Struct OpScope 

pub struct OpScope {
    pub node: ContentHash,
    pub head: Option<ContentHash>,
}

Where and when an op is admissible: the author’s own statement of which log they are submitting into and which head they observed.

This is an admission precondition, exactly like OpKind’s prev, and it lives in the payload for the same reason prev does — the payload is what the author signs. A signature over (channel, payload) is otherwise position-independent, log-independent and occurrence-independent, so a captured op replays onto any node that trusts the key, and replays again on the node it came from as soon as CAS state returns to what it expected (ABA). prev cannot close that: it asks whether the state matches, not whether the op has run.

A head hash can occur at exactly one position in exactly one chain, which is what makes it a usable freshness token without a clock: the house rule is that elapsed time is not a thing this system measures.

The admission rule is in choir-node’s policy, not in View: the view is pure state and knows nothing about nodes or log windows.

Fields

node: ContentHash

Actor id of the node whose log this op was signed for.

head: Option<ContentHash>

A log head the author had observed when they signed. None says the author read an empty log — admissible only while the node has evicted nothing, which is the span its duplicate index still covers in full.

Trait Implementations

impl Clone for OpScope

fn clone(&self) -> OpScope

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for OpScope

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for OpScope

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for OpScope

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for OpScope

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for OpScope

impl StructuralPartialEq for OpScope