Update glium integration to allow mutable borrowing

examples/drm.rs

@@ -174,7 +174,7 @@ impl DrmHandler<Card> for DrmHandlerImpl {
         frame.clear_color(0.8, 0.8, 0.9, 1.0);
         // redraw the frame, in a simple but inneficient way
         {
-            let screen_dimensions = self.drawer.get_framebuffer_dimensions();
+            let screen_dimensions = self.drawer.borrow().get_framebuffer_dimensions();
             self.window_map
                 .borrow()
                 .with_windows_from_bottom_to_top(|toplevel_surface, initial_place| {

examples/helpers/glium.rs

@@ -6,7 +6,7 @@ use smithay::backend::graphics::egl::EGLGraphicsBackend;
 use smithay::backend::graphics::egl::error::Result as EGLResult;
 use smithay::backend::graphics::egl::wayland::{EGLDisplay, EGLImages, EGLWaylandExtensions, Format};
 use smithay::backend::graphics::glium::GliumGraphicsBackend;
-use std::borrow::Borrow;
+use std::cell::Ref;
 use std::ops::Deref;
 use wayland_server::Display;
 
@@ -25,16 +25,8 @@ pub struct GliumDrawer<F: EGLGraphicsBackend + 'static> {
     program: glium::Program,
 }
 
-impl<F: EGLGraphicsBackend + 'static> Deref for GliumDrawer<F> {
+impl<F: EGLGraphicsBackend + 'static> GliumDrawer<F> {
-    type Target = F;
+    pub fn borrow(&self) -> Ref<F> {
-
-    fn deref(&self) -> &F {
-        self.borrow()
-    }
-}
-
-impl<F: EGLGraphicsBackend + 'static> Borrow<F> for GliumDrawer<F> {
-    fn borrow(&self) -> &F {
         self.display.borrow()
     }
 }

examples/udev.rs

@@ -439,6 +439,7 @@ impl UdevHandlerImpl {
 
                         // create cursor
                         renderer
+                            .borrow()
                             .set_cursor_representation(&self.pointer_image, (2, 2))
                             .unwrap();
 
@@ -518,13 +519,15 @@ impl DrmHandler<SessionFdDrmDevice> for DrmHandlerImpl {
         if let Some(drawer) = self.backends.borrow().get(&crtc) {
             {
                 let (x, y) = *self.pointer_location.borrow();
-                let _ = drawer.set_cursor_position(x.trunc().abs() as u32, y.trunc().abs() as u32);
+                let _ = drawer
+                    .borrow()
+                    .set_cursor_position(x.trunc().abs() as u32, y.trunc().abs() as u32);
             }
             let mut frame = drawer.draw();
             frame.clear_color(0.8, 0.8, 0.9, 1.0);
             // redraw the frame, in a simple but inneficient way
             {
-                let screen_dimensions = drawer.get_framebuffer_dimensions();
+                let screen_dimensions = drawer.borrow().get_framebuffer_dimensions();
                 self.window_map.borrow().with_windows_from_bottom_to_top(
                     |toplevel_surface, initial_place| {
                         if let Some(wl_surface) = toplevel_surface.get_surface() {

examples/winit.rs

@@ -241,7 +241,7 @@ fn main() {
         frame.clear(None, Some((0.8, 0.8, 0.9, 1.0)), false, Some(1.0), None);
         // redraw the frame, in a simple but inneficient way
         {
-            let screen_dimensions = drawer.get_framebuffer_dimensions();
+            let screen_dimensions = drawer.borrow().get_framebuffer_dimensions();
             window_map
                 .borrow()
                 .with_windows_from_bottom_to_top(|toplevel_surface, initial_place| {

src/backend/graphics/glium.rs

@@ -7,7 +7,7 @@ use glium::Frame;
 use glium::SwapBuffersError as GliumSwapBuffersError;
 use glium::backend::{Backend, Context, Facade};
 use glium::debug::DebugCallbackBehavior;
-use std::borrow::Borrow;
+use std::cell::{Ref, RefCell, RefMut};
 use std::os::raw::c_void;
 use std::rc::Rc;
 use wayland_server::Display;
@@ -28,11 +28,11 @@ pub struct GliumGraphicsBackend<T: EGLGraphicsBackend> {
     backend: Rc<InternalBackend<T>>,
 }
 
-struct InternalBackend<T: EGLGraphicsBackend>(T);
+struct InternalBackend<T: EGLGraphicsBackend>(RefCell<T>);
 
 impl<T: EGLGraphicsBackend + 'static> GliumGraphicsBackend<T> {
     fn new(backend: T) -> GliumGraphicsBackend<T> {
-        let internal = Rc::new(InternalBackend(backend));
+        let internal = Rc::new(InternalBackend(RefCell::new(backend)));
 
         GliumGraphicsBackend {
             // cannot fail
@@ -56,11 +56,24 @@ impl<T: EGLGraphicsBackend + 'static> GliumGraphicsBackend<T> {
             self.backend.get_framebuffer_dimensions(),
         )
     }
+
+    /// Borrow the underlying backend.
+    ///
+    /// This follows the same semantics as `std::cell:RefCell`.
+    /// Multiple read-only borrows are possible. Borrowing the
+    /// backend while there is a mutable reference will panic.
+    pub fn borrow(&self) -> Ref<T> {
+        self.backend.0.borrow()
     }
 
-impl<T: EGLGraphicsBackend> Borrow<T> for GliumGraphicsBackend<T> {
+    /// Borrow the underlying backend mutably.
-    fn borrow(&self) -> &T {
+    ///
-        &self.backend.0
+    /// This follows the same semantics as `std::cell:RefCell`.
+    /// Holding any other borrow while trying to borrow the backend
+    /// mutably will panic. Note that glium will borrow the backend
+    /// (not mutably) during rendering.
+    pub fn borrow_mut(&mut self) -> RefMut<T> {
+        self.backend.0.borrow_mut()
     }
 }
 
@@ -80,28 +93,28 @@ impl<T: EGLGraphicsBackend + EGLWaylandExtensions + 'static> EGLWaylandExtension
     for GliumGraphicsBackend<T>
 {
     fn bind_wl_display(&self, display: &Display) -> EGLResult<EGLDisplay> {
-        (*self.backend).0.bind_wl_display(display)
+        (*self.backend).0.borrow().bind_wl_display(display)
     }
 }
 
 unsafe impl<T: EGLGraphicsBackend> Backend for InternalBackend<T> {
     fn swap_buffers(&self) -> Result<(), GliumSwapBuffersError> {
-        self.0.swap_buffers().map_err(Into::into)
+        self.0.borrow().swap_buffers().map_err(Into::into)
     }
 
     unsafe fn get_proc_address(&self, symbol: &str) -> *const c_void {
-        self.0.get_proc_address(symbol) as *const c_void
+        self.0.borrow().get_proc_address(symbol) as *const c_void
     }
 
     fn get_framebuffer_dimensions(&self) -> (u32, u32) {
-        self.0.get_framebuffer_dimensions()
+        self.0.borrow().get_framebuffer_dimensions()
     }
 
     fn is_current(&self) -> bool {
-        self.0.is_current()
+        self.0.borrow().is_current()
     }
 
     unsafe fn make_current(&self) {
-        self.0.make_current().expect("Context was lost")
+        self.0.borrow().make_current().expect("Context was lost")
     }
 }