refactor: modularize ev loop and improve error propagation

src/rendering/egl_context.rs

@@ -74,7 +74,7 @@ impl EGLContextBuilder {
             .ok_or_else(|| anyhow!("Surface ID is required"))?;
         let size = self.size.ok_or_else(|| anyhow!("Size is required"))?;
 
-        let display_handle = create_wayland_display_handle(&display_id);
+        let display_handle = create_wayland_display_handle(&display_id)?;
         let glutin_display = unsafe { Display::new(display_handle) }?;
 
         let config_template = self.config_template.unwrap_or_default();
@@ -85,7 +85,7 @@ impl EGLContextBuilder {
 
         let context = create_context(&glutin_display, &config, context_attributes)?;
 
-        let surface_handle = create_surface_handle(&surface_id);
+        let surface_handle = create_surface_handle(&surface_id)?;
         let surface = create_surface(&glutin_display, &config, surface_handle, size)?;
 
         let context = context
@@ -109,11 +109,11 @@ impl EGLContext {
     }
 }
 
-fn create_wayland_display_handle(display_id: &ObjectId) -> RawDisplayHandle {
+fn create_wayland_display_handle(display_id: &ObjectId) -> Result<RawDisplayHandle> {
     let display = NonNull::new(display_id.as_ptr().cast::<c_void>())
-        .expect("NonNull pointer creation failed");
+        .ok_or_else(|| anyhow!("Failed to create NonNull pointer for display"))?;
     let handle = WaylandDisplayHandle::new(display);
-    RawDisplayHandle::Wayland(handle)
+    Ok(RawDisplayHandle::Wayland(handle))
 }
 
 fn select_config(
@@ -134,11 +134,11 @@ fn create_context(
         .map_err(|e| anyhow!("Failed to create context: {}", e))
 }
 
-fn create_surface_handle(surface_id: &ObjectId) -> RawWindowHandle {
+fn create_surface_handle(surface_id: &ObjectId) -> Result<RawWindowHandle> {
     let surface = NonNull::new(surface_id.as_ptr().cast::<c_void>())
-        .expect("NonNull pointer creation failed");
+        .ok_or_else(|| anyhow!("Failed to create NonNull pointer for surface"))?;
     let handle = WaylandWindowHandle::new(surface);
-    RawWindowHandle::Wayland(handle)
+    Ok(RawWindowHandle::Wayland(handle))
 }
 
 fn create_surface(
@@ -147,11 +147,17 @@ fn create_surface(
     surface_handle: RawWindowHandle,
     size: PhysicalSize,
 ) -> Result<Surface<WindowSurface>> {
-    let attrs = SurfaceAttributesBuilder::<WindowSurface>::new().build(
+    let Some(width) = NonZeroU32::new(size.width) else {
-        surface_handle,
+        return Err(anyhow!("Width cannot be zero"));
-        NonZeroU32::new(size.width).unwrap(),
+    };
-        NonZeroU32::new(size.height).unwrap(),
+
-    );
+    let Some(height) = NonZeroU32::new(size.height) else {
+        return Err(anyhow!("Height cannot be zero"));
+    };
+
+    let attrs =
+        SurfaceAttributesBuilder::<WindowSurface>::new().build(surface_handle, width, height);
+
     unsafe { glutin_display.create_window_surface(config, &attrs) }
         .map_err(|e| anyhow!("Failed to create window surface: {}", e))
 }

src/rendering/femtovg_window.rs

@@ -1,3 +1,4 @@
+use anyhow::{anyhow, Result};
 use log::info;
 use slint::{
     platform::{femtovg_renderer::FemtoVGRenderer, Renderer, WindowAdapter, WindowEvent},
@@ -33,15 +34,16 @@ impl FemtoVGWindow {
         })
     }
 
-    pub fn render_frame_if_dirty(&self) {
+    pub fn render_frame_if_dirty(&self) -> Result<()> {
         if matches!(
             self.render_state.replace(RenderState::Clean),
             RenderState::Dirty
         ) {
-            if let Err(e) = self.renderer.render() {
+            self.renderer
-                log::error!("Error rendering frame: {}", e);
+                .render()
-            }
+                .map_err(|e| anyhow!("Error rendering frame: {}", e))?;
         }
+        Ok(())
     }
 
     pub fn set_scale_factor(&self, scale_factor: f32) {

src/windowing/mod.rs

@@ -1,14 +1,12 @@
 use self::state::WindowState;
 use crate::{
     bind_globals,
-    rendering::{
+    rendering::{egl_context::EGLContext, femtovg_window::FemtoVGWindow},
-        egl_context::EGLContext, femtovg_window::FemtoVGWindow, slint_platform::CustomSlintPlatform,
-    },
 };
 use anyhow::{Context, Result};
 use config::WindowConfig;
-use log::{debug, info};
+use log::{debug, error, info};
-use slint::{platform::femtovg_renderer::FemtoVGRenderer, ComponentHandle, LogicalPosition};
+use slint::{platform::femtovg_renderer::FemtoVGRenderer, LogicalPosition};
 use slint_interpreter::ComponentInstance;
 use smithay_client_toolkit::reexports::{
     calloop::{self, EventLoop, Interest, LoopHandle, Mode, PostAction},
@@ -49,7 +47,7 @@ impl WindowingSystem {
         let (compositor, output, layer_shell, seat) =
             Self::bind_globals(&global_list, &event_queue.handle())?;
 
-        let mut state = WindowState::new(config);
+        let mut state = WindowState::new(config)?;
 
         Self::setup_surface(
             &compositor,
@@ -164,7 +162,9 @@ impl WindowingSystem {
 
     fn create_renderer(state: &WindowState, display: &WlDisplay) -> Result<FemtoVGRenderer> {
         let size = state.size();
-        let surface = state.surface().unwrap();
+        let surface = state
+            .surface()
+            .ok_or_else(|| anyhow::anyhow!("Failed to get surface"))?;
 
         debug!("Creating EGL context with size: {:?}", size);
         let context = EGLContext::builder()
@@ -205,48 +205,83 @@ impl WindowingSystem {
 
     pub fn run(&mut self) -> Result<()> {
         info!("Starting WindowingSystem main loop");
-        if let Some(window) = &self.state.window() {
+
-            window.render_frame_if_dirty();
+        self.initialize_component()?;
-        }
+        self.setup_wayland_event_source()?;
-        self.state.show_component()?;
+
-        self.setup_wayland_event_source();
+        let connection = Rc::clone(&self.connection);
+        let event_queue = &mut self.event_queue;
 
         self.event_loop
-            .run(None, &mut self.state, |shared_data| {
+            .run(None, &mut self.state, move |shared_data| {
-                let _ = self.connection.flush();
+                if let Err(e) =
-                if let Some(guard) = self.event_queue.prepare_read() {
+                    Self::process_events(&Rc::clone(&connection), event_queue, shared_data)
-                    let _ = guard.read();
+                {
+                    error!("Error processing events: {}", e);
                 }
-
-                let _ = self.event_queue.dispatch_pending(shared_data);
-
-                slint::platform::update_timers_and_animations();
-                shared_data
-                    .window()
-                    .as_ref()
-                    .unwrap()
-                    .render_frame_if_dirty();
             })
             .map_err(|e| anyhow::anyhow!("Failed to run event loop: {}", e))
     }
 
-    pub fn setup_wayland_event_source(&self) {
+    fn initialize_component(&mut self) -> Result<()> {
+        if let Some(window) = &self.state.window() {
+            window.render_frame_if_dirty()?;
+        } else {
+            return Err(anyhow::anyhow!("Window not initialized"));
+        }
+
+        self.state.show_component()?;
+        Ok(())
+    }
+
+    fn setup_wayland_event_source(&self) -> Result<()> {
         debug!("Setting up Wayland event source");
 
         let connection = Rc::clone(&self.connection);
 
-        let _ = self.event_loop.handle().insert_source(
+        self.event_loop
-            calloop::generic::Generic::new(connection, Interest::READ, Mode::Level),
+            .handle()
-            move |_, _connection, _shared_data| Ok(PostAction::Continue),
+            .insert_source(
-        );
+                calloop::generic::Generic::new(connection, Interest::READ, Mode::Level),
+                move |_, _connection, _shared_data| Ok(PostAction::Continue),
+            )
+            .map_err(|e| anyhow::anyhow!("Failed to set up Wayland event source: {}", e))?;
+
+        Ok(())
     }
 
-    pub fn component_instance(&self) -> &ComponentInstance {
+    fn process_events(
+        connection: &Rc<Connection>,
+        event_queue: &mut EventQueue<WindowState>,
+        shared_data: &mut WindowState,
+    ) -> Result<()> {
+        connection.flush()?;
+
+        if let Some(guard) = event_queue.prepare_read() {
+            guard
+                .read()
+                .map_err(|e| anyhow::anyhow!("Failed to read events: {}", e))?;
+        }
+
+        event_queue.dispatch_pending(shared_data)?;
+
+        slint::platform::update_timers_and_animations();
+
+        if let Some(window) = shared_data.window() {
+            window.render_frame_if_dirty()?;
+        } else {
+            return Err(anyhow::anyhow!("Window not initialized"));
+        }
+
+        Ok(())
+    }
+
+    pub const fn component_instance(&self) -> Option<&ComponentInstance> {
         self.state.component_instance()
     }
 
-    pub fn window(&self) -> Rc<FemtoVGWindow> {
+    pub fn window(&self) -> Option<Rc<FemtoVGWindow>> {
-        Rc::clone(self.state().window().as_ref().unwrap())
+        self.state().window().as_ref().map(Rc::clone)
     }
 
     pub const fn state(&self) -> &WindowState {

src/windowing/state/dispatches.rs

@@ -1,5 +1,5 @@
 use crate::impl_empty_dispatch;
-use log::info;
+use log::{info, warn};
 use slint::{
     platform::{PointerEventButton, WindowEvent},
     PhysicalSize,
@@ -42,10 +42,20 @@ impl Dispatch<ZwlrLayerSurfaceV1, ()> for WindowState {
                 info!("Layer surface configured with size: {}x{}", width, height);
                 layer_surface.ack_configure(serial);
                 if width > 0 && height > 0 {
-                    state.update_size(state.output_size().width, state.height());
+                    state
+                        .update_size(state.output_size().width, state.height())
+                        .unwrap_or(warn!(
+                            "Failed to update window size with width: {} and height: {}",
+                            width, height
+                        ));
                 } else {
                     let current_size = state.output_size();
-                    state.update_size(current_size.width, current_size.height);
+                    state
+                        .update_size(current_size.width, current_size.height)
+                        .unwrap_or(warn!(
+                            "Failed to update window size with width: {} and height: {}",
+                            width, height
+                        ));
                 }
             }
             zwlr_layer_surface_v1::Event::Closed => {

src/windowing/state/mod.rs

@@ -1,4 +1,4 @@
-use std::{rc::Rc};
+use std::rc::Rc;
 use log::info;
 use slint::{LogicalPosition, PhysicalSize, ComponentHandle};
 use slint_interpreter::{ComponentDefinition, ComponentInstance};
@@ -26,8 +26,13 @@ pub struct WindowState {
 }
 
 impl WindowState {
-    pub fn new(config: &mut WindowConfig) -> Self {
+    pub fn new(config: &mut WindowConfig) -> Result<Self> {
-        Self {
+        let component_definition = config
+            .component_definition
+            .take()
+            .ok_or_else(|| anyhow::anyhow!("Component definition is required"))?;
+
+        Ok(Self {
             surface: None,
             layer_surface: None,
             size: PhysicalSize::default(),
@@ -38,9 +43,9 @@ impl WindowState {
             scale_factor: config.scale_factor,
             height: config.height,
             exclusive_zone: config.exclusive_zone,
-            component_definition: config.component_definition.take().unwrap(),
+            component_definition,
             component_instance: None,
-        }
+        })
     }
 
     pub fn show_component(&mut self) -> Result<()> {
@@ -52,11 +57,16 @@ impl WindowState {
 
         self.component_instance = Some(self.component_definition.create()?);
 
-        self.component_instance.as_ref().unwrap().show()?;
+        if let Some(component_instance) = &self.component_instance {
+            component_instance.show()?;
+        } else {
+            return Err(anyhow::anyhow!("Component instance not initialized"));
+        }
+
         Ok(())
     }
 
-    pub fn update_size(&mut self, width: u32, height: u32) {
+    pub fn update_size(&mut self, width: u32, height: u32) -> Result<()> {
         let new_size = PhysicalSize::new(width, height);
         if let Some(window) = &self.window() {
             info!("Updating window size to {}x{}", width, height);
@@ -70,10 +80,14 @@ impl WindowState {
             layer_surface.set_exclusive_zone(self.exclusive_zone);
         }
 
-        if let Some(s) = self.surface.as_ref() {
+        match self.surface.as_ref() {
-            s.commit();
+            Some(surface) => surface.commit(),
+            None => {
+                return Err(anyhow::anyhow!("Surface not initialized"));
+            }
         }
         self.size = new_size;
+        Ok(())
     }
 
     pub fn set_current_pointer_position(&mut self, physical_x: f64, physical_y: f64) {
@@ -130,7 +144,7 @@ impl WindowState {
         self.pointer = Some(pointer);
     }
 
-    pub fn component_instance(&self) -> &ComponentInstance {
+    pub const fn component_instance(&self) -> Option<&ComponentInstance> {
-        self.component_instance.as_ref().unwrap()
+        self.component_instance.as_ref()
     }
 }