[Geany-Devel] Problem with a plugin I'm working on

Colomban Wendling lists.ban at xxxxx
Wed Apr 3 13:29:14 UTC 2013

Le 03/04/2013 15:08, Nick Treleaven a écrit :
> On 02/04/2013 22:53, Steven Blatnick wrote:
>> I've started writing some plugins for geany on github, but I'm running
>> into a problem.  C is not my language of expertise, so I thought I would
>> see if I'm just doing something stupid.
>> *The Problem:*
>> The basic problem is that I have a struct I'm using to pass information
>> around like an object, but the information isn't staying with the struct
>> when retrieving it from a TreeView.
> I think the problem is this line:
>     list = gtk_tree_store_new(1, G_TYPE_STRING);
> later:
> Tool *tool
> ...
> gtk_tree_store_set(list, &row, 0, tool, -1);
> You should probably be using G_TYPE_POINTER instead of G_TYPE_STRING.
> [...]

Yep that's likely to be the issue.

>> Also, one of the things I love about Geany is how little memory it uses,
>> so feel free to give me pointers on when I need to free up memory,
>> because I don't want my code to leak.
> Well, I didn't study your code for long, but:
> Tool *tool = g_slice_new(Tool);
> Somehow you need to g_slice_free(Tool, tool) for each call to
> g_slice_new. Maybe by iterating the tree store when you've finished
> using it.

Yes.  Actually in delete_tool() you call g_free() on the tool, but
although the idea is correct (freeing the memory) you *MUST* use
g_slice_free() to free memory allocated with g_slice_{alloc,new}().
GSlice is a separate allocator, so you can't use g_free() on memory you
allocated with it.

You should probably add a new function next to new_tool() (e.g.
free_tool()) that deals with freeing the memory for that tool, just the
opposite of new_tool().

Also, you should always allocate the memory for the tool->name, and
always free it before setting it.  Here you have a leak in on_change():
g_strdup() allocate a copy of the string, but you don't free the old
one.  And you can only free the old one if it was allocated, so you need
to make sure you always allocate it (e.g. in new_tool() you set
tool->name = g_strdup(_("New tool"))), and in free_tool() you
g_free(tool->name).  And of course in on_change(), you g_free()
tool->name before setting it to the new value.


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