Better driver interface for input/output.

MIDI output (pass-through anyway, plugin->output is still screwy).
Fix crash on failure to instantiate LV2 plugin.


git-svn-id: http://svn.drobilla.net/lad/ingen@786 a436a847-0d15-0410-975c-d299462d15a1

25 files changed, 194 insertions, 65 deletions

diff --git a/src/libs/engine/Connection.cpp b/src/libs/engine/Connection.cpp
index c2ecb2ec..47893acb 100644
--- a/src/libs/engine/Connection.cpp
+++ b/src/libs/engine/Connection.cpp
@@ -51,6 +51,9 @@ Connection::Connection(Port* src_port, Port* dst_port)
 	/*assert((src_port->parent_node()->poly() == dst_port->parent_node()->poly())
 		|| (src_port->parent_node()->poly() == 1 || dst_port->parent_node()->poly() == 1));*/
 
+	if (type() == DataType::MIDI)
+		_must_mix = false; // FIXME: kludge
+
 	if (_must_mix)
 		_local_buffer = BufferFactory::create(dst_port->type(), dst_port->buffer(0)->size());
 
@@ -81,10 +84,11 @@ Connection::set_buffer_size(size_t size)
 void
 Connection::prepare_poly(uint32_t poly)
 {
-	_must_mix = (type() == DataType::FLOAT) && (poly > 1) && (
-			   (_src_port->poly() != _dst_port->poly())
-			|| (_src_port->polyphonic() && !_dst_port->polyphonic())
-			|| (_src_port->parent()->polyphonic() && !_dst_port->parent()->polyphonic()) );
+	if (type() == DataType::FLOAT)
+		_must_mix = (poly > 1) && (
+				   (_src_port->poly() != _dst_port->poly())
+				|| (_src_port->polyphonic() && !_dst_port->polyphonic())
+				|| (_src_port->parent()->polyphonic() && !_dst_port->parent()->polyphonic()) );
 
 	/*cerr << src_port()->path() << " * " << src_port()->poly()
 			<< " -> " << dst_port()->path() << " * " << dst_port()->poly()
@@ -118,19 +122,13 @@ Connection::process(SampleCount nframes, FrameTime start, FrameTime end)
 	 * would avoid having to mix multiple times.  Probably not a very common
 	 * case, but it would be faster anyway. */
 	
-	// FIXME: Implement MIDI mixing
-	
-	if (_must_mix) {
-		assert(type() == DataType::FLOAT);
+	if (_must_mix && type() == DataType::FLOAT) {
 
 		const AudioBuffer* const src_buffer = (AudioBuffer*)src_port()->buffer(0);
 		AudioBuffer*             mix_buf    = (AudioBuffer*)_local_buffer;
 
 		const size_t copy_size = std::min(src_buffer->size(), mix_buf->size());
 
-		/*cerr << "[Connection] Mixing " << src_port()->path() << " * " << src_port()->poly()
-			<< " -> " << dst_port()->path() << " * " << dst_port()->poly() << endl;*/
-
 		// Copy src buffer to start of mix buffer
 		mix_buf->copy((AudioBuffer*)src_port()->buffer(0), 0, copy_size-1);
 
@@ -156,7 +154,13 @@ Connection::process(SampleCount nframes, FrameTime start, FrameTime end)
 		// Scale the buffer down.
 		if (src_port()->poly() > 1)
 			mix_buf->scale(1.0f/(float)src_port()->poly(), 0, _buffer_size-1);
+
+	} else if (_must_mix && type() == DataType::MIDI) {
+
+		cerr << "WARNING: No MIDI mixing." << endl;
+	
 	}
+
 }
 
 
diff --git a/src/libs/engine/DSSINode.hpp b/src/libs/engine/DSSINode.hpp
index 1e24836d..418be920 100644
--- a/src/libs/engine/DSSINode.hpp
+++ b/src/libs/engine/DSSINode.hpp
@@ -54,7 +54,7 @@ public:
 	void configure(const string& key, const string& val);
 	void program(int bank, int program);
 
-	void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 	
 	void set_port_buffer(uint32_t voice, uint32_t port_num, Buffer* buf);
 	
diff --git a/src/libs/engine/DuplexPort.cpp b/src/libs/engine/DuplexPort.cpp
index f0b138ed..6c195e87 100644
--- a/src/libs/engine/DuplexPort.cpp
+++ b/src/libs/engine/DuplexPort.cpp
@@ -54,7 +54,7 @@ DuplexPort::pre_process(SampleCount nframes, FrameTime start, FrameTime end)
 }
 
 void
-DuplexPort::process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end)
+DuplexPort::process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end)
 {
 }
 
@@ -64,9 +64,9 @@ DuplexPort::post_process(SampleCount nframes, FrameTime start, FrameTime end)
 {
 	// Think about it...
 	
-	if (_is_output)
-		InputPort::pre_process(nframes, start, end);
-	else
+//	if (_is_output)
+//		InputPort::pre_process(nframes, start, end);
+//else
 		OutputPort::pre_process(nframes, start, end);
 }
 
diff --git a/src/libs/engine/DuplexPort.hpp b/src/libs/engine/DuplexPort.hpp
index 4c98ea88..c74eca84 100644
--- a/src/libs/engine/DuplexPort.hpp
+++ b/src/libs/engine/DuplexPort.hpp
@@ -45,7 +45,7 @@ public:
 	virtual ~DuplexPort() {}
 
 	void pre_process(SampleCount nframes, FrameTime start, FrameTime end);
-	void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 	void post_process(SampleCount nframes, FrameTime start, FrameTime end);
 	
 	bool is_input()  const { return !_is_output; }
diff --git a/src/libs/engine/GraphObject.hpp b/src/libs/engine/GraphObject.hpp
index 3da9c64f..02bd2bfc 100644
--- a/src/libs/engine/GraphObject.hpp
+++ b/src/libs/engine/GraphObject.hpp
@@ -67,7 +67,7 @@ public:
 	inline GraphObject*  parent() const { return _parent; }
 	inline const string& name()   const { return _name; }
 	
-	virtual void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end) = 0;
+	virtual void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end) = 0;
 
 	/** Rename */
 	virtual void set_path(const Path& new_path) {
diff --git a/src/libs/engine/InputPort.hpp b/src/libs/engine/InputPort.hpp
index 6aa86b9c..a34ef394 100644
--- a/src/libs/engine/InputPort.hpp
+++ b/src/libs/engine/InputPort.hpp
@@ -57,7 +57,7 @@ public:
 	const Connections& connections() { return _connections; }
 
 	void pre_process(SampleCount nframes, FrameTime start, FrameTime end);
-	void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 	void post_process(SampleCount nframes, FrameTime start, FrameTime end);
 	
 	bool is_connected() const { return (_connections.size() > 0); }
diff --git a/src/libs/engine/JackAudioDriver.cpp b/src/libs/engine/JackAudioDriver.cpp
index 4f32beb4..b5748e78 100644
--- a/src/libs/engine/JackAudioDriver.cpp
+++ b/src/libs/engine/JackAudioDriver.cpp
@@ -267,24 +267,25 @@ JackAudioDriver::_process_cb(jack_nframes_t nframes)
 
 	// FIXME: all of this time stuff is screwy
 	
-	static jack_nframes_t start_of_current_cycle = 0;
-	static jack_nframes_t start_of_last_cycle    = 0;
-
 	// FIXME: support nframes != buffer_size, even though that never damn well happens
 	assert(nframes == _buffer_size);
 
 	// Jack can elect to not call this function for a cycle, if overloaded
 	// FIXME: this doesn't make sense, and the start time isn't used anyway
-	start_of_current_cycle = jack_last_frame_time(_client);
-	start_of_last_cycle = start_of_current_cycle - nframes;
+	const jack_nframes_t start_of_current_cycle = jack_last_frame_time(_client);
+	const jack_nframes_t start_of_last_cycle = start_of_current_cycle - nframes; // FIXME: maybe not..
+	const jack_nframes_t end_of_current_cycle = start_of_current_cycle + nframes;
 
 	// FIXME: ditto
 	assert(start_of_current_cycle - start_of_last_cycle == nframes);
 
 	_transport_state = jack_transport_query(_client, &_position);
 	
+	// Process events that came in during the last cycle
+	// (Aiming for jitter-free 1 block event latency, ideally)
 	if (_engine.event_source())
-		_engine.event_source()->process(*_engine.post_processor(), nframes, start_of_last_cycle, start_of_current_cycle);
+		_engine.event_source()->process(*_engine.post_processor(), nframes,
+				start_of_last_cycle, start_of_current_cycle);
 	
 	// Set buffers of patch ports to Jack port buffers (zero-copy processing)
 	for (Raul::List<JackAudioPort*>::iterator i = _ports.begin(); i != _ports.end(); ++i) {
@@ -293,14 +294,16 @@ JackAudioDriver::_process_cb(jack_nframes_t nframes)
 	}
 
 	assert(_engine.midi_driver());
-	//_engine.midi_driver()->prepare_block(start_of_last_cycle, start_of_current_cycle);
-	_engine.midi_driver()->prepare_block(start_of_current_cycle, start_of_current_cycle + nframes);
-
+	_engine.midi_driver()->pre_process(_process_context, nframes,
+			start_of_current_cycle, end_of_current_cycle);
 	
 	// Run root patch
 	if (_root_patch)
-		_root_patch->process(_process_context, nframes, start_of_current_cycle,
-				start_of_current_cycle + nframes);
+		_root_patch->process(_process_context, nframes,
+				start_of_current_cycle, end_of_current_cycle);
+	
+	_engine.midi_driver()->post_process(_process_context, nframes,
+			start_of_current_cycle, end_of_current_cycle);
 
 	return 0;
 }
diff --git a/src/libs/engine/JackMidiDriver.cpp b/src/libs/engine/JackMidiDriver.cpp
index 9abe83f6..f49794d7 100644
--- a/src/libs/engine/JackMidiDriver.cpp
+++ b/src/libs/engine/JackMidiDriver.cpp
@@ -52,7 +52,6 @@ JackMidiPort::JackMidiPort(JackMidiDriver* driver, DuplexPort* patch_port)
 		0);
 
 	patch_port->buffer(0)->clear();
-	patch_port->fixed_buffers(true);
 }
 
 
@@ -62,22 +61,25 @@ JackMidiPort::~JackMidiPort()
 }
 
 
-/** Prepare events for a block.
+/** Prepare input for a block before a cycle is run, in the audio thread.
  *
- * This is basically simple since Jack MIDI data is in-band with the audio thread.
+ * This is simple since Jack MIDI is in-band with audio.
  */
 void
-JackMidiPort::prepare_block(const SampleCount block_start, const SampleCount block_end)
+JackMidiPort::pre_process(SampleCount block_start, SampleCount block_end)
 {
-	const SampleCount    nframes     = block_end - block_start;
-	void*                jack_buffer = jack_port_get_buffer(_jack_port, nframes);
-	const jack_nframes_t event_count = jack_midi_get_event_count(jack_buffer);
+	if ( ! is_input() )
+		return;
 	
 	assert(_patch_port->poly() == 1);
 
 	MidiBuffer* patch_buf = dynamic_cast<MidiBuffer*>(_patch_port->buffer(0));
 	assert(patch_buf);
 
+	const SampleCount    nframes     = block_end - block_start;
+	void*                jack_buffer = jack_port_get_buffer(_jack_port, nframes);
+	const jack_nframes_t event_count = jack_midi_get_event_count(jack_buffer);
+
 	patch_buf->prepare_write(nframes);
 	
 	// Copy events from Jack port buffer into patch port buffer
@@ -95,6 +97,44 @@ JackMidiPort::prepare_block(const SampleCount block_start, const SampleCount blo
 }
 
 
+/** Prepare output for a block after a cycle is run, in the audio thread.
+ *
+ * This is simple since Jack MIDI is in-band with audio.
+ */
+void
+JackMidiPort::post_process(SampleCount block_start, SampleCount block_end)
+{
+	if (is_input())
+		return;
+	
+	assert(_patch_port->poly() == 1);
+
+	MidiBuffer* patch_buf = dynamic_cast<MidiBuffer*>(_patch_port->buffer(0));
+	assert(patch_buf);
+
+	const SampleCount    nframes     = block_end - block_start;
+	void*                jack_buffer = jack_port_get_buffer(_jack_port, nframes);
+	const jack_nframes_t event_count = patch_buf->event_count();
+
+	patch_buf->prepare_read(nframes);
+
+	jack_midi_clear_buffer(jack_buffer);
+	
+	double         time = 0;
+	uint32_t       size = 0;
+	unsigned char* data = NULL;
+
+	// Copy events from Jack port buffer into patch port buffer
+	for (jack_nframes_t i=0; i < event_count; ++i) {
+		patch_buf->get_event(&time, &size, &data);
+		jack_midi_event_write(jack_buffer, time, data, size);
+	}
+
+	//if (event_count)
+	//	cerr << "Jack MIDI wrote " << event_count << " events." << endl;
+}
+
+
 
 //// JackMidiDriver ////
 
@@ -137,10 +177,20 @@ JackMidiDriver::deactivate()
 /** Build flat arrays of events to be used as input for the given cycle.
  */
 void
-JackMidiDriver::prepare_block(const SampleCount block_start, const SampleCount block_end)
+JackMidiDriver::pre_process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end)
 {
 	for (Raul::List<JackMidiPort*>::iterator i = _in_ports.begin(); i != _in_ports.end(); ++i)
-		(*i)->prepare_block(block_start, block_end);
+		(*i)->pre_process(start, end);
+}
+
+
+/** Write the output from any (top-level, exported) MIDI output ports to Jack ports.
+ */
+void
+JackMidiDriver::post_process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end)
+{
+	for (Raul::List<JackMidiPort*>::iterator i = _out_ports.begin(); i != _out_ports.end(); ++i)
+		(*i)->post_process(start, end);
 }
 
 
diff --git a/src/libs/engine/JackMidiDriver.hpp b/src/libs/engine/JackMidiDriver.hpp
index c546fbec..21e1f3ec 100644
--- a/src/libs/engine/JackMidiDriver.hpp
+++ b/src/libs/engine/JackMidiDriver.hpp
@@ -42,7 +42,8 @@ public:
 	JackMidiPort(JackMidiDriver* driver, DuplexPort* port);
 	virtual ~JackMidiPort();
 
-	void prepare_block(const SampleCount block_start, const SampleCount block_end);
+	void pre_process(SampleCount block_start, SampleCount block_end);
+	void post_process(SampleCount block_start, SampleCount block_end);
 	
 	void set_name(const std::string& name) { jack_port_set_name(_jack_port, name.c_str()); };
 	
@@ -76,7 +77,8 @@ public:
 	bool is_activated() const { return _is_activated; }
 	bool is_enabled() const   { return _is_enabled; }
 	
-	void prepare_block(const SampleCount block_start, const SampleCount block_end);
+	void pre_process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
+	void post_process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 
 	JackMidiPort* create_port(DuplexPort* patch_port)
 	{ return new JackMidiPort(this, patch_port); }
diff --git a/src/libs/engine/LADSPANode.hpp b/src/libs/engine/LADSPANode.hpp
index a4ea1031..a9a67981 100644
--- a/src/libs/engine/LADSPANode.hpp
+++ b/src/libs/engine/LADSPANode.hpp
@@ -42,7 +42,7 @@ public:
 	void activate();
 	void deactivate();
 	
-	void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 	
 	void set_port_buffer(uint32_t voice, uint32_t port_num, Buffer* buf);
 
diff --git a/src/libs/engine/LV2Node.cpp b/src/libs/engine/LV2Node.cpp
index 88c002e5..5eea2f23 100644
--- a/src/libs/engine/LV2Node.cpp
+++ b/src/libs/engine/LV2Node.cpp
@@ -123,9 +123,9 @@ LV2Node::instantiate()
 	uint32_t num_ports = slv2_plugin_get_num_ports(_lv2_plugin);
 	assert(num_ports > 0);
 
-	_ports = new Raul::Array<Port*>(num_ports);
+	_ports = new Raul::Array<Port*>(num_ports, NULL);
 	
-	_instances = new Raul::Array<SLV2Instance>(_polyphony);
+	_instances = new Raul::Array<SLV2Instance>(_polyphony, NULL);
 	
 	uint32_t port_buffer_size = 0;
 	
diff --git a/src/libs/engine/LV2Node.hpp b/src/libs/engine/LV2Node.hpp
index d0941b93..a2d5bafb 100644
--- a/src/libs/engine/LV2Node.hpp
+++ b/src/libs/engine/LV2Node.hpp
@@ -51,7 +51,7 @@ public:
 	void activate();
 	void deactivate();
 	
-	void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 	
 	void set_port_buffer(uint32_t voice, uint32_t port_num, Buffer* buf);
 
diff --git a/src/libs/engine/MidiBuffer.cpp b/src/libs/engine/MidiBuffer.cpp
index 59da7646..618c7476 100644
--- a/src/libs/engine/MidiBuffer.cpp
+++ b/src/libs/engine/MidiBuffer.cpp
@@ -230,5 +230,57 @@ MidiBuffer::get_event(double*         timestamp,
 }
 
 
+/** Clear, and merge \a a and \a b into this buffer.
+ *
+ * FIXME: This is slow.
+ *
+ * \return true if complete merge was successful
+ */
+bool
+MidiBuffer::merge(const MidiBuffer& a, const MidiBuffer& b)
+{
+	// Die if a merge isn't necessary as it's expensive
+	assert(a.size() > 0 && b.size() > 0);
+
+	reset(_this_nframes);
+
+	a.rewind();
+	b.rewind();
+
+	double         a_time;
+	uint32_t       a_size;
+	unsigned char* a_data;
+	
+	double         b_time;
+	uint32_t       b_size;
+	unsigned char* b_data;
+
+	a.get_event(&a_time, &a_size, &a_data);
+	b.get_event(&b_time, &b_size, &b_data);
+
+	while (true) {
+		if (a_data && (!b_data || (a_time < b_time))) {
+			append(a_time, a_size, a_data);
+			if (a.increment())
+				a.get_event(&a_time, &a_size, &a_data);
+			else
+				a_data = NULL;
+		} else if (b_data) {
+			append(b_time, b_size, b_data);
+			if (b.increment())
+				b.get_event(&b_time, &b_size, &b_data);
+			else
+				b_data = NULL;
+		} else {
+			break;
+		}
+	}
+
+	_latest_stamp = max(a_time, b_time);
+
+	return true;
+}
+
+
 } // namespace Ingen
 
diff --git a/src/libs/engine/MidiBuffer.hpp b/src/libs/engine/MidiBuffer.hpp
index a7db7e77..f1948666 100644
--- a/src/libs/engine/MidiBuffer.hpp
+++ b/src/libs/engine/MidiBuffer.hpp
@@ -69,6 +69,7 @@ public:
 	double get_event(double* timestamp, uint32_t* size, unsigned char** data) const;
 
 	bool append(double timestamp, uint32_t size, const unsigned char* data);
+	bool merge(const MidiBuffer& a, const MidiBuffer& b);
 
 private:
 	double           _latest_stamp; ///< Highest timestamp of all events
diff --git a/src/libs/engine/MidiControlNode.hpp b/src/libs/engine/MidiControlNode.hpp
index d06e2288..3b09668f 100644
--- a/src/libs/engine/MidiControlNode.hpp
+++ b/src/libs/engine/MidiControlNode.hpp
@@ -41,7 +41,7 @@ class MidiControlNode : public NodeBase
 public:
 	MidiControlNode(const std::string& path, bool polyphonic, Patch* parent, SampleRate srate, size_t buffer_size);
 	
-	void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 	
 	void control(uchar control_num, uchar val, SampleCount offset);
 
diff --git a/src/libs/engine/MidiDriver.hpp b/src/libs/engine/MidiDriver.hpp
index acf88a3e..13b87726 100644
--- a/src/libs/engine/MidiDriver.hpp
+++ b/src/libs/engine/MidiDriver.hpp
@@ -25,6 +25,8 @@
 
 namespace Ingen {
 
+class ProcessContext;
+
 
 /** Midi driver abstract base class.
  *
@@ -35,8 +37,23 @@ class MidiDriver : public Driver
 public:
 	MidiDriver() : Driver(DataType::MIDI) {}
 
-	/** Prepare events (however neccessary) for the specified block (realtime safe) */
-	virtual void prepare_block(const SampleCount block_start, const SampleCount block_end) = 0;
+	/** Prepare input for the specified (upcoming) cycle.
+	 *
+	 * Realtime safe, run in audio thread before executing the graph for a cycle.
+	 */
+	virtual void pre_process(ProcessContext& context,
+	                         SampleCount     nframes,
+	                         FrameTime       start,
+	                         FrameTime       end) = 0;
+	
+	/** Prepare output for the specified (just completed) cycle.
+	 *
+	 * Realtime safe, run in audio thread after executing the graph for a cycle.
+	 */
+	virtual void post_process(ProcessContext& context,
+	                          SampleCount     nframes,
+	                          FrameTime       start,
+	                          FrameTime       end) = 0;
 };
 
 
@@ -73,7 +90,8 @@ public:
 	void        add_port(DriverPort* port)    {}
 	DriverPort* remove_port(const Raul::Path& path) { return NULL; }
 	
-	void prepare_block(const SampleCount block_start, const SampleCount block_end) {}
+	void pre_process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end) {}
+	void post_process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end) {}
 };
 
 
diff --git a/src/libs/engine/MidiNoteNode.hpp b/src/libs/engine/MidiNoteNode.hpp
index e86102db..a73f08f7 100644
--- a/src/libs/engine/MidiNoteNode.hpp
+++ b/src/libs/engine/MidiNoteNode.hpp
@@ -45,7 +45,7 @@ public:
 	bool prepare_poly(uint32_t poly);
 	bool apply_poly(Raul::Maid& maid, uint32_t poly);
 
-	void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 	
 	void note_on(uchar note_num, uchar velocity, FrameTime time, SampleCount nframes, FrameTime start, FrameTime end);
 	void note_off(uchar note_num, FrameTime time, SampleCount nframes, FrameTime start, FrameTime end);
diff --git a/src/libs/engine/MidiTriggerNode.hpp b/src/libs/engine/MidiTriggerNode.hpp
index 389768f8..2e1959b9 100644
--- a/src/libs/engine/MidiTriggerNode.hpp
+++ b/src/libs/engine/MidiTriggerNode.hpp
@@ -43,7 +43,7 @@ class MidiTriggerNode : public NodeBase
 public:
 	MidiTriggerNode(const std::string& path, bool polyphonic, Patch* parent, SampleRate srate, size_t buffer_size);
 
-	void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 	
 	void note_on(uchar note_num, uchar velocity, FrameTime time, SampleCount nframes, FrameTime start, FrameTime end);
 	void note_off(uchar note_num, FrameTime time, SampleCount nframes, FrameTime start, FrameTime end);
diff --git a/src/libs/engine/Node.hpp b/src/libs/engine/Node.hpp
index 8db11ad8..b305bc45 100644
--- a/src/libs/engine/Node.hpp
+++ b/src/libs/engine/Node.hpp
@@ -117,7 +117,7 @@ public:
 	 * @a start and @a end are transport times: end is not redundant in the case
 	 * of varispeed, where end-start != nframes.
 	 */
-	virtual void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end) = 0;
+	virtual void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end) = 0;
 
 	virtual void set_port_buffer(uint32_t voice, uint32_t port_num, Buffer* buf) = 0;
 
diff --git a/src/libs/engine/NodeBase.cpp b/src/libs/engine/NodeBase.cpp
index 5e6176f0..54caf8f8 100644
--- a/src/libs/engine/NodeBase.cpp
+++ b/src/libs/engine/NodeBase.cpp
@@ -61,8 +61,9 @@ NodeBase::~NodeBase()
 	delete _providers;
 	delete _dependants;
 	
-	for (uint32_t i=0; i < num_ports(); ++i)
-		delete _ports->at(i);
+	if (_ports)
+		for (uint32_t i=0; i < num_ports(); ++i)
+			delete _ports->at(i);
 }
 
 
diff --git a/src/libs/engine/NodeBase.hpp b/src/libs/engine/NodeBase.hpp
index d43a84a6..b5dee178 100644
--- a/src/libs/engine/NodeBase.hpp
+++ b/src/libs/engine/NodeBase.hpp
@@ -70,7 +70,7 @@ public:
 	virtual unsigned n_inputs_ready() const { return _n_inputs_ready.get(); }
 
 	virtual void pre_process(SampleCount nframes, FrameTime start, FrameTime end);
-	virtual void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end) = 0;
+	virtual void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end) = 0;
 	virtual void post_process(SampleCount nframes, FrameTime start, FrameTime end);
 		
 	virtual void set_port_buffer(uint32_t voice, uint32_t port_num, Buffer* buf) {}
diff --git a/src/libs/engine/OutputPort.hpp b/src/libs/engine/OutputPort.hpp
index 8f12d252..07daf6b6 100644
--- a/src/libs/engine/OutputPort.hpp
+++ b/src/libs/engine/OutputPort.hpp
@@ -50,7 +50,7 @@ public:
 	{}
 
 	void pre_process(SampleCount nframes, FrameTime start, FrameTime end);
-	void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 	void post_process(SampleCount nframes, FrameTime start, FrameTime end);
 	
 	virtual ~OutputPort() {}
diff --git a/src/libs/engine/Patch.hpp b/src/libs/engine/Patch.hpp
index 75de93cb..fd95e5bb 100644
--- a/src/libs/engine/Patch.hpp
+++ b/src/libs/engine/Patch.hpp
@@ -54,7 +54,7 @@ public:
 	void activate();
 	void deactivate();
 
-	void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 	
 	void set_buffer_size(size_t size);
 	
diff --git a/src/libs/engine/TransportNode.hpp b/src/libs/engine/TransportNode.hpp
index a12a8cfe..bf11f309 100644
--- a/src/libs/engine/TransportNode.hpp
+++ b/src/libs/engine/TransportNode.hpp
@@ -36,7 +36,7 @@ class TransportNode : public NodeBase
 public:
 	TransportNode(const std::string& path, bool polyphonic, Patch* parent, SampleRate srate, size_t buffer_size);
 
-	virtual void process(ProcessContext& events, SampleCount nframes, FrameTime start, FrameTime end);
+	virtual void process(ProcessContext& context, SampleCount nframes, FrameTime start, FrameTime end);
 };
 
 
diff --git a/src/libs/engine/events/AddPortEvent.cpp b/src/libs/engine/events/AddPortEvent.cpp
index 28273815..d31c2169 100644
--- a/src/libs/engine/events/AddPortEvent.cpp
+++ b/src/libs/engine/events/AddPortEvent.cpp
@@ -115,15 +115,13 @@ AddPortEvent::pre_process()
 			if (!_patch->parent()) {
 				if (_type == "ingen:audio")
 					_driver_port = _engine.audio_driver()->create_port(
-						dynamic_cast<DuplexPort*>(_patch_port));
+							dynamic_cast<DuplexPort*>(_patch_port));
 				else if (_type == "ingen:midi")
 					_driver_port = _engine.midi_driver()->create_port(
-						dynamic_cast<DuplexPort*>(_patch_port));
-			}
-
-			if (_type == "ingen:osc" && _engine.osc_driver()) {
-				_driver_port = _engine.osc_driver()->create_port(
-					dynamic_cast<DuplexPort*>(_patch_port));
+							dynamic_cast<DuplexPort*>(_patch_port));
+				else if (_type == "ingen:osc" && _engine.osc_driver())
+					_driver_port = _engine.osc_driver()->create_port(
+							dynamic_cast<DuplexPort*>(_patch_port));
 			}
 
 			assert(_ports_array->size() == _patch->num_ports());