Add logging for some alerts

Specifically these alerts:
* i2p_alert
* session_error_alert

PR #19662.

src/base/bittorrent/sessionimpl.cpp

@@ -5371,6 +5371,9 @@ void SessionImpl::handleAlert(const lt::alert *a)
         case lt::state_update_alert::alert_type:
             handleStateUpdateAlert(static_cast<const lt::state_update_alert *>(a));
             break;
+        case lt::session_error_alert::alert_type:
+            handleSessionErrorAlert(static_cast<const lt::session_error_alert *>(a));
+            break;
         case lt::session_stats_alert::alert_type:
             handleSessionStatsAlert(static_cast<const lt::session_stats_alert *>(a));
             break;
@@ -5431,6 +5434,9 @@ void SessionImpl::handleAlert(const lt::alert *a)
         case lt::socks5_alert::alert_type:
             handleSocks5Alert(static_cast<const lt::socks5_alert *>(a));
             break;
+        case lt::i2p_alert::alert_type:
+            handleI2PAlert(static_cast<const lt::i2p_alert *>(a));
+            break;
 #ifdef QBT_USES_LIBTORRENT2
         case lt::torrent_conflict_alert::alert_type:
             handleTorrentConflictAlert(static_cast<const lt::torrent_conflict_alert *>(a));
@@ -5737,6 +5743,12 @@ void SessionImpl::handleExternalIPAlert(const lt::external_ip_alert *p)
     }
 }
 
+void SessionImpl::handleSessionErrorAlert(const lt::session_error_alert *p) const
+{
+    LogMsg(tr("BitTorrent session encountered a serious error. Reason: \"%1\"")
+        .arg(QString::fromStdString(p->message())), Log::CRITICAL);
+}
+
 void SessionImpl::handleSessionStatsAlert(const lt::session_stats_alert *p)
 {
     if (m_refreshEnqueued)
@@ -5931,6 +5943,15 @@ void SessionImpl::handleSocks5Alert(const lt::socks5_alert *p) const
     }
 }
 
+void SessionImpl::handleI2PAlert(const lt::i2p_alert *p) const
+{
+    if (p->error)
+    {
+        LogMsg(tr("I2P error. Message: \"%1\".")
+            .arg(QString::fromStdString(p->message())), Log::WARNING);
+    }
+}
+
 void SessionImpl::handleTrackerAlert(const lt::tracker_alert *a)
 {
     TorrentImpl *torrent = m_torrents.value(a->handle.info_hash());

src/base/bittorrent/sessionimpl.h

@@ -546,11 +546,13 @@ namespace BitTorrent
         void handleListenSucceededAlert(const lt::listen_succeeded_alert *p);
         void handleListenFailedAlert(const lt::listen_failed_alert *p);
         void handleExternalIPAlert(const lt::external_ip_alert *p);
+        void handleSessionErrorAlert(const lt::session_error_alert *p) const;
         void handleSessionStatsAlert(const lt::session_stats_alert *p);
         void handleAlertsDroppedAlert(const lt::alerts_dropped_alert *p) const;
         void handleStorageMovedAlert(const lt::storage_moved_alert *p);
         void handleStorageMovedFailedAlert(const lt::storage_moved_failed_alert *p);
         void handleSocks5Alert(const lt::socks5_alert *p) const;
+        void handleI2PAlert(const lt::i2p_alert *p) const;
         void handleTrackerAlert(const lt::tracker_alert *a);
 #ifdef QBT_USES_LIBTORRENT2
         void handleTorrentConflictAlert(const lt::torrent_conflict_alert *a);