use crate::table::Table;
use crate::{DbResult, Logger, TableId};
use serde::de::DeserializeOwned;
use serde::{Deserialize, Serialize};
#[derive(Debug)]
#[cfg_attr(feature = "clone", derive(Clone))]
pub struct List<T>
where
T: Serialize + DeserializeOwned,
{
table_id: TableId,
inner: Vec<T>,
pub logger: Logger,
}
#[derive(Serialize, Deserialize)]
pub enum LogEntry<T> {
Push(T),
Insert(usize, T),
Remove(usize),
Clear,
}
impl<T> Table for List<T>
where
T: Serialize + DeserializeOwned,
{
fn init(table_id: TableId, logger: Logger) -> Self {
let inner = vec![];
Self { table_id, inner, logger }
}
fn handle_event(&mut self, bytes: &[u8]) -> DbResult<()> {
match bincode::deserialize(bytes)? {
LogEntry::Insert(idx, element) => {
self.inner.insert(idx, element);
}
LogEntry::Remove(idx) => {
self.inner.remove(idx);
}
LogEntry::Push(el) => {
self.inner.push(el);
}
LogEntry::Clear => {
self.inner.clear();
}
};
Ok(())
}
fn compact_repr(&self) -> DbResult<Vec<u8>> {
let mut repr = vec![];
for v in &self.inner {
let data = bincode::serialize(&LogEntry::Push(v))?;
let mut data = Logger::log_entry(self.table_id, data);
repr.append(&mut data);
}
Ok(repr)
}
}
impl<T> List<T>
where
T: Serialize + DeserializeOwned,
{
pub fn push(&mut self, t: T) -> DbResult<()> {
let log_entry = LogEntry::Push(&t);
let data = bincode::serialize(&log_entry)?;
self.inner.push(t);
self.logger.write(self.table_id, data)?;
Ok(())
}
pub fn pop(&mut self) -> DbResult<Option<T>> {
let log_entry: LogEntry<()> = LogEntry::Remove(self.inner.len() - 1);
let data = bincode::serialize(&log_entry)?;
let result = self.inner.pop();
self.logger.write(self.table_id, data)?;
Ok(result)
}
pub fn remove(&mut self, index: usize) -> DbResult<T> {
let log_entry: LogEntry<usize> = LogEntry::Remove(index);
let data = bincode::serialize(&log_entry)?;
let result = self.inner.remove(index);
self.logger.write(self.table_id, data)?;
Ok(result)
}
pub fn get(&self) -> &[T] {
&self.inner
}
}