intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 52 insertions, 0 deletions

diff --git a/library/cpp/protobuf/util/path.h b/library/cpp/protobuf/util/path.h
new file mode 100644
index 0000000000..487f643a2d
--- /dev/null
+++ b/library/cpp/protobuf/util/path.h
@@ -0,0 +1,52 @@
+#pragma once
+
+#include <google/protobuf/descriptor.h>
+#include <google/protobuf/message.h>
+
+#include <util/generic/vector.h>
+
+namespace NProtoBuf {
+    class TFieldPath {
+    public:
+        TFieldPath();
+        TFieldPath(const Descriptor* msgType, const TStringBuf& path); // throws exception if path doesn't exist
+        TFieldPath(const TVector<const FieldDescriptor*>& path);
+        TFieldPath(const TFieldPath&) = default;
+        TFieldPath& operator=(const TFieldPath&) = default;
+
+        bool InitUnsafe(const Descriptor* msgType, const TStringBuf path); // noexcept
+        void Init(const Descriptor* msgType, const TStringBuf& path);      // throws
+
+        const TVector<const FieldDescriptor*>& Fields() const {
+            return Path;
+        }
+
+        void AddField(const FieldDescriptor* field) {
+            Path.push_back(field);
+        }
+
+        const Descriptor* ParentType() const {
+            return Empty() ? nullptr : Path.front()->containing_type();
+        }
+
+        const FieldDescriptor* FieldDescr() const {
+            return Empty() ? nullptr : Path.back();
+        }
+
+        bool Empty() const {
+            return Path.empty();
+        }
+
+        explicit operator bool() const {
+            return !Empty();
+        }
+
+        bool operator!() const {
+            return Empty();
+        }
+
+    private:
+        TVector<const FieldDescriptor*> Path;
+    };
+
+}