input: Add core API to update the keymap

How and when to update the keymap is left to each backend.

The new keymap only becomes effective when no keys are pressed and we
keep latched and locked modifiers from the previous state.

src/compositor.h

@@ -485,6 +485,7 @@ struct weston_seat {
 		struct xkb_state *state;
 		enum weston_led leds;
 	} xkb_state;
+	struct xkb_keymap *pending_keymap;
 
 	struct input_method *input_method;
 	char *seat_name;
@@ -1179,6 +1180,8 @@ void
 weston_seat_release_touch(struct weston_seat *seat);
 void
 weston_seat_repick(struct weston_seat *seat);
+void
+weston_seat_update_keymap(struct weston_seat *seat, struct xkb_keymap *keymap);
 
 void
 weston_seat_release(struct weston_seat *seat);

src/input.c

@@ -901,6 +901,86 @@ update_modifier_state(struct weston_seat *seat, uint32_t serial, uint32_t key,
 
 	notify_modifiers(seat, serial);
 }
+
+static void
+send_keymap(struct wl_resource *resource, struct weston_xkb_info *xkb_info)
+{
+	wl_keyboard_send_keymap(resource,
+				WL_KEYBOARD_KEYMAP_FORMAT_XKB_V1,
+				xkb_info->keymap_fd,
+				xkb_info->keymap_size);
+}
+
+static void
+send_modifiers(struct wl_resource *resource, uint32_t serial, struct weston_keyboard *keyboard)
+{
+	wl_keyboard_send_modifiers(resource, serial,
+				   keyboard->modifiers.mods_depressed,
+				   keyboard->modifiers.mods_latched,
+				   keyboard->modifiers.mods_locked,
+				   keyboard->modifiers.group);
+}
+
+static struct weston_xkb_info *
+weston_xkb_info_create(struct xkb_keymap *keymap);
+static void
+weston_xkb_info_destroy(struct weston_xkb_info *xkb_info);
+
+static void
+update_keymap(struct weston_seat *seat)
+{
+	struct wl_resource *resource;
+	struct weston_xkb_info *xkb_info;
+	struct xkb_state *state;
+	xkb_mod_mask_t latched_mods;
+	xkb_mod_mask_t locked_mods;
+
+	xkb_info = weston_xkb_info_create(seat->pending_keymap);
+
+	xkb_keymap_unref(seat->pending_keymap);
+	seat->pending_keymap = NULL;
+
+	if (!xkb_info) {
+		weston_log("failed to create XKB info\n");
+		return;
+	}
+
+	state = xkb_state_new(xkb_info->keymap);
+	if (!state) {
+		weston_log("failed to initialise XKB state\n");
+		weston_xkb_info_destroy(xkb_info);
+		return;
+	}
+
+	latched_mods = xkb_state_serialize_mods(seat->xkb_state.state, XKB_STATE_MODS_LATCHED);
+	locked_mods = xkb_state_serialize_mods(seat->xkb_state.state, XKB_STATE_MODS_LOCKED);
+	xkb_state_update_mask(state,
+			      0, /* depressed */
+			      latched_mods,
+			      locked_mods,
+			      0, 0, 0);
+
+	weston_xkb_info_destroy(seat->xkb_info);
+	seat->xkb_info = xkb_info;
+
+	xkb_state_unref(seat->xkb_state.state);
+	seat->xkb_state.state = state;
+
+	wl_resource_for_each(resource, &seat->keyboard->resource_list)
+		send_keymap(resource, xkb_info);
+	wl_resource_for_each(resource, &seat->keyboard->focus_resource_list)
+		send_keymap(resource, xkb_info);
+
+	notify_modifiers(seat, wl_display_next_serial(seat->compositor->wl_display));
+
+	if (!latched_mods && !locked_mods)
+		return;
+
+	wl_resource_for_each(resource, &seat->keyboard->resource_list)
+		send_modifiers(resource, wl_display_get_serial(seat->compositor->wl_display), seat->keyboard);
+	wl_resource_for_each(resource, &seat->keyboard->focus_resource_list)
+		send_modifiers(resource, wl_display_get_serial(seat->compositor->wl_display), seat->keyboard);
+}
 #else
 WL_EXPORT void
 notify_modifiers(struct weston_seat *seat, uint32_t serial)
@@ -912,6 +992,11 @@ update_modifier_state(struct weston_seat *seat, uint32_t serial, uint32_t key,
 		      enum wl_keyboard_key_state state)
 {
 }
+
+static void
+update_keymap(struct weston_seat *seat)
+{
+}
 #endif
 
 WL_EXPORT void
@@ -961,6 +1046,10 @@ notify_key(struct weston_seat *seat, uint32_t time, uint32_t key,
 
 	grab->interface->key(grab, time, key, state);
 
+	if (seat->pending_keymap &&
+	    keyboard->keys.size == 0)
+		update_keymap(seat);
+
 	if (update_state == STATE_UPDATE_AUTOMATIC) {
 		update_modifier_state(seat,
 				      wl_display_get_serial(compositor->wl_display),
@@ -1636,6 +1725,24 @@ weston_compositor_xkb_destroy(struct weston_compositor *ec)
 }
 #endif
 
+WL_EXPORT void
+weston_seat_update_keymap(struct weston_seat *seat, struct xkb_keymap *keymap)
+{
+	if (!seat->keyboard || !keymap)
+		return;
+
+#ifdef ENABLE_XKBCOMMON
+	if (!seat->compositor->use_xkbcommon)
+		return;
+
+	xkb_keymap_unref(seat->pending_keymap);
+	seat->pending_keymap = xkb_keymap_ref(keymap);
+
+	if (seat->keyboard->keys.size == 0)
+		update_keymap(seat);
+#endif
+}
+
 WL_EXPORT int
 weston_seat_init_keyboard(struct weston_seat *seat, struct xkb_keymap *keymap)
 {
@@ -1808,6 +1915,8 @@ weston_seat_release(struct weston_seat *seat)
 			xkb_state_unref(seat->xkb_state.state);
 		if (seat->xkb_info)
 			weston_xkb_info_destroy(seat->xkb_info);
+		if (seat->pending_keymap)
+			xkb_keymap_unref (seat->pending_keymap);
 	}
 #endif