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/*
This file is part of jellything (https://codeberg.org/metamuffin/jellything)
which is licensed under the GNU Affero General Public License (version 3); see /COPYING.
Copyright (C) 2025 metamuffin <metamuffin.org>
*/
use crate::{backends::KV, indices::Index, table::Table};
use anyhow::Result;
pub struct OrderIndex<T> {
id: u32,
value: fn(&T) -> [u8; 8],
}
impl<T: 'static> OrderIndex<T> {
pub fn new(table: &mut Table<T>, id: u32, value: fn(&T) -> [u8; 8]) -> Self {
table.indices.push(Box::new(Self { id, value }));
Self { id, value }
}
fn key(&self, id: u64, val: &T) -> Vec<u8> {
let mut key = Vec::new();
key.extend(self.id.to_be_bytes());
key.extend((self.value)(val));
key.extend(id.to_be_bytes());
key
}
}
impl<T: 'static> Index<T> for OrderIndex<T> {
fn add(&self, db: &dyn KV, id: u64, val: &T) -> Result<()> {
db.set(&self.key(id, val), &[])?;
Ok(())
}
fn remove(&self, db: &dyn KV, id: u64, val: &T) -> Result<()> {
db.del(&self.key(id, val))?;
Ok(())
}
fn compare(&self, before: &T, after: &T) -> bool {
(self.value)(before) == (self.value)(after)
}
}
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