Re: [Evolution-hackers] Re: [evolution-patches] patch for bug 48466



On Mon, 2003-09-15 at 22:32 +0800, Charles Zhang wrote:
Thank you, Not Zed.
I think it's necessary to do so.

First, in the existing code structure, it often do remove an item more than once.
Because in the result of function gnome_iconlist_get_selection(), the return GList contains the index of the selected item.
But in this index list, the item index information is duplicated if you pressed 'CTRL' while selecting item (from unselected state) in the iconlist widget.
For example, you insert three attachments, select the first one, then multi-select the second one(PRESS CTRL WHILE DOING IT).
Thus you get the all three selected, and if you right click one of the two selected icons and use the "remove" submenu, then these three all disappear because what the function gnome_iconlist_get_selection() return is 011, but not 01.
I don't know if I have showed it clearly enough. My libgnomeui's version is 2.2.2-6.

Ok, well i confirmed this.  But this is definetly a bug in gnome icon list, which should be fixed/relayed upstream.

Could you create a bug in gnome bugzilla about it, and reference the bug in the code, saying exactly why the code works that way?

If you keep control-clicking an icon and leave it in the selected state when you do a remove, the number gets added again and again.

Secondly, I think the existing code is less efficient, because it makes another list, this is not necessary.
Why it makes this list, I'll coming to that in the third reason.

The third, in the existing code, the author uses two loop parts to complete the remove action, he cannot do this remove action with one loop because what the function gnome_iconlist_get_selection() return is the index of the selected icon. So if he removes the item, the other icon's index is not the order it has been. Thus he convert the index to the pointer of the real object in the first loop part, and remove them in the second loop part. If we use this list_reverse() function, we don't have to consider the order at all.

Well that is not true.  You are considering order, list-reverse is a re-ordering method, and only works because you are making assumptions about the order of the data returned from the icon list, and how it relates to the selection.  You are making big unpublished assumptions about how removing an item will affect the selection indices.

It is the original code that isn't considering order at all.

The fourth,  because the  gnome_iconlist_get_selection() function return the duplicated information of the selected item' index (maybe it has been updated or fixed in libgnomeui's new version, but we should have all versions work.), we should check the item index in the loop part to see if it has been removed.

Again this only works assuming the assumption about the order of indices is correct.  Which is ok, only if clearly marked, and indicating it's a workaround.

Finally, we can easily get the dialog struct, but I cannot get it's wrapper struct and free it. Then I have to use this method to get us free the DialogData struct defined in line 283(e-msg-composer-attachment.c).

Huh?  there's nothing wrong there, except use destroy instead of forcing a close signal on the dialogue, which isn't the way it should be done.

Anyway, having said that:
- it's an icon list bug with specific behaviour
- submit a bug (and patch if possible) for the icon list
- make it very clear in the code that this is a workaround for a bug, via a comment
- don't remove the existing 'this is a mess' comment - the same applies to the new code, if it still applied to the code you removed, since they're both doing the same messy stuff.
- use widget_destroy rather than forcing a response signal, infact ,move that logic into remove_attachment() anyway.

Z



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