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-rw-r--r--EnvUtils.hs81
1 files changed, 81 insertions, 0 deletions
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+{-
+ - Copyright 2015 Egor Tensin <Egor.Tensin@gmail.com>
+ - This file is licensed under the terms of the MIT License.
+ - See LICENSE.txt for details.
+-}
+
+module EnvUtils ( saveToRegistry
+ , saveToRegistryWithPrompt
+ , queryFromRegistry
+ , wipeFromRegistry
+ , wipeFromRegistryWithPrompt
+ , getEnv
+ , splitPaths
+ , joinPaths
+ , RegistryBasedEnvironment ( CurrentUserEnvironment, AllUsersEnvironment ) ) where
+
+import Control.Monad ( liftM, when )
+import Data.List ( intercalate )
+import Data.List.Split ( splitOn )
+import Data.Maybe ( fromMaybe )
+import qualified System.Environment ( lookupEnv )
+import System.IO.Error ( catchIOError, isDoesNotExistError )
+
+import qualified RegUtils
+import qualified Utils ( promptToContinue )
+
+data RegistryBasedEnvironment = CurrentUserEnvironment
+ | AllUsersEnvironment
+ deriving (Eq, Show)
+
+registrySubKeyPath :: RegistryBasedEnvironment -> String
+registrySubKeyPath CurrentUserEnvironment = "Environment"
+registrySubKeyPath AllUsersEnvironment = "SYSTEM\\CurrentControlSet\\Control\\Session Manager\\Environment"
+
+registryKey CurrentUserEnvironment = RegUtils.hkcu
+registryKey AllUsersEnvironment = RegUtils.hklm
+
+registryKeyPath :: RegistryBasedEnvironment -> String
+registryKeyPath CurrentUserEnvironment = "HKCU\\" ++ registrySubKeyPath CurrentUserEnvironment
+registryKeyPath AllUsersEnvironment = "HKLM\\" ++ registrySubKeyPath AllUsersEnvironment
+
+saveToRegistry :: RegistryBasedEnvironment -> String -> String -> IO ()
+saveToRegistry env = RegUtils.setString (registryKey env) (registrySubKeyPath env)
+
+saveToRegistryWithPrompt :: RegistryBasedEnvironment -> String -> String -> IO ()
+saveToRegistryWithPrompt env name value = do
+ putStrLn $ "Saving variable '" ++ name ++ "' to '" ++ registryKeyPath env ++ "'..."
+ oldValue <- queryFromRegistry env name
+ putStrLn $ "\tOld value: " ++ oldValue
+ putStrLn $ "\tNew value: " ++ value
+ agreed <- Utils.promptToContinue
+ when agreed $ saveToRegistry env name value
+
+queryFromRegistry :: RegistryBasedEnvironment -> String -> IO String
+queryFromRegistry env name = catchIOError (RegUtils.getString (registryKey env) (registrySubKeyPath env) name) emptyIfDoesNotExist
+ where
+ emptyIfDoesNotExist :: IOError -> IO String
+ emptyIfDoesNotExist e = if isDoesNotExistError e then return "" else ioError e
+
+wipeFromRegistry :: RegistryBasedEnvironment -> String -> IO ()
+wipeFromRegistry env name = catchIOError (RegUtils.delValue (registryKey env) (registrySubKeyPath env) name) ignoreIfDoesNotExist
+ where
+ ignoreIfDoesNotExist :: IOError -> IO ()
+ ignoreIfDoesNotExist e = if isDoesNotExistError e then return () else ioError e
+
+wipeFromRegistryWithPrompt :: RegistryBasedEnvironment -> String -> IO ()
+wipeFromRegistryWithPrompt env name = do
+ putStrLn $ "Deleting variable '" ++ name ++ "' from '" ++ registryKeyPath env ++ "'..."
+ agreed <- Utils.promptToContinue
+ when agreed $ wipeFromRegistry env name
+
+getEnv :: String -> IO String
+getEnv = liftM (fromMaybe "") . System.Environment.lookupEnv
+
+pathSep = ";"
+
+splitPaths :: String -> [String]
+splitPaths = filter (not . null) . splitOn pathSep
+
+joinPaths :: [String] -> String
+joinPaths = intercalate pathSep . filter (not . null)