GObject Introspection from Python: inf_io_add_watch: socket gets passed integer value instead of pointer.

[vasiliyl]

I'm trying to rewrite inf-test-browser in python using gobject introspection and what I've encountered looks like a bug. Here is snippet code:

from gi.repository import Infinity

io = Infinity.StandaloneIo.new()
io.add_watch(0, Infinity.IoEvent.INCOMING | Infinity.IoEvent.ERROR, lambda *args, **kwargs: None, None)
io.add_watch(0xBEEF, Infinity.IoEvent.INCOMING | Infinity.IoEvent.ERROR, lambda *args, **kwargs: None, None)

I've added printf("%p\n", socket); to add_io_watch to confirm my guess and here is the output:

socket = (nil)

** (process:30884): CRITICAL **: inf_io_add_watch: assertion 'socket != NULL' failed
socket = 0xbeef
zsh: segmentation fault

I'm using python3 if that matters.

[aburgm]

Hi,

nice to see you playing around with the gobject introspection bindings! Indeed when I added gobject introspection for libinfinity, I did not check whether the complete API is usable from the bindings, and I am aware there are several rough edges. For example InfcNotePlugin and InfdNotePlugin are likely problematic as well. So if you go forward please let me know if you run into other issues or oddities.

The problem with add_watch is that in the C API a pointer to the file descriptor is used, and gobject-introspection/Python does not really know what to with it. The API is somewhat binding-unfriendly since it requires the caller to manage the lifetime of that int pointer. The original reason for this is that I wanted the API to be independent from the native representation of a network socket, whether it is an int or a SOCKET (on Windows; but this is actually just an integer as well), or something completely different. In practise that is probably rather irrelevant, but it is what it is at the moment.

I have added a new method add_watch_from_fd(), which allows to give an integer instead of a pointer, and which makes the InfIo object take care of the lifetime. The callback function gets an array with a single entry that is the file descriptor, since that was an easy way to get gobject-introspection to deal with the pointer parameter. I might want to change this in the future to a function that extracts the integer fd from the callback parameter, though. For now, if you update to master and replace add_watch by add_watch_from_fd, things should work fine.

[vasiliyl]

Great, thanks a lot!

I'll keep you informed about my progress.