1 files changed, 88 insertions, 0 deletions
diff --git a/src/Windows/Environment.hs b/src/Windows/Environment.hs
new file mode 100644
index 0000000..2bea481
--- /dev/null
+++ b/src/Windows/Environment.hs
@@ -0,0 +1,88 @@
+{-
+ - 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 Windows.Environment
+    ( Profile(..)
+    , profileKeyPath
+
+    , VarName
+    , VarValue
+    , query
+    , engrave
+    , wipe
+
+    , pathJoin
+    , pathSplit
+    ) where
+
+import Data.List       (intercalate)
+import Data.List.Split (splitOn)
+import System.IO.Error (catchIOError, isDoesNotExistError)
+
+import qualified Windows.Registry as Registry
+import           Windows.Utils (notifyEnvironmentUpdate)
+
+data Profile = CurrentUser
+             | AllUsers
+             deriving (Eq, Show)
+
+profileRootKey :: Profile -> Registry.RootKey
+profileRootKey CurrentUser = Registry.CurrentUser
+profileRootKey AllUsers    = Registry.LocalMachine
+
+profileRootKeyPath :: Profile -> Registry.KeyPath
+profileRootKeyPath = Registry.rootKeyPath . profileRootKey
+
+profileSubKeyPath :: Profile -> Registry.KeyPath
+profileSubKeyPath CurrentUser =
+    Registry.keyPathFromString "Environment"
+profileSubKeyPath AllUsers =
+    Registry.keyPathFromString "SYSTEM\\CurrentControlSet\\Control\\Session Manager\\Environment"
+
+profileKeyPath :: Profile -> Registry.KeyPath
+profileKeyPath profile = Registry.keyPathJoin
+    [ profileRootKeyPath profile
+    , profileSubKeyPath  profile
+    ]
+
+openRootProfileKey :: Profile -> Registry.KeyHandle
+openRootProfileKey = Registry.openRootKey . profileRootKey
+
+openProfileKey :: Profile -> IO Registry.KeyHandle
+openProfileKey profile = Registry.openSubKey (openRootProfileKey profile) (profileSubKeyPath profile)
+
+type VarName  = Registry.ValueName
+type VarValue = Registry.ValueData
+
+query :: Profile -> VarName -> IO (Maybe VarValue)
+query profile name = do
+    keyHandle <- openProfileKey profile
+    catchIOError (Registry.getString keyHandle name >>= return . Just) emptyIfDoesNotExist
+  where
+    emptyIfDoesNotExist e = if isDoesNotExistError e then return Nothing else ioError e
+
+engrave :: Profile -> VarName -> VarValue -> IO ()
+engrave profile name value = do
+    keyHandle <- openProfileKey profile
+    Registry.setString keyHandle name value
+    notifyEnvironmentUpdate
+
+wipe :: Profile -> VarName -> IO ()
+wipe profile name = do
+    keyHandle <- openProfileKey profile
+    catchIOError (Registry.delValue keyHandle name) ignoreIfDoesNotExist
+    notifyEnvironmentUpdate
+  where
+    ignoreIfDoesNotExist e = if isDoesNotExistError e then return () else ioError e
+
+pathSep :: VarValue
+pathSep = ";"
+
+pathSplit :: VarValue -> [VarValue]
+pathSplit = filter (not . null) . splitOn pathSep
+
+pathJoin :: [VarValue] -> VarValue
+pathJoin = intercalate pathSep . filter (not . null)