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# File 'lib/multirow_counter/extension.rb', line 3
def multirow_counter(counter_name, options)
num_rows = options[:rows] || raise(ArgumentError, "You need to specify how many rows will be used eg. :rows => 3")
class_name = self.name
assoc = class_name.foreign_key
table_name = [class_name, counter_name.to_s.camelize].join.tableize
getter = lambda do
ivar_name = "@#{counter_name}"
if x = instance_variable_get(ivar_name)
return x
else
val = ActiveRecord::Base.connection.select_value " SELECT IFNULL(SUM(value),0) FROM \#{table_name} WHERE \#{assoc}=\#{self.id}\n SQL\n instance_variable_set(ivar_name, val.to_i)\n end\n end\n\n define_method(counter_name, &getter)\n define_method(\"multirow_counter_\#{counter_name}\", &getter)\n\n # define increment method\n define_method(\"new_\#{counter_name}!\") do |incr = 1|\n ivar_name = \"@\#{counter_name}\"\n if x = instance_variable_get(ivar_name)\n instance_variable_set(ivar_name, x + incr)\n end\n\n randomly_selected_counter_row = rand(num_rows) + 1\n\n num_changed = ActiveRecord::Base.connection.update <<-SQL\n UPDATE \#{table_name} SET value=value+\#{Integer(incr)}\n WHERE \#{assoc}=\#{self.id} AND counter_id=\#{randomly_selected_counter_row}\n SQL\n\n if num_changed == 0 # row doesn't exist. We create it instead.\n ActiveRecord::Base.connection.execute <<-SQL\n INSERT INTO \#{table_name} (\#{assoc}, counter_id, value)\n VALUES (\#{self.id}, \#{randomly_selected_counter_row}, \#{Integer(incr)})\n ON DUPLICATE KEY UPDATE value=value+\#{Integer(incr)};\n SQL\n end\n end\n\n define_method(\"reload_with_\#{counter_name}_reset\") do\n instance_variable_set(\"@\#{counter_name}\", nil)\n send(\"reload_without_\#{counter_name}_reset\")\n end\n\n alias_method_chain :reload, \"\#{counter_name}_reset\".to_sym\nend\n"
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