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 = "nightly", 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::{RawAnyMap, Any};
  14 use unchecked_any::UncheckedAnyExt;
  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 $t {
  23             /// Create an empty collection.
  24             #[inline]
  25             pub fn new() -> $t {
  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 {
  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 mod unchecked_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 /// ```rust
  93 /// # use anymap::AnyMap;
  94 /// let mut data = AnyMap::new();
  95 /// assert_eq!(data.get(), None::<&i32>);
  96 /// data.insert(42i32);
  97 /// assert_eq!(data.get(), Some(&42i32));
  98 /// data.remove::<i32>();
  99 /// assert_eq!(data.get::<i32>(), None);
 100 ///
 101 /// #[derive(Clone, PartialEq, Debug)]
 102 /// struct Foo {
 103 ///     str: String,
 104 /// }
 105 ///
 106 /// assert_eq!(data.get::<Foo>(), None);
 107 /// data.insert(Foo { str: format!("foo") });
 108 /// assert_eq!(data.get(), Some(&Foo { str: format!("foo") }));
 109 /// data.get_mut::<Foo>().map(|foo| foo.str.push('t'));
 110 /// assert_eq!(&*data.get::<Foo>().unwrap().str, "foot");
 111 /// ```
 112 ///
 113 /// Values containing non-static references are not permitted.
 114 #[derive(Debug)]
 115 #[cfg_attr(feature = "clone", derive(Clone))]
 116 pub struct AnyMap {
 117     raw: RawAnyMap,
 118 }
 119
 120 impl_common_methods! {
 121     field: AnyMap.raw;
 122     new() => RawAnyMap::new();
 123     with_capacity(capacity) => RawAnyMap::with_capacity(capacity);
 124 }
 125
 126 impl AnyMap {
 127     /// Returns a reference to the value stored in the collection for the type `T`, if it exists.
 128     pub fn get<T: Any>(&self) -> Option<&T> {
 129         self.raw.get(&TypeId::of::<T>())
 130             .map(|any| unsafe { any.downcast_ref_unchecked::<T>() })
 131     }
 132
 133     /// Returns a mutable reference to the value stored in the collection for the type `T`,
 134     /// if it exists.
 135     pub fn get_mut<T: Any>(&mut self) -> Option<&mut T> {
 136         self.raw.get_mut(&TypeId::of::<T>())
 137             .map(|any| unsafe { any.downcast_mut_unchecked::<T>() })
 138     }
 139
 140     /// Sets the value stored in the collection for the type `T`.
 141     /// If the collection already had a value of type `T`, that value is returned.
 142     /// Otherwise, `None` is returned.
 143     pub fn insert<T: Any>(&mut self, value: T) -> Option<T> {
 144         unsafe {
 145             self.raw.insert(TypeId::of::<T>(), Box::new(value))
 146                 .map(|any| *any.downcast_unchecked::<T>())
 147         }
 148     }
 149
 150     /// Removes the `T` value from the collection,
 151     /// returning it if there was one or `None` if there was not.
 152     pub fn remove<T: Any>(&mut self) -> Option<T> {
 153         self.raw.remove(&TypeId::of::<T>())
 154             .map(|any| *unsafe { any.downcast_unchecked::<T>() })
 155     }
 156
 157     /// Returns true if the collection contains a value of type `T`.
 158     #[inline]
 159     pub fn contains<T: Any>(&self) -> bool {
 160         self.raw.contains_key(&TypeId::of::<T>())
 161     }
 162
 163     /// Gets the entry for the given type in the collection for in-place manipulation
 164     pub fn entry<T: Any>(&mut self) -> Entry<T> {
 165         match self.raw.entry(TypeId::of::<T>()) {
 166             raw::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry {
 167                 inner: e,
 168                 type_: PhantomData,
 169             }),
 170             raw::Entry::Vacant(e) => Entry::Vacant(VacantEntry {
 171                 inner: e,
 172                 type_: PhantomData,
 173             }),
 174         }
 175     }
 176 }
 177
 178 impl AsRef<RawAnyMap> for AnyMap {
 179     fn as_ref(&self) -> &RawAnyMap {
 180         &self.raw
 181     }
 182 }
 183
 184 impl AsMut<RawAnyMap> for AnyMap {
 185     fn as_mut(&mut self) -> &mut RawAnyMap {
 186         &mut self.raw
 187     }
 188 }
 189
 190 impl Into<RawAnyMap> for AnyMap {
 191     fn into(self) -> RawAnyMap {
 192         self.raw
 193     }
 194 }
 195
 196 /// A view into a single occupied location in an `AnyMap`.
 197 pub struct OccupiedEntry<'a, V: 'a> {
 198     inner: raw::OccupiedEntry<'a>,
 199     type_: PhantomData<V>,
 200 }
 201
 202 /// A view into a single empty location in an `AnyMap`.
 203 pub struct VacantEntry<'a, V: 'a> {
 204     inner: raw::VacantEntry<'a>,
 205     type_: PhantomData<V>,
 206 }
 207
 208 /// A view into a single location in an `AnyMap`, which may be vacant or occupied.
 209 pub enum Entry<'a, V: 'a> {
 210     /// An occupied Entry
 211     Occupied(OccupiedEntry<'a, V>),
 212     /// A vacant Entry
 213     Vacant(VacantEntry<'a, V>),
 214 }
 215
 216 impl<'a, V: Any + Clone> Entry<'a, V> {
 217     /// Ensures a value is in the entry by inserting the default if empty, and returns
 218     /// a mutable reference to the value in the entry.
 219     pub fn or_insert(self, default: V) -> &'a mut V {
 220         match self {
 221             Entry::Occupied(inner) => inner.into_mut(),
 222             Entry::Vacant(inner) => inner.insert(default),
 223         }
 224     }
 225
 226     /// Ensures a value is in the entry by inserting the result of the default function if empty,
 227     /// and returns a mutable reference to the value in the entry.
 228     pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V {
 229         match self {
 230             Entry::Occupied(inner) => inner.into_mut(),
 231             Entry::Vacant(inner) => inner.insert(default()),
 232         }
 233     }
 234 }
 235
 236 impl<'a, V: Any> OccupiedEntry<'a, V> {
 237     /// Gets a reference to the value in the entry
 238     pub fn get(&self) -> &V {
 239         unsafe { self.inner.get().downcast_ref_unchecked() }
 240     }
 241
 242     /// Gets a mutable reference to the value in the entry
 243     pub fn get_mut(&mut self) -> &mut V {
 244         unsafe { self.inner.get_mut().downcast_mut_unchecked() }
 245     }
 246
 247     /// Converts the OccupiedEntry into a mutable reference to the value in the entry
 248     /// with a lifetime bound to the collection itself
 249     pub fn into_mut(self) -> &'a mut V {
 250         unsafe { self.inner.into_mut().downcast_mut_unchecked() }
 251     }
 252
 253     /// Sets the value of the entry, and returns the entry's old value
 254     pub fn insert(&mut self, value: V) -> V {
 255         unsafe { *self.inner.insert(Box::new(value)).downcast_unchecked() }
 256     }
 257
 258     /// Takes the value out of the entry, and returns it
 259     pub fn remove(self) -> V {
 260         unsafe { *self.inner.remove().downcast_unchecked() }
 261     }
 262 }
 263
 264 impl<'a, V: Any> VacantEntry<'a, V> {
 265     /// Sets the value of the entry with the VacantEntry's key,
 266     /// and returns a mutable reference to it
 267     pub fn insert(self, value: V) -> &'a mut V {
 268         unsafe { self.inner.insert(Box::new(value)).downcast_mut_unchecked() }
 269     }
 270 }
 271
 272 #[bench]
 273 fn bench_insertion(b: &mut ::test::Bencher) {
 274     b.iter(|| {
 275         let mut data = AnyMap::new();
 276         for _ in 0..100 {
 277             let _ = data.insert(42);
 278         }
 279     })
 280 }
 281
 282 #[bench]
 283 fn bench_get_missing(b: &mut ::test::Bencher) {
 284     b.iter(|| {
 285         let data = AnyMap::new();
 286         for _ in 0..100 {
 287             assert_eq!(data.get(), None::<&i32>);
 288         }
 289     })
 290 }
 291
 292 #[bench]
 293 fn bench_get_present(b: &mut ::test::Bencher) {
 294     b.iter(|| {
 295         let mut data = AnyMap::new();
 296         let _ = data.insert(42);
 297         // These inner loops are a feeble attempt to drown the other factors.
 298         for _ in 0..100 {
 299             assert_eq!(data.get(), Some(&42));
 300         }
 301     })
 302 }
 303
 304 #[cfg(test)]
 305 mod tests {
 306     use {AnyMap, Entry};
 307
 308     #[derive(Clone, Debug, PartialEq)] struct A(i32);
 309     #[derive(Clone, Debug, PartialEq)] struct B(i32);
 310     #[derive(Clone, Debug, PartialEq)] struct C(i32);
 311     #[derive(Clone, Debug, PartialEq)] struct D(i32);
 312     #[derive(Clone, Debug, PartialEq)] struct E(i32);
 313     #[derive(Clone, Debug, PartialEq)] struct F(i32);
 314     #[derive(Clone, Debug, PartialEq)] struct J(i32);
 315
 316     #[test]
 317     fn test_entry() {
 318         let mut map: AnyMap = AnyMap::new();
 319         assert_eq!(map.insert(A(10)), None);
 320         assert_eq!(map.insert(B(20)), None);
 321         assert_eq!(map.insert(C(30)), None);
 322         assert_eq!(map.insert(D(40)), None);
 323         assert_eq!(map.insert(E(50)), None);
 324         assert_eq!(map.insert(F(60)), None);
 325
 326         // Existing key (insert)
 327         match map.entry::<A>() {
 328             Entry::Vacant(_) => unreachable!(),
 329             Entry::Occupied(mut view) => {
 330                 assert_eq!(view.get(), &A(10));
 331                 assert_eq!(view.insert(A(100)), A(10));
 332             }
 333         }
 334         assert_eq!(map.get::<A>().unwrap(), &A(100));
 335         assert_eq!(map.len(), 6);
 336
 337
 338         // Existing key (update)
 339         match map.entry::<B>() {
 340             Entry::Vacant(_) => unreachable!(),
 341             Entry::Occupied(mut view) => {
 342                 let v = view.get_mut();
 343                 let new_v = B(v.0 * 10);
 344                 *v = new_v;
 345             }
 346         }
 347         assert_eq!(map.get::<B>().unwrap(), &B(200));
 348         assert_eq!(map.len(), 6);
 349
 350
 351         // Existing key (remove)
 352         match map.entry::<C>() {
 353             Entry::Vacant(_) => unreachable!(),
 354             Entry::Occupied(view) => {
 355                 assert_eq!(view.remove(), C(30));
 356             }
 357         }
 358         assert_eq!(map.get::<C>(), None);
 359         assert_eq!(map.len(), 5);
 360
 361
 362         // Inexistent key (insert)
 363         match map.entry::<J>() {
 364             Entry::Occupied(_) => unreachable!(),
 365             Entry::Vacant(view) => {
 366                 assert_eq!(*view.insert(J(1000)), J(1000));
 367             }
 368         }
 369         assert_eq!(map.get::<J>().unwrap(), &J(1000));
 370         assert_eq!(map.len(), 6);
 371
 372         // Entry.or_insert on existing key
 373         map.entry::<B>().or_insert(B(71)).0 += 1;
 374         assert_eq!(map.get::<B>().unwrap(), &B(201));
 375         assert_eq!(map.len(), 6);
 376
 377         // Entry.or_insert on nonexisting key
 378         map.entry::<C>().or_insert(C(300)).0 += 1;
 379         assert_eq!(map.get::<C>().unwrap(), &C(301));
 380         assert_eq!(map.len(), 7);
 381     }
 382
 383     #[cfg(feature = "clone")]
 384     #[test]
 385     fn test_clone() {
 386         let mut map = AnyMap::new();
 387         let _ = map.insert(A(1));
 388         let _ = map.insert(B(2));
 389         let _ = map.insert(D(3));
 390         let _ = map.insert(E(4));
 391         let _ = map.insert(F(5));
 392         let _ = map.insert(J(6));
 393         let map2 = map.clone();
 394         assert_eq!(map2.len(), 6);
 395         assert_eq!(map2.get::<A>(), Some(&A(1)));
 396         assert_eq!(map2.get::<B>(), Some(&B(2)));
 397         assert_eq!(map2.get::<C>(), None);
 398         assert_eq!(map2.get::<D>(), Some(&D(3)));
 399         assert_eq!(map2.get::<E>(), Some(&E(4)));
 400         assert_eq!(map2.get::<F>(), Some(&F(5)));
 401         assert_eq!(map2.get::<J>(), Some(&J(6)));
 402     }
 403
 404     #[cfg(feature = "concurrent")]
 405     #[test]
 406     fn test_concurrent() {
 407         fn assert_concurrent<T: Send + Sync>() { }
 408         assert_concurrent::<AnyMap>();
 409     }
 410 }