer has closed")
self.bytes_queue.put_nowait(bytes)
self._bytes_queue.put_nowait(bytes)
# If this is a PushProducer and the queue is getting behind
# then we pause the producer.
if self.streaming and self.bytes_queue.qsize() >= self._PAUSE_ON_QUEUE_SIZE:
self.paused_producer = True
self.producer.pauseProducing()
if self.streaming and self._bytes_queue.qsize() >= self._PAUSE_ON_QUEUE_SIZE:
self._paused_producer = True
self._producer.pauseProducing()
def _writer(self):
"""This is run in a background thread to write to the file.
"""
try:
while self.producer or not self.bytes_queue.empty():
while self._producer or not self._bytes_queue.empty():
# If we've paused the producer check if we should resume the
# producer.
if self.producer and self.paused_producer:
if self.bytes_queue.qsize() <= self._RESUME_ON_QUEUE_SIZE:
if self._producer and self._paused_producer:
if self._bytes_queue.qsize() <= self._RESUME_ON_QUEUE_SIZE:
reactor.callFromThread(self._resume_paused_producer)
if self._notify_empty_deferred and self.bytes_queue.empty():
if self._notify_empty_deferred and self._bytes_queue.empty():
reactor.callFromThread(self._notify_empty)
bytes = self.bytes_queue.get()
bytes = self._bytes_queue.get()
# If we get a None (or empty list) then that's a signal used
# to indicate we should check if we should stop.
if bytes:
self.file_obj.write(bytes)
self._file_obj.write(bytes)
# If its a pull producer then we need to explicitly ask for
# more stuff.
if not self.streaming and self.producer:
reactor.callFromThread(self.producer.resumeProducing)
if not self.streaming and self._producer:
reactor.callFromThread(self._producer.resumeProducing)
except Exception as e:
self._write_exception = e
raise
finally:
self.file_obj.close()
self._file_obj.close()
def wait(self):
"""Returns a deferred that resolves when finished writing to file
"""
return make_deferred_yieldable(self.finished_deferred)
return make_deferred_yieldable(self._finished_deferred)
def _resume_paused_producer(self):
"""Gets called if we should resume producing after being paused
"""
if self.paused_producer and self.producer:
self.paused_producer = False
self.producer.resumeProducing()
if self._paused_producer and self._producer:
self._paused_producer = False
self._producer.resumeProducing()
def _notify_empty(self):
"""Called when the _writer thread thinks the queue may be empty and
we should notify anything waiting on `wait_for_writes`
"""
if self._notify_empty_deferred and self.bytes_queue.empty():
if self._notify_empty_deferred and self._bytes_queue.empty():
d = self._notify_empty_deferred
self._notify_empty_deferred = None
d.callback(None)