ardour/libs/ardour/lv2_plugin.cc

/*
    Copyright (C) 2008-2011 Paul Davis
    Author: David Robillard

    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; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <string>
#include <vector>

#include <cmath>
#include <cstdlib>
#include <cstring>

#include <glibmm.h>

#include "pbd/compose.h"
#include "pbd/error.h"
#include "pbd/pathscanner.h"
#include "pbd/xml++.h"

#include "ardour/ardour.h"
#include "ardour/audio_buffer.h"
#include "ardour/audioengine.h"
#include "ardour/debug.h"
#include "ardour/lv2_event_buffer.h"
#include "ardour/lv2_plugin.h"
#include "ardour/session.h"

#include "pbd/stl_delete.h"

#include "i18n.h"
#include <locale.h>

#include "lv2ext/lv2_persist.h"
#include "lv2_pfile.h"

#define NS_DC   "http://dublincore.org/documents/dcmi-namespace/"
#define NS_LV2  "http://lv2plug.in/ns/lv2core#"
#define NS_PSET "http://lv2plug.in/ns/dev/presets#"
#define NS_UI   "http://lv2plug.in/ns/extensions/ui#"

using namespace std;
using namespace ARDOUR;
using namespace PBD;

URIMap LV2Plugin::  _uri_map;
uint32_t LV2Plugin::_midi_event_type = _uri_map.uri_to_id(
        "http://lv2plug.in/ns/ext/event",
        "http://lv2plug.in/ns/ext/midi#MidiEvent");

LV2Plugin::LV2Plugin (AudioEngine& engine,
                      Session&     session,
                      LV2World&    world,
                      SLV2Plugin   plugin,
                      framecnt_t   rate)
	: Plugin(engine, session)
	, _world(world)
	, _features(NULL)
{
	init(world, plugin, rate);
}

LV2Plugin::LV2Plugin (const LV2Plugin& other)
	: Plugin(other)
	, _world(other._world)
	, _features(NULL)
{
	init(other._world, other._plugin, other._sample_rate);

	for (uint32_t i = 0; i < parameter_count(); ++i) {
		_control_data[i] = other._shadow_data[i];
		_shadow_data[i]  = other._shadow_data[i];
	}
}

void
LV2Plugin::init(LV2World& world, SLV2Plugin plugin, framecnt_t rate)
{
	DEBUG_TRACE(DEBUG::LV2, "LV2 plugin init\n");

	_world                = world;
	_plugin               = plugin;
	_ui                   = NULL;
	_control_data         = 0;
	_shadow_data          = 0;
	_latency_control_port = 0;
	_was_activated        = false;

	_instance_access_feature.URI = "http://lv2plug.in/ns/ext/instance-access";
	_data_access_feature.URI     = "http://lv2plug.in/ns/ext/data-access";
	_persist_feature.URI         = "http://lv2plug.in/ns/ext/persist";
	_persist_feature.data        = NULL;

	SLV2Value persist_uri = slv2_value_new_uri(_world.world, _persist_feature.URI);
	_supports_persist = slv2_plugin_has_feature(plugin, persist_uri);
	slv2_value_free(persist_uri);

	_features    = (LV2_Feature**)malloc(sizeof(LV2_Feature*) * 5);
	_features[0] = &_instance_access_feature;
	_features[1] = &_data_access_feature;
	_features[2] = &_persist_feature;
	_features[3] = _uri_map.feature();
	_features[4] = NULL;

	_instance = slv2_plugin_instantiate(plugin, rate, _features);
	_name     = slv2_plugin_get_name(plugin);
	_author   = slv2_plugin_get_author_name(plugin);

	if (_instance == 0) {
		error << _("LV2: Failed to instantiate plugin ")
		      << slv2_value_as_string(slv2_plugin_get_uri(plugin)) << endmsg;
		throw failed_constructor();
	}

	_instance_access_feature.data              = (void*)_instance->lv2_handle;
	_data_access_extension_data.extension_data = _instance->lv2_descriptor->extension_data;
	_data_access_feature.data                  = &_data_access_extension_data;

	if (slv2_plugin_has_feature(plugin, world.in_place_broken)) {
		error << string_compose(
		    _("LV2: \"%1\" cannot be used, since it cannot do inplace processing"),
		    slv2_value_as_string(_name)) << endmsg;
		slv2_value_free(_name);
		slv2_value_free(_author);
		throw failed_constructor();
	}

	_sample_rate = rate;

	const uint32_t num_ports    = slv2_plugin_get_num_ports(plugin);
	const bool     latent       = slv2_plugin_has_latency(plugin);
	const uint32_t latency_port = (latent)
	    ? slv2_plugin_get_latency_port_index(plugin)
		: 0;

	_control_data = new float[num_ports];
	_shadow_data  = new float[num_ports];
	_defaults     = new float[num_ports];

	for (uint32_t i = 0; i < num_ports; ++i) {
		SLV2Port  port = slv2_plugin_get_port_by_index(plugin, i);
		SLV2Value sym  = slv2_port_get_symbol(_plugin, port);

		// Store index in map so we can look up index by symbol
		_port_indices.insert(std::make_pair(slv2_value_as_string(sym), i));

		// Get range and default value if applicable
		if (parameter_is_control(i)) {
			SLV2Value def;
			slv2_port_get_range(plugin, port, &def, NULL, NULL);
			_defaults[i] = def ? slv2_value_as_float(def) : 0.0f;
			slv2_value_free(def);

			slv2_instance_connect_port(_instance, i, &_control_data[i]);

			if (latent && ( i == latency_port) ) {
				_latency_control_port  = &_control_data[i];
				*_latency_control_port = 0;
			}

			if (parameter_is_input(i)) {
				_shadow_data[i] = default_value(i);
			}
		} else {
			_defaults[i] = 0.0f;
		}
	}

	SLV2UIs uis = slv2_plugin_get_uis(_plugin);
	if (slv2_uis_size(uis) > 0) {
		// Look for Gtk native UI
		for (unsigned i = 0; i < slv2_uis_size(uis); ++i) {
			SLV2UI ui = slv2_uis_get_at(uis, i);
			if (slv2_ui_is_a(ui, _world.gtk_gui)) {
				_ui = ui;
				break;
			}
		}

		// If Gtk UI is not available, try to find external UI
		if (!_ui) {
			for (unsigned i = 0; i < slv2_uis_size(uis); ++i) {
				SLV2UI ui = slv2_uis_get_at(uis, i);
				if (slv2_ui_is_a(ui, _world.external_gui)) {
					_ui = ui;
					break;
				}
			}
		}
	}

	latency_compute_run();
}

LV2Plugin::~LV2Plugin ()
{
	DEBUG_TRACE(DEBUG::LV2, string_compose("%1 destroy\n", name()));

	deactivate();
	cleanup();

	slv2_instance_free(_instance);
	slv2_value_free(_name);
	slv2_value_free(_author);

	delete [] _control_data;
	delete [] _shadow_data;
}

bool
LV2Plugin::is_external_ui() const
{
	return slv2_ui_is_a(_ui, _world.external_gui);
}

string
LV2Plugin::unique_id() const
{
	return slv2_value_as_uri(slv2_plugin_get_uri(_plugin));
}

float
LV2Plugin::default_value(uint32_t port)
{
	return _defaults[port];
}

const char*
LV2Plugin::port_symbol(uint32_t index) const
{
	SLV2Port port = slv2_plugin_get_port_by_index(_plugin, index);
	if (!port) {
		error << name() << ": Invalid port index " << index << endmsg;
	}

	SLV2Value sym = slv2_port_get_symbol(_plugin, port);
	return slv2_value_as_string(sym);
}

void
LV2Plugin::set_parameter(uint32_t which, float val)
{
	DEBUG_TRACE(DEBUG::LV2, string_compose(
	                "%1 set parameter %2 to %3\n", name(), which, val));

	if (which < slv2_plugin_get_num_ports(_plugin)) {
		_shadow_data[which] = val;
	} else {
		warning << string_compose(
		    _("Illegal parameter number used with plugin \"%1\". "
		      "This is a bug in either %2 or the LV2 plugin <%3>"),
		    name(), PROGRAM_NAME, unique_id()) << endmsg;
	}

	Plugin::set_parameter(which, val);
}

float
LV2Plugin::get_parameter(uint32_t which) const
{
	if (parameter_is_input(which)) {
		return (float)_shadow_data[which];
	} else {
		return (float)_control_data[which];
	}
	return 0.0f;
}

uint32_t
LV2Plugin::nth_parameter(uint32_t n, bool& ok) const
{
	ok = false;
	for (uint32_t c = 0, x = 0; x < slv2_plugin_get_num_ports(_plugin); ++x) {
		if (parameter_is_control(x)) {
			if (c++ == n) {
				ok = true;
				return x;
			}
		}
	}

	return 0;
}

void
LV2Plugin::lv2_persist_store_callback(void*       callback_data,
                                      const char* key,
                                      const void* value,
                                      size_t      size,
                                      uint32_t    type)
{
	LV2PFile file = (LV2PFile)callback_data;

	// FIXME: assumes URIs are mapped in the default context (or not event, at least)
	const char* type_uri = LV2Plugin::_uri_map.id_to_uri(NULL, type);
	cout << "LV2 PERSIST STORE " << key << " = " << value << " :: " << type_uri << endl;
	lv2_pfile_write(file, key, value, size, type_uri);
}

const void*
LV2Plugin::lv2_persist_retrieve_callback(void*       callback_data,
                                         const char* key,
                                         size_t*     size,
                                         uint32_t*   type)
{
	//LV2PFile file = (LV2PFile)callback_data;
	cout << "LV2 PERSIST RETRIEVE " << key << endl;
	return NULL;
}

void
LV2Plugin::add_state(XMLNode* root) const
{
	XMLNode*    child;
	char        buf[16];
	LocaleGuard lg(X_("POSIX"));

	for (uint32_t i = 0; i < parameter_count(); ++i) {
		if (parameter_is_input(i) && parameter_is_control(i)) {
			child = new XMLNode("Port");
			child->add_property("symbol", port_symbol(i));
			snprintf(buf, sizeof(buf), "%+f", _shadow_data[i]);
			child->add_property("value", string(buf));
			root->add_child_nocopy(*child);
		}
	}

	if (_supports_persist) {
		// Create state directory for this plugin instance
		const std::string state_filename = _id.to_s() + ".lv2pfile";
		const std::string state_path     = Glib::build_filename(
		        _session.plugins_dir(), state_filename);

		cout << "Saving LV2 plugin state to " << state_path << endl;

		// Get LV2 Persist extension data from plugin instance
		LV2_Persist* persist = (LV2_Persist*)slv2_instance_get_extension_data(
		        _instance, "http://lv2plug.in/ns/ext/persist");
		if (!persist) {
			warning << string_compose(
			    _("Plugin \"%1\% failed to return LV2 persist data"),
			    unique_id());
			return;
		}

		LV2PFile file = lv2_pfile_open(state_path.c_str(), true);
		persist->save(_instance->lv2_handle, &LV2Plugin::lv2_persist_store_callback, file);
		lv2_pfile_close(file);

		root->add_property("state-file", state_filename);
	}
}

static inline SLV2Value
get_value(SLV2Plugin p, SLV2Value subject, SLV2Value predicate)
{
	SLV2Values vs = slv2_plugin_get_value_for_subject(p, subject, predicate);
	return vs ? slv2_values_get_at(vs, 0) : NULL;
}

void
LV2Plugin::find_presets()
{
	SLV2Value dc_title       = slv2_value_new_uri(_world.world, NS_DC   "title");
	SLV2Value pset_hasPreset = slv2_value_new_uri(_world.world, NS_PSET "hasPreset");

	SLV2Values presets = slv2_plugin_get_value(_plugin, pset_hasPreset);
	for (unsigned i = 0; i < slv2_values_size(presets); ++i) {
		SLV2Value preset = slv2_values_get_at(presets, i);
		SLV2Value name   = get_value(_plugin, preset, dc_title);
		if (name) {
			_presets.insert(std::make_pair(slv2_value_as_string(preset),
			                               PresetRecord(
			                                   slv2_value_as_string(preset),
			                                   slv2_value_as_string(name))));
		} else {
			warning << string_compose(
			    _("Plugin \"%1\% preset \"%2%\" is missing a dc:title\n"),
			    unique_id(), slv2_value_as_string(preset));
		}
	}
	slv2_values_free(presets);

	slv2_value_free(pset_hasPreset);
	slv2_value_free(dc_title);
}

bool
LV2Plugin::load_preset(PresetRecord r)
{
	Plugin::load_preset(r);

#ifdef HAVE_NEW_SLV2
	// New (>= 0.7.0) slv2 no longer supports SPARQL, but exposes blank nodes
	// so querying ports is possible with the simple/fast API
	SLV2Value lv2_port   = slv2_value_new_uri(_world.world, NS_LV2 "port");
	SLV2Value lv2_symbol = slv2_value_new_uri(_world.world, NS_LV2 "symbol");
	SLV2Value pset_value = slv2_value_new_uri(_world.world, NS_PSET "value");
	SLV2Value preset     = slv2_value_new_uri(_world.world, r.uri.c_str());

	SLV2Values ports = slv2_plugin_get_value_for_subject(_plugin, preset, lv2_port);
	for (unsigned i = 0; i < slv2_values_size(ports); ++i) {
		SLV2Value port   = slv2_values_get_at(ports, i);
		SLV2Value symbol = get_value(_plugin, port, lv2_symbol);
		SLV2Value value  = get_value(_plugin, port, pset_value);
		if (value && slv2_value_is_float(value)) {
			set_parameter(_port_indices[slv2_value_as_string(symbol)],
			              slv2_value_as_float(value));
		}
	}
	slv2_values_free(ports);

	slv2_value_free(preset);
	slv2_value_free(pset_value);
	slv2_value_free(lv2_symbol);
	slv2_value_free(lv2_port);
#else
	const string query = string(
	        "PREFIX lv2p: <http://lv2plug.in/ns/dev/presets#>\n"
	        "PREFIX dc:  <http://dublincore.org/documents/dcmi-namespace/>\n"
	        "SELECT ?sym ?val WHERE { <") + r.uri + "> lv2:port ?port . "
	    " ?port lv2:symbol ?sym ; lv2p:value ?val . }";
	SLV2Results values = slv2_plugin_query_sparql(_plugin, query.c_str());
	for (; !slv2_results_finished(values); slv2_results_next(values)) {
		SLV2Value sym = slv2_results_get_binding_value(values, 0);
		SLV2Value val = slv2_results_get_binding_value(values, 1);
		if (slv2_value_is_float(val)) {
			uint32_t index = _port_indices[slv2_value_as_string(sym)];
			set_parameter(index, slv2_value_as_float(val));
		}
	}
	slv2_results_free(values);
#endif
	return true;
}

std::string
LV2Plugin::do_save_preset(string /*name*/)
{
	return "";
}

void
LV2Plugin::do_remove_preset(string /*name*/)
{}

bool
LV2Plugin::has_editor() const
{
	return _ui != NULL;
}

int
LV2Plugin::set_state(const XMLNode& node, int version)
{
	XMLNodeList          nodes;
	const XMLProperty*   prop;
	XMLNodeConstIterator iter;
	XMLNode*             child;
	const char*          sym;
	const char*          value;
	uint32_t             port_id;
	LocaleGuard          lg(X_("POSIX"));

	if (node.name() != state_node_name()) {
		error << _("Bad node sent to LV2Plugin::set_state") << endmsg;
		return -1;
	}

	if (version < 3000) {
		nodes = node.children("port");
	} else {
		nodes = node.children("Port");
	}

	for (iter = nodes.begin(); iter != nodes.end(); ++iter) {

		child = *iter;

		if ((prop = child->property("symbol")) != 0) {
			sym = prop->value().c_str();
		} else {
			warning << _("LV2: port has no symbol, ignored") << endmsg;
			continue;
		}

		map<string, uint32_t>::iterator i = _port_indices.find(sym);

		if (i != _port_indices.end()) {
			port_id = i->second;
		} else {
			warning << _("LV2: port has unknown index, ignored") << endmsg;
			continue;
		}

		if ((prop = child->property("value")) != 0) {
			value = prop->value().c_str();
		} else {
			warning << _("LV2: port has no value, ignored") << endmsg;
			continue;
		}

		set_parameter(port_id, atof(value));
	}

	if ((prop = node.property("state-file")) != 0) {
		std::string state_path = Glib::build_filename(_session.plugins_dir(),
		                                              prop->value());

		// Get LV2 Persist extension data from plugin instance
		LV2_Persist* persist = (LV2_Persist*)slv2_instance_get_extension_data(
		        _instance, "http://lv2plug.in/ns/ext/persist");
		if (persist) {
			cout << "Loading LV2 state from " << state_path << endl;
			LV2PFile file = lv2_pfile_open(state_path.c_str(), false);
			persist->restore(_instance->lv2_handle,
			                 &LV2Plugin::lv2_persist_retrieve_callback,
			                 file);
			lv2_pfile_close(file);
		} else {
			warning << string_compose(
			    _("Plugin \"%1\% failed to return LV2 persist data"),
			    unique_id());
		}
	}

	latency_compute_run();

	return Plugin::set_state(node, version);
}

int
LV2Plugin::get_parameter_descriptor(uint32_t which, ParameterDescriptor& desc) const
{
	SLV2Port port = slv2_plugin_get_port_by_index(_plugin, which);

	SLV2Value def, min, max;
	slv2_port_get_range(_plugin, port, &def, &min, &max);

	desc.integer_step = slv2_port_has_property(_plugin, port, _world.integer);
	desc.toggled      = slv2_port_has_property(_plugin, port, _world.toggled);
	desc.logarithmic  = slv2_port_has_property(_plugin, port, _world.logarithmic);
	desc.sr_dependent = slv2_port_has_property(_plugin, port, _world.srate);
	desc.label        = slv2_value_as_string(slv2_port_get_name(_plugin, port));
	desc.lower        = min ? slv2_value_as_float(min) : 0.0f;
	desc.upper        = max ? slv2_value_as_float(max) : 1.0f;
	desc.min_unbound  = false; // TODO: LV2 extension required
	desc.max_unbound  = false; // TODO: LV2 extension required

	if (desc.integer_step) {
		desc.step      = 1.0;
		desc.smallstep = 0.1;
		desc.largestep = 10.0;
	} else {
		const float delta = desc.upper - desc.lower;
		desc.step      = delta / 1000.0f;
		desc.smallstep = delta / 10000.0f;
		desc.largestep = delta / 10.0f;
	}

	slv2_value_free(def);
	slv2_value_free(min);
	slv2_value_free(max);

	return 0;
}

string
LV2Plugin::describe_parameter(Evoral::Parameter which)
{
	if (( which.type() == PluginAutomation) && ( which.id() < parameter_count()) ) {
		SLV2Value name = slv2_port_get_name(_plugin,
		                                    slv2_plugin_get_port_by_index(_plugin, which.id()));
		string ret(slv2_value_as_string(name));
		slv2_value_free(name);
		return ret;
	} else {
		return "??";
	}
}

framecnt_t
LV2Plugin::signal_latency() const
{
	if (_latency_control_port) {
		return (framecnt_t)floor(*_latency_control_port);
	} else {
		return 0;
	}
}

set<Evoral::Parameter>
LV2Plugin::automatable() const
{
	set<Evoral::Parameter> ret;

	for (uint32_t i = 0; i < parameter_count(); ++i) {
		if (parameter_is_input(i) && parameter_is_control(i)) {
			ret.insert(ret.end(), Evoral::Parameter(PluginAutomation, 0, i));
		}
	}

	return ret;
}

void
LV2Plugin::activate()
{
	DEBUG_TRACE(DEBUG::LV2, string_compose("%1 activate\n", name()));

	if (!_was_activated) {
		slv2_instance_activate(_instance);
		_was_activated = true;
	}
}

void
LV2Plugin::deactivate()
{
	DEBUG_TRACE(DEBUG::LV2, string_compose("%1 deactivate\n", name()));

	if (_was_activated) {
		slv2_instance_deactivate(_instance);
		_was_activated = false;
	}
}

void
LV2Plugin::cleanup()
{
	DEBUG_TRACE(DEBUG::LV2, string_compose("%1 cleanup\n", name()));

	activate();
	deactivate();
	slv2_instance_free(_instance);
	_instance = NULL;
}

int
LV2Plugin::connect_and_run(BufferSet& bufs,
	ChanMapping in_map, ChanMapping out_map,
	pframes_t nframes, framecnt_t offset)
{
	DEBUG_TRACE(DEBUG::LV2, string_compose("%1 run %2 offset %3\n", name(), nframes, offset));
	Plugin::connect_and_run(bufs, in_map, out_map, nframes, offset);

	cycles_t then = get_cycles();

	uint32_t audio_in_index  = 0;
	uint32_t audio_out_index = 0;
	uint32_t midi_in_index   = 0;
	uint32_t midi_out_index  = 0;
	for (uint32_t port_index = 0; port_index < parameter_count(); ++port_index) {
		if (parameter_is_audio(port_index)) {
			if (parameter_is_input(port_index)) {
				const uint32_t buf_index = in_map.get(DataType::AUDIO, audio_in_index++);
				slv2_instance_connect_port(_instance, port_index,
				                           bufs.get_audio(buf_index).data(offset));
			} else if (parameter_is_output(port_index)) {
				const uint32_t buf_index = out_map.get(DataType::AUDIO, audio_out_index++);
				//cerr << port_index << " : " << " AUDIO OUT " << buf_index << endl;
				slv2_instance_connect_port(_instance, port_index,
				                           bufs.get_audio(buf_index).data(offset));
			}
		} else if (parameter_is_midi(port_index)) {
			if (parameter_is_input(port_index)) {
				const uint32_t buf_index = in_map.get(DataType::MIDI, midi_in_index++);
				slv2_instance_connect_port(_instance, port_index,
				                           bufs.get_lv2_midi(true, buf_index).data());
			} else if (parameter_is_output(port_index)) {
				const uint32_t buf_index = out_map.get(DataType::MIDI, midi_out_index++);
				slv2_instance_connect_port(_instance, port_index,
				                           bufs.get_lv2_midi(false, buf_index).data());
			}
		} else if (!parameter_is_control(port_index)) {
			// Optional port (it'd better be if we've made it this far...)
			slv2_instance_connect_port(_instance, port_index, NULL);
		}
	}

	run(nframes);

	midi_out_index = 0;
	for (uint32_t port_index = 0; port_index < parameter_count(); ++port_index) {
		if (parameter_is_midi(port_index) && parameter_is_output(port_index)) {
			const uint32_t buf_index = out_map.get(DataType::MIDI, midi_out_index++);
			bufs.flush_lv2_midi(true, buf_index);
		}
	}

	cycles_t now = get_cycles();
	set_cycles((uint32_t)(now - then));

	return 0;
}

bool
LV2Plugin::parameter_is_control(uint32_t param) const
{
	SLV2Port port = slv2_plugin_get_port_by_index(_plugin, param);
	return slv2_port_is_a(_plugin, port, _world.control_class);
}

bool
LV2Plugin::parameter_is_audio(uint32_t param) const
{
	SLV2Port port = slv2_plugin_get_port_by_index(_plugin, param);
	return slv2_port_is_a(_plugin, port, _world.audio_class);
}

bool
LV2Plugin::parameter_is_midi(uint32_t param) const
{
	SLV2Port port = slv2_plugin_get_port_by_index(_plugin, param);
	return slv2_port_is_a(_plugin, port, _world.event_class);
	//	&& slv2_port_supports_event(_plugin, port, _world.midi_class);
}

bool
LV2Plugin::parameter_is_output(uint32_t param) const
{
	SLV2Port port = slv2_plugin_get_port_by_index(_plugin, param);
	return slv2_port_is_a(_plugin, port, _world.output_class);
}

bool
LV2Plugin::parameter_is_input(uint32_t param) const
{
	SLV2Port port = slv2_plugin_get_port_by_index(_plugin, param);
	return slv2_port_is_a(_plugin, port, _world.input_class);
}

void
LV2Plugin::print_parameter(uint32_t param, char* buf, uint32_t len) const
{
	if (buf && len) {
		if (param < parameter_count()) {
			snprintf(buf, len, "%.3f", get_parameter(param));
		} else {
			strcat(buf, "0");
		}
	}
}

void
LV2Plugin::run(pframes_t nframes)
{
	for (uint32_t i = 0; i < parameter_count(); ++i) {
		if (parameter_is_control(i) && parameter_is_input(i)) {
			_control_data[i] = _shadow_data[i];
		}
	}

	slv2_instance_run(_instance, nframes);
}

void
LV2Plugin::latency_compute_run()
{
	if (!_latency_control_port) {
		return;
	}

	// Run the plugin so that it can set its latency parameter

	activate();

	uint32_t port_index = 0;
	uint32_t in_index   = 0;
	uint32_t out_index  = 0;

	const framecnt_t bufsize = 1024;
	float            buffer[bufsize];

	memset(buffer, 0, sizeof(float) * bufsize);

	// FIXME: Ensure plugins can handle in-place processing

	port_index = 0;

	while (port_index < parameter_count()) {
		if (parameter_is_audio(port_index)) {
			if (parameter_is_input(port_index)) {
				slv2_instance_connect_port(_instance, port_index, buffer);
				in_index++;
			} else if (parameter_is_output(port_index)) {
				slv2_instance_connect_port(_instance, port_index, buffer);
				out_index++;
			}
		}
		port_index++;
	}

	run(bufsize);
	deactivate();
}

LV2World::LV2World()
	: world(slv2_world_new())
{
	slv2_world_load_all(world);
	input_class     = slv2_value_new_uri(world, SLV2_PORT_CLASS_INPUT);
	output_class    = slv2_value_new_uri(world, SLV2_PORT_CLASS_OUTPUT);
	control_class   = slv2_value_new_uri(world, SLV2_PORT_CLASS_CONTROL);
	audio_class     = slv2_value_new_uri(world, SLV2_PORT_CLASS_AUDIO);
	event_class     = slv2_value_new_uri(world, SLV2_PORT_CLASS_EVENT);
	midi_class      = slv2_value_new_uri(world, SLV2_EVENT_CLASS_MIDI);
	in_place_broken = slv2_value_new_uri(world, SLV2_NAMESPACE_LV2 "inPlaceBroken");
	integer         = slv2_value_new_uri(world, SLV2_NAMESPACE_LV2 "integer");
	toggled         = slv2_value_new_uri(world, SLV2_NAMESPACE_LV2 "toggled");
	srate           = slv2_value_new_uri(world, SLV2_NAMESPACE_LV2 "sampleRate");
	gtk_gui         = slv2_value_new_uri(world, NS_UI "GtkUI");
	external_gui    = slv2_value_new_uri(world, NS_UI "external");
	logarithmic     = slv2_value_new_uri(world, "http://lv2plug.in/ns/dev/extportinfo#logarithmic");
}

LV2World::~LV2World()
{
	slv2_value_free(input_class);
	slv2_value_free(output_class);
	slv2_value_free(control_class);
	slv2_value_free(audio_class);
	slv2_value_free(event_class);
	slv2_value_free(midi_class);
	slv2_value_free(in_place_broken);
}

LV2PluginInfo::LV2PluginInfo (void* lv2_world, void* slv2_plugin)
	: _lv2_world(lv2_world)
	, _slv2_plugin(slv2_plugin)
{
	type = ARDOUR::LV2;
}

LV2PluginInfo::~LV2PluginInfo()
{}

PluginPtr
LV2PluginInfo::load(Session& session)
{
	try {
		PluginPtr plugin;

		plugin.reset(new LV2Plugin(session.engine(), session,
		                           *(LV2World*)_lv2_world, (SLV2Plugin)_slv2_plugin,
		                           session.frame_rate()));

		plugin->set_info(PluginInfoPtr(new LV2PluginInfo(*this)));
		return plugin;
	} catch (failed_constructor& err) {
		return PluginPtr((Plugin*)0);
	}

	return PluginPtr();
}

PluginInfoList*
LV2PluginInfo::discover(void* lv2_world)
{
	PluginInfoList* plugs   = new PluginInfoList;
	LV2World*       world   = (LV2World*)lv2_world;
	SLV2Plugins     plugins = slv2_world_get_all_plugins(world->world);

	cerr << "LV2: Discovering " << slv2_plugins_size(plugins) << " plugins" << endl;

	for (unsigned i = 0; i < slv2_plugins_size(plugins); ++i) {
		SLV2Plugin       p = slv2_plugins_get_at(plugins, i);
		LV2PluginInfoPtr info(new LV2PluginInfo(lv2_world, p));

		SLV2Value name = slv2_plugin_get_name(p);

		if (!name) {
			cerr << "LV2: invalid plugin\n";
			continue;
		}

		info->type = LV2;

		info->name = string(slv2_value_as_string(name));
		slv2_value_free(name);

		SLV2PluginClass pclass = slv2_plugin_get_class(p);
		SLV2Value       label  = slv2_plugin_class_get_label(pclass);
		info->category = slv2_value_as_string(label);

		SLV2Value author_name = slv2_plugin_get_author_name(p);
		info->creator = author_name ? string(slv2_value_as_string(author_name)) : "Unknown";
		slv2_value_free(author_name);

		info->path = "/NOPATH"; // Meaningless for LV2

		info->n_inputs.set_audio(
			slv2_plugin_get_num_ports_of_class(
				p, world->input_class, world->audio_class, NULL));
		info->n_inputs.set_midi(
			slv2_plugin_get_num_ports_of_class(
				p, world->input_class, world->event_class, NULL));

		info->n_outputs.set_audio(
			slv2_plugin_get_num_ports_of_class(
				p, world->output_class, world->audio_class, NULL));
		info->n_outputs.set_midi(
			slv2_plugin_get_num_ports_of_class(
				p, world->output_class, world->event_class, NULL));

		info->unique_id = slv2_value_as_uri(slv2_plugin_get_uri(p));
		info->index     = 0; // Meaningless for LV2

		plugs->push_back(info);
	}

	cerr << "Done LV2 discovery" << endl;

	return plugs;
}