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