Clean up is_instrument vs needs-midi-in API

The latter is only really relevant for Audio Units.

This fixes an issue with vocoders or audio-plugins that simply have
a MIDI input for other purposes to be wrongly categorized as Instruments..
.. and thereby override strict-i/o rules (prefer stereo)

4 files changed, 14 insertions, 8 deletions

diff --git a/libs/ardour/ardour/plugin.h b/libs/ardour/ardour/plugin.h
index df4b512ef7..09cd066527 100644
--- a/libs/ardour/ardour/plugin.h
+++ b/libs/ardour/ardour/plugin.h
@@ -395,7 +395,7 @@ class LIBARDOUR_API PluginInfo {
 
 	virtual PluginPtr load (Session& session) = 0;
 	virtual bool is_instrument() const;
-	virtual bool needs_midi_input() const { return is_instrument (); }
+	virtual bool needs_midi_input() const;
 	virtual bool in_category (const std::string &) const { return false; }
 
 	virtual std::vector<Plugin::PresetRecord> get_presets (bool user_only) const = 0;
diff --git a/libs/ardour/ardour/plugin_insert.h b/libs/ardour/ardour/plugin_insert.h
index d38523a77d..a9a2ce6273 100644
--- a/libs/ardour/ardour/plugin_insert.h
+++ b/libs/ardour/ardour/plugin_insert.h
@@ -171,7 +171,7 @@ class LIBARDOUR_API PluginInsert : public Processor
 
 	bool has_no_inputs() const;
 	bool has_no_audio_inputs() const;
-	bool needs_midi_input() const;
+	bool is_instrument () const;
 	bool has_output_presets (
 			ChanCount in = ChanCount (DataType::MIDI, 1),
 			ChanCount out = ChanCount (DataType::AUDIO, 2)
diff --git a/libs/ardour/plugin.cc b/libs/ardour/plugin.cc
index 7d04c3f5d7..f76f96af7a 100644
--- a/libs/ardour/plugin.cc
+++ b/libs/ardour/plugin.cc
@@ -82,9 +82,15 @@ static bool seen_set_state_message = false;
 PBD::Signal2<void, std::string, Plugin*> Plugin::PresetsChanged;
 
 bool
+PluginInfo::needs_midi_input () const
+{
+	return (n_inputs.n_midi() != 0);
+}
+
+bool
 PluginInfo::is_instrument () const
 {
-	return (n_inputs.n_midi() != 0) && (n_outputs.n_audio() > 0);
+	return (n_inputs.n_midi() != 0) && (n_outputs.n_audio() > 0) && (n_inputs.n_audio() == 0);
 }
 
 Plugin::Plugin (AudioEngine& e, Session& s)
diff --git a/libs/ardour/plugin_insert.cc b/libs/ardour/plugin_insert.cc
index 7b3aa60ba4..c3dae8b71f 100644
--- a/libs/ardour/plugin_insert.cc
+++ b/libs/ardour/plugin_insert.cc
@@ -394,13 +394,13 @@ PluginInsert::plugin_latency () const {
 }
 
 bool
-PluginInsert::needs_midi_input() const
+PluginInsert::is_instrument() const
 {
 	PluginInfoPtr pip = _plugins[0]->get_info();
-	if (pip->needs_midi_input ()) {
+	if (pip->is_instrument ()) {
 		return true;
 	}
-	return pip->n_inputs.n_midi() != 0 && pip->n_outputs.n_audio() != 0;
+	return pip->n_inputs.n_midi () != 0 && pip->n_outputs.n_audio () > 0 && pip->n_inputs.n_audio () == 0;
 }
 
 bool
@@ -426,7 +426,7 @@ PluginInsert::has_output_presets (ChanCount in, ChanCount out)
 			return false;
 		}
 	}
-	if (!needs_midi_input ()) {
+	if (!is_instrument ()) {
 			return false;
 	}
 	return true;
@@ -1994,7 +1994,7 @@ PluginInsert::internal_can_support_io_configuration (ChanCount const & inx, Chan
 		m.strict_io = true;
 
 		/* special case MIDI instruments */
-		if (needs_midi_input ()) {
+		if (is_instrument ()) {
 			// output = midi-bypass + at most master-out channels.
 			ChanCount max_out (DataType::AUDIO, 2); // TODO use master-out
 			max_out.set (DataType::MIDI, out.get(DataType::MIDI));