godot/platform/linuxbsd/freedesktop_portal_desktop.cpp

/*************************************************************************/
/*  freedesktop_portal_desktop.cpp                                       */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
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#include "freedesktop_portal_desktop.h"

#ifdef DBUS_ENABLED

#include "core/error/error_macros.h"
#include "core/os/os.h"
#include "core/string/ustring.h"

#include "dbus-so_wrap.h"

#include "core/variant/variant.h"

#define BUS_OBJECT_NAME "org.freedesktop.portal.Desktop"
#define BUS_OBJECT_PATH "/org/freedesktop/portal/desktop"

#define BUS_INTERFACE_SETTINGS "org.freedesktop.portal.Settings"

static bool try_parse_variant(DBusMessage *p_reply_message, int p_type, void *r_value) {
	DBusMessageIter iter[3];

	dbus_message_iter_init(p_reply_message, &iter[0]);
	if (dbus_message_iter_get_arg_type(&iter[0]) != DBUS_TYPE_VARIANT) {
		return false;
	}

	dbus_message_iter_recurse(&iter[0], &iter[1]);
	if (dbus_message_iter_get_arg_type(&iter[1]) != DBUS_TYPE_VARIANT) {
		return false;
	}

	dbus_message_iter_recurse(&iter[1], &iter[2]);
	if (dbus_message_iter_get_arg_type(&iter[2]) != p_type) {
		return false;
	}

	dbus_message_iter_get_basic(&iter[2], r_value);
	return true;
}

bool FreeDesktopPortalDesktop::read_setting(const char *p_namespace, const char *p_key, int p_type, void *r_value) {
	if (unsupported) {
		return false;
	}

	DBusError error;
	dbus_error_init(&error);

	DBusConnection *bus = dbus_bus_get(DBUS_BUS_SESSION, &error);
	if (dbus_error_is_set(&error)) {
		dbus_error_free(&error);
		unsupported = true;
		if (OS::get_singleton()->is_stdout_verbose()) {
			ERR_PRINT(String() + "Error opening D-Bus connection: " + error.message);
		}
		return false;
	}

	DBusMessage *message = dbus_message_new_method_call(
			BUS_OBJECT_NAME, BUS_OBJECT_PATH, BUS_INTERFACE_SETTINGS,
			"Read");
	dbus_message_append_args(
			message,
			DBUS_TYPE_STRING, &p_namespace,
			DBUS_TYPE_STRING, &p_key,
			DBUS_TYPE_INVALID);

	DBusMessage *reply = dbus_connection_send_with_reply_and_block(bus, message, 50, &error);
	dbus_message_unref(message);
	if (dbus_error_is_set(&error)) {
		dbus_error_free(&error);
		dbus_connection_unref(bus);
		if (OS::get_singleton()->is_stdout_verbose()) {
			ERR_PRINT(String() + "Error on D-Bus communication: " + error.message);
		}
		return false;
	}

	bool success = try_parse_variant(reply, p_type, r_value);

	dbus_message_unref(reply);
	dbus_connection_unref(bus);

	return success;
}

uint32_t FreeDesktopPortalDesktop::get_appearance_color_scheme() {
	if (unsupported) {
		return 0;
	}

	uint32_t value = 0;
	read_setting("org.freedesktop.appearance", "color-scheme", DBUS_TYPE_UINT32, &value);
	return value;
}

FreeDesktopPortalDesktop::FreeDesktopPortalDesktop() {
#ifdef DEBUG_ENABLED
	int dylibloader_verbose = 1;
#else
	int dylibloader_verbose = 0;
#endif
	unsupported = (initialize_dbus(dylibloader_verbose) != 0);
}

#endif // DBUS_ENABLED