YT-19324: move YT provider to ydb/library/yql

This commit is formed by the following script: https://paste.yandex-team.ru/6f92e4b8-efc5-4d34-948b-15ee2accd7e7/text.
This commit has zero effect on all projects that depend on YQL.

The summary of changes:
- `yql/providers/yt -> ydb/library/yql/providers/yt `- the whole implementation of YT provider is moved into YDB code base for further export as a part of YT YQL plugin shared library;
- `yql/providers/stat/{expr_nodes,uploader} -> ydb/library/yql/providers/stat/{expr_nodes,uploader}` - a small interface without implementation and the description of stat expr nodes;
- `yql/core/extract_predicate/ut -> ydb/library/yql/core/extract_predicate/ut`;
- `yql/core/{ut,ut_common} -> ydb/library/yql/core/{ut,ut_common}`;
- `yql/core` is gone;
- `yql/library/url_preprocessing -> ydb/library/yql/core/url_preprocessing`.

**NB**: all new targets inside `ydb/` are under `IF (NOT CMAKE_EXPORT)` clause which disables them from open-source cmake generation and ya make build. They will be enabled in the subsequent commits.

2 files changed, 48 insertions, 0 deletions

diff --git a/library/cpp/yson_pull/bridge.h b/library/cpp/yson_pull/bridge.h
new file mode 100644
index 0000000000..ac767dcba0
--- /dev/null
+++ b/library/cpp/yson_pull/bridge.h
@@ -0,0 +1,34 @@
+#pragma once
+
+#include "consumer.h"
+#include "event.h"
+#include "writer.h"
+
+namespace NYsonPull {
+    //! \brief Connect YSON stream producer and consumer.
+    //!
+    //! Useful for writing YSON stream filters.
+    //! \p Producer must have a \p next_event() method (like \p NYsonPull::reader).
+    //! \p Consumer must be like \p NYsonPull::consumer interface.
+    template <typename Producer, typename Consumer>
+    inline void Bridge(Producer&& producer, Consumer&& consumer) {
+        for (;;) {
+            auto& event = producer.NextEvent();
+            consumer.OnEvent(event);
+            if (event.Type() == EEventType::EndStream) {
+                break;
+            }
+        }
+    }
+
+    template <typename Producer>
+    inline void Bridge(Producer&& producer, TWriter& writer_) {
+        Bridge(std::forward<Producer>(producer), writer_.GetConsumer());
+    }
+
+    template <typename Producer>
+    inline void Bridge(Producer&& producer, TWriter&& writer_) {
+        Bridge(std::forward<Producer>(producer), writer_.GetConsumer());
+    }
+
+}
diff --git a/library/cpp/yson_pull/yson.h b/library/cpp/yson_pull/yson.h
new file mode 100644
index 0000000000..a77eaa5c94
--- /dev/null
+++ b/library/cpp/yson_pull/yson.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include "bridge.h"
+#include "consumer.h"
+#include "event.h"
+#include "exceptions.h"
+#include "input.h"
+#include "output.h"
+#include "position_info.h"
+#include "range.h"
+#include "reader.h"
+#include "scalar.h"
+#include "stream_type.h"
+#include "writer.h"