X-Git-Url: https://git.chrismorgan.info/anymap/blobdiff_plain/905800cc304d4c341b64f87779e9ab86f0be6800..e04b8b4d6ecf155f4ac9fedde3effe55e5f74ae0:/src/lib.rs

diff --git a/src/lib.rs b/src/lib.rs
index daa6044..560a73d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,361 +1,655 @@
-//! 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.
 
-#![feature(default_type_params, tuple_indexing)]
-#![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 std::any::Any;
-use std::intrinsics::{forget, TypeId};
-use std::collections::HashMap;
-use std::collections::hash_map;
-use std::hash::{Hash, Hasher, Writer};
-use std::mem::{transmute, transmute_copy};
-use std::raw::TraitObject;
-
-pub use Entry::{Vacant, Occupied};
+#![cfg_attr(not(feature = "std"), no_std)]
 
-struct TypeIdHasher;
-
-struct TypeIdState {
-    value: u64,
-}
-
-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)
-        }
-    }
-}
+use core::any::{Any, TypeId};
+use core::convert::TryInto;
+use core::hash::{Hasher, BuildHasherDefault};
+use core::marker::PhantomData;
 
-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
-    }
-}
+#[cfg(not(any(feature = "std", feature = "hashbrown")))]
+compile_error!("anymap: you must enable the 'std' feature or the 'hashbrown' feature");
 
-/// 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 downcast_ref_unchecked<T: 'static>(self) -> &'a T;
-}
+#[cfg(not(feature = "std"))]
+extern crate alloc;
 
-impl<'a> UncheckedAnyRefExt<'a> for &'a (Any + 'a) {
-    #[inline]
-    unsafe fn downcast_ref_unchecked<T: 'static>(self) -> &'a T {
-        // Get the raw representation of the trait object
-        let to: TraitObject = transmute_copy(&self);
+#[cfg(not(feature = "std"))]
+use alloc::boxed::Box;
 
-        // Extract the data pointer
-        transmute(to.data)
-    }
-}
+use any::{Downcast, IntoBox};
+pub use any::CloneAny;
 
-/// 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 downcast_mut_unchecked<T: 'static>(self) -> &'a mut T;
-}
-
-impl<'a> UncheckedAnyMutRefExt<'a> for &'a mut (Any + 'a) {
-    #[inline]
-    unsafe fn downcast_mut_unchecked<T: 'static>(self) -> &'a mut T {
-        // Get the raw representation of the trait object
-        let to: TraitObject = transmute_copy(&self);
-
-        // Extract the data pointer
-        transmute(to.data)
-    }
-}
-
-/// An extension of `BoxAny` allowing unchecked downcasting of trait objects to `Box<T>`.
-trait UncheckedBoxAny {
-    /// Returns 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 downcast_unchecked<T: 'static>(self) -> Box<T>;
-}
+#[cfg(all(feature = "std", not(feature = "hashbrown")))]
+/// A re-export of [`std::collections::hash_map`] for raw access.
+///
+/// If the `hashbrown` feature gets enabled, this will become an export of `hashbrown::hash_map`.
+///
+/// As with [`RawMap`][crate::RawMap], this is exposed for compatibility reasons, since features
+/// are supposed to be additive. This *is* imperfect, since the two modules are incompatible in a
+/// few places (e.g. hashbrown’s entry types have an extra generic parameter), but it’s close, and
+/// much too useful to give up the whole concept.
+pub use std::collections::hash_map as raw_hash_map;
+
+#[cfg(feature = "hashbrown")]
+/// A re-export of [`hashbrown::hash_map`] for raw access.
+///
+/// If the `hashbrown` feature was disabled, this would become an export of
+/// `std::collections::hash_map`.
+///
+/// As with [`RawMap`][crate::RawMap], this is exposed for compatibility reasons, since features
+/// are supposed to be additive. This *is* imperfect, since the two modules are incompatible in a
+/// few places (e.g. hashbrown’s entry types have an extra generic parameter), but it’s close, and
+/// much too useful to give up the whole concept.
+pub use hashbrown::hash_map as raw_hash_map;
 
-impl UncheckedBoxAny for Box<Any + 'static> {
-    #[inline]
-    unsafe fn downcast_unchecked<T: 'static>(self) -> Box<T> {
-        // Get the raw representation of the trait object
-        let to: TraitObject = *transmute::<&Box<Any>, &TraitObject>(&self);
+use self::raw_hash_map::HashMap;
 
-        // Prevent destructor on self being run
-        forget(self);
+mod any;
 
-        // Extract the data pointer
-        transmute(to.data)
-    }
-}
+/// Raw access to the underlying `HashMap`.
+///
+/// This is a public type alias because the underlying `HashMap` could be
+/// `std::collections::HashMap` or `hashbrown::HashMap`, depending on the crate features enabled.
+/// For that reason, you should refer to this type as `anymap::RawMap` rather than
+/// `std::collections::HashMap` to avoid breakage if something else in your crate tree enables
+/// hashbrown.
+///
+/// See also [`raw_hash_map`], an export of the corresponding `hash_map` module.
+pub type RawMap<A> = HashMap<TypeId, Box<A>, BuildHasherDefault<TypeIdHasher>>;
 
-/// A map containing zero or one values for any given type and allowing convenient,
+/// 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]&lt;dyn [core::any::Any]&gt;</code>, also spelled [`AnyMap`] for convenience.
+/// - <code>[Map]&lt;dyn [core::any::Any] + Send&gt;</code>
+/// - <code>[Map]&lt;dyn [core::any::Any] + Send + Sync&gt;</code>
+/// - <code>[Map]&lt;dyn [CloneAny]&gt;</code>
+/// - <code>[Map]&lt;dyn [CloneAny] + Send&gt;</code>
+/// - <code>[Map]&lt;dyn [CloneAny] + Send + Sync&gt;</code>
+///
+/// ## Example
+///
+/// (Here using the [`AnyMap`] convenience alias; the first line could use
+/// <code>[anymap::Map][Map]::&lt;[core::any::Any]&gt;::new()</code> instead if desired.)
+///
 /// ```rust
-/// # use anymap::AnyMap;
-/// let mut data = AnyMap::new();
-/// assert_eq!(data.get(), None::<&int>);
-/// data.insert(42i);
-/// assert_eq!(data.get(), Some(&42i));
-/// data.remove::<int>();
-/// assert_eq!(data.get::<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.get::<Foo>(), None);
-/// data.insert(Foo { str: "foo".to_string() });
-/// assert_eq!(data.get(), Some(&Foo { str: "foo".to_string() }));
+/// 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.as_slice(), "foot");
+/// 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 + Downcast = 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 + Downcast> Clone for Map<A> where Box<A>: Clone {
+    #[inline]
+    fn clone(&self) -> Map<A> {
+        Map {
+            raw: self.raw.clone(),
         }
     }
 }
 
-impl AnyMap {
-    /// Deprecated: Renamed to `get`.
-    #[deprecated = "Renamed to `get`"]
-    pub fn find<T: Any + 'static>(&self) -> Option<&T> {
-        self.get::<T>()
+/// The most common type of `Map`: just using `Any`; <code>[Map]&lt;dyn [Any]&gt;</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<A: ?Sized + Downcast> Default for Map<A> {
+    #[inline]
+    fn default() -> Map<A> {
+        Map::new()
+    }
+}
+
+impl<A: ?Sized + Downcast> Map<A> {
+    /// Create an empty collection.
+    #[inline]
+    pub fn new() -> Map<A> {
+        Map {
+            raw: RawMap::with_hasher(Default::default()),
+        }
+    }
+
+    /// Creates an empty collection with the given initial capacity.
+    #[inline]
+    pub fn with_capacity(capacity: usize) -> Map<A> {
+        Map {
+            raw: RawMap::with_capacity_and_hasher(capacity, Default::default()),
+        }
+    }
+
+    /// Returns the number of elements the collection can hold without reallocating.
+    #[inline]
+    pub fn capacity(&self) -> usize {
+        self.raw.capacity()
+    }
+
+    /// 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.raw.reserve(additional)
+    }
+
+    /// 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.raw.shrink_to_fit()
+    }
+
+    // Additional stable methods (as of 1.60.0-nightly) that could be added:
+    // try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError>    (1.57.0)
+    // shrink_to(&mut self, min_capacity: usize)                                   (1.56.0)
+
+    /// Returns the number of items in the collection.
+    #[inline]
+    pub fn len(&self) -> usize {
+        self.raw.len()
+    }
+
+    /// Returns true if there are no items in the collection.
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.raw.is_empty()
     }
 
-    /// Deprecated: Renamed to `get_mut`.
-    #[deprecated = "Renamed to `get_mut`"]
-    pub fn find_mut<T: Any + 'static>(&mut self) -> Option<&mut T> {
-        self.get_mut::<T>()
+    /// Removes all items from the collection. Keeps the allocated memory for reuse.
+    #[inline]
+    pub fn clear(&mut self) {
+        self.raw.clear()
     }
 
-    /// Retrieve the value stored in the map for the type `T`, if it exists.
-    pub fn get<T: Any + 'static>(&self) -> Option<&T> {
-        self.data.get(&TypeId::of::<T>())
+    /// 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>() })
     }
 
-    /// Retrieve a mutable reference to the value stored in the map for the type `T`, if it exists.
-    pub fn get_mut<T: Any + 'static>(&mut self) -> Option<&mut T> {
-        self.data.get_mut(&TypeId::of::<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>() })
     }
 
-    /// Set the value contained in the map for the type `T`.
-    /// If there is a previous value stored, it will be returned.
-    pub fn insert<T: Any + 'static>(&mut self, value: T) -> Option<T> {
-        self.data.insert(TypeId::of::<T>(), box value as Box<Any>)
-            .map(|any| *unsafe { any.downcast_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> {
+        self.raw.insert(TypeId::of::<T>(), value.into_box())
+            .map(|any| unsafe { *any.downcast_unchecked::<T>() })
     }
 
-    /// Remove and return the value for the type `T` if it existed.
-    pub fn remove<T: Any + 'static>(&mut self) -> Option<T> {
-        self.data.remove(&TypeId::of::<T>())
+    // rustc 1.60.0-nightly has another method try_insert that would be nice to add when stable.
+
+    /// 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>() })
     }
 
-    /// Does a value of type `T` exist?
-    pub fn contains<T: Any + 'static>(&self) -> bool {
-        self.data.contains_key(&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>())
     }
 
-    /// Gets the given key's corresponding entry in the map for in-place manipulation
-    pub fn entry<T: Any + 'static>(&mut self) -> Entry<T> {
-        match self.data.entry(TypeId::of::<T>()) {
-            hash_map::Occupied(e) => Occupied(OccupiedEntry { entry: e }),
-            hash_map::Vacant(e) => Vacant(VacantEntry { entry: e }),
+    /// 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_hash_map::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry {
+                inner: e,
+                type_: PhantomData,
+            }),
+            raw_hash_map::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()
+    /// Get access to the raw hash map that backs this.
+    ///
+    /// This will seldom be useful, but it’s conceivable that you could wish to iterate over all
+    /// the items in the collection, and this lets you do that.
+    ///
+    /// To improve compatibility with Cargo features, interact with this map through the names
+    /// [`anymap::RawMap`][RawMap] and [`anymap::raw_hash_map`][raw_hash_map], rather than through
+    /// `std::collections::{HashMap, hash_map}` or `hashbrown::{HashMap, hash_map}`, for anything
+    /// beyond self methods. Otherwise, if you use std and another crate in the tree enables
+    /// hashbrown, your code will break.
+    #[inline]
+    pub fn as_raw(&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()
+    /// Get mutable access to the raw hash map that backs this.
+    ///
+    /// This will seldom be useful, but it’s conceivable that you could wish to iterate over all
+    /// the items in the collection mutably, or drain or something, or *possibly* even batch
+    /// insert, and this lets you do that.
+    ///
+    /// To improve compatibility with Cargo features, interact with this map through the names
+    /// [`anymap::RawMap`][RawMap] and [`anymap::raw_hash_map`][raw_hash_map], rather than through
+    /// `std::collections::{HashMap, hash_map}` or `hashbrown::{HashMap, hash_map}`, for anything
+    /// beyond self methods. Otherwise, if you use std and another crate in the tree enables
+    /// hashbrown, your code will break.
+    ///
+    /// # Safety
+    ///
+    /// If you insert any values to the raw map, the key (a `TypeId`) must match the value’s type,
+    /// or *undefined behaviour* will occur when you access those values.
+    ///
+    /// (*Removing* entries is perfectly safe.)
+    #[inline]
+    pub unsafe fn as_raw_mut(&mut self) -> &mut RawMap<A> {
+        &mut self.raw
     }
 
-    /// Removes all items from the collection.
-    pub fn clear(&mut self) {
-        self.data.clear();
+    /// Convert this into the raw hash map that backs this.
+    ///
+    /// This will seldom be useful, but it’s conceivable that you could wish to consume all the
+    /// items in the collection and do *something* with some or all of them, and this lets you do
+    /// that, without the `unsafe` that `.as_raw_mut().drain()` would require.
+    ///
+    /// To improve compatibility with Cargo features, interact with this map through the names
+    /// [`anymap::RawMap`][RawMap] and [`anymap::raw_hash_map`][raw_hash_map], rather than through
+    /// `std::collections::{HashMap, hash_map}` or `hashbrown::{HashMap, hash_map}`, for anything
+    /// beyond self methods. Otherwise, if you use std and another crate in the tree enables
+    /// hashbrown, your code will break.
+    #[inline]
+    pub fn into_raw(self) -> RawMap<A> {
+        self.raw
+    }
+
+    /// Construct a map from a collection of raw values.
+    ///
+    /// You know what? I can’t immediately think of any legitimate use for this, especially because
+    /// of the requirement of the `BuildHasherDefault<TypeIdHasher>` generic in the map.
+    ///
+    /// Perhaps this will be most practical as `unsafe { Map::from_raw(iter.collect()) }`, iter
+    /// being an iterator over `(TypeId, Box<A>)` pairs. Eh, this method provides symmetry with
+    /// `into_raw`, so I don’t care if literally no one ever uses it. I’m not even going to write a
+    /// test for it, it’s so trivial.
+    ///
+    /// To improve compatibility with Cargo features, interact with this map through the names
+    /// [`anymap::RawMap`][RawMap] and [`anymap::raw_hash_map`][raw_hash_map], rather than through
+    /// `std::collections::{HashMap, hash_map}` or `hashbrown::{HashMap, hash_map}`, for anything
+    /// beyond self methods. Otherwise, if you use std and another crate in the tree enables
+    /// hashbrown, your code will break.
+    ///
+    /// # Safety
+    ///
+    /// For all entries in the raw map, the key (a `TypeId`) must match the value’s type,
+    /// or *undefined behaviour* will occur when you access that entry.
+    #[inline]
+    pub unsafe fn from_raw(raw: RawMap<A>) -> Map<A> {
+        Self { raw }
     }
 }
 
-/// A view into a single occupied location in a HashMap
-pub struct OccupiedEntry<'a, V: 'a> {
-    entry: hash_map::OccupiedEntry<'a, TypeId, Box<Any + 'static>>,
+impl<A: ?Sized + Downcast> Extend<Box<A>> for Map<A> {
+    #[inline]
+    fn extend<T: IntoIterator<Item = Box<A>>>(&mut self, iter: T) {
+        for item in iter {
+            let _ = self.raw.insert(Downcast::type_id(&*item), item);
+        }
+    }
 }
 
-/// A view into a single empty location in a HashMap
-pub struct VacantEntry<'a, V: 'a> {
-    entry: hash_map::VacantEntry<'a, TypeId, Box<Any + 'static>>,
+/// A view into a single occupied location in an `Map`.
+pub struct OccupiedEntry<'a, A: ?Sized + Downcast, V: 'a> {
+    #[cfg(all(feature = "std", not(feature = "hashbrown")))]
+    inner: raw_hash_map::OccupiedEntry<'a, TypeId, Box<A>>,
+    #[cfg(feature = "hashbrown")]
+    inner: raw_hash_map::OccupiedEntry<'a, TypeId, Box<A>, BuildHasherDefault<TypeIdHasher>>,
+    type_: PhantomData<V>,
 }
 
-/// A view into a single location in a map, which may be vacant or occupied
-pub enum Entry<'a, V: 'a> {
+/// A view into a single empty location in an `Map`.
+pub struct VacantEntry<'a, A: ?Sized + Downcast, V: 'a> {
+    #[cfg(all(feature = "std", not(feature = "hashbrown")))]
+    inner: raw_hash_map::VacantEntry<'a, TypeId, Box<A>>,
+    #[cfg(feature = "hashbrown")]
+    inner: raw_hash_map::VacantEntry<'a, TypeId, Box<A>, BuildHasherDefault<TypeIdHasher>>,
+    type_: PhantomData<V>,
+}
+
+/// A view into a single location in an `Map`, which may be vacant or occupied.
+pub enum Entry<'a, A: ?Sized + Downcast, V: 'a> {
     /// An occupied Entry
-    Occupied(OccupiedEntry<'a, V>),
+    Occupied(OccupiedEntry<'a, A, V>),
     /// A vacant Entry
-    Vacant(VacantEntry<'a, V>),
+    Vacant(VacantEntry<'a, A, V>),
 }
 
-impl<'a, V: 'static> OccupiedEntry<'a, V> {
+impl<'a, A: ?Sized + Downcast, 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()),
+        }
+    }
+
+    /// Ensures a value is in the entry by inserting the default value if empty,
+    /// and returns a mutable reference to the value in the entry.
+    #[inline]
+    pub fn or_default(self) -> &'a mut V where V: Default {
+        match self {
+            Entry::Occupied(inner) => inner.into_mut(),
+            Entry::Vacant(inner) => inner.insert(Default::default()),
+        }
+    }
+
+    /// Provides in-place mutable access to an occupied entry before any potential inserts into the
+    /// map.
+    #[inline]
+    pub fn and_modify<F: FnOnce(&mut V)>(self, f: F) -> Self {
+        match self {
+            Entry::Occupied(mut inner) => {
+                f(inner.get_mut());
+                Entry::Occupied(inner)
+            },
+            Entry::Vacant(inner) => Entry::Vacant(inner),
+        }
+    }
+
+    // Additional stable methods (as of 1.60.0-nightly) that could be added:
+    // insert_entry(self, value: V) -> OccupiedEntry<'a, K, V>                             (1.59.0)
+}
+
+impl<'a, A: ?Sized + Downcast, V: IntoBox<A>> OccupiedEntry<'a, A, V> {
     /// Gets a reference to the value in the entry
+    #[inline]
     pub fn get(&self) -> &V {
-        unsafe { self.entry.get().downcast_ref_unchecked() }
+        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.entry.get_mut().downcast_mut_unchecked() }
+        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 map itself
+    /// with a lifetime bound to the collection itself
+    #[inline]
     pub fn into_mut(self) -> &'a mut V {
-        unsafe { self.entry.into_mut().downcast_mut_unchecked() }
+        unsafe { self.inner.into_mut().downcast_mut_unchecked() }
     }
 
     /// Sets the value of the entry, and returns the entry's old value
-    pub fn set(&mut self, value: V) -> V {
-        unsafe { *self.entry.set(box value as Box<Any + 'static>).downcast_unchecked() }
+    #[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
-    pub fn take(self) -> V {
-        unsafe { *self.entry.take().downcast_unchecked() }
+    #[inline]
+    pub fn remove(self) -> V {
+        unsafe { *self.inner.remove().downcast_unchecked() }
     }
 }
 
-impl<'a, V: 'static> VacantEntry<'a, V> {
+impl<'a, A: ?Sized + Downcast, 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
-    pub fn set(self, value: V) -> &'a mut V {
-        unsafe { self.entry.set(box value as Box<Any + 'static>).downcast_mut_unchecked() }
+    #[inline]
+    pub fn insert(self, value: V) -> &'a mut V {
+        unsafe { self.inner.insert(value.into_box()).downcast_mut_unchecked() }
     }
 }
 
-#[bench]
-fn bench_insertion(b: &mut ::test::Bencher) {
-    b.iter(|| {
-        let mut data = AnyMap::new();
-        for _ in range(0u, 100) {
-            let _ = data.insert(42i);
-        }
-    })
+/// A hasher designed to eke a little more speed out, given `TypeId`’s known characteristics.
+///
+/// Specifically, this is a no-op hasher that expects to be fed a u64’s worth of
+/// randomly-distributed bits. It works well for `TypeId` (eliminating start-up time, so that my
+/// get_missing benchmark is ~30ns rather than ~900ns, and being a good deal faster after that, so
+/// that my insert_and_get_on_260_types benchmark is ~12μs instead of ~21.5μs), but will
+/// panic in debug mode and always emit zeros in release mode for any other sorts of inputs, so
+/// yeah, don’t use it! 😀
+#[derive(Default)]
+pub struct TypeIdHasher {
+    value: u64,
 }
 
-#[bench]
-fn bench_get_missing(b: &mut ::test::Bencher) {
-    b.iter(|| {
-        let data = AnyMap::new();
-        for _ in range(0u, 100) {
-            assert_eq!(data.get(), None::<&int>);
-        }
-    })
-}
+impl Hasher for TypeIdHasher {
+    #[inline]
+    fn write(&mut self, bytes: &[u8]) {
+        // This expects to receive exactly one 64-bit value, and there’s no realistic chance of
+        // that changing, but I don’t want to depend on something that isn’t expressly part of the
+        // contract for safety. But I’m OK with release builds putting everything in one bucket
+        // if it *did* change (and debug builds panicking).
+        debug_assert_eq!(bytes.len(), 8);
+        let _ = bytes.try_into()
+            .map(|array| self.value = u64::from_ne_bytes(array));
+    }
 
-#[bench]
-fn bench_get_present(b: &mut ::test::Bencher) {
-    b.iter(|| {
-        let mut data = AnyMap::new();
-        let _ = data.insert(42i);
-        // These inner loops are a feeble attempt to drown the other factors.
-        for _ in range(0u, 100) {
-            assert_eq!(data.get(), Some(&42i));
-        }
-    })
+    #[inline]
+    fn finish(&self) -> u64 { self.value }
 }
 
-#[test]
-fn test_entry() {
-    #[deriving(Show, PartialEq)] struct A(int);
-    #[deriving(Show, PartialEq)] struct B(int);
-    #[deriving(Show, PartialEq)] struct C(int);
-    #[deriving(Show, PartialEq)] struct D(int);
-    #[deriving(Show, PartialEq)] struct E(int);
-    #[deriving(Show, PartialEq)] struct F(int);
-    #[deriving(Show, PartialEq)] struct J(int);
-
-    let mut map: AnyMap = AnyMap::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>() {
-        Vacant(_) => unreachable!(),
-        Occupied(mut view) => {
-            assert_eq!(view.get(), &A(10));
-            assert_eq!(view.set(A(100)), A(10));
+#[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);
+            }
         }
     }
-    assert_eq!(map.get::<A>().unwrap(), &A(100));
-    assert_eq!(map.len(), 6);
 
+    test_entry!(test_entry_any, AnyMap);
+    test_entry!(test_entry_cloneany, Map<dyn CloneAny>);
 
-    // Existing key (update)
-    match map.entry::<B>() {
-        Vacant(_) => unreachable!(),
-        Occupied(mut view) => {
-            let v = view.get_mut();
-            let new_v = B(v.0 * 10);
-            *v = new_v;
-        }
+    #[test]
+    fn test_default() {
+        let map: AnyMap = Default::default();
+        assert_eq!(map.len(), 0);
     }
-    assert_eq!(map.get().unwrap(), &B(200));
-    assert_eq!(map.len(), 6);
-
 
-    // Existing key (take)
-    match map.entry::<C>() {
-        Vacant(_) => unreachable!(),
-        Occupied(view) => {
-            assert_eq!(view.take(), C(30));
-        }
+    #[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)));
     }
-    assert_eq!(map.get::<C>(), None);
-    assert_eq!(map.len(), 5);
 
+    #[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>>();
+    }
 
-    // Inexistent key (insert)
-    match map.entry::<J>() {
-        Occupied(_) => unreachable!(),
-        Vacant(view) => {
-            assert_eq!(*view.set(J(1000)), J(1000));
+    #[test]
+    fn type_id_hasher() {
+        #[cfg(not(feature = "std"))]
+        use alloc::vec::Vec;
+        use core::hash::Hash;
+        fn verify_hashing_with(type_id: TypeId) {
+            let mut hasher = TypeIdHasher::default();
+            type_id.hash(&mut hasher);
+            // SAFETY: u64 is valid for all bit patterns.
+            assert_eq!(hasher.finish(), unsafe { core::mem::transmute::<TypeId, u64>(type_id) });
         }
+        // Pick a variety of types, just to demonstrate it’s all sane. Normal, zero-sized, unsized, &c.
+        verify_hashing_with(TypeId::of::<usize>());
+        verify_hashing_with(TypeId::of::<()>());
+        verify_hashing_with(TypeId::of::<str>());
+        verify_hashing_with(TypeId::of::<&str>());
+        verify_hashing_with(TypeId::of::<Vec<u8>>());
+    }
+
+    #[test]
+    fn test_extend() {
+        let mut map = AnyMap::new();
+        map.extend([Box::new(123) as Box<dyn Any>, Box::new(456), Box::new(true)]);
+        assert_eq!(map.get(), Some(&456));
+        assert_eq!(map.get::<bool>(), Some(&true));
+        assert!(map.get::<Box<dyn Any>>().is_none());
     }
-    assert_eq!(map.get::<J>().unwrap(), &J(1000));
-    assert_eq!(map.len(), 6);
 }