// Copyright © 2022 The Radicle Link Contributors
use crypto::ssh::ExtendedSignature;
use crate::{CollaborativeObject, Evaluate, ObjectId, TypeName, change_graph::ChangeGraph};
use super::error;
/// Get a [`CollaborativeObject`], if it exists.
///
/// The `storage` is the backing storage for storing
/// [`crate::Entry`]s at content-addressable locations. Please see
/// [`crate::Store`] for further information.
///
/// The `typename` is the type of object to be found, while the
/// `object_id` is the identifier for the particular object under that
/// type.
pub fn get<T, S>(
storage: &S,
typename: &TypeName,
oid: &ObjectId,
) -> Result<Option<CollaborativeObject<T>>, error::Retrieve>
where
T: Evaluate<S>,
S: crate::object::Storage,
S: crate::change::Storage<
ObjectId = crate::object::Oid,
Parent = crate::object::Oid,
Signatures = ExtendedSignature,
>,
{
let tip_refs = storage
.objects(typename, oid)
.map_err(|err| error::Retrieve::Refs { err: Box::new(err) })?;
ChangeGraph::load(storage, tip_refs.iter(), typename, oid)
.map(|graph| graph.evaluate(storage).map_err(error::Retrieve::evaluate))
.transpose()
}