coven_protocol/membership/
head_predecessor.rs

1use super::{AuthorHead, MembershipHeadActivation, MembershipHeadRef};
2use crate::objects::ExactObjectRef;
3use crate::store_commit::StoreProtocolError;
4use serde::{Deserialize, Serialize};
5
6/// The exact predecessor head and, for a Store control, its finalized result.
7#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
8#[serde(tag = "kind", rename_all = "snake_case", deny_unknown_fields)]
9pub enum MembershipHeadPredecessor {
10    Direct {
11        head: MembershipHeadRef,
12    },
13    Accepted {
14        head: MembershipHeadRef,
15        acceptance: ExactObjectRef,
16    },
17}
18
19impl MembershipHeadPredecessor {
20    pub fn head(&self) -> &MembershipHeadRef {
21        match self {
22            Self::Direct { head } | Self::Accepted { head, .. } => head,
23        }
24    }
25
26    pub fn acceptance(&self) -> Option<&ExactObjectRef> {
27        match self {
28            Self::Direct { .. } => None,
29            Self::Accepted { acceptance, .. } => Some(acceptance),
30        }
31    }
32
33    pub fn verify_head(&self, head: &AuthorHead) -> Result<(), StoreProtocolError> {
34        self.head().object.verify(&head.to_bytes())?;
35        if self.head().coord != head.entry_coord() || self.head().head_hash != head.head_hash() {
36            return Err(StoreProtocolError::Malformed(
37                "membership predecessor differs from its exact head".into(),
38            ));
39        }
40        match (self, &head.activation) {
41            (Self::Direct { .. }, MembershipHeadActivation::Direct) => Ok(()),
42            (
43                Self::Accepted { acceptance, .. },
44                MembershipHeadActivation::StoreCommit {
45                    acceptance_slot, ..
46                },
47            ) if acceptance.slot() == acceptance_slot => Ok(()),
48            _ => Err(StoreProtocolError::Malformed(
49                "membership predecessor omits or changes its exact acceptance result".into(),
50            )),
51        }
52    }
53}
coven_protocol/membership/head_predecessor.rs

coven_protocol/membership/
head_predecessor.rs
