1 files changed, 91 insertions, 0 deletions
diff --git a/src/RegUtils.hs b/src/RegUtils.hs
new file mode 100644
index 0000000..eccb6ad
--- /dev/null
+++ b/src/RegUtils.hs
@@ -0,0 +1,91 @@
+{-
+ - 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 RegUtils ( delValue
+                , getString
+                , hkcu
+                , hklm
+                , setString ) where
+
+import Control.Exception ( bracket )
+import Data.Maybe ( fromMaybe )
+import Foreign.ForeignPtr ( withForeignPtr )
+import Foreign.Marshal.Alloc ( alloca, allocaBytes )
+import Foreign.Ptr ( castPtr, plusPtr )
+import Foreign.Storable ( peek, poke, sizeOf )
+import Graphics.Win32.Window ( sendMessage )
+import System.IO.Error ( mkIOError, doesNotExistErrorType )
+import System.Win32.Types
+import System.Win32.Registry
+
+getType :: HKEY -> String -> String -> IO (Maybe RegValueType)
+getType key subKeyPath valueName =
+  bracket (regOpenKey key subKeyPath) regCloseKey $ \key ->
+  withForeignPtr key $ \p_key ->
+  withTString valueName $ \p_valueName ->
+  alloca $ \p_type -> do
+    ret <- c_RegQueryValueEx p_key p_valueName nullPtr p_type nullPtr nullPtr
+    case ret of
+      0x0 -> do
+        type_ <- peek p_type
+        return $ Just type_
+      0x2 -> return Nothing
+      _   -> failWith "RegQueryValueEx" ret
+
+getString :: HKEY -> String -> String -> IO String
+getString key subKeyPath valueName =
+  bracket (regOpenKey key subKeyPath) regCloseKey $ \key ->
+  withForeignPtr key $ \p_key ->
+  withTString valueName $ \p_valueName ->
+  alloca $ \dataSizePtr -> do
+    poke dataSizePtr 0
+    ret <- c_RegQueryValueEx p_key p_valueName nullPtr nullPtr nullPtr dataSizePtr
+    case ret of
+      0x0 -> do
+        dataSize <- peek dataSizePtr
+        let newDataSize = dataSize + fromIntegral (sizeOf (undefined :: TCHAR))
+        poke dataSizePtr newDataSize
+        allocaBytes (fromIntegral newDataSize) $ \dataPtr -> do
+          poke (castPtr $ plusPtr dataPtr $ fromIntegral dataSize) '\0'
+          failUnlessSuccess "RegQueryValueEx" $
+            c_RegQueryValueEx p_key p_valueName nullPtr nullPtr dataPtr dataSizePtr
+          peekTString $ castPtr dataPtr
+      0x2 -> ioError $ mkIOError doesNotExistErrorType "RegQueryValueEx" Nothing $ Just (subKeyPath ++ "\\" ++ valueName)
+      _   -> failWith "RegQueryValueEx" ret
+
+setString :: HKEY -> String -> String -> String -> IO ()
+setString key subKeyPath valueName valueValue =
+  bracket (regOpenKey key subKeyPath) regCloseKey $ \subKey ->
+  withTString valueValue $ \p_valueValue -> do
+    type_ <- getType key subKeyPath valueName
+    regSetValueEx subKey valueName (fromMaybe rEG_SZ type_) p_valueValue $ (length valueValue + 1) * sizeOf (undefined :: TCHAR)
+    notifyEnvironmentUpdate
+
+notifyEnvironmentUpdate :: IO ()
+notifyEnvironmentUpdate =
+  withTString "Environment" $ \p_lparam -> do
+    let wparam = 0
+    let lparam = fromIntegral $ castPtrToUINTPtr p_lparam
+    let hwnd = castUINTPtrToPtr 0xffff
+    sendMessage hwnd wM_SETTINGCHANGE wparam lparam
+    return ()
+      where
+        wM_SETTINGCHANGE = 0x1A
+
+delValue :: HKEY -> String -> String -> IO ()
+delValue key subKeyPath valueName =
+  bracket (regOpenKey key subKeyPath) regCloseKey $ \subKey ->
+  withForeignPtr subKey $ \subKeyPtr ->
+  withTString valueName $ \p_valueName -> do
+    ret <- c_RegDeleteValue subKeyPtr p_valueName
+    notifyEnvironmentUpdate
+    case ret of
+      0x0 -> return ()
+      0x2 -> ioError $ mkIOError doesNotExistErrorType "RegQueryValueEx" Nothing $ Just (subKeyPath ++ "\\" ++ valueName)
+      _   -> failWith "RegDeleteValue" ret
+
+hkcu = hKEY_CURRENT_USER
+hklm = hKEY_LOCAL_MACHINE