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, 51 insertions, 0 deletions

diff --git a/library/cpp/skiff/zerocopy_output_writer-inl.h b/library/cpp/skiff/zerocopy_output_writer-inl.h
new file mode 100644
index 0000000000..6bd067c9fa
--- /dev/null
+++ b/library/cpp/skiff/zerocopy_output_writer-inl.h
@@ -0,0 +1,51 @@
+#pragma once
+#ifndef ZEROCOPY_OUTPUT_WRITER_INL_H_
+#error "Direct inclusion of this file is not allowed, include zerocopy_output_writer.h"
+// For the sake of sane code completion.
+#include "zerocopy_output_writer.h"
+#endif
+
+#include <util/system/yassert.h>
+
+namespace NSkiff {
+
+////////////////////////////////////////////////////////////////////////////////
+
+char* TZeroCopyOutputStreamWriter::Current() const
+{
+    return Current_;
+}
+
+ui64 TZeroCopyOutputStreamWriter::RemainingBytes() const
+{
+    return RemainingBytes_;
+}
+
+void TZeroCopyOutputStreamWriter::Advance(size_t bytes)
+{
+    Y_VERIFY(bytes <= RemainingBytes_);
+    Current_ += bytes;
+    RemainingBytes_ -= bytes;
+}
+
+void TZeroCopyOutputStreamWriter::Write(const void* buffer, size_t length)
+{
+    if (length > RemainingBytes_) {
+        UndoRemaining();
+        Output_->Write(buffer, length);
+        TotalWrittenBlockSize_ += length;
+        ObtainNextBlock();
+    } else {
+        memcpy(Current_, buffer, length);
+        Advance(length);
+    }
+}
+
+ui64 TZeroCopyOutputStreamWriter::GetTotalWrittenSize() const
+{
+    return TotalWrittenBlockSize_ - RemainingBytes_;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NSkiff