X-Git-Url: https://git.chrismorgan.info/anymap/blobdiff_plain/2e37f0d1aebbd0c56acd0de7b46d14cd71d3e134..deb7daf170b608a1d7965c702d340249bfe22bbd:/src/lib.rs diff --git a/src/lib.rs b/src/lib.rs index 0c71e36..a6f0e46 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -1,63 +1,64 @@ //! This crate provides the `AnyMap` type, a safe and convenient store for one value of each type. -#![crate_name = "anymap"] -#![crate_type = "lib"] -#![feature(default_type_params)] -#![warn(unnecessary_qualification, non_uppercase_statics, - variant_size_difference, managed_heap_memory, unnecessary_typecast, - missing_doc, unused_result)] +#![feature(core, std_misc, hash)] +#![cfg_attr(test, feature(test))] +#![warn(unused_qualifications, non_upper_case_globals, + variant_size_differences, unused_typecasts, + missing_docs, unused_results)] #[cfg(test)] extern crate test; -use std::any::Any; -use std::intrinsics::TypeId; -use std::collections::{Collection, HashMap, Mutable}; -use std::hash::{Hash, Hasher, Writer}; -use std::mem::{transmute, transmute_copy}; +use std::any::{Any, TypeId}; +use std::mem::forget; +use std::collections::HashMap; +use std::collections::hash_map; +use std::hash::Hasher; +use std::collections::hash_state::HashState; +use std::mem::transmute; use std::raw::TraitObject; +use std::marker::PhantomData; -struct TypeIdHasher; - -struct TypeIdState { +struct TypeIdHasher { value: u64, } -impl Writer for TypeIdState { +struct TypeIdState; + +impl HashState for TypeIdState { + type Hasher = TypeIdHasher; + + fn hasher(&self) -> TypeIdHasher { + TypeIdHasher { value: 0 } + } +} + +impl Hasher for TypeIdHasher { #[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) + std::ptr::copy_nonoverlapping(&mut self.value, transmute(&bytes[0]), 1) } } -} -impl Hasher for TypeIdHasher { - fn hash>(&self, value: &T) -> u64 { - let mut state = TypeIdState { - value: 0, - }; - value.hash(&mut state); - state.value - } + #[inline(always)] + fn finish(&self) -> u64 { self.value } } /// 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(self) -> &'a T; + unsafe fn downcast_ref_unchecked(self) -> &'a T; } impl<'a> UncheckedAnyRefExt<'a> for &'a Any { #[inline] - unsafe fn as_ref_unchecked(self) -> &'a T { + unsafe fn downcast_ref_unchecked(self) -> &'a T { // Get the raw representation of the trait object - let to: TraitObject = transmute_copy(&self); + let to: TraitObject = transmute(self); // Extract the data pointer transmute(to.data) @@ -68,130 +69,454 @@ impl<'a> UncheckedAnyRefExt<'a> for &'a Any { 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(self) -> &'a mut T; + unsafe fn downcast_mut_unchecked(self) -> &'a mut T; } impl<'a> UncheckedAnyMutRefExt<'a> for &'a mut Any { #[inline] - unsafe fn as_mut_unchecked(self) -> &'a mut T { + unsafe fn downcast_mut_unchecked(self) -> &'a mut T { // Get the raw representation of the trait object - let to: TraitObject = transmute_copy(&self); + let to: TraitObject = transmute(self); // Extract the data pointer transmute(to.data) } } -/// A map containing zero or one values for any given type and allowing convenient, +/// An extension of `BoxAny` allowing unchecked downcasting of trait objects to `Box`. +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(self) -> Box; +} + +impl UncheckedBoxAny for Box { + #[inline] + unsafe fn downcast_unchecked(self) -> Box { + // Get the raw representation of the trait object + let to: TraitObject = *transmute::<&Box, &TraitObject>(&self); + + // Prevent destructor on self being run + forget(self); + + // Extract the data pointer + transmute(to.data) + } +} + +/// A collection containing zero or one values for any given type and allowing convenient, /// type-safe access to those values. /// /// ```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::(); -/// assert_eq!(data.find::(), None); +/// assert_eq!(data.get(), None::<&i32>); +/// data.insert(42i32); +/// assert_eq!(data.get(), Some(&42i32)); +/// data.remove::(); +/// assert_eq!(data.get::(), None); /// -/// #[deriving(PartialEq, Show)] +/// #[derive(PartialEq, Debug)] /// struct Foo { /// str: String, /// } /// -/// assert_eq!(data.find::(), None); -/// data.insert(Foo { str: "foo".to_string() }); -/// assert_eq!(data.find(), Some(&Foo { str: "foo".to_string() })); -/// data.find_mut::().map(|foo| foo.str.push_char('t')); -/// assert_eq!(data.find::().unwrap().str.as_slice(), "foot"); +/// 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. pub struct AnyMap { - data: HashMap, TypeIdHasher>, + data: HashMap, TypeIdState>, } impl AnyMap { /// Construct a new `AnyMap`. + #[inline] pub fn new() -> AnyMap { AnyMap { - data: HashMap::with_hasher(TypeIdHasher), + data: HashMap::with_hash_state(TypeIdState), } } -} -impl AnyMap { - /// Retrieve the value stored in the map for the type `T`, if it exists. - pub fn find<'a, T: 'static>(&'a self) -> Option<&'a T> { - self.data.find(&TypeId::of::()).map(|any| unsafe { any.as_ref_unchecked::() }) + /// Creates an empty AnyMap with the given initial capacity. + #[inline] + pub fn with_capcity(capacity: usize) -> AnyMap { + AnyMap { + data: HashMap::with_capacity_and_hash_state(capacity, TypeIdState), + } + } + + /// Returns the number of elements the collection can hold without reallocating. + #[inline] + pub fn capacity(&self) -> usize { + self.data.capacity() + } + + /// Reserves capacity for at least `additional` more elements to be inserted + /// in the `AnyMap`. 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.data.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.data.shrink_to_fit() } - /// Retrieve a mutable reference to the value stored in the map for the type `T`, if it exists. - pub fn find_mut<'a, T: 'static>(&'a mut self) -> Option<&'a mut T> { - self.data.find_mut(&TypeId::of::()).map(|any| unsafe { any.as_mut_unchecked::() }) + /// An iterator visiting all items in the collection in arbitrary order. + /// Iterator element type is `&Any`. + /// + /// This is probably not a great deal of use. + #[inline] + pub fn iter(&self) -> Iter { + Iter { + inner: self.data.iter(), + } + } + + /// An iterator visiting all items in the collection in arbitrary order. + /// Iterator element type is `&mut Any`. + /// + /// This is probably not a great deal of use. + #[inline] + pub fn iter_mut(&mut self) -> IterMut { + IterMut { + inner: self.data.iter_mut(), + } + } + + /// An iterator visiting all items in the collection in arbitrary order. + /// Creates a consuming iterator, that is, one that moves each item + /// out of the map in arbitrary order. The map cannot be used after + /// calling this. + /// + /// Iterator element type is `Box`. + #[inline] + pub fn into_iter(self) -> IntoIter { + IntoIter { + inner: self.data.into_iter(), + } + } + + /// Returns a reference to the value stored in the collection for the type `T`, if it exists. + pub fn get(&self) -> Option<&T> { + self.data.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. + pub fn get_mut(&mut self) -> Option<&mut T> { + self.data.get_mut(&TypeId::of::()) + .map(|any| unsafe { any.downcast_mut_unchecked::() }) } - /// Set the value contained in the map for the type `T`. - /// This will override any previous value stored. - pub fn insert(&mut self, value: T) { - self.data.insert(TypeId::of::(), box value as Box); + /// 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. + pub fn insert(&mut self, value: T) -> Option { + self.data.insert(TypeId::of::(), Box::new(value) as Box) + .map(|any| *unsafe { any.downcast_unchecked::() }) } - /// Remove the value for the type `T` if it existed. - pub fn remove(&mut self) { - self.data.remove(&TypeId::of::()); + /// Removes the `T` value from the collection, + /// returning it if there was one or `None` if there was not. + pub fn remove(&mut self) -> Option { + self.data.remove(&TypeId::of::()) + .map(|any| *unsafe { any.downcast_unchecked::() }) } - /// Does a value of type `T` exist? - pub fn contains(&self) -> bool { + /// Returns true if the collection contains a value of type `T`. + pub fn contains(&self) -> bool { self.data.contains_key(&TypeId::of::()) } -} -impl Collection for AnyMap { - fn len(&self) -> uint { + /// Gets the entry for the given type in the collection for in-place manipulation + pub fn entry(&mut self) -> Entry { + match self.data.entry(TypeId::of::()) { + hash_map::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry { + entry: e, + type_: PhantomData, + }), + hash_map::Entry::Vacant(e) => Entry::Vacant(VacantEntry { + entry: e, + type_: PhantomData, + }), + } + } + + /// Returns the number of items in the collection. + #[inline] + pub fn len(&self) -> usize { self.data.len() } - fn is_empty(&self) -> bool { + /// Returns true if there are no items in the collection. + #[inline] + pub fn is_empty(&self) -> bool { self.data.is_empty() } -} -impl Mutable for AnyMap { - fn clear(&mut self) { + /// Clears the map, returning all items as an iterator. + /// + /// Iterator element type is `Box`. + /// + /// Keeps the allocated memory for reuse. + #[inline] + pub fn drain(&mut self) -> Drain { + Drain { + inner: self.data.drain(), + } + } + + /// Removes all items from the collection. Keeps the allocated memory for reuse. + #[inline] + pub fn clear(&mut self) { self.data.clear(); } } +/// A view into a single occupied location in an AnyMap +pub struct OccupiedEntry<'a, V: 'a> { + entry: hash_map::OccupiedEntry<'a, TypeId, Box>, + type_: PhantomData, +} + +/// A view into a single empty location in an AnyMap +pub struct VacantEntry<'a, V: 'a> { + entry: hash_map::VacantEntry<'a, TypeId, Box>, + type_: PhantomData, +} + +/// A view into a single location in an AnyMap, which may be vacant or occupied +pub enum Entry<'a, V: 'a> { + /// An occupied Entry + Occupied(OccupiedEntry<'a, V>), + /// A vacant Entry + Vacant(VacantEntry<'a, V>), +} + +impl<'a, V: 'static + Clone> Entry<'a, V> { + /// Returns a mutable reference to the entry if occupied, or the VacantEntry if vacant + pub fn get(self) -> Result<&'a mut V, VacantEntry<'a, V>> { + match self { + Entry::Occupied(entry) => Ok(entry.into_mut()), + Entry::Vacant(entry) => Err(entry), + } + } +} + +impl<'a, V: 'static> OccupiedEntry<'a, V> { + /// Gets a reference to the value in the entry + pub fn get(&self) -> &V { + unsafe { self.entry.get().downcast_ref_unchecked() } + } + + /// Gets a mutable reference to the value in the entry + pub fn get_mut(&mut self) -> &mut V { + unsafe { self.entry.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 + pub fn into_mut(self) -> &'a mut V { + unsafe { self.entry.into_mut().downcast_mut_unchecked() } + } + + /// Sets the value of the entry, and returns the entry's old value + pub fn insert(&mut self, value: V) -> V { + unsafe { *self.entry.insert(Box::new(value) as Box).downcast_unchecked() } + } + + /// Takes the value out of the entry, and returns it + pub fn remove(self) -> V { + unsafe { *self.entry.remove().downcast_unchecked() } + } +} + +impl<'a, V: 'static> VacantEntry<'a, V> { + /// Sets the value of the entry with the VacantEntry's key, + /// and returns a mutable reference to it + pub fn insert(self, value: V) -> &'a mut V { + unsafe { self.entry.insert(Box::new(value) as Box).downcast_mut_unchecked() } + } +} + +/// `AnyMap` iterator. +#[derive(Clone)] +pub struct Iter<'a> { + inner: hash_map::Iter<'a, TypeId, Box>, +} + +/// `AnyMap` mutable references iterator. +pub struct IterMut<'a> { + inner: hash_map::IterMut<'a, TypeId, Box>, +} + +/// `AnyMap` draining iterator. +pub struct Drain<'a> { + inner: hash_map::Drain<'a, TypeId, Box>, +} + +/// `AnyMap` move iterator. +pub struct IntoIter { + inner: hash_map::IntoIter>, +} + +impl<'a> Iterator for Iter<'a> { + type Item = &'a Any; + + #[inline] + fn next(&mut self) -> Option<&'a Any> { + self.inner.next().map(|item| &**item.1) + } + + #[inline] + fn size_hint(&self) -> (usize, Option) { self.inner.size_hint() } +} + +impl<'a> Iterator for IterMut<'a> { + type Item = &'a mut Any; + + #[inline] + fn next(&mut self) -> Option<&'a mut Any> { + self.inner.next().map(|item| &mut **item.1) + } + + #[inline] + fn size_hint(&self) -> (usize, Option) { self.inner.size_hint() } +} + +impl<'a> Iterator for Drain<'a> { + type Item = Box; + + #[inline] + fn next(&mut self) -> Option> { + self.inner.next().map(|item| item.1) + } + + #[inline] + fn size_hint(&self) -> (usize, Option) { self.inner.size_hint() } +} + +impl Iterator for IntoIter { + type Item = Box; + + #[inline] + fn next(&mut self) -> Option> { + self.inner.next().map(|item| item.1) + } + + #[inline] + fn size_hint(&self) -> (usize, Option) { self.inner.size_hint() } +} + #[bench] fn bench_insertion(b: &mut ::test::Bencher) { b.iter(|| { let mut data = AnyMap::new(); - for _ in range(0u, 100) { - data.insert(42i); + for _ in range(0, 100) { + let _ = data.insert(42i32); } }) } #[bench] -fn bench_find_missing(b: &mut ::test::Bencher) { +fn bench_get_missing(b: &mut ::test::Bencher) { b.iter(|| { let data = AnyMap::new(); - for _ in range(0u, 100) { - assert_eq!(data.find(), None::<&int>); + for _ in range(0, 100) { + assert_eq!(data.get(), None::<&i32>); } }) } #[bench] -fn bench_find_present(b: &mut ::test::Bencher) { +fn bench_get_present(b: &mut ::test::Bencher) { b.iter(|| { let mut data = AnyMap::new(); - data.insert(42i); + let _ = data.insert(42i32); // These inner loops are a feeble attempt to drown the other factors. - for _ in range(0u, 100) { - assert_eq!(data.find(), Some(&42i)); + for _ in range(0, 100) { + assert_eq!(data.get(), Some(&42i32)); } }) } + +#[test] +fn test_entry() { + #[derive(Debug, PartialEq)] struct A(i32); + #[derive(Debug, PartialEq)] struct B(i32); + #[derive(Debug, PartialEq)] struct C(i32); + #[derive(Debug, PartialEq)] struct D(i32); + #[derive(Debug, PartialEq)] struct E(i32); + #[derive(Debug, PartialEq)] struct F(i32); + #[derive(Debug, PartialEq)] struct J(i32); + + 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::() { + 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); +}