B
    CVvgÊ+  ã               @   s„   d Z ddlm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
ƒZG d
d„ deƒZG dd„ deƒZG dd„ deƒ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.
é    )Ú
exceptions)Úcached_property)Úmake_hashableé   )ÚBLANK_CHOICE_DASH)ÚFieldCacheMixinc               @   s,  e Zd ZdZdZdZdZdZdZdZ	d8dd„Z
edd„ ƒZed	d
„ ƒZedd„ ƒZedd„ ƒZedd„ ƒZedd„ ƒZedd„ ƒZedd„ ƒZedd„ ƒZdd„ Zdd„ Zedd„ ƒZdd „ Zed!d"„ ƒZd#d$„ Zd%d&„ Zdedd'fd(d)„Zd*d+„ Zd,d-„ Z d.d/„ Z!d0d1„ Z"d9d2d3„Z#d:d4d5„Z$d6d7„ Z%dS );ÚForeignObjectRelzº
    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$i n|| _|| _|| _d| _d| _d S )NFT)	ÚfieldÚmodelÚrelated_nameÚrelated_query_nameÚlimit_choices_toÚparent_linkÚ	on_deleteÚsymmetricalÚmultiple)Úselfr	   Útor   r   r   r   r   © r   úK/tmp/pip-install-o3oxmrkh/Django/django/db/models/fields/reverse_related.pyÚ__init__'   s    zForeignObjectRel.__init__c             C   s   |   ¡ S )N)Ú	is_hidden)r   r   r   r   Úhidden8   s    zForeignObjectRel.hiddenc             C   s
   | j  ¡ S )N)r	   r   )r   r   r   r   Úname<   s    zForeignObjectRel.namec             C   s   | j S )N)r	   )r   r   r   r   Úremote_field@   s    zForeignObjectRel.remote_fieldc             C   s,   |   ¡ d j}t|ƒdkr$t d¡‚|d S )z�
        When filtering against this relation, return the field on the remote
        model against which the filtering should happen.
        éÿÿÿÿr   z1Can't use target_field for multicolumn relations.r   )Úget_path_infoÚtarget_fieldsÚlenr   Z
FieldError)r   r   r   r   r   Útarget_fieldD   s    
zForeignObjectRel.target_fieldc             C   s   | j jstdƒ‚| j jS )NzVThis property can't be accessed before self.field.contribute_to_class has been called.)r	   r
   ÚAttributeError)r   r   r   r   Úrelated_modelO   s    zForeignObjectRel.related_modelc             C   s   | j jS )N)r	   Úmany_to_many)r   r   r   r   r"   V   s    zForeignObjectRel.many_to_manyc             C   s   | j jS )N)r	   Úone_to_many)r   r   r   r   Úmany_to_oneZ   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	   Ú
one_to_one)r   r   r   r   r%   b   s    zForeignObjectRel.one_to_onec             C   s   | j  |¡S )N)r	   Ú
get_lookup)r   Úlookup_namer   r   r   r&   f   s    zForeignObjectRel.get_lookupc             C   s
   | j  ¡ S )N)r	   Úget_internal_type)r   r   r   r   r(   i   s    z"ForeignObjectRel.get_internal_typec             C   s   | j jS )N)r	   Údb_type)r   r   r   r   r)   l   s    zForeignObjectRel.db_typec             C   s    dt | ƒj| jjj| jjjf S )Nz<%s: %s.%s>)ÚtypeÚ__name__r!   Ú_metaZ	app_labelÚ
model_name)r   r   r   r   Ú__repr__p   s    zForeignObjectRel.__repr__c          	   C   s,   | j | j| j| jt| jƒ| j| j| j| j	f	S )N)
r	   r
   r   r   r   r   r   r   r   r   )r   r   r   r   Úidentityw   s    zForeignObjectRel.identityc             C   s   t || jƒstS | j|jkS )N)Ú
isinstanceÚ	__class__ÚNotImplementedr/   )r   Úotherr   r   r   Ú__eq__…   s    zForeignObjectRel.__eq__c             C   s
   t | jƒS )N)Úhashr/   )r   r   r   r   Ú__hash__Š   s    zForeignObjectRel.__hash__r   c             C   s@   |p| j }| jj |¡}|r&|j|Ž }|r.|ng dd„ |D ƒ 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|ƒf‘qS r   )ÚpkÚstr)Ú.0Úxr   r   r   ú
<listcomp>�   s    z0ForeignObjectRel.get_choices.<locals>.<listcomp>)r   r!   Z_default_managerZcomplex_filterZorder_by)r   Zinclude_blankZblank_choicer   ZorderingÚqsr   r   r   Úget_choices�   s    


zForeignObjectRel.get_choicesc             C   s   t | jƒo| jd dkS )z$Should the related object be hidden?r   ú+)Úboolr   )r   r   r   r   r       s    zForeignObjectRel.is_hiddenc             C   s
   | j  ¡ S )N)r	   Zget_reverse_joining_columns)r   r   r   r   Úget_joining_columns¤   s    z$ForeignObjectRel.get_joining_columnsc             C   s   | j  |||¡S )N)r	   Úget_extra_restriction)r   Zwhere_classÚaliasZrelated_aliasr   r   r   rA   §   s    z&ForeignObjectRel.get_extra_restrictionc             C   s
   d| _ dS )z³
        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)Ú
field_name)r   r   r   r   Úset_field_nameª   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_setÚ )r,   r!   r   r   r
   r   r-   )r   r
   Úoptsr   r   r   Úget_accessor_name´   s    
z"ForeignObjectRel.get_accessor_namec             C   s   | j  |¡S )N)r	   Zget_reverse_path_info)r   Zfiltered_relationr   r   r   r   Å   s    zForeignObjectRel.get_path_infoc             C   s   |   ¡ S )z„
        Return the name of the cache key to use for storing an instance of the
        forward model on the reverse model.
        )rG   )r   r   r   r   Úget_cache_nameÈ   s    zForeignObjectRel.get_cache_name)NNNFN)N)N)&r+   Ú
__module__Ú__qualname__Ú__doc__Zauto_createdÚconcreteÚeditableZis_relationÚnullZempty_strings_allowedr   r   r   r   Úpropertyr   r   r!   r"   r$   r#   r%   r&   r(   r)   r.   r/   r4   r6   r   r=   r   r@   rA   rD   rG   r   rH   r   r   r   r   r      sD    



r   c                   sJ   e Zd ZdZd‡ fdd„	Zdd„ Ze‡ fdd	„ƒZd
d„ Zdd„ Z	‡  Z
S )Ú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 ƒ j|||||||d� || _d S )N)r   r   r   r   r   )Úsuperr   rC   )	r   r	   r   rC   r   r   r   r   r   )r1   r   r   r   ß   s    zManyToOneRel.__init__c             C   s   | j  ¡ }| dd ¡ |S )Nr!   )Ú__dict__ÚcopyÚpop)r   Ústater   r   r   Ú__getstate__ì   s    
zManyToOneRel.__getstate__c                s   t ƒ j| jf S )N)rQ   r/   rC   )r   )r1   r   r   r/   ñ   s    zManyToOneRel.identityc             C   s*   | j j | j¡}|js&t 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,   Ú	get_fieldrC   rL   r   ZFieldDoesNotExist)r   r	   r   r   r   Úget_related_fieldõ   s    zManyToOneRel.get_related_fieldc             C   s   | j p| jjjj| _ d S )N)rC   r
   r,   r7   r   )r   r   r   r   rD   þ   s    zManyToOneRel.set_field_name)NNNFN)r+   rI   rJ   rK   r   rV   rO   r/   rX   rD   Ú__classcell__r   r   )r1   r   rP   Ð   s    	rP   c                   s"   e Zd ZdZd‡ fdd„	Z‡  ZS )ÚOneToOneRelzº
    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 ƒ j||||||||d� d| _d S )N)r   r   r   r   r   F)rQ   r   r   )	r   r	   r   rC   r   r   r   r   r   )r1   r   r   r   
  s    zOneToOneRel.__init__)NNNFN)r+   rI   rJ   rK   r   rY   r   r   )r1   r   rZ     s    rZ   c                   s:   e Zd ZdZd
‡ fdd„	Ze‡ fdd„ƒZdd	„ Z‡  ZS )ÚManyToManyRelz¼
    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
       
         sR   t ƒ j|||||d� |r&|	s&tdƒ‚|| _|r<|s<tdƒ‚|| _|| _|	| _d S )N)r   r   r   z4Can't supply a through model and db_constraint=Falsez5Cannot specify through_fields without a through model)rQ   r   Ú
ValueErrorÚthroughÚthrough_fieldsr   Údb_constraint)
r   r	   r   r   r   r   r   r]   r^   r_   )r1   r   r   r      s    zManyToManyRel.__init__c                s   t ƒ j| jt| jƒ| jf S )N)rQ   r/   r]   r   r^   r_   )r   )r1   r   r   r/   5  s    zManyToManyRel.identityc             C   sX   | j j}| jr | | jd ¡}n.x,|jD ]"}t|ddƒ}|r(|j| jkr(P q(W |jd S )zŠ
        Return the field in the 'to' object to which this relationship is tied.
        Provided for symmetry with ManyToOneRel.
        r   r   N)r]   r,   r^   rW   ÚfieldsÚgetattrr
   Zforeign_related_fields)r   rF   r	   Úrelr   r   r   rX   =  s    zManyToManyRel.get_related_field)NNNTNNT)	r+   rI   rJ   rK   r   rO   r/   rX   rY   r   r   )r1   r   r[     s     r[   N)rK   Zdjango.corer   Zdjango.utils.functionalr   Zdjango.utils.hashabler   rE   r   Zmixinsr   r   rP   rZ   r[   r   r   r   r   Ú<module>
   s    =2