/usr/lib/python3/dist-packages/cachecontrol/filewrapper.py is in python3-cachecontrol 0.11.7-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 | 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 _close(self):
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
def read(self, amt=None):
data = self.__fp.read(amt)
self.__buf.write(data)
if self.__is_fp_closed():
self._close()
return data
def _safe_read(self, amt):
data = self.__fp._safe_read(amt)
if amt == 2 and data == b'\r\n':
# urllib executes this read to toss the CRLF at the end
# of the chunk.
return data
self.__buf.write(data)
if self.__is_fp_closed():
self._close()
return data
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