-----------------------------------------------------------------------------
-- |
-- Module : Plugins.Monitors.Batt.Linux
-- Copyright : (c) 2010-2013, 2015, 2016, 2018, 2019, 2022 Jose A Ortega
-- (c) 2010 Andrea Rossato, Petr Rockai
-- License : BSD-style (see LICENSE)
--
-- Maintainer : Jose A. Ortega Ruiz <jao@gnu.org>
-- Stability : unstable
-- Portability : unportable
--
-- A battery monitor for Xmobar
--
-----------------------------------------------------------------------------
module Xmobar.Plugins.Monitors.Batt.Linux (readBatteries) where
import Xmobar.Plugins.Monitors.Batt.Common ( BattOpts(..)
, Result(..)
, Status(..)
, maybeAlert)
import Control.Monad (unless)
import Control.Exception (SomeException, handle)
import System.FilePath ((</>))
import System.IO (IOMode(ReadMode), hGetLine, withFile, Handle)
import Data.List (sort, sortBy, group)
import Data.Maybe (fromMaybe)
import Data.Ord (comparing)
import Text.Read (readMaybe)
data Files = Files
{ fEFull :: String
, fCFull :: String
, fEFullDesign :: String
, fCFullDesign :: String
, fENow :: String
, fCNow :: String
, fVoltage :: String
, fVoltageMin :: String
, fCurrent :: String
, fPower :: String
, fStatus :: String
, fBat :: String
} deriving Eq
-- the default basenames of the possibly available attributes exposed
-- by the kernel
defaultFiles :: Files
defaultFiles = Files
{ fEFull = "energy_full"
, fCFull = "charge_full"
, fEFullDesign = "energy_full_design"
, fCFullDesign = "charge_full_design"
, fENow = "energy_now"
, fCNow = "charge_now"
, fVoltage = "voltage_now"
, fVoltageMin = "voltage_min_design"
, fCurrent = "current_now"
, fPower = "power_now"
, fStatus = "status"
, fBat = "BAT0"
}
type FilesAccessor = Files -> String
sysDir :: FilePath
sysDir = "/sys/class/power_supply"
battFile :: FilesAccessor -> Files -> FilePath
battFile accessor files = sysDir </> fBat files </> accessor files
grabNumber :: (Num a, Read a) => FilesAccessor -> Files -> IO (Maybe a)
grabNumber = grabFile (fmap read . hGetLine)
grabString :: FilesAccessor -> Files -> IO (Maybe String)
grabString = grabFile hGetLine
-- grab file contents returning Nothing if the file doesn't exist or
-- any other error occurs
grabFile :: (Handle -> IO a) -> FilesAccessor -> Files -> IO (Maybe a)
grabFile readMode accessor files =
handle (onFileError Nothing) (withFile f ReadMode (fmap Just . readMode))
where f = battFile accessor files
onFileError :: a -> SomeException -> IO a
onFileError returnOnError = const (return returnOnError)
-- get the filenames for a given battery name
batteryFiles :: String -> Files
batteryFiles bat = defaultFiles { fBat = bat }
data Battery = Battery
{ full :: !Float
, now :: !Float
, power :: !Float
, status :: !String
}
haveAc :: FilePath -> IO Bool
haveAc f =
handle (onFileError False) $
withFile (sysDir </> f) ReadMode (fmap (== "1") . hGetLine)
-- retrieve the currently drawn power in Watt
-- sc is a scaling factor which by kernel documentation must be 1e6
readBatPower :: Float -> Files -> IO (Maybe Float)
readBatPower sc f =
do pM <- grabNumber fPower f
cM <- grabNumber fCurrent f
vM <- grabNumber fVoltage f
return $ case (pM, cM, vM) of
(Just pVal, _, _) -> Just $ pVal / sc
(_, Just cVal, Just vVal) -> Just $ cVal * vVal / (sc * sc)
(_, _, _) -> Nothing
-- retrieve the maximum capacity in Watt hours
-- sc is a scaling factor which by kernel documentation must be 1e6
-- on getting the voltage: using voltage_min_design will probably underestimate
-- the actual energy content of the battery and using voltage_now will probably
-- overestimate it.
readBatCapacityFull :: Float -> Files -> IO (Maybe Float)
readBatCapacityFull sc f =
do cM <- grabNumber fCFull f
eM <- grabNumber fEFull f
cdM <- grabNumber fCFullDesign f
edM <- grabNumber fEFullDesign f
-- not sure if Voltage or VoltageMin is more accurate and if both
-- are always available
vM <- grabNumber fVoltageMin f
return $ case (eM, cM, edM, cdM, vM) of
(Just eVal, _, _, _, _) -> Just $ eVal / sc
(_, Just cVal, _, _, Just vVal) -> Just $ cVal * vVal / (sc * sc)
(_, _, Just eVal, _, _) -> Just $ eVal / sc
(_, _, _, Just cVal, Just vVal) -> Just $ cVal * vVal / (sc * sc)
(_, _, _, _, _) -> Nothing
-- retrieve the current capacity in Watt hours
-- sc is a scaling factor which by kernel documentation must be 1e6
-- on getting the voltage: using voltage_min_design will probably underestimate
-- the actual energy content of the battery and using voltage_now will probably
-- overestimate it.
readBatCapacityNow :: Float -> Files -> IO (Maybe Float)
readBatCapacityNow sc f =
do cM <- grabNumber fCNow f
eM <- grabNumber fENow f
vM <- grabNumber fVoltageMin f -- not sure if Voltage or
-- VoltageMin is more accurate
-- and if both are always
-- available
return $ case (eM, cM, vM) of
(Just eVal, _, _) -> Just $ eVal / sc
(_, Just cVal, Just vVal) -> Just $ cVal * vVal / (sc * sc)
(_, _, _) -> Nothing
readBatStatus :: Files -> IO (Maybe String)
readBatStatus = grabString fStatus
-- collect all relevant battery values with defaults of not available
readBattery :: Float -> Files -> IO Battery
readBattery sc files =
do cFull <- withDef 0 readBatCapacityFull
cNow <- withDef 0 readBatCapacityNow
pwr <- withDef 0 readBatPower
s <- withDef "Unknown" (const readBatStatus)
let cFull' = max cFull cNow -- sometimes the reported max
-- charge is lower than
return $ Battery (3600 * cFull') -- wattseconds
(3600 * cNow) -- wattseconds
(abs pwr) -- watts
s -- string: Discharging/Charging/Full
where withDef d reader = fromMaybe d `fmap` reader sc files
-- sortOn is only available starting at ghc 7.10
sortOn :: Ord b => (a -> b) -> [a] -> [a]
sortOn f =
map snd . sortBy (comparing fst) . map (\x -> let y = f x in y `seq` (y, x))
mostCommonDef :: Eq a => a -> [a] -> a
mostCommonDef x xs = head $ last $ [x] : sortOn length (group xs)
readBatteries :: BattOpts -> [String] -> IO Result
readBatteries opts bfs =
do let bfs'' = map batteryFiles bfs
bats <- mapM (readBattery (scale opts)) (take 3 bfs'')
ac <- haveAc (onlineFile opts)
let sign = if ac then 1 else -1
ft = sum (map full bats) -- total capacity when full
left = if ft > 0 then sum (map now bats) / ft else 0
watts = sign * sum (map power bats)
time = if watts == 0 then 0 else max 0 (sum $ map time' bats)
mwatts = if watts == 0 then 1 else sign * watts
time' b = (if ac then full b - now b else now b) / mwatts
statuses :: [Status]
statuses = map (fromMaybe Unknown . readMaybe)
(sort (map status bats))
acst = mostCommonDef Unknown $ filter (Unknown/=) statuses
racst | acst /= Unknown = acst
| time == 0 = Idle
| ac = Charging
| otherwise = Discharging
unless ac (maybeAlert opts left)
return $ if isNaN left then NA else Result left watts time racst