db_rs/
list.rs

1use crate::table::Table;
2use crate::{DbResult, Logger, TableId};
3use serde::de::DeserializeOwned;
4use serde::{Deserialize, Serialize};
5
6/// Table backed by a [Vec] of `T`
7#[derive(Debug)]
8#[cfg_attr(feature = "clone", derive(Clone))]
9pub struct List<T>
10where
11    T: Serialize + DeserializeOwned,
12{
13    table_id: TableId,
14    inner: Vec<T>,
15    pub logger: Logger,
16}
17
18#[derive(Serialize, Deserialize)]
19pub enum LogEntry<T> {
20    Push(T),
21    Insert(usize, T),
22    Remove(usize),
23    Clear,
24}
25
26impl<T> Table for List<T>
27where
28    T: Serialize + DeserializeOwned,
29{
30    fn init(table_id: TableId, logger: Logger) -> Self {
31        let inner = vec![];
32        Self { table_id, inner, logger }
33    }
34
35    fn handle_event(&mut self, bytes: &[u8]) -> DbResult<()> {
36        match bincode::deserialize(bytes)? {
37            LogEntry::Insert(idx, element) => {
38                self.inner.insert(idx, element);
39            }
40            LogEntry::Remove(idx) => {
41                self.inner.remove(idx);
42            }
43            LogEntry::Push(el) => {
44                self.inner.push(el);
45            }
46            LogEntry::Clear => {
47                self.inner.clear();
48            }
49        };
50
51        Ok(())
52    }
53
54    fn compact_repr(&self) -> DbResult<Vec<u8>> {
55        let mut repr = vec![];
56
57        for v in &self.inner {
58            let data = bincode::serialize(&LogEntry::Push(v))?;
59            let mut data = Logger::log_entry(self.table_id, data);
60            repr.append(&mut data);
61        }
62
63        Ok(repr)
64    }
65}
66
67impl<T> List<T>
68where
69    T: Serialize + DeserializeOwned,
70{
71    pub fn push(&mut self, t: T) -> DbResult<()> {
72        let log_entry = LogEntry::Push(&t);
73        let data = bincode::serialize(&log_entry)?;
74        self.inner.push(t);
75
76        self.logger.write(self.table_id, data)?;
77        Ok(())
78    }
79
80    pub fn pop(&mut self) -> DbResult<Option<T>> {
81        let log_entry: LogEntry<T> = LogEntry::Remove(self.inner.len() - 1);
82        let data = bincode::serialize(&log_entry)?;
83        let result = self.inner.pop();
84
85        self.logger.write(self.table_id, data)?;
86        Ok(result)
87    }
88
89    pub fn remove(&mut self, index: usize) -> DbResult<T> {
90        let log_entry: LogEntry<T> = LogEntry::Remove(index);
91        let data = bincode::serialize(&log_entry)?;
92        let result = self.inner.remove(index);
93
94        self.logger.write(self.table_id, data)?;
95        Ok(result)
96    }
97
98    pub fn clear(&mut self) -> DbResult<()> {
99        let log_entry: LogEntry<T> = LogEntry::Clear;
100        let data = bincode::serialize(&log_entry)?;
101        self.inner.clear();
102
103        self.logger.write(self.table_id, data)?;
104        Ok(())
105    }
106
107    pub fn get(&self) -> &[T] {
108        &self.inner
109    }
110}
db_rs/list.rs

db_rs/
list.rs
