Ensure gRPC server dll is never unloaded from the process once it is loaded (#143)

* Fix crash while unloading labview-grpc dll

* Ensure gRPC server dll is never unloaded from the process once it is loaded

* Minor cleanup

Author: shivaprasad-basavaraj

CMakeLists.txt

@@ -63,6 +63,7 @@ add_library(labview_grpc_server SHARED
   src/message_element_metadata_owner.cc
   src/any_support.cc
   src/unpacked_fields.cc
+  src/grpc_load.cc
   )
 target_link_libraries(labview_grpc_server
    ${_REFLECTION}

src/grpc_load.cc

@@ -0,0 +1,26 @@
+#ifndef _WIN32
+#include <dlfcn.h>
+#else
+#include <wtypes.h>
+#endif
+
+namespace grpc_labview
+{
+#ifndef _WIN32
+    typedef void* LibHandle;
+#else
+    typedef HMODULE LibHandle;
+#endif
+
+    LibHandle LockgRPCLibraryIntoProcessMem()
+    {
+#if _WIN32
+        auto dllHandle = LoadLibrary("labview_grpc_server.dll");
+#else
+        auto dllHandle = dlopen("liblabview_grpc_server.so", RTLD_LAZY);
+#endif
+        return dllHandle;
+    }
+
+    LibHandle gSelfLibHandle = LockgRPCLibraryIntoProcessMem();
+}