Struct script::dom::bindings::root::MutNullableDom

pub struct MutNullableDom<T: DomObject> {
    ptr: UnsafeCell<Option<Dom<T>>>,
}

A holder that provides interior mutability for GC-managed values such as Dom<T>, with nullability represented by an enclosing Option wrapper. Essentially a Cell<Option<Dom<T>>>, but safer.

This should only be used as a field in other DOM objects; see warning on Dom<T>.

Fields

ptr: UnsafeCell<Option<Dom<T>>>

Implementations

impl<T: DomObject> MutNullableDom<T>

pub fn new(initial: Option<&T>) -> MutNullableDom<T>

Create a new MutNullableDom.

pub fn or_init<F>(&self, cb: F) -> Root<Dom<T>>where
    F: FnOnce() -> Root<Dom<T>>,

Retrieve a copy of the current inner value. If it is None, it is initialized with the result of cb first.

pub unsafe fn get_inner_as_layout(&self) -> Option<LayoutDom<'_, T>>

Retrieve a copy of the inner optional Dom<T> as LayoutDom<T>. For use by layout, which can’t use safe types like Temporary.

pub fn get(&self) -> Option<Root<Dom<T>>>

Get a rooted value out of this object

pub fn set(&self, val: Option<&T>)

Set this MutNullableDom to the given value.

pub fn take(&self) -> Option<Root<Dom<T>>>

Gets the current value out of this object and sets it to None.

Trait Implementations

impl<T: DomObject> Default for MutNullableDom<T>

fn default() -> MutNullableDom<T>

Returns the “default value” for a type.

impl<T: DomObject> MallocSizeOf for MutNullableDom<T>

fn size_of(&self, _ops: &mut MallocSizeOfOps) -> usize

Measure the heap usage of all descendant heap-allocated structures, but not the space taken up by the value itself.

impl<T: DomObject> PartialEq<MutNullableDom<T>> for MutNullableDom<T>

fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a, T: DomObject> PartialEq<Option<&'a T>> for MutNullableDom<T>

fn eq(&self, other: &Option<&T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T> Traceable for MutNullableDom<T>where
    T: JSTraceable + DomObject,

unsafe fn trace(&self, tracer: *mut JSTracer)

Trace self.