From 0c047f9a66a713bc6d9c860343f833233bb8778c Mon Sep 17 00:00:00 2001
From: Robbert van der Helm <mail@robbertvanderhelm.nl>
Date: Tue, 26 May 2020 17:09:09 +0200
Subject: [PATCH] Work around a memory corruption issue on unload

I'm really not sure what is happening here, and it might just be a
winelib thing.
---
 src/wine-host/bridges/vst2.cpp | 10 ++++++----
 src/wine-host/bridges/vst2.h   | 15 ++++++++++++---
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/src/wine-host/bridges/vst2.cpp b/src/wine-host/bridges/vst2.cpp
index b80688f3..a52683de 100644
--- a/src/wine-host/bridges/vst2.cpp
+++ b/src/wine-host/bridges/vst2.cpp
@@ -67,7 +67,10 @@ Vst2Bridge& get_bridge_instance(const AEffect* plugin) {
 
 Vst2Bridge::Vst2Bridge(std::string plugin_dll_path,
                        std::string socket_endpoint_path)
-    : plugin_handle(LoadLibrary(plugin_dll_path.c_str()), FreeLibrary),
+    // See `plugin_handle`s docstring for information on why we're leaking
+    // memory here
+    // : plugin_handle(LoadLibrary(plugin_dll_path.c_str()), FreeLibrary),
+    : plugin_handle(LoadLibrary(plugin_dll_path.c_str())),
       io_context(),
       socket_endpoint(socket_endpoint_path),
       host_vst_dispatch(io_context),
@@ -85,9 +88,8 @@ Vst2Bridge::Vst2Bridge(std::string plugin_dll_path,
     // there are some older deprecated names that legacy plugins may still use
     VstEntryPoint vst_entry_point = nullptr;
     for (auto name : {"VSTPluginMain", "main_plugin", "main"}) {
-        vst_entry_point =
-            reinterpret_cast<VstEntryPoint>(reinterpret_cast<size_t>(
-                GetProcAddress(plugin_handle.get(), name)));
+        vst_entry_point = reinterpret_cast<VstEntryPoint>(
+            reinterpret_cast<size_t>(GetProcAddress(plugin_handle, name)));
 
         if (vst_entry_point != nullptr) {
             break;
diff --git a/src/wine-host/bridges/vst2.h b/src/wine-host/bridges/vst2.h
index 5abfd252..0622c891 100644
--- a/src/wine-host/bridges/vst2.h
+++ b/src/wine-host/bridges/vst2.h
@@ -165,10 +165,19 @@ class Vst2Bridge {
 
     /**
      * The shared library handle of the VST plugin. I sadly could not get
-     * Boost.DLL to work here, so we'll just load the VST plugisn by hand.
+     * Boost.DLL to work here, so we'll just load the VST plugins by hand.
+     *
+     * FIXME: I don't know why, but `FreeLibrary()` seems to corrupt memory.
+     *        This leads to a lot of weird behavior, such as plugins crashing as
+     *        soon as other plugins get loaded or calls to `LoadLibrary()`
+     *        returning null pointers while they would otherwise load fine
+     *        without the prior call to `FreeLibrary`. We are leaking memory
+     *        here until this is fixed, but it should not be a huge issue since
+     *        this leak only exists for plugin groups.
      */
-    std::unique_ptr<std::remove_pointer_t<HMODULE>, decltype(&FreeLibrary)>
-        plugin_handle;
+    // std::unique_ptr<std::remove_pointer_t<HMODULE>, decltype(&FreeLibrary)>
+    //     plugin_handle;
+    HMODULE plugin_handle;
 
     /**
      * The loaded plugin's `AEffect` struct, obtained using the above library