qubit_thread_pool/thread_pool/
thread_pool_build_error.rs

1/*******************************************************************************
2 *
3 *    Copyright (c) 2025 - 2026.
4 *    Haixing Hu, Qubit Co. Ltd.
5 *
6 *    All rights reserved.
7 *
8 ******************************************************************************/
9use std::io;
10
11use thiserror::Error;
12
13use qubit_executor::service::RejectedExecution;
14
15/// Error returned when a [`super::thread_pool::ThreadPool`] cannot be built.
16///
17/// # Author
18///
19/// Haixing Hu
20#[derive(Debug, Error)]
21pub enum ThreadPoolBuildError {
22    /// The configured maximum pool size is zero.
23    #[error("thread pool maximum pool size must be greater than zero")]
24    ZeroMaximumPoolSize,
25
26    /// The configured core pool size is greater than the maximum pool size.
27    #[error(
28        "thread pool core pool size {core_pool_size} exceeds maximum pool size {maximum_pool_size}"
29    )]
30    CorePoolSizeExceedsMaximum {
31        /// Configured core pool size.
32        core_pool_size: usize,
33
34        /// Configured maximum pool size.
35        maximum_pool_size: usize,
36    },
37
38    /// The configured bounded queue capacity is zero.
39    #[error("thread pool queue capacity must be greater than zero")]
40    ZeroQueueCapacity,
41
42    /// The configured worker stack size is zero.
43    #[error("thread pool stack size must be greater than zero")]
44    ZeroStackSize,
45
46    /// The configured keep-alive timeout is zero.
47    #[error("thread pool keep-alive timeout must be greater than zero")]
48    ZeroKeepAlive,
49
50    /// A worker thread could not be spawned.
51    #[error("failed to spawn thread pool worker {index}: {source}")]
52    SpawnWorker {
53        /// Index of the worker that failed to spawn.
54        index: usize,
55
56        /// I/O error reported by [`std::thread::Builder::spawn`].
57        source: io::Error,
58    },
59}
60
61impl ThreadPoolBuildError {
62    /// Converts a runtime worker-spawn rejection into a build error.
63    ///
64    /// # Parameters
65    ///
66    /// * `error` - Rejection produced while prestarting workers during build.
67    ///
68    /// # Returns
69    ///
70    /// A build error carrying equivalent failure context.
71    pub(crate) fn from_rejected_execution(error: RejectedExecution) -> Self {
72        match error {
73            RejectedExecution::WorkerSpawnFailed { source } => Self::SpawnWorker {
74                index: 0,
75                source: io::Error::new(source.kind(), source.to_string()),
76            },
77            RejectedExecution::Shutdown => Self::SpawnWorker {
78                index: 0,
79                source: io::Error::other("thread pool shut down during prestart"),
80            },
81            RejectedExecution::Saturated => Self::SpawnWorker {
82                index: 0,
83                source: io::Error::other("thread pool saturated during prestart"),
84            },
85        }
86    }
87}
88
89impl From<RejectedExecution> for ThreadPoolBuildError {
90    /// Converts rejected-execution reasons into build-time thread-pool errors.
91    ///
92    /// # Parameters
93    ///
94    /// * `error` - Rejection reason observed during thread prestart.
95    ///
96    /// # Returns
97    ///
98    /// A build error that preserves equivalent failure context.
99    fn from(error: RejectedExecution) -> Self {
100        Self::from_rejected_execution(error)
101    }
102}
qubit_thread_pool/thread_pool/thread_pool_build_error.rs

qubit_thread_pool/thread_pool/
thread_pool_build_error.rs
