Enum Ref 

pub enum Ref<V>
where
    V: ?Sized,
{
    None,
    Owned(Arc<V>),
    Borrowed(Weak<V>),
}

Holds a reference that is either None, Owned, or Borrowed.

It’s used to give a single field that can accept Option (without additional wrapping), an owned value, or a reference to an owned value (to prevent unnecessary clones).

Example

pub struct Button {
    // Allows the Button to provide its own default, accept an owned value from a parent
    // widget, or a reference to a layout.
    pub layout: Ref<Layout>,
}

Variants

None

No value.

Owned(Arc<V>)

Owned data.

Borrowed(Weak<V>)

Borrowed data. Unlike Owned, this is not guaranteed to exist, as it only holds a weak reference to the Owned value. It should never be expected for the value to exist.

Implementations

impl<V> Ref<V>

pub fn new(value: V) -> Ref<V>

Creates an Owned reference to value.

pub fn is_valid(&self) -> bool

Returns true if this reference points to a value in memory.

Will always be true if the Ref is Owned, will always be None if the Ref is None, but if it’s Borrowed, it will only return true if the borrowed value is still in memory.

pub fn try_get(&self) -> Option<Arc<V>>

Attempst to fetch the value that this reference is wrapping.

pub fn get(&self) -> Arc<V>

Fetch the underlying value that this reference is wrapping.

Panics

Will panic if the value no longer exists, or the reference is empty.

Trait Implementations

impl<V> Clone for Ref<V>

fn clone(&self) -> Ref<V>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<V> Debug for Ref<V>

where V: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<V> Default for Ref<V>

fn default() -> Ref<V>

Returns the “default value” for a type.

impl<T> From<T> for Ref<T>

fn from(val: T) -> Ref<T>

Converts to this type from the input type.