garage/src/table/schema.rs
2020-07-08 17:34:37 +02:00

76 lines
1.6 KiB
Rust

use async_trait::async_trait;
use serde::{Deserialize, Serialize};
use garage_util::data::*;
use garage_util::error::Error;
pub trait PartitionKey {
fn hash(&self) -> Hash;
}
pub trait SortKey {
fn sort_key(&self) -> &[u8];
}
pub trait Entry<P: PartitionKey, S: SortKey>:
PartialEq + Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync
{
fn partition_key(&self) -> &P;
fn sort_key(&self) -> &S;
fn merge(&mut self, other: &Self);
}
#[derive(Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct EmptyKey;
impl SortKey for EmptyKey {
fn sort_key(&self) -> &[u8] {
&[]
}
}
impl PartitionKey for EmptyKey {
fn hash(&self) -> Hash {
[0u8; 32].into()
}
}
impl PartitionKey for String {
fn hash(&self) -> Hash {
hash(self.as_bytes())
}
}
impl SortKey for String {
fn sort_key(&self) -> &[u8] {
self.as_bytes()
}
}
impl PartitionKey for Hash {
fn hash(&self) -> Hash {
self.clone()
}
}
impl SortKey for Hash {
fn sort_key(&self) -> &[u8] {
self.as_slice()
}
}
#[async_trait]
pub trait TableSchema: Send + Sync {
type P: PartitionKey + Clone + PartialEq + Serialize + for<'de> Deserialize<'de> + Send + Sync;
type S: SortKey + Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync;
type E: Entry<Self::P, Self::S>;
type Filter: Clone + Serialize + for<'de> Deserialize<'de> + Send + Sync;
// Action to take if not able to decode current version:
// try loading from an older version
fn try_migrate(_bytes: &[u8]) -> Option<Self::E> {
None
}
async fn updated(&self, old: Option<Self::E>, new: Option<Self::E>) -> Result<(), Error>;
fn matches_filter(_entry: &Self::E, _filter: &Self::Filter) -> bool {
true
}
}