Expose through backend API hints which plugin UIs are file based

source/backend/CarlaBackend.h

@@ -199,6 +199,11 @@ static const uint PLUGIN_HAS_INLINE_DISPLAY = 0x800;
  */
 static const uint PLUGIN_HAS_CUSTOM_EMBED_UI = 0x1000;
 
+/*!
+ * Plugin custom UI is a fake one that simply invokes an open file browser dialog.
+ */
+static const uint PLUGIN_HAS_CUSTOM_UI_USING_FILE_OPEN = 0x2000;
+
 /** @} */
 
 /* ------------------------------------------------------------------------------------------------------------

source/backend/plugin/CarlaPluginLV2.cpp

@@ -3281,6 +3281,8 @@ public:
 
             if (fUI.type == UI::TYPE_EMBED || fUI.type == UI::TYPE_EXTERNAL)
                 pData->hints |= PLUGIN_NEEDS_UI_MAIN_THREAD;
+            else if (fFilePathURI.isNotEmpty())
+                pData->hints |= PLUGIN_HAS_CUSTOM_UI_USING_FILE_OPEN;
         }
 
         if (LV2_IS_GENERATOR(fRdfDescriptor->Type[0], fRdfDescriptor->Type[1]))

source/backend/plugin/CarlaPluginNative.cpp

@@ -1433,6 +1433,8 @@ public:
             pData->hints |= PLUGIN_NEEDS_FIXED_BUFFERS;
         if (fDescriptor->hints & NATIVE_PLUGIN_NEEDS_UI_MAIN_THREAD)
             pData->hints |= PLUGIN_NEEDS_UI_MAIN_THREAD;
+        if (fDescriptor->hints & NATIVE_PLUGIN_NEEDS_UI_OPEN_SAVE)
+            pData->hints |= PLUGIN_HAS_CUSTOM_UI_USING_FILE_OPEN;
         if (fDescriptor->hints & NATIVE_PLUGIN_USES_MULTI_PROGS)
             pData->hints |= PLUGIN_USES_MULTI_PROGS;
         if (fDescriptor->hints & NATIVE_PLUGIN_HAS_INLINE_DISPLAY)