From da95a0a0ee2506daca05870d34b8786567edff5b Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Mon, 14 Mar 2022 13:16:55 -0600
Subject: [PATCH] replace sample rate callback used for superclock<=>sample
 conversion

Now using a globally-scoped static variable which is updated by the
AudioEngine whenever an SR change occurs. Defaults to 48kHz and can
be used even before there is a backend.
---
 libs/ardour/ardour/audioengine.h                  | 3 ---
 libs/ardour/audioengine.cc                        | 1 +
 libs/ardour/globals.cc                            | 2 --
 libs/ardour/test/automation_list_property_test.cc | 5 -----
 libs/ardour/test/test_util.cc                     | 2 --
 libs/temporal/superclock.cc                       | 6 +++---
 libs/temporal/temporal/superclock.h               | 6 +++---
 7 files changed, 7 insertions(+), 18 deletions(-)

diff --git a/libs/ardour/ardour/audioengine.h b/libs/ardour/ardour/audioengine.h
index d696238e5a..0f34efe2c2 100644
--- a/libs/ardour/ardour/audioengine.h
+++ b/libs/ardour/ardour/audioengine.h
@@ -199,9 +199,6 @@ class LIBARDOUR_API AudioEngine : public PortManager, public SessionHandlePtr
 	static AudioEngine* instance() { return _instance; }
 	static void destroy();
 
-	/* this method is intended only to be used as a "fast" callback from libtemporal */
-	static int static_sample_rate () { return _instance->sample_rate(); }
-
 	void died ();
 
 	/* The backend will cause these at the appropriate time(s) */
diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index 5d10357583..c36316ee0a 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -198,6 +198,7 @@ AudioEngine::sample_rate_change (pframes_t nframes)
 	}
 
 	SampleRateChanged (nframes); /* EMIT SIGNAL */
+	Temporal::set_sample_rate (nframes);
 
 #ifdef SILENCE_AFTER_SECONDS
 	_silence_countdown = nframes * SILENCE_AFTER_SECONDS;
diff --git a/libs/ardour/globals.cc b/libs/ardour/globals.cc
index 11e75a2804..df472cc9af 100644
--- a/libs/ardour/globals.cc
+++ b/libs/ardour/globals.cc
@@ -529,8 +529,6 @@ ARDOUR::init (bool try_optimization, const char* localedir, bool with_gui)
 		return true;
 	}
 
-	Temporal::set_sample_rate_callback (AudioEngine::static_sample_rate);
-
 	running_from_gui = with_gui;
 
 #ifndef NDEBUG
diff --git a/libs/ardour/test/automation_list_property_test.cc b/libs/ardour/test/automation_list_property_test.cc
index 27d003297f..ae082b3b3f 100644
--- a/libs/ardour/test/automation_list_property_test.cc
+++ b/libs/ardour/test/automation_list_property_test.cc
@@ -43,19 +43,14 @@ write_automation_list_xml (XMLNode* node, std::string filename)
 	CPPUNIT_ASSERT (write_ref (node, output_file));
 }
 
-static int
-static_sample_rate () { return 48000; }
-
 void
 AutomationListPropertyTest::setUp ()
 {
-	Temporal::set_sample_rate_callback (static_sample_rate);
 }
 
 void
 AutomationListPropertyTest::tearDown ()
 {
-	Temporal::set_sample_rate_callback (0);
 }
 
 void
diff --git a/libs/ardour/test/test_util.cc b/libs/ardour/test/test_util.cc
index 91754ceb4a..8b4fba6baf 100644
--- a/libs/ardour/test/test_util.cc
+++ b/libs/ardour/test/test_util.cc
@@ -107,7 +107,6 @@ create_and_start_dummy_backend ()
 	CPPUNIT_ASSERT (engine->set_backend ("None (Dummy)", "Unit-Test", ""));
 
 	CPPUNIT_ASSERT (engine->start () == 0);
-	Temporal::set_sample_rate_callback (AudioEngine::static_sample_rate);
 }
 
 void
@@ -116,7 +115,6 @@ stop_and_destroy_backend ()
 	AudioEngine::instance()->remove_session ();
 	AudioEngine::instance()->stop ();
 	AudioEngine::destroy ();
-	Temporal::set_sample_rate_callback (0);
 }
 
 /** @param dir Session directory.
diff --git a/libs/temporal/superclock.cc b/libs/temporal/superclock.cc
index 8b7062042d..613b971da3 100644
--- a/libs/temporal/superclock.cc
+++ b/libs/temporal/superclock.cc
@@ -22,10 +22,10 @@
 Temporal::superclock_t Temporal::superclock_ticks_per_second = 508032000; // 2^10 * 3^4 * 5^3 * 7^2
 #endif
 
-int (*Temporal::sample_rate_callback)() = 0;
+int Temporal::most_recent_engine_sample_rate = 48000; /* have to pick something as a default */
 
 void
-Temporal::set_sample_rate_callback (int (*func)())
+Temporal::set_sample_rate (int sr)
 {
-	sample_rate_callback = func;
+	most_recent_engine_sample_rate = sr;
 }
diff --git a/libs/temporal/temporal/superclock.h b/libs/temporal/temporal/superclock.h
index 4eb2c02bf3..f03ac2ca6f 100644
--- a/libs/temporal/temporal/superclock.h
+++ b/libs/temporal/temporal/superclock.h
@@ -38,12 +38,12 @@ typedef int64_t superclock_t;
 static inline superclock_t superclock_to_samples (superclock_t s, int sr) { return int_div_round (s * sr, superclock_ticks_per_second); }
 static inline superclock_t samples_to_superclock (int64_t samples, int sr) { return int_div_round (samples * superclock_ticks_per_second, superclock_t (sr)); }
 
-extern int (*sample_rate_callback)();
+extern int most_recent_engine_sample_rate;
 
-LIBTEMPORAL_API void set_sample_rate_callback (int (*function)());
+LIBTEMPORAL_API void set_sample_rate (int sr);
 
 }
 
-#define TEMPORAL_SAMPLE_RATE (sample_rate_callback ())
+#define TEMPORAL_SAMPLE_RATE (most_recent_engine_sample_rate)
 
 #endif /* __ardour_superclock_h__ */