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-rw-r--r--src/Xmobar/Plugins/Monitors/Batt/Linux.hs182
1 files changed, 113 insertions, 69 deletions
diff --git a/src/Xmobar/Plugins/Monitors/Batt/Linux.hs b/src/Xmobar/Plugins/Monitors/Batt/Linux.hs
index 362c529..9b53f65 100644
--- a/src/Xmobar/Plugins/Monitors/Batt/Linux.hs
+++ b/src/Xmobar/Plugins/Monitors/Batt/Linux.hs
@@ -24,21 +24,44 @@ import Control.Monad (unless)
import Control.Exception (SomeException, handle)
import System.FilePath ((</>))
import System.IO (IOMode(ReadMode), hGetLine, withFile, Handle)
-import System.Posix.Files (fileExist)
import Data.List (sort, sortBy, group)
import Data.Maybe (fromMaybe)
import Data.Ord (comparing)
import Text.Read (readMaybe)
data Files = Files
- { fFull :: String
- , fNow :: String
+ { fEFull :: String
+ , fCFull :: String
+ , fEFullDesign :: String
+ , fCFullDesign :: String
+ , fENow :: String
+ , fCNow :: String
, fVoltage :: String
, fVoltageMin :: String
- , fCurrent :: Maybe String
- , fPower :: Maybe String
+ , fCurrent :: String
+ , fPower :: String
, fStatus :: String
- } | NoFiles deriving Eq
+ } deriving Eq
+
+-- the default basenames of the possibly available attributes exposed by the kernel
+defFileBasenames :: Files
+defFileBasenames = 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" }
+
+-- prefix all files in a Files object by a given prefix
+-- I couldn't find a better way to do this
+prefixFiles :: String -> Files -> Files
+prefixFiles p (Files a b c d e f g h i j k) = Files (p </> a) (p </> b) (p </> c) (p </> d) (p </> e) (p </> f) (p </> g) (p </> h) (p </> i) (p </> j) (p </> k)
data Battery = Battery
{ full :: !Float
@@ -50,79 +73,101 @@ data Battery = Battery
sysDir :: FilePath
sysDir = "/sys/class/power_supply"
-safeFileExist :: String -> String -> IO Bool
-safeFileExist d f = handle noErrors $ fileExist (d </> f)
- where noErrors = const (return False) :: SomeException -> IO Bool
-
-batteryFiles :: String -> IO Files
-batteryFiles bat =
- do is_charge <- exists "charge_now"
- is_energy <- if is_charge then return False else exists "energy_now"
- plain <- exists (if is_charge then "charge_full" else "energy_full")
- has_power <- exists powerNowPath
- has_current <- exists currentNowPath
- let pf = if has_power then Just powerNowPath else Nothing
- cf = if has_current then Just currentNowPath else Nothing
- sf = if plain then "" else "_design"
- return $ case (is_charge, is_energy) of
- (True, _) -> files "charge" cf pf sf
- (_, True) -> files "energy" cf pf sf
- _ -> NoFiles
- where prefix = sysDir </> bat
- justPrefix a = Just $ prefix </> a
- exists = safeFileExist prefix
- files ch cf pf sf = Files { fFull = prefix </> ch ++ "_full" ++ sf
- , fNow = prefix </> ch ++ "_now"
- , fCurrent = maybe Nothing justPrefix cf
- , fPower = maybe Nothing justPrefix pf
- , fVoltage = prefix </> "voltage_now"
- , fVoltageMin = prefix </> "voltage_min_design"
- , fStatus = prefix </> "status"}
- currentNowPath = "current_now"
- powerNowPath = "power_now"
+-- get the filenames for a given battery name
+batteryFiles :: String -> Files
+batteryFiles bat = prefixFiles (sysDir </> bat) defFileBasenames
haveAc :: FilePath -> IO Bool
haveAc f =
- handle (onError False) $ withFile (sysDir </> f) ReadMode (fmap (== "1") . hGetLine)
-
-readBatPower :: Float -> Files -> IO Float
-
-readBatPower sc (Files {fPower = Just p}) =
- do valp <- grabNumber p
- return $ valp / sc
-
-readBatPower sc (Files {fPower = Nothing, fCurrent = Just c, fVoltage = v}) =
- do valv <- grabNumber v
- valc <- grabNumber c
- return $ valc * valv / (sc * sc)
-
-readBatPower _ _ = do return 999
-
+ 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
+ vM <- grabNumber $ fVoltageMin f -- not sure if Voltage or VoltageMin is more accurate and if both are always available
+ 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 f = grabString $ fStatus f
+
+-- "resolve" a Maybe to a given default value if it is Nothing
+setDefault :: a -> IO (Maybe a) -> IO a
+setDefault def ioval =
+ do m <- ioval
+ return $ case m of (Just v) -> v
+ Nothing -> def
+
+-- collect all relevant battery values with defaults of not available
readBattery :: Float -> Files -> IO Battery
-readBattery _ NoFiles = return $ Battery 0 0 0 "Unknown"
readBattery sc files =
- do a <- grabNumber $ fFull files
- b <- grabNumber $ fNow files
- p <- readBatPower sc files
- s <- grabString $ fStatus files
- let a' = max a b -- sometimes the reported max charge is lower than
- return $ Battery (3600 * a' / sc) -- wattseconds
- (3600 * b / sc) -- wattseconds
- (abs p) -- watts
+ do cFull <- setDefault 0 $ readBatCapacityFull sc files
+ cNow <- setDefault 0 $ readBatCapacityNow sc files
+ pwr <- setDefault 0 $ readBatPower sc files
+ s <- setDefault "Unknown" $ readBatStatus files
+ 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
-grabNumber :: (Num a, Read a) => FilePath -> IO a
-grabNumber = grabFile (-1) (fmap read . hGetLine)
+grabNumber :: (Num a, Read a) => FilePath -> IO (Maybe a)
+grabNumber = grabFile (fmap read . hGetLine)
-grabString :: FilePath -> IO String
-grabString = grabFile "Unknown" hGetLine
+grabString :: FilePath -> IO (Maybe String)
+grabString = grabFile hGetLine
-grabFile :: a -> (Handle -> IO a) -> FilePath -> IO a
-grabFile returnOnError readMode f = handle (onFileError returnOnError) $ withFile f ReadMode readMode
+-- grab file contents returning Nothing if the file doesn't exist or any other error occurs
+grabFile :: (Handle -> IO a) -> FilePath -> IO (Maybe a)
+grabFile readMode f = handle (onFileError Nothing) (withFile f ReadMode (doJust . readMode))
onFileError :: a -> SomeException -> IO a
onFileError returnOnError = const (return returnOnError)
+doJust :: IO a -> IO (Maybe a)
+doJust a =
+ do v <- a
+ return $ Just v
+
-- sortOn is only available starting at ghc 7.10
sortOn :: Ord b => (a -> b) -> [a] -> [a]
sortOn f =
@@ -133,12 +178,11 @@ mostCommonDef x xs = head $ last $ [x] : sortOn length (group xs)
readBatteries :: BattOpts -> [String] -> IO Result
readBatteries opts bfs =
- do bfs' <- mapM batteryFiles bfs
- let bfs'' = filter (/= NoFiles) 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)
+ 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)