U
    8ÄT_G(  ã                   @   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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_propertyé   )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	d2d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dedd!fd"d#„Zd$d%„ Zd&d'„ Zd(d)„ Zd*d+„ Zd3d,d-„Z d4d.d/„Z!d0d1„ Z"dS )5Ú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$i n|| _|| _|| _d| _d| _d S )NFT)	ÚfieldÚmodelÚrelated_nameÚrelated_query_nameÚlimit_choices_toÚparent_linkÚ	on_deleteÚsymmetricalÚmultiple)Úselfr   Útor
   r   r   r   r   © r   úK/tmp/pip-unpacked-wheel-dv63caxw/django/db/models/fields/reverse_related.pyÚ__init__&   s    zForeignObjectRel.__init__c                 C   s   |   ¡ S ©N)Ú	is_hidden©r   r   r   r   Úhidden7   s    zForeignObjectRel.hiddenc                 C   s
   | j  ¡ S r   )r   r   r   r   r   r   Úname;   s    zForeignObjectRel.namec                 C   s   | j S r   )r   r   r   r   r   Úremote_field?   s    zForeignObjectRel.remote_fieldc                 C   s,   |   ¡ d j}t|ƒdkr$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_fieldC   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AttributeErrorr   r   r   r   Úrelated_modelN   s
    ÿzForeignObjectRel.related_modelc                 C   s   | j jS r   )r   Úmany_to_manyr   r   r   r   r#   U   s    zForeignObjectRel.many_to_manyc                 C   s   | j jS r   )r   Úone_to_manyr   r   r   r   Úmany_to_oneY   s    zForeignObjectRel.many_to_onec                 C   s   | j jS r   )r   r%   r   r   r   r   r$   ]   s    zForeignObjectRel.one_to_manyc                 C   s   | j jS r   )r   Ú
one_to_oner   r   r   r   r&   a   s    zForeignObjectRel.one_to_onec                 C   s   | j  |¡S r   )r   Ú
get_lookup)r   Úlookup_namer   r   r   r'   e   s    zForeignObjectRel.get_lookupc                 C   s
   | j  ¡ S r   )r   Úget_internal_typer   r   r   r   r)   h   s    z"ForeignObjectRel.get_internal_typec                 C   s   | j jS r   )r   Údb_typer   r   r   r   r*   k   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_namer   r   r   r   Ú__repr__o   s
    ýzForeignObjectRel.__repr__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_choicesv   s    

ÿzForeignObjectRel.get_choicesc                 C   s   t | jƒo| jd dkS )z$Should the related object be hidden?r   ú+)Úboolr
   r   r   r   r   r   ‰   s    zForeignObjectRel.is_hiddenc                 C   s
   | j  ¡ S r   )r   Zget_reverse_joining_columnsr   r   r   r   Úget_joining_columns�   s    z$ForeignObjectRel.get_joining_columnsc                 C   s   | j  |||¡S r   )r   Úget_extra_restriction)r   Zwhere_classÚaliasZrelated_aliasr   r   r   r:   �   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_namer   r   r   r   Ú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_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 r   )r   Zget_reverse_path_info)r   Zfiltered_relationr   r   r   r   ®   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.
        )r@   r   r   r   r   Úget_cache_name±   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   r6   r   r9   r:   r=   r@   r   rA   r   r   r   r   r      s^         ÿ











  þ



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 )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   r<   ©	r   r   r   r<   r
   r   r   r   r   ©Ú	__class__r   r   r   È   s     ú	zManyToOneRel.__init__c                 C   s   | j  ¡ }| dd ¡ |S )Nr"   )Ú__dict__ÚcopyÚpop)r   Ústater   r   r   Ú__getstate__Õ   s    
zManyToOneRel.__getstate__c                 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_fieldr<   rE   r   ZFieldDoesNotExist)r   r   r   r   r   Úget_related_fieldÚ   s    zManyToOneRel.get_related_fieldc                 C   s   | j p| jjjj| _ d S r   )r<   r	   r-   r0   r   r   r   r   r   r=   ã   s    zManyToOneRel.set_field_name)NNNFN)	r,   rB   rC   rD   r   rS   rU   r=   Ú__classcell__r   r   rM   r   rI   ¹   s         ÿ	rI   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 )NrJ   F)rK   r   r   rL   rM   r   r   r   ï   s      ú	zOneToOneRel.__init__)NNNFN)r,   rB   rC   rD   r   rV   r   r   rM   r   rW   ç   s         ÿrW   c                       s*   e Zd ZdZd‡ fdd„	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)rK   r   Ú
ValueErrorÚthroughÚthrough_fieldsr   Údb_constraint)
r   r   r   r
   r   r   r   rZ   r[   r\   rM   r   r   r     s     üzManyToManyRel.__init__c                 C   sV   | j j}| jr | | jd ¡}n,|jD ]$}t|ddƒ}|r&|j| jkr& qLq&|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)rZ   r-   r[   rT   ÚfieldsÚgetattrr	   Zforeign_related_fields)r   r?   r   Úrelr   r   r   rU     s    
zManyToManyRel.get_related_field)NNNTNNT)r,   rB   rC   rD   r   rU   rV   r   r   rM   r   rX   ý   s            þrX   N)rD   Zdjango.corer   Zdjango.utils.functionalr   r>   r   Zmixinsr   r   rI   rW   rX   r   r   r   r   Ú<module>   s    '.