DolphinQt: Replace QStringLiteral with alternatives where applicable

QStringLiterals generate a buffer so that during runtime there's very
little cost to constructing a QString. However, this also means that
duplicated strings cannot be optimized out into a single entry that gets
referenced everywhere, taking up space in the binary.

Rather than use QStringLiteral(""), we can just use QString{} (the
default constructor) to signify the empty string. This gets rid of an
unnecessary string buffer from being created, saving a tiny bit of
space.

While we're at it, we can just use the character overloads of particular
functions when they're available instead of using a QString overload.
The characters in this case are Latin-1 to begin with, so we can just
specify the characters as QLatin1Char instances to use those overloads.
These will automatically convert to QChar if needed, so this is safe.

Source/Core/DolphinQt/CheatsManager.cpp

@@ -625,8 +625,7 @@ static QString GetResultString(const Result& result)
   case DataType::String:
     return QObject::tr("String Match");
   default:
-    // Make MSVC happy
-    return QStringLiteral("");
+    return {};
   }
 }
 
@@ -722,7 +721,7 @@ void CheatsManager::Reset()
   m_match_table->clear();
   m_watch_table->clear();
   m_match_decimal->setChecked(true);
-  m_result_label->setText(QStringLiteral(""));
+  m_result_label->clear();
 
   Update();
 }

Source/Core/DolphinQt/Config/ARCodeWidget.cpp

@@ -152,8 +152,8 @@ void ARCodeWidget::UpdateList()
   {
     const auto& ar = m_ar_codes[i];
     auto* item = new QListWidgetItem(QString::fromStdString(ar.name)
-                                         .replace(QStringLiteral("&lt;"), QStringLiteral("<"))
-                                         .replace(QStringLiteral("&gt;"), QStringLiteral(">")));
+                                         .replace(QStringLiteral("&lt;"), QChar::fromLatin1('<'))
+                                         .replace(QStringLiteral("&gt;"), QChar::fromLatin1('>')));
 
     item->setFlags(Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsUserCheckable |
                    Qt::ItemIsDragEnabled);

Source/Core/DolphinQt/Config/CheatCodeEditor.cpp

@@ -124,7 +124,7 @@ bool CheatCodeEditor::AcceptAR()
   std::vector<ActionReplay::AREntry> entries;
   std::vector<std::string> encrypted_lines;
 
-  QStringList lines = m_code_edit->toPlainText().split(QStringLiteral("\n"));
+  QStringList lines = m_code_edit->toPlainText().split(QLatin1Char{'\n'});
 
   for (int i = 0; i < lines.size(); i++)
   {
@@ -133,7 +133,7 @@ bool CheatCodeEditor::AcceptAR()
     if (line.isEmpty())
       continue;
 
-    QStringList values = line.split(QStringLiteral(" "));
+    QStringList values = line.split(QLatin1Char{' '});
 
     bool good = true;
 
@@ -152,7 +152,7 @@ bool CheatCodeEditor::AcceptAR()
     }
     else
     {
-      QStringList blocks = line.split(QStringLiteral("-"));
+      QStringList blocks = line.split(QLatin1Char{'-'});
 
       if (blocks.size() == 3 && blocks[0].size() == 4 && blocks[1].size() == 4 &&
           blocks[2].size() == 5)
@@ -230,7 +230,7 @@ bool CheatCodeEditor::AcceptGecko()
 {
   std::vector<Gecko::GeckoCode::Code> entries;
 
-  QStringList lines = m_code_edit->toPlainText().split(QStringLiteral("\n"));
+  QStringList lines = m_code_edit->toPlainText().split(QLatin1Char{'\n'});
 
   for (int i = 0; i < lines.size(); i++)
   {
@@ -239,7 +239,7 @@ bool CheatCodeEditor::AcceptGecko()
     if (line.isEmpty())
       continue;
 
-    QStringList values = line.split(QStringLiteral(" "));
+    QStringList values = line.split(QLatin1Char{' '});
 
     bool good = values.size() == 2;
 
@@ -289,7 +289,7 @@ bool CheatCodeEditor::AcceptGecko()
   m_gecko_code->user_defined = true;
 
   std::vector<std::string> note_lines;
-  for (QString line : m_notes_edit->toPlainText().split(QStringLiteral("\n")))
+  for (const QString& line : m_notes_edit->toPlainText().split(QLatin1Char{'\n'}))
     note_lines.push_back(line.toStdString());
 
   m_gecko_code->notes = std::move(note_lines);

Source/Core/DolphinQt/Config/FilesystemWidget.cpp

@@ -263,7 +263,7 @@ DiscIO::Partition FilesystemWidget::GetPartitionFromID(int id)
 
 void FilesystemWidget::ExtractPartition(const DiscIO::Partition& partition, const QString& out)
 {
-  ExtractDirectory(partition, QStringLiteral(""), out + QStringLiteral("/files"));
+  ExtractDirectory(partition, QString{}, out + QStringLiteral("/files"));
   ExtractSystemData(partition, out);
 }
 

Source/Core/DolphinQt/Config/GameConfigEdit.cpp

@@ -179,7 +179,7 @@ void GameConfigEdit::SetOption(const QString& section, const QString& key, const
     if (value_cursor.isNull())
     {
       section_cursor.clearSelection();
-      section_cursor.insertText(QStringLiteral("\n") + new_line);
+      section_cursor.insertText(QLatin1Char{'\n'} + new_line);
     }
     else
     {

Source/Core/DolphinQt/Config/GeckoCodeWidget.cpp

@@ -280,8 +280,8 @@ void GeckoCodeWidget::UpdateList()
     const auto& code = m_gecko_codes[i];
 
     auto* item = new QListWidgetItem(QString::fromStdString(code.name)
-                                         .replace(QStringLiteral("&lt;"), QStringLiteral("<"))
-                                         .replace(QStringLiteral("&gt;"), QStringLiteral(">")));
+                                         .replace(QStringLiteral("&lt;"), QChar::fromLatin1('<'))
+                                         .replace(QStringLiteral("&gt;"), QChar::fromLatin1('>')));
 
     item->setFlags(Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsUserCheckable |
                    Qt::ItemIsDragEnabled);

Source/Core/DolphinQt/Config/Graphics/EnhancementsWidget.cpp

@@ -189,7 +189,7 @@ void EnhancementsWidget::LoadPPShaders()
   m_pp_effect->setEnabled(supports_postprocessing);
 
   m_pp_effect->setToolTip(supports_postprocessing ?
-                              QStringLiteral("") :
+                              QString{} :
                               tr("%1 doesn't support this feature.")
                                   .arg(tr(g_video_backend->GetDisplayName().c_str())));
 

Source/Core/DolphinQt/Config/Graphics/GeneralWidget.cpp

@@ -299,7 +299,7 @@ void GeneralWidget::OnBackendChanged(const QString& backend_name)
   m_adapter_combo->setEnabled(supports_adapters && !Core::IsRunning());
 
   m_adapter_combo->setToolTip(supports_adapters ?
-                                  QStringLiteral("") :
+                                  QString{} :
                                   tr("%1 doesn't support this feature.")
                                       .arg(tr(g_video_backend->GetDisplayName().c_str())));
 }

Source/Core/DolphinQt/Config/Graphics/HacksWidget.cpp

@@ -129,8 +129,8 @@ void HacksWidget::OnBackendChanged(const QString& backend_name)
 
   const QString tooltip = tr("%1 doesn't support this feature on your system.").arg(backend_name);
 
-  m_gpu_texture_decoding->setToolTip(!gpu_texture_decoding ? tooltip : QStringLiteral(""));
-  m_disable_bounding_box->setToolTip(!bbox ? tooltip : QStringLiteral(""));
+  m_gpu_texture_decoding->setToolTip(!gpu_texture_decoding ? tooltip : QString{});
+  m_disable_bounding_box->setToolTip(!bbox ? tooltip : QString{});
 }
 
 void HacksWidget::ConnectWidgets()

Source/Core/DolphinQt/Config/Mapping/GCKeyboardEmu.cpp

@@ -24,19 +24,19 @@ void GCKeyboardEmu::CreateMainLayout()
   m_main_layout = new QHBoxLayout();
 
   m_main_layout->addWidget(
-      CreateGroupBox(QStringLiteral(""), Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb0x)));
+      CreateGroupBox(QString{}, Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb0x)));
   m_main_layout->addWidget(
-      CreateGroupBox(QStringLiteral(""), Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb1x)));
+      CreateGroupBox(QString{}, Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb1x)));
   m_main_layout->addWidget(
-      CreateGroupBox(QStringLiteral(""), Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb2x)));
+      CreateGroupBox(QString{}, Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb2x)));
   m_main_layout->addWidget(
-      CreateGroupBox(QStringLiteral(""), Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb3x)));
+      CreateGroupBox(QString{}, Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb3x)));
   m_main_layout->addWidget(
-      CreateGroupBox(QStringLiteral(""), Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb4x)));
+      CreateGroupBox(QString{}, Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb4x)));
 
   auto* vbox_layout = new QVBoxLayout();
   vbox_layout->addWidget(
-      CreateGroupBox(QStringLiteral(""), Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb5x)));
+      CreateGroupBox(QString{}, Keyboard::GetGroup(GetPort(), KeyboardGroup::Kb5x)));
 
   m_main_layout->addLayout(vbox_layout);
 

Source/Core/DolphinQt/Config/Mapping/MappingButton.cpp

@@ -32,8 +32,8 @@ constexpr int SLIDER_TICK_COUNT = 100;
 // Escape ampersands and remove ticks
 static QString ToDisplayString(QString&& string)
 {
-  return string.replace(QStringLiteral("&"), QStringLiteral("&&"))
-      .replace(QStringLiteral("`"), QStringLiteral(""));
+  return string.replace(QLatin1Char{'&'}, QStringLiteral("&&"))
+      .replace(QLatin1Char{'`'}, QString{});
 }
 
 bool MappingButton::IsInput() const

Source/Core/DolphinQt/Config/Mapping/MappingCommon.cpp

@@ -33,7 +33,7 @@ QString GetExpressionForControl(const QString& control_name,
   if (control_device != default_device)
   {
     expr += QString::fromStdString(control_device.ToString());
-    expr += QStringLiteral(":");
+    expr += QLatin1Char{':'};
   }
 
   // append the control name

Source/Core/DolphinQt/Config/Mapping/MappingNumeric.cpp

@@ -16,7 +16,7 @@ MappingDouble::MappingDouble(MappingWidget* parent, ControllerEmu::NumericSettin
   setDecimals(2);
 
   if (const auto ui_suffix = m_setting.GetUISuffix())
-    setSuffix(QStringLiteral(" ") + tr(ui_suffix));
+    setSuffix(QLatin1Char{' '} + tr(ui_suffix));
 
   if (const auto ui_description = m_setting.GetUIDescription())
     setToolTip(tr(ui_description));

Source/Core/DolphinQt/Config/Mapping/MappingWindow.cpp

@@ -308,8 +308,8 @@ void MappingWindow::OnGlobalDevicesChanged()
     {
       // Selected device is not currently attached.
       const auto qname = QString::fromStdString(default_device);
-      m_devices_combo->addItem(
-          QStringLiteral("[") + tr("disconnected") + QStringLiteral("] ") + qname, qname);
+      m_devices_combo->addItem(QLatin1Char{'['} + tr("disconnected") + QStringLiteral("] ") + qname,
+                               qname);
       m_devices_combo->setCurrentIndex(m_devices_combo->count() - 1);
     }
   }
@@ -339,7 +339,7 @@ void MappingWindow::SetMappingType(MappingWindow::Type type)
   case Type::MAPPING_GC_MICROPHONE:
     widget = new GCMicrophone(this);
     setWindowTitle(tr("GameCube Microphone Slot %1")
-                       .arg(GetPort() == 0 ? QStringLiteral("A") : QStringLiteral("B")));
+                       .arg(GetPort() == 0 ? QLatin1Char{'A'} : QLatin1Char{'B'}));
     AddWidget(tr("Microphone"), widget);
     break;
   case Type::MAPPING_WIIMOTE_EMU:

Source/Core/DolphinQt/Debugger/BreakpointWidget.cpp

@@ -160,7 +160,7 @@ void BreakpointWidget::Update()
   int i = 0;
   m_table->setRowCount(i);
 
-  auto create_item = [](const QString string = QStringLiteral("")) {
+  const auto create_item = [](const QString string = {}) {
     QTableWidgetItem* item = new QTableWidgetItem(string);
     item->setFlags(Qt::ItemIsEnabled | Qt::ItemIsSelectable);
     return item;
@@ -224,10 +224,10 @@ void BreakpointWidget::Update()
     QString flags;
 
     if (mbp.is_break_on_read)
-      flags.append(QStringLiteral("r"));
+      flags.append(QLatin1Char{'r'});
 
     if (mbp.is_break_on_write)
-      flags.append(QStringLiteral("w"));
+      flags.append(QLatin1Char{'w'});
 
     m_table->setItem(i, 4, create_item(flags));
 

Source/Core/DolphinQt/Debugger/CodeViewWidget.cpp

@@ -422,7 +422,7 @@ void CodeViewWidget::OnSelectionChanged()
   }
   else if (!styleSheet().isEmpty())
   {
-    setStyleSheet(QStringLiteral(""));
+    setStyleSheet(QString{});
   }
 }
 

Source/Core/DolphinQt/Debugger/CodeWidget.cpp

@@ -314,9 +314,9 @@ void CodeWidget::UpdateCallstack()
 
 void CodeWidget::UpdateSymbols()
 {
-  QString selection = m_symbols_list->selectedItems().isEmpty() ?
-                          QStringLiteral("") :
-                          m_symbols_list->selectedItems()[0]->text();
+  const QString selection = m_symbols_list->selectedItems().isEmpty() ?
+                                QString{} :
+                                m_symbols_list->selectedItems()[0]->text();
   m_symbols_list->clear();
 
   for (const auto& symbol : g_symbolDB.Symbols())

Source/Core/DolphinQt/Debugger/MemoryViewWidget.cpp

@@ -169,7 +169,8 @@ void MemoryViewWidget::Update()
     case Type::ASCII:
       update_values([&accessors](u32 address) {
         const char value = accessors->ReadU8(address);
-        return std::isprint(value) ? QString{QChar::fromLatin1(value)} : QStringLiteral(".");
+        return std::isprint(value) ? QString{QChar::fromLatin1(value)} :
+                                     QString{QChar::fromLatin1('.')};
       });
       break;
     case Type::U16:

Source/Core/DolphinQt/Debugger/RegisterWidget.cpp

@@ -81,7 +81,7 @@ void RegisterWidget::CreateWidgets()
   QStringList empty_list;
 
   for (auto i = 0; i < 9; i++)
-    empty_list << QStringLiteral("");
+    empty_list << QString{};
 
   m_table->setHorizontalHeaderLabels(empty_list);
 

Source/Core/DolphinQt/FIFO/FIFOAnalyzer.cpp

@@ -475,7 +475,7 @@ void FIFOAnalyzer::UpdateDescription()
     text += name.empty() ?
                 QStringLiteral("UNKNOWN_%1").arg(*(cmddata + 1), 2, 16, QLatin1Char('0')) :
                 QString::fromStdString(name);
-    text += QStringLiteral("\n");
+    text += QLatin1Char{'\n'};
 
     if (desc.empty())
       text += tr("No description available");