B
    CVvg                 @   s   d Z ddlmZ G dd d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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 )z~
Helpers to manipulate deferred DDL statements that might need to be adjusted or
discarded within when executing a migration.
    )deepcopyc               @   s@   e Zd ZdZdd Zdd Zdd Zdd	 Zd
d Zdd Z	dS )	Referencez0Base class that defines the reference interface.c             C   s   dS )zU
        Return whether or not this instance references the specified table.
        F )selftabler   r   E/tmp/pip-install-o3oxmrkh/Django/django/db/backends/ddl_references.pyreferences_table   s    zReference.references_tablec             C   s   dS )zV
        Return whether or not this instance references the specified column.
        Fr   )r   r   columnr   r   r   references_column   s    zReference.references_columnc             C   s   dS )zI
        Rename all references to the old_name to the new_table.
        Nr   )r   	old_table	new_tabler   r   r   rename_table_references   s    z!Reference.rename_table_referencesc             C   s   dS )zL
        Rename all references to the old_column to the new_column.
        Nr   )r   r   
old_column
new_columnr   r   r   rename_column_references   s    z"Reference.rename_column_referencesc             C   s   d| j jt| f S )Nz<%s %r>)	__class____name__str)r   r   r   r   __repr__#   s    zReference.__repr__c             C   s   t dd S )Nz>Subclasses must define how they should be converted to string.)NotImplementedError)r   r   r   r   __str__&   s    zReference.__str__N)
r   
__module____qualname____doc__r   r
   r   r   r   r   r   r   r   r   r      s   r   c               @   s0   e Zd ZdZdd Zdd Zdd Zdd	 Zd
S )TablezHold a reference to a table.c             C   s   || _ || _d S )N)r   
quote_name)r   r   r   r   r   r   __init__-   s    zTable.__init__c             C   s
   | j |kS )N)r   )r   r   r   r   r   r   1   s    zTable.references_tablec             C   s   | j |kr|| _ d S )N)r   )r   r   r   r   r   r   r   4   s    
zTable.rename_table_referencesc             C   s   |  | jS )N)r   r   )r   r   r   r   r   8   s    zTable.__str__N)r   r   r   r   r   r   r   r   r   r   r   r   r   *   s
   r   c               @   s(   e Zd ZdZdd Zdd Zdd ZdS )	TableColumnsz9Base class for references to multiple columns of a table.c             C   s   || _ || _d S )N)r   columns)r   r   r   r   r   r   r   ?   s    zTableColumns.__init__c             C   s   | j |ko|| jkS )N)r   r   )r   r   r	   r   r   r   r
   C   s    zTableColumns.references_columnc             C   s8   | j |kr4x(t| jD ]\}}||kr|| j|< qW d S )N)r   	enumerater   )r   r   r   r   indexr	   r   r   r   r   F   s    
z%TableColumns.rename_column_referencesN)r   r   r   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  ZS )Columnsz(Hold a reference to one or many columns.r   c                s   || _ || _t || d S )N)r   col_suffixessuperr   )r   r   r   r   r"   )r   r   r   r   P   s    zColumns.__init__c                s*   fdd d  fddtjD S )Nc                sB     | }y j| }|r&d||}W n tk
r<   Y nX |S )Nz{} {})r   r"   format
IndexError)r	   idxcolsuffix)r   r   r   col_strV   s    

z Columns.__str__.<locals>.col_strz, c             3   s   | ]\}} ||V  qd S )Nr   ).0r&   r	   )r)   r   r   	<genexpr>`   s    z"Columns.__str__.<locals>.<genexpr>)joinr   r   )r   r   )r)   r   r   r   U   s    
zColumns.__str__)r   )r   r   r   r   r   r   __classcell__r   r   )r   r   r!   M   s   r!   c                   s(   e Zd ZdZ fddZdd Z  ZS )	IndexNamez"Hold a reference to an index name.c                s   || _ || _t || d S )N)r(   create_index_namer#   r   )r   r   r   r(   r/   )r   r   r   r   f   s    zIndexName.__init__c             C   s   |  | j| j| jS )N)r/   r   r   r(   )r   r   r   r   r   k   s    zIndexName.__str__)r   r   r   r   r   r   r-   r   r   )r   r   r.   c   s   r.   c                   s&   e Zd Zd fdd	Zdd Z  ZS )IndexColumnsr   c                s   || _ t |||| d S )N)	opclassesr#   r   )r   r   r   r   r"   r1   )r   r   r   r   p   s    zIndexColumns.__init__c                s*   fdd d  fddtjD S )Nc                sP   d  |  j| }y j| }|r4d ||}W n tk
rJ   Y nX |S )Nz{} {})r$   r   r1   r"   r%   )r	   r&   r'   r(   )r   r   r   r)   u   s    
z%IndexColumns.__str__.<locals>.col_strz, c             3   s   | ]\}} ||V  qd S )Nr   )r*   r&   r	   )r)   r   r   r+      s    z'IndexColumns.__str__.<locals>.<genexpr>)r,   r   r   )r   r   )r)   r   r   r   t   s    zIndexColumns.__str__)r   r   )r   r   r   r   r   r-   r   r   )r   r   r0   o   s   r0   c                   sX   e Zd ZdZ fddZ fddZ fddZ fdd	Z fd
dZdd Z	  Z
S )ForeignKeyNamez'Hold a reference to a foreign key name.c                s*   t ||| _|| _|| _t || d S )N)r   to_referencesuffix_templatecreate_fk_namer#   r   )r   Z
from_tableZfrom_columnsto_tableZ
to_columnsr4   r5   )r   r   r   r      s    zForeignKeyName.__init__c                s   t  |p| j|S )N)r#   r   r3   )r   r   )r   r   r   r      s    zForeignKeyName.references_tablec                s   t  ||p| j||S )N)r#   r
   r3   )r   r   r	   )r   r   r   r
      s    z ForeignKeyName.references_columnc                s    t  || | j|| d S )N)r#   r   r3   )r   r   r   )r   r   r   r      s    z&ForeignKeyName.rename_table_referencesc                s$   t  ||| | j||| d S )N)r#   r   r3   )r   r   r   r   )r   r   r   r      s    z'ForeignKeyName.rename_column_referencesc             C   s.   | j | jj| jjd d }| | j| j|S )Nr   )r6   Z	to_column)r4   r3   r   r   r5   )r   r(   r   r   r   r      s    zForeignKeyName.__str__)r   r   r   r   r   r   r
   r   r   r   r-   r   r   )r   r   r2      s   r2   c               @   s@   e Zd ZdZdd Zdd Zdd Zdd	 Zd
d Zdd Z	dS )	Statementz
    Statement template and formatting parameters container.

    Allows keeping a reference to a statement without interpolating identifiers
    that might have to be adjusted if they're referencing a table or column
    that is removed
    c             K   s   || _ || _d S )N)templateparts)r   r8   r9   r   r   r   r      s    zStatement.__init__c                s   t  fdd| j D S )Nc             3   s"   | ]}t |d o| V  qdS )r   N)hasattrr   )r*   part)r   r   r   r+      s   z-Statement.references_table.<locals>.<genexpr>)anyr9   values)r   r   r   )r   r   r      s    
zStatement.references_tablec                s   t  fdd| j D S )Nc             3   s$   | ]}t |d o| V  qdS )r
   N)r:   r
   )r*   r;   )r	   r   r   r   r+      s   z.Statement.references_column.<locals>.<genexpr>)r<   r9   r=   )r   r   r	   r   )r	   r   r   r
      s    zStatement.references_columnc             C   s.   x(| j  D ]}t|dr||| qW d S )Nr   )r9   r=   r:   r   )r   r   r   r;   r   r   r   r      s    
z!Statement.rename_table_referencesc             C   s0   x*| j  D ]}t|dr|||| qW d S )Nr   )r9   r=   r:   r   )r   r   r   r   r;   r   r   r   r      s    
z"Statement.rename_column_referencesc             C   s   | j | j S )N)r8   r9   )r   r   r   r   r      s    zStatement.__str__N)
r   r   r   r   r   r   r
   r   r   r   r   r   r   r   r7      s   r7   c                   s8   e Zd Z fddZ fddZdd Zdd Z  ZS )	Expressionsc                s@   || _ || _|| _dd | j j| jgD }t || d S )Nc             S   s   g | ]}|j jqS r   )targetr	   )r*   r'   r   r   r   
<listcomp>   s    z(Expressions.__init__.<locals>.<listcomp>)compilerexpressionsquote_valuequery	_gen_colsr#   r   )r   r   rB   rA   rC   r   )r   r   r   r      s
    zExpressions.__init__c                s2   | j |krd S | j||i| _t || d S )N)r   rB   Zrelabeled_cloner#   r   )r   r   r   )r   r   r   r      s    
z#Expressions.rename_table_referencesc             C   sf   | j |krd S t| j}g | _x<| jj|gD ](}|jj|krH||j_| j	|jj q0W || _d S )N)
r   r   rB   r   rA   rD   rE   r?   r	   append)r   r   r   r   rB   r'   r   r   r   r      s    

z$Expressions.rename_column_referencesc             C   s*   | j | j\}}t| j|}|t| S )N)rA   compilerB   maprC   tuple)r   Zsqlparamsr   r   r   r      s    zExpressions.__str__)r   r   r   r   r   r   r   r-   r   r   )r   r   r>      s   r>   N)r   copyr   r   r   r   r!   r.   r0   r2   r7   r>   r   r   r   r   <module>   s   ""&