diff options
| author | Joey Hess <joeyh@debian.org> | 2014-07-09 22:11:31 -0400 |
|---|---|---|
| committer | Joey Hess <joeyh@debian.org> | 2014-07-09 22:11:31 -0400 |
| commit | 82da31b3e0e9acdfbca4c48eb12ab1f28515ba10 (patch) | |
| tree | 0a3e0c6e134680e35665364b2cd6895863bcc990 /src/Utility/Env.hs | |
propellor (0.8.1) unstable; urgency=medium
* Run apt-get update in initial bootstrap.
* --list-fields now includes a table of fields that are not currently set,
but would be used if they got set.
* Remove .gitignore from cabal file list, to avoid build failure on Debian.
Closes: #754334
# imported from the archive
Diffstat (limited to 'src/Utility/Env.hs')
| -rw-r--r-- | src/Utility/Env.hs | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/src/Utility/Env.hs b/src/Utility/Env.hs new file mode 100644 index 00000000..6763c24e --- /dev/null +++ b/src/Utility/Env.hs @@ -0,0 +1,81 @@ +{- portable environment variables + - + - Copyright 2013 Joey Hess <joey@kitenet.net> + - + - License: BSD-2-clause + -} + +{-# 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 + +{- Adds the environment variable to the input environment. If already + - present in the list, removes the old value. + - + - This does not really belong here, but Data.AssocList is for some reason + - buried inside hxt. + -} +addEntry :: Eq k => k -> v -> [(k, v)] -> [(k, v)] +addEntry k v l = ( (k,v) : ) $! delEntry k l + +addEntries :: Eq k => [(k, v)] -> [(k, v)] -> [(k, v)] +addEntries = foldr (.) id . map (uncurry addEntry) . reverse + +delEntry :: Eq k => k -> [(k, v)] -> [(k, v)] +delEntry _ [] = [] +delEntry k (x@(k1,_) : rest) + | k == k1 = rest + | otherwise = ( x : ) $! delEntry k rest |
