Parameter.hs


{- |
Copyright  : Will Thompson, Iñaki García Etxebarria and Jonas Platte
License    : LGPL-2.1
Maintainer : Iñaki García Etxebarria (garetxe@gmail.com)

The GParameter struct is an auxiliary structure used
to hand parameter name/value pairs to g_object_newv().
-}

module GI.GObject.Structs.Parameter
    ( 

-- * Exported types
    Parameter(..)                           ,
    newZeroParameter                        ,
    noParameter                             ,


 -- * Properties
-- ** Name
    parameterReadName                       ,


-- ** Value
    parameterReadValue                      ,




    ) where

import Prelude ()
import Data.GI.Base.ShortPrelude

import qualified Data.Text as T
import qualified Data.ByteString.Char8 as B
import qualified Data.Map as Map

import GI.GObject.Types
import GI.GObject.Callbacks

newtype Parameter = Parameter (ForeignPtr Parameter)
-- | Construct a `Parameter` struct initialized to zero.
newZeroParameter :: MonadIO m => m Parameter
newZeroParameter = liftIO $ callocBytes 32 >>= wrapPtr Parameter

noParameter :: Maybe Parameter
noParameter = Nothing

parameterReadName :: Parameter -> IO T.Text
parameterReadName s = withManagedPtr s $ \ptr -> do
    val <- peek (ptr `plusPtr` 0) :: IO CString
    val' <- cstringToText val
    return val'

parameterReadValue :: Parameter -> IO GValue
parameterReadValue s = withManagedPtr s $ \ptr -> do
    val <- peek (ptr `plusPtr` 8) :: IO (Ptr GValue)
    val' <- (newBoxed GValue) val
    return val'

type family ResolveParameterMethod (t :: Symbol) (o :: *) :: * where
    ResolveParameterMethod l o = MethodResolutionFailed l o

instance (info ~ ResolveParameterMethod t Parameter, MethodInfo info Parameter p) => IsLabelProxy t (Parameter -> p) where
    fromLabelProxy _ = overloadedMethod (MethodProxy :: MethodProxy info)

#if MIN_VERSION_base(4,9,0)
instance (info ~ ResolveParameterMethod t Parameter, MethodInfo info Parameter p) => IsLabel t (Parameter -> p) where
    fromLabel _ = overloadedMethod (MethodProxy :: MethodProxy info)
#endif