Method getSystemTimeZone

src/common/TimeZoneUtil.cpp:323–435

Return the current user's time zone.

// Return the current user's time zone.
USHORT TimeZoneUtil::getSystemTimeZone()
{
	static volatile bool cachedError = false;
	static volatile USHORT cachedTimeZoneId = TimeZoneUtil::GMT_ZONE;
	static volatile int32_t cachedTimeZoneNameLen = -1;
	static char cachedTimeZoneName[TimeZoneUtil::MAX_SIZE];
	static GlobalPtr<RWLock> lock;

	if (cachedError)
		return cachedTimeZoneId;

	// ASF: The code below in this function is prepared to detect changes in OS time zone or config setting, but
	// the called functions are not. So cache and return directly the previously detected time zone.
	if (cachedTimeZoneNameLen != -1)
		return cachedTimeZoneId;

	UErrorCode icuErrorCode = U_ZERO_ERROR;
	Jrd::UnicodeUtil::ConversionICU& icuLib = Jrd::UnicodeUtil::getConversionICU();

	char buffer[TimeZoneUtil::MAX_SIZE];
	const char* str = buffer;
	int32_t len;
	const char* configDefault = Config::getDefaultTimeZone();
	bool strictParse = true;

	if (configDefault && configDefault[0])
	{
		str = configDefault;
		len = strlen(str);
	}
	else
	{
		UChar unicodeBuffer[TimeZoneUtil::MAX_LEN];
		len = icuLib.ucalGetDefaultTimeZone(unicodeBuffer, FB_NELEM(unicodeBuffer), &icuErrorCode);

		if (!U_FAILURE(icuErrorCode))
		{
			UChar* src = unicodeBuffer;
			char* dst = buffer;

			while (src - unicodeBuffer < len)
				*dst++ = (char) *src++;

			str = buffer;
			buffer[len] = '\0';

			strictParse = false;
		}
		else
		{
			gds__log("ICU error (%d) retrieving the system time zone. Falling back to displacement.",
				int(icuErrorCode));
		}
	}

	ReadLockGuard readGuard(lock, "TimeZoneUtil::getSystemTimeZone");

	if (!U_FAILURE(icuErrorCode) &&