From 32373dc9570738ddb0f9cf9b00008234142b5f5d Mon Sep 17 00:00:00 2001
From: WeilongWen <81895406+WeilongWen@users.noreply.github.com>
Date: Sun, 27 Oct 2024 20:33:36 +0800
Subject: [PATCH] Keeping the dll path cookie during class instantiation (#147)

---
 include/fmi4cpp/fmi2/fmi2_library.hpp |  4 ++++
 src/fmi4cpp/fmi2/fmi2_library.cpp     | 21 +++++++++++++++++++++
 src/fmi4cpp/library_helper.hpp        | 27 ++-------------------------
 3 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/include/fmi4cpp/fmi2/fmi2_library.hpp b/include/fmi4cpp/fmi2/fmi2_library.hpp
index b09593c..961d379 100644
--- a/include/fmi4cpp/fmi2/fmi2_library.hpp
+++ b/include/fmi4cpp/fmi2/fmi2_library.hpp
@@ -55,6 +55,10 @@ class fmi2_library
 
     fmi2FreeInstanceTYPE* fmi2FreeInstance_;
 
+private:
+#ifdef _WIN32
+    DLL_DIRECTORY_COOKIE dllDirectoryCookie_ = nullptr;
+#endif
 protected:
     fmi2Status lastStatus_;
     DLL_HANDLE handle_ = nullptr;
diff --git a/src/fmi4cpp/fmi2/fmi2_library.cpp b/src/fmi4cpp/fmi2/fmi2_library.cpp
index 62dc382..06f7f87 100644
--- a/src/fmi4cpp/fmi2/fmi2_library.cpp
+++ b/src/fmi4cpp/fmi2/fmi2_library.cpp
@@ -60,6 +60,20 @@ fmi2_library::fmi2_library(const std::string& modelIdentifier, const std::shared
 
     MLOG_DEBUG("Loading shared library '" + std::filesystem::path(libName).stem().string() + get_shared_library_extension() + "'");
 
+#ifdef _WIN32
+    std::string dllDirectory;
+    fmi4cpp::fs::path path(libName);
+
+    if (path.has_parent_path()) {
+        dllDirectory = path.parent_path().string();
+    }
+
+    if (!dllDirectory.empty()) {
+        std::wstring wDllDirectory(dllDirectory.begin(), dllDirectory.end());
+        dllDirectoryCookie_ = AddDllDirectory(wDllDirectory.c_str());
+    }
+#endif
+
     handle_ = load_library(libName);
 
     if (!handle_) {
@@ -419,6 +433,13 @@ void fmi2_library::free_instance(fmi2Component c)
 
 fmi2_library::~fmi2_library()
 {
+#ifdef _WIN32
+    if (dllDirectoryCookie_) {
+        RemoveDllDirectory(dllDirectoryCookie_);
+        dllDirectoryCookie_ = nullptr;
+    }
+#endif
+
     if (handle_) {
         if (!free_library(handle_)) {
             MLOG_ERROR(getLastError());
diff --git a/src/fmi4cpp/library_helper.hpp b/src/fmi4cpp/library_helper.hpp
index e695c7c..e69bbe2 100644
--- a/src/fmi4cpp/library_helper.hpp
+++ b/src/fmi4cpp/library_helper.hpp
@@ -1,10 +1,7 @@
-
 #ifndef FMI4CPP_LIBRARYHELPER_HPP
 #define FMI4CPP_LIBRARYHELPER_HPP
 
 #include <fmi4cpp/dll_handle.hpp>
-
-#include <filesystem>
 #include <sstream>
 
 namespace fmi4cpp
@@ -12,28 +9,8 @@ namespace fmi4cpp
 
 inline DLL_HANDLE load_library(const std::string& libName)
 {
-    std::string dllDirectory;
-
-#ifdef _WIN32
-    std::filesystem::path path(libName);
-    if (path.has_parent_path()) {
-        dllDirectory = path.parent_path().string();
-    }
-
-    DLL_DIRECTORY_COOKIE dllDirectoryCookie = nullptr;
-    if (!dllDirectory.empty()) {
-        std::wstring wDllDirectory(dllDirectory.begin(), dllDirectory.end());
-        dllDirectoryCookie = AddDllDirectory(wDllDirectory.c_str());
-    }
-
-    DLL_HANDLE handle = LoadLibrary(libName.c_str());
-
-    if (dllDirectoryCookie) {
-        RemoveDllDirectory(dllDirectoryCookie);
-    }
-
-    return handle;
-
+#ifdef WIN32
+    return LoadLibrary(libName.c_str());
 #else
     return dlopen(libName.c_str(), RTLD_NOW | RTLD_LOCAL);
 #endif