Edit File: attr.cpython-37.pyc
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The attribute mechanics here spend effort trying to ensure listener functions are available with a minimum of function call overhead, that unnecessary objects aren't created (i.e. many empty per-instance listener collections), as well as that everything is garbage collectable when owning references are lost. Other features such as "propagation" of listener functions across many ``_Dispatch`` instances, "joining" of multiple ``_Dispatch`` instances, as well as support for subclass propagation (e.g. events assigned to ``Pool`` vs. ``QueuePool``) are all implemented here. � )�absolute_import)�with_statementN)�chain� )�legacy)�registry� )�exc)�util)� threadingc @ s e Zd ZdZdd� ZdS )� RefCollection)�refc C s t �| tj�S )N)�weakrefr r Z_collection_gced)�self� r �H/opt/alt/python37/lib64/python3.7/site-packages/sqlalchemy/event/attr.py�_memoized_attr_ref1 s z RefCollection._memoized_attr_refN)�__name__� __module__� __qualname__� __slots__r r r r r r . s r c @ s4 e Zd Zdd� Zdd� Zdd� Zdd� Zd d � Zd S ) �_empty_collectionc C s d S )Nr )r �elementr r r �append6 s z_empty_collection.appendc C s d S )Nr )r �otherr r r �extend9 s z_empty_collection.extendc C s d S )Nr )r r r r r �remove< s z_empty_collection.removec C s t g �S )N)�iter)r r r r �__iter__? s z_empty_collection.__iter__c C s d S )Nr )r r r r �clearB s z_empty_collection.clearN)r r r r r r r r r r r r r 5 s r c @ sd e Zd ZdZdZdd� Zdd� Zdd� Zd d � Zd d � Z d d� Z dd� Z dd� Z dd� Z dd� ZdS )�_ClsLevelDispatchz2Class-level events on :class:`._Dispatch` classes.)�name� arg_names�has_kw�legacy_signatures� _clslevel� __weakref__c C sn |j | _t�|�}|jdd � | _t|j�| _t t t t |dg �dd� d���| _ t�| ||�|_t�� | _d S )Nr Z_legacy_signaturesc S s | d S )Nr r )�sr r r �<lambda>Z � z,_ClsLevelDispatch.__init__.<locals>.<lambda>)�key)r r! r Zinspect_getfullargspec�argsr" �bool�varkwr# �list�reversed�sorted�getattrr$ r Z_augment_fn_docs�__doc__r �WeakKeyDictionaryr% )r Zparent_dispatch_cls�fn�argspecr r r �__init__R s z_ClsLevelDispatch.__init__c C sN |r| � |�}| jrJytj|dd�}W n tk r: Y nX t�| ||�}|S )NT)Zno_self)�_wrap_fn_for_kwr$ r Zget_callable_argspec� TypeErrorr Z_wrap_fn_for_legacy)r r4 �namedr5 r r r �_adjust_fn_specb s z!_ClsLevelDispatch._adjust_fn_specc s � �fdd�}|S )Nc s$ t t�j| ��}|�|� � f |�S )N)�dict�zipr" �update)r+ �kwZargdict)r4 r r r �wrap_kwo s z2_ClsLevelDispatch._wrap_fn_for_kw.<locals>.wrap_kwr )r r4 r? r )r4 r r r7 n s z!_ClsLevelDispatch._wrap_fn_for_kwc C s� |j }t|t�std��t|dd�s2t�d| ��|g}xd|r�|�d�}|�|� � � ||k rt|| j krt| � |� q:|| j kr�| � |� | j | � |j� q:W t�|| � d S )Nz*Class-level Event targets must be classes.�_sa_propagate_class_eventsTz.Can't assign an event directly to the %s classr )�dispatch_target� isinstance�type�AssertionErrorr1 r �InvalidRequestError�popr �__subclasses__r% �update_subclass�_assign_cls_collection� appendleft� _listen_fnr �_stored_in_collection)r � event_key� propagate�target�stack�clsr r r �insertv s" z_ClsLevelDispatch.insertc C s� |j }t|t�std��t|dd�s2t�d| ��|g}xd|r�|�d�}|�|� � � ||k rt|| j krt| � |� q:|| j kr�| � |� | j | � |j� q:W t�|| � d S )Nz*Class-level Event targets must be classes.r@ Tz.Can't assign an event directly to the %s classr )rA rB rC rD r1 r rE rF r rG r% rH rI r rK r rL )r rM rN rO rP rQ r r r r � s" z_ClsLevelDispatch.appendc C s, t |dd�r t�� | j|< n t� | j|< d S )Nr@ T)r1 � collections�dequer% r )r rO r r r rI � s z(_ClsLevelDispatch._assign_cls_collectionc sb || j kr| �|� | j | � x>|jdd � D ],}|| j kr.� �� fdd�| j | D �� q.W d S )Nr c s g | ]}|� kr|�qS r r )�.0r4 )�clslevelr r � <listcomp>� s z5_ClsLevelDispatch.update_subclass.<locals>.<listcomp>)r% rI �__mro__r )r rO rQ r )rV r rH � s z!_ClsLevelDispatch.update_subclassc C sZ |j }|g}x<|rH|�d�}|�|�� � || jkr| j| �|j� qW t�|| � d S )Nr ) rA rF r rG r% r rK r �_removed_from_collection)r rM rO rP rQ r r r r � s z_ClsLevelDispatch.removec C s< t � }x$| j�� D ]}|�|� |�� qW t�| |� dS )z Clear all class level listenersN)�setr% �valuesr= r r �_clear)r Zto_clearZ dispatcherr r r r � s z_ClsLevelDispatch.clearc C s | S )z�Return an event collection which can be modified. 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Represents a collection of listeners. As of 0.7.9, _ListenerCollection is only first created via the _EmptyListener.for_modify() method. )rb r` r! ro rN r& c C sJ ||j kr|�|� d| _|j | | _|| _|j| _t�� | _t � | _ d S )NF) r% rH rt rb r` r! rS rT ro rZ rN )r r` rc r r r r6 J s z _ListenerCollection.__init__c C s | S )z�Return an event collection which can be modified. 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