Use the incomplete folder where appropriate

Restored torrents already have the correct path saved in their fastresume. Don't override it.
Magnets and new torrents have to be set explicitly to the incomplete folder if it is enabled.

Closes #11552

src/base/bittorrent/session.cpp

@@ -1969,6 +1969,7 @@ bool Session::addTorrent(const TorrentInfo &torrentInfo, const AddTorrentParams
 bool Session::addTorrent_impl(CreateTorrentParams params, const MagnetUri &magnetUri,
                               TorrentInfo torrentInfo, const QByteArray &fastresumeData)
 {
+#if (LIBTORRENT_VERSION_NUM < 10200)
     params.savePath = normalizeSavePath(params.savePath, "");
 
     if (!params.category.isEmpty()) {
@@ -2000,12 +2001,9 @@ bool Session::addTorrent_impl(CreateTorrentParams params, const MagnetUri &magne
             lt::torrent_handle handle = m_nativeSession->find_torrent(hash);
             // We need to pause it first to create TorrentHandle within the same
             // underlying state as in other cases.
-#if (LIBTORRENT_VERSION_NUM < 10200)
             handle.auto_managed(false);
-#else
-            handle.unset_flags(lt::torrent_flags::auto_managed);
-#endif
             handle.pause();
+            // createTorrentHandle() for this is called in the torrent_paused_alert handler
 
             m_loadedMetadata.remove(hash);
             m_addingTorrents.insert(hash, params);
@@ -2013,6 +2011,14 @@ bool Session::addTorrent_impl(CreateTorrentParams params, const MagnetUri &magne
         }
 
         p = magnetUri.addTorrentParams();
+        if (isTempPathEnabled()) {
+            p.save_path = Utils::Fs::toNativePath(tempPath()).toStdString();
+        }
+        else {
+            // If empty then Automatic mode, otherwise Manual mode
+            const QString savePath = params.savePath.isEmpty() ? categorySavePath(params.category) : params.savePath;
+            p.save_path = Utils::Fs::toNativePath(savePath).toStdString();
+        }
     }
     else {
         if (!torrentInfo.isValid()) {
@@ -2041,13 +2047,8 @@ bool Session::addTorrent_impl(CreateTorrentParams params, const MagnetUri &magne
         return true;
     }
 
-    // Record if .fastresume is complete, that is whether it contains
-    // the required fields to resume a torrent.
-    bool hasCompleteFastresume = false;
-
     if (!fromMagnetUri) {
         if (params.restored) {  // load from existing fastresume
-#if (LIBTORRENT_VERSION_NUM < 10200)
             // Make sure the torrent will be initially checked and then paused
             // to perform some service jobs on it. We will start it if needed.
             // (Workaround to easily support libtorrent-1.1
@@ -2058,27 +2059,17 @@ bool Session::addTorrent_impl(CreateTorrentParams params, const MagnetUri &magne
             p.resume_data = std::vector<char> {patchedFastresumeData.constData()
                 , (patchedFastresumeData.constData() + patchedFastresumeData.size())};
             p.flags |= lt::add_torrent_params::flag_use_resume_save_path;
-
-            // Still setup the default parameters and let libtorrent handle
-            // the parameter merging
-            hasCompleteFastresume = false;
-#else
-            lt::error_code ec;
-            p = lt::read_resume_data(fastresumeData, ec);
-
-            // libtorrent will always apply `file_priorities` to torrents,
-            // if the field is present then the fastresume is considered to
-            // be correctly generated and should be complete.
-            hasCompleteFastresume = !p.file_priorities.empty();
-#endif
         }
         else {  // new torrent
             if (!params.hasRootFolder)
                 torrentInfo.stripRootFolder();
 
+            // If empty then Automatic mode, otherwise Manual mode
+            QString savePath = params.savePath.isEmpty() ? categorySavePath(params.category) : params.savePath;
             // Metadata
             if (!params.hasSeedStatus)
-                findIncompleteFiles(torrentInfo, savePath);
+                findIncompleteFiles(torrentInfo, savePath); // if needed points savePath to incomplete folder too
+            p.save_path = Utils::Fs::toNativePath(savePath).toStdString();
 
             // if torrent name wasn't explicitly set we handle the case of
             // initial renaming of torrent content and rename torrent accordingly
@@ -2095,12 +2086,7 @@ bool Session::addTorrent_impl(CreateTorrentParams params, const MagnetUri &magne
             std::transform(params.filePriorities.cbegin(), params.filePriorities.cend()
                            , std::back_inserter(p.file_priorities), [](const DownloadPriority priority)
             {
-#if (LIBTORRENT_VERSION_NUM < 10200)
                 return static_cast<boost::uint8_t>(priority);
-#else
-                return static_cast<lt::download_priority_t>(
-                            static_cast<lt::download_priority_t::underlying_type>(priority));
-#endif
             });
         }
 
@@ -2108,63 +2094,184 @@ bool Session::addTorrent_impl(CreateTorrentParams params, const MagnetUri &magne
     }
 
     // Common
-#if (LIBTORRENT_VERSION_NUM < 10200)
     p.flags &= ~lt::add_torrent_params::flag_duplicate_is_error; // Already checked
-#else
-    p.flags &= ~lt::torrent_flags::duplicate_is_error; // Already checked
-#endif
     // Make sure the torrent will be initially checked and then paused
     // to perform some service jobs on it. We will start it if needed.
-#if (LIBTORRENT_VERSION_NUM < 10200)
     p.flags |= lt::add_torrent_params::flag_paused;
     p.flags |= lt::add_torrent_params::flag_auto_managed;
     p.flags |= lt::add_torrent_params::flag_stop_when_ready;
+    // Limits
+    p.max_connections = maxConnectionsPerTorrent();
+    p.max_uploads = maxUploadsPerTorrent();
+    p.upload_limit = params.uploadLimit;
+    p.download_limit = params.downloadLimit;
+    // Preallocation mode
+    p.storage_mode = isPreallocationEnabled()
+                     ? lt::storage_mode_allocate : lt::storage_mode_sparse;
+
+    // Seeding mode
+    // Skip checking and directly start seeding
+    if (params.skipChecking)
+        p.flags |= lt::add_torrent_params::flag_seed_mode;
+    else
+        p.flags &= ~lt::add_torrent_params::flag_seed_mode;
+
+    m_addingTorrents.insert(hash, params);
+    // Adding torrent to BitTorrent session
+    m_nativeSession->async_add_torrent(p);
+
+    return true;
 #else
-    p.flags |= lt::torrent_flags::paused;
-    p.flags |= lt::torrent_flags::auto_managed;
-    p.flags |= lt::torrent_flags::stop_when_ready;
-#endif
+    params.savePath = normalizeSavePath(params.savePath, "");
 
-    if (!hasCompleteFastresume) {
-        // Limits
-        p.max_connections = maxConnectionsPerTorrent();
-        p.max_uploads = maxUploadsPerTorrent();
-        p.save_path = Utils::Fs::toNativePath(savePath).toStdString();
+    if (!params.category.isEmpty()) {
+        if (!m_categories.contains(params.category) && !addCategory(params.category))
+            params.category = "";
+    }
+
+    const bool fromMagnetUri = magnetUri.isValid();
+    lt::add_torrent_params p;
+    InfoHash hash;
+
+    if (fromMagnetUri) {
+        hash = magnetUri.hash();
+
+        const auto it = m_loadedMetadata.constFind(hash);
+        if (it != m_loadedMetadata.constEnd()) {
+            // Adding preloaded torrent...
+            const TorrentInfo metadata = it.value();
+            if (metadata.isValid()) {
+                // Metadata is received and torrent_handle is being deleted
+                // so we can't reuse it. Just add torrent using its metadata.
+                return addTorrent_impl(params
+                    , MagnetUri {}, metadata, fastresumeData);
+            }
+
+            // Reuse existing torrent_handle
+            lt::torrent_handle handle = m_nativeSession->find_torrent(hash);
+            // We need to pause it first to create TorrentHandle within the same
+            // underlying state as in other cases.
+            handle.unset_flags(lt::torrent_flags::auto_managed);
+            handle.pause();
+            // createTorrentHandle() for this is called in the torrent_paused_alert handler
+
+            m_loadedMetadata.remove(hash);
+            m_addingTorrents.insert(hash, params);
+            return true;
+        }
+
+        p = magnetUri.addTorrentParams();
+        if (isTempPathEnabled()) {
+            p.save_path = Utils::Fs::toNativePath(tempPath()).toStdString();
+        }
+        else {
+            // If empty then Automatic mode, otherwise Manual mode
+            const QString savePath = params.savePath.isEmpty() ? categorySavePath(params.category) : params.savePath;
+            p.save_path = Utils::Fs::toNativePath(savePath).toStdString();
+        }
+    }
+    else {
+        if (!torrentInfo.isValid()) {
+            // We can have an invalid torrentInfo when there isn't a matching
+            // .torrent file to the .fastresume we loaded. Possibly from a
+            // failed upgrade.
+            return false;
+        }
+
+        hash = torrentInfo.hash();
+    }
+
+    // We should not add the torrent if it is already
+    // processed or is pending to add to session
+    if (m_addingTorrents.contains(hash) || m_loadedMetadata.contains(hash))
+        return false;
+
+    TorrentHandle *const torrent = m_torrents.value(hash);
+    if (torrent) {  // a duplicate torrent is added
+        if (torrent->isPrivate() || (!fromMagnetUri && torrentInfo.isPrivate()))
+            return false;
+
+        // merge trackers and web seeds
+        torrent->addTrackers(fromMagnetUri ? magnetUri.trackers() : torrentInfo.trackers());
+        torrent->addUrlSeeds(fromMagnetUri ? magnetUri.urlSeeds() : torrentInfo.urlSeeds());
+        return true;
+    }
+
+    if (!fromMagnetUri) {
+        if (params.restored) {  // load from existing fastresume
+            lt::error_code ec;
+            p = lt::read_resume_data(fastresumeData, ec);
+        }
+        else {  // new torrent
+            if (!params.hasRootFolder)
+                torrentInfo.stripRootFolder();
+
+            // If empty then Automatic mode, otherwise Manual mode
+            QString savePath = params.savePath.isEmpty() ? categorySavePath(params.category) : params.savePath;
+            // Metadata
+            if (!params.hasSeedStatus)
+                findIncompleteFiles(torrentInfo, savePath); // if needed points savePath to incomplete folder too
+            p.save_path = Utils::Fs::toNativePath(savePath).toStdString();
+
+            // if torrent name wasn't explicitly set we handle the case of
+            // initial renaming of torrent content and rename torrent accordingly
+            if (params.name.isEmpty()) {
+                QString contentName = torrentInfo.rootFolder();
+                if (contentName.isEmpty() && (torrentInfo.filesCount() == 1))
+                    contentName = torrentInfo.fileName(0);
+
+                if (!contentName.isEmpty() && (contentName != torrentInfo.name()))
+                    params.name = contentName;
+            }
+
+            Q_ASSERT(p.file_priorities.empty());
+            std::transform(params.filePriorities.cbegin(), params.filePriorities.cend()
+                           , std::back_inserter(p.file_priorities), [](const DownloadPriority priority)
+            {
+                return static_cast<lt::download_priority_t>(
+                            static_cast<lt::download_priority_t::underlying_type>(priority));
+            });
+        }
+
+        p.ti = torrentInfo.nativeInfo();
+    }
+
+    if (fromMagnetUri && params.restored && params.addedTime.isValid())
+        p.added_time = params.addedTime.toSecsSinceEpoch();
+
+    if (fromMagnetUri || !params.restored) {
         p.upload_limit = params.uploadLimit;
         p.download_limit = params.downloadLimit;
 
-#if (LIBTORRENT_VERSION_NUM >= 10200)
-        if (params.addedTime.isValid())
-            p.added_time = params.addedTime.toSecsSinceEpoch();
-#endif
-
         // Preallocation mode
         p.storage_mode = isPreallocationEnabled()
             ? lt::storage_mode_allocate : lt::storage_mode_sparse;
 
         // Seeding mode
         // Skip checking and directly start seeding
-        if (params.skipChecking) {
-#if (LIBTORRENT_VERSION_NUM < 10200)
-            p.flags |= lt::add_torrent_params::flag_seed_mode;
-#else
+        if (params.skipChecking)
             p.flags |= lt::torrent_flags::seed_mode;
-#endif
-        }
-        else {
-#if (LIBTORRENT_VERSION_NUM < 10200)
-            p.flags &= ~lt::add_torrent_params::flag_seed_mode;
-#else
+        else
             p.flags &= ~lt::torrent_flags::seed_mode;
-#endif
-        }
     }
 
+    // Common
+    p.flags &= ~lt::torrent_flags::duplicate_is_error; // Already checked
+    // Make sure the torrent will be initially checked and then paused
+    // to perform some service jobs on it. We will start it if needed.
+    p.flags |= lt::torrent_flags::paused;
+    p.flags |= lt::torrent_flags::auto_managed;
+    p.flags |= lt::torrent_flags::stop_when_ready;
+    // Limits
+    p.max_connections = maxConnectionsPerTorrent();
+    p.max_uploads = maxUploadsPerTorrent();
+
     m_addingTorrents.insert(hash, params);
     // Adding torrent to BitTorrent session
     m_nativeSession->async_add_torrent(p);
 
     return true;
+#endif
 }
 
 bool Session::findIncompleteFiles(TorrentInfo &torrentInfo, QString &savePath) const