Struct State 

pub struct State { /* private fields */ }

类型安全的键值存储容器。

State 用于按类型存储和检索值，是 State 和 Configs 的底层实现。 可被 Request 和 Response 用来存储从底层协议派生的额外数据。

Implementations

impl State

pub fn new() -> State

Create an empty State.

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

Insert a type into this State.

If an extension of this type already existed, it will be returned.

Example

let mut cfg = State::new();
assert!(cfg.insert(5i32).is_none());
assert!(cfg.insert(4u8).is_none());
assert_eq!(cfg.insert(9i32), Some(5i32));

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

Get a reference to a type previously inserted on this State.

Example

let mut cfg = State::new();
assert!(cfg.get::<i32>().is_none());
cfg.insert(5i32);

assert_eq!(cfg.get::<i32>(), Some(&5i32));

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

Remove a type from this State.

If aa extension of this type existed, it will be returned.

Example

let mut cfg = State::new();
cfg.insert(5i32);
assert_eq!(cfg.remove::<i32>(), Some(5i32));
assert!(cfg.get::<i32>().is_none());

pub fn clear(&mut self)

Clear the State of all inserted extensions.

Example

let mut cfg = State::new();
cfg.insert(5i32);
cfg.clear();

assert!(cfg.get::<i32>().is_none());

pub fn is_empty(&self) -> bool

Check whether the extension set is empty or not.

Example

let mut cfg = State::new();
assert!(cfg.is_empty());
cfg.insert(5i32);
assert!(!cfg.is_empty());

pub fn len(&self) -> usize

Get the numer of extensions available.

Example

let mut cfg = State::new();
assert_eq!(cfg.len(), 0);
cfg.insert(5i32);
assert_eq!(cfg.len(), 1);

pub fn extend_from(&mut self, other: &State)

将另一个 State 的内容合并进来（浅拷贝 Arc 值）

Trait Implementations

impl Clone for State

fn clone(&self) -> State

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for State

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

Formats the value using the given formatter.

impl Default for State

fn default() -> State

Returns the “default value” for a type.