getModiferState: always return 0 on X11

The clutter reported modifier state is easily stuck on X11:
- Enter "clutter mode". Press and hold ctrl whild exiting (usually ctrl-ecs)
- Clutter will now report ctrl after ctrl is released causing windows to go
  directly to dnd mode when moved.

notes.org

@@ -294,3 +294,5 @@ To turn on off without disrupting flow too much use ~GLib.setenv("CLUTTER_SHOW_F
 ** Focus and active workspace
 It's not possible the have a focused window which doesn't belong to the active workspace
 ~global.display.focus_window.workspace === workspaceManger.get_active_workspace()~
+* Clutter animation
+  ~time: 0~ does not result in an instant animation. A default duration seems to be selected instead.

tiling.js

@@ -2706,16 +2706,7 @@ function grabBegin(metaWindow, type) {
         case Meta.GrabOp.MOVING:
             inGrab = new Extension.imports.grab.MoveGrab(metaWindow, type);
 
-            let d;
-            if (Clutter.DeviceManager) {
-                let dm = Clutter.DeviceManager.get_default();
-                d = dm.get_core_device(Clutter.InputDeviceType.KEYBOARD_DEVICE);
-            } else {
-                let backend = Clutter.get_default_backend()
-                let seat = backend.get_default_seat()
-                d = seat.get_keyboard()
-            }
-            if (d.get_modifier_state() & Clutter.ModifierType.CONTROL_MASK) {
+            if (utils.getModiferState() & Clutter.ModifierType.CONTROL_MASK) {
                 inGrab.begin();
                 inGrab.beginDnD();
             } else if (inGrab.initialSpace && inGrab.initialSpace.indexOf(metaWindow) > -1) {

utils.js

@@ -80,6 +80,16 @@ function ppEnumValue(value, genum) {
     }
 }
 
+function ppModiferState(state) {
+    let mods = [];
+    for (let [mod, mask] of Object.entries(imports.gi.Clutter.ModifierType)) {
+        if (mask & state) {
+            mods.push(mod);
+        }
+    }
+    return mods.join(", ")
+}
+
 /**
  * Look up the function by name at call time. This makes it convenient to
  * redefine the function without re-registering all signal handler, keybindings,
@@ -264,6 +274,29 @@ function warpPointer(x, y) {
     }
 }
 
+/**
+ * Return current modifiers state (or'ed Clutter.ModifierType.*)
+ * NB: Only on wayland. (Returns 0 on X11)
+ *
+ * Note: It's possible to get the modifier state through Gdk on X11, but move
+ * grabs is not triggered when ctrl is held down, making it useless for our purpose atm.
+ */
+function getModiferState() {
+    if (!Meta.is_wayland_compositor())
+        return 0;
+
+    let keyboard;
+    if (Clutter.DeviceManager) {
+        let dm = Clutter.DeviceManager.get_default();
+        keyboard = dm.get_core_device(Clutter.InputDeviceType.KEYBOARD_DEVICE);
+    } else {
+        let backend = Clutter.get_default_backend();
+        let seat = backend.get_default_seat();
+        keyboard = seat.get_keyboard();
+    }
+    return keyboard.get_modifier_state();
+}
+
 function monitorOfPoint(x, y) {
     // get_monitor_index_for_rect "helpfully" returns the primary monitor index for out of bounds rects..
     const Main = imports.ui.main;