track suppressed keys and...

...forward non suppressed keys on release
fixes #242

anvil/src/input_handler.rs

@@ -30,6 +30,7 @@ impl<Backend> AnvilState<Backend> {
         let log = &self.log;
         let time = Event::time(&evt);
         let mut action = KeyAction::None;
+        let suppressed_keys = &mut self.suppressed_keys;
         self.keyboard
             .input(keycode, state, serial, time, |modifiers, keysym| {
                 debug!(log, "keysym";
@@ -37,15 +38,33 @@ impl<Backend> AnvilState<Backend> {
                     "mods" => format!("{:?}", modifiers),
                     "keysym" => ::xkbcommon::xkb::keysym_get_name(keysym)
                 );
-                action = process_keyboard_shortcut(*modifiers, keysym);
+
-                // forward to client only if action == KeyAction::Forward
+                // If the key is pressed and triggered a action
-                // both for pressed and released, to avoid inconsistencies
+                // we will not forward the key to the client.
-                matches!(action, KeyAction::Forward)
+                // Additionally add the key to the suppressed keys
+                // so that we can decide on a release if the key
+                // should be forwarded to the client or not.
+                if let KeyState::Pressed = state {
+                    action = process_keyboard_shortcut(*modifiers, keysym);
+
+                    // forward to client only if action == KeyAction::Forward
+                    let forward = matches!(action, KeyAction::Forward);
+
+                    if !forward {
+                        suppressed_keys.push(keysym);
+                    }
+
+                    forward
+                } else {
+                    let suppressed = suppressed_keys.contains(&keysym);
+
+                    if suppressed {
+                        suppressed_keys.retain(|k| *k != keysym);
+                    }
+
+                    !suppressed
+                }
             });
-        if let KeyState::Released = state {
-            // only process special actions on key press, not release
-            return KeyAction::None;
-        }
         action
     }
 

anvil/src/state.rs

@@ -40,6 +40,7 @@ pub struct AnvilState<BackendData> {
     // input-related fields
     pub pointer: PointerHandle,
     pub keyboard: KeyboardHandle,
+    pub suppressed_keys: Vec<u32>,
     pub pointer_location: (f64, f64),
     pub cursor_status: Arc<Mutex<CursorImageStatus>>,
     pub seat_name: String,
@@ -165,6 +166,7 @@ impl<BackendData: Backend + 'static> AnvilState<BackendData> {
             socket_name,
             pointer,
             keyboard,
+            suppressed_keys: Vec::new(),
             cursor_status,
             pointer_location: (0.0, 0.0),
             seat_name,