Enable Lv2 Atom ports

All Atom ports are now being created and connected. Currently only MIDI
input ports are supplied with data.

Major contribution to #562 ("lv2 support").

include/Lv2ControlBase.h

@@ -100,8 +100,12 @@ protected:
 	/*
 		utils for the run thread
 	*/
-	//! Copy values from all connected models into the respective ports
+	//! Copy values from the LMMS core (connected models, MIDI events, ...) into
+	//! the respective ports
 	void copyModelsFromLmms();
+	//! Bring values from all ports to the LMMS core
+	void copyModelsToLmms() const;
+
 	//! Copy buffer passed by LMMS into our ports
 	void copyBuffersFromLmms(const sampleFrame *buf, fpp_t frames);
 	//! Copy our ports into buffers passed by LMMS
@@ -123,6 +127,9 @@ protected:
 	*/
 	std::size_t controlCount() const;
 	QString nodeName() const { return "lv2controls"; }
+	bool hasNoteInput() const;
+	void handleMidiInputEvent(const class MidiEvent &event,
+		const class MidiTime &time, f_cnt_t offset);
 
 private:
 	//! Return the DataFile settings type

include/Lv2Evbuf.h

@@ -0,0 +1,149 @@
+/*
+ * lv2_evbuf.h - Lv2 event buffer definitions
+ *
+ * Copyright (c) 2019-2020 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+/*
+ * The original code was written by David Robillard <http://drobilla.net>
+ * Original version: 6f22ee0 from https://github.com/drobilla/jalv.git
+ * Minor changes have been done, but no functional changes.
+ * Considering this as an "external library", the identifiers do not need to
+ * match the LMMS coding conventions.
+ */
+
+#ifndef LV2_EVBUF_H
+#define LV2_EVBUF_H
+
+#include "lmmsconfig.h"
+
+#ifdef LMMS_HAVE_LV2
+
+#include <cstdint>
+
+/**
+   An abstract/opaque LV2 event buffer.
+*/
+typedef struct LV2_Evbuf_Impl LV2_Evbuf;
+
+/**
+   An iterator over an LV2_Evbuf.
+*/
+typedef struct {
+	LV2_Evbuf* evbuf;
+	uint32_t offset;
+} LV2_Evbuf_Iterator;
+
+/**
+   Allocate a new, empty event buffer.
+   URIDs for atom:Chunk and atom:Sequence must be passed for LV2_EVBUF_ATOM.
+*/
+LV2_Evbuf*
+lv2_evbuf_new(uint32_t capacity, uint32_t atom_Chunk, uint32_t atom_Sequence);
+
+/**
+   Free an event buffer allocated with lv2_evbuf_new.
+*/
+void
+lv2_evbuf_free(LV2_Evbuf* evbuf);
+
+/**
+   Clear and initialize an existing event buffer.
+   The contents of buf are ignored entirely and overwritten, except capacity
+   which is unmodified.
+   If input is false and this is an atom buffer, the buffer will be prepared
+   for writing by the plugin.  This MUST be called before every run cycle.
+*/
+void
+lv2_evbuf_reset(LV2_Evbuf* evbuf, bool input);
+
+/**
+   Return the total padded size of the events stored in the buffer.
+*/
+uint32_t
+lv2_evbuf_get_size(LV2_Evbuf* evbuf);
+
+/**
+   Return the actual buffer implementation.
+   The format of the buffer returned depends on the buffer type.
+*/
+void*
+lv2_evbuf_get_buffer(LV2_Evbuf* evbuf);
+
+/**
+   Return an iterator to the start of `evbuf`.
+*/
+LV2_Evbuf_Iterator
+lv2_evbuf_begin(LV2_Evbuf* evbuf);
+
+/**
+   Return an iterator to the end of `evbuf`.
+*/
+LV2_Evbuf_Iterator
+lv2_evbuf_end(LV2_Evbuf* evbuf);
+
+/**
+   Check if `iter` is valid.
+   @return True if `iter` is valid, otherwise false (past end of buffer)
+*/
+bool
+lv2_evbuf_is_valid(LV2_Evbuf_Iterator iter);
+
+/**
+   Advance `iter` forward one event.
+   `iter` must be valid.
+   @return True if `iter` is valid, otherwise false (reached end of buffer)
+*/
+LV2_Evbuf_Iterator
+lv2_evbuf_next(LV2_Evbuf_Iterator iter);
+
+/**
+   Dereference an event iterator (i.e. get the event currently pointed to).
+   `iter` must be valid.
+   `type` Set to the type of the event.
+   `size` Set to the size of the event.
+   `data` Set to the contents of the event.
+   @return True on success.
+*/
+bool
+lv2_evbuf_get(	LV2_Evbuf_Iterator iter,
+				uint32_t* frames,
+				uint32_t* type,
+				uint32_t* size,
+				uint8_t** data);
+
+/**
+   Write an event at `iter`.
+   The event (if any) pointed to by `iter` will be overwritten, and `iter`
+   incremented to point to the following event (i.e. several calls to this
+   function can be done in sequence without twiddling iter in-between).
+   @return True if event was written, otherwise false (buffer is full).
+*/
+bool
+lv2_evbuf_write(	LV2_Evbuf_Iterator* iter,
+					uint32_t frames,
+					uint32_t type,
+					uint32_t size,
+					const uint8_t* data);
+
+#endif // LMMS_HAVE_LV2
+
+#endif // LV2_EVBUF_H

include/Lv2Ports.h

@@ -37,6 +37,7 @@
 #include "PluginIssue.h"
 
 struct ConnectPortVisitor;
+typedef struct LV2_Evbuf_Impl LV2_Evbuf;
 
 namespace Lv2Ports {
 
@@ -53,7 +54,7 @@ enum class Type {
 	Unknown,
 	Control,
 	Audio,
-	Event, //!< TODO: unused, describe
+	AtomSeq,
 	Cv //!< TODO: unused, describe
 };
 
@@ -74,6 +75,7 @@ struct ControlPortBase;
 struct Control;
 struct Audio;
 struct Cv;
+struct AtomSeq;
 struct Unknown;
 
 struct ConstVisitor
@@ -82,6 +84,7 @@ struct ConstVisitor
 	virtual void visit(const Lv2Ports::Control& ) {}
 	virtual void visit(const Lv2Ports::Audio& ) {}
 	virtual void visit(const Lv2Ports::Cv& ) {}
+	virtual void visit(const Lv2Ports::AtomSeq& ) {}
 	virtual void visit(const Lv2Ports::Unknown& ) {}
 
 	virtual ~ConstVisitor();
@@ -93,6 +96,7 @@ struct Visitor
 	virtual void visit(Lv2Ports::Control& ) {}
 	virtual void visit(Lv2Ports::Audio& ) {}
 	virtual void visit(Lv2Ports::Cv& ) {}
+	virtual void visit(Lv2Ports::AtomSeq& ) {}
 	virtual void visit(Lv2Ports::Unknown& ) {}
 
 	virtual ~Visitor();
@@ -192,6 +196,23 @@ private:
 	friend struct ::ConnectPortVisitor;
 };
 
+struct AtomSeq : public VisitablePort<AtomSeq, PortBase>
+{
+	enum FlagType
+	{
+		None = 0,
+		Midi = 1
+	};
+	unsigned flags = FlagType::None;
+
+	struct Lv2EvbufDeleter
+	{
+		void operator()(LV2_Evbuf* n);
+	};
+	using AutoLv2Evbuf = std::unique_ptr<LV2_Evbuf, Lv2EvbufDeleter>;
+	AutoLv2Evbuf m_buf;
+};
+
 struct Unknown : public VisitablePort<Unknown, PortBase>
 {
 };

include/Lv2Proc.h

@@ -36,15 +36,18 @@
 #include "Lv2Basics.h"
 #include "Lv2Features.h"
 #include "LinkedModelGroups.h"
+#include "MidiEvent.h"
+#include "MidiTime.h"
 #include "Plugin.h"
 #include "PluginIssue.h"
-
+#include "../src/3rdparty/ringbuffer/include/ringbuffer/ringbuffer.h"
 
 // forward declare port structs/enums
 namespace Lv2Ports
 {
 	struct Audio;
 	struct PortBase;
+	struct AtomSeq;
 
 	enum class Type;
 	enum class Flow;
@@ -106,8 +109,11 @@ public:
 	/*
 		utils for the run thread
 	*/
-	//! Copy values from all connected models into the respective ports
+	//! Copy values from the LMMS core (connected models, MIDI events, ...) into
+	//! the respective ports
 	void copyModelsFromCore();
+	//! Bring values from all ports to the LMMS core
+	void copyModelsToCore();
 	/**
 	 * Copy buffer passed by the core into our ports
 	 * @param buf buffer of sample frames, each sample frame is something like
@@ -137,11 +143,15 @@ public:
 	//! Run the Lv2 plugin instance for @param frames frames
 	void run(fpp_t frames);
 
+	void handleMidiInputEvent(const class MidiEvent &event,
+		const MidiTime &time, f_cnt_t offset);
+
 	/*
 		misc
 	 */
 	class AutomatableModel *modelAtPort(const QString &uri); // unused currently
 	std::size_t controlCount() const { return LinkedModelGroup::modelNum(); }
+	bool hasNoteInput() const;
 
 protected:
 	/*
@@ -159,8 +169,25 @@ private:
 	LilvInstance* m_instance;
 	Lv2Features m_features;
 
+	// full list of ports
 	std::vector<std::unique_ptr<Lv2Ports::PortBase>> m_ports;
+	// quick reference to specific, unique ports
 	StereoPortRef m_inPorts, m_outPorts;
+	Lv2Ports::AtomSeq *m_midiIn = nullptr, *m_midiOut = nullptr;
+
+	// MIDI
+	// many things here may be moved into the `Instrument` class
+	constexpr const static std::size_t m_maxMidiInputEvents = 1024;
+	//! spinlock for the MIDI ringbuffer (for MIDI events going to the plugin)
+	std::atomic_flag m_ringLock = ATOMIC_FLAG_INIT;
+
+	//! MIDI ringbuffer (for MIDI events going to the plugin)
+	ringbuffer_t<struct MidiInputEvent> m_midiInputBuf;
+	//! MIDI ringbuffer reader
+	ringbuffer_reader_t<struct MidiInputEvent> m_midiInputReader;
+
+	// other
+	static std::size_t minimumEvbufSize() { return 1 << 15; /* ardour uses this*/ }
 
 	//! models for the controls, sorted by port symbols
 	std::map<std::string, AutomatableModel *> m_connectedModels;

include/Lv2UridCache.h

@@ -37,7 +37,7 @@ class Lv2UridCache
 public:
 	enum class Id //!< ID for m_uridCache array
 	{
-		midi_MidiEvent, //!< just an example, unused yet
+		midi_MidiEvent,
 		size
 	};
 	//! Return URID for a cache ID