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"""
Wrappers to make file-like objects cooperative.
.. class:: FileObject
The main entry point to the file-like gevent-compatible behaviour. It will be defined
to be the best available implementation.
There are two main implementations of ``FileObject``. On all systems,
there is :class:`FileObjectThread` which uses the built-in native
threadpool to avoid blocking the entire interpreter. On UNIX systems
(those that support the :mod:`fcntl` module), there is also
:class:`FileObjectPosix` which uses native non-blocking semantics.
A third class, :class:`FileObjectBlock`, is simply a wrapper that executes everything
synchronously (and so is not gevent-compatible). It is provided for testing and debugging
purposes.
Configuration
=============
You may change the default value for ``FileObject`` using the
``GEVENT_FILE`` environment variable. Set it to ``posix``, ``thread``,
or ``block`` to choose from :class:`FileObjectPosix`,
:class:`FileObjectThread` and :class:`FileObjectBlock`, respectively.
You may also set it to the fully qualified class name of another
object that implements the file interface to use one of your own
objects.
.. note:: The environment variable must be set at the time this module
is first imported.
Classes
=======
"""
from __future__ import absolute_import
from gevent._config import config
__all__ = [
'FileObjectPosix',
'FileObjectThread',
'FileObjectBlock',
'FileObject',
]
try:
from fcntl import fcntl
except ImportError:
__all__.remove("FileObjectPosix")
else:
del fcntl
from gevent._fileobjectposix import FileObjectPosix
from gevent._fileobjectcommon import FileObjectThread
from gevent._fileobjectcommon import FileObjectBlock
# None of the possible objects can live in this module because
# we would get an import cycle and the config couldn't be set from code.
FileObject = config.fileobject