Update status from pipe

src/bar.cpp

@@ -13,6 +13,13 @@ const zwlr_layer_surface_v1_listener Bar::_layerSurfaceListener = {
         static_cast<Bar*>(owner)->layerSurfaceConfigure(serial, width, height);
     }
 };
+const wl_callback_listener Bar::_frameListener = {
+    [](void *owner, wl_callback *cb, uint32_t)
+    {
+        static_cast<Bar*>(owner)->render();
+        wl_callback_destroy(cb);
+    }
+};
 
 static QFont getFont()
 {
@@ -53,6 +60,21 @@ Bar::~Bar()
     zwlr_layer_surface_v1_destroy(_layerSurface);
 }
 
+void Bar::invalidate()
+{
+    if (_invalid) return;
+    _invalid = true;
+    auto frame = wl_surface_frame(_surface);
+    wl_callback_add_listener(frame, &_frameListener, this);
+    wl_surface_commit(_surface);
+}
+
+void Bar::setStatus(const QString &status)
+{
+    _status = status;
+    invalidate();
+}
+
 void Bar::layerSurfaceConfigure(uint32_t serial, uint32_t width, uint32_t height)
 {
     zwlr_layer_surface_v1_ack_configure(_layerSurface, serial);
@@ -83,8 +105,10 @@ void Bar::render()
     
     _painter = nullptr;
     wl_surface_attach(_surface, _bufs->buffer(), 0, 0);
+    wl_surface_damage(_surface, 0, 0, INT_MAX, INT_MAX);
     wl_surface_commit(_surface);
     _bufs->flip();
+    _invalid = false;
 }
 
 void Bar::setColorScheme(const ColorScheme &scheme)

src/bar.hpp

@@ -19,6 +19,7 @@ struct Tag {
 
 class Bar {
     static const zwlr_layer_surface_v1_listener _layerSurfaceListener;
+    static const wl_callback_listener _frameListener;
 
     wl_surface *_surface {nullptr};
     zwlr_layer_surface_v1 *_layerSurface {nullptr};
@@ -27,6 +28,7 @@ class Bar {
     QFontMetrics _fontMetrics;
     std::optional<ShmBuffer> _bufs;
     int _textY, _x;
+    bool _invalid {false};
 
     std::vector<Tag> _tags;
     QString _windowTitle;
@@ -39,7 +41,9 @@ class Bar {
     void renderText(const QString &text);
     int textWidth(const QString &text);
     void setColorScheme(const ColorScheme &scheme);
+    void invalidate();
 public:
     explicit Bar(const wl_output *output);
+    void setStatus(const QString &status);
     ~Bar();
 };

src/main.cpp

@@ -9,6 +9,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
+#include <optional>
 #include <QGuiApplication>
 #include <QSocketNotifier>
 #include <wayland-client.h>
@@ -28,6 +29,7 @@ wl_display *display;
 wl_compositor *compositor;
 wl_shm *shm;
 zwlr_layer_shell_v1 *wlrLayerShell;
+static std::optional<Bar> bar;
 static std::string statusFifoName;
 static int statusFifoFd {-1};
 static int statusFifoWriter {-1};
@@ -48,7 +50,7 @@ static void onReady()
     requireGlobal(shm, "wl_shm");
     requireGlobal(wlrLayerShell, "zwlr_layer_shell_v1");
     setupStatusFifo();
-    std::ignore = new Bar(nullptr);
+    bar.emplace(nullptr);
 }
 
 static void setupStatusFifo()
@@ -89,6 +91,9 @@ static void onStatus()
     char buffer[512];
     auto n = read(statusFifoFd, buffer, sizeof(buffer));
     auto str = QString::fromUtf8(buffer, n);
+    if (bar) {
+        bar->setStatus(str);
+    }
 }
 
 struct HandleGlobalHelper {