time-tz 2.0.0

Implementation of tz database (IANA) for the time Rust crate.
Documentation 
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

// Copyright (c) 2022, Yuri6037
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of time-tz nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

use crate::{Offset, TimeZone, Tz};
use std::fmt::{Display, Formatter};
use thiserror::Error;
use time::{OffsetDateTime, UtcOffset};

mod r#abstract;
mod intermediate;
mod parser;

/// A range error returned when a field is out of the range defined in POSIX.
#[derive(Debug)]
pub enum RangeError {
    /// One of the time field in the given string was out of range.
    Time,

    /// One of the date field in the given string was out of range.
    Date,
}

impl Display for RangeError {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        match self {
            RangeError::Time => f.write_str("time field out of range"),
            RangeError::Date => f.write_str("date field out of range"),
        }
    }
}

/// The main type of error that is returned when a TZ POSIX string fails to parse.
#[derive(Debug, Error)]
pub enum ParseError<'a> {
    /// A nom parsing error.
    #[error("nom error: {:?}", .0)]
    Nom(nom::error::ErrorKind),

    /// In case a short format was given, the POSIX standard doesn't define what to do,
    /// in this implementation we just try to match the first tzdb timezone containing the
    /// short name; if none could be found this error variant is returned.
    #[error("unknown short timezone name `{0}`")]
    UnknownName(&'a str),

    /// We've exceeded the range of a field when checking for conformance against the POSIX
    /// standard.
    #[error("range error: {0}")]
    Range(RangeError),

    /// We've exceeded the range of a date component when converting types to time-rs.
    #[error("time component range error: {0}")]
    ComponentRange(time::error::ComponentRange),
}

/// The type of error return when a given Offset/PrimitiveDateTime cannot be represented
/// in a given POSIX TZ formatted "timezone".
#[derive(Debug, Error)]
pub enum Error {
    /// We've exceeded the range of a date component when converting types to time-rs.
    #[error("time component range error: {0}")]
    ComponentRange(time::error::ComponentRange),

    /// We've exceeded the maximum date supported by time-rs.
    #[error("value of Date too large")]
    DateTooLarge,
}

/// A POSIX "timezone" offset.
pub struct PosixTzOffset<'a> {
    inner: r#abstract::TzOrExpandedOffset<'a>,
}

impl<'a> Offset for PosixTzOffset<'a> {
    fn to_utc(&self) -> UtcOffset {
        match &self.inner {
            r#abstract::TzOrExpandedOffset::Expanded(v) => v.to_utc(),
            r#abstract::TzOrExpandedOffset::Tz(v) => v.to_utc(),
        }
    }

    fn name(&self) -> &str {
        match &self.inner {
            r#abstract::TzOrExpandedOffset::Expanded(v) => v.name(),
            r#abstract::TzOrExpandedOffset::Tz(v) => v.name(),
        }
    }

    fn is_dst(&self) -> bool {
        match &self.inner {
            r#abstract::TzOrExpandedOffset::Expanded(v) => v.is_dst(),
            r#abstract::TzOrExpandedOffset::Tz(v) => v.is_dst(),
        }
    }
}

/// A "timezone" in POSIX TZ format.
pub struct PosixTz<'a> {
    inner: r#abstract::TzOrExpanded<'a>,
}

impl<'a> PosixTz<'a> {
    /// Parse the given POSIX TZ string.
    ///
    /// # Arguments
    ///
    /// * `input`: the string to parse.
    ///
    /// returns: Result<PosixTz, ParseError>
    ///
    /// # Errors
    ///
    /// Returns a [ParseError](crate::posix_tz::ParseError) if the given string is not a valid
    /// POSIX "timezone".
    pub fn parse(input: &'a str) -> Result<PosixTz<'a>, ParseError> {
        let intermediate = intermediate::parse_intermediate(input)?;
        let inner = r#abstract::parse_abstract(intermediate)?;
        Ok(PosixTz { inner })
    }

    /// Convert the given date_time to this "timezone".
    ///
    /// # Arguments
    ///
    /// * `date_time`: the date time to convert.
    ///
    /// returns: Result<OffsetDateTime, Error>
    ///
    /// # Errors
    ///
    /// Returns an [Error](crate::posix_tz::Error) if the date_time cannot be represented in this
    /// "timezone".
    pub fn convert(&self, date_time: &OffsetDateTime) -> Result<OffsetDateTime, Error> {
        let offset = self.get_offset(date_time)?;
        Ok(date_time.to_offset(offset.to_utc()))
    }

    /// Calculates the offset to add to the given date_time to convert it to this "timezone".
    ///
    /// # Arguments
    ///
    /// * `date_time`: the date time to calculate offset of.
    ///
    /// returns: Result<OffsetDateTime, Error>
    ///
    /// # Errors
    ///
    /// Returns an [Error](crate::posix_tz::Error) if the date_time cannot be represented in this
    /// "timezone".
    pub fn get_offset(&self, date_time: &OffsetDateTime) -> Result<PosixTzOffset<'a>, Error> {
        Ok(match &self.inner {
            r#abstract::TzOrExpanded::Tz(v) => PosixTzOffset {
                inner: r#abstract::TzOrExpandedOffset::Tz(v.get_offset_utc(date_time)),
            },
            r#abstract::TzOrExpanded::Expanded(v) => PosixTzOffset {
                inner: r#abstract::TzOrExpandedOffset::Expanded(v.get_offset_utc(date_time)?),
            },
        })
    }

    /// Gets the current time in this "timezone".
    ///
    /// returns: Result<OffsetDateTime, Error>
    ///
    /// # Errors
    ///
    /// Returns an [Error](crate::posix_tz::Error) if the current time cannot be represented in
    /// this "timezone".
    pub fn now(&self) -> Result<OffsetDateTime, Error> {
        self.convert(&OffsetDateTime::now_utc())
    }

    /// Returns the precise IANA TimeZone associated to this POSIX "timezone".
    ///
    /// If this POSIX "timezone" is not a precise IANA TimeZone, None is returned.
    pub fn as_iana(&self) -> Option<&'static Tz> {
        match &self.inner {
            r#abstract::TzOrExpanded::Tz(v) => Some(*v),
            r#abstract::TzOrExpanded::Expanded(_) => None,
        }
    }
}