src/test/run-pass/generator/conditional-drop.rs

   1 // Copyright 2017 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 #![feature(generators, generator_trait)]
  12
  13 use std::ops::Generator;
  14 use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
  15
  16 static A: AtomicUsize = ATOMIC_USIZE_INIT;
  17
  18 struct B;
  19
  20 impl Drop for B {
  21     fn drop(&mut self) {
  22         A.fetch_add(1, Ordering::SeqCst);
  23     }
  24 }
  25
  26
  27 fn test() -> bool { true }
  28 fn test2() -> bool { false }
  29
  30 fn main() {
  31     t1();
  32     t2();
  33 }
  34
  35 fn t1() {
  36     let mut a = || {
  37         let b = B;
  38         if test() {
  39             drop(b);
  40         }
  41         yield;
  42     };
  43
  44     let n = A.load(Ordering::SeqCst);
  45     unsafe { a.resume() };
  46     assert_eq!(A.load(Ordering::SeqCst), n + 1);
  47     unsafe { a.resume() };
  48     assert_eq!(A.load(Ordering::SeqCst), n + 1);
  49 }
  50
  51 fn t2() {
  52     let mut a = || {
  53         let b = B;
  54         if test2() {
  55             drop(b);
  56         }
  57         yield;
  58     };
  59
  60     let n = A.load(Ordering::SeqCst);
  61     unsafe { a.resume() };
  62     assert_eq!(A.load(Ordering::SeqCst), n);
  63     unsafe { a.resume() };
  64     assert_eq!(A.load(Ordering::SeqCst), n + 1);
  65 }