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1 | 1 | pub use jobserver_crate::Client; |
2 | | -use std::sync::LazyLock; |
3 | | - |
4 | | -// We can only call `from_env` once per process |
5 | | - |
6 | | -// Note that this is unsafe because it may misinterpret file descriptors |
7 | | -// on Unix as jobserver file descriptors. We hopefully execute this near |
8 | | -// the beginning of the process though to ensure we don't get false |
9 | | -// positives, or in other words we try to execute this before we open |
10 | | -// any file descriptors ourselves. |
11 | | -// |
12 | | -// Pick a "reasonable maximum" if we don't otherwise have |
13 | | -// a jobserver in our environment, capping out at 32 so we |
14 | | -// don't take everything down by hogging the process run queue. |
15 | | -// The fixed number is used to have deterministic compilation |
16 | | -// across machines. |
17 | | -// |
18 | | -// Also note that we stick this in a global because there could be |
19 | | -// multiple rustc instances in this process, and the jobserver is |
20 | | -// per-process. |
21 | | -static GLOBAL_CLIENT: LazyLock<Client> = LazyLock::new(|| unsafe { |
22 | | - Client::from_env().unwrap_or_else(|| { |
23 | | - let client = Client::new(32).expect("failed to create jobserver"); |
24 | | - // Acquire a token for the main thread which we can release later |
25 | | - client.acquire_raw().ok(); |
26 | | - client |
27 | | - }) |
| 2 | + |
| 3 | +use jobserver_crate::{FromEnv, FromEnvErrorKind}; |
| 4 | + |
| 5 | +use std::sync::{LazyLock, OnceLock}; |
| 6 | + |
| 7 | +// We can only call `from_env_ext` once per process |
| 8 | + |
| 9 | +// We stick this in a global because there could be multiple rustc instances |
| 10 | +// in this process, and the jobserver is per-process. |
| 11 | +static GLOBAL_CLIENT: LazyLock<Result<Client, String>> = LazyLock::new(|| { |
| 12 | + // Note that this is unsafe because it may misinterpret file descriptors |
| 13 | + // on Unix as jobserver file descriptors. We hopefully execute this near |
| 14 | + // the beginning of the process though to ensure we don't get false |
| 15 | + // positives, or in other words we try to execute this before we open |
| 16 | + // any file descriptors ourselves. |
| 17 | + let FromEnv { client, var } = unsafe { Client::from_env_ext(true) }; |
| 18 | + |
| 19 | + let error = match client { |
| 20 | + Ok(client) => return Ok(client), |
| 21 | + Err(e) => e, |
| 22 | + }; |
| 23 | + |
| 24 | + if matches!( |
| 25 | + error.kind(), |
| 26 | + FromEnvErrorKind::NoEnvVar | FromEnvErrorKind::NoJobserver | FromEnvErrorKind::Unsupported |
| 27 | + ) { |
| 28 | + return Ok(default_client()); |
| 29 | + } |
| 30 | + |
| 31 | + // Environment specifies jobserver, but it looks incorrect. |
| 32 | + // Safety: `error.kind()` should be `NoEnvVar` if `var == None`. |
| 33 | + let (name, value) = var.unwrap(); |
| 34 | + Err(format!( |
| 35 | + "failed to connect to jobserver from environment variable `{name}={:?}`: {error}", |
| 36 | + value |
| 37 | + )) |
28 | 38 | }); |
29 | 39 |
|
| 40 | +// Create a new jobserver if there's no inherited one. |
| 41 | +fn default_client() -> Client { |
| 42 | + // Pick a "reasonable maximum" capping out at 32 |
| 43 | + // so we don't take everything down by hogging the process run queue. |
| 44 | + // The fixed number is used to have deterministic compilation across machines. |
| 45 | + let client = Client::new(32).expect("failed to create jobserver"); |
| 46 | + |
| 47 | + // Acquire a token for the main thread which we can release later |
| 48 | + client.acquire_raw().ok(); |
| 49 | + |
| 50 | + client |
| 51 | +} |
| 52 | + |
| 53 | +static GLOBAL_CLIENT_CHECKED: OnceLock<Client> = OnceLock::new(); |
| 54 | + |
| 55 | +pub fn check(report_warning: impl FnOnce(&'static str)) { |
| 56 | + let client_checked = match &*GLOBAL_CLIENT { |
| 57 | + Ok(client) => client.clone(), |
| 58 | + Err(e) => { |
| 59 | + report_warning(e); |
| 60 | + default_client() |
| 61 | + } |
| 62 | + }; |
| 63 | + GLOBAL_CLIENT_CHECKED.set(client_checked).ok(); |
| 64 | +} |
| 65 | + |
| 66 | +const ACCESS_ERROR: &str = "jobserver check should have been called earlier"; |
| 67 | + |
30 | 68 | pub fn client() -> Client { |
31 | | - GLOBAL_CLIENT.clone() |
| 69 | + GLOBAL_CLIENT_CHECKED.get().expect(ACCESS_ERROR).clone() |
32 | 70 | } |
33 | 71 |
|
34 | 72 | pub fn acquire_thread() { |
35 | | - GLOBAL_CLIENT.acquire_raw().ok(); |
| 73 | + GLOBAL_CLIENT_CHECKED.get().expect(ACCESS_ERROR).acquire_raw().ok(); |
36 | 74 | } |
37 | 75 |
|
38 | 76 | pub fn release_thread() { |
39 | | - GLOBAL_CLIENT.release_raw().ok(); |
| 77 | + GLOBAL_CLIENT_CHECKED.get().expect(ACCESS_ERROR).release_raw().ok(); |
40 | 78 | } |
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