1 files changed, 111 insertions, 0 deletions
diff --git a/library/cpp/protobuf/json/string_transform.h b/library/cpp/protobuf/json/string_transform.h
new file mode 100644
index 0000000000..e4b296bc01
--- /dev/null
+++ b/library/cpp/protobuf/json/string_transform.h
@@ -0,0 +1,111 @@
+#pragma once
+
+#include <library/cpp/string_utils/relaxed_escaper/relaxed_escaper.h>
+#include <util/generic/ptr.h>
+#include <util/generic/refcount.h>
+
+namespace NProtobufJson {
+    class IStringTransform: public TSimpleRefCount<IStringTransform> {
+    public:
+        virtual ~IStringTransform() {
+        }
+
+        /// Some transforms have special meaning.
+        /// For example, escape transforms cause generic JSON escaping to be turned off.
+        enum Type {
+            EscapeTransform = 0x1,
+        };
+
+        virtual int GetType() const = 0;
+
+        /// This method is called for each string field in proto
+        virtual void Transform(TString& str) const = 0;
+
+        /// This method is called for each bytes field in proto
+        virtual void TransformBytes(TString& str) const {
+            // Default behaviour is to apply string transform
+            return Transform(str);
+        }
+    };
+
+    using TStringTransformPtr = TIntrusivePtr<IStringTransform>;
+
+    template <bool quote, bool tounicode>
+    class TEscapeJTransform: public IStringTransform {
+    public:
+        int GetType() const override {
+            return EscapeTransform;
+        }
+
+        void Transform(TString& str) const override {
+            TString newStr;
+            NEscJ::EscapeJ<quote, tounicode>(str, newStr);
+            str = newStr;
+        }
+    };
+
+    class TCEscapeTransform: public IStringTransform {
+    public:
+        int GetType() const override {
+            return EscapeTransform;
+        }
+
+        void Transform(TString& str) const override;
+    };
+
+    class TSafeUtf8CEscapeTransform: public IStringTransform {
+    public:
+        int GetType() const override {
+            return EscapeTransform;
+        }
+
+        void Transform(TString& str) const override;
+    };
+
+    class TDoubleEscapeTransform: public IStringTransform {
+    public:
+        int GetType() const override {
+            return EscapeTransform;
+        }
+
+        void Transform(TString& str) const override;
+    };
+
+    class TDoubleUnescapeTransform: public NProtobufJson::IStringTransform {
+    public:
+        int GetType() const override {
+            return NProtobufJson::IStringTransform::EscapeTransform;
+        }
+
+        void Transform(TString& str) const override;
+
+    private:
+        TString Unescape(const TString& str) const;
+    };
+
+    class TBase64EncodeBytesTransform: public NProtobufJson::IStringTransform {
+    public:
+        int GetType() const override {
+            return 0;
+        }
+
+        void Transform(TString&) const override {
+            // Do not transform strings
+        }
+
+        void TransformBytes(TString &str) const override;
+    };
+
+    class TBase64DecodeBytesTransform: public NProtobufJson::IStringTransform {
+    public:
+        int GetType() const override {
+            return 0;
+        }
+
+        void Transform(TString&) const override {
+            // Do not transform strings
+        }
+
+        void TransformBytes(TString &str) const override;
+    };
+}