Re: [anjuta-devel] New project interface and introspection

[Sébastien Granjoux <seb sfo free fr>]

Hi Abderrahim,


Le 05/09/2010 15:05, Abderrahim Kitouni a écrit :
> I don't think this is ok. "the object doesn't belong to the caller"
> means that the caller doesn't need to free it, which is wrong IMHO.

I'm quite sure it's right. One of the scary warning that you get when 
you return a C structure ask you to set transfer mode to none because 
the caller doesn't know how to free the structure.


> Yes, a gpointer parameter gets passed a python object as is, you just
> need to add some get_extra_data function or something.

I have tried this but how can I get back the object in python ?

I have defined in C
AnjutaProjectGObjectNode*
anjuta_project_generic_node_new (AnjutaProjectNodeType type, GFile 
*file, const gchar *name, gpointer user_data)

gpointer
anjuta_project_generic_node_get_user_data (AnjutaProjectNode *node);


I have written in python

class NodeData:
        def __init__(self):
                self.data = 0

data = NodeData()
node = Anjuta.project_generic_node_new (0, None, "noname", data)
pointer = Anjuta.project_generic_node_get_user_data (node)

But pointer is gi.FunctionInfo, how can I convert it back to NodeData ?


> > 2. I can try to check what is the difference between creating a
> > AnjutaProjectNode like it is now and a GObject representing a node.

I have try to create and free 1000000 project nodes using the current C 
structure or a GObject. It's roughly 2.5 time slower with GObject which 
is faster than what I expect.

If I'm doing the same in python it's 250 time slower for C structure and 
could be almost 160 time slower with GObject. The issue with GObject in 
python is that the finalize function is never called. Do you know how I 
can be sure that the free function is called ?

I have tried:
        node = Anjuta.ProjectGObjectNode.new (0, None, "noname", 0)
        node = None
Or
        node = Anjuta.ProjectGObjectNode.new (0, None, "noname", 0)
        node.free ()
This last piece of code give an error, because python is not aware that 
node shouldn't be used after calling node.free.


I haven't decided if I will use GObject for project node, here is a 
summarize of all issues.

1. Use C structures
+ Already working fine
+ No need to rewrite GNode functions
+ 2.5 faster than GObject (for very simple node)
- free function has to be called manually even in language with a GC

2. Use of a Boxed type
+ Same advantage than C structure
- I don't know if I can define a boxed type incrementing the reference 
count on copy and decrease it on free.
- I don't know if I can use this type in introspection annotation 
without changing the C code.

3. Use GObject
+ Deallocation can be done automatically in language like python
+ AnjutaProjectNode and AnjutaProjectNodeData are the same
+ Nodes could replace the project object.
- 2.5 slower than C structures
- Need to rewrite all GNode functions

What do you think ?


Regards,

Sébastien