proto-types 0.2.2

// Most of the content of this file is taken from (prost-types)[https://github.com/tokio-rs/prost/blob/master/prost-types/src], licensed under the Apache-2.0 license.
// Modifications have been applied to make casting operations more explicit.

#[cfg(feature = "serde")]
mod serde;

mod timestamp_conversions;
mod timestamp_impls;
mod timestamp_operations;

use super::*;
use crate::{
	Timestamp,
	constants::{NANOS_PER_SECOND, PACKAGE_PREFIX},
	datetime_internal::DateTime,
};

impl Timestamp {
	/// Normalizes the timestamp to a canonical format.
	///
	/// Based on [`google::protobuf::util::CreateNormalized`][1].
	///
	/// [1]: https://github.com/google/protobuf/blob/v3.3.2/src/google/protobuf/util/time_util.cc#L59-L77
	pub fn normalize(&mut self) {
		// Make sure nanos is in the range.
		if self.nanos <= -NANOS_PER_SECOND || self.nanos >= NANOS_PER_SECOND {
			if let Some(seconds) = self
				.seconds
				.checked_add(i64::from(self.nanos / NANOS_PER_SECOND))
			{
				self.seconds = seconds;

				self.nanos %= NANOS_PER_SECOND;
			} else if self.nanos < 0 {
				// Negative overflow! Set to the earliest normal value.

				self.seconds = i64::MIN;

				self.nanos = 0;
			} else {
				// Positive overflow! Set to the latest normal value.

				self.seconds = i64::MAX;

				self.nanos = 999_999_999;
			}
		}

		// For Timestamp nanos should be in the range [0, 999999999].

		if self.nanos < 0 {
			if let Some(seconds) = self.seconds.checked_sub(1) {
				self.seconds = seconds;

				self.nanos += NANOS_PER_SECOND;
			} else {
				// Negative overflow! Set to the earliest normal value.

				debug_assert_eq!(self.seconds, i64::MIN);

				self.nanos = 0;
			}
		}

		// TODO: should this be checked?

		// debug_assert!(self.seconds >= -62_135_596_800 && self.seconds <= 253_402_300_799,

		//               "invalid timestamp: {:?}", self);
	}

	/// Normalizes the timestamp to a canonical format, returning the original value if it cannot be
	/// normalized.
	///
	/// Normalization is based on [`google::protobuf::util::CreateNormalized`][1].
	///
	/// [1]: https://github.com/google/protobuf/blob/v3.3.2/src/google/protobuf/util/time_util.cc#L59-L77
	pub fn try_normalize(mut self) -> Result<Self, Self> {
		let before = self;

		self.normalize();

		// If the seconds value has changed, and is either i64::MIN or i64::MAX, then the timestamp

		// normalization overflowed.

		if (self.seconds == i64::MAX || self.seconds == i64::MIN) && self.seconds != before.seconds
		{
			Err(before)
		} else {
			Ok(self)
		}
	}

	/// Return a normalized copy of the timestamp to a canonical format.
	///
	/// Based on [`google::protobuf::util::CreateNormalized`][1].
	///
	/// [1]: https://github.com/google/protobuf/blob/v3.3.2/src/google/protobuf/util/time_util.cc#L59-L77
	#[must_use]
	#[inline]
	pub fn normalized(&self) -> Self {
		let mut result = *self;

		result.normalize();

		result
	}

	#[inline]
	/// Creates a new `Timestamp` at the start of the provided UTC date.
	pub fn date(year: i64, month: u8, day: u8) -> Result<Self, TimestampError> {
		Self::date_time_nanos(year, month, day, 0, 0, 0, 0)
	}

	#[inline]
	/// Creates a new `Timestamp` instance with the provided UTC date and time.
	pub fn date_time(
		year: i64,

		month: u8,

		day: u8,

		hour: u8,

		minute: u8,

		second: u8,
	) -> Result<Self, TimestampError> {
		Self::date_time_nanos(year, month, day, hour, minute, second, 0)
	}

	#[inline]
	/// Creates a new `Timestamp` instance with the provided UTC date and time.
	pub fn date_time_nanos(
		year: i64,

		month: u8,

		day: u8,

		hour: u8,

		minute: u8,

		second: u8,

		nanos: u32,
	) -> Result<Self, TimestampError> {
		let date_time = DateTime {
			year,

			month,

			day,

			hour,

			minute,

			second,

			nanos,
		};

		Self::try_from(date_time)
	}
}

impl Name for Timestamp {
	const PACKAGE: &'static str = PACKAGE_PREFIX;

	const NAME: &'static str = "Timestamp";

	fn type_url() -> String {
		type_url_for::<Self>()
	}
}

#[cfg(feature = "std")]
impl From<std::time::SystemTime> for Timestamp {
	fn from(system_time: std::time::SystemTime) -> Self {
		let (seconds, nanos) = match system_time.duration_since(std::time::UNIX_EPOCH) {
			Ok(duration) => {
				let seconds = i64::try_from(duration.as_secs()).unwrap_or_default();

				// SAFETY: Safe due to the standard library's implementation
				(seconds, duration.subsec_nanos().cast_signed())
			}

			Err(error) => {
				let duration = error.duration();

				let seconds = i64::try_from(duration.as_secs()).unwrap_or_default();

				// SAFETY: Safe due to the standard library's implementation
				let nanos = duration.subsec_nanos().cast_signed();

				if nanos == 0 {
					(-seconds, 0)
				} else {
					(-seconds - 1, 1_000_000_000 - nanos)
				}
			}
		};

		Self { seconds, nanos }
	}
}

/// A timestamp handling error.
#[derive(Debug, PartialEq, Eq, Clone)]
#[non_exhaustive]
pub enum TimestampError {
	/// Indicates that a [`Timestamp`] could not be converted to
	/// [`SystemTime`][std::time::SystemTime] because it is out of range.
	///
	/// The range of times that can be represented by `SystemTime` depends on the platform. All
	/// `Timestamp`s are likely representable on 64-bit Unix-like platforms, but other platforms,
	/// such as Windows and 32-bit Linux, may not be able to represent the full range of
	/// `Timestamp`s.
	OutOfSystemRange(Timestamp),
	/// An error indicating failure to parse a timestamp in RFC-3339 format.
	ParseFailure,
	/// Indicates an error when constructing a timestamp due to invalid date or time data.
	InvalidDateTime,
}

impl fmt::Display for TimestampError {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
		match self {
			Self::OutOfSystemRange(timestamp) => {
				write!(
					f,
					"{timestamp} is not representable as a `SystemTime` because it is out of range"
				)
			}

			Self::ParseFailure => {
				write!(f, "failed to parse RFC-3339 formatted timestamp")
			}

			Self::InvalidDateTime => {
				write!(f, "invalid date or time")
			}
		}
	}
}

impl core::error::Error for TimestampError {}

#[cfg(feature = "std")]
impl TryFrom<Timestamp> for std::time::SystemTime {
	type Error = TimestampError;

	fn try_from(mut timestamp: Timestamp) -> Result<Self, Self::Error> {
		let orig_timestamp = timestamp;

		timestamp.normalize();

		let system_time = if timestamp.seconds >= 0 {
			std::time::UNIX_EPOCH.checked_add(time::Duration::from_secs(
				timestamp
					.seconds
					.try_into()
					.map_err(|_| TimestampError::OutOfSystemRange(timestamp))?,
			))
		} else {
			std::time::UNIX_EPOCH.checked_sub(time::Duration::from_secs(
				timestamp
					.seconds
					.checked_neg()
					.and_then(|s| s.try_into().ok())
					.ok_or(TimestampError::OutOfSystemRange(timestamp))?,
			))
		};

		let system_time = system_time
			.map(|time| {
				let nanos = u64::try_from(timestamp.nanos)
					.map_err(|_| TimestampError::OutOfSystemRange(timestamp))?;

				time.checked_add(core::time::Duration::from_nanos(nanos))
					.ok_or(TimestampError::OutOfSystemRange(timestamp))
			})
			.transpose()?;

		system_time.ok_or(TimestampError::OutOfSystemRange(orig_timestamp))
	}
}

impl FromStr for Timestamp {
	type Err = TimestampError;

	fn from_str(s: &str) -> Result<Self, TimestampError> {
		datetime_internal::parse_timestamp(s).ok_or(TimestampError::ParseFailure)
	}
}

impl fmt::Display for Timestamp {
	fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
		core::fmt::Display::fmt(&DateTime::from(*self), f)
	}
}