src/lib.rs - anymap blob - Chris Morgan’s Git repositories

   1 //! This crate provides the `AnyMap` type, a safe and convenient store for one value of each type.
   2
   3 #![cfg_attr(all(feature = "bench", test), feature(test))]
   4 #![warn(missing_docs, unused_results)]
   5
   6 #[cfg(all(feature = "bench", test))]
   7 extern crate test;
   8
   9 use std::any::TypeId;
  10 use std::marker::PhantomData;
  11
  12 use raw::RawMap;
  13 use any::{UncheckedAnyExt, IntoBox, Any};
  14
  15 macro_rules! impl_common_methods {
  16     (
  17         field: $t:ident.$field:ident;
  18         new() => $new:expr;
  19         with_capacity($with_capacity_arg:ident) => $with_capacity:expr;
  20     ) => {
  21         impl<A: ?Sized + UncheckedAnyExt> $t<A> {
  22             /// Create an empty collection.
  23             #[inline]
  24             pub fn new() -> $t<A> {
  25                 $t {
  26                     $field: $new,
  27                 }
  28             }
  29
  30             /// Creates an empty collection with the given initial capacity.
  31             #[inline]
  32             pub fn with_capacity($with_capacity_arg: usize) -> $t<A> {
  33                 $t {
  34                     $field: $with_capacity,
  35                 }
  36             }
  37
  38             /// Returns the number of elements the collection can hold without reallocating.
  39             #[inline]
  40             pub fn capacity(&self) -> usize {
  41                 self.$field.capacity()
  42             }
  43
  44             /// Reserves capacity for at least `additional` more elements to be inserted
  45             /// in the collection. The collection may reserve more space to avoid
  46             /// frequent reallocations.
  47             ///
  48             /// # Panics
  49             ///
  50             /// Panics if the new allocation size overflows `usize`.
  51             #[inline]
  52             pub fn reserve(&mut self, additional: usize) {
  53                 self.$field.reserve(additional)
  54             }
  55
  56             /// Shrinks the capacity of the collection as much as possible. It will drop
  57             /// down as much as possible while maintaining the internal rules
  58             /// and possibly leaving some space in accordance with the resize policy.
  59             #[inline]
  60             pub fn shrink_to_fit(&mut self) {
  61                 self.$field.shrink_to_fit()
  62             }
  63
  64             /// Returns the number of items in the collection.
  65             #[inline]
  66             pub fn len(&self) -> usize {
  67                 self.$field.len()
  68             }
  69
  70             /// Returns true if there are no items in the collection.
  71             #[inline]
  72             pub fn is_empty(&self) -> bool {
  73                 self.$field.is_empty()
  74             }
  75
  76             /// Removes all items from the collection. Keeps the allocated memory for reuse.
  77             #[inline]
  78             pub fn clear(&mut self) {
  79                 self.$field.clear()
  80             }
  81         }
  82     }
  83 }
  84
  85 pub mod any;
  86 pub mod raw;
  87
  88 /// A collection containing zero or one values for any given type and allowing convenient,
  89 /// type-safe access to those values.
  90 ///
  91 /// The type parameter `A` allows you to use a different value type; normally you will want it to
  92 /// be `anymap::any::Any`, but there are other choices:
  93 ///
  94 /// - If you want the entire map to be cloneable, use `CloneAny` instead of `Any`.
  95 /// - You can add on `+ Send` and/or `+ Sync` (e.g. `Map<Any + Send>`) to add those bounds.
  96 ///
  97 /// ```rust
  98 /// # use anymap::AnyMap;
  99 /// let mut data = AnyMap::new();
 100 /// assert_eq!(data.get(), None::<&i32>);
 101 /// data.insert(42i32);
 102 /// assert_eq!(data.get(), Some(&42i32));
 103 /// data.remove::<i32>();
 104 /// assert_eq!(data.get::<i32>(), None);
 105 ///
 106 /// #[derive(Clone, PartialEq, Debug)]
 107 /// struct Foo {
 108 ///     str: String,
 109 /// }
 110 ///
 111 /// assert_eq!(data.get::<Foo>(), None);
 112 /// data.insert(Foo { str: format!("foo") });
 113 /// assert_eq!(data.get(), Some(&Foo { str: format!("foo") }));
 114 /// data.get_mut::<Foo>().map(|foo| foo.str.push('t'));
 115 /// assert_eq!(&*data.get::<Foo>().unwrap().str, "foot");
 116 /// ```
 117 ///
 118 /// Values containing non-static references are not permitted.
 119 #[derive(Debug)]
 120 pub struct Map<A: ?Sized + UncheckedAnyExt = Any> {
 121     raw: RawMap<A>,
 122 }
 123
 124 // #[derive(Clone)] would want A to implement Clone, but in reality it’s only Box<A> that can.
 125 impl<A: ?Sized + UncheckedAnyExt> Clone for Map<A> where Box<A>: Clone {
 126     fn clone(&self) -> Map<A> {
 127         Map {
 128             raw: self.raw.clone(),
 129         }
 130     }
 131 }
 132
 133 /// The most common type of `Map`: just using `Any`.
 134 ///
 135 /// Why is this a separate type alias rather than a default value for `Map<A>`? `Map::new()`
 136 /// doesn’t seem to be happy to infer that it should go with the default value.
 137 /// It’s a bit sad, really. Ah well, I guess this approach will do.
 138 pub type AnyMap = Map<Any>;
 139
 140 impl_common_methods! {
 141     field: Map.raw;
 142     new() => RawMap::new();
 143     with_capacity(capacity) => RawMap::with_capacity(capacity);
 144 }
 145
 146 impl<A: ?Sized + UncheckedAnyExt> Map<A> {
 147     /// Returns a reference to the value stored in the collection for the type `T`, if it exists.
 148     pub fn get<T: IntoBox<A>>(&self) -> Option<&T> {
 149         self.raw.get(&TypeId::of::<T>())
 150             .map(|any| unsafe { any.downcast_ref_unchecked::<T>() })
 151     }
 152
 153     /// Returns a mutable reference to the value stored in the collection for the type `T`,
 154     /// if it exists.
 155     pub fn get_mut<T: IntoBox<A>>(&mut self) -> Option<&mut T> {
 156         self.raw.get_mut(&TypeId::of::<T>())
 157             .map(|any| unsafe { any.downcast_mut_unchecked::<T>() })
 158     }
 159
 160     /// Sets the value stored in the collection for the type `T`.
 161     /// If the collection already had a value of type `T`, that value is returned.
 162     /// Otherwise, `None` is returned.
 163     pub fn insert<T: IntoBox<A>>(&mut self, value: T) -> Option<T> {
 164         unsafe {
 165             self.raw.insert(TypeId::of::<T>(), value.into_box())
 166                 .map(|any| *any.downcast_unchecked::<T>())
 167         }
 168     }
 169
 170     /// Removes the `T` value from the collection,
 171     /// returning it if there was one or `None` if there was not.
 172     pub fn remove<T: IntoBox<A>>(&mut self) -> Option<T> {
 173         self.raw.remove(&TypeId::of::<T>())
 174             .map(|any| *unsafe { any.downcast_unchecked::<T>() })
 175     }
 176
 177     /// Returns true if the collection contains a value of type `T`.
 178     #[inline]
 179     pub fn contains<T: IntoBox<A>>(&self) -> bool {
 180         self.raw.contains_key(&TypeId::of::<T>())
 181     }
 182
 183     /// Gets the entry for the given type in the collection for in-place manipulation
 184     pub fn entry<T: IntoBox<A>>(&mut self) -> Entry<A, T> {
 185         match self.raw.entry(TypeId::of::<T>()) {
 186             raw::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry {
 187                 inner: e,
 188                 type_: PhantomData,
 189             }),
 190             raw::Entry::Vacant(e) => Entry::Vacant(VacantEntry {
 191                 inner: e,
 192                 type_: PhantomData,
 193             }),
 194         }
 195     }
 196 }
 197
 198 impl<A: ?Sized + UncheckedAnyExt> AsRef<RawMap<A>> for Map<A> {
 199     fn as_ref(&self) -> &RawMap<A> {
 200         &self.raw
 201     }
 202 }
 203
 204 impl<A: ?Sized + UncheckedAnyExt> AsMut<RawMap<A>> for Map<A> {
 205     fn as_mut(&mut self) -> &mut RawMap<A> {
 206         &mut self.raw
 207     }
 208 }
 209
 210 impl<A: ?Sized + UncheckedAnyExt> Into<RawMap<A>> for Map<A> {
 211     fn into(self) -> RawMap<A> {
 212         self.raw
 213     }
 214 }
 215
 216 /// A view into a single occupied location in an `Map`.
 217 pub struct OccupiedEntry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
 218     inner: raw::OccupiedEntry<'a, A>,
 219     type_: PhantomData<V>,
 220 }
 221
 222 /// A view into a single empty location in an `Map`.
 223 pub struct VacantEntry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
 224     inner: raw::VacantEntry<'a, A>,
 225     type_: PhantomData<V>,
 226 }
 227
 228 /// A view into a single location in an `Map`, which may be vacant or occupied.
 229 pub enum Entry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
 230     /// An occupied Entry
 231     Occupied(OccupiedEntry<'a, A, V>),
 232     /// A vacant Entry
 233     Vacant(VacantEntry<'a, A, V>),
 234 }
 235
 236 impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> Entry<'a, A, V> {
 237     /// Ensures a value is in the entry by inserting the default if empty, and returns
 238     /// a mutable reference to the value in the entry.
 239     pub fn or_insert(self, default: V) -> &'a mut V {
 240         match self {
 241             Entry::Occupied(inner) => inner.into_mut(),
 242             Entry::Vacant(inner) => inner.insert(default),
 243         }
 244     }
 245
 246     /// Ensures a value is in the entry by inserting the result of the default function if empty,
 247     /// and returns a mutable reference to the value in the entry.
 248     pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V {
 249         match self {
 250             Entry::Occupied(inner) => inner.into_mut(),
 251             Entry::Vacant(inner) => inner.insert(default()),
 252         }
 253     }
 254 }
 255
 256 impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> OccupiedEntry<'a, A, V> {
 257     /// Gets a reference to the value in the entry
 258     pub fn get(&self) -> &V {
 259         unsafe { self.inner.get().downcast_ref_unchecked() }
 260     }
 261
 262     /// Gets a mutable reference to the value in the entry
 263     pub fn get_mut(&mut self) -> &mut V {
 264         unsafe { self.inner.get_mut().downcast_mut_unchecked() }
 265     }
 266
 267     /// Converts the OccupiedEntry into a mutable reference to the value in the entry
 268     /// with a lifetime bound to the collection itself
 269     pub fn into_mut(self) -> &'a mut V {
 270         unsafe { self.inner.into_mut().downcast_mut_unchecked() }
 271     }
 272
 273     /// Sets the value of the entry, and returns the entry's old value
 274     pub fn insert(&mut self, value: V) -> V {
 275         unsafe { *self.inner.insert(value.into_box()).downcast_unchecked() }
 276     }
 277
 278     /// Takes the value out of the entry, and returns it
 279     pub fn remove(self) -> V {
 280         unsafe { *self.inner.remove().downcast_unchecked() }
 281     }
 282 }
 283
 284 impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> VacantEntry<'a, A, V> {
 285     /// Sets the value of the entry with the VacantEntry's key,
 286     /// and returns a mutable reference to it
 287     pub fn insert(self, value: V) -> &'a mut V {
 288         unsafe { self.inner.insert(value.into_box()).downcast_mut_unchecked() }
 289     }
 290 }
 291
 292 #[cfg(feature = "bench")]
 293 #[bench]
 294 fn bench_insertion(b: &mut ::test::Bencher) {
 295     b.iter(|| {
 296         let mut data = AnyMap::new();
 297         for _ in 0..100 {
 298             let _ = data.insert(42);
 299         }
 300     })
 301 }
 302
 303 #[cfg(feature = "bench")]
 304 #[bench]
 305 fn bench_get_missing(b: &mut ::test::Bencher) {
 306     b.iter(|| {
 307         let data = AnyMap::new();
 308         for _ in 0..100 {
 309             assert_eq!(data.get(), None::<&i32>);
 310         }
 311     })
 312 }
 313
 314 #[cfg(feature = "bench")]
 315 #[bench]
 316 fn bench_get_present(b: &mut ::test::Bencher) {
 317     b.iter(|| {
 318         let mut data = AnyMap::new();
 319         let _ = data.insert(42);
 320         // These inner loops are a feeble attempt to drown the other factors.
 321         for _ in 0..100 {
 322             assert_eq!(data.get(), Some(&42));
 323         }
 324     })
 325 }
 326
 327 #[cfg(test)]
 328 mod tests {
 329     use {Map, AnyMap, Entry};
 330     use any::{Any, CloneAny};
 331
 332     #[derive(Clone, Debug, PartialEq)] struct A(i32);
 333     #[derive(Clone, Debug, PartialEq)] struct B(i32);
 334     #[derive(Clone, Debug, PartialEq)] struct C(i32);
 335     #[derive(Clone, Debug, PartialEq)] struct D(i32);
 336     #[derive(Clone, Debug, PartialEq)] struct E(i32);
 337     #[derive(Clone, Debug, PartialEq)] struct F(i32);
 338     #[derive(Clone, Debug, PartialEq)] struct J(i32);
 339
 340     macro_rules! test_entry {
 341         ($name:ident, $init:ty) => {
 342             #[test]
 343             fn $name() {
 344                 let mut map = <$init>::new();
 345                 assert_eq!(map.insert(A(10)), None);
 346                 assert_eq!(map.insert(B(20)), None);
 347                 assert_eq!(map.insert(C(30)), None);
 348                 assert_eq!(map.insert(D(40)), None);
 349                 assert_eq!(map.insert(E(50)), None);
 350                 assert_eq!(map.insert(F(60)), None);
 351
 352                 // Existing key (insert)
 353                 match map.entry::<A>() {
 354                     Entry::Vacant(_) => unreachable!(),
 355                     Entry::Occupied(mut view) => {
 356                         assert_eq!(view.get(), &A(10));
 357                         assert_eq!(view.insert(A(100)), A(10));
 358                     }
 359                 }
 360                 assert_eq!(map.get::<A>().unwrap(), &A(100));
 361                 assert_eq!(map.len(), 6);
 362
 363
 364                 // Existing key (update)
 365                 match map.entry::<B>() {
 366                     Entry::Vacant(_) => unreachable!(),
 367                     Entry::Occupied(mut view) => {
 368                         let v = view.get_mut();
 369                         let new_v = B(v.0 * 10);
 370                         *v = new_v;
 371                     }
 372                 }
 373                 assert_eq!(map.get::<B>().unwrap(), &B(200));
 374                 assert_eq!(map.len(), 6);
 375
 376
 377                 // Existing key (remove)
 378                 match map.entry::<C>() {
 379                     Entry::Vacant(_) => unreachable!(),
 380                     Entry::Occupied(view) => {
 381                         assert_eq!(view.remove(), C(30));
 382                     }
 383                 }
 384                 assert_eq!(map.get::<C>(), None);
 385                 assert_eq!(map.len(), 5);
 386
 387
 388                 // Inexistent key (insert)
 389                 match map.entry::<J>() {
 390                     Entry::Occupied(_) => unreachable!(),
 391                     Entry::Vacant(view) => {
 392                         assert_eq!(*view.insert(J(1000)), J(1000));
 393                     }
 394                 }
 395                 assert_eq!(map.get::<J>().unwrap(), &J(1000));
 396                 assert_eq!(map.len(), 6);
 397
 398                 // Entry.or_insert on existing key
 399                 map.entry::<B>().or_insert(B(71)).0 += 1;
 400                 assert_eq!(map.get::<B>().unwrap(), &B(201));
 401                 assert_eq!(map.len(), 6);
 402
 403                 // Entry.or_insert on nonexisting key
 404                 map.entry::<C>().or_insert(C(300)).0 += 1;
 405                 assert_eq!(map.get::<C>().unwrap(), &C(301));
 406                 assert_eq!(map.len(), 7);
 407             }
 408         }
 409     }
 410
 411     test_entry!(test_entry_any, AnyMap);
 412     test_entry!(test_entry_cloneany, Map<CloneAny>);
 413
 414     #[test]
 415     fn test_clone() {
 416         let mut map: Map<CloneAny> = Map::new();
 417         let _ = map.insert(A(1));
 418         let _ = map.insert(B(2));
 419         let _ = map.insert(D(3));
 420         let _ = map.insert(E(4));
 421         let _ = map.insert(F(5));
 422         let _ = map.insert(J(6));
 423         let map2 = map.clone();
 424         assert_eq!(map2.len(), 6);
 425         assert_eq!(map2.get::<A>(), Some(&A(1)));
 426         assert_eq!(map2.get::<B>(), Some(&B(2)));
 427         assert_eq!(map2.get::<C>(), None);
 428         assert_eq!(map2.get::<D>(), Some(&D(3)));
 429         assert_eq!(map2.get::<E>(), Some(&E(4)));
 430         assert_eq!(map2.get::<F>(), Some(&F(5)));
 431         assert_eq!(map2.get::<J>(), Some(&J(6)));
 432     }
 433
 434     #[test]
 435     fn test_varieties() {
 436         fn assert_send<T: Send>() { }
 437         fn assert_sync<T: Sync>() { }
 438         fn assert_clone<T: Clone>() { }
 439         fn assert_debug<T: ::std::fmt::Debug>() { }
 440         assert_send::<Map<Any + Send>>();
 441         assert_send::<Map<Any + Send + Sync>>();
 442         assert_sync::<Map<Any + Sync>>();
 443         assert_sync::<Map<Any + Send + Sync>>();
 444         assert_debug::<Map<Any>>();
 445         assert_debug::<Map<Any + Send>>();
 446         assert_debug::<Map<Any + Sync>>();
 447         assert_debug::<Map<Any + Send + Sync>>();
 448         assert_send::<Map<CloneAny + Send>>();
 449         assert_send::<Map<CloneAny + Send + Sync>>();
 450         assert_sync::<Map<CloneAny + Sync>>();
 451         assert_sync::<Map<CloneAny + Send + Sync>>();
 452         assert_clone::<Map<CloneAny + Send>>();
 453         assert_clone::<Map<CloneAny + Send + Sync>>();
 454         assert_clone::<Map<CloneAny + Sync>>();
 455         assert_clone::<Map<CloneAny + Send + Sync>>();
 456         assert_debug::<Map<CloneAny>>();
 457         assert_debug::<Map<CloneAny + Send>>();
 458         assert_debug::<Map<CloneAny + Sync>>();
 459         assert_debug::<Map<CloneAny + Send + Sync>>();
 460     }
 461 }