1//! Opt-in access to the experimental raw entry API.
2//!
3//! This module is designed to mimic the raw entry API of [`HashMap`][std::collections::hash_map],
4//! matching its unstable state as of Rust 1.75. See the tracking issue
5//! [rust#56167](https://github.com/rust-lang/rust/issues/56167) for more details.
6//!
7//! The trait [`RawEntryApiV1`] and the `_v1` suffix on its methods are meant to insulate this for
8//! the future, in case later breaking changes are needed. If the standard library stabilizes its
9//! `hash_raw_entry` feature (or some replacement), matching *inherent* methods will be added to
10//! `IndexMap` without such an opt-in trait.
11
12use super::{Entries, RefMut};
13use crate::{Equivalent, HashValue, IndexMap};
14use core::fmt;
15use core::hash::{BuildHasher, Hash, Hasher};
16use core::marker::PhantomData;
17use core::mem;
18use hashbrown::hash_table;
19
20/// Opt-in access to the experimental raw entry API.
21///
22/// See the [`raw_entry_v1`][self] module documentation for more information.
23pub trait RawEntryApiV1<K, V, S>: private::Sealed {
24 /// Creates a raw immutable entry builder for the [`IndexMap`].
25 ///
26 /// Raw entries provide the lowest level of control for searching and
27 /// manipulating a map. They must be manually initialized with a hash and
28 /// then manually searched.
29 ///
30 /// This is useful for
31 /// * Hash memoization
32 /// * Using a search key that doesn't work with the [`Equivalent`] trait
33 /// * Using custom comparison logic without newtype wrappers
34 ///
35 /// Unless you are in such a situation, higher-level and more foolproof APIs like
36 /// [`get`][IndexMap::get] should be preferred.
37 ///
38 /// Immutable raw entries have very limited use; you might instead want
39 /// [`raw_entry_mut_v1`][Self::raw_entry_mut_v1].
40 ///
41 /// # Examples
42 ///
43 /// ```
44 /// use core::hash::{BuildHasher, Hash};
45 /// use indexmap::map::{IndexMap, RawEntryApiV1};
46 ///
47 /// let mut map = IndexMap::new();
48 /// map.extend([("a", 100), ("b", 200), ("c", 300)]);
49 ///
50 /// fn compute_hash<K: Hash + ?Sized, S: BuildHasher>(hash_builder: &S, key: &K) -> u64 {
51 /// use core::hash::Hasher;
52 /// let mut state = hash_builder.build_hasher();
53 /// key.hash(&mut state);
54 /// state.finish()
55 /// }
56 ///
57 /// for k in ["a", "b", "c", "d", "e", "f"] {
58 /// let hash = compute_hash(map.hasher(), k);
59 /// let i = map.get_index_of(k);
60 /// let v = map.get(k);
61 /// let kv = map.get_key_value(k);
62 /// let ikv = map.get_full(k);
63 ///
64 /// println!("Key: {} and value: {:?}", k, v);
65 ///
66 /// assert_eq!(map.raw_entry_v1().from_key(k), kv);
67 /// assert_eq!(map.raw_entry_v1().from_hash(hash, |q| *q == k), kv);
68 /// assert_eq!(map.raw_entry_v1().from_key_hashed_nocheck(hash, k), kv);
69 /// assert_eq!(map.raw_entry_v1().from_hash_full(hash, |q| *q == k), ikv);
70 /// assert_eq!(map.raw_entry_v1().index_from_hash(hash, |q| *q == k), i);
71 /// }
72 /// ```
73 fn raw_entry_v1(&self) -> RawEntryBuilder<'_, K, V, S>;
74
75 /// Creates a raw entry builder for the [`IndexMap`].
76 ///
77 /// Raw entries provide the lowest level of control for searching and
78 /// manipulating a map. They must be manually initialized with a hash and
79 /// then manually searched. After this, insertions into a vacant entry
80 /// still require an owned key to be provided.
81 ///
82 /// Raw entries are useful for such exotic situations as:
83 ///
84 /// * Hash memoization
85 /// * Deferring the creation of an owned key until it is known to be required
86 /// * Using a search key that doesn't work with the [`Equivalent`] trait
87 /// * Using custom comparison logic without newtype wrappers
88 ///
89 /// Because raw entries provide much more low-level control, it's much easier
90 /// to put the `IndexMap` into an inconsistent state which, while memory-safe,
91 /// will cause the map to produce seemingly random results. Higher-level and more
92 /// foolproof APIs like [`entry`][IndexMap::entry] should be preferred when possible.
93 ///
94 /// Raw entries give mutable access to the keys. This must not be used
95 /// to modify how the key would compare or hash, as the map will not re-evaluate
96 /// where the key should go, meaning the keys may become "lost" if their
97 /// location does not reflect their state. For instance, if you change a key
98 /// so that the map now contains keys which compare equal, search may start
99 /// acting erratically, with two keys randomly masking each other. Implementations
100 /// are free to assume this doesn't happen (within the limits of memory-safety).
101 ///
102 /// # Examples
103 ///
104 /// ```
105 /// use core::hash::{BuildHasher, Hash};
106 /// use indexmap::map::{IndexMap, RawEntryApiV1};
107 /// use indexmap::map::raw_entry_v1::RawEntryMut;
108 ///
109 /// let mut map = IndexMap::new();
110 /// map.extend([("a", 100), ("b", 200), ("c", 300)]);
111 ///
112 /// fn compute_hash<K: Hash + ?Sized, S: BuildHasher>(hash_builder: &S, key: &K) -> u64 {
113 /// use core::hash::Hasher;
114 /// let mut state = hash_builder.build_hasher();
115 /// key.hash(&mut state);
116 /// state.finish()
117 /// }
118 ///
119 /// // Existing key (insert and update)
120 /// match map.raw_entry_mut_v1().from_key("a") {
121 /// RawEntryMut::Vacant(_) => unreachable!(),
122 /// RawEntryMut::Occupied(mut view) => {
123 /// assert_eq!(view.index(), 0);
124 /// assert_eq!(view.get(), &100);
125 /// let v = view.get_mut();
126 /// let new_v = (*v) * 10;
127 /// *v = new_v;
128 /// assert_eq!(view.insert(1111), 1000);
129 /// }
130 /// }
131 ///
132 /// assert_eq!(map["a"], 1111);
133 /// assert_eq!(map.len(), 3);
134 ///
135 /// // Existing key (take)
136 /// let hash = compute_hash(map.hasher(), "c");
137 /// match map.raw_entry_mut_v1().from_key_hashed_nocheck(hash, "c") {
138 /// RawEntryMut::Vacant(_) => unreachable!(),
139 /// RawEntryMut::Occupied(view) => {
140 /// assert_eq!(view.index(), 2);
141 /// assert_eq!(view.shift_remove_entry(), ("c", 300));
142 /// }
143 /// }
144 /// assert_eq!(map.raw_entry_v1().from_key("c"), None);
145 /// assert_eq!(map.len(), 2);
146 ///
147 /// // Nonexistent key (insert and update)
148 /// let key = "d";
149 /// let hash = compute_hash(map.hasher(), key);
150 /// match map.raw_entry_mut_v1().from_hash(hash, |q| *q == key) {
151 /// RawEntryMut::Occupied(_) => unreachable!(),
152 /// RawEntryMut::Vacant(view) => {
153 /// assert_eq!(view.index(), 2);
154 /// let (k, value) = view.insert("d", 4000);
155 /// assert_eq!((*k, *value), ("d", 4000));
156 /// *value = 40000;
157 /// }
158 /// }
159 /// assert_eq!(map["d"], 40000);
160 /// assert_eq!(map.len(), 3);
161 ///
162 /// match map.raw_entry_mut_v1().from_hash(hash, |q| *q == key) {
163 /// RawEntryMut::Vacant(_) => unreachable!(),
164 /// RawEntryMut::Occupied(view) => {
165 /// assert_eq!(view.index(), 2);
166 /// assert_eq!(view.swap_remove_entry(), ("d", 40000));
167 /// }
168 /// }
169 /// assert_eq!(map.get("d"), None);
170 /// assert_eq!(map.len(), 2);
171 /// ```
172 fn raw_entry_mut_v1(&mut self) -> RawEntryBuilderMut<'_, K, V, S>;
173}
174
175impl<K, V, S> RawEntryApiV1<K, V, S> for IndexMap<K, V, S> {
176 fn raw_entry_v1(&self) -> RawEntryBuilder<'_, K, V, S> {
177 RawEntryBuilder { map: self }
178 }
179
180 fn raw_entry_mut_v1(&mut self) -> RawEntryBuilderMut<'_, K, V, S> {
181 RawEntryBuilderMut { map: self }
182 }
183}
184
185/// A builder for computing where in an [`IndexMap`] a key-value pair would be stored.
186///
187/// This `struct` is created by the [`IndexMap::raw_entry_v1`] method, provided by the
188/// [`RawEntryApiV1`] trait. See its documentation for more.
189pub struct RawEntryBuilder<'a, K, V, S> {
190 map: &'a IndexMap<K, V, S>,
191}
192
193impl<K, V, S> fmt::Debug for RawEntryBuilder<'_, K, V, S> {
194 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
195 f.debug_struct(name:"RawEntryBuilder").finish_non_exhaustive()
196 }
197}
198
199impl<'a, K, V, S> RawEntryBuilder<'a, K, V, S> {
200 /// Access an entry by key.
201 pub fn from_key<Q>(self, key: &Q) -> Option<(&'a K, &'a V)>
202 where
203 S: BuildHasher,
204 Q: ?Sized + Hash + Equivalent<K>,
205 {
206 self.map.get_key_value(key)
207 }
208
209 /// Access an entry by a key and its hash.
210 pub fn from_key_hashed_nocheck<Q>(self, hash: u64, key: &Q) -> Option<(&'a K, &'a V)>
211 where
212 Q: ?Sized + Equivalent<K>,
213 {
214 let hash = HashValue(hash as usize);
215 let i = self.map.core.get_index_of(hash, key)?;
216 self.map.get_index(i)
217 }
218
219 /// Access an entry by hash.
220 pub fn from_hash<F>(self, hash: u64, is_match: F) -> Option<(&'a K, &'a V)>
221 where
222 F: FnMut(&K) -> bool,
223 {
224 let map = self.map;
225 let i = self.index_from_hash(hash, is_match)?;
226 map.get_index(i)
227 }
228
229 /// Access an entry by hash, including its index.
230 pub fn from_hash_full<F>(self, hash: u64, is_match: F) -> Option<(usize, &'a K, &'a V)>
231 where
232 F: FnMut(&K) -> bool,
233 {
234 let map = self.map;
235 let i = self.index_from_hash(hash, is_match)?;
236 let (key, value) = map.get_index(i)?;
237 Some((i, key, value))
238 }
239
240 /// Access the index of an entry by hash.
241 pub fn index_from_hash<F>(self, hash: u64, mut is_match: F) -> Option<usize>
242 where
243 F: FnMut(&K) -> bool,
244 {
245 let hash = HashValue(hash as usize);
246 let entries = &*self.map.core.entries;
247 let eq = move |&i: &usize| is_match(&entries[i].key);
248 self.map.core.indices.find(hash.get(), eq).copied()
249 }
250}
251
252/// A builder for computing where in an [`IndexMap`] a key-value pair would be stored.
253///
254/// This `struct` is created by the [`IndexMap::raw_entry_mut_v1`] method, provided by the
255/// [`RawEntryApiV1`] trait. See its documentation for more.
256pub struct RawEntryBuilderMut<'a, K, V, S> {
257 map: &'a mut IndexMap<K, V, S>,
258}
259
260impl<K, V, S> fmt::Debug for RawEntryBuilderMut<'_, K, V, S> {
261 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
262 f.debug_struct(name:"RawEntryBuilderMut").finish_non_exhaustive()
263 }
264}
265
266impl<'a, K, V, S> RawEntryBuilderMut<'a, K, V, S> {
267 /// Access an entry by key.
268 pub fn from_key<Q>(self, key: &Q) -> RawEntryMut<'a, K, V, S>
269 where
270 S: BuildHasher,
271 Q: ?Sized + Hash + Equivalent<K>,
272 {
273 let hash = self.map.hash(key);
274 self.from_key_hashed_nocheck(hash.get(), key)
275 }
276
277 /// Access an entry by a key and its hash.
278 pub fn from_key_hashed_nocheck<Q>(self, hash: u64, key: &Q) -> RawEntryMut<'a, K, V, S>
279 where
280 Q: ?Sized + Equivalent<K>,
281 {
282 self.from_hash(hash, |k| Q::equivalent(key, k))
283 }
284
285 /// Access an entry by hash.
286 pub fn from_hash<F>(self, hash: u64, mut is_match: F) -> RawEntryMut<'a, K, V, S>
287 where
288 F: FnMut(&K) -> bool,
289 {
290 let ref_entries = &*self.map.core.entries;
291 let eq = move |&i: &usize| is_match(&ref_entries[i].key);
292 match self.map.core.indices.find_entry(hash, eq) {
293 Ok(index) => RawEntryMut::Occupied(RawOccupiedEntryMut {
294 entries: &mut self.map.core.entries,
295 index,
296 hash_builder: PhantomData,
297 }),
298 Err(absent) => RawEntryMut::Vacant(RawVacantEntryMut {
299 map: RefMut::new(absent.into_table(), &mut self.map.core.entries),
300 hash_builder: &self.map.hash_builder,
301 }),
302 }
303 }
304}
305
306/// Raw entry for an existing key-value pair or a vacant location to
307/// insert one.
308pub enum RawEntryMut<'a, K, V, S> {
309 /// Existing slot with equivalent key.
310 Occupied(RawOccupiedEntryMut<'a, K, V, S>),
311 /// Vacant slot (no equivalent key in the map).
312 Vacant(RawVacantEntryMut<'a, K, V, S>),
313}
314
315impl<K: fmt::Debug, V: fmt::Debug, S> fmt::Debug for RawEntryMut<'_, K, V, S> {
316 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
317 let mut tuple: DebugTuple<'_, '_> = f.debug_tuple(name:"RawEntryMut");
318 match self {
319 Self::Vacant(v: &RawVacantEntryMut<'_, K, …, …>) => tuple.field(v),
320 Self::Occupied(o: &RawOccupiedEntryMut<'_, K, …, …>) => tuple.field(o),
321 };
322 tuple.finish()
323 }
324}
325
326impl<'a, K, V, S> RawEntryMut<'a, K, V, S> {
327 /// Return the index where the key-value pair exists or may be inserted.
328 #[inline]
329 pub fn index(&self) -> usize {
330 match self {
331 Self::Occupied(entry) => entry.index(),
332 Self::Vacant(entry) => entry.index(),
333 }
334 }
335
336 /// Inserts the given default key and value in the entry if it is vacant and returns mutable
337 /// references to them. Otherwise mutable references to an already existent pair are returned.
338 pub fn or_insert(self, default_key: K, default_value: V) -> (&'a mut K, &'a mut V)
339 where
340 K: Hash,
341 S: BuildHasher,
342 {
343 match self {
344 Self::Occupied(entry) => entry.into_key_value_mut(),
345 Self::Vacant(entry) => entry.insert(default_key, default_value),
346 }
347 }
348
349 /// Inserts the result of the `call` function in the entry if it is vacant and returns mutable
350 /// references to them. Otherwise mutable references to an already existent pair are returned.
351 pub fn or_insert_with<F>(self, call: F) -> (&'a mut K, &'a mut V)
352 where
353 F: FnOnce() -> (K, V),
354 K: Hash,
355 S: BuildHasher,
356 {
357 match self {
358 Self::Occupied(entry) => entry.into_key_value_mut(),
359 Self::Vacant(entry) => {
360 let (key, value) = call();
361 entry.insert(key, value)
362 }
363 }
364 }
365
366 /// Modifies the entry if it is occupied.
367 pub fn and_modify<F>(mut self, f: F) -> Self
368 where
369 F: FnOnce(&mut K, &mut V),
370 {
371 if let Self::Occupied(entry) = &mut self {
372 let (k, v) = entry.get_key_value_mut();
373 f(k, v);
374 }
375 self
376 }
377}
378
379/// A raw view into an occupied entry in an [`IndexMap`].
380/// It is part of the [`RawEntryMut`] enum.
381pub struct RawOccupiedEntryMut<'a, K, V, S> {
382 entries: &'a mut Entries<K, V>,
383 index: hash_table::OccupiedEntry<'a, usize>,
384 hash_builder: PhantomData<&'a S>,
385}
386
387impl<K: fmt::Debug, V: fmt::Debug, S> fmt::Debug for RawOccupiedEntryMut<'_, K, V, S> {
388 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
389 f&mut DebugStruct<'_, '_>.debug_struct("RawOccupiedEntryMut")
390 .field("key", self.key())
391 .field(name:"value", self.get())
392 .finish_non_exhaustive()
393 }
394}
395
396impl<'a, K, V, S> RawOccupiedEntryMut<'a, K, V, S> {
397 /// Return the index of the key-value pair
398 #[inline]
399 pub fn index(&self) -> usize {
400 *self.index.get()
401 }
402
403 #[inline]
404 fn into_ref_mut(self) -> RefMut<'a, K, V> {
405 RefMut::new(self.index.into_table(), self.entries)
406 }
407
408 /// Gets a reference to the entry's key in the map.
409 ///
410 /// Note that this is not the key that was used to find the entry. There may be an observable
411 /// difference if the key type has any distinguishing features outside of `Hash` and `Eq`, like
412 /// extra fields or the memory address of an allocation.
413 pub fn key(&self) -> &K {
414 &self.entries[self.index()].key
415 }
416
417 /// Gets a mutable reference to the entry's key in the map.
418 ///
419 /// Note that this is not the key that was used to find the entry. There may be an observable
420 /// difference if the key type has any distinguishing features outside of `Hash` and `Eq`, like
421 /// extra fields or the memory address of an allocation.
422 pub fn key_mut(&mut self) -> &mut K {
423 let index = self.index();
424 &mut self.entries[index].key
425 }
426
427 /// Converts into a mutable reference to the entry's key in the map,
428 /// with a lifetime bound to the map itself.
429 ///
430 /// Note that this is not the key that was used to find the entry. There may be an observable
431 /// difference if the key type has any distinguishing features outside of `Hash` and `Eq`, like
432 /// extra fields or the memory address of an allocation.
433 pub fn into_key(self) -> &'a mut K {
434 let index = self.index();
435 &mut self.entries[index].key
436 }
437
438 /// Gets a reference to the entry's value in the map.
439 pub fn get(&self) -> &V {
440 &self.entries[self.index()].value
441 }
442
443 /// Gets a mutable reference to the entry's value in the map.
444 ///
445 /// If you need a reference which may outlive the destruction of the
446 /// [`RawEntryMut`] value, see [`into_mut`][Self::into_mut].
447 pub fn get_mut(&mut self) -> &mut V {
448 let index = self.index();
449 &mut self.entries[index].value
450 }
451
452 /// Converts into a mutable reference to the entry's value in the map,
453 /// with a lifetime bound to the map itself.
454 pub fn into_mut(self) -> &'a mut V {
455 let index = self.index();
456 &mut self.entries[index].value
457 }
458
459 /// Gets a reference to the entry's key and value in the map.
460 pub fn get_key_value(&self) -> (&K, &V) {
461 self.entries[self.index()].refs()
462 }
463
464 /// Gets a reference to the entry's key and value in the map.
465 pub fn get_key_value_mut(&mut self) -> (&mut K, &mut V) {
466 let index = self.index();
467 self.entries[index].muts()
468 }
469
470 /// Converts into a mutable reference to the entry's key and value in the map,
471 /// with a lifetime bound to the map itself.
472 pub fn into_key_value_mut(self) -> (&'a mut K, &'a mut V) {
473 let index = self.index();
474 self.entries[index].muts()
475 }
476
477 /// Sets the value of the entry, and returns the entry's old value.
478 pub fn insert(&mut self, value: V) -> V {
479 mem::replace(self.get_mut(), value)
480 }
481
482 /// Sets the key of the entry, and returns the entry's old key.
483 pub fn insert_key(&mut self, key: K) -> K {
484 mem::replace(self.key_mut(), key)
485 }
486
487 /// Remove the key, value pair stored in the map for this entry, and return the value.
488 ///
489 /// **NOTE:** This is equivalent to [`.swap_remove()`][Self::swap_remove], replacing this
490 /// entry's position with the last element, and it is deprecated in favor of calling that
491 /// explicitly. If you need to preserve the relative order of the keys in the map, use
492 /// [`.shift_remove()`][Self::shift_remove] instead.
493 #[deprecated(note = "`remove` disrupts the map order -- \
494 use `swap_remove` or `shift_remove` for explicit behavior.")]
495 pub fn remove(self) -> V {
496 self.swap_remove()
497 }
498
499 /// Remove the key, value pair stored in the map for this entry, and return the value.
500 ///
501 /// Like [`Vec::swap_remove`][crate::Vec::swap_remove], the pair is removed by swapping it with
502 /// the last element of the map and popping it off.
503 /// **This perturbs the position of what used to be the last element!**
504 ///
505 /// Computes in **O(1)** time (average).
506 pub fn swap_remove(self) -> V {
507 self.swap_remove_entry().1
508 }
509
510 /// Remove the key, value pair stored in the map for this entry, and return the value.
511 ///
512 /// Like [`Vec::remove`][crate::Vec::remove], the pair is removed by shifting all of the
513 /// elements that follow it, preserving their relative order.
514 /// **This perturbs the index of all of those elements!**
515 ///
516 /// Computes in **O(n)** time (average).
517 pub fn shift_remove(self) -> V {
518 self.shift_remove_entry().1
519 }
520
521 /// Remove and return the key, value pair stored in the map for this entry
522 ///
523 /// **NOTE:** This is equivalent to [`.swap_remove_entry()`][Self::swap_remove_entry],
524 /// replacing this entry's position with the last element, and it is deprecated in favor of
525 /// calling that explicitly. If you need to preserve the relative order of the keys in the map,
526 /// use [`.shift_remove_entry()`][Self::shift_remove_entry] instead.
527 #[deprecated(note = "`remove_entry` disrupts the map order -- \
528 use `swap_remove_entry` or `shift_remove_entry` for explicit behavior.")]
529 pub fn remove_entry(self) -> (K, V) {
530 self.swap_remove_entry()
531 }
532
533 /// Remove and return the key, value pair stored in the map for this entry
534 ///
535 /// Like [`Vec::swap_remove`][crate::Vec::swap_remove], the pair is removed by swapping it with
536 /// the last element of the map and popping it off.
537 /// **This perturbs the position of what used to be the last element!**
538 ///
539 /// Computes in **O(1)** time (average).
540 pub fn swap_remove_entry(self) -> (K, V) {
541 let (index, entry) = self.index.remove();
542 RefMut::new(entry.into_table(), self.entries).swap_remove_finish(index)
543 }
544
545 /// Remove and return the key, value pair stored in the map for this entry
546 ///
547 /// Like [`Vec::remove`][crate::Vec::remove], the pair is removed by shifting all of the
548 /// elements that follow it, preserving their relative order.
549 /// **This perturbs the index of all of those elements!**
550 ///
551 /// Computes in **O(n)** time (average).
552 pub fn shift_remove_entry(self) -> (K, V) {
553 let (index, entry) = self.index.remove();
554 RefMut::new(entry.into_table(), self.entries).shift_remove_finish(index)
555 }
556
557 /// Moves the position of the entry to a new index
558 /// by shifting all other entries in-between.
559 ///
560 /// This is equivalent to [`IndexMap::move_index`]
561 /// coming `from` the current [`.index()`][Self::index].
562 ///
563 /// * If `self.index() < to`, the other pairs will shift down while the targeted pair moves up.
564 /// * If `self.index() > to`, the other pairs will shift up while the targeted pair moves down.
565 ///
566 /// ***Panics*** if `to` is out of bounds.
567 ///
568 /// Computes in **O(n)** time (average).
569 pub fn move_index(self, to: usize) {
570 let index = self.index();
571 self.into_ref_mut().move_index(index, to);
572 }
573
574 /// Swaps the position of entry with another.
575 ///
576 /// This is equivalent to [`IndexMap::swap_indices`]
577 /// with the current [`.index()`][Self::index] as one of the two being swapped.
578 ///
579 /// ***Panics*** if the `other` index is out of bounds.
580 ///
581 /// Computes in **O(1)** time (average).
582 pub fn swap_indices(self, other: usize) {
583 let index = self.index();
584 self.into_ref_mut().swap_indices(index, other);
585 }
586}
587
588/// A view into a vacant raw entry in an [`IndexMap`].
589/// It is part of the [`RawEntryMut`] enum.
590pub struct RawVacantEntryMut<'a, K, V, S> {
591 map: RefMut<'a, K, V>,
592 hash_builder: &'a S,
593}
594
595impl<K, V, S> fmt::Debug for RawVacantEntryMut<'_, K, V, S> {
596 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
597 f.debug_struct(name:"RawVacantEntryMut").finish_non_exhaustive()
598 }
599}
600
601impl<'a, K, V, S> RawVacantEntryMut<'a, K, V, S> {
602 /// Return the index where a key-value pair may be inserted.
603 pub fn index(&self) -> usize {
604 self.map.indices.len()
605 }
606
607 /// Inserts the given key and value into the map,
608 /// and returns mutable references to them.
609 pub fn insert(self, key: K, value: V) -> (&'a mut K, &'a mut V)
610 where
611 K: Hash,
612 S: BuildHasher,
613 {
614 let mut h = self.hash_builder.build_hasher();
615 key.hash(&mut h);
616 self.insert_hashed_nocheck(h.finish(), key, value)
617 }
618
619 /// Inserts the given key and value into the map with the provided hash,
620 /// and returns mutable references to them.
621 pub fn insert_hashed_nocheck(self, hash: u64, key: K, value: V) -> (&'a mut K, &'a mut V) {
622 let hash = HashValue(hash as usize);
623 self.map.insert_unique(hash, key, value).into_muts()
624 }
625
626 /// Inserts the given key and value into the map at the given index,
627 /// shifting others to the right, and returns mutable references to them.
628 ///
629 /// ***Panics*** if `index` is out of bounds.
630 ///
631 /// Computes in **O(n)** time (average).
632 pub fn shift_insert(self, index: usize, key: K, value: V) -> (&'a mut K, &'a mut V)
633 where
634 K: Hash,
635 S: BuildHasher,
636 {
637 let mut h = self.hash_builder.build_hasher();
638 key.hash(&mut h);
639 self.shift_insert_hashed_nocheck(index, h.finish(), key, value)
640 }
641
642 /// Inserts the given key and value into the map with the provided hash
643 /// at the given index, and returns mutable references to them.
644 ///
645 /// ***Panics*** if `index` is out of bounds.
646 ///
647 /// Computes in **O(n)** time (average).
648 pub fn shift_insert_hashed_nocheck(
649 mut self,
650 index: usize,
651 hash: u64,
652 key: K,
653 value: V,
654 ) -> (&'a mut K, &'a mut V) {
655 let hash = HashValue(hash as usize);
656 self.map.shift_insert_unique(index, hash, key, value);
657 self.map.entries[index].muts()
658 }
659}
660
661mod private {
662 pub trait Sealed {}
663
664 impl<K, V, S> Sealed for super::IndexMap<K, V, S> {}
665}
666