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
//! The raw form of a `Map`, allowing untyped access.
//!
//! All relevant details are in the `RawMap` struct.
#[cfg(test)]
use std::mem;
use std::{
any::TypeId,
borrow::Borrow,
collections::hash_map::{self, HashMap},
hash::{BuildHasherDefault, Hash, Hasher},
ops::{Index, IndexMut},
};
use crate::any::{Any, UncheckedAnyExt};
#[derive(Default)]
struct TypeIdHasher {
value: u64,
}
impl Hasher for TypeIdHasher {
#[inline]
fn write(&mut self, bytes: &[u8]) {
// This expects to receive one and exactly one 64-bit value
assert!(bytes.len() == 8);
self.value = u64::from(bytes[0])
| u64::from(bytes[1]) << 8
| u64::from(bytes[2]) << 16
| u64::from(bytes[3]) << 24
| u64::from(bytes[4]) << 32
| u64::from(bytes[5]) << 40
| u64::from(bytes[6]) << 48
| u64::from(bytes[7]) << 56;
}
#[inline]
fn finish(&self) -> u64 {
self.value
}
}
#[test]
fn type_id_hasher() {
fn verify_hashing_with(type_id: TypeId) {
let mut hasher = TypeIdHasher::default();
type_id.hash(&mut hasher);
assert_eq!(hasher.finish(), unsafe {
mem::transmute::<TypeId, u64>(type_id)
});
}
// Pick a variety of types, just to demonstrate it’s all sane. Normal,
// zero-sized, unsized, &c.
verify_hashing_with(TypeId::of::<usize>());
verify_hashing_with(TypeId::of::<()>());
verify_hashing_with(TypeId::of::<str>());
verify_hashing_with(TypeId::of::<&str>());
verify_hashing_with(TypeId::of::<Vec<u8>>());
}
/// The raw, underlying form of a `Map`.
///
/// At its essence, this is a wrapper around `HashMap<TypeId, Box<Any>>`, with
/// the portions that would be memory-unsafe removed or marked unsafe. Normal
/// people are expected to use the safe `Map` interface instead, but there is
/// the occasional use for this such as iteration over the contents of an `Map`.
/// However, because you will then be dealing with `Any` trait objects, it
/// doesn’t tend to be so very useful. Still, if you need it, it’s here.
#[derive(Debug)]
pub struct RawMap<A: ?Sized + UncheckedAnyExt = dyn Any> {
inner: HashMap<TypeId, Box<A>, BuildHasherDefault<TypeIdHasher>>,
}
// #[derive(Clone)] would want A to implement Clone, but in reality it’s only
// Box<A> that can.
impl<A: ?Sized + UncheckedAnyExt> Clone for RawMap<A>
where
Box<A>: Clone,
{
#[inline]
fn clone(&self) -> RawMap<A> {
RawMap {
inner: self.inner.clone(),
}
}
}
impl_common_methods! {
field: RawMap.inner;
new() => HashMap::with_hasher(Default::default());
with_capacity(capacity) => HashMap::with_capacity_and_hasher(capacity, Default::default());
}
/// `RawMap` iterator.
#[derive(Clone)]
pub struct Iter<'a, A: ?Sized + UncheckedAnyExt> {
inner: hash_map::Iter<'a, TypeId, Box<A>>,
}
impl<'a, A: ?Sized + UncheckedAnyExt> Iterator for Iter<'a, A> {
type Item = &'a A;
#[inline]
fn next(&mut self) -> Option<&'a A> {
self.inner.next().map(|x| &**x.1)
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.inner.size_hint()
}
}
impl<'a, A: ?Sized + UncheckedAnyExt> ExactSizeIterator for Iter<'a, A> {
#[inline]
fn len(&self) -> usize {
self.inner.len()
}
}
/// `RawMap` mutable iterator.
pub struct IterMut<'a, A: ?Sized + UncheckedAnyExt> {
inner: hash_map::IterMut<'a, TypeId, Box<A>>,
}
impl<'a, A: ?Sized + UncheckedAnyExt> Iterator for IterMut<'a, A> {
type Item = &'a mut A;
#[inline]
fn next(&mut self) -> Option<&'a mut A> {
self.inner.next().map(|x| &mut **x.1)
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.inner.size_hint()
}
}
impl<'a, A: ?Sized + UncheckedAnyExt> ExactSizeIterator for IterMut<'a, A> {
#[inline]
fn len(&self) -> usize {
self.inner.len()
}
}
/// `RawMap` move iterator.
pub struct IntoIter<A: ?Sized + UncheckedAnyExt> {
inner: hash_map::IntoIter<TypeId, Box<A>>,
}
impl<A: ?Sized + UncheckedAnyExt> Iterator for IntoIter<A> {
type Item = Box<A>;
#[inline]
fn next(&mut self) -> Option<Box<A>> {
self.inner.next().map(|x| x.1)
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.inner.size_hint()
}
}
impl<A: ?Sized + UncheckedAnyExt> ExactSizeIterator for IntoIter<A> {
#[inline]
fn len(&self) -> usize {
self.inner.len()
}
}
/// `RawMap` drain iterator.
pub struct Drain<'a, A: ?Sized + UncheckedAnyExt> {
inner: hash_map::Drain<'a, TypeId, Box<A>>,
}
impl<'a, A: ?Sized + UncheckedAnyExt> Iterator for Drain<'a, A> {
type Item = Box<A>;
#[inline]
fn next(&mut self) -> Option<Box<A>> {
self.inner.next().map(|x| x.1)
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.inner.size_hint()
}
}
impl<'a, A: ?Sized + UncheckedAnyExt> ExactSizeIterator for Drain<'a, A> {
#[inline]
fn len(&self) -> usize {
self.inner.len()
}
}
impl<A: ?Sized + UncheckedAnyExt> RawMap<A> {
/// An iterator visiting all entries in arbitrary order.
///
/// Iterator element type is `&Any`.
#[inline]
pub fn iter(&self) -> Iter<A> {
Iter {
inner: self.inner.iter(),
}
}
/// An iterator visiting all entries in arbitrary order.
///
/// Iterator element type is `&mut Any`.
#[inline]
pub fn iter_mut(&mut self) -> IterMut<A> {
IterMut {
inner: self.inner.iter_mut(),
}
}
/// Clears the map, returning all items as an iterator.
///
/// Iterator element type is `Box<Any>`.
///
/// Keeps the allocated memory for reuse.
#[inline]
pub fn drain(&mut self) -> Drain<A> {
Drain {
inner: self.inner.drain(),
}
}
/// Gets the entry for the given type in the collection for in-place
/// manipulation.
#[inline]
pub fn entry(&mut self, key: TypeId) -> Entry<A> {
match self.inner.entry(key) {
hash_map::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry { inner: e }),
hash_map::Entry::Vacant(e) => Entry::Vacant(VacantEntry { inner: e }),
}
}
/// Returns a reference to the value corresponding to the key.
///
/// The key may be any borrowed form of the map's key type, but `Hash` and
/// `Eq` on the borrowed form *must* match those for the key type.
#[inline]
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&A>
where
TypeId: Borrow<Q>,
Q: Hash + Eq,
{
self.inner.get(k).map(|x| &**x)
}
/// Returns true if the map contains a value for the specified key.
///
/// The key may be any borrowed form of the map's key type, but `Hash` and
/// `Eq` on the borrowed form *must* match those for the key type.
#[inline]
pub fn contains_key<Q: ?Sized>(&self, k: &Q) -> bool
where
TypeId: Borrow<Q>,
Q: Hash + Eq,
{
self.inner.contains_key(k)
}
/// Returns a mutable reference to the value corresponding to the key.
///
/// The key may be any borrowed form of the map's key type, but `Hash` and
/// `Eq` on the borrowed form *must* match those for the key type.
#[inline]
pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut A>
where
TypeId: Borrow<Q>,
Q: Hash + Eq,
{
self.inner.get_mut(k).map(|x| &mut **x)
}
/// Inserts a key-value pair from the map. If the key already had a value
/// present in the map, that value is returned. Otherwise, None is
/// returned.
///
/// # Safety
///
/// It is the caller’s responsibility to ensure that the key corresponds
/// with the type ID of the value. If they do not, memory safety may be
/// violated.
#[inline]
pub unsafe fn insert(&mut self, key: TypeId, value: Box<A>) -> Option<Box<A>> {
self.inner.insert(key, value)
}
/// Removes a key from the map, returning the value at the key if the key
/// was previously in the map.
///
/// The key may be any borrowed form of the map's key type, but `Hash` and
/// `Eq` on the borrowed form *must* match those for the key type.
#[inline]
pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<Box<A>>
where
TypeId: Borrow<Q>,
Q: Hash + Eq,
{
self.inner.remove(k)
}
}
impl<A: ?Sized + UncheckedAnyExt, Q> Index<Q> for RawMap<A>
where
TypeId: Borrow<Q>,
Q: Eq + Hash,
{
type Output = A;
#[inline]
fn index(&self, index: Q) -> &A {
self.get(&index).expect("no entry found for key")
}
}
impl<A: ?Sized + UncheckedAnyExt, Q> IndexMut<Q> for RawMap<A>
where
TypeId: Borrow<Q>,
Q: Eq + Hash,
{
#[inline]
fn index_mut(&mut self, index: Q) -> &mut A {
self.get_mut(&index).expect("no entry found for key")
}
}
impl<A: ?Sized + UncheckedAnyExt> IntoIterator for RawMap<A> {
type IntoIter = IntoIter<A>;
type Item = Box<A>;
#[inline]
fn into_iter(self) -> IntoIter<A> {
IntoIter {
inner: self.inner.into_iter(),
}
}
}
/// A view into a single occupied location in a `RawMap`.
pub struct OccupiedEntry<'a, A: ?Sized + UncheckedAnyExt> {
inner: hash_map::OccupiedEntry<'a, TypeId, Box<A>>,
}
/// A view into a single empty location in a `RawMap`.
pub struct VacantEntry<'a, A: ?Sized + UncheckedAnyExt> {
inner: hash_map::VacantEntry<'a, TypeId, Box<A>>,
}
/// A view into a single location in a `RawMap`, which may be vacant or
/// occupied.
pub enum Entry<'a, A: ?Sized + UncheckedAnyExt> {
/// An occupied Entry
Occupied(OccupiedEntry<'a, A>),
/// A vacant Entry
Vacant(VacantEntry<'a, A>),
}
impl<'a, A: ?Sized + UncheckedAnyExt> Entry<'a, A> {
/// Ensures a value is in the entry by inserting the default if empty, and
/// returns a mutable reference to the value in the entry.
///
/// # Safety
///
/// It is the caller’s responsibility to ensure that the key of the entry
/// corresponds with the type ID of `value`. If they do not, memory
/// safety may be violated.
#[inline]
pub unsafe fn or_insert(self, default: Box<A>) -> &'a mut A {
match self {
Entry::Occupied(inner) => inner.into_mut(),
Entry::Vacant(inner) => inner.insert(default),
}
}
/// Ensures a value is in the entry by inserting the result of the default
/// function if empty, and returns a mutable reference to the value in
/// the entry.
///
/// # Safety
///
/// It is the caller’s responsibility to ensure that the key of the entry
/// corresponds with the type ID of `value`. If they do not, memory
/// safety may be violated.
#[inline]
pub unsafe fn or_insert_with<F: FnOnce() -> Box<A>>(self, default: F) -> &'a mut A {
match self {
Entry::Occupied(inner) => inner.into_mut(),
Entry::Vacant(inner) => inner.insert(default()),
}
}
}
impl<'a, A: ?Sized + UncheckedAnyExt> OccupiedEntry<'a, A> {
/// Gets a reference to the value in the entry.
#[inline]
pub fn get(&self) -> &A {
&**self.inner.get()
}
/// Gets a mutable reference to the value in the entry.
#[inline]
pub fn get_mut(&mut self) -> &mut A {
&mut **self.inner.get_mut()
}
/// Converts the OccupiedEntry into a mutable reference to the value in the
/// entry with a lifetime bound to the collection itself.
#[inline]
pub fn into_mut(self) -> &'a mut A {
&mut **self.inner.into_mut()
}
/// Sets the value of the entry, and returns the entry's old value.
///
/// # Safety
///
/// It is the caller’s responsibility to ensure that the key of the entry
/// corresponds with the type ID of `value`. If they do not, memory
/// safety may be violated.
#[inline]
pub unsafe fn insert(&mut self, value: Box<A>) -> Box<A> {
self.inner.insert(value)
}
/// Takes the value out of the entry, and returns it.
#[inline]
pub fn remove(self) -> Box<A> {
self.inner.remove()
}
}
impl<'a, A: ?Sized + UncheckedAnyExt> VacantEntry<'a, A> {
/// Sets the value of the entry with the VacantEntry's key,
/// and returns a mutable reference to it
///
/// # Safety
///
/// It is the caller’s responsibility to ensure that the key of the entry
/// corresponds with the type ID of `value`. If they do not, memory
/// safety may be violated.
#[inline]
pub unsafe fn insert(self, value: Box<A>) -> &'a mut A {
&mut **self.inner.insert(value)
}
}