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Diffstat (limited to 'Utility/Env.hs')
-rw-r--r-- | Utility/Env.hs | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/Utility/Env.hs b/Utility/Env.hs new file mode 100644 index 0000000..cb73873 --- /dev/null +++ b/Utility/Env.hs @@ -0,0 +1,63 @@ +{- portable environment variables + - + - Copyright 2013 Joey Hess <joey@kitenet.net> + - + - Licensed under the GNU GPL version 3 or higher. + -} + +{-# LANGUAGE CPP #-} + +module Utility.Env where + +#ifdef mingw32_HOST_OS +import Utility.Exception +import Control.Applicative +import Data.Maybe +import qualified System.Environment as E +#else +import qualified System.Posix.Env as PE +#endif + +getEnv :: String -> IO (Maybe String) +#ifndef mingw32_HOST_OS +getEnv = PE.getEnv +#else +getEnv = catchMaybeIO . E.getEnv +#endif + +getEnvDefault :: String -> String -> IO String +#ifndef mingw32_HOST_OS +getEnvDefault = PE.getEnvDefault +#else +getEnvDefault var fallback = fromMaybe fallback <$> getEnv var +#endif + +getEnvironment :: IO [(String, String)] +#ifndef mingw32_HOST_OS +getEnvironment = PE.getEnvironment +#else +getEnvironment = E.getEnvironment +#endif + +{- Returns True if it could successfully set the environment variable. + - + - There is, apparently, no way to do this in Windows. Instead, + - environment varuables must be provided when running a new process. -} +setEnv :: String -> String -> Bool -> IO Bool +#ifndef mingw32_HOST_OS +setEnv var val overwrite = do + PE.setEnv var val overwrite + return True +#else +setEnv _ _ _ = return False +#endif + +{- Returns True if it could successfully unset the environment variable. -} +unsetEnv :: String -> IO Bool +#ifndef mingw32_HOST_OS +unsetEnv var = do + PE.unsetEnv var + return True +#else +unsetEnv _ = return False +#endif |