diff --git a/CHANGELOG.md b/CHANGELOG.md index 8dd437e..5fad564 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -7,6 +7,15 @@ being bigger than I’d earlier intended. - Fixed the broken `Extend` implementation added in 1.0.0-beta.1. +- Split the hashbrown implementation into a new module, `hashbrown`: + std and hashbrown can now coexist completely peacefully, + with `anymap::Map` being powered by `std::collections::hash_map`, + and `anymap::hashbrown::Map` being powered by `hashbrown::hash_map`. + The `raw_hash_map` alias, provided in 1.0.0-beta.1 because of the ambiguity + of what backed `anymap::Map`, is removed as superfluous and useless. + `RawMap` remains, despite not being *required*, as an ergonomic improvement. + With this, we’re back to proper completely additive Cargo features. + # 1.0.0-beta.1 (2022-01-25) - Removed `anymap::any::Any` in favour of just plain `core::any::Any`, since its diff --git a/Cargo.toml b/Cargo.toml index 02d16c7..aca1a64 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -11,6 +11,9 @@ categories = ["rust-patterns", "data-structures", "no-std"] license = "BlueOak-1.0.0 OR MIT OR Apache-2.0" include = ["/README.md", "/COPYING", "/CHANGELOG.md", "/src"] +[package.metadata.docs.rs] +all-features = true + [features] default = ["std"] std = [] diff --git a/README.md b/README.md index 798f925..d0af879 100644 --- a/README.md +++ b/README.md @@ -41,22 +41,20 @@ assert_eq!(&*data.get::().unwrap().str, "foot"); ## Cargo features/dependencies/usage -Typical Cargo.toml usage: +Typical Cargo.toml usage, providing `anymap::AnyMap` *et al.* backed by `std::collections::HashMap`: ```toml [dependencies] anymap = "1.0.0-beta.1" ``` -No-std usage, using `alloc` and the [hashbrown](https://rust-lang.github.io/hashbrown) crate instead of `std::collections::HashMap`: +No-std usage, providing `anymap::hashbrown::AnyMap` *et al.* (note the different path, required because Cargo features are additive) backed by `alloc` and the [hashbrown](https://rust-lang.github.io/hashbrown) crate: ```toml [dependencies] anymap = { version = "1.0.0-beta.1", default-features = false, features = ["hashbrown"] } ``` -The `std` feature is enabled by default. The `hashbrown` feature overrides it. At least one of the two must be enabled. - **On stability:** hashbrown is still pre-1.0.0 and experiencing breaking changes. Because it’s useful for a small fraction of users, I am retaining it, but with *different compatibility guarantees to the typical SemVer ones*. Where possible, I will just widen the range for new releases of hashbrown, but if an incompatible change occurs, I may drop support for older versions of hashbrown with a bump to the *minor* part of the anymap version number (e.g. 1.1.0, 1.2.0). Iff you’re using this feature, this is cause to *consider* using a tilde requirement like `"~1.0"` (or spell it out as `>=1, <1.1`). ## Unsafe code in this library diff --git a/src/lib.rs b/src/lib.rs index 560a73d..9c57f09 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -1,464 +1,599 @@ //! This crate provides a safe and convenient store for one value of each type. //! //! Your starting point is [`Map`]. It has an example. +//! +//! # Cargo features +//! +//! This crate has two independent features, each of which provides an implementation providing +//! types `Map`, `AnyMap`, `OccupiedEntry`, `VacantEntry`, `Entry` and `RawMap`: +//! +#![cfg_attr(feature = "std", doc = " - **std** (default, *enabled* in this build):")] +#![cfg_attr(not(feature = "std"), doc = " - **std** (default, *disabled* in this build):")] +//! an implementation using `std::collections::hash_map`, placed in the crate root +//! (e.g. `anymap::AnyMap`). +//! +#![cfg_attr(feature = "hashbrown", doc = " - **hashbrown** (optional; *enabled* in this build):")] +#![cfg_attr(not(feature = "hashbrown"), doc = " - **hashbrown** (optional; *disabled* in this build):")] +//! an implementation using `alloc` and `hashbrown::hash_map`, placed in a module `hashbrown` +//! (e.g. `anymap::hashbrown::AnyMap`). #![warn(missing_docs, unused_results)] #![cfg_attr(not(feature = "std"), no_std)] -use core::any::{Any, TypeId}; use core::convert::TryInto; -use core::hash::{Hasher, BuildHasherDefault}; -use core::marker::PhantomData; - -#[cfg(not(any(feature = "std", feature = "hashbrown")))] -compile_error!("anymap: you must enable the 'std' feature or the 'hashbrown' feature"); +use core::hash::Hasher; #[cfg(not(feature = "std"))] extern crate alloc; -#[cfg(not(feature = "std"))] -use alloc::boxed::Box; - -use any::{Downcast, IntoBox}; -pub use any::CloneAny; - -#[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; - -use self::raw_hash_map::HashMap; +pub use crate::any::CloneAny; mod any; -/// 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 = HashMap, BuildHasherDefault>; +#[cfg(any(feature = "std", feature = "hashbrown"))] +macro_rules! everything { + ($example_init:literal, $($parent:ident)::+ $(, $entry_generics:ty)?) => { + use core::any::{Any, TypeId}; + use core::hash::BuildHasherDefault; + use core::marker::PhantomData; -/// 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`) to add those auto -/// traits. -/// -/// Cumulatively, there are thus six forms of map: -/// -/// - [Map]<dyn [core::any::Any]>, also spelled [`AnyMap`] for convenience. -/// - [Map]<dyn [core::any::Any] + Send> -/// - [Map]<dyn [core::any::Any] + Send + Sync> -/// - [Map]<dyn [CloneAny]> -/// - [Map]<dyn [CloneAny] + Send> -/// - [Map]<dyn [CloneAny] + Send + Sync> -/// -/// ## Example -/// -/// (Here using the [`AnyMap`] convenience alias; the first line could use -/// [anymap::Map][Map]::<[core::any::Any]>::new() instead if desired.) -/// -/// ```rust -/// let mut data = anymap::AnyMap::new(); -/// assert_eq!(data.get(), None::<&i32>); -/// data.insert(42i32); -/// assert_eq!(data.get(), Some(&42i32)); -/// data.remove::(); -/// assert_eq!(data.get::(), None); -/// -/// #[derive(Clone, PartialEq, Debug)] -/// struct Foo { -/// str: String, -/// } -/// -/// assert_eq!(data.get::(), None); -/// data.insert(Foo { str: format!("foo") }); -/// assert_eq!(data.get(), Some(&Foo { str: format!("foo") })); -/// data.get_mut::().map(|foo| foo.str.push('t')); -/// assert_eq!(&*data.get::().unwrap().str, "foot"); -/// ``` -/// -/// Values containing non-static references are not permitted. -#[derive(Debug)] -pub struct Map { - raw: RawMap, -} + #[cfg(not(feature = "std"))] + use alloc::boxed::Box; -// #[derive(Clone)] would want A to implement Clone, but in reality it’s only Box that can. -impl Clone for Map where Box: Clone { - #[inline] - fn clone(&self) -> Map { - Map { - raw: self.raw.clone(), + use ::$($parent)::+::hash_map::{self, HashMap}; + + use crate::any::{Downcast, IntoBox}; + + /// Raw access to the underlying `HashMap`. + /// + /// This alias is provided for convenience because of the ugly third generic parameter. + pub type RawMap = HashMap, BuildHasherDefault>; + + /// 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`) to add those + /// auto traits. + /// + /// Cumulatively, there are thus six forms of map: + /// + /// - [Map]<dyn [core::any::Any]>, + /// also spelled [`AnyMap`] for convenience. + /// - [Map]<dyn [core::any::Any] + Send> + /// - [Map]<dyn [core::any::Any] + Send + Sync> + /// - [Map]<dyn [CloneAny]> + /// - [Map]<dyn [CloneAny] + Send> + /// - [Map]<dyn [CloneAny] + Send + Sync> + /// + /// ## Example + /// + /// (Here using the [`AnyMap`] convenience alias; the first line could use + /// [anymap::Map][Map]::<[core::any::Any]>::new() instead if desired.) + /// + /// ```rust + #[doc = $example_init] + /// assert_eq!(data.get(), None::<&i32>); + /// data.insert(42i32); + /// assert_eq!(data.get(), Some(&42i32)); + /// data.remove::(); + /// assert_eq!(data.get::(), None); + /// + /// #[derive(Clone, PartialEq, Debug)] + /// struct Foo { + /// str: String, + /// } + /// + /// assert_eq!(data.get::(), None); + /// data.insert(Foo { str: format!("foo") }); + /// assert_eq!(data.get(), Some(&Foo { str: format!("foo") })); + /// data.get_mut::().map(|foo| foo.str.push('t')); + /// assert_eq!(&*data.get::().unwrap().str, "foot"); + /// ``` + /// + /// Values containing non-static references are not permitted. + #[derive(Debug)] + pub struct Map { + raw: RawMap, } - } + + // #[derive(Clone)] would want A to implement Clone, but in reality only Box can. + impl Clone for Map where Box: Clone { + #[inline] + fn clone(&self) -> Map { + Map { + raw: self.raw.clone(), + } + } + } + + /// The most common type of `Map`: just using `Any`; [Map]<dyn [Any]>. + /// + /// Why is this a separate type alias rather than a default value for `Map`? + /// `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; + + impl Default for Map { + #[inline] + fn default() -> Map { + Map::new() + } + } + + impl Map { + /// Create an empty collection. + #[inline] + pub fn new() -> Map { + Map { + raw: RawMap::with_hasher(Default::default()), + } + } + + /// Creates an empty collection with the given initial capacity. + #[inline] + pub fn with_capacity(capacity: usize) -> Map { + 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() + } + + /// Removes all items from the collection. Keeps the allocated memory for reuse. + #[inline] + pub fn clear(&mut self) { + self.raw.clear() + } + + /// Returns a reference to the value stored in the collection for the type `T`, + /// if it exists. + #[inline] + pub fn get>(&self) -> Option<&T> { + self.raw.get(&TypeId::of::()) + .map(|any| unsafe { any.downcast_ref_unchecked::() }) + } + + /// Returns a mutable reference to the value stored in the collection for the type `T`, + /// if it exists. + #[inline] + pub fn get_mut>(&mut self) -> Option<&mut T> { + self.raw.get_mut(&TypeId::of::()) + .map(|any| unsafe { any.downcast_mut_unchecked::() }) + } + + /// 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>(&mut self, value: T) -> Option { + self.raw.insert(TypeId::of::(), value.into_box()) + .map(|any| unsafe { *any.downcast_unchecked::() }) + } + + // rustc 1.60.0-nightly has another method try_insert that would be nice 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>(&mut self) -> Option { + self.raw.remove(&TypeId::of::()) + .map(|any| *unsafe { any.downcast_unchecked::() }) + } + + /// Returns true if the collection contains a value of type `T`. + #[inline] + pub fn contains>(&self) -> bool { + self.raw.contains_key(&TypeId::of::()) + } + + /// Gets the entry for the given type in the collection for in-place manipulation + #[inline] + pub fn entry>(&mut self) -> Entry { + match self.raw.entry(TypeId::of::()) { + hash_map::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry { + inner: e, + type_: PhantomData, + }), + hash_map::Entry::Vacant(e) => Entry::Vacant(VacantEntry { + inner: e, + type_: PhantomData, + }), + } + } + + /// 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. + #[inline] + pub fn as_raw(&self) -> &RawMap { + &self.raw + } + + /// 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. + /// + /// # 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 { + &mut self.raw + } + + /// 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. + #[inline] + pub fn into_raw(self) -> RawMap { + 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` generic in the + /// map. + /// + /// Perhaps this will be most practical as `unsafe { Map::from_raw(iter.collect()) }`, + /// `iter` being an iterator over `(TypeId, Box)` 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. + /// + /// # 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) -> Map { + Self { raw } + } + } + + impl Extend> for Map { + #[inline] + fn extend>>(&mut self, iter: T) { + for item in iter { + let _ = self.raw.insert(Downcast::type_id(&*item), item); + } + } + } + + /// A view into a single occupied location in an `Map`. + pub struct OccupiedEntry<'a, A: ?Sized + Downcast, V: 'a> { + inner: hash_map::OccupiedEntry<'a, TypeId, Box, $($entry_generics)?>, + type_: PhantomData, + } + + /// A view into a single empty location in an `Map`. + pub struct VacantEntry<'a, A: ?Sized + Downcast, V: 'a> { + inner: hash_map::VacantEntry<'a, TypeId, Box, $($entry_generics)?>, + type_: PhantomData, + } + + /// 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, A, V>), + /// A vacant Entry + Vacant(VacantEntry<'a, A, V>), + } + + impl<'a, A: ?Sized + Downcast, V: IntoBox> 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 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(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> 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() } + } + } + + impl<'a, A: ?Sized + Downcast, V: IntoBox> 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 crate::CloneAny; + 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::() { + 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::().unwrap(), &A(100)); + assert_eq!(map.len(), 6); + + + // Existing key (update) + match map.entry::() { + 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::().unwrap(), &B(200)); + assert_eq!(map.len(), 6); + + + // Existing key (remove) + match map.entry::() { + Entry::Vacant(_) => unreachable!(), + Entry::Occupied(view) => { + assert_eq!(view.remove(), C(30)); + } + } + assert_eq!(map.get::(), None); + assert_eq!(map.len(), 5); + + + // Inexistent key (insert) + match map.entry::() { + Entry::Occupied(_) => unreachable!(), + Entry::Vacant(view) => { + assert_eq!(*view.insert(J(1000)), J(1000)); + } + } + assert_eq!(map.get::().unwrap(), &J(1000)); + assert_eq!(map.len(), 6); + + // Entry.or_insert on existing key + map.entry::().or_insert(B(71)).0 += 1; + assert_eq!(map.get::().unwrap(), &B(201)); + assert_eq!(map.len(), 6); + + // Entry.or_insert on nonexisting key + map.entry::().or_insert(C(300)).0 += 1; + assert_eq!(map.get::().unwrap(), &C(301)); + assert_eq!(map.len(), 7); + } + } + } + + test_entry!(test_entry_any, AnyMap); + test_entry!(test_entry_cloneany, Map); + + #[test] + fn test_default() { + let map: AnyMap = Default::default(); + assert_eq!(map.len(), 0); + } + + #[test] + fn test_clone() { + let mut map: Map = 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::(), Some(&A(1))); + assert_eq!(map2.get::(), Some(&B(2))); + assert_eq!(map2.get::(), None); + assert_eq!(map2.get::(), Some(&D(3))); + assert_eq!(map2.get::(), Some(&E(4))); + assert_eq!(map2.get::(), Some(&F(5))); + assert_eq!(map2.get::(), Some(&J(6))); + } + + #[test] + fn test_varieties() { + fn assert_send() { } + fn assert_sync() { } + fn assert_clone() { } + fn assert_debug() { } + assert_send::>(); + assert_send::>(); + assert_sync::>(); + assert_debug::>(); + assert_debug::>(); + assert_debug::>(); + assert_send::>(); + assert_send::>(); + assert_sync::>(); + assert_clone::>(); + assert_clone::>(); + assert_clone::>(); + assert_debug::>(); + assert_debug::>(); + assert_debug::>(); + } + + #[test] + fn test_extend() { + let mut map = AnyMap::new(); + // (vec![] for 1.36.0 compatibility; more recently, you should use [] instead.) + #[cfg(not(feature = "std"))] + use alloc::vec; + map.extend(vec![Box::new(123) as Box, Box::new(456), Box::new(true)]); + assert_eq!(map.get(), Some(&456)); + assert_eq!(map.get::(), Some(&true)); + assert!(map.get::>().is_none()); + } + } + }; } -/// The most common type of `Map`: just using `Any`; [Map]<dyn [Any]>. +#[cfg(feature = "std")] +everything!( + "let mut data = anymap::AnyMap::new();", + std::collections +); + +#[cfg(feature = "hashbrown")] +/// AnyMap backed by `hashbrown`. /// -/// Why is this a separate type alias rather than a default value for `Map`? `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; +/// This depends on the `hashbrown` Cargo feature being enabled. +pub mod hashbrown { + use crate::TypeIdHasher; + #[cfg(doc)] + use crate::any::CloneAny; -impl Default for Map { - #[inline] - fn default() -> Map { - Map::new() - } -} - -impl Map { - /// Create an empty collection. - #[inline] - pub fn new() -> Map { - Map { - raw: RawMap::with_hasher(Default::default()), - } - } - - /// Creates an empty collection with the given initial capacity. - #[inline] - pub fn with_capacity(capacity: usize) -> Map { - 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() - } - - /// Removes all items from the collection. Keeps the allocated memory for reuse. - #[inline] - pub fn clear(&mut self) { - self.raw.clear() - } - - /// Returns a reference to the value stored in the collection for the type `T`, if it exists. - #[inline] - pub fn get>(&self) -> Option<&T> { - self.raw.get(&TypeId::of::()) - .map(|any| unsafe { any.downcast_ref_unchecked::() }) - } - - /// Returns a mutable reference to the value stored in the collection for the type `T`, - /// if it exists. - #[inline] - pub fn get_mut>(&mut self) -> Option<&mut T> { - self.raw.get_mut(&TypeId::of::()) - .map(|any| unsafe { any.downcast_mut_unchecked::() }) - } - - /// 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>(&mut self, value: T) -> Option { - self.raw.insert(TypeId::of::(), value.into_box()) - .map(|any| unsafe { *any.downcast_unchecked::() }) - } - - // 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>(&mut self) -> Option { - self.raw.remove(&TypeId::of::()) - .map(|any| *unsafe { any.downcast_unchecked::() }) - } - - /// Returns true if the collection contains a value of type `T`. - #[inline] - pub fn contains>(&self) -> bool { - self.raw.contains_key(&TypeId::of::()) - } - - /// Gets the entry for the given type in the collection for in-place manipulation - #[inline] - pub fn entry>(&mut self) -> Entry { - match self.raw.entry(TypeId::of::()) { - 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, - }), - } - } - - /// 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 { - &self.raw - } - - /// 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 { - &mut self.raw - } - - /// 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 { - 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` generic in the map. - /// - /// Perhaps this will be most practical as `unsafe { Map::from_raw(iter.collect()) }`, iter - /// being an iterator over `(TypeId, Box)` 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) -> Map { - Self { raw } - } -} - -impl Extend> for Map { - #[inline] - fn extend>>(&mut self, iter: T) { - for item in iter { - let _ = self.raw.insert(Downcast::type_id(&*item), item); - } - } -} - -/// 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>, - #[cfg(feature = "hashbrown")] - inner: raw_hash_map::OccupiedEntry<'a, TypeId, Box, BuildHasherDefault>, - type_: PhantomData, -} - -/// 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>, - #[cfg(feature = "hashbrown")] - inner: raw_hash_map::VacantEntry<'a, TypeId, Box, BuildHasherDefault>, - type_: PhantomData, -} - -/// 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, A, V>), - /// A vacant Entry - Vacant(VacantEntry<'a, A, V>), -} - -impl<'a, A: ?Sized + Downcast, V: IntoBox> 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 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(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> 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() } - } -} - -impl<'a, A: ?Sized + Downcast, V: IntoBox> 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() } - } + everything!( + "let mut data = anymap::hashbrown::AnyMap::new();", + hashbrown, + BuildHasherDefault + ); } /// A hasher designed to eke a little more speed out, given `TypeId`’s known characteristics. @@ -490,166 +625,22 @@ impl Hasher for TypeIdHasher { fn finish(&self) -> u64 { self.value } } -#[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::() { - 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::().unwrap(), &A(100)); - assert_eq!(map.len(), 6); - - - // Existing key (update) - match map.entry::() { - 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::().unwrap(), &B(200)); - assert_eq!(map.len(), 6); - - - // Existing key (remove) - match map.entry::() { - Entry::Vacant(_) => unreachable!(), - Entry::Occupied(view) => { - assert_eq!(view.remove(), C(30)); - } - } - assert_eq!(map.get::(), None); - assert_eq!(map.len(), 5); - - - // Inexistent key (insert) - match map.entry::() { - Entry::Occupied(_) => unreachable!(), - Entry::Vacant(view) => { - assert_eq!(*view.insert(J(1000)), J(1000)); - } - } - assert_eq!(map.get::().unwrap(), &J(1000)); - assert_eq!(map.len(), 6); - - // Entry.or_insert on existing key - map.entry::().or_insert(B(71)).0 += 1; - assert_eq!(map.get::().unwrap(), &B(201)); - assert_eq!(map.len(), 6); - - // Entry.or_insert on nonexisting key - map.entry::().or_insert(C(300)).0 += 1; - assert_eq!(map.get::().unwrap(), &C(301)); - assert_eq!(map.len(), 7); - } - } - } - - test_entry!(test_entry_any, AnyMap); - test_entry!(test_entry_cloneany, Map); - - #[test] - fn test_default() { - let map: AnyMap = Default::default(); - assert_eq!(map.len(), 0); - } - - #[test] - fn test_clone() { - let mut map: Map = 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::(), Some(&A(1))); - assert_eq!(map2.get::(), Some(&B(2))); - assert_eq!(map2.get::(), None); - assert_eq!(map2.get::(), Some(&D(3))); - assert_eq!(map2.get::(), Some(&E(4))); - assert_eq!(map2.get::(), Some(&F(5))); - assert_eq!(map2.get::(), Some(&J(6))); - } - - #[test] - fn test_varieties() { - fn assert_send() { } - fn assert_sync() { } - fn assert_clone() { } - fn assert_debug() { } - assert_send::>(); - assert_send::>(); - assert_sync::>(); - assert_debug::>(); - assert_debug::>(); - assert_debug::>(); - assert_send::>(); - assert_send::>(); - assert_sync::>(); - assert_clone::>(); - assert_clone::>(); - assert_clone::>(); - assert_debug::>(); - assert_debug::>(); - assert_debug::>(); - } - - #[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::(type_id) }); - } - // Pick a variety of types, just to demonstrate it’s all sane. Normal, zero-sized, unsized, &c. - verify_hashing_with(TypeId::of::()); - verify_hashing_with(TypeId::of::<()>()); - verify_hashing_with(TypeId::of::()); - verify_hashing_with(TypeId::of::<&str>()); - verify_hashing_with(TypeId::of::>()); - } - - #[test] - fn test_extend() { - let mut map = AnyMap::new(); - map.extend([Box::new(123) as Box, Box::new(456), Box::new(true)]); - assert_eq!(map.get(), Some(&456)); - assert_eq!(map.get::(), Some(&true)); - assert!(map.get::>().is_none()); +#[test] +fn type_id_hasher() { + #[cfg(not(feature = "std"))] + use alloc::vec::Vec; + use core::hash::Hash; + use core::any::TypeId; + 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::(type_id) }); } + // Pick a variety of types, just to demonstrate it’s all sane. Normal, zero-sized, unsized, &c. + verify_hashing_with(TypeId::of::()); + verify_hashing_with(TypeId::of::<()>()); + verify_hashing_with(TypeId::of::()); + verify_hashing_with(TypeId::of::<&str>()); + verify_hashing_with(TypeId::of::>()); } diff --git a/test b/test index f635904..49f9775 100755 --- a/test +++ b/test @@ -4,11 +4,10 @@ export RUSTFLAGS="-D warnings" export RUSTDOCFLAGS="-D warnings" run_tests() { for release in "" "--release"; do + cargo $1 test $release --no-default-features # Not very useful without std or hashbrown, but hey, it works! (Doctests emit an error about needing a global allocator, but it exits zero anyway. ¯\_(ツ)_/¯) cargo $1 test $release --no-default-features --features hashbrown - cargo $1 test $release --features hashbrown - # (2>/dev/null because otherwise you’ll keep seeing errors and double-guessing whether they were supposed to happen or whether the script failed to exit nonzero.) - ! 2>/dev/null cargo $1 test $release --no-default-features || ! echo "'cargo $1 test $release --no-default-features' failed to fail (sorry, its stderr is suppressed, try it manually)" cargo $1 test $release + cargo $1 test $release --all-features done }