core(parallel): plugins support

modules/core/src/utils/filesystem.cpp

@@ -587,3 +587,8 @@ cv::String getCacheDirectory(const char* /*sub_directory_name*/, const char* /*c
 #endif // OPENCV_HAVE_FILESYSTEM_SUPPORT
 
 }}} // namespace
+
+
+#if OPENCV_HAVE_FILESYSTEM_SUPPORT
+#include "plugin_loader.impl.hpp"
+#endif

modules/core/src/utils/plugin_loader.impl.hpp

@@ -0,0 +1,80 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+
+//
+// Not a standalone header, part of filesystem.cpp
+//
+
+#include "opencv2/core/utils/plugin_loader.private.hpp"
+
+#if !OPENCV_HAVE_FILESYSTEM_SUPPORT
+#error "Invalid build configuration"
+#endif
+
+#if 0  // TODO
+#ifdef NDEBUG
+#define CV_LOG_STRIP_LEVEL CV_LOG_LEVEL_DEBUG + 1
+#else
+#define CV_LOG_STRIP_LEVEL CV_LOG_LEVEL_VERBOSE + 1
+#endif
+#include <opencv2/core/utils/logger.hpp>
+#endif
+
+namespace cv { namespace plugin { namespace impl {
+
+DynamicLib::DynamicLib(const FileSystemPath_t& filename)
+    : handle(0), fname(filename), disableAutoUnloading_(false)
+{
+    libraryLoad(filename);
+}
+
+DynamicLib::~DynamicLib()
+{
+    if (!disableAutoUnloading_)
+    {
+        libraryRelease();
+    }
+    else if (handle)
+    {
+        CV_LOG_INFO(NULL, "skip auto unloading (disabled): " << toPrintablePath(fname));
+        handle = 0;
+    }
+}
+
+void* DynamicLib::getSymbol(const char* symbolName) const
+{
+    if (!handle)
+    {
+        return 0;
+    }
+    void* res = getSymbol_(handle, symbolName);
+    if (!res)
+    {
+        CV_LOG_DEBUG(NULL, "No symbol '" << symbolName << "' in " << toPrintablePath(fname));
+    }
+    return res;
+}
+
+const std::string DynamicLib::getName() const
+{
+    return toPrintablePath(fname);
+}
+
+void DynamicLib::libraryLoad(const FileSystemPath_t& filename)
+{
+    handle = libraryLoad_(filename);
+    CV_LOG_INFO(NULL, "load " << toPrintablePath(filename) << " => " << (handle ? "OK" : "FAILED"));
+}
+
+void DynamicLib::libraryRelease()
+{
+    if (handle)
+    {
+        CV_LOG_INFO(NULL, "unload "<< toPrintablePath(fname));
+        libraryRelease_(handle);
+        handle = 0;
+    }
+}
+
+}}}  // namespace