Merge pull request #18419 from TolyaTalamanov:at/generic-inference

[G-API] Introduce generic version for cv::gapi::infer

* Introduce generic infer

* Move Generic to infer.hpp

* Removew num_outs

* Fix windows warnings

* Fix comments to review

* Fix doxygen

* Add comment

* Fix comments to review

* standoalone ifdef in ginfer.cpp

* Fix test

modules/gapi/include/opencv2/gapi/gcall.hpp

@@ -56,11 +56,16 @@ public:
     Priv& priv();
     const Priv& priv() const;
 
-protected:
-    std::shared_ptr<Priv> m_priv;
+    // GKernel and params can be modified, it's needed for infer<Generic>,
+    // because information about output shapes doesn't exist in compile time
+    GKernel& kernel();
+    cv::util::any& params();
 
     void setArgs(std::vector<GArg> &&args);
 
+protected:
+    std::shared_ptr<Priv> m_priv;
+
     // Public versions return a typed array or opaque, those are implementation details
     detail::GArrayU yieldArray(int output = 0);
     detail::GOpaqueU yieldOpaque(int output = 0);

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

@@ -121,6 +121,45 @@ struct GInferBase {
     }
 };
 
+// Struct stores network input/output names.
+// Used by infer<Generic>
+struct InOutInfo
+{
+    std::vector<std::string> in_names;
+    std::vector<std::string> out_names;
+};
+
+/**
+ * @{
+ * @brief G-API object used to collect network inputs
+ */
+class GAPI_EXPORTS GInferInputs
+{
+public:
+    cv::GMat& operator[](const std::string& name);
+    const std::unordered_map<std::string, cv::GMat>& getBlobs() const;
+
+private:
+    std::unordered_map<std::string, cv::GMat> in_blobs;
+};
+/** @} */
+
+/**
+ * @{
+ * @brief G-API object used to collect network outputs
+ */
+struct GAPI_EXPORTS GInferOutputs
+{
+public:
+    GInferOutputs(std::shared_ptr<cv::GCall> call);
+    cv::GMat at(const std::string& name);
+
+private:
+    std::shared_ptr<cv::GCall> m_call;
+    InOutInfo* m_info = nullptr;
+    std::unordered_map<std::string, cv::GMat> out_blobs;
+};
+/** @} */
 
 // Base "Infer list" kernel.
 // All notes from "Infer" kernel apply here as well.
@@ -254,6 +293,45 @@ typename Net::Result infer(Args&&... args) {
     return GInfer<Net>::on(std::forward<Args>(args)...);
 }
 
+/**
+ * @brief Special network type
+ */
+struct Generic { };
+
+/**
+ * @brief Calculates response for generic network
+ *
+ * @param tag a network tag
+ * @param inputs networks's inputs
+ * @return a GInferOutputs
+ */
+template<typename T = Generic> GInferOutputs
+infer(const std::string& tag, const GInferInputs& inputs)
+{
+    std::vector<GArg> input_args;
+    std::vector<std::string> input_names;
+
+    const auto& blobs = inputs.getBlobs();
+    for (auto&& p : blobs)
+    {
+        input_names.push_back(p.first);
+        input_args.emplace_back(p.second);
+    }
+
+    GKinds kinds(blobs.size(), cv::detail::OpaqueKind::CV_MAT);
+    auto call = std::make_shared<cv::GCall>(GKernel{
+                GInferBase::id(),
+                tag,
+                GInferBase::getOutMeta,
+                {}, // outShape will be filled later
+                std::move(kinds)
+            });
+
+    call->setArgs(std::move(input_args));
+    call->params() = InOutInfo{input_names, {}};
+
+    return GInferOutputs{std::move(call)};
+}
 
 } // namespace gapi
 } // namespace cv

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

@@ -17,6 +17,7 @@
 
 #include <opencv2/core/cvdef.h>     // GAPI_EXPORTS
 #include <opencv2/gapi/gkernel.hpp> // GKernelPackage
+#include <opencv2/gapi/infer.hpp>   // Generic
 
 namespace cv {
 namespace gapi {
@@ -58,6 +59,8 @@ namespace detail {
         // (e.g. topology's partial execution)
         std::size_t num_in;  // How many inputs are defined in the operation
         std::size_t num_out; // How many outputs are defined in the operation
+
+        bool is_generic;
     };
 } // namespace detail
 
@@ -80,7 +83,7 @@ public:
         : desc{ model, weights, device, {}, {}, {}
               , std::tuple_size<typename Net::InArgs>::value  // num_in
               , std::tuple_size<typename Net::OutArgs>::value // num_out
-              } {
+              , false} {
     };
 
     Params<Net>& cfgInputLayers(const typename PortCfg<Net>::In &ll) {
@@ -107,15 +110,36 @@ public:
     }
 
     // BEGIN(G-API's network parametrization API)
-    GBackend      backend() const { return cv::gapi::ie::backend();  }
-    std::string   tag()     const { return Net::tag(); }
-    cv::util::any params()  const { return { desc }; }
+    GBackend      backend()    const { return cv::gapi::ie::backend();  }
+    std::string   tag()        const { return Net::tag(); }
+    cv::util::any params()     const { return { desc }; }
     // END(G-API's network parametrization API)
 
 protected:
     detail::ParamDesc desc;
 };
 
+template<>
+class Params<cv::gapi::Generic> {
+public:
+    Params(const std::string& tag,
+           const std::string &model,
+           const std::string &weights,
+           const std::string &device)
+        : desc{ model, weights, device, {}, {}, {}, 0u, 0u, true}, m_tag(tag) {
+    };
+
+    // BEGIN(G-API's network parametrization API)
+    GBackend      backend()    const { return cv::gapi::ie::backend();  }
+    std::string   tag()        const { return m_tag; }
+    cv::util::any params()     const { return { desc }; }
+    // END(G-API's network parametrization API)
+
+protected:
+    detail::ParamDesc desc;
+    std::string m_tag;
+};
+
 } // namespace ie
 } // namespace gapi
 } // namespace cv