ONNX FE handles old API extensions (#12644)

* ONNX FE handles old API extensions
by legacy conversion extension

* Move `LegacyOpExtension` class to dev API

src/core/dev_api/legacy_op_extension.hpp

@@ -0,0 +1,13 @@
+// Copyright (C) 2018-2022 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+//
+
+#pragma once
+
+#include "openvino/core/op_extension.hpp"
+
+namespace ov {
+
+/** @brief Class to distinguish legacy extension. */
+class LegacyOpExtension : public BaseOpExtension {};
+}  // namespace ov

src/frontends/onnx/frontend/include/openvino/frontend/onnx/frontend.hpp

@@ -34,6 +34,7 @@ protected:
     std::vector<Extension::Ptr> m_other_extensions;
     std::vector<DecoderTransformationExtension::Ptr> m_transformation_extensions;
     ExtensionHolder m_extensions;
+    std::once_flag has_legacy_extension;
 };
 
 }  // namespace onnx

src/frontends/onnx/frontend/src/frontend.cpp

@@ -14,6 +14,7 @@
 #include <sstream>
 #include <utils/onnx_internal.hpp>
 
+#include "legacy_op_extension.hpp"
 #include "onnx_common/onnx_model_validator.hpp"
 #include "openvino/frontend/extension/telemetry.hpp"
 #include "ops_bridge.hpp"
@@ -165,5 +166,10 @@ void FrontEnd::add_extension(const std::shared_ptr<ov::Extension>& extension) {
         m_extensions.conversions.push_back(onnx_conv_ext);
     } else if (auto progress_reporter = std::dynamic_pointer_cast<ProgressReporterExtension>(extension)) {
         m_extensions.progress_reporter = progress_reporter;
+    } else if (const auto& legacy_ext = std::dynamic_pointer_cast<ov::LegacyOpExtension>(extension)) {
+        m_other_extensions.push_back(legacy_ext);
+        std::call_once(has_legacy_extension, [this] {
+            m_extensions.conversions.push_back(ngraph::onnx_import::detail::get_legacy_conversion_extension());
+        });
     }
 }

src/frontends/onnx/frontend/src/onnx.cpp

@@ -58,6 +58,9 @@ void unregister_operator(const std::string& name, std::int64_t version, const st
     legacy_conversion_extension->unregister_operator(name, version, domain);
 }
 
+const LegacyConversionExtension::Ptr detail::get_legacy_conversion_extension() {
+    return legacy_conversion_extension;
+}
 }  // namespace onnx_import
 
 }  // namespace ngraph

src/frontends/onnx/frontend/src/utils/onnx_internal.hpp

@@ -7,6 +7,7 @@
 #include <memory>
 #include <string>
 
+#include "legacy_conversion_extension.hpp"
 #include "ngraph/function.hpp"
 #include "openvino/frontend/extension/holder.hpp"
 
@@ -53,6 +54,11 @@ std::shared_ptr<Function> decode_to_framework_nodes(std::shared_ptr<ONNX_NAMESPA
 ///
 /// \return    A nGraph function.
 void convert_decoded_function(std::shared_ptr<Function> function);
+
+/// \brief Get the legacy conversion extension.
+///
+/// \return const LegacyConversionExtension::Ptr
+const LegacyConversionExtension::Ptr get_legacy_conversion_extension();
 }  // namespace detail
 }  // namespace onnx_import
 }  // namespace ngraph

src/inference/src/ie_network_reader.cpp

@@ -24,6 +24,7 @@
 #endif
 #include "ie_itt.hpp"
 #include "legacy/ie_reader.hpp"
+#include "legacy_op_extension.hpp"
 #include "ngraph/function.hpp"
 #include "ngraph/type/element_type.hpp"
 #include "ngraph/variant.hpp"
@@ -41,7 +42,7 @@ namespace ov {
 /*
  * @brief Wrapper for old IE extensions to new API
  */
-class ExtensionWrapper : public ov::BaseOpExtension {
+class ExtensionWrapper : public ov::LegacyOpExtension {
 public:
     ExtensionWrapper(const InferenceEngine::IExtensionPtr& ext, const std::string& opset, const std::string& name)
         : m_ext(ext),

src/tests/functional/inference_engine/ir_serialization/custom_ops.cpp

@@ -42,6 +42,7 @@ protected:
     void TearDown() override {
         std::remove(m_out_xml_path.c_str());
         std::remove(m_out_bin_path.c_str());
+        ov::shutdown();
     }
 };
 
@@ -70,7 +71,7 @@ TEST_F(CustomOpsSerializationTest, CustomOpUser_MO) {
 // a shared library for ONNX don't make sence in static OpenVINO build
 #ifndef OPENVINO_STATIC_LIBRARY
 
-TEST_F(CustomOpsSerializationTest, DISABLED_CustomOpUser_ONNXImporter) {
+TEST_F(CustomOpsSerializationTest, CustomOpUser_ONNXImporter) {
     const std::string model = CommonTestUtils::getModelFromTestModelZoo(IR_SERIALIZATION_MODELS_PATH "custom_op.onnx");
 
     InferenceEngine::Core ie;