Sha256: 1897db0d1d1a390cb2fb3dafcac0398d0a47082245f110b24a3161844fdf098c
Contents?: true
Size: 1.99 KB
Versions: 9
Compression:
Stored size: 1.99 KB
Contents
# frozen_string_literal: true
module MiniSql
module Postgres
class DeserializerCache
DEFAULT_MAX_SIZE = 500
def initialize(max_size = nil)
@cache = {}
@max_size = max_size || DEFAULT_MAX_SIZE
end
def materializer(result)
key = result.fields.join(',')
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
materializer
end
def materialize(result, decorator_module = nil)
return [] if result.ntuples == 0
key = result.fields.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
i = 0
r = []
# quicker loop
while i < result.ntuples
r << materializer.materialize(result, i)
i += 1
end
r
end
private
def new_row_materializer(result)
fields = result.fields
i = 0
while i < fields.length
# special handling for unamed column
if fields[i] == "?column?"
fields[i] = "column#{i}"
end
i += 1
end
Class.new do
extend MiniSql::Decoratable
include MiniSql::Result
attr_accessor(*fields)
instance_eval <<~RUBY
def materialize(pg_result, index)
r = self.new
#{col = -1; fields.map { |f| "r.#{f} = pg_result.getvalue(index, #{col += 1})" }.join("; ")}
r
end
RUBY
end
end
end
end
end
Version data entries
9 entries across 9 versions & 1 rubygems