141 lines
4.8 KiB
Haskell
141 lines
4.8 KiB
Haskell
{-# LANGUAGE ViewPatterns #-}
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--------------------------------------------------------------------------------
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-- | Random IO-ish functions used throughtout xmonad
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--
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-- Most (probably all) of these functions are intended to work with sysfs where
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-- some safe assumptions can be made about file contents.
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module XMonad.Internal.IO
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( readInt
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, readBool
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, readPercent
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, writeInt
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, writeBool
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, writePercent
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, writePercentMin
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, writePercentMax
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, decPercent
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, incPercent
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-- , isReadable
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-- , isWritable
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, PermResult(..)
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, getPermissionsSafe
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, waitUntilExit
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) where
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import Data.Char
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import Data.Text (pack, unpack)
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import Data.Text.IO as T (readFile, writeFile)
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import RIO
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import RIO.Directory
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import RIO.FilePath
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import System.IO.Error
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--------------------------------------------------------------------------------
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-- | read
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readInt :: (Read a, Integral a) => FilePath -> IO a
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readInt = fmap (read . takeWhile isDigit . unpack) . T.readFile
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readBool :: FilePath -> IO Bool
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readBool = fmap (==(1 :: Int)) . readInt
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--------------------------------------------------------------------------------
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-- | write
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writeInt :: (Show a, Integral a) => FilePath -> a -> IO ()
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writeInt f = T.writeFile f . pack . show
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writeBool :: FilePath -> Bool -> IO ()
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writeBool f b = writeInt f ((if b then 1 else 0) :: Int)
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--------------------------------------------------------------------------------
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-- | percent-based read/write
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--
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-- "Raw" values are whatever is stored in sysfs and "percent" is the user-facing
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-- value. Assume that the file being read has a min of 0 and an unchanging max
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-- given by a runtime argument, which is scaled linearly to the range 0-100
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-- (percent).
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rawToPercent :: (Integral a, Integral b, Read b, RealFrac c) => (a, a) -> b -> c
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rawToPercent (lower, upper) raw =
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100 * (fromIntegral raw - fromIntegral lower) / fromIntegral (upper - lower)
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-- rawToPercent upper raw = 100 * fromIntegral raw / fromIntegral upper
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readPercent :: (Integral a, RealFrac b) => (a, a) -> FilePath -> IO b
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readPercent bounds path = do
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i <- readInt path
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return $ rawToPercent bounds (i :: Integer)
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percentToRaw :: (Integral a, RealFrac b, Integral c) => (a, a) -> b -> c
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percentToRaw (lower, upper) perc = round $
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fromIntegral lower + perc / 100.0 * (fromIntegral upper - fromIntegral lower)
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writePercent :: (Integral a, RealFrac b) => (a, a) -> FilePath -> b -> IO b
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writePercent bounds path perc = do
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let t | perc > 100 = 100
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| perc < 0 = 0
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| otherwise = perc
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writeInt path (percentToRaw bounds t :: Int)
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return t
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writePercentMin :: (Integral a, RealFrac b) => (a, a) -> FilePath -> IO b
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writePercentMin bounds path = writePercent bounds path 0
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writePercentMax :: (Integral a, RealFrac b) => (a, a) -> FilePath -> IO b
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writePercentMax bounds path = writePercent bounds path 100
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shiftPercent :: (Integral a, RealFrac b) => (b -> b -> b) -> Int -> FilePath
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-> (a, a) -> IO b
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shiftPercent f steps path bounds = writePercent bounds path . f stepsize
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=<< readPercent bounds path
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where
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stepsize = 100 / fromIntegral steps
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incPercent :: (Integral a, RealFrac b) => Int -> FilePath -> (a, a) -> IO b
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incPercent = shiftPercent (+)
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decPercent :: (Integral a, RealFrac b) => Int -> FilePath -> (a, a) -> IO b
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decPercent = shiftPercent subtract -- silly (-) operator thingy error
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--------------------------------------------------------------------------------
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-- | permission query
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data PermResult a = PermResult a | NotFoundError | PermError
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deriving (Show, Eq)
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-- instance Functor PermResult where
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-- fmap f (PermResult r) = PermResult $ f r
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-- fmap _ NotFoundError = NotFoundError
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-- fmap _ PermError = PermError
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getPermissionsSafe :: FilePath -> IO (PermResult Permissions)
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getPermissionsSafe f = do
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r <- tryIOError $ getPermissions f
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return $ case r of
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Right z -> PermResult z
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Left (isPermissionError -> True) -> PermError
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Left (isDoesNotExistError -> True) -> NotFoundError
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-- the above error should be the only ones thrown by getPermission,
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-- so the catchall case should never happen
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_ -> error "Unknown permission error"
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-- isReadable :: FilePath -> IO (PermResult Bool)
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-- isReadable = fmap (fmap readable) . getPermissionsSafe
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-- isWritable :: FilePath -> IO (PermResult Bool)
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-- isWritable = fmap (fmap writable) . getPermissionsSafe
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-- | Block until a PID has exited.
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-- Use this to control flow based on a process that was not explicitly started
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-- by the Haskell runtime itself, and thus has no data structures to query.
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waitUntilExit :: (Show t, Num t) => t -> IO ()
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waitUntilExit pid = do
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res <- doesDirectoryExist $ "/proc" </> show pid
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when res $ do
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threadDelay 100000
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waitUntilExit pid
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