summaryrefslogtreecommitdiffstats
path: root/src/tools/rust-analyzer/lib/la-arena/src/lib.rs
blob: f39c3a3e4ca121f80f3bf14090ea626fa6130b42 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
//! Yet another index-based arena.

#![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
#![warn(missing_docs)]

use std::{
    cmp, fmt,
    hash::{Hash, Hasher},
    iter::{Enumerate, FusedIterator},
    marker::PhantomData,
    ops::{Index, IndexMut, Range, RangeInclusive},
};

mod map;
pub use map::{ArenaMap, Entry, OccupiedEntry, VacantEntry};

/// The raw index of a value in an arena.
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct RawIdx(u32);

impl RawIdx {
    /// Constructs a [`RawIdx`] from a u32.
    pub const fn from_u32(u32: u32) -> Self {
        RawIdx(u32)
    }

    /// Deconstructs a [`RawIdx`] into the underlying u32.
    pub const fn into_u32(self) -> u32 {
        self.0
    }
}

impl From<RawIdx> for u32 {
    #[inline]
    fn from(raw: RawIdx) -> u32 {
        raw.0
    }
}

impl From<u32> for RawIdx {
    #[inline]
    fn from(idx: u32) -> RawIdx {
        RawIdx(idx)
    }
}

impl fmt::Debug for RawIdx {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.0.fmt(f)
    }
}

impl fmt::Display for RawIdx {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.0.fmt(f)
    }
}

/// The index of a value allocated in an arena that holds `T`s.
pub struct Idx<T> {
    raw: RawIdx,
    _ty: PhantomData<fn() -> T>,
}

impl<T> Ord for Idx<T> {
    fn cmp(&self, other: &Self) -> cmp::Ordering {
        self.raw.cmp(&other.raw)
    }
}

impl<T> PartialOrd for Idx<T> {
    fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
        self.raw.partial_cmp(&other.raw)
    }
}

impl<T> Clone for Idx<T> {
    fn clone(&self) -> Self {
        *self
    }
}
impl<T> Copy for Idx<T> {}

impl<T> PartialEq for Idx<T> {
    fn eq(&self, other: &Idx<T>) -> bool {
        self.raw == other.raw
    }
}
impl<T> Eq for Idx<T> {}

impl<T> Hash for Idx<T> {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.raw.hash(state);
    }
}

impl<T> fmt::Debug for Idx<T> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let mut type_name = std::any::type_name::<T>();
        if let Some(idx) = type_name.rfind(':') {
            type_name = &type_name[idx + 1..];
        }
        write!(f, "Idx::<{}>({})", type_name, self.raw)
    }
}

impl<T> Idx<T> {
    /// Creates a new index from a [`RawIdx`].
    pub const fn from_raw(raw: RawIdx) -> Self {
        Idx { raw, _ty: PhantomData }
    }

    /// Converts this index into the underlying [`RawIdx`].
    pub const fn into_raw(self) -> RawIdx {
        self.raw
    }
}

/// A range of densely allocated arena values.
pub struct IdxRange<T> {
    range: Range<u32>,
    _p: PhantomData<T>,
}

impl<T> IdxRange<T> {
    /// Creates a new index range
    /// inclusive of the start value and exclusive of the end value.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// let a = arena.alloc("a");
    /// let b = arena.alloc("b");
    /// let c = arena.alloc("c");
    /// let d = arena.alloc("d");
    ///
    /// let range = la_arena::IdxRange::new(b..d);
    /// assert_eq!(&arena[range], &["b", "c"]);
    /// ```
    pub fn new(range: Range<Idx<T>>) -> Self {
        Self { range: range.start.into_raw().into()..range.end.into_raw().into(), _p: PhantomData }
    }

    /// Creates a new index range
    /// inclusive of the start value and end value.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// let foo = arena.alloc("foo");
    /// let bar = arena.alloc("bar");
    /// let baz = arena.alloc("baz");
    ///
    /// let range = la_arena::IdxRange::new_inclusive(foo..=baz);
    /// assert_eq!(&arena[range], &["foo", "bar", "baz"]);
    ///
    /// let range = la_arena::IdxRange::new_inclusive(foo..=foo);
    /// assert_eq!(&arena[range], &["foo"]);
    /// ```
    pub fn new_inclusive(range: RangeInclusive<Idx<T>>) -> Self {
        Self {
            range: u32::from(range.start().into_raw())..u32::from(range.end().into_raw()) + 1,
            _p: PhantomData,
        }
    }

    /// Returns whether the index range is empty.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// let one = arena.alloc(1);
    /// let two = arena.alloc(2);
    ///
    /// assert!(la_arena::IdxRange::new(one..one).is_empty());
    /// ```
    pub fn is_empty(&self) -> bool {
        self.range.is_empty()
    }

    /// Returns the start of the index range.
    pub fn start(&self) -> Idx<T> {
        Idx::from_raw(RawIdx::from(self.range.start))
    }

    /// Returns the end of the index range.
    pub fn end(&self) -> Idx<T> {
        Idx::from_raw(RawIdx::from(self.range.end))
    }
}

impl<T> Iterator for IdxRange<T> {
    type Item = Idx<T>;

    fn next(&mut self) -> Option<Self::Item> {
        self.range.next().map(|raw| Idx::from_raw(raw.into()))
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        self.range.size_hint()
    }

    fn count(self) -> usize
    where
        Self: Sized,
    {
        self.range.count()
    }

    fn last(self) -> Option<Self::Item>
    where
        Self: Sized,
    {
        self.range.last().map(|raw| Idx::from_raw(raw.into()))
    }

    fn nth(&mut self, n: usize) -> Option<Self::Item> {
        self.range.nth(n).map(|raw| Idx::from_raw(raw.into()))
    }
}

impl<T> DoubleEndedIterator for IdxRange<T> {
    fn next_back(&mut self) -> Option<Self::Item> {
        self.range.next_back().map(|raw| Idx::from_raw(raw.into()))
    }
}

impl<T> ExactSizeIterator for IdxRange<T> {}

impl<T> FusedIterator for IdxRange<T> {}

impl<T> fmt::Debug for IdxRange<T> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_tuple(&format!("IdxRange::<{}>", std::any::type_name::<T>()))
            .field(&self.range)
            .finish()
    }
}

impl<T> Clone for IdxRange<T> {
    fn clone(&self) -> Self {
        Self { range: self.range.clone(), _p: PhantomData }
    }
}

impl<T> PartialEq for IdxRange<T> {
    fn eq(&self, other: &Self) -> bool {
        self.range == other.range
    }
}

impl<T> Eq for IdxRange<T> {}

/// Yet another index-based arena.
#[derive(Clone, PartialEq, Eq, Hash)]
pub struct Arena<T> {
    data: Vec<T>,
}

impl<T: fmt::Debug> fmt::Debug for Arena<T> {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_struct("Arena").field("len", &self.len()).field("data", &self.data).finish()
    }
}

impl<T> Arena<T> {
    /// Creates a new empty arena.
    ///
    /// ```
    /// let arena: la_arena::Arena<i32> = la_arena::Arena::new();
    /// assert!(arena.is_empty());
    /// ```
    pub const fn new() -> Arena<T> {
        Arena { data: Vec::new() }
    }

    /// Create a new empty arena with specific capacity.
    ///
    /// ```
    /// let arena: la_arena::Arena<i32> = la_arena::Arena::with_capacity(42);
    /// assert!(arena.is_empty());
    /// ```
    pub fn with_capacity(capacity: usize) -> Arena<T> {
        Arena { data: Vec::with_capacity(capacity) }
    }

    /// Empties the arena, removing all contained values.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    ///
    /// arena.alloc(1);
    /// arena.alloc(2);
    /// arena.alloc(3);
    /// assert_eq!(arena.len(), 3);
    ///
    /// arena.clear();
    /// assert!(arena.is_empty());
    /// ```
    pub fn clear(&mut self) {
        self.data.clear();
    }

    /// Returns the length of the arena.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// assert_eq!(arena.len(), 0);
    ///
    /// arena.alloc("foo");
    /// assert_eq!(arena.len(), 1);
    ///
    /// arena.alloc("bar");
    /// assert_eq!(arena.len(), 2);
    ///
    /// arena.alloc("baz");
    /// assert_eq!(arena.len(), 3);
    /// ```
    pub fn len(&self) -> usize {
        self.data.len()
    }

    /// Returns whether the arena contains no elements.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// assert!(arena.is_empty());
    ///
    /// arena.alloc(0.5);
    /// assert!(!arena.is_empty());
    /// ```
    pub fn is_empty(&self) -> bool {
        self.data.is_empty()
    }

    /// Allocates a new value on the arena, returning the value’s index.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// let idx = arena.alloc(50);
    ///
    /// assert_eq!(arena[idx], 50);
    /// ```
    pub fn alloc(&mut self, value: T) -> Idx<T> {
        let idx = self.next_idx();
        self.data.push(value);
        idx
    }

    /// Densely allocates multiple values, returning the values’ index range.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// let range = arena.alloc_many(0..4);
    ///
    /// assert_eq!(arena[range], [0, 1, 2, 3]);
    /// ```
    pub fn alloc_many<II: IntoIterator<Item = T>>(&mut self, iter: II) -> IdxRange<T> {
        let start = self.next_idx();
        self.extend(iter);
        let end = self.next_idx();
        IdxRange::new(start..end)
    }

    /// Returns an iterator over the arena’s elements.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// let idx1 = arena.alloc(20);
    /// let idx2 = arena.alloc(40);
    /// let idx3 = arena.alloc(60);
    ///
    /// let mut iterator = arena.iter();
    /// assert_eq!(iterator.next(), Some((idx1, &20)));
    /// assert_eq!(iterator.next(), Some((idx2, &40)));
    /// assert_eq!(iterator.next(), Some((idx3, &60)));
    /// ```
    pub fn iter(
        &self,
    ) -> impl Iterator<Item = (Idx<T>, &T)> + ExactSizeIterator + DoubleEndedIterator + Clone {
        self.data.iter().enumerate().map(|(idx, value)| (Idx::from_raw(RawIdx(idx as u32)), value))
    }

    /// Returns an iterator over the arena’s mutable elements.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// let idx1 = arena.alloc(20);
    ///
    /// assert_eq!(arena[idx1], 20);
    ///
    /// let mut iterator = arena.iter_mut();
    /// *iterator.next().unwrap().1 = 10;
    /// drop(iterator);
    ///
    /// assert_eq!(arena[idx1], 10);
    /// ```
    pub fn iter_mut(
        &mut self,
    ) -> impl Iterator<Item = (Idx<T>, &mut T)> + ExactSizeIterator + DoubleEndedIterator {
        self.data
            .iter_mut()
            .enumerate()
            .map(|(idx, value)| (Idx::from_raw(RawIdx(idx as u32)), value))
    }

    /// Returns an iterator over the arena’s values.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// let idx1 = arena.alloc(20);
    /// let idx2 = arena.alloc(40);
    /// let idx3 = arena.alloc(60);
    ///
    /// let mut iterator = arena.values();
    /// assert_eq!(iterator.next(), Some(&20));
    /// assert_eq!(iterator.next(), Some(&40));
    /// assert_eq!(iterator.next(), Some(&60));
    /// ```
    pub fn values(&self) -> impl Iterator<Item = &T> + ExactSizeIterator + DoubleEndedIterator {
        self.data.iter()
    }

    /// Returns an iterator over the arena’s mutable values.
    ///
    /// ```
    /// let mut arena = la_arena::Arena::new();
    /// let idx1 = arena.alloc(20);
    ///
    /// assert_eq!(arena[idx1], 20);
    ///
    /// let mut iterator = arena.values_mut();
    /// *iterator.next().unwrap() = 10;
    /// drop(iterator);
    ///
    /// assert_eq!(arena[idx1], 10);
    /// ```
    pub fn values_mut(
        &mut self,
    ) -> impl Iterator<Item = &mut T> + ExactSizeIterator + DoubleEndedIterator {
        self.data.iter_mut()
    }

    /// Reallocates the arena to make it take up as little space as possible.
    pub fn shrink_to_fit(&mut self) {
        self.data.shrink_to_fit();
    }

    /// Returns the index of the next value allocated on the arena.
    ///
    /// This method should remain private to make creating invalid `Idx`s harder.
    fn next_idx(&self) -> Idx<T> {
        Idx::from_raw(RawIdx(self.data.len() as u32))
    }
}

impl<T> AsMut<[T]> for Arena<T> {
    fn as_mut(&mut self) -> &mut [T] {
        self.data.as_mut()
    }
}

impl<T> Default for Arena<T> {
    fn default() -> Arena<T> {
        Arena { data: Vec::new() }
    }
}

impl<T> Index<Idx<T>> for Arena<T> {
    type Output = T;
    fn index(&self, idx: Idx<T>) -> &T {
        let idx = idx.into_raw().0 as usize;
        &self.data[idx]
    }
}

impl<T> IndexMut<Idx<T>> for Arena<T> {
    fn index_mut(&mut self, idx: Idx<T>) -> &mut T {
        let idx = idx.into_raw().0 as usize;
        &mut self.data[idx]
    }
}

impl<T> Index<IdxRange<T>> for Arena<T> {
    type Output = [T];
    fn index(&self, range: IdxRange<T>) -> &[T] {
        let start = range.range.start as usize;
        let end = range.range.end as usize;
        &self.data[start..end]
    }
}

impl<T> FromIterator<T> for Arena<T> {
    fn from_iter<I>(iter: I) -> Self
    where
        I: IntoIterator<Item = T>,
    {
        Arena { data: Vec::from_iter(iter) }
    }
}

/// An iterator over the arena’s elements.
pub struct IntoIter<T>(Enumerate<<Vec<T> as IntoIterator>::IntoIter>);

impl<T> Iterator for IntoIter<T> {
    type Item = (Idx<T>, T);

    fn next(&mut self) -> Option<Self::Item> {
        self.0.next().map(|(idx, value)| (Idx::from_raw(RawIdx(idx as u32)), value))
    }
}

impl<T> IntoIterator for Arena<T> {
    type Item = (Idx<T>, T);

    type IntoIter = IntoIter<T>;

    fn into_iter(self) -> Self::IntoIter {
        IntoIter(self.data.into_iter().enumerate())
    }
}

impl<T> Extend<T> for Arena<T> {
    fn extend<II: IntoIterator<Item = T>>(&mut self, iter: II) {
        for t in iter {
            self.alloc(t);
        }
    }
}