From 00d1391ed91a182c3f3ff9ab2d3cee2f877bc704 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Fri, 19 Feb 2021 21:47:42 +0100
Subject: [PATCH] Remember version that was used to scan VST plugins

---
 libs/ardour/ardour/plugin_manager.h        |  3 +++
 libs/ardour/ardour/rc_configuration_vars.h |  1 +
 libs/ardour/plugin_manager.cc              | 18 ++++++++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/libs/ardour/ardour/plugin_manager.h b/libs/ardour/ardour/plugin_manager.h
index a9f96279fb..63f32f1a86 100644
--- a/libs/ardour/ardour/plugin_manager.h
+++ b/libs/ardour/ardour/plugin_manager.h
@@ -76,6 +76,9 @@ public:
 	const std::string get_default_windows_vst_path() const { return windows_vst_path; }
 	const std::string get_default_lxvst_path() const { return lxvst_path; }
 
+	static uint32_t cache_version ();
+	bool cache_valid () const;
+
 	/* always return LXVST for any VST subtype */
 	static PluginType to_generic_vst (const PluginType);
 
diff --git a/libs/ardour/ardour/rc_configuration_vars.h b/libs/ardour/ardour/rc_configuration_vars.h
index 7a356a11ac..e7a1f5865e 100644
--- a/libs/ardour/ardour/rc_configuration_vars.h
+++ b/libs/ardour/ardour/rc_configuration_vars.h
@@ -234,6 +234,7 @@ CONFIG_VARIABLE (bool, discover_audio_units, "discover-audio-units", false)
 CONFIG_VARIABLE (bool, ask_replace_instrument, "ask-replace-instrument", true)
 CONFIG_VARIABLE (bool, ask_setup_instrument, "ask-setup-instrument", true)
 CONFIG_VARIABLE (uint32_t, limit_n_automatables, "limit-n-automatables", 512)
+CONFIG_VARIABLE (uint32_t, plugin_cache_version, "plugin-cache-version", 0)
 
 /* custom user plugin paths */
 CONFIG_VARIABLE (std::string, plugin_path_vst, "plugin-path-vst", "@default@")
diff --git a/libs/ardour/plugin_manager.cc b/libs/ardour/plugin_manager.cc
index b196474a42..d77d1a975e 100644
--- a/libs/ardour/plugin_manager.cc
+++ b/libs/ardour/plugin_manager.cc
@@ -324,6 +324,19 @@ PluginManager::~PluginManager()
 	delete _vst3_plugin_info;
 }
 
+bool
+PluginManager::cache_valid () const
+{
+	return Config->get_plugin_cache_version () >= cache_version ();
+}
+
+uint32_t
+PluginManager::cache_version ()
+{
+	/* see ARDOUR::vst3_scan_and_cache  VST3Cache version = +1 */
+	return 1000 * atoi (X_(PROGRAM_VERSION)) + 1;
+}
+
 struct PluginInfoPtrNameSorter {
 	bool operator () (PluginInfoPtr const& a, PluginInfoPtr const& b) const {
 		return PBD::downcase (a->name) < PBD::downcase (b->name);
@@ -520,6 +533,11 @@ PluginManager::refresh (bool cache_only)
 	bool conceal_vst2 = false;
 #endif
 
+	if (!cache_only && !cache_valid ()) {
+		Config->set_plugin_cache_version (cache_version ());
+		Config->save_state();
+	}
+
 #ifdef AUDIOUNIT_SUPPORT
 	if (cache_only) {
 		BootMessage (_("Scanning AU Plugins"));