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Rust update.

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This includes following the standard new semantics for `insert` and
`remove`, where they return any value that was previously present, and
renaming `find` and `find_mut` to `get` and `get_mut`. For the moment,
I’ve even provided a deprecation path! Will wonders ever cease?
This commit is contained in:
Chris Morgan 2014-11-08 10:24:37 +11:00
parent 10244cfbba
commit c29e78c563
1 changed files with 65 additions and 28 deletions
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93
src/lib.rs
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@ -11,7 +11,7 @@
extern crate test;
use std::any::Any;
use std::intrinsics::TypeId;
use std::intrinsics::{forget, TypeId};
use std::collections::HashMap;
use std::hash::{Hash, Hasher, Writer};
use std::mem::{transmute, transmute_copy};
@ -50,12 +50,12 @@ impl Hasher<TypeIdState> for TypeIdHasher {
trait UncheckedAnyRefExt<'a> {
/// Returns a reference to the boxed value, assuming that it is of type `T`. This should only be
/// called if you are ABSOLUTELY CERTAIN of `T` as you will get really wacky output if it’s not.
unsafe fn as_ref_unchecked<T: 'static>(self) -> &'a T;
unsafe fn downcast_ref_unchecked<T: 'static>(self) -> &'a T;
}
impl<'a> UncheckedAnyRefExt<'a> for &'a Any + 'a {
#[inline]
unsafe fn as_ref_unchecked<T: 'static>(self) -> &'a T {
unsafe fn downcast_ref_unchecked<T: 'static>(self) -> &'a T {
// Get the raw representation of the trait object
let to: TraitObject = transmute_copy(&self);
@ -68,12 +68,12 @@ impl<'a> UncheckedAnyRefExt<'a> for &'a Any + 'a {
trait UncheckedAnyMutRefExt<'a> {
/// Returns a reference to the boxed value, assuming that it is of type `T`. This should only be
/// called if you are ABSOLUTELY CERTAIN of `T` as you will get really wacky output if it’s not.
unsafe fn as_mut_unchecked<T: 'static>(self) -> &'a mut T;
unsafe fn downcast_mut_unchecked<T: 'static>(self) -> &'a mut T;
}
impl<'a> UncheckedAnyMutRefExt<'a> for &'a mut Any + 'a {
#[inline]
unsafe fn as_mut_unchecked<T: 'static>(self) -> &'a mut T {
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);
@ -82,28 +82,49 @@ impl<'a> UncheckedAnyMutRefExt<'a> for &'a mut Any + 'a {
}
}
/// 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('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.
@ -121,25 +142,41 @@ impl AnyMap {
}
impl AnyMap {
/// Retrieve the value stored in the map for the type `T`, if it exists.
/// Deprecated: Renamed to `get`.
#[deprecated = "Renamed to `get`"]
pub fn find<T: Any + 'static>(&self) -> Option<&T> {
self.data.find(&TypeId::of::<T>()).map(|any| unsafe { any.as_ref_unchecked::<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 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<T: Any + 'static>(&mut self) -> Option<&mut T> {
self.data.find_mut(&TypeId::of::<T>()).map(|any| unsafe { any.as_mut_unchecked::<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: Any + 'static>(&mut self, value: T) {
self.data.insert(TypeId::of::<T>(), box value as Box<Any>);
/// 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: Any + '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?
@ -168,29 +205,29 @@ fn bench_insertion(b: &mut ::test::Bencher) {
b.iter(|| {
let mut data = AnyMap::new();
for _ in range(0u, 100) {
data.insert(42i);
let _ = data.insert(42i);
}
})
}
#[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>);
assert_eq!(data.get(), None::<&int>);
}
})
}
#[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(42i);
// These inner loops are a feeble attempt to drown the other factors.
for _ in range(0u, 100) {
assert_eq!(data.find(), Some(&42i));
assert_eq!(data.get(), Some(&42i));
}
})
}