anymap/
any.rs

1//! The different types of `Any` for use in a map.
2//!
3//! This stuff is all based on `std::any`, but goes a little further, with `CloneAny` being a
4//! cloneable `Any` and with the `Send` and `Sync` bounds possible on both `Any` and `CloneAny`.
5
6use std::fmt;
7use std::any::Any as StdAny;
8
9#[doc(hidden)]
10pub trait CloneToAny {
11    /// Clone `self` into a new `Box<CloneAny>` object.
12    fn clone_to_any(&self) -> Box<CloneAny>;
13
14    /// Clone `self` into a new `Box<CloneAny + Send>` object.
15    fn clone_to_any_send(&self) -> Box<CloneAny + Send> where Self: Send;
16
17    /// Clone `self` into a new `Box<CloneAny + Sync>` object.
18    fn clone_to_any_sync(&self) -> Box<CloneAny + Sync> where Self: Sync;
19
20    /// Clone `self` into a new `Box<CloneAny + Send + Sync>` object.
21    fn clone_to_any_send_sync(&self) -> Box<CloneAny + Send + Sync> where Self: Send + Sync;
22}
23
24impl<T: Any + Clone> CloneToAny for T {
25    #[inline]
26    fn clone_to_any(&self) -> Box<CloneAny> {
27        Box::new(self.clone())
28    }
29
30    #[inline]
31    fn clone_to_any_send(&self) -> Box<CloneAny + Send> where Self: Send {
32        Box::new(self.clone())
33    }
34
35    #[inline]
36    fn clone_to_any_sync(&self) -> Box<CloneAny + Sync> where Self: Sync {
37        Box::new(self.clone())
38    }
39
40    #[inline]
41    fn clone_to_any_send_sync(&self) -> Box<CloneAny + Send + Sync> where Self: Send + Sync {
42        Box::new(self.clone())
43    }
44}
45
46macro_rules! define {
47    (CloneAny) => {
48        /// A type to emulate dynamic typing.
49        ///
50        /// Every type with no non-`'static` references implements `Any`.
51        define!(CloneAny remainder);
52    };
53    (Any) => {
54        /// A type to emulate dynamic typing with cloning.
55        ///
56        /// Every type with no non-`'static` references that implements `Clone` implements `Any`.
57        define!(Any remainder);
58    };
59    ($t:ident remainder) => {
60        /// See the [`std::any` documentation](https://doc.rust-lang.org/std/any/index.html) for
61        /// more details on `Any` in general.
62        ///
63        /// This trait is not `std::any::Any` but rather a type extending that for this library’s
64        /// purposes so that it can be combined with marker traits like 
65        /// <code><a class=trait title=core::marker::Send
66        /// href=http://doc.rust-lang.org/std/marker/trait.Send.html>Send</a></code> and
67        /// <code><a class=trait title=core::marker::Sync
68        /// href=http://doc.rust-lang.org/std/marker/trait.Sync.html>Sync</a></code>.
69        ///
70        define!($t trait);
71    };
72    (CloneAny trait) => {
73        /// See also [`Any`](trait.Any.html) for a version without the `Clone` requirement.
74        pub trait CloneAny: Any + CloneToAny { }
75        impl<T: StdAny + Clone> CloneAny for T { }
76    };
77    (Any trait) => {
78        /// See also [`CloneAny`](trait.CloneAny.html) for a cloneable version of this trait.
79        pub trait Any: StdAny { }
80        impl<T: StdAny> Any for T { }
81    };
82}
83
84macro_rules! impl_clone {
85    ($t:ty, $method:ident) => {
86        impl Clone for Box<$t> {
87            #[inline]
88            fn clone(&self) -> Box<$t> {
89                (**self).$method()
90            }
91        }
92    }
93}
94
95#[allow(missing_docs)]  // Bogus warning (it’s not public outside the crate), ☹
96pub trait UncheckedAnyExt: Any {
97    unsafe fn downcast_ref_unchecked<T: Any>(&self) -> &T;
98    unsafe fn downcast_mut_unchecked<T: Any>(&mut self) -> &mut T;
99    unsafe fn downcast_unchecked<T: Any>(self: Box<Self>) -> Box<T>;
100}
101
102#[doc(hidden)]
103/// A trait for the conversion of an object into a boxed trait object.
104pub trait IntoBox<A: ?Sized + UncheckedAnyExt>: Any {
105    /// Convert self into the appropriate boxed form.
106    fn into_box(self) -> Box<A>;
107}
108
109macro_rules! implement {
110    ($base:ident, $(+ $bounds:ident)*) => {
111        impl fmt::Debug for $base $(+ $bounds)* {
112            #[inline]
113            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
114                f.pad(stringify!($base $(+ $bounds)*))
115            }
116        }
117
118        impl UncheckedAnyExt for $base $(+ $bounds)* {
119            #[inline]
120            unsafe fn downcast_ref_unchecked<T: 'static>(&self) -> &T {
121                &*(self as *const Self as *const T)
122            }
123
124            #[inline]
125            unsafe fn downcast_mut_unchecked<T: 'static>(&mut self) -> &mut T {
126                &mut *(self as *mut Self as *mut T)
127            }
128
129            #[inline]
130            unsafe fn downcast_unchecked<T: 'static>(self: Box<Self>) -> Box<T> {
131                Box::from_raw(Box::into_raw(self) as *mut T)
132            }
133        }
134
135        impl<T: $base $(+ $bounds)*> IntoBox<$base $(+ $bounds)*> for T {
136            #[inline]
137            fn into_box(self) -> Box<$base $(+ $bounds)*> {
138                Box::new(self)
139            }
140        }
141    }
142}
143
144define!(Any);
145implement!(Any,);
146implement!(Any, + Send);
147implement!(Any, + Sync);
148implement!(Any, + Send + Sync);
149implement!(CloneAny,);
150implement!(CloneAny, + Send);
151implement!(CloneAny, + Sync);
152implement!(CloneAny, + Send + Sync);
153
154define!(CloneAny);
155impl_clone!(CloneAny, clone_to_any);
156impl_clone!((CloneAny + Send), clone_to_any_send);
157impl_clone!((CloneAny + Sync), clone_to_any_sync);
158impl_clone!((CloneAny + Send + Sync), clone_to_any_send_sync);
anymap/any.rs

anymap/
any.rs
