[Tarantool-patches] [PATCH msgpuck 0/2] MP_EXT virtual serializer

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

The patchset makes MP_EXT serializer for mp_snprint() and
mp_fprint() functions virtual.

The patch implements one possible solution - return recursion
instead of mp_stack into the printers, and make external code
overload both mp_fprint() and mp_snprint(). The most
straightforward solution.

However it is possible to avoid overloading both mp_fprint() and
mp_snprint(). Instead, msgpuck could expose just one virtual
method, which takes an opaque object with method print() having
signature like snprintf() and fprintf() - format and arguments.

mp_snprint() would create that opaque object's print() method as
snprintf(). While mp_fprint() would create this object's print()
method as fprintf(). Drawback of the solution - ton of virtual
calls, because serializers tend to call print() a lot, on small
strings like ':', ', ', and so on. On the other hand, this should
simplify code in Tarantool, especially MP_ERROR serializer, where
code duplication was so big for mp_snprint_error() and
mp_fprint_error(), that I invented some kind of C template for it.

With one virtual method, which accepts a virtual object it would
be just one mp_print_error().

I decided to leave the final decision to a review discussion.
Should we keep it like it is done now, or make it even more
virtual like I described above, or probably there are other ideas.

Branch: http://github.com/tarantool/msgpuck/tree/gerold103/mp_print_ext
Issue: https://github.com/tarantool/tarantool/issues/4719

Vladislav Shpilevoy (2):
  Return recursion to mp_snprint() and mp_fprint()
  Make MP_EXT mp_snprint() and mp_fprint() customizable

 msgpuck.c      | 156 ++++++++++++++++++++++++++++++++-----------------
 msgpuck.h      |  50 ++++++++++++++++
 test/msgpuck.c |  83 +++++++++++++++++++++++++-
 3 files changed, 234 insertions(+), 55 deletions(-)

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