Handle X11 events within the Win32 event loop

This unifies event handling and it allows X11 events to still be
processed even when the event loop is blocked.

src/wine-host/bridges/common.cpp

@@ -31,7 +31,7 @@ HostBridge::HostBridge(MainContext& main_context,
 
 HostBridge::~HostBridge() noexcept {}
 
-void HostBridge::handle_win32_events() noexcept {
+void HostBridge::handle_events() noexcept {
     MSG msg;
 
     for (int i = 0;

src/wine-host/bridges/common.h

@@ -67,17 +67,14 @@ class HostBridge {
     virtual void run() = 0;
 
     /**
-     * Handle X11 events for the editor window if it is open. This can safely be
-     * run from any thread.
-     */
-    virtual void handle_x11_events() = 0;
-
-    /**
-     * Run the message loop for this plugin. This is only used for the
-     * individual plugin host, so that we can filter out some unnecessary timer
-     * events. When hosting multiple plugins, a simple central message loop
-     * should be used instead. This is run on a timer in the same IO context as
-     * the one that handles the events, i.e. `main_context`.
+     * Run the message loop for this plugin. This should be called from a timer.
+     * X11 events for the open editors are also handled in this same way,
+     * because they are run from a Win32 timer. This lets us still process those
+     * events even when the Win32 event loop blocks the GUI thread. Since this
+     * function doesn't have any per-plugin behavior, only a single invocation
+     * of this is needed when hosting multiple plugins. This is run on a timer
+     * in the same IO context as the one that handles the events, i.e.
+     * `main_context`.
      *
      * Because of the way the Win32 API works we have to process events on the
      * same thread as the one the window was created on, and that thread is the
@@ -88,7 +85,7 @@ class HostBridge {
      * because of incorrect assumptions made by the plugin. See the dostring for
      * `Vst2Bridge::editor` for more information.
      */
-    void handle_win32_events() noexcept;
+    static void handle_events() noexcept;
 
     /**
      * Used as part of the watchdog. This will check whether the remote host

src/wine-host/bridges/group.cpp

@@ -264,31 +264,17 @@ void GroupBridge::accept_requests() {
 void GroupBridge::async_handle_events() {
     main_context.async_handle_events(
         [&]() {
-            {
-                // Always handle X11 events
-                std::lock_guard lock(active_plugins_mutex);
-                for (auto& [parameters, value] : active_plugins) {
-                    auto& [thread, bridge] = value;
-                    bridge->handle_x11_events();
-                }
-            }
-
             std::lock_guard lock(active_plugins_mutex);
 
-            MSG msg;
-
-            // Keep the loop responsive by not handling too many events at once
+            // Keep the loop responsive by not handling too many events at once.
+            // All X11 events are handled from a Win32 timer so they'll still be
+            // handled even when the GUI is blocked.
             //
             // For some reason the Melda plugins run into a seemingly infinite
             // timer loop for a little while after opening a second editor.
             // Without this limit everything will get blocked indefinitely. How
             // could this be fixed?
-            for (int i = 0; i < max_win32_messages &&
-                            PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE);
-                 i++) {
-                TranslateMessage(&msg);
-                DispatchMessage(&msg);
-            }
+            HostBridge::handle_events();
         },
         [&]() { return !is_event_loop_inhibited(); });
 }

src/wine-host/bridges/vst2.cpp

@@ -492,12 +492,6 @@ void Vst2Bridge::run() {
         });
 }
 
-void Vst2Bridge::handle_x11_events() noexcept {
-    if (editor) {
-        editor->handle_x11_events();
-    }
-}
-
 void Vst2Bridge::close_sockets() {
     sockets.close();
 }

src/wine-host/bridges/vst2.h

@@ -67,8 +67,6 @@ class Vst2Bridge : public HostBridge {
      */
     void run() override;
 
-    void handle_x11_events() noexcept override;
-
    protected:
     void close_sockets() override;
 

src/wine-host/bridges/vst3.cpp

@@ -1190,16 +1190,6 @@ void Vst3Bridge::run() {
         });
 }
 
-void Vst3Bridge::handle_x11_events() noexcept {
-    std::lock_guard lock(object_instances_mutex);
-
-    for (auto& [instance_id, object] : object_instances) {
-        if (object.editor) {
-            object.editor->handle_x11_events();
-        }
-    }
-}
-
 bool Vst3Bridge::maybe_resize_editor(size_t instance_id,
                                      const Steinberg::ViewRect& new_size) {
     Vst3PluginInstance& instance = object_instances.at(instance_id);

src/wine-host/bridges/vst3.h

@@ -290,8 +290,6 @@ class Vst3Bridge : public HostBridge {
      */
     void run() override;
 
-    void handle_x11_events() noexcept override;
-
     /**
      * If the plugin instance has an editor, resize the wrapper window to match
      * the new size. This is called from `IPlugFrame::resizeView()` to make sure