-{-# OPTIONS -fno-implicit-prelude -#include "HsBase.h" #-}
+{-# OPTIONS_GHC -fno-implicit-prelude -#include "HsBase.h" #-}
-----------------------------------------------------------------------------
-- |
-- Module : Foreign.C.Error
-- Stability : provisional
-- Portability : portable
--
--- C-specific Marshalling support: Handling of C \"errno\" error codes
+-- C-specific Marshalling support: Handling of C \"errno\" error codes.
--
-----------------------------------------------------------------------------
module Foreign.C.Error (
- -- Haskell representation for "errno" values
- --
+ -- * Haskell representations of @errno@ values
+
Errno(..), -- instance: Eq
+
+ -- ** Common @errno@ symbols
+ -- | Different operating systems and\/or C libraries often support
+ -- different values of @errno@. This module defines the common values,
+ -- but due to the open definition of 'Errno' users may add definitions
+ -- which are not predefined.
eOK, e2BIG, eACCES, eADDRINUSE, eADDRNOTAVAIL, eADV, eAFNOSUPPORT, eAGAIN,
eALREADY, eBADF, eBADMSG, eBADRPC, eBUSY, eCHILD, eCOMM, eCONNABORTED,
eCONNREFUSED, eCONNRESET, eDEADLK, eDESTADDRREQ, eDIRTY, eDOM, eDQUOT,
eRANGE, eREMCHG, eREMOTE, eROFS, eRPCMISMATCH, eRREMOTE, eSHUTDOWN,
eSOCKTNOSUPPORT, eSPIPE, eSRCH, eSRMNT, eSTALE, eTIME, eTIMEDOUT,
eTOOMANYREFS, eTXTBSY, eUSERS, eWOULDBLOCK, eXDEV,
+
+ -- ** 'Errno' functions
-- :: Errno
isValidErrno, -- :: Errno -> Bool
--
throwErrno, -- :: String -> IO a
- -- guards for IO operations that may fail
- --
+ -- ** Guards for IO operations that may fail
+
throwErrnoIf, -- :: (a -> Bool) -> String -> IO a -> IO a
throwErrnoIf_, -- :: (a -> Bool) -> String -> IO a -> IO ()
throwErrnoIfRetry, -- :: (a -> Bool) -> String -> IO a -> IO a
-- calculated for us
--
#ifndef __NHC__
-#include "config.h"
+#include "HsBaseConfig.h"
#endif
-- system dependent imports
import GHC.IOBase
import GHC.Num
import GHC.Base
+#elif __HUGS__
+import Hugs.Prelude ( Handle, IOError, ioError )
+import System.IO.Unsafe ( unsafePerformIO )
#else
-import System.IO ( IOError, Handle, ioError )
+import System.IO ( Handle )
+import System.IO.Error ( IOError, ioError )
import System.IO.Unsafe ( unsafePerformIO )
#endif
#ifdef __HUGS__
-{-# CBITS errno.c #-}
+{-# CFILES cbits/PrelIOUtils.c #-}
#endif
-- "errno" type
-- ------------
--- Haskell representation for "errno" values
---
+-- | Haskell representation for @errno@ values.
+-- The implementation is deliberately exposed, to allow users to add
+-- their own definitions of 'Errno' values.
+
newtype Errno = Errno CInt
instance Eq Errno where
eXDEV = Errno (CONST_EXDEV)
#endif
--- checks whether the given errno value is supported on the current
--- architecture
+-- | Yield 'True' if the given 'Errno' value is valid on the system.
+-- This implies that the 'Eq' instance of 'Errno' is also system dependent
+-- as it is only defined for valid values of 'Errno'.
--
isValidErrno :: Errno -> Bool
--
-- access to the current thread's "errno" value
-- --------------------------------------------
--- yield the current thread's "errno" value
+-- | Get the current value of @errno@ in the current thread.
--
getErrno :: IO Errno
-- thread gets its own copy.
#ifdef __NHC__
getErrno = do e <- peek _errno; return (Errno e)
-foreign import ccall unsafe "errno.h &errno" _errno :: IO (Ptr CInt)
+foreign import ccall unsafe "errno.h &errno" _errno :: Ptr CInt
#else
getErrno = do e <- get_errno; return (Errno e)
foreign import ccall unsafe "HsBase.h __hscore_get_errno" get_errno :: IO CInt
#endif
--- set the current thread's "errno" value to 0
+-- | Reset the current thread\'s @errno@ value to 'eOK'.
--
resetErrno :: IO ()
-- throw current "errno" value
-- ---------------------------
--- the common case: throw an IO error based on a textual description
--- of the error location and the current thread's "errno" value
+-- | Throw an 'IOError' corresponding to the current value of 'getErrno'.
--
-throwErrno :: String -> IO a
+throwErrno :: String -- ^ textual description of the error location
+ -> IO a
throwErrno loc =
do
errno <- getErrno
-- guards for IO operations that may fail
-- --------------------------------------
--- guard an IO operation and throw an "errno" based exception of the result
--- value of the IO operation meets the given predicate
+-- | Throw an 'IOError' corresponding to the current value of 'getErrno'
+-- if the result value of the 'IO' action meets the given predicate.
--
-throwErrnoIf :: (a -> Bool) -> String -> IO a -> IO a
+throwErrnoIf :: (a -> Bool) -- ^ predicate to apply to the result value
+ -- of the 'IO' operation
+ -> String -- ^ textual description of the location
+ -> IO a -- ^ the 'IO' operation to be executed
+ -> IO a
throwErrnoIf pred loc f =
do
res <- f
if pred res then throwErrno loc else return res
--- as `throwErrnoIf', but discards the result
+-- | as 'throwErrnoIf', but discards the result of the 'IO' action after
+-- error handling.
--
-throwErrnoIf_ :: (a -> Bool) -> String -> IO a -> IO ()
+throwErrnoIf_ :: (a -> Bool) -> String -> IO a -> IO ()
throwErrnoIf_ pred loc f = void $ throwErrnoIf pred loc f
--- as `throwErrnoIf', but retries interrupted IO operations (ie, those whose
--- flag `EINTR')
+-- | as 'throwErrnoIf', but retry the 'IO' action when it yields the
+-- error code 'eINTR' - this amounts to the standard retry loop for
+-- interrupted POSIX system calls.
--
throwErrnoIfRetry :: (a -> Bool) -> String -> IO a -> IO a
throwErrnoIfRetry pred loc f =
else throwErrno loc
else return res
--- as `throwErrnoIfRetry', but checks for operations that would block and
--- executes an alternative action in that case.
-
-throwErrnoIfRetryMayBlock :: (a -> Bool) -> String -> IO a -> IO b -> IO a
+-- | as 'throwErrnoIfRetry', but checks for operations that would block and
+-- executes an alternative action before retrying in that case.
+--
+throwErrnoIfRetryMayBlock
+ :: (a -> Bool) -- ^ predicate to apply to the result value
+ -- of the 'IO' operation
+ -> String -- ^ textual description of the location
+ -> IO a -- ^ the 'IO' operation to be executed
+ -> IO b -- ^ action to execute before retrying if
+ -- an immediate retry would block
+ -> IO a
throwErrnoIfRetryMayBlock pred loc f on_block =
do
res <- f
else throwErrno loc
else return res
--- as `throwErrnoIfRetry', but discards the result
+-- | as 'throwErrnoIfRetry', but discards the result.
--
throwErrnoIfRetry_ :: (a -> Bool) -> String -> IO a -> IO ()
throwErrnoIfRetry_ pred loc f = void $ throwErrnoIfRetry pred loc f
--- as `throwErrnoIfRetryMayBlock', but discards the result
+-- | as 'throwErrnoIfRetryMayBlock', but discards the result.
--
throwErrnoIfRetryMayBlock_ :: (a -> Bool) -> String -> IO a -> IO b -> IO ()
throwErrnoIfRetryMayBlock_ pred loc f on_block
= void $ throwErrnoIfRetryMayBlock pred loc f on_block
--- throws "errno" if a result of "-1" is returned
+-- | Throw an 'IOError' corresponding to the current value of 'getErrno'
+-- if the 'IO' action returns a result of @-1@.
--
throwErrnoIfMinus1 :: Num a => String -> IO a -> IO a
throwErrnoIfMinus1 = throwErrnoIf (== -1)
--- as `throwErrnoIfMinus1', but discards the result
+-- | as 'throwErrnoIfMinus1', but discards the result.
--
throwErrnoIfMinus1_ :: Num a => String -> IO a -> IO ()
throwErrnoIfMinus1_ = throwErrnoIf_ (== -1)
--- throws "errno" if a result of "-1" is returned, but retries in case of an
--- interrupted operation
+-- | Throw an 'IOError' corresponding to the current value of 'getErrno'
+-- if the 'IO' action returns a result of @-1@, but retries in case of
+-- an interrupted operation.
--
throwErrnoIfMinus1Retry :: Num a => String -> IO a -> IO a
throwErrnoIfMinus1Retry = throwErrnoIfRetry (== -1)
--- as `throwErrnoIfMinus1', but discards the result
+-- | as 'throwErrnoIfMinus1', but discards the result.
--
throwErrnoIfMinus1Retry_ :: Num a => String -> IO a -> IO ()
throwErrnoIfMinus1Retry_ = throwErrnoIfRetry_ (== -1)
--- as throwErrnoIfMinus1Retry, but checks for operations that would block
+-- | as 'throwErrnoIfMinus1Retry', but checks for operations that would block.
--
throwErrnoIfMinus1RetryMayBlock :: Num a => String -> IO a -> IO b -> IO a
throwErrnoIfMinus1RetryMayBlock = throwErrnoIfRetryMayBlock (== -1)
--- as `throwErrnoIfMinus1RetryMayBlock', but discards the result
+-- | as 'throwErrnoIfMinus1RetryMayBlock', but discards the result.
--
throwErrnoIfMinus1RetryMayBlock_ :: Num a => String -> IO a -> IO b -> IO ()
throwErrnoIfMinus1RetryMayBlock_ = throwErrnoIfRetryMayBlock_ (== -1)
--- throws "errno" if a result of a NULL pointer is returned
+-- | Throw an 'IOError' corresponding to the current value of 'getErrno'
+-- if the 'IO' action returns 'nullPtr'.
--
throwErrnoIfNull :: String -> IO (Ptr a) -> IO (Ptr a)
throwErrnoIfNull = throwErrnoIf (== nullPtr)
--- throws "errno" if a result of a NULL pointer is returned, but retries in
--- case of an interrupted operation
+-- | Throw an 'IOError' corresponding to the current value of 'getErrno'
+-- if the 'IO' action returns 'nullPtr',
+-- but retry in case of an interrupted operation.
--
throwErrnoIfNullRetry :: String -> IO (Ptr a) -> IO (Ptr a)
throwErrnoIfNullRetry = throwErrnoIfRetry (== nullPtr)
--- as throwErrnoIfNullRetry, but checks for operations that would block
+-- | as 'throwErrnoIfNullRetry', but checks for operations that would block.
--
throwErrnoIfNullRetryMayBlock :: String -> IO (Ptr a) -> IO b -> IO (Ptr a)
throwErrnoIfNullRetryMayBlock = throwErrnoIfRetryMayBlock (== nullPtr)
+-- | as 'throwErrno', but exceptions include the given path when appropriate.
+--
+throwErrnoPath :: String -> FilePath -> IO a
+throwErrnoPath loc path =
+ do
+ errno <- getErrno
+ ioError (errnoToIOError loc errno Nothing (Just path))
+
+-- | as 'throwErrnoIf', but exceptions include the given path when
+-- appropriate.
+--
+throwErrnoPathIf :: (a -> Bool) -> String -> FilePath -> IO a -> IO a
+throwErrnoPathIf pred loc path f =
+ do
+ res <- f
+ if pred res then throwErrnoPath loc path else return res
+
+-- | as 'throwErrnoIf_', but exceptions include the given path when
+-- appropriate.
+--
+throwErrnoPathIf_ :: (a -> Bool) -> String -> FilePath -> IO a -> IO ()
+throwErrnoPathIf_ pred loc path f = void $ throwErrnoPathIf pred loc path f
+
+-- | as 'throwErrnoIfNull', but exceptions include the given path when
+-- appropriate.
+--
+throwErrnoPathIfNull :: String -> FilePath -> IO (Ptr a) -> IO (Ptr a)
+throwErrnoPathIfNull = throwErrnoPathIf (== nullPtr)
+
+-- | as 'throwErrnoIfMinus1', but exceptions include the given path when
+-- appropriate.
+--
+throwErrnoPathIfMinus1 :: Num a => String -> FilePath -> IO a -> IO a
+throwErrnoPathIfMinus1 = throwErrnoPathIf (== -1)
+
+-- | as 'throwErrnoIfMinus1_', but exceptions include the given path when
+-- appropriate.
+--
+throwErrnoPathIfMinus1_ :: Num a => String -> FilePath -> IO a -> IO ()
+throwErrnoPathIfMinus1_ = throwErrnoPathIf_ (== -1)
+
-- conversion of an "errno" value into IO error
-- --------------------------------------------
--- convert a location string, an "errno" value, an optional handle,
--- and an optional filename into a matching IO error
+-- | Construct a Haskell 98 I\/O error based on the given 'Errno' value.
+-- The optional information can be used to improve the accuracy of
+-- error messages.
--
-errnoToIOError :: String -> Errno -> Maybe Handle -> Maybe String -> IOError
+errnoToIOError :: String -- ^ the location where the error occurred
+ -> Errno -- ^ the error number
+ -> Maybe Handle -- ^ optional handle associated with the error
+ -> Maybe String -- ^ optional filename associated with the error
+ -> IOError
errnoToIOError loc errno maybeHdl maybeName = unsafePerformIO $ do
str <- strerror errno >>= peekCString
#if __GLASGOW_HASKELL__
| errno == eAFNOSUPPORT = UnsupportedOperation
| errno == eAGAIN = ResourceExhausted
| errno == eALREADY = AlreadyExists
- | errno == eBADF = OtherError
+ | errno == eBADF = InvalidArgument
| errno == eBADMSG = InappropriateType
| errno == eBADRPC = OtherError
| errno == eBUSY = ResourceBusy
projects / ghc-base.git / blobdiff