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, 164 insertions, 0 deletions

diff --git a/library/cpp/skiff/skiff_schema.cpp b/library/cpp/skiff/skiff_schema.cpp
new file mode 100644
index 00000000000..c762896ad02
--- /dev/null
+++ b/library/cpp/skiff/skiff_schema.cpp
@@ -0,0 +1,164 @@
+#include "skiff_schema.h"
+
+#include "skiff.h"
+
+#include <util/generic/hash.h>
+
+namespace NSkiff {
+
+////////////////////////////////////////////////////////////////////////////////
+
+bool operator==(const TSkiffSchema& lhs, const TSkiffSchema& rhs)
+{
+    if (lhs.GetWireType() != rhs.GetWireType() || lhs.GetName() != rhs.GetName()) {
+        return false;
+    }
+    const auto& lhsChildren = lhs.GetChildren();
+    const auto& rhsChildren = rhs.GetChildren();
+    return std::equal(
+        std::begin(lhsChildren),
+        std::end(lhsChildren),
+        std::begin(rhsChildren),
+        std::end(rhsChildren),
+        TSkiffSchemaPtrEqual());
+}
+
+bool operator!=(const TSkiffSchema& lhs, const TSkiffSchema& rhs)
+{
+    return !(lhs == rhs);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+void PrintShortDebugString(const std::shared_ptr<const TSkiffSchema>& schema, IOutputStream* out)
+{
+    (*out) << ToString(schema->GetWireType());
+    if (!IsSimpleType(schema->GetWireType())) {
+        auto children = schema->GetChildren();
+        if (!children.empty()) {
+            (*out) << '<';
+            for (const auto& child : children) {
+                PrintShortDebugString(child, out);
+                (*out) << ';';
+            }
+            (*out) << '>';
+        }
+    }
+}
+
+TString GetShortDebugString(const std::shared_ptr<const TSkiffSchema>& schema)
+{
+    TStringStream out;
+    PrintShortDebugString(schema, &out);
+    return out.Str();
+}
+
+std::shared_ptr<TSimpleTypeSchema> CreateSimpleTypeSchema(EWireType type)
+{
+    return std::make_shared<TSimpleTypeSchema>(type);
+}
+
+static void VerifyNonemptyChildren(const TSkiffSchemaList& children, EWireType wireType)
+{
+    if (children.empty()) {
+        ythrow TSkiffException() << "\"" << ToString(wireType) << "\" must have at least one child";
+    }
+}
+
+std::shared_ptr<TTupleSchema> CreateTupleSchema(TSkiffSchemaList children)
+{
+    return std::make_shared<TTupleSchema>(std::move(children));
+}
+
+std::shared_ptr<TVariant8Schema> CreateVariant8Schema(TSkiffSchemaList children)
+{
+    VerifyNonemptyChildren(children, EWireType::Variant8);
+    return std::make_shared<TVariant8Schema>(std::move(children));
+}
+
+std::shared_ptr<TVariant16Schema> CreateVariant16Schema(TSkiffSchemaList children)
+{
+    VerifyNonemptyChildren(children, EWireType::Variant16);
+    return std::make_shared<TVariant16Schema>(std::move(children));
+}
+
+std::shared_ptr<TRepeatedVariant8Schema> CreateRepeatedVariant8Schema(TSkiffSchemaList children)
+{
+    VerifyNonemptyChildren(children, EWireType::RepeatedVariant8);
+    return std::make_shared<TRepeatedVariant8Schema>(std::move(children));
+}
+
+std::shared_ptr<TRepeatedVariant16Schema> CreateRepeatedVariant16Schema(TSkiffSchemaList children)
+{
+    VerifyNonemptyChildren(children, EWireType::RepeatedVariant16);
+    return std::make_shared<TRepeatedVariant16Schema>(std::move(children));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+TSkiffSchema::TSkiffSchema(EWireType type)
+    : Type_(type)
+{ }
+
+EWireType TSkiffSchema::GetWireType() const
+{
+    return Type_;
+}
+
+std::shared_ptr<TSkiffSchema> TSkiffSchema::SetName(TString name)
+{
+    Name_ = std::move(name);
+    return shared_from_this();
+}
+
+const TString& TSkiffSchema::GetName() const
+{
+    return Name_;
+}
+
+const TSkiffSchemaList& TSkiffSchema::GetChildren() const
+{
+    static const TSkiffSchemaList children;
+    return children;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+TSimpleTypeSchema::TSimpleTypeSchema(EWireType type)
+    : TSkiffSchema(type)
+{
+    Y_VERIFY(IsSimpleType(type));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+size_t TSkiffSchemaPtrHasher::operator()(const std::shared_ptr<TSkiffSchema>& schema) const
+{
+    return THash<NSkiff::TSkiffSchema>()(*schema);
+}
+
+size_t TSkiffSchemaPtrEqual::operator()(
+    const std::shared_ptr<TSkiffSchema>& lhs,
+    const std::shared_ptr<TSkiffSchema>& rhs) const
+{
+    return *lhs == *rhs;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NSkiff
+
+////////////////////////////////////////////////////////////////////////////////
+
+size_t THash<NSkiff::TSkiffSchema>::operator()(const NSkiff::TSkiffSchema &schema) const
+{
+    auto hash = CombineHashes(
+        THash<TString>()(schema.GetName()),
+        static_cast<size_t>(schema.GetWireType()));
+    for (const auto& child : schema.GetChildren()) {
+        hash = CombineHashes(hash, (*this)(*child));
+    }
+    return hash;
+}
+
+////////////////////////////////////////////////////////////////////////////////