intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 118 insertions, 0 deletions

diff --git a/library/cpp/yt/string/enum-inl.h b/library/cpp/yt/string/enum-inl.h
new file mode 100644
index 0000000000..ab8acff71b
--- /dev/null
+++ b/library/cpp/yt/string/enum-inl.h
@@ -0,0 +1,118 @@
+#ifndef ENUM_INL_H_
+#error "Direct inclusion of this file is not allowed, include enum.h"
+// For the sake of sane code completion.
+#include "enum.h"
+#endif
+
+#include <util/string/printf.h>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+namespace NDetail {
+
+[[noreturn]]
+void ThrowMalformedEnumValueException(
+    TStringBuf typeName,
+    TStringBuf value);
+
+void FormatUnknownEnumValue(
+    TStringBuilderBase* builder,
+    TStringBuf name,
+    i64 value);
+
+} // namespace NDetail
+
+template <class T>
+std::optional<T> TryParseEnum(TStringBuf value)
+{
+    static_assert(TEnumTraits<T>::IsEnum);
+
+    auto tryFromString = [] (TStringBuf value) -> std::optional<T> {
+        T result;
+        if (auto ok = TEnumTraits<T>::FindValueByLiteral(DecodeEnumValue(value), &result)) {
+            return result;
+        }
+        return {};
+    };
+
+    if constexpr (TEnumTraits<T>::IsBitEnum) {
+        T result{};
+        TStringBuf token;
+        while (value.NextTok('|', token)) {
+            if (auto scalar = tryFromString(StripString(token))) {
+                result |= *scalar;
+            } else {
+                return {};
+            }
+        }
+        return result;
+    } else {
+        return tryFromString(value);
+    }
+}
+
+template <class T>
+T ParseEnum(TStringBuf value)
+{
+    if (auto optionalResult = TryParseEnum<T>(value)) {
+        return *optionalResult;
+    }
+    NDetail::ThrowMalformedEnumValueException(TEnumTraits<T>::GetTypeName(), value);
+}
+
+template <class T>
+void FormatEnum(TStringBuilderBase* builder, T value, bool lowerCase)
+{
+    static_assert(TEnumTraits<T>::IsEnum);
+
+    auto formatScalarValue = [builder, lowerCase] (T value) {
+        auto* literal = TEnumTraits<T>::FindLiteralByValue(value);
+        if (!literal) {
+            YT_VERIFY(!TEnumTraits<T>::IsBitEnum);
+            NDetail::FormatUnknownEnumValue(
+                builder,
+                TEnumTraits<T>::GetTypeName(),
+                static_cast<typename TEnumTraits<T>::TUnderlying>(value));
+            return;
+        }
+
+        if (lowerCase) {
+            CamelCaseToUnderscoreCase(builder, *literal);
+        } else {
+            builder->AppendString(*literal);
+        }
+    };
+
+    if constexpr (TEnumTraits<T>::IsBitEnum) {
+        if (auto* literal = TEnumTraits<T>::FindLiteralByValue(value)) {
+            formatScalarValue(value);
+            return;
+        }
+        auto first = true;
+        for (auto scalarValue : TEnumTraits<T>::GetDomainValues()) {
+            if (Any(value & scalarValue)) {
+                if (!first) {
+                    builder->AppendString(TStringBuf(" | "));
+                }
+                first = false;
+                formatScalarValue(scalarValue);
+            }
+        }
+    } else {
+        formatScalarValue(value);
+    }
+}
+
+template <class T>
+TString FormatEnum(T value, typename TEnumTraits<T>::TType*)
+{
+    TStringBuilder builder;
+    FormatEnum(&builder, value, /*lowerCase*/ true);
+    return builder.Flush();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT