[PATCH 13/14] rbtree.h: Added WINE_RB_FOR_EACH_DESTRUCTOR and WINE_RB_FOR_EACH_ENTRY_DESTRUCTOR helpers for implementing tree destructors.

[Jacek Caban]

On 14.02.2017 16:21, Matteo Bruni wrote:
> 2017-02-13 21:12 GMT+01:00 Jacek Caban <jacek at codeweavers.com>:
>> Signed-off-by: Jacek Caban <jacek at codeweavers.com>
>> ---
>>  include/wine/rbtree.h | 20 ++++++++++++++------
>>  1 file changed, 14 insertions(+), 6 deletions(-)
> These sound like the _SAFE variants of our list implementation. Any
> reason not to use the same naming here?

I thought about it. I think that there are different meanings of safety:

1. safe to free current entry (but not necessarily safe to call
wine_rb_remove on it)
2. safe to cause tree mutation like call wine_rb_put or wine_rb_remove
on any other element than current one
3. safe to remove current element (and possibly free it later)

The variant that I implemented is safe only as in (1), while current
WINE_RB_FOR_EACH is safe as in (2).

By analogy, list _SAFE macros are safe as in (3) - you can remove
current element, but generally shouldn't remove random other ones,
because it may be the stored next entry. Also you need to remove element
from the list before freeing it. I wanted to preserve that name if we
ever find a need for macro safe as in (3) in rb tree. Its implementation
for rb trees would look like the one I sent, except it would use regular
order instead of postorder.

That said, I'm happy to rename it if you think there is a better name. I
just think that _SAFE is not the right one.

Thanks,
Jacek