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- /*
- * Copyright (c) 2022, Tim Flynn <trflynn89@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
- #include <AK/String.h>
- #include <LibTimeZone/TimeZone.h>
- #include <stdio.h>
- #include <time.h>
- namespace TimeZone {
- // NOTE: Without ENABLE_TIME_ZONE_DATA LibTimeZone operates in a UTC-only mode and only recognizes
- // the 'UTC' time zone, which is slightly more useful than a bunch of dummy functions that
- // can't do anything. When we build with time zone data, these weakly linked functions are
- // replaced with their proper counterparts.
- #if !ENABLE_TIME_ZONE_DATA
- enum class TimeZone : u16 {
- UTC,
- };
- #endif
- class TimeZoneFile {
- public:
- TimeZoneFile(char const* mode)
- : m_file(fopen("/etc/timezone", mode))
- {
- if (m_file)
- flockfile(m_file);
- }
- ~TimeZoneFile()
- {
- if (m_file) {
- funlockfile(m_file);
- fclose(m_file);
- }
- }
- ErrorOr<String> read_time_zone()
- {
- if (!m_file)
- return Error::from_string_literal("Could not open /etc/timezone");
- Array<u8, 128> buffer;
- size_t bytes = fread(buffer.data(), 1, buffer.size(), m_file);
- if (bytes == 0)
- return Error::from_string_literal("Could not read time zone from /etc/timezone");
- return String(buffer.span().slice(0, bytes)).trim_whitespace();
- }
- ErrorOr<void> write_time_zone(StringView time_zone)
- {
- if (!m_file)
- return Error::from_string_literal("Could not open /etc/timezone");
- auto bytes = fwrite(time_zone.characters_without_null_termination(), 1, time_zone.length(), m_file);
- if (bytes != time_zone.length())
- return Error::from_string_literal("Could not write new time zone to /etc/timezone");
- return {};
- }
- private:
- FILE* m_file { nullptr };
- };
- StringView system_time_zone()
- {
- TimeZoneFile time_zone_file("r");
- // FIXME: Propagate the error to existing callers.
- if (auto time_zone = time_zone_file.read_time_zone(); !time_zone.is_error())
- return canonicalize_time_zone(time_zone.value()).value_or("UTC"sv);
- return "UTC"sv;
- }
- StringView current_time_zone()
- {
- return canonicalize_time_zone(tzname[0]).value_or("UTC"sv);
- }
- ErrorOr<void> change_time_zone([[maybe_unused]] StringView time_zone)
- {
- #ifdef __serenity__
- TimeZoneFile time_zone_file("w");
- if (auto new_time_zone = canonicalize_time_zone(time_zone); new_time_zone.has_value())
- return time_zone_file.write_time_zone(*new_time_zone);
- return Error::from_string_literal("Provided time zone is not supported");
- #else
- // Do not even attempt to change the time zone of someone's host machine.
- return {};
- #endif
- }
- Span<StringView const> __attribute__((weak)) all_time_zones()
- {
- #if !ENABLE_TIME_ZONE_DATA
- static constexpr auto utc = Array { "UTC"sv };
- return utc;
- #else
- return {};
- #endif
- }
- Optional<TimeZone> __attribute__((weak)) time_zone_from_string([[maybe_unused]] StringView time_zone)
- {
- #if !ENABLE_TIME_ZONE_DATA
- if (time_zone.equals_ignoring_case("UTC"sv))
- return TimeZone::UTC;
- #endif
- return {};
- }
- StringView __attribute__((weak)) time_zone_to_string([[maybe_unused]] TimeZone time_zone)
- {
- #if !ENABLE_TIME_ZONE_DATA
- VERIFY(time_zone == TimeZone::UTC);
- return "UTC"sv;
- #else
- return {};
- #endif
- }
- Optional<StringView> canonicalize_time_zone(StringView time_zone)
- {
- auto maybe_time_zone = time_zone_from_string(time_zone);
- if (!maybe_time_zone.has_value())
- return {};
- auto canonical_time_zone = time_zone_to_string(*maybe_time_zone);
- if (canonical_time_zone.is_one_of("Etc/UTC"sv, "Etc/GMT"sv))
- return "UTC"sv;
- return canonical_time_zone;
- }
- Optional<DaylightSavingsRule> __attribute__((weak)) daylight_savings_rule_from_string(StringView) { return {}; }
- StringView __attribute__((weak)) daylight_savings_rule_to_string(DaylightSavingsRule) { return {}; }
- 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 Offset {};
- #else
- return {};
- #endif
- }
- 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);
- return {};
- }
- Optional<Array<NamedOffset, 2>> __attribute__((weak)) get_named_time_zone_offsets([[maybe_unused]] TimeZone time_zone, AK::Time)
- {
- #if !ENABLE_TIME_ZONE_DATA
- VERIFY(time_zone == TimeZone::UTC);
- NamedOffset utc_offset {};
- utc_offset.name = "UTC"sv;
- return Array { utc_offset, utc_offset };
- #else
- return {};
- #endif
- }
- Optional<Array<NamedOffset, 2>> get_named_time_zone_offsets(StringView time_zone, AK::Time time)
- {
- if (auto maybe_time_zone = time_zone_from_string(time_zone); maybe_time_zone.has_value())
- return get_named_time_zone_offsets(*maybe_time_zone, time);
- return {};
- }
- Optional<Location> __attribute__((weak)) get_time_zone_location(TimeZone) { return {}; }
- Optional<Location> get_time_zone_location(StringView time_zone)
- {
- if (auto maybe_time_zone = time_zone_from_string(time_zone); maybe_time_zone.has_value())
- return get_time_zone_location(*maybe_time_zone);
- return {};
- }
- }
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