qubit_thread_pool/thread_pool/
thread_pool_build_error.rs

1/*******************************************************************************
2 *
3 *    Copyright (c) 2025 - 2026 Haixing Hu.
4 *
5 *    SPDX-License-Identifier: Apache-2.0
6 *
7 *    Licensed under the Apache License, Version 2.0.
8 *
9 ******************************************************************************/
10use std::io;
11
12use thiserror::Error;
13
14use qubit_executor::service::RejectedExecution;
15
16/// Error returned when a [`super::thread_pool::ThreadPool`] cannot be built.
17///
18#[derive(Debug, Error)]
19pub enum ThreadPoolBuildError {
20    /// The configured maximum pool size is zero.
21    #[error("thread pool maximum pool size must be greater than zero")]
22    ZeroMaximumPoolSize,
23
24    /// The configured core pool size is greater than the maximum pool size.
25    #[error(
26        "thread pool core pool size {core_pool_size} exceeds maximum pool size {maximum_pool_size}"
27    )]
28    CorePoolSizeExceedsMaximum {
29        /// Configured core pool size.
30        core_pool_size: usize,
31
32        /// Configured maximum pool size.
33        maximum_pool_size: usize,
34    },
35
36    /// The configured bounded queue capacity is zero.
37    #[error("thread pool queue capacity must be greater than zero")]
38    ZeroQueueCapacity,
39
40    /// The configured worker stack size is zero.
41    #[error("thread pool stack size must be greater than zero")]
42    ZeroStackSize,
43
44    /// The configured keep-alive timeout is zero.
45    #[error("thread pool keep-alive timeout must be greater than zero")]
46    ZeroKeepAlive,
47
48    /// A worker thread could not be spawned.
49    #[error("failed to spawn thread pool worker {index}: {source}")]
50    SpawnWorker {
51        /// Index of the worker that failed to spawn.
52        index: usize,
53
54        /// I/O error reported by [`std::thread::Builder::spawn`].
55        source: io::Error,
56    },
57}
58
59impl ThreadPoolBuildError {
60    /// Converts a runtime worker-spawn rejection into a build error.
61    ///
62    /// # Parameters
63    ///
64    /// * `error` - Rejection produced while prestarting workers during build.
65    ///
66    /// # Returns
67    ///
68    /// A build error carrying equivalent failure context.
69    pub(crate) fn from_rejected_execution(error: RejectedExecution) -> Self {
70        match error {
71            RejectedExecution::WorkerSpawnFailed { source } => Self::SpawnWorker {
72                index: 0,
73                source: io::Error::new(source.kind(), source.to_string()),
74            },
75            RejectedExecution::Shutdown => Self::SpawnWorker {
76                index: 0,
77                source: io::Error::other("thread pool shut down during prestart"),
78            },
79            RejectedExecution::Saturated => Self::SpawnWorker {
80                index: 0,
81                source: io::Error::other("thread pool saturated during prestart"),
82            },
83        }
84    }
85}
86
87impl From<RejectedExecution> for ThreadPoolBuildError {
88    /// Converts rejected-execution reasons into build-time thread-pool errors.
89    ///
90    /// # Parameters
91    ///
92    /// * `error` - Rejection reason observed during thread prestart.
93    ///
94    /// # Returns
95    ///
96    /// A build error that preserves equivalent failure context.
97    fn from(error: RejectedExecution) -> Self {
98        Self::from_rejected_execution(error)
99    }
100}
qubit_thread_pool/thread_pool/thread_pool_build_error.rs

qubit_thread_pool/thread_pool/
thread_pool_build_error.rs
