Merge pull request #18452 from smirnov-alexey:as/export_serialization_api

[G-API] Export a part of serialization interface

* Initial stub

* Add test on serialization of a custom type

* Namespaces rework

* Fix isSupported in test struct

* Fix clang build and rework namespaces

* Remove redundant header

modules/gapi/include/opencv2/gapi/gcomputation.hpp

@@ -37,14 +37,12 @@ namespace detail
 }
 
 // Forward-declare the serialization objects
-namespace gimpl {
+namespace gapi {
 namespace s11n {
-namespace I {
-    struct IStream;
-    struct OStream;
-} // namespace I
+    struct IIStream;
+    struct IOStream;
 } // namespace s11n
-} // namespace gimpl
+} // namespace gapi
 
 /**
  * \addtogroup gapi_main_classes
@@ -509,9 +507,9 @@ public:
     /// @private
     const Priv& priv() const;
     /// @private
-    explicit GComputation(cv::gimpl::s11n::I::IStream &);
+    explicit GComputation(cv::gapi::s11n::IIStream &);
     /// @private
-    void serialize(cv::gimpl::s11n::I::OStream &) const;
+    void serialize(cv::gapi::s11n::IOStream &) const;
 
 protected:
 

modules/gapi/include/opencv2/gapi/s11n.hpp

@@ -8,6 +8,8 @@
 #define OPENCV_GAPI_S11N_HPP
 
 #include <vector>
+#include <map>
+#include <unordered_map>
 #include <opencv2/gapi/gcomputation.hpp>
 
 namespace cv {
@@ -51,7 +53,138 @@ cv::GRunArgs deserialize(const std::vector<char> &p) {
     return detail::getRunArgs(p);
 }
 
+} // namespace gapi
+} // namespace cv
 
+namespace cv {
+namespace gapi {
+namespace s11n {
+struct GAPI_EXPORTS IOStream {
+    virtual ~IOStream() = default;
+    // Define the native support for basic C++ types at the API level:
+    virtual IOStream& operator<< (bool) = 0;
+    virtual IOStream& operator<< (char) = 0;
+    virtual IOStream& operator<< (unsigned char) = 0;
+    virtual IOStream& operator<< (short) = 0;
+    virtual IOStream& operator<< (unsigned short) = 0;
+    virtual IOStream& operator<< (int) = 0;
+    virtual IOStream& operator<< (uint32_t) = 0;
+    virtual IOStream& operator<< (uint64_t) = 0;
+    virtual IOStream& operator<< (float) = 0;
+    virtual IOStream& operator<< (double) = 0;
+    virtual IOStream& operator<< (const std::string&) = 0;
+};
+
+struct GAPI_EXPORTS IIStream {
+    virtual ~IIStream() = default;
+    virtual IIStream& operator>> (bool &) = 0;
+    virtual IIStream& operator>> (std::vector<bool>::reference) = 0;
+    virtual IIStream& operator>> (char &) = 0;
+    virtual IIStream& operator>> (unsigned char &) = 0;
+    virtual IIStream& operator>> (short &) = 0;
+    virtual IIStream& operator>> (unsigned short &) = 0;
+    virtual IIStream& operator>> (int &) = 0;
+    virtual IIStream& operator>> (float &) = 0;
+    virtual IIStream& operator>> (double &) = 0;
+    virtual IIStream& operator >> (uint32_t &) = 0;
+    virtual IIStream& operator >> (uint64_t &) = 0;
+    virtual IIStream& operator>> (std::string &) = 0;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////
+// S11N operators
+// Note: operators for basic types are defined in IIStream/IOStream
+
+// OpenCV types ////////////////////////////////////////////////////////////////
+
+GAPI_EXPORTS IOStream& operator<< (IOStream& os, const cv::Point &pt);
+GAPI_EXPORTS IIStream& operator>> (IIStream& is,       cv::Point &pt);
+
+GAPI_EXPORTS IOStream& operator<< (IOStream& os, const cv::Size &sz);
+GAPI_EXPORTS IIStream& operator>> (IIStream& is,       cv::Size &sz);
+
+GAPI_EXPORTS IOStream& operator<< (IOStream& os, const cv::Rect &rc);
+GAPI_EXPORTS IIStream& operator>> (IIStream& is,       cv::Rect &rc);
+
+GAPI_EXPORTS IOStream& operator<< (IOStream& os, const cv::Scalar &s);
+GAPI_EXPORTS IIStream& operator>> (IIStream& is,       cv::Scalar &s);
+
+GAPI_EXPORTS IOStream& operator<< (IOStream& os, const cv::Mat &m);
+GAPI_EXPORTS IIStream& operator>> (IIStream& is,       cv::Mat &m);
+
+// Generic STL types ////////////////////////////////////////////////////////////////
+template<typename K, typename V>
+IOStream& operator<< (IOStream& os, const std::map<K, V> &m) {
+    const uint32_t sz = static_cast<uint32_t>(m.size());
+    os << sz;
+    for (const auto& it : m) os << it.first << it.second;
+    return os;
+}
+template<typename K, typename V>
+IIStream& operator>> (IIStream& is, std::map<K, V> &m) {
+    m.clear();
+    uint32_t sz = 0u;
+    is >> sz;
+    for (std::size_t i = 0; i < sz; ++i) {
+        K k{};
+        V v{};
+        is >> k >> v;
+        m[k] = v;
+    }
+    return is;
+}
+template<typename K, typename V>
+IOStream& operator<< (IOStream& os, const std::unordered_map<K, V> &m) {
+    const uint32_t sz = static_cast<uint32_t>(m.size());
+    os << sz;
+    for (auto &&it : m) os << it.first << it.second;
+    return os;
+}
+template<typename K, typename V>
+IIStream& operator>> (IIStream& is, std::unordered_map<K, V> &m) {
+    m.clear();
+    uint32_t sz = 0u;
+    is >> sz;
+    for (std::size_t i = 0; i < sz; ++i) {
+        K k{};
+        V v{};
+        is >> k >> v;
+        m[k] = v;
+    }
+    return is;
+}
+template<typename T>
+IOStream& operator<< (IOStream& os, const std::vector<T> &ts) {
+    const uint32_t sz = static_cast<uint32_t>(ts.size());
+    os << sz;
+    for (auto &&v : ts) os << v;
+    return os;
+}
+template<typename T>
+IIStream& operator>> (IIStream& is, std::vector<T> &ts) {
+    uint32_t sz = 0u;
+    is >> sz;
+    if (sz == 0u) {
+        ts.clear();
+    }
+    else {
+        ts.resize(sz);
+        for (std::size_t i = 0; i < sz; ++i) is >> ts[i];
+    }
+    return is;
+}
+
+namespace detail {
+    // Will be used along with default types if possible in specific cases (compile args, etc)
+    // Note: actual implementation is defined by user
+    template<typename T>
+    struct GAPI_EXPORTS S11N {
+        static void serialize(IOStream &, const T &) {}
+        static T deserialize(IIStream &) { T t; return t; }
+    };
+} // namespace detail
+} // namespace s11n
 } // namespace gapi
 } // namespace cv