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.

1 files changed, 38 insertions, 0 deletions

diff --git a/yt/cpp/mapreduce/client/file_writer.h b/yt/cpp/mapreduce/client/file_writer.h
new file mode 100644
index 0000000000..f3b97b904e
--- /dev/null
+++ b/yt/cpp/mapreduce/client/file_writer.h
@@ -0,0 +1,38 @@
+#pragma once
+
+#include "retryful_writer.h"
+
+#include <yt/cpp/mapreduce/common/fwd.h>
+
+#include <yt/cpp/mapreduce/interface/io.h>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+class TFileWriter
+    : public IFileWriter
+{
+public:
+    TFileWriter(
+        const TRichYPath& path,
+        IClientRetryPolicyPtr clientRetryPolicy,
+        ITransactionPingerPtr transactionPinger,
+        const TClientContext& context,
+        const TTransactionId& transactionId,
+        const TFileWriterOptions& options = TFileWriterOptions());
+
+    ~TFileWriter() override;
+
+protected:
+    void DoWrite(const void* buf, size_t len) override;
+    void DoFinish() override;
+
+private:
+    TRetryfulWriter RetryfulWriter_;
+    static const size_t BUFFER_SIZE = 64 << 20;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT