Change create_custom_cursor() to return Result (#3844)

src/platform_impl/windows/event_loop.rs

@@ -58,7 +58,7 @@ use super::window::set_skip_taskbar;
 use super::SelectedCursor;
 use crate::application::ApplicationHandler;
 use crate::dpi::{PhysicalPosition, PhysicalSize};
-use crate::error::EventLoopError;
+use crate::error::{EventLoopError, ExternalError};
 use crate::event::{
     Event, Force, Ime, InnerSizeWriter, RawKeyEvent, Touch, TouchPhase, WindowEvent,
 };
@@ -483,16 +483,11 @@ impl ActiveEventLoop {
         EventLoopThreadExecutor { thread_id: self.thread_id, target_window: self.thread_msg_target }
     }
 
-    pub fn create_custom_cursor(&self, source: CustomCursorSource) -> RootCustomCursor {
-        let inner = match WinCursor::new(&source.inner.0) {
-            Ok(cursor) => cursor,
-            Err(err) => {
-                tracing::warn!("Failed to create custom cursor: {err}");
-                WinCursor::Failed
-            },
-        };
-
-        RootCustomCursor { inner }
+    pub fn create_custom_cursor(
+        &self,
+        source: CustomCursorSource,
+    ) -> Result<RootCustomCursor, ExternalError> {
+        Ok(RootCustomCursor { inner: WinCursor::new(&source.inner.0)? })
     }
 
     // TODO: Investigate opportunities for caching

src/platform_impl/windows/icon.rs

@@ -17,6 +17,7 @@ use windows_sys::Win32::UI::WindowsAndMessaging::{
 use super::util;
 use crate::cursor::CursorImage;
 use crate::dpi::PhysicalSize;
+use crate::error::ExternalError;
 use crate::icon::*;
 
 impl Pixel {
@@ -175,13 +176,10 @@ impl Default for SelectedCursor {
 }
 
 #[derive(Clone, Debug, Hash, Eq, PartialEq)]
-pub enum WinCursor {
-    Cursor(Arc<RaiiCursor>),
-    Failed,
-}
+pub struct WinCursor(pub(super) Arc<RaiiCursor>);
 
 impl WinCursor {
-    pub(crate) fn new(image: &CursorImage) -> Result<Self, io::Error> {
+    pub(crate) fn new(image: &CursorImage) -> Result<Self, ExternalError> {
         let mut bgra = image.rgba.clone();
         bgra.chunks_exact_mut(4).for_each(|chunk| chunk.swap(0, 2));
 
@@ -191,16 +189,16 @@ impl WinCursor {
         unsafe {
             let hdc_screen = GetDC(0);
             if hdc_screen == 0 {
-                return Err(io::Error::last_os_error());
+                return Err(ExternalError::Os(os_error!(io::Error::last_os_error())));
             }
             let hbm_color = CreateCompatibleBitmap(hdc_screen, w, h);
             ReleaseDC(0, hdc_screen);
             if hbm_color == 0 {
-                return Err(io::Error::last_os_error());
+                return Err(ExternalError::Os(os_error!(io::Error::last_os_error())));
             }
             if SetBitmapBits(hbm_color, bgra.len() as u32, bgra.as_ptr() as *const c_void) == 0 {
                 DeleteObject(hbm_color);
-                return Err(io::Error::last_os_error());
+                return Err(ExternalError::Os(os_error!(io::Error::last_os_error())));
             };
 
             // Mask created according to https://learn.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createbitmap#parameters
@@ -208,7 +206,7 @@ impl WinCursor {
             let hbm_mask = CreateBitmap(w, h, 1, 1, mask_bits.as_ptr() as *const _);
             if hbm_mask == 0 {
                 DeleteObject(hbm_color);
-                return Err(io::Error::last_os_error());
+                return Err(ExternalError::Os(os_error!(io::Error::last_os_error())));
             }
 
             let icon_info = ICONINFO {
@@ -223,10 +221,10 @@ impl WinCursor {
             DeleteObject(hbm_color);
             DeleteObject(hbm_mask);
             if handle == 0 {
-                return Err(io::Error::last_os_error());
+                return Err(ExternalError::Os(os_error!(io::Error::last_os_error())));
             }
 
-            Ok(Self::Cursor(Arc::new(RaiiCursor { handle })))
+            Ok(Self(Arc::new(RaiiCursor { handle })))
         }
     }
 }

src/platform_impl/windows/window.rs

@@ -59,7 +59,7 @@ use crate::platform_impl::platform::dpi::{
 };
 use crate::platform_impl::platform::drop_handler::FileDropHandler;
 use crate::platform_impl::platform::event_loop::{self, ActiveEventLoop, DESTROY_MSG_ID};
-use crate::platform_impl::platform::icon::{self, IconType, WinCursor};
+use crate::platform_impl::platform::icon::{self, IconType};
 use crate::platform_impl::platform::ime::ImeContext;
 use crate::platform_impl::platform::keyboard::KeyEventBuilder;
 use crate::platform_impl::platform::monitor::{self, MonitorHandle};
@@ -383,17 +383,10 @@ impl Window {
                 });
             },
             Cursor::Custom(cursor) => {
-                let new_cursor = match cursor.inner {
-                    WinCursor::Cursor(cursor) => cursor,
-                    WinCursor::Failed => {
-                        warn!("Requested to apply failed cursor");
-                        return;
-                    },
-                };
                 self.window_state_lock().mouse.selected_cursor =
-                    SelectedCursor::Custom(new_cursor.clone());
+                    SelectedCursor::Custom(cursor.inner.0.clone());
                 self.thread_executor.execute_in_thread(move || unsafe {
-                    SetCursor(new_cursor.as_raw_handle());
+                    SetCursor(cursor.inner.0.as_raw_handle());
                 });
             },
         }