3
v^!                 @   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	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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   >/usr/lib/python3.6/site-packages/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resultresult_paramsZfull_neededZempty_neededchildsqlparamsconnZ
sql_stringr   r   r   as_sqlA   s<    




zWhereNode.as_sqlNc             C   s&   g }x| j D ]}|j|j  qW |S )N)r   r   get_group_by_cols)r   aliascolsr   r   r   r   r$   u   s    zWhereNode.get_group_by_colsc             C   s   | j d d  S )N)r   )r   r   r   r   get_source_expressions{   s    z WhereNode.get_source_expressionsc             C   s    t |t | jkst|| _d S )N)r   r   AssertionError)r   r   r   r   r   set_source_expressions~   s    z WhereNode.set_source_expressionsc             C   sL   xFt | jD ]8\}}t|dr*|j| qt|dr|j|| j|< qW dS )z
        Relabel the alias values of any children. 'change_map' is a dictionary
        mapping old (current) alias values to the new values.
        relabel_aliasesrelabeled_cloneN)	enumerater   r   r*   r+   )r   
change_mapposr   r   r   r   r*      s
    

zWhereNode.relabel_aliasesc             C   sR   | j jg | j| jd}x6| jD ],}t|dr>|jj|j  q|jj| qW |S )z
        Create a clone of the tree. Must only be called on root nodes (nodes
        with empty subtree_parents). Childs must be either (Constraint, lookup,
        value) tuples, or objects supporting .clone().
        )r   r   r
   clone)r   _new_instancer   r
   r   r   r   r/   )r   r/   r   r   r   r   r/      s    
zWhereNode.clonec             C   s   | j  }|j| |S )N)r/   r*   )r   r-   r/   r   r   r   r+      s    
zWhereNode.relabeled_clonec                s*   t |tjr$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	   )r3   objr   )r3   r   r1      s    zWhereNode._contains_aggregatec             C   s
   | j | S )N)r1   )r   r   r   r   r	      s    zWhereNode.contains_aggregatec                s*   t |tjr$t fdd|jD S |jS )Nc             3   s   | ]} j |V  qd S )N)_contains_over_clause)r2   r   )r3   r   r   r4      s    z2WhereNode._contains_over_clause.<locals>.<genexpr>)r5   r   r6   r7   r   contains_over_clause)r3   r8   r   )r3   r   r9      s    zWhereNode._contains_over_clausec             C   s
   | j | S )N)r9   )r   r   r   r   r:      s    zWhereNode.contains_over_clausec             C   s   t dd | jD S )Nc             s   s   | ]}|j V  qd S )N)
is_summary)r2   r   r   r   r   r4      s    z'WhereNode.is_summary.<locals>.<genexpr>)r7   r   )r   r   r   r   r;      s    zWhereNode.is_summaryc             O   s    t | dr| j|f||} | S )Nresolve_expression)r   r<   )exprqueryargskwargsr   r   r   _resolve_leaf   s    
zWhereNode._resolve_leafc             O   sv   t |dr.x"|jD ]}| j||f|| qW t |drP| j|j|f|||_t |drr| j|j|f|||_d S )Nr   lhsrhs)r   r   _resolve_noderA   rB   rC   )r3   noder>   r?   r@   r   r   r   r   rD      s    


zWhereNode._resolve_nodec             O   s$   | j  }|j|f|| d|_|S )NT)r/   rD   r   )r   r?   r@   r/   r   r   r   r<      s    zWhereNode.resolve_expression)F)N)__name__
__module____qualname____doc__r   defaultr   conditionalr   r#   r$   r'   r)   r*   r/   r+   classmethodr1   r   r	   r9   r:   propertyr;   staticmethodrA   rD   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)rF   rG   rH   rI   r	   r#   r   r   r   r   rO      s   rO   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   rQ   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   )r2   r    r   r   r   
<listcomp>   s    z%ExtraWhere.as_sql.<locals>.<listcomp>z AND )rQ   r   listr!   )r   r   r   rQ   r   r   r   r#      s    zExtraWhere.as_sql)NN)rF   rG   rH   r	   rR   r#   r   r   r   r   rP      s   rP   c               @   s    e Zd ZdZdd Zdd ZdS )SubqueryConstraintFc             C   s   || _ || _|| _|| _d S )N)r%   columnstargetsquery_object)r   r%   rV   rW   rX   r   r   r   rR      s    zSubqueryConstraint.__init__c             C   s0   | j }|j| j |j|d}|j| j| j|S )N)r   )rX   
set_valuesrW   get_compilerZas_subquery_conditionr%   rV   )r   r   r   r>   Zquery_compilerr   r   r   r#      s    zSubqueryConstraint.as_sqlN)rF   rG   rH   r	   rR   r#   r   r   r   r   rU      s   rU   N)rI   django.core.exceptionsr   django.utilsr   django.utils.functionalr   r   r   r6   r   rO   rP   rU   r   r   r   r   <module>   s    D