keri 0.8.2

Core library for the Key Event Receipt Infrastructure
Documentation 
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use crate::{
    error::Error,
    event::{event_data::EventData, sections::KeyConfig},
    event_message::EventTypeTag,
    prefix::{BasicPrefix, IdentifierPrefix, SelfAddressingPrefix},
};
use serde::{Deserialize, Serialize};
use serde_hex::{Compact, SerHex};

#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Default)]
pub struct LastEstablishmentData {
    #[serde(rename = "s", with = "SerHex::<Compact>")]
    pub(crate) sn: u64,
    #[serde(rename = "d")]
    pub(crate) digest: SelfAddressingPrefix,
    pub(crate) br: Vec<BasicPrefix>,
    pub(crate) ba: Vec<BasicPrefix>,
}

/// Identifier State
///
/// represents the accumulated state after applying events, based on section 13 of the paper
#[derive(Default, PartialEq, Debug, Clone, Serialize, Deserialize)]
pub struct IdentifierState {
    #[serde(rename = "i")]
    pub prefix: IdentifierPrefix,

    #[serde(rename = "s", with = "SerHex::<Compact>")]
    pub sn: u64,

    #[serde(rename = "d")]
    pub last_event_digest: SelfAddressingPrefix,

    #[serde(rename = "p")]
    pub last_previous: Option<SelfAddressingPrefix>,

    #[serde(rename = "et")]
    pub last_event_type: Option<EventTypeTag>,

    #[serde(flatten)]
    pub current: KeyConfig,

    #[serde(rename = "bt", with = "SerHex::<Compact>")]
    pub tally: u64,

    #[serde(rename = "b")]
    pub witnesses: Vec<BasicPrefix>,

    #[serde(rename = "di")]
    pub delegator: Option<IdentifierPrefix>,

    #[serde(rename = "ee")]
    pub last_est: LastEstablishmentData,
}

impl EventTypeTag {
    pub fn is_establishment_event(&self) -> bool {
        matches!(
            self,
            EventTypeTag::Icp | EventTypeTag::Rot | EventTypeTag::Dip | EventTypeTag::Drt
        )
    }
}

impl From<&EventData> for EventTypeTag {
    fn from(ed: &EventData) -> Self {
        match ed {
            EventData::Icp(_) => EventTypeTag::Icp,
            EventData::Rot(_) => EventTypeTag::Rot,
            EventData::Ixn(_) => EventTypeTag::Ixn,
            EventData::Dip(_) => EventTypeTag::Dip,
            EventData::Drt(_) => EventTypeTag::Drt,
        }
    }
}

impl IdentifierState {
    /// Apply
    ///
    /// validates and applies the semantic rules of the event to the event state
    pub fn apply<T: EventSemantics>(self, event: &T) -> Result<Self, Error> {
        event.apply_to(self)
    }
}

/// EventSemantics
///
/// Describes an interface for applying the semantic rule of an event to the state of an Identifier
pub trait EventSemantics {
    fn apply_to(&self, state: IdentifierState) -> Result<IdentifierState, Error> {
        // default impl is the identity transition
        Ok(state)
    }
}