-//! This crate provides the `AnyMap` type, a safe and convenient store for one value of each type.
+//! This crate provides a safe and convenient store for one value of each type.
+//!
+//! Your starting point is [`Map`]. It has an example.
-#![crate_name = "anymap"]
-#![crate_type = "lib"]
-#![feature(default_type_params)]
-#![warn(unused_qualifications, non_upper_case_globals,
- variant_size_differences, unused_typecasts,
- missing_docs, unused_results)]
+#![warn(missing_docs, unused_results)]
-#[cfg(test)]
-extern crate test;
+use core::any::{Any, TypeId};
+use core::marker::PhantomData;
-use std::any::Any;
-use std::intrinsics::TypeId;
-use std::collections::HashMap;
-use std::hash::{Hash, Hasher, Writer};
-use std::mem::{transmute, transmute_copy};
-use std::raw::TraitObject;
+use raw::RawMap;
+use any::{UncheckedAnyExt, IntoBox};
+pub use any::CloneAny;
-struct TypeIdHasher;
+macro_rules! impl_common_methods {
+ (
+ field: $t:ident.$field:ident;
+ new() => $new:expr;
+ with_capacity($with_capacity_arg:ident) => $with_capacity:expr;
+ ) => {
+ impl<A: ?Sized + UncheckedAnyExt> $t<A> {
+ /// Create an empty collection.
+ #[inline]
+ pub fn new() -> $t<A> {
+ $t {
+ $field: $new,
+ }
+ }
-struct TypeIdState {
- value: u64,
-}
+ /// Creates an empty collection with the given initial capacity.
+ #[inline]
+ pub fn with_capacity($with_capacity_arg: usize) -> $t<A> {
+ $t {
+ $field: $with_capacity,
+ }
+ }
-impl Writer for TypeIdState {
- #[inline(always)]
- fn write(&mut self, bytes: &[u8]) {
- // This expects to receive one and exactly one 64-bit value
- debug_assert!(bytes.len() == 8);
- unsafe {
- std::ptr::copy_nonoverlapping_memory(&mut self.value,
- transmute(&bytes[0]),
- 1)
- }
- }
-}
+ /// Returns the number of elements the collection can hold without reallocating.
+ #[inline]
+ pub fn capacity(&self) -> usize {
+ self.$field.capacity()
+ }
-impl Hasher<TypeIdState> for TypeIdHasher {
- fn hash<Sized? T: Hash<TypeIdState>>(&self, value: &T) -> u64 {
- let mut state = TypeIdState {
- value: 0,
- };
- value.hash(&mut state);
- state.value
- }
-}
+ /// Reserves capacity for at least `additional` more elements to be inserted
+ /// in the collection. The collection may reserve more space to avoid
+ /// frequent reallocations.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new allocation size overflows `usize`.
+ #[inline]
+ pub fn reserve(&mut self, additional: usize) {
+ self.$field.reserve(additional)
+ }
-/// An extension of `AnyRefExt` allowing unchecked downcasting of trait objects to `&T`.
-trait UncheckedAnyRefExt<'a> {
- /// Returns a reference to the boxed value, assuming that it is of type `T`. This should only be
- /// called if you are ABSOLUTELY CERTAIN of `T` as you will get really wacky output if it’s not.
- unsafe fn as_ref_unchecked<T: 'static>(self) -> &'a T;
-}
+ /// Shrinks the capacity of the collection as much as possible. It will drop
+ /// down as much as possible while maintaining the internal rules
+ /// and possibly leaving some space in accordance with the resize policy.
+ #[inline]
+ pub fn shrink_to_fit(&mut self) {
+ self.$field.shrink_to_fit()
+ }
-impl<'a> UncheckedAnyRefExt<'a> for &'a Any + 'a {
- #[inline]
- unsafe fn as_ref_unchecked<T: 'static>(self) -> &'a T {
- // Get the raw representation of the trait object
- let to: TraitObject = transmute_copy(&self);
+ /// Returns the number of items in the collection.
+ #[inline]
+ pub fn len(&self) -> usize {
+ self.$field.len()
+ }
- // Extract the data pointer
- transmute(to.data)
- }
-}
+ /// Returns true if there are no items in the collection.
+ #[inline]
+ pub fn is_empty(&self) -> bool {
+ self.$field.is_empty()
+ }
-/// An extension of `AnyMutRefExt` allowing unchecked downcasting of trait objects to `&mut T`.
-trait UncheckedAnyMutRefExt<'a> {
- /// Returns a reference to the boxed value, assuming that it is of type `T`. This should only be
- /// called if you are ABSOLUTELY CERTAIN of `T` as you will get really wacky output if it’s not.
- unsafe fn as_mut_unchecked<T: 'static>(self) -> &'a mut T;
-}
-
-impl<'a> UncheckedAnyMutRefExt<'a> for &'a mut Any + 'a {
- #[inline]
- unsafe fn as_mut_unchecked<T: 'static>(self) -> &'a mut T {
- // Get the raw representation of the trait object
- let to: TraitObject = transmute_copy(&self);
+ /// Removes all items from the collection. Keeps the allocated memory for reuse.
+ #[inline]
+ pub fn clear(&mut self) {
+ self.$field.clear()
+ }
+ }
- // Extract the data pointer
- transmute(to.data)
+ impl<A: ?Sized + UncheckedAnyExt> Default for $t<A> {
+ #[inline]
+ fn default() -> $t<A> {
+ $t::new()
+ }
+ }
}
}
-/// A map containing zero or one values for any given type and allowing convenient,
+mod any;
+pub mod raw;
+
+/// A collection containing zero or one values for any given type and allowing convenient,
/// type-safe access to those values.
///
+/// The type parameter `A` allows you to use a different value type; normally you will want it to
+/// be `core::any::Any` (also known as `std::any::Any`), but there are other choices:
+///
+/// - If you want the entire map to be cloneable, use `CloneAny` instead of `Any`; with that, you
+/// can only add types that implement `Clone` to the map.
+/// - You can add on `+ Send` or `+ Send + Sync` (e.g. `Map<dyn Any + Send>`) to add those auto
+/// traits.
+///
+/// Cumulatively, there are thus six forms of map:
+///
+/// - <code>[Map]<dyn [core::any::Any]></code>, also spelled [`AnyMap`] for convenience.
+/// - <code>[Map]<dyn [core::any::Any] + Send></code>
+/// - <code>[Map]<dyn [core::any::Any] + Send + Sync></code>
+/// - <code>[Map]<dyn [CloneAny]></code>
+/// - <code>[Map]<dyn [CloneAny] + Send></code>
+/// - <code>[Map]<dyn [CloneAny] + Send + Sync></code>
+///
+/// ## Example
+///
+/// (Here using the [`AnyMap`] convenience alias; the first line could use
+/// <code>[anymap::Map][Map]::<[core::any::Any]>::new()</code> instead if desired.)
+///
/// ```rust
-/// # use anymap::AnyMap;
-/// let mut data = AnyMap::new();
-/// assert_eq!(data.find(), None::<&int>);
-/// data.insert(42i);
-/// assert_eq!(data.find(), Some(&42i));
-/// data.remove::<int>();
-/// assert_eq!(data.find::<int>(), None);
+/// let mut data = anymap::AnyMap::new();
+/// assert_eq!(data.get(), None::<&i32>);
+/// data.insert(42i32);
+/// assert_eq!(data.get(), Some(&42i32));
+/// data.remove::<i32>();
+/// assert_eq!(data.get::<i32>(), None);
///
-/// #[deriving(PartialEq, Show)]
+/// #[derive(Clone, PartialEq, Debug)]
/// struct Foo {
/// str: String,
/// }
///
-/// assert_eq!(data.find::<Foo>(), None);
-/// data.insert(Foo { str: "foo".to_string() });
-/// assert_eq!(data.find(), Some(&Foo { str: "foo".to_string() }));
-/// data.find_mut::<Foo>().map(|foo| foo.str.push('t'));
-/// assert_eq!(data.find::<Foo>().unwrap().str.as_slice(), "foot");
+/// assert_eq!(data.get::<Foo>(), None);
+/// data.insert(Foo { str: format!("foo") });
+/// assert_eq!(data.get(), Some(&Foo { str: format!("foo") }));
+/// data.get_mut::<Foo>().map(|foo| foo.str.push('t'));
+/// assert_eq!(&*data.get::<Foo>().unwrap().str, "foot");
/// ```
///
/// Values containing non-static references are not permitted.
-pub struct AnyMap {
- data: HashMap<TypeId, Box<Any + 'static>, TypeIdHasher>,
+#[derive(Debug)]
+pub struct Map<A: ?Sized + UncheckedAnyExt = dyn Any> {
+ raw: RawMap<A>,
}
-impl AnyMap {
- /// Construct a new `AnyMap`.
- pub fn new() -> AnyMap {
- AnyMap {
- data: HashMap::with_hasher(TypeIdHasher),
+// #[derive(Clone)] would want A to implement Clone, but in reality it’s only Box<A> that can.
+impl<A: ?Sized + UncheckedAnyExt> Clone for Map<A> where Box<A>: Clone {
+ #[inline]
+ fn clone(&self) -> Map<A> {
+ Map {
+ raw: self.raw.clone(),
}
}
}
-impl AnyMap {
- /// Retrieve the value stored in the map for the type `T`, if it exists.
- pub fn find<T: Any + 'static>(&self) -> Option<&T> {
- self.data.find(&TypeId::of::<T>()).map(|any| unsafe { any.as_ref_unchecked::<T>() })
+/// The most common type of `Map`: just using `Any`; <code>[Map]<dyn [Any]></code>.
+///
+/// Why is this a separate type alias rather than a default value for `Map<A>`? `Map::new()`
+/// doesn’t seem to be happy to infer that it should go with the default value.
+/// It’s a bit sad, really. Ah well, I guess this approach will do.
+pub type AnyMap = Map<dyn Any>;
+
+impl_common_methods! {
+ field: Map.raw;
+ new() => RawMap::new();
+ with_capacity(capacity) => RawMap::with_capacity(capacity);
+}
+
+impl<A: ?Sized + UncheckedAnyExt> Map<A> {
+ /// Returns a reference to the value stored in the collection for the type `T`, if it exists.
+ #[inline]
+ pub fn get<T: IntoBox<A>>(&self) -> Option<&T> {
+ self.raw.get(&TypeId::of::<T>())
+ .map(|any| unsafe { any.downcast_ref_unchecked::<T>() })
+ }
+
+ /// Returns a mutable reference to the value stored in the collection for the type `T`,
+ /// if it exists.
+ #[inline]
+ pub fn get_mut<T: IntoBox<A>>(&mut self) -> Option<&mut T> {
+ self.raw.get_mut(&TypeId::of::<T>())
+ .map(|any| unsafe { any.downcast_mut_unchecked::<T>() })
}
- /// Retrieve a mutable reference to the value stored in the map for the type `T`, if it exists.
- pub fn find_mut<T: Any + 'static>(&mut self) -> Option<&mut T> {
- self.data.find_mut(&TypeId::of::<T>()).map(|any| unsafe { any.as_mut_unchecked::<T>() })
+ /// Sets the value stored in the collection for the type `T`.
+ /// If the collection already had a value of type `T`, that value is returned.
+ /// Otherwise, `None` is returned.
+ #[inline]
+ pub fn insert<T: IntoBox<A>>(&mut self, value: T) -> Option<T> {
+ unsafe {
+ self.raw.insert(TypeId::of::<T>(), value.into_box())
+ .map(|any| *any.downcast_unchecked::<T>())
+ }
}
- /// Set the value contained in the map for the type `T`.
- /// This will override any previous value stored.
- pub fn insert<T: Any + 'static>(&mut self, value: T) {
- self.data.insert(TypeId::of::<T>(), box value as Box<Any>);
+ /// Removes the `T` value from the collection,
+ /// returning it if there was one or `None` if there was not.
+ #[inline]
+ pub fn remove<T: IntoBox<A>>(&mut self) -> Option<T> {
+ self.raw.remove(&TypeId::of::<T>())
+ .map(|any| *unsafe { any.downcast_unchecked::<T>() })
}
- /// Remove the value for the type `T` if it existed.
- pub fn remove<T: Any + 'static>(&mut self) {
- self.data.remove(&TypeId::of::<T>());
+ /// Returns true if the collection contains a value of type `T`.
+ #[inline]
+ pub fn contains<T: IntoBox<A>>(&self) -> bool {
+ self.raw.contains_key(&TypeId::of::<T>())
}
- /// Does a value of type `T` exist?
- pub fn contains<T: Any + 'static>(&self) -> bool {
- self.data.contains_key(&TypeId::of::<T>())
+ /// Gets the entry for the given type in the collection for in-place manipulation
+ #[inline]
+ pub fn entry<T: IntoBox<A>>(&mut self) -> Entry<A, T> {
+ match self.raw.entry(TypeId::of::<T>()) {
+ raw::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry {
+ inner: e,
+ type_: PhantomData,
+ }),
+ raw::Entry::Vacant(e) => Entry::Vacant(VacantEntry {
+ inner: e,
+ type_: PhantomData,
+ }),
+ }
}
+}
- /// Returns the number of items in the collection.
- pub fn len(&self) -> uint {
- self.data.len()
+impl<A: ?Sized + UncheckedAnyExt> AsRef<RawMap<A>> for Map<A> {
+ #[inline]
+ fn as_ref(&self) -> &RawMap<A> {
+ &self.raw
}
+}
- /// Returns true if there are no items in the collection.
- pub fn is_empty(&self) -> bool {
- self.data.is_empty()
+impl<A: ?Sized + UncheckedAnyExt> AsMut<RawMap<A>> for Map<A> {
+ #[inline]
+ fn as_mut(&mut self) -> &mut RawMap<A> {
+ &mut self.raw
}
+}
- /// Removes all items from the collection.
- pub fn clear(&mut self) {
- self.data.clear();
+impl<A: ?Sized + UncheckedAnyExt> From<Map<A>> for RawMap<A> {
+ #[inline]
+ fn from(map: Map<A>) -> RawMap<A> {
+ map.raw
}
}
-#[bench]
-fn bench_insertion(b: &mut ::test::Bencher) {
- b.iter(|| {
- let mut data = AnyMap::new();
- for _ in range(0u, 100) {
- data.insert(42i);
- }
- })
+/// A view into a single occupied location in an `Map`.
+pub struct OccupiedEntry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
+ inner: raw::OccupiedEntry<'a, A>,
+ type_: PhantomData<V>,
+}
+
+/// A view into a single empty location in an `Map`.
+pub struct VacantEntry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
+ inner: raw::VacantEntry<'a, A>,
+ type_: PhantomData<V>,
}
-#[bench]
-fn bench_find_missing(b: &mut ::test::Bencher) {
- b.iter(|| {
- let data = AnyMap::new();
- for _ in range(0u, 100) {
- assert_eq!(data.find(), None::<&int>);
+/// A view into a single location in an `Map`, which may be vacant or occupied.
+pub enum Entry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
+ /// An occupied Entry
+ Occupied(OccupiedEntry<'a, A, V>),
+ /// A vacant Entry
+ Vacant(VacantEntry<'a, A, V>),
+}
+
+impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> Entry<'a, A, V> {
+ /// Ensures a value is in the entry by inserting the default if empty, and returns
+ /// a mutable reference to the value in the entry.
+ #[inline]
+ pub fn or_insert(self, default: V) -> &'a mut V {
+ match self {
+ Entry::Occupied(inner) => inner.into_mut(),
+ Entry::Vacant(inner) => inner.insert(default),
+ }
+ }
+
+ /// Ensures a value is in the entry by inserting the result of the default function if empty,
+ /// and returns a mutable reference to the value in the entry.
+ #[inline]
+ pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V {
+ match self {
+ Entry::Occupied(inner) => inner.into_mut(),
+ Entry::Vacant(inner) => inner.insert(default()),
}
- })
+ }
+}
+
+impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> OccupiedEntry<'a, A, V> {
+ /// Gets a reference to the value in the entry
+ #[inline]
+ pub fn get(&self) -> &V {
+ unsafe { self.inner.get().downcast_ref_unchecked() }
+ }
+
+ /// Gets a mutable reference to the value in the entry
+ #[inline]
+ pub fn get_mut(&mut self) -> &mut V {
+ unsafe { self.inner.get_mut().downcast_mut_unchecked() }
+ }
+
+ /// Converts the OccupiedEntry into a mutable reference to the value in the entry
+ /// with a lifetime bound to the collection itself
+ #[inline]
+ pub fn into_mut(self) -> &'a mut V {
+ unsafe { self.inner.into_mut().downcast_mut_unchecked() }
+ }
+
+ /// Sets the value of the entry, and returns the entry's old value
+ #[inline]
+ pub fn insert(&mut self, value: V) -> V {
+ unsafe { *self.inner.insert(value.into_box()).downcast_unchecked() }
+ }
+
+ /// Takes the value out of the entry, and returns it
+ #[inline]
+ pub fn remove(self) -> V {
+ unsafe { *self.inner.remove().downcast_unchecked() }
+ }
}
-#[bench]
-fn bench_find_present(b: &mut ::test::Bencher) {
- b.iter(|| {
- let mut data = AnyMap::new();
- data.insert(42i);
- // These inner loops are a feeble attempt to drown the other factors.
- for _ in range(0u, 100) {
- assert_eq!(data.find(), Some(&42i));
+impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> VacantEntry<'a, A, V> {
+ /// Sets the value of the entry with the VacantEntry's key,
+ /// and returns a mutable reference to it
+ #[inline]
+ pub fn insert(self, value: V) -> &'a mut V {
+ unsafe { self.inner.insert(value.into_box()).downcast_mut_unchecked() }
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[derive(Clone, Debug, PartialEq)] struct A(i32);
+ #[derive(Clone, Debug, PartialEq)] struct B(i32);
+ #[derive(Clone, Debug, PartialEq)] struct C(i32);
+ #[derive(Clone, Debug, PartialEq)] struct D(i32);
+ #[derive(Clone, Debug, PartialEq)] struct E(i32);
+ #[derive(Clone, Debug, PartialEq)] struct F(i32);
+ #[derive(Clone, Debug, PartialEq)] struct J(i32);
+
+ macro_rules! test_entry {
+ ($name:ident, $init:ty) => {
+ #[test]
+ fn $name() {
+ let mut map = <$init>::new();
+ assert_eq!(map.insert(A(10)), None);
+ assert_eq!(map.insert(B(20)), None);
+ assert_eq!(map.insert(C(30)), None);
+ assert_eq!(map.insert(D(40)), None);
+ assert_eq!(map.insert(E(50)), None);
+ assert_eq!(map.insert(F(60)), None);
+
+ // Existing key (insert)
+ match map.entry::<A>() {
+ Entry::Vacant(_) => unreachable!(),
+ Entry::Occupied(mut view) => {
+ assert_eq!(view.get(), &A(10));
+ assert_eq!(view.insert(A(100)), A(10));
+ }
+ }
+ assert_eq!(map.get::<A>().unwrap(), &A(100));
+ assert_eq!(map.len(), 6);
+
+
+ // Existing key (update)
+ match map.entry::<B>() {
+ Entry::Vacant(_) => unreachable!(),
+ Entry::Occupied(mut view) => {
+ let v = view.get_mut();
+ let new_v = B(v.0 * 10);
+ *v = new_v;
+ }
+ }
+ assert_eq!(map.get::<B>().unwrap(), &B(200));
+ assert_eq!(map.len(), 6);
+
+
+ // Existing key (remove)
+ match map.entry::<C>() {
+ Entry::Vacant(_) => unreachable!(),
+ Entry::Occupied(view) => {
+ assert_eq!(view.remove(), C(30));
+ }
+ }
+ assert_eq!(map.get::<C>(), None);
+ assert_eq!(map.len(), 5);
+
+
+ // Inexistent key (insert)
+ match map.entry::<J>() {
+ Entry::Occupied(_) => unreachable!(),
+ Entry::Vacant(view) => {
+ assert_eq!(*view.insert(J(1000)), J(1000));
+ }
+ }
+ assert_eq!(map.get::<J>().unwrap(), &J(1000));
+ assert_eq!(map.len(), 6);
+
+ // Entry.or_insert on existing key
+ map.entry::<B>().or_insert(B(71)).0 += 1;
+ assert_eq!(map.get::<B>().unwrap(), &B(201));
+ assert_eq!(map.len(), 6);
+
+ // Entry.or_insert on nonexisting key
+ map.entry::<C>().or_insert(C(300)).0 += 1;
+ assert_eq!(map.get::<C>().unwrap(), &C(301));
+ assert_eq!(map.len(), 7);
+ }
}
- })
+ }
+
+ test_entry!(test_entry_any, AnyMap);
+ test_entry!(test_entry_cloneany, Map<dyn CloneAny>);
+
+ #[test]
+ fn test_default() {
+ let map: AnyMap = Default::default();
+ assert_eq!(map.len(), 0);
+ }
+
+ #[test]
+ fn test_clone() {
+ let mut map: Map<dyn CloneAny> = Map::new();
+ let _ = map.insert(A(1));
+ let _ = map.insert(B(2));
+ let _ = map.insert(D(3));
+ let _ = map.insert(E(4));
+ let _ = map.insert(F(5));
+ let _ = map.insert(J(6));
+ let map2 = map.clone();
+ assert_eq!(map2.len(), 6);
+ assert_eq!(map2.get::<A>(), Some(&A(1)));
+ assert_eq!(map2.get::<B>(), Some(&B(2)));
+ assert_eq!(map2.get::<C>(), None);
+ assert_eq!(map2.get::<D>(), Some(&D(3)));
+ assert_eq!(map2.get::<E>(), Some(&E(4)));
+ assert_eq!(map2.get::<F>(), Some(&F(5)));
+ assert_eq!(map2.get::<J>(), Some(&J(6)));
+ }
+
+ #[test]
+ fn test_varieties() {
+ fn assert_send<T: Send>() { }
+ fn assert_sync<T: Sync>() { }
+ fn assert_clone<T: Clone>() { }
+ fn assert_debug<T: ::core::fmt::Debug>() { }
+ assert_send::<Map<dyn Any + Send>>();
+ assert_send::<Map<dyn Any + Send + Sync>>();
+ assert_sync::<Map<dyn Any + Send + Sync>>();
+ assert_debug::<Map<dyn Any>>();
+ assert_debug::<Map<dyn Any + Send>>();
+ assert_debug::<Map<dyn Any + Send + Sync>>();
+ assert_send::<Map<dyn CloneAny + Send>>();
+ assert_send::<Map<dyn CloneAny + Send + Sync>>();
+ assert_sync::<Map<dyn CloneAny + Send + Sync>>();
+ assert_clone::<Map<dyn CloneAny + Send>>();
+ assert_clone::<Map<dyn CloneAny + Send + Sync>>();
+ assert_clone::<Map<dyn CloneAny + Send + Sync>>();
+ assert_debug::<Map<dyn CloneAny>>();
+ assert_debug::<Map<dyn CloneAny + Send>>();
+ assert_debug::<Map<dyn CloneAny + Send + Sync>>();
+ }
}