Struct GetAvailabilityParams 

#[non_exhaustive]
pub struct GetAvailabilityParams {
    pub items: Vec<AvailabilityQuery>,
    pub redirect_depth: Option<u64>,
}

Params for dig.getAvailability.

Construction

Like FetchRangeParams, this type is #[non_exhaustive]: build it with new plus the with_* setters rather than a struct literal, so a future additive field is a PATCH for every consumer instead of a semver cascade.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

items: Vec<AvailabilityQuery>

The items to check. Capped at 512 per batch (past-cap items are dropped).

redirect_depth: Option<u64>

The hop budget already consumed by this ask. Absent means zero — read it through hops_consumed, never directly.

What it means for an availability ask

An availability answer is not only this node’s holdings: on a miss it may name the holders it located, in AvailabilityAnswer::providers — the same enrichment a RedirectInfo carries. A responder that cannot answer from what it holds MAY ask its own peers, so one caller’s question can walk several hops, and each hop is a node spending someone else’s bandwidth. This field is what bounds that walk.

It is the SAME budget, counted the SAME way, as RedirectInfo::redirect_depth and as the redirect_depth that GetContentParams and FetchRangeParams already echo: the number of hops ALREADY CONSUMED when this ask arrives, counting UP from zero — never a remaining allowance counting down. A responder that asks onward sends hops_consumed() + 1 (saturating at the type maximum), and MUST NOT ask onward when that would reach the budget it advertises as RedirectInfo::max_redirects.

Absent reads as a fresh, unhopped ask, so a client written before this field existed is served unchanged.

Implementations

impl GetAvailabilityParams

pub fn new(items: Vec<AvailabilityQuery>) -> Self

An availability batch for items, asked at hop zero.

pub fn with_redirect_depth(self, redirect_depth: u64) -> Self

Echo the hop budget already consumed — from a -32008 redirect, or from the ask this one is being made on behalf of. See redirect_depth.

pub fn hops_consumed(&self) -> u64

The hops already consumed by this ask.

The single home for the “absent means zero” rule. A responder that reached for redirect_depth.is_some() instead would read every pre-0.8 client’s ask as budget-free and forward it without bound — the amplification the budget exists to stop.

Trait Implementations

impl Clone for GetAvailabilityParams

fn clone(&self) -> GetAvailabilityParams

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for GetAvailabilityParams

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for GetAvailabilityParams

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for GetAvailabilityParams

impl PartialEq for GetAvailabilityParams

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for GetAvailabilityParams

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for GetAvailabilityParams