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|
{-# OPTIONS_HADDOCK hide #-}
-- GIMP Toolkit (GTK) Binding for Haskell: binding to gstreamer -*-haskell-*-
--
-- Author : Peter Gavin
-- Created: 1-Apr-2007
--
-- Copyright (c) 2007 Peter Gavin
--
-- This library is free software: you can redistribute it and/or
-- modify it under the terms of the GNU Lesser General Public License
-- as published by the Free Software Foundation, either version 3 of
-- the License, or (at your option) any later version.
--
-- This library is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-- Lesser General Public License for more details.
--
-- You should have received a copy of the GNU Lesser General Public
-- License along with this program. If not, see
-- <http://www.gnu.org/licenses/>.
--
-- GStreamer, the C library which this Haskell library depends on, is
-- available under LGPL Version 2. The documentation included with
-- this library is based on the original GStreamer documentation.
-- # hide
-- | Maintainer : gtk2hs-devel\@lists.sourceforge.net
-- Stability : alpha
-- Portability : portable (depends on GHC)
module Media.Streaming.GStreamer.Core.HierarchyBase (
mkCastToGObject,
mkIsGObject,
) where
import System.Glib.FFI
import System.Glib.GType
import System.Glib.GObject
-- The usage of foreignPtrToPtr should be safe as the evaluation will only be
-- forced if the object is used afterwards
--
mkCastToGObject :: (GObjectClass obj, GObjectClass obj')
=> GType
-> String
-> (obj -> obj')
mkCastToGObject gtype objTypeName obj =
case toGObject obj of
gobj@(GObject objFPtr)
| typeInstanceIsA ((unsafeForeignPtrToPtr.castForeignPtr) objFPtr) gtype
-> unsafeCastGObject gobj
| otherwise -> error $ "Cannot cast object to " ++ objTypeName
mkIsGObject :: GObjectClass obj
=> GType
-> obj
-> Bool
mkIsGObject gType obj =
unsafePerformIO $
withForeignPtr (unGObject $ toGObject obj) $ \objPtr ->
return $ typeInstanceIsA (castPtr objPtr) gType
|
