class MiniSql::Sqlite::DeserializerCache

Constants

DEFAULT_MAX_SIZE

Public Class Methods

new(max_size = nil) click to toggle source
# File lib/mini_sql/sqlite/deserializer_cache.rb, line 9
def initialize(max_size = nil)
  @cache = {}
  @max_size = max_size || DEFAULT_MAX_SIZE
end

Public Instance Methods

materialize(result, decorator_module = nil) click to toggle source
# File lib/mini_sql/sqlite/deserializer_cache.rb, line 14
def materialize(result, decorator_module = nil)

  key = result.columns.join(',')

  # trivial fast LRU implementation
  materializer = @cache.delete(key)
  if materializer
    @cache[key] = materializer
  else
    materializer = @cache[key] = new_row_materializer(result)
    @cache.shift if @cache.length > @max_size
  end

  if decorator_module
    materializer = materializer.decorated(decorator_module)
  end

  r = []
  # quicker loop
  while !result.eof?
    data = result.next
    if data
      r << materializer.materialize(data)
    end
  end
  r
end

Private Instance Methods

new_row_materializer(result) click to toggle source
# File lib/mini_sql/sqlite/deserializer_cache.rb, line 44
      def new_row_materializer(result)
        fields = result.columns

        Class.new do
          extend MiniSql::Decoratable
          include MiniSql::Result

          attr_accessor(*fields)

          instance_eval <<~RUBY
            def materialize(data)
              r = self.new
              #{col = -1; fields.map { |f| "r.#{f} = data[#{col += 1}]" }.join("; ")}
              r
            end
          RUBY
        end
      end