{-# LANGUAGE TypeApplications #-}


-- | Copyright  : Will Thompson, Iñaki García Etxebarria and Jonas Platte
-- License    : LGPL-2.1
-- Maintainer : Iñaki García Etxebarria
-- 
-- A structure containing a weak reference to a t'GI.GObject.Objects.Object.Object'.  It can either
-- be empty (i.e. point to 'P.Nothing'), or point to an object for as long as
-- at least one \"strong\" reference to that object exists. Before the
-- object\'s t'GI.GObject.Structs.ObjectClass.ObjectClass'.@/dispose/@ method is called, every t'GI.GObject.Structs.WeakRef.WeakRef'
-- associated with becomes empty (i.e. points to 'P.Nothing').
-- 
-- Like t'GI.GObject.Structs.Value.Value', t'GI.GObject.Structs.WeakRef.WeakRef' can be statically allocated, stack- or
-- heap-allocated, or embedded in larger structures.
-- 
-- Unlike @/g_object_weak_ref()/@ and @/g_object_add_weak_pointer()/@, this weak
-- reference is thread-safe: converting a weak pointer to a reference is
-- atomic with respect to invalidation of weak pointers to destroyed
-- objects.
-- 
-- If the object\'s t'GI.GObject.Structs.ObjectClass.ObjectClass'.@/dispose/@ method results in additional
-- references to the object being held, any @/GWeakRefs/@ taken
-- before it was disposed will continue to point to 'P.Nothing'.  If
-- @/GWeakRefs/@ are taken after the object is disposed and
-- re-referenced, they will continue to point to it until its refcount
-- goes back to zero, at which point they too will be invalidated.

#if (MIN_VERSION_haskell_gi_overloading(1,0,0) && !defined(__HADDOCK_VERSION__))
#define ENABLE_OVERLOADING
#endif

module GI.GObject.Structs.WeakRef
    ( 

-- * Exported types
    WeakRef(..)                             ,
    noWeakRef                               ,


 -- * Methods
-- ** Overloaded methods #method:Overloaded methods#

#if defined(ENABLE_OVERLOADING)
    ResolveWeakRefMethod                    ,
#endif




    ) where

import Data.GI.Base.ShortPrelude
import qualified Data.GI.Base.ShortPrelude as SP
import qualified Data.GI.Base.Overloading as O
import qualified Prelude as P

import qualified Data.GI.Base.Attributes as GI.Attributes
import qualified Data.GI.Base.ManagedPtr as B.ManagedPtr
import qualified Data.GI.Base.GClosure as B.GClosure
import qualified Data.GI.Base.GError as B.GError
import qualified Data.GI.Base.GVariant as B.GVariant
import qualified Data.GI.Base.GValue as B.GValue
import qualified Data.GI.Base.GParamSpec as B.GParamSpec
import qualified Data.GI.Base.CallStack as B.CallStack
import qualified Data.GI.Base.Properties as B.Properties
import qualified Data.GI.Base.Signals as B.Signals
import qualified Data.Text as T
import qualified Data.ByteString.Char8 as B
import qualified Data.Map as Map
import qualified Foreign.Ptr as FP
import qualified GHC.OverloadedLabels as OL


-- | Memory-managed wrapper type.
newtype WeakRef = WeakRef (ManagedPtr WeakRef)
    deriving (WeakRef -> WeakRef -> Bool
(WeakRef -> WeakRef -> Bool)
-> (WeakRef -> WeakRef -> Bool) -> Eq WeakRef
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: WeakRef -> WeakRef -> Bool
$c/= :: WeakRef -> WeakRef -> Bool
== :: WeakRef -> WeakRef -> Bool
$c== :: WeakRef -> WeakRef -> Bool
Eq)
-- XXX Wrapping a foreign struct/union with no known destructor or size, leak?
instance WrappedPtr WeakRef where
    wrappedPtrCalloc :: IO (Ptr WeakRef)
wrappedPtrCalloc = Ptr WeakRef -> IO (Ptr WeakRef)
forall (m :: * -> *) a. Monad m => a -> m a
return Ptr WeakRef
forall a. Ptr a
nullPtr
    wrappedPtrCopy :: WeakRef -> IO WeakRef
wrappedPtrCopy = WeakRef -> IO WeakRef
forall (m :: * -> *) a. Monad m => a -> m a
return
    wrappedPtrFree :: Maybe (GDestroyNotify WeakRef)
wrappedPtrFree = Maybe (GDestroyNotify WeakRef)
forall a. Maybe a
Nothing

-- | A convenience alias for `Nothing` :: `Maybe` `WeakRef`.
noWeakRef :: Maybe WeakRef
noWeakRef :: Maybe WeakRef
noWeakRef = Maybe WeakRef
forall a. Maybe a
Nothing


#if defined(ENABLE_OVERLOADING)
instance O.HasAttributeList WeakRef
type instance O.AttributeList WeakRef = WeakRefAttributeList
type WeakRefAttributeList = ('[ ] :: [(Symbol, *)])
#endif

#if defined(ENABLE_OVERLOADING)
type family ResolveWeakRefMethod (t :: Symbol) (o :: *) :: * where
    ResolveWeakRefMethod l o = O.MethodResolutionFailed l o

instance (info ~ ResolveWeakRefMethod t WeakRef, O.MethodInfo info WeakRef p) => OL.IsLabel t (WeakRef -> p) where
#if MIN_VERSION_base(4,10,0)
    fromLabel = O.overloadedMethod @info
#else
    fromLabel _ = O.overloadedMethod @info
#endif

#endif