🛈 Note: This is pre-release documentation for the upcoming tracing 0.2.0 ecosystem.

For the release documentation, please see docs.rs, instead. 

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69

//! [Subscribers](crate::subscribe) that control which spans and events are
//! enabled by the wrapped collector.
//!
//! This module contains a number of types that provide implementations of
//! various strategies for filtering which spans and events are enabled. For
//! details on filtering spans and events using [`Subscribe`] implementations,
//! see the [`subscribe` module documentation].
//!
//! [`subscribe` module documentation]: crate::subscribe#filtering-with-subscribers
//! [`Subscribe`]: crate::subscribe
mod filter_fn;
mod level;

feature! {
    #![all(feature = "env-filter", feature = "std")]
    mod env;
    pub use self::env::*;
}

feature! {
    #![all(feature = "registry", feature = "std")]
    mod subscriber_filters;
    pub use self::subscriber_filters::*;
}

pub use self::filter_fn::*;
#[cfg(not(feature = "registry"))]
pub(crate) use self::has_psf_stubs::*;

pub use self::level::{LevelFilter, ParseError as LevelParseError};

#[cfg(not(all(feature = "registry", feature = "std")))]
#[allow(unused_imports)]
pub(crate) use self::has_psf_stubs::*;

feature! {
    #![any(feature = "std", feature = "alloc")]
    pub mod targets;
    pub use self::targets::Targets;

    mod directive;
    pub use self::directive::ParseError;
}

/// Stub implementations of the per-subscriber-filter detection functions for
/// when the `registry` feature is disabled.
#[cfg(not(all(feature = "registry", feature = "std")))]
mod has_psf_stubs {
    pub(crate) fn is_psf_downcast_marker(_: core::any::TypeId) -> bool {
        false
    }

    /// Does a type implementing `Collect` contain any per-subscriber filters?
    pub(crate) fn collector_has_psf<C>(_: &C) -> bool
    where
        C: tracing_core::Collect,
    {
        false
    }

    /// Does a type implementing `Subscribe` contain any per-subscriber filters?
    pub(crate) fn subscriber_has_psf<S, C>(_: &S) -> bool
    where
        S: crate::Subscribe<C>,
        C: tracing_core::Collect,
    {
        false
    }
}