From c0697099398e19ebe1bce619a0d06786aca5ae3a Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Fri, 2 Oct 2020 16:45:49 +0200
Subject: [PATCH] VST3: do not create persistent view to test has_editor()

This is a better variant of 05d2a0f4a4816d. Mainly becuase
some plugins crash when view->remove() is called for a
view that was never attached.
---
 libs/ardour/ardour/vst3_plugin.h |  3 ++
 libs/ardour/vst3_plugin.cc       | 63 ++++++++++++++++++++++----------
 2 files changed, 46 insertions(+), 20 deletions(-)

diff --git a/libs/ardour/ardour/vst3_plugin.h b/libs/ardour/ardour/vst3_plugin.h
index 11431eb06d..70ebe85455 100644
--- a/libs/ardour/ardour/vst3_plugin.h
+++ b/libs/ardour/ardour/vst3_plugin.h
@@ -77,6 +77,7 @@ public:
 	tresult PLUGIN_API resizeView (IPlugView* view, ViewRect* newSize) SMTG_OVERRIDE;
 
 	/* GUI */
+	bool has_editor () const;
 	IPlugView* view ();
 	void close_view ();
 	PBD::Signal2<void, int, int> OnResizeView;
@@ -152,6 +153,8 @@ private:
 
 	void terminate ();
 
+	IPlugView* try_create_view () const;
+
 	bool connect_components ();
 	bool disconnect_components ();
 
diff --git a/libs/ardour/vst3_plugin.cc b/libs/ardour/vst3_plugin.cc
index 32c37a8fea..39ce623c53 100644
--- a/libs/ardour/vst3_plugin.cc
+++ b/libs/ardour/vst3_plugin.cc
@@ -226,17 +226,7 @@ VST3Plugin::possible_output () const
 bool
 VST3Plugin::has_editor () const
 {
-	IPlugView* view = const_cast<VST3PI*>(_plug)->view ();
-	if (view){
-#ifdef PLATFORM_WINDOWS
-		return kResultOk == view->isPlatformTypeSupported ("HWND");
-#elif defined (__APPLE__)
-		return kResultOk == view->isPlatformTypeSupported ("NSView");
-#else
-		return kResultOk == view->isPlatformTypeSupported ("X11EmbedWindowID");
-#endif
-	}
-	return false;
+	return _plug->has_editor ();
 }
 
 Steinberg::IPlugView*
@@ -1106,8 +1096,7 @@ VST3PI::unit_data ()
 void
 VST3PI::terminate ()
 {
-	close_view ();
-
+	assert (!_view);
 	/* disable all MIDI busses */
 	set_event_bus_state (false);
 
@@ -2209,17 +2198,27 @@ VST3PI::save_state (RAMStream& stream)
  * GUI
  */
 
+IPlugView*
+VST3PI::try_create_view () const
+{
+	IPlugView* view = _controller->createView (Vst::ViewType::kEditor);
+	if (!view) {
+		view = _controller->createView (0);
+	}
+	if (!view) {
+		view = FUnknownPtr<IPlugView> (_controller);
+		if (view) {
+			view->addRef ();
+		}
+	}
+	return view;
+}
+
 IPlugView*
 VST3PI::view ()
 {
 	if (!_view) {
-		_view = _controller->createView (Vst::ViewType::kEditor);
-		if (!_view) {
-			_view = _controller->createView (0);
-		}
-		if (!_view) {
-			_view = FUnknownPtr<IPlugView> (_controller);
-		}
+		_view = try_create_view ();
 		if (_view) {
 			_view->setFrame (this);
 		}
@@ -2239,6 +2238,30 @@ VST3PI::close_view ()
 	_view = 0;
 }
 
+bool
+VST3PI::has_editor () const
+{
+	IPlugView* view = _view;
+	if (!view){
+		view = try_create_view ();
+	}
+
+	bool rv = false;
+	if (view) {
+#ifdef PLATFORM_WINDOWS
+		rv = kResultOk == view->isPlatformTypeSupported (kPlatformTypeHWND);
+#elif defined (__APPLE__)
+		rv = kResultOk == view->isPlatformTypeSupported (kPlatformTypeNSView);
+#else
+		rv = kResultOk == view->isPlatformTypeSupported (kPlatformTypeX11EmbedWindowID);
+#endif
+		if (!_view) {
+			view->release ();
+		}
+	}
+	return rv;
+}
+
 #if SMTG_OS_LINUX
 void
 VST3PI::set_runloop (Linux::IRunLoop* run_loop)