Simplify SRFs using materialize mode in contrib/ modules

9e98583 introduced a helper to centralize building their needed state
(tuplestore, tuple descriptors, etc.), checking for any errors.  This
commit updates all places of contrib/ that can be switched to use
SetSingleFuncCall() as a drop-in replacement, resulting in the removal
of a lot of boilerplate code in all the modules updated by this commit.

Per analysis, some places remain as they are:
- pg_logdir_ls() in adminpack/ uses historically TYPEFUNC_RECORD as
return type, and I suspect that changing it may cause issues at run-time
with some of its past versions, down to 1.0.
- dblink/ uses a wrapper function doing exactly the work of
SetSingleFuncCall().  Here the switch should be possible, but rather
invasive so it does not seem the extra backpatch maintenance cost.
- tablefunc/, similarly, uses multiple helper functions with portions of
SetSingleFuncCall() spread across the code paths of this module.

Author: Melanie Plageman
Discussion: https://postgr.es/m/CAAKRu_bvDPJoL9mH6eYwvBpPtTGQwbDzfJbCM-OjkSZDu5yTPg@mail.gmail.com

1 files changed, 2 insertions, 29 deletions

diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 8c64d42dda2..74d3e732055 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -1661,37 +1661,10 @@ postgres_fdw_get_connections(PG_FUNCTION_ARGS)
 {
 #define POSTGRES_FDW_GET_CONNECTIONS_COLS	2
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext per_query_ctx;
-	MemoryContext oldcontext;
 	HASH_SEQ_STATUS scan;
 	ConnCacheEntry *entry;
 
-	/* check to see if caller supports us returning a tuplestore */
-	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that cannot accept a set")));
-	if (!(rsinfo->allowedModes & SFRM_Materialize))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* Build a tuple descriptor for our result type */
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	/* Build tuplestore to hold the result rows */
-	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
-	oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
-	tupstore = tuplestore_begin_heap(true, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* If cache doesn't exist, we return no records */
 	if (!ConnectionHash)
@@ -1757,7 +1730,7 @@ postgres_fdw_get_connections(PG_FUNCTION_ARGS)
 
 		values[1] = BoolGetDatum(!entry->invalidated);
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 	}