System/Posix/Error.hs

#if __GLASGOW_HASKELL__ >= 701
{-# LANGUAGE Trustworthy #-}
#endif
-----------------------------------------------------------------------------
-- |
-- Module : System.Posix.Error
-- Copyright : (c) The University of Glasgow 2002
-- License : BSD-style (see the file libraries/base/LICENSE)
-- 
-- Maintainer : libraries@haskell.org
-- Stability : provisional
-- Portability : non-portable (requires POSIX)
--
-- POSIX error support
--
-----------------------------------------------------------------------------

module System.Posix.Error (
	throwErrnoPath,
	throwErrnoPathIf, 
	throwErrnoPathIf_,
 throwErrnoPathIfRetry,
	throwErrnoPathIfNull,
	throwErrnoPathIfNullRetry,
	throwErrnoPathIfMinus1,
	throwErrnoPathIfMinus1_,
 throwErrnoPathIfMinus1Retry,
 throwErrnoPathIfMinus1Retry_
 ) where

import Foreign hiding (void)
import Foreign.C
import Control.Monad

throwErrnoPathIfMinus1Retry :: (Eq a, Num a)
 => String -> FilePath -> IO a -> IO a
throwErrnoPathIfMinus1Retry loc path f =
 throwErrnoPathIfRetry (== -1) loc path f

throwErrnoPathIfMinus1Retry_ :: (Eq a, Num a)
 => String -> FilePath -> IO a -> IO ()
throwErrnoPathIfMinus1Retry_ loc path f =
 void $ throwErrnoPathIfRetry (== -1) loc path f

throwErrnoPathIfNullRetry :: String -> FilePath -> IO (Ptr a) -> IO (Ptr a)
throwErrnoPathIfNullRetry loc path f =
 throwErrnoPathIfRetry (== nullPtr) loc path f

throwErrnoPathIfRetry :: (a -> Bool) -> String -> FilePath -> IO a -> IO a
throwErrnoPathIfRetry pr loc path f =
 do
 res <- f
 if pr res
 then do
 err <- getErrno
 if err == eINTR
 then throwErrnoPathIfRetry pr loc path f
 else throwErrnoPath loc path
 else return res