上我偶然发现了一个奇怪的内存前一个问题(haskell-data-hashset-from-unordered-container-performance-for-large-sets)上的一些意见工作泄漏管道:生产内存泄漏
module Main where
import System.Environment (getArgs)
import Control.Monad.Trans.Resource (runResourceT)
import Data.Attoparsec.ByteString (sepBy, Parser)
import Data.Attoparsec.ByteString.Char8 (decimal, char)
import Data.Conduit
import qualified Data.Conduit.Attoparsec as CA
import qualified Data.Conduit.Binary as CB
import qualified Data.Conduit.List as CL
main :: IO()
main = do (args:_) <- getArgs
writeFile "input.txt" $ unlines $ map show [1..4 :: Int]
case args of "list" -> m1
"fail" -> m2
"listlist" -> m3
"memoryleak" -> m4
--UPDATE
"bs-lines":_ -> m5
"bs":_ -> m6
_ -> putStr $ unlines ["Usage: conduit list"
," fail"
," listlist"
," memoryleak"
--UPDATE
," bs-lines"
," bs"
]
m1,m2,m3,m4 :: IO()
m1 = do hs <- runResourceT
$ CB.sourceFile "input.txt"
$$ CB.lines
=$= CA.conduitParser (decimal :: Parser Int)
=$= CL.map snd
=$= CL.consume
print hs
m2 = do hs <- runResourceT
$ CB.sourceFile "input.txt"
$$ CA.conduitParser (decimal :: Parser Int)
=$= CL.map snd
=$= CL.consume
print hs
m3 = do hs <- runResourceT
$ CB.sourceFile "input.txt"
$$ CB.lines
=$= CA.conduitParser (decimal `sepBy` (char '\n') :: Parser [Int])
=$= CL.map snd
=$= CL.consume
print hs
m4 = do hs <- runResourceT
$ CB.sourceFile "input.txt"
$$ CA.conduitParser (decimal `sepBy` (char '\n') :: Parser [Int])
=$= CL.map snd
=$= CL.consume
print hs
-- UPDATE
m5 = do inpt <- BS.lines <$> BS.readFile "input.txt"
let Right hs = mapM (parseOnly (decimal :: Parser Int)) inpt
print hs
m6 = do inpt <- BS.readFile "input.txt"
let Right hs = (parseOnly (decimal `sepBy` (char '\n') :: Parser [Int])) inpt
print hs
下面是一些例子输出:
$ > stack exec -- example list
[1234]
$ > stack exec -- example listlist
[[1234]]
$ > stack exec -- conduit fail
conduit: ParseError {errorContexts = [], errorMessage = "Failed reading: takeWhile1", errorPosition = 1:2}
$ > stack exec -- example memoryleak
(Ctrl+C)
-- UPDATE
$ > stack exec -- example bs-lines
[1,2,3,4]
$ > stack exec -- example bs
[1,2,3,4]
现在的问题我有:
- 为什么
m1
不生产[1,2,3,4]
? - 为什么
m2
失败? - 为什么
m4
与所有其他版本相比表现完全不同,并产生空间泄漏?
你用懒惰的I/O和attoparsec本身检查你的代码吗?如果attoparsec的回溯数据超过预期,我不会感到惊讶。 –
@MichaelSnoyman我用bytestring/attoparsec版本更新了我的问题,但我不确定它是否等同于导管版本(因为我对导管不太熟悉)。至少它产生了我期望的产出。 – epsilonhalbe