X-Git-Url: https://git.chrismorgan.info/anymap/blobdiff_plain/512885e502985a30a5b64e881f6f3af5a901d301..016d324c51387842a3c9e67bd8c36f08f9496fd9:/src/lib.rs

diff --git a/src/lib.rs b/src/lib.rs
index 94410f0..7619367 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,197 +1,454 @@
 //! 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, unnecessary_typecast,
-        missing_doc, unused_result)]
+#![cfg_attr(all(feature = "bench", test), feature(test))]
+#![warn(missing_docs, unused_results)]
 
-#[cfg(test)]
+#[cfg(all(feature = "bench", 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::raw::TraitObject;
-
-struct TypeIdHasher;
+use std::any::TypeId;
+use std::marker::PhantomData;
 
-struct TypeIdState {
-    value: u64,
-}
+use raw::RawMap;
+use any::{UncheckedAnyExt, IntoBox, Any};
 
-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)
-        }
-    }
-}
+macro_rules! impl_common_methods {
+    (
+        field: $t:ident.$field:ident;
+        new() => $new:expr;
+        with_capacity($with_capacity_arg:ident) => $with_capacity:expr;
+    ) => {
+        impl<A: ?Sized + UncheckedAnyExt> $t<A> {
+            /// Create an empty collection.
+            #[inline]
+            pub fn new() -> $t<A> {
+                $t {
+                    $field: $new,
+                }
+            }
 
-impl Hasher<TypeIdState> for TypeIdHasher {
-    fn hash<T: Hash<TypeIdState>>(&self, value: &T) -> u64 {
-        let mut state = TypeIdState {
-            value: 0,
-        };
-        value.hash(&mut state);
-        state.value
-    }
-}
+            /// Creates an empty collection with the given initial capacity.
+            #[inline]
+            pub fn with_capacity($with_capacity_arg: usize) -> $t<A> {
+                $t {
+                    $field: $with_capacity,
+                }
+            }
 
-/// 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<T: 'static>(self) -> &'a T;
-}
+            /// Returns the number of elements the collection can hold without reallocating.
+            #[inline]
+            pub fn capacity(&self) -> usize {
+                self.$field.capacity()
+            }
 
-impl<'a> UncheckedAnyRefExt<'a> for &'a Any + 'a {
-    #[inline]
-    unsafe fn as_ref_unchecked<T: 'static>(self) -> &'a T {
-        // Get the raw representation of the trait object
-        let to: TraitObject = transmute_copy(&self);
+            /// 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.$field.reserve(additional)
+            }
 
-        // Extract the data pointer
-        transmute(to.data)
-    }
-}
+            /// 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.$field.shrink_to_fit()
+            }
 
-/// 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 as_mut_unchecked<T: 'static>(self) -> &'a mut T;
-}
+            /// Returns the number of items in the collection.
+            #[inline]
+            pub fn len(&self) -> usize {
+                self.$field.len()
+            }
 
-impl<'a> UncheckedAnyMutRefExt<'a> for &'a mut Any + 'a {
-    #[inline]
-    unsafe fn as_mut_unchecked<T: 'static>(self) -> &'a mut T {
-        // Get the raw representation of the trait object
-        let to: TraitObject = transmute_copy(&self);
+            /// Returns true if there are no items in the collection.
+            #[inline]
+            pub fn is_empty(&self) -> bool {
+                self.$field.is_empty()
+            }
 
-        // Extract the data pointer
-        transmute(to.data)
+            /// Removes all items from the collection. Keeps the allocated memory for reuse.
+            #[inline]
+            pub fn clear(&mut self) {
+                self.$field.clear()
+            }
+        }
     }
 }
 
-/// A map containing zero or one values for any given type and allowing convenient,
+pub mod any;
+pub mod raw;
+
+/// 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 `anymap::any::Any`, but there are other choices:
+///
+/// - If you want the entire map to be cloneable, use `CloneAny` instead of `Any`.
+/// - You can add on `+ Send` and/or `+ Sync` (e.g. `Map<Any + Send>`) to add those bounds.
+///
 /// ```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::<int>();
-/// assert_eq!(data.find::<int>(), None);
+/// assert_eq!(data.get(), None::<&i32>);
+/// data.insert(42i32);
+/// assert_eq!(data.get(), Some(&42i32));
+/// data.remove::<i32>();
+/// assert_eq!(data.get::<i32>(), None);
 ///
-/// #[deriving(PartialEq, Show)]
+/// #[derive(Clone, PartialEq, Debug)]
 /// struct Foo {
 ///     str: String,
 /// }
 ///
-/// assert_eq!(data.find::<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::<Foo>(), None);
+/// data.insert(Foo { str: format!("foo") });
+/// assert_eq!(data.get(), Some(&Foo { str: format!("foo") }));
+/// data.get_mut::<Foo>().map(|foo| foo.str.push('t'));
+/// assert_eq!(&*data.get::<Foo>().unwrap().str, "foot");
 /// ```
 ///
 /// Values containing non-static references are not permitted.
-pub struct AnyMap {
-    data: HashMap<TypeId, Box<Any + 'static>, TypeIdHasher>,
+#[derive(Debug)]
+pub struct Map<A: ?Sized + UncheckedAnyExt = Any> {
+    raw: RawMap<A>,
+}
+
+// #[derive(Clone)] would want A to implement Clone, but in reality it’s only Box<A> that can.
+impl<A: ?Sized + UncheckedAnyExt> Clone for Map<A> where Box<A>: Clone {
+    fn clone(&self) -> Map<A> {
+        Map {
+            raw: self.raw.clone(),
+        }
+    }
+}
+
+/// The most common type of `Map`: just using `Any`.
+///
+/// Why is this a separate type alias rather than a default value for `Map<A>`? `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<Any>;
+
+impl_common_methods! {
+    field: Map.raw;
+    new() => RawMap::new();
+    with_capacity(capacity) => RawMap::with_capacity(capacity);
 }
 
-impl AnyMap {
-    /// Construct a new `AnyMap`.
-    pub fn new() -> AnyMap {
-        AnyMap {
-            data: HashMap::with_hasher(TypeIdHasher),
+impl<A: ?Sized + UncheckedAnyExt> Map<A> {
+    /// Returns a reference to the value stored in the collection for the type `T`, if it exists.
+    pub fn get<T: IntoBox<A>>(&self) -> Option<&T> {
+        self.raw.get(&TypeId::of::<T>())
+            .map(|any| unsafe { any.downcast_ref_unchecked::<T>() })
+    }
+
+    /// Returns a mutable reference to the value stored in the collection for the type `T`,
+    /// if it exists.
+    pub fn get_mut<T: IntoBox<A>>(&mut self) -> Option<&mut T> {
+        self.raw.get_mut(&TypeId::of::<T>())
+            .map(|any| unsafe { any.downcast_mut_unchecked::<T>() })
+    }
+
+    /// 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<T: IntoBox<A>>(&mut self, value: T) -> Option<T> {
+        unsafe {
+            self.raw.insert(TypeId::of::<T>(), value.into_box())
+                .map(|any| *any.downcast_unchecked::<T>())
+        }
+    }
+
+    /// Removes the `T` value from the collection,
+    /// returning it if there was one or `None` if there was not.
+    pub fn remove<T: IntoBox<A>>(&mut self) -> Option<T> {
+        self.raw.remove(&TypeId::of::<T>())
+            .map(|any| *unsafe { any.downcast_unchecked::<T>() })
+    }
+
+    /// Returns true if the collection contains a value of type `T`.
+    #[inline]
+    pub fn contains<T: IntoBox<A>>(&self) -> bool {
+        self.raw.contains_key(&TypeId::of::<T>())
+    }
+
+    /// Gets the entry for the given type in the collection for in-place manipulation
+    pub fn entry<T: IntoBox<A>>(&mut self) -> Entry<A, T> {
+        match self.raw.entry(TypeId::of::<T>()) {
+            raw::Entry::Occupied(e) => Entry::Occupied(OccupiedEntry {
+                inner: e,
+                type_: PhantomData,
+            }),
+            raw::Entry::Vacant(e) => Entry::Vacant(VacantEntry {
+                inner: e,
+                type_: PhantomData,
+            }),
         }
     }
 }
 
-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::<T>()).map(|any| unsafe { any.as_ref_unchecked::<T>() })
+impl<A: ?Sized + UncheckedAnyExt> AsRef<RawMap<A>> for Map<A> {
+    fn as_ref(&self) -> &RawMap<A> {
+        &self.raw
     }
+}
 
-    /// 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>() })
+impl<A: ?Sized + UncheckedAnyExt> AsMut<RawMap<A>> for Map<A> {
+    fn as_mut(&mut self) -> &mut RawMap<A> {
+        &mut self.raw
     }
+}
 
-    /// 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>);
+impl<A: ?Sized + UncheckedAnyExt> Into<RawMap<A>> for Map<A> {
+    fn into(self) -> RawMap<A> {
+        self.raw
     }
+}
+
+/// A view into a single occupied location in an `Map`.
+pub struct OccupiedEntry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
+    inner: raw::OccupiedEntry<'a, A>,
+    type_: PhantomData<V>,
+}
 
-    /// Remove the value for the type `T` if it existed.
-    pub fn remove<T: 'static>(&mut self) {
-        self.data.remove(&TypeId::of::<T>());
+/// A view into a single empty location in an `Map`.
+pub struct VacantEntry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
+    inner: raw::VacantEntry<'a, A>,
+    type_: PhantomData<V>,
+}
+
+/// A view into a single location in an `Map`, which may be vacant or occupied.
+pub enum Entry<'a, A: ?Sized + UncheckedAnyExt, V: 'a> {
+    /// An occupied Entry
+    Occupied(OccupiedEntry<'a, A, V>),
+    /// A vacant Entry
+    Vacant(VacantEntry<'a, A, V>),
+}
+
+impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A> + Clone> 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.
+    pub fn or_insert(self, default: V) -> &'a mut V {
+        match self {
+            Entry::Occupied(inner) => inner.into_mut(),
+            Entry::Vacant(inner) => inner.insert(default),
+        }
     }
 
-    /// Does a value of type `T` exist?
-    pub fn contains<T: 'static>(&self) -> bool {
-        self.data.contains_key(&TypeId::of::<T>())
+    /// 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.
+    pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V {
+        match self {
+            Entry::Occupied(inner) => inner.into_mut(),
+            Entry::Vacant(inner) => inner.insert(default()),
+        }
     }
 }
 
-impl Collection for AnyMap {
-    fn len(&self) -> uint {
-        self.data.len()
+impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> OccupiedEntry<'a, A, V> {
+    /// Gets a reference to the value in the entry
+    pub fn get(&self) -> &V {
+        unsafe { self.inner.get().downcast_ref_unchecked() }
+    }
+
+    /// Gets a mutable reference to the value in the entry
+    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
+    pub fn into_mut(self) -> &'a mut V {
+        unsafe { self.inner.into_mut().downcast_mut_unchecked() }
     }
 
-    fn is_empty(&self) -> bool {
-        self.data.is_empty()
+    /// Sets the value of the entry, and returns the entry's old value
+    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
+    pub fn remove(self) -> V {
+        unsafe { *self.inner.remove().downcast_unchecked() }
     }
 }
 
-impl Mutable for AnyMap {
-    fn clear(&mut self) {
-        self.data.clear();
+impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> VacantEntry<'a, 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.inner.insert(value.into_box()).downcast_mut_unchecked() }
     }
 }
 
+#[cfg(feature = "bench")]
 #[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 0..100 {
+            let _ = data.insert(42);
         }
     })
 }
 
+#[cfg(feature = "bench")]
 #[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 0..100 {
+            assert_eq!(data.get(), None::<&i32>);
         }
     })
 }
 
+#[cfg(feature = "bench")]
 #[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(42);
         // 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 0..100 {
+            assert_eq!(data.get(), Some(&42));
         }
     })
 }
+
+#[cfg(test)]
+mod tests {
+    use {Map, AnyMap, Entry};
+    use any::{Any, CloneAny};
+
+    #[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);
+
+    #[test]
+    fn test_entry() {
+        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.insert(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::<B>().unwrap(), &B(200));
+        assert_eq!(map.len(), 6);
+
+
+        // Existing key (remove)
+        match map.entry::<C>() {
+            Entry::Vacant(_) => unreachable!(),
+            Entry::Occupied(view) => {
+                assert_eq!(view.remove(), 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.insert(J(1000)), J(1000));
+            }
+        }
+        assert_eq!(map.get::<J>().unwrap(), &J(1000));
+        assert_eq!(map.len(), 6);
+
+        // Entry.or_insert on existing key
+        map.entry::<B>().or_insert(B(71)).0 += 1;
+        assert_eq!(map.get::<B>().unwrap(), &B(201));
+        assert_eq!(map.len(), 6);
+
+        // Entry.or_insert on nonexisting key
+        map.entry::<C>().or_insert(C(300)).0 += 1;
+        assert_eq!(map.get::<C>().unwrap(), &C(301));
+        assert_eq!(map.len(), 7);
+    }
+
+    #[test]
+    fn test_clone() {
+        let mut map: Map<CloneAny> = 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::<A>(), Some(&A(1)));
+        assert_eq!(map2.get::<B>(), Some(&B(2)));
+        assert_eq!(map2.get::<C>(), None);
+        assert_eq!(map2.get::<D>(), Some(&D(3)));
+        assert_eq!(map2.get::<E>(), Some(&E(4)));
+        assert_eq!(map2.get::<F>(), Some(&F(5)));
+        assert_eq!(map2.get::<J>(), Some(&J(6)));
+    }
+
+    #[test]
+    fn test_varieties() {
+        fn assert_send<T: Send>() { }
+        fn assert_sync<T: Sync>() { }
+        fn assert_clone<T: Clone>() { }
+        fn assert_debug<T: ::std::fmt::Debug>() { }
+        assert_send::<Map<Any + Send>>();
+        assert_send::<Map<Any + Send + Sync>>();
+        assert_sync::<Map<Any + Sync>>();
+        assert_sync::<Map<Any + Send + Sync>>();
+        assert_debug::<Map<Any>>();
+        assert_debug::<Map<Any + Send>>();
+        assert_debug::<Map<Any + Sync>>();
+        assert_debug::<Map<Any + Send + Sync>>();
+        assert_send::<Map<CloneAny + Send>>();
+        assert_send::<Map<CloneAny + Send + Sync>>();
+        assert_sync::<Map<CloneAny + Sync>>();
+        assert_sync::<Map<CloneAny + Send + Sync>>();
+        assert_clone::<Map<CloneAny + Send>>();
+        assert_clone::<Map<CloneAny + Send + Sync>>();
+        assert_clone::<Map<CloneAny + Sync>>();
+        assert_clone::<Map<CloneAny + Send + Sync>>();
+        assert_debug::<Map<CloneAny>>();
+        assert_debug::<Map<CloneAny + Send>>();
+        assert_debug::<Map<CloneAny + Sync>>();
+        assert_debug::<Map<CloneAny + Send + Sync>>();
+    }
+}