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