1 use crate::fx::FxHashMap;
2 use crate::undo_log::{Rollback, Snapshots, UndoLogs, VecLog};
3 use std::borrow::{Borrow, BorrowMut};
5 use std::marker::PhantomData;
8 pub use crate::undo_log::Snapshot;
13 pub type SnapshotMapStorage<K, V> = SnapshotMap<K, V, FxHashMap<K, V>, ()>;
14 pub type SnapshotMapRef<'a, K, V, L> = SnapshotMap<K, V, &'a mut FxHashMap<K, V>, &'a mut L>;
17 pub struct SnapshotMap<K, V, M = FxHashMap<K, V>, L = VecLog<UndoLog<K, V>>> {
20 _marker: PhantomData<(K, V)>,
23 // HACK(eddyb) manual impl avoids `Default` bounds on `K` and `V`.
24 impl<K, V, M, L> Default for SnapshotMap<K, V, M, L>
29 fn default() -> Self {
30 SnapshotMap { map: Default::default(), undo_log: Default::default(), _marker: PhantomData }
35 pub enum UndoLog<K, V> {
41 impl<K, V, M, L> SnapshotMap<K, V, M, L> {
43 pub fn with_log<L2>(&mut self, undo_log: L2) -> SnapshotMap<K, V, &mut M, L2> {
44 SnapshotMap { map: &mut self.map, undo_log, _marker: PhantomData }
48 impl<K, V, M, L> SnapshotMap<K, V, M, L>
51 M: BorrowMut<FxHashMap<K, V>> + Borrow<FxHashMap<K, V>>,
52 L: UndoLogs<UndoLog<K, V>>,
54 pub fn clear(&mut self) {
55 self.map.borrow_mut().clear();
56 self.undo_log.clear();
59 pub fn insert(&mut self, key: K, value: V) -> bool {
60 match self.map.borrow_mut().insert(key.clone(), value) {
62 self.undo_log.push(UndoLog::Inserted(key));
66 self.undo_log.push(UndoLog::Overwrite(key, old_value));
72 pub fn remove(&mut self, key: K) -> bool {
73 match self.map.borrow_mut().remove(&key) {
75 self.undo_log.push(UndoLog::Overwrite(key, old_value));
82 pub fn get(&self, key: &K) -> Option<&V> {
83 self.map.borrow().get(key)
87 impl<K, V> SnapshotMap<K, V>
91 pub fn snapshot(&mut self) -> Snapshot {
92 self.undo_log.start_snapshot()
95 pub fn commit(&mut self, snapshot: Snapshot) {
96 self.undo_log.commit(snapshot)
99 pub fn rollback_to(&mut self, snapshot: Snapshot) {
100 let map = &mut self.map;
101 self.undo_log.rollback_to(|| map, snapshot)
105 impl<'k, K, V, M, L> ops::Index<&'k K> for SnapshotMap<K, V, M, L>
107 K: Hash + Clone + Eq,
108 M: Borrow<FxHashMap<K, V>>,
111 fn index(&self, key: &'k K) -> &V {
112 &self.map.borrow()[key]
116 impl<K, V, M, L> Rollback<UndoLog<K, V>> for SnapshotMap<K, V, M, L>
119 M: Rollback<UndoLog<K, V>>,
121 fn reverse(&mut self, undo: UndoLog<K, V>) {
122 self.map.reverse(undo)
126 impl<K, V> Rollback<UndoLog<K, V>> for FxHashMap<K, V>
130 fn reverse(&mut self, undo: UndoLog<K, V>) {
132 UndoLog::Inserted(key) => {
136 UndoLog::Overwrite(key, old_value) => {
137 self.insert(key, old_value);
140 UndoLog::Purged => {}