intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

4 files changed, 149 insertions, 0 deletions

diff --git a/library/cpp/yt/yson/consumer.cpp b/library/cpp/yt/yson/consumer.cpp
new file mode 100644
index 0000000000..9b68ee8a22
--- /dev/null
+++ b/library/cpp/yt/yson/consumer.cpp
@@ -0,0 +1,16 @@
+#include "consumer.h"
+
+#include <library/cpp/yt/yson_string/string.h>
+
+namespace NYT::NYson {
+
+////////////////////////////////////////////////////////////////////////////////
+
+void IYsonConsumer::OnRaw(const TYsonStringBuf& yson)
+{
+    OnRaw(yson.AsStringBuf(), yson.GetType());
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NYson
diff --git a/library/cpp/yt/yson/consumer.h b/library/cpp/yt/yson/consumer.h
new file mode 100644
index 0000000000..ea5f586b91
--- /dev/null
+++ b/library/cpp/yt/yson/consumer.h
@@ -0,0 +1,111 @@
+#pragma once
+
+#include <util/generic/strbuf.h>
+
+#include <util/system/defaults.h>
+
+#include <library/cpp/yt/yson_string/public.h>
+
+namespace NYT::NYson {
+
+////////////////////////////////////////////////////////////////////////////////
+
+//! A SAX-like interface for parsing a YSON stream.
+struct IYsonConsumer
+{
+    virtual ~IYsonConsumer() = default;
+
+    //! The current item is a string scalar (IStringNode).
+    /*!
+     *  \param value A scalar value.
+     */
+    virtual void OnStringScalar(TStringBuf value) = 0;
+
+    //! The current item is an integer scalar (IInt64Node).
+    /*!
+     *  \param value A scalar value.
+     */
+    virtual void OnInt64Scalar(i64 value) = 0;
+
+    //! The current item is an integer scalar (IUint64Node).
+    /*!
+     *  \param value A scalar value.
+     */
+    virtual void OnUint64Scalar(ui64 scalar) = 0;
+
+    //! The current item is an FP scalar (IDoubleNode).
+    /*!
+     *  \param value A scalar value.
+     */
+    virtual void OnDoubleScalar(double value) = 0;
+
+    //! The current item is an boolean scalar (IBooleanNode).
+    /*!
+     *  \param value A scalar value.
+     */
+    virtual void OnBooleanScalar(bool value) = 0;
+
+    //! The current item is an entity (IEntityNode).
+    virtual void OnEntity() = 0;
+
+    //! Starts a list (IListNode).
+    /*!
+     *  The events describing a list are raised as follows:
+     *  - #OnBeginList
+     *  - For each item: #OnListItem followed by the description of the item
+     *  - #OnEndList
+     */
+    virtual void OnBeginList() = 0;
+
+    //! Designates a list item.
+    virtual void OnListItem() = 0;
+
+    //! Ends the current list.
+    virtual void OnEndList() = 0;
+
+    //! Starts a map (IMapNode).
+    /*!
+     *  The events describing a map are raised as follows:
+     *  - #OnBeginMap
+     *  - For each item: #OnKeyedItem followed by the description of the item
+     *  - #OnEndMap
+     */
+    virtual void OnBeginMap() = 0;
+
+    //! Designates a keyed item (in map or in attributes).
+    /*!
+     *  \param key Item key in the map.
+     */
+    virtual void OnKeyedItem(TStringBuf key) = 0;
+
+    //! Ends the current map.
+    virtual void OnEndMap() = 0;
+
+    //! Starts attributes.
+    /*!
+     *  An arbitrary node may be preceeded by attributes.
+     *
+     *  The events describing attributes are raised as follows:
+     *  - #OnBeginAttributes
+     *  - For each item: #OnKeyedItem followed by the description of the item
+     *  - #OnEndAttributes
+     */
+    virtual void OnBeginAttributes() = 0;
+
+    //! Ends the current attribute list.
+    virtual void OnEndAttributes() = 0;
+
+    //! Inserts YSON-serialized node or fragment.
+    /*!
+     *  \param yson Serialized data.
+     *  \param type Type of data.
+     */
+    virtual void OnRaw(TStringBuf yson, EYsonType type) = 0;
+
+    // Extension methods.
+    void OnRaw(const TYsonStringBuf& yson);
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NYson
diff --git a/library/cpp/yt/yson/public.h b/library/cpp/yt/yson/public.h
new file mode 100644
index 0000000000..68cdcd38c1
--- /dev/null
+++ b/library/cpp/yt/yson/public.h
@@ -0,0 +1,11 @@
+#pragma once
+
+namespace NYT::NYson {
+
+////////////////////////////////////////////////////////////////////////////////
+
+struct IYsonConsumer;
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NYson
diff --git a/library/cpp/yt/yson/ya.make b/library/cpp/yt/yson/ya.make
new file mode 100644
index 0000000000..d914352c4b
--- /dev/null
+++ b/library/cpp/yt/yson/ya.make
@@ -0,0 +1,11 @@
+LIBRARY()
+
+SRCS(
+    consumer.cpp
+)
+
+PEERDIR(
+    library/cpp/yt/yson_string
+)
+
+END()