nixos: Prevent xochitl from running concurrently

Author: timower

apps/rocket/Hideable.h

@@ -65,8 +65,8 @@ class HideableRenderObject
     auto result = this->child->draw(canvas, { 0, 0 });
     if (doRefresh) {
       doRefresh = false;
-      result.waveform = rmlib::fb::Waveform::GC16;
-      result.flags = rmlib::fb::UpdateFlags::FullRefresh;
+      result.waveform = rmlib::fb::Waveform::GC16Fast;
+      // result.flags = rmlib::fb::UpdateFlags::FullRefresh;
     }
 
     return result;

apps/rocket/Launcher.cpp

@@ -221,6 +221,7 @@ LauncherState::tick() const {
 
 void
 LauncherState::toggle(rmlib::AppContext& context) {
+  background.reset();
   if (visible) {
     bool shouldStartTimer = sleepCountdown <= 0;
     stopTimer();
@@ -237,8 +238,6 @@ LauncherState::show() {
     return;
   }
 
-  background.reset();
-
   if (auto err = getWidget().ctlClient.switchTo(getpid()); !err) {
     std::cerr << "Error switching: " << to_string(err.error()) << "\n";
   }
@@ -270,7 +269,7 @@ LauncherState::switchApp(pid_t pid) {
 }
 
 void
-LauncherState::launch(App& app) {
+LauncherState::launch(rmlib::AppContext& ctx, App& app) {
   stopTimer();
 
   if (!app.launch()) {
@@ -280,6 +279,8 @@ LauncherState::launch(App& app) {
 
   if (auto icon = app.icon(); icon.has_value()) {
     background = *icon;
+    backgroundTimer = ctx.addTimer(std::chrono::seconds(3),
+                                   [this] { modify().background.reset(); });
   }
 }
 
@@ -295,9 +296,9 @@ LauncherState::onSignal() {
   if (*sigOrErr == SIGUSR1) {
     stopTimer();
     visible = false;
+    background.reset();
   } else if (*sigOrErr == SIGCONT) {
     visible = true;
-    background.reset();
 
     readApps();
     requestClients();

apps/rocket/Launcher.h

@@ -102,15 +102,15 @@ class LauncherState : public rmlib::StateBase<LauncherWidget> {
     return Wrap(widgets);
   }
 
-  auto appList() const {
+  auto appList(rmlib::AppContext& ctx) const {
     using namespace rmlib;
 
     std::vector<AppWidget> widgets;
     for (const auto& app : apps) {
       if (!isRunning(app.getLaunchPid())) {
-        widgets.emplace_back(app, [this, &app] {
+        widgets.emplace_back(app, [this, &app, &ctx] {
           setState(
-            [&app](auto& self) { self.launch(*const_cast<App*>(&app)); });
+            [&](auto& self) { self.launch(ctx, *const_cast<App*>(&app)); });
         });
       }
     }
@@ -120,7 +120,7 @@ class LauncherState : public rmlib::StateBase<LauncherWidget> {
   auto launcher(rmlib::AppContext& context) const {
     using namespace rmlib;
 
-    return Cleared(Column(header(context), runningApps(), appList()));
+    return Cleared(Column(header(context), runningApps(), appList(context)));
   }
 
   auto build(rmlib::AppContext& context,
@@ -165,7 +165,7 @@ class LauncherState : public rmlib::StateBase<LauncherWidget> {
   void hide(rmlib::AppContext* context);
   void toggle(rmlib::AppContext& context);
 
-  void launch(App& app);
+  void launch(rmlib::AppContext& ctx, App& app);
   void switchApp(pid_t pid);
 
   void onSignal();
@@ -185,6 +185,7 @@ class LauncherState : public rmlib::StateBase<LauncherWidget> {
 
   rmlib::TimerHandle sleepTimer;
   rmlib::TimerHandle inactivityTimer;
+  rmlib::TimerHandle backgroundTimer;
 
   rmlib::Rotation rotation = rmlib::Rotation::None;
   std::optional<rmlib::Canvas> background;

nix/modules/xochitl.nix

@@ -10,8 +10,17 @@ let
   };
   xochitl = pkgs.writeShellApplication {
     name = "xochitl";
-    runtimeInputs = [ pkgs.systemd ];
+    runtimeInputs = with pkgs; [
+      systemd
+      util-linux
+    ];
     text = ''
+      exec {fd}>"''${XDG_RUNTIME_DIR:-/run}/xochitl.lock"
+      if ! flock -n -x $fd; then
+        echo "Only one xochitl supported!"
+        exit 1
+      fi
+
       ctlCmd="systemctl"
       if [ "$EUID" -ne "0" ]; then
         ctlCmd="systemctl --user"