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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) 2026 metamuffin <metamuffin.org>
*/
use crate::{
backends::WriteTransaction,
indices::Index,
table::{RowNum, Table, TableNum},
};
use anyhow::Result;
use bytemuck::{NoUninit, bytes_of};
pub struct OrderIndex<T> {
id: TableNum,
value: fn(&T) -> [u8; 8],
}
#[repr(C)]
#[derive(NoUninit, Clone, Copy)]
struct Key(TableNum, [u8; 8], RowNum);
impl<T: 'static> OrderIndex<T> {
pub fn new(table: &mut Table<T>, id: TableNum, value: fn(&T) -> [u8; 8]) -> Self {
table.indices.push(Box::new(Self { id, value }));
Self { id, value }
}
}
impl<T: 'static> Index<T> for OrderIndex<T> {
fn add(&self, db: &mut dyn WriteTransaction, id: RowNum, val: &T) -> Result<()> {
db.set(bytes_of(&Key(self.id, (self.value)(val), id)), &[])
}
fn remove(&self, db: &mut dyn WriteTransaction, id: RowNum, val: &T) -> Result<()> {
db.del(bytes_of(&Key(self.id, (self.value)(val), id)))
}
fn compare(&self, before: &T, after: &T) -> bool {
(self.value)(before) == (self.value)(after)
}
}
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