feat(glfw): add setting window close callback

1 files changed, 34 insertions, 0 deletions

diff --git a/glfw/src/window.rs b/glfw/src/window.rs
index 079b2fb..40eb300 100644
--- a/glfw/src/window.rs
+++ b/glfw/src/window.rs
@@ -117,6 +117,20 @@ impl Window
         })
     }
 
+    /// Sets the callback which is called when the user attempts to close the window.
+    pub fn set_close_callback(&self, callback: impl Fn() + 'static)
+    {
+        CLOSE_CALLBACK.with_borrow_mut(|cb| {
+            *cb = Some(Box::new(callback));
+        });
+
+        // SAFETY: The initialize function (called when the window is created) makes sure
+        // the current thread is the main thread
+        unsafe {
+            crate::ffi::glfwSetWindowCloseCallback(self.handle, Some(close_callback));
+        }
+    }
+
     pub fn set_framebuffer_size_callback(&self, callback: impl Fn(Size) + 'static)
     {
         FRAMEBUFFER_SIZE_CB.with_borrow_mut(|framebuffer_size_cb| {
@@ -661,18 +675,38 @@ pub struct CursorPosition
     pub y: f64,
 }
 
+type CloseCallback = Box<dyn Fn()>;
 type FramebufferSizeCb = Box<dyn Fn(Size)>;
 type KeyCallback = Box<dyn Fn(Key, i32, KeyState, KeyModifiers)>;
 type CursorPositionCallback = Box<dyn Fn(CursorPosition)>;
 type MouseButtonCallback = Box<dyn Fn(MouseButton, MouseButtonState, KeyModifiers)>;
 
 thread_local! {
+static CLOSE_CALLBACK: RefCell<Option<CloseCallback>> = RefCell::new(None);
 static FRAMEBUFFER_SIZE_CB: RefCell<Option<FramebufferSizeCb>> = RefCell::new(None);
 static KEY_CALLBACK: RefCell<Option<KeyCallback>> = RefCell::new(None);
 static CURSOR_POS_CALLBACK: RefCell<Option<CursorPositionCallback>> = RefCell::new(None);
 static MOUSE_BUTTON_CALLBACK: RefCell<Option<MouseButtonCallback>> = RefCell::new(None);
 }
 
+extern "C" fn close_callback(_window: *mut crate::ffi::GLFWwindow)
+{
+    // Unwinds are catched because unwinding from Rust code into foreign code is UB.
+    let res = catch_unwind(|| {
+        CLOSE_CALLBACK
+            .try_with(|close_cb| {
+                if let Some(cb) = close_cb.borrow().as_deref() {
+                    cb();
+                }
+            })
+            .ok();
+    });
+
+    if res.is_err() {
+        println!("ERROR: Panic in window close callback");
+    }
+}
+
 extern "C" fn framebuffer_size_callback(
     _window: *mut crate::ffi::GLFWwindow,
     c_width: c_int,