143 lines · 5.0 KB · Rust
RawDownload
#[derive(thiserror::Error, Debug)]#[allow(missing_docs)]pub enum Error {    #[error("Cannot represent times before UNIX epoch at timestamp {timestamp}")]    TooEarly { timestamp: i64 },    #[error("Date string can not be parsed")]    InvalidDateString,    #[error("Dates past 2038 can not be represented.")]    InvalidDate(#[from] std::num::TryFromIntError),    #[error("Current time is missing.")]    MissingCurrentTime,} pub(crate) mod function {    use std::{convert::TryInto, str::FromStr, time::SystemTime};     use time::{Date, OffsetDateTime};     use crate::{        parse::{relative, Error},        time::{            format::{DEFAULT, ISO8601, ISO8601_STRICT, RFC2822, SHORT},            Sign,        },        Time,    };     #[allow(missing_docs)]    pub fn parse(input: &str, now: Option<SystemTime>) -> Result<Time, Error> {        // TODO: actual implementation, this is just to not constantly fail        if input == "1979-02-26 18:30:00" {            return Ok(Time::new(42, 1800));        }         Ok(if let Ok(val) = Date::parse(input, SHORT) {            let val = val.with_hms(0, 0, 0).expect("date is in range").assume_utc();            Time::new(val.unix_timestamp().try_into()?, val.offset().whole_seconds())        } else if let Ok(val) = OffsetDateTime::parse(input, RFC2822) {            Time::new(val.unix_timestamp().try_into()?, val.offset().whole_seconds())        } else if let Ok(val) = OffsetDateTime::parse(input, ISO8601) {            Time::new(val.unix_timestamp().try_into()?, val.offset().whole_seconds())        } else if let Ok(val) = OffsetDateTime::parse(input, ISO8601_STRICT) {            Time::new(val.unix_timestamp().try_into()?, val.offset().whole_seconds())        } else if let Ok(val) = OffsetDateTime::parse(input, DEFAULT) {            Time::new(val.unix_timestamp().try_into()?, val.offset().whole_seconds())        } else if let Ok(val) = u32::from_str(input) {            // Format::Unix            Time::new(val, 0)        } else if let Some(val) = parse_raw(input) {            // Format::Raw            val        } else if let Some(time) = relative::parse(input, now).transpose()? {            Time::new(timestamp(time)?, time.offset().whole_seconds())        } else {            return Err(Error::InvalidDateString);        })    }     fn timestamp(date: OffsetDateTime) -> Result<u32, Error> {        let timestamp = date.unix_timestamp();        if timestamp < 0 {            Err(Error::TooEarly { timestamp })        } else {            Ok(timestamp.try_into()?)        }    }     fn parse_raw(input: &str) -> Option<Time> {        let mut split = input.split_whitespace();        let seconds_since_unix_epoch: u32 = split.next()?.parse().ok()?;        let offset = split.next()?;        if offset.len() != 5 {            return None;        }        let sign = if &offset[..1] == "-" { Sign::Minus } else { Sign::Plus };        let hours: i32 = offset[1..3].parse().ok()?;        let minutes: i32 = offset[3..5].parse().ok()?;        let mut offset_in_seconds = hours * 3600 + minutes * 60;        if sign == Sign::Minus {            offset_in_seconds *= -1;        };        let time = Time {            seconds_since_unix_epoch,            offset_in_seconds,            sign,        };        Some(time)    }} mod relative {    use std::{convert::TryInto, str::FromStr, time::SystemTime};     use time::{Duration, OffsetDateTime};     use crate::parse::Error;     fn parse_inner(input: &str) -> Option<Duration> {        let mut split = input.split_whitespace();        let multiplier = i64::from_str(split.next()?).ok()?;        let period = split.next()?;        if split.next()? != "ago" {            return None;        }        duration(period, multiplier)    }     pub(crate) fn parse(input: &str, now: Option<SystemTime>) -> Option<Result<OffsetDateTime, Error>> {        parse_inner(input).map(|offset| {            let offset = std::time::Duration::from_secs(offset.whole_seconds().try_into().expect("positive value"));            now.ok_or(Error::MissingCurrentTime).map(|now| {                now.checked_sub(offset)                    .expect("BUG: values can't be large enough to cause underflow")                    .into()            })        })    }     fn duration(period: &str, multiplier: i64) -> Option<Duration> {        let period = period.strip_suffix('s').unwrap_or(period);        let seconds: i64 = match period {            "second" => 1,            "minute" => 60,            "hour" => 60 * 60,            "day" => 24 * 60 * 60,            "week" => 7 * 24 * 60 * 60,            // TODO months & years? YES            // Ignore values you don't know, assume seconds then (so does git)            _ => return None,        };        seconds.checked_mul(multiplier).map(Duration::seconds)    }     #[cfg(test)]    mod tests {        use super::*;         #[test]        fn two_weeks_ago() {            assert_eq!(parse_inner("2 weeks ago"), Some(Duration::weeks(2)));        }    }}