3
7^7                 @   sp   d Z ddlmZ ddlmZ ddlmZ dZdZG dd dej	Z
G d	d
 d
ZG dd dZG dd dZdS )zG
Code to manage the creation and SQL rendering of 'where' constraints.
    )EmptyResultSet)tree)cached_propertyANDORc               @   s   e Zd ZdZeZdZdZd!ddZdd Z	dd	 Z
d
d Zdd Zdd Zdd Zdd Zedd Zedd Zedd Zedd Zedd Zdd Zd S )"	WhereNodea  
    An SQL WHERE clause.

    The class is tied to the Query class that created it (in order to create
    the correct SQL).

    A child is usually an expression producing boolean values. Most likely the
    expression is a Lookup instance.

    However, a child could also be any class with as_sql() and either
    relabeled_clone() method or relabel_aliases() and clone() methods and
    contains_aggregate attribute.
    FTc             C   s   | j s| dfS || jA }|r&| jtkp4| o4| jtk}|rH| j rHd| fS g }g }xh| jD ]^}t|dr|j|\}}|dk	r|j| |dk	r|j| qX|j r|j| qX|j| qXW |r| j	|| j| jnd}	|r| j	|| j| jnd}
|
|	fS )z
        Return two possibly None nodes: one for those parts of self that
        should be included in the WHERE clause and one for those parts of
        self that must be included in the HAVING clause.
        Nsplit_having)
contains_aggregatenegated	connectorr   r   childrenhasattrr   append	__class__)selfr
   Z
in_negatedZmay_need_splitZwhere_partsZhaving_partscZ
where_partZhaving_partZhaving_nodeZ
where_node r   </tmp/pip-build-8app2_gc/Django/django/db/models/sql/where.pyr       s,    



zWhereNode.split_havingc             C   s  g }g }| j tkr$t| jd }}ndt| j }}x| jD ]}y|j|\}}	W n tk
rn   |d8 }Y n$X |r|j| |j|	 n|d8 }|dkr| jrdg fS t|dkr<| jrtq<dg fS q<W d| j  }
|
j	|}|r| jrd| }nt|dks| j
rd| }||fS )a  
        Return the SQL version of the where clause and the value to be
        substituted in. Return '', [] if this node matches everything,
        None, [] if this node is empty, and raise EmptyResultSet if this
        node can't match anything.
           r    z %s zNOT (%s)z(%s))r   r   lenr   compiler   r   extendr
   joinresolved)r   compiler
connectionresultZresult_paramsZfull_neededZempty_neededchildsqlparamsconnZ
sql_stringr   r   r   as_sqlA   s<    




zWhereNode.as_sqlc             C   s&   g }x| j D ]}|j|j  qW |S )N)r   r   get_group_by_cols)r   colsr   r   r   r   r#   u   s    zWhereNode.get_group_by_colsc             C   s   | j d d  S )N)r   )r   r   r   r   get_source_expressions{   s    z WhereNode.get_source_expressionsc             C   s    t |t | jkst|| _d S )N)r   r   AssertionError)r   r   r   r   r   set_source_expressions~   s    z WhereNode.set_source_expressionsc             C   sL   xFt | jD ]8\}}t|dr*|j| qt|dr|j|| j|< qW dS )z
        Relabel the alias values of any children. 'change_map' is a dictionary
        mapping old (current) alias values to the new values.
        relabel_aliasesrelabeled_cloneN)	enumerater   r   r(   r)   )r   
change_mapposr   r   r   r   r(      s
    

zWhereNode.relabel_aliasesc             C   sR   | j jg | j| jd}x6| jD ],}t|dr>|jj|j  q|jj| qW |S )z
        Create a clone of the tree. Must only be called on root nodes (nodes
        with empty subtree_parents). Childs must be either (Constraint, lookup,
        value) tuples, or objects supporting .clone().
        )r   r   r
   clone)r   Z_new_instancer   r
   r   r   r   r-   )r   r-   r   r   r   r   r-      s    
zWhereNode.clonec             C   s   | j  }|j| |S )N)r-   r(   )r   r+   r-   r   r   r   r)      s    
zWhereNode.relabeled_clonec                s*   t |tjr$t fdd|jD S |jS )Nc             3   s   | ]} j |V  qd S )N)_contains_aggregate).0r   )clsr   r   	<genexpr>   s    z0WhereNode._contains_aggregate.<locals>.<genexpr>)
isinstancer   Nodeanyr   r	   )r0   objr   )r0   r   r.      s    zWhereNode._contains_aggregatec             C   s
   | j | S )N)r.   )r   r   r   r   r	      s    zWhereNode.contains_aggregatec                s*   t |tjr$t fdd|jD S |jS )Nc             3   s   | ]} j |V  qd S )N)_contains_over_clause)r/   r   )r0   r   r   r1      s    z2WhereNode._contains_over_clause.<locals>.<genexpr>)r2   r   r3   r4   r   contains_over_clause)r0   r5   r   )r0   r   r6      s    zWhereNode._contains_over_clausec             C   s
   | j | S )N)r6   )r   r   r   r   r7      s    zWhereNode.contains_over_clausec             C   s   t dd | jD S )Nc             s   s   | ]}|j V  qd S )N)
is_summary)r/   r   r   r   r   r1      s    z'WhereNode.is_summary.<locals>.<genexpr>)r4   r   )r   r   r   r   r8      s    zWhereNode.is_summaryc             O   s   | j  }d|_|S )NT)r-   r   )r   argskwargsr-   r   r   r   resolve_expression   s    zWhereNode.resolve_expressionN)F)__name__
__module____qualname____doc__r   defaultr   Zconditionalr   r"   r#   r%   r'   r(   r-   r)   classmethodr.   r   r	   r6   r7   propertyr8   r;   r   r   r   r   r      s$   
!4r   c               @   s   e Zd ZdZdZdddZdS )NothingNodezA node that matches nothing.FNc             C   s   t d S )N)r   )r   r   r   r   r   r   r"      s    zNothingNode.as_sql)NN)r<   r=   r>   r?   r	   r"   r   r   r   r   rC      s   rC   c               @   s"   e Zd ZdZdd ZdddZdS )
ExtraWhereFc             C   s   || _ || _d S )N)sqlsr    )r   rE   r    r   r   r   __init__   s    zExtraWhere.__init__Nc             C   s(   dd | j D }dj|t| jp"f fS )Nc             S   s   g | ]}d | qS )z(%s)r   )r/   r   r   r   r   
<listcomp>   s    z%ExtraWhere.as_sql.<locals>.<listcomp>z AND )rE   r   listr    )r   r   r   rE   r   r   r   r"      s    zExtraWhere.as_sql)NN)r<   r=   r>   r	   rF   r"   r   r   r   r   rD      s   rD   c               @   s    e Zd ZdZdd Zdd ZdS )SubqueryConstraintFc             C   s   || _ || _|| _|| _d S )N)aliascolumnstargetsquery_object)r   rJ   rK   rL   rM   r   r   r   rF      s    zSubqueryConstraint.__init__c             C   s0   | j }|j| j |j|d}|j| j| j|S )N)r   )rM   Z
set_valuesrL   Zget_compilerZas_subquery_conditionrJ   rK   )r   r   r   queryZquery_compilerr   r   r   r"      s    zSubqueryConstraint.as_sqlN)r<   r=   r>   r	   rF   r"   r   r   r   r   rI      s   rI   N)r?   Zdjango.core.exceptionsr   Zdjango.utilsr   Zdjango.utils.functionalr   r   r   r3   r   rC   rD   rI   r   r   r   r   <module>   s    3