intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 76 insertions, 0 deletions

diff --git a/library/cpp/scheme/util/scheme_holder.h b/library/cpp/scheme/util/scheme_holder.h
new file mode 100644
index 0000000000..f2fa16d1cd
--- /dev/null
+++ b/library/cpp/scheme/util/scheme_holder.h
@@ -0,0 +1,76 @@
+#pragma once
+
+#include <library/cpp/scheme/scheme.h>
+
+
+// Scheme adapter that holds referenced value
+template <typename TScheme>
+class TSchemeHolder {
+public:
+    TSchemeHolder()
+        : Value_(NSc::Null())
+        , Scheme_(&Value_)
+    {
+    }
+
+    explicit TSchemeHolder(NSc::TValue&& value)
+        : Value_(std::move(value))
+        , Scheme_(&Value_)
+    {
+    }
+
+    explicit TSchemeHolder(const NSc::TValue& value)
+        : Value_(value)
+        , Scheme_(&Value_)
+    {
+    }
+
+    TSchemeHolder(TSchemeHolder<TScheme>&& rhs)
+        : Value_(std::move(rhs.Value_))
+        , Scheme_(&Value_)
+    {
+    }
+
+    TSchemeHolder(const TSchemeHolder<TScheme>& rhs)
+        : Value_(rhs.Value_)
+        , Scheme_(&Value_)
+    {
+    }
+
+    TSchemeHolder<TScheme>& operator=(TSchemeHolder<TScheme>&& rhs) {
+        Value_ = std::move(rhs.Value_);
+        return *this;
+    }
+    TSchemeHolder<TScheme>& operator=(const TSchemeHolder<TScheme>& rhs) {
+        Value_ = rhs.Value_;
+        return *this;
+    }
+
+    TScheme& Scheme() {
+        return Scheme_;
+    }
+    const TScheme& Scheme() const {
+        return Scheme_;
+    }
+    TScheme& operator->() {
+        return Scheme_;
+    }
+    const TScheme& operator->() const {
+        return Scheme_;
+    }
+
+    NSc::TValue& Value() {
+        return Value_;
+    }
+    const NSc::TValue& Value() const {
+        return Value_;
+    }
+
+    bool IsNull() const {
+        return Value_.IsNull();
+    }
+
+private:
+    NSc::TValue Value_;
+    TScheme Scheme_;
+};