refactor of migrations

Author: dvdmgl

pg_fts/migrations.py

@@ -123,10 +123,9 @@ def delete_index(self, model, vector_field):
         )
 
 
-class UpdateVectorOperation(Operation):
+class BaseVectorOperation(Operation):
     """
-    Updates changes to :class:`~pg_fts.fields.TSVectorField` for existing
-    models
+    Base migrations class
 
     :param name: The Model name
 
@@ -136,6 +135,8 @@ class UpdateVectorOperation(Operation):
     reduces_to_sql = True
     reversible = True
     sql_creator = PgFtsSQL()
+    forward_fn = None
+    backward_fn = None
 
     def __init__(self, name, fts_vector):
         self.name = name
@@ -149,61 +150,76 @@ def database_forwards(self, app_label, schema_editor, from_state,
 
         model = from_state.render().get_model(app_label, self.name)
         vector_field = model._meta.get_field_by_name(self.fts_vector)[0]
-        schema_editor.execute(self.sql_creator.update_vector(
+        schema_editor.execute(self.forward_fn(
             model,
             vector_field
         ))
 
     def database_backwards(self, app_label, schema_editor, from_state,
                            to_state):
-        pass
+
+        model = from_state.render().get_model(app_label, self.name)
+        vector_field = model._meta.get_field_by_name(self.fts_vector)[0]
+
+        schema_editor.execute(self.backward_fn(
+            model,
+            vector_field
+        ))
 
     def describe(self):
         return "Create trigger `%s` for model `%s`" % (
             self.fts_vector, self.name
         )
 
 
-class CreateFTSTriggerOperation(Operation):
+class UpdateVectorOperation(BaseVectorOperation):
     """
-    Creates a :pg_docs:`custom trigger <textsearch-features.html#TEXTSEARCH-UPDATE-TRIGGERS>`
-    for updating the :class:`~pg_fts.fields.TSVectorField` with rank values
+    Updates changes to :class:`~pg_fts.fields.TSVectorField` for existing
+    models
 
     :param name: The Model name
 
     :param fts_vector: The :class:`~pg_fts.fields.TSVectorField` field name
     """
 
-    reduces_to_sql = True
-    reversible = True
-
-    sql_creator = PgFtsSQL()
-
     def __init__(self, name, fts_vector):
         self.name = name
         self.fts_vector = fts_vector
+        self.forward_fn = self.sql_creator.update_vector
 
-    def state_forwards(self, app_label, state):
+    def database_backwards(self, app_label, schema_editor, from_state,
+                           to_state):
         pass
 
-    def database_forwards(self, app_label, schema_editor, from_state,
-                          to_state):
+    def describe(self):
+        return "Create trigger `%s` for model `%s`" % (
+            self.fts_vector, self.name
+        )
 
-        model = from_state.render().get_model(app_label, self.name)
-        vector_field = model._meta.get_field_by_name(self.fts_vector)[0]
 
-        schema_editor.execute(self.sql_creator.create_fts_trigger(
-            model,
-            vector_field
-        ))
+class CreateFTSTriggerOperation(BaseVectorOperation):
+    """
+    Creates a :pg_docs:`custom trigger <textsearch-features.html#TEXTSEARCH-UPDATE-TRIGGERS>`
+    for updating the :class:`~pg_fts.fields.TSVectorField` with rank values
+
+    :param name: The Model name
+
+    :param fts_vector: The :class:`~pg_fts.fields.TSVectorField` field name
+    """
+
+    def __init__(self, name, fts_vector):
+        self.name = name
+        self.fts_vector = fts_vector
+        self.forward_fn = self.sql_creator.create_fts_trigger
+        self.backward_fn = self.sql_creator.delete_trigger
 
     def database_backwards(self, app_label, schema_editor, from_state,
                            to_state):
 
         model = from_state.render().get_model(app_label, self.name)
         vector_field = model._meta.get_field_by_name(self.fts_vector)[0]
 
-        schema_editor.execute(self.sql_creator.delete_trigger(
+        schema_editor.execute(self.backward_fn(
             model,
             vector_field
         ))
@@ -214,7 +230,7 @@ def describe(self):
         )
 
 
-class DeleteFTSTriggerOperation(Operation):
+class DeleteFTSTriggerOperation(BaseVectorOperation):
     """
     Deletes trigger generated by :class:`~pg_fts.migrations.CreateFTSTriggerOperation`
 
@@ -223,47 +239,19 @@ class DeleteFTSTriggerOperation(Operation):
     :param fts_vector: The :class:`~pg_fts.fields.TSVectorField` field name
     """
 
-    reduces_to_sql = True
-    reversible = True
-
-    sql_creator = PgFtsSQL()
-
     def __init__(self, name, fts_vector):
         self.name = name
         self.fts_vector = fts_vector
-
-    def state_forwards(self, app_label, state):
-        pass
-
-    def database_forwards(self, app_label, schema_editor, from_state,
-                          to_state):
-
-        model = from_state.render().get_model(app_label, self.name)
-        vector_field = model._meta.get_field_by_name(self.fts_vector)[0]
-
-        schema_editor.execute(self.sql_creator.delete_trigger(
-            model,
-            vector_field
-        ))
-
-    def database_backwards(self, app_label, schema_editor, from_state,
-                           to_state):
-
-        model = from_state.render().get_model(app_label, self.name)
-        vector_field = model._meta.get_field_by_name(self.fts_vector)[0]
-
-        schema_editor.execute(self.sql_creator.create_fts_trigger(
-            model,
-            vector_field
-        ))
+        self.forward_fn = self.sql_creator.delete_trigger
+        self.backward_fn = self.sql_creator.create_fts_trigger
 
     def describe(self):
         return "Delete trigger `%s` for model `%s`" % (
             self.fts_vector, self.name
         )
 
 
-class CreateFTSIndexOperation(Operation):
+class CreateFTSIndexOperation(BaseVectorOperation):
     """
     Creates a index for :class:`~pg_fts.fields.TSVectorField`
 
@@ -276,10 +264,6 @@ class CreateFTSIndexOperation(Operation):
 
     # http://www.postgresql.org/docs/9.3/static/textsearch-indexes.html
     INDEXS = ('gin', 'gist')
-    reduces_to_sql = True
-
-    reversible = True
-    sql_creator = PgFtsSQL()
 
     def __init__(self, name, fts_vector, index):
         assert index in self.INDEXS, "Invalid index '%s'. Options %s " % (
@@ -319,28 +303,14 @@ def describe(self):
         )
 
 
-class DeleteFTSIndexOperation(Operation):
+class DeleteFTSIndexOperation(CreateFTSIndexOperation):
     """
     Removes index created by :class:`~pg_fts.migrations.CreateFTSIndexOperation`
 
     :param name: The Model name
     :param fts_vector: The :class:`~pg_fts.fields.TSVectorField` field name
     :param index: The type of index 'gin' or 'gist' for more information go to
     """
-    reduces_to_sql = True
-    reversible = True
-    INDEXS = ('gin', 'gist')
-    sql_creator = PgFtsSQL()
-
-    def __init__(self, name, fts_vector, index):
-        assert index in self.INDEXS, "Invalid index '%s'. Options %s " % (
-            index, ', '.join(self.INDEXS))
-        self.name = name
-        self.fts_vector = fts_vector
-        self.index = index
-
-    def state_forwards(self, app_label, state):
-        pass
 
     def database_forwards(self, app_label, schema_editor, from_state,
                           to_state):