From 4d1402a1a7d87767267d48a77998e4fb13395b31 Mon Sep 17 00:00:00 2001
From: Pavan Rikhi <pavan.rikhi@gmail.com>
Date: Sat, 17 Mar 2018 22:48:24 -0400
Subject: Split Modules into Library & Executable Structure

Move the Main module to a new `app` directory. All other modules have
been nested under the `Xmobar` name. Lots of module headers & imports
were updated.
---
 src/Xmobar/Plugins/PipeReader.hs | 47 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 src/Xmobar/Plugins/PipeReader.hs

(limited to 'src/Xmobar/Plugins/PipeReader.hs')

diff --git a/src/Xmobar/Plugins/PipeReader.hs b/src/Xmobar/Plugins/PipeReader.hs
new file mode 100644
index 0000000..7166163
--- /dev/null
+++ b/src/Xmobar/Plugins/PipeReader.hs
@@ -0,0 +1,47 @@
+-----------------------------------------------------------------------------
+-- |
+-- 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 where
+
+import System.IO
+import Xmobar.Plugins
+import Xmobar.Environment
+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
-- 
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