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     Q$                     @   s   d Z ddlZddlZddlZddlZze W n ey#   dd ZY nw ejdk r4edZ	edZ
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dZG dd deZdS )z-Refactored 'safe reference from dispatcher.py    Nc                 C   s
   t | dS )N__call__)hasattr)object r   2/usr/lib/python3/dist-packages/blinker/_saferef.pycallable.   s   
r   )   im_selfim_func__self____func__c                 C   s~   zt | }W n ty    t|rt| | Y S t|  Y S w |dur=t| ds5t| ds5J d|  t| |d}|S dS )a  Return a *safe* weak reference to a callable target.

    - ``target``: The object to be weakly referenced, if it's a bound
      method reference, will create a BoundMethodWeakref, otherwise
      creates a simple weakref.

    - ``on_delete``: If provided, will have a hard reference stored to
      the callable to be called after the safe reference goes out of
      scope with the reference object, (either a weakref or a
      BoundMethodWeakref) as argument.
    Nr
   r   zRsafe_ref target %r has im_self, but no im_func, don't know how to create reference)target	on_delete)get_selfAttributeErrorr   weakrefrefr   BoundMethodWeakref)r   r   r	   	referencer   r   r   safe_ref:   s    r   c                       sh   e Zd ZdZe Zd fdd	ZdddZdd Z	e
e	Z	d	d
 ZeZdd Zdd Zdd Z  ZS )r   a  'Safe' and reusable weak references to instance methods.

    BoundMethodWeakref objects provide a mechanism for referencing a
    bound method without requiring that the method object itself
    (which is normally a transient object) is kept alive.  Instead,
    the BoundMethodWeakref object keeps weak references to both the
    object and the function which together define the instance method.

    Attributes:

    - ``key``: The identity key for the reference, calculated by the
      class's calculate_key method applied to the target instance method.

    - ``deletion_methods``: Sequence of callable objects taking single
      argument, a reference to this object which will be called when
      *either* the target object or target function is garbage
      collected (i.e. when this object becomes invalid).  These are
      specified as the on_delete parameters of safe_ref calls.

    - ``weak_self``: Weak reference to the target object.

    - ``weak_func``: Weak reference to the target function.

    Class Attributes:

    - ``_all_instances``: Class attribute pointing to all live
      BoundMethodWeakref objects indexed by the class's
      calculate_key(target) method applied to the target objects.
      This weak value dictionary is used to short-circuit creation so
      that multiple references to the same (object, function) pair
      produce the same BoundMethodWeakref instance.
    Nc                    sf   |  |}| j|}|dur|j| |S tt| | }|| j|< |j||g|R i | |S )a  Create new instance or return current instance.

        Basically this method of construction allows us to
        short-circuit creation of references to already- referenced
        instance methods.  The key corresponding to the target is
        calculated, and if there is already an existing reference,
        that is returned, with its deletion_methods attribute updated.
        Otherwise the new instance is created and registered in the
        table of already-referenced methods.
        N)	calculate_key_all_instancesgetdeletion_methodsappendsuperr   __new____init__)clsr   r   	argumentsnamedkeycurrentbase	__class__r   r   r   |   s   

zBoundMethodWeakref.__new__c                 C   sf   | fdd}|g| _ | || _t|}t|}t||| _t||| _t	|| _
t	|j| _dS )a  Return a weak-reference-like instance for a bound method.

        - ``target``: The instance-method target for the weak reference,
          must have im_self and im_func attributes and be
          reconstructable via the following, which is true of built-in
          instance methods::

            target.im_func.__get__( target.im_self )

        - ``on_delete``: Optional callback which will be called when
          this weak reference ceases to be valid (i.e. either the
          object or the function is garbage collected).  Should take a
          single argument, which will be passed a pointer to this
          object.
        c                 S   s   |j dd }|j dd= z|jj|j= W n	 ty   Y nw |D ]4}z
t|r,|| W q! tyU   zt  W n t	yR   t
 d }td|||f  Y nw Y q!w dS )z=Set self.isDead to True when method or instance is destroyed.N   z3Exception during saferef %s cleanup function %s: %s)r   r%   r   r!   KeyErrorr   	Exception	traceback	print_excr   sysexc_infoprint)weakselfmethodsfunctioner   r   r   remove   s0   
z+BoundMethodWeakref.__init__.<locals>.removeN)r   r   r!   r   get_funcr   r   	weak_self	weak_funcstr	self_name__name__	func_name)r/   r   r   r3   r	   r
   r   r   r   r      s   
zBoundMethodWeakref.__init__c                 C   s   t t|t t|fS )zCalculate the reference key for this reference.

        Currently this is a two-tuple of the id()'s of the target
        object and the target function respectively.
        )idr   r4   )r   r   r   r   r   r      s   z BoundMethodWeakref.calculate_keyc                 C   s   d| j j| j| jf S )z-Give a friendly representation of the object.z	%s(%s.%s))r%   r9   r8   r:   r/   r   r   r   __str__   s
   zBoundMethodWeakref.__str__c                 C   s
   |  duS )z'Whether we are still a valid reference.Nr   r<   r   r   r   __nonzero__   s   
zBoundMethodWeakref.__nonzero__c                 C   s*   t || jst| jt|S t| j|jS )zCompare with another reference.)
isinstancer%   cmptyper!   )r/   otherr   r   r   __cmp__   s   zBoundMethodWeakref.__cmp__c                 C   s.   |   }|dur|  }|dur||S dS )a?  Return a strong reference to the bound method.

        If the target cannot be retrieved, then will return None,
        otherwise returns a bound instance method for our object and
        function.

        Note: You may call this method any number of times, as it does
        not invalidate the reference.
        N)r5   r6   __get__)r/   r   r1   r   r   r   r      s   

zBoundMethodWeakref.__call__N)r9   
__module____qualname____doc__r   WeakValueDictionaryr   r   r   r   classmethodr=   __repr__r>   rC   r   __classcell__r   r   r$   r   r   X   s    !
,r   rE   )rH   operatorr+   r)   r   r   	NameErrorversion_info
attrgetterr   r4   r   r   r   r   r   r   r   <module>   s"   "



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