add StatFS.hsc, copied from xmobar

.gitignore

@@ -12,3 +12,4 @@ html
 *.tix
 .hpc
 Touch.hs
+StatFS.hs

StatFS.hsc

@@ -0,0 +1,109 @@
+-----------------------------------------------------------------------------
+-- |
+--
+-- (This code comes from xmobar)
+-- 
+-- Module      :  StatFS
+-- Copyright   :  (c) Jose A Ortega Ruiz
+-- License     :  BSD-3-clause
+--
+-- All rights reserved.
+-- 
+-- Redistribution and use in source and binary forms, with or without
+-- modification, are permitted provided that the following conditions
+-- are met:
+-- 
+-- 1. Redistributions of source code must retain the above copyright
+--    notice, this list of conditions and the following disclaimer.
+-- 2. Redistributions in binary form must reproduce the above copyright
+--    notice, this list of conditions and the following disclaimer in the
+--    documentation and/or other materials provided with the distribution.
+-- 3. Neither the name of the author nor the names of his contributors
+--    may be used to endorse or promote products derived from this software
+--    without specific prior written permission.
+-- 
+-- THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+-- ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+-- ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+-- FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+-- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+-- OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+-- HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+-- LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+-- OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+-- SUCH DAMAGE.
+--
+-- Maintainer  :  Jose A Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+--  A binding to C's statvfs(2)
+--
+-----------------------------------------------------------------------------
+
+{-# LANGUAGE CPP, ForeignFunctionInterface, EmptyDataDecls #-}
+
+
+module StatFS ( FileSystemStats(..), getFileSystemStats ) where
+
+import Foreign
+import Foreign.C.Types
+import Foreign.C.String
+import Data.ByteString (useAsCString)
+import Data.ByteString.Char8 (pack)
+
+#if defined (__FreeBSD__)
+# include <sys/param.h>
+# include <sys/mount.h>
+#else
+#include <sys/vfs.h>
+#endif
+
+data FileSystemStats = FileSystemStats {
+  fsStatBlockSize :: Integer
+  -- ^ Optimal transfer block size.
+  , fsStatBlockCount :: Integer
+  -- ^ Total data blocks in file system.
+  , fsStatByteCount :: Integer
+  -- ^ Total bytes in file system.
+  , fsStatBytesFree :: Integer
+  -- ^ Free bytes in file system.
+  , fsStatBytesAvailable :: Integer
+  -- ^ Free bytes available to non-superusers.
+  , fsStatBytesUsed :: Integer
+  -- ^ Bytes used.
+  } deriving (Show, Eq)
+
+data CStatfs
+
+#if defined(__FreeBSD__)
+foreign import ccall unsafe "sys/mount.h statfs"
+#else
+foreign import ccall unsafe "sys/vfs.h statfs64"
+#endif
+  c_statfs :: CString -> Ptr CStatfs -> IO CInt
+
+toI :: CLong -> Integer
+toI = toInteger
+
+getFileSystemStats :: String -> IO (Maybe FileSystemStats)
+getFileSystemStats path =
+  allocaBytes (#size struct statfs) $ \vfs ->
+  useAsCString (pack path) $ \cpath -> do
+    res <- c_statfs cpath vfs
+    if res == -1 then return Nothing
+      else do
+        bsize <- (#peek struct statfs, f_bsize) vfs
+        bcount <- (#peek struct statfs, f_blocks) vfs
+        bfree <- (#peek struct statfs, f_bfree) vfs
+        bavail <- (#peek struct statfs, f_bavail) vfs
+        let bpb = toI bsize
+        return $ Just FileSystemStats
+                       { fsStatBlockSize = bpb
+                       , fsStatBlockCount = toI bcount
+                       , fsStatByteCount = toI bcount * bpb
+                       , fsStatBytesFree = toI bfree * bpb
+                       , fsStatBytesAvailable = toI bavail * bpb
+                       , fsStatBytesUsed = toI (bcount - bfree) * bpb
+                       }

debian/copyright

@@ -7,3 +7,7 @@ License: GPL-3+
  The full text of version 3 of the GPL is distributed as doc/GPL in
  this package's source, or in /usr/share/common-licenses/GPL-3 on
  Debian systems.
+
+Files: StatFS.hsc
+Copyright: Jose A Ortega Ruiz <jao@gnu.org>
+License: BSD-3-clause