

_V=                 @   s   d  d l  m Z d  d l m Z m Z m Z m Z m Z m Z m	 Z	 m
 Z
 m Z m Z m Z d  d l m Z Gd d   d e  Z d S)    )unicode_literals)AddField
AlterFieldAlterIndexTogetherAlterModelTableAlterOrderWithRespectToAlterUniqueTogetherCreateModelDeleteModelRemoveFieldRenameFieldRenameModel)sixc               @   s6  e  Z d  Z d Z d d   Z d d d  Z d d d  Z d d	 d
  Z d d   Z d d   Z	 d d   Z
 d d   Z d d   Z d d   Z d d   Z d d   Z d d   Z d d   Z d d    Z d! d"   Z d# d$   Z d% d&   Z d' d(   Z d) d*   Z d+ d,   Z d- d.   Z d d/ d0  Z d S)1MigrationOptimizera^  
    Powers the optimization process, where you provide a list of Operations
    and you are returned a list of equal or shorter length - operations
    are merged into one if possible.

    For example, a CreateModel and an AddField can be optimized into a
    new CreateModel, and CreateModel and DeleteModel can be optimized into
    nothing.
    c             C   sD  t  t t t t f |  _ t t f |  _ i! |  j	 t  t
 f 6|  j t  t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t
 f 6|  j t t
 f 6|  j t t
 f 6|  j t t
 f 6|  j t  t f 6|  j t  t f 6|  j t  t f 6|  j t  t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  j t t f 6|  _ d  S)N)r	   r   r   r   r   model_level_operationsr   r   field_level_operations reduce_create_model_delete_modelr
    reduce_create_model_rename_modelr    reduce_rename_model_rename_modelreduce_alter_model_alter_modelreduce_alter_model_delete_modelreduce_create_model_add_fieldreduce_create_model_alter_field reduce_create_model_remove_fieldr    reduce_create_model_rename_fieldr   'reduce_alter_model_addalterremove_fieldreduce_alter_model_rename_fieldreduce_add_field_alter_fieldreduce_add_field_remove_fieldreduce_add_field_rename_fieldreduce_alter_field_remove_fieldreduce_alter_field_rename_field reduce_rename_field_rename_fieldreduce_methods)self r%   @/tmp/pip-build-ghmbqnp_/Django/django/db/migrations/optimizer.py__init__   sR    zMigrationOptimizer.__init__Nc             C   sK   d |  _  x; |  j | |  } |  j  d 7_  | | k r= | S| } q Wd S)a  
        Main optimization entry point. Pass in a list of Operation instances,
        get out a new list of Operation instances.

        Unfortunately, due to the scope of the optimization (two combinable
        operations might be separated by several hundred others), this can't be
        done as a peephole optimization with checks/output implemented on
        the Operations themselves; instead, the optimizer looks at each
        individual operation and scans forwards in the list to see if there
        are any matches, stopping at boundaries - operations which can't
        be optimized over (RunSQL, operations on the same field/model, etc.)

        The inner loop is run until the starting list is the same as the result
        list, and then the result is returned. This means that operation
        optimization must be stable and always return an equal or shorter list.

        The app_label argument is optional, but if you pass it you'll get more
        efficient optimization.
        r      N)Z_iterationsoptimize_inner)r$   
operations	app_labelresultr%   r%   r&   optimizeO   s    	zMigrationOptimizer.optimizec       	   	   C   s  g  } xt  |  D] \ } } x t  | | d d   D] \ } } |  j | | | | d | | d   } | d k	 r | j |  | j | | d | d |   | j | | | d d   | S|  j | | |  s: | j |  Pq: q: W| j |  q W| S)z*
        Inner optimization loop.
        r(   N   )	enumeratereduceextendcan_optimize_throughappend)	r$   r*   r+   Znew_operationsi	operationjotherr,   r%   r%   r&   r)   l   s    '+#z!MigrationOptimizer.optimize_innerc             C   sD   |  j  j t |  t |  f  } | r@ | | | | p< g   Sd S)z
        Either returns a list of zero, one or two operations,
        or None, meaning this pair cannot be optimized.
        N)r#   gettype)r$   r5   r7   
in_betweenmethodr%   r%   r&   r0      s    $zMigrationOptimizer.reducec             C   s<   t  | t j  r" | j d d  S| j j | j j f Sd S)zu
        Takes either a model class or a "appname.ModelName" string
        and returns (appname, modelname)
        .r(   N)
isinstancer   string_typessplitZ_metar+   object_name)r$   modelr%   r%   r&   model_to_key   s    	zMigrationOptimizer.model_to_keyc             C   s0   | j  | j  k r, | j j d d  r, g  Sd S)zE
        Folds a CreateModel and a DeleteModel into nothing.
        proxyFN)
name_loweroptionsr8   )r$   r5   r7   r:   r%   r%   r&   r      s    z3MigrationOptimizer.reduce_create_model_delete_modelc          
   C   sJ   | j  | j k rF t | j d | j d | j d | j d | j g Sd S)z6
        Folds a model rename into its create
        fieldsrE   basesmanagersN)rD   old_name_lowerr	   new_namerF   rE   rG   rH   )r$   r5   r7   r:   r%   r%   r&   r      s    				z3MigrationOptimizer.reduce_create_model_rename_modelc             C   s,   | j  | j k r( t | j | j  g Sd S)z7
        Folds a model rename into another one
        N)new_name_lowerrI   r   old_namerJ   )r$   r5   r7   r:   r%   r%   r&   r      s    z3MigrationOptimizer.reduce_rename_model_rename_modelc             C   s   | j  | j  k r | g Sd S)z}
        Folds two AlterModelTable, AlterFooTogether, or AlterOrderWithRespectTo
        operations into the latter.
        N)rD   )r$   r5   r7   r:   r%   r%   r&   r      s    z1MigrationOptimizer.reduce_alter_model_alter_modelc             C   s   | j  | j  k r | g Sd S)zR
        Folds an AlterModelSomething and a DeleteModel into just delete.
        N)rD   )r$   r5   r7   r:   r%   r%   r&   r      s    z2MigrationOptimizer.reduce_alter_model_delete_modelc          
   C   s  | j  | j k rt | j d  r | j j r x | D] } |  j | j j j  \ } } | j | |  rq d  St | j j d d   r7 |  j | j j j	  \ } } | j | |  r d  Sq7 q7 Wn  t
 | j d | j | j | j f g d | j d | j d | j g Sd  S)Nremote_fieldthroughrF   rE   rG   rH   )rD   model_name_lowerhasattrfieldrM   rB   rA   references_modelgetattrrN   r	   namerF   rE   rG   rH   )r$   r5   r7   r:   Zbetweenr+   r@   r%   r%   r&   r      s     			z0MigrationOptimizer.reduce_create_model_add_fieldc          
      s]   | j    j k rY t | j d   f d d   | j D d | j d | j d | j g Sd  S)NrF   c                s:   g  |  ]0 \ } } | |   j  k r-   j n | f  q Sr%   )rT   rQ   ).0nv)r7   r%   r&   
<listcomp>   s   	zFMigrationOptimizer.reduce_create_model_alter_field.<locals>.<listcomp>rE   rG   rH   )rD   rO   r	   rT   rF   rE   rG   rH   )r$   r5   r7   r:   r%   )r7   r&   r      s    			z2MigrationOptimizer.reduce_create_model_alter_fieldc          
      s]   | j    j k rY t | j d   f d d   | j D d | j d | j d | j g Sd  S)NrF   c                s7   g  |  ]- \ } } | j      j k r | | f  q Sr%   )lowerrD   )rU   rV   rW   )r7   r%   r&   rX      s   		zGMigrationOptimizer.reduce_create_model_remove_field.<locals>.<listcomp>rE   rG   rH   )rD   rO   r	   rT   rF   rE   rG   rH   )r$   r5   r7   r:   r%   )r7   r&   r      s    			z3MigrationOptimizer.reduce_create_model_remove_fieldc          
      s]   | j    j k rY t | j d   f d d   | j D d | j d | j d | j g Sd  S)NrF   c                s:   g  |  ]0 \ } } |   j  k r*   j n | | f  q Sr%   )rL   rJ   )rU   rV   rW   )r7   r%   r&   rX     s   	zGMigrationOptimizer.reduce_create_model_rename_field.<locals>.<listcomp>rE   rG   rH   )rD   rO   r	   rT   rF   rE   rG   rH   )r$   r5   r7   r:   r%   )r7   r&   r   	  s    			z3MigrationOptimizer.reduce_create_model_rename_fieldc             C   s9   | j  | j k r5 | j | j | j  r5 | | g Sd  S)N)rD   rO   references_field
model_namerT   )r$   r5   r7   r:   r%   r%   r&   r     s    z:MigrationOptimizer.reduce_alter_model_addalterremove_fieldc             C   s9   | j  | j k r5 | j | j | j  r5 | | g Sd  S)N)rD   rO   rZ   r[   rL   )r$   r5   r7   r:   r%   r%   r&   r     s    z2MigrationOptimizer.reduce_alter_model_rename_fieldc             C   sM   | j  | j  k rI | j | j k rI t d | j d | j d | j  g Sd  S)Nr[   rT   rQ   )rO   rD   r   r[   rT   rQ   )r$   r5   r7   r:   r%   r%   r&   r   $  s    		z/MigrationOptimizer.reduce_add_field_alter_fieldc             C   s,   | j  | j  k r( | j | j k r( g  Sd  S)N)rO   rD   )r$   r5   r7   r:   r%   r%   r&   r   /  s    z0MigrationOptimizer.reduce_add_field_remove_fieldc             C   sM   | j  | j  k rI | j | j k rI t d | j d | j d | j  g Sd  S)Nr[   rT   rQ   )rO   rD   rI   r   r[   rJ   rQ   )r$   r5   r7   r:   r%   r%   r&   r   4  s    		z0MigrationOptimizer.reduce_add_field_rename_fieldc             C   s/   | j  | j  k r+ | j | j k r+ | g Sd  S)N)rO   rD   )r$   r5   r7   r:   r%   r%   r&   r    ?  s    z2MigrationOptimizer.reduce_alter_field_remove_fieldc             C   sP   | j  | j  k rL | j | j k rL | t d | j d | j d | j  g Sd  S)Nr[   rT   rQ   )rO   rD   rI   r   r[   rJ   rQ   )r$   r5   r7   r:   r%   r%   r&   r!   D  s    		z2MigrationOptimizer.reduce_alter_field_rename_fieldc             C   sD   | j  | j  k r@ | j | j k r@ t | j | j | j  g Sd  S)N)rO   rK   rI   r   r[   rL   rJ   )r$   r5   r7   r:   r%   r%   r&   r"   P  s    z3MigrationOptimizer.reduce_rename_field_rename_fieldc             C   sf   t  | |  j  r. | j | j |  s. d Sn  t  | |  j  rb | j | j | j |  sb d Sn  d S)z
        Returns True if it's possible to optimize 'operation' with something
        the other side of 'other'. This is possible if, for example, they
        affect different models.
        TF)r=   r   rR   rT   r   rZ   r[   )r$   r5   r7   r+   r%   r%   r&   r2   ]  s    z'MigrationOptimizer.can_optimize_through)__name__
__module____qualname____doc__r'   r-   r)   r0   rB   r   r   r   r   r   r   r   r   r   r   r   r   r   r   r    r!   r"   r2   r%   r%   r%   r&   r      s0   	9
	r   N)
__future__r   Zdjango.db.migrationsr   r   r   r   r   r   r	   r
   r   r   r   Zdjango.utilsr   objectr   r%   r%   r%   r&   <module>   s   L