44 lines
984 B
Rust
44 lines
984 B
Rust
// Copyright 2012 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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#![feature(managed_boxes)]
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use std::cell::Cell;
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struct dtor {
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x: @Cell<int>,
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}
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#[unsafe_destructor]
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impl Drop for dtor {
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fn drop(&mut self) {
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// abuse access to shared mutable state to write this code
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self.x.set(self.x.get() - 1);
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}
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}
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fn unwrap<T>(o: Option<T>) -> T {
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match o {
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Some(v) => v,
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None => fail!()
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}
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}
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pub fn main() {
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let x = @Cell::new(1);
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{
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let b = Some(dtor { x:x });
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let _c = unwrap(b);
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}
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assert_eq!(x.get(), 0);
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}
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