perf(memory): optimize C++ string operations to reduce heap fragmentation

- Replaced pass-by-value std::string parameters with const std::string&
or std::string_view to prevent SSO overallocations.

- Refactored static mapping functions in UPower to return
std::string_view instead of constructing std::string literals, enabling
perfect cache locality.

- Optimized string concatenation in hot loops (network IPs, inhibitor
lists, sway window marks) by using std::string::append() and
pre-reserving capacity instead of overloaded operator+ which produces
temporary heap instances.

These optimizations reduce high-frequency memory churn and overall heap
fragmentation within the main rendering loops.

Signed-off-by: Austin Horstman <khaneliman12@gmail.com>

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

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();

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);
 

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&);

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_;

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_;

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;

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_;

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>

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);
     });
   }