63 lines
1.4 KiB
Haskell
Executable file
63 lines
1.4 KiB
Haskell
Executable file
{- portable environment variables
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-
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- Copyright 2013 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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{-# LANGUAGE CPP #-}
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module Utility.Env where
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#ifdef __WINDOWS__
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import Utility.Exception
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import qualified System.Environment as E
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#else
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import qualified System.Posix.Env as PE
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#endif
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{- Posix getEnv is faster than the one in System.Environment,
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- so use when available. -}
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getEnv :: String -> IO (Maybe String)
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#ifndef __WINDOWS__
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getEnv = PE.getEnv
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#else
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getEnv = catchMaybeIO . E.getEnv
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#endif
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getEnvDefault :: String -> String -> IO String
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#ifndef __WINDOWS__
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getEnvDefault = PE.getEnvDefault
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#else
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getEnvDefault var fallback = fromMaybe fallback <$> getEnv var
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#endif
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getEnvironment :: IO [(String, String)]
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#ifndef __WINDOWS__
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getEnvironment = PE.getEnvironment
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#else
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getEnvironment = E.getEnvironment
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#endif
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{- Returns True if it could successfully set the environment variable.
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-
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- There is, apparently, no way to do this in Windows. Instead,
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- environment varuables must be provided when running a new process. -}
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setEnv :: String -> String -> Bool -> IO Bool
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#ifndef __WINDOWS__
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setEnv var val overwrite = do
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PE.setEnv var val overwrite
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return True
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#else
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setEnv _ _ _ = return False
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#endif
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{- Returns True if it could successfully unset the environment variable. -}
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unsetEnv :: String -> IO Bool
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#ifndef __WINDOWS__
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unsetEnv var = do
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PE.unsetEnv var
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return True
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#else
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unsetEnv _ _ _ = return False
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#endif
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