mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-10-20 15:30:50 +00:00
e1bb33cad0
* add forgotten const * print exception string if switching to server timezone failed * protocol compatibility with old versions * use ALWAYS_INLINE in DateLUT.h
82 lines
2.4 KiB
C++
82 lines
2.4 KiB
C++
#pragma once
|
|
|
|
#include <common/DateLUTImpl.h>
|
|
#include <common/singleton.h>
|
|
#include <DB/Core/Defines.h>
|
|
#include <Poco/Exception.h>
|
|
|
|
#include <unordered_map>
|
|
#include <vector>
|
|
#include <atomic>
|
|
#include <mutex>
|
|
#include <memory>
|
|
|
|
/// This class provides lazy initialization and lookup of singleton DateLUTImpl objects for a given timezone.
|
|
class DateLUT : public Singleton<DateLUT>
|
|
{
|
|
friend class Singleton<DateLUT>;
|
|
|
|
public:
|
|
DateLUT(const DateLUT &) = delete;
|
|
DateLUT & operator=(const DateLUT &) = delete;
|
|
|
|
/// Return singleton DateLUTImpl instance for the default time zone.
|
|
static ALWAYS_INLINE const DateLUTImpl & instance()
|
|
{
|
|
const auto & date_lut = Singleton<DateLUT>::instance();
|
|
return *date_lut.default_impl.load(std::memory_order_acquire);
|
|
}
|
|
|
|
/// Return singleton DateLUTImpl instance for a given time zone.
|
|
static ALWAYS_INLINE const DateLUTImpl & instance(const std::string & time_zone)
|
|
{
|
|
const auto & date_lut = Singleton<DateLUT>::instance();
|
|
if (time_zone.empty())
|
|
return *date_lut.default_impl.load(std::memory_order_acquire);
|
|
|
|
return date_lut.getImplementation(time_zone);
|
|
}
|
|
|
|
static void setDefaultTimezone(const std::string & time_zone)
|
|
{
|
|
auto & date_lut = Singleton<DateLUT>::instance();
|
|
const auto & impl = date_lut.getImplementation(time_zone);
|
|
date_lut.default_impl.store(&impl, std::memory_order_release);
|
|
}
|
|
|
|
protected:
|
|
DateLUT();
|
|
|
|
private:
|
|
ALWAYS_INLINE const DateLUTImpl & getImplementation(const std::string & time_zone) const
|
|
{
|
|
auto it = time_zone_to_group.find(time_zone);
|
|
if (it == time_zone_to_group.end())
|
|
throw Poco::Exception("Invalid time zone " + time_zone);
|
|
size_t group_id = it->second;
|
|
|
|
auto initialize_impl = [this, group_id, &time_zone]()
|
|
{
|
|
date_lut_impls[group_id] = std::make_unique<DateLUTImpl>(time_zone);
|
|
};
|
|
|
|
std::call_once(initialized_flags[group_id], initialize_impl);
|
|
return *date_lut_impls[group_id];
|
|
}
|
|
|
|
private:
|
|
/// A mapping of a time zone name into a group id of equivalent time zones.
|
|
/// Two time zones are considered equivalent if they have the same properties.
|
|
using TimeZoneToGroup = std::unordered_map<std::string, size_t>;
|
|
|
|
TimeZoneToGroup time_zone_to_group;
|
|
|
|
using DateLUTImplPtr = std::unique_ptr<DateLUTImpl>;
|
|
|
|
/// A vector of lookup tables indexed by group id and their initialization flags.
|
|
mutable std::vector<DateLUTImplPtr> date_lut_impls;
|
|
mutable std::vector<std::once_flag> initialized_flags;
|
|
|
|
std::atomic<const DateLUTImpl *> default_impl;
|
|
};
|