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use std::{marker::PhantomData, ops::Range};
use async_trait::async_trait;
use serde::Serialize;
use crate::{
document::{Document, Header},
schema::{self, map},
transaction::{self, OperationResult, Transaction},
Error,
};
/// Defines all interactions with a [`schema::Database`], regardless of whether it is local or remote.
#[async_trait]
pub trait Connection<'a>: Send + Sync {
/// Accesses a collection for the connected [`schema::Database`].
fn collection<C: schema::Collection + 'static>(
&'a self,
) -> Result<Collection<'a, Self, C>, Error>
where
Self: Sized;
/// Inserts a newly created document into the connected [`schema::Database`] for the [`Collection`] `C`.
async fn insert<C: schema::Collection>(&self, contents: Vec<u8>) -> Result<Header, Error>;
/// Updates an existing document in the connected [`schema::Database`] for the
/// [`Collection`] `C`. Upon success, `doc.revision` will be updated with
/// the new revision.
async fn update(&self, doc: &mut Document<'_>) -> Result<(), Error>;
/// Retrieves a stored document from [`Collection`] `C` identified by `id`.
async fn get<C: schema::Collection>(&self, id: u64)
-> Result<Option<Document<'static>>, Error>;
/// Initializes [`ViewQuery`] for [`schema::View`] `V`.
#[must_use]
fn view<V: schema::View>(&'a self) -> View<'a, Self, V>
where
Self: Sized,
{
View::new(self)
}
/// Initializes [`ViewQuery`] for [`schema::View`] `V`.
#[must_use]
async fn query<'k, V: schema::View>(
&self,
query: View<'a, Self, V>,
) -> Result<Vec<map::Serialized>, Error>
where
Self: Sized;
/// Applies a [`Transaction`] to the [`schema::Database`]. If any operation in the
/// [`Transaction`] fails, none of the operations will be applied to the
/// [`schema::Database`].
async fn apply_transaction(
&self,
transaction: Transaction<'static>,
) -> Result<Vec<OperationResult>, Error>;
/// Lists executed [`Transaction`]s from this [`schema::Database`]. By default, a maximum of
/// 1000 entries will be returned, but that limit can be overridden by
/// setting `result_limit`. A hard limit of 100,000 results will be
/// returned. To begin listing after another known `transaction_id`, pass
/// `transaction_id + 1` into `starting_id`.
async fn list_executed_transactions(
&self,
starting_id: Option<u64>,
result_limit: Option<usize>,
) -> Result<Vec<transaction::Executed<'static>>, Error>;
}
/// Interacts with a collection over a `Connection`.
pub struct Collection<'a, Cn, Cl> {
connection: &'a Cn,
_phantom: PhantomData<Cl>, // allows for extension traits to be written for collections of specific types
}
impl<'a, Cn, Cl> Collection<'a, Cn, Cl>
where
Cn: Connection<'a>,
Cl: schema::Collection,
{
/// Creates a new instance using `connection`.
pub fn new(connection: &'a Cn) -> Self {
Self {
connection,
_phantom: PhantomData::default(),
}
}
/// Adds a new `Document<Cl>` with the contents `item`.
pub async fn push<S: Serialize + Sync>(&self, item: &S) -> Result<Header, crate::Error> {
let contents = serde_cbor::to_vec(item)?;
Ok(self.connection.insert::<Cl>(contents).await?)
}
/// Retrieves a `Document<Cl>` with `id` from the connection.
pub async fn get(&self, id: u64) -> Result<Option<Document<'static>>, Error> {
self.connection.get::<Cl>(id).await
}
}
/// Parameters to query a `schema::View`.
pub struct View<'a, Cn, V: schema::View> {
connection: &'a Cn,
/// Key filtering criteria.
pub key: Option<QueryKey<V::MapKey>>,
}
impl<'a, Cn, V> View<'a, Cn, V>
where
V: schema::View,
Cn: Connection<'a>,
{
fn new(connection: &'a Cn) -> Self {
Self {
connection,
key: None,
}
}
/// Filters for entries in the view with `key`.
#[must_use]
pub fn with_key(mut self, key: V::MapKey) -> Self {
self.key = Some(QueryKey::Matches(key));
self
}
/// Filters for entries in the view with `keys`.
#[must_use]
pub fn with_keys(mut self, keys: Vec<V::MapKey>) -> Self {
self.key = Some(QueryKey::Multiple(keys));
self
}
/// Filters for entries in the view with `keys`.
#[must_use]
pub fn with_key_range(mut self, range: Range<V::MapKey>) -> Self {
self.key = Some(QueryKey::Range(range));
self
}
/// Executes the query and retrieves the results.
pub async fn query(self) -> Result<Vec<map::Serialized>, Error> {
self.connection.query(self).await
}
}
/// Filters a [`View`] by key.
pub enum QueryKey<K> {
/// Matches all entries with the key provided.
Matches(K),
/// Matches all entires with keys in the range provided.
Range(Range<K>),
/// Matches all entries that have keys that are included in the set provided.
Multiple(Vec<K>),
}