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