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         impl<A: ?Sized + UncheckedAnyExt> Default for $t<A> {
  80             #[inline]
  81             fn default() -> $t<A> {
  82                 $t::new()
  83             }
  84         }
  85     }
  86 }
  87
  88 pub mod any;
  89 pub mod raw;
  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 /// The type parameter `A` allows you to use a different value type; normally you will want it to
  95 /// be `anymap::any::Any`, but there are other choices:
  96 ///
  97 /// - If you want the entire map to be cloneable, use `CloneAny` instead of `Any`.
  98 /// - You can add on `+ Send` and/or `+ Sync` (e.g. `Map<Any + Send>`) to add those bounds.
  99 ///
 100 /// ```rust
 101 /// # use anymap::AnyMap;
 102 /// let mut data = AnyMap::new();
 103 /// assert_eq!(data.get(), None::<&i32>);
 104 /// data.insert(42i32);
 105 /// assert_eq!(data.get(), Some(&42i32));
 106 /// data.remove::<i32>();
 107 /// assert_eq!(data.get::<i32>(), None);
 108 ///
 109 /// #[derive(Clone, PartialEq, Debug)]
 110 /// struct Foo {
 111 ///     str: String,
 112 /// }
 113 ///
 114 /// assert_eq!(data.get::<Foo>(), None);
 115 /// data.insert(Foo { str: format!("foo") });
 116 /// assert_eq!(data.get(), Some(&Foo { str: format!("foo") }));
 117 /// data.get_mut::<Foo>().map(|foo| foo.str.push('t'));
 118 /// assert_eq!(&*data.get::<Foo>().unwrap().str, "foot");
 119 /// ```
 120 ///
 121 /// Values containing non-static references are not permitted.
 122 #[derive(Debug)]
 123 pub struct Map<A: ?Sized + UncheckedAnyExt = Any> {
 124     raw: RawMap<A>,
 125 }
 126
 127 // #[derive(Clone)] would want A to implement Clone, but in reality it’s only Box<A> that can.
 128 impl<A: ?Sized + UncheckedAnyExt> Clone for Map<A> where Box<A>: Clone {
 129     #[inline]
 130     fn clone(&self) -> Map<A> {
 131         Map {
 132             raw: self.raw.clone(),
 133         }
 134     }
 135 }
 136
 137 /// The most common type of `Map`: just using `Any`.
 138 ///
 139 /// Why is this a separate type alias rather than a default value for `Map<A>`? `Map::new()`
 140 /// doesn’t seem to be happy to infer that it should go with the default value.
 141 /// It’s a bit sad, really. Ah well, I guess this approach will do.
 142 pub type AnyMap = Map<Any>;
 143
 144 impl_common_methods! {
 145     field: Map.raw;
 146     new() => RawMap::new();
 147     with_capacity(capacity) => RawMap::with_capacity(capacity);
 148 }
 149
 150 impl<A: ?Sized + UncheckedAnyExt> Map<A> {
 151     /// Returns a reference to the value stored in the collection for the type `T`, if it exists.
 152     #[inline]
 153     pub fn get<T: IntoBox<A>>(&self) -> Option<&T> {
 154         self.raw.get(&TypeId::of::<T>())
 155             .map(|any| unsafe { any.downcast_ref_unchecked::<T>() })
 156     }
 157
 158     /// Returns a mutable reference to the value stored in the collection for the type `T`,
 159     /// if it exists.
 160     #[inline]
 161     pub fn get_mut<T: IntoBox<A>>(&mut self) -> Option<&mut T> {
 162         self.raw.get_mut(&TypeId::of::<T>())
 163             .map(|any| unsafe { any.downcast_mut_unchecked::<T>() })
 164     }
 165
 166     /// Sets the value stored in the collection for the type `T`.
 167     /// If the collection already had a value of type `T`, that value is returned.
 168     /// Otherwise, `None` is returned.
 169     #[inline]
 170     pub fn insert<T: IntoBox<A>>(&mut self, value: T) -> Option<T> {
 171         unsafe {
 172             self.raw.insert(TypeId::of::<T>(), value.into_box())
 173                 .map(|any| *any.downcast_unchecked::<T>())
 174         }
 175     }
 176
 177     /// Removes the `T` value from the collection,
 178     /// returning it if there was one or `None` if there was not.
 179     #[inline]
 180     pub fn remove<T: IntoBox<A>>(&mut self) -> Option<T> {
 181         self.raw.remove(&TypeId::of::<T>())
 182             .map(|any| *unsafe { any.downcast_unchecked::<T>() })
 183     }
 184
 185     /// Returns true if the collection contains a value of type `T`.
 186     #[inline]
 187     pub fn contains<T: IntoBox<A>>(&self) -> bool {
 188         self.raw.contains_key(&TypeId::of::<T>())
 189     }
 190
 191     /// Gets the entry for the given type in the collection for in-place manipulation
 192     #[inline]
 193     pub fn entry<T: IntoBox<A>>(&mut self) -> Entry<A, T> {
 194         match self.raw.entry(TypeId::of::<T>()) {
 195             raw::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry {
 196                 inner: e,
 197                 type_: PhantomData,
 198             }),
 199             raw::Entry::Vacant(e) => Entry::Vacant(VacantEntry {
 200                 inner: e,
 201                 type_: PhantomData,
 202             }),
 203         }
 204     }
 205 }
 206
 207 impl<A: ?Sized + UncheckedAnyExt> AsRef<RawMap<A>> for Map<A> {
 208     #[inline]
 209     fn as_ref(&self) -> &RawMap<A> {
 210         &self.raw
 211     }
 212 }
 213
 214 impl<A: ?Sized + UncheckedAnyExt> AsMut<RawMap<A>> for Map<A> {
 215     #[inline]
 216     fn as_mut(&mut self) -> &mut RawMap<A> {
 217         &mut self.raw
 218     }
 219 }
 220
 221 impl<A: ?Sized + UncheckedAnyExt> Into<RawMap<A>> for Map<A> {
 222     #[inline]
 223     fn into(self) -> RawMap<A> {
 224         self.raw
 225     }
 226 }
 227
 228 /// A view into a single occupied location in an `Map`.
 229 pub struct OccupiedEntry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
 230     inner: raw::OccupiedEntry<'a, A>,
 231     type_: PhantomData<V>,
 232 }
 233
 234 /// A view into a single empty location in an `Map`.
 235 pub struct VacantEntry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
 236     inner: raw::VacantEntry<'a, A>,
 237     type_: PhantomData<V>,
 238 }
 239
 240 /// A view into a single location in an `Map`, which may be vacant or occupied.
 241 pub enum Entry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
 242     /// An occupied Entry
 243     Occupied(OccupiedEntry<'a, A, V>),
 244     /// A vacant Entry
 245     Vacant(VacantEntry<'a, A, V>),
 246 }
 247
 248 impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> Entry<'a, A, V> {
 249     /// Ensures a value is in the entry by inserting the default if empty, and returns
 250     /// a mutable reference to the value in the entry.
 251     #[inline]
 252     pub fn or_insert(self, default: V) -> &'a mut V {
 253         match self {
 254             Entry::Occupied(inner) => inner.into_mut(),
 255             Entry::Vacant(inner) => inner.insert(default),
 256         }
 257     }
 258
 259     /// Ensures a value is in the entry by inserting the result of the default function if empty,
 260     /// and returns a mutable reference to the value in the entry.
 261     #[inline]
 262     pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V {
 263         match self {
 264             Entry::Occupied(inner) => inner.into_mut(),
 265             Entry::Vacant(inner) => inner.insert(default()),
 266         }
 267     }
 268 }
 269
 270 impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> OccupiedEntry<'a, A, V> {
 271     /// Gets a reference to the value in the entry
 272     #[inline]
 273     pub fn get(&self) -> &V {
 274         unsafe { self.inner.get().downcast_ref_unchecked() }
 275     }
 276
 277     /// Gets a mutable reference to the value in the entry
 278     #[inline]
 279     pub fn get_mut(&mut self) -> &mut V {
 280         unsafe { self.inner.get_mut().downcast_mut_unchecked() }
 281     }
 282
 283     /// Converts the OccupiedEntry into a mutable reference to the value in the entry
 284     /// with a lifetime bound to the collection itself
 285     #[inline]
 286     pub fn into_mut(self) -> &'a mut V {
 287         unsafe { self.inner.into_mut().downcast_mut_unchecked() }
 288     }
 289
 290     /// Sets the value of the entry, and returns the entry's old value
 291     #[inline]
 292     pub fn insert(&mut self, value: V) -> V {
 293         unsafe { *self.inner.insert(value.into_box()).downcast_unchecked() }
 294     }
 295
 296     /// Takes the value out of the entry, and returns it
 297     #[inline]
 298     pub fn remove(self) -> V {
 299         unsafe { *self.inner.remove().downcast_unchecked() }
 300     }
 301 }
 302
 303 impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> VacantEntry<'a, A, V> {
 304     /// Sets the value of the entry with the VacantEntry's key,
 305     /// and returns a mutable reference to it
 306     #[inline]
 307     pub fn insert(self, value: V) -> &'a mut V {
 308         unsafe { self.inner.insert(value.into_box()).downcast_mut_unchecked() }
 309     }
 310 }
 311
 312 #[cfg(test)]
 313 mod tests {
 314     use {Map, AnyMap, Entry};
 315     use any::{Any, CloneAny};
 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<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<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 }