Tom Weber skrev 3/12/12 10:58 AM:
Another question regarding the channel data queue. Is there a risk that
we could miss incoming data which is received during the query-loop?
Imagine the following situation:
1. poll() indicates POLLIN on the session socket.
2. The application checks channel #1, no data is waiting.
3. The application checks channel #2, no data is waiting, but libssh2
receives data for channel #1.
4. poll() sits around waiting, while we need the channel #1 data to
carry on the conversation.
We have seen delays in traffic now and then, and I wonder if this is the
reason. If so, can you recommend a workaround? Looping one more time
wouldn't change the situation. A dirty workaround I can think of is to
register a snooping recv() callback and keep looping until recv() hasn't
received anything during a loop.
After looking at the API, I think I have found a solution.
libssh2_channel_window_read_ex() can check if there is data waiting on a
channel, without reading from the socket.
So we would have to run a libssh2_channel_window_read_ex() loop after
each libssh2_channel_read_ex() loop, and repeat both loops until
libssh2_channel_window_read_ex() returns zero for all channels.
--
Best Regards,
Tom Weber
Cryptzone Group AB
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