Source code for cherrypy.lib
"""CherryPy Library."""
[docs]def is_iterator(obj):
"""Detect if the object provided implements the iterator protocol.
(i.e. like a generator).
This will return False for objects which are iterable, but not
iterators themselves.
"""
from types import GeneratorType
if isinstance(obj, GeneratorType):
return True
elif not hasattr(obj, '__iter__'):
return False
else:
# Types which implement the protocol must return themselves when
# invoking 'iter' upon them.
return iter(obj) is obj
[docs]def is_closable_iterator(obj):
"""Detect if the given object is both closable and iterator."""
# Not an iterator.
if not is_iterator(obj):
return False
# A generator - the easiest thing to deal with.
import inspect
if inspect.isgenerator(obj):
return True
# A custom iterator. Look for a close method...
if not (hasattr(obj, 'close') and callable(obj.close)):
return False
# ... which doesn't require any arguments.
try:
inspect.getcallargs(obj.close)
except TypeError:
return False
else:
return True
[docs]class file_generator(object):
"""Yield the given input (a file object) in chunks (default 64k).
(Core)
"""
def __init__(self, input, chunkSize=65536):
"""Initialize file_generator with file ``input`` for chunked access."""
self.input = input
self.chunkSize = chunkSize
def __iter__(self):
"""Return iterator."""
return self
def __next__(self):
"""Return next chunk of file."""
chunk = self.input.read(self.chunkSize)
if chunk:
return chunk
else:
if hasattr(self.input, 'close'):
self.input.close()
raise StopIteration()
next = __next__
def __del__(self):
"""Close input on descturct."""
if hasattr(self.input, 'close'):
self.input.close()
[docs]def file_generator_limited(fileobj, count, chunk_size=65536):
"""Yield the given file object in chunks.
Stopps after `count` bytes has been emitted.
Default chunk size is 64kB. (Core)
"""
remaining = count
while remaining > 0:
chunk = fileobj.read(min(chunk_size, remaining))
chunklen = len(chunk)
if chunklen == 0:
return
remaining -= chunklen
yield chunk
