enum_column_adapter.rb

# This module provides all the column helper methods to deal with the
# values and adds the common type management code for the adapters.


# try rails 3.1, then rails 3.2+, mysql column adapters
column_class = if defined? ActiveRecord::ConnectionAdapters::Mysql2Column
  ActiveRecord::ConnectionAdapters::Mysql2Column
elsif defined? ActiveRecord::ConnectionAdapters::MysqlColumn
  ActiveRecord::ConnectionAdapters::MysqlColumn
elsif defined? ActiveRecord::ConnectionAdapters::Mysql2Adapter::Column
  ActiveRecord::ConnectionAdapters::Mysql2Adapter::Column
elsif defined? ActiveRecord::ConnectionAdapters::MysqlAdapter::Column
  ActiveRecord::ConnectionAdapters::MysqlAdapter::Column
elsif defined? ActiveRecord::ConnectionAdapters::MySQL::Column
  ActiveRecord::ConnectionAdapters::MySQL::Column
end

if column_class
  column_class.class_eval do

    if instance_methods.include?(:extract_default)
      alias __extract_default_enum extract_default
      def extract_default
        if type == :enum
          if @default == '' || @default.nil?
            @default = nil
          else
            @default = @default.intern
          end
        end
        __extract_default_enum
      end
    end

    def __enum_type_cast(value)
      if type == :enum
        self.class.value_to_symbol(value)
      else
        __type_cast_enum(value)
      end
    end

    if instance_methods.include?(:type_cast_from_database)
      alias __type_cast_enum type_cast_from_database
      # Convert to a symbol.
      def type_cast_from_database(value)
        __enum_type_cast(value)
      end
    elsif instance_methods.include?(:type_cast)
      alias __type_cast_enum type_cast
      def type_cast(value)
        __enum_type_cast(value)
      end
    end

    # Deprecated in Rails 4.1
    if instance_methods.include?(:type_cast_code)
      alias __type_cast_code_enum type_cast_code
      # Code to convert to a symbol.
      def type_cast_code(var_name)
        if type == :enum
          "#{self.class.name}.value_to_symbol(#{var_name})"
        else
          __type_cast_code_enum(var_name)
        end
      end
    end

    class << self
      # Safely convert the value to a symbol.
      def value_to_symbol(value)
        case value
        when Symbol
          value
        when String
          value.empty? ? nil : value.intern
        else
          nil
        end
      end
    end

  private

    # Deprecated in Rails 4.2
    if private_instance_methods.include?(:simplified_type)
      alias __simplified_type_enum simplified_type
      # The enum simple type.
      def simplified_type(field_type)
        if field_type =~ /enum/i
          :enum
        else
          __simplified_type_enum(field_type)
        end
      end
    end

    # Deprecated in Rails 4.2
    if private_instance_methods.include?(:extract_limit)
      alias __extract_limit_enum extract_limit
      def extract_limit(sql_type)
        if sql_type =~ /^enum/i
          sql_type.sub(/^enum\('(.+)'\)/i, '\1').split("','").map { |v| v.intern }
        else
          __extract_limit_enum(sql_type)
        end
      end
    end

  end
end