2016-09-25 4:37 GMT+02:00 Carsten Haitzler <ras...@rasterman.com>:
> On Sat, 24 Sep 2016 18:44:28 +0200 Davide Andreoli <d...@gurumeditation.it
> >
> said:
>
> > 2016-09-24 12:59 GMT+02:00 Carsten Haitzler <ras...@rasterman.com>:
> >
> > > On Sat, 24 Sep 2016 12:43:03 +0200 Davide Andreoli <
> d...@gurumeditation.it
> > > >
> > > said:
> > >
> > > > 2016-09-24 7:14 GMT+02:00 Carsten Haitzler <ras...@rasterman.com>:
> > > >
> > > > > On Fri, 23 Sep 2016 17:24:17 -0700 Cedric BAIL <
> cedric.b...@free.fr>
> > > said:
> > > > >
> > > > > > On Fri, Sep 23, 2016 at 10:48 AM, Davide Andreoli
> > > > > > <d...@gurumeditation.it> wrote:
> > > > > > > 2016-09-21 4:35 GMT+02:00 Felipe Magno de Almeida <
> > > > > > > felipe.m.alme...@gmail.com>:
> > > > > > >> On Sun, Sep 18, 2016 at 3:35 AM, Davide Andreoli <
> > > > > d...@gurumeditation.it>
> > > > > > >> wrote:
> > > > > > >> > 2016-09-18 4:30 GMT+02:00 Felipe Magno de Almeida <
> > > > > > >> > felipe.m.alme...@gmail.com>:
> > > > > > >> >> On Sep 17, 2016 3:53 AM, "Davide Andreoli" <
> > > d...@gurumeditation.it
> > > > > >
> > > > > > >> wrote:
> > > > > > >>
> > > > > > >> [snip]
> > > > > > >>
> > > > > > >> >> The problem with callbacks is not difficult to implement,
> but
> > > > > difficult
> > > > > > >> to
> > > > > > >> >> free the void* data. It needs two function pointers and the
> > > void*
> > > > > data
> > > > > > >> to
> > > > > > >> >> implement correctly and generally. Not that I'm against per
> > > se, but
> > > > > > >> >> lifetime is the real problem.
> > > > > > >> >
> > > > > > >> > Indeed the lifetime of the *void data is the trickiest
> part, a
> > > > > > >> free_data_cb
> > > > > > >> > seems to me the most "correct" way to handle this, not only
> for
> > > > > bindings
> > > > > > >> > but also for C code.
> > > > > > >> >
> > > > > > >> > Can you explain me how promises solve this problem? where
> the
> > > user
> > > > > is
> > > > > > >> > expected to free the *data in C? in both the success/failure
> > > > > callbacks?
> > > > > > >>
> > > > > > >> Promises are not generic, so their lifetime is known. The user
> > > frees
> > > > > it in
> > > > > > >> success/failure callback, yes.
> > > > > > >>
> > > > > > >
> > > > > > > ok, thanks for the explanation. So the user have to free the
> *data
> > > in
> > > > > both
> > > > > > > success and failure callbacks... this is error prone and
> repetitive
> > > > > for the
> > > > > > > user,
> > > > > > > I suggest instead to add a free_data cb, in this way the usage
> is
> > > > > simpler
> > > > > > > and
> > > > > > > it also correspond better with the promise_value_set that
> already
> > > have
> > > > > the
> > > > > > > free callback.
> > > > > >
> > > > > > Hum, we are talking about the data pointer given when
> registering the
> > > > > > callback right ? I guess it would make sense and simplify a lot
> of
> > > > > > code. Should we also apply that on efl.object events too ?
> > > > > >
> > > > > > In that case, if NULL is given, nothing will be done on the
> pointer.
> > > > > > Are we ok with this ?
> > > > >
> > > > > ummmm right now we provide in C a void * for cb data. what this is
> is
> > > > > unknown
> > > > > to efl and if you want a free cb we have to pass ANOTHER pointer
> to the
> > > > > free
> > > > > cb... and this also means STORING these ptrs too along with every
> cb.
> > > do we
> > > > > really want to spend this extra ptr? 8 bytes on 64bit... per cb...
> > > extra.
> > > > >
> > > > > i see the point, but i also see the cost. :/
> > > > >
> > > >
> > > > If we are really so much into optimization then promise should not
> be Eo
> > > > object at all :P
> > >
> > > difference - promises are temporary/transient and dont tend to stay
> around
> > > a
> > > lot. callbacks hang out on objects by the 1000's and hang out all day
> like
> > > a
> > > bad smell... :)
> > >
> > > >
> > > > >
> > > > > if we do this - we do this for promises AND efl events. must be
> > > > > symmetric/everywhere.
> > > >
> > > > I agree with this, we should probably provide a free_cb every time we
> > > > accept a void *data
> > >
> > > maybe we should use a whole struct that holds cb, data and free cb.
> maybe
> > > thats
> > > a bit much? like
> > >
> > > typedef struct _Efl_Callback Efl_Callback;
> > > typedef void (*Efl_Data_Free_Cb) (void *data);
> > >
> > > struct _Efl_Callback {
> > > Efl_Event_Cb func;
> > > const void *data;
> > > Efl_Data_Free_Cb data_free;
> > > };
> > >
> > > as now we have a "bag of data" that represents something to call, what
> to
> > > pas
> > > to it and how to clean up what is passed. it is a unit of data and so
> > > expressing it as a struct might make more sense, so now we
> > >
> > > Efl_Callback cb = {my_cb_func, my_cb_data, my_data_free};
> > > efl_callback_add(obj, EVENT_TYPE, &cb);
> > >
> > >
> > I cannot see the benefit of using a struct here... it's more chars to
> type
> > and more data
> > to store when more that one callback is used, like in efl_future_then(),
> > where
> > we have 3 callback pointers but just 1 *data and 1 data_free_cb
>
> well before it was 1 values always together. a func ptr + data ptr, now
> it's 3
> values. together. always. doesn't it make sense to start grouping them as a
> unit? i dislike havin to pass yet another NULL all the time too. the
> number of
> times that data pointer needs freeing is rather rare (in my experience).
>
I'm also not so happy to add yet another NULL to type, but I really cannot
see
how your proposal will improve things, especially for efl_future_then() :/
You want something like this?
f = efl_uri_set(url);
Efl_Callback cb1 = {my_done_cb, my_cb_data, my_cb_data_free}
Efl_Callback cb2 = {my_error_cb}
Efl_Callback cb3 = {my_progress_cb}
efl_future_then(f, cb1, cb2, cb3)
instead of this:
f = efl_uri_set(url);
efl_future_then(f, my_done_cb, my_error_cb, my_prog_cb, my_cb_data,
my_free_data)
You are confusing me :)
Another solution in my mind would be to leave efl_future_then as is (6
params) and
define an efl_then() variadic macro that accept from 3 to 6 args (I'm not
sure about the exact syntax here)
>
> --
> ------------- Codito, ergo sum - "I code, therefore I am" --------------
> The Rasterman (Carsten Haitzler) ras...@rasterman.com
>
>
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