0094b3412726fc99517f70868677e39b59f3d5cc
1 //! The raw form of a `Map`, allowing untyped access.
3 //! All relevant details are in the `RawMap` struct.
6 use std
::borrow
::Borrow
;
7 use std
::collections
::hash_map
::{self, HashMap
};
8 use std
::convert
::TryInto
;
10 use std
::hash
::{Hasher
, BuildHasherDefault
};
13 use std
::ops
::{Index
, IndexMut
};
15 use any
::{Any
, UncheckedAnyExt
};
22 impl Hasher
for TypeIdHasher
{
24 fn write(&mut self, bytes
: &[u8]) {
25 // This expects to receive exactly one 64-bit value, and there’s no realistic chance of
26 // that changing, but I don’t want to depend on something that isn’t expressly part of the
27 // contract for safety. But I’m OK with release builds putting everything in one bucket
28 // if it *did* change (and debug builds panicking).
29 debug_assert_eq!(bytes
.len(), 8);
30 let _
= bytes
.try_into()
31 .map(|array
| self.value
= u64::from_ne_bytes(array
));
35 fn finish(&self) -> u64 { self.value
}
40 fn verify_hashing_with(type_id
: TypeId
) {
41 let mut hasher
= TypeIdHasher
::default();
42 type_id
.hash(&mut hasher
);
43 assert_eq!(hasher
.finish(), unsafe { mem
::transmute
::<TypeId
, u64>(type_id
) });
45 // Pick a variety of types, just to demonstrate it’s all sane. Normal, zero-sized, unsized, &c.
46 verify_hashing_with(TypeId
::of
::<usize>());
47 verify_hashing_with(TypeId
::of
::<()>());
48 verify_hashing_with(TypeId
::of
::<str>());
49 verify_hashing_with(TypeId
::of
::<&str>());
50 verify_hashing_with(TypeId
::of
::<Vec
<u8>>());
53 /// The raw, underlying form of a `Map`.
55 /// At its essence, this is a wrapper around `HashMap<TypeId, Box<Any>>`, with the portions that
56 /// would be memory-unsafe removed or marked unsafe. Normal people are expected to use the safe
57 /// `Map` interface instead, but there is the occasional use for this such as iteration over the
58 /// contents of an `Map`. However, because you will then be dealing with `Any` trait objects, it
59 /// doesn’t tend to be so very useful. Still, if you need it, it’s here.
61 pub struct RawMap
<A
: ?Sized
+ UncheckedAnyExt
= dyn Any
> {
62 inner
: HashMap
<TypeId
, Box
<A
>, BuildHasherDefault
<TypeIdHasher
>>,
65 // #[derive(Clone)] would want A to implement Clone, but in reality it’s only Box<A> that can.
66 impl<A
: ?Sized
+ UncheckedAnyExt
> Clone
for RawMap
<A
> where Box
<A
>: Clone
{
68 fn clone(&self) -> RawMap
<A
> {
70 inner
: self.inner
.clone(),
75 impl_common_methods
! {
77 new() => HashMap
::with_hasher(Default
::default());
78 with_capacity(capacity
) => HashMap
::with_capacity_and_hasher(capacity
, Default
::default());
81 /// `RawMap` iterator.
83 pub struct Iter
<'a
, A
: ?Sized
+ UncheckedAnyExt
> {
84 inner
: hash_map
::Iter
<'a
, TypeId
, Box
<A
>>,
86 impl<'a
, A
: ?Sized
+ UncheckedAnyExt
> Iterator
for Iter
<'a
, A
> {
88 #[inline] fn next(&mut self) -> Option<&'a A> { self.inner.next().map(|x| &**x.1) }
89 #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
91 impl<'a
, A
: ?Sized
+ UncheckedAnyExt
> ExactSizeIterator
for Iter
<'a
, A
> {
92 #[inline] fn len(&self) -> usize { self.inner.len() }
95 /// `RawMap` mutable iterator.
96 pub struct IterMut
<'a
, A
: ?Sized
+ UncheckedAnyExt
> {
97 inner
: hash_map
::IterMut
<'a
, TypeId
, Box
<A
>>,
99 impl<'a
, A
: ?Sized
+ UncheckedAnyExt
> Iterator
for IterMut
<'a
, A
> {
100 type Item
= &'a
mut A
;
101 #[inline] fn next(&mut self) -> Option<&'a mut A> { self.inner.next().map(|x| &mut **x.1) }
102 #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
104 impl<'a
, A
: ?Sized
+ UncheckedAnyExt
> ExactSizeIterator
for IterMut
<'a
, A
> {
105 #[inline] fn len(&self) -> usize { self.inner.len() }
108 /// `RawMap` move iterator.
109 pub struct IntoIter
<A
: ?Sized
+ UncheckedAnyExt
> {
110 inner
: hash_map
::IntoIter
<TypeId
, Box
<A
>>,
112 impl<A
: ?Sized
+ UncheckedAnyExt
> Iterator
for IntoIter
<A
> {
114 #[inline] fn next(&mut self) -> Option<Box<A>> { self.inner.next().map(|x| x.1) }
115 #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
117 impl<A
: ?Sized
+ UncheckedAnyExt
> ExactSizeIterator
for IntoIter
<A
> {
118 #[inline] fn len(&self) -> usize { self.inner.len() }
121 /// `RawMap` drain iterator.
122 pub struct Drain
<'a
, A
: ?Sized
+ UncheckedAnyExt
> {
123 inner
: hash_map
::Drain
<'a
, TypeId
, Box
<A
>>,
125 impl<'a
, A
: ?Sized
+ UncheckedAnyExt
> Iterator
for Drain
<'a
, A
> {
127 #[inline] fn next(&mut self) -> Option<Box<A>> { self.inner.next().map(|x| x.1) }
128 #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
130 impl<'a
, A
: ?Sized
+ UncheckedAnyExt
> ExactSizeIterator
for Drain
<'a
, A
> {
131 #[inline] fn len(&self) -> usize { self.inner.len() }
134 impl<A
: ?Sized
+ UncheckedAnyExt
> RawMap
<A
> {
135 /// An iterator visiting all entries in arbitrary order.
137 /// Iterator element type is `&Any`.
139 pub fn iter(&self) -> Iter
<A
> {
141 inner
: self.inner
.iter(),
145 /// An iterator visiting all entries in arbitrary order.
147 /// Iterator element type is `&mut Any`.
149 pub fn iter_mut(&mut self) -> IterMut
<A
> {
151 inner
: self.inner
.iter_mut(),
155 /// Clears the map, returning all items as an iterator.
157 /// Iterator element type is `Box<Any>`.
159 /// Keeps the allocated memory for reuse.
161 pub fn drain(&mut self) -> Drain
<A
> {
163 inner
: self.inner
.drain(),
167 /// Gets the entry for the given type in the collection for in-place manipulation.
169 pub fn entry(&mut self, key
: TypeId
) -> Entry
<A
> {
170 match self.inner
.entry(key
) {
171 hash_map
::Entry
::Occupied(e
) => Entry
::Occupied(OccupiedEntry
{
174 hash_map
::Entry
::Vacant(e
) => Entry
::Vacant(VacantEntry
{
180 /// Returns a reference to the value corresponding to the key.
182 /// The key may be any borrowed form of the map's key type, but `Hash` and `Eq` on the borrowed
183 /// form *must* match those for the key type.
185 pub fn get
<Q
: ?Sized
>(&self, k
: &Q
) -> Option
<&A
>
186 where TypeId
: Borrow
<Q
>, Q
: Hash
+ Eq
{
187 self.inner
.get(k
).map(|x
| &**x
)
190 /// Returns true if the map contains a value for the specified key.
192 /// The key may be any borrowed form of the map's key type, but `Hash` and `Eq` on the borrowed
193 /// form *must* match those for the key type.
195 pub fn contains_key
<Q
: ?Sized
>(&self, k
: &Q
) -> bool
196 where TypeId
: Borrow
<Q
>, Q
: Hash
+ Eq
{
197 self.inner
.contains_key(k
)
200 /// Returns a mutable reference to the value corresponding to the key.
202 /// The key may be any borrowed form of the map's key type, but `Hash` and `Eq` on the borrowed
203 /// form *must* match those for the key type.
205 pub fn get_mut
<Q
: ?Sized
>(&mut self, k
: &Q
) -> Option
<&mut A
>
206 where TypeId
: Borrow
<Q
>, Q
: Hash
+ Eq
{
207 self.inner
.get_mut(k
).map(|x
| &mut **x
)
210 /// Inserts a key-value pair from the map. If the key already had a value present in the map,
211 /// that value is returned. Otherwise, None is returned.
213 /// It is the caller’s responsibility to ensure that the key corresponds with the type ID of
214 /// the value. If they do not, memory safety may be violated.
216 pub unsafe fn insert(&mut self, key
: TypeId
, value
: Box
<A
>) -> Option
<Box
<A
>> {
217 self.inner
.insert(key
, value
)
220 /// Removes a key from the map, returning the value at the key if the key was previously in the
223 /// The key may be any borrowed form of the map's key type, but `Hash` and `Eq` on the borrowed
224 /// form *must* match those for the key type.
226 pub fn remove
<Q
: ?Sized
>(&mut self, k
: &Q
) -> Option
<Box
<A
>>
227 where TypeId
: Borrow
<Q
>, Q
: Hash
+ Eq
{
233 impl<A
: ?Sized
+ UncheckedAnyExt
, Q
> Index
<Q
> for RawMap
<A
> where TypeId
: Borrow
<Q
>, Q
: Eq
+ Hash
{
237 fn index(&self, index
: Q
) -> &A
{
238 self.get(&index
).expect("no entry found for key")
242 impl<A
: ?Sized
+ UncheckedAnyExt
, Q
> IndexMut
<Q
> for RawMap
<A
> where TypeId
: Borrow
<Q
>, Q
: Eq
+ Hash
{
244 fn index_mut(&mut self, index
: Q
) -> &mut A
{
245 self.get_mut(&index
).expect("no entry found for key")
249 impl<A
: ?Sized
+ UncheckedAnyExt
> IntoIterator
for RawMap
<A
> {
251 type IntoIter
= IntoIter
<A
>;
254 fn into_iter(self) -> IntoIter
<A
> {
256 inner
: self.inner
.into_iter(),
261 /// A view into a single occupied location in a `RawMap`.
262 pub struct OccupiedEntry
<'a
, A
: ?Sized
+ UncheckedAnyExt
> {
263 inner
: hash_map
::OccupiedEntry
<'a
, TypeId
, Box
<A
>>,
266 /// A view into a single empty location in a `RawMap`.
267 pub struct VacantEntry
<'a
, A
: ?Sized
+ UncheckedAnyExt
> {
268 inner
: hash_map
::VacantEntry
<'a
, TypeId
, Box
<A
>>,
271 /// A view into a single location in a `RawMap`, which may be vacant or occupied.
272 pub enum Entry
<'a
, A
: ?Sized
+ UncheckedAnyExt
> {
273 /// An occupied Entry
274 Occupied(OccupiedEntry
<'a
, A
>),
276 Vacant(VacantEntry
<'a
, A
>),
279 impl<'a
, A
: ?Sized
+ UncheckedAnyExt
> Entry
<'a
, A
> {
280 /// Ensures a value is in the entry by inserting the default if empty, and returns
281 /// a mutable reference to the value in the entry.
283 /// It is the caller’s responsibility to ensure that the key of the entry corresponds with
284 /// the type ID of `value`. If they do not, memory safety may be violated.
286 pub unsafe fn or_insert(self, default: Box
<A
>) -> &'a
mut A
{
288 Entry
::Occupied(inner
) => inner
.into_mut(),
289 Entry
::Vacant(inner
) => inner
.insert(default),
293 /// Ensures a value is in the entry by inserting the result of the default function if empty,
294 /// and returns a mutable reference to the value in the entry.
296 /// It is the caller’s responsibility to ensure that the key of the entry corresponds with
297 /// the type ID of `value`. If they do not, memory safety may be violated.
299 pub unsafe fn or_insert_with
<F
: FnOnce() -> Box
<A
>>(self, default: F
) -> &'a
mut A
{
301 Entry
::Occupied(inner
) => inner
.into_mut(),
302 Entry
::Vacant(inner
) => inner
.insert(default()),
307 impl<'a
, A
: ?Sized
+ UncheckedAnyExt
> OccupiedEntry
<'a
, A
> {
308 /// Gets a reference to the value in the entry.
310 pub fn get(&self) -> &A
{
314 /// Gets a mutable reference to the value in the entry.
316 pub fn get_mut(&mut self) -> &mut A
{
317 &mut **self.inner
.get_mut()
320 /// Converts the OccupiedEntry into a mutable reference to the value in the entry
321 /// with a lifetime bound to the collection itself.
323 pub fn into_mut(self) -> &'a
mut A
{
324 &mut **self.inner
.into_mut()
327 /// Sets the value of the entry, and returns the entry's old value.
329 /// It is the caller’s responsibility to ensure that the key of the entry corresponds with
330 /// the type ID of `value`. If they do not, memory safety may be violated.
332 pub unsafe fn insert(&mut self, value
: Box
<A
>) -> Box
<A
> {
333 self.inner
.insert(value
)
336 /// Takes the value out of the entry, and returns it.
338 pub fn remove(self) -> Box
<A
> {
343 impl<'a
, A
: ?Sized
+ UncheckedAnyExt
> VacantEntry
<'a
, A
> {
344 /// Sets the value of the entry with the VacantEntry's key,
345 /// and returns a mutable reference to it
347 /// It is the caller’s responsibility to ensure that the key of the entry corresponds with
348 /// the type ID of `value`. If they do not, memory safety may be violated.
350 pub unsafe fn insert(self, value
: Box
<A
>) -> &'a
mut A
{
351 &mut **self.inner
.insert(value
)