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, 62 insertions, 0 deletions

diff --git a/yt/cpp/mapreduce/common/debug_metrics.cpp b/yt/cpp/mapreduce/common/debug_metrics.cpp
new file mode 100644
index 00000000000..6235e55f7e6
--- /dev/null
+++ b/yt/cpp/mapreduce/common/debug_metrics.cpp
@@ -0,0 +1,62 @@
+#include "debug_metrics.h"
+
+#include <util/generic/hash.h>
+#include <util/generic/singleton.h>
+
+#include <util/string/cast.h>
+#include <util/system/mutex.h>
+
+namespace NYT {
+namespace NDetail {
+
+////////////////////////////////////////////////////////////////////////////////
+
+class TDebugMetrics {
+public:
+    static TDebugMetrics& Get()
+    {
+        return *Singleton<TDebugMetrics>();
+    }
+
+    void Inc(TStringBuf name)
+    {
+        auto g = Guard(Lock_);
+        auto it = Metrics_.find(name);
+        if (it == Metrics_.end()) {
+            it = Metrics_.emplace(ToString(name), 0).first;
+        }
+        ++it->second;
+    }
+
+    ui64 Get(TStringBuf name) const
+    {
+        auto g = Guard(Lock_);
+        auto it = Metrics_.find(name);
+        if (it == Metrics_.end()) {
+            return 0;
+        } else {
+            return it->second;
+        }
+    }
+
+private:
+    TMutex Lock_;
+    THashMap<TString, ui64> Metrics_;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+void IncDebugMetricImpl(TStringBuf name)
+{
+    TDebugMetrics::Get().Inc(name);
+}
+
+ui64 GetDebugMetric(TStringBuf name)
+{
+    return TDebugMetrics::Get().Get(name);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NDetail
+} // namespace NYT