harmos-runtime 0.1.6

Harmos runtime: managed state, undo, recovery, background work and typed streams.
Documentation 
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/* ***
 *
 * Harmos
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * ***
 */

/* === Modules === */

pub(crate) mod dispatch {
    use std::collections::BTreeMap;

    use crate::Application;
    use crate::state::envelope::{DefinitionId, Envelope, Kind};
    use crate::state::record::Upgrade;
    use crate::state::transaction::DecodeError;

    pub(crate) type Restore<A, W> = fn(W, &mut <A as Application>::State) -> Result<(), DecodeError>;
    pub(crate) type Decode<A> = fn(&DefinitionId, u32, &[u8]) -> Result<Option<<A as Application>::Transaction>, DecodeError>;

    #[derive(Debug)]
    pub(crate) enum Restored<A: Application> {
        Applied,
        Recorded(A::Record),
        Skipped,
    }

    pub(crate) struct Dispatch<A: Application, W> {
        transactions: BTreeMap<(DefinitionId, u32), Restore<A, W>>,
        decoders: BTreeMap<(DefinitionId, u32), Decode<A>>,
        records: BTreeMap<(DefinitionId, u32), Upgrade<A, W>>,
    }

    impl<A: Application, W> Dispatch<A, W> {
        pub(crate) fn set_transaction(&mut self, id: DefinitionId, version: u32, restore: Restore<A, W>, decode: Decode<A>) {
            self.transactions.insert((id.clone(), version), restore);
            self.decoders.insert((id, version), decode);
        }

        pub(crate) fn set_record(&mut self, id: DefinitionId, version: u32, upgrade: Upgrade<A, W>) {
            self.records.insert((id, version), upgrade);
        }

        pub(crate) fn restore(&self, envelope: Envelope<W>, state: &mut A::State) -> Result<Restored<A>, DecodeError> {
            let Envelope { kind, id, version, payload, .. } = envelope;

            match kind {
                Kind::Transaction => {
                    let restore = declared(&self.transactions, &id, version)?;
                    restore(payload, state)?;
                    Ok(Restored::Applied)
                }
                Kind::Record => match declared(&self.records, &id, version) {
                    Ok(upgrade) => Ok(Restored::Recorded(upgrade(payload)?)),
                    Err(DecodeError::UnknownDefinition { .. }) => Ok(Restored::Skipped),
                    Err(loud) => Err(loud),
                },
            }
        }

        pub(crate) fn has_record(&self, id: &DefinitionId, version: u32) -> Result<bool, DecodeError> {
            match declared(&self.records, id, version) {
                Ok(_) => Ok(true),
                Err(DecodeError::UnknownDefinition { .. }) => Ok(false),
                Err(error) => Err(error),
            }
        }

        pub(crate) fn decode_transaction(&self, id: &DefinitionId, version: u32, bytes: &[u8]) -> Result<A::Transaction, DecodeError> {
            let decode = declared(&self.decoders, id, version)?;

            decode(id, version, bytes)?.ok_or_else(|| DecodeError::Malformed { id: id.clone(), version })
        }
    }

    impl<A: Application, W> Default for Dispatch<A, W> {
        fn default() -> Self {
            Self { transactions: BTreeMap::new(), decoders: BTreeMap::new(), records: BTreeMap::new() }
        }
    }

    fn declared<F: Copy>(table: &BTreeMap<(DefinitionId, u32), F>, id: &DefinitionId, version: u32) -> Result<F, DecodeError> {
        if let Some(found) = table.get(&(id.clone(), version)) {
            return Ok(*found);
        }
        let known = table.range((id.clone(), u32::MIN)..=(id.clone(), u32::MAX)).next().is_some();

        Err(if known {
            DecodeError::UndeclaredVersion { id: id.clone(), version }
        } else {
            DecodeError::UnknownDefinition { id: id.clone() }
        })
    }
}

/* === Re-Exports === */

pub use harmos_domain::state::{Catalogued, DecodeError, Invert, Mutual, Never, Transaction, TransactionCatalog, Undoable};

/* === Imports === */

// Standard Library Imports

// Third Party Imports

// Local Imports
use crate::Application;

/* === Constants === */

/* === Macros === */

/* === Type Aliases === */

pub(crate) type Inverting<A> = fn(&<A as Application>::Transaction, &<A as Application>::State) -> Option<<A as Application>::Transaction>;
pub(crate) type TransactionError<A> = <<A as Application>::Transaction as Transaction<<A as Application>::State>>::Error;

/* === Structs === */

/* === Enums === */

/* === Traits === */

/* === Implementations === */

/* === Public Functions === */

/* === Private Functions === */

/* === Tests === */