rootston: add support for text input and the basic of input method

The compositor acts as a relay between applications using the text-input protocol and input methods using the input-method protocol.

This change implements the basic but useful support for input-method, leaving out grabs as well as popups.

include/rootston/desktop.h

@@ -9,13 +9,15 @@
 #include <wlr/types/wlr_idle_inhibit_v1.h>
 #include <wlr/types/wlr_idle.h>
 #include <wlr/types/wlr_input_inhibitor.h>
+#include <wlr/types/wlr_input_method_v2.h>
 #include <wlr/types/wlr_layer_shell_v1.h>
 #include <wlr/types/wlr_list.h>
 #include <wlr/types/wlr_output_layout.h>
 #include <wlr/types/wlr_output.h>
 #include <wlr/types/wlr_primary_selection.h>
 #include <wlr/types/wlr_screencopy_v1.h>
 #include <wlr/types/wlr_screenshooter.h>
+#include <wlr/types/wlr_text_input_v3.h>
 #include <wlr/types/wlr_virtual_keyboard_v1.h>
 #include <wlr/types/wlr_wl_shell.h>
 #include <wlr/types/wlr_xcursor_manager.h>
@@ -53,6 +55,8 @@ struct roots_desktop {
 	struct wlr_idle_inhibit_manager_v1 *idle_inhibit;
 	struct wlr_input_inhibit_manager *input_inhibit;
 	struct wlr_layer_shell_v1 *layer_shell;
+	struct wlr_input_method_manager_v2 *input_method;
+	struct wlr_text_input_manager_v3 *text_input;
 	struct wlr_virtual_keyboard_manager_v1 *virtual_keyboard;
 	struct wlr_screencopy_manager_v1 *screencopy;
 	struct wlr_tablet_manager_v2 *tablet_v2;

include/rootston/seat.h

@@ -5,6 +5,7 @@
 #include "rootston/input.h"
 #include "rootston/keyboard.h"
 #include "rootston/layers.h"
+#include "rootston/text_input.h"
 
 struct roots_seat {
 	struct roots_input *input;
@@ -19,6 +20,8 @@ struct roots_seat {
 	// If the focused layer is set, views cannot receive keyboard focus
 	struct wlr_layer_surface_v1 *focused_layer;
 
+	struct roots_input_method_relay im_relay;
+
 	// If non-null, only this client can receive input events
 	struct wl_client *exclusive_client;
 

include/rootston/text_input.h

@@ -0,0 +1,63 @@
+#ifndef ROOTSTON_TEXT_INPUT_H
+#define ROOTSTON_TEXT_INPUT_H
+
+#include <wlr/types/wlr_text_input_v3.h>
+#include <wlr/types/wlr_input_method_v2.h>
+#include <wlr/types/wlr_surface.h>
+#include "rootston/seat.h"
+
+/**
+ * The relay structure manages the relationship between text-input and
+ * input_method interfaces on a given seat. Multiple text-input interfaces may
+ * be bound to a relay, but at most one will be focused (reveiving events) at
+ * a time. At most one input-method interface may be bound to the seat. The
+ * relay manages life cycle of both sides. When both sides are present and
+ * focused, the relay passes messages between them.
+ *
+ * Text input focus is a subset of keyboard focus - if the text-input is
+ * in the focused state, wl_keyboard sent an enter as well. However, having
+ * wl_keyboard focused doesn't mean that text-input will be focused.
+ */
+struct roots_input_method_relay {
+	struct roots_seat *seat;
+
+	struct wl_list text_inputs; // roots_text_input::link
+	struct wlr_input_method_v2 *input_method; // doesn't have to be present
+
+	struct wl_listener text_input_new;
+	struct wl_listener text_input_enable;
+	struct wl_listener text_input_commit;
+	struct wl_listener text_input_disable;
+	struct wl_listener text_input_destroy;
+
+	struct wl_listener input_method_new;
+	struct wl_listener input_method_commit;
+	struct wl_listener input_method_destroy;
+};
+
+struct roots_text_input {
+	struct roots_input_method_relay *relay;
+
+	struct wlr_text_input_v3 *input;
+	// The surface getting seat's focus. Stored for when text-input cannot
+	// be sent an enter event immediately after getting focus, e.g. when
+	// there's no input method available. Cleared once text-input is entered.
+	struct wlr_surface *pending_focused_surface;
+
+	struct wl_list link;
+
+	struct wl_listener pending_focused_surface_destroy;
+};
+
+void roots_input_method_relay_init(struct roots_seat *seat,
+	struct roots_input_method_relay *relay);
+
+// Updates currently focused surface. Surface must belong to the same seat.
+void roots_input_method_relay_set_focus(struct roots_input_method_relay *relay,
+	struct wlr_surface *surface);
+
+struct roots_text_input *roots_text_input_create(
+	struct roots_input_method_relay *relay,
+	struct wlr_text_input_v3 *text_input);
+
+#endif

rootston/desktop.c

@@ -949,6 +949,11 @@ struct roots_desktop *desktop_create(struct roots_server *server,
 	wl_signal_add(&desktop->input_inhibit->events.deactivate,
 		&desktop->input_inhibit_deactivate);
 
+	desktop->input_method =
+		wlr_input_method_manager_v2_create(server->wl_display);
+
+	desktop->text_input = wlr_text_input_manager_v3_create(server->wl_display);
+
 	desktop->virtual_keyboard = wlr_virtual_keyboard_manager_v1_create(
 		server->wl_display);
 	wl_signal_add(&desktop->virtual_keyboard->events.new_virtual_keyboard,

rootston/meson.build

@@ -9,6 +9,7 @@ sources = [
 	'main.c',
 	'output.c',
 	'seat.c',
+	'text_input.c',
 	'virtual_keyboard.c',
 	'wl_shell.c',
 	'xdg_shell.c',

rootston/seat.c

@@ -16,6 +16,7 @@
 #include "rootston/input.h"
 #include "rootston/keyboard.h"
 #include "rootston/seat.h"
+#include "rootston/text_input.h"
 #include "rootston/xcursor.h"
 
 
@@ -605,6 +606,8 @@ struct roots_seat *roots_seat_create(struct roots_input *input, char *name) {
 		return NULL;
 	}
 
+	roots_input_method_relay_init(seat, &seat->im_relay);
+
 	wl_list_insert(&input->seats, &seat->link);
 
 	seat->new_drag_icon.notify = roots_seat_handle_new_drag_icon;
@@ -1182,6 +1185,7 @@ void roots_seat_set_focus(struct roots_seat *seat, struct roots_view *view) {
 	if (view == NULL) {
 		seat->cursor->mode = ROOTS_CURSOR_PASSTHROUGH;
 		wlr_seat_keyboard_clear_focus(seat->seat);
+		roots_input_method_relay_set_focus(&seat->im_relay, NULL);
 		return;
 	}
 
@@ -1220,6 +1224,8 @@ void roots_seat_set_focus(struct roots_seat *seat, struct roots_view *view) {
 	if (seat->cursor) {
 		roots_cursor_update_focus(seat->cursor);
 	}
+
+	roots_input_method_relay_set_focus(&seat->im_relay, view->wlr_surface);
 }
 
 /**