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Revert "tracing: ensmallerate assembly generated by macro expansions (#…
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…943)"
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@davidbarsky
davidbarsky committed Sep 24, 2020
1 parent 6f01226 commit 38a98b5
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Showing 5 changed files with 192 additions and 301 deletions.
102 changes: 26 additions & 76 deletions tracing-core/src/dispatcher.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -149,7 +149,7 @@ use crate::stdlib::{

#[cfg(feature = "std")]
use crate::stdlib::{
cell::{Cell, RefCell, RefMut},
cell::{Cell, RefCell},
error,
};

Expand Down Expand Up @@ -193,12 +193,6 @@ struct State {
can_enter: Cell<bool>,
}

/// While this guard is active, additional calls to subscriber functions on
/// the default dispatcher will not be able to access the dispatch context.
/// Dropping the guard will allow the dispatch context to be re-entered.
#[cfg(feature = "std")]
struct Entered<'a>(&'a State);

/// A guard that resets the current default dispatcher to the prior
/// default dispatcher when dropped.
#[cfg(feature = "std")]
Expand Down Expand Up @@ -331,46 +325,38 @@ pub fn get_default<T, F>(mut f: F) -> T
where
F: FnMut(&Dispatch) -> T,
{
// While this guard is active, additional calls to subscriber functions on
// the default dispatcher will not be able to access the dispatch context.
// Dropping the guard will allow the dispatch context to be re-entered.
struct Entered<'a>(&'a Cell<bool>);
impl<'a> Drop for Entered<'a> {
#[inline]
fn drop(&mut self) {
self.0.set(true);
}
}

CURRENT_STATE
.try_with(|state| {
if let Some(entered) = state.enter() {
return f(&*entered.current());
if state.can_enter.replace(false) {
let _guard = Entered(&state.can_enter);

let mut default = state.default.borrow_mut();

if default.is::<NoSubscriber>() {
if let Some(global) = get_global() {
// don't redo this call on the next check
*default = global.clone();
}
}
f(&*default)
} else {
f(&Dispatch::none())
}

f(&Dispatch::none())
})
.unwrap_or_else(|_| f(&Dispatch::none()))
}

/// Executes a closure with a reference to this thread's current [dispatcher].
///
/// Note that calls to `get_default` should not be nested; if this function is
/// called while inside of another `get_default`, that closure will be provided
/// with `Dispatch::none` rather than the previously set dispatcher.
///
/// [dispatcher]: ../dispatcher/struct.Dispatch.html
#[cfg(feature = "std")]
#[doc(hidden)]
#[inline(never)]
pub fn get_current<T>(f: impl FnOnce(&Dispatch) -> T) -> Option<T> {
CURRENT_STATE
.try_with(|state| {
let entered = state.enter()?;
Some(f(&*entered.current()))
})
.ok()?
}

/// Executes a closure with a reference to the current [dispatcher].
///
/// [dispatcher]: ../dispatcher/struct.Dispatch.html
#[cfg(not(feature = "std"))]
#[doc(hidden)]
pub fn get_current<T>(f: impl FnOnce(&Dispatch) -> T) -> Option<T> {
let dispatch = get_global()?;
Some(f(&dispatch))
}

/// Executes a closure with a reference to the current [dispatcher].
///
/// [dispatcher]: ../dispatcher/struct.Dispatch.html
Expand Down Expand Up @@ -725,42 +711,6 @@ impl State {
EXISTS.store(true, Ordering::Release);
DefaultGuard(prior)
}

#[inline]
fn enter(&self) -> Option<Entered<'_>> {
if self.can_enter.replace(false) {
Some(Entered(&self))
} else {
None
}
}
}

// ===== impl Entered =====

#[cfg(feature = "std")]
impl<'a> Entered<'a> {
#[inline]
fn current(&self) -> RefMut<'a, Dispatch> {
let mut default = self.0.default.borrow_mut();

if default.is::<NoSubscriber>() {
if let Some(global) = get_global() {
// don't redo this call on the next check
*default = global.clone();
}
}

default
}
}

#[cfg(feature = "std")]
impl<'a> Drop for Entered<'a> {
#[inline]
fn drop(&mut self) {
self.0.can_enter.set(true);
}
}

// ===== impl DefaultGuard =====
Expand Down
2 changes: 1 addition & 1 deletion tracing/Cargo.toml
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ keywords = ["logging", "tracing", "metrics", "async"]
edition = "2018"

[dependencies]
tracing-core = { path = "../tracing-core", version = "0.1.15", default-features = false }
tracing-core = { path = "../tracing-core", version = "0.1.14", default-features = false }
log = { version = "0.4", optional = true }
tracing-attributes = { path = "../tracing-attributes", version = "0.1.10", optional = true }
cfg-if = "0.1.10"
Expand Down
88 changes: 28 additions & 60 deletions tracing/src/lib.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -921,9 +921,9 @@ pub mod subscriber;

#[doc(hidden)]
pub mod __macro_support {
pub use crate::callsite::Callsite;
pub use crate::callsite::Callsite as _;
use crate::stdlib::sync::atomic::{AtomicUsize, Ordering};
use crate::{subscriber::Interest, Metadata};
use crate::{subscriber::Interest, Callsite, Metadata};
use tracing_core::Once;

/// Callsite implementation used by macro-generated code.
Expand Down Expand Up @@ -952,90 +952,58 @@ pub mod __macro_support {
/// without warning.
pub const fn new(meta: &'static Metadata<'static>) -> Self {
Self {
interest: AtomicUsize::new(0xDEADFACED),
interest: AtomicUsize::new(0),
meta,
registration: Once::new(),
}
}

/// Registers this callsite with the global callsite registry.
///
/// If the callsite is already registered, this does nothing.
/// Returns `true` if the callsite is enabled by a cached interest, or
/// by the current `Dispatch`'s `enabled` method if the cached
/// `Interest` is `sometimes`.
///
/// /!\ WARNING: This is *not* a stable API! /!\
/// This method, and all code contained in the `__macro_support` module, is
/// a *private* API of `tracing`. It is exposed publicly because it is used
/// by the `tracing` macros, but it is not part of the stable versioned API.
/// Breaking changes to this module may occur in small-numbered versions
/// without warning.
#[inline(never)]
// This only happens once (or if the cached interest value was corrupted).
#[cold]
pub fn register(&'static self) -> Interest {
self.registration
.call_once(|| crate::callsite::register(self));
match self.interest.load(Ordering::Relaxed) {
0 => Interest::never(),
2 => Interest::always(),
_ => Interest::sometimes(),
#[inline(always)]
pub fn is_enabled(&self) -> bool {
let interest = self.interest();
if interest.is_always() {
return true;
}
if interest.is_never() {
return false;
}

crate::dispatcher::get_default(|current| current.enabled(self.meta))
}

/// Returns the callsite's cached Interest, or registers it for the
/// first time if it has not yet been registered.
/// Registers this callsite with the global callsite registry.
///
/// If the callsite is already registered, this does nothing.
///
/// /!\ WARNING: This is *not* a stable API! /!\
/// This method, and all code contained in the `__macro_support` module, is
/// a *private* API of `tracing`. It is exposed publicly because it is used
/// by the `tracing` macros, but it is not part of the stable versioned API.
/// Breaking changes to this module may occur in small-numbered versions
/// without warning.
#[inline]
pub fn interest(&'static self) -> Interest {
#[inline(always)]
pub fn register(&'static self) {
self.registration
.call_once(|| crate::callsite::register(self));
}

#[inline(always)]
fn interest(&self) -> Interest {
match self.interest.load(Ordering::Relaxed) {
0 => Interest::never(),
1 => Interest::sometimes(),
2 => Interest::always(),
_ => self.register(),
}
}

pub fn dispatch_event(&'static self, interest: Interest, f: impl FnOnce(&crate::Dispatch)) {
tracing_core::dispatcher::get_current(|current| {
if interest.is_always() || current.enabled(self.meta) {
f(current)
}
});
}

#[inline]
#[cfg(feature = "log")]
pub fn disabled_span(&self) -> crate::Span {
crate::Span::new_disabled(self.meta)
}

#[inline]
#[cfg(not(feature = "log"))]
pub fn disabled_span(&self) -> crate::Span {
crate::Span::none()
}

pub fn dispatch_span(
&'static self,
interest: Interest,
f: impl FnOnce(&crate::Dispatch) -> crate::Span,
) -> crate::Span {
if interest.is_never() {
return self.disabled_span();
_ => Interest::sometimes(),
}

tracing_core::dispatcher::get_current(|current| {
if interest.is_always() || current.enabled(self.meta) {
return f(current);
}
self.disabled_span()
})
.unwrap_or_else(|| self.disabled_span())
}
}

Expand Down
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