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Make logging macros truly zero-cost abstraction #285

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Merged
0xNeshi merged 1 commit into from
Dec 25, 2025
Merged

Make logging macros truly zero-cost abstraction #285

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90 changes: 15 additions & 75 deletions src/logging.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,107 +3,47 @@
//! When the `tracing` feature is disabled, all logging calls compile to no-ops,
//! ensuring zero runtime cost for users who don't need observability.

#[cfg(feature = "tracing")]
#[allow(unused_macros)]
macro_rules! error {
($($arg:tt)*) => {
tracing::error!(target: "event_scanner", $($arg)*)
if cfg!(feature = "tracing") {
tracing::error!(target: "event_scanner", $($arg)*)
}
};
}

#[cfg(not(feature = "tracing"))]
#[allow(unused_macros)]
macro_rules! error {
($($arg:tt)*) => {
$crate::__trace_consume!($($arg)*)
};
}

#[cfg(feature = "tracing")]
#[allow(unused_macros)]
macro_rules! warn {
($($arg:tt)*) => {
tracing::warn!(target: "event_scanner", $($arg)*)
if cfg!(feature = "tracing") {
tracing::warn!(target: "event_scanner", $($arg)*)
}
};
}

#[cfg(not(feature = "tracing"))]
#[allow(unused_macros)]
macro_rules! warn {
($($arg:tt)*) => {
$crate::__trace_consume!($($arg)*)
};
}

#[cfg(feature = "tracing")]
#[allow(unused_macros)]
macro_rules! info {
($($arg:tt)*) => {
tracing::info!(target: "event_scanner", $($arg)*)
if cfg!(feature = "tracing") {
tracing::info!(target: "event_scanner", $($arg)*)
}
};
}

#[cfg(not(feature = "tracing"))]
#[allow(unused_macros)]
macro_rules! info {
($($arg:tt)*) => {
$crate::__trace_consume!($($arg)*)
};
}

#[cfg(feature = "tracing")]
#[allow(unused_macros)]
macro_rules! debug {
($($arg:tt)*) => {
tracing::debug!(target: "event_scanner", $($arg)*)
if cfg!(feature = "tracing") {
tracing::debug!(target: "event_scanner", $($arg)*)
}
};
}

#[cfg(not(feature = "tracing"))]
#[allow(unused_macros)]
macro_rules! debug {
($($arg:tt)*) => {
$crate::__trace_consume!($($arg)*)
};
}

#[cfg(feature = "tracing")]
#[allow(unused_macros)]
macro_rules! trace {
($($arg:tt)*) => {
tracing::trace!(target: "event_scanner", $($arg)*)
};
}

#[cfg(not(feature = "tracing"))]
#[allow(unused_macros)]
macro_rules! trace {
($($arg:tt)*) => {
$crate::__trace_consume!($($arg)*)
};
}

#[doc(hidden)]
#[macro_export]
#[cfg(not(feature = "tracing"))]
#[allow(unused_macros)]
macro_rules! __trace_consume {
// field = %expr, rest...
($field:ident = % $value:expr, $($rest:tt)*) => {
{ let _ = &$value; $crate::__trace_consume!($($rest)*); }
};
// field = ?expr, rest...
($field:ident = ? $value:expr, $($rest:tt)*) => {
{ let _ = &$value; $crate::__trace_consume!($($rest)*); }
};
// field = expr, rest...
($field:ident = $value:expr, $($rest:tt)*) => {
{ let _ = &$value; $crate::__trace_consume!($($rest)*); }
};
// String literal or other tokens - ignore
($lit:literal $($rest:tt)*) => {
$crate::__trace_consume!($($rest)*)
if cfg!(feature = "tracing") {
tracing::trace!(target: "event_scanner", $($arg)*)
}
};
// Base case - empty
() => {};
}