Merge branch 'feature_onesix_forge' into develop

25 files changed, 873 insertions, 520 deletions

diff --git a/logic/BaseInstance.cpp b/logic/BaseInstance.cpp
index 10bb4573..ec86596a 100644
--- a/logic/BaseInstance.cpp
+++ b/logic/BaseInstance.cpp
@@ -132,7 +132,7 @@ InstanceList *BaseInstance::instList() const
 		return NULL;
 }
 
-BaseVersionList *BaseInstance::versionList() const
+QSharedPointer<BaseVersionList> BaseInstance::versionList() const
 {
 	return MMC->minecraftlist();
 }
diff --git a/logic/BaseInstance.h b/logic/BaseInstance.h
index fa317ba1..374d1437 100644
--- a/logic/BaseInstance.h
+++ b/logic/BaseInstance.h
@@ -134,7 +134,7 @@ public:
 	 * \brief Gets a pointer to this instance's version list.
 	 * \return A pointer to the available version list for this instance.
 	 */
-	virtual BaseVersionList *versionList() const;
+	virtual QSharedPointer<BaseVersionList> versionList() const;
 	
 	/*!
 	 * \brief Gets this instance's settings object.
diff --git a/logic/ForgeInstaller.cpp b/logic/ForgeInstaller.cpp
new file mode 100644
index 00000000..bcba00e9
--- /dev/null
+++ b/logic/ForgeInstaller.cpp
@@ -0,0 +1,135 @@
+#include "ForgeInstaller.h"
+#include "OneSixVersion.h"
+#include "OneSixLibrary.h"
+#include "net/HttpMetaCache.h"
+#include <quazip.h>
+#include <quazipfile.h>
+#include <pathutils.h>
+#include <QStringList>
+#include "MultiMC.h"
+
+ForgeInstaller::ForgeInstaller(QString filename, QString universal_url)
+{
+	QSharedPointer<OneSixVersion> newVersion;
+	m_universal_url = universal_url;
+
+	QuaZip zip(filename);
+	if (!zip.open(QuaZip::mdUnzip))
+		return;
+
+	QuaZipFile file(&zip);
+
+	// read the install profile
+	if (!zip.setCurrentFile("install_profile.json"))
+		return;
+
+	QJsonParseError jsonError;
+	if (!file.open(QIODevice::ReadOnly))
+		return;
+	QJsonDocument jsonDoc = QJsonDocument::fromJson(file.readAll(), &jsonError);
+	file.close();
+	if (jsonError.error != QJsonParseError::NoError)
+		return;
+
+	if (!jsonDoc.isObject())
+		return;
+
+	QJsonObject root = jsonDoc.object();
+
+	auto installVal = root.value("install");
+	auto versionInfoVal = root.value("versionInfo");
+	if (!installVal.isObject() || !versionInfoVal.isObject())
+		return;
+
+	// read the forge version info
+	{
+		newVersion = OneSixVersion::fromJson(versionInfoVal.toObject());
+		if (!newVersion)
+			return;
+	}
+
+	QJsonObject installObj = installVal.toObject();
+	QString libraryName = installObj.value("path").toString();
+	internalPath = installObj.value("filePath").toString();
+
+	// where do we put the library? decode the mojang path
+	OneSixLibrary lib(libraryName);
+	lib.finalize();
+
+	auto cacheentry = MMC->metacache()->resolveEntry("libraries", lib.storagePath());
+	finalPath = "libraries/" + lib.storagePath();
+	if (!ensureFilePathExists(finalPath))
+		return;
+
+	if (!zip.setCurrentFile(internalPath))
+		return;
+	if (!file.open(QIODevice::ReadOnly))
+		return;
+	{
+		QByteArray data = file.readAll();
+		// extract file
+		QSaveFile extraction(finalPath);
+		if (!extraction.open(QIODevice::WriteOnly))
+			return;
+		if (extraction.write(data) != data.size())
+			return;
+		if (!extraction.commit())
+			return;
+		QCryptographicHash md5sum(QCryptographicHash::Md5);
+		md5sum.addData(data);
+
+		cacheentry->stale = false;
+		cacheentry->md5sum = md5sum.result().toHex().constData();
+		MMC->metacache()->updateEntry(cacheentry);
+	}
+	file.close();
+
+	m_forge_version = newVersion;
+	realVersionId = m_forge_version->id = installObj.value("minecraft").toString();
+}
+
+bool ForgeInstaller::apply(QSharedPointer<OneSixVersion> to)
+{
+	if (!m_forge_version)
+		return false;
+	to->externalUpdateStart();
+	int sliding_insert_window = 0;
+	{
+		// for each library in the version we are adding (except for the blacklisted)
+		QSet<QString> blacklist{"lwjgl", "lwjgl_util", "lwjgl-platform"};
+		for (auto lib : m_forge_version->libraries)
+		{
+			QString libName = lib->name();
+			// if this is the actual forge lib, set an absolute url for the download
+			if (libName.contains("minecraftforge"))
+			{
+				lib->setAbsoluteUrl(m_universal_url);
+			}
+			if (blacklist.contains(libName))
+				continue;
+
+			// find an entry that matches this one
+			bool found = false;
+			for (auto tolib : to->libraries)
+			{
+				if (tolib->name() != libName)
+					continue;
+				found = true;
+				// replace lib
+				tolib = lib;
+				break;
+			}
+			if (!found)
+			{
+				// add lib
+				to->libraries.insert(sliding_insert_window, lib);
+				sliding_insert_window++;
+			}
+		}
+		to->mainClass = m_forge_version->mainClass;
+		to->minecraftArguments = m_forge_version->minecraftArguments;
+		to->processArguments = m_forge_version->processArguments;
+	}
+	to->externalUpdateFinish();
+	return to->toOriginalFile();
+}
diff --git a/logic/ForgeInstaller.h b/logic/ForgeInstaller.h
new file mode 100644
index 00000000..f4ceaaef
--- /dev/null
+++ b/logic/ForgeInstaller.h
@@ -0,0 +1,25 @@
+#pragma once
+#include <QString>
+#include <QSharedPointer>
+
+class OneSixVersion;
+
+class ForgeInstaller
+{
+public:
+	ForgeInstaller(QString filename, QString universal_url);
+
+	bool apply(QSharedPointer<OneSixVersion> to);
+
+private:
+	// the version, read from the installer
+	QSharedPointer<OneSixVersion> m_forge_version;
+	QString internalPath;
+	QString finalPath;
+	QString realVersionId;
+	QString m_universal_url;
+};
+
+
+
+
diff --git a/logic/LegacyUpdate.cpp b/logic/LegacyUpdate.cpp
index 0f58e3e3..84d3d830 100644
--- a/logic/LegacyUpdate.cpp
+++ b/logic/LegacyUpdate.cpp
@@ -60,7 +60,7 @@ void LegacyUpdate::lwjglStart()
 	
 	m_reply = QSharedPointer<QNetworkReply> (rep, &QObject::deleteLater);
 	connect(rep, SIGNAL(downloadProgress(qint64,qint64)), SIGNAL(progress(qint64,qint64)));
-	connect(worker, SIGNAL(finished(QNetworkReply*)), SLOT(lwjglFinished(QNetworkReply*)));
+	connect(worker.data(), SIGNAL(finished(QNetworkReply*)), SLOT(lwjglFinished(QNetworkReply*)));
 	//connect(rep, SIGNAL(error(QNetworkReply::NetworkError)), SLOT(downloadError(QNetworkReply::NetworkError)));
 }
 
@@ -77,7 +77,7 @@ void LegacyUpdate::lwjglFinished(QNetworkReply* reply)
 					"\nSometimes you have to wait a bit if you download many LWJGL versions in a row. YMMV");
 		return;
 	}
-	auto *worker = MMC->qnam();
+	auto worker = MMC->qnam();
 	//Here i check if there is a cookie for me in the reply and extract it
 	QList<QNetworkCookie> cookies = qvariant_cast<QList<QNetworkCookie>>(reply->header(QNetworkRequest::SetCookieHeader));
 	if(cookies.count() != 0)
diff --git a/logic/ModList.h b/logic/ModList.h
index 5395e9ae..e99b6c82 100644
--- a/logic/ModList.h
+++ b/logic/ModList.h
@@ -112,3 +112,6 @@ protected:
 	QString m_list_id;
 	QList<Mod> mods;
 };
+
+
+
diff --git a/logic/NostalgiaInstance.h b/logic/NostalgiaInstance.h
index f2df1828..1436e48d 100644
--- a/logic/NostalgiaInstance.h
+++ b/logic/NostalgiaInstance.h
@@ -9,3 +9,4 @@ public:
 	explicit NostalgiaInstance(const QString &rootDir, SettingsObject * settings, QObject *parent = 0);
 	virtual QString getStatusbarDescription();
 };
+
diff --git a/logic/OneSixInstance.cpp b/logic/OneSixInstance.cpp
index 7b038c46..e22a8890 100644
--- a/logic/OneSixInstance.cpp
+++ b/logic/OneSixInstance.cpp
@@ -2,7 +2,7 @@
 #include "OneSixInstance_p.h"
 #include "OneSixUpdate.h"
 #include "MinecraftProcess.h"
-#include "VersionFactory.h"
+#include "OneSixVersion.h"
 
 #include <setting.h>
 #include <pathutils.h>
@@ -10,8 +10,9 @@
 #include <JlCompress.h>
 #include <gui/OneSixModEditDialog.h>
 
-OneSixInstance::OneSixInstance ( const QString& rootDir, SettingsObject* setting_obj, QObject* parent )
-: BaseInstance ( new OneSixInstancePrivate(), rootDir, setting_obj, parent )
+OneSixInstance::OneSixInstance(const QString &rootDir, SettingsObject *setting_obj,
+							   QObject *parent)
+	: BaseInstance(new OneSixInstancePrivate(), rootDir, setting_obj, parent)
 {
 	I_D(OneSixInstance);
 	d->m_settings->registerSetting(new Setting("IntendedVersion", ""));
@@ -19,7 +20,7 @@ OneSixInstance::OneSixInstance ( const QString& rootDir, SettingsObject* setting
 	reloadFullVersion();
 }
 
-BaseUpdate* OneSixInstance::doUpdate()
+BaseUpdate *OneSixInstance::doUpdate()
 {
 	return new OneSixUpdate(this);
 }
@@ -34,10 +35,10 @@ QString replaceTokensIn(QString text, QMap<QString, QString> with)
 	int head = 0;
 	while ((head = token_regexp.indexIn(text, head)) != -1)
 	{
-		result.append(text.mid(tail, head-tail));
+		result.append(text.mid(tail, head - tail));
 		QString key = token_regexp.cap(1);
 		auto iter = with.find(key);
-		if(iter != with.end())
+		if (iter != with.end())
 		{
 			result.append(*iter);
 		}
@@ -48,26 +49,26 @@ QString replaceTokensIn(QString text, QMap<QString, QString> with)
 	return result;
 }
 
-QStringList OneSixInstance::processMinecraftArgs( QString user, QString session )
+QStringList OneSixInstance::processMinecraftArgs(QString user, QString session)
 {
 	I_D(OneSixInstance);
 	auto version = d->version;
 	QString args_pattern = version->minecraftArguments;
-	
+
 	QMap<QString, QString> token_mapping;
 	token_mapping["auth_username"] = user;
 	token_mapping["auth_session"] = session;
-	//FIXME: user and player name are DIFFERENT!
+	// FIXME: user and player name are DIFFERENT!
 	token_mapping["auth_player_name"] = user;
-	//FIXME: WTF is this. I just plugged in a random UUID here.
+	// FIXME: WTF is this. I just plugged in a random UUID here.
 	token_mapping["auth_uuid"] = "7d4bacf0-fd62-11e2-b778-0800200c9a66"; // obviously fake.
-	
+
 	// this is for offline:
 	/*
 	map["auth_player_name"] = "Player";
 	map["auth_player_name"] = "00000000-0000-0000-0000-000000000000";
 	*/
-	
+
 	token_mapping["profile_name"] = name();
 	token_mapping["version_name"] = version->id;
 
@@ -75,8 +76,8 @@ QStringList OneSixInstance::processMinecraftArgs( QString user, QString session
 	token_mapping["game_directory"] = absRootDir;
 	QString absAssetsDir = QDir("assets/").absolutePath();
 	token_mapping["game_assets"] = absAssetsDir;
-	
-	QStringList parts = args_pattern.split(' ',QString::SkipEmptyParts);
+
+	QStringList parts = args_pattern.split(' ', QString::SkipEmptyParts);
 	for (int i = 0; i < parts.length(); i++)
 	{
 		parts[i] = replaceTokensIn(parts[i], token_mapping);
@@ -84,27 +85,28 @@ QStringList OneSixInstance::processMinecraftArgs( QString user, QString session
 	return parts;
 }
 
-MinecraftProcess* OneSixInstance::prepareForLaunch ( QString user, QString session )
+MinecraftProcess *OneSixInstance::prepareForLaunch(QString user, QString session)
 {
 	I_D(OneSixInstance);
 	cleanupAfterRun();
 	auto version = d->version;
-	if(!version)
+	if (!version)
 		return nullptr;
 	auto libs_to_extract = version->getActiveNativeLibs();
 	QString natives_dir_raw = PathCombine(instanceRoot(), "natives/");
 	bool success = ensureFolderPathExists(natives_dir_raw);
-	if(!success)
+	if (!success)
 	{
 		// FIXME: handle errors
 		return nullptr;
 	}
-	
-	for(auto lib: libs_to_extract)
+
+	for (auto lib : libs_to_extract)
 	{
 		QString path = "libraries/" + lib->storagePath();
 		qDebug() << "Will extract " << path.toLocal8Bit();
-		if(JlCompress::extractWithExceptions(path, natives_dir_raw, lib->extract_excludes).isEmpty())
+		if (JlCompress::extractWithExceptions(path, natives_dir_raw, lib->extract_excludes)
+				.isEmpty())
 		{
 			return nullptr;
 		}
@@ -116,11 +118,11 @@ MinecraftProcess* OneSixInstance::prepareForLaunch ( QString user, QString sessi
 	args << QString("-Xmx%1m").arg(settings().get("MaxMemAlloc").toInt());
 	args << QString("-XX:PermSize=%1m").arg(settings().get("PermGen").toInt());
 	QDir natives_dir(natives_dir_raw);
-	args << QString("-Djava.library.path=%1").arg( natives_dir.absolutePath() );
+	args << QString("-Djava.library.path=%1").arg(natives_dir.absolutePath());
 	QString classPath;
 	{
 		auto libs = version->getActiveNormalLibs();
-		for (auto lib: libs)
+		for (auto lib : libs)
 		{
 			QFileInfo fi(QString("libraries/") + lib->storagePath());
 			classPath.append(fi.absoluteFilePath());
@@ -134,16 +136,16 @@ MinecraftProcess* OneSixInstance::prepareForLaunch ( QString user, QString sessi
 		QFileInfo fi(targetstr);
 		classPath.append(fi.absoluteFilePath());
 	}
-	if(classPath.size())
+	if (classPath.size())
 	{
 		args << "-cp";
 		args << classPath;
 	}
 	args << version->mainClass;
 	args.append(processMinecraftArgs(user, session));
-	
+
 	// create the process and set its parameters
-	MinecraftProcess * proc = new MinecraftProcess(this);
+	MinecraftProcess *proc = new MinecraftProcess(this);
 	proc->setMinecraftArguments(args);
 	proc->setMinecraftWorkdir(minecraftRoot());
 	return proc;
@@ -156,10 +158,10 @@ void OneSixInstance::cleanupAfterRun()
 	dir.removeRecursively();
 }
 
-QSharedPointer< ModList > OneSixInstance::loaderModList()
+QSharedPointer<ModList> OneSixInstance::loaderModList()
 {
 	I_D(OneSixInstance);
-	if(!d->loader_mod_list)
+	if (!d->loader_mod_list)
 	{
 		d->loader_mod_list.reset(new ModList(loaderModsDir()));
 	}
@@ -168,10 +170,10 @@ QSharedPointer< ModList > OneSixInstance::loaderModList()
 	return d->loader_mod_list;
 }
 
-QSharedPointer< ModList > OneSixInstance::resourcePackList()
+QSharedPointer<ModList> OneSixInstance::resourcePackList()
 {
 	I_D(OneSixInstance);
-	if(!d->resource_pack_list)
+	if (!d->resource_pack_list)
 	{
 		d->resource_pack_list.reset(new ModList(resourcePacksDir()));
 	}
@@ -180,13 +182,12 @@ QSharedPointer< ModList > OneSixInstance::resourcePackList()
 	return d->resource_pack_list;
 }
 
-
-QDialog * OneSixInstance::createModEditDialog ( QWidget* parent )
+QDialog *OneSixInstance::createModEditDialog(QWidget *parent)
 {
 	return new OneSixModEditDialog(this, parent);
 }
 
-bool OneSixInstance::setIntendedVersionId ( QString version )
+bool OneSixInstance::setIntendedVersionId(QString version)
 {
 	settings().set("IntendedVersion", version);
 	setShouldUpdate(true);
@@ -198,16 +199,16 @@ QString OneSixInstance::intendedVersionId() const
 	return settings().get("IntendedVersion").toString();
 }
 
-void OneSixInstance::setShouldUpdate ( bool val )
+void OneSixInstance::setShouldUpdate(bool val)
 {
-	settings().set ( "ShouldUpdate", val );
+	settings().set("ShouldUpdate", val);
 }
 
 bool OneSixInstance::shouldUpdate() const
 {
 	I_D(OneSixInstance);
-	QVariant var = settings().get ( "ShouldUpdate" );
-	if ( !var.isValid() || var.toBool() == false )
+	QVariant var = settings().get("ShouldUpdate");
+	if (!var.isValid() || var.toBool() == false)
 	{
 		return intendedVersionId() != currentVersionId();
 	}
@@ -226,34 +227,53 @@ QString OneSixInstance::currentVersionId() const
 	return intendedVersionId();
 }
 
+bool OneSixInstance::customizeVersion()
+{
+	if (!versionIsCustom())
+	{
+		auto pathCustom = PathCombine(instanceRoot(), "custom.json");
+		auto pathOrig = PathCombine(instanceRoot(), "version.json");
+		QFile::copy(pathOrig, pathCustom);
+		return reloadFullVersion();
+	}
+	else
+		return true;
+}
+
+bool OneSixInstance::revertCustomVersion()
+{
+	if (versionIsCustom())
+	{
+		auto path = PathCombine(instanceRoot(), "custom.json");
+		QFile::remove(path);
+		return reloadFullVersion();
+	}
+	else
+		return true;
+}
+
 bool OneSixInstance::reloadFullVersion()
 {
 	I_D(OneSixInstance);
-	
+
 	QString verpath = PathCombine(instanceRoot(), "version.json");
 	{
 		QString verpath_custom = PathCombine(instanceRoot(), "custom.json");
 		QFile versionfile(verpath_custom);
-		if(versionfile.exists())
+		if (versionfile.exists())
 			verpath = verpath_custom;
 	}
-	
-	QFile versionfile(verpath);
-	if(versionfile.exists() && versionfile.open(QIODevice::ReadOnly))
+
+	auto version = OneSixVersion::fromFile(verpath);
+	if (version)
 	{
-		FullVersionFactory fvf;
-		auto version = fvf.parse(versionfile.readAll());
-		versionfile.close();
-		if(version)
-		{
-			d->version = version;
-			return true;
-		}
-	};
+		d->version = version;
+		return true;
+	}
 	return false;
 }
 
-QSharedPointer< OneSixVersion > OneSixInstance::getFullVersion()
+QSharedPointer<OneSixVersion> OneSixInstance::getFullVersion()
 {
 	I_D(OneSixInstance);
 	return d->version;
@@ -269,9 +289,9 @@ QString OneSixInstance::defaultCustomBaseJar() const
 	return PathCombine(instanceRoot(), "custom.jar");
 }
 
-bool OneSixInstance::menuActionEnabled ( QString action_name ) const
+bool OneSixInstance::menuActionEnabled(QString action_name) const
 {
-	if(action_name == "actionChangeInstLWJGLVersion")
+	if (action_name == "actionChangeInstLWJGLVersion")
 		return false;
 	return true;
 }
@@ -279,7 +299,7 @@ bool OneSixInstance::menuActionEnabled ( QString action_name ) const
 QString OneSixInstance::getStatusbarDescription()
 {
 	QString descr = "One Six : " + intendedVersionId();
-	if(versionIsCustom())
+	if (versionIsCustom())
 	{
 		descr + " (custom)";
 	}
@@ -300,3 +320,4 @@ QString OneSixInstance::instanceConfigFolder() const
 {
 	return PathCombine(minecraftRoot(), "config");
 }
+
diff --git a/logic/OneSixInstance.h b/logic/OneSixInstance.h
index 72bde630..0139b645 100644
--- a/logic/OneSixInstance.h
+++ b/logic/OneSixInstance.h
@@ -41,6 +41,10 @@ public:
 	bool reloadFullVersion();
 	/// get the current full version info
 	QSharedPointer<OneSixVersion> getFullVersion();
+	/// revert the current custom version back to base
+	bool revertCustomVersion();
+	/// customize the current base version
+	bool customizeVersion();
 	/// is the current version original, or custom?
 	bool versionIsCustom();
 	
diff --git a/logic/OneSixLibrary.cpp b/logic/OneSixLibrary.cpp
index a45a4aec..8da1fde7 100644
--- a/logic/OneSixLibrary.cpp
+++ b/logic/OneSixLibrary.cpp
@@ -1,18 +1,19 @@
 #include "OneSixLibrary.h"
 #include "OneSixRule.h"
 #include "OpSys.h"
+#include <QJsonArray>
 void OneSixLibrary::finalize()
 {
-	QStringList parts = m_name.split ( ':' );
+	QStringList parts = m_name.split(':');
 	QString relative = parts[0];
-	relative.replace ( '.','/' );
+	relative.replace('.', '/');
 	relative += '/' + parts[1] + '/' + parts[2] + '/' + parts[1] + '-' + parts[2];
-	
-	if ( !m_is_native )
+
+	if (!m_is_native)
 		relative += ".jar";
 	else
 	{
-		if ( m_native_suffixes.contains ( currentSystem ) )
+		if (m_native_suffixes.contains(currentSystem))
 		{
 			relative += "-" + m_native_suffixes[currentSystem] + ".jar";
 		}
@@ -22,30 +23,30 @@ void OneSixLibrary::finalize()
 			relative += ".jar";
 		}
 	}
-	
+
 	m_decentname = parts[1];
 	m_decentversion = parts[2];
 	m_storage_path = relative;
-	m_download_path = m_base_url + relative;
-	
-	if ( m_rules.empty() )
+	m_download_url = m_base_url + relative;
+
+	if (m_rules.empty())
 	{
 		m_is_active = true;
 	}
 	else
 	{
 		RuleAction result = Disallow;
-		for ( auto rule: m_rules )
+		for (auto rule : m_rules)
 		{
-			RuleAction temp = rule->apply ( this );
-			if ( temp != Defer )
+			RuleAction temp = rule->apply(this);
+			if (temp != Defer)
 				result = temp;
 		}
-		m_is_active = ( result == Allow );
+		m_is_active = (result == Allow);
 	}
-	if ( m_is_native )
+	if (m_is_native)
 	{
-		m_is_active = m_is_active && m_native_suffixes.contains ( currentSystem );
+		m_is_active = m_is_active && m_native_suffixes.contains(currentSystem);
 		m_decenttype = "Native";
 	}
 	else
@@ -54,11 +55,11 @@ void OneSixLibrary::finalize()
 	}
 }
 
-void OneSixLibrary::setName ( QString name )
+void OneSixLibrary::setName(QString name)
 {
 	m_name = name;
 }
-void OneSixLibrary::setBaseUrl ( QString base_url )
+void OneSixLibrary::setBaseUrl(QString base_url)
 {
 	m_base_url = base_url;
 }
@@ -66,12 +67,12 @@ void OneSixLibrary::setIsNative()
 {
 	m_is_native = true;
 }
-void OneSixLibrary::addNative ( OpSys os, QString suffix )
+void OneSixLibrary::addNative(OpSys os, QString suffix)
 {
 	m_is_native = true;
 	m_native_suffixes[os] = suffix;
 }
-void OneSixLibrary::setRules ( QList< QSharedPointer< Rule > > rules )
+void OneSixLibrary::setRules(QList<QSharedPointer<Rule>> rules)
 {
 	m_rules = rules;
 }
@@ -83,11 +84,66 @@ bool OneSixLibrary::isNative()
 {
 	return m_is_native;
 }
-QString OneSixLibrary::downloadPath()
+QString OneSixLibrary::downloadUrl()
 {
-	return m_download_path;
+	if(m_absolute_url.size())
+		return m_absolute_url;
+	return m_download_url;
 }
 QString OneSixLibrary::storagePath()
 {
 	return m_storage_path;
 }
+
+void OneSixLibrary::setAbsoluteUrl(QString absolute_url)
+{
+	m_absolute_url = absolute_url;
+}
+
+QString OneSixLibrary::absoluteUrl()
+{
+	return m_absolute_url;
+}
+
+QJsonObject OneSixLibrary::toJson()
+{
+	QJsonObject libRoot;
+	libRoot.insert("name", m_name);
+	if(m_absolute_url.size())
+		libRoot.insert("MMC-absulute_url", m_absolute_url);
+	if(m_base_url != "https://s3.amazonaws.com/Minecraft.Download/libraries/")
+		libRoot.insert("url", m_base_url);
+	if (isNative() && m_native_suffixes.size())
+	{
+		QJsonObject nativeList;
+		auto iter = m_native_suffixes.begin();
+		while (iter != m_native_suffixes.end())
+		{
+			nativeList.insert(OpSys_toString(iter.key()), iter.value());
+			iter++;
+		}
+		libRoot.insert("natives", nativeList);
+	}
+	if (isNative() && extract_excludes.size())
+	{
+		QJsonArray excludes;
+		QJsonObject extract;
+		for (auto exclude : extract_excludes)
+		{
+			excludes.append(exclude);
+		}
+		extract.insert("exclude", excludes);
+		libRoot.insert("extract", extract);
+	}
+	if (m_rules.size())
+	{
+		QJsonArray allRules;
+		for (auto &rule : m_rules)
+		{
+			QJsonObject ruleObj = rule->toJson();
+			allRules.append(ruleObj);
+		}
+		libRoot.insert("rules", allRules);
+	}
+	return libRoot;
+}
diff --git a/logic/OneSixLibrary.h b/logic/OneSixLibrary.h
index ac16d3d3..f3106483 100644
--- a/logic/OneSixLibrary.h
+++ b/logic/OneSixLibrary.h
@@ -3,6 +3,7 @@
 #include <QStringList>
 #include <QMap>
 #include <QSharedPointer>
+#include <QJsonObject>
 #include "OpSys.h"
 
 class Rule;
@@ -12,9 +13,13 @@ class OneSixLibrary
 private:
 	// basic values used internally (so far)
 	QString m_name;
-	QString m_base_url;
+	QString m_base_url = "https://s3.amazonaws.com/Minecraft.Download/libraries/";
 	QList<QSharedPointer<Rule> > m_rules;
-	
+
+	// custom values
+	/// absolute URL. takes precedence over m_download_path, if defined
+	QString m_absolute_url;
+
 	// derived values used for real things
 	/// a decent name fit for display
 	QString m_decentname;
@@ -25,11 +30,11 @@ private:
 	/// where to store the lib locally
 	QString m_storage_path;
 	/// where to download the lib from
-	QString m_download_path;
+	QString m_download_url;
 	/// is this lib actually active on the current OS?
-	bool m_is_active;
+	bool m_is_active = false;
 	/// is the library a native?
-	bool m_is_native;
+	bool m_is_native = false;
 	/// native suffixes per OS
 	QMap<OpSys, QString> m_native_suffixes;
 public:
@@ -39,12 +44,11 @@ public:
 	/// Constructor
 	OneSixLibrary(QString name)
 	{
-		m_is_native = false;
-		m_is_active = false;
 		m_name = name;
-		m_base_url = "https://s3.amazonaws.com/Minecraft.Download/libraries/";
 	}
 	
+	QJsonObject toJson();
+	
 	/**
 	 * finalize the library, processing the input values into derived values and state
 	 * 
@@ -84,7 +88,11 @@ public:
 	/// Returns true if the library is native
 	bool isNative();
 	/// Get the URL to download the library from
-	QString downloadPath();
+	QString downloadUrl();
 	/// Get the relative path where the library should be saved
 	QString storagePath();
+	
+	/// set an absolute URL for the library. This is an MMC extension.
+	void setAbsoluteUrl(QString absolute_url);
+	QString absoluteUrl();
 };
diff --git a/logic/OneSixRule.cpp b/logic/OneSixRule.cpp
index 85f7d434..545cd641 100644
--- a/logic/OneSixRule.cpp
+++ b/logic/OneSixRule.cpp
@@ -1,10 +1,72 @@
 #include "OneSixRule.h"
+#include <QJsonObject>
+#include <QJsonArray>
+
+QList<QSharedPointer<Rule>> rulesFromJsonV4(QJsonObject &objectWithRules)
+{
+	QList<QSharedPointer<Rule>> rules;
+	auto rulesVal = objectWithRules.value("rules");
+	if (!rulesVal.isArray())
+		return rules;
+
+	QJsonArray ruleList = rulesVal.toArray();
+	for (auto ruleVal : ruleList)
+	{
+		QSharedPointer<Rule> rule;
+		if (!ruleVal.isObject())
+			continue;
+		auto ruleObj = ruleVal.toObject();
+		auto actionVal = ruleObj.value("action");
+		if (!actionVal.isString())
+			continue;
+		auto action = RuleAction_fromString(actionVal.toString());
+		if (action == Defer)
+			continue;
+
+		auto osVal = ruleObj.value("os");
+		if (!osVal.isObject())
+		{
+			// add a new implicit action rule
+			rules.append(ImplicitRule::create(action));
+			continue;
+		}
+
+		auto osObj = osVal.toObject();
+		auto osNameVal = osObj.value("name");
+		if (!osNameVal.isString())
+			continue;
+		OpSys requiredOs = OpSys_fromString(osNameVal.toString());
+		QString versionRegex = osObj.value("version").toString();
+		// add a new OS rule
+		rules.append(OsRule::create(action, requiredOs, versionRegex));
+	}
+}
+
+QJsonObject ImplicitRule::toJson()
+{
+	QJsonObject ruleObj;
+	ruleObj.insert("action", m_result == Allow ? QString("allow") : QString("disallow"));
+	return ruleObj;
+}
+
+QJsonObject OsRule::toJson()
+{
+	QJsonObject ruleObj;
+	ruleObj.insert("action", m_result == Allow ? QString("allow") : QString("disallow"));
+	QJsonObject osObj;
+	{
+		osObj.insert("name", OpSys_toString(m_system));
+		osObj.insert("version", m_version_regexp);
+	}
+	ruleObj.insert("os", osObj);
+	return ruleObj;
+}
 
 RuleAction RuleAction_fromString(QString name)
 {
-	if(name == "allow")
+	if (name == "allow")
 		return Allow;
-	if(name == "disallow")
+	if (name == "disallow")
 		return Disallow;
 	return Defer;
 }
\ No newline at end of file
diff --git a/logic/OneSixRule.h b/logic/OneSixRule.h
index 465c963f..23d20ff4 100644
--- a/logic/OneSixRule.h
+++ b/logic/OneSixRule.h
@@ -1,8 +1,6 @@
 #pragma once
 #include <QString>
 #include <QSharedPointer>
-
-class OneSixLibrary;
 #include "OneSixLibrary.h"