tinymist_analysis/adt/
snapshot_map.rs

1//! Upstream [rustc_data_structures::snapshot_map].
2//! Last checked commit: f4bb4500ddb4
3//! Last checked time:   2023-12-28
4//!
5//! [rustc_data_structures::snapshot_map]: https://github.com/rust-lang/rust/blob/master/compiler/rustc_data_structures/src/snapshot_map/mod.rs
6
7#![allow(unused)]
8
9use ena::undo_log::{Rollback, Snapshots, UndoLogs, VecLog};
10use std::borrow::{Borrow, BorrowMut};
11use std::hash::Hash;
12use std::marker::PhantomData;
13use std::ops;
14
15pub use ena::undo_log::Snapshot;
16
17type FxHashMap<K, V> = rustc_hash::FxHashMap<K, V>;
18
19pub type SnapshotMapStorage<K, V> = SnapshotMap<K, V, FxHashMap<K, V>, ()>;
20pub type SnapshotMapRef<'a, K, V, L> = SnapshotMap<K, V, &'a mut FxHashMap<K, V>, &'a mut L>;
21
22#[derive(Clone)]
23pub struct SnapshotMap<K, V, M = FxHashMap<K, V>, L = VecLog<UndoLog<K, V>>> {
24    map: M,
25    undo_log: L,
26    _marker: PhantomData<(K, V)>,
27}
28
29// HACK(eddyb) manual impl avoids `Default` bounds on `K` and `V`.
30impl<K, V, M, L> Default for SnapshotMap<K, V, M, L>
31where
32    M: Default,
33    L: Default,
34{
35    fn default() -> Self {
36        SnapshotMap {
37            map: Default::default(),
38            undo_log: Default::default(),
39            _marker: PhantomData,
40        }
41    }
42}
43
44#[derive(Clone)]
45pub enum UndoLog<K, V> {
46    Inserted(K),
47    Overwrite(K, V),
48    Purged,
49}
50
51impl<K, V, M, L> SnapshotMap<K, V, M, L> {
52    #[inline]
53    pub fn with_log<L2>(&mut self, undo_log: L2) -> SnapshotMap<K, V, &mut M, L2> {
54        SnapshotMap {
55            map: &mut self.map,
56            undo_log,
57            _marker: PhantomData,
58        }
59    }
60}
61
62impl<K, V, M, L> SnapshotMap<K, V, M, L>
63where
64    K: Hash + Clone + Eq,
65    M: BorrowMut<FxHashMap<K, V>> + Borrow<FxHashMap<K, V>>,
66    L: UndoLogs<UndoLog<K, V>>,
67{
68    pub fn clear(&mut self) {
69        self.map.borrow_mut().clear();
70        self.undo_log.clear();
71    }
72
73    pub fn entries(&self) -> impl Iterator<Item = (&K, &V)> {
74        self.map.borrow().iter()
75    }
76
77    pub fn values(&self) -> impl Iterator<Item = &V> {
78        self.map.borrow().values()
79    }
80
81    pub fn insert(&mut self, key: K, value: V) -> bool {
82        match self.map.borrow_mut().insert(key.clone(), value) {
83            None => {
84                self.undo_log.push(UndoLog::Inserted(key));
85                true
86            }
87            Some(old_value) => {
88                self.undo_log.push(UndoLog::Overwrite(key, old_value));
89                false
90            }
91        }
92    }
93
94    pub fn remove(&mut self, key: K) -> bool {
95        match self.map.borrow_mut().remove(&key) {
96            Some(old_value) => {
97                self.undo_log.push(UndoLog::Overwrite(key, old_value));
98                true
99            }
100            None => false,
101        }
102    }
103
104    pub fn get<Q>(&self, k: &Q) -> Option<&V>
105    where
106        K: Borrow<Q>,
107        Q: Hash + Eq + ?Sized,
108    {
109        self.map.borrow().get(k)
110    }
111}
112
113impl<K, V> SnapshotMap<K, V>
114where
115    K: Hash + Clone + Eq,
116{
117    pub fn snapshot(&mut self) -> Snapshot {
118        self.undo_log.start_snapshot()
119    }
120
121    pub fn commit(&mut self, snapshot: Snapshot) {
122        self.undo_log.commit(snapshot)
123    }
124
125    pub fn rollback_to(&mut self, snapshot: Snapshot) {
126        let map = &mut self.map;
127        self.undo_log.rollback_to(|| map, snapshot)
128    }
129}
130
131impl<'k, K, V, M, L> ops::Index<&'k K> for SnapshotMap<K, V, M, L>
132where
133    K: Hash + Clone + Eq,
134    M: Borrow<FxHashMap<K, V>>,
135{
136    type Output = V;
137    fn index(&self, key: &'k K) -> &V {
138        &self.map.borrow()[key]
139    }
140}
141
142impl<K, V, M, L> Rollback<UndoLog<K, V>> for SnapshotMap<K, V, M, L>
143where
144    K: Eq + Hash,
145    M: Rollback<UndoLog<K, V>>,
146{
147    fn reverse(&mut self, undo: UndoLog<K, V>) {
148        self.map.reverse(undo)
149    }
150}
151
152impl<K, V> Rollback<UndoLog<K, V>> for FxHashMap<K, V>
153where
154    K: Eq + Hash,
155{
156    fn reverse(&mut self, undo: UndoLog<K, V>) {
157        match undo {
158            UndoLog::Inserted(key) => {
159                self.remove(&key);
160            }
161
162            UndoLog::Overwrite(key, old_value) => {
163                self.insert(key, old_value);
164            }
165
166            UndoLog::Purged => {}
167        }
168    }
169}
tinymist_analysis/adt/snapshot_map.rs

tinymist_analysis/adt/
snapshot_map.rs
