arrow_array/
timezone.rs

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
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

//! Timezone for timestamp arrays

use arrow_schema::ArrowError;
use chrono::FixedOffset;
pub use private::{Tz, TzOffset};

/// Parses a fixed offset of the form "+09:00", "-09" or "+0930"
fn parse_fixed_offset(tz: &str) -> Option<FixedOffset> {
    let bytes = tz.as_bytes();

    let mut values = match bytes.len() {
        // [+-]XX:XX
        6 if bytes[3] == b':' => [bytes[1], bytes[2], bytes[4], bytes[5]],
        // [+-]XXXX
        5 => [bytes[1], bytes[2], bytes[3], bytes[4]],
        // [+-]XX
        3 => [bytes[1], bytes[2], b'0', b'0'],
        _ => return None,
    };
    values.iter_mut().for_each(|x| *x = x.wrapping_sub(b'0'));
    if values.iter().any(|x| *x > 9) {
        return None;
    }
    let secs =
        (values[0] * 10 + values[1]) as i32 * 60 * 60 + (values[2] * 10 + values[3]) as i32 * 60;

    match bytes[0] {
        b'+' => FixedOffset::east_opt(secs),
        b'-' => FixedOffset::west_opt(secs),
        _ => None,
    }
}

#[cfg(feature = "chrono-tz")]
mod private {
    use super::*;
    use chrono::offset::TimeZone;
    use chrono::{LocalResult, NaiveDate, NaiveDateTime, Offset};
    use std::str::FromStr;

    /// An [`Offset`] for [`Tz`]
    #[derive(Debug, Copy, Clone)]
    pub struct TzOffset {
        tz: Tz,
        offset: FixedOffset,
    }

    impl std::fmt::Display for TzOffset {
        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
            self.offset.fmt(f)
        }
    }

    impl Offset for TzOffset {
        fn fix(&self) -> FixedOffset {
            self.offset
        }
    }

    /// An Arrow [`TimeZone`]
    #[derive(Debug, Copy, Clone)]
    pub struct Tz(TzInner);

    #[derive(Debug, Copy, Clone)]
    enum TzInner {
        Timezone(chrono_tz::Tz),
        Offset(FixedOffset),
    }

    impl FromStr for Tz {
        type Err = ArrowError;

        fn from_str(tz: &str) -> Result<Self, Self::Err> {
            match parse_fixed_offset(tz) {
                Some(offset) => Ok(Self(TzInner::Offset(offset))),
                None => Ok(Self(TzInner::Timezone(tz.parse().map_err(|e| {
                    ArrowError::ParseError(format!("Invalid timezone \"{tz}\": {e}"))
                })?))),
            }
        }
    }

    macro_rules! tz {
        ($s:ident, $tz:ident, $b:block) => {
            match $s.0 {
                TzInner::Timezone($tz) => $b,
                TzInner::Offset($tz) => $b,
            }
        };
    }

    impl TimeZone for Tz {
        type Offset = TzOffset;

        fn from_offset(offset: &Self::Offset) -> Self {
            offset.tz
        }

        fn offset_from_local_date(&self, local: &NaiveDate) -> LocalResult<Self::Offset> {
            tz!(self, tz, {
                tz.offset_from_local_date(local).map(|x| TzOffset {
                    tz: *self,
                    offset: x.fix(),
                })
            })
        }

        fn offset_from_local_datetime(&self, local: &NaiveDateTime) -> LocalResult<Self::Offset> {
            tz!(self, tz, {
                tz.offset_from_local_datetime(local).map(|x| TzOffset {
                    tz: *self,
                    offset: x.fix(),
                })
            })
        }

        fn offset_from_utc_date(&self, utc: &NaiveDate) -> Self::Offset {
            tz!(self, tz, {
                TzOffset {
                    tz: *self,
                    offset: tz.offset_from_utc_date(utc).fix(),
                }
            })
        }

        fn offset_from_utc_datetime(&self, utc: &NaiveDateTime) -> Self::Offset {
            tz!(self, tz, {
                TzOffset {
                    tz: *self,
                    offset: tz.offset_from_utc_datetime(utc).fix(),
                }
            })
        }
    }

    #[cfg(test)]
    mod tests {
        use super::*;
        use chrono::{Timelike, Utc};

        #[test]
        fn test_with_timezone() {
            let vals = [
                Utc.timestamp_millis_opt(37800000).unwrap(),
                Utc.timestamp_millis_opt(86339000).unwrap(),
            ];

            assert_eq!(10, vals[0].hour());
            assert_eq!(23, vals[1].hour());

            let tz: Tz = "America/Los_Angeles".parse().unwrap();

            assert_eq!(2, vals[0].with_timezone(&tz).hour());
            assert_eq!(15, vals[1].with_timezone(&tz).hour());
        }

        #[test]
        fn test_using_chrono_tz_and_utc_naive_date_time() {
            let sydney_tz = "Australia/Sydney".to_string();
            let tz: Tz = sydney_tz.parse().unwrap();
            let sydney_offset_without_dst = FixedOffset::east_opt(10 * 60 * 60).unwrap();
            let sydney_offset_with_dst = FixedOffset::east_opt(11 * 60 * 60).unwrap();
            // Daylight savings ends
            // When local daylight time was about to reach
            // Sunday, 4 April 2021, 3:00:00 am clocks were turned backward 1 hour to
            // Sunday, 4 April 2021, 2:00:00 am local standard time instead.

            // Daylight savings starts
            // When local standard time was about to reach
            // Sunday, 3 October 2021, 2:00:00 am clocks were turned forward 1 hour to
            // Sunday, 3 October 2021, 3:00:00 am local daylight time instead.

            // Sydney 2021-04-04T02:30:00+11:00 is 2021-04-03T15:30:00Z
            let utc_just_before_sydney_dst_ends = NaiveDate::from_ymd_opt(2021, 4, 3)
                .unwrap()
                .and_hms_nano_opt(15, 30, 0, 0)
                .unwrap();
            assert_eq!(
                tz.offset_from_utc_datetime(&utc_just_before_sydney_dst_ends)
                    .fix(),
                sydney_offset_with_dst
            );
            // Sydney 2021-04-04T02:30:00+10:00 is 2021-04-03T16:30:00Z
            let utc_just_after_sydney_dst_ends = NaiveDate::from_ymd_opt(2021, 4, 3)
                .unwrap()
                .and_hms_nano_opt(16, 30, 0, 0)
                .unwrap();
            assert_eq!(
                tz.offset_from_utc_datetime(&utc_just_after_sydney_dst_ends)
                    .fix(),
                sydney_offset_without_dst
            );
            // Sydney 2021-10-03T01:30:00+10:00 is 2021-10-02T15:30:00Z
            let utc_just_before_sydney_dst_starts = NaiveDate::from_ymd_opt(2021, 10, 2)
                .unwrap()
                .and_hms_nano_opt(15, 30, 0, 0)
                .unwrap();
            assert_eq!(
                tz.offset_from_utc_datetime(&utc_just_before_sydney_dst_starts)
                    .fix(),
                sydney_offset_without_dst
            );
            // Sydney 2021-04-04T03:30:00+11:00 is 2021-10-02T16:30:00Z
            let utc_just_after_sydney_dst_starts = NaiveDate::from_ymd_opt(2022, 10, 2)
                .unwrap()
                .and_hms_nano_opt(16, 30, 0, 0)
                .unwrap();
            assert_eq!(
                tz.offset_from_utc_datetime(&utc_just_after_sydney_dst_starts)
                    .fix(),
                sydney_offset_with_dst
            );
        }
    }
}

#[cfg(not(feature = "chrono-tz"))]
mod private {
    use super::*;
    use chrono::offset::TimeZone;
    use chrono::{LocalResult, NaiveDate, NaiveDateTime, Offset};
    use std::str::FromStr;

    /// An [`Offset`] for [`Tz`]
    #[derive(Debug, Copy, Clone)]
    pub struct TzOffset(FixedOffset);

    impl std::fmt::Display for TzOffset {
        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
            self.0.fmt(f)
        }
    }

    impl Offset for TzOffset {
        fn fix(&self) -> FixedOffset {
            self.0
        }
    }

    /// An Arrow [`TimeZone`]
    #[derive(Debug, Copy, Clone)]
    pub struct Tz(FixedOffset);

    impl FromStr for Tz {
        type Err = ArrowError;

        fn from_str(tz: &str) -> Result<Self, Self::Err> {
            let offset = parse_fixed_offset(tz).ok_or_else(|| {
                ArrowError::ParseError(format!(
                    "Invalid timezone \"{tz}\": only offset based timezones supported without chrono-tz feature"
                ))
            })?;
            Ok(Self(offset))
        }
    }

    impl TimeZone for Tz {
        type Offset = TzOffset;

        fn from_offset(offset: &Self::Offset) -> Self {
            Self(offset.0)
        }

        fn offset_from_local_date(&self, local: &NaiveDate) -> LocalResult<Self::Offset> {
            self.0.offset_from_local_date(local).map(TzOffset)
        }

        fn offset_from_local_datetime(&self, local: &NaiveDateTime) -> LocalResult<Self::Offset> {
            self.0.offset_from_local_datetime(local).map(TzOffset)
        }

        fn offset_from_utc_date(&self, utc: &NaiveDate) -> Self::Offset {
            TzOffset(self.0.offset_from_utc_date(utc).fix())
        }

        fn offset_from_utc_datetime(&self, utc: &NaiveDateTime) -> Self::Offset {
            TzOffset(self.0.offset_from_utc_datetime(utc).fix())
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use chrono::{NaiveDate, Offset, TimeZone};

    #[test]
    fn test_with_offset() {
        let t = NaiveDate::from_ymd_opt(2000, 1, 1).unwrap();

        let tz: Tz = "-00:00".parse().unwrap();
        assert_eq!(tz.offset_from_utc_date(&t).fix().local_minus_utc(), 0);
        let tz: Tz = "+00:00".parse().unwrap();
        assert_eq!(tz.offset_from_utc_date(&t).fix().local_minus_utc(), 0);

        let tz: Tz = "-10:00".parse().unwrap();
        assert_eq!(
            tz.offset_from_utc_date(&t).fix().local_minus_utc(),
            -10 * 60 * 60
        );
        let tz: Tz = "+09:00".parse().unwrap();
        assert_eq!(
            tz.offset_from_utc_date(&t).fix().local_minus_utc(),
            9 * 60 * 60
        );

        let tz = "+09".parse::<Tz>().unwrap();
        assert_eq!(
            tz.offset_from_utc_date(&t).fix().local_minus_utc(),
            9 * 60 * 60
        );

        let tz = "+0900".parse::<Tz>().unwrap();
        assert_eq!(
            tz.offset_from_utc_date(&t).fix().local_minus_utc(),
            9 * 60 * 60
        );

        let err = "+9:00".parse::<Tz>().unwrap_err().to_string();
        assert!(err.contains("Invalid timezone"), "{}", err);
    }
}