Re-work event loop run() API so it can return a Result

This re-works the portable `run()` API that consumes the `EventLoop` and runs the loop on the calling thread until the app exits. This can be supported across _all_ platforms and compared to the previous `run() -> !` API is now able to return a `Result` status on all platforms except iOS and Web. Fixes: rust-windowing#2709 By moving away from `run() -> !` we stop calling `std::process::exit()` internally as a means to kill the process without returning which means it's possible to return an exit status and applications can return from their `main()` function normally. This also fixes Android support where an Activity runs in a thread but we can't assume to have full ownership of the process (other services could be running in separate threads). Additionally all examples have generally been updated so that `main()` returns a `Result` from `run()` Fixes: rust-windowing#2709
rib · Jun 22, 2023 · 7293fe0 · 7293fe0
1 parent b5d799e
commit 7293fe0
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Showing 37 changed files with 92 additions and 112 deletions.
diff --git a/examples/child_window.rs b/examples/child_window.rs
@@ -3,7 +3,7 @@
 mod fill;
 
 #[cfg(any(x11_platform, macos_platform, windows_platform))]
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     use std::collections::HashMap;
 
     use raw_window_handle::HasRawWindowHandle;

diff --git a/examples/control_flow.rs b/examples/control_flow.rs
@@ -27,7 +27,7 @@ enum Mode {
 const WAIT_TIME: time::Duration = time::Duration::from_millis(100);
 const POLL_SLEEP_TIME: time::Duration = time::Duration::from_millis(100);
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
 
     println!("Press '1' to switch to Wait mode.");
@@ -122,5 +122,5 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
diff --git a/examples/cursor.rs b/examples/cursor.rs
@@ -10,7 +10,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -54,7 +54,7 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
 
 const CURSORS: &[CursorIcon] = &[

diff --git a/examples/cursor_grab.rs b/examples/cursor_grab.rs
@@ -11,7 +11,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -73,5 +73,5 @@ fn main() {
             Event::RedrawRequested(_) => fill::fill_window(&window),
             _ => (),
         }
-    });
+    })
 }
diff --git a/examples/custom_events.rs b/examples/custom_events.rs
@@ -1,7 +1,7 @@
 #![allow(clippy::single_match)]
 
 #[cfg(not(wasm_platform))]
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     use simple_logger::SimpleLogger;
     use winit::{
         event::{Event, WindowEvent},
@@ -52,7 +52,7 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
 
 #[cfg(wasm_platform)]

diff --git a/examples/drag_window.rs b/examples/drag_window.rs
@@ -11,7 +11,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -69,7 +69,7 @@ fn main() {
             }
         }
         _ => (),
-    });
+    })
 }
 
 fn name_windows(window_id: WindowId, switched: bool, window_1: &Window, window_2: &Window) {

diff --git a/examples/fullscreen.rs b/examples/fullscreen.rs
@@ -12,7 +12,7 @@ use winit::platform::macos::WindowExtMacOS;
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -131,5 +131,5 @@ fn main() {
             }
             _ => {}
         }
-    });
+    })
 }
diff --git a/examples/handling_close.rs b/examples/handling_close.rs
@@ -11,7 +11,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -87,5 +87,5 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
diff --git a/examples/ime.rs b/examples/ime.rs
@@ -13,7 +13,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new()
         .with_level(LevelFilter::Trace)
         .init()
@@ -105,5 +105,5 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
diff --git a/examples/key_binding.rs b/examples/key_binding.rs
@@ -17,7 +17,7 @@ fn main() {
 }
 
 #[cfg(any(target_os = "macos", target_os = "windows", target_os = "linux"))]
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     #[path = "util/fill.rs"]
     mod fill;
 
@@ -61,5 +61,5 @@ fn main() {
             }
             _ => (),
         };
-    });
+    })
 }
diff --git a/examples/mouse_wheel.rs b/examples/mouse_wheel.rs
@@ -10,7 +10,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -64,5 +64,5 @@ In other words, the deltas indicate the direction in which to move the content (
             }
             _ => (),
         }
-    });
+    })
 }
diff --git a/examples/multithreaded.rs b/examples/multithreaded.rs
@@ -1,7 +1,7 @@
 #![allow(clippy::single_match)]
 
 #[cfg(not(wasm_platform))]
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     use std::{collections::HashMap, sync::mpsc, thread, time::Duration};
 
     use simple_logger::SimpleLogger;

diff --git a/examples/multiwindow.rs b/examples/multiwindow.rs
@@ -13,7 +13,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 

diff --git a/examples/request_redraw.rs b/examples/request_redraw.rs
@@ -10,7 +10,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -41,5 +41,5 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
diff --git a/examples/request_redraw_threaded.rs b/examples/request_redraw_threaded.rs
@@ -1,7 +1,7 @@
 #![allow(clippy::single_match)]
 
 #[cfg(not(wasm_platform))]
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     use std::{sync::Arc, thread, time};
 
     use simple_logger::SimpleLogger;
@@ -49,7 +49,7 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
 
 #[cfg(wasm_platform)]

diff --git a/examples/resizable.rs b/examples/resizable.rs
@@ -12,7 +12,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -53,5 +53,5 @@ fn main() {
             }
             _ => (),
         };
-    });
+    })
 }
diff --git a/examples/theme.rs b/examples/theme.rs
@@ -11,7 +11,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -75,5 +75,5 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
diff --git a/examples/timer.rs b/examples/timer.rs
@@ -16,7 +16,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -47,5 +47,5 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
diff --git a/examples/touchpad_gestures.rs b/examples/touchpad_gestures.rs
@@ -8,7 +8,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -47,5 +47,5 @@ fn main() {
         } else if let Event::RedrawRequested(_) = event {
             fill::fill_window(&window);
         }
-    });
+    })
 }
diff --git a/examples/transparent.rs b/examples/transparent.rs
@@ -10,7 +10,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -36,5 +36,5 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
diff --git a/examples/web.rs b/examples/web.rs
@@ -7,7 +7,7 @@ use winit::{
     window::{Fullscreen, WindowBuilder},
 };
 
-pub fn main() {
+pub fn main() -> std::result::Result<(), impl std::error::Error> {
     let event_loop = EventLoop::new();
 
     let window = WindowBuilder::new()
@@ -53,7 +53,7 @@ pub fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
 
 #[cfg(wasm_platform)]
@@ -66,7 +66,7 @@ mod wasm {
         console_log::init_with_level(log::Level::Debug).expect("error initializing logger");
 
         #[allow(clippy::main_recursion)]
-        super::main();
+        let _ = super::main();
     }
 
     pub fn insert_canvas_and_create_log_list(window: &Window) -> web_sys::Element {

diff --git a/examples/web_aspect_ratio.rs b/examples/web_aspect_ratio.rs
@@ -45,7 +45,7 @@ This example demonstrates the desired future functionality which will possibly b
         // Render once with the size info we currently have
         render_circle(&canvas, window.inner_size());
 
-        event_loop.run(move |event, _, control_flow| {
+        let _ = event_loop.run(move |event, _, control_flow| {
             *control_flow = ControlFlow::Wait;
 
             match event {

diff --git a/examples/window.rs b/examples/window.rs
@@ -10,7 +10,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -28,7 +28,10 @@ fn main() {
             Event::WindowEvent {
                 event: WindowEvent::CloseRequested,
                 window_id,
-            } if window_id == window.id() => control_flow.set_exit(),
+            } if window_id == window.id() => {
+                log::warn!("Close button pressed");
+                control_flow.set_exit()
+            }
             Event::MainEventsCleared => {
                 window.request_redraw();
             }
@@ -37,5 +40,5 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }
diff --git a/examples/window_buttons.rs b/examples/window_buttons.rs
@@ -14,7 +14,7 @@ use winit::{
 #[path = "util/fill.rs"]
 mod fill;
 
-fn main() {
+fn main() -> std::result::Result<(), impl std::error::Error> {
     SimpleLogger::new().init().unwrap();
     let event_loop = EventLoop::new();
 
@@ -71,5 +71,5 @@ fn main() {
             }
             _ => (),
         }
-    });
+    })
 }