Merge pull request #18493 from TolyaTalamanov:at/wrap-streaming

[G-API Wrap streaming

* Wrap streaming

* Fix build

* Add comments

* Remove comment

* Fix comments to review

* Add test for python pull overload

modules/gapi/misc/python/pyopencv_gapi.hpp

@@ -3,7 +3,14 @@
 
 #ifdef HAVE_OPENCV_GAPI
 
+// NB: Python wrapper replaces :: with _ for classes
 using gapi_GKernelPackage = cv::gapi::GKernelPackage;
+using gapi_wip_IStreamSource_Ptr = cv::Ptr<cv::gapi::wip::IStreamSource>;
+
+// FIXME: Python wrapper generate code without namespace std,
+// so it cause error: "string wasn't declared"
+// WA: Create using
+using std::string;
 
 template<>
 bool pyopencv_to(PyObject* obj, std::vector<GCompileArg>& value, const ArgInfo& info)
@@ -78,6 +85,18 @@ PyObject* pyopencv_from(const GRunArgs& value)
     return list;
 }
 
+template<>
+bool pyopencv_to(PyObject* obj, GMetaArgs& value, const ArgInfo& info)
+{
+    return pyopencv_to_generic_vec(obj, value, info);
+}
+
+template<>
+PyObject* pyopencv_from(const GMetaArgs& value)
+{
+    return pyopencv_from_generic_vec(value);
+}
+
 template <typename T>
 static PyObject* extract_proto_args(PyObject* py_args, PyObject* kw)
 {
@@ -151,6 +170,19 @@ static PyObject* pyopencv_cv_gin(PyObject* , PyObject* py_args, PyObject* kw)
                 return NULL;
             }
         }
+        else if (PyObject_TypeCheck(item,
+                    reinterpret_cast<PyTypeObject*>(pyopencv_gapi_wip_IStreamSource_TypePtr)))
+        {
+            cv::gapi::wip::IStreamSource::Ptr source =
+                reinterpret_cast<pyopencv_gapi_wip_IStreamSource_t*>(item)->v;
+            args.emplace_back(source);
+        }
+        else
+        {
+            PyErr_SetString(PyExc_TypeError, "cv.gin can works only with cv::Mat,"
+                                             "cv::Scalar, cv::gapi::wip::IStreamSource::Ptr");
+            return NULL;
+        }
     }
 
     return pyopencv_from_generic_vec(args);