Method ThreadOnce

Core/ThreadLock_Win32.cpp:53–81

}

void ThreadLock::ThreadOnce(ThreadOnceToken_t *onceToken, void (*callback)()) {
    if (!onceToken || !callback) {
        assert(onceToken);
        assert(callback);
        return;
    }
    while (true) {
        auto expected = ThreadOnceUninitialized;
        atomic_compare_exchange_weak(onceToken, &expected, ThreadOnceInitializing);
        switch (expected) {
            case ThreadOnceInitialized:
                return;
            case ThreadOnceUninitialized:
                callback();
                onceToken->store(ThreadOnceInitialized);
                return;
            case ThreadOnceInitializing: {
                // another thread is initializing, let's wait for 1ms
                ThreadLock::Sleep(1);
                break;
            }
            default: {
                MMKVError("should never happen:%d", expected);
                assert(0);
                return;
            }
        }
    }
}

void ThreadLock::Sleep(int ms) {
    ::Sleep(ms);