class ActiveRecord::ConnectionAdapters::PoolConfig

def connection_descriptor=(connection_descriptor)
  case connection_descriptor
  when ConnectionHandler::ConnectionDescriptor
    @connection_descriptor = connection_descriptor
  else
    @connection_descriptor = ConnectionHandler::ConnectionDescriptor.new(connection_descriptor.name, connection_descriptor.primary_class?)
  end
end

def discard_pool!
  return unless @pool
  synchronize do
    return unless @pool
    @pool.discard!
    @pool = nil
  end
end

def discard_pools!
  INSTANCES.each_key(&:discard_pool!)
end

def disconnect!(automatic_reconnect: false)
  return unless @pool
  synchronize do
    return unless @pool
    @pool.automatic_reconnect = automatic_reconnect
    @pool.disconnect!
  end
  nil
end

def disconnect_all!
  INSTANCES.each_key { |c| c.disconnect!(automatic_reconnect: true) }
end

def initialize(connection_class, db_config, role, shard)
  super()
  @server_version = nil
  self.connection_descriptor = connection_class
  @db_config = db_config
  @role = role
  @shard = shard
  @pool = nil
  INSTANCES[self] = self
end

def pool
  @pool || synchronize { @pool ||= ConnectionAdapters::ConnectionPool.new(self) }
end

def schema_reflection
  @schema_reflection ||= SchemaReflection.new(db_config.lazy_schema_cache_path)
end

def server_version(connection)
  @server_version || synchronize { @server_version ||= connection.get_database_version }
end