NOISSUE reorganize and document libraries

10 files changed, 1645 insertions, 0 deletions

diff --git a/api/logic/minecraft/forge/ForgeInstaller.cpp b/api/logic/minecraft/forge/ForgeInstaller.cpp
new file mode 100644
index 00000000..353328ab
--- /dev/null
+++ b/api/logic/minecraft/forge/ForgeInstaller.cpp
@@ -0,0 +1,458 @@
+/* Copyright 2013-2015 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 "ForgeInstaller.h"
+#include "ForgeVersionList.h"
+
+#include "minecraft/MinecraftProfile.h"
+#include "minecraft/GradleSpecifier.h"
+#include "net/HttpMetaCache.h"
+#include "tasks/Task.h"
+#include "minecraft/onesix/OneSixInstance.h"
+#include <minecraft/onesix/OneSixVersionFormat.h>
+#include "minecraft/VersionFilterData.h"
+#include "minecraft/MinecraftVersion.h"
+#include "Env.h"
+#include "Exception.h"
+#include <FileSystem.h>
+
+#include <quazip.h>
+#include <quazipfile.h>
+#include <QStringList>
+#include <QRegularExpression>
+#include <QRegularExpressionMatch>
+
+#include <QJsonDocument>
+#include <QJsonArray>
+#include <QSaveFile>
+#include <QCryptographicHash>
+
+ForgeInstaller::ForgeInstaller() : BaseInstaller()
+{
+}
+
+void ForgeInstaller::prepare(const QString &filename, const QString &universalUrl)
+{
+	VersionFilePtr newVersion;
+	m_universal_url = universalUrl;
+
+	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;
+
+	try
+	{
+		newVersion = OneSixVersionFormat::versionFileFromJson(QJsonDocument(versionInfoVal.toObject()), QString(), false);
+	}
+	catch(Exception &err)
+	{
+		qWarning() << "Forge: Fatal error while parsing version file:" << err.what();
+		return;
+	}
+
+	for(auto problem: newVersion->getProblems())
+	{
+		qWarning() << "Forge: Problem found: " << problem.getDescription();
+	}
+	if(newVersion->getProblemSeverity() == ProblemSeverity::PROBLEM_ERROR)
+	{
+		qWarning() << "Forge: Errors found while parsing version file";
+		return;
+	}
+
+	QJsonObject installObj = installVal.toObject();
+	QString libraryName = installObj.value("path").toString();
+	internalPath = installObj.value("filePath").toString();
+	m_forgeVersionString = installObj.value("version").toString().remove("Forge", Qt::CaseInsensitive).trimmed();
+
+	// where do we put the library? decode the mojang path
+	GradleSpecifier lib(libraryName);
+
+	auto cacheentry = ENV.metacache()->resolveEntry("libraries", lib.toPath());
+	finalPath = "libraries/" + lib.toPath();
+	if (!FS::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->setStale(false);
+		cacheentry->setMD5Sum(md5sum.result().toHex().constData());
+		ENV.metacache()->updateEntry(cacheentry);
+	}
+	file.close();
+
+	m_forge_json = newVersion;
+}
+
+bool ForgeInstaller::add(OneSixInstance *to)
+{
+	if (!BaseInstaller::add(to))
+	{
+		return false;
+	}
+
+	if (!m_forge_json)
+	{
+		return false;
+	}
+
+	// A blacklist
+	QSet<QString> blacklist{"authlib", "realms"};
+	QList<QString> xzlist{"org.scala-lang", "com.typesafe"};
+
+	// get the minecraft version from the instance
+	VersionFilePtr minecraft;
+	auto minecraftPatch = to->getMinecraftProfile()->versionPatch("net.minecraft");
+	if(minecraftPatch)
+	{
+		minecraft = std::dynamic_pointer_cast<VersionFile>(minecraftPatch);
+		if(!minecraft)
+		{
+			auto mcWrap = std::dynamic_pointer_cast<MinecraftVersion>(minecraftPatch);
+			if(mcWrap)
+			{
+				minecraft = mcWrap->getVersionFile();
+			}
+		}
+	}
+
+	// for each library in the version we are adding (except for the blacklisted)
+	QMutableListIterator<LibraryPtr> iter(m_forge_json->libraries);
+	while (iter.hasNext())
+	{
+		auto library = iter.next();
+		QString libName = library->artifactId();
+		QString libVersion = library->version();
+		QString rawName = library->rawName();
+
+		// ignore lwjgl libraries.
+		if (g_VersionFilterData.lwjglWhitelist.contains(library->artifactPrefix()))
+		{
+			iter.remove();
+			continue;
+		}
+		// ignore other blacklisted (realms, authlib)
+		if (blacklist.contains(libName))
+		{
+			iter.remove();
+			continue;
+		}
+		// if minecraft version was found, ignore everything that is already in the minecraft version
+		if(minecraft)
+		{
+			bool found = false;
+			for (auto & lib: minecraft->libraries)
+			{
+				if(library->artifactPrefix() == lib->artifactPrefix() && library->version() == lib->version())
+				{
+					found = true;
+					break;
+				}
+			}
+			if (found)
+				continue;
+		}
+
+		// if this is the actual forge lib, set an absolute url for the download
+		if (m_forge_version->type == ForgeVersion::Gradle)
+		{
+			if (libName == "forge")
+			{
+				library->setClassifier("universal");
+			}
+			else if (libName == "minecraftforge")
+			{
+				QString forgeCoord("net.minecraftforge:forge:%1:universal");
+				// using insane form of the MC version...
+				QString longVersion = m_forge_version->mcver + "-" + m_forge_version->jobbuildver;
+				GradleSpecifier spec(forgeCoord.arg(longVersion));
+				library->setRawName(spec);
+			}
+		}
+		else
+		{
+			if (libName.contains("minecraftforge"))
+			{
+				library->setAbsoluteUrl(m_universal_url);
+			}
+		}
+
+		// mark bad libraries based on the xzlist above
+		for (auto entry : xzlist)
+		{
+			qDebug() << "Testing " << rawName << " : " << entry;
+			if (rawName.startsWith(entry))
+			{
+				library->setHint("forge-pack-xz");
+				break;
+			}
+		}
+	}
+	QString &args = m_forge_json->minecraftArguments;
+	QStringList tweakers;
+	{
+		QRegularExpression expression("--tweakClass ([a-zA-Z0-9\\.]*)");
+		QRegularExpressionMatch match = expression.match(args);
+		while (match.hasMatch())
+		{
+			tweakers.append(match.captured(1));
+			args.remove(match.capturedStart(), match.capturedLength());
+			match = expression.match(args);
+		}
+		if(tweakers.size())
+		{
+			args.operator=(args.trimmed());
+			m_forge_json->addTweakers = tweakers;
+		}
+	}
+	if(minecraft && args == minecraft->minecraftArguments)
+	{
+		args.clear();
+	}
+
+	m_forge_json->name = "Forge";
+	m_forge_json->fileId = id();
+	m_forge_json->version = m_forgeVersionString;
+	m_forge_json->dependsOnMinecraftVersion = to->intendedVersionId();
+	m_forge_json->order = 5;
+
+	// reset some things we do not want to be passed along.
+	m_forge_json->m_releaseTime = QDateTime();
+	m_forge_json->m_updateTime = QDateTime();
+	m_forge_json->minimumLauncherVersion = -1;
+	m_forge_json->type.clear();
+	m_forge_json->minecraftArguments.clear();
+	m_forge_json->minecraftVersion.clear();
+
+	QSaveFile file(filename(to->instanceRoot()));
+	if (!file.open(QFile::WriteOnly))
+	{
+		qCritical() << "Error opening" << file.fileName()
+					 << "for reading:" << file.errorString();
+		return false;
+	}
+	file.write(OneSixVersionFormat::versionFileToJson(m_forge_json, true).toJson());
+	file.commit();
+
+	return true;
+}
+
+bool ForgeInstaller::addLegacy(OneSixInstance *to)
+{
+	if (!BaseInstaller::add(to))
+	{
+		return false;
+	}
+	auto entry = ENV.metacache()->resolveEntry("minecraftforge", m_forge_version->filename());
+	finalPath = FS::PathCombine(to->jarModsDir(), m_forge_version->filename());
+	if (!FS::ensureFilePathExists(finalPath))
+	{
+		return false;
+	}
+	if (!QFile::copy(entry->getFullPath(), finalPath))
+	{
+		return false;
+	}
+	QJsonObject obj;
+	obj.insert("order", 5);
+	{
+		QJsonArray jarmodsPlus;
+		{
+			QJsonObject libObj;
+			libObj.insert("name", m_forge_version->universal_filename);
+			jarmodsPlus.append(libObj);
+		}
+		obj.insert("+jarMods", jarmodsPlus);
+	}
+
+	obj.insert("name", QString("Forge"));
+	obj.insert("fileId", id());
+	obj.insert("version", m_forge_version->jobbuildver);
+	obj.insert("mcVersion", to->intendedVersionId());
+	if (g_VersionFilterData.fmlLibsMapping.contains(m_forge_version->mcver))
+	{
+		QJsonArray traitsPlus;
+		traitsPlus.append(QString("legacyFML"));
+		obj.insert("+traits", traitsPlus);
+	}
+	auto fullversion = to->getMinecraftProfile();
+	fullversion->remove("net.minecraftforge");
+
+	QFile file(filename(to->instanceRoot()));
+	if (!file.open(QFile::WriteOnly))
+	{
+		qCritical() << "Error opening" << file.fileName()
+					 << "for reading:" << file.errorString();
+		return false;
+	}
+	file.write(QJsonDocument(obj).toJson());
+	file.close();
+	return true;
+}
+
+class ForgeInstallTask : public Task
+{
+	Q_OBJECT
+public:
+	ForgeInstallTask(ForgeInstaller *installer, OneSixInstance *instance,
+					 BaseVersionPtr version, QObject *parent = 0)
+		: Task(parent), m_installer(installer), m_instance(instance), m_version(version)
+	{
+	}
+
+protected:
+	void executeTask() override
+	{
+		setStatus(tr("Installing Forge..."));
+		ForgeVersionPtr forgeVersion = std::dynamic_pointer_cast<ForgeVersion>(m_version);
+		if (!forgeVersion)
+		{
+			emitFailed(tr("Unknown error occured"));
+			return;
+		}
+		prepare(forgeVersion);
+	}
+	void prepare(ForgeVersionPtr forgeVersion)
+	{
+		auto entry = ENV.metacache()->resolveEntry("minecraftforge", forgeVersion->filename());
+		auto installFunction = [this, entry, forgeVersion]()
+		{
+			if (!install(entry, forgeVersion))
+			{
+				qCritical() << "Failure installing Forge";
+				emitFailed(tr("Failure to install Forge"));
+			}
+			else
+			{
+				reload();
+			}
+		};
+
+		/*
+		 * HACK IF the local non-stale file is too small, mark is as stale
+		 *
+		 * This fixes some problems with bad files acquired because of unhandled HTTP redirects
+		 * in old versions of MultiMC.
+		 */
+		if (!entry->isStale())
+		{
+			QFileInfo localFile(entry->getFullPath());
+			if (localFile.size() <= 0x4000)
+			{
+				entry->setStale(true);
+			}
+		}
+
+		if (entry->isStale())
+		{
+			NetJob *fjob = new NetJob("Forge download");
+			fjob->addNetAction(CacheDownload::make(forgeVersion->url(), entry));
+			connect(fjob, &NetJob::progress, this, &Task::setProgress);
+			connect(fjob, &NetJob::status, this, &Task::setStatus);
+			connect(fjob, &NetJob::failed, [this](QString reason)
+			{ emitFailed(tr("Failure to download Forge:\n%1").arg(reason)); });
+			connect(fjob, &NetJob::succeeded, installFunction);
+			fjob->start();
+		}
+		else
+		{
+			installFunction();
+		}
+	}
+	bool install(const std::shared_ptr<MetaEntry> &entry, const ForgeVersionPtr &forgeVersion)
+	{
+		if (forgeVersion->usesInstaller())
+		{
+			QString forgePath = entry->getFullPath();
+			m_installer->prepare(forgePath, forgeVersion->universal_url);
+			return m_installer->add(m_instance);
+		}
+		else
+			return m_installer->addLegacy(m_instance);
+	}
+	void reload()
+	{
+		try
+		{
+			m_instance->reloadProfile();
+			emitSucceeded();
+		}
+		catch (Exception &e)
+		{
+			emitFailed(e.cause());
+		}
+		catch (...)
+		{
+			emitFailed(tr("Failed to load the version description file for reasons unknown."));
+		}
+	}
+
+private:
+	ForgeInstaller *m_installer;
+	OneSixInstance *m_instance;
+	BaseVersionPtr m_version;
+};
+
+Task *ForgeInstaller::createInstallTask(OneSixInstance *instance,
+													BaseVersionPtr version, QObject *parent)
+{
+	if (!version)
+	{
+		return nullptr;
+	}
+	m_forge_version = std::dynamic_pointer_cast<ForgeVersion>(version);
+	return new ForgeInstallTask(this, instance, version, parent);
+}
+
+#include "ForgeInstaller.moc"
diff --git a/api/logic/minecraft/forge/ForgeInstaller.h b/api/logic/minecraft/forge/ForgeInstaller.h
new file mode 100644
index 00000000..499a6fb3
--- /dev/null
+++ b/api/logic/minecraft/forge/ForgeInstaller.h
@@ -0,0 +1,52 @@
+/* Copyright 2013-2015 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 "BaseInstaller.h"
+
+#include <QString>
+#include <memory>
+
+#include "multimc_logic_export.h"
+
+class VersionFile;
+class ForgeInstallTask;
+struct ForgeVersion;
+
+class MULTIMC_LOGIC_EXPORT ForgeInstaller : public BaseInstaller
+{
+	friend class ForgeInstallTask;
+public:
+	ForgeInstaller();
+	virtual ~ForgeInstaller(){}
+	virtual Task *createInstallTask(OneSixInstance *instance, BaseVersionPtr version, QObject *parent) override;
+	virtual QString id() const override { return "net.minecraftforge"; }
+
+protected:
+	void prepare(const QString &filename, const QString &universalUrl);
+	bool add(OneSixInstance *to) override;
+	bool addLegacy(OneSixInstance *to);
+
+private:
+	// the parsed version json, read from the installer
+	std::shared_ptr<VersionFile> m_forge_json;
+	// the actual forge version
+	std::shared_ptr<ForgeVersion> m_forge_version;
+	QString internalPath;
+	QString finalPath;
+	QString m_forgeVersionString;
+	QString m_universal_url;
+};
diff --git a/api/logic/minecraft/forge/ForgeVersion.cpp b/api/logic/minecraft/forge/ForgeVersion.cpp
new file mode 100644
index 00000000..b859a28c
--- /dev/null
+++ b/api/logic/minecraft/forge/ForgeVersion.cpp
@@ -0,0 +1,55 @@
+#include "ForgeVersion.h"
+#include "minecraft/VersionFilterData.h"
+#include <QObject>
+
+QString ForgeVersion::name()
+{
+	return "Forge " + jobbuildver;
+}
+
+QString ForgeVersion::descriptor()
+{
+	return universal_filename;
+}
+
+QString ForgeVersion::typeString() const
+{
+	if (is_recommended)
+		return QObject::tr("Recommended");
+	return QString();
+}
+
+bool ForgeVersion::operator<(BaseVersion &a)
+{
+	ForgeVersion *pa = dynamic_cast<ForgeVersion *>(&a);
+	if (!pa)
+		return true;
+	return m_buildnr < pa->m_buildnr;
+}
+
+bool ForgeVersion::operator>(BaseVersion &a)
+{
+	ForgeVersion *pa = dynamic_cast<ForgeVersion *>(&a);
+	if (!pa)
+		return false;
+	return m_buildnr > pa->m_buildnr;
+}
+
+bool ForgeVersion::usesInstaller()
+{
+	if(installer_url.isEmpty())
+		return false;
+	if(g_VersionFilterData.forgeInstallerBlacklist.contains(mcver))
+		return false;
+	return true;
+}
+
+QString ForgeVersion::filename()
+{
+	return usesInstaller() ? installer_filename : universal_filename;
+}
+
+QString ForgeVersion::url()
+{
+	return usesInstaller() ? installer_url : universal_url;
+}
diff --git a/api/logic/minecraft/forge/ForgeVersion.h b/api/logic/minecraft/forge/ForgeVersion.h
new file mode 100644
index 00000000..e77d32f1
--- /dev/null
+++ b/api/logic/minecraft/forge/ForgeVersion.h
@@ -0,0 +1,42 @@
+#pragma once
+#include <QString>
+#include <memory>
+#include "BaseVersion.h"
+
+struct ForgeVersion;
+typedef std::shared_ptr<ForgeVersion> ForgeVersionPtr;
+
+struct ForgeVersion : public BaseVersion
+{
+	virtual QString descriptor() override;
+	virtual QString name() override;
+	virtual QString typeString() const override;
+	virtual bool operator<(BaseVersion &a) override;
+	virtual bool operator>(BaseVersion &a) override;
+
+	QString filename();
+	QString url();
+	
+	enum
+	{
+		Invalid,
+		Legacy,
+		Gradle
+	} type = Invalid;
+	
+	bool usesInstaller();
+
+	int m_buildnr = 0;
+	QString branch;
+	QString universal_url;
+	QString changelog_url;
+	QString installer_url;
+	QString jobbuildver;
+	QString mcver;
+	QString mcver_sane;
+	QString universal_filename;
+	QString installer_filename;
+	bool is_recommended = false;
+};
+
+Q_DECLARE_METATYPE(ForgeVersionPtr)
diff --git a/api/logic/minecraft/forge/ForgeVersionList.cpp b/api/logic/minecraft/forge/ForgeVersionList.cpp
new file mode 100644
index 00000000..de185e5f
--- /dev/null
+++ b/api/logic/minecraft/forge/ForgeVersionList.cpp
@@ -0,0 +1,450 @@
+/* Copyright 2013-2015 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 "ForgeVersionList.h"
+#include "ForgeVersion.h"
+
+#include "net/NetJob.h"
+#include "net/URLConstants.h"
+#include "Env.h"
+
+#include <QtNetwork>
+#include <QtXml>
+#include <QRegExp>
+
+#include <QDebug>
+
+ForgeVersionList::ForgeVersionList(QObject *parent) : BaseVersionList(parent)
+{
+}
+
+Task *ForgeVersionList::getLoadTask()
+{
+	return new ForgeListLoadTask(this);
+}
+
+bool ForgeVersionList::isLoaded()
+{
+	return m_loaded;
+}
+
+const BaseVersionPtr ForgeVersionList::at(int i) const
+{
+	return m_vlist.at(i);
+}
+
+int ForgeVersionList::count() const
+{
+	return m_vlist.count();
+}
+
+int ForgeVersionList::columnCount(const QModelIndex &parent) const
+{
+	return 1;
+}
+
+QVariant ForgeVersionList::data(const QModelIndex &index, int role) const
+{
+	if (!index.isValid())
+		return QVariant();
+
+	if (index.row() > count())
+		return QVariant();
+
+	auto version = std::dynamic_pointer_cast<ForgeVersion>(m_vlist[index.row()]);
+	switch (role)
+	{
+	case VersionPointerRole:
+		return qVariantFromValue(m_vlist[index.row()]);
+
+	case VersionRole:
+		return version->name();
+
+	case VersionIdRole:
+		return version->descriptor();
+
+	case ParentGameVersionRole:
+		return version->mcver_sane;
+
+	case RecommendedRole:
+		return version->is_recommended;
+
+	case BranchRole:
+		return version->branch;
+
+	default:
+		return QVariant();
+	}
+}
+
+BaseVersionList::RoleList ForgeVersionList::providesRoles() const
+{
+	return {VersionPointerRole, VersionRole, VersionIdRole, ParentGameVersionRole, RecommendedRole, BranchRole};
+}
+
+BaseVersionPtr ForgeVersionList::getLatestStable() const
+{
+	return BaseVersionPtr();
+}
+
+void ForgeVersionList::updateListData(QList<BaseVersionPtr> versions)
+{
+	beginResetModel();
+	m_vlist = versions;
+	m_loaded = true;
+	endResetModel();
+	// NOW SORT!!
+	// sort();
+}
+
+void ForgeVersionList::sortVersions()
+{
+	// NO-OP for now
+}
+
+ForgeListLoadTask::ForgeListLoadTask(ForgeVersionList *vlist) : Task()
+{
+	m_list = vlist;
+}
+
+void ForgeListLoadTask::executeTask()
+{
+	setStatus(tr("Fetching Forge version lists..."));
+	auto job = new NetJob("Version index");
+	// we do not care if the version is stale or not.
+	auto forgeListEntry = ENV.metacache()->resolveEntry("minecraftforge", "list.json");
+	auto gradleForgeListEntry = ENV.metacache()->resolveEntry("minecraftforge", "json");
+
+	// verify by poking the server.
+	forgeListEntry->setStale(true);
+	gradleForgeListEntry->setStale(true);
+
+	job->addNetAction(listDownload = CacheDownload::make(QUrl(URLConstants::FORGE_LEGACY_URL),
+														 forgeListEntry));
+	job->addNetAction(gradleListDownload = CacheDownload::make(
+						  QUrl(URLConstants::FORGE_GRADLE_URL), gradleForgeListEntry));
+
+	connect(listDownload.get(), SIGNAL(failed(int)), SLOT(listFailed()));
+	connect(gradleListDownload.get(), SIGNAL(failed(int)), SLOT(gradleListFailed()));
+
+	listJob.reset(job);
+	connect(listJob.get(), SIGNAL(succeeded()), SLOT(listDownloaded()));
+	connect(listJob.get(), SIGNAL(progress(qint64, qint64)), SIGNAL(progress(qint64, qint64)));
+	listJob->start();
+}
+
+bool ForgeListLoadTask::abort()
+{
+	return listJob->abort();
+}
+
+bool ForgeListLoadTask::parseForgeList(QList<BaseVersionPtr> &out)
+{
+	QByteArray data;
+	{
+		auto dlJob = listDownload;
+		auto filename = std::dynamic_pointer_cast<CacheDownload>(dlJob)->getTargetFilepath();
+		QFile listFile(filename);
+		if (!listFile.open(QIODevice::ReadOnly))
+		{
+			return false;
+		}
+		data = listFile.readAll();
+		dlJob.reset();
+	}
+
+	QJsonParseError jsonError;
+	QJsonDocument jsonDoc = QJsonDocument::fromJson(data, &jsonError);
+
+	if (jsonError.error != QJsonParseError::NoError)
+	{
+		emitFailed("Error parsing version list JSON:" + jsonError.errorString());
+		return false;
+	}
+
+	if (!jsonDoc.isObject())
+	{
+		emitFailed("Error parsing version list JSON: JSON root is not an object");
+		return false;
+	}
+
+	QJsonObject root = jsonDoc.object();
+
+	// Now, get the array of versions.
+	if (!root.value("builds").isArray())
+	{
+		emitFailed(
+			"Error parsing version list JSON: version list object is missing 'builds' array");
+		return false;
+	}
+	QJsonArray builds = root.value("builds").toArray();
+
+	for (int i = 0; i < builds.count(); i++)
+	{
+		// Load the version info.
+		if (!builds[i].isObject())
+		{
+			// FIXME: log this somewhere
+			continue;
+		}
+		QJsonObject obj = builds[i].toObject();
+		int build_nr = obj.value("build").toDouble(0);
+		if (!build_nr)
+			continue;
+		QJsonArray files = obj.value("files").toArray();
+		QString url, jobbuildver, mcver, buildtype, universal_filename;
+		QString changelog_url, installer_url;
+		QString installer_filename;
+		bool valid = false;
+		for (int j = 0; j < files.count(); j++)
+		{
+			if (!files[j].isObject())
+			{
+				continue;
+			}
+			QJsonObject file = files[j].toObject();
+			buildtype = file.value("buildtype").toString();
+			if ((buildtype == "client" || buildtype == "universal") && !valid)
+			{
+				mcver = file.value("mcver").toString();
+				url = file.value("url").toString();
+				jobbuildver = file.value("jobbuildver").toString();
+				int lastSlash = url.lastIndexOf('/');
+				universal_filename = url.mid(lastSlash + 1);
+				valid = true;
+			}
+			else if (buildtype == "changelog")
+			{
+				QString ext = file.value("ext").toString();
+				if (ext.isEmpty())
+				{
+					continue;
+				}
+				changelog_url = file.value("url").toString();
+			}
+			else if (buildtype == "installer")
+			{
+				installer_url = file.value("url").toString();
+				int lastSlash = installer_url.lastIndexOf('/');
+				installer_filename = installer_url.mid(lastSlash + 1);
+			}
+		}
+		if (valid)
+		{
+			// Now, we construct the version object and add it to the list.
+			std::shared_ptr<ForgeVersion> fVersion(new ForgeVersion());
+			fVersion->universal_url = url;
+			fVersion->changelog_url = changelog_url;
+			fVersion->installer_url = installer_url;
+			fVersion->jobbuildver = jobbuildver;
+			fVersion->mcver = fVersion->mcver_sane = mcver;
+			fVersion->installer_filename = installer_filename;
+			fVersion->universal_filename = universal_filename;
+			fVersion->m_buildnr = build_nr;
+			fVersion->type = ForgeVersion::Legacy;
+			out.append(fVersion);
+		}
+	}
+
+	return true;
+}
+
+bool ForgeListLoadTask::parseForgeGradleList(QList<BaseVersionPtr> &out)
+{
+	QMap<int, std::shared_ptr<ForgeVersion>> lookup;
+	QByteArray data;
+	{
+		auto dlJob = gradleListDownload;
+		auto filename = std::dynamic_pointer_cast<CacheDownload>(dlJob)->getTargetFilepath();
+		QFile listFile(filename);
+		if (!listFile.open(QIODevice::ReadOnly))
+		{
+			return false;
+		}
+		data = listFile.readAll();
+		dlJob.reset();
+	}
+
+	QJsonParseError jsonError;
+	QJsonDocument jsonDoc = QJsonDocument::fromJson(data, &jsonError);
+
+	if (jsonError.error != QJsonParseError::NoError)
+	{
+		emitFailed("Error parsing gradle version list JSON:" + jsonError.errorString());
+		return false;
+	}
+
+	if (!jsonDoc.isObject())
+	{
+		emitFailed("Error parsing gradle version list JSON: JSON root is not an object");
+		return false;
+	}
+
+	QJsonObject root = jsonDoc.object();
+
+	// we probably could hard code these, but it might still be worth doing it this way
+	const QString webpath = root.value("webpath").toString();
+	const QString artifact = root.value("artifact").toString();
+
+	QJsonObject numbers = root.value("number").toObject();
+	for (auto it = numbers.begin(); it != numbers.end(); ++it)
+	{
+		QJsonObject number = it.value().toObject();
+		std::shared_ptr<ForgeVersion> fVersion(new ForgeVersion());
+		fVersion->m_buildnr = number.value("build").toDouble();
+		if(fVersion->m_buildnr >= 953 && fVersion->m_buildnr <= 965)
+		{
+			qDebug() << fVersion->m_buildnr;
+		}
+		fVersion->jobbuildver = number.value("version").toString();
+		fVersion->branch = number.value("branch").toString("");
+		fVersion->mcver = number.value("mcversion").toString();
+		fVersion->universal_filename = "";
+		fVersion->installer_filename = "";
+		// HACK: here, we fix the minecraft version used by forge.
+		// HACK: this will inevitably break (later)
+		// FIXME: replace with a dictionary
+		fVersion->mcver_sane = fVersion->mcver;
+		fVersion->mcver_sane.replace("_pre", "-pre");
+
+		QString universal_filename, installer_filename;
+		QJsonArray files = number.value("files").toArray();
+		for (auto fIt = files.begin(); fIt != files.end(); ++fIt)
+		{
+			// TODO with gradle we also get checksums, use them
+			QJsonArray file = (*fIt).toArray();
+			if (file.size() < 3)
+			{
+				continue;
+			}
+
+			QString extension = file.at(0).toString();
+			QString part = file.at(1).toString();
+			QString checksum = file.at(2).toString();
+
+			// insane form of mcver is used here
+			QString longVersion = fVersion->mcver + "-" + fVersion->jobbuildver;
+			if (!fVersion->branch.isEmpty())
+			{
+				longVersion = longVersion + "-" + fVersion->branch;
+			}
+			QString filename = artifact + "-" + longVersion + "-" + part + "." + extension;
+
+			QString url = QString("%1/%2/%3")
+							  .arg(webpath)
+							  .arg(longVersion)
+							  .arg(filename);
+
+			if (part == "installer")
+			{
+				fVersion->installer_url = url;
+				installer_filename = filename;
+			}
+			else if (part == "universal")
+			{
+				fVersion->universal_url = url;
+				universal_filename = filename;
+			}
+			else if (part == "changelog")
+			{
+				fVersion->changelog_url = url;
+			}
+		}
+		if (fVersion->installer_url.isEmpty() && fVersion->universal_url.isEmpty())
+		{
+			continue;
+		}
+		fVersion->universal_filename = universal_filename;
+		fVersion->installer_filename = installer_filename;
+		fVersion->type = ForgeVersion::Gradle;
+		out.append(fVersion);
+		lookup[fVersion->m_buildnr] = fVersion;
+	}
+	QJsonObject promos = root.value("promos").toObject();
+	for (auto it = promos.begin(); it != promos.end(); ++it)
+	{
+		QString key = it.key();
+		int build = it.value().toInt();
+		QRegularExpression regexp("^(?<mcversion>[0-9]+(.[0-9]+)*)-(?<label>[a-z]+)$");
+		auto match = regexp.match(key);
+		if(!match.hasMatch())
+		{
+			qDebug() << key << "doesn't match." << "build" << build;
+			continue;
+		}
+
+		QString label = match.captured("label");
+		if(label != "recommended")
+		{
+			continue;
+		}
+		QString mcversion = match.captured("mcversion");
+		qDebug() << "Forge build" << build << "is the" << label << "for Minecraft" << mcversion << QString("<%1>").arg(key);
+		lookup[build]->is_recommended = true;
+	}
+	return true;
+}
+
+void ForgeListLoadTask::listDownloaded()
+{
+	QList<BaseVersionPtr> list;
+	bool ret = true;
+	if (!parseForgeList(list))
+	{
+		ret = false;
+	}
+	if (!parseForgeGradleList(list))
+	{
+		ret = false;
+	}
+
+	if (!ret)
+	{
+		return;
+	}
+	std::sort(list.begin(), list.end(), [](const BaseVersionPtr & l, const BaseVersionPtr & r)
+	{ return (*l > *r); });
+
+	m_list->updateListData(list);
+
+	emitSucceeded();
+	return;
+}
+
+void ForgeListLoadTask::listFailed()
+{
+	auto &reply = listDownload->m_reply;
+	if (reply)
+	{
+		qCritical() << "Getting forge version list failed: " << reply->errorString();
+	}
+	else
+	{
+		qCritical() << "Getting forge version list failed for reasons unknown.";
+	}
+}
+
+void ForgeListLoadTask::gradleListFailed()
+{
+	auto &reply = gradleListDownload->m_reply;
+	if (reply)
+	{
+		qCritical() << "Getting forge version list failed: " << reply->errorString();
+	}
+	else
+	{
+		qCritical() << "Getting forge version list failed for reasons unknown.";
+	}
+}
diff --git a/api/logic/minecraft/forge/ForgeVersionList.h b/api/logic/minecraft/forge/ForgeVersionList.h
new file mode 100644
index 00000000..62c08b2a
--- /dev/null
+++ b/api/logic/minecraft/forge/ForgeVersionList.h
@@ -0,0 +1,90 @@
+/* Copyright 2013-2015 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 "ForgeVersion.h"
+
+#include <QObject>
+#include <QAbstractListModel>
+#include <QUrl>
+#include <QNetworkReply>
+
+#include "BaseVersionList.h"
+#include "tasks/Task.h"
+#include "net/NetJob.h"
+
+#include "multimc_logic_export.h"
+
+class MULTIMC_LOGIC_EXPORT ForgeVersionList : public BaseVersionList
+{
+	Q_OBJECT
+public:
+	friend class ForgeListLoadTask;
+
+	explicit ForgeVersionList(QObject *parent = 0);
+
+	virtual Task *getLoadTask() override;
+	virtual bool isLoaded() override;
+	virtual const BaseVersionPtr at(int i) const override;
+	virtual int count() const override;
+	virtual void sortVersions() override;
+
+	virtual BaseVersionPtr getLatestStable() const override;
+
+	ForgeVersionPtr findVersionByVersionNr(QString version);
+
+	virtual QVariant data(const QModelIndex &index, int role) const override;
+	virtual RoleList providesRoles() const override;
+
+	virtual int columnCount(const QModelIndex &parent) const override;
+
+protected:
+	QList<BaseVersionPtr> m_vlist;
+
+	bool m_loaded = false;
+
+protected
+slots:
+	virtual void updateListData(QList<BaseVersionPtr> versions) override;
+};
+
+class ForgeListLoadTask : public Task
+{
+	Q_OBJECT
+
+public:
+	explicit ForgeListLoadTask(ForgeVersionList *vlist);
+
+	virtual void executeTask();
+	virtual bool abort();
+
+protected
+slots:
+	void listDownloaded();
+	void listFailed();
+	void gradleListFailed();
+
+protected:
+	NetJobPtr listJob;
+	ForgeVersionList *m_list;
+
+	CacheDownloadPtr listDownload;
+	CacheDownloadPtr gradleListDownload;
+
+private:
+	bool parseForgeList(QList<BaseVersionPtr> &out);
+	bool parseForgeGradleList(QList<BaseVersionPtr> &out);
+};
diff --git a/api/logic/minecraft/forge/ForgeXzDownload.cpp b/api/logic/minecraft/forge/ForgeXzDownload.cpp
new file mode 100644
index 00000000..adf96552
--- /dev/null
+++ b/api/logic/minecraft/forge/ForgeXzDownload.cpp
@@ -0,0 +1,358 @@
+/* Copyright 2013-2015 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 "Env.h"
+#include "ForgeXzDownload.h"
+#include <FileSystem.h>
+
+#include <QCryptographicHash>
+#include <QFileInfo>
+#include <QDateTime>
+#include <QDir>
+#include <QDebug>
+
+ForgeXzDownload::ForgeXzDownload(QString relative_path, MetaEntryPtr entry) : NetAction()
+{
+	m_entry = entry;
+	m_target_path = entry->getFullPath();
+	m_pack200_xz_file.setFileTemplate("./dl_temp.XXXXXX");
+	m_status = Job_NotStarted;
+	m_url_path = relative_path;
+	m_url = "http://files.minecraftforge.net/maven/" + m_url_path + ".pack.xz";
+}
+
+void ForgeXzDownload::start()
+{
+	m_status = Job_InProgress;
+	if (!m_entry->isStale())
+	{
+		m_status = Job_Finished;
+		emit succeeded(m_index_within_job);
+		return;
+	}
+	// can we actually create the real, final file?
+	if (!FS::ensureFilePathExists(m_target_path))
+	{
+		m_status = Job_Failed;
+		emit failed(m_index_within_job);
+		return;
+	}
+
+	qDebug() << "Downloading " << m_url.toString();
+	QNetworkRequest request(m_url);
+	request.setRawHeader(QString("If-None-Match").toLatin1(), m_entry->getETag().toLatin1());
+	request.setHeader(QNetworkRequest::UserAgentHeader, "MultiMC/5.0 (Cached)");
+
+	auto worker = ENV.qnam();
+	QNetworkReply *rep = worker->get(request);
+
+	m_reply.reset(rep);
+	connect(rep, SIGNAL(downloadProgress(qint64, qint64)),
+			SLOT(downloadProgress(qint64, qint64)));
+	connect(rep, SIGNAL(finished()), SLOT(downloadFinished()));
+	connect(rep, SIGNAL(error(QNetworkReply::NetworkError)),
+			SLOT(downloadError(QNetworkReply::NetworkError)));
+	connect(rep, SIGNAL(readyRead()), SLOT(downloadReadyRead()));
+}
+
+void ForgeXzDownload::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
+{
+	m_total_progress = bytesTotal;
+	m_progress = bytesReceived;
+	emit netActionProgress(m_index_within_job, bytesReceived, bytesTotal);
+}
+
+void ForgeXzDownload::downloadError(QNetworkReply::NetworkError error)
+{
+	// error happened during download.
+	// TODO: log the reason why
+	m_status = Job_Failed;
+}
+
+void ForgeXzDownload::failAndTryNextMirror()
+{
+	m_status = Job_Failed;
+	emit failed(m_index_within_job);
+}
+
+void ForgeXzDownload::downloadFinished()
+{
+	// if the download succeeded
+	if (m_status != Job_Failed)
+	{
+		// nothing went wrong...
+		m_status = Job_Finished;
+		if (m_pack200_xz_file.isOpen())
+		{
+			// we actually downloaded something! process and isntall it
+			decompressAndInstall();
+			return;
+		}
+		else
+		{
+			// something bad happened -- on the local machine!
+			m_status = Job_Failed;
+			m_pack200_xz_file.remove();
+			m_reply.reset();
+			emit failed(m_index_within_job);
+			return;
+		}
+	}
+	// else the download failed
+	else
+	{
+		m_status = Job_Failed;
+		m_pack200_xz_file.close();
+		m_pack200_xz_file.remove();
+		m_reply.reset();
+		failAndTryNextMirror();
+		return;
+	}
+}
+
+void ForgeXzDownload::downloadReadyRead()
+{
+
+	if (!m_pack200_xz_file.isOpen())
+	{
+		if (!m_pack200_xz_file.open())
+		{
+			/*
+			* Can't open the file... the job failed
+			*/
+			m_reply->abort();
+			emit failed(m_index_within_job);
+			return;
+		}
+	}
+	m_pack200_xz_file.write(m_reply->readAll());
+}
+
+#include "xz.h"
+#include "unpack200.h"
+#include <stdexcept>
+#include <unistd.h>
+
+const size_t buffer_size = 8196;
+
+void ForgeXzDownload::decompressAndInstall()
+{
+	// rewind the downloaded temp file
+	m_pack200_xz_file.seek(0);
+	// de-xz'd file
+	QTemporaryFile pack200_file("./dl_temp.XXXXXX");
+	pack200_file.open();
+
+	bool xz_success = false;
+	// first, de-xz
+	{
+		uint8_t in[buffer_size];
+		uint8_t out[buffer_size];
+		struct xz_buf b;
+		struct xz_dec *s;
+		enum xz_ret ret;
+		xz_crc32_init();
+		xz_crc64_init();
+		s = xz_dec_init(XZ_DYNALLOC, 1 << 26);
+		if (s == nullptr)
+		{
+			xz_dec_end(s);
+			failAndTryNextMirror();
+			return;
+		}
+		b.in = in;
+		b.in_pos = 0;
+		b.in_size = 0;
+		b.out = out;
+		b.out_pos = 0;
+		b.out_size = buffer_size;
+		while (!xz_success)
+		{
+			if (b.in_pos == b.in_size)
+			{
+				b.in_size = m_pack200_xz_file.read((char *)in, sizeof(in));
+				b.in_pos = 0;
+			}
+
+			ret = xz_dec_run(s, &b);
+
+			if (b.out_pos == sizeof(out))
+			{
+				if (pack200_file.write((char *)out, b.out_pos) != b.out_pos)
+				{
+					// msg = "Write error\n";
+					xz_dec_end(s);
+					failAndTryNextMirror();
+					return;
+				}
+
+				b.out_pos = 0;
+			}
+
+			if (ret == XZ_OK)
+				continue;
+
+			if (ret == XZ_UNSUPPORTED_CHECK)
+			{
+				// unsupported check. this is OK, but we should log this
+				continue;
+			}
+
+			if (pack200_file.write((char *)out, b.out_pos) != b.out_pos)
+			{
+				// write error
+				pack200_file.close();
+				xz_dec_end(s);
+				return;
+			}
+
+			switch (ret)
+			{
+			case XZ_STREAM_END:
+				xz_dec_end(s);
+				xz_success = true;
+				break;
+
+			case XZ_MEM_ERROR:
+				qCritical() << "Memory allocation failed\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+
+			case XZ_MEMLIMIT_ERROR:
+				qCritical() << "Memory usage limit reached\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+
+			case XZ_FORMAT_ERROR:
+				qCritical() << "Not a .xz file\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+
+			case XZ_OPTIONS_ERROR:
+				qCritical() << "Unsupported options in the .xz headers\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+
+			case XZ_DATA_ERROR:
+			case XZ_BUF_ERROR:
+				qCritical() << "File is corrupt\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+
+			default:
+				qCritical() << "Bug!\n";
+				xz_dec_end(s);
+				failAndTryNextMirror();
+				return;
+			}
+		}
+	}
+	m_pack200_xz_file.remove();
+
+	// revert pack200
+	pack200_file.seek(0);
+	int handle_in = pack200_file.handle();
+	// FIXME: dispose of file handles, pointers and the like. Ideally wrap in objects.
+	if(handle_in == -1)
+	{
+		qCritical() << "Error reopening " << pack200_file.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	int handle_in_dup = dup (handle_in);
+	if(handle_in_dup == -1)
+	{
+		qCritical() << "Error reopening " << pack200_file.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	FILE *file_in = fdopen (handle_in_dup, "rb");
+	if(!file_in)
+	{
+		qCritical() << "Error reopening " << pack200_file.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	QFile qfile_out(m_target_path);
+	if(!qfile_out.open(QIODevice::WriteOnly))
+	{
+		qCritical() << "Error opening " << qfile_out.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	int handle_out = qfile_out.handle();
+	if(handle_out == -1)
+	{
+		qCritical() << "Error opening " << qfile_out.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	int handle_out_dup = dup (handle_out);
+	if(handle_out_dup == -1)
+	{
+		qCritical() << "Error reopening " << qfile_out.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	FILE *file_out = fdopen (handle_out_dup, "wb");
+	if(!file_out)
+	{
+		qCritical() << "Error opening " << qfile_out.fileName();
+		failAndTryNextMirror();
+		return;
+	}
+	try
+	{
+		// NOTE: this takes ownership of both FILE pointers. That's why we duplicate them above.
+		unpack_200(file_in, file_out);
+	}
+	catch (std::runtime_error &err)
+	{
+		m_status = Job_Failed;
+		qCritical() << "Error unpacking " << pack200_file.fileName() << " : " << err.what();
+		QFile f(m_target_path);
+		if (f.exists())
+			f.remove();
+		failAndTryNextMirror();
+		return;
+	}
+	pack200_file.remove();
+
+	QFile jar_file(m_target_path);
+
+	if (!jar_file.open(QIODevice::ReadOnly))
+	{
+		jar_file.remove();
+		failAndTryNextMirror();
+		return;
+	}
+	auto hash = QCryptographicHash::hash(jar_file.readAll(), QCryptographicHash::Md5);
+	m_entry->setMD5Sum(hash.toHex().constData());
+	jar_file.close();
+
+	QFileInfo output_file_info(m_target_path);
+	m_entry->setETag(m_reply->rawHeader("ETag").constData());
+	m_entry->setLocalChangedTimestamp(output_file_info.lastModified().toUTC().toMSecsSinceEpoch());
+	m_entry->setStale(false);
+	ENV.metacache()->updateEntry(m_entry);
+
+	m_reply.reset();
+	emit succeeded(m_index_within_job);
+}
diff --git a/api/logic/minecraft/forge/ForgeXzDownload.h b/api/logic/minecraft/forge/ForgeXzDownload.h
new file mode 100644
index 00000000..67524405
--- /dev/null
+++ b/api/logic/minecraft/forge/ForgeXzDownload.h
@@ -0,0 +1,59 @@
+/* Copyright 2013-2015 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 "net/NetAction.h"
+#include "net/HttpMetaCache.h"
+#include <QFile>
+#include <QTemporaryFile>
+
+typedef std::shared_ptr<class ForgeXzDownload> ForgeXzDownloadPtr;
+
+class ForgeXzDownload : public NetAction
+{
+	Q_OBJECT
+public:
+	MetaEntryPtr m_entry;
+	/// if saving to file, use the one specified in this string
+	QString m_target_path;
+	/// this is the output file, if any
+	QTemporaryFile m_pack200_xz_file;
+	/// path relative to the mirror base
+	QString m_url_path;
+
+public:
+	explicit ForgeXzDownload(QString relative_path, MetaEntryPtr entry);
+	static ForgeXzDownloadPtr make(QString relative_path, MetaEntryPtr entry)
+	{
+		return ForgeXzDownloadPtr(new ForgeXzDownload(relative_path, entry));
+	}
+	virtual ~ForgeXzDownload(){};
+
+protected
+slots:
+	virtual void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);
+	virtual void downloadError(QNetworkReply::NetworkError error);
+	virtual void downloadFinished();
+	virtual void downloadReadyRead();
+
+public
+slots:
+	virtual void start();
+
+private:
+	void decompressAndInstall();
+	void failAndTryNextMirror();
+};
diff --git a/api/logic/minecraft/forge/LegacyForge.cpp b/api/logic/minecraft/forge/LegacyForge.cpp
new file mode 100644
index 00000000..aa2c8063
--- /dev/null
+++ b/api/logic/minecraft/forge/LegacyForge.cpp
@@ -0,0 +1,56 @@
+/* Copyright 2013-2015 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 "LegacyForge.h"
+
+MinecraftForge::MinecraftForge(const QString &file) : Mod(file)
+{
+}
+
+bool MinecraftForge::FixVersionIfNeeded(QString newVersion)
+{/*
+	wxString reportedVersion = GetModVersion();
+	if(reportedVersion == "..." || reportedVersion.empty())
+	{
+		std::auto_ptr<wxFFileInputStream> in(new wxFFileInputStream("forge.zip"));
+		wxTempFileOutputStream out("forge.zip");
+		wxTextOutputStream textout(out);
+		wxZipInputStream inzip(*in);
+		wxZipOutputStream outzip(out);
+		std::auto_ptr<wxZipEntry> entry;
+		// preserve metadata
+		outzip.CopyArchiveMetaData(inzip);
+		// copy all entries
+		while (entry.reset(inzip.GetNextEntry()), entry.get() != NULL)
+			if (!outzip.CopyEntry(entry.release(), inzip))
+				return false;
+		// release last entry
+		in.reset();
+		outzip.PutNextEntry("forgeversion.properties");
+
+		wxStringTokenizer tokenizer(newVersion,".");
+		wxString verFile;
+		verFile << wxString("forge.major.number=") << tokenizer.GetNextToken() << "\n";
+		verFile << wxString("forge.minor.number=") << tokenizer.GetNextToken() << "\n";
+		verFile << wxString("forge.revision.number=") << tokenizer.GetNextToken() << "\n";
+		verFile << wxString("forge.build.number=") << tokenizer.GetNextToken() << "\n";
+		auto buf = verFile.ToUTF8();
+		outzip.Write(buf.data(), buf.length());
+		// check if we succeeded
+		return inzip.Eof() && outzip.Close() && out.Commit();
+	}
+	*/
+	return true;
+}
diff --git a/api/logic/minecraft/forge/LegacyForge.h b/api/logic/minecraft/forge/LegacyForge.h
new file mode 100644
index 00000000..f51d5e85
--- /dev/null
+++ b/api/logic/minecraft/forge/LegacyForge.h
@@ -0,0 +1,25 @@
+/* Copyright 2013-2015 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 "minecraft/Mod.h"
+
+class MinecraftForge : public Mod
+{
+public:
+	MinecraftForge(const QString &file);
+	bool FixVersionIfNeeded(QString newVersion);
+};