sloop/
clock.rs

1use std::future::Future;
2use std::path::PathBuf;
3use std::pin::Pin;
4use std::time::{Duration, SystemTime, UNIX_EPOCH};
5
6use time::OffsetDateTime;
7use time::format_description::well_known::Rfc3339;
8
9pub trait Clock: Send + Sync {
10    fn now_ms(&self) -> i64;
11    fn local_minute(&self, timestamp_ms: i64) -> u16;
12    fn sleep_until(&self, deadline_ms: i64) -> Pin<Box<dyn Future<Output = ()> + Send + '_>>;
13}
14
15#[derive(Debug, Default)]
16pub struct SystemClock;
17
18impl Clock for SystemClock {
19    fn now_ms(&self) -> i64 {
20        SystemTime::now()
21            .duration_since(UNIX_EPOCH)
22            .map(|elapsed| elapsed.as_millis() as i64)
23            .unwrap_or(0)
24    }
25
26    fn local_minute(&self, timestamp_ms: i64) -> u16 {
27        local_minute(timestamp_ms)
28    }
29
30    fn sleep_until(&self, deadline_ms: i64) -> Pin<Box<dyn Future<Output = ()> + Send + '_>> {
31        Box::pin(async move {
32            loop {
33                let delay_ms = deadline_ms.saturating_sub(self.now_ms());
34                if delay_ms <= 0 {
35                    return;
36                }
37                // Recheck wall time so suspend and clock corrections cannot
38                // leave a long monotonic sleep armed past the local opening.
39                tokio::time::sleep(Duration::from_millis(delay_ms.min(30_000) as u64)).await;
40            }
41        })
42    }
43}
44
45/// File-backed clock used by integration tests that run the daemon as a child
46/// process. Advancing the integer timestamp in the file wakes pending timers.
47#[derive(Debug)]
48pub struct FileClock {
49    path: PathBuf,
50}
51
52impl FileClock {
53    pub fn new(path: PathBuf) -> Self {
54        Self { path }
55    }
56
57    fn read_now_ms(&self) -> i64 {
58        std::fs::read_to_string(&self.path)
59            .ok()
60            .and_then(|value| value.trim().parse().ok())
61            .unwrap_or(0)
62    }
63}
64
65impl Clock for FileClock {
66    fn now_ms(&self) -> i64 {
67        self.read_now_ms()
68    }
69
70    fn local_minute(&self, timestamp_ms: i64) -> u16 {
71        local_minute(timestamp_ms)
72    }
73
74    fn sleep_until(&self, deadline_ms: i64) -> Pin<Box<dyn Future<Output = ()> + Send + '_>> {
75        Box::pin(async move {
76            while self.now_ms() < deadline_ms {
77                tokio::time::sleep(Duration::from_millis(10)).await;
78            }
79        })
80    }
81}
82
83pub fn format_timestamp(timestamp_ms: i64) -> Option<String> {
84    OffsetDateTime::from_unix_timestamp_nanos(i128::from(timestamp_ms) * 1_000_000)
85        .ok()?
86        .format(&Rfc3339)
87        .ok()
88}
89
90/// Reads an RFC3339 timestamp back to milliseconds since the epoch — the
91/// inverse of `format_timestamp`, for renderings that hold only the
92/// envelope's string form and need to do arithmetic on it.
93pub fn parse_timestamp(text: &str) -> Option<i64> {
94    let at = OffsetDateTime::parse(text, &Rfc3339).ok()?;
95    i64::try_from(at.unix_timestamp_nanos() / 1_000_000).ok()
96}
97
98/// Finds the next real instant whose local wall clock matches `minute`.
99/// Starting at the next whole minute makes the current minute mean its next
100/// occurrence, while scanning real instants handles DST transitions.
101pub fn next_local_minute_ms(clock: &dyn Clock, now_ms: i64, minute: u16) -> Option<i64> {
102    let mut candidate = now_ms
103        .div_euclid(60_000)
104        .checked_add(1)?
105        .checked_mul(60_000)?;
106    for _ in 0..=(49 * 60) {
107        if clock.local_minute(candidate) == minute {
108            return Some(candidate);
109        }
110        candidate = candidate.checked_add(60_000)?;
111    }
112    None
113}
114
115/// A timestamp's local wall-clock fields. History views render times the way
116/// an operator reads a clock, so they need the local date as well as the
117/// local time: a span that crosses midnight has to widen from `HH:MM` to a
118/// dated form, and only the calendar day can tell them that.
119#[derive(Debug, Clone, Copy, PartialEq, Eq)]
120pub struct LocalTime {
121    pub year: i32,
122    pub month: u8,
123    pub day: u8,
124    pub hour: u8,
125    pub minute: u8,
126}
127
128impl LocalTime {
129    /// `HH:MM` — the default form, used whenever the surrounding context
130    /// already fixes the day.
131    pub fn clock(&self) -> String {
132        format!("{:02}:{:02}", self.hour, self.minute)
133    }
134
135    /// `MM-DD HH:MM` — the widened form for a timestamp whose day the reader
136    /// cannot infer. Year is omitted; `sloop` history is read in the small.
137    pub fn dated(&self) -> String {
138        format!(
139            "{:02}-{:02} {:02}:{:02}",
140            self.month, self.day, self.hour, self.minute
141        )
142    }
143
144    /// Whether two instants fall on the same local calendar day, which is what
145    /// decides between `clock` and `dated`.
146    pub fn same_day(&self, other: &Self) -> bool {
147        (self.year, self.month, self.day) == (other.year, other.month, other.day)
148    }
149}
150
151/// Breaks a millisecond timestamp into local wall-clock fields. Uses the same
152/// `localtime_r` path as `local_minute` so scheduling and rendering agree on
153/// what "local" means, including across DST.
154pub fn local_time(timestamp_ms: i64) -> Option<LocalTime> {
155    let seconds = timestamp_ms.div_euclid(1_000) as libc::time_t;
156    let mut local = unsafe { std::mem::zeroed::<libc::tm>() };
157    let result = unsafe { libc::localtime_r(&seconds, &mut local) };
158    if result.is_null() {
159        return None;
160    }
161    Some(LocalTime {
162        year: local.tm_year + 1900,
163        month: (local.tm_mon + 1) as u8,
164        day: local.tm_mday as u8,
165        hour: local.tm_hour as u8,
166        minute: local.tm_min as u8,
167    })
168}
169
170fn local_minute(timestamp_ms: i64) -> u16 {
171    let seconds = timestamp_ms.div_euclid(1_000) as libc::time_t;
172    let mut local = unsafe { std::mem::zeroed::<libc::tm>() };
173    let result = unsafe { libc::localtime_r(&seconds, &mut local) };
174    if result.is_null() {
175        return 0;
176    }
177    (local.tm_hour as u16) * 60 + local.tm_min as u16
178}
179
180#[cfg(test)]
181mod tests {
182    use super::parse_timestamp;
183
184    #[test]
185    fn a_whole_second_instant_parses_to_its_epoch_millisecond() {
186        assert_eq!(
187            parse_timestamp("2026-07-15T22:00:00Z"),
188            Some(1_784_152_800_000)
189        );
190    }
191
192    /// The daemon stamps envelopes with millisecond precision, so the
193    /// fraction is the common case rather than the exotic one.
194    #[test]
195    fn a_fractional_second_instant_keeps_its_milliseconds() {
196        assert_eq!(
197            parse_timestamp("2026-07-26T11:03:39.687Z"),
198            Some(1_785_063_819_687)
199        );
200    }
201
202    #[test]
203    fn a_numeric_offset_resolves_to_the_same_instant_as_its_z_form() {
204        assert_eq!(
205            parse_timestamp("2026-07-15T22:00:00+10:00"),
206            parse_timestamp("2026-07-15T12:00:00Z")
207        );
208    }
209
210    #[test]
211    fn anything_that_is_not_rfc3339_is_none() {
212        assert_eq!(parse_timestamp("not-a-time"), None);
213        assert_eq!(parse_timestamp(""), None);
214        assert_eq!(parse_timestamp("2026-07-15"), None);
215    }
216}
sloop/clock.rs

sloop/
clock.rs
