aboutsummaryrefslogtreecommitdiffstats
path: root/activesupport/lib/active_support/values/time_zone.rb
blob: 4d81ac939effaf1c25d607136886c13227a44ee9 (plain) (blame)
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
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
# frozen_string_literal: true

require "tzinfo"
require "concurrent/map"
require "active_support/core_ext/object/blank"

module ActiveSupport
  # The TimeZone class serves as a wrapper around TZInfo::Timezone instances.
  # It allows us to do the following:
  #
  # * Limit the set of zones provided by TZInfo to a meaningful subset of 134
  #   zones.
  # * Retrieve and display zones with a friendlier name
  #   (e.g., "Eastern Time (US & Canada)" instead of "America/New_York").
  # * Lazily load TZInfo::Timezone instances only when they're needed.
  # * Create ActiveSupport::TimeWithZone instances via TimeZone's +local+,
  #   +parse+, +at+ and +now+ methods.
  #
  # If you set <tt>config.time_zone</tt> in the Rails Application, you can
  # access this TimeZone object via <tt>Time.zone</tt>:
  #
  #   # application.rb:
  #   class Application < Rails::Application
  #     config.time_zone = 'Eastern Time (US & Canada)'
  #   end
  #
  #   Time.zone      # => #<ActiveSupport::TimeZone:0x514834...>
  #   Time.zone.name # => "Eastern Time (US & Canada)"
  #   Time.zone.now  # => Sun, 18 May 2008 14:30:44 EDT -04:00
  class TimeZone
    # Keys are Rails TimeZone names, values are TZInfo identifiers.
    MAPPING = {
      "International Date Line West" => "Etc/GMT+12",
      "Midway Island"                => "Pacific/Midway",
      "American Samoa"               => "Pacific/Pago_Pago",
      "Hawaii"                       => "Pacific/Honolulu",
      "Alaska"                       => "America/Juneau",
      "Pacific Time (US & Canada)"   => "America/Los_Angeles",
      "Tijuana"                      => "America/Tijuana",
      "Mountain Time (US & Canada)"  => "America/Denver",
      "Arizona"                      => "America/Phoenix",
      "Chihuahua"                    => "America/Chihuahua",
      "Mazatlan"                     => "America/Mazatlan",
      "Central Time (US & Canada)"   => "America/Chicago",
      "Saskatchewan"                 => "America/Regina",
      "Guadalajara"                  => "America/Mexico_City",
      "Mexico City"                  => "America/Mexico_City",
      "Monterrey"                    => "America/Monterrey",
      "Central America"              => "America/Guatemala",
      "Eastern Time (US & Canada)"   => "America/New_York",
      "Indiana (East)"               => "America/Indiana/Indianapolis",
      "Bogota"                       => "America/Bogota",
      "Lima"                         => "America/Lima",
      "Quito"                        => "America/Lima",
      "Atlantic Time (Canada)"       => "America/Halifax",
      "Caracas"                      => "America/Caracas",
      "La Paz"                       => "America/La_Paz",
      "Santiago"                     => "America/Santiago",
      "Newfoundland"                 => "America/St_Johns",
      "Brasilia"                     => "America/Sao_Paulo",
      "Buenos Aires"                 => "America/Argentina/Buenos_Aires",
      "Montevideo"                   => "America/Montevideo",
      "Georgetown"                   => "America/Guyana",
      "Puerto Rico"                  => "America/Puerto_Rico",
      "Greenland"                    => "America/Godthab",
      "Mid-Atlantic"                 => "Atlantic/South_Georgia",
      "Azores"                       => "Atlantic/Azores",
      "Cape Verde Is."               => "Atlantic/Cape_Verde",
      "Dublin"                       => "Europe/Dublin",
      "Edinburgh"                    => "Europe/London",
      "Lisbon"                       => "Europe/Lisbon",
      "London"                       => "Europe/London",
      "Casablanca"                   => "Africa/Casablanca",
      "Monrovia"                     => "Africa/Monrovia",
      "UTC"                          => "Etc/UTC",
      "Belgrade"                     => "Europe/Belgrade",
      "Bratislava"                   => "Europe/Bratislava",
      "Budapest"                     => "Europe/Budapest",
      "Ljubljana"                    => "Europe/Ljubljana",
      "Prague"                       => "Europe/Prague",
      "Sarajevo"                     => "Europe/Sarajevo",
      "Skopje"                       => "Europe/Skopje",
      "Warsaw"                       => "Europe/Warsaw",
      "Zagreb"                       => "Europe/Zagreb",
      "Brussels"                     => "Europe/Brussels",
      "Copenhagen"                   => "Europe/Copenhagen",
      "Madrid"                       => "Europe/Madrid",
      "Paris"                        => "Europe/Paris",
      "Amsterdam"                    => "Europe/Amsterdam",
      "Berlin"                       => "Europe/Berlin",
      "Bern"                         => "Europe/Zurich",
      "Zurich"                       => "Europe/Zurich",
      "Rome"                         => "Europe/Rome",
      "Stockholm"                    => "Europe/Stockholm",
      "Vienna"                       => "Europe/Vienna",
      "West Central Africa"          => "Africa/Algiers",
      "Bucharest"                    => "Europe/Bucharest",
      "Cairo"                        => "Africa/Cairo",
      "Helsinki"                     => "Europe/Helsinki",
      "Kyiv"                         => "Europe/Kiev",
      "Riga"                         => "Europe/Riga",
      "Sofia"                        => "Europe/Sofia",
      "Tallinn"                      => "Europe/Tallinn",
      "Vilnius"                      => "Europe/Vilnius",
      "Athens"                       => "Europe/Athens",
      "Istanbul"                     => "Europe/Istanbul",
      "Minsk"                        => "Europe/Minsk",
      "Jerusalem"                    => "Asia/Jerusalem",
      "Harare"                       => "Africa/Harare",
      "Pretoria"                     => "Africa/Johannesburg",
      "Kaliningrad"                  => "Europe/Kaliningrad",
      "Moscow"                       => "Europe/Moscow",
      "St. Petersburg"               => "Europe/Moscow",
      "Volgograd"                    => "Europe/Volgograd",
      "Samara"                       => "Europe/Samara",
      "Kuwait"                       => "Asia/Kuwait",
      "Riyadh"                       => "Asia/Riyadh",
      "Nairobi"                      => "Africa/Nairobi",
      "Baghdad"                      => "Asia/Baghdad",
      "Tehran"                       => "Asia/Tehran",
      "Abu Dhabi"                    => "Asia/Muscat",
      "Muscat"                       => "Asia/Muscat",
      "Baku"                         => "Asia/Baku",
      "Tbilisi"                      => "Asia/Tbilisi",
      "Yerevan"                      => "Asia/Yerevan",
      "Kabul"                        => "Asia/Kabul",
      "Ekaterinburg"                 => "Asia/Yekaterinburg",
      "Islamabad"                    => "Asia/Karachi",
      "Karachi"                      => "Asia/Karachi",
      "Tashkent"                     => "Asia/Tashkent",
      "Chennai"                      => "Asia/Kolkata",
      "Kolkata"                      => "Asia/Kolkata",
      "Mumbai"                       => "Asia/Kolkata",
      "New Delhi"                    => "Asia/Kolkata",
      "Kathmandu"                    => "Asia/Kathmandu",
      "Astana"                       => "Asia/Dhaka",
      "Dhaka"                        => "Asia/Dhaka",
      "Sri Jayawardenepura"          => "Asia/Colombo",
      "Almaty"                       => "Asia/Almaty",
      "Novosibirsk"                  => "Asia/Novosibirsk",
      "Rangoon"                      => "Asia/Rangoon",
      "Bangkok"                      => "Asia/Bangkok",
      "Hanoi"                        => "Asia/Bangkok",
      "Jakarta"                      => "Asia/Jakarta",
      "Krasnoyarsk"                  => "Asia/Krasnoyarsk",
      "Beijing"                      => "Asia/Shanghai",
      "Chongqing"                    => "Asia/Chongqing",
      "Hong Kong"                    => "Asia/Hong_Kong",
      "Urumqi"                       => "Asia/Urumqi",
      "Kuala Lumpur"                 => "Asia/Kuala_Lumpur",
      "Singapore"                    => "Asia/Singapore",
      "Taipei"                       => "Asia/Taipei",
      "Perth"                        => "Australia/Perth",
      "Irkutsk"                      => "Asia/Irkutsk",
      "Ulaanbaatar"                  => "Asia/Ulaanbaatar",
      "Seoul"                        => "Asia/Seoul",
      "Osaka"                        => "Asia/Tokyo",
      "Sapporo"                      => "Asia/Tokyo",
      "Tokyo"                        => "Asia/Tokyo",
      "Yakutsk"                      => "Asia/Yakutsk",
      "Darwin"                       => "Australia/Darwin",
      "Adelaide"                     => "Australia/Adelaide",
      "Canberra"                     => "Australia/Melbourne",
      "Melbourne"                    => "Australia/Melbourne",
      "Sydney"                       => "Australia/Sydney",
      "Brisbane"                     => "Australia/Brisbane",
      "Hobart"                       => "Australia/Hobart",
      "Vladivostok"                  => "Asia/Vladivostok",
      "Guam"                         => "Pacific/Guam",
      "Port Moresby"                 => "Pacific/Port_Moresby",
      "Magadan"                      => "Asia/Magadan",
      "Srednekolymsk"                => "Asia/Srednekolymsk",
      "Solomon Is."                  => "Pacific/Guadalcanal",
      "New Caledonia"                => "Pacific/Noumea",
      "Fiji"                         => "Pacific/Fiji",
      "Kamchatka"                    => "Asia/Kamchatka",
      "Marshall Is."                 => "Pacific/Majuro",
      "Auckland"                     => "Pacific/Auckland",
      "Wellington"                   => "Pacific/Auckland",
      "Nuku'alofa"                   => "Pacific/Tongatapu",
      "Tokelau Is."                  => "Pacific/Fakaofo",
      "Chatham Is."                  => "Pacific/Chatham",
      "Samoa"                        => "Pacific/Apia"
    }

    UTC_OFFSET_WITH_COLON = "%s%02d:%02d"
    UTC_OFFSET_WITHOUT_COLON = UTC_OFFSET_WITH_COLON.tr(":", "")

    @lazy_zones_map = Concurrent::Map.new
    @country_zones  = Concurrent::Map.new

    class << self
      # Assumes self represents an offset from UTC in seconds (as returned from
      # Time#utc_offset) and turns this into an +HH:MM formatted string.
      #
      #   ActiveSupport::TimeZone.seconds_to_utc_offset(-21_600) # => "-06:00"
      def seconds_to_utc_offset(seconds, colon = true)
        format = colon ? UTC_OFFSET_WITH_COLON : UTC_OFFSET_WITHOUT_COLON
        sign = (seconds < 0 ? "-" : "+")
        hours = seconds.abs / 3600
        minutes = (seconds.abs % 3600) / 60
        format % [sign, hours, minutes]
      end

      def find_tzinfo(name)
        TZInfo::Timezone.new(MAPPING[name] || name)
      end

      alias_method :create, :new

      # Returns a TimeZone instance with the given name, or +nil+ if no
      # such TimeZone instance exists. (This exists to support the use of
      # this class with the +composed_of+ macro.)
      def new(name)
        self[name]
      end

      # Returns an array of all TimeZone objects. There are multiple
      # TimeZone objects per time zone, in many cases, to make it easier
      # for users to find their own time zone.
      def all
        @zones ||= zones_map.values.sort
      end

      # Locate a specific time zone object. If the argument is a string, it
      # is interpreted to mean the name of the timezone to locate. If it is a
      # numeric value it is either the hour offset, or the second offset, of the
      # timezone to find. (The first one with that offset will be returned.)
      # Returns +nil+ if no such time zone is known to the system.
      def [](arg)
        case arg
        when String
          begin
            @lazy_zones_map[arg] ||= create(arg)
          rescue TZInfo::InvalidTimezoneIdentifier
            nil
          end
        when Numeric, ActiveSupport::Duration
          arg *= 3600 if arg.abs <= 13
          all.find { |z| z.utc_offset == arg.to_i }
          else
          raise ArgumentError, "invalid argument to TimeZone[]: #{arg.inspect}"
        end
      end

      # A convenience method for returning a collection of TimeZone objects
      # for time zones in the USA.
      def us_zones
        country_zones(:us)
      end

      # A convenience method for returning a collection of TimeZone objects
      # for time zones in the country specified by its ISO 3166-1 Alpha2 code.
      def country_zones(country_code)
        code = country_code.to_s.upcase
        @country_zones[code] ||= load_country_zones(code)
      end

      def clear #:nodoc:
        @lazy_zones_map = Concurrent::Map.new
        @country_zones  = Concurrent::Map.new
        @zones = nil
        @zones_map = nil
      end

      private
        def load_country_zones(code)
          country = TZInfo::Country.get(code)
          country.zone_identifiers.map do |tz_id|
            if MAPPING.value?(tz_id)
              self[MAPPING.key(tz_id)]
            else
              create(tz_id, nil, TZInfo::Timezone.new(tz_id))
            end
          end.sort!
        end

        def zones_map
          @zones_map ||= MAPPING.each_with_object({}) do |(name, _), zones|
            zones[name] = self[name]
          end
        end
    end

    include Comparable
    attr_reader :name
    attr_reader :tzinfo

    # Create a new TimeZone object with the given name and offset. The
    # offset is the number of seconds that this time zone is offset from UTC
    # (GMT). Seconds were chosen as the offset unit because that is the unit
    # that Ruby uses to represent time zone offsets (see Time#utc_offset).
    def initialize(name, utc_offset = nil, tzinfo = nil)
      @name = name
      @utc_offset = utc_offset
      @tzinfo = tzinfo || TimeZone.find_tzinfo(name)
    end

    # Returns the offset of this time zone from UTC in seconds.
    def utc_offset
      if @utc_offset
        @utc_offset
      else
        tzinfo.current_period.utc_offset if tzinfo && tzinfo.current_period
      end
    end

    # Returns a formatted string of the offset from UTC, or an alternative
    # string if the time zone is already UTC.
    #
    #   zone = ActiveSupport::TimeZone['Central Time (US & Canada)']
    #   zone.formatted_offset        # => "-06:00"
    #   zone.formatted_offset(false) # => "-0600"
    def formatted_offset(colon = true, alternate_utc_string = nil)
      utc_offset == 0 && alternate_utc_string || self.class.seconds_to_utc_offset(utc_offset, colon)
    end

    # Compare this time zone to the parameter. The two are compared first on
    # their offsets, and then by name.
    def <=>(zone)
      return unless zone.respond_to? :utc_offset
      result = (utc_offset <=> zone.utc_offset)
      result = (name <=> zone.name) if result == 0
      result
    end

    # Compare #name and TZInfo identifier to a supplied regexp, returning +true+
    # if a match is found.
    def =~(re)
      re === name || re === MAPPING[name]
    end

    # Returns a textual representation of this time zone.
    def to_s
      "(GMT#{formatted_offset}) #{name}"
    end

    # Method for creating new ActiveSupport::TimeWithZone instance in time zone
    # of +self+ from given values.
    #
    #   Time.zone = 'Hawaii'                    # => "Hawaii"
    #   Time.zone.local(2007, 2, 1, 15, 30, 45) # => Thu, 01 Feb 2007 15:30:45 HST -10:00
    def local(*args)
      time = Time.utc(*args)
      ActiveSupport::TimeWithZone.new(nil, self, time)
    end

    # Method for creating new ActiveSupport::TimeWithZone instance in time zone
    # of +self+ from number of seconds since the Unix epoch.
    #
    #   Time.zone = 'Hawaii'        # => "Hawaii"
    #   Time.utc(2000).to_f         # => 946684800.0
    #   Time.zone.at(946684800.0)   # => Fri, 31 Dec 1999 14:00:00 HST -10:00
    def at(secs)
      Time.at(secs).utc.in_time_zone(self)
    end

    # Method for creating new ActiveSupport::TimeWithZone instance in time zone
    # of +self+ from an ISO 8601 string.
    #
    #   Time.zone = 'Hawaii'                     # => "Hawaii"
    #   Time.zone.iso8601('1999-12-31T14:00:00') # => Fri, 31 Dec 1999 14:00:00 HST -10:00
    #
    # If the time components are missing then they will be set to zero.
    #
    #   Time.zone = 'Hawaii'            # => "Hawaii"
    #   Time.zone.iso8601('1999-12-31') # => Fri, 31 Dec 1999 00:00:00 HST -10:00
    #
    # If the string is invalid then an +ArgumentError+ will be raised unlike +parse+
    # which usually returns +nil+ when given an invalid date string.
    def iso8601(str)
      parts = Date._iso8601(str)

      raise ArgumentError, "invalid date" if parts.empty?

      time = Time.new(
        parts.fetch(:year),
        parts.fetch(:mon),
        parts.fetch(:mday),
        parts.fetch(:hour, 0),
        parts.fetch(:min, 0),
        parts.fetch(:sec, 0) + parts.fetch(:sec_fraction, 0),
        parts.fetch(:offset, 0)
      )

      if parts[:offset]
        TimeWithZone.new(time.utc, self)
      else
        TimeWithZone.new(nil, self, time)
      end
    end

    # Method for creating new ActiveSupport::TimeWithZone instance in time zone
    # of +self+ from parsed string.
    #
    #   Time.zone = 'Hawaii'                   # => "Hawaii"
    #   Time.zone.parse('1999-12-31 14:00:00') # => Fri, 31 Dec 1999 14:00:00 HST -10:00
    #
    # If upper components are missing from the string, they are supplied from
    # TimeZone#now:
    #
    #   Time.zone.now               # => Fri, 31 Dec 1999 14:00:00 HST -10:00
    #   Time.zone.parse('22:30:00') # => Fri, 31 Dec 1999 22:30:00 HST -10:00
    #
    # However, if the date component is not provided, but any other upper
    # components are supplied, then the day of the month defaults to 1:
    #
    #   Time.zone.parse('Mar 2000') # => Wed, 01 Mar 2000 00:00:00 HST -10:00
    #
    # If the string is invalid then an +ArgumentError+ could be raised.
    def parse(str, now = now())
      parts_to_time(Date._parse(str, false), now)
    end

    # Method for creating new ActiveSupport::TimeWithZone instance in time zone
    # of +self+ from an RFC 3339 string.
    #
    #   Time.zone = 'Hawaii'                     # => "Hawaii"
    #   Time.zone.rfc3339('2000-01-01T00:00:00Z') # => Fri, 31 Dec 1999 14:00:00 HST -10:00
    #
    # If the time or zone components are missing then an +ArgumentError+ will
    # be raised. This is much stricter than either +parse+ or +iso8601+ which
    # allow for missing components.
    #
    #   Time.zone = 'Hawaii'            # => "Hawaii"
    #   Time.zone.rfc3339('1999-12-31') # => ArgumentError: invalid date
    def rfc3339(str)
      parts = Date._rfc3339(str)

      raise ArgumentError, "invalid date" if parts.empty?

      time = Time.new(
        parts.fetch(:year),
        parts.fetch(:mon),
        parts.fetch(:mday),
        parts.fetch(:hour),
        parts.fetch(:min),
        parts.fetch(:sec) + parts.fetch(:sec_fraction, 0),
        parts.fetch(:offset)
      )

      TimeWithZone.new(time.utc, self)
    end

    # Parses +str+ according to +format+ and returns an ActiveSupport::TimeWithZone.
    #
    # Assumes that +str+ is a time in the time zone +self+,
    # unless +format+ includes an explicit time zone.
    # (This is the same behavior as +parse+.)
    # In either case, the returned TimeWithZone has the timezone of +self+.
    #
    #   Time.zone = 'Hawaii'                   # => "Hawaii"
    #   Time.zone.strptime('1999-12-31 14:00:00', '%Y-%m-%d %H:%M:%S') # => Fri, 31 Dec 1999 14:00:00 HST -10:00
    #
    # If upper components are missing from the string, they are supplied from
    # TimeZone#now:
    #
    #   Time.zone.now                              # => Fri, 31 Dec 1999 14:00:00 HST -10:00
    #   Time.zone.strptime('22:30:00', '%H:%M:%S') # => Fri, 31 Dec 1999 22:30:00 HST -10:00
    #
    # However, if the date component is not provided, but any other upper
    # components are supplied, then the day of the month defaults to 1:
    #
    #   Time.zone.strptime('Mar 2000', '%b %Y') # => Wed, 01 Mar 2000 00:00:00 HST -10:00
    def strptime(str, format, now = now())
      parts_to_time(DateTime._strptime(str, format), now)
    end

    # Returns an ActiveSupport::TimeWithZone instance representing the current
    # time in the time zone represented by +self+.
    #
    #   Time.zone = 'Hawaii'  # => "Hawaii"
    #   Time.zone.now         # => Wed, 23 Jan 2008 20:24:27 HST -10:00
    def now
      time_now.utc.in_time_zone(self)
    end

    # Returns the current date in this time zone.
    def today
      tzinfo.now.to_date
    end

    # Returns the next date in this time zone.
    def tomorrow
      today + 1
    end

    # Returns the previous date in this time zone.
    def yesterday
      today - 1
    end

    # Adjust the given time to the simultaneous time in the time zone
    # represented by +self+. Returns a Time.utc() instance -- if you want an
    # ActiveSupport::TimeWithZone instance, use Time#in_time_zone() instead.
    def utc_to_local(time)
      tzinfo.utc_to_local(time)
    end

    # Adjust the given time to the simultaneous time in UTC. Returns a
    # Time.utc() instance.
    def local_to_utc(time, dst = true)
      tzinfo.local_to_utc(time, dst)
    end

    # Available so that TimeZone instances respond like TZInfo::Timezone
    # instances.
    def period_for_utc(time)
      tzinfo.period_for_utc(time)
    end

    # Available so that TimeZone instances respond like TZInfo::Timezone
    # instances.
    def period_for_local(time, dst = true)
      tzinfo.period_for_local(time, dst) { |periods| periods.last }
    end

    def periods_for_local(time) #:nodoc:
      tzinfo.periods_for_local(time)
    end

    def init_with(coder) #:nodoc:
      initialize(coder["name"])
    end

    def encode_with(coder) #:nodoc:
      coder.tag = "!ruby/object:#{self.class}"
      coder.map = { "name" => tzinfo.name }
    end

    private
      def parts_to_time(parts, now)
        raise ArgumentError, "invalid date" if parts.nil?
        return if parts.empty?

        if parts[:seconds]
          time = Time.at(parts[:seconds])
        else
          time = Time.new(
            parts.fetch(:year, now.year),
            parts.fetch(:mon, now.month),
            parts.fetch(:mday, parts[:year] || parts[:mon] ? 1 : now.day),
            parts.fetch(:hour, 0),
            parts.fetch(:min, 0),
            parts.fetch(:sec, 0) + parts.fetch(:sec_fraction, 0),
            parts.fetch(:offset, 0)
          )
        end

        if parts[:offset] || parts[:seconds]
          TimeWithZone.new(time.utc, self)
        else
          TimeWithZone.new(nil, self, time)
        end
      end

      def time_now
        Time.now
      end
  end
end