1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
// This is a part of Chrono.
// See README.md and LICENSE.txt for details.

//! The time zone, which calculates offsets from the local time to UTC.
//!
//! There are four operations provided by the `TimeZone` trait:
//!
//! 1. Converting the local `NaiveDateTime` to `DateTime<Tz>`
//! 2. Converting the UTC `NaiveDateTime` to `DateTime<Tz>`
//! 3. Converting `DateTime<Tz>` to the local `NaiveDateTime`
//! 4. Constructing `DateTime<Tz>` objects from various offsets
//!
//! 1 is used for constructors. 2 is used for the `with_timezone` method of date and time types.
//! 3 is used for other methods, e.g. `year()` or `format()`, and provided by an associated type
//! which implements `Offset` (which then passed to `TimeZone` for actual implementations).
//! Technically speaking `TimeZone` has a total knowledge about given timescale,
//! but `Offset` is used as a cache to avoid the repeated conversion
//! and provides implementations for 1 and 3.
//! An `TimeZone` instance can be reconstructed from the corresponding `Offset` instance.

use core::fmt;

use format::{parse, ParseResult, Parsed, StrftimeItems};
use naive::{NaiveDate, NaiveDateTime, NaiveTime};
use Weekday;
use {Date, DateTime};

/// The conversion result from the local time to the timezone-aware datetime types.
#[derive(Clone, PartialEq, Debug, Copy, Eq, Hash)]
pub enum LocalResult<T> {
    /// Given local time representation is invalid.
    /// This can occur when, for example, the positive timezone transition.
    None,
    /// Given local time representation has a single unique result.
    Single(T),
    /// Given local time representation has multiple results and thus ambiguous.
    /// This can occur when, for example, the negative timezone transition.
    Ambiguous(T /*min*/, T /*max*/),
}

impl<T> LocalResult<T> {
    /// Returns `Some` only when the conversion result is unique, or `None` otherwise.
    pub fn single(self) -> Option<T> {
        match self {
            LocalResult::Single(t) => Some(t),
            _ => None,
        }
    }

    /// Returns `Some` for the earliest possible conversion result, or `None` if none.
    pub fn earliest(self) -> Option<T> {
        match self {
            LocalResult::Single(t) | LocalResult::Ambiguous(t, _) => Some(t),
            _ => None,
        }
    }

    /// Returns `Some` for the latest possible conversion result, or `None` if none.
    pub fn latest(self) -> Option<T> {
        match self {
            LocalResult::Single(t) | LocalResult::Ambiguous(_, t) => Some(t),
            _ => None,
        }
    }

    /// Maps a `LocalResult<T>` into `LocalResult<U>` with given function.
    pub fn map<U, F: FnMut(T) -> U>(self, mut f: F) -> LocalResult<U> {
        match self {
            LocalResult::None => LocalResult::None,
            LocalResult::Single(v) => LocalResult::Single(f(v)),
            LocalResult::Ambiguous(min, max) => LocalResult::Ambiguous(f(min), f(max)),
        }
    }
}

impl<Tz: TimeZone> LocalResult<Date<Tz>> {
    /// Makes a new `DateTime` from the current date and given `NaiveTime`.
    /// The offset in the current date is preserved.
    ///
    /// Propagates any error. Ambiguous result would be discarded.
    #[inline]
    pub fn and_time(self, time: NaiveTime) -> LocalResult<DateTime<Tz>> {
        match self {
            LocalResult::Single(d) => d
                .and_time(time)
                .map_or(LocalResult::None, LocalResult::Single),
            _ => LocalResult::None,
        }
    }

    /// Makes a new `DateTime` from the current date, hour, minute and second.
    /// The offset in the current date is preserved.
    ///
    /// Propagates any error. Ambiguous result would be discarded.
    #[inline]
    pub fn and_hms_opt(self, hour: u32, min: u32, sec: u32) -> LocalResult<DateTime<Tz>> {
        match self {
            LocalResult::Single(d) => d
                .and_hms_opt(hour, min, sec)
                .map_or(LocalResult::None, LocalResult::Single),
            _ => LocalResult::None,
        }
    }

    /// Makes a new `DateTime` from the current date, hour, minute, second and millisecond.
    /// The millisecond part can exceed 1,000 in order to represent the leap second.
    /// The offset in the current date is preserved.
    ///
    /// Propagates any error. Ambiguous result would be discarded.
    #[inline]
    pub fn and_hms_milli_opt(
        self,
        hour: u32,
        min: u32,
        sec: u32,
        milli: u32,
    ) -> LocalResult<DateTime<Tz>> {
        match self {
            LocalResult::Single(d) => d
                .and_hms_milli_opt(hour, min, sec, milli)
                .map_or(LocalResult::None, LocalResult::Single),
            _ => LocalResult::None,
        }
    }

    /// Makes a new `DateTime` from the current date, hour, minute, second and microsecond.
    /// The microsecond part can exceed 1,000,000 in order to represent the leap second.
    /// The offset in the current date is preserved.
    ///
    /// Propagates any error. Ambiguous result would be discarded.
    #[inline]
    pub fn and_hms_micro_opt(
        self,
        hour: u32,
        min: u32,
        sec: u32,
        micro: u32,
    ) -> LocalResult<DateTime<Tz>> {
        match self {
            LocalResult::Single(d) => d
                .and_hms_micro_opt(hour, min, sec, micro)
                .map_or(LocalResult::None, LocalResult::Single),
            _ => LocalResult::None,
        }
    }

    /// Makes a new `DateTime` from the current date, hour, minute, second and nanosecond.
    /// The nanosecond part can exceed 1,000,000,000 in order to represent the leap second.
    /// The offset in the current date is preserved.
    ///
    /// Propagates any error. Ambiguous result would be discarded.
    #[inline]
    pub fn and_hms_nano_opt(
        self,
        hour: u32,
        min: u32,
        sec: u32,
        nano: u32,
    ) -> LocalResult<DateTime<Tz>> {
        match self {
            LocalResult::Single(d) => d
                .and_hms_nano_opt(hour, min, sec, nano)
                .map_or(LocalResult::None, LocalResult::Single),
            _ => LocalResult::None,
        }
    }
}

impl<T: fmt::Debug> LocalResult<T> {
    /// Returns the single unique conversion result, or panics accordingly.
    pub fn unwrap(self) -> T {
        match self {
            LocalResult::None => panic!("No such local time"),
            LocalResult::Single(t) => t,
            LocalResult::Ambiguous(t1, t2) => {
                panic!("Ambiguous local time, ranging from {:?} to {:?}", t1, t2)
            }
        }
    }
}

/// The offset from the local time to UTC.
pub trait Offset: Sized + Clone + fmt::Debug {
    /// Returns the fixed offset from UTC to the local time stored.
    fn fix(&self) -> FixedOffset;
}

/// The time zone.
///
/// The methods here are the primarily constructors for [`Date`](../struct.Date.html) and
/// [`DateTime`](../struct.DateTime.html) types.
pub trait TimeZone: Sized + Clone {
    /// An associated offset type.
    /// This type is used to store the actual offset in date and time types.
    /// The original `TimeZone` value can be recovered via `TimeZone::from_offset`.
    type Offset: Offset;

    /// Makes a new `Date` from year, month, day and the current time zone.
    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
    ///
    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
    /// but it will propagate to the `DateTime` values constructed via this date.
    ///
    /// Panics on the out-of-range date, invalid month and/or day.
    ///
    /// # Example
    ///
    /// ~~~~
    /// use chrono::{Utc, TimeZone};
    ///
    /// assert_eq!(Utc.ymd(2015, 5, 15).to_string(), "2015-05-15UTC");
    /// ~~~~
    fn ymd(&self, year: i32, month: u32, day: u32) -> Date<Self> {
        self.ymd_opt(year, month, day).unwrap()
    }

    /// Makes a new `Date` from year, month, day and the current time zone.
    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
    ///
    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
    /// but it will propagate to the `DateTime` values constructed via this date.
    ///
    /// Returns `None` on the out-of-range date, invalid month and/or day.
    ///
    /// # Example
    ///
    /// ~~~~
    /// use chrono::{Utc, LocalResult, TimeZone};
    ///
    /// assert_eq!(Utc.ymd_opt(2015, 5, 15).unwrap().to_string(), "2015-05-15UTC");
    /// assert_eq!(Utc.ymd_opt(2000, 0, 0), LocalResult::None);
    /// ~~~~
    fn ymd_opt(&self, year: i32, month: u32, day: u32) -> LocalResult<Date<Self>> {
        match NaiveDate::from_ymd_opt(year, month, day) {
            Some(d) => self.from_local_date(&d),
            None => LocalResult::None,
        }
    }

    /// Makes a new `Date` from year, day of year (DOY or "ordinal") and the current time zone.
    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
    ///
    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
    /// but it will propagate to the `DateTime` values constructed via this date.
    ///
    /// Panics on the out-of-range date and/or invalid DOY.
    ///
    /// # Example
    ///
    /// ~~~~
    /// use chrono::{Utc, TimeZone};
    ///
    /// assert_eq!(Utc.yo(2015, 135).to_string(), "2015-05-15UTC");
    /// ~~~~
    fn yo(&self, year: i32, ordinal: u32) -> Date<Self> {
        self.yo_opt(year, ordinal).unwrap()
    }

    /// Makes a new `Date` from year, day of year (DOY or "ordinal") and the current time zone.
    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
    ///
    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
    /// but it will propagate to the `DateTime` values constructed via this date.
    ///
    /// Returns `None` on the out-of-range date and/or invalid DOY.
    fn yo_opt(&self, year: i32, ordinal: u32) -> LocalResult<Date<Self>> {
        match NaiveDate::from_yo_opt(year, ordinal) {
            Some(d) => self.from_local_date(&d),
            None => LocalResult::None,
        }
    }

    /// Makes a new `Date` from ISO week date (year and week number), day of the week (DOW) and
    /// the current time zone.
    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
    /// The resulting `Date` may have a different year from the input year.
    ///
    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
    /// but it will propagate to the `DateTime` values constructed via this date.
    ///
    /// Panics on the out-of-range date and/or invalid week number.
    ///
    /// # Example
    ///
    /// ~~~~
    /// use chrono::{Utc, Weekday, TimeZone};
    ///
    /// assert_eq!(Utc.isoywd(2015, 20, Weekday::Fri).to_string(), "2015-05-15UTC");
    /// ~~~~
    fn isoywd(&self, year: i32, week: u32, weekday: Weekday) -> Date<Self> {
        self.isoywd_opt(year, week, weekday).unwrap()
    }

    /// Makes a new `Date` from ISO week date (year and week number), day of the week (DOW) and
    /// the current time zone.
    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
    /// The resulting `Date` may have a different year from the input year.
    ///
    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
    /// but it will propagate to the `DateTime` values constructed via this date.
    ///
    /// Returns `None` on the out-of-range date and/or invalid week number.
    fn isoywd_opt(&self, year: i32, week: u32, weekday: Weekday) -> LocalResult<Date<Self>> {
        match NaiveDate::from_isoywd_opt(year, week, weekday) {
            Some(d) => self.from_local_date(&d),
            None => LocalResult::None,
        }
    }

    /// Makes a new `DateTime` from the number of non-leap seconds
    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp")
    /// and the number of nanoseconds since the last whole non-leap second.
    ///
    /// Panics on the out-of-range number of seconds and/or invalid nanosecond,
    /// for a non-panicking version see [`timestamp_opt`](#method.timestamp_opt).
    ///
    /// # Example
    ///
    /// ~~~~
    /// use chrono::{Utc, TimeZone};
    ///
    /// assert_eq!(Utc.timestamp(1431648000, 0).to_string(), "2015-05-15 00:00:00 UTC");
    /// ~~~~
    fn timestamp(&self, secs: i64, nsecs: u32) -> DateTime<Self> {
        self.timestamp_opt(secs, nsecs).unwrap()
    }

    /// Makes a new `DateTime` from the number of non-leap seconds
    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp")
    /// and the number of nanoseconds since the last whole non-leap second.
    ///
    /// Returns `LocalResult::None` on out-of-range number of seconds and/or
    /// invalid nanosecond, otherwise always returns `LocalResult::Single`.
    fn timestamp_opt(&self, secs: i64, nsecs: u32) -> LocalResult<DateTime<Self>> {
        match NaiveDateTime::from_timestamp_opt(secs, nsecs) {
            Some(dt) => LocalResult::Single(self.from_utc_datetime(&dt)),
            None => LocalResult::None,
        }
    }

    /// Makes a new `DateTime` from the number of non-leap milliseconds
    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp").
    ///
    /// Panics on out-of-range number of milliseconds for a non-panicking
    /// version see [`timestamp_millis_opt`](#method.timestamp_millis_opt).
    ///
    /// # Example
    ///
    /// ~~~~
    /// use chrono::{Utc, TimeZone};
    ///
    /// assert_eq!(Utc.timestamp_millis(1431648000).timestamp(), 1431648);
    /// ~~~~
    fn timestamp_millis(&self, millis: i64) -> DateTime<Self> {
        self.timestamp_millis_opt(millis).unwrap()
    }

    /// Makes a new `DateTime` from the number of non-leap milliseconds
    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp").
    ///
    ///
    /// Returns `LocalResult::None` on out-of-range number of milliseconds
    /// and/or invalid nanosecond, otherwise always returns
    /// `LocalResult::Single`.
    ///
    /// # Example
    ///
    /// ~~~~
    /// use chrono::{Utc, TimeZone, LocalResult};
    /// match Utc.timestamp_millis_opt(1431648000) {
    ///     LocalResult::Single(dt) => assert_eq!(dt.timestamp(), 1431648),
    ///     _ => panic!("Incorrect timestamp_millis"),
    /// };
    /// ~~~~
    fn timestamp_millis_opt(&self, millis: i64) -> LocalResult<DateTime<Self>> {
        let (mut secs, mut millis) = (millis / 1000, millis % 1000);
        if millis < 0 {
            secs -= 1;
            millis += 1000;
        }
        self.timestamp_opt(secs, millis as u32 * 1_000_000)
    }

    /// Makes a new `DateTime` from the number of non-leap nanoseconds
    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp").
    ///
    /// Unlike [`timestamp_millis`](#method.timestamp_millis), this never
    /// panics.
    ///
    /// # Example
    ///
    /// ~~~~
    /// use chrono::{Utc, TimeZone};
    ///
    /// assert_eq!(Utc.timestamp_nanos(1431648000000000).timestamp(), 1431648);
    /// ~~~~
    fn timestamp_nanos(&self, nanos: i64) -> DateTime<Self> {
        let (mut secs, mut nanos) = (nanos / 1_000_000_000, nanos % 1_000_000_000);
        if nanos < 0 {
            secs -= 1;
            nanos += 1_000_000_000;
        }
        self.timestamp_opt(secs, nanos as u32).unwrap()
    }

    /// Parses a string with the specified format string and
    /// returns a `DateTime` with the current offset.
    /// See the [`format::strftime` module](../format/strftime/index.html)
    /// on the supported escape sequences.
    ///
    /// If the format does not include offsets, the current offset is assumed;
    /// otherwise the input should have a matching UTC offset.
    ///
    /// See also `DateTime::parse_from_str` which gives a local `DateTime`
    /// with parsed `FixedOffset`.
    fn datetime_from_str(&self, s: &str, fmt: &str) -> ParseResult<DateTime<Self>> {
        let mut parsed = Parsed::new();
        parse(&mut parsed, s, StrftimeItems::new(fmt))?;
        parsed.to_datetime_with_timezone(self)
    }

    /// Reconstructs the time zone from the offset.
    fn from_offset(offset: &Self::Offset) -> Self;

    /// Creates the offset(s) for given local `NaiveDate` if possible.
    fn offset_from_local_date(&self, local: &NaiveDate) -> LocalResult<Self::Offset>;

    /// Creates the offset(s) for given local `NaiveDateTime` if possible.
    fn offset_from_local_datetime(&self, local: &NaiveDateTime) -> LocalResult<Self::Offset>;

    /// Converts the local `NaiveDate` to the timezone-aware `Date` if possible.
    fn from_local_date(&self, local: &NaiveDate) -> LocalResult<Date<Self>> {
        self.offset_from_local_date(local).map(|offset| {
            // since FixedOffset is within +/- 1 day, the date is never affected
            Date::from_utc(*local, offset)
        })
    }

    /// Converts the local `NaiveDateTime` to the timezone-aware `DateTime` if possible.
    fn from_local_datetime(&self, local: &NaiveDateTime) -> LocalResult<DateTime<Self>> {
        self.offset_from_local_datetime(local)
            .map(|offset| DateTime::from_utc(*local - offset.fix(), offset))
    }

    /// Creates the offset for given UTC `NaiveDate`. This cannot fail.
    fn offset_from_utc_date(&self, utc: &NaiveDate) -> Self::Offset;

    /// Creates the offset for given UTC `NaiveDateTime`. This cannot fail.
    fn offset_from_utc_datetime(&self, utc: &NaiveDateTime) -> Self::Offset;

    /// Converts the UTC `NaiveDate` to the local time.
    /// The UTC is continuous and thus this cannot fail (but can give the duplicate local time).
    fn from_utc_date(&self, utc: &NaiveDate) -> Date<Self> {
        Date::from_utc(*utc, self.offset_from_utc_date(utc))
    }

    /// Converts the UTC `NaiveDateTime` to the local time.
    /// The UTC is continuous and thus this cannot fail (but can give the duplicate local time).
    fn from_utc_datetime(&self, utc: &NaiveDateTime) -> DateTime<Self> {
        DateTime::from_utc(*utc, self.offset_from_utc_datetime(utc))
    }
}

mod fixed;
#[cfg(feature = "clock")]
mod local;
mod utc;

pub use self::fixed::FixedOffset;
#[cfg(feature = "clock")]
pub use self::local::Local;
pub use self::utc::Utc;

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_negative_millis() {
        let dt = Utc.timestamp_millis(-1000);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:59 UTC");
        let dt = Utc.timestamp_millis(-7000);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:53 UTC");
        let dt = Utc.timestamp_millis(-7001);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:52.999 UTC");
        let dt = Utc.timestamp_millis(-7003);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:52.997 UTC");
        let dt = Utc.timestamp_millis(-999);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:59.001 UTC");
        let dt = Utc.timestamp_millis(-1);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:59.999 UTC");
        let dt = Utc.timestamp_millis(-60000);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:00 UTC");
        let dt = Utc.timestamp_millis(-3600000);
        assert_eq!(dt.to_string(), "1969-12-31 23:00:00 UTC");

        for (millis, expected) in &[
            (-7000, "1969-12-31 23:59:53 UTC"),
            (-7001, "1969-12-31 23:59:52.999 UTC"),
            (-7003, "1969-12-31 23:59:52.997 UTC"),
        ] {
            match Utc.timestamp_millis_opt(*millis) {
                LocalResult::Single(dt) => {
                    assert_eq!(dt.to_string(), *expected);
                },
                e => panic!("Got {:?} instead of an okay answer", e),
            }
        }

    }

    #[test]
    fn test_negative_nanos() {
        let dt = Utc.timestamp_nanos(-1_000_000_000);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:59 UTC");
        let dt = Utc.timestamp_nanos(-999_999_999);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:59.000000001 UTC");
        let dt = Utc.timestamp_nanos(-1);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:59.999999999 UTC");
        let dt = Utc.timestamp_nanos(-60_000_000_000);
        assert_eq!(dt.to_string(), "1969-12-31 23:59:00 UTC");
        let dt = Utc.timestamp_nanos(-3_600_000_000_000);
        assert_eq!(dt.to_string(), "1969-12-31 23:00:00 UTC");
    }

    #[test]
    fn test_nanos_never_panics() {
        Utc.timestamp_nanos(i64::max_value());
        Utc.timestamp_nanos(i64::default());
        Utc.timestamp_nanos(i64::min_value());
    }
}