Merge branch 'settings'

36 files changed, 942 insertions, 1047 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index a1b1615..4d167af 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -13,7 +13,6 @@ EXTRA_DIST = \
 	channelmixer.h \
 	chresampler.h \
 	configfile.h \
-	configuration.h \
 	configparser.h \
 	cpp11fix.h \
 	drumgizmo.h \
@@ -24,13 +23,11 @@ EXTRA_DIST = \
 	instrument.h \
 	instrumentparser.h \
 	memchecker.h \
-	message.h \
-	messagehandler.h \
-	messagereceiver.h \
 	midimapparser.h \
 	midimapper.h \
 	mutex.h \
 	nolocale.h \
+	notifier.h \
 	path.h \
 	powerlist.h \
 	rangemap.h \
@@ -54,7 +51,6 @@ EXTRA_DIST = \
 	channelmixer.cc \
 	chresampler.cc \
 	configfile.cc \
-	configuration.cc \
 	configparser.cc \
 	drumgizmo.cc \
 	drumkit.cc \
@@ -64,8 +60,6 @@ EXTRA_DIST = \
 	instrument.cc \
 	instrumentparser.cc \
 	memchecker.cc \
-	messagehandler.cc \
-	messagereceiver.cc \
 	midimapparser.cc \
 	midimapper.cc \
 	mutex.cc \
diff --git a/src/Makefile.am.drumgizmo b/src/Makefile.am.drumgizmo
index 8f648d0..6fddded 100644
--- a/src/Makefile.am.drumgizmo
+++ b/src/Makefile.am.drumgizmo
@@ -11,7 +11,6 @@ DRUMGIZMO_SOURCES = \
 	$(top_srcdir)/src/channelmixer.cc \
 	$(top_srcdir)/src/chresampler.cc \
 	$(top_srcdir)/src/configfile.cc \
-	$(top_srcdir)/src/configuration.cc \
 	$(top_srcdir)/src/configparser.cc \
 	$(top_srcdir)/src/drumgizmo.cc \
 	$(top_srcdir)/src/drumkit.cc \
@@ -21,8 +20,6 @@ DRUMGIZMO_SOURCES = \
 	$(top_srcdir)/src/instrument.cc \
 	$(top_srcdir)/src/instrumentparser.cc \
 	$(top_srcdir)/src/memchecker.cc \
-	$(top_srcdir)/src/messagehandler.cc \
-	$(top_srcdir)/src/messagereceiver.cc \
 	$(top_srcdir)/src/midimapparser.cc \
 	$(top_srcdir)/src/midimapper.cc \
 	$(top_srcdir)/src/mutex.cc \
diff --git a/src/atomic.h b/src/atomic.h
new file mode 100644
index 0000000..95a5e9d
--- /dev/null
+++ b/src/atomic.h
@@ -0,0 +1,182 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/***************************************************************************
+ *            atomic.h
+ *
+ *  Wed Mar 23 09:15:05 CET 2016
+ *  Copyright 2016 Christian Glöckner
+ *  cgloeckner@freenet.de
+ ****************************************************************************/
+
+/*
+ *  This file is part of DrumGizmo.
+ *
+ *  DrumGizmo 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 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  DrumGizmo 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 DrumGizmo; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+ */
+#pragma once
+
+#include <type_traits>
+#include <atomic>
+
+#include <mutex>
+#include "mutex.h"
+
+template <typename T, typename = void>
+class Atomic;
+
+// use std::atomic if possible
+template <typename T>
+class Atomic<T, typename std::enable_if<std::is_pod<T>::value>::type>
+	: public std::atomic<T>
+{
+public:
+	// inherit methods
+	using std::atomic<T>::atomic;
+	using std::atomic<T>::operator=;
+};
+
+// else work around it using a mutex
+template <typename T>
+class Atomic<T, typename std::enable_if<!std::is_pod<T>::value>::type>
+{
+public:
+	using self_type =
+		Atomic<T, typename std::enable_if<!std::is_pod<T>::value>::type>;
+
+	Atomic()
+		: data{}
+		, mutex{}
+	{
+	}
+
+	Atomic(T data)
+		: data{std::move(data)}
+		, mutex{}
+	{
+	}
+
+	Atomic(self_type const & other)
+		: data{}
+		, mutex{}
+	{
+		std::lock_guard<std::mutex> lock{other.mutex};
+		data = other.data;
+	}
+
+	Atomic(self_type&& other)
+		: data{}
+		, mutex{}
+	{
+		std::lock_guard<std::mutex> lock{other.mutex};
+		std::swap(data, other.data);
+	}
+
+	T operator=(T data)
+	{
+		std::lock_guard<std::mutex> lock{mutex};
+		this->data = std::move(data);
+		return this->data;
+	}
+
+	operator T() const
+	{
+		return load();
+	}
+
+	bool is_lock_free() const
+	{
+		return false;
+	}
+
+	void store(T data)
+	{
+		std::lock_guard<std::mutex> lock{mutex};
+		this->data = std::move(data);
+	}
+
+	T load() const {
+		std::lock_guard<std::mutex> lock{mutex};
+		return data;
+	}
+
+	T exchange(T data){
+		std::lock_guard<std::mutex> lock{mutex};
+		std::swap(data, this->data);
+		return data;
+	}
+
+	bool operator==(const T& other) const
+	{
+		std::lock_guard<std::mutex> lock{mutex};
+		return other == data;
+	}
+
+	bool operator!=(const T& other) const
+	{
+		std::lock_guard<std::mutex> lock{mutex};
+		return !(other == data);
+	}
+
+	bool operator==(const Atomic<T>& other) const
+	{
+		std::lock_guard<std::mutex> lock{mutex};
+		return other.load() == data;
+	}
+
+	bool operator!=(const Atomic<T>& other) const
+	{
+		std::lock_guard<std::mutex> lock{mutex};
+		return !(other.load() == data);
+	}
+
+private:
+	T data;
+	mutable std::mutex mutex;
+};
+
+//! Getter utility class.
+template <typename T> class SettingRef
+{
+public:
+	SettingRef(Atomic<T>& value)
+		: value(value)
+	{
+		// string isn't lock free either
+		assert((std::is_same<T, std::string>::value || value.is_lock_free()));
+	}
+
+	bool hasChanged()
+	{
+		T tmp = cache;
+		cache.exchange(value);
+
+		if(firstAccess)
+		{
+			firstAccess = false;
+			return true;
+		}
+
+		return cache != tmp;
+	}
+
+	T getValue() const
+	{
+		return cache;
+	}
+
+private:
+	bool firstAccess{true};
+	Atomic<T>& value;
+	Atomic<T> cache;
+};
diff --git a/src/audiofile.cc b/src/audiofile.cc
index 58b248b..84329f8 100644
--- a/src/audiofile.cc
+++ b/src/audiofile.cc
@@ -36,8 +36,6 @@
 #include <sndfile.h>
 #include <hugin.hpp>
 
-#include "configuration.h"
-
 AudioFile::AudioFile(const std::string& filename, int filechannel)
 {
 	is_loaded = false;
diff --git a/src/configuration.cc b/src/configuration.cc
deleted file mode 100644
index 72f6e4a..0000000
--- a/src/configuration.cc
+++ /dev/null
@@ -1,38 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/***************************************************************************
- *            configuration.cc
- *
- *  Sat Oct  8 14:37:14 CEST 2011
- *  Copyright 2011 Bent Bisballe Nyeng
- *  deva@aasimon.org
- ****************************************************************************/
-
-/*
- *  This file is part of DrumGizmo.
- *
- *  DrumGizmo is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU Lesser General Public License as published by
- *  the Free Software Foundation; either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  DrumGizmo 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 Lesser General Public License for more details.
- *
- *  You should have received a copy of the GNU Lesser General Public License
- *  along with DrumGizmo; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
- */
-#include "configuration.h"
-
-bool Conf::enable_velocity_modifier = true;
-float Conf::velocity_modifier_falloff = 0.5;
-float Conf::velocity_modifier_weight = 0.25;
-
-bool Conf::enable_velocity_randomiser = false;
-float Conf::velocity_randomiser_weight = 0.1;
-
-int Conf::samplerate = 44100;
-
-bool Conf::enable_resampling = true;
diff --git a/src/configuration.h b/src/configuration.h
deleted file mode 100644
index 3adf525..0000000
--- a/src/configuration.h
+++ /dev/null
@@ -1,44 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/***************************************************************************
- *            configuration.h
- *
- *  Sat Oct  8 14:37:13 CEST 2011
- *  Copyright 2011 Bent Bisballe Nyeng
- *  deva@aasimon.org
- ****************************************************************************/
-
-/*
- *  This file is part of DrumGizmo.
- *
- *  DrumGizmo is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU Lesser General Public License as published by
- *  the Free Software Foundation; either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  DrumGizmo 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 Lesser General Public License for more details.
- *
- *  You should have received a copy of the GNU Lesser General Public License
- *  along with DrumGizmo; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
- */
-#ifndef __DRUMGIZMO_CONFIGURATION_H__
-#define __DRUMGIZMO_CONFIGURATION_H__
-
-namespace Conf {
-  extern bool enable_velocity_modifier;
-  extern float velocity_modifier_falloff;
-  extern float velocity_modifier_weight;
-
-  extern bool enable_velocity_randomiser;
-  extern float velocity_randomiser_weight;
-
-  extern int samplerate;
-
-  extern bool enable_resampling;
-};
-
-
-#endif/*__DRUMGIZMO_CONFIGURATION_H__*/
diff --git a/src/drumgizmo.cc b/src/drumgizmo.cc
index 853e93d..aa6be23 100644
--- a/src/drumgizmo.cc
+++ b/src/drumgizmo.cc
@@ -38,26 +38,27 @@
 #include <hugin.hpp>
 
 #include <config.h>
+#include <memory>
 
 #include "drumkitparser.h"
 #include "audioinputenginemidi.h"
-#include "configuration.h"
 #include "configparser.h"
 
 #include "nolocale.h"
 
-DrumGizmo::DrumGizmo(AudioOutputEngine *o, AudioInputEngine *i)
-	: MessageReceiver(MSGRCV_ENGINE)
-	, loader()
+DrumGizmo::DrumGizmo(Settings& settings,
+                     AudioOutputEngine *o, AudioInputEngine *i)
+	: loader(settings)
 	, oe(o)
 	, ie(i)
 	, framesize(0)
 	, freewheel(false)
 	, events{}
+	, settings(settings)
 {
 	is_stopping = false;
 	audioCache.init(10000); // start thread
-	
+
 	events.reserve(1000);
 }
 
@@ -68,9 +69,12 @@ DrumGizmo::~DrumGizmo()
 
 bool DrumGizmo::loadkit(std::string file)
 {
+	settings.drumkit_load_status.store(LoadStatus::Idle);
+
 	if(file == "")
 	{
-		return 1;
+		settings.drumkit_load_status.store(LoadStatus::Error);
+		return false;
 	}
 
 	DEBUG(drumgizmo, "loadkit(%s)\n", file.c_str());
@@ -81,27 +85,31 @@ bool DrumGizmo::loadkit(std::string file)
 	// Delete all Channels, Instruments, Samples and AudioFiles.
 	kit.clear();
 
-	DrumKitParser parser(kit);
+	settings.drumkit_load_status.store(LoadStatus::Loading);
+
+	DrumKitParser parser(settings, kit);
 	if(parser.parseFile(file))
 	{
 		ERR(drumgizmo, "Drumkit parser failed: %s\n", file.c_str());
+		settings.drumkit_load_status.store(LoadStatus::Error);
 		return false;
 	}
 
-	// Check if there is enough free RAM to load the drumkit.
-	if(!memchecker.enoughFreeMemory(kit))
-	{
-		printf("WARNING: "
-		       "There doesn't seem to be enough RAM available to load the kit.\n"
-		       "Trying to load it anyway...\n");
-	}
+	// TODO: Re-introduce when the code has been moved to the loader thread.
+	//// Check if there is enough free RAM to load the drumkit.
+	//if(!memchecker.enoughFreeMemory(kit))
+	//{
+	//	printf("WARNING: "
+	//	       "There doesn't seem to be enough RAM available to load the kit.\n"
+	//	       "Trying to load it anyway...\n");
+	//}
 
 	loader.loadKit(&kit);
 
 #ifdef WITH_RESAMPLER
 	for(int i = 0; i < MAX_NUM_CHANNELS; ++i)
 	{
-		resampler[i].setup(kit.getSamplerate(), Conf::samplerate);
+		resampler[i].setup(kit.getSamplerate(), settings.samplerate.load());
 	}
 #endif/*WITH_RESAMPLER*/
 
@@ -125,79 +133,6 @@ bool DrumGizmo::init()
 	return true;
 }
 
-void DrumGizmo::handleMessage(Message *msg)
-{
-	DEBUG(msg, "got message.");
-	switch(msg->type()) {
-	case Message::LoadDrumKit:
-		{
-			DEBUG(msg, "got LoadDrumKitMessage message.");
-			LoadDrumKitMessage *m = (LoadDrumKitMessage*)msg;
-			loadkit(m->drumkitfile);
-			//init(true);
-		}
-		break;
-	case Message::LoadMidimap:
-		DEBUG(msg, "got LoadMidimapMessage message.");
-		if(!ie->isMidiEngine())
-		{
-			break;
-		}
-		{
-			AudioInputEngineMidi *aim = (AudioInputEngineMidi*)ie;
-			LoadMidimapMessage *m = (LoadMidimapMessage*)msg;
-			bool ret = aim->loadMidiMap(m->midimapfile, kit.instruments);
-
-			LoadStatusMessageMidimap *ls = new LoadStatusMessageMidimap();
-			ls->success = ret;
-			msghandler.sendMessage(MSGRCV_UI, ls);
-		}
-		break;
-	case Message::EngineSettingsMessage:
-		{
-			bool mmap_loaded = false;
-			std::string mmapfile;
-			if(ie->isMidiEngine())
-			{
-				AudioInputEngineMidi *aim = (AudioInputEngineMidi*)ie;
-				mmapfile = aim->getMidimapFile();
-				mmap_loaded = aim->isValid();
-			}
-
-			EngineSettingsMessage *msg = new EngineSettingsMessage();
-			msg->midimapfile = mmapfile;
-			msg->midimap_loaded = mmap_loaded;
-			msg->drumkitfile = kit.getFile();
-			msg->drumkit_loaded = loader.isDone();
-			msg->enable_velocity_modifier = Conf::enable_velocity_modifier;
-			msg->velocity_modifier_falloff = Conf::velocity_modifier_falloff;
-			msg->velocity_modifier_weight = Conf::velocity_modifier_weight;
-			msg->enable_velocity_randomiser = Conf::enable_velocity_randomiser;
-			msg->velocity_randomiser_weight = Conf::velocity_randomiser_weight;
-			msghandler.sendMessage(MSGRCV_UI, msg);
-		}
-		break;
-	case Message::ChangeSettingMessage:
-		{
-			ChangeSettingMessage *ch = (ChangeSettingMessage*)msg;
-			switch(ch->name) {
-			case ChangeSettingMessage::enable_velocity_modifier:
-				Conf::enable_velocity_modifier = ch->value;
-				break;
-			case ChangeSettingMessage::velocity_modifier_weight:
-				Conf::velocity_modifier_weight = ch->value;
-				break;
-			case ChangeSettingMessage::velocity_modifier_falloff:
-				Conf::velocity_modifier_falloff = ch->value;
-				break;
-			}
-		}
-		break;
-	default:
-		break;
-	}
-}
-
 void DrumGizmo::setFrameSize(size_t framesize)
 {
 	// If we are resampling override the frame size.
@@ -259,8 +194,31 @@ bool DrumGizmo::run(size_t pos, sample_t *samples, size_t nsamples)
 {
 	setFrameSize(nsamples);
 
-	// Handle engine messages, at most one in each iteration:
-	handleMessages(1);
+	// TODO: Move this to DrumKitLoader thread.
+	if(getter.drumkit_file.hasChanged())
+	{
+		loadkit(getter.drumkit_file.getValue());
+	}
+
+	// TODO: Move this to DrumKitLoader thread.
+	if(getter.midimap_file.hasChanged())
+	{
+		auto ie_midi = dynamic_cast<AudioInputEngineMidi*>(ie);
+		if(ie_midi)
+		{
+			settings.midimap_load_status.store(LoadStatus::Loading);
+			bool ret = ie_midi->loadMidiMap(getter.midimap_file.getValue(),
+			                                kit.instruments);
+			if(ret)
+			{
+				settings.midimap_load_status.store(LoadStatus::Done);
+			}
+			else
+			{
+				settings.midimap_load_status.store(LoadStatus::Error);
+			}
+		}
+	}
 
 	ie->pre();
 	oe->pre(nsamples);
@@ -398,7 +356,7 @@ bool DrumGizmo::run(size_t pos, sample_t *samples, size_t nsamples)
 	// Write audio
 	//
 #ifdef WITH_RESAMPLER
-	if((Conf::enable_resampling == false) ||
+	if((settings.enable_resampling.load() == false) ||
 	   (resampler[0].getRatio() == 1.0)) // No resampling needed
 	{
 #endif
@@ -636,17 +594,17 @@ void DrumGizmo::stop()
 
 int DrumGizmo::samplerate()
 {
-	return Conf::samplerate;
+	return settings.samplerate.load();
 }
 
 void DrumGizmo::setSamplerate(int samplerate)
 {
 	DEBUG(dgeditor, "%s samplerate: %d\n", __PRETTY_FUNCTION__, samplerate);
-	Conf::samplerate = samplerate;
+	settings.samplerate.store(samplerate);
 #ifdef WITH_RESAMPLER
 	for(int i = 0; i < MAX_NUM_CHANNELS; ++i)
 	{
-		resampler[i].setup(kit.getSamplerate(), Conf::samplerate);
+		resampler[i].setup(kit.getSamplerate(), settings.samplerate.load());
 	}
 	if(resampler[0].getRatio() != 1)
 	{
@@ -691,15 +649,15 @@ std::string DrumGizmo::configString()
 		"  <value name=\"drumkitfile\">" + kit.getFile() + "</value>\n"
 		"  <value name=\"midimapfile\">" + mmapfile + "</value>\n"
 		"  <value name=\"enable_velocity_modifier\">" +
-		bool2str(Conf::enable_velocity_modifier) + "</value>\n"
+		bool2str(settings.enable_velocity_modifier.load()) + "</value>\n"
 		"  <value name=\"velocity_modifier_falloff\">" +
-		float2str(Conf::velocity_modifier_falloff) + "</value>\n"
+		float2str(settings.velocity_modifier_falloff.load()) + "</value>\n"
 		"  <value name=\"velocity_modifier_weight\">" +
-		float2str(Conf::velocity_modifier_weight) + "</value>\n"
+		float2str(settings.velocity_modifier_weight.load()) + "</value>\n"
 		"  <value name=\"enable_velocity_randomiser\">" +
-		bool2str(Conf::enable_velocity_randomiser) + "</value>\n"
+		bool2str(settings.enable_velocity_randomiser.load()) + "</value>\n"
 		"  <value name=\"velocity_randomiser_weight\">" +
-		float2str(Conf::velocity_randomiser_weight) + "</value>\n"
+		float2str(settings.velocity_randomiser_weight.load()) + "</value>\n"
 		"</config>";
 }
 
@@ -711,68 +669,50 @@ bool DrumGizmo::setConfigString(std::string cfg)
 	ConfigParser p;
 	if(p.parseString(cfg))
 	{
-	 ERR(drumgizmo, "Config parse error.\n");
-	 return false;
+		ERR(drumgizmo, "Config parse error.\n");
+		return false;
 	}
 
 	if(p.value("enable_velocity_modifier") != "")
 	{
-		Conf::enable_velocity_modifier =
-			p.value("enable_velocity_modifier") == "true";
+		settings.enable_velocity_modifier.store(p.value("enable_velocity_modifier") == "true");
 	}
 
 	if(p.value("velocity_modifier_falloff") != "")
 	{
-		Conf::velocity_modifier_falloff =
-			str2float(p.value("velocity_modifier_falloff"));
+		settings.velocity_modifier_falloff.store(str2float(p.value("velocity_modifier_falloff")));
 	}
 
 	if(p.value("velocity_modifier_weight") != "")
 	{
-		Conf::velocity_modifier_weight =
-			str2float(p.value("velocity_modifier_weight"));
+		settings.velocity_modifier_weight.store(str2float(p.value("velocity_modifier_weight")));
 	}
 
 	if(p.value("enable_velocity_randomiser") != "")
 	{
-		Conf::enable_velocity_randomiser =
-			p.value("enable_velocity_randomiser") == "true";
+		settings.enable_velocity_randomiser.store(p.value("enable_velocity_randomiser") == "true");
 	}
 
 	if(p.value("velocity_randomiser_weight") != "")
 	{
-		Conf::velocity_randomiser_weight =
-			str2float(p.value("velocity_randomiser_weight"));
+		settings.velocity_randomiser_weight.store(str2float(p.value("velocity_randomiser_weight")));
 	}
 
 	if(p.value("enable_resampling") != "")
 	{
-		Conf::enable_resampling =
-			p.value("enable_resampling") == "true";
+		settings.enable_resampling.store(p.value("enable_resampling") == "true");
 	}
 
 	std::string newkit = p.value("drumkitfile");
-	if(newkit != "" && kit.getFile() != newkit)
+	if(newkit != "")
 	{
-		/*
-		  if(!loadkit(p.values["drumkitfile"]))
-		  {
-		  return false;
-		  }
-		  init(true);
-		*/
-		LoadDrumKitMessage *msg = new LoadDrumKitMessage();
-		msg->drumkitfile = newkit;
-		msghandler.sendMessage(MSGRCV_ENGINE, msg);
+		settings.drumkit_file.store(newkit);
 	}
 
 	std::string newmidimap = p.value("midimapfile");
 	if(newmidimap != "")
 	{
-		//midimapfile = newmidimap;
-		LoadMidimapMessage *msg = new LoadMidimapMessage();
-		msg->midimapfile = newmidimap;
-		msghandler.sendMessage(MSGRCV_ENGINE, msg);
+		settings.midimap_file.store(newmidimap);
 	}
 
 	return true;
diff --git a/src/drumgizmo.h b/src/drumgizmo.h
index 632d5fc..7af5dbb 100644
--- a/src/drumgizmo.h
+++ b/src/drumgizmo.h
@@ -31,34 +31,26 @@
 
 #include "audiooutputengine.h"
 #include "audioinputengine.h"
-
 #include "events.h"
 #include "audiofile.h"
 #include "drumkit.h"
 #include "memchecker.h"
-
 #include "drumkitloader.h"
 #include "audiocache.h"
-
 #include "mutex.h"
-
-#include "message.h"
-
-#include "messagereceiver.h"
-
 #include "chresampler.h"
-
 #include "configfile.h"
+#include "settings.h"
 
 #define MAX_NUM_CHANNELS 64
 #define REFSFILE "refs.conf"
 #define RESAMPLER_INPUT_BUFFER 64
 
 class DrumGizmo
-	: public MessageReceiver
 {
 public:
-	DrumGizmo(AudioOutputEngine *outputengine, AudioInputEngine *inputengine);
+	DrumGizmo(Settings& settings,
+	          AudioOutputEngine *outputengine, AudioInputEngine *inputengine);
 	virtual ~DrumGizmo();
 
 	bool loadkit(std::string kitfile);
@@ -74,8 +66,6 @@ public:
 	std::string configString();
 	bool setConfigString(std::string cfg);
 
-	void handleMessage(Message *msg);
-
 	int samplerate();
 	void setSamplerate(int samplerate);
 
@@ -106,6 +96,8 @@ protected:
 
 	size_t framesize;
 	bool freewheel;
-	
+
 	std::vector<event_t> events;
+	Settings& settings;
+	SettingsGetter getter{settings};
 };
diff --git a/src/drumkit.cc b/src/drumkit.cc
index 1b95c87..f25a6ea 100644
--- a/src/drumkit.cc
+++ b/src/drumkit.cc
@@ -39,12 +39,11 @@ DrumKit::~DrumKit()
 
 void DrumKit::clear()
 {
-	Instruments::iterator i = instruments.begin();
-	while(i != instruments.end())
+	for(auto& instrument : instruments)
 	{
-		delete *i;
-		i++;
+		delete instrument;
 	}
+
 	instruments.clear();
 
 	channels.clear();
@@ -78,20 +77,3 @@ size_t DrumKit::getSamplerate() const
 {
 	return _samplerate;
 }
-
-#ifdef TEST_DRUMKIT
-// Additional dependency files
-// deps:
-// Required cflags (autoconf vars may be used)
-// cflags:
-// Required link options (autoconf vars may be used)
-// libs:
-#include "test.h"
-
-TEST_BEGIN;
-
-// TODO: Put some testcode here (see test.h for usable macros).
-
-TEST_END;
-
-#endif /*TEST_DRUMKIT*/
diff --git a/src/drumkit.h b/src/drumkit.h
index 1ceef3e..e3ae783 100644
--- a/src/drumkit.h
+++ b/src/drumkit.h
@@ -33,11 +33,9 @@
 #include "instrument.h"
 #include "versionstr.h"
 
-class DrumKitParser;
 class DrumKit
 {
 	friend class DrumKitParser;
-
 public:
 	DrumKit();
 	~DrumKit();
diff --git a/src/drumkitloader.cc b/src/drumkitloader.cc
index ff489ea..3a0e096 100644
--- a/src/drumkitloader.cc
+++ b/src/drumkitloader.cc
@@ -26,14 +26,17 @@
  */
 #include "drumkitloader.h"
 
+#include <iostream>
+
 #include <hugin.hpp>
 
 #include "drumkitparser.h"
 #include "drumgizmo.h"
 
-DrumKitLoader::DrumKitLoader()
-	: semaphore("drumkitloader")
-	, framesize(0)
+DrumKitLoader::DrumKitLoader(Settings& settings)
+	: framesize(0)
+	, settings(settings)
+	, getter(settings)
 {
 	run();
 	run_semaphore.wait(); // Wait for the thread to actually start.
@@ -55,7 +58,7 @@ DrumKitLoader::~DrumKitLoader()
 void DrumKitLoader::stop()
 {
 	{
-		MutexAutolock l(mutex);
+		std::lock_guard<std::mutex> guard(mutex);
 		load_queue.clear();
 	}
 
@@ -66,68 +69,48 @@ void DrumKitLoader::stop()
 
 void DrumKitLoader::skip()
 {
-	MutexAutolock l(mutex);
+	std::lock_guard<std::mutex> guard(mutex);
 	load_queue.clear();
 }
 
 void DrumKitLoader::setFrameSize(size_t framesize)
 {
-	DEBUG(loader, "%s pre\n", __PRETTY_FUNCTION__);
-
-	{
-		MutexAutolock l(mutex);
-		this->framesize = framesize;
-		framesize_semaphore.post(); // Signal that the framesize has been set.
-	}
-
-	DEBUG(loader, "%s post\n", __PRETTY_FUNCTION__);
+	std::lock_guard<std::mutex> guard(mutex);
+	this->framesize = framesize;
+	framesize_semaphore.post(); // Signal that the framesize has been set.
 }
 
 bool DrumKitLoader::isDone()
 {
-	MutexAutolock l(mutex);
+	std::lock_guard<std::mutex> guard(mutex);
 	return load_queue.size() == 0;
 }
 
 void DrumKitLoader::loadKit(DrumKit *kit)
 {
-	MutexAutolock l(mutex);
+	std::lock_guard<std::mutex> guard(mutex);
 
 	DEBUG(loader, "Create AudioFile queue from DrumKit\n");
 
-	total_num_audiofiles = 0;// For UI Progress Messages
-
-	{ // Count total number of files that need loading:
-		Instruments::iterator i = kit->instruments.begin();
-		while(i != kit->instruments.end())
-		{
-			Instrument *instr = *i;
-			total_num_audiofiles += instr->audiofiles.size();
-			++i;
-		}
-	}
+	std::size_t total_num_audiofiles = 0;// For UI Progress Messages
 
-	fraction = total_num_audiofiles / 200;
-	if(fraction == 0)
+	// Count total number of files that need loading:
+	for(auto instr : kit->instruments)
 	{
-		fraction = 1;
+		total_num_audiofiles += instr->audiofiles.size();
 	}
 
-	{ // Now actually queue them for loading:
-		Instruments::iterator i = kit->instruments.begin();
-		while(i != kit->instruments.end())
-		{
-			Instrument *instr = *i;
-
-			std::vector<AudioFile*>::iterator af = instr->audiofiles.begin();
-			while(af != instr->audiofiles.end())
-			{
-				AudioFile *audiofile = *af;
-				load_queue.push_back(audiofile);
-				af++;
-			}
+	settings.number_of_files.store(total_num_audiofiles);
 
-			++i;
+	// Now actually queue them for loading:
+	for(auto instr : kit->instruments)
+	{
+		std::vector<AudioFile*>::iterator af = instr->audiofiles.begin();
+		while(af != instr->audiofiles.end())
+		{
+			AudioFile *audiofile = *af;
+			load_queue.push_back(audiofile);
+			af++;
 		}
 	}
 
@@ -151,23 +134,35 @@ void DrumKitLoader::thread_main()
 	{
 		size_t size;
 		{
-			MutexAutolock l(mutex);
+			std::lock_guard<std::mutex> guard(mutex);
 			size = load_queue.size();
 		}
 
 		// Only sleep if queue is empty.
 		if(size == 0)
 		{
-			semaphore.wait();
+			semaphore.wait(std::chrono::milliseconds(1000));
+		}
+
+		if(getter.drumkit_file.hasChanged())
+		{
+			//std::cout << "RELOAD DRUMKIT!" << std::endl;
+		}
+
+		if(getter.midimap_file.hasChanged())
+		{
+			//std::cout << "RELOAD MIDIMAP!" << std::endl;
 		}
 
 		std::string filename;
 		{
-			MutexAutolock l(mutex);
+			std::lock_guard<std::mutex> guard(mutex);
+
 			if(load_queue.size() == 0)
 			{
 				continue;
 			}
+
 			AudioFile *audiofile = load_queue.front();
 			load_queue.pop_front();
 			filename = audiofile->filename;
@@ -183,15 +178,13 @@ void DrumKitLoader::thread_main()
 			audiofile->load(preload_size);
 		}
 
-		loaded++;
+		++loaded;
+
+		settings.number_of_files_loaded.store(loaded);
 
-		if(loaded % fraction == 0 || loaded == total_num_audiofiles)
+		if(settings.number_of_files.load() == loaded)
 		{
-			LoadStatusMessage *ls = new LoadStatusMessage();
-			ls->number_of_files = total_num_audiofiles;
-			ls->numer_of_files_loaded = loaded;
-			ls->current_file = filename;
-			msghandler.sendMessage(MSGRCV_UI, ls);
+			settings.drumkit_load_status.store(LoadStatus::Done);
 		}
 	}
 
diff --git a/src/drumkitloader.h b/src/drumkitloader.h
index 3656839..3fd7ec1 100644
--- a/src/drumkitloader.h
+++ b/src/drumkitloader.h
@@ -28,12 +28,14 @@
 
 #include <string>
 #include <list>
+#include <mutex>
+#include "mutex.h"
 
 #include "thread.h"
 #include "semaphore.h"
-#include "mutex.h"
 
 #include "drumkit.h"
+#include "settings.h"
 
 //! This class is responsible for loading the drumkits in its own thread.
 //! All interaction calls are simply modifying queues and not doing any
@@ -45,7 +47,7 @@ class DrumKitLoader
 {
 public:
 	//! The constrcutor starts the loader thread.
-	DrumKitLoader();
+	DrumKitLoader(Settings& settings);
 
 	//! The destructor signals the thread to stop and waits to merge before
 	//! returning (ie. deleting the object will garantuee that the thread has
@@ -75,11 +77,11 @@ protected:
 	Semaphore run_semaphore;
 	Semaphore semaphore;
 	Semaphore framesize_semaphore;
-	Mutex mutex;
+	std::mutex mutex;
 	volatile bool running{false};
 	std::list<AudioFile*> load_queue;
-	size_t total_num_audiofiles{0};
-	size_t fraction{1};
-	size_t loaded{0};
-	size_t framesize{0};
+	std::size_t loaded{0};
+	std::size_t framesize{0};
+	Settings& settings;
+	SettingsGetter getter;
 };
diff --git a/src/drumkitparser.cc b/src/drumkitparser.cc
index 3ba69c8..048a05b 100644
--- a/src/drumkitparser.cc
+++ b/src/drumkitparser.cc
@@ -34,9 +34,10 @@
 #include "path.h"
 #include "drumgizmo.h"
 
-DrumKitParser::DrumKitParser(DrumKit& kit)
-	: kit(kit)
- 	, refs(REFSFILE)
+DrumKitParser::DrumKitParser(Settings& settings, DrumKit& k)
+	: kit(k)
+	, refs(REFSFILE)
+	, settings(settings)
 {
 }
 
@@ -46,9 +47,9 @@ int DrumKitParser::parseFile(const std::string& filename)
 
 	if(refs.load())
 	{
-		if(filename.size() > 1 && filename[0] == '@')
+		if((filename.size() > 1) && (filename[0] == '@'))
 		{
-			edited_filename	= refs.getValue(filename.substr(1));
+			edited_filename = refs.getValue(filename.substr(1));
 		}
 	}
 	else
@@ -57,9 +58,10 @@ int DrumKitParser::parseFile(const std::string& filename)
 	}
 
 	path = getPath(edited_filename);
-	auto result = SAXParser::parseFile(filename);
+	auto result = SAXParser::parseFile(edited_filename);
 
-	if (result == 0) {
+	if(result == 0)
+	{
 		kit._file = edited_filename;
 	}
 
@@ -101,7 +103,7 @@ void DrumKitParser::startTag(const std::string& name, const attr_t& attr)
 			{
 				ERR(kitparser, "Error parsing version number: %s, using 1.0\n", err);
 				kit._version = VersionStr(1,0,0);
-			} 
+			}
 		}
 		else
 		{
@@ -112,7 +114,7 @@ void DrumKitParser::startTag(const std::string& name, const attr_t& attr)
 
 	if(name == "channels")
 	{
-	
+
 	}
 
 	if(name == "channel")
@@ -140,6 +142,7 @@ void DrumKitParser::startTag(const std::string& name, const attr_t& attr)
 			ERR(kitparser, "Missing name in instrument tag.\n");
 			return;
 		}
+
 		if(attr.find("file") == attr.end())
 		{
 			ERR(kitparser, "Missing file in instrument tag.\n");
@@ -180,12 +183,14 @@ void DrumKitParser::endTag(const std::string& name)
 {
 	if(name == "instrument")
 	{
-		Instrument* i = new Instrument();
-		i->setGroup(instr_group);
-		//    Instrument &i = kit.instruments[kit.instruments.size() - 1];
-		InstrumentParser parser(*i);
+		Instrument* instrument = new Instrument(settings);
+		instrument->setGroup(instr_group);
+
+		InstrumentParser parser(*instrument);
 		parser.parseFile(path + "/" + instr_file);
-		kit.instruments.push_back(i);
+
+		// Transfer ownership to the DrumKit object.
+		kit.instruments.push_back(instrument);
 
 		// Assign kit channel numbers to instruments channels.
 		std::vector<InstrumentChannel*>::iterator ic = parser.channellist.begin();
@@ -206,16 +211,18 @@ void DrumKitParser::endTag(const std::string& name)
 					c->num = kit.channels[cnt].num;
 				}
 			}
+
 			if(c->num == NO_CHANNEL)
 			{
 				ERR(kitparser, "Missing channel '%s' in instrument '%s'\n",
-				      c->name.c_str(), i->getName().c_str());
+				      c->name.c_str(), instrument->getName().c_str());
 			}
-			else {
+			else
+			{
 				/*
-				   DEBUG(kitparser, "Assigned channel '%s' to number %d in instrument '%s'\n",
-				   c->name.c_str(), c->num, i.name().c_str());
-				   */
+				  DEBUG(kitparser, "Assigned channel '%s' to number %d in instrument '%s'\n",
+				  c->name.c_str(), c->num, i.name().c_str());
+				*/
 			}
 			ic++;
 		}
diff --git a/src/drumkitparser.h b/src/drumkitparser.h
index b0c8d8f..0adccb9 100644
--- a/src/drumkitparser.h
+++ b/src/drumkitparser.h
@@ -34,7 +34,7 @@ class DrumKitParser
 	: public SAXParser
 {
 public:
-	DrumKitParser(DrumKit& kit);
+	DrumKitParser(Settings& setting, DrumKit& kit);
 
 	virtual int parseFile(const std::string& filename) override;
 
@@ -52,4 +52,5 @@ private:
 	std::string instr_group;
 
 	ConfigFile refs;
+	Settings& settings;
 };
diff --git a/src/instrument.cc b/src/instrument.cc
index 9f18233..cc052e9 100644
--- a/src/instrument.cc
+++ b/src/instrument.cc
@@ -26,15 +26,12 @@
  */
 #include "instrument.h"
 
-#include <stdlib.h>
-#include <stdio.h>
-
 #include <hugin.hpp>
 
 #include "sample.h"
-#include "configuration.h"
 
-Instrument::Instrument()
+Instrument::Instrument(Settings& settings)
+	: settings(settings)
 {
 	DEBUG(instrument, "new %p\n", this);
 	mod = 1.0;
@@ -45,7 +42,7 @@ Instrument::Instrument()
 
 Instrument::~Instrument()
 {
-	magic = NULL;
+	magic = nullptr;
 
 	DEBUG(instrument, "delete %p\n", this);
 	std::vector<AudioFile*>::iterator i = audiofiles.begin();
@@ -63,16 +60,26 @@ bool Instrument::isValid() const
 
 Sample* Instrument::sample(level_t level, size_t pos)
 {
-	Sample *sample = NULL;
+	// Read out all values from settings.
+	auto enable_velocity_randomiser = settings.enable_velocity_randomiser.load();
+	auto velocity_randomiser_weight = settings.velocity_randomiser_weight.load();
+	auto samplerate = settings.samplerate.load();
+	auto velocity_modifier_falloff = settings.velocity_modifier_falloff.load();
+	auto enable_velocity_modifier = settings.enable_velocity_modifier.load();
+	auto velocity_modifier_weight = settings.velocity_modifier_weight.load();
+
+	Sample *sample = nullptr;
 
-	if(Conf::enable_velocity_modifier == false) {
+	if(enable_velocity_modifier == false)
+	{
 		mod = 1.0;
 		lastpos = 0;
 	}
 
-	if(Conf::enable_velocity_randomiser) {
-		float r = rand.floatInRange(-1.0*Conf::velocity_randomiser_weight,
-					    Conf::velocity_randomiser_weight);
+	if(enable_velocity_randomiser)
+	{
+		float r = rand.floatInRange(-1.0 * velocity_randomiser_weight,
+		                            velocity_randomiser_weight);
 		level += r;
 		if(level > 1.0)
 		{
@@ -84,9 +91,9 @@ Sample* Instrument::sample(level_t level, size_t pos)
 		}
 	}
 
-	if(Conf::enable_velocity_modifier) {
-		mod += (pos - lastpos) /
-			(Conf::samplerate * Conf::velocity_modifier_falloff);
+	if(enable_velocity_modifier)
+	{
+		mod += (pos - lastpos) / (samplerate * velocity_modifier_falloff);
 		if(mod > 1.0)
 		{
 			mod = 1.0;
@@ -98,21 +105,22 @@ Sample* Instrument::sample(level_t level, size_t pos)
 		// Version 2.0
 		sample = powerlist.get(level * mod);
 	}
-	else {
+	else
+	{
 		// Version 1.0
 		std::vector<Sample*> s = samples.get(level * mod);
 		if(s.size() == 0)
 		{
-			return NULL;
+			return nullptr;
 		}
 
 		sample = rand.choose(s);
 	}
 
-	if(Conf::enable_velocity_modifier)
+	if(enable_velocity_modifier)
 	{
 		lastpos = pos;
-		mod *= Conf::velocity_modifier_weight;
+		mod *= velocity_modifier_weight;
 	}
 
 	return sample;
@@ -157,41 +165,3 @@ void Instrument::setGroup(const std::string& g)
 {
 	_group = g;
 }
-
-#ifdef TEST_INSTRUMENT
-// deps: channel.cc sample.cc audiofile.cc
-// cflags: $(SNDFILE_CFLAGS)
-// libs: $(SNDFILE_LIBS)
-#include "test.h"
-
-TEST_BEGIN;
-
-Instrument i("test");
-
-Sample* a = new Sample();
-i.addSample(0.0, 1.0, a);
-
-Sample* b = new Sample();
-i.addSample(0.0, 1.0, b);
-
-Sample* c = new Sample();
-i.addSample(1.5, 1.7, c);
-
-TEST_EQUAL(i.sample(0.0), b, "?");
-TEST_EQUAL(i.sample(0.0), a, "?");
-TEST_EQUAL(i.sample(0.0), b, "?");
-TEST_EQUAL(i.sample(0.0), b, "?");
-TEST_EQUAL(i.sample(0.0), b, "?");
-TEST_EQUAL(i.sample(0.0), b, "?");
-TEST_EQUAL(i.sample(0.0), a, "?");
-TEST_EQUAL(i.sample(0.0), a, "?");
-
-TEST_EQUAL(i.sample(2.0), NULL, "?");
-
-TEST_EQUAL(i.sample(1.6), c, "?");
-TEST_EQUAL(i.sample(1.6), c, "?");
-TEST_EQUAL(i.sample(1.6), c, "?");
-
-TEST_END;
-
-#endif /*TEST_INSTRUMENT*/
diff --git a/src/instrument.h b/src/instrument.h
index de5546b..a531aec 100644
--- a/src/instrument.h
+++ b/src/instrument.h
@@ -36,13 +36,13 @@
 #include "versionstr.h"
 #include "random.h"
 
-class InstrumentParser;
+#include "settings.h"
+
 class Instrument
 {
 	friend class InstrumentParser;
-
 public:
-	Instrument();
+	Instrument(Settings& settings);
 	~Instrument();
 
 	Sample* sample(level_t level, size_t pos);
@@ -78,7 +78,7 @@ private:
 
 	size_t lastpos;
 	float mod;
-
+	Settings& settings;
 	Random rand;
 };
 
diff --git a/src/instrumentparser.cc b/src/instrumentparser.cc
index 268f8f3..1e42cc3 100644
--- a/src/instrumentparser.cc
+++ b/src/instrumentparser.cc
@@ -35,8 +35,8 @@
 
 #include "nolocale.h"
 
-InstrumentParser::InstrumentParser(Instrument& i)
-	: instrument(i)
+InstrumentParser::InstrumentParser(Instrument& instrument)
+	: instrument(instrument)
 {
 
 }
@@ -64,14 +64,15 @@ void InstrumentParser::startTag(const std::string& name, const attr_t& attr)
 
 		if(attr.find("version") != attr.end())
 		{
-			try {
+			try
+			{
 				instrument.version = VersionStr(attr.at("version"));
 			}
-			catch(const char *err)
+			catch(const char* err)
 			{
 				ERR(instrparser, "Error parsing version number: %s, using 1.0\n", err);
 				instrument.version = VersionStr(1,0,0);
-			} 
+			}
 		}
 		else
 		{
@@ -82,7 +83,6 @@ void InstrumentParser::startTag(const std::string& name, const attr_t& attr)
 
 	if(name == "samples")
 	{
-
 	}
 
 	if(name == "sample")
@@ -93,10 +93,10 @@ void InstrumentParser::startTag(const std::string& name, const attr_t& attr)
 			return;
 		}
 
-		float power; 
+		float power;
 		if(attr.find("power") == attr.end())
 		{
-			power = -1; 
+			power = -1;
 		}
 		else
 		{
@@ -105,12 +105,12 @@ void InstrumentParser::startTag(const std::string& name, const attr_t& attr)
 		}
 
 		// TODO get rid of new or delete it properly
-		s = new Sample(attr.at("name"), power);
+		sample = new Sample(attr.at("name"), power);
 	}
 
 	if(name == "audiofile")
 	{
-		if(s == nullptr)
+		if(sample == nullptr)
 		{
 			ERR(instrparser,"Missing Sample!\n");
 			return;
@@ -139,18 +139,24 @@ void InstrumentParser::startTag(const std::string& name, const attr_t& attr)
 			}
 		}
 
-		filechannel = filechannel - 1; // 1-based in file, but zero-based internally
-		// TODO do those next two lines correspond with proper deletes? If not fix it.
-		AudioFile *af = new AudioFile(path + "/" + attr.at("file"), filechannel);
-		InstrumentChannel *ch = new InstrumentChannel(attr.at("channel"));
-		channellist.push_back(ch);
-		s->addAudioFile(ch, af);
-		instrument.audiofiles.push_back(af);
+		filechannel = filechannel - 1; // 1-based in file but zero-based internally.
+
+		AudioFile *audio_file =
+			new AudioFile(path + "/" + attr.at("file"), filechannel);
+
+		// TODO: This is not deleted anywhere...
+		InstrumentChannel *instrument_channel =
+			new InstrumentChannel(attr.at("channel"));
+
+		channellist.push_back(instrument_channel);
+		sample->addAudioFile(instrument_channel, audio_file);
+
+		// Transfer audio_file ownership to the instrument.
+		instrument.audiofiles.push_back(audio_file);
 	}
 
 	if(name == "velocities")
 	{
-
 	}
 
 	if(name == "velocity")
@@ -179,19 +185,17 @@ void InstrumentParser::startTag(const std::string& name, const attr_t& attr)
 			return;
 		}
 
-		Sample* sample = nullptr;
-		std::vector<Sample *>::iterator i = instrument.samplelist.begin();
-		while(i != instrument.samplelist.end())
+		Sample* sample_ref = nullptr;
+		for(auto& sample : instrument.samplelist)
 		{
-			if((*i)->name == attr.at("name"))
+			if(sample->name == attr.at("name"))
 			{
-				sample = *i;
+				sample_ref = sample;
 				break;
 			}
-			i++;
 		}
 
-		if(sample == nullptr)
+		if(sample_ref == nullptr)
 		{
 			ERR(instrparser,"Samplref pointed at non-existing sample.\n");
 			return;
@@ -200,7 +204,7 @@ void InstrumentParser::startTag(const std::string& name, const attr_t& attr)
 		if(instrument.version == VersionStr("1.0"))
 		{
 			// Old "velocity group" algorithm needs this
-			instrument.addSample(lower, upper, sample);
+			instrument.addSample(lower, upper, sample_ref);
 		}
 	}
 }
@@ -209,15 +213,15 @@ void InstrumentParser::endTag(const std::string& name)
 {
 	if(name == "sample")
 	{
-		if(s == nullptr)
+		if(sample == nullptr)
 		{
 			ERR(instrparser,"Missing Sample.\n");
 			return;
 		}
 
-		instrument.samplelist.push_back(s);
+		instrument.samplelist.push_back(sample);
 
-		s = nullptr;
+		sample = nullptr;
 	}
 
 	if(name == "instrument") {
diff --git a/src/instrumentparser.h b/src/instrumentparser.h
index 965694a..6cbaf8a 100644
--- a/src/instrumentparser.h
+++ b/src/instrumentparser.h
@@ -47,7 +47,7 @@ protected:
 
 private:
 	Instrument& instrument;
-	Sample* s{nullptr};
+	Sample* sample{nullptr};
 
 	std::string path;
 
diff --git a/src/message.h b/src/message.h
deleted file mode 100644
index 71d0da6..0000000
--- a/src/message.h
+++ /dev/null
@@ -1,121 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/***************************************************************************
- *            message.h
- *
- *  Wed Mar 20 15:50:57 CET 2013
- *  Copyright 2013 Bent Bisballe Nyeng
- *  deva@aasimon.org
- ****************************************************************************/
-
-/*
- *  This file is part of DrumGizmo.
- *
- *  DrumGizmo is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU Lesser General Public License as published by
- *  the Free Software Foundation; either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  DrumGizmo 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 Lesser General Public License for more details.
- *
- *  You should have received a copy of the GNU Lesser General Public License
- *  along with DrumGizmo; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
- */
-#ifndef __DRUMGIZMO_MESSAGE_H__
-#define __DRUMGIZMO_MESSAGE_H__
-
-#include <string>
-
-class MessageHandler;
-
-class Message {
-public:
-  typedef enum {
-    // Engine -> GUI Messages:
-    LoadStatus, // Signal GUI the current load status.
-    LoadStatusMidimap, // Signal GUI the current load status of the midimap.
-
-    // GUI -> Engine, Engine -> Engine Messages:
-    LoadDrumKit, // Signal engine to load drumkit.
-    LoadMidimap, // Signal engine to load midimap.
-    EngineSettingsMessage, // Request or receive engine settings.
-    ChangeSettingMessage, // Update named setting in engine.
-  } type_t;
-
-  typedef enum {
-    NormalProcessing, // Just add to the queue
-    FilterMultiple, // Ignore top message if it has the same type.
-    // SyncWait, // Block the send call until the message has been handled by the receiver.
-  } processing_mode_t;
-
-  virtual ~Message() {}
-  virtual type_t type() = 0;
-  virtual processing_mode_t processing_mode() { return NormalProcessing; }
-};
-
-class LoadStatusMessage : public Message {
-public:
-  type_t type() { return Message::LoadStatus; }
-  processing_mode_t processing_mode() { return FilterMultiple; }
-  unsigned int number_of_files;
-  unsigned int numer_of_files_loaded;
-  std::string current_file;
-};
-
-class LoadStatusMessageMidimap : public Message {
-public:
-  type_t type() { return Message::LoadStatusMidimap; }
-  bool success;
-};
-
-class LoadDrumKitMessage : public Message {
-public:
-  type_t type() { return Message::LoadDrumKit; }
-  std::string drumkitfile;
-};
-
-class LoadMidimapMessage : public Message {
-public:
-  type_t type() { return Message::LoadMidimap; }
-  std::string midimapfile;
-};
-
-class EngineSettingsMessage : public Message {
-public:
-  type_t type() { return Message::EngineSettingsMessage; }
-  std::string midimapfile;
-  bool midimap_loaded;
-
-  std::string drumkitfile;
-  bool drumkit_loaded;
-
-  float enable_velocity_modifier;
-  float velocity_modifier_falloff;
-  float velocity_modifier_weight;
-  float enable_velocity_randomiser;
-  float velocity_randomiser_weight;
-};
-
-class ChangeSettingMessage : public Message {
-public:
-  typedef enum {
-    enable_velocity_modifier,
-    velocity_modifier_weight,
-    velocity_modifier_falloff,
-  } setting_name_t;
-
-  ChangeSettingMessage(setting_name_t n, float v) {
-    name = n;
-    value = v;
-  }
-
-  type_t type() { return Message::ChangeSettingMessage; }
-
-  setting_name_t name;
-  float value;
-};
-
-#endif/*__DRUMGIZMO_MESSAGE_H__*/
diff --git a/src/messagehandler.cc b/src/messagehandler.cc
deleted file mode 100644
index 7a0c7ea..0000000
--- a/src/messagehandler.cc
+++ /dev/null
@@ -1,89 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/***************************************************************************
- *            messagehandler.cc
- *
- *  Fri Jun 14 20:30:43 CEST 2013
- *  Copyright 2013 Bent Bisballe Nyeng
- *  deva@aasimon.org
- ****************************************************************************/
-
-/*
- *  This file is part of DrumGizmo.
- *
- *  DrumGizmo is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU Lesser General Public License as published by
- *  the Free Software Foundation; either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  DrumGizmo 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 Lesser General Public License for more details.
- *
- *  You should have received a copy of the GNU Lesser General Public License
- *  along with DrumGizmo; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
- */
-#include "messagehandler.h"
-
-#include <hugin.hpp>
-
-#include "messagereceiver.h"
-
-// Global messagehandler:
-MessageHandler msghandler;
-
-MessageHandler::MessageHandler()
-{
-}
-
-void MessageHandler::addReceiver(message_receiver_id_t id,
-                                 MessageReceiver *receiver)
-{
-  MutexAutolock l(mutex);
-
-  receivers[id] = receiver;
-}
-
-void MessageHandler::removeReceiver(MessageReceiver *receiver)
-{
-  MutexAutolock l(mutex);
-
-  std::map<message_receiver_id_t, MessageReceiver *>::iterator i =
-    receivers.begin();
-  while(i != receivers.end()) {
-    if(i->second == receiver) {
-      receivers.erase(i);
-      break;
-    }
-    i++;
-  }
-}
-
-bool MessageHandler::sendMessage(message_receiver_id_t id, Message* msg)
-{
-  MutexAutolock l(mutex);
-
-  if(receivers.find(id) == receivers.end()) {
-    //WARN(msghandler, "Could not find id %d\n", id);
-    delete msg;
-    return false;
-  }
-
-  //DEBUG(msghandler, "Sending message to id %d\n", id);
-
-  MessageReceiver *receiver = receivers[id];
-  /* // This code causes sporadic segfaults on windows.
-  if(msg->processing_mode() == Message::FilterMultiple) {
-    Message *pmsg;
-    MutexAutolock lock(receiver->message_mutex); // Make peek/receive atomic.
-    while( (pmsg = receiver->peekMessage()) != NULL) {
-      if(pmsg->type() != msg->type()) break;
-      // Remove all old messages with same type.
-      delete receiver->receiveMessage();
-    }
-  }
-  */
-  receiver->sendMessage(msg);
-  return true;
-}
diff --git a/src/messagehandler.h b/src/messagehandler.h
deleted file mode 100644
index 2b6c40e..0000000
--- a/src/messagehandler.h
+++ /dev/null
@@ -1,66 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/***************************************************************************
- *            messagehandler.h
- *
- *  Fri Jun 14 20:30:43 CEST 2013
- *  Copyright 2013 Bent Bisballe Nyeng
- *  deva@aasimon.org
- ****************************************************************************/
-
-/*
- *  This file is part of DrumGizmo.
- *
- *  DrumGizmo is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU Lesser General Public License as published by
- *  the Free Software Foundation; either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  DrumGizmo 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 Lesser General Public License for more details.
- *
- *  You should have received a copy of the GNU Lesser General Public License
- *  along with DrumGizmo; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
- */
-#ifndef __DRUMGIZMO_MESSAGEHANDLER_H__
-#define __DRUMGIZMO_MESSAGEHANDLER_H__
-
-#include <map>
-
-#include "message.h"
-#include "mutex.h"
-
-typedef enum {
-  MSGRCV_ENGINE = 1,
-  MSGRCV_UI = 2,
-  MSGRCV_LOADER = 3,
-} message_receiver_id_t;
-
-class MessageReceiver;
-
-class MessageHandler {
-public:
-  MessageHandler();
-
-  void addReceiver(message_receiver_id_t id, MessageReceiver *receiver);
-  void removeReceiver(MessageReceiver *receiver);
-
-  /**
-   * Send Message to receiver with specified id.
-   * @return Return true if id is registered. Return false if id is not
-   * currently registered.
-   */
-  bool sendMessage(message_receiver_id_t id, Message* msg);
-
-private:
-  std::map<message_receiver_id_t, MessageReceiver *> receivers;
-
-  Mutex mutex;
-};
-
-// Global MessageHandler;
-extern MessageHandler msghandler;
-
-#endif/*__DRUMGIZMO_MESSAGEHANDLER_H__*/
diff --git a/src/messagereceiver.cc b/src/messagereceiver.cc
deleted file mode 100644
index 590c98a..0000000
--- a/src/messagereceiver.cc
+++ /dev/null
@@ -1,78 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/***************************************************************************
- *            messagereceiver.cc
- *
- *  Sun Jun 16 12:09:06 CEST 2013
- *  Copyright 2013 Bent Bisballe Nyeng
- *  deva@aasimon.org
- ****************************************************************************/
-
-/*
- *  This file is part of DrumGizmo.
- *
- *  DrumGizmo is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU Lesser General Public License as published by
- *  the Free Software Foundation; either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  DrumGizmo 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 Lesser General Public License for more details.
- *
- *  You should have received a copy of the GNU Lesser General Public License
- *  along with DrumGizmo; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
- */
-#include "messagereceiver.h"
-
-#include <hugin.hpp>
-
-MessageReceiver::MessageReceiver(message_receiver_id_t id)
-{
-  msghandler.addReceiver(id, this);
-}
-
-MessageReceiver::~MessageReceiver()
-{
-  msghandler.removeReceiver(this);
-}
-
-void MessageReceiver::sendMessage(Message *msg)
-{
-  MutexAutolock l(message_mutex);
-
-  message_queue.push_back(msg);
-}
-
-Message *MessageReceiver::receiveMessage()
-{
-  Message *msg = NULL;
-  if(message_queue.size()) {
-    msg = message_queue.front();
-    message_queue.pop_front();
-  }
-  return msg;
-}
-
-Message *MessageReceiver::peekMessage()
-{
-  Message *msg = NULL;
-  if(message_queue.size()) {
-    msg = message_queue.front();
-  }
-  return msg;
-}
-
-void MessageReceiver::handleMessages(size_t max)
-{
-  MutexAutolock l(message_mutex);
-  bool process_all = false;
-  if(max == 0) process_all = true;
-
-  while((process_all || max--) && peekMessage()) {
-    Message *msg = receiveMessage();
-    handleMessage(msg);
-    delete msg;
-  }
-}
diff --git a/src/messagereceiver.h b/src/messagereceiver.h
deleted file mode 100644
index c1a8e60..0000000
--- a/src/messagereceiver.h
+++ /dev/null
@@ -1,75 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/***************************************************************************
- *            messagereceiver.h
- *
- *  Sun Jun 16 12:09:06 CEST 2013
- *  Copyright 2013 Bent Bisballe Nyeng
- *  deva@aasimon.org
- ****************************************************************************/
-
-/*
- *  This file is part of DrumGizmo.
- *
- *  DrumGizmo is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU Lesser General Public License as published by
- *  the Free Software Foundation; either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  DrumGizmo 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 Lesser General Public License for more details.
- *
- *  You should have received a copy of the GNU Lesser General Public License
- *  along with DrumGizmo; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
- */
-#ifndef __DRUMGIZMO_MESSAGERECEIVER_H__
-#define __DRUMGIZMO_MESSAGERECEIVER_H__
-
-#include <list>
-
-#include "mutex.h"
-#include "message.h"
-#include "messagehandler.h"
-
-class MessageReceiver {
-  friend class MessageHandler;
-public:
-  MessageReceiver(message_receiver_id_t id);
-  ~MessageReceiver();
-
-  /**
-   * Receive message from the message queue.
-   */
-  Message *receiveMessage();
-
-  /**
-   * Receive message from the message queue without removing it.
-   */
-  Message *peekMessage();
-
-  /**
-   * Add a message to the message queue.
-   */
-  void sendMessage(Message *msg);
-
-  /**
-   * Handle messages from the event queue.
-   * @param max_number_of_events the maximum number of events to be handled in
-   * this call. 0 means all.
-   */
-  void handleMessages(size_t max_number_of_events = 0);
-
-  /**
-   * Handler to be implemented in child classes.
-   * Handles a single event.
-   */
-  virtual void handleMessage(Message *msg) = 0;
-
-private:
-  Mutex message_mutex;
-  std::list<Message *> message_queue;
-};
-
-#endif/*__DRUMGIZMO_MESSAGERECEIVER_H__*/
diff --git a/src/midimapparser.cc b/src/midimapparser.cc
index ec4c10d..cc97280 100644
--- a/src/midimapparser.cc
+++ b/src/midimapparser.cc
@@ -30,7 +30,8 @@ void MidiMapParser::startTag(const std::string& name, const attr_t& attr)
 {
 	if(name == "map")
 	{
-		if(attr.find("note") != attr.end() && attr.find("instr") != attr.end())
+		if((attr.find("note") != attr.end()) &&
+		   (attr.find("instr") != attr.end()))
 		{
 			midimap[std::stoi(attr.at("note"))] = attr.at("instr");
 		}
diff --git a/src/midimapparser.h b/src/midimapparser.h
index 740cb60..8ec76c0 100644
--- a/src/midimapparser.h
+++ b/src/midimapparser.h
@@ -26,8 +26,6 @@
  */
 #pragma once
 
-#include <stdio.h>
-
 #include "saxparser.h"
 #include "midimapper.h"
 
diff --git a/src/notifier.h b/src/notifier.h
new file mode 100644
index 0000000..ff59741
--- /dev/null
+++ b/src/notifier.h
@@ -0,0 +1,163 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/***************************************************************************
+ *            notifier.h
+ *
+ *  Thu Sep  3 15:48:39 CEST 2015
+ *  Copyright 2015 Bent Bisballe Nyeng
+ *  deva@aasimon.org
+ ****************************************************************************/
+
+/*
+ *  This file is part of DrumGizmo.
+ *
+ *  DrumGizmo is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  DrumGizmo 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 Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with DrumGizmo; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+ */
+#pragma once
+
+#include <functional>
+#include <vector>
+#include <map>
+#include <set>
+#include <memory>
+
+namespace aux
+{
+	template<int>
+	struct placeholder
+	{
+	};
+}
+
+namespace std
+{
+	template<int N>
+	struct is_placeholder<aux::placeholder<N>>
+		: integral_constant<int, N+1>
+	{
+	};
+}
+
+namespace aux
+{
+	// std::integer_sequence introduced in C++14 so remove this once we start requiring that.
+
+	template<int... Ns>
+	struct int_sequence
+	{
+	};
+
+	template<int N, int... Ns>
+	struct gen_int_sequence
+		: gen_int_sequence<N-1, N-1, Ns...>
+	{
+	};
+
+	template<int... Ns>
+	struct gen_int_sequence<0, Ns...>
+		: int_sequence<Ns...>
+	{
+	};
+};
+
+
+//namespace GUI {
+
+class Listener;
+class NotifierBase {
+public:
+	virtual void disconnect(Listener* object) {}
+};
+
+class Listener {
+public:
+	virtual ~Listener()
+	{
+		for(auto signal : signals)
+		{
+			signal->disconnect(this);
+		}
+	}
+
+	void registerNotifier(NotifierBase* signal)
+	{
+		signals.insert(signal);
+	}
+
+	void unregisterNotifier(NotifierBase* signal)
+	{
+		signals.erase(signal);
+	}
+
+private:
+	std::set<NotifierBase*> signals;
+};
+
+template<typename... Args>
+class Notifier : public NotifierBase {
+public:
+	Notifier() {}
+
+	//! \brief When dtor is called it will automatically disconnect all its listeners.
+	~Notifier()
+	{
+		for(auto& slot : slots)
+		{
+			slot.first->unregisterNotifier(this);
+		}
+	}
+
+	using callback_type = std::function<void(Args...)>;
+
+	//! \brief Connect object to this Notifier.
+	template<typename O, typename F>
+	void connect(O* p, const F& fn)
+	{
+		slots[p] = std::move(construct_mem_fn(fn, p, aux::gen_int_sequence<sizeof...(Args)>{}));
+		if(p && dynamic_cast<Listener*>(p))
+		{
+			dynamic_cast<Listener*>(p)->registerNotifier(this);
+		}
+	}
+
+	//! \brief Disconnect object from this Notifier.
+	void disconnect(Listener* object)
+	{
+		slots.erase(object);
+	}
+
+	//! \brief Activate this notifier by pretending it is a function.
+	//! Example: Notifier<int> foo; foo(42);
+	void operator()(Args... args)
+	{
+		for(auto& slot : slots)
+		{
+			slot.second(args...);
+		}
+	}
+
+private:
+	std::map<Listener*, callback_type> slots;
+
+	template<typename F, typename O, int... Ns>
+	callback_type construct_mem_fn(const F& fn, O* p, aux::int_sequence<Ns...>) const
+	{
+		return std::bind(fn, p, aux::placeholder<Ns>{}...);
+	}
+
+};
+
+//} // GUI::
+
+#define CONNECT(SRC, SIG, TAR, SLO) (SRC)->SIG.connect(TAR, SLO)
diff --git a/src/path.cc b/src/path.cc
index 43c64f0..c2e7910 100644
--- a/src/path.cc
+++ b/src/path.cc
@@ -35,17 +35,19 @@
 
 std::string getPath(const std::string& file)
 {
-	std::string p;
-#ifndef __MINGW32__
-	char *b = strdup(file.c_str());
-	p = dirname(b);
-	free(b);
-#else
+	std::string path;
+
+#ifdef __MINGW32__
 	char drive[_MAX_DRIVE];
 	char dir[_MAX_DIR];
 	_splitpath(file.c_str(), drive, dir, NULL, NULL);
-	p = std::string(drive) + dir;
+	path = std::string(drive) + dir;
+#else
+	// POSIX
+	char* buffer = strdup(file.c_str());
+	path = dirname(buffer);
+	free(buffer);
 #endif
 
-	return p;
+	return path;
 }
diff --git a/src/path.h b/src/path.h
index 7189cea..50ff842 100644
--- a/src/path.h
+++ b/src/path.h
@@ -28,4 +28,5 @@
 
 #include <string>
 
+//! \returns path component of full filename with path.
 std::string getPath(const std::string& file);
diff --git a/src/sample.cc b/src/sample.cc
index 66fe3c5..ced8a47 100644
--- a/src/sample.cc
+++ b/src/sample.cc
@@ -65,24 +65,3 @@ AudioFile* Sample::getAudioFile(Channel* c)
 
 	return nullptr;
 }
-
-#ifdef TEST_SAMPLE
-// deps: channel.cc audiofile.cc
-// cflags: $(SNDFILE_CFLAGS)
-// libs: $(SNDFILE_LIBS)
-#include "test.h"
-
-TEST_BEGIN;
-
-Sample s;
-InstrumentChannel c;
-InstrumentChannel c2;
-AudioFile a("test");
-
-s.addAudioFile(&c, &a);
-TEST_EQUAL(s.getAudioFile(&c), &a, "?");
-TEST_EQUAL(s.getAudioFile(&c2), nullptr, "?");
-
-TEST_END;
-
-#endif /*TEST_SAMPLE*/
diff --git a/src/sample.h b/src/sample.h
index 5b4f3b5..f00db13 100644
--- a/src/sample.h
+++ b/src/sample.h
@@ -32,34 +32,22 @@
 #include "channel.h"
 #include "audiofile.h"
 
-typedef std::map<Channel*, AudioFile*> AudioFiles;
+using AudioFiles = std::map<Channel*, AudioFile*>;
 
-class InstrumentParser;
-class Sample
-{
+class Sample {
 	friend class InstrumentParser;
 	friend class PowerList;
-
 public:
 	Sample(const std::string& name, float power);
 	~Sample();
 
-	AudioFile* getAudioFile(InstrumentChannel* c);
+	AudioFile* getAudioFile(InstrumentChannel *instrument_channel);
 
 private:
-	void addAudioFile(InstrumentChannel* c, AudioFile* a);
+	void addAudioFile(InstrumentChannel* instrument_channel,
+	                  AudioFile* audio_file);
 
 	std::string name;
 	float power;
 	AudioFiles audiofiles;
 };
-
-/*
- *   <sample name="kick-r-1">
- *    <audiofile channel="Alesis-3" file="samples/1-kick-r-Alesis-3.wav"/>
- *    <audiofile channel="Amb L-3" file="samples/1-kick-r-Amb L-3.wav"/>
- *    <audiofile channel="Amb R-3" file="samples/1-kick-r-Amb R-3.wav"/>
- *    <audiofile channel="Kick L-3" file="samples/1-kick-r-Kick L-3.wav"/>
- *    <audiofile channel="Kick R-3" file="samples/1-kick-r-Kick R-3.wav"/>
- *   </sample>
- */
diff --git a/src/saxparser.cc b/src/saxparser.cc
index e32143d..280e608 100644
--- a/src/saxparser.cc
+++ b/src/saxparser.cc
@@ -26,29 +26,30 @@
  */
 #include "saxparser.h"
 
-#include <string.h>
-#include <hugin.hpp>
 #include <sstream>
 #include <iostream>
 
+#include <hugin.hpp>
+
 SAXParser::SAXParser()
 {
-	p = XML_ParserCreate(nullptr);
-	if(!p) {
+	parser = XML_ParserCreate(nullptr);
+	if(!parser)
+	{
 		ERR(sax, "Couldn't allocate memory for parser\n");
 		// throw Exception(...); TODO
 		return;
 	}
 
-	XML_SetUserData(p, this);
-	XML_UseParserAsHandlerArg(p);
-	XML_SetElementHandler(p, start_hndl, end_hndl);
-	XML_SetCharacterDataHandler(p, character_hndl);
+	XML_SetUserData(parser, this);
+	XML_UseParserAsHandlerArg(parser);
+	XML_SetElementHandler(parser, SAXParser::startHandler, SAXParser::endHandler);
+	XML_SetCharacterDataHandler(parser, SAXParser::characterHandler);
 }
 
 SAXParser::~SAXParser()
 {
-	XML_ParserFree(p);
+	XML_ParserFree(parser);
 }
 
 int SAXParser::parseFile(const std::string& filename)
@@ -60,7 +61,8 @@ int SAXParser::parseFile(const std::string& filename)
 
 	std::ifstream file(filename, std::ifstream::in);
 
-	if(!file.is_open()) {
+	if(!file.is_open())
+	{
 		return 1;
 	}
 
@@ -68,59 +70,63 @@ int SAXParser::parseFile(const std::string& filename)
 	ss << file.rdbuf();
 	std::string str = ss.str();
 
-	parseString(str, filename);
-
-	return 0;
+	return parseString(str, filename);
 }
 
-int SAXParser::parseString(const std::string& str, const std::string& xml_source_name)
+int SAXParser::parseString(const std::string& str,
+                           const std::string& xml_source_name)
 {
 	DEBUG(sax, "parse(buffer %d bytes)\n", (int)str.length());
 
-	if(!XML_Parse(p, str.c_str(), str.length(), true)) {
-		parseError(str, XML_ErrorString(XML_GetErrorCode(p)),
-		           xml_source_name, (int)XML_GetCurrentLineNumber(p));
+	if(!XML_Parse(parser, str.c_str(), str.length(), true))
+	{
+		parseError(str, XML_ErrorString(XML_GetErrorCode(parser)),
+		           xml_source_name, (int)XML_GetCurrentLineNumber(parser));
 		return 1;
 	}
 
 	return 0;
 }
 
-void SAXParser::parseError(const std::string& buf, const std::string& error, const std::string& xml_source_name, std::size_t lineno)
+void SAXParser::parseError(const std::string& buf, const std::string& error,
+                           const std::string& xml_source_name,
+                           std::size_t lineno)
 {
-	std::cerr << "SAXParser error trying to parse from source: " << xml_source_name << "\n";
+	std::cerr << "SAXParser error trying to parse from source: " <<
+		xml_source_name << "\n";
 	std::cerr << "At line " << lineno << ": " << error << "\n";
 	std::cerr << "Buffer " << buf.size() << " bytes: \n[\n";
 	std::cerr << buf;
 	std::cerr << "\n]" << std::endl;
 }
 
-void SAXParser::character_hndl(void* p, const XML_Char* s, int len)
+void SAXParser::characterHandler(void* parser, const XML_Char* cData, int len)
 {
-	SAXParser* parser = (SAXParser*)XML_GetUserData(p);
-	std::string chars(s, len);
-	parser->characterData(chars);
+	SAXParser* sax_parser = (SAXParser*)XML_GetUserData(parser);
+	std::string chars(cData, len);
+	sax_parser->characterData(chars);
 }
 
-void SAXParser::start_hndl(void* p, const char* el, const char** attr)
+void SAXParser::startHandler(void* parser, const char* el, const char** attr)
 {
-	SAXParser* parser = (SAXParser*)XML_GetUserData(p);
+	SAXParser* sax_parser = (SAXParser*)XML_GetUserData(parser);
 
 	// Convert to comfy C++ values...
 	attr_t attributes;
 
-	while(*attr) {
+	while(*attr)
+	{
 		std::string at_name = *attr++;
 		std::string at_value = *attr++;
 
 		attributes.emplace(at_name, at_value);
 	}
 
-	parser->startTag(std::string(el), attributes);
+	sax_parser->startTag(std::string(el), attributes);
 }
 
-void SAXParser::end_hndl(void* p, const char* el)
+void SAXParser::endHandler(void* parser, const char* el)
 {
-	SAXParser* parser = (SAXParser*)XML_GetUserData(p);
-	parser->endTag(std::string(el));
+	SAXParser* sax_parser = (SAXParser*)XML_GetUserData(parser);
+	sax_parser->endTag(std::string(el));
 }
diff --git a/src/saxparser.h b/src/saxparser.h
index 92197d1..4b1a273 100644
--- a/src/saxparser.h
+++ b/src/saxparser.h
@@ -31,7 +31,8 @@
 #include <expat.h>
 #include <fstream>
 
-class SAXParser {
+class SAXParser
+{
 public:
 	SAXParser();
 	virtual ~SAXParser();
@@ -40,7 +41,8 @@ public:
 	virtual int parseFile(const std::string& filename);
 
 	//! Parses all the data in the buffer.
-	virtual int parseString(const std::string& str, const std::string& xml_source_name = "");
+	virtual int parseString(const std::string& str,
+	                        const std::string& xml_source_name = "");
 
 protected:
 	using attr_t = std::unordered_map<std::string, std::string>;
@@ -48,13 +50,16 @@ protected:
 	virtual void characterData(const std::string& data) {}
 	virtual void startTag(const std::string& name, const attr_t& attr) {}
 	virtual void endTag(const std::string& name) {}
-	virtual void parseError(const std::string& buf, const std::string& error, const std::string& xml_source_name, std::size_t lineno);
+	virtual void parseError(const std::string& buf,
+	                        const std::string& error,
+	                        const std::string& xml_source_name,
+	                        std::size_t lineno);
 
 private:
-	XML_Parser p;
+	XML_Parser parser;
 	std::string filename;
 
-	static void character_hndl(void* p, const XML_Char* s, int len);
-	static void start_hndl(void* p, const char* el, const char** attr);
-	static void end_hndl(void* p, const char* el);
+	static void characterHandler(void* parser, const XML_Char* cData, int len);
+	static void startHandler(void* parser, const char* el, const char** attr);
+	static void endHandler(void* parser, const char* el);
 };
diff --git a/src/semaphore.cc b/src/semaphore.cc
index cd29bbf..6172251 100644
--- a/src/semaphore.cc
+++ b/src/semaphore.cc
@@ -27,87 +27,101 @@
 #include "semaphore.h"
 
 #include <hugin.hpp>
-
 #include <limits>
+#include <assert.h>
 
 #ifdef WIN32
 #include <windows.h>
 #else
-// Make sure we don't include /this/ file...
+// Make sure we don't include /this/ files header...
 #include <../include/semaphore.h>
+#include <errno.h>
+#include <stdio.h>
 #endif
 
 struct semaphore_private_t {
 #ifdef WIN32
-  HANDLE semaphore; 
+	HANDLE semaphore;
 #else
-  sem_t semaphore;
+	sem_t semaphore;
 #endif
 };
 
-Semaphore::Semaphore(const char *name)
+Semaphore::Semaphore(std::size_t initial_count)
 {
-  this->name = name;
-  //  DEBUG(semaphore, "Create [%s]\n", name);
-
-  prv = new struct semaphore_private_t();
+	prv = new struct semaphore_private_t();
 
 #ifdef WIN32
-  prv->semaphore = CreateSemaphore(NULL,  // default security attributes
-                                   0, // initial count
-                                   std::numeric_limits<LONG>::max(),
-                                   NULL); // unnamed semaphore
+	prv->semaphore = CreateSemaphore(nullptr,  // default security attributes
+	                                 initial_count,
+	                                 std::numeric_limits<LONG>::max(),
+	                                 nullptr); // unnamed semaphore
 #else
-  sem_init(&prv->semaphore, 0, 0);
+	const int pshared = 0;
+	sem_init(&prv->semaphore, pshared, initial_count);
 #endif
 }
 
 Semaphore::~Semaphore()
 {
-  //  DEBUG(semaphore, "Delete [%s]\n", name);
-
 #ifdef WIN32
-  CloseHandle(prv->semaphore);
+	CloseHandle(prv->semaphore);
 #else
-  sem_destroy(&prv->semaphore);
+	sem_destroy(&prv->semaphore);
 #endif
 
-  delete prv;
+	delete prv;
 }
 
 void Semaphore::post()
 {
-  //  DEBUG(semaphore, "Post [%s]\n", name);
+#ifdef WIN32
+	ReleaseSemaphore(prv->semaphore, 1, NULL);
+#else
+	sem_post(&prv->semaphore);
+#endif
+}
 
+bool Semaphore::wait(const std::chrono::milliseconds& timeout)
+{
 #ifdef WIN32
-  ReleaseSemaphore(prv->semaphore, 1, NULL);
+	DWORD ret = WaitForSingleObject(prv->semaphore, timeout.count());
+	if(ret == WAIT_TIMEOUT)
+	{
+		return false;
+	}
+
+	assert(ret == WAIT_OBJECT_0);
 #else
-  sem_post(&prv->semaphore);
+	struct timespec t = {
+		// Whole seconds:
+		(time_t)(timeout.count() / 1000),
+
+		// Remainder as nanoseconds:
+		(long)((timeout.count() - ((timeout.count() / 1000) * 1000)) * 1000000)
+	};
+
+	int ret = sem_timedwait(&prv->semaphore, &t);
+	if(ret < 0)
+	{
+		if(errno == ETIMEDOUT)
+		{
+			return false;
+		}
+
+		perror("sem_timedwait()");
+		assert(false);
+	}
 #endif
+
+	return true;
 }
 
 void Semaphore::wait()
 {
-  //  DEBUG(semaphore, "Wait [%s]\n", name);
-
 #ifdef WIN32
-  WaitForSingleObject(prv->semaphore, INFINITE);
+	WaitForSingleObject(prv->semaphore, INFINITE);
 #else
-  sem_wait(&prv->semaphore);
+	sem_wait(&prv->semaphore);
 #endif
 }
-
-#ifdef TEST_SEMAPHORE
-//deps:
-//cflags: -I.. $(PTHREAD_CFLAGS)
-//libs: $(PTHREAD_LIBS)
-#include <test.h>
-
-TEST_BEGIN;
-
-// TODO: Put some testcode here (see test.h for usable macros).
-TEST_TRUE(false, "No tests yet!");
-
-TEST_END;
-
-#endif/*TEST_SEMAPHORE*/
diff --git a/src/semaphore.h b/src/semaphore.h
index 4464898..d5995cb 100644
--- a/src/semaphore.h
+++ b/src/semaphore.h
@@ -24,22 +24,26 @@
  *  along with DrumGizmo; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
  */
-#ifndef __PRACRO_SEMAPHORE_H__
-#define __PRACRO_SEMAPHORE_H__
+#pragma once
+
+#include <chrono>
 
 struct semaphore_private_t;
 
-class Semaphore {
+class Semaphore
+{
 public:
-  Semaphore(const char *name = "");
-  ~Semaphore();
+	Semaphore(std::size_t initial_count = 0);
+	~Semaphore();
+
+	void post();
 
-  void post();
-  void wait();
+	//! Lock semaphore with timeout.
+	//! \returns true if the semaphore was locked, false on timeout.
+	bool wait(const std::chrono::milliseconds& timeout);
+
+	void wait();
 
 private:
 	struct semaphore_private_t *prv{nullptr};
-	const char *name{nullptr};
 };
-
-#endif/*__PRACRO_SEMAPHORE_H__*/
diff --git a/src/settings.h b/src/settings.h
index 74c432d..6b4e882 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -27,52 +27,54 @@
 #pragma once
 
 #include <atomic>
+#include <string>
 #include <cassert>
 
-template <typename T> class SettingRef
-{
-public:
-	SettingRef(std::atomic<T>& value)
-		: value{value}
-		, cache{}
-	{
-		// string isn't lock free either
-		assert((std::is_same<T, std::string>::value || value.is_lock_free()));
-	}
-
-	bool hasChanged()
-	{
-		T tmp = cache;
-		cache.exchange(value);
-		return tmp == cache;
-	}
+#include "atomic.h"
+#include "notifier.h"
 
-	T getValue() const
-	{
-		return cache;
-	}
-
-private:
-	std::atomic<T>& value;
-	std::atomic<T> cache;
+enum class LoadStatus : unsigned int
+{
+	Idle,
+	Loading,
+	Done,
+	Error
 };
 
+//! Engine settings
 struct Settings
 {
-	std::atomic<bool> enable_velocity_modifier;
-	std::atomic<float> velocity_modifier_falloff;
-	std::atomic<float> velocity_modifier_weight;
+	Atomic<std::string> drumkit_file;
+	Atomic<LoadStatus> drumkit_load_status{LoadStatus::Idle};
+
+	Atomic<std::string> midimap_file;
+	Atomic<LoadStatus> midimap_load_status{LoadStatus::Idle};
+
+	Atomic<bool> enable_velocity_modifier{true};
+	Atomic<float> velocity_modifier_falloff{0.5f};
+	Atomic<float> velocity_modifier_weight{0.25f};
 
-	std::atomic<bool> enable_velocity_randomiser;
-	std::atomic<float> velocity_randomiser_weight;
+	Atomic<bool> enable_velocity_randomiser{false};
+	Atomic<float> velocity_randomiser_weight{0.1f};
 
-	std::atomic<int> samplerate;
+	Atomic<double> samplerate{44100.0};
 
-	std::atomic<bool> enable_resampling;
+	Atomic<bool> enable_resampling{true};
+
+	Atomic<std::size_t> number_of_files;
+	Atomic<std::size_t> number_of_files_loaded;
+	Atomic<std::string> current_file;
 };
 
+//! Settings getter class.
 struct SettingsGetter
 {
+	SettingRef<std::string> drumkit_file;
+	SettingRef<LoadStatus> drumkit_load_status;
+
+	SettingRef<std::string> midimap_file;
+	SettingRef<LoadStatus> midimap_load_status;
+
 	SettingRef<bool> enable_velocity_modifier;
 	SettingRef<float> velocity_modifier_falloff;
 	SettingRef<float> velocity_modifier_weight;
@@ -80,48 +82,125 @@ struct SettingsGetter
 	SettingRef<bool> enable_velocity_randomiser;
 	SettingRef<float> velocity_randomiser_weight;
 
-	SettingRef<int> samplerate;
+	SettingRef<double> samplerate;
 
 	SettingRef<bool> enable_resampling;
 
+	SettingRef<std::size_t> number_of_files;
+	SettingRef<std::size_t> number_of_files_loaded;
+	SettingRef<std::string> current_file;
+
 	SettingsGetter(Settings& settings)
-		: enable_velocity_modifier{settings.enable_velocity_modifier}
+		: drumkit_file(settings.drumkit_file)
+		, drumkit_load_status(settings.drumkit_load_status)
+		, midimap_file(settings.midimap_file)
+		, midimap_load_status(settings.midimap_load_status)
+		, enable_velocity_modifier{settings.enable_velocity_modifier}
 		, velocity_modifier_falloff{settings.velocity_modifier_falloff}
 		, velocity_modifier_weight{settings.velocity_modifier_weight}
 		, enable_velocity_randomiser{settings.enable_velocity_randomiser}
 		, velocity_randomiser_weight{settings.velocity_randomiser_weight}
 		, samplerate{settings.samplerate}
 		, enable_resampling{settings.enable_resampling}
+		, number_of_files{settings.number_of_files}
+		, number_of_files_loaded{settings.number_of_files_loaded}
+		, current_file{settings.current_file}
 	{
 	}
 };
 
+//! Settings change notifier class.
+class SettingsNotifier
+{
+public:
+	Notifier<std::string> drumkit_file;
+	Notifier<LoadStatus> drumkit_load_status;
+
+	Notifier<std::string> midimap_file;
+	Notifier<LoadStatus> midimap_load_status;
+
+	Notifier<bool> enable_velocity_modifier;
+	Notifier<float> velocity_modifier_falloff;
+	Notifier<float> velocity_modifier_weight;
+
+	Notifier<bool> enable_velocity_randomiser;
+	Notifier<float> velocity_randomiser_weight;
+
+	Notifier<double> samplerate;
+
+	Notifier<bool> enable_resampling;
+
+	Notifier<std::size_t> number_of_files;
+	Notifier<std::size_t> number_of_files_loaded;
+	Notifier<std::string> current_file;
+
+	void evaluate()
+	{
+#define EVAL(x) if(settings.x.hasChanged()) { x(settings.x.getValue()); }
+
+		EVAL(drumkit_file);
+		EVAL(drumkit_load_status);
+
+		EVAL(midimap_file);
+		EVAL(midimap_load_status);
+
+		EVAL(enable_velocity_modifier);
+		EVAL(velocity_modifier_falloff);
+		EVAL(velocity_modifier_weight);
+
+		EVAL(enable_velocity_randomiser);
+		EVAL(velocity_randomiser_weight);
+
+		EVAL(samplerate);
+
+		EVAL(enable_resampling);
+
+		EVAL(number_of_files);
+		EVAL(number_of_files_loaded);
+		EVAL(current_file);
+	}
+
+	SettingsNotifier(Settings& settings)
+		: settings(settings)
+	{
+	}
+
+private:
+	SettingsGetter settings;
+};
+
 // lovely reminder: NO, GLOCKE. NOOOO!!
 /*
 enum class IntParams {
-    Foo = 0
+	Foo = 0
 };
 
-struct Settings {
-    std::array<std::atomic<int>, 5> ints;
+struct Settings
+{
+	std::array<std::atomic<int>, 5> ints;
 
-    Settings()
-        : ints{} {
-        //get(IntParams::Foo).store(3);
-    }
+	Settings()
+		: ints{}
+	{
+		//get(IntParams::Foo).store(3);
+	}
 
-    std::atomic<int>& get(IntParams param) {
-        return ints[(size_t)param];
-    }
+	std::atomic<int>& get(IntParams param)
+	{
+		return ints[(size_t)param];
+	}
 };
 
-struct SettingsGetter {
-    std::vector<SettingRef<int>> ints;
+struct SettingsGetter
+{
+	std::vector<SettingRef<int>> ints;
 
-    SettingsGetter(Settings& parent) {
-        for (auto& atomic: parent.ints) {
-            ints.emplace_back(atomic);
-        }
-    }
+	SettingsGetter(Settings& parent)
+	{
+		for(auto& atomic: parent.ints)
+		{
+			ints.emplace_back(atomic);
+		}
+	}
 };
 */
diff --git a/src/syncedsettings.h b/src/syncedsettings.h
new file mode 100644
index 0000000..0fe5efd
--- /dev/null
+++ b/src/syncedsettings.h
@@ -0,0 +1,106 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/***************************************************************************
+ *            syncedsettings.h
+ *
+ *  Thu Mar 31 09:23:27 CEST 2016
+ *  Copyright 2016 Christian Glöckner
+ *  cgloeckner@freenet.de
+ ****************************************************************************/
+
+/*
+ *  This file is part of DrumGizmo.
+ *
+ *  DrumGizmo is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  DrumGizmo 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 Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with DrumGizmo; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+ */
+#pragma once
+
+#include <mutex>
+
+template <typename T> class Group;
+
+template <typename T> class Accessor
+{
+private:
+	std::lock_guard<std::mutex> lock;
+
+public:
+	Accessor(Group<T>& parent)
+		: lock{parent.mutex}
+		, data(parent.data)
+	{
+	}
+
+	T& data;
+};
+
+template <typename T> class Group
+{
+private:
+	friend class Accessor<T>;
+
+	mutable std::mutex mutex;
+	T data;
+
+public:
+	Group()
+		: mutex{}
+		, data{}
+	{
+	}
+
+	Group(Group<T> const& other)
+		: mutex{}
+		, data{}
+	{
+		std::lock_guard<std::mutex> lock{other.mutex};
+		data = other.data;
+	}
+
+	Group(Group<T>&& other)
+		: mutex{}
+		, data{}
+	{
+		std::lock_guard<std::mutex> lock{other.mutex};
+		std::swap(data, other.data);
+	}
+
+	Group<T>& operator=(const Group<T>& other)
+	{
+		if (*this != &other)
+		{
+			std::lock_guard<std::mutex> lock{mutex};
+			std::lock_guard<std::mutex> lock2{other.mutex};
+			data = other.data;
+		}
+		return *this;
+	}
+	
+	Group<T>& operator=(Group<T>&& other)
+	{
+		if (*this != &other)
+		{
+			std::lock_guard<std::mutex> lock{mutex};
+			std::lock_guard<std::mutex> lock2{other.mutex};
+			std::swap(data, other.data);
+		}
+		return *this;
+	}
+
+	operator T() const
+	{
+		std::lock_guard<std::mutex> lock{mutex};
+		return data;
+	}
+};