tenebrous-dicebot/src/db.rs

83 lines
2.2 KiB
Rust
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use byteorder::LittleEndian;
use sled::{Db, IVec};
use thiserror::Error;
use zerocopy::byteorder::I32;
use zerocopy::{AsBytes, LayoutVerified};
#[derive(Clone)]
pub struct Database {
db: Db,
}
#[derive(Error, Debug)]
pub enum DataError {
#[error("value does not exist for key: {0}")]
KeyDoesNotExist(String),
#[error("internal database error: {0}")]
InternalError(#[from] sled::Error),
}
fn to_key(room_id: &str, username: &str, variable_name: &str) -> Vec<u8> {
let mut key = vec![];
key.extend_from_slice(room_id.as_bytes());
key.extend_from_slice(username.as_bytes());
key.extend_from_slice(variable_name.as_bytes());
key
}
impl Database {
pub fn new(db: &Db) -> Database {
Database { db: db.clone() }
}
pub fn get_user_variable(
&self,
room_id: &str,
username: &str,
variable_name: &str,
) -> Result<Option<i32>, DataError> {
let key = to_key(room_id, username, variable_name);
if let Some(raw_value) = self.db.get(key)? {
let layout: LayoutVerified<&[u8], I32<LittleEndian>> =
LayoutVerified::new_unaligned(&*raw_value).expect("bytes do not fit schema");
let value: I32<LittleEndian> = *layout;
Ok(Some(value.get()))
} else {
Ok(None)
}
}
pub fn set_user_variable(
&self,
room_id: &str,
username: &str,
variable_name: &str,
value: i32,
) -> Result<(), DataError> {
let key = to_key(room_id, username, variable_name);
let db_value: I32<LittleEndian> = I32::new(value);
self.db.insert(key, IVec::from(db_value.as_bytes()))?;
Ok(())
}
pub fn delete_user_variable(
&self,
room_id: &str,
username: &str,
variable_name: &str,
) -> Result<(), DataError> {
let key = to_key(room_id, username, variable_name);
if let Some(_) = self.db.remove(key)? {
Ok(())
} else {
let mut key = room_id.to_owned();
key.push_str(username);
key.push_str(variable_name);
Err(DataError::KeyDoesNotExist(key))
}
}
}