On Tue, 2008-09-09 at 18:00 +0200, Patrick Ohly wrote: > On Tue, 2008-09-09 at 09:12 -0400, IGnatius T Foobar wrote: > > Chenthill wrote: > > > So it is better to inform all the stake holders about the change and let > > > them depend on the library versions to decide whether to free the memory > > > or not if they have a need to depend on the older versions of libical. I > > > think no one deny to make the necessary changes knowing that the old API > > > is not very stable. > > > > > > Atleast once I noticed the problem. I made this patch and made all the > > > changes required in evolution, evolution-exchange and > > > evolution-data-server. I would not really like to change them again with > > > new APIS :) > > Although I agree that the new memory model is a vast improvement over > > the existing one, I think you may be underestimating the potential > > effects of telling dozens of downstream projects that they will have to > > rewrite their code *right* *now* in order to continue using libical. > > Many will respond by forking, or staying forked, which as I mentioned > > earlier is exactly the opposite of what we are trying to accomplish. > > I agree. When I started writing the patch, since only the gnome packages which depend on libecal are going be affected. I thought of incorporating changes in all other modules myself since it was just to grep all the apis and free the returned memory.
So I had a thinking that all the downstream projects would be ready to change their code during a release time since stability is an issue and change can be done fast. But if it was not the case and might result in forking again, the only solution which I too see is create a new set of API's which uses the new memory allocation. > > > How would you feel about a global flag which tells libical how to > > allocate memory? > > The problem with that is that it is not possible to mix code which uses > the old and the new semantic. For example, a program or library which > uses libical directly, using the old semantic, couldn't be combined with > the Evolution libraries. Yes right. Its not possible to have the old semantic with changed memory allocation. > > To let old and new code coexists I would suggest the following approach: > 1. The Evolution patch gets applied, making the core functions safe > to use. > 2. The function implementations whose semantic has changed get > renamed; I kind of like the _r suffix, but _alloc or _copy would > also work. > 3. Under the old names small wrappers are added which establish the > old behavior again by copying the string into the ring buffer > and freeing the dynamically allocated one: this incurs some > overhead, but usage of these versions of the calls is > discouraged anyway. By using function attributes it would be > possible to trigger deprecation warnings for code which still > uses them. > 4. In the header file both variants are declared. > 5. In addition, ical.h also redefines the old names to the new > names if the HANDLE_LIBICAL_MEMORY define is set: Evolution code > already does that and therefore continues to work with such a > modified upstream libical without source code changes. > > I personally would prefer to avoid step 5 and rather do a search/replace > in Evolution, but Chenthill didn't like that. Since we do really want to remove the fork and pick up packages from upstream, I can change the apis in evolution related packages if a new set of apis with some suffix is provided from libical upstream. The old patch is attached with bug 516408. You can find the patches at, http://svn.gnome.org/viewvc/libical?view=revision&revision=633 and http://svn.gnome.org/viewvc/libical?view=revision&revision=637 thanks, Chenthill. _______________________________________________ Evolution-hackers mailing list Evolutionemail@example.com http://mail.gnome.org/mailman/listinfo/evolution-hackers