f071d4ee8a
This example demonstrates how to write a calendar backend plugin using a low-level API for extending Qt applications. Fixes: QTBUG-115200 Change-Id: If0b7f2552ba8c2203acdcbff238fb0ffa7cfca55 Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
104 lines
3.9 KiB
C++
104 lines
3.9 KiB
C++
// Copyright (C) 2024 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
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#include "calendarbackend.h"
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#include <QCalendar>
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JulianGregorianCalendar::JulianGregorianCalendar(QDate endJulian, QAnyStringView name = {})
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: m_julianUntil(julian.partsFromDate(endJulian)),
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m_gregorianSince(gregorian.partsFromDate(endJulian.addDays(1))),
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m_name(name.isEmpty()
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? endJulian.toString(u"Julian until yyyy-MM-dd", julian)
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: name.toString())
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{
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Q_ASSERT_X(m_julianUntil.year < m_gregorianSince.year
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|| (m_julianUntil.year == m_gregorianSince.year
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&& (m_julianUntil.month < m_gregorianSince.month
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|| (m_julianUntil.month == m_gregorianSince.month
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&& m_julianUntil.day < m_gregorianSince.day))),
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"JulianGregorianCalendar::JulianGregorianCalendar()",
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"Perversely early date for Julian-to-Gregorian transition");
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}
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QString JulianGregorianCalendar::name() const
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{
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return QStringLiteral("JulianGregorian");
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}
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int JulianGregorianCalendar::daysInMonth(int month, int year) const
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{
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if (year == QCalendar::Unspecified)
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return QRomanCalendar::daysInMonth(month, year);
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if (year < m_julianUntil.year
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|| (year == m_julianUntil.year && month < m_julianUntil.month)) {
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return julian.daysInMonth(month, year);
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}
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if ((year > m_gregorianSince.year)
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|| (year == m_gregorianSince.year && month > m_gregorianSince.month)) {
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return gregorian.daysInMonth(month, year);
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}
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if (m_julianUntil.year == m_gregorianSince.year) {
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Q_ASSERT(year == m_julianUntil.year);
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if (m_julianUntil.month == m_gregorianSince.month) {
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Q_ASSERT(month == m_julianUntil.month);
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return QRomanCalendar::daysInMonth(month, year)
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+ m_julianUntil.day - m_gregorianSince.day + 1;
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}
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}
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if (year == m_julianUntil.year && month == m_julianUntil.month)
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return m_julianUntil.day;
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if (year == m_gregorianSince.year && month == m_gregorianSince.month)
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return gregorian.daysInMonth(month, year) + 1 - m_gregorianSince.day;
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Q_ASSERT(year > 3900);
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return 0;
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}
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bool JulianGregorianCalendar::isLeapYear(int year) const
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{
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if (year < m_julianUntil.year
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|| (year == m_julianUntil.year
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&& (m_julianUntil.month > 2
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|| (m_julianUntil.month == 2 && m_julianUntil.day == 29)))) {
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return julian.isLeapYear(year);
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}
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return gregorian.isLeapYear(year);
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}
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//![0]
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bool JulianGregorianCalendar::dateToJulianDay(int year, int month, int day, qint64 *jd) const
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{
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if (year == m_julianUntil.year && month == m_julianUntil.month) {
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if (m_julianUntil.day < day && day < m_gregorianSince.day) {
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// Requested date is in the gap skipped over by the transition.
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*jd = 0;
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return false;
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}
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}
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QDate givenDate = gregorian.dateFromParts(year, month, day);
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QDate julianUntil = julian.dateFromParts(m_julianUntil);
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if (givenDate > julianUntil) {
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*jd = givenDate.toJulianDay();
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return true;
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}
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*jd = julian.dateFromParts(year, month, day).toJulianDay();
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return true;
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}
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//![0]
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//![1]
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QCalendar::YearMonthDay JulianGregorianCalendar::julianDayToDate(qint64 jd) const
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{
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const qint64 jdForChange = julian.dateFromParts(m_julianUntil).toJulianDay();
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if (jdForChange < jd) {
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QCalendar gregorian(QCalendar::System::Gregorian);
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QDate date = QDate::fromJulianDay(jd);
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return gregorian.partsFromDate(date);
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} else if (jd <= jdForChange) {
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QCalendar julian(QCalendar::System::Julian);
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QDate date = QDate::fromJulianDay(jd);
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return julian.partsFromDate(date);
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}
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return QCalendar::YearMonthDay(QCalendar::Unspecified, QCalendar::Unspecified,
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QCalendar::Unspecified);
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}
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//![1]
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