toml_datetime/
datetime.rs

1use core::fmt;
2use core::str::{self, FromStr};
3
4/// A parsed TOML datetime value
5///
6/// This structure is intended to represent the datetime primitive type that can
7/// be encoded into TOML documents. This type is a parsed version that contains
8/// all metadata internally.
9///
10/// Currently this type is intentionally conservative and only supports
11/// `to_string` as an accessor. Over time though it's intended that it'll grow
12/// more support!
13///
14/// Note that if you're using `Deserialize` to deserialize a TOML document, you
15/// can use this as a placeholder for where you're expecting a datetime to be
16/// specified.
17///
18/// Also note though that while this type implements `Serialize` and
19/// `Deserialize` it's only recommended to use this type with the TOML format,
20/// otherwise encoded in other formats it may look a little odd.
21///
22/// Depending on how the option values are used, this struct will correspond
23/// with one of the following four datetimes from the [TOML v1.0.0 spec]:
24///
25/// | `date`    | `time`    | `offset`  | TOML type          |
26/// | --------- | --------- | --------- | ------------------ |
27/// | `Some(_)` | `Some(_)` | `Some(_)` | [Offset Date-Time] |
28/// | `Some(_)` | `Some(_)` | `None`    | [Local Date-Time]  |
29/// | `Some(_)` | `None`    | `None`    | [Local Date]       |
30/// | `None`    | `Some(_)` | `None`    | [Local Time]       |
31///
32/// **1. Offset Date-Time**: If all the optional values are used, `Datetime`
33/// corresponds to an [Offset Date-Time]. From the TOML v1.0.0 spec:
34///
35/// > To unambiguously represent a specific instant in time, you may use an
36/// > RFC 3339 formatted date-time with offset.
37/// >
38/// > ```toml
39/// > odt1 = 1979-05-27T07:32:00Z
40/// > odt2 = 1979-05-27T00:32:00-07:00
41/// > odt3 = 1979-05-27T00:32:00.999999-07:00
42/// > ```
43/// >
44/// > For the sake of readability, you may replace the T delimiter between date
45/// > and time with a space character (as permitted by RFC 3339 section 5.6).
46/// >
47/// > ```toml
48/// > odt4 = 1979-05-27 07:32:00Z
49/// > ```
50///
51/// **2. Local Date-Time**: If `date` and `time` are given but `offset` is
52/// `None`, `Datetime` corresponds to a [Local Date-Time]. From the spec:
53///
54/// > If you omit the offset from an RFC 3339 formatted date-time, it will
55/// > represent the given date-time without any relation to an offset or
56/// > timezone. It cannot be converted to an instant in time without additional
57/// > information. Conversion to an instant, if required, is implementation-
58/// > specific.
59/// >
60/// > ```toml
61/// > ldt1 = 1979-05-27T07:32:00
62/// > ldt2 = 1979-05-27T00:32:00.999999
63/// > ```
64///
65/// **3. Local Date**: If only `date` is given, `Datetime` corresponds to a
66/// [Local Date]; see the docs for [`Date`].
67///
68/// **4. Local Time**: If only `time` is given, `Datetime` corresponds to a
69/// [Local Time]; see the docs for [`Time`].
70///
71/// [TOML v1.0.0 spec]: https://toml.io/en/v1.0.0
72/// [Offset Date-Time]: https://toml.io/en/v1.0.0#offset-date-time
73/// [Local Date-Time]: https://toml.io/en/v1.0.0#local-date-time
74/// [Local Date]: https://toml.io/en/v1.0.0#local-date
75/// [Local Time]: https://toml.io/en/v1.0.0#local-time
76#[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone, Debug)]
77pub struct Datetime {
78    /// Optional date.
79    /// Required for: *Offset Date-Time*, *Local Date-Time*, *Local Date*.
80    pub date: Option<Date>,
81
82    /// Optional time.
83    /// Required for: *Offset Date-Time*, *Local Date-Time*, *Local Time*.
84    pub time: Option<Time>,
85
86    /// Optional offset.
87    /// Required for: *Offset Date-Time*.
88    pub offset: Option<Offset>,
89}
90
91// Currently serde itself doesn't have a datetime type, so we map our `Datetime`
92// to a special value in the serde data model. Namely one with these special
93// fields/struct names.
94//
95// In general the TOML encoder/decoder will catch this and not literally emit
96// these strings but rather emit datetimes as they're intended.
97#[cfg(feature = "serde")]
98pub(crate) const FIELD: &str = "$__toml_private_datetime";
99#[cfg(feature = "serde")]
100pub(crate) const NAME: &str = "$__toml_private_Datetime";
101#[cfg(feature = "serde")]
102pub(crate) fn is_datetime(name: &'static str) -> bool {
103    name == NAME
104}
105
106/// A parsed TOML date value
107///
108/// May be part of a [`Datetime`]. Alone, `Date` corresponds to a [Local Date].
109/// From the TOML v1.0.0 spec:
110///
111/// > If you include only the date portion of an RFC 3339 formatted date-time,
112/// > it will represent that entire day without any relation to an offset or
113/// > timezone.
114/// >
115/// > ```toml
116/// > ld1 = 1979-05-27
117/// > ```
118///
119/// [Local Date]: https://toml.io/en/v1.0.0#local-date
120#[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone, Debug)]
121pub struct Date {
122    /// Year: four digits
123    pub year: u16,
124    /// Month: 1 to 12
125    pub month: u8,
126    /// Day: 1 to {28, 29, 30, 31} (based on month/year)
127    pub day: u8,
128}
129
130/// A parsed TOML time value
131///
132/// May be part of a [`Datetime`]. Alone, `Time` corresponds to a [Local Time].
133/// From the TOML v1.0.0 spec:
134///
135/// > If you include only the time portion of an RFC 3339 formatted date-time,
136/// > it will represent that time of day without any relation to a specific
137/// > day or any offset or timezone.
138/// >
139/// > ```toml
140/// > lt1 = 07:32:00
141/// > lt2 = 00:32:00.999999
142/// > ```
143/// >
144/// > Millisecond precision is required. Further precision of fractional
145/// > seconds is implementation-specific. If the value contains greater
146/// > precision than the implementation can support, the additional precision
147/// > must be truncated, not rounded.
148///
149/// [Local Time]: https://toml.io/en/v1.0.0#local-time
150#[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone, Debug)]
151pub struct Time {
152    /// Hour: 0 to 23
153    pub hour: u8,
154    /// Minute: 0 to 59
155    pub minute: u8,
156    /// Second: 0 to {58, 59, 60} (based on leap second rules)
157    pub second: u8,
158    /// Nanosecond: 0 to `999_999_999`
159    pub nanosecond: u32,
160}
161
162/// A parsed TOML time offset
163///
164#[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone, Debug)]
165pub enum Offset {
166    /// > A suffix which, when applied to a time, denotes a UTC offset of 00:00;
167    /// > often spoken "Zulu" from the ICAO phonetic alphabet representation of
168    /// > the letter "Z". --- [RFC 3339 section 2]
169    ///
170    /// [RFC 3339 section 2]: https://datatracker.ietf.org/doc/html/rfc3339#section-2
171    Z,
172
173    /// Offset between local time and UTC
174    Custom {
175        /// Minutes: -`1_440..1_440`
176        minutes: i16,
177    },
178}
179
180impl Datetime {
181    #[cfg(feature = "serde")]
182    fn type_name(&self) -> &'static str {
183        match (
184            self.date.is_some(),
185            self.time.is_some(),
186            self.offset.is_some(),
187        ) {
188            (true, true, true) => "offset datetime",
189            (true, true, false) => "local datetime",
190            (true, false, false) => Date::type_name(),
191            (false, true, false) => Time::type_name(),
192            _ => unreachable!("unsupported datetime combination"),
193        }
194    }
195}
196
197impl Date {
198    #[cfg(feature = "serde")]
199    fn type_name() -> &'static str {
200        "local date"
201    }
202}
203
204impl Time {
205    #[cfg(feature = "serde")]
206    fn type_name() -> &'static str {
207        "local time"
208    }
209}
210
211impl From<Date> for Datetime {
212    fn from(other: Date) -> Self {
213        Self {
214            date: Some(other),
215            time: None,
216            offset: None,
217        }
218    }
219}
220
221impl From<Time> for Datetime {
222    fn from(other: Time) -> Self {
223        Self {
224            date: None,
225            time: Some(other),
226            offset: None,
227        }
228    }
229}
230
231#[cfg(feature = "alloc")]
232impl fmt::Display for Datetime {
233    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
234        if let Some(ref date) = self.date {
235            write!(f, "{date}")?;
236        }
237        if let Some(ref time) = self.time {
238            if self.date.is_some() {
239                write!(f, "T")?;
240            }
241            write!(f, "{time}")?;
242        }
243        if let Some(ref offset) = self.offset {
244            write!(f, "{offset}")?;
245        }
246        Ok(())
247    }
248}
249
250impl fmt::Display for Date {
251    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
252        write!(f, "{:04}-{:02}-{:02}", self.year, self.month, self.day)
253    }
254}
255
256#[cfg(feature = "alloc")]
257impl fmt::Display for Time {
258    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
259        write!(f, "{:02}:{:02}:{:02}", self.hour, self.minute, self.second)?;
260        if self.nanosecond != 0 {
261            let s = alloc::format!("{:09}", self.nanosecond);
262            write!(f, ".{}", s.trim_end_matches('0'))?;
263        }
264        Ok(())
265    }
266}
267
268impl fmt::Display for Offset {
269    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
270        match *self {
271            Self::Z => write!(f, "Z"),
272            Self::Custom { mut minutes } => {
273                let mut sign = '+';
274                if minutes < 0 {
275                    minutes *= -1;
276                    sign = '-';
277                }
278                let hours = minutes / 60;
279                let minutes = minutes % 60;
280                write!(f, "{sign}{hours:02}:{minutes:02}")
281            }
282        }
283    }
284}
285
286impl FromStr for Datetime {
287    type Err = DatetimeParseError;
288
289    fn from_str(date: &str) -> Result<Self, DatetimeParseError> {
290        // Accepted formats:
291        //
292        // 0000-00-00T00:00:00.00Z
293        // 0000-00-00T00:00:00.00
294        // 0000-00-00
295        // 00:00:00.00
296        //
297        // ```abnf
298        // ;; Date and Time (as defined in RFC 3339)
299        //
300        // date-time      = offset-date-time / local-date-time / local-date / local-time
301        //
302        // date-fullyear  = 4DIGIT
303        // date-month     = 2DIGIT  ; 01-12
304        // date-mday      = 2DIGIT  ; 01-28, 01-29, 01-30, 01-31 based on month/year
305        // time-delim     = "T" / %x20 ; T, t, or space
306        // time-hour      = 2DIGIT  ; 00-23
307        // time-minute    = 2DIGIT  ; 00-59
308        // time-second    = 2DIGIT  ; 00-58, 00-59, 00-60 based on leap second rules
309        // time-secfrac   = "." 1*DIGIT
310        // time-numoffset = ( "+" / "-" ) time-hour ":" time-minute
311        // time-offset    = "Z" / time-numoffset
312        //
313        // partial-time   = time-hour ":" time-minute ":" time-second [ time-secfrac ]
314        // full-date      = date-fullyear "-" date-month "-" date-mday
315        // full-time      = partial-time time-offset
316        //
317        // ;; Offset Date-Time
318        //
319        // offset-date-time = full-date time-delim full-time
320        //
321        // ;; Local Date-Time
322        //
323        // local-date-time = full-date time-delim partial-time
324        //
325        // ;; Local Date
326        //
327        // local-date = full-date
328        //
329        // ;; Local Time
330        //
331        // local-time = partial-time
332        // ```
333        let mut result = Self {
334            date: None,
335            time: None,
336            offset: None,
337        };
338
339        let mut lexer = Lexer::new(date);
340
341        let digits = lexer
342            .next()
343            .ok_or(DatetimeParseError::new().expected("year or hour"))?;
344        digits
345            .is(TokenKind::Digits)
346            .map_err(|err| err.expected("year or hour"))?;
347        let sep = lexer
348            .next()
349            .ok_or(DatetimeParseError::new().expected("`-` (YYYY-MM) or `:` (HH:MM)"))?;
350        match sep.kind {
351            TokenKind::Dash => {
352                let year = digits;
353                let month = lexer
354                    .next()
355                    .ok_or_else(|| DatetimeParseError::new().what("date").expected("month"))?;
356                month
357                    .is(TokenKind::Digits)
358                    .map_err(|err| err.what("date").expected("month"))?;
359                let sep = lexer.next().ok_or(
360                    DatetimeParseError::new()
361                        .what("date")
362                        .expected("`-` (MM-DD)"),
363                )?;
364                sep.is(TokenKind::Dash)
365                    .map_err(|err| err.what("date").expected("`-` (MM-DD)"))?;
366                let day = lexer
367                    .next()
368                    .ok_or(DatetimeParseError::new().what("date").expected("day"))?;
369                day.is(TokenKind::Digits)
370                    .map_err(|err| err.what("date").expected("day"))?;
371
372                if year.raw.len() != 4 {
373                    return Err(DatetimeParseError::new()
374                        .what("date")
375                        .expected("a four-digit year (YYYY)"));
376                }
377                if month.raw.len() != 2 {
378                    return Err(DatetimeParseError::new()
379                        .what("date")
380                        .expected("a two-digit month (MM)"));
381                }
382                if day.raw.len() != 2 {
383                    return Err(DatetimeParseError::new()
384                        .what("date")
385                        .expected("a two-digit day (DD)"));
386                }
387                let date = Date {
388                    year: year.raw.parse().map_err(|_err| DatetimeParseError::new())?,
389                    month: month
390                        .raw
391                        .parse()
392                        .map_err(|_err| DatetimeParseError::new())?,
393                    day: day.raw.parse().map_err(|_err| DatetimeParseError::new())?,
394                };
395                if date.month < 1 || date.month > 12 {
396                    return Err(DatetimeParseError::new()
397                        .what("date")
398                        .expected("month between 01 and 12"));
399                }
400                let is_leap_year =
401                    (date.year % 4 == 0) && ((date.year % 100 != 0) || (date.year % 400 == 0));
402                let (max_days_in_month, expected_day) = match date.month {
403                    2 if is_leap_year => (29, "day between 01 and 29"),
404                    2 => (28, "day between 01 and 28"),
405                    4 | 6 | 9 | 11 => (30, "day between 01 and 30"),
406                    _ => (31, "day between 01 and 31"),
407                };
408                if date.day < 1 || date.day > max_days_in_month {
409                    return Err(DatetimeParseError::new()
410                        .what("date")
411                        .expected(expected_day));
412                }
413
414                result.date = Some(date);
415            }
416            TokenKind::Colon => lexer = Lexer::new(date),
417            _ => {
418                return Err(DatetimeParseError::new().expected("`-` (YYYY-MM) or `:` (HH:MM)"));
419            }
420        }
421
422        // Next parse the "partial-time" if available
423        let partial_time = if result.date.is_some() {
424            let sep = lexer.next();
425            match sep {
426                Some(token) if matches!(token.kind, TokenKind::T | TokenKind::Space) => true,
427                Some(_token) => {
428                    return Err(DatetimeParseError::new()
429                        .what("date-time")
430                        .expected("`T` between date and time"));
431                }
432                None => false,
433            }
434        } else {
435            result.date.is_none()
436        };
437
438        if partial_time {
439            let hour = lexer
440                .next()
441                .ok_or_else(|| DatetimeParseError::new().what("time").expected("hour"))?;
442            hour.is(TokenKind::Digits)
443                .map_err(|err| err.what("time").expected("hour"))?;
444            let sep = lexer.next().ok_or(
445                DatetimeParseError::new()
446                    .what("time")
447                    .expected("`:` (HH:MM)"),
448            )?;
449            sep.is(TokenKind::Colon)
450                .map_err(|err| err.what("time").expected("`:` (HH:MM)"))?;
451            let minute = lexer
452                .next()
453                .ok_or(DatetimeParseError::new().what("time").expected("minute"))?;
454            minute
455                .is(TokenKind::Digits)
456                .map_err(|err| err.what("time").expected("minute"))?;
457            let sep = lexer.next().ok_or(
458                DatetimeParseError::new()
459                    .what("time")
460                    .expected("`:` (MM:SS)"),
461            )?;
462            sep.is(TokenKind::Colon)
463                .map_err(|err| err.what("time").expected("`:` (MM:SS)"))?;
464            let second = lexer
465                .next()
466                .ok_or(DatetimeParseError::new().what("time").expected("second"))?;
467            second
468                .is(TokenKind::Digits)
469                .map_err(|err| err.what("time").expected("second"))?;
470
471            let nanosecond = if lexer.clone().next().map(|t| t.kind) == Some(TokenKind::Dot) {
472                let sep = lexer.next().ok_or(DatetimeParseError::new())?;
473                sep.is(TokenKind::Dot)?;
474                let nanosecond = lexer.next().ok_or(
475                    DatetimeParseError::new()
476                        .what("time")
477                        .expected("nanosecond"),
478                )?;
479                nanosecond
480                    .is(TokenKind::Digits)
481                    .map_err(|err| err.what("time").expected("nanosecond"))?;
482                Some(nanosecond)
483            } else {
484                None
485            };
486
487            if hour.raw.len() != 2 {
488                return Err(DatetimeParseError::new()
489                    .what("time")
490                    .expected("a two-digit hour (HH)"));
491            }
492            if minute.raw.len() != 2 {
493                return Err(DatetimeParseError::new()
494                    .what("time")
495                    .expected("a two-digit minute (MM)"));
496            }
497            if second.raw.len() != 2 {
498                return Err(DatetimeParseError::new()
499                    .what("time")
500                    .expected("a two-digit second (SS)"));
501            }
502
503            let time = Time {
504                hour: hour.raw.parse().map_err(|_err| DatetimeParseError::new())?,
505                minute: minute
506                    .raw
507                    .parse()
508                    .map_err(|_err| DatetimeParseError::new())?,
509                second: second
510                    .raw
511                    .parse()
512                    .map_err(|_err| DatetimeParseError::new())?,
513                nanosecond: nanosecond.map(|t| s_to_nanoseconds(t.raw)).unwrap_or(0),
514            };
515
516            if time.hour > 23 {
517                return Err(DatetimeParseError::new()
518                    .what("time")
519                    .expected("hour between 00 and 23"));
520            }
521            if time.minute > 59 {
522                return Err(DatetimeParseError::new()
523                    .what("time")
524                    .expected("minute between 00 and 59"));
525            }
526            // 00-58, 00-59, 00-60 based on leap second rules
527            if time.second > 60 {
528                return Err(DatetimeParseError::new()
529                    .what("time")
530                    .expected("second between 00 and 60"));
531            }
532            if time.nanosecond > 999_999_999 {
533                return Err(DatetimeParseError::new()
534                    .what("time")
535                    .expected("nanoseconds overflowed"));
536            }
537
538            result.time = Some(time);
539        }
540
541        // And finally, parse the offset
542        if result.date.is_some() && result.time.is_some() {
543            match lexer.next() {
544                Some(token) if token.kind == TokenKind::Z => {
545                    result.offset = Some(Offset::Z);
546                }
547                Some(token) if matches!(token.kind, TokenKind::Plus | TokenKind::Dash) => {
548                    let sign = if token.kind == TokenKind::Plus { 1 } else { -1 };
549                    let hours = lexer
550                        .next()
551                        .ok_or(DatetimeParseError::new().what("offset").expected("hour"))?;
552                    hours
553                        .is(TokenKind::Digits)
554                        .map_err(|err| err.what("offset").expected("hour"))?;
555                    let sep = lexer.next().ok_or(
556                        DatetimeParseError::new()
557                            .what("offset")
558                            .expected("`:` (HH:MM)"),
559                    )?;
560                    sep.is(TokenKind::Colon)
561                        .map_err(|err| err.what("offset").expected("`:` (HH:MM)"))?;
562                    let minutes = lexer
563                        .next()
564                        .ok_or(DatetimeParseError::new().what("offset").expected("minute"))?;
565                    minutes
566                        .is(TokenKind::Digits)
567                        .map_err(|err| err.what("offset").expected("minute"))?;
568
569                    if hours.raw.len() != 2 {
570                        return Err(DatetimeParseError::new()
571                            .what("offset")
572                            .expected("a two-digit hour (HH)"));
573                    }
574                    if minutes.raw.len() != 2 {
575                        return Err(DatetimeParseError::new()
576                            .what("offset")
577                            .expected("a two-digit minute (MM)"));
578                    }
579
580                    let hours = hours
581                        .raw
582                        .parse::<u8>()
583                        .map_err(|_err| DatetimeParseError::new())?;
584                    let minutes = minutes
585                        .raw
586                        .parse::<u8>()
587                        .map_err(|_err| DatetimeParseError::new())?;
588
589                    if hours > 23 {
590                        return Err(DatetimeParseError::new()
591                            .what("offset")
592                            .expected("hours between 00 and 23"));
593                    }
594                    if minutes > 59 {
595                        return Err(DatetimeParseError::new()
596                            .what("offset")
597                            .expected("minutes between 00 and 59"));
598                    }
599
600                    let total_minutes = sign * (hours as i16 * 60 + minutes as i16);
601
602                    if !((-24 * 60)..=(24 * 60)).contains(&total_minutes) {
603                        return Err(DatetimeParseError::new().what("offset"));
604                    }
605
606                    result.offset = Some(Offset::Custom {
607                        minutes: total_minutes,
608                    });
609                }
610                Some(_token) => {
611                    return Err(DatetimeParseError::new()
612                        .what("offset")
613                        .expected("`Z`, +OFFSET, -OFFSET"));
614                }
615                None => {}
616            }
617        }
618
619        // Return an error if we didn't hit eof, otherwise return our parsed
620        // date
621        if lexer.unknown().is_some() {
622            return Err(DatetimeParseError::new());
623        }
624
625        Ok(result)
626    }
627}
628
629fn s_to_nanoseconds(input: &str) -> u32 {
630    let mut nanosecond = 0;
631    for (i, byte) in input.bytes().enumerate() {
632        if byte.is_ascii_digit() {
633            if i < 9 {
634                let p = 10_u32.pow(8 - i as u32);
635                nanosecond += p * u32::from(byte - b'0');
636            }
637        } else {
638            panic!("invalid nanoseconds {input:?}");
639        }
640    }
641    nanosecond
642}
643
644#[derive(Copy, Clone)]
645struct Token<'s> {
646    kind: TokenKind,
647    raw: &'s str,
648}
649
650impl Token<'_> {
651    fn is(&self, kind: TokenKind) -> Result<(), DatetimeParseError> {
652        if self.kind == kind {
653            Ok(())
654        } else {
655            Err(DatetimeParseError::new())
656        }
657    }
658}
659
660#[derive(Copy, Clone, PartialEq, Eq)]
661enum TokenKind {
662    Digits,
663    Dash,
664    Colon,
665    Dot,
666    T,
667    Space,
668    Z,
669    Plus,
670    Unknown,
671}
672
673#[derive(Copy, Clone)]
674struct Lexer<'s> {
675    stream: &'s str,
676}
677
678impl<'s> Lexer<'s> {
679    fn new(input: &'s str) -> Self {
680        Self { stream: input }
681    }
682
683    fn unknown(&mut self) -> Option<Token<'s>> {
684        let remaining = self.stream.len();
685        if remaining == 0 {
686            return None;
687        }
688        let raw = self.stream;
689        self.stream = &self.stream[remaining..remaining];
690        Some(Token {
691            kind: TokenKind::Unknown,
692            raw,
693        })
694    }
695}
696
697impl<'s> Iterator for Lexer<'s> {
698    type Item = Token<'s>;
699
700    fn next(&mut self) -> Option<Self::Item> {
701        let (kind, end) = match self.stream.as_bytes().first()? {
702            b'0'..=b'9' => {
703                let end = self
704                    .stream
705                    .as_bytes()
706                    .iter()
707                    .position(|b| !b.is_ascii_digit())
708                    .unwrap_or(self.stream.len());
709                (TokenKind::Digits, end)
710            }
711            b'-' => (TokenKind::Dash, 1),
712            b':' => (TokenKind::Colon, 1),
713            b'T' | b't' => (TokenKind::T, 1),
714            b' ' => (TokenKind::Space, 1),
715            b'Z' | b'z' => (TokenKind::Z, 1),
716            b'+' => (TokenKind::Plus, 1),
717            b'.' => (TokenKind::Dot, 1),
718            _ => (TokenKind::Unknown, self.stream.len()),
719        };
720        let (raw, rest) = self.stream.split_at(end);
721        self.stream = rest;
722        Some(Token { kind, raw })
723    }
724}
725
726/// Error returned from parsing a `Datetime` in the `FromStr` implementation.
727#[derive(Debug, Clone)]
728#[non_exhaustive]
729pub struct DatetimeParseError {
730    what: Option<&'static str>,
731    expected: Option<&'static str>,
732}
733
734impl DatetimeParseError {
735    fn new() -> Self {
736        Self {
737            what: None,
738            expected: None,
739        }
740    }
741    fn what(mut self, what: &'static str) -> Self {
742        self.what = Some(what);
743        self
744    }
745    fn expected(mut self, expected: &'static str) -> Self {
746        self.expected = Some(expected);
747        self
748    }
749}
750
751impl fmt::Display for DatetimeParseError {
752    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
753        if let Some(what) = self.what {
754            write!(f, "invalid {what}")?;
755        } else {
756            "invalid datetime".fmt(f)?;
757        }
758        if let Some(expected) = self.expected {
759            write!(f, ", expected {expected}")?;
760        }
761        Ok(())
762    }
763}
764
765#[cfg(feature = "std")]
766impl std::error::Error for DatetimeParseError {}
767#[cfg(all(not(feature = "std"), feature = "serde"))]
768impl serde::de::StdError for DatetimeParseError {}
769
770#[cfg(feature = "serde")]
771#[cfg(feature = "alloc")]
772impl serde::ser::Serialize for Datetime {
773    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
774    where
775        S: serde::ser::Serializer,
776    {
777        use crate::alloc::string::ToString as _;
778        use serde::ser::SerializeStruct;
779
780        let mut s = serializer.serialize_struct(NAME, 1)?;
781        s.serialize_field(FIELD, &self.to_string())?;
782        s.end()
783    }
784}
785
786#[cfg(feature = "serde")]
787#[cfg(feature = "alloc")]
788impl serde::ser::Serialize for Date {
789    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
790    where
791        S: serde::ser::Serializer,
792    {
793        Datetime::from(*self).serialize(serializer)
794    }
795}
796
797#[cfg(feature = "serde")]
798#[cfg(feature = "alloc")]
799impl serde::ser::Serialize for Time {
800    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
801    where
802        S: serde::ser::Serializer,
803    {
804        Datetime::from(*self).serialize(serializer)
805    }
806}
807
808#[cfg(feature = "serde")]
809impl<'de> serde::de::Deserialize<'de> for Datetime {
810    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
811    where
812        D: serde::de::Deserializer<'de>,
813    {
814        struct DatetimeVisitor;
815
816        impl<'de> serde::de::Visitor<'de> for DatetimeVisitor {
817            type Value = Datetime;
818
819            fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
820                formatter.write_str("a TOML datetime")
821            }
822
823            fn visit_map<V>(self, mut visitor: V) -> Result<Datetime, V::Error>
824            where
825                V: serde::de::MapAccess<'de>,
826            {
827                let value = visitor.next_key::<DatetimeKey>()?;
828                if value.is_none() {
829                    return Err(serde::de::Error::custom("datetime key not found"));
830                }
831                let v: DatetimeFromString = visitor.next_value()?;
832                Ok(v.value)
833            }
834        }
835
836        static FIELDS: [&str; 1] = [FIELD];
837        deserializer.deserialize_struct(NAME, &FIELDS, DatetimeVisitor)
838    }
839}
840
841#[cfg(feature = "serde")]
842impl<'de> serde::de::Deserialize<'de> for Date {
843    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
844    where
845        D: serde::de::Deserializer<'de>,
846    {
847        match Datetime::deserialize(deserializer)? {
848            Datetime {
849                date: Some(date),
850                time: None,
851                offset: None,
852            } => Ok(date),
853            datetime => Err(serde::de::Error::invalid_type(
854                serde::de::Unexpected::Other(datetime.type_name()),
855                &Self::type_name(),
856            )),
857        }
858    }
859}
860
861#[cfg(feature = "serde")]
862impl<'de> serde::de::Deserialize<'de> for Time {
863    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
864    where
865        D: serde::de::Deserializer<'de>,
866    {
867        match Datetime::deserialize(deserializer)? {
868            Datetime {
869                date: None,
870                time: Some(time),
871                offset: None,
872            } => Ok(time),
873            datetime => Err(serde::de::Error::invalid_type(
874                serde::de::Unexpected::Other(datetime.type_name()),
875                &Self::type_name(),
876            )),
877        }
878    }
879}
880
881#[cfg(feature = "serde")]
882struct DatetimeKey;
883
884#[cfg(feature = "serde")]
885impl<'de> serde::de::Deserialize<'de> for DatetimeKey {
886    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
887    where
888        D: serde::de::Deserializer<'de>,
889    {
890        struct FieldVisitor;
891
892        impl serde::de::Visitor<'_> for FieldVisitor {
893            type Value = ();
894
895            fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
896                formatter.write_str("a valid datetime field")
897            }
898
899            fn visit_str<E>(self, s: &str) -> Result<(), E>
900            where
901                E: serde::de::Error,
902            {
903                if s == FIELD {
904                    Ok(())
905                } else {
906                    Err(serde::de::Error::custom("expected field with custom name"))
907                }
908            }
909        }
910
911        deserializer.deserialize_identifier(FieldVisitor)?;
912        Ok(Self)
913    }
914}
915
916#[cfg(feature = "serde")]
917pub(crate) struct DatetimeFromString {
918    pub(crate) value: Datetime,
919}
920
921#[cfg(feature = "serde")]
922impl<'de> serde::de::Deserialize<'de> for DatetimeFromString {
923    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
924    where
925        D: serde::de::Deserializer<'de>,
926    {
927        struct Visitor;
928
929        impl serde::de::Visitor<'_> for Visitor {
930            type Value = DatetimeFromString;
931
932            fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
933                formatter.write_str("string containing a datetime")
934            }
935
936            fn visit_str<E>(self, s: &str) -> Result<DatetimeFromString, E>
937            where
938                E: serde::de::Error,
939            {
940                match s.parse() {
941                    Ok(date) => Ok(DatetimeFromString { value: date }),
942                    Err(e) => Err(serde::de::Error::custom(e)),
943                }
944            }
945        }
946
947        deserializer.deserialize_str(Visitor)
948    }
949}