3
7^X'                 @   sx   d Z ddlmZ ddlmZ ddlmZ ddlmZ G dd deZ	G d	d
 d
e	Z
G dd de
ZG dd de	ZdS )al  
"Rel objects" for related fields.

"Rel objects" (for lack of a better name) carry information about the relation
modeled by a related field and provide some utility functions. They're stored
in the ``remote_field`` attribute of the field.

They also act as reverse fields for the purposes of the Meta API because
they're the closest concept currently available.
    )
exceptions)cached_property   )BLANK_CHOICE_DASH)FieldCacheMixinc               @   s
  e Zd ZdZdZdZdZdZdZd1d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e
dd Ze
dd Zdd Zdd Zedd Zdd  Zdef fd!d"Zd#d$ Zd%d& Zd'd( Zd)d* Zd2d+d,Zd3d-d.Z d/d0 Z!dS )4ForeignObjectRelz
    Used by ForeignObject to store information about the relation.

    ``_meta.get_fields()`` returns this class to provide access to the field
    flags for the reverse relation.
    TFNc             C   sF   || _ || _|| _|| _|d kr$i n|| _|| _|| _d| _d| _d S )NFT)	fieldmodelrelated_namerelated_query_namelimit_choices_toparent_link	on_deletesymmetricalmultiple)selfr   tor
   r   r   r   r    r   I/tmp/pip-build-8app2_gc/Django/django/db/models/fields/reverse_related.py__init__%   s    zForeignObjectRel.__init__c             C   s   | j  S )N)	is_hidden)r   r   r   r   hidden6   s    zForeignObjectRel.hiddenc             C   s
   | j j S )N)r   r   )r   r   r   r   name:   s    zForeignObjectRel.namec             C   s   | j S )N)r   )r   r   r   r   remote_field>   s    zForeignObjectRel.remote_fieldc             C   s,   | j  d j}t|dkr$tjd|d S )z
        When filtering against this relation, return the field on the remote
        model against which the filtering should happen.
        r   z1Can't use target_field for multicolumn relations.r   )get_path_infotarget_fieldslenr   Z
FieldError)r   r   r   r   r   target_fieldB   s    
zForeignObjectRel.target_fieldc             C   s   | j jstd| j jS )NzVThis property can't be accessed before self.field.contribute_to_class has been called.)r   r	   AttributeError)r   r   r   r   related_modelM   s    zForeignObjectRel.related_modelc             C   s   | j jS )N)r   many_to_many)r   r   r   r   r!   T   s    zForeignObjectRel.many_to_manyc             C   s   | j jS )N)r   one_to_many)r   r   r   r   many_to_oneX   s    zForeignObjectRel.many_to_onec             C   s   | j jS )N)r   r#   )r   r   r   r   r"   \   s    zForeignObjectRel.one_to_manyc             C   s   | j jS )N)r   
one_to_one)r   r   r   r   r$   `   s    zForeignObjectRel.one_to_onec             C   s   | j j|S )N)r   
get_lookup)r   lookup_namer   r   r   r%   d   s    zForeignObjectRel.get_lookupc             C   s
   | j j S )N)r   get_internal_type)r   r   r   r   r'   g   s    z"ForeignObjectRel.get_internal_typec             C   s   | j jS )N)r   db_type)r   r   r   r   r(   j   s    zForeignObjectRel.db_typec             C   s    dt | j| jjj| jjjf S )Nz<%s: %s.%s>)type__name__r    _metaZ	app_label
model_name)r   r   r   r   __repr__n   s    zForeignObjectRel.__repr__c             C   s$   |r|ng dd | j jj| D  S )a  
        Return choices with a default blank choices included, for use
        as <select> choices for this field.

        Analog of django.db.models.fields.Field.get_choices(), provided
        initially for utilization by RelatedFieldListFilter.
        c             S   s   g | ]}|j t|fqS r   )pkstr).0xr   r   r   
<listcomp>~   s    z0ForeignObjectRel.get_choices.<locals>.<listcomp>)r    Z_default_managerZorder_by)r   Zinclude_blankZblank_choiceZorderingr   r   r   get_choicesu   s    
zForeignObjectRel.get_choicesc             C   s   t | jo| jd dkS )z$Should the related object be hidden?r   +r   )boolr
   )r   r   r   r   r      s    zForeignObjectRel.is_hiddenc             C   s
   | j j S )N)r   Zget_reverse_joining_columns)r   r   r   r   get_joining_columns   s    z$ForeignObjectRel.get_joining_columnsc             C   s   | j j|||S )N)r   get_extra_restriction)r   Zwhere_classaliasZrelated_aliasr   r   r   r7      s    z&ForeignObjectRel.get_extra_restrictionc             C   s
   d| _ dS )z
        Set the related field's name, this is not available until later stages
        of app loading, so set_field_name is called from
        set_attributes_from_rel()
        N)
field_name)r   r   r   r   set_field_name   s    zForeignObjectRel.set_field_namec             C   sV   |r
|j n| jj }|p| j}| jr6| jr6|| jkr6d S | jrB| jS |j| jrPdnd S )NZ_set )r+   r    r   r   r	   r
   r,   )r   r	   optsr   r   r   get_accessor_name   s    
z"ForeignObjectRel.get_accessor_namec             C   s   | j j|S )N)r   Zget_reverse_path_info)r   Zfiltered_relationr   r   r   r      s    zForeignObjectRel.get_path_infoc             C   s   | j  S )z
        Return the name of the cache key to use for storing an instance of the
        forward model on the reverse model.
        )r=   )r   r   r   r   get_cache_name   s    zForeignObjectRel.get_cache_name)NNNFN)N)N)"r*   
__module____qualname____doc__Zauto_createdconcreteeditableZis_relationnullr   r   r   r   propertyr   r   r    r!   r#   r"   r$   r%   r'   r(   r-   r   r3   r   r6   r7   r:   r=   r   r>   r   r   r   r   r      s:    



r   c                   s:   e Zd ZdZd fdd	Zdd Zdd	 Zd
d Z  ZS )ManyToOneRela+  
    Used by the ForeignKey field to store information about the relation.

    ``_meta.get_fields()`` returns this class to provide access to the field
    flags for the reverse relation.

    Note: Because we somewhat abuse the Rel objects by using them as reverse
    fields we get the funny situation where
    ``ManyToOneRel.many_to_one == False`` and
    ``ManyToOneRel.one_to_many == True``. This is unfortunate but the actual
    ManyToOneRel class is a private API and there is work underway to turn
    reverse relations into actual fields.
    NFc	       	   	      s$   t  j|||||||d || _d S )N)r
   r   r   r   r   )superr   r9   )	r   r   r   r9   r
   r   r   r   r   )	__class__r   r   r      s    zManyToOneRel.__init__c             C   s   | j j }|jdd  |S )Nr    )__dict__copypop)r   stater   r   r   __getstate__   s    
zManyToOneRel.__getstate__c             C   s*   | j jj| j}|js&tjd| j |S )zY
        Return the Field in the 'to' object to which this relationship is tied.
        zNo related field named '%s')r	   r+   	get_fieldr9   rB   r   ZFieldDoesNotExist)r   r   r   r   r   get_related_field   s    zManyToOneRel.get_related_fieldc             C   s   | j p| jjjj| _ d S )N)r9   r	   r+   r.   r   )r   r   r   r   r:      s    zManyToOneRel.set_field_name)NNNFN)	r*   r?   r@   rA   r   rM   rO   r:   __classcell__r   r   )rH   r   rF      s    	rF   c                   s"   e Zd ZdZd fdd	Z  ZS )OneToOneRelz
    Used by OneToOneField to store information about the relation.

    ``_meta.get_fields()`` returns this class to provide access to the field
    flags for the reverse relation.
    NFc	       	   
      s&   t  j||||||||d d| _d S )N)r
   r   r   r   r   F)rG   r   r   )	r   r   r   r9   r
   r   r   r   r   )rH   r   r   r      s    zOneToOneRel.__init__)NNNFN)r*   r?   r@   rA   r   rP   r   r   )rH   r   rQ      s    rQ   c                   s*   e Zd ZdZd fdd	Zdd Z  ZS )	ManyToManyRelz
    Used by ManyToManyField to store information about the relation.

    ``_meta.get_fields()`` returns this class to provide access to the field
    flags for the reverse relation.
    NTc
       
         sV   t  j|||||d |r(|	 r(td|| _|r@| r@td|| _|| _|	| _d S )N)r
   r   r   z4Can't supply a through model and db_constraint=Falsez5Cannot specify through_fields without a through model)rG   r   
ValueErrorthroughthrough_fieldsr   db_constraint)
r   r   r   r
   r   r   r   rT   rU   rV   )rH   r   r   r      s    

zManyToManyRel.__init__c             C   sX   | j j}| jr |j| jd }n.x,|jD ]"}t|dd}|r(|j| jkr(P q(W |jd S )z
        Return the field in the 'to' object to which this relationship is tied.
        Provided for symmetry with ManyToOneRel.
        r   r   N)rT   r+   rU   rN   fieldsgetattrr	   Zforeign_related_fields)r   r<   r   relr   r   r   rO     s    zManyToManyRel.get_related_field)NNNTNNT)r*   r?   r@   rA   r   rO   rP   r   r   )rH   r   rR      s
     rR   N)rA   Zdjango.corer   Zdjango.utils.functionalr   r;   r   Zmixinsr   r   rF   rQ   rR   r   r   r   r   <module>
   s    .