//! This crate provides the `AnyMap` type, a safe and convenient store for one value of each type.
-#![crate_id = "anymap#0.9"]
-#![crate_type = "rlib"]
-#![crate_type = "dylib"]
-#![warn(unnecessary_qualification, non_uppercase_statics, unsafe_block,
- variant_size_difference, managed_heap_memory, unnecessary_typecast,
- missing_doc, unused_result, deprecated_owned_vector)]
-
-use std::any::{Any, AnyRefExt, AnyMutRefExt};
-use std::intrinsics::TypeId;
+#![feature(default_type_params)]
+#![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::{forget, TypeId};
use std::collections::HashMap;
+use std::collections::hash_map;
+use std::hash::{Hash, Hasher, Writer};
+use std::mem::transmute;
+use std::raw::TraitObject;
+
+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)
+ }
+ }
+}
+
+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
+ }
+}
+
+/// 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;
+}
+
+impl<'a> UncheckedAnyRefExt<'a> for &'a Any {
+ #[inline]
+ unsafe fn downcast_ref_unchecked<T: 'static>(self) -> &'a T {
+ // Get the raw representation of the trait object
+ let to: TraitObject = transmute(self);
+
+ // Extract the data pointer
+ transmute(to.data)
+ }
+}
+
+/// 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 {
+ #[inline]
+ unsafe fn downcast_mut_unchecked<T: 'static>(self) -> &'a mut T {
+ // Get the raw representation of the trait object
+ let to: TraitObject = transmute(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>;
+}
+
+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);
+
+ // Prevent destructor on self being run
+ forget(self);
+
+ // Extract the data pointer
+ transmute(to.data)
+ }
+}
/// A map 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>);
+/// assert_eq!(data.get(), None::<&int>);
/// data.insert(42i);
-/// assert_eq!(data.find(), Some(&42i));
+/// assert_eq!(data.get(), Some(&42i));
/// data.remove::<int>();
-/// assert_eq!(data.find::<int>(), None);
+/// assert_eq!(data.get::<int>(), None);
///
/// #[deriving(PartialEq, Show)]
/// struct Foo {
/// str: String,
/// }
///
-/// assert_eq!(data.find::<Foo>(), None);
+/// assert_eq!(data.get::<Foo>(), None);
/// data.insert(Foo { str: "foo".to_string() });
-/// assert_eq!(data.find(), Some(&Foo { str: "foo".to_string() }));
-/// data.find_mut::<Foo>().map(|foo| foo.str.push_char('t'));
-/// assert_eq!(data.find::<Foo>().unwrap().str.as_slice(), "foot");
+/// assert_eq!(data.get(), Some(&Foo { str: "foo".to_string() }));
+/// data.get_mut::<Foo>().map(|foo| foo.str.push('t'));
+/// assert_eq!(data.get::<Foo>().unwrap().str.as_slice(), "foot");
/// ```
///
/// Values containing non-static references are not permitted.
pub struct AnyMap {
- data: HashMap<TypeId, Box<Any>:'static>,
+ data: HashMap<TypeId, Box<Any + 'static>, TypeIdHasher>,
}
impl AnyMap {
/// Construct a new `AnyMap`.
pub fn new() -> AnyMap {
AnyMap {
- data: HashMap::new(),
+ data: HashMap::with_hasher(TypeIdHasher),
}
}
}
impl AnyMap {
+ /// Deprecated: Renamed to `get`.
+ #[deprecated = "Renamed to `get`"]
+ pub fn find<T: Any + 'static>(&self) -> Option<&T> {
+ self.get::<T>()
+ }
+
+ /// 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>()
+ }
+
/// 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::<T>()).and_then(|any| any.as_ref::<T>())
+ pub fn get<T: Any + 'static>(&self) -> Option<&T> {
+ self.data.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 find_mut<'a, T: 'static>(&'a mut self) -> Option<&'a mut T> {
- self.data.find_mut(&TypeId::of::<T>()).and_then(|any| any.as_mut::<T>())
+ pub fn get_mut<T: Any + 'static>(&mut self) -> Option<&mut T> {
+ self.data.get_mut(&TypeId::of::<T>())
+ .map(|any| unsafe { any.downcast_mut_unchecked::<T>() })
}
/// Set the value contained in the map for the type `T`.
- /// This will override any previous value stored.
- pub fn insert<T: 'static>(&mut self, value: T) {
- self.data.insert(TypeId::of::<T>(), box value as Box<Any>:'static);
+ /// 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>() })
}
- /// Remove the value for the type `T` if it existed.
- pub fn remove<T: 'static>(&mut self) {
- self.data.remove(&TypeId::of::<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>())
+ .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>())
+ }
+
+ /// 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::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry { entry: e }),
+ hash_map::Entry::Vacant(e) => Entry::Vacant(VacantEntry { entry: e }),
+ }
+ }
+
+ /// Returns the number of items in the collection.
+ pub fn len(&self) -> uint {
+ self.data.len()
+ }
+
+ /// Returns true if there are no items in the collection.
+ pub fn is_empty(&self) -> bool {
+ self.data.is_empty()
+ }
+
+ /// Removes all items from the collection.
+ 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<Any + 'static>>,
+}
+
+/// A view into a single empty location in an AnyMap
+pub struct VacantEntry<'a, V: 'a> {
+ entry: hash_map::VacantEntry<'a, TypeId, Box<Any + 'static>>,
+}
+
+/// A view into a single location in a map, 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> 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 map 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 set(&mut self, value: V) -> V {
+ unsafe { *self.entry.set(box value as Box<Any + 'static>).downcast_unchecked() }
+ }
+
+ /// Takes the value out of the entry, and returns it
+ pub fn take(self) -> V {
+ unsafe { *self.entry.take().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 set(self, value: V) -> &'a mut V {
+ unsafe { self.entry.set(box value as Box<Any + 'static>).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);
+ }
+ })
+}
+
+#[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>);
+ }
+ })
+}
+
+#[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));
+ }
+ })
+}
+
+#[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>() {
+ Entry::Vacant(_) => unreachable!(),
+ Entry::Occupied(mut view) => {
+ assert_eq!(view.get(), &A(10));
+ assert_eq!(view.set(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().unwrap(), &B(200));
+ assert_eq!(map.len(), 6);
+
+
+ // Existing key (take)
+ match map.entry::<C>() {
+ Entry::Vacant(_) => unreachable!(),
+ Entry::Occupied(view) => {
+ assert_eq!(view.take(), 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.set(J(1000)), J(1000));
+ }
}
+ assert_eq!(map.get::<J>().unwrap(), &J(1000));
+ assert_eq!(map.len(), 6);
}