feat: proper error handling

Cargo.toml

@@ -6,5 +6,6 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-winit = "0.29.1-beta"
+eyre = "0.6.8"
 softbuffer = "0.3.1"
+winit = "0.29.1-beta"

src/main.rs

@@ -1,76 +1,100 @@
 use std::num::NonZeroU32;
 
+use eyre::{format_err, Result, WrapErr};
 use winit::{
+    dpi::PhysicalSize,
     event::{Event, WindowEvent},
     event_loop::{ControlFlow, EventLoop},
-    window::Window, dpi::PhysicalSize,
+    window::Window,
 };
 
 struct State {
     // reverse order is important for safety (though I doubt anyone cares at exit)
     surface: softbuffer::Surface,
-    context: softbuffer::Context,
+    _context: softbuffer::Context,
     window: Window,
 }
 
 impl State {
-    pub fn new(event_loop: &EventLoop<()>) -> Self {
-        let window = Window::new(event_loop).unwrap();
+    pub fn new(event_loop: &EventLoop<()>) -> Result<Self> {
+        let window = Window::new(event_loop).wrap_err("while creating window")?;
 
         // SAFETY: window is only dropped at the end of the struct
-        let context = unsafe { softbuffer::Context::new(&window) }.unwrap();
-        let surface = unsafe { softbuffer::Surface::new(&context, &window) }.unwrap();
+        // can't use wrap_err since softbuffer's error is neither send nor sync
+        let context = unsafe { softbuffer::Context::new(&window) }
+            .map_err(|e| format_err!("while creating softbuffer context: {e}"))?;
+        let surface = unsafe { softbuffer::Surface::new(&context, &window) }
+            .map_err(|e| format_err!("while creating surface: {e}"))?;
 
         let mut state = Self {
             surface,
-            context,
+            _context: context,
             window,
         };
 
         // initial resize needed for the surface to configure itself
         let initial_size = state.window.inner_size();
-        state.resize(initial_size);
+        state.resize(initial_size)?;
 
-        state
+        Ok(state)
     }
 
-    pub fn process(&mut self, event: Event<()>) -> ControlFlow {
+    pub fn process(&mut self, event: Event<()>) -> Result<ControlFlow> {
         match event {
-            Event::RedrawRequested(_) => self.draw(),
+            Event::RedrawRequested(_) => self.draw()?,
             Event::WindowEvent { event, .. } => match event {
-                WindowEvent::Resized(new_size) => self.resize(new_size),
-                WindowEvent::CloseRequested => return ControlFlow::Exit,
+                WindowEvent::Resized(new_size) => self.resize(new_size)?,
+                WindowEvent::CloseRequested => return Ok(ControlFlow::Exit),
                 _ => (),
-            }
+            },
             _ => (),
         }
 
-        ControlFlow::Wait
+        Ok(ControlFlow::Wait)
     }
 
-    pub fn resize(&mut self, new_size: PhysicalSize<u32>) {
-        let (width, height) = (
-            NonZeroU32::new(new_size.width).unwrap(),
-            NonZeroU32::new(new_size.height).unwrap(),
-        );
-        self.surface.resize(width, height).unwrap();
+    pub fn resize(&mut self, new_size: PhysicalSize<u32>) -> Result<()> {
+        let Some(width) = NonZeroU32::new(new_size.width) else {
+            // probably minimized, won't be drawn then anyway
+            return Ok(());
+        };
+        let Some(height) = NonZeroU32::new(new_size.height) else {
+            return Ok(());
+        };
+
+        self.surface
+            .resize(width, height)
+            .map_err(|e| format_err!("could not resize surface: {e}"))
     }
 
-    pub fn draw(&mut self) {
-        let mut buffer = self.surface.buffer_mut().unwrap();
+    pub fn draw(&mut self) -> Result<()> {
+        let mut buffer = self
+            .surface
+            .buffer_mut()
+            .map_err(|e| format_err!("could not get reference to display buffer: {e}"))?;
 
         let light_color = (255 << 16) | (255 << 8) | 255;
         buffer.fill(light_color);
 
-        buffer.present().unwrap();
+        buffer
+            .present()
+            .map_err(|e| format_err!("could not present display buffer: {e}"))
     }
 }
 
-fn main() -> Result<(), winit::error::EventLoopError> {
-    let event_loop = EventLoop::new().unwrap();
-    let mut state = State::new(&event_loop);
+fn main() -> Result<()> {
+    let event_loop = EventLoop::new().wrap_err("while creating event loop")?;
+    let mut state = State::new(&event_loop).wrap_err("while creating state")?;
 
-    event_loop.run(move |event, _, flow| {
-        *flow = state.process(event);
-    })
+    event_loop
+        .run(move |event, _, flow| {
+            *flow = match state.process(event) {
+                Ok(flow) => flow,
+                Err(e) => {
+                    eprintln!("error: {e}");
+                    ControlFlow::Exit
+                }
+            }
+        })
+        .wrap_err("while running event loop")
 }