diff options
3 files changed, 90 insertions, 16 deletions
diff --git a/Meta/Lagom/Tools/CodeGenerators/LibTimeZone/GenerateTimeZoneData.cpp b/Meta/Lagom/Tools/CodeGenerators/LibTimeZone/GenerateTimeZoneData.cpp index 46efbe016a..64e05485d3 100644 --- a/Meta/Lagom/Tools/CodeGenerators/LibTimeZone/GenerateTimeZoneData.cpp +++ b/Meta/Lagom/Tools/CodeGenerators/LibTimeZone/GenerateTimeZoneData.cpp @@ -450,9 +450,55 @@ 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) +{ + auto const& dst_rules = s_dst_offsets[time_zone_offset.dst_rule]; + + DaylightSavingsOffset const* standard_offset = nullptr; + DaylightSavingsOffset const* daylight_offset = nullptr; + + auto time_in_effect_for_rule = [&](auto const& dst_rule) { + auto in_effect = dst_rule.in_effect; + in_effect.year = seconds_since_epoch_to_year(time.to_seconds()); + + return in_effect.time_since_epoch(); + }; + + auto preferred_rule = [&](auto* current_offset, auto& new_offset) { + if (!current_offset) + return &new_offset; + + auto new_time_in_effect = time_in_effect_for_rule(new_offset); + return (time >= new_time_in_effect) ? &new_offset : current_offset; + }; + + for (size_t index = 0; (index < dst_rules.size()) && (!standard_offset || !daylight_offset); ++index) { + auto const& dst_rule = dst_rules[index]; + + auto year_from = AK::Time::from_timestamp(dst_rule.year_from, 1, 1, 0, 0, 0, 0); + auto year_to = AK::Time::from_timestamp(dst_rule.year_to + 1, 1, 1, 0, 0, 0, 0); + if ((time < year_from) || (time >= year_to)) + continue; + + if (dst_rule.offset == 0) + standard_offset = preferred_rule(standard_offset, dst_rule); + else + daylight_offset = preferred_rule(daylight_offset, dst_rule); + } + + if (!standard_offset || !daylight_offset) + return 0; + + 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; +} + Optional<i64> get_time_zone_offset(TimeZone time_zone, AK::Time time) { - // FIXME: This implementation completely ignores DST. auto const& time_zone_offsets = s_time_zone_offsets[to_underlying(time_zone)]; size_t index = 0; @@ -464,7 +510,15 @@ Optional<i64> get_time_zone_offset(TimeZone time_zone, AK::Time time) } VERIFY(index < time_zone_offsets.size()); - return time_zone_offsets[index].offset; + auto const& time_zone_offset = time_zone_offsets[index]; + + i64 dst_offset = 0; + if (time_zone_offset.dst_rule != -1) + dst_offset = get_dst_offset(time_zone_offset, time); + else + dst_offset = time_zone_offset.dst_offset; + + return time_zone_offset.offset + dst_offset; } } diff --git a/Tests/LibTimeZone/TestTimeZone.cpp b/Tests/LibTimeZone/TestTimeZone.cpp index 50efd28a25..19cfa5fc42 100644 --- a/Tests/LibTimeZone/TestTimeZone.cpp +++ b/Tests/LibTimeZone/TestTimeZone.cpp @@ -85,18 +85,20 @@ TEST_CASE(canonicalize_time_zone) EXPECT(!TimeZone::canonicalize_time_zone("I don't exist"sv).has_value()); } -TEST_CASE(get_time_zone_offset) +static i64 offset(i64 sign, i64 hours, i64 minutes, i64 seconds) { - auto offset = [](i64 sign, i64 hours, i64 minutes, i64 seconds) { - return sign * ((hours * 3600) + (minutes * 60) + seconds); - }; + return sign * ((hours * 3600) + (minutes * 60) + seconds); +} - auto test_offset = [](auto time_zone, i64 time, i64 expected_offset) { - 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); - }; +static void test_offset(StringView time_zone, i64 time, i64 expected_offset) +{ + 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); +} +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 @@ -126,6 +128,24 @@ TEST_CASE(get_time_zone_offset) 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 + + // 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 + + // 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 +} + #else TEST_CASE(time_zone_from_string) diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/TimeZone/TimeZone.prototype.getOffsetStringFor.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/TimeZone/TimeZone.prototype.getOffsetStringFor.js index 5c926b3133..0458c71fcc 100644 --- a/Userland/Libraries/LibJS/Tests/builtins/Temporal/TimeZone/TimeZone.prototype.getOffsetStringFor.js +++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/TimeZone/TimeZone.prototype.getOffsetStringFor.js @@ -9,15 +9,15 @@ describe("correct behavior", () => { ["GMT", "+00:00"], ["Etc/GMT+12", "-12:00"], ["Etc/GMT-12", "+12:00"], - ["Europe/London", "+00:00"], - ["Europe/Berlin", "+01:00"], - ["America/New_York", "-05:00"], - ["America/Los_Angeles", "-08:00"], + ["Europe/London", "+01:00"], + ["Europe/Berlin", "+02:00"], + ["America/New_York", "-04:00"], + ["America/Los_Angeles", "-07:00"], ["+00:00", "+00:00"], ["+01:30", "+01:30"], ]; for (const [arg, expected] of values) { - const instant = new Temporal.Instant(1600000000000000000n); + const instant = new Temporal.Instant(1600000000000000000n); // Sunday, September 13, 2020 12:26:40 PM expect(new Temporal.TimeZone(arg).getOffsetStringFor(instant)).toBe(expected); } }); |