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 #[cfg(feature = "clone")]
  89 mod with_clone;
  90
  91 /// A collection containing zero or one values for any given type and allowing convenient,
  92 /// type-safe access to those values.
  93 ///
  94 /// ```rust
  95 /// # use anymap::AnyMap;
  96 /// let mut data = AnyMap::new();
  97 /// assert_eq!(data.get(), None::<&i32>);
  98 /// data.insert(42i32);
  99 /// assert_eq!(data.get(), Some(&42i32));
 100 /// data.remove::<i32>();
 101 /// assert_eq!(data.get::<i32>(), None);
 102 ///
 103 /// #[derive(Clone, PartialEq, Debug)]
 104 /// struct Foo {
 105 ///     str: String,
 106 /// }
 107 ///
 108 /// assert_eq!(data.get::<Foo>(), None);
 109 /// data.insert(Foo { str: format!("foo") });
 110 /// assert_eq!(data.get(), Some(&Foo { str: format!("foo") }));
 111 /// data.get_mut::<Foo>().map(|foo| foo.str.push('t'));
 112 /// assert_eq!(&*data.get::<Foo>().unwrap().str, "foot");
 113 /// ```
 114 ///
 115 /// Values containing non-static references are not permitted.
 116 #[derive(Debug)]
 117 #[cfg_attr(feature = "clone", derive(Clone))]
 118 pub struct AnyMap {
 119     raw: RawAnyMap,
 120 }
 121
 122 impl_common_methods! {
 123     field: AnyMap.raw;
 124     new() => RawAnyMap::new();
 125     with_capacity(capacity) => RawAnyMap::with_capacity(capacity);
 126 }
 127
 128 impl AnyMap {
 129     /// Returns a reference to the value stored in the collection for the type `T`, if it exists.
 130     pub fn get<T: Any>(&self) -> Option<&T> {
 131         self.raw.get(&TypeId::of::<T>())
 132             .map(|any| unsafe { any.downcast_ref_unchecked::<T>() })
 133     }
 134
 135     /// Returns a mutable reference to the value stored in the collection for the type `T`,
 136     /// if it exists.
 137     pub fn get_mut<T: Any>(&mut self) -> Option<&mut T> {
 138         self.raw.get_mut(&TypeId::of::<T>())
 139             .map(|any| unsafe { any.downcast_mut_unchecked::<T>() })
 140     }
 141
 142     /// Sets the value stored in the collection for the type `T`.
 143     /// If the collection already had a value of type `T`, that value is returned.
 144     /// Otherwise, `None` is returned.
 145     pub fn insert<T: Any>(&mut self, value: T) -> Option<T> {
 146         unsafe {
 147             self.raw.insert(TypeId::of::<T>(), Box::new(value))
 148                 .map(|any| *any.downcast_unchecked::<T>())
 149         }
 150     }
 151
 152     /// Removes the `T` value from the collection,
 153     /// returning it if there was one or `None` if there was not.
 154     pub fn remove<T: Any>(&mut self) -> Option<T> {
 155         self.raw.remove(&TypeId::of::<T>())
 156             .map(|any| *unsafe { any.downcast_unchecked::<T>() })
 157     }
 158
 159     /// Returns true if the collection contains a value of type `T`.
 160     #[inline]
 161     pub fn contains<T: Any>(&self) -> bool {
 162         self.raw.contains_key(&TypeId::of::<T>())
 163     }
 164
 165     /// Gets the entry for the given type in the collection for in-place manipulation
 166     pub fn entry<T: Any>(&mut self) -> Entry<T> {
 167         match self.raw.entry(TypeId::of::<T>()) {
 168             raw::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry {
 169                 inner: e,
 170                 type_: PhantomData,
 171             }),
 172             raw::Entry::Vacant(e) => Entry::Vacant(VacantEntry {
 173                 inner: e,
 174                 type_: PhantomData,
 175             }),
 176         }
 177     }
 178 }
 179
 180 impl AsRef<RawAnyMap> for AnyMap {
 181     fn as_ref(&self) -> &RawAnyMap {
 182         &self.raw
 183     }
 184 }
 185
 186 impl AsMut<RawAnyMap> for AnyMap {
 187     fn as_mut(&mut self) -> &mut RawAnyMap {
 188         &mut self.raw
 189     }
 190 }
 191
 192 impl Into<RawAnyMap> for AnyMap {
 193     fn into(self) -> RawAnyMap {
 194         self.raw
 195     }
 196 }
 197
 198 /// A view into a single occupied location in an `AnyMap`.
 199 pub struct OccupiedEntry<'a, V: 'a> {
 200     inner: raw::OccupiedEntry<'a>,
 201     type_: PhantomData<V>,
 202 }
 203
 204 /// A view into a single empty location in an `AnyMap`.
 205 pub struct VacantEntry<'a, V: 'a> {
 206     inner: raw::VacantEntry<'a>,
 207     type_: PhantomData<V>,
 208 }
 209
 210 /// A view into a single location in an `AnyMap`, which may be vacant or occupied.
 211 pub enum Entry<'a, V: 'a> {
 212     /// An occupied Entry
 213     Occupied(OccupiedEntry<'a, V>),
 214     /// A vacant Entry
 215     Vacant(VacantEntry<'a, V>),
 216 }
 217
 218 impl<'a, V: Any + Clone> Entry<'a, V> {
 219     /// Ensures a value is in the entry by inserting the default if empty, and returns
 220     /// a mutable reference to the value in the entry.
 221     pub fn or_insert(self, default: V) -> &'a mut V {
 222         match self {
 223             Entry::Occupied(inner) => inner.into_mut(),
 224             Entry::Vacant(inner) => inner.insert(default),
 225         }
 226     }
 227
 228     /// Ensures a value is in the entry by inserting the result of the default function if empty,
 229     /// and returns a mutable reference to the value in the entry.
 230     pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V {
 231         match self {
 232             Entry::Occupied(inner) => inner.into_mut(),
 233             Entry::Vacant(inner) => inner.insert(default()),
 234         }
 235     }
 236 }
 237
 238 impl<'a, V: Any> OccupiedEntry<'a, V> {
 239     /// Gets a reference to the value in the entry
 240     pub fn get(&self) -> &V {
 241         unsafe { self.inner.get().downcast_ref_unchecked() }
 242     }
 243
 244     /// Gets a mutable reference to the value in the entry
 245     pub fn get_mut(&mut self) -> &mut V {
 246         unsafe { self.inner.get_mut().downcast_mut_unchecked() }
 247     }
 248
 249     /// Converts the OccupiedEntry into a mutable reference to the value in the entry
 250     /// with a lifetime bound to the collection itself
 251     pub fn into_mut(self) -> &'a mut V {
 252         unsafe { self.inner.into_mut().downcast_mut_unchecked() }
 253     }
 254
 255     /// Sets the value of the entry, and returns the entry's old value
 256     pub fn insert(&mut self, value: V) -> V {
 257         unsafe { *self.inner.insert(Box::new(value)).downcast_unchecked() }
 258     }
 259
 260     /// Takes the value out of the entry, and returns it
 261     pub fn remove(self) -> V {
 262         unsafe { *self.inner.remove().downcast_unchecked() }
 263     }
 264 }
 265
 266 impl<'a, V: Any> VacantEntry<'a, V> {
 267     /// Sets the value of the entry with the VacantEntry's key,
 268     /// and returns a mutable reference to it
 269     pub fn insert(self, value: V) -> &'a mut V {
 270         unsafe { self.inner.insert(Box::new(value)).downcast_mut_unchecked() }
 271     }
 272 }
 273
 274 #[bench]
 275 fn bench_insertion(b: &mut ::test::Bencher) {
 276     b.iter(|| {
 277         let mut data = AnyMap::new();
 278         for _ in 0..100 {
 279             let _ = data.insert(42);
 280         }
 281     })
 282 }
 283
 284 #[bench]
 285 fn bench_get_missing(b: &mut ::test::Bencher) {
 286     b.iter(|| {
 287         let data = AnyMap::new();
 288         for _ in 0..100 {
 289             assert_eq!(data.get(), None::<&i32>);
 290         }
 291     })
 292 }
 293
 294 #[bench]
 295 fn bench_get_present(b: &mut ::test::Bencher) {
 296     b.iter(|| {
 297         let mut data = AnyMap::new();
 298         let _ = data.insert(42);
 299         // These inner loops are a feeble attempt to drown the other factors.
 300         for _ in 0..100 {
 301             assert_eq!(data.get(), Some(&42));
 302         }
 303     })
 304 }
 305
 306 #[cfg(test)]
 307 mod tests {
 308     use {AnyMap, Entry};
 309
 310     #[derive(Clone, Debug, PartialEq)] struct A(i32);
 311     #[derive(Clone, Debug, PartialEq)] struct B(i32);
 312     #[derive(Clone, Debug, PartialEq)] struct C(i32);
 313     #[derive(Clone, Debug, PartialEq)] struct D(i32);
 314     #[derive(Clone, Debug, PartialEq)] struct E(i32);
 315     #[derive(Clone, Debug, PartialEq)] struct F(i32);
 316     #[derive(Clone, Debug, PartialEq)] struct J(i32);
 317
 318     #[test]
 319     fn test_entry() {
 320         let mut map: AnyMap = AnyMap::new();
 321         assert_eq!(map.insert(A(10)), None);
 322         assert_eq!(map.insert(B(20)), None);
 323         assert_eq!(map.insert(C(30)), None);
 324         assert_eq!(map.insert(D(40)), None);
 325         assert_eq!(map.insert(E(50)), None);
 326         assert_eq!(map.insert(F(60)), None);
 327
 328         // Existing key (insert)
 329         match map.entry::<A>() {
 330             Entry::Vacant(_) => unreachable!(),
 331             Entry::Occupied(mut view) => {
 332                 assert_eq!(view.get(), &A(10));
 333                 assert_eq!(view.insert(A(100)), A(10));
 334             }
 335         }
 336         assert_eq!(map.get::<A>().unwrap(), &A(100));
 337         assert_eq!(map.len(), 6);
 338
 339
 340         // Existing key (update)
 341         match map.entry::<B>() {
 342             Entry::Vacant(_) => unreachable!(),
 343             Entry::Occupied(mut view) => {
 344                 let v = view.get_mut();
 345                 let new_v = B(v.0 * 10);
 346                 *v = new_v;
 347             }
 348         }
 349         assert_eq!(map.get::<B>().unwrap(), &B(200));
 350         assert_eq!(map.len(), 6);
 351
 352
 353         // Existing key (remove)
 354         match map.entry::<C>() {
 355             Entry::Vacant(_) => unreachable!(),
 356             Entry::Occupied(view) => {
 357                 assert_eq!(view.remove(), C(30));
 358             }
 359         }
 360         assert_eq!(map.get::<C>(), None);
 361         assert_eq!(map.len(), 5);
 362
 363
 364         // Inexistent key (insert)
 365         match map.entry::<J>() {
 366             Entry::Occupied(_) => unreachable!(),
 367             Entry::Vacant(view) => {
 368                 assert_eq!(*view.insert(J(1000)), J(1000));
 369             }
 370         }
 371         assert_eq!(map.get::<J>().unwrap(), &J(1000));
 372         assert_eq!(map.len(), 6);
 373
 374         // Entry.or_insert on existing key
 375         map.entry::<B>().or_insert(B(71)).0 += 1;
 376         assert_eq!(map.get::<B>().unwrap(), &B(201));
 377         assert_eq!(map.len(), 6);
 378
 379         // Entry.or_insert on nonexisting key
 380         map.entry::<C>().or_insert(C(300)).0 += 1;
 381         assert_eq!(map.get::<C>().unwrap(), &C(301));
 382         assert_eq!(map.len(), 7);
 383     }
 384
 385     #[cfg(feature = "clone")]
 386     #[test]
 387     fn test_clone() {
 388         let mut map = AnyMap::new();
 389         let _ = map.insert(A(1));
 390         let _ = map.insert(B(2));
 391         let _ = map.insert(D(3));
 392         let _ = map.insert(E(4));
 393         let _ = map.insert(F(5));
 394         let _ = map.insert(J(6));
 395         let map2 = map.clone();
 396         assert_eq!(map2.len(), 6);
 397         assert_eq!(map2.get::<A>(), Some(&A(1)));
 398         assert_eq!(map2.get::<B>(), Some(&B(2)));
 399         assert_eq!(map2.get::<C>(), None);
 400         assert_eq!(map2.get::<D>(), Some(&D(3)));
 401         assert_eq!(map2.get::<E>(), Some(&E(4)));
 402         assert_eq!(map2.get::<F>(), Some(&F(5)));
 403         assert_eq!(map2.get::<J>(), Some(&J(6)));
 404     }
 405 }