Coverage Report

Created: 2025-08-28 07:05

/rust/registry/src/index.crates.io-6f17d22bba15001f/tracing-tree-0.2.5/src/time.rs
Line
Count
Source (jump to first uncovered line)
1
/// A type that can measure and format the current time.
2
///
3
/// This trait is used by [HierarchicalLayer] to include a timestamp with each
4
/// [Event] when it is logged.
5
///
6
/// Notable default implementations of this trait are [LocalDateTime] and `()`.
7
/// The former prints the current time as reported by [time's OffsetDateTime]
8
/// (note that it requires a `time` feature to be enabled and may panic!
9
/// make sure to check out the docs for the [LocalDateTime]),
10
/// and the latter does not print the current time at all.
11
///
12
/// Inspired by the [FormatTime] trait from [tracing-subscriber].
13
///
14
/// [HierarchicalLayer]: crate::HierarchicalLayer
15
/// [Event]: tracing_core::Event
16
/// [time's OffsetDateTime]: time::OffsetDateTime
17
/// [FormatTime]: tracing_subscriber::fmt::time::FormatTime
18
/// [tracing-subscriber]: tracing_subscriber
19
// NB:
20
//   We can't use `tracing_subscriber::fmt::format::Writer`
21
//   since it doesn't have a public constructor.
22
pub trait FormatTime {
23
    fn format_time(&self, w: &mut impl std::fmt::Write) -> std::fmt::Result;
24
}
25
26
////////////////////////////////////////////////////////////////////////////////////////////////////
27
28
/// Default do-nothing time formatter.
29
impl FormatTime for () {
30
0
    fn format_time(&self, _w: &mut impl std::fmt::Write) -> std::fmt::Result {
31
0
        Ok(())
32
0
    }
Unexecuted instantiation: <() as tracing_tree::time::FormatTime>::format_time::<&mut alloc::string::String>
Unexecuted instantiation: <() as tracing_tree::time::FormatTime>::format_time::<_>
33
}
34
35
////////////////////////////////////////////////////////////////////////////////////////////////////
36
37
/// Retrieve and print the current wall-clock time in UTC timezone.
38
#[cfg(feature = "time")]
39
#[derive(Debug, Clone, Copy, Eq, PartialEq, Default)]
40
pub struct UtcDateTime;
41
42
#[cfg(feature = "time")]
43
impl FormatTime for UtcDateTime {
44
    fn format_time(&self, w: &mut impl std::fmt::Write) -> std::fmt::Result {
45
        let time = time::OffsetDateTime::now_utc();
46
        write!(w, "{} {}", time.date(), time.time())
47
    }
48
}
49
50
////////////////////////////////////////////////////////////////////////////////////////////////////
51
52
/// Retrieve and print the current wall-clock time.
53
///
54
/// # Panics
55
///
56
/// Panics if [time crate] cannot determine the local UTC offset.
57
///
58
/// [time crate]: time
59
// NB:
60
//   Can't use `tracing_subscriber::fmt::time::SystemTime` since it uses
61
//   private `datetime` module to format the actual time.
62
#[cfg(feature = "time")]
63
#[derive(Debug, Clone, Copy, Eq, PartialEq, Default)]
64
pub struct LocalDateTime;
65
66
#[cfg(feature = "time")]
67
impl FormatTime for LocalDateTime {
68
    fn format_time(&self, w: &mut impl std::fmt::Write) -> std::fmt::Result {
69
        let time = time::OffsetDateTime::now_local().expect("time offset cannot be determined");
70
        write!(w, "{}", time)
71
    }
72
}
73
74
////////////////////////////////////////////////////////////////////////////////////////////////////
75
76
/// Retrieve and print the relative elapsed wall-clock time since an epoch.
77
///
78
/// The `Default` implementation for `Uptime` makes the epoch the current time.
79
// NB: Copy-pasted from `tracing-subscriber::fmt::time::Uptime`.
80
#[derive(Debug, Clone, Copy, Eq, PartialEq)]
81
pub struct Uptime {
82
    epoch: std::time::Instant,
83
}
84
85
impl Default for Uptime {
86
0
    fn default() -> Self {
87
0
        Uptime {
88
0
            epoch: std::time::Instant::now(),
89
0
        }
90
0
    }
91
}
92
93
impl From<std::time::Instant> for Uptime {
94
0
    fn from(epoch: std::time::Instant) -> Self {
95
0
        Uptime { epoch }
96
0
    }
97
}
98
99
impl FormatTime for Uptime {
100
0
    fn format_time(&self, w: &mut impl std::fmt::Write) -> std::fmt::Result {
101
0
        let e = self.epoch.elapsed();
102
0
        write!(w, "{:4}.{:06}s", e.as_secs(), e.subsec_micros())
103
0
    }
104
}
105
106
////////////////////////////////////////////////////////////////////////////////////////////////////
107
108
impl<'a, F> FormatTime for &'a F
109
where
110
    F: FormatTime,
111
{
112
0
    fn format_time(&self, w: &mut impl std::fmt::Write) -> std::fmt::Result {
113
0
        (*self).format_time(w)
114
0
    }
115
}
116
117
// NB:
118
//   Can't impl for `fn(&mut impl std::fmt::Write)` since impl trait is not allowed
119
//   outside of function and inherent method return types for now.