backend: Update cursor visibility based on device availability

On startup, the cursor is kept hidden if there's any touchscreen available.
If the device that was last interacted is removed, we check on available
pointing devices though, so we don't possibly hide the pointer if there are
further mice/touchpads/etc.

Devices being added don't update cursor visibility, we wait for the user
interacting with those instead.

https://bugzilla.gnome.org/show_bug.cgi?id=712775

1 files changed, 81 insertions, 0 deletions

diff --git a/src/backends/meta-backend.c b/src/backends/meta-backend.c
index 474184aa..f55a4a02 100644
--- a/src/backends/meta-backend.c
+++ b/src/backends/meta-backend.c
@@ -137,6 +137,55 @@ on_device_added (ClutterDeviceManager *device_manager,
   create_device_monitor (backend, device_id);
 }
 
+static inline gboolean
+device_is_slave_touchscreen (ClutterInputDevice *device)
+{
+  return (clutter_input_device_get_device_mode (device) != CLUTTER_INPUT_MODE_MASTER &&
+          clutter_input_device_get_device_type (device) == CLUTTER_TOUCHSCREEN_DEVICE);
+}
+
+static inline gboolean
+check_has_pointing_device (ClutterDeviceManager *manager)
+{
+  const GSList *devices;
+
+  devices = clutter_device_manager_peek_devices (manager);
+
+  for (; devices; devices = devices->next)
+    {
+      ClutterInputDevice *device = devices->data;
+
+      if (clutter_input_device_get_device_mode (device) == CLUTTER_INPUT_MODE_MASTER)
+        continue;
+      if (clutter_input_device_get_device_type (device) == CLUTTER_TOUCHSCREEN_DEVICE ||
+          clutter_input_device_get_device_type (device) == CLUTTER_KEYBOARD_DEVICE)
+        continue;
+
+      return TRUE;
+    }
+
+  return FALSE;
+}
+
+static inline gboolean
+check_has_slave_touchscreen (ClutterDeviceManager *manager)
+{
+  const GSList *devices;
+
+  devices = clutter_device_manager_peek_devices (manager);
+
+  for (; devices; devices = devices->next)
+    {
+      ClutterInputDevice *device = devices->data;
+
+      if (clutter_input_device_get_device_mode (device) != CLUTTER_INPUT_MODE_MASTER &&
+          clutter_input_device_get_device_type (device) == CLUTTER_TOUCHSCREEN_DEVICE)
+        return TRUE;
+    }
+
+  return FALSE;
+}
+
 static void
 on_device_removed (ClutterDeviceManager *device_manager,
                    ClutterInputDevice   *device,
@@ -146,6 +195,32 @@ on_device_removed (ClutterDeviceManager *device_manager,
   int device_id = clutter_input_device_get_device_id (device);
 
   destroy_device_monitor (backend, device_id);
+
+  /* If the device the user last interacted goes away, check again pointer
+   * visibility.
+   */
+  if (backend->current_device_id == device_id)
+    {
+      MetaCursorTracker *cursor_tracker = meta_cursor_tracker_get_for_screen (NULL);
+      gboolean has_touchscreen, has_pointing_device;
+      ClutterInputDeviceType device_type;
+
+      device_type = clutter_input_device_get_device_type (device);
+      has_touchscreen = check_has_slave_touchscreen (device_manager);
+
+      if (device_type == CLUTTER_TOUCHSCREEN_DEVICE && has_touchscreen)
+        {
+          /* There's more touchscreens left, keep the pointer hidden */
+          meta_cursor_tracker_set_pointer_visible (cursor_tracker, FALSE);
+        }
+      else if (device_type != CLUTTER_KEYBOARD_DEVICE)
+        {
+          has_pointing_device = check_has_pointing_device (device_manager);
+          meta_cursor_tracker_set_pointer_visible (cursor_tracker,
+                                                   has_pointing_device &&
+                                                   !has_touchscreen);
+        }
+    }
 }
 
 static MetaMonitorManager *
@@ -178,7 +253,9 @@ meta_backend_real_post_init (MetaBackend *backend)
                                                     NULL, (GDestroyNotify) g_object_unref);
 
   {
+    MetaCursorTracker *cursor_tracker;
     ClutterDeviceManager *manager;
+    gboolean has_touchscreen = FALSE;
     GSList *devices, *l;
 
     /* Create the core device monitor. */
@@ -196,8 +273,12 @@ meta_backend_real_post_init (MetaBackend *backend)
       {
         ClutterInputDevice *device = l->data;
         on_device_added (manager, device, backend);
+        has_touchscreen |= device_is_slave_touchscreen (device);
       }
 
+    cursor_tracker = meta_cursor_tracker_get_for_screen (NULL);
+    meta_cursor_tracker_set_pointer_visible (cursor_tracker, !has_touchscreen);
+
     g_slist_free (devices);
   }