1 files changed, 78 insertions, 0 deletions
diff --git a/RegUtils.hs b/RegUtils.hs
new file mode 100644
index 0000000..677e4f8
--- /dev/null
+++ b/RegUtils.hs
@@ -0,0 +1,78 @@
+{-
+ - 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.C.String ( peekCWString, withCWString )
+import Foreign.ForeignPtr ( withForeignPtr )
+import Foreign.Marshal.Alloc ( alloca, allocaBytes )
+import Foreign.Ptr ( castPtr, plusPtr )
+import Foreign.Storable ( peek, poke, sizeOf )
+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 $ \keyPtr ->
+  withCWString valueName $ \valueNamePtr ->
+  alloca $ \typePtr -> do
+    ret <- c_RegQueryValueEx keyPtr valueNamePtr nullPtr typePtr nullPtr nullPtr
+    case ret of
+      0x0 -> do
+        type' <- peek typePtr
+        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 $ \keyPtr ->
+  withCWString valueName $ \valueNamePtr ->
+  alloca $ \dataSizePtr -> do
+    poke dataSizePtr 0
+    ret <- c_RegQueryValueEx keyPtr valueNamePtr 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 keyPtr valueNamePtr nullPtr nullPtr dataPtr dataSizePtr
+          peekCWString $ 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 ->
+  withTStringLen valueValue $ \(ptr, len) -> do
+    type' <- getType key subKeyPath valueName
+    regSetValueEx subKey valueName (fromMaybe rEG_SZ type') ptr $ len * sizeOf (undefined :: TCHAR)
+
+delValue :: HKEY -> String -> String -> IO ()
+delValue key subKeyPath valueName =
+  bracket (regOpenKey key subKeyPath) regCloseKey $ \subKey ->
+  withForeignPtr subKey $ \subKeyPtr ->
+  withCWString valueName $ \valueNamePtr -> do
+    ret <- c_RegDeleteValue subKeyPtr valueNamePtr
+    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