Add torrent for preloading magnet asynchronously

src/base/bittorrent/sessionimpl.cpp

@@ -2832,21 +2832,8 @@ bool SessionImpl::downloadMetadata(const MagnetUri &magnetUri)
 #endif
 
     // Adding torrent to libtorrent session
-    lt::error_code ec;
-    lt::torrent_handle torrentHandle = m_nativeSession->add_torrent(p, ec);
-    if (ec)
-        return false;
-
-    // waiting for metadata...
-    m_downloadedMetadata.insert(id, torrentHandle);
-    if (infoHash.isHybrid())
-    {
-        // index hybrid magnet links by both v1 and v2 info hashes
-        const auto altID = TorrentID::fromSHA1Hash(infoHash.v1());
-        m_downloadedMetadata.insert(altID, torrentHandle);
-    }
-    ++m_extraLimit;
-    adjustLimits();
+    m_nativeSession->async_add_torrent(p);
+    m_downloadedMetadata.insert(id, {});
 
     return true;
 }
@@ -5066,18 +5053,36 @@ void SessionImpl::handleAddTorrentAlerts(const std::vector<lt::alert *> &alerts)
 #else
             const InfoHash infoHash {(hasMetadata ? params.ti->info_hash() : params.info_hash)};
 #endif
-            m_loadingTorrents.remove(TorrentID::fromInfoHash(infoHash));
+            if (const auto loadingTorrentsIter = m_loadingTorrents.find(TorrentID::fromInfoHash(infoHash))
+                    ; loadingTorrentsIter != m_loadingTorrents.end())
+            {
+                m_loadingTorrents.erase(loadingTorrentsIter);
+            }
+            else if (const auto downloadedMetadataIter = m_downloadedMetadata.find(TorrentID::fromInfoHash(infoHash))
+                     ; downloadedMetadataIter != m_downloadedMetadata.end())
+            {
+                m_downloadedMetadata.erase(downloadedMetadataIter);
+                if (infoHash.isHybrid())
+                {
+                    // index hybrid magnet links by both v1 and v2 info hashes
+                    const auto altID = TorrentID::fromSHA1Hash(infoHash.v1());
+                    m_downloadedMetadata.remove(altID);
+                }
+            }
 
             return;
         }
 
+
 #ifdef QBT_USES_LIBTORRENT2
-        const auto torrentID = TorrentID::fromInfoHash(alert->handle.info_hashes());
+        const InfoHash infoHash {alert->handle.info_hashes()};
 #else
-        const auto torrentID = TorrentID::fromInfoHash(alert->handle.info_hash());
+        const InfoHash infoHash {alert->handle.info_hash()};
 #endif
-        const auto loadingTorrentsIter = m_loadingTorrents.find(torrentID);
-        if (loadingTorrentsIter != m_loadingTorrents.end())
+        const auto torrentID = TorrentID::fromInfoHash(infoHash);
+
+        if (const auto loadingTorrentsIter = m_loadingTorrents.find(torrentID)
+                ; loadingTorrentsIter != m_loadingTorrents.end())
         {
             LoadTorrentParams params = loadingTorrentsIter.value();
             m_loadingTorrents.erase(loadingTorrentsIter);
@@ -5085,6 +5090,20 @@ void SessionImpl::handleAddTorrentAlerts(const std::vector<lt::alert *> &alerts)
             Torrent *torrent = createTorrent(alert->handle, params);
             loadedTorrents.append(torrent);
         }
+        else if (const auto downloadedMetadataIter = m_downloadedMetadata.find(torrentID)
+                 ; downloadedMetadataIter != m_downloadedMetadata.end())
+        {
+            ++m_extraLimit;
+            adjustLimits();
+
+            downloadedMetadataIter.value() = alert->handle;
+            if (infoHash.isHybrid())
+            {
+                // index hybrid magnet links by both v1 and v2 info hashes
+                const auto altID = TorrentID::fromSHA1Hash(infoHash.v1());
+                m_downloadedMetadata[altID] = alert->handle;
+            }
+        }
     }
 
     if (!loadedTorrents.isEmpty())