Struct Extensions 

pub struct Extensions { /* private fields */ }

A type-map storing multiple independently-typed extension values.

Each concrete type T: Any + Send + Sync + 'static can be stored at most once. Values are wrapped in Arc for cheap cloning.

Example

use zencodec::Extensions;

let mut ext = Extensions::new();
ext.insert(42u32);
ext.insert(99.5f64);

assert_eq!(ext.get::<u32>(), Some(&42));
assert_eq!(ext.get::<f64>(), Some(&99.5));
assert_eq!(ext.get::<i32>(), None);
assert_eq!(ext.len(), 2);

Implementations

impl Extensions

pub fn new() -> Self

Create an empty extension map.

pub fn insert<T: Any + Send + Sync + 'static>(&mut self, value: T) -> Option<T>

Insert a typed value, replacing any previous value of the same type.

Returns the previous value if one existed and this is the sole Arc reference, otherwise returns None.

pub fn get<T: Any + Send + Sync + 'static>(&self) -> Option<&T>

Borrow a typed value if present.

pub fn remove<T: Any + Send + Sync + 'static>(&mut self) -> Option<T>

Remove and return a typed value.

Returns Some(T) only when this is the sole Arc reference. Returns None if the type is not present or other references exist.

pub fn contains<T: Any + Send + Sync + 'static>(&self) -> bool

Check whether a value of this type is present.

pub fn len(&self) -> usize

Number of stored extension values.

pub fn is_empty(&self) -> bool

Whether the map is empty.

Trait Implementations

impl Clone for Extensions

fn clone(&self) -> Extensions

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Extensions

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

Formats the value using the given formatter.

impl Default for Extensions

fn default() -> Extensions

Returns the “default value” for a type.