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

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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, 71 insertions, 0 deletions

diff --git a/yt/cpp/mapreduce/interface/init.h b/yt/cpp/mapreduce/interface/init.h
new file mode 100644
index 0000000000..302be268fc
--- /dev/null
+++ b/yt/cpp/mapreduce/interface/init.h
@@ -0,0 +1,71 @@
+#pragma once
+
+///
+/// @file yt/cpp/mapreduce/interface/init.h
+///
+/// Initialization functions of YT Wrapper.
+
+#include <yt/cpp/mapreduce/interface/wait_proxy.h>
+
+#include <util/generic/fwd.h>
+
+#include <functional>
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+/// Options for @ref NYT::Initialize() and @ref NYT::JoblessInitialize() functions
+struct TInitializeOptions
+{
+    using TSelf = TInitializeOptions;
+
+    ///
+    /// @brief Override waiting functions for YT Wrapper.
+    ///
+    /// This options allows to override functions used by this library to wait something.
+    FLUENT_FIELD_DEFAULT(::TIntrusivePtr<IWaitProxy>, WaitProxy, nullptr);
+
+    ///
+    /// @brief Enable/disable cleanup when program execution terminates abnormally.
+    ///
+    /// When set to true, library will abort all active transactions and running operations when program
+    /// terminates on error or signal.
+    FLUENT_FIELD_DEFAULT(bool, CleanupOnTermination, false);
+
+    ///
+    /// @brief Set callback to be called before exit() in job mode.
+    ///
+    /// Provided function will be called just before exit() when program is started in job mode.
+    /// This might be useful for shutting down libraries that are used inside operations.
+    ///
+    /// NOTE: Keep in mind that inside job execution environment differs from client execution environment.
+    /// So JobOnExitFunction should not depend on argc/argv environment variables etc.
+    FLUENT_FIELD_OPTION(std::function<void()>, JobOnExitFunction);
+};
+
+///
+/// @brief Performs basic initialization (logging, termination handlers, etc).
+///
+/// This function never switches to job mode.
+void JoblessInitialize(const TInitializeOptions& options = TInitializeOptions());
+
+///
+/// @brief Performs basic initialization and switches to a job mode if required.
+///
+/// This function performs basic initialization (it sets up logging reads the config, etc) and checks if binary is launched
+/// on YT machine inside a job. If latter is true this function launches proper job and after job is done it calls exit().
+///
+/// This function must be called if application starts any operation.
+/// This function must be called immediately after entering main() function before any argument parsing is done.
+void Initialize(int argc, const char **argv, const TInitializeOptions &options = TInitializeOptions());
+
+/// Similar to @ref NYT::Initialize(int, const char**, const TInitializeOptions&)
+void Initialize(int argc, char **argv, const TInitializeOptions &options = TInitializeOptions());
+
+/// Similar to @ref NYT::Initialize(int, const char**, const TInitializeOptions&)
+void Initialize(const TInitializeOptions &options = TInitializeOptions());
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT