111 lines
3.0 KiB
Rust
111 lines
3.0 KiB
Rust
// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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/*! The `Clone` trait for types that cannot be 'implicitly copied'
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In Rust, some simple types are "implicitly copyable" and when you
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assign them or pass them as arguments, the receiver will get a copy,
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leaving the original value in place. These types do not require
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allocation to copy and do not have finalizers (i.e. they do not
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contain owned boxes or implement `Drop`), so the compiler considers
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them cheap and safe to copy. For other types copies must be made
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explicitly, by convention implementing the `Clone` trait and calling
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the `clone` method.
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*/
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#![unstable]
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/// A common trait for cloning an object.
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pub trait Clone {
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/// Returns a copy of the value.
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fn clone(&self) -> Self;
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/// Perform copy-assignment from `source`.
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///
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/// `a.clone_from(&b)` is equivalent to `a = b.clone()` in functionality,
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/// but can be overridden to reuse the resources of `a` to avoid unnecessary
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/// allocations.
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#[inline(always)]
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#[experimental = "this function is mostly unused"]
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fn clone_from(&mut self, source: &Self) {
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*self = source.clone()
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}
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}
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impl<'a, T> Clone for &'a T {
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/// Return a shallow copy of the reference.
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#[inline]
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fn clone(&self) -> &'a T { *self }
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}
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impl<'a, T> Clone for &'a [T] {
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/// Return a shallow copy of the slice.
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#[inline]
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fn clone(&self) -> &'a [T] { *self }
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}
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impl<'a> Clone for &'a str {
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/// Return a shallow copy of the slice.
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#[inline]
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fn clone(&self) -> &'a str { *self }
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}
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macro_rules! clone_impl(
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($t:ty) => {
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impl Clone for $t {
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/// Return a deep copy of the value.
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#[inline]
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fn clone(&self) -> $t { *self }
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}
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}
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)
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clone_impl!(int)
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clone_impl!(i8)
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clone_impl!(i16)
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clone_impl!(i32)
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clone_impl!(i64)
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clone_impl!(uint)
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clone_impl!(u8)
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clone_impl!(u16)
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clone_impl!(u32)
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clone_impl!(u64)
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clone_impl!(f32)
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clone_impl!(f64)
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clone_impl!(())
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clone_impl!(bool)
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clone_impl!(char)
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macro_rules! extern_fn_clone(
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($($A:ident),*) => (
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#[experimental = "this may not be sufficient for fns with region parameters"]
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impl<$($A,)* ReturnType> Clone for extern "Rust" fn($($A),*) -> ReturnType {
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/// Return a copy of a function pointer
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#[inline]
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fn clone(&self) -> extern "Rust" fn($($A),*) -> ReturnType { *self }
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}
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)
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)
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extern_fn_clone!()
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extern_fn_clone!(A)
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extern_fn_clone!(A, B)
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extern_fn_clone!(A, B, C)
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extern_fn_clone!(A, B, C, D)
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extern_fn_clone!(A, B, C, D, E)
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extern_fn_clone!(A, B, C, D, E, F)
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extern_fn_clone!(A, B, C, D, E, F, G)
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extern_fn_clone!(A, B, C, D, E, F, G, H)
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