
v^'                 @   s   d  Z  d d l m Z d d l m Z d d l m Z d d l m Z Gd d   d e  Z	 Gd	 d
   d
 e	  Z
 Gd d   d e
  Z Gd 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 d d d d d 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 e
 d d    Z d d   Z d d   Z e d d    Z d d    Z d e f  d! d"  Z d# d$   Z d% d&   Z d' d(   Z d) d*   Z d d+ d,  Z d d- d.  Z  d/ d0   Z! d S)1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   sg   | |  _  | |  _ | |  _ | |  _ | d  k r6 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-8lau8j11/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 r4 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   sH   |  j  j j   } | r' | j |   } | r3 | n g  d d   | 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 Sr   )pkstr).0xr   r   r   
<listcomp>   s   	 z0ForeignObjectRel.get_choices.<locals>.<listcomp>)r    Z_default_managerallZorder_by)r   Zinclude_blankZblank_choiceZorderingqsr   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   r9      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   sy   | r | j  n	 |  j j  } | p' |  j } |  j rO |  j rO | |  j k rO d  S|  j r_ |  j S| j |  j rt d 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)"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   r5   r   r8   r9   r<   r?   r   r@   r   r   r   r   r      s:   
r   c                   s[   e  Z d  Z d Z d d d d d   f d d  Z d d   Z d d	   Z d
 d   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 | d | d | d | | |  _ d  S)Nr
   r   r   r   r   )superr   r;   )	r   r   r   r;   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 s7 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_fieldr;   rD   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)r;   r	   r+   r.   r   )r   r   r   r   r<      s    zManyToOneRel.set_field_name)r*   rA   rB   rC   r   rO   rQ   r<   r   r   )rJ   r   rH      s   	rH   c                   s7   e  Z d  Z d Z d d d d d   f d d  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	       	         sA   t    j | | | d | d | d | d | d | d |  _ d  S)Nr
   r   r   r   r   F)rI   r   r   )	r   r   r   r;   r
   r   r   r   r   )rJ   r   r   r      s    	zOneToOneRel.__init__)r*   rA   rB   rC   r   r   r   )rJ   r   rR      s   rR   c            
       sI   e  Z d  Z d Z d d d d d d d   f d d  Z d d   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
       
   	      s   t    j | | d | d | d | | r> |	 r> t d   | |  _ | r` | r` t d   | |  _ | |  _ |	 |  _ d  S)Nr
   r   r   z4Can't supply a through model and db_constraint=Falsez5Cannot specify through_fields without a through model)rI   r   
ValueErrorthroughthrough_fieldsr   db_constraint)
r   r   r   r
   r   r   r   rU   rV   rW   )rJ   r   r   r      s    					zManyToManyRel.__init__c             C   sx   |  j  j } |  j r. | j |  j d  } n? x< | j D]1 } t | d d  } | r8 | j |  j k r8 Pq8 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)rU   r+   rV   rP   fieldsgetattrr	   Zforeign_related_fields)r   r>   r   relr   r   r   rQ     s    	zManyToManyRel.get_related_field)r*   rA   rB   rC   r   rQ   r   r   )rJ   r   rS      s
   	rS   N)rC   Zdjango.corer   Zdjango.utils.functionalr   r=   r   Zmixinsr   r   rH   rR   rS   r   r   r   r   <module>
   s   .