我正在尝试调用该方法并使用 dbus 低级 API 在 dbus 上ReadLocalBdAddrReq接收其信号。ReadLocalBdAddrCfm
我在一些论坛帖子和 dbus 教程的帮助下编写了以下代码。
问题是，我无法接收回信号。代码在某些地方不完整，因为我不知道应该做什么。
所以请帮助我，以便我可以接收所调用方法的信号。这里是我写的代码。请纠正我犯的任何错误。
#include <stdlib.h>
#include <stdio.h>
#include <dbus/dbus.h>
#define OBJ_PATH "/bt/cm"
static dbus_bool_t add_watch(DBusWatch *watch, void *data)
{
if (!dbus_watch_get_enabled(watch))
return TRUE;
int fd = dbus_watch_get_unix_fd(watch);
unsigned int flags = dbus_watch_get_flags(watch);
int f = 0;;
if (flags & DBUS_WATCH_READABLE) {
f |= DBUS_WATCH_READABLE;
printf("Readable\n");
}
if (flags & DBUS_WATCH_WRITABLE) {
printf("Writeable\n");
f |= DBUS_WATCH_WRITABLE;
}
/* this should not be here */
if (dbus_watch_handle(watch, f) == FALSE)
printf("dbus_watch_handle() failed\n");
return TRUE;
}
static void remove_watch(DBusWatch *watch, void *data)
{
printf("In remove watch with fd = [%d]\n",dbus_watch_get_unix_fd(watch));
}
static void toggel_watch(DBusWatch *watch, void *data)
{
printf("In toggel watch\n");
/*
if (dbus_watch_get_enabled(watch))
add_watch(watch, data);
else
remove_watch(watch, data);
*/
}
/* timeout functions */
static dbus_bool_t add_time(DBusTimeout *timeout, void *data)
{
/* Incomplete */
printf("In add_time\n");
if (!dbus_timeout_get_enabled(timeout))
return TRUE;
//dbus_timeout_handle(timeout);
return 0;
}
static void remove_time(DBusTimeout *timeout, void *data)
{
/* Incomplete */
printf("In remove_time\n");
}
static void toggel_time(DBusTimeout *timeout, void *data)
{
/* Incomplete */
printf("In toggel_time\n");
/*
if (dbus_timeout_get_enabled(timeout))
add_timeout(timeout, data);
else
remove_timeout(timeout, data);
*/
}
/* message filter -- handlers to run on all incoming messages*/
static DBusHandlerResult filter (DBusConnection *connection, DBusMessage *message, void *user_data)
{
printf("In filter\n");
char *deviceaddr;
if (dbus_message_is_signal(message, "com.bluegiga.v2.bt.cm", "ReadLocalBdAddrCfm")) {
printf("Signal received is ReadLocalBdAddrCfm\n");
if ((dbus_message_get_args(message,NULL,DBUS_TYPE_STRING, &deviceaddr,DBUS_TYPE_INVALID) == FALSE))
{
printf("Could not get the arguments from the message received\n");
return -2;
}
printf("Got Signal and device address is [%s]\n", deviceaddr);
}
return 0;
}
/* dispatch function-- simply save an indication that messages should be dispatched later, when the main loop is re-entered*/
static void dispatch_status(DBusConnection *connection, DBusDispatchStatus new_status, void *data)
{
printf("In dispatch_status\n");
if (new_status == DBUS_DISPATCH_DATA_REMAINS)
{
printf("new dbus dispatch status: DBUS_DISPATCH_DATA_REMAINS [%d]",new_status);
}
}
/* unregister function */
void unregister_func(DBusConnection *connection, void *user_data)
{
}
/* message function - Called when a message is sent to a registered object path. */
static DBusHandlerResult message_func(DBusConnection *connection, DBusMessage *message, void *data)
{
printf("Message [%s] is sent to [%s] from interface [%s] on path [%s] \n",dbus_message_get_member(message),dbus_message_get_destination(message),
dbus_message_get_interface(message),dbus_message_get_path(message)); return 0;
}
DBusObjectPathVTable table = {
.unregister_function = unregister_func,
.message_function = message_func,
};
int main(void) {
DBusMessage* msg;
DBusMessageIter args;
DBusConnection* conn;
DBusError err;
DBusPendingCall* pending;
int ret;
//unsigned int level;
char* appHandle = NULL;
//int *context;
int msg_serial;
int open;
char *deviceaddr;
dbus_error_init(&err);
// connect to the system bus and check for errors
conn = dbus_bus_get(DBUS_BUS_SYSTEM, &err);
if (dbus_error_is_set(&err)) {
fprintf(stderr, "Connection Error (%s)\n", err.message);
dbus_error_free(&err);
}
if (NULL == conn) {
exit(1);
}
if (!dbus_connection_set_watch_functions(conn, add_watch, remove_watch, toggel_watch, NULL, NULL))
{
printf("Error in dbus_set_watch_functions\n");
dbus_connection_unref(conn);
return -1;
}
/* These functions are responsible for making the application's main loop aware of timeouts */
if (!dbus_connection_set_timeout_functions(conn, add_time, remove_time, toggel_time, NULL, NULL))
{
printf("Error in dbus_set_timeout_functions\n");
dbus_connection_unref(conn);
return -1;
}
/* Used to register the handler functions run on incoming messages*/
if (!dbus_connection_add_filter(conn, filter, NULL, NULL))
{
printf("Error in adding filter\n");
dbus_connection_unref(conn);
return -1;
}
/* Filter added for incoming messages */
/* Set a function to be invoked when the dispatch status changes */
dbus_connection_set_dispatch_status_function(conn, dispatch_status, NULL ,NULL);
/* Register a handler for messages sent to a given path */
if(!dbus_connection_register_object_path(conn, OBJ_PATH, &table, NULL))
{
printf("Error in registering object\n");
return -1;
}
/* sending messages to the outgoing queue */
msg = dbus_message_new_method_call("com.bluegiga.v2.bt.cm", // target for the method call
OBJ_PATH, // object to call on
"com.bluegiga.v2.bt.cm", // interface to call on
"ReadLocalBdAddrReq"); // method name
if (NULL == msg) {
fprintf(stderr, "Message Null\n");
exit(1);
}
dbus_message_iter_init_append(msg, &args);
if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_UINT16,&appHandle)) {
fprintf(stderr, "Out Of Memory!\n");
exit(1);
}
fprintf(stderr, "Sending the connections\n");
// send message and get a handle for a reply
if (!dbus_connection_send (conn, msg, &msg_serial)) {
fprintf(stderr, "Out Of Memory!\n");
exit(1);
}
fprintf(stderr, "Connection sent and the msg serial is %d\n",msg_serial);
/* Message sent over */
/* not sure whether this should be here or above watch */
while (dbus_connection_get_dispatch_status(conn) == DBUS_DISPATCH_DATA_REMAINS)
{
//printf("Entered in dispatch\n");
/* Processes any incoming data. will call the filters registered by add_filer*/
dbus_connection_dispatch(conn);
}
return 0;
}
运行此程序后，它具有以下输出：
可读
发送连接
已发送连接且消息序列为 2(DBUS_MESSAGE_TYPE_METHOD_RETURN)
如果连接被发送到对象路径，那么message_func应该被正确调用，但它永远不会被调用。我在发送方法调用时犯了任何错误吗？