Module: Detailed::AssociationScope

Included in:
ActiveRecord::Associations::AssociationScope
Defined in:
lib/detailed.rb

Class Method Summary collapse

Class Method Details

.included(cl) ⇒ Object 



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# File 'lib/detailed.rb', line 107

def self.included cl
  cl.class_eval do
    def maybe_split(table, field, reflection)
      if field.match /\./
        table, field = field.split(/\./, 2)
        table = alias_tracker.aliased_table_for(table, table_alias_for(reflection, self.reflection != reflection))
      end
                
      [table, field]
    end
    
    # Extend add_constraints support for "table.column" notation
    #
    # This gives us power to do eg.:
    #  has_many :frames, foreign_key: "project_frame_details.glass_id"        
    def add_constraints(scope)
      tables = construct_tables
      
      chain.each_with_index do |reflection, i|
        table, foreign_table = tables.shift, tables.first
        
        if reflection.source_macro == :has_and_belongs_to_many
          join_table = tables.shift
                       
          scope = scope.joins(join(
                                   join_table,
                                   table[association_primary_key].
                                  eq(join_table[association_foreign_key])
                                  ))
          
          table, foreign_table = join_table, tables.first
        end
      
        if reflection.source_macro == :belongs_to
          if reflection.options[:polymorphic]
            key = reflection.association_primary_key(self.klass)
          else
            key = reflection.association_primary_key
          end
          
          foreign_key = reflection.foreign_key
        else
          key         = reflection.foreign_key
          foreign_key = reflection.active_record_primary_key
        end
        
        # this is our addition
        table, key = maybe_split(table, key, reflection)
        foreign_table, foreign_key = maybe_split(foreign_table, foreign_key, reflection)
        # end
        
        if reflection == chain.last              
          bind_val = bind scope, table.table_name, key.to_s, owner[foreign_key]
          scope    = scope.where(table[key].eq(bind_val))
          
          if reflection.type
            value    = owner.class.base_class.name
            bind_val = bind scope, table.table_name, reflection.type.to_s, value
            scope    = scope.where(table[reflection.type].eq(bind_val))
          end
        else
          constraint = table[key].eq(foreign_table[foreign_key])
          
          if reflection.type
            type = chain[i + 1].klass.base_class.name
            constraint = constraint.and(table[reflection.type].eq(type))
          end
          
          scope = scope.joins(join(foreign_table, constraint))
        end
        
        # Exclude the scope of the association itself, because that
        # was already merged in the #scope method.
        scope_chain[i].each do |scope_chain_item|
          klass = i == 0 ? self.klass : reflection.klass
          item  = eval_scope(klass, scope_chain_item)
          
          if scope_chain_item == self.reflection.scope
            scope.merge! item.except(:where, :includes)
          end
          
          scope.includes! item.includes_values
          scope.where_values += item.where_values
          scope.order_values |= item.order_values
        end
      end
      
      scope
    end
  end
end