Add final specifier to classes

This allow compilers to generate more efficient code.

src/base/bittorrent/private/filterparserthread.h

@@ -35,7 +35,7 @@
 
 class QDataStream;
 
-class FilterParserThread : public QThread
+class FilterParserThread final : public QThread
 {
     Q_OBJECT
 

src/base/bittorrent/private/nativesessionextension.h

@@ -31,7 +31,7 @@
 #include <libtorrent/extensions.hpp>
 #include <libtorrent/version.hpp>
 
-class NativeSessionExtension : public lt::plugin
+class NativeSessionExtension final : public lt::plugin
 {
 #if (LIBTORRENT_VERSION_NUM >= 10200)
     lt::feature_flags_t implemented_features() override;

src/base/bittorrent/private/nativetorrentextension.h

@@ -32,7 +32,7 @@
 #include <libtorrent/torrent_handle.hpp>
 #include <libtorrent/version.hpp>
 
-class NativeTorrentExtension : public lt::torrent_plugin
+class NativeTorrentExtension final : public lt::torrent_plugin
 {
 public:
     explicit NativeTorrentExtension(const lt::torrent_handle &torrentHandle);

src/base/bittorrent/private/portforwarderimpl.h

@@ -44,7 +44,7 @@ using LTPortMapping = int;
 using LTPortMapping = lt::port_mapping_t;
 #endif
 
-class PortForwarderImpl : public Net::PortForwarder
+class PortForwarderImpl final : public Net::PortForwarder
 {
     Q_OBJECT
     Q_DISABLE_COPY(PortForwarderImpl)

src/base/bittorrent/torrentcreatorthread.h

@@ -48,7 +48,7 @@ namespace BitTorrent
         QStringList urlSeeds;
     };
 
-    class TorrentCreatorThread : public QThread
+    class TorrentCreatorThread final : public QThread
     {
         Q_OBJECT
 

src/base/bittorrent/tracker.h

@@ -70,7 +70,7 @@ namespace BitTorrent
     // *Basic* Bittorrent tracker implementation
     // [BEP-3] The BitTorrent Protocol Specification
     // also see: https://wiki.theory.org/index.php/BitTorrentSpecification#Tracker_HTTP.2FHTTPS_Protocol
-    class Tracker : public QObject, public Http::IRequestHandler, private Http::ResponseBuilder
+    class Tracker final : public QObject, public Http::IRequestHandler, private Http::ResponseBuilder
     {
         Q_OBJECT
         Q_DISABLE_COPY(Tracker)