From 772d70ae4c8d7f7cb6c9a32dda1c1d026cb3e350 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Thu, 19 Nov 2020 19:20:34 -0700
Subject: [PATCH] use glib event callback to invoke per-thread code every time
 the GUI event loop does stuff

---
 gtk2_ardour/ardour_ui.cc          | 14 ++++++++++++++
 gtk2_ardour/ardour_ui.h           |  2 ++
 gtk2_ardour/main.cc               | 11 ++++++++++-
 libs/gtkmm2ext/gtk_ui.cc          | 12 ++++++++++++
 libs/gtkmm2ext/gtkmm2ext/gtk_ui.h |  4 ++++
 5 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/gtk2_ardour/ardour_ui.cc b/gtk2_ardour/ardour_ui.cc
index 95743f1ca8..93c3c4b345 100644
--- a/gtk2_ardour/ardour_ui.cc
+++ b/gtk2_ardour/ardour_ui.cc
@@ -85,6 +85,8 @@
 #include "pbd/scoped_file_descriptor.h"
 #include "pbd/xml++.h"
 
+#include "temporal/superclock.h"
+
 #include "gtkmm2ext/application.h"
 #include "gtkmm2ext/bindings.h"
 #include "gtkmm2ext/gtk_ui.h"
@@ -3111,3 +3113,15 @@ ARDOUR_UI::setup_toplevel_window (Gtk::Window& window, const string& name, void*
 	window.signal_key_press_event().connect (sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::key_event_handler), &window), false);
 	window.signal_key_release_event().connect (sigc::bind (sigc::mem_fun (*this, &ARDOUR_UI::key_event_handler), &window), false);
 }
+
+void
+ARDOUR_UI::event_loop_precall ()
+{
+	std::cout << "ev precall\n";
+
+	if (_session) {
+		Temporal::_thread_sample_rate = _session->sample_rate ();
+	} else {
+		Temporal::_thread_sample_rate = 44100;
+	}
+}
diff --git a/gtk2_ardour/ardour_ui.h b/gtk2_ardour/ardour_ui.h
index d2f30c4233..cccf2ddeb3 100644
--- a/gtk2_ardour/ardour_ui.h
+++ b/gtk2_ardour/ardour_ui.h
@@ -408,6 +408,8 @@ protected:
 	void toggle_rc_options_window ();
 	void toggle_session_options_window ();
 
+	void event_loop_precall ();
+
 private:
 
 	Gtk::Window   _main_window;
diff --git a/gtk2_ardour/main.cc b/gtk2_ardour/main.cc
index 22153530ef..6353d742dc 100644
--- a/gtk2_ardour/main.cc
+++ b/gtk2_ardour/main.cc
@@ -48,6 +48,8 @@
 #include "pbd/boost_debug.h"
 #endif
 
+#include "temporal/superclock.h"
+
 #include "ardour/revision.h"
 #include "ardour/ardour.h"
 #include "ardour/audioengine.h"
@@ -383,7 +385,14 @@ int main (int argc, char *argv[])
 	SetErrorMode (prev_error_mode);
 #endif
 
-	if (!ARDOUR::init (ARDOUR_COMMAND_LINE::try_hw_optimization, localedir.c_str(), true)) {
+	/* this is the GUI thread. Normally this will be done by
+	 * Gtkmm2ext::UI::event_loop_precall() but we need to make sure that
+	 * things are set up for this thread before we get started
+	 */
+
+	Temporal::_thread_sample_rate = 44100;
+
+	if (!ARDOUR::init (ARDOUR_COMMAND_LINE::use_vst, ARDOUR_COMMAND_LINE::try_hw_optimization, localedir.c_str(), true)) {
 		error << string_compose (_("could not initialize %1."), PROGRAM_NAME) << endmsg;
 		Gtk::Main main (argc, argv);
 		Gtk::MessageDialog msg (string_compose (_("Could not initialize %1 (likely due to corrupt config files).\n"
diff --git a/libs/gtkmm2ext/gtk_ui.cc b/libs/gtkmm2ext/gtk_ui.cc
index d3335e3476..b7fa23d1d3 100644
--- a/libs/gtkmm2ext/gtk_ui.cc
+++ b/libs/gtkmm2ext/gtk_ui.cc
@@ -73,11 +73,17 @@ BaseUI::RequestType Gtkmm2ext::AddTimeout = BaseUI::new_request_type();
 
 template class AbstractUI<Gtkmm2ext::UIRequest>;
 
+void
+UI::event_loop_precall ()
+{
+}
+
 UI::UI (string application_name, string thread_name, int *argc, char ***argv)
 	: AbstractUI<UIRequest> (thread_name)
 	, _receiver (*this)
 	, global_bindings (0)
 	, errors (0)
+	, event_callback (boost::bind (&UI::event_loop_precall, this))
 {
 	theMain = new Main (argc, argv);
 
@@ -111,6 +117,12 @@ UI::UI (string application_name, string thread_name, int *argc, char ***argv)
 
 	EventLoop::register_request_buffer_factory ("gui", request_buffer_factory);
 
+	/*
+	 * every time the main loop runs (i.e. before any actual event handling
+	 */
+
+	event_callback.attach (MainContext::get_default());
+
 	/* attach our request source to the default main context */
 
 	attach_request_source ();
diff --git a/libs/gtkmm2ext/gtkmm2ext/gtk_ui.h b/libs/gtkmm2ext/gtkmm2ext/gtk_ui.h
index a9938026f0..cc38766d54 100644
--- a/libs/gtkmm2ext/gtkmm2ext/gtk_ui.h
+++ b/libs/gtkmm2ext/gtkmm2ext/gtk_ui.h
@@ -50,6 +50,7 @@
 #define ABSTRACT_UI_EXPORTS
 #endif
 #include "pbd/abstract_ui.h"
+#include "pbd/glib_event_source.h"
 #include "pbd/ringbufferNPT.h"
 #include "pbd/pool.h"
 #include "pbd/error.h"
@@ -170,6 +171,8 @@ protected:
 			Glib::RefPtr<Gtk::TextBuffer::Tag> ptag, Glib::RefPtr<Gtk::TextBuffer::Tag> mtag,
 			const char *msg);
 
+	virtual void event_loop_precall ();
+
 private:
 	static UI *theGtkUI;
 
@@ -203,6 +206,7 @@ private:
 
 	void do_request (UIRequest*);
 
+	GlibEventLoopCallback event_callback;
 };
 
 } /* namespace */