Rework the update checking system

CMakeLists.txt

@@ -118,20 +118,50 @@ SET(MultiMC_VERSION_MINOR		0)
 SET(MultiMC_VERSION_BUILD -1 CACHE STRING "Build number. -1 for no build number.")
 
 # Build type
-SET(MultiMC_VERSION_BUILD_TYPE "custombuild" CACHE STRING "Build type. Usually corresponds to the buildbot build name. Empty string for no build type.")
+SET(MultiMC_VERSION_BUILD_TYPE "custombuild" CACHE STRING "Build type. If this is set, it is appended to the end of the version string with a dash (<version string>-<build type>. It is not used for anything other than indicating in the version string what type of build this is (eg 'lin64').")
 
+# Version channel
+SET(MultiMC_VERSION_CHANNEL "" CACHE STRING "The current build's channel. Included in the version string.")
+
+# Channel list URL
+SET(MultiMC_CHANLIST_URL "" CACHE STRING "URL for the channel list.")
+
+# Updater enabled?
+SET(MultiMC_UPDATER false CACHE BOOL "Whether or not the update system is enabled. If this is enabled, you must also set MultiMC_CHANLIST_URL and MultiMC_VERSION_CHANNEL in order for it to work properly.")
+
+
+# Build a version string to display in the configure logs.
 SET(MultiMC_VERSION_STRING "${MultiMC_VERSION_MAJOR}.${MultiMC_VERSION_MINOR}")
-
 IF (MultiMC_VERSION_BUILD GREATER -1)
 	SET(MultiMC_VERSION_STRING "${MultiMC_VERSION_STRING}.${MultiMC_VERSION_BUILD}")
 ENDIF ()
-
+IF (NOT MultiMC_VERSION_CHANNEL STREQUAL "")
+	SET(MultiMC_VERSION_STRING "${MultiMC_VERSION_STRING}-${MultiMC_VERSION_CHANNEL}")
+ENDIF ()
 IF (NOT MultiMC_VERSION_BUILD_TYPE STREQUAL "")
 	SET(MultiMC_VERSION_STRING "${MultiMC_VERSION_STRING}-${MultiMC_VERSION_BUILD_TYPE}")
 ENDIF ()
 
 MESSAGE(STATUS "MultiMC 5 version ${MultiMC_VERSION_STRING}")
 
+# If the update system is enabled, make sure MultiMC_CHANLIST_URL and MultiMC_VERSION_CHANNEL are set.
+IF (MultiMC_UPDATER)
+	IF (MultiMC_VERSION_CHANNEL STREQUAL "")
+		MESSAGE(FATAL_ERROR "Update system is enabled, but MultiMC_VERSION_CHANNEL is not set.\n"
+							"Please ensure the CMake variables MultiMC_VERSION_CHANNEL, MultiMC_CHANLIST_URL, and MultiMC_VERSION_BUILD are set.")
+	ENDIF ()
+	IF (MultiMC_CHANLIST_URL STREQUAL "")
+		MESSAGE(FATAL_ERROR "Update system is enabled, but MultiMC_CHANLIST_URL is not set.\n"
+							"Please ensure the CMake variables MultiMC_VERSION_CHANNEL, MultiMC_CHANLIST_URL, and MultiMC_VERSION_BUILD are set.")
+	ENDIF ()
+	IF (MultiMC_VERSION_BUILD LESS 0)
+		MESSAGE(FATAL_ERROR "Update system is enabled, but MultiMC_VERSION_BUILD is not set.\n"
+							"Please ensure the CMake variables MultiMC_VERSION_CHANNEL, MultiMC_CHANLIST_URL, and MultiMC_VERSION_BUILD are set.")
+	ENDIF ()
+
+	MESSAGE(STATUS "Updater is enabled. Channel list URL: ${MultiMC_CHANLIST_URL}")
+ENDIF ()
+
 #### Custom target to just print the version.
 ADD_CUSTOM_TARGET(version echo "Version: ${MultiMC_VERSION_STRING}")
 
@@ -151,10 +181,6 @@ ELSE()
 	MESSAGE(STATUS "Failed to check Git commit. ${GIT_COMMIT_CHECK_RESULTVAR}")
 ENDIF()
 
-#### GoUpdate URL
-SET(MultiMC_REPO_BASE_URL "invalid" CACHE STRING "Base URL for the updater.")
-SET(MultiMC_VERSION_BRANCH "invalid" CACHE STRING "URL of the stable update repo.")
-
 ######## Configure header ########
 configure_file("${PROJECT_SOURCE_DIR}/config.h.in" "${PROJECT_BINARY_DIR}/include/config.h")
 
@@ -290,6 +316,10 @@ logic/auth/flows/ValidateTask.cpp
 logic/auth/flows/InvalidateTask.h
 logic/auth/flows/InvalidateTask.cpp
 
+# Update system
+logic/updater/UpdateChecker.h
+logic/updater/UpdateChecker.cpp
+
 # legacy instances
 logic/LegacyInstance.h
 logic/LegacyInstance.cpp
@@ -358,8 +388,6 @@ logic/NagUtils.h
 logic/NagUtils.cpp
 logic/SkinUtils.h
 logic/SkinUtils.cpp
-logic/GoUpdate.h
-logic/GoUpdate.cpp
 )
 
 

MultiMC.cpp

@@ -20,7 +20,8 @@
 #include "logic/net/HttpMetaCache.h"
 
 #include "logic/JavaUtils.h"
-#include "logic/GoUpdate.h"
+
+#include "logic/updater/UpdateChecker.h"
 
 #include "pathutils.h"
 #include "cmdutils.h"
@@ -33,7 +34,7 @@
 using namespace Util::Commandline;
 
 MultiMC::MultiMC(int &argc, char **argv) : QApplication(argc, argv),
-	m_version{VERSION_MAJOR, VERSION_MINOR, VERSION_BUILD, VERSION_BUILD_TYPE}
+	m_version{VERSION_MAJOR, VERSION_MINOR, VERSION_BUILD, VERSION_CHANNEL, VERSION_BUILD_TYPE}
 {
 	setOrganizationName("MultiMC");
 	setApplicationName("MultiMC5");
@@ -140,7 +141,7 @@ MultiMC::MultiMC(int &argc, char **argv) : QApplication(argc, argv),
 	initGlobalSettings();
 
 	// initialize the updater
-	m_go_update.reset(new GoUpdate());
+	m_updateChecker.reset(new UpdateChecker());
 
 	// and instances
 	auto InstDirSetting = m_settings->getSetting("InstanceDir");

MultiMC.h

@@ -17,7 +17,7 @@ class IconList;
 class QNetworkAccessManager;
 class ForgeVersionList;
 class JavaVersionList;
-class GoUpdate;
+class UpdateChecker;
 
 #if defined(MMC)
 #undef MMC
@@ -85,9 +85,9 @@ public:
 		return m_metacache;
 	}
 
-	std::shared_ptr<GoUpdate> goupdate()
+	std::shared_ptr<UpdateChecker> updateChecker()
 	{
-		return m_go_update;
+		return m_updateChecker;
 	}
 
 	std::shared_ptr<LWJGLVersionList> lwjgllist();
@@ -112,7 +112,7 @@ private:
 	std::shared_ptr<QTranslator> m_mmc_translator;
 	std::shared_ptr<SettingsObject> m_settings;
 	std::shared_ptr<InstanceList> m_instances;
-	std::shared_ptr<GoUpdate> m_go_update;
+	std::shared_ptr<UpdateChecker> m_updateChecker;
 	std::shared_ptr<MojangAccountList> m_accounts;
 	std::shared_ptr<IconList> m_icons;
 	std::shared_ptr<QNetworkAccessManager> m_qnam;

MultiMCVersion.h

@@ -32,8 +32,9 @@ struct MultiMCVersion
 				QString::number(major),
 				QString::number(minor));
 
-		if (build > 0) vstr += QString(".%1").arg(QString::number(build));
+		if (build >= 0) vstr += "." + QString::number(build);
-		if (!buildType.isEmpty()) vstr += QString("-%1").arg(buildType);
+		if (!channel.isEmpty()) vstr += "-" + channel;
+		if (!buildType.isEmpty()) vstr += "-" + buildType;
 
 		return vstr;
 	}
@@ -60,10 +61,14 @@ struct MultiMCVersion
 	 */
 	int build;
 
+	/*!
+	 * \brief This build's channel.
+	 */
+	QString channel;
+
 	/*!
 	 * \brief The build type.
-	 * This indicates the type of build that this is. For example, lin64-stable.
+	 * This indicates the type of build that this is. For example, lin64 or custombuild.
-	 * Usually corresponds to this build's buildbot builder name.
 	 */
 	QString buildType;
 };

config.h.in

@@ -2,19 +2,17 @@
 #define VERSION_MAJOR		@MultiMC_VERSION_MAJOR@
 #define VERSION_MINOR		@MultiMC_VERSION_MINOR@
 
-// Build number and type -- numer is used by the updater, type is purely visual
+// Build number, channel, and type -- number and channel are used by the updater, type is purely visual
 #define VERSION_BUILD		@MultiMC_VERSION_BUILD@
+#define VERSION_CHANNEL    "@MultiMC_VERSION_CHANNEL@"
 #define VERSION_BUILD_TYPE "@MultiMC_VERSION_BUILD_TYPE@"
 
-// URL base for the updater
+// URL for the updater's channel
-#define VERSION_REPO       "@MultiMC_REPO_BASE_URL@"
+#define CHANLIST_URL       "@MultiMC_CHANLIST_URL@"
 
-// The branch used for this build. User can switch between 'stable' and 'develop'
+// The commit hash of this build
-// if this is one of them. Otherwise,  it pulls only from this one.
-#define VERSION_BRANCH     "@MultiMC_VERSION_BRANCH@"
-
-// the commit hash of this build
 #define GIT_COMMIT		   "@MultiMC_GIT_COMMIT@"
 
 // This is printed on start to standard output
 #define VERSION_STR        "@MultiMC_VERSION_STRING@"
+

gui/MainWindow.cpp

@@ -84,7 +84,8 @@
 #include "logic/SkinUtils.h"
 
 #include "logic/LegacyInstance.h"
-#include <logic/GoUpdate.h>
+
+#include <logic/updater/UpdateChecker.h>
 
 MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow)
 {
@@ -239,8 +240,8 @@ MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWi
 		}
 
 		// set up the updater object.
-		auto updater = MMC->goupdate();
+		auto updater = MMC->updateChecker();
-		connect(updater.get(), SIGNAL(updateAvailable()), SLOT(updateAvailable()));
+		QObject::connect(updater.get(), &UpdateChecker::updateAvailable, this, &MainWindow::updateAvailable);
 		// if automatic update checks are allowed, start one.
 		if(MMC->settings()->get("AutoUpdate").toBool())
 			on_actionCheckUpdate_triggered();
@@ -426,7 +427,7 @@ bool MainWindow::eventFilter(QObject *obj, QEvent *ev)
 	return QMainWindow::eventFilter(obj, ev);
 }
 
-void MainWindow::updateAvailable()
+void MainWindow::updateAvailable(QString repo, QString versionName, int versionId)
 {
 	UpdateDialog dlg;
 	UpdateAction action = (UpdateAction) dlg.exec();
@@ -631,7 +632,7 @@ void MainWindow::on_actionConfig_Folder_triggered()
 
 void MainWindow::on_actionCheckUpdate_triggered()
 {
-	auto updater = MMC->goupdate();
+	auto updater = MMC->updateChecker();
 	updater->checkForUpdate();
 }
 

gui/MainWindow.h

@@ -161,7 +161,7 @@ slots:
 
 	void startTask(Task *task);
 
-	void updateAvailable();
+	void updateAvailable(QString repo, QString versionName, int versionId);
 
 	void activeAccountChanged();
 

logic/GoUpdate.cpp

@@ -1,99 +0,0 @@
-
-#include "GoUpdate.h"
-
-#include "config.h"
-#include "logger/QsLog.h"
-
-GoUpdate::GoUpdate()
-{
-	currentBuildIndex = VERSION_BUILD;
-	builderName = VERSION_BUILD_TYPE;
-	repoUrlBase = VERSION_REPO;
-}
-
-void GoUpdate::updateCheckFailed()
-{
-	// TODO: log errors better
-	QLOG_ERROR() << "Update check failed for reasons unknown.";
-}
-
-void GoUpdate::updateCheckFinished()
-{
-	QJsonParseError jsonError;
-	QByteArray data;
-	{
-		ByteArrayDownloadPtr dl =
-			std::dynamic_pointer_cast<ByteArrayDownload>(index_job->first());
-		data = dl->m_data;
-		index_job.reset();
-	}
-
-	QJsonDocument jsonDoc = QJsonDocument::fromJson(data, &jsonError);
-	if (jsonError.error != QJsonParseError::NoError || !jsonDoc.isObject())
-	{
-		return;
-	}
-
-	QVariant doc = jsonDoc.toVariant();
-	auto stuff = doc.toMap();
-
-	// check api version (or later, branch?)
-	int ApiVersion = stuff["ApiVersion"].toInt();
-	if (ApiVersion != 0)
-		return;
-
-	// parse and store the channel list
-	auto parsedChannels = stuff["Channels"].toList();
-	for (auto channel : parsedChannels)
-	{
-		auto chanMap = channel.toMap();
-		channels.append({chanMap["Id"].toString(), chanMap["Name"].toString(),
-						 chanMap["CurrentVersion"].toInt()});
-	}
-
-	// parse and store the version list
-	auto parsedVersions = stuff["Versions"].toList();
-	for (auto version : parsedVersions)
-	{
-		auto verMap = version.toMap();
-		int versionId = verMap["Id"].toInt();
-		versions.append({versionId, verMap["Name"].toString()});
-		if (currentBuildIndex < versionId)
-		{
-			newBuildIndex = versionId;
-		}
-	}
-
-	if (newBuildIndex != -1)
-	{
-		QLOG_INFO() << "Update is available.";
-		emit updateAvailable();
-	}
-	else
-	{
-		QLOG_INFO() << "Update check finished.";
-	}
-}
-
-void GoUpdate::checkForUpdate()
-{
-	if (repoUrlBase == "invalid")
-	{
-		return;
-	}
-
-	auto job = new NetJob("Assets index");
-	job->addNetAction(
-		ByteArrayDownload::make(QUrl(repoUrlBase + "/" + VERSION_BRANCH + "/index.json")));
-	connect(job, SIGNAL(succeeded()), SLOT(updateCheckFinished()));
-	connect(job, SIGNAL(failed()), SLOT(updateCheckFailed()));
-	index_job.reset(job);
-	job->start();
-}
-
-/*
-<Forkk> files.multimc.org/lin64/
-<manmaed> Hi Forkkie
-<Forkk> files.multimc.org/win32/
-<Forkk> files.multimc.org/lin32/
-*/

logic/GoUpdate.h

@@ -1,43 +0,0 @@
-#pragma once
-#include "net/NetJob.h"
-
-class GoUpdate : public QObject
-{
-	Q_OBJECT
-
-public:
-	struct version_channel
-	{
-		QString id;
-		QString name;
-		int latestVersion;
-	};
-
-	struct version_summary
-	{
-		int id;
-		QString name;
-	};
-
-signals:
-	void updateAvailable();
-
-private slots:
-	void updateCheckFinished();
-	void updateCheckFailed();
-
-public:
-	GoUpdate();
-	void checkForUpdate();
-private:
-	NetJobPtr index_job;
-	NetJobPtr fromto_job;
-
-	QString repoUrlBase;
-	QString builderName;
-	int currentBuildIndex;
-	int newBuildIndex = -1;
-
-	QList<version_summary> versions;
-	QList<version_channel> channels;
-};

logic/updater/UpdateChecker.cpp

@@ -0,0 +1,234 @@
+/* Copyright 2013 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 "UpdateChecker.h"
+
+#include "MultiMC.h"
+
+#include "config.h"
+#include "logger/QsLog.h"
+
+#include <QJsonObject>
+#include <QJsonArray>
+#include <QJsonValue>
+
+#define API_VERSION 0
+#define CHANLIST_FORMAT 0
+
+UpdateChecker::UpdateChecker()
+{
+	m_currentChannel = VERSION_CHANNEL;
+	m_channelListUrl = CHANLIST_URL;
+	m_updateChecking = false;
+	m_chanListLoading = false;
+	m_checkUpdateWaiting = false;
+	m_chanListLoaded = false;
+}
+
+void UpdateChecker::checkForUpdate()
+{
+	QLOG_DEBUG() << "Checking for updates.";
+
+	// If the channel list hasn't loaded yet, load it and defer checking for updates until later.
+	if (!m_chanListLoaded)
+	{
+		QLOG_DEBUG() << "Channel list isn't loaded yet. Loading channel list and deferring update check.";
+		m_checkUpdateWaiting = true;
+		updateChanList();
+		return;
+	}
+
+	if (m_updateChecking)
+	{
+		QLOG_DEBUG() << "Ignoring update check request. Already checking for updates.";
+		return;
+	}
+
+	m_updateChecking = true;
+
+	// Get the URL for the channel we're using.
+	// TODO: Allow user to select channels. For now, we'll just use the current channel.
+	QString updateChannel = m_currentChannel;
+
+	// Find the desired channel within the channel list and get its repo URL. If if cannot be found, error.
+	m_repoUrl = "";
+	for (ChannelListEntry entry : m_channels)
+	{
+		if (entry.id == updateChannel)
+			m_repoUrl = entry.url;
+	}
+
+	// If we didn't find our channel, error.
+	if (m_repoUrl.isEmpty())
+	{
+		emit updateCheckFailed();
+		return;
+	}
+
+	QUrl indexUrl = QUrl(m_repoUrl).resolved(QUrl("index.json"));
+
+	auto job = new NetJob("GoUpdate Repository Index");
+	job->addNetAction(ByteArrayDownload::make(indexUrl));
+	connect(job, SIGNAL(succeeded()), SLOT(updateCheckFinished()));
+	connect(job, SIGNAL(failed()), SLOT(updateCheckFailed()));
+	indexJob.reset(job);
+	job->start();
+}
+
+void UpdateChecker::updateCheckFinished()
+{
+	QLOG_DEBUG() << "Finished downloading repo index. Checking for new versions.";
+
+	QJsonParseError jsonError;
+	QByteArray data;
+	{
+		ByteArrayDownloadPtr dl = std::dynamic_pointer_cast<ByteArrayDownload>(indexJob->first());
+		data = dl->m_data;
+		indexJob.reset();
+	}
+
+	QJsonDocument jsonDoc = QJsonDocument::fromJson(data, &jsonError);
+	if (jsonError.error != QJsonParseError::NoError || !jsonDoc.isObject())
+	{
+		QLOG_ERROR() << "Failed to parse GoUpdate repository index. JSON error" << jsonError.errorString() << "at offset" << jsonError.offset;
+		return;
+	}
+
+	QJsonObject object = jsonDoc.object();
+
+	bool success = false;
+	int apiVersion = object.value("ApiVersion").toVariant().toInt(&success);
+	if (apiVersion != API_VERSION || !success)
+	{
+		QLOG_ERROR() << "Failed to check for updates. API version mismatch. We're using" << API_VERSION << "server has" << apiVersion;
+		return;
+	}
+
+	QLOG_DEBUG() << "Processing repository version list.";
+	QJsonObject newestVersion;
+	QJsonArray versions = object.value("Versions").toArray();
+	for (QJsonValue versionVal : versions)
+	{
+		QJsonObject version = versionVal.toObject();
+		if (newestVersion.value("Id").toVariant().toInt() < version.value("Id").toVariant().toInt())
+		{
+			QLOG_DEBUG() << "Found newer version with ID" << version.value("Id").toVariant().toInt();
+			newestVersion = version;
+		}
+	}
+
+	// We've got the version with the greatest ID number. Now compare it to our current build number and update if they're different.
+	int newBuildNumber = newestVersion.value("Id").toVariant().toInt();
+	if (newBuildNumber != MMC->version().build)
+	{
+		// Update!
+		emit updateAvailable(m_repoUrl, newestVersion.value("Name").toVariant().toString(), newBuildNumber);
+	}
+
+	m_updateChecking = false;
+}
+
+void UpdateChecker::updateCheckFailed()
+{
+	// TODO: log errors better
+	QLOG_ERROR() << "Update check failed for reasons unknown.";
+}
+
+void UpdateChecker::updateChanList()
+{
+	QLOG_DEBUG() << "Loading the channel list.";
+
+	if (m_channelListUrl.isEmpty())
+	{
+		QLOG_ERROR() << "Failed to update channel list. No channel list URL set."
+					 << "If you'd like to use MultiMC's update system, please pass the channel list URL to CMake at compile time.";
+		return;
+	}
+
+	m_chanListLoading = true;
+	NetJob* job = new NetJob("Update System Channel List");
+	job->addNetAction(ByteArrayDownload::make(QUrl(m_channelListUrl)));
+	QObject::connect(job, &NetJob::succeeded, this, &UpdateChecker::chanListDownloadFinished);
+	QObject::connect(job, &NetJob::failed, this, &UpdateChecker::chanListDownloadFailed);
+	chanListJob.reset(job);
+	job->start();
+}
+
+void UpdateChecker::chanListDownloadFinished()
+{
+	QByteArray data;
+	{
+		ByteArrayDownloadPtr dl = std::dynamic_pointer_cast<ByteArrayDownload>(chanListJob->first());
+		data = dl->m_data;
+		chanListJob.reset();
+	}
+
+	QJsonParseError jsonError;
+	QJsonDocument jsonDoc = QJsonDocument::fromJson(data, &jsonError);
+	if (jsonError.error != QJsonParseError::NoError)
+	{
+		// TODO: Report errors to the user.
+		QLOG_ERROR() << "Failed to parse channel list JSON:" << jsonError.errorString() << "at" << jsonError.offset;
+		return;
+	}
+	
+	QJsonObject object = jsonDoc.object();
+
+	bool success = false;
+	int formatVersion = object.value("format_version").toVariant().toInt(&success);
+	if (formatVersion != CHANLIST_FORMAT || !success)
+	{
+		QLOG_ERROR() << "Failed to check for updates. Channel list format version mismatch. We're using" << CHANLIST_FORMAT << "server has" << formatVersion;
+		return;
+	}
+
+	// Load channels into a temporary array.
+	QList<ChannelListEntry> loadedChannels;
+	QJsonArray channelArray = object.value("channels").toArray();
+	for (QJsonValue chanVal : channelArray)
+	{
+		QJsonObject channelObj = chanVal.toObject();
+		ChannelListEntry entry{
+				channelObj.value("id").toVariant().toString(),
+				channelObj.value("name").toVariant().toString(),
+				channelObj.value("description").toVariant().toString(),
+				channelObj.value("url").toVariant().toString()
+			};
+		if (entry.id.isEmpty() || entry.name.isEmpty() || entry.url.isEmpty())
+		{
+			QLOG_ERROR() << "Channel list entry with empty ID, name, or URL. Skipping.";
+			continue;
+		}
+		loadedChannels.append(entry);
+	}
+
+	// Swap  the channel list we just loaded into the object's channel list.
+	m_channels.swap(loadedChannels);
+
+	m_chanListLoading = false;
+	m_chanListLoaded = true;
+	QLOG_INFO() << "Successfully loaded UpdateChecker channel list.";
+
+	// If we're waiting to check for updates, do that now.
+	if (m_checkUpdateWaiting)
+		checkForUpdate();
+}
+
+void UpdateChecker::chanListDownloadFailed()
+{
+	m_chanListLoading = false;
+	QLOG_ERROR() << "Failed to download channel list.";
+}
+

logic/updater/UpdateChecker.h

@@ -0,0 +1,93 @@
+/* Copyright 2013 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/net/NetJob.h"
+
+#include <QUrl>
+
+class UpdateChecker : public QObject
+{
+	Q_OBJECT
+
+public:
+signals:
+	//! Signal emitted when an update is available. Passes the URL for the repo and the ID and name for the version.
+	void updateAvailable(QString repoUrl, QString versionName, int versionId);
+
+private slots:
+	void updateCheckFinished();
+	void updateCheckFailed();
+
+	void chanListDownloadFinished();
+	void chanListDownloadFailed();
+
+public:
+	UpdateChecker();
+	void checkForUpdate();
+
+	/*!
+	 * Causes the update checker to download the channel list from the URL specified in config.h (generated by CMake).
+	 * If this isn't called before checkForUpdate(), it will automatically be called.
+	 */
+	void updateChanList();
+
+	/*!
+	 * An entry in the channel list.
+	 */
+	struct ChannelListEntry
+	{
+		QString id;
+		QString name;
+		QString description;
+		QString url;
+	};
+
+private:
+	NetJobPtr indexJob;
+	NetJobPtr chanListJob;
+
+	QString m_repoUrl;
+
+	QString m_channelListUrl;
+	QString m_currentChannel;
+
+	QList<ChannelListEntry> m_channels;
+
+	/*!
+	 * True while the system is checking for updates.
+	 * If checkForUpdate is called while this is true, it will be ignored.
+	 */
+	bool m_updateChecking;
+
+	/*!
+	 * True if the channel list has loaded.
+	 * If this is false, trying to check for updates will call updateChanList first.
+	 */
+	bool m_chanListLoaded;
+
+	/*!
+	 * Set to true while the channel list is currently loading.
+	 */
+	bool m_chanListLoading;
+
+	/*!
+	 * Set to true when checkForUpdate is called while the channel list isn't loaded.
+	 * When the channel list finishes loading, if this is true, the update checker will check for updates.
+	 */
+	bool m_checkUpdateWaiting;
+};
+