std: Move the owned module from core to std

The compiler was updated to recognize that implementations for ty_uniq(..) are
allowed if the Box lang item is located in the current crate. This enforces the
idea that libcore cannot allocated, and moves all related trait implementations
from libcore to libstd.

This is a breaking change in that the AnyOwnExt trait has moved from the any
module to the owned module. Any previous users of std::any::AnyOwnExt should now
use std::owned::AnyOwnExt instead. This was done because the trait is intended
for Box traits and only Box traits.

[breaking-change]

src/libstd/owned.rs

@@ -0,0 +1,101 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Operations on unique pointer types
+
+use any::{Any, AnyRefExt};
+use clone::Clone;
+use cmp::{Eq, Ord, TotalEq, TotalOrd, Ordering};
+use default::Default;
+use intrinsics;
+use mem;
+use raw::TraitObject;
+use result::{Ok, Err, Result};
+
+/// A value that represents the global exchange heap. This is the default
+/// place that the `box` keyword allocates into when no place is supplied.
+///
+/// The following two examples are equivalent:
+///
+///     let foo = box(HEAP) Bar::new(...);
+///     let foo = box Bar::new(...);
+#[lang="exchange_heap"]
+pub static HEAP: () = ();
+
+/// A type that represents a uniquely-owned value.
+#[lang="owned_box"]
+pub struct Box<T>(*T);
+
+impl<T: Default> Default for Box<T> {
+    fn default() -> Box<T> { box Default::default() }
+}
+
+impl<T: Clone> Clone for Box<T> {
+    /// Return a copy of the owned box.
+    #[inline]
+    fn clone(&self) -> Box<T> { box {(**self).clone()} }
+
+    /// Perform copy-assignment from `source` by reusing the existing allocation.
+    #[inline]
+    fn clone_from(&mut self, source: &Box<T>) {
+        (**self).clone_from(&(**source));
+    }
+}
+
+// box pointers
+impl<T:Eq> Eq for Box<T> {
+    #[inline]
+    fn eq(&self, other: &Box<T>) -> bool { *(*self) == *(*other) }
+    #[inline]
+    fn ne(&self, other: &Box<T>) -> bool { *(*self) != *(*other) }
+}
+impl<T:Ord> Ord for Box<T> {
+    #[inline]
+    fn lt(&self, other: &Box<T>) -> bool { *(*self) < *(*other) }
+    #[inline]
+    fn le(&self, other: &Box<T>) -> bool { *(*self) <= *(*other) }
+    #[inline]
+    fn ge(&self, other: &Box<T>) -> bool { *(*self) >= *(*other) }
+    #[inline]
+    fn gt(&self, other: &Box<T>) -> bool { *(*self) > *(*other) }
+}
+impl<T: TotalOrd> TotalOrd for Box<T> {
+    #[inline]
+    fn cmp(&self, other: &Box<T>) -> Ordering { (**self).cmp(*other) }
+}
+impl<T: TotalEq> TotalEq for Box<T> {}
+
+/// Extension methods for an owning `Any` trait object
+pub trait AnyOwnExt {
+    /// Returns the boxed value if it is of type `T`, or
+    /// `Err(Self)` if it isn't.
+    fn move<T: 'static>(self) -> Result<Box<T>, Self>;
+}
+
+impl AnyOwnExt for Box<Any> {
+    #[inline]
+    fn move<T: 'static>(self) -> Result<Box<T>, Box<Any>> {
+        if self.is::<T>() {
+            unsafe {
+                // Get the raw representation of the trait object
+                let to: TraitObject =
+                    *mem::transmute::<&Box<Any>, &TraitObject>(&self);
+
+                // Prevent destructor on self being run
+                intrinsics::forget(self);
+
+                // Extract the data pointer
+                Ok(mem::transmute(to.data))
+            }
+        } else {
+            Err(self)
+        }
+    }
+}