WeakRefProtocol

public protocol WeakRefProtocol

The WeakRefProtocol protocol exposes the methods and properties of an underlying GWeakRef instance. The default implementation of these can be found in the protocol extension below. For a concrete class that implements these methods and properties, see WeakRef. Alternatively, use WeakRefRef as a lighweight, unowned reference if you already have an instance you just want to use.

A structure containing a weak reference to a GObject. It can either be empty (i.e. point to nil), or point to an object for as long as at least one “strong” reference to that object exists. Before the object’s GObjectClass.dispose method is called, every GWeakRef associated with becomes empty (i.e. points to nil).

Like GValue, GWeakRef 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 GObjectClass.dispose method results in additional references to the object being held, any GWeakRefs taken before it was disposed will continue to point to nil. 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.

  • ptr

    Untyped pointer to the underlying GWeakRef instance.

    Declaration

    Swift

    var ptr: UnsafeMutableRawPointer! { get }
  • _ptr Default implementation

    Typed pointer to the underlying GWeakRef instance.

    Default Implementation

    Return the stored, untyped pointer as a typed pointer to the GWeakRef instance.

    Declaration

    Swift

    var _ptr: UnsafeMutablePointer<GWeakRef>! { get }

WeakRef Record: WeakRefProtocol extension (methods and fields)

  • clear() Extension method

    Frees resources associated with a non-statically-allocated GWeakRef. After this call, the GWeakRef is left in an undefined state.

    You should only call this on a GWeakRef that previously had g_weak_ref_init() called on it.

    Declaration

    Swift

    @inlinable
    func clear()
  • get() Extension method

    If weak_ref is not empty, atomically acquire a strong reference to the object it points to, and return that reference.

    This function is needed because of the potential race between taking the pointer value and g_object_ref() on it, if the object was losing its last reference at the same time in a different thread.

    The caller should release the resulting reference in the usual way, by using g_object_unref().

    Declaration

    Swift

    @inlinable
    func get() -> ObjectRef!
  • init_(object:) Extension method

    Initialise a non-statically-allocated GWeakRef.

    This function also calls g_weak_ref_set() with object on the freshly-initialised weak reference.

    This function should always be matched with a call to g_weak_ref_clear(). It is not necessary to use this function for a GWeakRef in static storage because it will already be properly initialised. Just use g_weak_ref_set() directly.

    Declaration

    Swift

    @inlinable
    func init_(object: ObjectRef? = nil)
  • init_(object:) Extension method

    Initialise a non-statically-allocated GWeakRef.

    This function also calls g_weak_ref_set() with object on the freshly-initialised weak reference.

    This function should always be matched with a call to g_weak_ref_clear(). It is not necessary to use this function for a GWeakRef in static storage because it will already be properly initialised. Just use g_weak_ref_set() directly.

    Declaration

    Swift

    @inlinable
    func init_<ObjectT>(object: ObjectT?) where ObjectT : ObjectProtocol
  • set(object:) Extension method

    Change the object to which weak_ref points, or set it to nil.

    You must own a strong reference on object while calling this function.

    Declaration

    Swift

    @inlinable
    func set(object: ObjectRef? = nil)
  • set(object:) Extension method

    Change the object to which weak_ref points, or set it to nil.

    You must own a strong reference on object while calling this function.

    Declaration

    Swift

    @inlinable
    func set<ObjectT>(object: ObjectT?) where ObjectT : ObjectProtocol