From 40744c672a1db6ca20a1e2a919f3563959217e2f Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sun, 20 Mar 2022 15:41:56 +0100
Subject: [PATCH] Fix VST2 callbacks querying tempo-map

Some VST2 use a custom thread to make callbacks, in this case
the corresponding thread will not have fetched a thread-local
tempo-map.
---
 libs/ardour/session_vst.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libs/ardour/session_vst.cc b/libs/ardour/session_vst.cc
index da76d32888..20505821bf 100644
--- a/libs/ardour/session_vst.cc
+++ b/libs/ardour/session_vst.cc
@@ -75,7 +75,6 @@ intptr_t Session::vst_callback (
 	static VstTimeInfo _timeinfo; // only uses as fallback
 	VstTimeInfo* timeinfo;
 	int32_t newflags = 0;
-	TempoMap::SharedPtr tmap (TempoMap::use());
 
 	if (effect && effect->ptr1) {
 		plug = (VSTPlugin *) (effect->ptr1);
@@ -183,6 +182,7 @@ intptr_t Session::vst_callback (
 		timeinfo->nanoSeconds = g_get_monotonic_time () * 1000;
 
 		if (plug && session) {
+			TempoMap::SharedPtr tmap (TempoMap::fetch());
 			samplepos_t now = plug->transport_sample();
 
 			timeinfo->samplePos = now;
@@ -316,6 +316,7 @@ intptr_t Session::vst_callback (
 		SHOW_CALLBACK ("audioMasterTempoAt");
 		// returns tempo (in bpm * 10000) at sample sample location passed in <value>
 		if (session) {
+			TempoMap::SharedPtr tmap (TempoMap::fetch());
 			const Tempo& t (tmap->metric_at (value).tempo());
 			return t.quarter_notes_per_minute() * 1000;
 		} else {