/rust/registry/src/index.crates.io-6f17d22bba15001f/time-0.3.37/src/instant.rs

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//! The [`Instant`] struct and its associated `impl`s.

#![allow(deprecated)]

use core::borrow::Borrow;
use core::cmp::{Ord, Ordering, PartialEq, PartialOrd};
use core::ops::{Add, Sub};
use core::time::Duration as StdDuration;
use std::time::Instant as StdInstant;

use crate::internal_macros::{impl_add_assign, impl_sub_assign};
use crate::Duration;

/// A measurement of a monotonically non-decreasing clock. Opaque and useful only with [`Duration`].
///
/// Instants are always guaranteed to be no less than any previously measured instant when created,
/// and are often useful for tasks such as measuring benchmarks or timing how long an operation
/// takes.
///
/// Note, however, that instants are not guaranteed to be **steady**. In other words, each tick of
/// the underlying clock may not be the same length (e.g. some seconds may be longer than others).
/// An instant may jump forwards or experience time dilation (slow down or speed up), but it will
/// never go backwards.
///
/// Instants are opaque types that can only be compared to one another. There is no method to get
/// "the number of seconds" from an instant. Instead, it only allows measuring the duration between
/// two instants (or comparing two instants).
///
/// This implementation allows for operations with signed [`Duration`]s, but is otherwise identical
/// to [`std::time::Instant`].
#[doc(hidden)]
#[deprecated(
    since = "0.3.35",
    note = "import `std::time::Instant` and `time::ext::InstantExt` instead"
)]
#[repr(transparent)]
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Instant(pub StdInstant);

impl Instant {
    // region: delegation
    /// Returns an `Instant` corresponding to "now".
    ///
    /// ```rust
    /// # #![allow(deprecated)]
    /// # use time::Instant;
    /// println!("{:?}", Instant::now());
    /// ```
    pub fn now() -> Self {
        Self(StdInstant::now())
    }

    /// Returns the amount of time elapsed since this instant was created. The duration will always
    /// be nonnegative if the instant is not synthetically created.
    ///
    /// ```rust
    /// # #![allow(deprecated)]
    /// # use time::{Instant, ext::{NumericalStdDuration, NumericalDuration}};
    /// # use std::thread;
    /// let instant = Instant::now();
    /// thread::sleep(1.std_milliseconds());
    /// assert!(instant.elapsed() >= 1.milliseconds());
    /// ```
    pub fn elapsed(self) -> Duration {
        Self::now() - self
    }
    // endregion delegation

    // region: checked arithmetic
    /// Returns `Some(t)` where `t` is the time `self + duration` if `t` can be represented as
    /// `Instant` (which means it's inside the bounds of the underlying data structure), `None`
    /// otherwise.
    ///
    /// ```rust
    /// # #![allow(deprecated)]
    /// # use time::{Instant, ext::NumericalDuration};
    /// let now = Instant::now();
    /// assert_eq!(now.checked_add(5.seconds()), Some(now + 5.seconds()));
    /// assert_eq!(now.checked_add((-5).seconds()), Some(now + (-5).seconds()));
    /// ```
    pub fn checked_add(self, duration: Duration) -> Option<Self> {
        if duration.is_zero() {
            Some(self)
        } else if duration.is_positive() {
            self.0.checked_add(duration.unsigned_abs()).map(Self)
        } else {
            debug_assert!(duration.is_negative());
            self.0.checked_sub(duration.unsigned_abs()).map(Self)
        }
    }

    /// Returns `Some(t)` where `t` is the time `self - duration` if `t` can be represented as
    /// `Instant` (which means it's inside the bounds of the underlying data structure), `None`
    /// otherwise.
    ///
    /// ```rust
    /// # #![allow(deprecated)]
    /// # use time::{Instant, ext::NumericalDuration};
    /// let now = Instant::now();
    /// assert_eq!(now.checked_sub(5.seconds()), Some(now - 5.seconds()));
    /// assert_eq!(now.checked_sub((-5).seconds()), Some(now - (-5).seconds()));
    /// ```
    pub fn checked_sub(self, duration: Duration) -> Option<Self> {
        if duration.is_zero() {
            Some(self)
        } else if duration.is_positive() {
            self.0.checked_sub(duration.unsigned_abs()).map(Self)
        } else {
            debug_assert!(duration.is_negative());
            self.0.checked_add(duration.unsigned_abs()).map(Self)
        }
    }
    // endregion checked arithmetic

    /// Obtain the inner [`std::time::Instant`].
    ///
    /// ```rust
    /// # #![allow(deprecated)]
    /// # use time::Instant;
    /// let now = Instant::now();
    /// assert_eq!(now.into_inner(), now.0);
    /// ```
    pub const fn into_inner(self) -> StdInstant {
        self.0
    }
}

// region: trait impls
impl From<StdInstant> for Instant {
    fn from(instant: StdInstant) -> Self {
        Self(instant)
    }
}

impl From<Instant> for StdInstant {
    fn from(instant: Instant) -> Self {
        instant.0
    }
}

impl Sub for Instant {
    type Output = Duration;

    /// # Panics
    ///
    /// This may panic if an overflow occurs.
    fn sub(self, other: Self) -> Self::Output {
        match self.0.cmp(&other.0) {
            Ordering::Equal => Duration::ZERO,
            Ordering::Greater => (self.0 - other.0)
                .try_into()
                .expect("overflow converting `std::time::Duration` to `time::Duration`"),
            Ordering::Less => -Duration::try_from(other.0 - self.0)
                .expect("overflow converting `std::time::Duration` to `time::Duration`"),
        }
    }
}

impl Sub<StdInstant> for Instant {
    type Output = Duration;

    fn sub(self, other: StdInstant) -> Self::Output {
        self - Self(other)
    }
}

impl Sub<Instant> for StdInstant {
    type Output = Duration;

    fn sub(self, other: Instant) -> Self::Output {
        Instant(self) - other
    }
}

impl Add<Duration> for Instant {
    type Output = Self;

    /// # Panics
    ///
    /// This function may panic if the resulting point in time cannot be represented by the
    /// underlying data structure.
    fn add(self, duration: Duration) -> Self::Output {
        if duration.is_positive() {
            Self(self.0 + duration.unsigned_abs())
        } else if duration.is_negative() {
            #[allow(clippy::unchecked_duration_subtraction)]
            Self(self.0 - duration.unsigned_abs())
        } else {
            debug_assert!(duration.is_zero());
            self
        }
    }
}

impl Add<Duration> for StdInstant {
    type Output = Self;

    fn add(self, duration: Duration) -> Self::Output {
        (Instant(self) + duration).0
    }
}

impl Add<StdDuration> for Instant {
    type Output = Self;

    fn add(self, duration: StdDuration) -> Self::Output {
        Self(self.0 + duration)
    }
}

impl_add_assign!(Instant: Duration, StdDuration);
impl_add_assign!(StdInstant: Duration);

impl Sub<Duration> for Instant {
    type Output = Self;

    /// # Panics
    ///
    /// This function may panic if the resulting point in time cannot be represented by the
    /// underlying data structure.
    fn sub(self, duration: Duration) -> Self::Output {
        if duration.is_positive() {
            #[allow(clippy::unchecked_duration_subtraction)]
            Self(self.0 - duration.unsigned_abs())
        } else if duration.is_negative() {
            Self(self.0 + duration.unsigned_abs())
        } else {
            debug_assert!(duration.is_zero());
            self
        }
    }
}

impl Sub<Duration> for StdInstant {
    type Output = Self;

    fn sub(self, duration: Duration) -> Self::Output {
        (Instant(self) - duration).0
    }
}

impl Sub<StdDuration> for Instant {
    type Output = Self;

    /// # Panics
    ///
    /// This function may panic if the resulting point in time cannot be represented by the
    /// underlying data structure.
    fn sub(self, duration: StdDuration) -> Self::Output {
        #[allow(clippy::unchecked_duration_subtraction)]
        Self(self.0 - duration)
    }
}

impl_sub_assign!(Instant: Duration, StdDuration);
impl_sub_assign!(StdInstant: Duration);

impl PartialEq<StdInstant> for Instant {
    fn eq(&self, rhs: &StdInstant) -> bool {
        self.0.eq(rhs)
    }
}

impl PartialEq<Instant> for StdInstant {
    fn eq(&self, rhs: &Instant) -> bool {
        self.eq(&rhs.0)
    }
}

impl PartialOrd<StdInstant> for Instant {
    fn partial_cmp(&self, rhs: &StdInstant) -> Option<Ordering> {
        self.0.partial_cmp(rhs)
    }
}

impl PartialOrd<Instant> for StdInstant {
    fn partial_cmp(&self, rhs: &Instant) -> Option<Ordering> {
        self.partial_cmp(&rhs.0)
    }
}

impl AsRef<StdInstant> for Instant {
    fn as_ref(&self) -> &StdInstant {
        &self.0
    }
}

impl Borrow<StdInstant> for Instant {
    fn borrow(&self) -> &StdInstant {
        &self.0
    }
}
// endregion trait impls

Coverage Report

Created: 2025-07-18 06:22

Line	Count	Source (jump to first uncovered line)
1		//! The [`Instant`] struct and its associated `impl`s.
2
3		#![allow(deprecated)]
4
5		use core::borrow::Borrow;
6		use core::cmp::{Ord, Ordering, PartialEq, PartialOrd};
7		use core::ops::{Add, Sub};
8		use core::time::Duration as StdDuration;
9		use std::time::Instant as StdInstant;
10
11		use crate::internal_macros::{impl_add_assign, impl_sub_assign};
12		use crate::Duration;
13
14		/// A measurement of a monotonically non-decreasing clock. Opaque and useful only with [`Duration`].
15		///
16		/// Instants are always guaranteed to be no less than any previously measured instant when created,
17		/// and are often useful for tasks such as measuring benchmarks or timing how long an operation
18		/// takes.
19		///
20		/// Note, however, that instants are not guaranteed to be steady. In other words, each tick of
21		/// the underlying clock may not be the same length (e.g. some seconds may be longer than others).
22		/// An instant may jump forwards or experience time dilation (slow down or speed up), but it will
23		/// never go backwards.
24		///
25		/// Instants are opaque types that can only be compared to one another. There is no method to get
26		/// "the number of seconds" from an instant. Instead, it only allows measuring the duration between
27		/// two instants (or comparing two instants).
28		///
29		/// This implementation allows for operations with signed [`Duration`]s, but is otherwise identical
30		/// to [`std::time::Instant`].
31		#[doc(hidden)]
32		#[deprecated(
33		since = "0.3.35",
34		note = "import `std::time::Instant` and `time::ext::InstantExt` instead"
35		)]
36		#[repr(transparent)]
37		#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
38		pub struct Instant(pub StdInstant);
39
40		impl Instant {
41		// region: delegation
42		/// Returns an `Instant` corresponding to "now".
43		///
44		/// ```rust
45		/// # #![allow(deprecated)]
46		/// # use time::Instant;
47		/// println!("{:?}", Instant::now());
48		/// ```
49	0	pub fn now() -> Self {
50	0	Self(StdInstant::now())
51	0	}
52
53		/// Returns the amount of time elapsed since this instant was created. The duration will always
54		/// be nonnegative if the instant is not synthetically created.
55		///
56		/// ```rust
57		/// # #![allow(deprecated)]
58		/// # use time::{Instant, ext::{NumericalStdDuration, NumericalDuration}};
59		/// # use std::thread;
60		/// let instant = Instant::now();
61		/// thread::sleep(1.std_milliseconds());
62		/// assert!(instant.elapsed() >= 1.milliseconds());
63		/// ```
64	0	pub fn elapsed(self) -> Duration {
65	0	Self::now() - self
66	0	}
67		// endregion delegation
68
69		// region: checked arithmetic
70		/// Returns `Some(t)` where `t` is the time `self + duration` if `t` can be represented as
71		/// `Instant` (which means it's inside the bounds of the underlying data structure), `None`
72		/// otherwise.
73		///
74		/// ```rust
75		/// # #![allow(deprecated)]
76		/// # use time::{Instant, ext::NumericalDuration};
77		/// let now = Instant::now();
78		/// assert_eq!(now.checked_add(5.seconds()), Some(now + 5.seconds()));
79		/// assert_eq!(now.checked_add((-5).seconds()), Some(now + (-5).seconds()));
80		/// ```
81	0	pub fn checked_add(self, duration: Duration) -> Option<Self> {
82	0	if duration.is_zero() {
83	0	Some(self)
84	0	} else if duration.is_positive() {
85	0	self.0.checked_add(duration.unsigned_abs()).map(Self)
86		} else {
87	0	debug_assert!(duration.is_negative());
88	0	self.0.checked_sub(duration.unsigned_abs()).map(Self)
89		}
90	0	}
91
92		/// Returns `Some(t)` where `t` is the time `self - duration` if `t` can be represented as
93		/// `Instant` (which means it's inside the bounds of the underlying data structure), `None`
94		/// otherwise.
95		///
96		/// ```rust
97		/// # #![allow(deprecated)]
98		/// # use time::{Instant, ext::NumericalDuration};
99		/// let now = Instant::now();
100		/// assert_eq!(now.checked_sub(5.seconds()), Some(now - 5.seconds()));
101		/// assert_eq!(now.checked_sub((-5).seconds()), Some(now - (-5).seconds()));
102		/// ```
103	0	pub fn checked_sub(self, duration: Duration) -> Option<Self> {
104	0	if duration.is_zero() {
105	0	Some(self)
106	0	} else if duration.is_positive() {
107	0	self.0.checked_sub(duration.unsigned_abs()).map(Self)
108		} else {
109	0	debug_assert!(duration.is_negative());
110	0	self.0.checked_add(duration.unsigned_abs()).map(Self)
111		}
112	0	}
113		// endregion checked arithmetic
114
115		/// Obtain the inner [`std::time::Instant`].
116		///
117		/// ```rust
118		/// # #![allow(deprecated)]
119		/// # use time::Instant;
120		/// let now = Instant::now();
121		/// assert_eq!(now.into_inner(), now.0);
122		/// ```
123	0	pub const fn into_inner(self) -> StdInstant {
124	0	self.0
125	0	}
126		}
127
128		// region: trait impls
129		impl From<StdInstant> for Instant {
130	0	fn from(instant: StdInstant) -> Self {
131	0	Self(instant)
132	0	}
133		}
134
135		impl From<Instant> for StdInstant {
136	0	fn from(instant: Instant) -> Self {
137	0	instant.0
138	0	}
139		}
140
141		impl Sub for Instant {
142		type Output = Duration;
143
144		/// # Panics
145		///
146		/// This may panic if an overflow occurs.
147	0	fn sub(self, other: Self) -> Self::Output {
148	0	match self.0.cmp(&other.0) {
149	0	Ordering::Equal => Duration::ZERO,
150	0	Ordering::Greater => (self.0 - other.0)
151	0	.try_into()
152	0	.expect("overflow converting `std::time::Duration` to `time::Duration`"),
153	0	Ordering::Less => -Duration::try_from(other.0 - self.0)
154	0	.expect("overflow converting `std::time::Duration` to `time::Duration`"),
155		}
156	0	}
157		}
158
159		impl Sub<StdInstant> for Instant {
160		type Output = Duration;
161
162	0	fn sub(self, other: StdInstant) -> Self::Output {
163	0	self - Self(other)
164	0	}
165		}
166
167		impl Sub<Instant> for StdInstant {
168		type Output = Duration;
169
170	0	fn sub(self, other: Instant) -> Self::Output {
171	0	Instant(self) - other
172	0	}
173		}
174
175		impl Add<Duration> for Instant {
176		type Output = Self;
177
178		/// # Panics
179		///
180		/// This function may panic if the resulting point in time cannot be represented by the
181		/// underlying data structure.
182	0	fn add(self, duration: Duration) -> Self::Output {
183	0	if duration.is_positive() {
184	0	Self(self.0 + duration.unsigned_abs())
185	0	} else if duration.is_negative() {
186		#[allow(clippy::unchecked_duration_subtraction)]
187	0	Self(self.0 - duration.unsigned_abs())
188		} else {
189	0	debug_assert!(duration.is_zero());
190	0	self
191		}
192	0	}
193		}
194
195		impl Add<Duration> for StdInstant {
196		type Output = Self;
197
198	0	fn add(self, duration: Duration) -> Self::Output {
199	0	(Instant(self) + duration).0
200	0	}
201		}
202
203		impl Add<StdDuration> for Instant {
204		type Output = Self;
205
206	0	fn add(self, duration: StdDuration) -> Self::Output {
207	0	Self(self.0 + duration)
208	0	}
209		}
210
211		impl_add_assign!(Instant: Duration, StdDuration);
212		impl_add_assign!(StdInstant: Duration);
213
214		impl Sub<Duration> for Instant {
215		type Output = Self;
216
217		/// # Panics
218		///
219		/// This function may panic if the resulting point in time cannot be represented by the
220		/// underlying data structure.
221	0	fn sub(self, duration: Duration) -> Self::Output {
222	0	if duration.is_positive() {
223		#[allow(clippy::unchecked_duration_subtraction)]
224	0	Self(self.0 - duration.unsigned_abs())
225	0	} else if duration.is_negative() {
226	0	Self(self.0 + duration.unsigned_abs())
227		} else {
228	0	debug_assert!(duration.is_zero());
229	0	self
230		}
231	0	}
232		}
233
234		impl Sub<Duration> for StdInstant {
235		type Output = Self;
236
237	0	fn sub(self, duration: Duration) -> Self::Output {
238	0	(Instant(self) - duration).0
239	0	}
240		}
241
242		impl Sub<StdDuration> for Instant {
243		type Output = Self;
244
245		/// # Panics
246		///
247		/// This function may panic if the resulting point in time cannot be represented by the
248		/// underlying data structure.
249	0	fn sub(self, duration: StdDuration) -> Self::Output {
250	0	#[allow(clippy::unchecked_duration_subtraction)]
251	0	Self(self.0 - duration)
252	0	}
253		}
254
255		impl_sub_assign!(Instant: Duration, StdDuration);
256		impl_sub_assign!(StdInstant: Duration);
257
258		impl PartialEq<StdInstant> for Instant {
259	0	fn eq(&self, rhs: &StdInstant) -> bool {
260	0	self.0.eq(rhs)
261	0	}
262		}
263
264		impl PartialEq<Instant> for StdInstant {
265	0	fn eq(&self, rhs: &Instant) -> bool {
266	0	self.eq(&rhs.0)
267	0	}
268		}
269
270		impl PartialOrd<StdInstant> for Instant {
271	0	fn partial_cmp(&self, rhs: &StdInstant) -> Option<Ordering> {
272	0	self.0.partial_cmp(rhs)
273	0	}
274		}
275
276		impl PartialOrd<Instant> for StdInstant {
277	0	fn partial_cmp(&self, rhs: &Instant) -> Option<Ordering> {
278	0	self.partial_cmp(&rhs.0)
279	0	}
280		}
281
282		impl AsRef<StdInstant> for Instant {
283	0	fn as_ref(&self) -> &StdInstant {
284	0	&self.0
285	0	}
286		}
287
288		impl Borrow<StdInstant> for Instant {
289	0	fn borrow(&self) -> &StdInstant {
290	0	&self.0
291	0	}
292		}
293		// endregion trait impls