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Portable file locking utilities.

Based partially on an example by Jonathan Feignberg in the Python
Cookbook [1] (licensed under the Python Software License) and a ctypes port by
Anatoly Techtonik for Roundup [2] (license [3]).

[1] http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/65203
[2] https://sourceforge.net/p/roundup/code/ci/default/tree/roundup/backends/portalocker.py
[3] https://sourceforge.net/p/roundup/code/ci/default/tree/COPYING.txt

Example Usage::

    >>> from django.core.files import locks
    >>> with open('./file', 'wb') as f:
    ...     locks.lock(f, locks.LOCK_EX)
    ...     f.write('Django')
é    N)ÚLOCK_EXÚLOCK_SHÚLOCK_NBÚlockÚunlockc                 C   s   t | dƒr|  ¡ S | S )zCGet a filedescriptor from something which could be a file or an fd.Úfileno)Úhasattrr   ©Úf© r   ú;/tmp/pip-unpacked-wheel-gcyiijx6/django/core/files/locks.pyÚ_fd   s    r   Únt)	ÚPOINTERÚ	StructureÚUnionÚbyrefÚc_int64Úc_ulongÚc_void_pÚsizeofÚwindll)ÚBOOLÚDWORDÚHANDLEé   é   c                   @   s   e Zd ZdefdefgZdS )Ú_OFFSETZOffsetZ
OffsetHighN)Ú__name__Ú
__module__Ú__qualname__r   Ú_fields_r   r   r   r   r   2   s   þr   c                   @   s"   e Zd ZdgZdefdefgZdS )Ú_OFFSET_UNIONÚ_offsetZPointerN)r   r   r    Ú_anonymous_r   ÚPVOIDr!   r   r   r   r   r"   7   s   þr"   c                   @   s.   e Zd ZdgZdefdefdefdefgZdS )Ú
OVERLAPPEDZ_offset_unionZInternalZInternalHighZhEventN)r   r   r    r$   Ú	ULONG_PTRr"   r   r!   r   r   r   r   r&   =   s   ür&   c                 C   s2   t  t| ƒ¡}tƒ }t||dddt|ƒƒ}t|ƒS ©Nr   l     þ )ÚmsvcrtÚget_osfhandler   r&   Ú
LockFileExr   Úbool)r
   ÚflagsÚhfileÚ
overlappedÚretr   r   r   r   O   s    r   c                 C   s0   t  t| ƒ¡}tƒ }t|dddt|ƒƒ}t|ƒS r(   )r)   r*   r   r&   ÚUnlockFileExr   r,   )r
   r.   r/   r0   r   r   r   r   U   s    r   c                 C   s   dS )NFr   ©r
   r-   r   r   r   r   e   s    c                 C   s   dS ©NTr   r	   r   r   r   r   i   s    c                 C   s2   zt  t| ƒ|¡ W dS  tk
r,   Y dS X d S )NTF)ÚfcntlÚflockr   ÚBlockingIOErrorr2   r   r   r   r   m   s
    c                 C   s   t  t| ƒt j¡ dS r3   )r4   r5   r   ZLOCK_UNr	   r   r   r   r   t   s    )'Ú__doc__ÚosÚ__all__r   Únamer)   Úctypesr   r   r   r   r   r   r   r   r   Zctypes.wintypesr   r   r   r   r   r   r'   r%   r   r"   r&   ZLPOVERLAPPEDÚkernel32r+   ÚrestypeÚargtypesr1   r   r   r4   ÚImportErrorÚAttributeErrorr   r   r   r   Ú<module>   sJ   ,

