37 lines
886 B
Haskell
37 lines
886 B
Haskell
module ACPI (ACPIEvent(..), acpiMagic, isDischarging) where
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import Control.Exception
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import Text.Read
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data ACPIEvent = Power | Sleep | LidClose deriving (Eq)
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instance Show ACPIEvent where
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show Power = "power"
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show Sleep = "sleep"
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-- show LidOpen = "olid"
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show LidClose = "clid"
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instance Read ACPIEvent where
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readPrec = do
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Ident s <- lexP
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case s of
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-- TODO this isn't DRY
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"power" -> return Power
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"sleep" -> return Sleep
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"clid" -> return LidClose
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_ -> pfail
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-- TODO use a data type that enforces strings of max length 5
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acpiMagic :: String
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acpiMagic = "%acpi"
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isDischarging :: IO (Maybe Bool)
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isDischarging = do
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status <- try $ readFile "/sys/class/power_supply/BAT0/status"
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:: IO (Either IOException String)
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case status of
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Left e -> do
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print e
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return Nothing
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Right s -> return $ Just (s == "Discharging")
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