Enum ProgressToken 

pub enum ProgressToken {
    Number(i64),
    Text(Arc<str>),
}

The opaque handle a request carries to ask for progress updates.

Why this is the second non-Copy newtype

crate::domain::RequestId is not Copy because it wraps an Arc<str>, and this does too, for the same reason: a progress token is stored on the in-flight entry when the request arrives and read again for every update until it completes, so a notification re-uses the request’s allocation instead of making one. RequestId’s doc comment says it is the only such newtype; this is the one exception, and it is the same reason rather than a new one — a token duplicated by value is a correlation the peer did not ask for.

Variants

Number(i64)

A numeric token.

Text(Arc<str>)

A string token.

Implementations

impl ProgressToken

pub const fn number(value: i64) -> Self

A numeric token.

pub fn text(value: impl AsRef<str>) -> Self

A string token.

pub fn from_json(value: &Value) -> Option<Self>

Reads a token out of the JSON a request carried.

The one place the wire shape is known, and it is the shape the vendored schema states: a string or a number, nothing else. A boolean, an object or a fractional number is not a ProgressToken, and returning None for one is what lets the request proceed with no progress rather than failing — the token is a request for updates, not a requirement for the request to be valid.

pub fn to_json(&self) -> Cow<'_, str>

The token as JSON, for a codec to write back.

A string is quoted, so the result pastes into a document without the caller needing to know which arm it got. Borrowed rather than owned: the codec serialises it into a buffer it already holds.

Trait Implementations

impl Clone for ProgressToken

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ProgressToken

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

Formats the value using the given formatter.

impl Display for ProgressToken

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

Formats the value using the given formatter.

impl Eq for ProgressToken

impl Hash for ProgressToken

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for ProgressToken

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for ProgressToken