Обсуждение: [COMMITTERS] pgsql: Introduce convenience macros to hide JsonbContainer headeracces

Introduce convenience macros to hide JsonbContainer header accesses better.

This improves readability a bit and may make future improvements easier.

In passing, make sure that the JB_ROOT_IS_XXX macros deliver boolean (0/1)
results; the previous coding was a bug hazard, though no actual bugs are
known.

Nikita Glukhov, extended a bit by me

Discussion: https://postgr.es/m/9e21a39c-c1d7-b9b5-44a0-c5345a5029f6@postgrespro.ru

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/f7c62462402972b13d10e43f104ca0c0fecb6d08

Modified Files
--------------
src/backend/utils/adt/jsonb_util.c | 14 +++++++-------
src/backend/utils/adt/jsonfuncs.c  |  4 ++--
src/include/utils/jsonb.h          | 16 +++++++++++-----
3 files changed, 20 insertions(+), 14 deletions(-)