【发布时间】：2017-11-09 02:33:31
【问题描述】：
最近使用dbus作为IPC，但遇到一些问题：
-
如何处理发送消息失败：
dbus_connection_send可以发送dbus消息，但是文档说：因为这只会对消息进行排队，所以它失败的唯一原因是 记忆力不足。即使断开连接也不会出错 被退回。如果函数由于内存不足而失败，则返回 错误的。该功能永远不会因其他原因而失败；即使 连接已断开，但您可以将传出消息排队 显然不会发送。
那么当连接断开时如何处理这种情况，以确保传出队列中的所有消息都发送成功
dbus_connection_dispatch收到消息时如何处理断开连接，我的代码是这样的，但是我认为重新连接到dbus时会丢失一些消息
void DbusMessageWrapper::messageDispatchThreadFunction() { 开始： 结构 pollfd *pollFd = &m_pollFd; if (!dbus_connection_set_watch_functions(m_dbusConnection, addWatch, removeWatch, NULL, this, NULL)) { TONLY_ERROR("dbus_connection_set_watch_functions 失败"); 返回; }
if (!dbus_connection_add_filter(m_dbusConnection, messageProcessFunction, this, NULL))
{
TONLY_INFO("dbus_connection_add_filter failed");
return;
}
int iret = 0;
for (; !m_isShuttingDown;)
{
iret = poll(pollFd, 1, -1);
if (iret < 0)
{
///If poll return -1, we think that poll does not work on current plateform, so emit a ALERT log and exit application
TONLY_ALERT("poll for dbus fd failed, the application will exit.");
exit(1);
}
/**
* If poll return POLLHUP/POLLRDHUP/POLLERR event, we think the dbus connection have disconnected from dbus deamon
* we should release the request name and close current dbus connection, then reconnect to the dbus deamon,
* aslo add the message observer watch to dbus connection again
*/
if ((pollFd->revents & POLLHUP) || (pollFd->revents & POLLRDHUP) || (pollFd->revents & POLLERR))
{
TONLY_ERROR("poll error event occured, will reconnect to dbus deamon.");
dbusDisConnect();
dbusConnect();
///reinstall the message observer
auto observers = m_observers;
m_observers.clear();
for (auto it = observers.begin(); it != observers.end(); it++)
{
addMessageObserver({it->second});
}
goto start;
}
unsigned int flags = 0;
if (pollFd->revents & POLLIN)
{
flags |= DBUS_WATCH_READABLE;
}
///wait for there are enougth memory
while (!dbus_watch_handle(m_watch, flags))
{
TONLY_ERROR("Dbus need more memory");
sleep(1);
}
while (dbus_connection_get_dispatch_status(m_dbusConnection) == DBUS_DISPATCH_DATA_REMAINS)
{
dbus_connection_dispatch(m_dbusConnection);
}
}
}
【问题讨论】：
标签： dbus