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, 4 insertions, 56 deletions

diff --git a/contrib/pageinspect/gistfuncs.c b/contrib/pageinspect/gistfuncs.c
index 96e3cab1cc3..10d6dd44d4e 100644
--- a/contrib/pageinspect/gistfuncs.c
+++ b/contrib/pageinspect/gistfuncs.c
@@ -97,10 +97,6 @@ gist_page_items_bytea(PG_FUNCTION_ARGS)
 {
 	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	bool		randomAccess;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext oldcontext;
 	Page		page;
 	OffsetNumber offset;
 	OffsetNumber maxoff = InvalidOffsetNumber;
@@ -110,29 +106,7 @@ gist_page_items_bytea(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 errmsg("must be superuser to use raw page functions")));
 
-	/* 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_SYNTAX_ERROR),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
-	oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
-
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
-	tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	page = get_page_from_raw(raw_page);
 
@@ -173,7 +147,7 @@ gist_page_items_bytea(PG_FUNCTION_ARGS)
 		values[3] = BoolGetDatum(ItemIdIsDead(id));
 		values[4] = PointerGetDatum(tuple_bytea);
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 	}
 
 	return (Datum) 0;
@@ -185,11 +159,7 @@ gist_page_items(PG_FUNCTION_ARGS)
 	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
 	Oid			indexRelid = PG_GETARG_OID(1);
 	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
-	bool		randomAccess;
 	Relation	indexRel;
-	TupleDesc	tupdesc;
-	Tuplestorestate *tupstore;
-	MemoryContext oldcontext;
 	Page		page;
 	OffsetNumber offset;
 	OffsetNumber maxoff = InvalidOffsetNumber;
@@ -199,29 +169,7 @@ gist_page_items(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 				 errmsg("must be superuser to use raw page functions")));
 
-	/* 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_SYNTAX_ERROR),
-				 errmsg("materialize mode required, but it is not allowed in this context")));
-
-	/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
-	oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
-
-	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		elog(ERROR, "return type must be a row type");
-
-	randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
-	tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
-	rsinfo->returnMode = SFRM_Materialize;
-	rsinfo->setResult = tupstore;
-	rsinfo->setDesc = tupdesc;
-
-	MemoryContextSwitchTo(oldcontext);
+	SetSingleFuncCall(fcinfo, 0);
 
 	/* Open the relation */
 	indexRel = index_open(indexRelid, AccessShareLock);
@@ -272,7 +220,7 @@ gist_page_items(PG_FUNCTION_ARGS)
 			nulls[4] = true;
 		}
 
-		tuplestore_putvalues(tupstore, tupdesc, values, nulls);
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
 	}
 
 	relation_close(indexRel, AccessShareLock);