willow-data-model 0.4.1

#[cfg(feature = "dev")]
use arbitrary::Arbitrary;

use crate::{groupings::Coordinatelike, prelude::*};

/// The metadata associated with each Willow [Payload](https://willowprotocol.org/specs/data-model/index.html#Payload) string.
///
/// [Entries](https://willowprotocol.org/specs/data-model/index.html#Entry) are the central concept in Willow. In order to make any bytestring of data accessible to Willow, you need to create an Entry describing its metadata. Specifically, an Entry consists of
///
/// - a [namespace_id](https://willowprotocol.org/specs/data-model/index.html#entry_namespace_id) (roughly, this addresses a universe of Willow data, fully independent from all data (i.e., Entries) of different namespace ids) of type `N`,
/// - a [subspace_id](https://willowprotocol.org/specs/data-model/index.html#entry_subspace_id) (roughly, a fully indendent part of a namespace, typically subspaces correspond to individual users) of type `S`,
/// - a [path](https://willowprotocol.org/specs/data-model/index.html#entry_path) (roughly, a file-system-like way of arranging payloads hierarchically within a subspace) of type [`Path`],
/// - a [timestamp](https://willowprotocol.org/specs/data-model/index.html#entry_timestamp) (newer Entries can overwrite certain older Entries),
/// - a [payload_length](https://willowprotocol.org/specs/data-model/index.html#entry_payload_length) (the length of the payload string), and
/// - a [payload_digest](https://willowprotocol.org/specs/data-model/index.html#entry_payload_digest) (a secure hash of the payload string being inserted into Willow).
///
/// To access these six fields, use the methods of the [`Entrylike`] trait (which [`Entry`] implements). The [`EntrylikeExt`] trait provides additional helper methods, for example, methods to check which Entries can delete which other Entries.
///
/// To create Entries, use the [`Entry::builder`] or [`Entry::prefilled_builder`] functions.
///
/// # Example
///
/// ```
/// use willow_data_model::prelude::*;
///
/// let entry = Entry::builder()
///     .namespace_id("family")
///     .subspace_id("alfie")
///     .path(Path::<4, 4, 4>::new())
///     .timestamp(12345)
///     .payload_digest("some_hash")
///     .payload_length(17)
///     .build().unwrap();
///
/// assert_eq!(*entry.wdm_subspace_id(), "alfie");
///
/// let newer = Entry::prefilled_builder(&entry).timestamp(99999).build().unwrap();
/// assert!(newer.wdm_prunes(&entry));
/// ```
///
/// [Spec definition](https://willowprotocol.org/specs/data-model/index.html#Entry).
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
#[cfg_attr(feature = "dev", derive(Arbitrary))]
pub struct Entry<const MCL: usize, const MCC: usize, const MPL: usize, N, S, PD> {
    pub(crate) namespace_id: N,
    pub(crate) subspace_id: S,
    pub(crate) path: Path<MCL, MCC, MPL>,
    pub(crate) timestamp: Timestamp,
    pub(crate) payload_length: u64,
    pub(crate) payload_digest: PD,
}

impl<const MCL: usize, const MCC: usize, const MPL: usize, N, S, PD>
    Entry<MCL, MCC, MPL, N, S, PD>
{
    /// Creates a builder for [`Entry`].
    ///
    /// # Examples
    ///
    /// ```
    /// use willow_data_model::prelude::*;
    ///
    /// // Supplying incomplete data errors.
    /// assert!(
    ///     Entry::builder()
    ///     .path(Path::<4, 4, 4>::new())
    ///     .namespace_id("family")
    ///     .subspace_id("alfie")
    ///     .payload_digest("some_hash")
    ///     // timestamp and payload_length are missing!
    ///     .build().is_err()
    /// );
    ///
    /// // Supplying all necessary data yields an entry.
    /// let entry = Entry::builder()
    ///     .namespace_id("family")
    ///     .subspace_id("alfie")
    ///     .path(Path::<4, 4, 4>::new())
    ///     .timestamp(12345)
    ///     .payload_digest("some_hash")
    ///     .payload_length(17)
    ///     .build().unwrap();
    ///
    /// assert_eq!(*entry.wdm_subspace_id(), "alfie");
    /// ```
    pub fn builder() -> EntryBuilder<MCL, MCC, MPL, N, S, PD> {
        EntryBuilder::create_empty()
    }

    /// Creates a builder which is prefilled with the data from some other entry.
    ///
    /// Use this function to create modified copies of entries.
    ///
    /// # Examples
    ///
    /// ```
    /// use willow_data_model::prelude::*;
    ///
    /// // Supplying all necessary data yields an entry.
    /// let first_entry = Entry::builder()
    ///     .namespace_id("family")
    ///     .subspace_id("alfie")
    ///     .path(Path::<4, 4, 4>::new())
    ///     .timestamp(12345)
    ///     .payload_digest("some_hash")
    ///     .payload_length(17)
    ///     .build().unwrap();
    ///
    /// assert_eq!(*first_entry.wdm_payload_digest(), "some_hash");
    ///
    /// let second_entry = Entry::prefilled_builder(&first_entry)
    ///     .timestamp(67890)
    ///     .payload_digest("another_hash")
    ///     .payload_length(4)
    ///     .build().unwrap();
    ///
    /// assert_eq!(*second_entry.wdm_payload_digest(), "another_hash");
    /// ```
    pub fn prefilled_builder<E>(source: &E) -> EntryBuilder<MCL, MCC, MPL, N, S, PD>
    where
        E: Entrylike<MCL, MCC, MPL, N, S, PD>,
        N: Clone,
        S: Clone,
        PD: Clone,
    {
        let mut builder = Self::builder();

        builder
            .namespace_id(source.wdm_namespace_id().clone())
            .subspace_id(source.wdm_subspace_id().clone())
            .path(source.wdm_path().clone())
            .timestamp(source.wdm_timestamp())
            .payload_digest(source.wdm_payload_digest().clone())
            .payload_length(source.wdm_payload_length());

        builder
    }
}

impl<const MCL: usize, const MCC: usize, const MPL: usize, N, S, PD> Keylike<MCL, MCC, MPL, S>
    for Entry<MCL, MCC, MPL, N, S, PD>
{
    fn wdm_subspace_id(&self) -> &S {
        &self.subspace_id
    }

    fn wdm_path(&self) -> &Path<MCL, MCC, MPL> {
        &self.path
    }
}

impl<const MCL: usize, const MCC: usize, const MPL: usize, N, S, PD>
    Coordinatelike<MCL, MCC, MPL, S> for Entry<MCL, MCC, MPL, N, S, PD>
{
    fn wdm_timestamp(&self) -> Timestamp {
        self.timestamp
    }
}

impl<const MCL: usize, const MCC: usize, const MPL: usize, N, S, PD>
    Entrylike<MCL, MCC, MPL, N, S, PD> for Entry<MCL, MCC, MPL, N, S, PD>
{
    fn wdm_namespace_id(&self) -> &N {
        &self.namespace_id
    }

    fn wdm_payload_length(&self) -> u64 {
        self.payload_length
    }

    fn wdm_payload_digest(&self) -> &PD {
        &self.payload_digest
    }
}