[PATCH weston 2/3] compositor: add a way to change the keyboard leds

[Giulio Camuffo]

This adds a function weston_keyboard_set_leds() which can be used
to change the state of the num lock and the caps lock leds.
Only the evdev and libinput backends supports this, since it doesn't
make sense for embedded sessions.
---
 src/compositor.h |  3 +++
 src/input.c      | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/src/compositor.h b/src/compositor.h
index c0fc0a6..30a0964 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -393,6 +393,9 @@ weston_keyboard_start_grab(struct weston_keyboard *device,
 			   struct weston_keyboard_grab *grab);
 void
 weston_keyboard_end_grab(struct weston_keyboard *keyboard);
+int
+weston_keyboard_set_leds(struct weston_keyboard *keyboard,
+			 enum weston_led maks, enum weston_led value);
 
 struct weston_touch *
 weston_touch_create(void);
diff --git a/src/input.c b/src/input.c
index 975cd77..1b0c6e5 100644
--- a/src/input.c
+++ b/src/input.c
@@ -1062,6 +1062,56 @@ notify_axis(struct weston_seat *seat, uint32_t time, uint32_t axis,
 				     value);
 }
 
+WL_EXPORT int
+weston_keyboard_set_leds(struct weston_keyboard *keyboard,
+			 enum weston_led mask, enum weston_led value)
+{
+	uint32_t mods_depressed, mods_latched, mods_locked, group;
+	uint32_t serial;
+	int num, caps;
+
+	/* We don't want the leds to go out of sync with the actual state
+	 * so if the backend has no way to change the leds don't try to
+	 * change the state */
+	if (!keyboard->seat->led_update)
+		return -1;
+
+	mods_depressed = xkb_state_serialize_mods(keyboard->xkb_state.state,
+						XKB_STATE_DEPRESSED);
+	mods_latched = xkb_state_serialize_mods(keyboard->xkb_state.state,
+						XKB_STATE_LATCHED);
+	mods_locked = xkb_state_serialize_mods(keyboard->xkb_state.state,
+						XKB_STATE_LOCKED);
+	group = xkb_state_serialize_group(keyboard->xkb_state.state,
+                                      XKB_STATE_EFFECTIVE);
+
+	num = (1 << keyboard->xkb_info->mod2_mod);
+	caps = (1 << keyboard->xkb_info->caps_mod);
+	if (mask & LED_NUM_LOCK) {
+		if (value & LED_NUM_LOCK)
+			mods_locked |= num;
+		else
+			mods_locked = mods_locked & ~num;
+	}
+	if (mask & LED_CAPS_LOCK) {
+		if (value & LED_CAPS_LOCK)
+			mods_locked |= caps;
+		else
+			mods_locked = mods_locked & ~caps;
+	}
+	if (mask & LED_SCROLL_LOCK)
+		weston_log("Changing the LED_SCROLL_LOCK value is not supported.");
+
+	xkb_state_update_mask(keyboard->xkb_state.state, mods_depressed,
+			      mods_latched, mods_locked, 0, 0, group);
+
+	serial = wl_display_next_serial(
+				keyboard->seat->compositor->wl_display);
+	notify_modifiers(keyboard->seat, serial);
+
+	return 0;
+}
+
 #ifdef ENABLE_XKBCOMMON
 WL_EXPORT void
 notify_modifiers(struct weston_seat *seat, uint32_t serial)
-- 
2.0.4