[mutter] clutter/evdev: implement toggle keys support

[Olivier Fourdan <ofourdan src gnome org>]

commit 356b4b0dc5129210472e6b349213d39dd609517c
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Thu Oct 19 13:03:22 2017 +0200

    clutter/evdev: implement toggle keys support
    
    Keeping Shift pressed for 8 seconds enables slow keys, pressing Shift 5
    times in a row enables sticky keys.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=788564

 clutter/clutter/evdev/clutter-input-device-evdev.c |  130 ++++++++++++++++++++
 clutter/clutter/evdev/clutter-input-device-evdev.h |    3 +
 2 files changed, 133 insertions(+), 0 deletions(-)
---
diff --git a/clutter/clutter/evdev/clutter-input-device-evdev.c 
b/clutter/clutter/evdev/clutter-input-device-evdev.c
index 80562b9..9d653c2 100644
--- a/clutter/clutter/evdev/clutter-input-device-evdev.c
+++ b/clutter/clutter/evdev/clutter-input-device-evdev.c
@@ -65,6 +65,7 @@ typedef struct _SlowKeysEventPending
 
 static void clear_slow_keys      (ClutterInputDeviceEvdev *device);
 static void stop_bounce_keys     (ClutterInputDeviceEvdev *device);
+static void stop_toggle_slowkeys (ClutterInputDeviceEvdev *device);
 
 static void
 clutter_input_device_evdev_finalize (GObject *object)
@@ -81,6 +82,7 @@ clutter_input_device_evdev_finalize (GObject *object)
 
   clear_slow_keys (device_evdev);
   stop_bounce_keys (device_evdev);
+  stop_toggle_slowkeys (device_evdev);
 
   G_OBJECT_CLASS (clutter_input_device_evdev_parent_class)->finalize (object);
 }
@@ -519,6 +521,13 @@ set_stickykeys_off (ClutterInputDeviceEvdev *device)
 }
 
 static void
+set_stickykeys_on (ClutterInputDeviceEvdev *device)
+{
+  device->a11y_flags |= CLUTTER_A11Y_STICKY_KEYS_ENABLED;
+  notify_stickykeys_change (device);
+}
+
+static void
 clear_stickykeys_event (ClutterEvent            *event,
                         ClutterInputDeviceEvdev *device)
 {
@@ -527,6 +536,28 @@ clear_stickykeys_event (ClutterEvent            *event,
 }
 
 static void
+set_slowkeys_off (ClutterInputDeviceEvdev *device)
+{
+  device->a11y_flags &= ~CLUTTER_A11Y_SLOW_KEYS_ENABLED;
+
+  g_signal_emit_by_name (CLUTTER_INPUT_DEVICE (device)->device_manager,
+                         "kbd-a11y-flags-changed",
+                         device->a11y_flags,
+                         CLUTTER_A11Y_SLOW_KEYS_ENABLED);
+}
+
+static void
+set_slowkeys_on (ClutterInputDeviceEvdev *device)
+{
+  device->a11y_flags |= CLUTTER_A11Y_SLOW_KEYS_ENABLED;
+
+  g_signal_emit_by_name (CLUTTER_INPUT_DEVICE (device)->device_manager,
+                         "kbd-a11y-flags-changed",
+                         device->a11y_flags,
+                         CLUTTER_A11Y_SLOW_KEYS_ENABLED);
+}
+
+static void
 handle_stickykeys_press (ClutterEvent            *event,
                          ClutterInputDeviceEvdev *device)
 {
@@ -591,6 +622,90 @@ handle_stickykeys_release (ClutterEvent            *event,
   update_stickykeys_event (event, device, 0, device->stickykeys_locked_mask);
 }
 
+static gboolean
+trigger_toggle_slowkeys (gpointer data)
+{
+  ClutterInputDeviceEvdev *device = data;
+
+  device->toggle_slowkeys_timer = 0;
+
+  if (device->a11y_flags & CLUTTER_A11Y_FEATURE_STATE_CHANGE_BEEP)
+    clutter_input_device_evdev_bell_notify ();
+
+  if (device->a11y_flags & CLUTTER_A11Y_SLOW_KEYS_ENABLED)
+    set_slowkeys_off (device);
+  else
+    set_slowkeys_on (device);
+
+  return G_SOURCE_REMOVE;
+}
+
+static void
+start_toggle_slowkeys (ClutterInputDeviceEvdev *device)
+{
+  if (device->toggle_slowkeys_timer != 0)
+    return;
+
+  device->toggle_slowkeys_timer =
+    clutter_threads_add_timeout (8 * 1000 /* 8 secs */,
+                                 trigger_toggle_slowkeys,
+                                 device);
+}
+
+static void
+stop_toggle_slowkeys (ClutterInputDeviceEvdev *device)
+{
+  if (device->toggle_slowkeys_timer)
+    {
+      g_source_remove (device->toggle_slowkeys_timer);
+      device->toggle_slowkeys_timer = 0;
+    }
+}
+
+static void
+handle_togglekeys_press (ClutterEvent            *event,
+                         ClutterInputDeviceEvdev *device)
+{
+  if (event->key.keyval == XKB_KEY_Shift_L || event->key.keyval == XKB_KEY_Shift_R)
+    {
+      start_toggle_slowkeys (device);
+
+      if (event->key.time > device->last_shift_time + 15 * 1000 /* 15 secs  */)
+        device->shift_count = 1;
+      else
+        device->shift_count++;
+
+      device->last_shift_time = event->key.time;
+    }
+  else
+    {
+      device->shift_count = 0;
+      stop_toggle_slowkeys (device);
+    }
+}
+
+static void
+handle_togglekeys_release (ClutterEvent            *event,
+                           ClutterInputDeviceEvdev *device)
+{
+  if (event->key.keyval == XKB_KEY_Shift_L || event->key.keyval == XKB_KEY_Shift_R)
+    {
+      stop_toggle_slowkeys (device);
+      if (device->shift_count >= 5)
+        {
+          device->shift_count = 0;
+
+          if (device->a11y_flags & CLUTTER_A11Y_FEATURE_STATE_CHANGE_BEEP)
+            clutter_input_device_evdev_bell_notify ();
+
+          if (device->a11y_flags & CLUTTER_A11Y_STICKY_KEYS_ENABLED)
+            set_stickykeys_off (device);
+          else
+            set_stickykeys_on (device);
+        }
+    }
+}
+
 static void
 clutter_input_device_evdev_process_kbd_a11y_event (ClutterEvent               *event,
                                                    ClutterInputDevice         *device,
@@ -601,6 +716,14 @@ clutter_input_device_evdev_process_kbd_a11y_event (ClutterEvent               *e
   if (!device_evdev->a11y_flags & CLUTTER_A11Y_KEYBOARD_ENABLED)
     goto emit_event;
 
+  if (device_evdev->a11y_flags & CLUTTER_A11Y_TOGGLE_KEYS_ENABLED)
+    {
+      if (event->type == CLUTTER_KEY_PRESS)
+        handle_togglekeys_press (event, device_evdev);
+      else
+        handle_togglekeys_release (event, device_evdev);
+    }
+
   if ((device_evdev->a11y_flags & CLUTTER_A11Y_BOUNCE_KEYS_ENABLED) &&
       (get_debounce_delay (device) != 0))
     {
@@ -655,6 +778,13 @@ clutter_input_device_evdev_apply_kbd_a11y_settings (ClutterInputDeviceEvdev *dev
       update_internal_xkb_state (device, 0, 0);
     }
 
+  if (changed_flags & (CLUTTER_A11Y_KEYBOARD_ENABLED | CLUTTER_A11Y_TOGGLE_KEYS_ENABLED))
+    {
+      device->toggle_slowkeys_timer = 0;
+      device->shift_count = 0;
+      device->last_shift_time = 0;
+    }
+
   /* Keep our own copy of keyboard a11y features flags to see what changes */
   device->a11y_flags = settings->controls;
 }
diff --git a/clutter/clutter/evdev/clutter-input-device-evdev.h 
b/clutter/clutter/evdev/clutter-input-device-evdev.h
index f80b4aa..b8e1f99 100644
--- a/clutter/clutter/evdev/clutter-input-device-evdev.h
+++ b/clutter/clutter/evdev/clutter-input-device-evdev.h
@@ -79,6 +79,9 @@ struct _ClutterInputDeviceEvdev
   xkb_mod_mask_t stickykeys_depressed_mask;
   xkb_mod_mask_t stickykeys_latched_mask;
   xkb_mod_mask_t stickykeys_locked_mask;
+  guint toggle_slowkeys_timer;
+  guint16 shift_count;
+  guint32 last_shift_time;
 };
 
 GType                     _clutter_input_device_evdev_get_type        (void) G_GNUC_CONST;