Make working set limit available only on libtorrent 2.0.x builds

You can already control the cache size in libtorrent 1.2.x so it doesn't make sense to implement this limit for all use cases. Also there are some downsides to using working set size to limit memory usage such as unresponsive GUI when limit gets hit.

src/app/application.cpp

@@ -220,7 +220,9 @@ void Application::setMemoryWorkingSetLimit(const int size)
         return;
 
     m_storeMemoryWorkingSetLimit = size;
+#ifdef QBT_USES_LIBTORRENT2
     applyMemoryWorkingSetLimit();
+#endif
 }
 #endif
 
@@ -621,7 +623,7 @@ void Application::processParams(const QStringList &params)
 
 int Application::exec(const QStringList &params)
 {
-#ifdef Q_OS_WIN
+#if (defined(Q_OS_WIN) && defined(QBT_USES_LIBTORRENT2))
     applyMemoryWorkingSetLimit();
 #endif
 
@@ -794,7 +796,7 @@ void Application::shutdownCleanup(QSessionManager &manager)
 }
 #endif
 
-#ifdef Q_OS_WIN
+#if (defined(Q_OS_WIN) && defined(QBT_USES_LIBTORRENT2))
 void Application::applyMemoryWorkingSetLimit()
 {
     const SIZE_T UNIT_SIZE = 1024 * 1024; // MiB

src/app/application.h

@@ -126,7 +126,7 @@ private slots:
 #endif
 
 private:
-#ifdef Q_OS_WIN
+#if (defined(Q_OS_WIN) && defined(QBT_USES_LIBTORRENT2))
     void applyMemoryWorkingSetLimit();
 #endif
     void initializeTranslation();

src/gui/advancedsettings.cpp

@@ -62,9 +62,11 @@ namespace
         // qBittorrent section
         QBITTORRENT_HEADER,
         RESUME_DATA_STORAGE,
+#if (defined(Q_OS_WIN) && defined(QBT_USES_LIBTORRENT2))
+        MEMORY_WORKING_SET_LIMIT,
+#endif
 #if defined(Q_OS_WIN)
         OS_MEMORY_PRIORITY,
-        MEMORY_WORKING_SET_LIMIT,
 #endif
         // network interface
         NETWORK_IFACE,
@@ -198,7 +200,9 @@ void AdvancedSettings::saveAdvancedSettings()
     }
     session->setOSMemoryPriority(prio);
 
+#ifdef QBT_USES_LIBTORRENT2
     static_cast<Application *>(QCoreApplication::instance())->setMemoryWorkingSetLimit(m_spinBoxMemoryWorkingSetLimit.value());
+#endif
 #endif
     // Async IO threads
     session->setAsyncIOThreads(m_spinBoxAsyncIOThreads.value());
@@ -443,6 +447,7 @@ void AdvancedSettings::loadAdvancedSettings()
         + ' ' + makeLink("https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/ns-processthreadsapi-memory_priority_information", "(?)"))
         , &m_comboBoxOSMemoryPriority);
 
+#ifdef QBT_USES_LIBTORRENT2
     m_spinBoxMemoryWorkingSetLimit.setMinimum(1);
     m_spinBoxMemoryWorkingSetLimit.setMaximum(std::numeric_limits<int>::max());
     m_spinBoxMemoryWorkingSetLimit.setSuffix(tr(" MiB"));
@@ -451,6 +456,7 @@ void AdvancedSettings::loadAdvancedSettings()
     addRow(MEMORY_WORKING_SET_LIMIT, (tr("Physical memory (RAM) usage limit")
         + ' ' + makeLink("https://wikipedia.org/wiki/Working_set", "(?)"))
         , &m_spinBoxMemoryWorkingSetLimit);
+#endif
 #endif
 
     // Async IO threads

src/gui/advancedsettings.h

@@ -82,8 +82,10 @@ private:
     // OS dependent settings
 #if defined(Q_OS_WIN)
     QComboBox m_comboBoxOSMemoryPriority;
+#ifdef QBT_USES_LIBTORRENT2
     QSpinBox m_spinBoxMemoryWorkingSetLimit;
 #endif
+#endif
 
 #ifndef Q_OS_MACOS
     QCheckBox m_checkBoxIconsInMenusEnabled;