intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 41 insertions, 0 deletions

diff --git a/util/thread/singleton.h b/util/thread/singleton.h
new file mode 100644
index 0000000000..4a1e05aea0
--- /dev/null
+++ b/util/thread/singleton.h
@@ -0,0 +1,41 @@
+#pragma once
+
+#include <util/system/tls.h>
+#include <util/generic/singleton.h>
+#include <util/generic/ptr.h>
+
+namespace NPrivate {
+    template <class T, size_t Priority>
+    struct TFastThreadSingletonHelper {
+        static inline T* GetSlow() {
+            return SingletonWithPriority<NTls::TValue<T>, Priority>()->GetPtr();
+        }
+
+        static inline T* Get() {
+#if defined(Y_HAVE_FAST_POD_TLS)
+            Y_POD_STATIC_THREAD(T*) fast(nullptr);
+
+            if (Y_UNLIKELY(!fast)) {
+                fast = GetSlow();
+            }
+
+            return fast;
+#else
+            return GetSlow();
+#endif
+        }
+    };
+}
+
+template <class T, size_t Priority>
+static inline T* FastTlsSingletonWithPriority() {
+    return ::NPrivate::TFastThreadSingletonHelper<T, Priority>::Get();
+}
+
+// NB: the singleton is the same for all modules that use
+// FastTlsSingleton with the same type parameter. If unique singleton
+// required, use unique types.
+template <class T>
+static inline T* FastTlsSingleton() {
+    return FastTlsSingletonWithPriority<T, TSingletonTraits<T>::Priority>();
+}