Trait panic_control::ThreadResultExt [−] [src]

pub trait ThreadResultExt<T>: ThreadResultExtSealed {
    fn unwrap_or_propagate(self) -> T;

    fn panic_value_as_str(&self) -> Option<&str>;
}

Helpful extension methods for std::thread::Result.

The Result type defined in std::thread is a specialization of the standard Result with a Box<Any> in the Err variant, which receives the payload value of a panic. As such, Result does not provide convenient ways to examine the content of the panic value. Furthermore, the generic implementations of unwrap() and related methods use the Debug implementation of the content of Err to format the panic message, which is not very useful in case of Any.

When this trait is used in a lexical scope, it augments any Result value that matches the specialization of std::thread::Result with methods that facilitate examination and reporting of the possible string value which is most often found in the dynamically typed Err variant. The methods are meant to be used on the result of std::thread::JoinHandle::join() or CheckedJoinHandle::join().

Examples

use panic_control::ThreadResultExt;

use panic_control::Context;
use std::thread;

let h = thread::spawn(|| {
    42
});
let n = h.join().unwrap_or_propagate();
assert_eq!(n, 42);

#[derive(Debug, PartialEq, Eq)]
struct Expected;

let ctx = Context::<Expected>::new();
let h = ctx.spawn_quiet(|| {
    panic!("No coffee beans left in the bag!");
});
let res = h.join();
let msg = res.panic_value_as_str().unwrap();
println!("{}", msg);

Required Methods

Unwraps a result, yielding the content of an Ok.

Panics

Panics if the value is an Err, with a panic message appended with the Err's string value if that is found to be such, or a generic message otherwise. The message is meant to relay information from a panic in a child thread that is observed through this result value, as returned by std::thread::JoinHandle::join() or CheckedJoinHandle::join().

If the value is an Err and its content is a string, returns the content as a string slice. Otherwise returns None.

Implementations on Foreign Types

impl<T> ThreadResultExt<T> for Result<T>
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Implementors