X-Git-Url: https://git.chrismorgan.info/anymap/blobdiff_plain/183e9ff248661db509a4196bdd586e3a78bae0c9..f1710353a039c1d5e95d15bb54effd7cab8e047f:/src/lib.rs

diff --git a/src/lib.rs b/src/lib.rs
index 0a1a692..0e92822 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,20 +1,19 @@
 //! 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)]
+#![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::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::mem::transmute;
 use std::raw::TraitObject;
 
 struct TypeIdHasher;
@@ -37,7 +36,7 @@ impl Writer for TypeIdState {
 }
 
 impl Hasher<TypeIdState> for TypeIdHasher {
-    fn hash<T: Hash<TypeIdState>>(&self, value: &T) -> u64 {
+    fn hash<Sized? T: Hash<TypeIdState>>(&self, value: &T) -> u64 {
         let mut state = TypeIdState {
             value: 0,
         };
@@ -50,14 +49,14 @@ 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 {
+impl<'a> UncheckedAnyRefExt<'a> for &'a Any {
     #[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);
+        let to: TraitObject = transmute(self);
 
         // Extract the data pointer
         transmute(to.data)
@@ -68,14 +67,35 @@ 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 {
+impl<'a> UncheckedAnyMutRefExt<'a> for &'a mut Any {
     #[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);
+        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)
@@ -88,22 +108,22 @@ impl<'a> UncheckedAnyMutRefExt<'a> for &'a mut Any + 'a {
 /// ```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.
@@ -121,77 +141,219 @@ impl AnyMap {
 }
 
 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>()).map(|any| unsafe { any.as_ref_unchecked::<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>()).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: '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: '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: 'static>(&self) -> bool {
+    pub fn contains<T: Any + 'static>(&self) -> bool {
         self.data.contains_key(&TypeId::of::<T>())
     }
-}
 
-impl Collection for AnyMap {
-    fn len(&self) -> uint {
+    /// 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()
     }
 
-    fn is_empty(&self) -> bool {
+    /// Returns true if there are no items in the collection.
+    pub fn is_empty(&self) -> bool {
         self.data.is_empty()
     }
-}
 
-impl Mutable for AnyMap {
-    fn clear(&mut self) {
+    /// 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) {
-            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));
         }
     })
 }
+
+#[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);
+}