Refactoring to finally get rid of MessageHandler/Receiver in favor of the new Settings mechanism.

15 files changed, 373 insertions, 610 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 9dd6c29..4d167af 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -23,13 +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 \
@@ -62,8 +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 e707fe2..6fddded 100644
--- a/src/Makefile.am.drumgizmo
+++ b/src/Makefile.am.drumgizmo
@@ -20,8 +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
index e0b80b1..95a5e9d 100644
--- a/src/atomic.h
+++ b/src/atomic.h
@@ -116,7 +116,67 @@ public:
 		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/drumgizmo.cc b/src/drumgizmo.cc
index f769f4e..aa6be23 100644
--- a/src/drumgizmo.cc
+++ b/src/drumgizmo.cc
@@ -38,6 +38,7 @@
 #include <hugin.hpp>
 
 #include <config.h>
+#include <memory>
 
 #include "drumkitparser.h"
 #include "audioinputenginemidi.h"
@@ -47,8 +48,7 @@
 
 DrumGizmo::DrumGizmo(Settings& settings,
                      AudioOutputEngine *o, AudioInputEngine *i)
-	: MessageReceiver(MSGRCV_ENGINE)
-	, loader(settings)
+	: loader(settings)
 	, oe(o)
 	, ie(i)
 	, framesize(0)
@@ -69,9 +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());
@@ -82,20 +85,24 @@ bool DrumGizmo::loadkit(std::string file)
 	// Delete all Channels, Instruments, Samples and AudioFiles.
 	kit.clear();
 
+	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);
 
@@ -126,79 +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 = settings.enable_velocity_modifier.load();
-			msg->velocity_modifier_falloff = settings.velocity_modifier_falloff.load();
-			msg->velocity_modifier_weight = settings.velocity_modifier_weight.load();
-			msg->enable_velocity_randomiser = settings.enable_velocity_randomiser.load();
-			msg->velocity_randomiser_weight = settings.velocity_randomiser_weight.load();
-			msghandler.sendMessage(MSGRCV_UI, msg);
-		}
-		break;
-	case Message::ChangeSettingMessage:
-		{
-			ChangeSettingMessage *ch = (ChangeSettingMessage*)msg;
-			switch(ch->name) {
-			case ChangeSettingMessage::enable_velocity_modifier:
-				settings.enable_velocity_modifier.store(ch->value);
-				break;
-			case ChangeSettingMessage::velocity_modifier_weight:
-				settings.velocity_modifier_weight.store(ch->value);
-				break;
-			case ChangeSettingMessage::velocity_modifier_falloff:
-				settings.velocity_modifier_falloff.store(ch->value);
-				break;
-			}
-		}
-		break;
-	default:
-		break;
-	}
-}
-
 void DrumGizmo::setFrameSize(size_t framesize)
 {
 	// If we are resampling override the frame size.
@@ -260,8 +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);
@@ -712,8 +669,8 @@ 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") != "")
@@ -747,27 +704,15 @@ bool DrumGizmo::setConfigString(std::string cfg)
 	}
 
 	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 63348da..7af5dbb 100644
--- a/src/drumgizmo.h
+++ b/src/drumgizmo.h
@@ -31,25 +31,15 @@
 
 #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
@@ -57,7 +47,6 @@
 #define RESAMPLER_INPUT_BUFFER 64
 
 class DrumGizmo
-	: public MessageReceiver
 {
 public:
 	DrumGizmo(Settings& settings,
@@ -77,8 +66,6 @@ public:
 	std::string configString();
 	bool setConfigString(std::string cfg);
 
-	void handleMessage(Message *msg);
-
 	int samplerate();
 	void setSamplerate(int samplerate);
 
@@ -112,4 +99,5 @@ protected:
 
 	std::vector<event_t> events;
 	Settings& settings;
+	SettingsGetter getter{settings};
 };
diff --git a/src/drumkitloader.cc b/src/drumkitloader.cc
index 3cb4b68..f9e45db 100644
--- a/src/drumkitloader.cc
+++ b/src/drumkitloader.cc
@@ -184,18 +184,14 @@ void DrumKitLoader::thread_main()
 			audiofile->load(preload_size);
 		}
 
-		loaded++;
+		++loaded;
 
-		if(loaded % fraction == 0 || loaded == total_num_audiofiles)
+		settings.number_of_files.store(total_num_audiofiles);
+		settings.number_of_files_loaded.store(loaded);
+
+		if(total_num_audiofiles == 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.number_of_files.store(total_num_audiofiles);
-			settings.number_of_files_loaded.store(loaded);
-			//settings.current_file.store(filename);
+			settings.drumkit_load_status.store(LoadStatus::Done);
 		}
 	}
 
diff --git a/src/drumkitparser.cc b/src/drumkitparser.cc
index 221e921..048a05b 100644
--- a/src/drumkitparser.cc
+++ b/src/drumkitparser.cc
@@ -34,7 +34,7 @@
 #include "path.h"
 #include "drumgizmo.h"
 
-DrumKitParser::DrumKitParser(Settings& setting, DrumKit& k)
+DrumKitParser::DrumKitParser(Settings& settings, DrumKit& k)
 	: kit(k)
 	, refs(REFSFILE)
 	, settings(settings)
diff --git a/src/instrument.cc b/src/instrument.cc
index f187de0..cc052e9 100644
--- a/src/instrument.cc
+++ b/src/instrument.cc
@@ -42,7 +42,7 @@ Instrument::Instrument(Settings& settings)
 
 Instrument::~Instrument()
 {
-	magic = NULL;
+	magic = nullptr;
 
 	DEBUG(instrument, "delete %p\n", this);
 	std::vector<AudioFile*>::iterator i = audiofiles.begin();
@@ -60,8 +60,6 @@ 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();
@@ -70,6 +68,8 @@ Sample* Instrument::sample(level_t level, size_t pos)
 	auto enable_velocity_modifier = settings.enable_velocity_modifier.load();
 	auto velocity_modifier_weight = settings.velocity_modifier_weight.load();
 
+	Sample *sample = nullptr;
+
 	if(enable_velocity_modifier == false)
 	{
 		mod = 1.0;
@@ -78,14 +78,13 @@ Sample* Instrument::sample(level_t level, size_t pos)
 
 	if(enable_velocity_randomiser)
 	{
-		float r = rand.floatInRange(-0.5f, 0.5f);
-		r *= velocity_randomiser_weight * 2; // ex. random number [-0.1;0.1]
+		float r = rand.floatInRange(-1.0 * velocity_randomiser_weight,
+		                            velocity_randomiser_weight);
 		level += r;
 		if(level > 1.0)
 		{
 			level = 1.0;
 		}
-
 		if(level < 0.0)
 		{
 			level = 0.0;
@@ -94,8 +93,7 @@ Sample* Instrument::sample(level_t level, size_t pos)
 
 	if(enable_velocity_modifier)
 	{
-		mod += (pos - lastpos) /
-			(samplerate * velocity_modifier_falloff);
+		mod += (pos - lastpos) / (samplerate * velocity_modifier_falloff);
 		if(mod > 1.0)
 		{
 			mod = 1.0;
@@ -113,11 +111,10 @@ Sample* Instrument::sample(level_t level, size_t pos)
 		std::vector<Sample*> s = samples.get(level * mod);
 		if(s.size() == 0)
 		{
-			return NULL;
+			return nullptr;
 		}
 
-		//size_t idx = ::rand()%(s.size());
-		sample = rand.choose<Sample*>(s);
+		sample = rand.choose(s);
 	}
 
 	if(enable_velocity_modifier)
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/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/settings.h b/src/settings.h
index b132c1b..c79e4e5 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -31,10 +31,25 @@
 #include <cassert>
 
 #include "atomic.h"
+#include "notifier.h"
+
+enum class LoadStatus : unsigned int
+{
+	Idle,
+	Loading,
+	Done,
+	Error
+};
 
 //! Engine settings
 struct Settings
 {
+	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};
@@ -51,45 +66,15 @@ struct Settings
 	Atomic<std::string> current_file;
 };
 
-//! Getter utility class.
-template <typename T> class SettingRef
+//! Settings getter class.
+struct SettingsGetter
 {
-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 tmp != cache;
-	}
-
-	T getValue() const
-	{
-		return cache;
-	}
+	SettingRef<std::string> drumkit_file;
+	SettingRef<LoadStatus> drumkit_load_status;
 
-private:
-	bool firstAccess{true};
-	Atomic<T>& value;
-	Atomic<T> cache;
-};
+	SettingRef<std::string> midimap_file;
+	SettingRef<LoadStatus> midimap_load_status;
 
-//! Combined getter class.
-struct SettingsGetter
-{
 	SettingRef<bool> enable_velocity_modifier;
 	SettingRef<float> velocity_modifier_falloff;
 	SettingRef<float> velocity_modifier_weight;
@@ -106,7 +91,11 @@ struct SettingsGetter
 	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}
@@ -120,6 +109,66 @@ struct SettingsGetter
 	}
 };
 
+//! 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<int> number_of_files;
+	Notifier<int> 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 {