From 174194ebd2df2795b516bee906b04efe0c5f59bc Mon Sep 17 00:00:00 2001
From: Jean Pierre Cimalando <jp-dev@inbox.ru>
Date: Fri, 4 Sep 2020 10:30:03 +0200
Subject: [PATCH] Fix a plugin crash on closing UI

---
 lv2/sfizz_ui.cpp       | 13 +++---
 lv2/vstgui_helpers.cpp | 90 +++++++++++++++++++-----------------------
 lv2/vstgui_helpers.h   | 18 ++++++++-
 3 files changed, 63 insertions(+), 58 deletions(-)

diff --git a/lv2/sfizz_ui.cpp b/lv2/sfizz_ui.cpp
index 020f5989..10ed2cbe 100644
--- a/lv2/sfizz_ui.cpp
+++ b/lv2/sfizz_ui.cpp
@@ -74,6 +74,12 @@ typedef std::unique_ptr<CFrame, FrameHolderDeleter> FrameHolder;
 
 ///
 struct sfizz_ui_t : EditorController, VSTGUIEditorInterface {
+#if LINUX
+    SoHandleInitializer soHandleInitializer;
+#endif
+#if MAC
+    BundleRefInitializer bundleRefInitializer;
+#endif
     LV2UI_Write_Function write = nullptr;
     LV2UI_Controller con = nullptr;
     LV2_URID_Map *map = nullptr;
@@ -369,13 +375,6 @@ LV2_SYMBOL_EXPORT
 const LV2UI_Descriptor *
 lv2ui_descriptor(uint32_t index)
 {
-#if LINUX
-   VSTGUI::initializeSoHandle();
-#endif
-#if MAC
-   VSTGUI::initializeBundleRef();
-#endif
-
     switch (index)
     {
     case 0:
diff --git a/lv2/vstgui_helpers.cpp b/lv2/vstgui_helpers.cpp
index d1ad3187..0a402a20 100644
--- a/lv2/vstgui_helpers.cpp
+++ b/lv2/vstgui_helpers.cpp
@@ -11,6 +11,7 @@
 #include <algorithm>
 #include <memory>
 #include <mutex>
+#include <stdexcept>
 #if LINUX
 #include <dlfcn.h>
 #include <poll.h>
@@ -143,36 +144,31 @@ namespace VSTGUI
 {
 void* soHandle = nullptr;
 
-static volatile bool soHandleInitialized = false;
+static volatile size_t soHandleCount = 0;
 static std::mutex soHandleMutex;
 
-struct Dl_handle_deleter
+SoHandleInitializer::SoHandleInitializer()
 {
-   void operator()(void* x) const noexcept
-   {
-      dlclose(x);
-   }
-};
-static std::unique_ptr<void, Dl_handle_deleter> soHandlePointer;
-} // namespace VSTGUI
-
-void VSTGUI::initializeSoHandle()
-{
-   if (VSTGUI::soHandleInitialized)
-      return;
-
-   std::lock_guard<std::mutex> lock(VSTGUI::soHandleMutex);
-   if (VSTGUI::soHandleInitialized)
-      return;
-
-   Dl_info info;
-   if (dladdr((void*)&lv2ui_descriptor, &info))
-   {
-      VSTGUI::soHandle = dlopen(info.dli_fname, RTLD_LAZY);
-      VSTGUI::soHandlePointer.reset(VSTGUI::soHandle);
-   }
-   VSTGUI::soHandleInitialized = true;
+    std::lock_guard<std::mutex> lock(soHandleMutex);
+    if (soHandleCount++ == 0) {
+        Dl_info info;
+        if (dladdr((void*)&lv2ui_descriptor, &info))
+            soHandle = dlopen(info.dli_fname, RTLD_LAZY);
+        if (!soHandle)
+            throw std::runtime_error("SoHandleInitializer");
+    }
 }
+
+SoHandleInitializer::~SoHandleInitializer()
+{
+    std::lock_guard<std::mutex> lock(soHandleMutex);
+    if (--soHandleCount == 0) {
+        dlclose(soHandle);
+        soHandle = nullptr;
+    }
+}
+
+} // namespace VSTGUI
 #endif
 
 ///
@@ -194,31 +190,27 @@ namespace VSTGUI
 {
 void* gBundleRef = nullptr;
 
-static volatile bool gBundleRefInitialized = false;
+static volatile size_t gBundleRefCount = 0;
 static std::mutex gBundleRefMutex;
 
-struct CFBundle_deleter {
-    void operator()(CFBundleRef x) const noexcept
-    {
-        CFRelease(x);
-    }
-};
-static std::unique_ptr<__CFBundle, CFBundle_deleter> gBundleRefPointer;
-} // namespace VSTGUI
-
-void VSTGUI::initializeBundleRef()
+BundleRefInitializer::BundleRefInitializer()
 {
-   if (VSTGUI::gBundleRefInitialized)
-      return;
-
-   std::lock_guard<std::mutex> lock(VSTGUI::gBundleRefMutex);
-   if (VSTGUI::gBundleRefInitialized)
-      return;
-
-   CFBundleRef bundleRef = GetPluginBundle();
-   VSTGUI::gBundleRef = bundleRef;
-   VSTGUI::gBundleRefPointer.reset(bundleRef);
-
-   VSTGUI::gBundleRefInitialized = true;
+    std::lock_guard<std::mutex> lock(gBundleRefMutex);
+    if (bundleRefCount++ == 0) {
+        gBundleRef = GetPluginBundle();
+        if (!gBundleRef)
+            throw std::runtime_error("BundleRefInitializer");
+    }
 }
+
+BundleRefInitializer::~BundleRefInitializer()
+{
+    std::lock_guard<std::mutex> lock(gBundleRefMutex);
+    if (--bundleRefCount == 0) {
+        CFRelease((CFBundleRef)gBundleRef);
+        gBundleRef = nullptr;
+    }
+}
+
+} // namespace VSTGUI
 #endif
diff --git a/lv2/vstgui_helpers.h b/lv2/vstgui_helpers.h
index 8367a2c4..2fbcd841 100644
--- a/lv2/vstgui_helpers.h
+++ b/lv2/vstgui_helpers.h
@@ -63,13 +63,27 @@ private:
 #if LINUX
 namespace VSTGUI
 {
-void initializeSoHandle();
+class SoHandleInitializer {
+public:
+    SoHandleInitializer();
+    ~SoHandleInitializer();
+private:
+    SoHandleInitializer(const SoHandleInitializer&) = delete;
+    SoHandleInitializer& operator=(const SoHandleInitializer&) = delete;
+};
 }
 #endif
 
 #if MAC
 namespace VSTGUI
 {
-void initializeBundleRef();
+class BundleRefInitializer {
+public:
+    BundleRefInitializer();
+    ~BundleRefInitializer();
+private:
+    BundleRefInitializer(const BundleRefInitializer&) = delete;
+    BundleRefInitializer& operator=(const BundleRefInitializer&) = delete;
+};
 }
 #endif