Merge pull request #27549 from atamas19:tensor_naming_functionality

G-API: Implement cfgEnsureNamedTensors option to OpenVINO Params #27549

Added the option cfgEnsureNamedTensors to be applied on OpenVINO models with nameless tensors. If a tensor doesn't have a name, it sets a default one. The default name is created using OpenVINO's standard `make_default_tensor_name` . `make_default_tensor_name`  had to be rewritten because it is only available in OpenVINO's dev_api.

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake

modules/gapi/include/opencv2/gapi/infer/ov.hpp

@@ -99,6 +99,8 @@ struct ParamDesc {
     PluginConfigT config;
 
     size_t nireq = 1;
+
+    bool ensure_named_tensors = false;
 };
 
 // NB: Just helper to avoid code duplication.
@@ -205,6 +207,24 @@ public:
         return *this;
     }
 
+    /** @brief Ensures the model has named tensors.
+
+    This function is used to ensure that all tensors in the model have names.
+    It goes through all input and output nodes of the model and sets the names
+    if they are not set. This is neccessary for models with nameless tensors.
+
+    If a tensor does not have a name, it will be assigned a default name
+    based on the producer node's friendly name. If the producer node has multiple
+    outputs, the name will be in the form "node_name:N", where N is the output index.
+
+    @param flag If true, then it guarantees that all tensors will have names.
+    @return reference to this parameter structure.
+     */
+    Params<Net>& cfgEnsureNamedTensors(bool flag = true) {
+        m_desc.ensure_named_tensors = flag;
+        return *this;
+    }
+
     /** @brief Specifies tensor layout for an input layer.
 
     The function is used to set tensor layout for an input layer.
@@ -524,6 +544,12 @@ public:
         return *this;
     }
 
+    /** @see ov::Params::cfgEnsureNamedTensors. */
+    Params& cfgEnsureNamedTensors(bool flag = true) {
+        m_desc.ensure_named_tensors = flag;
+        return *this;
+    }
+
     /** @see ov::Params::cfgInputTensorLayout. */
     Params& cfgInputTensorLayout(std::string layout) {
         detail::getModelToSetAttrOrThrow(m_desc.kind, "input tensor layout")

modules/gapi/src/backends/ov/govbackend.cpp

@@ -69,6 +69,27 @@ ov::Core cv::gapi::ov::wrap::getCore() {
         ? create_OV_Core_pointer() : create_OV_Core_instance();
 }
 
+static std::string make_default_tensor_name(const ov::Output<const ov::Node>& output) {
+    auto default_name = output.get_node()->get_friendly_name();
+    if (output.get_node()->get_output_size() > 1) {
+        default_name += ':' + std::to_string(output.get_index());
+    }
+    return default_name;
+}
+
+static void ensureNamedTensors(std::shared_ptr<ov::Model> model) {
+    for (auto& input : model->inputs()) {
+        if (input.get_names().empty()) {
+            input.set_names({make_default_tensor_name(input)});
+        }
+    }
+    for (auto& output : model->outputs()) {
+        if (output.get_names().empty()) {
+            output.set_names({make_default_tensor_name(output)});
+        }
+    }
+}
+
 static ov::AnyMap toOV(const ParamDesc::PluginConfigT &config) {
     return {config.begin(), config.end()};
 }
@@ -236,6 +257,10 @@ struct OVUnit {
                 .read_model(desc.model_path, desc.bin_path);
             GAPI_Assert(model);
 
+            if (params.ensure_named_tensors) {
+                ensureNamedTensors(model);
+            }
+
             if (params.num_in == 1u && params.input_names.empty()) {
                 params.input_names = { model->inputs().begin()->get_any_name() };
             }