pgsql: Split tuptoaster.c into three separate files.

Split tuptoaster.c into three separate files.

detoast.c/h contain functions required to detoast a datum, partially
or completely, plus a few other utility functions for examining the
size of toasted datums.

toast_internals.c/h contain functions that are used internally to the
TOAST subsystem but which (mostly) do not need to be accessed from
outside.

heaptoast.c/h contains code that is intrinsically specific to the
heap AM, either because it operates on HeapTuples or is based on the
layout of a heap page.

detoast.c and toast_internals.c are placed in
src/backend/access/common rather than src/backend/access/heap. At
present, both files still have dependencies on the heap, but that will
be improved in a future commit.

Patch by me, reviewed and tested by Prabhat Sabu, Thomas Munro,
Andres Freund, and Álvaro Herrera.

Discussion: http://postgr.es/m/CA+TgmoZv-=2iWM4jcw5ZhJeL18HF96+W1yJeYrnGMYdkFFnEpQ@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/8b94dab06617ef80a0901ab103ebd8754427ef5a

Modified Files
--------------
doc/src/sgml/storage.sgml | 2 +-
src/backend/access/common/Makefile | 5 +-
src/backend/access/common/detoast.c | 869 ++++++++
src/backend/access/common/heaptuple.c | 4 +-
src/backend/access/common/indextuple.c | 9 +-
src/backend/access/common/reloptions.c | 2 +-
src/backend/access/common/toast_internals.c | 632 ++++++
src/backend/access/heap/Makefile | 2 +-
src/backend/access/heap/heapam.c | 2 +-
src/backend/access/heap/heapam_handler.c | 2 +-
src/backend/access/heap/heaptoast.c | 917 ++++++++
src/backend/access/heap/rewriteheap.c | 2 +-
src/backend/access/heap/tuptoaster.c | 2419 ----------------------
src/backend/access/transam/xlog.c | 2 +-
src/backend/commands/analyze.c | 2 +-
src/backend/commands/cluster.c | 2 +-
src/backend/executor/execExprInterp.c | 2 +-
src/backend/executor/execTuples.c | 2 +-
src/backend/executor/tstoreReceiver.c | 2 +-
src/backend/replication/logical/reorderbuffer.c | 2 +-
src/backend/statistics/extended_stats.c | 2 +-
src/backend/storage/large_object/inv_api.c | 3 +-
src/backend/utils/adt/array_typanalyze.c | 2 +-
src/backend/utils/adt/datum.c | 2 +-
src/backend/utils/adt/expandedrecord.c | 3 +-
src/backend/utils/adt/rowtypes.c | 2 +-
src/backend/utils/adt/tsgistidx.c | 2 +-
src/backend/utils/adt/varchar.c | 2 +-
src/backend/utils/adt/varlena.c | 2 +-
src/backend/utils/cache/catcache.c | 2 +-
src/backend/utils/fmgr/fmgr.c | 2 +-
src/bin/pg_resetwal/pg_resetwal.c | 2 +-
src/include/access/detoast.h | 92 +
src/include/access/{tuptoaster.h => heaptoast.h} | 112 +-
src/include/access/toast_internals.h | 54 +
src/pl/plpgsql/src/pl_exec.c | 2 +-
src/test/regress/regress.c | 2 +-
37 files changed, 2612 insertions(+), 2557 deletions(-)