From 6cb15706f5eee546ef357a8cefd99be87168619a Mon Sep 17 00:00:00 2001
From: "Vladimir Golovnev (Glassez)" <glassez@yandex.ru>
Date: Fri, 1 Mar 2019 10:38:16 +0300
Subject: [PATCH] Reduce number of DownloadManager signals

---
 src/base/bittorrent/session.cpp               | 34 ++++----
 src/base/bittorrent/session.h                 |  9 +-
 src/base/net/dnsupdater.cpp                   | 38 +++------
 src/base/net/dnsupdater.h                     |  8 +-
 src/base/net/downloadhandler.cpp              | 85 +++++++++----------
 src/base/net/downloadhandler.h                |  8 +-
 src/base/net/downloadmanager.cpp              | 11 ---
 src/base/net/downloadmanager.h                | 21 ++++-
 src/base/net/geoipmanager.cpp                 | 36 +++-----
 src/base/net/geoipmanager.h                   |  8 +-
 src/base/rss/rss_feed.cpp                     | 45 +++++-----
 src/base/rss/rss_feed.h                       | 10 ++-
 src/base/search/searchpluginmanager.cpp       | 54 +++++-------
 src/base/search/searchpluginmanager.h         | 11 ++-
 src/gui/addnewtorrentdialog.cpp               | 64 +++++++-------
 src/gui/addnewtorrentdialog.h                 | 12 ++-
 src/gui/mainwindow.cpp                        | 37 ++++----
 src/gui/mainwindow.h                          |  8 +-
 src/gui/programupdater.cpp                    | 24 +++---
 src/gui/programupdater.h                      |  9 +-
 src/gui/properties/trackersadditiondialog.cpp | 27 +++---
 src/gui/properties/trackersadditiondialog.h   |  8 +-
 src/gui/search/pluginselectdialog.cpp         | 22 +++--
 src/gui/search/pluginselectdialog.h           | 11 ++-
 src/gui/transferlistfilterswidget.cpp         | 37 ++++----
 src/gui/transferlistfilterswidget.h           | 11 ++-
 26 files changed, 314 insertions(+), 334 deletions(-)

diff --git a/src/base/bittorrent/session.cpp b/src/base/bittorrent/session.cpp
index 95d5d2708..0c1d7290a 100644
--- a/src/base/bittorrent/session.cpp
+++ b/src/base/bittorrent/session.cpp
@@ -1542,22 +1542,21 @@ void Session::processShareLimits()
     }
 }
 
-void Session::handleDownloadFailed(const QString &url, const QString &reason)
-{
-    emit downloadFromUrlFailed(url, reason);
-}
-
-void Session::handleRedirectedToMagnet(const QString &url, const QString &magnetUri)
-{
-    addTorrent_impl(CreateTorrentParams(m_downloadedTorrents.take(url)), MagnetUri(magnetUri));
-}
-
 // Add to BitTorrent session the downloaded torrent file
-void Session::handleDownloadFinished(const QString &url, const QByteArray &data)
+void Session::handleDownloadFinished(const Net::DownloadResult &result)
 {
-    emit downloadFromUrlFinished(url);
-    addTorrent_impl(CreateTorrentParams(m_downloadedTorrents.take(url))
-                    , MagnetUri(), TorrentInfo::load(data));
+    switch (result.status) {
+    case Net::DownloadStatus::Success:
+        emit downloadFromUrlFinished(result.url);
+        addTorrent_impl(CreateTorrentParams(m_downloadedTorrents.take(result.url))
+                        , MagnetUri(), TorrentInfo::load(result.data));
+        break;
+    case Net::DownloadStatus::RedirectedToMagnet:
+        addTorrent_impl(CreateTorrentParams(m_downloadedTorrents.take(result.url)), MagnetUri(result.magnet));
+        break;
+    default:
+        emit downloadFromUrlFailed(result.url, result.errorString);
+    }
 }
 
 // Return the torrent handle, given its hash
@@ -1796,11 +1795,8 @@ bool Session::addTorrent(const QString &source, const AddTorrentParams &params)
         LogMsg(tr("Downloading '%1', please wait...", "e.g: Downloading 'xxx.torrent', please wait...").arg(source));
         // Launch downloader
         const Net::DownloadHandler *handler =
-                Net::DownloadManager::instance()->download(Net::DownloadRequest(source).limit(10485760 /* 10MB */).handleRedirectToMagnet(true));
-        connect(handler, static_cast<void (Net::DownloadHandler::*)(const QString &, const QByteArray &)>(&Net::DownloadHandler::downloadFinished)
-                , this, &Session::handleDownloadFinished);
-        connect(handler, &Net::DownloadHandler::downloadFailed, this, &Session::handleDownloadFailed);
-        connect(handler, &Net::DownloadHandler::redirectedToMagnet, this, &Session::handleRedirectedToMagnet);
+                Net::DownloadManager::instance()->download(Net::DownloadRequest(source).limit(10485760 /* 10MB */));
+        connect(handler, &Net::DownloadHandler::finished, this, &Session::handleDownloadFinished);
         m_downloadedTorrents[handler->url()] = params;
         return true;
     }
diff --git a/src/base/bittorrent/session.h b/src/base/bittorrent/session.h
index 45629acd2..dc9103e7d 100644
--- a/src/base/bittorrent/session.h
+++ b/src/base/bittorrent/session.h
@@ -118,6 +118,11 @@ enum TorrentExportFolder
     Finished
 };
 
+namespace Net
+{
+    struct DownloadResult;
+}
+
 namespace BitTorrent
 {
     class InfoHash;
@@ -537,9 +542,7 @@ namespace BitTorrent
         void generateResumeData(bool final = false);
         void handleIPFilterParsed(int ruleCount);
         void handleIPFilterError();
-        void handleDownloadFinished(const QString &url, const QByteArray &data);
-        void handleDownloadFailed(const QString &url, const QString &reason);
-        void handleRedirectedToMagnet(const QString &url, const QString &magnetUri);
+        void handleDownloadFinished(const Net::DownloadResult &result);
 
         // Session reconfiguration triggers
         void networkOnlineStateChanged(bool online);
diff --git a/src/base/net/dnsupdater.cpp b/src/base/net/dnsupdater.cpp
index a262b5c65..6479c7d63 100644
--- a/src/base/net/dnsupdater.cpp
+++ b/src/base/net/dnsupdater.cpp
@@ -76,19 +76,20 @@ void DNSUpdater::checkPublicIP()
 
     DownloadHandler *handler = DownloadManager::instance()->download(
                 DownloadRequest("http://checkip.dyndns.org").userAgent("qBittorrent/" QBT_VERSION_2));
-    connect(handler, static_cast<void (Net::DownloadHandler::*)(const QString &, const QByteArray &)>(&Net::DownloadHandler::downloadFinished)
-            , this, &DNSUpdater::ipRequestFinished);
-    connect(handler, &Net::DownloadHandler::downloadFailed, this, &DNSUpdater::ipRequestFailed);
+    connect(handler, &DownloadHandler::finished, this, &DNSUpdater::ipRequestFinished);
 
     m_lastIPCheckTime = QDateTime::currentDateTime();
 }
 
-void DNSUpdater::ipRequestFinished(const QString &url, const QByteArray &data)
+void DNSUpdater::ipRequestFinished(const DownloadResult &result)
 {
-    Q_UNUSED(url);
+    if (result.status != DownloadStatus::Success) {
+        qWarning() << "IP request failed:" << result.errorString;
+        return;
+    }
 
     // Parse response
-    const QRegularExpressionMatch ipRegexMatch = QRegularExpression("Current IP Address:\\s+([^<]+)</body>").match(data);
+    const QRegularExpressionMatch ipRegexMatch = QRegularExpression("Current IP Address:\\s+([^<]+)</body>").match(result.data);
     if (ipRegexMatch.hasMatch()) {
         QString ipStr = ipRegexMatch.captured(1);
         qDebug() << Q_FUNC_INFO << "Regular expression captured the following IP:" << ipStr;
@@ -110,12 +111,6 @@ void DNSUpdater::ipRequestFinished(const QString &url, const QByteArray &data)
     }
 }
 
-void DNSUpdater::ipRequestFailed(const QString &url, const QString &error)
-{
-    Q_UNUSED(url);
-    qWarning() << "IP request failed:" << error;
-}
-
 void DNSUpdater::updateDNSService()
 {
     qDebug() << Q_FUNC_INFO;
@@ -123,9 +118,7 @@ void DNSUpdater::updateDNSService()
     m_lastIPCheckTime = QDateTime::currentDateTime();
     DownloadHandler *handler = DownloadManager::instance()->download(
                 DownloadRequest(getUpdateUrl()).userAgent("qBittorrent/" QBT_VERSION_2));
-    connect(handler, static_cast<void (Net::DownloadHandler::*)(const QString &, const QByteArray &)>(&Net::DownloadHandler::downloadFinished)
-            , this, &DNSUpdater::ipUpdateFinished);
-    connect(handler, &Net::DownloadHandler::downloadFailed, this, &DNSUpdater::ipUpdateFailed);
+    connect(handler, &DownloadHandler::finished, this, &DNSUpdater::ipUpdateFinished);
 }
 
 QString DNSUpdater::getUpdateUrl() const
@@ -164,17 +157,12 @@ QString DNSUpdater::getUpdateUrl() const
     return url.toString();
 }
 
-void DNSUpdater::ipUpdateFinished(const QString &url, const QByteArray &data)
-{
-    Q_UNUSED(url);
-    // Parse reply
-    processIPUpdateReply(data);
-}
-
-void DNSUpdater::ipUpdateFailed(const QString &url, const QString &error)
+void DNSUpdater::ipUpdateFinished(const DownloadResult &result)
 {
-    Q_UNUSED(url);
-    qWarning() << "IP update failed:" << error;
+    if (result.status == DownloadStatus::Success)
+        processIPUpdateReply(result.data);
+    else
+        qWarning() << "IP update failed:" << result.errorString;
 }
 
 void DNSUpdater::processIPUpdateReply(const QString &reply)
diff --git a/src/base/net/dnsupdater.h b/src/base/net/dnsupdater.h
index 99002fdc9..54459e4da 100644
--- a/src/base/net/dnsupdater.h
+++ b/src/base/net/dnsupdater.h
@@ -38,6 +38,8 @@
 
 namespace Net
 {
+    struct DownloadResult;
+
     // Based on http://www.dyndns.com/developers/specs/
     class DNSUpdater : public QObject
     {
@@ -54,11 +56,9 @@ namespace Net
 
     private slots:
         void checkPublicIP();
-        void ipRequestFinished(const QString &url, const QByteArray &data);
-        void ipRequestFailed(const QString &url, const QString &error);
+        void ipRequestFinished(const DownloadResult &result);
         void updateDNSService();
-        void ipUpdateFinished(const QString &url, const QByteArray &data);
-        void ipUpdateFailed(const QString &url, const QString &error);
+        void ipUpdateFinished(const DownloadResult &result);
 
     private:
         enum State
diff --git a/src/base/net/downloadhandler.cpp b/src/base/net/downloadhandler.cpp
index d94efe22c..78de6109d 100644
--- a/src/base/net/downloadhandler.cpp
+++ b/src/base/net/downloadhandler.cpp
@@ -69,6 +69,8 @@ Net::DownloadHandler::DownloadHandler(QNetworkReply *reply, DownloadManager *man
 {
     if (reply)
         assignNetworkReply(reply);
+    m_result.url = url();
+    m_result.status = DownloadStatus::Success;
 }
 
 Net::DownloadHandler::~DownloadHandler()
@@ -103,8 +105,8 @@ void Net::DownloadHandler::processFinishedDownload()
     if (m_reply->error() != QNetworkReply::NoError) {
         // Failure
         qDebug("Download failure (%s), reason: %s", qUtf8Printable(url), qUtf8Printable(errorCodeToString(m_reply->error())));
-        emit downloadFailed(m_downloadRequest.url(), errorCodeToString(m_reply->error()));
-        this->deleteLater();
+        setError(errorCodeToString(m_reply->error()));
+        finish();
         return;
     }
 
@@ -117,49 +119,43 @@ void Net::DownloadHandler::processFinishedDownload()
     }
 
     // Success
-    const QByteArray replyData = (m_reply->rawHeader("Content-Encoding") == "gzip")
+    m_result.data = (m_reply->rawHeader("Content-Encoding") == "gzip")
         ? Utils::Gzip::decompress(m_reply->readAll())
         : m_reply->readAll();
 
     if (m_downloadRequest.saveToFile()) {
         QString filePath;
-        if (saveToFile(replyData, filePath))
-            emit downloadFinished(m_downloadRequest.url(), filePath);
+        if (saveToFile(m_result.data, filePath))
+            m_result.filePath = filePath;
         else
-            emit downloadFailed(m_downloadRequest.url(), tr("I/O Error"));
-    }
-    else {
-        emit downloadFinished(m_downloadRequest.url(), replyData);
+            setError(tr("I/O Error"));
     }
 
-    this->deleteLater();
+    finish();
 }
 
 void Net::DownloadHandler::checkDownloadSize(const qint64 bytesReceived, const qint64 bytesTotal)
 {
-    QString msg = tr("The file size is %1. It exceeds the download limit of %2.");
-
-    if (bytesTotal > 0) {
+    if ((bytesTotal > 0) && (bytesTotal <= m_downloadRequest.limit())) {
         // Total number of bytes is available
-        if (bytesTotal > m_downloadRequest.limit()) {
-            m_reply->abort();
-            emit downloadFailed(m_downloadRequest.url(), msg.arg(Utils::Misc::friendlyUnit(bytesTotal), Utils::Misc::friendlyUnit(m_downloadRequest.limit())));
-        }
-        else {
-            disconnect(m_reply, &QNetworkReply::downloadProgress, this, &Net::DownloadHandler::checkDownloadSize);
-        }
+        disconnect(m_reply, &QNetworkReply::downloadProgress, this, &Net::DownloadHandler::checkDownloadSize);
+        return;
     }
-    else if (bytesReceived > m_downloadRequest.limit()) {
+
+    if ((bytesTotal > m_downloadRequest.limit()) || (bytesReceived > m_downloadRequest.limit())) {
         m_reply->abort();
-        emit downloadFailed(m_downloadRequest.url(), msg.arg(Utils::Misc::friendlyUnit(bytesReceived), Utils::Misc::friendlyUnit(m_downloadRequest.limit())));
+        setError(tr("The file size is %1. It exceeds the download limit of %2.")
+                 .arg(Utils::Misc::friendlyUnit(bytesTotal)
+                      , Utils::Misc::friendlyUnit(m_downloadRequest.limit())));
+        finish();
     }
 }
 
 void Net::DownloadHandler::handleRedirection(const QUrl &newUrl)
 {
     if (m_redirectionCounter >= MAX_REDIRECTIONS) {
-        emit downloadFailed(url(), tr("Exceeded max redirections (%1)").arg(MAX_REDIRECTIONS));
-        this->deleteLater();
+        setError(tr("Exceeded max redirections (%1)").arg(MAX_REDIRECTIONS));
+        finish();
         return;
     }
 
@@ -172,38 +168,35 @@ void Net::DownloadHandler::handleRedirection(const QUrl &newUrl)
     if (newUrlString.startsWith("magnet:", Qt::CaseInsensitive)) {
         qDebug("Magnet redirect detected.");
         m_reply->abort();
-        if (m_downloadRequest.handleRedirectToMagnet())
-            emit redirectedToMagnet(m_downloadRequest.url(), newUrlString);
-        else
-            emit downloadFailed(m_downloadRequest.url(), tr("Unexpected redirect to magnet URI."));
+        m_result.status = DownloadStatus::RedirectedToMagnet;
+        m_result.magnet = newUrlString;
 
-        this->deleteLater();
+        finish();
         return;
     }
 
     DownloadHandler *redirected = m_manager->download(DownloadRequest(m_downloadRequest).url(newUrlString));
     redirected->m_redirectionCounter = (m_redirectionCounter + 1);
-    connect(redirected, &DownloadHandler::destroyed, this, &DownloadHandler::deleteLater);
-    connect(redirected, &DownloadHandler::downloadFailed, this, [this](const QString &, const QString &reason)
-    {
-        emit downloadFailed(url(), reason);
-    });
-    connect(redirected, &DownloadHandler::redirectedToMagnet, this, [this](const QString &, const QString &magnetUri)
-    {
-        emit redirectedToMagnet(url(), magnetUri);
-    });
-    connect(redirected, static_cast<void (DownloadHandler::*)(const QString &, const QString &)>(&DownloadHandler::downloadFinished)
-            , this, [this](const QString &, const QString &fileName)
+    connect(redirected, &DownloadHandler::finished, this, [this](const DownloadResult &result)
     {
-        emit downloadFinished(url(), fileName);
-    });
-    connect(redirected, static_cast<void (DownloadHandler::*)(const QString &, const QByteArray &)>(&DownloadHandler::downloadFinished)
-            , this, [this](const QString &, const QByteArray &data)
-    {
-        emit downloadFinished(url(), data);
+        m_result = result;
+        m_result.url = url();
+        finish();
     });
 }
 
+void Net::DownloadHandler::setError(const QString &error)
+{
+    m_result.errorString = error;
+    m_result.status = DownloadStatus::Failed;
+}
+
+void Net::DownloadHandler::finish()
+{
+    emit finished(m_result);
+    deleteLater();
+}
+
 QString Net::DownloadHandler::errorCodeToString(const QNetworkReply::NetworkError status)
 {
     switch (status) {
diff --git a/src/base/net/downloadhandler.h b/src/base/net/downloadhandler.h
index cd13a8448..113920ad6 100644
--- a/src/base/net/downloadhandler.h
+++ b/src/base/net/downloadhandler.h
@@ -56,10 +56,7 @@ namespace Net
         QString url() const;
 
     signals:
-        void downloadFinished(const QString &url, const QByteArray &data);
-        void downloadFinished(const QString &url, const QString &filePath);
-        void downloadFailed(const QString &url, const QString &reason);
-        void redirectedToMagnet(const QString &url, const QString &magnetUri);
+        void finished(const DownloadResult &result);
 
     private slots:
         void processFinishedDownload();
@@ -68,6 +65,8 @@ namespace Net
     private:
         void assignNetworkReply(QNetworkReply *reply);
         void handleRedirection(const QUrl &newUrl);
+        void setError(const QString &error);
+        void finish();
 
         static QString errorCodeToString(QNetworkReply::NetworkError status);
 
@@ -75,6 +74,7 @@ namespace Net
         DownloadManager *m_manager;
         const DownloadRequest m_downloadRequest;
         short m_redirectionCounter = 0;
+        DownloadResult m_result;
     };
 }
 
diff --git a/src/base/net/downloadmanager.cpp b/src/base/net/downloadmanager.cpp
index 680d2e233..eb9eb924d 100644
--- a/src/base/net/downloadmanager.cpp
+++ b/src/base/net/downloadmanager.cpp
@@ -328,17 +328,6 @@ Net::DownloadRequest &Net::DownloadRequest::saveToFile(const bool value)
     return *this;
 }
 
-bool Net::DownloadRequest::handleRedirectToMagnet() const
-{
-    return m_handleRedirectToMagnet;
-}
-
-Net::DownloadRequest &Net::DownloadRequest::handleRedirectToMagnet(const bool value)
-{
-    m_handleRedirectToMagnet = value;
-    return *this;
-}
-
 Net::ServiceID Net::ServiceID::fromURL(const QUrl &url)
 {
     return {url.host(), url.port(80)};
diff --git a/src/base/net/downloadmanager.h b/src/base/net/downloadmanager.h
index 3e83dbc3f..1ff70dbde 100644
--- a/src/base/net/downloadmanager.h
+++ b/src/base/net/downloadmanager.h
@@ -64,15 +64,28 @@ namespace Net
         bool saveToFile() const;
         DownloadRequest &saveToFile(bool value);
 
-        bool handleRedirectToMagnet() const;
-        DownloadRequest &handleRedirectToMagnet(bool value);
-
     private:
         QString m_url;
         QString m_userAgent;
         qint64 m_limit = 0;
         bool m_saveToFile = false;
-        bool m_handleRedirectToMagnet = false;
+    };
+
+    enum class DownloadStatus
+    {
+        Success,
+        RedirectedToMagnet,
+        Failed
+    };
+
+    struct DownloadResult
+    {
+        QString url;
+        DownloadStatus status;
+        QString errorString;
+        QByteArray data;
+        QString filePath;
+        QString magnet;
     };
 
     struct ServiceID
diff --git a/src/base/net/geoipmanager.cpp b/src/base/net/geoipmanager.cpp
index 541ebad0d..23cc151f7 100644
--- a/src/base/net/geoipmanager.cpp
+++ b/src/base/net/geoipmanager.cpp
@@ -119,9 +119,7 @@ void GeoIPManager::manageDatabaseUpdate()
 void GeoIPManager::downloadDatabaseFile()
 {
     const DownloadHandler *handler = DownloadManager::instance()->download({DATABASE_URL});
-    connect(handler, static_cast<void (Net::DownloadHandler::*)(const QString &, const QByteArray &)>(&Net::DownloadHandler::downloadFinished)
-            , this, &GeoIPManager::downloadFinished);
-    connect(handler, &Net::DownloadHandler::downloadFailed, this, &GeoIPManager::downloadFailed);
+    connect(handler, &DownloadHandler::finished, this, &GeoIPManager::downloadFinished);
 }
 
 QString GeoIPManager::lookup(const QHostAddress &hostAddr) const
@@ -413,14 +411,17 @@ void GeoIPManager::configure()
     }
 }
 
-void GeoIPManager::downloadFinished(const QString &url, QByteArray data)
+void GeoIPManager::downloadFinished(const DownloadResult &result)
 {
-    Q_UNUSED(url);
+    if (result.status != DownloadStatus::Success) {
+        LogMsg(tr("Couldn't download GeoIP database file. Reason: %1").arg(result.errorString), Log::WARNING);
+        return;
+    }
 
     bool ok = false;
-    data = Utils::Gzip::decompress(data, &ok);
+    const QByteArray data = Utils::Gzip::decompress(result.data, &ok);
     if (!ok) {
-        Logger::instance()->addMessage(tr("Could not decompress GeoIP database file."), Log::WARNING);
+        LogMsg(tr("Could not decompress GeoIP database file."), Log::WARNING);
         return;
     }
 
@@ -431,7 +432,7 @@ void GeoIPManager::downloadFinished(const QString &url, QByteArray data)
             if (m_geoIPDatabase)
                 delete m_geoIPDatabase;
             m_geoIPDatabase = geoIPDatabase;
-            Logger::instance()->addMessage(tr("GeoIP database loaded. Type: %1. Build time: %2.")
+            LogMsg(tr("GeoIP database loaded. Type: %1. Build time: %2.")
                 .arg(m_geoIPDatabase->type(), m_geoIPDatabase->buildEpoch().toString()),
                 Log::INFO);
             const QString targetPath = Utils::Fs::expandPathAbs(
@@ -439,25 +440,16 @@ void GeoIPManager::downloadFinished(const QString &url, QByteArray data)
             if (!QDir(targetPath).exists())
                 QDir().mkpath(targetPath);
             QFile targetFile(QString("%1/%2").arg(targetPath, GEOIP_FILENAME));
-            if (!targetFile.open(QFile::WriteOnly) || (targetFile.write(data) == -1)) {
-                Logger::instance()->addMessage(
-                            tr("Couldn't save downloaded GeoIP database file."), Log::WARNING);
-            }
-            else {
-                Logger::instance()->addMessage(tr("Successfully updated GeoIP database."), Log::INFO);
-            }
+            if (!targetFile.open(QFile::WriteOnly) || (targetFile.write(data) == -1))
+                LogMsg(tr("Couldn't save downloaded GeoIP database file."), Log::WARNING);
+            else
+                LogMsg(tr("Successfully updated GeoIP database."), Log::INFO);
         }
         else {
             delete geoIPDatabase;
         }
     }
     else {
-        Logger::instance()->addMessage(tr("Couldn't load GeoIP database. Reason: %1").arg(error), Log::WARNING);
+        LogMsg(tr("Couldn't load GeoIP database. Reason: %1").arg(error), Log::WARNING);
     }
 }
-
-void GeoIPManager::downloadFailed(const QString &url, const QString &reason)
-{
-    Q_UNUSED(url);
-    Logger::instance()->addMessage(tr("Couldn't download GeoIP database file. Reason: %1").arg(reason), Log::WARNING);
-}
diff --git a/src/base/net/geoipmanager.h b/src/base/net/geoipmanager.h
index b185354e2..ef9ef5a4d 100644
--- a/src/base/net/geoipmanager.h
+++ b/src/base/net/geoipmanager.h
@@ -40,9 +40,12 @@ class GeoIPDatabase;
 
 namespace Net
 {
+    struct DownloadResult;
+
     class GeoIPManager : public QObject
     {
         Q_OBJECT
+        Q_DISABLE_COPY(GeoIPManager)
 
     public:
         static void initInstance();
@@ -55,12 +58,11 @@ namespace Net
 
     private slots:
         void configure();
-        void downloadFinished(const QString &url, QByteArray data);
-        void downloadFailed(const QString &url, const QString &reason);
+        void downloadFinished(const DownloadResult &result);
 
     private:
         GeoIPManager();
-        ~GeoIPManager();
+        ~GeoIPManager() override;
 
         void loadDatabase();
         void manageDatabaseUpdate();
diff --git a/src/base/rss/rss_feed.cpp b/src/base/rss/rss_feed.cpp
index d2c785522..4a2c6c298 100644
--- a/src/base/rss/rss_feed.cpp
+++ b/src/base/rss/rss_feed.cpp
@@ -131,10 +131,7 @@ void Feed::refresh()
     // NOTE: Should we allow manually refreshing for disabled session?
 
     Net::DownloadHandler *handler = Net::DownloadManager::instance()->download(m_url);
-    connect(handler
-            , static_cast<void (Net::DownloadHandler::*)(const QString &, const QByteArray &)>(&Net::DownloadHandler::downloadFinished)
-            , this, &Feed::handleDownloadFinished);
-    connect(handler, &Net::DownloadHandler::downloadFailed, this, &Feed::handleDownloadFailed);
+    connect(handler, &Net::DownloadHandler::finished, this, &Feed::handleDownloadFinished);
 
     m_isLoading = true;
     emit stateChanged(this);
@@ -182,12 +179,12 @@ void Feed::handleMaxArticlesPerFeedChanged(const int n)
     // We don't need store articles here
 }
 
-void Feed::handleIconDownloadFinished(const QString &url, const QString &filePath)
+void Feed::handleIconDownloadFinished(const Net::DownloadResult &result)
 {
-    Q_UNUSED(url);
-
-    m_iconPath = Utils::Fs::fromNativePath(filePath);
-    emit iconLoaded(this);
+    if (result.status == Net::DownloadStatus::Success) {
+        m_iconPath = Utils::Fs::fromNativePath(result.filePath);
+        emit iconLoaded(this);
+    }
 }
 
 bool Feed::hasError() const
@@ -195,22 +192,22 @@ bool Feed::hasError() const
     return m_hasError;
 }
 
-void Feed::handleDownloadFinished(const QString &url, const QByteArray &data)
-{
-    qDebug() << "Successfully downloaded RSS feed at" << url;
-    // Parse the download RSS
-    m_parser->parse(data);
-}
-
-void Feed::handleDownloadFailed(const QString &url, const QString &error)
+void Feed::handleDownloadFinished(const Net::DownloadResult &result)
 {
-    m_isLoading = false;
-    m_hasError = true;
+    if (result.status == Net::DownloadStatus::Success) {
+        qDebug() << "Successfully downloaded RSS feed at" << result.url;
+        // Parse the download RSS
+        m_parser->parse(result.data);
+    }
+    else {
+        m_isLoading = false;
+        m_hasError = true;
 
-    LogMsg(tr("Failed to download RSS feed at '%1'. Reason: %2").arg(url, error)
-           , Log::WARNING);
+        LogMsg(tr("Failed to download RSS feed at '%1'. Reason: %2")
+               .arg(result.url, result.errorString), Log::WARNING);
 
-    emit stateChanged(this);
+        emit stateChanged(this);
+    }
 }
 
 void Feed::handleParsingFinished(const RSS::Private::ParsingResult &result)
@@ -404,9 +401,7 @@ void Feed::downloadIcon()
     const auto iconUrl = QString("%1://%2/favicon.ico").arg(url.scheme(), url.host());
     const Net::DownloadHandler *handler = Net::DownloadManager::instance()->download(
             Net::DownloadRequest(iconUrl).saveToFile(true));
-    connect(handler
-            , static_cast<void (Net::DownloadHandler::*)(const QString &, const QString &)>(&Net::DownloadHandler::downloadFinished)
-            , this, &Feed::handleIconDownloadFinished);
+    connect(handler, &Net::DownloadHandler::finished, this, &Feed::handleIconDownloadFinished);
 }
 
 int Feed::updateArticles(const QList<QVariantHash> &loadedArticles)
diff --git a/src/base/rss/rss_feed.h b/src/base/rss/rss_feed.h
index 3e75ab3b9..140d3aa92 100644
--- a/src/base/rss/rss_feed.h
+++ b/src/base/rss/rss_feed.h
@@ -39,6 +39,11 @@
 
 class AsyncFileStorage;
 
+namespace Net
+{
+    struct DownloadResult;
+}
+
 namespace RSS
 {
     class Article;
@@ -85,9 +90,8 @@ namespace RSS
     private slots:
         void handleSessionProcessingEnabledChanged(bool enabled);
         void handleMaxArticlesPerFeedChanged(int n);
-        void handleIconDownloadFinished(const QString &url, const QString &filePath);
-        void handleDownloadFinished(const QString &url, const QByteArray &data);
-        void handleDownloadFailed(const QString &url, const QString &error);
+        void handleIconDownloadFinished(const Net::DownloadResult &result);
+        void handleDownloadFinished(const Net::DownloadResult &result);
         void handleParsingFinished(const Private::ParsingResult &result);
         void handleArticleRead(Article *article);
 
diff --git a/src/base/search/searchpluginmanager.cpp b/src/base/search/searchpluginmanager.cpp
index 3bfd4d4de..7d3d3bd7a 100644
--- a/src/base/search/searchpluginmanager.cpp
+++ b/src/base/search/searchpluginmanager.cpp
@@ -200,9 +200,7 @@ void SearchPluginManager::installPlugin(const QString &source)
     if (Net::DownloadManager::hasSupportedScheme(source)) {
         using namespace Net;
         DownloadHandler *handler = DownloadManager::instance()->download(DownloadRequest(source).saveToFile(true));
-        connect(handler, static_cast<void (DownloadHandler::*)(const QString &, const QString &)>(&DownloadHandler::downloadFinished)
-                , this, &SearchPluginManager::pluginDownloaded);
-        connect(handler, &DownloadHandler::downloadFailed, this, &SearchPluginManager::pluginDownloadFailed);
+        connect(handler, &Net::DownloadHandler::finished, this, &SearchPluginManager::pluginDownloadFinished);
     }
     else {
         QString path = source;
@@ -305,9 +303,7 @@ void SearchPluginManager::checkForUpdates()
     // Download version file from update server
     using namespace Net;
     DownloadHandler *handler = DownloadManager::instance()->download({m_updateUrl + "versions.txt"});
-    connect(handler, static_cast<void (DownloadHandler::*)(const QString &, const QByteArray &)>(&DownloadHandler::downloadFinished)
-            , this, &SearchPluginManager::versionInfoDownloaded);
-    connect(handler, &DownloadHandler::downloadFailed, this, &SearchPluginManager::versionInfoDownloadFailed);
+    connect(handler, &Net::DownloadHandler::finished, this, &SearchPluginManager::versionInfoDownloadFinished);
 }
 
 SearchDownloadHandler *SearchPluginManager::downloadTorrent(const QString &siteUrl, const QString &url)
@@ -364,36 +360,32 @@ QString SearchPluginManager::engineLocation()
     return location;
 }
 
-void SearchPluginManager::versionInfoDownloaded(const QString &url, const QByteArray &data)
+void SearchPluginManager::versionInfoDownloadFinished(const Net::DownloadResult &result)
 {
-    Q_UNUSED(url)
-    parseVersionInfo(data);
-}
-
-void SearchPluginManager::versionInfoDownloadFailed(const QString &url, const QString &reason)
-{
-    Q_UNUSED(url)
-    emit checkForUpdatesFailed(tr("Update server is temporarily unavailable. %1").arg(reason));
+    if (result.status == Net::DownloadStatus::Success)
+        parseVersionInfo(result.data);
+    else
+        emit checkForUpdatesFailed(tr("Update server is temporarily unavailable. %1").arg(result.errorString));
 }
 
-void SearchPluginManager::pluginDownloaded(const QString &url, QString filePath)
+void SearchPluginManager::pluginDownloadFinished(const Net::DownloadResult &result)
 {
-    filePath = Utils::Fs::fromNativePath(filePath);
-
-    QString pluginName = Utils::Fs::fileName(url);
-    pluginName.chop(pluginName.size() - pluginName.lastIndexOf('.')); // Remove extension
-    installPlugin_impl(pluginName, filePath);
-    Utils::Fs::forceRemove(filePath);
-}
+    if (result.status == Net::DownloadStatus::Success) {
+        const QString filePath = Utils::Fs::fromNativePath(result.filePath);
 
-void SearchPluginManager::pluginDownloadFailed(const QString &url, const QString &reason)
-{
-    QString pluginName = url.split('/').last();
-    pluginName.replace(".py", "", Qt::CaseInsensitive);
-    if (pluginInfo(pluginName))
-        emit pluginUpdateFailed(pluginName, tr("Failed to download the plugin file. %1").arg(reason));
-    else
-        emit pluginInstallationFailed(pluginName, tr("Failed to download the plugin file. %1").arg(reason));
+        QString pluginName = Utils::Fs::fileName(result.url);
+        pluginName.chop(pluginName.size() - pluginName.lastIndexOf('.')); // Remove extension
+        installPlugin_impl(pluginName, filePath);
+        Utils::Fs::forceRemove(filePath);
+    }
+    else {
+        QString pluginName = result.url.split('/').last();
+        pluginName.replace(".py", "", Qt::CaseInsensitive);
+        if (pluginInfo(pluginName))
+            emit pluginUpdateFailed(pluginName, tr("Failed to download the plugin file. %1").arg(result.errorString));
+        else
+            emit pluginInstallationFailed(pluginName, tr("Failed to download the plugin file. %1").arg(result.errorString));
+    }
 }
 
 // Update nova.py search plugin if necessary
diff --git a/src/base/search/searchpluginmanager.h b/src/base/search/searchpluginmanager.h
index ac485807d..60b32e8ff 100644
--- a/src/base/search/searchpluginmanager.h
+++ b/src/base/search/searchpluginmanager.h
@@ -38,6 +38,11 @@
 using PluginVersion = Utils::Version<unsigned short, 2>;
 Q_DECLARE_METATYPE(PluginVersion)
 
+namespace Net
+{
+    struct DownloadResult;
+}
+
 struct PluginInfo
 {
     QString name;
@@ -104,10 +109,8 @@ private:
     void installPlugin_impl(const QString &name, const QString &path);
     bool isUpdateNeeded(const QString &pluginName, PluginVersion newVersion) const;
 
-    void versionInfoDownloaded(const QString &url, const QByteArray &data);
-    void versionInfoDownloadFailed(const QString &url, const QString &reason);
-    void pluginDownloaded(const QString &url, QString filePath);
-    void pluginDownloadFailed(const QString &url, const QString &reason);
+    void versionInfoDownloadFinished(const Net::DownloadResult &result);
+    void pluginDownloadFinished(const Net::DownloadResult &result);
 
     static QString pluginPath(const QString &name);
 
diff --git a/src/gui/addnewtorrentdialog.cpp b/src/gui/addnewtorrentdialog.cpp
index 0a6d15f8d..d40da8c01 100644
--- a/src/gui/addnewtorrentdialog.cpp
+++ b/src/gui/addnewtorrentdialog.cpp
@@ -238,11 +238,8 @@ void AddNewTorrentDialog::show(const QString &source, const BitTorrent::AddTorre
     if (Net::DownloadManager::hasSupportedScheme(source)) {
         // Launch downloader
         Net::DownloadHandler *handler = Net::DownloadManager::instance()->download(
-                Net::DownloadRequest(source).limit(10485760 /* 10MB */).handleRedirectToMagnet(true));
-        connect(handler, static_cast<void (Net::DownloadHandler::*)(const QString &, const QByteArray &)>(&Net::DownloadHandler::downloadFinished)
-                , dlg, &AddNewTorrentDialog::handleDownloadFinished);
-        connect(handler, &Net::DownloadHandler::downloadFailed, dlg, &AddNewTorrentDialog::handleDownloadFailed);
-        connect(handler, &Net::DownloadHandler::redirectedToMagnet, dlg, &AddNewTorrentDialog::handleRedirectedToMagnet);
+                Net::DownloadRequest(source).limit(10485760 /* 10MB */));
+        connect(handler, &Net::DownloadHandler::finished, dlg, &AddNewTorrentDialog::handleDownloadFinished);
         return;
     }
 
@@ -761,39 +758,36 @@ void AddNewTorrentDialog::setupTreeview()
     showAdvancedSettings(settings()->loadValue(KEY_EXPANDED, false).toBool());
 }
 
-void AddNewTorrentDialog::handleDownloadFailed(const QString &url, const QString &reason)
-{
-    RaisedMessageBox::critical(this, tr("Download Error"),
-        QString("Cannot download '%1': %2").arg(url, reason));
-    this->deleteLater();
-}
-
-void AddNewTorrentDialog::handleRedirectedToMagnet(const QString &url, const QString &magnetUri)
-{
-    Q_UNUSED(url)
-
-    if (loadMagnet(BitTorrent::MagnetUri(magnetUri)))
-        open();
-    else
-        this->deleteLater();
-}
-
-void AddNewTorrentDialog::handleDownloadFinished(const QString &url, const QByteArray &data)
+void AddNewTorrentDialog::handleDownloadFinished(const Net::DownloadResult &result)
 {
     QString error;
-    m_torrentInfo = BitTorrent::TorrentInfo::load(data, &error);
-    if (!m_torrentInfo.isValid()) {
-        RaisedMessageBox::critical(this, tr("Invalid torrent"), tr("Failed to load from URL: %1.\nError: %2")
-            .arg(url, error));
-        return;
-    }
-
-    m_torrentGuard.reset(new TorrentFileGuard);
+    switch (result.status) {
+    case Net::DownloadStatus::Success:
+        m_torrentInfo = BitTorrent::TorrentInfo::load(result.data, &error);
+        if (!m_torrentInfo.isValid()) {
+            RaisedMessageBox::critical(this, tr("Invalid torrent"), tr("Failed to load from URL: %1.\nError: %2")
+                                       .arg(result.url, error));
+            return;
+        }
 
-    if (loadTorrentImpl())
-        open();
-    else
-        this->deleteLater();
+        m_torrentGuard.reset(new TorrentFileGuard);
+
+        if (loadTorrentImpl())
+            open();
+        else
+            deleteLater();
+        break;
+    case Net::DownloadStatus::RedirectedToMagnet:
+        if (loadMagnet(BitTorrent::MagnetUri(result.magnet)))
+            open();
+        else
+            deleteLater();
+        break;
+    default:
+        RaisedMessageBox::critical(this, tr("Download Error"),
+            tr("Cannot download '%1': %2").arg(result.url, result.errorString));
+        deleteLater();
+    }
 }
 
 void AddNewTorrentDialog::TMMChanged(int index)
diff --git a/src/gui/addnewtorrentdialog.h b/src/gui/addnewtorrentdialog.h
index dd9268f0b..49fe4279b 100644
--- a/src/gui/addnewtorrentdialog.h
+++ b/src/gui/addnewtorrentdialog.h
@@ -43,6 +43,11 @@ namespace BitTorrent
     class MagnetUri;
 }
 
+namespace Net
+{
+    struct DownloadResult;
+}
+
 namespace Ui
 {
     class AddNewTorrentDialog;
@@ -55,12 +60,13 @@ class TorrentFileGuard;
 class AddNewTorrentDialog : public QDialog
 {
     Q_OBJECT
+    Q_DISABLE_COPY(AddNewTorrentDialog)
 
 public:
     static const int minPathHistoryLength = 0;
     static const int maxPathHistoryLength = 99;
 
-    ~AddNewTorrentDialog();
+    ~AddNewTorrentDialog() override;
 
     static bool isEnabled();
     static void setEnabled(bool value);
@@ -79,9 +85,7 @@ private slots:
     void onSavePathChanged(const QString &newPath);
     void renameSelectedFile();
     void updateMetadata(const BitTorrent::TorrentInfo &info);
-    void handleDownloadFailed(const QString &url, const QString &reason);
-    void handleRedirectedToMagnet(const QString &url, const QString &magnetUri);
-    void handleDownloadFinished(const QString &url, const QByteArray &data);
+    void handleDownloadFinished(const Net::DownloadResult &result);
     void TMMChanged(int index);
     void categoryChanged(int index);
     void doNotDeleteTorrentClicked(bool checked);
diff --git a/src/gui/mainwindow.cpp b/src/gui/mainwindow.cpp
index e8b50e035..ed3e917f3 100644
--- a/src/gui/mainwindow.cpp
+++ b/src/gui/mainwindow.cpp
@@ -2020,26 +2020,31 @@ void MainWindow::installPython()
                                   : "https://www.python.org/ftp/python/3.4.4/python-3.4.4.msi");
     Net::DownloadHandler *handler = Net::DownloadManager::instance()->download(
                                         Net::DownloadRequest(installerURL).saveToFile(true));
-
-    using Func = void (Net::DownloadHandler::*)(const QString &, const QString &);
-    connect(handler, static_cast<Func>(&Net::DownloadHandler::downloadFinished), this, &MainWindow::pythonDownloadSuccess);
-    connect(handler, static_cast<Func>(&Net::DownloadHandler::downloadFailed), this, &MainWindow::pythonDownloadFailure);
+    connect(handler, &Net::DownloadHandler::finished, this, &MainWindow::pythonDownloadFinished);
 }
 
-void MainWindow::pythonDownloadSuccess(const QString &url, const QString &filePath)
+void MainWindow::pythonDownloadFinished(const Net::DownloadResult &result)
 {
-    Q_UNUSED(url)
+    if (result.status != Net::DownloadStatus::Success) {
+        setCursor(QCursor(Qt::ArrowCursor));
+        QMessageBox::warning(
+                    this, tr("Download error")
+                    , tr("Python setup could not be downloaded, reason: %1.\nPlease install it manually.")
+                    .arg(result.errorString));
+        return;
+    }
+
     setCursor(QCursor(Qt::ArrowCursor));
     QProcess installer;
     qDebug("Launching Python installer in passive mode...");
 
     if (QSysInfo::windowsVersion() >= QSysInfo::WV_VISTA) {
-        QFile::rename(filePath, filePath + ".exe");
-        installer.start('"' + Utils::Fs::toNativePath(filePath) + ".exe\" /passive");
+        QFile::rename(result.filePath, result.filePath + ".exe");
+        installer.start('"' + Utils::Fs::toNativePath(result.filePath) + ".exe\" /passive");
     }
     else {
-        QFile::rename(filePath, filePath + ".msi");
-        installer.start(Utils::Misc::windowsSystemPath() + "\\msiexec.exe /passive /i \"" + Utils::Fs::toNativePath(filePath) + ".msi\"");
+        QFile::rename(result.filePath, result.filePath + ".msi");
+        installer.start(Utils::Misc::windowsSystemPath() + "\\msiexec.exe /passive /i \"" + Utils::Fs::toNativePath(result.filePath) + ".msi\"");
     }
 
     // Wait for setup to complete
@@ -2050,21 +2055,13 @@ void MainWindow::pythonDownloadSuccess(const QString &url, const QString &filePa
     qDebug("Setup should be complete!");
     // Delete temp file
     if (QSysInfo::windowsVersion() >= QSysInfo::WV_VISTA)
-        Utils::Fs::forceRemove(filePath + ".exe");
+        Utils::Fs::forceRemove(result.filePath + ".exe");
     else
-        Utils::Fs::forceRemove(filePath + ".msi");
+        Utils::Fs::forceRemove(result.filePath + ".msi");
     // Reload search engine
     if (Utils::ForeignApps::pythonInfo().isSupportedVersion()) {
         m_ui->actionSearchWidget->setChecked(true);
         displaySearchTab(true);
     }
 }
-
-void MainWindow::pythonDownloadFailure(const QString &url, const QString &error)
-{
-    Q_UNUSED(url)
-    setCursor(QCursor(Qt::ArrowCursor));
-    QMessageBox::warning(this, tr("Download error"), tr("Python setup could not be downloaded, reason: %1.\nPlease install it manually.").arg(error));
-}
-
 #endif // Q_OS_WIN
diff --git a/src/gui/mainwindow.h b/src/gui/mainwindow.h
index f02983921..b11f82482 100644
--- a/src/gui/mainwindow.h
+++ b/src/gui/mainwindow.h
@@ -62,6 +62,11 @@ namespace BitTorrent
     class TorrentHandle;
 }
 
+namespace Net
+{
+    struct DownloadResult;
+}
+
 namespace Ui
 {
     class MainWindow;
@@ -135,8 +140,7 @@ private slots:
     void toggleAlternativeSpeeds();
 
 #ifdef Q_OS_WIN
-    void pythonDownloadSuccess(const QString &url, const QString &filePath);
-    void pythonDownloadFailure(const QString &url, const QString &error);
+    void pythonDownloadFinished(const Net::DownloadResult &result);
 #endif
     void addToolbarContextMenu();
     void manageCookies();
diff --git a/src/gui/programupdater.cpp b/src/gui/programupdater.cpp
index 4669c5ca6..46d84cd57 100644
--- a/src/gui/programupdater.cpp
+++ b/src/gui/programupdater.cpp
@@ -58,14 +58,18 @@ void ProgramUpdater::checkForUpdates()
     // the filehost can identify it and contact us.
     Net::DownloadHandler *handler = Net::DownloadManager::instance()->download(
                 Net::DownloadRequest(RSS_URL).userAgent("qBittorrent/" QBT_VERSION_2 " ProgramUpdater (www.qbittorrent.org)"));
-    connect(handler, static_cast<void (Net::DownloadHandler::*)(const QString &, const QByteArray &)>(&Net::DownloadHandler::downloadFinished)
-            , this, &ProgramUpdater::rssDownloadFinished);
-    connect(handler, &Net::DownloadHandler::downloadFailed, this, &ProgramUpdater::rssDownloadFailed);
+    connect(handler, &Net::DownloadHandler::finished, this, &ProgramUpdater::rssDownloadFinished);
 }
 
-void ProgramUpdater::rssDownloadFinished(const QString &url, const QByteArray &data)
+void ProgramUpdater::rssDownloadFinished(const Net::DownloadResult &result)
 {
-    Q_UNUSED(url);
+
+    if (result.status != Net::DownloadStatus::Success) {
+        qDebug() << "Downloading the new qBittorrent updates RSS failed:" << result.errorString;
+        emit updateCheckFinished(false, QString(), m_invokedByUser);
+        return;
+    }
+
     qDebug("Finished downloading the new qBittorrent updates RSS");
 
 #ifdef Q_OS_MAC
@@ -77,7 +81,7 @@ void ProgramUpdater::rssDownloadFinished(const QString &url, const QByteArray &d
 #endif
 
     QString version;
-    QXmlStreamReader xml(data);
+    QXmlStreamReader xml(result.data);
     bool inItem = false;
     QString updateLink;
     QString type;
@@ -118,14 +122,6 @@ void ProgramUpdater::rssDownloadFinished(const QString &url, const QByteArray &d
     emit updateCheckFinished(!m_updateUrl.isEmpty(), version, m_invokedByUser);
 }
 
-void ProgramUpdater::rssDownloadFailed(const QString &url, const QString &error)
-{
-    Q_UNUSED(url);
-
-    qDebug() << "Downloading the new qBittorrent updates RSS failed:" << error;
-    emit updateCheckFinished(false, QString(), m_invokedByUser);
-}
-
 void ProgramUpdater::updateProgram()
 {
     Q_ASSERT(!m_updateUrl.isEmpty());
diff --git a/src/gui/programupdater.h b/src/gui/programupdater.h
index 34b8e1762..f87836869 100644
--- a/src/gui/programupdater.h
+++ b/src/gui/programupdater.h
@@ -32,9 +32,15 @@
 #include <QObject>
 #include <QUrl>
 
+namespace Net
+{
+    struct DownloadResult;
+}
+
 class ProgramUpdater : public QObject
 {
     Q_OBJECT
+    Q_DISABLE_COPY(ProgramUpdater)
 
 public:
     explicit ProgramUpdater(QObject *parent = nullptr, bool invokedByUser = false);
@@ -46,8 +52,7 @@ signals:
     void updateCheckFinished(bool updateAvailable, QString version, bool invokedByUser);
 
 private slots:
-    void rssDownloadFinished(const QString &url, const QByteArray &data);
-    void rssDownloadFailed(const QString &url, const QString &error);
+    void rssDownloadFinished(const Net::DownloadResult &result);
 
 private:
     bool isVersionMoreRecent(const QString &remoteVersion) const;
diff --git a/src/gui/properties/trackersadditiondialog.cpp b/src/gui/properties/trackersadditiondialog.cpp
index c63628e86..bc1f23e79 100644
--- a/src/gui/properties/trackersadditiondialog.cpp
+++ b/src/gui/properties/trackersadditiondialog.cpp
@@ -72,15 +72,24 @@ void TrackersAdditionDialog::on_uTorrentListButton_clicked()
 {
     m_ui->uTorrentListButton->setEnabled(false);
     Net::DownloadHandler *handler = Net::DownloadManager::instance()->download(m_ui->lineEditListURL->text());
-    connect(handler, static_cast<void (Net::DownloadHandler::*)(const QString &, const QByteArray &)>(&Net::DownloadHandler::downloadFinished)
-            , this, &TrackersAdditionDialog::parseUTorrentList);
-    connect(handler, &Net::DownloadHandler::downloadFailed, this, &TrackersAdditionDialog::getTrackerError);
+    connect(handler, &Net::DownloadHandler::finished, this, &TrackersAdditionDialog::torrentListDownloadFinished);
     // Just to show that it takes times
     setCursor(Qt::WaitCursor);
 }
 
-void TrackersAdditionDialog::parseUTorrentList(const QString &, const QByteArray &data)
+void TrackersAdditionDialog::torrentListDownloadFinished(const Net::DownloadResult &result)
 {
+    if (result.status != Net::DownloadStatus::Success) {
+        // To restore the cursor ...
+        setCursor(Qt::ArrowCursor);
+        m_ui->uTorrentListButton->setEnabled(true);
+        QMessageBox::warning(
+                    this, tr("Download error")
+                    , tr("The trackers list could not be downloaded, reason: %1")
+                    .arg(result.errorString), QMessageBox::Ok);
+        return;
+    }
+
     // Load from torrent handle
     QList<BitTorrent::TrackerEntry> existingTrackers = m_torrent->trackers();
     // Load from current user list
@@ -96,7 +105,7 @@ void TrackersAdditionDialog::parseUTorrentList(const QString &, const QByteArray
         m_ui->textEditTrackersList->insertPlainText("\n");
     int nb = 0;
     QBuffer buffer;
-    buffer.setData(data);
+    buffer.setData(result.data);
     buffer.open(QBuffer::ReadOnly);
     while (!buffer.atEnd()) {
         const QString line = buffer.readLine().trimmed();
@@ -117,14 +126,6 @@ void TrackersAdditionDialog::parseUTorrentList(const QString &, const QByteArray
         QMessageBox::information(this, tr("No change"), tr("No additional trackers were found."), QMessageBox::Ok);
 }
 
-void TrackersAdditionDialog::getTrackerError(const QString &, const QString &error)
-{
-    // To restore the cursor ...
-    setCursor(Qt::ArrowCursor);
-    m_ui->uTorrentListButton->setEnabled(true);
-    QMessageBox::warning(this, tr("Download error"), tr("The trackers list could not be downloaded, reason: %1").arg(error), QMessageBox::Ok);
-}
-
 QStringList TrackersAdditionDialog::askForTrackers(QWidget *parent, BitTorrent::TorrentHandle *const torrent)
 {
     QStringList trackers;
diff --git a/src/gui/properties/trackersadditiondialog.h b/src/gui/properties/trackersadditiondialog.h
index c6843d340..29566079b 100644
--- a/src/gui/properties/trackersadditiondialog.h
+++ b/src/gui/properties/trackersadditiondialog.h
@@ -39,6 +39,11 @@ namespace BitTorrent
     class TorrentHandle;
 }
 
+namespace Net
+{
+    struct DownloadResult;
+}
+
 namespace Ui
 {
     class TrackersAdditionDialog;
@@ -57,8 +62,7 @@ public:
 
 public slots:
     void on_uTorrentListButton_clicked();
-    void parseUTorrentList(const QString &, const QByteArray &data);
-    void getTrackerError(const QString &, const QString &error);
+    void torrentListDownloadFinished(const Net::DownloadResult &result);
 
 private:
     Ui::TrackersAdditionDialog *m_ui;
diff --git a/src/gui/search/pluginselectdialog.cpp b/src/gui/search/pluginselectdialog.cpp
index 17666bd91..e67e9c89f 100644
--- a/src/gui/search/pluginselectdialog.cpp
+++ b/src/gui/search/pluginselectdialog.cpp
@@ -293,9 +293,7 @@ void PluginSelectDialog::addNewPlugin(const QString &pluginName)
         using namespace Net;
         DownloadHandler *handler = DownloadManager::instance()->download(
                     DownloadRequest(plugin->url + "/favicon.ico").saveToFile(true));
-        connect(handler, static_cast<void (DownloadHandler::*)(const QString &, const QString &)>(&DownloadHandler::downloadFinished)
-                , this, &PluginSelectDialog::iconDownloaded);
-        connect(handler, &DownloadHandler::downloadFailed, this, &PluginSelectDialog::iconDownloadFailed);
+        connect(handler, &DownloadHandler::finished, this, &PluginSelectDialog::iconDownloadFinished);
     }
     item->setText(PLUGIN_VERSION, plugin->version);
 }
@@ -369,9 +367,14 @@ void PluginSelectDialog::askForLocalPlugin()
     }
 }
 
-void PluginSelectDialog::iconDownloaded(const QString &url, QString filePath)
+void PluginSelectDialog::iconDownloadFinished(const Net::DownloadResult &result)
 {
-    filePath = Utils::Fs::fromNativePath(filePath);
+    if (result.status != Net::DownloadStatus::Success) {
+        qDebug("Could not download favicon: %s, reason: %s", qUtf8Printable(result.url), qUtf8Printable(result.errorString));
+        return;
+    }
+
+    const QString filePath = Utils::Fs::fromNativePath(result.filePath);
 
     // Icon downloaded
     QIcon icon(filePath);
@@ -379,7 +382,7 @@ void PluginSelectDialog::iconDownloaded(const QString &url, QString filePath)
     QList<QSize> sizes = icon.availableSizes();
     bool invalid = (sizes.isEmpty() || icon.pixmap(sizes.first()).isNull());
     if (!invalid) {
-        for (QTreeWidgetItem *item : asConst(findItemsWithUrl(url))) {
+        for (QTreeWidgetItem *item : asConst(findItemsWithUrl(result.url))) {
             QString id = item->text(PLUGIN_ID);
             PluginInfo *plugin = m_pluginManager->pluginInfo(id);
             if (!plugin) continue;
@@ -387,7 +390,7 @@ void PluginSelectDialog::iconDownloaded(const QString &url, QString filePath)
             QString iconPath = QString("%1/%2.%3")
                 .arg(SearchPluginManager::pluginsLocation()
                     , id
-                    , url.endsWith(".ico", Qt::CaseInsensitive) ? "ico" : "png");
+                    , result.url.endsWith(".ico", Qt::CaseInsensitive) ? "ico" : "png");
             if (QFile::copy(filePath, iconPath)) {
                 // This 2nd check is necessary. Some favicons (eg from piratebay)
                 // decode fine without an ext, but fail to do so when appending the ext
@@ -409,11 +412,6 @@ void PluginSelectDialog::iconDownloaded(const QString &url, QString filePath)
     Utils::Fs::forceRemove(filePath);
 }
 
-void PluginSelectDialog::iconDownloadFailed(const QString &url, const QString &reason)
-{
-    qDebug("Could not download favicon: %s, reason: %s", qUtf8Printable(url), qUtf8Printable(reason));
-}
-
 void PluginSelectDialog::checkForUpdatesFinished(const QHash<QString, PluginVersion> &updateInfo)
 {
     finishAsyncOp();
diff --git a/src/gui/search/pluginselectdialog.h b/src/gui/search/pluginselectdialog.h
index c2754f8bf..c8bf18c25 100644
--- a/src/gui/search/pluginselectdialog.h
+++ b/src/gui/search/pluginselectdialog.h
@@ -38,6 +38,11 @@ class QDropEvent;
 class QStringList;
 class QTreeWidgetItem;
 
+namespace Net
+{
+    struct DownloadResult;
+}
+
 namespace Ui
 {
     class PluginSelectDialog;
@@ -46,10 +51,11 @@ namespace Ui
 class PluginSelectDialog : public QDialog
 {
     Q_OBJECT
+    Q_DISABLE_COPY(PluginSelectDialog)
 
 public:
     explicit PluginSelectDialog(SearchPluginManager *pluginManager, QWidget *parent = nullptr);
-    ~PluginSelectDialog();
+    ~PluginSelectDialog() override;
 
     QList<QTreeWidgetItem*> findItemsWithUrl(const QString &url);
     QTreeWidgetItem *findItemWithID(const QString &id);
@@ -69,8 +75,7 @@ private slots:
     void enableSelection(bool enable);
     void askForLocalPlugin();
     void askForPluginUrl();
-    void iconDownloaded(const QString &url, QString filePath);
-    void iconDownloadFailed(const QString &url, const QString &reason);
+    void iconDownloadFinished(const Net::DownloadResult &result);
 
     void checkForUpdatesFinished(const QHash<QString, PluginVersion> &updateInfo);
     void checkForUpdatesFailed(const QString &reason);
diff --git a/src/gui/transferlistfilterswidget.cpp b/src/gui/transferlistfilterswidget.cpp
index 64f65d118..5e84f2568 100644
--- a/src/gui/transferlistfilterswidget.cpp
+++ b/src/gui/transferlistfilterswidget.cpp
@@ -408,47 +408,42 @@ void TrackerFiltersList::downloadFavicon(const QString &url)
     if (!m_downloadTrackerFavicon) return;
     Net::DownloadHandler *h = Net::DownloadManager::instance()->download(
                 Net::DownloadRequest(url).saveToFile(true));
-    using Func = void (Net::DownloadHandler::*)(const QString &, const QString &);
-    connect(h, static_cast<Func>(&Net::DownloadHandler::downloadFinished), this
-            , &TrackerFiltersList::handleFavicoDownload);
-    connect(h, static_cast<Func>(&Net::DownloadHandler::downloadFailed), this
-            , &TrackerFiltersList::handleFavicoFailure);
+    connect(h, &Net::DownloadHandler::finished, this, &TrackerFiltersList::handleFavicoDownloadFinished);
 }
 
-void TrackerFiltersList::handleFavicoDownload(const QString &url, const QString &filePath)
+void TrackerFiltersList::handleFavicoDownloadFinished(const Net::DownloadResult &result)
 {
-    const QString host = getHost(url);
+    if (result.status != Net::DownloadStatus::Success) {
+        if (result.url.endsWith(".ico", Qt::CaseInsensitive))
+            downloadFavicon(result.url.left(result.url.size() - 4) + ".png");
+        return;
+    }
+
+    const QString host = getHost(result.url);
 
     if (!m_trackers.contains(host)) {
-        Utils::Fs::forceRemove(filePath);
+        Utils::Fs::forceRemove(result.filePath);
         return;
     }
 
     QListWidgetItem *trackerItem = item(rowFromTracker(host));
     if (!trackerItem) return;
 
-    QIcon icon(filePath);
+    QIcon icon(result.filePath);
     //Detect a non-decodable icon
     QList<QSize> sizes = icon.availableSizes();
     bool invalid = (sizes.isEmpty() || icon.pixmap(sizes.first()).isNull());
     if (invalid) {
-        if (url.endsWith(".ico", Qt::CaseInsensitive))
-            downloadFavicon(url.left(url.size() - 4) + ".png");
-        Utils::Fs::forceRemove(filePath);
+        if (result.url.endsWith(".ico", Qt::CaseInsensitive))
+            downloadFavicon(result.url.left(result.url.size() - 4) + ".png");
+        Utils::Fs::forceRemove(result.filePath);
     }
     else {
-        trackerItem->setData(Qt::DecorationRole, QVariant(QIcon(filePath)));
-        m_iconPaths.append(filePath);
+        trackerItem->setData(Qt::DecorationRole, QVariant(QIcon(result.filePath)));
+        m_iconPaths.append(result.filePath);
     }
 }
 
-void TrackerFiltersList::handleFavicoFailure(const QString &url, const QString &error)
-{
-    Q_UNUSED(error)
-    if (url.endsWith(".ico", Qt::CaseInsensitive))
-        downloadFavicon(url.left(url.size() - 4) + ".png");
-}
-
 void TrackerFiltersList::showMenu(QPoint)
 {
     QMenu menu(this);
diff --git a/src/gui/transferlistfilterswidget.h b/src/gui/transferlistfilterswidget.h
index bbea12e7f..da5422905 100644
--- a/src/gui/transferlistfilterswidget.h
+++ b/src/gui/transferlistfilterswidget.h
@@ -42,9 +42,15 @@ namespace BitTorrent
     class TrackerEntry;
 }
 
+namespace Net
+{
+    struct DownloadResult;
+}
+
 class BaseFilterWidget : public QListWidget
 {
     Q_OBJECT
+    Q_DISABLE_COPY(BaseFilterWidget)
 
 public:
     BaseFilterWidget(QWidget *parent, TransferListWidget *transferList);
@@ -68,6 +74,7 @@ private slots:
 class StatusFilterWidget : public BaseFilterWidget
 {
     Q_OBJECT
+    Q_DISABLE_COPY(StatusFilterWidget)
 
 public:
     StatusFilterWidget(QWidget *parent, TransferListWidget *transferList);
@@ -88,6 +95,7 @@ private:
 class TrackerFiltersList : public BaseFilterWidget
 {
     Q_OBJECT
+    Q_DISABLE_COPY(TrackerFiltersList)
 
 public:
     TrackerFiltersList(QWidget *parent, TransferListWidget *transferList);
@@ -105,8 +113,7 @@ public slots:
     void trackerWarning(const QString &hash, const QString &tracker);
 
 private slots:
-    void handleFavicoDownload(const QString &url, const QString &filePath);
-    void handleFavicoFailure(const QString &url, const QString &error);
+    void handleFavicoDownloadFinished(const Net::DownloadResult &result);
 
 private:
     // These 4 methods are virtual slots in the base class.