NOISSUE Fix jar mods for OnesSix

23 files changed, 436 insertions, 881 deletions

diff --git a/logic/BaseInstance.cpp b/logic/BaseInstance.cpp
index 1dc5b671..b23dde73 100644
--- a/logic/BaseInstance.cpp
+++ b/logic/BaseInstance.cpp
@@ -15,7 +15,6 @@
 
 #include "MultiMC.h"
 #include "BaseInstance.h"
-#include "BaseInstance_p.h"
 
 #include <QFileInfo>
 #include <QDir>
@@ -31,61 +30,50 @@
 #include "logic/icons/IconList.h"
 #include "logic/InstanceList.h"
 
-BaseInstance::BaseInstance(BaseInstancePrivate *d_in, const QString &rootDir,
-						   SettingsObject *settings_obj, QObject *parent)
-	: QObject(parent), inst_d(d_in)
+BaseInstance::BaseInstance(const QString &rootDir, SettingsObject *settings, QObject *parent)
+	: QObject(parent)
 {
-	I_D(BaseInstance);
-	d->m_settings = std::shared_ptr<SettingsObject>(settings_obj);
-	d->m_rootDir = rootDir;
 
-	settings().registerSetting("name", "Unnamed Instance");
-	settings().registerSetting("iconKey", "default");
+	m_settings = std::shared_ptr<SettingsObject>(settings);
+	m_rootDir = rootDir;
+
+	m_settings->registerSetting("name", "Unnamed Instance");
+	m_settings->registerSetting("iconKey", "default");
 	connect(MMC->icons().get(), SIGNAL(iconUpdated(QString)), SLOT(iconUpdated(QString)));
-	settings().registerSetting("notes", "");
-	settings().registerSetting("lastLaunchTime", 0);
-
-	/*
-	 * custom base jar has no default. it is determined in code... see the accessor methods for
-	 *it
-	 *
-	 * for instances that DO NOT have the CustomBaseJar setting (legacy instances),
-	 * [.]minecraft/bin/mcbackup.jar is the default base jar
-	 */
-	settings().registerSetting("UseCustomBaseJar", true);
-	settings().registerSetting("CustomBaseJar", "");
+	m_settings->registerSetting("notes", "");
+	m_settings->registerSetting("lastLaunchTime", 0);
 
 	auto globalSettings = MMC->settings();
 
 	// Java Settings
-	settings().registerSetting("OverrideJava", false);
-	settings().registerSetting("OverrideJavaLocation", false);
-	settings().registerSetting("OverrideJavaArgs", false);
-	settings().registerOverride(globalSettings->getSetting("JavaPath"));
-	settings().registerOverride(globalSettings->getSetting("JvmArgs"));
+	m_settings->registerSetting("OverrideJava", false);
+	m_settings->registerSetting("OverrideJavaLocation", false);
+	m_settings->registerSetting("OverrideJavaArgs", false);
+	m_settings->registerOverride(globalSettings->getSetting("JavaPath"));
+	m_settings->registerOverride(globalSettings->getSetting("JvmArgs"));
 
 	// Custom Commands
-	settings().registerSetting({"OverrideCommands","OverrideLaunchCmd"}, false);
-	settings().registerOverride(globalSettings->getSetting("PreLaunchCommand"));
-	settings().registerOverride(globalSettings->getSetting("PostExitCommand"));
+	m_settings->registerSetting({"OverrideCommands","OverrideLaunchCmd"}, false);
+	m_settings->registerOverride(globalSettings->getSetting("PreLaunchCommand"));
+	m_settings->registerOverride(globalSettings->getSetting("PostExitCommand"));
 
 	// Window Size
-	settings().registerSetting("OverrideWindow", false);
-	settings().registerOverride(globalSettings->getSetting("LaunchMaximized"));
-	settings().registerOverride(globalSettings->getSetting("MinecraftWinWidth"));
-	settings().registerOverride(globalSettings->getSetting("MinecraftWinHeight"));
+	m_settings->registerSetting("OverrideWindow", false);
+	m_settings->registerOverride(globalSettings->getSetting("LaunchMaximized"));
+	m_settings->registerOverride(globalSettings->getSetting("MinecraftWinWidth"));
+	m_settings->registerOverride(globalSettings->getSetting("MinecraftWinHeight"));
 
 	// Memory
-	settings().registerSetting("OverrideMemory", false);
-	settings().registerOverride(globalSettings->getSetting("MinMemAlloc"));
-	settings().registerOverride(globalSettings->getSetting("MaxMemAlloc"));
-	settings().registerOverride(globalSettings->getSetting("PermGen"));
+	m_settings->registerSetting("OverrideMemory", false);
+	m_settings->registerOverride(globalSettings->getSetting("MinMemAlloc"));
+	m_settings->registerOverride(globalSettings->getSetting("MaxMemAlloc"));
+	m_settings->registerOverride(globalSettings->getSetting("PermGen"));
 
 	// Console
-	settings().registerSetting("OverrideConsole", false);
-	settings().registerOverride(globalSettings->getSetting("ShowConsole"));
-	settings().registerOverride(globalSettings->getSetting("AutoCloseConsole"));
-	settings().registerOverride(globalSettings->getSetting("LogPrePostOutput"));
+	m_settings->registerSetting("OverrideConsole", false);
+	m_settings->registerOverride(globalSettings->getSetting("ShowConsole"));
+	m_settings->registerOverride(globalSettings->getSetting("AutoCloseConsole"));
+	m_settings->registerOverride(globalSettings->getSetting("LogPrePostOutput"));
 }
 
 void BaseInstance::iconUpdated(QString key)
@@ -109,26 +97,22 @@ QString BaseInstance::id() const
 
 bool BaseInstance::isRunning() const
 {
-	I_D(BaseInstance);
-	return d->m_isRunning;
+	return m_isRunning;
 }
 
-void BaseInstance::setRunning(bool running) const
+void BaseInstance::setRunning(bool running)
 {
-	I_D(BaseInstance);
-	d->m_isRunning = running;
+	m_isRunning = running;
 }
 
 QString BaseInstance::instanceType() const
 {
-	I_D(BaseInstance);
-	return d->m_settings->get("InstanceType").toString();
+	return m_settings->get("InstanceType").toString();
 }
 
 QString BaseInstance::instanceRoot() const
 {
-	I_D(BaseInstance);
-	return d->m_rootDir;
+	return m_rootDir;
 }
 
 QString BaseInstance::minecraftRoot() const
@@ -159,36 +143,34 @@ std::shared_ptr<BaseVersionList> BaseInstance::versionList() const
 
 SettingsObject &BaseInstance::settings() const
 {
-	I_D(BaseInstance);
-	return *d->m_settings;
+	return *m_settings;
 }
 
 BaseInstance::InstanceFlags BaseInstance::flags() const
 {
-	I_D(const BaseInstance);
-	return d->m_flags;
+	return m_flags;
 }
+
 void BaseInstance::setFlags(const InstanceFlags &flags)
 {
-	I_D(BaseInstance);
-	if (flags != d->m_flags)
+	if (flags != m_flags)
 	{
-		d->m_flags = flags;
+		m_flags = flags;
 		emit flagsChanged();
 		emit propertiesChanged(this);
 	}
 }
+
 void BaseInstance::setFlag(const BaseInstance::InstanceFlag flag)
 {
-	I_D(BaseInstance);
-	d->m_flags |= flag;
+	m_flags |= flag;
 	emit flagsChanged();
 	emit propertiesChanged(this);
 }
+
 void BaseInstance::unsetFlag(const BaseInstance::InstanceFlag flag)
 {
-	I_D(BaseInstance);
-	d->m_flags &= ~flag;
+	m_flags &= ~flag;
 	emit flagsChanged();
 	emit propertiesChanged(this);
 }
@@ -200,69 +182,23 @@ bool BaseInstance::canLaunch() const
 
 bool BaseInstance::reload()
 {
-	return settings().reload();
-}
-
-QString BaseInstance::baseJar() const
-{
-	I_D(BaseInstance);
-	bool customJar = d->m_settings->get("UseCustomBaseJar").toBool();
-	if (customJar)
-	{
-		return customBaseJar();
-	}
-	else
-		return defaultBaseJar();
-}
-
-QString BaseInstance::customBaseJar() const
-{
-	I_D(BaseInstance);
-	QString value = d->m_settings->get("CustomBaseJar").toString();
-	if (value.isNull() || value.isEmpty())
-	{
-		return defaultCustomBaseJar();
-	}
-	return value;
-}
-
-void BaseInstance::setCustomBaseJar(QString val)
-{
-	I_D(BaseInstance);
-	if (val.isNull() || val.isEmpty() || val == defaultCustomBaseJar())
-		d->m_settings->reset("CustomBaseJar");
-	else
-		d->m_settings->set("CustomBaseJar", val);
-}
-
-void BaseInstance::setShouldUseCustomBaseJar(bool val)
-{
-	I_D(BaseInstance);
-	d->m_settings->set("UseCustomBaseJar", val);
-}
-
-bool BaseInstance::shouldUseCustomBaseJar() const
-{
-	I_D(BaseInstance);
-	return d->m_settings->get("UseCustomBaseJar").toBool();
+	return m_settings->reload();
 }
 
 qint64 BaseInstance::lastLaunch() const
 {
-	I_D(BaseInstance);
-	return d->m_settings->get("lastLaunchTime").value<qint64>();
+	return m_settings->get("lastLaunchTime").value<qint64>();
 }
+
 void BaseInstance::setLastLaunch(qint64 val)
 {
-	I_D(BaseInstance);
-	d->m_settings->set("lastLaunchTime", val);
+	m_settings->set("lastLaunchTime", val);
 	emit propertiesChanged(this);
 }
 
 void BaseInstance::setGroupInitial(QString val)
 {
-	I_D(BaseInstance);
-	d->m_group = val;
+	m_group = val;
 	emit propertiesChanged(this);
 }
 
@@ -274,44 +210,39 @@ void BaseInstance::setGroupPost(QString val)
 
 QString BaseInstance::group() const
 {
-	I_D(BaseInstance);
-	return d->m_group;
+	return m_group;
 }
 
 void BaseInstance::setNotes(QString val)
 {
-	I_D(BaseInstance);
-	d->m_settings->set("notes", val);
+	m_settings->set("notes", val);
 }
+
 QString BaseInstance::notes() const
 {
-	I_D(BaseInstance);
-	return d->m_settings->get("notes").toString();
+	return m_settings->get("notes").toString();
 }
 
 void BaseInstance::setIconKey(QString val)
 {
-	I_D(BaseInstance);
-	d->m_settings->set("iconKey", val);
+	m_settings->set("iconKey", val);
 	emit propertiesChanged(this);
 }
+
 QString BaseInstance::iconKey() const
 {
-	I_D(BaseInstance);
-	return d->m_settings->get("iconKey").toString();
+	return m_settings->get("iconKey").toString();
 }
 
 void BaseInstance::setName(QString val)
 {
-	I_D(BaseInstance);
-	d->m_settings->set("name", val);
+	m_settings->set("name", val);
 	emit propertiesChanged(this);
 }
 
 QString BaseInstance::name() const
 {
-	I_D(BaseInstance);
-	return d->m_settings->get("name").toString();
+	return m_settings->get("name").toString();
 }
 
 QString BaseInstance::windowTitle() const
diff --git a/logic/BaseInstance.h b/logic/BaseInstance.h
index c8517298..a0ac3c57 100644
--- a/logic/BaseInstance.h
+++ b/logic/BaseInstance.h
@@ -51,8 +51,7 @@ class BaseInstance : public QObject
 	Q_OBJECT
 protected:
 	/// no-touchy!
-	BaseInstance(BaseInstancePrivate *d, const QString &rootDir, SettingsObject *settings,
-				 QObject *parent = 0);
+	BaseInstance(const QString &rootDir, SettingsObject *settings, QObject *parent = 0);
 
 public:
 	/// virtual destructor to make sure the destruction is COMPLETE
@@ -69,8 +68,8 @@ public:
 	/// be unique.
 	virtual QString id() const;
 
-	virtual void setRunning(bool running) const;
-	virtual bool isRunning() const;
+	void setRunning(bool running);
+	bool isRunning() const;
 
 	/// get the type of this instance
 	QString instanceType() const;
@@ -127,30 +126,10 @@ public:
 	{
 		return nullptr;
 	}
-	
+
 	/// Traits. Normally inside the version, depends on instance implementation.
 	virtual QSet <QString> traits() = 0;
 
-	/// Get the curent base jar of this instance. By default, it's the
-	/// versions/$version/$version.jar
-	QString baseJar() const;
-
-	/// the default base jar of this instance
-	virtual QString defaultBaseJar() const = 0;
-	/// the default custom base jar of this instance
-	virtual QString defaultCustomBaseJar() const = 0;
-
-	/*!
-	 * Whether or not custom base jar is used
-	 */
-	bool shouldUseCustomBaseJar() const;
-	void setShouldUseCustomBaseJar(bool val);
-	/*!
-	 * The value of the custom base jar
-	 */
-	QString customBaseJar() const;
-	void setCustomBaseJar(QString val);
-
 	/**
 	 * Gets the time that the instance was last launched.
 	 * Stored in milliseconds since epoch.
@@ -202,7 +181,7 @@ public:
 		VersionBrokenFlag = 0x01,
 		UpdateAvailable = 0x02
 	};
-	Q_DECLARE_FLAGS(InstanceFlags, InstanceFlag)
+	Q_DECLARE_FLAGS(InstanceFlags, InstanceFlag);
 	InstanceFlags flags() const;
 	void setFlags(const InstanceFlags &flags);
 	void setFlag(const InstanceFlag flag);
@@ -232,7 +211,11 @@ protected slots:
 	void iconUpdated(QString key);
 
 protected:
-	std::shared_ptr<BaseInstancePrivate> inst_d;
+	QString m_rootDir;
+	QString m_group;
+	std::shared_ptr<SettingsObject> m_settings;
+	InstanceFlags m_flags;
+	bool m_isRunning = false;
 };
 
 Q_DECLARE_METATYPE(std::shared_ptr<BaseInstance>)
diff --git a/logic/BaseInstance_p.h b/logic/BaseInstance_p.h
deleted file mode 100644
index 2958e4e8..00000000
--- a/logic/BaseInstance_p.h
+++ /dev/null
@@ -1,36 +0,0 @@
-/* Copyright 2013-2014 MultiMC Contributors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#pragma once
-
-#include <QString>
-#include <QSet>
-
-#include "logic/settings/SettingsObject.h"
-
-#include "BaseInstance.h"
-
-#define I_D(Class) Class##Private *const d = (Class##Private * const)inst_d.get()
-
-class BaseInstancePrivate
-{
-public:
-    virtual ~BaseInstancePrivate(){};
-	QString m_rootDir;
-	QString m_group;
-	std::shared_ptr<SettingsObject> m_settings;
-	BaseInstance::InstanceFlags m_flags;
-	bool m_isRunning = false;
-};
diff --git a/logic/InstanceFactory.cpp b/logic/InstanceFactory.cpp
index 640c02f3..832b8387 100644
--- a/logic/InstanceFactory.cpp
+++ b/logic/InstanceFactory.cpp
@@ -100,7 +100,6 @@ InstanceFactory::InstCreateError InstanceFactory::createInstance(InstancePtr &in
 		m_settings->set("InstanceType", "OneSix");
 		inst.reset(new OneSixInstance(instDir, m_settings));
 		inst->setIntendedVersionId(version->descriptor());
-		inst->setShouldUseCustomBaseJar(false);
 	}
 	else if (type == FTBInstance)
 	{
@@ -109,14 +108,12 @@ InstanceFactory::InstCreateError InstanceFactory::createInstance(InstancePtr &in
 			m_settings->set("InstanceType", "LegacyFTB");
 			inst.reset(new LegacyFTBInstance(instDir, m_settings));
 			inst->setIntendedVersionId(version->descriptor());
-			inst->setShouldUseCustomBaseJar(false);
 		}
 		else
 		{
 			m_settings->set("InstanceType", "OneSixFTB");
 			inst.reset(new OneSixFTBInstance(instDir, m_settings));
 			inst->setIntendedVersionId(version->descriptor());
-			inst->setShouldUseCustomBaseJar(false);
 		}
 	}
 	else
diff --git a/logic/InstanceLauncher.cpp b/logic/InstanceLauncher.cpp
deleted file mode 100644
index 4e47c592..00000000
--- a/logic/InstanceLauncher.cpp
+++ /dev/null
@@ -1,94 +0,0 @@
-/* Copyright 2013-2014 MultiMC Contributors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <iostream>
-
-#include "InstanceLauncher.h"
-#include "MultiMC.h"
-
-#include "gui/ConsoleWindow.h"
-#include "gui/dialogs/ProgressDialog.h"
-
-#include "logic/MinecraftProcess.h"
-#include "logic/InstanceList.h"
-
-InstanceLauncher::InstanceLauncher(QString instId) : QObject(), instId(instId)
-{
-}
-
-void InstanceLauncher::onTerminated()
-{
-	std::cout << "Minecraft exited" << std::endl;
-	MMC->quit();
-}
-
-void InstanceLauncher::onLoginComplete()
-{
-	// TODO: Fix this.
-	/*
-	LoginTask *task = (LoginTask *)QObject::sender();
-	auto result = task->getResult();
-	auto instance = MMC->instances()->getInstanceById(instId);
-	proc = instance->prepareForLaunch(result);
-	if (!proc)
-	{
-		// FIXME: report error
-		return;
-	}
-	console = new ConsoleWindow(proc);
-	connect(console, SIGNAL(isClosing()), this, SLOT(onTerminated()));
-
-	proc->setLogin(result.username, result.session_id);
-	proc->launch();
-	*/
-}
-
-void InstanceLauncher::doLogin(const QString &errorMsg)
-{
-	// FIXME: Use new account system here...
-	/*
-	LoginDialog *loginDlg = new LoginDialog(nullptr, errorMsg);
-	loginDlg->exec();
-	if (loginDlg->result() == QDialog::Accepted)
-	{
-		PasswordLogin uInfo{loginDlg->getUsername(), loginDlg->getPassword()};
-
-		ProgressDialog *tDialog = new ProgressDialog(nullptr);
-		LoginTask *loginTask = new LoginTask(uInfo, tDialog);
-		connect(loginTask, SIGNAL(succeeded()), SLOT(onLoginComplete()), Qt::QueuedConnection);
-		connect(loginTask, SIGNAL(failed(QString)), SLOT(doLogin(QString)),
-				Qt::QueuedConnection);
-		tDialog->exec(loginTask);
-	}
-	*/
-	// onLoginComplete(LoginResponse("Offline","Offline", 1));
-}
-
-int InstanceLauncher::launch()
-{
-	std::cout << "Launching Instance '" << qPrintable(instId) << "'" << std::endl;
-	auto instance = MMC->instances()->getInstanceById(instId);
-	if (!instance)
-	{
-		std::cout << "Could not find instance requested. note that you have to specify the ID, "
-					 "not the NAME" << std::endl;
-		return 1;
-	}
-
-	std::cout << "Logging in..." << std::endl;
-	doLogin("");
-
-	return MMC->exec();
-}
diff --git a/logic/InstanceLauncher.h b/logic/InstanceLauncher.h
deleted file mode 100644
index 07f86b99..00000000
--- a/logic/InstanceLauncher.h
+++ /dev/null
@@ -1,44 +0,0 @@
-/* Copyright 2013-2014 MultiMC Contributors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#pragma once
-
-#include <QObject>
-
-class MinecraftProcess;
-class ConsoleWindow;
-
-// Commandline instance launcher
-class InstanceLauncher : public QObject
-{
-	Q_OBJECT
-
-private:
-	QString instId;
-	MinecraftProcess *proc;
-	ConsoleWindow *console;
-
-public:
-	InstanceLauncher(QString instId);
-
-private
-slots:
-	void onTerminated();
-	void onLoginComplete();
-	void doLogin(const QString &errorMsg);
-
-public:
-	int launch();
-};
diff --git a/logic/JarUtils.cpp b/logic/JarUtils.cpp
new file mode 100644
index 00000000..3b4f780a
--- /dev/null
+++ b/logic/JarUtils.cpp
@@ -0,0 +1,161 @@
+#include "JarUtils.h"
+#include <quazip.h>
+#include <quazipfile.h>
+#include <JlCompress.h>
+#include <logger/QsLog.h>
+
+namespace JarUtils {
+
+bool mergeZipFiles(QuaZip *into, QFileInfo from, QSet<QString> &contained,
+				   std::function<bool(QString)> filter)
+{
+	QuaZip modZip(from.filePath());
+	modZip.open(QuaZip::mdUnzip);
+
+	QuaZipFile fileInsideMod(&modZip);
+	QuaZipFile zipOutFile(into);
+	for (bool more = modZip.goToFirstFile(); more; more = modZip.goToNextFile())
+	{
+		QString filename = modZip.getCurrentFileName();
+		if (!filter(filename))
+		{
+			QLOG_INFO() << "Skipping file " << filename << " from "
+						<< from.fileName() << " - filtered";
+			continue;
+		}
+		if (contained.contains(filename))
+		{
+			QLOG_INFO() << "Skipping already contained file " << filename << " from "
+						<< from.fileName();
+			continue;
+		}
+		contained.insert(filename);
+		QLOG_INFO() << "Adding file " << filename << " from " << from.fileName();
+
+		if (!fileInsideMod.open(QIODevice::ReadOnly))
+		{
+			QLOG_ERROR() << "Failed to open " << filename << " from " << from.fileName();
+			return false;
+		}
+
+		QuaZipNewInfo info_out(fileInsideMod.getActualFileName());
+
+		if (!zipOutFile.open(QIODevice::WriteOnly, info_out))
+		{
+			QLOG_ERROR() << "Failed to open " << filename << " in the jar";
+			fileInsideMod.close();
+			return false;
+		}
+		if (!JlCompress::copyData(fileInsideMod, zipOutFile))
+		{
+			zipOutFile.close();
+			fileInsideMod.close();
+			QLOG_ERROR() << "Failed to copy data of " << filename << " into the jar";
+			return false;
+		}
+		zipOutFile.close();
+		fileInsideMod.close();
+	}
+	return true;
+}
+
+bool createModdedJar(QString sourceJarPath, QString targetJarPath, const QList<Mod>& mods)
+{
+	QuaZip zipOut(targetJarPath);
+	if (!zipOut.open(QuaZip::mdCreate))
+	{
+		QFile::remove(targetJarPath);
+		QLOG_ERROR() << "Failed to open the minecraft.jar for modding";
+		return false;
+	}
+	// Files already added to the jar.
+	// These files will be skipped.
+	QSet<QString> addedFiles;
+
+	// Modify the jar
+	QListIterator<Mod> i(mods);
+    i.toBack();
+    while (i.hasPrevious())
+	{
+		const Mod &mod = i.previous();
+		// do not merge disabled mods.
+		if (!mod.enabled())
+			continue;
+		if (mod.type() == Mod::MOD_ZIPFILE)
+		{
+			if (!mergeZipFiles(&zipOut, mod.filename(), addedFiles, noFilter))
+			{
+				zipOut.close();
+				QFile::remove(targetJarPath);
+				QLOG_ERROR() << "Failed to add" << mod.filename().fileName() << "to the jar.";
+				return false;
+			}
+		}
+		else if (mod.type() == Mod::MOD_SINGLEFILE)
+		{
+			auto filename = mod.filename();
+			if (!JlCompress::compressFile(&zipOut, filename.absoluteFilePath(),
+										  filename.fileName()))
+			{
+				zipOut.close();
+				QFile::remove(targetJarPath);
+				QLOG_ERROR() << "Failed to add" << mod.filename().fileName() << "to the jar.";
+				return false;
+			}
+			addedFiles.insert(filename.fileName());
+			QLOG_INFO() << "Adding file " << filename.fileName() << " from "
+						<< filename.absoluteFilePath();
+		}
+		else if (mod.type() == Mod::MOD_FOLDER)
+		{
+			auto filename = mod.filename();
+			QString what_to_zip = filename.absoluteFilePath();
+			QDir dir(what_to_zip);
+			dir.cdUp();
+			QString parent_dir = dir.absolutePath();
+			if (!JlCompress::compressSubDir(&zipOut, what_to_zip, parent_dir, true, addedFiles))
+			{
+				zipOut.close();
+				QFile::remove(targetJarPath);
+				QLOG_ERROR() << "Failed to add" << mod.filename().fileName() << "to the jar.";
+				return false;
+			}
+			QLOG_INFO() << "Adding folder " << filename.fileName() << " from "
+						<< filename.absoluteFilePath();
+		}
+	}
+
+	if (!mergeZipFiles(&zipOut, QFileInfo(sourceJarPath), addedFiles, metaInfFilter))
+	{
+		zipOut.close();
+		QFile::remove(targetJarPath);
+		QLOG_ERROR() << "Failed to insert minecraft.jar contents.";
+		return false;
+	}
+
+	// Recompress the jar
+	zipOut.close();
+	if (zipOut.getZipError() != 0)
+	{
+		QFile::remove(targetJarPath);
+		QLOG_ERROR() << "Failed to finalize minecraft.jar!";
+		return false;
+	}
+	return true;
+}
+
+bool noFilter(QString)
+{
+	return true;
+}
+
+bool metaInfFilter(QString key)
+{
+	if(key.contains("META-INF"))
+	{
+		return false;
+	}
+	return true;
+}
+
+}
diff --git a/logic/JarUtils.h b/logic/JarUtils.h
new file mode 100644
index 00000000..2e8bd2a7
--- /dev/null
+++ b/logic/JarUtils.h
@@ -0,0 +1,18 @@
+#pragma once
+#include <QString>
+#include <QFileInfo>
+#include <QSet>
+#include "Mod.h"
+#include <functional>
+
+class QuaZip;
+namespace JarUtils
+{
+	bool noFilter(QString);
+	bool metaInfFilter(QString key);
+
+	bool mergeZipFiles(QuaZip *into, QFileInfo from, QSet<QString> &contained,
+				   std::function<bool(QString)> filter);
+
+	bool createModdedJar(QString sourceJarPath, QString targetJarPath, const QList<Mod>& mods);
+}
diff --git a/logic/LegacyInstance.cpp b/logic/LegacyInstance.cpp
index 468110da..7752229a 100644
--- a/logic/LegacyInstance.cpp
+++ b/logic/LegacyInstance.cpp
@@ -23,7 +23,6 @@
 #include "MultiMC.h"
 
 #include "LegacyInstance.h"
-#include "LegacyInstance_p.h"
 
 #include "logic/MinecraftProcess.h"
 #include "logic/LegacyUpdate.h"
@@ -36,15 +35,23 @@
 #include <gui/pages/NotesPage.h>
 #include <gui/pages/ScreenshotsPage.h>
 
-LegacyInstance::LegacyInstance(const QString &rootDir, SettingsObject *settings,
-							   QObject *parent)
-	: BaseInstance(new LegacyInstancePrivate(), rootDir, settings, parent)
+LegacyInstance::LegacyInstance(const QString &rootDir, SettingsObject *settings, QObject *parent)
+	: BaseInstance(rootDir, settings, parent)
 {
 	settings->registerSetting("NeedsRebuild", true);
 	settings->registerSetting("ShouldUpdate", false);
 	settings->registerSetting("JarVersion", "Unknown");
 	settings->registerSetting("LwjglVersion", "2.9.0");
 	settings->registerSetting("IntendedJarVersion", "");
+	/*
+	 * custom base jar has no default. it is determined in code... see the accessor methods for
+	 *it
+	 *
+	 * for instances that DO NOT have the CustomBaseJar setting (legacy instances),
+	 * [.]minecraft/bin/mcbackup.jar is the default base jar
+	 */
+	settings->registerSetting("UseCustomBaseJar", true);
+	settings->registerSetting("CustomBaseJar", "");
 }
 
 QList<BasePage *> LegacyInstance::getPages()
@@ -69,6 +76,46 @@ QString LegacyInstance::dialogTitle()
 	return tr("Edit Instance (%1)").arg(name());
 }
 
+QString LegacyInstance::baseJar() const
+{
+	bool customJar = m_settings->get("UseCustomBaseJar").toBool();
+	if (customJar)
+	{
+		return customBaseJar();
+	}
+	else
+		return defaultBaseJar();
+}
+
+QString LegacyInstance::customBaseJar() const
+{
+	QString value = m_settings->get("CustomBaseJar").toString();
+	if (value.isNull() || value.isEmpty())
+	{
+		return defaultCustomBaseJar();
+	}
+	return value;
+}
+
+void LegacyInstance::setCustomBaseJar(QString val)
+{
+	if (val.isNull() || val.isEmpty() || val == defaultCustomBaseJar())
+		m_settings->reset("CustomBaseJar");
+	else
+		m_settings->set("CustomBaseJar", val);
+}
+
+void LegacyInstance::setShouldUseCustomBaseJar(bool val)
+{
+	m_settings->set("UseCustomBaseJar", val);
+}
+
+bool LegacyInstance::shouldUseCustomBaseJar() const
+{
+	return m_settings->get("UseCustomBaseJar").toBool();
+}
+
+
 std::shared_ptr<Task> LegacyInstance::doUpdate()
 {
 	// make sure the jar mods list is initialized by asking for it.
@@ -113,26 +160,24 @@ void LegacyInstance::cleanupAfterRun()
 
 std::shared_ptr<ModList> LegacyInstance::coreModList()
 {
-	I_D(LegacyInstance);
-	if (!d->core_mod_list)
+	if (!core_mod_list)
 	{
-		d->core_mod_list.reset(new ModList(coreModsDir()));
+		core_mod_list.reset(new ModList(coreModsDir()));
 	}
-	d->core_mod_list->update();
-	return d->core_mod_list;
+	core_mod_list->update();
+	return core_mod_list;
 }
 
 std::shared_ptr<ModList> LegacyInstance::jarModList()
 {
-	I_D(LegacyInstance);
-	if (!d->jar_mod_list)
+	if (!jar_mod_list)
 	{
 		auto list = new ModList(jarModsDir(), modListFile());
 		connect(list, SIGNAL(changed()), SLOT(jarModsChanged()));
-		d->jar_mod_list.reset(list);
+		jar_mod_list.reset(list);
 	}
-	d->jar_mod_list->update();
-	return d->jar_mod_list;
+	jar_mod_list->update();
+	return jar_mod_list;
 }
 
 void LegacyInstance::jarModsChanged()
@@ -143,24 +188,22 @@ void LegacyInstance::jarModsChanged()
 
 std::shared_ptr<ModList> LegacyInstance::loaderModList()
 {
-	I_D(LegacyInstance);
-	if (!d->loader_mod_list)
+	if (!loader_mod_list)
 	{
-		d->loader_mod_list.reset(new ModList(loaderModsDir()));
+		loader_mod_list.reset(new ModList(loaderModsDir()));
 	}
-	d->loader_mod_list->update();
-	return d->loader_mod_list;
+	loader_mod_list->update();
+	return loader_mod_list;
 }
 
 std::shared_ptr<ModList> LegacyInstance::texturePackList()
 {
-	I_D(LegacyInstance);
-	if (!d->texture_pack_list)
+	if (!texture_pack_list)
 	{
-		d->texture_pack_list.reset(new ModList(texturePacksDir()));
+		texture_pack_list.reset(new ModList(texturePacksDir()));
 	}
-	d->texture_pack_list->update();
-	return d->texture_pack_list;
+	texture_pack_list->update();
+	return texture_pack_list;
 }
 
 QString LegacyInstance::jarModsDir() const
@@ -219,38 +262,32 @@ QString LegacyInstance::instanceConfigFolder() const
 
 bool LegacyInstance::shouldRebuild() const
 {
-	I_D(LegacyInstance);
-	return d->m_settings->get("NeedsRebuild").toBool();
+	return m_settings->get("NeedsRebuild").toBool();
 }
 
 void LegacyInstance::setShouldRebuild(bool val)
 {
-	I_D(LegacyInstance);
-	d->m_settings->set("NeedsRebuild", val);
+	m_settings->set("NeedsRebuild", val);
 }
 
 QString LegacyInstance::currentVersionId() const
 {
-	I_D(LegacyInstance);
-	return d->m_settings->get("JarVersion").toString();
+	return m_settings->get("JarVersion").toString();
 }
 
 QString LegacyInstance::lwjglVersion() const
 {
-	I_D(LegacyInstance);
-	return d->m_settings->get("LwjglVersion").toString();
+	return m_settings->get("LwjglVersion").toString();
 }
 
 void LegacyInstance::setLWJGLVersion(QString val)
 {
-	I_D(LegacyInstance);
-	d->m_settings->set("LwjglVersion", val);
+	m_settings->set("LwjglVersion", val);
 }
 
 QString LegacyInstance::intendedVersionId() const
 {
-	I_D(LegacyInstance);
-	return d->m_settings->get("IntendedJarVersion").toString();
+	return m_settings->get("IntendedJarVersion").toString();
 }
 
 bool LegacyInstance::setIntendedVersionId(QString version)
diff --git a/logic/LegacyInstance.h b/logic/LegacyInstance.h
index d21d2ff4..b91be7c1 100644
--- a/logic/LegacyInstance.h
+++ b/logic/LegacyInstance.h
@@ -56,6 +56,27 @@ public:
 	QString resourceDir() const;
 	virtual QString instanceConfigFolder() const override;
 
+		/// Get the curent base jar of this instance. By default, it's the
+	/// versions/$version/$version.jar
+	QString baseJar() const;
+
+	/// the default base jar of this instance
+	QString defaultBaseJar() const;
+	/// the default custom base jar of this instance
+	QString defaultCustomBaseJar() const;
+
+	/*!
+	 * Whether or not custom base jar is used
+	 */
+	bool shouldUseCustomBaseJar() const;
+	void setShouldUseCustomBaseJar(bool val);
+
+	/*!
+	 * The value of the custom base jar
+	 */
+	QString customBaseJar() const;
+	void setCustomBaseJar(QString val);
+
 	/*!
 	 * Whether or not the instance's minecraft.jar needs to be rebuilt.
 	 * If this is true, when the instance launches, its jar mods will be
@@ -92,11 +113,14 @@ public:
 	virtual bool prepareForLaunch(AuthSessionPtr account, QString & launchScript) override;
 	virtual void cleanupAfterRun() override;
 
-	virtual QString defaultBaseJar() const override;
-	virtual QString defaultCustomBaseJar() const override;
-
 	virtual QString getStatusbarDescription() override;
 
+protected:
+	std::shared_ptr<ModList> jar_mod_list;
+	std::shared_ptr<ModList> core_mod_list;
+	std::shared_ptr<ModList> loader_mod_list;
+	std::shared_ptr<ModList> texture_pack_list;
+
 protected
 slots:
 	virtual void jarModsChanged();
diff --git a/logic/LegacyInstance_p.h b/logic/LegacyInstance_p.h
deleted file mode 100644
index 83bcecc5..00000000
--- a/logic/LegacyInstance_p.h
+++ /dev/null
@@ -1,32 +0,0 @@
-/* Copyright 2013-2014 MultiMC Contributors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#pragma once
-#include <QString>
-#include "logic/settings/SettingsObject.h"
-#include <memory>
-
-#include "BaseInstance_p.h"
-#include "ModList.h"
-
-class LegacyInstancePrivate : public BaseInstancePrivate
-{
-public:
-	virtual ~LegacyInstancePrivate() {};
-	std::shared_ptr<ModList> jar_mod_list;
-	std::shared_ptr<ModList> core_mod_list;
-	std::shared_ptr<ModList> loader_mod_list;
-	std::shared_ptr<ModList> texture_pack_list;
-};
diff --git a/logic/LegacyUpdate.cpp b/logic/LegacyUpdate.cpp
index de5c19c0..10128f57 100644
--- a/logic/LegacyUpdate.cpp
+++ b/logic/LegacyUpdate.cpp
@@ -30,6 +30,7 @@
 
 #include "logger/QsLog.h"
 #include "logic/net/URLConstants.h"
+#include "JarUtils.h"
 
 
 LegacyUpdate::LegacyUpdate(BaseInstance *inst, QObject *parent) : Task(parent), m_inst(inst)
@@ -38,25 +39,7 @@ LegacyUpdate::LegacyUpdate(BaseInstance *inst, QObject *parent) : Task(parent),
 
 void LegacyUpdate::executeTask()
 {
-	/*
-	if(m_only_prepare)
-	{
-		// FIXME: think this through some more.
-		LegacyInstance *inst = (LegacyInstance *)m_inst;
-		if (!inst->shouldUpdate() || inst->shouldUseCustomBaseJar())
-		{
-			ModTheJar();
-		}
-		else
-		{
-			emitSucceeded();
-		}
-	}
-	else
-	{
-		*/
 	fmllibsStart();
-	//}
 }
 
 void LegacyUpdate::fmllibsStart()
@@ -415,65 +398,6 @@ void LegacyUpdate::jarFailed()
 	emitFailed("Failed to download the minecraft jar. Try again later.");
 }
 
-bool LegacyUpdate::MergeZipFiles(QuaZip *into, QFileInfo from, QSet<QString> &contained,
-								 MetainfAction metainf)
-{
-	setStatus(tr("Installing mods: Adding ") + from.fileName() + " ...");
-
-	QuaZip modZip(from.filePath());
-	modZip.open(QuaZip::mdUnzip);
-
-	QuaZipFile fileInsideMod(&modZip);
-	QuaZipFile zipOutFile(into);
-	for (bool more = modZip.goToFirstFile(); more; more = modZip.goToNextFile())
-	{
-		QString filename = modZip.getCurrentFileName();
-		if (filename.contains("META-INF") && metainf == LegacyUpdate::IgnoreMetainf)
-		{
-			QLOG_INFO() << "Skipping META-INF " << filename << " from " << from.fileName();
-			continue;
-		}
-		if (contained.contains(filename))
-		{
-			QLOG_INFO() << "Skipping already contained file " << filename << " from "
-						<< from.fileName();
-			continue;
-		}
-		contained.insert(filename);
-		QLOG_INFO() << "Adding file " << filename << " from " << from.fileName();
-
-		if (!fileInsideMod.open(QIODevice::ReadOnly))
-		{
-			QLOG_ERROR() << "Failed to open " << filename << " from " << from.fileName();
-			return false;
-		}
-		/*
-		QuaZipFileInfo old_info;
-		fileInsideMod.getFileInfo(&old_info);
-		*/
-		QuaZipNewInfo info_out(fileInsideMod.getActualFileName());
-		/*
-		info_out.externalAttr = old_info.externalAttr;
-		*/
-		if (!zipOutFile.open(QIODevice::WriteOnly, info_out))
-		{
-			QLOG_ERROR() << "Failed to open " << filename << " in the jar";
-			fileInsideMod.close();
-			return false;
-		}
-		if (!JlCompress::copyData(fileInsideMod, zipOutFile))
-		{
-			zipOutFile.close();
-			fileInsideMod.close();
-			QLOG_ERROR() << "Failed to copy data of " << filename << " into the jar";
-			return false;
-		}
-		zipOutFile.close();
-		fileInsideMod.close();
-	}
-	return true;
-}
-
 void LegacyUpdate::ModTheJar()
 {
 	LegacyInstance *inst = (LegacyInstance *)m_inst;
@@ -531,85 +455,13 @@ void LegacyUpdate::ModTheJar()
 	// TaskStep(); // STEP 1
 	setStatus(tr("Installing mods: Opening minecraft.jar ..."));
 
-	QuaZip zipOut(runnableJar.filePath());
-	if (!zipOut.open(QuaZip::mdCreate))
-	{
-		QFile::remove(runnableJar.filePath());
-		emitFailed("Failed to open the minecraft.jar for modding");
-		return;
-	}
-	// Files already added to the jar.
-	// These files will be skipped.
-	QSet<QString> addedFiles;
-
-	// Modify the jar
-	setStatus(tr("Installing mods: Adding mod files..."));
-	for (int i = modList->size() - 1; i >= 0; i--)
-	{
-		auto &mod = modList->operator[](i);
-
-		// do not merge disabled mods.
-		if (!mod.enabled())
-			continue;
-
-		if (mod.type() == Mod::MOD_ZIPFILE)
-		{
-			if (!MergeZipFiles(&zipOut, mod.filename(), addedFiles, LegacyUpdate::KeepMetainf))
-			{
-				zipOut.close();
-				QFile::remove(runnableJar.filePath());
-				emitFailed("Failed to add " + mod.filename().fileName() + " to the jar.");
-				return;
-			}
-		}
-		else if (mod.type() == Mod::MOD_SINGLEFILE)
-		{
-			auto filename = mod.filename();
-			if (!JlCompress::compressFile(&zipOut, filename.absoluteFilePath(),
-										  filename.fileName()))
-			{
-				zipOut.close();
-				QFile::remove(runnableJar.filePath());
-				emitFailed("Failed to add " + filename.fileName() + " to the jar");
-				return;
-			}
-			addedFiles.insert(filename.fileName());
-			QLOG_INFO() << "Adding file " << filename.fileName() << " from "
-						<< filename.absoluteFilePath();
-		}
-		else if (mod.type() == Mod::MOD_FOLDER)
-		{
-			auto filename = mod.filename();
-			QString what_to_zip = filename.absoluteFilePath();
-			QDir dir(what_to_zip);
-			dir.cdUp();
-			QString parent_dir = dir.absolutePath();
-			if (!JlCompress::compressSubDir(&zipOut, what_to_zip, parent_dir, true, addedFiles))
-			{
-				zipOut.close();
-				QFile::remove(runnableJar.filePath());
-				emitFailed("Failed to add " + filename.fileName() + " to the jar");
-				return;
-			}
-			QLOG_INFO() << "Adding folder " << filename.fileName() << " from "
-						<< filename.absoluteFilePath();
-		}
-	}
-
-	if (!MergeZipFiles(&zipOut, baseJar, addedFiles, LegacyUpdate::IgnoreMetainf))
-	{
-		zipOut.close();
-		QFile::remove(runnableJar.filePath());
-		emitFailed("Failed to insert minecraft.jar contents.");
-		return;
-	}
+	const auto & mods = modList->allMods();
+	QString outputJarPath = runnableJar.filePath();
+	QString inputJarPath = baseJar.filePath();
 
-	// Recompress the jar
-	zipOut.close();
-	if (zipOut.getZipError() != 0)
+	if(!JarUtils::createModdedJar(inputJarPath, outputJarPath, mods))
 	{
-		QFile::remove(runnableJar.filePath());
-		emitFailed("Failed to finalize minecraft.jar!");
+		emitFailed(tr("Failed to create the custom Minecraft jar file."));
 		return;
 	}
 	inst->setShouldRebuild(false);
diff --git a/logic/LegacyUpdate.h b/logic/LegacyUpdate.h
index da538d2f..8041305a 100644
--- a/logic/LegacyUpdate.h
+++ b/logic/LegacyUpdate.h
@@ -54,15 +54,6 @@ slots:
 	void ModTheJar();
 
 private:
-	enum MetainfAction
-	{
-		KeepMetainf,  // the META-INF folder will be added from the merged jar
-		IgnoreMetainf // the META-INF from the merged jar will be ignored
-	};
-	bool MergeZipFiles(QuaZip *into, QFileInfo from, QSet<QString> &contained,
-					   MetainfAction metainf);
-
-private:
 
 	std::shared_ptr<QNetworkReply> m_reply;
 
diff --git a/logic/ModList.h b/logic/ModList.h
index e7320df5..2409a31a 100644
--- a/logic/ModList.h
+++ b/logic/ModList.h
@@ -126,6 +126,11 @@ public:
 		return m_dir;
 	}
 
+	const QList<Mod> & allMods()
+	{
+		return mods;
+	}
+
 private:
 	void internalSort(QList<Mod> & what);
 	struct OrderItem
diff --git a/logic/OneSixFTBInstance.cpp b/logic/OneSixFTBInstance.cpp
index d1585155..bf1361dd 100644
--- a/logic/OneSixFTBInstance.cpp
+++ b/logic/OneSixFTBInstance.cpp
@@ -6,7 +6,6 @@
 #include "tasks/SequentialTask.h"
 #include "forge/ForgeInstaller.h"
 #include "forge/ForgeVersionList.h"
-#include "OneSixInstance_p.h"
 #include "MultiMC.h"
 #include "pathutils.h"
 
diff --git a/logic/OneSixInstance.cpp b/logic/OneSixInstance.cpp
index dbf47ffb..40b87d9e 100644
--- a/logic/OneSixInstance.cpp
+++ b/logic/OneSixInstance.cpp
@@ -21,7 +21,6 @@
 
 #include "logic/OneSixInstance.h"
 
-#include "logic/OneSixInstance_p.h"
 #include "logic/OneSixUpdate.h"
 #include "logic/minecraft/InstanceVersion.h"
 #include "minecraft/VersionBuildError.h"
@@ -39,13 +38,11 @@
 #include "gui/pages/ScreenshotsPage.h"
 #include "gui/pages/OtherLogsPage.h"
 
-OneSixInstance::OneSixInstance(const QString &rootDir, SettingsObject *settings,
-							   QObject *parent)
-	: BaseInstance(new OneSixInstancePrivate(), rootDir, settings, parent)
+OneSixInstance::OneSixInstance(const QString &rootDir, SettingsObject *settings, QObject *parent)
+	: BaseInstance(rootDir, settings, parent)
 {
-	I_D(OneSixInstance);
-	d->m_settings->registerSetting("IntendedVersion", "");
-	d->version.reset(new InstanceVersion(this, this));
+	m_settings->registerSetting("IntendedVersion", "");
+	version.reset(new InstanceVersion(this, this));
 }
 
 void OneSixInstance::init()
@@ -184,8 +181,6 @@ QDir OneSixInstance::reconstructAssets(std::shared_ptr<InstanceVersion> version)
 
 QStringList OneSixInstance::processMinecraftArgs(AuthSessionPtr session)
 {
-	I_D(OneSixInstance);
-	auto version = d->version;
 	QString args_pattern = version->minecraftArguments;
 	for (auto tweaker : version->tweakers)
 	{
@@ -207,7 +202,7 @@ QStringList OneSixInstance::processMinecraftArgs(AuthSessionPtr session)
 	QString absRootDir = QDir(minecraftRoot()).absolutePath();
 	token_mapping["game_directory"] = absRootDir;
 	QString absAssetsDir = QDir("assets/").absolutePath();
-	token_mapping["game_assets"] = reconstructAssets(d->version).absolutePath();
+	token_mapping["game_assets"] = reconstructAssets(version).absolutePath();
 
 	token_mapping["user_properties"] = session->serializeUserProperties();
 	token_mapping["user_type"] = session->user_type;
@@ -225,13 +220,11 @@ QStringList OneSixInstance::processMinecraftArgs(AuthSessionPtr session)
 
 bool OneSixInstance::prepareForLaunch(AuthSessionPtr session, QString &launchScript)
 {
-	I_D(OneSixInstance);
 
 	QIcon icon = MMC->icons()->getIcon(iconKey());
 	auto pixmap = icon.pixmap(128, 128);
 	pixmap.save(PathCombine(minecraftRoot(), "icon.png"), "PNG");
 
-	auto version = d->version;
 	if (!version)
 		return nullptr;
 
@@ -242,20 +235,15 @@ bool OneSixInstance::prepareForLaunch(AuthSessionPtr session, QString &launchScr
 		{
 			launchScript += "cp " + librariesPath().absoluteFilePath(lib->storagePath()) + "\n";
 		}
-		QString minecraftjarpath;
 		if (version->hasJarMods())
 		{
-			for (auto jarmod : version->jarMods)
-			{
-				launchScript += "cp " + jarmodsPath().absoluteFilePath(jarmod->name) + "\n";
-			}
-			minecraftjarpath = version->id + "/" + version->id + "-stripped.jar";
+			launchScript += "cp " + QDir(instanceRoot()).absoluteFilePath("temp.jar") + "\n";
 		}
 		else
 		{
-			minecraftjarpath = version->id + "/" + version->id + ".jar";
+			QString relpath = version->id + "/" + version->id + ".jar";
+			launchScript += "cp " + versionsPath().absoluteFilePath(relpath) + "\n";
 		}
-		launchScript += "cp " + versionsPath().absoluteFilePath(minecraftjarpath) + "\n";
 	}
 	if (!version->mainClass.isEmpty())
 	{
@@ -320,46 +308,42 @@ void OneSixInstance::cleanupAfterRun()
 
 std::shared_ptr<ModList> OneSixInstance::loaderModList()
 {
-	I_D(OneSixInstance);
-	if (!d->loader_mod_list)
+	if (!loader_mod_list)
 	{
-		d->loader_mod_list.reset(new ModList(loaderModsDir()));
+		loader_mod_list.reset(new ModList(loaderModsDir()));
 	}
-	d->loader_mod_list->update();
-	return d->loader_mod_list;
+	loader_mod_list->update();
+	return loader_mod_list;
 }
 
 std::shared_ptr<ModList> OneSixInstance::coreModList()
 {
-	I_D(OneSixInstance);
-	if (!d->core_mod_list)
+	if (!core_mod_list)
 	{
-		d->core_mod_list.reset(new ModList(coreModsDir()));
+		core_mod_list.reset(new ModList(coreModsDir()));
 	}
-	d->core_mod_list->update();
-	return d->core_mod_list;
+	core_mod_list->update();
+	return core_mod_list;
 }
 
 std::shared_ptr<ModList> OneSixInstance::resourcePackList()
 {
-	I_D(OneSixInstance);
-	if (!d->resource_pack_list)
+	if (!resource_pack_list)
 	{
-		d->resource_pack_list.reset(new ModList(resourcePacksDir()));
+		resource_pack_list.reset(new ModList(resourcePacksDir()));
 	}
-	d->resource_pack_list->update();
-	return d->resource_pack_list;
+	resource_pack_list->update();
+	return resource_pack_list;
 }
 
 std::shared_ptr<ModList> OneSixInstance::texturePackList()
 {
-	I_D(OneSixInstance);
-	if (!d->texture_pack_list)
+	if (!texture_pack_list)
 	{
-		d->texture_pack_list.reset(new ModList(texturePacksDir()));
+		texture_pack_list.reset(new ModList(texturePacksDir()));
 	}
-	d->texture_pack_list->update();
-	return d->texture_pack_list;
+	texture_pack_list->update();
+	return texture_pack_list;
 }
 
 bool OneSixInstance::setIntendedVersionId(QString version)
@@ -386,22 +370,18 @@ bool OneSixInstance::shouldUpdate() const
 
 bool OneSixInstance::versionIsCustom()
 {
-	I_D(const OneSixInstance);
-	auto ver = d->version;
-	if (ver)
+	if (version)
 	{
-		return !ver->isVanilla();
+		return !version->isVanilla();
 	}
 	return false;
 }
 
 bool OneSixInstance::versionIsFTBPack()
 {
-	I_D(const OneSixInstance);
-	auto ver = d->version;
-	if (ver)
+	if (version)
 	{
-		return ver->hasFtbPack();
+		return version->hasFtbPack();
 	}
 	return false;
 }
@@ -413,11 +393,10 @@ QString OneSixInstance::currentVersionId() const
 
 void OneSixInstance::reloadVersion()
 {
-	I_D(OneSixInstance);
 
 	try
 	{
-		d->version->reload(externalPatches());
+		version->reload(externalPatches());
 		unsetFlag(VersionBrokenFlag);
 		emit versionReloaded();
 	}
@@ -426,7 +405,7 @@ void OneSixInstance::reloadVersion()
 	}
 	catch (MMCError &error)
 	{
-		d->version->clear();
+		version->clear();
 		setFlag(VersionBrokenFlag);
 		// TODO: rethrow to show some error message(s)?
 		emit versionReloaded();
@@ -436,25 +415,13 @@ void OneSixInstance::reloadVersion()
 
 void OneSixInstance::clearVersion()
 {
-	I_D(OneSixInstance);
-	d->version->clear();
+	version->clear();
 	emit versionReloaded();
 }
 
 std::shared_ptr<InstanceVersion> OneSixInstance::getFullVersion() const
 {
-	I_D(const OneSixInstance);
-	return d->version;
-}
-
-QString OneSixInstance::defaultBaseJar() const
-{
-	return "versions/" + intendedVersionId() + "/" + intendedVersionId() + ".jar";
-}
-
-QString OneSixInstance::defaultCustomBaseJar() const
-{
-	return PathCombine(instanceRoot(), "custom.jar");
+	return version;
 }
 
 QString OneSixInstance::getStatusbarDescription()
diff --git a/logic/OneSixInstance.h b/logic/OneSixInstance.h
index d751ffc8..70726208 100644
--- a/logic/OneSixInstance.h
+++ b/logic/OneSixInstance.h
@@ -42,7 +42,7 @@ public:
 	std::shared_ptr<ModList> texturePackList() override;
 
 	virtual QSet<QString> traits();
-	
+
 	////// Directories and files //////
 	QString jarModsDir() const;
 	QString resourcePacksDir() const;
@@ -67,26 +67,23 @@ public:
 
 	/**
 	 * reload the full version json files.
-	 * 
+	 *
 	 * throws various exceptions :3
 	 */
 	void reloadVersion();
-	
+
 	/// clears all version information in preparation for an update
 	void clearVersion();
-	
+
 	/// get the current full version info
 	std::shared_ptr<InstanceVersion> getFullVersion() const;
-	
+
 	/// is the current version original, or custom?
 	virtual bool versionIsCustom() override;
-	
+
 	/// does this instance have an FTB pack patch inside?
 	bool versionIsFTBPack();
 
-	virtual QString defaultBaseJar() const override;
-	virtual QString defaultCustomBaseJar() const override;
-
 	virtual QString getStatusbarDescription() override;
 
 	virtual QDir jarmodsPath() const;
@@ -107,6 +104,14 @@ signals:
 private:
 	QStringList processMinecraftArgs(AuthSessionPtr account);
 	QDir reconstructAssets(std::shared_ptr<InstanceVersion> version);
+
+protected:
+	std::shared_ptr<InstanceVersion> version;
+	std::shared_ptr<ModList> jar_mod_list;
+	std::shared_ptr<ModList> loader_mod_list;
+	std::shared_ptr<ModList> core_mod_list;
+	std::shared_ptr<ModList> resource_pack_list;
+	std::shared_ptr<ModList> texture_pack_list;
 };
 
 Q_DECLARE_METATYPE(std::shared_ptr<OneSixInstance>)
diff --git a/logic/OneSixInstance_p.h b/logic/OneSixInstance_p.h
deleted file mode 100644
index 3fa12baf..00000000
--- a/logic/OneSixInstance_p.h
+++ /dev/null
@@ -1,33 +0,0 @@
-/* Copyright 2013-2014 MultiMC Contributors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#pragma once
-
-#include "logic/BaseInstance_p.h"
-
-class ModList;
-class InstanceVersion;
-
-class OneSixInstancePrivate : public BaseInstancePrivate
-{
-public:
-	virtual ~OneSixInstancePrivate() {};
-	std::shared_ptr<InstanceVersion> version;
-	std::shared_ptr<ModList> jar_mod_list;
-	std::shared_ptr<ModList> loader_mod_list;
-	std::shared_ptr<ModList> core_mod_list;
-	std::shared_ptr<ModList> resource_pack_list;
-	std::shared_ptr<ModList> texture_pack_list;
-};
diff --git a/logic/OneSixUpdate.cpp b/logic/OneSixUpdate.cpp
index 380d5dab..fe8cf3b5 100644
--- a/logic/OneSixUpdate.cpp
+++ b/logic/OneSixUpdate.cpp
@@ -33,6 +33,7 @@
 #include "logic/forge/ForgeMirrors.h"
 #include "logic/net/URLConstants.h"
 #include "logic/assets/AssetsUtils.h"
+#include "JarUtils.h"
 
 OneSixUpdate::OneSixUpdate(OneSixInstance *inst, QObject *parent) : Task(parent), m_inst(inst)
 {
@@ -287,23 +288,44 @@ void OneSixUpdate::jarlibFinished()
 	OneSixInstance *inst = (OneSixInstance *)m_inst;
 	std::shared_ptr<InstanceVersion> version = inst->getFullVersion();
 
+	// nuke obsolete stripped jar(s) if needed
+	QString version_id = version->id;
+	QString strippedPath = version_id + "/" + version_id + "-stripped.jar";
+	QFile strippedJar(strippedPath);
+	if(strippedJar.exists())
+	{
+		strippedJar.remove();
+	}
+	auto finalJarPath = QDir(m_inst->instanceRoot()).absoluteFilePath("temp.jar");
+	QFile finalJar(finalJarPath);
+	if(finalJar.exists())
+	{
+		if(!finalJar.remove())
+		{
+			emitFailed(tr("Couldn't remove stale jar file: %1").arg(finalJarPath));
+			return;
+		}
+	}
+
 	// create stripped jar, if needed
 	if (version->hasJarMods())
 	{
-		// FIXME: good candidate for moving elsewhere (jar location resolving/version caching).
-		QString version_id = version->id;
+		auto sourceJarPath = m_inst->versionsPath().absoluteFilePath(version->id + "/" + version->id + ".jar");
 		QString localPath = version_id + "/" + version_id + ".jar";
-		QString strippedPath = version_id + "/" + version_id + "-stripped.jar";
 		auto metacache = MMC->metacache();
 		auto entry = metacache->resolveEntry("versions", localPath);
-		auto entryStripped = metacache->resolveEntry("versions", strippedPath);
-
 		QString fullJarPath = entry->getFullPath();
-		QString fullStrippedJarPath = entryStripped->getFullPath();
-		QFileInfo finfo(fullStrippedJarPath);
-		if (entry->md5sum != jarHashOnEntry || !finfo.exists())
+		//FIXME: remove need to convert to different objects here
+		QList<Mod> mods;
+		for (auto jarmod : version->jarMods)
+		{
+			QString filePath = m_inst->jarmodsPath().absoluteFilePath(jarmod->name);
+			mods.push_back(Mod(QFileInfo(filePath)));
+		}
+		if(!JarUtils::createModdedJar(sourceJarPath, finalJarPath, mods))
 		{
-			stripJar(fullJarPath, fullStrippedJarPath);
+			emitFailed(tr("Failed to create the custom Minecraft jar file."));
+			return;
 		}
 	}
 	if (version->traits.contains("legacyFML"))
@@ -324,87 +346,6 @@ void OneSixUpdate::jarlibFailed()
 		tr("Failed to download the following files:\n%1\n\nPlease try again.").arg(failed_all));
 }
 
-void OneSixUpdate::stripJar(QString origPath, QString newPath)
-{
-	QFileInfo runnableJar(newPath);
-	if (runnableJar.exists() && !QFile::remove(runnableJar.filePath()))
-	{
-		emitFailed("Failed to delete old minecraft.jar");
-		return;
-	}
-
-	// TaskStep(); // STEP 1
-	setStatus(tr("Creating stripped jar: Opening minecraft.jar ..."));
-
-	QuaZip zipOut(runnableJar.filePath());
-	if (!zipOut.open(QuaZip::mdCreate))
-	{
-		QFile::remove(runnableJar.filePath());
-		emitFailed("Failed to open the minecraft.jar for stripping");
-		return;
-	}
-	// Modify the jar
-	setStatus(tr("Creating stripped jar: Adding files..."));
-	if (!MergeZipFiles(&zipOut, origPath))
-	{
-		zipOut.close();
-		QFile::remove(runnableJar.filePath());
-		emitFailed("Failed to add " + origPath + " to the jar.");
-		return;
-	}
-}
-
-bool OneSixUpdate::MergeZipFiles(QuaZip *into, QString from)
-{
-	setStatus(tr("Installing mods: Adding ") + from + " ...");
-
-	QuaZip modZip(from);
-	modZip.open(QuaZip::mdUnzip);
-
-	QuaZipFile fileInsideMod(&modZip);
-	QuaZipFile zipOutFile(into);
-	for (bool more = modZip.goToFirstFile(); more; more = modZip.goToNextFile())
-	{
-		QString filename = modZip.getCurrentFileName();
-		if (filename.contains("META-INF"))
-		{
-			QLOG_INFO() << "Skipping META-INF " << filename << " from " << from;
-			continue;
-		}
-		QLOG_INFO() << "Adding file " << filename << " from " << from;
-
-		if (!fileInsideMod.open(QIODevice::ReadOnly))
-		{
-			QLOG_ERROR() << "Failed to open " << filename << " from " << from;
-			return false;
-		}
-		/*
-		QuaZipFileInfo old_info;
-		fileInsideMod.getFileInfo(&old_info);
-		*/
-		QuaZipNewInfo info_out(fileInsideMod.getActualFileName());
-		/*
-		info_out.externalAttr = old_info.externalAttr;
-		*/
-		if (!zipOutFile.open(QIODevice::WriteOnly, info_out))
-		{
-			QLOG_ERROR() << "Failed to open " << filename << " in the jar";
-			fileInsideMod.close();
-			return false;
-		}
-		if (!JlCompress::copyData(fileInsideMod, zipOutFile))
-		{
-			zipOutFile.close();
-			fileInsideMod.close();
-			QLOG_ERROR() << "Failed to copy data of " << filename << " into the jar";
-			return false;
-		}
-		zipOutFile.close();
-		fileInsideMod.close();
-	}
-	return true;
-}
-
 void OneSixUpdate::fmllibsStart()
 {
 	// Get the mod list
diff --git a/logic/OneSixUpdate.h b/logic/OneSixUpdate.h
index 2cad7408..5bbe86ba 100644
--- a/logic/OneSixUpdate.h
+++ b/logic/OneSixUpdate.h
@@ -53,8 +53,6 @@ slots:
 	void assetsFinished();
 	void assetsFailed();
 
-	void stripJar(QString origPath, QString newPath);
-	bool MergeZipFiles(QuaZip *into, QString from);
 private:
 	NetJobPtr jarlibDownloadJob;
 	NetJobPtr legacyDownloadJob;
@@ -63,7 +61,7 @@ private:
 	std::shared_ptr<MinecraftVersion> targetVersion;
 	/// the task that is spawned for version updates
 	std::shared_ptr<Task> versionUpdateTask;
-	
+
 	OneSixInstance *m_inst = nullptr;
 	QString jarHashOnEntry;
 	QList<FMLlib> fmlLibsToProcess;
diff --git a/logic/URNResolver.cpp b/logic/URNResolver.cpp
deleted file mode 100644
index b6bdcf41..00000000
--- a/logic/URNResolver.cpp
+++ /dev/null
@@ -1,98 +0,0 @@
-#include "URNResolver.h"
-#include <logger/QsLog.h>
-#include "MultiMC.h"
-#include "logic/forge/ForgeVersionList.h"
-#include "logic/forge/ForgeVersion.h"
-
-QString unescapeNSS(QString RawNSS)
-{
-	QString NSS;
-	NSS.reserve(RawNSS.size());
-	enum
-	{
-		Normal,
-		FirstHex,
-		SecondHex
-	} ParseState = Normal;
-
-	QByteArray translator("  ");
-
-	for (auto ch : RawNSS)
-	{
-		if(ParseState == Normal)
-		{
-			if(ch == '%')
-			{
-				ParseState = FirstHex;
-				continue;
-			}
-			else
-			{
-				NSS.append(ch);
-			}
-		}
-		if(ParseState == FirstHex)
-		{
-			translator[0] = ch.toLower().unicode();
-			ParseState = SecondHex;
-		}
-		else if(ParseState == SecondHex)
-		{
-			translator[1] = ch.toLower().unicode();
-			auto result = QByteArray::fromHex(translator);
-			if (result[0] == '\0')
-				return NSS;
-			NSS.append(result);
-			ParseState = Normal;
-		}
-	}
-	return NSS;
-}
-
-bool URNResolver::parse(const QString &URN, QString &NID, QString &NSS)
-{
-	QRegExp URNPattern(
-		"^urn:([a-z0-9][a-z0-9-]{0,31}):(([a-z0-9()+,\\-.:=@;$_!*']|%[0-9a-f]{2})+).*",
-		Qt::CaseInsensitive);
-	if (URNPattern.indexIn(URN) == -1)
-		return false;
-	auto captures = URNPattern.capturedTexts();
-	QString RawNID = captures[1];
-	QString RawNSS = captures[2];
-
-	NID = RawNID.toLower();
-	NSS = unescapeNSS(RawNSS);
-	return true;
-}
-
-URNResolver::URNResolver()
-{
-}
-
-QVariant URNResolver::resolve(QString URN)
-{
-	QString NID, NSS;
-	parse(URN, NID, NSS);
-
-	if(NID != "x-mmc")
-		return QVariant();
-	auto parts = NSS.split(":");
-	if(parts.size() < 1)
-		return QVariant();
-	unsigned int version = parts[0].toUInt();
-	switch(version)
-	{
-		case 1:
-			return resolveV1(parts.mid(1));
-		default:
-			return QVariant();
-	}
-}
-
-/**
- * TODO: implement.
- */
-QVariant URNResolver::resolveV1(QStringList parts)
-{
-	return QVariant();
-}
diff --git a/logic/URNResolver.h b/logic/URNResolver.h
deleted file mode 100644
index dfc7f5eb..00000000
--- a/logic/URNResolver.h
+++ /dev/null
@@ -1,18 +0,0 @@
-#pragma once
-#include <QString>
-#include <QMap>
-#include <memory>
-#include <QVariant>
-
-class URNResolver;
-typedef std::shared_ptr<URNResolver> URNResolverPtr;
-
-class URNResolver
-{
-public:
-	URNResolver();
-	QVariant resolve (QString URN);
-	static bool parse (const QString &URN, QString &NID, QString &NSS);
-private:
-	QVariant resolveV1 (QStringList parts);
-};
diff --git a/logic/minecraft/VersionFile.cpp b/logic/minecraft/VersionFile.cpp
index 311271fe..3e0648cc 100644
--- a/logic/minecraft/VersionFile.cpp
+++ b/logic/minecraft/VersionFile.cpp
@@ -43,6 +43,7 @@ VersionFilePtr VersionFile::fromJson(const QJsonDocument &doc, const QString &fi
 	}
 	if (!doc.isObject())
 	{
+		throw JSONValidationError(filename + " is not an object");
 	}
 
 	QJsonObject root = doc.object();