0d5bcb14ad
Many of the modifications putting in `Box::new` calls also include a pointer to Issue 22405, which tracks going back to `box <expr>` if possible in the future. (Still tried to use `Box<_>` where it sufficed; thus some tests still have `box_syntax` enabled, as they use a mix of `box` and `Box::new`.) Precursor for overloaded-`box` and placement-`in`; see Issue 22181.
57 lines
1.4 KiB
Rust
57 lines
1.4 KiB
Rust
// Copyright 2014 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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// Because this module is temporary...
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#![allow(missing_docs)]
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#![unstable(feature = "std_misc")]
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use alloc::boxed::Box;
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use core::marker::Send;
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use core::ops::FnOnce;
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pub struct Thunk<'a, A=(),R=()> {
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invoke: Box<Invoke<A,R>+Send + 'a>,
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}
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impl<'a, R> Thunk<'a,(),R> {
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pub fn new<F>(func: F) -> Thunk<'a,(),R>
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where F : FnOnce() -> R, F : Send + 'a
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{
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Thunk::with_arg(move|()| func())
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}
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}
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impl<'a,A,R> Thunk<'a,A,R> {
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pub fn with_arg<F>(func: F) -> Thunk<'a,A,R>
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where F : FnOnce(A) -> R, F : Send + 'a
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{
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Thunk {
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invoke: Box::<F>::new(func)
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}
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}
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pub fn invoke(self, arg: A) -> R {
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self.invoke.invoke(arg)
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}
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}
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pub trait Invoke<A=(),R=()> {
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fn invoke(self: Box<Self>, arg: A) -> R;
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}
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impl<A,R,F> Invoke<A,R> for F
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where F : FnOnce(A) -> R
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{
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fn invoke(self: Box<F>, arg: A) -> R {
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let f = *self;
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f(arg)
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}
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}
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