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// Copyright 2012-2013 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.
/*! The `Clone` trait for types that cannot be 'implicitly copied'
In Rust, some simple types are "implicitly copyable" and when you
assign them or pass them as arguments, the receiver will get a copy,
leaving the original value in place. These types do not require
allocation to copy and do not have finalizers (i.e. they do not
contain owned boxes or implement `Drop`), so the compiler considers
them cheap and safe to copy. For other types copies must be made
explicitly, by convention implementing the `Clone` trait and calling
the `clone` method.
*/
/// A common trait for cloning an object.
pub trait Clone {
/// Returns a copy of the value. The contents of owned pointers
/// are copied to maintain uniqueness, while the contents of
/// managed pointers are not copied.
fn clone(&self) -> Self;
/// Perform copy-assignment from `source`.
///
/// `a.clone_from(&b)` is equivalent to `a = b.clone()` in functionality,
/// but can be overridden to reuse the resources of `a` to avoid unnecessary
/// allocations.
#[inline(always)]
fn clone_from(&mut self, source: &Self) {
*self = source.clone()
}
}
impl<T: Clone> Clone for ~T {
/// Return a copy of the owned box.
#[inline]
fn clone(&self) -> ~T { ~(**self).clone() }
/// Perform copy-assignment from `source` by reusing the existing allocation.
fn clone_from(&mut self, source: &~T) {
**self = (**source).clone()
}
}
impl<T> Clone for @T {
/// Return a shallow copy of the managed box.
#[inline]
fn clone(&self) -> @T { *self }
}
impl<'a, T> Clone for &'a T {
/// Return a shallow copy of the reference.
#[inline]
fn clone(&self) -> &'a T { *self }
}
impl<'a, T> Clone for &'a [T] {
/// Return a shallow copy of the slice.
#[inline]
fn clone(&self) -> &'a [T] { *self }
}
impl<'a> Clone for &'a str {
/// Return a shallow copy of the slice.
#[inline]
fn clone(&self) -> &'a str { *self }
}
macro_rules! clone_impl(
($t:ty) => {
impl Clone for $t {
/// Return a deep copy of the value.
#[inline]
fn clone(&self) -> $t { *self }
}
}
)
clone_impl!(int)
clone_impl!(i8)
clone_impl!(i16)
clone_impl!(i32)
clone_impl!(i64)
clone_impl!(uint)
clone_impl!(u8)
clone_impl!(u16)
clone_impl!(u32)
clone_impl!(u64)
clone_impl!(f32)
clone_impl!(f64)
clone_impl!(())
clone_impl!(bool)
clone_impl!(char)
macro_rules! extern_fn_clone(
($($A:ident),*) => (
impl<$($A,)* ReturnType> Clone for extern "Rust" fn($($A),*) -> ReturnType {
/// Return a copy of a function pointer
#[inline]
fn clone(&self) -> extern "Rust" fn($($A),*) -> ReturnType { *self }
}
)
)
extern_fn_clone!()
extern_fn_clone!(A)
extern_fn_clone!(A, B)
extern_fn_clone!(A, B, C)
extern_fn_clone!(A, B, C, D)
extern_fn_clone!(A, B, C, D, E)
extern_fn_clone!(A, B, C, D, E, F)
extern_fn_clone!(A, B, C, D, E, F, G)
extern_fn_clone!(A, B, C, D, E, F, G, H)
#[test]
fn test_owned_clone() {
let a = ~5i;
let b: ~int = a.clone();
assert_eq!(a, b);
}
#[test]
fn test_managed_clone() {
let a = @5i;
let b: @int = a.clone();
assert_eq!(a, b);
}
#[test]
fn test_borrowed_clone() {
let x = 5i;
let y: &int = &x;
let z: &int = (&y).clone();
assert_eq!(*z, 5);
}
#[test]
fn test_clone_from() {
let a = ~5;
let mut b = ~10;
b.clone_from(&a);
assert_eq!(*b, 5);
}
#[test]
fn test_extern_fn_clone() {
trait Empty {}
impl Empty for int {}
fn test_fn_a() -> f64 { 1.0 }
fn test_fn_b<T: Empty>(x: T) -> T { x }
fn test_fn_c(_: int, _: f64, _: ~[int], _: int, _: int, _: int) {}
let _ = test_fn_a.clone();
let _ = test_fn_b::<int>.clone();
let _ = test_fn_c.clone();
}
|
