1 files changed, 188 insertions, 0 deletions
diff --git a/kwin-type.c b/kwin-type.c
new file mode 100644
index 0000000..00f2369
--- /dev/null
+++ b/kwin-type.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2026 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#define _GNU_SOURCE
+#include <err.h>
+#include <locale.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <wchar.h>
+#include <wayland-client.h>
+#include <xkbcommon/xkbcommon.h>
+
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
+
+/* https://invent.kde.org/libraries/plasma-wayland-protocols/-/blob/master/src/protocols/fake-input.xml */
+static const struct wl_message input_methods[] = {
+	{ "authenticate", "ss", NULL },
+	{ "pointer_motion", "ff", NULL },
+	{ "button", "uu", NULL },
+	{ "axis", "uf", NULL },
+	{ "touch_down", "2uff", NULL },
+	{ "touch_motion", "2uff", NULL },
+	{ "touch_up", "2u", NULL },
+	{ "touch_cancel", "2", NULL },
+	{ "touch_frame", "2", NULL },
+	{ "pointer_motion_absolute", "3ff", NULL },
+	{ "keyboard_key", "4uu", NULL },
+	{ "destroy", "5", NULL },
+	{ "keyboard_keysym", "6uu", NULL },
+};
+static const struct wl_interface input_interface = { "org_kde_kwin_fake_input", 6, ARRAY_SIZE(input_methods), input_methods, 0, NULL };
+
+/* https://invent.kde.org/libraries/plasma-wayland-protocols/-/blob/master/src/protocols/keystate.xml */
+static const struct wl_message state_methods[] = { { "fetchStates", "", NULL } };
+static const struct wl_message state_events[] = { { "stateChanged", "uu", NULL } };
+static const struct wl_interface state_interface = { "org_kde_kwin_keystate", 1, ARRAY_SIZE(state_methods), state_methods, ARRAY_SIZE(state_events), state_events };
+enum { AUTHENTICATE = 0, KEY = 10, DESTROY = 11, KEYSYM = 12 };
+enum { RELEASED = 0, PRESSED = 1, CAPS_LOCK_KEY = 58 };
+
+static volatile sig_atomic_t interrupted;
+
+static void on_signal(int signo)
+{
+	interrupted = signo;
+}
+
+static void state_changed(void *data, struct wl_proxy *, uint32_t key, uint32_t state)
+{
+	bool **caps = data;
+	if (key == 0) {
+		*caps[0] = true;
+		*caps[1] = state != 0;
+	}
+}
+
+static void registry_global(void *data, struct wl_registry *, uint32_t name, const char *interface, uint32_t version)
+{
+	uint32_t **names = data;
+	if (!strcmp(interface, input_interface.name) && version >= (uint32_t)input_interface.version)
+		*names[0] = name;
+	else if (!strcmp(interface, state_interface.name))
+		*names[1] = name;
+}
+
+static void registry_global_remove(void *, struct wl_registry *, uint32_t)
+{
+}
+
+static void type_key(struct wl_proxy *input, uint32_t request, uint32_t key)
+{
+	wl_proxy_marshal_flags(input, request, NULL, input_interface.version, 0, key, PRESSED);
+	wl_proxy_marshal_flags(input, request, NULL, input_interface.version, 0, key, RELEASED);
+}
+
+int main(int argc, char **argv)
+{
+	bool caps_known = false, caps_locked = false, restore_caps = false, ret = false;
+	uint32_t input_name = 0, keystate_name = 0;
+	struct wl_proxy *input, *keystate;
+	struct wl_registry *registry;
+	struct wl_display *display;
+	xkb_keysym_t keysym;
+	wint_t cp;
+
+	if (argc != 1)
+		errx(1, "usage: %s < text.txt", argv[0]);
+	if (!setlocale(LC_CTYPE, "C.UTF-8"))
+		errx(1, "cannot select C.UTF-8 locale");
+	if (sigaction(SIGINT, &(struct sigaction){ .sa_handler = on_signal }, NULL) < 0 ||
+	    sigaction(SIGTERM, &(struct sigaction){ .sa_handler = on_signal }, NULL) < 0 ||
+	    sigaction(SIGHUP, &(struct sigaction){ .sa_handler = on_signal }, NULL) < 0) {
+		warn("installing signal handlers");
+		goto err;
+	}
+
+	display = wl_display_connect(NULL);
+	if (!display) {
+		warn("cannot connect to display");
+		goto err;
+	}
+	registry = wl_display_get_registry(display);
+	if (!registry) {
+		warn("getting registry");
+		goto err_display;
+	}
+	wl_registry_add_listener(registry,
+				 &(const struct wl_registry_listener){ registry_global, registry_global_remove },
+				 (uint32_t *[]){ &input_name, &keystate_name });
+	if (wl_display_roundtrip(display) < 0) {
+		warn("synchronizing display");
+		goto err_registry;
+	}
+	if (!input_name || !keystate_name) {
+		warnx("%s-v%d and %s-v%d protocols are required",
+		      input_interface.name, input_interface.version, state_interface.name, state_interface.version);
+		goto err_registry;
+	}
+	keystate = wl_registry_bind(registry, keystate_name, &state_interface, state_interface.version);
+	if (!keystate) {
+		warn("binding key-state interface");
+		goto err_registry;
+	}
+	wl_proxy_add_listener(keystate,
+			      (void (*[])(void)){ (void (*)(void))state_changed },
+			      (bool *[]){ &caps_known, &caps_locked });
+	input = wl_registry_bind(registry, input_name, &input_interface, input_interface.version);
+	if (!input) {
+		warn("binding fake-input interface");
+		goto err_keystate;
+	}
+	wl_proxy_marshal_flags(input, AUTHENTICATE, NULL, input_interface.version, 0, "kwin-type", "Type text from stdin");
+	wl_proxy_marshal_flags(keystate, 0, NULL, state_interface.version, 0);
+	if (wl_display_roundtrip(display) < 0) {
+		warn("synchronizing display");
+		goto err_input;
+	}
+	if (!caps_known) {
+		warnx("cannot read caps lock state");
+		goto err_input;
+	}
+
+	/* Chrome has some complicated keyboard refreshing logic. We could patch upstream kwin to
+	 * hack around it, or fix Chrome itself, but it's probably easier to just delay briefly
+	 * here. Probably other things will benefit from this hack too. Oh well. */
+	nanosleep(&(struct timespec){ .tv_nsec = 100000000 }, NULL);
+
+	if (interrupted)
+		goto err_input;
+	if (caps_locked) {
+		restore_caps = true;
+		type_key(input, KEY, CAPS_LOCK_KEY);
+	}
+
+	while (!interrupted && (cp = fgetwc(stdin)) != WEOF) {
+		if (interrupted)
+			break;
+		keysym = xkb_utf32_to_keysym(cp);
+		if (keysym == XKB_KEY_Linefeed)
+			keysym = XKB_KEY_Return;
+		type_key(input, KEYSYM, keysym);
+	}
+	if (!interrupted && ferror(stdin))
+		warn("reading stdin");
+	else
+		ret = true;
+
+err_input:
+	if (restore_caps)
+		type_key(input, KEY, CAPS_LOCK_KEY);
+	wl_proxy_marshal_flags(input, DESTROY, NULL, input_interface.version, WL_MARSHAL_FLAG_DESTROY);
+	if (wl_display_roundtrip(display) < 0) {
+		warn("synchronizing display");
+		ret = false;
+	}
+err_keystate:
+	wl_proxy_destroy(keystate);
+err_registry:
+	wl_registry_destroy(registry);
+err_display:
+	wl_display_disconnect(display);
+err:
+	return interrupted ? (128 + interrupted) : (ret ? 0 : 1);
+}