splitting-up-errors.hs

{-# LANGUAGE PatternGuards, DeriveDataTypeable #-}

module Control.Exception.IOErrors where

import Data.Typeable
import Control.Exception
import System.IO.Error

data AlreadyExists = AlreadyExists IOError deriving Typeable

instance Show AlreadyExists where
  show (AlreadyExists e) = show e

instance Exception AlreadyExists where
  toException (AlreadyExists e) = toException e
  fromException (SomeException e)
    | Just ioe <- cast e,
      isAlreadyExistsError ioe = Just (AlreadyExists ioe)
    | otherwise                = Nothing

data DoesNotExist = DoesNotExist IOError deriving Typeable

instance Show DoesNotExist where
  show (DoesNotExist e) = show e

instance Exception DoesNotExist where
  toException (DoesNotExist e) = toException e
  fromException (SomeException e)
    | Just ioe <- cast e,
      isDoesNotExistError ioe = Just (DoesNotExist ioe)
    | otherwise               = Nothing

data AlreadyInUse = AlreadyInUse IOError deriving Typeable

instance Show AlreadyInUse where
  show (AlreadyInUse e) = show e

instance Exception AlreadyInUse where
  toException (AlreadyInUse e) = toException e
  fromException (SomeException e)
    | Just ioe <- cast e,
      isAlreadyInUseError ioe = Just (AlreadyInUse ioe)
    | otherwise               = Nothing

data DeviceFull = DeviceFull IOError deriving Typeable

instance Show DeviceFull where
  show (DeviceFull e) = show e

instance Exception DeviceFull where
  toException (DeviceFull e) = toException e
  fromException (SomeException e)
    | Just ioe <- cast e,
      isFullError ioe = Just (DeviceFull ioe)
    | otherwise       = Nothing

data EndOfFile = EndOfFile IOError deriving Typeable

instance Show EndOfFile where
  show (EndOfFile e) = show e

instance Exception EndOfFile where
  toException (EndOfFile e) = toException e
  fromException (SomeException e)
    | Just ioe <- cast e,
      isEOFError ioe = Just (EndOfFile ioe)
    | otherwise      = Nothing

data IllegalOperation = IllegalOperation IOError deriving Typeable

instance Show IllegalOperation where
  show (IllegalOperation e) = show e

instance Exception IllegalOperation where
  toException (IllegalOperation e) = toException e
  fromException (SomeException e)
    | Just ioe <- cast e,
      isIllegalOperation ioe = Just (IllegalOperation ioe)
    | otherwise              = Nothing

data PermissionError = PermissionError IOError deriving Typeable

instance Show PermissionError where
  show (PermissionError e) = show e

instance Exception PermissionError where
  toException (PermissionError e) = toException e
  fromException (SomeException e)
    | Just ioe <- cast e,
      isPermissionError ioe = Just (PermissionError ioe)
    | otherwise             = Nothing

data UserError = UserError IOError deriving Typeable

instance Show UserError where
  show (UserError e) = show e

instance Exception UserError where
  toException (UserError e) = toException e
  fromException (SomeException e)
    | Just ioe <- cast e,
      isUserError ioe = Just (UserError ioe)
    | otherwise       = Nothing