Data.GI.Base.BasicTypes

Basic types used in the bindings.

GType related

module Data.GI.Base.GType

Memory management

data ManagedPtr a

Thin wrapper over ForeignPtr, supporting the extra notion of disowning, that is, not running the finalizers associated with the foreign ptr.

Constructors

ManagedPtr

Fields

• managedForeignPtr :: ForeignPtr a
• managedPtrIsOwned :: IORef Bool

type ManagedPtrNewtype a = Coercible a (ManagedPtr ())

A constraint ensuring that the given type is coercible to a ManagedPtr. It will hold for newtypes of the form

newtype Foo = Foo (ManagedPtr Foo)

which is the typical shape of wrapped GObjects.

class ManagedPtrNewtype a => BoxedObject a where

Wrapped boxed structures, identified by their GType.

Minimal complete definition

boxedType

Methods

boxedType :: a -> IO GType

Instances

BoxedObject Closure

Methods

boxedType :: Closure -> IO GType

BoxedObject GError

Methods

boxedType :: GError -> IO GType

BoxedObject GValue

Methods

boxedType :: GValue -> IO GType

class BoxedEnum a where

Enums with an associated GType.

Minimal complete definition

boxedEnumType

Methods

boxedEnumType :: a -> IO GType

class BoxedFlags a where

Flags with an associated GType.

Minimal complete definition

boxedFlagsType

Methods

boxedFlagsType :: Proxy a -> IO GType

class ManagedPtrNewtype a => GObject a where

A wrapped GObject.

Minimal complete definition

gobjectIsInitiallyUnowned, gobjectType

Methods

gobjectIsInitiallyUnowned :: a -> Bool

Whether the GObject is a descendent of GInitiallyUnowned.

gobjectType :: a -> IO GType

The GType for this object.

Instances

(TypeError Constraint ((:<>:) ((:<>:) (Text "Type \8216") (ShowType * a)) (Text "\8217 does not descend from GObject.")), ManagedPtrNewtype a) => GObject a

Methods

gobjectIsInitiallyUnowned :: a -> Bool

gobjectType :: a -> IO GType

class ManagedPtrNewtype a => WrappedPtr a where

Pointers to structs/unions without an associated GType.

Minimal complete definition

wrappedPtrCalloc, wrappedPtrCopy, wrappedPtrFree

Methods

wrappedPtrCalloc :: IO (Ptr a)

Allocate a zero-initialized block of memory for the given type.

wrappedPtrCopy :: Ptr a -> IO (Ptr a)

Make a copy of the given pointer.

wrappedPtrFree :: Maybe (FunPtr (Ptr a -> IO ()))

A pointer to a function for freeing the given pointer, or Nothing is the memory associated to the pointer does not need to be freed.

data UnexpectedNullPointerReturn

A common omission in the introspection data is missing (nullable) annotations for return types, when they clearly are nullable. (A common idiom is "Returns: valid value, or %NULL if something went wrong.")

Haskell wrappers will raise this exception if the return value is an unexpected nullPtr.

Constructors

UnexpectedNullPointerReturn

Fields

• nullPtrErrorMsg :: Text

Instances

Show UnexpectedNullPointerReturn

Methods

showsPrec :: Int -> UnexpectedNullPointerReturn -> ShowS

show :: UnexpectedNullPointerReturn -> String

showList :: [UnexpectedNullPointerReturn] -> ShowS

Exception UnexpectedNullPointerReturn

Methods

toException :: UnexpectedNullPointerReturn -> SomeException

fromException :: SomeException -> Maybe UnexpectedNullPointerReturn

displayException :: UnexpectedNullPointerReturn -> String

class NullToNothing a where

Minimal complete definition

nullToNothing

Methods

nullToNothing :: MonadIO m => IO a -> m (Maybe (UnMaybe a))

Some functions are not marked as having a nullable return type in the introspection data. The result is that they currently do not return a Maybe type. This functions lets you work around this in a way that will not break when the introspection data is fixed.

When you want to call a someHaskellGIFunction that may return null wrap the call like this.

nullToNothing (someHaskellGIFunction x y)

The result will be a Maybe type even if the introspection data has not been fixed for someHaskellGIFunction yet.

Instances

(~) * a (UnMaybe a) => NullToNothing a

Methods

nullToNothing :: MonadIO m => IO a -> m (Maybe (UnMaybe a))

NullToNothing (Maybe a)

Methods

nullToNothing :: MonadIO m => IO (Maybe a) -> m (Maybe (UnMaybe (Maybe a)))

Basic GLib / GObject types

newtype GVariant

A GVariant. See Data.GI.Base.GVariant for further methods.

Constructors

GVariant (ManagedPtr GVariant)

Instances

IsGVariant GVariant

Methods

toGVariant :: GVariant -> IO GVariant

fromGVariant :: GVariant -> IO (Maybe GVariant)

toGVariantFormatString :: GVariant -> Text

newtype GParamSpec

A GParamSpec. See Data.GI.Base.GParamSpec for further methods.

Constructors

GParamSpec (ManagedPtr GParamSpec)

data GArray a

A GArray. Marshalling for this type is done in Data.GI.Base.BasicConversions, it is mapped to a list on the Haskell side.

Constructors

GArray (Ptr (GArray a))

data GPtrArray a

A GPtrArray. Marshalling for this type is done in Data.GI.Base.BasicConversions, it is mapped to a list on the Haskell side.

Constructors

GPtrArray (Ptr (GPtrArray a))

data GByteArray

A GByteArray. Marshalling for this type is done in Data.GI.Base.BasicConversions, it is packed to a ByteString on the Haskell side.

Constructors

GByteArray (Ptr GByteArray)

data GHashTable a b

A GHashTable. It is mapped to a Map on the Haskell side.

Constructors

GHashTable (Ptr (GHashTable a b))

data GList a

A GList, mapped to a list on the Haskell side. Marshalling is done in Data.GI.Base.BasicConversions.

Constructors

GList (Ptr (GList a))

g_list_free :: Ptr (GList a) -> IO ()

Free the given GList.

data GSList a

A GSList, mapped to a list on the Haskell side. Marshalling is done in Data.GI.Base.BasicConversions.

Constructors

GSList (Ptr (GSList a))

g_slist_free :: Ptr (GSList a) -> IO ()

Free the given GSList.

class Enum a => IsGFlag a

An enum usable as a flag for a function.

newtype PtrWrapped a

Some APIs, such as GHashTable, pass around scalar types wrapped into a pointer. We encode such a type as follows.

Constructors

PtrWrapped

Fields

• unwrapPtr :: Ptr a

type GDestroyNotify a = FunPtr (Ptr a -> IO ())

Destroy the memory associated with a given pointer.