diff --git a/heaptrack.waybar.2711357.zst b/heaptrack.waybar.2711357.zst
new file mode 100644
index 00000000..88921cba
Binary files /dev/null and b/heaptrack.waybar.2711357.zst differ
diff --git a/include/modules/disk.hpp b/include/modules/disk.hpp
index 1b4f3176..b576e19f 100644
--- a/include/modules/disk.hpp
+++ b/include/modules/disk.hpp
@@ -22,7 +22,7 @@ class Disk : public ALabel {
   std::string path_;
   std::string unit_;
 
-  float calc_specific_divisor(const std::string divisor);
+  float calc_specific_divisor(const std::string& divisor);
 };
 
 }  // namespace waybar::modules
diff --git a/include/modules/hyprland/windowcreationpayload.hpp b/include/modules/hyprland/windowcreationpayload.hpp
index 226a7c41..906be805 100644
--- a/include/modules/hyprland/windowcreationpayload.hpp
+++ b/include/modules/hyprland/windowcreationpayload.hpp
@@ -40,10 +40,11 @@ struct WindowRepr {
 
 class WindowCreationPayload {
  public:
-  WindowCreationPayload(std::string workspace_name, WindowAddress window_address,
+  WindowCreationPayload(const std::string& workspace_name, WindowAddress window_address,
                         WindowRepr window_repr);
-  WindowCreationPayload(std::string workspace_name, WindowAddress window_address,
-                        std::string window_class, std::string window_title, bool is_active);
+  WindowCreationPayload(const std::string& workspace_name, WindowAddress window_address,
+                        const std::string& window_class, const std::string& window_title,
+                        bool is_active);
   WindowCreationPayload(Json::Value const& client_data);
 
   int incrementTimeSpentUncreated();
diff --git a/include/modules/hyprland/workspaces.hpp b/include/modules/hyprland/workspaces.hpp
index 8bf88888..0cec3c1d 100644
--- a/include/modules/hyprland/workspaces.hpp
+++ b/include/modules/hyprland/workspaces.hpp
@@ -59,7 +59,7 @@ class Workspaces : public AModule, public EventHandler {
   enum class ActiveWindowPosition { NONE, FIRST, LAST };
   auto activeWindowPosition() const -> ActiveWindowPosition { return m_activeWindowPosition; }
 
-  std::string getRewrite(std::string window_class, std::string window_title);
+  std::string getRewrite(const std::string& window_class, const std::string& window_title);
   std::string& getWindowSeparator() { return m_formatWindowSeparator; }
   bool isWorkspaceIgnored(std::string const& workspace_name);
 
diff --git a/include/modules/mpd/mpd.hpp b/include/modules/mpd/mpd.hpp
index 32d526e9..9d81638e 100644
--- a/include/modules/mpd/mpd.hpp
+++ b/include/modules/mpd/mpd.hpp
@@ -44,7 +44,7 @@ class MPD : public ALabel {
   std::string getFilename() const;
   void setLabel();
   std::string getStateIcon() const;
-  std::string getOptionIcon(std::string optionName, bool activated) const;
+  std::string getOptionIcon(const std::string& optionName, bool activated) const;
 
   // GUI-side methods
   bool handlePlayPause(GdkEventButton* const&);
diff --git a/include/modules/sni/host.hpp b/include/modules/sni/host.hpp
index 6c62ac31..7248ad2f 100644
--- a/include/modules/sni/host.hpp
+++ b/include/modules/sni/host.hpp
@@ -30,7 +30,7 @@ class Host {
   static void itemUnregistered(SnWatcher*, const gchar*, gpointer);
 
   std::tuple<std::string, std::string> getBusNameAndObjectPath(const std::string);
-  void addRegisteredItem(std::string service);
+  void addRegisteredItem(const std::string& service);
 
   std::vector<std::unique_ptr<Item>> items_;
   const std::string bus_name_;
diff --git a/include/modules/sway/bar.hpp b/include/modules/sway/bar.hpp
index fd48e5a3..381c6c37 100644
--- a/include/modules/sway/bar.hpp
+++ b/include/modules/sway/bar.hpp
@@ -37,7 +37,7 @@ class BarIpcClient {
   void onModeUpdate(bool visible_by_modifier);
   void onUrgencyUpdate(bool visible_by_urgency);
   void update();
-  bool isModuleEnabled(std::string name);
+  bool isModuleEnabled(const std::string& name);
 
   Bar& bar_;
   util::JsonParser parser_;
diff --git a/include/modules/sway/language.hpp b/include/modules/sway/language.hpp
index 91aa181d..470b9879 100644
--- a/include/modules/sway/language.hpp
+++ b/include/modules/sway/language.hpp
@@ -47,7 +47,7 @@ class Language : public ALabel, public sigc::trackable {
   void onEvent(const struct Ipc::ipc_response&);
   void onCmd(const struct Ipc::ipc_response&);
 
-  auto set_current_layout(std::string current_layout) -> void;
+  auto set_current_layout(const std::string& current_layout) -> void;
   auto init_layouts_map(const std::vector<std::string>& used_layouts) -> void;
 
   const static std::string XKB_LAYOUT_NAMES_KEY;
diff --git a/include/modules/sway/workspaces.hpp b/include/modules/sway/workspaces.hpp
index d8a9e18a..14528841 100644
--- a/include/modules/sway/workspaces.hpp
+++ b/include/modules/sway/workspaces.hpp
@@ -27,7 +27,7 @@ class Workspaces : public AModule, public sigc::trackable {
   static constexpr std::string_view persistent_workspace_switch_cmd_ =
       R"(workspace {} "{}"; move workspace to output "{}"; workspace {} "{}")";
 
-  static int convertWorkspaceNameToNum(std::string name);
+  static int convertWorkspaceNameToNum(const std::string& name);
   static int windowRewritePriorityFunction(std::string const& window_rule);
 
   void onCmd(const struct Ipc::ipc_response&);
@@ -40,7 +40,7 @@ class Workspaces : public AModule, public sigc::trackable {
   std::string getIcon(const std::string&, const Json::Value&);
   std::string getCycleWorkspace(std::vector<Json::Value>::iterator, bool prev) const;
   uint16_t getWorkspaceIndex(const std::string& name) const;
-  static std::string trimWorkspaceName(std::string);
+  static std::string trimWorkspaceName(const std::string&);
   bool handleScroll(GdkEventScroll* /*unused*/) override;
 
   const Bar& bar_;
diff --git a/include/util/SafeSignal.hpp b/include/util/SafeSignal.hpp
index 1e901792..afb0893e 100644
--- a/include/util/SafeSignal.hpp
+++ b/include/util/SafeSignal.hpp
@@ -3,10 +3,10 @@
 #include <glibmm/dispatcher.h>
 #include <sigc++/signal.h>
 
+#include <cstddef>
 #include <functional>
 #include <mutex>
 #include <queue>
-#include <cstddef>
 #include <thread>
 #include <tuple>
 #include <type_traits>
diff --git a/include/util/sleeper_thread.hpp b/include/util/sleeper_thread.hpp
index 966772a2..1f3a372d 100644
--- a/include/util/sleeper_thread.hpp
+++ b/include/util/sleeper_thread.hpp
@@ -72,8 +72,7 @@ class SleeperThread {
     std::unique_lock lk(mutex_);
     CancellationGuard cancel_lock;
     return condvar_.wait(lk, [this] {
-      return signal_.load(std::memory_order_relaxed) ||
-             !do_run_.load(std::memory_order_relaxed);
+      return signal_.load(std::memory_order_relaxed) || !do_run_.load(std::memory_order_relaxed);
     });
   }
 
@@ -87,8 +86,7 @@ class SleeperThread {
       wait_end = now + dur;
     }
     return condvar_.wait_until(lk, wait_end, [this] {
-      return signal_.load(std::memory_order_relaxed) ||
-             !do_run_.load(std::memory_order_relaxed);
+      return signal_.load(std::memory_order_relaxed) || !do_run_.load(std::memory_order_relaxed);
     });
   }
 
@@ -98,8 +96,7 @@ class SleeperThread {
     std::unique_lock lk(mutex_);
     CancellationGuard cancel_lock;
     return condvar_.wait_until(lk, time_point, [this] {
-      return signal_.load(std::memory_order_relaxed) ||
-             !do_run_.load(std::memory_order_relaxed);
+      return signal_.load(std::memory_order_relaxed) || !do_run_.load(std::memory_order_relaxed);
     });
   }
 
diff --git a/src/modules/cffi.cpp b/src/modules/cffi.cpp
index 930c4d47..c3f1398f 100644
--- a/src/modules/cffi.cpp
+++ b/src/modules/cffi.cpp
@@ -71,6 +71,7 @@ CFFI::CFFI(const std::string& name, const std::string& id, const Json::Value& co
 
   // Prepare config_entries array
   std::vector<ffi::wbcffi_config_entry> config_entries;
+  config_entries.reserve(keys.size());
   for (size_t i = 0; i < keys.size(); i++) {
     config_entries.push_back({keys[i].c_str(), config_entries_stringstor[i].c_str()});
   }
diff --git a/src/modules/cpu_frequency/linux.cpp b/src/modules/cpu_frequency/linux.cpp
index 1f368789..83f06aa5 100644
--- a/src/modules/cpu_frequency/linux.cpp
+++ b/src/modules/cpu_frequency/linux.cpp
@@ -26,7 +26,7 @@ std::vector<float> waybar::modules::CpuFrequency::parseCpuFrequencies() {
     if (std::filesystem::exists(cpufreq_dir)) {
       std::vector<std::string> frequency_files = {"/cpuinfo_min_freq", "/cpuinfo_max_freq"};
       for (auto& p : std::filesystem::directory_iterator(cpufreq_dir)) {
-        for (auto freq_file : frequency_files) {
+        for (const auto& freq_file : frequency_files) {
           std::string freq_file_path = p.path().string() + freq_file;
           if (std::filesystem::exists(freq_file_path)) {
             std::string freq_value;
diff --git a/src/modules/disk.cpp b/src/modules/disk.cpp
index fd7ef817..462940b2 100644
--- a/src/modules/disk.cpp
+++ b/src/modules/disk.cpp
@@ -92,7 +92,7 @@ auto waybar::modules::Disk::update() -> void {
   ALabel::update();
 }
 
-float waybar::modules::Disk::calc_specific_divisor(std::string divisor) {
+float waybar::modules::Disk::calc_specific_divisor(const std::string& divisor) {
   if (divisor == "kB") {
     return 1000.0;
   } else if (divisor == "kiB") {
diff --git a/src/modules/hyprland/window.cpp b/src/modules/hyprland/window.cpp
index 1fddb45b..97d49eaf 100644
--- a/src/modules/hyprland/window.cpp
+++ b/src/modules/hyprland/window.cpp
@@ -124,7 +124,7 @@ auto Window::getActiveWorkspace(const std::string& monitorName) -> Workspace {
   const auto monitors = IPC::inst().getSocket1JsonReply("monitors");
   if (monitors.isArray()) {
     auto monitor = std::ranges::find_if(
-        monitors, [&](Json::Value monitor) { return monitor["name"] == monitorName; });
+        monitors, [&](const Json::Value& monitor) { return monitor["name"] == monitorName; });
     if (monitor == std::end(monitors)) {
       spdlog::warn("Monitor not found: {}", monitorName);
       return Workspace{
@@ -139,7 +139,7 @@ auto Window::getActiveWorkspace(const std::string& monitorName) -> Workspace {
     const auto workspaces = IPC::inst().getSocket1JsonReply("workspaces");
     if (workspaces.isArray()) {
       auto workspace = std::ranges::find_if(
-          workspaces, [&](Json::Value workspace) { return workspace["id"] == id; });
+          workspaces, [&](const Json::Value& workspace) { return workspace["id"] == id; });
       if (workspace == std::end(workspaces)) {
         spdlog::warn("No workspace with id {}", id);
         return Workspace{
@@ -190,7 +190,7 @@ void Window::queryActiveWorkspace() {
     const auto clients = m_ipc.getSocket1JsonReply("clients");
     if (clients.isArray()) {
       auto activeWindow = std::ranges::find_if(
-          clients, [&](Json::Value window) { return window["address"] == workspace_.last_window; });
+          clients, [&](const Json::Value& window) { return window["address"] == workspace_.last_window; });
 
       if (activeWindow == std::end(clients)) {
         focused_ = false;
@@ -200,19 +200,19 @@ void Window::queryActiveWorkspace() {
       windowData_ = WindowData::parse(*activeWindow);
       updateAppIconName(windowData_.class_name, windowData_.initial_class_name);
       std::vector<Json::Value> workspaceWindows;
-      std::ranges::copy_if(clients, std::back_inserter(workspaceWindows), [&](Json::Value window) {
+      std::ranges::copy_if(clients, std::back_inserter(workspaceWindows), [&](const Json::Value& window) {
         return window["workspace"]["id"] == workspace_.id && window["mapped"].asBool();
       });
-      swallowing_ = std::ranges::any_of(workspaceWindows, [&](Json::Value window) {
+      swallowing_ = std::ranges::any_of(workspaceWindows, [&](const Json::Value& window) {
         return !window["swallowing"].isNull() && window["swallowing"].asString() != "0x0";
       });
       std::vector<Json::Value> visibleWindows;
       std::ranges::copy_if(workspaceWindows, std::back_inserter(visibleWindows),
-                           [&](Json::Value window) { return !window["hidden"].asBool(); });
+                           [&](const Json::Value& window) { return !window["hidden"].asBool(); });
       solo_ = 1 == std::count_if(visibleWindows.begin(), visibleWindows.end(),
-                                 [&](Json::Value window) { return !window["floating"].asBool(); });
+                                 [&](const Json::Value& window) { return !window["floating"].asBool(); });
       allFloating_ = std::ranges::all_of(
-          visibleWindows, [&](Json::Value window) { return window["floating"].asBool(); });
+          visibleWindows, [&](const Json::Value& window) { return window["floating"].asBool(); });
       fullscreen_ = windowData_.fullscreen;
 
       // Fullscreen windows look like they are solo
diff --git a/src/modules/hyprland/windowcount.cpp b/src/modules/hyprland/windowcount.cpp
index ab573cca..5f5db80c 100644
--- a/src/modules/hyprland/windowcount.cpp
+++ b/src/modules/hyprland/windowcount.cpp
@@ -79,7 +79,7 @@ auto WindowCount::getActiveWorkspace(const std::string& monitorName) -> Workspac
   const auto monitors = m_ipc.getSocket1JsonReply("monitors");
   if (monitors.isArray()) {
     auto monitor = std::ranges::find_if(
-        monitors, [&](Json::Value monitor) { return monitor["name"] == monitorName; });
+        monitors, [&](const Json::Value& monitor) { return monitor["name"] == monitorName; });
     if (monitor == std::end(monitors)) {
       spdlog::warn("Monitor not found: {}", monitorName);
       return Workspace{
@@ -93,7 +93,7 @@ auto WindowCount::getActiveWorkspace(const std::string& monitorName) -> Workspac
     const auto workspaces = m_ipc.getSocket1JsonReply("workspaces");
     if (workspaces.isArray()) {
       auto workspace = std::ranges::find_if(
-          workspaces, [&](Json::Value workspace) { return workspace["id"] == id; });
+          workspaces, [&](const Json::Value& workspace) { return workspace["id"] == id; });
       if (workspace == std::end(workspaces)) {
         spdlog::warn("No workspace with id {}", id);
         return Workspace{
diff --git a/src/modules/hyprland/windowcreationpayload.cpp b/src/modules/hyprland/windowcreationpayload.cpp
index 61ea606f..5ace5b32 100644
--- a/src/modules/hyprland/windowcreationpayload.cpp
+++ b/src/modules/hyprland/windowcreationpayload.cpp
@@ -19,7 +19,7 @@ WindowCreationPayload::WindowCreationPayload(Json::Value const& client_data)
   clearWorkspaceName();
 }
 
-WindowCreationPayload::WindowCreationPayload(std::string workspace_name,
+WindowCreationPayload::WindowCreationPayload(const std::string& workspace_name,
                                              WindowAddress window_address, WindowRepr window_repr)
     : m_window(std::move(window_repr)),
       m_windowAddress(std::move(window_address)),
@@ -28,9 +28,10 @@ WindowCreationPayload::WindowCreationPayload(std::string workspace_name,
   clearWorkspaceName();
 }
 
-WindowCreationPayload::WindowCreationPayload(std::string workspace_name,
-                                             WindowAddress window_address, std::string window_class,
-                                             std::string window_title, bool is_active)
+WindowCreationPayload::WindowCreationPayload(const std::string& workspace_name,
+                                             WindowAddress window_address,
+                                             const std::string& window_class,
+                                             const std::string& window_title, bool is_active)
     : m_window(std::make_pair(std::move(window_class), std::move(window_title))),
       m_windowAddress(std::move(window_address)),
       m_workspaceName(std::move(workspace_name)),
diff --git a/src/modules/hyprland/workspace.cpp b/src/modules/hyprland/workspace.cpp
index 87933ac0..21e7ef9b 100644
--- a/src/modules/hyprland/workspace.cpp
+++ b/src/modules/hyprland/workspace.cpp
@@ -96,7 +96,7 @@ bool Workspace::handleClicked(GdkEventButton* bt) const {
 
 void Workspace::initializeWindowMap(const Json::Value& clients_data) {
   m_windowMap.clear();
-  for (auto client : clients_data) {
+  for (const auto& client : clients_data) {
     if (client["workspace"]["id"].asInt() == id()) {
       insertWindow({client});
     }
diff --git a/src/modules/hyprland/workspaces.cpp b/src/modules/hyprland/workspaces.cpp
index 88b01223..cbd14f90 100644
--- a/src/modules/hyprland/workspaces.cpp
+++ b/src/modules/hyprland/workspaces.cpp
@@ -155,7 +155,8 @@ void Workspaces::extendOrphans(int workspaceId, Json::Value const& clientsJson)
   }
 }
 
-std::string Workspaces::getRewrite(std::string window_class, std::string window_title) {
+std::string Workspaces::getRewrite(const std::string& window_class,
+                                   const std::string& window_title) {
   std::string windowReprKey;
   if (windowRewriteConfigUsesTitle()) {
     windowReprKey = fmt::format("class<{}> title<{}>", window_class, window_title);
@@ -196,7 +197,7 @@ void Workspaces::initializeWorkspaces() {
   auto const workspacesJson = m_ipc.getSocket1JsonReply("workspaces");
   auto const clientsJson = m_ipc.getSocket1JsonReply("clients");
 
-  for (Json::Value workspaceJson : workspacesJson) {
+  for (const auto& workspaceJson : workspacesJson) {
     std::string workspaceName = workspaceJson["name"].asString();
     if ((allOutputs() || m_bar.output->name == workspaceJson["monitor"].asString()) &&
         (!workspaceName.starts_with("special") || showSpecial()) &&
@@ -400,7 +401,7 @@ void Workspaces::onWorkspaceCreated(std::string const& payload, Json::Value cons
   auto const workspaceRules = m_ipc.getSocket1JsonReply("workspacerules");
   auto const workspacesJson = m_ipc.getSocket1JsonReply("workspaces");
 
-  for (Json::Value workspaceJson : workspacesJson) {
+  for (auto workspaceJson : workspacesJson) {
     const auto currentId = workspaceJson["id"].asInt();
     if (currentId == *workspaceId) {
       std::string workspaceName = workspaceJson["name"].asString();
@@ -1003,7 +1004,7 @@ void Workspaces::setUrgentWorkspace(std::string const& windowaddress) {
   const Json::Value clientsJson = m_ipc.getSocket1JsonReply("clients");
   int workspaceId = -1;
 
-  for (Json::Value clientJson : clientsJson) {
+  for (const auto& clientJson : clientsJson) {
     if (clientJson["address"].asString().ends_with(windowaddress)) {
       workspaceId = clientJson["workspace"]["id"].asInt();
       break;
diff --git a/src/modules/inhibitor.cpp b/src/modules/inhibitor.cpp
index 170d0508..43c1f83e 100644
--- a/src/modules/inhibitor.cpp
+++ b/src/modules/inhibitor.cpp
@@ -85,7 +85,8 @@ auto getInhibitors(const Json::Value& config) -> std::string {
   if (config["what"].isArray()) {
     inhibitors = checkInhibitor(config["what"][0].asString());
     for (decltype(config["what"].size()) i = 1; i < config["what"].size(); ++i) {
-      inhibitors += ":" + checkInhibitor(config["what"][i].asString());
+      inhibitors.append(":");
+      inhibitors.append(checkInhibitor(config["what"][i].asString()));
     }
     return inhibitors;
   }
diff --git a/src/modules/mpd/mpd.cpp b/src/modules/mpd/mpd.cpp
index 1e28a58a..9874f458 100644
--- a/src/modules/mpd/mpd.cpp
+++ b/src/modules/mpd/mpd.cpp
@@ -239,7 +239,8 @@ std::string waybar::modules::MPD::getStateIcon() const {
   }
 }
 
-std::string waybar::modules::MPD::getOptionIcon(std::string optionName, bool activated) const {
+std::string waybar::modules::MPD::getOptionIcon(const std::string& optionName,
+                                                bool activated) const {
   if (!config_[optionName + "-icons"].isObject()) {
     return "";
   }
diff --git a/src/modules/mpris/mpris.cpp b/src/modules/mpris/mpris.cpp
index 1bdd7df6..93f73690 100644
--- a/src/modules/mpris/mpris.cpp
+++ b/src/modules/mpris/mpris.cpp
@@ -109,6 +109,7 @@ Mpris::Mpris(const std::string& id, const Json::Value& config)
     player_ = config_["player"].asString();
   }
   if (config_["ignored-players"].isArray()) {
+    ignored_players_.reserve(config_["ignored-players"].size());
     for (const auto& item : config_["ignored-players"]) {
       if (item.isString()) {
         ignored_players_.push_back(item.asString());
diff --git a/src/modules/network.cpp b/src/modules/network.cpp
index a25024e8..a4f2bcc2 100644
--- a/src/modules/network.cpp
+++ b/src/modules/network.cpp
@@ -321,6 +321,7 @@ auto waybar::modules::Network::update() -> void {
   } else if (addr_pref_ == ip_addr_pref::IPV6) {
     final_ipaddr_ = ipaddr6_;
   } else if (addr_pref_ == ip_addr_pref::IPV4_6) {
+    final_ipaddr_.reserve(ipaddr_.length() + ipaddr6_.length() + 1);
     final_ipaddr_ = ipaddr_;
     final_ipaddr_ += '\n';
     final_ipaddr_ += ipaddr6_;
diff --git a/src/modules/niri/language.cpp b/src/modules/niri/language.cpp
index 3359ef4c..14ca555f 100644
--- a/src/modules/niri/language.cpp
+++ b/src/modules/niri/language.cpp
@@ -32,6 +32,7 @@ void Language::updateFromIPC() {
   auto ipcLock = gIPC->lockData();
 
   layouts_.clear();
+  layouts_.reserve(gIPC->keyboardLayoutNames().size());
   for (const auto& fullName : gIPC->keyboardLayoutNames()) layouts_.push_back(getLayout(fullName));
 
   current_idx_ = gIPC->keyboardLayoutCurrent();
diff --git a/src/modules/sni/host.cpp b/src/modules/sni/host.cpp
index 75501207..6bd1154a 100644
--- a/src/modules/sni/host.cpp
+++ b/src/modules/sni/host.cpp
@@ -132,7 +132,7 @@ std::tuple<std::string, std::string> Host::getBusNameAndObjectPath(const std::st
   return {service, "/StatusNotifierItem"};
 }
 
-void Host::addRegisteredItem(std::string service) {
+void Host::addRegisteredItem(const std::string& service) {
   std::string bus_name, object_path;
   std::tie(bus_name, object_path) = getBusNameAndObjectPath(service);
   auto it = std::find_if(items_.begin(), items_.end(), [&bus_name, &object_path](const auto& item) {
diff --git a/src/modules/sni/item.cpp b/src/modules/sni/item.cpp
index d33765d2..1428bd8e 100644
--- a/src/modules/sni/item.cpp
+++ b/src/modules/sni/item.cpp
@@ -336,11 +336,20 @@ Glib::RefPtr<Gdk::Pixbuf> Item::extractPixBuf(GVariant* variant) {
           if (array != nullptr) {
             g_free(array);
           }
-#if GLIB_MAJOR_VERSION >= 2 && GLIB_MINOR_VERSION >= 68
-          array = static_cast<guchar*>(g_memdup2(data, size));
-#else
-          array = static_cast<guchar*>(g_memdup(data, size));
-#endif
+          // We must allocate our own array because the data from GVariant is read-only
+          // and we need to modify it to convert ARGB to RGBA.
+          array = static_cast<guchar*>(g_malloc(size));
+
+          // Copy and convert ARGB to RGBA in one pass to avoid g_memdup2 overhead
+          const guchar* src = static_cast<const guchar*>(data);
+          for (gsize i = 0; i < size; i += 4) {
+            guchar alpha = src[i];
+            array[i] = src[i + 1];
+            array[i + 1] = src[i + 2];
+            array[i + 2] = src[i + 3];
+            array[i + 3] = alpha;
+          }
+
           lwidth = width;
           lheight = height;
         }
@@ -349,14 +358,6 @@ Glib::RefPtr<Gdk::Pixbuf> Item::extractPixBuf(GVariant* variant) {
   }
   g_variant_iter_free(it);
   if (array != nullptr) {
-    /* argb to rgba */
-    for (uint32_t i = 0; i < 4U * lwidth * lheight; i += 4) {
-      guchar alpha = array[i];
-      array[i] = array[i + 1];
-      array[i + 1] = array[i + 2];
-      array[i + 2] = array[i + 3];
-      array[i + 3] = alpha;
-    }
     return Gdk::Pixbuf::create_from_data(array, Gdk::Colorspace::COLORSPACE_RGB, true, 8, lwidth,
                                          lheight, 4 * lwidth, &pixbuf_data_deleter);
   }
@@ -422,8 +423,6 @@ Glib::RefPtr<Gdk::Pixbuf> Item::getIconPixbuf() {
 }
 
 Glib::RefPtr<Gdk::Pixbuf> Item::getIconByName(const std::string& name, int request_size) {
-  icon_theme->rescan_if_needed();
-
   if (!icon_theme_path.empty()) {
     auto icon_info = icon_theme->lookup_icon(name.c_str(), request_size,
                                              Gtk::IconLookupFlags::ICON_LOOKUP_FORCE_SIZE);
diff --git a/src/modules/sway/bar.cpp b/src/modules/sway/bar.cpp
index f28b0502..f374f1c1 100644
--- a/src/modules/sway/bar.cpp
+++ b/src/modules/sway/bar.cpp
@@ -60,7 +60,7 @@ BarIpcClient::BarIpcClient(waybar::Bar& bar) : bar_{bar} {
   });
 }
 
-bool BarIpcClient::isModuleEnabled(std::string name) {
+bool BarIpcClient::isModuleEnabled(const std::string& name) {
   for (const auto& section : {"modules-left", "modules-center", "modules-right"}) {
     if (const auto& modules = bar_.config.get(section, {}); modules.isArray()) {
       for (const auto& module : modules) {
diff --git a/src/modules/sway/language.cpp b/src/modules/sway/language.cpp
index f4cfa6c3..2e1103d3 100644
--- a/src/modules/sway/language.cpp
+++ b/src/modules/sway/language.cpp
@@ -124,7 +124,7 @@ auto Language::update() -> void {
   ALabel::update();
 }
 
-auto Language::set_current_layout(std::string current_layout) -> void {
+auto Language::set_current_layout(const std::string& current_layout) -> void {
   label_.get_style_context()->remove_class(layout_.short_name);
   layout_ = layouts_map_[current_layout];
   label_.get_style_context()->add_class(layout_.short_name);
diff --git a/src/modules/sway/window.cpp b/src/modules/sway/window.cpp
index 830a4120..2908b85c 100644
--- a/src/modules/sway/window.cpp
+++ b/src/modules/sway/window.cpp
@@ -184,9 +184,9 @@ std::tuple<std::string, std::string, std::string, std::string> getWindowInfo(
         continue;
       }
       if (!marks.empty()) {
-        marks += ',';
+        marks.append(",");
       }
-      marks += m.asString();
+      marks.append(m.asString());
     }
   }
   return {app_id, app_class, shell, marks};
diff --git a/src/modules/sway/workspaces.cpp b/src/modules/sway/workspaces.cpp
index e0255893..6abe5383 100644
--- a/src/modules/sway/workspaces.cpp
+++ b/src/modules/sway/workspaces.cpp
@@ -10,7 +10,7 @@ namespace waybar::modules::sway {
 
 // Helper function to assign a number to a workspace, just like sway. In fact
 // this is taken quite verbatim from `sway/ipc-json.c`.
-int Workspaces::convertWorkspaceNameToNum(std::string name) {
+int Workspaces::convertWorkspaceNameToNum(const std::string& name) {
   if (isdigit(name[0]) != 0) {
     errno = 0;
     char* endptr = nullptr;
@@ -487,7 +487,7 @@ std::string Workspaces::getCycleWorkspace(std::vector<Json::Value>::iterator it,
   return (*it)["name"].asString();
 }
 
-std::string Workspaces::trimWorkspaceName(std::string name) {
+std::string Workspaces::trimWorkspaceName(const std::string& name) {
   std::size_t found = name.find(':');
   if (found != std::string::npos) {
     return name.substr(found + 1);
diff --git a/src/modules/upower.cpp b/src/modules/upower.cpp
index 8202b718..d260ba83 100644
--- a/src/modules/upower.cpp
+++ b/src/modules/upower.cpp
@@ -95,7 +95,7 @@ UPower::~UPower() {
   removeDevices();
 }
 
-static const std::string getDeviceStatus(UpDeviceState& state) {
+static std::string_view getDeviceStatus(UpDeviceState& state) {
   switch (state) {
     case UP_DEVICE_STATE_CHARGING:
     case UP_DEVICE_STATE_PENDING_CHARGE:
@@ -112,7 +112,7 @@ static const std::string getDeviceStatus(UpDeviceState& state) {
   }
 }
 
-static const std::string getDeviceIcon(UpDeviceKind& kind) {
+static std::string_view getDeviceIcon(UpDeviceKind& kind) {
   switch (kind) {
     case UP_DEVICE_KIND_LINE_POWER:
       return "ac-adapter-symbolic";
@@ -212,7 +212,8 @@ auto UPower::update() -> void {
   // Remove last status if it exists
   if (!lastStatus_.empty() && box_.get_style_context()->has_class(lastStatus_))
     box_.get_style_context()->remove_class(lastStatus_);
-  if (!box_.get_style_context()->has_class(status)) box_.get_style_context()->add_class(status);
+  if (!box_.get_style_context()->has_class(std::string(status)))
+    box_.get_style_context()->add_class(std::string(status));
   lastStatus_ = status;
 
   if (devices_.size() == 0 && !upDeviceValid && hideIfEmpty_) {
diff --git a/src/util/gtk_icon.cpp b/src/util/gtk_icon.cpp
index 73f77284..1b2fca57 100644
--- a/src/util/gtk_icon.cpp
+++ b/src/util/gtk_icon.cpp
@@ -21,7 +21,6 @@ Glib::RefPtr<Gdk::Pixbuf> DefaultGtkIconThemeWrapper::load_icon(
   const std::lock_guard<std::mutex> lock(default_theme_mutex);
 
   auto default_theme = Gtk::IconTheme::get_default();
-  default_theme->rescan_if_needed();
 
   auto icon_info = default_theme->lookup_icon(name, tmp_size, flags);
 
diff --git a/test/utils/sleeper_thread.cpp b/test/utils/sleeper_thread.cpp
index 7a9a3ca1..9e1a1ef3 100644
--- a/test/utils/sleeper_thread.cpp
+++ b/test/utils/sleeper_thread.cpp
@@ -4,11 +4,12 @@
 #include <catch2/catch.hpp>
 #endif
 
-#include <chrono>
 #include <sys/wait.h>
-#include <thread>
 #include <unistd.h>
 
+#include <chrono>
+#include <thread>
+
 #include "util/sleeper_thread.hpp"
 
 namespace waybar::util {