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authorjao <jao@gnu.org>2018-11-25 15:10:29 +0000
committerjao <jao@gnu.org>2018-11-25 15:10:29 +0000
commit77df1ac30fa7af5948f7ff64f5fee9aed64552b3 (patch)
tree647a4eb67ff1c293a5c530538ee88fc0093b577a /src/Xmobar/Plugins/PipeReader.hs
parente0d6da82de8d0d1cef98896164c6016b84e47068 (diff)
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Back to app/src, since it seems they're the default convention for stack
Diffstat (limited to 'src/Xmobar/Plugins/PipeReader.hs')
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diff --git a/src/Xmobar/Plugins/PipeReader.hs b/src/Xmobar/Plugins/PipeReader.hs
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+-----------------------------------------------------------------------------
+-- |
+-- Module : Plugins.PipeReader
+-- Copyright : (c) Andrea Rossato
+-- License : BSD-style (see LICENSE)
+--
+-- Maintainer : Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability : unstable
+-- Portability : unportable
+--
+-- A plugin for reading from named pipes
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.PipeReader(PipeReader(..)) where
+
+import System.IO
+import Xmobar.Utils(hGetLineSafe)
+import Xmobar.Run.Commands(Exec(..))
+import Xmobar.System.Environment(expandEnv)
+import System.Posix.Files
+import Control.Concurrent(threadDelay)
+import Control.Exception
+import Control.Monad(forever, unless)
+import Control.Applicative ((<$>))
+
+data PipeReader = PipeReader String String
+ deriving (Read, Show)
+
+instance Exec PipeReader where
+ alias (PipeReader _ a) = a
+ start (PipeReader p _) cb = do
+ (def, pipe) <- split ':' <$> expandEnv p
+ unless (null def) (cb def)
+ checkPipe pipe
+ h <- openFile pipe ReadWriteMode
+ forever (hGetLineSafe h >>= cb)
+ where
+ split c xs | c `elem` xs = let (pre, post) = span (c /=) xs
+ in (pre, dropWhile (c ==) post)
+ | otherwise = ([], xs)
+
+checkPipe :: FilePath -> IO ()
+checkPipe file =
+ handle (\(SomeException _) -> waitForPipe) $ do
+ status <- getFileStatus file
+ unless (isNamedPipe status) waitForPipe
+ where waitForPipe = threadDelay 1000000 >> checkPipe file