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29#include "qcalendar.h"
30#include "qcalendarbackend_p.h"
31#include "qgregoriancalendar_p.h"
32#ifndef QT_BOOTSTRAPPED
33#include "qjuliancalendar_p.h"
34#include "qmilankoviccalendar_p.h"
35#endif
36#if QT_CONFIG(jalalicalendar)
37#include "qjalalicalendar_p.h"
38#endif
39#if QT_CONFIG(islamiccivilcalendar)
40#include "qislamiccivilcalendar_p.h"
41#endif
42
43#include "qatomic.h"
44#include "qdatetime.h"
45#include "qcalendarmath_p.h"
46#include <qhash.h>
47#include <qmutex.h>
48#include <private/qlocking_p.h>
49#include <qdebug.h>
50
51#include <vector>
52
53QT_BEGIN_NAMESPACE
54
55static const QCalendarBackend *backendFromEnum(QCalendar::System system);
56
57namespace {
58
59struct CalendarName : public QString
60{
61 CalendarName(const QString &name) : QString(name) {}
62};
63
64inline bool operator==(const CalendarName &u, const CalendarName &v)
65{
66 return u.compare(s: v, cs: Qt::CaseInsensitive) == 0;
67}
68
69inline uint qHash(const CalendarName &key, uint seed = 0) noexcept
70{
71 return qHash(key: key.toLower(), seed);
72}
73
74static QBasicMutex registryMutex; // Protects registry from concurrent access
75struct Registry
76{
77 std::vector<QCalendarBackend *> byId;
78 QHash<CalendarName, QCalendarBackend *> byName;
79 QAtomicPointer<const QCalendarBackend> gregorianCalendar = nullptr;
80 QAtomicInteger<int> status = 0; // 1: populated, 2: destructing
81
82 Registry()
83 {
84 byId.resize(new_size: int(QCalendar::System::Last) + 1);
85 }
86
87 ~Registry()
88 {
89 status.storeRelaxed(newValue: 2);
90 const auto lock = qt_scoped_lock(mutex&: registryMutex);
91 qDeleteAll(c: byId);
92 }
93
94 bool registerName(QCalendarBackend *calendar, const QString &name)
95 {
96 Q_ASSERT(!name.isEmpty());
97 if (status.loadRelaxed() > 1 || name.isEmpty())
98 return false;
99 const auto lock = qt_scoped_lock(mutex&: registryMutex);
100
101 const auto found = byName.find(akey: name);
102 if (found != byName.end()) {
103 // Re-registering a calendar with a name it has already is OK (and
104 // can be used to test whether its constructor successfully
105 // registered its primary name).
106 return found.value() == calendar;
107 }
108 byName.insert(akey: name, avalue: calendar);
109 return true;
110 }
111 void addCalendar(QCalendarBackend *calendar, const QString &name, QCalendar::System id)
112 {
113 if (status.loadRelaxed() > 1 || name.isEmpty() || !registerName(calendar, name))
114 return;
115 const auto lock = qt_scoped_lock(mutex&: registryMutex);
116 if (id == QCalendar::System::User) {
117 byId.push_back(x: calendar);
118 } else {
119 Q_ASSERT(byId.size() > size_t(id));
120 Q_ASSERT(byId[size_t(id)] == nullptr);
121 byId[size_t(id)] = calendar;
122 }
123 if (id == QCalendar::System::Gregorian) {
124 // We succeeded in registering the name, so must be the first
125 // instantiator of QGregorianCalendar to get here.
126 const bool ok = gregorianCalendar.testAndSetRelease(expectedValue: nullptr, newValue: calendar);
127#if defined(QT_FORCE_ASSERTS) || !defined(QT_NO_DEBUG)
128 Q_ASSERT(ok);
129#else
130 Q_UNUSED(ok);
131#endif
132 }
133 }
134 /*
135 \internal
136 Ensures each \c{enum}-available calendar has been instantiated.
137
138 This arranges for each to register itself by name; it only does anything on
139 its first call, which ensures that name-based lookups can always find all
140 the calendars available via the \c enum.
141 */
142 void populate()
143 {
144 if (status.loadRelaxed())
145 return;
146
147 for (int i = 0; i <= int(QCalendar::System::Last); ++i) {
148 {
149 const auto lock = qt_scoped_lock(mutex&: registryMutex); // so we can check byId[i]
150 if (status.loadRelaxed()) // Might as well check while we're locked
151 return;
152 if (byId[i])
153 continue;
154 }
155 (void)backendFromEnum(system: QCalendar::System(i));
156 }
157
158 status.testAndSetRelease(expectedValue: 0, newValue: 1);
159 }
160};
161
162}
163
164Q_GLOBAL_STATIC(Registry, calendarRegistry);
165
166// Must not be called in a thread that's holding registryMutex locked,
167// since it calls constructors, which need to register.
168static const QCalendarBackend *backendFromEnum(QCalendar::System system)
169{
170 QCalendarBackend *backend = nullptr;
171 switch (system) {
172 case QCalendar::System::Gregorian:
173 backend = new QGregorianCalendar;
174 break;
175#ifndef QT_BOOTSTRAPPED
176 case QCalendar::System::Julian:
177 backend = new QJulianCalendar;
178 break;
179 case QCalendar::System::Milankovic:
180 backend = new QMilankovicCalendar;
181 break;
182#endif
183#if QT_CONFIG(jalalicalendar)
184 case QCalendar::System::Jalali:
185 backend = new QJalaliCalendar;
186 break;
187#endif
188#if QT_CONFIG(islamiccivilcalendar)
189 case QCalendar::System::IslamicCivil:
190 backend = new QIslamicCivilCalendar;
191 break;
192#else // When highest-numbered system isn't enabled, ensure we have a case for Last:
193 case QCalendar::System::Last:
194#endif
195 case QCalendar::System::User:
196 Q_UNREACHABLE();
197 }
198 if (!backend)
199 return backend;
200 const QString name = backend->name();
201 // Check for successful registration:
202 if (calendarRegistry->registerName(calendar: backend, name)) {
203#if defined(QT_FORCE_ASSERTS) || !defined(QT_NO_DEBUG)
204 const auto lock = qt_scoped_lock(mutex&: registryMutex);
205 Q_ASSERT(backend == calendarRegistry->byId[size_t(system)]);
206#endif // else Q_ASSERT() is a no-op and we don't need the lock
207 return backend;
208 }
209 // Duplicate registration: caller can be sure that byId[system] is correctly
210 // set, provided system <= Last.
211 delete backend;
212 return nullptr;
213}
214
215/*!
216 \since 5.14
217
218 \class QCalendarBackend
219 \inmodule QtCore
220 \internal
221 \reentrant
222 \brief The QCalendarBackend class provides basic calendaring functions.
223
224 QCalendarBackend provides the base class on which all calendar types are
225 implemented. On construction, the backend is registered with its primary
226 name.
227
228 A backend, once successfully registered with its primary name, may also be
229 registered with aliases, where the calendar is known by several
230 names. Registering with the name used by CLDR (the Unicode consortium's
231 Common Locale Data Repository) is recommended, particularly when interacting
232 with third-party software. Once a backend is registered for a name,
233 QCalendar can be constructed using that name to select the backend.
234
235 Each built-in backend has a distinct primary name and all built-in backends
236 are instantiated before any custom backend is registered, to prevent custom
237 backends with conflicting names from replacing built-in backends.
238
239 Each calendar backend must inherit from QCalendarBackend and implement its
240 pure virtual methods. It may also override some other virtual methods, as
241 needed.
242
243 Most backends are pure code, with no data elements. Such backends should
244 normally be implemented as singletons. For a backend to be added to the
245 QCalendar::System \c enum, it must be such a singleton, with a case in
246 backendFromEnum()'s switch statement (above) to instantiate it.
247
248 \section1 Instantiating backends
249
250 Backends may be defined by third-party, plugin or user code. When such
251 custom backends are instantiated, in their calls to the QCalendarBackend
252 base-class constructor, each instance should pass a distinct primary name to
253 the base-class constructor and omit the \c system parameter.
254
255 A backend class that has instance variables as well as code may be
256 instantiated many times, each with a distinct primary name, to implement
257 distinct backends - presumably variants on some parameterized calendar.
258 Each instance is then a distinct backend. A pure code backend class shall
259 typically only be instantiated once, as it is only capable of representing
260 one backend.
261
262 Each backend should be instantiated exactly once, on the heap (using the C++
263 \c new operator); this will register it with the QCalendar implementation
264 code and ensure it is available, by its primary name, to all code that may
265 subsequently need it. It will be deleted on program termination along with
266 the registry in which QCalendar records backends.
267
268 The single exception to this is that each backend's instantiator should
269 verify that it was registered successfully with its primary name. It can do
270 this by calling registerAlias() with that name; this will return true if it
271 is already registered with the name. If it returns false, the instantiation
272 has used a name that was already in use so the new backend has not been
273 registered and the instantiator retains ownership of the backend instance;
274 it will not be accessible to QCalendar. (Since registerAlias() is protected,
275 a custom backend's class shall typically need to provide a method to perform
276 this check for its instantiator.)
277
278 Built-in backends, identified by QCalendar::System values other than User,
279 should only be instantiated by code in the implementation of QCalendar; no
280 other code should ever instantiate one. As noted above, such a backend must
281 be a singleton. Its constructor passes down the \c enum member that
282 identifies it as \c system to the base-class constructor.
283
284 The shareable base-classes for backends, QRomanCalendar and QHijriCalendar,
285 are not themselves identified by QCalendar::System and may be used as
286 base-classes for custom calendar backends, but cannot be instantiated
287 themselves.
288
289 \sa registerAlias(), QDate, QDateTime, QDateEdit, QDateTimeEdit,
290 QCalendarWidget
291*/
292
293/*!
294 Constructs the calendar and registers it under \a name using \a system.
295
296 On successful registration, the calendar backend registry takes over
297 ownership of the instance and shall delete it on program exit in the course
298 of the registry's own destruction. The instance can determine whether it was
299 successfully registered by calling registerAlias() with the same \a name it
300 passed to this base-class constructor. If that returns \c false, the
301 instance has not been registered, QCalendar cannot use it, it should not
302 attempt to register any other aliases and the code that instantiated the
303 backend is responsible for deleting it.
304
305 The \a system is optional and should only be passed by built-in
306 implementations of the standard calendars documented in \l
307 QCalendar::System. Custom backends should not pass \a system.
308
309 Only one backend instance should ever be registered for any given \a system:
310 in the event of a backend being created when one with the same \a system
311 already exists, the new backend is not registered. The \a name passed with a
312 \a system (other than \l{QCalendar::System}{User}) must be the \c{name()} of
313 the backend constructed.
314
315 The \a name must be non-empty and unique; after one backend has been
316 registered for a name or alias, no other backend can be registered with that
317 name. The presence of another backend registered with the same name may mean
318 the backend is redundant, as the system already has a backend to handle the
319 given calendar type.
320
321 \note \c{QCalendar(name).isValid()} will return true precisely when the
322 given \c name is in use already. This can be used as a test before
323 instantiating a backend with the given \c name.
324
325 \sa calendarSystem(), registerAlias()
326*/
327QCalendarBackend::QCalendarBackend(const QString &name, QCalendar::System system)
328{
329 Q_ASSERT(!name.isEmpty());
330 // Will lock the registry mutex on its own, so no need to do it here:
331 calendarRegistry->addCalendar(calendar: this, name, id: system);
332}
333
334/*!
335 Destroys the calendar.
336
337 Client code should only call this if instantiation failed to register the
338 backend, as revealed by the instanee failing to registerAlias() with the
339 name it passed to this base-class's constructor. Only a backend that fails
340 to register can safely be deleted; and the client code that instantiated it
341 is indeed responsible for deleting it.
342
343 Once a backend has been successfully registered, there may be QCalendar
344 instances using it; deleting it while they still reference it would lead to
345 undefined behavior. Such a backend shall be deleted when the calendar
346 backend registry is deleted on program exit; the registry takes over
347 ownership of the instance on successful registration.
348
349 \sa registerAlias()
350*/
351QCalendarBackend::~QCalendarBackend()
352{
353 // Either the registry is destroying itself, in which case it takes care of
354 // dropping any references to this, or this never got registered, so there
355 // is no need to tell the registry to forget it.
356}
357
358/*!
359 The calendar system of this calendar.
360
361 Each calendar backend constructible from the QCalendar::System \c enum
362 should return the member of that \c enum that produces it. Other calendars
363 should return User.
364
365 \sa QCalendarBackend::fromEnum()
366*/
367QCalendar::System QCalendarBackend::calendarSystem() const
368{
369 return QCalendar::System::User;
370}
371
372/*!
373 \fn QString QCalendarBackend::name() const;
374
375 This pure virtual method should be overloaded by each backend implementation
376 to return the name that the backend passes to the base-class as its name.
377*/
378
379/*!
380 The primary name of this calendar.
381*/
382QString QCalendar::name() const
383{
384 return d ? d->name() : QString();
385}
386
387// date queries
388/*!
389 \fn int QCalendarBackend::daysInMonth(int month, int year) const
390
391 Returns number of days in the month number \a month, in year \a year.
392
393 An implementation should return 0 if the given year had no such month. If
394 year is QCalendar::Unspecified, return the usual number of days for the
395 month, in those years that include it.
396
397 Calendars with intercallary days may represent these as extra days of the
398 preceding month, or as short months separate from the usual ones. In the
399 former case, daysInMonth(month, year) should be the number of ordinary days
400 in the month, although \c{isDateValid(year, month, day)} might return \c true
401 for some larger values of \c day.
402
403 \sa daysInYear(), monthsInYear(), minimumDaysInMonth(), maximumDaysInMonth()
404*/
405
406// properties of the calendar
407
408/*!
409 \fn bool QCalendarBackend::isLeapYear(int year) const
410
411 Returns \c true if the specified \a year is a leap year for this calendar.
412
413 \sa daysInYear(), isDateValid()
414*/
415
416/*!
417 \fn bool QCalendarBackend::isLunar() const
418
419 Returns \c true if this calendar is a lunar calendar. Otherwise returns \c
420 false.
421
422 A lunar calendar is a calendar based upon the monthly cycles of the Moon's
423 phases (synodic months). This contrasts with solar calendars, whose annual
424 cycles are based only upon the solar year.
425
426 \sa isLuniSolar(), isSolar(), isProleptic()
427*/
428
429/*!
430 \fn bool QCalendarBackend::isLuniSolar() const
431
432 Returns \c true if this calendar is a lunisolar calendar. Otherwise returns
433 \c false.
434
435 A lunisolar calendar is a calendar whose date indicates both the moon phase
436 and the time of the solar year.
437
438 \sa isLunar(), isSolar(), isProleptic()
439*/
440
441/*!
442 \fn bool QCalendarBackend::isSolar() const
443
444 Returns \c true if this calendar is a solar calendar. Otherwise returns
445 \c false.
446
447 A solar calendar is a calendar whose dates indicate the season or almost
448 equivalently the apparent position of the sun relative to the fixed stars.
449 The Gregorian calendar, widely accepted as standard in the world,
450 is an example of solar calendar.
451
452 \sa isLuniSolar(), isLunar(), isProleptic()
453*/
454
455/*!
456 Returns the total number of days in the year number \a year.
457 Returns zero if there is no such year in this calendar.
458
459 This base implementation returns 366 for leap years and 365 for ordinary
460 years.
461
462 \sa monthsInYear(), daysInMonth(), isLeapYear()
463*/
464int QCalendarBackend::daysInYear(int year) const
465{
466 return monthsInYear(year) ? isLeapYear(year) ? 366 : 365 : 0;
467}
468
469/*!
470 Returns the total number of months in the year number \a year.
471 Returns zero if there is no such year in this calendar.
472
473 This base implementation returns 12 for any valid year.
474
475 \sa daysInYear(), maximumMonthsInYear(), isDateValid()
476*/
477int QCalendarBackend::monthsInYear(int year) const
478{
479 return year > 0 || (year < 0 ? isProleptic() : hasYearZero()) ? 12 : 0;
480}
481
482/*!
483 Returns \c true if the date specified by \a year, \a month, and \a day is
484 valid for this calendar; otherwise returns \c false. For example,
485 the date 2018-04-19 is valid for the Gregorian calendar, but 2018-16-19 and
486 2018-04-38 are invalid.
487
488 Calendars with intercallary days may represent these as extra days of the
489 preceding month or as short months separate from the usual ones. In the
490 former case, a \a day value greater than \c{daysInMonth(\a{month},
491 \a{year})} may be valid.
492
493 \sa daysInMonth(), monthsInYear()
494*/
495bool QCalendarBackend::isDateValid(int year, int month, int day) const
496{
497 return day > 0 && day <= daysInMonth(month, year);
498}
499
500/*!
501 Returns \c true if this calendar is a proleptic calendar. Otherwise returns
502 \c false.
503
504 A proleptic calendar results from allowing negative year numbers to indicate
505 years before the nominal start of the calendar system.
506
507 \sa isLuniSolar(), isSolar(), isLunar(), hasYearZero()
508*/
509
510bool QCalendarBackend::isProleptic() const
511{
512 return true;
513}
514
515/*!
516 Returns \c true if year number \c 0 is considered a valid year in this
517 calendar. Otherwise returns \c false.
518
519 \sa isDateValid(), isProleptic()
520*/
521
522bool QCalendarBackend::hasYearZero() const
523{
524 return false;
525}
526
527/*!
528 Returns the maximum number of days in a month for any year.
529
530 This base implementation returns 31, as this is a common case.
531
532 For calendars with intercallary days, although daysInMonth() doesn't include
533 the intercallary days in its count for an individual month,
534 maximumDaysInMonth() should include intercallary days, so that it is the
535 maximum value of \c day for which \c{isDateValid(year, month, day)} can be
536 true.
537
538 \sa maximumMonthsInYear(), daysInMonth()
539*/
540int QCalendarBackend::maximumDaysInMonth() const
541{
542 return 31;
543}
544
545/*!
546 Returns the minimum number of days in any valid month of any valid year.
547
548 This base implementation returns 29, as this is a common case.
549
550 \sa maximumMonthsInYear(), daysInMonth()
551*/
552int QCalendarBackend::minimumDaysInMonth() const
553{
554 return 29;
555}
556
557/*!
558 Returns the maximum number of months possible in any year.
559
560 This base implementation returns 12, as this is a common case.
561
562 \sa maximumDaysInMonth(), monthsInYear()
563*/
564int QCalendarBackend::maximumMonthsInYear() const
565{
566 return 12;
567}
568
569// Julian day number calculations
570
571/*!
572 \fn bool QCalendarBackend::dateToJulianDay(int year, int month, int day, qint64 *jd) const
573
574 Computes the Julian day number corresponding to the specified \a year, \a
575 month, and \a day. Returns true and sets \a jd if there is such a date in
576 this calendar; otherwise, returns false.
577
578 \sa QCalendar::partsFromDate(), julianDayToDate()
579*/
580
581/*!
582 \fn QCalendar::YearMonthDay QCalendarBackend::julianDayToDate(qint64 jd) const
583
584 Computes the year, month, and day in this calendar for the given Julian day
585 number \a jd. If the given day falls outside this calendar's scope
586 (e.g. before the start-date of a non-proleptic calendar), the returned
587 structure's isValid() is false; otherwise, its year, month, and day fields
588 provide this calendar's description of the date.
589
590 \sa QCalendar::dateFromParts(), dateToJulianDay()
591*/
592
593/*!
594 Returns the day of the week for the given Julian Day Number \a jd.
595
596 This is 1 for Monday through 7 for Sunday.
597
598 Calendars with intercallary days may return larger values for these
599 intercallary days. They should avoid using 0 for any special purpose (it is
600 already used in QDate::dayOfWeek() to mean an invalid date). The calendar
601 should treat the numbers used as an \c enum, whose values need not be
602 contiguous, nor need they follow closely from the 1 through 7 of the usual
603 returns. It suffices that weekDayName() can recognize each such number as
604 identifying a distinct name, that it returns to identify the particular
605 intercallary day.
606
607 This base implementation uses the day-numbering that various calendars have
608 borrowed off the Hebrew calendar.
609
610 \sa weekDayName(), standaloneWeekDayName(), QDate::dayOfWeek()
611 */
612int QCalendarBackend::dayOfWeek(qint64 jd) const
613{
614 return QRoundingDown::qMod(a: jd, b: 7) + 1;
615}
616
617// Month and week-day name look-ups (implemented in qlocale.cpp):
618/*!
619 \fn QString QCalendarBackend::monthName(const QLocale &locale, int month, int year,
620 QLocale::FormatType format) const
621
622 Returns the name of the specified \a month in the given \a year for the
623 chosen \a locale, using the given \a format to determine how complete the
624 name is.
625
626 If \a year is Unspecified, return the name for the month that usually has
627 this number within a typical year. Calendars with a leap month that isn't
628 always the last may need to take account of the year to map the month number
629 to the particular year's month with that number.
630
631 \note Backends for which CLDR provides data can configure the default
632 implementation of the two month name look-up methods by arranging for
633 localeMonthIndexData() and localeMonthData() to provide access to the CLDR
634 data (see cldr2qlocalexml.py, qlocalexml2cpp.py and existing backends).
635 Conversely, backends that override both month name look-up methods need not
636 return anything meaningful from localeMonthIndexData() or localeMonthData().
637
638 \sa standaloneMonthName(), QLocale::monthName()
639*/
640
641/*!
642 \fn QString QCalendarBackend::standaloneMonthName(const QLocale &locale, int month, int year
643 QLocale::FormatType format) const
644
645 Returns the standalone name of the specified \a month in the chosen \a
646 locale, using the specified \a format to determine how complete the name is.
647
648 If \a year is Unspecified, return the standalone name for the month that
649 usually has this number within a typical year. Calendars with a leap month
650 that isn't always the last may need to take account of the year to map the
651 month number to the particular year's month with that number.
652
653 \sa monthName(), QLocale::standaloneMonthName()
654*/
655
656/*!
657 \fn QString QCalendarBackend::weekDayName(const QLocale &locale, int day,
658 QLocale::FormatType format) const
659
660 Returns the name of the specified \a day of the week in the chosen \a
661 locale, using the specified \a format to determine how complete the name is.
662
663 The base implementation handles \a day values from 1 to 7 using the day
664 names CLDR provides, which are suitable for calendards that use the same
665 (Hebrew-derived) week as the Gregorian calendar.
666
667 Calendars whose dayOfWeek() returns a value outside the range from 1 to 7
668 need to reimplement this method to handle such extra week-day values. They
669 can assume that \a day is a value returned by the same calendar's
670 dayOfWeek().
671
672 \sa dayOfWeek(), standaloneWeekDayName(), QLocale::dayName()
673*/
674
675/*!
676 \fn QString QCalendarBackend::standaloneWeekDayName(const QLocale &locale, int day,
677 QLocale::FormatType format) const
678
679 Returns the standalone name of the specified \a day of the week in the
680 chosen \a locale, using the specified \a format to determine how complete
681 the name is.
682
683 The base implementation handles \a day values from 1 to 7 using the
684 standalone day names CLDR provides, which are suitable for calendards that
685 use the same (Hebrew-derived) week as the Gregorian calendar.
686
687 Calendars whose dayOfWeek() returns a value outside the range from 1 to 7
688 need to reimplement this method to handle such extra week-day values. They
689 can assume that \a day is a value returned by the same calendar's
690 dayOfWeek().
691
692 \sa dayOfWeek(), weekDayName(), QLocale::standaloneDayName()
693*/
694
695/*!
696 \fn QString QCalendarBackend::dateTimeToString(QStringView format, const QDateTime &datetime,
697 const QDate &dateOnly, const QTime &timeOnly,
698 const QLocale &locale) const
699
700 Returns a string representing a given date, time or date-time.
701
702 If \a datetime is specified and valid, it is used and both date and time
703 format tokens are converted to appropriate representations of the parts of
704 the datetime. Otherwise, if \a dateOnly is valid, only date format tokens
705 are converted; else, if \a timeOnly is valid, only time format tokens are
706 converted. If none are valid, an empty string is returned.
707
708 The specified \a locale influences how some format tokens are converted; for
709 example, when substituting day and month names and their short-forms. For
710 the supported formatting tokens, see QDate::toString() and
711 QTime::toString(). As described above, the provided date, time and date-time
712 determine which of these tokens are recognized: where these appear in \a
713 format they are replaced by data. Any text in \a format not recognized as a
714 format token is copied verbatim into the result string.
715
716 \sa QDate::toString(), QTime::toString(), QDateTime::toString()
717*/
718// End of methods implemented in qlocale.cpp
719
720/*!
721 Returns a list of names of the available calendar systems. Any
722 QCalendarBackend sub-class must be registered before being exposed to Date
723 and Time APIs.
724
725 \sa registerAlias(), fromName()
726*/
727QStringList QCalendarBackend::availableCalendars()
728{
729 if (calendarRegistry.isDestroyed())
730 return {};
731 calendarRegistry->populate();
732 const auto registryLock = qt_scoped_lock(mutex&: registryMutex);
733 return QStringList(calendarRegistry->byName.keyBegin(), calendarRegistry->byName.keyEnd());
734}
735
736/*!
737 Registers an alias for this calendar backend. Once a backend is registered,
738 its name will be included in the list of available calendars and the
739 calendar can be instantiated by name.
740
741 Returns \c false if the given \a name is already in use by a different
742 backend or \c true if this calendar is already registered with this
743 name. (This can be used, with its primary name, to test whether a backend's
744 construction successfully registered it.) Otherwise it registers this
745 calendar backend for this name and returns \c true.
746
747 \sa availableCalendars(), fromName()
748*/
749bool QCalendarBackend::registerAlias(const QString &name)
750{
751 if (calendarRegistry.isDestroyed() || name.isEmpty())
752 return false;
753 // Constructing this accessed the registry, so ensured it exists:
754 Q_ASSERT(calendarRegistry.exists());
755
756 // Not taking the lock on the registry here because it's just one call
757 // (which internally locks anyway).
758 return calendarRegistry->registerName(calendar: this, name);
759}
760
761/*!
762 \internal
763 Returns a pointer to a named calendar backend.
764
765 If the given \a name is present in availableCalendars(), the backend
766 matching it is returned; otherwise, \c nullptr is returned. Matching of
767 names ignores case. Note that this won't provoke construction of a calendar
768 backend, it will only return ones that have been instantiated (and not yet
769 destroyed) by some other means. However, calendars available via the
770 QCalendar::System \c enum are always registered when this is called.
771
772 \sa availableCalendars(), registerAlias(), fromEnum()
773*/
774const QCalendarBackend *QCalendarBackend::fromName(QStringView name)
775{
776 if (calendarRegistry.isDestroyed())
777 return nullptr;
778 calendarRegistry->populate();
779 const auto registryLock = qt_scoped_lock(mutex&: registryMutex);
780 auto it = calendarRegistry->byName.find(akey: name.toString());
781 return it == calendarRegistry->byName.end() ? nullptr : *it;
782}
783
784/*!
785 \internal
786 \overload
787 */
788const QCalendarBackend *QCalendarBackend::fromName(QLatin1String name)
789{
790 if (calendarRegistry.isDestroyed())
791 return nullptr;
792 calendarRegistry->populate();
793 const auto registryLock = qt_scoped_lock(mutex&: registryMutex);
794 auto it = calendarRegistry->byName.find(akey: QString(name));
795 return it == calendarRegistry->byName.end() ? nullptr : *it;
796}
797
798/*!
799 \internal
800 Returns a pointer to a calendar backend, specified by \c enum.
801
802 This will instantiate the indicated calendar (which will enable fromName()
803 to return it subsequently), but only for the Qt-supported calendars for
804 which (where relevant) the appropriate feature has been enabled.
805*/
806const QCalendarBackend *QCalendarBackend::fromEnum(QCalendar::System system)
807{
808 if (calendarRegistry.isDestroyed() || system == QCalendar::System::User)
809 return nullptr;
810 {
811 const auto registryLock = qt_scoped_lock(mutex&: registryMutex);
812 Q_ASSERT(calendarRegistry->byId.size() >= size_t(system));
813 if (auto *c = calendarRegistry->byId[size_t(system)])
814 return c;
815 }
816 if (auto *result = backendFromEnum(system))
817 return result;
818 const auto registryLock = qt_scoped_lock(mutex&: registryMutex);
819 return calendarRegistry->byId[size_t(system)];
820}
821
822/*!
823 \since 5.14
824
825 \class QCalendar
826 \inmodule QtCore
827 \reentrant
828 \brief The QCalendar class describes calendar systems.
829
830 A QCalendar object maps a year, month, and day-number to a specific day
831 (ultimately identified by its Julian day number), using the rules of a
832 particular system.
833
834 The default QCalendar() is a proleptic Gregorian calendar, which has no year
835 zero. Other calendars may be supported by enabling suitable features or
836 loading plugins. Calendars supported as features can be constructed by
837 passing the QCalendar::System enumeration to the constructor. All supported
838 calendars may be constructed by name, once they have been constructed. (Thus
839 plugins instantiate their calendar backend to register it.) Built-in
840 backends, accessible via QCalendar::System, are also always available by
841 name.
842
843 A QCalendar value is immutable.
844
845 \sa QDate, QDateTime
846*/
847
848/*!
849 \enum QCalendar::System
850
851 This enumerated type is used to specify a choice of calendar system.
852
853 \value Gregorian The default calendar, used internationally.
854 \value Julian An ancient Roman calendar.
855 \value Milankovic A revised Julian calendar used by some Orthodox churches.
856 \value Jalali The Solar Hijri calendar (also called Persian).
857 \value IslamicCivil The (tabular) Islamic Civil calendar.
858 \omitvalue Last
859 \omitvalue User
860
861 \sa QCalendar
862*/
863
864/*!
865 \fn QCalendar::QCalendar()
866 \fn QCalendar::QCalendar(QCalendar::System system)
867 \fn QCalendar::QCalendar(QLatin1String name)
868 \fn QCalendar::QCalendar(QStringView name)
869
870 Constructs a calendar object.
871
872 The choice of calendar to use may be indicated as \a system, using the
873 enumeration QCalendar::System, or by \a name, using a string (either Unicode
874 or Latin 1). Construction by name may depend on an instance of the given
875 calendar being constructed by other means first. With no argument, the
876 default constructor returns the Gregorian calendar.
877
878 \sa QCalendar, System, isValid()
879*/
880
881QCalendar::QCalendar()
882 : d(nullptr)
883{
884 if (calendarRegistry.isDestroyed())
885 return;
886 d = calendarRegistry->gregorianCalendar.loadAcquire();
887 if (!d) {
888 auto fresh = new QGregorianCalendar;
889 if (!calendarRegistry->gregorianCalendar.testAndSetOrdered(expectedValue: fresh, newValue: fresh, currentValue&: d))
890 delete fresh;
891 Q_ASSERT(d);
892 }
893}
894
895QCalendar::QCalendar(QCalendar::System system)
896 : d(QCalendarBackend::fromEnum(system))
897{
898 // If system is valid, we should get a valid d for that system.
899 Q_ASSERT(uint(system) > uint(QCalendar::System::Last) || (d && d->calendarSystem() == system));
900}
901
902QCalendar::QCalendar(QLatin1String name)
903 : d(QCalendarBackend::fromName(name)) {}
904
905QCalendar::QCalendar(QStringView name)
906 : d(QCalendarBackend::fromName(name)) {}
907
908/*!
909 \fn bool QCalendar::isValid() const
910
911 Returns true if this is a valid calendar object.
912
913 Constructing a calendar with an unrecognised calendar name may result in an
914 invalid object. Use this method to check after creating a calendar by name.
915*/
916
917// Date queries:
918
919/*!
920 Returns the number of days in the given \a month of the given \a year.
921
922 Months are numbered consecutively, starting with 1 for the first month of
923 each year. If \a year is \c Unspecified (its default, if not passed), the
924 month's length in a normal year is returned.
925
926 \sa maximumDaysInMonth(), minimumDaysInMonth()
927*/
928int QCalendar::daysInMonth(int month, int year) const
929{
930 return d ? d->daysInMonth(month, year) : 0;
931}
932
933/*!
934 Returns the number of days in the given \a year.
935
936 Handling of \c Unspecified as \a year is undefined.
937*/
938int QCalendar::daysInYear(int year) const
939{
940 return d ? d->daysInYear(year) : 0;
941}
942
943/*!
944 Returns the number of months in the given \a year.
945
946 If \a year is \c Unspecified, returns the maximum number of months in a
947 year.
948
949 \sa maximumMonthsInYear()
950*/
951int QCalendar::monthsInYear(int year) const
952{
953 return d ? year == Unspecified ? d->maximumMonthsInYear() : d->monthsInYear(year) : 0;
954}
955
956/*!
957 Returns \c true precisely if the given \a year, \a month, and \a day specify
958 a valid date in this calendar.
959
960 Usually this means 1 <= month <= monthsInYear(year) and 1 <= day <=
961 daysInMonth(month, year). However, calendars with intercallary days or
962 months may complicate that.
963*/
964bool QCalendar::isDateValid(int year, int month, int day) const
965{
966 return d && d->isDateValid(year, month, day);
967}
968
969// properties of the calendar
970
971/*!
972 Returns \c true if this calendar object is the Gregorian calendar object
973 used as default calendar by other Qt APIs, e.g. in QDate.
974*/
975bool QCalendar::isGregorian() const
976{
977 Q_ASSERT(calendarRegistry.exists());
978 return d == calendarRegistry->gregorianCalendar.loadRelaxed();
979}
980
981/*!
982 Returns \c true if the given \a year is a leap year.
983
984 Since the year is not a whole number of days long, some years are longer
985 than others. The difference may be a whole month or just a single day; the
986 details vary between calendars.
987
988 \sa isDateValid()
989*/
990bool QCalendar::isLeapYear(int year) const
991{
992 return d && d->isLeapYear(year);
993}
994
995/*!
996 Returns \c true if this calendar is a lunar calendar.
997
998 A lunar calendar is one based primarily on the phases of the moon.
999*/
1000bool QCalendar::isLunar() const
1001{
1002 return d && d->isLunar();
1003}
1004
1005/*!
1006 Returns \c true if this calendar is luni-solar.
1007
1008 A luni-solar calendar expresses the phases of the moon but adapts itself to
1009 also keep track of the Sun's varying position in the sky, relative to the
1010 fixed stars.
1011*/
1012bool QCalendar::isLuniSolar() const
1013{
1014 return d && d->isLuniSolar();
1015}
1016
1017/*!
1018 Returns \c true if this calendar is solar.
1019
1020 A solar calendar is based primarily on the Sun's varying position in the
1021 sky, relative to the fixed stars.
1022*/
1023bool QCalendar::isSolar() const
1024{
1025 return d && d->isSolar();
1026}
1027
1028/*!
1029 Returns \c true if this calendar is proleptic.
1030
1031 A proleptic calendar is able to describe years arbitrarily long before its
1032 first. These are represented by negative year numbers and possibly by a year
1033 zero.
1034
1035 \sa hasYearZero()
1036*/
1037bool QCalendar::isProleptic() const
1038{
1039 return d && d->isProleptic();
1040}
1041
1042/*!
1043 Returns \c true if this calendar has a year zero.
1044
1045 A calendar may represent years from its first year onwards but provide no
1046 way to describe years before its first; such a calendar has no year zero and
1047 is not proleptic.
1048
1049 A calendar which represents years before its first may number these years
1050 simply by following the usual integer counting, so that the year before the
1051 first is year zero, with negative-numbered years preceding this; such a
1052 calendar is proleptic and has a year zero. A calendar might also have a year
1053 zero (for example, the year of some great event, with subsequent years being
1054 the first year after that event, the second year after, and so on) without
1055 describing years before its year zero. Such a calendar would have a year
1056 zero without being proleptic.
1057
1058 Some calendars, however, represent years before their first by an alternate
1059 numbering; for example, the proleptic Gregorian calendar's first year is 1
1060 CE and the year before it is 1 BCE, preceded by 2 BCE and so on. In this
1061 case, we use negative year numbers for this alternate numbering, with year
1062 -1 as the year before year 1, year -2 as the year before year -1 and so
1063 on. Such a calendar is proleptic but has no year zero.
1064
1065 \sa isProleptic()
1066*/
1067bool QCalendar::hasYearZero() const
1068{
1069 return d && d->hasYearZero();
1070}
1071
1072/*!
1073 Returns the number of days in the longest month in the calendar, in any year.
1074
1075 \sa daysInMonth(), minimumDaysInMonth()
1076*/
1077int QCalendar::maximumDaysInMonth() const
1078{
1079 return d ? d->maximumDaysInMonth() : 0;
1080}
1081
1082/*!
1083 Returns the number of days in the shortest month in the calendar, in any year.
1084
1085 \sa daysInMonth(), maximumDaysInMonth()
1086*/
1087int QCalendar::minimumDaysInMonth() const
1088{
1089 return d ? d->minimumDaysInMonth() : 0;
1090}
1091
1092/*!
1093 Returns the largest number of months that any year may contain.
1094
1095 \sa monthName(), standaloneMonthName(), monthsInYear()
1096*/
1097int QCalendar::maximumMonthsInYear() const
1098{
1099 return d ? d->maximumMonthsInYear() : 0;
1100}
1101
1102// Julian Day conversions:
1103
1104/*!
1105 \fn QDate QCalendar::dateFromParts(int year, int month, int day) const
1106 \fn QDate QCalendar::dateFromParts(const QCalendar::YearMonthDay &parts) const
1107
1108 Converts a year, month, and day to a QDate.
1109
1110 The \a year, \a month, and \a day may be passed as separate numbers or
1111 packaged together as the members of \a parts. Returns a QDate with the given
1112 year, month, and day of the month in this calendar, if there is one.
1113 Otherwise, including the case where any of the values is
1114 QCalendar::Unspecified, returns a QDate whose isNull() is true.
1115
1116 \sa isDateValid(), partsFromDate()
1117*/
1118QDate QCalendar::dateFromParts(int year, int month, int day) const
1119{
1120 qint64 jd;
1121 return d && d->dateToJulianDay(year, month, day, jd: &jd)
1122 ? QDate::fromJulianDay(jd_: jd) : QDate();
1123}
1124
1125QDate QCalendar::dateFromParts(const QCalendar::YearMonthDay &parts) const
1126{
1127 return parts.isValid() ? dateFromParts(year: parts.year, month: parts.month, day: parts.day) : QDate();
1128}
1129
1130/*!
1131 Converts a QDate to a year, month, and day of the month.
1132
1133 The returned structure's isValid() shall be false if the calendar is unable
1134 to represent the given \a date. Otherwise its year, month, and day
1135 members record the so-named parts of its representation.
1136
1137 \sa dateFromParts(), isProleptic(), hasYearZero()
1138*/
1139QCalendar::YearMonthDay QCalendar::partsFromDate(QDate date) const
1140{
1141 return d && date.isValid() ? d->julianDayToDate(jd: date.toJulianDay()) : YearMonthDay();
1142}
1143
1144/*!
1145 Returns the day of the week number for the given \a date.
1146
1147 Returns zero if the calendar is unable to represent the indicated date.
1148 Returns 1 for Monday through 7 for Sunday. Calendars with intercallary days
1149 may use other numbers to represent these.
1150
1151 \sa partsFromDate(), Qt::DayOfWeek
1152*/
1153int QCalendar::dayOfWeek(QDate date) const
1154{
1155 return d && date.isValid() ? d->dayOfWeek(jd: date.toJulianDay()) : 0;
1156}
1157
1158// Locale data access
1159
1160/*!
1161 Returns a suitably localised name for a month.
1162
1163 The month is indicated by a number, with \a month = 1 meaning the first
1164 month of the year and subsequent months numbered accordingly. Returns an
1165 empty string if the \a month number is unrecognized.
1166
1167 The \a year may be Unspecified, in which case the mapping from numbers to
1168 names for a typical year's months should be used. Some calendars have leap
1169 months that aren't always at the end of the year; their mapping of month
1170 numbers to names may then depend on the placement of a leap month. Thus the
1171 year should normally be specified, if known.
1172
1173 The name is returned in the form that would normally be used in a full date,
1174 in the specified \a locale; the \a format determines how fully it shall be
1175 expressed (i.e. to what extent it is abbreviated).
1176
1177 \sa standaloneMonthName(), maximumMonthsInYear(), dateTimeToString()
1178*/
1179QString QCalendar::monthName(const QLocale &locale, int month, int year,
1180 QLocale::FormatType format) const
1181{
1182 const int maxMonth = year == Unspecified ? maximumMonthsInYear() : monthsInYear(year);
1183 if (!d || month < 1 || month > maxMonth)
1184 return QString();
1185
1186 return d->monthName(locale, month, year, format);
1187}
1188
1189/*!
1190 Returns a suitably localised standalone name for a month.
1191
1192 The month is indicated by a number, with \a month = 1 meaning the first
1193 month of the year and subsequent months numbered accordingly. Returns an
1194 empty string if the \a month number is unrecognized.
1195
1196 The \a year may be Unspecified, in which case the mapping from numbers to
1197 names for a typical year's months should be used. Some calendars have leap
1198 months that aren't always at the end of the year; their mapping of month
1199 numbers to names may then depend on the placement of a leap month. Thus the
1200 year should normally be specified, if known.
1201
1202 The name is returned in the form that would be used in isolation in the
1203 specified \a locale; the \a format determines how fully it shall be
1204 expressed (i.e. to what extent it is abbreviated).
1205
1206 \sa monthName(), maximumMonthsInYear(), dateTimeToString()
1207*/
1208QString QCalendar::standaloneMonthName(const QLocale &locale, int month, int year,
1209 QLocale::FormatType format) const
1210{
1211 const int maxMonth = year == Unspecified ? maximumMonthsInYear() : monthsInYear(year);
1212 if (!d || month < 1 || month > maxMonth)
1213 return QString();
1214
1215 return d->standaloneMonthName(locale, month, year, format);
1216}
1217
1218/*!
1219 Returns a suitably localised name for a day of the week.
1220
1221 The days of the week are numbered from 1 for Monday through 7 for
1222 Sunday. Some calendars may support higher numbers for other days
1223 (e.g. intercallary days, that are not part of any week). Returns an empty
1224 string if the \a day number is unrecognized.
1225
1226 The name is returned in the form that would normally be used in a full date,
1227 in the specified \a locale; the \a format determines how fully it shall be
1228 expressed (i.e. to what extent it is abbreviated).
1229
1230 \sa standaloneWeekDayName(), dayOfWeek()
1231*/
1232QString QCalendar::weekDayName(const QLocale &locale, int day,
1233 QLocale::FormatType format) const
1234{
1235 return d ? d->weekDayName(locale, day, format) : QString();
1236}
1237
1238/*!
1239 Returns a suitably localised standalone name for a day of the week.
1240
1241 The days of the week are numbered from 1 for Monday through 7 for
1242 Sunday. Some calendars may support higher numbers for other days
1243 (e.g. intercallary days, that are not part of any week). Returns an empty
1244 string if the \a day number is unrecognized.
1245
1246 The name is returned in the form that would be used in isolation (for
1247 example as a column heading in a calendar's tabular display of a month with
1248 successive weeks as rows) in the specified \a locale; the \a format
1249 determines how fully it shall be expressed (i.e. to what extent it is
1250 abbreviated).
1251
1252 \sa weekDayName(), dayOfWeek()
1253*/
1254QString QCalendar::standaloneWeekDayName(const QLocale &locale, int day,
1255 QLocale::FormatType format) const
1256{
1257 return d ? d->standaloneWeekDayName(locale, day, format) : QString();
1258}
1259
1260/*!
1261 Returns a string representing a given date, time or date-time.
1262
1263 If \a datetime is valid, it is represented and format specifiers for both
1264 date and time fields are recognized; otherwise, if \a dateOnly is valid, it
1265 is represented and only format specifiers for date fields are recognized;
1266 finally, if \a timeOnly is valid, it is represented and only format
1267 specifiers for time fields are recognized. If none of these is valid, an
1268 empty string is returned.
1269
1270 See QDate::toString and QTime::toString() for the supported field
1271 specifiers. Characters in \a format that are recognized as field specifiers
1272 are replaced by text representing appropriate data from the date and/or time
1273 being represented. The texts to represent them may depend on the \a locale
1274 specified. Other charagers in \a format are copied verbatim into the
1275 returned string.
1276
1277 \sa monthName(), weekDayName(), QDate::toString(), QTime::toString()
1278*/
1279QString QCalendar::dateTimeToString(QStringView format, const QDateTime &datetime,
1280 const QDate &dateOnly, const QTime &timeOnly,
1281 const QLocale &locale) const
1282{
1283 return d ? d->dateTimeToString(format, datetime, dateOnly, timeOnly, locale) : QString();
1284}
1285
1286/*!
1287 Returns a list of names of the available calendar systems.
1288
1289 These may be supplied by plugins or other code linked into an application,
1290 in addition to the ones provided by Qt, some of which are controlled by
1291 features.
1292*/
1293QStringList QCalendar::availableCalendars()
1294{
1295 return QCalendarBackend::availableCalendars();
1296}
1297
1298QT_END_NAMESPACE
1299
1300#ifndef QT_BOOTSTRAPPED
1301#include "moc_qcalendar.cpp"
1302#endif
1303

source code of qtbase/src/corelib/time/qcalendar.cpp