LibJS+LibTimeZone+LibUnicode: Indicate whether a time zone is in DST

Return whether the time zone is in DST during the provided time from
TimeZone::get_time_zone_offset,
This commit is contained in:
Timothy Flynn 2022-01-19 14:18:02 -05:00 committed by Linus Groh
parent 42c9c57141
commit 70f49d0696
Notes: sideshowbarker 2024-07-17 20:37:43 +09:00
7 changed files with 86 additions and 69 deletions

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@ -450,7 +450,7 @@ static constexpr Array<@type@, @size@> @name@ { {
append_string_conversions("DaylightSavingsRule"sv, "daylight_savings_rule"sv, time_zone_data.dst_offset_names);
generator.append(R"~~~(
static i64 get_dst_offset(TimeZoneOffset const& time_zone_offset, AK::Time time)
static Offset get_dst_offset(TimeZoneOffset const& time_zone_offset, AK::Time time)
{
auto const& dst_rules = s_dst_offsets[time_zone_offset.dst_rule];
@ -487,17 +487,17 @@ static i64 get_dst_offset(TimeZoneOffset const& time_zone_offset, AK::Time time)
}
if (!standard_offset || !daylight_offset)
return 0;
return {};
auto standard_time_in_effect = time_in_effect_for_rule(*standard_offset);
auto daylight_time_in_effect = time_in_effect_for_rule(*daylight_offset);
if ((time < daylight_time_in_effect) || (time >= standard_time_in_effect))
return standard_offset->offset;
return daylight_offset->offset;
return { standard_offset->offset, InDST::No };
return { daylight_offset->offset, InDST::Yes };
}
Optional<i64> get_time_zone_offset(TimeZone time_zone, AK::Time time)
Optional<Offset> get_time_zone_offset(TimeZone time_zone, AK::Time time)
{
auto const& time_zone_offsets = s_time_zone_offsets[to_underlying(time_zone)];
@ -512,13 +512,16 @@ Optional<i64> get_time_zone_offset(TimeZone time_zone, AK::Time time)
VERIFY(index < time_zone_offsets.size());
auto const& time_zone_offset = time_zone_offsets[index];
i64 dst_offset = 0;
if (time_zone_offset.dst_rule != -1)
Offset dst_offset {};
if (time_zone_offset.dst_rule != -1) {
dst_offset = get_dst_offset(time_zone_offset, time);
else
dst_offset = time_zone_offset.dst_offset;
} else {
auto in_dst = time_zone_offset.dst_offset == 0 ? InDST::No : InDST::Yes;
dst_offset = { time_zone_offset.dst_offset, in_dst };
}
return time_zone_offset.offset + dst_offset;
dst_offset.seconds += time_zone_offset.offset;
return dst_offset;
}
}

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@ -10,6 +10,8 @@
#include <AK/Time.h>
#include <LibTimeZone/TimeZone.h>
using enum TimeZone::InDST;
#if ENABLE_TIME_ZONE_DATA
# include <LibTimeZone/TimeZoneData.h>
@ -90,60 +92,61 @@ static i64 offset(i64 sign, i64 hours, i64 minutes, i64 seconds)
return sign * ((hours * 3600) + (minutes * 60) + seconds);
}
static void test_offset(StringView time_zone, i64 time, i64 expected_offset)
static void test_offset(StringView time_zone, i64 time, i64 expected_offset, TimeZone::InDST expected_in_dst)
{
auto actual_offset = TimeZone::get_time_zone_offset(time_zone, AK::Time::from_seconds(time));
VERIFY(actual_offset.has_value());
EXPECT_EQ(*actual_offset, expected_offset);
EXPECT_EQ(actual_offset->seconds, expected_offset);
EXPECT_EQ(actual_offset->in_dst, expected_in_dst);
}
TEST_CASE(get_time_zone_offset)
{
test_offset("America/Chicago"sv, -2717668237, offset(-1, 5, 50, 36)); // Sunday, November 18, 1883 12:09:23 PM
test_offset("America/Chicago"sv, -2717668236, offset(-1, 6, 00, 00)); // Sunday, November 18, 1883 12:09:24 PM
test_offset("America/Chicago"sv, -1067810460, offset(-1, 6, 00, 00)); // Sunday, March 1, 1936 1:59:00 AM
test_offset("America/Chicago"sv, -1067810400, offset(-1, 5, 00, 00)); // Sunday, March 1, 1936 2:00:00 AM
test_offset("America/Chicago"sv, -1045432860, offset(-1, 5, 00, 00)); // Sunday, November 15, 1936 1:59:00 AM
test_offset("America/Chicago"sv, -1045432800, offset(-1, 6, 00, 00)); // Sunday, November 15, 1936 2:00:00 AM
test_offset("America/Chicago"sv, -2717668237, offset(-1, 5, 50, 36), No); // Sunday, November 18, 1883 12:09:23 PM
test_offset("America/Chicago"sv, -2717668236, offset(-1, 6, 00, 00), No); // Sunday, November 18, 1883 12:09:24 PM
test_offset("America/Chicago"sv, -1067810460, offset(-1, 6, 00, 00), No); // Sunday, March 1, 1936 1:59:00 AM
test_offset("America/Chicago"sv, -1067810400, offset(-1, 5, 00, 00), No); // Sunday, March 1, 1936 2:00:00 AM
test_offset("America/Chicago"sv, -1045432860, offset(-1, 5, 00, 00), No); // Sunday, November 15, 1936 1:59:00 AM
test_offset("America/Chicago"sv, -1045432800, offset(-1, 6, 00, 00), No); // Sunday, November 15, 1936 2:00:00 AM
test_offset("Europe/London"sv, -3852662401, offset(-1, 0, 01, 15)); // Tuesday, November 30, 1847 11:59:59 PM
test_offset("Europe/London"sv, -3852662400, offset(+1, 0, 00, 00)); // Wednesday, December 1, 1847 12:00:00 AM
test_offset("Europe/London"sv, -37238401, offset(+1, 0, 00, 00)); // Saturday, October 26, 1968 11:59:59 PM
test_offset("Europe/London"sv, -37238400, offset(+1, 1, 00, 00)); // Sunday, October 27, 1968 12:00:00 AM
test_offset("Europe/London"sv, 57722399, offset(+1, 1, 00, 00)); // Sunday, October 31, 1971 1:59:59 AM
test_offset("Europe/London"sv, 57722400, offset(+1, 0, 00, 00)); // Sunday, October 31, 1971 2:00:00 AM
test_offset("Europe/London"sv, -3852662401, offset(-1, 0, 01, 15), No); // Tuesday, November 30, 1847 11:59:59 PM
test_offset("Europe/London"sv, -3852662400, offset(+1, 0, 00, 00), No); // Wednesday, December 1, 1847 12:00:00 AM
test_offset("Europe/London"sv, -37238401, offset(+1, 0, 00, 00), No); // Saturday, October 26, 1968 11:59:59 PM
test_offset("Europe/London"sv, -37238400, offset(+1, 1, 00, 00), No); // Sunday, October 27, 1968 12:00:00 AM
test_offset("Europe/London"sv, 57722399, offset(+1, 1, 00, 00), No); // Sunday, October 31, 1971 1:59:59 AM
test_offset("Europe/London"sv, 57722400, offset(+1, 0, 00, 00), No); // Sunday, October 31, 1971 2:00:00 AM
test_offset("UTC"sv, -1641846268, offset(+1, 0, 00, 00));
test_offset("UTC"sv, 0, offset(+1, 0, 00, 00));
test_offset("UTC"sv, 1641846268, offset(+1, 0, 00, 00));
test_offset("UTC"sv, -1641846268, offset(+1, 0, 00, 00), No);
test_offset("UTC"sv, 0, offset(+1, 0, 00, 00), No);
test_offset("UTC"sv, 1641846268, offset(+1, 0, 00, 00), No);
test_offset("Etc/GMT+4"sv, -1641846268, offset(-1, 4, 00, 00));
test_offset("Etc/GMT+5"sv, 0, offset(-1, 5, 00, 00));
test_offset("Etc/GMT+6"sv, 1641846268, offset(-1, 6, 00, 00));
test_offset("Etc/GMT+4"sv, -1641846268, offset(-1, 4, 00, 00), No);
test_offset("Etc/GMT+5"sv, 0, offset(-1, 5, 00, 00), No);
test_offset("Etc/GMT+6"sv, 1641846268, offset(-1, 6, 00, 00), No);
test_offset("Etc/GMT-12"sv, -1641846268, offset(+1, 12, 00, 00));
test_offset("Etc/GMT-13"sv, 0, offset(+1, 13, 00, 00));
test_offset("Etc/GMT-14"sv, 1641846268, offset(+1, 14, 00, 00));
test_offset("Etc/GMT-12"sv, -1641846268, offset(+1, 12, 00, 00), No);
test_offset("Etc/GMT-13"sv, 0, offset(+1, 13, 00, 00), No);
test_offset("Etc/GMT-14"sv, 1641846268, offset(+1, 14, 00, 00), No);
EXPECT(!TimeZone::get_time_zone_offset("I don't exist"sv, {}).has_value());
}
TEST_CASE(get_time_zone_offset_with_dst)
{
test_offset("America/New_York"sv, 1642558528, offset(-1, 5, 00, 00)); // Wednesday, January 19, 2022 2:15:28 AM
test_offset("America/New_York"sv, 1663553728, offset(-1, 4, 00, 00)); // Monday, September 19, 2022 2:15:28 AM
test_offset("America/New_York"sv, 1671453238, offset(-1, 5, 00, 00)); // Monday, December 19, 2022 12:33:58 PM
test_offset("America/New_York"sv, 1642558528, offset(-1, 5, 00, 00), No); // Wednesday, January 19, 2022 2:15:28 AM
test_offset("America/New_York"sv, 1663553728, offset(-1, 4, 00, 00), Yes); // Monday, September 19, 2022 2:15:28 AM
test_offset("America/New_York"sv, 1671453238, offset(-1, 5, 00, 00), No); // Monday, December 19, 2022 12:33:58 PM
// Phoenix does not observe DST.
test_offset("America/Phoenix"sv, 1642558528, offset(-1, 7, 00, 00)); // Wednesday, January 19, 2022 2:15:28 AM
test_offset("America/Phoenix"sv, 1663553728, offset(-1, 7, 00, 00)); // Monday, September 19, 2022 2:15:28 AM
test_offset("America/Phoenix"sv, 1671453238, offset(-1, 7, 00, 00)); // Monday, December 19, 2022 12:33:58 PM
test_offset("America/Phoenix"sv, 1642558528, offset(-1, 7, 00, 00), No); // Wednesday, January 19, 2022 2:15:28 AM
test_offset("America/Phoenix"sv, 1663553728, offset(-1, 7, 00, 00), No); // Monday, September 19, 2022 2:15:28 AM
test_offset("America/Phoenix"sv, 1671453238, offset(-1, 7, 00, 00), No); // Monday, December 19, 2022 12:33:58 PM
// Moscow's observed DST changed several times in 1919.
test_offset("Europe/Moscow"sv, -1609459200, offset(+1, 2, 31, 19)); // Wednesday, January 1, 1919 12:00:00 AM
test_offset("Europe/Moscow"sv, -1596412800, offset(+1, 4, 31, 19)); // Sunday, June 1, 1919 12:00:00 AM
test_offset("Europe/Moscow"sv, -1592611200, offset(+1, 4, 00, 00)); // Tuesday, July 15, 1919 12:00:00 AM
test_offset("Europe/Moscow"sv, -1589068800, offset(+1, 3, 00, 00)); // Monday, August 25, 1919 12:00:00 AM
test_offset("Europe/Moscow"sv, -1609459200, offset(+1, 2, 31, 19), No); // Wednesday, January 1, 1919 12:00:00 AM
test_offset("Europe/Moscow"sv, -1596412800, offset(+1, 4, 31, 19), Yes); // Sunday, June 1, 1919 12:00:00 AM
test_offset("Europe/Moscow"sv, -1592611200, offset(+1, 4, 00, 00), Yes); // Tuesday, July 15, 1919 12:00:00 AM
test_offset("Europe/Moscow"sv, -1589068800, offset(+1, 3, 00, 00), No); // Monday, August 25, 1919 12:00:00 AM
}
#else
@ -159,7 +162,7 @@ TEST_CASE(time_zone_from_string)
TEST_CASE(get_time_zone_offset)
{
EXPECT_EQ(TimeZone::get_time_zone_offset("UTC", AK::Time::from_seconds(123456)), 0);
EXPECT_EQ(TimeZone::get_time_zone_offset("UTC", AK::Time::from_seconds(123456)), { 0, No });
EXPECT(!TimeZone::get_time_zone_offset("Europe/Paris"sv, {}).has_value());
EXPECT(!TimeZone::get_time_zone_offset("Etc/UTC"sv, {}).has_value());

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@ -286,7 +286,8 @@ double local_tza(double time, [[maybe_unused]] bool is_utc, Optional<StringView>
auto time_since_epoch = Value(time).is_finite_number() ? AK::Time::from_milliseconds(time) : AK::Time::max();
auto maybe_offset = TimeZone::get_time_zone_offset(time_zone, time_since_epoch);
return maybe_offset.value_or(0) * 1000;
return maybe_offset.has_value() ? static_cast<double>(maybe_offset->seconds) * 1000 : 0;
}
// 21.4.1.8 LocalTime ( t ), https://tc39.es/ecma262/#sec-localtime

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@ -175,10 +175,10 @@ i64 get_iana_time_zone_offset_nanoseconds(BigInt const& epoch_nanoseconds, Strin
else
time = Time::from_seconds(*seconds.to_base(10).to_int<i64>());
auto offset_seconds = ::TimeZone::get_time_zone_offset(*time_zone, time);
VERIFY(offset_seconds.has_value());
auto offset = ::TimeZone::get_time_zone_offset(*time_zone, time);
VERIFY(offset.has_value());
return *offset_seconds * 1'000'000'000;
return offset->seconds * 1'000'000'000;
}
// 11.6.5 GetIANATimeZoneNextTransition ( epochNanoseconds, timeZoneIdentifier ), https://tc39.es/proposal-temporal/#sec-temporal-getianatimezonenexttransition

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@ -66,17 +66,17 @@ Optional<StringView> canonicalize_time_zone(StringView time_zone)
Optional<DaylightSavingsRule> __attribute__((weak)) daylight_savings_rule_from_string(StringView) { return {}; }
StringView __attribute__((weak)) daylight_savings_rule_to_string(DaylightSavingsRule) { return {}; }
Optional<i64> __attribute__((weak)) get_time_zone_offset([[maybe_unused]] TimeZone time_zone, AK::Time)
Optional<Offset> __attribute__((weak)) get_time_zone_offset([[maybe_unused]] TimeZone time_zone, AK::Time)
{
#if !ENABLE_TIME_ZONE_DATA
VERIFY(time_zone == TimeZone::UTC);
return 0;
return Offset {};
#else
return {};
#endif
}
Optional<i64> get_time_zone_offset(StringView time_zone, AK::Time time)
Optional<Offset> get_time_zone_offset(StringView time_zone, AK::Time time)
{
if (auto maybe_time_zone = time_zone_from_string(time_zone); maybe_time_zone.has_value())
return get_time_zone_offset(*maybe_time_zone, time);

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@ -14,6 +14,16 @@
namespace TimeZone {
enum class InDST {
No,
Yes,
};
struct Offset {
i64 seconds { 0 };
InDST in_dst { InDST::No };
};
StringView current_time_zone();
Optional<TimeZone> time_zone_from_string(StringView time_zone);
@ -23,7 +33,7 @@ Optional<StringView> canonicalize_time_zone(StringView time_zone);
Optional<DaylightSavingsRule> daylight_savings_rule_from_string(StringView daylight_savings_rule);
StringView daylight_savings_rule_to_string(DaylightSavingsRule daylight_savings_rule);
Optional<i64> get_time_zone_offset(TimeZone time_zone, AK::Time time);
Optional<i64> get_time_zone_offset(StringView time_zone, AK::Time time);
Optional<Offset> get_time_zone_offset(TimeZone time_zone, AK::Time time);
Optional<Offset> get_time_zone_offset(StringView time_zone, AK::Time time);
}

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@ -208,21 +208,21 @@ static Optional<String> format_time_zone_offset(StringView locale, StringView ti
if (!number_system.has_value())
return {};
auto offset_seconds = TimeZone::get_time_zone_offset(time_zone, time);
if (!offset_seconds.has_value())
auto offset = TimeZone::get_time_zone_offset(time_zone, time);
if (!offset.has_value())
return {};
if (*offset_seconds == 0)
if (offset->seconds == 0)
return formats->gmt_zero_format;
auto sign = *offset_seconds > 0 ? formats->symbol_ahead_sign : formats->symbol_behind_sign;
auto separator = *offset_seconds > 0 ? formats->symbol_ahead_separator : formats->symbol_behind_separator;
*offset_seconds = llabs(*offset_seconds);
auto sign = offset->seconds > 0 ? formats->symbol_ahead_sign : formats->symbol_behind_sign;
auto separator = offset->seconds > 0 ? formats->symbol_ahead_separator : formats->symbol_behind_separator;
offset->seconds = llabs(offset->seconds);
auto offset_hours = *offset_seconds / 3'600;
*offset_seconds %= 3'600;
auto offset_hours = offset->seconds / 3'600;
offset->seconds %= 3'600;
auto offset_minutes = *offset_seconds / 60;
*offset_seconds %= 60;
auto offset_minutes = offset->seconds / 60;
offset->seconds %= 60;
StringBuilder builder;
builder.append(sign);
@ -231,8 +231,8 @@ static Optional<String> format_time_zone_offset(StringView locale, StringView ti
// The long format always uses 2-digit hours field and minutes field, with optional 2-digit seconds field.
case CalendarPatternStyle::LongOffset:
builder.appendff("{:02}{}{:02}", offset_hours, separator, offset_minutes);
if (*offset_seconds > 0)
builder.appendff("{}{:02}", separator, *offset_seconds);
if (offset->seconds > 0)
builder.appendff("{}{:02}", separator, offset->seconds);
break;
// The short format is intended for the shortest representation and uses hour fields without leading zero, with optional 2-digit minutes and seconds fields.
@ -240,8 +240,8 @@ static Optional<String> format_time_zone_offset(StringView locale, StringView ti
builder.appendff("{}", offset_hours);
if (offset_minutes > 0) {
builder.appendff("{}{:02}", separator, offset_minutes);
if (*offset_seconds > 0)
builder.appendff("{}{:02}", separator, *offset_seconds);
if (offset->seconds > 0)
builder.appendff("{}{:02}", separator, offset->seconds);
}
break;
@ -250,8 +250,8 @@ static Optional<String> format_time_zone_offset(StringView locale, StringView ti
}
// The digits used for hours, minutes and seconds fields in this format are the locale's default decimal digits.
auto offset = replace_digits_for_number_system(*number_system, builder.build());
return formats->gmt_format.replace("{0}"sv, offset);
auto result = replace_digits_for_number_system(*number_system, builder.build());
return formats->gmt_format.replace("{0}"sv, result);
}
// https://unicode.org/reports/tr35/tr35-dates.html#Time_Zone_Format_Terminology