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#include "singleton.h"
#include <util/system/spinlock.h>
#include <util/system/thread.h>
#include <util/system/sanitizers.h>
#include <cstring>
namespace {
static inline bool MyAtomicTryLock(std::atomic<size_t>& a, size_t v) noexcept {
size_t zero = 0;
return a.compare_exchange_strong(zero, v);
}
static inline bool MyAtomicTryAndTryLock(std::atomic<size_t>& a, size_t v) noexcept {
return a.load(std::memory_order_acquire) == 0 && MyAtomicTryLock(a, v);
}
static inline size_t MyThreadId() noexcept {
const size_t ret = TThread::CurrentThreadId();
if (ret) {
return ret;
}
//clash almost impossible, ONLY if we have threads with ids 0 and 1!
return 1;
}
}
void NPrivate::FillWithTrash(void* ptr, size_t len) {
#if defined(NDEBUG)
Y_UNUSED(ptr);
Y_UNUSED(len);
#else
if constexpr (NSan::TSanIsOn()) {
Y_UNUSED(ptr);
Y_UNUSED(len);
} else {
memset(ptr, 0xBA, len);
}
#endif
}
void NPrivate::LockRecursive(std::atomic<size_t>& lock) noexcept {
const size_t id = MyThreadId();
Y_ABORT_UNLESS(lock.load(std::memory_order_acquire) != id, "recursive singleton initialization");
if (!MyAtomicTryLock(lock, id)) {
TSpinWait sw;
do {
sw.Sleep();
} while (!MyAtomicTryAndTryLock(lock, id));
}
}
void NPrivate::UnlockRecursive(std::atomic<size_t>& lock) noexcept {
Y_ABORT_UNLESS(lock.load(std::memory_order_acquire) == MyThreadId(), "unlock from another thread?!?!");
lock.store(0);
}
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