Use `underlying_type` member directly

`LTUnderlyingType` served as a intermediate type for libtorrent 1.1 and
1.2 and is obsoleted now.
Also add helper to convert to underlying type.

src/base/bittorrent/ltunderlyingtype.h

@@ -28,31 +28,8 @@
 
 #pragma once
 
-#include <type_traits>
-
-template <typename T, typename = void>
-struct HasUnderlyingType
-    : std::false_type
-{
-};
-
-template <typename T>
-struct HasUnderlyingType<T, std::void_t<typename T::underlying_type>>
-    : std::true_type
-{
-};
-
-template <typename T, typename = void>
-struct LTUnderlying
-{
-    using type = T;
-};
-
 template <typename T>
-struct LTUnderlying<T, typename std::enable_if_t<HasUnderlyingType<T>::value>>
+typename T::underlying_type toLTUnderlyingType(const T &t)
 {
-    using type = typename T::underlying_type;
-};
-
-template <typename T>
-using LTUnderlyingType = typename LTUnderlying<T>::type;
+    return static_cast<typename T::underlying_type>(t);
+}

src/base/bittorrent/session.cpp

@@ -1489,7 +1489,7 @@ void Session::configurePeerClasses()
     // Proactively do the same for 0.0.0.0 and address_v4::any()
     f.add_rule(lt::address_v4::any()
                , lt::address_v4::broadcast()
-               , 1 << static_cast<LTUnderlyingType<lt::peer_class_t>>(lt::session::global_peer_class_id));
+               , 1 << toLTUnderlyingType(lt::session::global_peer_class_id));
 
     // IPv6 may not be available on OS and the parsing
     // would result in an exception -> abnormal program termination
@@ -1498,7 +1498,7 @@ void Session::configurePeerClasses()
     {
         f.add_rule(lt::address_v6::any()
                    , lt::make_address("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")
-                   , 1 << static_cast<LTUnderlyingType<lt::peer_class_t>>(lt::session::global_peer_class_id));
+                   , 1 << toLTUnderlyingType(lt::session::global_peer_class_id));
     }
     catch (const std::exception &) {}
 
@@ -1507,21 +1507,21 @@ void Session::configurePeerClasses()
         // local networks
         f.add_rule(lt::make_address("10.0.0.0")
                    , lt::make_address("10.255.255.255")
-                   , 1 << static_cast<LTUnderlyingType<lt::peer_class_t>>(lt::session::local_peer_class_id));
+                   , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
         f.add_rule(lt::make_address("172.16.0.0")
                    , lt::make_address("172.31.255.255")
-                   , 1 << static_cast<LTUnderlyingType<lt::peer_class_t>>(lt::session::local_peer_class_id));
+                   , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
         f.add_rule(lt::make_address("192.168.0.0")
                    , lt::make_address("192.168.255.255")
-                   , 1 << static_cast<LTUnderlyingType<lt::peer_class_t>>(lt::session::local_peer_class_id));
+                   , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
         // link local
         f.add_rule(lt::make_address("169.254.0.0")
                    , lt::make_address("169.254.255.255")
-                   , 1 << static_cast<LTUnderlyingType<lt::peer_class_t>>(lt::session::local_peer_class_id));
+                   , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
         // loopback
         f.add_rule(lt::make_address("127.0.0.0")
                    , lt::make_address("127.255.255.255")
-                   , 1 << static_cast<LTUnderlyingType<lt::peer_class_t>>(lt::session::local_peer_class_id));
+                   , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
 
         // IPv6 may not be available on OS and the parsing
         // would result in an exception -> abnormal program termination
@@ -1531,15 +1531,15 @@ void Session::configurePeerClasses()
             // link local
             f.add_rule(lt::make_address("fe80::")
                        , lt::make_address("febf:ffff:ffff:ffff:ffff:ffff:ffff:ffff")
-                       , 1 << static_cast<LTUnderlyingType<lt::peer_class_t>>(lt::session::local_peer_class_id));
+                       , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
             // unique local addresses
             f.add_rule(lt::make_address("fc00::")
                        , lt::make_address("fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")
-                       , 1 << static_cast<LTUnderlyingType<lt::peer_class_t>>(lt::session::local_peer_class_id));
+                       , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
             // loopback
             f.add_rule(lt::address_v6::loopback()
                        , lt::address_v6::loopback()
-                       , 1 << static_cast<LTUnderlyingType<lt::peer_class_t>>(lt::session::local_peer_class_id));
+                       , 1 << toLTUnderlyingType(lt::session::local_peer_class_id));
         }
         catch (const std::exception &) {}
     }
@@ -2377,7 +2377,7 @@ void Session::saveTorrentsQueue() const
     for (const TorrentImpl *torrent : asConst(m_torrents))
     {
         // We require actual (non-cached) queue position here!
-        const int queuePos = static_cast<LTUnderlyingType<lt::queue_position_t>>(torrent->nativeHandle().queue_position());
+        const int queuePos = toLTUnderlyingType(torrent->nativeHandle().queue_position());
         if (queuePos >= 0)
         {
             if (queuePos >= queue.size())

src/base/bittorrent/torrentcreatorthread.cpp

@@ -188,7 +188,7 @@ void TorrentCreatorThread::run()
             , [this, &newTorrent](const lt::piece_index_t n)
         {
             checkInterruptionRequested();
-            sendProgressSignal(static_cast<LTUnderlyingType<lt::piece_index_t>>(n), newTorrent.num_pieces());
+            sendProgressSignal(toLTUnderlyingType(n), newTorrent.num_pieces());
         });
 
         // Set qBittorrent as creator and add user comment to

src/base/bittorrent/torrentimpl.cpp

@@ -84,7 +84,7 @@ namespace
                        , std::back_inserter(out), [](const DownloadPriority priority)
         {
             return static_cast<lt::download_priority_t>(
-                        static_cast<LTUnderlyingType<lt::download_priority_t>>(priority));
+                        static_cast<lt::download_priority_t::underlying_type>(priority));
         });
         return out;
     }
@@ -799,7 +799,7 @@ QVector<DownloadPriority> TorrentImpl::filePriorities() const
     QVector<DownloadPriority> ret;
     std::transform(fp.cbegin(), fp.cend(), std::back_inserter(ret), [](lt::download_priority_t priority)
     {
-        return static_cast<DownloadPriority>(static_cast<LTUnderlyingType<lt::download_priority_t>>(priority));
+        return static_cast<DownloadPriority>(toLTUnderlyingType(priority));
     });
     return ret;
 }
@@ -1250,7 +1250,7 @@ QBitArray TorrentImpl::downloadingPieces() const
     m_nativeHandle.get_download_queue(queue);
 
     for (const lt::partial_piece_info &info : queue)
-        result.setBit(static_cast<LTUnderlyingType<lt::piece_index_t>>(info.piece_index));
+        result.setBit(toLTUnderlyingType(info.piece_index));
 
     return result;
 }
@@ -1900,7 +1900,7 @@ void TorrentImpl::handleFileRenamedAlert(const lt::file_renamed_alert *p)
 void TorrentImpl::handleFileRenameFailedAlert(const lt::file_rename_failed_alert *p)
 {
     LogMsg(tr("File rename failed. Torrent: \"%1\", file: \"%2\", reason: \"%3\"")
-        .arg(name(), filePath(static_cast<LTUnderlyingType<lt::file_index_t>>(p->index))
+        .arg(name(), filePath(toLTUnderlyingType(p->index))
              , QString::fromLocal8Bit(p->error.message().c_str())), Log::WARNING);
 
     m_oldPath[p->index].removeFirst();
@@ -1919,13 +1919,13 @@ void TorrentImpl::handleFileCompletedAlert(const lt::file_completed_alert *p)
     qDebug("A file completed download in torrent \"%s\"", qUtf8Printable(name()));
     if (m_session->isAppendExtensionEnabled())
     {
-        QString name = filePath(static_cast<LTUnderlyingType<lt::file_index_t>>(p->index));
+        QString name = filePath(toLTUnderlyingType(p->index));
         if (name.endsWith(QB_EXT))
         {
             const QString oldName = name;
             name.chop(QB_EXT.size());
             qDebug("Renaming %s to %s", qUtf8Printable(oldName), qUtf8Printable(name));
-            renameFile(static_cast<LTUnderlyingType<lt::file_index_t>>(p->index), name);
+            renameFile(toLTUnderlyingType(p->index), name);
         }
     }
 }