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//
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// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
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// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
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//
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef MOZC_BASE_SINGLETON_H_
#define MOZC_BASE_SINGLETON_H_
#include "base/mutex.h"
namespace mozc {
class SingletonFinalizer {
public:
typedef void (*FinalizerFunc)();
// Do not call this method directly.
// use Singleton<Typename> instead.
static void AddFinalizer(FinalizerFunc func);
// Call Finalize() if you want to finalize
// all instances created by Sigleton.
//
// Mozc UI for Windows (DLL) can call
// SigletonFinalizer::Finalize()
// at an appropriate timing.
static void Finalize();
};
// Thread-safe Singleton class.
// Usage:
//
// class Foo {}
//
// Foo *instance = mozc::Singleton<Foo>::get();
template <typename T>
class Singleton {
public:
static T *get() {
CallOnce(&once_, &Singleton<T>::Init);
return instance_;
}
private:
static void Init() {
SingletonFinalizer::AddFinalizer(&Singleton<T>::Delete);
instance_ = new T;
}
static void Delete() {
delete instance_;
instance_ = nullptr;
ResetOnce(&once_);
}
static once_t once_;
static T *instance_;
};
template <typename T>
once_t Singleton<T>::once_ = MOZC_ONCE_INIT;
template <typename T>
T *Singleton<T>::instance_ = nullptr;
// SingletonMockable class.
// Usage: (quote from clock.cc)
//
// using ClockSingleton = SingletonMockable<ClockInterface, ClockImpl>;
//
// uint64 Clock::GetTime() {
// return ClockSingleton::Get()->GetTime();
// }
//
// void Clock::SetClockForUnitTest(ClockInterface *clock_mock) {
// ClockSingleton::SetMock(clock_mock);
// }
template <class Interface, class Impl>
class SingletonMockable {
public:
static Interface *Get() {
if (mock_) {
return mock_;
}
static Impl *impl = new Impl();
return impl;
}
static void SetMock(Interface *mock) {
mock_ = mock;
}
private:
static Interface *mock_;
};
template <class Interface, class Impl>
Interface *SingletonMockable<Interface, Impl>::mock_ = nullptr;
} // namespace mozc
#endif // MOZC_BASE_SINGLETON_H_