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Merge pull request #11069 from lat9nq/mingw-no-tzdb

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common: Use arithmetic instead of string ops to get time zone
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liamwhite 2023-07-21 15:05:59 -04:00 committed by GitHub
commit 8927f016e1
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2 changed files with 21 additions and 29 deletions
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3
src/common/settings.cpp
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@ -26,7 +26,8 @@ std::string GetTimeZoneString() {
std::string location_name;
if (time_zone_index == 0) { // Auto
#if __cpp_lib_chrono >= 201907L
#if __cpp_lib_chrono >= 201907L && !defined(MINGW)
// Disabled for MinGW -- tzdb always returns Etc/UTC
try {
const struct std::chrono::tzdb& time_zone_data = std::chrono::get_tzdb();
const std::chrono::time_zone* current_zone = time_zone_data.current_zone();

47
src/common/time_zone.cpp
View file

@ -4,13 +4,13 @@
#include <chrono>
#include <exception>
#include <iomanip>
#include <map>
#include <sstream>
#include <stdexcept>
#include <fmt/chrono.h>
#include <fmt/core.h>
#include "common/logging/log.h"
#include "common/settings.h"
#include "common/time_zone.h"
namespace Common::TimeZone {
@ -33,32 +33,29 @@ std::string GetDefaultTimeZone() {
return "GMT";
}
static std::string GetOsTimeZoneOffset() {
const std::time_t t{std::time(nullptr)};
const std::tm tm{*std::localtime(&t)};
return fmt::format("{:%z}", tm);
}
static int ConvertOsTimeZoneOffsetToInt(const std::string& timezone) {
try {
return std::stoi(timezone);
} catch (const std::invalid_argument&) {
LOG_CRITICAL(Common, "invalid_argument with {}!", timezone);
return 0;
} catch (const std::out_of_range&) {
LOG_CRITICAL(Common, "out_of_range with {}!", timezone);
return 0;
}
// Results are not comparable to seconds since Epoch
static std::time_t TmSpecToSeconds(const struct std::tm& spec) {
const int year = spec.tm_year - 1; // Years up to now
const int leap_years = year / 4 - year / 100;
std::time_t cumulative = spec.tm_year;
cumulative = cumulative * 365 + leap_years + spec.tm_yday; // Years to days
cumulative = cumulative * 24 + spec.tm_hour; // Days to hours
cumulative = cumulative * 60 + spec.tm_min; // Hours to minutes
cumulative = cumulative * 60 + spec.tm_sec; // Minutes to seconds
return cumulative;
}
std::chrono::seconds GetCurrentOffsetSeconds() {
const int offset{ConvertOsTimeZoneOffsetToInt(GetOsTimeZoneOffset())};
const std::time_t t{std::time(nullptr)};
const std::tm local{*std::localtime(&t)};
const std::tm gmt{*std::gmtime(&t)};
int seconds{(offset / 100) * 60 * 60}; // Convert hour component to seconds
seconds += (offset % 100) * 60; // Convert minute component to seconds
// gmt_seconds is a different offset than time(nullptr)
const auto gmt_seconds = TmSpecToSeconds(gmt);
const auto local_seconds = TmSpecToSeconds(local);
const auto seconds_offset = local_seconds - gmt_seconds;
return std::chrono::seconds{seconds};
return std::chrono::seconds{seconds_offset};
}
// Key is [Hours * 100 + Minutes], multiplied by 100 if DST
@ -71,11 +68,6 @@ const static std::map<s64, const char*> off_timezones = {
};
std::string FindSystemTimeZone() {
#if defined(MINGW)
// MinGW has broken strftime -- https://sourceforge.net/p/mingw-w64/bugs/793/
// e.g. fmt::format("{:%z}") -- returns "Eastern Daylight Time" when it should be "-0400"
return timezones[0];
#else
const s64 seconds = static_cast<s64>(GetCurrentOffsetSeconds().count());
const s64 minutes = seconds / 60;
@ -97,7 +89,6 @@ std::string FindSystemTimeZone() {
}
}
return fmt::format("Etc/GMT{:s}{:d}", hours > 0 ? "-" : "+", std::abs(hours));
#endif
}
} // namespace Common::TimeZone