feat(dependencies): gate ddcutil via DependencyService across settings etc

assets/translations/en.json

@@ -1464,7 +1464,8 @@
         },
         "ddcutil": {
           "label": "DDC/CI (ddcutil)",
-          "description": "Control external monitor brightness via DDC/CI"
+          "description": "Control external monitor brightness via DDC/CI",
+          "requires-ddcutil": "Install ddcutil to enable DDC/CI brightness control"
         },
         "night-light": {
           "label": "Night Light",

src/app/application.cpp

@@ -578,8 +578,8 @@ void Application::initServices() {
   }
 
   try {
-    m_brightnessService =
-        std::make_unique<BrightnessService>(m_systemBus.get(), m_wayland, m_configService.config().brightness);
+    m_brightnessService = std::make_unique<BrightnessService>(
+        m_systemBus.get(), m_wayland, m_configService.config().brightness, &m_dependencyService);
     m_brightnessService->setChangeCallback([this, shouldRefreshControlCenter]() {
       m_brightnessOsd.onBrightnessChanged(*m_brightnessService);
       m_bar.refresh();

src/shell/control_center/control_center_panel.cpp

@@ -1,10 +1,12 @@
 #include "shell/control_center/control_center_panel.h"
 
+#include "config/config_service.h"
 #include "i18n/i18n.h"
 #include "notification/notification_manager.h"
 #include "render/core/renderer.h"
 #include "render/scene/input_area.h"
 #include "shell/panel/panel_manager.h"
+#include "system/brightness_service.h"
 #include "system/dependency_service.h"
 #include "ui/controls/button.h"
 #include "ui/controls/flex.h"
@@ -22,6 +24,8 @@ ControlCenterPanel::ControlCenterPanel(
     SystemMonitorService* sysmon, NightLightManager* nightLight, noctalia::theme::ThemeService* theme,
     IdleInhibitor* idleInhibitor, DependencyService* dependencies, WaylandConnection* wayland, Wallpaper* wallpaper) {
   (void)upower;
+  m_config = config;
+  m_brightness = brightness;
   m_notificationManager = notifications;
   m_dependencies = dependencies;
   m_tabs[tabIndex(TabId::Overview)] =
@@ -243,6 +247,9 @@ void ControlCenterPanel::onOpen(std::string_view context) {
   if (m_dependencies != nullptr) {
     m_dependencies->rescan();
   }
+  if (m_brightness != nullptr && m_config != nullptr) {
+    m_brightness->reload(m_config->config().brightness);
+  }
   selectTab(tabFromContext(context));
 }
 

src/shell/control_center/control_center_panel.h

@@ -135,6 +135,8 @@ private:
   std::array<Flex*, kTabCount> m_tabContainers{};
   std::array<Flex*, kTabCount> m_tabHeaderActions{};
   TabId m_activeTab = TabId::Overview;
+  ConfigService* m_config = nullptr;
+  BrightnessService* m_brightness = nullptr;
   NotificationManager* m_notificationManager = nullptr;
   DependencyService* m_dependencies = nullptr;
 };

src/shell/settings/settings_registry.cpp

@@ -620,8 +620,11 @@ namespace settings {
                                 {"shell", "mpris", "blacklist"}, ListSetting{.items = cfg.shell.mpris.blacklist},
                                 "mpris media player dbus session blacklist"));
     entries.push_back(makeEntry("services", "brightness", tr("settings.schema.services.ddcutil.label"),
-                                tr("settings.schema.services.ddcutil.description"), {"brightness", "enable_ddcutil"},
-                                ToggleSetting{cfg.brightness.enableDdcutil}, "monitor ddcutil"));
+                                env.ddcutilAvailable ? tr("settings.schema.services.ddcutil.description")
+                                                     : tr("settings.schema.services.ddcutil.requires-ddcutil"),
+                                {"brightness", "enable_ddcutil"},
+                                ToggleSetting{.checked = cfg.brightness.enableDdcutil, .enabled = env.ddcutilAvailable},
+                                "monitor ddcutil"));
     if (!env.wlsunsetAvailable) {
       // Show only the master toggle in a disabled state so users can discover the feature
       // and learn the dependency requirement. The remaining settings are hidden until wlsunset is installed.

src/shell/settings/settings_registry.h

@@ -111,6 +111,7 @@ namespace settings {
   // Runtime conditions that gate optional sections (e.g. compositor-specific features).
   struct RegistryEnvironment {
     bool niriBackdropSupported = false;         // hide the [backdrop] section when false
+    bool ddcutilAvailable = false;              // disable ddcutil toggle when ddcutil is not on PATH
     bool wlsunsetAvailable = false;             // hide night-light entries when wlsunset is not on PATH
     std::vector<SelectOption> availableOutputs; // monitor selectors available on this machine
     std::vector<SelectOption> communityPalettes;

src/shell/settings/settings_window.cpp

@@ -948,6 +948,7 @@ void SettingsWindow::buildScene(std::uint32_t width, std::uint32_t height) {
   }
   settings::RegistryEnvironment env;
   env.niriBackdropSupported = (m_wayland != nullptr && compositors::isNiri());
+  env.ddcutilAvailable = (m_dependencies != nullptr && m_dependencies->hasDdcutil());
   env.wlsunsetAvailable = (m_dependencies != nullptr && m_dependencies->hasWlsunset());
   for (const auto& paletteInfo : noctalia::theme::availableCommunityPalettes()) {
     env.communityPalettes.push_back(settings::SelectOption{paletteInfo.name, paletteInfo.name});

src/system/brightness_service.cpp

@@ -2,11 +2,11 @@
 
 #include "config/config_service.h"
 #include "core/log.h"
-#include "core/process.h"
 #include "core/timer_manager.h"
 #include "dbus/system_bus.h"
 #include "ipc/ipc_arg_parse.h"
 #include "ipc/ipc_service.h"
+#include "system/dependency_service.h"
 #include "wayland/wayland_connection.h"
 
 #include <algorithm>
@@ -586,6 +586,7 @@ namespace {
 struct BrightnessService::Impl {
   SystemBus* bus = nullptr;
   WaylandConnection& wayland;
+  DependencyService* dependencies = nullptr;
   BrightnessConfig activeConfig;
   ChangeCallback changeCallback;
 
@@ -613,8 +614,8 @@ struct BrightnessService::Impl {
   std::unordered_map<std::string, DdcJob> pendingRefreshes;
   std::queue<WorkerCompletion> completions;
 
-  Impl(SystemBus* systemBus, WaylandConnection& wl, const BrightnessConfig& config)
-      : bus(systemBus), wayland(wl), activeConfig(config) {
+  Impl(SystemBus* systemBus, WaylandConnection& wl, const BrightnessConfig& config, DependencyService* deps)
+      : bus(systemBus), wayland(wl), dependencies(deps), activeConfig(config) {
     setupPollFds();
     workerThread = std::thread([this]() { workerLoop(); });
   }
@@ -816,7 +817,7 @@ struct BrightnessService::Impl {
     if (!activeConfig.enableDdcutil) {
       return;
     }
-    if (!process::commandExists("ddcutil")) {
+    if (dependencies != nullptr && !dependencies->hasDdcutil()) {
       if (!warnedMissingDdcutil) {
         kLog.warn("brightness.enable_ddcutil is set but ddcutil is not installed");
         warnedMissingDdcutil = true;
@@ -1307,8 +1308,9 @@ struct BrightnessService::Impl {
   }
 };
 
-BrightnessService::BrightnessService(SystemBus* bus, WaylandConnection& wayland, const BrightnessConfig& config)
-    : m_impl(new Impl(bus, wayland, config)) {
+BrightnessService::BrightnessService(SystemBus* bus, WaylandConnection& wayland, const BrightnessConfig& config,
+                                     DependencyService* dependencies)
+    : m_impl(new Impl(bus, wayland, config, dependencies)) {
   m_impl->rebuildState(false);
 }
 

src/system/brightness_service.h

@@ -6,6 +6,7 @@
 #include <vector>
 
 class IpcService;
+class DependencyService;
 class SystemBus;
 class WaylandConnection;
 struct BrightnessConfig;
@@ -29,7 +30,8 @@ class BrightnessService {
 public:
   using ChangeCallback = std::function<void()>;
 
-  BrightnessService(SystemBus* bus, WaylandConnection& wayland, const BrightnessConfig& config);
+  BrightnessService(SystemBus* bus, WaylandConnection& wayland, const BrightnessConfig& config,
+                    DependencyService* dependencies = nullptr);
   ~BrightnessService();
 
   BrightnessService(const BrightnessService&) = delete;

src/system/dependency_service.cpp

@@ -11,7 +11,8 @@ namespace {
   constexpr Logger kLog("dependencies");
 
   // Optional CLI tools the shell knows about. Adding a new tracked tool is one line.
-  constexpr std::array<const char*, 1> kTrackedTools = {
+  constexpr std::array<const char*, 2> kTrackedTools = {
+      "ddcutil",
       "wlsunset",
   };
 

src/system/dependency_service.h

@@ -9,6 +9,7 @@ public:
   DependencyService();
 
   [[nodiscard]] bool has(std::string_view name) const;
+  [[nodiscard]] bool hasDdcutil() const { return has("ddcutil"); }
   [[nodiscard]] bool hasWlsunset() const { return has("wlsunset"); }
 
   void rescan();