mirror of
https://github.com/SickGear/SickGear.git
synced 2024-12-01 08:53:37 +00:00
64 lines
2.1 KiB
Python
64 lines
2.1 KiB
Python
|
from io import BytesIO
|
||
|
|
|
||
|
|
|
||
|
|
class CallbackFileWrapper(object):
|
||
|
|
"""
|
||
|
|
Small wrapper around a fp object which will tee everything read into a
|
||
|
|
buffer, and when that file is closed it will execute a callback with the
|
||
|
|
contents of that buffer.
|
||
|
|
|
||
|
|
All attributes are proxied to the underlying file object.
|
||
|
|
|
||
|
|
This class uses members with a double underscore (__) leading prefix so as
|
||
|
|
not to accidentally shadow an attribute.
|
||
|
|
"""
|
||
|
|
|
||
|
|
def __init__(self, fp, callback):
|
||
|
|
self.__buf = BytesIO()
|
||
|
|
self.__fp = fp
|
||
|
|
self.__callback = callback
|
||
|
|
|
||
|
|
def __getattr__(self, name):
|
||
|
|
# The vaguaries of garbage collection means that self.__fp is
|
||
|
|
# not always set. By using __getattribute__ and the private
|
||
|
|
# name[0] allows looking up the attribute value and raising an
|
||
|
|
# AttributeError when it doesn't exist. This stop thigns from
|
||
|
|
# infinitely recursing calls to getattr in the case where
|
||
|
|
# self.__fp hasn't been set.
|
||
|
|
#
|
||
|
|
# [0] https://docs.python.org/2/reference/expressions.html#atom-identifiers
|
||
|
|
fp = self.__getattribute__('_CallbackFileWrapper__fp')
|
||
|
|
return getattr(fp, name)
|
||
|
|
|
||
|
|
def __is_fp_closed(self):
|
||
|
|
try:
|
||
|
|
return self.__fp.fp is None
|
||
|
|
except AttributeError:
|
||
|
|
pass
|
||
|
|
|
||
|
|
try:
|
||
|
|
return self.__fp.closed
|
||
|
|
except AttributeError:
|
||
|
|
pass
|
||
|
|
|
||
|
|
# We just don't cache it then.
|
||
|
|
# TODO: Add some logging here...
|
||
|
|
return False
|
||
|
|
|
||
|
|
def read(self, amt=None):
|
||
|
|
data = self.__fp.read(amt)
|
||
|
|
self.__buf.write(data)
|
||
|
|
|
||
|
|
if self.__is_fp_closed():
|
||
|
|
if self.__callback:
|
||
|
|
self.__callback(self.__buf.getvalue())
|
||
|
|
|
||
|
|
# We assign this to None here, because otherwise we can get into
|
||
|
|
# really tricky problems where the CPython interpreter dead locks
|
||
|
|
# because the callback is holding a reference to something which
|
||
|
|
# has a __del__ method. Setting this to None breaks the cycle
|
||
|
|
# and allows the garbage collector to do it's thing normally.
|
||
|
|
self.__callback = None
|
||
|
|
|
||
|
|
return data
|