Clean up Latency API (Processor vs Plugin)

Plugins are only a source of Latency (Plugin delay).
The API to query, signal and override Latency is managed
by PluginInsert.

libs/ardour/ardour/audio_unit.h

@@ -70,7 +70,6 @@ class LIBARDOUR_API AUPlugin : public ARDOUR::Plugin
 	const char * maker () const { return _info->creator.c_str(); }
 	uint32_t parameter_count () const;
 	float default_value (uint32_t port);
-	samplecnt_t signal_latency() const;
 	void set_parameter (uint32_t which, float val);
 	float get_parameter (uint32_t which) const;
 
@@ -161,6 +160,7 @@ class LIBARDOUR_API AUPlugin : public ARDOUR::Plugin
 	void do_remove_preset (std::string);
 
   private:
+	samplecnt_t plugin_latency() const;
 	void find_presets ();
 
 	boost::shared_ptr<CAComponent> comp;

libs/ardour/ardour/ladspa_plugin.h

@@ -50,7 +50,6 @@ class LIBARDOUR_API LadspaPlugin : public ARDOUR::Plugin
 	const char* maker() const           { return _descriptor->Maker; }
 	uint32_t    parameter_count() const { return _descriptor->PortCount; }
 	float       default_value (uint32_t port) { return _default_value (port); }
-	samplecnt_t  signal_latency() const;
 	void        set_parameter (uint32_t port, float val);
 	float       get_parameter (uint32_t port) const;
 	int         get_parameter_descriptor (uint32_t which, ParameterDescriptor&) const;
@@ -132,6 +131,7 @@ class LIBARDOUR_API LadspaPlugin : public ARDOUR::Plugin
 	uint32_t                 _index;
 	bool                     _was_activated;
 
+	samplecnt_t plugin_latency() const;
 	void find_presets ();
 
 	void init (std::string module_path, uint32_t index, samplecnt_t rate);

libs/ardour/ardour/latent.h

@@ -25,12 +25,18 @@
 
 namespace ARDOUR {
 
-class LIBARDOUR_API Latent {
+class LIBARDOUR_API HasLatency {
 public:
-	Latent() : _user_latency (0) {}
+	virtual ~HasLatency() {}
+	virtual samplecnt_t signal_latency() const = 0;
+};
+
+class LIBARDOUR_API Latent : public HasLatency {
+public:
+	Latent ();
+	Latent (Latent const&);
 	virtual ~Latent() {}
 
-	virtual samplecnt_t signal_latency() const = 0;
 
 	/* effective latency to be used while processing */
 	samplecnt_t effective_latency() const {
@@ -77,6 +83,7 @@ protected:
 private:
 	samplecnt_t _use_user_latency;
 	samplecnt_t _user_latency;
+
 	static bool _zero_latency;
 };
 

libs/ardour/ardour/luaproc.h

@@ -85,7 +85,6 @@ public:
 	void cleanup () { }
 
 	int set_block_size (pframes_t /*nframes*/) { return 0; }
-	samplecnt_t signal_latency() const { return _signal_latency; }
 
 	int connect_and_run (BufferSet& bufs,
 			samplepos_t start, samplepos_t end, double speed,
@@ -129,6 +128,7 @@ public:
 	LuaTableRef* instance_ref () { return &lref; }
 
 private:
+	samplecnt_t plugin_latency() const { return _signal_latency; }
 	void find_presets ();
 
 	/* END Plugin interface */

libs/ardour/ardour/lv2_plugin.h

@@ -75,7 +75,6 @@ class LIBARDOUR_API LV2Plugin : public ARDOUR::Plugin, public ARDOUR::Workee
 	uint32_t    parameter_count () const;
 	float       default_value (uint32_t port);
 	samplecnt_t  max_latency () const;
-	samplecnt_t  signal_latency () const;
 	void        set_parameter (uint32_t port, float val);
 	float       get_parameter (uint32_t port) const;
 	std::string get_docs() const;
@@ -350,6 +349,8 @@ class LIBARDOUR_API LV2Plugin : public ARDOUR::Plugin, public ARDOUR::Workee
 	bool _midnam_dirty;
 #endif
 
+	samplecnt_t plugin_latency () const;
+
 	void latency_compute_run ();
 	std::string do_save_preset (std::string);
 	void do_remove_preset (std::string);

libs/ardour/ardour/plugin.h

@@ -67,7 +67,7 @@ typedef std::set<uint32_t> PluginOutputConfiguration;
  *
  * Plugins are not used directly in Ardour but always wrapped by a PluginInsert.
  */
-class LIBARDOUR_API Plugin : public PBD::StatefulDestructible, public Latent
+class LIBARDOUR_API Plugin : public PBD::StatefulDestructible, public HasLatency
 {
   public:
 	Plugin (ARDOUR::AudioEngine&, ARDOUR::Session&);
@@ -337,6 +337,10 @@ class LIBARDOUR_API Plugin : public PBD::StatefulDestructible, public Latent
 	PBD::Signal1<void,uint32_t> StartTouch;
 	PBD::Signal1<void,uint32_t> EndTouch;
 
+	samplecnt_t signal_latency () const {
+		return plugin_latency ();
+	}
+
 protected:
 
 	friend class PluginInsert;
@@ -370,6 +374,8 @@ protected:
 
 private:
 
+	virtual samplecnt_t plugin_latency () const = 0;
+
 	/** Fill _presets with our presets */
 	virtual void find_presets () = 0;
 

libs/ardour/ardour/vst_plugin.h

@@ -61,7 +61,6 @@ public:
 	bool load_preset (PresetRecord);
 	int get_parameter_descriptor (uint32_t which, ParameterDescriptor&) const;
 	std::string describe_parameter (Evoral::Parameter);
-	samplecnt_t signal_latency() const;
 	std::set<Evoral::Parameter> automatable() const;
 
 	PBD::Signal0<void> LoadPresetProgram;
@@ -119,6 +118,7 @@ protected:
 	void do_remove_preset (std::string name);
 	XMLTree * presets_tree () const;
 	std::string presets_file () const;
+	samplecnt_t plugin_latency() const;
 	void find_presets ();
 
 	VSTHandle* _handle;

libs/ardour/audio_unit.cc

@@ -954,7 +954,7 @@ AUPlugin::default_value (uint32_t port)
 }
 
 samplecnt_t
-AUPlugin::signal_latency () const
+AUPlugin::plugin_latency () const
 {
 	guint lat = g_atomic_int_get (&_current_latency);;
 	if (lat == UINT_MAX) {

libs/ardour/ladspa_plugin.cc

@@ -526,7 +526,7 @@ LadspaPlugin::describe_parameter (Evoral::Parameter which)
 }
 
 ARDOUR::samplecnt_t
-LadspaPlugin::signal_latency () const
+LadspaPlugin::plugin_latency () const
 {
 	if (_latency_control_port) {
 		return (samplecnt_t) floor (*_latency_control_port);

libs/ardour/latent.cc

@@ -24,6 +24,19 @@ using namespace ARDOUR;
 
 bool ARDOUR::Latent::_zero_latency = false;
 
+Latent::Latent ()
+	: HasLatency ()
+	, _use_user_latency (false)
+	, _user_latency (0)
+{}
+
+Latent::Latent (Latent const& other)
+	: HasLatency ()
+	, _use_user_latency (other._use_user_latency)
+	, _user_latency (other._user_latency)
+{}
+
+
 int
 Latent::set_state (const XMLNode& node, int version)
 {

libs/ardour/lv2_plugin.cc

@@ -2380,7 +2380,7 @@ LV2Plugin::max_latency () const
 }
 
 samplecnt_t
-LV2Plugin::signal_latency() const
+LV2Plugin::plugin_latency() const
 {
 	if (_latency_control_port) {
 		return (samplecnt_t)floor(*_latency_control_port);

libs/ardour/plugin.cc

@@ -102,7 +102,7 @@ Plugin::Plugin (AudioEngine& e, Session& s)
 
 Plugin::Plugin (const Plugin& other)
 	: StatefulDestructible()
-	, Latent()
+	, HasLatency()
 	, _engine (other._engine)
 	, _session (other._session)
 	, _info (other._info)

libs/ardour/vst_plugin.cc

@@ -643,7 +643,7 @@ VSTPlugin::describe_parameter (Evoral::Parameter param)
 }
 
 samplecnt_t
-VSTPlugin::signal_latency () const
+VSTPlugin::plugin_latency () const
 {
 #if ( defined(__x86_64__) || defined(_M_X64) )
 	return *((int32_t *) (((char *) &_plugin->flags) + 24)); /* initialDelay */