cache icu formatter and calendar for each locale

libgnucash/engine/gnc-datetime.cpp

@@ -541,54 +541,62 @@ GncDateTimeImpl::timestamp()
  return str.substr(0, 8) + str.substr(9, 15);
 }
 
+using DateFormatPtr = std::shared_ptr<icu::DateFormat>;
+using CalendarPtr = std::shared_ptr<icu::Calendar>;
+
+static std::tuple<DateFormatPtr, CalendarPtr>
+locale_to_formatter_and_calendar (const std::string locale_str)
+{
+ static std::map<std::string, std::optional<std::tuple<DateFormatPtr, CalendarPtr>>> cache;
+ auto& tuple = cache[locale_str];
+ if (!tuple)
+ {
+ auto locale = icu::Locale::createCanonical (locale_str.c_str());
+ std::shared_ptr<icu::DateFormat> formatter(icu::DateFormat::createDateInstance(icu::DateFormat::kDefault, locale));
+ if (formatter == nullptr)
+ throw std::invalid_argument ("Cannot parse string");
+
+ UErrorCode status = U_ZERO_ERROR;
+ std::shared_ptr<icu::Calendar> calendar(icu::Calendar::createInstance(locale, status));
+ if (U_FAILURE(status))
+ throw std::invalid_argument ("Cannot parse string");
+
+ tuple = std::make_tuple<DateFormatPtr, CalendarPtr>(std::move(formatter), std::move(calendar));
+ }
+
+ return *tuple;
+}
+
 /* Member function definitions for GncDateImpl.
  */
 GncDateImpl::GncDateImpl(const std::string str, const std::string locale_str) :
  /* Temporarily initialized to today, will be used and adjusted in the code below */
  m_greg(boost::gregorian::day_clock::local_day())
 {
- UErrorCode status = U_ZERO_ERROR;
-
  std::cout << locale_str << '|' << str << ": ";
 
- icu::Locale locale = icu::Locale::createCanonical (locale_str.c_str());
- std::unique_ptr<icu::DateFormat> formatter(icu::DateFormat::createDateInstance(icu::DateFormat::kDefault, locale));
- if (formatter == nullptr)
- throw std::invalid_argument ("Cannot parse string");
-
+ auto [formatter, calendar] = locale_to_formatter_and_calendar (locale_str);
  icu::UnicodeString input = icu::UnicodeString::fromUTF8(str);
  icu::ParsePosition parsePos;
 
  UDate date = formatter->parse(input, parsePos);
  if (parsePos.getErrorIndex() != -1)
  {
- std::cout << "1\n";
- throw std::invalid_argument ("Cannot parse string");
- }
-
- std::unique_ptr<icu::Calendar> calendar(icu::Calendar::createInstance(locale, status));
- if (U_FAILURE(status))
- {
- std::cout << "2\n";
+ std::cout << "cannot parse " << std::endl;
  throw std::invalid_argument ("Cannot parse string");
  }
 
+ UErrorCode status = U_ZERO_ERROR;
  calendar->setTime(date, status);
  if (U_FAILURE(status))
- {
- std::cout << "3\n";
  throw std::invalid_argument ("Cannot parse string");
- }
 
  int32_t day = calendar->get(UCAL_DATE, status);
  int32_t month = calendar->get(UCAL_MONTH, status) + 1;
  int32_t year = calendar->get(UCAL_YEAR, status);
 
  if (U_FAILURE(status))
- {
- std::cout << "4\n";
  throw std::invalid_argument ("Cannot parse string");
- }
 
  std::cout << day << '/' << month << '/' << year << std::endl;
  m_greg = Date(year, month, day);