Auto-set a torrent's parameters based on metadata

Adds a system for configuring a set of rules that modify torrent
parameters based on the torrent's metadata. Rules are specified
via a JSON file loaded on startup.

Closes qbittorrent#5779.

src/base/CMakeLists.txt

@@ -43,6 +43,7 @@ add_library(qbt_base STATIC
     bittorrent/torrentdescriptor.h
     bittorrent/torrentimpl.h
     bittorrent/torrentinfo.h
+    bittorrent/torrentparamrules.h
     bittorrent/tracker.h
     bittorrent/trackerentry.h
     concepts/explicitlyconvertibleto.h
@@ -148,6 +149,7 @@ add_library(qbt_base STATIC
     bittorrent/torrentdescriptor.cpp
     bittorrent/torrentimpl.cpp
     bittorrent/torrentinfo.cpp
+    bittorrent/torrentparamrules.cpp
     bittorrent/tracker.cpp
     bittorrent/trackerentry.cpp
     exceptions.cpp

src/base/addtorrentmanager.cpp

@@ -32,6 +32,7 @@
 #include "base/bittorrent/infohash.h"
 #include "base/bittorrent/session.h"
 #include "base/bittorrent/torrentdescriptor.h"
+#include "base/bittorrent/torrentparamrules.h"
 #include "base/logger.h"
 #include "base/net/downloadmanager.h"
 #include "base/preferences.h"
@@ -177,15 +178,15 @@ void AddTorrentManager::releaseTorrentFileGuard(const QString &source)
 }
 
 bool AddTorrentManager::processTorrent(const QString &source, const BitTorrent::TorrentDescriptor &torrentDescr
-        , const BitTorrent::AddTorrentParams &addTorrentParams)
+        , BitTorrent::AddTorrentParams addTorrentParams)
 {
     const BitTorrent::InfoHash infoHash = torrentDescr.infoHash();
 
+    const bool hasMetadata = torrentDescr.info().has_value();
     if (BitTorrent::Torrent *torrent = btSession()->findTorrent(infoHash))
     {
         // a duplicate torrent is being added
 
-        const bool hasMetadata = torrentDescr.info().has_value();
         if (hasMetadata)
         {
             // Trying to set metadata to existing torrent in case if it has none
@@ -213,5 +214,9 @@ bool AddTorrentManager::processTorrent(const QString &source, const BitTorrent::
         return false;
     }
 
+    // If metadata is not available now, rules will be applied after it is downloaded.
+    if (hasMetadata)
+        btSession()->applyTorrentParamRules(torrentDescr, &addTorrentParams);
+
     return addTorrentToSession(source, torrentDescr, addTorrentParams);
 }

src/base/addtorrentmanager.h

@@ -81,7 +81,7 @@ class AddTorrentManager : public ApplicationComponent<QObject>
     void onSessionTorrentAdded(BitTorrent::Torrent *torrent);
     void onSessionAddTorrentFailed(const BitTorrent::InfoHash &infoHash, const QString &reason);
     bool processTorrent(const QString &source, const BitTorrent::TorrentDescriptor &torrentDescr
-            , const BitTorrent::AddTorrentParams &addTorrentParams);
+            , BitTorrent::AddTorrentParams addTorrentParams);
 
     BitTorrent::Session *m_btSession = nullptr;
     QHash<QString, BitTorrent::AddTorrentParams> m_downloadedTorrents;

src/base/bittorrent/session.h

@@ -32,6 +32,7 @@
 #include <QtContainerFwd>
 #include <QObject>
 
+#include "base/bittorrent/torrentparamrules.h"
 #include "base/pathfwd.h"
 #include "base/tagset.h"
 #include "addtorrentparams.h"
@@ -452,6 +453,7 @@ namespace BitTorrent
         virtual void banIP(const QString &ip) = 0;
 
         virtual bool isKnownTorrent(const InfoHash &infoHash) const = 0;
+        virtual void applyTorrentParamRules(const TorrentDescriptor &torrentDescr, AddTorrentParams *params) const = 0;
         virtual bool addTorrent(const TorrentDescriptor &torrentDescr, const AddTorrentParams &params = {}) = 0;
         virtual bool deleteTorrent(const TorrentID &id, DeleteOption deleteOption = DeleteOption::DeleteTorrent) = 0;
         virtual bool downloadMetadata(const TorrentDescriptor &torrentDescr) = 0;

src/base/bittorrent/sessionimpl.cpp

@@ -107,6 +107,7 @@ using namespace std::chrono_literals;
 using namespace BitTorrent;
 
 const Path CATEGORIES_FILE_NAME {u"categories.json"_s};
+const Path TORRENT_PARAM_RULES_FILE_NAME {u"auto_torrent_customizer_rules.json"_s};
 const int MAX_PROCESSING_RESUMEDATA_COUNT = 50;
 const int STATISTICS_SAVE_INTERVAL = std::chrono::milliseconds(15min).count();
 
@@ -580,6 +581,9 @@ SessionImpl::SessionImpl(QObject *parent)
     connect(m_ioThread.get(), &QThread::finished, m_fileSearcher, &QObject::deleteLater);
     connect(m_fileSearcher, &FileSearcher::searchFinished, this, &SessionImpl::fileSearchFinished);
 
+    m_torrentParamRules = new TorrentParamRules(this);
+    loadTorrentParamRules();
+
     m_ioThread->start();
 
     initMetrics();
@@ -4842,6 +4846,11 @@ void SessionImpl::setMaxRatioAction(const MaxRatioAction act)
     m_maxRatioAction = static_cast<int>(act);
 }
 
+void SessionImpl::applyTorrentParamRules(const TorrentDescriptor &torrentDescr, AddTorrentParams *params) const
+{
+    m_torrentParamRules->apply(torrentDescr, params);
+}
+
 bool SessionImpl::isKnownTorrent(const InfoHash &infoHash) const
 {
     const bool isHybrid = infoHash.isHybrid();
@@ -4939,6 +4948,8 @@ void SessionImpl::handleTorrentUrlSeedsRemoved(TorrentImpl *const torrent, const
 
 void SessionImpl::handleTorrentMetadataReceived(TorrentImpl *const torrent)
 {
+    qDebug() << "Metadata received for " << torrent->name();
+    m_torrentParamRules->apply(torrent);
     if (!torrentExportDirectory().isEmpty())
         exportTorrentFile(torrent, torrentExportDirectory());
 
@@ -5200,6 +5211,45 @@ void SessionImpl::loadCategories()
     }
 }
 
+void SessionImpl::loadTorrentParamRules()
+{
+    const Path path = specialFolderLocation(SpecialFolder::Config) / TORRENT_PARAM_RULES_FILE_NAME;
+    const QString pathStr = path.toString();
+    if (!path.exists())
+    {
+        LogMsg(tr("Auto torrent customizer rules not found at \"%1\"").arg(pathStr), Log::INFO);
+        return;
+    }
+
+    constexpr int fileMaxSize = 1024 * 1024;
+    const auto readResult = Utils::IO::readFile(path, fileMaxSize);
+    if (!readResult)
+    {
+        LogMsg(tr("Failed to read auto torrent customizer rules file \"%1\"").arg(readResult.error().message), Log::WARNING);
+        return;
+    }
+
+    QJsonParseError jsonError;
+    const auto jsonDoc = QJsonDocument::fromJson(readResult.value(), &jsonError);
+    if (jsonError.error != QJsonParseError::NoError)
+    {
+        LogMsg(tr("Failed to parse auto torrent customizer rules file: \"%1\". Error: \"%2\"")
+               .arg(pathStr, jsonError.errorString()), Log::WARNING);
+        return;
+    }
+
+    if (!jsonDoc.isObject())
+    {
+        LogMsg(tr("Failed to load auto torrent customizer rules from \"%1\". Error: \"Invalid data format\"")
+               .arg(pathStr), Log::WARNING);
+        return;
+    }
+
+    m_torrentParamRules->clearRules();
+    const size_t numRules = m_torrentParamRules->loadRulesFromJson(jsonDoc.object());
+    LogMsg(tr("Loaded %1 auto torrent customizer rule(s) from \"%2\"", nullptr, numRules).arg(numRules).arg(pathStr), Log::INFO);
+}
+
 bool SessionImpl::hasPerTorrentRatioLimit() const
 {
     return std::any_of(m_torrents.cbegin(), m_torrents.cend(), [](const TorrentImpl *torrent)

src/base/bittorrent/sessionimpl.h

@@ -419,6 +419,7 @@ namespace BitTorrent
         void banIP(const QString &ip) override;
 
         bool isKnownTorrent(const InfoHash &infoHash) const override;
+        void applyTorrentParamRules(const TorrentDescriptor &torrentDescr, AddTorrentParams *params) const override;
         bool addTorrent(const TorrentDescriptor &torrentDescr, const AddTorrentParams &params = {}) override;
         bool deleteTorrent(const TorrentID &id, DeleteOption deleteOption = DeleteTorrent) override;
         bool downloadMetadata(const TorrentDescriptor &torrentDescr) override;
@@ -584,6 +585,8 @@ namespace BitTorrent
         void upgradeCategories();
         DownloadPathOption resolveCategoryDownloadPathOption(const QString &categoryName, const std::optional<DownloadPathOption> &option) const;
 
+        void loadTorrentParamRules();
+
         void saveStatistics() const;
         void loadStatistics();
 
@@ -753,6 +756,7 @@ namespace BitTorrent
         QThreadPool *m_asyncWorker = nullptr;
         ResumeDataStorage *m_resumeDataStorage = nullptr;
         FileSearcher *m_fileSearcher = nullptr;
+        TorrentParamRules *m_torrentParamRules = nullptr;
 
         QHash<TorrentID, lt::torrent_handle> m_downloadedMetadata;