jdc_core/
dbg.rs

1//! Process-lifetime caches for debug environment flags.
2//!
3//! `std::env::var` takes a global lock and walks `environ` on every call; the
4//! structuring pipeline checks debug flags at many decision points, and that
5//! showed up as a measurable hotspot (`__findenv_locked` at ~2.4% of samples
6//! while rendering `rt.jar`). These flags are process-start configuration, so
7//! they are frozen on first use — semantics-preserving.
8
9/// Cached presence check for a debug env flag.
10#[macro_export]
11macro_rules! dbg_flag {
12    ($name:literal) => {{
13        static CACHED: std::sync::OnceLock<bool> = std::sync::OnceLock::new();
14        *CACHED.get_or_init(|| std::env::var($name).is_ok())
15    }};
16}
17
18/// Cached parsed value of a debug env flag.
19#[macro_export]
20macro_rules! dbg_value {
21    ($name:literal, $ty:ty) => {{
22        static CACHED: std::sync::OnceLock<Option<$ty>> = std::sync::OnceLock::new();
23        CACHED
24            .get_or_init(|| {
25                std::env::var($name)
26                    .ok()
27                    .and_then(|v| v.parse::<$ty>().ok())
28            })
29            .clone()
30    }};
31}
jdc_core/dbg.rs

jdc_core/
dbg.rs
