libjack: catch window close when possible, and hide it instead

source/backend/plugin/CarlaPluginJack.cpp

@@ -1182,11 +1182,7 @@ public:
                 break;
 
             case kPluginBridgeNonRtServerUiClosed:
-                carla_stdout("got kPluginBridgeNonRtServerUiClosed, bridge closed cleanly?");
                 pData->engine->callback(ENGINE_CALLBACK_UI_STATE_CHANGED, pData->id, 0, 0, 0.0f, nullptr);
-                //fBridgeThread.signalThreadShouldExit();
-                //handleProcessStopped();
-                //fBridgeThread.stopThread(5000);
                 break;
 
             case kPluginBridgeNonRtServerError: {

source/interposer/interposer-jack-x11.cpp

@@ -58,6 +58,7 @@ struct ScopedLibOpen {
 // Function typedefs
 
 typedef int (*XWindowFunc)(Display*, Window);
+typedef int (*XNextEventFunc)(Display*, XEvent*);
 typedef int (*CarlaInterposedCallback)(int, void*);
 
 // --------------------------------------------------------------------------------------------------------------------
@@ -107,6 +108,14 @@ static int real_XUnmapWindow(Display* display, Window window)
     return func(display, window);
 }
 
+static int real_XNextEvent(Display* display, XEvent* event)
+{
+    static const XNextEventFunc func = (XNextEventFunc)::dlsym(RTLD_NEXT, "XNextEvent");
+    CARLA_SAFE_ASSERT_RETURN(func != nullptr, 0);
+
+    return func(display, event);
+}
+
 // --------------------------------------------------------------------------------------------------------------------
 // Custom carla window handling
 
@@ -292,6 +301,39 @@ int XUnmapWindow(Display* display, Window window)
     return real_XUnmapWindow(display, window);
 }
 
+CARLA_EXPORT
+int XNextEvent(Display* display, XEvent* event)
+{
+    const int ret = real_XNextEvent(display, event);
+
+    if (ret != 0)
+        return ret;
+    if (gCurrentlyMappedWindow == 0)
+        return ret;
+    if (event->type != ClientMessage)
+        return ret;
+    if (event->xclient.window != gCurrentlyMappedWindow)
+        return ret;
+
+    char* const type = XGetAtomName(display, event->xclient.message_type);
+    CARLA_SAFE_ASSERT_RETURN(type != nullptr, 0);
+
+    if (std::strcmp(type, "WM_PROTOCOLS") != 0)
+        return ret;
+    if (event->xclient.data.l[0] != XInternAtom(display, "WM_DELETE_WINDOW", False))
+        return ret;
+
+    gCurrentWindowVisible = false;
+    gCurrentWindowMapped = false;
+
+    if (gInterposedCallback != nullptr)
+        gInterposedCallback(1, nullptr);
+
+    event->type = 0;
+    carla_stdout("XNextEvent close event catched, hiding UI instead");
+    return real_XUnmapWindow(display, gCurrentlyMappedWindow);
+}
+
 // --------------------------------------------------------------------------------------------------------------------
 // Full control helper
 

source/libjack/libjack.cpp

@@ -242,7 +242,7 @@ public:
 
     int handleInterposerCallback(const int cb_action, void* const ptr)
     {
-        carla_stdout("handleInterposerCallback(%o, %p)", cb_action, ptr);
+        carla_debug("handleInterposerCallback(%o, %p)", cb_action, ptr);
 
         switch (cb_action)
         {
@@ -255,6 +255,9 @@ public:
         }
 
         return 0;
+
+        // maybe unused
+        (void)ptr;
     }
 
     // -------------------------------------------------------------------