vendor/anyhow/tests/drop/mod.rs

   1 #![allow(clippy::module_name_repetitions)]
   2
   3 use std::error::Error as StdError;
   4 use std::fmt::{self, Display};
   5 use std::sync::atomic::AtomicBool;
   6 use std::sync::atomic::Ordering::SeqCst;
   7 use std::sync::Arc;
   8
   9 #[derive(Debug)]
  10 pub struct Flag {
  11     atomic: Arc<AtomicBool>,
  12 }
  13
  14 impl Flag {
  15     pub fn new() -> Self {
  16         Flag {
  17             atomic: Arc::new(AtomicBool::new(false)),
  18         }
  19     }
  20
  21     pub fn get(&self) -> bool {
  22         self.atomic.load(SeqCst)
  23     }
  24 }
  25
  26 #[derive(Debug)]
  27 pub struct DetectDrop {
  28     has_dropped: Flag,
  29 }
  30
  31 impl DetectDrop {
  32     pub fn new(has_dropped: &Flag) -> Self {
  33         DetectDrop {
  34             has_dropped: Flag {
  35                 atomic: Arc::clone(&has_dropped.atomic),
  36             },
  37         }
  38     }
  39 }
  40
  41 impl StdError for DetectDrop {}
  42
  43 impl Display for DetectDrop {
  44     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  45         write!(f, "oh no!")
  46     }
  47 }
  48
  49 impl Drop for DetectDrop {
  50     fn drop(&mut self) {
  51         let already_dropped = self.has_dropped.atomic.swap(true, SeqCst);
  52         assert!(!already_dropped);
  53     }
  54 }