Handle exception when torrent file cannot be exported

Both `lt::create_torrent` constructor and `lt::create_torrent::generate()`
can throw an exception so we need to handle it to prevent the app from crashing.

src/base/bittorrent/bencoderesumedatastorage.cpp

@@ -338,18 +338,24 @@ void BitTorrent::BencodeResumeDataStorage::Worker::store(const TorrentID &id, co
     if (torrentInfo)
     {
         const QString torrentFilepath = m_resumeDataDir.absoluteFilePath(QString::fromLatin1("%1.torrent").arg(id.toString()));
-        const lt::create_torrent torrentCreator = lt::create_torrent(*torrentInfo);
-        const lt::entry metadata = torrentCreator.generate();
         try
         {
+            const auto torrentCreator = lt::create_torrent(*torrentInfo);
+            const lt::entry metadata = torrentCreator.generate();
             writeEntryToFile(torrentFilepath, metadata);
         }
         catch (const RuntimeError &err)
         {
-            LogMsg(tr("Couldn't save torrent metadata to '%1'. Error: %2")
+            LogMsg(tr("Couldn't save torrent metadata to '%1'. Error: %2.")
                    .arg(torrentFilepath, err.message()), Log::CRITICAL);
             return;
         }
+        catch (const std::exception &err)
+        {
+            LogMsg(tr("Couldn't save torrent metadata to '%1'. Error: %2.")
+                   .arg(torrentFilepath, QString::fromLocal8Bit(err.what())), Log::CRITICAL);
+            return;
+        }
     }
 
     lt::entry data = lt::write_resume_data(p);
@@ -371,7 +377,7 @@ void BitTorrent::BencodeResumeDataStorage::Worker::store(const TorrentID &id, co
     }
     catch (const RuntimeError &err)
     {
-        LogMsg(tr("Couldn't save torrent resume data to '%1'. Error: %2")
+        LogMsg(tr("Couldn't save torrent resume data to '%1'. Error: %2.")
                .arg(resumeFilepath, err.message()), Log::CRITICAL);
     }
 }

src/base/bittorrent/dbresumedatastorage.cpp

@@ -459,9 +459,18 @@ void BitTorrent::DBResumeDataStorage::Worker::store(const TorrentID &id, const L
     const std::shared_ptr<lt::torrent_info> torrentInfo = std::move(p.ti);
     if (torrentInfo)
     {
-        const lt::create_torrent torrentCreator = lt::create_torrent(*torrentInfo);
-        const lt::entry metadata = torrentCreator.generate();
-        lt::bencode(std::back_inserter(bencodedMetadata), metadata);
+        try
+        {
+            const auto torrentCreator = lt::create_torrent(*torrentInfo);
+            const lt::entry metadata = torrentCreator.generate();
+            lt::bencode(std::back_inserter(bencodedMetadata), metadata);
+        }
+        catch (const std::exception &err)
+        {
+            LogMsg(tr("Couldn't save torrent metadata. Error: %1.")
+                   .arg(QString::fromLocal8Bit(err.what())), Log::CRITICAL);
+            return;
+        }
 
         columns.append(DB_COLUMN_METADATA);
     }

src/base/bittorrent/session.cpp

@@ -2321,7 +2321,7 @@ void Session::exportTorrentFile(const Torrent *torrent, TorrentExportFolder fold
         }
         catch (const RuntimeError &err)
         {
-            LogMsg(tr("Couldn't export torrent metadata file '%1'. Reason: %2")
+            LogMsg(tr("Couldn't export torrent metadata file '%1'. Reason: %2.")
                    .arg(newTorrentPath, err.message()), Log::WARNING);
         }
     }

src/base/bittorrent/torrentcreatorthread.cpp

@@ -98,6 +98,12 @@ void TorrentCreatorThread::sendProgressSignal(int currentPieceIdx, int totalPiec
     emit updateProgress(static_cast<int>((currentPieceIdx * 100.) / totalPieces));
 }
 
+void TorrentCreatorThread::checkInterruptionRequested() const
+{
+    if (isInterruptionRequested())
+        throw RuntimeError(tr("Operation aborted"));
+}
+
 void TorrentCreatorThread::run()
 {
     emit updateProgress(0);
@@ -118,7 +124,7 @@ void TorrentCreatorThread::run()
             // need to sort the file names by natural sort order
             QStringList dirs = {m_params.inputPath};
 
-            QDirIterator dirIter(m_params.inputPath, (QDir::AllDirs | QDir::NoDotAndDotDot), QDirIterator::Subdirectories);
+            QDirIterator dirIter {m_params.inputPath, (QDir::AllDirs | QDir::NoDotAndDotDot), QDirIterator::Subdirectories};
             while (dirIter.hasNext())
             {
                 dirIter.next();
@@ -151,7 +157,7 @@ void TorrentCreatorThread::run()
                 fs.add_file(fileName.toStdString(), fileSizeMap[fileName]);
         }
 
-        if (isInterruptionRequested()) return;
+        checkInterruptionRequested();
 
 #if (LIBTORRENT_VERSION_NUM >= 20000)
         lt::create_torrent newTorrent {fs, m_params.pieceSize, toNativeTorrentFormatFlag(m_params.torrentFormat)};
@@ -181,9 +187,7 @@ void TorrentCreatorThread::run()
         lt::set_piece_hashes(newTorrent, Utils::Fs::toNativePath(parentPath).toStdString()
             , [this, &newTorrent](const lt::piece_index_t n)
         {
-            if (isInterruptionRequested())
-                throw RuntimeError {tr("Create new torrent aborted.")};
-
+            checkInterruptionRequested();
             sendProgressSignal(static_cast<LTUnderlyingType<lt::piece_index_t>>(n), newTorrent.num_pieces());
         });
 
@@ -194,7 +198,7 @@ void TorrentCreatorThread::run()
         // Is private ?
         newTorrent.set_priv(m_params.isPrivate);
 
-        if (isInterruptionRequested()) return;
+        checkInterruptionRequested();
 
         lt::entry entry = newTorrent.generate();
 
@@ -202,32 +206,30 @@ void TorrentCreatorThread::run()
         if (!m_params.source.isEmpty())
             entry["info"]["source"] = m_params.source.toStdString();
 
-        if (isInterruptionRequested()) return;
+        checkInterruptionRequested();
 
         // create the torrent
         QFile outfile {m_params.savePath};
         if (!outfile.open(QIODevice::WriteOnly))
-        {
-            throw RuntimeError {tr("Create new torrent file failed. Reason: %1")
-                .arg(outfile.errorString())};
-        }
+            throw RuntimeError(outfile.errorString());
 
-        if (isInterruptionRequested()) return;
+        checkInterruptionRequested();
 
         lt::bencode(Utils::IO::FileDeviceOutputIterator {outfile}, entry);
         if (outfile.error() != QFileDevice::NoError)
-        {
-            throw RuntimeError {tr("Create new torrent file failed. Reason: %1")
-                .arg(outfile.errorString())};
-        }
+            throw RuntimeError(outfile.errorString());
         outfile.close();
 
         emit updateProgress(100);
         emit creationSuccess(m_params.savePath, parentPath);
     }
-    catch (const std::exception &e)
+    catch (const RuntimeError &err)
+    {
+        emit creationFailure(tr("Create new torrent file failed. Reason: %1.").arg(err.message()));
+    }
+    catch (const std::exception &err)
     {
-        emit creationFailure(e.what());
+        emit creationFailure(tr("Create new torrent file failed. Reason: %1.").arg(QString::fromLocal8Bit(err.what())));
     }
 }
 

src/base/bittorrent/torrentcreatorthread.h

@@ -65,10 +65,11 @@ namespace BitTorrent
     class TorrentCreatorThread final : public QThread
     {
         Q_OBJECT
+        Q_DISABLE_COPY_MOVE(TorrentCreatorThread)
 
     public:
-        TorrentCreatorThread(QObject *parent = nullptr);
-        ~TorrentCreatorThread();
+        explicit TorrentCreatorThread(QObject *parent = nullptr);
+        ~TorrentCreatorThread() override;
 
         void create(const TorrentCreatorParams &params);
 
@@ -79,16 +80,15 @@ namespace BitTorrent
             , const int pieceSize, const bool isAlignmentOptimized, int paddedFileSizeLimit);
 #endif
 
-    protected:
-        void run() override;
-
     signals:
         void creationFailure(const QString &msg);
         void creationSuccess(const QString &path, const QString &branchPath);
         void updateProgress(int progress);
 
     private:
+        void run() override;
         void sendProgressSignal(int currentPieceIdx, int totalPieces);
+        void checkInterruptionRequested() const;
 
         TorrentCreatorParams m_params;
     };

src/base/bittorrent/torrentinfo.cpp

@@ -167,18 +167,25 @@ TorrentInfo TorrentInfo::loadFromFile(const QString &path, QString *error) noexc
 void TorrentInfo::saveToFile(const QString &path) const
 {
     if (!isValid())
-        throw RuntimeError {tr("Invalid metadata.")};
+        throw RuntimeError {tr("Invalid metadata")};
 
-    const lt::create_torrent torrentCreator = lt::create_torrent(*(nativeInfo()));
-    const lt::entry torrentEntry = torrentCreator.generate();
+    try
+    {
+        const auto torrentCreator = lt::create_torrent(*nativeInfo());
+        const lt::entry torrentEntry = torrentCreator.generate();
 
-    QFile torrentFile {path};
-    if (!torrentFile.open(QIODevice::WriteOnly))
-        throw RuntimeError {torrentFile.errorString()};
+        QFile torrentFile {path};
+        if (!torrentFile.open(QIODevice::WriteOnly))
+            throw RuntimeError(torrentFile.errorString());
 
-    lt::bencode(Utils::IO::FileDeviceOutputIterator {torrentFile}, torrentEntry);
-    if (torrentFile.error() != QFileDevice::NoError)
-        throw RuntimeError {torrentFile.errorString()};
+        lt::bencode(Utils::IO::FileDeviceOutputIterator {torrentFile}, torrentEntry);
+        if (torrentFile.error() != QFileDevice::NoError)
+            throw RuntimeError(torrentFile.errorString());
+    }
+    catch (const lt::system_error &err)
+    {
+        throw RuntimeError(QString::fromLocal8Bit(err.what()));
+    }
 }
 
 bool TorrentInfo::isValid() const

src/gui/addnewtorrentdialog.cpp

@@ -475,7 +475,8 @@ void AddNewTorrentDialog::saveTorrentFile()
     }
     catch (const RuntimeError &err)
     {
-        QMessageBox::critical(this, tr("I/O Error"), err.message());
+        QMessageBox::critical(this, tr("I/O Error")
+            , tr("Couldn't export torrent metadata file '%1'. Reason: %2.").arg(path, err.message()));
     }
 }