a
�M�e�
� @ s� U d dl mZ d dlZd dlmZmZmZmZ da i Z
ee ef e d< dZ
G dd� dejj�Ze ed�d d
�Ze d �d d
�Zed �dd�Ze ed�dd�ZdS )� )�DictN)�Backend�DatagramSocket�Socket� StreamSocket� _backendsFc @ s e Zd ZdS )�AsyncLibraryNotFoundErrorN)�__name__�
__module__� __qualname__� r r �4/usr/lib/python3.9/site-packages/dns/asyncbackend.pyr s r )�name�returnc C sd t �| �}|r|S | dkr.ddl}|j�� }n*| dkrJddl}|j�� }ntd| � ���|t | < |S )z�Get the specified asynchronous backend.
*name*, a ``str``, the name of the backend. Currently the "trio"
and "asyncio" backends are available.
Raises NotImplementedError if an unknown backend name is specified.
Ztrior N�asyncioz unimplemented async backend )r �getZdns._trio_backendZ
_trio_backendr Zdns._asyncio_backendZ_asyncio_backend�NotImplementedError)r Zbackend�dnsr r r
� get_backend s
r )r c C s� z>t r
t�ddl} z | �� W W S | jy: td��Y n0 W nF ty� ddl}z|�� W Y dS ty~ td��Y n0 Y n0 dS )z�Attempt to determine the in-use asynchronous I/O library by using
the ``sniffio`` module if it is available.
Returns the name of the library, or raises AsyncLibraryNotFoundError
if the library cannot be determined.
r Nz&sniffio cannot determine async libraryr zno async library detected)� _no_sniffio� ImportError�sniffioZcurrent_async_libraryr r Zget_running_loop� RuntimeError)r r r r r
�sniff7 s r c C s t rt S tt� �S )z6Get the default backend, initializing it if necessary.)�_default_backend�set_default_backendr r r r r
�get_default_backendR s r c C s t | �atS )a, Set the default backend.
It's not normally necessary to call this method, as
``get_default_backend()`` will initialize the backend
appropriately in many cases. If ``sniffio`` is not installed, or
in testing situations, this function allows the backend to be set
explicitly.
)r r )r r r r
r Z s
r )�typingr Z
dns.exceptionr Zdns._asyncbackendr r r r r r �str�__annotations__r � exceptionZ DNSExceptionr r r r r r r r r
�<module> s