qubit_executor/task/
task_execution_error.rs

1/*******************************************************************************
2 *
3 *    Copyright (c) 2025 - 2026.
4 *    Haixing Hu, Qubit Co. Ltd.
5 *
6 *    All rights reserved.
7 *
8 ******************************************************************************/
9use std::{
10    error::Error,
11    fmt,
12};
13
14/// Result type used by managed task handles.
15pub type TaskResult<R, E> = Result<R, TaskExecutionError<E>>;
16
17/// Error observed when retrieving the result of an accepted task.
18///
19/// This error is distinct from [`RejectedExecution`](crate::service::RejectedExecution).
20/// Rejection happens before a service accepts a task; `TaskExecutionError`
21/// describes what happened after the task was accepted.
22///
23/// # Type Parameters
24///
25/// * `E` - The error type returned by the task itself.
26///
27/// # Author
28///
29/// Haixing Hu
30#[derive(Debug)]
31pub enum TaskExecutionError<E> {
32    /// The task ran and returned `Err(E)`.
33    Failed(E),
34
35    /// The task panicked while running.
36    Panicked,
37
38    /// The task was cancelled before producing a result.
39    Cancelled,
40}
41
42impl<E> TaskExecutionError<E> {
43    /// Returns true when this error wraps the task's own error value.
44    ///
45    /// # Returns
46    ///
47    /// `true` if the task returned `Err(E)`.
48    #[inline]
49    pub const fn is_failed(&self) -> bool {
50        matches!(self, Self::Failed(_))
51    }
52
53    /// Returns true when the task panicked.
54    ///
55    /// # Returns
56    ///
57    /// `true` if the task panicked while running.
58    #[inline]
59    pub const fn is_panicked(&self) -> bool {
60        matches!(self, Self::Panicked)
61    }
62
63    /// Returns true when the task was cancelled.
64    ///
65    /// # Returns
66    ///
67    /// `true` if the task was cancelled before producing a result.
68    #[inline]
69    pub const fn is_cancelled(&self) -> bool {
70        matches!(self, Self::Cancelled)
71    }
72}
73
74impl<E> fmt::Display for TaskExecutionError<E>
75where
76    E: fmt::Display,
77{
78    /// Formats this task execution error for users.
79    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
80        match self {
81            Self::Failed(err) => write!(f, "task failed: {err}"),
82            Self::Panicked => f.write_str("task panicked"),
83            Self::Cancelled => f.write_str("task was cancelled"),
84        }
85    }
86}
87
88impl<E> Error for TaskExecutionError<E> where E: Error + 'static {}
qubit_executor/task/task_execution_error.rs

qubit_executor/task/
task_execution_error.rs
